Current status of cone-beam computed tomography teaching in Brazilian undergraduate endodontic programs - A web-based survey.

PURPOSES: This study aimed to assess the current status of cone-beam computed tomography (CBCT) education in Brazilian undergraduate Endodontic programs. METHODS: One hundred program directors were emailed. The questionnaire asked whether the CBCT topic was included in the program, the availability of a CBCT machine, and, the total length of the dental program. For the group that does not teach, seven questions discussed the reasons for not teaching and whether another subject included this topic. For the programs that included CBCT, seven questions discussed the number of hours included, and the impression of the program directors with the quality of the teaching. The chi-square test was used for the correlation between the availability of the CBCT machine and the length of the dental program with the inclusion of the topic. RESULTS: Thirty-five program directors replied to the questionnaire. Twenty-six (74.3%) reported that the topic of CBCT is not included in their programs. There was no impact of the availability of a CBCT machine on the inclusion of the topic (p > 0.05). The increased length of the dental program decreased the inclusion of the topic (p < 0.05). Fifty percent of the directors replied that lack of time is the reason for not including the topic. Among the programs that include CBCT, the majority (55.6%) deliver 3-5 h of lectures. The practical activities range from 1 to 5 h or more. The majority (77.8%) of the directors are satisfied with the content delivered and 44.4% understand that the students are competent in the interpretation of CBCT images. CONCLUSIONS: The majority of the Endodontic undergraduate programs in Brazil do not include CBCT in the program. The availability of a CBCT machine does not impact the inclusion of the topic, the increased duration of the dental program decreases the inclusion of the CBCT topic.

Influence of different working lengths on the shaping ability of Reciproc Blue in the apical third and apical foramen: a micro-computed tomographic study

Aim: This study aimed to assess the shaping ability of Reciproc Blue in the apical third and apical foramen of moderately curved canals at different working lengths (WLs), by micro-computed tomography. Methods: Thirty-six mesial roots (mesiobuccal and mesiolingual canals) were included, each with 2 separate root canals and independent apical foramina, according to type IV of Vertucci's classification of first and second mandibular molars. The canals were instrumented at three different WLs: G-1, 1mm short of the major apical foramen; G0, at the major apical foramen; G+1, 1mm beyond the major apical foramen. The groups were assessed for changes in root canal volume and untouched wall area in the apical third. Groups G0 and G+1 were also compared for percentage of untouched walls at the apical foramen. One-way ANOVA (post hoc Tukey test) and Student's t-test adopted a 5% level of significance. Results: Root canal volumes (mm3) in the apical third were 22.86±10.46, 44.48±24.91, and 55.71±21.32 in G-1, G0 and G+1, respectively. G-1 volume following instrumentation increased significantly less than that of G0 or G+1 (P>.05); G0 did not differ from G+1. The percentage of untouched wall area in the apical third did not differ among the three groups (P>.05). G0 and G+1 did not differ regarding untouched walls in the major apical foramem walls. Conclusion: Extending the WL from 1mm short of the apical foramen to a point at and beyond the WL increases the apical third volume without increasing the prepared area. Untouched surface areas of the apical foramen were not modified by instrumentation at or beyond the foramen

Reciprocating Kinematics of X-Smart Plus, VDW Silver and, iRoot Endodontic Motors: A Comparison Between Real and Set Values.

