Comparison of mandibular bone mineral density in osteoporotic, osteopenic and normal elderly edentulous subjects measured by the dual-energy X-ray absorptiometry technique

Occlusal force orchestrates alveolar bone homeostasis via Piezo1 in female mice

Healthy alveolar bone is the cornerstone of oral function and oral treatment. Alveolar bone is highly dynamic during the entire lifespan and is affected by both systemic and local factors. Importantly, alveolar bone is subjected to unique occlusal force in daily life, and mechanical force is a powerful trigger of bone remodeling, but the effect of occlusal force in maintaining alveolar bone mass remains ambiguous. In this study, the Piezo1 channel is identified as an occlusal force sensor. Activation of Piezo1 rescues alveolar bone loss caused by a loss of occlusal force. Moreover, we identify Piezo1 as the mediator of occlusal force in osteoblasts, maintaining alveolar bone homeostasis by directly promoting osteogenesis and by sequentially regulating catabolic metabolism through Fas ligand (FasL)-induced osteoclastic apoptosis. Interestingly, Piezo1 activation also exhibits remarkable efficacy in the treatment of alveolar bone osteoporosis caused by estrogen deficiency, which is highly prevalent among middle-aged and elderly women. Promisingly, Piezo1 may serve not only as a treatment target for occlusal force loss-induced alveolar bone loss but also as a potential target for metabolic bone loss, especially in older patients.

Load transfer across a mandible during a mastication cycle: The effects of odontogenic tumour

The extent to which load transfer in a diseased mandible with odontogenic tumour might influence the potential risk of pathological fracture has scarcely been investigated. The study sought to investigate the quantitative deviations in load transfer across healthy and cancer-affected (diseased) mandibles having odontogenic tumours. The effect of size of the tumours (small: 9 mm diameter, large: 19 mm diameter), and variation in bone mechanical (elastic) properties of the mandible on load transfer in cancer-affected mandibles during a mastication cycle have been investigated. Based on patient-specific computed tomography-scan datasets, detailed three-dimensional finite element models of healthy and diseased mandibles were developed. High stresses of 25-30 MPa and strains ∼700 µε were observed in the healthy mandible during the right molar bite. However, marginal deviations were observed in principal stress distributions in the diseased mandibles with small- and large-sized tumours, as compared to the healthy mandible. Maximum principal strains of ∼1474 µε were found in the body region adjacent to the symphysis region for small-sized tumour. Whereas for large-sized tumour, maximum strains of ∼2700 µε were observed in the right buccal regions. Reduction in Young's modulus due to different stages of odontogenic tumours had a localised effect on the principal stress distributions, but triggered an abrupt increase in the principal tensile strains. It appears that there is a potential risk of pathological fracture for large-sized odontogenic tumour, owing to high tensile stresses and strains.

Mandibular bone mineral density in patients with Behçet's disease

OBJECTIVES

Behçet's disease (BD) is a chronic, recurring vasculitis of unknown etiology. Patients with BD may use a lot of medications associated with the clinical symptoms. Drugs that are used in the treatment of BD may cause bone loss. The aims of the current study were to compare the bone mineral density (BMD) values between BD and healthy volunteers and describe the effect of disease duration on mandibular BMD.

MATERIALS AND METHODS

The study comprised 30 healthy volunteers (15 males and 15 females, mean age 35.50±6.80 years) and 45 patients with BD (24 males and 21 females, mean age 38.93±8.93 years). The BD group was subdivided according to disease duration (0-5, 6-10, and >10 years). The BMD value of the mandibular body was determined by the dual energy X-ray absorptiometry technique.

RESULTS

The mean mandibular body BMD values were 1.294±0.21 g/cm(2) in the control group and 1.216±0.22 g/cm(2) in the BD patients, although there was no statistically significant difference. The BMD was observed to decrease with increased disease duration but not to a statistically significant degree.

CONCLUSION

The results of this study showed that although the BMD value decreased as the duration of the disease increased, no statistically significant difference was found between the BD patients and the healthy control group.

