Bilateral Symmetrical Fusion of Permanent Mandibular Lateral Incisors and Canines: A Rare Clinical Case.

Fusion is a rare developmental anomaly characterized by the union of two adjacent tooth germs during the morphodifferentiation stage of tooth formation, resulting in a single enlarged tooth. Its prevalence ranges from 0.4% to 0.9% in the primary dentition and approximately 0.2% in the permanent dentition. Unilateral fusion is more commonly observed in the primary dentition compared to the permanent dentition. Bilateral fusion in permanent teeth is extremely rare, with a reported prevalence of only 0.05%, most frequently affecting the incisors. Bilateral fusion involving the mandibular permanent lateral incisors and canines is even more uncommon. Due to its low prevalence in the permanent dentition, the clinical significance, diagnosis, and radiographic presentation of such anomalies are poorly understood. This paper highlights an exceptionally rare case of bilateral symmetrical fusion of the permanent mandibular lateral incisors and canines, which led to dental crowding and challenges in maintaining effective plaque control. To the best of our knowledge, this specific type of bilateral fusion has not been previously reported in the literature.