Microtensile Bond Strength and Micromorphology of Bur-cut Enamel Using Five Adhesive Systems.
OBJECTIVE
This study compared the microtensile bond strengths (μTBS) of two etch-and-rinse (ER) (OptiBond FL [OBFL]; Prime & Bond NT [PBNT]) and three self-etching (SE) (Clearfil SE Bond [CSEB]; Xeno III [XIII]; Xeno V+ [XV+]) adhesives systems to bur-prepared human enamel considering active (AA) and passive (PA) application of the self-etching systems.


METHODS
Ninety-six enamel surfaces were prepared with a medium-grit diamond bur and randomly allocated into 8 groups to receive adhesive restorations: G1: OBFL; G2: PBNT; G3: CSEB/PA; G4: CSEB/ AA; G5: XIII/PA; G6: XIII/AA; G7: XV+/PA; G8: XV+/AA. After composite buildup, samples were sectioned to obtain a total of 279 bonded sticks (1 mm2) that were submitted to microtensile testing (μTBS; 0.5 mm/min) after 24-h water storage (37°C). Etching patterns and adhesive interfacial ultramorphology were also evaluated with confocal laser scanning (CLSM) and scanning electron microscopy (SEM). Data was analyzed with one-way ANOVA (α = 0.05). Weibull probabilistic distribution was also determined.


RESULTS
Regarding μTBS, both adhesive system and application mode yielded statistically significant differences (p < 0.05) among groups. ER adhesive systems together with CSEB/AA and XIII/PA recorded the highest and statistically similar bond strength results. XV+ presented very low bond strength values, regardless of the application mode. Among self-etching adhesives, CSEB produced significantly higher μTBS values when applied actively. Qualitative evaluation by SEM and CLSM revealed substantial differences between groups both in adhesive interfaces and enamel conditioning patterns.


CONCLUSIONS
ER and SE adhesive systems presented distinctive bond strengths to bur-cut enamel. The application mode effect was adhesive dependent. Active application improved etching patterns and resin interfaces micromorphology.
Alexandra
A
Vinagre
João
J
Ramos
Ana
A
Messias
Fernando
F
Marques
Francisco
F
Caramelo
António
A
Mata
D000134:Acid Etching, Dental / Q000379:methods; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel / Q000648:ultrastructure*; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry; D018130:Diamond / Q000737:chemistry; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D019246:Tooth Preparation / Q000295:instrumentation*; D014867:Water / Q000737:chemistry
C438313:Clearfil SE Bond; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C469607:OptiBond FL; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements; C487957:Xeno III; C575872:Xeno V; D014867:Water; D018130:Diamond