The effect of orthodontic extrusion on alveolar bone – a prospective clinical study

Abstract

Introduction/Objective Orthodontic extrusion is the procedure for moving the teeth in a vertical, coronal direction. This movement induces changes in the periodontal ligament and the production of new alveolar bone. The objective of the study was to determine the changes on buccal, palatal and interdental alveolar bone as a result of orthodontic extrusion.

Methods Experimental group included six patients who received orthodontic treatment with the fixed appliances; the control group included four patients without orthodontic treatment. Two cone-beam computed tomography scans (initial and final) were obtained for each patient in both groups. Length of a tooth, shortest distance from tooth’s center of resistance to the referent plane, distance from buccal or palatal plate tip to the enamel-cement junction, the height of interdental septum, buccal and palatal plate vertical gain, buccal and palatal plate thicknesses were measured on initial and final scan in the experimental and control group.

Results The reduced length of the extruded tooth was observed in the experimental group. The distance from buccal and palatal plate tip to the enamel-cement junction, mesial interproximal bone septum and buccal plate gain significantly increased in the experimental group. No significant difference was found in the distal interproximal bone septum, palatal plate gain and buccal/palatal plate thickness between groups.

Conclusion Orthodontic extrusion affects alveolar bone level by gaining the hard tissue buccal and mesial of extruded teeth, while buccal and palatal plate thickness insignificantly changed.

Keywords: orthodontic extrusion; alveolar bone level; CBCT