This paper presents a new methodology to predict the wear for three-cone bits under varying operating conditions. In this approach, six variables (weight on bit, rotary speed, pump rate, formation hardness, bit type, and torque) were studied over a range of values. A simulator was used to generate drlling data to eliminate arrors coherent to field measurements. The data generated was used to es...

STATEMENT OF PROBLEM Surface of porcelain restoration is a matter of clinical concern because of its abrasive action on the opposing enamel. PURPOSE This study comparatively evaluated wear of enamel when opposed by three different surface finishes of ceramic. MATERIALS AND METHODS A total of 60 metal-ceramic discs (10 mm × 2 mm) with different surface finishes were fabricated. They were div...

The shape of shark teeth varies among species, but traditional testing protocols have revealed no predictive relationship between shark tooth morphology and performance. We developed a dynamic testing device to quantify cutting performance of teeth. We mimicked head-shaking behaviour in feeding large sharks by attaching teeth to the blade of a reciprocating power saw fixed in a custom-built fra...

Acid erosion of enamel is the chemical dissolution of the superficial layers of teeth without the presence of bacteria. If the presence and exposure of a demineralising agent such as vitamin C is frequent and prolonged, it can lead to significant tooth wear. This case report discusses one such presentation and as a result of the occlusal relationship, this serves to effectively demonstrate the ...

BACKGROUND Recently, incorporation of nanohydroxyapatite (NHA) has been suggested to improve the mechanical properties of glass ionomers (GIs). This study aimed to assess the effect of addition of NHA on wear of resin modified glass ionomer (RMGI) by tooth brushing simulation. MATERIAL AND METHODS In this in vitro, experimental study, NHA in 1, 2, 5, 7 and 10wt% concentrations was added to Fu...

The wear resistance of denture teeth is important to the longevity of removable prostheses of edentulous patients. The ability of denture teeth to maintain a stable occlusal relationship over time may be influenced by this property. The purpose of this in vitro study was to evaluate the wear resistance of polymethyl methacrylate (PMMA) denture teeth based on their chemical composition when oppo...