4 research outputs found
Evaluation of Er,Cr:YSGG Laser Effect on Microshear Bond Strength of a Self-Adhesive Flowable Composite in the Dentin of Permanent Molar: An In Vitro Study
Aim and Background. Recently, new restorative materials such as self-adhesive flowable composites, because of their simple use and no need to bonding and etching, are considered important, particularly in pediatric dentistry. The aim of this study is to evaluate the effect of Er,Cr:YSGG laser on microshear bond strength of self-adhesive flowable composite on permanent teeth dentin in vitro. Material and Methods. In this experimental study, 40 dentin sections were prepared from healthy third molars and divided into two groups according to their surface preparation by Er,Cr:YSGG laser or without laser, only with silicon carbide paper. In each group, two groups of 10 teeth were treated with self-adhesive flowable composite (Dyad) and conventional flowable composite (acid etch and bonding). Samples were stored in normal saline and after 48 hours their bond strength was measured. The failure mode of samples was observed on stereomicroscope. In order to analyse the results, the one way ANOVA and Tukey’s test for multiple comparisons were used. Result. The maximum bond strength was related to conventional flowable composite with laser preparation group (24/21 Mpa). The lowest one was seen in Dyad composite without laser emitting (9/89 Mpa). The statistical difference between this two groups was significant (P value = 0/0038). The microshear bond strength differences between Dyad composite groups with laser preparation (mean = 16/427±1/79) and without laser preparation (mean = 12/85±1/90) were statistically significant too (P value = 0/01). Conclusion. Self-adhesive flowable composite has lower microshear bond strength than conventional flowable composite. Moreover, the laser irradiation as a surface treatment can improve this bond strength
Fluoride Concentration of Bottled Water and Tap Water in Tehran, Iran
Background and aims. As a result of poor quality of public water supply in many countries, people have recently
turned to bottled water consumption, the fluoride content of which is not generally consistent among different brands. This
study sought to measure the fluoride concentration of public water supply in comparison with commercial brands of mineral
bottled water available in Tehran, Iran.
Materials and methods. Eight different brands of locally produced bottled mineral water and samples of tap water
were evaluated for fluoride content. All samples were collected in five equal containers in two summer and winter seasons.
The fluoride content in part per million (ppm) was determined using a fluoride Ion Selective Electrode. The data were analyzed
using two-way ANOVA. For comparison of the fluoride content between three different brands of bottled water, oneway
ANOVA was employed. Sample t-test was used to compare the label and laboratory values of bottled water.
Results. The highest concentration of fluoride in a bottled water brand was found to be 0.409 ppm with a pH of 6.67 in
summer. There was a significant difference between the mean fluoride level of tap water (0.229 ± 0.079 ppm) and bottled
water (0.111 ± 0.122 ppm) (P < 0.001). The measured fluoride concentrations of bottled water were significantly lower
than those printed on the labels (P < 0.001).
Conclusion. Our findings revealed that the mean fluoride level of both bottled and tap water samples evaluated is considerably
lower than accepted standards
Relationship of Salivary Lactoferrin and Lysozyme Concentrations with Early Childhood Caries
Background and aims. Lysozyme and lactoferrin are salivary proteins which play an important role in innate defense mechanisms against bacteria. This study investigated the association of salivary lysozyme and lactoferrin concentrations with early childhood caries (ECC).
Materials and methods. This study was carried out on 42 healthy children (age range, 36 to 71 months), of whom 21 were caries free (CF) and 21 had ECC. Disposable needle-less syringes were used to collect unstimulated saliva from buccal and labial vestibules. Fifteen children who had ECC were treated completely and their saliva was collected in the same way for the second time, three months after treatment. Lysozyme and lactoferrin concentrations were measured and recorded by the ELISA method. The intergroup comparisons were carried out using chi-square, Student’s t-test and Wilcoxon signed ranked test. A P-value less than 0.05 was considered as statistically significant.
Results. The mean concentration of lysozyme was significantly higher in CF group compared with that of ECC group (P = 0.04). Although the mean concentration of lactoferrin in ECC group was higher in comparison with ECC group, the differ-ence was not statistically significant (P = 0.06). After dental treatment, the mean concentrations of lysozyme and lactoferrin did not change in comparison with their concentrations before treatment.
Conclusion. ECC may have a relationship with lower concentrations of unstimulated salivary lactoferrin and lysozyme and reduced amounts of these two salivary proteins may be a risk factor for dental caries in children