Purpose:The purpose of this within-subject crossover clinical trial was to compare and evaluate the chewing efficiency, masticatory bite force, and patient satisfaction with conventional dentures and two implant-retained mandible overdentures after 4 weeks of usage.Method:This within-subject crossover clinical trial was carried out in the Department of Prosthodontics in K.D Dental College and Hospital. A total 15 patients were selected for the study. To report the changes in chewing efficiency by chewing 6gms of peanuts with 40 chewing strokes and comparing the particle size of the chewed material between two implant retained mandibular overdenture with that of conventional denture using micro vu excel gantry type visual measurement machine. To report changes in masticatory bite force after transition of conventional complete denture patient to implant retained overdenture after using the prosthesis for four weeks each and recorded by digital transducer. To assess the patient satisfaction after transition of conventional complete denture patient to implant retained mandibular overdenture with help of OHIP edent patient satisfaction questionnaire.Results:The chewing efficiency for implant retained overdenture increased significantly than that of conventional denture. The particle size decreased to 76.34% for implant supported overdenture than that of conventional denture. The chewing strokes required by conventional denture was 69 strokes and that by implant supported overdenture which was 40 strokes to get the same mean particle size. The patients satisfaction after receiving the implant retained overdenture was significantly higher than that of complete denture.Conclusion:The provision of two mandibular implants significantly improves measures of oral function and better quality of life for edentulous patients.

Recording and transferring of accurate existing occlusal records is of prime importance for a successful restoration. An ideal occlusal registration material should provide minimal resistance to mandibular closure during the registration of maxillomandibular relationships. Interocclusal bite registration materials are partly responsible for accurate precision and occlusal quality of final prosthetic restorations when used for mounting casts on the articulators. The aim of selecting this study is to compare different types of recent interocclusal recording materials and to find the best among them which can resist a constant compressive load and will give the least inaccuracies. In the present study compressive resistance of four interocclusal recording materials viz. Imprint bite, Vitual refill, Jet bite and Ramitec at various thickness (2, 5, 10 and 20 mm) when subjected to a constant compressive load of 25 N was studied. The thickness of the interocclusal recoding materials were selected to simulate various clinical situations. For standardization, the specimens were stored at room temperature for 24 h to simulate the time between clinical and laboratory phases, N = 20 specimens from each group was selected (making a total sample size of N = 80). The SPSS version 17 has been used, two way ANOVA was applied to compare different types of recent interocclusal recording materials, p value ≤0.05 was considered statistically significant. A total of 80 samples were fabricated. Results of two-way analysis of variance (p ≤ 0.05) indicated that there was a significant difference in compressive resistance among the materials of each thickness. The 2 mm thickness specimens showed the least compression and 20 mm thickness specimen showed maximum compression under a constant load of 25 N for all the four materials tested. Virtual Refill bite registration material showed the least compression value than Imprint bite polyvinylsiloxane registration material, Ramitec polyether bite registration material and Jet bite polyvinylsiloxane registration material with negligible error of 0.04 mm found in 2 mm thickness. The results of foregoing study showed that Virtual refill having greater resistance to compression than other interocclusal recording material at various thickness. It exhibit minimal distortion during compression and give clinician the opportunity to make only minimal adjustments to the restorations that were delivered from the laboratory and avoid unnecessary use of chairtime, or repetition of some clinical and technical stages.

The purpose of this study was to compare the effect of seven different alloy surface treatments on the bond strength of the porcelain-metal interface. Three layers of opaque porcelain and a measured thickness of dentin porcelain were applied to nickel-chromium alloy, A tensile bond strength test was used. The alloy surface treatment that exhibited the highest bond strength was sandblast + surface grinding + sandblast + de-gas, whereas the alloy surface treatment that exhibited the lowest bond strength was sandblast + surface grinding + sandblast + steam cleaning + de-gas. There was a significant difference between the two methods (P < 0.05). It was concluded that de-gassing the alloy prior to porcelain application increased the bond strength and excess surface grinding of the alloy reduced bond strength; steam cleaning the alloy surface prior to de-gassing and porcelain application also significantly reduced the bond strength.

Vinyl polysiloxane (VPS) impression materials have application in a wide variety of situations in both fixed and removable prosthodontics. A major limitation of VPS impression materials is their hydrophobicity. There are two aspects of this problem, the wettability of the polymerized impression by dental gypsum materials and the ability of the unpolymerized material to wet intraoral tissues. To address this problem, manufacturers have added surfactants and labelled these new products as "hydrophilic vinyl polysiloxane." The purpose of this study was to evaluate and compare dimensional accuracy and surface detail reproduction of four hydrophilic VPS impression materials, when used under dry, moist, and wet conditions. A total of 180 samples were made of stainless steel die similar to as described in ADA sp. no. 19. The die was scored with three horizontal and two vertical lines. Impressions were made under dry, moist and wet conditions. Dimensional accuracy was measured by comparing the length of the middle horizontal line in each impression to the same line on the metal die, by using Universal Length Measuring machine. A 2-way ANOVA was performed on the percentage change data for measured lengths of the 4 impression materials under the 3 conditions to evaluate dimensional accuracy. Surface detail was evaluated in two ways: (1) by use of criteria similar to ADA sp. no. 19 for detail reproduction, and (2) by use of a method that categorized the impressions as satisfactory or unsatisfactory based on their surface characteristics: presence of pits, voids, or roughness. Pearson X2 (α = 0.05) was used to compare surface detail reproduction results. Conditions (dry, moist, and wet) did not cause significant adverse effects on the dimensional accuracy of all the four material. With both surface detail analyses, dry, moist, and wet conditions had a significant effect on the detail reproduction of all the four materials (P < 0.05). The study concluded that the dimensional accuracy of all the four impression materials tested was well within ADA standards. Best surface detail results were obtained only under dry conditions for all the four materials.

Considering the importance of the occlusal plane orientation in complete denture prostheses, a study was conducted on the relationship between this plane with ala-tragus and Camper's lines in soft tissue among individuals with class I, class II and class III occlusion. The aim of the present study was to define the best soft tissue index by which the location and inclination of the occlusal plane in complete dentures could be established. A total of 60 subjects were selected for the study. Lateral cephalograms of these subjects were obtained. Tracings and analysis was done to confirm to the skeletal relationship of subjects to be class I (normal), class II (prognathic maxilla) and class III (retrognathic maxilla). 20 Subjects of each group were screened for further analysis. Radiopaque markers were attached to the intended points on soft tissue and then standard lateral cephalograms were obtained from each subject. The angles between the following lines were measured: Occlusal line, Camper's line (ala-porion), AT1 (ala-superior border of tragus), AT2 (ala-mid-tragus) and AT3 (ala-inferior border of tragus). The mean values and standard deviations were calculated for all the groups. The mean values calculated were subjected to repeated ANOVA test and significance was evaluated. Comparison of the results by the ANOVA test exhibited a significant difference. In class I subjects, it was evaluated that in 75 % individuals, the posterior reference point was found to be the mid-tragus; of class II subjects, in 60 % individuals, the posterior reference point was found to be the mid-tragus; and of class III subjects, in 75 % individuals, the posterior reference point was found to be the inferior border of tragus.