Tatsuo Endo

All-in-one self-etch model adhesives : HEMA-free and without phase separation

OBJECTIVE Aim of this study was to design HEMA-free all-in-one self-etch model adhesives without phase separation, and to investigate their efficiency on extracted human teeth. MATERIALS AND METHODS Compositions of adhesives in mass% (1): UDMA (25), 4-META (20), H(2)O (0, 1, 2, 5, 10, 20, 35, and 45), balance of acetone or ethanol. (2): UDMA (35), 4-META or 4-MET (28), H(2)O (0, 2, 4, 5, 6, and 8), balance of acetone. Phase separation was evaluated on samples exposed to ambient atmosphere. Conventional shear bond strengths (SBS, n=8) were determined on human enamel and dentin. Marginal adaptation (MGW, n=8) was assessed in cylindrical butt-joint dentin cavities. RESULTS Solutions (1) and (2) with 5 and 8% or less water content, respectively, showed no phase separation. SBSs on enamel were not different within the acetone- or ethanol-group and between the adhesive groups (1). Water content of adhesives (2) was a significant determinant of enamel SBSs, groups with 4-META or 4-MET were not different (p>0.05). Dentin SBSs with adhesives (1) were not different (p>0.05) within solvent groups, yet higher for acetone-dissolved adhesives (p<0.05). Dentin SBSs with adhesives (2) were different by water content and functional monomer (p<0.05). MGW for solutions (1) were smaller with acetone-dissolved than with ethanol-dissolved adhesives (p<0.001). Acetone solutions between 2 and 45% water content produced almost perfect marginal adaptation. Marginal adaptation of adhesives (2) was almost perfect at 5 through 8% water content. CONCLUSIONS Simplified HEMA-free self-etch adhesives without phase separation were prepared without compromises on bonding efficiency to enamel and dentin.

Long-Term Clinical Evaluation of Cervical Composite Resin Restorations Treated with the Self-Etch Bonding System

The purpose of this study was to evaluate the long-term periodic changes of marginal adaptation of cervical composite resin restorations. Class V saucer type cavities or cervical cavities were prepared on the labial or buccal surfaces of vital human incisors, canines, premolars and molars. A total of 124 restorations were placed to 40 patients (13 males and 27 females) by one operator. Two self-etch bonding systems were used in this study. Clinical findings of these fillings were periodically observed. In order to observe the marginal adaptation, impressions of these restorations were taken and precision replicas were made. These replicas were observed by scanning electron microscope. In the Fluoro bond group (Shofu, Kyoto, Japan) and Mega bond group (Kuraray, Okayama, Japan), maximum observation period is 4,582 days. In many cases of enamel and enamel dentin margin cavities, marginal steps were observed after 1 year. The widths of steps were extended with time. Three dislodged cases were observed in Fluoro bond group and two dislodged cases were observed in Mega bond group during 10 years.