Efficacy of a thermally treated single file compared with rotary systems in endodontic retreatment of curved canals: a micro-CT study.

OBJECTIVES: This study aimed to compare WaveOne Gold with ProTaper and RaCe systems regarding remaining filling material, apical transportation (AT), and working time (WT) after (i) filling removal and (ii) shaping of curved canals. METHODS: Thirty mesiobuccal canals of maxillary molars were prepared and filled. After 30 days, they were randomly assigned into three groups (n = 10), according to the instruments used for filling removal and shaping, respectively: WOG-WaveOne Gold Primary and Medium; PTG-ProTaper Retreatment and ProTaper Next; RCG-D-RaCe and RaCe. Micro-CT analysis assessed the residual filling material and AT. WT was recorded. Data were statistically analyzed (α = .05). RESULTS: There was no significant difference between groups in the amount of filling material at any evaluated moment (P > .05). All groups presented low AT values. The WT was similar in all groups in filling removal (P > .05), and in shaping step WOG was faster than PTG and RCG (P < .05). CONCLUSIONS: Neither system could completely remove the filling material. The instruments evaluated were safe and the reciprocating system was faster than the rotary systems in shaping the canals. CLINICAL RELEVANCE: This study provided consistent information on filling material removal capacity of WaveOne Gold. Considering that all tested systems were safe, WaveOne Gold may be an alternative with cost-effectiveness and shorter learning curve for endodontic retreatment.

Root canal preparation in 3-rooted maxillary premolars through hand, rotary, and reciprocating techniques: a microcomputed tomography evaluation.

Endodontic management of 3-rooted maxillary premolars is a challenge due to their complex anatomy and narrow root canal walls. This study aimed to evaluate, by microcomputed tomography (µCT), the apical enlargement and centering ability promoted by hand, rotary, and reciprocating instrumentation in 3-rooted maxillary premolars. Eighteen teeth were divided into 3 groups (n = 6) according to the preparation technique: crown-down hand, rotary, and reciprocating instrumentation. Instruments with similar apical diameters were used (25 and 40 mm for buccal and palatal canals, respectively). Centering ability and canal enlargement were evaluated through the comparison of µCT images obtained before and after instrumentation. Distances of 0, 2, 4, and 6 mm from the apical stop were considered. Differences between canal areas before and after instrumentation were calculated. In addition, distances between the original canal center and the prepared canal center at the apical stop were measured in both the mesiodistal and buccopalatal directions. Significant differences in enlargement areas and centering ability among the techniques were determined using 2-way analysis of variance and Tukey post hoc test (P > 0.05). Root canal enlargement was similar for all techniques. Excessive enlargement was observed in only a few specimens, and root perforation did not occur. Some specimens presented untreated canal areas. In mesiobuccal and distobuccal roots, reciprocating instrumentation promoted more centered preparations than hand instrumentation when measured in the mesiodistal direction (P > 0.05). There were no other statistically significant differences. The results established that hand, rotary, and reciprocating techniques presented similar safety margins for instrumentation of the apical third of 3-rooted maxillary premolars. Reciprocating instrumentation presented some advantages over hand preparation regarding centering ability.

Radiolucent halos beneath composite restorations do not justify restoration replacement.

PURPOSE: To determine the correlation between the presence of radiolucent areas (RA) beneath composite restorations and gaps and remaining demineralized tissue (RDT). METHODS: 50 extracted teeth (sound and carious) were studied. After caries removal, cavities were filled. Artificial cavities were created and filled in the sound teeth. Samples were sectioned and analyzed with stereomicroscopy. RESULTS: Gap/RDT was observed in 38.9% [95% confidence interval (CI) =28.2-50.5] and 68.9% (95% CI = 57-78.6) of sound and carious teeth, respectively, (P = 0.001). Gap/RDT was associated with RA (P < 0.001). Sensitivity, specificity, predictive positive values (PPV), predictive negative value, and accuracy for carious teeth were 77.1% (95% CI = 63.7-87.3), 54.5% (95% CI = 33.8-74.1), 78.7% (95% CI = 65.3- 88.7), 52.2% (95% CI = 32.1-71.7), and 70% (95% CI = 58.5-79.8), and for sound teeth were 73.7% (95% CI = 62.9-82.6), 59.1% (95% CI = 47.0-70.4), 67.5% (95% CI = 56.9-76.9), 66.1% (95% CI = 53.4-77.3), and 66.9% (95% CI = 58.9-74.3). Only the PPV differed between the sound and carious teeth (P = 0.024).There was a correlation between radiolucency and gap/RDT, but a high number of false positives were found.

