Two-step Self-etching Adhesive System Research Articles

Utilizing Laser-Induced Fluorescence to Evaluate the Efficiency of Carbon Dioxide and Diode Lasers in Dentin Sealing after Tooth Preparation: An in-vitro Study.

Adhesive dentistry has made it feasible to design restorations with high aesthetic qualities and little invasiveness. However, the freshly cut dentin after the tooth preparation needs to be sealed to prevent its contaminations, bacterial leakage, and hypersensitivity. Consequently, the immediate dentin sealing (IDS) method has been advised. This study examines different dentinal tubule sealing methods via CO2 laser, diode laser (980-nm) and a two-step self-etch adhesive system applied directly to the fresh cut dentin preceding the placement of the provisional phase. The sealing efficiency of each laser and bond system was evaluated based on the laser-induced fluorescence (LIF) properties and image analysis by scanning electron microscopy. Moreover, the obtained LIF spectra were evaluated using partial least square progression. A two-step adhesive containing a high concentration of S-PRG fillers produced a thick layer that was not perfectly uniform at all sites due to uneven filler distribution in the bond with totally and partially closed dentinal tubules. However, the peaks of the LIF spectra dropped after applying laser because of its sealing effectiveness. Accordingly, CO2 and diode lasers have strong evidence in dentinal tubule sealing and a definitive treatment modality for dentinal hypersensitivity. Moreover, IDS with an adhesive system is superior in occluding dentinal tubules in a biomimetic manner based on its filler content and bioactive properties.

Long-Term Evaluation of Pulp Vitality Preservation in Direct and Indirect Pulp Capping: A Retrospective Clinical Study.

Background: This retrospective clinical study aimed to assess dental pulp tissue reactions to direct and indirect pulp capping after 10 years of follow-up. Methods: A total of 276 permanent teeth with deep carious lesions were evaluated and divided into five groups: Group (1), direct pulp capping with Mineral Trioxide Aggregate cement; Group (2), direct pulp capping with a resin-based glass ionomer; Group (3), direct pulp capping with TheraCal; Group (4), indirect pulp capping with a three-step total-etch adhesive system; and Group (5), indirect pulp capping with a two-step self-etch adhesive system. Results: A 72.5% success rate was achieved overall. A statistically significant difference was found when comparing direct and indirect pulp capping with a success rate of 23.8% and 93.8%, respectively. For direct pulp-capping procedures, the area of pulp exposure was correlated with pulp necrosis (p = 0.035), while bleeding after exposure appeared independent (p = 0.053). Patient age was significantly related to the maintenance of pulp vitality (p = 0.013). A statistically significant correlation between the pulp-capping material and the occurrence of pulp necrosis was discovered (p = 0.017). For the indirect pulp-capping treatments, a significant correlation between patient age (p = 0.021) and the adhesive system (p = 0.019) with pulp necrosis was described. Conclusions: The pulp-capping material, patient age, and the width of the pulp exposure before the procedure should be carefully considered when performing direct pulp-capping treatments. The performance of the etch-and-rinse adhesive systems was superior to the self-etch system during the indirect pulp-capping procedures.

Comparative evaluation of the effect of 37% orthophosphoric acid pre-etching on the microtensile enamel bond strength using universal adhesive and two-step self-etch adhesive systems - An in vitro study.

