Effect of various irrigation protocols and antioxidant application on bonding performance of two adhesive systems to coronal dentin.

Background: The aim was to evaluate the effect of different irrigation protocols and antioxidants application on the shear bond strength (SBS) of two different adhesive systems to deep coronal dentin at different temperature. Material and Methods: One hundred and twenty human premolar teeth were cut longitudinally in two halves, then the prepared specimens were allocated into four main groups according to the irrigation protocols; Distilled water (control), Sodium hypochlorite (NaOCl) + Ethylenediamine Tetra-acetic Acid (EDTA), and NaOCl + Editronate (HEDP), two subgroups according to irrigation solutions temperature; 4°C and 37°C, two divisions according to grape seed extract (GSE) application (with and without), and two subdivisions according to the applied adhesive systems; OptiBond-All-In-One (OPT) and ScotchBond Universal (SBU). Adhesives were applied in self-etch (SE) mode and resin composite material discs were built. Specimens were kept in distilled water for 24-h at 37°C before SBS testing. Four-way ANOVA and Tukey HSD tests were used for data analysis (α=0.05). Results: 4°C irrigants solution temperature showed the least significant SBS values, distilled water group showed significantly higher SBS values compared to NaOCl + EDTA and NaOCl + HEDP groups respectively. GSE application improved dentin bond strength significantly within each adhesive. Conclusions: Increasing the temperature of the irrigation solutions has significantly enhanced the SBS of coronal dentin. Antioxidants application following different irrigation protocols has improved the SBS. Key words:Irrigation protocols, temperature, bond strength, coronal dentin, antioxidant, adhesive systems.

Evaluation of different decontamination procedures on bond strength to sound and caries affected dentin using "no-wait" universal adhesive.

BACKGROUND: Current study aimed to evaluate the effect of different decontamination procedures on micro-shear bond strength (µSBS) of sound (SoD) and caries-affected dentin (CAD) of two universal adhesives after blood-saliva contamination. METHODS: One hundred and eighty bovine anterior teeth were prepared and allocated into the respective groups according to tested dentin substrates [SoD, CAD], universal adhesives [Clearfil Bond Universal Quick (UBQ), All-Bond-Universal (ABU)], adhesive contamination stage [none, contamination before and after adhesives light-curing], and according to decontamination procedures [no decontamination, water rinsing, adhesive rebond, Ethylenediaminetetraacetic acid (ETDA) and chlorhexidine (CHX) application]. Universal adhesives were applied according to manufacturer instructions in self-etch (SE) bonding mode. Four composite microrods were built for each tooth. Specimens were kept in distilled water for 24 hours at 37°C before testing µSBS. Four-way ANOVA and Tukey HSD tests were used for data analysis. RESULTS: A statistically significant difference between contamination stages of both universal adhesives at different decontamination procedures for SoD and CAD. Highest µSBS was recorded for UBQ control group at SoD, while the least was recorded for light-cured ABU upon water rinsing decontamination procedure of CAD. CONCLUSIONS: Proper cavity isolation is mandatory to avoid possible contamination which can dramatically affect µSBS. CHX is a potent cavity decontaminant that can restore different dentin substrates bond strength. EDTA presents a promising substitute. UBQ adhesive showed better bonding performance than ABU to both dentin substrates. Application of regular cavity decontamination approaches is highly advised in daily practice to avoid possible detrimental effect of accidental cavity contamination.

Comparative evaluation of caries prevalence among group of Egyptian adolescents using DMFS and ICDASII methods: a cross-sectional study.

BACKGROUND: Limited data is available regarding the prevalence of dental caries as a chronic disease among adolescents using different caries assessment indices. The aim of this study was to compare and describe the prevalence of dental caries among group of Egyptian students using two caries assessment indices; DMFS and ICDAS II. METHODS: This descriptive, cross-sectional epidemiological study included 2760 public secondary school students with age range from 15 to 18 years with permanent dentition and good general health. Presence of; retained teeth, congenital or developmental anomalies in the permanent dentition, orthodontic treatments, systematic conditions, smoking and general health problems were considered the exclusion criteria in this study. Participants were selected randomly from 8 public secondary schools in the Great Cairo, Egypt. The examination was achieved by 6 trained and previously calibrated examiners using sets of diagnostic mirrors, compressed air, a WHO probe and cotton rolls. DMFS index and ICDAS II system were used as caries detection methods. In DMFS index; the number of decayed (D), missing (M) and filled (F) surfaces was recorded, while in the ICDAS II index, the assessment of both cavitated and non-cavitated carious, missed and filled teeth with restorations /sealants was recorded. The examiners performed the oral examination using both scoring systems in an alternating manner. The collected data were explored for normality using Kolmogorov-Smirnov and Shapiro-Wilk tests. Chi square test was used to analyze the frequencies. RESULTS: There was a statistical significant difference between the DMFS and ICDAS II methods results regarding the recorded number of caries affected teeth and cavitated teeth surfaces. The prevalence of dental caries among the investigated secondary school students was (69.56%) and (78.29%) for DMFS and ICDAS II, respectively. CONCLUSIONS: The prevalence of dental caries among Egyptian adolescent is high. ICDAS scoring system revealed higher caries prevalence values than DMFS method. ICDAS method is the best choice for the preventive goals, while DMFS is sufficient for clinical purposes.

