Biomedical subjects

M A Van Waas

Publications and source records attributed to M A Van Waas.

9 recordsLinked to original sources

PubMed1998

Randomized prospective clinical trial of two implant systems for overdenture treatment: a comparison of the 2-year and 5-year results using the clinical implant performance scale.

In a prospective randomized clinical trial, edentulous patients were treated with dental implants and overdentures. The results of treatment with two IMZ implants connected by a Dolderbar, and a transmandibular implant (TMI) were compared. By using the clinical implant performance scale, the clinical and radiographic data were evaluated and compared after a two-year and five-year follow up. After the five-year follow up, significantly less problems and complications were recorded in the IMZ group than in the TMI group (Wilcoxon, P=0.03). When compared to the two-year follow up, there was, however, a gradual increase of scores on the clinical implant performance scale in the IMZ group, while in the TMI group only a slight increase was recorded.

Adult↗

PubMed1997

Construction of a clinical implant performance scale for implant systems with overdentures with the Delphi method.

STATEMENT OF PROBLEM: The success of an implant system is often judged on the survival rate of the separate implants. This does not give a complete view of the "real" success of a system. To make that possible the total clinical performance, surgical and prosthetic, has to be considered. PURPOSE: This study aimed to set up a clinical performance scale for different implant systems retaining mandibular overdentures. MATERIAL AND METHODS: All data regarding surgical and prosthetic complications incurred and treatment procedures needed after implant placement were collected from a group of 90 patients who were treated either with two root form implants connected with a bar and supporting a mandibular overdenture or with a transmandibular implant system that supported an overdenture. All items were scored into five categories on the scale, defined as the "clinical implant performance" scale. The Delphi method was applied to categorize each item. A panel of experts assessed the items. RESULTS: After three rounds there was complete consensus between the experts for 65% of the items for the root form implant systems, and for 87% of the items at least five out of six experts gave the same score. For 55% of the items for the transmandibular implants systems there was complete consensus, and for 85% of the items at least five out of six experts scored in the same way. CONCLUSIONS: The Delphi method provides a useful scale for evaluating the clinical performance of implant systems retaining mandibular overdentures. The presented scale makes it possible to compare the overall performance of different implant systems for overdentures.

Delphi Technique↗

PubMed1997

Bone level changes in patients with transmandibular implants.

PURPOSE: In this article, the mandibular bone height in edentulous patients previously treated with a transmandibular implant was evaluated after the dentures were modified according to the latest prosthetic protocol. PATIENTS AND METHODS: The bone height of 36 patients was measured on three radiographs; the first at the time of insertion of the implant, the second just before using the latest prosthetic protocol, and the third 1 year later. RESULTS: A slight bone increase at the lateral posts and at the cortical screws mesial to these posts was measured. No significant bone increase was found above the lateral cortical screw. CONCLUSION: The bone increase that is found in this study was not of the extent indicated in earlier reports.

Adult↗

PubMed1997

Patient satisfaction with implant-supported mandibular overdentures. A comparison of three treatment strategies with ITI-dental implants.

In a randomized, controlled clinical trial, 110 edentulous patients with atrophic mandibles were treated with International Team for Oral Implantology-dental implants using three different treatment strategies: a mandibular overdenture supported by two implants with ball attachments, two implants with an interconnecting bar, or four interconnected implants. The patients' opinions and their social functioning were evaluated by means of a questionnaire directly before and 16 months after treatment. Before treatment most patients had complaints about the retention of their mandibular denture. Sixteen months after treatment almost all patients were generally satisfied with their dentures. Since no significant difference was found between the three treatment strategies, it was concluded that simple implant treatment such as an overdenture retained by two ball attachments is sufficient.

Analysis of Variance↗

PubMed1996

Clinical aspects of a multicenter clinical trial of implant-retained mandibular overdentures in patients with severely resorbed mandibles.

In a multicenter clinical trial treatment, the effects of overdentures on different implant systems in patients with severely resorbed mandibles were compared 1 year after the insertion of new dentures. The implant systems used were the transmandibular implant (TMI), the IMZ (IMZ), and the Brånemark system (BRA). Treatment was randomly assigned to 88 patients according to a balanced allocation method. Evaluation included peri-implant and radiographic parameters. According to the Delphi method a Clinical Implant Performance scale (CIP) was constructed based on all conceivable complications of the different implant systems. During the healing period, one IMZ and one BRA implant were lost, and one TMI implant was removed after functional loading. The results of the peri-implant and radiographic parameters and the CIP scale revealed no significant differences between the three implant systems.

Adult↗

PubMed1996

Two-center clinical trial of implant-retained mandibular overdentures versus complete dentures-chewing ability.

