3d printing technology and its modalities

1. Presented by,
Sai Bharath
3D PRINTING IN
PROSTHODONTICS
“what we see is what we get”

2. Contents
• Introduction
• History
• Synonyms
• Definition
• Principle
• 3D Printing technology
• 3D printing over CAD CAM technology
• 3D Printing Process
• 3D Printing Modalities and materials
• Use of 3D printing in Prosthodontics
• Conclusion
• References

3. Introduction
• Technological developments have made significant impact and
contributions to the field of dentistry.
• Impression followed by laboratory processing of the restoration.
This procedure involves several steps which increases the possibility
of errors in marginal accuracy, time consumed by the patient as well
as the doctor and the treatment costs.
• Advances in computer technology now en- able cost-effective
production of individual pieces.

4. • 3D printing generally describes a manufacturing process that creates
an object by building one layer at a time adding multiple layers which
results in the formation of an object.
• 3D printing can be precisely described as Additive manufacturing or
Rapid prototyping.
• 3D Printing is emerging as a promising technology over a wide
variety of fields including aerospace, defence, art, design,
architecture, engineering, medicine, dentistry by allowing the
individuals to personalise designs and fabricating .
• 3D printing promises to improve patient care.
• In dental field it has been used in various treatment modalities.

5. History
• In 1984, Charles Hull an American Engineer, developed the
world’s first working 3-D printer.
• Hull later founded the company 3D Systems which
introduced the first commercially available 3D printer named
SLA-250 in 1988.
• Organovo ,a regenerative medicine company released data
on the first fully bio printed blood vessels and highlighted
on bio printing technology in 2010 .

6. Synonyms
•3D printing is also known as :
 Additive manufacturing ,
 Rapid prototyping,
 Layered manufacturing ,
 Solid free form fabrication

7. Definition
• The term 3D printing is generally used to describe a manufacturing
approach that builds objects one layer at a time, adding multiple layers
to form an object - American Society for Testing and Materials
(ASTM)

8. Principle
The process of additive manufacturing works on the principle
Taking a 3D computer file and creating a series of cross-sectional slices
Each slice is printed one on top of other to create the 3 D object
with an advantage of minimal wastage

9. 3D printing technology
• From a mechanical perspective, 3D printers are often quite simple robotic
devices
• The apparatus would be nothing without the computer-aided design (CAD)
software that allows objects, and indeed whole assemblies to be designed in a
virtual environment
• For 3D printing to have value we need
1. Objects to print
2. CAD software which allows us to create objects from scratch
• But in dentistry we also need
3. Volumetric data in the form of
-computed tomography (CT) data
- Cone beam computed tomography (CBCT) data
- Intraoral or laboratory optical surface scan data

10. 3D printing over CAD CAM technology
1.Subtractive methods such as CAD CAM has some limitations in relation with
3 D printing.
2. Large amount of raw material is wasted because of unused portions of the
mono-blocks which are discarded after milling and recycling of the excess
ceramic is also not feasible.
3. Milling tools are prone to heavy abrasion and wear which shortens their
cycling time.
4. Due to brittle nature of ceramic microscopic cracks can be introduced during
the process of machining

11. 1
APPARATUS FOR 3D PRINTING

12. 3D Printing Process

13. 3D Printing Software

14. 3D Slicing

15. Mechanism
 It all starts with creation of a virtual design(CAD) of the object.
 The most common and universal file formats for 3D
printing are STL andVRML.
 Scanner may be used to produce a 3D model.
 The 3D model is sliced and then it is ready to feed into the 3D
printer of compatible brand and type.
 The 3D printer reads every slice (2D image) and creates a three-
dimensional object.

16. Modalities for 3D Printing
1. Stereolithography( SLA)
• 1980 by Charles Hull
• Principle of making solid objects involves successive printing of thin
layers of UV curable photopolymer layer by layer.
• Material used-light sensitive polymer

18. Advantages:
• Stereolithography include high accuracy, good surface finish, high
mechanical strength and smooth surface finish.
• Rapid fabrication
• Able to create complex shapes with high feature resolution
• Lower cost materials if used in bulk.
Disadvantage:
• The cost of the equipment, requirement for post-cure and it can be only
used for polymers
• scarcity of biocompatible resins with proper SLA processing
• use of photo initiators and radicals which may be cytotoxic
• Only available with light curable liquid polymers
• Inability to create compositional gradients along horizontal planes

19. 2. Fused Deposition Modelling
• Developed by Schott Crump
• A thermoplastic filament material is extruded through a nozzle controlled by
temperature and the material hardens immediately (within .1 sec) after
extrusion.
• Materials such as acrylonitrile butadiene styrene, polycarbonates and poly
sulfones are used.
• Fused Deposition Modelling requires support structures to be removed and can
be used with thermoplastic material only. It has a rough surface finish and does
not have hundred percent density

21. ADVANTAGE
• Variable mechanical strength
• low –to mid range cost material and equipment.
DISADVANTAGE
• Low cost but Limited materials - only thermoplastics.
• Limited shape complexity for biological materials.
• Support material must be removed.

