EVALUATION OF PHYSICAL AND MECHANICAL PROPERTIES OF ASH-FREE ACRYLIC PLASTIC «MОDЕPLAST» TO SIMULATE PIN-CAST DESIGNS

Abstract

Introduction. Lesions of hard tooth tissues often results in loss of the tooth crown. Addition to decay, loss of teeth can cause a variety of other pathological conditions of the hard tissues is of course non-carious lesions, defective therapeutic treatment, and most of them are injured in 32 % of cases. The absence of the tooth crown causes uneven distribution of chewing pressure on occlusal surface of dentition, which in turn changes the function of mastication and leads to further destruction and the emergence of dentition deformities. To avoid this, it is necessary to artificially restore the dentition. High efficiency chewing function using the roots defined by the fact that the prostheses, which are fixed spiralis at the root, chewing pressure is passed naturally through the periodontium. This causes the high prevalence of the use of the pincast dentures. Also an important place in the prosthetic dentistry clinic is the quality and ease of use of materials, which are made of different monolithic design. Together with the accredited research laboratory of dental materials and products of JSC «Stoma» (Kharkov) and department of prosthetic dentistry Kharkiv national medical University developed a new material «Modeplast» to simulate pincast prosthetic components. The purpose of the study. Quality assessment of physical and mechanical properties of acrylic plastic ashless «Modelpast» to model pin tumbler designs compared to similar foreign counterpart. Materials and methods. To compare the quality of the physical and mechanical properties and quality foreign analogues was taken ashless acrylic plastics for modeling orthopedic constructions «Pi-Ku-Plast», Bredent, Germany The study was performed in conditions accredited research laboratory of dental materials and products of JSC «Stoma» on 30 samples (15 samples «Modeplast», JSC «Stoma» and 15 samples «Pi-Ku-Plast», Bredent, Germany) by methods provided by ISO-10139, according to which physical and mechanical properties of the investigated materials for the manufacture of pin tumbler designs include: appearance, curing time (min), the mass fraction of ash (%), thermal fluid and quality of the finished prosthetic restoration. Exterior acrylic plastic ashless examined by visual inspection. To calculate the curing time at 23±0,5 was taken and mixed 4±0.2 g of powder and 5±0.1 ml of fluid each rubber material in a special container. To determine the thermal stability of fluids studied materials, they put a thermostat which was pre-heated to 95±0,1 Celsius for 8 hours and watched consistency. To calculate the ash content in plastics, were taken 3±0,1 g of finished plastic and placed in a muffle furnace with constant heating temperature equal to 800±15°C. To maintain this temperature mufel a thermostat. The quality of the finished structures is studied by fitting the root canal using a mass of C-corrective silicone impression material. Results. During their appearance liquid acrylic plastics ashless «Modelpast» and «Pi-Ku-Plast» transparent red color, without visible impurities and sediment, coinciding with the regulations. Time ashless curing acrylic plastic «Modeplast» (Ukraine) is 3,0±0,02 minutes in «Pi-Ku-Plast» (Germany) 3,0±0,04, which was significantly (P <0,05) not different. This enables us to state that on this property «Modeplast» is not different from the commonly-used foreign counterparts. In terms of thermal stability of both liquid samples ashless acrylic plastic fully comply with regulatory requirements and does not change the physical condition. Mass fraction of ash in acrylic plastic ashless «Modeplast» is 0,015±0,01%, which was significantly (P<0.05) less than «Pi-Ku-Plast» (0,026±0,015). To evaluate the quality of the finished designs were examined and implanted 45 patients with defects of the frontal coronal tooth. Modeling cast metal tabs conducted only direct method. The paper used different types of fixed structures based on. Solid stump pinning tabs made of plastic ashless «Modeplast» and «Pi-Ku-Plast». Total tab was produced 52 pieces. 26 of «Modeplast» and 26 of «Pi-Ku-Plast» In 3 cases out of 26 made from «Pi-Ku-Plast», and this – 11.5 %, and in 2 cases out of 26 made a «Modeplast», and it is – 7.5 % was poor quality landing in root canal endowments casting for the poor, as the layer of silicone material corrective mass was distributed unevenly layer over the entire area adjacent to the root canal.