The supra-gingival portion of the teeth in (a duplicate of) the stone model (see above) to be extracted will be carefully removed. The center of the future "extraction sites" will be identified. A rigid acrylic splint - a guide including a quartz marker (Dual Scan MarkerTM ( Materialize Dental NV, Leuven, Belgium)- will be produced. This guide will be used for the CBCT scans.