laser in dentistry

Scientific Report: Er,Cr:YSGG Laser Effects on Dentin and Collagen

Case Reports: Treatment of Moderate Chronic Periodontitis;Gingivoplasty, Frenectomy, and Second-Stage Implant Recovery; Establishing a Gingival Smile Line; Treatment of Lip Hemangiomas

The Official Journal of the Academy of Laser Dentistry 2008 Vol. 16 No. 1The Official Journal of the Academy of Laser Dentistry 2008 Vol. 16 No. 1

Caries Detection by Quantitative Light-Induced FluorescenceSee the technology review article on page 6

Academy of Laser Dentistry3300 University Drive, Suite 704

Coral Springs, FL 33065

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TA B L E O F CO N T E N T SThe official journal of the

Academy of Laser Dentistry

Editor in ChiefJohn D.B. Featherstone, MSc, PhDSan Francisco, CA [email protected]

Managing EditorGail S. Siminovsky, CAE, Executive DirectorCoral Springs, FL [email protected]

Consulting EditorJohn G. Sulewski, MA Huntington Woods, MI [email protected]

Associate Editors Donald J. Coluzzi, DDSPortola Valley, CA [email protected] P.A. Parker, BDS, LDS RCS, MFGDP Harrogate, Great Britain

[email protected]

Editorial BoardJohn D.B. Featherstone, MSc, PhDGail S. Siminovsky, CAEJohn G. Sulewski, MADonald J. Coluzzi, DDSSteven P.A. Parker, BDS, LDS RCS, MFGDPAlan J. Goldstein, DMDDonald E. Patthoff, DDSPeter Rechmann, Prof. Dr. med. dent.

PublisherMax G. MosesMember Media

1844 N. LarrabeeChicago, IL 60614

312-296-7864Fax: 312-896-9119

[email protected]

Design and LayoutDiva Design

2616 Missum PointSan Marcos, TX 78666

512-665-0544Fax: 512-392-2967

[email protected]

Editorial Office3300 University Drive, Suite 704

Coral Springs, FL 33065

954-346-3776 Fax 954-757-2598

[email protected]

The Academy of Laser Dentistry is a not-for-profitorganization qualifying under Section 501(c)(3) ofthe Internal Revenue Code. The Academy of LaserDentistry is an international professional member-ship association of dental practitioners and sup-porting organizations dedicated to improving thehealth and well-being of patients through theproper use of laser technology. The Academy isdedicated to the advancement of knowledge,research and education and to the exchange ofinformation relative to the art and science of theuse of lasers in dentistry. The Academy endorsesthe Curriculum Guidelines and Standards forDental Laser Education.

Member American Association of Dental EditorsThe Journal of Laser DentistryThe mission of the Journal of Laser Dentistry is to provide a professional quarterly journalthat helps to fulfill the goal of information dissemination by the Academy of Laser Dentistry.The purpose of the Journal of Laser Dentistry is to present information about the use of lasersin dentistry. All articles are peer-reviewed. Issues include manuscripts on current indicationsfor uses of lasers for dental applications, clinical case studies, reviews of topics relevant tolaser dentistry, research articles, clinical studies, research abstracts detailing the scientificbasis for the safety and efficacy of the devices, and articles about future and experimental procedures. In addition, featured columnists offer clinical insights, and editorials describe personal viewpoints.

E D I TO R S V I E WUnderstanding Our Laser Tools to Better Serve Our Patients ..................5John D.B. Featherstone, MSc, PhD

COV E R F E AT U R EC L I N I C A L R E V I E WSupplementary Methods for Detection and Quantification of Dental Caries........................................................................................................6Lena Karlsson, RDH; Sofia Tranus, DDS, PhD

SC I E N T I F I C R E P O RT Effect of Er,Cr:YSGG Laser on Human Dentin Collagen: A Preliminary Study ............................................................15Eleftherios-Terry Farmakis, DDS, MDSc, PhD; Konstantinos Kozyrakis,DDS, PhD; Evangelos G. Kontakiotis, DDS, PhD; Kouvelas NikolaosDDS, PhD

A DVA N C E D P R O F I C I E N C Y C A S E ST U D I E SIntroduction ............................................................................................................22

Nd:YAG Laser-Assisted Treatment of Moderate Chronic Periodontitis........................................................................23Mary Lynn Smith, RDH; McPherson, Kansas

Use of an 810-nm Diode Laser in a Combined Gingivoplasty,Frenectomy, and Second-Stage Implant Recovery Procedure ................30Steven Parker, BDS, LDS RCS, MFGDP; Harrogate, North Yorks, Great Britain

Establishing a Maintainable Esthetic Gingival Smile Line with an Er:YAG Laser ......................................................................37Charles R. Hoopingarner, DDS, Houston, Texas

Use of an 810-nm Diode Laser in the Treatment of Multiple Hemangiomata of the Lip ............................................................43Steven Parker, BDS, LDS RCS, MFGDP; Harrogate, North Yorks, Great Britain

R E S E A R C H A B ST R AC T SLaser Treatment of Vascular Lesions of the Lip ..........................................48

Journal of Laser Dentistry

Journal of Laser Dentistry: Guidelines for AuthorsThe Academy of Laser Dentistry Welcomes Your Articles for Submission

The Journal of Laser Dentistry publish-es articles pertaining to the art, science,and practice of laser dentistry andother relevant light-based technologies.Articles may be scientific and clinical innature discussing new techniques,research, and programs, or may beapplications-oriented describing specificproblems and solutions. While lasersare our preferred orientation, otherhigh-technology articles, as well asinsights into marketing, practice man-agement, regulation, and other aspectsof dentistry that may be of interest tothe dental profession, may be appropri-ate. All articles are peer-reviewed priorto acceptance, modification, or rejection.

These guidelines are designed tohelp potential authors in writing andsubmitting manuscripts to the Journalof Laser Dentistry, the official publica-tion of the Academy of Laser Dentistry(ALD). Please follow these instructionscarefully to expedite review and process-ing of your submission. Manuscriptsthat do not adhere to these instructionswill not be accepted for consideration.The Academy of Laser Dentistry and theeditors and publisher of the Journal ofLaser Dentistry endorse the UniformRequirements of Manuscripts Submittedto Biomedical Journals (www.icmje.org).The Journal reserves the right to reviseor rescind these guidelines.

