Critical appraisal of confounding factors of observational studies on the association between dentofacial features and dental trauma in a Brazilian population.

AIMS/OBJECTIVES: Dental trauma is a highly prevalent dental emergency. Children and adolescents without inadequate lip coverage, increased overjet, and anterior open bite are associated with the occurrence of traumatic dental injuries. Observational studies do not allow the inference of causality, one of the reasons being: the potential confounding factors. Therefore, this review aimed to critically appraise the confounding factors considered in epidemiological studies that associate dentofacial features with the occurrence of dental trauma in Brazilian children and adolescents. METHODS: Studies included in the qualitative synthesis of a recently published comprehensive systematic review and meta-analysis on the topic were screened. Studies that only mentioned the performance of bivariate analyzes or that did not mention the performance of multivariate analyzes were excluded. Evaluation of control statements for possible confounders and bias consideration was performed for each selected study. Confounding factors in these studies were also identified and categorized according to their domains. RESULTS: Fifty-five observational studies were screened, of which 11 were excluded due to the mention of only bivariate analyzes or the lack of multivariate analyses. The remaining 44 studies were critically appraised. Of these, 9 studies specifically mentioned the term confounding, and 12 studies mentioned the term bias. However, only 14 studies mentioned limitations on confounding factors in their findings. Among the 99 different variables identified, the most used were type of trauma, followed by sex and age. CONCLUSION: Most studies did not acknowledge the control for possible confounding factors and rarely stressed the need for caution in interpreting their results. Cross-sectional studies do not allow inferring a cause-and-effect relationship between dentofacial features and dental trauma.

Comparison of the effect of photobiomodulation therapy and Ibuprofen on postoperative pain after endodontic treatment: randomized, controlled, clinical study.

The aim of the study was to compare the effect of Ibuprofen and the application of photobiomodulation therapy protocol on the reduction of postoperative pain in endodontically treated teeth using a randomized clinical trial design. Seventy patients, diagnosed with symptomatic irreversible pulpitis, were selected. Treatment was performed by a single operator; a reciprocal system was used to prepare the canals; they were obturated using the Tagger's hybrid technique and coronally sealed with glass-ionomer cement. After treatment, patients were randomly divided into 2 groups. In the active control group, two Ibuprofen 600 mg tablets were administered within a 12-h interval. In the photobiomodulation therapy group, the irradiation was applied after treatment. The evaluation of postoperative pain was performed by another researcher blinded to the groups at 6, 12, 24, and 72 h intervals after treatment. To measure the outcome, two pain scales were used: numerical rate scale (NRS) and verbal rate scale (VRS). Data were analyzed using the chi-square, Mann-Whitney, and Wilcoxon paired tests. Outcome was superior with photobiomodulation therapy at 6 h (p < 0.001), 12 h (p = 0.005), and 24 h (p < 0.001) intervals compared with Ibuprofen. The results for the 72 h (p = 0.317) interval were similar, both in the VRS and NRS scales. It may be concluded that the use of photobiomodulation therapy was effective in reducing pain within the first 24 h when compared with the administration of Ibuprofen 600 mg.

Effect of photobiomodulation therapy on postoperative pain after endodontic treatment: a randomized, controlled, clinical study.

OBJECTIVE: The aim of this prospective, randomized, clinical study was to assess the effect of photobiomodulation therapy (PBM) with low-level laser irradiation (LLLI) on postoperative pain after endodontic treatment. MATERIALS AND METHODS: Sixty patients, diagnosed with irreversible pulpitis in lower molar teeth, participated in the study. All treatments were performed by a single operator. Participants were randomly divided into two groups: in the experimental group (EG), endodontic treatment was performed with a reciprocating system, immediately followed by PBM with LLLI; and only endodontic treatment was performed in the control group (CG). Postoperative pain was assessed by a second examiner, who was blinded, using two scales: verbal rating scale (VRS) and numerical rating scale (NRS). Assessment was carried out at 6, 12, and 24 h after treatment. Data were analyzed using chi-squared, Fisher's exact, Mann-Whitney tests, ordinal, and non-parametric regression analyses. RESULTS: For the prevalence of pain, the difference between the groups was significant for the evaluations performed after 6 h (p = 0.04) and 24 h (p = 0.02). The difference after 24 h remained significant after stratification by sex and extrusion of filling material. Increased pain intensity was associated with extrusion of root canal filling material to the periapical region in the two scales used. CONCLUSION: The effect of PBM therapy after endodontic treatment showed a significant decreasein prevalence of postoperative pain. CLINICAL RELEVANCE: The PBM reduces the prevalence of postoperative pain and may benefit patients who need endodontic treatment.

