Relationship between the face and the tooth form.

The aim of this study was to re-examine Leon Williams geometric theory and to find the degree of correspondence between the face and the tooth form in the population of Zenica, Bosnia and Herzegovina. Two thousand individuals with intact frontal teeth, in age between 17 and 24 years, were measured for 3 horizontal distances on the face: temporal width (Ft-Ft), zygomatic width (Zyg-Zyg) and gonial width (Go-Go) and for 3 horizontal distances on the both upper incisors: cervical width (CW), contact point width (CPW) and incisal width (IW). The length of the face (Tr-Gn) as well as the length of the central maxillary incisors were also measured. The results revealed: 1. Men had significantly larger dimensions for all facial and tooth dimensions (p < 0.05) than women, except for the cervical tooth width (p > 0.05); the left and the right central incisors were of identical dimensions and forms (p > 0.05). 2. The width of upper central incisors were smaller approximately 1.5 mm than in west Europeans. 3. Upon the relation between the 3 horizontal dimensions measured on the face and upper maxillary incisor, 11 facial forms and 10 upper central tooth forms could be recognised in the study population, but 98% of the population had only 3 tooth and face forms. Face shapes: oval face--83.3%, square-tapered face--9.2% and tapered face--7%; tooth forms: tapered-square incisor--53%, oval incisor--30%, tapered incisor--16%. 4. Reversed and enlarged tooth form was in line associated with the facial form in only 30%, while the most common combination was of the oval face form and the tapered-square central incisor (45%). 5. These results disapprove William's theory and may be helpful for the choice of artificial teeth in complete denture construction and the dental industry.