1 Volume 24 2025 e259468 Case Report Braz J Oral Sci. 2025;24:e259468http://dx.doi.org/10.20396/bjos.v24i00.8679468 1 DDS, MSc, PhD, Dental School, Federal University of Pelotas (UFPel), Pelotas, Rio Grande do Sul, Brazil. 2 DDS, MSc student, Dental School, Federal University of Pelotas (UFPel), Pelotas, Rio Grande do Sul, Brazil. 3 DDS, MSc, PhD, School of Dentistry, Department of Cariology, Restorative Sciences and Endodontics, University of Michigan, Ann Arbor, MI, USA. 4 DDS, MSc, PhD, Dental School, Federal University of Pelotas (UFPel), Pelotas, Rio Grande do Sul, Brazil. Corresponding author: Prof. Nadia de Souza Ferreira. Faculdade de Odontologia, Universidade Federal de Pelotas. 457 Gonçalves Chaves Street, Pelotas, RS, Brazil. CEP: 96015-560. E-mail: nadia.ferreira@ufpel.edu.br Editor: Dr. Altair A. Del Bel Cury Received: March 23, 2025 Accepted: July 14, 2025 Root canal treatment of a maxillary lateral incisor with type II Dens Invaginatus: a case report Lucas Pinto Carpena¹ , Gabriel Lima Braz2 , Lucas Peixoto de Araújo3 , Nádia de Souza Ferreira4* Aim: To report a case of endodontic treatment of an upper lateral incisor with type II Dens Invaginatus with the aid of operative microscopy and ultrasonic tips. Case Report: A 16 years-old female patient was referred for endodontic treatment of the left maxillary lateral incisor with diagnosis of symptomatic apical periodontitis and type II Dens Invaginatus. Removal of the intracanal calcified structure was carried out using long-shaft high-speed drills in conjunction with diamond-coated ultrasonic tips. Instrumentation was performed alternating between reciprocating and manual files up to the K 80 file. Intracanal medication based on 2% chlorhexidine gel and calcium hydroxide powder remained inside the canal for 14 days. Filling was executed by creating an apical plug with bioceramic sealer (Bio-C Repair, Angelus) and a Mineral trioxide aggregate (MTA, Angelus) backfill up to the cervical third. In the 14 months follow-up the periapical radiograph and CBCT showed signs of periapical bone repair. Conclusion: This report highlights the critical role of CBCT and the use of UT combined with microscopy in comprehensive treatment planning and execution. Additionally, it provides valuable clinical evidence demonstrating the feasibility and effectiveness of this approach. Keywords: Dens in dente. Tooth abnormalities. Ultrasonics. Case reports as topic. https://orcid.org/0000-0002-3384-6016 https://orcid.org/0009-0009-4858-562X https://orcid.org/0000-0003-2893-1416 https://orcid.org/0000-0002-5123-5657 2 Carpena et al. Braz J Oral Sci. 2025;24:e259468 Introduction Dens invaginatus (DI) is a dental anomaly characterized by a deep invagination of the coronal or root surface of the tooth delimited by the enamel itself1. The pre- cise etiology of DI remains unknown, with authors lacking consensus; however, a multifactorial origin is suggested, involving genetic factors and external influ- ences during tooth development2. The permanent upper lateral incisors are the most involved teeth3-5. Clinically, the affected teeth can exhibit an unconventional crown anatomy in vari- ous shapes. The presence of an enlarged cingulum and deep palatal groove or fora- men coecum are also reported, however diagnosis is mainly carried out through imaging examinations, radiographically it is possible to visualize the shape of the invagination eventually surrounded by an radiopaque enamel border6-8. When the enamel covering the invagination is naturally absent, it can function as a plaque retention factor. As bacteria and their by-products spread through the invagination, crossing the dentinal tubules, they can reach the dental pulp and trigger pathologies such as pulpitis, pulp necrosis, and periapical diseases. Consequently, endodontic treatment becomes imperative9. Given the wide anatomical variability observed in such cases, modifications to con- ventional endodontic therapy are often necessary, posing a technical challenge for endodontists and general clinicians10. This paper aims to report and describe a clinical case of endodontic treatment of an upper lateral incisor with DI employing operative microscopy and ultrasonic tips (UT). Case Report This case report was conducted according to the PRICE guidelines for case reports in endodontics, a flowchart containing case details and an appropriate checklist were provided (Figure 1)11. Informed consent was obtained prior to the submission of this study in line with the ICMJE Protection of Research Participants policy. 