Potential influence of genetic variants in temporomandibular disorders

O presente estudo teve como objetivos testar a hipótese nula de que não há diferença entre o grupo com Disfunção Temporomandibular (DTM) e o grupo Controle, para as frequências genotípicas e de alelos dos SNPs candidatos COMT Val(158)Met (rs4680); TNFA-308 (rs1800629); IL6-174 (rs1800795); IL-1&#x3B2;-3954 (rs1143634); IL10-592 (rs1800872); MMP1-1607 (rs1799750) e TLR4-896 (rs4986790); e determinar, nos casos com DTM, a influência dos SNPs candidatos na sensibilidade dolorosa mecânica experimental, na intensidade e no tempo de dor. As frequências genotípicas e de alelos dos sete SNPs candidatos foram comparadas entre 152 indivíduos com DTM e 91 controles, por meio da técnica de PCR em tempo real. A sensibilidade dolorosa mecânica foi avaliada pelo limiar de dor à palpação (LDP) e a intensidade de dor, utilizando-se uma escala analógica visual. As diferenças entre as frequências dos polimorfismos estudados foram avaliadas por meio do teste qui-quadrado (x2) e os valores de LDP entre os grupos foram comparados pelo teste t. A análise de possíveis diferenças entre os subgrupos de genótipos, com relação aos valores de LDP, EAV e tempo de dor, foi feita pelo teste estatístico one-way ANOVA, seguido pelo teste de Tukey. A hipótese nula foi rejeitada, uma vez que houve diferença entre as frequências genotípicas do SNP TNFA-308 entre os grupos, estando o polimorfismo TNFA-308 (1800629) associado às DTMs (p<0,05). Além do TNFA-308, os SNPs COMT Val(158)Met, IL6-174, IL-1&#x3B2;-3954 e TLR4-896 foram capazes de influenciar a sensibilidade dolorosa mecânica em indivíduos doentes (p<0,05). O presente estudo apresenta associação inédita entre o polimorfismo TNFA-308 (1800629) e as DTMs. Encorajamos estudos futuros que elucidem a associação entre genótipos pró-inflamatórios e uma menor sensibilidade dolorosa mecânica.This study aimed at testing the null hypothesis which claims that there is no difference between the group with temporomandibular joint disorder (TMD) and a control group regarding the genotypic and allelic frequencies of the candidate SNPs COMT Val(158)Met (rs4680); TNFA-308 (rs1800629); IL6-174 (rs1800795); IL-1&#x3B2;-3954 (rs1143634); IL10-592 (rs1800872); MMP1-1607 (rs1799750) and TLR4-896 (rs4986790). Additionally, it aimed at determining candidate SNPs influence on experimental mechanical pain sensitivity, intensity and duration of pain in the TMD cases. The genotypic and allelic frequencies of the seven candidate SNPs were compared among 152 individuals from the group with TMD and 91 individuals from the control group, by using the real-time PCR technique. Mechanical pain sensitivity was assessed through pressure pain threshold (PPT) and pain intensity was assessed using visual analogue scales (VAS). Differences between the frequencies regarding the studied polymorphisms were assessed through the chi-square test (x2) while the PPT values were compared through the t-test. Analysis of potential differences between the genotype subgroups with respect to the PPT, VAS and pain duration values was performed with ANOVA one-way test, followed by the Tukeys test. The null hypothesis was rejected, since there were differences among the genotypic frequencies of the TNFA-308 SNP between groups. The TNFA-308 (1800629) polymorphism is found to be associated with the TMDs (p<0.05). In addition to TNFA-308, the SNPs COMT Val(158)Met, IL6-174, IL-1&#x3B2;-3954 and TLR4-896 were capable of influencing mechanical pain sensitivity in individuals with TMD (p<0.05). This study presents an unprecedented association between the TNFA-308 (1800629) polymorphism and TMDs. We encourage future researches that enlighten the association between proinflammatory genotypes and lower mechanical pain sensitivity

Mandibular protraction appliance (MPA) effects in adolescents and adults: a cephalometric comparison

Este estudo retrospectivo teve como objetivo comparar os efeitos esqueléticos, dentários e tegumentares do tratamento com Aparelho de Protração Mandibular (APM) em conjunto com o aparelho fixo em pacientes adolescentes e adultos com má oclusão de Classe II. A amostra foi composta por telerradiografias pré e póstratamento de 23 adolescentes (idade inicial média de 11,75 anos) e de 16 adultos (idade inicial média de 22,41 anos). Testes t (P < 0,05) foram empregados para comparação dos grupos. Os adultos apresentaram menor quantidade de alterações esqueléticas. Com relação às alterações dentárias, os adultos apresentaram menor inclinação lingual dos incisivos superiores; menor extrusão dos incisivos inferiores; menor extrusão dos molares superiores e inferiores; menor mesialização dos molares inferiores; e menor retrusão do lábio superior em comparação aos adolescentes.The aim of this retrospective study was to compare the skeletal, dental, and soft tissue effects of the Mandibular Protraction Appliance (MPA) treatment in adolescent and adult Class II malocclusion patients. The sample comprised pretreatment and posttreatment cephalograms of 23 adolescents (mean pretreatment age 11.75 years) and 16 adults (mean pretreatment age 22.41 years). The groups were compared with t tests, at P < 0.05. The amount of skeletal changes was smaller in the adult group. Adults showed smaller maxillary incisors lingual tipping, mandibular incisor and molar and maxillary molar extrusion and mandibular molar mesialization. Additionally, adults also showed greater upper lip retrusion as compared to adolescents

