Dental pathology (practicals) Flashcards
what does the periodontium comprise?
gingivae, periodontal ligament, cementum and alveolar bone
what does H&E stand for?
Haemotoxylin and eosin
used to stain biopsy material
what colour does the haemotoxylin stain and what does it stain?
acidic stuff stains blue
what colour does the eosin stain and what does it stain?
proteins stain pink
what are the 5 signs of inflammation?
redness, swelling, loss of function, pain, heat
what does plaque cause the gingiva to do?
plaque causes a loss of hemidesmosomal attachment so loss of adhesion, allowing bacteria into the anaerobic environment. elicits an immune response.
what does ulceration allow?
allows bacteria to enter the body
what is the difference between inflammation and infection?
inflammation is the body response to tissue damage
infection is the presence of pathogenic organisms in the tissue
when can you have infection without inflammation?
immuno-suppressed individuals and HIV
what are the main cells from acute inflammation and what colour do they stain?
PMNs = neutrophils (not stained much), basophils (blue), eosinophils (pink)
what do neutrophils do in the immune response?
degranulate and digest parts of tissues.
what happens when there is an accumulation of neutrophils?
pus = an accumulation of neutrophils, and therefore an abcess
what happens if an abscess is not drained?
if not drained, it becomes chronic inflammation
what cells are involved in chronic inflammation?
macrophages, plasma cells, lymphocytes
why does hyperplasia occur from plaque getting into the pockets?
inflammatory process sends signals telling cells to reproduce. oedema occurs due to leakage of capillaries.
what is ulceration?
lack of epithelium, exposure
why might a pocket look larger than it is upon probing?
depth might not look too large, but plaque causes oedema and inflammation, appearing larger
what membrane is found on both sides of the epithelial attachment of gingiva?
basement membrane
what occurs on the tooth side of the gingiva?
continued deposition of basement membrane material allows maintenance or reformation of the attachment, even in the face of disease or therapy that temporarily destroys it
what do principle collagen fibres of the PDL attach to bone cementum by?
Sharpey’s fibres
what is a feature of Sharpey’s fibres?
they show high rates of turnover, allowing tooth movement (both intra-socket and translocatory)
are elastic fibres found in the gingiva?
no, function might be performed by oxytalan
what is the purpose of rete pegs and dermal papilla, found in the gingiva stratefied epithelium?
increase surface area for attachment
increase adhesion of epithelium to tissue
has interdigitations
how do we know when the crown starts on a histological section?
crown starts when the cementum stops
what is it when the stain is kinda brown?
plaque and calculus
what is a suprabony pocket?
horizontal bone loss
when the deepest part of the pocket is coronal (above) the bone crest
what are the walls made of in suprabony pockets?
one is soft tissue (gingiva) and one is the tooth
what is a infrabony pocket?
vertical bone loss
the deepest part of the pocket is apical to the bone crest. probe goes deeper than the top of the bone crest. can go between PDL.
what are the walls of infrabony pockets?
both hard tissues, one is bone, one is tooth
if maxillary sinus is seen, which area of the mouth is the section taken?
the maxilla
upper molars usually
if the lesion reaches the furcation, what treatment should occur?
open a gingival flap and clean the furcation. brushes to clean it. RCT followed by hemisection, remove 1 root and crown it. long winded.
otherwise extraction
if there is a very large gingiva, an overgrowth, but not due to plaque, what is the cause?
might be a systemic enlargement not localised
medicines e.g., cyclosporin for transplant patients
reduce immune system allows plaque to cause a larger response
in a carious lesion, what disappears in the body of the lesion?
stria of Retzus diappear
what is a ground section?
a histological section without chemical use for preparation of sample
process of obtaining a ground section?
cut enamel with a diamond disc and polish it with diamond paste and it gets smaller. when it is almost transparent, put it under a microscope.
why are the different colours/shades in a ground section?
dark and translucent lines due to how the light passes through/refracts after passing through the enamel
amount of porosity in enamel changes the refraction amount of the light
why is ground section used for enamel?
enamel is made of 96% inorganic hydroxyapatitie crystals which would dissolve if a demineralised section was used
why is the superficial zone of the lesion less destroyed by plaque than the body of the lesion?
superficial zone has more minerals and less pores than body of the lesion
is prismatic in some areas, so more resistant to acid and plaque, so acid cannot penetrate layer as much as disorganised layer below
exposure to saliva so buffering capacity and ions protects it from acid
fluoride exposure also protects
if there was a second translucent zone, where would it be?
between the body of the lesion and the dark zone
what are dead tracts of fish?
tubules that are blocked because theyre filled with fluid
tubules have a different refraction index thus appear darker
what happens if a carious lesion is untreated?
it keeps growing and will reach the ADJ, spreading laterally because dentine is not mineralised and more porous than enamel, thus easier for enamel to be eroded first
cavity will also keep retaining plaque
what is sclerotic dentine?
less porous peritubular dentine which is narrower
or mineralisation of the odontoblastic process
what is the dentine like in older people?
they have narrower dental tubules, so more sclerotic dentine and thus looks more translucent
what breaks down the organic and inorganic material in teeth?
proteolysis breakdown organic material
acidogenic bacteria breaks down inorganic material
is there bacteria in the zone of demineralisation?
no
it occurs deeper than the pioneer bacteria because the acid can diffuse further than the bacteria, but acid is still able to break down dentine
what are the 4 zones of dentine lesion?
zone of destruction, bacterial invasion, demineralisation, sclerosis
how does the appearance of the infected tubules vary as one moves from the advancing edge of the lesion to the ADJ?
at the advancing edge, the infected tubules appear widened and discoloured due to the presence of bacteria, debris and minerals.
at the affected dentine zone, they become less widened and discoloured.
in the transitional zone, the infected tubules are narrower
at the ADJ, they are typically narrow and may contain only a few residual bacteria and debris
what are liquefaction foci and transverse cleft? how are they produced? what are their clinical correlates?
when enamel has been cavitated and bacteria infect the dentine, there is a zone of destruction within the dentine, where the dentine becomes necrotic and liquefies. liquefaction foci are liquid areas and the cracks are transverse clefts. produced proteolysis which destroys organic part of dentine.
what effects do secondary and tertiary dentine have on the progression of dental caries?
slow down the progression of dental caries by reducing the size of the pulp chamber and root canal, reducing risk of pulp exposure and subsequent inflammation.
what is attrition?
loss of tooth substance from tooth to tooth contact
what is abrasion?
pathological wearing away of tooth substance by friction of a foreign body
what is erosion?
loss of tooth substance by chemical process not involving bacterial action
