Effect of experimental occlusal hypofunction on the three-dimensional microarchitecture of mandibular bone in rats / 中华口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effects of experimental occlusal hypofunction on the architecture of rat's mandibular bone.</p><p><b>METHODS</b>Forty Sprague-Dawley (SD) male rats were randomly divided into experimental occlusal hypofunction group and control group, with 20 rats in each group. Experimental occlusal hypofunction group rats were fitted with a metal cap to the maxillary and mandibular incisor, to eliminate the occlusal forces on rat molars. In control group, a metal ring was fitted to the maxillary and mandibular incisor to maintain molar occlusal contact. Then the rats were killed under deep anaesthesia at 0 week and at the end of 2, 4, 6, and 8 weeks, and the mandibles were immediately removed for measurement of the three-dimensional architecture of cancellous bone in the alveolar process with micro-CT.</p><p><b>RESULTS</b>At the end of week 4, the bone volume/total volume (BV/TV) in the hypofunction group decreased compared with the control group [control group(0.65 ± 0.05)%, experimental group (0.60 ± 0.05)%, P < 0.05] and lasted until the end of the experiment [control group (0.72 ± 0.06)%, experimental group (0.51 ± 0.07)%, P < 0.01]. The similar result was also observed in trabecula thickness (Tb. Th) in experimental animals [control group (168 ± 15), (170 ± 25), (180 ± 18) µm, experimental group (152 ± 20), (145 ± 19), (142 ± 15) µm, P < 0.05]. The trabecula spacing (Tb. Sp) in the hypofunction group increased from the end of week 4 to the end of week 8 compared with the matched control groups [control group (264 ± 21), (284 ± 17), (282 ± 26) µm, experimental group (306 ± 30), (316 ± 18), (332 ± 18) µm, P < 0.05]. The trabecula number (Tb.N) of experimental animals decreased from the end of week 6[control group(3.59 ± 0.22) mm(-1), experimental group (3.03 ± 0.31) mm(-1), P < 0.05] to the end of week 8[control group (3.66 ± 0.24) mm(-1), experimental group (2.85 ± 0.18) mm(-1), P < 0.01].</p><p><b>CONCLUSIONS</b>Experimental occlusal hypofunction can result in the change of mandibular alveolar process three-dimensional architecture.</p>