Assessment of the Relationship Between Labial Gingival Thickness and Underlying Bone Thickness in Maxillary Anterior Teeth by Two Digital Techniques

Assessment of the Relationship Between Labial Gingival Thickness and Underlying Bone Thickness in Maxillary Anterior Teeth by Two Digital Techniques | 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 Assessment of the Relationship Between Labial Gingival Thickness and Underlying Bone Thickness in Maxillary Anterior Teeth by Two Digital Techniques Linhong Wang, Jianping Chen, Yan Ruan, Yunxiao Luo, Fan Yang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-729394/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Jan, 2022 Read the published version in Scientific Reports → Version 1 posted 8 You are reading this latest preprint version Abstract The aim of this study is to noninvasively assess the relationship between the labial gingival thickness (GT) and the underlying bone thickness (BT) of the maxillary anterior teeth by two digital techniques. GT and BT were measured at 2、4 and 6 mm apical to the cemento-enamel junction (CEJ) by two digital techniques: M1- cone-beam computed tomography (CBCT) and M2- digital intraoral scanning (DIS) combined with CBCT (30 healthy participants, 172 maxillary anterior teeth). Pearson's correlation coefficient was calculated to assess the correlation between GT and BT. A significant negative correlation was identified between GT and BT at 2、4 mm apical to the CEJ for central incisors (CI), lateral incisors (LI), and canines (CA) both by M1 and M2, but not at 4 mm apical to the CEJ for CA (M2) or at 6 mm apical to the CEJ for all (M1, M2). The labial BT was demonstrated < 1 mm in most cases (85% of the CI; 97% of the LI; and 90% of the CA). Within the limitation of this study, it is concluded that the GT and BT seems to be negatively correlated in most cases, which should be cautious clinically. Dentistry gingival thickness (GT) bone thickness (BT) digital intraoral scanning CBCT Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Introduction Gingival biotype (GB) is closely associated with the long and short term esthetic outcomes of implant placement, restorative treatments, periodontal therapy in the esthetic region of the anterior maxilla, especially in the cases of immediate implantation, the implant is required to be placed in the ideal three-dimensional position with a thick GB and a thick labial bone plate 1 , a complete labial bone plate with a thickness at least 1–2 mm is necessary to prevent bone resorption on the labial side of the implant 2 , 3 , as well as to ensure the implants stability and long-term esthetic outcome of the soft tissue. Moreover, the thickness of gingiva is another factor affecting the long-term outcome of anterior esthetic effect 4 , 5 . Compared with thick GB, patients with a thin GB are more likely to have gingiva recession and alveolar bone retraction after implantation, which is associated with a high risk of esthetics 6 . Gingival thickness (GT) and the underlying alveolar bone thickness (BT) in esthetic zone seem to play a decisive role in the treatment outcomes. Accurate measurement of GT and the underlying BT before implant placement is beneficial to prevent complications such as soft tissue recession, implant exposure 7 , 8 . However, limited information is available regarding the relationship between the labial BT and GT due to the lack of a standardized measurement technique for measuring the thickness of hard and soft tissue at the same site 9 , there are relatively few studies on this issue and whether GT is specifically correlated with the thickness of the labial bone is still controversial and no consensus has been reached 10 , 11 . There are many methods to measure GB, GT and BT, such as the transgingival probing with periodontal probe 10 , 12 , which observe GB by the outline of the periodontal probe through the soft tissue. However, reports on the accuracy of this method disagree with different studies 10 – 12 . For GT, such as the direct puncture method which requires local anesthesia and is invasive 13 , the ultrasonic detection method which is non-invasive but its accuracy is limited for determining GT in some regions of the posterior teeth 14 . The cone beam computed tomography (CBCT) is an objective method for determining the thickness of soft and hard tissue 15 , some literature have indicated that CBCT has high precision in measuring BT 16 , 17 , but its low resolution and contrast limit its visualization on soft tissue 11,18−20 . The limitations of the above methods for measuring GT and BT warrant further studies in this area. Digital intraoral scanners (DIS) enabled the acquisition of data directly from the oral cavity and has been widely used in dentistry 21 . DIS images with more accurate outlines and greater resolution compared with CBCT was applied to measure the volume of periodontal tissues 22 , and has been demonstrated the higher precision and more reliability 23 . DIS improves the reproducibility and reduces the variance in measurements between different investigators. Several studies showed the accuracy of DIS on single elements or part of the arch commonly used in restorative or prosthodontic dentistry, such as crowns, inlays, onlays, and short bridges 24 – 28 , while the accuracy of DIS in multiple units or the full arch is still controversial 29 . The precision was clinically acceptable when scanning less than half of the arch 30 . Moreover, no consensus on the accuracy of DIS for soft tissue has been reached so far 31 , 32 . The DIS data can be combined with CBCT data. Whether the measurement of GT and BT on the superimposed data generated by CBCT data and DIS data will be more precise is still unknown. It is also necessary to establish a better understanding of the correlation between GT and BT. The purpose of this study is to analyze the correlation between the thickness of gingiva and the thickness of the underlying bone in the aesthetic area of maxillary anterior teeth through two digital techniques: CBCT (M1) and DIS combined with CBCT data (M2), and to provide a theoretical basis for the clinical selection of the aesthetic restoration, implant treatment in clinical practice. Materials And Methods Sample Selection Thirty medical students (18 males and 12 females) aged 20 to 26 years in Zhejiang Provincial People’s Hospital were enrolled in this study. Informed consent was obtained from the participants, and this study was approved by the Ethics Committee of Zhejiang Provincial People’s Hospital (2018KY015), which was performed according to the principles of the Declaration of Helsinki. Inclusion criteria: all subjects had a healthy periodontal condition with a periodontal probing depth of no more than 3 mm, a bleeding index of ≤ 2 (according to the bleeding index standard proposed by Mazza in 1981), and no gingiva recession in maxillary anterior teeth. Exclusion criteria: pregnant or lactating females; fillings or crowns in the maxillary anterior dentition; tooth malocclusion; use of any medication affecting the soft tissue; cigarette smoking; and a history of orthodontic therapy. Each subject was given instructions on maintaining oral hygiene and had their teeth cleaned one week before the test. In result, 172 teeth were included in the study (4 CIs, 4 LIs were excluded because of caries, periapical disease, torsional teeth). Method 1 (M1): CBCT measurements GT and BT was assessed using CBCT (Planmeca ProMax 3D and Helsinki, Finland) by one experienced dental radiologist and before scanning the lips and cheeks were retracted by a sterile plastic retractor. All scans were performed at 80 kV and 6.0 mA for 15 seconds (voxel size: 0.15 mm; gray scale: 15 bits; focal spot: 0.5 mm; and field of view: 12 x 9 cm). Image reconstruction for visual analysis was performed using the Romexis software (Romexis Viewer 3.5.1R, Planmeca, Helsinki, Finland). Measurements of the labial BT and GT for each tooth were performed at 2, 4, 6 mm apical to the CEJ on the mid-labial aspect perpendicular to the axis of the tooth in the sagittal plane (Fig. 1). All sites were measured by the same clinician. To assess intra-examiner reliability, duplicate registration was performed by the two examiners at an interval of 24 hours. Method 2 (M2): DIS+CBCT measurements GT and BT were assessed after registration between oral soft tissue images obtained by DIS and hard tissue images generated by CBCT. The teeth and gingival surfaces were cleaned and dried before intraoral scanning. The complete maxillary dentition, the labial and palatal gingival tissue were scanned by an experienced technician using the Trios intraoral scanner (3Shape Trios ®, Copenhagen, Denmark). The DIS data were exported into stereolithography (STL) format and matched with the CBCT data. Three highly radiopaque and relatively stable positions in the teeth were chosen as fiducial markers and were used as references to match the STL files with the CBCT images(acquired in M1) according to a best-fit algorithm using TRIOS software (3Shape Trios®, Implant Studio, Copenhagen, Denmark). The outline of the soft tissue on the labial