This study investigated the pressure distribution of the implant-supported RPDs with the stress breaking attachments under occlusal force.
Materials and Methods
A model simulating a mandibular bilateral distal extension missing was fabricated using silicone impression material similar to soft tissues. Five pressure sensors were attached on the alveolar ridge. Two implants were placed at the bilateral second molar regions. Implant-supported RPDs, with the non stress-breaking connection (healing cap: HC) and the two stress-breaking connection (SBB attachment: SBB, magnetic attachment: MG) were fabricated. For a conventional RPD (CRPD), healing screws were placed without being connected to the implants. Loads up to 5kg were applied, and the pressure and displacement of the RPDs were simultaneously measured and analyzed.
The amount of total pressure of HC and MG was significantly less than for SBB and CRPD (p<0.05). The denture displacement of HC and MG tended less than for CRPD and SBB.
The implant placement at the distal edentulous ridge can prevent denture displacement of the distal extension bases. Within the in vitro limitations, precise denture settling and pressure distribution under the denture base could be controlled using an SBB attachment.