Biomedical subjects

R P Van Oort

Publications and source records attributed to R P Van Oort.

10 recordsLinked to original sources

PubMed2002

Five years of aftercare of implant-retained mandibular overdentures and conventional dentures.

The purpose of this multicentre randomized clinical trial was to analyse surgical and prosthetic aftercare and clinical implant performance of edentulous patients with implant-retained mandibular overdentures and of patients with conventional dentures, either or not after pre-prosthetic vestibuloplasty and deepening of the floor of the mouth. The evaluation period was 5 years. The implant systems evaluated were the IMZ implant system, the Brånemark implant system and the Transmandibular Implant system. The centre in Groningen had five groups (n=149) and the centre in Nijmegen had three groups (n=86). The evaluation comprised of surgical and prosthetic aftercare, together with clinical implant performance (CIP). The highest implant loss (29%) is found in the Transmandibular Implant group. All groups had prosthetic revisions and complications according to the CIP-scale. The majority of the patients in the endosseous implant groups were subject to minor complications. The CIP-score of the Transmandibular Implant group is significantly higher than the scores of the other groups, because of the high number of lost posts. In 26;1% of the patients in this group score 4 is given, which means failure of the implant system. From this study it can be concluded that the endosseous implant systems used in this study have less surgical aftercare and a better clinical implant performance than the Transmandibular Implant system and are therefore the systems of choice for the edentulous mandible.

Aftercare↗

PubMed2000

A controlled clinical trial of implant-retained mandibular overdentures; five-years' results of clinical aspects and aftercare of IMZ implants and Brånemark implants.

The aim of this prospective randomized controlled clinical trial was to evaluate a set of clinical items and prosthetic aftercare of edentulous patients with a mandibular overdenture retained by 2 IMZ implants or 2 Brånemark implants during a 5-years' period. Patients were allocated to the IMZ group (n = 29) or the Brånemark group (n = 32) by a computerized balancing method. In the IMZ group 4 implants were lost during the 5-years' follow-up (survival rate: 93%). In the Brånemark group 9 implants were lost (survival rate: 86%). All patients were re-operated successfully. Multiple prosthetic revisions were necessary in both groups, especially the precision attachment system in the overdenture was subject to frequent fracture or loosening. From this study can be concluded that there is no difference in clinical state, radiographical state, survival rate and clinical implant performance between the IMZ implant system and the Brånemark implant system supporting an overdenture on 2 implants after 5 years of follow-up.

Chi-Square Distribution↗

PubMed1999

Implant-retained mandibular overdentures compared with complete dentures; a 5-years' follow-up study of clinical aspects and patient satisfaction.

The aim of this prospective randomized controlled clinical trial was to evaluate and compare clinical aspects and satisfaction during the first year following treatment and consecutively the change in treatment during the next 4 years of follow-up. Patients were allocated to one of the following treatment modalities: an implant-retained overdenture (IRO-group, 2 endosseous implants, n = 61) or a complete denture (CD-group, n = 60). One year after placement of the denture, unsatisfied patients of the CD-group got the opportunity for a retreatment including an implant-retained overdenture. In the IRO-group 4 implants were lost during the first year and again 4 implants were lost during the next 4 years (survival rate: 93%). All patients could be re-operated successfully. In the CD-group 14 patients (23%) chose an implant-retained overdenture after 1 year. Patients of the IRO-group were significantly more satisfied than patients of the CD-group after 1 year (satisfaction score 8.3 versus 6.6, scale 1-10) and after 5 years (7.4 versus 6.4). From this study it can be concluded that endosseous implants have a high survival rate after 5-years' follow-up. Satisfaction score of the IRO-group is diminishing in time, probably because patients get used to an improved situation. After 5 years, the mean satisfaction score of the CD-group (including patients who got implants) was still lower than of the IRO-group, in spite of the opportunity to a retreatment and have implant-retained overdentures.

