Bond Strength Of Resin Research Articles

“Effect of three vitamin antioxidants on reversal of shear bond strength of bleached enamel: An in-vitro Study.”

ABSTRACT
 Aims and objectives: To evaluate the effect of Sodium ascorbate, Alpha-tocoferol and Beta-carotene vitamins antioxidant on reversing the bond strength between resin composite and bleached enamel surface.
 Materials and methods: The study focussed on use of three vitamin antioxidants. All the groups in the study were subjected to bleaching containing 35% Hydrogen peroxide. Resin restoration were done after 1 week and immediately after bleaching without any antioxidant in Group 1 and 2 respectively. While in Group 3, 4 and 5, following bleaching treatment, samples were exposed to Beta-carotene gel, Sodium Ascorbate solution and Alpha-tocoferol gel respectively for 10 minutes, before resin restoration was done. Specimens were then subjected to Universal Testing Machine. The results were statistically analysed using ANOVA test and Tukey Honest Significant Difference (HSD) test, to comparatively analyse statistical differences between the groups.
 Results: The mean shear bond strength values of Group 4 (Sodium Ascorbate solution) showed significantly high bond strengths than Groups 3 (Beta-carotene gel) and 5 (Alpha-tocoferol gel).
 Conclusion: Treatment of bleached enamel with Sodium ascorbate and Alpha tocoferol antioxidants has significantly improved the shear bond strength of composite resin to enamel.
 Keywords: alpha-Tocopherol, Antioxidants, Ascorbic Acid, beta Carotene

Assessment of Hardness, Flexural Modulus, and Bond Strength of Acrylic Denture bases Fabricated by 3D Digital Methods

Abstract: Objectives: The inferior mechanical properties and the clinical failure of the denture bases could be related to their processing technique and the type of resin used during fabrication. Therefore, this study aimed to evaluate and compare the effect of the processing technique on the hardness, flexural modulus, and bond strength of the different denture base resins. Materials and Methods: Three processing techniques were used in the present study to fabricate the tested samples; compression-molded fabrication method “control group”, and two different three-dimensional (3D) fabrication methods (CAD/CAM milled “subtractive”, and 3D printed “additive”). The samples used in this study fabricated with different dimensions according to the type of test (hardness, flexural modulus, and shear bond strength). Results: The results of hardness and flexural modulus revealed that; the CAD/CAM milled samples showed statistically significant higher hardness and flexural modulus values followed by the conventional compression molded and 3D printed respectively. While the results of shear bond strength showed no statistically significant difference among the three different processing methods. Conclusion: the processing technology has a significant effect on the hardness and flexural modulus of the material. While there is no effect to the fabrication technique on the teeth bond strength.

Comparison of shear bond strength of resin cements to IPS empress 2 ceramic under four surface conditioning treatments: An in vitro study

1. To evaluate and compare the shear bond strength of four resin cements to IPS Empress 2 ceramic under four surface treatment conditions. 2. To compare the shear bond strength of light cure and Dual cure resin cements to IPS Empress 2 ceramic under four surface treatment conditions. Materials and Methods: The resin cements used in the study were Rely XTM veneer cement - light cure, Variolink II light cure and dual cure and Calibra dual care. The ceramic surface treatments were 1. Abrasion with 600 grit silicone carbide paper 2. Etching with 9.5% hydrofluoric acid for four minutes 3. Treating with silane for one minute and 4. Combination of etching and silane application. The ceramic used in the study was IPS Empress 2. Results: One-way ANOVA of shear bond strength of resin cements showed hydrofluoric acid etching followed by silane application produced bond strength in the highest statistical group and there were no significant differences among the four cements when hydrofluoric acid etching was followed by silane application. One way ANOVA of shear bond strength of light cure and dual cure resin cements showed that the dual cure resin cements showed higher bond strength. Conclusion: Within the limitation of the study hydrofluoric acid etching followed by silane produced the best bond with the four resin cements. The dual cure resin cements produced higher bonds strength to ceramic.

