Raghuwar Dayal Singh

Biocompatibility of polymethylmethacrylate resins used in dentistry

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.

Efficacy of casein phosphopeptide-amorphous calcium phosphate to prevent stain absorption on freshly bleached enamel: An in vitro study

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.

Genes and oral cancer

Oral cancers have been one of the leading causes of deaths particularly in the developing countries. Prime reason for this high mortality and morbidity is attributed to the delay in diagnosis and prompt treatment. Relentless research in the field of oncology has led to the advent of novel procedures for the early detection of oral cancers. Molecular biology is highly promising in this regard. It is a procedure that detects alterations at a molecular level much before they are seen under a microscope and much before clinical changes occur. Molecular studies serve as the basis by which we will eventually be able not only to augment clinical assessment and classification of oral lesions but also predict malignant potential of oral lesions, thus reducing the incidence and increasing the scope for early diagnosis and treatment of oral cancers. However, making such sophisticated tools available for the common man in developing countries is one of the most important challenges faced today.

Prosthodontic Rehabilitation in Sjogren's Syndrome with a Simplified Palatal Reservoir: Two Year Follow Up

PATIENTS A 45-year-old female patient came to the institute complaining of reduced salivation, pain and food lodgment in multiple teeth, and difficulty in eating. The systemic examination revealed dry eyes, dry mouth, cracking of corners of mouth and lack of appetite. The diagnostic tests were conclusive of Sjogrens syndrome, which is associated with xerostomia, ocular dryness and connective tissue disorders. Major oral problems in such patients include high caries rate, burning of oral mucosa, early tooth loss, increased tooth wear, poor tolerance for dentures and repeated failure of dental restorations. DISCUSSION Prosthodontic therapy for this unique patient group is challenging and neglected, due to limited choice of abutments, loss of vertical dimension and poor occlusion. Two-year follow up of a patient of Sjogrens syndrome who was rehabilitated by a combination of fixed and removable prostheses, with a simplified palatal salivary reservoir is presented. CONCLUSION Though the patient felt an improvement in quality of life due to the prosthesis, slurred speech and frequent reservoir refilling remained problems.

High Performance Liquid Chromatographic Determination of Residual Monomer Released from Heat‐Cured Acrylic Resin. An In Vivo Study

PURPOSE Heat-polymerized acrylic resins are used in dentistry for complete denture fabrication. Despite the polymerization method, conversion of monomer into polymer is often incomplete with free or unreacted residual monomer remaining in the polymerized resin. The aim of this study was to determine the amount of residual monomeric methyl methacrylate (MMA) leaching in the saliva of patients wearing complete dentures in their postinsertion period. MATERIALS AND METHODS Thirty edentulous participants as first-time complete denture wearers (age 60 to 65 years) were selected. All the prostheses were fabricated using a similar standard technique with a heat-cured acrylic resin denture base material. Saliva samples were collected at time intervals of 1 hour, 1 day, and 3 days postdenture insertion. Participants were asked to discharge saliva every 30 seconds into a pre-weighed screw-capped container for a 5-minute period. MMA levels were measured using high performance liquid chromatography. Data were analyzed by ANOVA and Tukey-HSD. RESULTS The maximum concentration of monomer released into saliva peaked 1 day after insertion of the complete dentures. The mean (SD) MMA content was 0.04 ± 0.01 (μg/ml) 1 hour after insertion, and 0.3 ± 0.09 (μg/ml), and 0.05 ± 0.01 (μg/ml) on the first and third days postinsertion, respectively. CONCLUSIONS Although the released monomeric MMA was not at toxic levels, it could potentially sensitize complete denture patients or elicit an allergic reaction. The risk of the residual material as a primary irritant for a sensitizing reaction could be minimized by immersion of the denture in water for 24 hours before insertion.

