Effect of Time and Photoactivated Face on Bond Strength of Brackets and on Degree of Monomer Conversion

Effect of Time and Photoactivated Face on Bond Strength of Brackets and on Degree of Monomer Conversion | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of Time and Photoactivated Face on Bond Strength of Brackets and on Degree of Monomer Conversion Itanielly Dantas Silveira Cruz, Lorena Marques Ferreira de Sena, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3973509/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Aug, 2024 Read the published version in Clinical Oral Investigations → Version 1 posted 9 You are reading this latest preprint version Abstract Objective was to evaluate the effect of different photoactivation protocols of a high-power photo activator on the shear bond strength (SBS) between metal brackets and dental enamel and on the degree of conversion (DC) of an orthodontic resin. Material and Methods 40 bovine incisor crowns were randomly assigned to 4 groups (n = 10). The brackets were bonded with Transbond XT® resin using 4 protocols according to the “photoactivation protocol” factor which was subdivided into: photoactivated faces and photoactivation time. All the samples were stored for 4 months (water,37ºC) and then subjected to a SBS test (100KgF,1mm/min). 40 resin discs were made to evaluate the monomer degree of conversion. Data from the SBS and DC were assessed by One-way ANOVA and Tukey’s test (5%). Bond failures were analyzed according to the Adhesive Remnant Index (ARI) and evaluated by the Kruskal-Wallis test (5%). Results One protocol showed a clinically acceptable SBS value. There was a statistically significant difference (p = 0.008) in the One-way ANOVA result for SBS values, but the protocols showed statistically similar results (p ≥ 0.05–Tukey’s tests) concerning the photoactivated faces and photoactivation time factors individually. There was no statistically significant difference (p ≥ 0.05) in the One-way ANOVA result for DC values. Conclusion The SBS and DC values will vary depending on the protocol applied and 6 seconds-centered activation seems to be the most suitable for clinical practice. Clinical Relevance : It is possible to maintain the bracket fixation quality with the use of a high-power LED photo activator associated with a shorter photoactivation time. orthodontic brackets spectroscopy fourier transform infrared shear strength Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 INTRODUCTION The clinical procedure usually executed to bond brackets to the teeth enamel surface is performed by applying light cured composite resin to its base. The photoactivation is necessary to convert the resin’s monomers into polymeric chains, constituting a process described as degree of conversion which ensures maintaining the physical, chemical, biological and esthetic properties of resins [ 1 – 3 ]. Light emitting diode (LED) devices proposed by Mills, Jandt and Asworth (1999)[ 4 ] are currently the most widely used and are also increasing in technological evolution [ 5 , 6 ]. Considering that energy density is the result of multiplying irradiation time versus light intensity (mW/cm 2 ), some authors have proposed to reduce the photoactivation time of the devices by increasing their potency to maintain the degree of resin conversion within the adequate standard [ 7 , 8 ]. However, this reduction in photoactivation time associated with higher photo activator potency does not mean that the bonding of the orthodontic accessory will be satisfactory [ 3 , 7 , 9 , 10 ], as the degree of conversion depends on: light wavelength of the devices, intensity of irradiation, exposure time and the distance between the photo activator tip and the resin [ 6 , 11 ]. In this context, the shear mechanical test is one of the most established methods in the literature to evaluate the bracket fixation to the tooth. According to Reynolds (1975) [ 12 ], the adhesion strength appropriate for clinical use should be 5.9 to 7.8 MPa. Such value should not be too low, as it would result in detachment during treatment, and not too high, as removal of the bracket could cause irreversible damage to the enamel, such as cracks and/or fractures [ 13 , 14 ]. The detachment of brackets is an inherent aspect in the orthodontic practice and frustrating for both practitioner and patient, resulting in increased treatment time and additional cost of materials and fees [ 15 ]. In view of the scientific findings and the absence of a well-defined clinical bonding protocol in Orthodontics, it is assumed that the number of bracket faces in which the orthodontist positions the photo activator and/or the total time used in this step may affect the attachment quality of the accessory and the degree of conversion of the resin used. Thus, this study aimed to analyze the effect of different photoactivation protocols of a high-power photo activator ( Valo Cordless ®-Ultradent) on the degree of conversion (DC) of an orthodontic resin and on the shear bond strength (SBS) between metal brackets and dental enamel. Valo ® was chosen because in Xtra power mode (used in this study) it works with its greatest power (3,200 mW/cm 2 ) and a photoactivation time of 3 seconds. MATERIALS AND METHODS This research was approved (certificate n. ###) by the Animal Use Ethics Committee of the ###. Non-probabilistic intentional samples were used because the quantity of n = 10 is a standard value for laboratory studies in dentistry with good sample power [ 3 , 9 , 11 , 14 ]. In the present study, the power of the sample was calculated using the website (OpenEpi, version 3.01). First, 40 permanent lower bovine incisors, visually free of cracks and/or fractures and with a post-extraction time of less than one month were used for the SBS test [ 16 ]. Adhered soft or hard tissues were removed with periodontal curettes. The roots were sectioned with double-sided diamond disc (Microdont, São Paulo, SP, Brazil) and discarded (Fig. 1 A). The crowns were stored in distilled water at 4ºC [ 16 ]. Each crown was included in chemically activated acrylic resin ( Vipiflash ® and Ortocor ®, Vipi, Pirassununga, SP, Brazil) using a prefabricated rectangular industrial silicone mold ( Silicone Master ®, Talmax, Curitiba, PR, Brazil). The buccal face of the crown was in contact with the mold base. Taking into consideration ISO/TS 11405 (2003) [ 16 ], an area was minimally and carefully planned to even out the enamel surface without removing it excessively (Figs. 1 B- 1 C) using sandpapers of different granulations progressively (#200, 400 and 600) for 10 seconds/each and under constant water irrigation on an Aropol 2V-PU ® metallographic sander/polisher (Arotec, Cotia, SP, Brazil). After planning, enamel prophylaxis was performed for 10 seconds with a low speed micromotor, rubber cup, pumice stone and water. The crowns were then washed with water until the pumice stone paste was completely removed and air dried for 10 seconds. The exposed vestibular surface area was delimited by an insulating tape ( Scotch ®, 3M, Sumaré, SP, Brazil) with a 4.5 mm diameter hole. Next, conditioning with phosphoric acid 37% ( Condac 37 ®, FGM, Joinville, SC, Brazil) was performed for 15 seconds. The acid was removed with water (30 seconds), and the enamel was blast air-dried for 5 seconds. The Transbond XT ® Primer was applied with a microbrush ( Brushfine ®, KG Sorensen, Cotia, SP, Brazil), and excess adhesive was removed for 2 seconds. The 40 crowns were randomly distributed for bracket bonding according to 4 photoactivation protocols (Table 1 ), which were subdivided into: “photoactivated faces” (center, mesial/distal/cervical/incisal, mesial/distal or cervical/incisal) and “photoactivation time” (6 or 3 seconds). The description of the bonding material used is shown in Table 2 . Table 1 – Photoactivation protocols performed during bracket bonding according to photoactivated faces and photoactivation time on each face. PHOTOACTIVATION PROTOCOLS VALO CORDLESS® (N = 40/n = 10) • V3C = 3 seconds on center • VC6 = 6 seconds on center • V3M3D = 3 seconds on mesial + 3 seconds on distal • V3C3I = 3 seconds on cervical + 3 seconds on incisal Table 2 – Bonding materials used in this study. MATERIAL/LOT MANUFACTURER COMPOSITION % BY WEIGHT Transbond XT® Primer Lot N668081 3M Unitek (Monrovia, CA, USA) - BisGMA - TEDMA - Triphenyl antimony − (4-dimethylamine) -benzenethanol - DL-Caforquinone - Hydroquinone 45–55* 45–55* < 1* < 0,5* < 0,3* < 0,03* Transbond XT® Adhesive Paste Lots N660371 N763291 3M Unitek (Monrovia, CA, USA) - Treated silane quartz - BisGMA - Bisphenol A Dimethacrylate Bis (2-hydroxyethyl ether) - Treated silane silica - Diphenyliodonium hexafluorophosphate * Photoinitiating component: Camphorquinone (400-500nm) 70–80* 10–20* 5–10* < 2* < 0,2* BisGMA: Bisphenol A Dimethacrylate A diglycidyl ether; TEGDMA: Dimethylacrylate triethylene glycol; HEMA: 2-Hydroxyethyl methacrylate. * The specific chemical identity and/or exact percentage of this composition is a trade secret. An Edgewise Slim ® prescription lower incisor bracket (Morelli, Sorocaba, SP, Brazil) was positioned perpendicular to the long axis of the tooth with Transbond XT ® Adhesive Paste orthodontic resin at its base. Excess resin was removed with an explorer probe no.5 (SSWhite Duflex, Rio de Janeiro, RJ, Brazil). Light exposure was directed so that the tip of the photo activator gently touched the bracket surface, ensuring that its position was not altered. The insulating tape was removed at the end. The samples were stored in an incubator (37°C) in distilled water containers (one/each group) for 4 months to achieve the required aging prior to the SBS test, this was performed to keep them in an environment similar to the oral cavity and lasted 4 months aimed not to exceed 6 months before the shear bond test, as recommended by ISO/TS 11405 (2003) [ 16 ]. The shear test was performed on a Zwick Roell ® universal testing machine (Zwick Roell, Ulm, Germany) with a 100 Kgf load cell coupled to a device that vertically focused on the bracket/enamel interface (Fig. 1 D) at a constant speed of 1 mm/minute until fracture occurred. The force required to remove the bracket was generated in Newton (N) and converted to Megapascal (MPa) according to the formula: [SBS(MPa) = F(N)⁄A(mm 2 )]. Where “ A ” is the bracket base area of 9.24 mm 2 as measured with a digital