An investigation into the interfacial bond strength of the titanium - ceramic system for dental application

Abstract

Failures that occur in titanium-ceramic restorations are of concem to dental clinicians. The formation of poorly adhering oxide on titanimu. at ceramic sinteling temperatures, causes adherence problems between titmlium <md ceranlic, wllich is the main limiting factor in the fabrication of titanium ceramic restoration. To overcome this problem tllis study investigated the effect of various surface treatments and cermuic types on the bond strength of tit<U1imu-ceranlic systcms and comparcd thcm to that of the Ni-Cr/ ceramic system. The following titmlimu surface treatmcnts wcre investigatcd:- polished, sandblasting with different grit size of 50, 125, 250Jlm, silicon dioxide and silicon rlitride coating, <Uld acid etching. Titmlium Ships were prepared, (n=15), following the protocol of ISO 9693:2000 mld divided into five study sections to make the comparison. The titanium-ceramic specimens were subjected to a three point flexural test. The groups were compared for their bond strength. SEM and SEMIEDS analyses were performed on the delanlinated titanium surfaces to ascertain bond failme. Section 1 investigated the effect of sUlface texture (s,mdblasting and polishing). A comparison between Nickel-Chromium alloy and titmlium to the appropriate ceranlic systems was made. The mean bond strength of sandblasted NickelShromium/ Vita VMK95, polished Ni-Cr/Vila VMK95, polished Titaruum/Vita VMK95 and 50Jlm sandblasted Titmlium/Vita VMK95 were 49.9-t±9.20, 44.13±7,47, 23.34±6.83, 39.15±5.17 MPa, respectively. The sandblasted Ni-Cr group was significantly higher tllan that of the other tested groups. The polished titmlium showed the lowest bond strengtll among the four groups. Section 2 evaluated, by means of a 3-point bendlllg test, the bond strcngtll of differcnt sandblasted titanium substratcs, (50Jlm, 125Jl111, 250Jlm), applied to three commercial low-fusing ceml1lic systems, (Vita Titankeranlik, Triceranl and Noritake). Noritake ceranuc had significantly higher bond strength than the other cemnlics. However, 110 significant difference v·,as found between Tricemm and Vita Titmlkeranuk. No significant difference was detected between the three smldblasting treaUuents (p=0.165). The bond sU'ength of the sandblasted TilNoritake groups (48.39-53.30) MPa was comparable to the smldblasted Ni- Crgroup. . Section 3 evaluated, by mean of a 3-point bending test, the bond strength of etched and coated titmlium substrates combined to Vita Titmlkeranlik ceranlic. The results showed that 10% acid etched Ti, polished Ti, and the polished/silicon sputtered Ti groups have the lowest flexural bond strength among all study groups. The flexural bond strength of the polished! Si3N4 sputtered Ti group was significantly Iligher (P<O.OO I) tllan Ilmt ofpolished Ti or polished! silicon spultered Ti groups. Section 4 investigated the eJIect of titarulUll specimens' preparation method; i.e. casting vs machining, on the fle:mral bond strcngth of ceranlic to titanium. The mean fleXtrral bond strength of the C<'lst Ti specimens was 44.17±II.9I MPa while the mean bond strength of the machined Ti was 43.33±6.72 MPa with a range between 26.94 to 53,41 MPa. No sigllificant difference between the cast <md machined groups was found (P= 0.696). Section 5 investigated the effect of thermocycling on the bond strength of the three cenmlics systems to titanium. The mean bond strength of non-thermocycled Ti/Vita Titankeranlik, Til Triceranl, and TilNoritake groups were 44.74±11.92, -l0.37±10.25, 52.28±5.31 MPa, respectively while the thcrmocycled groups were 38.6H7.7-l, 37.53±9.30 and 5I.I9±7AI MPa. respectively. Supplied by The British Library - 'The world's knowledge'EThOS - Electronic Theses Online ServiceGBUnited Kingdo