Arias A, de la Macorra JC, Hidalgo JJ, Azabal M.Predictive models of pain following root canal treatment: a prospective clinical study. International Endodontic Journal, 46, 784-793, 2013. Aim To determine the probability of the incidence, intensity, duration and triggering of post-endodontic pain, considering factors related to the patient (age, gender, medical evaluation) and to the affected tooth (group, location, number of canals, pulp vitality, preoperative pain, periapical radiolucencies, previous emergency access, presence of occlusal contacts with antagonist). Methodology A total of 500 one-visit root canal treatments (RCTs) were performed on patients referred to an endodontist. Shaping of root canals was performed manually with Gates-Glidden drills and K-Flexofiles, and apical patency was maintained with a size 10 file. A 5% NaOCl solution was used for irrigation, and canals were filled with lateral compaction and AH-Plus sealer. Independent factors were recorded during the treatment, and characteristics of post-endodontic pain (incidence, intensity, type and duration) were later surveyed through questionnaires. Of the 500 questionnaires, 374 were properly returned and split in two groups for two different statistical purposes: 316 cases were used to adjust the logistic regression models to predict each characteristic of post-endodontic pain using predictive factors, and the remaining 58 cases were used to test the validity of each model. Results The predictive models showed that the incidence of post-endodontic pain was significantly lower when the treated tooth was not a molar (P = 0.003), demonstrated periapical radiolucencies (P = 0.003), had no history of previous pain (P = 0.006) or emergency endodontic treatment (P = 0.045) and had no occlusal contact (P < 0.0001). The probability of experiencing moderate or severe pain was higher with increasing age (P = 0.09) and in mandibular teeth (P = 0.045). The probability of pain lasting more than 2 days was increased with age (P = 0.1) and decreased in males (P = 0.007) and when a radiolucent lesion was present on radiographs (P = 0.1). Conclusions Predictive formulae for the incidence, the intensity and the duration of post-endodontic pain were generated and validated taking account of the interrelation of multiple concomitant clinical factors. A predictive model for triggering post-endodontic pain could not be established.

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INTRODUCTION A novel S-shaped rotary file was developed to conform to nonround canal cross sections. However, the instrument should also perform well in small curved canals. This study used micro-computed tomographic scans to test the effects of TRUShape (Dentsply Tulsa Dental Specialties, Tulsa, OK) and a conventional rotary on canal geometry. METHODS Twenty mandibular molars with independent mesial canals were submitted to preoperative micro-computed tomographic scans (20-m resolution). Canals were randomly allocated to 2 groups using Vortex (Dentsply Tulsa Dental Specialties) and TRUShape for shaping according to the directions for use. Scans were obtained after size 20/.06 and 30/.06; the following outcome variables were calculated: dentin volume, smallest radicular wall thickness, treated canal surface, canal transportation, and accumulated hard tissue debris. The number of preparation errors was tabulated; data were statistically contrasted using repeated measures and factorial analyses of variance. RESULTS The initial canal sizes were similar in both groups. Both instruments promoted preparation with no overt procedural errors. Vortex removed significantly more dentin both at size 20 and 30 (P < .02). Significantly (P < .02) more radicular wall dentin remained toward the furcation in the TRUShape group (1.02 ± 0.25 mm vs 0.94 ± 0.22 mm). The untreated surface at size 20 was 28.5 ± 13.9 and 19.4 ± 8.9 (P < .05), and it was 15.1 ± 8.5 and 11.3 ± 4.9 (P > .05) at size 30 for TRUShape and Vortex, respectively. Canal transportation at size 30 varied between 85 ± 57 m and 179 ± 65 m; the overall transportation scores were significantly lower for TRUShape (P < .05). CONCLUSIONS TRUShape provided conservation of dentin by limiting dentin removal and in the absence of substantial canal transportation. In the present study, the use of TRUShape in the mesial canals of mandibular molars did not result in decreased amounts of unprepared canal surface. Abstract: Introduction: A novel S--shaped rotary file was developed to conform to non--round canal cross--sections. However, the instrument should also perform well in small curved canals. This study used microCT scans to test the effects of TRUShape and a conventional rotary on canal geometry. Methods: Twenty mandibular molars with independent mesial canals were submitted to preoperative microCT scans (20µm resolution). Canals were randomly allocated to two groups, using Vortex and TRUShape (both Dentsply Tulsa Dental) for shaping according to the directions for use. Scans were obtained after size 20/.06 and 30/.06; outcome variables were removed dentin volume, smallest radicular wall thickness, treated canal surface and canals transportation as well as accumulated hard tissue debris. Numbers of preparation errors were tabulated; data was statistically contrasted using repeated measures and factorial ANOVAs. Results: Initial canal sizes were similar in both groups. Both instruments promoted preparation with no overt procedural errors. Vortex removed significan...

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