Role of hybridization on marginal leakage and bond strength.
OBJECTIVE
To evaluate whether the hybrid layer significantly contributes to the seal of adhesive Class V restorations placed in vivo and to the bond strength obtained in vitro.


METHODS
20 periodontally severely compromised anterior teeth were selected for the leakage study. In each tooth, one round 3 mm wide V-shaped cavity with a maximum depth of 2 mm was prepared on the labial surface crossing the cementum-enamel junction. The sample teeth were randomly divided into two groups of ten samples each: in Group 1, Scotchbond Multi-Purpose Plus was applied in combination with Z-100 following the manufacturer's instructions. In Group 2 the bonding procedure was the same as in Group 1, except that after the phosphoric acid treatment, the cavities were treated with 5% NaOCl for 2 min. Following a period of clinical service of 60-90 days, the teeth were extracted and processed for the leakage test.


RESULTS
At the enamel site, 30% of the samples of Group 1 and 70% of the samples of Group 2 showed dye penetration. At the dentin site, 50% of the samples of Group 1 showed leakage, while all the samples of Group 2 were severely infiltrated. Statistically significant differences between the groups both for the enamel sites (P < 0.05) and for dentin-cementum sites (P < 0.001) were found. Bond strength tests were performed on 2 mm thick dentin slides of tapered Class I cavities (n = 10 in each group). The mean bond strength value obtained from cavities treated without NaOCl was 15.23 (+/-1.40) MPa and with NaOCl treatment 20.52 (+/-1.70) MPa. Statistical analysis showed significant differences (P < 0.05) between the two groups. No hybrid layer was detected on the NaOCl-treated samples by scanning electron microscopy.
Ferrari
M
M
University of Siena, Italy. RCFD96@mclink.it
Mason
P N
PN
Vichi
A
A
Davidson
C L
CL
D000134:Acid Etching, Dental; D000704:Analysis of Variance; D004396:Coloring Agents; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification; D003739:Dental Cementum / Q000648:ultrastructure; D003743:Dental Enamel / Q000648:ultrastructure*; D003763:Dental Leakage / Q000145:classification* / Q000473:pathology; D003793:Dental Restoration, Permanent / Q000145:classification; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004311:Double-Blind Method; D005500:Follow-Up Studies; D006801:Humans; D008751:Methylene Blue; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D016877:Oxidants / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012822:Silicon Dioxide; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000737:chemistry; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013499:Surface Properties; D015040:Zirconium
D004396:Coloring Agents; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D016877:Oxidants; D010756:Phosphoric Acids; D019279:Resin Cements; C425844:Scotchbond Multi-Purpose Plus; C083568:Z100 composite resin; D012822:Silicon Dioxide; D015040:Zirconium; D012973:Sodium Hypochlorite; D008751:Methylene Blue