Osteoporosis prediction from the mandible using cone-beam computed tomography

PURPOSE

This study aimed to evaluate the use of dental cone-beam computed tomography (CBCT) in the diagnosis of osteoporosis among menopausal and postmenopausal women by using only a CBCT viewer program.

MATERIALS AND METHODS

Thirty-eight menopausal and postmenopausal women who underwent dual-energy X-ray absorptiometry (DXA) examination for hip and lumbar vertebrae were scanned using CBCT (field of view: 13 cm×15 cm; voxel size: 0.25 mm). Slices from the body of the mandible as well as the ramus were selected and some CBCT-derived variables, such as radiographic density (RD) as gray values, were calculated as gray values. Pearson's correlation, one-way analysis of variance (ANOVA), and accuracy (sensitivity and specificity) evaluation based on linear and logistic regression were performed to choose the variable that best correlated with the lumbar and femoral neck T-scores.

RESULTS

RD of the whole bone area of the mandible was the variable that best correlated with and predicted both the femoral neck and the lumbar vertebrae T-scores; further, Pearson's correlation coefficients were 0.5/0.6 (p value=0.037/0.009). The sensitivity, specificity, and accuracy based on the logistic regression were 50%, 88.9%, and 78.4%, respectively, for the femoral neck, and 46.2%, 91.3%, and 75%, respectively, for the lumbar vertebrae.

CONCLUSION

Lumbar vertebrae and femoral neck osteoporosis can be predicted with high accuracy from the RD value of the body of the mandible by using a CBCT viewer program.

Radiodensitometric and DXA analyses for the measurement of bone mineral density after systemic alendronate therapy

Precise techniques for the measurement of maxillary bone mineral density (BMD) are useful for the early diagnosis of systemic diseases. The aim of this study was to compare in vivo the efficacy of dual-energy x-ray absorptiometry (DXA) and radiographic densitometry for the measurement of BMD after systemic administration of sodium alendronate. Wistar rats were randomly allocated to a control group (n = 5), which received distilled water, and a sodium alendronate group (n = 8), which received two doses of chemically pure sodium alendronate (1 mg/kg) per week. After 8 weeks, the animals were euthanized, the tibias were removed, and the BMD of the proximal tibial metaphysis was analyzed radiographically and by DXA. The data were subjected to statistical analysis by the Kruskal-Wallis test at a significance level of 5%. Both of the techniques revealed that the alendronate-treated group had a significantly higher BMD (p < 0.05) than the control group after 8 weeks of treatment. Comparing the groups with and without alendronate therapy revealed increases of 14.9% and 29.6% in BMD, as detected radiographically and by DXA, respectively. In conclusion, both of the methods were able to detect an increase in BMD of the proximal tibial metaphysis after alendronate therapy.

Comparison of mandibular bone mineral densities in dentate and edentulous patients

PURPOSE

In contemporary implant dentistry, bone mineral density (BMD) of the jaws is a patient-associated prognostic factor. The aim of this study was to compare the mandibular body BMD of dentate and edentulous patients using the dual-energy X-ray absorptiometry (DXA) technique.

MATERIALS AND METHODS

A total of 39 patients, 20 dentate and 19 edentulous, were included in this cross-sectional study. Mandibular body BMD was measured using the DXA technique. The variables were normally distributed; thus, the independent samples t-test was used for the determination of statistical significance between the dentate and edentulous groups (age, body mass index [BMI], DXA). Chi-square test was performed for identification of the gender differences between the groups. The Pearson correlation analysis was used to analyze the relationship between age, BMI, and mandibular body BMD. Note that p < 0.01 was accepted as the significance level.

RESULTS

There was no statistically significant difference between the dentate and edentulous groups in matching variables (age, BMI, and gender) (p > 0.01). There was a statistically significant difference regarding the mandibular body BMD in the dentate and edentulous group (p < 0.01) controlling for age, gender, and BMI. The edentulous group patients had higher mandibular body BMD values (1.27 ± 0.31 g/cm(2)) than those in the dentate group (0.94 ± 0.22 g/cm(2)).

CONCLUSION

Comparison of the mandibular body BMD revealed that dentate patients had less dense bone than the edentulous patients. Further investigations are needed to determine the BMD of the jaws in different regions and for different systemic conditions.