Effects of five levels of noise reduction applied to indirect digital radiography on diagnostic accuracy of external apical root resorption.

BACKGROUND: Radiologic diagnosis of external apical root resorption (EARR) is clinically important. Noise might disrupt this diagnosis. Therefore, we assessed the efficacy of noise reduction on periapical indirect digital radiography. MATERIALS AND METHODS: This in vitro study as performed on 792 radiographs. A total of 66 single-rooted premolars were inserted in dried hemimandibles of sheep and fixed with modeling wax. Digital images were obtained using the parallel technique. The storage phosphor plates were processed in the DIGORA Optime scanner. The resulting images were sent to a computer using the Scanora software for radiographic analysis. The teeth were removed from the mandible, and artificial EARR defects were simulated. Afterward, the indirect digital radiographs were obtained at the same condition of the baseline. Five levels of noise reduction were applied. All images were saved in Digital Imaging and Communications in Medicine format and monitored by two observers twice over 2 weeks. Data were analyzed statistically using Cochran and McNemar tests (α = 0.05). RESULTS: The highest sensitivity rate was found in the baseline group (0.99), and the lowest sensitivity was related to the "four-time noise reduction" method (0.91). The highest specificity rate was in the "five-times noise reduction" method (0.88) and the lowest specificity was associated with "one-time noise reduction" method (0.71). There was no statistical difference between images with/without noise reduction enhancement with varied gradation levels in terms of diagnostic accuracies of EARR (P > 0.05). CONCLUSION: Application of noise reduction procedure in Scanora software might have no effect on the accuracy of EARR diagnosis.

Postoperative endodontic pain of three different instrumentation techniques in asymptomatic necrotic mandibular molars with periapical lesion: a prospective, randomized, double-blind clinical trial.

OBJECTIVES: The purpose of this prospective, randomized, double-blind study was to compare postoperative pain of root canal treatment in patients with asymptomatic mandibular molar teeth with necrotic pulp and periapical lesion using three different instrumentation techniques: hand, multi-file rotary (ProTaper Universal), and reciprocating single-file (Wave-One) instrumentation techniques. MATERIALS AND METHODS: Ninety-six patients who fulfilled specific inclusion criteria were assigned to three groups according to the root canal instrumentation technique used: Hand (G1), ProTaper Universal (G2), and Wave-One (G3). One-visit root canal treatment was carried out, and the severity of the postoperative pain was assessed by the Heft-Parker visual analogue scale 6, 12, 18, 24, 48, and 72 h after treatment. Data were analyzed by Kruskal-Wallis, χ 2, Cochrane Q, one-way ANOVA, and Spearman's correlation analyses (α = 0.05). RESULTS: The patients in group 3 reported significantly lower postoperative pain levels at 6, 12, and 18 h compared with the patients in the two other groups (P < .05). In addition, the patients in group 2 reported significantly lower postoperative pain levels at 6 and 12 h compared with the patients in group 1 (P < .05). There were no significant differences in postoperative pain between the three groups at other time intervals (P > .05). The analgesic consumption was significantly higher in group 1 (P < .05), but no difference was seen between the two other groups (P > .05). CLINICAL RELEVANCE: Postoperative pain was significantly lower in patients undergoing root canal instrumentation with the Wave-One file compared with the ProTaper Universal and hand files.

Effect of Three Different Injection Sites on the Success of Anterior Middle Superior Alveolar Nerve Block with 3% Mepivacaine: A Randomized Controlled Trial.

AIM: Anterior middle superior alveolar (AMSA) nerve block injection targets the anterior superior alveolar nerve and the middle superior alveolar nerve branches of the infraorbital nerve through nutrient canals. Therefore, the central incisor to the second premolar teeth of one quadrant can be anesthetized. The aim of the present study was to evaluate the efficacy of AMSA nerve block injection with 3% mepivacaine solution at three different injection sites. MATERIALS AND METHODS: In a double-blind crossover study, 47 volunteers participated and three AMSA nerve block injections of 3% mepivacaine solution without epinephrine were administered at the anterior, posterior, and the most common injection sites with a 1-week interval between injections. Anesthesia of the central incisor to the second premolar of the injected side was evaluated by using an electric pulp tester. The success of the injection was considered as lack of response to two consecutive 80 readings. The generalized estimating equation analytic tests were administered (α = 0.05). RESULTS: The success rate of the AMSA nerve block injection ranged from 27.5-47.5% for the most common injection site and 22.5-42.5% for both the anterior and posterior injection sites. CONCLUSION: Changing the injection site did not result in statistically significant improvements (p > 0.05). CLINICAL SIGNIFICANCE: Changing the injection site anteropos-teriorly did not influence the success rate of the AMSA nerve block injection.

Effect of Contrast Inversion Enhancement on the Accuracy of Endodontic File Length Determination in Digital Radiography.

