DNA is hypomethylated in circadian manifestations of bruxism.

OBJECTIVE: The aim of this study was to compare the global DNA methylation levels in patients under bruxism treatment and a control group. METHODS: Subjects undergoing bruxism treatment were classified in awake bruxism (42 patients), sleep bruxism (32 patients) and both conditions (42 patients). The control group included 42 individuals. A colorimetric assay (MethylFlash Methylated DNA 5-mC Quantification Kit, Epigenetic Group Inc., NY, USA) was used to determine the global DNA methylation levels. RESULTS: Statistically significant differences were found in amounts of methylated DNA in all circadian manifestations of bruxism compared with a control group (sleep bruxism = 0.95% ± 2.02%; awake bruxism = 0.87% ± 2.1%; sleep and awake bruxism = 0.17% ± 0.25%; Control = 1.69% ± 1.6%; Kruskal-Wallis test [p = .0001] followed by Dunn's test [p < .05]). CONCLUSION: Patients undergoing bruxism treatment exhibited hypomethylated DNA levels when compared to control group. Our results suggest that DNA hypomethylation might be a novel aetiologic factor in bruxism aetiology. Further researches must be performed exploring the role of epigenetics modifications in circadian manifestations of bruxism.

Genetic polymorphisms in the serotonergic system are associated with circadian manifestations of bruxism.

Bruxism (BRX) is a condition of great interest for researchers and clinicians in dental and medical areas. BRX has two circadian manifestations; it can occur during sleep (sleep bruxism, SB) or during wakefulness (awake bruxism, WB). However, it can be suffered together. Recent investigations suggest that central nervous system neurotransmitters and their genes could be involved in the genesis of BRX. Serotonin is responsible for the circadian rhythm, maintaining arousal, regulating stress response, muscle tone and breathing. Thus, serotonin could be associated with BRX pathogenesis. The aim of this work was to evaluate the frequency of genetic polymorphisms in the genes HTR1A (rs6295), HTR2A (rs1923884, rs4941573, rs6313, rs2770304), HTR2C (rs17260565) and SLC6A4 (rs63749047) in subjects undergoing BRX treatment. Patients included were classified according to their diagnosis in awake bruxism (61 patients), sleep bruxism (26 patients) and both (43 patients). The control group included 59 healthy patients with no signs of BRX. Data showed significant differences in allelic frequencies for the HTR2A rs2770304 polymorphism, where the C allele was associated with increased risk of SB (odds ratio = 2·13, 95% confidence interval: 1·08-4·21, P = 0·03). Our results suggest that polymorphisms in serotonergic pathways are involved in sleep bruxism. Further research is needed to clarify and increase the current understanding of BRX physiopathology.

Dolor miofascial en el territorio craneocervical: Una revisión de la patología y su relación con polimorfismos genéticos del sistema GABAérgico / Myofascial Pain in the craneocervical territory: A review of the pathology and its relationship with the GABAergic system genetic polymorphisms

El dolor miofascial es una patología muscular regional no inflamatoria caracterizada por la presencia de una zona hiperirritable de tejido muscular que se encuentra en una banda tensa, denominado punto gatillo. En la región orofacial pertenece a un conglomerado de patologías denominadas trastornos temporomandibulares, correspondiendo al de mayor prevalencia. Las manifestaciones clínicas van desde dolor local, tensión muscular y disfunción estructural hasta dolor referido, fenómenos autonómicos e hiperexcitabilidad en el sistema nervioso central. Durante las últimas décadas se han asociado variantes genéticas con diferentes expresiones en patologías dolorosas, algunas de las cuales se encuentran en el sistema GABAérgico. En el presente artículo se realiza una revisión del dolor miofascial como patología y su relación con estos polimorfismos genéticos (AU)

Myofascial pain is noninflammatory regional muscular disorder characterized by the presence of a muscle tissue area hyperirritable located on a taut band, called trigger point. In the orofacial region myofascial pain belongs to a cluster of diseases called temporomandibular disorder. Within these pathologies, it is to the most prevalent of its, clinical manifestations include local pain, muscle tension, structural dysfunction, referred pain, autonomic phenomena and hyperexcitability in the central nervous system. During the last decades have been associated genetic variants to painful pathologies, some of which are in the GABAergic system. This article performs a review of myofascial pain as pathology and its relation to genetic polymorphisms in GABAergic system (AU)

Clinical, imaging and genetic analysis of double bilateral radix entomolaris.

