Aims:To evaluate the effect of two types of disinfectant solutions(2% alkaline glutaraldehyde, 1% sodium hypochlorite) in wettability of three types of elastomeric impression materials (light body) which are used in crown and bridge restorations at different times of immersion. Materials and methods: Three types of elastomeric impression materials (light body) were formed on a flat acrylic resin block and allowed to set(five specimens of each impression material was done for each immersion time(15,30 and 60 minutes)of each disinfectant solution in addition to control groups). The wettability is indicated by measuring the contact angle of aqueous solution of CaSO4 on surface of cured impression materials. Results: indicated no significant effect of immersion times on wettability of three types of impression materials. The hydrophilic type produce high wettability. Conclusions: The disinfectant solutions have different effects on each impression material. Sodium hypochlorite has the greatest beneficial effect on wettability.

Aims: to determine the effect of colored drinks on the surface hardness of three types of composite restorations. Materials & methods: Three composite resins (a compoglass, conventional and ceramic composites) were used in this study. Transparent disc with 2mm thickness and hole of 5mm diameter were used for the preparation of composite samples, ten samples were made for each type of composite with a total of 30 samples. Four samples from each type of composite were immersed in(a cola ,tea, normal saline and coffee) respectively (normal saline as a control for the study),after that each colored drink measure amount of ph before put the samples using ph meter(Pw 9421,philips) and then each sample stored for (one week, two week and one month) inside incubator at 37° C then the samples were tested for the micro hardness with a Vickers micro hardness tester(Wolpert,Germany)with 200g load. Five micro hardness measurements were obtained on top surface of each sample on the following time period: before immersing in color drinks, after immersing each samples in cola, coffee and tea. Data were analyzed using One way analysis (ANOVA) and Duncan, a value of P≤ 0.05 was considered significant .Results: The results of ANOVA showing a significant difference among all ceramic samples regarding all media and time when P≤ 0.05.Conclusion: it can be concluded that all conventional materials are susceptible to the effect of aqueous media of oral cavity and other softening drink.

Aims: To determine if the composite resin restoration need to be replaced after power bleaching at different times.Materials and methods: Three composite resins (a flowable, a conventional and ceramic composite) were used for this study. Transparent discs with 2mm thickness with a hole of 5mm diameter were used for the production of composite samples, six samples were made for each type of composite with a total of 18 samples were used. The bleaching procedure was followed on the top surface of each sample. For each sample a newly fresh material were mixed (lase peroxide sensy gel) and applied over the prepared sample. Bleaching took place for 15, 30 and 45 minutes according to the manufacturer instructions. For the microhardness measurements, a Vickers microhardness tester (Wolpert, Germany) was used, with a 200g load. Five microhardness measurements were obtained on the top surface of each sample on the following time periods: before bleaching, after 15 min., after 30 min. and after 45 min. of bleaching. Data were analyzed using T-test, a value of p≤0.05 was considered significant followed by the analysis of variance (ANOVA). Results: The results showed a significant increase in the microhardness of all the three types of composite resins after bleaching with a different time when compared to the control.Conclusion The bleaching agent that was tested has a significant increase of the microhardness of the composite resins and there is no sufficient reason to indicate the replacement of restorations.

Aim: To examine the efficacy of chemo-mechanical dentin removal method in vitro. Material and Methods: Forty eight extracted permanent teeth with occlusal caries. The dentin caries of each tooth was removed either with chemo-mechanical method using Carisolv™ or mechanically using round bur. Cutting and caries removal monitored by checking the hardness of dentin with a dental explorer and stopped when teeth in each group showed either a leather hard texture or a sharp scratching sound was heard. The caries activity of the remaining dentin was assessed by using an acid red as a caries indicator. The mean surface areas of the pink zone (caries active, pH <5.5) and yellow zone (caries inactive, pH >5.5), of each caries lesion was calculated using AutoCAD computer software. Result: Revealed that for teeth treated with Carisolv,™ the surface area of remaining carious dentin was significantly more when it compared with teeth that treated mechanically in each group, using unpaired t-test regardless of the clinical criterion for caries removal. Conclusion: Carisolv™ is effective in caries removal when used as chemomechanical caries removal than conventional mechanical method and the mean surface areas of remaining affected carious dentin was more in chemomechanical than conventional mechanical meaning that more tooth structure is preserved using chemomechanical method.

Aims: Different materials are used during endodontically treating of teeth as root canal sealers. Thus, this study was done to evaluate the sealing ability of three different types of root canal sealers on the apical part of the tooth. Materials and Methods: 50 sound human teeth were instrumented by using a rotary ProTaper nickel-titanium files under crown down technique. The samples were divided randomly into 3 groups (n=10), additionally two groups were used as +ve controls, first group usedEndofill sealer (PD product dentairesSA,Switzerland), and group two used Tagadseal sealer (technical general United kingdom),and the third group used AH plus sealer (Dentsply, Switzerland). All teeth were obturated using the single cone technique with the sealers, then the whole root surface was coated with two layers of aspecial type of nail varnish, except the apical 1 mm, then all teeth were placed into 2 % methylene blue dye liquid for one week at 37 o C. After that they were removed from the dye , the nail varnish was removed. The positive controls (n=10) were left unfilled and coated as described earlier. Then the tooth was splited longitudinally and each half examined under a stereomicroscope with magnification: 10 X. A computer software was ued taken by a digital camera. Analyzing of data was done by One-Way Anova and Duncan , s Test analysis among the means of microleakage of the three types of sealers. All tests were computed at 5% significance level.Results: showed statistically significant difference among groups. Group 3 (AH plus) showed abtter seal among ( Tg and Endofill) groups while Tg and Endofill showed no significant difference between both. Conclusions:Under the conditions of this study, the AH plus sealer provided a better sealing ability than Endofill and Tagadseal sealers, but long term in vivo study is important to prove it.