Background and Aim: Because of polymerization shrinkage and high viscosity of posterior COMPOSITEs, there are some difficulties in using them in posterior restorations. Several methods have been represented to reduce the effect of shrinkage. The aim of this study was to investigate the effect of curing flowable COMPOSITEs under CONDENSABLE ones in adaptation and microleakage reduction of posterior COMPOSITE restorations.Materials and Methods: In this experimental in vitro study, forty class II MO cavities were prepared on extracted intact molar and premolar human teeth. Gingival margins were placed 1 mm apical to CEJ. The teeth were divided into two groups. In group 1, flowable COMPOSITE (Filek Flow, 3M, ESPE, USA) with 0.5-1 mm thickness was applied and cured following application of bonding agent (Single Bond, 3M, ESPE, USA). The rest of the cavity was filled by CONDENSABLE COMPOSITE (p60, 3M, ESPE, USA). In group 2 the flowable COMPOSITE was not cured, and the CONDENSABLE COMPOSITE was applied in two increments. After light curing of COMPOSITEs, all the specimens were thermocycled and then immersed in 0.3% basic fuschin. Specimens were sectioned and evaluated for degree of dye penetration under a stereomicroscope. Data were analyzed by Mann-Whitney test with p<0.05 as the level of significance.Results:. There was no significant difference between the two studied groups regarding microleakage. Conclusion: Based on the results of this study, neither cured nor uncured flowable COMPOSITE under CONDENSABLE COMPOSITE can omit microleakage in posterior COMPOSITE restorations.

Posterior COMPOSITE restorations, due to polymerization contraction, result in microleakage. Different methods have presented to reduce this phenomena. The aim of this study is to evaluate the effects of flowable and CONDENSABLE COMPOSITEs to reduce microleakage. Seventy extracted human teeth were prepared with proximal class II cavities with gingival margin 1 mm below CEJ. The teeth randomly were divided into 7 groups. Groups I & II were restored with a dentin bonding (DB) agent plus a Prodigy CONDENSABLE (Kerr Co.) COMPOSITE, placing incremental or bulky, respectively. In groups II, IV, V a dentin bonding agent was applied and then cavities were restored with Tetric flow COMPOSITE resin as a base plus either a hybrid COMPOSITE (Tetric ceram, Vivadent Co.) or a Prodigy CONDENSABLE COMPOSITE (Cond), placing bulky or incremental. Groups VI and VII were restored with a resin modified glass ionomer (GI) (Fuji II Lc Co.) as a base plus either Prodigy CONDENSABLE or Tetric ceram. Restorations were polished, thermocycled, and immersed in 0.3% basic fushin. After that samples were sectioned and studied under a stereomicroscope to evaluate dye penetration. Results showed that all restorations showed some degree of microleakage and according to kruskall- wallis statistical analysis, there were not any significant differences between all groups (P=0.051). Then fore pair comparison, between groups, Mann-Whitney analysis was used and no statistical difference was observed. However, GI+ DB+ Tetric group showed the least microleakage and DB+ Cond (bulk) the most one. Due to lack of any statistical difference among different materials methods, it is concluded that no method or restorative material have been able to eliminate microleakage in margins completely yet, and using a flowable COMPOSITE resin, in place of resin modified glass ionomer or using a CONDENSABLE COMPOSITE, instead of conventional hybrid COMPOSITEs, do not have any effect on microleakage reduction.

BACKGROUND AND OBJECTIVE: The congenital anomaly of nose is the one of causes of cosmetic of face and repair of this defect is very difficult. In this article, it was reported a case of congenital hypo plastic nasal alar with failure in operation two times. CASE: A 19 year old female referred with hypo plastic nasal alar who had been already operated two times with a failure in repairing this defect. A COMPOSITE graft from ear with suitable size was inserted in the defect area of nose and it was improved. CONCLUSION: For repairing this anatomical defect and decreasing failure, this new surgical method is suggested.

Introduction: In spite of improvements in COMPOSITE function, marginal microleakage in deep COMPOSITE restoration is still considered as a challenge due to unstable bond between COMPOSITE and dentin. Therefore, this study aimed to investigate effect of applying different materials on marginal microleakage in posterior COMPOSITE restoration.Methods: A standard distal box was prepared on 80 human premolar. The gingival floors were 1 millimeter under CEJ. The specimens were divided to four groups. In the first group, 1 millimeter amalgam was used as the first increment in proximal box on gingival floor, in the second group flow able COMPOSITE, and in the third group, RMGI were used. Other cavities were filled by CONDENSABLE COMPOSITE. In the fourth group (control), all the cavities were filled only by CONDENSABLE COMPOSITE. The specimens, after 6 months of storage, were placed under cyclic load (10000 cycle- 80 N- 1 Hz), and then were immersed in 2% methylene blue for 6 hours. Afterwards, the specimens were sectioned in the middle of restoration. Extension of dye penetration at the cervical margin was examined under a stereo microscope at 25x magnification and the leakage was evaluated by Fuks degree. The study data were statistically analyzed using the Mann- Whitney U-test (p<0.05).Results: Microleakage was observed in all the groups. The third group demonstrated the most leakage and the least was for the first group. No statistically significant difference was observed between the groups. (p-value=0.689) Conclusion: In cavities with gingival floor under CEJ, different filling methods have no effect on marginal sealing.