Technological advances in endodontics: treatment of a mandibular molar with internal root resorption using a reciprocating single-file system.

The field of endodontics has become increasingly successful due to technological advances that allow clinicians to solve clinical cases that would have been problematic a few years ago. Despite such advances, endodontic treatment of teeth with internal root resorption remains challenging. This article presents a clinical case in which a reciprocating single-file system was used for endodontic treatment of a mandibular molar with internal root resorption. Radiographic examination revealed the presence of internal root resorption in the distobuccal root canal of the mandibular right first molar. A reciprocating single-file system was used for root canal instrumentation and final preparation, and filling was obtained through a thermal compaction technique. No painful symptoms or periapical lesions were observed in 12 months of follow-up. The results indicate that a reciprocating single-file system is an adequate alternative for root canal instrumentation, particularly in teeth with internal root resorption.

Contamination of absorbent paper points in clinical practice: a critical approach.

This study sought to evaluate the contamination level of absorbent paper points used routinely in dental clinical practice. For this study, 60 absorbent paper points were collected and separated into 3 groups: 20 paper points from sealed commercial packages (Group 1), 20 paper points from open commercial packages in use for 30 days (Group 2), and 20 paper points from a sealed commercial package that were manipulated by the operator (Group 3). Evaluation criteria was the presence or absence of turbidity in the brain heart infusion (BHI) broth used as the culture medium. The results (Kruskal-Wallis test; significance level = 5%) demonstrated bacterial growth in most of the samples for all groups, with a statistically significant difference in Group 3 compared to Groups 1 and 2. It was concluded that inadequate manipulation of paper points by the operator caused these materials to become contaminated; in addition, the bacterial growth in absorbent paper points that are still in their commercial packages indicates the importance of sterilization before the paper points are used in clinical practice.

Association between the prevalence of pulp stones and calcified atherosclerotic plaques: a systematic review and meta-analysis.

OBJECTIVE: To evaluate the association between the prevalence of pulp stones (PS) in permanent teeth and calcified atherosclerotic plaques (CAP). METHODS: An electronic search was performed in 10 databases to locate observational studies that investigated the association between PS in permanent teeth and CAP, published until March 2022. Two reviewers performed the search, selection and extraction of data from eligible studies. The individual risk of bias of eligible studies was assessed using the JBI Critical Appraisal Tools. The meta-analysis was conducted using fixed and random effects and odds ratio (OR) as an effect measure with a 95% confidence interval (CI). The heterogeneity between the studies was quantified using the I² test. The certainty of evidence was evaluated using the GRADE approach. RESULTS: The electronic search resulted in 2968 records, of which only 7 studies were considered eligible. The total sample consisted of 3770 participants from 5 countries. All studies showed biases of confounding factors and exposure assessment. Based on six studies and with very low certainty of evidence, the meta-analysis showed that patients with PS were more likely to also have CAP in carotid or coronary arteries (OR: 1.70; 95% CI: 1.21; 2.38, I² = 0%). CONCLUSIONS: Limited evidence suggests that there is a positive association between the prevalence of PS in permanent teeth detected using panoramic radiography and CAP in the coronary or carotid arteries.

Prevalence of dental caries, periodontal disease, malocclusion, and tooth wear in indigenous populations in Brazil: a systematic review and meta-analysis.

