Journal of Dental Medicine

Background and Aims: The objective of the present study was to investigate knowledge and attitude of senior dental students towards HIV/AIDS. Its result could help in promotion of education.

Materials and Methods: This educational research was carried out in two state dental schools in Tehran. The senior dental students in Tehran and Shaheed Beheshti dental schools were asked to fill in a self-administered questionnaire regarding their age, gender, parents' job, knowledge and attitudes towards treatment of patients with HIV/AIDS in Autumn semester 2007. Fifty five dental students (83%) including 27% male and 73% female in Shaheed Beheshti and fifty five dental students (85%) including 34% male and 66% female in Tehran dental schools were participated. The score for knowledge and attitude of the students were calculated separately. The data were analyzed using Independent sample t-test.

Results: The mean percentage of knowledge and attitude scores were 76.5% (at rang 1-3) and 50% (at range 1-5), respectively. Nearly all of the students believed that all patients should be considered as HIV positive in dental practice, while 49% preferred to refer HIV positive patients. Knowledge and attitude of students were not significantly associated with the gender and knowing HIV positive person (P>0.05).

Conclusion: There is a need to improve knowledge and attitudes of dental students towards HIV/AIDS. It is suggested to emphasize on this subject in dental schools curriculum in Iran.

Background and Aims: The present study aimed to evaluate the barriers to the production of scientific dental articles in dental schools in Iran based on the opinions of dental postgraduate students.

Materials and Methods: A self-administered questionnaire was distributed among postgraduate students of all Iranian dental schools in June 2010. The respondents rated their agreement with eight sentences about what hinder them from producing scientific dental articles based on a 5-grade Likert scale. The data were analyzed using Chi-square test.

Results: Totally, 270 filled questionnaires from 14 dental schools were received. Of all respondents, 53% were male, the mean age were 29.6 ± 3.8. About half of the respondents reported at least one published article. Less than half of the respondents reported producing an article from undergraduate thesis more women than men and more younger than older students (P<0.03). About two-third of the respondents rated absence of an English editing center, no financial incentives, no appropriate environment, and no competency for scientific writing as most prevalent barriers to the production of scientific dental articles.

Conclusion: To expand the share of Iran in the production of scientific dental documents, the potential of postgraduate dental students must be regarded and suitable condition for scientific writing must be provided. Specifically, based on the findings of the present study, provision of an English editing facility, establishing financial incentives, and providing the students with appropriate environment and efficient scientific writing education are of utmost importance.

Background and Aims: Normative need assessments should be substituted or integrated by patient-based outcome measures regarding their shortages in health-oriented approach . This study aimed to assess and compare the ability of  an index of oral health-related quality of life measured by Child Oral Health Impact Profile (COHIP) questionnaire and the Aesthetic Component of Index of Orthodontic Treatment Need (AC-IOTN) to identify the normative need to orthodontic treatment using Dental Health Component-IOTN in a sample of the Iranian adolescents.

Materials and Methods: Target population of this cross-sectional analytic study was 597 of the 13 to 18 year-old schoolchildren enrolled in middle and high schools of the city of Isfahan, Iran. They completed the COHIP questionnaire and then were examined by two calibrated trained dentists (agreement coefficient:0.9) to record the DHC grading. The students scored their AC in according to the images of the scale. The association between subjective indicators and clinically defined need were evaluated by the correlation analysis and the statistics for the diagnostic validity of tests.

Results: Of 568 examined students, 16.7% and 2.1% had definite need according to DHC and AC criteria, respectively. 10% of orthodontic patients had perceived distinct impact on their quality of life. The significant association (P=0.001) between the severity of malocclusion and quality of life was at moderate level by AC (R=0.37), but it was not convincing enough by DHC (R=0.16). The specificity of AC to detect the healthy ones showed to be excellent but its low sensitivity disabled the recognition of patients, precisely.

Conclusion: The considered patient-based indices did not meet the competencies to define the orthodontic need in the adolescents, but it could be employed to identify the persons with impaired quality of life and it would probably benefit  the process of prioritization.

Background and Aims: The aim of this study was to measure the degree of conversion (DC) of three types of composite resins (micro-hybrid, nano-hybrid and Ormocer) with different light curing units (LED LCU and QTH LCU) in two depths.

