Chapter 1 Flashcards
what are the 3 types of oral mucosa and where are they found
- masticatory mucosa: gingiva, hard palate
- lining mucosa: alveolar mucosa, floor of the mouth
- specialized mucosa: dorsal of tongue
what are the 2 landmarks of masticatory mucosa
- coronal: gingival margin
- apical: mucogingival junction
what are the 3 parts of the gingiva
- free (marginal) gingiva
- interdental gingiva
- attached gingiva
what is free gingiva
- surrounds the neck of the tooth
- coronal: gingival margin
- apical: free gingival groove
- smooth surface: lightly stippled
- entry into gingival crevice/sulcus
what is the gingival crevice
- space between tooth and gingiva
- coronal: gingival margin
- lateral: tooth and epithelium
- apical: junctional epithelium
what is gingival crevicular fluid
- found in the sulcus
- fluid from blood vessels
- fluid resembles serum
- flow dependent on inflammation
- how much in there depends on what is present for bacteria
what is attached gingiva
- begins at the free gingival groove
- apical: MGJ
- width varies
- not movable tissue
- stippling
how can you find the total width of gingiva
- free gingiva + attached gingiva
how can you find the zone of attached gingiva (ZAG)
- free gingiva + attached gingiva - probing depth
what is interdental papillae
- extension of free gingiva
- shape:
- pyramidal: anterior
- more flat: posterior
- COL: concave, less keratinization
what is alveolar mucosa
- coronal: MGJ
- thin, red
- no stippling
- moveable: elastic fibers
what are frenums
- folds of alveolar mucosa
- attach lips and cheeks to mx/mn alveolar mucosa
- 7 in total
- originate and end in alveolar mucosa
what are the components of gingiva
- stratified squamous epithelium
- avascular, no nerves
- keratinized to protect from abrasion and keep hydrated from dehydration of glycolipids produced in the stratum granulosum (ie masticatory mucosa)
- non keratinized surfaces must be kept moist by bodily secretions to prevent them from drying out (ie lining mucosa of oral cavity, inside portions of the lips)
- connective tissue (lamina propria), vascular, nerves, underneath
what 3 structures is the gingival epithelium divided into
- oral epithelium: visible in smiling
- sulcular epithelium: in sulcus
- junctional epithelium: base of sulcus
why does the gingival epithelium appear stippling
- fingerlike projections termed connective tissue papillae extend into the depression on the undersurface of the epithelium. this produces the characteristic stippled appearance of the attached gingiva
what are the 4 layers of stratified squamous
- basal layer (stratum germinativum)
- prickle cell layer (stratum spinosum)
- granular cell layer( stratum granulosum)
- keratinized cell layer (stratum corneum)
what is the process of keratinization/cell renewal
- differentiation of cells
- start at basal layer - cell division
- cell becomes keratinocyte in prickle layer
- keratin produced as it reached s. corneum
what is keratin
- protein
- mechanical toughness
- keratinocytes slowly shed once reach outer epithelial surface
- process continues and speed depends on trauma to tissue
what are the layers of stratified squamous epithelium from coronal to apical
- stratum corneum
- stratum granulosum
- stratum spinosum
- basal layer
- all of these make up the oral epithelium*
- alveolar bone
what is parakeratinized
- mouth, masticatory mucosa
- basal, prickle, granular, keratinized area on top
- no stratum corneum as cells maintain nucleus
what type of cells make up oral epithelium
- keratinized and/or parakeratinized stratus squamous (10 day turnover on cells)
- keratinocytes (make up majority of cells)
- melanocytes (in basal layer associated with nerve endings/sensory)
- langerhans (in stratum spinosum - defense)
- merkel - (in basal layer associated with nerve endings/sensory)
what is the purpose of the cells in the oral epithelium
- protective purpose: mechanical toughness
- cell renewal: 10 day turnover
what is sulcular epithelium
- lines the sulcus
- thin, non to para keratinized
- much less than oral epithelium
- coronal: crest of gingival margin
- apical: coronal junctional epithelium
what is junctional epithelium
- thin, non keratinized
- continuous with sulcular epithelium
- attaches gingiva to tooth
- role in periodontal disease
- coronal: apical portion of sulcular epithelium
- apical: CEJ (in health) is just below
- semipermeable membrane: wide intercellular spaces; allow passage of fluids, bacteria (toxins); more permeable toward sulcular epithelium
what cells are found in the junctional epithelium
- neutrophils (PMN)
- in sulcus, pass through the junctional epithelium
- defense mechanism
- lateral: tooth or lamina propria (connective tissue)
how do we calculate CAL when the gingival margin is above the CEJ
- pocket depth - the gingival margin to CEJ measurement = CAL
how do we calculate CAL when the gingival margin is at the CEJ
- probing depth = CAL