This study assessed 3 endodontic motors, X-Smart Plus (Dentsply Sirona, Ballaigues, Switzerland), VDW.Silver Reciproc (VDW GmbH, München, Germany) and, iRoot (Bassi Endodontics, Belo Horizonte, Brazil) in 2 different reciprocating settings. The movements evaluated were 170° in counter-clockwise (CCW) and 50° in clockwise (CW) at 350 RPM, and 150° CCW and 30° CW at 300 RPM. For the X-Smart Plus and VDW Silver the settings used were the ones in the motor library. For the iRoot, the motor was adjusted to the angles of the study. A customized optic target was attached to the contra-angle of the motor and the movements were recorded with a high-resolution camera (K2 DistaMaxTM Long-Distance Microscope System, Infinity Photo-Optical Company, Colorado, EUA) at 2,400 frames per second (FPS). The images were analyzed with the Vision Research software (Inc. Headquarters, Wayne, New Jersey, EUA). The following kinematic parameters were assessed: CCW angle, CW angle, speed (RPM) at both directions, and, standstill time at each change of directions. The Intraclass Correlation Coefficient (ICC) and Kruskal-Wallis (method of Dunn) were used at a significant level of 5%. There was no statistically significant difference among the motors at the 150°/30° setting (P > .05); the iRoot was the least reliable at the 170°/50° setting for CCW angle, speed, and net angle parameters (P < 0.05). The standstill time of all motors in both directions was identical. None of the motors were able to reproduce faithfully the set movements. The iRoot motor presented a higher discrepancy when compared to X-Smart and VDW Silver.

Apical periodontitis in mesiobuccal roots of maxillary molars: influence of anatomy and quality of root canal treatment, a CBCT study.

Objectives: This study aimed to evaluate the prevalence of apical periodontitis (AP) in the mesiobuccal roots of root canal-treated maxillary molars. Materials and Methods: One thousand cone-beam computed tomography images of the teeth were examined by 2 dental specialists in oral radiology and endodontics. The internal anatomy of the roots, Vertucci's classification, quality of root canal treatment, and presence of missed canals were evaluated; additionally, the correlation between these variables and AP was ascertained. Results: A total of 1,000 roots (692 first molars and 308 second molars) encompassing 1,549 canals were assessed, and the quality of the root canal filling in the majority (56.9%) of the canals was satisfactory. AP was observed in 54.4% of the teeth. A mesiolingual canal in the mesiobuccal root (MB2 canal) was observed in 54.9% of the images, and the majority (83.5%) of these canals were not filled. Significant associations were observed between the presence of an MB2 canal and the quality of the root canal filling and the presence of AP. Conclusions: AP was detected in more than half of the images. The MB2 canals were frequently missed or poorly filled.

Reciprocating Kinematics of X-Smart Plus, VDW Silver and, iRoot Endodontic Motors: A Comparison Between Real and Set Values

Abstract This study assessed 3 endodontic motors, X-Smart Plus (Dentsply Sirona, Ballaigues, Switzerland), VDW.Silver Reciproc (VDW GmbH, München, Germany) and, iRoot (Bassi Endodontics, Belo Horizonte, Brazil) in 2 different reciprocating settings. The movements evaluated were 170° in counter-clockwise (CCW) and 50° in clockwise (CW) at 350 RPM, and 150° CCW and 30° CW at 300 RPM. For the X-Smart Plus and VDW Silver the settings used were the ones in the motor library. For the iRoot, the motor was adjusted to the angles of the study. A customized optic target was attached to the contra-angle of the motor and the movements were recorded with a high-resolution camera (K2 DistaMaxTM Long-Distance Microscope System, Infinity Photo-Optical Company, Colorado, EUA) at 2,400 frames per second (FPS). The images were analyzed with the Vision Research software (Inc. Headquarters, Wayne, New Jersey, EUA). The following kinematic parameters were assessed: CCW angle, CW angle, speed (RPM) at both directions, and, standstill time at each change of directions. The Intraclass Correlation Coefficient (ICC) and Kruskal-Wallis (method of Dunn) were used at a significant level of 5%. There was no statistically significant difference among the motors at the 150°/30° setting (P > .05); the iRoot was the least reliable at the 170°/50° setting for CCW angle, speed, and net angle parameters (P < 0.05). The standstill time of all motors in both directions was identical. None of the motors were able to reproduce faithfully the set movements. The iRoot motor presented a higher discrepancy when compared to X-Smart and VDW Silver.

