Background and objectives: The purpose of this paper is to evaluate the potential of 3D image acquisition by means of the CBCT triple scan protocol to calculate 3D virtual mandibular autorotation.
Methods: The centre and arc of rotation of the mandible in 50 consecutive prospective orthognathic cases were calculated. ‘CBCT scan 1’ was performed in centric relation while ‘CBCT scan 2’ was performed with a forced opening of the bite due to the thickness of the Alginot all-in-one impression. In order to evaluate the mandibular displacement between ‘CBCT scan 1’ and ‘CBCT scan 2’, both CBCT scans were rigid registered on the maxillary anatomy using voxel-based registration (Maxilim).
Results: In only 25% of the cases no condylar dislocations or translations did occur. This finding was explained by the fact that ‘CBCT scan 2’ was not performed in centric relation in the original protocol. Therefore another 50 consecutive orthognathic cases were analysed that all underwent a modified CBCT triple scan protocol where the patient was scanned with an Alginot all-in-one impression taken also in centric relation.
Conclusions: Modification of the triple scan CBCT protocol allows to calculate the virtual centre and arc rotation of the mandible.
Key words: 3D; mandibular autorotation; virtual