Accuracy of measuring the cortical bone thickness adjacent to dental implants using cone beam computed tomography.
OBJECTIVE
To assess the accuracy of measuring the cortical bone thickness adjacent to dental implants using two cone beam computed tomography (CBCT) systems.


METHODS
Ten 4 x 11 mm Astra Tech implants were placed at varying distances from the cortical bone in two prepared bovine ribs. Both ribs were scanned in a reproducible position using two different CBCT scanners. Ten examiners each carried out four measurements on all 10 implants using the two CBCT systems: vertical distance between the top of the implant and the alveolar crest (IT-AC), and thickness of the cortical bone from the outer surface of the implant threads at 3, 6 and 9 mm from the top of the implant. Ground sections were prepared and bone thickness was measured using a light microscope and a graticule to give a gold standard (GS) measurement.


RESULTS
The examiner's measurements were significantly different between CBCT systems for the vertical and thickness dimensions (P<0.001) while measuring the cortical bone thickness between 0.3 and 3.7 mm. Within that range, i-CAT NG measurements were consistently underestimated in comparison with the GS. Accuitomo 3D60 FPD measurements closely approximated the GS, except when cortical bone thickness was <0.8 mm. The mean percentage errors from the GS at 3, 6 and 9 mm measurement levels were 68%, 28% and 18%, respectively, for i-CAT NG and 23%, 5% and 6%, respectively, for Accuitomo 3D60 FPD.


CONCLUSIONS
Within the limitations of this study, it was concluded that i-CAT NG (voxel size 0.3) may not produce sufficient resolution of the thin cortical bone adjacent to dental implants and, therefore, the measurements may not be accurate; whereas, Accuitomo 3D60 FPD (voxel size 0.125) may produce better resolution and more accurate measurement of the thin bone.
Razavi
Touraj
T
Department of Restorative Dentistry, King's College London Dental Institute, London, UK.
Palmer
Richard M
RM
Davies
Jonathan
J
Wilson
Ron
R
Palmer
Paul J
PJ
D000539:Alveolar Process / Q000000981:diagnostic imaging*; D000818:Animals; D015519:Bone Density / Q000502:physiology*; D002417:Cattle; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation*; D015921:Dental Implants; D012016:Reference Values; D012272:Ribs / Q000601:surgery
D015921:Dental Implants