Association Between Polymorphisms in the Genes of Estrogen Receptors and the Presence of Temporomandibular Disorders and Chronic Arthralgia

Is there a superiority between arthrocentesis and stabilizing occlusal splint for the treatment of anterior disc displacement with reduction and intermittent block and anterior disc displacement without reduction in TMJ? Randomized clinical trial

INTRODUCTION

Anterior displacement of the temporomandibular joint (TMJ) disc is a disorder in which the articular disc is dislocated from its correct position relative to the mandibular condyle and mandibular fossa. Traditionally, the initial treatment of disc displacements involves various conservative measures, including the use of a stabilizing interocclusal splint. However, in cases where there is associated limited mouth opening, as in the case of anterior disc displacement with reduction and intermittent block (ADDwRIB), and anterior disc displacement without reduction (ADDw/oR), arthrocentesis has been suggested as another modality of initial treatment due to its faster effect in preventing disease progression to a more advanced stage, as well as reducing the chances of pain chronification and central sensitization.

OBJECTIVES

This study aimed to analyze whether there is a preponderance in efficacy between treatments with a stabilizing interocclusal splint or arthrocentesis in these patients.

METHODS

A randomized, prospective, longitudinal clinical trial was conducted. The sample was obtained by convenience, between June 2021 and January 2023. Twenty-four patients with diagnoses of ADDwRIB and ADDw/oR were included. The diagnosis and clinical evaluations followed the DC/TMD criteria, and TMJ MRI was performed. Patients were randomly allocated to 2 treatment groups. Group 1 (n = 13): stabilizing interocclusal splint. Group 2 (n = 11): arthrocentesis. Patients were evaluated after 1, 2, 3, and 6 months for clinical parameters of pain, functionality, and psychosocial status.

RESULTS

Both treatments were effective in reducing pain levels, with no statistically significant differences. Group 1 showed significantly greater mouth-opening levels compared to Group 2 (P = .041).

CONCLUSION

Both groups showed significant improvements in various parameters evaluated throughout the study, indicating they are equally effective in pain control and most functional and quality of life parameters. However, the stabilizing interocclusal splint treatment was superior in restoring mouth opening.

Psoriatic Arthritis Involving TMJ: A Review on Pathogenesis and Consideration on Eventual Gender Differences

Psoriatic arthritis is defined as chronic inflammatory arthritis associated with psoriasis. The current data regarding gender differences in clinical manifestation and therapeutic outcomes of psoriatic arthritis are limited. Generally, men show a peripheral disease manifestation, while women have an axial distribution of the lesions. If we look at temporomandibular joint (TMJ) involvement, epidemiological data on the involvement of the TMJ are hard to find. Few studies on therapeutic management and the related impact on the quality of life are reported in the literature. Given the morpho-functional peculiarities of the TMJ and the different pain burdens between male and female genders, when manifestation of psoriatic arthritis occurs, clinicians should face it using a multidisciplinary approach for a correct diagnosis and successful treatment. This review aims to examine the diagnostic signs of psoriatic arthritis in the TMJ, the eventual variations of this disease in male and female patients, and the therapeutical strategies. The coordination of different specialties is fundamental to the remission of clinical symptoms and lesion regression.

Genetic overlap between temporomandibular disorders and primary headaches: A systematic review

Primary headache disorders (PHD), specifically migraine, are strongly associated with temporomandibular disorders (TMD), sharing some patterns of orofacial pain. Both disorders have significant genetic contributions already studied. PRISMA guidelines were followed to conduct this systematic review, which comprehensively summarize and discuss the genetic overlap between TMD and PHD to aid future research in potential therapy targets. This review included eight original articles published between 2015 and 2020, written in English and related to either TMD and/or PHD. The genes simultaneously assessed in PHD and TMD studies were COMT, MTHFR, and ESR1. COMT was proved to play a critical role in TMD pathogenesis, as all studies have concluded about its impact on the occurrence of the disease, although no association with PHD was found. No proof on the impact of MTHFR gene regulation on either TMD or PHD was found. The most robust results are concerning the ESR1 gene, which is present in the genetic profile of both clinical conditions. This novel systematic review highlights not only the need for a clear understanding of the role of ESR1 and COMT genes in pain pathogenesis, but it also evaluates their potential as a promising therapeutic target to treat both pathologies.

