Artificial intelligence in the detection and classification of dental caries.

STATEMENT OF PROBLEM: Automated detection of dental caries could enhance early detection, save clinician time, and enrich treatment decisions. However, a reliable system is lacking. PURPOSE: The purpose of this study was to train a deep learning model and to assess its ability to detect and classify dental caries. MATERIAL AND METHODS: Bitewings radiographs with a 1876×1402-pixel resolution were collected, segmented, and anonymized with a radiographic image analysis software program and were identified and classified according to the modified King Abdulaziz University (KAU) classification for dental caries. The method was based on supervised learning algorithms trained on semantic segmentation tasks. RESULTS: The mean score for the intersection-over-union of the model was 0.55 for proximal carious lesions on a 5-category segmentation assignment and a mean F1 score of 0.535 using 554 training samples. CONCLUSIONS: The study validated the high potential for developing an accurate caries detection model that will expedite caries identification, assess clinician decision-making, and improve the quality of patient care.

Dimensional Changes of Yttria-stabilized Zirconia under Different Preparation Designs and Sintering Protocols.

PURPOSE: To evaluate the linear and volumetric dimensional changes that occur throughout the fabrication process of monolithic 4.5-6% yttria-stabilized zirconia copings under the influence of different preparation designs and two sintering protocols. MATERIALS AND METHODS: A titanium master die was fabricated using Atlantis core file implant-abutment. Six copings were designed virtually according to different finish line offsets and coping thicknesses, with four equidistant occlusal posts for linear measurements. Zirconia copings were milled using IPS e.max ZirCAD LT zirconia blanks. The experimental groups according to the coping designs were the following: G1: 0.5 mm finish line offset, 0.5 mm thickness; G2: 0.5 mm finish line offset, 1.0 mm thickness; G3: 0.5 mm finish line offset, 1.5 mm thickness; G4: 1.2 mm finish line offset, 0.5 mm thickness; G5: 1.2 mm finish line offset, 1.0 mm thickness; G6: 1.2 mm finish line offset, 1.5 mm thickness. Six samples per group were sintered by standard sintering (SS) and the other six by fast sintering (FS). Linear and volumetric measurements were taken at the three fabrication stages (virtual design, milling stage, and sintering) by using an intraoral scanner and imported as the .stl file to Meshmixer software for analysis. Statistical analysis was performed by a linear mixed effect model via statistical software R (R Core team, 2018). RESULTS: There was a significant interaction between the coping design group, stage of fabrication and sintering protocol on the linear (F = 4.451, p < 0.001) and volumetric (F = 2.716; p < 0.001) dimensional changes. Standard sintering G1 showed the smallest linear and dimensional changes among the groups compared to the reference design. Sintered copings had shrunk on average 1.32% within SS and 1.54% within FS linearly and 3.82% within SS and 3.90% within FS volumetrically compared to the initial design parameters. CONCLUSION: The linear and volumetric dimensional changes did not differ significantly between standard and fast sintering protocols, and the preparation designs had more influence on the dimensional changes compared to sintering protocols.

Variable Smear Layer and Adhesive Application: The Pursuit of Clinical Relevance in Bond Strength Testing.

The removal or modification of smear layers that cover the dentin is critical to allow the penetration of adhesive molecules and to ensure a strong bond between resin and dentin. Aiming to establish a model for clinically-relevant dentin-bond testing, we evaluated the effects of smear layers created by abrasives having similar coarseness (180-grit SiC paper; fine-grit diamond bur) and application modes (single application; double application) on the microtensile bond strengths (µTBS) of two currently available universal adhesives (G-Premio Bond; Scotchbond Universal Adhesive) and a two-step self-etch adhesive (Clearfil Megabond 2). Sixty extracted human third molars were used for the µTBS test. Data were analyzed by three-way ANOVA and Tukey's test (α = 0.05). Fracture modes were determined using stereomicroscopy. An additional 24 third molars were prepared for observation of the resin-dentin interface by TEM and adhesive-smear layer interaction by SEM. µTBS was significantly affected by the adhesives and their application modes (p < 0.001), implying that the double application of universal adhesives should be recommended to improve their performance. The effect of smear layers was not significant (p > 0.05), indicating that 180-grit SiC papers could be used to prepare dentin as a substitute for fine-grit diamond burs for dentin-bond testing in laboratory settings.

