Shear Bond Strength Of Adhesives Research Articles

Shear bond strength between dental adhesive systems and an experimental niobium-based implant material

This study aimed to investigate adhesive shear bond strength (SBS) on an ultrafine-grained niobium alloy (UFG-Nb) that is a potential dental implant material. SBS of three adhesive systems combined with three composites to UFG-Nb was compared to corresponding SBS to Ti-6Al-4V and to zirconia. Specimens of the substrates UFG-Nb, Ti-6Al-4V and zirconia with plane surfaces were sandblasted with Al2O3, cleaned and dried. Three adhesive systems (Futurabond U, Futurabond M + , Futurabond M + DCA; all VOCO GmbH, Cuxhaven, Germany) were applied each on specimens of each substrate and light cured. One composite (BifixSE, BifixQM, GrandioSO; all VOCO GmbH) was applied and light cured resulting in 27 groups (n = 10) for all substrate-adhesive-composite-combinations. SBS was measured after 24 h of storage. To simulate aging equally prepared specimens underwent 5000 thermocycles before SBS measurement. There was no significant difference in SBS within the non-aged groups. Among the artificially aged groups, GrandioSO-groups showed a greater variance of SBS than the other composites. All significant differences of corresponding UFG-Nb-, Ti-6Al-4V- and zirconia-groups with same adhesive-composite-combination (ACC) were observed between UFG-Nb and zirconia or Ti-6Al-4V and zirconia but never between the two metallic substrates. The similarity between these materials might show in their adhesive bonding behavior. As there were no differences comparing corresponding groups prior to and after artificial aging, it can be concluded that aging does not affect SBS to UFG-Nb, Ti-6Al-4V and zirconia using the tested ACCs. Adhesive bonding of established ACCs to UFG-Nb is possible resulting in SBS comparable to those on Ti-6Al-4V and zirconia surfaces.Graphical

Comparison of Shear Bond Strength of Adhesives to Enamel: An In Vitro Study

Comparison of Shear Bond Strength of Adhesives to Enamel: An In Vitro Study

Shear Bond Strength of Adhesives Placed following Selective Removal of Red-Fluorescing Carious Dentine in vitro

Red-fluorescing dentine indicates bacterial contamination [Caries Res 2002; 36: 315–319]. We investigated effect of removal of red fluorescent dentine caries on shear bond strength and fracture mode of 4 adhesive approaches. Sixty-five carious teeth and 50 noncarious controls were distributed into 4 groups: Clearfil™ self-etch (CSE), OptiBond™ FL total etch (OTE), Scotchbond™ Universal total etch (STE) and self-etch (SSE). Samples were excited at 405 nm and viewed through 530 nm filter. Carious samples were ground flat exposing strongly red-fluorescing (StrongRF) dentine, on which a composite cylinder was placed, using one of 4 adhesives. After 22 h in water, shear bond strength and fracture mode were analysed. StrongRF was removed; composite cylinders were placed on weakly red-fluorescing (WeakRF) dentine and tested as described above. Finally, red-fluorescing dentine was removed, and composite cylinders were placed on non-fluorescing (NonRF) dentine and tested. Composites were placed at 3 corresponding heights in controls. After 22 h in water, shear bond strength testing and fracture mode analysis were performed. Differences were tested using Mann-Whitney or Wilcoxon tests (p ≤0.05). Median (Q1, Q3) shear bond strength on StrongRF was SSE 14.4 (9.2, 18.2) MPa >CSE 10.2 (6.4, 17.3) MPa >STE 9.1 (6.9, 11.2) MPa >OTE 6.8 (4.0, 10.8) MPa. Shear bond strength increased statistically significantly for all adhesives on WeakRF: SSE 19.8 (13.6, 24.3) MPa >STE 19.5 (12.7, 23.1) MPa >CSE 17.5 (12.0, 22.5) MPa >OTE 15.8 (11.9, 20.9) MPa. Only STE 25.6 (22.4, 29.1) MPa and CSE 22.1 (17.6, 24.6) MPa were significantly different on NonRF compared to WeakRF. For controls tested at corresponding depths, superficial shear bond strength was OTE 18.7 (16.0, 22.1) MPa >STE 18.4 (12.0, 25.9) MPa >CSE 18.1 (12.7, 20.7) MPa >SSE 13.0 (9.6, 17.8) MPa. This was significantly higher compared to StrongRF except for SSE. Central shear bond strength was not significantly different to WeakRF, deep shear bond strength was significantly lower for SSE and CSE but higher for OTE compared to carious. Conclusion: StrongRF dentine should be removed for higher shear bond strength, but WeakRF dentine can often be preserved without compromising adhesive bond strength.