Authors are advised to read the morecomprehensive Guidelines for Authorsand required forms available by mail oronline at www.laserdentistry.org.

Manuscript EligibilitySubmitted manuscripts must be writtenclearly and concisely in AmericanEnglish and appropriate for a scholarlyjournal. Write in active voice and usedeclarative sentences. Manuscripts willbe considered for publication on the con-dition that they have been submittedexclusively to the Journal, and have notbeen published or submitted for publica-tion in any part or form in another publi-cation of any type, professional or lay, orin any language elsewhere, and with theunderstanding that they will not bereprinted without written consent fromboth the managing editor and the author.

PermissionsDirect quotations of 100 or more words,and illustrations, figures, tables, orother materials (or adaptations thereof)that have appeared in copyrightedmaterial or are in press must be accom-panied by written permission for theiruse in the Journal of Laser Dentistryfrom the copyright owner and originalauthor along with complete informationregarding source, including (as applica-

ble) author(s), title of article, title ofjournal or book, year, volume number,issue number, pages. Photographs ofidentifiable persons must be accompa-nied by valid signed releases indicatinginformed consent. When informed con-sent has been obtained from anypatient, identifiable or not, it should benoted in the manuscript. The appropri-ate Permission Letters must be submit-ted with the manuscript. Suggestedtemplate letters are available online.

CopyrightAll manuscript rights shall be trans-ferred to the Journal of Laser Dentistryupon submission. Upon submission ofthe manuscript, authors agree to sub-mit a completed Copyright TransferAgreement form, available online. If themanuscript is rejected for publication,all copyrights will be retained by theauthor(s).

CommercialismALD members are interested in learn-ing about new products and serviceofferings, however ALD stresses thatsubmitted manuscripts should be edu-cational in nature. The emphasis is onscientific research and sound clinicaland practical advice, rather than pro-motion of a specific product or service.

Disclosure of Commercial RelationshipsAccording to the Academys Conflict ofInterest and Disclosure policy, manu-script authors and their institutions areexpected to disclose any economic orfinancial support, as well as any per-sonal, commercial, technological, aca-demic, intellectual, professional, philo-sophical, political, or religious interestsor potential bias that may be perceivedas creating a conflict related to thematerial being published. Such condi-tions may include employment, consul-tancies, stock ownership or other equityinterests, honoraria, stipends, paidexpert testimony, patent ownership,patent licensing arrangements, royal-ties, or serving as an officer, director, orowner of a company whose products, orproducts of a competitor, are identified.Sources of support in the form of con-tracts, grants, equipment, drugs, mate-rial donations, clinical materials, specialdiscounts or gifts, or other forms of sup-port should be specified. The roles of thestudy or manuscript sponsor(s), if any,are to be described. Disclosure state-ments are printed at the end of the arti-cle following the authors biography.This policy is intended to alert the audi-ence to any potential bias or conflict sothat readers may form their own judg-ments about the material being pre-

sented. Disclosure forms are to besigned by each author. Manuscripts willnot be reviewed without the Journalhaving this form on file.

The Academy of Laser Dentistry alsorequires that authors disclose whetherany product discussed in their manu-script is unlabeled for the use discussedor is investigational.

The Disclosure Statement form isavailable online and must be submittedwith the manuscript.

Manuscript TypesSubmissions to the Journal should belimited to one of the types indicatedbelow. Scientific / Technology / Clinical

Review Case Reports and Clinical Case

Studies Scientific / Clinical Research Randomized Clinical Trials Advances in Dental Products Trends Practice Management Guest Editorials and Essays Letters to the Editor Book Reviews

Manuscript Preparation andSubmissionFormatAll submitted manuscripts should bedouble-spaced, using 12 pt. font sizewith at least 6 mm between lines.Submit manuscripts in Microsoft Word(.doc), using either the Windows orMacintosh platform. Manuscripts mustbe submitted electronically in this for-mat. Hard copy-only submissions willnot be accepted.

Unacceptable FormatsThe following submission formats areunacceptable and will be returned: Manuscripts submitted in desktop

publishing software PowerPoint presentations Any text files with embedded images Images in lower than the minimum

prescribed resolution.

Manuscript ComponentsTitle PageThe title page of the manuscript shouldinclude a concise and informative titleof the article; the first name, middle ini-tial(s), and last name of each author,along with the academic degree(s), pro-fessional title(s), and the name andlocation (city, state, zip code) of currentinstitutional affiliation(s) and depart-ment(s). Authors who are private practi-tioners should identify their location(city, state, and country). Include allinformation in the title that will make

electronic retrieval of the article sensi-tive and specific. Titles of case studiesshould include the laser wavelength(s)and type(s) utilized for treatment (forexample, 810-nm GaAlAs diode).

Identify the complete address, busi-ness and home telephone numbers, faxnumber, e-mail address, and Web siteaddress (if any) for all authors. Identifyone author as the corresponding author.Unless requested otherwise, the e-mailaddress is published in the Journal.

AbstractA self-standing summary of the text ofup to 250 words should precede theintroduction. It should provide an accu-rate summary of the most significantpoints and be representative of theentire articles content. Provide the con-text or background for the article, basicprocedures, main findings and conclu-sions. Emphasize new or importantaspects. Do not use abbreviations (otherthan standard units of measurement) orreferences in the abstract.

Author(s) BiographyProvide a brief, current biographicalsketch of each author that includes pro-fessional education and professionalaffiliations. For authors who hold teach-ing positions, include the title, depart-ment, and school. For authors who arein federal service, include rank or titleand station.

