Faculty Bibliography

This study compared the torque generation during canal shaping with a nickel-titanium endodontic instrument according to the extent of glide-path establishment. Seventy-five simulated S-shaped canal blocks were divided into five groups (n = 15) according to the number of repetitive insertions to the working length using a One G glide-path instrument: groups with 5, 10, 15, and 20 insertions as well as group Z without glide-path establishment. When the tip of the One G file reached the working length, the file was moved back and forth repetitively at the working length for the designated number of times for each group. The instrumentation procedure with HyFlex EDM had 15 pecking strokes. During instrumentation, the generated torque was transmitted to a customized data acquisition module and collected using customized software. Data were computed to determine the maximum torque and total stress. The maximum screw-in forces were statistically analyzed using one-way analysis of variance and Tukey's post hoc comparison test with a significance level of 95%. While the maximum stress did not have significant differences among the five groups (p > 0.05), groups with more than 10 repetitive insertions generated lower total stress during instrumentation than did the group with 5 insertions and group Z (p < 0.05). Under the limitations of this study, repetitive insertions of glide-path establishment files at the working length reduced stress generation during the shaping using nickel-titanium instruments.

The European Society of Endodontology and the American Association for Endodontists have released position statements and clinical considerations for regenerative endodontics. There is increasing literature on this field since the initial reports of Iwaya et al. (2001) and Banchs & Trope (2004). Endogenous stem cells from an induced periapical bleeding and scaffolds using blood clot, platelet rich plasma or platelet rich fibrin have been utilized in regenerative endodontics. This approach has been described as a 'paradigm shift' and considered the first treatment option for immature teeth with pulp necrosis. There are three treatment outcomes of regenerative endodontics; 1) Resolution of clinical signs and symptoms; 2) further root maturation; and 3) return of neurogenesis. It is known that results are variable for these objectives and true regeneration of the pulp/dentine complex is not achieved. Repair derived primarily from the periodontal and osseous tissues has been shown histologically. It is hoped that with the concept of tissue engineering; namely stem cells, scaffolds and signaling molecules that true pulp regeneration is an achievable goal. This review discusses current knowledge as well as future directions for regenerative endodontics. Patient-centered outcomes such as tooth discoloration and possibly more appointments with the potential for adverse effects needs to be discussed with patients and parents. Based on the classification of Cvek (1992), it is proposed that regenerative endodontics should be considered for teeth with incomplete root formation though teeth with near or complete root formation may be more suited for conventional endodontic therapy or MTA barrier techniques. However, much is still not known about clinical and biological aspects of regenerative endodontics.

Avulsion of permanent teeth is one of the most serious dental injuries, and a prompt and correct emergency management is very important for the prognosis. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the task group. The guidelines represent the current best evidence and practice based on literature research and professionals' opinion. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion or majority decision of the task group. Finally, the IADT board members were giving their opinion and approval. The primary goal of these guidelines is to delineate an approach for the immediate orurgent care of avulsed permanent teeth.

Traumatic dental injuries (TDIs) of permanent teeth occur frequently in children and young adults. Crown fractures and luxations are the most commonly occurring of all dental injuries. Proper diagnosis, treatment planning and followup are important for improving a favorable outcome. Guidelines should assist dentists and patients in decision making and for providing the best care effectively and efficiently. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the best current evidence based on literature search and professional opinion. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of TDIs. In this first article, the IADT Guidelines for management of fractures and luxations of permanent teeth will be presented.

This study compares the safety limits and torsional resistances of WaveOne Gold (WOG) and WaveOne (WO) endodontic files while using the original motor. The safety limits for reciprocating angles were tested by measuring the torsional limit before plastic deformation (TLP) after repetitive torsional loading at gradually increasing load, and after single continuous rotation. Statistical analysis was performed by independent t-test at 95% confidence level. The tested specimens were observed under a scanning electron microscope (SEM). Regardless of the test mode, the distortion angle at the TLP was higher for WOG than WO (p < 0.05), and all were greater than the 150-degree rotation of the original motor. The mean values of the distortion angle and torque from the single continuous rotation loading were significantly lower than those with repetitive loading movements. Comparing the two systems under SEM, WO showed a catastrophic change in comparison with WOG. Evaluation of the lateral aspects showed longitudinal micro-cracks after 270-degree repetitive movements. After 150-degree repetitive movements, no distorted machining grooves were found in either group, but WO showed evidence of longitudinal micro-cracks. Under the conditions of this study, the torsional loading from the pre-set mode of the dedicated motor for WO was safe for WOG as well.

