Dentine permeability and bond quality as affected by new bonding systems.
OBJECTIVE
The relationship between dentine bonding and the condition of dentine for four dentine bonding systems (All Bond 2, Clearfil Liner Bond, Scotchbond MP and XR Bond) has been examined. Different dentine conditions were evaluated and correlated with adhesion values. Dentine permeability was calculated using a hydraulic pressure apparatus working under physiological pulpal pressure (6.9 kPa), while remaining dentine thickness (RDT) was measured using pincer calipers. Scanning electron microscopic (SEM) examinations were effected to analyse dentine morphology. These evaluations were considered as an index of the condition of dentine. Shear bond strength tests were used to evaluate adhesion. Dentine samples after the bonding systems application were stored for 24 h under pulpal pressure before bond strength was tested.


RESULTS
Scanning electron microscopy examinations indicated that the application of bonding system conditioners caused the removal of smear layer, the demineralization of dentine and the formation of a layer of collapsed collagen fibrils in the intertubular and peritubular dentine. Primers were able to infiltrate the collagen fibrils. A layer of resin infiltrated/reinforced dentine (the so-called 'hybrid layer') was observed for All Bond 2, Clearfil Linear Bond and Schotchbond MP.


CONCLUSIONS
Significant correlations were observed only for XR Bond, which proved very sensitive to RDT and dentine permeability despite the presence of smear layer. The other three materials did not show any correlation with dentine conditions. By contrast they showed the highest bond values.
Prati
C
C
School of Dentistry, University of Bologna, Italy.
Ferrieri
P
P
Galloni
C
C
Mongiorgi
R
R
Davidson
C L
CL
D000134:Acid Etching, Dental; D000328:Adult; D003094:Collagen; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003736:Dental Cavity Lining; D003804:Dentin / Q000648:ultrastructure*; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008963:Molar; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements; D016369:Smear Layer; D013314:Stress, Mechanical
C074864:All-Bond system; C084544:Clearfil Linerbond System; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D011140:Polyurethanes; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C070604:XR Bond; D003094:Collagen