Clinical and Radiographic Failure of Non-surgical Endodontic Treatment and Retreatment Using Single-cone Technique with Calcium Silicate-Based Sealers: A Systematic Review and Meta-Analysis.

INTRODUCTION: This systematic review and meta-analysis aimed to evaluate the clinical and radiographic failure of non-surgical endodontic treatment and retreatment for mature permanent teeth with or without apical periodontitis using the single-cone (SC) obturation technique with calcium silicate-based bio-ceramic (CSBC) sealers and to compare these failure rates to other sealer materials and obturation techniques. METHODS: A comprehensive search was conducted using MEDLINE (PubMed), Embase, Cochrane Library, Scopus, Web of Science, and gray literature up to March 2023. Two reviewers assessed the eligibility of the included studies. Eligible studies were critically appraised for risk of bias and quality of evidence. Subsequently, a meta-analysis of pooled data was conducted utilizing the RevMan software (P< 0.05) to evaluate the failure rate of non-surgical root canal therapy using CSBC sealers and SC obturation procedures. Separately, another analysis was conducted to compare those results with the outcome of non-surgical root canal therapy using alternative obturation materials and methods. RESULTS: 5 studies were included. The pooled failure rate for non-surgical endodontic treatment and retreatment combined using CSBC sealers and SC obturation technique was 6.8% [95% confidence interval (CI)= (3%-12%), I2 = 46%]. A second analysis was conducted on the three included clinical trials to compare the outcomes of the intervention (CSBC sealers and SC obturation technique) and control groups (other sealers and other obturation techniques). This analysis found no significant difference between the two groups regarding clinical and radiographic failure of endodontic treatment and retreatment [Risk ratio=0.71, 95% CI = (0.33,1.51), I2 = 0]. This difference was also not statistically significant when the failure rate of primary root canal treatment and retreatment were separately analyzed [Combined Risk ratio of primary root canal treatment=0.94, 95% CI = (0.46,1.93), I2= 0%; Combined Risk ratio of retreatment=0.21, 95% CI = (0.001, 75.46), I2= 0%]. CONCLUSIONS: The overall results of this systematic review and meta-analysis demonstrate that the SC obturation technique with CSBC sealer provides similar results compared to other obturation materials and techniques in facilitating the healing of apical periodontitis.

Comparative Outcomes of Pulpotomy in Mature Molars with Irreversible Pulpitis: A Non-Randomized Trial Evaluating Calcified and Non-Calcified Pulp Chambers.

Introduction: This non-randomized clinical trial investigated the outcomes of full pulpotomy in adult molars with irreversible pulpitis, comparing those with calcified and non-calcified pulp chambers over 6 and 12 months. Materials and Methods: A total of 101 adult permanent molars with irreversible pulpitis, in individuals over 12 years old, were categorized based on pulp chamber calcification observed in radiographic images by two endodontists. Subsequently, full pulpotomy procedures were performed, achieving hemostasis, and applying a 2 mm layer of calcium-enriched mixture (CEM) cement as a pulp covering agent. After 48 hours, the setting of the CEM cement was verified, followed by the application of a layer of resin-modified glass-ionomer. The tooth was then restored using amalgam. Clinical and radiographic evaluations were conducted at 6-month and 1-year follow-ups by blinded endodontists. Success rates were compared using Fisher's exact test and logistic regression tests with a significance level of 0.05. Results: Among the 97 patients with 6-month and 1-year follow-ups, all achieved clinical success. Radiographic success rates were 99% at 6 months and 96.9% at 1 year, regardless of pulp calcification. In the 6-month follow-up, success rates were 98.07% for non-calcified pulp chambers and 100% for calcified pulp chambers. At the 1-year follow-up, success rates were 96.1% and 97.8%, respectively. Statistical analysis showed no significant difference in radiographic success rate between the two groups at both follow-ups (P>0.05). Conclusions: Full pulpotomy using CEM cement is a successful treatment for adult permanent teeth with calcified and non-calcified pulp chambers presenting signs and symptoms of irreversible pulpitis up to a 1-year follow-up. This study provides compelling evidence that vital pulp therapy can be effectively employed in the pulpotomy of calcified teeth, at least in the short term.

Niosomal Doxycycline and Triamcinolone: A Novel Approach to Minimize Cytotoxicity in Endodontic Medicaments.

