A laboratory study comparing the static navigation technique using a bur with a conventional freehand technique using ultrasonic tips for the removal of fibre posts.

AIM: There are currently no high-quality studies comparing the static navigation technique with conventional methods of fibre post removal. The aim of this ex vivo study was to compare the effectiveness of fibre post removal between a static navigation technique and a conventional freehand technique using ultrasonics by experienced and inexperienced operators. METHODOLOGY: Forty-eight extracted single-rooted human premolars were root-filled. A fibre post was cemented in all 48 teeth, which were then divided randomly into the following groups: static navigation group using burs; static navigation-ultrasonic group; and non-guided group using ultrasonic tips. The following parameters were evaluated for both experienced operators and inexperienced operators: reaching the gutta-percha root filling successfully, the time required to remove the entire post, the occurrence of lateral root perforations, and the amount of root dentine removed. The Kolmogorov-Smirnov test was used to examine the normality of the data; the anova test was used to compare the significant differences among groups; and Tukey tests were used for all two-by-two comparisons. The significance level was set at 0.05. RESULTS: In the static navigation group, the gutta-percha was reached significantly more frequently than in the non-guided group (p < .05). The static navigation approach required significantly less time than the non-guided approach to reach the gutta-percha (p < .05). The total removal of posts was significantly different between groups (p < .05), but there was no significant difference between experienced and inexperienced operators in the static navigation group (p > .05). More perforations were associated with the non-guided group than with the other two groups. The total mean loss of dentine in the non-guided group in all directions was 0.39 (±0.17) mm, with 0.25 (±0.09) mm for experienced, and 0.42 (±0.16) mm for inexperienced operators. CONCLUSION: When compared to a conventional ultrasonic technique for the removal of fibre posts, the static navigation method using burs resulted in less dentine removal, more rapid access to the gutta-percha root filling, less overall time to remove the posts, and fewer complications. When using static navigation, there was no difference in performance between experienced and inexperienced operators.

Microcomputed tomographic evaluation of 6 NiTi files on the pericervical dentin and the smallest dentin thickness zones in mesial root canals of mandibular molars: an in vitro study.

OBJECTIVE: The aim of this study was to evaluate six files on the pericervical dentin (PCD) and the smallest dentin thickness zones (SDTZ) in mesial root canals of mandibular molars. MATERIALS AND METHODS: Sixty mandibular molars with two mesial canals and Vertucci configuration were aleatory allocated in 6 experimental groups of 10 molars and 20 root canals. Specimens were scanned before instrumentation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WaveOne Gold (WG), group 2 with Reciproc Blue (RB), group 3 with TRUShape (TS), group 4 with XP-endo Shaper (XP), group 5 with iRace (IR), and group 6 with TruNatomy (TN). After instrumentation, the molars were scanned again and the images recorded were reconstructed with the NRecon v.1.7 (Bruker micro-CT) and analyzed with CTAn v.1.20.8 software (Bruker micro-CT) quantifying the changes produced in the surface, volume, structure thickness, SMI, and centroids at the Pericervical Dentin area of the root canals (PCD) located from the root canal orifices at the floor of the pulp chamber to 4 mm in the apical direction, and the changes in the Smallest Dentin Thickness Zones (SDTZ) located (from the furcation to 4 mm and 7 mm in the apical direction. The data obtained were compared using Wilcoxon and ANOVA with a 5% significance level. RESULTS: XP and TN were similar in all the parameters (P >.05) at the PCD, but TN showed significant differences from WG, RB, TS, and IR (P <.05), while XP showed significant differences from WG (P <.05) in volume, surface, and structure thickness. Regarding the changes in the SDTZ, the amount of dentin removed was similar between the groups in both canals at the middle 1/3, at the cervical 1/3 for MB canals, and in ML canals for RB, TS, XP, IR, and TN (P>.05). The action of WG was significantly different from that of XP and TN in the cervical 1/3 of the ML canal (P <.05). CONCLUSIONS: XP and TN rotatory files with small taper and volume maintained better with minor changes at the PCD and SDTZ, while WG reciprocation file produced the largest change. All the files were maintained centered at the PCD, and their performances were safe with a minimal thickness higher 0.5 mm at the SDTZ, and without risk of perforation. TRIAL REGISTRATION: No clinical trials were indicated in this study. CLINICAL RELEVANCE: The choice of endodontic files is a relevant factor in the conservative performance of root canal treatments.

