Agenesia of salivary glands: incidental findings in multidetector computerized tomography.

Agenesis of the salivary glands is an extremely uncommon finding, and in the majority of cases, it is associated with facial syndromes or malformations. Reports in the literature have, however, indicated that agenesis of the major salivary glands can occur in isolation, and this anomaly is believed to occur due to a failure in the developmental process. Herein, we present two cases of isolated unilateral agenesis of major salivary glands.

Invasive cervical resorption of central incisor during orthodontic treatment

ABSTRACT Introduction: Invasive cervical resorption (ICR) is a relatively rare type of ERR (External Root Resorption), in which a localized resorption begins in the cervical area of the tooth, below the epithelial junction and above the ridge crest. Objective: Describe the clinical case of an 11-year-old boy with no dental trauma history, presenting moderate crowding and ectopic eruption of the maxillary right central incisor. He had been undergoing orthodontic treatment elsewhere, and his family was dissatisfied with the results. Description: A new treatment was indicated, which included rapid maxillary expansion followed by extraction of four premolars. During routine panoramic evaluation, a radiolucid image was detected and a periapical radiograph was requested. At this point, an ICR of the maxillary right central incisor was found. The treatment was cautiously finalized and despite the use of light forces, central incisor was severally compromised by ICR and was therefore extracted. Conclusion: This clinical example discusses the importance of routine radiographs for the early diagnoses of ICR.

RESUMO Introdução: A reabsorção cervical invasiva (RCI) é um tipo relativamente raro de reabsorção radicular externa (RRE), no qual uma reabsorção localizada começa na região cervical do dente, abaixo da junção epitelial e acima da crista marginal. Objetivo: Descrever o caso clínico de um menino com 11 anos de idade, sem histórico de trauma dentário, apresentando apinhamento moderado e erupção ectópica do incisivo central superior. Ele realizava tratamento ortodôntico em outro local, mas sua família estava insatisfeita com os resultados. Descrição: Foi iniciado um novo tratamento, que incluiu a expansão rápida da maxila, seguida pela extração de quatro pré-molares. Durante a avaliação de rotina da radiografia panorâmica, uma imagem radiolúcida foi detectada, e uma radiografia periapical da região foi solicitada, sendo encontrada uma RCI no incisivo central superior direito. O tratamento foi finalizado com cautela e, apesar do uso de forças leves, o incisivo central estava seriamente comprometido pela RCI e, portanto, precisou ser extraído. Conclusão: Esse exemplo clínico discute a importância das radiografias de rotina para o diagnóstico precoce da RCI.

Invasive cervical resorption of central incisor during orthodontic treatment.

INTRODUCTION: Invasive cervical resorption (ICR) is a relatively rare type of ERR (External Root Resorption), in which a localized resorption begins in the cervical area of the tooth, below the epithelial junction and above the ridge crest. OBJECTIVE: Describe the clinical case of an 11-year-old boy with no dental trauma history, presenting moderate crowding and ectopic eruption of the maxillary right central incisor. He had been undergoing orthodontic treatment elsewhere, and his family was dissatisfied with the results. DESCRIPTION: A new treatment was indicated, which included rapid maxillary expansion followed by extraction of four premolars. During routine panoramic evaluation, a radiolucid image was detected and a periapical radiograph was requested. At this point, an ICR of the maxillary right central incisor was found. The treatment was cautiously finalized and despite the use of light forces, central incisor was severally compromised by ICR and was therefore extracted. CONCLUSION: This clinical example discusses the importance of routine radiographs for the early diagnoses of ICR.

Correlation between temporomandibular joint morphometric measurements and gender, disk position, and condylar position.

OBJECTIVE: The aim of this study was to correlate the morphometric measurements of the temporomandibular joint, including condylar size, joint space, and articular eminence size, with gender, disk position, and condylar position by using magnetic resonance imaging. STUDY DESIGN: Overall, 93 patients were evaluated (31.2% males and 68.8% females; age 18-81 years; mean age 41 years). Condylar size (D1), joint space (D2), and eminence size (D3) were measured. Correlations with gender, disk position, and condylar position were calculated. RESULTS: A statistically significant correlation was found between D2 and gender, with the joint space being significantly larger in the male group (P = .05). There were correlations between D2 and the position of the disk and the position of the condyle (P ≤ .05). CONCLUSIONS: The results indicate a correlation between male gender and larger joint space. In addition, we found that the joint space size influences the articular disk and condyle position, which can cause disk displacement.