OBJECTIVE: The aim of this ex vivo study was to evaluate the accuracy of endodontic file length measurement on digital periapical radiographs after application of contrast inversion digital enhancement. MATERIALS AND METHODS: Forty single-rooted single-canal mature permanent human teeth with canals measuring 20-24 mm in length were used in this study. ISO #08 K-files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the gold standard. Standard periapical digital images were obtained with the Digora storage phosphor plates and Digora Optime scanner as the original images. The contrast inversion option of Scanora software program version 5.1 was used to produce enhanced images. Three radiologists and three endodontists measured file lengths on the original and enhanced images. The measurements were compared using repeated measures ANOVA and Bonferroni tests (α=0.05). RESULTS: There were significant differences between the measurement accuracy of the original and enhanced images (p<0.05). The enhanced images exhibited longer measurements compared to the original images. However, the two sets of digital radiographs provided significantly longer measurements compared to the gold standard (p<0.05). CONCLUSION: The contrast inversion tool of Scanora software program decreases measurement accuracy of the length of small endodontic files on digital periapical radiographs. It is suggested that contrast inversion should not be used in determining the lengths of small endodontic files.

Antibacterial effect of triantibiotic mixture versus calcium hydroxide in combination with active agents against Enterococcus faecalis biofilm.

The aim of the present study was to compare the antibacterial effect of calcium hydroxide (CH), triantibiotic mixture (TAM), and CH in combination with chlorhexidine (CHX), sodium hypochlorite (NaOCl) or colchicine (COL) against Enterococcus faecalis (E. faecalis) in surface and deep dentinal tubules. Seventy five fresh single-rooted human teeth were infected and divided into five experimental groups (n=15). The experimental groups were treated with CH+distilled water, CH+CHX, CH+NaOCl, CH+COL+distilled water and TAM+distilled water. Dentin chips obtained from surface and deep dentin of these root canals were prepared and analyzed by counting the number of colony forming units. There was significant difference between groups in the surface dentin (p<0.05). TAM showed higher antibacterial activity compared to CH-containing groups. There was no significant difference between TAM and CH-containing groups in the deep dentin (p>0.05). CH-containing medications and TAM can be used as effective disinfectants in treatment of infected root canals.

Effect of Patency File on Transportation and Curve Straightening in Canal Preparation with ProTaper System.

The aim of this ex vivo study was to evaluate the effect of using a patency file on apical transportation and curve straightening during canal instrumentation with the ProTaper rotary system. Seventy permanent mandibular first molars with mesiobuccal canals, measuring 18-23 mm in length and with a 25-40° curvature (according to the Schneider method), were selected. The working lengths were determined and the teeth were mounted and divided into two experimental groups: (A) prepared by the ProTaper system without using a patency file (n = 35) and (B) prepared by the ProTaper system using a patency file (n = 35). Radiographs taken before and after the preparation were imported into Photoshop software and the apical transportation, and curve straightening were measured. Data were analyzed using independent t-test. Partial correlation analysis was performed to evaluate the relationship between the initial curvature, transportation, and curve straightening (α = 0.05). Using a patency file during canal preparation significantly decreased both apical transportation and curve straightening (P < 0.001). There were significant relationships between the angle of curvature, transportation and curve straightening in pairs (P < 0.001). Apical patency is recommended during root canal preparation with the ProTaper rotary system.

Effect of digital noise reduction on the accuracy of endodontic file length determination.

PURPOSE: The aim of the present study was to evaluate the measurement accuracy of endodontic file length on periapical digital radiography after application of noise reduction digital enhancement. MATERIALS AND METHODS: Thirty-five human single-rooted permanent teeth with canals measuring 20-24 mm in length were selected. ISO #08 endodontic files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the standard value. Standard periapical digital images were obtained using the Digora digital radiographic system and a dental X-ray unit. In order to produce the enhanced images, the noise reduction option was applied. Two blinded radiologists measured the file lengths on the original and enhanced images. The measurements were compared by repeated measures ANOVA and the Bonferroni test (α=0.05). RESULTS: Both the original and enhanced digital images provided significantly longer measurements compared with the standard value (P<0.05). There were no significant differences between the measurement accuracy of the original and enhanced images (P>0.05). CONCLUSION: Noise reduction digital enhancement did not influence the measurement accuracy of the length of the thin endodontic files on the digital periapical radiographs despite the fact that noise reduction could result in the elimination of fine details of the images.

The accuracy of single emulsion radiographic film in linear measurement of spiral tomography.

BACKGROUND: Conventional tomography used for evaluation of the small areas of the jaws provides acceptable information. It has some advantages of availability, less radiation dose and cost in comparison to computed tomography (CT) and cone beam CT. Double emulsion film usually used for taking tomograms requires less exposure than single emulsion film; on the other hand, the latter provides more sharpness and spatial resolution. The aim of this study was to compare diagnostic accuracy of these two kinds of films in the spiral tomography. MATERIALS AND METHODS: In an experimental study, 20 lines (10 lines anterior and 10 lines posterior to the mental foramen) were selected on two dry human mandibles and tomographic images were taken from each line with and without metal marker by single and double emulsion films. For quantitative assessment, the mandibular width and length was identified and measured on 80obtained tomograms. Afterwards, the mandibles were sectioned on each line and their actual width and height were measured. For each line, the data of tomograms were subtracted from gold standard as measurement error. These errors were divided into three groups: Greater than +1 mm, between +1 mm and -1 mm and less than -1 mm. Obtained data were analyzed by Pearson Chi-square test (α=0/05). RESULTS: There was no significant difference between the single and double emulsion films, with and without markers in the measurement of both height and width of mandible (P > 0.05). CONCLUSION: The single emulsion film is not recommended to be used for taking the spiral tomogram.