Child dental health and orthodontics

Question 1

1.1 b) What special investigations to investigate for maxillary impacted canine in 13-year-old?

Answer 1

In first instance RG should be taken to determine whether the tooth is present.
- USO or PA should show the tooth, or if necessary a DPT.
- If only one view is taken and a tooth is visible, then a further RG in another plane can be taken to allow accurate location of the tooth.
- Use parallax technique and SLOB (same lingual, opposite buccal) to locate the tooth.

Question 2

1.1 a) Maxillary canines are commonly impacted. What signs might a GDP see in a pt’s mouth that would make them suspicious that a maxillary canine was impacted in a 13 year-old patient? (5)

Answer 2

1. Absence of maxillary canine in the appropriate position in the mouth
2. Absence of a canine bulge palpable in the buccal sulcus
3. Deciduous upper canine is still in place and firm
4. Protrusion, small mesiodistal width, peg-shaped or congenitally absent lateral incisors.
5. Other associated dental anomalies - hypodontia, malformed teeth, delayed eruption of teeth, enamel hypoplasia.

Question 3

1.1 c) In what circumstances would you consider surgical removal of an impacted canine tooth? (3)

Answer 3

1. When the tooth shows pathology associated with it, e.g. dentigerous cyst or root resorption
2. When there is evidence of root resorption of adjacent teeth which appears to be caused by the impacted canine tooth.
3. Where a pt is having orthodontic treatment to align the adjacent teeth to create an arch form without utilising the canine and the canine is thought to be in the way of planned orthodontic tooth movement.

Question 4

1.1 d) In what circumstances would you consider leaving the impacted canine where it is? (5)

Answer 4

1. Where there is no pathology associated with the impacted canine.
2. The patient is not having orthodontic treatment that requires its removal.
3. There is a risk of damaging the adjacent teeth/tooth by removing it.
4. When a patient declines to have it removed even though there are indications to remove it.
5. Where there are contraindications in the medical history to removal of the tooth. e.g. pt at risk under GA

Question 5

1.2 a) What are the various components of a removable orthodontic appliance and what function does each one perform? (4)

Answer 5

i) Active component = site of delivery of the force to move a tooth/teeth

ii) Retentive component = component that keeps the appliance in the mouth

iii) Anchorage component = provides resistance to unwanted teeth/tooth movement. (Every action has an equal and opposite reaction and hence there is always a reaction from the active components, and anchorage is the source of resistance to this movement)

iv) Baseplate = this holds all the components together.

Question 6

b) Adam’s clasps are often used to keep an appliance in place, what are the advantages of the design of this component? (3)

Answer 6

i) They provide retention and anchorage

ii) Easy to adjust: anterior and posterior teeth

iii) Versatile: auxiliary fittings include double clasps, hooks for elastics, tubes for headgear attachment.

Question 7

c) What other designs of such components are used to keep an appliance in place? (3) (not adam’s clasps)

Answer 7

i) Ball hooks
ii) Southend clasp in the incisors
iii) Fitted labial bow

Question 8

d) Appliances may be designed with bite planes: when would you use and anterior bite plane and when would you use a posterior bite plane?

Answer 8

i) Anterior bite planes decrease overbite  Anterior bite planes open the bite to allow the posterior teeth to erupt while preventing the anterior teeth from erupting any more. As the posterior teeth erupt there is vertical development of the alveolus and the condyles will also grow. These are only used in pts who are still actively growing.

ii) Posterior bit planes decrease openbite/reduced overbite will increase  Posterior bite planes allow anterior to erupt with posterior teeth are prevented from further eruption by the bite plane. Will cause a reduced overbite to increase, but again can only be used in a pt who is still actively growing.

Question 9

e) What are some advantages of removable orthodontic appliances? (7)

Answer 9

i) Effective for simple tipping of favourably inclined teeth, (often mesial) over short distances

ii) Can transmit forces to blocks of teeth

iii) Easy to clean for patients

iv) Cheap to make and cheap clinically as use of minimal chair-side time

v) Aesthetic

vi) Provide valuable anchorage

vii) Self-limiting

Question 10

1.4 a) Name two conditions that may result in delayed eruption of primary teeth. (4)

Answer 10

i) Preterm birth
ii) Chromosomal abnormalities, e.g. Down syndrome, Turner’s syndrome
iii) Nutritional deficiency
iv) Hereditary gingival fibromatosis

Question 11

1.4 b) Name two local conditions and a systemic condition that may delay permanent tooth eruption. Local (4) Systemic (6)

Answer 11

i) Local conditions
(1) supernumerary teeth
(2) crowding
(3) cystic change around the tooth follicle
(4) ectopic position of the tooth germ

ii) General conditions
(1) Cleidocranial dysplasia
(2) Chromosomal abnormalities (Down syndrome, Turner’s syndrome)
(3) Nutritional deficiencies
(4) Hereditary gingival fibromatosis
(5) Hypothyroidism
(6) Hypopituitarism

Question 12

1.4 c) How common is hypodontia in the primary and permanent dentition?

