Biocompatibility or tissue compatibility describes the ability of a material to perform with an appropriate host response when applied as intended. Poly-methylmethacrylate (PMMA) based resins are most widely used resins in dentistry, especially in fabrication of dentures and orthodontic appliances. They are considered cytotoxic on account of leaching of various potential toxic substances, most common being residual monomer. Various in vitro and in vivo experiments and cell based studies conducted on acrylic based resins or their leached components have shown them to have cytotoxic effects. They can cause mucosal irritation and tissue sensitization. These studies are not only important to evaluate the long term clinical effect of these materials, but also help in further development of alternate resins. This article reviews information from scientific full articles, reviews, or abstracts published in dental literature, associated with biocompatibility of PMMA resins and it is leached out components. Published materials were searched in dental literature using general and specialist databases, like the PubMED database.
Background:Teeth when subjected to bleaching bring about the desiccation of the enamel, making it more susceptible to stain absorption. While subjecting the freshly bleached enamel surface to various surface treatments of Fluoride and Casein Phosphopeptide - Amorphous Calcium phosphate (CPP-ACP) brought about the reduction in stain absorption, which is assessed in this study.Aims:The study aims to evaluate the tea stain absorption on freshly bleached enamel surface of extracted human teeth with varied surface treatment. The stain absorption was evaluated at the end of one hour and 24 hours post bleaching.Materials and Methods:Forty extracted human permanent maxillary central incisors were subjected to bleaching with 10% carbamide peroxide for eight days. They were divided into four groups of 10 each. Group I was control group. Group II was immersed in tea solution without surface treatment, while Group III and IV were immersed in tea solution with surface treatment of topical Fluoride and CPP-ACP respectively. Spectrophotometer was used for color analysis.Results:Surface treatment with CPP-ACP and topical fluoride on freshly beached enamel surface, significantly reduced the stain absorption.Conclusion:Remineralizing agents reduce stain absorption after tooth bleaching.
The effect of osteoporosis on residual ridge resorption and masticatory performance in denture wearers Aim: To compare masticatory performance, masticatory efficiency and residual ridge resorption (RRR) in osteoporotic and non-osteoporotic edentulous subjects after rehabilitation with complete dentures. Method: Thirty subjects fulfilling the inclusion criteria were enrolled from the patients visiting the Department of Prosthodontics for complete denture fabrication. Two groups consisting of control subjects (group I; N = 15) and osteoporotic subjects (group II; N = 15) were formed. Complete dentures satisfying certain criteria were fabricated for both groups. Masticatory performance and efficiency were measured 6 months after denture insertion. Areal measurements were taken on lateral cephalograms before and 6 months after denture fabrication. The data were then computed to analyse differences between groups I and II using SPSS statistical software version 15.0. Results: Six months after denture fabrication, the masticatory performance and efficiency were significantly higher (p < 0.001) for group I, with a significant decrease in maxillary and mandibular sagittal area seen in both groups. The rate of bone loss was more in group II compared with group I. Conclusion: Greater masticatory function was demonstrated by the non-osteoporotic group, and the rate of RRR was more in the osteoporotic group compared with the normal group. In this pilot study, osteoporosis leads to greater RRR, decreased masticatory performance and efficiency in edentulous subjects 6 months after denture insertion. Screening for osteoporosis is suggested as a routine procedure for all edentulous subjects undergoing rehabilitation. Recall check-ups for osteoporotic patients should be more frequent, and these patients may require more frequent denture remakes.
The loss of tooth in the esthetic area is often a traumatic experience for the patient. Patients may suffer real or perceived detrimental effects following the loss of one or more teeth. Dental implant offers the most cost-effective and long-term solution for replacement of missing teeth with high average life expectancy, providing the patient with the best sense of security and well-being. Recently, immediate implant placement after extraction of tooth with early loading has become more common. The advantages of this procedure include fewer surgical interventions, reduction in overall treatment time, reduced soft and hard tissue loss, and psychological satisfaction to the patient. This case report describes the procedure for immediate implant placement with immediate loading of implants by provisional restorations.
Forty nine genotypes of wheat were studied for generating scientific information on nature and magnitude of genetic variability and diversity for designing breeding programme. The experiment was conducted in randomized complete block design in three replications. The data were recorded on days to 50% flowering, plant height, peduncle length, number of productive tillers per plant, days to maturity, spike length, number of spikelets per spike, number of grains per spike, 1000-grain weight, biological yield per plant, grain yield per plant, harvest index and gluten content. Analysis of variance revealed significant differences among the genotypes for all the characters under study. The highest estimates of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for grain yield per plant. High heritability coupled with high genetic advance was observed for grain yield per plant. Based on D 2 -Statistics, 49 genotypes were grouped into eight clusters. The highest inter-cluster distance was found between cluster VII and VIII followed by III and VII. This indicates that genotypes included in these clusters possess wide genetic diversity. Grain yield per plant (31.46%) showed highest contribution towards genetic divergence; therefore, this character was major determinant of genetic diversity. On the basis of divergence and cluster mean it may be suggested that maximum heterosis and good recombinants could be obtained in crosses between genotypes of cluster VIII, VII and III in varietal improvement programme. Thus, crosses between the genetically diverse genotypes of cluster VIII with genotypes HUW 655, HP 1937, DBW 88 and HD 3058 and cluster VII with genotypes like HP 1938, HUW 656, K1006, DBW83, DBW 84, K1004, UP2822 and NW5050 are expected to exhibit high heterosis and are also likely to produce new recombinants with desired traits.
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