Three-rooted premolar analyzed by high-resolution and cone beam CT.

OBJECTIVES: The aim of this study was to analyze the variations in canal and root cross-sectional area in three-rooted maxillary premolars between high-resolution computed tomography (µCT) and cone beam computed tomography (CBCT). MATERIALS AND METHODS: Sixteen extracted maxillary premolars with three distinct roots and fully formed apices were scanned using µCT and CBCT. Photoshop CS software was used to measure root and canal cross-sectional areas at the most cervical and the most apical points of each root third in images obtained using the two tomographic computed (CT) techniques, and at 30 root sections equidistant from both root ends using µCT images. Canal and root areas were compared between each method using the Student t test for paired samples and 95 % confidence intervals. RESULTS: Images using µCT were sharper than those obtained using CBCT. There were statistically significant differences in mean area measurements of roots and canals between the µCT and CBCT techniques (P < 0.05). Root and canal areas had similar variations in cross-sectional µCT images and became proportionally smaller in a cervical to apical direction as the cementodentinal junction was approached, from where the area then increased apically. CONCLUSION: Although variation was similar in the roots and canals under study, CBCT produced poorer image details than µCT. CLINICAL RELEVANCE: Although CBCT is a strong diagnosis tool, it still needs improvement to provide accuracy in details of the root canal system, especially in cases with anatomical variations, such as the three-rooted maxillary premolars.

Bibliometric analysis and diagnostic efficacy of cone-beam computed tomography studies published in Imaging Science in Dentistry from 2011 to 2022.

Purpose: This bibliometric analysis aimed to provide a comprehensive overview of the characteristics, trends, and level of diagnostic efficacy of studies on cone-beam computed tomography (CBCT) published in Imaging Science in Dentistry (ISD) from 2011 to 2022. Materials and Methods: Publications related to CBCT identified in the electronic collection of ISD were selected according to eligibility criteria by 2 independent reviewers who collected data on the characteristics of the articles (year, authors, and country). The type and topic of studies were analyzed using VOSviewer v.1.6.18 (Centre for Science and Technology Studies, Leiden University, Leiden, Netherlands). The research articles were classified according to the hierarchical scale of diagnostic efficacy. Results: Of the 236 articles included, most were from South Korea and Brazil. Bong-Hae Cho and Yun-Hoa Jung were the most prolific authors on the topic of CBCT. The most frequently published types of studies were cross-sectional and laboratory-based. The most popular topics WERE related to the diagnosis of pathologies and/or alterations, as well as anatomical variations. On the diagnostic efficacy scale, most studies were rated level 1 (technical efficacy) or 2 (diagnostic accuracy efficacy). Conclusion: A steady increase was observed in publications related to CBCT, which are of both clinical and academic interest. The trends in these publications were analyzed, revealing that most are cross-sectional studies primarily exploring the capabilities of CBCT in diagnosing pathologies and/or changes in the oral and maxillofacial complex. These studies were typically classified as level 1 or 2 on the diagnostic efficacy scale.

Consensus for teaching dental caries in the Portuguese Language at Brazilian dental schools.