Answer 12

i) Prevalence of hypodontia in primary dentition is less than 1% and in the permanent dentition it is about 3.5-6.5% (Di Biase DD. Dental Practitioner & Dental Record. 22(3):95:108, 1971 Nov.)

Question 13

1.4 d) Which sex is hypodontia most common in?

Answer 13

i) Females

Question 14

1.5 a) What do you understand by the term ‘infraocclusion’ and how is it graded?

Answer 14

i) Infraoccluded teeth are teeth that fail to maintain their occlusal relationship with opposing or adjacent teeth. They were previously called submerged or ankylosed teeth. Infraocclusion most commonly affects the deciduous mandibular molars. It is graded as follows:

(1) Grade 1 = the occlusal surface of the tooth is above the contact point of the adjacent tooth.
(2) Grade 2 = the occlusal surface of the tooth is at the contact point of the adjacent tooth
(3) Grade 3 = the occlusal surface of the tooth is below the contact bone of the adjacent tooth.

Question 15

1.5 b) An 11-year old boy presents with an infraoccluded lower second deciduous molar. What percentage of primary molars are affected by this condition?

Answer 15

i) 8-14%

Question 16

c) How would you manage this problem? (11yo boy with infraoccluded lower second deciduous molar).

Answer 16

i) Take a radiograph to see if there is a permanent successor. If there is one, it is likely that the infraoccluded second deciduous molar will exfoliate at the same time as the contralateral tooth, when the permanent successor starts to erupt.

Question 17

1.5 d) When would you refer for surgical removal? (2) (infraoccluded primary molars)

Answer 17

i) When there is no permanent successor and the tooth will probably ‘disappear’ below the gingival margin.
ii) Tipping of the adjacent teeth makes accessing the primary molar difficult.
iii) Ankylosis with no PDL space?

Question 18

1.5 e) If there is a permanent successor and the second deciduous molar is still infraoccluded and is below the gingival tissue, what could happen to the second deciduous molar? What will you need to consider after removal of the second deciduous molar?

Answer 18

i) The second deciduous molar may have ankylosed.

ii) Space maintenance will need to be considered after the extraction to allow eruption of the permanent molar and prevent tipping of the adjacent teeth.

Question 19

1.6 a) A fit and healthy 12-year old girl attends with her mother following an accident in which she fell off the apparatus at her gym club. She has banged both her upper anterior teeth. Examination reveals no extraoral injuries, but both the upper central incisors are mobile and the crowns are partially displaced. What special tests would you carry out and why?

Answer 19

i) Vitality tests of all upper and lower incisors as they may have been injured in the accident. (Sensibility, TTP, mobility, colour, RGs)
ii) Periapical radiographs and an upper standard occlusal view to see if the roots are fractured.

Question 20

b) The upper central incisors are fractured in the mid-third of the roots. What treatment would you carry out and how long must that treatment be done?

Answer 20

i) Splint the teeth using a passive and flexible splint that allows physiological tooth movement. A wire splint that is bonded to the injury teeth and one healthy tooth on either side of the injury teeth using acid-etch composite is easy to construct and well tolerate.
ii) The splint must be kept in place for 4 weeks.

Question 21

c) If the coronal portion of the tooth became non-vital, what treatment would you carry out?

Answer 21

i) The pulp should be extirpated to the fracture line. The root canal is filled with non-setting calcium hydroxide to encourage barrier formation coronal to the fracture line. The CaOH should be changed every 3 months until the barrier forms, at which point the coronal root canal should be filled with gutta percha, and the tooth kept under review. (/MTA for apexification)

Question 22

d) If there were no root fractures, would your management have changed? (teeth mobile and palatally displaced)

Answer 22

i) The teeth are mobile and palatally displaced so they must have undergone some type of displacement injury. These would still require flexible splinting e.g. 2/4 weeks depending on luxation injury type.

Question 23

e) If a dentoalveolar fracture has been diagnosed, would your management have changed and if so, how? (teeth are mobile and displaced palatally)

Answer 23

i) Lateral luxation injuries require repositioning of tooth and splint for 4 weeks.

