Faculty Bibliography

This study aimed to compare the fatigue resistance of files made from different heat treatment methods and surface treatment. Four prototype files were created through heat treatment and titanium coating surface treatment (AT, DT, ER, EN; named arbitrarily by the manufacturer) at different times and temperatures. Artificial canals with curvatures of 45- and 90-degree were used for the fatigue testing. The files were operated at the speed of 500 rpm at 37 °C, and the time until fracture incurred by a 4-mm dynamic pecking motion at a speed of 8 mm/s was measured, and the number of cycles to failure (NCF) was calculated by applying rotation speed and time. The length of the fractured fragment was measured. The fractured specimens were observed under the SEM to compare the characteristics of fatigue fracture patterns. Differential scanning calorimetry analysis was performed to estimate the phase transformation temperature. One-way ANOVA with Duncan"™s post-hoc comparison, the Kruskal"“Wallis test, and Mann"“Whitney U were applied to compare the fatigue resistance among the prototypes at a significance level of 95%. Regardless of the canal angle, the EN showed the highest fatigue resistance (p < 0.05). AT had the lowest NCF at the 90-degree canal (p < 0.05). ER had a higher NCF than the DT at 45 degrees (p < 0.05), but there was no difference at 90 degrees. DSC analysis revealed that the ER and EN groups exhibited two austenite peaks above 40 °C. In conclusion, the file that underwent a specific temperature heat treatment with titanium coating surface treatment showed the highest fatigue resistance.

INTRODUCTION/BACKGROUND:This epidemiological analysis used procedure codes from dental insurance claims data to identify apexification cases and evaluate survival at the tooth-level. METHODS:Dental insurance claims data from New York State (2006-2019) and Massachusetts (2013-2018) were used in an observational, retrospective cohort study to evaluate the provision and treatment outcomes of apexification. Statistical analyses included Kaplan-Meier survival estimates and Cox proportional hazards regression. Cox proportional hazard regression was used to evaluate the hazard of adverse event occurrence by age, gender, tooth type, placement of permanent restoration, and dental provider type. A sensitivity analysis evaluated potential bias in the survival estimates and adjusted hazard ratios (aHRs) due to differential loss to follow-up. Robust standard errors were used to account for potential dependence between teeth within an individual. RESULTS:The analytic cohort of 575 individuals included 632 teeth, with an average follow-up time of 64 months. The survival rates of apexification procedures were 95% at 1 year; 93% at 2 years; 90% at 3 years; and 86% at 5 years. Tooth retention following apexification was 98% at 1 year; 96% at 2 years; 95% at 3 years; and 90% at 5 years. Tooth type and subsequent placement of a permanent restoration were significant predictors of survival after apexification. CONCLUSIONS:The procedural and tooth survival outcomes of apexification were high and comparable to studies that analyzed clinical data on tooth survival following apexification.

INTRODUCTION/BACKGROUND:This study evaluated the effect of periodic changes in rotation speed on torsional stress and screw-in force using the dedicated alternative rotation technique (ART) motion of the EQ-M (Metabiomed, Cheongju, Korea) endodontic motor. METHODS:Two ART modes of the EQ-M motor in 2 alternative techniques (ART30 and ART50) and continuous rotation were compared using ProTaper Next X2 (Dentsply Sirona, Charlotte, NC) files and simulated resin blocks (n = 12 per group). ART30 and ART50 were operated by continuous rotation of 350 rpm for 360° and then rotated at 30% increased speed from the base speed for 180° and at 50% increased speed for 180°, respectively. Before the test, the simulated resin blocks were pre-enlarged using ProTaper Gold S1 and S2 (Dentsply Sirona) and fixed on a metal stage connected to the force- and torque-measuring unit. During shaping the simulated canal in an automatic up-and-down manner, the parameters of maximum torque, sum of torque, maximum screw-in force, and maximum apical force were measured. The data were statistically analyzed using 1-way analysis of variance and the Tukey post hoc comparison test at the 95% significance level. RESULTS:The ART30 and ART50 groups showed a lower maximum torque, sum of torques, screw-in force, and apical drive force than the continuous rotation group. There was no significant difference between the ART30 and ART50 groups (P > .05). When the screw-in force increased suddenly, the torque correspondently increased. CONCLUSIONS:Under the limitations of this study, the ART mode could reduce the torsional stress and apical forces of the screw-in during instrumentation in comparison with continuous rotation.

