Total-etch System Research Articles

Hemostatic gingival retraction agents and their impact on prosthodontic treatment steps: A narrative review

The purpose of this topic review is to give a general overview of gingival retraction agents used during prosthodontic treatment, and the possible difficulties connected to them that may be faced by the dentist. Hemostatic agents are important for successful gingival retraction and in achieving hemostasis. However, these agents may show numerous negative effects on the prosthodontic treatment and oral tissues of which the practicing dentist must be aware, and which will be elucidated in this review. PubMed and Google Scholar databases were searched for publications up to and including 2017. The following key words were used in different combinations: "hemostatic agent," "astringent," "astringency," "epinephrine," "ferric sulfate," "aluminum chloride," "hemorrhage control," "soft tissue," "hard dental tissue," "self-etch adhesive," "total-etch adhesive," "bond strength," "impression," "gypsum," "plaster cast," and "dental cast." In the last three decades the hemostatic agents used by practicing dentists have changed from epinephrine towards astringents, with AlCl3 and Fe2(SO4)3 now the most popular. All of the currently known hemostatic agents cause some local, temporary gingival tissue damage, but only epinephrine is known to elicit negative systemic effects. Studies concerning the influence of hemostatic agents on impression materials show highly contradictory results regarding the possible polymerization-inhibiting properties of hemostatic agents, probably due to the lack of standardization of methodology. Hemostatic agents seem to alter the dentinal surface properties making it more resistant to acid etching. Therefore the relatively low acidity of self-etch adhesives when compared to total-etch systems may not be strong enough to sufficiently etch a more resistant dentinal surface, and consequently may result in lower adhesive bond strengths.

Ultramorphology of pre-treated adhesive interfaces between self-adhesive resin cement and tooth structures

Abstract Introduction Convencional resin cements can be used in combination with a total-etch system in a conventional mode or as self-adhesive resin cements. The latter are less technique sensitive and able to bond to dental tissues without previous treatment or adhesive layer and requires only a single step to be applied to dental structures. Objective To compare qualitatively the adhesive interfaces of two self-adhesive resin cements and one conventional resin cement after different tooth surface treatments under scanning electron microscopy. Material and method 42 crowns of bovine incisors were sectioned and flattened exposing enamel (E) or dentine (D) substrate. Subgroups were defined according to conditioning type and time: E1—no treatment, E2—37% phosphoric acid for 15 seconds, E3—37% phosphoric acid for 30 seconds; D1—no treatment, D2—37% phosphoric acid for 5 seconds; D3—11.5% polyacrylic acid for 15 seconds. A resin block was bonded to each substrate using the self-adhesive resin cements RelyX U100 (3M ESPE) and RelyX U200 (3M ESPE). As a reference hybrid layer, six resin blocks were luted with RelyX ARC and Scotchbond Multi-Purpose adhesive system (3M ESPE) (enamel—EA; dentine—DA). After aging for 7 days in a moist environment at 37±1°C, samples were prepared for microscopy analysis. Result and Discussion In the ARC specimens, there was hybrid layer formation in both EA and DA. U100 E1 showed gaps at the adhesive interface, while E2 and E3 showed interaction for both self-adhesive cements. There was superficial interaction with bothU100 and U200 in D1, while in D2 and D3, resin tags were only observed in the case of U100. Conclusion It was concluded that substrate conditioning may enhance the interaction between self-adhesive resin cements and dental tissues, although this is not the case for RelyX U200 and dentine.

Adhesive capability of total-etch, self-etch, and self-adhesive systems for fiber post cementation

The aim of this study was to analyze whether self-etch and self-adhesive systems are comparable to the total-etch system for fiber post cementation. This experimental laboratory study, which was approved by an ethics committee, was performed using 27 mandibular premolar teeth randomly divided into three groups. Fiber post cementation was done using three different adhesive systems. Specimens were prepared with a thickness of 5 mm, which was measured from the cervical to medial areas of the root, and stored for 24 h in saline solution at room temperature. A push-out test was performed using a universal testing machine (Shimidzu AG-5000E) with a crosshead speed of 0.5 mm/min. The results of one way ANOVA bivariate testing showed that the total-etch and self-etch systems have comparable adhesion capability (p<0.05) and that the self-adhesive system has the lowest adhesion capability (p>0.05). With easier application, the self-etch system has a comparable adhesion capability to the total-etch system.

