ABSTRACT
The purpose of this in vitro study was to analyse the absorbance of dye material in conventional glass ionomer cement [GIC] by applying various commercially available surface protecting layers on GIC. 90 disc-shaped specimens were made using brass mold measuring 7mm in diameter and 2mm in thickness. 30 specimens were selected for each week testing having 6 groups [n=5]. The groups were: G1 [Control group], G2 [Nail polish coated GIC], G3 [Master bond coated GIC], G4 [Copal varnish coated GIC], G5 [Varnal coated GIC], G6 [Cold mold seal coated GIC]. The specimens of each group were immersed in a separate test tube filled with methylene blue dye, and placed in an incubator [37[degree]C +/- 2[degree]C] for 1 week, 2 weeks and 3 weeks' time. After required time period, the specimens were rinsed under distal water for 1 minute and air dried for 1 hour. Next, the specimens of each group were put into new test tubes containing 1ml absolute alcohol and again stored at [37[degree]C +/- 2[degree]C] for 24 hours. Absorbance were recorded in ultraviolet spectrophotometer. Results were analysed by Student t-test and Pearson's correlation. The results suggest that varnal and copal varnish are effective protecting materials with significant difference [P<0.01] after 3 weeks time. Our results conclude that the application of suitable protecting material may lead to longevity of GIC restorative biomaterial in a complexed oral environment
ABSTRACT
Objective: The aim of this research was to assess the effect of mouth rinses with and without alcohol on the hardness of dental nano-filled composite
Methods: The micro-hardness of fifty circular disk shaped specimens of 7 mm x 2 mm were measured after 14 days. Specimens were immersed into alcohol containing [Listerine and Colgate Perioguard] and alcohol-free [Prodent and Sensodyne Oral antiseptic] mouth rinse solutions. Artificial saliva served as the control. Vickers Micro-hardness was measured with a 30gram load for 30 seconds dwell time by using a diamond indenter. Significant differences were represented by p<0.05, whereas highly significant difference represented by p<0.01. The level of significance [p] was calculated with the help of repeated measure ANOVA. For multiple comparisons, Tukey's multiple comparison test was used
Results: Statistical analysis revealed highly significant difference between specimens immersed in artificial saliva [control] and Listerine [p<0.01]. Whereas significant difference were observed between control and Colgate Periogard [p<0.05]. However, no significant difference was observed on comparing Prodent and Sensodyne Oral antiseptic mouth rinses with control group[p>0.05]. Control specimens depicted highest value of micro-hardness[60.5746 +/- 3.2703] compared to the lowest value seen in specimens immersed in Listerine solvent[54.4687 +/- 1.0937]
Conclusion: Alcohol containing mouth rinsing solutions have more deleterious effect on hardness of nano composites as compared to alcohol-free mouth rinses
Subject(s)
Acrylic Resins , Polyurethanes , Dental Materials , Mouthwashes , Hardness , MicroscopyABSTRACT
Erosion of tooth surface is attributed to recent shift in diet pattern and frequent use of beverages. The aim of this research was to evaluate the effects of different beverages on surface topography and hardness of nano-filled composite material. Sixty flat disc shaped resin composite samples were fabricated and placed in distilled water for 24 hours. After 24 hours test samples were dried and divided into 4 groups. Group A [n=15] specimens were placed in tight amber bottle comprising 25 ml of artificial saliva. Similarly Group B, C and D were stored in equal amounts of orange juice, milk and coca cola drink respectively. Samples were checked for hardness and surface changes were evaluated with scanning electron microscopy. There were strong significant difference observed in samples immersed in orange juice and artificial saliva. A strong significant difference was seen between Group D and Group A. Group A and Group C showed no significant difference. The micro-hardness test showed reduced values among all samples. Beverages consumed daily have a negative influence on hardness and surface degradation of nano-filled dental composite. Comparatively, nano-filled composites possess higher surface area to volume ratio of their fillers particle size may lead to higher surface roughness than other resin based dental biomaterials
ABSTRACT
Dental professional and their supporting staff daily handle many materials and chemicals with their uncovered hands. One of the most widely used chemical is methyl methacrylate monomer based dental material. Materials based on methacrylate and its polymer appear to be a significant reason for contact dermatitis in dental personnel. There may be other unfavourable effects on health. Objectives of the study was to see the effect of uncured polymeric resin composite material on the health of dental personnel. This survey based cross-sectional study was done on 330 dentists working in different areas of Karachi. Data were collected by interviews, telephonic conversations or by mailing questionnaire to the participants. The sampling area was the Karachi city and sampling method was non-random convenience sampling. The data were analyzed using SPSS version 17. Results showed that methyl methacrylate based resin composite material is a source of various allergic reactions among the dental personnel. It was concluded that the material can have adverse effects on dental practitioners and patients
ABSTRACT
To determine the sorption rate of flowable dental composites by using different photo-activation techniques. Ninety specimens of 3 different dental composites were used for study. 7mm in diameter and 2mm thick disc of each material were prepared in the laboratory by using brass moulds. 30 samples were polymerized each by Quartz Tungsten Halogen [QTH], Light Emitting Diode [LED] and Ultraviolet B [UVB] light curing units. Samples were taken out from mould and placed in clean glass tube, immersed in 2% methylene blue solution and placed in incubator for 24hrs. Absorbance was detected at 590nm by using Visible Spectrophotometer. The significant results were observed by using both Light Emitting Diode and Quartz Tungsten Halogen light units [*P< 0.01]. Ultraviolet B narrowband light found to be inappropriate for polymerization purpose. Similarly, composite Clinpro and Bioseal showed significant results in every photo-activation method [*P<0.01]. Light Emitting Diode units were as efficient in curing resin composite as Conventional Halogen lamps are. Ultraviolet B narrowband light was not appropriate in activation of dental composite while Clinpro and Bioseal are efficient flowable composites
Subject(s)
Ultraviolet Rays , Methylene Blue , Spectrum Analysis , SpectrophotometryABSTRACT
Techniques for bonding denture teeth to acrylic resin denture base remains empirical, with little consensus from the literature, among clinicians or among dental laboratories. Despite of this great variation, the data available regarding effectiveness of various methods used are sparse. The study was carried out to compare the effect of different surface treatments of ridge lap area of acrylic resin denture teeth on bond strength of acrylic resin denture teeth with acrylic resin denture base. 180 Maxillary central incisors were divided into 6 groups of 30 each according to surface preparations. First group served as the control with no surface preparation; other groups included horizontal grooves, vertical grooves, diatorics, sand blasting and roughened surfaces. Compressive shear force was applied to incisal edge of each tooth until fracture occurred, the force recorded and teeth visually inspected to determine adhesive or cohesive failure. Significant increase in failure load ranged for diatoric 274 +/- 78N. Significant decrease in failure mode was observed after sand blasting 157 +/- 79N. Remaining groups showed non-significant increase in force required for bond failure