Can maxillary molar dimensions predict the presence of the second mesiobuccal canal?

OBJECTIVE: To evaluate the potential of maxillary molar dimensions as predictors of the presence of the second mesiobuccal (MB2) canal. METHODS: Micro-computed tomography scans were obtained from 47 maxillary molars, out of which 26 had the MB2 canal. The distance between root canals, extension of the canals, and thickness of surrounding dentin were obtained from axial images at the furcation level, 3 mm from the apex, and 5 mm from the apex. The association between the measurements and the presence of the MB2 canal was assessed using multiple logistic regression and odds ratio. RESULTS: At the furcation level, the bucco-palatal extension of the MB1 canal significantly decreased the chance of the presence of the MB2 canal. Regarding the thickness of surrounding dentin measurements, the mesial and distal aspects of the MB1 canal at 3 mm from the apex were statistically significant to decrease and increase the chance of presence of the MB2 canal, respectively. Regarding the extension of the canals, only buccal-palatal extension seems to decrease the chance of the presence of the MB2 canal. CONCLUSION: The presence of the MB2 canal in the mesiobuccal root of maxillary molars is associated with the bucco-palatal extension and surrounding dentin thickness of the first mesiobuccal canal, and seems to be unrelated to the dimensions of the distobuccal and palatal roots.

Can the detection of second mesiobuccal canals be enhanced based on the volume of adjacent canals?

OBJECTIVES: The purpose of this study was to evaluate whether the presence of the second mesiobuccal (MB2) canal is related to volumetric differences on the adjacent canals of maxillary molars. DESIGN: Forty-seven maxillary first and second molars with and without the MB2 canal were individually scanned using microcomputed tomography (micro-CT). The volume of each canal was measured by an evaluator with experience in micro-CT analysis. The intraclass correlation coefficient (ICC) was obtained. Multiple logistic regression and odds ratio was calculated. To compare the volume of canals in molars with and without MB2, the Mann-Whitney test was applied (α = 0.05). RESULTS: The intra-examiner reproducibility was almost perfect (ICC=0.97). Multiple logistic regression demonstrated that the volume of the mesiobuccal (MB1) canal can possibly act as a predictor of the presence of the MB2 canal. It was also found that the MB1 canal volume is larger in molars without the MB2 canal (p = 0.01). No statistically significant difference was observed in the adjacent canals (p > 0.05). CONCLUSIONS: Despite the challenging detection of the presence of MB2 canals, clinicians should be aware that MB1 canals of reduced volume are highly suggestive of their presence.

Optimal Parameters of Laser Therapy to Improve Critical Calvarial Defects.

Body bones play diverse pivotal roles, including the protection of vital organs. For instance, the integrative functions of the brain controlling diverse peripheral actions can be affected by a traumatic injury on the calvaria and the reparative process of a large defect is a challenge in the integrative physiology. Therefore, the development of biomaterials and approaches to improve such defects still requires substantial advances. In this regard, the most attractive approaches have been covering the cavity with inorganic bovine bone (IBB) and, more recently, also using low-level laser therapy (LT), but this issue has opened many questions. Here, it was determined the number of LT sessions required to speed up and to intensify the recovery process of two 5-mm-diameter defects promoted in the calvaria of each subgroup of six adult Wistar rats. The quantitative data showed that 30 days post-surgery, the recovery process by using blood clot-filling was not significantly influenced by the number of LT sessions. However, in the IBB-filled defects, the number of LT sessions markedly contributed to the improvement of the reparative process. Compared to the Control group (non-irradiated), the percentage of mineralization (formation of new bone into the cavities) gradually increased 25, 49, and 52% with, respectively, 4, 7, and 11 sessions of LT. In summary, combining the use of IBB with seven sessions of LT seems to be an optimal approach to greatly improve the recovery of calvarial defects. This translational research opens new avenues targeting better conditions of life for those suffering from large bone traumas and in the present field could contribute to preserve the integrative functions of the brain.

Morphological characteristics of the mesiobuccal root in the presence of a second mesiobuccal canal: a micro-CT study.

