بررسي انقباض حجمي پس از پخت چيني دنداني )DENTIN-D4(DENTIN مورد استفاده در سيستم P.F.M و مقايسه آن با چيني دنداني DENTIN كارخانه VITA

Measurement of volume shrinkage of (Dentin-D4) Porcelain powder used in P. F.M system and comparing it with (vita Dentin) powder

Background & Aim: Dental porcelain is one of the best materials ever used in dentistry. Restoring and replacement of the teeth by porcelain fused to metal restorations is still the most commonly used approach. There fore, Mashad Dental School and Par-e-Tavoos research institute attempt to produce porcelain powder used in P.F.M. system. Method & Material: This is an experimental single blind invitro study. For this purpose Dentin powder was produced, observing vita Dentin porcelain powder (VMK 68M) (Vita Co. Germany) and ISO 6872 1995 (E) standard qualifications. First "Vita-dentin" powder was chemically analyzed using SEM, XRD, and XRF techniques to find the chemical formula of the powder and to make a similar powder using material from inside the country. After producing different powders, (Dentin-D4) powder was found to be physically and chemically similar to "Vita-Dentin". Different tests have been performed to be compatible with Vita porcelain which is one of the most universal dental porcelain in the world. One of the tests was to measure the shrinkage of porcelain after baking. For this purpose a stainless steel box was made with 25x5x2 mm diameter and filled with porcelain powder paste to make 10 blocks of Dentin-D4 and 10 blocks of Dentin-Vita and baked in Vita furnace. The dimensions of the blocks including length, width, and thickness was measure using a especial gauge and percentage of volume shrinkage was calculated. Results: The Mean volume shrinkage between two powders had a statistically significant difference (P<0.001)."Vita - Dentin" had a volume shrinkage of 33.07% while Dentin-D4, had 17.24%. Conclusion: 1- The mean volume shrinkage of all Dent-D4 was lower than Dentin-vitan. 2- The laboratory works are easier with Dentin-D4 than Dentin - vita due to less volume shrinkage of Dentin-D4.