Gender differences in Damp-Heat Syndrome: A review

Gender differences have important biological significance for medical research. In this study, a bias towards males was identified in animal experiments of Damp-Heat Syndrome in traditional Chinese medicine, as was first proposed by a data mining method. Combined with the correlation between Damp-Heat Syndrome in traditional Chinese medicine and Gender differences, it was considered that Gender-related factors have a significant influence on the development of Damp-Heat Syndrome in traditional Chinese medicine. However, most traditional Chinese medicine studies ignore the key significance of Gender-related factors. This study emphasises that the development of modern traditional Chinese medicine research needs to pay full attention to the biological significance of Gender-related factors and to apply this concept to the research on the Gender equivalence strategy in basic research and the practice of personalised medical diagnosis and clinical treatment.

Association of Estrogen Receptor 1 and Tumor Necrosis Factor α Polymorphisms with Temporomandibular Joint Anterior Disc Displacement without Reduction

Objectives

The aim of this study was to investigate the role of ESR1 rs1643821 and TNF-α rs1800629 as potential genetic factors regulating anterior disc displacement without reduction-mediated inflammatory pathway.

Background

The temporomandibular joint is a complex synovial joint that allows mandibular movement in three directions. Although temporomandibular disorders are widespread, limited data is available on the biochemical characteristics of the displaced disc and quality of the surrounding soft tissue. Changes in degenerative tissue provoke disc displacement which involves secretion of inflammatory markers and sequential conversion of fibroblast-like cells into chondrocyte-like cells. Due to the high occurrence in female adolescents, the potential role of sex hormones in temporomandibular joint disorders has been speculated. Furthermore, anterior disc displacement without reduction severely affects the quality of life.

Methods

124 Caucasian patients with a history of at least one anterior disc displacement without reduction within 3 months were enrolled. Anterior disc displacement without reduction was diagnosed based on clinical examination, diagnostic criteria (DC)/TMD, and cone-beam computed tomography/magnetic resonance imaging (CBCT/MRI). The control group consisted of 126 patients with no temporomandibular joint disorders. Genotyping of two single nucleotide polymorphisms, estrogen receptor 1 (ESR1) rs1643821, and tumor necrosis factor α (TNF-α) rs1800629 was performed.

Results

ESR1 rs1643821 showed significant P values (using chi-square analysis) revealing the difference in anterior disc displacement without reduction frequencies while TNF-α rs1800629 polymorphism was found to be statistically insignificant when compared to the control group. Furthermore, patients with a genotype of ESR1 rs1643821 showed a decreased probability (OR = 0.412) against anterior disc displacement without reduction when compared to the GG genotype (OR = 1).

Conclusion

ESR1 rs1643821 with A allele frequency was lower in patients with anterior disc displacement without reduction compared to the control group. Thus, the rs1643821 variant is significantly associated with susceptibility to the anterior disc displacement without a reduction in European Caucasians. Conversely, TNF-α rs1800629 was a statistically insignificant factor against anterior disc displacement without reduction when compared to the control group.

P2Y2 Receptors Mediate Masseter Muscle Mechanical Hypersensitivity in Rats

Purpose

P₂Y₂ receptors (P₂Y₂Rs) are among the various receptors that play an important role in nociception. The goal of this research was to investigate possible P₂Y₂R expression changes in the trigeminal ganglion (TRG) in bilateral masseter muscle (MM) hypersensitivity following unilateral MM inflammation. The impact of unilateral intramasseteric administration of P₂Y₂R antagonist on bilateral MM hypersensitivity was also explored.

Materials and Methods

Bilateral MM hypersensitivity was provoked by unilateral intramasseteric injection of complete Freund’s adjuvant (CFA). The head withdrawal threshold (HWT) was assessed bilaterally 4 days later. Bilateral TRG and MM isolation were followed, and quantitative real-time polymerase chain reaction (qRT-PCR) and histopathological analysis were carried out on these tissues, respectively. The involvement of P₂Y₂Rs in nocifensive behavior was evaluated by administering two doses of P₂Y₂R antagonist AR-C118925 (0.2 or 1 mg/100 μL) in inflamed MM 4 days post-CFA administration. Bilateral HWT was assessed at different time points following antagonist injection.

Results

qRT-PCR analysis demonstrated P₂Y₂R up-regulation in TRG ipsilateral to the site of CFA administration. Compared to the controls, both doses of AR-C118925 injected ipsilateral to the TRG increased the bilateral HWT at 30, 60, 90, and 120 minutes after antagonist administration.

Conclusion

The findings suggest that P₂Y₂Rs may affect MM inflammatory hypersensitivity owing to its up-regulation in the TRG in MM inflammatory pain states.