side was visible as a yellow line. GT is defined as the distance from the surface of the gingiva to the surface of the alveolar bone or the surface of the tooth (Fig. 2-5). Measurements of labial GT and BT were performed at 2 mm, 4 mm, 6 mm apical to the CEJ at the mid-buccal aspect of each single rooted tooth, perpendicular to the axis of the tooth (L). Distance from CEJ to the alveolar bone crest (BC) was also obtained (BC-CEJ) (Fig 1, Fig 5). All sites were measured by the same clinician. To assess intra-examiner reliability, duplicate registration was performed by the two examiners at an interval of 24 hours. Statistical analysis The data were analyzed using SPSS 22.0 (SPSS Inc, Chicago, IL, USA). Quantitative data was presented as the means and standard deviations (SDs), and the normality of the data distribution was assessed by one-way variance analysis. The Friedman test was applied to compare the mean BT and GT between the three tooth types CI、LI、CA. If a significant difference was observed, each tooth types were compared using the Nemenyi post-hoc test. Pearson's correlation coefficient was applied to measure the correlation between the mean GT and BT between each teeth type. P < 0.05 was considered statistically significant. Results 172 anterior teeth of 30 participants with a mean age of 24 years was included. Two sets of recordings for M1 and M2 measurement of GT and BT were performed by two examiners at an interval of 24 hours to achieve intra-examiner reliability. Duplicate recordings of GT (0.875, 0.91 respectively; P < 0.001) and BT (0.812, 0.846 respectively; P < 0.05) demonstrated perfect agreement between different examiners. Therefore, the values measured by one of the examiners were used for further statistical analysis. 1 、 The correlation between BT and GT measured by M1 The results of correlation between BT and GT measured by M1 were shown in Table 1. In 172 anterior teeth, the mean thickness of underlying labial bone at the CI, LI, and CA was 0.74mm, 0.54mm, and 0.70 mm, respectively, and the mean corresponding GT was 1.14 mm, 1.00 mm, 0.94 mm respectively. There was a strong negative correlation between BT and GT at 2 mm, 4 mm apical to the CEJ in all maxillary anterior teeth, no correlation was found between BT and GT at 6mm apical to the CEJ in this three teeth types. 2 、 The correlation between BT and GT measured by M2 The results of correlation between BT and GT measured by M2 were shown in Table 2. The mean GT of the CI, LI, and CA was 0.98 mm, 0.88 mm, 0.83 mm and the underlying BT was 0.65 mm, 0.50 mm, 0.60 mm respectively. There was a strong negative correlation between BT and GT at 2 mm apical to the CEJ in this three teeth types, a weak negative correlation between BT and GT at 4 mm apical to the CEJ in CI, LI. No correlation between BT and GT at 4 mm apical to the CEJ in CA and 6 mm apical to the CEJ in this three teeth types. 3 、 Comparison of buccal bone and gingival thickness with respect to tooth type There was a significant difference in the mean thickness of buccal bone in the studied teeth in M1(P=0.009) and M2 (P=0.030). The BT of the CI was greater than that of LI and CA. Concerning GT, a difference was also found among tooth types (P=0.008, 0.016 respectively) and the thinnest was observed in the CA. (Table 3). 4 、 Distribution frequency of the labial BT and GT at different dental positions and different sites in M2 Analysis of the distribution frequency of labial BT measurements at 2, 4, 6 mm apical to the CEJ of the three types tooth was shown in Fig. 6-11. For the CI, 20 (11.63%) sites had a thickness less than 0.5 mm, 142 (82.56%) sites had a thickness of 0.5-1 mm, 6 (3.43%) sites had a thickness of 1.0-1.5 mm, and no sites had a thickness more than 1.5 mm. At the LI, 91 (52.91%) sites were 0.5-1.0 mm, and 4 (2.33%) sites were 1.0-1.5 mm. A total of 73 (42.44%) sites had a thickness less than 0.5 mm, no sites exhibited a thickness of 1.5 mm or more. For the CA, 163 (90.56%) sites were less than 1.0 mm thick, 14 (7.78%) sites were 1.0-1.5 mm thick, and only 3 (1.67%) sites more than 1.5 mm thick were detected. As for the GT，at the CI，90 (52.33%) sites had a thickness less than 1.0 mm, 66 (38.37%) sites had a thickness of 1.0-1.5 mm, 12 (6.98%) sites had a thickness greater than 1.5 mm. At the LI, 120 (69.77%) sites had a thickness less than 1.0 mm, and 40 (23.26%) sites were 1.0-1.5 mm thick. A total of 8 (4.65%) sites had a thickness greater than 1.5 mm. For the CA, 132 (73.33%) sites were less than 1.0 mm, 44 (24.44%) sites were 1.0-1.5 mm, and 4 (2.22%) sites more than 1.5 mm were detected. Discussion 1. Correlation between GT and BT The correlation between labial GT and BT in the maxillary anterior region were evaluated in the present study. No correlation was found between BT and GT at either 6 mm or 4 mm apical to the CEJ using M2 method, while there was a significantly negative correlation between BT and GT at other sites. This finding was consistent with the result of some other researchers such as Cao et al. who used a new method of CBCT combined with indirect gingival imaging to analyze the relationship between labial soft and hard tissues of the maxillary anterior teeth. Their study reported that GT at the site 2 mm below the labial central alveolar ridge in the upper anterior region was negatively correlated with BT 20 . Stein et al. also found the negative correlation between BT and GT in the proximal labial side of the maxillary anterior teeth using the transparency method with a gingival marginal periodontal probe 11 . However, Fu et al. measured the thickness of soft and hard tissue among the maxillary anterior teeth (2 mm apical to the alveolar crest) using both a caliper and an imaging method, in contrast, they found a positive correlation between the thickness of soft tissue and the thickness of the underlying bone 6 . This disagreement among different researchers highlights the controversy correlation between the thicknesses of soft and hard tissues commonly exist and used in preoperative planning. Some reports speculate this inconsistency among different research may be related with different measurement methods, different phenotype in the ethnicity of patients, and differences in measuring position 6,11,20 . However, the results of this study further suggest that the clinical evaluation of esthetic areas is complex for implantation timing (either immediate, early, or delayed) and for indications of aesthetic risk (such as gingiva recession or detachment). Furthermore, individual methods of judging soft tissue biotype for aesthetic risk using only the naked eye are unreliable. Many studies have found that GB is a comprehensive result of several factors not only the thickness of the gingiva, but also such as the thickness of the underlying bone, the dimensions of the dentogingival complex, the morphology of crown, the bone crest of cemento-enamel junction and so on 9,10,33,34 . GT in conjunction with the underlying BT showed the highest correlation with GB. The standard method for determining GT is transparency probing by a periodontal probe. However, the assessment of GB must also take into account other factors, such as the shape of the underlying bone and the size of the teeth. Furthermore, the GT can decrease due to age and other factors, and is the main cause of periodontal detachment and gingiva retraction 35 . Previous studies have shown that the risk of gingiva retraction in patients with a thin GB was significantly higher than in patients with a thick GB in periodontal and implantation treatments 36 , and moreover, GB can be changed through surgical techniques to augment soft tissue such as gingiva grafting or sub-epithelial connective tissue grafting 37,38 . Due to the mentioned inconsistencies on the determination of GB, clinical evaluations for indications of immediate implantation cannot solely rely on transparency probing technique. Eghbali et al. discussed the unreliability of visual examination for determining GB, the study revealed that roughly half of the participating patients with thin gingiva had been mistakenly classified as other biotype 39 . Kan et al. used calipers to directly measure GT at the point 2 mm under the middle margin of the extraction sockets, the result showed that gingiva 1 mm was defined as thick biotype 10 . Claffey et al. measured GT at the point 2 mm submarginal by puncture and subsequently proposed that 1.5mm would suffice as a maximal value for the thin biotype while gingiva >2 mm should be designated as a thick GB 40 . In this study, we found significant differences between GT measured by CBCT imaging alone and CBCT imaging matched with DIS, strongly suggesting that assessments of GB for clinical procedures should be more cautious. 