Ortho Flashcards
How do you examine a person’s growth stage?
Using their C2-4 vertabrae
What is the best timing for class II treatment?
Class II is best treated with inclusion of peak mandibular growth which is the end of CS2 and the begining of CS3
What is the best timing for class III treatment?
Class III is best treated with maxillary expansion and protration and is only effective before peak growth which is during CS1 and CS2
In considering growth and development, an understanding of the concepts of pattern, variability and timing is important. What is your understanding of each of these terms?
Predictability - is the common incidence of an event
Variability - a spectrum of an incidence
Timing - same events may happen at different times
What is a malocclusion?
Malocclusion is a failure of the dento-alveolar compensatory mechanism. Tooth position post-eruption is influences by ST and oro-facial function (habits)
What are the reasons for crowding?
Primary crowding - result of smaller jaws
Secondary - result of early exfoliation of the deciduous tooth thus permanent erupts in a different postion
What is the length of a dental arch?
Antero-posterior distance from CI to the most distal point of the 2nd primary molars
What is the arch circumference?
Distance measured aroudn the arch from the mesial contact of the 1st permanent molars to the contralateral mesial contact of the 1st permanent molar
What is inter-canine width?
Horizontal distance between the cusp tips of the upper canines or the lower canines
How do permenent incisors fit into the arch?
Increased space requirments gained from:
- Residual spacing between deciduous incisors
- Permanent incisors erupt lingual originally and move more labially
- Deciduous canine move distally as insisors erupt
- Transverse increase in the intercanine arch width
Usually, distema between central incisors close but when do they persisst?
- Decidou canine has been lost
- Upper incisors are proclined
- High frenum attachment
To fix:
1. Wait for canine to erupt
2. Attempt ortho
3. Frenectomy might be needed
How do you determine skeletal class according to AP skeletal classification?
You need to draw the line between ST glabella - Subnasale - ST Pogonian
Class I: Mx 2-4 mm anterior to the mandible
Class II: Md retrusive to Mx - ST Pogonian is posterior tot he line
Class III: Md protrusive relative to Mx ST pogonian anterior tot eh vertical line
What are the angle molar classes?
Always need the first permanent molars for this .
Class I - Mesio-buccal cusp of the upper molar coincdes with the buccal groove of the lower molar
Class II - Is anterior to the buccal grove and can be shifted forward by 1/4, 1/2, 3/4 or full unit (full unit = size of a premolar)
Class III - Is posterior to the buccal groove and can be shifted backward by 1/4, 1/2, 3/4 or full unit (full unit = size of a premolar)
What is the definition of the Class I incisor relationship?
It is a relationship of the mx and md incisors which represents a truer reflection of the underlying skeletal base relationship and what is often of most concern to the pt.
Class I is when lower central edges occlude with or lie immediately below the cingulum plateau of the upper central
What is the definition of the Class II incisor relationship?
It is a relationship of the mx and md incisors which represents a truer reflection of the underlying skeletal base relationship and what is often of most concern to the pt.
Class 2 Lower central edges occlude posterior to the cingulum plateau of the upper central
Div 1 - increase OJ is observed due to upper central incisor proclination
Div 2 - Increase or minimal OJ and upper central incisor is retroclined
What is the definition of the Class III incisor relationship?
It is a relationship of the mx and md incisors which represents a truer reflection of the underlying skeletal base relationship and what is often of most concern to the pt.
Lower central edges occlude anterior to the cingulum plateau of the upper central incisor. OJ is reduced or edge to edge.
What is tipping?
Apex is in normal position but crown is incorrectly positioned
What is displaced teeth?
Both apex and crown are incorrectly positioned
What is rotated teeth?
It is when teeth are rotated along the long axis
What is infraocclusion?
Tooth has not reached the oclcusal plane due to trauma
What is supraocclusion?
Tooth has erupte past the occlusal plane
What is a transposed teeth?
When 2 teeth are in reversed position
What is the hierarchy of MOCDO?
DO NOT SPELL MOCDO OR PUT AS DOT POINTS.
Missing teeth
Overjet
Crossbite
Displacement of contacts points (crowding, spacing and rotation)
Overbite (decrease, average, increase complete or incomplete to the tooth or soft tissue or traumatic to soft tissue)
Why are forward and backward rotations are such big deal?
Rotation of the mandible is normal, however when rotation is significant, there is imbalance in the growth of the anterior facial height and posterior facial height.
What are some of the features to look out for in backward rotators?
- increased anterior facial height
- Long face
- Class 2 skeletal relationship
- reduced overbite
What are some of the features to look out for in forward rotators?
- Increased OB
- Lower incisors crowding with age
- Slow space closure
How do you write a referral letter in ortho?
- Date of referral
- Referring practiotioner detailes (name, address and phone number)
- Referring practitioner qualifications
- Department from which pt is being referred from
- Name of recipient
- Clinic adress
- Contact
- Dear Orthodontist, My patient….
- Name of patient, their age, sex, quick medical history, “presented to my clinic with a “CC””.
