What are the risk factors for osteoradionecrosis (ORN), in a xerostomic radiation-treated patient, if extractions are required?
This question was submitted to us by a general dentist: If extractions are required, what are the risk factors for osteoradionecrosis (ORN) in a xerostomic patient with rampant decay two years after the successful treatment of their head and neck cancer (radiation, chemotherapy and surgery)?
Dr. Jeff Chadwick, at Princess Margaret Hospital, Dental Oncology, Ocular, and Maxillofacial Prosthetics Group, provided a preliminary response to this question:
With the numerous comorbidities associated with head and neck radiation (oral mucositis, radiodermatitis, dysgeusia, dysphagia/odynophagia, trismus, and xerostomia), arises a critical issue with tooth extraction is the altered biology of the maxilla and mandible due to therapeutic radiation exposure. The treatment results in osseous hypovascularity, hypocellularity, and hypoxemia.
Prior to performing any extractions on radiation-treated patients (head and neck), vital information must be considered, including:
1. General Medical History/Medication History/Social History and other impediments to wound healing
- Diabetes Mellitus
- Renal/Hepatic Failure
- Immunocompromised/Immunosuppressed
- Continued Tobacco Use
- Autoimmune Disease
- Age
- Malnutrition
- Alcohol Abuse
2. Oncology History
- Original diagnosis
- Date of diagnosis and treatment
- Treatment Centre/Radiation Oncologist
- Any ongoing therapy (if applicable)
- Treatment delivered (Radiation/Chemotherapy/Surgery)
- Type of surgery
- Constituents and duration of chemotherapy
- Type and duration/dose of radiation (# of fractions/# Gray [Gy])
3. Clinical history of current dental issues
- Subjective history of pain/swelling/fever/temperature sensitivity/oral fetor
- Clinical examination
- Radiographic examination
If it is determined that the source of infection or rampant decay was in the field of radiation (See Note below), the risk of ORN is significant once the relative dose climbs above 50Gy. It is at this point that the practitioner should consider the following:
1. Refer patient back to the Department of Dentistry at the original treatment site (if possible) for treatment.
2. Place amalgam fillings, if teeth are restorable, wherever possible.
3. Consider endodontic treatment, if certain teeth are beyond restoration, leaving roots in situ and allowing them to passively erupt.
4. If a tooth is not amenable to endodontic therapy (vertically fractured, exceptional canal anatomy), you could consider extraction with attention given to the following:
- Pre-extraction/post-extraction antibiotic prophylaxis
- Conservative surgical approach (avoidance of bone removal/flap elevation)
- Post-operative use of Chlorhexidiene 0.12% rinse twice daily until mucosal coverage is achieved
- Vigilant, frequent, follow-up and monitoring of the healing process
- If multiple teeth require extraction, they should be performed one or two at a time to allow for the completion of the initial stages of healing (this avoids multiple anatomic sites with post-extraction complications)
Ideally, prior to the commencement of a course of head and neck radiation, patients will have been meticulously examined for dental disease by the staff dentists at their respective cancer centres. While there are many conditions that are commonly observed in private practice, any source of infection (including, but not limited to: caries, odontogenic, periodontal) must be treated prior to radiation therapy to reduce peri/post-radiation complications. The conscientious practitioner must identify and prevent dental problems before the patient is faced with the prospect of full-mouth clearance (see Figures 1, 2 and 3).
Figure 1: Patient with a T3N0M0 squamous cell carcinoma of the right oral tongue for radiation therapy (pre-radiation)
Figure 2: 8 months post-radiation therapy without the daily use of topical fluoride gel (extensive and generalized decay can be appreciated)
Figure 3: 12 months post-radiation – Several sessions of extractions have occurred leaving four teeth in situ which were extracted at a later date
For dentate patients, a rigorous oral hygiene and maintenance program is mandatory and includes more frequent follow-up, scaling, oral hygiene re-instruction as well as more frequent radiographic surveys. Patients must also be placed on a regimen of 1.1% neutral pH sodium fluoride gel treatment delivered using custom “mouth-guard” type trays on a daily basis for the remainder of their lives to aid in the reduction of post-radiation decay secondary to radiation-induced xerostomia. In virtually all cases, once a patient has completed cancer treatment and the acute effects of radiation have subsided, they will be referred back to their general dentist for regular care.
Note: You can verify if the source of infection or rampant decay is in the field of radiation, if you contact the patient’s radiation oncologist. Then, they may consult their dosimetry report which would show the dose of radiation delivered to the tooth-bearing portions of the maxilla/mandible.
Follow-up: What further information would you like on this topic? Email us at jcdaoasis@cda-adc.ca
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You recommend amalgam restorations when possible. Are resin reinforced glass inonomer restorations, i.e. geristore, contraindicated for Class V cervical restorations. If yes, what is the rationale ?
As with many questions related to this patient population: “it depends.” The use of RMGI restorations for Class V cervical restorations is not contraindicated. That being said, if your patient is not compliant with their daily application of neutral pH NaF using their custom appliances, the type of restorative material you choose is inconsequential as even the best placed fillings are very likely to fail. Another important factor to consider when choosing a restorative material for these lesions is the type of fluoride that the patient is applying (i.e. neutral pH NaF versus AFP). As reported in the literature (McComb et al, 2002 and Wood et al 1993), AFP can degrade the surface and marginal integrity of GI and RMGI restorations, which can lead to recurrent decay even with daily fluoride use. Additionally, in a xerostomic environment without the buffering capacity of saliva (whether or not fluoride is being used in the desired manner), the milieu around these cervical regions is already acidic and there exists the opportunity for the marginal degradation of GI/RMGI products. The bottom-line for the placement of ANY restoration in this patient population is the daily use of their prescribed NEUTRAL pH fluoride gel to prevent further/recurrent decay with vigilant and frequent recalls/OHI to catch these types of issues when they are small and can be managed in a conservative fashion.
This question was submitted to JCDA Oasis Discussions:
If a post-irradiated patient has an acute infection surrounding a tooth in lower jaw, should the oral surgeon treat the active infection before extracting the tooth? In this example, the patient does not have osteonecrosis prior to extraction of the tooth, but did have a high level of radiation treatment to the lower mandible for squamous cell cancer.
This decision is largely up to the oral surgeon and, as is common with the clinical difficulties that plague this particular patient population, there is rarely a clear solution that is not without some risk.
To answer this specific question, pre-operative antibiotics can be considered prior to the extraction of teeth that were in the field of a relatively high dose of radiation. While there is a plethora of literature supporting their use as an adjuvant measure to reduce the risk of the development of ORN, no definitive guidelines exist and it remains the provider’s choice.
It may be worth considering alternative therapies for this issue as it is unclear from the information given as to whether or not this is an odontogenic infection (nor is this the forum to have such a discussion).
As always, the careful examination of the patient’s symptomatology and acquisition of an accurate diagnosis (diagnosis > treatment; pants first, then shoes) is paramount to selecting the optimal therapy as definitive treatment, such as a dental extraction, is not without risk in patients who have received radiation for a malignancy in the head/neck region. If extraction is the only way to go in the eyes of the provider, the use of the most “atraumatic” procedures and frequent monitoring post-extraction should be sought.
When I initially commented I clicked the “Notify me when new comments are added” checkbox and now each time
a comment is added I get four e-mails with the same comment.
Is there any way you can remove me from that service?
Appreciate it!
Hello Loyd, can you please send me your email address? I think we have a solution for you.
JCDA Oasis
Hi, Thanks a lot for the article, very nicely explained. Although tooth extractions seem to be the main risk factor