Resumo Este estudo avaliou 3 motores endodônticos, X-Smart Plus (Dentsply Sirona, Ballaigues, Suíça), VDW.Silver Reciproc (VDW GmbH, Munique, Alemanha) e iRoot (Bassi Endodontics, Belo Horizonte, Brasil) em 2 diferentes ajustes de movimento reciprocante. Os movimentos analisados foram: 170° em sentido anti-horário (CCW) e 50° em sentido horário (CW) a 350 RPM, e 150° CCW e 30° CW a 300 RPM. Para os motores X-Smart Plus e VDW Silver os ajustes usados foram os que se apresentam nos ajustes pré-definidos dos motores. Para o iRoot o motor foi ajustado para os ângulos do estudo. Um alvo ótico customizado foi preso ao contra ângulo do motor e os movimentos foram gravados com uma câmara de alto resolução (K2 DistaMaxTM Long-Distance Microscope System, Infinity Photo-Optical Company, Colorado, EUA) a 2.400 quadros por segundo (FPS). As imagens foram analisadas com o sotware Vision Research (Inc. Headquarters, Wayne, Nova Jersey, USA). Os seguintes parâmetros de cinemática foram avaliados: ângulo anti-horário, ângulo horário, ângulo líquido, velocidade (RPM) em ambas direções e tempo de parada a cada mudança de direção. O Coeficiente de Correlação Intraclasse (ICC) e o teste de Kruskal-Wallis (método de Dunn) foram usados com nível de significâncias de 5%. Não houve diferença estatisticamente significante entre os motores no ajuste de 150°/30° (P > .05); o motor iRoot foi o menos confiável no ajuste de 170°/50° para o ângulo anti-horário, velocidade e ângulo líquido (P < 0.05). O tempo de parada em todos os motores foi idêntico em ambas as direções. Nenhum dos motores foi capaz de reproduzir fielmente os movimentos. O motor iRoot apresentou maior discrepância quando comparado com o X-Smart Plus e VDW Silver.

The impact of dental care intervention on ventilator-associate events: A Quasi-experimental study.

BACKGROUND: This study aimed to evaluate a multidisciplinary intensive oral health protocol, proposed and applied by a dentist, in an adult Intensive Care Unit (ICU), in regards to the prevention of Ventilator-associated Pneumonia (VAP), compared with retrospective data. METHODS: 4,103 patients admitted to the adult ICU from January 2013 to December 2017 and selected patients who were under mechanical ventilation with an orotracheal tube for at least 48 hours. These patients were compared before (Baseline Group) and after (Intervention Group) the hygiene protocol established and carried out by a multidisciplinary team led by a dentist. The Baseline Group, from January 2013 to May 2015, 213 patients, and the Intervention Group, from June 2015 to December 2017, 137 patients. RESULTS: Forty-five patients (21.12%) in the Baseline Group and 5 patients (3.65%) in the Intervention Group developed VAP (P < .05). Twenty-two patients (10.33%) died due to VAP in the Baseline Group, and 1 patient (0.73%) died due to VAP (P < .05) in the Intervention Group. The mortality rate of  VAP was 48.89% for Baseline Group and 20.00% for Intervention Group (P > .05). CONCLUSIONS: The study showed better outcomes when patients' oral health is led, evaluated and treated by a dentist in the ICU. The dental care intervention contributed to the reduction of VAP episodes and deaths due to VAP.

Effect of Photodynamic Therapy on Postoperative Pain in Posterior Teeth with Symptomatic Apical Periodontitis.