Does laser diode irradiation improve the degree of conversion of simplified dentin bonding systems?

Simplified dentin-bonding systems are clinically employed for most adhesive procedures, and they are prone to hydrolytic degradation. Objective This study aimed to investigate the effect of laser diode irradiation on the degree of conversion (DC), water sorption (WS), and water solubility (WSB) of these bonding systems in an attempt to improve their physico-mechanical resistance.Material and Methods Two bonding agents were tested: a two-step total-etch system [Adper™ Single Bond 2, 3M ESPE (SB)] and a universal system [Adper™ Single Bond Universal, 3M ESPE (SU)]. Square-shaped specimens were prepared and assigned into 4 groups (n=5): SB and SU (control groups – no laser irradiation) and SB-L and SU-L [SB and SU laser (L) – irradiated groups]. DC was assessed using Fourier transform infrared spectroscopy with attenuated total reflectance. Additional uncured resin samples (≈3.0 µL, n=5) of each adhesive were also scanned for final DC calculation. For WS/WSB tests, similar specimens (n=10) were prepared and measured by monitoring the mass changes after dehydration/water storage cycles. For both tests, adhesive fluids were dropped into standardized Teflon molds (6.0×6.0×1.0 mm), irradiated with a 970-nm laser diode, and then polymerized with an LED-curing unit (1 W/cm2).Results Laser irradiation immediately before photopolymerization increased the DC (%) of the tested adhesives: SB-L>SB>SU-L>SU. For WS/WSB (μg/mm3), only the dentin bonding system (DBS) was a significant factor (p<0.05): SB>SU.Conclusion Irradiation with a laser diode improved the degree of conversion of all tested simplified dentin bonding systems, with no impact on water sorption and solubility.

Antibacterial Activity of Commercial Dentine Bonding Systems against E. faecalis–Flow Cytometry Study

Literature presents inconsistent results on the antibacterial activity of dentine bonding systems (DBS). Antibacterial activity of adhesive systems depends on several factors, including composition and acidity. Flow cytometry is a novel detection method to measure multiple characteristics of a single cell: total cell number, structural (size, shape), and functional parameters (viability, cell cycle). The LIVE/DEAD® BacLight™ bacterial viability assay was used to evaluate an antibacterial activity of DBS by assessing physical membrane disruption of bacteria mediated by DBS. Ten commercial DBSs: four total-etching (TE), four self-etching (SE) and two selective enamel etching (SEE) were tested. Both total-etching DBS ExciTE F and OptiBond Solo Plus showed comparatively low antibacterial activity against E. faecalis. The lowest activity of all tested TE systems showed Te-Econom Bond. Among SE DBS, G-ænial Bond (92.24% dead cells) followed by Clearfil S3 Bond Plus (88.02%) and Panavia F 2.0 ED Primer II (86.67%) showed the highest antibacterial activity against E. faecalis, which was comparable to isopropranol (positive control). In the present study, self-etching DBS exhibited higher antimicrobial activity than tested total-etching adhesives against E. faecalis.

Evaluation of Microleakage with Total Etch, Self Etch and Universal Adhesive Systems in Class V Restorations: An In vitro Study.

Adhesive dentistry is overwhelmingly evolving with respect to the dental surgeon's and patient's perspective. Embracing the concept of minimally invasive dentistry which follows minimum intervention performed to produce good adhesion and tooth coloured restoration, in turn makes the newer generation bonding agents more acceptable and appropriate withstanding the demand for stable restoration. To study and compare the extent of microleakage between tooth and restoration interface in class V composite resin restorations applying one Total Etch (AdperTM single bond), two Self Etch (AdperTM SE Plus, AdperTM Easy One) and Universal bonding agents using dye penetration method. A total of 120 freshly orthodontically extracted human maxillary and mandibular premolars were included in the study. Class V cavities were prepared with a cylindrical diamond bur on the facial surface of each tooth, having approximate dimensions of 3 mm × 2.5 mm × 1.5 mm. Teeth were divided into four groups (30 in each group). Group A AdperTM single bond 2 (3M ESPE), Group B AdperTM SE Plus (3M ESPE), Group C AdperTM Easy One (3M ESPE), Group D AdperTM Single Bond Universal (3M ESPE) bonding agents were applied as per the manufacturer's instructions and the cavities were then restored with nanohybrid composite resin (Tetric N Ceram Ivoclar Vivadent). Teeth were then thermocycled for 200 cycles at 5°-55°C with 60 seconds of dwell time. Specimens were subjected to a dye leakage test. Microleakage was evaluated using a stereomicroscope. Data was analysed using Kruskal- Wallis, Dunn and Mann-Whitney test to assess the difference in microleakage among various adhesives. The present study revealed that the microleakage was more at the gingival margin when compared with occlusal and this was found to be statistically significant. At the occlusal margin statistical significant difference was found only between AdperTM Easy one and AdperTM SE Plus, on the other hand at gingival margin no statistical significant difference was found. One step self etch agents showed less microleakage than total etches and universal adhesive at occlusal margin. Higher degree of microleakage was observed at gingival margin compared to occlusal margin.