The significance of enamel etching has been well-researched and established. Limited literature is available comparing the enamel bond strengths of the two-step self-etch adhesive system and the newly introduced universal adhesive (UA) system with prior acid etching. The aim of the study was to evaluate and compare the microtensile bond strength (μTBS) of composite to enamel with and without 37% orthophosphoric acid pre-etching using a recently introduced UA and a two-step self-etch adhesive. This in vitro, experimental study was conducted on 48 extracted human third molar teeth. Two enamel surface fragments were obtained per tooth, polished using 600-grit silicon carbide abrasive paper, and randomly divided into four groups-CLEARFIL SE BOND with and without acid pre-etching and G-Premio Bond with and without acid pre-etching. The samples were etched using 37% phosphoric acid gel for 30 s, followed by the bonding protocol. Composite resin blocks were built incrementally to a thickness of approximately 6 mm, and the restored samples were stored in distilled water for 24 h at 37°C. They were then sectioned, mounted, and subjected to a μTBS test using a universal testing machine. Statistical analysis of the data was performed using one-way ANOVA and Tukey's post hoc test using SPSS software version 22.0. Samples bonded with the UA subjected to prior acid etching protocol demonstrated the highest enamel μTBS. In contrast, those treated with the two-step self-etch adhesive without prior acid etching demonstrated the lowest enamel μTBS. Pre-etching with phosphoric acid significantly increased the enamel bond strength of both bonding agents, with the universal agent showing better results than the two-step adhesive system. Enamel etching with phosphoric acid significantly increases the bond strength of self-etch adhesives. UA with prior acid etching showed the maximum enamel μTBS. Two-step self-etch adhesive without prior acid etching yielded enamel μTBSs unacceptable for long-term, durable bonding.

Uncut Enamel for Optimizing Bonded Composite Restoration on Multiple Diastema Closure Cases

The main advantage of using a minimal invasive strategy concept by uncut enamel technique while doing direct composite restoration is to create a color and translucency close to the natural teeth with long-term bonding durability. Objective: This case report presents an uncut enamel technique for multiple diastema closure cases using direct composite restoration. Case Reports: an 18-year-old male and a 50-year-old female patient complained of diastema in their upper front teeth and requested aesthetic correction. Digital mock-up was made prior to the uncut enamel technique for showing the expected results to the patient and as a guidance for the clinician. Uncut enamel preparation was continued by free-hand restoration technique with a two-step self-etch adhesive system and composite resin application to correct the diastema. The teeth in the first and second cases were followed up after three months and four years, respectively. Conclusion: The uncut enamel preparation, free-hand restoration technique with two-step self-etch adhesive, and digital mock-up are viable options in the multiple diastema closure to re-create natural teeth and optimize bonding durability

EFFECT OF ENDODONTIC IRRIGATION CONTAMINATION ON DENTIN FOR ADHESIVE RESTORATIONS

This study aimed to evaluate if 2.5% sodium hypochlorite compromises the adhesion of bonding materials. The factors in the study were the irrigation solutions in two levels: 2.5% sodium hypochlorite and saline solution; and the adhesive systems used in three levels: three-step adhesive, universal adhesive, and two-step self-etch adhesive systems. The answer variable used was the microshear bond strength obtained through a universal testing machine and fracture mode. Six groups were obtained (n=10) : Etch-and-rinse/Saline (saline solution + 3-step adhesive system - Scotchbond Multipurpose, 3M ESPE); Universal/saline (saline solution + universal adhesive system – Prime&Bond,); Self-etch/saline (saline solution + 2-step self-etch adhesive systems - Clearfil SE Bond); Etch-and-rinse/Hypo (sodium hypochlorite 2,5% + 3-step adhesive system - Scotchbond Multiuso); Universal/Hypo (sodium hypochlorite 2,5% + universal adhesive system – Prime&Bond); Self-etch/Hypo (sodium hypochlorite 2,5% + 2-step self-etch adhesive system - Clearfil Se Bond). The specimens were obtained from 60 healthy bovine incisors. The crowns were separated from the roots, and the regularization of the buccal surface was performed. The groups received saline solution and 2.5% sodium hypochlorite for 30 minutes, respectively. A matrix of 1mm and 3mm oh height was stabilized by Scotch tape to obtain the resin sticks. Afterward, the bond strength test was performed in a universal testing machine at 1mm/min speed. The data were analyzed with normality Shapiro-Wilk, two-way ANOVA, and Tukey’s tests (p<0.001). Etch-and-rinse and Self-etch adhesives presented the highest bond strength values after irrigation with saline solution and 2.5% sodium hypochlorite, respectively (P < 0.01). The irrigation with 2.5% sodium hypochlorite decreased the bond strength values of Etch-and-rinse and Universal (P < 0.01). On the other hand, 2.5% sodium hypochlorite improved the bond strength values of Self-etch (P < 0.01). In conclusion, 2.5% sodium hypochlorite negatively impacted the bond strength of Etch-and-rinse and Universal but improved the adhesion of Self-etch.

