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PubMed2001

Six-month clinical evaluation of two dentin adhesives applied on dry vs moist dentin.

PURPOSE: Acid-etched dentin has been described to easily collapse when it is dried with air after being rinsed with water under laboratorial "ideal" conditions. Manufacturers of modern dentin adhesives recommend leaving dentin moist, regardless of the solvent used in their proprietary dentin adhesives. Nevertheless, many clinicians still dry the cavity preparation after rinsing off the etching gel to check for the enamel frosted aspect. The null hypothesis to be tested in this clinical study was that drying dentin with air upon rinsing off the acid would not result in lower short-term retention rates than when the cavity was left visibly moist. MATERIALS AND METHODS: Upon Internal Review Board approval, thirty-five patients were enrolled in this study. A total of 128 restorations divided into four groups were inserted and evaluated at baseline: (A) Prime & Bond NT, an acetone-based adhesive, applied on moist dentin; (B) Prime & Bond NT applied on dentin dried with air for 3 to 4 s; (C) Single Bond, an ethanol- and water-based adhesive, applied on moist dentin; (D) Single Bond applied on dentin dried with air for 3 to 4 s. A microfilled composite resin was used for all restorations. RESULTS: At 6 months after initial placement, 119 restorations (a 93% recall rate) were re-evaluated. Retention rates at 6 months were 97% (one failure) for Single Bond/moist dentin and 100% for the remaining three groups; however, they were not significantly different (retention rate vs dentin adhesive; retention rate vs moisture). CONCLUSION: Dentin substrate in noncarious lesions may be less sensitive to variations in dentin moisture than the "ideal" dentin substrate used under laboratory conditions.

Acetone↗
PubMed2002

Morphological characterization of single bottle adhesives and vital dentin interface.

PURPOSE: To evaluate the in vivo interfacial relationship between four one-bottle adhesives and dentin. MATERIAL AND METHODS: Four one-bottle adhesives (Scotchbond 1, Syntac SC, One-Step and Prime & Bond 2.1) were applied on flat dentin surfaces on human anterior teeth scheduled for extraction for dentures. A three-step adhesive system (Scotchbond Multi-Purpose) was used as a control. After adhesive application, a thin layer of composite was applied and light cured. The teeth were extracted immediately after resin curing. All samples were split fractured along their long axis. Half of the samples were deproteinized and decalcified at the interface in order to visualize the hybrid layer. The other halves were completely dissolved to observe the morphology of the resin tags. RESULTS: All the one-bottle adhesives produced hybrid layers and resin tags at the dentin-resin interface. The three-step adhesive showed the same interfacial image but with a thicker hybrid layer and longer resin tags.

Acetone↗
PubMed2002

Influence of smear layer pretreatments on bond strength to dentin.

PURPOSE: To evaluate the tensile bond strength of two self-etching adhesive systems and one one-bottle system applied on dentin surfaces after different smear layer treatments. MATERIALS AND METHODS: The crowns of 36 extracted third molars were transversally sectioned with a diamond saw to expose dentin. Flat dentin surfaces were abraded wet with 600-grit SiC paper and randomly assigned to 12 groups, according to three adhesive systems--Prime & Bond NT (PB), Clearfil Mega Bond (CMB) and Etch & Prime 3.0 (EP)--and four dentin surface treatments: direct application over smear layer (no treatment), sandblasting with 50 microm Al2O3 for 10 s, etching with 36% phosphoric acid for 15 s, or conditioning with 0.5 M EDTA for 2 min. Composite "crowns" (6.0 mm high) were incrementally built on the bonded surfaces and teeth were stored in distilled water at 37 degrees C. Teeth were vertically, serially sectioned in both x and y directions to obtain bonded specimens of approximately 0.8 mm2 cross-sectional area. Each specimen was tested in tension in a universal testing machine at 0.5 mm/min. RESULTS: Overall microtensile bond strength (MPa) was 40.43 +/- 7.63 for PB, 27.03 +/- 8.40 for CMB, and 14.73 +/- 3.91 for EP. Mean bond strength for PB was significantly higher than self-etching systems. No significant differences were observed among smear layer treatments within the same dentin adhesive. CONCLUSION: Bond strength values were significantly different according to the adhesive system used. Different smear layer treatments prior to bonding did not affect tensile bond strength within the same bonding agent.