Question 24

1.7 a) What do you understand by the term ‘behaviour management’?

Answer 24

i) Behaviour management is a way of encouraging a child to have a positive attitude towards oral health and health care so that treatment can be carried out. It is based on establishing communication while alleviating anxiety and fear, as well as building a trusting relationship between the dentist/therapist and delivering dental care.

Question 25

1.7 b) Name three types of communicative management. (5)

Answer 25

i) Non-verbal communication
ii) Tell, show, do
iii) Voice control
iv) Distraction
v) Positive reinforcement

Question 26

1.7 c) If a child is unable to tolerate dental treatment, drugs may be administered to help the child cope with the procedure. One way of drug delivery is inhalation sedation. What drug is commonly used with this method?

Answer 26

i) Nitrous oxide

Question 27

1.7 d) Give two contraindications to use of inhalation sedation drug. (6)

Answer 27

i) Sickle cell disease
ii) Severe emotional disturbances
iii) Chronic obstructive airway disease
iv) Cooperative patient
v) Drug related dependency
vi) First trimester pregnancy

Question 28

1.7 e) Name another sedative drug that may be used and the possible routes of delivery.

Answer 28

i) Midazolam – oral, intranasal sedation.

Question 29

1.8 a) A fit and healthy 15-year old girl complains of a wobbly upper tooth. Examination reveals that the tooth is a deciduous upper left canine and the permanent canine is not visible. Describe how you would determine whether there is an unerupted permanent canine.

Answer 29

i) Clinical examination – the angulation of lateral incisors may give a clue. A buccally placed canine tooth may push the apex of a lateral incisor palatally, leaving the lateral incisor proclined.

ii) Palpation of the buccal sulcus and palate may reveal a bulge, which could be due to an underlying tooth.

iii) Radiographs are the definitive method of determining presence or absence of the permanent canine tooth.

Question 30

1.8 b) You have a panoramic radiograph and a periapical view. Describe how you could use these images to determine the exact position of an unerupted tooth.

Answer 30

i) Parallax technique.
ii) When two views are taken with different angulations, any object that is further away from the tube will move in the same direction as the tube.
iii) This can be carried out in either the vertical or horizontal plane.
iv) With these two planes, the rube has shifted from a near horizontal position in the panoramic radiograph to a much higher angulation in the periapical.
v) If the canine tooth appears lower on the panoramic radiograph than it does on the PA then it has moved with the tube and is palatally situated and vice versa.
vi) If the tooth does not move at all, then it is in line of the arch.

Question 31

1.8 c) Name two other combinations of radiographs that could be used to localise the tooth. (3)

Answer 31

i) Two PAs taken at different horizontal angulations.
ii) PA + USO
iii) DPT + USO

Question 32

1.8 d) What single radiograph could be taken to determine whether the canine is buccally or palatally displaced?

Answer 32

i) Vertex occlusal radiograph, although this is not commonly used due to high radiation dosage.

Question 33

1.9 a) What are the treatment options for impacted permanent canines when the deciduous predecessor has been lost? Give an advantage and disadvantage or each option.

Answer 33

1. No intervention and monitor impacted canine tooth
   + = easy
   - = Still no tooth in gap – need prosthesis
2. Removal of impacted tooth
   + = No possibility of cystic change
   - = Surgical procedures; damage to adjacent teeth/structures; no tooth in gap – need prosthesis
3. Surgical exposure with orthodontically assisted eruption
   + = Tooth ends up in proper position with an intact periodontal ligament
   - = Surgery; patient needs to wear an orthodontic appliance (usually fixed appliance; prolonged treatment; tooth may not erupt.
4. Transplantation of canine
   + = Quick, tooth immediately put in place
   - = Surgery; tooth may become ankylosed; loss of vitality; long-term prognosis not as good as teeth that erupt normally.

Question 34

1.10 a) What types of appliance are the Andresen appliance, Frankel appliance, and twin block appliance? How do they work?

Answer 34

i) They are all functional appliances.

ii) A functional appliance is an orthodontic appliance that uses, guides or eliminates the forces generated by the orofacial musculature, tooth eruption and facial growth to correct a malocclusion.

Question 35

b) What age group of patients are they most effective in? (functional appliances)

Answer 35

i) Growing children, preferable before the pubertal growth spurt as they use the forces of growth to correct the malocclusion.

Question 36

c) Which type of malocclusion is most successfully treated with these appliances? What skeletal effects are thought to occur?