Clinical effectiveness of direct resin composite restorations bonded using one-step or two-step self-etch adhesive systems: A three-year multicenter study

The purpose of this multicenter clinical study was to compare the mid-term clinical effectiveness of direct resin composite restorations using one-step or two-step self-etch adhesives (1-SEAs or 2-SEAs). In total, 352 restorations of class I-V cavities and non-carious cervical lesions in vital teeth (1-SEAs; 52 cases, 2-SEAs; 300 cases) were placed at nine university hospitals and evaluated according to the modified USPHS criteria at baseline, and after 1, 2, and 3 years. The recall rates were 86.6% (1 year), 80.1% (2 years), and 62.2% (3 years). Two restorations failed due to fracture during the follow-up, and there was no significant difference in survival rates between 1-SEAs (97.6%) and 2-SEAs (99.4%). However, 2-SEAs exhibited significantly lower occurrences of discoloration, marginal discoloration, fracture, and plaque retention. Moreover, the subjects reported a significantly lower postoperative hypersensitivity and higher overall satisfaction at all evaluation periods if 2-SEAs were used.

Evaluation of the Bond Strength of Different Pulp Capping Materials to Dental Adhesive Systems: An In Vitro Study

Aim: To evaluate the bond strengths of pulp capping materials (Dycal, ProRoot MTA, Biodentine, TheraCal LC, Calcimol LC, and ApaCal ART) and different adhesive systems (Gluma 2 Bond, Clearfil SE Protect, Gluma Self Etch, Clearfil S 3 Bond Plus, Gluma Bond Universal, Clearfil S 3 Bond Universal). Materials and Methods: Two hundred fifty-two acrylic blocks were prepared in which cylindrical cavities of 4 × 2 mm 3 were formed. Pulp capping materials were placed in the cavities. Different adhesive systems were applied to each pulp capping material group. After applying the composite resin, the shear bond strength (SBS) values of the specimens were determined in the Instron test device. Fracture types were evaluated using a stereomicroscope and a scanning electron microscope. Data were analyzed by Shapiro–Wilk’s and Kruskal–Wallis H test. Results: There is a statistically significant difference between pulp capping materials in terms of SBS values ( P < .05). Dycal’s SBS was found significantly lower than other materials, and the highest bond strength was observed in Calcimol LC material. Although there is no statistically significant difference ( P > .05) between the adhesive agent groups in terms of SBS, Gluma 2 Bond showed the highest bond strength value. Conclusion: In traditional pulp capping materials such as Dycal, MTA, and Biodentine, using a two-step self-etch adhesive system can result in higher bond strength values. In resin-based TheraCal LC,, ApaCal ART, and Calcimol LC materials, it may be recommended to use a two-step etch and rinse adhesive system.

Effect of double-layer application on the early enamel bond strength of universal adhesives.

The present study aimed to investigate the changes in the enamel bond strengths of universal adhesives in the early phase of specimen creation and evaluate the effect of double-layer application on enamel bond effectiveness using different etching modes. Four universal adhesives, namely Clearfil Universal Bond Quick, G-Premio Bond, Scotchbond Universal, and Tokuyama Universal Bond, were used. Clearfil SE Bond two-step self-etch adhesive system was used as a comparison. Fifteen specimens per group were used for determining the shear bond strength (SBS) to bovine enamel in the etch-and-rinse or self-etch mode. The adhesive was applied to specimens in accordance with the manufacturers' instructions (single-layer application), or the adhesive was applied twice (double-layer application). The bonded specimens were stored in distilled water at 37°C for 5min or 1, 6, 12, or 24h before SBS testing. The flexural properties of the resin composite Clearfil AP-X were measured for the same storage periods. All universal adhesives exhibited increased SBS values with prolonged storage periods regardless of the application technique or etching mode used. Double-layer application was associated with higher SBS values than single-layer application for most universal adhesives over the same storage period. Phosphoric acid pre-etching and double-layer application of universal adhesives resulted in increased enamel bond strength in the early phase of specimen bonding. Care should be taken when using universal adhesives in the self-etch mode for enamel bonding because the enamel adhesion is sensitive to the duration after filling.

