All ETDs from UAB

Advisory Committee Chair

John O Burgess

Advisory Committee Members

Jack E Lemons

Nathaniel C Lawson

Lance C Ramp

Amjad Javed

Document Type

Thesis

Date of Award

2015

Degree Name by School

Master of Science (MS) School of Dentistry

Abstract

Dual cured resin cements are frequently used to cement all ceramic restorations. The increased thickness and /or opacity of restorations block light transmission. In these situations, where little or no light can be transmitted through the restorations, the polymerization of the cement is in the self-cure mode. Purpose: This study measures the bond strength and mode of failure of dual cure resin cements to enamel and dentin in a self-cure mode using e.max rods. Methods: 160 extracted human molars were ground to mid-coronal dentin (N=80) or superficial enamel (N=80) and finished to 320 grit disks. Four adhesive/cement combinations - Multilink Primer A & B/Multilink Automix (MA, Ivoclar), Panavia V5 Tooth Primer/Panavia V5 Paste (PanV5, Kuraray Noritake Dental), Optibond XTR/NX3 (NX3,Kerr) and Scotchbond Universal/RelyX Ultimate (RXU,3M); were applied to enamel and dentin using a self-etch, self-cure mode. A 1mm x —1mm block of e.max (Ivoclar) was etched with 5% HF (20sec), rinsed, dried, silanated, coated with each cement and seated onto enamel or dentin. 100g of force was applied to the tooth/e.max assembly for 8 minutes. To more closely replicate the oral cavity, the experiment was repeated but specimens were fabricated by applying pressure to the e.max/tooth assembly for 10 minutes in an incubator (37°C). After 24hrs storage (at 37°C), samples were debonded at 1mm/min crosshead speed in a universal testing device. A 2-way ANOVA and Tukey post hoc analysis was performed for each material (α<0.05). Results: Panavia V5 showed significantly higher bond strengths to dentin compared to RelyX Ultimate and NX3 at both room temperature and elevated temperature. RelyX Ultimate and NX3 showed a significant increase in bond strength to dentin at elevated temperature. Bond strengths of resin cements were significantly increased at elevated temperature compared to room temperature. Conclusions: Panavia V5 showed high bond strengths to both enamel and dentin in a self-cure mode. An increase in temperature significantly affects the polymerization of dual cure resin cements in the self-cure mode. Hence this study further emphasizes the importance of performing tests that can closely replicate clinical situations.

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