Efficacy of chlorhexidine, photosensitizers, green tea extract, and propolis on bond integrity and microleakage of caries-affected dentin: An in-vitro study

AimThe current study aimed to evaluate the efficacy of chlorhexidine (CHX), phycocyanin photosensitizer (PC), green tea extract (GTE), and propolis (PP) on the adhesive bond integrity and microleakage of caries-affected dentin (CAD) using etch and rinse adhesive system. Material and methodsA sum of 80 extracted human mandibular molars was collected and assessed using ICDAS criteria. Randomly CAD samples were treated with different disinfectants (n = 20) each CHX, PC, GTE, and PP. After ensuring disinfection, specimens were rehabilitated with bulk-fill composite resin employing etch and rinse adhesive system. SBS testing was performed by engaging (n=10) specimens in a universal testing machine. Microleakage analysis was performed by using the dye penetration technique.A stereomicroscope under 40× magnification was utilized for analyzing failure modes. Statistical analysis was accomplished by using the ANOVA and Tukey's post hoc tests (p<0.05). ResultsHighest bond strength was displayed by CAD disinfection with CHX and bonded to resin cement (15.33 ± 0.14 MPa). Whereas, the lowest SBS bond value was presented by Group 2 dentin surface disinfection with PC. CAD disinfected with GTE, PP and CHX demonstrated comparable SBS(p>0.05). The maximum microleakage score was exhibited when CAD bonded to resin cement disinfected with PP. While the minimum microleakage score was unveiled CAD bonded to resin cement sanitized with CHX ConclusionCaries-affected dentin bonded to resin cement, chlorhexidine exhibited the highest adhesive shear bond strength with a minimal microleakage score using etch and rinse adhesive system.

The effectiveness of the use of fifth-generation adhesive systems if changing the protocol before and after thermal cycling

Fifth-generation adhesives are very popular in daily clinical practice. They have reduced number of components by combining a primer and an adhesive in a «single bottle». These adhesives have become more popular due to the reduction of application stages, but their adhesion strength to dentin turned out to be worse than that of the fourth-generation adhesives. The main mechanisms of adhesion of any dental material: moistening of the surface, micromechanical adhesion, chemical adhesion.Aim. To evaluate the bond strength of tooth tissues with the filling material using different fifth-generation adhesive protocols.Materials and methods. We used the 40 exctracted teeth due to orthodontic indications (molars and premolars). In preparation for the experiment the teeth were randomly divided into 2 equal groups according to the number of adhesive protocols used: control and main. The teeth surfaces (n=20) of the control group were treated according to the instructions, the surface treatment with a moistening agent was added to the protocol of teeth surfaces (n=20) in the main group before applying the adhesive. After curing of the adhesive a 3×3 steel detachable cylindrical mold was installed on the surface of the samples (n=40) of both groups filled with a composite paste. The prepared samples of the control (n=10) and main (n=10) groups of 2 subgroups were subjected to thousands (1000s) thermocycles with a temperature of (5±2) °C and (60±2) °C. Tests of the adhesive shear bond strength of the prepared (n=40) samples of the control (n=20) and main (n=20) groups before and after thermocycling were carried out on a universal testing machine SYNTHEZ 5.Conclusion: Thermocycling provides the reliable adhesion but reduces the adhesive strength of the filling material with hard tissues of the tooth. Adding of moisturizing agent into the protocol leads to a decrease in the adhesion strength up to 15% compared to 7% in protocol without it.

