Abstract
BACKGROUND: The rehabilitation of the atrophic maxillae with dental implants represents a challenge that can be addressed with zygomatic dental implants and traditional axial implants. In the event of a severely atrophic pre-maxilla, a quad-zygoma approach may be necessary to provide anchorage for the fixed restoration. The proximity of anatomical features can increase the possible morbidity of the quad-zygoma approach and instead, trans-nasal implants may serve as a viable anterior anchorage alternative in the atrophic pre-maxilla region. METHODS: A total of 10 patients diagnosed from a class 2B edentulism received a combined treatment with trans-nasal implants paired with a single zygomatic implant were included in this study. Trans-nasal implant marginal bone level changes were evaluated on CBCT (Cone Bean Computed Tomographic) images taken immediately after trans-nasal implant placement and 1 year of follow-up post loading. The reference point for the CBCT measurement of mesial and distal bone loss after 1 year was the horizontal interface between the implant and the abutment. Secondary measurements taken at the 1 year follow up measured the amount of bone available in the sub-nasal, lateral and apical areas of the dental implant in contact with bone. RESULTS: The retrospective CBCT analysis of 18 trans-nasal implants (size ranging from 22 to 25 mm with an average of 24.1 mm) placed in 10 patients (all 10 patients were female ranging from 38 to 67 years old with an average age of 59.1 years old) shows an average marginal bone loss of 0.70 mm over a time period of 1 year following restorative loading, P < 0.0001. While the sub-nasal, lateral and apical engagement shown respectively 5.46, 12.92, and 2.70 mm of radiographical bone contact with the implant. CONCLUSION: The marginal bone loss observed in trans-nasal implants 1 year post loading is comparable to the marginal bone loss of conventional implants under similar conditions. The cumulative radiographical bone to implant contact between the subnasal and the apical bone seems to be of a value of 8.16 mm which seems to correspond to the size of a conventional dental implant. Therefore, it is believed that trans-nasal implants can be considered as an acceptable anterior anchorage alternative to the superior/ anterior zygomatic dental implant in the atrophic pre-maxilla region when paired with a single posterior zygomatic implant.