Ventral transorbital apicoectomy of the maxillary second and third molar teeth in guinea pigs (Cavia porcellus): 26 cases

Ventral transorbital apicoectomy of the maxillary second and third molar teeth in guinea pigs (Cavia porcellus): 26 cases | 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 Ventral transorbital apicoectomy of the maxillary second and third molar teeth in guinea pigs (Cavia porcellus): 26 cases Justyna Ignaszak - Dziech, Vladimir Jekl, Tomasz Piasecki This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6108407/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract A common cause of teeth malocclusion and feeding disorders in guinea pigs is macrodontia and odontogenic abscesses. If the changes affect the maxillary second or third molar teethwhose apices are located at the base of the orbit, surgical access to them has so far been achieved through enucleation or orbital evisceration. The study aims to demonstrate a transorbital surgical approach to the apices of the maxillary molar teeth (M2 and M3) in guinea pigs, allowing preservation of the eye. Twenty six apicoectomies of maxillary M2 and M3 were performed. The skin was incised above the dorsal surface of the zygomatic arch below the lower eyelid at the level of the orbicularis oculi muscle. After dissection of the soft tissue, the orbital ligament was incised, and the eye bulbus was displaced dorsolaterally. The blunt dissection of the space between the salivary and zygomatic glands allowed direct access to the affected teeth apices. The apicoectomy was performed with a dental bur. After the procedure, the soft tissues and the eye were approximated back to their original position and the skin was sutured. Recovery was uneventful in all cases. The described method may be applied in cases where it is necessary to perform maxillary second and/or last molar tooth apicoectomy while avoiding damage to the eyeball. Care must be taken to protect the corneal surface of the affected eye. Transorbital maxilla apicoectomy macrodont abscess guinea pig dental disease malocclusion Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Apicoectomy is defined as the removal of the root tip/apex of a brachydont tooth and is used in small animal, canine and feline dentistry when conventional root canal treatment cannot completely cure a periapical infection. After creating an external access, the alveolar socket is cleaned and the root tip is removed with a dental drill, while the crown and the main part of the root remain in the socket (1, 2, 3). In rodents, such as the guinea pig (Cavia porcellus), it is not possible to speak of removal of the root tip. The dentition of guinea pigs is hypsodont and elodont, i.e. they have long crowns, grow continuously throughout their lives and are subject to constant wear of the occlusal surface (5, 6, 7, 8, 9). Furthermore, all teeth are aradicular and have an open apex containing germ cells and an anatomical crown comprising the reserve and clinical crowns. The pulp cavity, which is also filled with germinal tissue, extends from the apex towards the occlusal surface and into the crown. Each incisor of a guinea pig has a single pulp cavity, whereas each premolar and each molar have two pulp cavities (5). Therefore, in rodents, the apical part of the tooth crown is removed during apicoectomy. After the procedure is performed and the germinal cells are removed, the deposition of new tooth substance (tooth growth) ceases. However, the tooth crown continues to move towards the occlusal surface/gingivally due to the action of the periodontal ligaments, and the tooth is still subject to continuous wear of the occlusal surface (10). As the remainder of the tooth crown stays in the alveolar socket, healing processes take place so that the apical part of the socket is already filled with healing tissue when a small protruding crown fragment is extracted. Apicoectomy can be performed both in sterile conditions to halt further tooth growth, and also when tooth inflammation is suspected. In guinea pigs, apicoectomy is most often performed in cases of macrodontia or odontogenic abscesses formation. Macrodont teeth are, by definition, larger than normal teeth. Structural changes have been observed in the crown and apex of macrodont teeth in guinea pigs (5). These changes most commonly occur in the maxillary and mandibular second and third molars (5, 6, 7). The enlargement of the tooth circumference in guinea pigs leads to malocclusion and feeding difficulties, making them frequent dental patients. A similar situation occurs with periapical inflammation of these teeth, which causes significant pain at the base of the orbit and contributes to feeding difficulties and exophthalmos. A search of databases Medline, Web of Knowledge, and Scince Direct with the string “guinea pig” AND “apicoectomy” OR “apicectomy” OR “macrodontia” OR “abscess” on February 18, 2025, and review of 3 recent textbooks (citations) described the surgical access to the maxillary second and third molar teeth, which was associated with enucleation or evisceration. This study aims to demonstrate a novel surgical access to the maxillary second and third molar apices in guinea pigs via ventral transorbital approach, allowing apicoectomy without enucleation. Materials and Methods Case selection, inclusion criteria The prospective study includes only client-owned guinea pigs that underwent apicoectomy of the maxillary M2 or M3 without the need for enucleation or eviscerations, both during the procedure and in the recovery period. All procedures were performed for therapeutic purposes and involved animals belonging to private owners who consented to the procedures described in this paper and to the use of the results for publishing purposes. The procedures were performed at two institutions: by JID at the Centre for Diagnosis and Treatment of Exotic Animals, Zwierzyniec Veterinary Clinic, Wrocław, Poland, and by VJ at the Jekl & Hauptman Veterinary Clinic, Brno, Czech Republic. The study period ran from January 2023 to January 2024. Patients were presented with anorexia, weight loss, defecation disorders (soft faeces) or unilateral exophthalmos. All guinea pigs underwent a general physical examination, including oral cavity examination, urinalysis, plasma chemistry and haematology analyses, and computed tomography (CBCT, cone beam computed tomography) prior to the surgery. The detailed dental examination with a rigid endoscope, blood sampling, and the computed tomography of the head were performed under general anaesthesia (intramuscular premedication with 0.5 mg/kg midazolam, 0.3–0.5 mg/kg butorphanol and 1–3% isoflurane, or with alfaxalone 1 mg/kg and butorphanol 0.1 mg/kg and 1–3% isoflurane). Inflammation of the tooth crown or alveolar socket was suspected in cases where the CBCT examination showed the presence of hypodense areas of the crown (lysis), new bone formation, alveolar bone resorption and/or widening of the periodontal space. Both macrodont teeth and those without typical structural changes of macrodontia were assessed for these conditions. Patients with macrodont teeth without visible signs of inflammation were qualified for the procedure due to generalized malocclusion. In this situation the intervals between dental corrections were shorter than three weeks, there was no full improvement in appetite despite the dental trimming, and mucosal injury around the macrodont tooth persisted. Ocular disease The cornea and conjunctiva of all operated animals without odontogenic abscesses were healthy before surgery. All animals with odontogenic abscesses had mild to severe keratoconjunctivitis associated with exophthalmos and dry eye (Fig. 3 A, B). The data on age, sex, teeth operated on and indications for the individual procedures are summarised in Table 1 . Table 1 The table provides information on the age, gender of each patient, and the indications for performing apicoectomy on the listed teeth. F – female, M – male, Fc – spayed female, Mc – neutered male, L – left maxilla, R – right maxilla. Lp. Age at the time of surgery Sex Operated tooth Indications for the procedure 1. 2,5 M M3 L Macrodontia, suspected inflammation of the tooth/alveolus 2. 3,5 F M2 L Macrodontia 3. 2,5 M M2 R Macrodontia, suspected inflammation of the alveolus 4. 2,5 M M3 R Macrodontia, suspected inflammation of the alveolus 5. 5,5 M M2 L Macrodontia 6. 2,5 F M2 L Macrodontia, suspected inflammation of the tooth/alveolus 7. 2 M M2 L Macrodontia, suspected inflammation of the tooth/alveolus 8. 4 M M2 L Macrodontia 9. 2 M M2 R Macrodontia, suspected inflammation of the tooth/alveolus 10. 5,5 F M2 L Macrodontia 11. 2,5 M M2 L Macrodontia 12. M M3 L Macrodontia, suspected inflammation of the tooth and alveolus 13. 