Outcome of root canal retreatment filled with gutta-percha techniques: A systematic review and meta-analysis.

OBJECTIVE: The present systematic review and meta-analysis aimed to evaluate the success rate of root canal retreatment filled with gutta-percha and the variables related to retreatment success. DATA: The PRISMA guidelines were followed for the present review. The study protocol was registered in the International Prospective Database of Systematic Reviews (PROSPERO CRD42021283134). Risk assessment was performed using the Newcastle-Ottawa scale. Funnel plots were used to detect publication bias and asymmetry was assessed using Egger's tests. SOURCES: PubMed, Scopus, ScienceDirect, Cochrane, and additional sources were searched. STUDY SELECTION: Studies published until 10 December 2022. Clinical studies evaluating the success of root canal retreatment filled with gutta-percha with at least a 1-year follow-up were selected. RESULTS: Ten studies and one unpublished study fulfilled the inclusion criteria for quantitative analysis. The success rate of non-surgical root canal retreatment was 71% (95% CI: 66%-76%) with strict criteria and 87% (79% - 93%) with loose criteria for 1-3 years of follow-up, and 77% (66% - 86%) with strict criteria for a 4-5 years of follow-up. Endodontically retreated teeth with periapical lesions had a lower success rate under strict criteria. The tooth type, dental arch, initial periapical index (PAI) score, and the number of visits also affected the treatment success rate under strict criteria. For the loose criteria, teeth with larger periapical lesions and higher initial PAI scores had a lower success rate. CONCLUSIONS: According to the present systematic review and meta-analysis, non-surgical root canal retreatment results in favourable outcomes. The presence of a periapical radiolucency, periapical lesions >5mm, a higher initial PAI score, multiple-visit retreatments, and mandibular and molar teeth resulted in a lower success rate. CLINICAL SIGNIFICANCE: Non-surgical root canal retreatment filled with gutta-percha techniques is a relatively predictable procedure with a high success rate. Several variables can affect retreatment success, mainly the presence and size of a periapical lesion and the type of tooth.

Post-operative pain after single-visit root canal treatment using resin-based and bioceramic sealers in teeth with apical periodontitis: A randomised controlled-trial.

The present study aimed to compare postoperative pain in teeth with symptomatic and asymptomatic apical periodontitis (AP) following a single-visit endodontic treatment using BioRoot™ RCS or AH Plus at 8 h, 24 h and 48 h postoperatively. Postgraduate students performed endodontic treatment on 101 teeth with AP, randomised into two obturation groups. A 100-mm Visual Analog Scale was used to document the intensity of pain at preoperative, 8-h, 24-h and 48-h intervals. The Kolmogorov-Smirnov test was used for normality, and the median and interquartile ranges were compared using the Mann-Whitney U test. Preoperative pain (1.90 ± 3.50) was more frequent in teeth with symptomatic AP (p < 0.05). However, no significant differences were observed in postoperative pain at the 8-h, 24-h and 48-h intervals. Pre and postoperative pain were directly associated (p < 0.05). Single-visit root canal treatment in teeth with AP using both sealers resulted in similar levels of postoperative pain.

Outcome of Nonsurgical Root Canal Retreatment Procedures Obturated with Warm Gutta-percha Techniques: A Longitudinal Clinical Study.

