Journal of Oral Implantology February 2014 - (Page 37)

RESEARCH Stress Distribution Around Maxillary Anterior Implants as a Factor of Labial Bone Thickness and Occlusal Load Angles: A 3-Dimensional Finite Element Analysis Marzieh Alikhasi, DDS, MS1 Hakimeh Siadat, DDS, MS2 Allahyar Geramy, DDS, MS3 Ahmad Hassan-Ahangari, DDS, MS4* The purpose of this study was to evaluate the influence of the stress/strain distribution in buccal bone of an anterior maxillary implant using 3 bone thicknesses under 5 different loading angles. Different testing conditions incorporating 3 buccal bone thicknesses, 3 bone compositions, and 5 loading angles of an anterior maxillary implant were applied in order to investigate the resultant stress/strain distribution with finite element analysis. The maximum equivalent stress/strain increased with the decreasing of loading angle relative to the long axis. In addition to loading angle, bone quality and quantity also influenced resultant stress distribution. Dental practitioners should consider combinations of bone composition, diameter, and load angulations to predict success or failure for a given implant length and diameter. Key Words: dental implants, bone quality, biomechanics, finite element analysis, off-axis load INTRODUCTION T here are several biomechanical factors including type of loading, implant geometry, surface structure, quality and quantity of the surrounding bone, and the nature of the bone-implant interface that could affect stresses and strains around osseointegrated dental implants.1 The existing 3dimensional bone not only affects the ideal implant position but also influences the degree of bone remodeling following implant placement.2,3 Thick1 Dental Research Center and Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. 2 Dental Implant Research Center and Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. 3 Department of Orthodontics and Dental Research Center, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. 4 Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. * Corresponding author, e-mail: gueramya@tums.ac.ir DOI: 10.1563/AAID-JOI-D-10-00198 ness of the bone in the bucco-oral and mesiodistal of the implant is an important factor that affects resorption, which leads to soft-tissue shrinkage or edema.3 There is insufficient evidence to set a threshold for minimal buccal bone thickness to ensure an optimal esthetic outcome, although it has been suggested that it is crucial to have a buccal bone plate of at least 1 mm.4,5 Buser et al2 demonstrated several clinical guidelines regarding the correct implant positioning in relation to buccooral bone dimensions especially in the maxillary anterior zone. They have recommended that the bucco-oral bone thickness should be at least 2 mm around the implant.2 This buccal bone thickness was advocated to ensure proper soft-tissue support, avoid resorption of the facial bone wall following restoration, and minimize the risk for peri-implant soft-tissue recessions.6,7 Since the occlusal loads of maxillary anterior teeth are in the outward direction, this buccal bone has a special role in enduring the loads. When the load direction is not in the long axis of an implant, the buccal, lingual, and proximal Journal of Oral Implantology 37

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

Evolution of Bone Grafting for Improved Predictability
Electrochemical Behavior of Titanium in Artificial Saliva: Influence of pH
Efficacy of Antibacterial Sealing Gel and O-Ring to Prevent Microleakage at the Implant
Wired/Classic and Wireless/Periotest ‘‘M’’ Instruments: An In Vitro Assessment of
Altered Position of the Medial Lingual Nutritional Foramina at Different Stages of Alveolar
Genotoxicity of Endosseous Implants Using Two Cellular Lineages In Vitro
Implants With Internal Hexagon and Conical Implant-Abutment Connections: An In Vitro
Stress Distribution Around Maxillary Anterior Implants as a Factor of Labial Bone Thickness
Peri-Implant Biomechanical Responses to Standard, Short-Wide, and Mini Implants
Removal Torque Analysis of Implants in Rabbit Tibia After Topical Application of
Nonprocessed Adipose Tissue Graft in the Treatment of Peri-Implant Osseous Defects in
Assessment of the Effect of Two Occlusal Concepts for Implant-Supported Fixed
Nerve Damage Assessment Following Implant Placement in Human Cadaver Jaws:
Dental Implants: Early Versus Standard Two-Stage Loading (Animal Study)
Intravenous Sedation for Implant Surgery: Midazolam, Butorphanol, and
Nanocrystalline Hydroxyapatite-Based Material Already Contributes to Implant Stability
Two Neglected Biologic Risk Factors in Bone Grafting and Implantology: High Low-Density

Journal of Oral Implantology February 2014