The Role of Epigallocathecin-3-gallate as an Antioxidant After Dental Bleaching on Shear Bond Strength of Composite Resin Restoration

Background: Tooth discoloration can be treated with dental bleaching using Hydrogen peroxide (H2O2). Dental bleaching may interfere with the shear bond strength of composite resins because the remaining free radicals can affect bonding polymerization. Epigallocatcehin-3-gallate (EGCG) as an antioxidant can neutralize the free radicals produced during bleaching process. Purpose: Analyze the role of EGCG antioxidants in increasing the shear bond strength of composite resin after bleaching.. Reviews: Of the seven journals included in this literature review, six journals reported significant difference, and one journal noted no significant difference in the shear bond strength of composite resin following the EGCG application. Conclusion: The use of EGCG can increase the shear bond strength value of post-bleaching composite resin restorations.

Pomegranate (Punica granatum L.) gel extract as an antioxidant on the shear bond strength of a resin composite post-bleaching application with 40% hydrogen peroxide

Background: Tooth discoloration can be treated with tooth bleaching. Bleaching using 40% hydrogen peroxide can reduce the shear bond strength of resin composite because there are free radicals on the tooth surface, so it can delay the restoration. The application of antioxidants can eliminate free radicals after the bleaching procedure and increase the shear bond strength of the composite resin. The common antioxidants are ascorbic acid and natural ingredients, such as pomegranate (Punica granatum L.). Purpose: To determine the effect of pomegranate extract gel on the shear bond strength of composite resin after 40% hydrogen peroxide bleaching application. Methods: This research used 32 maxillary first premolars that were divided into four groups. The samples were bleached, then the labial was prepared and antioxidant gel was applied: group P1 pomegranate gel extract of 5%, group P2 pomegranate gel extract of 10%, group K1 positive control ascorbic acid gel of 10% and group K2 as the negative control. The samples were restored with a nanohybrid composite resin. The shear bond strength was tested using a universal testing machine. The data were tested using a one-way ANOVA followed by a post-hoc LSD test. Results: The pomegranate gel extract increased the shear bond strength of the composite resin after the bleaching procedure of 40% hydrogen peroxide compared with the ascorbic acid gel group and the negative control group. The one-way ANOVA test showed a significant difference (p<0.05). The post-hoc LSD test showed significant differences between the treatment and negative control groups (p<0.05). Conclusion: The pomegranate gel extract as an antioxidant increased the shear bond strength of the composite resin restoration after the 40% hydrogen peroxide bleaching application.

The Effects of Different Antioxidant Agents on the Microtensile Bond Strength of Composite Resin to Bleached Enamel

Objective: The objective of this in vitro study is to examine the effect of antioxidants on the bonding strength of composite resin to bleached enamel. Materials and Methods: One hundred twenty non decay teeth were used in this study. Specimens were cut from the enamel cement junction. Then the specimens were randomly assigned into two groups-office bleaching and home bleaching. Bleaching antioxidants were applied to the first 12 subgroups. The specimens in the remaining 12 groups were kept in artificial saliva for 14 days and antioxidants were applied. Composite resin restoration was applied to all specimens. A cutting device was employed to obtain six specimens (0.9mm) from each tooth, and the microtensile bond strength (μTBS) test was performed. Data were analyzed using one-way ANOVA, the paired t-test, and Duncan’s post hoc test (p=0.05). Results: In office bleaching specimens, immediate antioxidant application increased the μTBS values (p<0.05). Comparisons of the antioxidants individually revealed that bonding values increased after two weeks in specimens subjected to antioxidant application (p<0.05). In office bleaching specimens, immediate antioxidant application increased the μTBS values (p>0.05). Mean μTBS values in the groups to which antioxidants were applied two weeks after home bleaching were higher than those in the groups in which antioxidants were applied immediately. Conclusion: The use of antioxidants after bleaching may increase the MTBS value. The clinician should take this into account especially in immediate restoration applications after bleaching.