2. Frequency distribution of buccal bone and gingival thickness Our results showed that the average thickness of the labial gingiva of the CI was 0.98 mm, and the average BT was 0.75 mm. The average thickness of labial gingiva of the LI was 0.88 mm, and the thickness of bone was 0.54 mm. The mean thickness of CA labial gingiva was 0.84 mm, and the thickness of the bone was 0.69 mm. In general, the proportion of GT > 1.5 mm was 7.1% for CI, 4.8% for LI, and 2.2% for CA. The proportion of BT for maxillary anterior teeth >1 mm was also significantly less, with proportions of the thick biotype for the CI, LI, CA of 3.3%, 2%, and 9%, respectively. The proportion of people who actually meet the criteria indicating for implantation of in the esthetic area is very rare, according to Buser et al. 1 . Clinical recommendations of immediate implantation of anterior teeth should be made with great caution. Nevertheless, this study found significant correlations between GT and BT at different sites in the anterior tooth region. Most notably, there was a significant negative correlation between the thickness of gingiva and the thickness of bone wall at 2 mm and 4 mm below the boundary between enamel and dentin bone. Therefore, when evaluating the esthetic risks prior to implantation or in anterior regions, it will be ill-advised to justify that a thick GB is necessarily corresponds to a thick gingiva and a thick bone plate, since this often leads to incorrect clinical decisions. Conclusions The current study demonstrated that there was a negative correlation between labial GT and BT in the anterior region. A thin labial BT and GT(< 1 mm) may be expected in over half of the maxillary anterior teeth. It should be aware that the thick gingiva is not related with the thick underlying bone plate in clinical practice. Declarations Acknowledgements This study was supported by Zhejiang Provincial Natural Science Foundation of China under Grant No. LGF20H140010 and Zhejiang Provincial Traditional Chinese Medicine Science and Technology Foundation of China under Grant No.2019ZA014. Author contributions L.W: Study design, clinical procedures, data analysis, interpretation of results, drafting and writing of the final article J.C: Clinical procedures, data acquisition, data analysis, prepared figures, approving final article Y.R: Statistical analysis, approving final article Y.L: Statistical analysis, approving final article F.Y: Study design, clinical procedures, interpretation of results, drafting and approving of the final article. All authors reviewed the manuscript. Competing interests The authors declare no competing interests. Additional information Correspondence and requests for materials should be addressed to F.Y. References Buser, D., Martin, W. & Belser, U. C. Optimizing Esthetics for Implant Restorations in the Anterior Maxilla: Anatomic and Surgical Considerations. Int J Oral Maxillofac Implants . 19 Suppl , 43-61.(2004). Grunder, U., Gracis, S. & Capelli, M. Influence of the 3-D Bone-To-Implant Relationship On Esthetics. 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The Gingival Biotype Assessed by Experienced and Inexperienced Clinicians. J. Clin. Periodontol. 36 , 958-963. https://10.1111/j.1600-051X.2009.01479.x (2009). Claffey, N. & Shanley, D. Relationship of Gingival Thickness and Bleeding to Loss of Probing Attachment in Shallow Sites Following Nonsurgical Periodontal Therapy. J. Clin. Periodontol. 13 , 654-657. https://10.1111/j.1600-051x.1986.tb00861.x (1986). Tables Table 1. Gingival thickness (GT) and bone thickness (BT) at 2, 4, and 6 mm apical to the CEJ by M1 Level Central incisors(CI) Lateral incisors(LI) Canines(CA) At 2 mm below the CEJ GT (mm) 1.26±0.37 1.02±0.37 1.13±0.42 BT (mm) 0.54±0.39 0.44±0.38 0.42±0.45 Pearson correlation -0.728 ** -0.767 ** -0.698 ** At 4 mm below the CEJ GT (mm) 1.03±0.27 0.90±0.36 0.92±0.37 BT (mm) 0.93±0.19 0.78±0.31 0.82±0.36 Pearson correlation -0.286 * -0.298 * -0.282 * At 6 mm below the CEJ GT (mm) 1.15±0.45 1.10±0.34 0.88±0.37 BT (mm) 0.77±0.25 0.41±0.38 0.73±0.37 Pearson correlation 0.036 -0.079 -0.066 **Confidence levels (bilateral) of < 0.01 indicate a significant correlation; *Confidence levels (bilateral) <0.05 indicate a significant correlation. Table 2. GT and BT at 2, 4, and 6 mm apical to the CEJ measured by M2 Level Central incisors(CI) Lateral incisors(LI) Canines(CA) At 2 mm below the CEJ GT (mm) 1.10±0.29 0.92±0.32 0.94±0.31 At 2 mm below the CEJ BT (mm) 0.52±0.27 0.41±0.30 0.42±0.40 Pearson correlation -0.707 ** -0.768 ** -0.585 ** GT (mm) 0.86±0.22 0.76±0.26 0.78±0.22 At 4 mm below the CEJ BT (mm) 0.76±0.14 0.66±0.22 0.73±0.32 Pearson correlation -0.319 * -0.292 * -0.197 GT (mm) 0.98±0.37 0.97±0.31 0.82±0.23 At 6 mm below the CEJ BT (mm) 0.66±0.13 0.37±0.25 0.59±0.32 Pearson correlation 0.000 0.163 0.202 **Confidence levels (bilateral) of < 0.01 indicate a significant correlation; *Confidence levels (bilateral) <0.05 indicate a significant correlation. Table 3. The mean±standard deviation of GT and BT (mm) in maxillary anterior teeth Tooth types M1 M2 GT BT GT BT CI (mm) 1.14±0.36 0.74±0.28 0.98±0.29 0.65±0.18 LI (mm) 1.00±0.36 0.54±0.36 0.88±0.29 0.50±0.25 CA (mm) 0.94±0.38 0.70±0.40 0.83±0.24 0.60±0.34 P-value 0.009 0.008 0.030 0.016 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 13 Jan, 2022 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Major revision 15 Oct, 2021 Reviews received at journal 01 Oct, 2021 Reviewers agreed at journal 22 Sep, 2021 Reviewers invited by journal 02 Aug, 2021 Editor assigned by journal 02 Aug, 2021 Editor invited by journal 21 Jul, 2021 Submission checks completed at journal 21 Jul, 2021 First submitted to journal 18 Jul, 2021 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-729394","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":40840872,"identity":"ff1ade0a-1364-44de-ab14-c19f342ddb33","order_by":0,"name":"Linhong Wang","email":"","orcid":"","institution":"Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College","correspondingAuthor":false,"prefix":"","firstName":"Linhong","middleName":"","lastName":"Wang","suffix":""},{"id":40840873,"identity":"4535516c-ecf7-480e-a411-f7953eabad36","order_by":1,"name":"Jianping Chen","email":"","orcid":"","institution":"Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College","correspondingAuthor":false,"prefix":"","firstName":"Jianping","middleName":"","lastName":"Chen","suffix":""},{"id":40840874,"identity":"31e76817-776d-40d8-a2c8-b1aa5cb2c41b","order_by":2,"name":"Yan Ruan","email":"","orcid":"","institution":"Bengbu Medical College","correspondingAuthor":false,"prefix":"","firstName":"Yan","middleName":"","lastName":"Ruan","suffix":""},{"id":40840875,"identity":"956529e7-1f1a-4c84-bd4a-2253fa0e6b5b","order_by":3,"name":"Yunxiao Luo","email":"","orcid":"","institution":"Zhejiang Chinese Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yunxiao","middleName":"","lastName":"Luo","suffix":""},{"id":40840876,"identity":"73ea9d13-0c4e-4598-9461-54db24f4cddb","order_by":4,"name":"Fan Yang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1klEQVRIiWNgGAWjYLCCCgYGOQMwi41YLWcYGIxJ15K4gWgtBsfPHn5xoOZO+naxww8YPpQdZuCf3UBAy5m8NIsDx57l7pydZsA449xhBok7BwhoOZBjZvyB7XDuhts5DMy8bYcZDCQSCGg5/8bM4MC/w+kGIC1/idJyI8f4wcG2wwlgLYzEaJG88caM4WDfYcMNt9MMDvacS+eRuEFAC9/5HOMPB74dlje4nfzwwY8yazn+GQS0KBxgYJOAcQ4AMQ9+9UAg38DA/IGgqlEwCkbBKBjZAABm2EzSVfUNEgAAAABJRU5ErkJggg==","orcid":"","institution":"Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College","correspondingAuthor":true,"prefix":"","firstName":"Fan","middleName":"","lastName":"Yang","suffix":""}],"badges":[],"createdAt":"2021-07-18 06:59:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-729394/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-729394/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-021-04721-7","type":"published","date":"2022-01-13T12:24:26+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":11756742,"identity":"a13aab1d-8ee0-4e65-a33e-76a98931e6a2","added_by":"auto","created_at":"2021-07-23 22:25:38","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":41107,"visible":true,"origin":"","legend":"Measurements taken in the median sagittal plane of teeth in a simple CBCT image: distance from the bone crest to CEJ (BC-CEJ); gingival thickness (GT2, GT4, GT6) at 2, 4, and 6 mm apical to the CEJ; labial bone thickness (BT2, BT4, BT6) at 2, 4, and 6 mm apical to the CEJ.","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/974aa93800a914d553501ce5.png"},{"id":11756906,"identity":"fc0a01ab-d37c-4698-a8ed-db0fbf02573b","added_by":"auto","created_at":"2021-07-23 22:28:38","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":58345,"visible":true,"origin":"","legend":"Intraoral soft tissue images collected by 3-Shape Trios ® scanner.","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/968b2d482609839949975612.png"},{"id":11756732,"identity":"d7790c9d-93e0-459a-9b95-3b1c491a73e5","added_by":"auto","created_at":"2021-07-23 22:25:38","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":108349,"visible":true,"origin":"","legend":"Hard tissue images taken by CBCT.","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/f391f4bf5ab5ff1750411d9d.png"},{"id":11756733,"identity":"b3804f58-bd54-4cbd-b1fa-365cfd7f7491","added_by":"auto","created_at":"2021-07-23 22:25:38","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":111761,"visible":true,"origin":"","legend":"The soft and hard tissue images were registered, and measurements were taken along the median sagittal plane of the tooth, indicated by intercepted axis.","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/8613858d5c734987ffc8adca.png"},{"id":11756739,"identity":"c2b497c3-e4ba-4f2a-aa4a-b98bfc38b423","added_by":"auto","created_at":"2021-07-23 22:25:38","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":43325,"visible":true,"origin":"","legend":"The scanned gingival profile was automatically marked with a thin yellow line. Measurement of the distance from the bone crest to CEJ (BC-CEJ); gingival thickness (GT2, GT4, GT6) at 2, 4, and 6 mm apical to the CEJ; labial bone thickness (BT2, BT4, BT6) at 2, 4, and 6 mm apical to the CEJ.","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/b165b8da6dd021d11f6499e0.png"},{"id":11756734,"identity":"3befd861-f53e-4ae4-b670-aa97dba409bb","added_by":"auto","created_at":"2021-07-23 22:25:38","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":17222,"visible":true,"origin":"","legend":"Distribution frequency of bone thickness at different sites in the central incisor region.","description":"","filename":"Figure6.