INTRODUCTION: To evaluate the success rate of nonsurgical root canal retreatment at the 2-3-year follow-up and identify the possible prognostic factors. METHODS: Patients who underwent root canal retreatment at a university dental clinic were contacted for clinical and radiographic follow-up. The retreatment outcomes in these cases were based on clinical signs, symptoms, and radiographic criteria. Inter- and intraexaminer concordances were calculated using Cohen's kappa coefficient. The retreatment outcome was dichotomized into success or failure according to strict and loose criteria. The radiographic success criteria consisted of complete resolution or absence of a periapical lesion (strict criteria) or a reduction in the size of an existing periapical lesion at recall (loose criteria). χ2 tests were used to evaluate possible variables associated with retreatment outcomes (age, sex, tooth type, location, contact points, periapical status, quality of previous and final root canal filling, previous and final restoration, number of visits, and complications). RESULTS: Overall, 129 teeth (113 patients) were included in the final evaluation. The success rate was 80.6% under strict criteria and 93% under loose criteria. Molars, teeth with an initially higher periapical index score, and teeth with >5 mm periapical radiolucency had a lower success rate according to the strict criteria model (P < .05). When the loose success criteria were used, teeth with larger (>5 mm) periapical lesions and those that had been perforated during retreatment showed a lower success rate (P < .05). CONCLUSIONS: The present study demonstrated that nonsurgical root canal retreatment is a highly successful procedure after an observation period of 2-3 years. Treatment success is primarily affected by the presence of large periapical lesions.

Accuracy of CAD-CAM Surgically Guided Tooth Autotransplantation Using Guided Templates and Custom-designed Osteotomes in Human Cadaver Mandibles.

INTRODUCTION: A major challenge in dentistry is the replacement of teeth lost prematurely due to trauma, caries, or malformations; especially in growing patients. The aim of this study was to assess the accuracy of CAD-CAM surgically guided tooth autotransplantation in cryopreserved cadaver mandibles using guided templates and custom-designed osteotomes. METHODS: Cryopreserved human cadaver heads were digitized and scanned using an intraoral optical scanner and a large-volume cone beam computed tomography device. First, virtual surgical planning was performed to create a 3D tooth replica, 2 surgical guides, and a custom-made osteotome for each single-rooted tooth autotransplantation procedure/case. Surgical sockets were created in the selected mandibles using guided tooling consisting of an initial guided osteotomy with implant burs and a final guided osteotomy using custom osteotomes. After tooth autotransplantation, second large-volume cone beam computed tomography images of the 5 cadaver mandibles were obtained. The discrepancy in mm within the 3D space (apical and mesiodistal deviations) between the final position of the autotransplanted teeth and their digitally planned 3D initial position was calculated and analyzed statistically (P < .05). RESULTS: All donor teeth were placed without incident within their newly created sockets in the real mandibles. The mean difference between the digitally planned root apex position and the final tooth position was 2.46 ± 1.25 mm. The mesiodistal deviation of the autotransplanted teeth was 1.63 ± 0.96 mm. CONCLUSIONS: The autotransplantation of single-rooted teeth with custom-designed and 3D-printed surgical tooling provided promising results. The technique was able to create surgically prepared sockets that could accommodate transplanted teeth in mandibles.

Dental anxiety, cardiovascular changes and patient preconceptions toward implants and root canal treatments: An observational study.

Background: There is little information about dental anxiety and the patient's vital signs during dental procedures. This study evaluates and compare patient anxiety levels and cardiovascular changes before and during root canal treatment (RCT) and single-tooth implant procedures. Material and Methods: Preoperative data and pre-treatment considerations were recorded. HR and SpO2 were monitored during treatment procedures at five points. Data were analyzed accordingly using Mann Whitney or X2 tests. 80 patients met the inclusion criteria. Results: Anxiety and fear scores were strongly correlated (p< 0.001). Both treatments resulted in low levels of dental anxiety and fear. Patients with a prior dental bad experience presented higher anxiety scores in the implant treatment group (p< 0.05). Implant treatment was considered a more time-consuming and more painful procedure than root canal treatment (p< 0.05). No significant relation was found between the level of anxiety with HR and SpO2. Conclusions: No significant relation was found between the level of dental anxiety with HR and SpO2. Single-implant treatment was pre-considered to be a more time-consuming and more painful procedure when compared with a RCT. HR was higher at the initial stages and decreased as both procedures finished. Key words:Dental anxiety, endodontics, dental implants, oximetry, heart rate.

General Anxiety in Dental Staff and Hemodynamic Changes over Endodontists' Workday during the Coronavirus Disease 2019 Pandemic: A Prospective Longitudinal Study.

