[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.

Quality of Life in Patients After Maxillectomy and Placement of Prosthetic Obturator.

PURPOSE: The aim of this study was to assess quality of life (QoL) and obturator functioning in patients having undergone a maxillectomy as a tumor ablative resection and rehabilitation with a prosthetic obturator. MATERIALS AND METHODS: The University of Washington Quality of Life scale version 4 (UW-QoLv4) and the Obturator Functioning Scale (OFS) were used to evaluate the self-reported QoL and obturator functioning. The effects of demographic and treatment variables on QoL were assessed using age, defect size, postoperative radiotherapy (RT), neck dissection, and dentition. RESULTS: The study included 16 men and 13 women with a mean age of 48.8 years. Of the 29 patients, 16 had a Brown Class 2a or smaller defect and 13 had a Brown Class 2b or larger defect. The mean OFS score (P = .004) and the physical (P = .001) and social-emotional function scores (P = .001) of the patients who received postoperative RT were significantly lower than those who did not receive postoperative RT. The subscales for swallowing (P = .008), saliva (P = .001), pain (P = .001), and shoulder function (P = .002) correlated strongly with postoperative RT on the UW-QoL. The subscales for pronunciation (P = .007) and saliva (P = .002) correlated significantly with RT on the OFS. The mean OFS scores were significantly lower for the patients with a Brown Class 2a or smaller defect than for Brown Class 2b or larger (P = .005). CONCLUSION: Postoperative RT was the strongest variable affecting QoL in patients with maxillectomy and prosthetic obturator reconstruction. The size of the defect slightly influenced the obturator function; however, it did not influence the overall QoL.

[Effect of topical iron, fluoride application on eroded enamel in vitro].

PURPOSE: To evaluate the effect of supplementation containing iron and/or fluoride on eroded enamel in vitro. METHODS: Eighty enamel specimens collected in orthodontic treatments were randomly allocated into 4 groups of 20 samples each: C (control,deionized water); Fe(2+)(15 mmol/L FeSO(4)); F(-)(1.23% NaF) and Fe(2+)+ F(-)(15 mmol/L FeSO(4) and 1.23% NaF ). Before all samples submitted to 6 alternating demineralization and remineralization cycles, they were pre-treated with one of the experimental solutions for 1 minute. One complete cycle consisted of the following steps: ①demineralization in 5 mL beverage (Coca-Cola, pH=2.58) for 5 minutes under gentle agitation; ②remineralization in 5 mL artificial saliva for 1 hour at 37°C. The effect of erosion was observed by enamel surface morphology and measured by superficial micro-hardness (SMH). One-way ANOVA was performed using SPSS18.0 software package for analysis of the data. RESULTS: The SMH of enamel after erosion by carbonated drinks was significantly lower than the SMH before erosion. When ferrous sulfate with or without fluoride was tested for the prevention of enamel demineralization, there was statistically significant increase in the SMH of enamel in comparison with the control (P<0.001). However, the experimental solutions did not differ significantly among them. Scanning election microscope showed the deposition on the enamel surface after iron or fluorine treatment ,and the damage degree of the enamel surface were reduced compared with the control. CONCLUSIONS: Iron and/or fluoride was shown to be effective to enhance the acid resistance of enamel,while the combined use of fluoride and iron in group Fe(2+)+F(-)had no cumulative effects.

Allele and haplotype diversity of new multiplex of 19 ChrX-STR loci in Han population from Guanzhong region (China).

X-chromosomal short tandem repeats (X-STRs) have been proved to be useful for some deficiency paternity cases in recent years. Here, we studied the genetic polymorphisms of 19 X-STR loci (DXS10148-DXS10135-DXS8378, DXS10159-DXS10162-DXS10164, DXS7132-DXS10079-DXS10074-DXS10075, DXS6809-DXS6789, DXS7424-DXS101, DXS10103-HPRTB-DXS10101 and DXS7423-DXS10134) in 252 male and 222 female individuals from Guanzhong Han population, China. No deviation for all 19 loci was observed from the Hardy-Weinberg equilibrium. The polymorphism information content values of the panel of 19 loci were more than 0.5 with the exception of the locus DXS7423. The combined power of discrimination were 0.9999999999999999999994340 in females and 0.9999999999997662 in males, respectively; and the combined mean exclusion chances were 0.999999993764 in duos and 0.999999999997444 in trios, respectively. The haplotype diversities for all the seven clusters of linked loci were more than 0.9. The results showed that the panel of 19 X-STR loci were powerful for forensic applications in Guanzhong Han population. Locus by locus population comparisons showed significant differences at more than seven loci between Guanzhong Han population and the groups from North America, Europe and Africa.

