Case Report
Multidisciplinary management of a geminated maxillary central incisor: a case report with six-year follow-up
Weber Schmidt Pereira Lopes, DDS, MS, PhD 1
Mauro Henrique Chagas e Silva, DDS, MS 1
Beatriz Parma Teixeira, DDS 1
Carolinne Maria de Assis Teixeira, DDS 1
Franciele de Paula Matias, DDS 1
Rodrigo R. Amaral, DDS, MS, PhD 2
https://doi.org/10.71347/alx571ic5
1 Associação Brasileira de Odontologia, Juiz de Fora, Minas Gerais, Brazil.
2 Department of Endodontics, Nova Southeastern University, College of Dental Medicine, Fort Lauderdale, Florida, USA.
Corresponding author:
Rodrigo R. Amaral, DDS, MS, PhD
Associate Prof. Department of Endodontics,
Nova Southeastern University, College of Dental Medicine,
3200 South University Drive, Fort Lauderdale, Florida, 33328, USA Phone number: +1(954)262-1757 / Email: rrodrig6@nova.edu
Key words: Case report, dental anomalies, dental gemination, orthodontic treatment, root canal treatment.
Acknowledgements: The authors deny any conflict of interest related to this study.
The patient’s guardian provided informed consent.
Abstract
Gemination is a rare morphoanatomical alteration that may lead to aesthetic, functional, and orthodontic issues. This study presents a clinical case of multidisciplinary treatment of a geminated maxillary central incisor. A 12-year-old patient presented with aesthetic concerns due to gemination in the left maxillary central incisor, dental agenesis, and malocclusion. Root canal treatment was performed using an operating dental microscope, an apex locator, and motor-driven instruments, which were essential for facilitating the planned aesthetic and orthodontic procedures. Clinical and radiographic follow-ups conducted six years and three months after treatment revealed no clinical or radiographic signs or symptoms, indicating success in all endodontic, orthodontic, and aesthetic outcomes. Restoring the aesthetics had a positive impact on patient ́s psychosocial well-being, self-esteem, confidence, and social interactions. Accurate diagnosis and the role of each area in the multidisciplinary approach are crucial for achieving long-term success in treating dental gemination.
Clinical Relevance: Accurate diagnosis and multidisciplinary planning are crucial for achieving long-term success in treating dental gemination.
Introduction
Fusion and gemination are rare and similar morphoanatomical anomalies, with a prevalence of less than 1%, occurring more frequently in deciduous dentition and most commonly involving incisors and canines (Steinbock et al., 2014; Tsesis et al., 2004). Differentiating between these conditions is challenging and depends on counting the number of teeth in the dental arch and a radiographic examination. (Wong 2001; Altug-Atac and Erdem 2007). Fusion can occur between two normal teeth or involve a supernumerary tooth (Spatafore 1992). In contrast, gemination occurs during odontogenesis as an incomplete attempt to divide a single dental germ, resulting in a bifid crown without altering the tooth count in the arch. It differs from fusion by showing a single pulp chamber and a single root canal (Spatafore 1992).
Both conditions are generally asymptomatic and may not require treatment (Tsesis et al., 2004). However, maintaining hygiene becomes more challenging when the crown’s groove or division extends subgingivally. This increases the risk of caries and periodontal disease, which may require intervention (Wong 2001). Furthermore, the macrodontia caused by fusion or gemination can lead to dental crowding, malocclusions, and aesthetic concerns. Multidisciplinary approaches are often necessary to effectively address these issues, as they can significantly impact children’s self-esteem and emotional development (Shaw et al., 1980; Davis et al., 1998).
Anatomical anomalies like these can complicate endodontic treatment both biologically and mechanically. Ignoring these complexities may jeopardize treatment success by allowing primary or persistent infections from microorganisms to colonize the root canal (Tsesis et al., 2004, Braun et al., 2003). Given the presence of a geminated left maxillary central incisor and significant aesthetic concerns, this case discloses a clinical case that underwent multidisciplinary treatment, including endodontic, orthodontic, and restorative procedures.
Case report
A 12-year-old male patient was referred for dental evaluation due to concerns about aesthetics and functionality. The patient had no history of medications, systemic diseases, or any relevant genetic information. The primary concerns were aesthetics and bullying at school. Clinically, the patient exhibited mixed dentition, malocclusion, an overbite, a convex profile with an underdeveloped maxilla, crowding, an anterior open bite, and macrodontia in the left maxillary central incisor (Fig. 1A-1E). Radiographic examination revealed that the macrodontia resulted from gemination, characterized by a single bifid crown, a single root, and a single root canal (Fig. 1F, 1G). A multidisciplinary team of orthodontic, endodontic, and restorative specialists was essential for effective treatment planning and execution.
