Radiographic defect depth and width for prognosis and description of periodontal healing of infrabony defects

Aim of the study

To evaluate the effect of the dimensions of intrabony defects on their potential for regeneration and to measure the reduction in size of bony lesions after guided tissue regeneration.

Materials and methods

Twenty-four patients suffering from advanced periodontitis were included in the study. Thirty-nine lesions were treated with the use of membranes (7 defects with non-resorbable and 32 with resorbable). Twelve patients presented with one defect, ten with two and one subject with three lesions to be treated. The lesions involved all types of teeth except maxillary molars. Clinical and radiographic assessments were under taken. Bitewing radiographs were taken at the beginning and at 6 and 24 months. After digitisation of the data, the results were analysed by computer.

Results

The plaque index remained low throughout the study (0.4 at 24 months). The initial mean depth of the defects was 3.87 ± 2.17 mm. The mean gain of attachment at 24 months was 3.31 ± 1.65 mm, the mean gain of bone vertically 1.54 ± 2.7 mm and the reduction in width of the defects was 1.17 ± 1.5 mm. The size and depth of the lesions had no significant effect on the gain of attachment, although there was more bone regeneration in the deep (> 3 mm) and narrow (< 26°) defects. Following regression analysis, it was shown that the initial level of attachment had a positive effect on the gain of attachment and that the initial depth strongly influenced the amount of bone formation.

Conclusion-commentary

This study confirmed that the angle of the bone defect affects the prognosis for guided tissue regeneration. Bone lesions of < 26° have three times as much bone formation after 2 years compared with lesions > 26°. However, these results show a large standard deviation that reveal a weak predictability of results. The small number of patients in this study should also be taken in to consideration.