Osmana Omnia Tagelsir Sharif1, Shetty Raghavendra M2, Waliaa Tarun3

 1Dept. of Clinical Sciences, College of Dentistry, Ajman University, UAE.

2Center of Medical and Bio-allied Health Sciences Research, Ajman University, UAE.

3Dept. of Pediatric and Preventive Dentistry, Sharad Pawar Dental College and Hospital, Datta

Meghe Institute of Higher Education and Research (Deemed-to-be-University), Sawangi,

Maharastra, India.

Running title – Fusion in primary dentition

 Received: 09-03 -2023

Revised: 14-03-2023

Accepted: 20-03-2023

Address for correspondence: Omnia Tagelsir Sharif Osmana, MSc (Pediatric Dentistry), Former Postgraduate Student, College of Dentistry, Ajman University, UAE

Email – omnia.taj92@hotmail.com

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 How to cite this article: Osmana O T S, Shetty R M, Waliaa T. Fusion of primary lateral incisor and canine with agenesis of the permanent lateral incisor: A case report. J Oral Biomed Sci 2023; 2: 40-43


 Developmental dental anomalies can be seen in teeth number, shape, size, position, and structure (1). The frequency of dental hard tissue developmental anomalies has been reported only in a few studies. Their prevalence has been reported in the literature as a range of 0.5% to 7% (2). Fusion and gemination are often called primary double teeth (PDT). PDT are the most common developmental dental anomalies in primary teeth (3-5).

Fusion is known as the union of two separated tooth germs (6). It is also known as conjoined teeth, twinned teeth or double teeth. The involved teeth appearance clinically can be normal- sized or large, depending upon the embryological union stage that occurs during the development. Fusion is usually confused with gemination especially if the supernumerary tooth is involved (2). Fusion is more commonly seen in primary dentition than in permanent dentition (7). In the primary dentition, the prevalence of unilateral fused teeth is 0.1% to 1.5% (2). However, Reddy and Munshi reported a prevalence of 0.14% in the Indian population (8). When there is a high incidence, genetics has an important role (9). Fusion can result in clinical complications related to spacing, appearance, and periodontal conditions (10). The agenesis of permanent teeth prevalence depends on the fused primary teeth combination (11).

Case report:

A six-year-old female reported to the Department of Pediatric Dentistry at Ajman University with the chief complaint of multiple carious teeth. The patient had no relevant medical history. The family history did not show any dental abnormalities. No history of dental trauma as stated by the child’s parents.

Intraoral examination showed a primary dentition with carious maxillary incisors, canines, and molars. Maxillary right permanent molars were partially erupted. Also, a dental fistula was noticed on the maxillary left canine and the first primary molar. The mandibular arch showed defective restorations and carious involvement on molars (Figure 1 & 2). The mandibular right primary lateral incisor and canine were present with an enlarged bifid crown (82 and 83). An incisal ditch was noticed between 82 and 83 (Figure 3).

Figure 1 & 2: Multiple decayed teeth in upper and lower arch

Figure 3: Fused primary mandibular lateral incisor and canine

The intraoral periapical radiograph showed that the enlarged bifid crown of the 82 and 83 teeth is due to fusion. The affected tooth revealed crowns and root fusion resulting in a pulp canal joining through pulp chambers. Missing tooth bud of 42 is also noticed (Figure 4).

Figure 4: Intraoral periapical radiograph

Treatment plan was developed after clinical and radiographical examination. Application of preventive measure was performed provided that the fused teeth are caries free. Topical fluoride application on the deep groove. Dietary changes and periodic follow ups were advised to the parents. Parents were informed about the missing permanent lateral incisor tooth bud. Follow-up appointments were ensured on 3,6, and 12 months (Figures 5 & 6). No carious involvement was seen on the fused teeth.

Figure 5: Clinical photograph at 3 months follow-up appointment

Figure 6: Clinical photograph at 6 months follow-up appointment


 A double tooth is a dental anomaly resulting from the fusion of two adjacent tooth germs. This usually occurs during the embryological period (6). Fusion can either be complete or incomplete according to the teeth developmental stage at the union time. When the fusion is complete, the crown usually appears large clinically with no substantial grove. In this situation, the pulp chamber appears as the common teeth. In case of incomplete fusion, usually, the crown shows a separating groove on the vestibular surface (12). The pulp chamber appears bifid or separated in case of an incomplete fusion as seen in the present study (6). Although the etiology of the fused or double teeth is still not fully understood,

different genetic and physical forces such as trauma have an important role in the fusion of tooth germs (13). It can also result as a secondary appearance of different syndromic disorders like Chondroectodermal dysplasia, achondrodysplasia, focal dermal hypoplasia, Russel-Silver syndrome, and otodental dysplasia (14). This type of dental anomaly can occur on both primary and permanent teeth. However, the incidence has been noted to be more in anterior primary teeth especially in the mandibular primary incisors either unilaterally or bilaterally (15,16). In the present case the fused primary mandibular lateral incisor and canine i.e, 82,83 succeeded by normally developing mandibular permanent canine but congenital absence of mandibular permanent lateral incisor. The findings of the present case are similar to the findings of Yuen et al that stated if fusion is present in primary dentition some of the primary incisor’s absence can be seen (17).

Fusion can cause some dental complications such as delay in the exfoliation, caries, subsequent permanent teeth impaction, supernumerary teeth presence, tooth misalignment with the possibility of a future malocclusion, and aplasia of the subsequent permanent teeth (16). Management of double teeth in child patients is usually planned according to a lot of factors such as combinations of fused primary teeth, fusion level and patient cooperation. The tooth mobility degree must be considered. When the successor permanent tooth will substitute the primary tooth shortly, no additional measures must be taken (18). A preventive approach should also be applied in the case of caries-free fused teeth by topical fluoride application, dietary changes, and periodic follow-ups (19). If caries is present, a restorative procedure should be done while endodontic treatment is needed in case of pulpal involvement (20). If extraction of the fused primary teeth was decided due to deep caries, confirmation of the permanent tooth bud’s presence is very important. In addition, orthodontics and prosthodontics management might be required to improve occlusion esthetically and functionally (21). Regular and long-term follow-up appointments are needed in the management of fusion (21).


Fused teeth are usually noticed during the routine oral examination. A careful clinical and radiographic assessment is important to confirm its presence in the primary dentition as fusion in primary teeth can be associated with anomalies in permanent dentition. Therefore, it is necessary to acknowledge this dental anomaly sooner and establish a suitable treatment plan.

Conflict of interest: None

 Source of support: Nil


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