Dissertation Defense – Deniz Mansouri (PHDME)

Deniz Mansouri– Ph.D. in Mechanical Engineering

Assoc. Prof. Polat Şendur – Advisor

Assoc. Prof. Özkan Bebek – Co-advisor

Date: 16.06.2025

Time: 12.00

Location: AB1 414

“Ultrasonic Vibration-Assisted Drilling Methods in Dental Implant Procedures: A Comparative Study on Reducing Force and Thermal Effects”

Assoc. Prof. Polat Şendur, Özyeğin University

Professor G. Guven Yapıcı, Özyeğin University

Assoc. Prof. R. Barkan Uğurlu, Özyeğin University

Assoc. Prof. Bekir Bediz, Sabanci University

Asst. Prof. Ali Tatar, Istanbul Technical University

Abstract:

Dental implants are recognized as an effective and reliable solution for tooth replacement, offering the dual benefits of restoring functionality and aesthetics while stimulating bone growth and preventing bone loss. However, the surgical drilling process required for implant placement poses significant challenges, particularly in preserving the structural integrity of the bone. Conventional drilling (CD) techniques, while widely used, often generate high thrust forces, torque, and elevated temperatures. These mechanical and thermal stresses can lead to adverse outcomes, including bone microdamage, thermal necrosis, prolonged healing times, and reduced implant stability, which may compromise the overall success of the procedure.

In recent developments, ultrasonically-assisted drilling (UAD) has emerged as a promising alternative, demonstrating potential in reducing drilling forces and minimizing thermal effects. By incorporating high-frequency vibrations into the drilling process, UAD decreases the continuous contact between the drill bit and the bone. This results in lower thrust forces, enhanced cutting efficiency, and reduced heat generation. These features suggest that UAD could address the limitations of CD and improve patient outcomes. Nevertheless, the application of UAD in dental implantology remains underexplored, particularly concerning its effects on the mechanical and thermal behaviors of jawbone tissues.

This study investigates and compares the mechanical and thermal behaviors associated with CD and UAD in dental drilling applications. To achieve this, a combination of finite element method (FEM) simulations and experimental analyses was used to evaluate critical parameters such as thrust force and temperature during drilling. The FEM simulations were designed to closely mimic realistic surgical scenarios by incorporating variables such as rotational speed, drill bit geometry, bone material properties, and vibration parameters. Experimental data were used to validate the FEM results, ensuring their accuracy and clinical relevance.

The findings from this study provide valuable insights into the potential of UAD as a dental drilling technique, which could influence future practices and contribute to safer and more effective implant procedures. The results indicate that UAD reduces thrust forces by approximately 30–35% compared to CD, with forces decreasing from about 65 N to 42 N under optimized conditions. Furthermore, UAD minimizes thermal effects, reducing maximum drilling temperatures by 25–30%, with peak temperatures falling from 52°C to 38°C. These reductions are essential for preserving bone integrity, as evidenced by a 40% decrease in microcrack formation compared to CD. The observed reductions in thermal and mechanical stresses with UAD are expected to enhance osseointegration, the process by which bone tissue integrates with the implant, leading to shorter recovery times and improved long-term stability of dental implants.

It is hypothesized that UAD will result in lower drilling forces and reduced thermal stresses compared to CD, facilitating less traumatic and more controlled bone removal. This research provides a comprehensive evaluation of the mechanical and thermal effects of UAD in dental applications, addressing a critical gap in the existing literature. Moreover, the study contributes to optimizing UAD parameters, including vibration frequency and amplitude, specifically tailored for dental implantology. By integrating experimental findings with simulation results, this work offers valuable guidelines for implementing UAD in clinical practice, paving the way for safer, more efficient, and patient-centered surgical procedures.

Bio:

Deniz Mansouri received his B.Sc. degree in Mechanical Engineering from University of Mohaghegh Ardabili in 2011 (Ardabil, Iran). He obtained his M.Sc. degree in Mechanical Engineering from Tabriz University in 2015 (Tabriz, Iran), where his research focused on Applied design and Fatigue Characteristics. He is currently working as a CAE Engineer at Mercedes-Benz Türk (Daimler Trucks), while pursuing the Ph.D. degree in Mechanical Engineering at the Vibration and Acoustics Laboratory (VAL) at Özyeğin University.

His research interests include vibration-assisted drilling (UAD), NVH (Noise, Vibration, and Harshness) analysis, finite element modeling, damping treatments, and dynamic topology optimization for vehicle and medical applications.