Utilising the nasal aperture for template stabilisation for guided surgery in the atrophic maxilla

Pieter Onclin, Joep Kraeima, Bram B. J. Merema, Henny J. A. Meijer, Arjan Vissink, Gerry M. Raghoebar

Templates aim to facilitate implant placement in the prosthetically preferred position. Mucosa-supported and bone-supported templates are commonly used in the edentulous maxilla. In the atrophic maxilla (Cawood V and VI), however, these templates can be easily displaced due to a lack of supportive tissues, even in cases where anterior sites offer sufficient bone for implant placement. To assist in positioning and stabilisation, we designed a template that utilises the nasal aperture as a fulcrum to create a forced and exclusive fit. The aim of this study was to assess the clinical usability of the developed template and the corresponding implant placement accuracy in patients with edentulous atrophic maxillae. Deviations between planned and placed implant positions were measured by aligning pre- and post-operative cone beam computed tomography scans. Twenty-four implants were placed in 11 patients. One template did not fit properly due to a slight undercut. All implants could be placed with good primary stability. The implants had high accuracy at the implant shoulder (global deviation 1.1 ± 0.5 mm, lateral deviation 0.8 ± 0.5 mm) and a mean angular deviation of 7.2 ± 3.4°. The developed surgical template offers stabilised and secure template placement in the edentulous atrophic maxilla, resulting in satisfying implant placement accuracy when using a semi-guided approach. Netherlands Trial Register, NL6561, registered 26 September 2017.