Answer 36

i) Their main use is to treat class II malocclusions, especially Class II div 1. However, they can also be used to treat anterior open bites and Class III malocclusions.

ii) There is still confusion about the exact effects of functional appliances but it is thought that they provide a combination of both skeletal and dental effects. With respect to the mandible, it has been said that the mandible is stimulated to grow and the glenoid fossa remodels forwards as the appliances pull the condylar cartilage forwards, beyond the glenoid fossa. It is also claimed that forward maxillary growth is inhibited.

Question 37

d) Name two skeletal and two dental changes that are reported to occur with the use of these appliances? (4 each)

Answer 37

i) Skeletal changes – any two of the following:
(1) Restraint or redirection of forward maxillary growth
(2) Optimisation of mandibular growth
(3) Forward movement of glenoid fossa
(4) Increase in lower facial height

ii) Dental changes – any two of the following:
(1) Palatal tipping of upper incisors
(2) Labial tipping of lower incisors
(3) Inhibition of forward movement of maxillary molars
(4) Mesial and vertical eruption of mandibular molars

Question 38

1.11 a) What determine(s) the response of a tooth when force is applied to it?

Answer 38

i) The magnitude and duration of the force

Question 39

b) What changes are seen in the periodontal ligament when orthodontic forces are applied to teeth?

Answer 39

i) Depending on the side:

(1) Tension side – stretching of the periodontal ligament fibres and stimulation of the osteoblasts on the bone surface, leading to bone deposition.

(2) Compression side – compression of blood vessels, osteoclast accumulation which result in resorption of bone and formation of Howship lacunae into which fibrous tissue is deposited.

Question 40

c) Give five complications of orthodontic treatment. (9)

Answer 40

i) Root resorption
ii) Enamel decalcification
iii) Gingivitis
iv) Trauma/ulceration from attachment
v) Allergy from attachments, etc (nickel)
vi) Relapse
vii) Incomplete treatment
viii) Loss of tooth vitality
ix) Pt dissatisfaction

Question 41

1.12 a) In the current economic situation health providers need to show that orthodontic services are appropriately allocated. Name a commonly used index that categorises the urgency and need for orthodontic treatment.

Answer 41

i) The Index of Orthodontic Treatment Need (IOTN).
ii) This was developed to help determine the likely impact of a malocclusion on an individual’s dental health and psychological well-being.

Question 42

1.12 b) How many components are there in the index and what grades does this index incorporate?

Answer 42

i) Two components: dental health and aesthetic components.
ii) DHC = 5 grades and looks at traits that may affect function and longevity of dentition with grad 1 indicating no tx need and grade 5 very great need.
iii) AC = consists of 10 photographs scored 1-10 wehere score 1 is aestheticaly pleasing and 10 is the least.
iv) NHS treatment for under 18 in pts with DHC 4 or 5 or DHC 3 + AC of 6+

Question 43

1.13 a) A 12-year-old girl complains of a ‘gap between her upper central incisors; that she is getting teased about at school. Name 4 causes of midline diastema. (6)

Answer 43

a) A 12-year-old girl complains of a ‘gap between her upper central incisors; that she is getting teased about at school. Name 4 causes of midline diastema. (6)
i) Physiological (central incisors erupt first and a diastema may be present until the upper canines erupt)
ii) Small teeth in large jaw (including peg laterals)
iii) Missing teeth
iv) Midline supernumerary (mesiodens), odontoma
v) Proclination of upper labial segment
vi) Prominent labial frenum (actual role is unclear although it is often cited as a cause).

Question 44

1.13 b) How would you determine the cause of the diastema?

Answer 44

i) History and examination. In particular, look for:
(1) A prominent labial frenum. Pull the lip to put the fraenum under tension and look for blanching of the incisive papilla.
(2) Proclination of upper incisors
(3) Size of the teeth in the upper labial segment
ii) Radiographs will help confirm if any teeth are missing or the presence of supernumerary teeth. A notch of the interdental bone between the upper central incisors is another sign of a prominent fraenum.

Question 45

1.13 c) Once the potential cause of the diastema has been identified how should the pt be managed?

