Assessment of suturing and scaling skills of periodontology and oral medicine residents by OSATS method: a pilot study.

INTRODUCTION: Updating the method for evaluating suturing and scaling skills in dental education has attracted relatively little attention and there is no consensus to what should be assessed and how. The purpose of this study was to investigate the applicability of the Objective Structured Assessment of Technical Skill (OSATS) method for these two basic skills, the possible association between the scores and demographic factors, and the level of satisfaction of residents with this method. METHODS: All six periodontics and three oral medicine residents were recruited by census method and video-recorded while performing a simple interrupted suture, a figure eight suture and scaling on a model. Then, the videos were evaluated independently via a checklist and a global rating scale (GRS) by two expert raters. Agreement between raters and residents' satisfaction were evaluated. Correlation between demographic factors of participants and scores was also assessed. T-test and linear regression analysis were used. RESULTS: There was no significant difference between the scores based on the views of the two raters for each of the checklist (ICC = 0.99, CI = 0.96-0.99, P < 0.001) and GRS (ICC = 0.97, CI = 0.86-0.99, P < 0.001). Linear regression showed no correlation between gender and scores but periodontics major and higher year of education showed correlation with higher scores. CONCLUSION: Considering the excellent agreement between raters in using both the checklist and GRS components of OSATS, and satisfaction of 88% the residents with this method, it seems to be able to provide a reliable assessment.

Assessing the occurrence and severity of pre- and postendodontic pain in anemic and healthy female patients.

OBJECTIVES: The objective of this current survey was to assess both the occurrence and severity of pre- and post-endodontic pain among female individuals, distinguishing between those with anemia and those without. MATERIALS AND METHODS: In the current study, we included a total of 60 women with anemia (hemoglobin < 11) and those without anemia (hemoglobin > 13). We recorded the occurrence and severity of pain before and at 24, 48, and 72 h following root canal treatment using a visual analog scale (VAS) ranging from 0 to 10. Additionally, we collected data on patient age, tooth type, as well as pulpal and periapical conditions. Statistical analysis was carried out using two-way ANOVA, pairedt-tests, and Pearson correlation coefficient. The significance level for statistical tests was set at p ≤ .05. RESULTS: The incidence of preoperative pain in both anemic and non-anemic patients was 80%. The total incidence of post-operative pain was recorded as 71.7% (82.2% in anemic and 61.1% in non-anemic women). Compared with the pretreatment pain incidence and intensity, the values increased in 24 h but declined in 48 h and 72 h after treatment. Considering the posttreatment pain intensity, the mean values were higher in the three time intervals (24, 48, and 72 h) in anemic patients. Pulpal and periapical status, in contrast to age and tooth type, significantly contributed to the intensity of posttreatment pain. CONCLUSION: Regarding the importance of pain phenomenon in human life, it is recommended to consider anemia as an important risk factor for post-endodontic pain. Early diagnosis and analgesic treatment interventions in anemic females, alongside the pain control during root canal treatment, could promote the patient's satisfaction and quality of care.

Surface Microstructure of Two Bioceramics: Calcium-Enriched Mixture and Cold Ceramic in Setting Environments with Different pH Values.

Introduction: The pH of the setting environment could alter the surface characteristics of bioceramics. The present study aimed to assess the surface microstructure of calcium-enriched mixture (CEM cement) and cold ceramic (CC) in setting environments with different pH values. Materials and Methods: 12 dentin blocks with 3 mm height and internal diameter were prepared. CEM cement and CC were prepared and packed into the blocks. Samples in each bioceramics group (n = 6) were divided into 3 subgroups (n = 2) and exposed to acid, pH of 7.4, and alkaline pH for 1 week. Specimens were prepared for evaluation under a scanning electron microscope using backscattered electron (BSE) detectors. Monitoring of pH changes was rendered with a pH meter through the setting process. Results: BSE detection in an acidic environment showed more amorphous microstructures in CC specimens in comparison to CEM cement. In pH of 7.4 and alkaline pH, more unhydrated structures were observed in CEM cement compared with CC samples. During the first 48 h of the setting process, the pH changes of setting environments were more rapid in the CEM cement group in comparison to CC samples. Conclusion: pH changes during the setting process of cement could affect the surface microstructure and physical properties. In acidic environments, the crystallization of CC cement is more disrupted than that of CEM cement.

