Impact of Temporomandibular Joint Discectomy on Condyle Morphology: An Animal Study.

PURPOSE: Temporomandibular disorders lead to parafunctional activity that may alter bone remodeling of mandibular components. This animal study aimed to assess the impact of temporomandibular joint discectomy on condylar bone microarchitecture. MATERIALS AND METHODS: A total of 30 one-month-old Wistar rats were assessed and divided into 3 equal groups (2 test groups and 1 control group) of 10. The first test group underwent disc removal, the second test group underwent disc and condylar cartilage removal, and the 10 remaining rats were analyzed as sham-operated controls, following a split-mouth design. The rats were killed humanely 2 months after surgery, and the respective mandibles were scanned with micro-computed tomography for quantitative morphometric analysis. RESULTS: There were significant differences among the 3 groups analyzed (disc removal, disc and condylar cartilage removal, and sham-operated control) for bone volume fraction (ratio of bone volume to total volume, P = .044), structure model index (P < .001), fractal dimension (P = .024), and porosity (P = .023). In addition, operated and contralateral nonoperated sides significantly differed for all variables in at least 1 of the test groups (P < .05) but not in the control group (P > .05). CONCLUSIONS: Within the limitations of this study, our results suggest that discectomy may lead to alterations of the mandibular condylar morphology.

Simple Bone Cyst Mimicking Stafne Bone Defect.

Stafne bone defects (SBDs) are asymptomatic lingual bony defects in mandible, which are usually detected as an incidental finding in plain radiographs. Similarly, simple bone cysts (SBCs) are most frequently found in posterior region of the mandible and also are asymptomatic. However, due to anatomical structures overlap in plain radiographs, there is a possibility of misdiagnosing SBD that often is diagnosed by presumptive diagnosis observed in plain radiograph. This report shows an unusual case that a SBC resembles a SBD.

Comparison of Pixel Values of Maxillary Sinus Grafts and Adjacent Native Bone With Cone-Beam Computed Tomography.

PURPOSE: Pixel values from cone-beam computed tomography (CBCT) are proportional to bone density. This study aimed to correlate and compare pixel values of healed maxillary sinus grafts and adjacent native bone (NB). MATERIAL AND METHODS: This study was conducted on CBCT scan patients referred for maxillary sinus floor augmentation with biphasic calcium phosphate (n = 31). Graft height and width measurements were performed. In addition, mean pixel values were calculated in 3 different regions: NB, sinus graft close to NB (CNB), and sinus graft far from NB (FNB). Micro-CT and histological analyses of bone specimens of a representative case were also performed. RESULTS: Significant correlations were found between CNB and graft height (r = 0.41; P < 0.021); and FNB and graft width (r = 0.519, P < 0.003). In addition, pixel values from both graft groups (CNB and FNB) differed significantly (P < 0.001). Finally, histological sections revealed smaller areas with newly formed bone in the FNB area. CONCLUSIONS: Within the limitations of this study, the present findings suggest that pixel values of sinus grafted areas are directly correlated with the extension of the grafted area.

Diffusion-weighted magnetic resonance imaging of mandibular bone marrow: do apparent diffusion coefficient values of the cervical vertebrae and mandible correlate with age?

OBJECTIVES: The objective of this investigation was to assess the correlation between the mandible and cervical vertebrae bone marrow apparent diffusion coefficient (ADC), obtained by diffusion-weighted magnetic resonance imaging (DWI), with age; to verify the correlation between ADC values from the mandible and the cervical vertebrae; to describe and assess the differences between ADC values obtained from DWI examinations of distinct mandible areas as well as cervical vertebrae. METHODS: Thirty imaging examinations with DWI for that included the mandible and C1, C2, C3, and C4 vertebrae in the same examination were included. ADC values were collected from 7 distinct areas in the mandible and the cervical vertebrae. Differences between ADC values and non-parametric correlations were performed. RESULTS: A total of 270 regions were assessed. No significant difference was found between ADC values of all areas tested. An inverse correlation was found between C2, C3, and C4 vertebrae ADC values and age. The significant correlation of anatomic area ADC values and age were presented as graphics to verify if the linear trend of ADC values and age are in accordance with the literature CONCLUSIONS: The mandible area that most correlates with the cervical vertebrae, using ADC values, is the posterior trabecular area, below the inferior molars. Also, C2, C3, and C4 vertebrae ADC values inversely correlate with age, which demonstrates the bone qualitative changes in bone composition. ADC values may be useful for the qualitative assessment of bone quality to screen patients at osteoporosis risk.

