Title	Cone Beam CT Is Superior To Multi-Slice CT For Implant Site Measurements
Clinical Question	For patients requiring implant placement, does Cone Beam Computed Tomography (CBCT) that uses lower radiation dose provide measurements with improved accuracy compared with Multi-Slice CT (MSCT)?
Clinical Bottom Line	CBCT imaging provides increased measurement accuracy (measurement error=2.3%) for implant placement compared with MSCT (measurement error=5.4%-6.6%) and uses lower radiation dose. (See Comments on the CAT below)
Best Evidence
PubMed ID Author / Year Patient Group Study type (level of evidence) 18195249 Suomalainen/2008 1 Cadaver Case Study Key results A cadaver mandible was imaged with CBCT and MSCT using variable radiation doses, and comparable vertical and horizontal linear measurements were made. Selected sites of the mandible were measured by 2 Oral and Maxillofacial Radiologists (who were blinded from one-another) during two sessions at 2 week intervals. The mandible was cut into 4 mm thick slices at three marked locations and measurements were made and compared with the corresponding sites on the CT images. Mean measurement error values of CBCT (2.3%) were superior to MSCT measurements (5.4-6.6%) p=0.022. There was little difference in intra- and inter-examiner repeatability. The radiation dose values MSCT scanners were within the ranges of 3.2–30.7 mGy cm and 18.7–171.8 mGy cm, respectively. The dose values measured in CBCT were 2 mGy cm in the central scan region and 1 mGy cm in the peripheral region of the head phantom. Lowering the MSCT radiation dose to less than a quarter of its conventional original value did not significantly affect the measurement error.
Evidence Search	#3 Search edentulous #2 Search accuracy of conventional CT#1 Search accuracy of cone beam CT
Comments on The Evidence	In vitro studies are usually viewed as low level evidence; however, the cadaver specimen used in this study simulates an in vivo study. This study could not be done in vivo due to the need for verification of measurements and the use of multiple radiographic exposures. Therefore, this evidence can be considered good.
Applicability	The study revealed the value of CBCT as an accurate treatment planning tool for implant placement. Radiation dose of CBCT is less than medical MSCT, however, because doses vary widely between different CBCT scanners and protocols used in MSCT settings, appropriate machine settings are essential to use the least radiation exposure. Although statistically significant, the superior accuracy of measurements achieved using CBCT may or may not be clinically significant considering the size of the mandible and space available for implant placement. Cone Beam Computed Tomography units are more convenient to dental patients compared to MSCT units that are located in medical facilities. The financial cost of CBCT is lower than that of MSCT and provides ease of patient positioning.
Specialty	(Public Health) (Oral Medicine/Pathology/Radiology) (Endodontics) (General Dentistry) (Oral Surgery) (Orthodontics) (Periodontics) (Prosthodontics)
Keywords	Cone Beam CT, Multi-slice CT, implant, linear measurement
ID#	868
Date of submission	04/28/2011
E-mail	faddoul@uthscsa.edu
Author	Taoufik Faddoul
Co-author(s)
Co-author(s) e-mail
Faculty mentor	Stephen Matteson, DDS
Faculty mentor e-mail	MATTESON@uthscsa.edu
Basic Science Rationale (Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?) None available
Comments and Evidence-Based Updates on the CAT (FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs) by Mohammed Barayan (San Antonio, TX) on 07/10/2012 Another study proves that the application of CBCT for the indicated purpose yielded good results comparable to those of MSCT. All two measuring methods were feasible and accuracy was statistically not different between the data acquired by MSCT and CBCT, although this study used different methods of collecting the data but yet agrees somehow to the conclusion of this cat. (PMID: 22411262 )