Osteoarthritic Bony Alterations of Temporomandibular Joint and Relation to Low Bone Mineral Density in Postmenopausal Edentulous Females.

This study aimed to evaluate the relationship between osteoarthritic bony alterations in the temporomandibular joint (TMJ) and general bone mineral density (BMD) in postmenopausal edentulous females. Cone beam computed tomography (CBCT) scans for both TMJs were acquired for 80 clinically asymptomatic patients (mean age 72 ± 8.8 y). Both lumbar spine and femoral neck measurements of BMD were performed using dual-energy X-ray absorptiometry (DXA). The most frequently observed bony alterations were flattening of the articular surface (47.5%), sclerosis (41.5%), subcortical cysts (10%), and erosions (5%). Osteophytes were not observed. No statistical differences were observed between those who had or did not have radiological signs of bony alterations according to age or DXA scores. The prevalence of radiological findings of degenerative TMJ bony alterations in clinically asymptomatic postmenopausal females did not confirm a connection with a generally low BMD.

Comparative Analysis of Examination Methods for Periapical Lesion Diagnostics: Assessing Cone-Beam Computer Tomography, Ultrasound, and Periapical Radiography.

INTRODUCTION: Periapical lesions of teeth are typically evaluated using periapical X-rays (PA) or cone-beam computer tomography (CBCT); however, ultrasound imaging (US) can also be used to detect bone defects. A comparative analysis is necessary to establish the diagnostic accuracy of US for the detection of periapical lesions in comparison with PA and CBCT. OBJECTIVES: This study aimed to evaluate and compare the measurement precision of US against PA and CBCT in detecting periapical lesions. METHODS: This study included 43 maxillary and mandibular teeth with periapical lesions. All teeth were examined clinically, radiographically, and ultrasonographically. Observers evaluated and measured the periapical lesions on CBCT, PA, and US images. RESULTS: The comparison of lesion size showed that it differs significantly between the different methods of examination. A statistically significant difference was found between CBCT and US (mean difference = 0.99 mm, 95% CI [0.43-1.55]), as well as between CBCT and PA (mean difference = 0.61 mm, 95% CI [0.17-1.05]). No difference was found between the US and PA methods (p = 0.193). CONCLUSION: US cannot replace PA radiography in detecting pathologies but it can accurately measure and characterize periapical lesions with minimal radiation exposure. CBCT is the most precise and radiation-intensive method so it should only be used for complex cases.

Modular Neural Networks for Osteoporosis Detection in Mandibular Cone-Beam Computed Tomography Scans.

In this technical note, we examine the capabilities of deep convolutional neural networks (DCNNs) for diagnosing osteoporosis through cone-beam computed tomography (CBCT) scans of the mandible. The evaluation was conducted using 188 patients' mandibular CBCT images utilizing DCNN models built on the ResNet-101 framework. We adopted a segmented three-phase method to assess osteoporosis. Stage 1 focused on mandibular bone slice identification, Stage 2 pinpointed the coordinates for mandibular bone cross-sectional views, and Stage 3 computed the mandibular bone's thickness, highlighting osteoporotic variances. The procedure, built using ResNet-101 networks, showcased efficacy in osteoporosis detection using CBCT scans: Stage 1 achieved a remarkable 98.85% training accuracy, Stage 2 minimized L1 loss to a mere 1.02 pixels, and the last stage's bone thickness computation algorithm reported a mean squared error of 0.8377. These findings underline the significant potential of AI in osteoporosis identification and its promise for enhanced medical care. The compartmentalized method endorses a sturdier DCNN training and heightened model transparency. Moreover, the outcomes illustrate the efficacy of a modular transfer learning method for osteoporosis detection, even when relying on limited mandibular CBCT datasets. The methodology given is accompanied by the source code available on GitLab.

Patient-specific virtual simulation in the clinical training for prosthetic dentistry.

