Dental Management of the patient undergoing radiotherapy or chemoterapy

PATIENTMANAGEMENT UNDERGOING RADIOTHERAPY OR CHEMOTHERAPY

RADIOTHERAPY ON HEAD AND NECK

Radiotherapy has the ability to destroy neoplastic cells while sparing normal cells. However in practice, normal tissues experience some undesirable effect.

Radiation affected hematopoietic cells, epithelial cells, and endothelial cells soon after radiotherapy begins

Salivary glands and bone are relatively radioresistant, but intense vascular compromise may result in salivary glands and bone damage

RADIATION EFFECTS ON ORAL MUCOSA

Initial effect on oral mucosa (first 1 or 2 weeks) : erythema that may progress into severe mucositis

with or without ulceration

Pain

Dysphagia that may lead to inadequate nutritional intake

Loss of taste

Long term effect: Submucosal fibrosis, which make mucosal lining less pliable and less resilient. So, minor trauma may create ulcerations and take weeks or months to heal

RADIATION EFFECTS ON MANDIBULAR MOBILITY

Radiation may lead : Pterygomasseteric sling and periauricular

connective tissues become inflamed

Muscles become fibrotic and tends to contract

Articular surfaces degenerate

Usually occuring over the first year after radiation therapy and painless

TRISMUS

RADIATION EFFECTS ON SALIVARY GLANDS

Salivary glands damage will result to atrophy, fibrosis, and degeneration → Xerostomia

Xerostomia leads to: Difficulty with tasting, chewing, and swallowing

Sleeping difficulty

Esophageal dysfunction (including chronic esophagitis)

Nutritional compromises

Higher frequency of intolerance to medications

Increased incidence of glossitis, candidiasis, angular cheilitis, halitosis, and bacterial sialadenitis

Decreased resistance to loss of tooth structure from atrition, abrasion and erosion

Loss of buffering capacity

Increase susceptibility to mucosal injury

Inability to wear dental prostheses

Rampant (radiation) caries → decay around the entire circumference of the cervical portion

Increase in oral infections such as candidiasis

TREATMENT OF XEROSTOMIA

Replacement / Stimulation of saliva:

REPLACEMENT

Water

Glycerin (contains several ions in saliva, mimic the lubricating action of saliva)

Carboxymethylcellulose (mucin-based products which animal-derived)

STIMULATION

Sugar-free chewing gum

FDA approved:

Pilocarpine hydrochloride (4 x 5mg / day)

Cevimeline hydrochloride (3 x 30mg / day)

RADIATION EFFECTS ON BONE

Osteoradionecrosis is devitalization of the bone by cancericidal doses of radiation

The bone virtually nonvital from an endarteritis because of elimination of the fine vasculature within the bone.

Continual process of remodeling does not occur (e.g sharp areas will not smooth themselves)

Mandible is denser and poorer blood supply, so mandible is the most commonly affected with nonhealing ulcerations and osteoradionecrosis

Other effects of Radiation

Alteration normal oral flora

Overgrowth of anaerobic species and fungi

This may because of radiation and or xerostomia

Candida albicans commonly thrives, frequently needed nystatin or 0,1% chlorhexidine (Peridex) which has antibacterial and antifungal effects

EVALUATION OF DENTITION BEFORE RADIOTHERAPY SHOULD TEETH BE EXTRACTED? Consideration:

Condition of Residual Dentition

Poor prognosis teeth should be extracted before RT

Patient’s Dental Awareness

Excellent OH → Retain as many teeth as possible

Neglected OH → Will be more difficult

Immediacy of Radiotherapy

Immediate RT: maintain the dentition

Delayed RT: may give time for dental management, need to work closely with the patient

Radiation Location

The more salivary glands and bone involved, the more severe xerostomia and vascular compromise

Radiation dose

Higher radiation dose → more severe normal tissue damage

PREPARATION OF DENTITION FOR RADIOTHERAPY AND MAINTENANCE AFTER IRRADIATION Prophylaxis like topical fluoride application using fabrication

of custom trays

Stop smoking and alcohol consumption

During radiation treatment, should rinse the mouth at least 10x / day with saline

Chlorhexidine mouth rinse 2x / day

The Dentist should control 1x / week

Application of nystatin or clotrimazole (overgrowth Candida albicans)

Monitor ability of mouth opening → physiotherapy exercises

Weighed weekly to determine adequate nutritional status

May be necessary to feed via nasogastric tube

METHOD OF PERFORMING PREIRRADIATION EXTRACTIONS

Concepts of bone preservation are disregarded

Remove a good portion of the alveolar process along with the teeth (using burs or files to smooth the bony edges) and achieve a primary soft tissue closure

Prophylactic antibiotics are indicated

“ The Dentist is in a race against time. If the wound fails to heal, the radiotherapy will be delayed. If the radiation is delivered before the wound heals, healing will take months or even years ”

INTERVAL BETWEEN PREIRRADIATION EXTRACTIONS AND BEGINNING OF RADIOTHERAPY?