Cisto Odontogênico Ortoceratinizado: Relato de caso / Orthokeratinized Odontogenic Cyst: Case Report

O Cisto Odontogênico Ortoceratinizado (COO) é um cisto de desenvolvimento que ocorre nos maxilares, com maior predileção pela região posterior da mandíbula, em pacientes jovens do gênero masculino. O COO é caracterizado radiograficamente como uma área radiolúcida, unilocular bem definida e identificado histologicamente pela presença de uma cavidade cística fibrosa, revestida por epitélio estratificado pavimentoso ortoceratinizado. O tratamento do COO geralmente conservador, consiste na enucleação associada à curetagem óssea. O objetivo deste trabalho é relatar um caso de COO localizado em mandíbula... (AU)

The Orthokeratinized Odontogenic Cyst (OOC) is a developmental cyst that occurs in the jaws, with a greater predilection in the posterior region of the mandible in young male patients. OOC is characterized radiographically as a well-defined radiolucent, unilocular area and histologically identified by the presence of a fibrous cystic cavity lined by orthokeratinized squamous epithelium. Treatment of OOC is usually conservative and consists of enucleation associated with bone curettage. The objective of this study is to report a case of OOC located in the mandible... (AU)

The effect of different exposure parameters on proximal caries detection using the Kodak 9000 3D CBCT system / Efeito de diferentes parâmetros de exposição na detecção de cáries proximais usando o sistema Kodak 9000 3D TCFC

ABSTRACT Objective: The objective of study was to evaluate the diagnostic quality of CBCT images for caries lesions detection using different exposure parameters. Methods: Sixty extracted human teeth were selected and scanned using Kodak 9000 3D CBCT system, with the following exposure parameters combinations: 74 kV, 10mA; 74 kV, 12mA; 74 kV, 8 mA; 70 kV, 10 mA; 70kV, 12 mA; 70 kV e 8 mA; 70 kV, 6.3 mA. Two observers evaluated the images for caries presence using CS 3D Imaging Software. Each observer scored the proximal surfaces of each tooth on a 5-point scale. The scores were compared to histological sections used as gold standard. Accuracy for caries lesion detection was assessed for each exposure parameter combination and evaluated by means of ROC curve analysis. Results: The mean values for the areas under the ROC curves for each exposure parameter combination varied from 0.35 to 0.60. There was no statistical significant difference among protocols 1, 2, 4, 6 and 7. However, protocols 3 and 5 differed from all protocols. Conclusion: Although the highest dose protocol was the most efficient for proximal caries detection, the lowest dose protocol should be chosen based on the ALADA principle.

RESUMO Objetivo: Avaliar a qualidade de diagnóstico de imagens de TCFC para detecção de lesões de cárie utilizando parâmetros de exposição diferentes. Métodos: Sessenta dentes humanos extraídos foram selecionados e digitalizados usando o sistema Kodak 9000 3D TCFC, com as seguintes combinações de parâmetros de exposição: 74 kV, 10 mA; 74 kV, 12 mA; 74 kV, 8 mA70 kV, 10 mA; 70 kV, 12 mA; 70 kV e 8 mA; 70 kV, 6,3 mA. Dois observadores avaliaram as imagens para a presença de cárie utilizando o CS 3D Imaging Software. Cada observador pontuou as superfícies proximais de cada dente em uma escala de 5 pontos. Os escores foram comparados com cortes histológicos, utilizados como padrão-ouro. A precisão para detecção de lesões de cárie foi analisada para cada combinação de parâmetros de exposição e avaliada por meio de análise da curva ROC. Resultados: Os valores médios para as áreas sob as curvas ROC para cada combinação de parâmetro de exposição variou de 0,35-0,60. Não houve diferença estatística significativa entre os protocolos 1, 2, 4, 6 e 7. No entanto, os protocolos 3 e 5 diferem de todos os protocolos. Conclusão: Embora o protocolo de dose mais elevada foi o mais eficiente para a detecção da cárie proximal, o protocolo de dose mais baixa deverá ser escolhido com base no princípio ALADA.

