Oral Biology Flashcards
What cells form enamel?
Ameloblasts
What cells form dentine?
Odontoblasts
How does dentine differ from enamel?
- dentine is permeable
- softer than enamel
- greater compressive & tensile strength compared with enamel
What is dentine composed of?
- hydroxyapetite (50%)
- water (20%)
- organic matrix (30%)
How does the structure of dentine determine caries progression?
Caries progresses along dentinal tubules
What is predentine?
unmineralised dentine that is formed by odontoblasts during tooth formation
What type of tissue is dental pulp? What cells are found within it?
connective tissue
- odontoblasts
- fibroblasts
- defence cells
What are the functions of the dental pulp?
- nutritive
- dentine growth
- dentine repair
- defence
What is the function of cementum?
provides attachment for periodontal fibres
What are the different types of cementum?
ACELLULAR
- no cells
- adjacent to dentine
- formed first
CELLULAR
- contains cementocytes
- formed later
Where is acellular cementum located?
adjacent to dentine & more coronally
Where is cellular cementum located?
apical part of root and furcation regions
What nerves are found in the periodontal ligament & state their function?
Mechanoreceptors = evaluates how much force is being applied to PDL
Nociceptors = their function is to look for dangerous/harmful stimuli
What function does the PDL have?
- attaches tooth to bone
- transmits biting forces to alveolar bone
What width is the PDL approx?
0.2mm
What are the cell layers of epithelium?
- stratum corneum
- stratum granulosum
- stratum spinosum
- stratum germinativum (basal layer)
What type of mucosa is located on dorsum of tongue?
(keratinsised) gustatory mucosa
What protective functions do oral fluids have?
- cleansing
- mucosal protection
- buffering
- remineralisation
- antimicrobial
What can a reduction in salivary flow promote?
Increased incidence of:
- caries
- stomatitis
- dysaesthesia
- impaired oral function
- diminished taste perception
What type of secretions are from submandibular gland?
mucous secretions
What type of secretions are from sublingual gland?
mixed serous & mucous secretions
What type of secretions are from parotid gland?
serous secretions
what type of secretions occur from minor salivary glands?
mostly mucous
What do histatins inhibit?
candida albicans & streptococcus mutans
Describe mechanical salivary stimulation:
pressure on PDL –> increases flow from ipsilateral salivary glands (same side chewing on)
What are examples of PDL fibres?
Sharpey’s fibres
What is shown on the Stephan Curve?
A graph of the plaque pH change over time as plaque micro-organisms generate acid by metabolising sugars (eg sucrose)