Effect of the flavonoid epigallocatechin-3-gallate on resin-dentin bond strength.

PURPOSE: To evaluate the effect of dentin pretreatment with epigallocatechin-3-gallate solution on the preservation of the resin/dentin interface with etch-and-rinse adhesives. MATERIALS AND METHODS: Thirty extracted human molars were prepared to expose the dentin surface and divided into 5 groups according to the pretreatment solution. Dentin surfaces were etched (35% phosphoric acid for 15 s), rinsed, and air dried. Dentin was rewetted either with distilled water, 3 different epigallocatechin-3-gallate solutions (EGCG; 0.02%, 0.1%, or 0.5% w/v), or 2% chlorhexidine digluconate solution for 60 s. Adper Single Bond 2 was applied and a subsequent 5-mm-thick resin crown was built up. Bonded teeth were longitudinally sectioned to obtain sticks with a cross-sectional area of 1.0 mm2. Half of the specimens were immediately tested, while the remaining specimens were tested after storage in 3 mMol/l sodium azide solution at 37°C for six months. The mode of fracture was examined. Bond strength values were analyzed with ANOVA and Student-Newman-Keuls tests. RESULTS: After 24 h of storage, mean bond strengths of 0.5% EGCG were significantly lower than those found for the other groups (p < 0.05), except for 0.02% EGCG (p > 0.05). Resin-dentin bond strengths after 6 months were not significantly different among the experimental groups (p > 0.05). Storage in water for 6 months resulted in a significant decrease in bond strength for the water control group only (p < 0.05). The bond strengths of the experimental groups remained stable after 6 months of water storage (p > 0.05). CONCLUSION: Pretreatment with EGCG preserved the bond of Adper Single Bond 2 to dentin after six months of storage equally well as pretreatment with chlorhexidine digluconate.

Microtensile bond strengths for six 2-step and two 1-step self-etch adhesive systems to enamel and dentin.

PURPOSE: To examine the microtensile bond strengths (microTBS) of six 1-step and one 2-step self-etch systems to dentin and ground enamel. METHODS: Resin composite buildups were bonded to buccal and lingual ground enamel surfaces, and to occlusal dentin of third molars using the following 1-step adhesives: Xeno IV (XE), GBond (GB), Clearfil S3 Bond (CS3); Adper Prompt L-Pop (AD); Go (GO) and All Bond SE (1-step; ABSE), in comparison to the 2-steps (All Bond SE; (2-step ABSE) and Clearfil SE Bond (CSE). After storage in water (24 hour/37 degrees C), the bonded specimens were sectioned into beams approximately 0.9 mm2. These beams were tested until failure at a crosshead speed of 0.5 mm/minute. Data were subjected to appropriate statistical analysis (alpha = 0.05). RESULTS: The total number of specimens/premature debonding specimens (PDS) for each adhesive were, respectively, in enamel: XE (59/36), GB (63/33), CS3 (62/29), AD (47/19), GO (53/14), 1-step ABSE (61/29), 2-step ABSE (57/14) and CSE (58/13); and in dentin: XE (51/24), GB (50/7), CS3 (53/13), ADP (51/1), GO (43/8), 1-step ABSE (59/2), 1-step ABSE (56/0) and CSE (47/0). The fracture pattern was predominantly adhesive/mixture for all adhesives in dentin (51.5 to 99%) and in enamel (34.8 to 75.4%), however XE (61.2) and GB (52.5) had more than 50% PDS. For ground enamel, no significant difference was detected among materials in the same subgroup (with or without PDS). However, there was a significant difference for all adhesives when subgroups (with and without PDS, respectively) were tested against each other: XE (7.9/10.5 double dagger 19.7/5.5), GB (8.6/10.5 double dagger 17.2/7.4), CS3 (8.8/10.3 double dagger 15.7/5.6), AD (13.0/12.0 = 20.3/8.9), Go (18.2/13.8 = 25.1/10.0), 1-step ABSE (15.9/11.4 = 16.2/5.4), 2-step ABSE (8.4/9.1 double dagger 25.3/7.9) and CSE (17.6/16.3 = 19.9/7.8). For dentin, no difference was found when subgroups for the same adhesive were tested against each other (with or without PDS). However, significantly higher resin-dentin bond strength was observed for adhesives in the following order: CSE (38.5/6.5 = 38.5/6.5) > or = 2-step ABSE (41.4/16.3 double dagger 42.4/19.3) = 1-step ABSE (43.9/17.7 = 44.2/17.1) = AD (34.4/14.2 = 35.2/13.3) < or = CS3 (31.9/19.4 = 40.1/13.4) double dagger GB (14.3/6.3 = 16.3/5.9) = Go (14.2/13.9 = 22.4/12.6) double dagger XE (7.1/5.4 = 9.5/5.1), respectively for with PDS and without PDS. All materials showed similar performance on ground enamel. The performance of one-step self-etch systems to dentin appears to be material-dependent. Adper Prompt L-Pop, Clearfil S3 Bond and the 1-step All Bond SE had microTBS similar to Clearfil SE Bond and the 2-step All Bond SE, while Xeno IV and GBond had significantly lower microTBS values. Go had an intermediate performance.

