Dentofacial deformities Flashcards
What percent of individuals that have malocclusion are attributed to facial deformities?
2.7%
What direction is normal growth of the face?
-Downwaard and forward with lateral expansion
What two types of radiographs are essential when determining orthognathic surgery?
- Cephalometric
- Panoramic
T/F Any non-restorable teeth should be extracted before surgical intervention
True
The general rule is delay surgery until growth is complete in patients with problems of excess growth. What is a condition of excess growth?
-Mandibular prognathism
What is mandibular hypoplasia? When can you do surgery on these individuals?
- Growth deficiency
- earlier
What is the advantage of computer digitalized analysis?
-More accurate prediction of facial change
What are the disadvantages of computer digitalized analysis?
- Limited to two dimensional prediction
- Inability of computer to predict accurately every surgical change for every patient
- Adds cost
What was one of the earliest dentofacial deformities treated?
-Mandibular excess
How can you treat mandibular excess?
- Body ostectomy
- Anterior mandibular subapical osteotomy
- Vertical Ramus Osteotomy
What are three ways to do a vertical ramus osteotomy?
- Extra-oral approach
- Intra-oral approach
- Rigid fixation
What was the revolutionized way to treat mandibular deficiency?
-Bilateral sagittal split ramus osteotomy
Where does the cut go on a sagittal split osteotomy?
- Medial aspect via horizontal osteotomy
- Lateral aspect via vertical osteotomy
Besides the sagittal split osteotomy what other ways can you use to advance the mandible?
- Total subapical osteotomy
- Genioplasty (inferior border osteotomy
- Alloplastic chin implants
What three directions might excess maxillary growth occur?
- Anterior posterior
- Vertical
- Transverse
What are the facial characteristics with vertical maxillary excess?
- Elongation of face
- Narrow nose
- Excessive incisal and gingival exposure
- Lip incompetence
What type of bite is vertical maxillary excess frequently associated with?
-Anterior open bite caused by excess downward growth of MX that causes downward rotation of Md giving premature contact of posterior teeth
How do you correct a vertical maxillary excess?
- superior repositioning of maxilla in one or several pieces
- Le Fort I osteotomy with or without segmentalization
What are characteristics of maxillary and midface deficiency?
- Retruded upper lip
- Deficiency of paransal and infraorbital rim areas
- Inadequate tooth exposure while smiling
- Prominent chin
- Class III with reverse anterior
What is the treatment of a maxillary and midface deficiency?
-Le Fort I with or without bone grafting and segmentalization
What is the treatment of a maxillary horizontal deficiency?
-Le Fort I advancement
With orthognathic surgery how long are you in the hospital?
-1-4 days
What is the most common serious congenital anomoly affecting the orofacial region?
-Cleft lip and palate
When does cleft lip and palate occur?
-Between fifth and tenth weeks of fetal life
What is the risk of a parent having a child with a cleft?
1 in 700
If parents have a child with a cleft what is the odds that the next child will have a cleft?
- 2-5%
- this risk is the same for each succeeding child
If more than 1 person in immediate family has cleft what does the risk of cleft rise to?
10-12%
What is the objective of a cheilorhapy?
- Repair cleft lip
- Function and esthetics
- Restore orbicularis oris muscle
What is the objective of a palatorhaphy?
- Repair cleft palate
- Create mechanism capable of speech and deglutition without interfering significantly with maxillary growth
what are 4 periodontal considerations when evaluating a patient for dentofacial surgery?
- OHI
- perio charting
- scaling and root planing
- evaluation of attached keratinized tissue
when malocclusion involves skeletal discrepancy, treating with orthodontics alone may result in adequate ___ but poor ___ or ___
- occlusion
- poor facial or dental esthetics
- poor long-term prognosis for post-treatment retention
presurgical orthodontics often takes how long before the patient is ready for dentofacial surgery?
12-18 months
what were the early surgical corrections for mandibular deficiency, and what was the issue?