Introduction: Mechanical root canal preparations and irrigation solutions are essential for reducing microbial counts in the root canal system. However, these methods do not completely eliminate microorganisms. Intracanal medicaments are used to further decrease microbial counts. This study aims to assess the cytotoxicity of various intracanal medicaments. Materials and methods: In this in vitro study, murine fibroblast cell lines (L929) were cultured in a controlled environment. The MTT assay was employed to evaluate the cytotoxicity of different medicament combinations, including calcium hydroxide and triamcinolone (D1), niosomal doxycycline and triamcinolone (D2), calcium hydroxide (D3), and a combination of doxycycline and triamcinolone (D4). Statistical analysis was performed using ANOVA and Dunnett's test. Results: The results indicated that D1 and D2 had lower cytotoxicity, while D4 exhibited the highest cytotoxicity. D1 was found to be non-cytotoxic up to a concentration of 500 µg/mL over a period of 72 hours. D2 and D3 showed similar effects up to concentrations of 250 µg/mL and 100 µg/mL, respectively, for 72 hours. In contrast, D4 exhibited cytotoxicity at concentrations above 75 µg/mL at 72 hours. Conclusion: This study suggests that encapsulating doxycycline in niosomal structures (D2) reduces cytotoxicity in murine fibroblast cell lines (L929) for at least 24 and 48 hours. These findings offer promising implications for the development of endodontic medicaments with improved biocompatibility.

Comparative Efficacy of Analgesics for Pain Relief in Patients with Symptomatic Irreversible Pulpitis Prior to Emergency Endodontic Treatment: A Randomized Controlled Trial.

Introduction: This study aimed to compare the efficacy of ibuprofen, Novafen, mefenamic acid (MA), and celecoxib for pain relief in patients with symptomatic irreversible pulpitis prior to emergency endodontic treatment. Materials and Methods: This clinical trial was conducted on 120 patients with moderate to severe pain due to symptomatic irreversible pulpitis seeking emergency endodontic treatment. The patients were randomly divided into 4 groups to receive Novafen, MA, Celecoxib, and ibuprofen. The pain score of patients was measured before and 1 hour after analgesic intake using a visual analog scale (VAS). The success of analgesic treatment was analyzed by the binary logistic regression model. Results: A total of 117 patients including 76 females and 41 males with a mean age of 30.29 years completed the study and were statistically analyzed. Ibuprofen had the highest analgesic efficacy followed by Novafen, and caused a significantly greater reduction in pain score compared with MA and celecoxib [OR (Ibuprofen vs MA)=1.28, OR (Ibuprofen vs Celecoxib)=3.74, OR (Novafen vs MA)=2.94, OR (Novafen vs Celecoxib)=2.94, P<0.05]. Ibuprofen and Novafen had no significant difference in analgesic efficacy (P>0.05). Baseline pain score was a predictive factor for the success of analgesics (P<0.05). The success of analgesic treatment decreased by 0.68 times with each unit increase in pain score (P<0.05). Gender and age of patients had no significant effect on success of analgesics (P>0.05). Conclusion: Both ibuprofen and Novafen can serve as the analgesics of choice for pain relief in patients with symptomatic irreversible pulpitis with moderate to severe pain when emergency endodontic treatment cannot be immediately performed.

Comparison of Oral Health-Related Quality of Life in Partial and Complete Denture Wearers: A Propensity Score Analysis.

Background: Dentures, both partial and complete, have been shown to have the same impact on one's quality of life. Due to the impossibility of randomization in these studies, they are prone to selection bias. This study aimed to compare the effect of partial and complete dentures on oral health-related quality of life (OHRQoL) by propensity score to overcome selection bias. Methods: This is a cross-sectional descriptive-analytic study. A total of 1376 people participated in this study. Age, sex, marital status, education level, smoking, smoking opium and its derivatives, and dental visit was collected by a checklist. OHRQoL was measured by the OHIP-14 questionnaire. The generalized boosted model was used to estimate the propensity score. Missing data were imputed using multiple imputations with mixed models. The assumptions of multivariable regression analysis and propensity score method were first examined, and then the quality of life related to oral health was compared between the two groups. Results: The regression model's assumptions were not verified due to high skewness and collinearity. The results of the normality test (P < 0.001) and goodness fit test (P < 0.001) revealed that the regression model did not fit the data. The propensity score method reduced at least 76% of the bias resulting from the distribution difference between the confounding variables and was used for analysis. In the regression and propensity score method, the results showed that the total OHIP-14 score of the complete prosthesis group was higher than the partial prosthesis group at 3.92 (95% CI = (2.18,5.65)) and 3.64 (95% CI = (1.93,4.53)), respectively. This difference was clinically and statistically significant (P < 0.001). In addition, there is a significant difference in the two groups based on propensity in all seven areas (P < 0.001). But there is no significant difference in the regression adjustment of the Functional limitation of the two groups (P = 0.035). Conclusion: The propensity score has fewer assumptions than the regression method and may be more reliable for OHIP scores. The propensity score analysis revealed that despite the costs and repair issues associated with partial dentures, complete denture wearers have lower OHRQoL than partial denture wearers.

