Surface Modification of Dental Implants

and Experimental Study on

Commercially Pure Titanium(CP-Ti)

Surface

11065110 - İbrahim Ahsen Dikici

Advisor: Asst. Prof. Binnur SAĞBAŞ

Undergraduate ThesisPrepared in Materials Science and Manufacturing TechnologiesYıldız Technical University , Turkey – May 6th, 2016

Objectives

Background

Introduction

Materials and Methodology

Surface Modification and Characterization

Results & Discussions

Conclusions

Ou

tlin

e

Synthetic Biomaterials

metals

ceramics

polymersComposites

Introduction

Biomaterial is…

"any substance (other than drugs) or

combination of substances synthetic or

natural in origin, which can be used for

any period of time, as a whole or as a

part of a system which treats,

augments, or replaces any tissue, organ,

or function of the body".

Orthopedic screws/

fixation

Dental Implants

Skin/

cartilage

Drug Delivery

Devices

Ocular

implants

Heart valves

Bone replacements

Joint implants

Introduction and History

Dental implants are surgically

fixed substitutes for roots of

missing teeth. Embedded in the

jawbone, they act as anchors

for a replacement tooth, also

known as a crown, or a full set

of replacement teeth.

The Romans, Chinese, and Aztec

used gold in dentistry more than

2000 years ago..

The most widely accepted and successful dental

implant today is the osseointegrated implant,

discovered by Professor Per-Ingvar Brånemark in the 1950s

crown crown

gum

bone

root fixture

tooth implant

abutment

Background

Surface roughness

Chemical composition

Surface morphology &

Topography

Successful

implantation

Surface Modification

In order to accomplish biological integration, it is necessary to have

good bone formability. In applications, good wear and corrosion

resistance is also required. The proper surface modification techniques

not only retain the excellent bulk attributes of titanium and its alloys,

such as relatively low modulus, good fatigue strength, formability and

machinability, but also improve specific surface properties required by

different clinical applications.

Surface Modification

1. Mechanical Methods

1.1. Grit-blasted Surface

1.2. Laser Modified Micro- and Nano-Structered Surface

2. Chemical Methods

2.1. Chemical Treatment

Acid Treatment, Hydrogen Peroxide Treatment, Alkali Treatment

2.2. Sol–Gel Coatings

TiO2 Coatings, Calcium Phosphate Coatings,Titania/Hydroxyapatite Composite Coatings

2.3. Anodic Oxidation

2.4. Chemical Vapor Deposition

3. Physical Methods

3.1. Thermal Spraying

3.2. Physical Vapor Deposition

3.3. Glow Discharge Plasma Treatment

3.4. Ion Implantation and Deposition

Oxygen Implantation, Nitrogen Implantation, Carbon Implantation and Deposition, Metal Ion

Implantation

Surface Characterization

In order to achieve a desired biological response for implants in different medical applications various kinds of structural and chemical modifications have been developed.

It is now generally accepted that surface features at different length scales influence the integration.

Characterization of the topography by scanning electron microscopy (SEM), chemical composition and electrical properties were studied using X-ray diffraction (XRD), Xray photoelectron spectroscopy (XPS).

Samples Characterization

Surface Profilometer

XRDEDX

SEM

Objectives

Surface treatments and modification such as BCP grit blasting or acid etched and a combination of blasting and acid etching technique were applied to do selected dental implant samples.

In this experimental study, roughness specifications (e.g., Ra, Rq, Rz) values of all surfaces were measured with contact stylus profilometer device.

To achieve more accurate surfaces images, surface topographies were also investigated with scanning electron microscope(SEM).

Pro

ject

Ro

ad

Map

Project Start

Literature Study

Grit Blasting

Acid Etching

Grit Blasting+Acid Etching

Final Report

Project End

Project

BCP(HA%65 + b-TCP %35) grit-

blasted (particle size <300 µm

Output:Profilometer, SEM

Output:Profilometer, SEM

Output:Profilometer, SEM

(1% HF + 30%HNO3 for 60

min at room temperature)

Materials and Methodology

Titanium implants : cp-Ti grade 4Diameter:4.1mm, length: 11.5 mm

Titanium is biocompatible (non-toxic and is not rejected by the body) and has the inherent property to osseointegrate enabling use in dental implants that can remain in place untill the end of life.