3,5 M M2 L Macrodontia, suspected inflammation of the tooth/alveolus 14. 5,5 M M2 L Suspected inflammation of the tooth/alveolus 15. 3,5 M c M2 R Suspected inflammation of the tooth/alveolus 16. 3 M c M2 R Suspected inflammation of the tooth/alveolus 17. 5,5 F c M3 L Suspected inflammation of the tooth/alveolus 18. 3,5 F c M2 L Suspected inflammation of the tooth/alveolus 19. 5 F M2 L Suspected inflammation of the tooth/alveolus 20. 2,5 M M2 L Macrodontia, suspected inflammation of the tooth/alveolus 21. 2 M c M2 R Suspected inflammation of the tooth/alveolus 22. 4,5 M M2, M3 R Suspected inflammation of the tooth/alveolus 23. 3,5 M M3 L Suspected inflammation of the tooth/alveolus 24. 6 F c M2 L Suspected inflammation of the tooth/alveolus 25. 5 F c M3 L Suspected inflammation of the tooth/alveolus 26. 1,5 M M3 L Suspected inflammation of the tooth/alveolus Surgical procedure The patient's state of health was stabilised before the planned operation. The surgical procedures were performed by 1 of the authors (JID or VJ), both of whom are experienced surgeons. General anaesthesia was induced with a combination of butorphanol (0.3–0.5 mg/kg), medetomidine (0.05–0.1 mg/kg) and ketamine (10–15 mg/kg) administered intramuscularly. As additional analgesia, meloxicam (0.5 mg/kg) was administered subcutaneously at least one hour before the procedure. Another anaesthesia protocol included a combination of metamizole (50 mg/kg), buprenorphine (0.03 mg/kg), midazolam (0.1–0.2 mg/kg), medetomidine (0.02–0.04 mg/kg) and ketamine (3–10 mg/kg) administered intramuscularly. Anaesthesia was maintained with isoflurane via a face/nasal mask with or without ketamine infusion at a continuous rate (0.3 mg/kg/h). Anaesthesia monitoring included respiratory rhythm and depth monitoring, thoracic auscultation, ECG and SpO 2 measurement. Isotonic fluid therapy (10 mL/kg) was administered perioperatively via continuous infusion. The patient was positioned laterally with the rostral part of the head supported and straps were used to stabilise the position to ensure that the eyeball was perpendicular to the surgical table. The surgical site was prepared as standard, and the eyes were protected with ophthalmic ointment or gel. The surgical field and procedure were described using terminology consistent with Nomina Anatomica Veterinaria (5). The operative field included the periocular area (Fig. 1 , Fig. 2 A). The skin incision was made just above the zygomatic arch, at the level of the orbicularis oculi muscle (Fig. 2 B). The orbicularis oculi muscle was sharply dissected from the zygomatic bone, towards the direction of the orbital ligament. The rostral fragment of the orbital ligament was sharply removed. A Lone-star retractor was then attached to the wound to allow better operative view. If the procedure was performed due to macrodontia of M2 or M3 without signs of inflammation, the eyeball was gently displaced from the orbit and the space between the lacrimal and zygomatic glands was bluntly dissected. Once the orbital floor was reached and the apex of the tooth was exposed, the periosteum was retracted from the alveolar bone using a periosteal elevator. A spatula was used to retract the lacrimal gland dorsally (Fig. 2 C). The osteotomy of the alveolar bone was performed with a round burr on a dental micromotor handpiece (30,000 rpm). After reaching the apex of the affected tooth, drilling was continued to complete the apicoectomy. After complete apicoectomy, the surgical field was debrided with cotton tips, sterile saline solution and surgical suction. The instruments were withdrawn, and the eyeball was returned to the orbit. The skin was sutured with a simple interrupted pattern using non-absorbable 4–5/0 suture material (name) (Fig. 2 D). In the case of odontogenic abscesses, the wound was debrided with a bone curette and cotton-tips (Fig. 3 C). The alveolar osteotomy was performed as described above. Samples were taken for bacteriological analysis and an antibiogram was performed. After thorough debridement, the wound was marsupialized. A perioperative CBCT examination was performed after the procedure. (Fig. 4 ). As successful apicoectomy was only observed in cases where the entire apical part of the tooth was removed. Postoperative care and follow-up data Postoperative care included supportive care, fluid therapy and, if necessary, syringe feeding. Analgesia included an opioid (tramadol 10 mg/kg orally q12h) and NSAIDs (meloxicam 1 mg/kg orally q12h or metamizole 50 mg/kg, orally q8 or 12h), with optional gabapentin (25 mg/kg orally q12h). Buprenorphine (0.03 mg/kg intramuscularly q8h) was only administered in a short postoperative phase while the animal was hospitalised. Analgesic drugs were administered for at least 10–14 days. To protect the eyes, ophthalmological preparations such as hyaluronic acid and ofloxacin (only for keratitis and conjunctivitis) were administered in the form of ointments and drops for 10–14 days as required. In addition, systemic antibiotic therapy was administered: long-acting oxytetracycline (25 mg/kg subcutaneously q72h) or sulfamethoxazole + trimethoprim (25 mg/kg orally q12h) for 14 days to limit bacterial inflammation of the alveolus, ocular tissue and orbit. For bacterial abscesses, doxycycline (5 mg/kg orally q12h) and metronidazole (25 mg/kg orally q12h) were the antibiotics of first choice, which were then adjusted according to the results of bacteriology and antimicrobial susceptibility testing. In the case of an apicoectomy on a macrodontic tooth without signs of inflammation, the sutures were removed 14 days after the procedure. If the procedure involved marsupialisation of an abscess, the wounds were checked on the 3rd, 7th and 14th day after the procedure. On day 14, the stitches were removed and the wound was healed by secondary intention. Radiological checks of the tooth after apicoectomy were performed under general anaesthesia 30, 60 and possibly 100 days after the procedure. Regular dental corrections were performed as required. Results In 2023–2024, the apicoectomy was performed via the ventral transorbital approach in 26 privately kept guinea pigs (8 females and 18 males) aged between 1.5 and 6 years (mean 3.5 years). A total of 27 maxillary molars underwent apicoectomy (19 M2 and 8 M3); in one case, both M2 and M3 were operated on in a single procedure. Fourteen of the 27 teeth were macrodont teeth, and in 9 of these 14 cases an inflammation of the crown or tooth socket was suspected. The remaining 13 teeth showed no signs of macrodontia and underwent apicoectomy due to inflammation of the crown or tooth socket. General anaesthesia was performed without complications and all animals made a full recovery. Apicoectomy was performed in all cases and the eyeball was preserved. All operated patients survived the postoperative recovery period until the removal of the crown after apicoectomy. The postoperative wound healed properly in all patients and the socket healed completely without complications. The operated tooth crown was extracted or felted out within 2 to 4 months. In patients diagnosed with macrodontia without signs of inflammation and without corneal damage prior to procedure, tarsorrhaphy was not performed immediately after procedure. No eye complications were observed in 8/14 patients (57%). Mild ocular complications, which included superficial corneal injury and mild conjunctival swelling, occurred in 3/14 (21%) patients but did not require a change in pharmacological treatment. In both the cases without complications and those with mild complications, the standard treatment regimen included 0.4% hyaluronic acid gel applied 4–5 times daily and ofloxacin ointment applied 3 times daily for 7–10 days. In severe complications (3/14 patients (21%)) such as extensive corneal injuries with stromal oedema and severe conjunctival swelling, a complete temporary tarsorrhaphy was also performed for 3–5 days. In this case, the continuation of local ophthalmological preparations was discontinued. The treatment lasted 10–14 days in these cases. In the patients with odontogenic abscesses, the conjunctiva and cornea healed within 5–21 days after the procedure. In 2 guinea pigs, wound healing was unsatisfactory due to the presence of inflamed bone sequences, and these patients had to undergo surgery on the 5th and 7th day. After the second procedure, the wound was completely healed within the next 7–14 days. Discussion Dental disease is a common reason why guinea pigs visit an exotic animal veterinarian in daily practise. In a study by Minarikova et al (2015), the incidence of dental disease was 36.3% (363 animals out of 1000 guinea pigs). Patients are usually presented with reduced