Abstract: Aims: The purpose of this invitro study was to evaluate the effects of a flowable composite associated with an adhesive, either light cured separately or co-cured on the microleakage of class V composite restorations. Material and methods: Sixty extracted human premolars were prepared with standar-dized box shaped class V cavities of 3.0mm (Mesial distal), 2.mm (occlusal gingival) and 2.0mm depth with margins located on enamel and dentin on the buccal surfaces. The cavities were randomly as-signed in the three groups (n=20): Group 1- single bond + tetric ceram (hybrid composite) as control group. Group 2- single bond + tetric flow (flowable composite) light cured simultaneously + tetric ceram. Group 3- single bond + tetric flow light cured separately + tetric ceram. After sto-rage period of one week in water, All specimens were thermo-cycled for 300 times with 15 seconds dwell time, and immersed in 2% methylene blue, sectioned and evaluated for microleakage using 0-3 scale. Data were subjected to Fisher Freeman Halton test at p

Abstract: AIMS of this study are to investigate the bond strength and mode of failure of different tooth materials with and without surface treatment to acrylic resin denture base cured by microwave in relation to wa-ter bath techniques. MATERIALS AND METHODS: One hundred sixty samples of five different brands of acrylic teeth were divided into four groups (untreated and treated groups each of these were cured by water bath or microwave techniques). The bond strength between acrylic tooth and denture base resin was measured in shear mode by using unconfined compression machine. The shear bond strength (SBS) in MPa was calculated, debonded surfaces were examined using visual examination and reflecting light microscope . Analysis of variance (ANOVA) and Duncan’s multiple range tests were used for statistical analysis. RESULTS: there was a significant difference in bond strength of acrylic denture base to different tooth materials (P < 0.001). CONCLUSIONS: SBS of acrylic teeth treated by monomer surface treatment for 180 seconds to microwave cured resin was significantly higher than that of water – bath cured resin, and cross – linked acrylic teeth showed lowest SBS compared to other type of acrylic teeth.Key words: Microwave, Bond strength, Cross – linked acrylic teeth.

Abstract: Aims: To determine the suitability of new modified Iraqi plaster and modified Plaster of Paris as a cast in microwave curing of acrylic denture base material, and microwave and open air drying methods on the surface roughness and dimensional accuracy of the cast. Materials and methods: Two types of gypsum products were used in this study {(Iraqi plaster, Plaster of Paris) with the combined additives (Gum Arabic 0.5%, calcium oxide 0.75%, and ferric oxide 0.2%), and Type III stone Plaster/Stone 3:1} that incorporated within the two gypsum products. The effects of drying method and combined additives on the surface roughness and dimensional accuracy of the experimental gypsum products, and acrylic denture base pro-duced from the modified gypsum casts have been evaluated. Mean, standard deviation, variance (ANOVA), and Duncan's multiple range tests were used to analyze the measurements. Results: ANOVA test showed that there was a significant difference in the surface roughness and dimensional accuracy between Iraqi plaster and plaster of Paris with or without additives dried in open air and microwave techniques. Conclu-sion: There was slight dimensional change in the gypsum cast with additives of clinical importance to compensate the polymer shrinkage of the acrylic denture base after cooling. There was no significant dif-ference in the average roughness of acrylic resin cured by microwave oven as a curing method. Keywords: acrylic, roughness, dimensional accuracy.

Abstract: ِAims: The study aims to record the value of the removal force of heat cure (control group), cold cure and visible light cure with two design (close fit and spaced custom tray) and to compare between these values. Materials and Methods: Five custom trays was constructed for each materials used in this study which is heat cure(control group) , cold cure and visible light cure resin with two design close fit and spaced custom tray and the value of the removal force was calculated by using instron testing ma-chine. Results: The visible light cure custom tray produced less value of removal force when compared with the cold cure and heat cure custom trays and the heat cure custom tray produced a less value of removal force when compared with the cold cure custom trays. The spaced design produced less value in the removal force than the close fit design for each material used in this study. Conclusions: The visible light spaced custom trays produced less value of removal force than the cold and heat cure cus-tom trays. Key word: Visible light cure, Removal force, Custom tray, Bone resorption.

