Optical properties of dental zirconia, bovine dentin, and enamel-dentin structures.

OBJECTIVE: To evaluate the optical properties and the relative translucency parameter of Ceramill ZI White (3Y-TZP) and Ceramill Zolid FX White (5Y-PSZ) zirconia ceramic systems and compare them with those of the bovine dentin and enamel/dentin structures. MATERIALS AND METHODS: 3Y-TZP and 5Y-PSZ zirconia ceramic systems were evaluated. A 0.5-mm-thick 3Y-TZP (3Y-NC.5), 0.5-mm-thick (5Y-NC.5), and 1.4-mm-thick (5Y-C.14) were used. A 0.5-mm-thick dentin specimens and 1.4-mm-thick enamel/dentin specimens (n = 5) were obtained from anterior bovine maxillary teeth. Scattering, absorption, transmittance, and albedo coefficient were calculated using Kubelka-Munk's model. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (p < 0.001), and goodness-of-fit coefficient (GFC). Relative translucency parameter differences were evaluated using translucency thresholds. RESULTS: Reflectance, scattering, absorption, and transmittance properties were wavelength dependent. Good matches (GFC ≥ 0.999) in spectral reflectance were observed between 0.5-mm-thick dentin and 1.4-mm-thick enamel/dentin, and 3Y-NC.5 and 5Y-NC.5. Scattering was the main optical extinction process during light interaction with zirconia and dental structures, as indicated by albedo coefficient. Translucency differences were acceptable only for 3Y-NC.5 and the dentin structure, and 5Y-C.14 and the enamel/dentin structure. CONCLUSIONS: Optical properties of 3Y-TZP and 5Y-PSZ dental zirconia differed from each other and from bovine dental structures. Nevertheless, 3Y-TZP showed similar relative translucency parameter to bovine dentin. CLINICAL SIGNIFICANCE: To achieve the best esthetic results in restorative dentistry, it is crucial for clinicians to know about the optical properties of 3Y-TZP and 5Y-PSZ and to be able to compare these properties with those of dental structures.

Update of the SFMV (French society of vascular medicine) guidelines on the conditions and safety measures necessary for thermal ablation of the saphenous veins and proposals for unresolved issues.

Venous insufficiency is a very common disease affecting about 25% of the French population (if we combine all stages of its progression). It is a complex disease and its aetiology has not yet been fully elucidated. Some of its causes are well known, such as valvular dysfunction, vein wall defect, and the suctioning effect common to all varicose veins. These factors are generally associated and together lead to dysfunction of one or more of the saphenous veins. Saphenous vein dysfunction is revealed by ultrasound scan, a reflux lasting more than 0.5 seconds indicating venous incompetence. The potential consequences of saphenous vein dysfunction over time include: symptoms (heaviness, swellings, restlessness, cramps, itching of the lower limbs), acute complications (superficial venous thrombosis, varicose bleeding), chronic complications (changes in skin texture and colour, stasis dermatitis, eczema, vein atresia, leg ulcer), and appearance of unaesthetic varicose veins. It is not possible to repair an incompetent saphenous vein. The only therapeutic options at present are ultrasound-guided foam sclerotherapy, physical removal of the vein (saphenous stripping), or its thermal ablation (by laser or radiofrequency treatment), the latter strategy having now become the gold standard as recommended by international guidelines. Recommendations concerning thermal ablation of saphenous veins were published in 2014 by the Société française de médecine vasculaire. Our society has now decided to update these recommendations, taking this opportunity to discuss unresolved issues and issues not addressed in the original guidelines. Thermal ablation of an incompetent saphenous vein consists in destroying this by means of a heating element introduced via ultrasound-guided venous puncture. The heating element comprises either a laser fibre or a radiofrequency catheter. The practitioner must provide the patient with full information about the procedure and obtain his/her consent prior to its implementation. The checklist concerning the interventional procedure issued by the HAS should be validated for each patient (see the appended document).

[French Society of Vascular Medicine good medical practice guidelines on safety and environment in vascular medicine: Treatment of varicose veins]. / Recommandations de bonne pratique concernant la sécurité et l'environnement en médecine vasculaire, notamment pour le traitement des varices, proposées par la Société française de médecine vasculaire.

These guidelines proposed by the French Society of Vascular Medicine define the optimal environment for vascular medicine practice: outpatient clinic; equipment, layout and maintenance of the care center; infection risk prevention (hand hygiene, individual protective measures, exposure to blood, ultrasound apparatus, etc.); common interventions and techniques (liquid and foam sclerotherapy, endovenous thermal treatments). These guidelines do not include phlebectomy and use of ultrasound contrast agents.

Impact of anatomical location of lower limb venous thrombus on the risk of subsequent cancer.

After a proximal deep-vein thrombosis (P-DVT), the risk of diagnosis of a previously unsuspected cancer is high. Isolated distal DVT (iD-DVT; i.e. infra-popliteal DVT without pulmonary embolism [PE]) and isolated superficial-vein thrombosis (iSVT; i.e. without concomitant DVT and PE) are at least as frequent as P-DVT but their association with subsequent cancer is uncertain. We exploited data from the OPTIMEV prospective, observational, multicentre study to i) compare the risk of subsequent cancer three years after a first objectively confirmed iSVT, iD-DVT and iP-DVT in patients without a prior history of cancer or of venous thromboembolism, ii) assess predictors of subsequent cancer in cases of iD-DVT. The overall cumulative rates of cancer among the 304 patients with iSVT, 536 patients with iD-DVT, and 327 patients with iP-DVT were similar (3.4% 95% confidence interval [1.8-6.2], 3.9% [2.5-5.9] and 3.9% [2.3-6.8], respectively), regardless of whether the index venous thromboembolic event was unprovoked or associated with a major transient risk factor. Neither anatomical (muscular vs deep-calf DVT) nor ultrasound scan characteristics (number of thrombosed veins, clot diameter under compression) seemed strongly associated with the risk of cancer in cases of iD-DVT. In patients managed in routine practice, all the different clinical expressions of lower limb venous thromboembolism are associated with a similar risk of subsequent cancer. From a clinical practice point of view, this suggests that cancer screening, without discussing the necessity, or not, of such screening, should not differ between a deep-proximal, deep-distal or superficial location of thrombosis.