Morphology of the Temporomandibular Joints Regarding the Presence of Osteoarthritic Changes

(1) Osteoarthritis, the most common disease of the temporomandibular joints (TMJs), is diagnosed by clinical and radiographic examination. Cone beam computed tomography (CBCT) is a method of choice for the imaging of osteoarthritic changes. The objective was to compare the morphology of the TMJs in CBCT images regarding the number of the osteoarthritic changes diagnosed in the area of the condyle. (2) A total of 105 patients participated in the study; their 210 TMJs were allocated into one of three groups regarding the number of diagnosed osteoarthritic changes: 1 (none or 1 type), 2 (2 types), 3 (3 or more types). The morphology of the TMJ was examined for each TMJ in the CBCT images. Statistical analysis was performed with STATISTICA version 12.0. The statistical significance level was p = 0.05 for all the measurements included. (3) The articular surface flattening was the most common type of the osteoarthritic changes (90%). The condylar A-P dimension differed significantly among the groups (p = 0.0001). The bigger the number of osteoarthritic changes diagnosed in one joint, the smaller the condylar A-P dimension that was observed. (4) The temporomandibular joints’ osteoarthritic changes occur very often, even among asymptomatic patients. The increased number of osteoarthritic changes seems to have an impact on the condylar anteroposterior dimension.

Association between oestrogen receptors and female temporomandibular disorders

Objective: To evaluate if temporomandibular disorders (TMDs) are associated with genetic polymorphisms in ESR1 and ESR2, which are genes encoding oestrogen receptor alpha (ERα) and beta (ERβ). Also, we included an animal model to check if ERα and ERβ are expressed in the temporomandibular joint (TMJ) during adolescence.Materials and methods: A total of 139 teenagers and 93 adults were diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMDs). The DNA was collected and the markers ESR1 and ERS2 were genotyped. Additionally, immunohistochemistry was performed in TMJ tissues from female Wistar rats during puberty. All data were submitted to statistical analysis with confidence interval of 95%.Results: Teenagers presented more disc displacement and arthralgia than adults (p < .05). The genetic polymorphism rs1256049 in ESR2 was associated with disc displacement (p = .040; OR = 10.50/95%CI 1.17-98.74) and arthralgia (p = .036; OR = 7.20/95%CI 1.10-46.88) in adults. The ERα and ERβ are expressed in rat TMJ tissues.Conclusions: We provide evidence that ESR2 is associated with TMD and could be a genetic marker for this condition in adult women. Furthermore, oestrogens receptors are presented in TMJ of adolescent female rats.

Classification of the journal category "oral surgery" in the Scopus and the Science Citation Index Expanded: flaws and suggestions

Objectives

The aim of this study was to evaluate the journal category “oral surgery” in Scopus and in the Science Citation Index Expanded (SCIE).

Materials and Methods

The Journal of Oral and Maxillofacial Surgery (JOMS), The Journal of the Korean Association of Oral and Maxillofacial Surgeons (JKAOMS), and The Journal of Prosthodontic Research (JPR) were selected from the Scopus list of journals as oral surgery journals. Maxillofacial Plastic and Reconstructive Surgery (MPRS) was selected from PubMed as a Scopus oral surgery title. From these titles, 10 recently published articles were collected and used for reference analysis.

Results

The percentage of citations from oral surgery journals was 26.7%, 24.5%, and 40.1% for JKAOMS, MPRS, and JOMS, respectively. In total, 1.1% of JPR's citations were from oral surgery journals and significantly fewer from other journals (P<0.001). The percentage of citations from dentistry journals excluding oral surgery journals was 11.9%, 34.4%, and 15.8% for JKAOMS, MPRS, and JOMS, respectively. For JPR, 80.6% of citations were from dentistry journals and significantly more were from other journals (P<0.001).

Conclusion

Selected samples revealed that JPR is incorrectly classified as an oral surgery journal in Scopus. In addition, the scientific interaction among JKAOMS, MPRS, and JOMS was different to JPR in the reference analysis.

Dental genetics in Brazil: Where we are

Dentistry constitutes the basic nucleus of professionals of higher level of health in Brazil with one of the largest concentrations of dentists per capita in the world. However, the genetic in dentistry in Brazil is explored, basically, in research field. Future actions need to be performed in order to deep the whole knowledge about diagnosis and treatment of diseases with genetic basis in dentistry, in Brazil.