Abstract: Aim: To compare the effectiveness of four different disinfectant solutions in rapid decontamination of gutta percha cones. Materials and Methods: In this experimental study, 320 gutta percha cones were placed in bacterial suspensions of Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Can-dida albicans for 30 minutes, and then immersed in disinfectant solutions (6% hydrogen peroxide, 2% chlorhexidine, 1% sodium hypochlorite, and 70% ethyl alcohol) for 1, 5, 10, and 15 minutes. After that, the cones were aseptically transferred to the test tubes containing 4 ml brain heart infusion broth, and then cultured on selected agar media and number of colonies was estimated after 24 hours incubation at 37 oC. Results: Hydrogen peroxide was effective in 1 minute, while chlorhexidine and sodium hypoch-lorite after 10 minutes, and ethyl alcohol in 5 minutes for decontamination of gutta percha cones. Con-clusion: Hydrogen peroxide was the most effective agents in decontamination of gutta perch cones

Abstract: Aims: To evaluate the effect of different xylitol preparations (chewing gum and strips ) on gingival, plaque indices and salivary fluid composition (calcium, total protein, and uric acid ). Materials and Methods: Twenty nine healthy dental students aged 20-24 years, were divided randomly into two groups, the first group used chewing gum sweetened with xylitol and the second took xylitol strips for 21 days. The plaque and gingival indices were examined at the baseline and at the end of treatment, together saliva samples were collected in the same periods for the measurement of salivary flow and salivary concentration of calcium, total protein and uric acid. Results: The results confirmed on going changeability of the oral cavity environment after treatment with xylitol preparations in both groups. There were reduction in plaque and gingival indices in both groups, but it was significantly reduced in strip treated group (P< 0.0001 and P<0.01 respectively). Salivary concentration of total protein was significantly decreased in strip group ( P <0.05 ) and in gum group ( P<0.0001 ) against baseline Val-ues. Xylitol strips have pronounced effect on the gingival index (P<0.0001) when compared with xyli-tol gum . Conclusions: The regular use of different xylitol preparations has its protective effects on the oral health hygiene. Key Words: xylitol, Salivary flow, Gingival index, Plaque index, Oral health .

Abstract: Aim: To evaluate the quality of the impressions recorded for fixed and removable partial dentures and for completely edentulous patients by describing the frequency of clinically detectable errors. Mate-rials and Methods: A total of 250 impressions were evaluated immediately after they were recorded by two examiners. Three different impression materials were employed. Data relating to errors and faults including those related to tray construction, or related to impression materials used and those related to the operator were evaluated and analyzed. Results: Of 100 irreversible hydrocolloid impres-sions for partially edentulous arches, 90% had one or more detectable errors; while for condensation type of silicon 50% had one or more detectable errors. For complete denture impressions, silicon rub-ber base showed the least errors than zinc oxide eugenol paste impression and irreversible hydrocolloid that showed the highest errors. For fixed partial denture, impressions were recorded by silicon rubber base; the occurrence of faults were as follow: Voids in finish line 20%, detachment 6.6%, tearing 6.6%, premature removal 10% and pressure area 3.3%. Conclusion: Irreversible hydrocolloid impression material showed the higher detectable errors. Key Words: Impression materials, faults of impressions, irreversible hydrocolloid, silicon impression.

Abstract: Aims: To investigate the antimicrobial effect of different concentrations of ethanolic and aqueous extracts of Sage and Rue (0.5%, 0.05%, 0.005%) on bacterial samples. They were iso-lated from root canal system in vitro, and the results were compared with that of chlorhexidine glu-conate (0.2%) as a positive control and normal saline as a negative control. Materials and Methods: Eighteen hours cultured bacterial samples of the root canal were used. To each 4ml of Brain Heart Infusion Broth (BHI), 0.1 ml of both bacterial sample and the examined solution Sage, Rue and chlorhexidine were added. Cultures were incubated at 37°C for 48 hours. The absorbance val-ues of the cultures were determined by the turbidity method using spectrophotometer at (550 nm). Re-sults: The results showed that both ethanolic and aqueous extracts of Sage and Rue have anti-bacterial effects in all concentrations with a significant variance compared with chlorhexidine against root canal microorganisms, while normal saline failed to show any antimicrobial activity. The results also showed that the ethanolic extracts of both plants have a higher antibacterial activity than the aqueous extracts. Conclusions: Rue and Sage demonstrated antibacterial effects on the root canal microorganisms (both aerobic and anaerobic) when compared with chlorhexidine.

