CONFIRMED OSPE TOPICS Flashcards
list bacterial virulence factors
bacterial virulence factors = enable bacterial invasion and colonisation of periodontium
**bacteria characteristics
**- pili/fimbriae = adhesion/invasion
- capsule = protection against phagocytosis
- peptides = induces inflammation
**produced produced by bacteria **
- exotoxins = damage host immune cells
- enzymes = damage host proteins + acquire nutrients
OUTLINE THE TYPES OF DENTINE
primary
secondary
tertiary
describe primary dentine
- formed BEFORE to eruption - deposited at DEJ
- has incremental lines
- outer layer = mantle dentine [150um thick]
outer layer is divided into: [from outside to in]
- circumpulpal dentine
- globular dentine
- peritubular/intratubular dentine
- intERtubular dentine
describe secondary dentine
- formed AFTER completion of root formation and thoroughout tooth ageing process
- aka circumpulpal dentine
- scatters more slowly than primary
- causes canals to be smaller w age [deposition = decreased pulp chamber size]- - forms at roof and floor of roof chamber
describe tertiary dentine
forms if dentine experiences
- mechanical trauma
- irritation
- exposed hypersens dentin
- carious dentine
- traumatic cavity prep
reactionary
- forms in response to insult, damange sustained but **existing cells recover **
- formed by existing odontoblasts
reparative
- forms in response to insult, damage sustained –> original odontoblasts destroyed –> induces odontoblast precursors to differentiate and produce calcified tissue
describe general dentin properties
- forms BULK of tooth
- covered by enamel in the crown and cementum in the root
- consist of large number of small parallel tubules in mineralised collagen matrix [contains odontoblastic processes and dentinal fluids]
- harder than bone and cementum but softer than enamel
- by weight [inorganic 70%, organic 20%, water 10%]
outline the layers of dentine
crown
- mantle dentine
- interglobular dentin
- circumpulpal dentine [bulk] - covers pulpal space
[circumpulpal further div into:
- globular dentine
- peritubular/intratubular dentine
- intERtubular dentine
root
- hyaline layer
- granular layer of Tomes
- circumpulpal dentin [bulk]
i
briefly describe mantle dentine
deposited FIRST under DEJ in 150um wide band - mineralised by matrix vesicles
fibres perpendicular to DEJ
secreted by immature odontoblasts
briefly describe circumpulpal dentine
layer of dentine around outer pulpal wall - makes bulk of dentin in both crown + root
formed and matured after mantle dentine
briefly describe inter/globular dentine
between mantle and circumpulpal
beneath mantle dentine [crown] and grnular layer of tomes [root]
calcified following formation of matrix
becomes larger –> fuses as dentine develops - interglobular spaces present
briefly describe peritubular and intertubular dentin
peritubular dentin
- immediately surrounds dentinal tubule
- higher mineral content and LACKS collagenous matrix [more calcified and mineralised - less organic structure]
intertubular
- forms bulk of dentine around dentinal tubules of crown and root
- less mineralised
describe PDL
fibrous collagen CT between alveolar process and cementum
occupies periodontal space
contains
- fibroblasts, osteoblasts, cementoblasts
- blood cells
ground substance - 70% water w glycoproteins and proteoglycans
highly vasculuar + nerves
provides attachment of cementum to surrounding alveolar bone keeping the teeth resting in its socket - - acts as suspensory ligaments of teeth
- major func = permits tooth to withstand force of mastication
outline PDL organisation
group according to location
- gingival group
- around necks of tooth - support gingiva
- 1 alveologongival [free]
- 2 dentogingival [attached]
- 3 circular / circumferential fibres
- 4 dentalperiosteal - transeptal
- in between teeth
- cementum to cementum over alveolar crest
[func = resist rotational forces - holds teeth in interproximal contact] - dentoalveolar
- cementum to bone
- contains
alveolar crest group = resist tilting/rotation
horizontal group = resist tilting M/D/L/F / rotation
oblique group = resist inwards pushing and rotation
apical group = resist outward pull and rotation
interradicular group
outline oral mucosa classifications
lining mucosa
- found in areas which dont func in mastication
- softer surface texture, moist surface, ability to stretch/compress, cushions underlying structures
- eg soft palate, central surface of tongue, floor of mouth, alveolar mucosa, labial and bicca; mucosa
masticatory mucosa
- comes into primary contact w food during mastication
- covers immobile structures and firmly bound - well adapted to withstanding abrasion
- eg hard palate, free + attached gingiva
specialised mucosa
- assists in mastication + taste buds
lingual papillae
- foliate papillae - not well devel in humans
- filiform - ant 2/3 tongue
- fungiform - ant 2/3 tongue
- circumvalate - adjc//ant to terminalis sulcus
briefly describe the lamina propria
CT supporting oral epithelium
high vascularised capillary networks/loops
composed of TWO layers
1. papillary layer
- most superficial
- associated w rete ridges, collagen fibres and capillary loops
