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Effect of Different Thicknesses of Pressable Ceramic Veneers on Polymerization of Light-cured and Dual-cured Resin Cements. J Contemp Dent Pract 2015 May 01;16(5):347-52

Date

07/15/2015

Pubmed ID

26162252

Pubmed Central ID

PMC4659509

DOI

10.5005/jp-journals-10024-1688

Scopus ID

2-s2.0-84949640040 (requires institutional sign-in at Scopus site)   39 Citations

Abstract

AIM: This study evaluated the effects of ceramic veneer thicknesses on the polymerization of two different resin cements.

MATERIALS AND METHODS: A total of 80 ceramic veneer disks were fabricated by using a pressable ceramic material (e.max Press; Ivoclar Vivadent) from a Low Translucency (LT) ingot (A1 shade). These disks were divided into light-cured (LC; NX3 Nexus LC; Kerr) and dual-cured (DC; NX3 Nexus DC; Kerr) and each group was further divided into four subgroups, based on ceramic disk thickness (0.3, 0.6, 0.9, and 1.2 mm). The values of Vickers microhardness (MH) and degree of conversion (DOC) were obtained for each specimen after a 24-hour storage period. Association between ceramic thickness, resin cement type, and light intensity readings (mW/cm(2)) with respect to microhardness and degree of conversion was statistically evaluated by using analysis of variance (ANOVA).

RESULTS: For the DOC values, there was no significant difference observed among the LC resin cement subgroups, except in the 1.2 mm subgroup; only the DOC value (14.0 ± 7.4%) of 1.2 mm DC resin cement had significantly difference from that value (28.9 ± 7.5%) of 1.2 mm LC resin cement (p < 0.05). For the MH values between LC and DC resin cement groups, there was statistically significant difference (p < 0.05); overall, the MH values of LC resin cement groups demonstrated higher values than DC resin cement groups. On the other hands, among the DC resin cement subgroups, the MH values of 1.2 mm DC subgroup was significantly lower than the 0.3 mm and 0.6 mm subgroups (p < 0.05). However, among the LC subgroups, there was no statistically significant difference among them (p > 0.05).

CONCLUSION: The degree of conversion and hardness of the resin cement was unaffected with veneering thicknesses between 0.3 and 0.9 mm. However, the DC resin cement group resulted in a significantly lower DOC and MH values for the 1.2 mm subgroup.

CLINICAL SIGNIFICANCE: While clinically adequate polymerization of LC resin cement can be achieved with a maximum 1.2 mm of porcelain veneer restoration, the increase of curing time or light intensity is clinically needed for DC resin cements at the thickness of more than 0.9 mm.

Author List

Cho SH, Lopez A, Berzins DW, Prasad S, Ahn KW

Authors

Kwang Woo Ahn PhD Director, Professor in the Data Science Institute department at Medical College of Wisconsin
David Berzins BS,PhD Graduate Program Director for Dental Biomaterials in the General Dental Sciences/Dental Biomaterials department at Marquette University

MESH terms used to index this publication - Major topics in bold

Curing Lights, Dental
Dental Porcelain
Dental Veneers
Hardness
Humans
Light-Curing of Dental Adhesives
Materials Testing
Polymerization
Radiation Dosage
Resin Cements
Self-Curing of Dental Resins
Spectroscopy, Fourier Transform Infrared
Surface Properties
Temperature
Time Factors