Neurosensory Disturbances After Apical Surgery of Mandibular Premolars and Molars: A Retrospective Analysis and Case-Control Study.

OBJECTIVE Apical surgery is an intervention to treat teeth with persistent or recurrent endodontic infection. The proximity of the mental foramen and mandibular canal may pose a risk of altered sensation when performing surgical interventions in the posterior mandible. The objective of this study was to determine the rate of neurosensory disturbances after apical surgery of mandibular premolars and molars. The secondary objective was to evaluate whether the occurrence of altered sensation correlated with the distances from the apex or the periapical lesion to the relevant anatomical structures. METHODS The charts of patients treated from September 1999 to December 2015 were retrospectively evaluated if an apical surgery had been performed in mandibular premolars or molars, and a minimum period of 1-year follow-up was documented. Patients with trauma or other surgical interventions in the same hemimandible were excluded. Cases with postsurgical altered sensation were defined as the test group. From the pool of unaffected cases, patients were selected to serve as controls. Two- or three-dimensional radiographs of test and control cases were assessed with regard to the shortest distances from the root apices/lesions to the mental foramen or mandibular canal. RESULTS The study population included 243 patients with 249 apical surgeries, of which 12.9% led to postoperative neurosensory disturbances. Sensation returned to normal within 22 days on average. The most frequent findings were hyperesthesia or paresthesia. With regard to the treated type of tooth, second premolars resulted more frequently (22.6%) in altered sensation than the other teeth (11.2 to 13.0%; p=0.310). There were no significant differences when comparing test and control cases regarding the measured distances in radiographs from the apex/lesion to the relevant anatomical structures. CONCLUSION Altered sensation may typically occur following apical surgery in posterior mandibular teeth. However, in all cases of the present study, skin sensitivity in the lip/chin region returned to normal. The clinician must be particularly careful when performing apical surgery of second premolars due to the proximity of the mental foramen

Multiple-crystal X-ray topographic characterization of periodically domain-inverted KTiOPO4 crystal

A periodically domain-inverted KTiOPO4 crystal has been characterized for the first time by multiple-crystal multiple-reflection x-ray topography. The striation contrast within the domain- inverted regions has been revealed in high strain-sensitivity reflection topographs. The origin of formation of the striation contrast and the mechanism of domain inversion in KTiOPO4 are discussed in terms of the structural characteristics of KTiOPO4

Arsenite Methyltransferase Is an Important Mediator of Hematotoxicity Induced by Arsenic in Drinking Water

Chronic arsenic exposures via the consumption of contaminated drinking water are clearly associated with many deleterious health outcomes, including anemia. Following exposure, trivalent inorganic arsenic (AsIII) is methylated through a series of arsenic (+III oxidation state) methyltransferase (As3MT)-dependent reactions, resulting in the production of several intermediates with greater toxicity than the parent inorganic arsenicals. The extent to which inorganic vs. methylated arsenicals contribute to AsIII-induced hematotoxicity remains unknown. In this study, the contribution of As3MT-dependent biotransformation to the development of anemia was evaluated in male As3mt-knockout (KO) and wild-type, C57BL/6J, mice following 60-day drinking water exposures to 1 mg/L (ppm) AsIII. The evaluation of hematological indicators of anemia revealed significant reductions in red blood cell counts, hemoglobin levels, and hematocrit in AsIII-exposed wild-type mice as compared to unexposed controls. No such changes in the blood of As3mt-KO mice were detected. Compared with unexposed controls, the percentages of mature RBCs in the bone marrow and spleen (measured by flow cytometry) were significantly reduced in the bone marrow of AsIII-exposed wild-type, but not As3mt-KO mice. This was accompanied by increased levels of mature RBCS in the spleen and elevated levels of circulating erythropoietin in the serum of AsIII-exposed wild-type, but not As3mt-KO mice. Taken together, the findings from the present study suggest that As3MT-dependent biotransformation has an essential role in mediating the hematotoxicity of AsIII following drinking water exposures

Legacy laser powder bed fusion systems and obsolescence: upgrading control systems

The Additive Manufacturing (AM) market has experienced substantial growth, accompanied by a parallel increase in the number of Laser Powder Bed Fusion (LPBF) systems. This rapid growth has fostered rapid technology advances and with that rapid obsolescence, especially on the digital side of these systems. Thus, industrial LPBF systems are in the risk of being decommissioned solely from effects linked to legacy control systems, limiting their potential utility and integration into modern manufacturing infrastructures. Nevertheless, these legacy systems often possess high-performing specialized hardware, which still retains substantial longevity. To address this challenge, this paper proposes an innovative approach - the development of a unified PBF systems controller as part of the Open Additive Initiative. By updating the control system, this paper suggests the possibility of reintegrating legacy machines into current manufacturing systems, thereby reducing the economic and environmental burdens associated with purchasing new machines

Climate reddening increases the chance of critical transitions

Climate change research often focuses on trends in the mean and variance. However, analyses of palaeoclimatic and contemporary dynamics reveal that climate memory - as measured for instance by temporal autocorrelation - may also change substantially over time. Here, we show that elevated temporal autocorrelation in climatic variables should be expected to increase the chance of critical transitions in climate-sensitive systems with tipping points. We demonstrate that this prediction is consistent with evidence from forests, coral reefs, poverty traps, violent conflict and ice sheet instability. In each example, the duration of anomalous dry or warm events elevates chances of invoking a critical transition. Understanding the effects of climate variability thus requires research not only on variance, but also on climate memory