This study aimed to evaluate the impact of photodynamic therapy (PDT) after root canal preparation on pain relief in posterior teeth presenting with symptomatic apical periodontitis (SAP). A visual analog scale (VAS) was completed by the patients which registered their pain perception as none (0), mild (1-3), moderate (4-7), or severe (8-10). Only patients who registered moderate or severe pain were included. Seventy patients were allocated to two groups (n=35): a control group (CG) without the PDT application and an intervention group with PDT application (PG). The same chemo-mechanical preparation was achieved in both groups. In the PG, 150 µM methylene blue (MB)Please remove the underline was placed inside the canal for 2 minutes and a 660 nm wavelength laser was applied through a fiber for 3 minutes (100 mW, 600 J/cm², total 18J). The patients were asked to register their pain perception in the VAS document after 24-h, 72-h, and 1-week intervals. The number of tablets taken for pain relief was also recorded. The Mann-Whitney, Students T-test and Fisher´s exact tests were used for statistical analysis (P < .05). After 1 week, 32 patients in the CG and 33 in the PG returned their VAS cards. The PG resulted in lower pain levels after the 24-hour interval (median 0) than the CG (median 2); there was no difference between both groups at 72-h and 1-week intervals. The decrease in pain was higher in the PG at all time-intervals when compared to the CG. There was no difference in the mean number of tablets taken for pain relief (P > .05). Within the limitations of this study, it can be concluded that PDT was efficient in decreasing pain in teeth presenting with SAP. There was no difference observed after 72 hours and there was no impact on the intake of pain relief medication.

The antimicrobial effect of different ozone protocols applied in severe curved canals contaminated with Enterococcus faecalis: ex vivo study.

The aim of this study was to evaluate 3 different irrigation protocols using ozone on monoculture biofilm of Enterococcus faecalis. Fifty disto-buccal roots of maxillary first molars were instrumented up to the size 25.08, sterilized and then incubated with Enterococcus faecalis for 21 days for biofilm maturation in the root canal walls. After contamination, the initial collection (S1) was performed and the 50 samples were divided in 3 experimental groups (n = 15) and 1 positive control group (n = 5) as follows: Group1: Ozonated water (40 µg/ml); Group2: gaseous ozone (40 µg/ml); Group3: Ozonated water (40 µg/ml) under continuous ultrasonic irrigation (CUI) and, Group 4: 2.5% sodium hypochlorite (positive control). The final collection (S2) was performed using hedstroem files # 25 by scraping the root canal wall and absorbed paper cone. The collected samples were analyzed by CFU/ml count and qPCR. To compare the effect of irrigation methods and to investigate E. faecalis count data, Kruskal-Wallis and Wilcoxon nonparametric tests were used at p < 05. The values of the differences between the S1 values and the S2 values revealed that the groups did not differ significantly for either E. faecalis CFU count data (p = 0.713) or q-PCR (p = 0.185), however, it is observed that for all groups, the CFU count of E. faecalis decreased over 99%. For the q-PCR assay, the reduction was on the order of 74-95%. Only the NaOCl positive control group presented total elimination of CFU/mL bacterial counting. The ozone protocols assessed were similar in regard to Enterococcus faecalis reduction.

Success, Survival Rate, and Soft Tissue Esthetic of Tooth Autotransplantation.

INTRODUCTION: The aim of this retrospective study was to assess the success, survival rate, and soft tissue esthetic of autotransplanted teeth. METHODS: This study included patients with at least 1 tooth autotransplanted to the maxilla during childhood or adolescence. The autotransplantation technique included the removal of an immature tooth from a donor site and its placement in the maxilla as a replacement for a missing or extremely compromised tooth. The cases were properly restored to ensure function and esthetic. To be considered successful, the tooth should be asymptomatic at the time of assessment, no pain to palpation and percussion, have no signs of apical periodontitis or a sinus tract, have a periodontal probe ≤3, and have an absence of root resorption and development of at least 70% of the normal root. The esthetic evaluation of the soft tissue was based on the pink esthetic score and graded as very unsatisfactory, unsatisfactory, poor, fair, good, or excellent. Data were statistically analyzed at a significance level of 5%. RESULTS: Thirty-five patients (23 males and 12 females) had 43 anterior teeth replaced, including 42 central incisors and 1 lateral incisor. The follow-up period ranged from 1-25 years. In regard to success and the survival rate, 43 teeth were assessed; 34 cases (79.07%) were considered successful and 9 (20.93%) unsuccessful. Only 1 tooth was lost, and 42 teeth remained functional (survival rate = 97.67%). In regard to the esthetic, 40 teeth could be assessed and were considered as excellent (30%), good (35%), fair (27.5%), and poor (7.5%); there were no reports of unsatisfactory or very unsatisfactory cases. CONCLUSIONS: Tooth autotransplantation can be considered a valid procedure to replace lost teeth in the maxilla, presenting high survival and success rates. The overall esthetic of the patients was considered as satisfactory.