INTRODUCTION: The aim of this study was to assess general anxiety levels in endodontists and dental assistants related to different conditions during the pandemic and lockdown and to evaluate hemodynamic changes in endodontists' heart rate (HR), blood pressure, and blood oxygenation during their workday. METHODS: Anxiety levels in endodontists and dental assistants were recorded weekly during the state of alarm declared because of the coronavirus disease 2019 pandemic. Hemodynamic parameters were monitored using a sphygmomanometer for HR and blood pressure and a pulse oximeter for oxygen saturation. Measurements were taken before and after each root canal treatment as well as on arrival at the clinic and at the end of the working day. Rest data, recorded every Saturday, served as a control. Data analysis was performed using chi-square, paired t, Mann-Whitney, and analysis of variance tests (P < .05). RESULTS: General anxiety decreased over the weeks, with significant differences between weeks 1 and 4 (P < .05). Endodontists perceived higher anxiety levels of anxiety during anesthesia inoculation and dental assistants during the dental unit's disinfection and equipment material (P < .05). There was a significant increase in the cardiovascular response in all endodontists in the clinic registrations compared with rest data (P < .05). Values were higher in the strict confinement period and significant for HR when arriving at the clinic (P < .05). CONCLUSIONS: Levels of general anxiety were higher during the first weeks. The chief perceived factors related to anxiety in endodontists and dental assistants were the risk of contagion and protection measures. Higher HR and blood pressure levels were registered during the workday, especially when arriving at the clinic.

Dental Anxiety, Fear, and Root Canal Treatment Monitoring of Heart Rate and Oxygen Saturation in Patients Treated during the Coronavirus Disease 2019 Pandemic: An Observational Clinical Study.

INTRODUCTION: The present study aimed to evaluate anxiety in patients and to monitor their heart rate (HR) and blood oxygenation (SpO2) before, during, and after a root canal treatment (RCT) during the state of alarm in 2 different periods of strict and partial confinement. METHODS: The patients who required a primary RCT were selected. Demographic, preoperative, and postoperative variables were registered, including perceived dental anxiety, fear, HR, and SpO2. Spearman correlation, chi-square, Mann-Whitney, and Kruskal-Wallis tests were used for frequency distribution and variable interaction, and Wilcoxon and Mann-Whitney tests were used to compare HR and SpO2 between groups and different treatment points. RESULTS: Ninety-six patients were included. The median Modified Dental Anxiety Scale scores were 8 (interquartile range [IQR], 6-9.25) and 6 (IQR, 5.5-8) in patients treated during the strict and partial confinement periods. The median fear scores were 2 (IQR, 0-5) and 3 (IQR, 1-5), respectively. Having a previous dental bad experience resulted in higher dental anxiety and fear (P < .05). HR was increased in patients with higher MDAS and fear scores and in those treated during the strict confinement (P < .05). In treatment time points T6 (x-ray taking), and T7 (post-treatment), HR decreased compared with the other evaluated treatment time points (P < .05). No clinical differences were found regarding SpO2. CONCLUSIONS: Self-perception on dental anxiety and fear was similar to other studies in a nonpandemic context. Patients with higher levels of dental anxiety and those treated in the strict confinement period presented an elevated HR. However, it can be stated that RCT performed by endodontists does not result in a significant alteration in patients.

Micro-computed Tomographic Assessment and Comparative Study of the Shaping Ability of 6 Nickel-Titanium Files: An In Vitro Study.

