Teeth: A Report of Two Cases
Mouna Ben Salem ,1,2Farah Chouchene ,1,2Fatma Masmoudi ,1,2Ahlem Baaziz ,1,2 Fethi Maatouk ,1,2and Hichem Ghedira 1,2
1Pediatric and Preventive Dentistry Department, Faculty of Dental Medicine of Monastir, Monastir, Tunisia
2ABCDF Laboratory of Biological, Clinical and Dento-Facial Approach, University of Monastir, Monastir, Tunisia Correspondence should be addressed to Mouna Ben Salem; firstname.lastname@example.org
Received 28 December 2020; Revised 6 May 2021; Accepted 15 May 2021; Published 2 June 2021 Academic Editor: Leandro Napier de Souza
Copyright © 2021 Mouna Ben Salem et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Primary double teeth (PDT), referring to either gemination or fusion, are one of the most important and frequent developmental dental anomalies that can aﬀect children’s oral health. Many clinical complications are correlated with these anomalies, such as dental caries, malocclusions, periodontal problems, and dental anomalies in permanent dentition. The aim of this report was to describe, through two cases, a case of gemination and another of fusion, the clinical management, the consequent eﬀects, and the possible repercussions of these two developmental abnormalities on permanent successors. The ﬁrst case involved gemination of the primary maxillary left central incisor (#61) in a 6-year-old boy. The patient presented with dental caries in the geminated tooth and its contiguous primary left lateral incisor (#62). The radiological examination revealed a slight developmental delay in the permanent left lateral incisor (#22). The treatment plan involved performing a pulpotomy and restoring the dental crowns of the aﬀected teeth. The second clinical case describes a 6-year-old girl with unilateral fusion between a primary mandibular lateral incisor (#72) and a supernumerary tooth (#72’). The treatment included restoration of the deep grooves of the fused teeth usingﬂowable composite and coronal restoration of the contiguous left primary canine (#73).
Clinical and radiological follow-ups were performed every 3 months to monitor the development of teeth. No clinical and radiological symptoms were noted during the follow-up visits. PDT may require a multidisciplinary treatment. They should be diagnosed early to avoid and treat any possible complications in both the primary teeth and their permanent successors.
Developmental dental anomalies may include abnormalities in teeth number, size, shape, structure, and position . Only few studies have reported the frequency of these develop- mental dental hard tissue anomalies in primary dentition.
As reported in the literature, their prevalence ranges from 0.5% to 7% . However, Folayan et al.  found a preva- lence of 8.2% in 3 to 5-year-old Nigerian children in 2019.
Primary double teeth (PDT), often referring to both fusion and gemination, are described as one of the most frequent developmental dental anomalies in primary dentition [2–4].
Unlike tooth fusion which is deﬁned as the union between the enamel or both dentin and enamel of two or more separate
developing tooth buds , gemination is known as an attempt of a single tooth bud to divide. Fusion has usually been con- fused with gemination, especially if it includes a supernumer- ary tooth . Primary fused teeth (PFT) are more frequently observed in primary than in permanent dentition . PFT are mostly found unilaterally .
Double teeth are commonly reported in the anterior region and most often include mandibular lateral incisors and canines . Diagnosis of this phenomenon mainly depends on the case history, as well as the clinical and radio- graphic examinations.
Clinically, PFT can present a crown of double size or a biﬁd crown, or have a normal tooth size. Radiographically, their expression can range from two separate roots to a single
root depending on the developmental phase of the fused teeth buds. However, clinically, geminated teeth appear as two fully or partially separated crowns, and radiographically, they result in a single root and root canal .
A variety of clinical complications have been reported in PDT, including caries formation in the groove between the fused crowns, tooth impaction, malocclusions, and esthetic problems .
Currently, three treatment options are suggested for PDT, involving preventive measures, a restorative approach after caries excavation, or a surgical procedure (extraction) .
Many studies have illustrated the impact of fused primary teeth on permanent dentition, including aplasia, hyperodon- tia, and double teeth formation [4, 9].