Assessment of Extrusion and Postoperative Pain of a Bioceramic and Resin-Based Root Canal Sealer.

OBJECTIVES: The objective of this study was to compare a bioceramic and a resin-based endodontic sealer with regard to extrusion and postoperative pain. MATERIALS AND METHODS: Sixty-four patients requiring endodontic treatment of single-rooted maxillary teeth with necrotic pulps were included in this study. The root canal treatments were performed in a single visit using a size 40.06 single-file reciprocating system under 2.5% NaOCl irrigation. After irrigation with 17% ethylenediaminetetraacetic acid (EDTA) and 2.5% NaOCl, the canals were dried and randomly divided into two different groups (n = 32) depending on the sealer used: resin-based group (RG) in which the canals were filled with the AH Plus, and the bioceramic group (BG) in which the canals were filled with the Sealer Plus BC. Ibuprofen (600 mg) was prescribed every 6 hours if the volunteers experienced pain. The patients registered their pain sensation in a visual analog scale (VAS) card, ranging from 0 to 10 at 24-hour, 48-hour, 72-hour, and 1-week intervals. STATISTICAL ANALYSIS: For statistical analysis, the level of significance was set at p < 0.05. RESULTS: Sealer extrusion occurred in nine patients of the RG and in 19 patients of the BG (p < 0.05). The average pain level at 24-hour and 48-hour intervals was, respectively, 1.46 ± 1.96 and 0.44 ± 0.86 for RG, and 1.21 ± 2.09 and 0.09 ± 0.38 for BG. There was no report of pain after 48 hours. The mean number of tablets taken for pain relief was 0.03 ± 0.17 for RG and 0.06 ± 0.24 for BG. No statistically significant difference was found with regard to pain level and intake of pain killer tablets (p > 0.05). CONCLUSIONS: The BG sealer presented significantly more extrusion than the RG sealer. Sealer extrusion was not associated with pain. The average pain level and the mean number of tablets taken for pain relief were similar in both groups.

The effects of photodynamic therapy on postoperative pain in teeth with necrotic pulps.

This study aimed to determine the effects of photodynamic therapy (PDT) on postoperative pain after treatments of teeth with necrotic pulps. This randomized clinical trial consisted of 60 patients who presented for treatment of asymptomatic teeth. The patients were randomly assigned into the Control Group (CG) or the PDT Group (PG). The canals were instrumented with a reciprocating instrument (50.05) under 2.5% NaOCL irrigation. After instrumentation was completed, the canals were flooded with 1.56 µM/mL of methylene blue (MB), the optical fiber was inserted to the working length and applied for 3 min (P =100 mW, t =3 min, E = 18 J). The device emitted PDT only for the PG. The operator and the patient were both masked to the treatment protocol. After PDT, the root canal treatment was completed and the canals were filled. A card was given to the patients to document their pain perception through the 0-10 visual analogue scale (VAS) at 24 h, 72 h, and 1-week intervals. The Mann-Whitney and Fisher´s exact tests were used for statistical analysis (P < .05). The average pain level for the CG was 1.33 at 24 -hs and 0.50 at 72 -hs; for the PG, the average pain level was 0.37 at 24 -h and 0 at 72 -h (P < .05). After 1-week there was no report of pain. PDT had a significant effect in decreasing postoperative pain at 24- and 72 -h intervals in treatment of single-rooted teeth with necrotic pulps performed in one visit.

Root Anatomy and Canal Configuration of Maxillary Molars in a Brazilian Subpopulation: A 125-µm Cone-Beam Computed Tomographic Study.

