Use of spiral computed tomography for multiplanar dental reconstruction

OBJECTIVE: To compare spiral with conventional CT for multiplanar reconstruction (MPR) prior to dental implant placement. METHODS: Ten patients underwent conventional and then Spiral CT at 1 mm slice thickness. In six patients (Group A) the pitch was 1:1; the other four (Group B) it was 2:1. Image quality and clinical features were evaluated separately on axial and reconstructed images by two experienced radiologists who scored each parameter from 1 (poor, non-diagnostic) to 3 (good, diagnostic). RESULTS: Loss of spatial resolution with spiral CT was not significant and the diagnostic yield poorer only for trabecular bone structure. The MPRs were better and depiction of the mandibular canal more reliable. CONCLUSIONS: We recommend the use of spiral CT instead of conventional CT for dental MPR because examination time is shorter and patient comfort is improved. Use of a pitch of 2:1 permits a marked reduction in X-ray dose with no loss of image quality.