Oblique lateral cephalometric radiographs of the mandible in implantology:usefulness and accuracy of the technique in height measurements of mandibular bone in vivo

Various radiographic techniques are used for longitudinal studies of change s in the height of the mandible with implants. Advantages and disadvantages of panoramic radiographs, lateral cephalometric radiographs, periapical fi lms and modern CT- and MRI-techniques are briefly discussed. In this study, the usefulness of a conventional radiographic technique for measuring the height of the mandible, i.e. oblique lateral cephalometric radiography (OLC R) is evaluated in viva. In 16 patients with permucosal implants in the ant erior mandible OLCRs were repeated the same day. The mean total error for t he radiographic procedure and analysis was 0.38 mm. The intra-observer erro r for the determination of the mandibular height by means of the image anal ysis procedure was 0.16 mm (analysis error). In 12 other patients pairs of radiographs of the same area of the mandible were made using both a "standa rd" horizontal X-ray beam direction and an individually determined "optimal " horizontal X-ray beam direction; the maximum difference between these two angulations was plus or minus 7.5 degrees. The effect of this different an gulation on the height measurements is comparable to the above-mentioned to tal error of the measurement procedure (positioning error). An accurate pos itioning of the patient seems important for reliable measurements. The desc ribed radiographic (OLCR) and analysis (IBAS) technique can be used relativ ely simply for clinical studies. The described methods appear to be useful for measuring the mandibular height in longitudinal studies in patients wit h or without implants.