The effects of tooth extraction on alveolar bone biomechanics in the miniature pig, Sus scrofa

Abstract

Objective This study investigated the role of occlusion in the development of biomechanical properties of alveolar bone in the miniature pig, Sus scrofa. The hypothesis tested was that the tissues supporting an occluding tooth would show greater stiffness and less strain than that of a non-occluding tooth. Design Maxillary teeth opposing the erupting lower first molar (M1) were extracted on one side. Occlusion developed on the contralateral side. Serially administered fluorochrome labels tracked bone mineralization apposition rate (MAR). A terminal experiment measured in vivo buccal alveolar bone strain on occluding and non-occluding sides during mastication. Ex vivo alveolar strains during occlusal loading were subsequently measured using a materials testing machine (MTS/Sintech). Whole specimen stiffness and principal strains were calculated. Results MAR tended to be higher on the extraction side during occlusion. 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; p=0.04); however, ex vivo shear strains showed no significant differences between sides. Stiffness differed between extraction and occlusion side specimens, significantly so in the low load range (344 vs. 668MPa, respectively; p=0.04). Conclusions 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 big overall change in specimen stiffness that was observed was likely attributable to differences in the periodontal ligament rather than alveolar bone.

The impact of occlusal function on structural adaptation in alveolar bone of the growing pig, Sus Scrofa

“…Mandibular torsion or bending during mastication may promote adaptive change of alveolar bone in pigs, and occlusal function may be only a minor factor in determining alveolar bone structure. Although maxillary tooth extractions resulted in greater alveolar strains on occluding side jaws, there were still substantial alveolar strains in the non-occluding side during chewing 12. Masseter muscle activity in conjunction with occlusion of anterior teeth may result in torsional deformation of the mandible during chewing and could account for the strain levels in alveolar bone supporting non-occluding teeth 13.…”

“…The effect of tooth extraction surgeries on the masticatory system has been described previously 12. Electromyography was used to track chewing activity before and after tooth extraction.…”

Alveolar ridge reduction after tooth extraction in adolescents: An animal study

“…Based on indirect evidence, however, we reason that a functional overloading at the non-extraction site is less likely. The tooth extracted in this study (dm2) is relatively small (indicated by low strain values in Table 2 compared to those from a molar location (21)) and likely not so functionally critical as to require compensatory overactivity of the non-extraction side. Lack of compensation is supported by the fact that pigs did not favor the non-extraction side during chewing (Fig.…”

“…With this value included, the IE-extraction site measurements showed a coefficient of variation of 1.062, and with it excluded, the coefficient of variation was 0.698 (Table 2). Previous studies on bone surface masticatory strain measurements from the pig report coefficients of variation values in a range of 0.2–0.7 (21, 30, 33). In the SE group, strain was nearly identical between the extraction and non-extraction sites (2-sample t-test, p = 0.846) and the coefficient of variation was less than 0.7 at both sites.…”

“…Specifically, it remains uninvestigated whether the local alveolar ridge is functionally unloaded after tooth extraction. Recently, it was found that alveolar bone lacking direct occlusal contact still sustains mechanical loading (21), suggesting that the disuse atrophy mechanism of RRR is open to question.…”