SAQs for Dentistry Flashcards
Name 2 conditions that may result in delayed eruption of primary teeth.
- preterm birth
- chromosomal abnormalities (e.g: down syndrome)
- nutritional deficiency
- hereditary gingival fibromatosis
(hypothyroidism is also a systemic condition which may cause this)
Hypodontia is more common in which dentition?
permanent dentition (more common in females)
Define infraocclusion.
Submerged teeth - teeth which fail to maintain their occlusal relationship with the opposing teeth.
What are the 3 grades of infraocclusion?
grade 1 - occlusal surface is above the contact point of the adjacent tooth.
grade 2 - occlusal surface is at the contact point of the adjacent tooth.
grade 3 - occlusal surface is below the contact point of the adjacent tooth.
Which tooth is most commonly affected by infraocclusion?
deciduous mandibular first molars
A fit and healthy 12 year old girl attends with her mother following an accident. She has banged both her upper anterior teeth. Examination reveals no EO injuries but both the upper centrals are mobile and crowns are palatally displaced.
What special tests would you carry out?
- vitality testing of all upper and lower incisors
- PAs and upper standard occlusal to see if the roots have fractured
What is the immediate treatment for a mid-third root fracture in the upper centrals of a 12 year old.
Flexible splint for 4 weeks.
What treatment would be carried out if the coronal segment became non-vital?
Pulp should be extirpated to the fracture line and filled with non-setting CaOH, monitor.
Name 3 types of non-pharmaceutical behavioural management in children.
- tell, show, do
- distraction
- positive reinforcement
Which drug is commonly used in inhalation sedation?
nitrous oxide
Give 2 contraindications for the use of Nitrous Oxide (IHS).
- sickle cell disease
- COPD or any respiratory tract infection
- a cooperative patient
- first trimester of pregnancy
What types of appliance are the Andresen, Frankel and twin block appliance?
How do they work?
functional appliances -
orthodontic appliance which utilises the forces generated by orofacial musculature, tooth eruption and facial growth to correct malocclusion.
Which type of malocclusion is most successfully treated with a functional appliances?
Class II - especially class II div 1 (incisors stick out)
What age group of patients are functional appliances most effective in?
Growing children, particularly before their growth spurt.
Skeletal changes from using functional appliances:
- restraint or redirection of forward maxillary growth
- optimization of mandibular growth
- forward movement of glenoid fossa
- increase in lower facial height
Dental changes from using functional appliances:
- palatal tipping of upper incisors
- labial tipping of lower incisors
- forward movement ox maxillary molars inhibited
- medial and vertical eruption of maxillary molars
Think back to GCSE physics, what determines the response of a tooth when a force is applied to it?
the duration and magnitude of the force.
What are some common complications of orthodontic treatment?
- recession
- gingivitis
- trauma / ulceration from attachment
- allergy from attachments (e.g: nickel)
- relapse
- incomplete treatment
- loss of vitality
- pt disatisfaction
With regards to the IOTN aesthetic component, what are the different treatment need classifications vs score?
(only taken into account if DH component is 3 because 4-5 indicates treatment need anyway)
1-2: no treatment
3-4: slight need
5-7: moderate / borderline need
8-10: definite treatment need
What may cause a midline diastema?
- normal development
- missing teeth
- midline supernumerary / odontome
- prominent frenum
Which developmental anomalies may occur with a patient who has cleft lip and palate?
- hypodontia
- delayed eruption
- hyperdontia
- hypoplasia
What are the effects of fluoride prior to eruption?
- teeth have more rounded cusps and shallower fissures
- crystal structure of enamel is more regular and less acid soluble.
What are the effects of fluoride after eruption?
- decreases acid production from bacteria - inhibits growth and glycolysis.
- prevents demineralization and encourages remineralisation
- the remineralized enamel is more resistant to acid attacks
Why is fluoride usage contraindicated until 6 months old?
Because infants don’t have adequate renal function to excrete fluoride
What is a balancing extraction?