Materials and Methods: Three commercially available dental resin composites were used in this study: (Tetric Ceram, Ivoclar Vivadent, Liechtenstein-A2 shade), (Tetric Evoceram, Ivoclar Vivadent, Liechtenstein-A2 shade), (Ceram X, Dentsply, Germany-M₂ shade). Specimens were divided into two groups, 5 specimens were photo-activated by QTH unit (Coltolux 75-Colten) and the other five specimens were cured by LED (Demi-Kerr). Then each specimen was sectioned at the top surface and at 2-mm depth. The DC was measured by FT-IR
(Bruker-tensor 27). The data were analyzed by 3-way ANOVA test.

Results: There was significant difference between tested composite resins (P<0.001). The results of top surfaces were significantly different from those observed at 2-mm depth (P<0.001). The type of curing unit affected the polymerization of Ceram X resin composite.

Conclusion: This study showed a significant difference in the degree of conversion in different thicknesses within three groups of resin composites.

Background and Aims: Periodontitis is one of the most common oral diseases with the various incidence rates in different populations. A number of bacteria are considered as the major etiologic agents of periodontitis. The aim of the present study was to determine the prevalence of periodontopathogen bacteria in patients using both PCR and culture techniques.
Materials and Methods: In this study, one-hundred patients (including 62 females and 38 males with an average age of 49±11.5 years) with adult periodontitis referred to periodontics department of School of Dentistry/Tehran University of Medical Sciences were investigated. The samples were taken and sent immediately to the laboratory for culture and molecular evaluation. The PCR was performed using specific primers and the statistical analysis of data was performed using SPSS statistic software and McNemar test.
Results: The results demonstrated that the total detection rate in culture method was 64%. The rate of Aggregatibacter actinomycetemcomitans (Aa) was 28% which was significantly higher than that of Porphyromonas gingivalis (Pg) (6%) and Prevotella intermedia (Pi) (3%). 27% of cases showed mixed bacterial growth. 65% of patients were positive using molecular method. The rate of Aa (30%) was significantly higher than that of Pg (7%) and Pi (5%). The mixed PCR positive rate containing of Aa, Pg and Pi was (23%).
Conclusion: In this study, it was found that most of the bacteria isolated using culture and molecular methods were Aa, Pg and Pi, respectively. Although the detection frequencies of both techniques were similar, the specificity, sensitivity and bacterial detection speed of the PCR technique is obviously higher. Therefore, the use of molecular techniques is strongly recommended. However, both techniques seem to be suitable for microbiological diagnostics.

Background and Aims: The aim of this study was to investigate the prevalence of diabetes and other risk factors in patients with dental infections.

Materials and Methods: A cross-sectional study was conducted among 50 patients who preferred in maxillofacial word of shariaty hospital with acute dental infections in 9 months. A self-administered questionnaire was administered during a dental appointment in order to gather demographic information and recorded past history of systemic disease, OPG radiography, gingival examination, and the result of lab tests such as CBC , FBS , PT, Bilirubin , Creat, T3, T4, TSH, HIVAb and HBSAg.

Results: 28% of the subjects and diabetes, 28% Anemia, 4% Hepatitis and 4% suffered from thyroid deficiency. 28% were smokers and 18% declared using alcohol. 6% of this population was addicted to narcotic substances. There was a significant correlation between age, education, diabetes and dental infections (P<0.05). DMFT for people with dental infections without any systemic disease were 8, for diabetic patients, smokers and alcohol users were respectively 17.16, 17 and 14.

Conclusion: Diabetes found highly prevalent in patients with dental infection and high DMFT.It indicates a need to establish a comprehensive oral health promotion program based on whole examination and blood glucose control in diabetic patients who have acute dental infection by collaboration between dental and general health care professionals. Moreover, it is recommended that all patients should be educated in dental and oral health for prevention of dental infections.

Background and Aims: Different mechanisms have been developed for connecting abutment to implant. One of the most popular mechanisms is Tapered Integrated Screw (TIS), which is a Tapered Interference Fit (TIF) with a screw integrated at the bottom of that. The aim of this study was to investigate the mechanism of TIS and effective factors in employing TIS during design and implementation processes using an analytic method.

Materials and Methods: Relevant equations were developed to predict tightening and loosening torques, contact pressure and preloads with and without bone tissue in this analysis. The efficiency is defined as the ratio of the loosening torque to the tightening torque. The effects of the change in elastic modulus and thickness of the bone on operation of this mechanism were investigated.