The aim of this review was to evaluate the prevalence of dental caries, periodontal disease, malocclusion, and tooth wear in indigenous in Brazil. A systematic review of observational studies was performed according to the PRISMA guidelines (CRD42020218704). The search strategy involved the electronic databases of Embase, LILACS, PubMed, Web of Science, Scopus, and the CAPES Theses and Dissertations for gray literature. The eligibility criteria consisted of publications that assessed the prevalence of oral conditions in indigenous populations in Brazil. Studies with indigenous people living in urban area were excluded. The risk of bias was evaluated by using JBI Critical Appraisal for prevalence studies. Thirty studies were included in the review, and the majority showed a low risk of bias. A meta-analysis of 20 studies was conducted using the random-effects model and a 95% confidence interval. Several ethnicities were studied in isolation or in groups (n = 7,627 for dental caries; n = 2,774 for periodontal disease; n = 1,067 for malocclusion; n = 150 for tooth wear). The prevalence of caries ranged from 50% among indigenous people aged 18-36 months to 100% among those aged 65-74 years. The prevalence of periodontal disease ranged from 58% to 83%. The prevalence of malocclusion was 43%. Tooth wear was assessed in only one ethnic group and showed a prevalence of 100% in indigenous people aged >18 years. The certainty of evidence assessed by the GRADE system ranged from very low to moderate. This systematic review showed significant differences in the prevalence of dental caries, periodontal disease and malocclusion between indigenous population groups and territories in which indigenous people live.

Shaping Ability of Reciprocating and Rotary Systems After Root Canal Retreatment: a CBCT Study.

The purpose of this in vitro study was to evaluate the shaping ability of reciprocating and continuous rotary systems after root canal retreatment. After preparation and root canal filling, mesial canals of 54 mandibular molars were distributed into 3 groups (n=18), according to the filling material removal and re-instrumentation protocols: WOG group - WaveOne Gold system; PTN group - ProTaper Next system; and PTU group - ProTaper Universal system. Cone-beam computed tomographic (CBCT) images acquisition of the mesial root canals was performed at different moments: (1) before instrumentation (unprepared root canals), (2) after preparation and filling, (3) after filling material removal and (4) re-instrumentation. The apical transportation (AT), centering ability (CA) and change in root canal diameter were assessed by CBCT analysis. The remaining filling material quantification was performed by radiographic examination. The statistical analyses were performed using the 3-way ANOVA, Tukey-Kramer, Kruskal-Wallis and Dunn multiple Comparison tests (p<0.05). The tested instruments did not show full CA (=1.0). PTN group had greater AT at the 5th mm in comparison with the WOG group (p<0.05). After re-instrumentation, WOG group had greater root canal diameter change at the 1st and 5th mm than PTN and PTU groups (p<0.05). There was no significant difference among groups when comparing the amount of remaining filling material after re-instrumentation (p>0.05). The tested systems provided minimal alteration in root canal morphology at the apical portion after root canal retreatment. However, WOG promoted greater change in root canal diameter.

CONSORT Compliance in Randomized Clinical Trials of Regenerative Endodontic Treatments of Necrotic Immature Teeth: A Scoping Review.

INTRODUCTION: This study aimed to investigate methodological quality of clinical trials in regenerative endodontics and its compliance with the CONSORT statement. METHODS: An electronic search was performed in 8 electronic databases. Only clinical trials whose participants underwent regenerative endodontic treatment on necrotic permanent immature teeth were included. Quality assessment was performed using the Cochrane Collaboration's Risk of Bias Tool (RoB, version 2.0). Compliance of articles with the CONSORT guidelines was assessed by a tool with scales: 0 = no description, 1 = deficient, and 2 = adequate description, totaling a maximum score of 32 points. The Mann-Whitney and Kruskal-Wallis tests were used to compare the scores among journals, studies, country, income levels, and publication periods. Spearman correlation analyses were performed between CONSORT compliance scores and 2019 journal CiteScore values, publication year, and quality assessment. RESULTS: Twenty studies were included. The average CONSORT compliance score was 20.95 (±6.19). The better reported items were the description of the interventions performed in the trials (100%), followed by the description of the number of patients analyzed, losses and exclusions (90%), and the hypothesis tested (85%). Within the 20 studies, 3 articles were classified as "low risk of bias," 8 studies were classified as "some concerns," and 9 studies were considered "high risk of bias." Studies carried out in countries with higher income levels presented higher CONSORT scores. Significant moderate correlations were found between the CONSORT score and the percentage of risk of bias in low-risk domains (rs = 0.63; 95% CI, 0.31-0.94; P = .003) and the overall risk of bias categories (rs = 0.76; 95% CI, 0.54-0.98; P = .001). CONCLUSIONS: The adequacy of reporting based on the CONSORT checklist items of regenerative endodontic trials was low with a moderate to high risk of bias.

