Prevalence of sagittal molar and canine relationships, asymmetries and midline shift in relation to temporomandibular disorders (TMD) in a Finnish adult population

Abstract Objective: To examine the prevalence of sagittal relationships, asymmetries and midline shift, and their associations with temporomandibular disorders (TMD) in the Northern Finland Birth Cohort 1966 (NFBC1966). Materials and methods: 1845 subjects participated in a clinical examination at the age of 46. Occlusal measurements were performed using 3D models. Symptoms of TMD were screened using validated questions, and signs and diagnoses of TMD were assessed using a modified protocol of the Diagnostic Criteria for TMD (DC/TMD) and questionnaires. Associations between variables of occlusion and TMD were evaluated with χ²-test and Fisher’s exact test and using logistic regression analyses, adjusted for self-reported general health, mental health, bruxism, and rheumatoid arthritis. Results: The most common sagittal relationships were Class I and normal canine relationship. Half-cusp Class II and post-normal canine relationship were more frequent in females, and Class III and pre-normal canine relationship in males. Deviations from normal cuspid or molar relationships showed a weak but statistically significant association with TMD, especially in females. Half-cusp Class II and Class II relationships were more frequent in relation to joint-related TMD signs and diagnoses while missing canines were associated with pain-related TMD diagnoses. Conclusions: The present study findings gave some indications that canine relationships are associated with pain-related TMD, whereas Angle II sagittal occlusal relations may associate with joint-related TMD. Occlusal characteristics should therefore be taken into account as one possible associating factor in subjects with TMD

Neoarchean-mesoproterozoic mafic dyke swarms of the indian shield mapped using google earth™ images and arcgis™, and links with large igneous provinces

We present dyke swarm maps generated using Google Earth™ images, ArcGIS™, field data, and available geochronological ages of Neoarchean-Mesoproterozoic (ranging in age from ~2.80 to ~1.10Â Ga) mafic dyke swarms and associated magmatic units of the different Archean cratons of the Indian shield which represent the plumbing system of Large Igneous Provinces (LIPs). The spatial and temporal distributions together with the trends of the dyke swarms provide important informations about geodynamics. Twenty four dyke swarms (17 have been precisely dated), mostly mafic in nature, have been mapped from the different cratons and named/re-named to best reflect their location, trend, distribution and distinction from other swarms. We have identified 14 distinct magmatic events during the Neoarchean-Mesoproterozoic in the Indian shield. These intraplate magmatic events (many of LIP scale) of the Indian shield and their matches with coeval LIPs on other crustal blocks suggest connections of the Indian shield within known supercontinents, such as Kenorland/Superia (~2.75–2.07Â Ga), Columbia/Nuna (1.90–1.38Â Ga), and Rodinia (1.20–0.72Â Ga). However, further detailed U–Pb geochronology and associated paleomagnetism are required to come to any definite constraints on the position of the Indian cratons within these supercontinents

The Mantle Section of Neoproterozoic Ophiolites from the Pan-African Belt, Eastern Desert, Egypt: Tectonomagmatic Evolution, Metamorphism, and Mineralization

The Eastern Desert (ED) Neoproterozoic ophiolites are tectonically important elements of the Arabian–Nubian Shield. Although affected by various degrees of dismemberment, metamorphism, and alteration, almost all of the diagnostic Penrose-type ophiolite components can be found, namely, lower units of serpentinized peridotite tectonite and cumulate ultramafics and upper units of layered and isotropic gabbros, plagiogranites, sheeted dykes and pillow lavas. The contacts between the lower unit (mantle section) and the upper unit (crustal section) were originally magmatic, but in all cases are now disrupted by tectonism. The mantle sections of the ED ophiolites are exposed as folded thrust sheets bearing important and distinctive lithologies of serpentinized peridotites of harzburgite and dunite protoliths with occasional podiform chromitites. The ED ophiolites show a spatial and temporal association with suture zones that indicate fossil subduction zone locations. Multiple episodes of regional metamorphism mostly reached greenschist facies with less common amphibolite facies localities. CO₂-metasomatism resulted in the development of talc–carbonate, listvenite, magnesite, and other carbonate-bearing meta-ultramafic rocks. Geochemical data from the ED serpentinites, despite some confounding effects of hydration and alteration, resemble modern oceanic peridotites. The ED serpentinites show high LOI (≤20 wt%); Mg# mostly higher than 0.89; enrichment of Ni, Cr, and Co; depletion of Al₂O₃ and CaO; and nearly flat, depleted, and unfractionated chondrite-normalized REE patterns. The modal abundance of clinopyroxene is very low if it is present at all. Chromian spinel survived metamorphism and is widely used as the most reliable petrogenetic and geotectonic indicator in the ED ophiolite mantle sections. The high-Cr# (mostly ~0.7) and low-TiO₂ (mostly ≤ 0.1 wt%) characters of chromian spinel indicate a high degree of partial melt extraction (≥30%), which is commonly associated with fore-arc settings and equilibration with boninite-like or high-Mg tholeiite melts. Based on the general petrological characteristics, the ED ophiolitic chromitites are largely similar to Phanerozoic examples that have been attributed to melt–peridotite interaction and subsequent melt mixing in fore-arc settings. The comparison between the ED Neoproterozoic mantle peridotites and Phanerozoic equivalents indicates considerable similarity in tectonomagmatic processes and does not support any major changes in the geothermal regime of subduction zones on Earth since the Neoproterozoic era. The mantle sections of ED ophiolites are worthy targets for mining and exploration, hosting a variety of ores (chromite, gold, and iron/nickel laterites) and industrial minerals (talc, asbestos, and serpentine)