Marco S. Cune

Masticatory Function with Implant-supported Overdentures

The type of attachment that is used in implant-supported mandibular overdentures may influence the retention and stability of the prosthesis and, thus, masticatory function. In this within-subject cross-over clinical trial, we examined the hypothesis that greater retention and stability of the overdenture improve the masticatory function. Eighteen edentulous subjects received 2 oral implants, a new overdenture, and, successively, 3 different suprastructure modalities: magnet, ball, and bar-clip. Masticatory performance, masticatory efficiency, and swallowing threshold were measured. The masticatory function significantly improved after implant treatment with each of the 3 attachments. We observed small differences in masticatory function among the 3 attachment types: slightly better masticatory performance with ball and bar-clip than with magnet attachments. The number of chewing cycles until swallowing hardly decreased after implant treatment. We conclude that significantly better masticatory performance, combined with a slightly smaller number of chewing cycles after implant treatment, results in smaller food particles being swallowed.

The Influence of Various Attachment Types in Mandibular Implant-retained Overdentures on Maximum Bite Force and EMG

The type of attachment that is used in oral rehabilitation by means of implant-retained mandibular overdentures may influence the retention and the stability of the denture. In this study, we examined the hypothesis that a better retention and stability of the denture improve the oral function. Eighteen edentulous subjects received 2 permucosal implants, a new denture, and, successively, 3 suprastructure modalities. Maximum bite force and electrical activity of the masseter and temporalis muscles were measured. The maximum bite force nearly doubled after treatment for each of the 3 attachments. However, the average bite force after treatment was still only two-thirds of the value obtained for dentate subjects. No large differences in maximum bite force and muscle activity were found among the 3 attachment types. Temporalis activity was significantly lower than masseter activity when subjects clenched without implant support. There was no difference in activity when subjects clenched with implant support.

The combined use of endosteal implants and iliac crest onlay grafts in the severely atrophic mandible: a longitudinal study

Thirteen patients, who received an onlay bone graft augmentation to their severely atrophic mandible in combination with a simultaneous implant insertion, were studied prospectively. A reproducible method that allowed for accurate assessment of graft resorption, consisting of lateral and oblique-lateral cephalometric radiographs in combination with an image analysis system, was used to assess the resorption rate in all patients and between subgroups of patients, according to selected patient and treatment characteristics. Thirty implants were placed, none of which were lost, and all patients expressed satisfaction after a mean observation period of 877 days. A mean resorption rate of 36% of the grafted bone height occurred, mainly during the first year and with some degree of individual variance. After three years the resorption had virtually stopped. No statistically significant differences between any of the subgroups of patients could be distinguished. Peri-implantitis was found around eight implants in seven patients. It is concluded that the described surgical technique should be used only if there are stringent indications.

Treatment outcome with implant-retained overdentures: Part II—Patient satisfaction and predictability of subjective treatment outcome

The purpose of this study was to determine the effects of implant-overdenture treatment (IOT) on patients complaints about dentures and the degree to which subjective treatment outcome could be predicted from baseline patient and treatment characteristics. Four groups of patients were distinguished: one pretreatment group, two posttreatment groups (1 year after treatment) and one reference group of denture wearers, who had not applied for any kind of treatment. They finished a questionnaire with 20 statements on denture complaints. Four scales concerning denture complaints could be distinguished and named after their underlying variables. Differences between the groups were analyzed. IOT treatment was shown to be very effective on a wide range of denture complaints. Little change was seen in patient satisfaction with regard to maxillary dentures when measured on the scales, although many patients wanted improvement in retention and stability for the maxillary denture after IOT treatment in the mandible. Sixteen percent of the denture wearers who had not applied for IOT expressed complaints regarding their mandibular dentures that matched or were more severe than those of the patients that had applied for IOT, before the actual start of treatment. Although generally the subjective treatment outcome of IOT was favorable, it could not be individually predicted from baseline patient and treatment characteristics.

Mandibular implant‐supported overdentures and oral function

OBJECTIVESnOral rehabilitation by means of implant-retained mandibular overdentures is known to improve oral function. The aim of this study was to evaluate the long-term effects of mandibular implant treatment on oral function. We quantified maximum bite force and masticatory performance 10 years after implant treatment. It was hypothesized that these outcome measures would not change in this period.nnnMATERIALS AND METHODSnEighteen edentulous patients were scheduled for re-evaluation of their oral function 10 years after they had participated in a randomized cross-over clinical trial. In that trial, they had received two mandibular implants and a new denture with successively magnet-, ball-socket, and bar-clip attachments.nnnRESULTSnAt the 10-year follow-up, 14 of the initial 18 patients participated in the evaluation. As a result of the implant treatment, the average maximum bite force more than doubled, from 162 to 341 N, whereas the average number of chewing cycles to halve the initial particle size decreased from 55 to 27 cycles. No significant changes in maximum bite force and masticatory performance were observed after 10 years. However, the average maximum bite force obtained with implant-retained overdentures is still significantly lower than that of dentate subjects (569 N).nnnCONCLUSIONnMaximum bite force and masticatory performance significantly increased after implant treatment and remained unaltered during the following 10-year period. Thus, implant treatment greatly improves oral function for a long period of time.