BACKGROUND: Anatomy describes that first mandibular molars have two roots: 1 mesial, with 2 root canals, and 1 distal, with 1 root canal. The presence of three roots in these teeth is uncommon. Root anatomical variations have an impact, especially in endodontic, where the highest rates of nonsurgical treatment failures are due to the inability to identify and access roots and/or accessory canals. The aim of this research is to report a case of double three-rooted mandibular first molar through clinical, imaging and genetic analysis. MATERIALS AND METHODS: Using a panoramic radiography, the presence of three roots in teeth 36 and 46 was diagnosed in a female patient. Additionally, it was indicated a cone beam computed tomography. Moreover, leukocyte genomic DNA was obtained from a blood sample of the patient to determine her ethnicity through analysis of mitochondrial DNA haplogroups using polymerase chain reaction-length restriction fragment polymorphism (PCR-RFLP). RESULTS: Both molars had three roots, 1 mesial (M), 1 distolingual (DL), also known as radix entomolaris (RE), and a distovestibular (DV). For both teeth, M root had 2 canals, and DV and DL roots presented just 1 canal. Mitochondrial DNA analysis determined presence of haplogroup C, corresponding to Amerindian ethnicity. CONCLUSIONS: The presence of RE is uncommon. This case report contributes to describe this rare anatomical variation. To our knowledge, this is the first molecular-genetic study applied to dental anatomy and gives basis to develop future research in the area.

Reliability of two techniques for measuring condylar asymmetry with X-rays / Confiabilidad de dos técnicas de medición de asimetría condilar con método radiográfico

Among structural alterations that can be a risk factor for temporomandibular joint disorder (TMD) is condylar asymmetry. In order to measure the condylar asymmetry index in panoramic x-rays quantitatively, two methods have been proposed: those of Habets and Kjellberg. The aim of this study was to determine whether the x-ray method of measuring condylar asymmetries in orthopantomographies presents a minor tendency to error due to slight displacements of the head in the horizontal plane. 30 patients between 18 and 25 years of age were assessed. Each of them underwent three panoramic x-rays in three different positions: orthoradial, and at 5 and 10 horizontal angles. Then the Habets and Kjellberg measurements were taken. Habets' technique did not show any statistically significant differences in the x-rays at 5° and 10° horizontal angles compared to the 0 angle. However, Kjellberg's technique showed statistically significant differences only at the 10° angle compared to the 0 angle. The 10° changes produced linear and ratio variations, but the indices did not vary. It was concluded that both methods provide acceptable clinical information within the limitations of these techniques to obtain data on condylar symmetries or asymmetries of the mandibular body or ramus.

Dentro de las alteraciones estructurales que pueden ser un factor de riesgo de desarrollo de un trastorno temporomandibular (TTM) se menciona a la asimetría condilar. Para realizar la medición cuantitativa del índice de asimetría condilar en radiografías panorámicas se han propuesto dos métodos, Habets y Kjellberg. El objetivo de este estudio fue determinar si el método radiográfico de medición de asimetrías condilares en ortopantomografías que presenta menor tendencia al error por leves desplazamientos de la cabeza en el plano horizontal. Se evaluaron 30 pacientes entre 18 y 25 años de edad. Cada uno de ellos se sometió a tres radiografías panorámicas en tres posiciones distintas: posición ortoradia, 5 y 10 de angulación horizontal. Posteriormente, se realizaron las mediciones de Habets y Kjellberg. La técnica de Habets no mostró diferencias estadísticamente significativas en las radiografías con 5° y 10° de angulación horizontal con respecto al ángulo de 0. Sin embargo, la técnica de Kjellberg mostró diferencias estadísticamente significativas sólo al ángulo de 10° con respecto al ángulo de 0. Las alteraciones de 10° produjeron variaciones lineales y de razones, sin embargo no variaron los índices. Se concluye que ambos métodos entregan información clínica aceptable con las limitaciones que estas técnicas tienen para obtener información sobre simetrías o asimetrías condilares de cuerpo o de rama.