3. RATIONALE
Oral cavity is exposed to large doses of radiation when
radiation therapy is used in the treatment of oral cancer.
Radiation therapy for malignant lesions in oral cavity
indicated when Lesion radiosensitive/advanced
/deeply invasive & cannot be approached surgically.
Radiation treatment administered as many small doses
(fractions).
Typically 2 Gy delivered daily for weekly exposure of 10
Gy.
Radiotherapy course continues for 6-7 weeks until total
60-70 Gy administered.
The complications (deterministic effects) of a course of
radiotherapy on the normal oral tissues result only from
therapeutic exposures, not from radiation levels used for
diagnostic imaging.
5. ORAL MUCOUS MEMBRANE
MUCOSITIS- Reddening and inflammation of oral mucosa
1st Sign of mucositis – end of second week of therapy.
ATROPHY OF RADIOSENSITIVE BASAL LAYER
FORMATION OF WHITE-YELLOW PSEUDOMEMBRANE
SLOUGHING OF MUCOSA
SECONDARY INFECTION DUE TO Candida albicans
(common complication)
HEALING (After about two months)
6. Radiation induced mucositis is initiated by direct injury to basal
epithelial cells and the cells in the underlying tissue.DNA
strands breaks and results into cell death or injury.
7. Clinical Features
Reddish inflamed mucosa
Areas of white pseudo
membrane
Areas where oral epithelium is
separated from underlying
connective tissue
Sores in mouth, gums and
tongue
Dysphagia
Ulcers due to radiation
necrosis
Complications in denture
wearing
8. WHO MUCOSITIS SCALE:
1.Soreness/ Erythema
2.Erythema,ulcers but patient is able to eat solid.
3.Ulcers, requires liquid diet.
4.Food administration is not possible orally.
9. Management
Good oral hygiene
Avoid spicy, hard, acidic and hot food and beverages
TOPICAL ANESTHETICS (required at mealtimes)
-Lidocaine (ointment, sprays)
-Benzocaine (gels, sprays)
ANALGESICS
-Opioid drugs
10. TASTE BUDS
Taste buds sensitive to radiation
Extensive degeneration of normal histological
architecture of taste buds caused by therapeutic doses
2nd-3rd week of Radiotherapy Patients notice loss of
taste acuity
Posterior two-thirds affects bitter and acid flavours
Anterior third affects sweet and salty flavours
Taste acuity decreases by a factor of 1000 to 10,000
during course of Radiotherapy
Alterations in saliva due to radiation changes in
taste perception
Taste loss is reversible , recovery takes 60-120 days
12. SALIVARY GLANDS
Major salivary glands exposed to 20-30 Gy
Parenchymal component of salivary glands
radiosensitive
Marked decrease in salivary flow first few weeks
after initiation of radiotherapy.
Extent of reduced flow dose dependent
may reach zero at 60 Gy.
Mouth dry (xerostomia) tenderness
Difficulty and pain in swallowing
13. Composition of saliva affected.
Increased concentration of sodium, chloride,
calcium, magnesium ions and proteins
Loss of lubricating properties of saliva
Serous acini are more affected as they are more
radiosensitive than mucous.
(Parotid>Submandibular/Sublingual)
14. Viscosity of saliva increases.
pH of saliva decreases Decalcification of
enamel
Compensatory hypertrophy of the salivary gland
xerostomia subsides 6-12 months after
therapy
Xerostomia persisting beyond a year less likely
to return to normal
15. Inflammatory response after initiation of therapy
Loss of acini and ducts
Progressive fibrosis
Adiposis
Loss of fine vasculature
Parenchymal degeneration
17. TEETH
Adult teeth resistant to radiation effects
Developing teeth retarded root development,
dwarf teeth, failure to form one or more teeth
Tooth bud Destruction
Calcified teeth Inhibited cellular differentiation
Malformation Arrested general growth
Pulp decreased vascularity reduced cellularity
Tooth prone to pulpitis
Eruptive mechanism radiation resistant. Irradiated
teeth with altered root formation erupt, even if rootless
Severity of damage dose dependent
18. RADIATION CARIES
Rampant form of dental decay that may occur in
individuals who receive a course of radiotherapy that
includes exposure of the salivary glands
Lesions occur secondary to changes in the salivary glands
and saliva due to :
-decreased salivary flow
-decreased pH of saliva
-increased viscosity of saliva
-decreased lubricating properties of saliva
Patients receiving radiation therapy have increased
Streptococcus mutans, Lactobacillus & Candida
Destruction is seen with doses >30 Gy and is pronounced
when the teeth receive >60 Gy
19. Clinically, 3 types of Radiation Caries seen :
Widespread superficial lesions attacking buccal,
occlusal incisal, & palatal surfaces
Primarily involving cementum and dentin in the
cervical areas. Lesion progresses around tooth
circumference Loss of crown
Dark pigmentation of entire crown
Combination of all these lesions appear in some
patients
21. MANAGEMENT :
-Topical application of 1 %
neutral sodium fluoride (viscous
gel) in custom made applicator
trays
-Combination of restorative
dental procedures, good oral
hygiene, diet restricted in
cariogenic food and topical
application of Sodium fluoride
-Grossly decayed teeth or teeth
with periodontal involvement to
be extracted before irradiation
22. BONE
Mandible or maxilla often irradiated during treatment
of cancers in oral region
Damage to fine vasculature
Primary damage to mature bone
Irradiation
normal marrow replaced with fatty marrow and
fibrous connective tissue
marrow tissue becomes hypovascular, hypoxic,
hypocellular.
Degree of mineralization reduced
Brittleness or altered from normal bone
Endosteum becomes atrophic : lacks osteoblastic
osteoclastic activity
23. OSTEORADIONECROSIS . :-
Definition -Inflammatory condition of bone that occurs after bone
has been exposed to therapeutic doses of radiation given for a
malignancy of the head and neck region.
Decreased vascularity of mandible
infection by microorganisms from the oral cavity
Radiation-induced breakdown of the oral mucous membrane
mechanical damage to the weakened oral mucous membrane
(eg.denture sore /extraction/periodontal lesion/radiation caries)
Bone Infection
Non-healing wound in irradiated bone
difficult to treat.
25. Clinical Features
Mandible >Maxilla
Temporal bone also
affected.
Time period- 7.5 years-20
years
Extra and intra oral fistula
Parasthesia and
anaesthesia
Pathological fracture
26. TYPES:
Early, trauma induced
Spontaneous, without any trauma
Late, trauma induced
AREA OF EXPOSED MANDIBLE AFTER RADIOTHERAPY
LOSS OF ORAL MUCOSA
28. TREATMENT
Debridement
Antibiotic- 2 million units
Supportive therapy
Analgesics- narcotic and non-narcotic drugs
Good oral hygiene
Bone resection.
Hyperbaric oxygen therapy
30. MUSCULATURE
Inflammation and fibrosis of musculature due to radiation
Contracture and trismus of muscles of mastication
Masseter or pterygoid usually involved
Restriction in mouth opening starts about 2 months after
completion of radiotherapy
Management : Physiotherapy may help in increasing
opening distance
31. REFERENCES
ORAL RADIOLOGY (PRINCIPLES AND INTERPRETATION) –
WHITE & PHAROAH
ESSENTIALS OF ORAL AND MAXILLOFACIAL RADIOLOGY –
FRENY R KARJODKAR