effect of different polishing methods and storage media on discoloration of resin composites

Statement of Problem: Accumulation of plaque and staining due to a rough surface, and penetration of colourant agents from food and beverages in to the resin composite results in an incomplete polymerization. There is a little information on the effect of finishing and polishing techniques on the discoloration of nanohybrid and microhybrid composites when exposed to staining solutions

Objectives: To determine the degree of surface staining of nanohybrid and microhybrid composites after polishing and immersion in distilled water and two commonly used staining solutions

Materials and Methods: A nanohybrid [Ice; SDI] and microhybrid [Gradis direct; GC] composites were used. Disc-shaped specimens were prepared and treated with either a matrix finish or polished using Sof-Lex discs [3M/ESPE] and Enhance point [Dentsply]. After 24 h immersion in distilled water at 37[degree sign]C the specimens were polished and colour coefficients [CIE L[asterisk] a[asterisk] b[asterisk]] was measured by a spectrophotometer. All specimens were immersed in 37[degree sign]C distilled water in an incubator for 7 days and colour coefficients were measured again. The colour change [[DELTA]E] was calculated using the following formula: [Delta]E = [[[Delta]a][2]+[[Delta]b][2]+[[Delta]L][2]] [1/2]. The data were analyzed using three-way ANOVA, one-way ANOVA/Tukey HSD and Student's t-test

Results: There was a significant interaction between resin composites, polishing systems and staining solutions [p < 0. 05]. ANOVA and Tukey's tests showed that Ice had a significantly lesser colour change than Gradia direct and matrix finish revealed the smoothest surface followed by Sof-Lex discs and Enhance point. Distilled water and cola caused no perceptible colour change [[Delta]E < 3.3]. The effect of surface polish on staining was statistically significant [p < 0 .05]

Conclusions: Sof-Lex discs in comparison to Enhance point stimulated greater staining resistance for both composites. The nanohybrid exhibited less colour change than microhybrid composite. Coffee was the only storage media that induced a perceptible colour change [[Delta]E > 3.3] compared to cola and distilled water

Investigation of the awareness of the students of Shiraz dental school concerning the patients' rights and the principles of ethics in dentistry

Statement of Problem: Deliberating the patients' rights is one of the major human ethical and legal principles which can be investigated through the agenda of professional and medical ethics accordingly, the students of dentistry have to be educated about this issue and achieve the necessary skills in deliberating and concerning the patients' rights

Purpose: The present study aimed to investigate Shiraz dental students' awareness and attitude regarding the patients' rights as well as the principles of dental ethics in order to design methods for organizing and improving the ethics in dentistry

Materials and Method: The present descriptive-analytical study was conducted on 111 students of different departments of Shiraz Dental School. The study data were collected through a questionnaire designed based on the patients' rights charter in Iran, ADA ethical codes which are internationally acceptable in the field of dentistry, and the guidelines of the ministry of health, treatment, and medical education [No. 140588]. Then, the data were entered into the SPSS statistical software and analyzed

Results: Of all participants, 21.6% were men and 78.4% were women. According to the results, 71% of the students were acquainted with the patients' rights. In addition, the patients' characteristics, including gender and nationality, were not important for 58.6% of the students

Conclusion: The study findings showed that 71% of the participants were acquainted with the patients' rights Establishment of a comprehensive, integrated charter in Iran is needed. With rapid development of medical sciences, new issues appear which necessitate taking into account the mutual rights of the physicians, people, and patients

[ cleaning efficacy of manual files compared with two rotary instruments in the root canal of permanent molars: an in vitro study]

Different rotary NiTi systems have been introduced for root canal cleaning. This study was performed to compare the effectiveness of a manual file [K file] with two rotary systems [ProTaper and Mtwo] for root canal preparation in the first permanent molar teeth. India ink was injected to 140 of 150 mesiobuccal root canals of human mandibular first permanent molars, which were randomly divided into three experimental [including 40 canals] and three control groups [10 canals]. In each of these first, second and third subgroups, either the manual instrument [K-file] or the rotary system [ProTaper and Mtwo] were used to prepare the root canals. Canals in group 4 were irrigated with normal saline. In group 5 and 6 no instrumentation was performed. After clearing the teeth, the root canals were observed with the help of a stereomicroscope and the data were analyzed by SPSS, Kruskal-Wallis and Friedman tests [p<0.05]. There was no significant difference between manual and rotary instruments. There was a significant difference between cleaning of the apical, middle and coronal areas of the canals prepared with K-file with a better performance at the apical area compared with the coronal and middle parts. While there were no significant differences in any of the three root canal regions ProTaper or Mtwo systems. The ProTaper and Mtwo rotary systems showed acceptable cleaning ability and efficacy in permanent molar root canals

[ in-vitro evaluation of the effect of autoclave/formalin sterilization on apical microleakage in obturated human teeth]

