Fusing the Gap—Strategic Approaches in Managing Primary Double Teeth: A Report of Two Cases

Abstract

Aim and background

This case report highlights various management strategies for primary double teeth (PDT), focusing on the importance of early intervention and timely care to enhance oral health and overall quality of life in these children.

Case description

An incidental finding of PDT was noted in a 4-year-old boy, and preventive techniques were followed sequentially to interfere with caries initiation in a healthy PDT. In the second case, esthetic rehabilitation of a cariously involved, symptomatic PDT was carried out in a 4-year-old boy, emphasizing the importance and impact of timely intervention in such cases.

Conclusion

This case report not only presents a preventive and minimally invasive strategy to avoid caries initiation in PDT but also explores esthetic rehabilitation for caries-affected PDT, highlighting a comprehensive and innovative approach in managing this condition.

Clinical significance

Precise and early diagnosis of PDT directly influences the treatment outcomes. PDT often increases the risk of dental caries, potentially leading to premature tooth loss. Given its impact on the succedaneous dentition, timely intervention is crucial to prevent long-term complications.

How to cite this article

Sruthi PS, Seetha SM, Syriac G, et al. Fusing the Gap—Strategic Approaches in Managing Primary Double Teeth: A Report of Two Cases. Int J Clin Pediatr Dent 2026;19(2):244–249.

Introduction

Odontogenesis is a coordinated, sequential process characterized by a complex chain of steps ultimately resulting in the formation of a tooth and its surrounding structures. Several progressive stages, such as tooth initiation, proliferation, histodifferentiation, morphodifferentiation, apposition, and bone remodeling, take place during tooth formation and eruption.¹ Tooth development is a continuous process that unfolds from embryonic stages to early adulthood, and any disruptions during this intricate journey can lead to developmental tooth anomalies. Developmental anomalies in deciduous dentition refer to irregular number, size, shape, and structure of deciduous teeth, which can negatively impact oral health and function. Recognizing developmental dental anomalies is crucial, as they can lead to malocclusion, increased caries susceptibility, esthetic concerns, and other functional problems, emphasizing the timely need for intervention.²

Prevalence of anomalies in deciduous dentition ranges from 0.4 to 8.1%,^3,5 with fusion and gemination having a prevalence of 0.1–5⁶ and 0.1−1%,⁷ respectively. Fusion or synodontia occurs when two or more distinct tooth germs merge, resulting in a joined structure involving the enamel or both enamel and dentin. In gemination, a single tooth bud tries to split, resulting in an irregular tooth shape or structure.⁸ When faced with diagnostic uncertainty between fusion and gemination, the term primary double teeth (PDT) can be employed as a collective descriptor.⁹ According to a study by Santanu et al.,² the majority (81.8%) of cases showed unilateral distribution, of which 91.9% were found in the mandibular arch. A bilateral distribution was observed only in 18.2% of cases, typically affecting the mandibular lateral incisors and canines. Thus, the existing literature suggests that the prevalent developmental anomaly in the deciduous teeth is PDT, of which fusion is the most frequent manifestation.^5,10,11 Gemination is commonly seen in the maxilla, while fusion is common in the mandible.¹² PDT are usually found in the mandibular anterior region involving the lateral incisors and canines.¹³ There are equal chances for these developmental anomalies to occur in both genders.¹²

Primary double teeth poses significant clinical challenges, necessitating a comprehensive treatment approach that prioritizes functional and esthetic issues. It is the clinician's paramount responsibility to restore a child's smile with the same diligence as they would for an adult. This case report, according to the CARE guidelines,¹⁴ aims to highlight a proactive treatment strategy for managing primary tooth fusion.

Case Description

Case 1

Case Description and Management

A 4-year-old male child came to our outpatient wing with a chief complaint of pain and sensitivity in relation to the upper front teeth for 3 weeks. Intraoral examination revealed hypoplastic upper anterior teeth with posteruptive breakdown of the incisors. Further examination revealed an incidental finding of PDT affecting the right mandibular lateral incisor and canine. Clinically, the double tooth appeared normal, with plaque accumulation along the line of partition separating the two joined teeth.

It was decided to address the chief complaint first, and after the radiographic assessment of the upper incisors, acidulated phosphate fluoride (APF) application (Prevest DenPro Limited, India) was done using foam trays covering all the erupted deciduous teeth in his oral cavity. Subsequent visits involved:

• Pulpectomy for both upper central incisors: 51, 61.

• Silver diamine fluoride (SDF) application (Kedo Dental, India), followed by potassium iodide (KI), for both upper lateral incisors: 52, 62.