22. 3. Selective Laser Sintering
• 1980 by university of Texas
• In this method a high power laser is directed using mirror at a substrate
consisting of fine layer of powder, when the beam hits the powder it forms a
melt pool and powder particles fuse together.
• After scanning of each cross-section the powder bed is lowered by one layer
thickness and a new layer of material is applied on top. This process continues
until the object is completed.
• Materials used – polymers (nylon) – SLS
• Metals and metal alloys (co-cr) - SLM

24. Advantage-
• ease of autoclavability of the materials used.
• lower cost materials
Disadvantage-
• powders are messy with increased inhalation risk.
• technology is expensive

25. 4. Photopolymer Jetting
• Inkjet printers jet ink onto paper and is allowed to dry, similarly material
jetting 3D printers jet micro droplets of liquid photopolymer resin onto a build
tray and polymerise it with UV light.
• It has a gel like material as a support system which is used during production
and this supporting material can be easily eliminated using water instantly after
the printing is finished.
• It is relatively simple and can be used immediately after printing without the
need to wait for a final cure

27. Advantage
• Relatively fast. High-resolution, high-quality finish possible.
• Multiple materials available various colours and physical properties
including elastic materials.
Disadvantage
• tenacious support material can be difficult to remove completely
• support material may cause skin irritation
• cannot be heat sterilised,
• materials cost is high

28. 5. Powder Binder Printer.
• This apparatus uses a modified inkjet head to print
• Liquid droplets are made to infiltrate a uniform and single layer of powder one
after the other incrementally and a final model is ready
Advantages
• machines and materials are lower cost
Disadvantages
• Low resolution
• messy powder
• Low strength
• difficult to heat sterilize

29. Use of 3D printing in Prosthodontics
1. Dental models 2. Fabrication of Denture

30. REMOVABLE PARTIAL DENTURE
FIXED PARTIAL DENTURE

31. Maxillofacial prosthesis

32. • Bibb et all conducted a study to assess the effectiveness of a method
which combined CAD and 3D Printing using Selective laser melting
method (SLM).
• A 3D scan of the partially edentulous patient cast was performed which
subsequently allowed the digital designing of the RPDs components.
• In the first experiment stainless steel was chosen because of its excellent
corrosion resistance making it suitable for dental application and in the
second experiment cobalt chromium alloy was selected.
• Using Selective laser melting a same RPD framework design was
printed using 2 different metals for comparative purpose.

33. • On comparing both the RPD frameworks, both showed accurate fit
on the patients cast, but the retentive component(clasp) of the
stainless-steel framework showed deformation after repeated insertion
and removal.
• The cobalt chromium alloy framework exhibited perfect fit on the cast
and patient with no signs of deformation.
• Thus Cobalt-Chromium alloy framework proved to be more efficient
than stainless steel. Compared to manual investment and casting
procedures, time taken for preparation, and probability for errors this
study shows result in favour of using 3D printing to construct RPD
frameworks

35. • Silva et al in a review article discussed the utilisation of the method of
“ROBOCASTING” to fabricate fixed partial dentures.
• Robocasting is a 3D printing fabrication method in which an object is
printed in a layer by layer fashion onto a flat substrate directly from
digital file.
• The paste used in robocasting is composed of ceramic part and
typically 47% solid and 1-2 % organic material. This paste is capable
of producing fine filaments and drying with minimal shrinkage

36. • Ebert et al conducted a study with an aim to develop a customised
direct inkjet printing process which can be used to build up high
strength zirconia ceramic prosthetic restorations.
• A customised additive system was developed which allowed printing
of suspension of high solid content of zirconia powder by combining
direct inkjet printing technology with conventional drop on demand
inkjet print heads.
• They tested that it is possible to overcome the major issues of
CAD/CAM milling system limited accuracy, wastage of raw materials
and possible occurrence of microscopic cracks by the direct inkjet
printing technology.
• The study concluded that it is capable of producing crown with
required size, shape and morphological features

38. • Dental Implants Surgical Guides

39. Guided Implant Surgery
 The first step in guided implant surgery is to run a cone beam scan on
the patient, which provides a wealth of information on the bone, bone
density, soft tissue, location and nerves.
 The DICOM file, or rendering of the patient’s anatomy, is
integrated into a guided surgery software program.
 There, the clinician and/or dental technician can virtually place an
implant and run a series of tests to ensure its best location outcomes.
 An impression of the patient’s mouth is captured, either digitally with
an intraoral scanner or with the analog PVS method, from which a
model is created and scanned.

41.  This creates an optical scan that provides an STL file that can quickly and
simply be overlaid onto the DICOM (cone beam) file and provide a
comprehensive STL file to be imported in to the guided surgery software.
 The clinician chooses the type of implant system and the implant size.

44. Conclusion
• There is huge impact of 3D imaging and modelling, and CAD
technologies on all aspects of dentistry.
• With the help of digital data it is possible to make accurate, precise
and complex geometrical forms in a variety of materials, locally or in
industrial centres through 3-dimensional printing.

45. References
1. 3d printing: the future technology in prosthodontics, by Dr.Sivaranjani Gali ,
Journal of Dental & Oro-facial Research Vol 11, Issue 1. Jan-Jun 2015
2. Recent Trends of 3-D Printing in Dentistry- A review, by Reeta Jain et al,
Annals of Prosthodontics & Restorative Dentistry, October-December
2016:2(4):101-104
3. 3D printing in dentistry by A. Dawood et al, BRITISH DENTAL JOURNAL
VOLUME 219 NO. 11 DEC 11 2015
4. Recent Trends of 3-D Printing in Dentistry- A review, by Reeta Jain et al,
Annals of Prosthodontics & Restorative Dentistry, October-December
2016:2(4):101-104
5. Applications of 3D Printing in Dentistry – A Review Abarna Jawahar1 ,
G.Maragathavalli

46. Thank You