Does ultrasonic activation of irrigation during endodontic therapy improve the clinical and microbiological effects?

Data sources A comprehensive collection of databases were searched from inception to August 2020, such as Cochrane, MEDLINE, Scopus and Web of science. Also, references and citations of retrieved records, conference proceedings and leading journals were searched.Study selection All randomised clinical trials on root-canal-treated adult permanent teeth that compared the outcomes of ultrasonically activated irrigation (UAI) to syringe irrigation (SI) were eligible. The outcomes considered were post-operative pain, pain intensity, periapical healing after 12 months, the incidence of microbial presence, microbial quantification, lipopolysaccharides (LPS) quantification and lipoteichoic acid quantification. Studies with insufficient data for risk of bias assessment or other outcomes were excluded.Data extraction and synthesis The two independent reviewers did the screening process in title, abstract and full-text assessment steps. Also, the data extraction process and risk of bias assessment were done by two independent reviewers. Any disagreement was resolved by consensus or the opinion of a third reviewer. Any missing information was filled in by contacting the authors. The Cochrane risk-of-bias tool for randomised trials was used to assess the risk of bias. The following domains were evaluated for risk of bias: randomisation process, deviation from the intended interventions, missing outcome data, outcome measurement and the selection of the reported results. If all domains were rated as 'low risk', judgements would be rated as 'low risk', otherwise, 'high risk'. The risk ratios and mean risk difference with 95% confidence interval (CI) were used as measure effect. The random effects model was used to combine the effects. The heterogeneity is measured by I2 test (I2 test >50% and p <0.1 considered as substantial heterogeneity). The level of certainty of evidence for clinically important outcomes was determined using the guidelines of Grading of Recommendations Assessment, Development and Evaluation working group.Results Four studies entered the meta-analysis stage based on pain outcomes. The overall risk of bias for three of them was assessed as high. All of them had examined pain incidence before 24 hours but only two studies have examined the occurrence of pain in the period of 24-72 hours and after 72 hours to 7 days. Considerable heterogeny was among the incidence of pain <24 hours between studies (I2= 83%). Therefore, the incidence of pain in two sub-groups of vital and non-vital pulp has been investigated. In the non-vital pulps, the incidence of pain by UAI was half of the incidence of SI pain (relative risk= 0.50; 95% CI 0.35-0.71; I2 = 0%; 308 teeth). But no significant difference was seen in vital pulps. Also, there was no significant difference in the occurrence of pain after 72 hours between the two methods. Two studies assessed the intensity of pain in three periods: <24 hours, 72-24 hours, more than 72 hours and less than 7 days. The combined results based on vital and non-vital groups resulted in no significant difference in any period. Pooled data of pain outcomes were assessed with very low or low confidence of evidence.Five studies with microbiology-related outcomes entered the final analysis stage. The overall risk of bias for two of them was high. Three studies evaluated the effect of the irrigation method on microbial presence as an outcome. High heterogeneity was among the results of the studies (I2= 72%). However, with and without subgroup analysis, meta-analysis results showed no significant difference between these two methods. A lower microbial count was found with UAI than SI in a meta-analysis of four studies (standardised mean difference-pooled - 0.40; 95% CI [-0.78, -0.02]; I2 = 0%; 126 teeth). Two studies measured LPs. The meta-analysis showed lower values of LPS with UAI compared to SI (34, 37) (mean difference pooled - 0.06; 95% CI [-0.11, -0.01]; 61 root canals; I2 = 29%). One study measured lipoteichoic acid and found no significant difference between the irrigation methods.Three studies with treatment-success-related outcomes entered the meta-analysis stage with an overall high risk of bias. Two studies' pooled data revealed no significant difference between the irrigation methods regarding treatment failure. One study assessed periapical-lesion volume after treatment and found no significant difference between the irrigation methods.Conclusions According to limited data, UAI may reduce the risk of post-operative pain during the first 24 hours and reduce microbial counts, particularly cultivable germs in cases of apical periodontitis. However, most meta-analyses are conducted on a small number of studies and have an overall 'very low' to 'low' certainty of evidence; as a result, the evidence is deemed insufficient to either support or disprove UAI efficacy when compared to SI.