Influence of technique and manipulation on self-adhesive resin cements used to cement intraradicular posts.

STATEMENT OF PROBLEM: Resin cements are widely used to cement intraradicular posts, but bond strength is significantly influenced by the technique and material used for cementation. PURPOSE: The purpose of this study was to evaluate the bond strength of 3 self-adhesive cements used to cement intraradicular glass fiber posts. The cements all required different application and handling techniques. MATERIAL AND METHODS: Forty-five human maxillary canines were selected and randomly divided into 3 groups n= 15 by drawing lots: Group BIS - Biscem, Group BRE - Breeze, and Group MAX - Maxcem. Each group was divided into 3 subgroups according to application and handling techniques: Sub-group A - Automix/Point tip applicator, Sub-group L - Handmix/Lentulo, and Sub-group C - Handmix/Centrix. Cementation of the posts was performed according to the manufacturers' instructions. The push-out test was performed with a crosshead speed of 0.5 mm/min, and bond strength was expressed in megapascals. The results were evaluated by 2-way ANOVA and the all pairwise multiple comparison procedures (Tukey test) (α=.05). RESULTS: Breeze cement showed the highest average for the subgroups A, L, and C when compared to the Biscem cement and Maxcem Elite (P<.05). Statistically significant differences among the subgroups were only observed for Biscem. CONCLUSIONS: This study shows that application and handling techniques may influence the bond strength of different self-adhesive cements when used for intraradicular post cementation.

Methods used by dental practice-based research network dentists to diagnose dental caries.

OBJECTIVES: To (1) identify the methods that dentists in The Dental Practice-based Research Network (DPBRN) use to diagnose dental caries; (2) quantify their frequency of use, and (3) test the hypothesis that certain dentist and dental practice characteristics are significantly associated with their use. METHODS: A questionnaire about methods used for caries diagnosis was sent to DPBRN dentists who reported doing some restorative dentistry; 522 dentists participated. Questions included the use of dental radiographs, the dental explorer, laser fluorescence, air-drying and fiber-optic devices and magnification as used when diagnosing primary, secondary/recurrent or non-specific caries lesions. Variations on the frequency of their use were tested using multivariate analysis and Bonferroni tests. RESULTS: Overall, the dental explorer was the instrument most commonly used to detect primary occlusal caries and caries at the margins of existing restorations. In contrast, laser fluorescence was rarely used to help diagnose occlusal primary caries. For proximal caries, radiographs were used to help diagnose 75%-100% of lesions by 96% of the DPBRN dentists. Dentists who use radiographs most often to assess proximal surfaces of posterior teeth were significantly more likely to also report providing a higher percentage of patients with individualized caries prevention (p = .040) and seeing a higher percentage of pediatric patients (p = .001). CONCLUSION: The use of specific diagnostic methods varied substantially. The dental explorer and radiographs are still the most commonly used diagnostic methods.