Abstract: Aims: This study perfoemed were to evaluate the effectiveness of ethanolic extract of leaves (EEL) at different concentrations and latex (LX) of Ficus carica against Enterococcus faecalis, and to evaluate the most effective concentration of EEL and LX against Enterococcus faecalis in dentinal tubules when used as intracanal medicament. Materials and Methods:The different concentrations of EEL (5%,2.5%,1.25%,0.6%,0.3%,0.1%) and LX against Enterococcus faecalis was evaluated by broth mi-crodilution method using spectrophotometer. One hundred and twenty freshly extracted single canal humen teeth were chosen. They were section at cementoenamal junction, instrumented, sectioned apic-al one third, and then sterilized. They are then contaminated with Enterococcus faecalis solution and incubated. These samples divided into three groups randomly. Root canals filled with 5% EEL, LX, and formocrsol and maintained for one day for group one, for three days for group two, and seven days for group three. The medicaments removed from the canal and dentin chips was obtained from the can-al and weight 10 mg that will be diluted in brain heart infusion broth, and cultured on blood agar then the number of colonies recovery were estimated. Results: this study obtained that 5% EEL had best effect than other concentrations but its effect less than LX but significantly not different. Result also obtained that 5% EEL and LX capable after seven day to eliminate the Enterococcus faecalis from In-fected dentinal tubule, while formocresol can not. Conclusions: The EEL at 5% and LX had sufficient antibacterial effect against Enterococcus faecalis in the infected dentinal tubules when they are used as intracanal medicaments.

Abstract: Aims: To measure the shear bond strength of three dental adhesive systems, self-etching priming sys-tem (Clearfil SE Bond), total-etch adhesive system (Prime &Bond NT) and all-in one adhesive (Etch & Prime 3.0 (E&P)), also to compare the effects of aging restorations with different time intervals (1-day, 1-week and 1-month) on dentin bond strength at room temperature. Materials and Methods: One hundred and eight human molars were embedded in self-cured acrylic resin, abraded on a water-cooled and polished with 80-400 grit sand papers to obtain standard dentin surfaces. The specimens were ran-domly assigned into three groups: (36 teeth) for Clearfil SE Bond, (36) for Prime&Bond NT and (36) for Etch & Prime 3.0 (E&P) adhesive systems were used at room temperature. These adhesive systems were applied to dentin surface according to the manufacturers’ instructions. A composite resin (Tetric composite resin (USA)) cone was bonded to dentin surface. These groups were sub-divided into 3 sub-groups (n=12), as in the following: (36) for Clearfil SE Bond; (12) were stored at 1-day, (12) at 1-week and (12) at 1-month time intervals, with the same criteria for Prime&Bond NT and Etch & Prime 3.0 (E&P). The specimens were stored in distilled water at room temperature and submitted to Universal Testing Machine at a crosshead speed of 0.5 mm/min. Means in MPa were analyzed statistically by Duncan′s Multiple Range Test at significant level of (p>0.05). Results: The results showed higher means of shear bond strength for Clearfil SE Bond and Prime &Bond NT were at (1-week) interval. While the higher bond strength for Etch & Prime 3.0 (E&P) were at (1-day) interval. The lower means of bond strength for Clearfil SE Bond were at (1-day). While for Prime &Bond NT and Etch & Prime 3.0 (E&P) were at (1-month) time interval. Etch & Prime 3.0 presented lower means of bond strength than Prime & Bond NT at (p<0.05). The results of this study revealed that Clearfil SE Bond showed the highest bond strength than other adhesives used in the study, which was significantly differ from Prime&Bond NT and Etch & Prime 3.0 (E&P) adhesive systems for the three time intervals used. Conclusions: In conclusion, a statistical difference between adhesive systems used in bond strength to dentin were observed when adhesives used with different aging intervals for (1-day, 1-week and 1-month). Self-etch bonding systems was showed a higher strength than total-etch adhesive systems. Etch & Prime 3.0 showed nearly equal bonding strength with the total-etch adhesives. The bonding strength of adhesive system was influenced by the type of the bonding system used with different time inter-vals.

