Journal of Oral Implantology June 2014 - (Page 239)

RESEARCH A Comparative Study on Microgap of Premade Abutments and Abutments Cast in Base Metal Alloys Jaini Jaini Lalithamma, MDS1* Sreekanth Anantha Mallan, MDS2 Pazhani Appan Murukan, MDS3 Rita Zarina, MDS4 The study compared the marginal accuracy of premade and cast abutments. Premade titanium, stainless steel, and gold abutments formed the control groups. Plastic abutments were cast in nickel-chromium, cobaltchromium and grade IV titanium. The abutment/implant interface was analyzed. Analysis of variance and Duncan's multiple range test revealed no significant difference in mean marginal microgap between premade gold and titanium abutments and between premade stainless steel and cast titanium abutments. Statistically significant differences (P , .001) were found among all other groups. Key Words: microgap, premade abutments, cast abutments, internal hex implant, screw loosening INTRODUCTION A dental implant system consists of an implant that is surgically implanted in the maxilla or mandible and an abutment that engages the implant. Depending on the specific system used, an abutment can include a mechanical connection mechanism within itself or can be clamped onto the implant by means of an abutment screw. The dental prosthesis is then fabricated over the abutment.1 The connection of the abutment to the restorative interface of the implant creates a space called a microgap. The vertical microgap between the implant and the abutment plays a crucial role in implant survival and prosthetic success. The microgap may be colonized by bacteria and cause inflammatory reaction in periimplant hard and soft tissue. 1 Department of Prosthodontics, Educare Institute of Dental Sciences, Malappuram, Kerala, India. 2 Department of Prosthodontics, Annoor Dental College, Moovatupuzha, Kerala, India. 3 Department of Prosthodontics, MES Dental College, Perinthalmanna, Kerala, India. 4 Department of Pedodontics, Government Dental College, Trivandrum, Kerala, India. * Corresponding author, e-mail: drjainij@gmail.com DOI: 10.1563/AAID-JOI-D-11-00163 An absolutely precise fit (passive fit) between the prosthesis framework and abutments has been advocated to avoid stress concentrations in the bone adjacent to the implants.2-4 From a mechanical engineering standpoint, discrepancies and microgaps between components are inevitable when different parts are fitted together.5 According to the current scientific evidence and the efficacy of contemporary dental technology used for framework fabrication, it has been concluded that an absolute passive fit cannot be obtained.6 If an absolute passive fit cannot be obtained between implant/abutment interfaces, this may lead to such prosthetic complications as loosening or fracture of the screws that retain the prosthesis to implant.7-11 Fracture of abutment screws is more prevalent than fracture of prosthesis-retaining screws.12-14 A clinical trial carried out by Jemt and Book15 could not find a statistically significant correlation between marginal bone level and prosthesis misfit. But when considering the mechanical aspect of the implant prosthesis, poor fitting prosthesis with 6 lm to 10 lm vertical misfit may lead to screw loosening.11,15 Previously, a few in vitro studies have reported on the marginal fit and size of microgaps at the implant abutment interface for external hex jointJournal of Oral Implantology 239

Table of Contents for the Digital Edition of Journal of Oral Implantology June 2014

Controlled Early Inflammation and Bone Healing—Potential New Treatments
Zygomatic Implants: The Impact of Zygoma Bone Support on Biomechanics
A Comparative Study on Microgap of Premade Abutments and Abutments Cast in Base Metal Alloys
Topical Simvastatin Improves the Pro-Angiogenic and Pro-Osteogenic Properties of Bioglass Putty in the Rat Calvaria Critical-Size Model
Assessment of the Correlation Between Insertion Torque and Resonance Frequency Analysis of Implants Placed in Bone Tissue of Different Densities
Benefits of Rehabilitation With Implants in Masticatory Function: Is Patient Perception of Change in Accordance With the Real Improvement?
A Method for Fabrication of Implant-Supported Fixed Partial Dentures
Safe Sinus Lift: Use of Acrylic Stone Trimmer to Avoid Sinus Lining Perforation
The Effects of Sinus Membrane Pathology on Bone Augmentation and Procedural Outcome Using Minimal Invasive Antral Membrane Balloon Elevation
Cellular Responses to Metal Ions Released From Implants
A Two-Stage Surgical Approach to the Treatment of Severe Peri-Implant Defect: A 30-Month Clinical Follow-Up Report
Eight-Year Follow-Up of a Fixed-Detachable Maxillary Prosthesis Utilizing an Attachment System: Clinical Protocol for Individuals With Skeletal Class III Malocclusions
Active Implant Peri-Apical Lesion: A Case Report Treated Via Guided Bone Regeneration With a 5-year Clinical and Radiographic Follow-up
Flapless Implant Placement: A Case Report
Active Implant Periapical Lesions Leading to Implant Failure: Two Case Reports
A Review of Platelet Derived Growth Factor Playing Pivotal Role in Bone Regeneration
LETTER TO THE EDITOR
REVIEW OF CURRENT LITERATURE

Journal of Oral Implantology June 2014