What is the best effective postoperative medication in reducing pain after non-surgical root canal treatment?

Data sources Medline, Embase, CENTRAL, Cumulative Index to Nursing and Allied Health Literature and Scopus databases were searched (until July 31 2019). They searched the WHO International Clinical Trials Registry Platform and ClinicalTrials.gov databases for completed and ongoing trials, as well as ProQuest, Google Scholar (first 100 hits) and the OpenGrey database for those unpublished. In addition, abstracts of annual meetings from the American Association of Endodontists, the International Federation of Endodontic Associations and the European Society of Endodontics were searched. A manual search of references in related papers and textbooks was carried out. Any missing information was filled in by contacting the authors.Study selection All randomised clinical trials (RCT) of nonsurgical endodontic therapy with pharmaceutical treatments provided postoperatively to alleviate pain on adult subjects were eligible. Two reviewers selected the studies and extracted the data and the results were examined by a third reviewer. Any differences were settled with the help of a fourth reviewer.Data extraction and synthesis Two authors independently evaluated and retrieved data from chosen trials found through searches. Another reviewer looked at the trial selection and data extraction. They also assessed the risk of bias in each of the research they chose.The mean and standard deviation of a 0-100 (mm) visual analogue pain scale were extracted or derived from study text, graphs and tables The postoperative medications were compared using network meta-analysis in a Bayesian model. Mean differences (MDs) and 95% credible intervals (CrIs) of post-operative pain were estimated at 6-8 hours and 12, 24 and 48 hours. Two authors utilised the CINeMA web application to assess the confidence in the main results by accounting for six domains: within- and across-study bias; indirectness; imprecision; heterogeneity; and incoherence. Each domain was assigned no concerns, major concerns, or minor concerns. Each result would be assigned a confidence level of high, moderate, low, or very low. To establish an agreement, a third reviewer was consulted.Results From the initial search of 969 records, 11 RCTs matched the inclusion criteria. Five studies were rated as having a low risk of bias, five as having a moderate risk and one as having a high risk. Moderate and major heterogeneity and some inconsistencies were detected, though not statistically significant.Oral medications were classified into placebo, non-steroidal anti-inflammatory drugs (NSAIDs), opioids, acetaminophen, NSAIDs + acetaminophen, corticosteroids, NSAIDs + benzodiazepines and NSAIDs + opioids groups.With moderate confidence, NSAIDs + acetaminophen were shown to be more efficacious than placebo at 6-8 hours following nonsurgical root canal therapy (MD = 22; 95% CrI = [-38, -7.2]). With very low confidence, NSAIDs had a greater effect than placebo after 12 and 24 hours (MD = -28; 95% CrI = [-49, -7] and MD = -15; 95% CrI = [-27, -2.3], respectively). After 6 12 and 24 hours, other medications were no more effective than placebo in pain reduction. After 48 hours, no treatment was more effective than placebo. Subgroup analysis found that other medications, such as corticosteroids and acetaminophen, were no more beneficial than placebo for patients who could not use NSAIDs. Six trials provided safety data and concluded that the therapies were safe and posed no significant risks.Conclusions Very low to moderate-quality evidence suggests that postoperative administration of NSAIDs and acetaminophen, or NSAIDs alone, reduced discomfort after non-surgical root canal therapy in patients with irreversible pulpitis or pulpal necrosis. Trials have shown, however, that using these drugs does not result in major complications. We cannot, however, be confident that they are risk-free.

The Effect of Long Service Life on the Accuracy of Dentaport ZX Electronic Apex Locator.

Introduction: Electronic apex locators are among the most acceptable instruments for determining root canal length. The present study aimed to evaluate the effect of long service life on the accuracy of the Dentaport Root ZX (DP ZX) electronic apex locator (EAL). Materials and Methods: In this study, fifty single-rooted freshly extracted human teeth were used. After determining the root canal length with a K-file and a dental operative microscope, the canals were measured with four separate DP ZX apex locators (two with more than 6 years of life service while two others had less than 6 years of life service). Data were analyzed by repeated ANOVA measurement. Results: No significant difference was found between the EALs with different years of life services (P=0.62). All EALs could determine root canal length with high accuracy of more than 94%. Conclusion: Based on the results of this in vitro study, the long service life had no significant impact on the accuracy of DP ZX EALs in terms of root canal length determination.

Possibility of Bypassing Three Fractured Rotary NiTi Files and Its Correlation with the Degree of Root Canal Curvature and Location of the Fractured File: An In Vitro Study.