Effects of mandibular protraction appliance associated to fixed appliance in adults

OBJECTIVE: This retrospective study aimed to conduct a cephalometric evaluation of the skeletal, dental and soft tissue effects resulting from treatment of adult patients presenting Class II malocclusion, performed with a Mandibular Protraction Appliance (MPA) combined with a fixed orthodontic appliance. METHODS: The sample consisted of teleradiographs obtained before and after treatment of 9 adult patients (initial mean age of 22.48 years) with bilateral Class II, division 1, malocclusion. Paired t test (p < 0.05) was applied to compare initial and final values. RESULTS: t test revealed an increase in anteroinferior facial height and posterior facial height. The dental changes include: extrusion of upper incisors, buccal inclination, protrusion of lower incisors, mesialization and extrusion of mandibular molars. Regarding the soft tissue component, there was an increase in nasolabial angle in addition to upper lip retrusion. CONCLUSIONS: The effects of treating Class II malocclusion adult patients, by means of using Mandibular Protraction Appliance (MPA) combined with a fixed appliance were mostly observed in the mandibular arch, and consisted of buccal inclination, protrusion and intrusion of incisors, and mesialization and extrusion of the molars

TMD and chronic pain: A current view

This review aims at presenting a current view on the physiopathologic mechanisms associated with temporomandibular disorders (TMDs). While joint pain is characterized by a well-defined inflammatory process mediated by tumor necrosis factor-&#945; and interleukin, chronic muscle pain presents with enigmatic physiopathologic mechanisms, being considered a functional pain syndrome similar to fibromyalgia, irritable bowel syndrome, interstitial cystitis and chronic fatigue syndrome. Central sensitization is the common factor unifying these conditions, and may be influenced by the autonomic nervous system and genetic polymorphisms. Thus, TMDs symptoms should be understood as a complex response which might get worse or improve depending on an individual's adaptation

Influence of TNF-α-308 G/A gene polymorphism on temporomandibular disorder

Introduction: Tumor necrosis factor alpha (TNF-a) levels are significantly upregulated in the synovial fluid of patients with temporomandibular joint disorder (TMD). The TNF-a influences pain generation and maintenance. Therefore, the aim of this study was to investigate the influence of single nucleotide polymorphism TNFA-308 (rs1800629) on TMD risk and on the pressure pain threshold. Methods: The genotypic and allelic frequencies of candidate single nucleotide polymorphisms were compared among 152 TMD patients and 91 sex- and age-matched healthy subjects in the control group using the real-time polymerase chain reaction technique. The pressure pain threshold in the temporomandibular joint, anterior fascicle of the temporal muscle, masseter muscle, and Achilles tendon were recorded with an algometer. After the pressure test, all participants received a complete physical examination, including masticatory muscle evaluation, temporomandibular joint palpation, and assessment of mandibular range of motion. Results: The TNFA-308 polymorphism is positively associated with TMD. Subjects with TMD had a 2.87 (95% confidence interval, 1.256-6.569) times greater chance of having the GA genotype than did the control group. Rare A-allele homozygotes demonstrated decreased pain sensitivity for the temporomandibular joint and anterior fascicle of the temporal muscle in the pressure pain threshold test compared with ancestral allele homozygotes. Conclusions: This study presents an unprecedented association between the TNFA-308 (rs1800629) polymorphism and TMD. Future studies are needed to enlighten the association between TNFA308 G/A single nucleotide polymorphism and mechanical pain sensitivity. (Am J Orthod Dentofacial Orthop 2016;149:692-8

Maxillary protraction after surgically assisted maxillary expansion

This case report describes the orthodontic treatment of a 32-year-old woman with a Class III malocclusion, whose chief compliant was her dentofacial esthetics. The pretreatment lateral cephalometric tracings showed the presence of a Class III dentoskeletal malocclusion with components of maxillary deficiency. After discussion with the patient, the treatment option included surgically assisted rapid maxillary expansion (SARME) followed by orthopedic protraction (Sky Hook) and Class III elastics. Patient compliance was excellent and satisfactory dentofacial esthetics was achieved after treatment completion