34 I I case study _ Atrophic maxilla implants2_2012 Fig6_Sectionalviewofsinuscavity showingcompletelackofbone inferiortosinus. Fig7_Prosthesisfittingsurface Fig8_UL45Placement.Noteheadof implantUL4ismesialtoextractedsite Fig9_Postop-OPG. cided against extensive and invasive reconstructive surgery. From this point the treatment plan now started. Initial special tests carried out 1. 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 to correct tooth po- sition. And to ascertain degree of bone volume/density present. (Fig 1) _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 or- der 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 accommo- date a longer implant fixture whereby the cervical implant head can lie distal to the apex of the implant hence ne- gating the need of a sinus graft hence the implant is placed more distal in the arch. For inexperienced implant dentists a surgical guide to triangu- late this position exactly is an absolute requirement. In practice this area can be marked out as the zygoma has a Fig. 6 Fig. 7 Fig. 8 Fig. 9