Mechanical Properties of Three-Dimensional Printed Provisional Resin Materials for Crown and Fixed Dental Prosthesis: A Systematic Review.

The emergence of digital dentistry has led to the introduction of various three-dimensional (3D) printing materials in the market, specifically for provisional fixed restoration. This study aimed to undertake a systematic review of the published literature on the Mechanical Properties of 3D- Printed Provisional Resin Materials for crown and fixed dental prosthesis (FDP). The electronic database on PubMed/Medline was searched for relevant studies. The search retrieved articles that were published from January 2011 to March 2023. The established focus question was: "Do provisional 3D-printed materials have better mechanical properties than conventional or milled provisional materials?". The systematically extracted data included the researcher's name(s), publication year, evaluation method, number of samples, types of materials, and study outcome. A total of 19 studies were included in this systematic review. These studies examined different aspects of the mechanical properties of 3D-printed provisional materials. Flexural Strength and Microhardness were the frequently used mechanical testing. Furthermore, 3D-printed provisional restorations showed higher hardness, smoother surfaces, less wear volume loss, and higher wear resistance compared to either milled or conventional, or both. 3D-printed provisional resin materials appear to be a promising option for fabricating provisional crowns and FDPs.

Abutment design for implant-supported indirect composite molar crowns: reliability and fractography.

PURPOSE: To investigate the reliability of titanium abutments veneered with indirect composites for implant-supported crowns and the possibility to trace back the fracture origin by qualitative fractographic analysis. MATERIALS AND METHODS: Large base (LB) (6.4-mm diameter base, with a 4-mm high cone in the center for composite retention), small base (SB-4) (5.2-mm base, 4-mm high cone), and small base with cone shortened to 2 mm (SB-2) Ti abutments were used. Each abutment received incremental layers of indirect resin composite until completing the anatomy of a maxillary molar crown. Step-stress accelerated-life fatigue testing (n = 18 each) was performed in water. Weibull curves with use stress of 200 N for 50,000 and 100,000 cycles were calculated. Probability Weibull plots examined the differences between groups. Specimens were inspected in light-polarized and scanning electron microscopes for fractographic analysis. RESULTS: Use level probability Weibull plots showed Beta values of 0.27 for LB, 0.32 for SB-4, and 0.26 for SB-2, indicating that failures were not influenced by fatigue and damage accumulation. The data replotted as Weibull distribution showed no significant difference in the characteristic strengths between LB (794 N) and SB-4 abutments (836 N), which were both significantly higher than SB-2 (601 N). Failure mode was cohesive within the composite for all groups. Fractographic markings showed that failures initiated at the indentation area and propagated toward the margins of cohesively failed composite. CONCLUSIONS: Reliability was not influenced by abutment design. Qualitative fractographic analysis of the failed indirect composite was feasible.

Effects of prolonged use of over-the-counter bleaching agents on enamel: An in vitro study.

