Computer-generated study of the correlation between tooth, face, arch forms, and palatal contour.
BACKGROUND
Several factors have been suggested as aids for artificial tooth selection. Numerous methods have been devised for the evaluation of reliable esthetic factors in determining artificial tooth form. There is no universally accepted single esthetic factor that can be used reliably to aid artificial tooth selection.


OBJECTIVE
This article describes a new method incorporating a computer program to analyze four esthetic factors: form of the face, arch form, palatal contour, tooth shape, and to determine whether there was correlation between tooth, face, and arch forms and palatal contour.


METHODS
Impressions were made of the maxillary dentition of 50 dentate undergraduate dental students with irreversible hydrocolloid impression material and casts formed. A standardized photographic procedure was used to record portrait slides of each subject's face and of maxillary dental arches and central incisors made from dental casts. A comprehensive computer program was developed to correlate esthetic factors by superimposition.


RESULTS
Superimposing outline form between face, tooth, and arch showed that for tooth to face form nearly half the comparisons were dissimilar and only 22% corresponded. This is the lowest level of correspondence in this group. Highest correspondence (28%) occurred between arch to face form, followed by arch to tooth form (24%). Arch to tooth showed the lowest level of dissimilarity (32%). For correlation among the four factors across the sample group based on a comparison of classifications in each subject, men tended to dominate tapering classes, whereas women dominated square and ovoid classes.


CONCLUSIONS
Correspondence of outline forms through superimposition revealed an insignificant correlation between face, tooth, and arch forms. Although this method applies high technology, it does not improve the accuracy of determining shape and size of teeth in an edentulous patient. The cost and complexity of the method of measurement may also make it impractical for common application.
Department of Oral and Dental Science, Bristol Dental School and Hospital, United Kingdom.
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Sellen
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Jagger
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Harrison
D000328:Adult; D000464:Alginates; D003658:Decision Making, Computer-Assisted; D003724:Dental Arch / Q000033:anatomy & histology*; D003760:Dental Impression Materials; D003761:Dental Impression Technique / Q000295:instrumentation; D017267:Dental Prosthesis Design; D004955:Esthetics, Dental; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007180:Incisor / Q000033:anatomy & histology; D007575:Jaw, Edentulous / Q000534:rehabilitation; D008297:Male; D008437:Maxilla; D003765:Models, Dental; D010159:Palate / Q000033:anatomy & histology*; D015203:Reproducibility of Results; D012984:Software; D014070:Tooth / Q000033:anatomy & histology*; D014093:Tooth, Artificial
D000464:Alginates; D003760:Dental Impression Materials