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The relationship between dental disease and radiation necrosis of the mandible
oral surgery oral medicine oral pathology withsections Onendodontics anddental radiology Volume
49, Number
2, February,
1980
oral surgery Editor: ROBERT B. SHIRA, D.D.S. School of Dental Medicine, Tufts University 1 Kneeland Street Boston Massachusetts 02 111
The relationship between dental disease and radiation necrosis of the mandible Christopher G. Murray, M.D.,%., MSc., F.R.A.C.D.S.,* Stuart 0. Zimmerman, Ph.D.,*** Houston, Texas UNIVERSITY INSTITUTE,
OF TEXAS AND
SYSTEM
UNIVERSITY
CANCER
CENTER,
M.
OF TEXAS
HEALTH
SCIENCE
Thomas E. Daly, D.D.S.,**
D. ANDERSON CENTER,
HOSPITAL
AND
DENTAL
BRANCH
and
TUMOR
Preirradiation panoramic radiographs of forty-six dentate patients were examined for the presence of significant dental disease. The occurrence of necrosis of the mandible after these patients received radiation therapy was then determined. Evidence of a positive association between dental disease present before radiation therapy and subsequent necrosis of the mandible was found (p = 0.09), leading to a recommendation that significant disease be eradicated before irradiation of oral tissues. Two cases are reported to illustrate the complications that can arise in dentate patients following radiation to the oral cavity. Considerable suffering results from bone necrosis, which can be reduced by careful and rational dental diagnosis and treatment
0
steoradionecrosis may occur after radiation damage to the cells of the bone and its vascular components. It is not known which cellular element is primarily injured, but the end result, osteoporosis leading to radionecrosis, may be expected following aggressive radiation treatment of oral cancer. ’ This research was supported in part by Grant CA 11430 and Contract NOl-CN-75175. National Cancer Institute. *Resident, Maxillofacial Prosthetics, Department of Dental Oncology. Present address: 10th Floor, Coates Building, 20 Collins St., Melbourne, 3000, Australia. **Professor of Dental Oncology. Department of Dental Oncology. ***Professor. Department of Biomathematics. 0030-4220/80/020099+06$00.60/0
0
1980
l-be C. V. Mosby Co.
The role that dental disease plays in the occurrence of bone necrosis following irradiation is uncertain. Bragg and associates* stated that clinical radiation necrosis of the mandible was associated with open mucosal wounds in nearly all cases. Soft-tissue necrosis frequently precedes bone necrosis, and a break in the integrity of the gingival tissues can also provide an entrance by which infection can reach the bone.3 Dental disease is the usual cause of disruption of the gingival crevicular tissues. Periodontal disease, dental abcesses, extensive dental caries, and impacted teeth may all provide a pathway for infection to reach mandibular bone whose reparative capacity has been im99
100
Murray, Daly, and Zimmerman
Oral Surg. February, 1980
Fig. 1. Case 1. Preirradiation panoramic radiograph.
Fig. 2. Case 1. Panoramic radiograph taken 18 months after irradiation showing rampant radiation caries, advancedperiodontal disease,and bone necrosis.