Acid Etching, Dental↗
PubMed2002

Marginal adaptation of self-etching adhesives in Class II cavities.

PURPOSE: An in vitro dye-penetration study was performed on 2 different self-etching adhesives (Prompt L-Pop II, 3M-Espe; NRC, Prime&Bond NT Quix, Dentsply/DeTrey) in comparison to conventional conditioning of the cavity with phosphoric acid (Conditioner 36, P&B NT Quix, Dentsply/DeTrey). MATERIALS AND METHODS: Standardized mod cavities (one cervical margin in cementum, one in enamel) were prepared in 80 extracted human teeth (n = 20/group). Prompt L-Pop II was employed in two different sequences: A: placing the matrix band first, then applying the adhesive, B: first applying the adhesive, then placing the matrix band. The adhesive was cured in both cases. Conditioning and application of P&B NT Quix was carried out after placement of the matrix band in both procedures. The compomer Dyract AP was used as a restorative material in all cavities. After thermocycling, the median percentages of dye-penetrated (2% methylene blue) margins were determined separately for the cementum and enamel margins of the approximal boxes and for the lateral enamel margins of the boxes. RESULTS: The results showed that when using Prompt L-Pop II in Class II cavities, the adhesive should be applied before placing the matrix band (p < 0.0001). When the matrix band was placed first, P&B NT Quix showed superior results at a statistically significant level (p < 0.0001) in comparison to Prompt L-Pop II. There was no significant difference in the use of P&B NT Quix in combination with NRC or phosphoric acid in these Class II cavities. CONCLUSION: It is strongly recommended that Prompt L-Pop be applied prior to placement of the matrix band. Prime & Bond NT Quix seems to provide clinically relevant marginal seal in Class II cavities, regardless of whether NRC or phosphoric acid is used for conditioning.

Acid Etching, Dental↗
PubMed2003

Cytotoxicity of dentin conditioners and primers on human periodontal ligament cells in vitro.

PURPOSE: To examine the cytotoxicity of dentin conditioners and primers on human periodontal ligament (PDL) cells in vitro. MATERIALS AND METHODS: Primary PDL cells were plated in 96 well culture plates and exposed to 100 microL of test solutions. Undiluted Cavity Conditioner (CC), Vitremer Primer (VP), Uni-Etch (UE), All-Bond 2 (AB), Gluma conditioner (GC), and Gluma primer (GP) were examined at full strength and at 1/100 and 1/1000 dilutions in culture medium. Cytotoxicity of the undiluted material was determined immediately following exposure of the cells to the test substance. Cytotoxicity of the diluted materials was determined immediately following a 300-second exposure of the cells to the test solution, as well as 24 hours after removal of the test solution. Cytotoxicity was expressed as lactate dehydrogenase activity retained within the cells following exposure divided by the activity in unexposed control cells. RESULTS: Exposure to each undiluted test substance resulted in severe damage to the cells (78.2-100%). At 1/100 dilution, only exposure to UE resulted in significant cytotoxicity (72.9%) immediately following removal of the solution. But significant cytotoxicity (21-100%) was evident in cells 24 hours after removal of each of the materials. At 1/1000 dilution, exposure to UE (14.8%) and GP (27.2%) resulted in mild cytotoxicity. Twenty-four hours after removal of the solutions, there was a mild but significant cytotoxic effect of each of the test substances (18.5-49.4%).

Acid Etching, Dental↗
PubMedDate not supplied

Bond strengths of Dyract AP compomer material to dentin of permanent and primary molars: phosphoric acid versus non-rinse conditioner.

