Relationship between mandibular inferior cortex and general bone metabolism in older adults

Repercussions of osteoporosis on the maxillofacial complex: a critical overview

INTRODUCTION

We present here a literature review focusing on the repercussions of osteoporosis on the oral and maxillofacial complex. Osteoporosis is a silent metabolic disorder characterized by reduced bone mineral density (BMD), which can lead to bone fractures, particularly affecting elderly women. The prevalence of this disease has increased significantly worldwide, and since it accelerates bone resorption also in the jaw bones, some attention has been paid to possible oral and maxillofacial manifestations.

MATERIALS AND METHODS

The databases PubMed and Google Scholar were searched for reports of oral and maxillofacial changes related to osteoporosis.

RESULTS

Several parameters evaluating bone changes in panoramic radiography have been proposed to estimate osteoporosis-related BMD loss, but they tend to warn about the possibility of osteoporosis, rather than being diagnostic criteria. Meanwhile, it seems that osteoporosis-related BMD loss could delay alveolar bone healing and potentiate bone loss in periodontal disease.

CONCLUSION

Even though orofacial bones are not compromised by osteoporosis as much as the axial/appendicular skeleton, a regular dental follow-up of osteoporotic patients is advised, especially in the case of periodontal disease and maxillofacial surgery. Further controlled longitudinal studies considering the site-specificity of osteogenesis would be helpful regarding this issue.

Clinical guidelines for the application of panoramic radiographs in screening for osteoporosis

Osteoporotic fractures are associated with an increased risk of subsequent fractures, a higher rate of mortality, and incremental medical costs. Incidental findings, which include some measurements related to the mandibular inferior cortex and the alveolar trabecular bone pattern of the mandible determined on panoramic radiographs, are considered to be a useful tool for identifying asymptomatic individuals at risk of having osteoporosis and/or fragility fractures. We undertook a worldwide literature survey and present the following clinical recommendations. Postmenopausal female dental patients with a mandibular inferior cortical width of less than 3 mm on panoramic radiographs may be at risk of having low skeletal bone mineral density (BMD) or osteoporosis, but not fragility fractures. In addition, those with a severely eroded mandibular inferior cortex may have an increased risk of having low skeletal BMD, osteoporosis, and fragility fractures. The alveolar trabecular bone pattern of the mandible might be useful for identifying female dental patients at risk of having fragility fractures, although further investigation is necessary to confirm this possibility. These incidental findings on panoramic radiographs, when used for identifying asymptomatic postmenopausal female patients at risk of having osteoporosis in general dental practice, may be helpful in reducing the incidence of first fractures, with a consequent reduction in the secondary fractures, medical costs, and mortality associated with osteoporotic fragility fractures, without incurring any additional cost.

Comparison of mandibular index values determined from standard panoramic versus cone beam computed tomography reconstructed images

OBJECTIVE

The aim of this study was to compare mandibular index values, including the mandibular cortical index (MCI), mental index (MI), and panoramic mandibular index (PMI), determined on the basis of cone beam computed tomography (CBCT) and panoramic reconstructed (PR) images.

STUDY DESIGN

PR and CBCT images of 182 patients were retrospectively analyzed. Cross-sectional (CS) and PR images were obtained from CBCT data. The MCI, MI, and PMI were assessed on CS, PR, and panoramic images and evaluated for intra- and interobserver agreements by κ-value or intraclass correlation coefficient (ICC) analysis. Agreement among measurement methods was assessed by using the Bland-Altman method, with CS images as the gold standard for linear measurements.

RESULTS

Measurements from PR and CS images agreed with those from panoramic images in 66.7% and 53.8% of C3 classifications of MCI (porous cortices forming many endosteal residues), respectively. Panoramic and CBCT images exhibited good agreement in MI findings (ICC 0.91) and moderate (PR and panoramic images: ICC 0.79) to good (CS and panoramic images: ICC 0.87) agreement in PMI findings.

CONCLUSIONS

Because of the overlapping of buccal and lingual cortices, panoramic images are especially inadequate for determining the C3 category of MCI. However, CS images obtained from available CBCT data provide better visibility compared with panoramic images and, therefore, can be used for evaluating mandibular indices.

