Objective: To analyze the influence of different inclination of cusp on the stress of an implant supported denture. Methods: A spiral CT was used to scan a corpus' head.The model of mandible,teeth and implant was established by ANSYS 6.1 software. The superstructure of the denture had three different inclination of cusp.The stress distribution of the models under loading was analyzed. Results: When bearing non central loading, the maximum equivalent stress (max EQV) of the abutment was situated at the first screw of the abutment.When bearing central loading, the maximum equivalent stress(max EQV) of the abutment was situated at the cervix. Under all loading, the max EQV of the implant was situated at the cervix, the max EQV of mandible was situated at the upper cortical layer around the cervix of the implant. Higher inclination of cusp and non central loading lead to higher stress. Conclusion: The location of the max EQV of the abutment is consistent with the location of the abutment fracture; lower inclination of cusp and flatsurface teeth are benefit to the stress distribution of the implantation.

Carcinoma, Neuroendocrine ; pathology ; Humans ; Nasal Cavity ; pathology ; Nasopharynx ; pathology

OBJECTIVETo study the clinical effect of the functional muscular equal pressure zone on complete denture.

METHODSArtificial teeth were arranged within the functional muscular equal pressure zone. With this technique 35 complete dentures were made to rehabilitate 35 edentulous patients whose alveolar bones were moderately or seriously absorbed. After three months' following up, the satisfaction of these patients were investigate.

RESULTSAfter prosthesis treatment, 35 patients enunciated well and the aesthetic effect was favorable. 89 percent of these patients satisfied the retention and the stability of the maxillary denture, and 78 percent satisfied the retention and the stability of the mandibular denture. 79.5 percent of these patients satisfied the mastication efficiency.

CONCLUSIONWith the technique, the complete denture is fairly stable in patient's mouth. The technique can enhance the denture's retention and improve the patient's mastication efficiency, especially to these whose alveolar bones are moderately or seriously absorbed. Clinically the technique is of high practical value to these edentulous patients who are difficult to be rehabilitated.

Aged ; Aged, 80 and over ; Bite Force ; Dental Occlusion ; Denture Design ; methods ; Denture Retention ; Denture, Complete ; Evaluation Studies as Topic ; Female ; Humans ; Male ; Middle Aged ; Mouth, Edentulous ; therapy

OBJECTIVETo study the influence of three kinds of retainers on the abutment movement of removable partial dentures (RPDs) for restoring the dentition with unilateral distal-extended tooth missing.

METHODSThe combined clasp, the extension clasp and the telescopic crown were designed to retain RPDs. When food chip was masticated between dentitions, the displacement of abutments was measured by a high-sensitive-laser-transferring-detector, and then the data was statistically analyzed.

RESULTSAll of abutments showed the inclination, torsion and vertical translocation. Of them, abutments with telescopic crowns had the lowest horizontal torsion (P < 0.01) and the highest vertical translocation (P < 0.01).

CONCLUSIONSCompared with the combined clasp and the extension clasp, the telescopic crowns enable abutments to bear the load more axial and the stress to be distributed more even, so the design of the telescopic crown may be considered more favourable for the health of abutments.

Crowns ; Dental Abutments ; Dental Clasps ; Dental Stress Analysis ; methods ; Denture Retention ; instrumentation ; methods ; Denture, Partial, Removable ; Humans ; Tooth Movement Techniques

Objective To evaluate the effect of isoflurane on the expression of hippocampal ubiq-uitin C-terminal hydrolase-L1(UCH-L1)mRNA in aged rats. Methods Thirty-six pathogen-free healthy male Sprague-Dawley rats, aged 20 months, weighing 500-700 g, were divided into 2 groups using a ran-dom number table: control group(group C, n=12)and isoflurane group(group I, n=24). In group I, 2% isoflurane was continuously inhaled for 2 h. Twelve rats were selected at 24 and 72 h after stopping isoflurane inhalation(T1,2), and Y-maze test was performed to evaluate cognitive function. The animals were sacrificed after the end of Y-maze test and their hippocampi were removed for determination of UCH-L1 expression(by immuno-histochemistry)and UCH-L1 mRNA expression(by real-time polymerase chain reaction). Results Compared with group C, the total number of training achieving the standard was sig-nificantly increased at T1(P<001 or 005), and the expression of UCH-L1 mRNA was down-regulated, and no significant change was found at T2in group I(P>005). Conclusion The mechanism by which isoflurane induces cognitive decline may be related to down-regulating the expression of UCH-L1 mRNA in hippocampal tissues of aged rats.