821. The attached apparatus of tooth is composed of______________?
A. Gingiva, cementum and alveolar bone
B. Gingiva and cementum
C. Cementum and periodontal ligament
D. Periodontal ligament the cementum and the alveolar bone

822. Age changes in periodontal ligament include which of the following ?
A. Increased fibroplasia
B. Increased vascularity
C. Increased thickness
D. Decreased in number of cementicles

823. Collagen molecule exhibits all of the following features except_____________?

A. Triple pleated sheath
B. Mostly contains glycine residues
C. Exhibit cross striations at 64 μm
D. Intracellular in nature

824. Which of the following is not the principle fibre group of the periodontal ligament___________?
A. Horizontal
B. Oblique
C. Alveolar crest
D. Transseplat

825. A special feature of the periodontal ligament fibroblasts is______________?
A. The number or organelles
B. Presence of actin fibres and shape change
C. size of the cells
D. Collagen fibre formation

826. The component of future T.M.J shows development at _____________?
A. 6 weeks
B. 10 weeks
C. 18 weeks
D. 16 weeks

827. The periodontal ligament is approximately_____________?
A. 0.25 mm in thickness
B. 0.5 mm in thickness
C. 0.75 mm in thickness
D. mm in thickness

828. Development of supporting tissues of the tooth is initiated by____________?
A. Cells of dental follicle
B. Cells of odontogenic layer
C. Cementoblasts
D. Cells of the gingiva

829. Width of the periodontal ligament is least at______________?
A. Cervical third
B. Apical third
C. Fulcrum of rotation
D. It has uniform width

830. Cementicles are found in the_____________?
A. Gingiva
B. Periodontal ligament
C. Alveolar bone
D. Cementum