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/92c73013540c487f672a32d3.png"},{"id":11756737,"identity":"b1bfe5ad-2dcc-48e7-bb57-5322ef00deff","added_by":"auto","created_at":"2021-07-23 22:25:38","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":16933,"visible":true,"origin":"","legend":"Distribution frequency of bone thickness at different sites in the lateral incisor region. ","description":"","filename":"Figure7.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/55acfc3e9db3eaed75d213de.png"},{"id":11756905,"identity":"52ad8a1d-1c12-4671-8265-7097017af51f","added_by":"auto","created_at":"2021-07-23 22:28:38","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":17911,"visible":true,"origin":"","legend":"Distribution frequency of bone thickness at different sites in the canine region.","description":"","filename":"Figure8.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/f69987c807ba11a5c0c6aa19.png"},{"id":11756907,"identity":"558df99b-c449-489d-808b-e2369a6119df","added_by":"auto","created_at":"2021-07-23 22:28:38","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":18216,"visible":true,"origin":"","legend":"Distribution frequency of gingival thickness at different sites in the central incisor region.","description":"","filename":"Figure9.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/d9b632e0439b3e1b3f0a8c07.png"},{"id":11756741,"identity":"0e5b512f-d4ae-4a65-b227-9dbfe6934e9d","added_by":"auto","created_at":"2021-07-23 22:25:38","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":18226,"visible":true,"origin":"","legend":"Distribution frequency of gingival thickness at different sites in the lateral incisor region.","description":"","filename":"Figure10.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/f3fecb75c7795e7033a6b504.png"},{"id":11756736,"identity":"01430b72-f4f5-4b36-9671-bcde10524e96","added_by":"auto","created_at":"2021-07-23 22:25:38","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":18123,"visible":true,"origin":"","legend":"Distribution frequency of gingival thickness at different sites in the canine region.","description":"","filename":"Figure11.png","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/3c396026d1789c77aa511462.png"},{"id":17281000,"identity":"44d16e5a-224b-45f4-8ac0-863f4c1bee03","added_by":"auto","created_at":"2022-01-13 12:24:29","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":976681,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-729394/v1/2a2d358a-06a2-41f0-9d01-f72402833a13.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eAssessment of the Relationship Between Labial Gingival Thickness and Underlying Bone Thickness in Maxillary Anterior Teeth by Two Digital Techniques \u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGingival biotype (GB) is closely associated with the long and short term esthetic outcomes of implant placement, restorative treatments, periodontal therapy in the esthetic region of the anterior maxilla, especially in the cases of immediate implantation, the implant is required to be placed in the ideal three-dimensional position with a thick GB and a thick labial bone plate\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e, a complete labial bone plate with a thickness at least 1\u0026ndash;2 mm is necessary to prevent bone resorption on the labial side of the implant\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, as well as to ensure the implants stability and long-term esthetic outcome of the soft tissue. Moreover, the thickness of gingiva is another factor affecting the long-term outcome of anterior esthetic effect\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Compared with thick GB, patients with a thin GB are more likely to have gingiva recession and alveolar bone retraction after implantation, which is associated with a high risk of esthetics\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. Gingival thickness (GT) and the underlying alveolar bone thickness (BT) in esthetic zone seem to play a decisive role in the treatment outcomes.\u003c/p\u003e \u003cp\u003eAccurate measurement of GT and the underlying BT before implant placement is beneficial to prevent complications such as soft tissue recession, implant exposure\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. However, limited information is available regarding the relationship between the labial BT and GT due to the lack of a standardized measurement technique for measuring the thickness of hard and soft tissue at the same site\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, there are relatively few studies on this issue and whether GT is specifically correlated with the thickness of the labial bone is still controversial and no consensus has been reached\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. There are many methods to measure GB, GT and BT, such as the transgingival probing with periodontal probe\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e, which observe GB by the outline of the periodontal probe through the soft tissue. However, reports on the accuracy of this method disagree with different studies\u003csup\u003e\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. For GT, such as the direct puncture method which requires local anesthesia and is invasive\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e, the ultrasonic detection method which is non-invasive but its accuracy is limited for determining GT in some regions of the posterior teeth\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. The cone beam computed tomography (CBCT) is an objective method for determining the thickness of soft and hard tissue\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e, some literature have indicated that CBCT has high precision in measuring BT\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e, but its low resolution and contrast limit its visualization on soft tissue\u003csup\u003e11,18\u0026minus;20\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe limitations of the above methods for measuring GT and BT warrant further studies in this area. Digital intraoral scanners (DIS) enabled the acquisition of data directly from the oral cavity and has been widely used in dentistry\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. DIS images with more accurate outlines and greater resolution compared with CBCT was applied to measure the volume of periodontal tissues\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e, and has been demonstrated the higher precision and more reliability\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. DIS improves the reproducibility and reduces the variance in measurements between different investigators. Several studies showed the accuracy of DIS on single elements or part of the arch commonly used in restorative or prosthodontic dentistry, such as crowns, inlays, onlays, and short bridges\u003csup\u003e\u003cspan additionalcitationids=\"CR25 CR26 CR27\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e, while the accuracy of DIS in multiple units or the full arch is still controversial\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. The precision was clinically acceptable when scanning less than half of the arch\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. Moreover, no consensus on the accuracy of DIS for soft tissue has been reached so far\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e,\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. The DIS data can be combined with CBCT data. Whether the measurement of GT and BT on the superimposed data generated by CBCT data and DIS data will be more precise is still unknown.\u003c/p\u003e \u003cp\u003eIt is also necessary to establish a better understanding of the correlation between GT and BT. The purpose of this study is to analyze the correlation between the thickness of gingiva and the thickness of the underlying bone in the aesthetic area of maxillary anterior teeth through two digital techniques: CBCT (M1) and DIS combined with CBCT data (M2), and to provide a theoretical basis for the clinical selection of the aesthetic restoration, implant treatment in clinical practice.