In vitro effect of Er,Cr:YSGG laser on microtensile bond strength of composite resin to dentin using two different bonding systems

In vitro effect of Er,Cr:YSGG laser on microtensile bond strength of composite resin to dentin using two different bonding systems

THE EFFECT OF AIR DRYING TIME ON BONDING (SELF ETCH) WITH ETHANOL AS A SOLVENT TO THE SHEAR BOND STRENGTH OF BIOACTIVE COMPOSITE RESIN

ABSTRACTBackground: Surface resistance between composite resin and dentin is currently one of the problems of restorative materials. Failure ofcomposite resin are still being reported in clinical studies with failure rates ranging between 5-45% based on observations for 5-17 years. Bioactive composite resin is a new type of composite resin that has mechanical and chemical properties similiar to teeth. The use of resins, bonding materials, drying time of the solvent, and type of solvent also affect the shear bond strength Purpose: The purpose of this study was to analyze the effect of air drying time bonding (self-etch) with ethanol as a solvent on the shear bond strength of bioactive composite resins. Methods: This study used 32 non-carious maxillary premolar teeth that were fixed using acrylic resin. Fiber glass with a diameter of 3 mm and thickness of 3 mm were fixed to dentin surface and applied using bioactive composite resin were divided into 4 treatment group, i.e. the group without air drying, 20 s, 40 s, and 60 s. Shear bond strength test using Universal Testing Machine. Results: One Way Anova and Post Hoc Bonferroni test showed significant differences with p=0,002 (p<0,05). The average shear bond strength value of the lowest bioactive composite resin in the group bonding without air drying with a value of 6.381 ± 2.818 MPa and the highest shear bond strength value of the bioactive composite resin in the 60 seconds bonding air drying group with a value of 11.873 ± 2.931 MPa. Conclusion: The air drying time of the bonding affects the shear bond strength of the bioactive composite resin.Keywords: Air drying time, bioactive composite resin, bonding, ethanol, shear bond strength.

Effect of epigallocatechin-3-gallate and thermal cycling on the bond strength of resin cements to the root dentin.

This study evaluated the effect of epigallocatechin-3-gallate (EGCG) solution and thermal cycling on the bond strength (BS) of fiber posts to the root dentin using two different resin cements (conventional or self-adhesive). One hundred and forty-four bovine roots were endodontically treated. After post space preparation, specimens were randomly divided into six groups (n = 24) according to dentin pretreatment [distilled water, 0.05% EGCG solution or 2% chlorhexidine (CHX) solution] and resin luting agent used for fiber post cementation (RelyX ARC or RelyX U200-3 M ESPE). Then, the samples were separated into two subgroups (n = 12): storage in distilled water at 37 °C for 24 h and thermal cycling (5 °C/55 °C, dwell time 30 s-12,000 cycles) during 6 months. After that, the specimens were subjected to the pull-out BS test (Universal Testing Machine-0.5 mm/min) and the failures pattern was analyzed in a stereomicroscope. According to the BS results (three-way ANOVA, Tukey's test, α = 0.05), the highest values were reported in the group EGCG + RelyX U200, showing significant statistical differences compared to all the other experimental groups. For Control and CHX groups BS values, there was no significant difference (p > .05) between the resin cements. For conventional resin cement, there was no significant difference among treatment solutions (p > .05). The thermal cycling did not influence the BS results (p > .05). As reported by the failure mode analysis, adhesive failure was predominant in all groups. EGCG solution improved the bond strength of self-adhesive resin cement to root dentin.