The aim of this paper was to present a summary of the process of developing and preparing the final documents of the national consensus for teaching undergraduate Brazilian dental students the dental caries curriculum in the Portuguese language. The final document was developed in three steps: a) The ABENO and LAOHA cariology group invited experts from all five regions of Brazil to participate in the discussion. The theoretical support for crafting the first draft of the consensus was based on two publications: National Curriculum Guidelines of the Dentistry graduation in Brazil, Ministry of Education (2021) and the competences described in the European Core Curriculum for Cariology (ORCA-ADEE, 2011); b) The group of experts was divided into 5 working groups: G1-Domain, Main and Specific Competences, G2-Essential knowledge, G3-Life course perspective, G4-Social determinants and dental caries, G5- Glossary. The document was finalized by thoroughly reviewing the process using Delphi methodology; c) The 5-chapter document (one from each working group) was submitted to three open public consultations in 2022 (May-June, August, and October) using Google-forms. The suggestions (content/wording) were discussed within the group as: totally accepted, partially accepted, and rejected. A total of 192 suggestions were registered from 31 dental schools in all regions of Brazil. The number of suggestions received per Group were: 84, 28, 26, 24, 30 suggestions for G1, G2, G3, G4 and G5, respectively. The majority of suggestions were totally accepted by the group of experts (n = 172, 89.6%), 15 were partially accepted (7.8%), and 5 were rejected. Conclusion The final document could be considered to be the first national consensus for teaching the dental caries curriculum in Brazil.

Azithromycin as an adjunctive treatment of aggressive periodontitis: radiographic findings of a 12-month randomized clinical trial.

PURPOSE: To compare the 12-month radiographic outcomes following the use of azithromycin or placebo as adjuncts to non-surgical periodontal treatment of AgP. METHODS: 17 aggressive periodontitis (AgP) subjects 13-26 years old were randomly assigned to receive scaling and root planing (SRP) with systemic azithromycin or placebo. Standardized radiographs were taken at baseline and 12 months postoperatively. Recall visits consisting of oral prophylaxis and oral hygiene instructions were performed during the 12 months. Digital image subtraction analysis and linear bone measurements were conducted by a blinded and calibrated examiner. Student t-tests were used for within and between-groups comparisons. ANCOVA was applied for between-group comparisons of changes in linear bone level adjusting for baseline values. RESULTS: There were significant gains in linear bone levels in the azithromycin (0.55 +/- 0.10 mm) and placebo (0.42 +/- 0.07 mm) groups between the baseline and 12-month postoperative visits. There were also significant gains in bone density in the two treatment groups. No significant differences were observed between the two treatments in the amount of linear bone gain or bone density during the follow-up period. The use of azithromycin as an adjunct to SRP in the treatment of AgP did not result in significant radiographic bone level changes compared to placebo.

Vertical alveolar growth in subjects with infraoccluded mandibular deciduous molars.

INTRODUCTION: Our objective was to compare vertical alveolar growth in areas adjacent to infraoccluded deciduous molars with growth in areas of deciduous molars and normal occlusion for a period of at least 1 year by using digital subtraction radiography. METHODS: This case-control study included 40 pairs of panoramic radiographs of growing patients with infraoccluded deciduous molars and 40 pairs of radiographs of patients without infraoccluded deciduous molars. One radiograph at baseline was obtained at diagnosis, and the other at least 1 year later. The subjects and the controls were matched according to chronologic age and time interval between the 2 radiographs. The 2 groups were compared with regard to vertical alveolar growth and vertical tooth movement. Measurements were assessed by using nonparametric tests (Mann-Whitney and Friedman) and a multiple comparison test. Significance was set at 5%. RESULTS: A statistically significant difference was observed between the groups with regard to vertical alveolar growth measured on the bone crest between the first permanent molars and second premolars. CONCLUSIONS: Vertical alveolar growth between the first permanent molar and the second premolar adjacent to the infraoccluded teeth was smaller than in areas adjacent to teeth with normal occlusion.

Loss of dental tissue after restoration or sealing of occlusal carious lesions: 3-4-year results of randomized clinical trials.