Abstract: Aim : To describe the incidence of Burkitt lymphoma (BL) in the North Iraq with special regard to the incidence of BL of the jaw bone. Materials and Methods:The records of patients with lym-phoma between the years 1981-1990 and 1995 -1999 in Hazim Al-Hafid Hospital in Mosul City were reviewed and they are analyzed with special regard to the BL including age,sex and the site distribu-tion of the lesions. Results: One thousand and two records of the patients with lymphoma were re-viewed .Seventy cases of them were BL consisting 7% of all lymphomas. Four cases (5.7%) of the BL were present as jaw bone lesion. The age range for patients with BL of the jaw bone was 4 – 12 years with mean of age 7.5 years . All patients of BL of the jaw bones were male .No lesion of the jaw bone showed metastasis to the brain where prognosis become worse. Conclusions: BL in our country can be occurred in the intestine and even in the jaw bone so it must be included in our differential diagnosis of the jaw bone lesions.

Abstract: Aims: The aim of this study was to determine the mesiodistal tooth width of the permanent dentition, interarch tooth size ratios and to compare these variables between genders and among different maloc-clusion and normal occlusion groups for Iraqi adolescent in Mosul City. Materials and Methods: 141 orthodontic models of school students aged 13 – 16 years of different occlusal relationships (class I normal occlusion, class II (division 1 and 2) and class III malocclusion). Mesiodistal width of teeth were measured by using dental vernier. The mean and standard deviation were calculated. Student's t –test, analysis of variance, Duncan's multiple analysis range test and Pearson's correlation coefficient were used for the statistical analysis. Results: Although the males had a larger mesiodistal width of most of the teeth than those in the females, but some of these measurements were not significantly different par-ticularly in class I normal occlusion, while the most significant gender differences were found in class II division 1. Class I normal occlusion showed a tendency toward small teeth than the malocclusion groups particularly in males group, while the class III malocclusion showed a tendency toward larger teeth than the other occlusal categories specially in females group. The class I normal occlusion had a higher ante-rior tooth ratio than that in class III malocclusion and a higher overall tooth ratio than that in the maloc-clusion groups in females. While in males the overall tooth ratio was smaller in class II division 1 than that in class I normal occlusion. No gender difference for the tooth ratios in all occlusal categories ex-cept in class II division 2 malocclusion. Conclusions: It was concluded that interarch tooth size rela-tionships are population specific and there is a gender specific for mesiodistal width of some teeth par-ticularly in class II division 1, and these ratios may be one of the important factors in the cause of ma-locclusion, thus, this study proved the fact that Bolton's analysis should be taken into consideration dur-ing orthodontic diagnosis and therapy.

Abstract: Aims: To determine some physical and biochemical characteristic of the saliva in insulin dependant diabetes mellitus (IDDM) patients compared to control group and to correlate the salivary variables to any alteration in the oral health status which is evaluated by recording the plaque index, gingival index, and calculus index. Materials and Methods : Salivary samples were collected from 20 IDDM patients and 15 healthy male with age range (20-28) using simple spitting method. Salivary flow rate, pH value, total proteins, calcium, sodium, and potassium concentration were determined for each sample. Clini-cal examination was performed for both, patients and control groups to determine the plaque index (PI), gingival index (GI), and calculus index (CI). Results: The salivary samples of IDDM patients showed significantly lower salivary flow rate, pH value, and calcium concentration when compared with control group, while total proteins and potassium concentration were significantly higher. The PI, GI, and CI were significantly higher in IDDM Patients. Conclusions: Our results suggested that IDDM is one of the pathological conditions that alter the properties of sali-vary secretion. The oral health status in IDDM in addition to its relation to the systemic condition; it is also related to the salivary properties