Microtensile Bond Strength and Failure Modes of Flowable Composites on Primary Dentin with Application of Different Adhesive Strategies.

Background:Resin composite is an option for the restoration of primary teeth, and new materials with simplified procedures are increasingly being suggested.Aims:This study aims to evaluate the microtensile bond strengths and fracture modes of flowable composites on primary dentin with application of different adhesive strategies.Materials and Methods:Sixty extracted noncaries primary molars were abraded from buccal surfaces to expose dentin surface. The teeth were randomly divided into three groups as follows: Group 1, Vertise™ Flow (Kerr) (self-adhering flowable composite); Group 2, G-aenial Universal Flo® (GC Europe) (used with one-step self-etch system); Group 3, Tetric® N-Flow (Ivoclar/Vivadent) (used with two-step total etch system). Then, the flowable composites were applied to buccal dentin surfaces with the help of guide mold. Samples were embedded in acrylic blocks and sectioned to form dentin-composite sticks with a surface area of approximately 1 mm2. Finally, a total of 180 sticks were obtained to give each group of 60 sticks. Microtensile bond strengths were measured using a universal testing machine (1 mm/min). Fracture modes were evaluated with scanning electron microscopy.Statistical Analysis:Microtensile bond strengths data were analyzed by Kruskal–Wallis nonparametric test.Results:The microtensile bond strengths of G-aenial (15.5 megapascals [Mpa]) and Tetric (13.0 MPa) were statistically significant higher than Vertise (2.3 MPa). It was recorded that most of fractures in G-aenial was 40% cohesive, Tetric was 53.3% mixed, and Vertise was 83.3% adhesive.Conclusions:The self-adhering flowable composite Vertise™ Flow had the lowest and G-aenial Universal Flo® had the highest microtensile bond values.

Shear bond strength and debonding characteristics of a new premixed self-etching with a reference total-etch adhesive.

BackgroundTo determine the shear bond strength and adhesive remnant index of a new premixed self-etching primer and adhesive (Tectosan, BonaDent, Germany) for orthodontic appliances in comparison to a reference total-etch system Transbond XT.MethodsBovine incisors were embedded in resin and randomly divided into two groups of 16 samples each. Brackets (Discovery, Dentaurum, Germany) were bonded in group 1 (total-etch-system, Transbond XT) and in group 2 (self-etch-system, Tectosan) with curing light for 40 s. Shear bonding strengths were measured after 24 h of storage in distilled water at 37 °C with a Zwicki 1120 testing machine (Zwick Roell, Germany). A force was applied on the bracket base at the wings in occluso-gingival direction. Then the adhesive remnant index (ARI) was determined.ResultsNo statistical differences on SBS were found for both bonding agents (p = 0.63). ARI scores however differed statistically significantly (p = 0.035): in the total-etch group more adhesive remained on the teeth, whereas in the self-etch group more adhesive remained on the brackets. There were no visible enamel damages in both groups.ConclusionsNo differences in the shear bond strength were found between both bonding agents. In our study the self-etch-system shifted the adhesive remnant index from more adhesive on the teeth to more adhesive on the bracket - as other already published self-etch systems did - with the new benefit of not increased enamel damages. Tectosan might therefore be a promising alternative to adhesive systems.