BACKGROUND/AIM/OBJECTIVE:Dental trauma in school populations has a high frequency and school teachers are often close to the place where such injuries occur. However, many studies have confirmed the lack of knowledge as to how to act in these cases. The aim of this study was to determine the knowledge in regard to dental trauma of school teachers in Colombia. MATERIALS AND METHODS/METHODS:A multi-centre, descriptive cross-sectional study was performed in 251 schools using a stratified randomized sampling. A structured hard copy survey was personally delivered to 2,390 school teachers in the selected schools. The survey contained questions related to work experience, teaching level and demographic data, as well as questions related to their knowledge of and attitude towards emergency dental trauma management. RESULTS:The response rate was 96%. Most of the school teachers (95%) had never received training related to dental trauma although, 35% had witnessed at least one case. Out of 2,296 school teachers surveyed, only 5.8% would have replanted an avulsed tooth. An association was found between work experience and appropriate management of an avulsed tooth. No significant differences were found in regard to school location (city), school type (private/public), gender and school teachers' education level. CONCLUSIONS:The knowledge of school teachers in Colombia about emergency dental trauma management is inadequate. The findings strongly suggest a need for an education strategy with the involvement of the government, dentistry schools and private organizations.

INTRODUCTION/BACKGROUND:This report includes outcomes for a group of patients with significant periapical lesions who were treated and evaluated in two single-arm, multicenter, prospective, nonsignificant risk clinical studies. METHODS:Forty-five teeth were from 45 patients who met the inclusion criteria and consented for the clinical studies and were diagnosed with periapical lesions with periapical index score ≥3. Patients were treated with a standardized treatment protocol including instrumentation to an apical diameter of #20 without orifice enlargement, the GentleWave Procedure, and warm vertical obturation. Clinical signs and radiographic assessments were evaluated at 12 months to assess healing. Success was classified as healing or healed and accounted for the cumulative success rate of healing. Statistical analyses were performed by using Fisher exact test, Pearson correlation, and multivariate logistic regression analyses. RESULTS:At 12 months, 44 of 45 teeth (97.8%) were evaluated. The cumulative success rate for the GentleWave Procedure was 97.7%. Forty-three of 44 teeth were completely functional; all teeth had complete resolution for measured indices of mobility, soft tissue lesions, sinus tract, and furcation involvement. No patients experienced moderate or severe pain at 2, 7, and 14 days after procedure. Although only 1 patient was unsuccessful and the presence of clinical symptoms and type of periradicular diagnosis at 12 months were correlated with an unsuccessful outcome, the analyses were limited by the sample size. CONCLUSIONS:In this case series analysis, treatment of sizable periapical lesions with the GentleWave Procedure resulted in a success rate of 97.7% at 12-month re-evaluation.

Periodontists are often called upon to provide treatment for furcation bone loss. However, periodontal disease is only one cause of bone loss within the furcation of teeth. Endodontic pathosis, tooth fractures, periodontal disease, as well as non-odontogenic causes, must be considered before beginning treatment. Periodontal treatment of a furcation defect should never be done without a proper endodontic diagnosis. Radiographic and clinical findings can help the clinician arrive at a correct diagnosis. While some furcation defects are relatively simple to treat and have a good long-term prognosis, others can render a tooth hopeless. A new etiology-based classification system of furcation defects is needed to lead the clinician to a proper diagnosis. Understanding the etiology of the defect is critical to avoiding unnecessary, irreversible and ineffective procedures. [ABSTRACT FROM AUTHOR]

INTRODUCTION: The aim of this study was to evaluate the effect of different pecking depth on the stress generated by the screw-in forces of a rotating endodontic file in simulated canals. METHODS: Twenty simulated resin blocks with a J-shaped curvature were used. Twenty OneG files (MicroMega, Besancon, France) were assigned for a screw-in test depending on the pecking depth in 2 groups (n = 10). The files were operated at 300 rpm, and the up and down speed was controlled at 1 mm/s stroke velocity and a 10-millisecond dwell time using a customized device. The distances (pecking depth) for the pecking motion were 2 mm or 4 mm for each group; "6 mm forward and 4 mm backward" and "6 mm forward and 2 mm backward" movements were applied, respectively, for the 2 pecking groups. During the operation, the positive and negative apical loads were recorded at a rate of 50 Hz using customized software attached to the device. The maximum negative apical load (screw-in force [SF]) was recorded, and the total energy during pecking motion until the file reached the working length (cumulative screw-in forces [CSFs]) was computed. The data were analyzed using an independent t test at a significance level of 95%. RESULTS: No significant difference in SF was found between the 2 groups of pecking depths. However, the longer pecking depth (4-mm group) showed a significantly larger CSF compared with the shorter pecking depth group (P < .05). CONCLUSIONS: The shorter pecking depth may generate lower overall stresses for the root dentin as well as the instrument.

Traumatic dental injuries (TDIs) of permanent teeth occur frequently in children and young adults. Crown fractures and luxations are the most commonly occurring of all dental injuries. Proper diagnosis, treatment planning and followup are important for improving a favorable outcome. Guidelines should assist dentists and patients in decision making and for providing the best care effectively and efficiently. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the best current evidence based on literature search and professional opinion. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of TDIs. In this first article, the IADT Guidelines for management of fractures and luxations of permanent teeth will be presented.