Correlation among alveolar bone assessments provided by CBCT, micro-CT, and 14 T MRI.

OBJECTIVES: The aim of this study was to evaluate bone mineral adipose tissue (BMAT) volume in 21 alveolar bone specimens, as determined by 14 T MRI, and correlate them to the radiodensity values obtained pre-operatively of regions of interest (ROIs) by cone beam computed tomography (CBCT), and to the bone-volume-to-tissue-volume ratio values obtained by micro-CT, the gold-standard for morphometric data collection. METHODS: Partially edentulous patients were submitted to a CBCT scan, and the radiographic bone densities in each ROI were automatically calculated using coDiagnostiX software. Based on the CBCT surgical planning, a CAD/CAM stereolithographic surgical guide was fabricated to retrieve a bone biopsy from the same ROIs scanned preoperatively, and then to orientate the subsequent implant placement. The alveolar bone biopsies were then collected and scanned using the micro-CT and 14 T MRI techniques. Pearson's correlation test was performed to correlate the results obtained using the three different techniques. RESULTS: In the 21 eligible bone specimens (6 females, 15 males), age (mean age 52.9 years), micro-CT, and 14 T MRI variables were found to be normally distributed (p > 0.05). The strongest-and only statistically significant (p < 0.05)-correlation was found between micro-CT and 14 T MRI values (r = 0.943), and the weakest, between 14 T MRI and CBCT values (r = -0.068). CONCLUSIONS: The findings suggest that 14 T MRI can be used to evaluate BMAT as an indirect marker for bone volume, and that CBCT is not a reliable technique to provide accurate bone density values.

Influence of receiver bandwidth on MRI artifacts caused by orthodontic brackets composed of different alloys.

PURPOSE: The aim of this in vitro study was to assess the role of bandwidth on the area of magnetic resonance imaging (MRI) artifacts caused by orthodontic appliances composed of different alloys, using different pulse sequences in 1.5 T and 3.0 T magnetic fields. MATERIALS AND METHODS: Different phantoms containing orthodontic brackets (ceramic, ceramic bracket with a stainless-steel slot, and stainless steel) were immersed in agar gel and imaged in 1.5 T and 3.0 T MRI scanners. Pairs of gradient-echo (GE), spin-echo (SE), and ultrashort echo time (UTE) pulse sequences were used differing in bandwidth only. The area of artifacts from orthodontic devices was automatically estimated from pixel value thresholds within a region of interest (ROI). Mean values for similar pulse sequences differing in bandwidth were compared at 1.5 T and 3.0 T using analysis of variance. RESULTS: The comparison of groups revealed a significant inverse association between bandwidth values and artifact areas of the stainless-steel bracket and the self-ligating ceramic bracket with a stainless-steel slot (P<0.05). The areas of artifacts from the ceramic bracket were the smallest, but were not reduced significantly in pulse sequences with higher bandwidth values (P<0.05). Significant differences were also observed between 1.5 T and 3.0 T MRI using SE and UTE, but not using GE 2-dimensional or 3-dimensional pulse sequences. CONCLUSION: Higher receiver bandwidth might be indicated to prevent artifacts from orthodontic appliances in 1.5 T and 3.0 T MRI using SE and UTE pulse sequences.

Comparison between different cone-beam computed tomography devices in the detection of mechanically simulated peri-implant bone defects.

