Browsing by Author "Meyer, Mark Keith"

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    Assessment of pain perception linked to COMT-gene activity in diagnostic groups with temporomandibular joint disorders in a South African population
    (Universty of the Western Cape, 2023) Meyer, Mark Keith; Chetty, Manogari
    Pain affects a large segment of the population suffering from Temporomandibular Disorders (TMD). This persistent TMD pain may lead to physical, psychological, behavioral, and psychosocial symptoms. The chronicity of pain may be affected by genetic factors, and in the last decade much research was done investigating the impact of genetic factors and its relationship to pain perception. Several genes have been identified as potentially modulating TMD. The genes that have been identified to support the development of TMD include those related to the sensation of pain. Specific target genes associated to the catecholaminergic system, like the Catechol-O-Methyltransferase (COMT) gene, are linked to regulating the nociceptive process. The main objective of this study was to correlate pain perception in patients with TMD and the association with various COMT gene SNPs in a South African population. This study also assessed how various COMT gene SNPs impacts the psychosocial behaviour of patients suffering from TMD.
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    Correlating the intra-operative position of the inferior alveolar nerve with pre-operative cone- beam computer tomography in bilateral sagittal split osteotomies
    (University of the Western Cape, 2015) Meyer, Mark Keith; Morkel, A
    Aim: The aim of the study was to investigate whether a correlation exists between the intra- operative position of the Inferior Alveolar Nerve (IAN) and the nerve position as noted on a pre-operative Cone Beam Computer Tomography (CBCT) scan in patients requiring Bilateral Sagittal Split Osteotomy (BSSO) of the mandible. Introduction: The BSSO of the mandible is of fundamental importance in the correction of dental facial deformities. The main post-operative complication of a BSSO of the mandible is Neurosensory Impairment (NSI). To avoid possible NSI it is important to have as much pre- operative information as possible. In this regard, pre-operative CBCT scans can provide the surgeon with an important assessment of the mandibular canal. This information on the buccolingual, superior and inferior position of the canal, especially in the region of the planned osteotomy, could help the surgical team to avoid IAN injury. Materials and Methods: This study correlates the pre-operative position of the IAN as indicated on a CBCT scan with the intra-operative IAN position in patients requiring BSSO of the mandible. Ten standardised cases were included in a prospective case series where twenty mandibular sides were assessed. Results: The variables assessed in this study were location of the nerve, age, sex, type of movement and side of mandible operated on. It was found that only the distance between the Inferior Alveolar Canal (IAC) and the lower border of the mandible are predictive of whether the IAN will be attached to - or free from - the proximal segment of the mandible. Conclusion: From the study it can be concluded that a CBCT scan is a useful and reliable modality in the pre-operative evaluation of patients undergoing BSSO especially with regard to the assessment and mapping of the mandibular canal.
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    Investigating the association between Catechol-O-Methyltransferase gene activity and pain perception in South African patients with different temporomandibular disorders diagnoses
    (Multidisciplinary Digital Publishing Institute (MDPI), 2024) Chetty, Manogari; Meyer, Mark Keith; Ismail, Enas
    Background: Temporomandibular disorders (TMD) affect a significant portion of the population, with profound psychological, behavioral, and social repercussions. Recent investigations have explored the genetic basis underlying pain perception in individuals with TMD, aiming to elucidate the role of specific genetic factors in modulating the condition. Notably, genetic variations have been implicated in the pathogenesis of TMD, particularly genes involved in pain perception pathways. One of the primary candidates is the Catechol-O-Methyltransferase (COMT) gene, which plays a crucial role in the catecholaminergic system and has been associated with the regulation of nociceptive processes. This study seeks to investigate the correlation between COMT gene activity and pain perception among South African patients diagnosed with varying forms of TMD. Methodology: In this study, a total of 196 participants were enrolled, comprising 97 patients diagnosed with TMD and 99 control participants. The control group was meticulously matched with the TMD group for age, gender, and ethnicity. Data collection involved clinical and radiological investigations, and saliva sampling. The English version of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I was utilized to evaluate all TMD participants, focusing on standard diagnostic measures based on clinical signs and symptoms of TMD, which primarily describe common physical manifestations of the disorder. Genomic DNA was extracted from saliva samples, enabling the analysis of single-nucleotide polymorphisms (SNPs) in the COMT gene, specifically targeting polymorphisms rs165774, rs9332377, rs6269, rs4646310, rs165656, and rs4680. Results: The current study demonstrated a pronounced gender disparity, with 80.41% of the participants being female and 19.59% male, suggesting that women in South Africa either exhibit a higher susceptibility to TMD or are more likely to seek treatment for the condition compared to men. The highest prevalence of TMD was observed in the white population (58.76%). Additionally, over 65% of TMD patients were diagnosed with at least two Axis I diagnoses, a figure that increased to 89% for those diagnosed with three Axis I diagnoses. The findings further indicated significant associations between several single-nucleotide polymorphisms (SNPs) in the Catechol-O-Methyltransferase (COMT) gene—specifically rs165656, rs9332377, rs4646310, rs6269, and rs165774—and both TMD and TMD-related pain. Myofascial pain with referral and myalgia showed a strong association with the COMT SNPs rs9332377 and rs4646310. Furthermore, COMT SNP rs4646310 was also associated with disability related to TMD. Conclusions: This study substantiates the hypothesis that pain is prevalent in a considerable proportion of patients affected by TMD. Furthermore, the findings reveal a significant association between COMT gene activity and pain perception in South African patients diagnosed with TMD.