Pattern analysis of patients with temporomandibular disorders resulting from unilateral mastication due to chronic periodontitis

Changes of the condylar cartilage and subchondral bone in the temporomandibular joints of rats under unilateral mastication and expression of Insulin-like Growth Factor-1

OBJECTIVES

This study aimed to define changes in the rat condylar cartilage and subchondral bone using the unilateral mastication model.

MATERIALS AND METHODS

In this study, forty 4-week-old Wistar rats were randomly divided into experimental (n = 20) and control group (n = 20). In the experimental group, unilateral dental splints were placed on the occlusal surface of left maxillary molars. The rats were sacrificed at 1, 2, 3, and 4 weeks after placement of the splint. Micro-CT scanning and histological staining were performed to observe the changes in the mandibular condylar cartilage and subchondral bone. Levels of insulin-like growth factor-1 (IGF-1) were determined via immunohistochemistry to analyse the occurrence of osteogenic changes.

RESULTS

Micro-CT scanning findings demonstrated the occurrence of asymmetric growth of condyle in the experimental group. The condylar cartilage and subchondral bone exhibited degradation on the chewing side of the experimental group and showed decreased bone mineral density, thinner cartilage thickness, and increased degree of degeneration and osteoclast activity. Compared with the control group, the expression of IGF-1 was remarkably higher on the non-chewing side.

CONCLUSION

Long-term unilateral mastication can lead to the occurrence of degenerative changes in the condylar cartilage and subchondral bone during growth and development. IGF-1 may play a role in promoting the process of osteogenesis.

Fibromyalgia and periodontitis: Bidirectional associations in population-based 15-year retrospective cohorts

BACKGROUND

To determine the bidirectional link between periodontitis and fibromyalgia.

METHODS

In this cohort study, 196,428 periodontitis patients and 196,428 propensity score-matched non-periodontitis controls were enrolled. A Cox proportional hazard model was utilized to estimate the risk of fibromyalgia and survival analysis was adopted to assess the time-dependent effect of periodontitis on fibromyalgia. Subgroup analyses stratified by age, sex, and tracking period were conducted to identify susceptible populations. A parallel and symmetrical cohort that recruited 141,439 fibromyalgia patients and 141,439 propensity score-matched non-fibromyalgia controls ascertained the inverse effect of fibromyalgia on incident periodontitis.

RESULTS

Patients with periodontitis were more likely to develop fibromyalgia than non-periodontitis controls (HR = 1.42, 95% CI = 1.39-1.44, P < 0.001), which persisted in the survival analysis (log-rank test P < 0.0001). This effect was significant in both sexes and all age subgroups, and was particularly evident in males (HR = 1.52, 95% CI = 1.48-1.56, P < 0.001) and younger periodontitis patients (HR = 1.55, 95% CI = 1.50-1.60, P < 0.001). Fibromyalgia patients who never had periodontitis presented with greater risk for periodontitis over time (HR = 1.43, 95% CI = 1.40 - 1.45, P < 0.001; log-rank test P < 0.0001).

CONCLUSIONS

Patients of both sexes and all age subgroups with periodontitis presented with a greater risk of fibromyalgia. Subgroups that were the most susceptible to periodontitis-associated fibromyalgia were periodontitis patients that were males and below 30 years old. Risks of periodontitis were also greater in fibromyalgia patients who never had periodontitis.

Comparative Analysis of the Temporomandibular Joints in Patients with Chronic Periodontitis Using Cone-Beam Computed Tomography (CBCT)

INTRODUCTION

Chronic periodontitis is a common disorder in adults causing periodontal destruction and loss of teeth. These clinical presentations may lead to temporomandibular joint disorders (TMDs). This study aimed to examine the anatomic structures of the temporomandibular joints (TMJs) using cone-beam computed tomography (CBCT) in patients with chronic periodontitis.

METHODS

Fifty patients with chronic periodontitis were enrolled in the study. Based on the severity of chronic periodontitis, these patients were divided into the mild, moderate, and severe groups. CBCT images of TMJs were acquired and reconstructed. Several indices on the reconstructed CBCT images were collected and analyzed, such as the oblique joint space parallel to the long axis of the condyle, the long axis diameter of the condyle, the vertical angle of the condyle, the inclination of the articular eminence vertical to the long axis of condyle at the oblique and sagittal positions, the depth of the fossa, and the horizontal angle of the cross-sections. The measurements between right and left sides of each patient were compared. Statistical analysis (paired samples t test) was performed.

RESULTS

The differences of the joint space vertical to the bilateral condyles were statistically significant (P < 0.05). Additionally, in the severe periodontitis group, the distances between the inner and outer poles of the condyles were statistically different (P < 0.05).