The present report describes the management of two cases, a ﬁrst case of unilateral gemination in the primary maxillary left central incisor in a six-year-old boy and a sec- ond one of unilateral fusion of a supernumerary tooth with a primary mandibular left lateral incisor in a six-year-old girl.
2. Case Presentation
2.1. Case Report 1. A 6-year-old Tunisian boy presented to the Pediatric and Preventive Dentistry Department at the Faculty of Dental Medicine of Monastir with a chief com- plaint of dental caries on the primary maxillary left central incisor (#61) and the maxillary left lateral incisor (#62).
The patient’s medical history was unexceptional, and there was no family history of dental abnormalities and no parental consanguinity. No history of trauma was recorded.
The patient reported an occasional hypersensitivity to thermal stimulation (cold and heat) and to sweet in the two anterior carious teeth.
General and extraoral examinations appeared to be noncontributory.
The patient had complete primary dentition. Intraoral examination revealed the presence of a large upper left cen- tral incisor (#61) with slightly deep and decayed buccal and lingual grooves and the presence of extensive caries on the distal, lingual, and incisal surfaces of the left lateral incisor (#62) (Figures 1(a) and 1(b)).
Functional examination showed nasal breathing, infant swallowing, and functional chewing.
Figure 1: Intraoral photographs. Carious large crown of tooth 61 associated with dental caries of tooth 62 (a). Occlusal photograph showing the anterior teeth nonalignment and distal rotation of tooth 61 (b).
Figure 3: Panoramic radiograph showing the morphology of tooth 22 with a slight developmental delay and rotation.
Figure 2: Radiographic examination showing the morphology type: tooth 61 with a single root and a large central root canal. Periapical radiograph (a). Maxillary occlusal radiograph (b).
Periapical radiograph and maxillary occlusal radiograph exhibited the presence of a single large central root canal in the geminated tooth. The carious lesions in both teeth 61 and 62 were extensive and near the pulp chambers (Figures 2(a) and 2(b)).
Panoramic radiograph showed normally erupting per- manent incisors, except for the permanent upper left lat- eral incisor (#22) which exhibited a rotation and a slight developmental delay compared to its homologous tooth (#12) (Figure 3).
Diagnosis of gemination rather than fusion of the maxil- lary left central incisor (#61) was based on the presence of a complete dentition and on the radiography showing the pres- ence of one root canal for the tooth. Since the patient’s chief complaint was carious lesions of the anterior geminated tooth and its contiguous tooth, our decision was to ade- quately restore the aﬀected teeth.
A detailed explanation was given to the patient’s parents regarding the treatment approach. Written informed consent was obtained from the parents, both for the treatment proce- dure and for the publication of the case report.
Removal of caries was performed using a round carbide metal bur mounted on a low-speed contra-angle (Dentsplay Maillefer, Ballaigues, Switzerland) under local anesthesia and rubber dam isolation. As a pulp exposure occurred, the coro- nal pulp was tenderly excised with a round bur (Dentsplay Maillefer, Ballaigues, Switzerland) on a slow-speed handpiece (NSK Pana-Max, USA).
Hemostasis was achieved by the application of sterile cot- ton pellets for 3 minutes. Then, a cotton pellet was soaked in 2% glutaraldehyde solution, and it was applied in the pulp chamber for 10 minutes. The cotton pellet was later removed, and the pulp chamber was ﬁlled with a thick paste of zinc oxide eugenol (ZOE) (Element Zinc oxide eugenol tempo- raryﬁlling material, USA). One week later, the two teeth were
asymptomatic, and direct restoration of dental crowns with composite resin (3M ESPE® Restorative Universal Compos- ite A2 and B2) was performed (Figures 4(a) and 4(b)).
The patient was satisﬁed with the functional and esthetic rehabilitation of the anterior teeth.
A regular 3-month follow-up program was ensured to control the development of tooth 22 and to conﬁrm the pos- sibility of deformation or dysmorphia.
