White Paper - 3rd molars

Question 1

what factors do we look at to more accuratley predict or answer the question - can the course of an unerupted third molar be predicted?

Answer 1

1. tooth angulation
2. degree of root development
3. depth relative to the occlusal plane
4. size of tooth
5. available space for eruption

Question 2

when say ‘ available space for eruption’ what are we more closely looking at?

Answer 2

generally described as the mandibular ramus (xi point) and the distal of the second molar

Question 3

one thing that is def. necessary for 3rd molar to errupt

Answer 3

SPACE - needs to be adequate space between the anterior border of the mandible and the distal of the mandibular second molar – to then allow a successful eruption to the occlusal plane

*eruption to the occlusal plane does not imply a good state of health, particularly with respect to soft tissue support

Question 4

T/F - position of 3rd molar can change in position into the 3rd decade?

Answer 4

true - unerupted teeth can change position past 25 yo and into the 3rd decade of life.

Question 5

resorption of the distal of the second molar is more associated with what type of impacted third molar angulation?

Answer 5

mesioangular and horizontal impactions

Question 6

from a periodontal perspective - how does the presence of an impacted third molar impact?

Answer 6

presence of a third molar adversely affects the periodontium of adjacent 2nd molars in
- DISRUPTION OF PDL
- ROOT RESORPTION
- AND POCKET DEPTH ASSOCIATED WITH LOSS OF ATTACHMENT

Question 7

disto-angular
mesio- angular
horizontal

where are roots and crown in relation to the second molar crown

Answer 7

disto-angular - the roots are closer to second molar with the crown tilted back

mesio angular – roots are tilted back and crown is closer to second molar

horizontal - roots are closer back and crown is closer to the crown of second molar

Question 8

T/F when a visible third molar is present - there is a greater chance of periodontal findings / pocket depth

Answer 8

true – white paper quotes
- greater probability of probing pocket depth greater or equal to 5 mm on distal of second molar when a visible 3rd molar is present

*in similar clinical scenario –> pocket depth of over 5mm has shown to be assoc. with loss of attachment

Question 9

does the removal of impacted third molar negatively impact the periodontium of the adjacent second molar?
- obviously not a strict answer –> describe

Answer 9

it CAN.
pre-operative environment is important to consider
1. was there an intra-bony defect prior to removal?
- what is the size of the second / third molar contact area
2. what is the age of the patient –> research has shown that earlier removal (20 years vs over 30 years) – older adults more likely to have adverse outcomes
3. level of plaque control that is present –> does the patient have good / bad home care, etc.

*imp to recognize there are studies that show little to no deleterious effects vs some that do show and these aspects are ones that are imp to know.

Question 10

a way to mitigate a reduction in post-op loss of PDL attachment?
ex) surgical approach? guided tissue regen? using DBP? - demineralized bone powder?

Answer 10

NO one surgical approach in the removal of 3rd molars that will minimize loss of PDL attachment was identified

GTR / DBP MAY be beneficial in instances where there is evidence of significant PRE EXISTING attachment loss

scaling and root planning, and plaque control have the potential to reduce post-op loss of attachment

Question 11

advantages seen in using DBP in thirds extractions?

Answer 11

does not seem to offer too much of an advantage other than….!!!!
- those who are HIGH risk going into the procedure –> older than 26, pre-existing attachment loss (over 3mm) and having mesio-angular or horizontal impaction

*scaling and RP in addition to plaque control measures at time of ext could have influenced no significant benefits seen with using GTR.

Question 12

presence of a third molar negatively impact the progression and/ or severity of periodontitis in adjacent teeth?
there are FOUR type of info that could help support this and they are…

Answer 12

1. an association of third molars with greater periodontal disease severity
2. an association between the presence of 3rd molars and progressive loss of attachment on NON- third molars (w/ more emphasis on second molars)
3. the influence of 3rd molars on the periodontal micro-flora, esp the putative pathogens, and on the molecular markers of inflammation
4. and what the effect of removing the 3rd molar is on factors 2 and 3 above

Question 13

major perio disease severity aspect to note

Answer 13

patients with VISIBLE third are more likely to have INCREASED SEVERITY of perio whether mild, moderate, severe (just greater overall)
- based on pocket depth ad BOP

Question 14

is perio progressive in adjacent teeth with visible 3rd molars?

Answer 14

in presence of visible 3rd molars, periodontitis involving adjacent teeth is progressive and only partially responsive to therapy.

Question 15

when evaluating a visible 3rd molar - what should the assessment include?