Pamidronate affects the mandibular cortex of children with osteogenesis imperfecta

We hypothesized that mandibular cortical width (MCW) is smaller in children with osteogenesis imperfecta (OI) than in healthy children and that pamidronate can improve the cortical mandibular thickness. The aim of this study was to assess changes in the MCW on dental panoramic radiographs (DPRs) of children with normal bone mineral density (BMD) and with OI. We also compared the MCW of children with different types of OI regarding the number of pamidronate cycles and age at the beginning of treatment. MCW measurements were retrospectively obtained from 197 DPRs of 66 children with OI types I, III, and IV who were in treatment with a comparable dosage of cyclical intravenous pamidronate between 2007 and 2013. The control group had 92 DPRs from normal BMD children. Factorial analysis of variance was used to compare MCW measurements among different age groups and between sexes and also to compare MCW measurements of children with different types of OI among different pamidronate cycles and age at the beginning of treatment. No significant differences in results were found between male and female subjects in both OI and healthy children, so they were evaluated altogether (P > 0.05). There was an increase of MCW values related to aging in all normal BMD and OI children but on a smaller scale in children with OI types I and III. Children with OI presented lower mean MCW values than did children with normal BMD at the beginning of treatment (P < 0.05). A linear model estimated the number of pamidronate cycles necessary to achieve mean MCW values equivalent to those of healthy children. The thinning of the mandibular cortex depended on the number of pamidronate cycles, the type of OI, and the age at the beginning of treatment. DPRs could thus provide a way to identify cyclic pamidronate treatment outcomes in patients with OI.

Mandibular inferior cortex erosion as a sign of elevated total serum calcium in elderly people: a 9-year follow-up study

OBJECTIVES

The mandibular inferior cortex (MIC) classification that was determined by observing the mandible distally from the mental foramen in panoramic radiography can be considered to reflect bone loss in the jaws. The purpose of this 9-year study was to investigate whether there is a relationship between MIC condition and total serum calcium (TSC) in elderly Japanese people.

METHODS

A total of 280 subjects aged 70 years at baseline (137 males and 143 females) took part in this longitudinal study design. TSC and dental panoramic radiographs were carried out at the baseline in 1998 and the final year in 2007.

RESULTS

The results of the MIC measurement were divided into two groups according to changes in MIC after the 9-year study period, namely no change group and change group. A significant relationship was found in females but not in males between the MIC condition and the TSC. The regression showed that female subjects are 3.26 times more likely to have increased erosion of the inferior border of the mandible than male subjects after the 9-year study period.

CONCLUSIONS

These results suggest that an increase in erosion of the inferior border of the mandible was significantly associated with an elevated TSC after 9 years and only in females.

The ability of H1 or H2 receptor antagonists or their combination in counteracting the glucocorticoid-induced alveolar bone loss in rats

BACKGROUND

The aim of the present study was to compare between three possible osteoporotic treatments in prevention of glucocorticoid-induced alveolar bone loss.

METHODS

Fifty adult female Wistar rats with an average weight 150-200 g were randomized into five groups: group I (control) was intraperitoneally injected with saline. The other experimental groups (II & III, IV & V) were intraperitoneally injected with 200 µg/100 g body weight dexamethasone. The experimental groups III, IV and V received intraperitoneal injection of 10 mg/kg/day pheniramine maleate (H1 receptor antagonist), ranitidine hydrochloride (H2 receptor antagonist) and concomitant doses of both H1 & H2 receptor antagonists respectively. After 30 days, the rats have been sacrificed. The mandibles were examined histologically, histochemically and histomorphometrically. The bone mineral density was measured using dual-energy X-ray absorptiometry (DEXA).

RESULTS

Histopathologically the glucocorticoid group showed wide medullary cavities with wide osteocytic lacunae. These marrow cavities were reduced in the prophylactic groups (III, IV) but increased in group V. Bone histomorphometric analysis revealed improvement in static bone parameters in groups III and IV and deterioration in group V in comparison to group II. The DEXA revealed significant reduction in the bone mineral density in all experimental groups compared to the control group.

