Assessment of the mandibular buccal shelf for orthodontic anchorage: Influence of side, gender and skeletal patterns

Abstract

Objectives: To evaluate bone height and thickness in the mandibular buccal shelf region and to compare differences between anatomical sites according to gender, side and vertical and sagittal skeletal patterns. Settings and sample population: Multislice computed tomography (MSCT) images of 94 subjects (51 females and 43 males) were previously obtained as part of preoperative planning for orthognathic surgery. Methods: Measurements were performed in three different regions of the mandibular buccal shelf: mesially, towards the central groove and distally to the second molars. Bone thickness measurements were obtained perpendicularly 3, 5 and 7 mm below the bone crest towards the mandible outer cortex. Bone height was measured 3 mm away from the bone crest perpendicularly to the outer cortex of the base of mandible. Results: There was an increase in bone thickness in the posterior and basal directions. The increase in bone thickness ranged from 1.8 to 7.1 mm. Greater bone height was found in the anterior direction. The increase in bone height ranged from 17.5 to 22.5 mm. Hypodivergent and Class III subjects showed significantly greater bone thickness (P < .05). Significantly greater bone height was found mesially to the second molar in Class III subjects compared with Class I subjects (P < .05) and in hyperdivergent males compared with hypodivergent males (P < .05). Conclusions: The region distal to the second molar is the most appropriate for the insertion of extra-alveolar mini-screws in terms of bone thickness. Hypodivergent and Class III subjects showed greater bone thickness in the mandibular buccal shelf region.

Tomographic Evaluation of Mandibular Buccal Shelf in Patients with Different Vertical Growth Pattern

“…In this study, the characteristics of the MBS were also evaluated according to sex and the side of the hermiarch, finding that there were no significant differences in both cases, which coincides with what was previously reported by other authors (14,15). Also, Farnsworth et al (24) observed that there was no difference in the cortical thickness of the mandibular alveolar bone between men and women.…”

“…Parinapucham et al (23) found that between hyperdivergent and normodivergent class III subjects, there were no differences for MBS cortical slope angle and bone thickness. While Aleluia et al (15) found that Class III hypodivergent subjects had greater bone thickness than the other groups.…”

“…Several studies on CBCT have found that the different sagittal and vertical growth patterns can influence the anatomy of certain structures, including the mandibular symphysis, the mandibular bone plate, and the cortical and alveolar bone (13)(14)(15). Growth variations in anatomical structures can determine a thicker or thinner cortical bone type (16), which would influence the insertion of extraalveolar miniscrews and their stability during orthodontic treatment (4).…”

Tomographic assessment of infrazygomatic crest bone depth for extra‐alveolar miniscrew insertion in subjects with different vertical and sagittal skeletal patterns

“…The few studies that have evaluated bone availability at the IZC showed that its depth may vary from individual to individual 5,6 . Skeletal patterns are known to be related to different bone structures 15‐19 ; however, bone availability according to different vertical and sagittal patterns in the IZC at different angles has not been investigated. The purpose of this study was to determine the bone depth in the IZC area between the maxillary first and second molars in Class I, II and III subjects with different vertical patterns by means of tomographic images.…”

“…[11][12][13][14] The few studies that have evaluated bone availability at the IZC showed that its depth may vary from individual to individual. 5,6 Skeletal patterns are known to be related to different bone structures [15][16][17][18][19]…”