Introduction: This study aimed to evaluate the success rate of bypassing three NiTi rotary files (RaCe®, Hero 642®, and K3®), fractured in various root canal locations of extracted mandibular molars with two different canal curvatures. Materials and Methods: Ninety freshly extracted human first or second mandibular molars were selected. Three millimeters of the file tip (RaCe®, Hero 642®, and K3®), was fractured intentionally in the mesiobuccal root canal of each tooth by weakening the file in the last 3 mm of files #30 with 4% taper and preparing the root canals with two different degrees of curvature (n=30). Then, bypass possibility of the fractured files was evaluated using #8, #10, and #15 K-files and compared in different groups. In addition, the rate of accidental procedural errors was compared between these groups. Data were analyzed with univariate analysis and logistic regression models at a significance level of 0.05. Results: The overall success rate of bypassing was 61.1%. RaCe® files had the highest and the K3® files had the lowest bypass possibility rates (P=0.01); the greater the degree of canal curvature, the less successful the bypass procedure (P=0.01). The fracture of the files used to bypass was the most prevalent error. Conclusion: Based on this in vitro study the type of fractured file and the amount of canal curvature affected the success rate of the bypassing technique. In RaCe® files and the mild curvature group, the success rate was the highest.

Evaluation of the Levels of Evidence in Three Clinical Chapters in Five Editions of the Textbook Pathways of the Pulp.

Introduction: The levels of evidence (LOE) of dental education texts is critical from the educational point of view. The present study aimed to evaluate the levels of evidence of references used in three clinical chapters in the textbook Pathways of the Pulp. Material & Method: The references of three clinical chapters in the text book Pathways of the Pulp were assessed in five of its editions. The levels of evidence were ranked according to study type and the Oxford scale from 0 to 5. The chi-square test was used to compare the level of evidence between different editions of the "Retreatment," "Trauma," and "Surgery" chapters. Results: A total of 3656 references were reviewed and analyzed from the "Trauma" (928 references), "Re-treatment" (1906 references), and "Surgery" (822 references) chapters in the 1998, 2002, 2006, 2011, and 2016 editions. The percentage of the LOE 0 (no evidence) was high (>60%) in all three chapters in all editions (P<0.001). The levels of evidence had the same distribution in all editions (P=0.871). The LOE of the "Re-treatment" (P=0.044) and "Surgery" (P<0.001) chapters changed in some editions. Conclusion: The majority of references in the three clinical chapters of the book are low-level evidence. Encouragement policies for researchers to conduct studies with high LOE are necessary.

Outcomes of root canal therapy or full pulpotomy using two endodontic biomaterials in mature permanent teeth: a randomized controlled trial.

OBJECTIVE: The concept of minimally invasive endodontics recommends less-invasive vital pulp therapy (VPT) modalities over more aggressive traditional endodontic approaches in mature permanent teeth with carious pulp exposure, including irreversible pulpitis (IP) cases. Consequently, VPT needs to be compared with root canal therapy (RCT) in terms of treatment outcomes. This randomized clinical trial compares the results of full pulpotomy using two calcium-silicate cements, i.e., mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement, with RCT in mature permanent teeth. MATERIALS AND METHODS: A total of 157 carious pulp exposure cases in two academic centers with/without established IP were selected/included/randomly appointed to three study arms; (i) RCT (n = 51) as the reference treatment, (ii) pulpotomy with ProRoot MTA (PMTA; n = 55), and (iii) pulpotomy with CEM cement (PCEM; n = 51) as two alternative VPT treatments. Two-year clinical/radiographic results were the outcomes of interest. Data were statistically analyzed through the analysis of variance, chi-square, Fisher exact test, and Kruskal-Wallis. RESULTS: At 2-year recall, 147 teeth were examined (6.4% dropout). All molars, except for one, were clinically functional/symptom-free, and there was no statistical difference between the three study arms (p = 0.653). The radiographic success rates in RCT, PMTA, and PCEM arms were 98%, 100%, and 97.9%, respectively, without statistically significant differences (p = 0.544). CONCLUSION: In the management of mature permanent teeth with/without established IP, all experimental groups exhibited equivalent/comparable results. CLINICAL RELEVANCE: Simple VPT using MTA/CEM can be suggested/recommended as a viable advantageous alternative to RCT for the management of carious pulp exposures with/without sign/symptoms of IP.