This study evaluated the effects of four over-the-counter (OTC) bleaching products on the properties of enamel. Extracted human molars were randomly assigned into four groups (n = 5): PD: Poladay (SDI), WG: White Teeth Global (White Teeth Global), CW: Crest3DWhite (Procter & Gamble), and HS: HiSmile (HiSmile). The hydrogen peroxide (H2 O2 ) content in each product was analyzed via titration. Twenty teeth were sectioned into quarters, embedded in epoxy resin, and polished. Each quarter-tooth surface was treated with one of the four beaching times: T0: control/no-bleaching, T14: 14 days, T28: 28 days, and T56: 56 days. Materials were applied to enamel surfaces as recommended. Enamel surfaces were examined for ultramicrohardness (UMH), elastic modulus (EM), superficial roughness (Sa), and scanning electron microscopy (SEM). Ten additional teeth were used to evaluate color and degree of demineralization (DD) (n = 5). Data were statistically tested by two-way ANOVA and Tukey's tests (α = 5%). Enamel surfaces treated with PD and WG presented UMH values significantly lower than the controls (p < .05). Elastic modulus (E) was significantly reduced at T14 and T28 for PD, and at T14 for HS (p < .05). A significant increase in Sa was observed for CW at T14 (p < .05). Color changes were observed in the PD and WG groups. Additionally, DD analysis showed significant demineralization at T56 for CW. Overall, more evident morphological alterations were observed for bleaching products with higher concentrations of H2 O2 (p < .05), PD, and WG. Over-the-counter bleaching products containing H2 O2 can significantly alter enamel properties, especially when application time is extended.

Cause-Effect Relationship of Varying Bonding Thicknesses in Dentin Adhesion of Universal Adhesives.

PURPOSE: To evaluate whether varying thicknesses of universal adhesives utilizing the additional coating strategy would affect their microtensile bond strength (µTBS) to dentin, hardness, and elastic modulus (mechanical properties). MATERIALS AND METHODS: Ninety-nine human maxillary premolars were cut to expose coronal dentin, ground with regular-grit diamond burs, and randomly distributed into 9 groups based on 1. adhesive: Scotchbond Universal Adhesive (SB; universal), G Premio Bond (GP; universal) and Clearfil Megabond 2 (MB; two-step self-etch; control); and 2. application strategy (one, two or three coats; each coat light cured). After adhesive application and resin composite buildup, the bonded teeth were stored in distilled water (37°C; 24 h). Resin-dentin sticks from eight premolars per group (each premolar yielded 3 sticks; n = 24 sticks altogether) were prepared for the µTBS test, followed by measurement of the adhesive thicknesses at their fractured ends using SEM. The mechanical properties of the adhesive layers produced by different coats were evaluated on separate resin-dentin slices (n = 3 teeth per group). RESULTS: Two coats significantly increased the µTBS (p < 0.001) of all the adhesives. The correlation between adhesive thickness and bond strength was positive for GP but negative for SB. MB did not show any correlation. Additional coating significantly increased the mechanical properties of GP (p < 0.05) but did not affect SB and MB (p < 0.05). CONCLUSION: An additional adhesive coating over the manufacturers' recommendations improved the bond strength of all the adhesives tested. However, the increased mechanical properties of the adhesives with additional curing was material dependent.

Calcium silicate-coated porous chitosan scaffold as a cell-free tissue engineering system for direct pulp capping.

OBJECTIVES: This study aimed to develop and characterize different formulations of porous chitosan scaffolds (SCH) associated with calcium silicate (CaSi) and evaluate their chemotactic and bioactive potential on human dental pulp cells (hDPCs). METHODS: Different concentrations of CaSi suspensions (0.5%, 1.0%, and 2.0%, w/v) were incorporated (1:5; v/v) /or not, into 2% chitosan solution, giving rise to the following groups: SCH (control); SCH+ 0.5CaSi; SCH+ 1.0CaSi; SCH+ 2.0 CaSi. The resulting solutions were submitted to thermally induced phase separation followed by freeze-drying procedures to obtain porous scaffolds. The topography, pH, and calcium release kinetics of the scaffolds were assessed. Next, the study evaluated the influence of these scaffolds on cell migration (MG), viability (VB), proliferation (PL), adhesion and spreading (A&S), and on total protein synthesis (TP), alkaline phosphatase (ALP) activity, mineralized matrix deposition (MMD), and gene expression (GE) of odontogenic differentiation markers (ALP, DSPP, and DMP-1). The data were analyzed with ANOVA complemented with the Tukey post-hoc test (α = 5%). RESULTS: Incorporation of the CaSi suspension into the chitosan scaffold formulation increased pore diameter when compared with control. Increased amounts of CaSi in the CH scaffold resulted in higher pH values and Ca release. In Groups SCH+ 1.0CaSi and SCH+ 2.0CaSi, increased VB, PF, A&S, GE of DSPP/DMP-1 and MMD values were shown. However, Group SCH+ 2.0CaSi was the only formulation capable of enhancing MG and showed the highest increase in TP, MMD, and GE of DMP-1 and DSPP values. SIGNIFICANCE: SCH+ 2.0CaSi formulation had the highest chemotactic and bioactive potential on hDPCs and may be considered a potential biomaterial for pulp-dentin complex regeneration.