Micro-shear bond strength of adhesives with different degrees of acidity: Effect on sound and artificially hypermineralized dentin.

This study evaluates the bond strength of four self-etching adhesive systems with different acidity levels in normal and artificially hypermineralized dentin substrate. Healthy human molars were divided into groups: normal dentin-N (n = 36) and artificially hypermineralized dentin-H (n = 36). Self-etching adhesive systems Clearfil S3 Bond (n = 9), Optibond All in One (n = 9), Clearfil SE Bond (n = 9), and Adhese (n = 9) were used for both the N and H groups. Transparent cylindrical matrices were positioned on the treated dentin surfaces, filled with composite resin, and light-cured for 40 s. After the transparent cylindrical matrices were removed, the specimens were stored for 24 hr in a humid environment at 37°C and were subjected to a micro-shear bond strength test. For each group, a specimen was prepared and evaluated in scanning electron microscope for adhesive interface observation. Normality was confirmed and the two-way analysis of variance and Games-Howell post-tests were conducted (α = .05). The data demonstrated an interaction between the adhesive system and type of dentin substrate (p < .01). For normal dentin, all adhesive systems assessed were adequate; however, in the hypermineralized dentin, the Clearfil SE Bond two-step self-etching adhesive system with mild pH presented the highest immediate bond strength. There was a predominance of adhesive failures for all adhesive systems in the different dentin substrates evaluated. It was concluded that the self-etching adhesive systems evaluated were efficient for both substrates, and for the hypermineralized dentin, the Clearfil SE Bond presented a higher bond strength value.

Evaluation of alternative photoinitiator systems in two-step self-etch adhesive systems

ObjectiveThe aim of this study was to evaluate the effect of different photoinitiator systems on the cell viability and physico-chemical properties of an experimental adhesive resin of a two-step self-etch adhesive system. MethodsEight photoinitiators and coinitiators were evaluated, camphorquinone (CQ); ethyl-dimethylamino benzoate (EDAB); diphenyliodonium hexafluorophosphate (DPIHFP); 1,3-benzodioxole (BDO); piperonyl alcohol (AP); 1,3-diethyl-2-thiobarbituric acid (TBA); bisphenyl phosphinic oxide (BAPO); and diphenyl phosphinic oxide (TPO). Seven experimental adhesive resins (Bis-GMA:TEGDMA – 1:1 by wt%) were formulated by varying the initiation systems: RCQ+EDAB (control), RCQ+EDAB+DPHFP, RCQ+BDO, RCQ+AP, RCQ+TBA, RBAPO and RTPO. The cell viability of the different photoinitiators in their isolated form and after being incorporated into the adhesive resins was evaluated using the MTT assay. The degree of conversion within the hybrid layer (DC in situ) was evaluated by micro-Raman spectroscopy; the polymerization kinetics, by FTIR spectroscopy. The water sorption (Wsp) and solubility (Wsl) were calculated by using percentage of gain and loss of mass. Data were analyzed using One-way ANOVA and Kruskal-Wallis tests (α=0.05). ResultsWhen evaluated in their isolated form, the DPIHFP was considered cytotoxic in all concentrations evaluated. When incorporated into and adhesive resin, RCQ+TBA presented higher cell viability values than control and the highest values of DC in situ (p<0.05). Additionally, the use of CQ+TBA showed a higher cell viability when compared with the conventional CQ+EDAB system. SignificanceThe pair CQ+TBA could be potentially useful in the development of materials with improved biocompatibility.

