Maxillary sinus augmentation using computer-aided design/computer-aided manufacturing (CAD/CAM) technology.

BACKGROUND: Maxillary sinus augmentation is a common method for increasing bone height for insertion of dental implants. In most cases, the graft is manually cut into a roughly appropriate shape by visual estimation during the operation; accordingly, the shape of the graft depends considerably on the experience of the surgeon. We have developed a computer-aided design/computer-aided manufacturing (CAD/CAM) technique to generate custom-made block grafts for sinus augmentation, and a customized cutting guide to precisely position the lateral wall and facilitate membrane elevation, using cone-beam computed tomography (CBCT). METHODS: Custom-made blocks of hydroxyapatite (HA) were preoperatively cut to the required shape, based on a three-dimensional (3D) simulation, using CAD/CAM technology. The custom-made HA blocks were used for sinus augmentation. RESULTS: Five patients underwent bilateral sinus elevation with custom-made HA blocks. Six months later, implants were placed. Two years after placement, all implants were in function. No clinical or prosthetic complications were encountered. CONCLUSIONS: We present a CAD/CAM technique for the fabrication of custom-made block grafts for sinus augmentation.

Comparative study of jaws with multislice computed tomography and cone-beam computed tomography.

PURPOSE: The aim of this study was to compare the dosimetric and diagnostic performance of multislice computed tomography (MSCT) and cone-beam computed tomography (CBCT) in the study of the dental arches. MATERIALS AND METHODS: Effective dose and dose to the main organs of the head and neck were evaluated by means of thermoluminescent dosimeters (TLDs) placed in an Alderson Rando anthropomorphic phantom and using a standard CBCT protocol and an optimised MSCT protocol. Five patients with occlusal plane ranging from 54 cm to 59 cm who needed close follow-up (range 1-3 months) underwent both examinations. Image quality obtained with CBCT and MSCT was evaluated. RESULTS: Effective dose and dose to the main organs of the head and neck were higher for MSCT than for CBCT. Image quality of CBCT was judged to be equivalent to that of MSCT for visualising teeth and bone but inferior for visualising soft tissues. Beam-hardening artefacts due to dental-care material and implants were weaker at CBCT than at MSCT. CONCLUSIONS: When panoramic radiography is not sufficient in the study of the teeth and jaw bones, CBCT can provide identical information to MSCT, with a considerable dose reduction. MSCT is, however, indicated when evaluation of soft tissue is required.