appetite, production of small faecal pellets or weight loss (13, 14). A common cause of malocclusion in guinea pigs is periapical inflammation or macrodontia. These pathologies often affect the last two molars in both the upper and lower jaw (6, 7). The use of computed tomography in the diagnosis of dental diseases enables the detection of inflammatory and structural dental alterations at an early stage, allowing earlier surgical intervention (16, 17, 18). This is particularly true for pathological changes in the second and third maxillary molars of the guinea pig, whose apices are located in the ventral part of the orbit. Both inflammation with abscess formation and macrodontia in advanced stages lead to exophthalmos and secondary corneal damage, which is also associated with severe pain. If these changes are not diagnosed in time, enucleation may be necessary. In periapical abscesses, the only effective treatment is extraction of the inflamed tooth and debridement of the abscess capsule and alveolus (18). The affected tooth can be extracted or an apicoectomy can be performed (18). To date, apicoectomy has been sporadically mentioned for the treatment of dental disease in guinea pigs (18, 19, 20). Therefore, this is the first study to describe the use of apicoectomy for both periapical abscesses and malocclusion due to macrodontia. In addition, this study describes an osteotomic approach to the apices of the second and third upper molars, which allows the eyeball to be preserved. To correctly perform an apicoectomy on a hypsodont and elodont tooth, the entire apical part of the crown must be removed and the pulp cavity cleaned of germinal cells. It should be noted that each premolar and molar tooth of a guinea pig has two pulp cavities, and each of them must be thoroughly cleaned. Inflammation of the alveolar socket often result in resorption of the apical part of the crown and the alveolar bone. Therefore, there is no significant difficulty in effectively removing the growth zone of the tooth. Similarly, in macrodont teeth, the structural remodelling process begins at the apex of the tooth, with hard tissue filling the pulp cavities and significantly reducing the oulopal cavity (5). Thus, structural remodelling also facilitates proper apicoectomy, especially since both the crown and the apex of the tooth are enlarged and thus more surgically accessible. In the authors' experience, despite the interruption of tooth growth after apicoectomy, the crown moves towards the occlusion and continues to wear down, leaving a healed alveolar socket. This is possible due to the activity of the dentoalveolar ligaments, which constantly change their position and move the crown coronally/intraorally (12). Incorrectly performed apicoectomy, in which germinal cells remain in the apex or pulp cavity, can lead to partial regrowth of the crown, although complete regrowth of the crown is rare (19). Such situations are likely to lead to complications during alveolar healing. In odontogenic abscesses with pus fistulae into the orbital space, surgical access is easier in the authors' experience, as the pus pushes the ocular structures and the lacrimal glands away from each other, allowing the surgeon to reach the affected apex directly after careful wound debridement and pus removal. Corneal damage is one of the most common complications of craniofacial surgery. In humans undergoing general anaesthesia for non–ocular surgery, the incidence of corneal damage can be as high as 44% (21), while in dogs it ranges from 1.9% (22) to 19.1% (23). Although the procedure described in our study does not directly affect the eyeball, the risk of ocular complications is high due to the manipulation of the orbit. The incidence of corneal abrasions as a result of the procedure was 23%. Most complications are due to lagophthalmos during anaesthesia (24, 25). To protect the eyeball, an intraoperative tarsorrhaphy could be performed (25). However, as the eyeball has to be lifted and moved out of the orbit during the described procedure, this is not recommended. Tear production decreases during anaesthesia, which contributes to drying of the corneal surface (24, 25, 26). To avoid such complications, eye ointments should be applied to the surface of the eyeball during the procedure. Ointments remain on the corneal surface longer than drops and offer better protection (25, 27, 28). Due to direct contact with the lacrimal gland and zygomatic gland during the procedure, there is a risk of postoperative swelling of these structures, which may lead to exophthalmos after the procedure and further expose the cornea to desiccation. Both the anaesthetics used during anaesthesia (25) and the pressure from gland swelling disrupt the blood flow in the orbit, which can lead to corneal oedema. To mitigate such complications, non-steroidal (e.g. meloxicam) or steroidal (e.g. dexamethasone) anti-inflammatory drugs should be used during the recovery period (27, 28). In odontogenic abscesses, the exophthalmic eye usually already shows corneal damage and keratitis due to the dry eye, so that the healing of the cornea is accelerated as soon as the eye is brought back into the correct position. Another risk factor is manipulation with instruments in close proximity to the eyeball (24, 25). In the surgical field, instruments should be used with extreme caution and both the surgical drape and the retractor should not touch the eyeball. Root apex resection plays an important role in the treatment of dental disease in guinea pigs due to periapical infection and macrodontia. It allows removal of the affected tooth in a much less traumatic way than conventional intraoral extraction and ensures better healing of the alveolus. The described approach also enables the preservation of the socket, which is crucial if it has not been damaged by changes to the tooth tips. This procedure is applicable to both periapical abscesses and non-inflammatory changes (i.e. macrodontia). Due to the high exposure of the eyeball during the procedure and the manipulations within the orbit, adequate protection of the eyeball is required during the procedure and in the postoperative period. In the authors' experience, the opposing mandibular molars must be monitored for clinical crown lengthening, especially in cases where two maxillary molars have been operated on. If this is the case, an apicoectomy of the mandibular second and third molars should also be performed. Declarations Ethical approval and relevant guidelines: The animals belonged to private owners, and all procedures were carried out for therapeutic purposes, so the work concerns clinical cases and approval from the Institutional Animal Care and Use Committee was not required (Ethical Statement of Wroclaw University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Animal Welfare Advisory Team, 1/2025). All owners provided informed consent for the described procedures and the use of data for publication purposes. Consent for publication: not applicable Data availability statement: More detailed data on patients and diagnostic procedures are available upon contact with the corresponding author: Justyna Ignaszak–Dziech, [email protected] Conflict of interest: I declare that the authors have no competing interests as defined by BMC or other interests that might be perceived to influence the results and/or discussion reported in this paper. Funding: The APC/BPC is financed by Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland Author contribution: JID conceived and the study design, performed diagnostics and surgical procedures and drafted the manuscript. VJ performed diagnostics and surgical procedures, revised the manuscript. TP participated in coordination of the study and revised the manuscript. All authors read and approved the final manuscript. Acknowledgement: The research was partly financed by a grant VETUNI Brno 2021ITA15 Author information (optional): not applicable References Maher WP, Johnson RL, Hess J, Steiman HR. Biocompatibility of retrograde filling materials in the ferret canine. Amalgam and IRM. Oral Surg Oral Med Oral Pathol. 