feldspar and tri-n-butylborane

This study determined the bond strengths of adhesive resins joined to a feldspathic porcelain (VMK 68) for the purpose of developing the most durable surface preparation for the porcelain. Three porcelain surfaces-ground, air-abraded with alumina, and etched with hydrofluoric acid-were prepared. A two-liquid porcelain conditioner that contained both 4-methacryloyloxyethyl trimellitate anhydride (4-META) and a silane coupler (Porcelain Liner M) was used as the priming agent. Each of the two liquid components of the conditioner was also used individually in order to examine the effects of the respective chemical ingredients on adhesive bonding. Two methyl methacrylate (MMA)-based resins initiated with tri-n-butylborane (TBB) either with or without 4-META (MMA-TBB and 4-META/MMA-TBB resins) were used as the luting agents. Shear bond strengths were determined both before and after thermocycling. Shear testing results indicated that thermocycling was effective for disclosing poor bonding systems, and that both mechanical and chemical retention were indispensable for bonding the porcelain. Of the combinations assessed, etching with hydrofluoric acid followed by two-liquid priming with the Porcelain Liner M material generated the most durable bond strength (33.3 MPa) for the porcelain bonded with the 4-META/MMA-TBB resin (Super-Bond C&B).

Topics: Acid Etching, Dental; Adhesives; Aluminum Oxide; Aluminum Silicates; Analysis of Variance; Boron Compounds; Chemical Phenomena; Chemistry, Physical; Dental Bonding; Dental Porcelain; Humans; Hydrofluoric Acid; Materials Testing; Methacrylates; Methylmethacrylate; Methylmethacrylates; Potassium Compounds; Resin Cements; Silanes; Statistics as Topic; Stress, Mechanical; Surface Properties; Thermodynamics

This study determined the bond strength of an unfilled resin joined to a feldspathic porcelain for the purpose of evaluating the retentive performance of the prepared material surfaces. Porcelain disks (VMK 68 dentin) were either air abraded with alumina (AAA) or etched with one of the following five etchants: (1) ammonium hydrogen bifluoride (AHB); (2) acidulated phosphate fluoride (APF); (3) hydrofluoric acid (HFA); (4) phosphoric acid (PHA); and (5) sulfuric acid-hydrofluoric acid (SHF). Specimens ground with abrasive paper were also used as controls. After surface preparation, the two different sized porcelain disks were bonded together with a methyl methacrylate-based resin initiated with tri-n-butylborane (MMA-TBB resin). Shear bond strengths were determined both before and after thermocycling. Before the thermocycling, the greatest bond strengths (21.3 and 23.7 MPa) were generated with the use of the SHF and HFA agents, followed by the AHB agent (18.4 MPa). Reduction in bond strength after thermocycling was significant for all groups, although the SHF- and HFA-treated groups exhibited bond strengths greater than 15 MPa even after the thermocycling. The results indicated the effectiveness of the SHF- or HFA-etching for retaining the acrylic resin to the porcelain. However, ageing testing also revealed insufficient retentive characteristics of the acrylic resin by etching alone.

Topics: Acid Etching, Dental; Acidulated Phosphate Fluoride; Acrylic Resins; Aluminum Oxide; Aluminum Silicates; Ammonium Compounds; Boron Compounds; Dental Bonding; Dental Porcelain; Fluorides; Humans; Hydrofluoric Acid; Materials Testing; Methylmethacrylate; Phosphoric Acids; Potassium Compounds; Quaternary Ammonium Compounds; Stress, Mechanical; Sulfuric Acids; Surface Properties; Thermodynamics; Time Factors