Mandibular implant-supported overdentures and oral function.

OBJECTIVES: Oral 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. MATERIALS AND METHODS: Eighteen 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. RESULTS: At 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). CONCLUSION: Maximum 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.

[Patient satisfaction with different types of implant-retained overdentures in the edentate mandible]. / Patiënttevredenheid met verschillende mesostructuren op implantaten in de edentate onderkaak.

The purpose of this study was to determine patient satisfaction with implant supported mandibular overdentures using magnet, bar-clip and ball-socket attachments, and to assess the relation between maximum bite force and patient satisfaction. In a crossover clinical trial, 18 edentulous patients with lower denture complaints received 2 mandibular implants and new lower and upper dentures. The lower denture initially came without any kind of attachment system, but was fitted with one of the attachment types after 3 months. The attachments were changed 3 months thereafter, in random order. A questionnaire concerning denture complaints was given at baseline (with the old denture), after 3 months of functioning with the new denture without attachments and after 3 months of functioning with each of the attachments (within-subject comparison). In addition, at the end of the experiment patients were asked to express their overall satisfaction with their dentures on a visual analogue scale (VAS). Data regarding maximum bite force were obtained from a previous study with the same population. Mandibular implant supported overdenture treatment reduced various denture complaints. The VAS score reflected patients' preference more accurately than scale-scores. Patients strongly preferred bar-clip (10 subjects) and ball-socket attachments (7 subjects) over magnet attachments (1 subject). Patients' preference could not be predicted on the basis of baseline observations. Maximum bite force was not correlated to scale- or VAS scores.

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 effect of an occlusal stabilization splint and the mode of visual feedback on the activity balance between jaw-elevator muscles during isometric contraction.

The aim of the present study was to gain an insight into the influence of a vertical bite-rise (clenching in intercuspal occlusion vs. clenching on an occlusal stabilization splint), the mode of visual feedback (VF; obtained from the compound masseter signal, from the compound anterior temporalis signal, or from the compound signal of both masseter and anterior temporalis muscles) and the EMG clenching level (10% MVC and 50% MVC) on the muscle balance between the masseter and the anterior temporalis muscles. The muscle balance was quantified as the logarithmic value of the ratio between the summated mean rectified EMG activity of the masseter muscles and this activity of the anterior temporalis muscles. The muscle balance was influenced significantly by the mode of VF (p < 0.01), the muscle balance shifting toward the group of muscles from which VF was obtained. When VF was obtained from the masseter muscles, a decrease in the anterior temporalis EMG activity was observed when the vertical dimension was increased (p < 0.05-0.01). When VF was obtained from the anterior temporalis muscles, the activity of the masseter muscles was raised with respect to that of the anterior temporalis muscles during clenching with a vertical bite-rise (p < 0.05-0.01). When VF was obtained from both groups of muscles, the masseteric EMG activity increased, whereas the anterior temporalis EMG activity decreased. Hence, regardless of the mode of VF, a relatively lower activity level of the anterior temporalis muscles was achieved after insertion of an occlusal stabilization splint.(ABSTRACT TRUNCATED AT 250 WORDS)

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 use of the transmandibular implant system in extreme atrophy of the mandible; a retrospective study of the results in two different hospital situations.

This retrospective study aims to investigate and compare the results obtained with the transmandibular implant (TMI) in two different hospital situations. Group I were patients treated in a teaching hospital since 1984 by a varying group of surgeons and prosthodontists with a varying degree of experience with the TMI. Group II were patients treated in 1993 and 1994 by experienced surgeons and prosthodontists in the hospital where the TMI was originally developed. In group I, a relatively high frequency of reversible (45.4%) and irreversible--i.e. implant loss--(15.2%) complications occurred. In group II, no implants were lost and reversible complications were reported in 10.8% of the patients. In general, the patients of both groups were quite satisfied with the result of the treatment. In both groups, limited bone loss around the implant posts could be observed. An increase in the height of the mandibular bone distal of the lateral posts was frequently observed, especially in group II. It is concluded that both very favourable and less favourable results can be obtained with the TMI. In this study the best results are found in a highly specialized TMI centre, where patients are treated--with only uncompromised implant-posts--by a small group of experienced surgeons and prosthodontics with accurate application of the existing guidelines.