Calcium Silicate-Based Sealers Do Not Reduce the Risk and Intensity of Postoperative Pain after Root Canal Treatment when Compared with Epoxy Resin-Based Sealers: A Systematic Review and Meta-Analysis.

This review aims to evaluate whether root canal obturation with calcium silicate-based (CSB) sealers reduces the risk and intensity of endodontic postoperative pain when compared to epoxy resin-based (ERB) sealers. The review was registered at PROSPERO (CRD42020169255). Two independent reviewers conducted an electronic search in PubMed, Scopus, EMBASE, Web of Science, Cochrane Library and LILACS until November 2020 and included only randomized clinical trials with adult health participants undergoing root canal treatment. After selection, the JBI Critical Appraisal tool was used to assess the risk of bias. A fixed-effect meta-analysis was performed to summarize the results of pain risk and pain intensity at time intervals of 24 and 48 hours. Finally, the certainty of evidence was assessed using the GRADE approach. The search resulted in 1,206 records, of which five studies (n = 421 patients) met the eligibility criteria and presented moderate to low risk of bias. There was no significant difference between groups in the risk of pain in the first 24 hours (relative risk or RR = 0.83, 95% confidence interval or CI: 0.60, 1.16, I 2 =) or 48 hours (RR = 0.56, 95% CI: 0.26, 1.21, I 2 =). Silicate-based sealers led to lower pain intensity only at 48 hours (mean and standard deviation = 0.37, 95% CI: 0.69, 0.05). All analyses revealed low heterogeneity (I 2 < 25%). The evidence presented moderate level of certainty. Currently available evidence has shown that there is no difference between CSB and ERB sealers in the risk or intensity of postoperative pain.

Effect of Occlusal Adjustment on Postoperative Pain after Root Canal Treatment: A Randomized Clinical Trial.

The aim of this prospective, randomized, clinical study was to analyze the influence of occlusal adjustment on the prevalence of postoperative pain after endodontic treatment. Seventy-eight patients, diagnosed with symptomatic irreversible pulpitis with indication for endodontic treatment, were selected to participate in the study. The participants were randomized and divided into two groups: in the occlusal adjustment group (OAG), endodontic treatment was performed with subsequent occlusal adjustment. In the control group (CG), endodontic treatment was performed without occlusal adjustment. Treatments were performed by the same operator. Pain occurrence and intensity were recorded on two scales: the verbal rating scale (VRS) and numerical rating scale (NRS). Pain assessment was carried out by a second examiner, blinded to the experiment, 6, 24 and 72 h after endodontic treatment. Data were analyzed using Mann-Whitney, chi-squared, and Fisher's exact tests. In the occlusal adjustment group, 71.1% reported postoperative pain and 67.5% reported pain in the control group. At the 6-hour assessment, 21 individuals reported pain in the occlusal adjustment group and 24 in the control group (p=0.672). At the 24-hour assessment, 18 and 19 individuals reported pain (p=0.991) and at the 72-hour assessment, 8 and 4 reported pain (p=0.219), respectively. Occlusal adjustment did not influence the prevalence of postoperative pain of endodontically treated teeth with symptomatic irreversible pulpitis.

Apical Transportation and Centering Ability After Root Canal Filling Removal Using Reciprocating and Continuous Rotary Systems: A CBCT Study.

