Clinical analysis of 60 cases with radiative nasopharyngeal necrosis in nasopharyngeal carcinoma / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study the clinical characteristics, diagnosis, treatment and prognostic factors of patients with postradiation nasopharyngeal necrosis (PRNN) in nasopharyngeal carcinoma (NPC).</p><p><b>METHODS</b>Sixty patients with PRNN were studied retrospectively, 50 males and 10 females, age ranging from 30 - 70 years of (median 51.5 years). All patients were treated with endoscopic debridement and systemic or local anti-inflammatory treatment. Kruskal-Wallis H test was used to assess the interval time between irradiation completion and necrosis onset and related factors of treatment outcome. Multivariate Cox proportional hazards regression survival analysis was performed to analyze risk factors.</p><p><b>RESULTS</b>The latent period between the last irradiation and the onset of the symptom ranged from 1 to 156 months, with a median of 5 months. The median interval time was 7.0 months in 1 course group and 4.5 months in ≥2 courses group (χ2=5.527, P=0.031), and 7.5 months in T2 group and 5.0 months in ≥T3 group (χ2=4.330, P=0.037), respectively. Forty-one patients of them had nasopharyngeal infection, and the difference in curative effect between infection group and non-infection group was significantly (χ2=14.775, P<0.001). Symptoms were alleviated in all patients after endoscopic debridement and systemic or local anti-inflammatory treatment. Follow-up for all patients ranged from 2 to 46 months (median 12.5 months). Seven patients with internal carotid artery exposure died of sudden nasopharyngeal massive bleeding and fifteen patients died of tumor or systemic exhaustion; five cases were lost, and the rest were all in survival. Inter carotid artery erosion was an independent prognostic risk factor according to multivariate Cox proportional hazards regression survival analysis (P<0.05).</p><p><b>CONCLUSIONS</b>Endoscopic debridement is effective in treating irradiation-related nasopharyngeal necrosis. The occurrence of nasopharyngeal necrosis is related to infection, irradiation dose and course, and T stage. Internal carotid artery erosion is a severe situation and also an independent prognostic factor for the patients. The most common causes of death were nasopharyngeal bleeding and systemic exhaustion.</p>

[An investigation on dental bio-tribological characteristics of prosthesis made of titanium material].

OBJECTIVE: This study aimed at investigating bio-tribological property of titanium opposite to teeth as a base of clinical application. METHODS: Under a modified fretting machine, wear tests on human natural teeth were carried out in artificial saliva conditions against to pure titanium. The dynamic frictional process and wear mechanisms were investigated by means of Nene-2, MVK-H12, TALYSURF6, OM, LSM, SEM, EDX. RESULTS: The coefficient of friction exhibited a variation pattern of longs. The wear mechanism of natural tooth was detected as micro-cut and denaturation of dental texture and the wear depth of Ti/teeth was 20.33 + 2.86 microm, the wear depth of Ti/Ti being 38.00 + 5.88 microm (P < 0.05). CONCLUSIONS: The natural tooth has a good tribological behavior, matching the friction behavior of pure titanium. Over occlusal force during masticate process and para-function should be avoided. When we chose dental materials, wear resistance should be taken into account.