INTRODUCTION: Dental education always involves live patient treatment, and clinical training for each patient is different for students. Using an intraoral scanner and Simodont Dental Trainer, we can provide students with an opportunity to train on actual patient cases in a virtual environment before real preparation. This study aimed to develop, implement and test patient-specific virtual simulation training in prosthetic dentistry curriculum. MATERIALS AND METHODS: Before the actual preparation, the students' patients were scanned using 3Shape intraoral scanner. Thereafter, the .stl file was uploaded to Simodont Dental Trainer (Nissin dental products) where all the scanned teeth were prepared virtually. The 'prepared' .stl file was downloaded and submitted to the teacher. Instruction manuals for virtual simulation patient-specific tasks were provided. The students were asked to voluntarily complete the survey, at the end of the course. RESULTS: Forty-two 4th year students from the Faculty of Dentistry performed a patient-specific virtual simulation training task and completed a survey. The created training materials served as guidelines for students to perform all the steps on their own without teacher assistance, except in the final step, where the teacher evaluated the digital preparation. Students appreciated the amount of information provided regarding the technologies used and patient-specific tasks. Students admitted that the patient-specific task was more interesting than standard tasks. However, they were not satisfied with the technical performance of Simodont Dental Trainer or the reflection of reality. CONCLUSION: Patient-specific virtual simulation can be accepted by students for training before actual teeth preparation in the clinic. However, technical improvements are required in this regard.

The Effect of General Bone Mineral Density on the Quantity and Quality of the Edentulous Mandible: A Cross-Sectional Clinical Study.

BACKGROUND: Osteoporosis is a disease which is characterized by a decrease in general bone mineral density (BMD), resulting in decreased bone strength and an increased risk of bone fractures. The effect of reduced BMD on the jawbones is still not fully understood. The purpose of the study was to evaluate the impact of BMD on the quality and quantity of the edentulous mandible. METHODS: The present study included 127 edentulous postmenopausal women who underwent cone beam computed tomography (CBCT) examinations. BMD measurements of the lumbar spine and femoral necks were performed by dual-energy X-ray absorptiometry. In the cross-sectional CBCT images, three different areas of the mandible (lateral incisor, first premolar, and first molar) were selected. The complete mandibular, trabecular, and cortical bone volumes were measured. All measurements were performed on the total mandibular area, and the basal and alveolar parts of the mandible. RESULTS: The volume of the cortical bone was reduced for females with reduced BMD in the lateral incisor and first premolar regions, both in the total mandibular area and in the basal part of the mandible. The trabecular bone volume statistically significantly increased when the BMD decreased in the complete mandibular area and the basal part of the mandible (linear regression). The total bone volume significantly decreased with a decrease in BMD in the basal part of the mandible. CONCLUSIONS: Reduced BMD has a negative effect on the quantity and quality of bone in the basal part of the edentulous mandible.

Gray values of the cervical vertebrae detected by cone beam computed tomography for the identification of osteoporosis and osteopenia in postmenopausal women.

OBJECTIVES: This study aimed to determine whether the gray values (GVs) of the second and third cervical vertebrae in cone beam computed tomography (CBCT) are affected by general bone mineral density (BMD) in postmenopausal women and to evaluate whether CBCT can be used for predicting the risk of osteoporosis. STUDY DESIGN: The present cross-sectional study included 127 edentulous postmenopausal women (average age, 70.4 ± 8.9 years) who underwent CBCT examinations. BMD measurements of the lumbar spine and both femoral necks were performed by dual-energy x-ray absorptiometry. The CBCT images were analyzed with OnDemand3D Dental software. GVs of the axial and sagittal sections of the cervical second and third vertebral bodies were obtained. RESULTS: The GVs of the second and third cervical vertebrae decreased significantly with decreasing BMD. The axial GV of the second cervical vertebra showed the highest sensitivity (80.6%), highest negative predictive value (89.0%), lowest negative likelihood ratio (0.39), and highest area under the curve value (0.68) to predict osteoporosis. CONCLUSIONS: Women with reduced BMD have lower GVs for the second and third cervical vertebrae. Changes in the GV of the second vertebra can potentially be used to determine the risk of osteoporosis in postmenopausal women.

A population based study of multiple myeloma patients with medication-related osteonecrosis of the jaw.

OBJECTIVE: Medication-related osteonecrosis of the jaw (MRONJ) is a rare complication of antiresorptive or antiangiogenetic therapy that manifests as an exposed bone with clinical signs of infection, persisting for more than 8 weeks, without history of radiation therapy or metastases to the jaws. The aim of the study was to describe the incidence, risk factors, staging process and clinical course of MRONJ in patients with multiple myeloma (MM). MATERIALS AND METHODS: We retrospectively analyzed all (126) newly diagnosed MM patients at Riga East Clinical University Hospital (Riga. Latvia) from June 2014 to June 2017. RESULTS: Among 88 MM patients treated with bisphosphonates (BP), 6 (6.8%) patients developed MRONJ. All six patients received intravenous nitrogen-containing BPs. The average time until MRONJ manifestation was under two years. For our patients the severity of MRONJ was stage I in two, stage II in three, and stage III in one patient. Five patients had MRONJ of mandibula and one of maxilla. All patients with MRONJ had undergone a dental extraction or a trauma before the development of MRONJ. CONCLUSION: We found that MRONJ correlated with the patient's age. The average time until MRONJ manifestation in reserach group is 2 years. One of triggerring MRONJ factors are tooth extraction or trauma.

