PRINCIPLE GROUP OF PDL FIBRES:

a) Alveolocrestal fibres – prevents extrusion of teeth
b) Horizontal fibres – prevents lateral movement of teeth
c) Oblique fibres – withstands masticatory forces, most abundant
QN. Periodontal ligament fibers in middle third of root is oblique.
d) Apical fibres – absent in young permanent teeth , because of open apex
e) Intraradicular fibres – absent in single rooted teeth
TRANSEPTAL FIBRES
 Transseptal fibers are Fibers which completely embedded in cementation and pass from cementation of one tooth to the cementation of adjacent tooth.
 the only fibers present in cementum only
 Not a pdl group of fibres
 Responsible for orthodontic relapse
 This fibre is removed in pericision(surgical Rx to prevent ortho relapse)
 Dentogingival fibre — the 1st fibre lost during extraction
 In pulp :- - Cell rich zone inner most pulp layer contain fibroblast
 – Cell free zone rich in capillaries & nerve networks
 - Odontoblastic layer contain odontoblast.