At the 9-month follow-up appointment, the tooth was esthetically stable with no pathological clinical signs. The follow-up periapical radiograph showed a perfectly sealed coronal restoration of teeth 61 and 62 (Figure 5).
2.2. Case Report 2. A six-year-old Tunisian girl was referred to the Pediatric and Preventive Dentistry Department at the Faculty of Dental Medicine of Monastir with a chief complaint of dental caries in the primary mandibular left canine (#73).
The patient’s medical history was unremarkable, and there was no family history of dental anomalies. No consan- guinity was reported, and the patient did not undergo any dental trauma.
General and extraoral examinations seemed noncontributory.
Intraoral examination revealed a mixed dentition with the absence of tooth 71 and the presence of dental caries on the gingival third of the labial surface of tooth 73.
The contiguous primary mandibular left lateral incisor (#72) had a large crown and deep grooves on the labial and lingual surfaces (Figure 6). Examination of occlusion exhib- ited an anterior open-bite related to the thumb sucking habit.
Functional examination revealed dysfunctional chewing, infant swallowing, and nasal breathing.
Anterior occlusal radiograph of the mandibular arch revealed a double tooth type IV morphology since separate
Figure 4: Treatment of teeth 61 and 62. Periapical radiograph showing pulpotomy (a). Coronal restoration (b).
pulp chambers and root canals with two distinct but joined roots were observed (Figure 7).
By calculating the number of teeth on the dental arch and the previous exfoliation of tooth 71, it was concluded that the malformation was the result of the fusion of tooth 72 with a supernumerary tooth #72’.
A detailed explanation was given to the patient’s parents who signed a written consent for the treatment process and the publication of the case report.
Caries excavation was performed on tooth 73 using a round carbide metal bur mounted on a low-speed contra- angle (Dentsplay Maillefer, Ballaigues, Switzerland) and rub- ber dam isolation under local anesthesia.
After the application of 2% chlorhexidine cavity disinfec- tant (Consepsis Ultradent, USA), restoration of tooth 73 using composite resin (3M ESPE® Restorative Universal Composite A2 and B2) was performed.
Preventive measures were applied for the asymptomatic noncarious fused tooth. They included the restoration of the deep grooves using ﬂowable composite (PRIME-Dent®
ﬂowable composite A2) (Figure 8). Follow-up visits were scheduled every 3 months.
A panoramic radiograph was performed after the clinical management of teeth #72 and #73. It showed the presence of all the mandibular permanent teeth without any abnormal signs (Figure 9).
The patient was satisﬁed with the restoration provided, and she was informed that tooth #72 with a large crown would soon exfoliate.
The patient was also given an interceptive treatment using a functional education device. Recommendations to stop the thumb sucking habit to manage the open-bite and to correct the dysfunctions were also provided.
At the 6-month follow-up visit, the fused tooth was still caries-free, and the two permanent mandibular central inci- sors erupted normally without any dental crowding issues (Figures 10(a)–10(c)).
Figure 8: Placement of sealants in the groove of the fused tooth 72 and restoration of the tooth 73.
Figure 9: Panoramic radiograph showing the absence of dental abnormalities in the permanent teeth.
Figure 5: Periapical radiograph of the geminated tooth 61 and its contiguous tooth 62 at the 9-month follow-up visit: the presence of sealed coronal restoration of the two primary teeth with no pathological signs.
Figure 6: Fusion of the clinical crown of tooth 72 with a supernumerary tooth 72’.
Figure 7: Anterior occlusal radiograph of the mandibular arch showing a type-4 morphology and an incomplete fusion of tooth 72 with a supernumerary tooth.
PDT represent 75% of primary teeth dental anomalies, with fusion accounting for 94% of cases and gemination account- ing for 6% of cases .
The diﬀerential diagnosis of fusion includes gemination and macrodontia .
Mader’s “two tooth” rule  can be a practical method for diﬀerentiating between fusion and gemination.