Bone mineral density and mandibular residual ridge resorption.

PURPOSE: This prospective, cross-sectional study evaluated the relationship between bone mineral density (BMD) and the width and height parameters of the mandibular residual ridge. MATERIALS AND METHODS: BMD was determined in the lumbar spine and femoral necks by dual energy x-ray absorptiometry (DXA) in 45 edentulous, postmenopausal women (mean age, 72.08 ± 8.53 years) who had used conventional complete dentures for at least 3 years. Measurements of the mandibular residual ridge were performed using cone beam computed tomography (CBCT). Height and width measurements were performed in the midline and adjacent to the mental foramina. Data were analyzed with descriptive and analytic statistics. The relationship between BMD and mandibular height and width measurements was assessed using analysis of variance as well as linear and multivariate regression analyses. Eight patients were excluded from the study because they did not complete both of the required imaging analyses (DXA and/or CBCT). RESULTS: There was no statistically significant relationship between BMD and mandibular bone height measurements in the midline and both regions of the mental foramina, and no statistically significant relationship existed between BMD and mandibular bone width measurements in the midline and both of the mental foramina regions. CONCLUSIONS: Postmenopausal women with reduced general BMD do not appear to have a reduction in the size of the mandibular residual ridge.

Vitamin D status and its seasonal variations and association with parathyroid hormone concentration in healthy women in Riga.

UNLABELLED: The aim of the study was to describe the vitamin D status and its seasonal variations in women living in Riga, Latvia, to examine an association between the concentrations of plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH), and to determine the threshold for plasma 25(OH)D above which there is no further suppression of PTH. MATERIAL AND METHODS: The data of 189 healthy Caucasian women were analyzed. The serum levels of 25(OH)D, PTH, and phosphorus were measured twice a year. All the participants were divided into 3 groups according to vitamin D supplementation and the reproductive status. RESULTS: The overall mean level of 25(OH)D was 32.8 ng/mL with significantly lower levels being in winter when compared with those in summer (28.2 ng/mL vs. 37.5 ng/mL, respectively; P<0.05). PTH was negatively associated with 25(OH)D. A threshold level of plasma 25(OH)D above which no further suppression of PTH occurred was found to be 38 ng/mL. Postmenopausal women not taking vitamin D supplements and without exposure to sunlight had 25(OH)D deficiency in winter and summer (92% and 88%, respectively). The most significant seasonal fluctuations were seen in the women of the reproductive age not taking vitamin D supplements and without exposure to sunlight, of which 47% had 25(OH)D deficiency in summer and 69% in winter. CONCLUSIONS: An optimal concentration of 25(OH)D was found to be 38 ng/mL. According to this definition, 70.4% of all the healthy women were classified as vitamin D deficient in winter and 59.8% in summer. The highest proportion of vitamin D deficient individuals was found in the group representing the postmenopausal women not taking vitamin D supplements.

Postmenopausal osteoporosis and tooth loss.

OBJECTIVE: The aim of this study was to determine relation between tooth loss and general body bone mineral density in postmenopausal female who were seeking for prosthetic treatment. MATERIAL AND METHODS: There were included 79 women in this study (age from 49-81 years, mean age 62.9 years) with partial tooth loss. For all patients bone mineral density measurements for lumbar spine and both femoral necks by dual energy X-ray absorptiometry (Lunar DEXA DPX-NT, GE Medical Systems) were performed. Based on DEXA results patients were divided into 3 groups: normal bone density (T-score ≥-1.0), osteopenia (T-score from -1.0 till -2.5) and osteoporosis (T-score ≤-2.5). Dental investigation was performed to detect existing teeth. ANOVA analysis of variance was used to determine relationship between different variables by group. To test correlation between different values Pearson correlation was used. RESULTS: The number of teeth in different bone mineral density groups is almost similar. There are no statistically significant differences between groups according the number of the all teeth present and according the number of teeth in maxilla and mandible. There is no significant correlation between the number of the teeth and DEXA readings, except there is weak correlation between the number of maxillary posterior teeth and bone mineral density in femoral neck. CONCLUSION: There is no correlation between number of the teeth and general bone mineral density.

