Ortho questions Flashcards
Name methods to prevent decalcification other than FV?
- Careful case selection
- fissure sealants
- fluoride supplements ( tablets , drops)
- fluoride mouthwash 225ppm
- High strength fluoride toothpaste
- OHI - correct toothbrushing and use of interdental brushes beneath wire and around brackets 2x daily
- Diet advice
- Regular hygiene appointments
List 8 other potential risks of orthodontics other than decalcification?
- relapse
- root resorption
- gingival recession
- trauma
- failure to complete treatment
- ulceration
- TMJ problems
- Risk of periodontal disease
- wear of adjacent teeth
- loss of periodontal support and vitality
- mucosal irritation
How would you assess a patient anterior-posterior relationship?
- visually with Frankfort plane parallel to floor
- Palpate skeletal bases at at two points (upper , lower)
- By lateral cephalometry - SNA - SNB = ANB
What are the classes of AP relationships?
- Class 1 - maxilla 2-3mm in-front of mandible (ANB 2-4)
- Class 2 - maxilla more than 2-3mm infront of mandible (ANB more than 4)
- Class 3 - mandible infront of maxilla (ANB less than 2)
Name 4 special investigations an orthodontist would do?
- Clinical photographs
- Study models
- Radiographs - OPT , lateral ceph
- Sensibility testing
Class 3 incisor relationship definition?
- Lower incisors edge lie anterior to the cingulum plateu of the upper central incisors
- Overjet is reduced or reversed
Name 8 intra-oral features of a class 3 malocclusion?
- reduced overbite , AOB may be present
- Posterior buccal or anterior crossbite
- reverse overjet
- maxilla often crowded
- mandible often aligned or spaced
- proclined upper incisors
- retroclined lower incisors
- tendency for displacement upon closing
What systemic disease causes the mandible to grow?
Acromegaly
How is a Class III malocclusion managed?
- Accept and monitor - if mild and pt still developing
- interceptive ortho URA - correct incisor relationship
- Growth modification ( functional appliance , headgear with RME to reduce and redirect mandibular growth , TAD’s)
- Camouflage - accept underlying skeletal base and correct incisors to class I
- Combined orthognathic and orthodontic treatment to correct functional and appearance issues
What functional appliances can be used for class III relationship?
- reverse twinblock
- frankel III
- chin up
Pt with anterior cross-bite
When is it best to begin ortho treatment?
Intercept as soon as detected with URA
Anterior crossbite involving 21
What featured of the malocclusion makes it suitable for treatment with a URA?
- Tooth in cross-bite is palatally tipped
- Good overbite (aids stability)
- Adequate space to move the teeth forward
Design a URA for fixing an anterior crossbite involving 21?
A - z spring on UR1 0.5 HSSW
R - adam’s clasp 16,26 0.7 mm HSSW + URd , ULd 0.6mm HSSW
A - only moving one tooth
B - selfcure PMMA with FPBP
URA for posterior cross bite
A - midline palatal screw
R - 16 + 26 + 24 + 14 adam’s clasp 0.7mm HSSW
A - reciprocal anchorage
B - self cure PMMA - posterior bite plane
URA for retracting canines
A - Palatal finger spring + gaurd ; 0.5mm HSSW
R - 6s adam’s clasp , 11+ 12 south end clasp 0.7mm HSSW
A - only moving 2 teeth
B - self cure PMMA
URA for moving canines palatally
A - buccal canine retractor + tubing
R - adam’s and south end clasp
A - y
B - selfcure PMMA
URA for overbite
A - robert’s retractor with I.D tubing
R - adam’s clasp 6s
A - y
B - self cure PMMA with anterior bite plane OJ +3mm
What syndromes are associated with hypodontia?
Cleft lip and palate
Axenfeld-rieger syndrome
Ectodermal dysplasia
Down’s syndrome
How may hypodontia present to you as a GDP?
- delayed or asymmetrical eruption
- retained or infra-occluded deciduous teeth
- Ectopic canines
- Absence of decidious teeth
- tooth malformation
Name members of MDT involved in treating hypodontia?
- othodontist
- restorative dentist
- paediatric dentist
- speech and language therapise
- Clinical psychologist
- Oral surgeon
- GDP
What factors can make early loss of primary teeth worse?
- Age of patient - early extraction is worse as will lead to premature eruption of permanent teeth
- space loss
- losing the E’s lead to issues with position of 6
- If it occurs in the maxilla its worse as more space is lost in upper than lower
- in crowded arches lead to evident space loss
- If it is in the anterior teeth will lead to psychological consequences affect appearance
When might you consider a balancing extraction of a primary tooth?
- balancing extractions are extraction of the same tooth in the same arch , this is to avoid centrelines shiftor relieve crowding
- Primary canines for centreline shift
- First primary molars for crowding
Give 4 reasons for an unerupted 1?
- supranumerary teeth (tuberculate)
- Trauma to A
- Crowding
- Pathology - dentigerous cyst
- Ankylosis
- Genetics
What are the treatment options for an impacted 11?
- Accept and monitor
- Surgical exposure and bonding using gold chain (over age of 9) using orthodontic traction
- XLA of supernumerary teeth if present
- Surgical extraction of 11
What is the BSI definition of Class II div 1 ?
- The lower incisor edges lie posterior to the cingulum plateau of the upper incisors
- Increased Overjet
- Upper incisors proclined or of average inclination
What dental features are seen in class II div 1 patients?
- proclined upper incisors or of average inclination
- Increased OJ
- Class 2 molars and canines
- overbite varies
- parted lips may lead to dry gingivae and can exacerbate gingivitis
What soft tissue features are associated with Class II div 1 patients?
- Incompetent lips due to incisor or skeletal relatoinship
- difficulty to achieve an anterior oral seal
- May have lip trap or tongue thrust
What are the 6 features of a twin-block appliance?
- consist of two separate bite blocks
- can have an expansion screw to widen the maxilla
- Has a anterior bow
- Adam cribs on teeth
- removable
- worn for 9-18 months
- deterrent rake can be added to prevent NNSH ( non - nutrusive sucking habit)
- can be adjusted to accommodate any changes
- have an interlocking mechanism
- tooth borne
How long should a twin block be worn for?
9-18 months
What makes a class II div 1 ammedable to correction with a functional appliance?
- Very mild class II
- Overjet is due to proclined or spaced incisors
- There is a favourable overbite
- only after specialised assessment
Usually URA have a very limited role in the treatment of inc overjet
How is the mandible postured when wearing a functional appliance?
- forward and downward
What are the treatment options for class 2 div 1
- accept and monitor
- Growth modification :twin block, frankel II , headgear or herbst
- URA - limited use but can use robert retractor
- fixed appliances
- Orthognathic surgery - when growth is complete and in severe cases
What is dentoalveolar compensation?
- A system the maintain normal inter-arch relationship by the mouth anatomical structures
- normal occlusion can normally be maintained by dento-alveolar compensation
Example of dentoalveolar compensation in class III malocclusion
Tongue Procline upper incisor
Lower lip Retrocline lowers
What 4 special investigations are done for class III patients?
- study models
- clinical photographs
- radiographs : lateral ceph ; OPT ; CBCT
- Planning models (Kesling) : setting up teeth to desired occlusion with wax
- sensibility testing
Define supernumerary teeth
- Tooth or tooth like entity found in the mouth which is additional to the normal series
What is the incidence of supernumerary teeth?
- most common in males
- found in anterior maxilla mostly
- 1% in primary and 2% in permanent
What are the types of supernumerary teeth?
- Conical
- Tuberculate
- Supplemental
- Odontome
What is a conical supernumerary?
- small peg shaped tooth
- close to midline
- Usually 1 or 2 in number
- May erupt but tend to prevent eruption
- May be high, inverted and symptoms free
What is a tuberculate supernumerary?
- Often paired and barrel shaped
- most common caused of failure of eruption of upper incisors
- Tend to not erupt
- need to be extracted
What is supplemental supernumerary?
- extra teeth of normal morphology
- usually an upper lateral or lower incisor
- can be 3rd premolar or 4th molar
- Often extracted due to form and position
What is an Odontome supernumerary tooth?
