Micro computed tomography (µCT) follows the same principle of computed-tomography used for patients, however providing higher-resolution. Using a non-destructive approach, samples can be scanned, and each section obtained is used to build a volume using tridimensional reconstruction. For bone analysis, it is possible to obtain information about the tissue's microarchitecture and composition. According to the characteristics of the bone sample (e.g. human or animal origin, long or irregular shape, epiphysis or diaphysis region) the pre-scanning parameters must be defined. The resolution (i.e. voxel size) should be chosen taking into account the features that will be evaluated, and the necessity to identify inner structures (e.g. bone channels and osteocyte lacunae). The region of interest should be delimited, and the threshold that defines the bone tissue set in order to proceed with binarization to separate the voxels representing bone from the other structures (channels, resorption areas, and medullary space). Cancellous bone is evaluated by means of the trabeculae characteristics and their connectivity. The cortex is evaluated in relation to the thickness and porosity. Bone mineral density can also be measured, by the amount of hydroxyapatite. Other parameters such as structure-model-index, anisotropy, and fractal dimension can be assessed. In conclusion, intrinsic and extrinsic determinants of bone quality can be assessed by µCT. In dentistry, this method can be used for evaluating bone loss, alterations in bone metabolism, or the effects of using drugs that impair bone remodeling, and also to assess the success rate of bone repair or surgical procedures.

BackgroundTo review and discuss important topics regarding periodontal treatment pre- and post-radiotherapy for head and neck cancer in human patients; to discuss the references for adequate techniques, the appropriate moment for tooth extractions and periodontal management; and to discuss the prevention of osteoradionecrosis.Material and MethodsThirty-nine studies including original studies, randomized clinical trials (RCTs) and reviews were searched in online databases MEDLINE (PubMed) and the Cochrane library. No year of publication restriction was applied.ResultsLanguage was restricted to English, and the following Medical Subject Heading terms were used: radiotherapy, radiation therapy and periodontal treatment. Studies regarding periodontal treatment and tooth extraction that involved clinical management of irradiated patients were selected.ConclusionsThe treatment of periodontal diseases before radiotherapy is mainly required to avoid future dental extraction and to reduce the development of osteoradionecrosis. Periodontal treatment in irradiated patients mostly includes scaling and root planing, extraction of condemned teeth and topical and systemic antimicrobial therapy. Tooth removal should be planned at least 14 days before the first day of radiation treatment. Particular care and mouthwashes should be taken during and after radiation.Clinical SignificanceThe management of irradiated patients represents a challenge for health professionals, including dentists. It is important to establish recommendations for clinicians concerning dental and periodontal management in irradiated patients before, during and after treatment. Key words:Head and neck cancer, radiotherapy, periodontal treatment, periodontitis.

No abstract

The aim of this scoping review was to provide sufficient information about the effectiveness of ozone gas in virus inactivation of surfaces and objects under different environmental conditions. The review was performed according to the list of PRISMA SrC recommendations and the JBI Manual for Evidence Synthesis for Scoping Reviews. The review was registered in Open Science Framework (OSF). EMBASE (Ovid), Lilacs, LIVIVO, MEDLINE (PubMed), SciELO, Scopus and Web of Science were primary sources, and "gray literature" was searched in OpenGray and OpenThesis. A study was included if it reported primary data on the effect of ozone gas application for vehicle-borne and airborne virus inactivation. No language or publication date restriction was applied. The search was conduct on July 1, 2020. A total of 16,120 studies were screened, and after exclusion of noneligible studies, fifteen studies fulfilled all selection criteria. Application of ozone gas varied in terms of concentration, ozone exposure period and the devices used to generate ozone gas. Twelve studies showed positive results for inactivation of different virus types, including bacteriophages, SARS-CoV-2 surrogates and other vehicleborne viruses. Most of the studies were classified as unclear regarding sponsorship status. Although most of the population has not yet been vaccinated against COVID-19, disinfection of environments, surfaces, and objects is an essential prevention strategy to control the spread of this disease. The results of this Scoping Review demonstrate that ozone gas is promising for viral disinfection of surfaces.

No abstract