3 Carpena et al. Braz J Oral Sci. 2025;24:e259468 Figure 1. PRICE 2020 Flowchart A 16 years-old female patient from south Brazil, presented with pain in the left max- illary lateral incisor area. The patient did not present any systemic health issues. Clinically, the referred tooth presented a common anatomy, and no carious lesions were observed (Figure 2). After a negative response to the cold test, an intraoral periapical digital radiographic (CDR Elite size 2, Dentsply Sirona, Charlotte, NC, USA) revealed a deep invagination of calcified tissue extending through the root, with no communication with the periodontium, compatible with type II DI, with an 4 Carpena et al. Braz J Oral Sci. 2025;24:e259468 associated radiolucent periapical lesion (Figure 3). A high-resolution cone-beam computed tomography (CBCT) (Eagle Edge 0.2 FS) was obtained with a small FOV (5x5 cm) and voxel size of 0.075 mm. CBCT revealed a hypodense apical lesion and confirmed Dens Invaginatus (Figure 4). Therefore, diagnosis of pulp necrosis and symptomatic apical periodontitis was established, and non-surgical endodontic treatment was agreed upon as the treatment plan. Figure 2. Initial clinical presentation of the case Figure 3. Initial periapical radiograph 5 Carpena et al. Braz J Oral Sci. 2025;24:e259468 Figure 4. Initial cone beam computed tomography (CBCT) During the clinical procedure, local anesthesia with lidocaine with 1:100:000 epi- nephrine (Alphacaine 2%, Nova DFL, Rio de Janeiro, Brazil) and rubber dam isola- tion were performed. From this point on, the procedure was carried out with the aid of microscopic using 4 up to 25 zoom magnification (OPMI Pico, Zeiss, Ober- kichen, Germany) Using long-shaft high-speed drills associated with the FlatSonic UT (Helse Ultrasonic, São Paulo, Brazil) it was possible to obtain coronal access followed by removal of the intracanal calcified structure, thereby connecting the root canal and the invagination (Figure 5). The root canals length measures were determined electronically by a RomiApex A-15 apex locator (Romidan LTD, Kiryat Ono, Israel). Working length was established at the “0.0” reading of the electronic apex locator. The root canal was instrumented using the foraminal enlargement technique with reciprocating files using a Reciproc R50 file (VDW GmbH) along with manual files (Maillefer/Dentsply, Ballaigues, Switzerland) up to the K 80 file, 2% chlorhexidine gel associated with physiological saline solution was used for irrigation. After chemical-mechanical preparation, intracanal medication (ICM) based on 2% chlorhexidine gel and calcium hydroxide was placed and remained inside the root canal for 14 days. 6 Carpena et al. Braz J Oral Sci. 2025;24:e259468 Figure 5. Removal of the intracanal calcified structure connecting the root canal and the invagination In the second appointment, ICM removal and final irrigation were done with six 20 seconds cycles of passive ultrasonic irrigation (PUI), using the E1-Irrisonic tip (Helse Ultrasonics, São Paulo, Brazil). The initial three cycles used with physiological saline solution, while the subsequent ones involved the use of Ethylenediaminetetraacetic Acid (EDTA). Filling was performed by creating an apical plug with bioceramic sealer (Bio-C Repair, Angelus, Brazil) and Mineral trioxide aggregate (MTA) backfill up to the cervical third. Finally, the tooth was restored with bulk-fill composite resin (Figure 6). Figure 6. Root canal filling with an apical plug (Bio-C Repair, Angelus, Brazil) and Mineral trioxide aggregate (MTA). 7 Carpena et al. Braz J Oral Sci. 2025;24:e259468 Clinical and radiographic follow-up were carried out at 30 and 90 days, where the patient was found asymptomatic and with initial signs of periapical repair. A periapical radiograph and CBCT were performed 14 months after the procedure (Figures 7 and 8) demonstrates suggestive signs of periapical bone repair and, therefore, the success of the endodontic treatment. Figure 7. Radiographic follow-up after 14 months Figure 8. CBCT follow-up after 14 months. 