Answer 45

i) If the upper canines are unerupted and the diastema is <3mm then reassess after eruption of the canines.

ii) If the upper canines are unerupted and the diastema is >3mm orthodontic treatment may be needed when the canines erupt to approximate the incisors.

iii) If the upper canines are erupted then the incisors will require orthodontic approximation or restorative treatment to reduce the gap.

iv) If there is prominent fraenum, the patient should be referred for an opinion/treatment of the fraenum. Surgical tx would involve a fraenectomy.

v) If a supernumerary or odontoma is present then refer for surgical removal.

vi) If teeth are missing, consider closing the midline diastema and a restoration option for the space created further laterally.

vii) If the upper labial segment is proclined, a full orthodontic assessment is needed to determine if it is treatable by orthodontics alone or may require surgical intervention at a later date.

viii) If the upper central and lateral incisors are very narrow with spacing then it may be possible to refer for restorative treatment to restore the teeth with composite, porcelain veneers or crowns to increase the width and minimise the gaps.

Question 46

1.14 a) How common is cleft lip and palate in western Europe?

Answer 46

i) 1:700 births

Question 47

1.17 b) At what age do most units carry out closure of the cleft lip?

Answer 47

i) 3 months

Question 48

1.17 c) At what age do most unity carry out repair of cleft palate?

Answer 48

i) Between 9 and 18 months

Question 49

d) Name two dental anomalies that often occur in cleft patients.(4)

Answer 49

i) Hypodontia
ii) Supernumerary teeth
iii) Delayed eruption of teeth
iv) Hypoplasia

Question 50

1.14 e) At what stage may orthodontic treatment be needed? (cleft lip/palate)

Answer 50

i) In the mixed and/or permanent dentition:
(1) Mixed dentition – Proclination of upper incisors may be necessary if they erupt in lingual occlusion, otherwise orthodontic treatment is better deferred until just prior to alveolar bone grafting. Orthodontic expansion of the collapsed arch and alignment of upper incisors is required prior to alveolar bone grafting.

(2) Permanent dentition – fixed appliances are usually required for alignment and space closure. Orthognathic surgery and associated orthodontic treatment is carried out when growth is completed. Patients classically have a hypoplastic maxilla with a class III malocclusion, and orthognathic surgery is considered for improvement in aesthetics and function.

Question 51

1.14 f) What may need to be carried out to aid eruption of the maxillary canine of the cleft side and when would this be done?

Answer 51

i) Alveolar bone grafting (grafting or placement of cancellous and/or cortical bone from another site, e.g. hip or tibia, to the cleft alveolus) is carried out to make a one-piece maxilla. The grafting is usually done between the ages of 8 and 11 years when the canine root is two-thirds formed, to provide bone for: the canine to erupt into; support for the alar base of the nose; provide an intact arch to allow tooth orthodontic movement; and aid closure of any oronasal fistula.

Question 52

1.15 a)How would you advise parents to administer an appropriate fluoride dosage regimen at home for children in the following age groups: a) Up to 3 years b) 3-6 years c) from 7 years and young adults d) from 7 years and young adults (high caries risk/undergoing orthodontic treatment, those with special needs).

Answer 52

i) Children aged up to 3 years:
(1) Parents should brush or supervise brushing
(2) Only use a smear of toothpaste containing no less than 1000ppm fluoride
(3) As soon as teeth erupt in the mouth, brush them twice daily
ii) Children aged 3-6:
(1) Use a pea-sized amount of toothpaste containing 1350-1500ppm fluoride
(2) Spit out after brushing and do not rinse (al children 3-6 years)
iii) Children 7+ + young adults
(1) Use fluoridated toothpaste (1350 fluoride or above)
(2) Spit out after brushing and do not rinse
iv) Children 7+ + young adults (high caries risk/undergoing orthodontic treatment, those with special needs):
(1) Use fluoridated toothpaste (1350ppm fluoride or above)
(2) Spit out after brushing and do not rinse
(3) Use fluoride mouthrinse daily (0.5% NaF) at a different time from brushing.

Question 53

1.15 b)What is the recommended professional intervention regarding fluoride for children in the following age groups? A) 3-6 years. B) from 7 years and young adults

Answer 53

i) Children aged 3-6years:
(1) Apply fluoride varnish to teeth twice yearly (2.2% F-)

ii) Children aged 3-6 years (high risk)
(1) Apply fluoride varnish to teeth 3-4 times yearly (2.2% F-)
(2) Prescribe fluoride supplement and advise regarding maximising benefit
(3) Reduced recall interval
(4) Investigate diet and assist to adopt good dietary practice
(5) Ensure medication is sugar-free or given to minimise cariogenic effects

iii) Children aged 7+ +. Young adults:
(1) Apply fluoride varnish to teeth twice yearly (2.2% F-)

iv) Children aged 7 years and young adults (high risk):
(1) Apply fluoride varnish to teeth 3-4 times years (2.2% F-)
(2) For those 8+ years, prescribe daily fluoride rinse.
(3) For those 10+ years, prescribe 2800 ppm toothpaste
(4) For those 16+ years, consider prescription of 5000ppm toothpaste.

v) For additional also consider the need to:
(1) Fissure seal permanent molars with resin sealant
(2) Investigate diet and assist adoption of good dietary practice.