OBJECTIVE: To evaluate the apical transportation and centering ability promoted by reciprocating and continuous rotary systems after root canal filling removal. MATERIALS AND METHODS: After obturation, 40 mesial root canals of mandibular molars were distributed into four groups (n = 20) for filling material removal: PTU group-F2 instrument (25.08) of ProTaper Universal system; R25 group-R25 instrument (25.08) of Reciproc system; X2 group-X2 instrument (25.06) of ProTaper Next system and X3 group-X2 instrument (25.06) of ProTaper Next system, followed by X3 instrument (30.07). Cone-beam computed tomographic analysis was performed before and after filling material removal for acquisition of apical images. Apical transportation (AT) and its direction, and centering ability (CA), were assessed using the equations AT = (X1-X2)-(Y1-Y2) and CA = (X1-X2/Y1-Y2 or Y1-Y2/X1-X2), respectively. Data were submitted to the nonparametric Kruskal-Wallis and Dunn multiple comparison tests (p < 0.05) for statistical analysis. RESULTS: There was no statistically significant difference among groups for AT (p > 0.05), with a tendency toward transportation in the distal direction. Also, there was no statistically significant difference among groups regarding CA (p > 0.05). CONCLUSIONS: The different systems, including ProTaper Next, caused AT within the acceptable clinical limit after filling removal. In addition, none of the tested systems presented adequate CA.

Prevalence of dental caries, periodontal disease, malocclusion, and tooth wear in indigenous populations in Brazil: a systematic review and meta-analysis

Abstract The aim of this review was to evaluate the prevalence of dental caries, periodontal disease, malocclusion, and tooth wear in indigenous in Brazil. A systematic review of observational studies was performed according to the PRISMA guidelines (CRD42020218704). The search strategy involved the electronic databases of Embase, LILACS, PubMed, Web of Science, Scopus, and the CAPES Theses and Dissertations for gray literature. The eligibility criteria consisted of publications that assessed the prevalence of oral conditions in indigenous populations in Brazil. Studies with indigenous people living in urban area were excluded. The risk of bias was evaluated by using JBI Critical Appraisal for prevalence studies. Thirty studies were included in the review, and the majority showed a low risk of bias. A meta-analysis of 20 studies was conducted using the random-effects model and a 95% confidence interval. Several ethnicities were studied in isolation or in groups (n = 7,627 for dental caries; n = 2,774 for periodontal disease; n = 1,067 for malocclusion; n = 150 for tooth wear). The prevalence of caries ranged from 50% among indigenous people aged 18-36 months to 100% among those aged 65-74 years. The prevalence of periodontal disease ranged from 58% to 83%. The prevalence of malocclusion was 43%. Tooth wear was assessed in only one ethnic group and showed a prevalence of 100% in indigenous people aged >18 years. The certainty of evidence assessed by the GRADE system ranged from very low to moderate. This systematic review showed significant differences in the prevalence of dental caries, periodontal disease and malocclusion between indigenous population groups and territories in which indigenous people live.

Shaping Ability of Reciprocating and Rotary Systems After Root Canal Retreatment: a CBCT Study

Abstract The purpose of this in vitro study was to evaluate the shaping ability of reciprocating and continuous rotary systems after root canal retreatment. After preparation and root canal filling, mesial canals of 54 mandibular molars were distributed into 3 groups (n=18), according to the filling material removal and re-instrumentation protocols: WOG group - WaveOne Gold system; PTN group - ProTaper Next system; and PTU group - ProTaper Universal system. Cone-beam computed tomographic (CBCT) images acquisition of the mesial root canals was performed at different moments: (1) before instrumentation (unprepared root canals), (2) after preparation and filling, (3) after filling material removal and (4) re-instrumentation. The apical transportation (AT), centering ability (CA) and change in root canal diameter were assessed by CBCT analysis. The remaining filling material quantification was performed by radiographic examination. The statistical analyses were performed using the 3-way ANOVA, Tukey-Kramer, Kruskal-Wallis and Dunn multiple Comparison tests (p<0.05). The tested instruments did not show full CA (=1.0). PTN group had greater AT at the 5th mm in comparison with the WOG group (p<0.05). After re-instrumentation, WOG group had greater root canal diameter change at the 1st and 5th mm than PTN and PTU groups (p<0.05). There was no significant difference among groups when comparing the amount of remaining filling material after re-instrumentation (p>0.05). The tested systems provided minimal alteration in root canal morphology at the apical portion after root canal retreatment. However, WOG promoted greater change in root canal diameter.

