IADR Abstract Archives

Dimensional Changes in Demineralized Dentin Matrices Following Use of HEMA-water vs.HEMA-alcohol Primers

Objectives: The durability of resin-dentin bonds seems to be related to how much resin is taken up into the interfibrillar spaces of the hybrid layer. The width of interfibrillar spaces appears to be related to how much interpeptide or interfibrillar hydrogen bonding is permitted to form (Pashley et al., J Biomed Mater Res 56: 273, 2001). The purpose of this study was to test the null hypotheses that there are no differences in the ability of 35% HEMA/65% solvent primers to expand dried dentine matrices or in their shrinkage following evaporation of the solvents. Methods: Dentine discs 0.2 mm-thick were prepared from mid-coronal dentine or extracted unerupted human third molars. After complete demineralization in 37% phosphoric acid, the specimens were placed in the well of an LVDT instrument which measures changes in the matrix expansion over-time following primer application and in matrix shrinkage following evaporation of solvents. Results:

Primer Composition	Expansion	Shrinkage after evaporation
35% HEMA-water	96 ± 18% (7)^a	86 ± 6% (7)^A
35% HEMA-MeOH	53 ± 12% (7)^b	29 ± 30% (7)^B
35% HEMA-EtoH	39 ± 19% (7)^b	48 ± 29% (7)^B
35% HEMA-Propanol	3 ± 3% (7)^c	0 ± 0% (7)^C

Groups identified by different letters are significantly different (p<0.05). Values are mean ± SD (N) percent of water-treated controls. The degree of re-expansion after the application of the primers to the dried dentin was found to be highest using the HEMA-water primer, followed by HEMA-methanol, HEMA-ethanol, with the HEMA-propanol primer producing no expansion. However, when the solvents were evaporated, the HEMA-water treated specimens shrank the most, the HEMA-ethanol treated specimens shrank an intermediate amount and the HEMA-methanol treated specimens shrank the least. Conclusions: The net result of expansion minus shrinkage produced by evaporation determines how much HEMA remains in the hybrid layer just prior to polymerization.

Division: AADR/CADR Annual Meeting
Meeting: 2003 AADR/CADR Annual Meeting (San Antonio, Texas)
Location: San Antonio, Texas
Year: 2003
Final Presentation ID: 110
Abstract Category|Abstract Category(s): Dental Materials: I - Adhesion-Composite Bond Strength

Authors

Eddleston, Caroline ( University of Bristol, Bristol, N/A, United Kingdom )

Hindle, Anna ( University of Bristol, Bristol, N/A, United Kingdom )

Agee, Kelli ( Medical College of Georgia, Augusta, GA, USA )

Carvalho, Ricardo Marins ( University of São Paulo, Bauru,SP, N/A, Brazil )

Tay, Franklin R ( The University of Hong Kong, Hong Kong, N/A, China )

Pashley, David H. ( Medical College of Georgia, Augusta, GA, USA )

SESSION INFORMATION

Oral
Technical and Surface-conditioning Effects on Adhesion
03/13/2003