- They are presenting with average facial proportions, mixed/permanent dentition class xx incisal relationship on class xx skeletal base complicated by:
- MOCDO BUT DO NOT PUT MOCDO
- Their IOTN is xx because of xx
- Quick summary of medical history, social history
- Dental history including caries risk,motivation for dental treatment, previous treatments, oral hygien status and habits.
- What has been done so far
Please consult and consider definitive orthodontic treatment for space closure, as well as for the impacted canine
Thank you for your time,
I look forward to hearing from you
Your faithfully
Name
Qualification (eg BDS4 student)
How to write the diagnosis for an ortho case?
Start always with their name, age, sex, quick MHx and CC (both parent and patient)
- Patient presents with
- Mix/deciduous or permanent dentition
- Incisal relationship
- On which skeletal class
- Vertical proportions
- E/O findings
- Complicated with:
- Missing teeth
- Overjet
- Crossbites
- Displaced contacts (crowding, spacing or rotations)
- Overbite (decreased, average, incrreased and complete/incomplete to the soft tissue or tooth with/without soft tissue trauma
- Rotation of the mandible
- IOTN and why
- Oral hygiene (good or poor)
What are the complications of orthodontic treatment?
- Pain and increase mobility
- Difficulty speaking and eating
- Effect pulpal status
- Root resorption
- Loss of alveolar bone
- Enamel demin
- Failed tmt
- Decrease severity of malocclusion
What is the influence of non-nutroive sucking on malocclusion?
- Posterior cross-bites due to increased cheek pressure
- Anterior open bites non symetrical
- Increased overjet
What are some of the way we can treat non-nutritive sucking behaviour?
Primary intervention: cessation
Secondary: determine the effectivness of all of the interventions
Some of the interventions:
- Removal of comforting object
- Fitting an ortho appliance to interfere with the habit
- Application of aversive taste to digit sucking
- Psychological interventions
What is infra-position?
IIt is an eruption issue
What are the causes for unerupted maxillary incisors?
- Early extraction or loss primary teeth with or without space loss
- Prolonged retention of primary teeth
- Crowding in the upper labial segment
- Previous trauma - dilaceration of the permanent teeth
What is aetiology of missing teeth?
Skeletal - x
Dental - congenital missing; systemic conditions; early loss due to caries/trauma/root resorption from impacted tooth
Soft tissue - x
Habit - x
What is aetiology of delayed eruption?
Skeletal - x
Dental - systemic conditions; impaction/supernumerary tooth/dilaceration/arrested tooth development from traum/ectopic tooth germ position; crowding; prologned retention of deciduous teeth; cyst/tumor; amelogenesis imperfecta; nutritional deficiencies
Soft tissue - x
Habit - x
What is aetiology of supernumerary teeth?
Skeletal - x
Dental - congenital
Soft tissue - x
Habit - x
What is the aetiology of increase overjet?
Skeletal - retrognathic mandible or prognathic maxilla or both
Dental - proclined tooth
Soft tissue - lip trap;
Habit - tongue thrusting; thumb sucking
What is the aetiology of reversed overjet?
Skeletal - retrognathic maxillar or prognathic mandible or both
Dental - retroclined tooth
Soft tissue - x
Habit - x
What is the aetiology of crossbite?
Skeletal - maxillary constriction from habits
Dental - (only when 1 tooth involved) ectopic eruption, crowding
Soft tissue - x
Habit - maxillary constriction from mouth breathing, thumb sucking
What is the aetiology of displacement of contact points?
Skeletal - discrepance between dental and arch size
Dental - early loss of deciduous teeth and subsequent space closure
What is the aetiology of increased overbite?
Skeletal - mandibular forward groth rotation: increased posterior facial ehight
Dental - posterior tooth wear, infraocclusion of posterior teeth
Soft tissue - abnormal tongue posture causing infraocclusion of posterior teeth
Habit - thumb sucking, lateral tongue thrust causing infraocclusion
What is the aetiology of reduced overbite?
Skeletal - mandibular backward growth rotation; reduced posterior facial height
Dental - x
Soft tissue - x
Habit - x
How do you calculate a patient’s skeletal relationship on lat ceph?
Take the SNA plane angle - SNB plane angle.
If the angle difference is between 2-4 degress = class I retionship
If angle difference is above 4 degree = class II skeletal relatioship
If angle difference is below 2 degrees = class III relationship
What is MMPA and how do you construct and calculate it?
Maxillary-mandibular plane angle is a ratio between the posterior and anterior facial heights.
Joins ANS and PNS for maxilla
Joins Me and Go
If it is 23-31 degrees - patient has a normal angle
If above 31 degrees patient has a high angle
If below 23 degrees patient has a low angle
How do you calculate facial proportions?
Draw maxillary plain
- Connect N to the maxillary plain - measure it
- Connect Me to maxillary plain - measure it
For lower facial height
% = Me to maxillary plain / (Me to maxillary plain) + ( N to maxillary plain)
If the lower facial height is:
53-57% patient has average vertical proportions
above 57% patient has increased vertical proportions
below 53% patient has decrease vertical propotions
What are the cause for increased MMPA?
1, Increase in lower anterior face height
- Reduced posterior face height
- Combination of both
What are the causes for reduced MMPA?
- Reduced lower anterior face height
- Increased posterior face height
- Combination of both