Resumo O objetivo deste estudo in vitro foi avaliar a capacidade de modelagem de sistemas rotatórios e reciprocantes após o retratamento do canal radicular. Após o preparo e obturação do canal radicular, os canais mesiais de 54 molares inferiores foram distribuídos em 3 grupos, de acordo com os protocolos de remoção do material obturador e re-instrumentação: (n=18): grupo WOG - sistema WaveOne Gold; Grupo PTN - sistema ProTaper Next; e grupo PTU - sistema ProTaper Universal. A análise das imagens de tomografia computadorizada de feixe cônico foi realizada em diferentes momentos: (1) antes da instrumentação (canais radiculares não preparados), (2) após o preparo e obturação, (3) após a remoção do material obturador e (4) re-instrumentação. O transporte apical (TA), a capacidade de centralização (CC) e a mudança no diâmetro do canal radicular foram avaliados por análise tomográfica. A quantificação do restante do material obturador foi realizada por exame radiográfico. As análises estatísticas foram realizadas utilizando os testes de ANOVA de 3 fatores, Tukey-Kramer, Kruskal-Wallis e Comparações Múltiplas de Dunn (p<0,05). Os instrumentos não apresentaram CC perfeita (=1,0). PTN apresentou maior TA no 5º mm em comparação ao grupo WOG (p<0,05). Após a re-instrumentação, o grupo WOG apresentou maior aumento no diâmetro do canal radicular no 1° e 5° mm do que os grupos PTN e PTU. Não houve diferença significativa entre os grupos em relação à remoção do material obturador (p>0,05). Os sistemas testados proporcionaram alteração mínima na morfologia do canal radicular na porção apical após o retratamento do canal radicular. No entanto, WOG promoveu maior alteração no diâmetro do canal radicular.

Assessment of a Cavity to Optimize Ultrasonic Efficiency to Remove Intraradicular Posts.

INTRODUCTION: The study assessed an in vitro protocol for the removal of cast metal posts using ultrasonic vibration in multirooted teeth by drilling a cavity in the coronal portion of the post followed by ultrasound application in the cavity. METHOD: Forty endodontically treated molars received intraradicular cast posts and were divided into 4 groups according to the removal protocol: the control group, no cavity and no ultrasonic vibration; the ultrasonic group, no cavity and ultrasonic vibration in the coronal portion of the core; the cavity group, a cavity in the core and no ultrasonic vibration; and the cavity ultrasonic group, a cavity in the core and ultrasonic vibration inside the cavity. The traction test was performed on all samples using a universal testing machine (EMIC DL-2000; EMIC Equipamentos e Sistemas de Ensaio LTDA, São José dos Pinhais, PR, Brazil) at a speed of 1 mm/min, obtaining values in Newtons. The data were statistically analyzed using analysis of variance and the Tukey-Kramer test (P < .05). RESULTS: The results showed statistically significant differences between the tested groups (control group = 322.74 N, ultrasonic group = 283.09 N, cavity group = 244.00 N, and cavity ultrasonic group = 237.69 N). The lowest mean strength was found in the group that received ultrasonic vibration inside the cavity. CONCLUSIONS: Preparing a cavity in the coronal core followed by ultrasonic vibration reduces the traction force required for removal. The removal protocol was effective for removing posts in multirooted teeth cemented with zinc phosphate.

Surface characteristics of reciprocating instruments before and after use--a SEM analysis.

