Bolton tooth size discrepancy in normal occlusion and in different types of malocclusions and its relationship to arch form and tooth positioning

Luiz Sérgio CARREIRO, Ary SANTOS-PINTO, Dirceu Barnabé RAVELI, Lídia Parsekian MARTINS

The general purpose of this study was to evaluate tooth size discrepancy in normal occlusion and in different malocclusion types and its relationship to measurements which determine arch form and anterior tooth positioning. One hundred and eighty ive sets of casts of leucoderms were divided into four groups: Group 1 (consisted of 41 pairs of models with Normal Occlusion, 20 males and 21 females); Group 2 (consisted of 44 pairs of models with Class I malocclusion, 22 males and 22 females); Group 3 (consisted of 54 pairs of models with Class II, div. 1, malocclusion, 28 males and 26 females) and Group 4 (consisted of 46 pairs of models with Class III malocclusion, 23 males and 23 females). No sexual dimorphism was observed between tooth size discrepancies and different types of dental occlusion; the proportions stated by Bolton were not applied to the Normal Occlusion group; in Normal Occlusion, Class I, Class II and Class III there was an overall ratio excess in the lower arch; in Class I there was an equal anterior excess distribution in upper and lower arches; in Normal Occlusion, Class II and Class III there was a prevalent incidence of anterior ratio excess in lower arch; upper arch excess did not contribute to malocclusion occurrence and overall and anterior discrepancies did not interfere with arch width and length, as well as with anterior tooth positioning.

Keywords: Tooth size discrepancy. Arch dimensions. Normal occlusion. Malocclusion. Incisor irregularity.

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