Table Standard Specification for Unalloyed Titanium, for Surgical

Implant Applications(UNS R50700), ASTM F67 – 13

Materials - Grit Blasting

Granules size : 100-150 μm, 150-200 μm, 200-250 μm, and 250-325 μm

Hydroxyapatite

[Ca10(PO4)6(OH)2]

Bioactive, able to integrate in bone

structures and support bone

ingrowths, without breaking down or

dissolving . Generally applied as a

blasting materials

Grit Blasting

Air pressure: 4 Bar for 40 seconds

Materials - Acid Etching

Concentration: 1% HF + 30% HNO3

Duration: 60 Minutes at RT

Hydrofluoric Acid [HF]

Nitric Acid [HNO3]

a colorless and weak acid, higly corrosive, capable of dissolving many materials

a highly corrosive and toxic strong

acid, used for the production of

fertilizers, production of explosives,

etching and dissolution of metals

Acid Etching

HF/HNO3

Blasted

Ti

implants

Results & Discussion >

Results & Discussion >Surface Roughness

Number Ra Rz Rq

1 1,35 µm 9,1 µm 1,66 µm

2 1,26 µm 21,0 µm 1,97 µm

3 1,19 µm 6,7 µm 1,43 µm

4 0,46 µm 2,4 µm 0,54 µm

5 0,46 µm 2,6 µm 0,54 µm

6 0,60 µm 4,9 µm 0,80 µm

7 0,35 µm 1,8 µm 0,41 µm

8 0,31 µm 1,6 µm 0,36 µm

9 0,38 µm 3,3 µm 0,48 µm

10 1,65 µm 8,6 µm 1,95 µm

11 1,68 µm 12,4 µm 2,32 µm

12 1,41 µm 9,5 µm 1,73 µm

Surface Roughness Parameters

Results & Discussion >Surface Roughness

The BCP grit blasted surfaces were provided with Ra values in

the range of 1.41 - 1.65 µm, Ra values of BCP grit

blasted+acid etched surfaces in the range of 1.19 - 1.35 µm

while the only acid etched surfaces were of a reported range

of 0,46 - 0,60 µm. All of them had higher Ra values than the

as-machined surface roughness of 0.31 - 0.38 µm. The

HF/HNO3 treatment resulted in the embellishment of the

microrough BCP grit blasted surface with nano and

microtopographic features.

Tissue Implants different types of surfaces observed by scanning electron microscope(SEM) at 50x magnification

Machined+BCP grit blasted+acid etched surfaces Machined+acid etched surfaces

Machined surfaces Machined+BCP grit blasted surfaces

Results & Discussion >Surface Morphology

Surface MorphologyResults & Discussion >

Machined+BCP grit blasted+acid etched surfaces Machined+acid etched surfaces

Machined surfaces Machined+BCP grit blasted surfaces

Tissue Implants different types of surfaces observed by scanning electron microscope(SEM) at 5000x magnification

softer edges and

less observed

protruding

surfaces

sharp edges and

ridge occurring

white little

clusters

smooth areas

Conclusions

To conclude that rough-surfaced implants have significantly higher success rates compared with dental implants with smooth surfaces. Because roughness of the surface plays a predominant role in cell adhesion during the implant healing phases, this factor should be considered in the manufacturing of endosseous implants.

This study demonstrated major differences of the surface properties, according to the surface treatment used, i.e., BCP grit blasting or HF/HNO3 etched and a combination of blasting and acid etching technique for the implants.

The highest Ra value ranges was measured respectively on bcp grit blasted implant 1,41-1,68µm, BCP grit blasted+acid etched implant 1,19-1,35µm, acid etched implant 0,46-0,60µm and machined implant 0,31-0,38µm.

Despite the importance of roughness in osseointegration, there is no standart for the roughness of dental implants and other surface properties should also be considered important in the biologic response and may be more critical parameters of biocompatibility than surface roughness.

In addition to this study, in vivo studies with animal models are necessary for a better comparison of the osseointegrative properties of these four different surfaces.

Thank you…