Objectives: This study investigated the internal morphology of mesiobuccal (MB) roots of maxillary molars with a second mesiobuccal (MB2) canal. Materials and Methods: Forty-seven maxillary first or second molars from Brazilians were scanned using micro-computed tomography. The following measurements were obtained from the MB roots: root thickness, root width, and dentin thickness of the buccal aspect of the first mesiobuccal (MB1) canal, between the MB1 and MB2 canals, and the palatal aspect of the MB2 and MB1 canals at 3 mm from the root apex and in the furcation region. For statistical analysis, the Student's t-test and analysis of variance with the post-hoc Tukey test were used (α = 0.05). Results: In maxillary molars with an MB2 canal, MB roots were significantly thicker (p = 0.0014) and narrower (p = 0.0016) than in maxillary molars without an MB2 canal. The dentin thickness of the palatal aspect of the MB1 canal was also significantly greater than that of MB roots without an MB2 canal at 3 mm from the root apex (p = 0.0007) and in the furcation region (p < 0.0001). In the furcation region of maxillary molars with an MB2 canal, the dentin thickness between the MB1 and MB2 canals was significantly smaller than that in the buccal and palatal aspects (p < 0.0001). Conclusions: The internal morphology of MB roots of maxillary molars with an MB2 canal revealed differences in dentin thickness, root diameter, and distance between the canals when compared with maxillary molars without an MB2 canal.

Validity of micro-CT for in vitro caries detection: a systematic review and meta-analysis.

OBJECTIVE: To investigate the validity of micro-CT for in vitro caries detection in comparison with histology as the reference standard. METHODS: A systematic search was conducted in the databases Latin American and Caribbean Health Sciences (LILACS), LIVIVO, PubMed, Scopus and Web of Science from their inception to 16 January 2019. Grey literature was searched on Open Grey, ProQuest Dissertations and Theses Database and Google Scholar. In vitro studies assessing the validity of micro-CT for caries detection were included when compared with histology as the reference standard were included. Two authors independently collected the information and sensitivity, specificity, positive and negative likelihood ratios, as well as diagnostic odds ratios were calculated. The risk of bias of the included studies was assessed using the QUADAS-2 tool. Certainty of evidence was assessed with GRADE. RESULTS: A total of 270 papers were identified, and after a 2-phase selection, 12 studies were included in qualitative and three in quantitative synthesis. For enamel caries diagnostic, sensitivity values ranged from 29.0 to 84.0% indicating high variability while specificity varied from 88.0 to 95.0% indicating good to excellent micro-CT capability do identify the true negative. For dentine caries diagnostic, sensitivity values ranged from 61.0 to 77.0% indicating fair-to-good probability of micro-CT to identify the true positives, while specificity varied from 88.0 to 94.0%. The majority of the included studies presented low risk of bias and moderate certainty of evidence. CONCLUSIONS: This study demonstrated the validity of micro-CT for in vitro caries detection in comparison with histology.

Beam hardening correction tool improves the diagnosis of incipient caries lesions in Micro-CT images.

OBJECTIVE: To evaluate the effect of Beam Hardening Correction tool (BHC) on Micro-CT images used in the diagnosis of incipient caries lesions. METHODS: Six posterior teeth, with 6 sound proximal surfaces and 6 natural white spot lesions, were scanned using a SkyScan1174 device. Each tooth was imaged 16 times in various acquisition parameters, and reconstructed 3 times applying different levels of BHC (0, 15 and 30%). The 288 datasets were analyzed by three examiners. Gold-standard was obtained by microscopic analyses under polarized light. Area under the ROC curve was obtained for each protocol and the BHC parameter was isolated to individually observe the influence of such parameters of reconstruction. RESULTS: Microtomographic images were accurate for the diagnosis of incipient caries lesions even when the BHC tool was not applied. Accuracy was perfect in 50 % of the protocols without BHC. When adding the artefact correction, the number of protocols that reached perfect accuracy increased to 81.25%. No difference was found between the protocols that used 15 or 30% BHC. Statistically significant differences were found only in four comparisons, and on those the images that had BHC were more accurate. Two non-BHC protocols reached accuracy scores of 0.653 and 0.881, and were improved to perfect accuracy with BHC application. CONCLUSION: The use of the BHC tool should be encouraged when using Micro-CT to detect incipient caries lesions, especially when low-quality parameters aiming less acquisition and processing time are used.

Segmentation Methods for Micro CT Images: A Comparative Study Using Human Bone Samples.