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cp\u003e\u003cstrong\u003eSample Selection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThirty medical students (18 males and 12 females) aged 20 to 26 years in Zhejiang Provincial People\u0026rsquo;s Hospital were enrolled in this study. Informed consent was obtained from the participants, and this study was approved by the Ethics Committee of Zhejiang Provincial People\u0026rsquo;s Hospital (2018KY015), which was performed according to the principles of the Declaration of Helsinki.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eInclusion criteria: all subjects had a healthy periodontal condition with a periodontal probing depth of no more than 3 mm, a bleeding index of \u0026le; 2 (according to the bleeding index standard proposed by Mazza in 1981), and no gingiva recession in maxillary anterior teeth. \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eExclusion criteria: pregnant or lactating females; fillings or crowns in the maxillary anterior dentition; tooth malocclusion; use of any medication affecting the soft tissue; cigarette smoking; and a history of orthodontic therapy. Each subject was given instructions on maintaining oral hygiene and had their teeth cleaned one week before the test. In result, 172 teeth were included in the study (4 CIs, 4 LIs were excluded because of caries, periapical disease, torsional teeth).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethod 1 (M1): CBCT measurements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGT and BT was assessed using CBCT (Planmeca ProMax 3D and Helsinki, Finland) by one experienced dental radiologist and before scanning the lips and cheeks were retracted by a sterile plastic retractor. All scans were performed at 80 kV and 6.0 mA for 15 seconds (voxel size: 0.15 mm; gray scale: 15 bits; focal spot: 0.5 mm; and field of view: 12 x 9 cm). Image reconstruction for visual analysis was performed using the Romexis software (Romexis Viewer 3.5.1R, Planmeca, Helsinki, Finland). Measurements of the labial BT and GT for each tooth were performed at 2, 4, 6 mm apical to the CEJ on the mid-labial aspect perpendicular to the axis of the tooth in the sagittal plane (Fig. 1). All sites were measured by the same clinician. To assess intra-examiner reliability, duplicate registration was performed by the two examiners at an interval of 24 hours.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethod 2 (M2): DIS+CBCT measurements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGT and BT were assessed after registration between oral soft tissue images obtained by DIS and hard tissue images generated by CBCT. The teeth and gingival surfaces were cleaned and dried before intraoral scanning. The complete maxillary dentition, the labial and palatal gingival tissue were scanned by an experienced technician using the Trios intraoral scanner (3Shape Trios \u0026reg;, Copenhagen, Denmark). The DIS data were exported into stereolithography (STL) format and matched with the CBCT data. Three highly radiopaque and relatively stable positions in the teeth were chosen as fiducial markers and were used as references to match the STL files with the CBCT images(acquired in M1) according to a best-fit algorithm using TRIOS software (3Shape Trios\u0026reg;, Implant Studio, Copenhagen, Denmark). The outline of the soft tissue on the labial side was visible as a yellow line. GT is defined as the distance from the surface of the gingiva to the surface of the alveolar bone or the surface of the tooth (Fig. 2-5).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMeasurements of labial GT and BT were performed at 2 mm, 4 mm, 6 mm apical to the CEJ at the mid-buccal aspect of each single rooted tooth, perpendicular to the axis of the tooth (L). Distance from CEJ to the alveolar bone crest (BC) was also obtained (BC-CEJ) (Fig 1, Fig 5). All sites were measured by the same clinician. To assess intra-examiner reliability, duplicate registration was performed by the two examiners at an interval of 24 hours.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data were analyzed using SPSS 22.0 (SPSS Inc, Chicago, IL, USA). Quantitative data was presented as the means and standard deviations (SDs), and the normality of the data distribution was assessed by one-way variance analysis. The Friedman test was applied to compare the mean BT and GT between the three tooth types CI、LI、CA. If a significant difference was observed, each tooth types were compared using the Nemenyi post-hoc test. Pearson\u0026apos;s correlation coefficient was applied to measure the correlation between the mean GT and BT between each teeth type. P \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e172 anterior teeth of 30 participants with a mean age of 24 years was included. Two sets of recordings for M1 and M2 measurement of GT and BT were performed by two examiners at an interval of 24 hours to achieve intra-examiner reliability. Duplicate recordings of GT (0.875, 0.91 respectively; P \u0026lt; 0.001) and BT (0.812, 0.846 respectively; P \u0026lt; 0.05) demonstrated perfect agreement between different examiners. Therefore, the values measured by one of the examiners were used for further statistical analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003cstrong\u003e、\u003c/strong\u003e\u003cstrong\u003eThe correlation between BT and GT measured by M1\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe results of correlation between BT and GT measured by M1 were shown in Table 1. In 172 anterior teeth, the mean thickness of underlying labial bone at the CI, LI, and CA was 0.74mm, 0.54mm, and 0.70 mm, respectively, and the mean corresponding GT was 1.14 mm, 1.00 mm, 0.94 mm respectively. There was a strong negative correlation between BT and GT at 2 mm, 4 mm apical to the CEJ in all maxillary anterior teeth, no correlation was found between BT and GT at 6mm apical to the CEJ in this three teeth types.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003cstrong\u003e、\u003c/strong\u003e\u003cstrong\u003eThe correlation between BT and GT measured by M2\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe results of correlation between BT and GT measured by M2 were shown in Table 2. The mean GT of the CI, LI, and CA was 0.98 mm, 0.88 mm, 0.83 mm and the underlying BT was 0.65 mm, 0.50 mm, 0.60 mm respectively. There was a strong negative correlation between BT and GT at 2 mm apical to the CEJ in this three teeth types, a weak negative correlation between BT and GT at 4 mm apical to the CEJ in CI, LI. No correlation between BT and GT at 4 mm apical to the CEJ in CA and 6 mm apical to the CEJ in this three teeth types.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003cstrong\u003e、\u003c/strong\u003e\u003cstrong\u003eComparison of buccal bone and gingival thickness with respect to tooth type\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere was a significant difference in the mean thickness of buccal bone in the studied teeth in M1(P=0.009) and M2 (P=0.030). The BT of the CI was greater than that of LI and CA. Concerning GT, a difference was also found among tooth types (P=0.008, 0.016 respectively) and the thinnest was observed in the CA. (Table 3).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003cstrong\u003e、\u003c/strong\u003e\u003cstrong\u003eDistribution frequency of the labial BT and GT at different dental positions and different sites in M2\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnalysis of the distribution frequency of labial BT measurements at 2, 4, 6 mm apical to the CEJ of the three types tooth was shown in Fig. 6-11. For the CI, 20 (11.63%) sites had a thickness less than 0.5 mm, 142 (82.56%) sites had a thickness of 0.5-1 mm, 6 (3.43%) sites had a thickness of 1.0-1.5 mm, and no sites had a thickness more than 1.5 mm. At the LI, 91 (52.91%) sites were 0.5-1.0 mm, and 4 (2.33%) sites were 1.0-1.5 mm. A total of 73 (42.44%) sites had a thickness less than 0.5 mm, no sites exhibited a thickness of 1.5 mm or more. For the CA, 163 (90.56%) sites were less than 1.0 mm thick, 14 (7.78%) sites were 1.0-1.5 mm thick, and only 3 (1.67%) sites more than 1.5 mm thick were detected.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAs for the GT，at the CI，90 (52.33%) sites had a thickness less than 1.0 mm, 66 (38.37%) sites had a thickness of 1.0-1.5 mm, 12 (6.98%) sites had a thickness greater than 1.5 mm. At the LI, 120 (69.77%) sites had a thickness less than 1.0 mm, and 40 (23.26%) sites were 1.0-1.5 mm thick. A total of 8 (4.65%) sites had a thickness greater than 1.5 mm. For the CA, 132 (73.33%) sites were less than 1.0 mm, 44 (24.44%) sites were 1.0-1.5 mm, and 4 (2.22%) sites more than 1.5 mm were detected.