Abstract: Aims: To compare the mean shear bonding force and mode of bond failure of metallic brackets bonded and rebounded (using new and pre-used brackets) to sandblasted and acid-etched enamel is described. Materials and methods: The buccal surfaces of 40 extracted human premolars were sandblasted for 5 seconds with 50 μ alumina at 4mm distance and the buccal surfaces of a further 40 human premolars were acid etched with 37% phosphoric acid for 20 seconds. Following storage for 24 hours at 37°C in distilled water, then each group was divided into four subgroups of ten teeth, shear bonding force and the bond failure were measured for bonded and rebounded new and pre-used brackets using a Univer-sal Testing Machine with a cross-head speed of 10 mm/minute. Results: The mean shear debonding force was significantly lower for brackets bonded to sandblasted enamel compared to acid etched ena-mel (P < 0.000), the same thing for the rebounded brackets, with the lowest shear bonding forces for brackets bonded to sandblasted enamel in the first and second step while the shear bond strength was higher for brackets bonded to acid etched enamel what ever the first treatment of enamel weither con-ventional acid etching or microetching. Statistical analysis showed that at a given stress the probability of failure was significantly greater for brackets bonded to sandblasted enamel. This is in the first step, the same thing in the second step was greater probability of bond failure for enamel treated in the first and second step with Microetcing and still greater in teeth treated with Microetching opposite to that is for teeth treated in second step with acid etching and the significantly lower probability of bond failure for brackets bonded to acid etched enamel in first and second step. Brackets bonded to acid etched enamel showed a mixed mode of bond failure (adhesive and cohesive failure) , whereas following sandblasting, failure was adhesive at the enamel/composite interface (p < 0.000). Conclusions: What-ever the first step of treatment, higher shear bond in the second step could be obtained using acid etch-ing with new and old brackets, but in cases treated with acid etching in first step and microetching in second step a suitable shear bond strength could be obtained insist with new brackets.

Abstract: Aims: The purpose of this study was to evaluate the reaction of the subcutaneous connective tissue to a new sealer composed of ethanolic extract of Propolis (EEP) and zinc oxide powder. Materials and Methods: Twenty five adult rats (Rattus novergicus, Albinos wistar) weighting between 200 and 250 grams, provided by central animal house of Mosul University of the Veterinary College were used. Materials were autoclaved polyethylene tubes, 10mm long with a single lumen and an inner diameter of 1 mm, ensuring that air was not entrapped. The procedure was preformed in the subcutaneous tissue of the rat in the dorsum of the animal following the sagittal line between the frontal legs, was submitted to trichotomy for exposure of the skin, followed by a sepsis with a gauze soaked with 70% alcohol. Results: No rats died during the experimental study. The surviving skin appeared normal in this texture and bled when cut, compared to negative control. The connective tissue responded along the lateral wall outside the polyethylene tubes of all specimens also served as a negative control. A moderate in-flammatory reaction was observed in the second day when new sealer was used. The tissue reaction showed a focal neutrophilic inflammatory infilterates. On the 7th day a mild to absent inflammatory reaction were observed. The histological features on the 14th, 30th and 60th days showed similar fea-tures. Conclusions: The results obtained in the present study allowed the conclusion that the new root canal sealer composed of zinc –oxide (powder) and EEP (liquid) presented good biocompatibility.

Abstract: Aims: In an effort to improve the shear bond strength of resin modified glass ionomer cement on orthodontic brackets, various enamel conditioning have been evaluated for use with this cement. Materials and methods: A total of 100 freshly extracted human premolars were subjected to two steps of treatment. The first step of treatment involve dividing the teeth into 5 groups each of 20 teeth: (I) treated with 20 second acid etching with 37% phosphoric acid; (II), treated with micro–etching using 50 μ aluminum oxide; (III), treated with air polisher using 45 μ sodium bicarbonate; (IV), treated with coarse finishing disk for 10 second; (V), left the enamel clean without treatment. In the second step each group then subdivided into two subgroups, ten teeth subjected to wetting with tab water and ten left dry. Following, storage for 24 hours at 37°C in distilled water, shear debonding force was measured using a Universal Testing Machine with a cross–head speed of 10 mm/minute. Results: The result indicated that the highest shear bond strength was for acid etched enamel under wet condition with lowest mean for normal dry enamel. the Mann–Whitney analysis estimated a significant difference between wet and dry condition in general with high probability of bond failure for the dry than that of wet conditions. Conclusions: The suitable enamel conditions regarding the shear bond with the mode of bond failure had been shown to be the wet and dry situation of group III and wet situation of group IV. But, it could be concluded that the most suitable enamel condition may be that treated with a coarse finishing disk under wet condition.