OBJECTIVE: Knowledge of internal anatomy of the teeth is of great importance in endodontics, leading to success in root canal therapy (RCT). The aim of this study was to assess the root anatomy and canal configuration of maxillary molars in a Brazilian subpopulation using tomographic images using a voxel size of 125 µm. MATERIALS AND METHODS: This in vivo retrospective study assessed 651 cone-beam computed tomographic scans from 328 maxillary first molars and 323 maxillary second molars. The images were assessed by two endodontists and an oral radiologist. Only permanent molars with fully developed roots and with no signs of RCT were included. RESULTS: Maxillary first and second molars presented three separated roots in 99.39 and 90.09% of the cases, respectively. The presence of mesiolingual canals in the mesiobuccal roots was 64.22% for maxillary first molars and 33.56% for maxillary second molars. Distobuccal canals in the maxillary first and second molars presented Vertucci's Type I configuration in 99.39 and 99.66%, respectively, and palatal canals in the maxillary first and second molars presented Vertucci's Type I configuration in 99.69 and 99.68%, respectively. Maxillary second molars were more subjected to anatomical variations than first molars. Female patients presented higher prevalence of mesiolingual canals in the maxillary second molars. CONCLUSIONS: The most prevalent morphology in the maxillary first and second molars was three root canals. The presence of only one or two roots is more likely to occur in the maxillary second molars than in the maxillary first molars. Mesiolingual canals in mesiobuccal roots are more frequent in the maxillary first molars than in the maxillary second molars, and the occurrence of two distobuccal or two palatal canals is rare.

Separation of Nickel-Titanium Rotary and Reciprocating Instruments: A Mini-Review of Clinical Studies.

OBJECTIVE: This review aimed to evaluate clinical studies that assessed separated NiTi rotary and reciprocating instruments. DESIGN AND METHODS: This review assessed clinical studies involving treatments performed by undergraduate students, graduate students, and endodontic specialists. This review evaluated studies using rotary instruments, reciprocating instruments, and hybrid techniques. The number of uses of the different NiTi rotary and reciprocating systems was also assessed. RESULTS: The incidence of separation for rotary instruments ranged from 0% to 23%. Rotary instruments were used from 1 to 50 times depending on the instrument and tooth type. The lowest rate of incidence separation for rotary instruments was obtained by undergraduate students, using a hybrid technique. The separation incidence for reciprocating instruments ranged from 0% to 1.71%. Reciprocating instruments were mostly single-used; one study reported their use up to 3 times. Separation rate in reciprocating instruments was similar in single-use or in multiple uses 0.2%. CONCLUSIONS: Separation of instruments has dropped recently and seems to be a minor problem in current Endodontics. Multiple uses of NiTi rotary instruments are a possibility without significantly increasing the risk of instrument separation. Single and multiple uses of NiTi reciprocating instruments are also associated with low incidence of separation. Attempting to remove separated instruments should be carefully evaluated.

Locating the second mesiobuccal canal in maxillary molars: challenges and solutions.

The second mesiobuccal canal in mesiobuccal roots in maxillary molars is a common finding in root canal treatments. Failure on the location of these canals is associated with a high rate of unsuccessful treatments of maxillary molars. Its prevalence has been assessed in several in vitro and in vivo studies, presenting variations according to the methodology applied, along with the population of interest. While the anatomy of these teeth is well defined in micro-computed tomography studies, the clinical management is a great challenge for the practitioner. The use of a dental operating microscope has rendered a better clinical outcome when considering the location and treatment of this canal. On the other hand, cone-beam computed tomography use is still controversial in the efficacy of MB2 canal location. The association of a dental operating microscope with troughing performed with ultrasonic tips is an essential step in this location. Moreover, sodium fluorescein might be applied for root canal location. Due to the high rate of unsuccessful cases when the MB2 canal is not initially found, several cases are performed aiming to address the cases of missed MB2 canals. Therefore, the clinician should discuss the best possible approach, whether surgical or clinical. This article presents an overview of the importance of the MB2 canal on the outcomes of root canal treatments of maxillary molars. Solutions based in current literature will be presented accordingly.

