What type of Fibres are principal Fibres of PDL?

The PDL consists of principal fibers, loose connective tissue, blast and clast cells, oxytalan fibers and Cell Rest of Malassez. The primary principal fiber group is the alveolodental ligament, which consists of five different fiber subgroups.

What are the PDL fibers?

The periodontal ligament, commonly abbreviated as the PDL, is a group of specialized connective tissue fibers that essentially attach a tooth to the alveolar bone within which it sits. It inserts into root cementum one side and onto alveolar bone on the other.

What is the function of PDL?

Structure of the Oral Tissues The PDL is a highly specialized connective tissue situated between the tooth and the alveolar bone (Figure 1-5). The principal function of the PDL is to connect the tooth to the jaw, which it must do in such a way that the tooth will withstand the considerable forces of mastication.

Which PDL fibers are most numerous?

Horizontal fibres run perpendicularly to the long axis of the tooth, from cementum to alveolar bone, covering the apical two-thirds of the root. Oblique fibres are the most abundant fibre group in the PDL, extending from the cementum in a coronal direction obliquely to the alveolar bone.

What is PDL widening?

PDL widening, thickening of the lamina dura, increased number and size of trabeculae and bone loss are radiographic features. Continuous force causes tooth movement that is marked initially by PDL narrowing. In the secondary period of tooth movement, the PDL is considerably widened.

What is the alveolar crest group?

The alveolar crest is the most coronal portion, or the top, of the alveolar process. It is an extension of both the mandible and maxilla and holds the tooth sockets. The alveolar crest is often the first portion of the alveolar process that is damaged by periodontal disease and is therefore the first bone that is lost.

What causes widening of PDL?

PDL widening occurs in trauma from occlusion, but in association with angular bone defects and mobility of teeth. However, in scleroderma, involved teeth are often not mobile and their gingival attachments are usually intact.

What causes thickening of lamina dura?

Bone changes may take the appearance of thickening of the lamina dura, widening of the periodontal ligament, focal sclerosis, cortical erosion and radiolucent areas (Table. 1), but these are nonspecific and can occur because of ‘everyday’ dental disease and even normal anatomical variation in bone pattern.

What is PDL in dentistry?

Introduction. The periodontal ligament, commonly known as the PDL, is a soft connective tissue between the inner wall of the alveolar socket and the roots of the teeth. It consists of collagen bands (mostly type I collagen) connecting the cementum of teeth to the gingivae and alveolar bone.

What type of collagen is in PDL?

The major component of PDL is fibrillar collagens including types I, III and V, accounting for ~75%, 20% and 5% of collagens, respectively [36,37]. In addition to the fibrillar collagens, non-fibrillar collagens such as types IV, VI, XII and XIV are also present as minor components in PDL [38,39] (Table 1).

What does widening of PDL mean?

A vertical bone defect develops when bone loss progresses down the root of the teeth in association with a deep periodontal pocket. In its early stage, this phenomenon appears as abnormal PDL widening (Fig. 3).

Which is the principal fiber group of the PDL?

The PDL consists of principal fibers, loose connective tissue, blast and clast cells, oxytalan fibers and Cell Rest of Malassez. The primary principal fiber group is the alveolodental ligament, which consists of five different fiber subgroups.

What kind of collagen is in the periodontal ligament?

The PDL matrix consists of collagen (collagen types of similar proportion to that of gingiva above) in an amorphous proteoglycan matrix. The principal fibers of the periodontal ligament are of type I collagen and are inserted into both the alveolar bone and cementum of the tooth.

How are oxytalan fibers unique to the PDL?

Oxytalan fibers are unique to PDL and are naturally elastic. It inserts into the cementum and runs in two different directions; parallel to the root surface and oblique to the root surface. The PDL substance is estimated to contain up to 70% water. It is thought to have a significant effect on the tooth’s strength and ability to withstand stress.

How does the thickness of the PDL relate to function?

The thickness of the ligament relates to the degree of function because the PDL is thinnest around the roots of embedded teeth and teeth that have lost their antagonists. The reverse is not true, however, because an appreciably wider space is not regularly observed in persons with especially heavy occlusion or bruxism.