Abstract: Aims: The aim of this study was to evaluate the effectiveness of microwave irradiation sterilization on Molloplast –B soft denture liner. Materials and Methods: Sixty specimens of Molloplast –B soft den-ture liner were fabricated in a standardize procedure and autoclaved. The total 60 specimens were di-vided into 4 groups. Each group has 15 specimens inculated with Brain Heart Infusion Broth (BHI) media containing one of the tested microorganisms (Staphylococcus aureus, Bacillus subtilis, Pseudo-monas aeroginosa and Candida albicans). Then the 15 specimens in each group was further divided into 3 subgroups: group C (positive control); 5 none irradiated specimens, group D (dry microwave treat-ment); 5 specimens placed in a dry beaker and microwave irradiated at 540W for 6 minutes, group W (wet microwave treatment; 5 specimens immersed in distalled water and irradiated in the same manner as group D. After incubation of all specimens for 24 hours at 37°C, the specimens were got vortex and then the replicated specimens (100μL) of suspensions were plated on 4 selective media appropriate for each organism. All plates were incubated at 37°C for 48 hours. After incubation, colonies were counted. Further 7 days incubation for microwaved specimens was done to verify the effectiveness of dry and wet microwave sterilization. Results: Significant reduction in cfu/ml of all microorganisms was observed at 48 hours. No growth of C. albicans was recorded at 48 hours and after 7 days incuba-tion. Conclusions: Microwave irradiation at 540W for 6 min in dry and wet conditions was proved to be effective in the disinfection of soft lining material specimens contaminated with Staph. aureus, Ps. aeruginosa and B. subtilis. Wet treatment was more effective than dry one. Dry and wet microwave treatment sterilized specimens contaminated with C. albicans.

Abstract: Aims: To satisfy the newly reverse modified intra-oral periapical projection, in order to reduce the pa-tient discomfort and eliminate gagging reflex during periapical radiography of the lower posterior teeth. Materials and methods: Twenty voluntaries patients have been used in this research aged between 20-25 years, each patient subjected for two intra-oral periapical radiographic examinations for lower posterior teeth (premolars and molars). The first radiographic exami-nation has been made with ordinary principles of intra-oral periapical radiographic projec-tion, while the second radiograph has been made with reverse modified principles of intra-oral periapical radiographic projection. Five independent examiners (two oral radiographer, oral surgeon, oral diagnosis and oral medicine), rated the two radiographic images obtained from both radiographic examination methods. Image quality was assessed by rating the visi-bility of five anatomical landmarks: tooth structures identification (enamel, dentin and root can-al system), bone trabiculation, mental foramen borders, inferior dental canal borders and lamina du-ra. Results: The data collected from the evaluation of the radiographic images obtained from both radiographic projections were analyzed by paired samples chi-square test, which shown no significant difference (P>0.05) in image quality obtained from both techniques for five selected structures. The bone trabeculae and the lamina dura given higher rating of total score with ordinary technique (54, 49 points respectively) when compared with reverse radi-ographic technique (47, 41 points respectively). The highest percentage of unrecognized shadow of mental foramen and the inferior dental canal with use of ordinary radiographic technique (40%, 30% respectively), while the other examined anatomic structures (tooth structure, bone trabeculae and lamina dura) can be identified clearly with both radiographic techniques. Higher percentage of gag reflex and pain discomfort was observed with ordinary technique projection (45%, 40% respectively) in comparison with reverse technique projec-tion (0%, 5% respectively). Conclusion: the reverse intra-oral periapical radiographic technique can be used accurately in the radiographic projection of the mandibular posterior teeth; with minimal pain discomforted and with eliminated gagging reflex initiation.

Abstract: Aims: To find out the effect of topical Nigella Sativa oil on healing of chemically induced oral ulcer. Materials and Methods: Twelve rabbits were used and divided into control and treated groups, the ulcers were induced by injection of 0.3 ml 1%formalin in rabbit cheek mucosa and were treated by daily application of black cumin (N.S) twice on the ulcer site for 3days then the animals were sacri-ficed 5days later. Results: Nigella Sativa (N.S) showed marked anti inflammatory activity on a chemi-cally induced oral ulcer in experimental animals ,histological examination of biopsies from ulcers after three days of treatment revealed difference in the rate of epithelization and healing process of ulcers between the two groups, N.S treatment showed significant enhancement of healing of the ulcers. Con-clusions: Nigella Sativa oil has an obvious effect on the rate of healing process of oral ulcer.