X-ray microtomography (microCT) is a nondestructive technique used to assess bone morphometry. For an accurate analysis, it is necessary to segment the bone tissue from the background images, avoiding under- or overestimation of the real bone volume. Thus, segmentation methods for microCT can influence the accuracy of bone morphometry analysis. The purpose of this study was to compare two different image segmentation methods available on microCT software (subjective and objective) regarding to the human bone morphometric analysis. Sixteen samples containing a fixation screws covered by 0.5-1mm of bone were scanned using the SkyScan 1173 scanner. Three examiners segmented the microCT images subjectively and recorded the threshold values. Subsequently, an objective segmentation was also done. The 3D analysis was performed for both images using the values​ previously determined in CTAn software. Five bone morphometric parameters were calculated (BV/TV, Tb.Th, Tb.N, Tb.Sp, Conn.Den) and used as dependent variables. ANOVA showed no significant differences between the methods concerning BV/TV (p=0.424), Tb.N (p=0.672), Tb.Th (p=0.183), Tb.Sp (p=0.973) and Conn.Den (p=0.204). Intra- and interobserver agreement ranged from satisfactory to excellent (0.55-1 and 0.546-0.991, respectively). Therefore, results obtained with subjective threshorlding were similar to those obtained with objective segmentation. Since objective segmentation does not have human input and it is a truly objective method, it should be the first choice in microCT studies that concern homogeneity and high resolution human bone sample.

Feasibility of micro-computed tomography to detect and classify proximal caries lesions in vitro.

BACKGROUND: Micro-computed tomography (micro-CT) has been widely described as a nondestructive in vitro imaging method although its accuracy for caries detection is still unclear. The aim of this study was to investigate the feasibility of micro-CT to detect and classify proximal caries lesions in posterior teeth, using different protocols. MATERIALS AND METHODS: In this in vitro study, crowns of 122 human teeth were scanned with Skyscan 1174 (Bruker, Kontich, Belgium) using the full-scan mode (360°). Reconstruction of 900 basis images was performed using NRecon Software (Bruker, Kontich, Belgium) for the protocol 1 (full-scan mode 360°), and 450 basis images were used to reconstruct the protocol 2 (half-scan mode 180°). Three observers analyzed the reconstructed images concerning the presence and depth of proximal caries lesions (244 surfaces). To determine the presence/absence and depth of caries lesions, histological examination was conducted as reference standard level of significance McNemar and McNemar-Bowker tests compared the methods studied and the gold standard (P < 0.05). RESULTS: The intra- and inter-observer agreement for both methods ranged from moderate to excellent. There was no difference between both micro-CT methods and histology for the presence of lesions (P > 0.05). However, both methods differed with the reference standard for depth (P < 0.05). The disagreement occurred mostly in cases of enamel lesions. The highest diagnostic values were found for 180° rotation. Micro-CT performed well in detecting caries lesions compared to histology, meanwhile the classification of their depth presented lower values. Scan mode did not influence the detection. CONCLUSION: Both protocols of micro-CT tested presented an overall satisfactory performance in detecting proximal caries lesions; however, for the depth classification, the method was not accurate.

Comparison of automatic and visual methods used for image segmentation in Endodontics: a microCT study.

OBJECTIVE: To calculate root canal volume and surface area in microCT images, an image segmentation by selecting threshold values is required, which can be determined by visual or automatic methods. Visual determination is influenced by the operator's visual acuity, while the automatic method is done entirely by computer algorithms. To compare between visual and automatic segmentation, and to determine the influence of the operator's visual acuity on the reproducibility of root canal volume and area measurements. MATERIAL AND METHODS: Images from 31 extracted human anterior teeth were scanned with a µCT scanner. Three experienced examiners performed visual image segmentation, and threshold values were recorded. Automatic segmentation was done using the "Automatic Threshold Tool" available in the dedicated software provided by the scanner's manufacturer. Volume and area measurements were performed using the threshold values determined both visually and automatically. RESULTS: The paired Student's t-test showed no significant difference between visual and automatic segmentation methods regarding root canal volume measurements (p=0.93) and root canal surface (p=0.79). CONCLUSION: Although visual and automatic segmentation methods can be used to determine the threshold and calculate root canal volume and surface, the automatic method may be the most suitable for ensuring the reproducibility of threshold determination.

Comparison of automatic and visual methods used for image segmentation in Endodontics: a microCT study

Abstract To calculate root canal volume and surface area in microCT images, an image segmentation by selecting threshold values is required, which can be determined by visual or automatic methods. Visual determination is influenced by the operator's visual acuity, while the automatic method is done entirely by computer algorithms. Objective: To compare between visual and automatic segmentation, and to determine the influence of the operator's visual acuity on the reproducibility of root canal volume and area measurements. Material and methods: Images from 31 extracted human anterior teeth were scanned with a μCT scanner. Three experienced examiners performed visual image segmentation, and threshold values were recorded. Automatic segmentation was done using the "Automatic Threshold Tool" available in the dedicated software provided by the scanner's manufacturer. Volume and area measurements were performed using the threshold values determined both visually and automatically. Results: The paired Student's t-test showed no significant difference between visual and automatic segmentation methods regarding root canal volume measurements (p=0.93) and root canal surface (p=0.79). Conclusion: Although visual and automatic segmentation methods can be used to determine the threshold and calculate root canal volume and surface, the automatic method may be the most suitable for ensuring the reproducibility of threshold determination.

