Journal of Dentistry, 1, 263-264

Six supernumerary mandibular premolars Yehoshua Shapira, D.M.D. Jerusalem, Israel

ABSTRACT A symmetrical occurrence of 6 fully formed supernumerary premolar teeth in the mandibular arch, 3 on either side, in a 29-year-old male is reported.

INTRODUCTION STUDIES on supernumerary teeth have shown that they appear more frequently in the maxilla than in the mandible, and most commonly in the premaxillary region (Stafne, 1932; Macphee 1935). However, supernumerary premolars have been reported to occur more frequently in the lower jaw (Stafne, 1932; Price and Hoggins, 1969; Bowden, 1971). A greater

incidence of supernumerary premolars has been found in males and their location has been usually reported to be lingual or below the normal premolars (Price and Hoggins, 1969; Bowden, 1971).

Although supernumerary teeth in theperman- ent dentition occur frequently the symmetrical occurrence of 6 or more supernumerary premolars in the lower jaw is rare.

CASE REPORT The patient, a male aged 29 years, was referred by his dental practitioner after the eruption of 2 supernumerary premolars following the extraction of the mandibular left first molar. On clinical examination it was found that apart from the mandibular left first molar and right second molar

Fig. I.-Radiographs of the mandible, showing 3 supernumerary premolars in the left (A) and right (B) premolar regions.

264 Journal of Dentistry, Vol. 1 /No. 6

which had been extracted, all the permanent teeth had erupted.

A full dental radiographic examination revealed the presence of symmetrically distributed 6 super- numerary premolar teeth in the lower jaw, 3 on each side. Their crowns were normal in shape and size and resembled normal premolars. All the supernumerary premolars had fully formed roots and they were vertical and in a lingual relationship to the erupted premolars (Fig. I).

DISCUSSION Several theories, such as dichotomy, atavism, additional generation of tooth germ, have been suggested to explain the aetiology of super- numerary teeth (Gardiner, 1961). It has been stated that supernumerary teeth start their development at a later time than normal teeth (Stafne, 1932). Supernumerary premolar teeth at different stages of development were reported by Poyton, Morgan, and Crouch (1960).

The case reported here of 6 fully developed supernumerary premolars in an adult patient supports the findings of Price and Hoggins (1969) that supernumerary premolars with completed roots appear in patients aged 19 years or over, while in younger patients the roots are incompletely formed. Supernumerary premolars were therefore considered to belong to a second generation of premolars. The symmetrical appearance of 6 supernumerary premolars in the lower jaw may possibly be more than coincidental.

REFERENCES BOWDEN, D. E. J. (1971), Br. dent.J., 131,113. GARDINER, J. H. (1961), Dent. Pructnr dent. Rec.,

12,63. MACPHEE, G. C. (1935), Br. dent. J., 18,59. POYTON, G. H., MORGAN, G. A., and CROUCH, S. A.

(1960), OraZSurg., 13,964. PRICE, C., and HOGGINS, G. S. (1969), Br. dent. J.,

126,224. STAFNE, E. C. (1932), Dent. Cosmos, 74,653.