caliper (Mitutoyo, Suzano, SP, Brazil. Accuracy: ± 0.02 mm). The types of union failure were evaluated in a stereomicroscope (Nikon SMZ800, Tokyo, Japan) and analyzed according to the Adhesive Remnant Index (ARI) proposed by Bishara and Trulove (1990) [ 17 ]: Score 1) All the resin was in the enamel; Score 2) More than 90% of the resin was in the enamel; Score 3) More than 10% and less than 90% of the resin was in the enamel; Score 4) Less than 10% of the resin was in the enamel; Score 5) No resin was left in the enamel. The Kappa Index (K) was also to evaluate the agreement with a reevaluation of 13% of the sample after 15 days. For illustrative purposes, representative samples of each of the scores found were observed in Scanning Electron Microscopy/SEM ® (TM3000, HITACHI, Tokyo, Japan) at 30x magnification. Next, 40 resin discs were made with the same photoactivation protocols used in the SBS analysis for the DC analysis. Using an insertion spatula no.1 (SSWhite Duflex, Rio de Janeiro, RJ, Brazil), a segment of approximately 2 mm of the Transbond XT ® adhesive paste was placed on a glass blade for microscopy. Then, it was fixed to the glass blade a polyester strip (Preven, Guapirama, PR, Brazil) with a metal bracket, which had been previously fixed to the strip with cyanoacrylate-based adhesive ( Super Bonder ®, Loctite, Diadema, SP, Brazil), so that no movement occurred during the photoactivation phase (Fig. 2 A). A force was gradually applied with the spatula inserted into the bracket slot to form a resin disc of 0.1 mm thick and an average of 5 mm in diameter (Fig. 2 B). Then, photoactivation was performed according to the 4 protocols (Table 1 ), simulating the bonding on the tooth enamel. The polyester strip was subsequently removed, cleaned with 70% alcohol (Quality Vic Pharma, Taquaritinga, SP, Brazil) and reserved for making the next disc. Each disc was carefully removed with a 15C scalpel (Lamedid Solidor, Osasco, SP, Brazil) attached to a scalpel handle nº 3 (Golgran, São Caetano do Sul, SP, Brazil) and stored for 24 hours in a black opaque container (Figs. 2 C- 2 E). After disc removal, the glass blade was cleaned with sterile cotton (Cremer, São Paulo, SP, Brazil) and 70% alcohol and then dried with sterile cotton. Measurements to determine DC were performed by a Fourier Transform Infrared Spectrophotometer - FT-IR ( IRAffinity-1 ®, Shimadzu, Tokyo, Japan) equipped with attenuated total reflectance device (ZATS prism HIR MIRacle module, PIKE Technologies, Madison, WI, USA). All specimens were positioned in the center of the spectrophotometer window (Figs. 2 F- 2 G). The spectra were measured using a Shimadzu IRsolution 1.60 ® (Shimadzu Corporation, 2011). The results of each sample were initially normalized, so that the baseline was adjusted. Spectra were obtained under the following conditions: Mode of absorbance; Number of scans: 32; Range: 700–4000 cm − 1 ; Resolution: 4 cm − 1 . With the peak absorption height data at 1637 and 1608 cm − 1 for polymerized and unpolymerized samples [ 18 ], the values were entered into the following equation: [DC(%) = 1–R(1637/1608) polymerized sample/R(1637/1608) unpolymerized sample)x100]. For unpolymerized samples, 10 segments of approximately 2 mm of the Transbond XT ® were individually placed in the center of the spectrophotometer window for analysis. Finally, data from these samples were averaged and the standard values were defined for the 1637 and 1608 cm − 1 peaks of the “unpolymerized sample”. The research database was built in Microsoft Excel ® software version 2016 (Microsoft Corporation, Redmond, USA), and the Statistical Package for Social Sciences ® (version 20.0 – IBM SPSS Statistics 20) was used for statistical analysis. The results of the shear test and of the degree of conversion were analyzed descriptively and by One-way Analysis of Variance (ANOVA) and Tukey’s test. The bonding failure scores analyzed according to the ARI were evaluated descriptively and using the Kruskal-Wallis test. A significance level of 5% was considered in all cases. The methodology was meticulously carried out and followed what is scientifically established in the literature to avoid possible errors regarding the evaluation of shear bond strength and the degree of conversion using brackets and orthodontic resins. All machines and equipment used in this research were evaluated, tested, and calibrated before each methodological step of this study. RESULTS Considering the differences in means between the V3C and V3M3D groups and their standard deviations, the power of the sample for the shear strength test was estimated at 84.6% with a 95% confidence interval, representing a good sample power. Table 3 shows the power verified by using a radiometer with sensitivity varying from 0 to 3000 mW/cm 2 , and the power reported by the manufacturer. Table 3 – Characteristics of photo activator used in this study and the powers according to the manufacturer and measured on the radiometer. NAME AND MANUFACTURER WAVELENGTH POWER According to the manufacturer According to radiometer and use of protection tip, if has (Mandatory use according to manual) Valo Cordless® – Ultradent (South Jordan, Utah, USA) 395–480 nm (Peak range: 400 e 460nm) 3.200 mW/cm 2 – Mode Xtra power (Used in this study) 2.600 mW/cm 2 (The Valo does not have a tip) The means and standard deviations of the SBS (MPa) are represented in Fig. 3 . The value of the V6C protocol is part of the range of SBS values considered clinically acceptable [ 12 ]. The mean values were significantly affected ( p = 0.008) according to the One-way ANOVA (Table 4 ). One group (V3C3I) presented pre-test failure (bracket detachment) to the shear test and consequently in the ARI analysis, wherein two specimens were lost. Table 4 – Results of Analysis of Variance (ANOVA) one-way and Tukey test according to the values of shear bond strength (MPa) and of degree of conversion (%). VARIABLE ANOVA ONE-WAY TUKEY TEST 95% CONFIDENCE INTERVAL SQ GL MQ F p PROTOCOLS p LOWER BOUND UPPER BOUND SBS (MPa) Between Groups 142.221 3 47.407 4.701 0.008* V3C V6C V3M3D V3C3I 0.311 0.023* 0.010* -1.3406 0.4633 0.9826 6.3304 8.1343 9.1189 Within Groups 342.850 34 10.084 V6C V3C V3M3D V3C3I 0.311 0.588 0.341 -6.3304 -2.0316 -1.5124 1.3406 5.6394 6.6239 Total 485.071 37 V3M3D V3C V6C V3C3I 0.023* 0.588 0.959 -8.1343 -5.6394 -3.3163 -0.4633 2.0316 4.8200 V3C3I V3C V6C V3M3D 0.010* 0.341 0.959 -9.1189 -6.6239 -4.8200 -0.9826 1.5124 3.3163 DC (%) Between Groups 201.167 3 67.056 0.546 0.654 V3C V6C V3M3D V3C3I ≥ 1.000 0.875 0.719 -13.1005 -9.6169 -8.1179 13.5871 17.0707 18.5696 Within Groups 4418.596 36 122.739 V6C V3C V3M3D V3C3I ≥ 1.000 0.895 0.747 -13.5871 -9.8602 -8.3612 13.1005 16.8274 18.3263 Total 4619.763 39 V3M3D V3C V6C V3C3I 0.875 0.895 0.990 -17.0707 -16.8274 -11.8448 9.6169 9.8602 14.8427 V3C3I V3C V6C V3M3D 0.719 0.747 0.990 -18.5696 -18.3263 -14.8427 8.1179 8.3612 11.8448 SBS: shear bond strength; DC: degree of conversion; SQ: sum of squares; GL: degrees of freedom; MQ: mean squares; F: F value; p: p value. *Statistically significant difference at the 5% level – (* p < 0.05). There was a statistically significant difference ( p = 0.000) in relation to the ARI (Table 5 ) scores according to the Kruskal-Wallis test, and the score 5 was observed in 52.6% of the sample. Intra-examiner calibration was performed and assessed by calculating the Kappa Index with a reevaluation of 13% of the sample after 15 days (K = 0.85). Figures 4 illustrate an example of each type of ARI failure found by images obtained from brackets and dental enamels in a stereomicroscope and scanning electron microscope. Table 5 – Distribution of Adhesive Remnant Index (ARI) scores by experimental group and total (n, %). PROTOCOL n S1 S2 S3 S4 S5 V3C 10 0 (0%) 5 (50%) 1 (10%) 2 (20%) 2 (20%) V6C 10 0 (0%) 1 (10%) 1 (10%) 2 (20%) 6 (60%) V3M3D 10 0 (0%) 1 (10%) 2 (20%) 0 (0%) 7 (70%) V3C3I 8 0 (0%) 0 (0%) 0 (0%) 3 (37,5%) 5 (62.5%) TOTAL N = 38 0 (0%) 7 (18.4%) 4 (10.5%) 7 (18.4%) 20 (52.6%) S: Score; S1 - all resin was in the enamel; S2 - more than 90% of the resin was in the enamel; S3 - more than 10% and less than 90% of the resin was in the enamel; S4 - less than 10% of the resin was in the enamel; S5 - no resin was in the enamel. The means and standard deviations of the DC (%) are represented in Fig. 5 . The average values were not significantly affected ( p = 0.654) according to the One-way ANOVA (Table 4 ). DISCUSSION Only one of the protocols presented clinically acceptable SBS value according to the literature (5.9 to 7.8 MPa)[ 12 ]: V6C – 6 seconds on center. This finding supports the results of previous studies [ 19 , 20 ] which showed bracket fixation quality maintained using high-power LED photo activator associated with a shorter photoactivation time. However, it is important to highlight that the SBS values will vary depending on the protocol applied. Two values obtained correspond to SBS less than 5.9 MPa, which implies a greater risk of bracket detachment and consequently a delay in treatment and increase in expenses with materials and fees [ 15 , 21 ]. Considering the result of the statistical analyses for the two groups where the photoactivation was performed only in the center, the SBS values were not significantly affected ( p = 0.311) by the “photoactivation time” (6 or 3 seconds) factor, but they were the protocols which resulted in the overall highest SBS value. The energy density is the result of multiplying the irradiation time versus the light intensity (mW/cm 2 ), but the variation in time was small enough to have no effect, and it is assumed that the high power by the Valo Cordless ® was able to result in higher SBS values. Regarding the “photoactivated faces” factor, the three protocols with 6 seconds showed statistically similar results for SBS and lower values than the 3 seconds on center, which was not expected since the light intensity and energy density vary depending on the face and the photoactivation time [ 6 , 7 , 11 , 22 , 23 ], respectively; the metallic bracket alone prevents light dissipation due to its opacity, and the enamel-resin-bracket interface is exposed to light with less intensity because of the greater distance from the tip of the photo activator [ 6 , 11 , 23 ]. When comparing the groups where only 2 faces were photoactivated, the one in which the pair of faces corresponded to