Year 3

Question 0

Summarise the theory of eruptive tooth movement

Answer 0

Tooth eruption is highly regulated process involving the tooth organ (dental follicle, enamel organ) and the surrounding alveolar tissues. Tooth movement results from a balance between tissue destruction (bone, connective tissue and epithelium) and tissue formation (bone, PDL and root)

Question 1

What are the 3 main movements that teeth make during eruption?

Answer 1

1. Pre eruptive tooth movement
2. Eruptive tooth movement
3. Post eruptive tooth movement

Question 2

How often should a routine check up be for children?

Answer 2

1. Shortest time: 3 months
2. Longest interval: 12 months (for patients under 18)
3. Recall intervals of 3, 6, 9 or 12 months are all possible

Question 3

How often should a routine check up be for adults?

Answer 3

1. Shortest time: 3 months
2. Longest interval: 24 months (for patients over 18)
3. Recall intervals of 3, 6, 9, 12, 15, 18, 21 or 24 months are all possible

Question 4

What are the aspects of caries risk assessment?

Answer 4

1. Caries experience:
   a) The extent and number of previous restoration
   b) The extent and number of new restoration
   c) The progression of new lesion
2. Fluoride: type and frequency of use
3. Oral hygiene and extent of plaque present
4. Dietary factors:
   a) Eating habits
   b) Number of main meals
   c) Snacks
   d) Frequency of ferment able carbohydrate intake
5. Bacterial activity: presence and amount of cariogenic bacteria (Lactobacillus and Streptococcus mutans)
6. Saliva:
   a) The amount (quantity)
   b) The buffering capacity (quality)
7. Socio economic status: to evaluate compliance and attendance

Question 5

What are the steps in applying 22 600 ppm flouride varnish?

Answer 5

1. Removal of any gross plaque
2. The teeth is dried with cotton wool rolls or a triple syringe
3. A small quantity of fluoride varnish is placed in a dappens pot
4. A microbrush is used to apply the varnish to pits, fissures and approximal surfaces of teeth and any carious lesion
5. The patient should be advised
   a) Not to eat, drink or rinse for the next 30 minutes
   b) Eat only soft food in the next four hours
   c) Brush the following day

Question 6

What are the contraindications of fluoride varnish?

Answer 6

1. Patients with ulcerative gingivitis and stomatitis
2. Children with history of allergic episodes requiring hospital admission (asthma) due to the colophony component in Duraphat

Question 7

What are the constituent of fluoride varnish?

Answer 7

1. 2.26% (22600ppm) sodium fluoride
2. Ethanol 96%
3. Colophony
4. White wax
5. Shellac
6. Saccharin
7. Raspberry essence

Question 8

When should a tooth be sealed with fissure sealant?

Answer 8

Whenever practicable after tooth eruption and certainly within 2 years of eruption

Question 9

What is infra occlusion?

Answer 9

1. Term for describing the process whereby a tooth fails to achieve or maintain its occlusal relationship with adjacent/opposing teeth
2. Most infra occluded teeth erupt into occlusion but subsequently become ‘submerged’ because the bony growth and development of adjacent teeth continues
3. Most frequently occurs in the early mixed dentition stage
4. Ten times more likely in primary dentition

Question 10

What are the causes of infra occlusion?

Answer 10

1. Tooth ankylosis
2. Impaction/trauma
3. Absence of permanent sucessor
4. Disturbance in local metabolism
5. Infection

Question 11

How is infra occlusion diagnosed?

Answer 11

1. Clinical examination shows tooth is below occlusal plane
2. Tapping of the tooth reveals a percussive ‘cracked teacup’ sound
3. If there is ankylosis the tooth is immobile
4. Radiographic images show lack of well defined periodontal ligament and lamina dura space

Question 12

List the features in Andrew’s six keys

Answer 12

1. Correct molar relationship: neutrocclusion
2. Correct crown angulation: all tooth crowns are angulated mesially
3. Correct crown inclination:
   a) Incisors are inclined towards buccal/labial surface
   b) Buccal segment teeth are inclined lingually
4. No rotation
5. No spaces
6. Flat occlusal plane

Question 13

What is aetiology of crossbites?