INTRODUCTION: This research studies and compares the shaping ability of WaveOne Gold (WG; Dentsply Tulsa Dental Specialties, Tulsa, OK), the Reciproc Blue (RB; VDW, Munich, Germany), TRUShape (TS, Dentsply Tulsa Dental Specialties), XP-endo Shaper (XP; FKG, La Chaux-de-Fonds, Switzerland), iRace (IR, FKG), and TruNatomy (TN; Dentsply Sirona, Ballaigues, Switzerland) in the preparation of moderately curved canals and using micro-computed tomographic technology. METHODS: Sixty lower molars with 2 mesial canals were randomly distributed into 6 groups of 10 molars and 20 canals per group (n = 20). Specimens were scanned before and after preparation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WG, group 2 with RB, group 3 with TS, group 4 with XP, group 5 with IR, and group 6 with TN. After instrumentation, researchers quantified the changes produced in the canal geometry in terms of surface, volume, structure thickness, surface convexity index, structure model index, percentage of surface touched, and centroids. Wilcoxon and analysis of variance tests were performed to compare the values before and after preparation and the differences between groups. The significance level was established at 5%. RESULTS: There were no significant differences between WG and RB (P > .05) and between TN and XP (P > .05). TN had significant differences with WG, RB, TS, and IR (P < .05). All the files produced similar apical transportation (P > .05). CONCLUSIONS: WG and RB and TN and XP had similar shaping effectivity. TS and WG touched the highest percentages of canal surfaces (81% and 73%, respectively) but produced the biggest changes in the canal anatomy. TN and XP better kept the canal anatomy, but TN touched the lowest percentage of canal surface (50%). All the files used were able to clean and to shape moderately curved canals with minimal apical transportation.

Outcome and Survival of Endodontically Treated Cracked Posterior Permanent Teeth: A Systematic Review and Meta-analysis.

INTRODUCTION: The aim of the present systematic review and meta-analysis was to evaluate the success and survival rate of endodontically treated cracked posterior teeth and to assess the preoperative factors that affect teeth survival. METHODS: The study protocol was registered on the PROSPERO international prospective database of systematic reviews (CRD42019119091). Electronic search was performed for studies up to November 30, 2018 in the following databases: PubMed, Scopus, and Cochrane. All searches were done following the PRISMA guidelines. Clinical studies evaluating the success and/or the survival rate of cracked teeth that were endodontically treated with at least 1-year follow-up were selected. The Newcastle-Ottawa scale was used to evaluate risk assessment. Publication bias was evaluated with funnel plots, and the Egger's test was performed to test asymmetry. RESULTS: From the 410 studies identified through the initial search, 7 studies qualified for the final analysis, all of which were longitudinal cohort studies. The results of the meta-analysis indicated a survival rate of 88% (confidence interval, 0.81-0.94) and a success rate of 82% (confidence interval, 0.78-0.86) after 1 year of follow-up. The presence of a periodontal pocket associated to a crack (relative risk, 1.11) resulted in a higher risk of tooth loss. Patient sex, tooth type, position, the number of cracks present, and preoperative pulp status did not affect treatment survival rate (P > .05). Most of the included studies did not have an accurate record of many variables that could affect the tooth survival. Plus, studies did not present extended follow-up periods or an adequate dropout rate to properly assess treatment outcome and survival. CONCLUSIONS: According to the results of the present systematic review and meta-analysis, root canal treatment in cracked posterior teeth can be considered a suitable treatment option. The presence of an associated periodontal pocket results in a lower survival rate.

Outcome of Partial Pulpotomy in Cariously Exposed Posterior Permanent Teeth: A Systematic Review and Meta-analysis.

INTRODUCTION: The current systematic review and meta-analysis aimed to evaluate the success rate of partial pulpotomy in treating permanent posterior teeth with carious vital pulp exposure. A secondary aim was to assess the prognostic factors using a meta-regression. METHODS: An electronic search was performed for studies from January 1950 to November 2018 in the following databases: PubMed, ScienceDirect, and Cochrane. All searches were performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Clinical studies evaluating the success rate of cariously exposed vital human permanent posterior teeth treated with a partial pulpotomy were selected. Only randomized clinical trials and prospective clinical studies were included for evaluation. The Newcastle-Ottawa Scale and the Cochrane Collaboration's tool were used to evaluate risk assessment. RESULTS: From the 218 studies identified through the initial search, 11 studies qualified for the final analysis (5 randomized clinical trials and 6 prospective studies). The results of the meta-analysis indicate a success rate of 98% (confidence interval [CI]: 0.94-1), 96% (CI: 0.92-0.99), and 92% (CI: 0.83-0.97) after 6 months and 1 and 2 years of follow-up. Examining the probable prognostic factors using meta-regression analysis, only preoperative pulp status (P = .001) was identified as a significant factor, with studies including teeth with the presumptive diagnosis of irreversible pulpitis displaying significantly lower results. The final solution, pulp capping material, apex closure, and the age of the patient did not affect the treatment success rate (P > .05). CONCLUSIONS: The available data suggest that a partial pulpotomy results in high success rates in treating cariously exposed permanent posterior teeth up to 2 years. Six months of monitoring can be considered an appropriate period when evaluating the success of a partial pulpotomy although more clinical and radiographic controls are essential to ensuring success.