Foraminal Deformation after Foraminal Enlargement with Rotary and Reciprocating Kinematics: A Scanning Electronic Microscopy Study.

INTRODUCTION: The aim of this study was to evaluate, under scanning electronic microscopy, the morphological aspect of apical foramen after root canal instrumentation with rotary and reciprocating kinematics at 2 different working length determinations. METHODOLOGY: Sixty mesiobuccal roots of mandibular and maxillary molars presenting with curvature ranging from 30 to 65° were used in this study. The roots were initially scanned with a scanning electronic microscope under ×50 magnification. Roots were divided into 2 different groups (n = 30): group 1 instrumented with rotary kinematics, and group 2 instrumented with reciprocating kinematics. Both groups were instrumented at 2 different working lengths: at the apex and 1 mm beyond the apex. The roots were scanned after the instrumentation at the apex and again after further instrumentation 1 mm beyond the apex. The photomicrographs obtained were assigned to 3 independent evaluators for foraminal deformation assessment through comparison with baseline images. Evaluators were masked with regard to the kinematics and working length used. The Pearson correlation test and Kruskal-Wallis test (method of Dunn) were used for statistical analysis (P < .05). RESULTS: The Pearson Correlation test showed good agreement among evaluators. Foraminal deformation was observed in instrumentation at the apex and 1 mm beyond the apex with both kinematics (P < .05). CONCLUSIONS: Within the limitations of this study, it can be concluded that root canal instrumentation at the apex or 1 mm beyond the apex promoted deformation of the major foramen, regardless of the kinematics.

Ex-vivo Smear Layer Removal Efficacy of Two Activated Irrigation Techniques After Reciprocating Instrumentation in Curved Canals.

INTRODUCTION: This study aimed to compare the effectiveness of two activated irrigation techniques in removing the smear layer after single-file reciprocating instrumentation in curved canals. MATERIALS AND METHODS: Sixty distobuccal roots of maxillary molars were standardized to create a closed system, and then instrumented using WaveOne Primary (Dentsply Maillefer, Ballaigues, Switzerland) instruments. Fifty-four specimens were randomly distributed into 3 groups for final irrigation: Non-activated irrigation, passive ultrasonic irrigation (PUI), and EndoActivator (EA;Dentsply Maillefer, Tulsa, USA) irrigation. All specimens received 3 mL of 17% EDTA for 1 minute, followed by irrigation with 6 mL of 2.5% NaOCl. The apical, middle and cervical thirds of the specimens were analyzed using scanning electronic microscopy (SEM), and the amount of remaining smear layer on the canal walls was rated by three examiners using a five-category scoring system. Kendall's concordance coefficient was used to assess inter-rater agreement. Kruskal-Wallis and Mann-Whitney (Bonferroni) tests were used to compare the scores. RESULTS: Kendall's concordance coefficient was ≥ 0.7, indicating an excellent level of agreement between the raters. No statistically significant difference in irrigation techniques efficacy for removal of the smear layer (p=0.061) was found for the apical third. The scores attributed to the specimens irrigated with the EA system were significantly lower than those of the other groups in the cervical and middle thirds (p< 0.05). CONCLUSIONS: The efficacy of the EA system in removing the smear layer in the cervical and middle thirds of root canals instrumented with reciprocating motion was significantly higher than that of either PUI or non-activated irrigation. Both EA and PUI performed similarly in apical third.

In vivo assessment of accuracy of Propex II, Root ZX II, and radiographic measurements for location of the major foramen.