distal/mesial was the protocol which resulted in higher SBS value. Similarly, the highest DC value was obtained when such faces were distal/mesial. This was probably due to the fact that the bracket used in the present study was for the lower incisor. Its vertical length is greater than the horizontal length. Thus, higher SBS and DC values tend to be obtained as a larger area of the enamel-resin-bracket interface was exposed to the light source [ 6 , 7 , 11 , 23 ] However, special attention should be paid to this result, since photoactivation performed only on the mesial and distal faces can also generate smaller values depending on the bracket format used by the professional. Additionally, a very high SBS value is inappropriate for clinical practice. Thus, opting for the pair of faces where exposure to light is greater may not be the best choice. Concerning the DC, “photoactivated faces” and “photoactivation time” factors did not affect the obtained values ( p = 0.654). According to Amato et al. (2014)[ 3 ] the DC of the Transbond XT ® resin varies in the literature from 39–83%, and despite applying the conventional methodology for DC analysis (without the use of brackets) in their study, the authors also found significant differences ( p < 0.01) in the results in varying the times and powers of the photoactivators used. Although the values obtained in the present study were relatively low, this may be associated to the fact that the DC analysis was performed at the location corresponding to the center of the bracket base where there is the lowest light incidence [ 3 , 6 , 11 , 23 , 24 ] However, 50% of SBS values observed are enough for bracket fixation (> 5.9 MPa) when applying the same protocols. Converting resinous compound monomers into polymers which is necessary to maintain the bracket bonding quality mainly occurs at the edges of the accessory. This is a factor which must be considered by orthodontists when deciding which faces to photoactivate depending on the power of the device and the photoactivation time selected. According to the literature [ 3 , 7 , 9 , 25 ], the greater the power, the greater the number of photons which act on the resin and consequently the greater the DC. On the other hand, some studies [ 9 , 19 , 22 , 26 ] have concluded that time is more important than potency in the process of converting monomers. Therefore, the balance between these three factors (faces, time and potency) is important not to generate SBS values which are inappropriate for clinical practice. An ARI score of 5 was the most noted with statistically significant difference ( p = 0.000). This result is negative, since it is assumed that the adhesive force between dental enamel and resin is smaller than that between Transbond XT ® and metal bracket. Thus, the chances that the resin will remain on the tooth surface when removing the orthodontic appliance at the end of the treatment are lower, while the chances that this can cause irreversible damage to the enamel becomes higher. According to Landis and Koch (1977) [ 27 ], K values between 0.81-1.00 indicate almost perfect agreement. Therefore, although the quantitative stereomicroscope analysis was not performed, the K = 0.85 represented an excellent agreement. It is relevant to emphasize that bond strength on bovine enamel is lower (approximately 40%) [ 28 ] compared to human enamel, and this distinction might be considered to compare the present results with Reynold's values. Moreover, it is acknowledged that this study's limitations include the fact that it is a laboratory experiment and that it analyzed Transbond XT®'s DC using a novel methodology not seen in the scholarly literature. Based on these results and the absence of studies using the Valo Cordless® and method comparable to that described here to compare the values obtained, it was decided that it was crucial to conduct additional research to enable a more accurate assessment of the true impact of photoactivation protocols on the SBS and DC of Transbond XT® using the Valo Cordless®. CONCLUSION The V6C (6 seconds-centered activation) seems to be the most suitable for clinical practice. It is possible to maintain the bracket fixation quality with the use of a high-power LED photo activator associated with a shorter photoactivation time. However, the SBS values will vary depending on the applied protocol. Furthermore, there is a change in the DC of Transbond XT ® when using different photoactivation protocols. Declarations Author Contribution All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Itanielly Dantas Silveira Cruz, Lorena Marques Ferreira de Sena, Eloisa Cesario Fernandes, Mariana Cabral Moreno, Rodrigo Othávio de Assunção e Souza, Arthur César de Medeiros Alves, Sergei Godeiro Fernandes Rabelo Caldas and Hallissa Simplício. The first draft of the manuscript was written by Itanielly Dantas Silveira Cruz and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Ethics Approval and Consent to Participate This research was approved (certificate nº 106.021/2018) by the Animal Use Ethics Committee (CEUA) of the Federal University of Rio Grande do Norte. Funding The authors declare no was funding. 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Angle Orthod. 2004;74(2):245-50. Swanson T, Dunn WJ, Childers DE, Taloumis LJ. Shear bond strength of orthodontic brackets bonded with light-emitting diode curing units at various polymerization times. Am J Orthod Dentofacial Orthop. 2004;125(3):337-41. Li J. Effect of flexural strength of orthodontic resin cement on bond strength of metal brackets to enamel surfaces. Eur J Orthod. 2011;33(2):167-73. Amato P, Martins L, Gatti A, Pretel H, Martins R. Influence of different wavelengths peaks in LED units on the degree of conversion of orthodontic composites. Journal of the World Federation of Orthodontists. 2016;5:118-21. Peutzfeldt A, Asmussen E. Resin composite properties and energy density of light cure. J Dent Res. 2005;84(7):659-62. Dall'Igna CM, Marchioro EM, Spohr AM, Mota EG. Effect of curing time on the bond strength of a bracket-bonding system cured with a light-emitting diode or plasma arc light. Eur J Orthod. 2011;33(1):55-9. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159-74. Rüttermann S, Braun A, Janda R. Shear bond strength and fracture analysis of human vs. bovine teeth. PLoS One. 2013;8(3):e59181. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 05 Aug, 2024 Read the published version in Clinical Oral Investigations → Version 1 posted Editorial decision: Revision requested 21 Mar, 2024 Reviews received at journal 21 Mar, 2024 Reviewers agreed at journal 21 Mar, 2024 Reviews received at journal 20 Mar, 2024 Reviewers agreed at journal 28 Feb, 2024 Reviewers invited by journal 28 Feb, 2024 Editor assigned by journal 22 Feb, 2024 Submission checks completed at journal 22 Feb, 2024 First submitted to journal 20 Feb, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3973509","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":274808768,"identity":"f2a3fc68-aea0-40ac-9b02-488fcf12ebdc","order_by":0,"name":"Itanielly Dantas Silveira Cruz","email":"","orcid":"","institution":"Federal University of Rio Grande do Norte - UFRN","correspondingAuthor":false,"prefix":"","firstName":"Itanielly","middleName":"Dantas Silveira","lastName":"Cruz","suffix":""},{"id":274808769,"identity":"54651bee-b037-4915-976c-8ec16d17a264","order_by":1,"name":"Lorena Marques Ferreira de Sena","email":"","orcid":"","institution":"Federal University of Rio Grande do Norte - UFRN","correspondingAuthor":false,"prefix":"","firstName":"Lorena","middleName":"Marques Ferreira","lastName":"de Sena","suffix":""},{"id":274808770,"identity":"62a5d27d-f2b7-4516-a036-475eaa07a13d","order_by":2,"name":"Eloisa Cesario Fernandes","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1ElEQVRIiWNgGAWjYPACCQb29gYgbWBBghaeMwdAWiRIsIfnRgJEL0HAz3748IefeyzkeCSfX93wo0CCgb+9OwGvFsmetDTJnmcSxjzSOWU3e4AOkzhzdgNeLQY3eMwYeA5IJO6Xzkm7wQPUYiCRi1+L/Q3+zx//ALX0SJ5Ju/mHGC0GEjwM0iBbeiTYj90myhaJM2lm0jIHgH7hyWG7LQM0gaBf+NsPP/745kCdHA/78Wc33/yxkeNv78WvBQnwGIBJYpWDAPsDUlSPglEwCkbBCAIA1/lC0UhQXfoAAAAASUVORK5CYII=","orcid":"","institution":"Federal University of Rio Grande do Norte - UFRN","correspondingAuthor":true,"prefix":"","firstName":"Eloisa","middleName":"Cesario","lastName":"Fernandes","suffix":""},{"id":274808771,"identity":"bdd0cc02-19bc-4d30-82ed-a325741635c7","order_by":3,"name":"Mariana Cabral Moreno","email":"","orcid":"","institution":"Federal University of Rio Grande do Norte - UFRN","correspondingAuthor":false,"prefix":"","firstName":"Mariana","middleName":"Cabral","lastName":"Moreno","suffix":""},{"id":274808772,"identity":"769e3e76-bdd0-4ab3-9b8d-c314b98d2bcb","order_by":4,"name":"Rodrigo Othávio de Assunção e Souza","email":"","orcid":"","institution":"Federal University of Rio Grande do Norte - UFRN","correspondingAuthor":false,"prefix":"","firstName":"Rodrigo","middleName":"Othávio de Assunção e","lastName":"Souza","suffix":""},{"id":274808773,"identity":"8b530b54-ccfd-452f-8b37-fd4f8c72b63f","order_by":5,"name":"Arthur César de Medeiros Alves","email":"","orcid":"","institution":"Federal University of Rio Grande do Norte - UFRN","correspondingAuthor":false,"prefix":"","firstName":"Arthur","middleName":"César de Medeiros","lastName":"Alves","suffix":""},{"id":274808774,"identity":"89c8aee6-9955-43a2-8940-689b43b0227e","order_by":6,"name":"Sergei Godeiro Fernandes Rabelo Caldas","email":"","orcid":"","institution":"Federal University of Rio Grande do Norte - UFRN","correspondingAuthor":false,"prefix":"","firstName":"Sergei","middleName":"Godeiro Fernandes Rabelo","lastName":"Caldas","suffix":""},{"id":274808775,"identity":"224ae423-85ea-42c9-9d30-4ffa09ca1f04","order_by":7,"name":"Hallissa Simplício","email":"","orcid":"","institution":"Federal University of Rio Grande do Norte - UFRN","correspondingAuthor":false,"prefix":"","firstName":"Hallissa","middleName":"","lastName":"Simplício","suffix":""}],"badges":[],"createdAt":"2024-02-20 18:05:51","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3973509/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3973509/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00784-024-05854-5","type":"published","date":"2024-08-05T15:58:06+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":51623912,"identity":"b2fba4f2-ea18-462c-8499-a3566aad213b","added_by":"auto","created_at":"2024-02-26 06:46:59","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":332625,"visible":true,"origin":"","legend":"\u003cp\u003eA) Sectioning at the level of the cementoenamel junction. B) Planning in the metallographic sander/polisher. C) Aspect after the planning. D) Metal device used for the shear test with the specimen in position\u003c/p\u003e","description":"","filename":"Fig.1.png","url":"https://assets-eu.researchsquare.com/files/rs-3973509/v1/1b43d860948e28c78995346a.png"},{"id":51623913,"identity":"3950693d-c898-4c5f-8d41-4b92fc940569","added_by":"auto","created_at":"2024-02-26 06:46:59","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":288918,"visible":true,"origin":"","legend":"\u003cp\u003eA) Polyester strip with bracket in position. B) Appearance of resin in disk format. C) Disc removal with scalpel. D) Final aspect of the specimens. E) Storage in container insulated from external light. F) Specimen in the center of the window of Fourier Transform Infrared Spectrophotometer - FR-IR. G) Device adjusted to start measuring the DC\u003c/p\u003e","description":"","filename":"Fig.2.png","url":"https://assets-eu.researchsquare.com/files/rs-3973509/v1/e7fdd55a0a23507eb46f0773.png"},{"id":51623916,"identity":"704cc5b6-9622-4c46-acf6-845502977ab9","added_by":"auto","created_at":"2024-02-26 06:47:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":2386016,"visible":true,"origin":"","legend":"\u003cp\u003eBond strength means (MPa) and standard deviations with a 95% confidence interval.