The extracted human teeth are commonly used in endodontic research and preclinical education. The center for Disease Control [CDC] recommends sterilizing the extracted teeth by storing in 10% formalin for 2 weeks or autoclaving. The purpose of this study was to determine the potential effect of storage in formalin or autoclaving of the extracted human teeth on the apical seal entegrity of the obturated canals. A total of 83 extracted single-rooted teeth, free of visible fracture, caries of large restoration or rott canal treatment were collected, and temporarily stored in normal saline for no longer than 48 hours before categorizing them in experimental and control groups. The teeth were divided into three experimental groups of 25 each, and placed in 10% formalin for 2 weeks or autoclaved or immediately prepared. Eight teeth served as positive and negative controls. Preparations for all the teeth consisted of decoration, canal instrumentation by protaper system and obturation with lateral compaction technique. The teeth were immersed in India ink and cleared. Then the greatest extent of linear dye leakage was measured. Leakage measurements were evaluated fro significant differences using ANOVA with tukey's HSD Post Hoc analysis. There was less dye leakage in the teeth stored in formalin as compared to autoclaved and freshly extracted teeth. No statistical significant differences in apical microleakage between the three experimental groups were observed [p<0.05]. The results of this study revealed that storage of the extracted teeth for research and educational purpose in formalin or autoclaving had no effect on apical microleakage of the obturated teeth

[Maxillary first molar with a single root and a single canal: a case report]

The aim of this case report is to present an unusual maxillary first molar with a single root and a single canal. The significance of this case is that, according to most endodontics and dental anatomy textbooks, the human maxillary first molar usually has three roots and three or four canals. Based on our literature search, this case report is the second reported maxillary first molar with single root in the world and the first in Iran. A 42 years old lady with acute pulpits of the left maxillary first molar was referred to our clinic. The probability of the presence of single root and single canal of the first molar was considered based on her panoramic view. Access opening revealed a single wide canal orifice extending from buccal to lingual side. The presence of a single root and canal was proved by preparing several periapical radiographs with different horizontal angulations during root canal therapy

[Comparative evaluation of manual and rotary techniques on cleaning ability and instrumentation time in deciduous molars]

New Ni-Ti rotary instrument systems have been designed for ease of canal preparation in permanent teeth. Evaluation of the ability and effectiveness of such newely introduced devices in pulp treatment of deciduous teeth seems to be logic and necessary approach as well. The purpose of this study was to compare the manual [K-file] and rotary [protaper] techniques on cleaning ability and instrumentation time in deciduous molar teeth. After injection of Indian ink into root canals of 49 teeth of 56 selected deciduous molars, the teeth were randomly devided into three experimental groups [14 teeth and 42 canals in each], and two control groups [each of 7 teeth and 21 canals]. Canal preparations were done manually [K-files] in group one, and by protaper rotary files in group two. In group three canals were only irrigated with normal saline, but no cleaning or irrigation of the canals were done in groups four and five [control groups]. Instrumentation time was recorded for groups one and two. After clearing procedure, canals contents were observed with a stereomicroscope at X10 magnification, and results were analyzed using T-test, ANOVA and Tukey HSD test. Mean cleaning amount of apical, midle and coronal thirds of the canals for protaper rotary files group [two] was more than that of manual K-files group [two] and normal saline group [three]. The differences between groups one and two and groups two and three were statistically significant [P<0.001]. Mean cleaning amount of all parts of canals for K-file manual instrumentation group [one] was more than that of normal saline group [three]. Statistical difference between groups one and three was also significant [p<0.001]. mean recorded instrumentation time in group two [rotary protaper group] was 70 seconds, while it was 130 seconds for manual K-file instrumentation group [p<0.001]. results suggest that rotary protaper can efficiently be used for endodontic treatment of deciduous teeth

[Control of blood pressure morning surge in a lebanese hypertensive population]

The primary endpoint of this prospective clinical study is to ascertain the degree of blood pressure control in the early-morning hours after 8 weeks of treatment with telmisartan in hypertensive patients using home blood pressure measurements. Two hundred forty Lebanese patients with uncontrolled hypertension are enrolled in the study. The blood pressure is measured at the initial visit, then at week 4 of follow-up [optional visit] and after the 8 weeks period, by the physician at his office [with pulse rate] and by the patient at home in the morning. The blood pressure measured by the patient at home in the morning has a mean value of 129.7/79.1 mmhg, significantly less than 135/85 mmhg [P< 10[-5]], and it is reduced by 31.9/13.5 mmhg [P< 10[-5]]. At the physician's office, the reduction is 34.8/16 mmhg [P< 10[-5]. Heart rate is decreased by 4.7 +/- 0.5 bpm [P< 10[-5]. The drug was well tolerated. This study has demonstrated that Telmisartan, by his long half-life, protects the patients against the early-morning hours blood pressure surge, period during which coronary and cerebral events are the most frequent