Meeting Abstract
90.3 Thursday, Jan. 7 The Effect of Occlusion on Alveolar Bone Biomechanics in the Miniature Pig, Sus scrofa YEH, K.D.; POPOWICS, T.*; RAFFERTY, K.; HERRING, S.; University of Washington, Seattle popowics@u.washington.edu
This study investigated the role of occlusion in the biomechanical properties of alveolar bone in the miniature pig, Sus scrofa. The hypothesis tested was that the periodontium supporting an occluding tooth would show greater stiffness and less strain than that of a non-occluding tooth. Teeth opposing the erupting lower first molar (M1) were extracted on one side and occlusion was allowed to develop on the contralateral side. A terminal experiment measured in vivo buccal alveolar bone strain on occluding and non-occluding sides. Ex vivo alveolar strains were measured on mandibular segments through application of axial compression at 0.3mm/s until 890N using a materials testing machine (MTS/Sintech). Principal strains were calculated at 890N, and whole specimen stiffness was calculated at low load (200-445N) and high load (445-890N) ranges. In vivo buccal shear strains were higher in the alveolar bone of the occluding side vs. the extraction side (mean of 471µε vs. 281µε, respectively; Wilcoxon signed ranks test, p=0.04). Ex vivo shear strains, however, showed no significant differences in magnitude between sides. Stiffness differed significantly between extraction and occlusion side specimens in the low load range (344 vs. 668MPa, respectively; Wilcoxon signed ranks test (p=0.043), but were similar within the high load range (935 vs. 1216MPa). Greater in vivo shear strains may indicate more forceful chews on the occluding side, whereas the similarity in ex vivo bone strain magnitude suggests a similarity in alveolar bone structure and occlusal load transmission regardless of occlusal status. The greater stiffness of occluding side specimens at low loads, however, indicates fortification of the periodontal ligament to resist occlusal loads. Supported by NIH/NIDCR DE 015815.