Results: In this study, 14 independent parameters such as taper angle, friction coefficient, abutment and implant geometry that are effective on performance of TIS mechanism were presented. The role of some factors was shown in the performance of ITI implant using sensitivity analysis.

Conclusion: It was shown that friction coefficient, contact length, and implant radius play major roles on tightening and loosening torques and efficiency of the mechanism. Furthermore, the results revealed that the change in the elastic modulus and thickness of the bone influenced the efficiency of the mechanism less than 15%.

Background and Aims: Polymerization shrinkage in Methacrylate-based composite is one of the most important factors in composite restorations failure. Silorane-based composite is introduced to compensate this drawback and claimed to have low shrinkage. The aim of this study was to evaluate the polymerization shrinkage of these two composites.

Materials and Methods: In this experimental study, 5 disk shape samples for each resin composites were placed in the centre of metallic ring bonded to microscopic glass slab. Top surface of ring was covered by a glass cover slip. Glass slab and sample were placed on a special LVDT holder in order to light cure from bottom surface and to measure the polymerization shrinkage. In this study, Deflecting Disk method and LVDT (linear variable differential transducer) was used for dimensional change measurement of resin composites. In this study, two LED curing units were used for composite polymerization.

Results: The mean of polymerization shrinkage in Z250 cured with LED and High Power LED was 11.15±0.08µm and 11.51±0.17µm, respectively (P=0.094), and in P90 cured with LED and High Power LED was 1.08±0.06µm and 1.16±0.12µm, respectively (P=0.019).

Conclusion: Silorane-based composite (P90) showed significantly less polymerization shrinkage than that of methacrylate-based composite (Z250). For the two types of composite, there was no significant difference between the two curing units in polymerization shrinkage.

Background and Aims: Regarding the diversity of reported low- back pain among dentists in different countries and lack of control group in most of the previous studies, the purpose of this study was to compare low- back pain and related risk factors between male general dentists and pharmacists to determine the relation between dentistry and development of low back pain.

Materials and Methods: In this cross-sectional study, 261 male dentists were compared with 193 male pharmacists as a control group with Standardized Nordic Questionnaire (low back section). Subjects were at least one year in clinical practice after becoming qualified and did not suffer from connective tissue diseases and history of a traumatic event causing fracture in spinal column. The data were analyzed by Chi- square, T-test and logistic regression analyses.

Results: The prevalence of low back pain in the past 12 months was 54.8% in male dentists and 36.3% in male pharmacists (P=.001). Logistic regression analyses, adjustmenting for occupation, age, body mass index (BMI), smoking, working years and working hours per week, revealed that there was a significant association between being a dentist and having low- back pain (OR=2.54, P=0.001).

 Conclusion: Dentistry as a profession in male gender is associated with low back pain, independent of age, body mass index (BMI), smoking, working years and working hours per week.

  Background and Aims: The purpose of this study was to evaluate the tissue responses to octacalcium phosphate (OCP) and calcium hydroxide (CH) used as direct pulp capping (DPC) materials in cat teeth.

  Materials and Methods: 72 premolar teeth of 9 cats were selected and divided into 3 groups (Two experimental and one control group). After the cats had been anesthetized, the pulp were exposed and capped directly with OCP, CH or no capping material as control group. The cavities of all three groups were filled with Glass ionomer cement (GI). Histological evaluations were performed at two, four and eight weeks after pulp capping. After tissue preparation procedures, paraffin blocks were prepared. After preparation and staining of the sections, the relevant variables were measured by optical microscope. The results were analyzed using Mann-Whitney U and Chi-square tests ( α =0.05).

  Results: Two weeks after pulp capping, all specimens in three groups showed mild to sever inflammation. The formation of hard tissue (dentinal bridge) at in the exposed areas of the experimental groups was more noticeable for calcium hydroxide than that of octacalcium phosphate group. These differences were statistically significant (P<0.001). At four weeks, hard tissues were observed in both groups which were more evident for the CH group and there were statistically significant difference between two experimental groups (p<0.003). At eight weeks, continuous hard tissues were observed in both groups and there were no statistically significant difference between them (P>0.05), but hard tissues continuity were better for in the OCP than that of the CH.

  Conclusion: It seems that the formation of hard tissue in CH because of its porosities had a worse percentage in sealing of the pulp than the OCP .

  Background and Aims: The purpose of this study was research on a new herbal compound (Seidlitzia Rosmarinus) made by Traditional Medicine Research Group, University of shahed to find a safer alternative to HCL-Pumice compound technique.

