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Introduction:Failure of orthodontic bonded retainers may affect the orthodontic results and cause relapse.Objectives:To compare in vitro the effect of vertical load on failure of three different bonded lingual retainers:Flat braided wire “Bond A. Braid”, Dead soft wire “RESPOND”, Fiber reinforced composite “Infibra Ribbon”. Bonded with Tetric-N Flowadhesive system.Materials and Methods:Ninetymandibular incisors were used in the study, thirty specimens (N=30) in triads divided into 3 groups (n=10 for each group). Roots of the incisors were covered with elastomeric impression material to mimic periodontal ligaments elasticity and embedded in triads in acrylic resin blocks. They were randomly divided into 3 groups to receive the following retainer wire materials:Group A (Flat braided wire “Bond A. Braid”), Group B (Dead soft wire “RESPOND”), and Group C (Fiber reinforced composite “Infibra Ribbon”). And these retainer wires were bonded to the lingual surfaces using Tetric-N Flowadhesive system.The three groups were subjected to 10,000 thermal cycles between 55▫C & 5▫C using a thermo-cycling machine. Each specimen was subjected to loading forces at the incisal edge of the middle incisor for 125,000 cycles. Then failure forces were measured using a Universal Testing Machine at a cross head speed (1mm/min) applied on the wire of the interproximal segments.Failure sites were determined and the adhesive remnant index (ARI) was observed using a stereomicroscope at (×20) magnification.Results:Mean debonding forces were 46.27 ±12.28, 36.03 ± 6.09, 30.09 ± 15.73 N for Groups A,B and C respectively, presenting significant difference between the groups (p < 0.05). The highest value for the mean force was found for the Bond-A-Braid (group A) and the lowest value for the mean force was found for the FRC (group C). There was no statistically significant difference in displacement among test groups. There was no fracture occurred of any wire. There was no significant difference between the distribution of the ARI score between the three groups (p=0.322).The ARI scores were observed under the optical stereomicroscope showing multiple failures at the composite-wire interface and the tooth-composite interface.Conclusions: There was a significant difference between “Bond A. Braid” wire and “FRC” where “Bond A. Braid” had the highest debonding forces and the “FRC” had the lowest debonding forces. There was no significant difference in displacement of the retainers between the three groups. There was no significant difference between the ARI of the lingual retainer systems and types of failure as well.

Introduction: Propolis is a natural product collected by bees. Contemporary dentistry has recently focused on it, due to its antimicrobial properties. Objectives: To evaluate and compare the microleakage and microhardness of GIC containing EEP at 2 different concentrations to the conventional GIC. Materials and Methods: Two tests were assessed 1. Microleakage test :where 24 exfoliated primary teeth were divided randomly into three groups according to the restorative material used after standardized class V cavity preparation: (Group1: Conventional GIC, Group2: GIC containing 25% EEP, and Group 3: GIC containing 50% EEP), teeth were immersed in 2% methylene blue solution for 24 hours, sectioned and examined under stereomicroscope. 2. Microhardness test: 8 specimens from each group (GIC, GIC 25% EEP, and GIC 50% EEP) were prepared using a mold of six mm in diameter and two mm in thickness. The hardness of the specimens was measured using Vickers Micro-hardness Tester. Results: There was no statistically significant difference in the microleakage scores between the three groups (p=0.34).The Microhardness values of the present study showed that GIC with 25% EEP showed significantly higher values than both the conventional GIC and GIC with 50% EEP (p 0.05) Conclusion: The addition of EEP to GIC in either (25%, 50%) did not affect the microleakage of GIC. Addition of 25% EEP increased the microhardness of the GIC while the addition of 50% EEP did not affect the microhardness of GIC

