The International Journal of Periodontics & Restorative Dentistry© 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.
NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.

67

Innovative Regeneration Technology to
Solve Peri-implantitis by Er:YAG Laser
Based on the Microbiologic Diagnosis:
A Case Series
Toshiaki Yoshino, DDS, PhD1
Atsuhiko Yamamoto, DDS, PhD2
Yoshihiro Ono, DDS3

Peri-implantitis is an emerging problem, and corrective therapy requires a methodfor decontaminating the complex surface structure of the implant body andsterilizing the surrounding tissue. The erbium:yttrium-aluminum-garnet (Er:YAG) laser
has proven to effectively allow tissue to regenerate when used for peri-implantitis.
The power of the Er:YAG laser is absorbed by a water molecule; therefore, its
target neither rises in temperature nor carbonizes. An antibacterial remedy basedon the bacteriologic diagnosis, followed by debridement and sterilization of theimplant surface and peri-implant tissues by Er:YAG laser is efficacious for periimplantitis treatment. The aim of this report was to present the effectiveness of the
Er:YAG laser for peri-implant bone regeneration. This case series of two patients
showed that antibiotic therapy reduced the bacterial amount from the periimplantitis sites significantly and that Er:YAG laser therapy, along with the boneaugmentation, enhanced bone regeneration in the peri-implant bony defects.
(Int J Periodontics Restorative Dent 2015;35:67–73. doi: 10.11607/prd.2116)

Private Practice, Yokohama, Japan; Lecturer, The Japan Institute for Advanced Dental Studies,Tokyo, Japan.
2Lecturer, The Japan Institute for Advanced Dental Studies, Tokyo, Japan; Private Practice,
Osaka, Japan.
3Director, The Japan Institute for Advanced Dental Studies, Tokyo, Japan.
1Correspondence to: Dr Toshiaki Yoshino, Yoshino Dental Office, Yokohamanishikyodo Bldg 5F,
Kitasaiwai 1-2-13, Nishiku, Yokohama, Kanagawa, Japan; fax: 81-45-317-3007;
email: yoshino@yoshino-do.jp.
©2015 by Quintessence Publishing Co Inc.

Implant therapy has become a routine dental treatment modality and,frequently, the first choice to replace
missing teeth. The texture of implantsurfaces has been improved to expedite osseointegration, but there issome concern that a rough surface
to the collar of the implant may introduce the risk of bacterial infection
described as peri-implantitis. Periimplantitis and periodontitis are inflammatory diseases with a bacterial
etiology,1 but they differ in the factthat the implant has a complex artificial surface placed in alveolar bone.
The treatment of any problem requires an appropriate diagnosis and,if possible, an understanding of the
etiology before initiating treatment.
The debridement of a complex implant surface that has become infected is a significant challenge.
The possibility of regenerating lostbone and reestablishing bone-implant contact without a clean surface is unlikely. In this study, theerbium:yttrium-aluminum-garnet(Er:YAG) laser was used to decontaminate the implant surface. This hardtissue laser has the capability of being absorbed by water molecules,2,3
which prevents a rise in temperature

Volume 35, Number 1, 2015
© 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.
NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.

68

Fig 1 Severe bone resorption could beobserved at the mandibular right second
premolar and first molar sites.

Fig 2 Before regenerative surgery, a lackof keratinized tissue and a shallow vestibule
were observed.

Fig 3 After flap reflection, severe saucerlike bone resorption and black subgingival
calculus were visible on the implants.
The implants were irradiated to remove
subgingival calculus and to detoxify andsterilize the implant surface without heat or
carbonization using an Er:YAG laser.