PURPOSE: The purpose of this in vitro study was to determine the shear bond strengths (SBS) of Non-Rinse Conditioner (NRC, Dentsply) combined with Prime & Bond NT (PBNT, Dentsply), a 1-bottle adhesive. The null hypothesis tested was that the use of NRC with PBNT would not result in SBS different from those obtained with conventional phosphoric acid (PA) etching and bonding application to permanent and primary dentin. METHODS: Extracted human third molars and primary molars were mounted length-wise in acrylic resin. The occlusal surfaces were ground to expose a flat dentin surface, and then polished to 600 grit silicon carbide paper to create smear layers similar to those created with high-speed burs. The teeth were randomly assigned to 4 groups (N = 10) according to the etchant/conditioner (PA vs NRC) and dentin (permanent vs primary) used: (Group I: permanent dentin, PA, PBNT; Group II: primary dentin, PA, PBNT; Group III: permanent dentin, NRC, PBNT; Group IV: primary dentin, NRC, PBNT). Specimens were then secured in a split mold, having a 5 mm diameter opening and a polyacid-modified resin composite (Dyract AP, Dentsply) were inserted and light cured incrementally onto the treated dentin surfaces. All specimens were stored in water for 24 hours prior to shear strength testing using a Franell testing machine at a crosshead speed of 0.8 mm/minute. RESULTS: The mean dentin SBS values (MPa) for the groups were: Group I (13.32 +/- 6.6); Group II (15.21 +/- 5.25); Group III (8.87 +/- 3.12); and Group IV (7.42 +/- 2.98). Analysis of variance and Duncan's multiple range tests indicated significant differences among groups at P < 0.05. CONCLUSIONS: In general, the SBS were remarkably greater in the 2 groups etched with PA in comparison with the 2 groups conditioned with NRC. However, the type of dentin tissue did not influence SBS.

Acid Etching, Dental↗
PubMed2003

Microleakage of a single-bottle adhesive system with 3 restorative materials: in vitro study and clinical considerations.

The purpose of this study is to evaluate whether differences in material composition between 3 restoratives (compomer, packable composite, and amalgam) affect microleakage in class II preparations. Class II cavity preparations were made in the mesial and distal surfaces of a noncarious human premolar with the gingival margins in dentin. Preparations were etched and rinsed, and a single-bottle adhesive agent (Prime & Bond NT) was applied. Preparations were restored with the following materials (n = 8 per group): Dyract AP, SureFil, and Dispersalloy. For Dyract AP total-bond restorations, a new nonrinse conditioner (NRC) was tested against a total-etch with 36% phosphoric acid. Specimens were coated with nail varnish, immersed in toluidine blue for 24 hours, and evaluated for dye penetration, after removal of the restorative material, using a 0-to-4 scale. Statistical analysis using analysis of variance revealed significantly higher leakage scores (P < .05) for the NRC-Dyract AP group when compared with all other groups. Dispersalloy had significantly lower scores compared with Dyract AP and SureFil, all with the total-etch bonding technique. No statistically significant difference was observed between the latter 2 groups. The inability of all 3 materials to create a perfect seal in vitro raises concerns about the ability of the adhesive system to provide completely sealed restorations in vivo. However, bonded amalgam restorations are more effective in reducing marginal microleakage, particularly at the dentinal margin.

Acid Etching, Dental↗
PubMed2003

Influence of enamel surface preparation on composite bond strength.

PURPOSE: To evaluate the influence of air-particle abrasion and treatments on in vitro tensile bond strength of resin composite bonded to human enamel was evaluated using a single-bottle adhesive. METHODS: Human teeth were divided into 12 groups of three treatments (none, 27-microm Al2O3 air-particle abrasion, 50-microm Al2O3 air-particle abrasion) and four conditioners [none, phosphoric acid (PA), NRC (no-rinse conditioner), and PA/NRC]. Bonding agent (Prime & Bond NT) and a resin composite (TPH Spectrum) were applied as inverted cones. Specimens were stored for 24 hours at 37 degrees C and debonded in tension using a testing machine at 0.5 mm/minute. RESULTS: Phosphoric acid treatment used with Prime & Bond NT produced the best bond strengths (24 MPa) to enamel for surfaces treated with 27-microm air-particle abrasion and for surfaces not treated with air-particle abrasion (control). With one exception, air-particle abraded surfaces resulted in bond strengths between 9 to 16 MPa. NRC with or without the use of phosphoric acid in general did not improve tensile bond strength to enamel when compared to surfaces not treated with NRC.

