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CAD/CAM international magazine of digital dentistry No. 3, 2016

literature review cone beam supplement | 43 CAD/CAM 3 2016 surements of the facial plate using CBCT have shown a labial thickness ranging from 0.6 to 1.73 mm. This study evaluated buccal and palatal bone thicknesses in the anterior maxilla by CBCT and compared these with direct clinical measurements. After extraction, the labial plate was measured at 1 mm, 4 mm and 8 mm from the osseous crest and the palatal wall was measured from 1 mm and 4 mm from the osseous crest using a caliper. Additionally measurements were taken from a pre-surgical CBCT (NewTomVG, Voxel size 0.3mm). Mean thickness of the labial bone was 0.50 ± 0.32 mm and 0.76 ± 0.37 mm for direct and CBCT measurements respectively. The majority of the buccal sites had a thickness of <1 mm. For the palatal thickness, 1.16 ± 0.53 mm and 1.41 ± 0.5 1mm for direct and CBCT respectively. CBCT measurements overestimated measurements in 77% of the cases. As the thickness of the labial and palatal bone increased in thickness (greater than 1 mm) the discrepancy between the two methods of measurements decreased. Overall the differences betweenCBCTanddirectmeasurementwerenotclin- ically significant. Although, most studies have found that CBCT underestimates bone thickness this study found the opposite. One explanation for the over- estimationmightbetheresultofpartialbonevolume averagingandblurringofthinbonelayers.Inconclu- sion, CBCT measurements correlate well with clinical findings except when labial thicknesses are less than 1 mm. Evaluation of periapical lesions and their associa- tion with maxillary sinus abnormalities on Cone Beam Computed Tomographic images (J Endod. 2016 Jan;42(1):42-6.) (Figs. 3a & b) Pain in the maxillary posterior areas can sometimes be difficult to diagnose due to the proximity of the teethtothemaxillarysinusandtheyshareacommon nerve supply. Roots of maxillary teeth can come in verycloseproximityandevenprotrudeintothesinus. When periapical infections of the maxillary roots occur, infection can spread into the maxillary sinus causing inflammation. Sinus membrane thickening can be a sequelae in the presence of inflammation. When this occurs, it may be difficult to elucidate the sourceoftheinfectionwithatwo-dimensionalX-ray. CBCT offers better diagnostic capabilities because of its 3-D reconstructed images that can be viewed in several planes. This retrospective, cross-sectional study compared the presence, size and distance of periapical radiolucencies (RL), with the presence of sinus abnormalities using CBCT. Images from I-CAT Cone Beam (Imaging Science International, Hatfield, PA) were evaluated using a resolution of 0.25 mm voxels. Maxillary sinuses were assigned a number from 1–6 based on the type of pathology seen (eg. mucosal thickening, presence of polyps, opacifications). Periapical RLs were graded based on size. The results showed that 64.3% of the teeth with periapical RLs had maxillary sinus ab- normalities. The larger the periapical RL, the greater its association with maxillary sinus abnormalities (>8 mm had the highest correlation). Additionally, greater association with maxillary sinus abnormali- ties when the periapical lesion was <2 mm from the sinus floor. Mucosal thickening was the most com- monfindingwhenassociatedwithaperiapicallesion. In general, however, sinusitis of odontogenic origin accounts for 10–20% of all maxillary sinusitis cases. Thisisbecausethesinusflooractsasabarriertoden- tal infection. In conclusion, the study showed sinus abnormalities were highly correlated with periapical RLs that were in very close proximity to the sinus. CBCTisausefultoolforvisualisingthemaxillaryroots and their proximity to the sinuses._ contact Dr Barry A. Kaplan, Prostho- dontist, Bloomfield, NJ, USA. Past President of the NJ Sec- tion of the American College of Prosthodontists, Fellow of the International Congress of Oral Implantologists (ICOI). www.kaplandentistrynj.com Fig. 3a Fig. 3b Fig. 3a: Mucosal thickening and periostitis. Fig. 3b: Antrolith. 32016

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