ABSTRACT
Current technologies of plasma electrolytic oxidation (PEO) for modifying the surfaces of dental implants made of the Grade IV titan alloy provide predictable long-term results in implant dentistry. The aim of the study is to evaluate the efficacy of PEO technology comparing two types of surface modification of dental implants made of VT1-0 medical titanium alloy. Materials and Methods: 50 IRIS dental implants (Scientific Production Company LICOSTOM, Russia), 10-mm long and 4 mm in diameter, were manufactured from the VT1-0 alloy. The implant surface was treated by two PEO methods: 1) in the aqueous solution of alkaline electrolyte without any additional modifiers (PEO-Ti); 2) in the aqueous solution of orthophosphoric acid-based electrolyte containing calcium carbonate (PEO-Ca). Implants made of VT1-0 alloy after milling and without additional treatment served as control samples. The implant surfaces were studied by electron microscopy and energy dispersive X-ray spectrometry. Some of the implants were installed in sheep, samples were obtained at 2, 4, and 8 weeks and studied by microcomputer tomography. Results: Regardless of the electrolyte composition, a highly developed porous surface was formed in the samples with PEO-modified surfaces. The surface of the PEO-Ti samples in a simple unmodified electrolyte was characterized by a large number of open pores with a wide range of size distribution from 200 nm to 3 µm. The pore size distribution was of a monomodal character, with a maximum near 0.23 µm. The PEO samples in the Ca-containing electrolyte had pores also in a wide range from ~80 nm to ~7 µm. The pore distribution, in contrast to PEO-Ti, was bimodal in nature, with the main maximum in the region of 1.05 µm and the concomitant maximum near 2.45 µm.The obtained surfaces of both types (PEO with Ca and Ti) possessed high purity and optimal microroughness for osseointegration. Both types of PEO treatment (PEO with Ca and Ti) have demonstrated a similar osseointegrative potential, nevertheless, the surface of the PEO-Ca showed a better contact with the implant surface (49.8%) than PEO-Ti (42.4%) obviously due to the presence of calcium in its composition. Conclusion: The PEO-formed implant surfaces demonstrate high osseointegrative properties after any variants of treatment and show the potential for application in osteoporosis.
Subject(s)
Dental Implants , Animals , Sheep , Alloys , Calcium Carbonate , Calcium, Dietary , ElectrolytesABSTRACT
Surgical brain revascularization is an important treatment for acute or chronic ischemia, intracranial aneurysms and skull base tumors. Individual anatomy of brain vessels should be clearly understood for this procedure. Variants of collateral cerebral blood flow in patients with cerebrovascular diseases depend on individual characteristics of circle of Willis and reserve mechanisms of collateral circulation. These anatomical variations require careful preoperative planning to choose the optimal revascularization option.
Subject(s)
Cerebral Revascularization , Cerebrovascular Disorders , Intracranial Aneurysm , Cerebrovascular Circulation , Humans , Intracranial Aneurysm/diagnostic imaging , Intracranial Aneurysm/surgery , Neurosurgical ProceduresABSTRACT
This review is devoted to various techniques for reduction of brain damage during retraction. Searching for reports was carried out in Russian and English languages using the PubMed database (n=721) without restrictions on language, date and study design according to the following keywords: «brain retraction injury¼, «spatula brain retractors¼, «tubular brain retractors¼, «retractorless neurosurgery¼. Primary screening and exclusion of duplicate manuscripts allowed us to single out the main group of articles (n=121). Some reports were excluded due to non-compliance with inclusion criteria (no description of methods, few references and insufficient data). The final list included 32 studies which were represented by cohort studies, retrospective analyses of surgical interventions, as well as experimental and laboratory studies. Small number of publications did not allow us to obtain unambiguous conclusions. Further research is required to reduce brain retraction trauma.
Subject(s)
Brain Injuries , Neurosurgical Procedures , Brain/diagnostic imaging , Brain/surgery , Humans , Retrospective Studies , Surgical InstrumentsABSTRACT
Carpal tunnel syndrome (CTS) requires special attention due to its different reasons and course. Knowledge about the variability of median nerve (MN) topography in carpal canal region, features of diagnosis and treatment extends outlooks on this pathology. Aggregating rare clinical cases from the Medline and Pubmed databases is useful to form personified approach. There are 3 types of topographic variations which should be considered to prevent false-positive diagnosis of pathology: recurrent branch location, early bi- and trifurcations of MN, anastomoses. Since acute CTS is treated only by surgery, every surgical approach is aimed at minimally invasiveness and fast recovery. Endoscopic decompression (ED) is more favorable regarding these aspects. However, this method cannot be considered as perfect due to available data about incomplete decompression and certain incidence of recurrences. The last ones are absent after microsurgical decompression as a rule. It can be concluded that only individual approach is advisable for complete release of CTS without iatrogenic damage and recurrences.