Evaluation of bond strength of molar orthodontic tubes subjected to reinforcement with flowable and bonding resins

The goal was to evaluate the adhesive shear bond strength (SBS) of orthodontic tubes bonded to molar teeth and reinforced with Transbond XT (3M Science, St. Paul, MN, USA) and flowable resin. In all, 120molar teeth, previously extracted from patients with amean age of30 were included. Orthodontic molar tubes were bonded on the vestibular surface of these teeth with one of two types of adhesive (Transbond XT [3M Science, St. Paul, MN, USA] or Orthobond [Morelli, Sorocaba, Brazil]). Each of these groups was subsequently divided into four further groups: control and those subjected to the use of resin reinforcement on the occlusal surface of the bonded tubes with one of three materials (Transbond XT, Tetric N Flow [Ivoclar Vivadent, Ellwangen, Germany], Z350 Flow [3M Science, St. Paul, MN, USA]). SBS and adhesive remnant index tests were performed to evaluate bond strength and type of fracture of the tubes bonded with the different methods. The use of resin reinforcement with Transbond XT significantly increased the SBS of tubes bonded with both materials. Flowable composites did not increase the SBS when used as areinforcement. Less than 50% of the adhesive remained on the vestibular surface after the SBS test in most samples of all groups. Transbond XT orthodontic adhesive and Orthobond adhesive had appropriate bonding strengths for clinical use. Furthermore, the use of aresinous reinforcement with Transbond XT significantly increased the SBS of tubes bonded. However this technique with flowable adhesives (Tetric N Flow and Z350 Flow) did not significantly increase SBS when orthodontic tubes were bonded with Transbond XT or Orthobond.

In Vitro Study Compared The Shear Bond Strength of HEMA-free and HEMA-containing Bonding Agents To Different Dentin Surface Treatments

This research was designed to investigate the effect of two dentin surface treatments on the shear bond strength of HEMA-free and HEMA containing bonding agent. A total of 90 freshly extracted, sound human molars, free from caries, extracted for pathological reasons was used in this study. The molars were randomly divided into two main equal groups (45 teeth each) according to the type of adhesive system; Group (A1) used HEMA-free adhesive (G-bond). Group (A2) used HEMA containing adhesive (One-up Bond F Plus). Each group was further subdivided into 3 equal subgroups(15teeth each) according to the type of dentin surface treatments applied as follows: Subgroup (I) used the bonding agent only without surface treatment as a control [AB], Subgroup (II) used 10% Sodium hypochlorite followed by the bonding agent [AB1], Subgroup (III) used 10% Sodium hypochlorite then 10% Sodium ascorbate followed by the bonding agent [AB2]. Each subgroup was further divided into three groups of (5 teeth each) according to the storage times; 24 hours, three months, and six months. A Flat dentin surface was prepared, different surface treatments and adhesive systems were applied then Composite was bonded to the treated surfaces according to the manufacturer’s instructions and the shear bond strength testing was done using universal testing machine. The recorded values were tabulated and statistically analysed. The result of this study revealed that; the highest mean shear bond strength (18.39 +/- 2 MPa) wasrecorded for those dentin specimens bonded to composite resin with HEMA-containing adhesive (One-up Bond F Plus) without surface treatment after 1 day storage time. While the lowest mean shear bond strength (10.7 +/- 1.6 MPa) was recorded for those dentin specimens bonded to composite resin with HEMA-free adhesive (G-bond) with sodium hypochlorite only after 6 months storage time. The results of this study revealed that 1- Sodium hypochlorite only has a significant adverse effect on the shear bond strength of both adhesives. 2- sodium hypochlorite followed by sodium ascorbate can render the adverse effect of sodium hypochlorite only on the shear bond strength of both adhesives.3- HEMA-containing adhesive (One-up Bond F Plus) without surface treatment showed better shear bond strength than HEMA-free adhesive (G-bond). 4-Storage in water for long periods has a highly significant adverse effect on the bondstrength especially of HEMA-containing adhesive.

Casein phosphopeptide-amorphous calcium phosphate and shear bond strength of adhesives to primary teeth enamel.