Effect of Arginine and nano-hydroxyapatite application on the hypersensitivity and color change of bleached enamel: A randomized controlled clinical trial.

Background: To evaluate the effect of 2.5% Arginine and nano-hydroxyapatite (nHA) application on the post-bleaching hypersensitivity (HS) and color change in a randomized controlled trial. Material and Methods: Sixty-four participants were randomly allocated to four groups (n=16) according to the investigated desensitizing agents (UltraEZ gel, experimental 2.5% Arginine, 2.5% nHA pastes and control (no treatment) groups). An in-office chemical bleaching agent (40% hydrogen peroxide) was used for vital bleaching of the anterior teeth. The desensitizing agents were applied to the assigned groups and left for 30 min then rinsed off the teeth. HS was evaluated using Visual Analogue Scale (VAS) from 0-10, immediate (after bleaching), first seven days, then every week for 3-w. Color change was evaluated using VITAPAN classical A1-D4 at baseline (before bleaching), immediate (after bleaching), and after 1,2, 3-w. Results: HS results showed statistically insignificant difference between the tested groups at day-1 and -2. All groups showed no HS (0) at/and after day-3. There was a statistically significant color change between immediate, 1-w and 2-w and baseline results for investigated materials. No statistically significant difference was recorded between the baseline and 3-w for the investigated materials. Both Arginine and nHA groups showed a higher color change compared to UltraEZ group. Conclusions: Arginine and nHA present a potential treatment modality for the post-bleaching HS without jeopardizing the bleaching efficiency. Key words:Arginine, nano-hydroxyapatite, bleached enamel, hypersensitivity, color change, clinical trial.

Effect of açai berry extract application on the bond strength to the bleached enamel using an experimental etch-and-rinse adhesive.

Background: To evaluate the bleached enamel shear bond strength (SBS) after antioxidants application using an experimental adhesive. Material and Methods: Sixty sound human molars had their roots removed then cut into buccal and lingual halves and mounted in acrylic blocks. Enamel bleaching was done using an in-office chemical bleaching agent. Specimens were arbitrarily allocated into 12 groups (n=10) regarding the three experimental levels of the study: two antioxidant agents [10% açai berry extract, 10% sodium ascorbate prepared gels (applied for 15-min) and the control group (no antioxidant application)], two adhesive materials [commercial etch-and-rinse (ER) adhesive and an experimental ER adhesive] and two post-bleaching SBS testing times [24-h and 2-w]. Specimens were restored with a nano-hybrid resin composite restoration then stored in distilled water at 37◦C till SBS testing. Results: Three-way ANOVA showed that the antioxidant agents, adhesive materials and the post-bleaching SBS testing times had a statistically significant effect on the bleached enamel SBS. Açai berry extract groups recorded the highest mean values, while the control groups demonstrated the least values with a statistically significant difference between the antioxidant agents' groups. Commercial ER adhesive recorded statistically significant higher SBS values than the experimental adhesive and the 2-w post-bleaching SBS testing time demonstrated statistically significant higher SBS values than the 24-h groups. Conclusions: Açai berry extract is a powerful antioxidant agent, that has the potential to instantly restore the bleached enamel depleted SBS. The commercial adhesive has successfully restored the depleted SBS of the bleached enamel than the tested experimental adhesive. Key words:Antioxidant application, açai berry extract, etch-and-rinse adhesives, experimental adhesive, shear bond strength.

Effect of resin thickness, and curing time on the micro-hardness of bulk-fill resin composites.

BACKGROUND: Bulk-fill resin composite has been introduced, their manufacturers claimed that they can be applied in bulks of 4mm, without necessitating a prolonged curing time, or a light curing unit with increased irradiance. Thus this study was conducted to evaluate the effect of resin thickness, and curing time on the micro-hardness of two bulk -fill resin composites; Tetric Evo-Ceram [TE], and X-trafil [XF]. MATERIAL AND METHODS: 120 cylindrical specimens were prepared, and divided into 24 groups (n=5/group), representing the two bulk-fill resin composites, three different material thicknesses (2, 3 and 4 mm) and the four curing times used in the study (10, 20, 40, and 60 seconds). The specimens were light-cured from the top surface only. Specimens were stored in light proof containers in complete darkness at 37°C for 24 hours. Micro-hardness test was conducted on both top and bottom surfaces using Vickers micro-hardness tester with 500 g load and a dwell time of 15 seconds. Data were statistically analyzed by Four-way ANOVA of Variance. The significance level was set at P ≤ 0.05. Pearson Correlation used to determine significant correlations between mean micro-hardness (top) and (bottom) surfaces. RESULTS: Four way-ANOVA shows that different tested materials produce a statistically significant effect on mean micro-hardness (VHN) at p≤0.001, while thickness, curing time, and surface revealed statistically non significant effect on mean micro-hardness (VHN) at p≥0.05. [XF] (92.01±3.15 VHN) showed statistically significant higher mean micro-hardness than [TE] (54.13±4.96 VHN). Pearson Correlation revealed that there was a significant direct correlation between micro-hardness (bottom) and mean micro-hardness (top) (mm), r = 0.985, p (2-tailed) ≤0.001. CONCLUSIONS: Within the limitations of this study, the bulk-fill resin composites used in this study can be placed and cured properly in the 4 mm bulk. KEY WORDS: Bulk-fill resin composite, micro-hardness, thickness, curing time.