Canal Transportation and Centering Ability in Long Oval Canals: A Multidimentional Analysis.

INTRODUCTION: The purpose of this study was to evaluate and compare the centering ability and canal transportation of the ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) and Self-adjusting File (SAF; ReDent-Nova, Ra'anana, Israel) systems in long oval root canals using cone-beam computed tomography imaging. METHODS: Fifty-six fully formed single-rooted mandibular premolars were selected with a buccolingual canal size 2 to 2.5 times the mesiodistal size at 5 mm from the apex, ranging from a 0°-10° canal curvature with a 5- to 6-mm radius. The teeth were divided into 2 groups (n = 28) and prepared with PTN or SAF according to the manufacturers' instructions. Cone-beam computed tomographic images were taken in the same position before and after instrumentation using modeling wax. The centering ability and canal transportation were calculated at 3, 6, and 9 mm from the apex in both mesiodistal and buccolingual directions. The mean and standard deviation were calculated, and the Student t test was used for comparative analysis. RESULTS: significant difference for canal transportation was observed mesiodistally at 9 mm from the apex (P < .05) where the PTN shaved more dentin in 1 direction. A significant difference for the centering ability was observed at 6 mm buccolingually from the apex (P < .05) where the PTN was less centered in the canal compared with the SAF. CONCLUSIONS: Both SAF and PTN were shown to be safe for being used in long oval canals. SAF resulted in less transportation at the coronal third in the mesiodistal direction and more centered at the middle third in the buccolingual direction compared with PTN.

Root Dentine Thickness and Concavity Depth in Mandibular Molars: A Cone Beam Computed Tomography Population Study.

OBJECTIVE: The purposes of the present study were to evaluate dentine thickness and concavity depth below the furcation level of the mesial canals of the mandibular first and second molars, to examine differences between gender, age, and quadrant, and to prove if there is a relationship between root length and dentine thickness. METHODS: Two hundred eleven mandibular first and second molars were included in this study. Samples were divided according to age, gender, quadrant, and root length. Measurements of dentine thickness from the external border of the root canal to the external root surface and concavity depth were recorded 1, 2, and 4 mm below the furcation level. Kruskal-Wallis and Wilcoxon rank sum tests were performed to estimate the influence of different variables, and a multiple regression analysis was performed to evaluate the influence of dentine thickness below the furcation level. RESULTS: First molars had a deeper concavity depth with significant differences in both 1 mm and 2 mm levels than second molars (P<0.05). According to concavity depth, there was no relationship with teeth length (P>0.05). The distal concavity was significantly deeper in the 1 and 2 mm levels (P<0.05). According to gender, the female group had a reduced dentine thickness in both mesiolingual and mesiobuccal canals in both 1 mm and 2 mm levels (P<0.05). CONCLUSION: Female patients have a reduced dentine thickness below the furcation level. In order to select the most appropriate instrumentation procedure in every specific case, clinicians must be aware of the dentine reduced thickness measurements to avoid procedural iatrogenic damage.

Development of Periapical Lesions in Endodontically Treated Teeth with and without Periodontal Involvement: A Retrospective Cohort Study.