BACKGROUND:Previously published epidemiological outcome studies of root canal therapy (NSRCT) in the Unites States utilize data only from a single, private dental insurer for adult populations. AIM/OBJECTIVE:This study aimed to investigate outcomes of initial NSRCT, performed on permanent teeth, in a publicly insured pediatric population. DESIGN/METHODS:New York State Medicaid administrative claims were used to follow 77,741 endodontic procedures in 51,545 patients aged 6-18, from the time of initial NSRCT until occurrence of an untoward event (retreatment, apicoectomy, extraction). Initial treatment and untoward events were identified by Current Dental Terminology codes. Kaplan-Meier survival estimates were calculated at 1, 3, and 5 years. Hazard ratios for time to permanent restoration and restoration type were calculated using Cox proportional hazard models. RESULTS:Median follow-up time was 44 months [range:12-158 months]. Procedural, NSRCT, survival was 98% at 1 year, 93% at 3 years, and 88% at 5 years. Extraction was the most common untoward event. Teeth permanently restored with cuspal coverage had the most favorable treatment outcomes. CONCLUSIONS:Overall, 89% of teeth were retained and remained functional over a minimum follow-up time of 5 years. These results elucidate expected outcomes of NSRCT in permanent teeth for pediatric patients with public-payer dental benefits.

BACKGROUND:A comprehensive effort to evaluate outcomes of primary root canal treatment (RCT) between 1966 and 2002 was published by Ng et al. (2007, 2008). Changes in endodontic materials and treatment methods warrants an updated analysis of outcomes. OBJECTIVES/OBJECTIVE:This study aimed to 1) quantify the success rates of primary RCT published between 2003 and 2020; and 2) investigate the influence of some characteristics known/ suspected to be associated with treatment outcomes. METHODS:An electronic search was performed in the following databases (01-01-2003 to 12-31-2020): Pubmed, Embase, CINHAL, Cochrane and Web of Science. Included study designs were longitudinal clinical studies (randomized control trials, cohort studies, retrospective observational studies). Studies with at least twelve-months of post-operative review and success rates based on clinical and radiographic criteria were analyzed. The terms 'strict' (complete resolution of periapical lesion) or 'loose' (reduction in size of existing periapical lesion) were used to describe the outcome criteria. Weighted, pooled success rates were calculated. Random effects meta-regression models were used to investigate potential sources of statistical heterogeneity. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to evaluate for quality assessment of the included studies. RESULTS:Forty-two studies were included in the review. Meta-analyses showed that the weighted pooled success rates were estimated to be 92.6% (95% CI: 90.5-94.8%) under 'loose criteria' and 82.0% (95% CI: 79.3-84.8%) under 'strict' criteria. The most significant areas of study heterogeneity were year of publication and qualification of operator. The majority (64.29%) of studies were considered to be of low quality of evidence. DISCUSSION/CONCLUSIONS:Biological factors continue to have the most significant impact on RCT outcomes. The technological method of instrumentation had no significant effect. The quality of evidence, was based primarily on study design and only randomized control trials were considered to be "high" quality of evidence. CONCLUSIONS:The reported success rates show improvement over time. Weighted success rates for studies with a minimum of four-year follow-up had better outcomes, compared to those with less than four years, when 'strict criteria' were used.

Introduction and Objectives/UNASSIGNED:Local anesthesia is essential in dentistry in providing intraoperative analgesia and anesthesia. However, knowledge related to its use for management of post-operative pain is limited. Perioperative pain management is especially important for root canal treatment (ie, endodontic therapy), performed by endodontists. In this study, we sought to better understand endodontists' attitudes regarding the use of long-lasting anesthetic, namely 0.5% bupivacaine HCl with 1:200,000 epinephrine, for the management of post-endodontic pain. Additionally, we aimed to understand the perspectives of dental patients about receiving longer lasting anesthesia for endodontic therapy and to determine factors that affect their anesthetic preferences within the orofacial region. Methods/UNASSIGNED:An email invitation to participate in an anonymous online survey was sent to members of the American Association of Endodontists. Also, 82 patients attending an in-person visit to an endodontic clinic were recruited to the study. Results/UNASSIGNED:Data from 474 endodontic practitioners and 82 patients included in analysis. Among practitioners, the majority reported to either never (33.31%) or rarely (34.84%) using bupivacaine. Most chose "I don't think I need it" (47%) and "patient discomfort because of longer duration of soft tissue anesthesia" (30.81%) as reasons for not preferring the use of bupivacaine. Of the practitioners who reported at least rare use, most chose bupivacaine for post-operative pain management (78.02%). Conversely, 52% of patients reported that they were likely/most likely to request long-lasting anesthetics for post-operative pain control. Conclusion/UNASSIGNED:Bupivacaine is rarely used as a post-operative pain management strategy for endodontic therapy. Specifically, bupivacaine is not preferred not because of adverse events, toxicity, or slow onset concerns, but rather, because of longer duration of soft tissue anesthesia. However, our data suggest that patients may be willing to receive long-lasting anesthesia. Further patient-centered research should investigate the use of long-lasting anesthetic agents for management of post-endodontic pain.