The patient’s guardian signed the informed consent after discussing the clinical approach, treatment plan, and prognosis for this multidisciplinary case.
Orthodontic treatment
The patient exhibited an Angel Class I occlusion during the late mixed dentition stage, characterized by crowding in both the upper and lower teeth and insufficient space for the upper first premolars. An anterior crossbite was observed, involving the upper right lateral incisor in occlusion with the lower right central incisor, in addition to an anterior deep bite and an atretic arch. The orthodontic treatment aimed to reduce significant lip retraction and mandibular retrusion, alleviate crowding, expand the maxilla, correct the anterior open bite, and adjust the mandibular planes to promote proper alignment and leveling, enhancing the patient’s aesthetic outcome. The first upper and lower premolar teeth were extracted. The procedure lasted six years and three months. The extended duration of the treatment was affected by the complexity of the case, the patient’s level of compliance with prescribed instructions, and considerations related to the patient’s growth and development. These factors collectively influenced the pace and progression of the treatment, ultimately leading to the desired result.
Endodontic treatment
Root canal treatment (RCT) of the left maxillary central incisor was performed for prosthetic reasons, necessitated by crown sectioning and reshaping to adjust tooth proportions and alignment within the arch. Initially, the tooth presented with a carious lesion on the cingulum, responded positively to pulp sensibility tests, and showed no periradicular lesions on periapical radiographs (Fig. 2A). RCT included infiltrative local anesthesia, rubber dam isolation, and disinfection using 3% hydrogen peroxide and 5.25% sodium hypochlorite (NaOCl). The access cavity was prepared with diamond burs in a high-speed handpiece under magnification (8x) using a dental operating microscope (Opto DM, São Carlos, SP, Brazil). Root canal instrumentation involved Gates-Glidden burs and K-files, adopting a crown-down approach. The working length was determined with an electronic apex locator NovApex, Forum Technologies, Rishon Le-zion, Israel) and confirmed radiographically. Two instrumentation pathways, one mesially and one distally, were utilized due to the elongated oval canal, which featured significant buccolingual flattening and an elliptical mesiodistal shape that converged into a single foramen.
Irrigation with 5.25% NaOCl was performed after each change of instrument. Final canal shaping employed a ProTaper Universal F4 file (Dentsply Maillefer, Ballaigues, Switzerland). Final irrigation was performed using 5 mL of NaOCl, followed by passive ultrasonic agitation (PUI) for 1 minute in three 20-second cycles with the E1-Irrisonic tip (Helse Ultrasonic, Santa Rosa de Viterbo, SP, Brazil). To remove the smear layer, a final rinse with 17% EDTA for 3 minutes, followed by 5.25% NaOCl was performed before drying the canal with capillary tips and sterile paper points. Obturation employed the thermoplasticized warm vertical condensation technique using Pulp Canal Sealer EWT (SybronEndo, Orange, CA, USA) and accessory gutta-percha cones. Radiographs confirmed a uniform root canal filling (Fig. 2B, 2C).
Fig. 1. A - Anterior occlusal view. B - Right profile occlusal view. C - Left profile occlusal view. D - Total view of the maxillary teeth. E - Total view of the mandibular teeth. F - Initial periapical radiograph of the geminated upper central incisor. G - Initial frontal image of the patient.
Fig. 2. A- Initial periapical radiograph of the geminated upper central incisor. B- Final periapical radiograph after root canal obturation of the geminated upper central incisor. C- Final periapical radiograph after coronal sealing of the endodontically treated geminated upper central incisor. D- View of the initial phase of orthodontic appliance assembly.
Restorative procedures
The cavity access was sealed with Filtek Z350 XT composite resin (3M ESPE, St Paul, MN USA). Distal crown sectioning and root reshaping were performed to enhance the aesthetic appearance, followed by gingivoplasty to improve smile harmony. After gingival healing, Filtek Z350 XT composite resin restorations were used to restore the anterior teeth, achieving proportional harmony (Fig. 3A- 3F). Initial shade selection was performed with moist teeth under natural lighting using FiltekTM shades tab (3M ESPE, St Paul, MN, USA). The teeth were etched with Ultra Etch, a 35% phosphoric acid solution (Ultradent Products, South Jordan, USA), for 15 seconds only on the enamel, and then rinsed with air/water jets. The Single Bond Universal adhesive system (3M ESPE, St. Paul, MN, USA) was applied to the dentin walls using applicators (Microbrush, Kg Sorensen), and their excess was removed with gentle air drying for 5 seconds, followed by photoactivation for 20 seconds. Each increment of composite resin was photoactivated for 20 seconds, and upon completion of the restoration, final photoactivation was performed for an additional 40 seconds. No mock-ups or silicone guides were used in this case, just hands-free. A follow-up conducted six years and three months later confirmed the successful treatment (Fig.4A- 4E).
