Subchondral bone resorption in temporomandibular joint disorders

Osteoporosis and the risk of temporomandibular disorder in chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a major cause of chronic morbidity and mortality worldwide. The coexistence of COPD and temporomandibular disorder (TMD) has been noted, and dysfunctional mastication resulting from TMD can worsen individuals' nutritional status. This association between COPD and TMD has been rarely discussed in previous studies. Therefore, this study aimed to determine whether osteoporosis increases the risk of TMD in COPD and whether anti-osteoporosis medications can prevent TMD.

MATERIALS AND METHODS

This retrospective nationwide population-based study utilized the Taiwan National Health Insurance Research Database. We enrolled 52,652 COPD patients between 2000 and 2015: 13,163 with osteoporosis and 39,489 without osteoporosis. Groups of COPD patients with and without osteoporosis were age- and sex-matched. A multivariable Cox proportional hazards regression model was used to evaluate the risk of TMD development in COPD patients with and without osteoporosis over 15 years.

RESULTS

There was a higher risk of TMD occurrence in COPD patients with osteoporosis than in those without osteoporosis (adjusted hazard ratio 2.564, P < 0.001) after adjusting for demographic variables and associative comorbidities. Osteoporosis, hypertension, vertebral compression fracture, and nonpsychotic mental disorders were risk factors contributing to TMD development in patients with COPD. Anti-osteoporosis medications were associated with the prevention of TMD development concomitant with osteoporosis and COPD (adjusted hazard ratio 0.617, P = 0.004).

CONCLUSIONS

Patients with COPD and osteoporosis are at a higher risk of developing TMD, and anti-osteoporosis medications can prevent the development of TMD in this context.

Low skeletal bone mineral density as a potential aetiological factor towards idiopathic condylar resorption

The aim of this study was to investigate the contributing factor of impaired skeletal quality in the pathogenesis of idiopathic condylar resorption (ICR). One hundred and twenty-six patients with MRI-confirmed ICR and 596 patients with disc displacement (DD) without a diminished condyle, of both sexes, were included. Dental examinations and retrospective surveys regarding temporomandibular joint symptoms and progression of maxillofacial deformities were conducted. Skeletal bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and converted to T-scores and Z-scores. Results showed that ICR patients had a smaller overbite (1.56±3.3 vs 3.05±2.0mm), larger overjet (4.9±2.4 vs 3.5±1.9mm), larger range of mouth opening (36.5±6.7 vs 33.6±7.1mm), and higher rates of anterior open bite and mandibular retrusion compared to DD patients (all P<0.001). ICR was associated with an increased probability of low skeletal BMD at chronological age in females (P=0.020) but not in males (P=0.095). This study indicates that reduced BMD may predispose females to an exacerbated condylar resorption process in addition to increased joint loading initiated from DD.

The prevalence of first-onset temporomandibular disorder in low back pain and associated risk factors: A nationwide population-based cohort study with a 15-year follow-up

The coexistence of low back pain (LBP) and temporomandibular disorder (TMD) has often been noted clinically. However, studies of the association between these two conditions involving a large population with longitudinal evidences are lacking. Therefore, the study aimed to investigate the association between LBP and TMD in a nationwide-matched cohort population with a 15-year follow-up.Data of 65,121 patients newly diagnosed with LBP were analyzed, along with those of 195,363 (1:3) sex- and age-matched controls. Multivariate Cox regression analysis was used to determine TMD risk between the LBP and non-LBP groups. Kaplan-Meier method was used for determining the cumulative risk of first-onset TMD between groups, with a 15-year follow-up.The LBP group was more likely to develop first-onset TMD (adjusted hazards ratio (HR) = 1.561, P < .001), after adjusting for demographic variables and comorbidities. The risk factors for TMD were LBP, young age, higher insured premium, and osteoporosis. In the subgroup analysis, the LBP group had a higher risk of TMD than the non-LBP group in all stratifications.LBP is the risk factor contributing to the development of first-onset TMD. Therefore, clinicians should be reminded to manage LBP disorders concurrently when treating TMD.

Relation between osteoporosis and radiographic and clinical signs of osteoarthritis/arthrosis in the temporomandibular joint: a population-based, cross-sectional study in an older Swedish population

OBJECTIVE

The aim was to elucidate the relation between osteoporosis and osteoarthritis/arthrosis (OA) in the temporomandibular joint (TMJ).

BACKGROUND

General epidemiological data support the hypothesis that osteoporosis and OA are inversely correlated but is not conclusively investigated in the TMJ.

