Direct dentin bonding technique sensitivity when using air/suction drying steps.
BACKGROUND
Moisture control before and after application of the primer/adhesive components of etch-and-rinse dentin bonding agents is usually achieved using a stream of air delivered by an air syringe. Suction drying with a suction tip is a common alternative for moisture control, but data about the use of suction drying instead of the air syringe is scarce or nonexistent.


OBJECTIVE
The purpose of this study was to compare the dentin microtensile bond strength (MTBS) using either the air syringe or the suction tip to control the amount of moisture.


METHODS
Fifteen freshly extracted human molars were divided randomly into three groups of five. A three-step etch-and-rinse dentin bonding agent (OptiBond FL) was used. Group 1 was the control group and utilized air drying alone (with an air syringe) during the placement of the dentin adhesive on the ground-flat occlusal dentin surface. Group 2 also used air drying alone, but teeth were prepared with a standardized MOD cavity. Group 3 utilized suction drying alone in the standardized MOD cavity. All teeth were restored with 1.5-mm-thick horizontal increments of composite resin (Filtek Z100). Specimens were stored in water for 24 hours, then prepared for a nontrimming MTBS test. Bond strength data were analyzed with a Kruskal-Wallis test at p < 0.05. Specimens were also evaluated for mode of fracture and interface characterization using scanning electron microscope (SEM) analysis.


RESULTS
The mean MTBSs were not statistically different from one another (p = 0.54) at 54.0 MPa (air-drying, flat dentin), 53.4 MPa (air-drying, MOD), and 49.2 MPa (suction drying, MOD). Microscopic evaluation of failure modes indicated that most failures were interfacial. Failed interfaces, when analyzed under SEM, appeared typically mixed with areas of failed adhesive resin and areas of cohesively failed dentin.


CONCLUSIONS
There are no differences in MTBS to human dentin using either the air syringe or the suction tip to control the amount of moisture. The conventional three-step dentin bonding agent used in the present study not only proved insensitive to the moisture-control method but also to the effect of increased polymerization shrinkage stress (ground-flat versus MOD preparation).


CONCLUSIONS
Although the effect of common errors on the performance of total-etch adhesives has been investigated, data about the use of suction drying instead of an air syringe is scarce or nonexistent. The present study demonstrated that both the air syringe and the suction tip can be used to control moisture when using etch-and-rinse dentin bonding agents. The conventional three-step dentin bonding agent tested, OptiBond FL, demonstrated low technique sensitivity.
Magne
Pascal
P
University of Southern California School of Dentistry, Division of Primary Oral Health Care, Los Angeles, CA 90089-7792, USA. magne@usc.edu
Mahallati
Ramin
R
Bazos
Panaghiotis
P
So
Woong-Seup
WS
D000134:Acid Etching, Dental / Q000379:methods; D000388:Air; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003737:Dental Cavity Preparation / Q000379:methods; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D003890:Desiccation / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013396:Suction / Q000295:instrumentation; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C469607:OptiBond FL; D019279:Resin Cements; C083568:Z100 composite resin; D014867:Water; D012822:Silicon Dioxide; D015040:Zirconium