Discussion
In this case, the diagnosis was identified as gemination, as the division of the germ occurred only at the crown level. This resulted in a bifid crown that did not extend to the root. The tooth had a single root with a wide root canal. The arch contained the complete number of teeth, with no missing or extra teeth. Occasionally, cases of macrodontia in anterior teeth caused by gemination or fusion are encountered in dental practice (Steinbock et al., 2014, Altug-Atac and Erdem 2007). The lack of proper dental proportion, especially in the front teeth, can be aesthetically unappealing (Braun et al., 2003).
Additionally, fused or geminated teeth can cause crowding, periodontal disease, dental caries, and disruption in the eruption of adjacent teeth (Vieira et al., 2012). The extraction of the geminated tooth, followed by dental implant placement, was not considered because reducing the crown to achieve a proportionate size is the preferred method for treating macrodontia. Whenever feasible, dentists should strive to avoid extractions, as implants are not suitable for young patients until their permanent teeth have fully erupted and skeletal growth is complete (Thilander et al., 1994).
Longitudinal sectioning of a macrodont can expose the pulp chamber, requiring prior endodontic treatment to prevent the development of endodontic disease (Sjögren et al., 1990). Success rates for endodontic treatment are closely linked to the initial pulp diagnosis. In vital teeth, single-session endodontic therapy offers advantages by preventing microbial contamination that may compromise treatment success (Ricucci et al., 2012; Friedman and Mor 2004; Figini et al., 2008; Sjögren et al., 1997; Trope et al., 1999). In this case, the decision for single- session therapy was based on pulp vitality, patient availability, and appropriate resources.
Effective disinfection depends on understanding anatomical structures. Failing to account for complex or atypical anatomy in unusual teeth can lead to treatment failure. (Tsesis et al., 2004, Davis et al., 1998). Modern technologies, such as dental operating microscopes and cone-beam computed tomography (CBCT), aid in visualizing complex cases. (Song et al., 2010; Martins et al.,2014;AlShaikhly;Pateletal.,2019).While CBCT was unavailable during treatment, the use of periapical radiography, combined with an apex locator, provided reliable anatomical information.
The geminated incisor had an oval-shaped canal
with significant buccolingual flattening. Two distinct instrumentation paths were utilized to thoroughly clean and shape the root canal walls. Areas untouched by mechanical instrumentation may harbor microorganisms, leading to perpetuating infections and treatment failure (Thilander et al., 1994; Sjögren et al., 1990; Ricucci et al., 2011; Sjögren et al., 1997). Utilizing mechanical shaping alongside chemical irrigation, particularly with 5.25% sodium hypochlorite (NaOCl), ensures effective canal cleaning. (Gonçalves et al., 2016; Ruksakiet et al., 2020 Xu et al., 2022).
Goerig et al. (1982) introduced a step- down instrumentation technique for efficient cleaning and irrigation. Based on step-down principles, this approach remains a recommended endodontics technique (Goerig et al., 1982; Del Bello et al., 2003; Silveira et al., 2008). A hybrid instrumentation protocol combined manual techniques with ProTaper Universal F4 rotary files to achieve optimal canal shaping (Riitano 2005; Barbizam et al., 2002; Cheung and Liu 2009; Ruddle 2002).
Fig. 3. A-C: Photographs of orthodontic treatment progress - maintenance of prosthetic space. A-Intraoral frontal. B- Intraoral right profile. C-Intraoral left profile. D-F: Final intraoral photographs after the removal of orthodontic fixed appliances and aesthetic restorative treatment. D- Intraoral frontal. E-Intraoral right profile. F-Intraoral left profile.
For obturation, a thermoplasticized warm vertical compaction technique was used with Pulp Canal Sealer, which was chosen for its favorable physical-chemical properties and antimicrobial potential (Schilder 1967; Al-Dewani et al., 2000; Gerosa et al., 1995; Heling and Chandler 1996; Chang et al., 2015).
One of the most significant challenges of this case was related to the anatomical characteristics of the geminated tooth. Irrigation activated by an ultrasonic tip was used to improve disinfection and reduce the bacterial load. Studies related to cleaning alongated oval-shaped root canals have demonstrated the importance of maximizing cleaning in anatomical areas that instruments do not reach, thereby improving the disinfection of the root canal system (Siqueira et al., 2013; Amaral et al., 2020). Unprepared areas can harbor microorganisms, which can jeopardize the success of root canal treatment (Siqueira et al., 2018). Restoring the aesthetics, function, and occlusion of patients with macrodontia presents a significant challenge.
Fig. 4. A- Initial periapical radiograph of the geminated upper central incisor. B- Final periapical radiograph after endodontic treatment. C- Follow-up radiograph 6 years after endodontic and multidisciplinary treatment. D- Frontal image of the patient before multidisciplinary treatment. E- Frontal image of the patient after 6 years of follow-up, multidisciplinary treatment.
Orthodontic treatment was crucial for improving malocclusion and maintaining prosthetic spaces for aesthetic composite resin restorations. Periodontal health was restored through root reshaping and gingivoplasty. The multidisciplinary approach proved essential in managing this complex case. The size of the teeth significantly influenced the patient’s decision to seek treatment. Aesthetically displeasing smiles can have psychosocial effects, impacting self-esteem, confidence, and social interactions (Davis et al., 1998). Multidisciplinary treatment of dental-facial anomalies must address psychological factors that can lead to emotional distress (Shaw et al., 1980; Davis et al., 1998). These concerns were evident in this patient.
The rarity of this dental anomaly indicates that there are few case reports in the literature (Steinbock et al., 2014; Tsesis et al., 2004; Wong 2001; Altug-Atac and Erdem 2007) regarding the multidisciplinary treatment of geminated maxillary central incisors, particularly emphasizing endodontics and long- term follow-up.
Conclusion
This case underscores the importance of meticulous multidisciplinary planning, evidence-based protocols, and the careful execution of treatment to achieve long-term clinical success.
Al Shaikhly B, Harrel SK, Umorin M, Augsburger RA, Jalali P. Comparison of a dental operating microscope and high-resolution videoscope for endodontic procedures. J Endod. 2020;46(5):688–93.
Al-Dewani N, Hayes SJ, Dummer PM. Comparison of laterally condensed and low-temperature thermoplasticized gutta-percha root fillings. J Endod. 2000;26(12):733–8.
Altug-Atac AT, Erdem D. Prevalence and distribution of dental anomalies in orthodontic patients. Am J Orthod Dentofacial Orthop. 2007;131(4):510–4.
Amaral RR, Oliveira AGG, Braga T, et al. Quantitative Assessment of the Efficacy of Two Different Single-file Systems in Reducing the Bacterial load in Oval-Shaped Canals: A Clinical Study. J Endod 2020;46:1228–34
Barbizam JVB, Fariniuk LF, Marchesan MA, Pecora JD, Sousa-Neto MD. Effectiveness of manual and rotary instrumentation techniques for cleaning flattened root canals. J Endod. 2002;28(5):365–6.
Braun A, Appel T, Frentzen M. Endodontic and surgical treatment of a geminated maxillary incisor. Int Endod J. 2003;38(6):380–6.
Chang SW, Lee YK, Zhu Q, Shon WJ, Lee WC, Kum KY, et al. Comparison of the rheological properties of four root canal sealers. Int J Oral Sci. 2015;7(1):56–61.
Cheung GS, Liu CS. A retrospective study of endodontic treatment outcome between nickel-titanium rotary and stainless steel hand filing techniques. J Endod. 2009;35(7):938–43.
Davis LG, Ashworth PD, Spriggs LS. Psychological effects of aesthetic dental treatment. J Dent. 1998;26(7):547–54.
Del Bello TPDL, Wang N, Roane JB. Crown-down tip design and shaping. J Endod. 2003;29(8):513–8.
Figini L, Lodi G, Gorni F, Gagliani M. Single versus multiple visits for endodontic treatment of permanent teeth: a Cochrane systematic review. J Endod. 2008;34(9):1041–7.
Friedman S, Mor C. The success of endodontic therapy—healing and functionality. J Calif Dent Assoc. 2004;32(6):493–503.
Gerosa R, Menegazzi G, Borin M, Cavalleri G. Cytotoxicity evaluation of six root canal sealers. J Endod. 1995;21(9):446–8.
