Measurement Study On The Implant Area Of Maxillary Sinus With Spiral CT Virtual Endoscopy

Objective: To evaluate the value of spiral CT virtual endoscopy in measurement ofthe anatomical structure of the maxillary sinus and alveolar bone density of planting areas,and discuss the clinical significance of spiral CT virtual endoscopy in the maxillarysinus elevation surgery.Methods: In60cases, maxillary sinuses were scanned and three dimensionalreconstructed by spiral CT before and after the operation.①As the benchmark of ZAC（Zygomatic Alveolar Crest）line, the length and width of maxillary sinus were measured,and the lowest position of the sinus floor and sinus septum were demonstrated oncomputed workstation.②Alveolar bone of60cases were scanned and three dimensionalreconstructed with spiral CT, the Hounsfield Unites of60ring zones around potentialimplant sites were measured on computed workstation, and the corresponding sites bonedensity were classified with Lekholm and Zarb grouping.③Intra sinus images weredemonstrated by spiral CT virtual endoscopy before and after the sinus elevatedoperation.④Spiral CT virtual endoscopic sinus images were compared with endoscopicsinus images.Results: The maxillary sinus morphosis were demonstrated by Spiral CT virtualendoscopy before the sinus elevated operation, the images were similar to theendoscopic images. The length of maxillary sinus was29.38±4.99mm, the width ofmaxillary sinus was18.17±3.43mm. There were11(18.33%) sinus septum in60cases.The average effective alveolar bone height was6.5mm. The mean bone density of ringzones (666.26±161.57HU) around potential implant sites was higher than the mean bonedensity of implant sites (580.75±151.68HU). All73implants were implanted and the“tent-like”images of maxillary sinus floor could be visible by spiral CT virtual endoscopy,the average tissue thickness of sinus floor covered the implant tip was2.5±0.8mm. Conclusion: The anatomical structure of the maxillary sinus can be demonstrated byspiral CT virtual endoscopy accurately, and alveolar bone density of ring zone aroundpotential implant site is more valuable. Post operational intra sinus image demonstrated byspiral CT virtual endoscopy is same as endoscopy image.