Influence of Artifact Reduction Tools in Micro-computed Tomography Images for Endodontic Research.

INTRODUCTION: Micro-computed tomography (µCT) is an imaging modality of growing application in endodontic research because of its nondestructive technology that enables visualization at the micrometer level. In the presence of high-density material, images acquired with µCT may present artifacts. Thus, the aim of this study was to evaluate subjectively and objectively the influence of artifact reduction tools available for µCT image reconstruction to determine whether their use can influence endodontic research outcomes. METHODS: Ten teeth were scanned in a µCT device, and these images were reconstructed by applying 13 protocols of artifact reduction tools, combining ring artifact reduction (RAR) and beam-hardening artifact reduction (BAR). Images were assessed subjectively (observer's preference) and objectively (root canal surface area and volume). Observer's preference for RAR and BAR protocols was tested by χ2. Analysis of variance was used to compare volumes and surface area of root canals on different protocols. Intraobserver and interobserver reproducibility was calculated by the weighted kappa test. RESULTS: There was no preference for a particular protocol for BAR (P = .91) or RAR (P = .80). There were no statistically significant differences for volume (P = .999) or surface area (P = .972) of root canals for all protocols. CONCLUSIONS: To evaluate root canal volume and root canal surface area, artifact reduction tools applied to µCT images can be used according to the observer's visual preference without influence on objective image analysis.

Diagnostic accuracy of phosphor plate systems and conventional radiography in the detection of simulated internal root resorption.

OBJECTIVE: To evaluate the performance of conventional radiography and photostimulable phosphor (PSP) plate in the detection of simulated internal root resorption (IRR) lesions in early stages. MATERIALS AND METHODS: Twenty single-rooted teeth were X-rayed before and after having a simulated IRR early lesion. Three imaging systems were used: Kodak InSight dental film and two PSPs digital systems, Digora Optime and VistaScan. The digital images were displayed on a 20.1″ LCD monitor using the native software of each system, and the conventional radiographs were evaluated on a masked light box. Two radiologists were asked to indicate the presence or absence of IRR and, after two weeks, all images were re-evaluated. Cohen's kappa coefficient was calculated to assess intra- and interobserver agreement. The three imaging systems were compared using the Kruskal-Wallis test. RESULTS: For interexaminer agreement, overall kappa values were 0.70, 0.65 and 0.70 for conventional film, Digora Optima and VistaScan, respectively. Both the conventional and digital radiography presented low sensitivity, specificity, accuracy, positive and negative predictive values with no significant difference between imaging systems (p = .0725). CONCLUSIONS: The performance of conventional and PSP was similar in the detection of simulated IRR lesions in early stages with low accuracy.

Brazilian young dental practitioners' use and acceptance of digital radiographic examinations.

PURPOSE: The aim of this study was to investigate the use and acceptance of digital radiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years. MATERIALS AND METHODS: Dental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digital radiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05). RESULTS: A total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digital radiographic examinations, while in 2015 this number increased significantly to 85.4% (p<.0001), out of which 71.4% preferred it to conventional images. Moreover, 21.4% of respondents reported having used digital radiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digital radiographic examinations. CONCLUSION: This study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digital radiographic examinations.

Impact of micronutrients supplementation on bone repair around implants: microCT and counter-torque analysis in rats.

UNLABELLED: The use of natural substances and micronutritional approaches has been suggested as a therapeutic alternative to benefit the bone healing associated with no side effects. Nevertheless, the influence of micronutritional interventions with therapeutic proprieties on the bone repair has yet to be intensely evaluated, and no evidence is available exploring the impact of micronutrient supplementation on the peri-implant bone healing. OBJECTIVE: This study investigated the effect of micronutrients supplementation on the bone repair around implants. MATERIAL AND METHODS: One screw-shaped titanium implant was inserted in each tibia of each rat, which were assigned to: daily administration, for 30 d, of the placebo solution (Placebo group-n:18) or micronutrients supplementation (Micronutrients group-n:18), based on calcium, magnesium, zinc, and vitamin D3 intake. After, the animals were sacrificed. One of the implants was removed by applying a counter-torque force to evaluate the force to rupture the bone-implant interface. The other implant was evaluated by microcomputed tomography (CT) examination to determine the bone-to-implant contact (BIC) and the bone volume (BV/TV). RESULTS: No statistically significant differences were observed between the groups for both counter-torque values and microCT parameters (p>0.05). CONCLUSION: Within the limits of this study, micronutrients supplementation did not provide additional benefits to the bone healing around dental implants.

