D.M مراجعه

مراجعه سريعه للدي ام ✅️👇 Lec 1 click here Lec 2 click here Lec 3 click here Lec 4 click here Lec 5 click here Lec 6 click here Lec 7 click here Lec 8 click here Lec 9 click here

Avoidance of wax distortion: 1. Minimal carving 2. Minimal change in temperature. 3. Minimal storage of the pattern (Invest immediately). 4. Use warm instruments for carving. 5. Store in fridge if necessary

3. Impression wax: They are previously used to make impression .

:2. Processing wax: A. Beading wax , used to make beading around the impression before pouring gypsum to protect the margins __ Boxing – in wax: used to make box around the impression ____ C. Block – out wax:to block – out undercut areas ___ Sticky wax: used for temporarily joining two components of an appliance and join the broken pieces of the denture before repair

Classification of waxes according to the their Application in Dentistry / 1. Pattern wax وبيه عدة انواع ، A.Inlay wax: They are used to make inlays crowns and pointic replicas. They are mostly paraffin with carnauba wax. (direct technique، Indirect technique) ____ B_ Denture casting wax : It is mostly green sheet.used to produce the metal components of cobalt – chromium partial denture. based on paraffin wax with bees wax ___ C_Modelling waxes : supplied in pink sheet form consist mainly of mixtures of paraffin wax and bees wax points in the range 49–58ºC. It is used to form the base of the denture and in setting of teeth ------------ D_ White wax:: to make pattern simulate veneer facing in crowns.

اما النوع الثاني (المصنع) 2_Synthetic Waxes واللي تكون خصائصه محدده من قبل المصنع

Classification of waxes according to their origin: 1. Natural waxes وبيه عدة انواع : mineral Animal waxes Plants waxes

Applications : formation of wax pattern to box impressions prior to cast pouring with gypsum Used as a base plate for the registration of jaw relationships Used as a casting wax to establish minimum thicknessto certain areas Used as a utility wax to prevent distortion of impression materials. Used as a sticky wax to join fractured parts together. Used as a corrective impression wax to contact and register the detail of soft tissues.

هسه نبلش ب Lec 9 Dental waxes

Care of the cast لازم ما نغسله بماء عادي . ليش ؟! لان تذوب الطبقه الخارجيه شنو نستعمل ؟ نستعمل محلول خاص اسمه "slurry water '‘.

عدنه اختبارين لل setting time الاول عباره عن ابره (نيدل) وعليها وزن نراقبها لحد ما gloss is lost الثاني عباره عن heavier needle

بالنسبه لل Tensile strength Gypsum is a brittle material, the tensile strength of dental stone is twice than that of plaster _It is significant in fracture of teeth in the cast while separating from the impression,

4_Chemicals اضافة هذي المواد يقلل ال strength ليش؟! This is due to the reduction in the inter crystalline cohesion

3_Drying اذا كان بالحاله Wet يعني بيها water راح يكون ال strength قليل اما اذا كان dry راح يكون ال strength ضعف الحاله الاولى

3_ Mixing اذا كان بشكل صحيح راح تزيد عدنا ال strength اما اذا صارت عدنه زياده بال Mixing راح يقل ال strength ليش؟! لان يصير عدنا تكسر بال crystals

2_ Porosity نعاملها معاملة ال W/P لان عند ما يزداد تزداد ال Porosity واكيد هنا يقل ال strength

Factors effecting the Strength : 1. W/P ratio لمن يزداد هذا المعدل يقل ال strength ليش؟! The excess water reduce the cohesion between the crystals themselves 40% of the strength يقلل الترابط بين الجزيئات