Study of mandible bone mineral density of Chinese adults by dual-energy X-ray absorptiometry

Measurements of volumetric bone mineral density in the mandible do not predict spinal osteoporosis

OBJECTIVE

The objective of this study was to determine whether the trabecular volumetric Bone Mineral Density (vBMD) of the middle, body and angle of the mandible correlates with vBMD of the cervical and lumbar vertebrae in a Chinese population.

METHODS AND MATERIALS

661 subjects (270 males, 391 females), ranging from 20 to 59 years of age, were recruited for vBMD measurements by quantitative CT (QCT). Basic information (age, height and weight), vBMD of the mandible (middle, body and angle sites), and vBMD of the cervical and lumbar vertebrae were recorded. Spearman's rank correlation test was used to investigate the association of mandibular with vertebral vBMD.

RESULTS

The study cohort comprised 661 subjects: 270 (41%) males, 391 (59%) females. Median age in males was 40 (range, 21-59) years. Median age in females was 41 (range, 20-59) years. Values of the Spearman correlation coefficient between mandibular and vertebral vBMD ranged from R = 0.048 to 0.141. In males, the three correlation coefficients between mandibular and cervical vBMD (middle: R = 0.138; body: R = 0.126; angle: R = 0.122) were all statistically significant (p < 0.05). In females, the correlation between the middle mandibular site and cervical site was statistically significant (R = 0.141, p < 0.01). None of the other correlations examined were statistically significant.

CONCLUSION

In this study population, mandibular vBMD was at best weakly correlated with cervical and lumbar vertebral vBMD, indicating that mandibular vBMD should be measured independently for the assessment of mandibular bone status.

Correlation between mandibular bone density and skeletal bone density in a Catalonian postmenopausal population

OBJECTIVES

The aim of this study was to determine if the mandible (MD) experiences reductions in bone mineral density (BMD) similar to the lumbar spine (LS) and femoral neck (FN) in a postmenopausal population.

STUDY DESIGN

A total of 137 postmenopausal women underwent 3 types of densitometric examinations: LS, FN, and MD as measured in 3 regions (MD-R1, MD-R2, and MD-R3), as well as the entire mandible (MD-Net) using a dual photon bone X-ray densitometer. Densitometry of the LS and FN were performed according to the protocol of the International Society for Clinical Densitometry. Mandibular densitometry was performed using a modification of a previous technique, placing the patient in the left lateral decubitus position, with the head supported by a 13-cm-thick cushion above the temporomandibular joint.

RESULTS

Significant correlations were found between densitometry results for the LS and the MD, with P values of .021 at MD-R1 (ramus); .001 at MD-R2 (body); .050 at MD-R3 (symphysis), and .001 at MD-Net (total mandibular density). No correlation was found between mandibular and FN densitometry (P > .05).

CONCLUSIONS

According to the results, for this population, it can be affirmed that the MD responds to osteoporosis in ways similar to the LS.

Interrelationships between tooth properties and biochemical bone turnover markers investigated on six-month-old pig model

The aim of the study was to determine interrelationships between bone tissue metabolism indices and morphological, biomechanical and densitometric properties of hard dental tissues. First primary maxillary incisor from 6-month-old pigs (N=27) was evaluated in terms of weight and length. Mean volumetric tooth mineral density, total tooth volume, enamel total volume, enamel volumetric mineral density, dentine total volume and dentine volumetric mineral density were estimated with the use of quantitative computed tomography and micro computed tomography techniques. Tooth mineral density and tooth mineral content were evaluated with the use of dual-energy X-ray absorptiometry. Microhardness of enamel was measured using Vicker's test. Evaluations of total calcium, ionized calcium, magnesium, phosphorus, alkaline phosphatase, bone alkaline phosphatase, osteocalcin, C-terminal telopeptide of type-I collagen (CTX), insulin-like growth factor-1, growth hormone and parathyroid hormone were performed in plasma and serum samples. Pearson's correlation coefficients were determined between all the investigated variables, and P<0.05 was considered as statistically significant. The obtained results have shown mainly mutual dependences between biochemical indicators of bone metabolism. Evaluation of CTX concentration in serum of pigs has shown the highest predictive value in relation to morphological, densitometric and biomechanical properties of teeth.

[Osteoporosis and oral diseases]

Osteoporosis is a major cause of fractures in elderly women. Bone densitometry is used in order to detect osteoporosis. It has been observed can also be analyzed in the jawbone. The osteoporosis may be associated with resorption of the residual ridge, periodontitis and tooth loss; also the same treatments can affect the jaws. A search was carried out in the Medline-Pubmed database in order to search the association between osteoporosis and oral diseases over the past 5 years. Forty-two articles were obtained after the selection process. The authors stated that: in reference to periodontal disease the results are conflicting, but there seems to be a higher prevalence of the disease and tooth loss and resorption of the crest. Oral bisphosphonates have little risk of causing osteonecrosis, and there is no relationship in the dental implant failure among patients taking bisphosphonates. There is no clear scientific evidence that could link osteoporosis and oral diseases.