Journal of Oral Implantology June 2014 - (Page 231)

RESEARCH Zygomatic Implants: The Impact of Zygoma Bone Support on Biomechanics Shihab A. Romeed, PhD, MSc, DDS1* Raheel Malik, BSc, BDS2 Stephen M. Dunne, PhD, BDS1 Maxillectomy and severely resorbed maxilla are challenging to restore with provision of removable prostheses. Dental implants are essential to restore esthetics and function and subsequently quality of life in such group of patients. Zygomatic implants reduce the complications associated with bone grafting procedures and simplify the rehabilitation of atrophic maxilla and maxillectomy. The purpose of this study was to compare, by means of 3-dimensional finite element analysis, the impact of different zygomatic bone support (10, 15, and 20 mm) on the biomechanics of zygomatic implants. Results indicated that maximum stresses within the fixture were increased by 3 times when bone support decreased from 20 to 10 mm and were concentrated at the fixture/ bone interface. However, stresses within the abutment screw and the abutment itself were not significantly different regardless of the bone support level. Supporting bone at 10 mm sustained double the stresses of 15 and 20 mm. Fixture's deflection was decreased by 2 to 3 times when bone support level increased to 15 mm and 20 mm, respectively. It was concluded that zygomatic bone support should not be less than 15 mm, and abutment screw is not at risk of fracture regardless of the zygomatic bone support. Key Words: zygomatic implants, biomechanics, stress analysis INTRODUCTION D ental implants have been used clinically since 1965 to restore edentulous spaces. Their success is based on osseointegration, which is limited by the amount of bone available to support and anchor the titanium fixture.1 Thus, one of the challenges in implant dentistry is the restoration of severely resorbed or atrophic bone ridges. Early tooth loss, periodontal disease, trauma, tumor resection, and pneumatization of the sinus are causative factors for atrophy of the maxillary bone leading to insufficient volume, height, and width, thereby preventing successful osseointegra1 Deptartment Restorative Dentistry, King's College London Dental Institute, London, UK. Guy's Hospital, London, UK. * Corresponding author, e-mail: shihab.romeed@kcl.ac.uk DOI: 10.1563/AAID-JOI-D-11-00245 2 tion of implants without prior bone augmentation/ graft procedures.2,3 Bone augmentation is commonly used to increase bone volume prior to implant placement. However, these procedures are not without complications; they require invasive surgical intervention leading to patient morbidity, prolonged treatment time, and increased costs. To provide an alternative to such procedures, an extended length screw-shaped implant was developed and became known as the zygomatic implant.2 A zygomatic implant rather than being fixed into the alveolar bone is inserted through the palatal aspect of the residual alveolar bone in the posterior maxilla region, through the maxillary sinus and into the body of the zygomatic bone without the need for bone augmentation.3 This has many advantages, such as shortened treatment time and less patient morbidity, allowing the rehabilitation of the patient to improve mastication, speech and esthetics and overall improving the quality of life. There are a few different sizes for the zygomatic implant, varying Journal of Oral Implantology 231

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