2 and 3

Question 1

what oral disease is more prevalent in younger population?

Answer 1

caries

Question 2

what oral disease is more prevalent in older population?

Answer 2

periodontal disease

Question 3

etiopathology

Answer 3

origin of disease

Question 4

what factors do you need to have caries?

Answer 4

• host (tooth)
• dental plaque
• diet (drive, feed bacteria)
• time

Question 5

how can time impact caries development?

Answer 5

frequency
- how many times eat a diet that generates an acid challenge?

more frequent exposure = shorter caries development time

Question 6

what are the characteristics of bacteria that is most fit for caries development?

Answer 6

Bacteria that is most fit for the procedure of installing itself to surface of tooth is the most successful

Question 7

how do bacteria adhere to tooth surface?

Answer 7

Tooth surface (enamel, Apatite) structure is adapted to receive the first coat of proteins
- Sticky out bits are protein – induced by host to coat the tooth
Necessary because surface is harsh and will damage the mucosa and tongue

Protein Coat is a lubricate – protective mechanism

Bacteria has adapted to that surface.

• Cannot attached to enamel but can to protein coat
• Surface of protein exposed to external changes conformation and bacteria recognise this when coating the enamel

Question 8

secondary elements of aetiology of caries

Answer 8

• Fluoride
• Diet – what and how frequent
• Microbial/ bacteria species
• Buffer capacity – saliva
• Sugar clearance rate – saliva
• social class
• education
• behaviour and attitude

Question 9

what is caries?

Answer 9

Demineralisation of tooth surface produced by bacteria that produce acid (acidogenic bacteria)

• Progressive demineralising effect
• Imbalance generate by acidogenic bacteria causes caries

Question 10

what are the most common acids made by acidogenic bacteria?

Answer 10

lactic acid

acetic acid

Question 11

how are white spot lesions formed?

Answer 11

Lesion is promoted by succession of demineralisation and remineralisation and remineralisation of subsurface takes longer than surface

exchange of acids ions inside is more efficient on sub surface as quicker demineralisation of enamel
- Surface is highly mineralised compared to subsurface

Question 12

why shouldn’t you probe a white spot lesion?

Answer 12

can fracture

in tact surface but highly demineralised subsurface

Question 13

what is the structure of subsurface enamel lesion?

Answer 13

enlarged gaps between rods

• rod becomes thinner so gaps between them become more present
• crystallites become thinner (rounder shape)

rod length preserved

interrod region damage but the length of rod is preserved

Question 14

where is the most common area on tooth to get dental plaque?

Answer 14

under contact point

Question 15

what happens to dentine when a white spot lesion is generated on enamel?

Answer 15

initial sclerosis of dentine

Question 16

sclerotic

Answer 16

becomes rigid and unresponsive

losing ability to adapt

Question 17

what is the second stage in enamel white spot lesion after initial sclerosis of dentine?

Answer 17

Demineralisation of enamel causes demineralisation of dentine
- Sclerosis progresses

Question 18

what happens after dentine begins to demineralise in enamel white spot lesion progression?

Answer 18

continues to demineralise and get new formation of tertiary dentine

tertiary dentine formation begins before any tissue loss
- only mineral loss currently

Question 19

what happens after tertiary dentine formation in enamel white spot lesion progression?

Answer 19

cavitation

• Sclerotic dentine still progressing
• Increase in tertiary dentine

Progression to reach dentine of cavity
- Presence of microorganism in dentine

Question 20

what is the appearance of an active white spot lesion?

Answer 20

chalk appearance

on gingiva margin (can get inflammation as don’)t brush effectively

Question 21

what is the histological appearance of active white spot lesion compared to remineralise white spot lesions? (on SEM)

Answer 21

active lesions has rough surface
- crystallites are there but thinner
- blobby arrangement,
reminerlaistion surface becomes smoother.
- Rough means more SA for plaque build up

Question 22

what happens to the pH of mature plaque when exposed to sucrose?

Answer 22

pH of mature plaque drops when exposed to sucrose

• the organic structure of mature plaque restricts the action of saliva buffer
• Plaque metabolises the sugar so insoluble in structure so affects buffer in saliva

Lower pH and higher H+

Active lesions pH goes below threshold of 5.5

Question 23

what feature of mature plaque aids demineralisation?

Answer 23

the organic structure of mature plaque restricts the action of saliva buffer
- Plaque metabolises the sugar so insoluble in structure so affects buffer in saliva

Question 24

what relationship is broken down between in the case of caries?

Answer 24

breakdown of balance between remineralisation and demineralisation

Question 25

what should be aimed for to minimise caries formation?

Answer 25

maintain pH in a neutral position by reducing sugar frequency

Question 26

what is ecological shift impact on caries?

Answer 26

Streptococcus Mutans – survives well in acid – other species die. - Fluoride has the ability to stop pump which allows S.Mutans to live in acid bacteria Lactobacilli – only in large carious lesions Acidogenic bacteria– use sugar to make energy and acid Not early inducers come along and start making plaque

Question 27

what are acidogenic bacteria?

Answer 27

use sugar to make energy and acid Not early inducers come along and start making plaque - S.Mutans and Lactobacilli

Question 28

what are proteolytic bacteria?

Answer 28

breakdown proteins not sugar for energy S.sanguinis S.gordonii

Question 29

how are crystallites organised in fissures?

Answer 29

they run perpendicular to surface

Question 30

why are pits and fissures more prone to caries than surfaces?

Answer 30

Saliva buffers but more at surface regions Crystallites organised in fissure differently – run perpendicular to surface Demineralisation at core central region more than surface - Specific shape triangle base towards dentine Interproximal other way round

Question 31

what is the characteristic shape of pits and fissure caries?

Answer 31

triangle shape small lesion on surface and larger damage at base

Question 32

what happens to the pace of demineralisation when caries reaches dentine?

Answer 32

takes longer to reach dentine but then spreads quickly | - because dentinal tubules branch at ADJ

Question 33

basic steps of process of caries

Answer 33

- plaque bacteria adhere to surface of enamel - sclerosis in dentine - demineralisation with tertiary dentine formation - bacteria invasion

Question 34

how to detect cavitation?

Answer 34

Opaque enamel colour due to white spot Dark grey shadow under enamel – dentine compromised Clean the tooth and polish and see if can see lesion = cavitation - Radiographs can confirm

Question 35

what is the physical difference between demineralised and mineralised dentine?

Answer 35

demineralised dentine is soft mineralised dentine is hard

Question 36

what is an active root caries lesion like?

Answer 36

wet surface whereas non active would be dark and non wet

Question 37

why is it hard to restore an active root caries lesion?

Answer 37

surrounding material is not hard and strong enough to glue to material - lacks enamel at lesion (only some cementum and dentine which are not easy to make a good strong bond) Poor retention - Fall off – replace – increase cavity size Procedure can be more harm than good – need to tell patient likely to fail

Question 38

in order to have fluoroapatite in enamel what needs to occur?

Answer 38

demineralisation as F needs to substitute in

Question 39

what happens to F concentration when you go deeper into tooth structure?

Answer 39

F concentration decreases with depth of tooth | so demineralisation increases

Question 40

what is the caries case for higher calculus levels?

Answer 40

less caries same factors promote caries and calculus (high Ca and PO4 but less H+ so decreased caries risk) - high calculus levels tend to have less caries - similar de/remineralisation process

Question 41

what is an important element of caries treatment?

Answer 41

patient attitude and behaviours change so improved oral hygiene - can lead to restoration failure