PURPOSE: This study compared 2 cone-beam computed tomography (CBCT) systems in the detection of mechanically simulated peri-implant buccal bone defects in dry human mandibles. MATERIALS AND METHODS: Twenty-four implants were placed in 7 dry human mandibles. Peri-implant bone defects were created in the buccal plates of 16 implants using spherical burs. All mandibles were scanned using 2 CBCT systems with their commonly used acquisition protocols: i-CAT Gendex CB-500 (Imaging Sciences, Hatfield, PA, USA; field of view [FOV], 8 cm×8 cm; voxel size, 0.125 mm; 120 kVp; 5 mA; 23 s) and Orthopantomograph OP300 (Intrumentarium, Tuusula, Finland; FOV, 6 cm×8 cm; voxel size, 0.085 mm; 90 kVp; 6.3 mA; 13 s). Two oral and maxillofacial radiologists assessed the CBCT images for the presence of a defect and measured the depth of the bone defects. Diagnostic performance was compared in terms of the area under the curve (AUC), accuracy, sensitivity, specificity, and intraclass correlation coefficient. RESULTS: High intraobserver and interobserver agreement was found (P<0.05). The OP300 showed slightly better diagnostic performance and higher detection rates than the CB-500 (AUC, 0.56±0.03), with a mean accuracy of 75.0%, sensitivity of 81.2%, and specificity of 62.5%. Higher contrast was observed with the CB-500, whereas the OP300 formed more artifacts. CONCLUSION: Within the limitations of this study, the present results suggest that the choice of CBCT systems with their respective commonly used acquisition protocols does not significantly affect diagnostic performance in detecting and measuring buccal peri-implant bone loss.

Correlation between magnetic resonance imaging and cone-beam computed tomography for maxillary sinus graft assessment.

PURPOSE: Little is known regarding the accuracy of clinical magnetic resonance imaging (MRI) protocols with acceptable scan times in sinus graft assessment. The aim of this study was to evaluate the correlations between MRI and cone-beam computed tomographic (CBCT) measurements of maxillary sinus grafts using 2 different clinical MRI imaging protocols. MATERIALS AND METHODS: A total of 15 patients who underwent unilateral sinus lift surgery with biphasic calcium phosphate were included in this study. CBCT, T1-weighted MRI, and T2-weighted MRI scans were taken 6 months after sinus lift surgery. Linear measurements of the maximum height and buccolingual width in coronal images, as well as the maximum anteroposterior depth in sagittal images, were performed by 2 trained observers using CBCT and MRI Digital Imaging and Communication in Medicine files. Microcomputed tomography (micro-CT) was also performed to confirm the presence of bone tissue in the grafted area. Correlations between MRI and CBCT measurements were assessed with the Pearson test. RESULTS: Significant correlations between CBCT and MRI were found for sinus graft height (T1-weighted, r=0.711 and P<0.05; T2-weighted, r=0.713 and P<0.05), buccolingual width (T1-weighted, r=0.892 and P<0.05; T2-weighted, r=0.956 and P<0.05), and anteroposterior depth (T1-weighted, r=0.731 and P<0.05; T2-weighted, r=0.873 and P<0.05). The presence of bone tissue in the grafted areas was confirmed via micro-CT. CONCLUSION: Both MRI pulse sequences tested can be used for sinus graft measurements, as strong correlations with CBCT were found. However, correlations between T2-weighted MRI and CBCT were slightly higher than those between T1-weighted MRI and CBCT.

The value of the apparent diffusion coefficient calculated from diffusion-weighted magnetic resonance imaging scans in the differentiation of maxillary sinus inflammatory diseases.

OBJECTIVES: This study examined the value of the apparent diffusion coefficient (ADC) calculated by using diffusion-weighted imaging (DWI) in the differentiation of inflammatory lesions of the maxillary sinus. STUDY DESIGN: Sixty-five maxillary sinus magnetic resonance imaging (MRI) scans with findings suggestive of inflammatory lesions were qualitatively categorized into 4 distinct groups by using T2-weighted images: group 1: presence of mucosal thickening; group 2: presence of sinonasal polyps or mucous retention cysts; group 3: presence of fluid identified by air-fluid levels with a homogeneous signal intensity; and group 4: presence of fluid identified by air-fluid levels with a heterogeneous signal intensity. The ADC of each imaging finding was measured by using a 5-mm area of interest. Statistical differences between the groups were determined by using nonparametric tests with a 5% significance level. RESULTS: Statistically significant differences were observed between group 1 and the other groups. Mucosal thickening was associated with lower ADC values compared with the other inflammatory lesions. CONCLUSIONS: The ADC can be useful in differentiating mucosal thickening from other inflammatory alterations in the maxillary sinuses. Mucosal thickening had more restricted water diffusion compared with the other inflammatory lesions.