• Esthetic rehabilitation of the upper anterior teeth using Bioflx crowns (Figs 1A and B) (Kids-e-Dental LLP, Mumbai).

Figs 1A and B:

(A) Preop; and (B) Postop after Bioflx crown cementation

An intraoral periapical (IOPA) radiograph of the mandibular region confirmed fusion in the right lower anterior region, revealing a type IV PDT according to the classification by Aguiló et al.11 (Fig 2B). After cleaning and pumice polishing, pit and fissure sealant (3M ESPE, Minnesota, United States) was applied to the interdental groove of the fused teeth (Figs 2A and C). This proactive measure aimed to prevent the onset of dental caries and other potential complications.

Figs 2A to C:

(A) Before sealant placement; (B) IOPA of the PDT; and (C) After sealant placement

The parents were informed about the condition and the importance of maintaining oral hygiene in preventing further problems. Additionally, the importance of a well-balanced diet and its positive impact on their child's oral health were also emphasized. The timeline of events involved in the management of case 1 is depicted in Figure 3.

Fig 3:

Timeline of events involved in the treatment of case 1

Case 2

Case Description and Management

A male child of 4 years reported with a chief complaint of nocturnal pain involving the right lower front teeth region. On clinical examination, deep caries with pulp exposure in the fused right mandibular lateral incisor and canine was noted. There was no history of swelling or pus discharge. No relevant medical conditions or relevant family history were reported by the parent. The child's concern about the appearance of the decayed lower front tooth was apparent during interactions, as he was hesitant to smile. Radiographic examination revealed type III PDT according to Aguiló et al.¹¹ with coronal radiolucency approximating the pulp chamber. The planned treatment for the child included:

• Single-visit pulpectomy in the fused right lower lateral incisor and canine: 82, 83.

• Esthetic coronal rehabilitation.

Under rubber dam isolation and adequate local anesthesia, access cavity preparation was done with a sterile round bur (Garvansh Life Science (OPC) Private Limited, Madhya Pradesh). After pulp extirpation, initial canal patency was assessed with a #10 K file (MANI, INC., Japan), and working length determination was performed. The canals were chemomechanically prepared using the Kids E Rotary file system, #40−4% (Kids-e-dental LLP, Mumbai). Irrigation was done with sodium hypochlorite solution alternating with normal saline. One part of 5.25% sodium hypochlorite solution was taken and mixed with 1.1 parts of distilled water to get a concentration of about 2.5%. The canals were dried and obturated with calcium hydroxide [Ca(OH)₂] paste with iodoform (Figs 4A and B) (Meta Biomed, South Korea). An impression of the mandibular arch was taken using alginate after placing a type II GIC restoration on the fused 82 and 83 (Fig. 4C) (3M ESPE, Minnesota, United States) during the same visit. A wax mock-up was done on the cast in the lab to mimic the appearance of two separate teeth in place of the single fused tooth. Subsequently, a putty impression was taken using condensation silicone material (Orikam Healthcare India Pvt. Ltd., Mumbai) (Figs 4D and E). During the next visit, coronal rehabilitation was done esthetically by advocating the guided composite resin restoration technique using putty silicone. Composite shade A2 was used (3M ESPE, Minnesota, United States) (Figs 4F and G). The patient had follow-ups at monthly intervals for the first two visits, followed by scheduled reviews every 6 months. The timeline of events involved in management of case 2 is depicted in Figure 5.

Figs 4A to G:

(A) Preop IOPA; (B) Postop IOPA; (C) Lower alginate impression; (D) Wax mock-up done on cast; (E) Putty impression taken from both buccal and lingual aspect; and (F and G) Pre- and postop after guided composite resin restoration respectively

Fig. 5:

Timeline of events involved in the treatment of case 2

Discussion

Developmental dental anomalies in primary teeth are predominantly represented by PDT (75%), which includes fusion (94% of cases) and gemination (6% of cases).¹³

Aguiló et al. in 1999 classified primary fused teeth into the following types¹¹ (Fig. 6):

Figs 6 A to D:

Diagrammatic representation of PDT types¹³

• Bifid crown with one root.

• Single large crown and root.

• Two fused crowns with double conical root.

• Two fused crowns and two fused roots.