The problem of laminar film condensation from binary vapours mixture with the presence of non-CONDENSABLE gas (air) flowing in a vertical tube is numerically investigated. The set of the non-linear parabolic equations expressing the mass conservation, momentum, energy, and species diffusion in both phases with the boundary conditions are resolved by using a finite difference numerical scheme. A comparative study between the results obtained for three cases (water-ethanol-air, water-methanol-air, and ethanol-methanol-air) under the same conditions is made. The impact of varying the wall temperature, the inlet vapour mass fractions, and the inlet liquid mass flow rate on the conjugate the heat and mass transfer during the condensation of the studied mixtures are examined. It is found that the condensation of water-methanol-air corresponds to a higher latent heat flux QL2 and accumulated condensation rate Mr2 when compared with water-ethanol-air and ethanol-methanol-air. Moreover, the nature of the fluid plays an important role in the heat and mass exchanges.

Background and Aim: Considering flexural strength of fiber-reinforced COMPOSITEs (FRC) and also the role of conservative cavities in protecting sound tissue of abutments, the aim of this study was to evaluate the fracture resistance of these bridges by handmade samples in vitro.Materials and Methods: In this experimental in vitro study, 44 sound newly extracted teeth were used to make 22 fixed inlay bridges including 11 three unit anterior upper inlay bridges substituting clinical model of upper central and 11 three unit posterior lower inlay bridges substituting clinical model of lower first molar.Specimens were prepared with FRC and mounted with artificial PDL in acryl. Cases were exposed to final load by using Universal Testing Machine (Instron 1195) with the speed of 1 mm/min. Statistical analysis was performed by Kolmogorov- Smirnov, independent sample T and Kaplan-Meier tests with p<0.05 as the level of significance.Results: Based on the statistical tests, the 95% confidence interval of mean was 450-562 N in anterior and 1473- 1761 N in posterior area. Fracture strength was high in the studied groups. Fractures in both groups occurred on COMPOSITE facing, and the framework remained intact. The highest percentage of fracture in posterior teeth was in the middle of pontic towards the distal connector and in the anterior teeth in the lateral connector, between central pontic and lateral abutment. Using the independent sample T test a significant statistical difference was observed between two groups (P<0.001). The fracture resistance of anterior samples was lower than the posterior ones.Conclusion: Based on the results of this study regarding the high fracture resistance in both areas FRC inlay bridges could be recommended for upper anterior and lower posterior teeth in clinical dentistry certainly more studies are needed to ascertain this treatment option.

This study was accomplished in order to evaluate the of COMPOSITE basing technique (CB.T) on fracture resistance of the teeth restored with porcelain inlays (invitro). Forty sound human maxillary first premolars were divided into 4 groups. Each group included 10 teeth. samples prepared in the following manner: group 1 :prepared and restored without CB.T group 2:prepared but unrestored without C B.T group 3 :prepared and restored with CB.T group 4:prepared but unrestored with CB.T for all groups Instron universal machine were used under compressive load. 1- no significant difference were observed in fracture resistance and fracture mode between teeth that restored (group 1 &3). 2- no significant difference were seen in fracture resistance and fracture mode between unrestored teeth ( group 2&4 ). 3- significant difference were seen in fracture resistance between restored teeth (group 1&3)and prepared but untestored teeth (group 2&4).

A thermo-economic performance optimization has been carried out for a shell and tube condenser TEMA-E. In the considered model, the irreversibilities due to heat transfer between the hot and cold stream are taken into account. The objective function is defined as the actual heat transfer rate per unit total cost considering lost exergy and investment costs. The optimal performance and design parameters which maximize the objective function have been investigated. The effects of the technical and economical parameters on the general and optimal thermo-economical performances have been also discussed. The results show that the objective function increases with increasing heat capacity ratio and decreasing inlet temperature and ambient temperature ratio. The dominant term in entropy generation in this study is due to the heat exchange between the condensed fluid and the cold fluid. According to the operating conditions of the heat exchanger, a correlation has been obtained for the thermal efficiency that maximizes the objective function. Optimal value of the design variables obtained from Pattern search method and the Ant Lion Optimizer method are relatively different at about 0-0.13%; depending on the type of optimization method and its internal operators. But the optimal value of the objective function in both methods is approximately 16.08. The analysis and optimization presented herein may provide a basis for both determinations of the optimal performance parameters for real heat exchanger.