INTRODUCTION: The purpose of this study was to investigate the incidence of apical periodontitis (AP) in endodontically treated teeth with and without periodontal involvement. METHODS: The records of 602 patients with 775 root canal-treated teeth were initially examined. Only teeth with adequate root canal filling, adequate coronal restoration, and no AP (periapical index = 1) were selected for further investigation. A total of 194 teeth were included in this cohort study. Age, sex, history of diabetes mellitus, smoking, hypertension, and immunodeficiency disorders were recorded. Two groups were made according to the periodontal status of the patients. The control group included periodontally healthy patients and the periodontal group patients with periodontal disease receiving nonsurgical periodontal treatment. After an observation period of at least 2 years, the incidence of AP was scored using the periapical index. The relationship between patients' variables and AP was conducted using the Cohen kappa test, the chi-square test, odds ratio (OR), and logistic regression analysis. RESULTS: Newly emerged AP was found in 14% of periodontally involved teeth and in 3% of nonperiodontal involved teeth (P < .05, OR = 5.19, 95% confidence interval). The periodontal condition and hypertension were the only significant factors associated with the presence of AP in the follow-up after univariate logistic regression. Adjusting for hypertension, multivariate logistic regressions showed that periodontal status remained significant (OR = 5.25, 95% CI, P < .05). CONCLUSIONS: The risk of developing AP in endodontically treated teeth is 5.19 times higher for patients with periodontal disease compared with patients without periodontal disease.

Comparison of postoperative pain after root canal treatment using reciprocating instruments based on operator's experience: A prospective clinical study.

BACKGROUND: The aim of the present study was to compare clinically the incidence of postoperative pain after endodontic treatment using the Reciproc System, taking into account the operator's experience. MATERIAL AND METHODS: One hundred patients scheduled for routine endodontic treatment were enrolled in this study. Endodontic treatment was carried out in a single visit by undergraduate and postgraduate students. The chemomechanical preparation of root canals was performed with Reciproc instruments. Pretreatment and postoperative pain was recorded using a visual analogue scale (VAS). Postoperative pain and the need for analgesic consumption were assessed at 4, 8, 16, 24, 48 and 72 hours post-treatment. The data were analyzed using the Mann-Whitney U and Chi-Square test, and the significance was set at P<0.05. RESULTS: The mean value of pain after root canal treatment was 1.13±1.94 and 1.91±2.07 on a VAS between 0 and 10 in treatments performed by undergraduate and postgraduate students, respectively. There was a significant difference in the incidence of postoperative pain between the two groups (P<0.05). CONCLUSIONS: The prevalence of postoperative pain was high in the treatments performed by postgraduate students in comparison with undergraduate students. This suggests that operator experience has an influence on the prevalence of postoperative pain after root canal treatment. Key words:Post-endodontic pain, root canal treatment, reciprocating systems, Expert operators Inexperienced operators.

Effect of manual dynamic activation with citric acid solutions in smear layer removal: A scanning electron microscopic evaluation.

BACKGROUND/PURPOSE: Chelating agents have been used for the removal of the smear layer on teeth. However, due to inadequate volume and/or penetration of the solutions during irrigation, smear layer removal is less effective in the apical third. The purpose of this study was to compare the efficacy of three chelating solutions with and without manual dynamic irrigation in smear layer removal. MATERIALS AND METHODS: Sixty-six single-root canal teeth were decoronated, instrumented, and divided into six experimental groups (n = 10) and two control groups (n = 3). The groups received a final rinse with 1 mL of 17% EDTA and 5% or 10% citric acid (CA) for 1 minute, with or without manual dynamic activation, followed by a final 3-mL rinse with 4.2% NaOCl (5 minutes). The teeth were then longitudinally split and prepared for environmental scanning electron microscopy analysis. Digital images (500×) were taken for smear layer removal evaluation at 2 mm, 6 mm, and 10 mm from the working length. RESULTS: The most effective smear layer removal occurred with 5% and 10% CA combined with manual dynamic activation (Groups 7 and 8), where significant differences were observed when compared with the EDTA groups (Groups 2 and 6; P < 0.05). We found no significant differences between manual dynamic activation with 5% and 10% CA (Groups 7 and 8) in smear layer or debris removal (P > 0.05). CONCLUSION: Manual dynamic activation of CA improves smear layer removal, and a reduction in CA concentration to 5% does not compromise smear layer removal in comparison with higher concentrations.