1992; doi: 10.1016/0030-4220(92)90021-h. Hennet P, Girard N. Surgical Endodontics in Dogs: A Review. J Vet Dent 2005; doi: 10.1177/089875640502200301 Böhmer E. Dentistry in Rabbits and Rodents. USA: John Wiley and Sons; 2015. Dziech J, Piasecki T. Anatomical and histological structure of the cavy’s teeth as a basis for diagnosis of dental diseases. Med Wet. 2021; doi: 10.21521/mw.6500 Ignaszak-Dziech J, Kuropka P, Piasecki T. Histological characteristics of macrodontic cheek teeth of guinea pigs. BMC Vet Res 2023; https://doi.org/10.1186/s12917-023-03567-7 Köstlinger S, Witt S, Fehr M. Macrodontia in Guinea Pigs (Cavia porcellus) Radiological findings and localisation in 131 patients. J Exot Pet Med 2021; doi: 10.1053/j.jepm.2021.08.002 Köstlinger S, Witt S, Fehr M. Radiological Appearance and Localization of Macrodontia in Guinea Pigs. In: Proceedings of the 3rd International Conference on Avian, Herpetological and Exotic Mammal Medicine, Venice, March 27 to 29 2017. Venice; 2017. S. 614-5 Gosse H.: Nomina anatomiaca veterinaria. World Association of Veterinary Anatomists 2017. Gale Cooper MD, Alan L, Schiller MD. Anatomy of the Guinea Pig. Harvard University Press, 1975 Johansen JR. Response of the intermediate plexus of the guinea pig molar to experimental trauma. Acta Odontol Scand. 1970; doi: 10.3109/00016357009028239 . Popesko P, Rajtova V, Horak J. Colour Atlas Of Anatomy Of Small Laboratory Animals. St. Louis, MO, Saunders, 2002 Minarikova A, Hauptman K, Jeklova E, Knotek Z, Jekl V. Diseases in pet guinea pigs: a retrospective study in 1000 animals. Vet Rec. 2015 doi: 10.1136/vr.103053 . O’Rouke DP: Disease problems of guinea pigs, in Quesenberry KE, Carpenter JW. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery, St. Louis, MO, Saunders, 2004 Schweda MC, Hassan J, Böhler A, Tichy A, Reiter AM, Künzel F. The role of computed tomography in the assessment of dental disease in 66 guinea pigs. Vet Rec. 2014; doi: 10.1136/vr.101469 . Marcy J. Souza, Cheryl B. Greenacre, James S. Avenell, Jonathan S. Wall, Gregory B. Daniel. Diagnosing a Tooth Root Abscess in a Guinea Pig (Cavia porcellus) Using Micro Computed Tomography Imaging. J Exot Pet Med, 2006; Vol 15, Issue 4. Capello V, Cauduro A. Clinical Technique: Application of Computed Tomography for Diagnosis of Dental Disease in the Rabbit, Guinea Pig, and Chinchilla. J Exot Pet Med. 2008; Vol 17, Issue 2. Johansen JR. Response of the intermediate plexus of the guinea pig molar to experimental trauma. Acta Odontol Scand. 1970; doi: 10.3109/00016357009028239 . White E, Crosse MM. The aetiology and prevention of peri-operative corneal abrasions. Anaesthesia. 1998; doi: 10.1046/j.1365-2044.1998.00269.x . Jekl V. Macrodont teeth in guinea pigs. In: Proceedings of the 4th International Conference on Avian, Herpetological and Exotic Mammal Medicine, London, 28th April to 2nd May 2019. London; 2019 Kliszcz. J 2019 Apicoectomy as an alternative for tooth extraction in guinea pigs. In: Proceedings of the 4th International Conference on Avian, Herpetological and Exotic Mammal Medicine, London, 28th April to 2nd May 2019. London; 2019. Legendre L. Anatomy and Disorders of the Oral Cavity of Guinea Pigs. Vet Clin North Am Exot Anim Pract. 2016; doi: 10.1016/j.cvex.2016.04.006 . Dawson C, Sanchez RF. A prospective study of the prevalence of corneal surface disease in dogs receiving prophylactic topical lubrication under general anesthesia. Vet Ophthalmol. 2016; doi: 10.1111/vop.12272 . Batra YK, Bali IM. Corneal abrasions during general anesthesia. Anesth Analg., 1977; doi: 10.1213/00000539-197705000-00010 . Grixti A, Sadri M, Watts MT. Corneal protection during general anesthesia for nonocular surgery. Ocul Surf. 2013; doi: 10.1016/j.jtos.2012.10.003 . Andrew SE. Corneal diseases of rabbits. Vet Clin North Am Exot Anim Pract. 2002; doi: 10.1016/s1094-9194(01)00003-2 . Park YW, Son WG, Jeong MB, Seo K, Lee LY, Lee I. Evaluation of risk factors for development of corneal ulcer after nonocular surgery in dogs: 14 cases (2009–2011). J Am Vet Med Assoc. 2013; doi: 10.2460/javma.242.11.1544 . Baum J. Treatment of bacterial ulcers of the cornea in the rabbit: a comparison of administration by eye drops and subconjunctival injections. Trans Am Ophthalmol Soc. 1982. PMID: 6763800. Kanda T, Mizoguchi Y, Furumoto K, Shimizu Y, Maeta N, Furukawa T. Effect of Intramuscular Medetomidine Administration on Tear Flow in Rats. Vet Sci. 2020; doi: 10.3390/vetsci7020042 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6108407","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":435950268,"identity":"31fae47a-eae7-4e7d-b517-2de85a4eb8d3","order_by":0,"name":"Justyna Ignaszak - Dziech","email":"","orcid":"","institution":"University of Environmental and Life Sciences","correspondingAuthor":false,"prefix":"","firstName":"Justyna","middleName":"Ignaszak -","lastName":"Dziech","suffix":""},{"id":435950269,"identity":"9491a195-a479-4fd7-bf9d-e3eab8c144d2","order_by":1,"name":"Vladimir Jekl","email":"","orcid":"","institution":"VETUNI Brno","correspondingAuthor":false,"prefix":"","firstName":"Vladimir","middleName":"","lastName":"Jekl","suffix":""},{"id":435950270,"identity":"9c0bb46e-5cbc-4478-800c-edeba4ef1979","order_by":2,"name":"Tomasz Piasecki","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABEklEQVRIiWNgGAWjYDADNjB5QEIOymcG4QZsKnnQtRgjaWHErwUCDjAkNhDSYs/enfjxxx+GPD724w8f/Dhjkb7hdo/ZB4YK68QG6UbstvCc3SzNw8NQzMaTY2zYc0Mid8OdM8YzGM6kJzbIHMSuBahGmkGCIbGNIYdNmuEDkHsjdzMDY9vhxAaJRFxaNv/8YQDUwv/8+W+glnQDsJZ/eLVsk+BJAGqRSDBjZrghkQDR0oBHy5mz26x5DkgUs0m8MZbsOSNhOPPO+c8MCcfSjdtw+IW9vXfzzR9/bPLk+9MffvhxrE6e73ZbMsOHGmvZfunmA9i0QIFEAhIbiEFcNgk8GqBqkLSgMkbBKBgFo2CEAwC+2GJC4DJaQAAAAABJRU5ErkJggg==","orcid":"","institution":"University of Environmental and Life Sciences","correspondingAuthor":true,"prefix":"","firstName":"Tomasz","middleName":"","lastName":"Piasecki","suffix":""}],"badges":[],"createdAt":"2025-02-25 22:38:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6108407/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6108407/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":79648710,"identity":"571890f4-4f92-47d0-a9f4-f1807de9c75f","added_by":"auto","created_at":"2025-04-01 07:29:37","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":496892,"visible":true,"origin":"","legend":"\u003cp\u003eOrbital region on an anatomical specimen. 1 – eyeball, 2 – orbital ligament, 3 – lacrimal gland, 4 – zygomatic gland, 5 – fascia, 6 – masseter muscle, 7 – zygomatic arch, 8 – maxillary nerve, 9 – M2 maxillary tooth socket. (Courtesy of dr. Justyna Ignaszak – Dziech and Dr Tomasz Piasecki)\u003c/p\u003e","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6108407/v1/a90a1c895d73df89716d1f5d.jpg"},{"id":79647441,"identity":"9dcad7fe-d560-4b60-9aed-d57c1881ec5f","added_by":"auto","created_at":"2025-04-01 07:21:37","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2369873,"visible":true,"origin":"","legend":"\u003cp\u003eStages of an apicoectomy procedure via an orbital approach. A – preparation of the surgical field in the orbital region. B – eyeball protected with ophthalmic ointment. Skin incision made above the zygomatic arch. C – eyeball displaced from the orbit, exposing the apex of the M2 maxillary tooth after retracting the lacrimal and zygomatic glands with instruments. D – postoperative wound sutured with a single stitch, and the eyeball returned to the orbit. (Courtesy of dr. Justyna Ignaszak – Dziech and dr Tomasz Piasecki)\u003c/p\u003e","description":"","filename":"Fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6108407/v1/1b1a4ee33c40e755ac63d7d8.jpg"},{"id":79647447,"identity":"921c932e-360b-4a1b-a7b9-5ac3b792e568","added_by":"auto","created_at":"2025-04-01 07:21:38","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":3997107,"visible":true,"origin":"","legend":"\u003cp\u003eRight eye exophthalmos in a guinea pig associated with apical maxillary molar infection in a guinea pig (A-C). A – obvious left-sided exophthalmos, B – detailed view of the affected eye with keratoconjuncivitis and dry corneal surface, C – perioperative view of the incision and presence of pus. (Courtesy of dr. Vladimir Jekl)\u003c/p\u003e","description":"","filename":"Fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6108407/v1/c5b9c8cf33468030fc2f6c21.jpg"},{"id":79647442,"identity":"56558d75-e561-46d4-8ce2-015c4e92fbda","added_by":"auto","created_at":"2025-04-01 07:21:37","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":147659,"visible":true,"origin":"","legend":"\u003cp\u003eTomograms of a guinea pig's skull in the sagittal planes, showing the left maxillary cheek teeth. A – structural change typical of macrodontia visible in the mesial part of the M2 left maxillary tooth. Narrowed mesial pulp chamber, with the apex and distal pulp chamber normal. B – hypodense area at the apex of the M2 left maxillary tooth indicates a properly performed apicoectomy. (Courtesy of dr. Justyna Ignaszak – Dziech and dr Tomasz Piasecki)\u003c/p\u003e","description":"","filename":"fig4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6108407/v1/077349bbe2339ec50a12bdf7.jpg"},{"id":96801559,"identity":"6c277666-13a5-42cb-b5fd-eee7ad7c4098","added_by":"auto","created_at":"2025-11-26 08:39:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7485883,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6108407/v1/41c09338-1ddf-46b5-b3fe-e2ad5ea60108.