Journal of Oral Implantology June 2013 - (Page 302)

RESEARCH Mandibular Implant-Supported Overdenture: An In Vitro Comparison of Ball, Bar, and Magnetic Attachments V. Manju, MDS* T. Sreelal, MDS In an implant-supported overdenture, the optimal stress distribution on the implants and least denture displacement is desirable. This study compares the load transfer characteristics to the implant and the movement of overdenture among 3 different types of attachments (ball-ring, bar-clip, and magnetic). Stress on the implant surface was measured using the strain-gauge technique and denture displacement by dial gauge. The ball/O-ring produces the optimal stress on the implant body and promotes denture stability. Key Words: overdenture, ball and ring, bar and clip, magnetic attachment INTRODUCTION T raditional mandibular dentures have limited retention and stability as they rest on the moving foundation provided by the mandible and its associated musculature. In the maxilla, the ability to cover a broader foundation presents the opportunity to fabricate a more retentive and stable denture. Implant-supported overdentures are mainly useful for mandibular ridges, as they have undergone resorption and offer better retention than traditional dentures. However, the cost of implants is quite high; hence, the use of fewer implants (2 instead of 4) offers a less expensive option for an edentulous patient.1 Nevertheless, stability cannot be compromised and should be given equal consideration. Placement of the implants for overdentures in the mandible should be planned explicitly, as masticatory load transmission in mandibular implant-supported overdentures differs substantially from that of implant-supported fixed restorations.2 In general, an implant should be loaded through axial forces. Importance should also be given to location and the number of implants being placed Amrita Institute of Medical Sciences, Kochi, Kerala, India. * Corresponding author, e-mail: DOI: 10.1563/AAID-JOI-D-11-00050 302 Vol. XXXIX /No. Three / 2013 in the dental arch, as well as the chewing function as horizontal forces and even moments can cause implant failure if these are ignored. Mandibular implant-supported overdentures are generally retained by at least 2 implants, which are placed in, or slightly medial to, the canine area.3 The commonly used forms of anchorage include ball attachments,4 clips on a bar connecting the implants,5 and magnetic attachments.6 Overdenture stability is a key factor for patient satisfaction7 and is dependent on the ability of the implants to withstand occlusal loads. It is hence important to ascertain whether implants need to be splinted together or whether freestanding implants alone can withstand the loads. The present in vitro study compared the load transfer characteristics to the implant and the movement of implant-supported overdentures among the 3 different types of attachments (ball and ring, clips on a bar, and magnetic). The objectives of the study were to compare the following:    Strain around the implant at the loading side and the nonloading side Bending moment transferred from the implant into the bone Denture displacement in mediolateral, upwarddownward, and backward-forward directions

Table of Contents for the Digital Edition of Journal of Oral Implantology June 2013

Congratulations to Duke Heller, DDS, MS—Pioneer, Teacher, and Mentor
In Vitro Analysis of Resistance to Cyclic Load and Preload Distribution of Two Implant/ Abutment Screwed Connections
Mandibular Implant-Supported Overdenture: An In Vitro Comparison of Ball, Bar, and Magnetic Attachments
An Exploratory Study on Assessment of Gingival Biotype and Crown Dimensions as Predictors for Implant Esthetics Comparing Caucasian and Indian Subjects
A New Approach to the All-on-Four Treatment Concept Using Narrow Platform NobelActive Implants
Regular and Switching Platform: Bone Stress Analysis With Varying Implant Diameter
Comparison Between Immediate and Delayed Laser-Treated Implants Surface With Switching Platform: A Clinical Retrospective Study
Effect of a Multiporous Beta–Tricalicum Phosphate on Bone Density Around Dental Implants Inserted Into Fresh Extraction Sockets
The Effect of Varying Implant Position in Immediately Loaded Implant-Supported Mandibular Overdentures
Bone Regeneration Around Immediate Implants Utilizing a Dense Polytetrafluoroethylene Membrane Without Primary Closure: A Report of 3 Cases
Socket Preservation and Sinus Augmentation Using a Medical Grade Calcium Sulfate Hemihydrate and Mineralized Irradiated Cancellous Bone Allograft Composite
Implant Placement and Immediate Loading With Fixed Restorations in Augmented Sockets. Five-Year Results. A Case Report
Immediate Placement and Provisionalization With Buccal Plate Preservation: A Case Report of a New Technique
Clinical Importance of Recipient Site Characteristics for Vertical Ridge Augmentation: A Systematic Review of Literature and Proposal of a Classification
Postextraction Implant in Sites With Endodontic Infection as an Alternative to Endodontic Retreatment: A Review of Literature
Letter to the Editor

Journal of Oral Implantology June 2013