paired by the effects of irradiation.d The presence of microorganisms associated with these dental diseases in the irradiated field increases the probability of the compromised bones being infected. Dental disease situated beyond the actual field of radiation may also provide a focus of infection. Patients with teeth have more than twice as great a chance of developing necrosis as patients who are edentulous. This difference, which has been reported as significant at the p = 0.001 level,j suggests that a further decrease in the incidence of necrosis may be obtained by paying closer attention to the role that dental elements play in the necrotic process. With the radiotherapeutic techniques currently favored at M. D. Anderson Hospital and Tumor Institute, it appears that an over-all base rate of necrosis of about 12 percent can be predicted for edentulous patients. It is hoped that careful consideration of the role that teeth play in the occurrence of mandibular necrosis will permit the incidence of necrosis to be reduced from the reported 24.2
percent to a level closer to that found in edentulous patients. A natural den&ion is clearly beneficial for the irradiated cancer patient, but the potential hazards of retaining the dentition should not outweigh the advantages. This report describes a radiographic survey designed to determine the association between dental disease existing before irradiation and subsequent mandibular radiation necrosis. Two cases in which dental disease appeared to influence the pathogenesis of necrotic disease are also reported. MATERIALS
AND METHODS
From July, 1971, to December, 1975, 104 patients with malignant neoplasms of the floor of the mouth and retromolar trigone received initial treatment at M. D. Anderson Hospital and Tumor Institute, primarily with radiation. These tumor sites were selected for their proximity to the dentition so that any association between dental status and development of osteoradio-
Relationship between dental disease and radiation necrosis
Volume49
101
Number 2
Fig. 3. Case I. Panoramic
radiograph
taken 36 months
after irradiaton
showing pathologic right mandibular
fracture. Table I. Association between dental diseaseand radiation necrosis of the mandible in forty-six
patients irradiated for malignant tumors of floor of mourb and retromolar trigone Radiation necrosis +
Dentaldisease
+ -
IO 6 16
Total
II 19 30
21 25 46
0.09 p (10/16,1l/30) Sensitivity(tO/21)= 47.6% Spekificity(19/25)= 76.0%
necrosis would be apparent. Dentate persons were selected, and panoramic radiographs taken prior to radiation were examined. Forty-six radiographs were available for assessment. Hayward and co-authors” suggestedthat the decision to remove teeth before radiation therapy should be basedon the following criteria: (1) extensive caries, (2) moderate to advanced periodontal involvement, (3) lack of opposing teeth and consequentloss of function and self-cleansing action, (4) partial impaction or incomplete eruption, and (5) extensive periapical lesions. These factors were considered an acceptable basis for separatingthe preirradiation radiographs into those that revealed one or more of thesecriteria and thosethat did not. It was postulated that if a positive correlation existed between dental disease and osteoradionecrosis, this first
group of patients would be at risk by virtue of their dental status. The forty-six films were grouped without prior knowledge of subsequentnecrotic episodes, and the results were examined to determine the association
Fig. 4. Case 1. Intraoral view demonstratinglimited mandibular opening, intraoral hemorrhage, and poor dental status.
between dental pathosis and necrosis of the mandible occurring after radiation therapy. RESULTS Table I indicates the association between significant dental disease and mandibular radiation necrosis. From Table I the following statistical data were derived: p (dental disease/no dental disease) = 0.09 Sensitivity = 41.6% Specificity = 76.0%
Two cases illustrate the association between dental disease and osteoradionecrosis. CASE REPORTS Case 1
A 59-year-old Caucasian man was seen with a squamouscell carcinoma, stage T,N,, located in the right base of the tongue.
102
Murray, Daly, and Zimmerman
Oral Sure. February,198’0
Fig. 5. Case 2. Panoramic radiograph taken before the preirradiation removal of all lower teeth Dantal status
This patient had a history of dental neglect and poor oral hygiene. Alveolar bone loss was apparentaround most teeth, associatedwith chronic periodontal disease.Painless, draining peri’apical abscesseswere present on 41 and dental caries was present in 81678 (Fig. 1). It was decided that the existing dental situation did not warrant delaying radiation treatment. Oral prophylaxis and oral hygiene instruction were administered. A tongue and cheekguard was provided to protect the soft tissues from rubbing against the dentition, and 1 percent sodium fluoride was prescribed for daily application to the dentition via vacuum-formed polystyrene carriers. Fbdiation therapy
The tumor dose was 6,500 rads. The first 5,000 rads were delivered by photons from a cobalt-60 source using parallel opposedfields and a 2: 1 loading to the right side. A further 1,500 rads were given by an interstitial implant of radium needles 2 months after initiation of the external beam treatment. Postimadiation
