School of Dental Medicine, University of Zagreb, Croatian Dental Society - Croatian Medical Association
Abstract
A cross-linking agent, ethylene glycol dimethacrylate, which is added to poly (methyl methacrylate) (VMMA) denture base resins to improve crazing resistance, has little effect on the mechanical properties o f the resultant denture base. A poly functional cross-linking agent, butadiene acrylate (BDA), has been considered to have a greater cross-linking efficiency and thus altering the mechanical properties. The purpose o f this study was to investigate the effect o f BDA on the impact strength o f a PMMA specimens containing 0%, 1%, 4% and 12% BDA o f monomer volume which had been produced by a conventional dental dough-moulded technique as determined. Mean impact strengths were 1.789 KJ/m2 (SD 0.254), 1.720 KJ/m2 (SD 0.273); 1.715 KJ/m2 (SD 0.280) and 1.838 KJ/m2 (SD 0.244), respectively. These differences were not significant (p >0.05) as tested by the analysis o f variance. It was concluded that the cross-linking agent BDA did not affect the impact strength of the PMMA resin specimens.U svrhu povećanja otpornosti poli(metilmetakrilatnih) proteznih smola na lomove i stvaranje napuklina, monomer-kapljevini se tvornički dodaje tvar za umrežavanje, najčešće etilen-glikol-dimetakrilat (EGDMA), koji se u tome smislu nije pokazao učinkovitim. Ovo istraživanje je provedeno s pretpostavkom da bi polifunkcionalna tvar za umrežavanje, kao što je to butadin - akrilat (BDA), mogla imati veći učinak na umrežavanje i poboljšanje mehaničkih svojstava poli(metilmetakrilatnih) smola. Ispitivana je udarna čvrstoća Zwick-postupkom poli(metilmetakrilatnih) pripravaka, podijeljenih u četiri skupine s obzirom na količinu tvari za umreživanje (0%, 1%, 4% i 12%), te dobivenih uobičajenom kivetnom tehnikom oplopolimerizirajućeg postupka. Vrijednosti za udarnu čvrstoću pripravaka po skupinama iznosile su: 0% BDA - 1,789 KJ/m2 (SD 0,254); 1% BDA - 1,720 KJ/m2 (SD 0,273); 4% BDA - 1,715 KJ/m2 (SD 0,280) i 12% BDA - 1,838 KJ/m2 (SD 0,244), a razlike među skupinama nisu se pokazale statistički značajnim (p > 0,05). Zaključeno je da istraživana tvar za umrežavanje (BDA) nije doprinijela poboljšanju udarne čvrstoće poli(metilmetakrilatnih) pripravaka