Diffusion-Weighted Magnetic Resonance Imaging in Maxillary Sinuses Inflammatory Diseases: Report of Three Cases and Literature Review.

BACKGROUND: Magnetic resonance imaging is considered a preferable imaging examination in the diagnosis of inflammatory maxillary sinus disease and can provide precise sinonasal characterization. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient are complementary magnetic resonance imaging tools that can be applied to the differentiation of sinus diseases. In this report, 3 cases of inflammatory maxillary sinus diseases imaging findings considering diffusion-weighted magnetic resonance imaging features were described. Additionally, a literature review considering the use of diffusion-weighted magnetic resonance imaging in inflammatory lesions is provided. METHODS: The cases reported were: presence of air-fluid levels, mucosal thickening and a mucous retention cyst. Conventional magnetic resonance imaging and apparent diffusion coefficient (ADC) maps, with ADC values were demonstrated. In the literature review, the studies considering inflammatory lesions were detailed, as well as ADC values established by investigators. RESULTS: ADC values for presence of air-fluid levels, mucosal thickening and mucous retention cyst were respectively: 1.99 x 10-3 mm2/s; 1.83 x 10-3 mm2/s; 2.05 x 10-3 mm2/s. CONCLUSIONS: It was observed that apparent diffusion coefficient values from the inflammatory lesions described in this report were different and apparent diffusion coefficient may be useful in the differentiation of these maxillary sinus alterations. Further larger sample investigations considering apparent diffusion coefficient values focusing in inflammatory lesions are recommended. The lack of studies considering the use of diffusion-weighted magnetic resonance imaging on inflammatory diseases diagnostic was the major limitation to the literature review.

Diffusion-weighted magnetic resonance imaging of the paranasal sinuses: A systematic review.

OBJECTIVES: This was a systematic review of studies on the use of diffusion-weighted imaging (DWI) for paranasal sinus diseases. The applications of DWI were analyzed along with the main results, and conclusions were obtained by the investigators. STUDY DESIGN: Databases were searched using the keyword "diffusion" combined with "sinonasal," "paranasal sinus," "maxillary sinus," "frontal sinus," "ethmoid sinus," and "sphenoid sinus," including only articles that were published from 2008 to 2018. Only original English language studies with sinonasal disease samples were selected. RESULTS: Sixteen studies about various sinonasal diseases were included. The main objectives of most of the studies were related to the use of the apparent diffusion coefficient (ADC) in the differentiation of benign lesions and malignant neoplasms. We concluded that the ADC for malignant neoplasms is lower. Histologic features of samples evaluated in the studies were heterogeneous. CONCLUSIONS: The ADC may improve the quality of the diagnostic hypothesis, particularly in differentiating benign and malignant diseases. Furthermore, the differences between certain types of lesions could be determined by using the ADC. However, further studies focusing on inflammatory diseases should be performed. Overall, DWI and the ADC are promising methods that can be incorporated into routine evaluations.

Comparison of the diagnostic performance of panoramic and occlusal radiographs in detecting submandibular sialoliths.

PURPOSE: The aim of this study was to assess and compare the diagnostic performance of panoramic and occlusal radiographs in detecting submandibular sialoliths. MATERIALS AND METHODS: A total of 40 patients (20 cases and 20 controls) were included in this retrospective study. Cases were defined as subjects with a submandibular sialolith confirmed by computed tomography (CT), whereas controls did not have any submandibular calcifications. Three observers with different expertise levels assessed panoramic and occlusal radiographs of all subjects for the presence of sialoliths. Intraobserver and interobserver agreement were assessed using the kappa test. Sensitivity, specificity, accuracy, positive and negative predictive values, and the diagnostic odds ratio of panoramic and occlusal radiographs in screening for submandibular sialoliths were calculated for each observer. RESULTS: The sensitivity and specificity values for occlusal and panoramic radiographs all ranged from 80% to 100%. The lowest values of sensitivity and specificity observed among the observers were 82.6% and 80%, respectively (P=0.001). Intraobserver and interobserver agreement were higher for occlusal radiographs than for panoramic radiographs, although panoramic radiographs demonstrated a higher overall accuracy. CONCLUSION: Both panoramic and occlusal radiographic techniques displayed satisfactory diagnostic performance and should be considered before using a CT scan to detect submandibular sialoliths.

