Walsh, Laurence J.

University of Queensland eSpace

106 Australasian Dental Practice September/October 2008
high tech | DENTISTRY
L asers in the erbium family (Er:YAG andEr,Cr:YSGG) have a diverse range of hard and soft tissue applications in 
dentistry (Table 1). The soft tissue applications
have long been recognized in medicine, 
where these lasers have been used for resurfacing
skin, for middle ear surgery (stapedectomy) 
and for corneal modification for vision correction
for many years. The scope of soft tissue applica-
tions in dentistry is also broad, since these 
lasers can be used in many soft tissue procedures,
except in patients with bleeding disorders
where a long pulse duration is necessary to 
ensure haemostasis.
The erbium lasers are without equal in terms 
of hard tissue procedures and this unique 
position reflects the absorption of these lasers in
water and in the apatite minerals found in bone and
teeth. Research conducted in the mid 1980’s
demonstrated that the Er:YAG laser produced 
ablation of bone and methacrylate with minimal
thermal damage to adjacent tissue, opening the 
way for these lasers to be adopted widely in
orthopaedics, ENT and other forms of ablative
surgery (Figure 1).1 At the time, it was determined
that the thermal damage caused by Er:YAG 
laser ablation of skin, cornea, aorta and bone, when
200 microsecond pulses were used, was only 
10-50 microns of collagen damage at the 
smooth wall of the incisions, with zones of even
less (5-10 microns) when short pulse durations
were employed.2
Bone surgery
Bone is readily ablated by Er:YAG and Er,Cr:YSGG
laser radiation, and in clinical practice, this is typi-
cally undertaken using an accompanying water mist
spray, for five reasons: to maximize the transmission
of pulses responsible for the laser analgesic effect; to
prevent desiccation of bone; to maximize cooling of
Erbium dental lasers 
and bone modification
By Professor Laurence J. Walsh
“Erbium lasers
offer an attractive
alternative drilling
modality because
they do not
require physical
contact with the
bone in order to
drill holes; cut
bone with minimal
thermal damage;
and allow precise
control of bone
cutting...”
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Figure 1. A first generation Er:YAG laser from
the 1980’s, the KEY-Laser 1 from KaVo.
September/October 2008 Australasian Dental Practice 107
high tech | DENTISTRY
the site; to irrigate the site free of bone
debris; and to prevent plasma formation
(which would decrease ablation efficiency).
At low fluence, desiccation can prevent
efficient ablation of bone. The mechanism
of erbium laser ablation of bone is a com-
plex explosive removal process based on
thermo-mechanical shock waves. In studies
on desiccated bone, the total recoil
momentum caused by laser ablation has
been shown to be linearly related to the
radiant energy of the laser pulse. By evalu-
ating recoil momentum and mass loss data,
the average initial velocity of the material
ejected from the bone by the laser pulse is
some 230 to 280 metres per second.3
When used for an osteotomy, these
lasers give deep cuts with sharp edges,
and no charring or burning of adjacent
bone. The extent of adjacent tissue
thermal injury in bone, as determined by
histological studies, is on average only 5
microns.4 This makes the erbium lasers
preferred over rotary instruments for bone
cutting and opens the way for their wider
use in procedures where bone modifica-
tion is undertaken, a fact identified in the
literature as early as 1992.5,6 Similar bene-
fits have been noted for root resection
procedures undertaken with these lasers.7
Particular advantages of using erbium
lasers for bone surgery include:
• Simultaneous sterilization of the site;
• Less trauma than mechanical instru-
ments such as bone saws;8
• Osteoinduction in cortical bone by
altering the surface geometry in such 
a way as to promote ingrowth of 
new bone;9,10
• Absence of discomfort and vibration,
and reduced risk of trauma to adjacent
tissue;11
• Low risk for accidentally injuring adja-
cent soft tissues; and
• Microsurgical capabilities.
Bone cutting and 
bone modification
A clinical point of interest is the lack of
pressure needed when using an erbium
laser to cut bone. Bone stabilization during
hole drilling is often challenging due to the
need to apply pressure when using a con-
ventional mechanical drill. Erbium lasers