- early correction included an extraoral approach, vertical ramus osteotomy, and iliac bone grafting
- resulted in high relapse
describe how correction of mandibular deficiency was revolutionized in the 70s
- bilateral sagittal split ramus osteotomy (BSSO)
- significant bone overlap for post-op stability, reducing relapse
- use of rigid fixation with screw and plates
- no need for IMF usually
which surgical approach for mandibular deficiency can increase lower facial heigh with simultaneous bone grafting, and is rarely used?
total subapical osteotomy
what type of mandibular deficiency is the total subapical osteotomy procedure typically used?
class 2 dental relationship but the anterior-posterior position is ok (chin)
which surgical approach for mandibular deficiency is used with or without other osteotomies, is considered “cosmetic” by insurance, and can also correct asymmetries?
genioplasty (inferior border osteotomy)
3D computerized surgical planning combines what 3 things to produce computerized models of skeletal and occlusal abnormalities?
- laser
- optical
- CT scans
3D computerized surgical planning improves the understanding of what 3 things?
- bone movements required at surgery
- potential difficulty with bone interferences
- possible need for bone grafting
orthognathic surgery is typically performed in what setting?
hospital setting, in an operating room
what are the components of perioperative and postoperative care for patients receiving orthognathic surgery?
- antibiotics, steroids, and close observation
- pain medication as needed
- nasal airway as needed for maxillary surgeries
- liquid to soft diet
- oral hygiene
cleft lip and cleft palate is less frequent in what population? more frequent?
- less frequent in african americans
- more frequent in asians
what gender is cleft lip and palate more common in?
-boys more than girls with a ratio of 3:2
clefts typically can affect what 3 anatomical structures?
- lip
- alveolar ridge
- hard and soft palates
what fraction of clefts are unilateral (what side is more common)? bilateral?
- 3/4 are unilateral (left > right)
- 1/4 are bilateral
the causes of clefts are unknown, but may be related to what factors?
- genetic predisposition
- environmental factors, like nutrition, radiation, drugs, hypoxia, viruses, and vitamin excesses or deficiencies
a parent who has a cleft has a ___% chance that their child will have a cleft
2-5%
unaffected siblings of a child with a cleft have ___% chance of their child having a cleft
1%
if a syndrome is involved in clefting, the risk for recurrence within the family can be as high as ___%
50%
what are the dental problems with clefts?
- alveolar cleft
- malformed or missing teeth
- displaced teeth
- supernumerary teeth
what are the malocclusion problems with clefts?
- class III (pseudo-prognathism)
- collapse of lesser segments
- need for orthodontics and/or orthognathic surgery care
what are the nasal deformity problems with clefts?
- alar flare on the cleft side
- columella pulled to non-cleft side
- lack of bony support at the nasal base
in surgical corrections of clefts, what should be the last surgery performed?
nasal correction
what are the feeding problems with clefting?
- can’t feed normally
- can’t generate negative pressure
- use specially designed nipples, eye droppers, or large syringes
what are the ear problems associated with clefting?
- levator veli and tensor veli palatini muscles can be unattached
- make the middle ear a closed space
- requires myringotomy
- leads to hearing loss
what are the speech difficulties associated with celfting?
- retardation of consonant sounds
- hyper-nasality
- persists after surgical correction
- need speech therapy
what is the rule of 10 for surgical repair of cleft lips?
- 10 lbs
- 10 weeks old
- 10 g/dL hemoglobin
- should be treated as early as possible under these conditions
when should the treatment of cleft palate be performed?
- usually 8-18 months
- sometimes wait until 4-5 years old
what are the advantages of early surgery for the surgical repair of cleft lip and palate?
- facilitate palatal and pharyngeal muscle development
- ease of feeding
- development of phonation skills
- better auditory function
- better hygiene
- psychologic
what are the disadvantages of early surgery for the surgical correction of cleft lip and palate?
- more difficult on small structures
- scar formation causes maxillary growth restriction
what are the esthetic considerations of cheilorrhapy?
-normal appearance of vermillion, cupids bow, and philtrum
T or F:
surgical techniques for palatorrhaphy and cheiloplasty vary widely with the surgeon and patient
true
T or F:
palatorrhaphy surgery that corrects a palatal cleft involves fusing the separated bone fragments together
false
-it is closed with soft tissues only
how is a palatorrhaphy performed?
- soft tissues are incised along the cleft margin and dissected from the palatal shelves
- lateral releasing incisions are used to obtain a tension-free closure
palatalorrhaphy is closed in what 3 layers?
- nasal mucosa
- muscle
- oral mucosa