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Ventral transorbital apicoectomy of the maxillary second and third molar teeth in guinea pigs (Cavia porcellus): 26 cases","fulltext":[{"header":"Introduction","content":"\u003cp\u003eApicoectomy is defined as the removal of the root tip/apex of a brachydont tooth and is used in small animal, canine and feline dentistry when conventional root canal treatment cannot completely cure a periapical infection. After creating an external access, the alveolar socket is cleaned and the root tip is removed with a dental drill, while the crown and the main part of the root remain in the socket (1, 2, 3).\u003c/p\u003e \u003cp\u003eIn rodents, such as the guinea pig (Cavia porcellus), it is not possible to speak of removal of the root tip. The dentition of guinea pigs is hypsodont and elodont, i.e. they have long crowns, grow continuously throughout their lives and are subject to constant wear of the occlusal surface (5, 6, 7, 8, 9). Furthermore, all teeth are aradicular and have an open apex containing germ cells and an anatomical crown comprising the reserve and clinical crowns. The pulp cavity, which is also filled with germinal tissue, extends from the apex towards the occlusal surface and into the crown. Each incisor of a guinea pig has a single pulp cavity, whereas each premolar and each molar have two pulp cavities (5). Therefore, in rodents, the apical part of the tooth crown is removed during apicoectomy. After the procedure is performed and the germinal cells are removed, the deposition of new tooth substance (tooth growth) ceases. However, the tooth crown continues to move towards the occlusal surface/gingivally due to the action of the periodontal ligaments, and the tooth is still subject to continuous wear of the occlusal surface (10). As the remainder of the tooth crown stays in the alveolar socket, healing processes take place so that the apical part of the socket is already filled with healing tissue when a small protruding crown fragment is extracted.\u003c/p\u003e \u003cp\u003eApicoectomy can be performed both in sterile conditions to halt further tooth growth, and also when tooth inflammation is suspected. In guinea pigs, apicoectomy is most often performed in cases of macrodontia or odontogenic abscesses formation. Macrodont teeth are, by definition, larger than normal teeth. Structural changes have been observed in the crown and apex of macrodont teeth in guinea pigs (5). These changes most commonly occur in the maxillary and mandibular second and third molars (5, 6, 7). The enlargement of the tooth circumference in guinea pigs leads to malocclusion and feeding difficulties, making them frequent dental patients. A similar situation occurs with periapical inflammation of these teeth, which causes significant pain at the base of the orbit and contributes to feeding difficulties and exophthalmos.\u003c/p\u003e \u003cp\u003eA search of databases Medline, Web of Knowledge, and Scince Direct with the string \u0026ldquo;guinea pig\u0026rdquo; AND \u0026ldquo;apicoectomy\u0026rdquo; OR \u0026ldquo;apicectomy\u0026rdquo; OR \u0026ldquo;macrodontia\u0026rdquo; OR \u0026ldquo;abscess\u0026rdquo; on February 18, 2025, and review of 3 recent textbooks (citations) described the surgical access to the maxillary second and third molar teeth, which was associated with enucleation or evisceration. This study aims to demonstrate a novel surgical access to the maxillary second and third molar apices in guinea pigs via ventral transorbital approach, allowing apicoectomy without enucleation.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eCase selection, inclusion criteria\u003c/p\u003e \u003cp\u003eThe prospective study includes only client-owned guinea pigs that underwent apicoectomy of the maxillary M2 or M3 without the need for enucleation or eviscerations, both during the procedure and in the recovery period. All procedures were performed for therapeutic purposes and involved animals belonging to private owners who consented to the procedures described in this paper and to the use of the results for publishing purposes. The procedures were performed at two institutions: by JID at the Centre for Diagnosis and Treatment of Exotic Animals, Zwierzyniec Veterinary Clinic, Wrocław, Poland, and by VJ at the Jekl \u0026amp; Hauptman Veterinary Clinic, Brno, Czech Republic. The study period ran from January 2023 to January 2024.\u003c/p\u003e \u003cp\u003ePatients were presented with anorexia, weight loss, defecation disorders (soft faeces) or unilateral exophthalmos. All guinea pigs underwent a general physical examination, including oral cavity examination, urinalysis, plasma chemistry and haematology analyses, and computed tomography (CBCT, cone beam computed tomography) prior to the surgery. The detailed dental examination with a rigid endoscope, blood sampling, and the computed tomography of the head were performed under general anaesthesia (intramuscular premedication with 0.5 mg/kg midazolam, 0.3\u0026ndash;0.5 mg/kg butorphanol and 1\u0026ndash;3% isoflurane, or with alfaxalone 1 mg/kg and butorphanol 0.1 mg/kg and 1\u0026ndash;3% isoflurane).\u003c/p\u003e \u003cp\u003eInflammation of the tooth crown or alveolar socket was suspected in cases where the CBCT examination showed the presence of hypodense areas of the crown (lysis), new bone formation, alveolar bone resorption and/or widening of the periodontal space. Both macrodont teeth and those without typical structural changes of macrodontia were assessed for these conditions. Patients with macrodont teeth without visible signs of inflammation were qualified for the procedure due to generalized malocclusion. In this situation the intervals between dental corrections were shorter than three weeks, there was no full improvement in appetite despite the dental trimming, and mucosal injury around the macrodont tooth persisted.\u003c/p\u003e \u003cp\u003eOcular disease\u003c/p\u003e \u003cp\u003eThe cornea and conjunctiva of all operated animals without odontogenic abscesses were healthy before surgery. All animals with odontogenic abscesses had mild to severe keratoconjunctivitis associated with exophthalmos and dry eye (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e3\u003c/span\u003eA, B). The data on age, sex, teeth operated on and indications for the individual procedures are summarised in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\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\u003eThe table provides information on the age, gender of each patient, and the indications for performing apicoectomy on the listed teeth. F \u0026ndash; female, M \u0026ndash; male, Fc \u0026ndash; spayed female, Mc \u0026ndash; neutered male, L \u0026ndash; left maxilla, R \u0026ndash; right maxilla.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" 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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLp.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAge at the time of surgery\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOperated tooth\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIndications for the procedure\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM3 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 R\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM3 R\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 R\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM3 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the tooth and alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 R\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 R\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM3 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e19.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMacrodontia, suspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e21.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 R\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e22.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2, M3 R\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e23.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM3 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM2 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM3 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e26.