Alveolar Bone Loss↗

PubMed1998

The mandibular staple bone plate: a long-term retrospective evaluation.

PURPOSE: Clinical and radiographic parameters and denture satisfaction were evaluated in a long-term retrospective study of patients treated with the mandibular staple bone plate. PATIENTS AND METHODS: Fifty-six edentulous patients were treated with the mandibular staple bone plate to stabilize their lower denture. The mean evaluation period was 103 months (range, 84 to 139 months). Peri-implant mucosa and bone height were scored, together with quality of the prosthesis and prosthodontic maintenance care. Denture satisfaction was assessed by using two questionnaires. RESULTS: Four staple bone plates were removed during the evaluation period, and one appeared to be fractured. The remaining 51 staple bone plates were functional without any signs of major complications (survival rate, 91%). No further alveolar resorption in the interforaminal region of the mandible took place during the evaluation period. Patients were very satisfied with the prosthetic construction. CONCLUSIONS: The mandibular staple bone plate is a good modality to stabilize the lower denture. However, endosseous implant systems are preferred because of comparable success rates with a more simple operative procedure.

Adult↗

PubMed1998

Mandibular overdentures supported by two or four endosteal implants. A prospective, comparative study.

The aim of this prospective study was to evaluate the effect of the number of implants supporting a mandibular overdenture on the condition of the peri-implant tissues. Sixty edentulous patients (Cawood class V VI) participated in this study. After randomization, thirty patients were treated with an overdenture supported by two IMZ implants (group A) and thirty patients with an overdenture on four IMZ implants (group B). The implants were inserted in the anterior region of the mandible. After three months overdentures were constructed, supported by round bar and clip attachments. A standardized clinical and radiographic evaluation was performed 0, 6 and 12 months after insertion of the denture. One implant was lost (group A) during the healing period. There were no significant differences with regard to any of the studied clinical or radiographic parameters of the peri-implant tissues, neither were significant differences found between the lateral and central implants in group B. None of the patients reported a sensory change in lip or chin region. From this study it is concluded that there seems to be no need to insert more than two endosteal implants to support an overdenture, however, long-term prospective studies are needed to support this notion.

Adult↗

PubMed1998

Mandibular overdentures supported by two Brånemark, IMZ or ITI implants. A prospective comparative preliminary study: one-year results.

The aim of this prospective comparative study was to evaluate the condition of the peri-implant tissues of three different implant systems supporting a mandibular overdenture. Ninety edentulous patients (Cawood class V-VI) participated in this study. After randomization, 30 patients were treated with 2 Brånemark implants, 30 patients with 2 IMZ implants and 30 patients with 2 ITI implants. The implants were inserted in the canine region of the mandible. After 3 months overdentures were fabricated supported by a round bar and clip attachment. A standardized clinical and radiographic evaluation was performed 0,6 and 12 months after insertion of the denture. The intraoral radiographs were made, using the long-cone technique with an aiming device. Two implants were lost (1 Brånemark, 1 IMZ) during the healing period. None of the patients showed any sensory change in lip or chin region. The pocket depth in the Brånemark group decreased significantly whereas the mucosa recession increased significantly in both the Brånemark as well as in the IMZ group. After 12 months, there was significantly less bone loss in the ITI group. From our study it was concluded that 2 (Brånemark, IMZ or ITI) implants placed in the interforaminal region connected with a bar supply a proper base for the support of a mandibular overdenture in the (Cawood V-VI) edentulous patient. The ITI implant appears to be the implant of choice for mandibular overdenture therapy, because only one operation is required for a comparable result.

Adult↗

PubMed1995

Patient satisfaction with implant-retained mandibular overdentures. A comparison with new complete dentures not retained by implants--a multicentre randomized clinical trial.