that might carbonize or cause thermal degeneration to the surrounding tissues.4 This device causes theleast damage with little or no thermal
alteration or melting of the titanium
surface at a specific energy band.3,5Bacteria on the irradiated surface are
eradicated without heat. The device
is also reported to be capable ofdetoxifying lipopolysaccharide (LPS)
and improving the healing activityof vital tissues.6 When treating periimplantitis, it is effective for debridement of the complex body surface,decortification of bone, sterilizationof the soft and hard peri-implant tissues, and detoxification of bacterial
metabolites.7
This study demonstrated favorable bone regeneration for patients
suffering from peri-implantitis byperforming antibacterial therapy
based on bacteriologic and immunologic testing followed by debridement and sterilization of the implantsurface and peri-implant tissues using Er:YAG laser. This laser also iseffective for periodontal resective

therapy, scaling, and the removal ofbone and cementum.8

metronidazole was administeredfor 4 weeks for the first case,9 andazithromycin, whose effect lasts a
week after 3 continuous days of administration, was taken for 3 days
as the antibacterial therapy for thesecond case.10 Laser irradiation was
followed by sterilization. The authors
used Er:YAG laser (Erwin AdvErL,
J. Morita) with different types of tips,
including the straight-irradiation tip(CF400) for bone penetration, theside-irradiation tip (P400T) for debridement of the implant body, andthe straight-and-side irradiation tip(PS600T) to remove the inner marginal epithelium of the gingival sulcus. The output levels were selectedfrom the preset panel and were
150 mJ at 10 pulses per second(pps), 40 mJ at 10 pps, and 70 mJ at
25 pps, respectively. Equal amountsof freeze-dried bone allograft (Oragraft Cortical, LifeNet) and autogenous bone were mixed and soakedwith recombinant human plateletderived growth factor BB (Gem 21S,
Osteohealth) and were utilized as

Method and materials
Two patients with prominent loss ofalveolar bone due to peri-implantitis
were treated by disinfection with the
Er:YAG laser and a bone graft regeneration procedure after diagnosis byradiographic examination. A bacteriologic examination with the polymerase chain reaction (PCR)-invader
method was performed to measure
the total count of bacteria, the number of each bacterial flora, and thepartial ratio of each flora. The following bacterial species were examined: Porphyromonas gingivalis,
Tannerella forsythia, Treponema
denticola, Aggregatibacter actinomycetemcomitans, and Prevotellaintermedia. These factors were measured immediately after the periimplantitis diagnosis, after antibacterial therapy, and after surgicaltherapy. Amoxicillin combined withThe International Journal of Periodontics & Restorative Dentistry© 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.
NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.

69

Fig 4 (left) Preoperative bone resorption around the mandibular
right second premolar was 5.91 mm deep and 4.25 mm mesially.
(right) The depth of buccal bone resorption on the mandibular rightsecond premolar was 7.28 mm. Measurement of bone resorption
around the implants was performed by dental cone beam CT.

Fig 5 Measurement of a significant gain in radiopaque tissue surrounding the implants after 10 months. Remarkably increased hardtissue is observed (+7.21 mm vertically and +4.22 mm horizontally).
Bone growth over the first thread was observed (1.62 mm mesially, 1.84 mm vertically, and 2.20 mm buccally on mandibular rightsecond premolar.

Fig 6 Clinical findings at reentry at 10
months. Significant bonelike tissue wasregenerated.

Fig 7 Additional vestibuloplasty and a free gingival graft were performed, as evident inthe (left) before and (right) after images (clinical and radiographs).

the bone graft material. A polylactate membrane (GC) was fixed by
the cover screw. To evaluate the hardtissue, dental cone beam computed
tomography (CBCT; Veraviewepocs
3D, J. Morita) was used. Horizontal and vertical bone defects in themesiodistal sections were evaluatedbefore regenerative therapy and 9months and 1.5 years after.

Results
Case 1 (Figs 1 to 7)

A 62-year-old woman received implants in the mandibular right posterior area, then presented after 6 years
complaining of an unpleasant sensation at that site. The radiographic diagnosis was peri-implantitis.

The implant (Steri-Oss, Nobel Biocare) had a titanium plasma-sprayedsurface. The results of the bacterial testing are listed in Table 1.
There was an excessive ratio of
periodontopathic bacterial flora detected; therefore, amoxicillin andmetronidazole were administeredorally. A panoramic radiograph and
CBCT after antibacterial therapy,

Volume 35, Number 1, 2015
© 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.
NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.

