lecture 5

Question 1

failure to fully erupt within the expected developmental time period

Answer 1

impacted tooth

Question 2

tooth not having perforated the oral mucosa

Answer 2

unerupted tooth

not all unerupted teeth are impacted

Question 3

time period for 3rd molars:

~crown formation
~root formation apprx. 50%
~average formation
~position does not change substantially after _ years

Answer 3

crown formation - 14 years

50% of root - by age 16

average formation 20-24

position doesn’t change after 25

Question 4

theories behind impacted 3rds

Answer 4

differential root growth between mesial and distal

inadequate arch space*

dental development lags skeletal development

obstruction secondary to cyst, tumor, supernumerary teeth

Question 5

_ classification based on inclination of impacted tooth to long axis of 2nd molar

Answer 5

winter’s classification - based of images/radiographs

also have ADA coding - soft tissue, partial bony, full bony

Question 6

winter’s classification mandibular 3rds

_ - 43% generally easiest

_-6% most difficult - have to remove quite a bit of bone to get it out

_3%- difficult but not as hard

_-38% generally easy - little bit of bone removal

what about maxillary?

Answer 6

mesioangular

2. distoangular - most difficult
3. horizontal
4. vertical - generally easy

maxillary:

1. vertical 63%
2. distoangular 25%
3. mesioangular 12%
4. horizontal - rarely seen less than 1%

Question 7

indications for 3rd molar removal
_-to tx a currently active process/disease

_-to prevent future disease or other problems

Answer 7

therapeutic - to treat a currently active process

prophylactic - to prevent future disease, because the dentist says
Academic and science think it’s a good idea if asymmpotomatic

Question 8

what are some therapeutic reasons to remove 3rds

Answer 8

pericoronitis
caries
pathological resorption
pathology
eruption pain
crowding
post-ortho
orthognathic surgery
in the line of a mandbile fracture
periodontal disease
lack of attached gingiva
crowding

Question 9

what to do with active pericoronitis (operculum)

Answer 9

bacteria and infection can get down there

Try not to take out active acute pericornoitis
Want to make sure we have infection undercontrol before extraction

Question 10

if having orthognathic surgery we like to get the 3rd out _ months before the surgery

Answer 10

9 months

Question 11

ideal patient for 3rd molar extraction

Answer 11

2/3 root formation

18-25 years old, healthy

no psychological contraindications
no job restrictions to numb lip

Question 12

age being contraindictions to removal of 3rds

Answer 12

young age - mandible may grow to accommodate

old age - most common contraindications for removal - 40 years

Question 13

why is older than 40 a contraindication for 3rd molar extractions

Answer 13

highly calcified bone
less flexible bone
recuperate more slowly
increaased tendency toward mandibular fracture, non-resolving parasthesisa, infection(osteomyelitis)

if tooth has been retained withou sequellae, it may be less likely for problems to develop

monitor with pan xray every 1-2 years

surgical intervention for clinical symptoms or radiographic signs

Question 14

most common impacted teeth?

Answer 14

Mn 3rd> Mx 3rds > Mx canine> Mn PM > Mn Canine > Mx PM > Mx CI > Mc LI > Mn 2nd molar

Question 15

why are max canines the 3rd most impacted tooth

technique for exposure? incision usually _

Answer 15

due to crowding from adjacent teeth and difficult route to erupt

incision usually sulcular

open vs closed