CONCLUSIONS

In a rat model, the administration of H1 or H2 receptor antagonists separately could minimize the alveolar bone loss caused by the administration of glucocorticoids while concomitant administration of both H1 and H2 receptor antagonists deteriorated the bone condition.

Facial bone density: effects of aging and impact on facial rejuvenation

BACKGROUND

Facial bone aging has recently been described as primarily resulting from volume loss and morphologic changes to the orbit, midface, and mandible.

OBJECTIVE

The authors demonstrate how the facial skeleton bone mineral density (BMD) changes with age in both men and women and compare these changes to those of the axial skeleton. They also explore the aesthetic implications of such changes in bone density.

METHODS

Dual-energy X-ray absorptiometry (DXA) scans of the facial bones and lumbar spine were obtained from 60 white subjects, 30 women and 30 men. There were 10 men and 10 women in each of 3 age categories: young (20-40 years), middle (41-60 years), and old (61+ years). The following measurements were obtained: lumbar spine BMD (average BMD of L1-L4 vertebrae), maxilla BMD (the average BMD of the right and left maxilla), and mandible BMD (the average BMD of the right and left mandibular ramus).

RESULTS

The lumbar spine BMD decreased significantly for both sexes between the middle and old age groups. There was a significant decrease in the maxilla and mandible BMD for both sexes between the young and middle age groups.

CONCLUSIONS

Our results suggest that the BMD of the face changes with age, similar to the axial skeleton. This change in BMD may contribute to the appearance of the aging face and potentially affect facial rejuvenation procedures.

Relationship between bone turnover biomarkers, mandibular bone mineral density, and systemic skeletal bone mineral density in premenopausal and postmenopausal Indian women

OBJECTIVE

Postmenopausal osteoporosis is one of the most common metabolic bone disorders. Osteoporosis is reported to cause bone loss in the alveolar processes of maxilla and mandible, which provide bony framework for tooth anchorage. However, the association between systemic osteoporosis and oral health remains controversial. Available evidence suggests that Indian women have lower peak bone mass than their Western/other Asian counterparts. The present study evaluated the relationship between mandibular bone mineral density (mBMD), systemic skeletal BMD, and bone metabolism in premenopausal and postmenopausal Indian women.

METHODS

One hundred twenty-four premenopausal and 247 postmenopausal healthy women were included in the study. The BMD of the body of mandible, radius ultradistal, total hip, femur neck, and lateral spine were measured using dual-energy x-ray absorptiometry. Serum and urine biomarkers were determined using commercial kits.

RESULTS

Univariate regression analysis followed by stepwise multivariate regression analysis to obtain the best fit model demonstrated the BMD of radius ultradistal, serum inorganic phosphorus, estradiol, and sex hormone-binding globulin as significant predictors of mBMD in premenopausal women. The BMD of femur neck, serum ionized calcium, bone-specific alkaline phosphatase, osteocalcin, and urine total pyridinoline were significantly associated with mBMD in postmenopausal women. The significant association between mBMD and number of teeth present was observed in the whole group of premenopausal and postmenopausal women.

CONCLUSIONS

Varied predictors of mBMD were observed in premenopausal and postmenopausal women. The results suggest that the screening for these biomarkers and serum ionized calcium should be useful (1) to assess the status of mBMD particularly in women requiring surgical dental intervention that include bone manipulation and (2) for early detection and management of women with the risk of developing osteoporosis.

Association between periodontitis and systemic bone mineral density in Japanese community-dwelling postmenopausal women

OBJECTIVE

The purpose of this cross-sectional study was to evaluate the association between loss of attachment (LA) which is clinical index of periodontitis and bone mineral density (BMD) of the lumbar vertebrae and femur measured with dual energy X-ray absorptiometry (DXA) in Japanese community-dwelling postmenopausal women.