offer an attractive alternative drilling
modality because they do not require
physical contact with the bone in order to
drill holes; cut bone with minimal thermal
damage; and allow precise control of bone
cutting. Animal models of bone healing
have shown that there is no difference in
the amount of newly formed woven bone
at an osteotomy site or screw hole made by
either the erbium laser or a drill, with sim-
ilar thermal damage at the osteotomy sites
for laser and mechanically cut bone.14
There have been studies of implant place-
ment using an erbium laser versus a
conventional bur to prepare the sites, and
these show successful osseointegration
into a laser-prepared bone defect, with
comparable bone healing around titanium
implants with both methods.15 The finer
aspects of clinical technique for milling
holes for implant placement remain, how-
ever, to be perfected.
A particular application of erbium lasers
on bone is their use to perforate block grafts
of bone, to enhance incorporation into host
bone. Cortical bone grafts typically incorpo-
rate slowly, and are subject to complications
such as non-union, fatigue fracture and infec-
tion. In an attempt to improve osteoinduction
in cortical bone allografts, erbium laser perfo-
ration has been undertaken. Laser perforation
increases the available surface area and
thereby enhances incorporation of allografts
into the host bone.16 Unlike cuts with a bur,
the laser ablated areas have well-defined
edges and lack a smear layer, but are micro-
scopically rough with a high surface area.17
Laser energy can be delivered through
articulated arms or special non-glass
optical fibers (such as zirconium fluoride
and gallium oxide) to rigid sapphire or
quartz tips as well as to semi-flexible
doped quartz glass optical fibers. The pos-
sibility also exists to provide an autopilot
effect for using such tips to ablate bone,
for example, to drill through cortical bone,
but stop when reaching cancellous bone,18
by using optical or acoustic feedback. This
lends further weight to the concept of
Table 1. Current application for erbium lasers
Soft tissue
 Minor soft tissue surgery
 Resurfacing of oral mucosa
 Removal of gingival melanin pigmentation and gingival discolourations
 Ablative procedures such as gingivoplasty and peri-implant surgery
Bone
 Cutting bone effectively without burning, melting, or altering the 
calcium:phosphorus ratio of the irradiated bone12,13
 Hard tissue crown lengthening - “tunnelling” closed procedure
 Hard tissue crown lengthening - open flap procedure
 Milling sites for implant placement15
 Perforating block bone grafts to enhance osseo-induction16
 Ablation of bony tori
 Preparing bone for block grants, e.g. from the ramus
 Selective milling of bone, with the ability to incorporate autopilot systems18
Enamel and dentine
 Caries removal
 Surface conditioning (etching)
 Removal of resin, composite and GIC restorations
Other hard tissue sites
 Ablation of calculus during closed debridement
 Removal of granulation tissue during periodontal or periapical surgery
 Debridement and decontamination of implant surfaces
 Disinfection of periodontal pockets and root canals
 Removal of smear layer from root canals
 Root resection
108 Australasian Dental Practice September/October 2008
high tech | DENTISTRY
using these lasers as an alternative to sur-
gical handpieces for the removal of bone
in periodontal and in oral and maxillofa-
cial surgical procedures.19 The use of lasers
which operate with very short pulse dura-
tions, and handpieces which can achieve
small spot sizes can deliver highly efficient
bone ablation with minimal collateral
thermal damage, as well as histologically
earlier repair compared to steel surgical
burs.20 Use of ultrashort pulses and higher
pulse energies allows such lasers to be
used with greatest time efficiency, for pro-
cedures such as removal of bony tori, and
vertical ramus osteotomies.21 (Figure 2).
Current generation erbium lasers with
variable pulse duration include the Biolase
Waterlase MD (Figure 3) and Fotona
Fidelis 3 (Figures 4 and 5).
References
1. Nelson JS, Yow L, Liaw LH, Macleay L, Zavar RB, Oren-
stein A, Wright WH, Andrews JJ, Berns MW. Ablation of bone
and methacrylate by a prototype mid-infrared erbium:YAG
laser. Lasers Surg Med. 1988; 8:494-500.
2. Walsh JT, Flotte TJ, Deutsch TF. Er:YAG laser ablation of
