45 Maxillary implant overdentures: surgical templates in atrophic jaws Belgium) a bone-supported template was designed and partially extended to the nasal aperture (Figure 3.2). Every implant location had a width compatible with the implant manufacturer’s drill sleeves, which were in close contact with the bone. The designed template was exported as a ‘Surface Tessellation Language’ (STL)-file for manufacturing using medical grade polyamide powder for selective laser sintering (Oceanz BV, Ede, The Netherlands). Figure 3.2 | Template design. Notice the brackets in the anterior nasal aperture forcing the template into position ensuring an exclusive fit. Also note the two holes that were added to be able to get a good retention of the template. In none of our patients, however, we had to insert screws to allow for the required stability of the template as the template was stable without the use of screws. Surgical procedure All the patients were treated by one surgeon (GMR). The surgical procedure is shown in figure 3.3. The templates were autoclaved before use. Four patients were treated under general anaesthesia, the other seven patients were treated with local anaesthetics (Ultracain® D-S forte, Sanofi Aventis, Gouda, Netherlands). First, the crest of the alveolar process was incised and the buccal aspect of the mucosa was reflected up to the nasal anterior aperture after raising a full thickness flap. The two template brackets were then positioned on the nasal aperture, followed by placing the template in full contact with the underlying bone. Next, consecutive diameter drill sleeves were used to guide the implant drills during osteotomy, following the manufacturer’s instructions. Then the template was removed and the implants (Nobel Active NP 3.5mm, Nobel Biocare®, Zurich, Switzerland) were placed with a minimum torque of 45 Ncm. If present, small bone dehiscences were covered with intra-orally harvested bone and a resorbable membrane (Bio-Gide®, Geistlich Pharma North America Inc., Princeton, USA). Lastly, after the insertion of cover screws, the flap was repositioned and sutured. 3
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