Context: Although preservation of the tooth structure is quoted as the main advantage of sealing of carious lesions, there are no long-term studies comparing the maintenance of dental tissue after restoration or after caries sealing. Aim: To measure the radiographically visible loss of dental tissue after conventional restoration and sealing of carious lesions. Subjects and Methods: This study was a secondary analysis of two randomized controlled clinical trials, one conducted in Brazil and another in Belgium, which evaluated two different therapies for the treatment of occlusal carious lesions in permanent teeth: sealant (SE) without previous carious tissue removal or restoration (RE) with total removal of carious dentin. The greater depth and width of sealed carious lesions and restorations were compared. Statistical Analysis: The independent t-test was used to compare therapies at different time points, while the paired t-test was used to compare the same therapy over time. Results: Carious lesions in the RE and SE groups showed similar measurements at baseline (P > 0.05). Over time, significantly greater loss of tooth structure was observed in the RE group than in the SE group. No increase in lesion depth or width was observed in the SE group, suggesting no progression of sealed lesions. Conclusion: Sealing of carious lesions resulted in greater preservation of dental tissue.

XP Endo Finisher-R and PUI as supplementary methods to remove root filling materials from curved canals.

This study assessed the ability of XP-endo Finisher R (FKG, La Chaux-de-Fonds, Switzerland) to remove filling remnants from curved mesiobuccal canals of maxillary molars, using the passive ultrasonic irrigation (PUI) technique as a comparison. Twenty-four curved main mesiobuccal canals (MB1) of maxillary molars were instrumented with Wave One (#25/07) and filled with gutta-percha points and AH Plus Sealer. Samples were then re-treated with a standardized protocol with Wave One (#35/06) as the master apical file. Micro-CT scans measured baseline volume of remaining filling material (in mm3). Samples were divided into two groups (n = 12) according to the supplementary cleaning approach: (PUI) or XP-endo Finisher R. Statistics compared baseline and final volume of filling material (within-group); and the percentage of filling material reduction (between-group). Mean baseline volumes, final volumes, and percentages of reduction (%) of filling material for XP-endo Finisher R and PUI were respectively: 0.060 mm3, 0.042 mm3, and 31.28%; and 0.064 mm3, 0.054 mm3, and 16.57%. Both tested protocols reduced the amount of filling material (p < 0.05). XP-endo Finisher R had higher percentage of reduction as compared to PUI (p < 0.05). XP-endo Finisher R and PUI used as supplementary cleaning protocols during re-treatment improved the removal of root filling material in curved canals; but XP-endo Finisher R was approximately twice more efficient. The complete filling material removal during re-treatment procedures is still a challenge. Supplementary cleaning protocols may help to remove the remaining material after the complete mechanical preparation of curved canals. XP-endo Finisher R was approximately twice more efficient than PUI.

Physicochemical properties of three bioceramic cements.

This study aimed to compare the physicochemical properties of MTA Angelus (MTA-A), MTA Repair HP (MTA-HP), and Biodentine (BD). Setting times (n = 7) were determined in accordance with ASTM C266-15. Solubility (n = 11), pH (n = 10), and calcium ion release (n = 10) were evaluated up to 28 days in accordance with ANSI/ADA specification no. 57. Radiopacity was assessed by ANSI/ADA (n = 10) and the tissue simulator method (n = 10). In both methods, the specimens were radiographed using an aluminum stepwedge and the digital radiographs were analyzed in Adobe Photoshop, determining the mean grayscale pixel values of the materials, of the 3-mm aluminum stepwedge, and of the dentin, the latter of which was analyzed on the tissue simulator. The data obtained from each test were statistically analyzed and compared (p < 0.05). MTA-A presented longer final setting time compared with the other materials. There were no significant differences in the mass values of materials during the experiment. All materials presented an alkaline pH. BD promoted greater calcium ion release in most of the experimental periods. All materials presented appropriate radiopacity. BD showed lower radiopacity than MTA-A in the tissue simulator method. All groups presented higher radiopacity in the tissue simulator when compared with the ANSI/ADA method. MTA-A, MTA-HP, and BD showed appropriate physicochemical properties and radiopacity, and were considered suitable to be used in clinical practice.

Diagnostic accuracy of oximetry for obstructive sleep apnea: a study on older adults in a home setting.

