Dental Tribune U.S. Edition

Dental Tribune U.S. Edition | October 2014A18 Prosthesis rehabilitation achieved despite need to use damaged spherical abutments By Carlo Borromeo, Dental Technician, Italy For more than 20 years, the 70-year-old female patient had used a total upper pros- thesis along with a lower prosthesis that wassupportedbytwosphericalmetalabut- ments attached to retentive titanium. She came to the clinic for restoration of the two prostheses, both of which had been extensivelydamagedbymanyyearsofuse. Additionally, the attachments, constructed of gold, had lost all retention ability. In the initial exam, extensive damage was noted with the attachment spheres (Fig 1). But to contain costs, the patient request- ed that the spheres not be replaced. So the spheres’ diameters were measured, and an individual impression carrier was con- structed to obtain the definitive impres- sion and the registration. Once the teeth montage was completed, function and esthetics were established (Fig. 2). Lingual and vestibular (Fig. 3) silicon maskswerebuilt.Thesiliconmasksprovide useful indications in choosing the proper box for the retentive caps and for evaluat- ing if there is enough space to build a metal structure to make the prosthesis more sta- ble and resistant. It was decided to use Rhein’83 elastic caps, which proved to be perfectly compat- ible with the spherical abutment diameters and enabled personalization of the pros- thetic by creating elastic retention suitable to this specific case. The reinforcement structure was con- structed by using wax in the space be- tween the tissues. The retentive caps were adapted over the spherical abutments and surrounding area, enabling isolation of a defined space where the two castable boxes for caps positioners could be placed Ad Fig. 2: Lower teeth montage. Fig. 3: Occlusal view of the model with silicon vestibular mask. Fig. 4: Space creation using wax. Attach- ments zone isolation. Position rings insertion over the spheres with Ot Box Classic boxes in position. Fig. 5: Space analysis using vestibular masks. Fig. 6: Structure building with vestibular masks. Fig. 7: Completed structure using vestibular mask, before sprue procedure. Fig. 8: Fusion testing on the model after sprue procedure and investment removal. Fig. 9: Metal structure testing following the cleaning process. Fig. 1: Damaged attachment spheres. Photos/Carlo Borromeo ” See PROSTHESIS, page A19 LAB INDUSTRY Clinical

Dental Tribune U.S. Edition

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