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Linear variables and the presence of third molar in class III and class II/2 patients

BACKGROUND: Third molars differ from other molars in several respects. They are more variable in size, shape, timing of formation and eruption, and agenesis. Skeletal Class II patients generally have a large maxilla and/or small mandible, whereas skeletal Class III patients generally have a small maxilla and/or large mandible. Is there any connection between this statments and the timing of formating and eruption of third molars in respectivelly jaws? AIM: To determine the presence of third molar germs in patients with Class II/2 and Class III malocclusions regarding linear craniofacial characteristics. SUBJECTS AND METHODS: One hundred and fourtysix children. Examines with Class II/2 malocclusions amounted to 77 and those with Class III 69. Assessments were made from panoramic radiographs and lateral cephalograms. Two types of measurement of the linear cephalometric variables were undertaken, on lateral cephalograms: (1) Length of the maxilla (CoA) and (2) Length of the mandible (CoGn). Nonlinear regression equation and the Pearsonχ² was used to determine statistical significance in differences. RESULTS: Assessments showed that third molar germs were present significantly more often in the upper jaw in Class II/2 (58% vs. 44%) and in the lower jaw in Class III (83% vs. 69%). The correlation between the presence of upper third molar germs was found for values of CoA and correlation between the presence of lower third molar germs for values of CoGn. DISCUSSION: Presence and calcification of third molar crypt begins later in patient with Class II/2 malocclusion, that would be connected with earlier presence of space in jaws for crypt formating in subjects with Class III. Retromolar space and direction of face growth not affects vertical and sagittal changing of position of once formated crypt. CONCLUSIONS: The study confirmed correlation between the presence of third molar germs and sagital maxillomandibular relationship and length of the jaw and encourages investigation of the differences in calcifications of all permanent teeth in such malocclusions.

Class III; Class II/2; third molars

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