Stability Of Overdentures Research Articles

Prosthodontic Rehabilitation of Missing Dentition Using Multi Unit Precision Attachment Hybrid Overdentures–Clinical Report of Two Patients

Prosthodontic rehabilitation of a patient with terminal dentition is very challenging. Any conservative treatment that can delay or eliminate future prosthodontic problems should be considered. Complete and partially edentulous patients are generally unsatisfied due to the inherent instability of dentures during functional and parafunctional movements which results due to the lack of adequate supporting hard and soft tissues. Inspite of rapid development and good success rate in the field of implantology, preservation of remaining natural teeth or roots is more desirable which supports Devan’s dictum. Overdenture is a complete or partial denture prosthesis supported partly by soft tissues and partly by retained natural teeth or its roots or implants. Overdenture increases the retention, stability and support, improves the masticatory efficiency, preserves the alveolar bone and muscular patterns and preserves sensory receptors within the periodontal ligament which increases manipulative skills in handling the denture. Retention and stability of overdentures can be improved by attachments or magnets. Fixed partial denture is not an option when there is no distal abutment. The solution of such a critical situation is to give combined or hybrid prosthesis. A combined prosthesis carries the advantage of fixed removable prostheses without surgical intervention, where an acrylic prosthesis is retained with an extra coronal attachment to tooth. This paper presents a twin patient report of rehabilitation of a mandibular and maxillary terminal dentition with a combined prostheses of acrylic retained by extra coronal precision attachment system (Rhein 83, Italy)

THE EFFECT OF TWO DIFFERENT ATTACHMENTS WITH IMPLANT RETAINED MANDIBULAR OVERDENTURES ON PATIENT SATISFACTION AND MASTICATORY FUNCTION

Background: Dental implants have solved all of the problems of retention and stability of conventional complete dentures. The improved retention and stability of overdentures retained by two, three or four implants have resulted in an improvement in overall patient satisfaction, together with improvement in the chewing ability and biting force. The choice of selection of the type of attachment will mainly depend upon the need for stabilization against horizontal forces. Rigid attachments have been advocated to provide optimum stabilization against horizontal forces.Materials and Methods: Three interforaminal implants have been installed in the edentulous mandible of twelve completely edentulous patients. After 3 month from implant installation the patients were randomly divided into two equal groups; the first group received a ball attachment, while the second group received a parallel wall telescopic attachment. All patients received new complete dentures fabricated with a chroum-cobalt framework embedded in the fitting surface of the denture. Satisfaction, masticatory ability and the biting force were recorded for all patients in both groups at the following intervals; before implant installation, 2 weeks after loading, 3 month after loading and after a 1 year follow up.Results: There was a statistically significant improvement in patient satisfaction between the conventional complete denture before implant installation and the implant supported overdenture after implant installation, with in each group of patients. When comparing between the two groups, there was no statistically significant difference with regards to patient satisfaction , chewing ability and biting force after a 1 year follow up, with a slightly higher mean score value in the telescopic attachment group.Discussion: Placement of 3 interforamenal implants with ball attachment with a chrome-cobalt framework embedded in the fitting surface of the complete dentures have limited the resiliency of the ball attachment and so decreased the liability of movement or fracture of the overdenture. When comparing the splinted ball attachment with the rigid splinted parallel wall telescopic attachment,

Comparison of the Effect of Ball and Bar Attachment Designs on Retention and Stability of Mandibular Implant-Supported Overdentures

Objectives The present study evaluated the effect of bar and ball attachment designs on retention and stability of a mandibular overdenture supported by four implants.Methods An edentulous mandibular acrylic resin model with four implants in the anterior part of the ridge (A, B, D and E) was fabricated. A metal framework simulating the overdenture was also fabricated. Totally, 30 overdentures were divided into three groups based on the attachment design; BL: Four ball attachments in A, B, D and E positions; BB: One bar attachment between B and D positions and two ball attachments at positions A and E; BR: Bar attachments between the positions A, B, D and E with two posterior extensions. To evaluate the retention and stability of the overdenture, tensile dislodging forces were applied in three directions of vertical, oblique and anterior- posterior by a universal testing machine. One-way ANOVA and Tukey’s HSD test were performed to analyze the data. All tests were carried out at 0.05 level of significance.Results There were statistically significant differences between the groups in the peak load (P < 0.001). The peak load values for vertical, oblique and anterior-posterior dislodging forces were the highest for BL with 49.38 ± 2.19 N, 52.19 ± 1.44 N, and 49.03 ± 5.89 N, respectively, while these values were the lowest for BR with 29.78 ± 2.52 N, 12.10 ± 0.45 N, and 6.26 ± 0.45 N, respectively.Conclusion The attachment designs affected the retention and stability of mandibular implant-supported overdentures.