Acid Etching, Dental↗
PubMed2003

Ultra-morphology of self-etching adhesives on ground enamel: a high resolution SEM study.

PURPOSE: To evaluate the effect of different commercial self-etching agents on enamel morphology using high-resolution in-lens scanning electron microscopy (FEISEM). METHODS: The bonding systems selected for the study were: Prime & Bond NT (no-etch technique), Prime & Bond 2.1 (no-etch technique), NRC/Prime and Bond NT, Syntac Single Component, Prompt L-Pop, F2000, and Clearfil SE Bond. The positive control group was prepared with Single Bond upon etching enamel with the proprietary 35% phosphoric acid gel. 24 extracted human molars were equally and randomly assigned to the experimental and control groups. All bonding materials were applied on enamel following the manufacturers' instructions. A thin layer of composite was applied on the polymerized adhesive agent, after which the enamel was dissolved to obtain replicas that were observed under a FEISEM. RESULTS: Observations revealed different morphological features brought about by the adhesive systems. A relationship between the morphological appearance and the pH of the adhesive solutions was found. Three different groups of self etching were identified: Group 1 showed no or little evidence of modifications on the enamel surface (Prime & Bond NT and Prime & Bond 2.1, no-etch technique), Group 2 revealed major aggressive properties that were able to disclose the prism morphology (Syntac Single Component, F2000, Clearfil SE Bond), and Group 3 (NRC/Prime & Bond NT and Prompt L-Pop) revealed morphological features similar to those obtained with Single Bond after etching with phosphoric acid (control group).

Acetone↗
PubMed2004

Bonding to enamel and dentin using self-etching adhesive systems.

OBJECTIVES: This study investigated the effectiveness of three different dentin adhesive systems on the adhesion of resin composite to both dentin and enamel. METHOD AND MATERIALS: The flat dentin and enamel surfaces of 60 extracted human molar teeth were exposed by wet grinding with 600-grit silicon carbide paper. One total-etch self-priming adhesive system (Prime & Bond NT), one two-step self-etching primer adhesive system (Clearfil SE Bond), and one "all-in-one" self-etching adhesive system (Prompt L-Pop) were evaluated. Each bonding system was applied according to the manufacturer's instructions and followed by composite (TPH Spectrum) application. Twenty-four hours after bonding, the teeth were subjected to shear testing. There were 10 replicates for each group. RESULTS: Prompt L-Pop exhibited significantly higher bond strength values to enamel (27 +/- 4.2 MPa) than all other groups. There were no statistically significant differences for shear bond strength to dentin among adhesives. Prompt L-Pop showed the statistically significantly higher bond strength to enamel than dentin. There were no statistically significant differences between the enamel and dentin bond strengths of Clearfil SE Bond and Prime & Bond NT. CONCLUSIONS: The self-etching adhesive systems produced high bond strengths to human coronal dentin and ground enamel surfaces. These materials seem to be very promising for further clinical applications, and the results are very encouraging for the clinical success of these simplified adhesive systems. The self-etching adhesive systems produced even better bond strengths to both enamel and dentin than conventional total-etch systems, especially the "all-in-one" system, which produced the highest bond strength to enamel.

Acid Etching, Dental↗
PubMedDate not supplied

Evaluation of the bonding mechanism of an adhesive material to primary teeth.