\u003c/p\u003e\n\u003cp\u003eSource: \u003cem\u003eIBM SPSS Statistics 20\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig.3.png","url":"https://assets-eu.researchsquare.com/files/rs-3973509/v1/93bd537c5d0e2fcdaf105737.png"},{"id":51623914,"identity":"51202e0e-ddfa-47a3-8467-553c8e664803","added_by":"auto","created_at":"2024-02-26 06:47:00","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":458560,"visible":true,"origin":"","legend":"\u003cp\u003eBracket (A, C) and dental enamel (B, D) images in stereomicroscope (25x) and scanning electron microscope (30x), respectively. 4.1) Illustrating score 2. 4.2) Illustrating score 3. 4.3) Illustrating score 4. 4.4) Illustrating score 5\u003c/p\u003e","description":"","filename":"Fig.4.png","url":"https://assets-eu.researchsquare.com/files/rs-3973509/v1/4a389721a6e1ead35a8dc2ef.png"},{"id":51623915,"identity":"753a759e-0fb2-40b1-993b-8c42b83db911","added_by":"auto","created_at":"2024-02-26 06:47:00","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":2174707,"visible":true,"origin":"","legend":"\u003cp\u003eConversion degree means (%) and standard deviations with a 95% confidence interval.\u003c/p\u003e\n\u003cp\u003eSource: \u003cem\u003eIBM SPSS Statistics 20\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig.5.png","url":"https://assets-eu.researchsquare.com/files/rs-3973509/v1/cbd3d122d15112d584c12d3b.png"},{"id":62298633,"identity":"8d89d08b-b8fa-498f-a4ab-03ebbab028bd","added_by":"auto","created_at":"2024-08-12 16:15:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":11967628,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3973509/v1/fb2a2023-5422-4906-aa6f-dd260343cd3f.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eEffect of Time and Photoactivated Face on Bond Strength of Brackets and on Degree of Monomer Conversion\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe clinical procedure usually executed to bond brackets to the teeth enamel surface is performed by applying light cured composite resin to its base. The photoactivation is necessary to convert the resin\u0026rsquo;s monomers into polymeric chains, constituting a process described as degree of conversion which ensures maintaining the physical, chemical, biological and esthetic properties of resins [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eLight emitting diode (LED) devices proposed by Mills, Jandt and Asworth (1999)[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] are currently the most widely used and are also increasing in technological evolution [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Considering that energy density is the result of multiplying irradiation time \u003cem\u003eversus\u003c/em\u003e light intensity (mW/cm\u003csup\u003e2\u003c/sup\u003e), some authors have proposed to reduce the photoactivation time of the devices by increasing their potency to maintain the degree of resin conversion within the adequate standard [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, this reduction in photoactivation time associated with higher photo activator potency does not mean that the bonding of the orthodontic accessory will be satisfactory [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], as the degree of conversion depends on: light wavelength of the devices, intensity of irradiation, exposure time and the distance between the photo activator tip and the resin [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this context, the shear mechanical test is one of the most established methods in the literature to evaluate the bracket fixation to the tooth. According to Reynolds (1975) [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], the adhesion strength appropriate for clinical use should be 5.9 to 7.8 MPa. Such value should not be too low, as it would result in detachment during treatment, and not too high, as removal of the bracket could cause irreversible damage to the enamel, such as cracks and/or fractures [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe detachment of brackets is an inherent aspect in the orthodontic practice and frustrating for both practitioner and patient, resulting in increased treatment time and additional cost of materials and fees [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In view of the scientific findings and the absence of a well-defined clinical bonding protocol in Orthodontics, it is assumed that the number of bracket faces in which the orthodontist positions the photo activator and/or the total time used in this step may affect the attachment quality of the accessory and the degree of conversion of the resin used.\u003c/p\u003e \u003cp\u003eThus, this study aimed to analyze the effect of different photoactivation protocols of a high-power photo activator (\u003cem\u003eValo Cordless\u003c/em\u003e\u0026reg;-Ultradent) on the degree of conversion (DC) of an orthodontic resin and on the shear bond strength (SBS) between metal brackets and dental enamel. \u003cem\u003eValo\u003c/em\u003e\u0026reg; was chosen because in Xtra power mode (used in this study) it works with its greatest power (3,200 mW/cm\u003csup\u003e2\u003c/sup\u003e) and a photoactivation time of 3 seconds.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cp\u003e This research was approved (certificate n. ###) by the Animal Use Ethics Committee of the ###. Non-probabilistic intentional samples were used because the quantity of n\u0026thinsp;=\u0026thinsp;10 is a standard value for laboratory studies in dentistry with good sample power [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In the present study, the power of the sample was calculated using the website\u0026thinsp;\u0026lt;\u0026thinsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ewww.openepi.com\u0026gt;\u003c/span\u003e\u003cspan address=\"http://www.openepi.com%3E\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (OpenEpi, version 3.01).\u003c/p\u003e \u003cp\u003eFirst, 40 permanent lower bovine incisors, visually free of cracks and/or fractures and with a post-extraction time of less than one month were used for the SBS test [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Adhered soft or hard tissues were removed with periodontal curettes. The roots were sectioned with double-sided diamond disc (Microdont, S\u0026atilde;o Paulo, SP, Brazil) and discarded (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA). The crowns were stored in distilled water at 4\u0026ordm;C [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eEach crown was included in chemically activated acrylic resin (\u003cem\u003eVipiflash\u003c/em\u003e\u0026reg; and \u003cem\u003eOrtocor\u003c/em\u003e\u0026reg;, Vipi, Pirassununga, SP, Brazil) using a prefabricated rectangular industrial silicone mold (\u003cem\u003eSilicone Master\u003c/em\u003e\u0026reg;, Talmax, Curitiba, PR, Brazil). The buccal face of the crown was in contact with the mold base.\u003c/p\u003e \u003cp\u003eTaking into consideration ISO/TS 11405 (2003) [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], an area was minimally and carefully planned to even out the enamel surface without removing it excessively (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB-\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC) using sandpapers of different granulations progressively (#200, 400 and 600) for 10 seconds/each and under constant water irrigation on an \u003cem\u003eAropol 2V-PU\u003c/em\u003e\u0026reg; metallographic sander/polisher (Arotec, Cotia, SP, Brazil).\u003c/p\u003e \u003cp\u003eAfter planning, enamel prophylaxis was performed for 10 seconds with a low speed micromotor, rubber cup, pumice stone and water. The crowns were then washed with water until the pumice stone paste was completely removed and air dried for 10 seconds. The exposed vestibular surface area was delimited by an insulating tape (\u003cem\u003eScotch\u003c/em\u003e\u0026reg;, 3M, Sumar\u0026eacute;, SP, Brazil) with a 4.5 mm diameter hole.\u003c/p\u003e \u003cp\u003eNext, conditioning with phosphoric acid 37% (\u003cem\u003eCondac 37\u003c/em\u003e\u0026reg;, FGM, Joinville, SC, Brazil) was performed for 15 seconds. The acid was removed with water (30 seconds), and the enamel was blast air-dried for 5 seconds. The \u003cem\u003eTransbond XT\u003c/em\u003e\u0026reg; Primer was applied with a microbrush (\u003cem\u003eBrushfine\u003c/em\u003e\u0026reg;, KG Sorensen, Cotia, SP, Brazil), and excess adhesive was removed for 2 seconds.\u003c/p\u003e \u003cp\u003eThe 40 crowns were randomly distributed for bracket bonding according to 4 photoactivation protocols (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), which were subdivided into: \u0026ldquo;photoactivated faces\u0026rdquo; (center, mesial/distal/cervical/incisal, mesial/distal or cervical/incisal) and \u0026ldquo;photoactivation time\u0026rdquo; (6 or 3 seconds). The description of the bonding material used is shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u0026ndash; Photoactivation protocols performed during bracket bonding according to photoactivated faces and photoactivation time on each face.