Bora Ozturk

Effect of NaOCl on Bond Strengths of Bonding Agents to Pulp Chamber Lateral Walls

The objective of this study was to evaluate the effects of 5% NaOCl on bond strengths of four bonding systems-Clearfil SE Bond, Prompt L-Pop, Prime&Bond NT, and Scotchbond Multi Purpose Plus-to pulp chamber mesial walls. Forty mandibular third molar teeth were used in the study. The pulp chambers of the first 20 teeth were restored with bonding agents and composite resins after 5% NaOCl irrigation, and the remaining teeth were restored without 5% NaOCl treatment. Each bonding group had five teeth. Three rectangular thin sticks (1+/-0.03 mm) were obtained from the mesial wall of restored pulp chambers by horizontal sectioning. In general, NaOCl application decreased the bond strength values of the bonding agents. Both Clearfil SE Bond and Prompt L-Pop without NaOCL showed higher bond strength values than the other bonding groups. In NaOCl-applied groups, Clearfil SE Bond had the highest bond strength. It can be concluded that self-etching bonding systems are more successful than the other systems in bonding to pulp chamber dentinal wall and that NaOCl reduces bond strength.

The Effect of Bleaching Agents on the Color Stability of Ceromer and Porcelain Restorative Materials In Vitro

PURPOSE The aim of this in vitro study was to determine the color changes of five different restorative materials after exposing these materials to two different home bleaching agents. METHODS This study applied bleaching agents to an ultralow-fusing porcelain, a low-fusing porcelain, two types of heat-pressed glass ceramics, and a ceromer. A total of 24 disc-shaped specimens were fabricated (with a diameter of 10 mm and a thickness of 2 mm) from each material (n=12). The initial color measurements were taken with a spectrophotometer. The first set of specimens were bleached with 10% hydrogen peroxide (HP) for one hour daily for 10 days. The other set of specimens were bleached with 10% carbamide peroxide (CP) bleaching gel for eight hours daily for 14 days. Data were analyzed with the one-way analysis of variance and Kruskal-Wallis statistical test. The difference in the prebleaching and postbleaching color of each material was considered to be statistically significant at p < 0.05. RESULTS The study found a statistically significant difference among the color changes of the test groups after exposing them to both bleaching agents (p<0.05). Appreciable color change was observed in the Estenia (ΔE=3.99) specimens that were bleached with the HP, and noticeable color changes were observed in the Estenia (ΔE=1.89) and IPS Empress 2 (ΔE=1.66) groups when they were treated with the CP. CONCLUSIONS Restorations (especially polymer-containing restorative materials) should be protected before any bleaching procedure due to the high risk of color change.

Elution of monomer from different bulk fill dental composite resins

OBJECTIVE The purpose of this study was to evaluate the elution of Bis-GMA, TEGDMA, HEMA, and Bis-EMA monomers from six bulk fill composite resins over four different time periods, using HPLC. METHODS Six different composite resin materials were used in the present study: Tetric Evo Ceram Bulk Fill (Ivoclar Vivadent, Amherst, NY), X-tra Fill (VOCO, Cuxhaven, Germany), Sonic Fill (Kerr, Orange, CA, USA), Filtek Bulk Fill (3M ESPE Dental Product, St. Paul, MN), SDR (Dentsply, Konstanz, Germany), EQUIA (GC America INC, Alsip, IL). The samples (4mm thickness, 5mm diameter) were prepared and polymerized for 20s with a light emitted diode unit. After fabrication, each sample was immediately immersed in 75wt% ethanol/water solution used as extraction fluid and stored in the amber colored bottles at room temperature. Ethanol/water samples were taken (0.5mL) at predefined time intervals:10m (T1), 1h (T2), 24h (T3) and 30 days (T4). These samples were analyzed by HPLC. The obtained data were analyzed with one-way ANOVA and Tukey HSD at significance level of p<0.05. RESULTS Amount of eluted Bis-EMA and Bis-GMA from Tetric Evo Ceram Bulk Fill and amount of eluted TEGDMA and HEMA from X-tra Fill higher than others composites (p<0.05). SIGNIFICANCE Residual monomers were eluted from bulk fill composite resins in all time periods and the amount of eluted monomers was increased with time.

