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Title Comparison Studies Show Complementary Metal Oxide Semiconductor (CMOS) Digital Intra-oral Detector Out-Performing or Having Similar Overall Image Quality Then a Charge-Coupled Device (CCD) Detector
Clinical Question How does complementary metal oxide semiconductor (CMOS) digital intra-oral sensor compare to charge-coupled device (CCD) in image quality?
Clinical Bottom Line For clinicians considering digital intra-oral sensors CMOS technology offers similar or in some cases better image quality.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 24404600Shi/201325X25X10 mm Aluminum test phantom In vitro Comparison Study
Key resultsThe dose response function was constructed using 66 kVp and 8 mAm for an exposure range between 0 uC/kg and 10 uC/kg for ProSenor (CMOS) and Dixi (CCD) with both sensors having linear function between exposure and the grey levels. The dose response function was steeper for the ProSenor (CMOS) than Dixi (CCD) sensor. Paired t-test showed the perceptible low-contract detail to be significantly higher for CMOS than for CCD sensor, especially at low exposure levels (p<0.001). For the exposure levels at or above 31.8 uC/kg the perceptible details were significantly higher for CCD because the CMOS sensor reached its saturation point.
#2) 15070845Kitagawa/ 2003Formalin-fixed adult cadaver maxilla with soft tissue in placeRandomized Comparison Study
Key resultsThe image was acquisitioned at 70 kVp and 8 mA with exposure time from 0.05s-0.40s in 12 increments. Comparison between the image quality was made using odds ratio analysis with 95% confidence interval applied to determine statistical significance. Observers were asked to independently rate all images as 0= poor, 1= acceptable, 2= excellent. Proximal dental caries: No significant difference between sensors. CMOS received 88.9% acceptable/excellent image ratings compared with 86.7% for CCD. Gingival soft tissue: No significant difference with both detectors performing poor. Cortical bone: The CMOS detector was rated significantly better than CCD. CMOS image detector received 65.6% acceptable/excellent and CCD received 46.7%. Root canal space: The CCD detector was rated as outperforming CMOS with 92.2% acceptable/excellent rating compared to 53.3% for CCD. Root apices: The CMOS detector outperformed CCD with 95.6% acceptable/excellent for CMOS and 76.7% for CCD. Periodontal ligament space and endodontic instrument tip clarity: No significant difference was found. The Pearson product correlations for intra-rater were 0.694 for CMOS and 0.726 for CCD. Inter-rater reliability between observers was 0.974 for CMOS and 0.973 for CCD.
Evidence Search Pubmed search: Digital x-ray sensors, comparison of CMOS vs. CCD digital sensors, in-vitro
Comments on
The Evidence
Validity: The Gold standard in silicone based digital sensor technology is CCD. The X-Q Shi et al. study showed the dose response function of the two sensors having different slopes when plotted on a linear scale. The CMOS ProSensor having a steeper slope than the CCD Dixi sensor. This demonstrates a greater capacity of the CMOS sensor to record small exposure differences as well as higher contrast detail than the CCD sensor. This study also employed Perceptibility curve (PC) to demonstrate low-contract differences. The integral of the area under the PC curve for CMOS was doubled compared to CCD, which indicates a narrow contract detail. The H. Kitagawa et al. study, which utilized adult cadaver maxilla with soft tissue in place, randomly evaluated images from Schick CMOS and CCD sensors. Each observer evaluated for: 1.Proximal caries; 2.Gingival soft tissue; 3.Cortical bone; 4.Root canal space; 5.Root apices; 6.PDL space; and 7.Endodontic instrument tip clarity. Comparisons were made by use of odds ratio analysis applying a 95% confidence level. Combining the ratings from all observers for each of the features evaluated, there were almost equal numbers of excellent, acceptable and poor ratings for images made with CMOS and CCD detector. Perspective: In this digital age clinicians have to make a decision on replacing film based x-ray system to a digital sensor based. This study provides some guidance for clinicians when deciding to acquire either a CMOS or CCD sensor.
Applicability Regarding image quality, Kitagawa et al. found the two detectors to produce images of similar quality in seven different observation points while X-shi et al. found CMOS to more beneficial to patients owing to its reduced radiation dose and increased low-contract detail. On average the CCD sensor is more expensive. CMOS based technology provides an acceptable and cost effective alternative.
Specialty/Discipline (Oral Medicine/Pathology/Radiology) (Endodontics) (General Dentistry) (Oral Surgery) (Orthodontics) (Pediatric Dentistry) (Periodontics) (Prosthodontics) (Restorative Dentistry)
Keywords Digital sensors, image quality of CMOS and CCD digital sensors, CCD vs CMOS digital sensors.
ID# 2787
Date of submission: 11/25/2014spacer
E-mail aqil@livemail.uthscsa.edu
Author Salim Aqil, DDS
Co-author(s) e-mail
Faculty mentor/Co-author S. Thomas Deahl, II, DMD, PhD
Faculty mentor/Co-author e-mail DEAHL@uthscsa.edu
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