Overdentures on primary mandibular implants in patients with oral cancer: a follow-up study over 14 years

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Abstract

We aimed to assess oral functioning, patients’ satisfaction, condition of peri-implant tissues, and survival of implants up to 14 years after their insertion in patients with oral cancer who had had mandibular overdentures placed over primary implants. Endosseous dental implants were inserted prospectively in the interforaminal region of the mandible during resection of the tumour in 164/180 patients with oral cancer. All 58 patients were evaluated by questionnaires and clinical assessments during a final assessment in 2012. Implant-retained mandibular overdentures were inserted, and prosthetic rehabilitation and oral functioning were not associated with primary site or stage of the tumour, number or type of implants inserted, or the type of reconstruction. Over time the peri-implant mucosa was usually free of inflammation. More implants were lost in patients treated by radiotherapy (27/318, 8.5%) than in those not so treated (1/206, 0.5%). Patients who had been treated by irradiation reported more problems in oral functioning and less satisfaction than those who had not. Patients with an implant-retained mandibular overdenture reported fewer problems in oral functioning than patients without an overdenture.

Primary insertion of an implant should be routinely incorporated in the surgical planning for patients with oral cancer, as oral functioning in those wearing mandibular overdentures improved considerably and peri-implant health was at least reasonable.

Introduction

Resection of a tumour in the oral cavity can have a profound effect on oral functions such as chewing, swallowing, and intelligible speech.1 Postoperative radiotherapy usually further compromises oral functioning. Changes in oral anatomy as a result of resection, and complications of radiotherapy such as xerostomia and intolerance of the denture-bearing mucosa to mechanical loading, limit prosthetic rehabilitation in these patients.2 Prosthetic rehabilitation of edentulous patients after treatment of oral cancer is difficult and therefore often omitted. However, adequate prosthetic rehabilitation is a pivotal factor for patients to regain oral function.3

In healthy patients oral function can be improved using implant-retained mandibular overdentures,4, 5 and this treatment has become important in the rehabilitation of oral cancer patients as well.6 Implants may be best inserted at the time of the resection (primary insertion of implants),7, 8, 9, 10, 11 as many patients postpone or simply decline implant-based treatment if it is offered after resection of the tumour and postoperative radiotherapy.12, 13, 14

Primary insertion appreciably reduces time between resection and prosthetic rehabilitation. This may allow patients to regain better oral function sooner after completion of the oncological treatment. Another advantage is the presumed higher survival rate of the implants when they are inserted before instead of after radiotherapy, as initial osseointegration will have taken place before the implants and mandibular bone are exposed to ionising radiation. Systematic reviews have shown that most publications about dental implants in patients with oral cancer referred to implants inserted after resection, or radiotherapy, or both, had been completed.15, 16 Only a limited number of studies reported primary implants. We presume that the benefits of primary insertion outweigh the risk that the implants will not be used for prosthetic rehabilitation. However, further study is needed to estimate which patients with oral cancer can benefit from primary implants. Does it depend on the primary site of the tumour, its size, whether the patient is treated by radiotherapy, or the type of reconstruction?

In this study we have assessed the outcomes of treatment (which patients benefit, their quality of life, their oral functioning and satisfaction, the condition of the peri-implant tissues, and survival of the implant) in a prospective cohort of 164 patients with oral cancer who were given primary mandibular implants to support an implant-retained mandibular overdenture up to 14 years after insertion of the implants.

Section snippets

Inclusion criteria and treatment

All consecutive edentulous patients with oral cancer referred to the Head and Neck Oncology group of the University Medical Centre Groningen between May 1998 and November 2010 were screened to be included in this study. Inclusion criteria were: edentulous upper and lower jaw; history of prosthetic problems related to lack of stability and retention of the lower denture, or expected problems with the lower denture after oncological treatment; malignancy in the lower oral cavity or oropharynx

Patients and implants

One hundred and eighty patients fulfilled the inclusion criteria. Fifteen patients did not have implants inserted because of anatomical limitations in the mandible that appeared or were created during resection (such as lack of enough bone in which to insert the implant). One patient had chosen conventional treatment instead of insertion of an implant, so a total of 16 patients were excluded from analyses. Selection of patients is shown in Figure 1, and details of patients in Table 1.

Loss of

Discussion

Many edentulous patients with oral cancer may benefit from insertion of endosseous dental implants during resection of the tumour at an early stage. Completion of prosthetic rehabilitation and oral functioning, chewing ability, and patients’ satisfaction were independent of site or stage of tumour, type of reconstruction, and the number of implants inserted. Patients wearing an implant-retained mandibular overdenture were able to chew significantly better, were less awkward socially, and had

Conflict of Interest

None declared

Ethics statement/confirmation that permission of patients was given

None required

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