Soft tissue and cortical bone thickness of orthodontic miniscrew site

Objectives: The mid-palatal suture area and maxillary interdental area are suitable site for the placement of orthodontic mini-implant. The purpose of this study was to provide a guideline to indicate the best location for mini-implant placement as it relates to the thickness of soft tissue and cortical bone. Method: Fifteen maxilla from 15 cadavers were cut in mid-sagittal plane and buccopalatal plane to measure the thickness of soft tissue and cortical bone of mid-palatal and maxillary posterior interdental areas. Sectioned samples were scanned and the thickness were measured. Results: Soft tissue thickness at the midpalatal suture area was 1.62 mm at 15 mm from the interdental papilla and remained uniformly thick posterior to this point, and steeply increased at 35 mm area posteriorly. Cortical bone thickness were greatest (2.01 mm) at 20 mm from the interdental papilla and remained uniformly thick posterior to this point, and decreased at 35mm area posteriorly. Palatal soft tissues thickness in all groups was thinnest at the 2 mm from the alveolar crest and gradually increased from alveolar crest to apical portion. Cortical bone thickness in all groups was thickest at the 1 mm from the alveolar crest and slightly decreased from alveolar crest to apical portion. Buccal soft tissue thickness in all groups was thickest at the 1 mm from the alveolar crest and gradually decreased from alveolar crest to apical portion. Cortical bone thickness was thinnest at the 1 mm in groups 1 and 3 and at the 2 mm in group 2 from the alveolar crest and slightly increased from alveolar crest to apical portion. Conclusion: Soft tissue thicknesses were greater on the palatal side than on the buccal side. Cortical bone thicknesses were similar between the palatal side and the buccal side.