Assessment of Clinical Reasoning and Diagnostic Thinking among Dental Students.

Introduction: This study aimed to investigate dental students' clinical reasoning and diagnostic thinking ability by key feature test and "diagnostic thinking inventory" questionnaire. Methods: The present study was a descriptive cross-sectional study. The participants consisted of 61 senior dental students. Clinical reasoning and diagnostic thinking were assessed by key feature tests and the "diagnostic thinking inventory" "DTI" questionnaire, respectively. The "diagnostic thinking inventory" was developed by Bordage et al. in France and consisted of 41 questions on a 6-point Likert scale. The satisfaction of students was assessed through a 10-item questionnaire. Data were analyzed using SPSS 19 with descriptive tests (mean, SD, and percentage), student independent T-test, and Pearson correlation. The significance level was determined at p < 0.05. Results: The mean scores of the key feature test were 56.55 ± 7.80. Diagnostic thinking scores of learners were reported in diagnostic thinking 136.47 ± 16.45, flexibility in thinking 72.22 ± 11.15, and structure of memory 64.24 ± 7.84. The difference in students' scores in flexibility in thinking was significantly higher among male students than female students. (p-value = 0.04). The students' satisfaction scores were 3.53 ± 0.52, which showed relative satisfaction. Conclusion: The participants' clinical reasoning and diagnostic thinking skills were reported at a low level. This issue emphasizes the need for training to enhance diagnostic thinking and clinical reasoning in dental education. Formative evaluation and reform of the educational programs of this course should be considered.

Comparison of the Response to Pulpal Sensibility Tests in Well-Controlled and Uncontrolled Type II Diabetes Mellitus Patients: A Cross-Sectional Study.

Introduction: Diabetes mellitus is a metabolic disorder in which impairment of sensory fibers would be anticipated. The present study would assess the dental pulp response to cold and EPT sensibility tests in patients with type 2 diabetes, both well-controlled and uncontrolled. Materials and Methods: One hundred two maxillary central incisors, belonging to participants aged 35-67 years, were included in this survey. At last, 51 diabetic patients were allocated to each group of well-controlled (HbA1C < 7) and uncontrolled (HbA1C ≥ 7). Electric and cold pulpal vitality tests were conducted for all teeth. Statistical analysis was performed with Student's t-test, the chi-square test, and the multiple linear regression model. A P value less than 0.05 was considered significant. Results: Based on the results of this study, the mean value of response to EPT was 4.51 ± 2.06 and 4.41 ± 1.85 in well-controlled and uncontrolled diabetic patients, respectively. Also, the pulpal responses to cold and EPT tests had no significant differences between the two groups (P > 0.05). Conclusion: Tooth responses to the cold and EPT sensibility tests were not different in well-controlled and uncontrolled diabetic patients. Despite no statistically significant correlation, male diabetic patients in the uncontrolled group showed a lower sensory response threshold to EPT compared to a well-controlled group.

Evaluation of the Response to Pulpal Sensibility Tests (Cold, EPT) in Anemic and Healthy Women.

Introduction: The prevalence of anemia has been reported high in the female population in Iran. Anemia can be asymptomatic or can present in a variety of symptoms, especially when serum Hb values decrease. The present study would assess dental pulp response to cold and EPT sensibility tests in anemic and healthy women. Materials and Methods: One hundred twenty maxillary central incisors belonging to participants aged 18-58 years were included in this survey. 60 patients had anemia (Hb ≤ 12.5) with/without medication (30 in each group) and 60 women as controls had no anemia (Hb > 12.5) with/without medication (30 in each group). Electric and cold pulpal sensibility tests were performed for all teeth. Statistical analysis was performed with t-student, Chi-square test, and two-way ANOVA. The significance level was set as p < 0.05. Results: According to the results of this study, the mean value of hemoglobin in anemic and healthy women was 11.5 and 14.08 g/dl, respectively. The mean value of response to EPT in anemic women with and without medication was 3.21 and 3.14, respectively. The mean value of response to EPT in healthy women with and without medication was 3.81 and 3.58 g/dl, respectively. The mean value of time delay response to cold test was 3.03 and 2.82 s in anemic patients with/without medication. Also, the mean value of time delay response to cold test was 2.80 and 2.93 s in healthy women with/without medication. The pulpal responses to EPT tests had significant differences between anemic and healthy women (p=0.043). There were no significant differences between anemic and healthy women considering time delay response to the cold test (p=0.077). Conclusion: Based on the results of the present study, tooth response to the EPT sensibility test may alter in anemic patients despite medication. The evidence from this preliminary study suggests that peripheral neuropathy in anemic patients could affect pulpal sensibility tests.

