Evaluation of esthetics of incisor position in relation to incisive papilla to replicate in the denture prosthesis.

BACKGROUND: The distance between the central incisor to incisive papilla (CI-IP) is constant and regarded as one of the landmarks for the placement of artificial teeth in the prosthesis. Earlier studies were done in relation to anterior border of papilla but after extraction the incisive papilla recedes changing the position of anterior border. MATERIALS AND METHODS: In this study, 100 dentulous subjects were divided into two groups (males and females) with 50 in each group. Maxillary alginate impressions were made and base poured using levelling instrument to standardize all casts and surveyed on the surveyor for uniformity of the casts. The measured distances were analyzed using Student t-test analysis. RESULTS: The ovoid arch was the commonest arch form found in both males and females with slightly more prevalent in females. Analysis was done using Student t-test analysis and found that the mean distance from CI-IP was found to be at 12.85 mm and 12.39 mm in males and females, respectively. CONCLUSION: When square arch form (both male and female) mean CI-IP was compared with the total sample mean CI-IP, the mean CI-IP of square arch form was less than that of total sample with greater significance (P < 0.05). When ovoid arch form (both male and female) mean CI-IP was compared with the square arch form (both male and female) mean CI-IP, the mean CI-IP of ovoid arch form was greater than that of square arch form with greatest significance (P = 0).

Effect of Acidic Agents on Microhardness and Surface Morphology of Two Metal Ceramic Materials: An In Vitro Study.

AIM: The aim of the present study was to evaluate the effect of acidic agents on microhardness and surface morphology of two metal ceramic materials at various intervals. MATERIALS AND METHODS: A total of 120 metal ceramic disks were prepared and divided into two categories with 60 each. Each category was divided into two groups, group I (Made of IPS d.SIGN) and group II (made of VITA VMK), containing 30 samples each, which was subdivided into three subgroups each containing 10 samples A(i) B(i) acting as control, A(ii) B(ii) immersed in 0.5% HCl, and A(iii) B(iii) immersed in soft cola drink. Group I was tested for microhardness with Vickers microhardness testing machine at an interval of 0 minute, 24 hours, and 168 hours after immersing in acidic agents. Group II was observed for surface morphology changes with scanning electron microscope before immersion, and at an interval of 24 hours and 168 hours after immersing in acidic agents. The results were analyzed statistically, tabulated, and compared. RESULTS: Results revealed that there was a significant decrease in microhardness of IPS d.SIGN and VITA VMK when immersed in acidic agents at an interval of 0 minute, 24 hours, and 168 hours. There were significant surface morphological changes too of both the ceramics before and after immersing in acidic agents at 24 hours and 168 hours. CONCLUSION: Acidic agents evaluated in the present study affected microhardness and surface morphology of both the ceramics, and IPS d.SIGN is the most suitable and would be recommended in people who consume acidic beverages. CLINICAL SIGNIFICANCE: Durability of dental ceramics is very good, but degradation occurs when exposed to acidic agents. All the properties of ceramics are to be known in depth as they are widely used to construct various types of prostheses, and this has to be considered especially in people who consume acidic foods and drinks. How to cite this article: Priya KS, Kumar MP, Krishna VP, et al. Effect of Acidic Agents on Microhardness and Surface Morphology of Two Metal Ceramic Materials: An In Vitro Study. J Contemp Dent Pract 2019;20(11):1329-1334.

Effect of Temperature on Film Thickness of Two Types of Commonly used Luting Cements.

AIM: The aim of this study is to evaluate the effect of temperature change on film thickness of both types of cements. MATERIALS AND METHODS: Totally, 60 samples were prepared with 10 in each subgroup, thus comprising 30 in each group. Materials tested were glass ionomer cement (GIC) type I and zinc phosphate type I. Samples were manipulated with manufacturer's instructions and tested according to American Dental Association (ADA) guidelines. RESULTS: The mean values of film thickness were recorded for both groups I and II. In intragroup comparison of group 1, subgroup III (26.560 ± 0.489 urn) was found to have the highest film thickness followed by subgroup II (24.182 ± 0.576 urn) and the lowest in subgroup I (20.209 ± 0.493 urn). In intragroup comparison of group II, the film thickness recorded in subgroup III (25.215 ± 0.661 urn) was the highest followed by subgroup II (21.471 ± 0.771 urn) and the least in subgroup I (17.951 ± 0.654 urn; p < 0.01). In intergroup comparison of groups I and II, group II (21.545 ± 0.841) was found to have less film thickness than group I (23.650 ± 0.271). The results were found to be statistically significant (p < 0.01). CONCLUSION: Both zinc phosphate and GICs can be used satisfactorily for luting purpose. The temperature fluctuations have a direct influence on the film thickness. Zinc phosphate has less film thickness than GIC. CLINICAL SIGNIFICANCE: Zinc phosphate should be preferred over GIC in clinical practice, and more stress should be given in mechanical preparation of crowns for better retentive quality of prosthesis.