SUBJECTS AND METHODS

Subjects were 374 [corrected] women aged 55-74. The oral cavity was divided into 6 areas according to the WHO's method for the determination of the clinical attachment level score (CALscore); the LA was measured at 6 sites using a WHO probe in 17, 16, 11, 26, 27, 37, 36, 31, 46, and 47, and the values were recorded in mm. Then, we assessed BMD of the lumbar vertebrae (L2-L4) and femur (femoral neck, proximal part) by DXA. Based on these data, analysis of covariance was used to estimate relation between periodontitis and systemic BMD status excluding effect of age. Multiple linear regression analysis was used to estimate relation between periodontitis and BMD adjusted for 17 variables.

RESULTS

Significant differences were observed in the mean value between the mean CALscore=0 and CALscore≥1 groups in the Z value in lumbar vertebrate (106.9±18.7 vs. 102.3±1.0, p<0.05, t-test). Multiple regression analysis was conducted using the mean LA as dependent variable. Lumbar vertebral BMD (regression coefficient: B=-1.039±0.379, p=0.007), femoral neck BMD (B=-1.332±0.627, p=0.034), and proximal femoral BMD (B=-1.329±0.536, p=0.014) all exhibited a significant negative correlation with the mean LA.

CONCLUSION

A significant negative correlation was observed between periodontal disease and truncal bone BMD in this study.

Radiological and histologic studies of the mandibular cortex of ovariectomized monkeys

OBJECTIVE

The objective was to study the radiological and histologic changes in the mandibular cortices of ovariectomized monkeys.

STUDY DESIGN

Twelve female, adult, Cynomolgus monkeys (Macaca fascicularis) were used. Under anesthesia, 1 group was bilaterally ovariectomized (OVX), and the other (control group) underwent sham surgery. Seventy-six weeks after surgery, the monkeys were humanely killed, their mandibles were excised, and their mandibular inferior cortices (MIC) and adjacent cortices were examined histologically and with panoramic radiographs and micro computed tomography.

RESULTS

Striped shadows were seen on the endosteal side of the OVX cortices on panoramic radiographs. Histologic observation revealed many enlarged pores with eroded surfaces and calcein labeling (indicating osteon remodeling) in the OVX cortices.

CONCLUSIONS

In the MIC and adjacent cortices of OVX monkeys, enlarged Haversian canals were seen and there were indications of a high rate of bone turnover. The enlarged Haversian canals resulted in striped shadows and unclear endosteal margins on radiographic images.

The effect of hierarchical micro/nanosurface titanium implant on osseointegration in ovariectomized sheep

Hydrofluoric etching and anodized hierarchical micro/nanotextured surface titanium implant was placed in mandibles of ovariectomized sheep for 12 weeks, and it showed improved osseointegration by resonance frequency analysis (RFA), microcomputed tomography (micro-CT) evaluation, histomorphometry, and biomechanical test.

INTRODUCTION

This study aimed to investigate the effects of micro/nanotextured titanium implant on osseointegration in ovariectomized (OVX) sheep.

METHODS

The hierarchical micro/nanotextured surface of titanium implant was fabricated by acid in 0.5% (w/v) hydrofluoric (HF) and anodized in HF acid electrolytes with a DC power of 20 V, and the machined surface implants with no treatment served as control group. The implants were placed in mandibles of OVX sheep, respectively. Twelve weeks after implantation, RFA, microcomputed tomography, histomorphometry, and biomechanical tests were applied to detect the osseointegration of the two groups.

RESULTS

The implant stability quotient (ISQ) values, the maximum pull-out forces, and the bone-implant contact (BIC) were 65.5 ± 6.3, 490.6 ± 72.7 N, and 58.31 ± 5.79% in the micro/nanogroup and 58.3 ± 8.9, 394.5 ± 54.5 N, and 46.85 ± 5.04% in the control group, respectively. There was no significant difference between the two groups in ISQ values (p > 0.05), but in the micro/nanogroup, the maximal pull-out force and the BIC were increased significantly (p < 0.05 or p < 0.01). Micro-CT analysis showed that the bone volume ratio and the trabecular number increased significantly (p < 0.01), and the trabecular separation decreased significantly (p < 0.05) in the micro/nanogroup.

CONCLUSION

Implant modification by HF acid etching and anodization to form a hierarchical micro/nanotextured surface could improve titanium implant osseointegration in OVX sheep 12 weeks after implantation.