Three-dimensional Pattern of Inflammatory Periapical Lesion Extension in the Premolar's Region: An Application of K-means Clustering.

BACKGROUND: Cone-Beam Computed Tomography (CBCT) provides a better diagnosis of endodontic lesions. INTRODUCTION: The present study would assess the pattern of periapical lesion extension in premolar teeth using CBCT. METHODS: In this descriptive study' 330 roots in the regions of maxillary and mandibular premolars have been evaluated. Maximum periapical lesion extensions in the three orthogonal planes (axial, coronal, and sagittal) were measured and recorded in millimeters. Measurements were compared based on gender' dental arch, tooth type, and root. Statistical analysis was performed using repeated measure ANOVA, Bonferroni, Chi-square tests, and clustering data analysis (K-means method). The significant level was set at 0.05. RESULTS: There were significant differences between the lesion expansions in the three-dimensional planes (p-value<0.001). The highest average of lesion extension in the premolar regions of the examined population was reported in the vertical dimension (4.1± 1.3), followed by horizontal buccolingual dimension (3.4±1.1) and horizontal mesiodistal dimension (3.1±1.0), respectively. According to independent variables, in the premolar region, only tooth roots showed significant differences in the lesion extension (p-value=0.002). Clustering data analysis showed that the majority of the participants were categorized in a cluster with lower lesion extension. Based on clustering data analysis, the small lesions were significantly observed in the first premolar and buccal roots. CONCLUSION: Since the periapical lesion extension in the buccolingual dimension, which could not be detected in the 2-D imaging techniques, was rather high in the region of premolar teeth, and CBCT, as a 3-D imaging technique, is a suitable option for the precise evaluation of periapical lesion extension. Also, the majority of the lesions in this tooth area are small and located in the buccal roots.

Chemical composition and antibacterial activity of Berberis vulgaris (barberry) against bacteria associated with caries.

OBJECTIVES: The aim of this in-vitro study was to determine the antimicrobial capacity of a Berberis vulgaris plant extract on the bacteria being associated with caries including, Streptococcus mutans, S. sobrinus, S. sanguinis, S. salivaris and Lactobacillus rhamnosus. MATERIAL AND METHODS: Chlorhexidine 2% (CHX) mouthwash and ampicillin (10 µg/disk) were applied as positive control groups. Inhibition zone, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) related to stem, leaf and fruit of B. vulgaris plant were recorded for every five bacteria. Data were analyzed using SPSS ver. 22, one-way ANOVA repeated measure and post hoc Tukey statistical test. The significance level was set at p < 0.05. RESULTS: There were no significant differences between the antimicrobial capacity of the positive controls and the extract from the stem and fruit of B. vulgaris (p > 0.05). The MIC values of the extract from the stem were significantly lower against S. sobrinus (64 µg/ml) and L. rhamnosus (128 µg/ml). The MIC value of the extract against S. mutans was significantly lower in the fruit group (64 µg/mL). The MBC value of the extract against S. sobrinus and L. rhamnosus was significantly lower in the stem group (128 µg/ml). The MBC value against S. mutans was significantly lower in the fruit group (128 µg/ml). CONCLUSIONS: The results showed that CHX and B. vulgaris plant extract have similar antimicrobial activity against bacteria being associated with caries. Therefore, B. vulgaris, which shows antibacterial capacity, could be considered for further investigation as a safe, phytotherapeutic mouthwash to prevent dental caries.

Assessment of dental residents' professionalism through Professionalism Mini-Evaluation Exercise (P-MEX).