  Materials and Methods: In this randomized clinical trial seventy two anterior teeth from 9 patients were divided in to three groups according to fluorosis severity: mild (34 teeth), moderate (14 teeth), and sever (24 teeth). In each patient, half of the teeth were treated with “Shahed” compound and other half treated with HCL-Pumice compound. Before and after treatment, photographs were taken in both groups. HCL-Pumice treatment compound was applied for 30 seconds periods and continued for 10 minutes if necessary. In case of herbal Shahed compound the time was determined by clinical symptoms or when labial contour was dismissed, If the result was not esthetistically acceptabale for the patient, HCL-Pumice compound was applied on teeth. NaF was applied after mouth washing. The photographs of the teeth before and after treatment were reviewed by two experienced observer unaware of the treatment modality. The results were analyzed using willcoxon^’s, kruskal-wallis and scheffe test.

  Results: There was over 81.3% acceptance between two observers and no significant differences in intraobservers evaluation (P>0.05). Improvement in beauty indexes were observed in all degrees of dental fluorosis by 18% with HCL-Pumice compound application, but “Shahed” herbal compound induced significant reduction in the amount of white spots in mild fluorosis and stain intensity of moderate fluorosis (P<0.05) , while the reduction in the severity of discoloration in group 2, these two techniques were statistically equivalent but in the remainder, HCL-Pumice compound was more significantly effective (P<0.05) .

  Conclusion: HCL-Pumice compound reduces the severity of the discoloration of the teeth. Shahed herbal compound cannot reduces the discoloration like as HCL-Pumice compound.

  Background and Aims: Along with the advances in dental materials and invention of new techniques for ceramic producion, the demand for the beauty and matching restoration’s color with patient’s natural teeth is growing. Nowadays, zirconia systems are the focus of attention. Despite their strength, one of the problems with such systems is the high opacity and failing to provide the favored color. Considering few studies about the influence of shading on Zirconia, the purpose of this in vitro study was to evaluate the effect of different shading of zirconia-based ceramics on the biaxial flexural strength .

  Materials and Methods: In this in vitro experimental study, Rainbow (Dentium, Korea) zirconia-based ceramics (the diameter of 15mm and 1mm in thick) were divided into four groups of 10 specimens. According to Vita shade guide system and manufacturer’s time recommendations (3 seconds), three groups of disc specimens were shaded to A3, B3 and D3 colors and other ten specimens remained uncolored as control group. The biaxial flexural strength test of discs was evaluated and the elements’ composition of colors was detected by Energy Dispersiue X-ray Microanalysisd (EDX). Finally, data were analyzed using one-way ANOVA and Post-hoc tests.

  Results: The biaxial flexural strength in non colored specimens, A3 shaded discs, B3 shaded, and D3 shaded specimens were determined 1061.93, 819.16, 1100.10, and 825.48 MPa respectively which was statistically significant among groups (P<0.001). The statistical analysis revealed that the highest strength in B3 and non colored groups which were significantly higher than A3 and D3. EDX analysis showed significant differences among different colored compositions.

  Conclusion: The biaxial flexural strength of zirconia cores are affected by shading and the specific selected color.

  Background and Aims: Different adhesives with different solvents may have different solvent evaporation rates. The purpose of this study was to evaluate the solvent evaporation in the self etch and total etch adhesive in different air drying times.

  Materials and Methods: Five adhesives were used in this study: Excite, Prime & Bond NT, UNO, Single Bond, SE Bond Primer. Twelve drops of each adhesive were used for each period of air drying (5, 15, 30 sec). The percentage of mass loss was measured during each test. Data were analized using two-way ANOVA and Tukey.

  Results: Acetone base adhesives showed more loss of mass than other adhesives (P<0.01). P&B NT showed more loss of mass than other adhesives in all air drying times (P<0.01). Adhesives showed different evaporation rates in different air times (P<0.01).

  Conclusion: Adhesives with acetone/water or alcohol/water solvent shows more stable behavior in comparison with adhesives containing pure aqueous solvents.

  Background and Aims: Metallic nano-particles show exclusive biological, chemical and physical characteristic. The purpose of this research was to evaluate the effect of various amounts of nanosilver incorporation (0 (as control), 20, 40, 80, 120, 200 ppm) on the mechanical Properties ( compressive and flexural strength) of resin modified Glass ionomer Cement.

