IMPORTANT POINTS OF DENTAL MATERIALS BY Dr Maryum Malik (3)

101.
Beta plaster (110-120°C) —-》♧plaster of Paris
Alpha ( 125°C) —-》Dental stone /hydrocal
Heat gypsum with 30% CaCl —-》improved plaster type 4
102. Increase water powder ratio and accelerator will decrease setting expansion of gypsum
103. Percolation is associated with and Coefficient of thermal expansion is highest for Acrylic Resin.
104. KHN of Dentine is closest to Silicate Cement
105. Softening heat temperature increases ductility and reduces Tensile strength, Proportional Limits and Hardness 106. Stiffness is Resistance to Elastic Deformation
107. Sag Resistance resists plastic and creep flow under its own weight during porcelain fire and soldering
108. Amalgam cannot withstand high tensile stress
109. Amalgam Alloy contains Silver 65% Tin29% Copper 6%
110. Amalgam restoration not subjected to high biting stress for at least 8hrs
111. Amalgam restoration finishing done after 24hrs
112. Most common corrosion products with conventional Amalgam Alloy: Oxide of Tin Chloride of Tin
113. Tarnish—> surface discoloration of metal
114. Corrosion —> Actual deterioration of metal by reaction with its environment
115. Conventional cavity varnishes not use with Direct resin filling
116. Polymer / monomer ratio 3:1
117. GIC Powder/liquid ratio 3:1
118. Polycarboxylate P/L ratio 1.5:1
119. Dental porcelains are crystalline minerals in Glass matrix
120. Stages in firing of Dental Porcelain Low bisque Medium bisque High bisque
121. Shrinkage occurring during firing of porcelain is due to loss of water and densification through sintering
122. Cross Bend test for Dental cement, use to measure strength ( modulus of rupture)
123. Brush heap Structure Agar Agar
124. Sulphuric Ester of linear polymer of galactose is Agar
125. Chief Ingredient of Alginate is linear polymer of sodium salt of anhydro beta D mannuronic Acid
126. Increase Sprue length will cause increase in localized shrinkage porosity * Increase sprue Thickness will decrease localized shrinkage porosity
127. Increase Sprue length will decrease Sub surface porosity * Increase Sprue thickness increase Sub surface porosity
128. High %age of copper in Type 3 gold Alloy
129. Crown and short span Bridge type 3 gold alloy
130. For RPD type 4 gold alloy
131. Very dilute solution of carbon in Iron is “Ferrite”
132. Specific compound of Iron and Carbon (Fe3C) Is ”cementite”
133. Pearilite = Ferrite + Cementite
134. Sprue former should be attack to wax pattern at greatest bulk point
135. Process of heating cast alloy to eliminate coring is homogenization