Question 54

1.15 c) Teeth start forming before the age of 6 months so why are fluoride supplements not given to younger children.

Answer 54

i) Infants <6 months of age do not have adequate renal function to excrete fluoride. Hence fluoride is contraindicated until children are at least 6 months old.

Question 55

1.16 a) What are the factors that would put a child at high risk for developing caries?

Answer 55

i) Social factors:
(1) Family belonging to a lower socioeconomic group
(2) Irregular dental attendance
(3) Poor knowledge of dental disease
(4) Siblings with high caries rates

ii) Dietary factors:
(1) Easily available sugary snacks
(2) Frequent sugar intake

iii) Oral hygiene factors:
(1) Poor plaque control
(2) No fluoride

iv) Medical history factors:
(1) Reduced salivary flow, or reduce buffering capacity
(2) Medically compromised
(3) Physical disability
(4) Cariogenic medicine taken long term
(5) High streptococcus mutans and lactobacillus counts

Question 56

1.16 b) How would you carry out a diet analysis for a child?

Answer 56

i) You need to ask the parents (carer) to record on a sheet the time, the food and the amount of everything that is eaten over a 3-4 day period. Try to include one day from the weekend as dietary habits are often different then.

Question 57

1.16 c) List four pieces of dietary advice that you would give to a parent/patient.

Answer 57

i) Encourage:
(1) Safe snacks (but beware of high-salt foods) e.g. nuts, fruit, bread, cheese
(2) Safe drinks – water, milk, tea with no sugar
(3) Tooth brushing

ii) Limit:
(1) Frequency of sugar-containing food and drinks
(2) Sweets to mealtimes or one day a week

iii) Avoid:
(1) Chewy sweety in particular
(2) Sweetened drinks is a bottle

iv) Discourage:
(1) There is some controversy surrounding long term breast feeding, but breast milk has a high lactose content compared to cow’s. ilk. On demand breast feeding may give rise to caries, hence try to discourage it.

Question 58

1.17 a) What is meant by the terms balancing and compensating extractions?

Answer 58

i) Balancing extraction = the extraction of the same or adjacent tooth on the opposite side of the same arch.

ii) Compensating extraction = extraction of same or adjacent tooth in the opposing arch on the same side.

Question 59

1.17 b) What is the likely effect of premature loss of a deciduous canine?

Answer 59

i) The primary effect of early loss of deciduous teeth in a crowded mouth is localised crowding.

ii) The extent with depend on several factors, including the patient’s age, extent of existing crowding and the site of the early tooth loss.

iii) In crowding, adjacent teeth will move into the extraction space, hence a centreline shift will occur with the unilateral loss of a deciduous canine.

Question 60

1.17 c) Is the effect (centre line shift) greater or less with the premature loss of a deciduous first molar than with a canine?

Answer 60

i) A centreline shift will occur to a lesser degree with the unilateral loss of a deciduous first molar compared with a deciduous canine.

Question 61

1.17 d) What would you recommend in a crowded mouth requiring the unilateral loss of an upper canine?

Answer 61

i) The unilateral loss of a canine should be balanced as the correction of a centreline discrepancy is likely to need a fixed appliance and prevention is preferable to dealing with the problem.

Question 62

1.17 e) What is the effect of premature loss of deciduous second molars?

Answer 62

i) The premature loss of deciduous second molars is associated with forward migration of the first permanent molars. This is greater if the deciduous second molars are lost before eruption of the first permanent molars, so if possible, delay extraction of deciduous molars until the first permanent molars are in occlusion.

Question 63

1.17 f) Do you compensate or balance the premature loss of deciduous second molars?

Answer 63

i) Neither

Question 64

1.18 a) An anterior open bite can occur with which types of malocclusion?

Answer 64

i) It can occur in Class I, Class II or Class III malocclusions.

Question 65

1.18 b) Give a simple classification of the causes of an anterior open bite.