Validity of prevention of glucocorticoid-induced alveolar bone loss in rat by either calcitonin or alendronate administration

OBJECTIVE

The aim of the present study was to compare between two osteoporotic treatments in prevention of glucocorticoid-induced osteoporosis.

DESIGN

Forty adult male Wistar rats with an average weight of 150-200g were randomized into 4 groups, control, glucocorticoid administration, glucocorticoid administration with concomitant administration of calcitonin or alendronate. After 60 days, the rats were sacrificed. The mandibles were examined histologically, histomorphometrically, radiographically and ultrastructurally.

RESULTS

Histopathologically the glucocorticoid group showed irregular bone trabeculae with wide and abundant medullary cavities. These marrow cavities were reduced in the other prophylactic groups (III and IV). Histomorphometric analysis showed significant reduction in area percentage of alveolar bone trabeculae in glucocorticoid group (p=0.0025), while group IV showed significant increase in the area percentage of bone compared to the group I (p=0.0003). Radiographic analysis showed significant decrease in the alveolar bone density of group II at line 1 when compared to group I (p=0.0009). Moreover, significant reduction in bone density was detected in both groups II and III at line 2 when compared to the group I (p=0.007, 0.0273). Ultrastructurally, disorganized wide osteocyte lacunae and Haversian canals were observed in group II. However, group IV showed almost complete obliteration of Haversian canals as well as osteocytic lacunae.

CONCLUSIONS

In a rat model the administration of anti-osteoporotic drugs prevents the bone loss caused by the administration of glucocorticoids.

Relationship between the mandibular inferior cortex and bone stiffness in elderly Japanese people

SUMARRY: This study assessed the relationship between the mandibular inferior cortex (MIC) and bone stiffness in elderly Japanese subjects. Results suggest that MIC classification may be useful for screening patients for the possibility of osteoporosis by measuring bone stiffness with ultrasound bone densitometry.

INTRODUCTION

The prevention of fractures is a priority for patients with osteoporosis. Dental panoramic radiographs are frequently taken for the examination of teeth and jaws in general dental practice worldwide. This study assessed the relationship between the mandibular inferior cortex (MIC) and bone stiffness in elderly Japanese subjects.

METHODS

This study included 519 healthy subjects (263 men and 256 women) aged 70 years old. We evaluated the relationship between MIC classification and bone stiffness using Scheffe's multiple comparison test. Multiple linear regression analysis was used to assess the relationship between MIC classification and bone stiffness after controlling for confounding factors.

RESULTS

A significant correlation was found between MIC classification and bone stiffness in men (C1 vs C2: p < 0.05) and women (C1 vs C2: p = NS, C1 vs C3: p < 0.01, C2 vs C3: p < 0.05). MIC classification was significantly associated with bone stiffness on multiple linear regression analysis after controlling for sex, body mass index, regular exercise, and smoking (beta = -0.11, p < 0.01, R(2) = 0.387, p < 0.001).

CONCLUSIONS

Our study suggests that MIC classification may be useful for screening patients for the possibility of osteoporosis by measuring bone stiffness with ultrasound bone densitometry.

Triage screening for osteoporosis in dental clinics using panoramic radiographs

Many patients with osteoporosis go undiagnosed because typically no symptoms are present before a fracture. Triage screening to refer patients to appropriate medical professionals for further investigation would be useful to address the increase in the incidence of osteoporotic fractures. Dental clinics may offer a new triage screening pathway because dentists frequently take radiographs of bones in the course of dental treatment. A major premise for such triage screening in dental clinics is that dentists can readily use a screening tool in their dental practice. For example, cortical width and shape of the mandible detected on panoramic radiographs may be appropriate indices for triaging individuals with osteoporosis. To date, several investigators have demonstrated significant associations between cortical indices on panoramic radiographs and bone mineral density of the skeleton generally, such as the spine and femur, biochemical markers of bone turnover and risk of osteoporotic fractures. Further, in two recent Japanese clinical trials, approximately 95% of women who were identified by trained dentists in their clinics using cortical shape findings did have osteopenia or osteoporosis. These findings support the possibility that dental clinics may offer a new triage platform to identify individuals with otherwise undetected osteoporosis.