Quantitative assessment of image artifacts from root filling materials on CBCT scans made using several exposure parameters.

PURPOSE: To quantify artifacts from different root filling materials in cone-beam computed tomography (CBCT) images acquired using different exposure parameters. MATERIALS AND METHODS: Fifteen single-rooted teeth were scanned using 8 different exposure protocols with 3 different filling materials and once without filling material as a control group. Artifact quantification was performed by a trained observer who made measurements in the central axial slice of all acquired images in a fixed region of interest using ImageJ. Hyperdense artifacts, hypodense artifacts, and the remaining tooth area were identified, and the percentages of hyperdense and hypodense artifacts, remaining tooth area, and tooth area affected by the artifacts were calculated. Artifacts were analyzed qualitatively by 2 observers using the following scores: absence (0), moderate presence (1), and high presence (2) for hypodense halos, hypodense lines, and hyperdense lines. Two-way ANOVA and the post-hoc Tukey test were used for quantitative and qualitative artifact analysis. The Dunnet test was also used for qualitative analysis. The significance level was set at P<.05. RESULTS: There were no significant interactions among the exposure parameters in the quantitative or qualitative analysis. Significant differences were observed among the studied filling materials in all quantitative analyses. In the qualitative analyses, all materials differed from the control group in terms of hypodense and hyperdense lines (P<.05). Fiberglass posts did not differ statistically from the control group in terms of hypodense halos (P>.05). CONCLUSION: Different exposure parameters did not affect the objective or subjective observations of artifacts in CBCT images; however, the filling materials used in endodontic restorations did affect both types of assessments.

Application of a newly developed software program for image quality assessment in cone-beam computed tomography.

PURPOSE: The purpose of this study was to apply a newly developed free software program, at low cost and with minimal time, to evaluate the quality of dental and maxillofacial cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: A polymethyl methacrylate (PMMA) phantom, CQP-IFBA, was scanned in 3 CBCT units with 7 protocols. A macro program was developed, using the free software ImageJ, to automatically evaluate the image quality parameters. The image quality evaluation was based on 8 parameters: uniformity, the signal-to-noise ratio (SNR), noise, the contrast-to-noise ratio (CNR), spatial resolution, the artifact index, geometric accuracy, and low-contrast resolution. RESULTS: The image uniformity and noise depended on the protocol that was applied. Regarding the CNR, high-density structures were more sensitive to the effect of scanning parameters. There were no significant differences between SNR and CNR in centered and peripheral objects. The geometric accuracy assessment showed that all the distance measurements were lower than the real values. Low-contrast resolution was influenced by the scanning parameters, and the 1-mm rod present in the phantom was not depicted in any of the 3 CBCT units. Smaller voxel sizes presented higher spatial resolution. There were no significant differences among the protocols regarding artifact presence. CONCLUSION: This software package provided a fast, low-cost, and feasible method for the evaluation of image quality parameters in CBCT.

Assessment of condyle position, fossa morphology, and disk displacement in symptomatic patients.

OBJECTIVE: The aim of the study was to determine whether there are any associations between the morphology of the glenoid fossa, articular spaces, and disk displacement by evaluating the magnetic resonance imaging (MRI) scans of symptomatic patients. Gender and age were also evaluated for any effect on the parameters. STUDY DESIGN: MRI scans of 199 temporomandibular joints were assessed for the morphology of the glenoid fossa and articular spaces in both sagittal and coronal views. The presence of disk displacement and its type in closed-mouth and open-mouth positions were also assessed. Analysis of variance (ANOVA), Tukey, and Student t tests or Mann-Whitney rank sum tests were used to investigate the associations among these variables. RESULTS: A total of 113 joints (56.8%) were presented with disk displacement. The articular spaces observed in sagittal and coronal views were, overall, significantly larger in males than in females in 3 of the 6 spaces (superior, posterior, and central spaces). Larger superior and medial articular spaces were associated with angled glenoid fossae. Higher mean values of the articular space sizes were associated with normal disk position (P < .001), except for the anterior articular space. When displacement was identified, higher values of the articular space sizes were also associated with disk reduction in the open-mouth position (P < .05). CONCLUSIONS: Condyles in the central position in the coronal view and slightly anteriorly positioned in the sagittal view are less likely to present disk displacement.