Answer 15

assess the perio associated with 3rd molar AND the second molar
- include the anatomical AND MECHANICAL LIMITTIONS TO REOMVAL OF PLAQUE
- presence of pocket depth 4-5 mm or above and/or bleeding on probing should be recognized as possible predictors of future progression of periodontitis

Question 16

The association of overall increased disease severity in the presence of visible third molars, the progressive nature of periodontitis involving non-third molars when third molars are present, the relationship between visible third molars and bacteria associated with severe and refractory periodontitis, and the negative impact of visible third molars on treatment outcomes all lend support to the hypothesis that third molars should be considered as a possible predictor of periodontitis.

Answer 16

take it out if visible with pockets essentially

Question 17

basic definition of pericoronitis and tx?

Answer 17

pericoronitis –> an acute infection of enveloping mucosa and gingiva associated with eruption of third molars , clinical symptoms include pain, swelling, erythema, and purulence

majority of cases the flora of anaerobic bacteria predominate

TX–> antibiotic therapy coupled with surgical intervention (surgical removal of the tooth associated with the infection is curative)

***ABSENCE OF CLINICAL SYMPTOMS DOES NOT INDICATE ABSENCE OF DISEASE OR PATHOLOGY.

Question 18

data on microflora and asymptomatic disease in the thrird molar region show what 5 things

Answer 18

1. absence of symptoms does NOT indicate absence of disease
2. pathogenic bacteria (red and orange complexes) in clinically sig. numbers exist in and around asymptomatic 3rd molars
3. perio disease as indicated by probing depths over 4 mm exist in and around asymptomatic third molars
4. indicators of chronic inflammation exist in perio pockets in and around asymptomatic third molars
5. perio disease progresses in the absence of symptoms

Question 19

postoperative risks of pocketing and age association?

Answer 19

**ALL risks associated with third molar removal increases with increasing age
papers define over 25 years

in addition to things like fractures, sinus involvments, etc

Question 20

germectomy? aka

Answer 20

lateral trepanation –> germectomy is defined as the removal of a tooth that has one third or less of root formation and also has a radiographically discernible periodontal ligaments

Question 21

role of germectomy and impact on post op complications like nerve incolvement , osteotits, or perio

Answer 21

It does appear that early third molar removal mayt be associated with a lower incidence of morbidity and also less economic hardhship from time off

Question 22

orthodontic and prosthodontic considerations in removal of third molars

Answer 22

most studies focus on the crowding associated with lower mandibular incisors –> but little attention has been paid to changes in arch width, form or length

**ETIOLOGY OF DENTAL CROWDING IS COMPLEX AND MULTIFACTORIAL
some studies show evidence for both for and against thirds contributing to crowding –> most accept play some sort of role in crowding — but role may not be clinically significant

no cause and effect relationship / study has been performed and therefor determined

Question 23

should asymptomatic 3rds under an existing or planned removable prosthesis be removed?

Answer 23

Many clinicians recommend removal of impacted third molars under planned or existing removable prosthesis (full or partial dentures) - limited data

this topic is dynamic and unpredictable – management of these teeth are best determined from multifactorial approach - like age of patient, position of tooth, anticipated difficulty of removal, type of overlying prosthesis and risks associated with removal

Question 24

is a CT scan associated with a decreased incidence of IAN nerve involvement?

Answer 24

CT permits localization of the IAN canal in the superior-inferior and medio-lateral positions; detection of an intra-radicular path; determination of the distance between the tooth and IAN canal, and
root angulation.

in the setting of high risk findings on PANO imagine and a clinical situation dictating operative management (meaning -surg. ext. required) then CT can provide valuable info

the EXACT role and indications for CT imaging for managment of impacted thirds is unclear and evolving

Question 25

comparison of the sensitivity and specificity of PANO vs CT imaging of predicting IAN exposure

Answer 25

The sample was composed of subjects referred for CT imaging secondary to detecting high-risk finding on panoramic radiograph. In this sample, the sensitivity and specificity of panoramic imaging was 70 and 63% respectively. For the CT findings, the sensitivity and
specificity were 93 and 77%, respectively.

Question 26

frequency of root migration in coronectomy procedures - general

Answer 26

majority of papers stated subsequent root migration toward the superior border of the mandible

Question 27

conclusions on coronectomy procedure

Answer 27

when imaging suggests an intimate relationship between tooth and IAN and tooth requires a pathologic reason for removal – this procedure is a consideration

entire crown must be removed and roots left below the alveolar crest

Question 28

role of lingual retraction or lingual flaps in removal of third molars

Answer 28

raising a lingual flap if necessary for selected indicatios - if used right is acceptable
retraction to protect the lingual nerve is imp. and it must remain subperiosteal at all times

Question 29

should anything be placed in the socket following (at the time of) third molar removal? if yes when and to who?