PURPOSE: The aim of this study was to evaluate with scanning electron microscopy (SEM) the bonding mechanism of the one-bottle adhesive Prime&Bond NT (Dentsply, PBNT) to enamel and dentin of deciduous teeth, following different methods of substrate treatment. METHODS: Eighteen extracted posterior deciduous teeth were randomly divided into 6 groups (N=3). The experimental groups differed for substrate and method of substrate conditioning prior to bonding with PBNT. Group 1: 36% phosphoric acid (PA)/PBNT on dentin; group 2: PA/PBNT on enamel; group 3: non-rinsing conditioner (NRC) (Dentsply)/PBNT on dentin; group 4: NRC/PBNT on enamel; group 5: PBNT on dentin without any previous conditioning; group 6: PBNT on enamel without any previous conditioning. On all the specimens, following the application of the adhesive solution, Dyract AP was layered on top and light-cured. The bonded specimens were processed for SEM observations. RESULTS: When used in combination with 36% phosphoric acid, PBNT was able to form a hybrid layer with resin tags on both enamel and dentin. Following conditioning with NRC, a thinner hybrid layer with shorter resin tags was developed on dentin; on enamel an etching pattern was still detectable. When only PBNT was applied without any previous conditioning, on dentin neither hybrid layer nor resin tags were visible; no sign of micromechanical bonding could be seen on the untreated enamel. CONCLUSIONS: The bonding mechanism of the one-bottle adhesive Prime&Bond NT on enamel and dentin of deciduous teeth is effective only following substrate conditioning with 36% phosphoric acid or NRC.

Acid Etching, Dental↗
PubMed2004

Identification of collagen encapsulation at the dentin/adhesive interface.

PURPOSE: The purpose of this study was to investigate the dentin/adhesive interfacial characteristics of three current commercial adhesives with different relative hydrophilic/hydrophobic composition, using a nondestructive staining technique. MATERIALS AND METHODS: Dentin surfaces of 18 unerupted human third molars were randomly selected for treatment with one of three commercial dentin bonding agents according to manufacturers' instructions for the "wet" bonding technique. The adhesives were ranked based on hydrophilic/hydrophobic component ratios (ie, ability to dissolve in water), highest to lowest, as follows: Uno (Pulpdent) > Prime&Bond NT (PBNT, Dentsply Caulk) > Single Bond (SB, 3M ESPE). Dentin/adhesive (d/a) interface sections were stained with Goldner's trichrome, a classical bone stain, and examined using light microscopy. RESULTS: The extent and degree to which the adhesive encapsulates the demineralized dentin matrix is reflected in the color differences in the stained sections. The depth of demineralization appeared comparable among these bonding systems, but adhesive infiltration varied from highest to lowest as follows: Uno > PBNT > SB. CONCLUSIONS: The differential staining technique provided a clear representation of the depth of dentin demineralization and extent/degree of adhesive encapsulation of the exposed collagen at the d/a interface. This technique provides a mechanism for readily identifying vulnerable sites at the d/a interface. The composition of the one-bottle adhesive systems has a substantial effect on the interfacial structure of the d/a bond.

Acid Etching, Dental↗
PubMed2004

The effect of sodium hypochlorite on microleakage of composite resin restorations using three adhesive systems.

PURPOSE: The aim of this study was to evaluate the effect of three different adhesive systems on microleakage of Class V restorations after the use of sodium hypochlorite. MATERIALS AND METHODS: One-hundred eighty bovine incisors were selected and randomly divided into 9 groups (n = 20): G1: Single Bond (SB); G2: 10% NaOCl solution (NS) + SB; G3: 10% NaOCl gel (NG) + SB; G4: Prime & Bond NT (PB); G5: NS + PB; G6: NG + PB; G7: Gluma One Bond (GOB); G8: NS + GOB; G9: NG + GOB. Standardized Class V cavities were prepared. All teeth were etched with 37% phosphoric acid for 15 s. In groups 2, 5, and 8, a 10% NaOCl solution was applied for 60 s to the dentin, and in groups 3, 6, and 9, a 10% NaOCl gel was applied to dentin for 60 s. All cavities were restored with composite resin Definite. The specimens were thermocycled for 1000 cycles (5 degrees C to 55 degrees C) and then immersed in 2% buffered solution of methylene blue for 4 h. The specimens were sectioned and analyzed according to a ranking score (0 to 4). Kruskal-Wallis and Mann-Whitney non-parametric tests (p < or = 0.05) were used for statistical analysis. RESULTS: The NaOCl treatment significantly increased microleakage at the dentin margin (p = 0.0129) as shown by the following sums of ranks: G1 = 1008.0a; G4 = 1301.5ab; G3 = 1687.0ab; G7 = 1744.0bc; G2 = 1802.0c; G9 = 1880.0c; G5 = 1889.0c; G8 = 1950.0c; G6 = 1963.0c (different superscripts indicate significant differences). For enamel, there were no statistically significant differences among the groups (p > 0.05). CONCLUSION: Depending on the adhesive system used, the application of NaOCl increased microleakage along dentin margins.