70

Table 1 Case 1 bacterial analysis of mandibular right firstmolar site before and after oral antibiotics treatment
Count

Ratio to total (%)

Bacteria

BeforeAfter
BeforeAftertreatment treatment treatment treatment Normal

Total

100,000

3,700

–

–

–

0

0

0.00

0.00

< 0.0149,000

0

49.00

0.00

< 0.5

A actinomycetemcomitans
P gingivalis
T forsythia

2,800

0

2.80

0.00

< 0.5

T denticola

15,000

110

15.00

2.97

< 5.0

P intermedia

390

0

0.39

0.00

< 2.5

Fig 8 Preoperative radiograph. Bone resorption is evident on the mesial and distal
surfaces of the distal implant.

Fig 9 There is a paucity of keratinizedgingiva for the distal implant.

Case 2 (Figs 8 to 12)

A 68-year-old woman received three
implants in the posterior region ofher right maxilla. A panoramic radiograph 3 years later revealed boneabsorption and demonstrated periimplantitis. The result of the bacterial testing is presented in Table 2.
A hydroxyapatite-coated implant(Steri-Oss) replaced the first molar
because of poor initial fixation. Interestingly, periodontopathic bacterial
flora was detected in this site, but
not on the machined surface of thehybrid-design implant (Osseotite,
Biomet 3i) in the adjacent second
premolar site. Regenerative therapy,
along with Er:YAG laser irradiation,
was performed as described previously following antibacterial therapy. Bony tissue augmentation was
identified as 3.19 mm vertically and0.93 mm horizontally (see Fig 11).
The patient was in good condition
2 years after treatment, with noevidence of periodontal bacteria
detected during the maintenancephase. The prognosis was considered to be favorable.

Discussion

Fig 10 Preoperative measurement by cone beam CT. (left) Bone
resorption (4.1 mm vertically and 1.7 mm horizontally) is evident.
(right) The depth of buccal bone resorption was 4.03 mm.

Er:YAG laser irradiation, and bone
grafting revealed bone regeneration to be 4.22 mm horizontallyand 7.21 mm vertically 9 months
after the regenerative therapy (seeFigs 4 and 5). The patient has been
maintaining good condition for 2
years after treatment, and no periodontopathic bacteria have been
detected.

The history of the diagnostic criteria of implant complications reflects
the history of success criteria for
implant therapy. The 1978 National
Institutes of Health Development
Conference at Harvard recognized
several criteria that are not applicable for osseointegration, eg, mobility of less than 1 mm and verticalbone resorption up to one-thirdof the implant length.11 In 1986,

The International Journal of Periodontics & Restorative Dentistry© 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.
NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.

71

Fig 11 (left) Measurements of vertical and horizontal ridge
augmentation by cone beam CT revealed gains of 3.19 mm vertically and 0.93 mm horizontally 2 years after regenerative surgery
around the implant site. (right) Severe buccal bone resorption wasobserved.

Fig 12 After the bone grafting was successful, a vestibuloplasty and free gingival
graft were performed without any relapseof peri-implantitis.

Table 2 Case 2 bacterial analysis of maxillary right second premolar (hybrid-design implant)
and first molar (HA implant) sites before and after oral antibiotics treatment
Count
Tooth 16* (HA)

Ratio to total (%)

Tooth 15* (hybrid)

Tooth 16* (HA)

Tooth 15* (hybrid)

Bacteria

BeforeAfter
BeforeAfter
BeforeAfter
BeforeAftertreatment treatment treatment treatment treatment treatment treatment treatment Normal

Total

17,798,480

2,456,400

98,36010,680

–

–

–

–

–

0

0

0

0

0.00

0.00

0.00

0.00

< 0.01

P gingivalis

199,680

0

0

0

1.12

0.00

0.00

0.00

< 0.5

T forsythia

75,640

0

0

0

0.42

0.00

0.00

0.00

< 0.5

T denticola

80,320

0

0

0

0.45

0.00

0.00

0.00

< 5.0

P intermedia

663,600

0

0

0

3.73

0.00

0.00

0.00

< 2.5

A actinomycetemcomitans

HA = hydroxyapatite.
*FDI tooth-numbering system.