Answer 13

1. Crowding (one or two teeth displaced from arch due to lack of space)
2. Retention of primary tooth (deflects the eruption of permanent sucessor)
3. Mismatch in relative width of arch
4. Soft tissue habit such as digit sucking
5. Cleft lip and palate

Question 14

What is the treatment of anterior crossbites?

Answer 14

If only tipping movement is required a removable appliance can be considered. The appliance should incorporate the following features:

1. Good anterior retention to counteract the displacing effect of the active element (Adam clasps creates anchorage to the molars)
2. Buccal capping thick enough to free the occlusion with the opposing arch
3. An active element
   a) T spring
   b) Z spring

Question 15

What are the uses of T spring and Z spring and how do you activate them?

Answer 15

1. Z spring
   a) To tip a single tooth bucally
   b) Activation: pulling the spring 1-2mm away from the baseplate at an angle of approximately 45 degrees in the direction of desired movement
2. T spring
   a) To tip a single premolar or molar tooth buccally
   b) Activation: pulling the spring away from the acrylic at an angle of 45 degrees

Question 16

What are the clinical signs and symptoms of a significant pulpal inflammation of primary molars?

Answer 16

1. Any history of spontaneous severe pain, particularly at night
2. Reported pain on biting
3. The necessity for analgesics
4. The clinical extent of the caries
5. The presence of any intra oral swelling or sinus
6. A history of intra oral or facial swelling

Question 17

What are the special investigation to check for pupal inflammation in primary molars?

Answer 17

1. Gentle finger pressure may determine whether the tooth is mobile or tender
2. Pulpal sensibility testing is not appropriate for primary molars
3. Radiographs are mandatory to provide information of:
   a) Extent of the caries
   b) Presence of peri radicular pathology
   c) Degree of pathology
   d) Physiological root resorption
   e) Presence or successor

Question 18

What are the indications of tooth removal for primary molars?

Answer 18

Medical factors
1. Patient at risk of residual infection
a) Immunocompromised
b) Susceptibility to infective endocarditis
Dental factors
1. Tooth unrestorable after pulp therapy
2. Extensive internal root resorption
3. Large number of carious teeth with likely pulpal involvement (>3)
4. Tooth close to exfoliation (>2/3 of root resorption)
5. Contra lateral tooth already lost
a) In case of first primary molar
b) If indicated orthodontically
6. Extensive pathology or acute facial swelling necessitating emergency admission
Social factors
1. Irregular attender with poor compliance

Question 19

What are the treatment options for primary molars needing pulp therapy?

Answer 19

1. Indirect pulp treatment
   a) To arrest carious process and stimulate formation of reactionary dentine and remineralisation of remaining carious dentine
   b) Indication: deep carious lesion with no pulpal pathosis
   c) LA > Isolate > Remove soft carious dentine > Avoid pulpal exposure> Lining material (reinforced GIC/ hard setting CaOH/ ZnOE) > Restore
2. Direct pulp capping
   a) To encourage formation of dentine bridge at point of pulpal exposure and preserve pulp vitality
   b) Indication: asymptomatic tooth or non carious pulpal exposure
   c) LA > Isolate > Cotton pledged soaked with saline to stem pulpal haemorrhage > Hard setting CaOH/ MTA > Restore
3. Pulpotomy
   a) To remove the irreversibly inflamed coronal pulp leaving behind reversibly inflamed/ healthy radicular pulp
   b) Indication: Carious exposure of vital coronal pulp tissue in tooth that is clinically showing signs of reversible pulpitis
   c) LA > Isolation > Remove caries > Remove of roof of pulp chamber completely > Remove coronal pulp tissue > Achieve pulp haemostasis with sterile cotton wool pledget > Apply medicament (15.5% ferric sulphate/ MTA/ pure CaOH) > Lining material (reinforced GIC/ ZnOE) > Restore
4. Pulpectomy
   a) To remove the irreversibly inflamed pulp tissue, clean the root canal system and obturation the root canals with filling material that will resorb at the same rate as the primary tooth
   b) Indication: tooth with irreversible pulpitis and non vital radicular pulp with no associated infection
   c) LA > Isolate > Remove caries > Remove roof of pulp chamber > Remove pulp tissue > Irrigate (saline/ chlorhexidane/ sodium hypochlorite) > Clean and shape > Obturate with slow setting pure ZnOE/ non setting CaOH or CaOH + iodoform paste) > Restore

Question 20

What are the extrinsic causes of tooth discolouration?