Acid Etching, Dental↗
PubMedDate not supplied

Clinical evaluation of a polyacid-modified resin composite under different conditioning methods in primary teeth.

This study evaluated the clinical performance of a polyacid-modified resin composite, Dyract AP (De Trey/Dentsply), under different conditioning methods in primary teeth. Eighty-one box-shaped cavity preparations (three restorations per patient) on the mesial or distal surfaces of primary first or second molars were prepared in 27 patients. The cavity preparations were either non pre-treated or pre-treated with 36% phosphoric acid or NRC (De Trey/Dentsply). The teeth were restored with Prime & Bond NT (De Trey/Dentsply) and Dyract AP. The restorations were evaluated at baseline and 6, 12 and 18-month recalls according to the modified Ryge criteria by two calibrated operators. The data obtained from the clinical assessment of all restorations were subjected to statistical analysis by chi-square-tests at a 0.05 level of significance. The ratings of each criteria were compared among each evaluation period between treatment groups. Statistical analysis revealed no significant difference among each evaluation period between groups in regard to color match, marginal discoloration, marginal adaptation, secondary caries, surface texture, anatomic form and retention.

Acid Etching, Dental↗
PubMedDate not supplied

The effect of adhesive and flowable composite on postoperative sensitivity: 2-week results.

OBJECTIVE: To measure 2-week postoperative sensitivity in Class II composite restorations placed with a self-etching adhesive (Clearfil SE Bond) or a total-etch adhesive (Prime&Bond NT) with or without a flowable composite as cervical increment. METHOD AND MATERIALS: Upon approval by the University of Guarulhos Committee on Human Subjects, 100 restorations were inserted in 46 patients who required Class II restorations in their molars and premolars. Enamel and dentin walls were conditioned with a self-etching primer (for Clearfil SE Bond) or etched with 34% phosphoric acid (for Prime&Bond NT). A 1- to 2-mm-thick increment of a flowable composite (Filtek Flow) was used in the proximal box in 50% of the restorations of each adhesive. Preparations were restored with a packable composite (Surefil). The restorations were evaluated preoperatively and 2 weeks postoperatively for sensitivity to cold, air, and masticatory forces using a visual analog scale. Marginal integrity of the accessible margins was also evaluated. Statistical analysis used a mixed linear model with subject as a random effect. RESULTS: Ninety-eight teeth from 44 subjects were observed at 2 weeks. The type of adhesive and use of flowable composite had no significant effects or interaction for any of the four outcomes of interest, ie, change from baseline to 2 weeks in sensitivity and response time for the cold or air stimulus. For the air stimulus, the overall average change from baseline was not significant for either sensitivity or response time. For the cold stimulus, the overall average change from baseline was significant for both sensitivity and response time. No case of sensitivity to masticatory forces was observed. CONCLUSION: No differences in postoperative sensitivity were observed between a self-etch adhesive and a total-etch adhesive at 2 weeks. The use of flowable composite did not decrease postoperative sensitivity.

Acid Etching, Dental↗
PubMed2004

Resin-infiltrated-dentine--a FE-ESEM microscopy investigation.