THE EFFECT OF TWO DIFFERENT ADHESIVE SYSTEMS ON MICROLEAKAGE OF CLASS V COMPOSITE RESTORATION IN PRIMARY TEETH

INTRODUCTION: polymerization shrinkage of composite resins causes stresses that may exceed the strength of the bond with the surrounding tooth structure, leading to interfacial failure. The use of an adhesive system is always required. OBJECTIVE: The purpose of this in vitro study was to compare the effect of total-etch adhesive system with self-etch adhesive system on microleakage of universal nano-hybrid composite resin when used to restore class V cavities in primary teeth. MATERIALS AND METHODS: The sample consisted of 50 freshly extracted sound primary teeth. Standardized class V cavity preparations on the buccal surfaces were prepared and the sample was randomly divided into 2 equal groups: Group I: 25 teeth received total etch adhesive system. Group II: 25 teeth received self-etch adhesive system. The cavities were restored with a universal nano-hybrid restorative material. All specimens were thermocycled and immersed in 0.5% basic fuchsine dye at 37C˚ for 24 hours. Basic fuchsine penetration was assessed on a 4 point grading scale (0 to 4) using a stereomicroscope to evaluate the microleakage of the restorations. RESULTS: Comparing the percentage of microleakage scores of group I and group II at occlusal margin it was found that, the group I was significantly lower than group II (p=0.041). As for percentage of microleakage scores for the gingival margin between groups I and II it was found that there was no significant difference (p=0.741). Comparing the percentage of microleakage scores at both the gingival and occlusal margis of group I and II, no significant difference was revealed (p=0.105) (p=0.278) respectively. The sum of occlusal and gingival percentage of microleakage scores of group I compared to group II revealed no significant difference (p=0.325).. CONCLUSION: There is no significant difference in microleakage sum scores between total etch and self-etch adhesive system groups. At the occlusal margin, total-etch adhesive system was significantly better than the self-etch adhesive systems. KEYWORDS: microleakage, total etch adhesive, self- etch adhesive, primary teeth.

The effect of different cementation strategies on the pull-out bond strength of fiber post: an ex-vivo study

Background: The purpose of this study was to evaluate the influence of dual cure resin with total etch and self-etch adhesive systems, conventional glass ionomer and zinc phosphate cementing media on the retention of fiber posts. Methods: 60 freshly extracted bovine mandibular incisors were biomechanically prepared. Post space was created. The specimens were divided into four groups of 15 teeth each according to the material used for luting of posts. Group Z had zinc phosphate cement as luting agent, group R had dual cure resin cement with total etch adhesive (Relyx ARC cement), group G had conventional glass ionomer cement (GC Fuji) and group P had dual cure resin cement with self-etch adhesive (Panavi F). The posts were luted. Prepared samples were tested on the Universal testing machine for pull out strength. Results: Among the various cemented media tested best pull out bond strength was obtained with Relyx ARC and Panavia F followed by conventional glass ionomer cement. The pull-out strength of glass ionomer cement was slightly higher than zinc phosphate cement but the difference was statistically insignificant. Conclusions: Based on the results of this study it can be concluded the dual cure resin cement showed the best retention of the fibre glass posts followed by conventional glass ionomer.

Shear Bond Strength of Three Orthodontic Bonding Systems on Enamel and Restorative Materials.

Objective. The aim of this in vitro study was to determine the shear bond strength (SBS) and adhesive remnant index (ARI) score of two self-etching no-mix adhesives (iBond™ and Scotchbond™) on different prosthetic surfaces and enamel, in comparison with the commonly used total etch system Transbond XT™. Materials and Methods. A total of 270 surfaces (1 enamel and 8 restorative surfaces, n = 30) were randomly divided into three adhesive groups. In group 1 (control) brackets were bonded with Transbond XT primer. In the experimental groups iBond adhesive (group 2) and Scotchbond Universal adhesive (group 3) were used. The SBS was measured using a Zwicki 1120™ testing machine. The ARI and SBS were compared statistically using the Kruskal–Wallis test (P ≤ 0.05). Results. Significant differences in SBS and ARI were found between the control group and experimental groups. Conclusions. Transbond XT showed the highest SBS on human enamel. Scotchbond Universal on average provides the best bonding on all other types of surface (metal, composite, and porcelain), with no need for additional primers. It might therefore be helpful for simplifying bonding in orthodontic procedures on restorative materials in patients. If metal brackets have to be bonded to a metal surface, the use of a dual-curing resin is recommended.

Does 2% chlorhexidine digluconate cavity disinfectant or sodium fluoride/hydroxyethyl methacrylate affect adhesion of universal adhesive to dentin?

