The aim of our study was to evaluate the correlations between mandibular third molar impaction status and mandibular angle and condylar fractures.Materials and Methods: This retrospective cross-sectional study included patients with unilateral and isolated angle or condylar fractures. Patient records and panoramic radiographs were evaluated. The predictor variables included the presence, impaction status (Pell and Gregory [P&G] classification), and angulation (Winter classification) of the third molar. The outcome variable was the type of fracture, whereas other predictor variables included demographic factors such as age, gender, and fracture etiology. Bivariate (c 2 test) and logistic regression analyses were conducted to estimate the associations between variables and the outcome.Results: The sample was composed of 164 angle fracture (mean age, 31.6 AE 12.3 years; 83.5% male) and 115 condylar fracture (mean age, 41.9 AE 16.8 years; 76.5% male) patients. A third molar was present in 72.6% of the angle fracture group and 54.8% of the condylar fracture group (P = .002). Deep impactions (classes IC, IIC, IIIB, and IIIC) exhibited an odds ratio (OR) of 3.60 for angle fractures (P < .001). No association was found between tooth angulations and the type of fracture. According to logistic regression analysis, older age (adjusted OR, 1.05; 95% confidence interval [CI], 1.03 to 1.07), P&G class I impaction (OR, 1.86; 95% CI, 1.09 to 3.20), and P&G class A impaction (OR, 1.91; 95% CI, 1.12 to 3.24) were significantly associated with condylar fractures whereas the presence of a third molar (OR, 0.46; 95% CI, 0.28 to 0.76) or P&G class B impaction (OR, 0.287; 95% CI, 0.12 to 0.69) was associated with angular fractures.Conclusions: P&G class II or III and class B impaction status was significantly associated with angle fractures, whereas missing or fully erupted (class IA) third molars significantly correlated with condylar fractures.
There is no consensus about the most suitable in vitro simulating material investigating heat generation during bone preparation. The aim was to compare heat increases and drilling times of bone removals in different bone simulating materials and to compare them to fresh human cadaver bone. A cavity was drilled in the following samples: (1) bovine rib; (2) pig rib; (3) 20 PCF (lb/ft 3 ) polyurethane (PU) block with 3 mm (50 PCF) cortical layer; (4) 20PCF PU without cortical; (5) 30 PCF PU with 2 mm (40 PCF) cortical; (6) 30 PCF PU with 1 mm (40 PCF) cortical; (7) 30PCF PU without cortical; (8) poly-methyl-methacrylate (PMMA); (9) fresh human cadaver rib. Data were analyzed with ANOVA followed by Tukey’s post hoc tests. P < 0.05 was considered significant. Highest heat increases and slowest drilling times were found in bovine ribs (p < 0.001). Regarding temperatures, human ribs were comparable to the pig rib and to PUs having cortical layers. Considering drilling times, the human rib was only comparable to the 20 PCF PU with 3 mm cortical and to 30 PCF PU without cortical. By the tested in vitro bone removals, only the 20 PCF PU with 3 mm cortical was able to simulate human ribs, considering both temperature increases and drilling times.
<p>The Pannonian Basin is a continental extensional basin system with various depocentres within the Alpine&#8211;Carpathian&#8211;Dinaridic orogenic belt. Along the western basin margin, exhumation along the Rechnitz, Pohorje, Kozjak, and Baj&#225;n detachments resulted in the cooling of variable units of the Alpine nappe stack. This process is constrained by thermochronological data between ~25&#8211;23 to ~15 Ma (Fodor et al., 2021). Rapid subsidence in supradetachment sub-basins indicates the onset of sedimentation in the late Early Miocene from ~19 or 17.2 Ma. In addition to extensional structures, strike-slip faults mostly accommodated differential extension; branches of the Mid-Hungarian Shear Zone (MHZ) could also play the role of transfer faults.</p> <p>During this period, the hanging wall margin of the detachment system, i.e., the pre-Miocene rocks of the Transdanubian Range (TR) experienced surface exposure, karstification, and terrestrial sedimentation. After ~14.5 Ma faulting, subsidence, and basin formation shifted north-eastward and reached the TR where fault-controlled basin subsidence lasted until ~8 Ma.</p> <p>3D thermo-mechanical forward models analyze this depocenter migration and predict the subsidence and heat flow evolution that fits observational data. These models consider fast lithospheric thinning, mantle melting, lower crustal viscous flow, and upper crustal brittle deformation. Models suggest ~150&#8211;200 km of shift in depocenters during ~12 Myr.</p> <p>Simultaneously with depocenter migration, the southern part of the former rift system, near or within the MHZ, underwent ~N&#8211;S shortening; the early syn-rift basin fill was folded and their boundary faults were inverted. Deformation was dated to ~15&#8211;14 Ma (&#8222;middle&#8221; Badenian) and continued locally to ~9.7 Ma while north of the MHZ the TR was still affected by modest extensional faulting. The particularity of this shortening is that it happened during the post-rift thermal cooling stage. The low-rate contraction and related uplift rarely exceeded this regional thermal subsidence.</p> <p>MOL Ltd. largely supported the research. The research is supported by the scientific grant NKFI OTKA 134873 and the Slovenian Research Agency (No. P1-0195).</p> <p>Fodor, L., Bal&#225;zs, A., Csillag, G., Dunkl, I., H&#233;ja, G., Jelen, B., Kelemen, P., K&#246;v&#233;r, Sz., N&#233;meth, A., Ny&#237;ri, D., Selmeczi, I., Trajanova, M., Vrabec, M., Vrabec, M. (2021): Crustal exhumation and depocenter migration from the Alpine orogenic margin towards the Pannonian extensional back-arc basin controlled by inheritence. Global and Planetary Change 201, 103475. 31p. https://doi.org/10.1016/j.gloplacha.2021.103475</p>
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