Journal of Oral Implantology October 2013 - (Page 559)

RESEARCH In Situ Tooth Replica Custom Implant: A 3-Dimensional Finite Element Stress and Strain Analysis Wael Aly Ghuneim, BDS, DDS, MDS, PhD, DSc* This study is a phase of a biomechanical study, a part of a research program concerned with the new concept of in situ tooth replication. The purpose of the study was to evaluate tooth replica under each of two possible circumstances: (1) attachment via periodontal ligament and (2) osseointegration. Replicas were made of Cortoss, a bioactive glass, bone substitute. Three-dimensional finite element analysis was used to assess the stresses and strains resulting from each of 2 types of loads: off-vertical pressure and vertical point force acting on natural mandibular second premolar and corresponding replicas. Natural tooth tolerated 19 MPa pressure or 85 N vertical force, periodontally attached replica tolerated 15 MPa pressure or 80 N force, and osseointegrated replica tolerated 23 MPa pressure or 217 N force. Key Words: in situ, tooth replica dental implant, anatomic dental implant, immediate implant, custom implant, tooth substitute, Cortoss, 3D finite element INTRODUCTION I n a previous study, the author proposed the concept of in situ tooth replication.1 It is to restore a missed tooth to its anatomy, radicularly and coronally. The concept was motivated by the awareness of the importance of teeth anatomy and configurations that are allied to function.2–5 As a first part of the research program, the previous study focused on the technique of application and the prediction of the biologic acceptance of the suggested bioactive glass, bone substitute Cortoss. To the best of knowledge, it was the first reported attempt of such an initiative. Therefore, it is worth mentioning here some of the features of this relatively recent material and to review the proposed technique. Cortoss is a high degree of 3-dimensional, crosslinked resin that is reinforced by ceramic particles. The high molecular weight of the monomers (286–640 g/mol) is the causal of the high degree of conversion (76% to 86% experimentally and 95% theoretically) and indicates minimal leaching Dr Wael Dental Clinic, Cairo, Egypt. * Corresponding author, e-mail: ghuneim@tedata.net.eg DOI: 10.1563/AAID-JOI-D-10-00142 at body temperature and limited chemical trauma.6 The material is packaged sterile in a dual cartridge as a paste-paste system. It has a compressive strength of 146 6 18 MPa, a 4-point bending strength of 57 6 10 MPa, and a bending modulus of 5505 6 509 MPa.7 Cortoss has been described by being strong enough to bear the load of body weight,8 and hence, augmentation of load-bearing bones is one of its applications.9,10 It is also used in vertebral augmentation,11,12 cranioplasty,13,14 femoroplasty, 9 and screw augmentation.15,16 The material is classified as osteoconductive bioactive glass that induces osteosynthesis.17 Direct contact with host bone is achieved via a carbonated apatite bond.17 The pull-out strength is nearly 140 N after 6 and 12 weeks, 340 N after 24 weeks, and 900 N after 1 year.8 These values surpass the 500 g (’50 N) anchorage required for dental implants.3 The state of mutual clinical rigid attachment alongside histological direct bone contact is the basic definition of osseointegration.2,18,19 What’s more, periodontal ligaments have the ability to proliferate from their formative fibroblasts, regenerate, and attach to replanted teeth as well as to bioactive glass ceramics. 20–25 Therefore, if remnants of periodontal ligaments Journal of Oral Implantology 559

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

Food and Drug Administration: Reclassification of Blade Form Dental Implants
Optimizing Platelet-Rich Plasma Gel Formation by Varying Time and Gravitational Forces During Centrifugation
Effect of Surface Roughness and Low-Level Laser Therapy on Removal Torque of Implants Placed in Rat Femurs
Impression Techniques for Multiple Implants: A Photoelastic Analysis. Part I: Comparison of Three Direct Methods
Impression Techniques for Multiple Implants: A Photoelastic Analysis. Part II: Comparison of Four Acrylic Resins
A Pig Model for the Histomorphometric Evaluation of Hard Tissue Around Dental Implants
In Situ Tooth Replica Custom Implant: A 3-Dimensional Finite Element Stress and Strain Analysis
Influence of Different Soft Liners on Stress Distribution in Peri-Implant Bone Tissue During Healing Period. A 3D Finite Element Analysis
Influence of Surface Nano-Roughness on Osseointegration of Zirconia Implants in Rabbit Femur Heads Using Selective Infiltration Etching Technique
Modified Titanium Surfaces Alter Osteogenic Differentiation: A Comparative Microarray- Based Analysis of Human Mesenchymal Cell Response to Commercial Titanium Surfaces
Hemorrhage Secondary to Interforaminal Implant Surgery: Anatomical Considerations and Report of a Case
Rehabilitation of a Patient With Mandibular Resection Using Osteointegrated Implants: A Case Report
Two-Stage Bone Expansion Technique Using Spear-Shaped Implants Associated With Overlapped Flap: A Case Report
Implant Esthetic Restoration in Ridge Deficiencies in Cases of Trauma: A Case Report
Rehabilitation of the Atrophic Maxilla With Tilted Implants: Review of the Literature

Journal of Oral Implantology October 2013