Air abrrasion effect on metal-ceramic bonding

Uvod: Kovinsko-porcelanski zobni nadomestki v slovenskem prostoru še vedno veljajo kot najbolj uporabljeni, vsestranski in estetsko zadovoljivi. Navadno je osnovna konstrukcija izdelana iz zlitine, ki je prekrita z dentalnim porcelanskim plaščem. Jakost vezi med zlitino in porcelanskim plaščem pa je odvisna od več spremenljivk. Pri meritvah jakosti mehanske oprijemljivosti med osnovno kovinsko konstrukcijo in porcelanskim plaščem smo preizkušali predvsem odvisnost jakosti mehanske oprijemljivosti glede na velikosti Al2O3 delcev s katerimi smo jo speskali. Pomembno je, da poznamo vse spremenljivke in lastnosti vzorcev ter, preizkuse pripravimo v enakih pogojih. Namen: Namen zaključnega dela je pregledati že obstoječo literaturo ter, raziskav in preizkusiti katera končna obdelava z Al2O3 delci zagotovi najboljšo mehansko vez. Metode dela: V začetnem delu smo uporabili deskriptivno metodo s pregledom literature in rezultatov že opravljenih podobnih raziskav na temo diplomskega dela. V zaključku pa smo predstavili rezultate strižne napetosti, ki smo jih eksperimentalno določili. Rezultati: Predstavljeni so postopki izdelave treh različnih vrst preizkušancev obdelanih z različno velikostjo delcev pri peskanju in jakost njihove mehanske oprijemljivosti pri preizkusih. Razprava in zaključek: Zaključili smo z analizo rezultatov, ki smo jih pridobili z preizkusom strižne trdnosti. Izračunali smo strižne napetosti različno obdelanih preizkušancev. Ugotovili smo da so največje sile porušitev in strižne napetosti dosegli preizkušanci obdelani 250-?m Al2O3 delci. Zato lahko sklepamo, da optimalen mehanski oprijem med zlitino in dentalnim porcelanom, ter s tem manjše tveganje za nastajanje razpok porcelanskega plašča zagotavlja obdelava z delci velikosti 250-?m.Introduction: Metal-porcelain dental prothetics in Slovenija are still considered to be the most widely used, versatile and aesthetically satisfactory. Usually the basic construction is made of an alloy covered with a dental porcelain coat. However, the strength of the bond between the alloy and the porcelain coat depends on several variables. In measuring the strength of mechanical adhesion between the basic metal structure and the porcelain coating, we mainly tested the dependence of the mechanical properties on shear stress strength. The adhesion depends on the size of the particles we used to sandblast the alloy construction. It is important that we know all the variables and properties of the samples, and prepare the experiments under the same conditions. Purpose: The purpose of this experiment is to research and review the existing literature, and to discover which sandblasting with Al2O3 particles provides the best mechanical bond. Working methods: In the initial part we used the descriptive method with a review of the literature and the results of already conducted similar research on the topic of the diploma work. In conclusion, we present the results of the mechanical metal-ceramic adhesion by variously prepered samples sandblasted with different sizes of Al2O3 particles. Results: We prezented the procedures for the production of three different types of samples who were sandblasted with different particle sizes and the strength of their mechanical adhesion during the tests. Discussion and conclusion: We concluded by analyzing the results obtained by the shear strength test. We calculated the shear stresses and bursts of differently processed specimens. We found that the maximum shear strength forces of bursting and shear stresses were achieved with samples sandblasted with 250-?m Al2O3 particles. Therefore, it can be concluded that optimum mechanical adhesion between the alloy and dental porcelain, and hence of lower risk for cracking the porcelain coat, is ensured by sandblasting the metal frame with particles 250?m Al2O3 particles