Microleakage and Marginal Integrity of Surface-Coated and Laser-Pretreated Class V Composite Restorations in Primary Teeth.

Introduction: Despite the advanced formulations of resin composites, microleakage is still among the commonest causes of clinical failure of these restorations. We evaluated the effect of surface coating and laser pretreatment on the microleakage of Class V resin composite restorations in primary teeth. Methods: Sixty extracted primary molar teeth having intact lingual or facial surfaces were randomly allocated into the control, G-Coat Plus surface coating, and erbium-doped yttrium aluminum garnet (Er:YAG) laser pretreatment groups. Class V cavities were provided with the coronal and gingival margins in the dentin and enamel, respectively. Restoration of the cavities was done with Z250 resin composite and they were thermocycled, followed by immersing in 2% basic Fuchsin dye for 24 hrs. Samples underwent sectioning occlusogingivally and the microleakage was assessed under a stereomicroscope (40×). Statistical analysis was done via SPSS and Kruskal-Wallis test (α=0.05). Results: The control and G-Coat plus groups were significantly different regarding the microleakage (P<0.001), and G-Coat Plus and laser pretreatment groups (P<0.001) at both gingival and occlusal margins. However, it showed no significant difference between the laser and the control group on the enamel (P=0.063) and dentin margins (P=0.757). Microleakage at the gingival margins was significantly greater compared to the occlusal margins in the control and laser groups (P<0.001), but not in the G-Coat Plus group (P=0.051). Conclusion: G-Coat plus coating significantly reduced microleakage at dentin and enamel margins of Class V composite restorations in primary teeth, in comparison with other groups of the study. Also, dentin margins showed more significant amounts of microleakage versus enamel margins in all groups, except for the G-Coat Plus group.

Relationship between Salivary Alpha-Amylase Enzyme Activity, Anthropometric Indices, Dietary Habits, and Early Childhood Dental Caries.

Objectives: Although early childhood dental caries (ECC) have the same general etiology as other types of caries, predisposing factors are not well elucidated. This study aimed to investigate the effect of salivary alpha-amylase (sAA) activity, body mass index (BMI), dietary habits, and oral hygiene on ECC. Methods: This cross-sectional study was performed on 38 ECC-affected and 41 caries-free children, aged 36 to 72 months. Upon the parents' consent, 3 mL of non-stimulated saliva was collected from the participants to measure the level of sAA activity through spectrophotometry. Additionally, parents/caretakers completed a structured questionnaire about demographic factors, oral hygiene, and consumption of sugar-containing foods. BMI, BMI z-scores, and percentile data were calculated by using an online calculator. The independent variables were dichotomized and tested through chi-square test, followed by a stepwise logistic regression, by using SPSS software (α = 0.05). Results: The sAA activity was significantly higher in caries-free children (P ≤ 0.001). However, the mean BMI was not significantly different between the two groups (P=0.49). Brushing and other measured dietary habits were significantly associated with the development of ECC (P ≤ 0.001). According to the results of the logistic regression, sAA activity was shown to be a predictor for ECC development (Odds ratio (95% confidence interval): 0.9 (0.95-0.98)). Conclusion: Children with inherently lower levels of sAA activity were more susceptible to dental caries. Improper nutritional habits and poor oral health care could exacerbate the risk of ECC.

Effect of Adding Nano Size Silica on Setting Time and Porosity of Mineral Trioxide Aggregate.

Introduction: The aim of this study was to evaluate the effect of addition of nano-silica (SiO2) to mineral trioxide aggregate (MTA) on its setting time and porosity. Methods and Materials: The concentration 8% of nano-silica were prepared and added to the MTA powder. After mixing with water the setting time and porosity were evaluated and compared with pure MTA. Statistical analysis was performed using the t-test. The level of significance was set at 0.001. Results: The mean setting time of MTA+8% nano-silica (9.8±0.78) was significantly lower than MTA (23.3±2.16) ( P<0.001). Also the mean porosity by imbibition method in MTA+8% nano-silica (23.49±0.48) was significantly higher than MTA (15.69±2.10) (P<0.001). There was no significant difference in mean porosity by scanning electron microscope (SEM) method in MTA+8% nano-silica (31.26±10.73) and MTA (32.74±5.26) (P>0.001). Conclusion: This in vitro study showed us an addition of 8% of nano-silica to MTA reduced the setting time. Although evaluation by imbibition test showed increasing of porosity in nano-silica MTA compared with pure MTA.

IL-17 gene polymorphism is associated with chronic periodontitis and peri-implantitis in Iranian patients: a cross-sectional study.

Periodontal disease (PD) and peri-implantitis (PI) are characterized by an immune response leading to destructive inflammation. The prominent impact of genetic factors on periodontitis has been previously evaluated and IL-17 has found to play a critical role in this process. This cytokine has a controversial behavior. This study aimed at finding out whether the polymorphism of this cytokine plays a significant role in chronic periodontitis (CP) and PI or it is just a pro-inflammatory regulatory cytokine. Fresh human blood samples were obtained and three main genotypes were traced carefully. The samples were transferred into 96-well plates and sent to KBioscience Institute in the United Kingdom for genotyping the polymorphism using Competitive Allele Specific PCR (KASP) technique. SPSS version19 software and chi-square and Kruskal-Wallis tests were used for statistical differences considering p-value less than 0.05. A significant difference was detected between the three groups in terms of specific SNP studied in this experiment (P = 0.00). The CC genotype of IL17 polymorphism (rs10484879) may contribute to the pathogenesis of peri-implantitis and periodontitis. The association of IL-17 polymorphism with PI and CP is a promising finding that may help in future similar studies on other ethnicities and larger study populations.