- reticular layer
- deeper layer
- dense conc of collagen arranged into bundles lying parallel to surface plane
list the layers of lining mucosa from superficial to deep
- superficial layer [flattened cells]
- intermediate layer
- basal layer [cuboidal above lamina propria]
- lamina propria [capillary loops + parallel bundles]
- submucosa
- muscle
list the layers of masticatory mucosa from superficial to deep
- keratin layer
- granular layer
- prockle layer
- basal layer [cuboidal cells above lamina propria]
- lamina propria [capillary loops + parallel bundles]
- minimal or absent submucosa
- bone
describe what happens in the pre eruptive phase
- movements related to tooth eruption occur PRIOR to crown formation [ant tooth germs move M and molars move D]
- movements facilitated by
bodily movment - mediated by bone remodelling of crypts - incl early initiation - finishes @ early root formation
describe what happens in the pre eruptive phase
- elongation/ development of root needs SPACE –> given by occlusal/incisal eruption
[allows root, dentin, cementum development]
axial/occlusal movement eruption pathway
- tissue removed by macrophages
- bone remodelled via osteoclasts
REE proliferates upwards, oral ectoderm proliferates downwards = cells fuse creating JE which attaches to developmental cuticle via hemidesmosomes
crown tip penetrates oral mucosa, causing stretching and thinning of mucosa = developmental cuticle remains
occlusal movement cont. until contact w opposing crown
more exposed crown shifts oral epithelium to cervical region
fine trabeculae form in fundic region, bone becomes denser when func occ reached
deciduous roots resorped to make way for permanent eruption sequence
debatable mechanisms
1. hammock ligamant theory [fibrous tx band at apex = root pushes against this]
2. bone remodelling theory
3. ligament traction theory
4. vasculuar pressure theory
describe what happens in the post eruptive/ func phase
occurs when teeth reach func occ and continues as long as teeth are present
during process of root completion - alveolar height increases
fundic alveolar plates resorp to accomodate formation of root tip apex
marked changes
- ^ bone mineral density
- ^ density and orientation in PDL
THREE catergories
1. accomodation of growth
- occurs 14-18, completes towards 20yo
- socket readjustments from new bone deposition
- compensation of occlusal wear
- continued cementum deposition [only after teeth move] - accomodation for interproximal wear
- at contact points
- M drifting accomodtes for interproximal wear
- up to 7mm in mandible
distinguish between major and minor glands
major
- carry secretion through longer main duct into oral cavity
- parotid, submandibular, sublingual
- inactive during sleep
minor
- empty sec. via short ducts
- separated small glands throughout mouth
- active all the time
- mostly mucous w/ some serous influence
BOTH = compose of epithelium + CT
epithelium = lines duct system and produces saliva
CT = surrounds epithelium - protecting tissue + supporting gland
distinguish between the two secretory cell types
serous = high protein low carbohydrate
mucous= low protein high carbohydrate
- most minor salivary glands –> mostly mucous cells
outline the structure of salivary glands
stroma [supportive CT]
- septa [carries blood and nerve –> parenchyme]
- blood vessels and nerves
- ducts
- lobules
parenchyma [glandular secretory tissue]
- accini [func unit of salivary gland]
- duct system
describe the parenchymal structure of major salivary glands
parotid
- largest gland
- 25% of total salivary volume
- parotid duct/Stenson’s duct opens –> parotid papilla
- mainly serous
submandibular
- 2nd largest
- 60-65% total salivary vol
- travels through Wharton’s duct –>opens into oral cavity –> sublingual caruncle
- both serous and mucous products
sublingual
- smallest
- 10% total salivary vol
- travels through Bartholin’s duct –> open into oral cavity –> sublingual caruncle
- mainly mucous
briefly describe the TMJ
TMJ - temporomandibular joint
- compound synovial joint on each side of head - connects mandible –> temporal bone
- allows for mastication, speech, respiratory movement
- most complex set of joint in body
- allows mandibular condolytes to move in gliding and hinging actions
outline the anatomical structure of the TMJ
upper
- articular eminence [top hump in bone]
- anterior part of glenoid fossa [socket]
- articular disc aka meniscus [fibrous disc div TMJ into upper/lower parts]
lower
- condyle head of mandible [pivot in joint which lower jaw swings
state bacteria classification groups
- gram staining [positive / negative]
- cell morphology
- cocci [spherical]
- bacilli [rectangular]
- spirilla [curved/spiral shape] - motile vs non motile
- relationship w oxygen to sustain life
- aerobes
- anaerobes
state biofilm formation steps
- ACQUIRED PELLICLE FORMATION
- mins after enamel is cleansed –> film [acquired pellicle] of salivary glycoproteins and antibodies forms over tooth surface
- pellicle facilitates bacterial adhesion - ASSOCIATION // ADHESION
- association = within few hrs after pellicle formation, bacteria associates loosely w acquired pellicle
