Polarized light microscopic analyses of collagen fibers in the rat incisor periodontal ligament in relation to areas, regions, and ages

Abstract

We prepared decalcified sagittal sections (20 m thick) from the incisal, middle, and basal regions of the mandibular incisor of male Wistar rats aged 2, 6, 12, and 24 months, and examined the sections using polarized light microscopy. Most of the birefringent fibers appeared to run obliquely across the periodontal ligament. Birefringent fibers running parallel to the long axis of the incisor were also found in the intermediate area of the ligament. Similar fiber architecture was observed in all four age groups. Quantitative analysis showed that the retardation values of collagen were higher in the bone-and tooth-related areas and lower in the intermediate area of the ligament. The values for the bone-and tooth-related areas increased from the basal toward the incisal regions in all four age groups. Age-related changes in the retardation values were found only in the incisal region of the incisor. In the incisal region, the values for the bone-and tooth-related areas increased markedly from 2-24 months of age, whereas those for the intermediate area increased slightly but significantly with age. Our findings indicate that the degrees of molecular organization and alignment of collagen fibers in the bone-and tooth-related areas of the ligament are higher than those in the intermediate area and increase near the incisal region and with age. It is also suggested that the collagen fibers in the intermediate area remain immature along the long axis of the incisor throughout the life span of the animal. Anat Rec 268: 381-387, 2002.

Polarization microscopy for characterizing fiber orientation of ocular tissues

“…PLM has been proven effective to characterize collagen of tendons [20,21], ligaments [22] and other soft tissues [23]. The possibility of using PLM in the cornea was discussed almost two decades ago for ex-vivo tissues [24], and more recently to study the cornea stroma in vivo [25].…”

Alveolar bone Sharpey fibers of the rat incisor in normal and altered functional conditions examined by scanning electron microscopy

“…The results herein described are in line with the observations by Chiba et al (1990) and Komatsu et al (1998), that the mechanical properties of the periodontal ligament of continuously erupting incisors increase in incisal direction. It was also shown in rat incisors that the molecular organization of periodontal ligament collagen fibers increases from basal to incisal (Komatsu et al, 2002).…”

Effect of Smoking on Attachment of Human Periodontal Ligament Cells to Periodontally Involved Root Surfaces Following Enamel Matrix Derivative Application

“…4) treated only with EMD, EMD was intensively adhered to the root surface in the form of granules of various sizes in accordance with the arrangement of collagen fibers. The direction of collagen fibers may have an affect on periodontal tissue resistance due to affecting the adhesiveness to root surface (22,34). Zhou et al (42) reported nicotine and P. gingivalis had an additive effect on human gingival fibroblast-mediated collagen degradation and these findings help to explain why smoking is a major factor contributing to the initiation and/or exacerbation of periodontal diseases.…”