Background:CPP-ACP (Phosphopeptide-Amorphous Calcium Phosphate) has an important role in caries prevention in pediatric patients. This study was done, because of the great use of CPP-ACP and the need for restoration for teeth treated with CPP-ACP as well as the importance of shear bond strength of adhesives in the success of restorations.Objectives:This study aimed to evaluate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on shear bond strength of dental adhesives to enamel of primary teeth molars.Materials and Methods:This in vitro study was conducted on 180 extracted primary molars. They were randomly divided into 6 groups and each group was divided into 2 subgroups (treated with CPP-ACP and untreated). In subgroups with CPP-ACP, enamel was treated with CPP-ACP paste 1 h/d for 5 days. Types of adhesives that were evaluated in this study were Tetric N-Bond, AdheSE, AdheSE One F, single Bond 2, SE Bond, and Adper Prompt L-Pop. Shear bond strength was tested with a universal testing machine and mode of failure was evaluated under stereomicroscope. Data were analyzed by T test, 2-way analysis of variance (ANOVA), Tukey and Fisher exact test using SPSS18. P < 0.05 was considered as significance level.Results:Shear bond strengths of different adhesive systems to enamel of primary teeth treated and untreated with CPP-ACP showed no significant difference (P > 0.05). Mode of failure in all groups regardless of CPP-ACP administration was mainly adhesive type. Our results indicated that CPP-ACP did not affect shear bond strength of studied adhesives to primary teeth enamel.Conclusions:To have a successful and durable composite restoration, having a high strength bonding is essential. Considering the wide use of CPP-ACP in preventing tooth decay and the role of adhesive shear bond strength (SBS) in success of composite restoration, we conducted the present study to evaluate the effect of CPP-ACP on the SBS of adhesives to primary teeth enamel.

Influence of saliva contamination on the shear bond strength of adhesives on enamel

OBJECTIVE: To evaluate shear bond strength of 3 adhesive systems (Single Bond, TransbondTM MIP and TransbondTM XT) applied on bovine enamel under saliva contamination condition. METHOD: One hundred and twenty enamel surfaces of bovine incisors were divided into 6 groups (n = 20) according to the adhesive system used (TransbondTM XT, TransbondTM MIP and Single Bond) with or without saliva contamination. For each adhesive system, there were two groups defined as no contamination group (NC): 37% H3PO4 conditioning for 30 seconds and two layers of adhesive systems; saliva contamination group (SC): After the first adhesive layer application, the examined areas were contaminated with saliva. Samples were mounted appropriately for testing and stored in deionized water at 37 oC for 7 days. Samples were then submitted to shear bond strength trials at a speed of 0.5 mm/min. The Adhesive Remnant Index (ARI) was evaluated under stereomicroscopy. Two-way analysis of variance and the Tukey test were used to compare mean values (α = 0.05). RESULTS: Groups XT (NC) = 26.29 ± 7.23; MIP (NC) = 24.47 ± 7.52 and SB (NC) = 32.36 ± 4.14 XT (SC) = 19.59 ± 6.76; MIP (SC) = 18.08 ± 6.39 and SB (SC) = 18.18 ± 7.03 MPa. ARI 0 and 1 were the most prevalent scores in all study groups examined. CONCLUSION: Saliva contamination significantly decreased bond strength of the three adhesive systems examined (p <0.05). However, the comparison of groups with and without saliva contamination did not reveal any significant differences, and, therefore, the three systems may be considered equivalent.

Bonding of adhesives to Er:YAG laser-treated dentin

The shear bond strength of adhesives applied to dentin was investigated after irradiation with an erbium-doped yttrium aluminum garnet (Er:YAG) laser. Superficial and deep dentin specimens from human molars were treated either with carbide bur or an Er:YAG laser. Two etch and rinse adhesives (Single Bond and XP Bond) and two self-etch adhesives (Prompt L-Pop and Xeno III) were employed to bond the composite. Shear bond strength (SBS) was determined after storage in water for 24 h using a universal testing machine with a crosshead speed of 0.5 mm/min. Failure patterns and modes were analyzed and evaluated using a stereomicroscope. In addition, samples were processed for Scanning Electron Microscopy SEM evaluation. A linear mixed model was used, and pairwise comparisons were made using the Bonferroni test. Results showed significant differences between the levels of dentin treatment (p=.01) in carbide bur-cut dentin and lased dentin, as well as significant interaction effects due to the depth of dentin and the bonding system used. The etch and rinse adhesives bonded less effectively with lased dentin than with carbide bur-cut dentin, while self-etch adhesives bonded equally well with lased and bur-cut superficial dentin but much less effectively with lased deep dentin than with bur-cut deep dentin. SEM revealed a predominantly adhesive failure mode in laser-ablated fractured specimens, while a mixed failure mode was apparent in the bur-cut fractured specimens. Cavities prepared by laser seem less receptive to adhesive procedures than conventional bur-cut cavities.