Answer 65

i) Skeletal causes:
(1) Increase in lower anterior face height (increased lower face height or increased maxillary to mandibular plane angle)
(2) Localised failure of alveolar growth

ii) Soft tissue causes:
- Endogenous tongue thrust

iii) Habits:
- Digit sucking

Question 66

1.18 c) An anterior open bite caused by one factor is relatively straightforward to treat. Which factors is this?

Answer 66

i) Digit sucking

Question 67

1.18 d) What other occlusal features may you see in this situation?

Answer 67

i) Retroclined lower incisors
ii) Proclined upper incisors
iii) Unilateral buccal segment crossbite with mandibular displacement.

Question 68

1.18 e) How will you treat an open bite due to the digit sucking?

Answer 68

i) Best not to make a big fuss about digit sucking. Most children will grow out of the habit and the malocclusion usually corrects itself after several years. However, if there are other aspects of the malocclusion that need treatment, this should not be delayed. Various appliances may help to break the habit.

Question 69

1.19 a) Name 5 ways in which fluoride is administered to children? (8)

Answer 69

i) General water supply
ii) Milk e.g. school milk schemes
iii) Salt
iv) Toothpaste
v) Gel
vi) Varnishes
vii) Rinses
viii) Tablets

Question 70

1.20 a) What are the different types of vital pulp treatment for deciduous teeth? Briefly describe the indications, the rationale and the clinical procedure for each of the treatments. How would you restore a tooth that had undergone a pulpotomy?

Answer 70

i) Indirect pulp treatment
(1) Indications:
(a) Tooth with a deep carious lesion
(b) No signs or symptoms indicative of pulpal pathology
(2) Rationale:
(a) To arrest the carious process and provide conditions conducive to the formation of reactionary dentine beneath the stained dentine and remineralisation of remaining carious dentine.
(b) To promote pulpal healing and preserve/maintain the vitality of pulp tissue.
(3) Procedure
(a) Removal of all caries at the enamel-dentine junction.
(b) Judicious removal of soft deep carious dentine lying directly over the pulp region with care to avoid a pulpal exposure.
(c) Placement of appropriate lining materials such as reinforced glass ionomer cement, a hard-setting calcium hydroxide or zinc oxide eugenol.
(4) Clinical outcome:
(a) >90% clinical success (absence of symptoms or pathology) at 3 years’ follow-up.

ii) Pulpotomy (vital)
(1) A pulpotomy entails the removal of the coronal pulp and maintenance of the vitality of the radicular pulp.
(2) Rationale
(a) To remove the coronal pulp, which has been clinically diagnosed as irreversibly inflamed, leaving behind a possibly healthy or reversible inflamed radicular pulp.
(3) Procedure:
(a) Removal of caries
(b) Complete removal of root of pulp chamber
(c) Removal of coronal pulpal tissue with sharp sterile excavator or large round bur in a slow handpiece
(d) Attain initial radiocular pulpal haemostasis by gentle application of sterile cotton pledget moistened in saline
(e) Apply medicament directly to radicular pulp stumps (any of the following):
(i) 15.5% ferric sulphate solution
(ii) MTA paste applied over radicular pulp
(iii) Well condensed layer of pure calcium hydroxide powder applied directly over radicular pulp
1. Application of a lining (if appropriate) such as reinforced glass ionomer or zinc oxide eugenol cement.
(f) Definitive restoration
(i) You would usually restore a tooth that had undergone a pulpotomy with a stainless steel crown.

Question 71

1.20 b) When would you carry out a desensitising pulp therapy and when would you carry out a pulpectomy? Briefly describe the clinical procedure to perform each technique.

Answer 71

i) The aim of a desensitising pulp therapy is to reduce pulpal inflammation and/or symptoms in order to facilitate subsequent pulpotomy or pulpectomy procedure. You would consider it in a tooth with a carious exposure but no signs/symptoms of loss of vitality or in a non-competent child, or in the case of a hyperalgesic pulp (adequate analgesia not achieved.

ii) A pulpectomy involves the removal of irreversibly inflamed or necrotic radicular pulp tissue and cleaning of the root canal system. Following this the root canals are obturated with a filling material that will resorb at the same rate as the primary tooth and be eliminated rapidly if accidently extruded through the apex. It is used in a compliant patient when a tooth is diagnosed as having irreversible pulpitis or a non-vital pulp with or without associated infection.

