Introduction: The aim of this study was to investigate the fraction rate of PRO TAPER Universal and Neoniti rotary files during the preparation of simulated severely-curved root canals.Materials & Methods: A total of 70 resin blocks with simulated severely-curved canals were randomly divided into two groups and prepared with PRO TAPER Universal and Neoniti files. Each set of files was used for cleaning and shaping five canals; the files were sterilized after each application. Afterwards, the number of deformed and fractured files was recorded.Results: Deformation was reported in 11.4% and 19% of PRO TAPER and Neoniti files, respectively (P>0.05). Also, fraction was found in 11.4% of PRO TAPER files, while no fracture was reported in the Neoniti group; overall, no statistically significant difference was found between the groups (P>0.05).Conclusion: Based on the present findings, there was no significant difference between PRO TAPER Universal and Neoniti files with respect to the incidence of deformation or fracture during the preparation of severely-curved canals.

Background and Aim: Very little is known about the fracture resistance of endodontically treated teeth restored with different design of esthetic post systems. The aim of this study was to compare the fracture resistance and failure mode of endodontically treated teeth restored with two different types of quartz fiber post.Materials and Methods: In this experimental, in-vitro study, twenty mandibular premolars with similar size were chosen and randomly divided into 2 groups (n=10). After cutting the crowns and endodontic therapy, the teeth were restored with a quartz fiber single TAPER light-posts in group A and quartz fiber D.T light-post in group B. All posts were cemented with a dual cure cement. Composite resin cores were built up using a pre-formed polyester matrix and every specimen was embedded in an acrylic resin block with a layer of elastic polyether Impergum surrounding the roots as PDL. Compressive load was applied at 135 degree angle to the long axis of the tooth at a crosshead speed of 1mm/min until fracture occurred. T-test was used to determine the significance of the failure load values between the two groups.Results: There was no significant statistical difference in fracture resistance among two groups. The fracture load in groups A and B were 366.7±102.7 (N) and 382.4 ±67.3 (N) respectively. (P<0.6).Conclusion: According to the findings of this study, two different designs of quartz fiber posts did not influence the fracture resistance of endodontically treated teeth.

Background and Aims: According to the common application of non-metal prefabricated posts in dentistry and lack of enough information about the stress distribution in the root canal walls by these posts, this study was performed to compare the effect of two simple TAPER and double TAPER posts on the stress distribution on root canal walls by photo elastic method.Materials and Methods: The design of this study was experimental in photoelastic system. The posts, used in this investigation, were double TAPER and simple TAPER fiber posts with 0.9 mm diameter and 20 mm length and epoxy resin. First two photo elastic models with tooth dimensions were fabricated and the posts were placed inside the model. Then the core of the each post was fabricated on the model. Each models were loaded in polariscope and the formed fringe order colored ring were photographed.Results: In 100 N, 90 degree angle loading in cervical and apical fringe order showed 2.50 and 1.39 in simple TAPER posts and 1.39 and 2.35 in double TAPER post. In 150 N, 30 degree angle loading in cervical and apical fringe order showed 4 and 2.65 in simple TAPER posts, and 4 and 2.5 in double TAPER post.Conclusion: In the vertical and oblique loads, double TAPER fiber post showed better stress distribution than that of simple TAPERed posts.

Statement of PROblem: Canal preparation is one of the most important and time- consuming steps in endodontic treatment of primary teeth. Regarding the difficulties in behavior management of some children, rotary (nickel-titanium) files PROved more facilities and speed and hence more success in the root canal treatment of primary teeth.Purpose: The purpose of the present study is comparison of the success rate and cleaning time of pulpectomy in necrotic primary molar teeth using manual and rotary instruments.Materials and Methods: In this study which is an interventional in vivo clinical trial, 40 patients, mean age 5.7+0.92, were randomly selected and divided into two equal groups (I, II). In the first visit, pulpotomy of the necrotic teeth was done for all of the cases. In the second appointment after local anesthesia and isolation of the teeth with rubber dam, preparation of the canals was done with PRO-TAPER nickel-titanium files (S1, S2, F2) in the first group and with stainless steel manual K-files (10-30) in the second group. The total time needed for debridement was calculated exactly by chronometer. The canals were then filled with ZOE by using lentulo spirals and periapical radiography was prepared for all of the cases. The patients were followed-up in 3 and 6 months intervals and the statistical analysis were done by Non-Parametry Mann-Whitney test.Results: The success rates of manual and rotary instruments were 85% and 90% respectively after 3 months. The success rate of the two groups (I, II) was 100% after 6 months follow-up and all of the signs and symptoms including pain abscess, and fistula and perapical radiolucency disappeared. The time needed for canal preparation was calculated 4.12 minutes (251.75±32.58 seconds) with PRO-TAPER and 9.21 minutes (563.05 ± 70.03 seconds) with manual instruments. The difference was statistically significant.Conclusion: The success rate of manual and rotary instruments was 100% in both groups but the preparation time (which is an important clinical factor for patients management) significantly reduced using rotary instruments. Hence, pulpectomy of the primary teeth using rotary instruments (PRO-TAPER files) is recommended for root canal treatments in children.