progress
Six months after initiation of radiotherapy, the patient reported that he was not using fluoride regularly and his oral hygiene was poor. Despite further instruction, the oral situation at 12 months had deteriorated, and by the end of 18 months rampant radiation caries and bone necrosiswere present (Fig. 2). An asymptomatic 2 by 1 cm. area of bone was exposed on the lingual aspect of the right mandible in the molar region. Systemic antibiotics and neomycin mouth rinses were prescribed, and oral hygiene instruction was given. By the end of 22 months a purulent dischargewas draining from the gingival sulci of many teeth, particularly in the lower right molar region. The lower right secondmolar was extremely mobile but asymptomatic. Necrotic bone was removed from the right mandible and the patient was further counseled regarding oral hygiene. By 24 months the lower tight second molar had been sequestrated.Ten months later the fluoride treatments had been discontinued and radiation
decay was progressing.Extensive bone necrosisof both cortical plates of the right mandible was evident. The patient was unresponsive to advice. At 36 months mandibular fracture occurred through the lower right second molar region, accompanied by hemorrhage. A large hematomawas present in the tissues of the right cheek, and trismus of the massetermuscle restricted mandibular opening (Figs. 3 and 4). Five days after the initial hemorrhagic episode, the patient underwent a tracheostomy, resection of the right mandible, and ligation of the external maxillary artery. Case 2
A Caucasian woman was 55 years of age at the time of presentation with a squamous-cell carcinoma, stage TaN,, located in the oral tongue. Dantal status
This patient had sought dental treatmentat irregular intervals, and her oral hygiene was describedat the initial examination as “fair. ” Periodontal diseaseinvolved the remaining dentition, particularly the lower anterior teeth (Fig. 5). Before commencing irradiation, we decided to extract all teeth in the lower dental arch and the upper incisors, which were pariapitally involved. The remaining teeth were managed in the samemanner as described for Case 1. Radiation therapy
The tumor dose was 6,000 rads. The first 5,000 rads were delivered by photons from a cobalt-60 source using parallel opposedfields. An additional 1,000 rads were given by a 7 MeV electron beam. The treatment time was 2 months. Postirradiation
progress
Nine months after the start of radiation treatment, the patient complained of pain in the upper left second premolar. Advanced periodontal diseasewas presentaround the remaining teeth, and the premolar pain was attributed to that. Oral hygiene was poor and there was inflammation of the lower right alveolus where the upper right molars contracted. The patient was further instructed in oral hygiene proceduresand a
Volume49 Number2
Relationship betweendental disease and radiation necrosis 103
Fig. 6. Case2. Panoramicradiograph taken 27 months after irradiation showing mandibular necrosis at the site of contact of the unopposed upper right molars.
polystyrene mouth guard was fabricated to reduce trauma to the edentulous right mandible. At 22 months, exposed necrotic bone was evident on the right mandible where the polystyrene mouth guard on the upper teeth madecontact. Antibiotics were prescribed. By 27 months a larger area of necrotic bone was visible, and pus was draining externally via a sinus below the right mandible
(Figs. 6, 7, and 8). The area was irrigated, oral hygiene instruction was given, and a further course of antibiotics was prescribed. The final outcomeof the progressivenecrotic disease in this patient is not known. DISCUSSION
Analysis of the association between dental disease existing before radiotherapy and the subsequent occurrence of osteoradionecrosis suggests that the incidence of necrosis is significantly greater in patients with dental disease (p = 0.09). The categorization of these patients relied on the subjective assessment of a single radiograph, which has recognized diagnostic inadequacies. The use of clinical assessment and more specific radiographs at the initial examination would be beneficial for accurate diagnosis of dental disease and might produce a higher level of association. However, this panoramic radiographic review does provide evidence of a statistically significant relationship between dental disease and osteoradionecrosis. Examination of the sensitivity of this relationship (47.6 percent) demonstrates that it is impossible to predict reliably which patients with dental disease will develop bone necrosis. In contrast, the specificity (76.0 percent) of the association indicates that when a patient is dentally healthy, there is a relatively low risk of osteoradionecrosis. Because of the complex etiology of osteoradionecrosis, a substantially higher level of association could not
Fig. 7. Case 2. Intraoral view demonstrating large area of necrotic mandible. A polystyrene guard had been worn over the upper teeth.
Fig. 8. Case 2. External draining sinus below the right
mandible.
