Collecting The Data Flashcards
Orthodontic Diagnosis
Consists of 4 important separate stages
Collect the data –describe the malocclusion
Create a problem list
Decide the treatment aims
Decide the treatment means
Aetiology of Malocclusion
Skeletal factors
Soft tissue factors
Dento-alveolar factors
Habits
How can we measure Skeletal Pattern?
3 aspects
1- Antero-posterior (Skeletal Class)
Kettle’s method or Zero Meridian line
2-Vertical
Facial thirds or Frankfort-Mandibular Planes Angle (FMPA)
3-Transverse
Facial fifths / observation of significant asymmetry
AP skeletal relationship –Skeletal Class 1 2 3
Class 1-The maxillary dental base lies2-3mm anterior to the mandibular dental base.
Class2- The maxillary dental base lies more than 2-3mm anterior to the mandibular dental base.
whentheteethareinocclusion.
Class3- The maxillary dental base lies less than 2-3mm anterior to the mandibular dental base.
Kettle’s Method of Assessing Skeletal Class?
Class 1 - horizontal wrist position =
contact with A and B point simultaneously
Class2- wrist drops towards the floor -
contact with A point before B point
Class3- wrist moves upwards - contact
with B point before A point
Why does Skeletal Class matter?
The bigger the skeletal discrepancy, the bigger the problem
The incisor relationship may not faithfully reflect the skeletal pattern because of:
Dento-alveolar compensation
Definition of Dento-alveolar Compensation
When the A/P jaw relationship is skeletal class2 or 3 but SOFT TISSUES (lips, tongue, and cheeks) tend to guide the erupting teeth into better position than skeletal relationship would suggest.
So mild class 2 or 3 skeletal relationship the incisor classification may still be class 1
Dento alveolar compensation in a patient with class 2 skeletal pattern.
Proclination of the lower incisors.
Dento alveolar compensation in pt with class 3
Proclination of upper incisors
Retroclination of lower incisors
To acheive Incisal contact
How do we diagnose vertical proportions?
- facial third / Average vertical facial proportion A=B or A slightly bigger
-Mandibular plane and fronkfort plane (FMPA).
Meet at occiput = average
Meet before occiput= increased
Don’t meet or after occiput = reduced
Why does increased lower face height matter?
1- May cause reduced overbite or anterior open bite (which need jaw surgery to correct)
2- The patient may not like look of long face
Why does reduced face height matter?
1- May cause deep overbite (hard to work to reduce)
2- Increased overbite traumatic bite.
Facial Asymmetry associated with?
Intra oral feature :
- centre -line discrepancies
- posterior cross bites +/- mandibular displacements
Define Mandibular displacement?
It’s the difference between the ICP and RCP, if it’s over 1mm.
Forward slide, could be right or left
What’s influence of soft tissue?
Teeth come to lie within neutral zone( zone of force equilibrium)
Why do lips matters in treatment?
- incompetent lip may result relapse of tx like corrected overjet increased
- same lower lip line- corrected overjet increased
- short upper lip -unattractive smile
- mouth breathing , cause gingivitis
- class 2. Div 1 , lip trap
Class 2 div 2, lower lip retroclines upper centrals and lateral are short in height so less influence
What tongue has effect on?
Habit- tongue thrust habit can cause anterior open bite AOB due to bimaxillary Proclination.
Digit habit cause?
Asymmetric open bite
Labial segment crowding from where?
Midpoint of canine forward.
Always start from front to back . And lower arch first
Crowding classification
Mild- less than 4mm
Moderate - 4mm-8mm
Severe - more than 8mm
Buccal segment crowding?
Midline of canine backwards
Canine angulation
Mesial angulated canine- tip of crown towards mesial
Distally angulated canine. - tip of crown distally
Incisor relationship
Class 1 - lower incisors occlude on cingulum plateau of the upper central incisor
CLASS 2- lower incisors occlude above cingulum plateau of the upper central incisors
Class 3- lower incisors occlude below cingulum plateau of the upper incisors
Overjet
Horizontal overlap of the incisors measured 2-4 mm average