The XLA of the same / adjacent tooth on the opposite side of the same arch.
What is a compensating extraction?
XLA of the same or adjacent tooth in the other arch on the same side.
What are 2 common causes of an AOB?
- tongue thrust
- digit sucking
Which pharyngeal arch is the maxilla derived from?
first
In which sex does maxillary growth cease in first?
girls
Which pharyngeal arch is the mandible derived from?
first (same as the maxilla)
Mandibular growth classes later than maxillary growth and occurs earlier in which sex?
girls
Localised causes of enamel abnormalities.
- trauma
- infection
- irradiation (radiotherapy)
Generalized causes of enamel abnormalities.
- amelogenesis imperfecta
- infections such as measles, rubella and syphilis
- premature birth
- fluoride
- nutritional deficiencies
- down’s syndrome
(may also be idiopathic - unknown cause)
hypoplasia vs hypocalcfication
hypoplasia - disturbance in the matrix formation of enamel, causes pitted / grooved enamel.
hypocalcification - disturbance in mineralisaion of enamel, causes opaqueness.
Causes of intrinsic discoloration.
- trauma resulting in plural death
- fluorisis
- tetracycline staining
- amelogenesis imperfecta
- dentinogenesis imperfecta
What is primary dentine?
Dentine formed before eruption or within 2-3 years after.
What is secondary dentine?
Regular dentine formed during the line of the tooth - laid down on the floor and ceiling of the pulp chamber.
What is tertiary dentine?
reparative - irregular, laid directly beneath the path of injured dentinal tubules in response to stronger stimuli.
reactionary - laid down in response to mild stimuli.
Where does internal resorption start?
Within the pulp chamber of VITAL TEETH ONLY.
Where does external resorption start?
On the surface of the tooth - most commonly on the root surface.
VITAL OR NON-VITAL TEETH.
How can you tell if a tooth is ankylosed?
- metallic sound on TTP
- no PDL space on radiograph
- no mobility
- may become infraoccluded
Define pulpits.
inflammation of the pulp.
Define reversible pulpitis.
A short pain form hot/cold stimuli, poorly localized and lasts for a few seconds.
Define irreversible pulpits.
A throbbing pain set off by biting or spontaneously, well localized and lasts for longer.
Types of nerve fibers found in the pulp.
A Beta - large, fast conducting proprioceptors.
A Delta - small, sensory fibers.
C - small, unmyelinated sensory fibers.
Describe the Hydrodynamic theory.
Exposed dentine tubules are disturbed by changes in temperature, causing movement of the fluid within them. This movement disturbs nerve endings in the pump-dentine complex (especially A delta fibers) which results in a sharp localized pain.
How do desensitizing agents help to reduce dentine sensitivity?
By occluding the tubules, desensitizing nerves and preventing further exposure.
Define microleakage.
The passage of bacteria, fluids, molecules or ions through the walls of a restoration.
Consequences of microleakage.
- discoloration
- secondary caries
- pulpal pathology
Define ‘Smear Layer’.
Tooth tissue debris from preparing the cavity that has been smeared over the tooth surface - it is a contaminant that prevents bonding of restorative materials.
What can be used to remove the smear layer prior to bonding and restoration placement?
37% orthophosphoric acid etch.
(EDTA can also be used although not as strong as etch)
When is removal of the smear layer important?
When placing composite AND glass ionomer restorations and RCT.
What are the aims of obturation?
- prevent reinfection
- seal any remaining bacteria inside the root canal
Causes of RCT failure.
- bacteria left in the root canal system (lateral or accessory canals)
- contamination of the canal during treatment
- lack of coronal seal
- persistent infection after treatment
Indications for an apicectomy.
- infection due to a lesion requiring a biopsy (e.g: radicular cyst)
- instrument stuck in canal with residual infection
- impossible to fill apical 1/3 due to anatomy or pulp calcification (pulp stone)
- perforation of the root
- post crown with excellent margins but persistent PA pathology
- infected, fractured apical 1/3
Define OVD
Occlusal Vertical Dimension
A measurement taken below the nose to below the chin when the patient’s teeth are in occlusion, done with a willis bite gauge.