In fact, if the abnormal tooth is considered as“two teeth”
and the total number of teeth in the dental arch is normal, fusion is therefore determined. However, when the atypical tooth is considered as“two teeth” and the resulting number of teeth in the dental arch is higher than usual, then, the diag- nosis is either gemination or fusion between normal and supernumerary teeth.
Another diﬀerentiating point with regard to the two abnormalities is that the fusion between a regular and super- numerary tooth exhibits two distinct halves of the united crown whereas in the case of gemination the two halves of the united crown appear as mirror images . Macrodontia is deﬁned as an abnormal increase in the tooth size with a usual crown, root, and pulp anatomy. Unlike gemination, macrodontia does not present a biﬁd crown and deep grooves .
PDT with deep grooves are more susceptible to dental caries and periodontal problems compared to nonaﬀected teeth. Thoseﬁssures facilitate plaque accumulation and den- tal caries formation as they may be hard to brush . There- fore, according to the clinical situation, three treatment modalities are available, including preventive measures, a restorative approach, and a surgical procedure .
Intact and asymptomatic PDT commonly require a pre- ventive approach, involving localﬂuoride application, early placement ofﬁssure sealants in the deep grooves, and regular
3-month follow-up program. Dietary changes are also rec- ommended. When a primary double tooth presents a carious lesion, it should be restored with composite resin. In case of trauma or esthetic concerns as seen in maxillary anterior double teeth, guided composite resin restoration using putty silicone is recommended .
The third solution is the extraction of the abnormal tooth. This treatment modality can be considered when deep caries lesions, exacerbating tooth mobility or root resorption, are diagnosed. When extraction is performed, space mainte- nance should be provided when necessary . Regarding periodontal issues, strict oral hygiene is required.
The speciﬁcity of the current cases can be due to the mul- tiple eﬀects of PDT on the primary dentition and the reper- cussions on the permanent successors.
In fact, PDT may cause malocclusions like dental dia- stema if the fusion occurs between two normal teeth. They may also cause dental crowding if the fusion occurs between a normal tooth and a supernumerary tooth .
Reduction in the arch length, deviation of the midline, and esthetic problems due to the irregular morphology may also occur in PDT [9, 15].
Thus, restorative, periodontal, cosmetic, and orthodontic concerns may be necessary to manage the diﬀerent problems.
In theﬁrst case report, distal rotation of the geminated primary maxillary left central incisor (#61), nonalignment of the primary maxillary anterior teeth, and esthetic issues were noticed.
However, in the second case, the patient presented an anterior open-bite related to the thumb sucking habit, not to the fused mandibular tooth.
In the study of Aydinbelge et al. , dental abnormalities on the permanent successors were found in 69.4% of the chil- dren with PDT. Dental anomalies, such as aplasia, hypero- dontia, hypodontia, double tooth formation, peg-shaped
Figure 10: Intraoral photographs of the fused tooth 72 at the 6-month follow-up visit. Stable state with no pathological problems in the two teeth (72 and 73) (a). Occlusal view revealing the anterior teeth proper alignment (b). Photograph of occlusion showing the patient’s anterior open-bite (c).
in development. Moreover, the patient’s age should be taken into account.
In the second case report, the 6-month follow-up visit showed proper alignment of the anterior mandibular perma- nent teeth. However, interceptive treatment to manage the open-bite and oral dysfunctions was scheduled.
Follow-up visits every 3 months at the Pediatric and Pre- ventive Dentistry Department were scheduled to control the permanent teeth development.
Many factors impact the prognosis of PDT, involving the tooth condition and the associated complications, such as dental caries and malocclusions. When a primary double tooth does not have any indication to be extracted, prognosis is usually favorable .
In the two cases, preventive, restorative, and regular monitoring were chosen as the two double teeth were restorable.
Finally, to manage this developmental disorder success- fully requires an early diagnosis, a convenient choice of the treatment modality, and a regular 3-month follow-up pro- gram. It is also recommended to determine the presence of any dental anomaly in the permanent successors.