Impact of Laughter Therapy on Anxiety and Pain in Pediatric Dentistry: A Double-Blinded Randomized, Controlled Clinical Trial

Abstract Objective: To evaluate the effect of laughter therapy on reducing anxiety and pain during dental procedures in children 5-7 years of age. Material and Methods: 48 children aged 5-7 years were included in this cross-over double-blinded clinical trial after the parents completed the Screen for Child Anxiety Related Disorder questionnaire (SCARED). After allocation into two groups: laughter intervention (A) and neutral intervention (B), the anxiety as well as pain were determined by Modified Child Dental Anxiety Scale Faces questionnaire (MCDASF) and the Wong-Baker Faces Scale, respectively. Also, the child's behavior during the treatment was recorded using the Sound, Eye, Motor scale (SEM). Data were analyzed by SPSS 21 using Paired t-test, Independent t-test, Chi-square, Mann-Whitney and Wilcoxon's test. Results: The mean score of anxiety in the laughter intervention group (17.42±2.74) was significantly less than (22.06±2.16) in the neutral intervention group (p=0.000) and lower in boys in both groups (p=0.000, p=0.047). The mean pain severity reported by the children in the neutral intervention group (5.33±1.81) was higher than in the laughter intervention group (2.38±1.87; p=0.00) and higher in girls in both groups (p=0.02; p=0.03). Conclusion: The laughter intervention before dental procedures had a significant effect on reducing anxiety and pain during dental treatment (AU).

Knowledge and Attitude About Research Ethics Among Iranian Dental Students

ABSTRACT Objective: To evaluate the knowledge and attitude of the students of Kerman dental school (Iran) about ethics in dental research. Material and Methods: This cross-section study was conducted on 307 dental students selected through the census sampling method. Data were collected by a researcher-made questionnaire consisting of 12 items about knowledge and 17 items about attitude toward research ethics. Data analyzed in SPSS software using t-test and linear regression test. P-values of less than 0.05 were considered statistically significant. Results: Of the respondents, 33.9% were male and 66.1% were female, and 44% had good knowledge and 20.8% had a positive attitude about research ethics. A significant correlation was found between knowledge and attitude. A significant correlation was also observed between knowledge and participation in research workshops. Knowledge and attitude showed no significant correlation with gender or year of admission. Conclusion: Participants had appropriate knowledge and attitude about research ethics. There is some room for improvement in research ethics education concerning experimental works and retrospective studies on biologic samples. Holding research workshops with an introduction to ethical codes of research is recommended.

Comparison of Dentinal Wall Thickness in the Furcation Area (Danger Zone) in the First and Second Mesiobuccal Canals in the Maxillary First and Second Molars Using Cone-Beam Computed Tomography.

Objective: Differences in the morphology of the root canal system might result in favorable or adverse treatment outcomes. The present study compared the thickness of the dentinal wall in the danger zone (furcation area) of the first and second mesiobuccal canals in the maxillary first and second molars using cone beam computed tomography. Methods: In this cross-sectional study, 50 CBCT images of maxillary first and second molars were evaluated from one of the specialized radiology centers in Kerman, Iran. The images were prepared by a Planmeca Promax 3D Max machine (Planmeca, Helsinki, Finland), with a field of view (FOV) of 8×8 cm and a resolution of 0.1 mm and analyzed with Romexis Viewer software version 3.1.1 (Planmeca, Helsinki, Finland). In the 0.1-mm-thick axial cross-sections with a distance of 1 mm, the distances from the center of the MB1 and MB2 root canals to the furcation area were measured in three areas: A) furcation area, B) 2 mm below the furcation area, and C) 4 mm below the furcation area (at a magnification of ×10). The data were then analyzed with paired t-test. Results: The thickness of the dentinal wall in the MB2 root canal was significantly less than that in the MB1 root canal in all the specimens (P<0.05). In both maxillary first and second molars, the thicknesses of the MB1 and MB2 root canals were significantly different in the furcation area and 4 mm below the furcation area (P=0.001). There was no significant difference between the maxillary first and second molars 2 mm below the furcation area; however, the difference was marginal (P=0.07). Conclusion: Considering the low thickness of the dentinal wall in the MB2 root canal compared with the MB1 root canal in the maxillary first and second molars, the anti-curvature techniques away from the furcation should be used to prepare this root canal to reduce the risk of strip perforation. On the other hand, it might indicate that highly tapered instruments and other aggressive instruments, such as Gates-Glidden drills, should be used with caution in these root canals.

Postendodontic Pain after Pulpotomy or Root Canal Treatment in Mature Teeth with Carious Pulp Exposure: A Multicenter Randomized Controlled Trial.