Relationship between articular eminence inclination and alterations of the mandibular condyle: a CBCT study.

This study aimed at verifying the correlation among angulation of the articular eminence (AE), shape of the condyle and its degenerative bone diseases (DBDs), according to age and sex, through Cone Beam Computed Tomography (CBCT). Five hundred and twenty-eight temporomandibular joints (TMJ) were evaluated. The condyles were classified as: flat, convex, angled and rounded, and the AE angulation was measured. The DBDs evaluated were osteophytes, flattening, erosion, subcortical cysts and spinal sclerosis. There was no difference in the mean angulations in relation to age group (p>0.05). In age groups of 60-69 years (p=0.003) and 70 years or over (p=0.021), the angulation was higher in males. There was an association between DBD and sex (p=0.047), in that the prevalence was higher in females. Differences in AE angles were not observed in condyles with one or no DBDs (p>0.05). However, the presence of two or more DBDs led to a decrease in the angle (p<0.05). Angled condyles showed higher AE angulations than the flat and convex types (p<0.01). In conclusion, the AE inclination is influenced by DBD and condyle shape; an association of two or more bone diseases in the condyle, or its flat or convex anatomy, results in a decrease in the angulation.

Relationship between articular eminence inclination and alterations of the mandibular condyle: a CBCT study

Abstract This study aimed at verifying the correlation among angulation of the articular eminence (AE), shape of the condyle and its degenerative bone diseases (DBDs), according to age and sex, through Cone Beam Computed Tomography (CBCT). Five hundred and twenty-eight temporomandibular joints (TMJ) were evaluated. The condyles were classified as: flat, convex, angled and rounded, and the AE angulation was measured. The DBDs evaluated were osteophytes, flattening, erosion, subcortical cysts and spinal sclerosis. There was no difference in the mean angulations in relation to age group (p>0.05). In age groups of 60-69 years (p=0.003) and 70 years or over (p=0.021), the angulation was higher in males. There was an association between DBD and sex (p=0.047), in that the prevalence was higher in females. Differences in AE angles were not observed in condyles with one or no DBDs (p>0.05). However, the presence of two or more DBDs led to a decrease in the angle (p<0.05). Angled condyles showed higher AE angulations than the flat and convex types (p<0.01). In conclusion, the AE inclination is influenced by DBD and condyle shape; an association of two or more bone diseases in the condyle, or its flat or convex anatomy, results in a decrease in the angulation.

Instalação de mini-implantes: qual a melhor imagem radiográfica para avaliação do espaço interradicular? / Mini-implants placement: which is the best x-ray imagine for interradicular

O objetivo desse estudo foi comparar a eficácia entre a tomografia computadorizada de feixe cônico (padrão-ouro) e as radiografias periapical, interproximal e panorâmica digitais para avaliação do espaço inter-radicular com vistas à instalação de mini-implantes. Métodos: a amostra foi composta por 40 sítios eleitos nos espaços inter-radiculares na região posterior. Os pontos de inserção para instalação dos mini-implantes foram representados por guta-percha em moldeira de acetato que os pacientes usavam durante as radiografias e a tomografia. Através do programa Adobe Acrobat 9 Pro Extend foram feitas medidas interradiculares no sentido horizontal nos três métodos radiográficos e comparadas com as da tomografia, que foram realizadas pelo Kodak Dental Imaging Software 3D. A comparação utilizou o coeficiente de Lin. Resultados: foi observada diferença estatisticamente significante entre a tomografia computadorizada e as radiografias panorâmicas (27,8% - P > 0,05). Conclusões: a radiografia interproximal foi o método mais preciso; a radiografia panorâmica e a periapical não são recomendadas para verificação do espaço inter-radicular, pois apresentaram alteração da dimensão dessa região no sentido horizontal.(AU)

