Objective:To investigate bioactivity,biodegradation,bone conductive properties,and clinical maneuverability of a novel injectable chitosan microspheres/ calcium phosphate cement(CPC).Methods: The bone defect of ??4 mm?4 mm?6 mm was made at both thighbones of 12 rabbits,and experimental material(chitosan microspheres/CPC) or control material(?-tricalcium phosphate cement,?-TCP) was injected into the defect respectively.The filling situation was evaluated by X-ray 3 days after operation.The rabbits were divided into three groups,four for each group.The samples with chitosan microspheres and the control with ?-TCP were collected at 8,16,24 weeks after operation.Histological examination and scanning electron microscope(SEM) evaluation were performed.Results: The absorption of implants with chitosan microspheres was observed at 8 weeks,and became more apparent at 16 weeks.Different size of cavities were observed in CPC after the degradation of chitosan microspheres.The chitosan microspheres/CPC was dramatically degradated after 24 weeks with a few chitosan microspheres,and new bone replaced the degradated materials.The implants with ?-TCP were absorbed slowly compared with the chitosan microspheres/CPC.The cavities in ?-TCP were small.Conclusion: The chitosan microspheres/calcium phosphate cement has the characters of good biocomptable and osteocombinative ability.Compared with the control material,adding chitosan microspheres into CPC could enhance its degradability and facilitate the new bone formation.

BACKGROUND: Fiber post is widely used in front teeth aesthetic repair, but some defect teeth cannot form ferrule or thick root canal, which resulted in fiber post prosthetic replacement defluxion and a failure of repair. Presently, new-style resin cement had self sticking component, showing good effects in sticking of fiber post. Whether combination of new-style resin cement can repair affected teeth using fiber post deserves further investigation.OBJECTIVE: Through fatigue test, residual flexural strength and scanning electron microscope (SEM) observation to compare the strength of severely weakened roots restored with three resin cements. METHODS: Eighteen intact maxillary central incisors were collected and formed to severely weakened canals at the same size. Three kinds of resin cements were used to restore. Rely X Unicem, Panavia F and Super-Bond C&B resin cement and identical glass fiber post were used. All the specimens were restored using Ni-Cr ceramic crown, and placed on TCML chewing machine that loaded 1 200 000 cycle forces, and the cycle times when failure occurred were recorded. The samples were intact following loading received residual flexural strength testl SEM was employed to observe breakage surface of the samples. RESULTS AND CONCLUSION: Mean cyclic loading was significantly greater in the Super-Bond C&B Group (1 200 000 times) than in the Relyx Unicem Group (640 000 times) and Panavia F Group (550 000 times) (P< 0.05). No significant difference was detected between the Rely X Unicem and Panavia F Groups. Residual flexural strength was 747.99 N in the Super-Bond C&B Group. SEM demonstrated that Super-Bond C&B formed longer resin processes, which were more than other two groups. Results confirmed that Super-Bond C&B demonstrated better results when restoring flared roots with prefabricated glass fiber posts.

Face ; physiopathology ; Humans ; Mouth ; physiopathology ; Pain ; Pain Threshold ; Somatoform Disorders

Objective:To investigate varied electromyographic types in the patients with hemimasticatory spasm(HMS).Methods:Surface electromyography was recorded to study electromyographic features of 16 cases with HMS.Results:Spasm was found in mandibular rest position in 2 cases and in tooth contact position in 14 cases.During the involuntary spasm of the 14 cases, motor unit potential could be classified into three types:continuous(8 cases), rhythmic(3 cases) and irregular(3 cases).Conclusion:The electromyographic feature of hemimasticatory spasm is characterized by continuous motor unit potential discharge. The spasm is mostly triggered by tooth contact.