INTRODUCTION: Different irrigations solutions may cause alteration in the physicochemical properties of dentin structure thereby affecting the microhardness of root canal dentin. OBJECTIVES: to evaluate the effect of different irrigation protocols on microhardness of human root canal dentin. MATERIALS AND METHODS: Forty extracted single rooted lower premolars were used. All teeth were instrumented using manual stainless steel files and irrigated by 2ml distilled water between each file, then were sectioned by longitudinal splitting of each tooth. The root halves were randomly assigned into 4 parallel groups (n=10) and immersed for 5 minutes with one of the following irrigants: Group I: 10 ml of 2.5% Sodium Hypochlorite (NaOCL), Group II: 10 ml of 17% ethylene diamine tetra-acetic acid (EDTA) followed by 10 ml of 2.5% NaOCL, Group III: 10 ml of 2.5% NaOCL followed by 10 ml of 2% chlorhexidine digluconate (CHX), Group IV: 10 ml of 2.5% NaOCL followed by 10 ml distilled water then were followed by 10ml of 2% CHX. Ten root halves from each group were prepared to measure dentin microhardness at baseline measurement and after treatment to determine the change in microhardness, using Vickers tester. RESULTS: Data were analysed using t-test, ANOVA test and Post Hoc test.Group II showed the highest percentage decrease in microhardness values, followed by group III, then group IV and the lowest was group I. All groups showed a significant difference between each other (P < 0.05), except group III and IV. The coronal third showed the highest percentage decrease with significant difference between apical and middle thirds (P < 0.05), in which there was no significant difference between them. CONCLUSIONS: CHX is the best final irrigant if there is excellent intermediate flush for prevention of its precipitation with NaOCL.The coronal third needs conservative approach as it is the most affected third.

INTRODUCTION: Different irrigations may cause alteration in the composition of dentin, thereby affecting the adhesion of materials to dentin surfaces. OBJECTIVES: evaluate the effect of different irrigating protocols used as final rinse on the bond strength of the ActiV gutta percha. MATERIALS AND METHODS: Forty extracted single rooted lower premolars were used. Teeth were decoronated to standardize the root length to 15mm. The canals were instrumented using OneShape rotary system. Teeth were irrigated with 2.5% sodium hypochlorite then divided into four parallel groups according to the final rinse (n=10). GroupI: 10ml 17% Ethylene diaminetetraacetic acid, followed by 10ml of 2.5% NaOCL; GroupII: 10ml of 1.3%mixture of a tetracycline isomer, an acid and detergent (MTAD); GroupIII: 10ml of 2% chlorhexidine gluconate; GroupIV: 10ml 2.5% NaOCL(control). All the root canals were filled using ActiV GP. Slicing was done at the coronal and middle thirds for push-out test to measure bond strength. Then failure mode was evaluated under stereomicroscope. Data were analysed using t-test and one-way ANOVA test. RESULTS: Group III yielded significantly the highest mean push-out bond strength (2.91± 0.79 MPa), followed by group II (2.39± 0.89 MPa), then group IV (1.80± 0.61MPa) and finally group I (1.61± 0.52 MPa). The bond strength values of the middle sections were significantly higher than that of the coronal sections. The failure mode was predominantly cohesive in groups II and III and adhesive in groups I and IV. CONCLUSIONS: CHX and MTAD increased the bond strength of ActiV GP, while EDTA decreased the bond strength. The push out bond strength values were affected by the location of root segment. There was correlation between the push out bond strength values and the failure mode.

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.

Aim: To evaluate the microleakage of the glass carbomer cement with and without protective surface coat in primary molars and to compare it to conventional glass ionomer cement. Materials and Methods: Forty sound primary molars were included in the study. They were divided into two groups (n=20) according to the restorative material tested. Group A (experimental group): Teeth were restored using glass carbomer cement, and group B (control group): Teeth were restored using conventional glass ionomer cement. Then each group was further subdivided into two sub-groups according to the presence of surface coat. After teeth restoration, they were immersed in methylene blue solution for 24 hours then they were sectioned longitudinally into two equal halves and tested for microleakage. Results: There was a statistically significant difference between the microleakage scores of glass carbomer cement with surface coat (sub-group A1) and without protective surface coat (sub-group A2) in favor of sub-group A1. However, there was no statistically significant difference between the microleakage scores of conventional glass ionomer cement with surface coat (sub-group B1) and without protective surface coat (sub-group B2). By comparing the 4 sub-groups, sub-group A1 showed the lowest microleakage score, while sub-group A2 showed the highest score with statistically significant difference. Conclusion: Surface coat when added to the glass carbomer cement yields less microleakage than the unsealed glass carbomer and conventional GIC.