“Platform switching”: Serendipity.

Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

An evaluation of the mechanical properties of Type III and Type IV gypsum mixed with two disinfectant solutions.

Background and Objectives: This in-vitro study was conducted to evaluate the strength and properties of Type III and Type IV gypsum mixed with disinfectant solutions. Materials and Methods: Type III and Type IV gypsum were used for the study. Three different mixing solutions namely waterqueous solutions of 0.525% sodium hypochlorite and 2% glutaraldehyde were used. Gypsum materials were subjected to further modification by adding a mixture of 1.0% gum arabic and 0.132% calcium hydroxide before mixing with the disinfectant solutions, at two different liquid/powder (L/P) ratios for each. Both, the unmodified and the modified gypsum were tested for compressive and tensile strength after one hour and one week from the start of the mix. The crystalline configuration of the fracture fragments of the unmodified and modified set gypsum were studied under the scanning electron microscope. Results: The disinfectant solutions reduced the strength of both Type III and Type IV gypsum. Water showed higher-strength, which was followed by 0.525% sodium hypochlorite and 2% glutaraldehyde. The modified Type III and Type IV gypsum with reduced L/P ratio also showed strength values less than that of the control groups. Interpretation and Conclusion: Chemical disinfectants reduced the strength of gypsum when used as water substitutes. Gum Arabic and calcium hydroxide additives permitted lower L/P ratio, however, there was still excess water retained in the set gypsum that lowered the strength values of Type III and Type IV gypsum. Hence, further reduction of L/P ratio may increase the properties of the modified Type III and Type IV gypsum.