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003e\u003cstrong\u003e1. Correlation between GT and BT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe correlation between labial GT and BT in the maxillary anterior region were evaluated in the present study. No correlation was found between BT and GT at either 6 mm or 4 mm apical to the CEJ using M2 method, while there was a significantly negative correlation between BT and GT at other sites. This finding was consistent with the result of some other researchers such as Cao et al. who used a new method of CBCT combined with indirect gingival imaging to analyze the relationship between labial soft and hard tissues of the maxillary anterior teeth. Their study reported that GT at the site 2 mm below the labial central alveolar ridge in the upper anterior region was negatively correlated with BT\u003csup\u003e20\u003c/sup\u003e. Stein et al. also found the negative correlation between BT and GT in the proximal labial side of the maxillary anterior teeth using the transparency method with a gingival marginal periodontal probe\u003csup\u003e11\u003c/sup\u003e. However, Fu et al. measured the thickness of soft and hard tissue among the maxillary anterior teeth (2 mm apical to the alveolar crest) using both a caliper and an imaging method, in contrast, they found a positive correlation between the thickness of soft tissue and the thickness of the underlying bone\u003csup\u003e6\u003c/sup\u003e. This disagreement among different researchers highlights the controversy correlation between the thicknesses of soft and hard tissues commonly exist and used in preoperative planning. Some reports speculate this inconsistency among different research may be related with different measurement methods, different phenotype in the ethnicity of patients, and differences in measuring position\u003csup\u003e6,11,20\u003c/sup\u003e. However, the results of this study further suggest that the clinical evaluation of esthetic areas is complex for implantation timing (either immediate, early, or delayed) and for indications of aesthetic risk (such as gingiva recession or detachment). Furthermore, individual methods of judging soft tissue biotype for aesthetic risk using only the naked eye are unreliable.\u003c/p\u003e\n\u003cp\u003eMany studies have found that GB is a comprehensive result of several factors not only the thickness of the gingiva, but also such as the thickness of the underlying bone, the dimensions of the dentogingival complex, the morphology of crown, the bone crest of cemento-enamel junction and so on\u003csup\u003e9,10,33,34\u003c/sup\u003e. GT in conjunction with the underlying BT showed the highest correlation with GB. The standard method for determining GT is transparency probing by a periodontal probe. However, the assessment of GB must also take into account other factors, such as the shape of the underlying bone and the size of the teeth. Furthermore, the GT can decrease due to age and other factors, and is the main cause of periodontal detachment and gingiva retraction\u003csup\u003e35\u003c/sup\u003e. Previous studies have shown that the risk of gingiva retraction in patients with a thin GB was significantly higher than in patients with a thick GB in periodontal and implantation treatments\u003csup\u003e36\u003c/sup\u003e, and moreover, GB can be changed through surgical techniques to augment soft tissue such as gingiva grafting or sub-epithelial connective tissue grafting\u003csup\u003e37,38\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDue to the mentioned inconsistencies on the determination of GB, clinical evaluations for indications of immediate implantation cannot solely rely on transparency probing technique. Eghbali et al. discussed the unreliability of visual examination for determining GB, the study revealed that roughly half of the participating patients with thin gingiva had been mistakenly classified as other biotype\u003csup\u003e39\u003c/sup\u003e. Kan et al. used calipers to directly measure GT at the point 2 mm under the middle margin of the extraction sockets, the result showed that gingiva \u0026lt; 1 mm should be designated as the thin biotype, while \u0026gt;1 mm was defined as thick biotype\u003csup\u003e10\u003c/sup\u003e. Claffey et al. measured GT at the point 2 mm submarginal by puncture and subsequently proposed that 1.5mm would suffice as a maximal value for the thin biotype while gingiva \u0026gt;2 mm should be designated as a thick GB\u003csup\u003e40\u003c/sup\u003e. In this study, we found significant differences between GT measured by CBCT imaging alone and CBCT imaging matched with DIS, strongly suggesting that assessments of GB for clinical procedures should be more cautious.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Frequency distribution of buccal bone and gingival thickness\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOur results showed that the average thickness of the labial gingiva of the CI was 0.98 mm, and the average BT was 0.75 mm. The average thickness of labial gingiva of the LI was 0.88 mm, and the thickness of bone was 0.54 mm. The mean thickness of CA labial gingiva was 0.84 mm, and the thickness of the bone was 0.69 mm. In general, the proportion of GT \u0026gt; 1.5 mm was 7.1% for CI, 4.8% for LI, and 2.2% for CA. The proportion of BT for maxillary anterior teeth \u0026gt;1 mm was also significantly less, with proportions of the thick biotype for the CI, LI, CA of 3.3%, 2%, and 9%, respectively. The proportion of people who actually meet the criteria indicating for implantation of in the esthetic area is very rare, according to Buser et al.\u003csup\u003e1\u003c/sup\u003e. Clinical recommendations of immediate implantation of anterior teeth should be made with great caution. Nevertheless, this study found significant correlations between GT and BT at different sites in the anterior tooth region. Most notably, there was a significant negative correlation between the thickness of gingiva and the thickness of bone wall at 2 mm and 4 mm below the boundary between enamel and dentin bone. Therefore, when evaluating the esthetic risks prior to implantation or in anterior regions, it will be ill-advised to justify that a thick GB is necessarily corresponds to a thick gingiva and a thick bone plate, since this often leads to incorrect clinical decisions.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe current study demonstrated that there was a negative correlation between labial GT and BT in the anterior region. A thin labial BT and GT(\u0026lt;\u0026thinsp;1 mm) may be expected in over half of the maxillary anterior teeth. It should be aware that the thick gingiva is not related with the thick underlying bone plate in clinical practice.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by Zhejiang Provincial Natural Science Foundation of China under Grant No. LGF20H140010 and Zhejiang Provincial Traditional Chinese Medicine Science and Technology Foundation of China under Grant No.2019ZA014.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eL.W: Study design, clinical procedures, data analysis, interpretation of results, drafting and writing of the final article J.C: Clinical procedures, data acquisition, data analysis, prepared figures, approving final article Y.R: Statistical analysis, approving final article Y.L: Statistical analysis, approving final article F.Y: Study design, clinical procedures, interpretation of results, drafting and approving of the final article. All authors reviewed the manuscript. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional information \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCorrespondence and requests for materials should be addressed to F.Y.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBuser, D., Martin, W. \u0026amp; Belser, U. C. Optimizing Esthetics for Implant Restorations in the Anterior Maxilla: Anatomic and Surgical Considerations. \u003cem\u003eInt J Oral Maxillofac Implants\u003c/em\u003e. \u003cstrong\u003e19 Suppl\u003c/strong\u003e, 43-61.(2004).\u003c/li\u003e\n\u003cli\u003eGrunder, U., Gracis, S. \u0026amp; Capelli, M. 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Accuracy of Full-Arch Scans Using Intraoral Scanners. \u003cem\u003eClin Oral Investig\u003c/em\u003e. \u003cstrong\u003e18\u003c/strong\u003e, 1687-1694. https://10.1007/s00784-013-1132-y (2014).\u003c/li\u003e\n\u003cli\u003eSu, T. S. \u0026amp; Sun, J. Comparison of Repeatability Between Intraoral Digital Scanner and Extraoral Digital Scanner: An In-Vitro Study. \u003cem\u003eJ Prosthodont Res\u003c/em\u003e. \u003cstrong\u003e59\u003c/strong\u003e, 236-242. https://10.1016/j.jpor.2015.06.002 (2015).\u003c/li\u003e\n\u003cli\u003eMangano, F., Shibli, J. A. \u0026amp; Fortin, T. Digital Dentistry: New Materials and Techniques. \u003cem\u003eInt J Dent\u003c/em\u003e. \u003cstrong\u003e2016\u003c/strong\u003e, 5261247. https://10.1155/2016/5261247 (2016).\u003c/li\u003e\n\u003cli\u003eMangano, F., Gandolfi, A., Luongo, G. \u0026amp; Logozzo, S. Intraoral Scanners in Dentistry: A Review of the Current Literature. \u003cem\u003eBMC Oral Health\u003c/em\u003e. \u003cstrong\u003e17\u003c/strong\u003e, 149. https://10.1186/s12903-017-0442-x (2017).\u003c/li\u003e\n\u003cli\u003eNikiforidou, M., Tsalikis, L., Angelopoulos, C., Menexes, G., Vouros, I. \u0026amp; Konstantinides, A. Classification of Periodontal Biotypes with the Use of CBCT. A Cross-Sectional Study. \u003cem\u003eClin Oral Investig\u003c/em\u003e. \u003cstrong\u003e20\u003c/strong\u003e, 2061-2071. https://10.1007/s00784-015-1694-y (2016).