Three-year clinical evaluation of the Clearfil Liner Bond system.

Modern dental adhesive systems have improved the bond of restorative materials to mineralized tooth structures. The purpose of this study was to evaluate the clinical performance of composite restorations placed in abrasion and erosion lesions using the Clearfil Liner Bond dental adhesive system. Following ADA clinical guidelines for dentin and enamel adhesive materials, 62 facial class 5 smooth surface erosion or abrasion lesions with no undercuts and involving primarily root surfaces were restored in 25 adult male and female patients. The teeth were restored without preparations using Clearfil Liner Bond and Clearfil Photo Anterior composite resin. The clinical performance of the restorations was assessed by two examiners at baseline, 6 months, 1, 2, and 3 years using the following evaluative parameters: color match, marginal discoloration, and marginal integrity according to modified Ryge criteria; the presence or absence of recurrent decay; pre- and postoperative sensitivity; and restoration failure due to loss of retention or other causes. At the end of 3 years, four of the 55 restorations remaining in the study failed due to lack of retention (92.7% retention rate). The evaluations of the other clinical parameters demonstrated excellent performance by this system.

Shear bond strength required to prevent microleakage of the dentin/restoration interface.

The purpose of this in vitro study was to determine the relationship between the shear bond strength [SBS] of seven dentin bonding systems to dentin and the quantitative microleakage [ML] of Class V preparations in dentin restored with these systems. The systems evaluated were All-Bond/Bisfil-P [A]; Syntac/Heliomolar [B]; XR-Bond/Herculite [C]; Scotchbond 2/Silux [D]; Denthesive/Charisma [E]; Prisma Universal Bond 2/Prisma AP.H [F]; and Tenure/Perfection [G]. The 115 specimens were removed from the assembly apparatus and stored in saline at 37 degrees C for 24 hours, the SBS determined and expressed in MPa. Fifteen Class V preparations in dentin were restored with each of the bonding systems, thermocycled 500x in 2% methylene blue solution between 50 degrees C and 8 degrees C, and the ML determined by means of a spectrophotometric dye-recovery method. The ML was expressed in microgram dye/restoration. The data were analyzed by ANOVA, Student-Newman-Keuls test, and linear regression analysis. The SBS in MPa were: A:17.2 +/- 3.6; B:15.9 +/- 2.1; C:15.4 +/- 3.7; D:11.6 +/- 2.2; E:10.7 +/- 3.7; F:10.4 +/- 2.5; G:8.2 +/- 3.9. The ML in microgram dye/restoration were: A:2.6 +/- 1.2; B:2.6 +/- 1.0; C:2.2 +/- 1.9; D:3.1 +/- 2.9; E:4.6 +/- 4.2; F:2.6 +/- 2.5; G:4.4 +/- 4.1. SBS = 20.91-2.60 [microgram dye]. The results suggest that a SBS of +/- 21 MPa may reduce ML to near zero.

Quantitative microleakage of six dentin bonding systems.

This in vitro study evaluated the quantitative microleakage (ML) of (A) Gluma/Pekafill, (B) Tripton/Opalux, (C) Syntac/Heliomolar, (D) Prisma Universal Bond 2/Prisma AP.H., (E) Prisma Universal Bond 3/Prisma AP.H., and (F) Clearfil PhotoBond/Photo Clearfil Bright to cementum (dentin) by means of a dye-recovery spectrophotometric technique. Standardized cylindrical Class V preparations, 3 mm in diameter and 1.5 mm deep, were made on the facial surfaces of the roots of ninety extracted human maxillary and mandibular permanent canines and the teeth were restored with the recommended resin composite. The root apices were removed, Class V preparations made at the cut apices and restored with two coats of Copalite varnish and amalgam. The teeth were painted with two coats of nail varnish except for 1 mm surrounding the restorations prior to thermocycling x500 in 2% methylene blue solution. Root sections including the restorations were placed in 50% HNO3, the dye extracted and the dye concentrations determined spectrophotometrically. Standard solutions with known amounts of dye were prepared in 50% HNO3 and unrestored root sections placed in these. ML was expressed as micrograms dye/restoration and data analyzed by ANOVA and Duncan's test. The following results were obtained: (A) 3.67 +/- 2.18; (B) 2.76 +/- 1.71; (C) 2.57 +/- 0.97; (D) 2.56 +/- 2.51; (E) 1.21 +/- 0.24; (F) 0.49 +/- 0.20. Clearfil PhotoBond and Prisma Universal Bond 3 showed significantly less microleakage than other systems evaluated.

Evaluation of the Syntac bonding system.

The purpose of this in vitro study was to determine the shear bond strength [SBS] of Syntac to dentin; to determine the quantitative microleakage (ML) of Class V preparations in dentin restored with the Syntac system; and to study resin penetration into the dentin tubules by SEM. The occlusal surfaces of 30 extracted human mandibular permanent first and second molars were ground wet on 600-grit SiC to expose the superficial dentin. The teeth were embedded in brass tooth cups with cold cure acrylic resin. The Syntac Primer and the Syntac Adhesive were applied to the demarcated bonding sites as recommended by the manufacturer. Radiopaque Heliomolar was transferred to the opening in a split teflon mold in three increments, each compressed firmly and cured for 40 seconds. Fifteen of the test specimens were disassembled 60 seconds after cure [A], and the remainder 15 min after cure and the latter specimens stored in saline at 37 degrees C for 24 hours [B]. A shear load was applied at a crosshead speed of 0.5 mm/min, the SBS calculated and expressed in MPa. The data were analyzed by a two-sample t-test. Class V cavities were prepared on the facial surfaces of 15 human premolars and restored. The ML was determined quantitatively by a spectrophotometric dye recovery method and expressed as microgram dye/restoration. The mean +/- SD of the SBS in MPa were: A: 10.14 +/- 2.80; B: 15.90 +/- 2.13 and the ML 2.57 +/- 0.97 microgram dye/restoration. The SBS recorded after 24 hours storage was significantly greater than after 1 minute (P < 0.0001). The bonding resin penetrated deeply into the dentin tubules.

