67.Maxilla_Mandible FRACTURES

Question 1

what is the major anatomical difference between the mandible and other long bones

Answer 1

the mandible does not have a medullary cavity (thus no hematopoetic cells)Mandible has a mandibular canal with inferior alveolar neurovascular structures

Question 2

Tension and compression surfaces of the mandible

Answer 2

tension–alveolar margincompression–ventral mandibular border*important for implant placement! for neutralization, place near alveolar bone margin

Question 3

main or primary force acting on the mandible

Answer 3

bendingmore rostrally, rotationalat the ramus, shearing

Question 4

3 maxillofacial buttresses

Answer 4

rostral (medial)–nasomaxillary*lateral–zygomaticomaxillarycaudal–pterygomaxillary**Lateral is most importantrarely fix caudal buttressincisive bones are NOT part of the buttress and thus rarely need to be fixed

Question 5

Define minor and major tooth root contact with screw

Answer 5

major > or = 50 % screw diameter penetrating tooth rootminor < 50% screw diameter penetrating tooth root

Question 6

Miller et al 2011 Veterinary Surgery article compared pullout of SOP and LCDCP

Answer 6

SOP (plate screw construct) had a higher perpendicular load to failure than a LC-DCP screw construct

Question 7

Baram et al 2008 Veterinary Surgery article concluded CT was superior than radiographs when evaluating traumatic maxillofacial/mandibular trauma EXCEPT FOR

Answer 7

occlusion/malocclusionmandibular body fractures

Question 8

dental formula DOG

Answer 8

maxilla 3142mandible 314342 total

Question 9

dental formula cat

Answer 9

maxilla 3131mandible 312128 total

Question 10

mandibular fixation techniques

Answer 10

–Oral splints–Interfragmentary/intraosseous wires (with 2nd stabilization wire ventral)–Plates (miniplates, SOP, Recon, LCDCP, DCP) with 2nd stabilization plate–ESF (mandible NOT maxillary fractures)

Question 11

Thread pitch necessary for adequate bone purchase

Answer 11

adequate bone purchase requires to be AT LEAST = to bone thickness for neutralization (adequate for mini plate application of maxilla)AT LEAST 2x bone thickness for compression

Question 12

T/F increased frequency of complications with fracture healing has been observed when teeth are removed

Answer 12

TRUEremoval of teeth is not advised

Question 13

sequence of repair in patient with multiple mandibular and maxillary fractures

Answer 13

usually mandible firststart caudal to rostralstabilize mandibular symphysis lastalign occlusion relative to mandible to fix maxilla (lateral buttress first)