Goerig AC, Michelich RJ, Schultz HH. Instrumentation of root canals in molar using the step-down technique. J Endod. 1982;8(12):550–4.
Gonçalves LS, Rodrigues RCV, Junior CVA, Soares RG, Vettore MV. The effect of sodium hypochlorite and chlorhexidine as irrigant solutions for root canal disinfection: a systematic review of clinical trials. J Endod. 2016;42(4):527–32.
Heling I, Chandler NP. The antimicrobial effect within dentinal tubules of four root canal sealers. J Endod. 1996;22(5):257–9.
Martins JN, Marques D, Mata A, Caramês J. Clinical efficacy of electronic apex locators: systematic review. J Endod. 2014;40(6):759–77.
Patel S, Brown J, Pimentel T, Kelly RD, Abella F, Durack C. Cone beam computed tomography in Endodontics—a review of the literature. Int Endod J. 2019;52(8):1138–52.
Ricucci D, Russo J, Rutberg M, Burleson JA, Spångberg LS. A prospective cohort study of endodontic treatments of 1,369 root canals: results after 5 years. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;112(6):825–42.
Riitano F. Anatomic Endodontic Technology (AET)—a crown-down root canal preparation technique: basic concepts, operative procedure and instruments. Int Endod J. 2005;38(8):575–87.
Ruddle CJ. The ProTaper endodontic system. Endod Pract. 2002;5(3):34–44.
Ruksakiet K, et al. Antimicrobial efficacy of chlorhexidine and sodium hypochlorite in root canal disinfection: a systematic review and meta-analysis of randomized controlled trials. J Endod. 2020;46(8):1032–41.
Schilder H. Filling root canals in three dimensions. Dent Clin North Am. 1967;11(3):723–44.
Shaw WC, Addy M, Ray C. Dental and social effects of malocclusion and effectiveness of orthodontic treatment: a review. Community Dent Oral Epidemiol. 1980;8(1):36–45.
Silveira LFM, Martos J, Pintado LS, Teixeira RA, Neto JBC. Early flaring and crown-down shaping influences the first file bind to the canal apical third. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;106(1):99–101.
Siqueira JF Jr, Alves FR, Versiani MA, et al. Correlative bacteriologic and micro-computed tomographic analysis of mandibular molar mesial canals prepared by self-adjusting file, reciproc, and twisted file systems. J Endod 2013;39:1044–50.
Siqueira JF Jr, Rôças IN, Marceliano-Alves MF, et al. Unprepared root canal surface areas: causes, clinical implications, and therapeutic strategies. Braz Oral Res 2018;32:1–19.
Sjögren U, Figdor D, Persson S, Sundqvist G. Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J. 1997;30(5):297–306.
Sjögren U, Hägglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. J Endod. 1990;16(10):498–504.
Song CK, Chang HS, Min KS. Endodontic management of supernumerary tooth fused with maxillary first molar by using cone-beam computed tomography. J Endod. 2010;36(11):1901–4.
Spatafore CM. Endodontic treatment of fused teeth. J Endod. 1992;18(12):628–31.
Steinbock N, Wigler R, Kaufman AY, Lin S, Abu-El Naaj I, Aizenbud D. Fusion of central incisors with supernumerary teeth: a 10-year follow-up of multidisciplinary treatment. J Endod. 2014;40(7):1020–4.
Thilander B, Ödman J, Gröteborg K, Friberg B. Osseointegrated implants in adolescents: an alternative in replacing missing teeth?. Eur J Orthod. 1994;16(2):84–95.
Trope M, Delano EO, Orstavik D. Endodontic treatment of teeth with apical periodontitis: single vs. multivisit treatment. J Endod. 1999;25(5):345–50.
Tsesis I, Steinbock N, Rosenberg E, Kaufman AY. Endodontic treatment of developmental anomalies in posterior teeth: treatment of geminated/fused teeth—report of two cases. Int Endod J. 2003;36(5):372–9.
Vieira AR, Siqueira JF Jr, Ricucci D, Lopes WS. Dentinal tubule infection as the cause of recurrent disease and late endodontic treatment failure: a case report. J Endod. 2012;38(2):250–4.
Wong M. Treatment considerations in a geminated maxillary lateral incisor. J Endod. 1991;17(4):179–81.
Xu H, et al. Effects of concentration of sodium hypochlorite as an endodontic irrigant on the mechanical and structural properties of root dentine: a laboratory study. Int Endod J. 2022;55(10):1091–102.