احمد نظير جبر الزيدي

ABSTRACT: Background: radiotherapy for the treatment of head and neckcancer can produce damage to tissue and specifically salivary glands, causing an alteration in composition of saliva accompanied with oral mucositis. The present study was designed to investigate the changes in saliva components before and after irradiation in comparison to control. Methods: Sixty human male participate in this study. Thirty of them were patients with head and neck cancer prior to and after radiotherapy were evaluated for constituents of saliva and compared with other thirty free of cancer as a control group. Collection of 2ml of stimulated saliva with biochemical analysis of (buffering capacity, salivary amylase and salivary total protein) were done for all subjects. Results: the current findings show an increment in salivary flow rate for irradiate patients compared to control. while reduction in buffer capacity was observed in irradiate patient in comparison to control. Results for both salivary amylase and salivary total protein illustrated a reduction in their concentration before and after irradiation in comparison to control with significant difference value. Conclusion: Radiotherapy affects salivary glands causing alteration in biochemical components of saliva and may cause oral tissue damage.

Abstract Objectives: the purpose of this research is to investigate and collect data about the most commonly used impression disinfection protocol by the dental students, general practices and specialists of Iraqi dentists. Materials and Method: The study was conducted as a descriptive survey of infection control measures in the dental students, general practices and specialists of Iraqi dentists. A self-administered questionnaire was designed to assess the knowledge, attitude, and practices of infection control measures by dentists. The questionnaire was pretested, revised, and retested before use. The study population included dental students, general practices and specialists of Iraqi dentists in August 2020 (n=309) to whom the questionnaires were distributed. Three researchers gathered questionnaire data by google drive questionnaire because of COVID-19 pandemic. No tracking system was used to determine who responded to ensure anonymity. Institutional ethical committee approval was obtained before administration of the questionnaire. Results: Out of the 309 participants to whom the questionnaire was sent by email, all of them are responding to the questionnaire, about 87.4% using disinfectants while 12.6% of the participant has no belief in disinfection of dental impression, while 70.9% of the participants rinsing dental impression with water and 29.1% did not rinse the impression. Conclusion: 1-Impression disinfection is an important part of cross infection control to reduce infection spread between patient, dentist and technician. 2-Choice of type of disinfectant material and method depend on the dentist's preference, available equipment, material availability and cost. 3-It is important to ensure that the chosen disinfectant material causes no deterioration and dimensional change to the impression material used.

The results of surface roughness indicated increase of roughness values with increased polyester fibers concentration in A-2186 silicone elastomer when compared with non-reinforced silicone. For instance, it has been evaluated that the fine random dispersion of Carbone nanotubes in PDMS, forming PDMS/CNT composites lead to increase the surface roughness [17]. The increase in surface hardness was directly proportional to the increase of polyester fibers concentration. This could be due to dispersing of polyester fibers in the silicone elastomer, which increases the cross-link density, thereby leading to increased hardness. The result of study is in agreement with Andreopoulos, et al. in 1994 [18] who evaluated the addition of different fibers into elastomeric silicone. The study performs the addition of short glass fibers, aramid fibers and ultrahigh modulus polyethylene fibers. The result of study shows significant increase of material hardness