Evaluation of various treatment modalities in sleep bruxism

STATEMENT OF PROBLEM Sleep bruxism (SB) is an oral condition that is associated with tooth wear, orofacial pain, and interference with sleep. The most recommended management technique is the use of an occlusal splint. Although the mandibular advancement device (MAD) has shown good results, few well-designed randomized controlled trials are available with which to compare these treatment options. Therefore, an evaluation of the effect of these 2 appliances on SB is needed. PURPOSE The purpose of this study was to evaluate the effect of a MAD and a maxillary occlusal splint (MOS) on the sleep quality and SB activity of participants with SB. MATERIAL AND METHODS In this randomized controlled trial, 28 participants were randomly supplied with either a MAD or MOS. The sleep quality of the participants was evaluated with the Pittsburgh Sleep Quality Index (PSQI) and their SB activity with electromyographic activity of the masseter with polysomnography. These variables were measured at baseline, 1 month, and 3 months. RESULTS Of 32 participants, 28 had data available for statistical analysis, as 4 participants did not return for follow-up examination. Both the MOS and MAD significantly reduced the PSQI and SB episodes and bursts in participants after 3 months (P<.05). The MAD provided greater reduction in SB episodes per hour after 3 months compared to the MOS. Participants supplied with a MAD reported more discomfort in their feedback form than participants using a MOS. CONCLUSIONS Both the MAD and MOS provided significantly improved sleep quality and a decrease in SB episodes at 3 months.

Lost salt technique for severely resorbed alveolar ridges: An innovative approach

The success of a complete denture relies on the principles of retention, stability and support. The prosthodontist skill lies in applying these principles efficiently in critical situations. Severely resorbed maxillary edentulous ridges that are narrow and constricted with increased inter ridge space provide decreased support, retention and stability. The consequent weight of the processed denture only compromises them further. This article describes a case report of an edentulous patient with resorbed ridges where a simplified technique of fabricating a hollow maxillary complete denture using lost salt technique was used for preservation of denture bearing areas. The hollowing of the denture reduces the weight of the denture, thereby enhancing stability and retention, reducing the further resorption of the jaws.

Three-dimensional Quantitative Analysis of the Bone Density of Mandibular Condyle in Dentulous and Edentulous Jaws: An In Vivo Study

Studies have reported that masticatory function and occlusal force are low in edentulous patients, which brings about a change in the density, thickness, and alignment of bony trabeculae. However, studies that have quantitatively measured the differential cortical and medullary bone densities of the mandibular condyle in vivo remain rare. This study determined and compared the cortical and medullary bone density of the mandibular condyle in dentulous and edentulous jaws, using multidetector computed tomography (CT). Forty mandibular condyles with no clinical signs of temporomandibular disorders were investigated in 2 groups with 10 subjects (aged 50-80 yr) in each group (group I: dentulous subjects with maintained occlusion; group II: completely edentulous patients) with multidetector CT. The density of condylar cortical and medullary bone was determined by using bone density analysis algorithms available within the proprietary software. Data were analyzed statistically with the 1-way analysis of variance test (p<0.05). The mean cortical bone density of the right and left condyles of group I was 686.11±102.78 Hounsfield unit (HU) and 775.91±89.62 HU, respectively and that of group II was 531.33±289.73 HU and 648.53±294.39 HU, respectively. The mean medullary bone density of the right and left condyles was maximum in group I subjects (429.69±102.62 HU and 486.62±108.60 HU, respectively) than in group II subjects (214.89±104.37 HU and 205.36±90.91 HU, respectively) with a statistically significant decrease in the mean scores (p<0.001). Within the limitations of this study, it can be concluded that the cortical and medullary densities of the mandibular condyle are more in dentulous than the edentulous jaws.

A Simplified Method to Fabricate a Pneumatic Ocular Prosthesis for Large Ocular Defects.

When an enucleation or exenteration procedure removes the entire orbital contents but not the eyelids, an abnormally large orbital socket is created that would require an equally sized volume enhancing, flush fitting ocular prosthesis. The solid acrylic prosthesis would rest on or in the lower fornix and owing to its weight, causes distortion of the lower eyelid and/or asymmetrical alignment of the entire palpebral fissure. The aim of this article was to describe a method of fabricating a pneumatic light weight custom ocular prosthesis using lost wax technique to overcome the deteriorating effects of conventional solid ocular prosthesis.

Measuring implant stability: A review of different methods

Achieving and maintaining implant stability are prerequisites for a dental implant to be successful. Implant stability can be defined as the absence of clinical mobility, which is also the suggested definition of osseointegration. Primary implant stability at placement is a mechanical phenomenon that is related to the local bone quality and quantity, the type of implant and placement technique used. Secondary implant stability is the increase instability attributable to bone formation and remodeling at the implant/tissue interface and in the surrounding bone. There are many ways in which the implant stability can be evaluated such as clinical measurement of cutting resistance during implant placement, reverse torque test, the periotest. This article aims to throw light on the various methods to determine implant stability.