OBJECTIVES: The aim of this in vivo study was to assess the accuracy of 2 third-generation electronic apex locators (EALs), Propex II (Dentsply Maillefer) and Root ZX II (J. Morita), and radiographic technique for locating the major foramen (MF). MATERIALS AND METHODS: Thirty-two premolars with single canals that required extraction were included. Following anesthesia, access, and initial canal preparation with size 10 and 15 K-flex files and SX and S1 rotary ProTaper files, the canals were irrigated with 2.5% sodium hypochlorite. The length of the root canal was verified 3 times for each tooth using the 2 apex locators and once using the radiographic technique. Teeth were extracted and the actual WL was determined using size 15 K-files under a × 25 magnification. The Biostat 4.0 program (AnalystSoft Inc.) was used for comparing the direct measurements with those obtained using radiographic technique and the apex locators. Pearson's correlation analysis and analysis of variance (ANOVA) were used for statistical analyses. RESULTS: The measurements obtained using the visual method exhibited the strongest correlation with Root ZX II (r = 0.94), followed by Propex II (r = 0.90) and Ingle's technique (r = 0.81; p < 0.001). Descriptive statistics using ANOVA (Tukey's post hoc test) revealed significant differences between the radiographic measurements and both EALs measurements (p < 0.05). CONCLUSIONS: Both EALs presented similar accuracy that was higher than that of the radiographic measurements obtained with Ingle's technique. Our results suggest that the use of these EALs for MF location is more accurate than the use of radiographic measurements.

Light-emitting diode assessment of dentinal defects: the role of presumed extraction forces.

OBJECTIVES: The evaluation of iatrogenic dentinal defects in extracted teeth may be influenced by extraction forces and prolonged dry times. The purpose of this study was to compare the presence of dentinal defects in freshly extracted, periodontally compromised teeth with those in a group of teeth with uncontrolled extraction forces and storage time. MATERIALS AND METHODS: The experimental group consisted of eighteen roots obtained from teeth extracted due to periodontal reasons with class II or III mobility. They were kept in saline and sectioned within 1 hour following extraction. The control group consisted of matched root types obtained from an anonymous tooth collection, consistent with previous dentinal defect studies. The slices were obtained at 3, 6, and 9 mm from the apex. The imaging process exposed all specimens to no more than 60 seconds of dry time. The × 12.8 magnification was used for the 9 mm slices and × 19.2 magnification for the 3 mm and 6 mm slices under light-emitting diode (LED) transillumination. The root canal spaces and periodontal tissues were masked to minimize extraneous factors that might influence the evaluators. Chi-square test was used for statistical analysis. RESULTS: Dentinal defects were detected in 17% of the experimental group teeth, compared to 61% of control teeth (p = 0.015). CONCLUSIONS: LED transillumination assessment of freshly extracted roots with class II or III mobility showed smaller number of dentinal defects than roots with uncontrolled storage time and extraction forces. The use of freshly extracted roots with mobility should be considered for future dental defect assessment studies.

Safety Assessment of Two Hybrid Instrumentation Techniques in a Dental Student Endodontic Clinic: A Retrospective Study.

The aim of this study was to retrospectively assess the safety potential of a hybrid technique combining nickel-titanium (NiTi) reciprocating and rotary instruments by third- and fourth-year dental students in the predoctoral endodontics clinic at one U.S. dental school. For the study, 3,194 root canal treatments performed by 317 dental students from 2012 through 2015 were evaluated for incidence of ledge creation and instrument separation. The hybrid reciprocating and rotary technique (RRT) consisted of a glide path creation with stainless steel hand files up to size 15/02, a crown down preparation with a NiTi reciprocating instrument, and an apical preparation with NiTi rotary instruments. The control was a traditional rotary and hand technique (RHT) that consisted of the same glide path procedure followed by a crown down preparation with NiTi rotary instruments and an apical preparation with NiTi hand instruments. The results showed that the RHT technique presented a rate of ledge creation of 1.4% per root and the RRT technique was 0.5% per root (p<0.05). Three stainless steel hand files separated: two in the RHT group and one in the RRT group. There was no separation of any NiTi file in any of the techniques. The use of the reciprocating and rotary technique for root canal instrumentation by these dental students provided good safety. This hybrid technique offered a low rate of ledge creation along with no NiTi instrument separation.