3. Deterministic effect of Radiation in tissues
• Radiation damaged cells not replaced by cells of the same
type
• Results in less cellular, more extracellular elements.
• Fibrotic and poorly vascularized tissue with reduced or absent
healing ability.
• Breakdown because – absent cellular turnover
4. damage to vasculature:
- End
arteritis, periarteritis, hyalinisation, fibrosis, thrombosis
of vasculature of periosteum and cortical bone
(periosteal vessels and inferior alveolar artery affected)
aseptic necrosis of involved bone
Severely compromised blood supply differentiates with typical features of
osteomyelitis associated with non- irradiated tissue(such as
sequestra, involucrum).
Sequestration can occur which is rather slow as osteoclastic activity is also
destroyed along with osteoblastic activity.
5. damage to bone due to:
- Osteoblast destruction
- Normal marrow tissue is replaced by fatty marrow
and fibrous connective tissue resulting in
hypovascular, hypoxic, hypocellular marrow tissue
- Reduced degree of mineralisation
6. Radiolysis of water
• Photon + H2O H. + OH.
• H. + O2 HO2
.
• HO2
. + H. H2O2
• HO2
. + HO2
. H2O2
• RH + OH. R. + H2O
• RH + H. R. + H2
7. Dental Extraction after Radiotherapy :
Delayed wound healing
Prolonged alveolar bone exposure
Infection
Osteoradionecrosis
8. OsteoRadioNecrosis is a nonhealing, nonseptic lesion of bone in
which bone volume and density cannot be maintained by the
hypocellular, hypovascular, hypoxic tissue, which cannot
adequately meet its metabolic demands.
Marx 1983 …...
cumulative tissue damage induced by radiation rather than
trauma or bacterial invasion of bone.
Complex metabolic and tissue homeostatic deficiency seen
in hypocellular, hypovascular, and hypoxic tissue.
9. Trauma during extraction
Beumer et al reported that the most common factors associated with ORN were
postradiation extractions (26.5%)
collagen lysis and induced cellular death
This creates a wound with an oxygen
requirement and a demand for the
basic elements of tissue repair that are
beyond the capabilities of the local
tissue to provide for the needs.
10. Pre-Radiation Extractions
The current school of thought - grossly
carious, periodontally "hopeless," or those teeth
deemed to have poor prognosis for retention beyond
twelve months should be removed prior to the
initiation of radiation therapy - this avoids dental
manipulations in the post irradiation period.
11. i. The implications of any dental extractions subsequent
to radiotherapy must be sensitively explained to the
patient.
ii. Extractions should preferably be undertaken up to
three weeks prior to commencement of treatment.
Ten days should be considered a minimum period.
iii. Patients about to undergo bone marrow
transplantation should have any appropriate teeth
removed at the time of the bone marrow harvest.
iv. Children should have all primary teeth within three
months of exfoliation and those with any risk of pulpal
involvement removed.
v. Permanent teeth with a doubtful prognosis should be
removed. It should be borne in mind that permanent
teeth with non-symptomatic periapical lesions are
rarely exacerbated by cancer therapy. Judgement
needs to be made on overall prognosis.
vi. All teeth in direct association with an intra-oral
tumour should be removed.
vii. Teeth should be removed with a minimum of trauma
and if possible primary closure achieved.
Patients are particularly at risk of ORN, when tooth extractions are undertaken
both immediately before and after radiotherapy.
12. Since 1986, the incidence of ORN after preradiation extraction
(3.0 –3.2%; 23 of 711–756 patients) was approximately the same
as the incidence of ORN after postradiation extraction (3.1–3.5%;
16 of 461–508 patients) in pooled studies
Osteoradionecrosis can also occur in edentulous
patients or spontaneously, and preradiation extractions
cannot prevent these.
Michael J. Wahl, D.D.S. Osteoradionecrosis Prevention Myths
Int. J.Radiation Oncology Biol. Phys., Vol. 64, No. 3, pp. 661–669, 2006
13. Post radiation extraction
Although there is no conclusive evidence regarding pre-extraction
antibiotic prophylaxis to prevent ORN, the general consensus would
recommend antibiotic prophylaxis and continued antibiotics until
completion of healing.
Co-amoxiclav / amoxicillin (metronidazole in those allergic to penicillins) are
generally the drugs of choice.
Alcohol free 0.2% chlorhexidine gluconate mouthwash is also
recommended prior to extractions
use of low-adrenaline/adrenaline free local anaesthesia may also reduce
the risk of ORN and as such their use is recommended. Any extractions
completed should be performed with minimal trauma and, where
possible, alveoloplasty with soft tissue primary closure obtained.
Where extractions are required HBOT is recommended both before and
after tooth removal. However, the significant number of ―dives‖ involved
and limited local availability can lead to poor compliance
14. Role of Hyperbaric Oxygen Therapy in Injury Reversal
and as an adjunct during Extraction
• HBO therapy consists of 100% oxygen delivered in a pressurized manner.