104 Murray, Daly, and Zimmerman
Oral Surg. February, I980
be anticipated. For example, a certain percentage of patients will spontaneouslydevelop radiation necrosis of the mandible following irradiation, despite the absenceof teeth; diseasein thesecasesmust obviously be attributed to nondental factors.5 The exacerbationof existing dental diseasefollowing radiation therapy for malignant oral lesions is illustrated by the cases reported. Once radiation has been given,
diseased teeth cannot be extracted without
high-risk of bone necrosis. Therefore, in irradiated persons, dental diseasemust be treatedconservatively, and this may result in frequent episodes of infection and associated debilitating symptoms. Protracted conservative treatment can often be avoided by judicious case
selection and careful diagnosis, culminating in the elimination of dental disease prior to irradiation. The
extraction of teeth before radiation therapy does not appearto increasethe incidence of osteoradionecrosis.5 It is particularly important that dental diseasebe eliminated in patients with a history of dental neglect and poor oral hygiene and in persons who persist in smoking or drinking alcohol. These persons all exhibit an increased susceptibility to necrosis of the mandible,
and their necrotic diseasetends to be more prolonged and destructive. REFERENCES 1. Moss, W. T.: Therapeutic Radiology. ed. 2, St. Louis. 1965.The C. V. Mosby Company, p. 441. 2. Bragg, D., Homoyoan, S., Chu, F., and Higinbotham, N.: Clinical and Radiographic Aspects of Radiation Osteitis, Radiology 97: 103-107, 1970. 3. Gowgiel, J. M.: Experimental Radioosteonecrosisof the Jaws, J. Dent. Bes. 39: 176-197, 1960. 4. Hayward, J. R., Kerr, D. A., Jesse, R. H., Castighiano, S. G., Lampe, I., and Ingle, J. I.: The Managementof Teeth Related to the Treatment of Oral Cancer. in Oral Care for Oral Cancer Patient, Public Health Service Publication No. 1958, Washington, D. C. 1968, U. S. Departmentof Health, Educationand Welfare, pp. 1-8. 5. Murray, C. G.: The Incidence and Management of Osteoradionecrosisof the Mandible: A 10 Year Study. ResearchReport, The University of Texas Dental Branch and M. D. Anderson Hospital and Tumor Institute, May, 1979. Reprint requests to:
Dr. Christopher G. Murray 10th Floor, Coates Building 20 Collins St. Melbourne, 3000, Australia
INFORMATION FOR AUTHORS Most of the provisions of the Copyright Act of 1976 becameeffective on January I, 1978. Therefore, all manuscriptsmust be accompaniedby the following written statement,signed by one author: “The undersigned author transfersall copyright ownership of the manuscript entitled (title of article) to The C. V. Mosby Company in the event the work is published. The undersigned author warrants that the article is original, is not under consideration by anotherjournal, and has not been previously published. I sign for and accept responsibility for releasing this material on behalf of any and all co-authors.” Authors will be consulted, when possible, regarding republication of their material.
49, Number
2, February,
1980
oral surgery Editor: ROBERT B. SHIRA, D.D.S. School of Dental Medicine, Tufts University 1 Kneeland Street Boston Massachusetts 02 111
The relationship between dental disease and radiation necrosis of the mandible Christopher G. Murray, M.D.,%., MSc., F.R.A.C.D.S.,* Stuart 0. Zimmerman, Ph.D.,*** Houston, Texas UNIVERSITY INSTITUTE,
OF TEXAS AND
SYSTEM
UNIVERSITY
CANCER
CENTER,
M.
OF TEXAS
HEALTH
SCIENCE
Thomas E. Daly, D.D.S.,**
D. ANDERSON CENTER,
HOSPITAL
AND
DENTAL
BRANCH
and
TUMOR
Preirradiation panoramic radiographs of forty-six dentate patients were examined for the presence of significant dental disease. The occurrence of necrosis of the mandible after these patients received radiation therapy was then determined. Evidence of a positive association between dental disease present before radiation therapy and subsequent necrosis of the mandible was found (p = 0.09), leading to a recommendation that significant disease be eradicated before irradiation of oral tissues. Two cases are reported to illustrate the complications that can arise in dentate patients following radiation to the oral cavity. Considerable suffering results from bone necrosis, which can be reduced by careful and rational dental diagnosis and treatment
0
steoradionecrosis may occur after radiation damage to the cells of the bone and its vascular components. It is not known which cellular element is primarily injured, but the end result, osteoporosis leading to radionecrosis, may be expected following aggressive radiation treatment of oral cancer. ’ This research was supported in part by Grant CA 11430 and Contract NOl-CN-75175. National Cancer Institute. *Resident, Maxillofacial Prosthetics, Department of Dental Oncology. Present address: 10th Floor, Coates Building, 20 Collins St., Melbourne, 3000, Australia. **Professor of Dental Oncology. Department of Dental Oncology. ***Professor. Department of Biomathematics. 0030-4220/80/020099+06$00.60/0
0
1980
l-be C. V. Mosby Co.
