Class III Flashcards
Describe a suitable pt for camouflage tx to fix a class III malocclusion
- Mild-Moderate Skeletal III pattern
- Px happy with facial profile
- Potential to procline upper teeth & retrocline lowers
- Good overbite
Clinically (in regards to teeth only) what may you expect to see in a class III malocclusion pt?
- Reduced incisor show at smiling
- Increase buccal corridor dark space
- Upper dentition tends to have more crowding
- Incisors will have compensation for the Skeletal base, i.e. Proclined maxillary and retroclined mandibular incisors
- Potential posterior crossbite
When are fixed applainces needed when a pt needs orthgnathic surgery?
Fixed appliances required
Before surgery
During surgery
After surgery
What is considered late age treatment when treating class III malocclusion? And what tx can be done at this stage?
Over 16 years - NON-GROWING
Growth modification NO LONGER AN OPTION
Camouflage if possible (facial profile not a concern) or Orthognathic Surgery + Fixed appliance
What teeth are normally extracted for camouflage tx of class III malocclusion?
Fixed appliances usually with the extraction of lower 4s or upper 5s
What are the components of an upper removable appliance?
Remember ARAB
A - active
Z-spring or T-Spring or Screw (more than one tooth)
R- retention
Adam’s Clasps 6s and Ball ended Clasps on Es
A- anchorage
The resistance to unwanted tooth movement
Involvement of more teeth in the appliance than just the anterior teeth
B- baseplate
Posterior bite blocks and midline screw - allows for the bite to be opened and expansion of the upper arch
What are some relavant history questions you would ask a pt with class III malocclusion?
- Px concerns? Facial or dental concerns
- Age: Growing (10-16 years) or non-growing, to determine functional appliance use
- Family history: Genetic skeletal III (does anyone in the family have similar concerns? Has anyone ever had facial surgery?)
- Medical History
- Previous orthodontic work?
- Habits
Why is it important to diagnose potential mandibular prognathism in skeletal class III pts at the start of the treatment?
(increased growth of mandible)
Skeletal III patterns with mandibular prognathism can commonly have an asymmetry, it is important to diagnose this at the start of any treatment as its management will need to be planned accordingly
Label the following features that are common to see in a pt with a class III malocclusion
- Increase scleral show (white part of eye)
- Cheekbone flattening
- Paranasal hallowing (either side of nose flattened)
- Obtuse Nasio-Labial Angle
- Thin upper lip
- Prominent chin
- Increased throat length
What special investigations would you need to diagnose a class III malocclusion?
OPG
Lateral Ceph
+/- Upper standard occlusal
Define a skeletal III relationship
Forward mandibular position with respect to the cranial base or maxilla
What are the treatment options for class III malocclusion?
- No treatment
- Growth modification
- Camouflage
- Orthgnathic surgery
Why do we treat class III malocclusion?
- Concerns regarding aesthetics
- Psychological well being
- Masticatory problems
- Speech problems
- Concerns regarding dental health - (tooth surface loss, gingival recession)
Define class III molar relationship
The mesiobuccal cusp of the maxillary first molar occludes posterior to the buccal groove of the mandibular first molar
What is considered early treatment when treating class III malocclusion? And what tx can be done at this stage?
Less than 10 years as still growing and has mixed dentition
Growth Modification
(however poor stability, compliance and unpredicatble growth)
Define Class III incisor relatoinship
The lower incisor edge lies anterior to the cingulum plateaux of the upper incisor teeth; overjet may be reduced or reversed
BSI Classifictaion
What are some skeletal aetiological factors that contribute to a class III malocclusion?
Short or Retrusive Maxilla (Hypoplasia)
Long or Prognathic Mandible (Hyperplasia)
Most pts have a combinatiom of both