\u003c/li\u003e\n\u003cli\u003eAmid, R., Mirakhori, M., Safi, Y., Kadkhodazadeh, M. \u0026amp; Namdari, M. Assessment of Gingival Biotype and Facial Hard/Soft Tissue Dimensions in the Maxillary Anterior Teeth Region Using Cone Beam Computed Tomography. \u003cem\u003eArch. Oral Biol.\u003c/em\u003e \u003cstrong\u003e79\u003c/strong\u003e, 1-6. https://10.1016/j.archoralbio.2017.02.021 (2017).\u003c/li\u003e\n\u003cli\u003eJanuario, A. L., Barriviera, M. \u0026amp; Duarte, W. R. Soft Tissue Cone-Beam Computed Tomography: A Novel Method for the Measurement of Gingival Tissue and the Dimensions of the Dentogingival Unit. \u003cem\u003eJ. Esthet. Restor. Dent.\u003c/em\u003e \u003cstrong\u003e20\u003c/strong\u003e, 366-373, 374. https://10.1111/j.1708-8240.2008.00210.x (2008).\u003c/li\u003e\n\u003cli\u003eKao, R. T. \u0026amp; Pasquinelli, K. Thick Vs. Thin Gingival Tissue: A Key Determinant in Tissue Response to Disease and Restorative Treatment. \u003cem\u003eJ Calif Dent Assoc\u003c/em\u003e. \u003cstrong\u003e30\u003c/strong\u003e, 521-526.(2002).\u003c/li\u003e\n\u003cli\u003eKuis, D., Sciran, I., Lajnert, V., Snjaric, D., Prpic, J., Pezelj-Ribaric, S. \u0026amp; Bosnjak, A. Coronally Advanced Flap Alone Or with Connective Tissue Graft in the Treatment of Single Gingival Recession Defects: A Long-Term Randomized Clinical Trial. \u003cem\u003eJ. Periodontol.\u003c/em\u003e \u003cstrong\u003e84\u003c/strong\u003e, 1576-1585. https://10.1902/jop.2013.120451 (2013).\u003c/li\u003e\n\u003cli\u003eCarnio, J., Camargo, P. M. \u0026amp; Pirih, P. Q. Surgical Techniques to Increase the Apicocoronal Dimension of the Attached Gingiva: A 1-Year Comparison Between the Free Gingival Graft and the Modified Apically Repositioned Flap. \u003cem\u003eInt J Periodontics Restorative Dent\u003c/em\u003e. \u003cstrong\u003e35\u003c/strong\u003e, 571-578. https://10.11607/prd.2386 (2015).\u003c/li\u003e\n\u003cli\u003eEghbali, A., De Rouck, T., De Bruyn, H. \u0026amp; Cosyn, J. The Gingival Biotype Assessed by Experienced and Inexperienced Clinicians. \u003cem\u003eJ. Clin. Periodontol.\u003c/em\u003e \u003cstrong\u003e36\u003c/strong\u003e, 958-963. https://10.1111/j.1600-051X.2009.01479.x (2009).\u003c/li\u003e\n\u003cli\u003eClaffey, N. \u0026amp; Shanley, D. Relationship of Gingival Thickness and Bleeding to Loss of Probing Attachment in Shallow Sites Following Nonsurgical Periodontal Therapy. \u003cem\u003eJ. Clin. Periodontol.\u003c/em\u003e \u003cstrong\u003e13\u003c/strong\u003e, 654-657. https://10.1111/j.1600-051x.1986.tb00861.x (1986).\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u0026nbsp;\u003c/strong\u003eGingival thickness (GT) and bone thickness (BT) at 2, 4, and 6 mm apical to the CEJ by M1 \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.29803328290469%\"\u003e\n \u003cp\u003eLevel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.15431164901664%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.667170953101362%\"\u003e\n \u003cp\u003eCentral incisors(CI)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.969742813918305%\"\u003e\n \u003cp\u003eLateral incisors(LI)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.910741301059%\"\u003e\n \u003cp\u003eCanines(CA)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" width=\"23.29803328290469%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAt 2 mm below the CEJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.15431164901664%\"\u003e\n \u003cp\u003eGT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.667170953101362%\"\u003e\n \u003cp\u003e1.26\u0026plusmn;0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.969742813918305%\"\u003e\n \u003cp\u003e1.02\u0026plusmn;0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.910741301059%\"\u003e\n \u003cp\u003e1.13\u0026plusmn;0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.668639053254438%\"\u003e\n \u003cp\u003eBT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.641025641025642%\"\u003e\n \u003cp\u003e0.54\u0026plusmn;0.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.035502958579883%\"\u003e\n \u003cp\u003e0.44\u0026plusmn;0.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"24.65483234714004%\"\u003e\n \u003cp\u003e0.42\u0026plusmn;0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.668639053254438%\"\u003e\n \u003cp\u003ePearson correlation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.641025641025642%\"\u003e\n \u003cp\u003e-0.728\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.035502958579883%\"\u003e\n \u003cp\u003e-0.767\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"24.65483234714004%\"\u003e\n \u003cp\u003e-0.698\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" width=\"23.29803328290469%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAt 4 mm below the CEJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.15431164901664%\"\u003e\n \u003cp\u003eGT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.667170953101362%\"\u003e\n \u003cp\u003e1.03\u0026plusmn;0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.969742813918305%\"\u003e\n \u003cp\u003e0.90\u0026plusmn;0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.910741301059%\"\u003e\n \u003cp\u003e0.92\u0026plusmn;0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.668639053254438%\"\u003e\n \u003cp\u003eBT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.641025641025642%\"\u003e\n \u003cp\u003e0.93\u0026plusmn;0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.035502958579883%\"\u003e\n \u003cp\u003e0.78\u0026plusmn;0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"24.65483234714004%\"\u003e\n \u003cp\u003e0.82\u0026plusmn;0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.668639053254438%\"\u003e\n \u003cp\u003ePearson correlation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.641025641025642%\"\u003e\n \u003cp\u003e-0.286\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.035502958579883%\"\u003e\n \u003cp\u003e-0.298\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"24.65483234714004%\"\u003e\n \u003cp\u003e-0.282\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" width=\"23.29803328290469%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAt 6 mm below the CEJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.15431164901664%\"\u003e\n \u003cp\u003eGT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.667170953101362%\"\u003e\n \u003cp\u003e1.15\u0026plusmn;0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.969742813918305%\"\u003e\n \u003cp\u003e1.10\u0026plusmn;0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.910741301059%\"\u003e\n \u003cp\u003e0.88\u0026plusmn;0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.668639053254438%\"\u003e\n \u003cp\u003eBT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.641025641025642%\"\u003e\n \u003cp\u003e0.77\u0026plusmn;0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.035502958579883%\"\u003e\n \u003cp\u003e0.41\u0026plusmn;0.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"24.65483234714004%\"\u003e\n \u003cp\u003e0.73\u0026plusmn;0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.668639053254438%\"\u003e\n \u003cp\u003ePearson correlation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.641025641025642%\"\u003e\n \u003cp\u003e0.036\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.035502958579883%\"\u003e\n \u003cp\u003e-0.079\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"24.65483234714004%\"\u003e\n \u003cp\u003e-0.066\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e**Confidence levels (bilateral) of \u0026lt; 0.01 indicate a significant correlation;\u003c/p\u003e\n\u003cp\u003e*Confidence levels (bilateral) \u0026lt;0.05 indicate a significant correlation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u0026nbsp;\u003c/strong\u003eGT and BT at 2, 4, and 6 mm apical to the CEJ measured by M2\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003eLevel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.057663125948405%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.271623672230653%\"\u003e\n \u003cp\u003eCentral incisors(CI)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.030349013657055%\"\u003e\n \u003cp\u003eLateral incisors(LI)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.66464339908953%\"\u003e\n \u003cp\u003eCanines(CA)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAt 2 mm below the CEJ\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.057663125948405%\"\u003e\n \u003cp\u003eGT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.271623672230653%\"\u003e\n \u003cp\u003e1.10\u0026plusmn;0.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.030349013657055%\"\u003e\n \u003cp\u003e0.92\u0026plusmn;0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.94\u0026plusmn;0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003eAt 2 mm below the CEJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.057663125948405%\"\u003e\n \u003cp\u003eBT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.271623672230653%\"\u003e\n \u003cp\u003e0.52\u0026plusmn;0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.030349013657055%\"\u003e\n \u003cp\u003e0.41\u0026plusmn;0.