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eM3 L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSuspected inflammation of the tooth/alveolus\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\u003eSurgical procedure\u003c/p\u003e \u003cp\u003eThe patient's state of health was stabilised before the planned operation. The surgical procedures were performed by 1 of the authors (JID or VJ), both of whom are experienced surgeons. General anaesthesia was induced with a combination of butorphanol (0.3\u0026ndash;0.5 mg/kg), medetomidine (0.05\u0026ndash;0.1 mg/kg) and ketamine (10\u0026ndash;15 mg/kg) administered intramuscularly. As additional analgesia, meloxicam (0.5 mg/kg) was administered subcutaneously at least one hour before the procedure. Another anaesthesia protocol included a combination of metamizole (50 mg/kg), buprenorphine (0.03 mg/kg), midazolam (0.1\u0026ndash;0.2 mg/kg), medetomidine (0.02\u0026ndash;0.04 mg/kg) and ketamine (3\u0026ndash;10 mg/kg) administered intramuscularly. Anaesthesia was maintained with isoflurane via a face/nasal mask with or without ketamine infusion at a continuous rate (0.3 mg/kg/h). Anaesthesia monitoring included respiratory rhythm and depth monitoring, thoracic auscultation, ECG and SpO\u003csub\u003e2\u003c/sub\u003e measurement. Isotonic fluid therapy (10 mL/kg) was administered perioperatively via continuous infusion.\u003c/p\u003e \u003cp\u003eThe patient was positioned laterally with the rostral part of the head supported and straps were used to stabilise the position to ensure that the eyeball was perpendicular to the surgical table. The surgical site was prepared as standard, and the eyes were protected with ophthalmic ointment or gel.\u003c/p\u003e \u003cp\u003eThe surgical field and procedure were described using terminology consistent with \u003cem\u003eNomina Anatomica Veterinaria\u003c/em\u003e (5). The operative field included the periocular area (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003eA). The skin incision was made just above the zygomatic arch, at the level of the orbicularis oculi muscle (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003eB). The orbicularis oculi muscle was sharply dissected from the zygomatic bone, towards the direction of the orbital ligament. The rostral fragment of the orbital ligament was sharply removed. A Lone-star retractor was then attached to the wound to allow better operative view.\u003c/p\u003e \u003cp\u003eIf the procedure was performed due to macrodontia of M2 or M3 without signs of inflammation, the eyeball was gently displaced from the orbit and the space between the lacrimal and zygomatic glands was bluntly dissected. Once the orbital floor was reached and the apex of the tooth was exposed, the periosteum was retracted from the alveolar bone using a periosteal elevator. A spatula was used to retract the lacrimal gland dorsally (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003eC). The osteotomy of the alveolar bone was performed with a round burr on a dental micromotor handpiece (30,000 rpm). After reaching the apex of the affected tooth, drilling was continued to complete the apicoectomy. After complete apicoectomy, the surgical field was debrided with cotton tips, sterile saline solution and surgical suction. The instruments were withdrawn, and the eyeball was returned to the orbit. The skin was sutured with a simple interrupted pattern using non-absorbable 4\u0026ndash;5/0 suture material (name) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e2\u003c/span\u003eD). In the case of odontogenic abscesses, the wound was debrided with a bone curette and cotton-tips (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e3\u003c/span\u003eC). The alveolar osteotomy was performed as described above. Samples were taken for bacteriological analysis and an antibiogram was performed. After thorough debridement, the wound was marsupialized.\u003c/p\u003e \u003cp\u003eA perioperative CBCT examination was performed after the procedure. (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). As successful apicoectomy was only observed in cases where the entire apical part of the tooth was removed.\u003c/p\u003e \u003cp\u003ePostoperative care and follow-up data\u003c/p\u003e \u003cp\u003ePostoperative care included supportive care, fluid therapy and, if necessary, syringe feeding. Analgesia included an opioid (tramadol 10 mg/kg orally q12h) and NSAIDs (meloxicam 1 mg/kg orally q12h or metamizole 50 mg/kg, orally q8 or 12h), with optional gabapentin (25 mg/kg orally q12h). Buprenorphine (0.03 mg/kg intramuscularly q8h) was only administered in a short postoperative phase while the animal was hospitalised. Analgesic drugs were administered for at least 10\u0026ndash;14 days. To protect the eyes, ophthalmological preparations such as hyaluronic acid and ofloxacin (only for keratitis and conjunctivitis) were administered in the form of ointments and drops for 10\u0026ndash;14 days as required. In addition, systemic antibiotic therapy was administered: long-acting oxytetracycline (25 mg/kg subcutaneously q72h) or sulfamethoxazole\u0026thinsp;+\u0026thinsp;trimethoprim (25 mg/kg orally q12h) for 14 days to limit bacterial inflammation of the alveolus, ocular tissue and orbit. For bacterial abscesses, doxycycline (5 mg/kg orally q12h) and metronidazole (25 mg/kg orally q12h) were the antibiotics of first choice, which were then adjusted according to the results of bacteriology and antimicrobial susceptibility testing.\u003c/p\u003e \u003cp\u003eIn the case of an apicoectomy on a macrodontic tooth without signs of inflammation, the sutures were removed 14 days after the procedure. If the procedure involved marsupialisation of an abscess, the wounds were checked on the 3rd, 7th and 14th day after the procedure. On day 14, the stitches were removed and the wound was healed by secondary intention. Radiological checks of the tooth after apicoectomy were performed under general anaesthesia 30, 60 and possibly 100 days after the procedure. Regular dental corrections were performed as required.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eIn 2023\u0026ndash;2024, the apicoectomy was performed via the ventral transorbital approach in 26 privately kept guinea pigs (8 females and 18 males) aged between 1.5 and 6 years (mean 3.5 years). A total of 27 maxillary molars underwent apicoectomy (19 M2 and 8 M3); in one case, both M2 and M3 were operated on in a single procedure. Fourteen of the 27 teeth were macrodont teeth, and in 9 of these 14 cases an inflammation of the crown or tooth socket was suspected. The remaining 13 teeth showed no signs of macrodontia and underwent apicoectomy due to inflammation of the crown or tooth socket.\u003c/p\u003e \u003cp\u003eGeneral anaesthesia was performed without complications and all animals made a full recovery. Apicoectomy was performed in all cases and the eyeball was preserved. All operated patients survived the postoperative recovery period until the removal of the crown after apicoectomy. The postoperative wound healed properly in all patients and the socket healed completely without complications. The operated tooth crown was extracted or felted out within 2 to 4 months.\u003c/p\u003e \u003cp\u003eIn patients diagnosed with macrodontia without signs of inflammation and without corneal damage prior to procedure, tarsorrhaphy was not performed immediately after procedure. No eye complications were observed in 8/14 patients (57%). Mild ocular complications, which included superficial corneal injury and mild conjunctival swelling, occurred in 3/14 (21%) patients but did not require a change in pharmacological treatment. In both the cases without complications and those with mild complications, the standard treatment regimen included 0.4% hyaluronic acid gel applied 4\u0026ndash;5 times daily and ofloxacin ointment applied 3 times daily for 7\u0026ndash;10 days. In severe complications (3/14 patients (21%)) such as extensive corneal injuries with stromal oedema and severe conjunctival swelling, a complete temporary tarsorrhaphy was also performed for 3\u0026ndash;5 days. In this case, the continuation of local ophthalmological preparations was discontinued. The treatment lasted 10\u0026ndash;14 days in these cases.\u003c/p\u003e \u003cp\u003eIn the patients with odontogenic abscesses, the conjunctiva and cornea healed within 5\u0026ndash;21 days after the procedure. In 2 guinea pigs, wound healing was unsatisfactory due to the presence of inflamed bone sequences, and these patients had to undergo surgery on the 5th and 7th day. After the second procedure, the wound was completely healed within the next 7\u0026ndash;14 days.