An in vitro evaluation of microtensile bond strengths of two adhesive bonding agents to residual dentine after caries removal using three excavation techniques.
OBJECTIVE
To assess amounts of residual dentine retained after using three excavation techniques; the microtensile bond strengths (microTBS) to residual dentine, comparing etch-rinse vs. self-etching adhesives.


METHODS
42 carious molars were subdivided (N=21) dependent upon adhesive/composite system (Adper Scotchbond 1XT and Filtek Supreme vs. Filtek Silorane adhesive and composite). Dividing into three (N=7), dependent upon caries excavation technique employed (hand vs. chemo-mechanical: Carisolv gel vs. experimental enzymatic gel (SFC-V)), caries removal was assessed using visual/tactile criteria and in situ autofluorescence (AF) confocal fibre-optic micro-endoscopy (CFOME). Post-restoration/four-week hydrated storage, four 0.9 mm(2) beams per tooth underwent microTBS testing/microscopic analysis of fractured surfaces. Three cavities from each excavation group were analysed using SEM.


RESULTS
SEM revealed surface roughness with smear layer occluding tubule orifices in hand-excavated samples and a reduced, variable smear layer for both chemo-mechanical systems. CFOME AF assessment indicated hand excavation left sound dentine, Carisolv left affected dentine and SFC-V slightly under-prepared clinically. Mean microTBS values from etch-rinse samples (27 MPa (SD 3.9), hand; 22 MPa (SD 5.1), Carisolv; 26 MPa (SD 4.4), SFC-V) showed statistical differences between hand and Carisolv groups. Mean microTBS data for self-etch samples (22 MPa (SD 3.3), hand; 27 MPa (SD 6.1), Carisolv; 25 MPa (SD 4.7), SFC-V) showed significant differences between hand and Carisolv, and hand vs. SFC-V. Failure loci distribution in etch-rinse samples was between dentine-adhesive, within adhesive and within composite whereas self-etch samples exhibited failure predominantly between adhesive and composite.


CONCLUSIONS
Data indicated that all null hypotheses were disproved.
Banerjee
A
A
King's College London Dental Institute, KCL, United Kingdom. avijit.banerjee@kcl.ac.uk
Kellow
S
S
Mannocci
F
F
Cook
R J
RJ
Watson
T F
TF
D000134:Acid Etching, Dental; D000268:Adhesiveness; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003731:Dental Caries / Q000473:pathology / Q000628:therapy*; D003737:Dental Cavity Preparation / Q000295:instrumentation / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry; D003793:Dental Restoration, Permanent / Q000379:methods; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005453:Fluorescence; D018698:Glutamic Acid / Q000627:therapeutic use; D006801:Humans; D007930:Leucine / Q000627:therapeutic use; D008239:Lysine / Q000627:therapeutic use; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000473:pathology; D055100:Optical Fibers; D010434:Pepsin A / Q000627:therapeutic use; D019279:Resin Cements / Q000737:chemistry; D016369:Smear Layer; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
C119934:Carisolv; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C543062:Filtek LS Low Shrink resin; C474035:Filtek Supreme; D019279:Resin Cements; D014867:Water; D018698:Glutamic Acid; C041330:Scotchbond; D010434:Pepsin A; D007930:Leucine; D008239:Lysine