ReferencesReferences are to be cited in the text bynumber in order of appearance, withthe number appearing either as asuperscript or in brackets. The refer-ence list should appear at the end of themanuscript with references in order offirst appearance in the text of the man-uscript. The reference list must betyped double-spaced on a separate pageand numbered in the same sequence asthe reference citations appear in thetext. Prior to submission, all referencesare to be properly prepared in the cor-rect format, checked for completeness,carefully verified against their originaldocuments, and checked for accuratecorrespondence between referencescited in the text and listed in theReferences section. For journal citations, include sur-

names and all initials of all authors,complete title of article, name of jour-nal (abbreviated according to the U.S.National Library of Medicine(www.nlm.nih.gov/services/lpabbrev.html), year of publication,volume, issue number, and completeinclusive page numbers. If abstractsare cited, add the abstract numberafter the page number.

For book citations, specify surnamesand initials of all authors, chapternumber and title (if applicable), edi-

tors surnames and initials, booktitle, volume number (if applicable),edition number (if applicable), cityand full name of publisher, year ofpublication, and inclusive page num-bers of citation.

For government publications or bul-letins, identify the author(s) (if given);title; department, bureau, agency, oroffice; the publication series, report,or monograph number; location ofpublisher; publisher; year of publica-tion; and inclusive page numbers.

For articles published online but notyet in print, cite with the papersDigital Object Identifier (DOI) addedto the end of the reference.

For Web citations, list the authorsand titles if known, then the URLand date it was accessed.

For presentations, list the authors,title of presentation, indication thatthe reference is a lecture, name ofconference or presentation venue,date, and location.

Illustration Captions and LegendsAll illustrations must be accompanied byindividual explanatory captions whichshould be typed double-spaced on a sepa-rate page with Arabic numerals corre-sponding to their respective illustration.

TablesTables must be typewritten double-spaced, including column heads, data,and footnotes, and submitted on sepa-rate pages. The tables are to be cited inthe text and numbered consecutively inArabic numerals in the order of theirappearance in the text. Provide a con-cise title for each table that highlightsthe key result.

IllustrationsIllustrations include photographs, radi-ographs, micrographs, charts, graphs,and maps. Each should be numbered andcited in the text in the order of appear-ance and be accompanied by explanatorycaptions. Do not embed figures withinthe manuscript text. Each figure andtable should be no larger than 8-1/2 x 11inches. Digital files must measure at

least 5 inches (127 mm) in width. Theimage must be submitted in the size itwill be printed, or larger. Illustrationsare to augment, not repeat, material inthe text. Graphs must not repeat datapresented in tables. Clinical photographsmust comply with ALDs Guidelines forClinical Photography, available online.Authors are to certify in a cover letterthat digitized illustrations accuratelyrepresent the original data, condition, orimage and are not electronically edited.

Publisher and Copyright HolderThe Journal of Laser Dentistry is pub-lished by Max G. Moses, MemberMedia, 1844 N. Larrabee, Chicago, IL60614, Telephone: (312) 296-7864; Fax:(312) 896-9119. The Journal of LaserDentistry is copyrighted by TheAcademy of Laser Dentistry, 3300University Drive, Suite 704, CoralSprings, FL 33065, Telephone: (954)346-3776; Fax: (954) 757-2598.

Articles, Questions, IdeasQuestions about clinical cases, scientificresearch, or ideas for other articles maybe directed to John D.B. Featherstone,Editor-in-Chief, by e-mail: [email protected].

Submission of Filesby E-mail:Send your completed files by e-mail(files up to 10 MB are acceptable). Iffiles are larger than 10 MB, they maybe compressed or sent as more than onefile, with appropriate labels. Filesshould be submitted to:John D.B. Featherstone, Editor-in-Chiefby e-mail: [email protected].

By Federal Express or OtherInsured Courier:If using a courier, please send the file asa CD-ROM, include a hard copy of yourmanuscript and also send a verificationby e-mail to Gail Siminovsky ([email protected]).Gail SiminovskyAcademy of Laser Dentistry3300 University Drive, Suite 704Coral Springs, FL 33065Phone: (954) 346-3776.

Summary of Illustration Types and Specifications

IllustrationType

Definition and ExamplesPreferredFormat

RequiredResolution

Line Art andVector Graphics

Black and white graphic with noshading (e.g., graphs, charts, maps)

EPS or JPG 1200 DPI

Halftone Art

Photographs, drawings, or paint-ing with fine shading (e.g., radi-ographs, micrographs with scalebars, intraoral photographs)

TIFF orJPG

300 DPI (black &white) 600 DPI (color)

CombinationArt

Combination of halftone and lineart (e.g., halftones containingline drawing, extensive lettering,color diagrams)

EPS or JPG 1200 DPI

Editorial PolicyThe Journal of Laser Dentistry is devoted to providing the Academy and its members with comprehensive clinical, didactic andresearch information about the safe and effective uses of lasers in dentistry. All statements of opinions and/or fact are publishedunder the authority of the authors, including editorials and articles. The Academy is not responsible for the opinions expressedby the writers, editors or advertisers. The views are not to be accepted as the views of the Academy of Laser Dentistry unlesssuch statements have been expressly adopted by the organization. Information on any research, clinical procedures or productsmay be obtained from the author. Comments concerning content may be directed to the Academys main office by e-mail [email protected]

SubmissionsWe encourage prospective authors to follow JLDs Instructions to Authors before submitting manuscripts. To obtain a copy,please go to our Web site www.laserdentistry.org/press.cfm. Please send manuscripts by e-mail to the Editor at [email protected].

Disclosure Policy of Contributing Authors Commercial RelationshipsAccording to the Academys Conflict of Interest and Disclosure policy, authors of manuscripts for JLD are expected to discloseany economic support, personal interests, or potential bias that may be perceived as creating a conflict related to the materialbeing published. Disclosure statements are printed at the end of the article following the authors biography. This policy isintended to alert the audience to any potential bias or conflict so that readers may form their own judgments about the materialbeing presented.

Disclosure Statement for the Academy of Laser DentistryThe Academy of Laser Dentistry has no financial interest in any manufacturers or vendors of dental supplies.

Reprint Permission PolicyWritten permission must be obtained to duplicate and/or distribute any portion of the Journal of Laser Dentistry. Reprints maybe obtained directly from the Academy of Laser Dentistry provided that any appropriate fee is paid.