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eDental disease is a common reason why guinea pigs visit an exotic animal veterinarian in daily practise. In a study by Minarikova et al (2015), the incidence of dental disease was 36.3% (363 animals out of 1000 guinea pigs). Patients are usually presented with reduced appetite, production of small faecal pellets or weight loss (13, 14). A common cause of malocclusion in guinea pigs is periapical inflammation or macrodontia. These pathologies often affect the last two molars in both the upper and lower jaw (6, 7). The use of computed tomography in the diagnosis of dental diseases enables the detection of inflammatory and structural dental alterations at an early stage, allowing earlier surgical intervention (16, 17, 18). This is particularly true for pathological changes in the second and third maxillary molars of the guinea pig, whose apices are located in the ventral part of the orbit. Both inflammation with abscess formation and macrodontia in advanced stages lead to exophthalmos and secondary corneal damage, which is also associated with severe pain. If these changes are not diagnosed in time, enucleation may be necessary. In periapical abscesses, the only effective treatment is extraction of the inflamed tooth and debridement of the abscess capsule and alveolus (18). The affected tooth can be extracted or an apicoectomy can be performed (18). To date, apicoectomy has been sporadically mentioned for the treatment of dental disease in guinea pigs (18, 19, 20). Therefore, this is the first study to describe the use of apicoectomy for both periapical abscesses and malocclusion due to macrodontia. In addition, this study describes an osteotomic approach to the apices of the second and third upper molars, which allows the eyeball to be preserved.\u003c/p\u003e \u003cp\u003eTo correctly perform an apicoectomy on a hypsodont and elodont tooth, the entire apical part of the crown must be removed and the pulp cavity cleaned of germinal cells. It should be noted that each premolar and molar tooth of a guinea pig has two pulp cavities, and each of them must be thoroughly cleaned. Inflammation of the alveolar socket often result in resorption of the apical part of the crown and the alveolar bone. Therefore, there is no significant difficulty in effectively removing the growth zone of the tooth. Similarly, in macrodont teeth, the structural remodelling process begins at the apex of the tooth, with hard tissue filling the pulp cavities and significantly reducing the oulopal cavity (5). Thus, structural remodelling also facilitates proper apicoectomy, especially since both the crown and the apex of the tooth are enlarged and thus more surgically accessible. In the authors' experience, despite the interruption of tooth growth after apicoectomy, the crown moves towards the occlusion and continues to wear down, leaving a healed alveolar socket. This is possible due to the activity of the dentoalveolar ligaments, which constantly change their position and move the crown coronally/intraorally (12). Incorrectly performed apicoectomy, in which germinal cells remain in the apex or pulp cavity, can lead to partial regrowth of the crown, although complete regrowth of the crown is rare (19). Such situations are likely to lead to complications during alveolar healing. In odontogenic abscesses with pus fistulae into the orbital space, surgical access is easier in the authors' experience, as the pus pushes the ocular structures and the lacrimal glands away from each other, allowing the surgeon to reach the affected apex directly after careful wound debridement and pus removal.\u003c/p\u003e \u003cp\u003eCorneal damage is one of the most common complications of craniofacial surgery. In humans undergoing general anaesthesia for non\u0026ndash;ocular surgery, the incidence of corneal damage can be as high as 44% (21), while in dogs it ranges from 1.9% (22) to 19.1% (23). Although the procedure described in our study does not directly affect the eyeball, the risk of ocular complications is high due to the manipulation of the orbit. The incidence of corneal abrasions as a result of the procedure was 23%. Most complications are due to lagophthalmos during anaesthesia (24, 25). To protect the eyeball, an intraoperative tarsorrhaphy could be performed (25). However, as the eyeball has to be lifted and moved out of the orbit during the described procedure, this is not recommended. Tear production decreases during anaesthesia, which contributes to drying of the corneal surface (24, 25, 26). To avoid such complications, eye ointments should be applied to the surface of the eyeball during the procedure. Ointments remain on the corneal surface longer than drops and offer better protection (25, 27, 28). Due to direct contact with the lacrimal gland and zygomatic gland during the procedure, there is a risk of postoperative swelling of these structures, which may lead to exophthalmos after the procedure and further expose the cornea to desiccation. Both the anaesthetics used during anaesthesia (25) and the pressure from gland swelling disrupt the blood flow in the orbit, which can lead to corneal oedema. To mitigate such complications, non-steroidal (e.g. meloxicam) or steroidal (e.g. dexamethasone) anti-inflammatory drugs should be used during the recovery period (27, 28). In odontogenic abscesses, the exophthalmic eye usually already shows corneal damage and keratitis due to the dry eye, so that the healing of the cornea is accelerated as soon as the eye is brought back into the correct position. Another risk factor is manipulation with instruments in close proximity to the eyeball (24, 25). In the surgical field, instruments should be used with extreme caution and both the surgical drape and the retractor should not touch the eyeball.\u003c/p\u003e \u003cp\u003eRoot apex resection plays an important role in the treatment of dental disease in guinea pigs due to periapical infection and macrodontia. It allows removal of the affected tooth in a much less traumatic way than conventional intraoral extraction and ensures better healing of the alveolus. The described approach also enables the preservation of the socket, which is crucial if it has not been damaged by changes to the tooth tips. This procedure is applicable to both periapical abscesses and non-inflammatory changes (i.e. macrodontia). Due to the high exposure of the eyeball during the procedure and the manipulations within the orbit, adequate protection of the eyeball is required during the procedure and in the postoperative period. In the authors' experience, the opposing mandibular molars must be monitored for clinical crown lengthening, especially in cases where two maxillary molars have been operated on. If this is the case, an apicoectomy of the mandibular second and third molars should also be performed.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthical approval and relevant guidelines: The animals belonged to private owners, and all procedures were carried out for therapeutic purposes, so the work concerns clinical cases and approval from the Institutional Animal Care and Use Committee\u0026nbsp;was not required (Ethical Statement of Wroclaw University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Animal Welfare Advisory Team, 1/2025). All owners provided informed consent for the described procedures and the use of data for publication purposes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication: not applicable\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData availability statement:\u003c/p\u003e\n\u003cp\u003eMore detailed data on patients and diagnostic procedures are available upon contact with the corresponding author: Justyna Ignaszak\u0026ndash;Dziech, [email protected]\u003c/p\u003e\n\u003cp\u003eConflict of interest:\u003c/p\u003e\n\u003cp\u003eI declare that the authors have no competing interests as defined by BMC or other interests that might be perceived to influence the results and/or discussion reported in this paper.\u003c/p\u003e\n\u003cp\u003eFunding:\u003c/p\u003e\n\u003cp\u003eThe APC/BPC is financed by \u0026nbsp;Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland\u003c/p\u003e\n\u003cp\u003eAuthor contribution:\u003c/p\u003e\n\u003cp\u003eJID conceived and the study design, performed diagnostics and surgical procedures and drafted the manuscript. VJ performed diagnostics and surgical procedures, revised the manuscript. TP participated in coordination of the study and revised the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003eAcknowledgement: The research was partly financed by a grant\u0026nbsp;VETUNI Brno 2021ITA15\u003c/p\u003e\n\u003cp\u003eAuthor information (optional): not applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e \u003cli\u003eMaher WP, Johnson RL, Hess J, Steiman HR. Biocompatibility of retrograde filling materials in the ferret canine. Amalgam and IRM. Oral Surg Oral Med Oral Pathol. 1992; doi: 10.1016/0030-4220(92)90021-h.