title: Effect of acidic pretreatment combined with a silane coupling agent on bonding durability to silicon oxide ceramic.
abstract: This study examined the effect of different acidic treatments and the role of a phosphate monomer in a silane coupling agent on the durability of the dual-cure resin cement/silicon oxide bond. Ceramic blocks (Vita Celay Blanks) were cut into multiple 3 mm-thick slices and polished using 600 grit SiC paper. Two pairs were left untreated [controls (CTRL)], two pairs were treated with 40% phosphoric acid and rinsed with water for 30 s (PA), and another two pairs treated with 20% hydrofluoric acid followed by 30 s water rinsing (HF). Half the specimens were silanated with Tokuso Ceramics Primer (TCP) (Tokuyama) and the other half with TCP formulated without phosphate monomer (TCP-NoPM). All the pairs were bonded with Bistite II dual-cure resin cement (Tokuyama) and light cured. After 24 h water storage at 37 degrees C, 0.7 mm-thick slabs were serially sectioned. Immediately, after 6 months and after 1 year of water storage, two slabs were randomly selected from each subgroup, and sliced into beams (6 x 0.7 x 0.7 mm) for the microtensile bond strength (muTBS) test. The muTBS data were statistically analyzed using multiple Wilcoxon Signed Rank tests (p < 0.05). Failure modes were determined using a confocal laser-scanning microscope. Ceramic surface morphology after the different acidic treatments was examined using an SEM. After 1 day, in the case of silane treatment with TCP, there were no significant differences in muTBS between the control and acid-treated groups (p > 0.05), whereas with TCP-NoPM, the muTBS of the control was significantly lower than the acid-treated groups (p < 0.05). All the TCP and acid-treated TCP-NoPM groups exhibited significant reductions in muTBS after 6 months (p < 0.05). After 1 year, the muTBS of the acid-treated TCP groups were not significantly different from the control TCP group (p > 0.05). There was also no significant difference between the HF-treated TCP and TCP-NoPM groups (p > 0.05) after 1 year, all exhibiting greater than 10 MPa tensile bond strength. It is suggested that acidic pretreatment of the ceramic surface does not improve the durability of the dual-cure resin cement/silicon oxide ceramic bond when an acidic phosphate monomer is present as an activator in a ceramic primer.
authors.affiliation: Division of Conservative Dentistry, Floor 25, Guy's, King's and St. Thomas' Dental Institute, Guy's Tower, Guy's Hospital, London Bridge, London, SE1-9RT, UK. richard.foxton@kcl.ac.uk
authors.forename: Richard M
authors.initials: RM
authors.lastname: Foxton
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nakajima
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miura
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000143:Acids; D001843:Bone Cements / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods; D003738:Dental Cements / Q000737:chemistry; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006858:Hydrofluoric Acid / Q000737:chemistry; D008027:Light; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water
chemical_list: D000143:Acids; D001843:Bone Cements; D003188:Composite Resins; D003738:Dental Cements; D017220:Dentin-Bonding Agents; D010710:Phosphates; D010756:Phosphoric Acids; D012821:Silanes; D014867:Water; D012822:Silicon Dioxide; C030242:phosphoric acid; D006858:Hydrofluoric Acid