MATERIALS AND METHODS

A group of 114 representative elderly women and men, randomised from a comprehensive population study in Gothenburg, Sweden, had bone mineral density established with whole-body, dual-energy X-ray absorptiometry (DXA) as part of a health survey. In addition, dental examinations were performed, including panoramic radiographs exposed as an overview of the TMJ's and jaws. In 88 of the 80-year-old participants (48 women and 40 men), a clinical orofacial examination according to the RDC/TMD system was performed.

RESULTS

A diagnosis of osteopenia/osteoporosis was found in 36% of the 114, with a statistically different greater proportion of women. Condylar alterations evaluated from panoramic radiographs were observed in 34%, with no significant gender difference. No significant differences were found in the proportion of individuals with osteopenia/osteoporosis and any condylar radiographic alteration or not. Forty-one of the clinically examined subjects, 47%, fulfilled the criteria for an RDC/TMD diagnosis with no gender difference. All participants graded the orofacial pain as low chronic pain. An opening capacity of <40 mm denoted a higher risk of having pain in the temporomandibular system. No association was found between clinical diagnosis of RDC/TMD and osteopenia/osteoporosis.

CONCLUSION

The prevalence of osteopenia/osteoporosis appears not to be of importance for radiological or clinical findings of OA in the TMJ.

Progression of cartilage degradation, bone resorption and pain in rat temporomandibular joint osteoarthritis induced by injection of iodoacetate

Background

Osteoarthritis (OA) is an important subtype of temporomandibular disorders. A simple and reproducible animal model that mimics the histopathologic changes, both in the cartilage and subchondral bone, and clinical symptoms of temporomandibular joint osteoarthritis (TMJOA) would help in our understanding of its process and underlying mechanism.

Objective

To explore whether injection of monosodium iodoacetate (MIA) into the upper compartment of rat TMJ could induce OA-like lesions.

Methods

Female rats were injected with varied doses of MIA into the upper compartment and observed for up to 12 weeks. Histologic, radiographic, behavioral, and molecular changes in the TMJ were evaluated by light and electron microscopy, MicroCT scanning, head withdrawal threshold test, real-time PCR, immunohistochemistry, and TUNEL assay.

Results

The intermediate zone of the disc loosened by 1 day post-MIA injection and thinned thereafter. Injection of an MIA dose of 0.5 mg or higher induced typical OA-like lesions in the TMJ within 4 weeks. Condylar destruction presented in a time-dependent manner, including chondrocyte apoptosis in the early stages, subsequent cartilage matrix disorganization and subchondral bone erosion, fibrosis, subchondral bone sclerosis, and osteophyte formation in the late stages. Nociceptive responses increased in the early stages, corresponding to severe synovitis. Furthermore, chondrocyte apoptosis and an imbalance between anabolism and catabolism of cartilage and subchondral bone might account for the condylar destruction.

Conclusions

Multi-level data demonstrated a reliable and convenient rat model of TMJOA could be induced by MIA injection into the upper compartment. The model might facilitate TMJOA related researches.

Oral implications of osteoporosis

OBJECTIVES

The association between osteoporosis and oral health remains a matter of controversy. It is important to confirm whether there is a role of osteoporosis in bone loss in the jaws, periodontal diseases, tooth loss, and other oral tissue changes. The objective of this article is to review and summarize the published literature on the associations between osteoporosis and various oral conditions such as bone loss in the jaws, periodontal diseases, and tooth loss.

METHODS

A search of the computerized database MEDLINE was conducted. Clinical information concerning systemic osteoporosis and animal studies reporting possible associations between osteoporosis and changes in the dental and oral tissues were included. The review focus was on studies involving (1) methods for assessing bone mineral density (BMD); (2) methods for assessing osteoporosis-related changes in intraoral sites; (3) associations between mandibular BMD and skeletal BMD; (4) changes in the jaws, periodontal tissues, and temporomandibular joint concurrent with osteoporosis; (5) changes in the oral tissues following estrogen deficiency; and (6) effects of estrogen-hormone replacement therapy and/or calcium and vitamin D on oral health.

RESULTS

Ninety-seven studies conducted in various parts of the world were identified. Evidence from prospective studies supports the contention that individuals with osteoporosis may be at increased risk for the manifestations of oral osteoporosis; however, such risk is not definitively proven. Studies suggest that findings on dental panoramic radiographs may be used to detect individuals with low BMD.

CONCLUSIONS

Further well-controlled studies are needed to better elucidate the inter-relationship between systemic and oral bone loss and to clarify whether dentists could usefully provide early warning for osteoporosis risk.