OBJECTIVES: The aim of this study was to establish the treatment outcome of full denture treatment with or without implant support, in which the outcome assessment focuses on the patient's subjective evaluation ('denture-satisfaction'). DESIGN: A multicenter randomized clinical trial. SUBJECTS: Thirty-two men and 118 women (mean age 56 +/- 9, range 35-84 years) participated in the study. The mean height of the mandible was 13 +/- 2 mm, measured on a lateral cephalometric radiograph. The patients were randomly assigned to either a group treated with implant-retained mandibular overdentures and a new maxillary denture, or to a control group treated with a new set of complete dentures. MAIN OUTCOME MEASURES: Denture satisfaction was assessed using questionnaires focusing on denture-related complaints and 'a general satisfaction rate'. RESULTS: Based on the baseline data, from the 'denture complaints' questionnaire six interpretable factors could be extracted. One factor did not vary following treatment and was excluded from the outcome analysis. At the 1-year evaluation three out of five factors showed significantly better scores for the group treated with implants than for the control-group. The same was found for the general satisfaction rate. CONCLUSION: For patients with a severely resorbed mandible, overdentures retained by dental implants appear to provide a more satisfactory solution to their denture-related problems.

Adult↗

PubMed1995

The incomprehensible success of the implant stabilised overdenture in the edentulous mandible: a literature review on transfer of chewing forces to bone surrounding implants.

The approach of implant stabilised overdentures has become one of the routine treatment modalities for compromised edentulous ridges. The purpose of this literature review is to analyze survival rates of loaded implants, occlusal forces and stress distributions of implant stabilised overdentures in edentulous mandibles and of fixed loaded implants at least over a medium-term period. which is comparable with fixed prostheses. Patients with implant stabilised overdentures and with fixed bridges on implants generate similar occlusal forces. The number of implants under a prosthetic construction seems to have less influence on stress distribution than design of the superstructure and related direction of forces.

Alveolar Process↗

PubMed1993

Augmentation of the maxillary sinus floor with autogenous bone for the placement of endosseous implants: a preliminary report.

Placement of endosseous implants in the atrophic maxilla is often restricted because of lack of supporting bone. In this article, experience with augmentation of the maxillary sinus floor with autogenous bone grafts to enable insertion of endosseous implants is described. The technique is aimed at providing a cortical layer on top of the graft to ensure a reliable seal of the maxillary sinus and to achieve optimal stability of the bone graft in case of simultaneously placement of dental implants. The procedure was used in 25 patients, using iliac crest grafts (22 patients, 86 implants), symphyseal bone grafts (two patients, six implants), or a maxillary tuberosity bone graft (one patient, one implant). Ninety-three Brånemark implants (Nobelpharma, Götenburg, Sweden) were inserted in 47 grafted maxillary sinuses. The mean follow-up was 16 months (range, 6 to 36 months). No inflammation of the bone grafts nor of the maxillary sinus occurred. The sinus membrane was perforated accidentally in eight cases during the surgical procedure. Five implants (5.4%), all inserted in iliac crest grafts, were lost during the healing period. The patients received implant supported overdentures (16 patients) or bone-anchored bridges (nine patients). From this preliminary study it is concluded that augmentation of the maxillary sinus floor with bone grafts for the insertion of endosseous implants is a promising solution for patients with atrophic maxillae and functional problems with their partial or full dentures.

Adult↗

PubMedDate not supplied

Psychosocial effects of implant-retained overdentures.

The aim of this study was to compare implant-retained mandibular overdentures and two conventional treatments for their effects on functional ability (chewing, speaking, etc), patient satisfaction, and quality of life (psychosocial functioning). Assignment of 90 patients was executed by means of a balancing allocation computer program to ensure the pretreatment comparability of the three groups. Twelve months after treatment, the average scores for almost all specific quality-of-life measures had improved significantly in all three groups. On average, all patients experienced fewer restrictions in their social activities and had fewer psychological problems because of their full dentures. No impact on the general quality of life was established. One year after treatment, all three dental treatment modalities had a comparably positive effect on dental health-related quality of life.

Analysis of Variance↗