CONCLUSION

In patients with chronic periodontitis, TMJ space vertical to the condyles and the distances between the outer and inner poles of the condyle may change over time. These two indices can potentially be used as indicators for diagnosis and further comparative analyses.

Cone beam computed tomography findings in temporomandibular joint of chronic qat chewers: Dimensional and osteoarthritic changes

The social habit of chewing qat (also known as khat) is widely practised in East Africa and the Arabian Peninsula. It has been linked with various oro-facial conditions, including temporomandibular joint disorders (TMD). This cross-sectional, comparative study sought to investigate the effects of qat chewing on temporomandibular joint (TMJ), using cone beam computed tomography (CBCT). A total of 85 Yemeni males were included. The participants were divided into two groups: Qat chewers (QC; n = 41) and non-qat chewers (NQC; n = 44). Relevant data were obtained using a structured questionnaire and standardised clinical examination. Additionally, CBCT images of the TMJs were obtained, and then, osteoarthritic changes and TMJ dimensions were analysed. SPSS 21 was used for statistical analyses, with a significant level was set at 0.05. Compared to NQC, a significantly higher proportion of QC presented with clinical signs of TMDs. The qualitative CBCT findings revealed significantly higher osteoarthritic changes in QC than in NQC: osteophyte (51.2% vs 22.7%; P = .008), subcortical sclerosis (48.8% vs 27.3%; P = .047), articular surface flattening (46.3% vs 6.8%; P = .009) and subcortical cysts (43.9% vs 4.5%; P < .001). However, CBCT quantitative findings (condylar dimensions) did not show significant differences between the two groups. The chewing side of the QC group showed slightly more changes compared to the non-chewing side. The results demonstrate that qat chewing has detrimental effects on TMJ manifested mainly as osteoarthritic changes. Further large-scale studies are recommended.

Aquaporin locus (12q13.12) might contribute to susceptibility of temporomandibular joint disorder associated with periodontitis

Aquaporins (AQPs) are membrane channels that provide for transport of water and other small molecules across the lipid bilayer of cells. Their function is essential for physiologic processes such as cell volume regulation, chondrocyte hypertrophy during appendicular skeletal growth, water reabsorption in the kidney tubules, and water excretion by the salivary glands. The ten AQP isoforms show tissue specificity and are involved in different pathologies and inflammatory diseases. This study addresses the hypothesis that arthritis, periodontitis, and temporomandibular joint disorders (TMDs) can be influenced by variation in the AQP genes at 12q13.12 locus. Salivary samples of 688 individuals were obtained from the Dental Registry and DNA Repository project at the University of Pittsburgh. Ten polymorphisms in four AQP genes (AQP1, 2, 5, and 6) were genotyped and correlated to disease status as reported by patients. Associations were found between the single nucleotide polymorphism (SNP) rs467323 in AQP2 and TMD in both genotypic (p = 0.03) and recessive (p = 0.02) models, and between rs1996315 in AQP6 and periodontitis (p = 0.05). Combined analysis of TMD and periodontitis showed an association with rs3741559 in AQP2 (p = 0.02). When conducting haplotype analysis of rs467323 and rs10875989 in AQP2, the haplotype CT showed an association with the TMD phenotype (p = 0.007). Our results suggest that the aquaporin locus at 12q13.12 may contribute to the pathogenesis of inflammatory conditions such as periodontitis and TMD. Thus, oral and skeletal health are correlated and potential susceptibility screening strategies may be developed.

Changes in masticatory laterality 3 months after treatment with unilateral implant-supported fixed partial prosthesis

OBJECTIVE

This study assessed changes in masticatory laterality in patients with unilateral posterior missing teeth 3 months after treatment with an implant-supported fixed partial prosthesis (ISFPP).

METHODS

Thirty patients with unilateral posterior missing teeth participated in this prospective study. They were treated with one-, two- or three-unit ISFPPs. The control group comprised 10 healthy individuals with complete natural dentition. Each participant performed masticatory assays at baseline and at 3-month follow-up, chewing pieces of silicon inside a latex bag. Masticatory laterality was determined using three different methods: assessment of the first chewing cycle, of all cycles and application of a visual analogue scale. Data were compared using the Kruskal-Wallis or the Mann-Whitney U test as appropriate.

RESULTS

Three months after treatment, a significant change in the asymmetry index towards the treated side and a significant reduction in the Unilateral Chewing Index were observed in the ISFPP group. No significant differences in masticatory laterality between groups were detected at 3-month follow-up, regardless of the method assessed.

CONCLUSION

Treatment with ISFPPs alters the masticatory laterality, moving it to the treated side and increasing the degree of bilateral chewing in patients with unilateral posterior missing teeth.