Influence of water flow rate on shear bond strength of resin composite to Er:YAG cavity preparation.
OBJECTIVE
To evaluate in vitro the influence of water flow rate on shear bond strength of a resin composite to enamel and dentin after Er:YAG cavity preparation.


METHODS
Ten bovine incisors were selected and roots removed. Crowns were sectioned in four pieces, resulting in 40 samples that were individually embedded in polyester resin (n = 10), and ground to plane the enamel and expose the dentin. The bonding site was delimited and samples were randomly assigned according to cavity preparation: (1) Er:YAG/1.0 mL/minute; (2) Er:YAG/1.5 mL/minute; (3) Er:YAG/2.0 mL/minute and (4) High speed handpiece/bur (control group). Samples were fixed to a metallic device, where composite resin cylinders were prepared. Subsequently, they were stored for 24 hours and subjected to a shear bond strength test (500N at 0.5 mm/minute).


RESULTS
Means (MPa) were: enamel: 1: 12.8; 2: 16.8; 3: 17.5; 4: 36.0 and Dentin: 1: 13.6; 2: 18.7; 3: 12.1; 4: 21.3. Data were submitted to ANOVA and Tukey's test. Adhesion to enamel was more efficient than for dentin. The cavities prepared with conventional bur (control) presented higher statistically significant bond strength values (P < 0.05) than for Er:YAG laser for both enamel and dentin. No significant differences were observed between water flow rates employed during enamel ablation. For dentin, the shear bond strength of 2.0 mL/minute water flow rate was lower than for 1.5 mL/minute and 1.0 mL/minute rates. The Er:YAG laser adversely affected shear bond strength of resin composite to both enamel and dentin, regardless of the water flow rate used.
Colucci
Vivian
V
Department of Operative Dentistry, School of Dentistry, University of São Paulo, Ribeirão Preto, SP, Brazil.
Lucisano
Marília Pacífico
MP
do Amaral
Flávia Lucisano Botelho
FL
Pécora
Jesus Djalma
JD
Palma-Dibb
Regina Guenka
RG
Corona
Silmara Aparecida Milori
SA
D000134:Acid Etching, Dental; D000268:Adhesiveness; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000295:instrumentation / Q000379:methods*; D003743:Dental Enamel / Q000648:ultrastructure; D003754:Dental High-Speed Equipment; D003764:Dental Materials / Q000737:chemistry*; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D053844:Lasers, Solid-State; D011897:Random Allocation; D033081:Shear Strength; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry*
D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; C115612:single bond; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate