Rehabilitation of oral function in head and neck cancer patients after radiotherapy with implant-retained dentures: Effects of hyperbaric oxygen therapy

Summary

Surgical treatment of malignancies in the oral cavity and subsequent radiotherapy often result in an anatomic and physiological oral condition unfavorable for prosthodontic rehabilitation. The objective of this prospective study was to assess the effect of hyperbaric oxygen therapy on treatment outcome (condition of peri-implant tissues, implant survival, oral functioning and quality of life) of prosthodontic rehabilitation with implant-retained lower dentures in radiated head and neck cancer patients 6 weeks and 1 year after placing the new dentures. The treatment outcome was assessed in a group of 26 head neck cancer patients who were subjected to radiotherapy after tumour surgery. Standardized questionnaires were completed and clinical and radiographic assessments were performed. After randomization, endosseous Brånemark implants were placed in the anterior part of the mandible either under antibiotic prophylaxis (13 patients) or under antibiotic prophylaxis combined with pre and postsurgery hyperbaric oxygen (HBO) treatment (13 patients). In the HBO and non-HBO group eight implants (implant survival 85.2%) and three implants (implant survival 93.9%) were lost, respectively. Peri-implant tissues had a healthy appearance in both groups. Osteoradionecrosis developed in one patient in the HBO group. All patients functioned well with their implant-retained lower denture. The quality of life related to oral functioning and denture satisfaction were improved to a comparable extent in the HBO and non-HBO group.

Implant-retained lower dentures can improve the quality of life related to oral functioning and denture satisfaction in head and neck cancer patients. Adjuvant hyperbaric oxygen therapy could not be shown to enhance implant survival in radiated mandibular jaw bone.

Introduction

Surgical treatment of malignancies involving the oral cavity often results in an altered anatomical situation, which may severely hamper oral functioning. Surgical treatment is often combined with radiotherapy, which further worsens oral functioning. Salivary secretion is reduced, and speech, chewing (mastication), swallowing and aesthetics are often impaired.1, 2, 3, 4, 5, 6, 7, 8 Due to the changed intra-oral conditions (changed anatomy, oral sequelae of radiotherapy) the possibilities to obtain proper stability and retention for a mandibular prosthesis are seriously at risk.1, 9, 10, 11 For example, particularly after radiotherapy, the load-bearing capacity of both the native and reconstructed tissues is compromised.5, 9, 12, 13 Until recently neither reconstructive surgery nor conventional prosthodontic techniques were capable to address these problems successfully.14, 15 In prospective studies with a follow-up of 10 years reporting on the treatment outcome of implant-retained overdentures in healthy patients suffering from impaired oral functioning due to an unstable lower denture, implant-retained overdentures have been proven to be a reliable treatment for problems involving lack of stability and retention of a lower denture.¹⁶ Because of this high success rate a similar prosthodontic treatment approach can probably attribute to better functional results in the oral rehabilitation of head and neck cancer patients.4, 8, 9, 11, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26

Nowadays, endosseous implants are used with increasing frequency for prosthetic support in patients who are treated for malignancies in the lower region of the oral cavity.10, 12, 20, 26, 27 Such implant-based prosthodontic rehabilitation is not only performed in patients in whom the mandible and soft tissues were reconstructed, but also in patients in whom the mandible was located in the radiation portals, in spite of the well-documented adverse biologic changes that occur when soft and osseous tissues have been exposed to ionizing radiation.5, 6, 7, 20, 28, 29, 30, 31 It has been stated that implant surgery at irradiated sites bears the significant risk of development of soft and hard tissue necrosis, and loss of implants.³² Moreover, the appropriateness of using implants in irradiated patients has been seriously questioned.¹⁸ To reduce these risks, the need for adjunctive prophylaxis with long lasting use of antibiotics and hyperbaric oxygen (HBO) therapy has been proposed.³³

It was advocated to use HBO therapy prior to implant placement to improve blood flow in compromised areas. Experimental data reporting increased bone mineralization and increased biomechanical forces needed to unscrew titanium implants after HBO therapy have given support to this assumption.34, 35 Nevertheless, there is still no consensus or sound evidence in the literature concerning the benefit of HBO to improve osseointegration of dental implants in mandibles, to reduce loss of implants and to minimise risk of development of osteoradionecrosis in patients who have been treated with radiotherapy following cancer treatment.³⁶ Currently, the need for more detailed outcome research has brought up the issue of measuring the quality of life of cancer patients by assessing their functional status as well as their physical, social and emotional well-being through self-administered questionnaires.³⁷

Therefore, the objective of this prospective study was to assess the effect of HBO therapy on treatment outcome (condition of peri-implant tissues, implant survival, oral functioning and quality of life) of prosthodontic rehabilitation with implant-retained lower dentures in irradiated head neck cancer patients.