Clinical
Fig 4 Framework try-in close-up
Fig 9 Prosthesis and lip repositioning Fig 5 Lower jaw condition Continued » Fig 6
Hybrid acrylic-composite prosthesis fabri- cated with screw-retaining inserts
by four implants and splinted with a bar 3. a screw-retained hybrid bridge on six dental implants replacing facial support and utilising prosthetic replacement of tissue support but with no grafting or sinus work 4. A full hard and soft tissue reconstruc- tion with hip grafting and up to eight dental implants and a cement-retained bridge. After discussion the patient opted for
the screw retained prosthesis based on six dental implants and decided against extensive and invasive reconstructive surgery. From this point the treatment plan could commence.
Fig 7 Hybrid acrylic-composite prosthesis
Initial tests ı. Impressions 2. face bow record 3. photographs 4. study models and new temporary denture made to correct OVD, bite and to evaluate tissue support required 5. CT Scans of Upper Jaw with correct prosthesis in position to study hard tissue relationship and correct tooth position. Also required in order to ascertain the degree of bone volume/ density present.
Fig 8 Final fixation of the prosthesis
Surgical considerations In such cases my approach is firstly to ascertain the corridor of bone that lies between the medial wall of the maxillary sinus and its position. In order to gain this information one must be familiar with the manipulation of the CT scan image. Often RAW data
is needed to draw the correct cross sectional curve along the desired axis of Implant placement. Pre-Formatted scans on some software platforms may not allow the operator to manipulate this curve. The corridor of bone exists in most
patients and can accommodate a longer implant fixture whereby the cervical implant head can lie distal to the apex of the implant hence negating the need of a sinus graft and allowing the implant to be placed more distal in the arch. For inexperienced implant dentists
a surgical guide to triangulate this position exactly is an absolute requirement. In practice this area can be marked out as the zygoma has a distinct curvature on exposure of the maxillary jaw. Where the curva- ture or bulbosity starts is usually the position of the medial wall of the maxillary sinus, then by use of osseotomes/bone expanders, drills and re confirming this position can be achieved in two ways. Perforation into the sinus via the
lateral wall and palpation of the medial wall and mark points at 3,6,ıımm - or by intra oral X-rays and check the osteotomy site for perforations during surgery. I recognize these are not ever as accurate as a CT-guided stent and the author would always recommend a bone supported stent in these cases as apposed to a soft tissue supported guide. The other consideration is the space along the horizontal plane to place
Continued » Scottish Dental magazine 51
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