Increasing surface area of powder can reduce setting time and increase microhardness even at lower pH values after hydration.

A single oral dose of Naproxen, Novafen and Tramadol taken immediately after treatment reduced postoperative pain following pulpectomy and root canal preparation of teeth with irreversible pulpitis.

No abstract

Artificial neural networks can act as a second opinion to locate the AF on radiographs to enhance the accuracy of working length determination by radiography. In addition, ANN can function as a decision-making system in various similar clinical situations.

While ceramic-to-metal bonding has been used in many applications, the actual chemical and physical factors leading to optimum bond strength are not well understood. In this work, several variables affecting the bonding between dental porcelain and a palladium alloy (85% Pd, 10% Cu, and 5% Ga) were investigated: 1) precoating the metal by sputtering various oxides before porcelaining; 2) peroxidation of the metal base before porcelaining; 3) porcelaining under reducing atmosphere; and 4) surface roughening at controlled levels before porcelaining. Using a modification of the push doughnut shear bond strength test to measure bond strength the following results were obtained. 1) Compared with standard "control" samples, the aluminum oxide precoated specimens showed a bond strength improvement of 46%, while the copper, manganese, and tin oxide precoatings exhibited smaller effects. 2) Preoxidation of the metal base led to pronounced bond strengthening (152%) by surface roughening as well as oxide formation. 3) Porcelaining under a reducing atmosphere severely reduced bond strength (88% lower than the controls) indicating the role of oxidation during the standard firing cycle. 4) Mechanical roughening of the surface by controlled amounts gave pronounced improvements with greater notch depth. Coarse roughening produced the highest bond strength improvements (486%).

Mapping BSE and SE micrographs helped us to better understand the structure of materials on the surface of root canal dentin and MTA. Moreover, analysis of structure of materials on the surface of root canal dentine and MTA can be performed better by mapping of BSE and SE micrographs.

Mercury Intrusion Porosimetry technique is a promising and reliable technique for assessing the porosity of endodontic materials.

Relatively little is known about the microstructure of cobalt-base alloys in dentistry. Manufacturers of dental cobalt-base alloys have published very little on this subject. No research has been conducted on the microstructure of the cobalt-base alloys used in dentistry. The need for research in this field is recognized, however, by both the manufacturers of the alloys and researchers in the dental field.It appears that it would be profitable to dentistry if a study were made in which the effect of different casting conditions on the grain size and the microstructures of the cast product was established. It would also be useful to determine the physical properties of cast pieces having different microstructures. Today the mechanical properties listed for dental alloys vary a great deal from one type of alloy to another and also within the alloy. For example, elongation values from very small values to as high as 12 per cent are given for these alloys, and the modulus of elasticity determined for these alloys varies from approximately 20 to 40 million pounds per square inch.1 2 No satisfactory explanation is given for such a wide range of different physical properties. A study seems to be in order, therefore, to check these values and to determine whether such a variation is inherent in these alloys or is due to different testing conditions, such as sample size, casting condition, or equipment used. With these problems in mind, this study was undertaken in an effort to answer, with a certain amount of confidence, some of the above questions, the importance of which is becoming increasingly more obvious to the dental profession. MATERIALS AND METHODSIn this study more than 120 specimens were cast under different conditions, and their physical properties as well as their microstructures were studied. All specimens were cast of a cobalt-base alloy* which is of a composition similar to a typical dental alloy.t The investment used was a phosphate-bonded type.: Specimen size and manner of spruing were patterned after the recommendation of the A.D.A. specification for chromiumcobalt alloys.3 The conditions studied were related to changing the metal casting tem-