The role that dental disease plays in the occurrence of bone necrosis following irradiation is uncertain. Bragg and associates* stated that clinical radiation necrosis of the mandible was associated with open mucosal wounds in nearly all cases. Soft-tissue necrosis frequently precedes bone necrosis, and a break in the integrity of the gingival tissues can also provide an entrance by which infection can reach the bone.3 Dental disease is the usual cause of disruption of the gingival crevicular tissues. Periodontal disease, dental abcesses, extensive dental caries, and impacted teeth may all provide a pathway for infection to reach mandibular bone whose reparative capacity has been im99
100
Murray, Daly, and Zimmerman
Oral Surg. February, 1980
Fig. 1. Case 1. Preirradiation panoramic radiograph.
Fig. 2. Case 1. Panoramic radiograph taken 18 months after irradiation showing rampant radiation caries, advancedperiodontal disease,and bone necrosis.
paired by the effects of irradiation.d The presence of microorganisms associated with these dental diseases in the irradiated field increases the probability of the compromised bones being infected. Dental disease situated beyond the actual field of radiation may also provide a focus of infection. Patients with teeth have more than twice as great a chance of developing necrosis as patients who are edentulous. This difference, which has been reported as significant at the p = 0.001 level,j suggests that a further decrease in the incidence of necrosis may be obtained by paying closer attention to the role that dental elements play in the necrotic process. With the radiotherapeutic techniques currently favored at M. D. Anderson Hospital and Tumor Institute, it appears that an over-all base rate of necrosis of about 12 percent can be predicted for edentulous patients. It is hoped that careful consideration of the role that teeth play in the occurrence of mandibular necrosis will permit the incidence of necrosis to be reduced from the reported 24.2
percent to a level closer to that found in edentulous patients. A natural den&ion is clearly beneficial for the irradiated cancer patient, but the potential hazards of retaining the dentition should not outweigh the advantages. This report describes a radiographic survey designed to determine the association between dental disease existing before irradiation and subsequent mandibular radiation necrosis. Two cases in which dental disease appeared to influence the pathogenesis of necrotic disease are also reported. MATERIALS
AND METHODS
From July, 1971, to December, 1975, 104 patients with malignant neoplasms of the floor of the mouth and retromolar trigone received initial treatment at M. D. Anderson Hospital and Tumor Institute, primarily with radiation. These tumor sites were selected for their proximity to the dentition so that any association between dental status and development of osteoradio-
Relationship between dental disease and radiation necrosis
Volume49
101
Number 2
Fig. 3. Case I. Panoramic
radiograph
taken 36 months
after irradiaton
showing pathologic right mandibular
fracture. Table I. Association between dental diseaseand radiation necrosis of the mandible in forty-six
patients irradiated for malignant tumors of floor of mourb and retromolar trigone Radiation necrosis +
Dentaldisease
+ -
IO 6 16
Total
II 19 30
21 25 46
0.09 p (10/16,1l/30) Sensitivity(tO/21)= 47.6% Spekificity(19/25)= 76.0%
necrosis would be apparent. Dentate persons were selected, and panoramic radiographs taken prior to radiation were examined. Forty-six radiographs were available for assessment. Hayward and co-authors” suggestedthat the decision to remove teeth before radiation therapy should be basedon the following criteria: (1) extensive caries, (2) moderate to advanced periodontal involvement, (3) lack of opposing teeth and consequentloss of function and self-cleansing action, (4) partial impaction or incomplete eruption, and (5) extensive periapical lesions. These factors were considered an acceptable basis for separatingthe preirradiation radiographs into those that revealed one or more of thesecriteria and thosethat did not. It was postulated that if a positive correlation existed between dental disease and osteoradionecrosis, this first
group of patients would be at risk by virtue of their dental status. The forty-six films were grouped without prior knowledge of subsequentnecrotic episodes, and the results were examined to determine the association
Fig. 4. Case 1. Intraoral view demonstratinglimited mandibular opening, intraoral hemorrhage, and poor dental status.
between dental pathosis and necrosis of the mandible occurring after radiation therapy. RESULTS Table I indicates the association between significant dental disease and mandibular radiation necrosis. From Table I the following statistical data were derived: p (dental disease/no dental disease) = 0.09 Sensitivity = 41.6% Specificity = 76.0%
Two cases illustrate the association between dental disease and osteoradionecrosis. CASE REPORTS Case 1
A 59-year-old Caucasian man was seen with a squamouscell carcinoma, stage T,N,, located in the right base of the tongue.