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eHennet P, Girard N. Surgical Endodontics in Dogs: A Review. J Vet Dent 2005; doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1177/089875640502200301\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003e\u003cspan\u003eB\u0026ouml;hmer E. Dentistry in Rabbits and Rodents. USA: John Wiley and Sons; 2015.\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eDziech J, Piasecki T. Anatomical and histological structure of the cavy\u0026rsquo;s teeth as a basis for diagnosis of dental diseases. Med Wet. 2021; doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.21521/mw.6500\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eIgnaszak-Dziech J, Kuropka P, Piasecki T. Histological characteristics of macrodontic cheek teeth of guinea pigs. BMC Vet Res 2023; \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s12917-023-03567-7\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eK\u0026ouml;stlinger S, Witt S, Fehr M. Macrodontia in Guinea Pigs (Cavia porcellus) Radiological findings and localisation in 131 patients. J Exot Pet Med 2021; doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1053/j.jepm.2021.08.002\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eK\u0026ouml;stlinger S, Witt S, Fehr M. Radiological Appearance and Localization of Macrodontia in Guinea Pigs. In: Proceedings of the 3rd International Conference on Avian, Herpetological and Exotic Mammal Medicine, Venice, March 27 to 29 2017. Venice; 2017. S. 614-5\u003c/li\u003e\n \u003cli\u003eGosse H.: Nomina anatomiaca veterinaria. World Association of Veterinary Anatomists 2017.\u003c/li\u003e\n \u003cli\u003eGale Cooper MD, Alan L, Schiller MD. Anatomy of the Guinea Pig. Harvard University Press, 1975\u003c/li\u003e\n \u003cli\u003eJohansen JR. Response of the intermediate plexus of the guinea pig molar to experimental trauma. Acta Odontol Scand. 1970; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3109/00016357009028239\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003ePopesko P, Rajtova V, Horak J. Colour Atlas Of Anatomy Of Small Laboratory Animals. St. Louis, MO, Saunders, 2002\u003c/li\u003e\n \u003cli\u003eMinarikova A, Hauptman K, Jeklova E, Knotek Z, Jekl V. Diseases in pet guinea pigs: a retrospective study in 1000 animals. Vet Rec. 2015 doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/vr.103053\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eO\u0026rsquo;Rouke DP: Disease problems of guinea pigs, in Quesenberry KE, Carpenter JW. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery, St. Louis, MO, Saunders, 2004\u003c/li\u003e\n \u003cli\u003eSchweda MC, Hassan J, B\u0026ouml;hler A, Tichy A, Reiter AM, K\u0026uuml;nzel F. The role of computed tomography in the assessment of dental disease in 66 guinea pigs. Vet Rec. 2014; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/vr.101469\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eMarcy J. Souza, Cheryl B. Greenacre, James S. Avenell, Jonathan S. Wall, Gregory B. Daniel. Diagnosing a Tooth Root Abscess in a Guinea Pig (Cavia porcellus) Using Micro Computed Tomography Imaging. J Exot Pet Med, 2006; Vol 15, Issue 4.\u003c/li\u003e\n \u003cli\u003eCapello V, Cauduro A. Clinical Technique: Application of Computed Tomography for Diagnosis of Dental Disease in the Rabbit, Guinea Pig, and Chinchilla. J Exot Pet Med. 2008; Vol 17, Issue 2.\u003c/li\u003e\n \u003cli\u003eJohansen JR. Response of the intermediate plexus of the guinea pig molar to experimental trauma. Acta Odontol Scand. 1970; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3109/00016357009028239\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eWhite E, Crosse MM. The aetiology and prevention of peri-operative corneal abrasions. Anaesthesia. 1998; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1046/j.1365-2044.1998.00269.x\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eJekl V. Macrodont teeth in guinea pigs. In: Proceedings of the 4th International Conference on Avian, Herpetological and Exotic Mammal Medicine, London, 28th April to 2nd May 2019. London; 2019\u003c/li\u003e\n \u003cli\u003eKliszcz. J 2019 Apicoectomy as an alternative for tooth extraction in guinea pigs. In: Proceedings of the 4th International Conference on Avian, Herpetological and Exotic Mammal Medicine, London, 28th April to 2nd May 2019. London; 2019.\u003c/li\u003e\n \u003cli\u003eLegendre L. Anatomy and Disorders of the Oral Cavity of Guinea Pigs. Vet Clin North Am Exot Anim Pract. 2016; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.cvex.2016.04.006\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eDawson C, Sanchez RF. A prospective study of the prevalence of corneal surface disease in dogs receiving prophylactic topical lubrication under general anesthesia. Vet Ophthalmol. 2016; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/vop.12272\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eBatra YK, Bali IM. Corneal abrasions during general anesthesia. Anesth Analg., 1977; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1213/00000539-197705000-00010\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eGrixti A, Sadri M, Watts MT. Corneal protection during general anesthesia for nonocular surgery. Ocul Surf. 2013; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jtos.2012.10.003\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eAndrew SE. Corneal diseases of rabbits. Vet Clin North Am Exot Anim Pract. 2002; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/s1094-9194(01)00003-2\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003ePark YW, Son WG, Jeong MB, Seo K, Lee LY, Lee I. Evaluation of risk factors for development of corneal ulcer after nonocular surgery in dogs: 14 cases (2009\u0026ndash;2011). J Am Vet Med Assoc. 2013; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.2460/javma.242.11.1544\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n \u003cli\u003eBaum J. Treatment of bacterial ulcers of the cornea in the rabbit: a comparison of administration by eye drops and subconjunctival injections. Trans Am Ophthalmol Soc. 1982. PMID: 6763800.\u003c/li\u003e\n \u003cli\u003eKanda T, Mizoguchi Y, Furumoto K, Shimizu Y, Maeta N, Furukawa T. Effect of Intramuscular Medetomidine Administration on Tear Flow in Rats. Vet Sci. 2020; doi:\u0026nbsp;\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/vetsci7020042\u003c/span\u003e\u003c/span\u003e.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Transorbital, maxilla, apicoectomy, macrodont, abscess, guinea pig, dental disease, malocclusion","lastPublishedDoi":"10.21203/rs.3.rs-6108407/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6108407/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA common cause of teeth malocclusion and feeding disorders in guinea pigs is macrodontia and odontogenic abscesses. If the changes affect the maxillary second or third molar teethwhose apices are located at the base of the orbit, surgical access to them has so far been achieved through enucleation or orbital evisceration. The study aims to demonstrate a transorbital surgical approach to the apices of the maxillary molar teeth (M2 and M3) in guinea pigs, allowing preservation of the eye.\u003c/p\u003e \u003cp\u003eTwenty six apicoectomies of maxillary M2 and M3 were performed. The skin was incised above the dorsal surface of the zygomatic arch below the lower eyelid at the level of the orbicularis oculi muscle. After dissection of the soft tissue, the orbital ligament was incised, and the eye bulbus was displaced dorsolaterally. The blunt dissection of the space between the salivary and zygomatic glands allowed direct access to the affected teeth apices. The apicoectomy was performed with a dental bur. After the procedure, the soft tissues and the eye were approximated back to their original position and the skin was sutured. Recovery was uneventful in all cases. The described method may be applied in cases where it is necessary to perform maxillary second and/or last molar tooth apicoectomy while avoiding damage to the eyeball. Care must be taken to protect the corneal surface of the affected eye.\u003c/p\u003e","manuscriptTitle":"Ventral transorbital apicoectomy of the maxillary second and third molar teeth in guinea pigs (Cavia porcellus): 26 cases","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-01 07:21:33","doi":"10.21203/rs.3.rs-6108407/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"28dd47ec-ef97-4ad3-be9c-f824afa3b0ce","owner":[],"postedDate":"April 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-11-26T08:39:08+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-01 07:21:33","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6108407","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6108407","identity":"rs-6108407","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}