Characterization of an Experimental Two-Step Self-Etch Adhesive's Bonding Performance and Resin-Dentin Interfacial Properties.

This study evaluated an experimental two-step self-etch adhesive (BZF-29, BZF) by comparing it with a reference two-step self-etch adhesive (Clearfil Megabond 2, MB) and a universal adhesive (G-Premio Bond, GP) for microtensile bond strength (µTBS) and resin-dentin interfacial characteristics. Twenty-four human third molars were used for the µTBS test. Bonded peripheral dentin slices were separated to observe the resin-dentin interface and measure the adhesive layer thickness with SEM. µTBS data of the central beams were obtained after 24 h and 6 months of water storage. Fracture modes were determined using a stereomicroscope and SEM. Nine additional third molars were used to determine the elastic modulus (E) employing an ultra microhardness tester. Water storage did not affect µTBS of the tested adhesives (p > 0.05). µTBS of BZF and MB were similar but significantly higher than GP (p < 0.05). BZF achieved the highest adhesive layer thickness, while GP the lowest. E of BZF and MB were comparable but significantly lower than GP (p < 0.05). Except for GP, the predominant fracture mode was nonadhesive. The superior bonding performance of BZF and MB could be attributed to their better mechanical property and increased adhesive thickness imparting better stress relief at the interface.

Application of a New Microtensile Bond Strength Testing Technique for the Evaluation of Enamel Bonding.

OBJECTIVE: To evaluate adhesives' enamel bonding performance utilising the traditional microtensile bond strength test (µTBST) and a new double-sided microtensile bond strength test (DµTBST) to assess the suitability of the latter. METHODS: A 'tug-of-war' direct encounter design was employed to compare the enamel bond strengths of two universal adhesives and their different application modes simultaneously under the same tensile load applied to double-sided bonded specimens. Clearfil Universal Bond (CU; Kuraray, Kurashiki, Japan) and Scotchbond Universal Adhesive (SB; 3M ESPE, St Paul, MN, USA) were applied in self-etch (S) and etch-and-rinse (E) mode on 110 human molar samples to perform two experiments. Experiment 1 compared the enamel bond strengths of the combinations of adhesive application modes utilising µTBST. The data were analysed using a Welch analysis of variance (ANOVA), followed by a Games-Howell test. Experiment 2 employed DµTBST to determine the suitability of the new double-sided bonded assembly and ascertain which of the adhesive application mode combinations was superior. The data were analysed using a Kaplan-Meier survival analysis, followed by pairwise comparisons with a Mantel-Cox log-rank test. The level of significance was set at P ˂ 0.05. RESULTS: The µTBST results did not show significant differences for CUE vs CUS, SBE vs SBS, CUS vs SBS and CUS vs SBE (P ˃ 0.05); however, from DµTBST, the survival distributions for the interventions were statistically significantly different (χ2(3) = 145.130, P ˂ 0.0005), indicating the superiority of universal adhesive CU over SB and application mode E over S with certainty. CONCLUSION: DµTBST was able to add more discerning outcomes to the µTBST results, indicating that the new technique could become a valuable adjunct to the conventional method.

Consensus on glass-ionomer cement thresholds for restorative indications.

