Prosthodontic applications of lasers in dental laboratory

1. prosthodontic applications of
lasers in dental laboratory
Sherif Sultan, BDS, MSc, PhD, Fixed10/21/2019 1

2. 1- laser optical laboratory scanners(
laser is used as a light source)
• laser scanner: is a 3D scanner measuring the distance
to an object surface by triangulation mechanism
• Most dental optical scanners are triangulation or
confocal scanners. In case of triangulation, a light
source, typically a laser, shines onto an object and its
reflection is captured by a sensor that is positioned
slightly off-angle to the angle of the incident light. As
the next laser beam is reflected by an adjacent location
at a different distance to the light source, it is recorded
in a different location on the sensor array. It is this
difference that is used to compute the difference in
distance to the original source, and by inference the
topography of the surface being scanned.
10/21/2019
Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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3. Components of any CAD/CAM systems
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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4. How a triangulation scanner works.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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5. • in case of confocal scanners, the device
consists of sensors that are preprogrammed
for a set distance that can register only light
reflected from that precise distance. The light
source here is red light not laser.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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6. 2- Resin polymerization of 3D printed
casts.
• Virtual casts may be generated from data
captured directly intraorally or by a scan of a
solid model of the dentition obtained through a
conventional impression technique in the dental
laboratory with a laboratory scanner.
• These digital data can be used to generate solid
working casts by an additive process in which
incremental layers of resin are
polymerized by a laser.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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7. CAM(computer aided manufacturing
• CAM refers to the use of computer software to program
the machinery that is responsible for the milling or
printing of intermediate and final restorations.
• CAM is separate from the actual design of restorations—it
is the communication between the CAD software and the
milling units. This involves the selection of where on the
block of material a crown should be milled, how thick the
layers of wax should be during wax printing, and so on.
• CAM manufacturing techniques are:-
• subtractive.
• Additive.
• Combination(subtractive then additive).
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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8.  Additive
manufacturing
includes:-
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• 3D Printing .
• laser sintering or
laser melting.
• Rapid prototyping
• Layered
manufacturing
• Stereo-lithography

9. 3-New Technologies for Base Metal Alloys
(laser deposition or LENS technology)
• Optomec (http://www.optomec.com) developed laser deposition, or
LENS (laser-engineered net shaping), technology in which a high-power
laser in an argon environment is used for melting elemental or alloy
powders, which are directed onto a small area of a substrate through
special nozzles to build up, layer by layer, a complex part in a raster
(horizontal lines)pattern.
• This technique enables functionally graded titanium alloy compositions
to be created with controlled microstructures and mechanical
properties for orthopedic applications. However,
further development of the LENS system is needed for clinical usage in
prosthodontics, because dental restorations are much smaller than
orthopedic implants.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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10. Definitions
• Selective laser melting: SLM; an additive CAM continuous
layering buildup process in which elemental metal or alloy
powder deposition is closely followed by laser melting to
create a finished shape under computer control.
• Selective laser sintering: SLS; an additive CAM technique by
sintering plastics, glass, or ceramics into 3D structures.
• generally sintering means densification.
• But in PFM RESTORATIONS, Sintering is the process of firing
the compacted ceramic powder at high temperature to
ensure optimal densification. This occurs by pore
elimination and viscous flow when the firing temperature is
reached.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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11. • In laser sintering/melting dental technology, developed
by several companies (BEGO, Phenix Systems and
Heraeus Kulzer), a high power laser is used to
selectively fuse particles lying on a powder bed and
build a complex part layer by layer.
• This is used with Biocompatible Co-Cr alloys, titanium
and a gold-platinum alloys.
• As a result of further developments in laser sintering,
this technology may replace the dental casting
technology that has served the profession well for the
past century.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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4- Metal 3D printing

12. 5- Laser sintering of dry milled partially
sintered Co-Cr alloy blanks
• Amann Girrbach (well known dental
manufacturing company, AG) introduced Ceramill
Sintron partially sintered Co-Cr alloy blanks that
can be readily dry-milled by means of a milling
machine and subsequently final sintered in a
special furnace with an argon atmosphere.
• Both the milling machine and the furnace can be
obtained from the manufacturer, which claims
that the process yields restorations and
frameworks with homogeneous and distortion-
free structures.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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13. 6- Laser Welding (e.g:- laser star and I -
weld laser welding devices
• Laser welding is the joining of metal components through the
use of heat generated with a laser beam.
• Laser assembly of FDPs has been reported to have higher
strength and reduced corrosion in comparison with
conventional soldering, although laser-welded connectors
seem as susceptible to fatigue failure and may be less suitable
for joining noble-metal alloys than for base-metal alloys. Laser
welding is a practical way to join cast or milled titanium or
cobalt-chromium components (i.e., if these are to be used for
implant-supported prosthesis frameworks).
• RIGID CONNECTORS, Rigid connections in metal can be made
by casting, milling, laser sintering, soldering, or welding.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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14. • Manual laser welding systems are an essential tool for today's
modern dental laboratory. An excellent alternative to
conventional soldering procedures, manual laser welding
systems assist dental laboratory technicians in fabrication and
reconstructive repair procedures, including new cast clasp
assembly, loops and posts for tooth additions, cast extensions
for existing partials, new wrought wire single-arm clasping, as
well as many other common laboratory welding services. The
state-of-the-art, free-moving concept allows operators to
benefit from pin-point accuracy and localized heat, which
produces excellent seam welds and eliminates thermal
expansion on passive fit bridgework, implant bars and frames,
and other common dental prosthetic connections. E.g:-
LaserStar welding systems are suitable for most dental alloys
including titanium.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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15. Laser welding. Individual titanium components are carefully aligned in the
laser welding unit. The joining procedure is monitored with high
magnification video.
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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16. Laser welding applications
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1. Welding connector
1. Extending a margin

17. • 3- welding implants
• 4- repairing porosity
• or hole in a crown
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Sherif Sultan, BDS,MSc,PhD,Fixed
Prothodontics
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