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"1\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePHOTOACTIVATION PROTOCOLS\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVALO CORDLESS\u0026reg;\u003c/p\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;40/n\u0026thinsp;=\u0026thinsp;10)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026bull; V3C\u0026thinsp;=\u0026thinsp;3 seconds on center\u003c/p\u003e \u003cp\u003e\u0026bull; VC6\u0026thinsp;=\u0026thinsp;6 seconds on center\u003c/p\u003e \u003cp\u003e\u0026bull; V3M3D\u0026thinsp;=\u0026thinsp;3 seconds on mesial\u0026thinsp;+\u0026thinsp;3 seconds on distal\u003c/p\u003e \u003cp\u003e\u0026bull; V3C3I\u0026thinsp;=\u0026thinsp;3 seconds on cervical\u0026thinsp;+\u0026thinsp;3 seconds on incisal\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u0026ndash; Bonding materials used in this study.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMATERIAL/LOT\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMANUFACTURER\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCOMPOSITION\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e% BY WEIGHT\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransbond XT\u0026reg; Primer\u003c/p\u003e \u003cp\u003eLot N668081\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3M Unitek\u003c/p\u003e \u003cp\u003e(Monrovia,\u003c/p\u003e \u003cp\u003eCA, USA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e- BisGMA\u003c/p\u003e \u003cp\u003e- TEDMA\u003c/p\u003e \u003cp\u003e- Triphenyl antimony\u003c/p\u003e \u003cp\u003e\u0026minus;\u0026thinsp;(4-dimethylamine) -benzenethanol\u003c/p\u003e \u003cp\u003e- DL-Caforquinone\u003c/p\u003e \u003cp\u003e- Hydroquinone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45\u0026ndash;55*\u003c/p\u003e \u003cp\u003e45\u0026ndash;55*\u003c/p\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1*\u003c/p\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0,5*\u003c/p\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0,3*\u003c/p\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0,03*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransbond XT\u0026reg;\u003c/p\u003e \u003cp\u003eAdhesive Paste\u003c/p\u003e \u003cp\u003eLots\u003c/p\u003e \u003cp\u003eN660371\u003c/p\u003e \u003cp\u003eN763291\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3M Unitek\u003c/p\u003e \u003cp\u003e(Monrovia,\u003c/p\u003e \u003cp\u003eCA, USA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e- Treated silane quartz\u003c/p\u003e \u003cp\u003e- BisGMA\u003c/p\u003e \u003cp\u003e- Bisphenol A Dimethacrylate Bis (2-hydroxyethyl ether)\u003c/p\u003e \u003cp\u003e- Treated silane silica\u003c/p\u003e \u003cp\u003e- Diphenyliodonium hexafluorophosphate\u003c/p\u003e \u003cp\u003e* Photoinitiating component: Camphorquinone (400-500nm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e70\u0026ndash;80*\u003c/p\u003e \u003cp\u003e10\u0026ndash;20*\u003c/p\u003e \u003cp\u003e5\u0026ndash;10*\u003c/p\u003e \u003cp\u003e\u0026lt;\u0026thinsp;2*\u003c/p\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0,2*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eBisGMA: Bisphenol A Dimethacrylate A diglycidyl ether; TEGDMA: Dimethylacrylate triethylene glycol; HEMA: 2-Hydroxyethyl methacrylate.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e* The specific chemical identity and/or exact percentage of this composition is a trade secret.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAn \u003cem\u003eEdgewise Slim\u003c/em\u003e\u0026reg; prescription lower incisor bracket (Morelli, Sorocaba, SP, Brazil) was positioned perpendicular to the long axis of the tooth with \u003cem\u003eTransbond XT\u003c/em\u003e\u0026reg; Adhesive Paste orthodontic resin at its base. Excess resin was removed with an explorer probe no.5 (SSWhite Duflex, Rio de Janeiro, RJ, Brazil). Light exposure was directed so that the tip of the photo activator gently touched the bracket surface, ensuring that its position was not altered. The insulating tape was removed at the end.\u003c/p\u003e \u003cp\u003eThe samples were stored in an incubator (37\u0026deg;C) in distilled water containers (one/each group) for 4 months to achieve the required aging prior to the SBS test, this was performed to keep them in an environment similar to the oral cavity and lasted 4 months aimed not to exceed 6 months before the shear bond test, as recommended by ISO/TS 11405 (2003) [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe shear test was performed on a \u003cem\u003eZwick Roell\u003c/em\u003e\u0026reg; universal testing machine (Zwick Roell, Ulm, Germany) with a 100 Kgf load cell coupled to a device that vertically focused on the bracket/enamel interface (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD) at a constant speed of 1 mm/minute until fracture occurred. The force required to remove the bracket was generated in Newton (N) and converted to Megapascal (MPa) according to the formula: [SBS(MPa)\u0026thinsp;=\u0026thinsp;F(N)\u0026frasl;A(mm\u003csup\u003e2\u003c/sup\u003e)]. Where \u0026ldquo;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eA\u003c/span\u003e\u0026rdquo; is the bracket base area of 9.24 mm\u003csup\u003e2\u003c/sup\u003e as measured with a digital caliper (Mitutoyo, Suzano, SP, Brazil. Accuracy: \u0026plusmn; 0.02 mm).\u003c/p\u003e \u003cp\u003eThe types of union failure were evaluated in a stereomicroscope (Nikon SMZ800, Tokyo, Japan) and analyzed according to the Adhesive Remnant Index (ARI) proposed by Bishara and Trulove (1990) [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]: Score 1) All the resin was in the enamel; Score 2) More than 90% of the resin was in the enamel; Score 3) More than 10% and less than 90% of the resin was in the enamel; Score 4) Less than 10% of the resin was in the enamel; Score 5) No resin was left in the enamel. The Kappa Index (K) was also to evaluate the agreement with a reevaluation of 13% of the sample after 15 days. For illustrative purposes, representative samples of each of the scores found were observed in \u003cem\u003eScanning Electron Microscopy/SEM\u003c/em\u003e\u0026reg; (TM3000, HITACHI, Tokyo, Japan) at 30x magnification.\u003c/p\u003e \u003cp\u003eNext, 40 resin discs were made with the same photoactivation protocols used in the SBS analysis for the DC analysis. Using an insertion spatula no.1 (SSWhite Duflex, Rio de Janeiro, RJ, Brazil), a segment of approximately 2 mm of the \u003cem\u003eTransbond XT\u003c/em\u003e\u0026reg; adhesive paste was placed on a glass blade for microscopy. Then, it was fixed to the glass blade a polyester strip (Preven, Guapirama, PR, Brazil) with a metal bracket, which had been previously fixed to the strip with cyanoacrylate-based adhesive (\u003cem\u003eSuper Bonder\u003c/em\u003e\u0026reg;, Loctite, Diadema, SP, Brazil), so that no movement occurred during the photoactivation phase (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA force was gradually applied with the spatula inserted into the bracket slot to form a resin disc of 0.1 mm thick and an average of 5 mm in diameter (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB). Then, photoactivation was performed according to the 4 protocols (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), simulating the bonding on the tooth enamel. The polyester strip was subsequently removed, cleaned with 70% alcohol (Quality Vic Pharma, Taquaritinga, SP, Brazil) and reserved for making the next disc.\u003c/p\u003e \u003cp\u003eEach disc was carefully removed with a 15C scalpel (Lamedid Solidor, Osasco, SP, Brazil) attached to a scalpel handle n\u0026ordm; 3 (Golgran, S\u0026atilde;o Caetano do Sul, SP, Brazil) and stored for 24 hours in a black opaque container (Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC-\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eE). After disc removal, the glass blade was cleaned with sterile cotton (Cremer, S\u0026atilde;o Paulo, SP, Brazil) and 70% alcohol and then dried with sterile cotton.\u003c/p\u003e \u003cp\u003eMeasurements to determine DC were performed by a Fourier Transform Infrared Spectrophotometer - FT-IR (\u003cem\u003eIRAffinity-1\u003c/em\u003e\u0026reg;, Shimadzu, Tokyo, Japan) equipped with attenuated total reflectance device (ZATS prism HIR MIRacle module, PIKE Technologies, Madison, WI, USA). All specimens were positioned in the center of the spectrophotometer window (Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eF-\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eG).\u003c/p\u003e \u003cp\u003eThe spectra were measured using a \u003cem\u003eShimadzu IRsolution 1.60\u003c/em\u003e\u0026reg; (Shimadzu Corporation, 2011). The results of each sample were initially normalized, so that the baseline was adjusted. Spectra were obtained under the following conditions: Mode of absorbance; Number of scans: 32; Range: 700\u0026ndash;4000 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e; Resolution: 4 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eWith the peak absorption height data at 1637 and 1608 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for polymerized and unpolymerized samples [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], the values were entered into the following equation: [DC(%)\u0026thinsp;=\u0026thinsp;1\u0026ndash;R(1637/1608) polymerized sample/R(1637/1608) unpolymerized sample)x100]. For unpolymerized samples, 10 segments of approximately 2 mm of the \u003cem\u003eTransbond XT\u003c/em\u003e\u0026reg; were individually placed in the center of the spectrophotometer window for analysis. Finally, data from these samples were averaged and the standard values were defined for the 1637 and 1608 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e peaks of the \u0026ldquo;unpolymerized sample\u0026rdquo;.