Answer 29

in order to improve periodontal parameters on the distal of the second molar at the time of extraction is not indicated for everyone but something to do or highly consider for HIGH RISK PTS.
high risk patients include 3 main things
1. over age of 26
2. pre-existing periodontal defects (attachment level greater than or equal to 3mm or probing depth over 5mm)
3. horizontal or mesioangular impaction

in studies that looked into this– platelet rich plasma or a resorbable membrane were more effective than no tx in producing a clinically signficant improvement in probing depths on the distal of the second molar

DBP is easiest to use*
non resorbable, resorbable GTR, DP and PRP work in setting of high risk patients

Question 30

incidence of IAN nerve involvement 1-7 days after?
persistent IAN involvment? how long after is persistent?
mean?

Answer 30

after 1-7 days there is around 1-5%

persistent – meaning still present after 6 months is high of .9% to a low of 0.

mean - .3%

Question 31

results / timeline of nerve repair interventions

Answer 31

results are variable - but if carried out between 4.5 - 7 months after surgery, over 50% of patients show some type of improvement
- later repairs - up to over 47 months post injury 0 can still show some signs of repair but less likely

Question 32

incidence of lingual nerve involvement 1-7 days after?
persistent lingual involvement? how long after is persistent?
mean?

Answer 32

The incidence of lingual nerve involvement one day after surgery (excluding the use of lingual flap elevation) varies from 0.4% to 1.5%

The incidence of persistent involvement (still present at six months) varies from 0.5% (with the use of a lingual flap to a low of 0.0%. (Blackburn 1989) Several studies indicate an incidence of 0% persistent paresthesia whether lingual retraction is used or not.

Question 33

long buccal nerve involvement incidence
when is it at risk for involvment?

Answer 33

this nerve is at risk during the initial incision for many third molar procedures
- branches of it are probably frequently cut during the incision process, but the effects are generally not noted

if nerve injury is involved - it is likely because of aberrant anatomical course of the nerve - like coming off the IAN once it was already in the canal and coming out through a separate foramen on the buccal side of the mandible

Question 34

studies have showed spontaneous nerve recovery rate of?
when is improvement regardless of timing post injury poor?

Answer 34

50% to 100% for both IAN and lingual nerves – some papers mention a greater spontaneous recovery rate for the IAN - but not well documented .

all papers indicated that repairs carried out for dysethesia carried a poorer prognosis, whatever timing the surgery was

Question 35

taste recovery findings

Answer 35

most studies suggest that even when lingual nerve repair produces some improvement to tactile sensation, taste sensation does not recover

but two papers did show recovery ad some improvement to taste
(when repaired b/w 4-5.5 months)

Question 36

testing light touch or tactile sensation with von freys hairs looks at which fibers?

Answer 36

a beta fibers and pressure receptors

Question 37

testing two point discrimination tests what?

Answer 37

tests larger myelinated axons

Question 38

testing direction tests?

Answer 38

tests a alpha and a beta fibers

Question 39

testing pinprick sensation tests?

Answer 39

pain sensation
tests a delta and c fibers

Question 40

steps in clinical neurosensory testing of the IAN nerve involvment

Answer 40

1. divide into four quadrants (Upper/Low, L/R)
2. start with control side to est. baseline
3. then alternate right to the injured side to determine comparative (ex. - start in right upper then do left upper, right lower, then left lower – sequence if injured left side)
4. two point discrimination - find threshold on non-injured side first.
5. brush stroke - directional
6. contact detection (start out with smaller one to determine if can tell if it bends) – if injured side does not respond - go up in size (more pressure required to bend the acrylic on injured side is most likely)
7. thermal
8. pin prick – determine if feel sharp or dull

Question 41

mylohyoid nerve orgininates from?
branch of?
innervates?

Answer 41

The mylohyoid nerve is a branch of the inferior alveolar nerve. The inferior alveolar nerve originates from the mandibular branch of the trigeminal nerve. The mylohyoid nerve provides both motor and sensory innervation

sensory / cutaneous innervation to lower / inferior aspect of the chin + first molars mesial root
motor –> mylohyoid muscle and anterior muscle belly of the digastric