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ePaper created 2016-10-04, 09:33:57 | version 1.38.0
| cone beam supplement literature review 42 CAD/CAM 3 2016 Current and related literature abstracts Author_Dr Barry A. Kaplan, USA Relationship between preoperative Cone Beam Computed Tomography and intraoperative find- ings in sinus augmentation (Int J Oral Maxillofac Implants.2015Nov-Dec;30(6):1244-8.)(Figs.1a & b). Maxillary posterior areas present problems for plac- ingimplantsduetodiminishedboneheight,lowbone density and anatomic restrictions of the maxillary sinuses that lie above the alveolar ridges. When the residual ridge is 5 mm or less, a sinus augmentation procedureiscommonlyusedtoaugmenttheamount of available bone for implant placement. The maxil- larysinusmustbecompletelyevaluatedforanatomic and/orpathologicfindingspriortoanysurgicalinter- vention. Failure to do so could lead to post-operative surgical morbidity, such as infection. Cone Beam Computed Tomography (CBCT) is becoming the gold standard for pre-operative Sinus examination due to its low distortion and comparatively low radiation comparedtoconventionalCT.Althoughtheradiation dosage is slightly higher than a panoramic X-ray, you have the added advantage of viewing the sinuses in 3 dimension. The most common complication during sinus surgery is membrane perforation resulting during the opening of the bony window or during elevation of the membrane. This study compared pre-operative CBCT to intraoperative findings to see if there was greater risk of perforation during eleva- tion in the presence of bony septum, thin Schneider- ian membranes and reduced residual ridge height. PreoperativeScans from an ICAT Next Gen CBCT (Im- agingSciencesInternational,Hatfield,PA)weretaken and evaluated for several criteria. Bony septum were evaluatedusingaxialslices,Membranethicknesswas measured using the coronal slices and the residual ridgesevaluatedusingsagittalslices.Also,intraoper- atively, it was noted whether perforation occurred and how long the surgery took. The results were that membrane perforation occurred in 24.5 % of the cases. In cases with the presence of septum, mem- brane perforation occurred 57.1 % of the time. Other studies have suggested that the presence of septum isthereasonformembranethinness.Whilethemean membranethicknessinthestudywas3.96±2.01mm, there was no significant correlation between mem- brane thickness and occurrence of perforation. Also,theresidualridgeboneheighthadnosignificant correlation with the occurrence of membrane per- foration. In summary, CBCT is an important tool in thepreoperativepatientevaluationsothatsinussep- tum can be identified to reduce the risk of membrane perforation. Accuracy and reliability of Cone Beam Computed Tomographic measurements of the bone labial and palatal to the maxillary anterior teeth (Int J Oral Maxillofac Implants. 2015 Nov-Dec;30(6): 1249-55.) (Figs. 2a & b). Maintainingtheintegrityofthemaxillarybuccalplate during immediate implant extraction is critical to the aesthetic outcome. Direct clinical measurement of the facial plate in other studies showed the facial plate to range from 0.8 to 1.4 mm. Conversely, mea- Fig. 1a: Panoramic view of septa. Fig. 1b: Axial view of septa. Fig. 2a: Measurement of labial plate using calipers. Fig. 2b: Cross-section of maxillary anterior tooth. Blue lines on left demarcate measurements along the labial plate. Blue lines on the right demarcate measurements on the palatal plate of bone. Fig. 1a Fig. 1b Fig. 2a Fig. 2b 32016