Effect of different tooth whitening systems in combination with buffering and antioxidant agents on the shear bond strength of composite resin – An invitro study

Aim: The purpose of this in-vitro study was to evaluate the effect of tooth whitening systems on bond strength of composite resin. Material and Methods:One hundred and twenty maxillary central incisors (n=120) were divided into two groups based on the tooth whitening procedure used. Group 1: Bleaching (Pola Office, USA), Group 2: Micro abrasion (Opalustre, Australia). The samples subdivided into three groups depending on the surface treatments. Group A: Control (no surface treatment), Group B: Buffering agent (Sodium bicarbonate), Group C: buffering agent followed by Antioxidant (Sodium ascorbate). After the surface treatments, the groups were further subdivided into two (I & II), based on the storage period in artificial saliva before the composite restoration.Composite resin was bonded to the labial surface of the teeth perpendicular to the long axis and the specimens were stored in artificial saliva for 24 hours. The samples were then subjected to shear bond strength test under the Universal testing machine. Statistical analysis: The results obtained were subjected to statistical analysis using a two-way ANOVA test, independent t-test, and Tukeys multiple post hoc tests. The p value was set <0.05. Results:The results obtained have shown that out of all the groups, Group 1 with CII showed higher bond strength and Group 1 with AI shower lower values of bond strength. Among the groups, all the groups surface treated with buffering agent and antioxidant showed higher values of bond strength than control and buffering agent groups. The delay in time period showed significant difference in Group 1 than in Group 2. Conclusions: Within the limitations of the current study, bleaching and micro abrasion followed by surface treatment using buffering agent followed by antioxidant application showed improved bond strength than the other groups after bleaching. Key Words: Bleaching, Microabrasion, Buffering agent, Antioxidant, Bond strength.

Different Etching Times of a One-step Ceramic Primer: Effect on the Resin Bond Strength Durability to a CAD/CAM Lithium-Disilicate Glass-Ceramic.

To evaluate the effect of different etching times of a self-etching ceramic primer on the microshear bond strength (µSBS) and topographic surface pattern of a lithium-disilicate glass-ceramic. Ceramic slices were subjected to an in-lab simulation of CAD/CAM milling and randomly allocated to 10 groups (n = 35) considering two factors: "surface treatment" in 5 levels - one control group (5% hydrofluoric acid + silane application [HF5+SIL]), and 4 experimental groups using ceramic etching/primer (Monobond Etch & Prime, E&P) with different passive application times (40 s, 2 min, 5 min, or 10 min); and "aging" factor in 2 levels - short-term (after 24 h), or long-term (storage for 180 days + 12,000 thermal cycles). Composite cement cylinders were built and µSBS tests were run in a universal testing machine. The failure patterns were categorized, and complementary analyses with SEM and Atomic Force Microscopy (AFM) were performed. The groups showed statistically similar bond strengths in the short term (range 22.4 to 25.1 MPa). However, only the E&P 20s+40s (19.3 MPa) and E&P 20s+5min (21.5 MPa) groups maintained stable bond strength in the long term, and HF5+SIL (17.1 MPa) presented statistically significantly lower values than did E&P 20s+5min. The failure pattern was predominantly adhesive. The increased application time of the ceramic primer promoted greater dissolution of the glass matrix; thus, the E&P 20s+10min group presented the most complex surface characteristics in the fractal dimension analysis. The self-etching ceramic primer can be used as an alternative to classical conditioning with HF plus silane, promoting stable bond strength for etching times of 40 s or 5 min of passive application.

Effect of Root Canal Filling Materials and Pretreatment with Solvents on the Shear Bond Strength of Composite Resin with Primary Tooth Dentin.

