Potential Questions Flashcards
What landmarks are used to construct the mandibular and Frankfort planes
- Po to Or
- Go to Me
What angle is used to determine the anteroposterior position of the mandible
- ANB
What angle is used to determine vertical discrepancies
- FMPA angle
Name 3 salivary glands
- Parotid gland
- Submandibular gland
- Sublingual gland
What are the uses of saliva
- chewing , lubrication, digestion,
What are the implications of saliva during orthodontic procedure?
- cleaning, buffering PH level, prevent caries
- Disadvantage- Moisture control
Name the muscles of mastication
- Masseter
- Medial pterygoid
- Lateral pterygoid
- Temporalis
What muscle of mastication is used to open the mouth
- Lateral Pterygoid
What nerve supplies muscle of mastication muscles ?
- 5th Trigeminal nerve
Which of these muscles would ache when a functional appliance is worn
Masseter
What are the effects on the dentition from a digit sucking habit
- Open bite - Unilateral: bilateral displacement
- Anterior open bite.
- Proclined upper incisor
- Retroclined lower incisors
- crossbite with mandibular displacement
What are the factors in the amount of effects that may occur
Skeletal factor - Increased lower face height
Soft tissue - forward tongue posture or atypical swallowing pattern
Habit - digit sucking
Combination of above
For a patient with a Class II div I type malocclusion, what makes trauma more likely
– 45% of 12 yrs old children with OJ > 9mm had visible damage to increased incisor
- More effect of OJ in females than males
- 50% children need tx following trauma.
For a patient who has had previous trauma what might you consider during treatment planning
- No tx
- Explained risk of trauma before tx
- Involved pt and parent with decision
- Shorter treatment length / aim
- Monitoring during tx
- light conts force
If a patient complained about you, what would you do.
- Acknowledge mistake and apologise.
- Listen carefully.
- Explain them what went wrong and put things right quickly and effectively.
What are the effects of using too much force
- If excessive force is applied for prolonged period, the blood flow cut off from PDL and sterile necrosis ( hyalinisation) will result and no osteoclastic stimulation occurs. Bone will remodelled by cells from adjacent undamaged areas this is known as undermining resorption.
Results into : Pain for pt , Slow movement , Root resorption and Ankylosis.
What factors must you consider before you change an arch wire
-Niti - alignment wire flexible shape memory and low constant force
- SS- Rigid, high stiffness, low friction than Niti.
Bodily movement - Niti/ SS rectangular wire 2 point contact
What wire would you use for space closure
- SS round wires for sliding mechanism.
What are the factors that decide the force in an aligning arch wire
- Below capillary pressure 20-25 gm/cm2
What is friction and how would you limit it
- Friction is the force resisting relative motion.
Law- Friction = Force x Coefficient of Friction. - Bracket - material ceramic > friction than metal
- Wire- material - beta titanium > friction than NiTi > friction than SS
- Type of Ligation - Elastomeric ligatures 60-70% more than SS.
- ## Type of tooth movement - Tipping bodily movement
What is informed consent
- A patient must be given full information about what treatment is involved including benefits,
Risks, advantages and disadvantages. Alternatives
to treatment including doing nothing.
How should it be documented
- Contemporaneous
- Informed written consent.
- Signing a consent form with all option, benefit, advantages ,disadvantages given letting them know it’s inform decision.
Name another form of consent
- Implied - Book and turn up for appointment
- Expressed - Either Verbal or writing express they are happy for appt to go ahead with treatment prescribed.
- Informed- Signing consent form with all options, risks, benefits, advantages and disadvantages given letting them know it’s an informed decision.
List 3 helpful aids that could be used when explaining orthodontic treatment to patients
- Photos
- Study model / Digital scan
- Radiographs
- appliances
What should all dental staff be immunised against
- Tetnus
- Hep B
-Hep C - Diptheria
- Polio
- MMR
How many hours of CPD does an orthodontic therapist have to complete
- 75 hours per cycle verifiable.
- Unlimited non verifiable.
What is CPD and why is it necessary
Continuing professional development is defined as learning experiences which help you develop and improve your professional practice.
