Orthognathic Surgery Flashcards
What is thalassemia?
Produce a large amount of abnormal RBC’s everywhere. Effects maxillary more because it has sites of extra-medullary hematopoiesis where mandibular does not
What is the etiology of jaw deformities?
- Congenital
- cleft
- craniofacial - Developmental
- growth imbalance - Acquired
- traumatic
- pathologic infectious
What is glossoptosis? What is micrognathia?
Glossoptosis is downward displacement or retraction of the tongue which may cause no fusion of hard palate –> cleft palate
Micrognathia is an undersized/small jaw
What is condylar hypoplasia?
It is when the condyle ramus does not grow
- the posterior maxilla does not descend
- steep occlusal plane
- clockwise facial rotation
- bilateral micrognathia (bird face)
- unilateral hyperplasia
- depends on condylar growth factor
What is mandibular excess (condylar hyperplasia)?
- could be from tumor
- hemimandibular hyperplasia (3-D enlargement of the mandible, terminates at the symphysis, canted maxilla, presents before puberty, anterior teeth tilted to affected side)
- hemimandibular elongation
- mandible descends/maxilla follows
- bilateral/unilateral
What are the 5 questions/factors when diagnosing a dentofacial patient?
- Skeletal base
- Dental occlusion
- Soft tissue drop
- Functional problems
- Patient goals
How do you survey the facial skeleton?
- XYZ planes
- Facial exam
- Lateral and P.A cephalogram
- Natural head position
- Articulated facebow mounted studies
- Worms eye view
- Symmetry range
When you do a lateral assessment, what do you evaluate/observe?
Your observations are relative to the bell line
- upper lip/lower lip/chin
- facial thirds
- infraorbital paranasal evaluation
- nasolabial angle/labial mental
- mandibular plane angle
- mental cervical angle
What should you see in a balanced orthognathic position?
Upper lip is most predominant, lower lip behind it, then chin behind the lower lip
What is dental occlusion, dental compensation? Why is this important?
Dental compensation occurs as skeleton grows. It is where the dental occlusion compensates for the skeletal deformity.
This is important because before we can do surgery, we must decompensate the dental compensation (need dental discrepancy to reflect skeletal discrepancy.
Ex. Lower jaw grows forward –> less influence of tongue and lower lip increases –> lower teeth tip back (lingual inclination of incisors)
What is a normal occlusion?
The mesiobuccal cusp of the maxillary first molar is aligned with the Buccal groove of the mandibular first molar.
What is class I malocclusion?
It is where a normal molar relationship exist is but there is misalignment/crowding/cross bites/ or too much space
What is class II malocclusion?
It is a malocclusion where the molar relationship shows the Buccal groove of the mandibular first molar is distally positioned to the MB cusp of the maxillary first molar, thus the anterior maxillary teeth are forward – overbite
What is a class III malocclusion?
The lower molars are far forward and do not fit into their corresponding upper molars. The Buccal groove of the mandibular first molar is mesial lay positioned to the MB cusp of maxillary first molar. Underbite
What do you see in a class II malocclusion for dental compensation?
Since there is overbite, we could see facially inclined mandibular incisors for dental compensation. Must decompensate before treatment of other possible problems such as small airway
What do you see in a class III malocclusion for dental compensation?
Lower jaw too forward so the lower teeth are inclined lingually for dental compensation
What is skeletal apertognathia?
It is skeletal open bite – often associated with airway problems, open mouth breathing
Why are we concerned about the soft tissue drape over hard tissue?
- are the lips competent?
- is there peri oral straining? - mentalis, obicularis oris
- upper lip/lower lip/chin relationship
What is the purpose of orthognathic surgery?
It is to reposition one or both jaws to correct irregularities, but orthodontics is also required to make sure the etch are in correct position after surgery.
Goals:
- improve ability to speak, chew, breath, and appearance
What are some functional problems that could occur due to deformity?
- Poor dental health
- periodontal considerations
- occlusal attrition
- balancing occlusal forces
- dental trauma
- long term prosthetic considerations - Airway issues
- Mastication
- Pain
- Speech
- Self image
- Soft tissue injury
- Whole life impairment
Name some examples of functional health problems that arise in the category of dental health
- Open bites produce dental breakdown
- Retrognathic patient will often manifest periodontal problems
- Class III is associated with Incisal wear
Name some examples of functional problems that arise in the category of mastication
- Normal diet?
- Incise food
- Create and swallow a food bonus
- Dietary assessment
- Pain or difficulty chewing
What sorts of airway problems might a patient have from gnathic problems?
- Obstructive sleep apnea
- Snoring
- Nasal airflow
- Mouth breathing
- Exercise intolerance
*diminished airway can lead to decreased muscle tone
How is speech effected by these orthognathic problems?
- articulation (S and T sounds, lisping)
- phonation (hypo and/or hyper nasality)
- rapid conversational speech
- resonance, voice quality