• HBO has been used effectively to treat ORN and as an adjunctive
treatment with maxillofacial reconstructive procedures such as dental
extractions, dental implants, and jaw reconstruction in the radiated
patient.
Mechanism Increase blood to tissue oxygen
tension which enhances the diffusion
of oxygen into tissues
Revascularizes the irradiated tissue and
improves fibroblastic cellular density
Limits the amount of non viable tissue
15. HBO prophylaxis as
Treatment of Choice
No evidence of ORN in 47 patients given prophylactic HBO for dental
extraction for 5 yrs after extraction.
Management of dental extractions in irradiated jaws: a protocol with hyperbaric oxygen;
Lambert, P.M., Intiere, N, Eichstaedt, R
Recommendations:
HBO prophylaxis protocol consists of 20 sessions of 90 minutes each
breathing 100% humidified oxygen at 2.4 atm absolute
pressure, given before surgery and 10 similar sessions after surgery.
Extractions performed using elevator and forceps technique under
either local or general anesthesia. A meticulous atraumatic
alveoloplasty routinely performed to achieve a primary mucosal
closure. Reflection of periosteum minimized to the extent possible.
16. Conservative approach without HBO
HBO did not prevent all cases of ORN, and therefore its effectiveness was
less than 100%.
Low- epinephrine or epinephrine-free, nonlidocaine LA
Atraumatic extraction
17. Where possible,
dental extractions should be avoided
in irradiated patients due to the risk of
Osteoradionecrosis;
If necessitating extraction, meticulous
preventive measures
should be undertaken.
conclusion……
18. • The Oral Management of Oncology Patients Requiring Radiotherapy, Chemotherapy and / or
Bone Marrow Transplantation: Clinical Guidelines; The Royal College of Surgeons of England /
The British Society for Disability and Oral Health; Updated 2012
• Evans, Montgomery, Gullane; Principles and practice of Head and neck Oncology; Martin
Dunitz 2003; edition 2006
• Topazian, Golgberg, Hupp; Oral and Maxillofacial Infections; WB Saunders Company, 2002;
4th ed
• Lambert, P.M., Intiere, N, Eichstaedt, R; Clinical controversies in oral and maxillofacial surgery:
Part One. Management of dental extractions in irradiated jaws: a protocol with hyperbaric
oxygen; J Oral Maxillofacial Surg 1997: 55: 268-274.
• Clayman, L; Clinical controversies in oral and maxillofacial surgery: Part two. Management of
dental extractions in irradiated jaws: a protocol without hyperbaric oxygen; J Oral.
Maxillofacial Surg. 1997: 55: No. 3: 275-281.
• Maxymiw WG, Wood RE, Liu FF; Postradiation dental extractions without hyperbaric oxygen;
Oral Surg Oral Med Oral Pathol. 1991 Sep;72(3):270-4.
• Michael J. Wahl, D.D.S. Osteoradionecrosis Prevention Myths ; Int. J.Radiation Oncology Biol.
Phys., Vol. 64, No. 3, pp. 661–669, 2006
• DH Koga, JV Salvajoli, FA Alves; Dental extractions and radiotherapy in head and neck
oncology: review of the literature; Oral Diseases (2008) 14, 40–44
• Greenberg, Glick, Ship; Burket’s Oral Medicine; BC Decker inc. 2008; 11th ed.
• White, Pharoah; Oral radiology: Principles and Interpretation; Elsevier; 6th ed.
References
Editor's Notes
Spontaneous Breakdown of tissue
Severely compromised blood supplyDifferentiates with typical features of osteomyelitis associated with non- irradiated tissue(such as sequestra, involucrum). Sequestration can occur which is rather slow as osteoclastic activity is also destroyed along with osteoblastic activity.No micro organisms present
Leads to gradual devitalisation of bone tissue
Formation of hydroxl, hydro peroxyl radicals and hydrogen peroxide which are oxidising agents>> this indirect effect accounts for 2/3rd of the radiation induced biologic damage; other 1/3rd damage is due to direct ionising of the molecules
Dosage >0. 55 uGy/hr increased risk
Previous authors had described ORN as a triad of Critical RADIATION dose, TRAUMA, INFECTIONInfection is a secondary event
Trauma is one of the several factors involved in the disease. Any insults to mucosa in the form of denture or scaling or fractures or injudicious root canal instrumentation can precipitate the disease.However, ORN can occur spontaneously; amazingly 20% of pre radiation extractions have also developed ORN<<Factors ppt.ing ORNIt is just a risk factor that needs to be eliminated to minimise the chance for occurrence of the disease
Radiotherapy immediately following extraction is of no aid in preventing ORNGuideline regarding extraction
HOWEVER!!! Recent literatures showmodern age of RT, in which megavoltage and super-voltage photons and electrons replaced orthovoltage beams in the mid to late 1960s one finds that there is little difference between the rate of ORN associated with dental extractions before and after RT.
Condition necessitating extractions after radiation therapy