What 5 things should be documented on an OPT
- Present teeth
-Position of teeth - Pathology- Decay ,’bone level, length of root ,cyst , periodontal disease.
- Clinical Justification
-Optimisation
List 5 things shown on an OPT
- 3P- Position, presence and pathology of tooth
- Bone level
Why do we need retention
- Due to elastic recoil of gingival and PDL fibres.
- For reorganisation of the periodontal and gingival tissue after Orthodontic treatment.
- PDL reorganises over 3months
- Gingival (Collagenous fibres) reorganise over 6month
- Gingival (Supercrestal fibres) reorganise over 1 yr.
Name 2 periodontal fibres and how long it takes them to reorganise
- 3-6months - Supracrestal and collagenous periodontal and
- 1 year transseptal fibres
What would you do if you dropped etch:
On a patients lip
On a patients clothing
In a patients eye
- On lip - Wash, inform pt and apologise. record in notes and incident book. Explain scab can appear but it will heal. Suggest to contact pharmacist if needed. Follow up with pt .
- Patient clothing - remove it and inform pt and apologies.
- Patient eye- Wash immediately and rinse thoroughly. apologise and inform pt and orthodontist, record in accident book. Ask them to get it check asap.
What is the definition of relapse
Reasons for relapse
Types of retainers
- The Return , following correction of original features of malocclusion
- Orthodontic tooth movement results in disruption of periodontal and gingival structures. Because tissue are slow to remodel following orthodontic tooth movement, residual tension with periodontal ligament and gingival fibres results in elastic recoil which moves teeth towards their original position. 3-4 months PD, 4-6 months gingival fibres and 1 year transseptal fibres
- Hawley retainer , Vacuum formed essix retainer and Fixed bonded retainer.
What is iotrogenic damage
List 2 benefits of orthodontic treatment
List 3 risks of orthodontic treatment
- Tissue or organ damage that’s caused by necessary medical treatment
- Improves OH , Aesthetic, and function
- Root resorption, relapse , decalcification.
What causes a splinter haemorrhage
Who would you consult with regarding this
What should healthcare workers be vaccinated against
Name 2 blood borne viruses
What virus could you catch with an ungloved hand
What is the most common metal allergy.
- Bacteria endocarditis and scleroderma
- GP
- Tetnus, Polio, diptheria, MMR (Measles,mumps and Rubella).
- Hepatitis B, Hepatitis C, HIV.
- Hep B, Hep C?
- Nickel
What are the 3 fibres contributing to ortho relapse
How long does it take for the elastic fibres to remodel
What effect do 3rd molars have on stability
What 3 factors are important in stability
- Periodontal fibre , Gingival fibre and Transseptal fibre.
- Periodontal fibre 3-4 months, (Collagenous fibre ) 4-6 months and (Supercrestal fibres)Transseptal fibre 1 year
- No outcome. Some says cause mandibular anterior crowding occurs
- Periodontium, soft tissue, growth and occlusion.
What causes an open bite
What treatment would you advise
1 - High FMPA angle ,backward growth rotation
- Habit- Tongue thrust
- aitrogenic - Extrusion of molars
- Trauma- effecting condyle
- Pathology- CLP
- Respiration
2- Stop habit , Orthodontic approach, Orthognathic approach or both
Define anchorage
List 3 ways to increase anchorage in a fixed appliance system
What happens if excessive force is applied
How long does force need to be applied before movement
When headgear is used for anchorage what is the force and duration
- Resistance of unwanted tooth movement.
- Increased number of teeth to anchor unit by increasing root surface area. Restrict anchor unit to move and maximise wanted tooth movement and minimise unwanted tooth movement.
-If excessive force is applied direct resorption of the bone doesn’t occur due to compression of blood vessels, ground glass appearance hyalinisation occurs Sterile necrosis. Indirect root resorption (undermining root resorption) occurs once pressure is released. - Light constant force for more than 6hours
- Anchorage 250-300g per side 10-12 hours
What is meant by ‘Duty of Care’
What is informed consent
Who can give consent for a pt under the age of 16
Who can give consent to a handicapped pt over the age of 16
How long are we legally required to keep pt records
- be honest and open to patient if something goes wrong
- informed consent means patient and parent has been informed verbally and written about all tx options, benefits and risk included including no tx option.