\u003c/p\u003e \u003cp\u003eThe research database was built in \u003cem\u003eMicrosoft Excel\u003c/em\u003e\u003csup\u003e\u0026reg;\u003c/sup\u003e software version 2016 (Microsoft Corporation, Redmond, USA), and the \u003cem\u003eStatistical Package for Social Sciences\u003c/em\u003e\u003csup\u003e\u0026reg;\u003c/sup\u003e (version 20.0 \u0026ndash; IBM SPSS Statistics 20) was used for statistical analysis. The results of the shear test and of the degree of conversion were analyzed descriptively and by One-way Analysis of Variance (ANOVA) and Tukey\u0026rsquo;s test. The bonding failure scores analyzed according to the ARI were evaluated descriptively and using the Kruskal-Wallis test. A significance level of 5% was considered in all cases.\u003c/p\u003e \u003cp\u003e The methodology was meticulously carried out and followed what is scientifically established in the literature to avoid possible errors regarding the evaluation of shear bond strength and the degree of conversion using brackets and orthodontic resins. All machines and equipment used in this research were evaluated, tested, and calibrated before each methodological step of this study.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eConsidering the differences in means between the V3C and V3M3D groups and their standard deviations, the power of the sample for the shear strength test was estimated at 84.6% with a 95% confidence interval, representing a good sample power. Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the power verified by using a radiometer with sensitivity varying from 0 to 3000 mW/cm\u003csup\u003e2\u003c/sup\u003e, and the power reported by the manufacturer.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u0026ndash; Characteristics of photo activator used in this study and the powers according to the manufacturer and measured on the radiometer.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNAME AND MANUFACTURER\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eWAVELENGTH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003ePOWER\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAccording to the manufacturer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAccording to radiometer and use of protection tip, if has\u003c/p\u003e \u003cp\u003e(Mandatory use according to manual)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eValo Cordless\u0026reg; \u0026ndash; Ultradent (South Jordan, Utah, USA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e395\u0026ndash;480 nm\u003c/p\u003e \u003cp\u003e(Peak range: 400 e 460nm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.200 mW/cm\u003csup\u003e2\u003c/sup\u003e \u0026ndash; Mode Xtra power\u003c/p\u003e \u003cp\u003e(Used in this study)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.600 mW/cm\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e(The Valo does not have a tip)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe means and standard deviations of the SBS (MPa) are represented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The value of the V6C protocol is part of the range of SBS values considered clinically acceptable [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The mean values were significantly affected (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008) according to the One-way ANOVA (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). One group (V3C3I) presented pre-test failure (bracket detachment) to the shear test and consequently in the ARI analysis, wherein two specimens were lost.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u0026ndash; Results of Analysis of Variance (ANOVA) one-way and Tukey test according to the values of shear bond strength (MPa) and of degree of conversion (%).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"14\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVARIABLE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e \u003cp\u003eANOVA ONE-WAY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c11\" namest=\"c9\"\u003e \u003cp\u003eTUKEY TEST\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e95% CONFIDENCE INTERVAL\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMQ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003ePROTOCOLS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e\u003cem\u003eLOWER BOUND\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e\u003cem\u003eUPPER BOUND\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eSBS (MPa)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBetween Groups\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e142.221\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e47.407\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4.701\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.008*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eV6C\u003c/p\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.311\u003c/p\u003e \u003cp\u003e0.023*\u003c/p\u003e \u003cp\u003e0.010*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-1.3406\u003c/p\u003e \u003cp\u003e0.4633\u003c/p\u003e \u003cp\u003e0.9826\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e6.3304\u003c/p\u003e \u003cp\u003e8.1343\u003c/p\u003e \u003cp\u003e9.1189\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWithin Groups\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e342.850\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10.084\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eV6C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.311\u003c/p\u003e \u003cp\u003e0.588\u003c/p\u003e \u003cp\u003e0.341\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-6.3304\u003c/p\u003e \u003cp\u003e-2.0316\u003c/p\u003e \u003cp\u003e-1.5124\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e1.3406\u003c/p\u003e \u003cp\u003e5.6394\u003c/p\u003e \u003cp\u003e6.6239\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e485.071\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003cp\u003eV6C\u003c/p\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.023*\u003c/p\u003e \u003cp\u003e0.588\u003c/p\u003e \u003cp\u003e0.959\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-8.1343\u003c/p\u003e \u003cp\u003e-5.6394\u003c/p\u003e \u003cp\u003e-3.3163\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-0.4633\u003c/p\u003e \u003cp\u003e2.0316\u003c/p\u003e \u003cp\u003e4.8200\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003cp\u003eV6C\u003c/p\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.010*\u003c/p\u003e \u003cp\u003e0.341\u003c/p\u003e \u003cp\u003e0.959\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-9.1189\u003c/p\u003e \u003cp\u003e-6.6239\u003c/p\u003e \u003cp\u003e-4.8200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e-0.9826\u003c/p\u003e \u003cp\u003e1.5124\u003c/p\u003e \u003cp\u003e3.3163\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eDC (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBetween Groups\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e201.167\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e67.056\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.546\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.654\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eV6C\u003c/p\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;1.000\u003c/p\u003e \u003cp\u003e0.875\u003c/p\u003e \u003cp\u003e0.719\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-13.1005\u003c/p\u003e \u003cp\u003e-9.6169\u003c/p\u003e \u003cp\u003e-8.1179\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e13.5871\u003c/p\u003e \u003cp\u003e17.0707\u003c/p\u003e \u003cp\u003e18.5696\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWithin Groups\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4418.596\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e122.739\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eV6C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;1.000\u003c/p\u003e \u003cp\u003e0.895\u003c/p\u003e \u003cp\u003e0.747\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-13.5871\u003c/p\u003e \u003cp\u003e-9.8602\u003c/p\u003e \u003cp\u003e-8.3612\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e13.1005\u003c/p\u003e \u003cp\u003e16.8274\u003c/p\u003e \u003cp\u003e18.3263\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e4619.763\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003cp\u003eV6C\u003c/p\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.875\u003c/p\u003e \u003cp\u003e0.895\u003c/p\u003e \u003cp\u003e0.990\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-17.0707\u003c/p\u003e \u003cp\u003e-16.8274\u003c/p\u003e \u003cp\u003e-11.8448\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e9.6169\u003c/p\u003e \u003cp\u003e9.8602\u003c/p\u003e \u003cp\u003e14.8427\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003cp\u003eV6C\u003c/p\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e0.719\u003c/p\u003e \u003cp\u003e0.747\u003c/p\u003e \u003cp\u003e0.990\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e-18.5696\u003c/p\u003e \u003cp\u003e-18.3263\u003c/p\u003e \u003cp\u003e-14.8427\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e8.1179\u003c/p\u003e \u003cp\u003e8.3612\u003c/p\u003e \u003cp\u003e11.8448\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"14\"\u003eSBS: shear bond strength; DC: degree of conversion; SQ: sum of squares; GL: degrees of freedom; MQ: mean squares; F: F value; \u003cem\u003ep: p\u003c/em\u003e value.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"14\"\u003e*Statistically significant difference at the 5% level \u0026ndash; (*\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThere was a statistically significant difference (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.000) in relation to the ARI (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e) scores according to the Kruskal-Wallis test, and the score 5 was observed in 52.6% of the sample. Intra-examiner calibration was performed and assessed by calculating the Kappa Index with a reevaluation of 13% of the sample after 15 days (K\u0026thinsp;=\u0026thinsp;0.85). Figures\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e illustrate an example of each type of ARI failure found by images obtained from brackets and dental enamels in a stereomicroscope and scanning electron microscope.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u0026ndash; Distribution of Adhesive Remnant Index (ARI) scores by experimental group and total (n, %).