Treatment outcome with implant-retained overdentures: Part I—Clinical findings and predictability of clinical treatment outcome

This nationwide study was conducted to clinically evaluate treatment with implant-retained overdentures when applied on a large scale and to determine to what degree treatment results could be predicted from patient and treatment characteristics at baseline. A total of 429 patients who had received implant overdenture treatment were clinically investigated by two dentists. Implant survival was high, especially for implants placed in the mandible. Results for the maxilla appeared far less promising. Complications that were observed predominantly concerned inflammation of the peri-implant tissues and poor oral hygiene. The quality of the overdentures, as assessed on three conventional prosthetic parameters, was generally good. Nevertheless, overdentures on oral implants appear to require considerable maintenance. No statistically significant correlation could be found between patient and treatment characteristics at baseline and the clinical treatment outcome. So, although treatment outcome with implant-retained overdentures appeared favorable, clinical results were not individually predictable.

Dental treatment needs in Dutch nursing homes offering integrated dental care

The purpose of this study was to determine the dental treatment needs of the residents in nursing homes (NHs) where integrated dental care has been offered without financial barriers. The dental status and surgical, prosthetic, restorative, and periodontal treatment needs were determined for 432 residents (average age 78.8 years) in three Dutch NHs. Although the subjects had no complaints, 72% had dental treatment needs. It was determined that treatment was necessary for 64% of the edentulous subjects (N = 316), 100% of the partially dentate subjects (N = 76), and 87% of the fully dentate subjects (N = 40). We concluded that when residents can no longer carry out oral hygiene independently, it is very difficult for them to maintain a level of oral health where their dental treatment needs have been met, especially for dentate residents.

Dentofacial characteristics of patients with hypodontia

This study aims to identify distinctive dentofacial characteristics of hypodontia patients. For this purpose, 189 young hypodontia patients (cases) were divided into subgroups, based on criteria from literature. Normalised differences between cases and controls were calculated for various parameters of dentofacial form. Subsequently, cluster analysis was applied to disclose subsets of hypodontia patients with distinctive dentofacial features. The ANB angle, interincisal angle and lower anterior face height were consistently significantly different amongst the subsets. Four clusters of patients with an increasing number of missing teeth and distinctive dentofacial characteristics could be identified. Patients in cluster 1 display a high-angle facial pattern. Patients in clusters 2 and 3 exhibit markable dentoalveolar characteristics (a relatively small and a large interincisal angle, respectively). Patients in cluster 4 exhibited notable sagittal–skeletal discriminative features predominantly because of a retrognathic maxilla. The smallest nasolabial angle and lower anterior face height were seen in this cluster. It is concluded that the anterior–posterior relationship between the jaws, the interincisal angle and the lower anterior face height are discriminative parameters of dentofacial form in hypodontia patients. Patients with hypodontia can be clustered in four groups, each with distinctive vertical–skeletal, dentoalveolar and sagittal–skeletal characteristics. This categorisation of patients with hypodontia into meaningful groups may be useful for treatment planning, interdisciplinary communication and as a means of identifying groups of patients that qualify for reimbursement of costs. Other dental factors should be appreciated as well during restorative clinical decision making in patients with hypodontia.

Flexible (Polyactive®) versus rigid (hydroxyapatite) dental implants

In a beagle dog study, the peri-implant bone changes around flexible (Polyactive) and rigid hydroxyapatite (HA) implants were investigated radiographically by quantitative digital subtraction analysis and by assessment of marginal bone height, with the aid of a computerized method. A loss of approximately 1 mm of marginal bone height was observed for both the dense Polyactive and the HA implants, after 6 months of loading. This value appeared to be stable from 12 weeks of loading onward. Along the total length of the implant during the first 6 weeks of loading, both the flexible (dense Polyactive) and the rigid (HA) implants showed a decrease in density. However, after this 6-week period, the bone density around the implants increased, and after 18 weeks the original bone density was reached. The flexible Polyactive implants provoked less decrease in density than the rigid HA implants, although not to a statistically significant level. This finding sustains the hypothesis that flexible implant materials may transfer stresses to the surrounding bone more favorably.

A nationwide evaluative study on implant-retained overdentures

OBJECTIVESnIn the Netherlands, dental implants have been included in the National Dental Insurance Scheme (NDIS) since 1989. Nowadays, out-of-pocket expenditure is low, making implant treatment financially feasible for a large group of edentulous, potential implant candidates. Treatment can be performed by both oral surgeons and general dentists. Results of implant treatment in the literature are usually obtained in academic and specialized centers. In contrast to this, the present study evaluates the quantitative and qualitative aspects of rehabilitation with oral implants in combination with an overdenture when applied on a nationwide scale.nnnMETHODSnFor this purpose all patients (n = 5410) treated between January 1989 and July 1992 were extensively documented pre-operatively, implant patients (n = 429) were clinically investigated by two independent observers and the effect of treatment on denture complaints was assessed by means of a questionnaire (n = 460).nnnRESULTSnOnly a small proportion of the potential pool of implant candidates is actually being treated, to a constant number of approximately 2000 patients a year. The selected patients have major denture problems and have received relatively high levels of prosthetic care during the last decade. Clinical results are comparable to those reported in the literature, implant survival after 3 years for the lower jaw being 96.3% and for the upper jaw 70.4%. Oral hygiene was frequently considered suboptimal and seen in conjunction with marginal inflammation of the peri-implant mucosa. Subjective results were excellent, patients were quite satisfied with the improvements in the comfort and esthetics of their lower denture.nnnCONCLUSIONSnImplant-overdenture treatment, within the guidelines and regulations set by the Dutch NDIS, is a safe and effective treatment alternative, in particular for the rehabilitation of the lower jaw.