- anyone who is under age of 16 has mental capacity to understand information and take decision.
- parent or legal guardian
- Till age of 25 and 11 years
What is the risk of inducing cancer when taking a ceph
What is the effective dose of an OPT
What information can be obtained from a ceph
Name the usual planes drawn on a ceph tracing and what landmarks are needed to do so
- risk is very less but unnecessary radiation from diagnostic Radiographs cause 200-250 uk cancer fatalities. 25% of all X-rays are dental examination xray.
- -< 3 uSv Sievert Ceph
- It is reproducible radiographs of lateral Skull to assess facial, dental and skeletal relationship in vertical and anterior posterior dimensions.
- Frankfort plane - Or-Po
- Sn plane - Sella to Nasion
- Maxillary plane - Ans -
Mandibular plane - Go- Me
Name the 4 components of a URA
What type of movement can be obtained with a URA
What functional appliance allows eruption of the buccal segments
Name 2 ways of transitioning from a functional to FA
What muscles are utilised during functional therapy
What proportion of the effects are dental and skeletal
ARAB- Active - anterior / posterior bite plane Spring 0.5mm (Retentive - Southend 0.8mm Elgiloy 0.7mm ss , Labial bow 0.7mm Adams’s 0.6 mm crib Anchorage - palatal vault, root surface area, extra oral. Base plate- Completed,segmented ,buccal capping.
- Tip teeth around fulcrum at centre of resistance.
- bite planes ?
- Trimming / undermining blocks.
- A period of nights only wear after overjet reduction - usually 3 months
- When overjet reduced, place URA with very steep anterior bite plane to reduce overbite and hold mandible and lower incisor forward.
- Subsequent fixed appliances
- Muscle of mastication
- facial muscles
- Oro facial
- 70% dental 30% skeletal
Describe a Class I molar relationship
Name 2 common presenting features of a Class I malocclusion
Describe a Class II div I incisor relationship
What is the aetiology of a Class II div I malocclusion
Nmae Andrews 6 keys
- Crowding and Bimaxillary proclination
- Sk Class 2 relationship, Habit - Thumb sucking, Soft tissue- Lower lip trap behind upper incisors,short upper lip.
- Correction of molar relationship, correction of inclination of teeth, correction of angulation of teeth, flat curve of spee, no rotation, no space.
What is COSHH
What are the 7 steps of hazardous substances
- The Control of Substances Hazardous to Health.
- Conduct a COSHH risk assessment
- Eliminate any risks
- Implement control measures
- Review control measures
- Develop emergency procedures
- Monitor workplace exposure levels
- Conduct health surveillance
-Provide information and training
Give 3 examples of the effects of hazardous substances
What would you do if you dropped etch on a pts lip
- Irritant, Skin damage and dizziness
- inform pt duty of candour. Be apologetic by mean, explain what can happen and how to manage it and follow up with it, document Contemporaneous notes and incident book.
Name 5 ways to isolate for a bond up
What type of etch is used
What 4 things does etch do
- Cheeck retractors, suction, cotton rolls, dry guard, saliva ejector.
- Phosphoric acid 20-35% apply for 15-30 seconds.
- to Increase surface area for bonding by increasing surface area.
What chemical is unfilled resin
Why is resin used
What does the light do
Q-List the advantages and disadvantages of direct and indirect bonding
Q-What is the difference between the 2
- Methyl methacrylate monomer
- To protect etched surface
- Polymerisation- the process of converting a liquid monomer or prepolymer into a solid polymer by a polymerization reaction when irradiated by UV or visible light
- -
What is meant by intra arch and gives examples
What is meant by inter arch and give examples
- Intra arch- Same arch - Rotation, space, crowding of teeth.
- Inter arch- both arch - increased or decreased Overjet, increased or decreased overbite cross , scissor bite.
Where should a bracket be placed
What does a SWA provide
Where should a buccal tube be placed
What is the molar relationship if:
Upper first premolars have been extracted
Lower first pre molars have been extracted
All first premolars have been extracted
No premolars have been extracted
- LA point of LACC precise position.