Phosphoric acid as a dentin etchant.

This study determined the effect of phosphoric acid (H3PO4) application to dentin on the shear bond strength (SBS) and microleakage of an experimental bonding system. Thirty human maxillary permanent first and second molars were used for the SBS evaluation. In 15 of the teeth the Dentin Conditioner was applied to dentin for 30 seconds (A), while in the remaining 15 teeth the smear layer was removed by the application of a 37% H3PO4 gel for 20 seconds (B). The Primers 1 and 2 were mixed and applied to the conditioned dentin followed by the application of the Dentin Bonding Resin prior to the placement in three increments of the Bisfil-M composite. The specimens were stored in physiological saline at 37 degrees C for 24 hours prior to applying a shear load at a crosshead speed of 0.5 mm. inch-1 in an Instron machine. Shear bond strengths were expressed in MPa. Circular Class V preparations were made on the roots of 30 maxillary permanent canines, 15 restored using the Dentin Conditioner (C) and 15 by removing the smear layer with the H3PO4 gel (D). Microleakage of the restorations was determined quantitatively by means of a spectrophotometric method. The quantitative microleakage was expressed as microgram dye/restoration. The data were analyzed by the Student t-test. The following results were obtained: A: 14.2 +/- 2.2 MPa; B: 7.2 +/- 4.2 MPa; C: 30.0 +/- 28.6 micrograms dye/restoration; (D) 10.3 +/- 8.2 micrograms dye/restoration. Removing the smear layer with H3PO4 reduced the SBS to dentin but decreased the quantitative microleakage significantly.

The effects of thermal and occlusal stresses on the microleakage of the Scotchbond 2 dentinal bonding system.

The microleakage of the Scotchbond 2 Dentinal Bonding System was evaluated under various experimental conditions. In this in vitro study, Class V restorations involving both enamel and cementum were placed on the buccal surfaces of 54 extracted human permanent canines and on the buccal and lingual surfaces of eight extracted human permanent mandibular molars. The canines were divided into three groups, each undergoing different conditions of thermocycling in 0.5% basic fuchsin or distilled water and storage time in the dye. The molars were subjected to an occlusal load of 8 MPa for 66,000 times prior to being thermocycled. There were no significant differences in microleakage of the restorations placed in the canine teeth; however, microleakage in the group of molars subjected to occlusal stresses was significantly increased. This may have been due to the increased length of the restorations placed in the molar teeth.

Extracted human versus bovine teeth in laboratory studies.

The purpose of this study was to determine the shear bond strengths and microleakage of Scotchbond 2/Silux to dentin and to evaluate resin penetration into the dentinal tubules of human and bovine teeth. The shear bond strengths (SBS) were determined on occlusal dentin of 25 human permanent molars (H) and on facial dentin of 25 bovine permanent mandibular incisors (B). The test specimens were stored in physiological saline at 37 degrees C for 24 hours prior to the application of a shear load in an Instron machine at a speed of 0.5 mm/min. Microleakage (ML) of Class V restorations placed on the facial surfaces of the roots of 15 human canines (H) and 15 bovine incisors (B) was determined quantitatively. The restored teeth were thermocycled x500 in 2% methylene blue solution, the dye extracted in 50% HNO3 and the dye concentrations determined spectrophotometrically. The resin penetration into the dentinal tubules was evaluated in the SEM. The following results were obtained: SBS (MPa): H, 6.2 +/- 2.9; B, 4.4 +/- 1.2; ML (microgram dye): H, 4.7 +/- 3.2; B, 15.9 +/- 10.5. The data were analyzed by t-test. The shear bond strength of Scotchbond 2/Silux to human dentin was significantly greater (P = 0.0096) and the microleakage significantly less (P = 0.0004) than to bovine dentin despite the fact that the restorative system penetrated more densely into bovine dentin. The use of bovine teeth instead of human teeth in these types of tests is not indicated.

Laboratory study of the Herculite XR system.

The shear bond strengths of the Herculite XR system to dentin were determined the quantitative microleakage of Class V restorations in dentin evaluated; the fluoride release from the XR-Ionomer determined, and fractured test specimens depicting various failure patterns examined in the scanning electron microscope. The shear bond strength of the XR-Ionomer to dentin was 6.6 +/- 1.7 MPa and the Herculite XR 15.4 +/- 3.7 MPa. Sixteen of the 20 Herculite XR test specimens fractured in dentin. The quantitative microleakage of Class V Herculite XR restorations in dentin was 2.22 +/- 1.94 micrograms dye which was significantly reduced to 0.91 +/- 0.63 micrograms when the XR-Ionomer was placed in the floors of the preparations. The fluoride release from the XR-Ionomer dropped sharply during the first 6 days after which it reached a plateau at approximately 0.5 microgramsF.mm-2.

Shear bond strengths of the tenure dentin bonding systems.

A third generation dentinal bonding system, Tenure Solution dentin bonding system, has recently become commercially available. The original system has been modified twice. The objectives of this in vitro study were to determine the shear bond strengths of the three systems to dentin 15 minutes after specimen preparation, after 24 hours storage in physiological saline at 37 degrees C with and without temperature cycling, and after 4 weeks storage with and without temperature cycling. The shear bond strengths decreased with duration of storage but of each storage interval temperature cycling had no adverse effect on shear bond strength.