OBJECTIVE: The aim of this paper is to present the results of a consensus meeting on the threshold property requirements for the clinical use of conventional glass-ionomer cements (GICs) for restorative indications. METHODS: Twenty-one experts on GICs evaluated the results of tests on mechanical and optical properties of 18 different brands of restorative GICs: Bioglass R [B], Chemfil Rock [CR], Equia Forte [EF], Gold Label 2 [GL2], Gold Label 9 [GL9], Glass Ionomer Cement II [GI], Ionglass [IG], Ion Z [IZ], Ionomaster [IM], Ionofil Plus [IP], Ionostar Plus [IS], Ketac Molar Easymix [KM], Magic Glass [MG], Maxxion R [MA], Riva Self Cure [R], Vidrion R [V], Vitro Fil [VF] and Vitro Molar [VM]. All experiments were carried out by a team of researchers from Brazil and England following strict protocols, under the same laboratory conditions throughout, and maintaining data integrity. RESULTS: There was consensus on: determining as primary properties of the material: compressive strength, microhardness, acid erosion and fluoride release, and as secondary properties: contrast ratio and translucency parameter, in order to rank the materials. Seven brands were below the thresholds for restorative indications: IZ, IM, IG, MA, VF, B and MG. CONCLUSIONS: Based on the primary properties adopted as being essential for restorative indications, the conventional restorative GICs that met the thresholds and could be considered suitable as long-term restorative materials were: EF, GI, GL9, KM, IP, GL2, IS, CR, V, VM and R. A decision-making process to select the best GIC must also include results from clinical trials. CLINICAL SIGNIFICANCE: This study provides a ranking of GICs that could be considered suitable as long-term restorative materials based on their main properties.

Effect of mode of application on the microtensile bond strength of a self-etch and etch-and-rinse adhesive system.

UNLABELLED: This study examined the 24-hour microtensile bond strength (microTBS) of a three-step etch-and-rinse (All Bond 3 [AB3]) and a two-step self-etch system (All Bond Self-Etch [ABSE]) to dentin and ground enamel, varying the application mode. METHODS: AB3 was applied according to the following procedures: A-phosphoric acid + adhesive application. The adhesive was then light-cured before resin buildup. B-similar to Procedure A, except that a thin layer of bonding resin was applied over the cured adhesive; C-similar to Procedure B, however, the adhesive was not light-cured before application of the bonding resin. ABSE was applied according to the following procedures: A--the acidic adhesive was applied and light-cured; B--after the acidic adhesive application and light-curing, a thin layer of ABSE Liner was applied and light cured; C--similar to B, however, the acidic adhesive was not light cured before application of the ABSE Liner. Resin composite buildups (Charisma) were bonded to teeth substrates after adhesive application. The bonded specimens were sectioned into beams 0.9 mm2 after storage in water (24 hours/37 degrees C) and subjected to microTBS with a crosshead speed of 0.5 mm/minute. The average values (MPa) obtained in each substrate were subjected to two-way repeated measures ANOVA and the Tukey's test (alpha=0.05). RESULTS: No significant difference was observed among the experimental groups either in ground enamel or dentin. CONCLUSIONS: The 24-hour microtensile bond strength of All Bond 3 and All Bond Self-Etch was similar, regardless the mode of application of the adhesive systems.

Effect of oxalate desensitizer on the durability of resin-bonded interfaces.

Potassium oxalate desensitizers were previously shown to effectively reduce the immediate permeability of resin-bonded dentin. The current study evaluated whether the effect of the combined application of oxalate with etch-and-rinse adhesives interferes with the durability of resin-dentin bonds when using etch-and-rinse adhesives. The bond strength of resin-bonded dentin specimens composed of two-step or three-step etch-and-rinse adhesives (Single Bond, One-Step and Scotchbond Multi-Purpose, respectively) was tested immediately (24 hours) and after 12 months of water storage. The adhesives were used either according to the manufacturers' instructions (control groups) or after treating acid-etched dentin with a potassium oxalate gel (BisBlock, BISCO, Inc). The treatment of dentin with potassium oxalate was shown to negatively affect the baseline bond strength of resin-bonded dentin specimens, regardless of the adhesive used (p < 0.05). After storage, the bond strength of the resin-bonded interfaces was significantly reduced for all the tested groups (p < 0.001). Nevertheless, the rate of decreasing bond strength was significantly lower for oxalate-treated specimens than for the controls (p < 0.05).

