Titanium for removable dentures. I. Laboratory procedures

To test the hypothesis that titanium (Ti) removable partial dentures (RPDs) would function for a period of at least 2 years without failure, 10 patients were selected to receive dentures made from Ti and Co-Cr. The Ti RPDs were constructed identically to conventional cobalt-chromium (Co-Cr) dentures. Five complete Ti dentures were also included and the laboratory procedures involved for making both complete and partial dentures were evaluated. The detection of internal defects by radiography made the screening of Ti castings possible and led to a rejection of specimens showing porosities of more than 0.5 mm in flexible members. Co-Cr frames on the other hand cannot be screened in this way. The success rate in the casting of Ti was 60% for both partial and complete dentures, but as casting technology has since improved, the rate is expected to be higher, particularly where complete denture palates have optimum thickness. The success rate in the casting of Co-Cr RPDs was 100% without radiographic screening. The weight difference between Ti and Co-Cr RPDs was in the range of 1.3 to 3.9 g at issue and is generally higher as the volume of denture frames increases. A large difference would be of clinical significance in maxillary complete dentures. The low density of Ti allows for the adoption of a useful pre-clinical quality-control process using commonly available dental X-ray units.