The formation of a hybrid layer is essential for bonding of dental composites to dentine. The objective of this study was to examine the effects of various etchants/conditioners and dentine bonding systems on dentine surfaces utilising a Field Emission Environmental SEM (FE-ESEM). Twenty one, freshly extracted human molar teeth were utilised. Dentine without resin application was initially observed both wet and dried in the following conditions: (1) fractured surface, (2) smear layer, and (3) smear layer removed with 37% phosphoric acid. Resin infiltration into dentine was then studied after applying Scotchbond 1, Optibond Solo, Prime & Bond NT, or Prompt L-Pop systems. Scotchbond 1, Optibond Solo, and Prime & Bond NT resins penetrated the dentine tubules and created hybrid layers; although, in some cases Prime & Bond NT only created a partially filled hybrid layer. No polymerised resin or hybrid layer was observed for Prompt L-Pop. The FE-ESEM permitted observation of specimens at near in-vivo wet conditions.

Acid Etching, Dental↗
PubMed2004

Shear bond strength of four core materials to dentin bonded with light-cured or dual-cured adhesive.

PURPOSE: To measure and compare the shear bond strength of four core materials to dentin bonded with one adhesive (Prime and Bond NT) that was either light-cured or dual-cured. METHODS: The dentin of 80 freshly extracted molars was exposed using a series of abrasive disks. The teeth were divided into eight equal groups, etched with phosphoric acid for 15 seconds and rinsed. Dentin was dried to a moist surface. On 40 teeth, Prime and Bond NT was applied and light-cured for 30 seconds. On 40 teeth, Prime and Bond NT was mixed with the self-cure additive, which was applied to the dentin, and light-cured for 20 seconds. The core materials were then placed following manufacturers' directions onto the cured adhesive. The core material was light-cured, when it was necessary, for 60 seconds and stored for 24 hours in water at room temperature. The specimens were loaded in shear in the Instron until failure at a 5 mm/minute crosshead speed. Data were compared using two factor ANOVA and Tukey's HSD test (P = .05). RESULTS: Both curing mode and core material showed a significant difference. A significant difference between mean shear bond strength for dual and light cured was observed only in CompCore (P = 0.0002). There was no statistical difference when Prime and Bond NT dual-cured was used with chemical- or dual-cured materials.

Acid Etching, Dental↗
PubMedDate not supplied

A confocal microscopic evaluation of resin-dentin interface using adhesive systems with three different solvents bonded to dry and moist dentinan in vitro study.

OBJECTIVE: Total dehydration of acid-etched dentin is known to cause the collapse of collagen fiber, which leads to poor hybridization. Dentin-bonding systems with water as a solvent are found to rehydrate the collapsed collagen. Acetone-based adhesives are found to compete with moisture, and the acetone carries the resin deep into the dentin. The question arises whether to dry the dentin and use a water-based adhesive, or to keep the dentin moist and use an acetone- or alcohol-based adhesive. The aim of this study was to compare different bonding systems and techniques to assess which is most successful. A confocal microscope was used to evaluate the amount of hybrid layer formation and the depth of resin tag formation. METHOD AND MATERIALS: Superficial occlusal dentin specimens from 120 noncarious, freshly extracted human premolars were used for the study. The dentin was etched using 36% phosphoric acid for 15 seconds and then rinsed. The specimens were then randomly divided into 4 groups for different drying procedures: group I: air-dried for 30 seconds; group II: air-dried for 3 seconds; group Ill: blotted dry; group IV: overwet. The specimens were further subdivided into 3 groups to be tested with different bonding systems: subgroup A: acetone-based adhesive (Prime & Bond NT); subgroup B: water-based adhesive (Syntac Single Component); subgroup C: water- and ethanol-based adhesive (Single Bond). The resulting resin-dentin interfaces were then examined and categorized via confocal microscopy, and relative values were assigned to each specimen. RESULTS: Group IV (overwet) showed the lowest values, and the highest values were obtained in group III. The highest values were seen in group III, subgroup A (blotted dry, acetone-based bonding agent, Prime & Bond NT). CONCLUSION: Under these conditions, using these three bonding systems, maximum hybridization and resin tag formation was achieved using acetone-based adhesive on etched dentin kept moist by blot drying.

Acetone↗