surface & subsurface damage in ceramic restorations - in

Ling Yin

Presented at the Department of Engineering Research Forum

June 6, 2007 ANU, Canberra

Surface & Subsurface Damage in Ceramic Restorations - In Vitro Study & Numerical Modeling

Intra-oral Conditions

Applied Load Ranges

Mastication 6 – 130 NMaximum 200 – 800 N

Cycles/day 1000 – 1400

Temperature Range 65°C

PH range 0.5 – 8.0

J R Kelly, Annu Rev Mater Sci 1997, 27, 443.

Why BioceramicsAestheticsBiocompatibilityChemical Durability

RequirementsEase of fabricationSufficient mechanical & corrosion resistance durabilityAppropriate aesthetic appeal

Restorative Processes for Dental Ceramics

Dental CeramicsAesthetics

BiocompatibilityChemical Durability

Dental CAD/CAMData Acquisition

Modeling & DesignCNC Machining

Handpiece FinishingMatching & Fitting

Surface IntegrityReplacement

Performance FatigueWear

Longevity

L Yin, X Song, Y Song, T Huang, J Li, Int J Machine Tool Manufact 2006, 46, 1013.

Dental Bioceramics Enamel MGC-C MGC-M MGC-Fine Macor Dicor Porcelain Empress 1Empress 2 Alumina Zirconia

Har

dnes

s (G

Pa)

0

2

4

6

8

10

12

14

16

Machinable Bioceramics

Difficult-to-Machine Bioceramics

L Yin, X Song, Y Song, T Huang, J Li, Int J Machine Tool Manufact 2006, 46, 1013.

Dental Bioceramics & Machinability

Tooth Feature-Based Posterior Crown DesignMesiodistal

Ridge

Dental Cusp

Dental Fossas

Ridge

Marginal Ridge

Grooves

Buccal Surface

Lingual Surface

Distal Surface

Mesial Surface

Central Groove

Marginal Ridge

Dental Cusp

Groove

Groove

Facio-lingual

(a)

Faciolingual Size

Bulge

Contact Area

Ridge

Contour

Distal Surface

Mesial Surface

Occlusal Surface

Cervico-occlusal

(b)

CervicalMargin

Length

Width

Feature of the Lower First Molar (J. B. Woelfel 1990)

(a) (b)

Scanned Points

Feature Points

Initial Data Points

Feature Point

Profile Feature Curve of Contour(a) (b)

Y Song, J Li, L Yin, T Huang, P Gao, Int J Adv Manufact Technol 2007, 31, 1058.

Intraoral Resurfacing Using Dental Handpieces

JADA

JADAhttp://www.ceramco.com/prod_cerconz_aacd.shtml

2-DOF Tester for In Vitro Dental Resurfacing

L Yin, X Song, S Qu, T Huang, J Mei, Z Yang, J Li, IMechE/H J Eng Med 2006, 220, 929.

In Vitro Dental Resurfacing Testing

L Yin, Y Han, X Song, H Wang, J Li, J Biomed Mater Res B, 2007, in press.

Surface Damage

L Yin, X Song, S Qu, Y Han, H Wang, J Biomed Mater Res 2006, 79B, 365.

(a) (b)

(c) (d)

Fracture

Smooth

Smeared

DebrisFracture

SmoothSmeared

Debris

Fracture

Smooth

Smeared

Debris

Fracture

Smooth

Smeared

Debris

Subsurface Damage

X Song, L Yin, Y Han, J Li, J Biomed Mater Res 2007, 79B, accepted.

FEA Modeling

X Song, L Yin, Y Han, J Li, J Biomed Mater Res 2007, 79B, accepted.

Summary 1. Computer-aided tooth feature-based posterior crown design

was developed. 2. A computer-assisted in vitro dental resurfacing apparatus

with 2-DOF was built, which enables the performance of precision-movement control of the dental handpiece and in-process measurement of force-related signals.

3. In vitro study of surface and subsurface damage was conducted, together with other intraoral resurfacing characteristics including handpiece rotational speed, force, torque, and energy.

4. FEA was applied for evaluation of stress distribution and for prediction of subsurface damage degrees.