This study is a two-center clinical trial with the aim to assess the treatment effects of implant-retained mandibular overdentures versus conventional complete dentures. Treatment had been assigned according to a balanced allocation method. The following criteria were used to enhance the comparability of the treatment groups: age, gender, the edentulous period of the mandible, the number of previously made mandibular dentures, the number of years having worn the present mandibular denture and the symphyseal bone height. 151 patients with severely resorbed mandibles participated in the study, they were treated at two centers. Ninety-one patients received an implant-retained mandibular overdenture (IRO) and 60 patients a conventional complete denture (CD). Since some patients refused the allocated treatment the "Intention To Treat" principle was applied. This implies that patients are evaluated in the originally allocated treatment group regardless of the actual treatment they received. Patient's experiences were evaluated before treatment and 1 yr after insertion of the new dentures. Results before treatment showed that both treatment groups were comparable: they were dissatisfied with their mandibular denture and they could hardly chew tough or hard foods. One year after insertion of the new dentures the IRO-group was satisfied with their mandibular denture, whereas only one third of the CD-group was satisfied. With respect to the chewing ability the IRO-group scored significantly better than the CD-group(P<0.0001).

Adult↗

PubMed1995

Satisfaction with complete immediate dentures and complete immediate overdentures. A 1 year survey.

The aim of this study was to evaluate denture satisfaction over a 1 year period after extraction of the last teeth. Seventy-four patients who required immediate denture therapy in the mandible were randomly treated, (1) with complete immediate dentures (22); (2) with immediate overdentures on two lower canines without attachments (26); or (3) with immediate overdentures on two lower canines provided with Dyna direct magnetic attachments, inserted on the abutments 9 months after treatment (26). Denture satisfaction was estimated by means of questionnaires, filled out by each patient at certain periods, starting before treatment and ending 1 year after denture insertion. After 1 year approximately 85% of the patients in the three groups were satisfied with their dentures, had got used to them and could eat well. This phenomenon was constant over the whole first year period. No differences in denture satisfaction were found between the three groups. It can be concluded that although patients who receive immediate complete dentures might experience a lot of discomfort during the first year of edentulousness, they are satisfied, in general, with their dentures independent of the treatment procedure.

Adaptation, Psychological↗

PubMed1993

Oral function in dentate elderly with reduced dentitions.

This study covers the characteristics of reduced dentitions in a population of elderly people. The sample consisted of 329 independently living individuals between 55 and 75 years of age. They all had one or more natural teeth and were all interviewed and investigated clinically. The findings showed that 13% of the subjects had a natural dentition with at least the first molars; 4-7 natural occlusal units (defined as 'pairs of opposing teeth that support the occlusion') occurred in 37% of the subjects; 1-4 natural occlusal units in 41% and 0 units in 9% (only anterior contacts). A removable partial denture was worn by 39% of the subjects; most of them were acrylic based dentures (61%). The percentages of restored teeth per subject were high. The need for further restorations, however, was low. Periodontal problems were uncommon; 25% of the subjects had one pocket above 5 mm; 8% had severe problems. Poor oral hygiene was present in a quarter of the cases. Most of the subjects (70%) had no pain or noises in the temporomandibular joint. Only 10% of subjects had more than one sign of craniomandibular dysfunction. Most of the subjects (85%) visit their dentist regularly and 65% had their last tooth extraction more than three years ago. A majority mentioned that they have never had problems with their dentition in the past; 50% had had no real toothache for the last five years. However, problems with food-packing were often mentioned. It can be concluded that, although the dentitions of the elderly in this population are often reduced, their dentitions are in general in good condition and few give TMJ problems.

Aged↗

PubMed1993

Differences two years after tooth extraction in mandibular bone reduction in patients treated with immediate overdentures or with immediate complete dentures.

In a randomized controlled clinical trial, 74 patients who required immediate dentures were randomly treated with immediate overdentures on two lower canines or with immediate complete dentures. Mandibular bone reduction was measured by use of oblique lateral cephalometric radiographs made at baseline and the results compared with those of one year and two years after denture treatment. Analysis of the data showed that the average bone reduction in the lower canine regions in the first year was 0.9 mm in the immediate-overdenture group and 1.8 mm in the immediate complete-denture group. In the posterior parts of the mandible, the bone reductions were, respectively, 0.7 mm and 1.9 mm. The differences were statistically significant in all measured regions. During the second year, no significant differences in bone reduction were found. The sums of differences in the first two years were significant in all regions except the molar region, preserving the initial difference. Retention of roots of canines beneath a mandibular denture in immediate denture patients, even when they were in poor condition, reduced the collapse of the alveolar processes in all regions of the mandible.

Alveolar Bone Loss↗