Effect of Immediat Dentin Sealing on the Bonding State of Hybrid Ceramic CAD/CAM Restorative Material to Dentin

Abstract

Objectives: Lately, computer-aided design (CAD) computeraided manufacturing (CAM) systems with simplified procedures for indirect restoration have gained rapid improvements and commenced to be used in daily practice of dental clinicians. The aim of this pilot in vitro study was to analyze the bonding efficiency and observation of the failure mode of hybrid ceramic CAD/CAM block materials after termo-cycling, with different immediate dentin sealing (IDS) techniques.Materials and Methods: Eighteen freshly extracted human molars were selected, and mounted with acrylic resin, fixed the root up to 2.0 mm under the cementoenamel junction. Standardized, flat, nonretentive, midcoronal dentin surfaces were prepared. Using the stratified random sampling process, all teeth (N=18) were divided into groups of three by approximately similar sizes; afterwards, these teeth were randomly distributed into the groups 1, 2 and 3 (n = 6). The specimens from groups 2 and 3 received IDS, whereas delayed dentin sealing was carried out for specimens of control group (Group 1). For IDS materials, universal adhesive system G-Premio Bond (GC, Tokyo, Japan) and highly filled flowable resin composite G-aenial Universal Flo (GC, Tokyo, Japan) were used. All block material specimens were prepared using the cutting instrument (IsoMet 1000; Buehler, USA) and were fitted with a standardized 3x3-mm 3 cubes cutted out of a CAD/CAM block of hybrid ceramic (Cerasmart, GC; Tokyo, Japan). Dual-polymerized resin cement G-CEM Link Force (GC, Tokyo, Japan) was utilized to lute restoration materials for all groups. To test the shear bond strength (SBS) each of the specimens was placed in a jig with 90 o to the vertical plane and tested a universal testing machine (Shimadzu AG-IS; Shimadzu Corp). One-way ANOVA was used to analyze the data of the SBS. Results were evaluated statistically significant for p<0.05.Results: No statistically significant difference revealed by the statistical analysis between Group 1,2 and 3 (p=0,372). This means there is no significant difference in the sealing methods (p>0,05). Bond failure rates showed similar results in all groups, where the most frequent failure pattern detected was 'adhesive type'.Conclusions: Within the limitation of this in vitro pilot study, the following conclusion was drawn: 2 Different IDS procedures tested does not statistically (p<0.05) effect the SBS of hybrid ceramic CAD/CAM material bonded to dentin with G-CEM Link Force.

Influence of different immediate dentin sealing strategies on bond strength of indirect resin nanoceramic restorations

“…Sample size was estimated based on assuming 5% alpha error and 80% study power. The assumed mean (SD) values for the shear bond strength were 7.17 (2.09) MPa for the delayed dentin sealing (control) [32], 14.86 (3.40) MPa for immediate dentin sealing with immediate bonding [33], 14.36 (2.53) MPa for immediate dentin sealing with bonding after 2 weeks with provisional restoration, and 17.06 (4.94) MPa for immediate sealing with flowable resin composite reinforcement and bonding after 2 weeks with provisional restoration [29]. Based on difference between independent means using F test and the highest SD = 4.94 the minimum sample size was calculated to be six specimens per subgroup.…”

“…Provisional material (Telio CS onlay; Ivoclar Vivadent) was applied to the occlusal dentin surface up to the border of the metallic band and photopolymerized for 15 s followed by repolymerization from all sides after removal of the band. The specimen was then stored in artificial saliva at 37˚C for 2 weeks [2,29] until bonding.…”

“…The adhesive was applied immediately after preparation and photopolymerized for 10 s. The adhesive layer was then covered by flowable resin composite layer (Filtek Ultimate, 3M) with an average thickness 1 mm (glass microscope slide was used to obtain smooth uniform thickness) and photopolymerized for 40 s [9,29]. The composite surface was covered with glycerin gel and cured another 10 s in order to reduce the oxygen-inhibited layer.…”

“…Following the previously mentioned technique, 3 mm of the provisional material was applied to the composite surface. Then, they were stored in artificial saliva at 37˚C for 2 weeks [2,29] until bonding.…”

“…The immediate dentin sealing technique using various adhesive generations has been studied previously [1,4,[25][26][27] to address its importance; however, its effectiveness with universal adhesive systems is uncertain, as the newer systems have different characteristics from those of earlier generations [28,29]. To help clinicians decide on the best technique for bonding resin nanoceramic restorations to dentin surfaces using universal adhesives and their corresponding resin cements, various clinical scenarios and dentin-sealing strategies were simulated in this study.…”