There is no consensus on the true meaning of clinical regenerative endodontics, and there is confusion over the concept and the term. Commonly used terms include revitalization and revascularization. The clinical methods for endodontic revitalization procedures and the tissue engineering concept differ depending on whether there is exogenous delivery of cells - called cell therapy, or not. Here, in this review, the difference is clarified by emphasizing the correct terminology: cell-free versus cell-based regenerative endodontic therapy (CF-RET versus CB-RET). The revitalization procedures practised clinically do not fit into the modern tissue engineering concepts of pulp regeneration but can be categorized as CF-RET. The modern tissue engineering concept in pulp regeneration is a CB-RET, which so far is at the clinical trial stage. However, histological examination of teeth following regenerative endodontic treatments reveals healing with repair derived from stem cells that originate from the periodontal, bone and other tissues. The aim of regenerative endodontics is regeneration of the pulp-dentine complex. This review discusses why CF-RET is unlikely to regenerate a pulp-dentine complex with current protocols. The American Association of Endodontists and the European Society of Endodontology have not yet recommended autologous stem cell transplantation (CB-RERT) which aspires for regeneration. Therefore, an understanding of the concept, term, difficulties and differences in current protocols is important for the clinician. However, rather than being discouraged that ideal regeneration has not been achieved to date, repair can be an acceptable outcome in clinical regenerative endodontics as it has also been accepted in medicine. Repair should also be considered in the context that resolution of the clinical signs/symptoms of pulp necrosis/apical periodontitis is generally reliably obtained in clinical regenerative endodontics.

The American Association of Endodontists (AAE) Consensus Conference Recommended Diagnostic Terminology states that mature permanent teeth clinically diagnosed with irreversible pulpitis are treated with pulpectomy and root canal filling because inflamed vital pulp is not capable of healing. Histological studies have demonstrated that clinically diagnosed irreversible pulpitis does not involve the entire pulp. A recent International Endodontic Journal Editorial suggested clinical diagnosis of pulp disease should be reassessed because of the poor correlation between clinical symptoms and pulp sensibility testing and the actual histological status of the pulp. This review identified studies in a PubMed search that provide evidence for vital pulp therapy (VPT) of mature permanent teeth with irreversible pulpitis is predictable if correctly diagnosed and properly treated. A narrative review was undertaken to outline the correlation between the clinical symptoms/signs and pulp sensibility testing and the histological findings of the pulp. Treatment procedures for permanent teeth are outlined.

The current American Association of Endodontists clinical considerations for a regenerative endodontic procedure state that a regenerative procedure is suitable for immature permanent teeth with necrotic pulp when the pulp space is not needed for a post/core in the final restoration. Therefore, many immature permanent teeth with necrotic pulp that have sustained a substantial loss of coronal tooth structure either from caries or trauma are treated by apexification or mineral trioxide aggregate/Biodentine (Septodent, Lancaster, PA) apical barrier techniques in which no further root maturation would occur. This case series presents 10 immature permanent teeth with necrotic pulp in which a post/core was likely required in the future for adequate coronal restoration because of loss of substantial coronal tooth structure and a modified apexification procedure was used. All 10 cases after the modified apexification procedure showed no clinical symptoms/signs and showed radiographic evidence of healed/healing of periapical lesion after a 2-year review. Eight cases showed increased thickness of the apical root canal walls, increased apical root length, and apical closure. The overall percentage change in root length was 7.52%, in root width at the apical one third it was 18.89%, and in radiographic root area it was 15.04% at the 24- to 72-month follow-up period. This modified apexification procedure allows for the tooth to be restored with a post/core if required for the final restoration in the future as well as continued root development.