Cinco anos de acompanhamento de overdenture dento-suportada como solução protética para pacientes idosos: Série de Casos

Purpose: This is a case series report with up to five-year follow-up of preservation of remaining teeth used as retentive attachments to support an overdenture. Case Description: A valuable treatment to achieve immediate retention and stability was performed by using the patient’s remaining teeth with root-retained attachments combined with an overdenture. All overdentures were considered successful at the 5-year follow-up. Conclusion: Within the limitations of this case series, the use of short-coping and ball attachments to improve the retention and stability of overdentures is recommended. This treatment option is usually related to limited financial resources or to any health restraint.

Comparison of Retention and Stability of Implant-Retained Overdentures Based upon Implant Number and Distribution

The purpose of this investigation was to evaluate the effects of number and distribution of implants upon in vitro dislodging forces to a simulated implant-supported overdenture and to examine differences between several different attachment systems. An experiment was undertaken utilizing a model simulating a mandibular edentulous ridge with dental implants in positions on the model approximating tooth positions in the natural dentition. A cobalt-chromium-cast testing framework was used to measure the peak load required to disconnect an attachment. Four different types of commercially available attachments were used in various positions on the model in sequence to evaluate the effects of retention and stability of overdentures based on implant number and distribution: (1) ERA, (2) O-Ring, (3) Locator, and (4) Ball. For each group, 10 measurements were made of peak dislodging forces. Means were calculated and differences among the systems, directions, and groups were identified using a repeated measured analysis of variance (α = .05). The interactions between the attachment system, direction of force, and implant number and distribution were statistically significant. Vertical dislodging forces of the simulated overdenture prosthesis increased with additional widely spaced implants. Oblique dislodging forces of the simulated prosthesis increased with additional widely spaced implants except in the two-implant model with all attachments, and in the four-implant groups with Locator attachments. Anteroposterior dislodging forces of a simulated overdenture prosthesis increased with additional widely spaced implants except in the four-implant groups with Ball and Locator attachments. Ball attachments reported the highest levels of retention and stability followed by Locator, O-Ring, and ERA. Within the limitations of this study, retention and stability of an implant overdenture prosthesis are significantly affected by implant number, implant distribution, and abutment type.

Stability of Mandibular Overdentures Before and After Attachment Wear. An in vitro Study

Purpose: The aim of this research was to evaluate and compare the maximum stabilizing force and stabilizing energy of mandibular overdentures with several attachments during anterior, lateral, and posterior dislodgement before and after wear simulation. Changes in the maximum retentive force and maximum stabilizing force of each attachment during various levels of wear simulation were also examined.Methods: Ten samples, each of 8 different overdenture attachments, were sequentially embedded in mandibular overdentures in pairs. Maximum stabilizing force and stabilizing energy were measured during anterior, lateral, and posterior dislodgement by a universal testing machine before and after wear simulation. A total of 5000 insertion-removal cycles were performed. The maximum retentive force of each sample was measured during various levels of wear simulation by a micro material testing machine.Results: The mean maximum stabilizing force ranged from 1.94N to 28.6N, and the mean stabilizing energy ranged from 1.9N•mm to 30.24N•mm before wear simulation. After wear simulation, the values ranged from 1.03N to 20.49N for maximum stabilizing force and from 1.9N•mm to 21.51N•mm for stabilizing energy. This study revealed a decrease (4.13-84.46 %) and an increase (1.23-41.8 %) in maximum stabilizing force. A decrease (6.5-85.42%) and increase (5.35-23.55%) were also seen for stabilizing energy.Conclusions: Maximum stabilizing force and stabilizing energy can each be used to evaluate the stability of overdentures. Both parameters were different during anterior, lateral, and posterior dislodgement after and before wear simulation. The changes in the maximum retentive force for each attachment during wear simulation were different. Among the attachments tested, Hyperslim 4013 was the least sensitive to wear simulation.

Retention and wear of precision-type attachments

I recision-type attachments are commonly used to enhance the retention and stability of overdentures. This not only adds considerably to the overall cost of the treatment but also increases the potential for detrimental forces to be transmitted to abutment teeth, thus reducing their longevity. The aim of this study was to measure in the laboratory the force required to disengage selected attachments and relate this to the retention provided over the possible length of service of the denture.