[Study on enhancement effect and mechanism of the acid resistance of enamel by Fe2+ and F].

PURPOSE: The phase of new substances and the effect on enamel lattice was analysed after ferrous sulfate ,sodium fluoride treatment through X-ray diffraction, in order to explore the mechanism of Fe2+ and F- reinforced enamel acid resistance. METHODS: Fragments of enamel obtained from fifty molars were ground into powder and randomly divided into four groups: C (control,deionized water); Fe2+ (15 mmol/L FeSO4); F- (1.23% NaF) and Fe2++F- (15 mmol/L FeSO4 and 1.23% NaF). Before exposure to acid, the samples were incubated in one of the experimental solutions for 48 hours. After that, the samples were submitted to six alternating remineralization and demineralization cycles. A complete cycle consisted of the following steps:① demineralization in 5 mL of the beverage (Coca-Cola, pH=2.58) for 5 minutes under gentle agitation;② remineralization in 5 mL of artificial saliva for 1 hour at 37℃. X-ray diffraction was employed to identify precipitates and estimate their lattice constants before enamel power dried at 40℃. RESULTS: The XRD pattern of the group of ferrous sulfate was not sharper than control while the full width half maximum of peak increased and became more gentle. The enamel crystal grain size and crystallinity decreased. Secondary phase retrieval showed there was new phase formed which was iron phosphate. Diffraction spectrum of ferrous sulfate with fluoride group was similar to fluoride alone, the full width half maximum of peak became sharper and more narrow.The enamel crystal grain crystallinity improved and there was new phase of calcium fluoride formed. CONCLUSIONS: Fe2+ and F- both had certain influence on the crystal structure of enamel. However, the impact of Fe2+ was concealed when reacted with high concentration F-. Fe2+ may participate in the nucleation of apatite through substitution of calcium in apatite. Acid-resistant enamel surfaces are established due to precipitation of ferric phosphates on the enamel surface, and combination of Fe2+ with PO4(3-) dissolved on enamel surface. F- may participate in the nucleation of apatite through substitution of OH-; at the same time, the calcium fluoride precipitation was established.

[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.

Dental fluorosis in children in areas with fluoride-polluted air, high-fluoride water, and low-fluoride water as well as low-fluoride air: a study of deciduous and permanent teeth in the Shaanxi province, China.

OBJECTIVE: The aim of the study was to assess dental fluorosis (DF) in the deciduous and permanent teeth of children in areas with high-F coal (area A) and high-F water (area C) compared to children from area B, with low-F water and coal. MATERIAL AND METHODS: 596 children were examined. DF was assessed by TF-score. F-content of indoor air, drinking water, coal, tea, rice, and maize was analyzed. RESULTS: F-content of air and coal ranged from 3.2 microg/m(3) and 25.8 mg/kg (area B), 3.8 microg/m(3) and 36.3 mg/kg (area C) to 56.8 microg/m(3) and 713.1 mg/kg (area A). Likewise, mean F-content of water ranged from approximately 0.50 mg/l (areas A and B) to 3.64 mg/l (area C). F-content of tea leaves was similar in all three areas. Maize and rice contained <5 mg F/kg. Prevalence of primary teeth with DF was 49.1%, 2.0%, and 66.8% in areas A, B, and C, respectively. Similarly, DF was found in 96.7% (area A), 19.6% (area B), and 94.4% (area C) of the permanent teeth. Severe fluorosis (TF > or = 5) was found in area A (47.0%) and area C (36.1%) (p<0.01). Early erupting teeth had slightly higher mean TF-scores in area A than in area C. CONCLUSIONS: DF was prevalent in both dentitions in areas A and C. Similarity in percentages of DF may indicate that indoor air with approximately 60 microg F/m(3) and drinking water with 3.6 mg F/L are similarly toxic to developing permanent teeth. The percentage of deciduous teeth with DF was significantly lower in area A compared to area C. Where low-F coal and low-F water were used (area B), approximately 20% of permanent teeth had DF, indicating a relatively low tolerance to fluoride in Chinese children brought up under the present living conditions.