PDT are one of the most frequent dental anomalies in pri- mary dentition.
Clinical and radiographic examinations are required in the diagnosis of PDT, and a multidisciplinary treatment is necessary in some cases.
Conflicts of Interest
The authors declare that they have no conﬂicts of interest.
 M. O. Folayan, M. Alade, A. Adeniyi, M. El Tantawi, and T. L.
Finlayson,“Association between developmental dental anom- alies, early childhood caries and oral hygiene status of 3-5- year-old children in Ile-Ife, Nigeria,” BMC Oral Health, vol. 20, no. 1, 2020.
 P. F. Kramer, C. A. Feldens, S. H. Ferreira, M. H. Spiguel, and E. G. Feldens,“Dental anomalies and associated factors in 2- to 5-year-old Brazilian children,” International Journal of Paedi- atric Dentistry, vol. 18, no. 6, pp. 434–440, 2008.
 T. Yonezu, Y. Hayashi, J. Sasaki, and Y. Machida,“Prevalence of congenital dental anomalies of the deciduous dentition in Japanese children,” The Bulletin of Tokyo Dental College, vol. 38, no. 1, pp. 27–32, 1997.
 L. Aguiló, J. L. Gandia, R. Cibrian, and M. Catala,“Primary double teeth. A retrospective clinical study of their morpho-
pp. 50–52, 2011.
 H. Açıkel, S. İbiş, and E. Şen Tunç, “Primary fused teeth and ﬁndings in permanent dentition,” Medical Principles and Prac- tice, vol. 27, no. 2, pp. 129–132, 2018.
 R. Cheng, X. Chen, S. Liu, L. Pan, and X. Wu,“An epidemio- logical survey on fusion of deciduous teeth of 4286 kindergar- ten children in Shenyang city,” Shanghai Kou Qiang Yi Xue, vol. 12, no. 6, pp. 424–426, 2003.
 M. Aydinbelge, A. E. Sekerci, S. Caliskan, H. Gumus, Y. Sisman, and K. Cantekin,“Clinical and radiographic evalu- ation of double teeth in primary dentition and associated anomalies in the permanent successors,” Nigerian Journal of Clinical Practice, vol. 20, no. 7, pp. 847–851, 2016.
 L. M. Santos, F. D. S. Forte, and M. J. C. Rocha,“Pulp therapy in a maxillary fused primary central incisor - report of a case,”
International Journal of Paediatric Dentistry, vol. 13, no. 4, pp. 274–278, 2003.
 S. Bernardi, S. Bianchi, G. Bernardi et al.,“Clinical manage- ment of fusion in primary mandibular incisors: a systematic literature review,” Acta Odontologica Scandinavica, vol. 78, no. 6, pp. 417–424, 2020.
 D. B. Nandini, B. S. Deepak, M. Selvamani, and H. K. Puneeth,
“Diagnostic dilemma of a double tooth: a rare case report and review,” Journal of Clinical and Diagnostic Research, vol. 8, no. 1, pp. 271-272, 2014.
 C. L. Mader,“Fusion of teeth,” The Journal of the American Dental Association, vol. 98, no. 1, pp. 62–64, 1979.
 M. Milano, S. V. Seybold, G. McCandless, and R. Cammarata,
“Bilateral fusion of the mandibular primary incisors: report of case,” Journal of Dentistry for Children, vol. 66, no. 4, pp. 280–
 S. Lochib, K. R. Indushekar, B. G. Saraf, N. Sheoran, and D. Sardana,“Occlusal characteristics and prevalence of associ- ated dental anomalies in the primary dentition,” Journal of Epidemiology and Global Health, vol. 5, no. 2, pp. 151–157, 2015.
 A. Z. Zengin, P. Celenk, K. Gunduz, and M. Canger,“Primary double teeth and their eﬀect on permanent successors,” Euro- pean Journal of Paediatric Dentistry, vol. 15, no. 3, pp. 309– 312, 2014.