The objective of this study was to compare the assessment of interradicular space for mini-implants fitting between the cone beam computed tomography (gold standard) and periapical, interproximal and panoramic digital radiographies. Methods: The sample consisted of 40 elected interradicular sites in the posterior area of five patients. These areas were represented by gutta percha points in acetate trays that patients used when radiographies and tomographies were taken. Horizontal measures, between dental roots, in three radiographic methods were obtained by Adobe Acrobat 9 Pro Extend program and compared with the tomography obtained by Kodak Dental Imaging Software 3D. The comparison was done by Lin coefficient correlation. Results: there was not stastistically difference between tomoghaphy and interproximal radiography (8,4% - p < 0,05). Conclusions: the interproximal radiography was the most accurate radiographic method; the panoramic and periapical radiographies are not recommended for interradicular space verification, because they present horizontal dimension alterations in this region. (AU)

Efficacy of a cone beam computed tomography metal artifact reduction algorithm for the detection of peri-implant fenestrations and dehiscences.

OBJECTIVE: To determine whether the use of a metal artifact reduction (MAR) algorithm improves the detection of peri-implant fenestrations and dehiscences on cone beam computed tomography scans. STUDY DESIGN: One hundred titanium fixtures were implanted into bovine ribs after the creation of defects simulating fenestrations and dehiscences. Images were acquired using four different protocols, namely, A2 (MAR on, voxel 0.2 mm), A3 (MAR on, voxel 0.3 mm), B2 (MAR off, voxel 0.2 mm), and B3 (MAR off, voxel 0.3 mm). For all protocols, receiver operating characteristic (ROC) curves were determined. Values for the areas under the ROC curves (Az) were subjected to analysis of variance. RESULTS: Az values were not statistically different among protocols regardless of the defect type (P > .05). CONCLUSIONS: The MAR algorithm tested by us did not improve the diagnosis of peri-implant fenestrations and dehiscences with use of either the 0.2 mm or the 0.3 mm voxel sizes.

Morphometric features of the mandibular condyle and association with disk abnormalities.

OBJECTIVE: The aim of this study was to evaluate the relationship between the morphometric characteristics of the condyle and temporomandibular joint (TMJ) disk displacement. STUDY DESIGN: One hundred and nine individuals who underwent magnetic resonance imaging of the TMJ were evaluated. Linear (D1: condyle width; D2: condyle thickness) and angular (A1: horizontal condylar angle; A2: anterior condylar angle; A3: medial condylar angle) measurements were made. These measurements were associated with articular disk displacement, with and without reduction. RESULTS: There was statistically significant association between limited D1 and D2 and between A1 above and A1 below the mean and displacement of the joint disk. There was statistically significant association between A2 and anterior displacement of the disk. Furthermore, thicker condyles and/or condyles with smaller horizontal angles and/or with smaller medial angles were associated with articular disk reduction. CONCLUSIONS: The morphometric characteristics of the bony components of the TMJ are related to articular disk displacement and with its reduction or nonreduction.

Skin Doses on the Lens for Temporomandibular Joint Exam in Cone Beam Computed Tomography

ABSTRACT The aim of this study was to evaluate the kerma at the surface of the lens in TMJ CBCT and to derive the equivalent dose. An anthropomorphic phantom of the head and neck manufactured by Radiation Support Devices (model RS-230) was used. The dosimetric measurements were obtained by using fourteen thermoluminescent dosimetry (TLD) dosimeters (LiF: Mg, Ti), divided in two pairs (one pair for each eye) and positioned on the surface of the phantom, per scanner evaluated. The tomographic images were acquired in three types of CBCT equipment (CS 9000, Gendex GXCB 500 and i-CAT). Values of equivalent dose obtained were: 5.82 mSv (CS 9000); 5.38 mSv (Gendex GXCB 500) and 7.98 mSv (i-CAT), which varied in accordance with the scanner and the exposure factors used in the image acquisition. The Gendex GXCB 500 used larger FOV and higher kV, resulting in levels close to those obtained on the CS 9000, while larger doses were associated with the i-CAT. The dose values associated with TMJ radiological procedures should be performed with awareness and appropriateness due to sensitivity of the lens.

