Journal of Oral Implantology June 2013 - (Page 293)

RESEARCH In Vitro Analysis of Resistance to Cyclic Load and Preload Distribution of Two Implant/Abutment Screwed Connections Giovanna Murmura, PhD Donato Di Iorio, DDS, PhD* Angelo Raffaele Cicchetti, DDS Bruna Sinjari, DDS Sergio Caputi, MD, DDS The aim of the present research is an in vitro evaluation of the preload distribution in screw-retained implant systems under cyclic load. Two implant systems with internal connection were tested: fifteen 4.5 3 10 mm implants with internal hexagon and fifteen 4.5 3 10 mm implants with internal octagon. Samples underwent cyclic load that was between 20 N and 200 N for 1 3 106 cycles. After mechanical tests, samples were sectioned along the long axis and analyzed under a scanning electron microscope. Five 4.5 3 10 mm implants with internal hexagon and five 4.5 3 10 mm implants with internal octagon were collected for photoelastic analysis. Each fixture was mounted in a wax-made parallelepiped measuring 20 mm 3 20 mm 3 10 mm. A mold was made for each wax parallelepiped/fixture assembly using a silicone-based impression material, and an epoxy resin was poured in each mold. After setting of the resin, 258 angled titanium abutments were screwed onto each replica; afterwards, assemblies underwent photoelastic analysis. After cyclic load, screw threads and heads were still in contact with internal fixture threads and abutment holes, respectively, suggesting that preload has not been ˜ lost during load. During load, SSO and Xsign implants behave in a different way. SSO samples revealed the ˜ presence of fringes radiating from the base of the abutment. Xsign implants showed the presence of fringes radiating from the threads of the retention screw. From the present in vitro research, it is possible to state that screw-retained abutment based on an internal octagonal connection is less likely to come loose after cyclic load. Key Words: Implant,abutment-fixture connection,cyclic load INTRODUCTION F ailures of implant-supported prosthesis represent an eventuality difficult to be managed by clinicians. Fixture or screw fracture, in fact, could give rise to the failure of the prosthodontic rehabilitation; 1 Adell et al reported a fixture fracture rate of 5%, while Schwarz2 reported a failure rate of 12.5% for maxillary implants and 14.3% for mandibular implants. Department of Stomatology and Oral Sciences and Ce.S.I, University ‘‘G. d’Annunzio’’ of Chieti-Pescara, Italy. * Corresponding author, e-mail: DOI: 10.1563/AAID-JOI-D-10-00144 As regards the screwed systems, screw loosening has been reported to be the most recurrent complication,3 and many researchers state that the associated abutment mobility could compromise the survival of the rehabilitation.4–6 However, it is generally accepted that the screw loosening occurs most frequently in single crown implant restorations rather than in implant-supported bridges.7 Preload applied during screw tightening and the fit between implant components are both crucial elements in providing a durable stability to the implant-abutment complex. McGlumphy et al8 report that the preload is dependent on the Journal of Oral Implantology 293

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