Copyright 2008 Academy of Laser Dentistry. All rights reserved unless other ownership is indicated. If any omission or infringementof copyright has occurred through oversight, upon notification amendment will be made in a future issue. No part of this publica-tion may be reproduced or transmitted in any fom or by any means, individually or by any means, without permission from thecopyright holder.

The Journal of the Academy of Laser Dentistry ISSN# 1935-2557.

JLD is published quarterly and mailed nonprofit standard mail to all ALD members. Issues are also mailed to new memberprospects and dentists requesting information on lasers in dentistry.

Advertising Information and RatesDisplay rates are available at www.laserdentistry.org/press.cfm and/or supplied upon request. Insertion orders and materials shouldbe sent to Bill Spilman, Innovative Media Solutions, P.O. Box 399, Oneida, IL 61467, 877-878-3260, fax: 309-483-2371, [email protected]. For a copy of JLD Advertising Guidelines go to www.laserdentistry.org/press_advguide_policy.cfm.The cost for a classified ad in one issue is $50 for the first 25 words and $2.00 for each additional word beyond 25. ALD membersreceive a 20% discount. Payment must accompany ad copy and is payable to the Academy of Laser Dentistry in U.S. funds only.Classified advertising is not open to commercial enterprises. Companies are encouraged to contact Bill Spilman for information on dis-play advertising specifications and rates. The Academy reserves the right to edit or refuse ads.

Editors Note on Advertising: The Journal of Laser Dentistry currently accepts advertisements for different dental laser educational programs. Not all dental laser educationalcourses are recognized by the Academy of Laser Dentistry. ALD as an independent professional dental organization is concerned that coursesmeet the stringent guidelines following professional standards of education. Readers are advised to verify with ALD whether or not specificcourses are recognized by the Academy of Laser Dentistry in their use of the Curriculum Guidelines and Standards for Dental Laser Education.

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E D I TO R S V I E W

Last month we had articles thatdescribed how light, including laserlight, can be used in everydaydental practice. The article on laserfluorescence for caries detectiondescribed just one of the novel newtechniques that are becoming avail-able. This month a review ofseveral other techniques ispresented. The bottom line is thatwe must understand how each ofthese instruments works so that wecan make an assessment of whatthe results mean for our patients.There is no step-by-step cookbookwith recipes to work from. Thepractitioner must be able to inter-pret the output to best use theinformation.

Many dentists who use lasers intheir practice use them for ablationof dental hard tissues, for theremoval of decay, and for cavitypreparations. In this issue we havean applied research article thathelps us understand what theerbium lasers are doing. Again, abetter understanding of the toolsthat we have in our hands isessential for the best treatmentplan and the best outcome for ourpatients.

The case studies are presentedas examples of how to put intopractice the understanding thatthe authors have of the lasersthat they are using for thevarious tasks. Laser dentistry is

not the only way to tackle any ofthese clinical problems. However,each of the cases presenteddemonstrates an elegant use oflaser technology in clinical prac-tice. These articles cover the useof Er:YAG, Nd:YAG, and diodelasers for primarily soft tissueapplications. In every case theauthors have chosen the laserthat they considered, from theirunderstanding, to be the best onefor the task at hand.

We are all dental professionals,each with our own skills and expe-rience. The common message thatruns through all of the articles inthis issue is that we must under-stand what we are doing in clinicaldentistry in order to decide on thelaser, or light source to use, and tointerpret what is happening as weuse it. Our education and experi-ence together must guide us to dothe very best that we can for theoral and general health of ourpatients.

In conclusion, I looked back onmy editorial from the last issue andI find it worth repeating the endingstatement: We must all becontinual learners and work outhow to apply our learning to what-ever we do each day.

Please enjoy this issue of thejournal. Feel free to e-mail me withsuggestions, criticisms, or compli-ments at [email protected].

A U T H O R B I O G R A P H YDr. John D.B. Featherstone isProfessor of Preventive andRestorative Dental Sciences andInterim Dean in the School ofDentistry at the University ofCalifornia, San Francisco (UCSF).He has a PhD in chemistry fromthe University of Wellington (NewZealand). His research over thepast 33 years has covered severalaspects of cariology (study of toothdecay) including fluoride mecha-nisms of action, de- andremineralization of the teeth,apatite chemistry, salivary dysfunc-tion, caries (tooth decay)prevention, caries risk assessment,and laser effects on dental hardtissues with emphasis on cariesprevention and early cariesremoval. He has won numerousnational and international awardsincluding the T.H. Maiman awardfor research in laser dentistry fromthe Academy of Laser Dentistry in2002, and the Norton Ross Awardfor Clinical Research from theAmerican Dental Association in2007. In 2005 he was honored asthe first lifetime honorary memberof the Academy of Laser Dentistry.Dr. Featherstone has published over200 papers. He is the editor-in-chiefof the Journal of Laser Dentistry.

Disclosure: Dr. Featherstone has nopersonal financial interest in anycompany relevant to the Academy ofLaser Dentistry. He consults for, hasconsulted for, or has done researchfunded or supported by Arm &Hammer, Beecham, Cadbury, GSK,KaVo, NovaMin, Philips Oralcare,Procter & Gamble, OMNII OralPharmaceuticals, Oral-B, Wrigley, andthe National Institutes of Health.

Featherstone

Understanding Our Laser Tools to Better Serve Our PatientsJohn D.B. Featherstone, MSc, PhD, San Francisco, CaliforniaJ Laser Dent 2008;16(1):5

SY N O P S I S

John Featherstone, editor-in-chief, describes some of the highlights of

this issue of the Journal of Laser Dentistry, illustrating how we must

understand what we are doing to better serve our patients.