Aim Root canal filling materials have the tendency to inhibit adhesion of resin-based composites. This study was aimed at evaluating the effect of root canal filling materials and their solvents on the shear bond strength (SBS) of resin composite with the primary tooth dentin. Methods and Materials Seventy-two intact anterior primary teeth were selected. Smooth dentinal surfaces were prepared to a minimum diameter of 3 mm and thickness of 1.5–2.0 mm. The samples were equally divided into six groups (n = 12). In group 1: control group, no root filling material; in group 2: Metapex, no solvent; in group 3: Metapex+ethanol solvent; in group 4: ZOE, no solvent; in group 5: ZOE+ethanol solvent; and in group 6: ZOE+orange oil solvent were applied. Then, dentin surfaces were etched, and composite restorations were placed and cured. The specimens were stored in distilled water at 37°C for 24 hours. SBS values were determined using a universal testing machine. Results The SBS values of composite to dentin in groups 2 and 4 were significantly lower than those in the control group (P < 0.001). Cleansing of the specimens with 96% ethanol after removal of Metapex significantly increased the composite-dentin bond (P < 0.001). Applying ZOE, only orange oil solvent significantly increased the SBS of the composite to the primary tooth dentin (P = 0.01). Conclusion To reduce the negative effects of endodontic root filling materials on the SBS of composite and primary tooth dentin, ethanol is a suitable solvent when Metapex is used, while orange oil might be a better choice than ethanol when applying ZOE.

Comparative evaluation of bond strength of denture base resin to acrylic resin teeth following different surface treatments: An In vitro study

Acrylic resin denture base material has been available to the dental profession for over 60 years, and although materials with superior properties have been on the market for some time, it still remains the most popular choice of clinicians. The requirement of the simple processing equipment and low cost of the fabrication process are the reasons for its continued popularity. However, debonding of acrylic teeth from denture base resins remains a problem for both patients and clinicians. The failure rate of acrylic dentures resulting from fracture has been reported to be unacceptably high, with the most prevalent type of failure documented being debonding or fractures of the teeth A series of studies have attempted to determine the quality of denture tooth bonding produced by commonly employed dental laboratory conditions. The present study was under taken to evaluate and compare the effects of chemical and mechanical treatment of the ridge lap surface of acrylic teeth on the bond strength of acrylic resin teeth to denture base resins.

The Bond Strength of Universal Adhesives with Different Acidities to Calcium Silicate-Based Materials

Objective: To compare the micro-shear bond strengths of 3 different universal adhesives to 2 different calcium silicate-based materials. Methods: A hole was prepared in the center of the top surfaces of 60 cylindrical acrylic blocks, and the blocks were randomly divided into 2 groups (n=30) according to biomaterial filling; NeoMTA Plus (Avalon Biomed Inc. Bradenton, FL, USA) and ProRoot MTA (Dentsply Tulsa, Tulsa, OK, USA). Biomaterials were prepared according to the manufacturers’ instructions. The sample surfaces were flattened after the initial setting, and the samples were incubated for 24h at 37°C. After placing the biomaterials in the prepared holes, the specimens were randomly divided into 3 subgroups (n=10) according to adhesive; G-Premio Bond (GC Corp., Tokyo, Japan), All-Bond Universal (Bisco, Inc., Schaumburg, IL, USA) and Single Bond Universal (3M ESPE, St Paul, MN, USA). Adhesives were applied to the specimens and polymerized. A micro-hybrid composite resin (Filtek Z250, 3M ESPE, MN, USA) was then placed on the specimen surfaces and polymerized. Micro-shear bond strengths were tested using a universal testing device (LRX, Lloyd Instruments, Farnham, UK). A Shapiro-Wilk test confirmed normal distribution, and 2-way ANOVA was used for statistical analysis. Result: No significant differences were found in the shear bond strengths of any of the tested adhesives to either of the calcium silicate-based materials (p&amp;gt;0.05). Conclusion: The results indicate that the acidity of a universal adhesive does not affect the bond strength of composite resin to calcium silicate-based materials.