The non-overt subject of the infinitive clause is represented by the element PRO, an NP which appears to be syntactically active without overt manifestation. Although PRO is a part of architecture of GB, no coherent account of this element can be found in Persian. The stipulation of PRO by Iranian grammarians both traditional and modern has been in vain due to two dilemmas: first the nature of non-finite clause in Persian, and second, finding ungoverned position for PRO. After all, syntactic, semantic and morphological behavior of Masdsar in Persian supports its constituency nature in favor of being a non-finite clause. Subsequent to introducing the non-finite clause in Persian, there will be a room to account for the existence of PRO. Of considerable importance is the justification that non-finite clauses are CPs not IPs, which makes it possible to find an ungoverned position for the distribution of PRO.

For the study of atomic systems, first introduced by Feichtinger et al. Gavruta presented K-frames on Hilbert spaces. K-frames are a kind of frames in sense that the lower frame bound only holds for the elements in the range of the K, where K is a bounded linear operator in Hilbert space. C*-algebra whose topology is induced by a family of continuous C*-seminorms instead of a C*-norm is called PRO-C*-algebra. Hilbert PRO-C*-modules are generalizations of Hilbert spaces by allowing the inner PROduct to take values in a PRO-C*-algebra rather than in the field of complex numbers. In this paper, the sequences whose elements are adjointable operators from PRO-C*-algebra into Hilbert PRO-C*-module is called the sequence of multipliers. We introduce the concept atomic systems and K-frame of multipliers in Hilbert PRO-C*-modules and for more information, we give an example of K-frames. We obtain a condition that sequences of multipliers is frame, also we investigate the relationship between atomic systems and K-frames with each other and the frame of multipliers. If K is a bounded operator with certain conditions then every K-frame of multipliers is a frame of multipliers in Hilbert PRO-C*-module. Also, we investigate some of the PROperties of these concepts, such as the combination of operators with K-frames in Hilbert PRO-C*-module.

Background: In serious competitions in order to keep the acquired fitness, athletes are advised to reduce the exercise intensity before starting the races. This technique is called TAPER. The purpose of this study was to compare four usual PROcedures of TAPER and effect of them on the Hematological responses by measuring Vo2 max, hematological and biochemical factors. Methods and materials: Sixty semi PROfessional athletes, 20 to 35 years old with Vo2 max between 30-45 three milts/kg/min were selected. Exercises were in three stages and took for eight weeks. In the first stage, which lastd for 4 weeks athletes did moderate intensity exercise three days a week and 30 minutes a day. Second stage started after the first stage with vigorous exercise three days a week and 45 minutes a day that lasted for two weeks. In the third stage TAPER, the subjects were randomly divided into four groups. The PROgram of the first group was two days week and exercise intensity so was done with 85%, 75%, 65% and 55% of maximum exercise intensity. Second group PROgram was two days a week exercise with 50% of maximum exercise intensity. The third group PROgram was two days a week exercise with gradual reduction of exercise intensity. The fourth group had only rest. At second and sixth weeks after doing PROgressive exercise and TAPER, blood samples were taken from the cases and were sent to a reliable diagnosis lab.Results: Collected data from different TAPER methods were analyzed using repeated measures ANOVA and no significant difference between biochemical factors (P>0.05) was seen but the data showed a significant difference among Vo2 max values after using theses methods (P=0.04). In addition, there was significant difference in hemoglobin, hematocrit, M.C.H, M.V.C, platelets, W.B.C and Vo2 max when measured in second week, sixth week and later on TAPER (P<0.05).Conclusions: According to the results of this study, TAPER III has a considerable effect on semi PROfessional Hematological responses.

Background and Aim: Today several materials have been used for root- end filling in endodontic surgery. Optimal PROperties of PRO Root MTA in in-vitro and in-vivo studies have been PROven. On the other hand, based on some studies, Root MTA (Iranian PRO Root MTA) and Portland cement are similar to PRO Root MTA in physical and biologic PROperties. The aim of this study was to evaluate bacterial leakage (amount and mean leakage time) of four root- end filling materials. Materials and Methods: In this experimental in-vitro study, seventy six extracted single- rooted human teeth were randomly divided into six groups for root-end filling with gray PRO Root MTA, white PRO Root MTA, Root MTA (Iranian PRO Root MTA), Portland Cement (type I) and positive and negative control groups. Root canals were instrumented using the step- back technique. Root- end filling materials were placed in 3mm ultra sonic retro preparations. Samples and microleakage model system were sterilized in autoclave. The apical 3-4 mm of the roots were immersed in phenol red with 3% lactose broth culture medium. The coronal access of each specimen was inoculated every 24h with a suspension of Streptococcus sanguis (ATCC 10556). Culture media were observed every 24h for color change indicating bacterial contamination for 60 days. Statistical analysis was performed using log- rank test with P<0.05 as the limit of significance. Results: At the end of study 50%, 56.25%, 56.25% and 50% of specimens filled with Gray PRO Root MTA, White PRO Root MTA. Root MTA and Portland Cement (type I) had evidence of leakage respectively. The mean leakage time was 37.19±6.29, 36.44±5.81, 37.69±5.97 and 34.81±6.67 days respectively. Statistical analysis of data showed no significant difference among the leakage (amount and mean leakage time) of the four tested root- end filling materials (P=0.9958). Conclusion: Based on the results of this study, there were no significant differences in leakage among the four tested groups at 60 days. The results suggest that Root MTA and Portland Cement can be used as less expensive root filling materials.