102
Murray, Daly, and Zimmerman
Oral Sure. February,198’0
Fig. 5. Case 2. Panoramic radiograph taken before the preirradiation removal of all lower teeth Dantal status
This patient had a history of dental neglect and poor oral hygiene. Alveolar bone loss was apparentaround most teeth, associatedwith chronic periodontal disease.Painless, draining peri’apical abscesseswere present on 41 and dental caries was present in 81678 (Fig. 1). It was decided that the existing dental situation did not warrant delaying radiation treatment. Oral prophylaxis and oral hygiene instruction were administered. A tongue and cheekguard was provided to protect the soft tissues from rubbing against the dentition, and 1 percent sodium fluoride was prescribed for daily application to the dentition via vacuum-formed polystyrene carriers. Fbdiation therapy
The tumor dose was 6,500 rads. The first 5,000 rads were delivered by photons from a cobalt-60 source using parallel opposedfields and a 2: 1 loading to the right side. A further 1,500 rads were given by an interstitial implant of radium needles 2 months after initiation of the external beam treatment. Postimadiation
progress
Six months after initiation of radiotherapy, the patient reported that he was not using fluoride regularly and his oral hygiene was poor. Despite further instruction, the oral situation at 12 months had deteriorated, and by the end of 18 months rampant radiation caries and bone necrosiswere present (Fig. 2). An asymptomatic 2 by 1 cm. area of bone was exposed on the lingual aspect of the right mandible in the molar region. Systemic antibiotics and neomycin mouth rinses were prescribed, and oral hygiene instruction was given. By the end of 22 months a purulent dischargewas draining from the gingival sulci of many teeth, particularly in the lower right molar region. The lower right secondmolar was extremely mobile but asymptomatic. Necrotic bone was removed from the right mandible and the patient was further counseled regarding oral hygiene. By 24 months the lower tight second molar had been sequestrated.Ten months later the fluoride treatments had been discontinued and radiation
decay was progressing.Extensive bone necrosisof both cortical plates of the right mandible was evident. The patient was unresponsive to advice. At 36 months mandibular fracture occurred through the lower right second molar region, accompanied by hemorrhage. A large hematomawas present in the tissues of the right cheek, and trismus of the massetermuscle restricted mandibular opening (Figs. 3 and 4). Five days after the initial hemorrhagic episode, the patient underwent a tracheostomy, resection of the right mandible, and ligation of the external maxillary artery. Case 2
A Caucasian woman was 55 years of age at the time of presentation with a squamous-cell carcinoma, stage TaN,, located in the oral tongue. Dantal status
This patient had sought dental treatmentat irregular intervals, and her oral hygiene was describedat the initial examination as “fair. ” Periodontal diseaseinvolved the remaining dentition, particularly the lower anterior teeth (Fig. 5). Before commencing irradiation, we decided to extract all teeth in the lower dental arch and the upper incisors, which were pariapitally involved. The remaining teeth were managed in the samemanner as described for Case 1. Radiation therapy
The tumor dose was 6,000 rads. The first 5,000 rads were delivered by photons from a cobalt-60 source using parallel opposedfields. An additional 1,000 rads were given by a 7 MeV electron beam. The treatment time was 2 months. Postirradiation
progress
Nine months after the start of radiation treatment, the patient complained of pain in the upper left second premolar. Advanced periodontal diseasewas presentaround the remaining teeth, and the premolar pain was attributed to that. Oral hygiene was poor and there was inflammation of the lower right alveolus where the upper right molars contracted. The patient was further instructed in oral hygiene proceduresand a
Volume49 Number2
Relationship betweendental disease and radiation necrosis 103
Fig. 6. Case2. Panoramicradiograph taken 27 months after irradiation showing mandibular necrosis at the site of contact of the unopposed upper right molars.
