Effect of heat sterilization and chemical method of sterilization on the polyvinyl siloxane impression material. A comparative study.

BACKGROUND: Dental impression is a crucial part of the process of constructing a well-fitting prosthesis. In the clinical scenario, impressions can act as a vehicle for the transfer of bacteria and fungi. Therefore, an attempt was made to evaluate the dimensional accuracy of the newly introduced polyvinyl siloxane (PVS) impression material upon autoclaving and comparing it to the traditional means of chemical disinfection. MATERIALS AND METHODS: A cross-sectional comparative in vitro study was conducted. Three groups were made for testing different sterilization methods. The sample size for the study was kept as 30 observations in each of the three groups. Test samples were prepared by making an impression of the die using the putty-wash technique. Statistical analysis was done by applying unpaired t-test, paired t-test, one-way analysis of variance (ANOVA) and post hoc Tukey's honestly significant difference (HSD). RESULTS: Initial mean of samples of group I were compared to A (actual measurement of metal ruled block = 24.960), a dimensional change of 1.6% was found. Similarly, in group II, a change of 1.59% was found and in group III the change was 1.7%. There was mean shrinkage of 24.557 mm in group I, 24.586 mm in group II, and 24.535 mm in group III and these changes were found statistically significant. CONCLUSION: Dimensional changes in the impression material after disinfection with 2% glutaraldehyde were considered high compared to autoclaving and, hence, it may not be advisable to disinfect this material with 2% glutaraldehyde.

Influence of Implant Neck Design on Crestal Bone Loss: A Comparative Study.

BACKGROUND: The success rate of dental implants depends on the amount of crestal bone around the implants. Crestal module is the transosteal region of implant that is designed to receive the prosthetic component. The design of crestal module influences the crestal bone loss around implants. AIM: The purpose of this study was to evaluate and compare the crestal bone loss around implants with smooth collar and implants with micro threaded rough collar design. MATERIALS AND METHODS: A total of 150 individuals received 100 dental implants. Each individual received one implant with smooth collar design (Group-A) and one implant with microthreaded rough collar design (Group-B) in the posterior edentulous region. All the 100 implants were prosthetically loaded after a healing period of 3 months. Crestal bone loss was measured on mesial, distal, buccal, and lingual side of each implant using periapical radiographs before loading (baseline), immediately after loading, 6, and 12 months after loading. RESULTS: The average crestal bone loss 12 months after loading the implants in Group A and Group B was 3.75 mm and 3.23 mm, respectively, the value being statistically significant (P < 0.05). In both Group A and Group B, the average crestal bone loss was maximum on the lingual side followed by buccal, distal, and mesial sides. CONCLUSION: Crestal bone loss around rough-surfaced microthreaded neck implants was significantly lower than smooth-surfaced neck implants.

Red complex: Polymicrobial conglomerate in oral flora: A review.

Oral diseases are the complex host responses composed of a broad array of inflammatory cells, and cytokines, chemokines, and mediators derived from the cells resident in the gingival tissues, as well as from the emigrating inflammatory cells. A chronic polymicrobial challenge to the local host tissues triggers this response, which under certain circumstances, and in a subset of the population, leads to the progressing soft and hard tissue destruction that characterizes periodontitis. The red complex has been proposed as a pathogenic consortium, consisting of P. gingivalis, T. denticola, and T. forsythia. This review has attempted to examine the virulence potential and determinants of these commensal opportunists.

Calciphylaxis and its diagnosis: A review.

Calciphylaxis also known as Calcific uremic arteriolopathy (CUA), is a rare fatal complication usually associated with end-stage renal disease (ESRD). It is characterized by skin ulceration and necrosis leading to significant pain. The disease calciphylaxis is pathological state resulting in accumulation of calcium content in medial wall of small blood vessels along with the fibrotic changes in intima. The aetiopathogenesis of this disease, small vessel vasculopathy, remains complicated, and unclear. It is believed that development of calciphylaxis depends on medial calcification, intimal fibrosis of arterioles and thrombotic occlusion. The disease is rare, life-threatening medical condition that occurs mostly in population with kidney disease or in patients on dialysis. Skin biopsy and radiographic features are helpful in the diagnosis of calciphylaxis, but negative results do not necessarily exclude the diagnosis. This article highlights steps undertaking in the diagnosis of calciphylaxis.

In vitro Evaluation of the Accuracy of Seating Cast Metal Fixed Partial Denture on the Abutment Teeth with Varying Degree of Convergence Angle.

BACKGROUND: The prime goal of a diligent prosthodontist is to obtain adequate marginal fit while restoring lost tooth structure. The marginal fit of the restoration, in turn depends upon the geometrical morphology of the tooth preparation. OBJECTIVE: To determine the effect of varying degree of convergence angle on the marginal seating of the single crown, three-unit fixed partial denture and multiple-unit fixed partial denture with pier abutment. MATERIALS AND METHODS: Three dies, of same convergence angle, were placed in an arch form on a base. In this way, four arch forms were prepared for four different convergence angles i.e. 0°, 6°, 12°, and 20°. Five castings each were made for single crown, 3-unit fixed partial denture and multiple-unit fixed partial denture (FPD) with pier abutment for each convergence angle. The castings were seated on their respective dies and vertical marginal discrepancy was measured at four points for each casting with the help of an optical microscope. RESULTS: The results showed that 200 convergence angle showed better marginal seating of the single crown, 3-unit FPD as well as for the multiple unit FPD. CONCLUSION: There was a possibility that the retention and resistance may be compromised with 200 taper. Hence 120 taper is suggested for crowns and fixed partial denture retainers as the marginal discrepancy is reasonable and retention and resistance is optimum. There was a high statistical significant difference in the values obtained for the different convergence angles.