Anchorage effect of osseointegrated vs nonosseointegrated palatal implants

Palatal implants can be used with a transpalatal arch (TPA) connected with the second premolar to provide anchorage. The purpose of this study was to compare the anchorage effects of an osseointegrated palatal implant (OPI) with a nonosseointegrated palatal implant (NOPI), using finite element analysis. One model, which was composed of two maxillary premolars, periodontal ligament (PDL), alveolar bone, a palatal implant, palatal bone, a bracket, band, and TPA, was created on the basis of the clinical situation. The palatal implant was treated as either NOPI or OPI. The force on the premolars was investigated under three conditions: a distomesial horizontal force, a buccolingual horizontal force, and a vertical intrusive force. The PDL stress was calculated and compared with a model without an implant. The result showed that OPI could reduce PDL stress significantly. (The average stress was reduced by 14.44% for the distomesial horizontal force, 60.28% for the buccolingual horizontal force, and 17.31% for the vertical intrusive force.) The NOPI showed almost the same anchorage effect as OPI. The stress on the NOPI surface was higher than that on the OPI surface, but the stress was not high enough to result in failure of the implant. These results suggested that waiting for osseointegration might be unnecessary for an orthodontic implant.