sodium-hypochlorite and tri-n-butylborane

By altering either ferric chloride concentration in 10% citric acid (1% ferric chloride = 10-1; 5% ferric chloride = 10-5; 10% ferric chloride = 10-10) or conditioning periods with an aqueous mixture of 1% citric acid and 1% ferric chloride (1-1), the influence of dentin substrate on bond strength and hybridized dentin in wet bonding of 4-META/MMA-TBB resin was examined.. Dentin surfaces of fresh bovine incisors were conditioned either with 10-1, 10-5, or 10-10 mixtures for 10 s (10-1-10s, 10-5-10s, 10-10-10s groups) or with a 1-1 mixture for 5, 10, 30 or 60 s (1-1-5s, 1-1-10s, 1-1-30s, 1-1-60s groups). Rinsed, demineralized dentin samples were kept wet, primed with 5% 4-META in acetone for 60 s, and bonded with 4-META/MMA-TBB resin. Bonded specimens were trimmed to a mini-dumbbell shape for tensile testing. The cross sections of bonded specimens were modified with HCl and NaOCl in order to assess the hybrid layer. The fractured surfaces of specimens and the hybridized dentin were investigated with SEM.. No significant difference (p > 0.01) in tensile strength was identified between 10-1-10s and 10-5-10s groups (30 MPa), 10-10-10s and 1-1-5s groups (15 MPa), and the three groups conditioned by 1-1-10s, -30s and -60s (40 MPa). The thickness of the hybrid layer increased with increasing either ferric chloride or conditioning periods.. The concentration of ferric chloride in 10% citric acid for wet bonding must be less than 5% in order to provide a reliable bond. When applied from 10 to 60 s, the 1-1 conditioner provided hybridized dentin with reliable tensile bond strength. The thickness of the hybrid layer did not influence the tensile bond strength.

Topics: Acetone; Acid Etching, Dental; Acrylic Resins; Analysis of Variance; Animals; Boron Compounds; Cattle; Chelating Agents; Chlorides; Citric Acid; Dental Bonding; Dentin; Ferric Compounds; Hydrochloric Acid; Methacrylates; Methylmethacrylate; Microscopy, Electron, Scanning; Oxidants; Resin Cements; Sodium Hypochlorite; Statistics as Topic; Stress, Mechanical; Surface Properties; Tensile Strength; Time Factors; Water

This study compared the capability of three composite resin cements to sustain a standard endodontic dowel. All of the systems incorporated some form of smear layer removal on the dentin of the endodontic channel. One system that used a methyl ethyl ketone drying agent provided inadequate clinical resistance to dislodgment of 5.4 DaN. A second cementing system that used only smear layer removal resisted loads at 54.7 DaN. The third cementing regimen that included a surface-initiated dentinal adhesive and smear layer removal recorded retention of 77.4 DaN. This study supported the concept that passively cemented dowels with composite resin can be as effective as actively seated dowels.

Topics: Acrylic Resins; Bisphenol A-Glycidyl Methacrylate; Boron Compounds; Butanones; Cementation; Chlorides; Citrates; Citric Acid; Composite Resins; Dental Bonding; Dental Cements; Dental Implantation, Endosseous, Endodontic; Edetic Acid; Ferric Compounds; Humans; Methacrylates; Methylmethacrylates; Polyethylene Glycols; Polymethacrylic Acids; Prosthesis Failure; Root Canal Irrigants; Root Canal Therapy; Smear Layer; Sodium Hypochlorite; Stress, Mechanical