Concepts of Growth and Dev. Pt 2 Flashcards
what is the most common reason to remove mand. 3rd molars?
To prevent incisor crowding
In class we covered 2 studies regarding 3rd molars as the cause of mandibular incisor arch crowding. What did each conclude?
1-the removal of third molars to reduce or prevent late incisor crowding cannot be justified
2- there was not enough evidence to incriminate third molars as being the only or even a major etiologic factor in the late lower dental arch crowding
One theory is that crowding develops as the mandibular incisors, and perhaps the entire mandibular dentition moves in what direction?
distally relative to the body of the mandible.
what other factors may be responsible for mandibular crowding?
1-posterior wear
2- stress, clenching, grinding
3-changes in muscular forces
**ultimately the cause is unknown
based on a study, who is more likely to recommend prophylactic removal of 3rd molars, surgeons or orthodontists?
Surgeons
*orthos are increasingly under the thought that 3rd molars do not cause incisal crowding
what is intrauterine molding?
distortions on the face or body due to pressure against the baby while in utero.
*baby’s arm pressed against his face can result in a facial depression because there is a decrease in amniotic fluid to that area
Pierre Robin Sequnce
-small jaw
tongue falls back in throat
difficulty breathing
-cleft palate
-acid reflux
-sox 9 gene
-AD
-Repeated ear infections
-Teeththat appearwhen the baby is born (natal teeth)
- congestive heart failure
-hypertensionPierre robin sequence TX
- break the jaw and use a device to move the jaw forward
- lip-tongue adhesion to tether tongue anteriorly
*fix cleft palate, may beed tracheotomy, tympanostomy tubes, monitor
what evidence is there that the mandibular condyle is not a growth center?
if the lateral pterygoid muscle rips the head of the condyle off, there is no growth impairment
if the condyle breaks off and resorbs what happens?
80% chance it will regenerate from the periosteum
5 late causes of TMJ injuries
1-Facial asymmetry,
2-Malocclusion,
3-Growth disturbance, 4- Osteoarthritis,
5- ankylosis (fusion across the joint so that motion is impaired
if TMJ trauma occurs, the px can experience what 5 things?
1-Limited opening and excursive movements
2-Deviation of opening
3-Malocclusion manifesting in cross-bites
4-Short ramus height
5-Hyper-eruption of the teeth on the opposite side, infra-eruption on the ankylosised side
what is the most common cause of facial asymmetry in regards to the condyle?
trauma–the condyle may fail to grow vertically
Cleft lip results from failure of what to fuse?
maxillary swelling to fuse with the intermaxillary process
*can be unilateral or bilateral
cleft palate results from what failing to fuse?
two palatine shelves
In patients with bilateral cleft lip, the _________ is situated too far forward beyond the tip of the nasal septum
primary palate
cleft lip may be caused by what 3 drugs?
1-phenytoin
2- vitamin A
3-Methotrexate
what 4 drugs can cause cleft palate
1- phenytoin
2- Vit. A
3- corticosteroids
4-cigarette smoke
How common is cleft lip
1 or 2 out of 1000
clefts are more common in ?
Asian, Latino, or Native American descent
what state has highest cleft incidence?
Utah at 2.2/1000
babies born with a cleft lip or palate will have trouble eating. what do you do?
make a good seal in oral cavity, make sure baby doesn’t choke, use obturator