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COV E R F E AT U R E

Karlsson and Tranus

Supplementary Methods for Detection and Quantification of Dental CariesLena Karlsson, RDH; Sofia Tranus, DDS, PhD

Department of Cariology and Endodontology, Institute of Odontology, Karolinska Institute,

Huddinge, SwedenJ Laser Dent 2008;16(1):6-14

I N T R O D U C T I O NOur efforts to make the concept ofcaries prevention popular, and topreserve the dentition into old ageare continuously successful.1-5

However, despite the dramaticdecline in dental caries, particu-larly in industrialized countriesand among children and youngadults, the disease persists, albeitwith highly skewed distribution.6-7

The following major changes haveoccurred in the pattern of thedisease: progression of enamelcaries is now slower, and allowspreventive intervention before irre-versible destruction of toothsubstance. There is also apronounced reduction in lesiondevelopment on the smoothsurfaces, which are readily acces-sible to fluoride.8-11 Diagnostictechniques to support appropriateclinical decisions about manage-ment of the individual lesion,whether invasive therapy or a moreconservative, noninvasive approachis indicated,12 are predominantlybased on subjective interpretationof visual information: visual inspec-tion, bitewing radiography, and theuse of a dental explorer.Longitudinal monitoring of lesionshas been hampered by the lack ofappropriate diagnostic techniques,

i.e., techniques of high sensitivityand specificity that reflect the slowlesion progression. The aim is toarrest or reverse the diseaseprocess, and to intervene beforeoperative restorative dentistry isneeded.

Objective, reliable quantitativedata on the outcome of thisstrategy, i.e., lesion response topreventive measures, would allowflexibility in selecting interventionappropriate for the individualpatient, before lesion progression toa stage requiring expensive inva-sive therapy. Optimal dental careand treatment will increasinglyinvolve a shift of emphasis and achange of the education andtraining of oral health personnel,and dental providers need to keepabreast of new approaches andtechnological advances for diag-noses and therapies of dentalcaries. In this context, there is aneed for complementary methodsfor detection and quantification ofdental caries. There are certainrequirements that should to be metby the methods; they have to meetall safety regulations; detect early,shallow lesions; differentiatebetween shallow and deep lesions;give a low proportion of false posi-tive readings; present data in a

quantitative form so that activitycan be monitored; be precise so thatmeasurements can be repeated byseveral operators; be cost-effectiveand user-friendly. Clinically appli-cable methods for detection of avery early phase of mineral lossand quantification of caries lesionshave emerged. In this paper, somenovel and commercially availablesupporting caries detectionmethods will be summarized; Fiber-Optic Transillumination, DigitalImaging Fiber-Optic Transillumin-ation, Laser Fluorescence,Quantitative Light-Induced

SY N O P S I S

This article reviews the modes of action and clinical application of

novel caries detection methods including digital imaging fiber-optic

transillumination, laser fluorescence, quantitative light-induced laser

fluorescence, and alternating current impedance spectroscopy.

A B ST R AC TThere is a need for objective instru-mental caries detection methods tosupplement traditional visualassessment by the clinician. Thesemethods should be used assupplements to aid in makingappropriate decisions about theclinical management of the indi-vidual lesion, such as whether touse invasive therapy or a moreconservative, noninvasive approach.Objective, reliable, quantitativemeasures for longitudinal moni-toring of lesion response topreventive measures would allowflexibility in selecting interventionappropriate to the individualpatient, before lesion progressionreaches a stage requiring invasivetherapy. This paper reviews somenovel and commercially availablecaries detection methods: Fiber-Optic Transillumination, DigitalImaging Fiber-Optic Transillumina-tion, Laser Fluorescence,Quantitative Light-inducedFluorescence, and Electronic CariesMeasurement.

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Karlsson and Tranus

Fluorescence, and Electronic CariesMeasurement.

T H E M ET H O D SFiber-Optic Transillumination(FOTI)FOTI is a technique that uses lighttransmission through the tooth13-18

and has been available on themarket for more than 40 years, incontrast to the other more novelmethods described below that haveonly recently been developed. FOTIis based on the theory thatdemineralized dental hard tissuesscatter and absorb light more thansound tissue. White, cold light istransmitted from a light sourcethrough an optical fiber to a hand-piece with a thin probe that isapplied to the tooth surface. Figure1 shows the clinical FOTI setup. Itdetects and visualizes the carieslesions, so demineralized regionsappear darker compared to thesurrounding sound tissue, and thecontrast between sound andcarious tissue is then used fordetection of lesions on occlusal,approximal, and smooth surfaces,on enamel as well as dentin. Thistechnique relies on the human eyeas the detector and is not quantita-tive. The majority of the FOTIstudies show the same tendency asthe well-performed in vitro studyon occlusal surfaces by Grossman

et al.,19 which showed low sensi-tivity (0.39) and high specificity(0.92), i.e., the risk for false positiveobservations was low, and the riskfor missed carious lesions was high.There is a need for training andcalibration of operators, but fewclinical factors influence the read-ings.

Clinical perspective: FOTI isessentially a refinement of tradi-tional visual observation that canenhance caries detection by atrained and experienced clinician,but is not quantitative and has thesame limitations as traditionalvisual methods for assessing lesionextent and following lesions overtime.

Digital Imaging Fiber-OpticTransillumination (DIFOTI)A recently marketed method basedupon the same principles as FOTIis the digitized DIFOTI method. Inthis method the white light isdelivered through an optical fibervia a specially designed handpiecethat has a mirror on the oppositeside of the tooth, thereby chan-nelling the image back to a digitalcamera and visualizing the imageon a monitor via a computersystem. An ordinary computersetup with specially designed soft-ware creates a real-time image ofthe illuminated tooth on thecomputer screen. The images canbe stored for later retrieval andcomparative examination. Twodisposable mouthpieces are avail-able, one for proximal and one forocclusal surfaces, in an adult aswell as a pediatric size. TheDIFOTI method is still qualitative.Figure 2 shows a DIFOTI image ofa molar occlusal surface. As can beseen tooth defects are readily visu-alized, such as the unusualmorphology in this image. As withregular FOTI, the users level ofexperience is essential. Onlylimited research has so far beenperformed.20-22