Effect of different cleaning methods on resin bond strength of contaminated monolithic zirconia

The present study evaluated the effects of cleaning methods on resin bond strength to contaminated monolithic zirconia. A total of 180 bar-shaped monolithic zirconia specimens (12 mm × 4 mm × 1.2 mm) were abraded with aluminum oxide and divided into nine groups (n = 10). The control group (Cnt) comprised non-contaminated or cleaned monolithic zirconia specimens. Half of the remaining samples were contaminated with saliva (S) and the other half with a silicone disclosing agent (F; Fit checker). The bonding surfaces of the specimens were cleaned with water (Sw and Fw), 0.5% sodium hypochlorite (NaOCl) solution (Sh and Fh), 37% phosphoric acid gel (Sa and Fa), or plasma treatment (Sp and Fp). The bars were luted end-to-end on the bonding surfaces using a self-adhesive resin cement with a custom-made stainless-steel mold. After 72 h of water storage, the bond strength was measured using a four-point bending test. Data were analyzed using two-way ANOVA and Tukey’s test. The Cnt group showed the highest four-point bending strength (p < .05). There were no significant differences among the groups subjected to the cleaning methods, except the NaOCl groups (p > .05). These findings indicate that the cleaning protocol for saliva- or fit checker-contaminated monolithic zirconia ceramics must be taken into account to ensure zirconia–resin cement bond strength resistance. The plasma treatment that an alternative cleaning method for decontamination did not affect the bond strength between monolithic zirconia and resin cement.

Microshear Bond Strength and Microleakage of a Restorative Composite Resin with Salivary Contamination at Different Time Intervals

Introduction : Saliva contamination is an inevitable and common challenge in the field of restorative dentistry. Recognizing and considering the key time of isolation is an effective strategy to prevent the deleterious effects of salivary contamination. The purpose of this study was to evaluate the effect of salivary contamination in the course of light curing on microshear bond strength and microleakage of a restorative composite resin. Methods: 140 human third molars were divided into seven groups each containing 10 samples for measuring the microleakage and the microshear bond strength. The specimen of each group was contaminated with human saliva at a certain time, while group1 was contaminated in prior to light curing. The samples in groups 2 to 7 were contaminated with saliva at 2, 5, 10, 15, and 20 s after the start of light curing, respectively. The specimens of group7 were light cured and contaminated afterwards with human saliva. Results: According to the gathered results, the time of saliva contamination had significant negative effects on the microshear bond strength to the dentin and enamel in the course of light curing throughout the first 2s and 5s, respectively. It was indicated by the microleacage test that the saliva contamination in the first 2s, 5s, and 10s during light curing had a higher microleakage than the other times. Conclusion: In conclusion, during light curing of the composite resin, the first 10s was high sensitive to saliva contamination and therefore the isolation is very important in this time.

Effect of plasma sizing on basalt fibers adhesion with wood-working resins

Basalt fabric with manufacturer-made silane sizing was additionally treated by propane-butane enriched atmospheric pressure nitrogen plasma for 15 and 30 s. The wetting improvement of treated fabric was demonstrated by faster soaking of K2CO3 solution. FTIR and XPS analyses confirmed the presence of new nitrogen-containing chemical groups. The impact on adhesion was investigated via a shear strength test of basalt fabric inlay between two beech wooden boards. A short 15 s long treatment led to almost 50% increase in melamine-urea formaldehyde (MUF), polyvinyl acetate (PVAC) and epoxy resin bond strength. Phenol-resorcinol formaldehyde (PRF) needed longer treatment to achieve a bond strength of 11.2 MPa. Only the polyurethane (PUR) showed reduced adhesion to plasma-treated fibers. However, from all tested resins, PUR exhibited the highest bond strength (15.7 MPa) with untreated basalt fabric. The SEM of tested specimens confirmed the changes in the mechanical adherence of resins to plasma treated fibers. Based on these results, PRF and PUR seem to be the most suitable polymers for basalt fibers reinforcement of structural wood-based materials.

Comparative Study of Chemical and Mechanical Surface Treatment Effects on The Shear Bond Strength of Polyether-Ether-Ketone to Veneering Resin.