Albrektsson introduced the criteriaof success that are still applicable
today.12 At present, the success criteria resolved at the Toronto Conference on Osseointegration in1998 are adopted as the standard.
Namely, vertical bone resorptionof less than 0.2 mm per year after the implant is in function is acceptable. Infection and bone loss
at the osseointegrated interface

fails to accomplish this criterion.
The fact that the bacterial species
detected around implant sites are
similar to those found around natural teeth13–15 and that periodontal
pathogenic bacterial species areoften detected on a failed implantsurface suggests that peri-implant
infection is similar to periodontitis.16–18 It is very important to reduceor eliminate periodontal pathogens

when treating periodontal disease
if a bacterial test reveals an excessive bacterial count. It is rational tosuggest that no implant should beplaced before completing definitive
periodontal treatment.19 Like periodontal treatment, the treatmentof peri-implantitis requires eliminating probing depths, bleeding on
probing, and exudate. In the past,probing depth at implants was not

Volume 35, Number 1, 2015
© 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.
NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.

72
considered an important parameter; however, at present it is considered to be a necessary measure
to detect infection or attachment
loss. Lang et al accumulated thesefindings and summarized them inCumulative Interceptive Supportive
Therapy,20 which is considered tobe the current guideline for periimplantitis treatment. The countof each type of bacterial flora andits ratio to total bacterial count, as
well as other physical conditionsof the patient, must be considered
before antibacterial therapy is initiated. Oral antibacterial medication
should be based on the recommendations of the American Academy of Periodontology,9 and the
difficulty of decontaminating therough microstructure of contemporary implants must be recognized. It
is no easy task to expose and clean
the surface of a deep infrabony defect on a natural tooth, even withthe possibility of the exposed dentinal tubules absorbing topical antibiotics. Once infection has resulted
in peri-implant tissue destruction, it
never heals spontaneously, and advanced peri-implantitis can lead tothe need to remove the implant. At
this point in time, the authors consider the Er:YAG laser to be the ideal tool for addressing this situation.
The Er:YAG laser has a high energy absorption rate by water molecules with minimum temperature
increase, which leads to effectivesterilization of the irradiated surface with less carbonization21 andless damage to the titanium surface.5 Because of these merits, theauthors suggest the Er:YAG laser

as the first choice for debridementof the implant surface. The conventional air ablation method may
perform effective debridement;
however, it scatters microscopic
granules that may penetrate andreside in the soft tissue. In addition to avoiding the latter issue, the
Er:YAG laser detoxifies LPS5,6,22 andcan accelerate the wound healingmechanism8,23 compared with theconventional method. Phototherapy, including laser therapy, does
not require direct contact with thetarget, so it can irradiate in various
directions, which is very effective inlight of the complicated structure of
the implant threads.

Conclusions
The recommended composite approach to peri-implantitis should
be initiated with bacterial identification leading to antibiotic treatment. When bone-implant contact
has been compromised, resulting inbone loss, the complex rough surfaces of implants are difficult to decontaminate. Irradiation by Er:YAG
laser is proposed as the appropriate
approach to cleansing the implantsurface and preparing it for regenerative procedures.

Acknowledgments
The authors are deeply grateful to the J. Morita
Corporation for its helpful advice on using thelaser device. The authors reported no conflicts of interest related to this study.