Clinical perspective: TheDIFOTI technique essentially picks

up surface scattering of the visual-izing light and readily indicates thepresence of very early cariouslesions, cracks, or imperfections inthe tooth surface. From a clinicalperspective, however, this informa-tion is very limited in itsusefulness. The method gives noindication of lesion depth, severity,or progress over time, and cannotbe used in the determination ofhow deep the lesion is and whethersurgical intervention is necessary.This problem was highlighted inthe recent study by Young andFeatherstone.22

Laser Fluorescence (LF)When a caries lesion in enamel anddentin is illuminated with red laserlight ( = 655 nm), organic mole-cules that have penetrated porousregions of the tooth, especiallymetabolites from oral bacteria, willcreate an infrared (IR) fluorescence.The enamel is essentially trans-parent to red light. The IRfluorescence is believed to originatefrom porphyrins and relatedcompounds from oral bacteria.These molecules are chiefly respon-sible for the absorption of red light.23

The laser instrument,DIAGNOdent (DD) (KaVo DentalGmbH, Biberach, Germany), isbased on research by Hibst andGall,24 was introduced in the late1990s, and is today marketed in twoversions. Apart from smooth andocclusal surfaces, the latest version,

Figure 1: Clinical FOTI setup. There areseveral types of probes on the market.This illustrates a quite thick probe.

Figure 2: An occlusal surface on a molar,viewed through DIFOTI. The tooth is illu-minated from the buccal surface. Darkareas around the fissures indicate carieslesions.

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the DD-pen, also aims to readilyaccess approximal surfaces. There isas yet limited information on theusefulness of the latter device.

As described in a recent reviewby Hibst,23 red light from a 655-nmdiode is transmitted through anoptical fiber to a hand probe. Thislight beam is used to irradiate thetooth, with the red light transmit-ting readily through sound enamel.When the light reaches a cariouslesion and interacts with appro-priate organic molecules that havebeen absorbed into the porousstructure, the light is re-emitted asinvisible fluorescence in the near-infrared region. The emitted lightis channelled through the hand-piece to a detector and presented tothe operator as a digital number ona display (0-99). A higher numberindicates more fluorescence and byinference a more extensive lesionbelow the surface.

The first version of the LFdevice has shown good performanceand reproducibility for detectionand quantification of occlusal andsmooth surface carious lesions in invitro studies,25-27 but with somewhatmore contradictory results in vivo,both in the primary and permanentdentition.28-34 It has also been triedfor longitudinal monitoring of thecaries process, and for assessingthe outcome of preventive interven-tions.25,35-37 The DD-pen (Figure 3)might be a useful additional tool indetecting approximal caries, buthas so far only been evaluated inthree in vitro studies.38-40 Factorsthat may influence the outcome ofthe measurements in differentways are: presence of plaque,calculus and/or staining on thetooth surface,18,25 and the degree ofdehydration of tooth tissue.26 Thesystem detects fluorescent organicmolecules that can be present inany surface deposits, therebyreadily producing false positives.For measurements on occlusalsurfaces, it is also of great impor-tance that the tip is tilted over arange of several different angles to

access all relevant subsurfaceregions.

Clinical perspective: The LFdevice is a useful adjunct to tradi-tional visual examination,especially in occlusal surfaces, forthe detection of hidden lesionsbelow the surface. However, thedevice detects organic moleculesthat have penetrated into surfacedeposits or subsurface porosities,such as carious lesions. It does notdirectly detect demineralization.Results must be interpreted withcaution by understanding how thedevice works and how false positivereadings can be misleading. Thedigital number displayed indicatesthe amount of fluorescence, whichis not necessarily a measure oflesion size or depth.

Quantitative Light-Induced Fluorescence(QLF)The phenomenon of toothauto fluorescence haslong since been suggestedto be useful as a tool forthe detection of dentalcaries.41 Fluorescence is aproperty of some man-made and naturalmaterials that absorbenergy at certain lightwavelengths and emit

light at longer wavelengths. Anincreased porosity due to a subsur-face enamel lesion, occupied bywater, scatters the light either as itenters the tooth or as the fluores-cence is emitted, resulting in a lossof its natural fluorescence.Consequently the demineralizedarea appears opaque. The stronglight scattering in the lesion leadsto shorter light path than in soundenamel, and the fluorescencebecomes weaker. Bjelkhagen andSundstrm42 and later de Josselinde Jong et al.43 developed a tech-nique based on this opticalphenomenon, making the differencein fluorescence radiance betweenthe carious and sound tooth struc-ture quantitative. This has beentermed quantitative light-inducedfluorescence (QLF).

The QLF method can readilydetect lesions to a depth of approxi-mately 500 m. on smooth andocclusal enamel surfaces. In thecurrently marketed systems(Inspector Pro, Inspektor DentalCare, Amsterdam, TheNetherlands) the illuminationsystem consists of a 50-Wattmicrodischarge arc lamp equippedwith an optical bandpass filter witha peak intensity of 370 nm, trans-mitted through an optical fiberfrom the light source to a handpiecewith a micro CCD video camera. Ahigh-pass filter in front of thecamera blocks the excitation lighttogether with the ambient light, so

Figure 3: Approximal measurement withthe DIAGNOdent pen. The red laser lightcan be seen through the dental hardtissue.

Figure 4: Principal setup of the Quantitative Light-Induced Fluorescence method.

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that only wavelengths above 520nm are transmitted to the detector.Figure 4 shows the principal setupfor the QLF-technique.

The preferred image is capturedand saved by the operator bypressing a foot switch, and is laterprocessed. Details about the toothand the surface examined are setin the program, and the positionand orientation of the processedimage is thereafter automaticallystored in a preset pattern so thatwhen the patient comes back onrecall, a contour guides the oper-ator to the right position again. Theprogram offers an automatic repo-sitioning facility, which can be setat any level, and when correlationbetween the reference image andthe real-time image is satisfactory,it can be saved automatically. Thefluorescence image is firstconverted into a black-and-whiteimage so that thereafter the lesionsite can be reconstructed by inter-polating the grey level values inthe sound enamel around thelesion. The difference betweenmeasured and reconstructed valuesgives three quantities: F (averagechange in fluorescence, %), lesionarea (mm2), and Q (area x F), thelatter giving a measure of theextent and severity of the lesion.Figure 5 shows the analytical partof the QLF method, as calculatedby the specially designed software.