OBJECTIVES: Owing to the fact that obstructive sleep apnea (OSA) is an underreported disease, the strategy used for the diagnosis of OSA has been extensively dissected to devise a simplified process that can be accessed by the public health services. Polysomnography (PSG) type I, the gold standard for the diagnosis of OSA, is expensive and difficult to access by low-income populations. In this study, we aimed to verify the accuracy of the oxyhemoglobin desaturation index (ODI) in comparison to the apnea-hypopnea index (AHI) using a portable monitor. METHODS: We evaluated 94 type III PSG home test results of 65 elderly patients (69.21±6.94 years old), along with information, such as the body mass index (BMI) and sex, using data obtained from a clinical trial database. RESULTS: A significant linear positive correlation (r=0.93, p<0.05) was observed between ODI and AHI, without any interference from sex, BMI, and positional component. The sensitivity of ODI compared to that of AHI increased with an increase in the severity of OSA, while the specificity of ODI in comparison to that of AHI was high for all degrees of severity. The accuracy of ODI was 80.7% for distinguishing between patients with mild and moderate apnea and 84.4% for distinguishing between patients with moderate and severe apnea. CONCLUSION: The ODI values obtained in uncontrolled conditions exhibited high sensitivity for identifying severe apnea compared to the AHI values, and correctly identified the severity of OSA in more than 80% of the cases. Thus, oximetry is promising strategy for diagnosing OSA.

The unplanned and unequal expansion of Dentistry courses in Brazil from 1856 to 2020.

This study analyzed the consequences of the disordered expansion of Dentistry courses on the distribution of professionals, the job market, and limitations of the National System of Higher Education Assessment (SINAES) developed as a guarantee of education quality. This observational, descriptive, and analytical study used secondary data from several official databases. The number of courses was obtained from the e-MEC registry. From the Higher Education Census, the study collected historical series of courses offered, number of candidates per open seat, number of individuals who initiated and completed the course, and information about professors in the public and private schools. The reports related to Dentistry courses from the National Health Council were also analyzed. The performance of undergraduate students was assessed from synthesis reports of Enade from 2004 to 2016. The number of dentists and their regional distribution was based on the Federal Dental Council, and Brazilian population and gross domestic product were collected from the Brazilian Institute of Geography and Statistics. Dentistry courses in Brazil grew exponentially from 1856 to 2020; among the 544 authorized courses, 82 currently have not yet started their activities. The fast expansion of courses in Brazil has worsened the regional asymmetries in the supply of dentist, and the SINAES has not been able to fully assure the quality of Dentistry courses. Brazilian dentistry, which has increased its scientific and technological development since the 19th century, with outstanding intellectual production, is at risk of a collapse due to a plethora of dentists.

In vitro evaluation of a method for obtaining periapical radiographs for diagnosis of external apical root resorption.

This in vitro study was conducted to evaluate a method to obtain reproducible periapical radiographs, using individualized positioning devices, of upper central incisors submitted to simulated orthodontic movement. Linear measurements of tooth length were carried out on 29 extracted human central incisors. The teeth were radiographed in a tissue simulator, at different inclinations in the bucco-lingual direction (0 initial, 0 control, -10, -5, +5, and +10 degrees). The radiographs were digitized and quantitative analysis of tooth length was carried out using an electronic ruler. The linear measurements of tooth length were reproducible (r = 0.99) for repeated measurements as well as in the comparison of the initial and control images at 0 degree, where measurements did not differ significantly (analysis of variance, P = 0.827) in radiographs with different angulations. These results show that the method proposed for obtaining in vitro periapical radiographs results in reproducible images of tooth length, even when orthodontic movement is simulated by inclination of the tooth up to 20 degrees in the bucco-lingual direction.