This equivalence, randomized, clinical trial aimed to compare the postoperative pain of root canal therapy (RCT) with pulpotomy with mineral trioxide aggregate (PMTA) or calcium-enriched mixture (PCEM) in permanent mature teeth. In seven academic centers, 550 cariously exposed pulps were included and randomly allocated into PMTA (n = 188), PCEM (n = 194), or RCT (n = 168) arms. Preoperative "Pain Intensity" (PI) on Numerical Rating Scale and postoperative PIs until day 7 were recorded. Patients' demographic and pre-/intra-/postoperative factors/conditions were recorded/analysed. The arms were homogeneous in terms of demographics. The mean preoperative PIs were similar (P=0.998), the mean sum PIs recorded during 10 postoperative intervals were comparable (P=0.939), and the trend/changes in pain relief were parallel (P=0.821) in all study arms. The incidences of preoperative moderate-severe pain in RCT, PMTA, and PCEM arms were 56.5%, 55.7%, and 56.7%, which after 24 hours considerably decreased to 13.1%, 10.6%, and 12.9%, respectively (P=0.578). The time span of endodontic procedures was statistically different; RCT = 69.73, PMTA = 35.37, and PCEM = 33.62 minutes (P < 0.001). Patients with greater preoperative pain, symptomatic apical periodontitis, or presence of PDL widening suffered more pain (P=0.002, 0.035, and 0.023, resp.); however, other pre-/intra-/postoperative factors/conditions were comparable. Pulpotomy with MTA/CEM and RCT demonstrate comparable and effective postoperative pain relief.

The association between beverage consumption pattern and dental problems in Iranian adolescents: a cross sectional study.

BACKGROUND: With regard to the increasing consumption rates of unhealthy beverages among adolescents, the main purpose of the present study was to determine the association between beverage intake pattern and dental caries and tooth erosion in this age group. METHODS: A total sample of 600 adolescents was recruited in this study using a multistage cluster random sampling method in the city of Kerman, in the southeast of Iran, in 2017. Then, the Decayed, Missed and Filled Teeth (DMFT) index and the Tooth Wear Index (TWI) were registered for each participant. A Beverage Frequency Questionnaire was also employed to estimate typical beverage intake frequency. Correspondingly, negative binominal regression and logistic regression were performed to determine the independent variables associated with the DMFT index and the TWI. RESULTS: The findings revealed that the highest consumed beverage in daily living was tea in both genders, followed by sweetened soft beverages, as well as milk and kefir/yogurt drink. The results of the DMFT index were also significantly different in participants that had never consumed milk compared with those who had used milk on a daily basis. Moreover, the DMFT index in participants who had never consumed sweetened soft beverages was 39%, less than those who had had a daily intake of such beverages. Also, the chance of tooth erosion for participants who had never used sweetened soft beverages was 94%, lower than that in daily consumers. CONCLUSIONS: The results of this study revealed that adolescents had an unhealthy beverage intake pattern. Furthermore, milk consumption was beneficial to dental caries, whereas use of soft drinks associated with more dental caries and tooth erosion.

Potential Use of Microbial Surfactant in Microemulsion Drug Delivery System: A Systematic Review.

BACKGROUND: Microemulsions drug delivery systems (MDDS) have been known to increase the bioavailability of hydrophobic drugs. The main challenge of the MDDS is the development of an effective and safe system for drug carriage and delivery. Biosurfactants are preferred surface-active molecules because of their lower toxicity and safe characteristics when compared to synthetic surfactants. Glycolipid and lipopeptide are the most common biosurfactants that were tested for MDDS. The main goal of the present systematic review was to estimate the available evidence on the role of biosurfactant in the development of MDDS. SEARCH STRATEGY: Literature searches involved the main scientific databases and were focused on the period from 2005 until 2017. The Search filter composed of two items: "Biosurfactant" and/or "Microemulsion." INCLUSION CRITERIA: Twenty-four studies evaluating the use of biosurfactant in MDDS were eligible for inclusion. Among these 14 were related to the use of glycolipid biosurfactants in the MDDS formulations, while four reported using lipopeptide biosurfactants and six other related review articles. RESULTS: According to the output study parameters, biosurfactants acted as active stabilizers, hydrophilic or hydrophobic linkers and safety carriers in MDDS, and among them glycolipid biosurfactants had the most application in MDDS formulations. CONCLUSION: Synthetic surfactants could be replaced by biosurfactants as an effective bio-source for MDDS due to their excellent self-assembling and emulsifying activity properties.

Prevention of secondary caries by a new antibacterial compound.