Objective:To make a within-subject comparison of masticatory function and pattern between complete denture(CD)and implant-supported overdneture(IOD).Methods: Three edentulous patients volunteered to take part in this test.Each of the patients was rehabilitated with lower CD first and lower IOD later,and with the upper denture of CD.The masticatory efficiency,mandibular movement trace and the surface electromyograph (EMG) of masseters,anterior temporlis and posterior temporlis were measured 3 month after the use of each set of the dentures.Results: With IOD,each patient increased masticatory efficiency,especially when chewing almond.The regulation of chewing cycle,centralization of end traces and occlusal slides of mandibular movement were significantly improved.The electricactivity of masseters,anterior and posterior temporlis all enhanced by means of increasing contract intensity and the rhythm of the mastication was more regular.The muscle activity pattern in two cases transformed from instable to stable,while that of the another patient changed from masseter preponderant pattern to temporlis preponderant pattern.Conclusion: Patients with IOD have a heigher masticatory efficiency,more regular mandibular movement pattern,more effective masticatory muscle contractive pattern and masticatory muscle coordinative pattern than those with CD.

0.05).The dental plaque detactable rate of abutment teeth was higher than that of the controls(P

Objective:To evaluate diagnostic sensitivity of electroneurography(ENoG) for facial neurotmesis.Methods:The data of 24 patients suffering from facial neuratmesis on one side,having non-emergency operation,and having preoperative records of ENoG were collected.Among the patients,18 were men and 6 were women,aged from 3 to 55 years(median 28).The duration of injury before ENoG examination was from 1 to 56 days(mean 23.6 days) for them.The electroneurographic examination was carried out for facial nerves on both sides preoperatively.Percentages of evoked potential amplitude reduction on affected sides were calculated according to the value of normal side.The 90% reduction of amplitude was used as a cutting point.The facial neuratmesis was observed during operation.The sensitivity and false negative proportions of ENoG were analyzed.Results:Among the 24 patients with facial neurotmesis,22 had ENoG amplitude reduction over 90%,and 2 having this reduction less than 90%.The sensitivity and false negative proportions of ENoG in patients with facial neurotmesis were 91.7% and 8.3% respectively.Conclusion:The preoperative ENoG examination is high sensitivity for facial neurotmesis.The patients whose ENoG reduction over 90% should be advised to have a facial neurorrhaphy as soon as possible.

砄bjective: To explore an effective method for Electroneurography(ENoG) of facial nerve. Methods: ENoG of 114 normal subjets and 69 patients with traumatic facial nerve injuries were investigated. Latency time(LT), duration time(DT), amplitude(A) and square under the curve(S) were measured in facial muscles when facial nerve was stimulated postauricularly or anteroauricularly. Results: In most facial musles except square muscle of lower lip postauricular stimulation gave longer LT, shorter DT, lower A and smaller S. Conclusion: The postauricular stimulation is effective prior to anteroauricular stimulation for electroneurography of the facial nerve.

Objective:To construct of 3-dimensional finite element models of mandibular first molar with structure defect restoration.Methods:Reverse engineering technology was used. Geometric models were built by the use of advanced 3-dimensional laser scanning and computer assisted 3-dimensional design technique. The geometric data were introduced into the finite element software for establishing the finite element mesh after being processed.Results:The 3-dimensional finite element models of the minimum distal occlusal structure defect with restoration were created, which included metal crown with exterior anatomic morphology of the mandibular first molar, tooth preparation, filling material and the structure of periodontal membrane.Conclusion: The method may be a useful approach for building models of teeth and relative tissues.

Objective:To explore a method for setting up three dimensional finite element model of posterior glass fiber reinforced composite resin-bonded-fixed-partial dentures (GFRC-RBFPD) including restoration, periodontal tissue and alveolar bone. Methods:A stone model was fabricated including abutments and pontic of restoration, then it was scanned with laser scanner. Acquired data were integrated in Geomagic 5.0. Basic 3D geometric model was established. Different parts of abutement and prosthesis were designed in I-DEAS 10 NX Series and Geomagic, then periodontal tissue and alveolar bone were set up in Geomagic 5.0. Completed 3D geometric model was input into MSC.Marc Mentat 2003 for mesh generation. Boundary conditions were defined. Model was calculated in Mentat 2003. Results:3D geometric model and finite element model including GFRC-RBFPD, abutments, periodontal membrane and bone (bone lamina dura,cortical bone and cancellous bone) were established.Little contour information was lost, comparability between models was improved.Conclusion:The 3-dimensional laser scanning technique, CAD and mesh generation technique are effective in the establishment of 3-dimensional finite element model of GFRC-RBFPD.