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePROTOCOL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eS1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS4\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eS5\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eV3C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2 (20%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2 (20%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eV6C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2 (20%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6 (60%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eV3M3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2 (20%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7 (70%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eV3C3I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3 (37,5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5 (62.5%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTOTAL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN\u0026thinsp;=\u0026thinsp;38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (18.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 (10.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7 (18.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e20 (52.6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eS: Score; S1 - all resin was in the enamel; S2 - more than 90% of the resin was in the enamel; S3 - more than 10% and less than 90% of the resin was in the enamel; S4 - less than 10% of the resin was in the enamel; S5 - no resin was in the enamel.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe means and standard deviations of the DC (%) are represented in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. The average values were not significantly affected (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.654) according to the One-way ANOVA (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eOnly one of the protocols presented clinically acceptable SBS value according to the literature (5.9 to 7.8 MPa)[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]: V6C \u0026ndash; 6 seconds on center. This finding supports the results of previous studies [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] which showed bracket fixation quality maintained using high-power LED photo activator associated with a shorter photoactivation time. However, it is important to highlight that the SBS values will vary depending on the protocol applied. Two values obtained correspond to SBS less than 5.9 MPa, which implies a greater risk of bracket detachment and consequently a delay in treatment and increase in expenses with materials and fees [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eConsidering the result of the statistical analyses for the two groups where the photoactivation was performed only in the center, the SBS values were not significantly affected (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.311) by the \u0026ldquo;photoactivation time\u0026rdquo; (6 or 3 seconds) factor, but they were the protocols which resulted in the overall highest SBS value. The energy density is the result of multiplying the irradiation time \u003cem\u003eversus\u003c/em\u003e the light intensity (mW/cm\u003csup\u003e2\u003c/sup\u003e), but the variation in time was small enough to have no effect, and it is assumed that the high power by the \u003cem\u003eValo Cordless\u003c/em\u003e\u003csup\u003e\u0026reg;\u003c/sup\u003e was able to result in higher SBS values. Regarding the \u0026ldquo;photoactivated faces\u0026rdquo; factor, the three protocols with 6 seconds showed statistically similar results for SBS and lower values than the 3 seconds on center, which was not expected since the light intensity and energy density vary depending on the face and the photoactivation time [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], respectively; the metallic bracket alone prevents light dissipation due to its opacity, and the enamel-resin-bracket interface is exposed to light with less intensity because of the greater distance from the tip of the photo activator [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhen comparing the groups where only 2 faces were photoactivated, the one in which the pair of faces corresponded to distal/mesial was the protocol which resulted in higher SBS value. Similarly, the highest DC value was obtained when such faces were distal/mesial. This was probably due to the fact that the bracket used in the present study was for the lower incisor. Its vertical length is greater than the horizontal length.\u003c/p\u003e \u003cp\u003eThus, higher SBS and DC values tend to be obtained as a larger area of the enamel-resin-bracket interface was exposed to the light source [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] However, special attention should be paid to this result, since photoactivation performed only on the mesial and distal faces can also generate smaller values depending on the bracket format used by the professional. Additionally, a very high SBS value is inappropriate for clinical practice. Thus, opting for the pair of faces where exposure to light is greater may not be the best choice.\u003c/p\u003e \u003cp\u003eConcerning the DC, \u0026ldquo;photoactivated faces\u0026rdquo; and \u0026ldquo;photoactivation time\u0026rdquo; factors did not affect the obtained values (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.654). According to Amato et al. (2014)[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] the DC of the \u003cem\u003eTransbond XT\u003c/em\u003e\u003csup\u003e\u0026reg;\u003c/sup\u003e resin varies in the literature from 39\u0026ndash;83%, and despite applying the conventional methodology for DC analysis (without the use of brackets) in their study, the authors also found significant differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01) in the results in varying the times and powers of the photoactivators used.\u003c/p\u003e \u003cp\u003eAlthough the values obtained in the present study were relatively low, this may be associated to the fact that the DC analysis was performed at the location corresponding to the center of the bracket base where there is the lowest light incidence [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] However, 50% of SBS values observed are enough for bracket fixation (\u0026gt;\u0026thinsp;5.9 MPa) when applying the same protocols. Converting resinous compound monomers into polymers which is necessary to maintain the bracket bonding quality mainly occurs at the edges of the accessory.\u003c/p\u003e \u003cp\u003eThis is a factor which must be considered by orthodontists when deciding which faces to photoactivate depending on the power of the device and the photoactivation time selected. According to the literature [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], the greater the power, the greater the number of photons which act on the resin and consequently the greater the DC. On the other hand, some studies [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] have concluded that time is more important than potency in the process of converting monomers. Therefore, the balance between these three factors (faces, time and potency) is important not to generate SBS values which are inappropriate for clinical practice.\u003c/p\u003e \u003cp\u003eAn ARI score of 5 was the most noted with statistically significant difference (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.000). This result is negative, since it is assumed that the adhesive force between dental enamel and resin is smaller than that between \u003cem\u003eTransbond XT\u003c/em\u003e\u003csup\u003e\u0026reg;\u003c/sup\u003e and metal bracket. Thus, the chances that the resin will remain on the tooth surface when removing the orthodontic appliance at the end of the treatment are lower, while the chances that this can cause irreversible damage to the enamel becomes higher. According to Landis and Koch (1977) [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], K values between 0.81-1.00 indicate almost perfect agreement. Therefore, although the quantitative stereomicroscope analysis was not performed, the K\u0026thinsp;=\u0026thinsp;0.85 represented an excellent agreement.\u003c/p\u003e \u003cp\u003eIt is relevant to emphasize that bond strength on bovine enamel is lower (approximately 40%) [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] compared to human enamel, and this distinction might be considered to compare the present results with Reynold's values. Moreover, it is acknowledged that this study's limitations include the fact that it is a laboratory experiment and that it analyzed Transbond XT\u0026reg;'s DC using a novel methodology not seen in the scholarly literature. Based on these results and the absence of studies using the Valo Cordless\u0026reg; and method comparable to that described here to compare the values obtained, it was decided that it was crucial to conduct additional research to enable a more accurate assessment of the true impact of photoactivation protocols on the SBS and DC of Transbond XT\u0026reg; using the Valo Cordless\u0026reg;.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eThe V6C (6 seconds-centered activation) seems to be the most suitable for clinical practice.\u003c/p\u003e \u003cp\u003eIt is possible to maintain the bracket fixation quality with the use of a high-power LED photo activator associated with a shorter photoactivation time. However, the SBS values will vary depending on the applied protocol.\u003c/p\u003e \u003cp\u003eFurthermore, there is a change in the DC of \u003cem\u003eTransbond XT\u003c/em\u003e\u003csup\u003e\u0026reg;\u003c/sup\u003e when using different photoactivation protocols.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Itanielly Dantas Silveira Cruz, Lorena Marques Ferreira de Sena, Eloisa Cesario Fernandes, Mariana Cabral Moreno, Rodrigo Oth\u0026aacute;vio de Assun\u0026ccedil;\u0026atilde;o e Souza, Arthur C\u0026eacute;sar de Medeiros Alves, Sergei Godeiro Fernandes Rabelo Caldas and Hallissa Simpl\u0026iacute;cio. The first draft of the manuscript was written by Itanielly Dantas Silveira Cruz and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval and Consent to Participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was approved (certificate n\u0026ordm; 106.021/2018) by the Animal Use Ethics Committee (CEUA) of the Federal University of Rio Grande do Norte.