Impact of micronutrients supplementation on bone repair around implants: microCT and counter-torque analysis in rats

ABSTRACT The use of natural substances and micronutritional approaches has been suggested as a therapeutic alternative to benefit the bone healing associated with no side effects. Nevertheless, the influence of micronutritional interventions with therapeutic proprieties on the bone repair has yet to be intensely evaluated, and no evidence is available exploring the impact of micronutrient supplementation on the peri-implant bone healing. Objective This study investigated the effect of micronutrients supplementation on the bone repair around implants. Material and Methods One screw-shaped titanium implant was inserted in each tibia of each rat, which were assigned to: daily administration, for 30 d, of the placebo solution (Placebo group-n:18) or micronutrients supplementation (Micronutrients group-n:18), based on calcium, magnesium, zinc, and vitamin D3 intake. After, the animals were sacrificed. One of the implants was removed by applying a counter-torque force to evaluate the force to rupture the bone-implant interface. The other implant was evaluated by microcomputed tomography (CT) examination to determine the bone-to-implant contact (BIC) and the bone volume (BV/TV). Results No statistically significant differences were observed between the groups for both counter-torque values and microCT parameters (p>0.05). Conclusion Within the limits of this study, micronutrients supplementation did not provide additional benefits to the bone healing around dental implants.

Effect of low shrinkage monomers on physicochemical properties of dental resin composites.

UNLABELLED: The aim of this study was to evaluate the effect of low shrinkage monomers on physicochemical properties of dental resin composites. Two low shrinkage resin composites: one with a crosslink branching monomer (Kalore, GC Corp) and a novel monomer (Venus Diamond, Heraeus Kulzer) were compared to a conventional resin composite formulation (Filtek Z250, 3M/ESPE). The volumetric shrinkage was evaluated by µCT analysis (n=5) and the physicochemical properties by degree of C=C conversion (DC), flexural strength (FS) and Young's modulus (YM) (n=10). All samples were light cured by a LED device (Radii, SDI) with 16 J/cm2. The results were analysed by one-way ANOVA and Tukey test for multiple comparisons (α=0.05). No statistical difference was found between µCT shrinkage values to Kalore (1.8%) and Venus Diamond (1.7%) (p≥0.05); Z250 presented statistical highest shrinkage value (2.0%). Kalore presented higher statistical DC (60.8%) than Venus Diamond (49.5%) and Z250 (49.6%). No statistical difference was found between FS or YM properties to Venus Diamond and Z250; Kalore presented statistical lowest FS and YM properties (p≥0.05). CONCLUSION: Using novel monomers seem to reduce polymerization shrinkage without affecting the physicochemical properties evaluated of resin composites rather than using crosslink branching monomers.

Effect of Low Shrinkage Monomers on Physicochemical Properties of Dental Resin Composites

The aim of this study was to evaluate the effect of low shrinkage monomers on physicochemical properties of dental resin composites. Two low shrinkage resin composites: one with a crosslink branching monomer (Kalore, GC Corp) and a novel monomer (Venus Diamond, Heraeus Kulzer) were compared to a conventional resin composite formulation (Filtek Z250, 3M/ESPE). The volumetric shrinkage was evaluated by µCT analysis (n=5) and the physicochemical properties by degree of C=C conversion (DC), flexural strength (FS) and Young's modulus (YM) (n=10). All samples were light cured by a LED device (Radii, SDI) with 16 J/cm2. The results were analysed by one-way ANOVA and Tukey test for multiple comparisons (α=0.05). No statistical difference was found between µCT shrinkage values to Kalore (1.8%) and Venus Diamond (1.7%) (p≥0.05); Z250 presented statistical highest shrinkage value (2.0%). Kalore presented higher statistical DC (60.8%) than Venus Diamond (49.5%) and Z250 (49.6%). No statistical difference was found between FS or YM properties to Venus Diamond and Z250; Kalore presented statistical lowest FS and YM properties (p≥0.05). Conclusion: Using novel monomers seem to reduce polymerization shrinkage without affecting the physicochemical properties evaluated of resin composites rather than using crosslink branching monomers.