Avaliação do dimorfismo sexual por meio de medidas lineares entre os processos mastoides e a espinha nasal anterior em crânios secos humanos / Evaluation of the sexual dimorphism by linear measurements between the mastoid process and the anterior nasal spine in human dry skulls

Objetivo ­ Desenvolver um novo método para a estimativa do sexo a partir de medidas entre os processos mastoides e a espinha nasal anterior em crânios secos humanos. Métodos ­ A amostra foi composta por 299 crânios, sendo 181 masculinos e 118 femininos, todos de indivíduos com idades conhecidas. Em cada crânio foram realizadas medidas lineares através de pontos craniométricos selecionados previamente. Foram realizadas as seguintes medidas: N-ENA (distância entre o násio e a espinha nasal anterior); PIMD-ENA (distância entre o polo inferior do processo mastóide direito e espinha nasal anterior) e PIME-ENA (distância entre o polo inferior do processo mastóide esquerdo e espinha nasal anterior). A partir da obtenção das medidas lineares, também foi determinada a uma área triangular, delimitada pela distância da espinha nasal anterior aos polos inferiores dos processos mastóides. Resultados ­ Pode-se observar que todas as distâncias lineares foram maiores no sexo masculino que no feminino e, consequentemente, a área triangular também foi maior. Houveram diferenças estatisticamente significativas entre todas as medidas realizadas de acordo com o dimorfismo sexual, bem como em relação a área triangular (P<0.05). Conclusão ­ O método proposto neste estudo pode ser utilizado para a determinação do dimorfismo sexual, onde os homens possuem medidas lineares maiores que as mulheres.

Objective ­ To develop a new method in order to estimate the sex although measurements between the mastoid processes to the anterior nasal spine in human dry skulls. Methods ­ The sample was composed of 299 skulls, being 181 male and 118 female, all of the individuals with the knowledge age. In each skull was performed linear measurements in selected craniometric points. It was performed the follow measurements: N-ANE (distance between the nasium and the anterior nasal spine); IPRMP-ANE (distance between the inferior polo of the right mastoid process and the anterior nasal spine) and IPLMP-ANE (distance between the inferior polo of the left mastoid process and the anterior nasal spine). Based on the linear measurements, it was determined was well as the triangular area, delimited by the anterior nasal spine and both mastoid processes. Results ­ It was possible to observe that all linear distances were higher in males than in females and, consequently, the triangular area. Statistical significant differences were observed in all measurements according to sex dimorphism, as well as in relation to the triangular area (P<0.05). Conclusion ­ The proposed method in this study could be used in order to determinate the sexual dimorphism, being the measurements in male higher than in females

Evaluation of temporomandibular joint disk displacement and its correlation with pain and osseous abnormalities in symptomatic young patients with magnetic resonance imaging.

OBJECTIVE: To evaluate the occurrence of temporomandibular joint disk displacement and its correlation with pain and osseous abnormalities using magnetic resonance imaging (MRI) in patients under 21 years of age. STUDY DESIGN: MRI images in open- and closed-mouth positions from 102 patients, under 21 years of age (mean age 17 years), were studied retrospectively. Patients were divided into six groups according to the disk-condyle relationship. Chi-square, Marascuilo procedure, and Cochran-Mantel-Haenszel tests were used to evaluate the relationships among pain, abnormalities, and the groups. RESULTS: There was a statistically significant correlation between bilateral disk displacement without reduction and pain (P = .011), and osseous changes (P < .0001). There was no proven link between pain and osseous abnormality (P = .414). CONCLUSION: Young patients are susceptible to all stages of disk displacement. There was a strong correlation only between each variable (osseous abnormalities and pain) and the most severe stage of disk displacement (bilateral disk displacement without reduction).

Cone-beam computed tomography findings of impacted upper canines.