PURPOSE/OBJECTIVES: The aim of the study was to assess the professional behavior of dental residents through Professionalism Mini-Evaluation Exercise (P-MEX). METHODS: This was a descriptive-analytical study. Content validity of P-MEX form was investigated for use in the context of dentistry. A total of 24-item version of P-MEX consisted of doctor-patient relationship skills (n = 7), reflective skills (n = 5), time management (n = 3), and interprofessional relationship skills (n = 9) was used in the present study. Residents in different dental specialties (n = 56) were evaluated by trained raters (448 times). Data were analyzed by descriptive (mean, SD) and analytical tests (Pearson, ANOVA, and post hoc test (Bonferroni)). RESULTS: Validity of P-MEX was approved in the field of dentistry. The mean score of professional behavior in residents were reported 2.79 ± 0.24, with minimum and maximum scores of 2.17 and 3.62, respectively. The residents' professional behavior in the domain of reflective skills and doctor-patient relationship skills were lower than the other domains. CONCLUSION(S): The results showed that the scores of professional behavior among dental residents were classified in the below expectation level and their scores have followed a downward trend from the second year. Therefore, planning for training and continuous assessment of professional behavior among residents in the faculty of dentistry should be considered.

Computational Intelligence Techniques for Assessing Anthropometric Indices Changes in Female Athletes.

BACKGROUND: Physical characteristics including body size and configuration, are considered as one of the key influences on the optimum performance in athletes. Despite several analyzing methods for modeling the slimming estimation in terms of reduction in anthropometric indices, there are still weaknesses of these models such as being very demanding including time taken for analysis and accuracy. OBJECTIVES: This research proposes a novel approach for determining the slimming effect of a herbal composition as a natural medicine for weight loss. METHODS: To build an effective prediction model, a modern hybrid approach, merging adaptivenetwork- based fuzzy inference system and particle swarm optimization (ANFIS-PSO) was constructed for prediction of changes in anthropometric indices including waist circumference, waist to hip ratio, thigh circumference and mid-upper arm circumference, on female athletes after consumption of caraway extract during ninety days clinical trial. RESULTS: The outcomes showed that caraway extract intake was effective on lowering all anthropometric indices in female athletes after ninety days trial. The results of analysis by ANFIS-PSO was more accurate compared to SPSS. Also, the efficiency of the proposed approach was confirmed using the existing data. CONCLUSION: It is concluded that a development in predictive accuracy and simplification capability could be attained by hybrid adaptive neuro-fuzzy techniques as modern approaches in detecting changes in body characteristics. These developed techniques could be more useful and valid than other conventional analytical methods for clinical applications.

Pattern of Endodontic Periapical Lesion Extension in Anterior Teeth: A CBCT Study in an Iranian Population.

Introduction: Health of periapical tissues has been considered as an index for the evaluation of endodontic outcomes. The present study sought to assess the pattern of periapical lesion extension in anterior teeth using cone-beam computed tomography (CBCT). Methods and Materials: In this descriptive study' 199 CBCT images belonged to patients aging from 15 to 79 were assessed according to periapical lesion extension in the regions of maxillary and mandibular anterior teeth. Maximum periapical lesion extensions in three orthogonal planes were measured and recorded in millimeters and were assessed according to age' gender' dental arch and tooth type. Statistical analysis was performed using percentages' repeated measure ANOVA and Bonferroni tests. The significant level was set at 0.05. Results: The highest average of lesion extension, in both maxilla and mandible, was in vertical dimension' followed by horizontal buccolingual and horizontal mesiodistal dimensions' respectively. There were significant differences between the vertical and mesiodistal (P=0.004) and also mesiodistal and buccolingual (P=0.010) periapical lesion extension dimensions. In addition, there were significant differences in maxilla and mandible (P=0.012). In maxilla, there were no significant differences between the three tooth types (P=0.346) but in the mandibular arch, there were significant differences between central-canine (P=0.004) and lateral-canine (P=0.026). According to independent variables, only gender had a significant effect on the lesion extension in anterior regions of maxilla and mandible (P=0.001). The periapical lesion extensions were significantly higher in men compared with women. Conclusions: The bone destruction_as a consequence of periapical inflammatory process_ was greatest in the vertical, and lowest in the horizontal mesiodistal dimensions. That way, the extension in buccolingual dimension, which could not be detected in the 2-D imaging techniques, was rather high in the present study. Thus CBCT, as a 3-D imaging technique, could be recommended for the precise evaluation of lesion extension in the periapical area.