O objetivo deste trabalho foi avaliar o efeito de monômeros de baixa contração de polimerização nas propriedades físico-químicas de resinas compostas. Duas resinas de baixa contração de polimerização com monômeros do tipo crosslink (Kalore GC Corp) ou do tipo novelar (Venus Diamond Heraeus Kulzer) foram comparadas a uma resina composta convencional (Filtek Z250 3M/ESPE). A contração de polimerização foi avaliada através da análise por µCT (n=5) e as propriedades físico-químicas através da análise do grau de conversão C=C (GC) resistência flexural (RF) e módulo de Young (MY) (n=10). Todas as amostras foram fotoativadas com uma fonte de LED (Radii SDI) com 16 J/cm2. Todos os resultados foram submetidos aos testes de análise de variância de 1 fator e ao teste de Tukey para comparações múltiplas (α=0,05). Nenhuma diferença estatística foi encontrada para os valores de contração de polimerização para Kalore (1,8 %) e Venus Diamond (1,7 %) (p≥0,05). Z250 apresentou estatisticamente maior contração de polimerização (2,0%). Kalore apresentou estatisticamente maior GC (60,8%) que Venus Diamond (49,5%) e Z250 (49,6%). Nenhuma diferença estatística foi encontrada para as propriedades RF e MY entre Venus Diamond e Z250. Kalore apresentou os menores valores estatisticos para FS e MY (p≥0,05). O monômero novelar parece reduzir a contração de polimerização sem afetar as propriedades físico-químicas avaliadas das resinas compostas de forma mais adequada que a utilização de monômeros do tipo crosslinker.

Concrescence: assessment of case by periapical radiography, cone beam computed tomography and micro-computed tomography.

The aim of this article was to describe imaging aspects of concrescence analyzed by three imaging modalities. A second molar joined together with a third molar was imaged using digital periapical radiography, cone beam computed tomography (CBCT) and micro-computed tomography (Micro-CT). On periapical radiograph, the mesial root of the third molar is superimposed on the distal root of the second molar. On CBCT images, a large cementum union between bulbous roots was detected, confirming the diagnosis of concrescence. On micro-CT images, the cementum union appeared limited to the apical third of the roots. In conclusion, both computed tomography modalities allowed for the diagnosis of concrescence. However, only micro-CT provided the real extension of the cementum union.

Enhancement cone beam computed tomography filters improve in vitro periimplant dehiscence detection.

OBJECTIVE: To investigate whether cone beam computed tomography filters would improve periimplant dehiscence detection. STUDY DESIGN: A hundred titanium implants were placed in bovine ribs in which defects simulating periimplant dehiscence had previously been created. After images acquisition, three oral radiologists assessed them with and without the following filters: Angio Sharpen high 5 × 5, Shadow, Sharpen 3 × 3, Sharpen Mild, and Smooth. The McNemar test verified the disagreement between all images versus the reference standard and original images versus images with filters; P < .05 was considered statistically significant. RESULTS: Dehiscence detection using the original images and the Shadow filter disagreed from the reference standard (P < .05), as well as when using the filters instead of the original images (P < .05). CONCLUSION: All the filters tested, with the exception of the Shadow, improved periimplant dehiscence detection. The Sharpen 3 × 3 filter was considered best for this task.

A survey on dental undergraduates' knowledge of oral radiology

Dentists’ incorrect behavior with regards to Oral Radiology, as reported in the literature, has beenrelated to inadequate training of undergraduates. Aim: This study assessed dental undergraduates’knowledge of Oral Radiology. Methods: A questionnaire containing 30 questions pertaining tothree domains - General Principles, Radiobiology/Radioprotection and Technique/Interpretation- was used as data collection instrument. A total of 195 students answered the questionnaires.Results: No statistically significant differences were found between second-, third- and fourthyearstudents (p>0.05) when the whole questionnaire and the General Principles domain (p>0.05)were considered. The Technique/Interpretation domain presented a borderline statistical significancelevel (p=0.051), with more correct answers attributed to second-year students. A statisticallysignificant difference (p<0.05) was seen for the Radiobiology/Radioprotection domain, in whichthe fourth-year students performed better. Conclusions: Dental undergraduates’ knowledge ofOral Radiology did not increase or decrease significantly comparing the undergraduate years.However, with the exception of the Technique/Interpretation domain, students of more advancedundergraduate years answered more correctly the questions. Nevertheless, the Technique/Interpretation domain should be reinforced throughout the undergraduate course.