tissue: effect of pulse duration and tissue type on thermal
damage. Lasers Surg Med. 1989; 9:314-26. 
3. Hibst R. Mechanical effects of erbium:YAG laser bone abla-
tion. Lasers Surg Med. 1992; 12:125-30.
4. Gonzalez C, van de Merwe WP, Smith M, Reinisch L. Comparison
of the erbium-yttrium aluminum garnet and carbon dioxide lasers for
in vitro bone and cartilage ablation. Laryngoscope. 1990; 100:14-7. 
5. Walsh LJ. The use of lasers in implantology: an overview. J
Oral Implantol. 1992; 18:335-40. 
6. Eversole LR, Rizoiu IM. Preliminary investigations on the
utility of an erbium, chromium YSGG laser. J Calif Dent Assoc.
1995; 23:41-7.
7. Paghdiwala AF. Root resection of endodontically treated teeth
by erbium: YAG laser radiation. J Endod. 1993; 19(2):91-4.
8. Buchelt M, Kutschera HP, Katterschafka T, Kiss H, Lang S,
Beer R, Losert U. Erb:YAG and Hol:YAG laser osteotomy: the
effect of laser ablation on bone healing. 7. Lasers Surg Med.
1994; 15:373-81. 
9. O’Donnell RJ, Deutsch TF, Flotte RJ, Lorente CA, Tomford
WW, Mankin HJ, Schomacker KT. Effect of Er:YAG laser
holes on osteoinduction in demineralized rat calvarial allo-
grafts. J Orthop Res. 1996; 14:108-13.
10. Lewandrowski KU, Tomford WW, Schomacker KT,
Deutsch TF, Mankin HJ. J Improved osteoinduction of cortical
bone allografts: a study of the effects of laser perforation and
partial demineralization. J Orthop Res. 1997; 15:748-56.
11. Komori T, Yokoyama K, Takato T, Matsumoto K. Clinical
application of the erbium:YAG laser for apicoectomy. J Endod.
1997; 23:748-50.
12. Kimura Y, Yu DG, Fujita A, Yamashita A, Murakami Y, Mat-
sumoto K. Effects of erbium,chromium:YSGG laser irradiation
on canine mandibular bone. J Periodontol. 2001; 72:1178-82.
13. Wang X, Ishizaki NT, Suzuki N, Kimura Y, Matsumoto K.
Morphological changes of bovine mandibular bone irradiated
by Er,Cr:YSGG laser: an in vitro study. J Clin Laser Med Surg.
2002; 20:245-50.
14. Lewandrowski KU, Lorente C, Schomacker KT, Flotte TJ,
Wilkes JW, Deutsch TF. Use of the Er:YAG laser for improved
plating in maxillofacial surgery: comparison of bone healing in
laser and drill osteotomies. Lasers Surg Med. 1996; 19:40-5.
15. el-Montaser M, Devlin H, Dickinson MR, Sloan P, Lloyd
RE. Osseointegration of titanium metal implants in erbium-
YAG laser-prepared bone. Implant Dent. 1999; 8:79-85.
16. Lewandrowski KU, Schollmeier G, Ekkemkamp A,
Uhthoff HK, Tomford WW.
Incorporation of perforated and demineralized cortical bone
allografts. Part I: radiographic and histologic evaluation.
Biomed Mater Eng. 2001; 11:197-207.
17. Sasaki KM, Aoki A, Ichinose S, Yoshino T, Yamada S,
Ishikawa I. Scanning electron microscopy and Fourier trans-
formed infrared spectroscopy analysis of bone removal using
Er:YAG and CO2 lasers. J Periodontol. 2002; 73:643-52.
18. Rupprecht S, Tangermann K, Kessler P, Neukam FW, Wilt-
fang J. Er:YAG laser osteotomy directed by sensor controlled
systems. J Craniomaxillofac Surg. 2003; 31:337-42.
19. van As G. Erbium lasers in dentistry. Dent Clin North Am.
2004; 48:1017-59.
20. de Mello ED, Pagnoncelli RM, Munin E, Filho MS, de
Mello GP, Arisawa EA, de Oliveira MG. Comparative histolog-
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About the author
Professor Laurence J. Walsh is the tech-
nology editor of Australasian Dental
Practice magazine. He is also a noted
commentator on and user of new technolo-
gies and is the Head of The University of
Queensland School of Dentistry.
Figure 3. Waterlase MD system from
Biolase with variable pulse duration.
Figure 4. Fotona Fidelis Plus high
power laser system with variable pulse
duration and specific handpieces for
bone surgery.
Figure 5. Fidelis handpieces for conven-
tional soft and hard tissue surgery (A & B)
and for oral surgery (C & D). The latter
have smaller spot sizes and positioning
aids incorporated into their design.
Figure 2. Before (top) and after (bottom)
clinical images of a case where bilateral
tori have been removed prior to full
lower denture construction, using an
erbium laser. Mucosal anaesthesia was
obtained immediately before suturing,
however initial incision of the mucosa
and the removal of bone was conducted
without anesthesia.


Erbium dental lasers and bone modification

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Erbium dental lasers and bone modification

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