[Comparison of dentinal microcracks caused by new generation of single reciprocating files after root canal preparation].

PURPOSE: To compare the incidence of dentinal microcracks after root canal preparation by new generation of nickel-titanium instrument WaveOne Gold, Reciproc Blue with previous WaveOne and Reciproc. METHODS: Ninety extracted single-rooted mandibular premolars were randomly divided into 6 groups(n=15). The root canals were instrumented by using Hand K files, WaveOne, Reciproc, WaveOne Gold and Reciproc Blue. Fifteen teeth were left unprepared and served as negative controls. The root canals were all prepared to 25#. The roots were then sectioned at 3 mm, 6 mm and 9 mm from the apical orifice using a hard tissue slicer. The slices were observed under stereoscopic microscope at ×25 magnification. SPSS 17.0 software package was used for statistical analysis. RESULTS: No dentinal microcrack was found in the hand K files group and negative control group. The reciprocating single files WaveOne, WaveOne Gold, Reciproc and Reciproc Blue all produced dentinal microcracks after root canal preparation. The WaveOne generated the most dentinal microcracks than the hand K files(P＜0.05), and the microcracks were mainly concentrated in the middle part of the root. The number of dentinal microcracks caused by Reciproc and Reciproc Blue was the same, with no significant difference(P＞0.05). CONCLUSIONS: The new generation of reciprocating files of WaveOne Gold and Reciproc Blue may not increase the incidence of dentinal microcracks after root canal preparation.

[Effects of fluoride on expression of survivin during rats' dental germ development].

PURPOSE: This study was to investigate the expression of survivin in dental germ development of SD rats with fluorosis, and explore the effects of fluoride on survivin expression and the pathogenic mechanism of dental fluorosis. METHODS: Forty-five SD rats (pregnant for 10 days) were randomly divided into control group, experimental group 1 and group 2. Drinking water with fluoride concentration of 0, 50, 150 mg/L was provided for rats accordingly. The samples were collected at E18.5th day, E20.5th day, P1.5th day, P3.5th day and P5.5th day, then the samples of P1.5th day were selected for H-E staining. SABC method was used for immunohistochemical analysis of samples in each group. The images were acquired by Motic Med 6.0 digital medical image analysis system, and the data were analyzed for ANOVA with SPSS 13.0 software package. RESULTS: Survivin expression fluctuated and exhibited 'M' shape (rose first and fell later) in each group.There was no significant difference at E18.5th day (F=1.050, P>0.05) and E20.5th day (F=2.232, P>0.05) between each group. There were significant differences at P1.5th day (F=3.538, P<0.05), P 3.5th day (F=3.820, P<0.05) and P5.5th day (F=5.096, P<0.05) between the control and experimental groups. The postnatal rats in each group were evaluated by SNK method for surviving expression. There was no significant difference between control group and experimental group 1 (P>0.05). However, there was significant difference between control group and experimental group 2 (P<0.05). CONCLUSIONS: The results suggest that fluoride can decrease the expression of survivin in the postnatal rats with higher fluoride concentration, which may be the mechanism in the development of dental fluorosis.

[Observation on therapeutic effect of round-sharp needle of new nine-needle and elongated needle for piriformis syndrome with triple puncture method].

OBJECTIVE: To compare the efficacy differences between round-sharp needle of new nine-needle and elongated needle for piriformis syndrome, and explore its action mechanism. METHODS: Eighty cases were randomly divided into a round-sharp needle of new nine-needle group (round-sharp needle group) and an elongated needle treatment group (elongated needle group), 40 cases in each group. The round-sharp needle group was treated with round-sharp needle (0.60 mm x 125 mm) at three points in piriformis with triple puncture method, while the elongated needle group was treated with elongated needle of ordinary specifications (0.32 mm x 125 mm) at three points in piriformis with triple puncture method. Besides, the two groups were also treated with routine acupuncture at Weizhong (BL 40) and Yanglingquan (GB 34), 3 times every week, 2 weeks as one course of treatment. After one course of treatment, the clinical effect was evaluated and the pain threshold values were measured before and after treatment in the two groups. RESULTS: The total effective rate in the round-sharp needle group was 92.5% (37/40), which was superior to 77.5% (31/40) in the elongated needle group (P < 0.05). Compared before treatment, the pain threshold values after treatment in two groups were improved significantly (both P < 0.01). The increment of pain threshold value in the round-sharp needle group was higher than that in the elongated needle group (P < 0.01). CONCLUSION: Round-sharp needle of new nine-needle is effective in treatment of piriformis syndrome and is better than ordinary elongated needle, which is related to that it can effectively increase pain threshold value of the local tissue.

[A study of oral health behaviors among 65 to 74 years old people in Shanxi province].

PURPOSE: To assess the oral health behaviors among 65 to 74 years old people in Shanxi province, and provide a base line for oral health service. METHODS: Four hundred and five old people aged from 65 to 74 in Shaanxi province was selected according to the Third National Oral Health Investigation Criteria and the oral health behaviors of them were investigated by questionnaire. SPSS 13.0 software package was used for statistical analysis. RESULTS: Of the participates, 14.3%, 6.6%, 39.5% of old people ate dessert, candy/chocolate, sugar-containing dairy products every day, and 27.5%, 17.0%, 0.7%, 0.5% drank fresh fruit, saccharine, fruit juice, carbonated drinks once daily, respectively. Compared with the rural areas,the proportion of people who drank fresh fruit or ate dessert, sugar-containing dairy products once daily was higher in the urban area (P<0.01). The proportion of people who significantly smoked cigarette, drank alcohol, or drank tea every day was 31.4%, 33.8% and 70.6%, respectively. Smoking and tea consumption were more prevalent in the urban area as well as in males(P<0.01). No difference was found between the prevalence of drinking alcohol in the urban and rural area(P>0.05), but more males drank alcohol than females(P<0.01). 55.8% of people brushed their teeth more than one time a day. Among the investigated people, about 80% never used the toothpick;only 0.7% of them used dental floss;About 30% of the investigated people used fluorine-contained toothpaste, more of them in the urban areas (P<0.01). Fluorine toothpaste usage was 29.1%, significant difference was found between in the urban and rural area (P<0.01), but no significant difference was noted between in males and females(P>0.05). CONCLUSION: Oral health behaviors of 65 to 74 years old people in Shanxi province is irrationality, and needs to be adjusted and improved.