Unusual Natal Tooth.

Sir,

A 1-day-old female received consultation from an oral and maxillofacial surgeon. A 3 × 4-mm hard, yellowish mass with approximately 1 mm of translucent and whitish pedunculated soft tissue connected to her mandibular alveolar ridge was observed in the left lower primary central incisor region (Fig. 1). The baby was born by normal delivery at 39 weeks’ gestation; her birth weight was 3,424 g. She had no congenital malformations and no neurological, cardiologic, or abdominal problems. The mother of the baby was a 34-year-old Japanese woman; she was on no medications, did not use alcohol or tobacco during the pregnancy, and had no medical history. She had no experience with chemical exposure. The father of the baby was a 30-year-old Japanese man with asthma. The family had no history of such lesions. The baby had a 2-year-old sister who had no such lesions and no medical history. A clinical diagnosis of suspected natal tooth was made, and the patient was scheduled for surgical excision after pediatric evaluation on the next day. However, the next day, the hard mass had disappeared from her mouth and was subsequently found in her faeces. The hard mass was picked up and washed by midwives and was placed in 10% formalin solution. The hard mass was a yellowish incisor crown-like structure without a root. The soft tissue had disappeared. Hematoxylin–eosin staining of the decalcified hard mass revealed that it had a structure of thin dentin and large pulp space (Fig. 2).

Fig. 1.

Intraoral photograph from the 1-day-old baby. A 3 × 4-mm hard, yellowish mass with approximately 1 mm of pedunculated soft tissue was connected to the mandibular alveolar ridge in the left lower central primary incisor region.

Fig. 2.

Hematoxylin–eosin staining of decalcified hard mass. A structure of thin dentin and large pulp space were observed at a magnification of × 2.

However, there was no pulpal tissue. The pulpal tissue might have been removed during washing. The final diagnosis was natal tooth with unknown soft tissue. In such cases, natal teeth might fall out due to premature eruption in the foetal stage. Interestingly, the natal teeth might be connected to the alveolar ridge by pedunculated soft tissue with or without nerves or vascularity in the foetal stage. No eruption of the left lower primary central incisor was found in 11-months follow-up. The natal tooth might be the early eruption of left lower primary central incisor. To the best of our knowledge, this is the first report of an unusual natal tooth in a newborn. A review of the literature reported that the incidence of natal teeth is approximately 1:2,000 to 1:3,000 live births. The most commonly affected teeth are the lower primary central incisors. The majority of natal teeth present as early eruption of normal primary deciduous dentition; less than 10% of natal teeth are supernumerary.

Natal teeth may resemble normal primary dentition in size and shape; however, the teeth are often smaller, conical, and yellowish and have hypoplastic enamel and dentin with poor or absent root formation.[1] Although no studies have confirmed the mechanism for natal and neonatal tooth generation, the superficial position of the germ associated with a hereditary factor seems to be the most accepted possibility.[2] This report might contribute to the elucidation of the mechanism of natal and neonatal tooth generation.

ACKNOWLEDGEMENTS

The authors thank Ms. Fujima, Ms. Hasegawa, and Ms. Shirakawa for finding the missing natal tooth in baby feces, and Dr. Hisami Matsumine for her valuable comments.