The presence of debris, defects and deformations of endodontic reciprocating instruments before and after chemical-mechanical preparation (MCP) was analyzed using scanning electron microscopy (SEM). The following 26 instruments were divided into 2 groups: Waveone (n=13) and Reciproc (n=13) and examined by SEM (150 x magnification) prior to canal preparation at 2 and 4 mm from the tip. The instruments were used in the preparation of mesial root canals of 26 extracted human permanent mandibular molars. The instruments were then washed in ultrasonic bath and subjected to new microscopic analysis of debris and deformation by a score that used the presence or absence of irregular edges, grooves, microcavities and burrs as criteria. After the SEM analysis and with the scores of the examiners, the collected data were subjected to descriptive statistical analysis using the Kruskall-Walis and Mann Whitney test at a 5% significance level. All instruments examined presented debris before and after use. A statistically significant difference was found for defects and deformation between the groups (p<0.05). The presence of defects and deformities was higher in the WaveOne instruments, and Reciproc instruments presented a lower rate.

Apical Transportation, Centering Ability, and Cleaning Effectiveness of Reciprocating Single-file System Associated with Different Glide Path Techniques.

INTRODUCTION: The aim of this study was to evaluate the apical transportation, the centering ability, and the cleaning effectiveness of a reciprocating single-file system associated to different glide path techniques. METHODS: The mesial root canals of 52 mandibular molars were randomly distributed into 4 groups (n = 13) according to the different glide path techniques used before biomechanical preparation with Reciproc System (RS): KF/RS (sizes 10 and 15 K-files), NGP/RS (no glide path, only reciprocating system), PF/RS (sizes 13, 16, and 19 PathFile instruments), and NP (no preparation). Cone-beam computed tomography analysis was performed before and after instrumentation for apical third images acquisition. Apical transportation and its direction were evaluated by using the formula D = (X1 - X2) - (Y1 - Y2), and the centering ability was analyzed by the formula CC = (X1 - X2/Y1 - Y2 or Y1 - Y2/X1 - X2). The samples were submitted to histologic processing and analyzed under a digital microscope for debris quantification. The values were statistically analyzed (Kruskal-Wallis, the Dunn multiple comparisons test, P < .05). RESULTS: All groups had similar apical transportation values, with no significant difference among them (P > .05). Groups had a tendency toward transportation in the mesial direction. No technique had perfect centering ability (=1.0), with no significant difference among them. KF/RS had larger amount of debris, with statistically significant difference in comparison with NGP/RS (P > .05). CONCLUSIONS: The different glide path techniques promoted minimal apical transportation, and the reciprocating single-file system tested remained relatively centralized within the root canal. Also, the different techniques interfered in the cleaning effectiveness of the reciprocating system.

Apical transportation of manual NiTi instruments and a hybrid technique in severely curved simulated canals.

AIM: To evaluate the apical transportation induced by two instrumentation techniques in severely curved simulated canals. MATERIALS AND METHODS: Forty simulated canals were divided into two groups (n = 20), according to the following instrumentation techniques: ProTaper Universal Manual System and a hybrid technique. The simulated canals in the ProTaper group were prepared following the technique recommended by the manufacturer: SX files in the cervical third of the root canal and S1, S2, and F1 files up to the working length. In the hybrid group, preparation was performed with K-files sizes 15, 20, and 25 to the working length, followed by cervical preparation with Gates Glidden burs 1, 2, and 3. Apical finishing was performed with the ProTaper manual files S2 and F1. To analyze apical transportation, the simulated canals were photographed before and after preparation at ×8. The images of the root canals pre- and post-instrumentation were superimposed to measure the distance between the inner and outer walls along the first 3 mm of the apical third. RESULTS: The hybrid group presented the highest apical transportation values; however, with no statistically significant difference in comparison with the ProTaper group (P > 0.05). CONCLUSIONS: Both techniques induced similar apical transportation in the original path of the simulated root canals.

Evaluation of a new protocol for removing metal retainers from multirooted teeth.