The influence of bone mineral density and body mass index on resorption of edentulous jaws.

OBJECTIVE: The aim of this study is to determine the relation of osteoporosis and body mass index to edentulous jaw bone resorption. MATERIAL AND METHODS: Study included 48 postmenopausal totally edentulous female patients, aged 50 to 84 years (average age 69.73), with period of at least 2 years after last tooth extraction. Bone mineral density was determined in the femoral neck and the lumbar area L2-L4 by dual energy x-ray absorptiometry (DEXA) using Lunar DEXA DPX-NT, GE Medical Systems hardware. Body mass index was calculated (BMI (kg/m(2))) using data from DEXA results. Lateral cephalogram (Pantomograph Trophycan C), and radiological measurement in the symphysis of the mandible was performed for each patient. Degree of the edentulous residual ridge resorption was determined clinically on diagnostic casts of anatomic impressions by classification of Kalk. RESULTS: There is no statistically significant difference between groups, comparing mandibular bone height changes (p=0.054) and various degrees of residual ridge resorption in maxilla (p=0.743) and mandible (p=0.752) with different bone mineral contents. There is a statistically significant correlation between radiological mandibular measurement and body mass index (p=0.004). Statistically significant difference is also observed between various degrees of residual ridge resorption in maxilla (p=0.049) and mandible (p=0.027) and body mass index. CONCLUSIONS: Resorption of edentulous jaw bone does not increase when bone mineral density decreases. More severe manifestation of edentulous jaw bone resorption is observed in patients with diminished body mass index.

Jaw tracking devices--historical review of methods development. Part I.

Chewing or mastication is one of the main functions of the stomatognathic system. The use of devices for quantitatively measuring mandibular motion has recently become more common in scientific and clinical use. Often, the goal has been to provide an objective basis for diagnosing musculoskeletal disorders of the jaws, to monitor the progress of active treatment methods or to evaluate prosthodontic treatment functional results. To better understand differences between various systems to record mandibular motion a review of recording methods presented over the years was made. To give fundamental description for development of existing methods review was divided in three parts. Part I includes analyses of methods using mechanical devices, photographic methods and roentgenographic methods, describing not only technologies by themselves, but also analyzing essential limitations, possible direction of the functional improvement and, specially, their scientific and clinical significance.

The masticatory system--an overview.

Masticatory muscle physiology has been evaluated mostly from electromyographic recordings. However, electromyography coupled with jaw-tracking devices has provided much more information of the correlation between jaw movements and muscle activity. Knowledge of how the mandible moves during mastication has greatly influenced procedures in clinical dentistry. The aim of this overview is to give basic description of the classical studies of the physiology, function and neural control principles of the mastication. Mastication is the action of breaking down of food, preparatory to deglutition. This breaking-down action is highly organized complex of neuromuscular and digestive activities. The duration and forces developed in the power stroke vary within and between individuals and for the type of the food being chewed. It has been suggested that the observation of masticatory movements may be of diagnostic value for assessing disorders of the stomatognathic system, but there is not clear evidence to show significant differences. The action of masticatory muscles during chewing varies between subjects in amplitude, onset timing, and duration of the chewing cycle. Since tooth guidance has an enormous influence on muscle activity during chewing and swallowing, it is advisable to make restorations compatible with the functional movement patterns of the patient rather than expect the patterns of the mastication to adapt to the new made restorations.

Jaw tracking devices--historical review of methods development. Part II.

Chewing or mastication is one of the main functions of the stomatognathic system. The use of devices for quantitatively measuring mandibular motion has recently become more common in scientific and clinical use. Often, the goal has been to provide an objective basis for diagnosing musculoskeletal disorders of the jaws, to monitor the progress of active treatment methods or to evaluate prosthodontic treatment functional results. To better understand differences between various systems to record mandibular motion a review of recording methods presented over the years was made. To give fundamental description for development of existing methods review was divided in three parts. Part II includes analyses of electronic and telemetric methods, magnetometry and opto-electronic methods, describing not only technologies by themselves, but also analyzing essential limitations, possible direction of the functional improvement and, specially, their scientific and clinical significance.