No categoric answer

Traditionally: 7-14 days between tooth extraction and radiotherapy

If possible: 3 weeks after extractions

If wound dehiscence has occured, the radiotherapy should be delayed if possible

Daily local wound care with irrigations and post op Antibiotics until soft tissues have healed

IMPACTED THIRD MOLAR REMOVAL BEFORE RADIOTHERAPY

Partially erupted: removal may be prudent, to prevent pericoronal infections

Totally impacted: Keep it remain in place is more expeditious

METHODS OF MANAGING CARIOUS TEETH AFTER RADIOTHERAPY

Must be immediately cared

Full crowns are not warranted because recurrent caries is more difficult to detect

Flouride application

Endodontic intervention with systemic antibiotics

TOOTH EXTRACTION AFTER RADIOTHERAPY

Post irradiation extractions is most undesirable, because the outcome is uncertain

If the tooth is needed to be extracted, perform routine extraction without primary closure or surgical extraction with alveoloplasty and primary closure, both has similar results: a certain concomitant incidence of osteoradionecrosis

Use of antibiotics is recommended

Use of hyperbaric oxygen (HBO) before and after tooth extraction

HBO dives 20-30 before extraction and 10 more after extractions

Usually 1x / day. So, it takes 4-6 weeks to get the 20-30 treatments and 2 weeks of treatment after surgery

Marx et al: Incidence of Osteoradionecrosis of group with use of AB only : AB+HBO = 30% : 5,4%

DENTURE WEAR IN POSTIRRADIATION EDENTULOUS PATIENTS

With denture, patient has the risk of causing ulceration of the mucosa

Soft denture liner may be a solution

Denture fabrication is made once the acute effects of irradiation have subsided

Denturers fabrication must be certain that denture base and occlusal table are designed so that forces aare distributed evenly throughout the alveolar ridge and that lateral force on the denture are eliminated

USE OF DENTAL IMPLANTS IN IRRADIATED PATIENTS The more radiation delivered, the higher the failure rate

for endosseous implants

The longer the duration betweenn radiation treatment and implantation, the higher the failure rate

When implants in irradiated patiens fail, they usually fail early, before prosthetic reconstruction indicating a failure of osteointegration

The combination of radiation and chemotherapy has a particularly negative effect on the outome for osseointegration

Implant survival in irradiated patients tends to he higher in the maxilla than in the mandibule

Shorter implants have the worst prognosis

HBO treatment reduces implant failure rates

MANAGEMENT OF PATIENTS WHO HAVE OSTEORADIONECRIOSIS

Patient should discontinue wearing any prosthesis

Decreased vascularity of the tissues and do not gain ready access to the area to perform the function of Antibiotics

Nonhealing wounds or extensive areas of osteoradionecrosis is needed surgical intervention.

HBO can improve results greatly in conjunction with surgical intervention

DENTAL MANAGEMENT OF PATIENTS RECEIVING SYSTEMIC CHEMOTHERAPY FOR MALIGNANT DISEASE

Antitumor effect of cancer chemotherapeutic agents is based on their ability to destroy or retard the division of rapidly proliferating cells

Normal host cells that have a high mitotic index are affected. Most affected are the epithelium of the gastrointestinal tract and the cels of the bone marrow

EFFECTS ON ORAL MUCOSA

Reduce the normal turnover rate of oral epithelium → atropic thinning, which manifested clinically as painful, erythematous, and ulcerative mucosal surfaces in the mouth.

