The Characteristic Analysis of Mandibular Third Molar Space in Patients with Different Antero-Posterior Skeletal Patterns / 天津医药

ABSTRACT

Objective To compare the retromolar space (RMS) between different antero-posterior (A-P) skeletal patterns, and explore the relationship between the status of third molar eruption/impaction with the different A-P skeletal patterns. Methods A total of 90 orthodontic patients (25-35 years old) were investigated from dental pantomograms (DPTs) and lateral cephalograms (LC). The subjects were divided into three groups according to their ANB angle:skeletal classⅠ, skeletal classⅡ, and skeletal classⅢ. Each group was subdivided into impacted and erupted subgroups. Values of DPT and LC were traced, and the following variables were measured including mandibular body length, third molar angulation and ret-romolar space width. Results The retromolar space width was significantly smaller in classⅡsubjects than that in classⅢsubjects, and RMS was significantly smaller in impacted group than that in erupted group, respectively (P<0.05). There was no significant difference in the mandibular angle in erupted subgroup (P<0.05). There was a smaller mandibular body length in impacted subjects (P<0.05). Conclusion There is a relationship between different morphological characteristics of sagittal skeletal pattern and the impacted status. Patients with shorter mandibular body length and decreased RMS width are more inclined to impaction.