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.42\u0026plusmn;0.40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.057663125948405%\"\u003e\n \u003cp\u003ePearson correlation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.271623672230653%\"\u003e\n \u003cp\u003e-0.707\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.030349013657055%\"\u003e\n \u003cp\u003e-0.768\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.66464339908953%\"\u003e\n \u003cp\u003e-0.585\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.057663125948405%\"\u003e\n \u003cp\u003eGT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.271623672230653%\"\u003e\n \u003cp\u003e0.86\u0026plusmn;0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.030349013657055%\"\u003e\n \u003cp\u003e0.76\u0026plusmn;0.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.78\u0026plusmn;0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003eAt 4 mm below the CEJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.057663125948405%\"\u003e\n \u003cp\u003eBT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.271623672230653%\"\u003e\n \u003cp\u003e0.76\u0026plusmn;0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.030349013657055%\"\u003e\n \u003cp\u003e0.66\u0026plusmn;0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.73\u0026plusmn;0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.057663125948405%\"\u003e\n \u003cp\u003ePearson correlation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.271623672230653%\"\u003e\n \u003cp\u003e-0.319\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.030349013657055%\"\u003e\n \u003cp\u003e-0.292\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.66464339908953%\"\u003e\n \u003cp\u003e-0.197\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.057663125948405%\"\u003e\n \u003cp\u003eGT (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.271623672230653%\"\u003e\n \u003cp\u003e0.98\u0026plusmn;0.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.030349013657055%\"\u003e\n \u003cp\u003e0.97\u0026plusmn;0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.82\u0026plusmn;0.23\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003eAt 6 mm below the CEJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.66464339908953%\"\u003e\n \u003cp\u003eBT\u0026nbsp;(mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.66\u0026plusmn;0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.030349013657055%\"\u003e\n \u003cp\u003e0.37\u0026plusmn;0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.59\u0026plusmn;0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"23.975720789074355%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.66464339908953%\"\u003e\n \u003cp\u003ePearson correlation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.030349013657055%\"\u003e\n \u003cp\u003e0.163\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.66464339908953%\"\u003e\n \u003cp\u003e0.202\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e**Confidence levels (bilateral) of \u0026lt; 0.01 indicate a significant correlation; *Confidence levels (bilateral) \u0026lt;0.05 indicate a significant correlation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u0026nbsp;\u003c/strong\u003eThe mean\u0026plusmn;standard deviation of GT and BT (mm) in maxillary anterior teeth \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"18.996415770609318%\"\u003e\n \u003cp\u003eTooth types\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"42.29390681003584%\"\u003e\n \u003cp\u003eM1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" width=\"38.70967741935484%\"\u003e\n \u003cp\u003eM2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"18.996415770609318%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.939068100358423%\"\u003e\n \u003cp\u003eGT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003eBT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003eGT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003eBT\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"18.996415770609318%\"\u003e\n \u003cp\u003eCI\u0026nbsp;(mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.939068100358423%\"\u003e\n \u003cp\u003e1.14\u0026plusmn;0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.74\u0026plusmn;0.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.98\u0026plusmn;0.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.65\u0026plusmn;0.18\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"18.996415770609318%\"\u003e\n \u003cp\u003eLI\u0026nbsp;(mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.939068100358423%\"\u003e\n \u003cp\u003e1.00\u0026plusmn;0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.54\u0026plusmn;0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.88\u0026plusmn;0.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.50\u0026plusmn;0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"18.996415770609318%\"\u003e\n \u003cp\u003eCA\u0026nbsp;(mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.939068100358423%\"\u003e\n \u003cp\u003e0.94\u0026plusmn;0.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.70\u0026plusmn;0.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.83\u0026plusmn;0.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.60\u0026plusmn;0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"18.996415770609318%\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.939068100358423%\"\u003e\n \u003cp\u003e0.009\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.008\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.030\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"19.35483870967742%\"\u003e\n \u003cp\u003e0.016\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\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":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"gingival thickness (GT), bone thickness (BT), digital intraoral scanning, CBCT","lastPublishedDoi":"10.21203/rs.3.rs-729394/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-729394/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe aim of this study is to noninvasively assess the relationship between the labial gingival thickness (GT) and the underlying bone thickness (BT) of the maxillary anterior teeth by two digital techniques. GT and BT were measured at 2、4 and 6 mm apical to the cemento-enamel junction (CEJ) by two digital techniques: M1- cone-beam computed tomography (CBCT) and M2- digital intraoral scanning (DIS) combined with CBCT (30 healthy participants, 172 maxillary anterior teeth). Pearson's correlation coefficient was calculated to assess the correlation between GT and BT. A significant negative correlation was identified between GT and BT at 2、4 mm apical to the CEJ for central incisors (CI), lateral incisors (LI), and canines (CA) both by M1 and M2, but not at 4 mm apical to the CEJ for CA (M2) or at 6 mm apical to the CEJ for all (M1, M2). The labial BT was demonstrated\u0026thinsp;\u0026lt;\u0026thinsp;1 mm in most cases (85% of the CI; 97% of the LI; and 90% of the CA). Within the limitation of this study, it is concluded that the GT and BT seems to be negatively correlated in most cases, which should be cautious clinically.\u003c/p\u003e","manuscriptTitle":"Assessment of the Relationship Between Labial Gingival Thickness and Underlying Bone Thickness in Maxillary Anterior Teeth by Two Digital Techniques","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-07-23 22:25:35","doi":"10.21203/rs.3.rs-729394/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2021-10-15T16:17:14+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2021-10-01T06:42:09+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"49b64015-f57c-4d1a-acd6-f172158d8749","date":"2021-09-22T13:29:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2021-08-02T15:10:47+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2021-08-02T14:49:21+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2021-07-21T09:31:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2021-07-21T06:39:47+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2021-07-18T06:56:33+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"60754aa8-60bc-4344-9a1c-b10ff5e206f9","owner":[],"postedDate":"July 23rd, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":5935746,"name":"Dentistry"}],"tags":[],"updatedAt":"2022-01-13T12:24:26+00:00","versionOfRecord":{"articleIdentity":"rs-729394","link":"https://doi.org/10.1038/s41598-021-04721-7","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2022-01-13 12:24:26","publishedOnDateReadable":"January 13th, 2022"},"versionCreatedAt":"2021-07-23 22:25:35","video":"","vorDoi":"10.1038/s41598-021-04721-7","vorDoiUrl":"https://doi.org/10.1038/s41598-021-04721-7","workflowStages":[]},"version":"v1","identity":"rs-729394","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-729394","identity":"rs-729394","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}