Evaluation of the infrazygomatic crest and mandibular buccal shelf in different sagittal skeletal patterns: a cone-beam computed tomography study

To compare bone thickness, bone height, and density in the infrazygomatic crest (IZC) and the mandibular buccal shelf (MBS) associated with different sagittal skeletal patterns. This retrospective study included three groups of which a Class I group consisted of 28 patients (24 female, 4 male, mean age: 26.46 ± 6.1), a Class II group comprised 31 patients (28 female, 3 male, mean age: 30.08 ± 5.9), and a Class III group included 26 patients (22 female, 4 male, mean age: 26.21 ± 5.3). Evaluations of bone characteristics were performed for both the IZC and MBS using cone-beam computed tomography (CBCT). Maxillary length and mandibular body length were also measured on lateral cephalograms. One-way ANOVA, chi-squared, and Spearman’s correlation tests were applied for statistical analysis. The Class II group showed significantly greater bone thickness at the distal root level of the maxillary second molar in IZC (p < 0.05). While bone thickness showed no statistically significant difference in the MBS between the groups (p > 0.05), the Class II group showed significantly higher bone height values at the distal root level of the mandibular second molar in the MBS (p < 0.05). A statistically significant increase from the mesial aspect to the distal aspect was observed in total bone thickness in the Class I group and total bone thickness and height in the Class II and III groups in the MBS. The mandibular body length and SNB values were positively correlated with the total bone thickness and bone height of the MBS. Bone thickness in the IZC and bone density in both the IZC and MBS were similar in the different sagittal skeletal patterns. Total bone thickness in the Class I and III groups and the total bone height in the Class II group showed a gradual increase from the mesial to the distal in the MBS. The length of the mandibular body may be a clinical clue to assist in the selection of the appropriate implantation area.