In Vitro Effect of Temperature on Dentin Bond Strength of Universal Adhesive Systems

The aim of this study was to evaluate the shear bond strength (SBS) of two universal adhesives (Universal Single Bond and All Bond Universal) and a two-step self-etch adhesive system (Clearfil SE Bond) to dentine at various temperatures. Materials and Methods: One hundred and twenty dentin specimens were divided randomly to 12 groups, according to adhesive systems (Universal Single Bond and All Bond Universal, Clearfil SE Bond) and temperature ( 4ºC, 20 ºC, 36ºC, 55ºC) used. Dentin specimens were prepared (n :10, adhesives were applied, and composite cylinders were polymerized. Statistical analysis of the SBS data was performed using Two-way analysis of variance (ANOVA) and Tukey’s Honestly Significant Differences post-hoc test. Results: The Clearfil SE Bond was shown to have higher SBS than the universal adhesives at all temperatures; however, there was no statistically significant difference (P&gt;0.05). In both groups, the lowest SBS values were observed in the samples at 4°C while the highest SBS values were observed in the samples at 55°C. In this case, there was a statistically significant difference (P&lt;0.05). Conclusions: The results suggest that the effectiveness of an adhesive may increase if it is preheated at 36°C or above before use instead of being used immediately after removal from the refrigerator or at room temperature.

Effect of zinc chloride added to self-etching primer on bond strength to caries-affected dentin and chemical-physical-mechanical properties of adhesives

The aim of this in vitro study was to evaluate the effect over time of zinc chloride (ZnCl2) incorporated into the primer of a two-step self-etching adhesive system (Clearfil SE Bond, Kuraray - SE) on long-term microtensile bond strength (μTBS) to caries-affected dentin (CAD), and on flexural strength (FS) and conversion degree (CD) of the adhesive. First, the CD of SE with and without 2% (wt) ZnCl2 solution was evaluated by Fourier transform infrared spectroscopy (FTIR). Then, beam-shaped samples (7 mm × 2 mm x 1 mm) were prepared with the SE primer containing the ZnCl2 solution, to perform flexural strength (FS) tests. For μTBS testing purposes, CAD surfaces were randomly divided into two groups, according to the presence of ZnCl2 powder (2 wt%) incorporated into the adhesive system (ZnCl2), or its absence (NT). An additional group consisting of dentin pretreated with a 2% chlorhexidine digluconate (CHX) solution was proposed as a positive control (n = 10). A two-step self-etching system (SE) was applied following the manufacturer's instructions, and restorations of composite resin were built up on the dentin. After 24 h, the resin-dentin blocks were sectioned into specimens that were submitted to μTBS testing immediately following, or after 12 months of water storage (WS). Both μTBS and FS tests were performed using a universal testing machine (0.5 mm/min). FS and CD data were submitted to the Student t-test, and μTBS data were submitted to two-way ANOVA and Tukey's test (α = 0.05). ZnCl2 incorporation had no statistically significant influence on flexural strength (p = 0.88) or conversion degree (p = 566). Regarding μTBS, no significant effect of the double interaction of “dentin treatment” versus “WS period” (p = 0.546) was observed. The bond strength was not affected by the WS period (p = 0.805). The highest mean bond strength was observed for the NT group, which did not differ from the ZnCl2 group. The lowest mean bond strength was observed for the CHX group, which differed statistically from the NT group (p = 0.053). It was concluded that incorporation of ZnCl2 into the SE self-etching primer did not interfere in the bond strength of caries-affected dentin, in regard to failure mode, flexural strength or CD, and had no other beneficial effects.

Evaluation of experimental calcium-containing primer in adhesive system on micro-tensile bond strength and acid resistance.

