The aim of this study was to determine
collagen density in the hypertrophic upper lip frenum and
scar forming after frenectomy and to compare the results with
collagen density in a normal population (autopsy specimens). Differences in
collagen density may cause problems in
diastema closure and may eventually result in relapse of this condition. The study was done in 47 patients treated for
diastema. Histomorphology was performed in 15 patients of this group. Autopsy material was obtained from 27 persons. Histomorphometric assessment of
collagen density was done after staining of
collagen fibers according to van Gieson. A computerized image analysis system was used for interactive detection of stained
collagen fibers on the digitized microscopic image. The percentage of positive staining expressed as ratio of positive area to whole area of the field studied was determined and recorded as an Excel file.
Collagen density was increased in the pathologic frenum and in the
scar as compared with the normal frenum. The difference was statistically significant.
Diastema treatment with frenectomy,
fixed appliance and retainer produced more stable results as compared to treatment with a removable appliance without frenectomy. The results suggest that the similar
collagen density observed in hypertrophic upper lip frenum and
scar after frenetomy may hinder complete closure of
diastema and facilitate relapse
after treatment.