- SWA- single wire appliance provide 3 order movement build in bracket.
- Buccal tube should be placed on Buccal midpoint of molar.
- Upper premolars- Class 2
Lower premolars- class 3
-All 4- Class 1. - No Xtn. Class 1
List 3 ways of treating a skeletal problem
Q-What might happen to lip support if dental camouflage is used
What are the dental changes produced in functional therapy
- Orthdontics alone , Orthognathic alone or both.
- incompetent lip may result relapse of tx like corrected overjet increased
- Proclined lower incisors
Retroclined upper incisors
Mesial movement of lower buccal segment
Distal movement of upper buccal segment
What are the consequences of the following bracket position errors:
Bracket is not seated correctly (wedge of material)
Bracket is too high or too low on the tooth
Bracket is tipped on the tooth
Bracket is placed too mesially or too distally
- Bracket will not deliver prescribed movement.
High - Intrusion . Low Extrusion
Tipped - wrong tip to tooth mesioangulate disto-angulate
Too mesially or distally - Rotate tooth
How would you monitor anchorage
- 3 dimensional assesment, note and photos and study model.
AP- loss of space with increased OJ - Vertical- High buccal canine to come down.
- Lateral - canine palatal impacted with cross bite.
Wha things does etch do
- Expose enamel prism to increase surface area by increasing surface area
List 3 ways to create space
- distalising
- IPR
- Proclining lower incisors
- Expansion
- extractions
Who can consent to treatment for a pt who is handicapped and over the age of 16
Parent, legal guardian or carer
List three ways of increasing anchorage in a fixed appliance
- Vertical - IO elastics
- AP - bonding / banding 7s ,TPA ,
Heaadgear. - Nance
- Moving anchor unit difficult.
- Making other teeth move easy
Briefly describe how a functional works
- They are constructed to posture the mandible forward and away from rest position. As a resultant soft tissue stretch generate forces that causes tooth movement.
What are the skeletal and dental effects
- Skeletal - Retrain maxilla growth by 1-2mm
Enhance mandibular growth by 2-3mm - Procline lower incisors
Retroclined upper incisors
Medial movement of upper buccal segment
Distal movement of lower buccal segment
Define anchorage
- Source of resistance to forces generated in reaction to the active components of appliance. This is Newton third law for every action there is an equal and opposite reaction.
What is meant by the term ‘Duty of Care’
Being open and honest with patient Before tx
What is informed consent
Informed - signing consent form with all options risks, benefits, advantages disadvantages, given and letting them know or it’s inform consent.
Name and define all ceph landmarks
-(A) Deepest concavity on anterior profile of
maxilla
(B) Deepest concavity on anterior surface of
mandibular symphysis
Anterior nasal spine (ANS)
Tip of anterior process of maxilla
Posterior nasal spine (PNS)
Tip of posterior nasal spine of maxilla
Pogonion (Pg)
Most anterior point on bony chin
Nasion (N)
Deepest point on frontonasal suture
Sella (S)
Midpoint of sella turcica
Orbitale (Or)
Most inferior point on orbital margin
Porion (Po) Upper and outermost point on bony external
auditory meatus
Condylion Most superior posterior point on the
condylar head
Gnathion (Gn) The most anterior inferior point on the
mandibular symphysis
Menton (Me)
Lowest point on mandibular symphysis
Gonion (Go) The most posterior inferior point on the
angle of the mandible
What are Andrews 6 Keys
- Correction of molar relationship
- Correctoon of crown inclination
- Correction of crown angulation
- Flat curve of spee
- No rotation
- No space
What is meant by 1st, 2nd, and 3rd order
1st order - in/out
2nd order- crown tip
3rd order- crown torque
What are intra and inter arch relationships and give examples of each
- Intra - Same arch - Crowding, spacing, rotation
- Inter- Opposite arch- Overjet, overbite, crossbite, scissor bite.
Name 3 standardised things on a ceph
- Assesment of skeletal, dental and soft tissue relationships in ap and vertical directions
What information is obtained from a ceph
- Assess skeletal , dental and soft tissue relationship in AP and vertical dimension.