Evaluation of Microhardness of Mineral Trioxide Aggregate After Immediate Placement of Different Coronal Restorations: An In Vitro Study.

OBJECTIVES: The purpose of this research was to evaluate the effect of immediate placement of different restorative materials in comparison with a temporary restoration on the surface microhardness of mineral trioxide aggregate (MTA). MATERIALS AND METHODS: Access cavities were prepared in 40 extracted human molars, and a 3-mm layer of MTA was placed in the pulp chamber. The samples were divided into eight groups (n=5). Ten minutes after the MTA placement, two groups were restored with Zonalin temporary restoration, while the other six groups were restored with glass-ionomer cement (GIC), resin-modified glass-ionomer (RMGI), or resin-based composite. In each group, the Vickers microhardness (VMH) of MTA was determined after 7 and 21 days. Data were entered into SPSS 17 software program and were analyzed by two-way analysis of variance (ANOVA). The significance level was set at 5%. RESULTS: The type of restorative materials had a statistically significant effect on the microhardness of MTA (P=0.002). However, the microhardness of MTA was neither significantly influenced by the timing of final restoration (P=0.246) nor by the time-material interaction (P=0.116). CONCLUSIONS: Based on the results of the present study and by considering the limitations of laboratory studies, it is recommended to postpone the placement of final restorations until the underlying MTA is completely set. Otherwise, in the clinical conditions in which early covering of MTA is recommended, sufficient moist-curing and hydration should be guaranteed by selecting a restorative material with the lowest hydrophilic interaction energy.

Effects of a Peganum harmala (Zygophyllaceae) preparation for root canal disinfection.

The aim of this study was to determine the antimicrobial capacity, minimum inhibitory concentration (MIC), and cytotoxic effects of a Peganum harmala seed extract in comparison to 5.25% sodium hypochlorite (NaOCl). The oral pathogen Enterococcus faecalis was used to evaluate the antimicrobial capacity, and the MIC values were determined through serial dilution. Inhibition zones were measured in millimeter, and the data were analyzed statistically by analysis of variance and the Tukey HSD test. For cytotoxicity testing, P. harmala seed extract and 5.25% NaOCl solution were incubated with L929 fibroblast cells. After 1, 24, and 72 hr of incubation, cells were stained and the optical density determined with an enzyme-linked immunosorbent assay (ELISA) reader. Data were analyzed with Chi-Square statistical test. The significance level was set at p < .05. There was no significant difference between the antimicrobial capacity of 5.25% NaOCl and the P. harmala extract (p > .05; MIC 4 µg/ml). The Microculture Tetrazolium (MTT) assay test showed that the cytotoxic effects of the P. harmala extract were significantly lower than 5.25% NaOCl (p < .05). The results show that 5.25% NaOCl and P. harmala seed extract have similar antimicrobial activity against Enterococcus faecalis; but P. harmala, which shows reduced cytotoxicity, should be considered for further investigation as a safe, phytotherapeutic, intracanal irrigant.

Influence of Immediate Coronal Restoration on Microhardness of CEM Cement: An In Vitro Study.

Introduction: Coronal restoration could affect the setting reaction of the underlying CEM cement. The aim of the present study was to evaluate the effect of immediate coronal restoration placement on the subsurface microhardness of CEM cement. Methods and Materials: In 50 extracted human mandibular molars, access cavities were prepared and CEM cement was placed in the pulp chamber at a 3-mm thickness. Samples were divided into ten groups (n=5). CEM cement was placed and after 10 min, two groups were restored with Zonalin temporary restoration and eight groups were restored with glass ionomer cement (GIC), resin modified glass ionomer (RMGI), resin based composite and amalgam respectively. Vickers microhardness number (VHN) of CEM cement was measured in two time intervals (7- and 21-days). Data was analyzed with SPSS and two-way analysis of variance and Bonferroni tests. Level of significance was set at the 5%. Results: The mean VHN of CEM cement showed statistically significant differences only between Zonalin and amalgam groups (P=0.021). There were also significant differences considering the effect of time (P=0.042) and material (P=0.046). Although the effect of time-material on the microhardness values showed no statistically significant differences (P=0.636). Conclusion: Based on the results of the present study, immediate placement of final restorations affects the setting reaction in underlying CEM cement. Therefore, sufficient moist curing and hydration should be guaranteed before placement of the coronal restoration.

