Implant Prosthetic Rehabilitation of an Edentulous Irradiated Maxillary Defect

Robert F. Wright, DDS* ; Steven M. Roser, DMD, MD**

ABSTRACT
Case report of a head and neck cancer patient who was unable to wear a conventional removable obturation. Maxillary and mandibular implants were placed, and clip bars were used to provide retention and stability for an esthetically pleasing and comfortable prosthesis. (Col Dent Rev 2:41, 1997)

INTRODUCTION

The difficulty of rehabilitation of edentulous maxillary defects has been discussed in the literature by Desjardins.3 Kabcanell et al and Block reported on the use of endosseous implants to increase retention for maxillary obturators.2,3 Many maxillectomy patients are also treated with adjuvant radiation therapy. It has been known for years that irradiated bone has been compromised due to damage to the osteoprogenitor cells4 and due to reduced vascularity.5 Jacobsson and others have shown normal recovery of bone formation after one year in irradiated rabbit bone.6 This study has been confirmed by King and others.9 Most of the literature reports on the placement of implants in irradiated extraoral tissue. Jacobsson et al inserted 35 implants in previously irradiated sites in nine patients. He reported nearly 83% success rate and no osteoradionecrosis was found.7 Wolfaardt reported an overall success rate of 69.4% for extra-oral implants in irradiated facial bone compared to 97.5% in irradiated facial bone.12,14

Reports are limited to implants in irradiated jaws. Albrektsson11 reported 21 mandibular and ten maxillary implants in previously irradiated jaws with no loss of implant at 1 to 5 years. Taylor13 reported 21 Branemark fixtures placed in previously irradiated

mandibles in four patients. The implants have been functioning for 3-7 years without any complications and without any implants lost. Three patients in this study had hyperbaric oxygen (HBO) treatment. Marx has described significant results when HBO-treated surgical patients were compared with non-treated controls.10,11

CASE REPORT

In January 1990, this 62 year old patient had a right maxillectomy and a right orbital exenteration for squamous cell carcinoma. He was treated post-operatively with 50G of radiation therapy. He presented wearing a poorly retained maxillary obturator and a poorly retained mandibular complete denture. Both prostheses were lined with a temporary reline material. The patient was totally edentulous and had severe atrophy of the maxillary and mandibular residual alveolar ridges. The patient wore a patch over the orbital defect and preferred this over an orbital prosthesis. The patient was treatment planned for a maxillary clip bar retained obturator and a mandibular implant retained overdenture.

A panoramic radiograph and maxillary and mandibular CT scans were used to prepare the surgical stent. Stage I was in March 1991 (Figure 1). Two 7mm and two 10mm fixtures were placed in the maxilla and four 13mm fixtures were place in the mandible. Stage II was performed in October 1991. Angled abutments were placed on the maxillary fixtures to allow room for the clip bar so that the prosthetic teeth could be positioned within the neutral zone (Figure 2). Two Nobelpharma ball attachments were used on the posterior mandibular fixtures. Conventional abutment (5.5mm and 4.0mm) were place on the anterior fixtures for an anterior clip bar. The patient was restored with a maxillary implant retained obturator that utilized two clips and a gold bar. A mandibular overdenture was fabricated utilizing the anterior clip bar and the ball attachments (Nobelpharma). Zero degree prosthetic teeth were utilized to decrease lateral forces. Basic prosthodontic principles were followed; and both prostheses were very retentive and stable (Figure 3).

Figure 1: Post-surgical panoramic radiograph showing the
four maxillary and mandibular implants.

Figure 2: Maxillary defect being restored with four implants
into the left maxilla. A clip bar design was utilized for the
maxillary implant retained rator.

Figure 3: Prosthetic rehabilitation with a maxillary implant
retained obturator and mandibular implant overdenture.

DISCUSSION

This patient has had a definite improvement in the quality of his life. He can now speak and eat properly, and has a dramatic improvement in esthetics. This patient has been followed routinely for the past 6 years following implant prosthetic rehabilitation.

CONCLUSION

Implants can be utilized to enhance prosthetic rehabilitation in carefully selected patients who have undergone jaw resection and irradiation. However, we need more research on the use of implants in irradiated bone. Clinical trials are needed regarding the role of hyperbaric oxygen in previously irradiated patients.

REFERENCES

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