Oral Complications Associated with Radiation, Chemo, and Antiresorptive Meds Flashcards
How many Grays of radiation causes ORN in an area?
Greater than 50 Grays
What are the 2 ways radiation is delivered?
Fixed Beam Radiation
Intensity Modulated Radiation Therapy (IMRT)
All the tissue between the portals receives the same
dose
Fixed Beam Radiation Therapy
A constantly moving beam administers different
amounts of radiation to the tissues
The tumor receives the highest amount of
radiation.
Minimal amounts of radiation are applied to vital
structures. (spinal cord, salivary glands)
Intensity Modulated Radiation
Therapy
The application of radiation therapy in smaller
consecutive doses to minimize the lethal effects and limit
the side effects of the therapy.
The dose is usually administered 5 times a week for 5 to
7 consecutive weeks.
Fractionation
What are the 5 R’s of fractionation?
Repair Redistribution Repopulation Reoxygenation Radiosensitivity
(5 R’s of fractionation)
Radiation causes sub-lethal damage to normal and
malignant cells
The repair pathways are often blocked or impaired in the
malignant cells resulting in cell death.
Repair
(5 R’s of fractionation)
DNA is more sensitive during certain stages of cell
replication. (G2 and M phases)
Most stable (S phase)
Fractionation provides multiple opportunities to affect
the cells when they are in the sensitive phase.
Redistribution
(5 R’s of fractionation)
Rapid repopulation of the malignant cells can occur
approximately 4-5 weeks after the initial radiation dose.
Fractionation over 5-7 weeks prevents the rapid
repopulation of these cells
Repopulation
(5 R’s of fractionation)
Tumor cells are more resistant to radiation in hypoxic
environments
Fractionation increases the odds that that tumor cells will
be in a nutrient field during radiation
The outermost tumor cells are destroyed exposing the
“hypoxic”inner layers of tumor cells
Reoxygenation
(5 R’s of fractionation)
Involves the recognition of certain proteins, receptors
and kinases that may make cells less sensitive to
radiation
Recognizing the presence of the components may help
predict the success of radiation therapy in certain cases
Radiosensitivity
Indications for _____ Prior to Radiation Therapy
Non-restorable caries or high caries rate
Periodontal pocketing > 5mm
Furcation involvement
Impacted teeth
Extractions
Which salivary gland is spared the most in radiation therapy? What type of saliva does it produce?
Sublingual; mucous saliva
Hypofunction can occur when exposed radiation
doses as low as 25 Gy
Serous glands are more sensitive to radiation than
mucous glands
Xerostomia
Are serous or mucous salivary glands more sensitive to radiation?
Serous glands
The rapid formation and
progression of dental caries is
mainly attributed to the reduced
quality and quantity of the _____
saliva.
Sugar alcohol originally derived from birch trees
Commercially produced from corn cobs (xylan)
Caries causing bacteria are unable to metabolize it
Xylitol
Ingesting 6-8 grams daily can decreased caries
Frequency of use more important than quantity
Available as a packaged sweetener or in gums, mints,
candies and oral rinses
Xylitol
How. many grams of xylitol need to be ingested each day to get anti-caries effect?
6-8 g
Can cause gastric issues with some pts
Primarily when over 50g ingested/day
Extremely toxic to dogs (pancreas issues)
Xylitol
Cholinergic agonist Pilocarpine hydrochloride 5-10mg tid Max dose 30mg/day May take 12 weeks to see results -Side effect of med is salivary effects not primary effect
Sialogues
5-10mg tid
Max dose 30mg/day
May take 12 weeks to see results
-Side effect of med is salivary effects not primary effect
Pilocarpine hydrochloride
Rinse, brush, floss, fluoride trays
10 minutes/day
No food or drink for 30 minutes
Best results when used prior to bedtime
Fluoride Therapy
What type of fluoride is better for root caries but can stain the teeth brown?
Stanous fluoride
Oral mucosa exposed to radiation becomes
edematous, erythematous, and ulcerated.
The condition can be extremely painful and cause
issues with mastication and swallowing.
The signs and symptoms often arise after the
second week of therapy and may last a few weeks
after the completion of treatment
Mucositis
Mild Pain Maintain oral hygiene Use bland oral rinses Baking soda/water With/without salt Use topical oral pain management Caphosol Magic Mouthwash Viscous lidocaine, Maalox, diphenhydramine With/without nystatin Mild analgesics (OTC)
Mucositis tx
Diphenhydramine 12.5mg/5mL 1 part (120mL)
Maalox 1 part (120mL)
Viscous Lidocaine 2% 1 part (120mL)
Nystatin Susp. 100,000 U/mL 1 part (120mL)
(Optional)
Magic mouthwash used for mucositis
Moderate pain Addition of moderate strength opioids Hydrocodone and oxycodone Altered diet (soft) Severe pain Addition of strong opioids Oxycodone, morphine, oxymorphone May need nasogastric or PEG tube
Mucositis tx
Radiation results in vascular changes in the bone
limiting the blood supply and the ability to heal
after trauma or extractions
Associated with radiation doses above 50 Gy
More common with the mandible
Osteoradionecrosis (ORN)
Is Osteoradionecrosis (ORN) more common in max or mand?
Mand