  Materials and Methods: Based on ISO 4049 and ISO 9971 for polyalkenoid cements, 90 cases in each group were prepared for the flexural and compressive strength. Specimens in 6 groups with different amounts of nanosilver (20, 40, 80, 120 and 200 ppm) and control (Fuji II LC improved), stored in distilled water at 37 ° C for 1 day and 30 days. Flexural strength, using a three-point bending method, Modulus of elasticity and the compressive strength were measured by universal testing machine (Zwick) with crosshead speed of 0.5 mm/min. Data were analyzed using two-way ANOVA and Tukey post HOC test.

  Results: The flexural strength and modulus of various amounts of nanosilver incorporation of resin modified glass-ionomer cement were not significantly different (P>0.05). The compressive strength of incorporating of
20 ppm compared with control (P=0.01), 40 ppm (P=0.02) and 80 ppm compared with control (P<0.001) were increased. The flexural strength and compressive strength of Fuji II LC, containing nanosilver particles were increased after 1 day and 1 month significantly (P<0.001).

  Conclusion: Incorporation of 20 to 80 ppm nanosilver into Fuji II LC had increased mechanical properties compared to the original cement.

  Background and Aims: Iatrogenic damage to adjacent tooth during proximal cavity preparation is one of the most common side effects in operative dentistry. The aim of this study was to determine prevalence of iatrogenic damages to adjacent tooth during the preparation of proximal Class II cavities among undergraduate students at dental faculty of Tehran University of Medical Sciences in 2010 .

  Materials and Methods: 106 posterior permanent teeth which had Class II decay with sound proximal surfaces of adjacent teeth were selected and restored by dental students awarding the aims of the present study. After finishing restoration, proximal surfaces were completely dried by air and evaluated with dental chair light. In doubtful cases, surfaces were evaluated with × 3 magnification. Damages were classified into 2 groups abrasion and groove. Data were analyzed using Fishers exact and Pearson chi square tests .

  Results: The frequency of adjacent surfaces damage were 57.5%, with 31.1% damages as abrasion and 26.4% as groove. Students who used matrix band and wedge in proximal area as preventive instruments showed 53.4% damages and other students showed 57.3% damages (P>0.05). A significantly higher number of females and students at restorative course level (3) used wedge and matrix band than males and students at restorative course level (4) for protecting adjacent teeth (P<0.05).

  Conclusion: According to the high percentage of iatrogenic damages on adjacent sound teeth in class II cavity preparation, teaching of preventive methods and using proper techniques is necessary for dental students as future dentists.

  Background and Aims: Retention and stability of the post and core system is the key factor for success of final restoration . The aim of this study was to evaluate the microtensile bond strength of the different composite core materials and bonding systems to a fiber post.

  Materials and Methods: To evaluate the bond strength of the composite resins to a fiber post ( DT light post) 60 posts were divided into six groups : group A: Heliomolar Flow + Seal Bond, group B: Heliomolar Flow + SE Bond , group C: Valux Plus + Seal Bond , group D: Valux Plus + SE Bond , group E: Corecem + Seal Bond, group F: Corecem + SE Bond. All samples were thermocycled for 5000 cycles (5-55 ⁰C) and cut into four bars for the microtensile bond strength test. Failure modes were identified using a stereomicroscope. Data were analysed using One-way ANOVA and Tukey HSD post hoc test (P<0.05).

  Results: The interaction between composite resin materials and bonding systems were positive. The conventional hybrid composite (Valux Plus) had significantly higher bond strength compared with the core specific flowable composite (Corecem) when Seal Bond was applied as bonding agent (P<0.05). However, when SE Bond was utilized hybrid composite demonstrated significantly lower bond strength than that of other two groups (P<0.05).

  Conclusion: The performance of a particular composite is affected by the bonding system that is applied. A single composite resin may have different bond strength when combined with different bonding system.

  Background and Aims: Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to root resorption of the adjacent tooth. The purpose of this study was to determine this resorption using panoramic and periapical radiographs.

  Materials and Methods: In this cross-sectional descriptive study 54 patient (28 men, 26 women) above 15 years old with the average of 22 years in Oral and Maxillofacial Department of Tehran University were studied. A periapical radiography from the third molar and a panoramic radiograph were taken from each patient (Because of their routine use and evaluation of accuracy of panoramic compared with periapical), and the magnitude of the root resorption for the second molar was determined by 2 observers and written in a questionnaire. Data were analyzed using Fisher test.