The objectives of this study were to investigate the adhesion of a universal adhesive used either in total-etch (TE) or self-etch (SE) mode with and without 2% chlorhexidine digluconate cavity disinfectant (CHX) or sodium fluoride/hydroxyethyl methacrylate (NaF/HEMA) to dentin. Dentin surfaces of extracted human non-carious third molar teeth (N = 18) were exposed and randomly assigned to two groups. Half of the teeth were conditioned with TE and the others with SE adhesive mode. The teeth were then randomly divided into two groups where half were cleaned with 2% CHX (Cavity Cleanser, Bisco, CC) and the other half with NaF/HEMA (Aqua Prep F, Bisco, APF). Control groups in TE (C1) and SE (C2) adhesive system did not receive any cavity disinfectant. Dentin surfaces were conditioned with universal adhesive (Single Bond Universal, SBU) and resin composite blocks (3 M Z550) were bonded incrementally on the conditioned dentin using a mold. The teeth were stored in water for 48 h, and from each tooth, beam-shaped specimens (1 mm2) were prepared (n = 14, per group). Microtensile bond strength (MBS) was measured using a universal testing machine (1 mm/min). Data (MPa) were analyzed using one-way ANOVA and Tukey’s test (α = 0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m), and shape (0) values were calculated. Mean MTBS results (MPa) showed significant difference between the experimental groups (p = 0.001) and were in descending order as follows: C1-CC (32.8 ± 6.4)a < C1 (24.4 ± 5.2)b < C2 (21.1 ± 4.8)b < C1-APF (19.3 ± 4.4)b < C2-CC (14.1 ± 4.1)c < C2-APF (8.1 ± 2.1)d. C1 and C2 presented non-significant bond strength of the resin composite bonded with SBU (p > 0.05). CC application significantly increased the bond strength in TE mode, but significant reduction was observed when used in SE mode (p < 0.05). The use of APF did not significantly decrease the bond strength in TE mode, but significant reduction was observed when used in SE mode. Considering Weibull parameters, characteristics of adhesion seem to be less reliable for C2-CC (m = 3.86) and more reliable for C1-CC (m = 6.77). Failure types were predominantly adhesive between the dentin and the adhesive resin. Mixed failures were more common for both C1 and C2 and total etch-CC combination.

A Comparative Evaluation of the Efficacy of Etching by the Total Etch and Self-etch Dentin Bonding Systems in the Primary Teeth: An in vitro Study.

ABSTRACTObjective: Early childhood caries is now affecting the children in dangerous proportions. There is a wide spread loss of the tooth material irrespective of the type of the carious lesion. Restoration of such lesions with a strong permanent bond between the dental tissues and the restorative dental materials would be a highly desirable requisite. Ultramorphological characterizations show that the interfacial morphology and the chemical characterization of the bonding systems appear to be strongly associated with each other and, therefore, observing and understanding the interfacial phenomenon and its quality would be of great importance in the selection of a dental adhesive for its use in pediatric restorative dentistry.Study design: Human primary molars, which were indicated for extraction, for an array of reasons like caries, normal exfoliation, pathological root resorption, over-retained and serial extraction, were collected for the study purpose. Total number of teeth was then equally distributed into two subgroups, each namely A1 (Prime and Bond NT) and A2 (Xeno III).Results: The type of etching pattern that was observed in group A1 (Prime and Bond NT) of Silverstone’s type II compared to the Silverstone’s type III observed in group A2 (Xeno III).Conclusion: Results of this study indicate that the use of an etchant separately followed by the application of the bonding system–Prime and Bond NT–would provide a better quality of adhesion thus improving the quality and longevity of the restoration done within the limits of enamel in primary dentition.How to cite this article: Mithiborwala SH, Chaugule V, Katge F, Poojari M, Pujari P, Pammi T. A Comparative Evaluation of the Efficacy of Etching by the Total Etch and Self-etch Dentin Bonding Systems in the Primary Teeth: An in vitro Study. Int J Clin Pediatr Dent 2015;8(1):30-36.