To assess the shear bond strength of composite resin to polyether ether ketone (PEEK) after mechanical and chemical surface treatments. A total of 48 PEEK discs were fabricated and divided equally into four surface treatment groups (n = 12 each): (1) airborne particle abrasion with 50-μm alumina particles at 2 MPa pressure for 10 seconds; (2) 98% sulfuric acid etching for 1 minute; (3) airborne particle abrasion and sulfuric acid etching; and (4) no surface treatment. Specimens were conditioned, then Gradia composite veneer (GC) was applied to the PEEK surfaces and polymerized. Bond strength was measured with shear bond test using a universal testing machine. One-way analysis of variance and Tukey post hoc tests were applied for statistical analysis. The mean shear bond strength values of the sulfuric acid-etched group were higher than that of the airborne particle abrasion + acid etching, airborne particle abrasion, and control groups (P < .05). Mean shear bond strength values for the airborne particle abrasion + acid etching samples were higher than for the control and airborne particle abrasion groups (P < .05). There was no significant difference between the samples treated with airborne particle abrasion and the control group.

Shear bond strength of acid and laser conditioned enamel and dentine to composite resin restorations: An in vitro study.

ObjectiveTo compare the shear bond strength of enamel or dentin conditioned with either Er,Cr:YSGG (erbium, chromium: yttrium–scandium–gallium–garnet) laser or phosphoric acid to composite resin restoration.Material and methodsForty posterior human extracted teeth were used. After mesiodistal sectioning of the teeth crowns, the samples were randomly divided into two groups—in the first group (E), bonding was performed on the enamel after roughening and in the second group (D), the enamel was removed and bonding was performed on the dentin. These groups were further randomly divided into two subgroups according to the type of etching (n = 20 each). In the acid‐etched groups (EA and DA), the surfaces were etched with 37% phosphoric acid. In the laser‐conditioned groups (EL and DL), the surfaces were conditioned with Er,Cr:YSGG laser. Total‐etch adhesive system was used to bond all the 80 specimens resin composite. The composite was vertically light‐cured, and the specimens were subjected to a shear bond strength test. Modes of bond failure were determined with a stereomicroscope.ResultsThe highest shear bond strength was observed for the DA group (16.25 ± 1.10 MPa, p < 0.0001), whereas the lowest was observed for the DL group (8.56 ± 0.67 MPa). The adhesive failure mode was the most frequently observed in all groups.ConclusionsThe shear bond strength of composite resin bonded to enamel and dentin etched with phosphoric acid was higher than when conditioned with Er,Cr:YSGG laser. Thus, laser conditioning is not recommended.

Shear bond strength of bio-active cement versus self-adhesive resin cement with enamel and dentin when bonded to zirconia in wet and dry conditions (in-vitro study)

ACTIVA bio-active cement is resin-modified glass-ionomer cement that was introduced for re-mineralizing of the disintegrated joint. Due to the lack of data about this bioactive cement, this study evaluated the shear bond strength of bioactive cement and self-adhesive resin cements to tooth substrate (enamel and dentin), in wet and dry conditions when bonded to zirconia. In this study, 40 extracted mandibular molars caries-free were collected. Each tooth was cut by diamond disk (bucco-lingual section) to expose the dentin and enamel. Teeth were randomly divided into two groups enamel and dentin (n=20). Each group was further divided into two subgroups; wet and dry samples (n=10). Each subgroup was divided according to the cement used, into resin cement or bioactive cement (n=5) and bonded to zirconia. Shear bond strength was determined, after thermo-cycling. Statistical analysis of the results showed that there was no statistically significant difference between shear bond strength of the two cement types either with wet enamel or dentin. With both cements, enamel showed statistically significantly higher mean shear bond strength than dentin. It was concluded that, both cements showed comparable results with significant superiority to the self-adhesive resin cement.