Consensus for teaching dental caries in the Portuguese Language at Brazilian dental schools

Abstract The aim of this paper was to present a summary of the process of developing and preparing the final documents of the national consensus for teaching undergraduate Brazilian dental students the dental caries curriculum in the Portuguese language. The final document was developed in three steps: a) The ABENO and LAOHA cariology group invited experts from all five regions of Brazil to participate in the discussion. The theoretical support for crafting the first draft of the consensus was based on two publications: National Curriculum Guidelines of the Dentistry graduation in Brazil, Ministry of Education (2021) and the competences described in the European Core Curriculum for Cariology (ORCA-ADEE, 2011); b) The group of experts was divided into 5 working groups: G1-Domain, Main and Specific Competences, G2-Essential knowledge, G3-Life course perspective, G4-Social determinants and dental caries, G5- Glossary. The document was finalized by thoroughly reviewing the process using Delphi methodology; c) The 5-chapter document (one from each working group) was submitted to three open public consultations in 2022 (May-June, August, and October) using Google-forms. The suggestions (content/wording) were discussed within the group as: totally accepted, partially accepted, and rejected. A total of 192 suggestions were registered from 31 dental schools in all regions of Brazil. The number of suggestions received per Group were: 84, 28, 26, 24, 30 suggestions for G1, G2, G3, G4 and G5, respectively. The majority of suggestions were totally accepted by the group of experts (n = 172, 89.6%), 15 were partially accepted (7.8%), and 5 were rejected. Conclusion The final document could be considered to be the first national consensus for teaching the dental caries curriculum in Brazil.

Nuclear changes in tongue epithelial cells following panoramic radiography.

This study aimed to investigate the effect of radiation from panoramic radiographs on the cells of the lateral border of the tongue by evaluating nuclear changes. Forty-two patients were included: 22 had one radiograph (Group I), and 20 required a repeat radiograph due to error in the first exposure (Group II). Material for the cytopathologic evaluation was collected before radiographs and 10 days later. Smears were stained with the Feulgen reaction and micronuclei, buds, broken eggs, karyorrhexis and binucleate cells were scored. The comparison of nuclear changes before and after radiation exposure in both groups revealed a statistically higher number of broken eggs, buds, karyorrhexis and binucleate cells 10 days after exposure (P=0.01). The number of karyorrhexis and binucleate cells was greater in group II (P=0.01). There was no change in the frequency of micronuclei before and after the radiographs. Radiation emitted during panoramic radiographs increased the number of nuclear anomalies (except micronuclei) in exfoliated cells of the lateral border of the tongue. This effect was more pronounced when the patients were exposed to a repeat radiograph, without however implying increased risk of irreversible tissue damage.

Canal transportation after root canal instrumentation: a comparative study with computed tomography.

This in vitro study used computed tomography (CT) to compare the occurrence of canal transportation in the apical third of mesiobuccal canals in maxillary molars instrumented with 3 techniques. Sixty teeth were assigned to 3 groups (n = 20), and the root canals were instrumented as follows: Group 1, hand instrumentation with K-files; Group 2, K-files coupled to an oscillatory system powered by an electric engine; Group 3, ProTaper NiTi rotary system powered by an electric engine. To compare the canal transportation produced by the different techniques, preinstrumentation and postinstrumentation 3-dimensional CT images were obtained from root cross-sections of the region located 3 mm short of the apical foramen of each root canal. The CT scans were exported to Adobe Photoshop software, and the initial and final images were superimposed to detect the root canal wall differences between them. Canal transportation was measured by the distance between the prepared canal center and the anatomic canal center. The manual technique produced lesser canal transportation (0.10 mm) than the oscillatory and rotary techniques (0.37 and 0.22 mm, respectively); this difference was statistically significant (P=.021). All studied techniques produced canal transportation.

The role of psychoneuroimmune interactions in the pathogenesis of ligature-induced periodontal disease in Wistar rats.

