Disease and degeneration

Question 1

classes of disease

Answer 1

1. tooth decay (plaque (tartar) & caries

2. gum disease (gingivitis & periodontal disease)

Question 2

tooth decay

Answer 2

2 contributing factors:

1. plaque–> tartar build up
2. acid erosion via bacterial action: caries

Question 3

Plaque

Answer 3

it is a mixed microbial biofilm, occurs naturally.

dental pellicle: response to clean teeth, conditioned by ‘inhospitable’ salivary proteins and glycoproteins

can develop to 100-1000s of diff species of bacteria, build up = tarter/calculus –> caries/periodontal disease

microbial composition sensitive to environmental change, even changes in host diet

Question 4

plaque formulation steps

Answer 4

major sites of accumulation:
fissures of molar teeth
area bounded by the margin of gum & teeth
b/n adjacent teeth

steps:

1. colonisation by pioneer species
2. outgrowth
3. secondary colonisation & multiplication
4. equilibrium community established

Question 5

plaque formulation

1. colonisation by pioneer species

Answer 5

1. colonisation by pioneer species
   biofilm on dental pellicle, includes: s. sangius, once firmly attached it resits brushing, reestablish 2 hrs of prof cleaning
   views:
   phase 1: microbes can be held longer by electrostatic & hydrophobic interactions
   phase 2: microbes become irreverisbly attached by extracellular glucosyl-transferases and fructosyl-transferases

Question 6

plaque formulation

2. outgrowth

Answer 6

once attached, pioneer species proliferate, forming monolayer than multilayers

Question 7

plaque formulation

3. secondary colonisation & multiplication

Answer 7

pioner biofilm is a substrate for more species colonisation

overall cell density decreases, more polysaccharide sysnthesis progresses

24hrs maturing plaque = wide variety of bacteria

Question 8

plaque formulation

4. equilibrium community established

Answer 8

plaque biofilm limited by salivary & mastication shear forces

several days: stable plaque composition =
products of 1 feeds another
carbohydrates broken down by species working cooperatively

Question 9

plaque calcification

Answer 9

after calcified = calculus or tartar

mix of mineral phases depends on local condition: ion species & concentration. pH

get a mix of: brushite, OCP, TCP & apatite

Question 10

plaque and tartar

Answer 10

2 types tarter: supra (above gum line, yellow), sub (below gum line, brown) gingival

factors to increase plaque and tartar:

1. reduce function of saliva: tooth defects, tooth position, lack of lip seal, mouth breathing, dietary extremes
2. facilitate attachment/formation: dental fixtures, cavities, rough restorations, poor hygiene (brushing)

Question 11

Caries

Answer 11

dissolution of material from teeth surface: from acids (bacteria fermentation or food)

decalcification of enamel, esp fissures, on occusal surfaces of teeth (

Question 12

factors affecting caries progression

Answer 12

types of bacteria present
dental substrate (e.g. dentine & cementum vs enamel)
time (to facilitate mineralisation)
patients lifestyle - smoking, hygiene

Question 13

Prevention of caries

Answer 13

fluoride treatment
fissure sealants
gd dental hygiene