polystyrene mouth guard was fabricated to reduce trauma to the edentulous right mandible. At 22 months, exposed necrotic bone was evident on the right mandible where the polystyrene mouth guard on the upper teeth madecontact. Antibiotics were prescribed. By 27 months a larger area of necrotic bone was visible, and pus was draining externally via a sinus below the right mandible
(Figs. 6, 7, and 8). The area was irrigated, oral hygiene instruction was given, and a further course of antibiotics was prescribed. The final outcomeof the progressivenecrotic disease in this patient is not known. DISCUSSION
Analysis of the association between dental disease existing before radiotherapy and the subsequent occurrence of osteoradionecrosis suggests that the incidence of necrosis is significantly greater in patients with dental disease (p = 0.09). The categorization of these patients relied on the subjective assessment of a single radiograph, which has recognized diagnostic inadequacies. The use of clinical assessment and more specific radiographs at the initial examination would be beneficial for accurate diagnosis of dental disease and might produce a higher level of association. However, this panoramic radiographic review does provide evidence of a statistically significant relationship between dental disease and osteoradionecrosis. Examination of the sensitivity of this relationship (47.6 percent) demonstrates that it is impossible to predict reliably which patients with dental disease will develop bone necrosis. In contrast, the specificity (76.0 percent) of the association indicates that when a patient is dentally healthy, there is a relatively low risk of osteoradionecrosis. Because of the complex etiology of osteoradionecrosis, a substantially higher level of association could not
Fig. 7. Case 2. Intraoral view demonstrating large area of necrotic mandible. A polystyrene guard had been worn over the upper teeth.
Fig. 8. Case 2. External draining sinus below the right
mandible.
104 Murray, Daly, and Zimmerman
Oral Surg. February, I980
be anticipated. For example, a certain percentage of patients will spontaneouslydevelop radiation necrosis of the mandible following irradiation, despite the absenceof teeth; diseasein thesecasesmust obviously be attributed to nondental factors.5 The exacerbationof existing dental diseasefollowing radiation therapy for malignant oral lesions is illustrated by the cases reported. Once radiation has been given,
diseased teeth cannot be extracted without
high-risk of bone necrosis. Therefore, in irradiated persons, dental diseasemust be treatedconservatively, and this may result in frequent episodes of infection and associated debilitating symptoms. Protracted conservative treatment can often be avoided by judicious case
selection and careful diagnosis, culminating in the elimination of dental disease prior to irradiation. The
extraction of teeth before radiation therapy does not appearto increasethe incidence of osteoradionecrosis.5 It is particularly important that dental diseasebe eliminated in patients with a history of dental neglect and poor oral hygiene and in persons who persist in smoking or drinking alcohol. These persons all exhibit an increased susceptibility to necrosis of the mandible,
and their necrotic diseasetends to be more prolonged and destructive. REFERENCES 1. Moss, W. T.: Therapeutic Radiology. ed. 2, St. Louis. 1965.The C. V. Mosby Company, p. 441. 2. Bragg, D., Homoyoan, S., Chu, F., and Higinbotham, N.: Clinical and Radiographic Aspects of Radiation Osteitis, Radiology 97: 103-107, 1970. 3. Gowgiel, J. M.: Experimental Radioosteonecrosisof the Jaws, J. Dent. Bes. 39: 176-197, 1960. 4. Hayward, J. R., Kerr, D. A., Jesse, R. H., Castighiano, S. G., Lampe, I., and Ingle, J. I.: The Managementof Teeth Related to the Treatment of Oral Cancer. in Oral Care for Oral Cancer Patient, Public Health Service Publication No. 1958, Washington, D. C. 1968, U. S. Departmentof Health, Educationand Welfare, pp. 1-8. 5. Murray, C. G.: The Incidence and Management of Osteoradionecrosisof the Mandible: A 10 Year Study. ResearchReport, The University of Texas Dental Branch and M. D. Anderson Hospital and Tumor Institute, May, 1979. Reprint requests to:
Dr. Christopher G. Murray 10th Floor, Coates Building 20 Collins St. Melbourne, 3000, Australia
INFORMATION FOR AUTHORS Most of the provisions of the Copyright Act of 1976 becameeffective on January I, 1978. Therefore, all manuscriptsmust be accompaniedby the following written statement,signed by one author: “The undersigned author transfersall copyright ownership of the manuscript entitled (title of article) to The C. V. Mosby Company in the event the work is published. The undersigned author warrants that the article is original, is not under consideration by anotherjournal, and has not been previously published. I sign for and accept responsibility for releasing this material on behalf of any and all co-authors.” Authors will be consulted, when possible, regarding republication of their material.