BACKGROUND: Since secondary caries is one of the main problems of dental composites. The creation of an antibacterial property in these composites is essential. The objective of this study was to synthesize 3-(2, 5-dimethylfuran-3-yl)-1H-pyrazole-5(4H)-one and check its biocompatibility and antibacterial properties in flowable dental composites. MATERIALS AND METHODS: In this animal study, the antibacterial activity of flowable resin composites containing 0-5 wt% 3-(2,5-dimethylfuran-3-yl)-1H-pyrazole-5(4H)-one was investigated by using agar diffusion and direct contact tests on the cured resins. Statistical analysis was performed using one-way ANOVA test (P < 0.001). Thirty male albino Wistar rats were used, weighing 200-250 g. Animals were randomly divided into three groups of ten; each animal received three implants, 3-(2, 5-dimethylfuran-3-yl)-1H-pyrazole-5(4H)-one, penicillin V, and an empty polyethylene tube. A pathologist, without knowing the type of material tested and the timing of the test, examined the samples. Statistical analysis was performed using Kruskal-Wallis test (P < 0.001). RESULTS: According to our findings, although the agar diffusion test reveals no significant difference between the groups, the direct contact test demonstrates that, by increasing the 3-(2,5-dimethylfuran-3-yl)-1H-pyrazole-5(4H)-one content, the bacterial growth was significantly diminished and the 3-(2,5-dimethylfuran-3-yl)-1H-pyrazole-5(4H)-one has a good biocompatibility (P < 0.05). CONCLUSION: Incorporation of 3-(2,5-dimethylfuran-3-yl)-IH-pyrazole-5(4H)-one into flowable resin composites can be useful to prevent Streptococcus mutans activity.

Internet Addiction Among Iranian Students of Medical Sciences

Abstract Objective: To identify the prevalence of Internet addiction (IA) and associated factors among Iranian medical students. Material and Methods: The cross-sectional survey was conducted on a random sample of 400 students. The self-administered questionnaire consisted of two sections: the first section was sociodemographic data, data about student's relations, and Internet use characteristics; the second part aimed at assessment of the level of IA using Young's 20-item scale for IA. Data analyzed in SPSS 20 at 0.05 significant level. Results: Considering their familiarity with the Internet, 80.3% stated personal experience and 12.3% individuals stated educational periods held outside the university. The most locations of using the Internet were dormitories (21.0%) and houses (43.5%). Concerning hours of Internet use, 45.2% used the Internet more than two hours per day. One hundred sixty-eight individuals (42.0%) stated that they used the Internet less than 15% for university activities. One hundred eighty-eight individuals (47.0%) used VPN and 75.5% were dissatisfied with Internet speed 61.2%. A total of 64.3% had a poor dependency on the Internet and the prevalence of IA was 3.5%. The mean score of IA questionnaire was 43.98 ± 15.92 from 125. The mean score of IA was higher in the male sex, but there was no significant correlation between sex and IA (p>0.05). There was not a significant correlation between the field of study and the year of entrance. Conclusion: The prevalence of Internet addiction among medical students was low. Identification of factors associated with IA can help in the planning of preventive programs to raise students' knowledge about the hazards IA.

Probability of Publication Bias in Published Articles Resulting from Dental Dissertations of Medical Sciences Universities in Iran

Abstract Objective: To evaluate the association of publication bias with obtaining positive or negative results in the Doctoral thesis of Iranian dental schools. Material and Methods: In this cross-sectional study firstly we collected all the abstracts of Doctoral and post-doctoral thesis belonging to electronic archives of five Iranian dental schools there after the analytic abstracts were included and in the second phase, we try to search resulting articles with searching in Google Scholar. Data were analyzed using descriptive statistics and a Chi-squared test, Pearson's correlation coefficient, Fisher's exact test, and Logistic Regression Results: Out of 483 reviewed thesis abstracts 269 cases were included (55.7%) 153 of which were accessible as papers (56.9%). In 67.7% of the reviewed thesis, positive results were obtained. There were significant relationships between publishing and publishing in international journals with two variables: Study type and field (p<0.05). In vitro studies, clinical trials and studies in the field of oral diseases and periodontics had a higher rate of publication in the form of articles. Retrospective studies and those in the fields of endodontics and oral pathology had a higher rate of publication in journals with international indexes. Using regression logistic model showed that the probability of publishing positive data was greater (18-31%) than negative data. It was shown that the specialty field affected the relationship between the chance of publication of the article and the positive/negative results (p=0.008), increasing the chance of publication to 31% Conclusion: There was publication bias in reviewed dental articles.