Pre- and co-curing effect of adhesives on shear bond strengths of composite resins to primary enamel and dentine: An in vitro study

To evaluate and compare shear bond strengths of composite resins to primary enamel and dentine when the adhesives are pre-cured (light cured before the application of the resin) or co-cured (adhesive and the resin light cured together). Buccal surfaces of 80 caries-free primary molars were wet ground to create bonding surfaces on enamel and dentine and specimens mounted on acrylic blocks. Two bonding agents (Prime and Bond NT® and Xeno III®) were applied to either enamel or dentine as per manufacturer's instructions. In 40 specimens, the bonding agent was light cured immediately after the application (pre-cured). The other 40 specimens were not light cured until the composite resin application (co-cured). Resin composite cylinders were made incrementally using acrylic moulds over the adhesives and light cured. Specimens were stored in deionised water for 24 hours at room temperature. Shear bond strength was measured using an Instron universal testing machine (in MPa) and was analysed with Student's unpaired t test. Light curing the adhesive separately produced significantly higher bond strengths to primary dentine than co-curing (p<0.001). At the same time light curing the adhesive separately did not produce significantly different bond strengths to primary enamel (p>0.05). Curing sequence had no significant effect on shear bond strength of adhesives on the primary enamel. Pre-curing adhesives before curing composite resins produced greater shear bond strength to primary dentine.

Effect of glutaraldehyde and ferric sulfate on shear bond strength of adhesives to primary dentin

Effect of glutaraldehyde and ferric sulfate on shear bond strength of adhesives to primary dentin

Shear bond strength of orthodontic adhesives on different tooth types : an in vitro study

Introduction: Owing to the variety of materials and methods employed, comparison of the results and findings from bonding studies is difficult. Until recently, several types of teeth have been used in published research papers as a substrate in orthodontic bonding research including bovine incisors, fresh and rebonded human premolars. Objectives: The purpose of this study was to compare the shear bond strength of an adhesive bonded to different tooth surfaces (human premolar, bovine incisor and rebonded human premolar). Methods: Two groups of thirty premolar teeth and one group of bovine incisors had brackets attached in a standardized manner using Transbond XT (3M Unitek). The adhesive was cured using conventional halogen light and a specially designed tool to standardize the distance between the light curing tip and the adhesive. The debonding force was measured using Instron universal testing machine. ANOVA and Post Hoc Dunnett C test were performed to determine any significant difference among groups (p<0.05). Results: The results of Post Hoc Dunnett C test indicated no statistical differences between the human premolar group and rebonded group. However, the differences existed in bond strength between bovine group versus human premolar group and bovine group versus human rebonded premolar group. Bovine group had the highest bond strength with mean values of 8.5 (S.D ? 4.2) MPa. Human premolar and rebonded groups had mean bond strengths of 6.1(S.D ? 4.5) and 4.9 (S.D ? 2.7) MPa, respectively. Conclusions: This study revealed that bovine teeth produced higher bond strength compared to both fresh and rebonded human premolar. Therefore, findings in any bond strength studies using bovine teeth should be interpreted with caution.

Effect of a self-etching primer on shear bond strength of adhesive precoated brackets in vivo.

The aim of this study was to evaluate the influence of a self-etching primer (SEP) (Transbond Plus SEP, 3M Unitek, Monrovia, Calif) on shear bond strength of adhesive uncoated and precoated Victory brackets (3M Unitek). The sample group consisted of 23 patients, with four premolars each, equally divided in four different groups. Brackets were bonded in vivo by the same operator using a split-mouth random technique: group 1, 37% phosphoric acid + primer + composite + conventional Victory bracket; group 2, 37% phosphoric acid + primer + precoated Victory bracket; group 3, SEP + composite + conventional bracket; group 4, SEP + precoated bracket. After 30 days, premolars were extracted for orthodontic reasons and a Universal Instron Machine was used to apply an occlusal shear force directly to the enamel-bracket interface at a speed of 0.5 mm/min. The groups were compared using two-way analysis of variance. Mean results and standard deviation for the groups were: group 1 = 11.60 +/- 2.65 Mpa, group 2 = 9.79 +/- 2.71 Mpa, group 3 = 10.75 +/- 2.67 Mpa, and group 4 = 10.31+/- 2.70 Mpa. No difference was observed between the conventional etching and primer or SEP (P = .948). However, significant differences in bond strength were present between the uncoated and precoated brackets (P = .032). Considering the values required to withstand normal orthodontic forces (8-9 Mpa), it could be concluded that the SEP combined with adhesive precoated brackets showed adequate shear bond strength and may be suitable for clinical use.

