Oblique or orthoradial CBCT slices for preoperative implant planning: which one is more accurate?

Abstract

Aim: To assess which slice inclination would be more accurate in measuring sites for implant placement: the oblique or the orthoradial slice. Methods: Five regions of eight edentulous mandibles were selected (incisor, canine, premolar, first molar and second molar). The mandibles were scanned with a Next Generation i-CAT CBCT unit. Two previously calibrated oral radiologists performed vertical measurements in all the selected regions using both the oblique and orthoradial slices. The mandibles were sectioned in all the evaluated regions in order to obtain the gold standard. The Wilcoxon signed rank test compared the measurements obtained in the oblique and orthoradial slices with the gold standard. Results: The bone height measurements for the first and second molar regions using the orthoradial slices were statistically different from the gold standard. Conclusions: Using the orthoradial slices to obtain cross-sectional images may offer insufficient accuracy for implant placement in the posterior region.

Analysis of anatomical landmarks of the mandibular interforaminal region using CBCT in a Brazilian population

“…However, CBCT is a modern imaging technique, providing a more precise three-dimensional evaluation, enabling the identification of anatomical variations 5 . In order to get a better visualization of anatomic structures and clinical applicability, the present study opted to use images of this type for examination.…”

“…The use of appropriate imaging techniques is therefore essential to enable the accurate identification and location of these vital structures, avoiding potential injuries when surgical procedures are performed in the mandibular interforaminal region, including insertion of dental implants, mentoplasty and rehabilitation after trauma 4 . Cone-beam computed tomography (CBCT) is a relatively new imaging modality that provides a detailed evaluation of important bony structures 5 . This technique has high resolution, a relatively low radiation dose and produces images that demonstrate on different planes the real size of anatomical structures of the interforaminal region [6][7] .…”

The visibility of mandibular canal on orthoradial and oblique CBCT slices at molar implant sites

“…In the study of Neves et al, [20] a comparison was made between bone height measurements on oblique, orthoradial CBCT slices, and dried mandibles with the latter being the gold standard. At molar implant sites, the orthoradial slices were found inaccurate for such measurements.…”

“…This could be due to different visibility of the crest of the ridge or the inferior border of the mandible which were used for bone height measurements. In the same study of Neves et al, [20] the slice angulation used for obtaining oblique CBCT slices was not reported and the visibility of mandibular canal was not studied. In clinical dental implant practice, the bone height must be measured from the crest of the ridge till the superior border of the mandibular canal, [3] in order to avoid injury to the canal at the time of implant placement.…”

“…[18] In addition, titling increases the amount of bone available for osseointegration. [19] In one recent study by Neves et al, [20] cross-sectional CBCT images were generated by using two different slice inclinations: orthoradial and oblique. Although the main focus of interest of Neves et al [20] was the height of the mandibular body and not the visibility of the mandibular canal, they reported that bone height measurements on orthoradial slices were statistically different from the gold standard at mandibular molar implant sites.…”