According to Açıkel et al.,¹⁵ the most commonly occurring primary fused teeth was the third type, with two fused crowns with double conical root, while the least commonly occurring type was the second type, with single large crown and root. Zengin et al. reported the fourth type, with two fused crowns and two fused roots, as the most common type of fusion.¹⁶ These findings may be attributed to age-related resorption of the roots of primary teeth or issues with radiographic imaging, such as superposition, which can affect accurate assessment.¹⁵ The distribution of fusion also showed a jaw-specific pattern, with type I exclusively seen in the maxilla and type IV also commonly associated with the maxillary region, whereas the other two types, types II and III, were limited only to the mandible.¹¹

Double teeth are thought to result from a combination of factors, such as evolutionary changes, trauma, hereditary tendencies, and environmental influences. Research indicates a strong genetic influence of this condition.^17–20 Brook and Winter⁹ suggested that if PDT exhibits a genetic predisposition, it likely follows an autosomal dominant or autosomal recessive inheritance pattern with very little penetrance, lacking a clear Mendelian inheritance pattern.¹⁹ This dental anomaly can also be associated with various syndromic conditions, including chondroectodermal dysplasia, focal dermal hypoplasia, achondrodysplasia, median cleft facial syndrome, oral-facial-digital syndrome, otodental dysplasia, and Russell-Silver syndrome.²¹ Molecular pathways [hedgehog, wingless-related integration site (Wnt), muscle segment homeobox (MSX), tumor necrosis factor (TNF), bone morphogenetic protein (BMP), fibroblast growth factor (FGF)] govern tooth development. Disruption of these pathways can cause dental anomalies, including gemination, fusion, and extra teeth.²² During tooth development, disturbance during the morphodifferentiation stage plays a crucial role in PDT.²³ The proximity of the adjacent tooth germs can result in the breakdown of the intervening tissue, resulting in their union and subsequent formation of PDT, but Ooe et al.²⁴ observed that double teeth can form even if sufficient space exists between the developing tooth germs. Moreover, the dental follicle surrounding the tooth germ will prevent the adjacent developing teeth from getting fused.¹⁹ Hunasgi et al.²² suggest that exposure to ionizing radiation may contribute to PDT, highlighting the influence of potential environmental factors.

The association with permanent teeth malformation is also not uncommon in a child with PDT. Given the proximity of PDT to their permanent successors, diagnostic accuracy is highly dependent on radiographic evaluation.¹⁹ The prevalence of anomalies in permanent dentition, including hypodontia, double teeth, and peg-shaped teeth, was 72.7%.¹³ PDT can lead to delayed root resorption due to the larger root mass, potentially causing delayed or ectopic eruption of the permanent successors.^7,25 Thus, PDT may compromise alignment of succedaneous dentition, potentially impacting the occlusion and esthetics. The presence of deep grooves increases the risk of decay and problems related to the periodontium due to the accumulation of plaque.¹³

Timely identification allows for preventive measures to be taken, reducing the risk of malocclusion in permanent dentition and promoting healthy deciduous retention until its natural exfoliation.²¹

The three lines of treatment strategies include:

• Preventive approach (observation, monitoring, fluoride application, and sealant placement).

• Restorative approach with or without pulp therapy.

• Surgical approach (removal of the affected tooth or teeth).

These approaches aim to address esthetic, functional, and developmental concerns. The key factors in choosing a treatment for double teeth include tooth mobility, root type, and root canal morphology.²¹

Prevention can be more effective and less complicated than invasive treatment, especially in children. Early preventive strategies that can be provided include topical fluoride and pit-and-fissure sealant application. Also, diet counseling along with stringent oral hygiene instructions should be emphasized. As a result, parents can help their children develop strong oral health foundations. In our first case, PDT was an incidental finding in the lower anterior region without any associated pathology and, hence, was opted for its preventive management.

In cases of deep caries with pulpal involvement, as in our second case, pulp therapy would be necessary. Satisfactory results using the guided composite restoration technique²¹ with putty silicone effectively addressed the child's esthetic concerns.

In deep caries with pathological tooth mobility and root resorption, extraction might be the most suitable treatment option to prevent further complications. Premature extraction should be followed by space maintenance.²¹

Conclusion

Pediatric oral health has a major role in overall child development and well-being. The scarcity of case series on managing PDT highlights the value of documentation to enhance understanding and refine treatment strategies for this dental anomaly. Comprehensive management, including early diagnosis, a proper treatment plan, and regular checkups for the management of PDT, should be followed to avoid any potential complications and to ensure optimal outcomes.

Orcid

Sruthi Priyadharshiny S https://orcid.org/0009-0001-0014-1722

Suchithra Muraleedhar Seetha https://orcid.org/0000-0002-4560-9130