  Results: The prevalence of the root resorption of the second molar adjacent to the impacted third molar in the panoramic and the periapical radiographies, with respect to the limitation of the sample size were 46.3% and 31.5%, respectively, with 95% confidence(P>0.05). Most of these resorptions were in the cervical third of the second molar roots and in cases in which the third molars were mesially oriented or horizontal. There was also no significant difference between panoramic and periapical radiographs.

  Conclusion: Due to the increased risk of the resorption of the second molar adjacent to the third molar, extraction of the impacted third molars, especiall y mesially oriented or horizontal ones are recommended.

  Background and Aims: Hydroxyapatite coating has allocated a special place in dentistry due to its biocompatibility and bioactivity. The purpose of this study was to evaluate the relation between the hydroxyapatite thickness and stress distribution by using finite element method.

  Materials and Methods: In this paper, the effect of hydroxyapatite coating thickness on dental implants was studied using finite element method in the range between 0 to 200 microns. A 3D model including one section of mandible bone was modeled by a thick layer of cortical surrounding dense cancellous and a Nobel Biocare commercial brand dental implant was simulated and analyzed under static load in the Abaqus software.

  Results The diagram of maximum von Mises stress versus coating thickness was plotted for the cancellous and cortical bones in the range between 0 to 200 microns. The obtained results showed that the magnitude of maximum von Mises stress of bone decreased as the hydroxyapatite coating thickness increased. Also, the thickness of coating exhibited smoother stress distribution and milder variations of maximum von Mises stress in a range between 60 to 120 microns.

  Conclusion: In present study, the stress was decreased in the mandible bone where hydroxyapatite coating was used. This stress reduction leads to a faster stabilization and fixation of implant in the mandible bone. Using hydroxyapatite coating as a biocompatible and bioactive material could play an important role in bone formation of implant- bone interface.

  Background and Aims: Electric pulp tester is a valuable instrument to examine tooth’s pulp vitality. There is no agreement about the response of immature teeth to electric pulp tester and the reason is expressed as the failure of nerve fibers’ development. The aim of this study was to investigate the effect of patient’s age on the tooth response to electric pulp tester.

  Materials and Methods: In this cross-sectional study, 300 maxillary central permanent teeth in 150 volunteers were examined by using electric pulp tester. The volunteers were classified in 5 age groups of 7-8, 9-10, 11-12, 13-4, and 30-35 and teeth lacking sound and healthy pulp were excluded. Data were analyzed using SPSS-16 software, one-way analysis of variance, and Tukey post hoc test.

  Results: The average response to electric pulp tester in age groups of 7-8, 9-10, 11-12, 13-4, and 30-35 years old were 2.9±0.1, 2.8±0.1, 2.3±0.1, 2.2±0.1 and 1.8±0.1 ,respectively. This indicated that by increasing teeth age, they responded to lower level of electric pulp tester. In subjects less than 14 years old, there was no significant difference between neighboring groups (P=0.3) however, a significant difference was observed between subjects less than 14 years old and adults (P<0.001).

  Conclusion: This study showed that immature teeth responded at higher levels to electric test however, all teeth responded to electric pulp tester.

  Background and Aims: Root canal therapy is one of the most important parts of a general dentist's profession. The aim of this study was to evaluate the radiographic quality of root canal therapy performed by under graduated students at Yazd dental school.

  Materials and Methods: Records of patients, who were referred to the endodontic department during 2010-2012 and treated by undergraduated students, were divided into three groups by the numbers of canals and 80 specimens from each group were randomly evaluated. For the assessment, the quality of accomplished treatments, the indices: length, taper, and density of obturation were used and the errors during root treatment were recorded. Data were analyzed using Fisher's exact test and Chi-square.

  Results: According to the results, 155 (64.6%) records had appropriate filling length, whereas 55 (22.9%) were underfilled and 30 (12.5%) were overfilled. The acquired difference was statistically significant among three groups. (P<0.001). 187 (77.9%) records had adequate taper and 157 (65.4%) records had adequate density. The difference in the evaluating of taper (P=0.976) and density (P=0.879) was not significant. Totally, 39.2% of specimens had all the properties of an appropriate root canal treatment.

  Conclusion: The results of the present study can be used to identify weaknesses in the treatment of different educational groups and help them to achieve a proper planning to improve the quality of endodontic treatments.