Concurrent Effects of Bleaching Materials and the Size of Root Canal Preparation on Cervical Dentin Microhardness.

INTRODUCTION: The aim of the present study was to evaluate the concurrent effect of root canal preparation size and intra coronal bleaching on dentin microhardness. METHODS AND MATERIALS: Seventy-two intact anterior teeth were root canal treated and randomly divided into two groups (n=36) according to the size of coronal root canal preparation. The coronal portions of the canals were then enlarged with #2 and 4 Peeso reamers, respectively. Following root canal obturation, teeth were assigned into three groups (n=12) to be treated with bleaching agents containing 35% hydrogen peroxide (HP), sodium perborate (SP) and distilled water as control group. The teeth were stored at 37ºC and 100% humidity for 7 days. Dentinal blocks with 3 mm thickness were obtained from the cervical region and Vickers microhardness number (VHN) were measured for outer and inner dentin in each tooth sample. Data were analyzed using two-way ANOVA and Tukey's HSD tests. RESULTS: In the outer dentin, the mean VHN in the HP and control groups showed statistically significant differences (P=0.047). The mean VHN of inner dentin for the large preparation size was statistically higher in comparison to the small preparation size (P=0.042). There was a statistically significant difference in the mean VHN of inner dentin with small preparation size between HP and SP groups (P=0.029) and HP and control groups (P=0.021). CONCLUSION: Intra coronal bleaching with 35% hydrogen peroxide, affects the inner and outer dentin significantly. Excessive removal of cervical dentin, following root canal preparation, alongside the adverse effect of bleaching materials on dentin could result in the tooth fracture.

Evaluation of the Course of the Inferior Alveolar Canal: The First CBCT Study in an Iranian Population.

BACKROUND: The frequent anatomical variations of the inferior alveolar nerve (IAN) course should be considered prior to any treatment in this area. The aim of this study was to evaluate the course of the inferior alveolar canal (IAC) as it appears in the archived CBCT images of the mandible. MATERIAL/METHOD: This cross- sectional study evaluated a sample of 156 CBCT examinations. The pattern of the IAC was evaluated and the prevalence of different patterns according to age and gender were recorded. In order to find the frequency of mandibular canal type among different ages, the patients were put into the three age groups (20-29, 30-44 and 45-59).The data were analyzed using Chi-square test and the significance level was set as p≤.05. RESULTS: Out of 156 patients, 52 canals was straight type, 52 had Catenary type and 52 of them were presented with Progressive descending type. There was not statistically significant difference between two genders (Pv=0.092). According to the type of the IAC course, there was a not statistically significant difference between the three age groups (Pv=0.32). CONCLUSIONS: Cone beam computed tomography is a useful method for precise assessment of the IAC course.

Evaluation by CBCT of Root and Canal Morphology in Mandibular Premolars in an Iranian Population.

OBJECTIVE: To compare the root canal morphology in the left and right mandibular premolars on cone beam computed tomography (CBCT) images. METHODS: In this analytical cross-sectional study, 457 CBCT images, including human left and right mandibular premolars were evaluated. CBCT scans were investigated in the three spatial planes and differences in the number of roots and canals were recorded. Data were analysed using chi-square test. The significance level was set at P < 0.05. RESULTS: From 914 mandibular first premolars, in the left side, 85.6% had one root and 14.4% had two roots; 69.6% had one canal and 30.4% had two canals. In the right side 87.3% had one root and 12.7% had two roots; 66.5% had one canal and 33.5% had two canals. There was no statistically significant difference in the number of roots (P = 0.440) and canals (P = 0.321) between left and right mandibular first premolars. From 914 mandibular second premolars, in the left side, 94.3% had one root and 5.7% had two roots; 77.9% had one canal and 22.1% had two canals. In the right side, 95.6% had one root and 4.4% had two roots; 83.4% had one canal and 16.6% had two canals. There was a significant difference in the number of canals between the left and right mandibular second premolars (P = 0.036). CONCLUSIONS: The root canal morphology in the mandibular left and right premolars was different, but there was a significant difference only in the number of canals in the mandibular second premolars.

