Advanced manufacturing and related technologies in dentistry Flashcards Preview

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Flashcards in Advanced manufacturing and related technologies in dentistry Deck (31)
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1

Manufacturing techniques (3_

Conventional methods:
Impression techniques
-cheap
-easy to use
-high skills
-subjective
Subtractive - milling
-'low' investment
-simple shapes
New methods:
Additive - rapid prototyping
-complex shapes
-translucent
-materials
-training

2

What i CAD/ CAM? (3)

1. Data acquisition
2. Data processing
3. Manfacturing

3

Data acquisition (6)

Data acquisition for the existing structure of
interest.
• Computerised tomography (CT)
• Magnetic resonance imaging (MRI)
• Laser digitalising
• Ultrasound
• Mammography
• Conventional X-ray

4

Computerised tomography (2)

Radiographic technique for producing cross-sectional images by scanning a
slice of tissue form multiple directions using an arrow fan-X-ray

5

Magnetic resonance imagine (2)

Images obtained based on different tissue characteristics by varying the
number and sequence of pulsed radio frequency fields in order to take
advantage of magnetic relaxation properties of the tissues

6

Laser surface digitalising (LSD) (3)

A diode–based laser beam is split into a plane of laser light that comes out of the probe and shines below on the surface of the object being scanned. Thus a profile on the surface of the part is formed.

=intra-oral scanners!

7

Intra-oral scanners - pros and cons (7)

Pros:
-pt comfort
-dentist auto evaluation
-reduced model time
-favours clinic-lab communication
Cons:
-cost investment (coating)
-training
-just surface registration

8

Current literature lacks of sufficient evidence to
provide solid information regarding the use of
intraoral scanners under clinical conditions (3)

 For example, in 2017 only 4 published studies reported on
validity, repeatability and reproducibility of digital
measurements.
 Current reviews highlight the scientific evidence collected
on intraoral scanning is neither exhaustive, nor updated.
 Not all the commercially available scanners have been
tested in the clinical setting

9

Data processing (3)

Segmentation: selection of the regions of interest
Interpolation: to increase the resolution of the contour
CAD package: further manipulation of the files obtained

10

Segmentation (2)

Identifying and dividing the images into areas of
interest
• Often different organs
• Or sections of organs
Automated processes exist
• Not always accurate

11

Specialised CAD packages (2)

Materialise
 Specifically designed/ highly
specialised
 Expensive

12

General CAD packages (3)

Solidworks/ AutoCAD/ Blend
er
 Lots of learning resources
 Multiple applications
 Varying prices

13

Subtractive vs additive manufacturing (2)

Subtractive Manufacturing: controlled material-removal process (Machining)
Additive Manufacturing: builds objects by adding parts together in layers

14

Rapid prototyping techniques (layer-by-layer techniques (3)

• Stereolithography
• Fused deposition modeling
• Laser powder forming technique

15

Stereolithography (2)

• Additive fabrication process based on the spatially
controlled solidification of a liquid resin by
photopolymerisation.
• Cure depth given by the energy of the light to which the resin is exposed

16

Stereolithography: available materials (6)

WATERSHED
Medical prototyping USP
grade VI approved
XTREM
Very tough
Functional testing
Si25
Snap fits, concept models
and functional assembly
components
Si60
Production of prototype
models requiring some
level of transparency
BLUESTONE
Water handling
components
High temperature
applications
CERAMAX
Ceramic based material
Aesthetic and
functional components

17

Fused deposition (3)

• Non laser-based process that builds physical models by depositing layers of thermoplastic material
• No post-polymerisation needed
• Support material dissolved after model completion

18

Fused deposition steps (4)

Material feeding --> model fabrication --> support material removal --> final model

19

Fused deposition - available materials (5)

ABS
Strong, functional, smooth
parts with good feature detail
NYLON
Higher elongation at break
Good impact strength
PC
Accurate, durable, strong,
stable
Functional testing; imaging &
RF transparent
ABS-M30i
Bio-compatible (ISO 10993;
USP Class VI)
Gamma & EtO sterilizable
PC-ISO
Bio-compatible (ISO 10993; USP
Class VI)
Gamma & EtO sterilizable
Imaging & RF transparent
Strong and rigid

20

Laser powder forming technique (3)

• A high power laser is directed to a fine layer of powder
substrate using mirrors. The beam creates a melt pool
and the powder particles melt together
• Can produce parts from a relatively wide range of
commercially available powders
• Self-supporting method that allows the parts to be
nested together

21

Laser powder forming steps (4)

Material feeding --> model fabrication --> removal from the base --> final product

22

Laser powder based technique: available materials (5)

POLYMERS
Polyamide
Nylon
Polyethilene
COMPOSITES
Mixtures of polymers
Polymers and
hydroxyapatite
CASTING WAX
METALS
Steel
Ti and Ti-alloys
Co/Cr alloys
CERAMICS

23

Medical modelling (4)

• Study model
• Pre-plan surgery
• Practice surgery
• Especially useful
is unusual
anatomy

24

Drilling and cutting guides (3)

• Allow for highly
accurate
surgery
• Increases speed
and confidence
of placement
• Based on CT
scan

25

Partial denture frameworks (3)

• Mill or print crown
or bridge
copings/structures
• Wax burnout or
straight to metal
• Post-processing
required (printing)

26

Digital orthodontics (4)

• Based of CT data
• Software
predicts/plans
route
• Print out models
• Design/ plan
metal work

27

Dental/ craniofacial implants (3)

• Produce complex
geometry
• Porous/rough
surface
• Specific to patient

28

Additive manufacturing: current applications in dentistry (3)

SLM
-3D printed cobalt chrome
-crowns' bridges
-partial dentures

29

BUT……ARE ALL THE INNOVATIVE
APPROACHES AND COMPANIES
GOING FOR ADDITIVE? (2)

Not really
Some new companies are still milling e.g. Juvora
-cheaper

30

Additive manufacturing and the dental community (4)

• “Competition” with traditional manufacturing in creating end-use materials
• Transformation of the highly skilled labour// INVESTMENT
• High number of complex products made simultaneously
• Complex shapes at “affordable prices” with little waste
material