The aim of the present study was to determine the role of chronic stress in the pathogenesis of ligature-induced periodontal disease in rats. Fifty-three Wistar rats were randomly assigned to 4 experimental groups: 1--ligature; 2--ligature + stress; 3--stress only; 4--control. After 30 days the animals were sacrificed, blood samples were collected and histological sections were made for histometric analysis. The stress parameters evaluated were weight of thymus, spleen, adrenal glands and plasma glucocorticoid levels. Analysis of adrenal glands showed statistically significant differences between stressed and non-stressed groups (one-way ANOVA, p < 0.05). Plasma glucocorticoid levels were higher in Group 3 and lower in Group 2 (81.1 nmol/I versus 62.5 nmol/l, p < 0.05). Histometric measurements from the bone crest and from the first attached fiber were taken for all groups and for Groups 1 and 2 for the sites with and without ligatures. The ligature sites always displayed higher mean values than non-ligated sites (paired sample t test, p < 0.05). No statistically significant differences were observed between Groups 1 and 2 with regard to the ligated sites. However, differences were observed between Groups 1 and 2 in histometric bone levels in the non-ligated sites (mean values of 0.81 and 0.55 mm, respectively, p < 0.05). It may be concluded that stress can have a possible role in the activation of the hypothalamus-pituitary-adrenal (HPA) axis, with different levels of glucocorticoid release.

Apical Transportation, Centering Ratio, and Volume Increase after Manual, Rotary, and Reciprocating Instrumentation in Curved Root Canals: Analysis by Micro-computed Tomographic and Digital Subtraction Radiography.

INTRODUCTION: This study aimed to evaluate apical transportation (AT), centering ratio (CR), and volume increase (VI) produced after instrumentation of mesiobuccal canals of maxillary molars with hand files, rotary, and reciprocating instruments using micro-computed tomographic (micro-CT) imaging and to demonstrate the ability of digital subtraction radiography (DSR) to evaluate AT. METHODS: Forty-five canals were randomly assigned to either group K, manual K-files; PTN, ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland); or Rec, Reciproc (n = 15 for each group) for preparation. Master apical files were #25, X2 (#25/06), and R25 (#25/08), respectively. Micro-CT imaging was used to measure AT (mm) and CR (mm) at 3 different locations (1, 4, and 7 mm from the apex). VI (mm3) was measured for each root third and for the whole canal. DSR (mesiodistal and buccolingual projections) was used to measure AT at 1 mm from the apex. RESULTS: AT and CR values were statistically similar across the groups at 1, 4, and 7 mm. AT results obtained for the different locations were similar within each group; CR, in turn, showed statistically lower values at 1 mm. VI was statistically similar in all groups. Both DSR and micro-CT imaging showed that AT always occurred on the outside of canal curvature. The highest mean value obtained for AT was 0.215 mm. CONCLUSIONS: AT, CR, and VI were similar for the K, PTN, and Rec groups. AT results were clinically irrelevant. DSR was as effective as micro-CT imaging in AT analysis and could be considered as an alternative method for assessing this outcome.

Radiopacity Evaluation of Gutta-Percha Points in Thinner Samples than the ANSI/ADA Recommendation.

The aim of this study was to evaluate the radiopacity of different gutta-percha points (Endo Points®, Dentsply®, Tanari®, Meta®, Roeko® and Odous®) in samples of 1 mm thick as established by ANSI/ADA Specification #57 and ISO 6876/2001, in comparison with thinner samples. Twelve test specimens for each material, four for each thickness (0.3, 0.6, and 1 mm and diameter of 8 mm), were laminated and compressed between two polished glass plates until the desirable thickness. Digital radiographs were obtained along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The X-ray unit was set at 70 kVp, 10 mA and 0.4 s exposure time, at a focal distance of 36 cm. One calibrated observer quantified the average values of pixels with Adobe Photoshop® software. Data were analyzed using ANOVA and Tukey tests, at 5% significance level. At 0.6 and 1 mm thickness, all the tested materials showed radiopacity higher than 3 mm of aluminum (reference value). At 0.3 mm thickness, Odous and Tanari presented significantly less radiopacity than the reference, and the other materials showed similar radiopacity to the reference. The study concluded that the materials demonstrated different radiopacities and all had values above the minimum recommended by ANSI/ADA specification #57, being Odous and Tanari less radiopaque than the reference value in thinner samples (0.3mm).