MAIN PROPERTIES OF ABRASIVE DENTISTRY MATERIALS UTILIZED IN POLISHING OF REMOVABLE DENTURE BASES
Ukraïnsʹkij stomatologìčnij alʹmanah
The requirements to the quality of dental prostheses are currently very high. All dental prostheses need thorough final finishing through filing and polishing in order to obtain smooth, polished, shiny and esthetic surface. In addition to comfort and aesthetics this guarantees high hygienic quality of dental prostheses and extends their operational characteristics. Smooth and even surface of plastic or thermoplastic prostheses can more efficiently resist aging and decay caused by the change of
... d by the change of temperature and bacterial flora activity which typically occur in the mouth cavity. Modern orthopedic dentistry utilizes various abrasive materials for filing and polishing of removable dentures made from different materials. Filing is the method of removing roughness and unevenness from the surface of dentures. Polishing is the final process of finishing aimed at obtaining smooth, shiny surface of dentures. It has been proved that rough and badly polished surface of dentures can cause significant patient's discomfort and complicate hygiene of the mouth cavity. Together with the aggressive environment of the mouth cavity, such surfaces can lead to dental plague and tartar deposit, which, correspondingly, leads to bad smell, stomatitis and other dental and general illnesses. It has been proved that high quality finishing of the surface of removable dentures contributes to the improvement of their sustainability, durability and aesthetic characteristics. Well-polished surface of removable dentures more efficiently resists the processes of destruction, such as aging and decay, caused by the change of temperature and bacterial flora activity. The analysis of bibliography has shown that the process of polishing and the quality of the surface under work depend on a number of factors. The most significant role belongs to the size of abrasive particles, the pressure of abrasive on material and its thermal conductivity, the speed at which abrasive particles move along the surface. Grains of the size 0,15-0,75 mm are used most often. It has been specified that coarse polishing can utilize grains of bigger size reaching 1,5-2 mm. It has been proved that the pressure of abrasive should be light in order to prevent the damage of dentures or instruments. Moreover, excess pressure can cause overheating of an instrument or the surface of dentures being polished. It has also been demonstrated that even short-term high temperature exposure can result in polymer deformation which reduces sustainability and durability of removable dentures. It is known that overheating can be avoided on condition of following the basic rules of polishing. Orthopedic dentistry utilizes pumice, silicate or aluminum oxide, silicone dioxide as abrasive filler. The particular interest presents the study of the efficiency of zirconium silicate as an abrasive component of polishing paste for finishing of thermoplastic polymer bases and providing full gloss of the surface. Stearin, paraffin, wax, petrolatum are used as the components of surfactants, as they demonstrate low surface tension and facilitate spreading the paste on the polished surface. There is not a wide range of locally produced polishing pastes utilized in dentistry. They leave traces, microscratchings; do not allow obtaining even, smooth shiny surface of dentures with thermoplastic polymer basis. Finishing of removable dentures requires a lot of time and expenses from professionals.