The effect of grafted caged silica (polyhedral oligomeric silesquioxanes) on the properties of dental composites and adhesives

With the emergence of commercial grafted caged silica (Polyhedral Oligomeric Silesquioxanes, POSS) having a three-dimensional (3D) morphology with peripheral functionality, new opportunities have been created for formulating dental adhesives and composites with enhanced mechanical and physical properties. The objective of the present study was to investigate the properties obtained by incorporating grafted caged silica into acrylate based dental composite and adhesive systems. Two commercial POSS materials (methacrylated and octaphenyl grafted) were added to dental restorative-glass-filled pre-polymers, based on BisGMA (bis-phenol A-glycidyldimethacrylate), HEMA (2-hydroxyethylmethacrylate) and TEGDMA (tetraethylglycidylmethacrylate). The nanostructured organic/inorganic hybrid compounds exhibited enhanced mechanical and thermal properties in cases where the POSS added was in concentrations up to 2 wt%. Beyond this threshold concentration, properties decreased due to agglomeration. In the case of the acrylated POSS, the T g increased by 5°C, the composite compressive strength by 7%, and the bond shear strength by 36% and the shrinkage was reduced by 28% compared with neat dental composites and adhesives. Furthermore, in the case of octaphenyl grafted POSS, the compressive strength was reduced by 20%, the adhesive shear bond strength decreased by 49% and the shrinkage was reduced by 67%. It was concluded that the type of the grafted functional group of the caged silica was the dominant factor in nano-tailoring of improved dental composites and adhesives.

In vitro dentin pretreatment: surface roughness and adhesive shear bond strength.

The aim was to define the morphology and roughness of dentin from different tooth areas after various pretreatments to identify the effect of hybrid layer, resin tags, and mineralised dentin surface on shear bond strength. Thirty-eight extracted molars were used, each providing two sections of cervical (c) and lateral (l) dentin. Five pretreatments were performed: A) 0.2% EDTA; B) abrasion with Al2O3 particles, 0.2% EDTA; C) 10% H3PO4; D) 10% H3PO4 and immersion in a collagenase solution; E) control: no treatment. Z100 composite resin cylinders were bonded to the specimens with All Bond 2 bonding resin and tested for shear bond strength. Twelve other specimens from each group were analysed with an optical profilometer and an atomic force microscope, and four were further examined by scanning electron microscopy (SEM). Mean shear strength values in MPa were: Ac: 8.36 +/- 4.23; Al: 8.77 +/- 3.68; Bc: 6.05 +/- 3.62; Bl: 8.39 +/- 4.60; Cc: 6.87 +/- 3.45; Cl: 9.00 +/- 5.62; Dc: 13.30 +/- 5.45; Dl: 8.44 +/- 4.47; Ec: 4.10 +/- 1.54; El: 6.09 +/- 4.34. No statistically significant difference for cervical versus lateral dentin was found within treatments except for group D. Treatments performed on lateral dentin did not differ significantly. In cervical dentin, A differed from E; C from E; and D from A, B, C and E. An increased surface roughness was found in group D. Shear bond strength to dentin did not seem to depend on a hybrid layer formation, but on the direct contact of the adhesive with the mineralised dentinal surface and partly on the orientation of the dentinal tubules.

The effect of tray material and surface condition on the shear bond strength of impression materials

This study compared the adhesive shear bond strength of three selected impression materials with that of thermoplastic and acrylic resin tray materials as a function of surface preparation. Polyether (Impregum), polyvinylsiloxane (Reprosil), and polysulfide (Permlastic) impression materials were evaluated on smooth, rough, and contaminated tray surfaces. Smooth surface samples were formed against glass and served as the control groups. Experimental groups consisted of samples contaminated with artificial saliva and rough surface samples that were abraded with 110 microns of Al203. A total of 126 samples were subdivided into 18 groups of seven specimens each. Each sample consisted of a 1 inch square, 3 mm thick mass of an impression material sandwiched between the prepared surfaces of a pair of resin plates. Each specimen was tested in a universal testing machine for adhesive shear bond strength. Data were analyzed with three-way analysis of variance and Scheffe's test. The results indicated that the thermoplastic resin material had better adhesive properties than the acrylic resin. For both tray materials mean adhesive shear bond strengths for Impregum and Reprosil were significantly greater than those of Permlastic. Tray surface contaminated with saliva decreased the adhesive shear strength at the tray adhesive impression interface.