References
1. Albrektsson T, Isidor F (eds). Consensus
report of session IV. In: Lang NP, Karring
T (eds). Proceedings of the 1st European
Workshop on Periodontology. London:
Quintessence, 1994:365–369.
2. Hale GM, Querry MR. Optical constantsof water in the 200-nm to 200-microm
wavelength region. Appl Opt 1973;12:555–563.
3. Yamamoto A, Tanabe T. Treatment ofperi-implantitis around TiUnite-surface
implants using Er:YAG laser microexplosions. Int J Periodontics Restorative Dent
2013;33:21–29.
4. Aoki A, Sasaki KM, Watanabe H, Ishikawa
I. Lasers in nonsurgical periodontal therapy. Periodontol 2000 2004;36:59–97.
5. Matsuyama T, Aoki A, Oda S, Yoneyama
T, Ishikawa I. Effects of the Er:YAG laser
irradiation on titanium implant materials and contaminated implant abutment
surfaces. J Clin Laser Med Surg 2003;21:
7–17.
6. Folwaczny M, Aggstaller H, Mehl A, Hickel R. Removal of bacterial endotoxin fromroot surface with Er:YAG laser. Am J Dent
2003;16:3–5.
7. Aleksic V, Aoki A, Iwasaki K, et al. Lowlevel Er:YAG laser irradiation enhances osteoblast proliferation throughactivation of MAPK/ERK. Lasers Med Sci
2010;25:559–569.
8. Folwaczny M, Benner KU, Flasskamp
B, Mehl A, Hickel R. Effects of 2.94 microm Er:YAG laser radiation on root surfaces treated in situ: A histological study.
J Periodontol 2003;74:360–365.
9. Califano JV; Research, Science and Therapy Committee, American Academy of
Periodontology. Position paper: Periodontal diseases of children and adolescents. J Periodontol 2003;74:1696–1704.
10. Gomi K, Yashima A, Nagano T, Kanazashi
M, Maeda N, Arai T. Effects of full-mouthscaling and root planing in conjunction
with systemically administered azithromycin. J Periodontol 2007;78:422–429.
11. Grunder U, Gracis S, Capelli M. Influenceof the 3-D bone-to-implant relationshipon esthetics. Int J Periodontics Restorative Dent 2005;25:113–119.
12. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: A review andproposed criteria of success. Int J Oral
Maxillofac Implants 1986;1:11–25.

The International Journal of Periodontics & Restorative Dentistry© 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.
NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.

73

13. Friberg B, Jemt T, Lekholm U. Early failures in 4,641 consecutively placed Brånemark dental implants: A study from stage
1 surgery to the connection of completed
prostheses. Int J Oral Maxillofac Implants
1991;6:142–146.
14. Quirynen M, Listgarten MA. Distributionof bacterial morphotypes around natural teeth and titanium implants ad modum Brånemark. Clin Oral Implants Res
1990;1:8–12.
15. Mombelli A, Marxer M, Gaberthüel T,
Grunder U, Lang NP. The microbiota ofosseointegrated implants in patients witha history of periodontal disease. J Clin
Periodontol 1995;22:124–30.
16. Pontoriero R, Tonelli MP, Carnevale G,
Mombelli A, Nyman SR, Lang NP. Experimentally induced peri-implant mucositis.
A clinical study in humans. Clin Oral Implants Res 1994;5:254–259.

17. Mombelli A, Lang NP. Antimicrobial
treatment of peri-implant infections. Clin
Oral Implants Res 1992;3:162–168.
18. Rosenberg ES, Torosian JP, Slots J. Microbial differences in 2 clinically distinct
types of failures of osseointegrated implants. Clin Oral Implants Res 1991;2:
135–144.
19. Quirynen M, Abarca M, Van Assche N,
Nevins M, van Steenberghe D. Impact
of supportive periodontal therapy andimplant surface roughness on implant
outcome in patients with a history of
periodontitis. J Clin Periodontol 2007;34:
805–815.
20. Lang NP, Berglundh T, Heitz-Mayfield LJ,
Pjetursson BE, Salvi GE, Sanz M. Consensus statements and recommend clinicalprocedures regarding implants survival
and complications. Int Oral Maxillofac
Implants 2004;19(suppl):150–154.

21. Yoshino T, Aoki A, Oda S, et al. Longterm histologic analysis of bone tissue
alteration and healing following Er:YAG
laser irradiation compared to electrosurgery. J Periodontol 2009;80:82–92.
22. Yamaguchi H, Kobayashi K, Osada R, etal. Effects of irradiation of an erbium:YAG
laser on root surfaces. J Periodontol
1997;68:1151–1155.
23. Schwarz F, Jepsen S, Herten M, Aoki A,
Sculean A, Becker J. Immunohistochemical characterization of periodontal woundhealing following nonsurgical treatment
with fluorescence controlled Er:YAG laser
radiation in dogs. Lasers Surg Med 2007;
39:428–440.

Volume 35, Number 1, 2015
© 2015 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.
NO PART MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.