Influence of preoperative pain intensity on postoperative pain after root canal treatment: A prospective clinical study.

OBJECTIVES: The aim of this prospective study was to investigate the correlation between the intensity of preoperative pain and the presence of postoperative pain, taking into account the variables sex, tooth type, arch, and tooth vitality. METHODS: Two hundred and seventy patients with pulpal pathology who were scheduled for routine endodontic treatment were enrolled in this study. Conventional endodontic treatment was carried out in a single visit. The chemomechanical preparation of root canals was performed with ProTaper instruments, and canals were obturated with a warm gutta-percha obturation technique. A structured questionnaire was used to record data on sex, age, type of tooth, location and pulp diagnosis. Patients were asked to record their preoperative and postoperative pain using a 10-cm visual analogue scale (VAS). Postoperative pain and the need for analgesic consumption were assessed at 4, 8, 16, 24, 48 and 72h post-treatment. The data were analyzed using the Mann-Whitney U and chi-square test, and the significance was set at P<.05. RESULTS: The mean level of pain after root canal treatment was 2.58±2.80 on a VAS between 0 and 10. Variables that were associated with a higher preoperative pain intensity (female, mandible and molar) also had a higher value of postoperative pain (P>.05). CONCLUSIONS: Within the limitations of this study, it can be concluded that the presence of preoperative pain is the variable that most influences the prevalence of postoperative pain. CLINICAL SIGNIFICANCE: Pain management should be an integral part of dental treatment. The present study analyses the incidence of postoperative pain that should be expected by patients with different intensity of pain before root canal treatment.

In vitro comparison in a manikin model: increasing apical enlargement with K3 and K3XF rotary instruments.

INTRODUCTION: The aim of the study was to compare the K3 and K3XF systems (SybronEndo, Glendora, CA) after 1 and 2 uses by evaluating apical transportation, working length loss, and working time in a manikin model. METHODS: Mesial canals of 40 extracted first mandibular molars were instrumented. Radiographs taken after instrumentation with #25, #30, #35, and #40 files were superimposed on the preoperative image in both mesiodistal and buccolingual angulations. AutoCAD (Autodesk Inc, San Rafael, CA) was used to measure working length loss and apical transportation at 0, 0.5, and 1 mm from the working length (WL). The working time was measured. Group comparison was analyzed using post hoc Tukey honestly significant difference tests (P < .05). RESULTS: No significant differences were found in apical transportation, working length loss between K3 and K3XF systems, or between the number of uses. Significant differences were found when canal enlargement was performed to a #35-40 (P < .05). K3 instrumentation performed significantly faster (29.6 ± 15.4) than with the K3XF system (40.2 ± 17.7) (P < .05). No differences were observed in working time when comparing the number of uses. CONCLUSIONS: K3 and R-phase K3XF rotary systems shaped curved root canals safely with minimal apical transportation, even up to a 40/04 file.

A comparison of apical transportation between FlexMaster and Twisted Files rotary instruments.

INTRODUCTION: The aim of this study was to evaluate apical transportation in root canals after the use of Twisted Files (TF; SybronEndo, Orange, CA) and FlexMaster (VDW, Munich, Germany) #40/04 rotary files. METHODS: A double-digital radiographic technique was used to compare apical transportation between the TF and FlexMaster systems. Each rotary system was used to instrument mesial canals from 80 extracted mandibular molars. The central axes of the file imaged before instrumentation (#15 K-file) and the master apical rotary file (#40/04) were superimposed digitally. AutoCAD 2008 (Autodesk Inc, San Rafael, CA) was used to measure apical transportation at 0.5 mm from the working length (WL). The data were analyzed using the Student's t test, and significance was set at P < .05. RESULTS: The mean amount of apical transportation at 0.5 mm from the WL was 0.17 ± 0.09 mm for the FlexMaster group and 0.19 ± 0.12 mm for the TF group. No statistically significant differences in apical transportation were found between the 2 groups. CONCLUSIONS: Under the conditions of the study, no statistically significant differences in apical transportation were observed between FlexMaster and TF rotary files.