The QLF method has been testedin several in vitro,44-46 in situ,47 andin vivo43, 48-53 studies for smoothsurface caries lesions. The possi-bility of adapting the QLF methodfor occlusal caries diagnosis is underinvestigation54-55 as well as modifica-tion for detection and quantificationof secondary caries,56-58 but has yet tobe tested clinically. Application forquantification of dental fluorosishas also been investigated.59

Higham et al.60 concluded QLFhas the potential to detect, diag-nose, and longitudinally monitorocclusal caries and provide usefulinformation to the clinician withregard to the severity of the lesionand likely treatment. Eggertssonet al.61 reported good reproducibilityof QLF methods clinically withinter- and intra-examiner relia-bility greater than 0.95 aftertraining.

Factors that may influence theoutcome of the measurements are:presence of plaque, calculus and/orstaining,62 ambient light, daylightor office light, and the degree ofdehydration of tooth tissue.63 Thenewly designed handpieces on thecommercially available deviceshave largely overcome the ambientlight problems. Certain errors inthe capturing stage of the method,such as differences in x- or y-axis,or rotation of the image, may beadjusted during the analytical

stage of the method.The QLF method can

also measure and quan-tify the red fluorescence(RF) from microorgan-isms in plaque. The RFobserved in plaque canbe of use when moni-toring oral hygiene;removing infecteddentin; detecting aleaking sealant or cariesat the margin of arestoration. Two quanti-ties are obtained, R(average change in redfluorescence, %), andarea (mm2). So far there

are a very limited number ofstudies performed with thisfeature.64

Clinical perspective: The QLFsystem that has recently come onthe market (Inspektor Pro) inseveral countries can be used as aquantitative measure of enamellesions in smooth surfaces. It islikely that is will also be useful forocclusal surfaces but this has yet tobe proven. The sophisticatedcomputer-driven repositioningfeature enables lesion progressionor arrestment to be followed overtime. This system appears to be auseful adjunct to traditional visualexamination.

Electronic Caries Measurement(ECM) and Alternating CurrentImpedance SpectroscopyThe ECM technique is based on thetheory that sound dental hardtissue, especially the enamel, showsvery high electrical resistance orimpedance. Demineralized enamelbecomes porous, and the pores fillwith saliva, water, microorganisms,etc. The more demineralized thetissue, the lower the resistancebecomes. In the impedance meas-urement system a circuit of a veryweak alternating current is closedthrough the patient. From thedevice, a fiber leads to a probe,which is placed on the site that isto be measured.

Figure 6: Clinical use of Electronic CariesMeasurement (ECM).

Figure 5: The analytical interface of the QLF method.The lesion is color-coded so that the operator can get aquick impression of the area and the depth.

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Figure 6 shows clinical use of anElectronic Caries Measurementdevice. The patient holds a ground-unit in the hand, and from theground-unit, a fiber leads back tothe device. Compressed air that isled through the probe isolates themeasuring site from thesurrounding saliva. The result ofthe measurement is presented on adisplay as a number between 1 and13, and the higher the number, thedeeper the lesion.

Site-specific measurements havebeen evaluated in a number of invitro studies65-71 and in vivostudies.72-73 The reported sensitivityfor ECM in detecting dentinalcaries lesions of permanentpremolar and molar teeth rangesfrom 0.93 to 0.95, and the speci-ficity ranges from 0.53 to 0.70, inclinical studies, which gives amoderate risk for false positivereadings, and a low risk of missedcarious lesions. Surface-specificelectrical conductance measure-ments have been investigatedunder in vitro conditions,74 whichshowed moderate sensitivity andspecificity. Factors that may influ-ence the outcome of themeasurements are the degree ofdehydration of tooth tissue,75 thedegree of maturation of theenamel,76 and temperature varia-tions.77

Another impedance/conduc-tance-based method is AlternatingCurrent Impedance Spectroscopy(ACIST). It is based on the sameassumptions about electricalcircuits and dental hard tissues asthe ECM instrument. Apart fromthe forward conductance (resist-ance values, representingcontinuous conduction/diffusionpathways) it also measures trans-verse conductance (capacitativeconductance pathways). This couldgive more information than theECM.78-79 A commercially manufac-tured impedance measurementdevice has recently come on themarket in the United Kingdom(CarieScan, IDMoS PLC, Dundee,

United Kingdom) and is likely toreach the United States in the nearfuture.

Clinical perspective: The elec-trical conductance or impedancemeasurement devices have hadlimited success in the past. Thenew ACIST system shows consider-able promise as a method withgood ability to detect lesions with alow level of false positives.However, the device gives alesion/no lesion answer rather thanan image, extent of the lesion, posi-tion of the lesion measure. Thistechnique is likely to be a usefuladjunct to traditional examinationprovided the clinician uses theinformation wisely in combinationwith other observations to deter-mine an intervention or restorativetreatment plan.

D I SC U SS I O NQuantitative dental caries detec-tion methods may take subjectiveinterpretations of visual, tactile,and radiographic methods toevidence-based clinical practice. Ashift from traditional diagnosticmethods to advanced and moresensitive methods will improvecaries diagnostic routines andhence the dental care and treat-ment for our patients benefit:minimize the use of unavoidablehazards of ionizing radiation,detect caries in an early stage,obtain a more precise estimation oflesion depth and severity, reveal adentinal lesion obscured by super-imposed sound tissue, monitoringde- or remineralization, evaluatethe outcome of different preventivestrategies, and detect and quantifybacterial activity.

The caries detection methodsreviewed in this article meetgeneral clinical needs and althoughsignificant promise is seen in thesetechniques, there is not enoughevidence currently available torecommend any one of them as asubstitute for conventionalmethods. However, each of themcan be valuable in its own way, as

summarized above as a supplementto traditional methods. Each of thenew methods reviewed brings addi-tional information about lesions ina manner specific to the technologyused.