A randomized clinical evaluation of a one- and two-step self-etch adhesive over 24 months.

OBJECTIVE: To evaluate the performance of All Bond SE used in a one- or two-step protocol in a 24-month randomized clinical study. METHODS: Thirty-three patients with two similarly sized non-carious cervical lesions participated in this study. A total of 66 restorations were placed, half using the one-step All Bond SE protocol (SE-1) and the other half using the two-step All Bond SE protocol (SE-2). The restorations were evaluated at baseline and after 6, 12 and 24 months following the modified USPHS criteria and analyzed by the McNemar's test and Fisher's exact test (alpha = 0.05). RESULTS: After 24 months, six SE-1 and four SE-2 restorations were rated as Bravo in marginal discoloration The retention rates for SE-1 and SE-2 were 84.8% and 90.9%, respectively, after 24 months. Compared to baseline, the retention rate for SE-1 was statistically lower. CONCLUSIONS: All Bond SE used in the one- or two-step protocol resulted in high retention rates after 24 months.

A 24-month randomized clinical trial of a two- and three-step etch-and-rinse technique.

PURPOSE: This 24-month randomized paired tooth clinical study evaluated the performance of All Bond 3 used in the simplified (2-step) and full (3-step) versions. METHODS: 33 patients, with at least two similar sized non-carious cervical lesions participated in this study. A total of 66 restorations were placed, half using the 2-step All Bond 3 (AB3-2) and the other half using 3-step All Bond 3 (AB3-3). The restorations were placed incrementally using the composite resin Aelite. The restorations were evaluated at baseline and after 6, 12 and 24 months following the modified USPHS criteria. Statistical differences between the adhesive were tested using with McNemar's test and clinical performance over time for each material with the Fisher's exact test (alpha = 0.05). RESULTS: After 24 months, six AB3-2 and four AB3-3 were rated as bravo for marginal discoloration but did not differ from each other significantly (P > 0.05). The retention rates at 24 months of AB3-2 and AB3-3 were 90.9% and 97.0%, respectively (P > 0.05).

Direct resin composite restorations versus indirect composite inlays: one-year results.

AIM: The aim of this study was to evaluate the clinical performance of direct resin composite restorations (Tetric Ceram-TC) and indirect composite inlays (Targis-TG) after 12 months. METHODS AND MATERIALS: Seventy-six Class I and II restorations (44 direct and 32 indirect) were inserted in premolars and molars with carious lesions or deficient restorations in 30 healthy patients according to the manufacturer's instructions. Each restoration was evaluated at baseline and after 12 months according to the modified USPHS criteria for color match (CM), marginal discoloration (MD), secondary caries (SC), anatomic form (AF), surface texture (ST), marginal integrity (MI), and pulp sensitivity (PS). Data were analyzed by Fisher and McNemar Chi-square tests. RESULTS: No secondary caries and no pulpal sensitivity were observed after 12 months. However, significant changes in marginal discoloration (MD) criteria could be detected between baseline and one-year results for both materials (p<0.05). For marginal integrity (MI) criteria, the differences between baseline and one-year recall were statistically significant (p<0.05). For marginal integrity (MI) criteria, Tetric Ceram (TC) showed results statistically superior to Targis (TG) in both observation periods (p<0.05). No statistically significant changes in color match (CM), anatomic form (AF), or surface texture (ST) appeared during the observation periods (p>0.05). CONCLUSIONS: BDirect resin composite restorations performed better than indirect composite inlays for marginal integrity, but all restorations were judged to be clinically acceptable. CLINICAL SIGNIFICANCE: Tetric Ceram direct restorations and Targis indirect inlays in posterior teeth provide satisfactory clinical performance and the comparison between them showed little difference after one year.