- Irregular mass of dental hard tissue
- can be compound which are discreet denticles
- can be complex as disorganised mass of dentine, pulp and enamel
What are 6 effects of supernumeraries on the permanent dentition?
- Diastemas
- Impaction (tuberculate cause impaction of 1)
- Displacement (crowding/spacing)
- Cyst formation
- Root resorption of surrounding teeth
- Crowding
What is mandibular displacement on closing?
- occurs when there is an inter-arch width discrepancy
- resulting in upper and lower teeth to meet cusp to cusp
- resulting in the mandible to be deviated to one side upon closing to achieve intercuspal contact position
Why would you correct a mandibular displacement?
- May cause TMD (best to intercept early)
- Tooth wear can occur
- May cause facial asymmetry
- May cause centrelines shift
- Teeth erupt in displaced ICP position
What would you use to correct a unilateral posterior crossbite?
- maxillary expansion with :
URA
Quadhelix
rapid maxillary expansion
Design a URA for someone with unilateral posterior crossbite
A - midline palatal screw 0.5 HSSW
R - Adam’s clasp on 6s and 4s or ds 0.7 HSSW (0.6 for primary)
A - reciprocal anchorage
B - Self cure acrylic + FPBP (must incorporate all posterior teeth to prevent unwanted tooth eruption)
Child present with ulceration , what 8 questions would you ask?
- where is the ulceration?
- is it getting better or worse?
- when did it appear?
- is there any blisters associated ?
- have these symptoms happened before?
- Is there any other area affected?
- Are there any other symptoms?
- Any other associated skin lesions?
- Any symptoms on the lips?
Patient present with ulcers on the lips what should you see intraorally ?
Herpes simplex primary infection
* Painful Erythmatous Swollen Gingivae
* Ulcers on lips, Gingivae and Extraoral mucosa
* Halitosis
Herpes labialis
* only present Extra-orally
Give uses of URA other than tipping and tilting of teeth
- Reduce overbite, overjet and crossbite
- Habit breaker
- Space maintainer
- Used as a retainer (HAWLEY)
- Expanding the arch
Write a prescription for URA to reduce a 6mm overjet and reduce overbite
ex question :
Write a prescription for a URA to reduce a 6mm OJ
1st premolar have been extracted and previous URA retracted canines and reduced the overbite , pt has permanent dentition
A - Robert’s retractor with I.D tubing 0.5mm HSSW
R - Adam’s clasp on 16,26 - 0.7mm HSSW , Stops mesial of 23,13 0.6mm HSSW
A - ✔
B - self cure acrylic PMMA ; FABP (9mm)
List 6 signs of good wear and compliant patient on a URA on visit
- URA active component passive
- Signs of wear on URA ( acrylic part)
- patient can speak well with appliance
- no excess salivation
- patient can insert and remove URA easily
- teeth have moved (1mm per month)
- patient arrives wearing the URA
What are the dental advantages and disadvantages of fixed dental retainer
Advantages
* does not need compliance
* good aesthetics
* no occlusal interference
* does not affect speech
*Cheap and easy to make
Disadvantages
* Only retains anteriors
* Oral hygiene issue
* Tooth is prepped with etch
* composite can debond
* high failure rate ( 50% debond in first 6 months)
How infra-occluded teeth appear clinically?
- metallic sound on percussion
- found lower in the arch compared to adjacent teeth
- no physiological mobility
Name components of a fixed appliance?
- bracket/tube
- bands
- modules - help bracket and wire to connect
- Auxiliaries - depends on type of movement achieved
- anchorage components
- force generating components
What is frontal resorption?
- In frontal resorption, bone is removed from the surface directly adjacent to the force applied (remodelling of socket)
- whereas, in undermining resorption, remodelling occurs from surfaces further away from the applied force
What is an overbite?
- It is the extent of vertical overlap between the maxillary and mandibular incisors
- average 1/2 to 1/3
- can be average, increased or decreased
How is the molar relationship measured?
- Using the buccal segment of 6s relationship
- Class I - mesiobuccal cusp of upper molar occludes with mesiobuccal groove of lower 6
How is the canine relationship measured?
- using the buccal segment of the canines
- Upper canine occludes with embrasure between the lower canine and lower first premolar