Reliability and Reproducibility of Manual and Automated Volumetric Measurements of Periapical Lesions.

INTRODUCTION: The present study aimed to test the reliability and reproducibility of 2 methods: manual and automated segmentation (using a threshold-based region growing algorithm) for measuring the volume of periapical lesions. METHODS: A total of 43 cone-beam computed tomographic scans (14 men and 29 women, mean age of 54.6 ± 8.5 years) were analyzed by 3 observers. Intraobserver reproducibility and interobserver reliability were assessed using the intraclass correlation coefficient. Parametric correlation between manual and automated volumetric measurements was performed. In addition, the Student t test was also used to compare the mean time required for manual and automated volumetric measurements. RESULTS: Automated segmentation showed slightly higher intraclass correlation coefficient values for all observers. A strong significant correlation was found between manual and automated volumetric measurements performed by the 3 observers. A significant difference in the mean procedure time was also found between both methods (P = .001). CONCLUSIONS: Within the limitations of this study, the present results suggest that automated segmentation with a region growing algorithm is faster and slightly more reliable to calculate the volume of periapical lesions.

Bone mineral density and mandibular osteoporotic alterations in type 2 diabetes / Densidade mineral óssea e alterações osteoporóticas na mandíbula em pacientes diabéticos do tipo 2

Objective: To assess the influence of type 2 diabetes on bone mineral density in a group of type 2 diabetic patients, in comparison with non-diabetic patients. Additionally, to evaluate the correlation between mandibular cortical index and bone mineral density. Material and Methods: 48 patients (24 diabetics and 24 non-diabetics) referred for femur and spine densitometry and panoramic radiograph examination were included in this study. Patients were diagnosed based on densitometric results of the total femur and total spine. All panoramic radiomorphometric measurements were performed by 3 observers. Differences in T and Z-scores between both groups were evaluated with Mann-Whitney test and non-parametric correlations between mandibular cortical index and T/Z-scores were carried out with Spearman's test. Results: Median T and Z-scores for total femur and total spine presented no statistical significant difference between diabetic and nondiabetic patients. In addition, only diabetics total femur and non-diabetics total spine T-scores were significantly correlated with mandibular cortical index. Conclusion: The present results suggest that type 2 diabetic patients have similar Z and T-scores in femur and spine when compared to non-diabetic patients. Mandibular cortical index, assessed on panoramic radiographs is inversely correlated with femur densitometry results in diabetics and spine bone mineral density in nondiabetic patients. (AU)

Objetivo: avaliar a influência do diabetes tipo 2 na densidade mineral óssea em um grupo de pacientes diabéticos do tipo 2, em comparação com pacientes não diabéticos. Adicionalmente, analisar a correlação entre o índice cortical mandibular e a densidade mineral óssea. Material e Métodos: 48 pacientes (24 diabéticos e 24 não diabéticos) que realizaram densitometria óssea de fêmur e coluna vertebral e exame radiográfico panorâmico foram incluídos neste estudo. Os pacientes foram diagnosticados com base nos resultados densitométricos do fêmur total e da coluna total. Por meio das radiografias panorâmicas, 3 observadores avaliaram o índice da cortical mandibular. Diferenças em T e Z scores entre os dois grupos foram avaliadas com o teste de MannWhitney e as correlações não paramétricas entre o índice cortical mandibular e os scores da densitometria foram verificadas por meio do teste de Spearman. Resultados: A mediana dos T e Z-scores para fêmur total e coluna total não apresentaram diferença estatisticamente significante entre diabéticos e não-diabéticos. Além disso, houve correlação significativa com o índice da cortical mandibular somente os T-scores de fêmur total do grupo de pacientes diabéticos e de coluna total dos paciente não-diabéticos. Conclusão: Os resultados deste estudo sugerem que pacientes diabéticos tipo 2 tem densidade mineral óssea aferida por meio de densitometria óssea do fêmur e coluna total semelhantes aos não-diabéticos. O índice cortical mandibular, avaliado em radiografias panorâmicas, foi inversamente correlacionado com os resultados da densitometria do fêmur em pacientes diabéticos e da densitometria de coluna total de pacientes não diabéticos. (AU)

