19. Functions and ageing of the periodontium.

FUNCTIONS AND AGING OF PERIODONTIUM

FUNCTIONS OF PERIODONTIUM

• Formative
• Periodontal ligaments are in continuous modelling and remodelling which is supported by fibroblasts, macrophages and undifferentiated mesenchymal cells
• Supportive -> fixes tooth in alveoli
• Essential function of periodontal ligaments is to attach the tooth root to the alveoli and maintain it throughout its life
• Provides complex tooth movements during chewing acts and protects tissue from chewing forces
• Amy mistake in this function results in tooth loss
• Sensory propioceptors in terminal ends of nerves sense chewing forces -> regulates chewing pressure!
• Abundant PDL receptors capture pressure and nerves send signals to the brain
• Forms the chewing apparatus of determining the strength and mode of chewing
• Such signals are sent to the maxillary joint and chewing muscles
• Ligamentum circularae: transverse forces
• Ligamentum oblique: axial forces
• Ligamentum longitudinale: expulsive forces
• Nutritive -> nourishes cementum, periodontium, alveolar bone
• Blood supply provides the periodontal ligaments with the necessary products to perform their functions
• It nourishes its structures, the cement, the surface of alveolar bone. Feeds on all cellular elements
• Aids Tooth Movement
• When forces are exerted on tooth, ligaments are under pressure and blood vessels are composed interruption of blood flow
• Results in interruption of some of them and insufficient nutrition of the plot. Cells shrink and ischemia occurs
• Tissue becomes transparent and is described as hyalinized
• Longer acting pressures result in osteoclasts and loss of alveolar bone. It creates a space where the tooth root can move and new blood vessels sprout
• Protective – protects from overload -> cement + alveolar bone + is a boundary for MOs Saliva
• It protects its elements and fibre as well as cement and alveolar bone from overload
• Protects periodontium from invading external elemtns and agents via saliva and other MOs
• Recovery
• Healing function of damaged structures is provided
• Done by contacting the cells with the surrounding intercellular fluid
• This is how they respond to diability and are stimulated to recover
• Fibroblasts, together with newly formed fibres are the emergency brigade of the periodontium with damaged fibres
• They repair in situ, but also, protect the cemtn and alveolar bone from damage

Ageing of Periodontium

1. (1) Age changes in gingival epithelium -> thinning & decreased keratinization!

• Thinning and decreased keratinization of gingival epithelium due to increase in epithelial permeability to bacterial antigens, decreased resistance to functional trauma or both

(2) Changes in gingival connective tissue tougher, harder? → less elastic