抄録
To examine the morphological changes of the mandibular alveolar ridge following mandibular ridge augmentation with artificial biological materials, serial rotational panoramic roentgenograms were analyzed using an X-ray image analyzing system.
Prior to the main experiment, the preliminary experiment using a head and neck phantom were performed to clarify the effect of head posture on the brightness of the X-ray images in this X-ray image analysis.
In the main experiment, 20 cases, 7 males and 13 females (average age of 66.7 years), underwent mandibular ridge augmentation with artificial biological materials and had a medical checkup at regular intervals up to 12 months after the operation.
The changes in area, length, height, and brightness of the mandibular alveolar ridge were evaluated quantitatively with the X-ray image analyzing system, and the results were as follows
1. The preliminary experiment demonstrated that the change of brightness in the X-ray images caused by the rotational change of head posture were significantly small, suggesting effective evaluation by the X-ray image analyzing system.
2. Although the area, length, and height of the augmented part of the alveolar ridge were reduced with the passage of time, their reduction ratio was small and long-term maintenance of the alveolar ridge shape after the insertion of dentures was suggested.
3. The brightness of the augmented alveolar ridge increases gradually, suggesting bone formation in this augmented portion.
4. In 13 cases with one-sided alveolar ridge formation, the area of the augmented part of the alveolar ridge correlated significantly with its height and length. In 7 cases with two-sided alveolar ridge formation, however, the area significantly correlated with its height only.
From the above results, there were few morphological changes in the augmented alveolar ridge with granular artificial biological materials, suggesting the long-term stability of the alveolar ridge shape and the clinical usefulness of this material.