Effects of staining solutions on the discoloration of orthodontic adhesives: An in-vitro study

INTRODUCTION Our aim was to evaluate the effects of staining solutions on the discoloration of orthodontic adhesives. METHODS Six orthodontic adhesives were investigated (Transbond XT [3M Unitek, Monrovia, Calif, USA], Heliosit Orthodontic [Ivoclar Vivadent, Liectenstein], Light Bond [Reliance Orthodontic Products, Itasca, IL, USA], Bisco Ortho [Bisco, Schamburg, IL, USA], Quick Cure [Reliance Orthodontic Products, Itasca, IL, USA], and Filtek Supreme XT [3M ESPE, St Paul, Minn, USA]), and 5 beverages (tea, cola, coffee, red wine, and yogurt). Sixty specimens were prepared. Five specimens from each group were stored in each of the 5 staining solutions. The 5 remaining specimens from each group served as the controls and were stored in distilled water. The specimens were immersed in staining solutions and water at 37°C ± 1°C for 5 days. The test period was 25 days. Before and after the test period, color measurements were carried out with a spectrophotometer, and color changes (ΔE∗) were calculated. Statistical differences were evaluated by using analysis of variance (ANOVA) and the Tukey HSD tests. RESULTS Adhesive materials, staining agents, and their interactions were found to play statistically significant roles (P < 0.001) in color changes. Among the adhesive materials, the Light Bond water control group consistently showed the lowest ΔE∗ value for all materials, and the Filtek Supreme XT group showed the highest ΔE∗ value for all materials. After the in-vitro experimental process for staining solutions and water, unsatisfactory color stability was observed for the conventional adhesive systems except for Light Bond, Transbond XT, and Bisco Ortho water control group (ΔE∗ > 3.7), respectively. CONCLUSIONS In esthetically critical areas, discoloration of adhesive materials for fixed orthodontics can cause patient dissatisfaction. Orthodontic composites will discolor from staining beverages during their lifespan.

Evaluation of micro-tensile bond strength of caries-affected human dentine after three different caries removal techniques

OBJECTIVE This study evaluated the effect that different techniques for removing dental caries had on the strength of the microtensile bond to caries-affected human dentine created by three bonding agents. MATERIALS AND METHODS Forty-five human molar teeth containing carious lesions were randomly divided into three groups according to the technique that would be used to remove the caries: a conventional bur, an Er:YAG laser or a chemo-mechanical Carisolv(®) gel (n=15). Next, each of the three removal-technique groups was divided into three subgroups according to the bonding agents that would be used: Clearfil(®) SE Bond, G-Bond(®), or Adper(®) Single Bond 2 (n=5). Three 1mm(2) stick-shaped microtensile specimens from each tooth were prepared with a slow-speed diamond saw sectioning machine fitted with a diamond-rim blade (n=15 specimens). For each removal technique one dentine sample was analysed using scanning electron microscopy. RESULTS There were statistically significant differences in the resulting tensile strength of the bond among the techniques used to remove the caries and there were also statistically significant differences in the strength of the bond among the adhesive systems used. The etch-and-rinse adhesive system was the most affected by the technique used to remove the caries; of the three techniques tested, the chemo-mechanical removal technique worked best with the two-step self etch adhesive system. CONCLUSION The bond strength values of the etch-and-rinse adhesive system were affected by the caries removal techniques used in the present study. However, in the one- and two-step self etch adhesive systems, bond strength values were not affected by the caries removal techniques applied. While a chemo-mechanical caries removal technique, similar to Carisolv(®), may be suggested with self etch adhesive systems, in caries removal techniques with laser, etch-and-rinse systems might be preferred. CLINICAL SIGNIFICANCE Caries removal methods may lead to differences in the characteristics of dentine surface. Dentine ultra structure generally affects the bonding of adhesive materials commonly used in restorative dentistry. Whereas etch-and-rinse system, like the ones used in the present study, are affected by these changes, the self etch systems are not affected. Hence, clinicians may opt for caries removal methods and systems appropriate for each patient and practice.

Influence of different tooth types on the bond strength of two orthodontic adhesive systems

The aim of this investigation was to evaluate the effects of different tooth types on the shear bond strength (SBS) of two orthodontic resin adhesive systems in vitro. Two hundred extracted sound human teeth were used in the study. Ten teeth of each tooth type were the mounted in acrylic resin leaving the buccal surface of the crowns parallel to the base of the moulds. In each experimental group, the adhesives (Transbond XT™ and Light Bond™) were applied to the etched enamel surfaces. The orthodontic composite resins were then applied to the surface in cylindrical-shaped plastic matrices. For SBS testing, a force transducer (Ultradent™) was applied at a crosshead speed of 1 mm/minute at the interface between the tooth and composite until failure occurred. Data were analysed using two-way analysis of variance (ANOVA), Kruskal–Wallis one-way ANOVA, a Bonferroni adjusted Mann–Whitney U-test, and an independent t-test. Generally, it was found that tooth type had a significant effect on SBS (P < 0.05) with Light Bond™ showing a higher SBS than Transbond XT™ (P < 0.05). The highest bond strengths were observed for the upper central incisor and lower molars with Light Bond™ (P < 0.05) and the lowest mean bond strengths for the upper molars and lower canine with Transbond XT™ (P <0.05). The results demonstrated that enamel SBS was significantly altered by both tooth type and adhesive system. Thus, the findings of this study confirm that enamel bond strength is not uniform for all teeth. These results may also explain the variability in the enamel-bonding efficacy of adhesives.