Modern adhesive systems have been developed for enhanced mechanical and antibacterial properties; however, no such systems contain a calcium source to enhance bond strength. Therefore, we evaluated the effect of an experimental calcium-containing primer (10 wt% CaCl2) in two-step self-etching adhesive systems on micro-tensile bond strength (μ-TBS) and acid resistance in dentin adhesive interface observations after acid-challenge using scanning electron microscopy. Using two types of primers and bonding agents (Clearfil SE Bond primer (SEP), experimental calcium-containing primer (CaP), Clearfil SE Bond (SEB), and Clearfil Protect Bond), we prepared four experimental groups. The μ-TBS of CaP-SEB did not differ from that of SEP-SEB. Meanwhile, the CaP groups showed a thicker acid-base resistance zone. Thus, two-step self-etching adhesive system composed of experimental calciumcontaining primer can be used as an adhesive system with high acid resistance and acceptable bond strength.

Influência do pré-condicionamento ácido em dentina na resistência de união imediata de sistemas adesivos autocondicionantes de dois passos

Objetivo: Avaliar a influência do pré-condicionamento da dentina com ácido fosfórico sobre a resistência de união de dois sistemas adesivos autocondicionantes de dois passos.&#x0D; Métodos: Foram utilizados 32 incisivos bovinos, divididos aleatoriamente em 4 grupos. Os grupos receberam a aplicação dos sistemas adesivos autocondicionantesClearFil SE Bond (GCL) ou AdheSE (GAD). Dois grupos, GADpa e GCLpa, receberam, antes da aplicação do primer, o condicionamento com ácido fosfórico. Em cada dente foram confeccionados seis restaurações cilíndricas com área adesiva de 0,88 (± 0,03) mm2. Após 24 horas, os dentes foram submetidos ao ensaio de microcisalhamento, em uma máquina de ensaios universal, com uma velocidade de 1mm/min. A análise dos dados foi realizada com ANOVA de dois fatores a um nível de significância de 5%.&#x0D; Resultados:Os valores médios de resistência de união variaram entre 16,25 e 21,71 MPa, entretanto não houve diferença estatisticamente significativa entre todos os grupos avaliados (p&gt;0,05).&#x0D; Conclusão: O condicionamento ácido da dentina não influenciou a resistência de união imediata dos dois sistemas adesivos autocondicionantes de dois passos.

Effects of caffeic acid phenethyl ester application on dentin MMP-2, stability of bond strength and failure mode of total-etch and self-etch adhesive systems

ObjectiveInvestigate the long-term effect of dentin pretreatment with 0.05 or 0.1% caffeic acid phenethyl ester (CAPE) on (1) bond strength of resin composite to dentin by a three-step etch-and-rinse (Adper Scotchbond Multipurpose/ ASB) or a two-step self-etch adhesive system (Clearfil SE Bond/ CSE), (2) their fracture mode, (3) the micromorphological features of the hybrid layer formed; and (4) the level of MMP-2 in dentin (after application, using a correlative immunoexpression/quantification approach). DesignComposite resin blocks were fabricated on 48 third molars (n = 6), according to the type of adhesive and treatment (control, CAPE 0.05% and CAPE 0.1%). Slices were obtained for scanning electron microscopy (SEM) evaluation, and sticks were fabricated for microtensile tests (24 h and 1 year). Aliquots of dentin powder were distributed (n = 12) according to the treatment and the MMP-2 concentration was determined by ELISA. ResultsTukey test showed that ASB groups presented higher BS in 24 h than CSE groups. ASB presented a reduction in BS values after 1-year. ASB and CSE presented no significant differences in BS after 1-year. CAPE had no effect on BS for both adhesive systems. The predominant failure mode for the ASB groups were adhesive; when 0.1% CAPE was applied there was a predominance of mixed fractures. Regarding the CSE group, 0.05% CAPE led to more adhesive failures, and the 0.1% concentration resulted in a higher number of cohesive failures in dentin. Higher MMP-2 concentrations were detected for the groups that did not undergo demineralization treatment, and the lowest values for the ASB groups treated with CAPE. SEM analysis showed no influence of pretreatment with CAPE. ConclusionsCAPE did not influence the BS of the adhesives tested, or the micromorphology of the hybrid layer, irrespective of concentration or storage time. CAPE affected the fracture pattern at 24 h, depending on the concentration and the adhesive system used. Immunoassay analysis showed that CAPE 0.1% reduced the MMP-2 concentration in the ASB adhesive without affecting bond strength to dentin.