INTRODUCTION: The aim of this study was to evaluate in vitro a new protocol for removing intraradicular retainers from multirooted teeth applying ultrasonic vibration. METHODS: Forty mandibular molars were endodontically treated to receive cast intraradicular retainers, which were distributed into the following 4 groups: group 1: control without a slot and without ultrasound, group 2: control with a slot and without ultrasound, group 3: ultrasonic vibration in the core without a slot, and group 4: ultrasonic vibration in the core with a slot. After the intraradicular retainers were cemented with zinc phosphate, ultrasonic vibration was applied for 1 minute. The test specimens were then submitted to the traction test in the universal testing machine at a speed of 1 mm/min. The maximum traction force required to remove the intraradicular retainer was recorded in newtons, and the data were statistically analyzed using analysis of variance and the Tukey-Kramer test (P < .05). RESULTS: The results showed statistically significant differences among the groups tested (group 1 = 234.34 N, group 2 = 201.67 N, group 3 = 139.57 N, and group 4 = 83.23 N). The lowest mean value of traction force recorded was when ultrasonic vibration was applied on the core with a slot. CONCLUSIONS: Creating a slot in the core and the ultrasound application on all surfaces and inside the slot reduced the force required for removing intraradicular metal retainers from multirooted teeth cemented with zinc phosphate.

Effect of occlusal adjustment on postoperative pain after root canal treatment: a randomized clinical trial

Abstract The aim of this prospective, randomized, clinical study was to analyze the influence of occlusal adjustment on the prevalence of postoperative pain after endodontic treatment. Seventy-eight patients, diagnosed with symptomatic irreversible pulpitis with indication for endodontic treatment, were selected to participate in the study. The participants were randomized and divided into two groups: in the occlusal adjustment group (OAG), endodontic treatment was performed with subsequent occlusal adjustment. In the control group (CG), endodontic treatment was performed without occlusal adjustment. Treatments were performed by the same operator. Pain occurrence and intensity were recorded on two scales: the verbal rating scale (VRS) and numerical rating scale (NRS). Pain assessment was carried out by a second examiner, blinded to the experiment, 6, 24 and 72 h after endodontic treatment. Data were analyzed using Mann-Whitney, chi-squared, and Fisher's exact tests. In the occlusal adjustment group, 71.1% reported postoperative pain and 67.5% reported pain in the control group. At the 6-hour assessment, 21 individuals reported pain in the occlusal adjustment group and 24 in the control group (p=0.672). At the 24-hour assessment, 18 and 19 individuals reported pain (p=0.991) and at the 72-hour assessment, 8 and 4 reported pain (p=0.219), respectively. Occlusal adjustment did not influence the prevalence of postoperative pain of endodontically treated teeth with symptomatic irreversible pulpitis.

Resumo O objetivo deste estudo prospectivo, randomizado e clínico foi analisar a influência do ajuste oclusal na prevalência de dor pós-operatória após o tratamento endodôntico. Setenta e oito pacientes, diagnosticados com pulpite irreversível sintomática com indicação de tratamento endodôntico, foram selecionados para participar do estudo. Os participantes foram randomizados e divididos em dois grupos: no grupo de ajuste oclusal (GAO), foi realizado tratamento endodôntico com posterior ajuste oclusal. No grupo controle (GC), o tratamento endodôntico foi realizado sem ajuste oclusal. Os tratamentos foram realizados pelo mesmo operador. A ocorrência e a intensidade da dor foram registradas em duas escalas: a escala de classificação verbal (VRS) e a escala de classificação numérica (NRS). A avaliação da dor foi realizada por um segundo examinador, cego para o experimento, 6, 24 e 72 horas após o tratamento endodôntico. Os dados foram analisados utilizando testes de Mann-Whitney, qui-quadrado e exato de Fisher. No grupo de ajuste oclusal, 71,1% relataram dor pós-operatória e 67,5% relataram dor no grupo controle. Na avaliação de 6 horas, 21 indivíduos relataram dor no grupo de ajuste oclusal e 24 no grupo controle (p=0,672). Na avaliação de 24 horas, 18 e 19 indivíduos relataram dor (p=0,991) e, na avaliação de 72 horas, 8 e 4 relataram dor (p=0,219), respectivamente. O ajuste oclusal não influenciou a prevalência de dor pós-operatória após o tratamento endodôntico em dentes com pulpite irreversível sintomática.