Bond strength of aged lingual retainers

Introduction: The purpose of this study was to examine the tensile bond strength (TBS) of two different lingual retainer (LR) composite systems and three LR wires after they were aged by loadcycling and thermocycling. Materials and Methods: A 15 mm length of wire was bonded to the lingual surfaces of pairs of human incisors using two bonding techniques. Seventy-two pairs of incisors were placed into six groups, and loadcycling (50,000 times) and thermocycling (10,000 times) were performed. The failure characteristics examined included the maximum force for debonding and the site of failure. The adhesive remnant index scores were calculated. Data were compared by two-way analysis of variance and Tukey highly significant difference analysis. Results: All groups generally showed statistically significant differences in TBS score (P < 0.05). For each group, the highest average TBS score (P < 0.05) was obtained from a Transbond LR + Remalloy LR combination. The main failure type was a mixed failure. Conclusions: Retainer wire and composite combinations had significant differences. One of the best selection criteria for LRs is the determination of the bond strength needs of a case.

Effect of caries removal techniques on bond strength to caries affected dentin on gingival wall: AFM observation of dentinal surface

Abstract Objective: The purpose of this study was to evaluate the effect of different caries removal techniques on the bond strength of two adhesive systems. Materials and Methods: Seventy human molar teeth that had proximal carious lesions were randomly divided into four groups according to the technique used to remove the caries: a conventional steel bur, an Er:YAG laser, a chemomechanical Carisolv® gel, and air polishing. The groups were then divided into two subgroups according to the adhesives used: Clearfil S3 (Kuraray Co., Ltd, Tokyo, Japan) and Adper SE Plus (3 M ESPE, St Paul, MN, USA). The enamel and superficial dentin of the crown was flattened and caries were removed using different methods. Teeth were restored with composite and three 1 mm2 stick-shaped microtensile specimens were prepared from each tooth. For each removal technique, the surface roughness of one dentin sample was analyzed using atomic force microscopy (AFM). The microtensile bond strength data were then analyzed using a two-way ANOVA, Kruskal–Wallis and Mann–Whitney U tests, and multiple comparison tests (p = 0.05). Results: The two-way ANOVA showed that the effects of the cavity preparation techniques and adhesive systems and their interaction were statistically significant (p < 0.05). The μTBS values were highest when bonding with Adper SE Plus to cavities prepared with the steel bur (37.20 ± 11.65 MPa) and lowest when bonding with Clearfil S3 Bond to cavities prepared with the Er:YAG laser (16.74 ± 6.95 MPa). Conclusion: The caries removal techniques affected the bond strength values of the self-etch adhesive systems.

Effect of Erbium:yttrium aluminum garnet laser on bond strength of a total-etch adhesive system to caries-affected dentin on gingival wall

Purpose: To assess the effect of the erbium:yttrium aluminum garnet (Er:YAG) laser on bond strength of a total-etch adhesive system to the caries-affected dentin on the gingival wall. Materials and Methods: Ten human molars with proximal carious lesions were randomly divided into two groups. In the first group, the carious dentin was removed with a bur, whereas in the second group it was removed with the Er:YAG laser. Carious lesions were excavated with one of these two techniques until laser fluorescence values decreased to 15 in the center of the lesions. The teeth were then restored with a total-etch adhesive system (Adper Single Bond 2) and composite resin (Filtek Z250). Five teeth from each group were sectioned to obtain 1 mm2 stick-shaped microtensile specimens from each tooth. Twenty-five specimens were obtained for each group with using this technique. The data were analyzed in independent-samples t-test (α = 0.05). For each removal technique, one sample was analyzed using scanning electron microscopy. Results: No statistically significant differences were found between the bond strength of the Er:YAG laser and the bur-treated groups (P > 0.05). Conclusion: The Er:YAG laser treatment did not negatively affect the bonding performance of the total-etch adhesive system to caries-affected dentin on the gingival wall.

Effect of a re-wetting agent on bond strength of an adhesive to primary and permanent teeth dentin after different etching techniques

OBJECTIVE This study investigated the effect of a re-wetting agent on the microtensile bond strengths (mTBS) of primary and permanent dentin after acid or laser etching. MATERIALS AND METHODS Twelve permanent and 12 primary molar teeth were ground to expose an occlusal dentin surface. Each group teeth were randomly divided into groups; I-II: 37% phosphoric acid etching with/without re-wetting agent, III-IV: Erbium: Yttrium aluminium garnet laser etching with/without re-wetting agent. An etch-and-rinse adhesive was used, and vertical sticks were obtained for the microtensile test. RESULTS mTBS of permanent teeth was higher than that of primary teeth (P < 0.05). Re-wetting agent groups were similar with control groups in both etching groups in the permanent teeth (P > 0.05). Re-wetting agent group was similar with the control group in acid etch group (P > 0.05) and lower than the control group in laser etch group in primary teeth (P < 0.05). CONCLUSION Acid etching in permanent teeth; laser etching in primary teeth was found more successful. The use of re-wetting agent did not provide an advance on bond strength of the adhesive in both primary and permanent teeth after acid-etch or laser-etch.