![]() The American Dental Association Specification for elastomeric dental impression materials endorses a maximum negative change in dimensions to be 0.50% after a minimum of 24 h. Moreover, the distortion of the impression material during cast duplication of the same impression influences the accuracy and proper fit of the final restoration. Shrinkage on polymerization have long remained a major problem that affects directly the dimensional accuracy and stability of elastomeric impression material. Among the available and the most frequently, used elastomers in the market are the polyvinyl siloxanes and polyethers. Įlastomers or rubber base impression materials are the most widely used materials as secondary impressions as they meet most of the ideal requirements of an impression material. ![]() The advantages of using alginate include the low cost, comfort of the patient, the speedy and easy manipulation, and possibility of obtaining a satisfactory primary impression in one step. Alginate impression is usually used at the first dental visit to give an overview about the patient’s oral health status. ![]() Hydrocolloids are crucial material in every dental clinic with alginate being the most frequently used one. A wide range of elastic impression materials are available for dental use that can be categorized into two groups, hydrocolloids and elastomers. Elastomeric impression materials are currently one of the most popular options for definitive impressions in fixed and removable prosthodontics. Although a number of materials and techniques have provided adequate clinical results, the ideal impression material has not yet been found. Over years, a wide variety of impression materials were developed, all trying to achieve an impression that can perfectly reproduce the oral hard and soft tissues. An ideal impression material should have an adequate flow, sufficient working and setting time, good dimensional accuracy and stability along with elasticity. Accuracy of the final restorations depends on several parameters such as proper tooth preparation, operator and laboratory technician’s skills, and most prominently, the impression material and the technique used. The technical complexity in prosthodontic treatment has led to the development of indirect approaches in which the restoration is fabricated outside the oral cavity to be placed afterwards intraorally. The hybridization of polyvinyl siloxane and polyether yielded a promising material that combines the good merits of both materials and overcomes some of their drawbacks. The digital technique used could be a more reliable and an easier method for assessment of impression materials properties. Whereas, under wet conditions, the hybrid material showed higher prevalence of well-defined reproduction of details same as polyether but higher than polyvinylsiloxane that showed prevalence of details with loss of sharpness and continuity. With regard to the detail reproduction, the three tested materials were able precisely to reproduce the three grooves of the mold under dry conditions. The contact angles of the hybrid material before and after setting was significantly lower than the parent materials. The hybrid impression (0.035 mm) material showed significantly higher dimensional accuracy compared to the polyether (0.051 mm) but was not as accurate as the polyvinyl siloxane impression material (0.024 mm). Specimens were prepared and examination was made immediately after setting using digital images at a magnification of 16×. A metallic mold was used with three V shaped grooves of 20, 50, and 75 µm width. 19 and under wet conditions as per ISO 4823. The detail reproduction was measured under dry conditions according to ANSI/ADA Standard No. Hydrophilicity was assessed by contact angle measurements using AutoCAD software. ![]() Accuracy was calculated from the mean of measurements taken between fixed points on the casts using digital single-lens reflex camera to produce high-resolution digital pictures for all the casts with magnification up to 35×. Dimensional accuracy was evaluated through taking impressions of a metallic mold with four posts representing a partially edentulous maxillary arch, that were then poured with stone. This was done in an attempt to aid in solving the conflict between the different studies published by competitive manufacturers using different common manual approaches.Ī polyether, polyvinylsiloxanes and vinyl polyether silicone hybrid elastomeric impression materials were used in the study. This study aimed to compare the dimensional accuracy, hydrophilicity and detail reproduction of the hybrid vinylsiloxnether with polyether and polyvinylsiloxane parent elastomers using modified digital techniques and software.
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