Changes are seen within 1 week of the onset of antitumor agents

Effects are usually self limiting, spontaneous healing within 2-3 weeks after cessation of the agent

EFFECTS ON HEMATOPOIETIC SYSTEM

Myelosuppression : Leukopenia, Neutropenia, Thrombocytopenia and Anemia

Within 2 weeks the white blood cell count falls to an extremely low level

The oral effect: Marginal gingivitis, and bleeding from the gingiva is common

Overgrowths of oral flora, especially fungi

Thrombocytopenia can be significant, and spontaneous bleeding may occur

Recovery from myelosuppresion is usually complete 3 weeks after cessation of chemotherapy

EFFECTS ON ORAL MICROBIOLOGY

Chemotherapeutic agents → Immunosuppressive side effect → overgrowth of microbes, superinfection with gram (-) bacili, and opportunistic infections

Most patients with chemotherapy are treated with sytemic antimicrobial agents

Frequent overgrowth organism: Candida species

GENERAL DENTAL MANAGEMENT

Chemotherapy has minimal effects on the vasculature, so dental management is easier

Primary concerns: bone marrow suppression

Patient being treated for hematologic neoplasm (e.g leukemia) both the disease and chemotherapy lead to decrease in functional blood elements → risk of infection & hemorrhage

In non hematologic neoplasm, risk of infection & hemorrhage only during the course of chemotherapy

Prechemotherapy dental measures: Prophylaxis

Fluoride treatment

Necessary scaling

Removal of unrestorable teeth

GENERAL DENTAL MANAGEMENT

Dental procedures requirement: WBC ≥ 2000/mm3

At least 20% PMN

Platelet ≥ 50.000/mm3

Prophylactic Antibiotics should be given if chemotherapy within 3 weeks of dental treatment

Removable dental appliance should be left out (to prevent ulceration of fragile mucosa)

TREATMENT OF ORAL CANDIDIASIS

Topical application of antifungal

Or oral rinses, oral tablets, and creams Oral rinses are less efficacy

tablet are most accepted forms

creams are helpful for oral commissures or prosthetic device surfaces

Most common topical medications: Clotrimazole and Nystatin. 4x daily for 2 weeks

Clotrimaazole troches 4 x 5 times a day

Stronger drugs: Ketoconazole or Fluconazole

Other : Chlorhexidine mouth rinse

DENTAL MANAGEMENT OF PATIENTS WITH BIPHOSPHONATE-ASSOCIATED OSTEONECROSIS OF THE JAW (BOJ)

BOJ is a condition of chronically exposed necrotic bone (painful and often infected)

Bone exposure might occur spontaneously or more commonly following an invasive dental procedure

Complains: halitosis, difficulty eating & speaking, extreme pain

The lesions are persistent and do not respond to debridement, antibiotic, or HBO therapy

BIPHOSPHONATES

Biphosphonates are used to treat osteoporosis, malignant bone metastasis, Paget’s disease of bone, and hypercalcemia of malignancy

Biphosphonates also have antiangiogenic properties → tumoricidal

Biphosphonates bind to bone and incorporate in osseous matrix. During bone remodelling the drug is taken up by osteoclasts and internalized in the cell cytoplasm → inhibit osteoclastic function and induces apoptotic cell death

The result: bone becomes suppressed and shows little physiologic remodelling → becomes brittle and unable to reapir physiologic microfractures

CLINICAL SIGNS AND SYMPTOMS OF BOJ

Exclusively affects the jaws

Clinical: ulcer with exposed bone in a patient who has had a dental extraction

May be asymptomatic

May have severe pain (if necrotic bone becoming infected and exposed)

Osteonecrosis often progressive and lead to extensive areas of bony exposure and dehiscence

DENTAL CARE FOR PATIENTS START TAKING BIPHOSPHONATES

Minimize the risk of occurence of BOJ

Provide dental care early in the treatment

Teeth with poor prognosis should be removed before or as early as possible after administration of biphosphonates

Should be delayed for 4-6 weeks after invasive procedures (e.g tooth extraction)

Elimination of all potential sites of infections

Restorative dentistry

Evaluation on prosthodontic appliances (fit, stability, and occlusion)

DENTAL CARE FOR PATIENTS WITH BOJ

Treatment directed for elimminating or controlling pain and preventing progression of exposed bone

Eliminating sharp edges using bur

Attempts to cover exposed bone with flaps may cause more bone exposure and worsening of symptoms with risk of pathologic fracture

NONE are successful : Major surgical sequestrectomies, marginal and segmental mandibular resections, partial and complete maxillectomies and HBO therapy

Use of Chlorhexidine 3-4x/day

If the tooth is unrestorable because of caries → root canal treatment and amputation of the crown may be a better option than removing the tooth unless it is very loose

Relining a denture with soft liner to promote a better fit and to minimize soft tissue trauma

Odontogenic infections treated aggressively with systemic antibiotics

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