Gender difference and root canal morphology in mandibular premolars: A cone-beam computed tomography study in an Iranian population.

BACKGROUND: Mandibular premolars are of the most difficult teeth to treat endodontically. AIMS: To compare the root canal morphology of mandibular premolars between two genders in an Iranian population. SETTINGS AND DESIGN: Totally, 230 cone-beam computed tomography images of the mandibles belonged to 115 males and 115 females were evaluated in the three spatial planes. MATERIALS AND METHODS: The total number of roots and canals in the mandibular premolars was counted, and the difference between males and females were analyzed. STATISTICAL ANALYSIS: Data were analyzed using Chi-square test. The significance level was set as P < 0.05. RESULTS: The majority of mandibular first and second premolars had one root (85.7% and 94.8%, respectively) and one canal (63.9% and 78.3%, respectively). The number of roots in the mandibular first premolars had statistically significant difference between two genders (P = 0.001). There was no significant difference between two genders in the number of roots (P = 0.208) and canals (P = 0.498) in the mandibular second premolars. CONCLUSION: According to the results of this study, the root canal morphology in the mandibular first premolars had statistically significant difference between two genders.

Lack of correlation between microbial penetration method and electro chemical technique for assessment of leakage through the root canal fillings.

AIMS: The purpose of this study was to compare microbial penetration method and electrochemical technique for evaluation of the apical seal. MATERIALS AND METHODS: A total of 28 teeth were prepared using the step-back technique to ISO size 40 master apical files. The specimens were randomly divided into an experimental group, two positive and two negative controls. Root canals in the experimental and negative control group were filled with gutta-percha (GP) and sealer, using lateral condensation technique. In the positive control group, canals were filled with GP without any sealer. The external surface of each tooth was coated with two layers of the nail varnish, except for the access opening and the apical foramen. In the negative control group, the teeth were completely covered with nail varnish. The apical seal was recorded with two methods, each successively used on the same teeth: An electrochemical method and a bacterial penetration method. STATISTICAL ANALYSIS USED: The correlation of the electro chemical readings with the results obtained from bacterial micro leakage test was evaluated by Pearson's correlation coefficient. RESULTS: Correlation coefficient of the measurements obtained from the two evaluation methods, was 0.23 (r = 0.23), so the correlation was not statistically significant (P = 0.275). CONCLUSIONS: This study shows that several studies by different methods are necessary before evaluation of the marginal leakage.

Impact of root canal preparation size and taper on coronal-apical micro-leakage using glucose penetration method.

OBJECTIVES: The purpose of this in vitro study was to assess the effect of root canal preparation size and taper on the amounts of glucose penetration. MATERIAL AND METHODS: For conducting this experimental study, eighty mandibular premolars with single straight canals were divided randomly into 2 experimental groups of 30 samples each and 2 control groups. Using K-files and the balance force technique, canals in group 1 were prepared apically to size 25 and coronally to size 2 Peesoreamer. Group 2 were instrumented apically and coronally to size 40 and size 6 Peesoreamer, respectively. Rotary instrumentation was accomplished in group 1; using size 25 and .04 tapered and in group 2, size 35 and .06 tapered Flex Master files. Canals were then obturated by lateral compaction of cold gutta-percha. Glucose penetration through root canal fillings was measured at 1, 8, 15, 22 and 30 days. Data were recorded as mmol/L and statistically analyzed with Mann-Whitney U test (P value=. 05). RESULTS: In comparison to group 1, group 2 showed significant glucose leakage during the experimental period (P value < .0001). Also, in each experimental group, the amount of micro-leakage was significantly increased at the end of the study. CONCLUSIONS: Under the condition of this study, the amounts of micro-leakage through root canal fillings are directly related to the size and taper of root canal preparation and reducing the preparation size may lead to less micro-leakage. Key words:Dental leakage, root canal preparation, endodontics.