Dentofacial Morphology in Third Molar Agenesis

Abstract

Objective: In the literature, some studies show a relation between tooth agenesis and craniofacial morphology, whereas otherauthors conclude that dental agenesis exerts little influence on dent facial structures. The objective of this study was to determinethe existence of any relation between bilateral agenesis of the maxillary and/or mandibular third molars and the anteroposteriordimensions and vertical growth pattern of the jaws.Subjects and Methods: Sixty-eight subjects between the ages of 13 and 17 years with bilateral agenesis of maxillary thirdmolars (group I, n=37), bilateral agenesis of the mandibular third molars (group II, n=19), and agenesis of all third molars (groupIII, n=12) as well as 33 subjects without third molar agenesis (group IV) were selected from the radiology archive. A before andafter treatment orthopantomograph and the pretreatment cephalometric radiograph of the subjects were used. Several angularand linear parameters representing the anteroposterior dimensions and vertical growth pattern of the jaws were measured oncephalometric radiographs. The data were analyzed by Kolmogorov-Smirnov test, analysis of variance for 1 factor, andindependent-samples t test. Statistical significance was set at p,0.05.Results: When the agenesis groups (groups I, II, and III) were compared with the control group, it was found that all parametersrepresenting the anteroposterior dimensions of both jaws (A-Ptm, CoA, ANS-PNS, CoB, CoGn, CoPog, and ABRB) weresignificantly smaller in all agenesis groups (p,0.05). The parameters reflecting the vertical growth pattern did not represent anydifference among the groups (p.0.05).Conclusion: In subjects with bilateral or total third molar agenesis, the anteroposterior dimensions of both jaws were smaller incomparison with subjects without tooth agenesis. Vertical growth pattern of the jaws did not differ among the groups. (Turkish JOrthod 2015;28:7–12)