iii) Desensitising pulp therapy:
(1) Procedure:
(a) Removal of caries
(b) Place a small pledget of cotton wool with steroidal antibiotic paste (Ledermix) directly over exposure site (tooth is usually too sensitive to remove entire root of pulp chamber).
(c) Place a well-sealed temporary dressing over the cotton pledget.
(d) Proceed with a pulpotomy or pulpectomy technique (depending on clinical findings after 7-14 days).
(e) The success rate for the use of Ledermix as a pulpotomy agent in primary teeth is not well documented and hence this is reserved for cases where good anaesthesia cannot be achieved or there is initial poor pt compliance.

iv) Pulpectomy:
(1) A one- or two- stage pulpectomy may be undertaken depending on whether the radicular pulp is irreversibly inflamed or non-vital. If infection is present, and the presence of an exudate does not allow drying of the canal, consideration should be given to the two-stage pulpectomy technique, where the root canals may be dressed with an antimicrobial agent for 7-10 days and subsequently obturated at the second visit.
(2) Procedure:
(a) Removal of roof of pulp chamber
(b) Removal of any remains of coronal pulp tissue.
(c) Not whether radicular pulp is bleeding (one-stage procedure) or necrotic (usually requiring two-stage procedure).
(d) Identify root canals
(e) Irrigate with normal saline (0.9%), chlorhexidine solution (0.4%) or sodium hypochlorite (0.1%)
(f) Estimate working lengths of root canals keeping 2mm short of the radiographic apex
(g) Insert small files and file canal walls lightly and gently.
(h) Irrigate the root canals.
(i) Dry canals with pre-measured paper points, keeping 2mm form root apices.
(j) If infection present (canal exudate and/or associated sinus) dress root canals with non-setting calcium hydroxide and temporise (two-stage procedure). Consider prescribing a systemic antimicrobial.
(k) If canals can be dried with paper points, obturate root canals by injecting of packing a resorbable paste, e.g. slow-setting pure zinc oxide eugenol, non-setting calcium hydroxide paste or calcium hydroxide and iodoform paste (Vitapex or Endoflas).

Question 72

1.21 a) Fill in the gaps: The maxilla is derived from the …A… pharyngeal arch and undergoes …B… ossification. Maxillary growth ceases …C… in girls than in boys. The mandible is derived from the …D… pharyngeal arch and is a membranous bone. The mandible elongates with growth at the condylar cartilage, at the same time bone is laid down at the …E… vertical ramus and resorbed on the …F… margin. Mandibular growth ceases …G… than maxillary growth and is …H… in girls than in boys.

Answer 72

i) A = first
ii) B = intramembranous
iii) C = earlier in girls than in boys (15 years girls and 17 years boys)
iv) D = first
v) E = posterior
vi) F = anterior
vii) G = earlier
viii) H = earlier in girls (average 17 years in girls and 19 in boys).

Question 73

1.21 b) What is the difference between endochondral and intramembranous ossification? Give an example of where each occurs in the head.

Answer 73

i) Endochondral ossification occurs at cartilaginous growth centres where chondroblasts lay down a matrix of cartilage within which ossification occurs. This occurs at the synchondroses of the cranial base.

ii) Intramembranous ossification is the process in which bone is both laid down with fibrous tissue, there is no cartilaginous precursor. This occurs in the bone of the vault of the skull and the face.

Question 74

1.22 a) List two localised (3) and three generalised causes (7) of abnormalities in the structure of enamel?

Answer 74

i) Localised causes
(1) Infection
(2) Trauma
(3) Irradiation

ii) Generalised causes:
(1) Amelogenesis imperfecta
(2) Infections: prenatal (rubella, syphilis); postnatal (measles)
(3) At birth: premature birth, prolonged labour
(4) Fluoride
(5) Nutritional deficiencies
(6) Down syndrome
(7) Idiopathic

Question 75

1.22 b) What do you understand by the term enamel hypoplasia and how dies it differ from hypocalcification?

Answer 75

i) Hypoplasia is a disturbance in the formation of the matrix of enamel which gives rise to pitted and grooved enamel.
ii) Hypocalcification is a disturbance in mineralisation (calcification) of the enamel and gives rise to opaque white enamel.

Question 76

1.22 c) Name three disturbances of dentine formation. (8)

Answer 76

i) Dentinogenesis imperfecta
ii) Dentinal dysplasia type I and II]
iii) Fibrous dysplasia of dentine
iv) Regional odontodysplasia
v) Ehler-Danlos syndrome
vi) Vitamin D resistant rickets
vii) Vitamin D dependent rickets
viii) Hypophosphatasia

Question 77

d) What do you understand by the term Turner teeth?

Answer 77

i) This is caused by infection from a deciduous tooth affecting the developing underlying permanent tooth. It results in abnormal enamel and dentine.