[The effects of dentists'performance on the clinical effects of root canal preparation].

PURPOSE: To evaluate the effects of dentists'performance on the clinical efficacies of root canal preparation. METHODS: 164 teeth, including 66 vital teeth and 98 necrotic pulp teeth , were divided into two groups in random. All the root canals were prepared using ProTaper nickel-titanium rotary by two dentists with junior senior qualification. The incidence of instruments fracture, endodontic interappointment pain (EIP) and successful rates of root canal filling of the two groups were compared by X(2) test with SAS 6.2 software package. RESULTS: Between the two groups, the difference of the incidence of instruments fracture in molar was significant (P<0.05). The incidence of EIP between the two groups had high significant difference (P<0.01); The difference of vital teeth and necrotic pulp teeth was significant (P<0.05) in junior dentist group. The successful rates of root canal filling had significant differences (P<0.05), especially in necrotic pulp molar teeth. CONCLUSION: Skilled and accurate operation can improve the clinical efficacies of root canal preparation.

[A study on the accuracy of electronic root canal length measurement and its influential factors].

PURPOSE: To study the accuracy of JUSTY-II electronic apex locator and the influential factors on the accuracy of root canal working length measurement. METHODS: 148 teeth, including 71 teeth with pulpitis, 46 with necrotic pulp and 31 with apical periodontitis, were divided into two groups in random. The accuracy of electronic root canal working length measurement group was compared with that of the manual measurement group by Chi(2) test. The influence of clinical types, root canal in dry or moisture conditions and root canal preparation on the accuracy of root canal working length measurement was analyzed. RESULTS: The accuracy of electronic apex locator was 87.84%, while it was 43.24% in manual measurement, the difference was significant (P<0.01). The accuracy in the group of apical periodontitis was significantly lower than that of the other groups (P<0.05). Root canal in dry or moisture conditions had no effect on the accuracy of root canal length measurement, but root canal preparation could decrease the accuracy of measurement (P<0.05). CONCLUSION: Electronic apex locator is an accurate and convenient device in measurement of root canal working length. Apical periodontitis and root canal preparation can decrease the accuracy of measurement.

[Clinical study of the effect of preventing dentine hypersensitiveness by using Fluor Protector and Green Or on the prepared vital pulp abutment teeth].

PURPOSE: To study and evaluate the effect preventing dentine hypersensitiveness by using Fluor Protector or Green Or on the prepared vital pulp abutment teeth of PFM bridges. METHODS: 118 cases, 246 prepared vital pulp abutment teeth, were randomly divided into three groups: Experimental Group A--treated with the Fluor Protector and temporary crown; Experimental Group B--treated with the Green Or and temporary crown, and Control Group--only using temporary crown. The results of desensitization in 3 groups were evaluated. F test was used for analysis (DSPV6.01). RESULTS: Significant differences were found between experimental Group A, B and the control group after 1 week (when cementing the PFM bridges); and also after 1 month (P<0.05). But no significant difference was found between experimental Group A and B (P>0.05). CONCLUSIONS: The effect of preventing dental hypersensitiveness by using Fluor Protector or Green Or on the prepared vital pulp abutment teeth of PFM bridges is ideal. It is easy to use and worth being widely applied.

[A comparison of the effect between Vitapex paste and antibiotic paste in apexification.].

PURPOSE: To study the effects of two root canal filling material in the apexification. METHODS: 172 juvenile permanent teeth,including 62 teeth with pulpitis, 32 teeth with necrotic pulp and 78 teeth with periapical periodontitis, were divided into two groups.The root canal was filled with Vitapex paste and antibiotic paste.Every patient was examined once three months.The treatment lasted 6-30 months.The outcome of treatment was investigated for three years following treatment. RESULTS: The effective rate in the group of Vitapex paste and antibiotic paste group were 86.0% and 91.9% (P>0.05).In periapical periodontitis group,the effective rate of antibiotic paste group was significantly higher than the other (P<0.05). CONCLUSION: Both Vitapex paste and antibiotics paste were good filling materials in apexification. Antibiotic paste was better than the other in periapical periodontitis group.