Potassium fluoride,anhydrous
           Potassium fluoride,extra pure
           Potassium fluoride,Granular
           Silicon Dioxide
           Hydrofluoric acid
           Synthetic Cryolite
           Potassium Fluoaluminate
           Ammonium bifluoride
           Potassium Bifluoride
           Aluminium fluoride
           Sodium fluoride
           Potassium Fluorosilicate
           Fluorosilicic Acid
           Sodium silicofluoride
           Potassium Hydroxide Flakes
           Magnesium Fluoride
           Magnesium fluorosilicate
           Barium Fluoride
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Materials and Methods: Ceramic and composite blocks (N = 30) were divided into six groups (n = 5) and sub-jected to the following conditioning procedures: G1: 9.6% hydrofluoric acid  for 20 s + silane (RelyX Ceramic Primer, 3M ESPE) + resin cement (Panavia F2.0, Kuraray) (control); G2: HF (20 s) + silane + heat treatment in furnace (HTF) (100°C, 2 min) + resin cement; G3: silane + HTF + resin cement; G4- HF (20 s) + silane + heat treatment with hot air (HTA) (50 ± 5oC for 1 min) + resin cement; G5: silane + HTA + resin cement; G6: silane + resin cement. The microtensile bond strength (MTBS) test was performed using a universal testing machine  (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using a stereomicroscope and SEM to categorize the failure types. The data were statistically evaluated using one-way ANOVA and Tukey’s test (5%).

Heat treatment procedures for the pre-hydrolyzed silane either in a furnace or with the application of hot air cannot replace the use of Hydrofluoric acid gel for the adhesion of resin cement to feldspathic ceramic. Yet when mean bond strengths and incidence of pre-test failures are considered, furnace heat treatment delivered the second best results after the control group, being considerably better than hot air application.

According to Ministry of Public Security, anhydrous hydrofluoric acid is highly toxic inorganic Class A, included in the "List of key regulatory Hazardous Chemicals," according to the State Administration of Work Safety "dangerous chemical safety regulations", in addition to obtaining business license law external card business, other entity to purchase highly toxic chemicals, should be to the people's government at the county level public security organs apply for highly toxic chemicals to purchase a license. The school official said engraving glass with hydrofluoric acid is a high school senior year must do the experiment, and for the school to use toxic chemicals to the students to do experiments, the local education ingored, said the school used laboratory supplies of non-interference. Obviously, for the accident, long-term neglect of the education sector supervision has responsibility.