In which patients is it important to measure the OVD?
When providing a RPD, complete denture or when changing the OVD of a worn dentition.
Define Group Function.
During lateral excursions, there is contact between several upper and lower teeth on the working side and no contacts on the non-working side.
Define Canine Guidance.
Contact between the upper and lower canine on the working side on lateral excursions.
Define Balanced Occlusion.
Simultaneous contacts between opposing artificial teeth on both sides of the dental arch.
Advantages of an immediate denture.
- pt doesn’t have to go without teeth (aesthetic considerations)
- easier to register jaw relations from when the pt had teeth there.
- bleeding easier to control after the XLA
- prevents space loss.
- soft tissue support.
Disadvantages of an immediate denture.
- resorption - dentures may become loose and need to be remade
- no try in stage
- may not fit on the day.
What is a dental surveyor able to identify prior to design?
- the most desirable path of insertion
- areas of undercut (whether they are desirable or need to be blocked out)
- areas for occlusal rests
- areas of retention
What is an articulator used for?
to replicate the relationship and movements of the jaw - casts are mounted on this.
What is the purpose of a face bow?
Measures the relationship of either the maxillary or mandibular arch to the intercondylar axis and is used to transfer these measurements to an articulator.
5 muscles whose movements may affect the peripheral flanges of a complete denture.
- geniohyoid
- obicularis oris
- mentalis
- mylohyoid
- buccinator
- palatopharyngeus and palatoglossus.
Where does the posterior margin of the upper complete denture lie?
anterior to the fovea palatine
What is the function of the post dam?
To compress the soft tissues and form a border seal.
Where does the post dam lie?
At the junction of the hard and soft palate.
In what situation would a copy denture be made?
- occlusal wear on a set of successful complete dentures
- replacement of the base material
- set of dentures the pt was happy with have become worn / unretentive and pt would struggle to habituate to completely new dentures
- to make a spare set
How would you determine the working length of a root canal?
- an apex locator
- working length radiograph with an instrument in the canal
Properties of an ideal root canal material.
- radiopaque
- bacteriostatic (inhibits growth of bacteria)
- biocompatible
- easy to handle and remove if needed
What is an overdenture?
A denture which has its support from 1 or more abutment teeth by completely covering them with its fitting surface (usually retained roots).
In what situations would you do an overdenture?
- preservation of alveolar bone around retained roots
- preserved proprioception
- increased masticatory force
- psychological benefit of not losing all teeth
Patient related factors which may compromise the success of an implant.
- uncontrolled diabetes
- oral hygiene
- periodontal disease
- previous radiotherapy
- smoking
- bisphosphonate treatment
Clinical features of a failed implant.
- suppuration
- crater-like bone loss
- mobility
- pain
(peri-implantitis)
Constituents of dental amalgam.
- tin
- copper
- zinc
- mercury
- silver
Indications for anterior veneers.
- discoloration
- closing of a midline diastema
- hypoplastic teeth
- fracture of teeth
- modifying the shape of a tooth
2 types of material used for veneers.
- porcelain
- composite (direct or indirect)
When are posterior crowns used?
- bridge abutments
- restoring endodontically treated teeth
- fractured teeth
Clinical features of ANUG
- painful ulceration initially involving the interdental papille
- metallic taste
- fever and malaise
- poor OH
Risk factors of ANUG
- smoking
- poor OH
- HIV
- stress
- malnourishment
Define pericoronitis. Which teeth are commonly involved?
Inflammation of the tissue surrounding the crown of a tooth (operculum), commonly impacts lower 8s.
Symptoms of pericoronitis.
depends on severity but ranges from:
- swelling of soft tissue around the crown
- bad taste
- pain
- lymphadenopathy
- EO swelling
Treatment of pericoronitis.
- irrigation
- antibiotics (metronidazole)
- OHI (hot salty mouthwashes)
- analgesics
