Compensatory characteristics of the maxillary first molars and central incisors: a retrospective study of 1738 cases

Objectives This study was designed to explore the compensatory characteristics of the maxillary first molars and central incisors at different age ranges for different skeletal discrepancies. Materials and Methods Lateral cephalograms of 1738 malocclusion cases taken before treatment were measured. It was categorized into adolescent and adult groups and then subcategorized into sagittal class I, II, and III and vertical hypodivergent, normodivergent, and hyperdivergent. The effects of different skeletal discrepancies on the inclination degree and dentoalveolar height of the maxillary first molars and central incisors were analysed. The differences in compensation between the two age groups were also compared. Results The maxillary first molar compensated significantly for both sagittal and vertical skeletal discrepancies ( P  < 0.01). The influence on the mesial inclination of the maxillary first molar followed the order: age > ANB > MP/SN. Adolescent maxillary central incisors did not show significant compensation for sagittal skeletal discrepancies in inclination degree ( F  = 0.990, P  = 0.372) and dentoalveolar height ( F  = 0.777, P  = 0.460). Moreover, the downward slope from the posterior to anterior of the adult maxillary occlusal plane relative to the palatal plane was flatter than that of adolescents. Conclusions Age exerting a stronger effect on the mesial inclination of the maxillary first molar than skeletal type.The degree of compensation differs between the maxillary central incisors and the maxillary first molars. Differences in compensation were also observed between adolescents and adults. Clinical Relevance Accurate understanding of differences in dentoalveolar compensation between anterior and posterior teeth across various skeletal patterns and age groups is crucial for orthodontic treatment.