Answer 20

1. Beverage/food
2. Smoking
3. Poor oral hygiene (chromogenic bacteria): green/orange stain
4. Drugs
   a) Iron supplements: black stain
   b) Minocycline: black stain
   c) Chlorhexidane: brown/black stain

Question 21

What are the causes of intrinsic discolouration within enamel?

Answer 21

Local causes
1. Caries
2. Idiopathic
3. Injury/infection from primary predecessor
4. Internal resorption
Systemic causes
1. Amelogenesis imperfecta
2. Drugs (tetracycline)
3. Fluorosis
4. Idiopathic
5. Systemic illness during tooth formation

Question 22

What are the causes of intrinsic discolouration within dentine?

Answer 22

Local causes
1. Caries
2. Internal resorption
3. Metallic restorative material
4. Necrotic pulp tissue
5. Root canal filling material
Systemic causes
1. Bilirubin (haemolytic disease of newborn)
2. Dentinogenesis imperfecta
3. Drugs (tetracycline)
4. Congenital porphyria

Question 23

What are treatment options for tooth discolouration?

Answer 23

1. Hydrochloric acid-pumice micro-abrasion technique
2. Non vital bleaching
3. Vital bleaching: chairside
4. Vital bleaching: nightguard

Question 24

What is the age at which a child is able to give consent for dental treatments?

Answer 24

1. 16 years old | 2. But do not preclude children under 16 from giving consent

Question 25

What are some of the signs suggestive of a non accidental injury?

Answer 25

1. Injuries to both sides of the body 2. Injuries to soft tissues 3. Injuries with particular patterns 4. Any injury that doesn't fit the explanation 5. Delays in presentation 6. Untreated injuries 7. Examples of injuries that should raise suspicion include: a) Pinch marks on ears: especially involving both sides b) Injuries in triangle of safety (ears, side of face, neck and top of shoulders) c) Black eyes: especially is bilateral d) Soft tissues of cheeks e) Intra oral injuries

Question 25

What are the different splinting duration for different injuries?

Answer 25

1. Avulsion: 2 weeks of functional splinting 2. Luxation: 2-4 weeks of functional splinting 3. Apical and middle third root fracture: 4 weeks of functional splinting 4. Coronal third root fracture: 8 weeks of functional splinting 5. Dento alveolar fracture: 3-4 weeks of rigid splinting Functional splinting: composite resin and wire splint with one abutment on each side of injured tooth Rigid splinting: two abutment teeth are incorporated on each side of injured tooth

Question 25

How do functional appliance work?

Answer 25

1. By the principle of posturing the mandible forward in growing patients 2. They are most effective at changing the antero-posterior occlusion between upper and lower arches 3. Used to treat mild to moderate Class II skeletal discrepancy 4. Usually followed by a second phase of fixed appliance 5. They produce predominantly dento-alveolar effects with small skeletal changes

Question 25

When should functional appliance be used to maximise its efficiency?

Answer 25

1. Coinciding with pubertal growth spurt | 2. During the late mixed dentition

Question 25

What are the examples of functional appliance?

Answer 25

1. Twin block appliance: the upper and lower parts fit together using posterior bite blocks with interlocking bite planes which posture the mandible forward 2. Herbst appliance 3. Medium opening activator

Question 25

Who has the ability to give consent to children whose births were registered FROM 1st December 2003 (in England and Wales)?

Answer 25

Parents whose names are on the birth certificate (regardless if they are married or not)

Question 25

Who has the ability to give consent to children whose births were registered BEFORE 1st December 2003 (in England and Wales)?

Answer 25

1. Mother of the child 2. Father a) If he and the mother were married at time of conception, birth or sometimes after (the responsibility is not loss even if they are later on divorced) b) If he and the mother were never married but he has parental responsibility agreement that is registered with the High Court (or ordered from the High Court)

Question 25

What are indications to carry out pulpal therapy in primary molars?

