The aim of this study was to investigate the bone area in the posterior region, which is important for mandibular molar distalization in skeletal Class I and Class III individuals with normodivergent and hyperdivergent vertical growth patterns. Materials and MethodsIn this study, cone-beam computed tomography scans of 120 individuals divided into 4 groups as Class I normodivergent (Group-I), Class I hyperdivergent (Group-II), Class III normodivergent (Group-III) and Class III hyperdivergent (Group-IV). Retromolar space at crown level measurements were performed on CBCTderived panoramic radiographs and axial sections. Retromolar space at the root level was measured 2mm, 4mm, 6mm, 8mm and 10mm apical to cemento-enamel junction at CBCT axial sections. ResultsRetromolar space decreased towards the root apex in all groups and smallest retromolar space was level of CEJ 10mm in all groups. At any root level, the distal root of the mandibular second molar tooth was in contact with the mandibular inner or outer lingual cortex; 50% in Group-I, 46.7% in Group-II, 7% in Group-III and 7% in Group-IV. ConclusionsIn normodivergent individuals, the retromolar area length at the root level is observed to be higher in Class III than in Class I at almost every level. In hyperdivergent individuals, on the other hand, only at CEJ 10 level, it is higher in length in Class III than in Class I. Vertical growth pattern has no effect on the root and crown level retromolar space in Class I and Class III individuals. Clinical RelevanceCBCT provides more useful information than panoramic radiographs for patients who are scheduled for large mandibular molar distalization

Objectives The aim of this study was to investigate the bone area in the posterior region, which is important for mandibular molar distalization in skeletal Class I and Class III individuals with normodivergent and hyperdivergent vertical growth patterns. Materials and Methods In this study, cone-beam computed tomography scans of 120 individuals divided into 4 groups as Class I normodivergent (Group-I), Class I hyperdivergent (Group-II), Class III normodivergent (Group-III) and Class III hyperdivergent (Group-IV). Retromolar space at crown level measurements were performed on CBCT-derived panoramic radiographs and axial sections. Retromolar space at the root level was measured 2mm, 4mm, 6mm, 8mm and 10mm apical to cemento-enamel junction at CBCT axial sections. Results Retromolar space decreased towards the root apex in all groups and smallest retromolar space was level of CEJ10mm in all groups. At any root level, the distal root of the mandibular second molar tooth was in contact with the mandibular inner or outer lingual cortex; 50% in Group-I, 46.7% in Group-II, 7% in Group-III and 7% in Group-IV. Conclusions In normodivergent individuals, the retromolar area length at the root level is observed to be higher in Class III than in Class I at almost every level. In hyperdivergent individuals, on the other hand, only at CEJ10 level, it is higher in length in Class III than in Class I. Vertical growth pattern has no effect on the root and crown level retromolar space in Class I and Class III individuals. Clinical Relevance CBCT provides more useful information than panoramic radiographs for patients who are scheduled for large mandibular molar distalization