8 Carpena et al. Braz J Oral Sci. 2025;24:e259468 Discussion Endodontic treatment of DI is complex and determining an effective treatment plan depends on numerous factors, especially the anatomical variations present. Oehlers’s widely used classification divides DI into three types: I) invagination limited to the crown; II) invagination extends through the root without communication with the periodontium; III) invagination extending through the entire root, opening into the periodontal ligament, either laterally (IIIa) or apically (IIIb), resulting in an additional foramen12. In the present case, imaging suggesting the presence of intracanal cal- cified tissue that ended before the apical foramen was crucial for its classification as a type II DI. Periapical radiographs can produce valuable but limited information in such cases. Therefore, when DI or a complex canal morphology is suspected, requesting a CBCT should be strongly considered, as it provides substantially more information about the internal root anatomy, allowing for the accurate classification of DI and its peri- radicular status9,13,14. In this case, CBCT was instrumental in assessing the extent of the invagination and planning the path and depth of penetration before endodontic treatment, ensuring a more precise approach. For teeth with DI and necrotic pulps or irreversible pulpitis, treatment options include non-surgical endodontic treatment, apical surgery, guided endodontics or extraction. Due to the extensive anatomical variability in DI, clinical decision-making must be tai- lored to each case15-17. When opting for a conventional endodontic treatment, adapta- tions for the conventional technique are often necessary. In type II DI cases, a viable approach involves uniting the main canal and the invagination using diamond-coated UT; however, this technique remains scarcely documented in the literature10. In the present case, UT combined with microscopic magnification were employed to cre- ate a single, widened root canal by removing obstructions and calcifications, increas- ing canal volume and surface area, and optimizing instrumentation by minimizing non-instrumented regions18. Additionally, ultrasound was used to activate the irrigating solution, enhancing its effectiveness. The application of PUI improves root canal disinfection compared to conventional irrigation methods19 and has also been shown to reduce the risk of postoperative pain within the first 24 hours20. For root canal sealing and to promote optimal repair conditions for the apical periodontium, an apical barrier was created following instrumentation. A bioceramic sealer was selected as the material for the plug, a technique that has been successfully reported in the litera- ture21. As a bioactive material composed mainly of calcium and silicate elements, bioceramic sealers have the ability to induce regeneration of both cementum and the periodontal ligament22. The success of the endodontic intervention in this case is supported by the 14-month follow-up, during which the tooth remained asymptomatic and showed radiographic and tomographic evidence of periapical repair. This case highlights the critical role of CBCT and the use of UT combined with microscopy in com- prehensive treatment planning. Additionally, it provides valuable clinical evidence demonstrating the feasibility and effectiveness of this approach. Nevertheless, 9 Carpena et al. Braz J Oral Sci. 2025;24:e259468 long-term clinical and radiographic monitoring remains essential to ensure the sustained success of the treatment. Conflict of Interest The authors declare no conflict of interest. Acknowledgment The authors declare that there was no funding for this study. Data availability Datasets related to this article will be available upon request to the corresponding author. Institutional Review Board Statement This case report received approval from the local ethics committee (CAAE: 90621025.7.0000.5318) Informed Consent Statement A signed informed consent form was obtained from the patient, authorizing the use of clinical information and images for publication purposes. Author Contribution Lucas Pinto Carpena: Conceptualization; Data curation; Methodology; Writing - original draft; and Writing - review & editing. (ICMJE’S criteria: I; II; III; IV). Gabriel Lima Braz: Methodology, Data curation; Writing - original draft; and Writing - review & editing. (ICMJE’S criteria: I; II; III; IV). Lucas Peixoto de Araújo: Data curation; Methodology; Validation; Supervision; Writing - review & editing. (ICMJE’S criteria: I; II; III; IV). Nádia de Souza Ferreira: Conceptualization; Data curation; Methodology; Validation; Supervision; Roles/Writing - original draft; and Writing - review & editing. (ICMJE’S criteria: I; II; III; IV). All authors have had significant participation in the production of this manuscript, in alignment with the ICMJE recommendations: i) Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; ii) Drafting the work or revising it critically for important intellectual content; iii) Final approval of the version to be published; and iv) Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. References 1. Zhu J, Wang X, Fang Y, Von den Hoff JW, Meng L. An update on the diagnosis and treatment of dens invaginatus. 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