Abstract: Aims: To determine the effectiveness of different disinfection methods on extracted human teeth using five types of bacteria Proteus species, Escherichia coli, Kelebsiella species, Staphylococcus aureus, Streptococcus mutans. Materials and Methods: In this study extracted non-carious teeth were divided into five groups according to the type of bacteria that were inoculated inside the pulp chambers. Each group of the teeth were subdivided into six groups; group A: teeth were immersed in 2.5% NaOCl for 1week, group B: teeth were immersed in 1% NaOCl for 1week. Group C: teeth were autoclaved at 121C for at 15 Ibs psi for 15 minutes, group D: teeth disinfected using microwave for 3 minutes, group E: teeth disinfected using microwave for 6 minutes, group F: control group in which the teeth im-mersed in normal saline for seven days at room temperature. Each tooth aseptically placed in individual test tube with growth media. Simples were examined after 24h. Results: showed that autoclave, mi-crowave (when used at sex and three minutes), sodium hypochlorite at 2.5% prevented the growth completely in all types of the bacteria that were used to infect the teeth involved in this study.

Abstract: AIMS: To determine the period that a new generation of silicone-based, chairside, permanent soft liner resist absorption and solubility and determine the effect of coating material. MATERIALS AND METHODS: Specimens of (Mucopren soft) soft liner were prepared, stored in water, and tested after 1 , 2 , 3 , and 8 months. Half of the specimens were coated with coating material supplied by the manufacturer and the other half remained uncoated. Silica gel was used for drying and sensitive electronic balance was used for weighing specimens. Universal formulas were used for calculating water absorption and solubility. T-test and ANOVA followed by Duncan multiple range test were used to determine the significant difference at P<0.05 level. RESULTS: There was no statistically significant difference between coated and non–coated soft liners in relation to water absorption and solubility. There was no statistically significant difference in water absorption and solubility when comparing it among the periods of testing from the first month to the eighth month. Coating the soft liner decreases the percentage absorption and solubility of the silicone soft liner but this effect is statistically not significant. CONCLUSIONS: Mucopren soft–lining material has proved excellent resistance to solubility for a long period (8 months). Water absorption is limited and is clinically accepted. Coating (Mu-open soft) soft liner with coating material slightly improves the resistance to water absorption and solubility.

Abstract: Aims : The aims of this study were to determine the effect of thickness and additives (Nigella Stavia oil and Thymol oil) on water sorption and solubility of heat cured acrylic resin denture base. Materials and Methods: Two types of heat cured acrylic resin Quayle dental resin and Major base2 were used. Two additive materials (0.5%) have been added to major base 2 which are(Nigella Stavia oil and Thy-mol oil) . Water sorption and solubility of specimens were measured by mean of mass change in ma-terial after water saturation and dehydration. The specimens were prepared in three thicknesses (1mm, 2mm and 3mm). The effect of thickness on water sorption and solubility also has been measured. The data were analyzed using analysis of variance and Duncan's multiple range tests. Results: Increase thickness causes decrease in water sorption and solubility; Q.D has more water sorption and solubility than major acrylic resin. The two additives caused an increase in the water sorption and solubility of major acrylic resin denture base. Conclusions: The thickness and type of manufacturing materials add-ed into acrylic resin played an important role in determining its water sorption and solubility.

