Light polymerizable tooth colored restorative materials are most widely preferred for advantages such as esthetics, improved physical properties and operator's control over the working time. Since the introduction of these light polymerizable restorative materials, there has been a concern about the depth of appropriate cure throughout the restoration. Photopolymerization of the composite is of fundamental importance because adequate polymerization is a crucial factor for optimization of the physical and mechanical properties and clinical results of the composite material. Inadequate polymerization results in greater deterioration at the margins of the restoration, decreased bond strength between the tooth and the restoration, greater cytotoxicity, and reduced hardness. Therefore, the dentist must use a light curing unit that delivers adequate and sufficient energy to optimize composite polymerization. Varying light intensity affects the degree of conversion of monomer to polymer and depth of cure.
Aim:The purpose of this study is to examine the intensity of light curing units and factors affecting it in dental offices.Materials and Methods:The output intensity of 200 light curing units in dental offices across Maharashtra were examined. The collection of related information (thenumber of months of use of curing unit, the approximate number of times used in a day, and presence or absence of composite build-ups) and measurement of the intensity was performed by two operators. L.E.D Radiometer (Kerr) was used for measuring the output intensity. The average output intensity was divided into three categories (<200 mW/cm2, 200-400 mW/ cm2and >400 mW/cm2).Results:Among the 200 curing units examined, 81 were LED units and 119 were QTH units. Only 10% LED machines and 2% QTH curing units had good intensities (>400 mW/cm 2).Conclusion:Most of the examined curing lights had low output intensity ranging from 200 to 400 mW/cm2, and most of the curing units had composite build-ups on them.
Aim
To compare the effects of various levels of acidic pH on surface microhardness of Biodentine.TM
Materials and methods
Biodentine was mixed and packed into stainless steel molds (diameter = 5 mm and height = 1.5 mm). Four groups of 10 specimens each were formed and exposed to pH: 7.4, 6.4, 5.4 and 4.4 respectively for 4 days. Vickers microhardness was measured for each of the specimens and was measured 4 days after the exposure.
Results
Data was subjected to one-way ANOVA using Tukey's post hoc test. Group I (control pH = 7.4) showed greatest surface microhardness of 67.5 ± 4.1 HV. The least microhardness of 46.3 ± 5.0 HV was observed for group IV where the specimens were soaked at pH 4.4. A p-value less than 0.05 was considered to be statistically significant.
Conclusion
Under the limitations of the present study, surface hardness of Biodentine was impaired in the presence of acidic environment.
How to cite this article
Poplai G, Jadhav SK, Hegde V. Effect of Acidic Environment on the Surface Microhardness of Biodentine„§ƒ| World J Dent 2013;4(2):100-102.
Salivary secretory immunoglobulin A (sIgA) is postulated to protect against dental caries. Dental hygiene and health are usually poor in rheumatoid arthritis (RA) due to several factors. We hypothesized higher salivary sIgA in caries-free subjects and a higher extent of caries in RA. A protocol-driven cross-sectional pilot study was carried out to determine salivary sIgA in 48 patients with RA and 102 non-RA, healthy case controls. Standard of care in clinical and dental assessments were done by experts. A decay, missing teeth, filled teeth (DMFT) index was used to classify caries. Whole unstimulated saliva was collected to assay sIgA using a commercial ELISA kit. Dental caries was diagnosed in 67% and 86% of the RA and healthy subjects, respectively. Eight percent of RA patients had visited a dental surgeon. Though they tend to be higher in caries-free status, there were no statistically significant differences (p > 0.05) between RA and non-RA subjects with respect to salivary sIgA and extent of caries. The salivary sIgA levels for both RA and healthy case control subjects in this ethnic Indian (Asian) study were much higher than that reported in literature and need further validation. Rheumatologists ought to educate patients on dental matters.
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