Background and purpose - Additional screw fixation of the all-polyethylene press-fit RM cup (Mathys) has no additional value for migration, in the first 2 years after surgery. However, the medium-term and long-term effects of screw fixation remain unclear. We therefore evaluated the influence of screw fixation on migration, wear, and clinical outcome at 6.5 years using radiostereometric analysi...

Not only can teeth provide clues about diet, but they also can be indicators of habitat quality. Conspecific groups living in different habitats with different kinds of foods may exhibit different rates of dental attrition because their teeth are less well adapted to some foods than to others. Ecological disequilibrium describes the situation in which animals live in habitats to which they are ...

Clinically the low wear of self-pairing aluminaceramic type BIOLOX (Feldmühle/CERASIV) in the self-locking AUTOPHOR and cemented XENOPHOR prosthesis (Osteo AG) was confirmed radiographically after 10 years (29) and recently after 20 years (33) of clinical experience. In laboratory measurements of retrieved prostheses (chiefly after infection or aseptic loosening) the low wear rate of ceramic se...

Tooth wear records valuable information on diet and methods of food preparation in prehistoric populations or extinct species. In this study, samples of modern and prehistoric hunger-gatherers and agriculturalists are used to test the hypothesis that there are systematic differences in patterns of tooth wear related to major differences in subsistence and food preparation. Flatness of molar wea...

We report the long-term radiological results of 58 total hip arthroplasties (THA) using the Charnley offset-bore acetabular socket. Wear was measured at four sites and radiolucent lines and possible migration were recorded. Four cups were retrieved at revision and were examined using light microscopy, SEM and X-ray microanalysis. At a mean follow-up of seven years the mean wear in the DeLee and...

Particle effects on friction and wear of 6061 aluminium (6061 AI) reinforced with silicon carbide (SIC) and alumina (AI203) particles were investigated by means of Vickers microhardness measurements and scratch tests. Unreinforced 6061 AI matrix alloy was also studied for comparison. To explore the effect of heat treatment, materials subjected to three different heat treatment conditions, i.e. ...

Glass-ceramic materials were developed from gabbro including MgO and Al2O3 additives. Heat treatments for phase transformation from glassy matrix to glass-ceramic were carried out at 1000 ◦C for 3 h. X-ray di raction studies conducted on the glass-ceramic samples revealed that the phases formed in the glass-ceramics were cordierite, anorthite, diopsitic augite, forsterite and andesine. Glass an...

The fast monitoring of tool wears by using various Cutting signals and the prediction models developed rapidly in recent years. Comparatively, various wear forecast models based on artificial neural networks (ANN) perform much better in accuracy and speediness than the conventional prediction models. Combining the prominent dynamic properties of back propagation neural network (BPNN) with the e...

This multicentre study analysed 12 alumina ceramic-on-ceramic components retrieved from squeaking total hip replacements after a mean of 23 months in situ (11 to 61). The rates and patterns of wear seen in these squeaking hips were compared with those seen in matched controls using retrieval data from 33 'silent' hip replacements with similar ceramic bearings. All 12 bearings showed evidence ch...

The African apes possess thinner enamel than do other hominoids, and a certain amount of dentin exposure may be advantageous in the processing of tough diets eaten by Gorilla. Dental wear (attrition plus abrasion) that erodes the enamel exposes the underlying dentin and creates additional cutting edges at the dentin-enamel junction. Hypothetically, efficiency of food processing increases with j...