Occlusion is a term for the contact relation between upper and lower dentitions.It is a three dimensional relationship.The vertical occlusal contact relation includes convex-to-concave contact relation between structures on occlusal surfaces of the upper and lower teeth at status of intercuspal occlusion,as well as that during protrusion,retrusion and lateral excursive movements.Occluding function depends on the contact condition of occlusion.However,the morphological criterion of the vertical occlusal contact is still lacking.Widely practical criterion for dental treatment includes only mesial-distal relation,such as one-to-two teeth contact relation between upper and low dentitions,and labial/buccal-lingual relation,such as over jet and over bite.To establish a vertical occlusal contact criterion that meets the need for individual occlusal treatment is one of the main subjects in Occlusion field.

0.05).(2)The relative tooth attrition:significant differences between CTS and control group in upper premolar lingual cusp and lower first molar buccal cusp were found.(3)Tooth cracked direction:it was mesial-distal direction in 91.67% maxillary premolar and 88.89% maxillary second molar in CTS but no obvious direction taxis in first molar and mandibular second molar in CTS.Conclusion:There are close correlations between insufficient tooth attrition in maxillary premolar lingual cusp,mandibular first molar mesial buccal cusp and CTS.

Objective:To investigate the effects of occlusal adjustment in the treatment of TMD . Methods: 7 cases of TMD were treated by occlusal adjusment and occlusal contact points were measured with T-scan II system before and after treatment . VAS pain analysis table was used to evaluate the pain control effect of occlusal adjustment method. Results:The number of occlusal contact points increased obviously after occlusal adjustment,and distribution of contact on two sides tended to be balanced.Pain release was indicated by VAS table . Conclusion: Occlusal ajustment method is necessary for the treatment of TMD

Objectives: To investigate the characteristics and their functional significance of TMJ disc and its attachment. Methods: Each of the 23 TMJs from 12 cadavers were divided into quadrants sagitall y, and total 92 histological slices were obtained and stained with HE.The morpho logical characteristics of the samples was observed microscopically. Results: ①Both temporal posterior and anterior mandibualr attachment s were loose while mandibular posterior and anterior temporal attachments were d ense in which the fibers run anterior posteriorly. ②Fibers in the intermediate zone ran predominantly in anterior posterior direction while those in both ant erior and posterior bands were mixed with transverse fibers. ③At the posterior portion of disc there were 33 out of 92 slices from 6/12 cadavers (11/23 TMJs) s howed the structure of "the fourth band" which was featured by dense fibers alik e those of inner disc. There were 36 out of 92 slices from 6/12 cadavers (10/23 TMJs) showed the structure of "turned fibers" which was featured by a sudden tu rning of fibers from the thick posterior band back and downward, providing an angle like sign. Conclusions: There is great difference o f fiber direction in various parts of disc and its attachments, reflecting the functional demands.

Objective: To investigate the expression and distribution of G protein and protein kinase C (PKC) under the mechanical pressure in rabbit mandibular condylar chondrocytes (MCCs) and to study the role of G protein in PKC signalling pathway. Methods:MCCs from two-week-old New Zealand rabbits were cultured. After treatment under continuous pressure of 90 kPa for 60 min or 360 min by hydraulic pressure controlled cellular strain unit, the expression of G?q/11 protein was examined by Western Blot. The expression and distribution of PKC was observed by immunocytochemical staining. Results:Gaq/11 protein in MCCs treated by 90 kPa for 60 min and 360 min was increased by 163.7% and 65.8% respectively(P0.05). PKC in control cells distributed uniformly in the cytoplasm. After been pressed under 90 kPa for 60 min,PKC translocated to the membrane and, partly,into nuclei. When the pressure prolonged to 360 min, PKC distributed uniformly again in cytoplasm. By treatment of G protein inhibitor, the translocation of PKC under 90 kPa of 60 min was not observed. Conclusion:Feasible pressure may promote G protein expression and activate PKC. The activation of PKC signalling pathway is mediated by G protein.

Objectives: To investigate the occlusion features in thre e dimensions in patients with temporomandibular disorders(TMD). Methods: Occlusal casts were obtained from 23 asymptom volunteers and 101 TMD pati ents and were analyzed in three dimensions by scores vertically, mesio-distally and labial-or buccal-lingually. Bilateral TMJs of each TMD patient was examin ed with Schuller's radiograph and tomograph, the sounding TMJs were examined wit h arthrography. The relationship between occlusion scores and the changes shown in X-ray images were analyzed. Results: 66.3% TMD patients had abnormal occlusion in vertical direction.Abnormal occlusion in vertical directio n was correlated with TMD symptoms(P 0.05 ). Conclusion: Abnormal occlus ion in vertical direction is correlated with TMD symptoms.

0.05).Conclusions:Occlusal splint is effective in the control of TMD pain,the treatment mechanism is related to the quick improvement of masticatory muscles.

Objective:To investigate the expression of estrogen receptor ? and ?(ER? and ER?) in temporomandibular joints(TMJs) of Sprague-Dawley rats.Methods:The expression of ER? and ER? in TMJs was examined by SABC technique of immunocytochemistry, meanwhile the co-expression of them was detected by double-staining technique of immunocytochemistry.Results:①Intense ER? and ER? immunoreactivity was localized in the hypertrophic layer of condyle cartilage,and some immunoreactivity was found in osteocytes of mandible and temporal bone. ②The immunoreactivity of ER? and ER? was found in both nuclei and cytoplasms. Most of immunoreactivity of ER? was localized in nuclei, while ER? was distrubuted more evenly. ③The expression of ER? was wider than that of ER?.Conclusions:TMJ is one of target organs of estrogen.The expression of ER? is different from that of ER?,which suggests there may be different mechanisms directed by ERs.

砄bjective:To elucidate the effects of gradually induced occlusal disorder on the expression of TGF ?1 in temporomandibular condyle of monkey. Methods:In a monkey after extraction of right upper first molar and left lower first molar, a fixed orthodontic appliance was used to cause the adjacent teeth inclined to the space and to occlude with opposite in coordinately. Another monkey was used as the control.8 months later, the animals were sacrificed and bilateral temporomandibular condyles were examined with histologic and immunohistochemical methods.Results:In the animal with teeth extraction, degenerative changes were found in anterior medial part of condyles, the thickness of condylar cartilage decreased significantly, especially in the anterior parts of medial and central thirds, and also the intermediate part of medial third ( P

砄bjectire: To investigate whether the disturbed occlusion can induce TMJ degeneration. Methods: 2 Rhesus female monkeys, 1 served as experimental animal and the other as the control, were included. Right mandibular first molar and left maxillary first molar of the experimental animal were extracted. Small strings were set at the missing space to pull the neighbor teeth inclined into the space and to occlude with opposite teeth in convex to convex relation. 8 months later condyles and discs of both animals were surgically obtained and prepared for scanning electron microscopy examination. Results: Gelatin like material was found over the condyle and disc surface of the control animal and obvious rigids were found on its articular surface. On the sagittal section of the condyle cells arranged in lines of each of the three layers of the soft tissue were observed. But on the top of the condyle surface of the experimental animal there was an area from media anterior to lateral posterior where the gelatin like material twisted or even disappeared here and there. There was an area where fibers were exposed. The soft tissue layers were thinner and the cellular layer was discontinued locally. The waves on the surface of middle and posterior part of the disc were disturbed and fossae like changes were found on the inferior surface. Conclusion: TMJ degeneration can be produced by gradually induced occlusal disturbance.