Influência da largura de banda na dimensão de artefatos provenientes de fios e bráquetes ortodônticos nas sequencias de pulso SE, GRE2D, GRE3D e UTE / Influence of the bandwidth on the dimension of artifacts from orthodontic wires and brackets in the SE, GRE2D, GRE3D and UTE pulse sequences

A ressonância magnética é uma importante modalidade de imagem que não utiliza radiação ionizante, entretanto, como outros exames de diagnóstico, está sujeita a artefatos que podem comprometer a interpretação das imagens. Artefatos de susceptibilidade magnética ocorrem em materiais que respondem à aplicação de um campo magnético, aumentando ou diminuindo sua intensidade localmente. Diferentes materiais odontológicos, como os aparelhos ortodônticos, podem produzir artefatos de susceptibilidade magnética. O objetivo do presente trabalho foi estudar a influência da largura de banda (BW) na dimensão de artefatos provenientes de fios e braquetes ortodônticos. Foram avaliados três tipos de braquetes e dois fios ortodônticos, os quais foram escaneados em RM de 1,5 e 3,0 nas sequências de pulso SE, GRE2D, GRE3D e UTE. As sequências GRE a BW não promoveram redução de artefatos de susceptibilidade. Entretanto, houve acentuada redução de artefatos nas sequências SE e UTE com aumento de largura de banda em braquetes ortodônticos total ou parcialmente metálicos. Em relação aos fios ortodônticos, independentemente da sequência de pulso ou da largura de banda, a extensão dos artefatos impossibilitou a mensuração.

Estudo por meio de microtomografia da qualidade, morfologia óssea, volume da cabeça da mandíbula e volume da fossa articular em ratos (Rattus norvegicus, albinos, Wistar) submetidos a remoção do disco articular e cartilagem articular / Evaluation of Bone quality, morphology and volume of the condyle and volume of articular fossa from Wistar rats after remotion of articular disc and cartilage

Diante da escassez de estudos que correlacionem a remoção do disco ou da cartilagem articular do côndilo, sobretudo, na análise de parâmetros morfométricos, o presente estudo objetivou analisar, por meio de microtomografia, alterações da estrutura e qualidade óssea em ratos (Rattus norvegicus, albinos, Wistar). Os espécimes foram divididos em três grupos experimentais e a cirurgia ocorreu, em todos os grupos, do lado direito. No grupo experimental (RDC), deu-se a remoção do disco articular e remoção da cartilagem articular do lado direito; no grupo experimental (RD), somente remoção do disco articular do lado direito; no grupo experimental (SHAM), apenas acesso cirúrgico e posterior sutura sem danos ao disco articular ou cartilagem. Os côndilos foram analisados por microtomografia e executou-se comparação entre os lados de cada grupo e entre os grupos do lado direito e esquerdo. Os parâmetros morfométricos apontaram para um declínio da estrutura e qualidade óssea, sucessivamente, em ordem crescente, no lado operado dos grupos SHAM, RD e RDC.

Considering that only few studies on the correlation between temporomandibular joint (TMJ) disk removal and conditions of the cartilage of the condyle, especially in the analysis of morphometric parameters, this study aimed to analyze changes in the bone structure and quality in rats (Rattus norvegicus, albino Wistar) with micro-computed tomography. The specimens were divided into three groups that underwent surgery in the right TMJ. In the first experimental group, surgical procedures included both disk and joint cartilage removal (DCR). In the second experimental group, only the disk was removed during surgeries (DR), whereas in the control group (SHAM) only surgical access and subsequent suture without damaging the disc or joint cartilage was performed. The condyles were analyzed by micro-computed tomography and inter-group and intra-group side (left and right) comparisons were carried out. The morphometric parameters indicated a decline in bone structure and quality successively in the groups in ascending order of TMJ surgical damage (control group, SHAM, and the two experimental groups, DR and DCR).