3

Question 1

3rd molars Crown Formation ~

Answer 1

14 years •

Question 2

3rd molars Root Formation approximately 50% by

Answer 2

16 years

Question 3

3rd molars Average formation is ——— and as late as —– •

Answer 3

20 years

24 years

Question 4

3rd molars Position does not change substantially after

Answer 4

25 years

Question 5

Theories behind impacted 3rds

Answer 5

Differential root growth between mesial & distal • Inadequate arch space • Dental development lags skeletal development • Obstruction secondary to cyst, tumor, supernumerary teeth

Question 6

Winter’s Classification •

Answer 6

Based on inclination of impacted tooth to long axis of 2nd molar • 1. Mesioangular • 2. Distoangular • 3. Horizontal • 4. Vertical
Dent

Question 7

Patient Selection “Ideal” •

Answer 7

2/3RD root formation • 18-25 year old • Healthy • No psychological contraindications • No job restrictions to “numb lip”

Question 8

Contraindications to removal of 3rd molars •

Answer 8

Extremes of age: Young age: mandible may grow to accommodate 3rd molars
Old age: most common contraindications for removal

Question 9

Old Age, > 40 •

Contraindications

Answer 9

Highly calcified bone • Less flexible bone • Recuperate more slowly • Increased tendency toward mandibular fracture • Increased tendency toward non-resolving parasthesisa • Increased tendency toward infection - osteomyelitis

• If the tooth has been retained without sequellae, it may be less likely for problems to develop • Monitor with panoramic x-ray every 1-2 years • Surgical intervention for clinical symptoms or radiographic signs
• No sign of caries, periodontal disease, or cystic degeneration, and/or > 4mm of overlying bone • May defer removal unless symptomatic

Question 10

Most likely teeth to be impacted

Answer 10

Mn 3rds > Mx 3rds > Mx Canine > Mn PM > Mn Canine > Mx PM > Mx CI > Mx LI > Mn 2nd molar
• Max canine Canine Due to crowding from adjacent teeth & difficult route to erupt

Question 11

Maxillary Canine • Techniques for Exposure

Answer 11

• Incision usually sulcular • Open vs Closed

Question 12

DESIGN PARAMETERS FOR SOFT TISSUE FLAPS

Answer 12

• Base broader than free margin: blood supply allows inflow of arterial blood and outflow of venous blood – Adequate size – Visibility key

• Incision over intact bone
• Avoid injury to vital structures
• Releasing incision, if needed, to avoid tearing
DESIGN PARAMETERS FOR SOFT TISSUE FLAPS • Adequate Size: DON’T work in a hole
– Visualization: If you can’t see it well, you can’t do it well
• Elevation over intact bone – flap margin should NOT rest over an osseous defect
• Prevent tearing (sharp incision heals better than tear)

Question 13

Vertical (Oblique) Releasing Incision

Answer 13

– Permits soft tissue reflection without tearing
– Oblique – base is broader than apex
– Cross gingival margin at the line angle of the tooth
– Incision over intact bone, but not on osseous prominence

Question 14

TYPES OF MUCOPERIOSTEAL FLAPS

Answer 14

1. Envelope Sulcular in dentate patient Crestal in edentulous area 2. Three cornered flap Single vertical (oblique) release 3. Four cornered flap Two vertical releasing incisions
   TYPES OF MUCOPERIOSTEAL FLAPS
2. Semi-lunar Limited use for periapical surgery 5. “Y” incision Limited use for access to bony palate for torus removal

Question 15

PRINCIPLES OF SUTURING •

Answer 15

Penetrate tissue with needle perpendicular to tissue • Follow curvature of needle as you pass it through the tissue

Question 16

When to leave root tips

Answer 16

LEAVING ROOT TIPS? • Small piece- <4mm
• Deeply embedded in bone
• Not an infected tooth – not pulpally or periapically involved
• Not mobile

When attempted recover will do more damage than good.