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no was funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eACKNOWLEDGMENTS:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eTavas MA, Watts DC. Bonding of orthodontic brackets by transillumination of a light activated composite: an in vitro study. Br J Orthod. 1979;6(4):207-8.\u003c/li\u003e\n\u003cli\u003eSantini A, Miletic V, Swift MD, Bradley M. Degree of conversion and microhardness of TPO-containing resin-based composites cured by polywave and monowave LED units. J Dent. 2012;40(7):577-84.\u003c/li\u003e\n\u003cli\u003eAmato PA, Martins RP, dos Santos Cruz CA, Capella MV, Martins LP. Time reduction of light curing: Influence on conversion degree and microhardness of orthodontic composites. Am J Orthod Dentofacial Orthop. 2014;146(1):40-6.\u003c/li\u003e\n\u003cli\u003eMills RW, Jandt KD, Ashworth SH. Dental composite depth of cure with halogen and blue light emitting diode technology. Br Dent J. 1999;186(8):388-91.\u003c/li\u003e\n\u003cli\u003eCacciafesta V, Sfondrini MF, Scribante A, Boehme A, Jost-Brinkmann PG. Effect of light-tip distance on the shear bond strengths of composite resin. Angle Orthod. 2005;75(3):386-91.\u003c/li\u003e\n\u003cli\u003eUlusoy C, Irmak O, Bagis YH, Ulusoy OI. Temperature rise and shear bond strength of bondable buccal tubes bonded by various light sources. Eur J Orthod. 2008;30(4):413-7.\u003c/li\u003e\n\u003cli\u003eStaudt CB, Krejci I, Mavropoulos A. Bracket bond strength dependence on light power density. J Dent. 2006;34(7):498-502.\u003c/li\u003e\n\u003cli\u003eRueggeberg FA. State-of-the-art: dental photocuring--a review. Dent Mater. 2011;27(1):39-52.\u003c/li\u003e\n\u003cli\u003eNiepraschk M, Rahiotis C, Bradley TG, Eliades T, Eliades G. Effect of various curing lights on the degree of cure of orthodontic adhesives. Am J Orthod Dentofacial Orthop. 2007;132(3):382-4.\u003c/li\u003e\n\u003cli\u003eDewaele M, Asmussen E, Peutzfeldt A, Munksgaard EC, Benetti AR, Finn\u0026eacute; G, et al. Influence of curing protocol on selected properties of light-curing polymers: degree of conversion, volume contraction, elastic modulus, and glass transition temperature. Dent Mater. 2009;25(12):1576-84.\u003c/li\u003e\n\u003cli\u003eYoshida S, Namura Y, Matsuda M, Saito A, Shimizu N. Influence of light dose on bond strength of orthodontic light-cured adhesives. Eur J Orthod. 2012;34(4):493-7.\u003c/li\u003e\n\u003cli\u003eReynolds IRJBJoO. A Review of Direct Orthodontic Bonding. 1975;2(3):171-8.\u003c/li\u003e\n\u003cli\u003eR\u0026uuml;ger D, Harzer W, Krisjane Z, Tausche E. Shear bond strength after multiple bracket bonding with or without repeated etching. Eur J Orthod. 2011;33(5):521-7.\u003c/li\u003e\n\u003cli\u003eLee HM, Kim SC, Kang KH, Chang NY. Comparison of the bonding strengths of second- and third-generation light-emitting diode light-curing units. Korean J Orthod. 2016;46(6):364-71.\u003c/li\u003e\n\u003cli\u003eMohammed RE, Abass S, Abubakr NH, Mohammed ZM. Comparing orthodontic bond failures of light-cured composite resin with chemical-cured composite resin: A 12-month clinical trial. Am J Orthod Dentofacial Orthop. 2016;150(2):290-4.\u003c/li\u003e\n\u003cli\u003eOrganization IS. Dental Materials-Testing of adhesion to tooth structure. ISO/TS 11405, 1-16. Geneva, Switzerland: ISO. 2003.\u003c/li\u003e\n\u003cli\u003eBishara SE, Trulove TS. Comparisons of different debonding techniques for ceramic brackets: an in vitro study. Part II. Findings and clinical implications. Am J Orthod Dentofacial Orthop. 1990;98(3):263-73.\u003c/li\u003e\n\u003cli\u003eV\u0026auml;kiparta M, Puska M, Vallittu PK. Residual monomers and degree of conversion of partially bioresorbable fiber-reinforced composite. Acta Biomater. 2006;2(1):29-37.\u003c/li\u003e\n\u003cli\u003eVerma P. Curing efficiency of three light emitting diode units at different curing profiles. Indian J Dent Res. 2016;27(2):168-73.\u003c/li\u003e\n\u003cli\u003eOz AA, Oz AZ, Arici S. In-vitro bond strengths and clinical failure rates of metal brackets bonded with different light-emitting diode units and curing times. Am J Orthod Dentofacial Orthop. 2016;149(2):212-6.\u003c/li\u003e\n\u003cli\u003eKlocke A, Shi J, Vaziri F, Kahl-Nieke B, Bismayer U. Effect of time on bond strength in indirect bonding. Angle Orthod. 2004;74(2):245-50.\u003c/li\u003e\n\u003cli\u003eSwanson T, Dunn WJ, Childers DE, Taloumis LJ. Shear bond strength of orthodontic brackets bonded with light-emitting diode curing units at various polymerization times. Am J Orthod Dentofacial Orthop. 2004;125(3):337-41.\u003c/li\u003e\n\u003cli\u003eLi J. Effect of flexural strength of orthodontic resin cement on bond strength of metal brackets to enamel surfaces. Eur J Orthod. 2011;33(2):167-73.\u003c/li\u003e\n\u003cli\u003eAmato P, Martins L, Gatti A, Pretel H, Martins R. Influence of different wavelengths peaks in LED units on the degree of conversion of orthodontic composites. Journal of the World Federation of Orthodontists. 2016;5:118-21.\u003c/li\u003e\n\u003cli\u003ePeutzfeldt A, Asmussen E. Resin composite properties and energy density of light cure. J Dent Res. 2005;84(7):659-62.\u003c/li\u003e\n\u003cli\u003eDall\u0026apos;Igna CM, Marchioro EM, Spohr AM, Mota EG. Effect of curing time on the bond strength of a bracket-bonding system cured with a light-emitting diode or plasma arc light. Eur J Orthod. 2011;33(1):55-9.\u003c/li\u003e\n\u003cli\u003eLandis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159-74.\u003c/li\u003e\n\u003cli\u003eR\u0026uuml;ttermann S, Braun A, Janda R. Shear bond strength and fracture analysis of human vs. bovine teeth. PLoS One. 2013;8(3):e59181.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"clinical-oral-investigations","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cloi","sideBox":"Learn more about [Clinical Oral Investigations](http://link.springer.com/journal/784)","snPcode":"784","submissionUrl":"https://submission.nature.com/new-submission/784/3","title":"Clinical Oral Investigations","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"orthodontic brackets, spectroscopy, fourier transform infrared, shear strength","lastPublishedDoi":"10.21203/rs.3.rs-3973509/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3973509/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ewas to evaluate the effect of different photoactivation protocols of a high-power photo activator on the shear bond strength (SBS) between metal brackets and dental enamel and on the degree of conversion (DC) of an orthodontic resin.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterial and Methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e40 bovine incisor crowns were randomly assigned to 4 groups (n = 10). The brackets were bonded with Transbond XT® resin using 4 protocols according to the “photoactivation protocol” factor which was subdivided into: photoactivated faces and photoactivation time. All the samples were stored for 4 months (water,37ºC) and then subjected to a SBS test (100KgF,1mm/min). 40 resin discs were made to evaluate the monomer degree of conversion. Data from the SBS and DC were assessed by One-way ANOVA and Tukey’s test (5%). Bond failures were analyzed according to the Adhesive Remnant Index (ARI) and evaluated by the Kruskal-Wallis test (5%).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOne protocol showed a clinically acceptable SBS value. There was a statistically significant difference (p = 0.008) in the One-way ANOVA result for SBS values, but the protocols showed statistically similar results (p ≥ 0.05–Tukey’s tests) concerning the photoactivated faces and photoactivation time factors individually. There was no statistically significant difference (p ≥ 0.05) in the One-way ANOVA result for DC values.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe SBS and DC values will vary depending on the protocol applied and 6 seconds-centered activation seems to be the most suitable for clinical practice.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Relevance\u003c/strong\u003e: It is possible to maintain the bracket fixation quality with the use of a high-power LED photo activator associated with a shorter photoactivation time.\u003c/p\u003e","manuscriptTitle":"Effect of Time and Photoactivated Face on Bond Strength of Brackets and on Degree of Monomer Conversion","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-02-26 06:46:55","doi":"10.21203/rs.3.rs-3973509/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-03-21T21:27:35+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-03-21T21:04:09+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"802833f6-89c4-442f-9b39-a443aaa649c6","date":"2024-03-21T10:42:16+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-03-20T13:53:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"23af3713-5231-4208-95c8-ef7cf73f429e","date":"2024-02-28T11:37:22+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-02-28T09:53:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-02-22T12:52:36+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-02-22T12:52:36+00:00","index":"","fulltext":""},{"type":"submitted","content":"Clinical Oral Investigations","date":"2024-02-20T18:00:54+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"clinical-oral-investigations","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cloi","sideBox":"Learn more about [Clinical Oral Investigations](http://link.springer.com/journal/784)","snPcode":"784","submissionUrl":"https://submission.nature.com/new-submission/784/3","title":"Clinical Oral Investigations","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"085b508e-a650-4657-9dac-99883e9ed178","owner":[],"postedDate":"February 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-08-12T16:06:14+00:00","versionOfRecord":{"articleIdentity":"rs-3973509","link":"https://doi.org/10.1007/s00784-024-05854-5","journal":{"identity":"clinical-oral-investigations","isVorOnly":false,"title":"Clinical Oral Investigations"},"publishedOn":"2024-08-05 15:58:06","publishedOnDateReadable":"August 5th, 2024"},"versionCreatedAt":"2024-02-26 06:46:55","video":"","vorDoi":"10.1007/s00784-024-05854-5","vorDoiUrl":"https://doi.org/10.1007/s00784-024-05854-5","workflowStages":[]},"version":"v1","identity":"rs-3973509","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3973509","identity":"rs-3973509","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}