Answer 25

``` Medical factor 1. Patient at risk of extraction a) Bleeding disorders b) Hereditary angio-oedema 2. Patients at risk if GA is required a) Cardiac conditions b) Cystic fibrosis c) Muscular dystrophy Dental factor 1. Minimal number of carious molars that will require pulpal therapy (less than 3) 2. Hypodontia of permanent dentition 3. Where prevention of the migration of FPM is desirable Social factor 1. A regular attender with good compliance ```

Question 26

List the contraindication of fitting Hall crowns

Answer 26

1. Clinical signs and symptoms of irreversible pulpitis or dental abscess 2. Radiographic signs of dental abscess 3. Non physiological mobility 4. Insufficent sound

Question 27

List the indications of fitting Hall crowns

Answer 27

1. Proximal (Class II) lesion (cavitated or non cavitated) 2. Occlusal (Class I) lesion a) Cavitated: if patient is unable to accept partial caries removal technique or conventional restoration b) Non cavitated: if patient is unable to accept fissure sealant or conventional restoration

Question 28

What are the three factors affecting space loss following extraction of primary teeth?

Answer 28

1. Degree of crowding: directly related to the rate and extent of space loss (the more crowded, the more the need for balance) 2. Type of tooth lost: a) Loss of one primary canine may cause centreline shift b) Loss of primary molar (especially second molar) may allow mesial drift of the FPM 3. Age of child: the earlier the tooth is lost, the greater the opportunity for drift

Question 29

What is the strategy when extracting primary canines?

Answer 29

1. Early loss of canine (except in spaced dentition) is likely to have most effect on centreline shift 2. The need to balance is high in this situation 3. However if an unbalanced extraction already occurred a) Centreline shift does not occur: don't balance b) Centreline shift with complete space closure: delay balance until full orthodontic assessment is made c) Centreline shift with remaining space mesial to extraction site: monitor to determine if tooth movement is continuing 4. Compensation is not needed

Question 30

What is the strategy when extracting primary molars?

Answer 30

A) First molar 1. Balancing extraction may be needed in a crowded arch 2. Compensation is not needed 3. When crowding is severe, space maintainer should be fitted after extraction B) Second molar 1. Balancing is not needed as there is no appreciable effect on centreline shift 2. However it may cause serious forward movement and tilting of adjacent FPM 3. Consideration should be given to fitting a space maintainer after extraction (except in spaced arches)

Question 31

What are the different types of space maintainer?

Answer 31

1. Tooth 2. Band and loop (single tooth space) 3. Lingual or palatal arch (best for bilateral spaces)

Question 32

What are the 3 features indicative of good development of the primary dentition?

Answer 32

1. Incisor spacing 2. Anthropoid spacing (space between mesial aspect of maxillary canine and distal aspect of mandibular canine) 3. Straight or mesial step primary second molar occlusion

Question 33

What is Leeway space?

Answer 33

1. In each quadrant the primary canine and molars together are larger than the succeeding canine and premolars 2. The different in tooth space between the two dentitions is known as Leeway space

Question 34

What are the components in removable appliance?

Answer 34

1. Active component 2. Primary retention 3. Secondary retention 4. Anchorage 5. Baseplate and extension 6. Bite plane

Question 35

Describe horizontal and vertical parallax

Answer 35

``` Horizontal parallax 1. Anterior occlusal and periapical 2. Two periapical Vertical parallax 1. Anterior occlusal and DPT 2. Periapical and DPT *horizontal parallax in more reliable than vertical in localising unerupted tooth ```

Question 36

List the different treatment options for ectopic canine

Answer 36

1. Interception treatment by extraction of deciduous canine 2. Surgical exposure and orthodontic alignment 3. Surgical removal of palatally ectopic permanent canine 4. Transplantation 5. No active treatment (leave and observe)

Question 37

State the guidelines for inspection and palpation in the canine region

Answer 37

1. Age 8: routine palpation 2. Age 10-11: should be palpable in the buccal sulcus 3. Age 10-13: suitable for successful interceptive treatment

Question 38

What are the principle factors dictating whether a FPM is recommended for balancing or compensating extraction?

Answer 38

1. Which FPM requires enforced reaction 2. The overall condition and long term prognosis 3. Teeth present within the developing dentition 4. The underlying malocclusion

Question 39

What is a general rule for compensating and balancing extraction of FPM?

Answer 39

1. Compensating extraction for upper FPM is often recommended when extraction of the lower is required a) Prevents over eruption of the unopposed upper FPM b) Prevents mesial movement of the lower second molar 2. Balancing extraction of healthy first molars is generally not recommended