ABSTRACT
To observe repair of dental defect and its curative effect of the vertical root split of molar in the seniors, every affected section of 36 cases (40 teeth) of the senior's root split was extracted by hemisection, the other sections of them were repaired by either complete crown restoration (15 cases) or fixed bridge restoration (21 cases). The results showed that after 6～12 months, excellent curative effect was achieved in 32 cases, good curative effect in 3 cases, poor curative effect in 1 case. Significant difference was found between the two repair methods( P
ABSTRACT
Objective To study the effect of hemisection in the treatment of the molars. Methods 136 molars were selected and hemisection technique were used. If the pathological change was concentrated to the root, such as periodontics, apical inflammation, root fractures, the pathological root was extracted. If the pathologicalchange was concentrated to the divergence of the roots or the bottom of pulp chamber, hemisection was performed. then all the tooth was restoredwith fixed restoration according to the solid conditions. Results These were followed up and evaluated in three years 94. 85% of the all molars were treated satisfactory. Conclusions The hemisection techniqueoperation is simple, but the indications are extensive,and its effect in the treatment of the molars is regarded as a positive method
ABSTRACT
In order to study the stress distribution and displacement characternstic of the temporomandibular joint (TMJ) during centric occlusion, using the three dimensional nonlinear finite element model of normal human TMJ developed from in vivo with simulation of the contact relationship within TMJ, the stress and the maximum displacement of various structures in the TMJ were calculated and analyzed during centric occlusion. Furthermore, we separately accounted the mechanical properties of various structures in human TMJ and three dimensional muscle force vectors of their masticatory muscles measured and analyzed by use of the fusion of cranio jaw facial CT and MR image with the multiresolution method based on wavelet pyramid. The results showed that there were significant differences in the region and value of stress distribution on the surface of the disc, condyle and articular fossa during centric occlusion, in which the biggest stress was distributed in the condyle, the second in the articular fossa, and the smallest in the disc. During centric occlusion, the disc, condyle and articular fossa moved upperly, posteriorly and medially with the biggest displacement on the condyle, the secondary one on the disc and the smallest one on the fossa. It suggested that it is clinically feasible to systematically and rationally calculate and analyze the stress distribution and displacement character, and the results were satisfying