Implant Overdentures Versus Conventional Dentures
People who have lost all of their teeth suffer from a chronic condition. By definition, all treatment of a chronic condition is palliative, as there cannot be a restitutio ad integrum. Consequently, a patient has to live with all impacts on his or herwell-being, those stemming from both the disease and the therapy. In the case of complete edentulism, impacts of disease are the obvious disfigurement, impaired speech, and problems with biting and chewing.
Traditional prosthetic rehabilitation of edentulous patients focuses on the replacement of structure with removable prostheses. However, the “therapeutic” effect may not be complete; although improved, function still may be impaired with clinically acceptable dentures.
Traditionally, the condition of an edentulous patient has been measured in clinical terms, such as ridge height and profile or the position and quality of the mucosa.1-3 The clinical success of complete denture treatment has been measured using bite force4 and functional tests of chewing capacity and efficiency.5,6 However, correlations between clinical measures and the condition reported by the patient are often poor and nonsignificant (Table 5-1). These poor correlations between clinical factors and patient assessments emphasize that while prosthetic therapy in the past has focused on restoring lost structure, function, and esthetics, the edentulous condition affects patients on a personal level. Research only recently has shifted toward surveying edentulous patients regarding their priorities for complete denture treatment. For patients, the most important qualities of complete dentures are comfort, stability, and ability to chew with the denture. Other factors include esthetics, ability to speak, and ease of cleaning the denture.7,8
Satisfaction as an outcome measure has experienced a renaissance in the past 10 years. Satisfaction describes the patient’s valuation of a specific aspect of (denture) treatment. As with most patient outcomes, satisfaction is measured using self-administered questionnaires. Categories of measurement include general satisfaction, satisfaction with stability, comfort, esthetics, speech, chewing ability, and ease of cleaning. For scaling purposes, questions are either coupled with multi-step an-swer categories (Likert scales) or visual analog scales (VAS; Fig 5-1).
Dissatisfaction with complete denture treatment among edentulous patients has been an issue for many years. For instance, a survey of elderly patients showed 66% were dissatisfied with their complete dentures.The main reasons for dissatisfaction were discomfort, poor fit and retention, and especially soreness and pain under mandibular dentures, which can cause many more problems than maxillary dentures.3,9
It has been shown that the satisfaction with conventional dentures and implant overdentures depends on patients’ ability to chew and speak and on the appearance of the prostheses.1,10,11 Carlsson et al1 proposed that self-ratings of retention and the sense of security with the denture also contribute to patient satisfaction with complete dentures.
Several studies have compared simple mandibular overdentures supported by two implants to conventional complete dentures using a questionnaire approach. However, few studies are randomized controlled trials; only these will be reviewed here.
Researchers from the Netherlands conducted a randomized multicenter study (90 patients) to compare patient satisfaction with mandibular conventional dentures (n = 30), with conventional dentures combined with surgical vestibuloplasty (n = 30), and with over-dentures supported by two implants (n = 30). A validated questionnaire (test-retest reliability r = 0.8 to 0.9) targeted patient satisfaction with esthetics, retention, functional comfort, and the ability to eat and speak with the dentures, all rated on 5-point scales. General satisfaction was rated on a 10-point scale. One year posttreatment, general satisfaction with implant overdentures and conventional dentures combined with vestibuloplasty was significantly higher than with conventional dentures alone. No significance tests were reported for the other parameters.12,13 Five years posttreatment, the positive effect of vestibuloplasty had disappeared and the difference with conventional treatment alone was no longer significant. However, implant overdentures consistently produced significantly higher general satisfaction scores compared to both alternative treatments.14
Similar results were reported by Geertman et al.15,16 In a randomized trial of 151 patients, 60 received conventional complete dentures. Ninety-one patients had three different types of implants (transmandibular, hollow cylinder, and screw type) placed and were finally restored with mandibular implant overdentures retained by a bar-clip. Patients with implant overdentures had higher general satisfaction ratings than patients with conventional dentures. No statistical comparisons were reported. 15,16
In a randomized trial by Kapur et al,17 new maxillary and mandibular dentures were delivered to diabetic denture patients who treated their diabetes either with or without insulin. Of 89 patients, 37 received maxillary and mandibular conventional dentures and 52 received a maxillary conventional denture and a mandibular implant overdenture. Questionnaires with categorical responses were used to ascertain patients’ absolute assessments of original dentures at baseline and study dentures at 6 and 24 months after completion of treatment. While longitudinal data for the satisfaction questionnaire showed improvements with both types of study dentures, improvements were higher in the implant overdenture group than in the conventional denture group. Statistical evaluation of percentage distributions for the evaluation of the study dentures showed significant improvements in the implant overdenture group for eating enjoyment and general satisfaction. A significant between-group difference was detected for speech in favor of the implant overdenture group. Mean scores failed to show any significant differences between the two treatment groups. With the comparative questionnaire, a higher percentage of patients in the implant overdenture group than in the conventional denture group perceived improvements with study dentures from their original dentures in chewing ability, chewing comfort, and denture security.17