Effect of Microwave Treatment on the Shear Bond Strength of Denture Tooth/Acrylic Resin

Abstract

This study investigated the effect of microwave treatment on the shear bond strength of the denture tooth to acrylic resin adhesion, when the glossy ridge laps were unmodified, abraded, grooved, or etched by monomer. Eighty specimens (n ¼ 10) were polymerized in a hot bath at 74 C for 9 hours, and deflasked after flask cooling. Specimens were soaked in 150 mL of distilled water and submitted to microwave treatment in a domestic microwave oven calibrated at 650 W for 3 minutes. Control specimens were not microwave treated. The shear bond strength test was performed in an Instron machine with a cross-speed of 1mm=minute. The ultimate fracture load value was transformed into shear bond strength as a function of the bonding area. Collected data were submitted to ANOVA and Tukey's test (a ¼ .05). Treatment by microwave energy significantly decreased (p < .05%) the shear bond strength values in all ridge lap conditions used for the denture tooth=resin adhesion.

Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin

“…In the current study, bur abrasion and grooving presented greater shear bond strength values; however, it is possible that the type of commercial tooth may have influenced these values. The results of this investigation are in agreement with those of classic studies 23,25,27,29 and with recent studies 17,18 , which evaluated the tooth/resin bond using bur retentions on the ridge lap.…”

“…In the present study, detergent was used to remove the wax from the ridge lap surface. For this reason, it is possible to presume that these results were because of ridge lap surface conditions, as shown in previous studies 17,18 and also because of the commercial type of the denture tooth.…”

“…The effect of bur abrasion on this tooth is difficult to explain; however, it is possible to speculate that the irregularities promoted by the abrasion on the flat surface of the ridge lap were not sufficient to evidence the effect of the different commercial types of tooth on the bond strength of the non‐microwaved and microwaved specimens. Additionally, this finding may also be associated with the minimal restriction caused by this rough surface to additional polymerisation shrinkage because of microwave treatment 18 , causing similar mechanical retention in the different commercial tooth types.…”

“…Pink acrylic resin (Classico Dental Products) was prepared using a ratio of 35.5 g polymer to 15 ml monomer, according to the manufacturer’s recommendations. Flasks were placed in traditional clamps following final pressing in a hydraulic press (Linea H) under a load of 1250 kgf for 5 min 18 . Eighty specimens ( n = 10) were conventionally packed, polymerised in a water bath at 74°C for 9 h in a polymerising unit (Termotron, Piracicaba, Sao Paulo, Sao Paulo, Brazil).…”

Effect of aluminium oxide particle sandblasting on the artificial tooth–resin bond

“…Under these conditions, it is possible that the artificial tooth displacement of the complete denture base might only occur due to the repeated chewing force (mechanical fatigue), accidental fall during cleaning, or by laboratories that fail to properly bond the artificial tooth and the resin 21 …”