Influence of the bulk fill restorative technique on microleakage and microtensile of class II restorations

Abstract Background & Aim The aim of this study is to evaluate microleakage and bond strength test of the bulk fill restorative technique. Materials and methods AELITE LS Posterior and SureFil SDR flow were used as composite restoration, and Clearfil S 3 (Self Etch system) Bond and Prime&Bond NT (Total Etch system) were used as bonding agents. Standardized Class II cavities were made on sixty extracted premolar teeth and they were randomly divided into four groups. Thermo-cycling and mechanical loading was applied to all samples. The samples were stored in the %2 basic fuchsine solutions and the microleakage was evaluated. Results When total etching system groups were evaluated, the cervical microleakage values were higher than occlusal microleakage values on both composites ( P P Conclusions The results support the conclusion that the SureFil SDR flow exhibited the best performance in occlusal margins of Prime&Bond NT-SureFil SDR groups.

Evaluation and Comparison of Shear Bond Strengths of Self Etching Primers To Dentin– an In-Vitro Study

AbstractAn in-vitro evaluation was done to compare shear bond strength of four self etching primer adhesives to dentin. 75 human extracted molar teeth were selected. The occlusal surface of these teeth was ground to remove coronal enamel and expose dentin. The dentinal surface of each tooth was then abraded using series of silicon carbide (320, 400, 600 grit) abrasive paper. Teeth were divided into 5 groups of 15 teeth each and composite post were then built on the bonded surfaces using Z-100 hybrid composite. The teeth were then fractured applying shearing load through universal testing machine. Shear strength values were in the range of 15.96 to 22.64 Mpa. Clearfil S3 gave highest mean shear bond strength whereasAdhe SE gave lowest value of shear strength. Based on this study it could be concluded that contemporary self etching primer adhesives bond successfully to dentin and also their bonding ability seems to be comparable to conventional total etch system.

Estimation and comparison of tensile bond strengths at resin-dentin interface of total-etch and self-etch bonding systems

Objective: To estimate and compare the Tensile Bond Strengths and to observe the resindentin interface of total-etch and self-etch bonding systems to dentin of primary and permanent molar teeth.&#x0D; Method: Thirty non-carious exfoliated primary human molars and thirty extracted permanent molars were randomly assigned to four groups according to adhesives used. The specimens were subjected to tensile bond strength (TBS) testing at a crosshead speed of 1 mm/min. Mean TBS was statistically analyzed with student ‘t’ test. Interfacial morphologies were analyzed by Scanning Electron Microscopy (SEM).&#x0D; Result: Etch-and-rinse adhesive Adper Single Bond 2 Total Etch® yielded high bond strength when applied to both primary and permanent dentine. For the one-step Adper Easy One® self-etching adhesive, the bond strength was relatively low regardless of the dentine type. SEM interfacial analysis revealed funnel shaped resin tags and a rough hybrid layer in specimens subjected to total etch system and cylindrical shaped and a smooth hybrid layer in specimens subjected to self etch system in both primary and permanent teeth. &#x0D; Conclusion: The total-etch systems provide better adhesion to primary and permanent tooth dentine. The self etch systems though convenient to use, do not match the bond strengths of conventional total etch systems. Also, it can be concluded that both adhesives show weaker bond strengths to primary tooth dentin.&#x0D;

Influence of the bleaching agent and adhesive system on the bond strength of the restorative material to intracoronary dentin

The bond strength of dentin bleached with high concentrated agents can be reestablished if the appropriate restorative material is selected. Objective: The aim of this study was to evaluate the influence of bleaching agents and adhesive system on bond strength of restorative material to intracoronary dentin. Material and methods: 60 fragments of intracoronary dentin (25 mm2) were embedded in acrylic resin and divided into 3 groups (n = 10): GI – not bleached (control), GII – 35% hydrogen peroxide (35HP), GIII – 38% hydrogen peroxide (38HP). The gel was applied for 10 min onto the dentin surface. This protocol was repeated three times at a single session. After 14 days, the groups were divided into subgroups according to the adhesive system used in the restoration: A – Self-etching (Clearfil SE Bond) and B – Total etching (Single Bond 2). The fragments were restored with Z100 Filtek resin using a bipartite matrix. After 24 h, the specimens were subjected to shear bond strength test. Data were analyzed by two-way ANOVA and Tukey test (p &lt; 0.05). Results: The group bleached with 38HP(6.02 ± 3.95) had the highest bond strength to dentin, followed by 35HP (5.36 ± 3.54), and control group (3.11 ± 2.71) (p &lt; 0.05), although without statistically significant differences. It was also verified a higher bond strength in the group restored with the self-etching adhesive system (6.60 ± 4.18) when compared to the total etching system (3.06 ± 1.57). Conclusion: When performing the restoration of teeth bleached with hydrogen peroxide at high concentrations (35% and 38%), self-etching adhesive system should be the first choice.