how do we calculate CAL when the gingival margin is below the CEJ (recession)
- recession + pocket depth = CAL
how long does it take for the cells at the junctional epithelium to regenerate
- 4-7 days (cells regenerate fastest)
how long does it take for the cells of the oral epithelium and sulcular epithelium to regenerate
- 10 days
how long does it take for the cells of the palate, tongue and cheek to regenerate
- 5-6 days
what is alveolar mucosa epithelium like
- non-keratinized
- very elastic
- very vascular
what are the different types of gingival fibres
- circular (only found in free gingiva)
- dentogingival (most important)
- dentoperiosteal
- transseptal
- alveologingival - gingiva to bone
what is the overall function of gingival fibres
- to give contour and firm connection to tooth and bone
see slide 68
see slide 68
what does the lamina propria consist of
- cells, vessels, nerves
- collagen fibers (60%)
what produces ground substance in the lamina propria
- fibroblasts including collagen and collagenase, which helps break down the periodontium
what cells make up the lamina propria
- fibroblasts, mast cells, PMNs
- macrophages (pacmans), lymphocytes, plasma cells
how are epithelial cells held together
- desmosomes: holds the cells together like glue guns
- intercellular bridges between epithelial cells (holds epithelial cells together)
- allows some passage of materials (semi permeable)
why does the base of the sulcus (junctional epithelium) have 4x few desmosomes
- this creates a more permeable tissue - this is so that all the fighting micro-organisms can pass back up into the sulcus from below to fight bacteria and help heal
the basal lamina is a combination of what two layers
- the basal densa and basal lucida
what is a hemidesmosome
- half a desmosome
- basal lamina = (lamina lucida and lamina densa)
what are anchoring fibrils
- on connective tissue side of epithelial cells
- anchor epithelial cells to connective tissue
what is the dentogingival unit
- JE + gingival fibrils
- (JE is the epithelial attachment and the gingival fibres are the connective tissue attachment/cementum)
what is biological width
- JE + gingival fibers at the base of the sulcus
- combined length of the unit; must be at least 2.04 mm to put a crown on the tooth
how do we get a combined length of 2.04 mm
- connective tissue attachment 1.07 mm + junctional epithelium 0.97 mm = 2.04 mm total (call it 2mm)
see slide 80
see slide 80
what is biological width
- the space between the junctional epithelium (base of the sulcus) to the alveolar bone
what can occur when the biological width is disturbed
- bone loss or inflammation
what is the attachment apparatus
- PDL
- cementum
- alveolar bone
what do fibroblasts make in the PDL
- collagen
what do cementoblasts make in the PDL
- cementum, located on the cementum side
what do osteoblasts make in the PDL
- bone, located on the bone side
what is the width of the periodontal ligament
- 0.25 mm
what are sharper’s fibers
- embedded into the cementum and bone on any ligament that goes from bone to cementum
what are the 5 types of periodontal ligament fibers
- alveolar crest
- horizontal
- oblique
- apical
- interradicular
what are the 6 main functions of the periodontal ligament fibers
- suspensory
- shock absorber
- remodelling
- blood supply
- tactile pressure - sensory - pain/pressure
- proprioceptive (sense of position)
what is the function of cementum
- connective tissue
- attaches the principal fibers to the tooth
what are the 2 types of cementum
- acellular: forms before the tooth erupts, contains no cells, coronal two thirds, thinnest at the CEJ
- cellular: apical one third, formed faster than acellular, lay down additional cementum, maintain vertical dimension of root due to attrition
features of cementum
- cellular is deposited continuously
- avascular
- does not resorb like bone
- hypercementosis
what are the 2 parts of the alveolar process
- alveolar bone proper
2. supporting bone
what is the alveolar bone proper
- also called the cribriform plate (lines the socket)
- hard cortical bone
- lamina dura (radiographically)
- bundle bone is inner surface which receives sharper’s fibers
what is the supporting bone
- either compact cortical plates (covers the alveolar process = buccal and lingual plates) or spongy/cancellous/trabecular bone (between buccal and lingual plates)
what is the alveolar crest
- cortical plates fuse
- no spongy bone
- shape continuous with interdental space
- usually 2 mm below the CEJ in health
what is the shape of the alveolar bone crest influenced by
- width of the interdental space
- stage of eruption
- position of the teeth in the arch
- shape of the cementoenamel junction
how is blood supplied to the periodontium
- vessels of the periosteum (supraperiosteal)
- periodontal ligament
- alveolar bone
how does the periodontium change with aging
- thinning gingiva
- reduced keratin
- cementum increases
- bone drifting - mesial
- attrition
