An in vitro assessment of optimizing implant positions in bilateral distal extension implant-assisted removable partial dentures: A microstress analysis.

AIM: The aim of this study was to analyze and compare the stress distribution on dental implants in various positions when used with implant-assisted removable partial dentures. SETTINGS AND DESIGN: This was an in vitro study. MATERIALS AND METHODS: A model representing a mandibular bilateral partially edentulous condition, with missing premolars and molars, was fabricated using epoxy resin. Two implants of similar diameter measuring 4.0 mm × 10 mm (Dentium, Korea) were inserted in the second molar and the second premolar region on either side of the model for comparing the biomechanical effect of various implant locations. Two types of loads 100N and 125N were applied vertically using universal testing machines in the premolar and molar regions. The loads on the implants beneath the cast partial denture were measured by physical stress analysis using a microstrain gauge. STATISTICAL ANALYSIS USED: A comparison of maximum stress observed at the premolar versus molar regions due to the application of the 100N and 125N loads was done using the Mann-Whitney U-test. RESULTS: In physical stress analysis, obtained results were statistically analyzed, and the result was statistically not significant (P = 0.435 at 100N and P = 0.718 at 125N) in positional changes of implant. CONCLUSION: In the current study, the statistical analysis of physical stress revealed no significant differences in stress values between the loadings at the premolar and molar regions. This suggests that the implant can be placed in either the premolar or molar region based on the availability of bone without affecting stress distribution.

Three-dimensional-Printed Malo Bridge: Digital Fixed Prosthesis for the Partially Edentulous Maxilla.

Screw-retained implant restorations have an advantage of predictable retention, retrievability, and lack of potentially retained subgingival cement. However, a few disadvantages exist such as need for precise placement of the implant for optimal and esthetic location of the screw access hole and obtaining passive fit. Malo bridge with customization of abutment can establish a precise patient's gingival architecture. It is the most esthetically advanced form of fixed prosthodontic rehabilitation for complete and partially edentulous patients. This prosthesis is combined with three-dimensional (3D)-printed computer-aided design and computer-aided manufacturing technology to gain the precise fit and added esthetics. It also has advantages such as elimination of screw access openings, makes it possible to remove and repair the fractured porcelain of the individual crown without removing the whole structure, excellent precision, avoids casting errors, light weight, reduced complexity of laboratory procedures, high definition of morphology, and time-consuming. This case report presents replacement of partially edentulous maxilla using 3D-printed Malo bridge.

Evaluation of the polished surface characteristic of cobalt-chrome castings subsequent to various finishing and polishing techniques.

Finishing and Polishing constitutes an essential requisite after the fabrication of removable partial dentures. Improper finishing and polishing of cast framework will adversely affect the quality of functional units of partial dentures due to reduced dimensions. In this study the polished surface characteristic and loss of weight of the casting were evaluated and compared following different finishing and polishing techniques. A total number of thirty test specimens were cast and each surface finishing and polishing technique was carried out with a high speed polishing motor and an electropolishing unit under standardised conditions. Surface roughness was evaluated by means of a surface roughness analyzing instrument, Perthometer. The loss of weight due to the metal lost was observed on a sensitive electronic balance. The results of polishing technique employed with G3 group revealed better surface characteristic. It may be understood that sandblasting causes initial roughness and the sequence of coarse cylindrical abrasive, Black hard rubber polisher (coarse grit-Dentauram), Grey hard rubber polisher (Med-grit-Dentauram), Green hard rubber polisher (Fine-grit-Dentauram), Grey flexible rubber polisher (Fine grit-Renfert), felt buff with pumice slurry and felt buff with green polishing compound (Degussa) produced improved surface in this case. The loss of weight due to metal lost show concern with technique groups G4, G5, G6. It can be avoided by judicious sandblasting and application of proper grit of abrasive agents.