- adhesion = early colonisers - non pathogenic bacteria bind to pellicle
- streptococcus species - COAGGREGATION AND MULTIPLATION
- coaggregation of SECONDARY colonisers [bacteria have specific coaggregation partners - biofilm develops
- multiplication = attached micro-organisms multiple - MICROCOLONY FORMATION
- attachment of FUSOBACTERIUM NUCLEATEUM [g-neg rod] to biofilm and bridges the early coloniser with late colonisers [more g-neg yet to come]
- extracellular polysaccharide [EPS] matrix = sec layer that surrounds microcolonies = acts as protective barrier from antibiotics, immune system
- - EPS matrix also provides reserve of carbs, aids adherence and acts as diffusion barrier - MATURATION + DISPERSAL
- bacteria proliferate away from tooth –> create mushroom shaped colonies attached to tooth by NARROW base
- periodontal pathogens begin to coaggregate
list 3 cariogenic bacteria species
lactobacilli
Streptococcus mutans
Streptococcus sobrinus
all are g-pos anaerobes
list five periodontal pathogen species
red socransky’s complex
treponema denticola
porphyromonas gingivalis
tannerella forsythia
orange socransky’s complex
fusobacterium nucleateum
prevotella intermedia
what do the colours in Socranky’s Complexes indicate
yellow/green = early colonisers - compatible w gingival health
orange/red = major etiologic agents of periodontal disease
benefits of bacteria living in supragingival vs subgingival environment
supragingival
- available nutrients [dietary carbohydrates]
- other bacteria species present
- salivary glycoproteins
subgingival
- little to no saliva
- pH fairly consistent
- available nutrients [serum proteins]
describe amalgam composition
silver alloy powder [silver, copper, tin] mixed with mercury [mixing reaction = amalgamation]
one of the oldest direct resto materials
high copper amalgams = higher strength, less corrosion, less creep, better longevity at margins
outline amalgam classification
particle composition
- copper / zinc content
particle shape
- alloy particle geometry and size
- spherical, irregular [lathe cut], admixed
- irregular [provides more resistance to packing but very strong]
- spherical [more easily condensed - req less mercury]
most popular = admixed high copper amalgam
outline amalgam chemistry
reaction between silver alloy and mercury = amalgamation
- when reaction complete, little-no mercury left unreacted
when high copper alloy particles contact mercy, the copper, silver, tin –> dissolve into mercury
- new solid products begin to crystallise until they harden completely
set amalgam contains unchanged particle cores consisting of gamma phase [Y] surrounded by matrix of gamma 1 Y1 and gamma 2 Y2
- gamma 2 Y2 = ^ corrosion, creep and lower strength
- modern amalgam has higher copper = less gamma 2Y2
what is the composition of admixed high copper amalgam
silver 69%
tin 17%
copper 13%
zinc 1%
what is dimensional change in amalgam
in freshly mixed amalgam :
contraction = negative dimensional change
- may cause gaps in restoration - tooth prone to leakge and recurrent decay
expansion = positive dimensional change
- may cause post of sens or protrusion from cavity
what is creep in amalgam
repeated mastication = creep
- margin breakdown as the thin margins gradually stretch out and fracture causing ditches at margins
differentiate tarnish from corrosion in amalgam
tarnish = discolouration of restoration
- lack of lustre
- chemical reaction restricted to amalgam surface
- will NOT cause restoration failure
corrosion
- chemical reactions which penetrate amalgam body
- eventually leads to restoration failure
BOTH occur on rough surfaces = having a smooth amalgam limits these problems
indications vs contraindications for amalgam restorations
indications
- large restos in perm premolars + molars
- areas of high masticatory forces - due to durability and strength
- moisture tolerant - can be used in difficult moisture isolation situations
contraindications
- not for use in deciduous dentition
- not for anterior teeth where aesthetics important
- small class I and II restorations where moisture isolation possible
describe GIC for restorations
water-based cement formed by acid/base reaction
- polyalkenoic acid // base of ion-leachable, fluoride containing, calcium, strontium or strontium aluminosilicate glass
- does not have compressive strength of amalgam
- does not have flexural strength or aesthetics of CR
outline GIC properties
biocompatibility
- biological potential [calcium, fluoride ions able to diffuse in and out of material = remin]
- resistant to plaque
- fluoride release
- pulp response to GIC [resolves inflammation]
**solubility and dinsintegration
**- dimensional change
- resistance to fracture
- abrasion resistance
list GIC indications and contraindications
indications
- restorative [deciduous, perm class III and V where aesthetics not important, ART techniques, root caries]
- temps
- fissue protections
- lining/base
- luting cements
contraindications
- class IV fractures
- large areas of labial surfaces where aesthetics important
- class II where conventional cavity prepped
- lost cusps
- under full crown or PFM
- in areas subject to higher occlusal loading