PURPOSE: To describe the features of impacted upper canines and their relationship with adjacent structures through three-dimensional cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: Using the CBCT scans of 79 upper impacted canines, we evaluated the following parameters: gender, unilateral/bilateral occurrence, location, presence and degree of root resorption of adjacent teeth (mild, moderate, or severe), root dilaceration, dental follicle width, and presence of other associated local conditions. RESULTS: Most of the impacted canines were observed in females (56 cases), unilaterally (51 cases), and at a palatine location (53 cases). Root resorption in adjacent teeth and root dilaceration were observed in 55 and 47 impacted canines, respectively. In most of the cases, the width of the dental follicle of the canine was normal; it was abnormally wide in 20 cases. A statistically significant association was observed for all variables, except for root dilaceration (p=0.115) and the side of impaction (p=0.260). CONCLUSION: Root resorption of adjacent teeth was present in most cases of canine impaction, mostly affecting adjacent lateral incisors to a mild degree. A wide dental follicle of impacted canines was not associated with a higher incidence of external root resorption of adjacent teeth.

Influence of the milliamperage settings on cone beam computed tomography imaging for implant planning.

PURPOSE: To evaluate the influence of the milliamperage settings on cone beam computed tomography (CBCT) images for qualitative and quantitative preoperative implant planning. MATERIALS AND METHODS: Eight dry mandibles were scanned under different milliamperage values (2, 4, 6.3, 8, 10, 12, and 15 mA) available for selection on the Kodak 9000 CBCT unit. Cross-sectional slices of incisor, canine, premolar, first molar, and second molar regions were analyzed by three oral radiologists. A subjective image quality evaluation of the height measurements compared with the real measurements obtained in the mandible were performed. After 30 days, 25% of the sample was reevaluated to obtain the reproducibility of the results. RESULTS: The weighted-kappa coefficient and intraclass correlation coefficient for intra- and interobserver agreement varied between moderate and substantial agreement for the image quality evaluation, and excellent agreement was found for the bone measurements. For the image quality evaluation, the Friedman test showed a negative influence of the milliamperage setting only when the lowest values (2 and 4 mA) were used; for the measurements, one-way analysis of variance with the post hoc Tukey test showed that milliamperage settings did not influence their accuracy. However, images obtained with 6.3 mA were closest to the real measurements. CONCLUSION: On the basis of this study of dried skulls using CBCT, it was determined that image quality degradation was not significantly improved when the milliamperage setting was increased above 6.3 mA, whereas a milliamperage level below 6.3 mA resulted in degradation of the image quality. Therefore, significant dose reduction can be achieved with diagnostically satisfactory image quality on CBCT exams for implant planning by reducing the milliamperage setting.

Evaluation of cone-beam computed tomography in the diagnosis of vertical root fractures: the influence of imaging modes and root canal materials.

INTRODUCTION: The purpose of this study was to evaluate the influence of cone-beam computed tomography (CBCT) imaging modes in the diagnosis of vertical root fractures with different intracanal materials. METHODS: The sample consisted of 30 single-rooted teeth divided into 3 groups (n = 10), control and complete and incomplete root fracture. In each tooth, different materials were used (gutta-percha, metal post, and fiber post) as well as no filling material. Each tooth/root was scanned in a 3D Accuitomo 170 CBCT device by using 4 different imaging modes (high-resolution, high-fidelity, high-speed, and standard). In addition, the dose-area product was calculated for each CBCT imaging mode. The images were randomly evaluated by 5 dentomaxillofacial radiologists. RESULTS: Complete root fractures were visualized more easily than incomplete fractures. The presence of metal post and gutta-percha negatively influenced the diagnosis of root fracture. Regarding the CBCT imaging modes, there was no influence for complete root fracture diagnosis. In cases of incomplete root fractures, high-fidelity, high-resolution, and standard had a higher diagnostic accuracy, especially in the fiber post and no filling groups. CONCLUSIONS: The CBCT imaging modes had little influence in the diagnosis of complete and incomplete root fractures, whereas the presence of intracanal material had greater impact on the diagnostic ability, demonstrating that CBCT is not beneficial for the diagnosis of root fractures when metal posts are present.