Effect of Nd:YAG Laser Bleaching and Antioxidizing Agents on the Shear Bond Strength of Brackets

The aims of this study were to evaluate the effect of hydrogen peroxide bleaching agents, both nonactivated and activated by a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, and of antioxidant treatment on the shear bond strength (SBS) of orthodontic brackets. Nd:YAG laser activation is expected to accelerate the bleaching therapy without decrease shear bond strength. Ninety extracted maxillary central incisors were divided into two experimental groups and a control group. Group I was the control group, Group II was bleached with 35% hydrogen peroxide and had no photoactivation, and Group III was bleached with 35% hydrogen peroxide with activation by a Nd:YAG laser (4.0 W, 60 Hz frequency, 1 mm distance, 20 sec). Each group was divided into two subgroups: Subgroup A was immersed in artificial saliva for 2 weeks, and then bonded using the total etch system, whereas subgroup B was treated with an antioxidant agent (10% sodium ascorbate) and then bonded using the same system. The samples were stored in water for 24 h at 37°C, and thermocycled. The SBS in megapascals (MPa) was determined by a shear test with 1 mm/min crosshead speed, and failure types were classified with modified adhesive remnant index scores. The data were analyzed with two way analyses of variance, Tukey, and χ(2) tests at the α = 0.05 level. In both Groups II and III, the SBSs of brackets bonded after bleaching (Group II 15.16, Group III 17.50 MPa) were significantly lower than those of brackets in the bonded unbleached group (Group I 22.13 MPa); however, sodium ascorbate treatment significantly increased the SBSs of brackets in the bleached groups (Group II 21.52, Group III 22.43 MPa), but had an insignificant effect on the SBS of the control group (Group I 23.66MPa). Hydrogen peroxide bleaching agents reduce the SBSs both with and without Nd:YAG laser activation; however, treatment of the bleached enamel surface with 10% sodium ascorbate prior to bonding negates the effect.

Histologic Evaluation of Human Pulp Response to Total Etch and Self Etch Adhesive Systems

BackgroundTo investigate pulp response to the application of two types adhesive systems (total-etch and self-etch) in human premolar teeth.Materials and MethodsCavities limited to enamel walls in all margins with 2.5 mm depth were prepared on buccal surfaces of thirty three human premolars. The cavities were treated with the following adhesive. Single Bond (SB) and Prompt L-Pop (PLP). The teeth were extracted after 30 days and prepared due to histological technique.ResultsPulp responses were evaluated in three field including inflammatory cell response, pulp tissue disorganization and restorative dentin formation. There were no differences in histological response of the pulp tissue (P > 0.05).ConclusionBoth adhesive systems showed good biological compatibility.

Effect of bonding application time on the microleakage of Class V sandwich restorations

The aim of this study was to assess the effect of bonding application time on the microleakage of Class V sandwich restorations. Eighty non-carious third molars were randomly divided into 16 groups. Two Class V cavities were prepared on the buccal and lingual surfaces of teeth. Three groups were restored with Fuji II GIC and treated with a total-etch bonding system (Stea/SDI) immediately after insertion, at 7 minutes and 15 minutes after mixing the glass ionomer cements (GICs). Another three groups were restored with Riva Self Cure GIC and treated with the total-etch system identically. The other six groups were subjected to self-etching bonding (Frog/SDI) after GIC placement in an identical procedure. The remaining groups were made using light cure GICs (Fuji II or Riva Light Cure) in conjunction with the total-etch or self-etching systems. Cavities were then restored with composite (Valux plus, 3M/ESPE). Samples were subsequently immersed in 2% methylene blue solution for 48 hours and observed under a stereomicroscope after sectioning. Four-scale grading was used to assess microleakage in occlusal and gingival walls. Data were analysed using Kruskal-Wallis and Mann-Whitney tests. The self-etching bonding system exhibited more microleakage in occlusal margins regardless of time. Over time, microleakage significantly decreased in gingival margins in all self-cure groups except for Riva Self Cure treated with the total-etch system (p < 0.05). Bonding application time had no effect on the microleakage of occlusal margins. However, maturation of GICs induced a decreased microleakage in gingival margins.