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What types of blood vessels are effected most by radiation?
capillaries and arterioles; causes swelling, degeneration and necrosis of the endothelium
Place in the correct order the pathophysiologic sequence of radiation induced wound healing defect
A Trauma induced or spontaneous tissue breakdown
C Development of hypervascular hypocellular hypoxic tissue
D Nonhealing wound
B D A B
(this multiple choice question has been scrambled)
What is 3 H tissue?
Hypovascular, Hypocellular Hypoxic tissue, induced by radiation
The circular pattern of radiation injury establishes an injury pattern of gradual _______ gradients.
Which type of radiotherapy is most common?
Which of the following is NOT a treatment for acute radiation mucositis?
antibiotics; peridex is used to reduce bacterial colonization of ulcers
Radiation mucositis is self limiting, in that it develops in the last ___ weeks of treatment and may extend for ____ month(s) after therapy.
what are three characteristics of radiation mucositis?
- diffuse erythema w/ pain
- mucosal ulcerations
- fibrous exudate
- self limiting
Which describes radiation caries
hard and brown
hard and black
soft and brown
soft and black
hard and black
A direct path of _______ cGy or greater puts one at risk for radiation caries, at which point even the best oral hygiene, dental care and fluoride will not prevent all caries.
what is the etiology of radiation caries.
pulpal necrosis and odontoblast death
What locations would you expect to see radiatio caries on a patients cental incisors?
incisal and gingival margins
Rad induced Xerostomia
what is a preferred treatment?
Pilocarpine 10 mg TID
Pilocarpine 5 mg BID
Pilocarpine 10 mg BID
Pilocarpine 5 mg TID
Pilocarpine 5 mg TID, improves mouth moisture in about 70% of patients
what are the conditions that cause caution for using pilocarpine to relieve radiation xerostomia?
- Pts with:
- heart block
- meds that slow HR or conduction
why is the mandible and associated teeth more susceptible to radiation compared to the maxilla?
mandible is more dense bone to absorb more radiation and has less blood flow
What teeth should be removed before radiation therapy?
teeth with apical pathosis or periodontally involved
those in mandible in direct path of 6000 or greater radiation
ideally how long of time should be given post extractions before starting radiation therapy
at least 21 days
A patient undergoing radiation therapy presents with pain and acute apical abcess # 30. What is the best treatment?
Endo with IND, Ab
endo tx and Incision and drain, antibiotics, once rad therapy has started must avoid invasive methods of treatment
what is the "golden window"
the 4 months after radiation tx when you may do extractions and other definitive care without requiring hyperbaric oxygen therapy.
tissues have recovered from acute hyperemia but inflammation hasn't yet started the 3 H tissue associated with non healing (hypovascular, hypocellular, hypoxic)
Hyperbaric oxygen therapy involves giving 100 percent oxygen to a patient in an environment of pressure equal to that of being ____ feet below sea water
45 (oxygen given at 2.4 atmospheres of pressure)
The 3H tissue that begins at 30 percent of normal vascularity can be expected to realize an increase to ___ percent of normal vascularity
What types of cells are responsible in stimulating the revascularizationn process during HOT? what do they secrete?
macrophages secrete VEGF
Prior to surgery, what is the protocol for hyperbaric oxygen therapy
10 sessions at 2.4 ATA for 30 minutes
20 sessions at 2.4 ATA for 90 minutes
10 sessions at 2.4ATA for 90 minutes
20 sessions at 2.4 ATA for 30 minutes
20 sessions at 2.4 ATA for 90 minutes prior to surgery
how many sessions of HBO therapy at 2.4 ata for 90 minutes should there be after surgery?
at what frequency should HBO therapy occur?
5-6 times per week
Name 5 relative contraindications for HBO tx
Hx of surgery for O
Hx of O N
- URI and chronic sinusitis
- seizure disorder
- emphysema with co2 retention
- high fever
- history of surgery for Otosclerosis
- congenital Sherocytosis
- History of Optic Neuritis
name the 3 types of ORN
- early trauma induced
- late trauma induced
You have extracted a symptomatic tooth during a period of radiation therapy for a patient. what kindof ORN could result
early trauma induced
spontaneous ORN occurs when dosage is above _____ cGy or more
7200 (6000 was risk level for radiation caries)
a patient received rad tx 10 years ago w/ no complications, except caries and dry mouth. you extract a tooth without HBO tx and the socket fails to heal, and bone exposure continues with pain and an osteolytic process.
late trauma induced ORN
The HBO protocol for pre surgery was 20 sessions at 2.4 ATA for 90 minutes.
What is the protocol for HBO tx for ORN?
30 sessions at 2.4 ata for 90 minutes , followed by 10 sessions after an assessment or surgery.
remember, the focus of HBO is not the dead bone, but the rad injured bone not yet dead
Stage III treatment of ORN includes stage II non responders and those that present with:
O to I
- pathologic fracture
- orocutaneous fistula
- osteolysis to inferior border of mandible
a patient is considered a stage I non responder if exposed bone is unchanged after ___ HBO sessions