Abstract: Aims: This in vitro study was conducted to investigate the effect of various bur types, bonding agents, and resin composite restorative materials on the microleakage at occlusal and gingival tooth/composite interfaces. Materials and methods: One hundred and sixty non carious, extracted human premolars were mounted in acrylic resin, the teeth were randomly divided into four groups (n=40) according to the bur types (diamond round bur, diamond fissure bur, carbide round bur, and carbide fissure bur). A standardize class V (3×2×2) mm dimensions cavity was prepared on the facial surface of each tooth (each group with corresponding bur type), then each group was divided into two subgroups (n=20) ac-cording to the type of adhesive systems used (P&B NT,& I-Bond), after that each subgroup farther divided in to two subgroups (n=10) according to the type of composite restorative materials (Arabesk & Tg) the final number of groups were (16) of (10) teeth in each. After the specimens were finished they stored for one month in 37ºc distilled water, thermo cycled for 500 cycles between (5ºc & 55ºc) and immersed in 0.5% methylene blue solution for 24h., and then sectioned longitudinally. For both occlusal and gingival margins, dye penetration at the tooth/composite interfaces were scored from 0-3 under stereomicroscope at a magnification x10, data were analyzed using unpaired T-test, ANOVA, and Duncan’s multiple rang test at 5% significant level. Results: T-test represent that there was less microleakage at occlusal margins than the gingival margins. ANOVA and Duncan’s multiple rang tests show that the less leakage was occurred with the use of carbide fissure bur at both occlusal and gingiv-al margins while the diamond round bur show the highest leakage at both margins. P&B NT show less leakage than I-Bond at the occlusal margin but there was no significant difference between P&B NT & I-Bond at the gingival margins also there was no significant difference between the ( Arabesk & Tg ) restorations at both occlusal and gingival margins. Conclusions: Within the limitations of this study results show that there was less microleakage at the occlusal margin than that at the gingival margins, and the use of carbide fissure bur to prepare the cavities for receiving resin composite materials show the least microleakage than other type of burs, and although phosphoric acid has been intensely used to etch the dental substrates (enamel and dentin) for providing a good bonding, self-etching adhesives can be considered an alternative methods to provided a good bonding for restorative procedures

Abstract: Aims: To determine the effect of an antioxidant agent on the tensile bond strength values of metal brackets bonded with to human enamel after bleaching. Materials and Methods: Thirty two sound human maxillary and mandibular premolars extracted for orthodontic reasons were collected. All teeth had undamaged buccal enamel, no caries and no pre-treatment with any chemicals. They were then stored in a solution of 0.1 % thymol before the experiment. Results: In the present study, we found that , tensile bond strength in group of direct bonding after bleaching was lower than other groups when compared with control group and the difference was significant at level p< 0.05 . The present investigation confirmed that waiting for a period of 7 days after bleaching is sufficient to obtain ade-quate tensile bond strength for clinical conditions. There was significant difference in tensile bond strength when the brackets that underwent direct bonding and ethanol with control group. No signifi-cant difference in tensile bond strength was observed when compared with the bracket immersed in a distilled water & with control bracket. Conclusions: In the present study we found that , tensile bond strength in group of direct bonding after bleaching were the lowest than other groups and when com-pared with the control group, the difference is significant. There was a significant difference in tensile bond strength when comparing the group that underwent direct bonding with control group.

Abstract: Aims: The aim of this study was the analysis of intensity in different light cure units used in dentistry. Materials and Methods: Four types of light curing sources units; ULTRA–LITE (LED) Astralis 5 (Halogen), BlueLuxcer.TM (Halogen), Delma (LED), were evaluated for the analysis. Light intensity was recorded at various distances of 0 –16 mm, between the light curing tip and a curing radiometer, and at different times (10, 20, 30 seconds) in low–power and at 5, 10, 20 seconds in high–power. Re-sults: The highest light intensity for the first three types (562 mW/cm2) was obtained by BlueLuxcer.TM – high power when the tip of light curing unit was in contact with a curing radiometer. The light inten-sity for the three types of LCUs decreased significantly (p< 0.05) when the light tip was placed at an angle 700 and distance 0, 2, 4, 6, 8, 10, 12, 14, 16 mm away from the a curing radiometer, and the low-est intensity (38 mW/cm2) was obtained by ULTRA–LITE–LED. But the maximum light intensity for the light cure type Delma–LED, was 772 mW/cm2 and the minimum was 268 mW/cm2 when the light tip was placed perpendicular 900 and distance 0, 2, 4, 6, 8, 10, 12, 14, 16 mm away from the a curing radiometer. Furthermore, no significant differences (p>0.05) were detected between Intensity and vary-ing time at 5, 10, 20, 30 sec. Conclusions: The intensity of the curing light was strongly affected by the angles and distance. The decrease in light intensity was significant (p< 0.05) when the light tip placed at an angle 70° and a way to the aperture of the a curing radiometer, but the magnitude of the intensity it becomes more with the same procedure when the angle was perpendicular 900. The decrease in the light intensity of the light curing units, agree with the inverse square law for the distances 0 to 16 mm. The study found that there was no significant difference (p> 0.05) in light intensity between the light curing tip and a curing radiometer varying with time. This study notice that the intensity of the light cure type LED is less than QTH(Quartz Tungsten Halogen).