Micro-CT assessment of comparative radiopacity of adhesive/composite materials in a cylindrical cavity

This study was performed to evaluate the comparative radiopacity of adhesive/resin composite materials in cylindrical cavities using micro-computed X-ray tomography (μCT). The two-step self-etch adhesive systems, Clearfil SE Bond (SE) and FL-Bond II (FL), and flowable resin composites, Beautifil Flow F10 (BF) and Clearfil Majesty ES Flow High (MJ), were used. The radiopacity of bovine tooth structures and restorative materials was measured by μCT. In addition, cylindrical cavities prepared in bovine teeth were restored with the following adhesive/composite combinations: SE-BF, SE-MJ, FL-BF, and FL-MJ. The mean gray values of the composite restorations were calculated. The threshold values of the μCT images were evaluated using the Otsu's thresholding method. The current results show that the comparative radiopacity of the materials and tooth structure varied, which affected distinguishing the μCT images of the composite restorations in the cylindrical cavity. The proper combination of restorative materials should be considered when conducting in vitro μCT assessments of composite restorations.

Evaluation of fracture resistance of premolars restored with packable composite resin using different types of adhesive systems

Purpose The aim of this study was to evaluate the fracture resistance of human extracted premolars restored with packable composite resin by using three types of adhesive systems: two-step etch-and-rinse system, two-step self-etch primer adhesive system, and one-step self-etch adhesive system. Materials and methods Fifty sound maxillary second premolars were selected. Forty specimens received class II mesio-occluso-distal cavities with a 2 ± 0.2 mm pulpal depth, 1.5 ± 0.2 mm gingival width, 2 ± 0.2 mm axial height, and parallel proximal walls with 3 ± 0.2 mm buccolingual width. All samples were divided into five groups (10 each): group I: positive control group (intact teeth), group II: negative control group (prepared unrestored), groups III, IV, and V: prepared and restored with Filtek Z350 XT packable composite resin by using three types of adhesive systems; Adper Single Bond, Clearfil liner Bond F, Single Bond Universal Adhesives respectively. After thermocycling, Specimens were subjected to compressive axial loading, and were tested individually in a universal testing machine. Peak loads at fracture were recorded. Statistical analysis was performed using SPSS, version 20.0. Results All groups were significantly higher than prepared but unrestored teeth with no significant difference was recorded between the three types of adhesives. Conclusion Restoring with packable composite using adhesive system had improved the fracture resistance of teeth subjected to class II mesio-occluso-distal preparations. Using the adhesive systems, insignificantly affect fracture resistance of premolars.

Influence of dentin pretreatment with 2.5% titanium tetrafluoride on inhibiting caries at the tooth-restoration interface in situ

ObjectiveInvestigate the effects of dentin pretreatment with 2.5% titanium tetrafluoride (TiF4) aqueous solution followed by two-step self-etching (CLE/Clearfil SE Bond) and one-step self-etching adhesive systems (SBU/Single Bond Universal) on carious lesion inhibition at the tooth-restoration interface using an in situ model. DesignSixty-four cavities at the enamel-dentin junction of dental fragments were randomly distributed according to groups (n=16): 1) TiF4+CLE; 2) TiF4+SBU; 3) CLE; 4) SBU. Cavities were restored using resin composite, and placed in intraoral palatal devices used by 16 volunteers for 21days, to induce caries formation in situ. The fragments were then ground-flat to perform Knoop microhardness tests. Nine indentations were performed on each enamel and dentin substrate, subjacent to the restoration. Analysis of variance and Tukey’s test were applied. ResultsEnamel: groups receiving TiF4 dentin pretreatment (regardless of adhesive system and tooth-restoration interface distance) presented higher hardness means at a depth of 25μm from the outer tooth surface (p<0.0001). Dentin: groups receiving CLE presented higher means when applying TiF4 pretreatment, whereas groups restored with SBU presented higher means without pretreatment (p=0.0003). ConclusionsDentin pretreatment with TiF4 inhibited demineralization of the enamel interface in situ, regardless of the adhesive, and TiF4 pretreatment followed by CLE application showed higher potential for inhibiting dentin demineralization at the interface.

