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Updated: May 25, 2026
Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis
Published on: August 15, 2018
The effect of phosphoric acid pre-etching and thermocycling on self-etching adhesive enamel bonding
James L Sheets1, Charles W Wilcox, Wayne W Barkmeier
1Department of Prosthodontics, Creighton University School of Dentistry, Omaha, NE 68178, USA. jsheets@creighton.edu
Statement Of Problem:
When inserting a resin-bonded prosthesis, it is not known whether pumicing, rinsing, and using a self-etching primer (SE) on prepared surfaces is sufficient or whether the use of an additional conventional acid etchant is warranted due to the increased time and risk of contamination.
Purpose:
The purpose of this study was to evaluate the effects of pre-etching with phosphoric acid (PA) and thermocycling (TC) on the enamel shear bond strength (SBS) of an autopolymerizing adhesive system on ground enamel.
Material And Methods:
Human teeth were embedded in phenolic rings with methyl methacrylate resin, and their enamel surfaces were ground flat to a 600 grit surface. The teeth were then divided into 4 subsets (n=22): 1) PSN, PA pre-etch with SE, no TC; 2) PST, PA pre-etch with self-etching primer and TC; 3) SEN, self-etching primer alone, no TC; and 4) SET, self-etching primer and TC. A multifactorial study design was used to evaluate 2 factors (pre-etching with PA and TC) at 2 levels (presence or absence) by grouping different subsets. Pre-etch consisted of teeth being etched for 30 seconds with PA, rinsed, re-etched, and rinsed. Self-etching consisted of 60 seconds with ED Primer. Rods of Rexillium III, airborne-particle abraded with 50 μm aluminum oxide, were bonded to enamel surfaces with Panavia 21 OP under a 19.6 N load. Thermocycling consisted of alternating between water baths of 5 ± 2°C and 55 ± 2°C for 5000 cycles. Shear bond strength (SBS) was determined by loading the specimens to failure at a crosshead speed of 1 mm/min. Mean values were analyzed with a 2-way ANOVA (factors were surface treatment and TC) at α=.05.
Results:
Pre-etching with phosphoric acid showed greater SBS to enamel (P=.028) than the self-etching primer alone. Thermocycling did not have a significant effect (P=.424).
Conclusions:
There was a significant difference in SBS between pre-etching enamel surfaces with phosphoric acid in addition to the self-etching primer and using the self-etching primer exclusively. Thermocycling did not significantly affect SBS.
