Journal of Oral Implantology October 2014 - (Page 603)

RESEARCH LETTER Implant Placement With a Guided Surgery System Based on Stress Analyses Utilizing the Bone Density: A Clinical Case Report Masahiro Wada, DDS, PhD Takanori Andoh, DDS, PhD Tomoya Gonda, DDS, PhD Yoshinobu Maeda, DDS, PhD* INTRODUCTION W ith the help of 3D geometrical data from CT scanning as well as computer software for placement planning or provision, guided safe and precise implant placement has become possible based on the available bone volume. However, predictions of the initial implant stability and stress distribution through the implant after integration are also important. Since multislice CT (MSCT) data have not only geometrical information but also bone quality information based on Hounsfield units (CT value),1 it is theoretically possible to select an implant placement site with a high CT value to obtain good initial stability as well as create a 3D finite element model for deciding the length and diameter of an implant in relation to stress distribution in a given clinical case. The purpose of this pilot study was to examine the possibility of utilizing CT bone density data for predicting the initial implant stability and stress around integrated implants with an overdenture abutment using actual clinical data. METHOD AND RESULT The patient was a 62-year-old totally edentulous male seeking a mandibular implant overdenture for better stability and higher masticatory performance. Department of Prosthodontics and Oral Rehabilitation, Osaka University School of Dentistry, Osaka, Japan. * Corresponding author, e-mail: ymaeda@dent.osaka-u.ac.jp DOI: 10.1563/AAID-JOI-D-12-00194 After the initial diagnosis and provision of informed consent for both the treatment and this study, diagnostic maxillary and mandibular complete dentures were fabricated for MSCT scanning (Toshiba, Tokyo, Japan). The bone density information in the MSCT data for the mandible was analyzed with simulation software for implant placement site and direction (iCAT version 2, Osaka, Japan) where higher initial stability could be predicted based on the CT value. The actual initial implant stability was measured at its placement with a torque controller. The MSCT data were also used to construct a 3D finite element model using special software (Mechanical Finder-RCCM, Tokyo, Japan). Pairs of titanium implants with different diameters and lengths (1.8 3 10.0, 3.75 3 7.0, 3.75 3 10.0, 3.75 3 14.0, and 5.0 3 10.0 mm) as well as the mandibular complete denture and average soft tissue thickness data were also constructed. The material properties of the mandibular bone were determined using Keyak's equation.2 The material properties of the denture base and soft tissue were applied from a previous study.3 Analyses of the stress in the bone around the implants under 50 Ncm of load at the right first molar occlusal surface were carried out and evaluated for the cervical, middle, and tip areas of each implant. Bone density and implant placement site For the implant placement using the simulation software, the bone CT values were divided into five categories according to Misch's classification of bone quality.1 High CT value regions were observed on the surface cortical bone area and inside Journal of Oral Implantology 603

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

New AAIP Affiliates Increase JOI Readership
Letter to the Editor
Bone Response From a Dynamic Stimulus on a One-Piece and Multi-Piece Implant Abutment and Crown by Finite Element Analysis
Effect of Platelet-Rich Plasma on the Healing of Mandibular Defects Treated With Fresh Frozen Bone Allograft: A Radiographic Study in Dogs
Efficacy of Growth Factor in Promoting Early Osseointegration
Assessment of Candida Species Colonization and Denture-Related Stomatitis in Bar- and Locator-Retained Overdentures
A Simple Solution for Vector Control in Vertical Alveolar Distraction Osteogenesis
Maxillary Ridge Augmentation With Custom-Made CAD/CAM Scaffolds. A 1-Year Prospective Study on 10 Patients
A Retrospective 3- to 5-Year Study of the Reconstruction of Oral Function Using Implant- Supported Prostheses in Patients With Hypohidrotic Ectodermal Dysplasia
Effects of a New Implant Abutment Design on Peri-Implant Soft Tissues
Repair Technique for Fractured Implant-Supported Metal-Ceramic Restorations: A Clinical Report
Full-Mouth Rehabilitation for a Patient With Dentinogenesis Imperfecta: A Clinical Report
New Method to Increase Inter-alveolar Height With Preservation of Crestal Cortical Bone for Implant Treatment
Implant Placement With a Guided Surgery System Based on Stress Analyses Utilizing the Bone Density: A Clinical Case Report
A Novel Technique for Osteotome Internal Sinus Lifts With Simultaneous Placement of Tapered Implants to Improve Primary Stability
Maxillary Sinus Augmentation and Implant Placement Using Venous Blood Without Graft Material: A Case Letter
Modification of Maxillary Sinus Floor With Orthodontic Treatment and Implant Therapy: A Case Letter
A Surgical Guide for Optimal Placement and Immediate Restoration of Implant
Osseointegrated Dental Implants in Growing Children: A Literature Review

Journal of Oral Implantology October 2014