Resin-dentin bond stability and physical characterization of a two-step self-etching adhesive system associated with TiF4

ObjectivesTo evaluate the bond strength to superficial (SD) and deep (DD) dentin after the use of 2.5% (T2.5%) or 4% (T4%) titanium tetrafluoride (TiF4) in aqueous solution as a dentin pretreatment, or when incorporated into the primer (T2.5%P and T4%P) of an adhesive system (Clearfil SE Bond/CL). Degree of conversion (DC), particle size (PS), polydispersity index (PI) and zeta potential (ZP) of the solutions were evaluated. MethodsFifty molars were sectioned longitudinally to obtain two slices of each tooth, which were demarcated into SD and DD. Treatments were applied (n=10): CL; T2.5%; T4%; T2.5%P; T4%P. After 24h or 180days storage, microshear bond strength tests were performed. The DC values of T2.5%P and T4%P were evaluated by FTIR. PS, PI and ZP were measured using dynamic light scattering. ResultsAnalysis of mixed models showed significant effect of concentration of TiF4 * solution * storage time (p=0.0075). There were higher bond strength values in SD than in DD (p=0.0105) for all treatments in both times. The failure mode showed adhesive failures in the majority of groups, irrespective of depth and time (p=0.3746). The bond strength values were not affected by treatments. Lower average particle size was observed for T2.5%P and T4%P at baseline. T2.5% and T4% showed a trend towards agglomeration. SignificanceHigher bond strength values were achieved at SD for all treatments and times. The failure modes observed were adhesive. TiF4 incorporation did not affect DC. T2.5%P and T4%P presented excellent stability over time.

Titanium tetrafluoride incorporated into a two-step self-etching adhesive system: physico-mechanical characterization and bonding stability.

To evaluate the influence of TiF4 incorporated into the primer (P) or bond (B) of a self-etching adhesive system on long-term dentin bonding, and evaluate the physico-mechanical properties of TiF4-containing adhesives. Dentin surfaces received the following treatments (n = 8): CL (Clearfil SE Bond); TiF4CL (dentin pretreatment with TiF4 aqueous solution + CL); TiF4P (TiF4 incorporated into the P); TiF4B (TiF4 incorporated into the B). Microtensile bond strength (µTBS) and failure mode evaluations were performed after 24h, 6 months and one year, respectively. Degree of conversion (DC) and flexural strength (FS) were evaluated to determine whether TiF4 influenced adhesive properties. Particle size (PS), polydispersity index (PI) and zeta potential (ZP) of TiF4-containing adhesives were measured using dynamic light scattering. Two-way ANOVA for repeated measures was applied to µTBS data, and one-way ANOVA and Tukey tests to DC and FS results. There was no difference in µTBS among the groups (p = 0.818) regardless of time; the µTBS in each group was not significantly affected over time (p = 0.061). TiF4P and TiF4B significantly affected FS (p = 0.004). The DC for TiF4P was not significantly different from that of CL, and higher than that of TiF4B. Lower average particle size was observed for TiF4P at baseline. TiF4 aqueous solution showed a tendency to agglomerate. TiF4-containing adhesives did not influence µTBS or failure mode to dentin over time, although FS and DC were affected, especially when TiF4 was incorporated into the B. TiF4P presented excellent stability over time.