Nevertheless, traditionalmethods of caries assessment,which discriminate lesions at thecavitation stage, are not alwaysclinically appropriate, and are obso-lete for clinical research requiringdetection of a very early phase ofmineral loss, which allow a reduc-tion in the duration ofexperimental periods and thenumber of subjects required, savingboth time and money. To developand test a new medical technicaldevice is a long-term commitment;it takes time, scientific research,and evidence from the time of thefirst idea to a validated commer-cially available device, and eventhough laboratory findings showstrong results, caution is indicatedwhen extrapolating these into clin-ical conditions.

The QLF method is today themost promising technology of thosecurrently on the market, due to itsclose correlation to the enamelmineral content, but with limita-tions such as the inability to detectapproximal (and occlusal) carieslesions, and dentinal caries. One ofthe upcoming methods and devices,based on different physical theoriesthat is expected to appear on themarket in the future is OpticalCoherence Tomography (OCT)which can produce two- or three-dimensional images ofdemineralized regions in dentalenamel. When a tooth with acarious lesion is illuminated withinfrared light at 1310 nm, OCTtechnology can produce a quantita-tive image of the subsurface lesionto the full depth of the enamel.80-81

The OCT method is, however, stillyet far from a marketed device foreveryday use in the dental office.

All improvements requirechange, but not all change isimprovement. Evidence-based care

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is by definition the conscientious,explicit, and judicious use of thecurrent best evidence in makingdecisions about the care of indi-vidual patients, which includesintegrating individual clinicalexpertise with the best availableexternal clinical evidence.82 It istherefore important to emphasizethe need for clinical trials to supportcritical appraisal and decisionmaking in using these techniques,by theory and empirical evidence.

In summary, there are severaldevices currently on the marketand more to come that can be usedby the clinician as valuable supple-ments to the traditional cariesdetection and assessment methods.All of the new methods require abasic understanding of how theywork so that the results can becorrectly interpreted for the benefitof the patient, especially to aid inthe decision as to how to treatmentplan, which lesions can be reversed,which chemical therapy should beused, how to assess success or not,and when to intervene withrestorative work.

A U T H O R B I O G R A P H I ESLena Karlsson is a registereddental hygienist and a PhD studentat Karolinska Institute, Sweden.She works as a lecturer at theInstitute of Odontology, unit ofCariology and Endodontics, and isinvolved in the dental hygienistand the dental student educationalprograms. In the late 1990s shebegan to undertake research in thefield of diagnosis, prevention, andmanagement of dental caries witha focus on the interaction betweenlaser light and dental hard tissues,supervised by Professor BirgitAngmar-Mnsson. Today she is oneof Dr. Sofia Tranuss doctoralstudents and her thesis workinvolves studies of differentmethods for detection and quantifi-cation of carious lesions at theirearliest stages. She may becontacted by e-mail [email protected].

Disclosure: Lena Karlsson hasreceived research funding from inde-pendent organizations including theKarolinska Institutet, the SwedishPatent Revenue Fund for Research inPreventive Dentistry, and the SwedishDental Society. She has also receivedresearch funding or free use of tech-nical devices from Inspektor ResearchSystems BV (The Netherlands), KaVoScandinavia AB (Sweden), and KaVoDental GmbH (Germany).

Dr. Sofia Tranus is a seniorlecturer in the Department ofOdontology at the KarolinskaInstitute in Stockholm, Sweden.She has spent the past 10 yearsdeveloping and testing new tech-niques for detection andquantification of dental caries. Dr.Tranus completed her PhD in2002 at the Karolinska Institute,with her thesis entitled Clinicalapplication of QLF andDIAGNOdent Two new methodsfor quantification of dental caries.Currently, she is on a temporary 2-year assignment at SBU TheSwedish Council on TechnologyAssessment in Health Care. Dr.Tranus may be contacted by e-mail at [email protected].

Disclosure: Dr. Tranus has receivedresearch funding from independentorganizations including theKarolinska Institutet, the SwedishPatent Revenue Fund for Research inPreventive Dentistry, and the SwedishDental Society. She has also receivedunrestricted research funding fromInspektor Research Systems BV (TheNetherlands), KaVo Scandinavia AB(Sweden), and KaVo Dental GmbH(Germany).

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59. Pretty IA, Tavener JA, Browne D,Brettle DS, Whelton H, Ellwood RP.Quantification of dental fluorosisusing fluorescence imaging. CariesRes 2006;40(5):426-434.

60. Higham SM, Smith PW, Pretty IA.Development of an occlusal cariesindex for quantitative light-inducedfluorescence (QLF). In: Stookey GK,editor. Early detection of dentalcaries III: Proceedings of the 6thannual Indiana conference.Indianapolis: Indiana University,School of Dentistry, 2003:195-212.

61. Eggertsson H, Ferreira-Zandon AG,Ando M, Gonzlez-Cabezas C,Fontana M, Martinez-Mier EA,Waskow-Chin JR, Jackson RD,Eckert GJ, Stookey GK, Zero DT.Reproducibility of in vitro and clin-ical examinations with QLF(Quantitative Light-InducedFluorescence). Developing guide-lines for imaging and analyzingQLF images, and a process fortraining examiners. In: Stookey GK,editor. Early detection of dentalcaries III: Proceedings of the 6thannual Indiana conference.Indianapolis: Indiana University,School of Dentistry, 2003:213-228.

62. Al-Khateeb S, Exterkate RAM, deJosselin de Jong E, Angmar-Mnsson B, ten Cate JM.Light-induced fluorescence studieson dehydration of incipient enamellesions. Caries Res 2002;36(1):25-30.

63. Angmar-Mnsson B, Al-Khateeb S,Tranus S. Quantitative light-induced fluorescence: Currentresearch. In: Stookey GK, editor.Early detection of dental caries II:Proceedings of the 4th annualIndiana conference. Indianapolis:Indiana University, School ofDentistry, 2000:203-217.

64. van der Veen MH, Thomas RZ,Huysmans MC, de Soet JJ. Red auto-

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fluorescence of dental plaque bacteria.Caries Res 2006;40(6):542-545.

65. White GE, Tsamtsouris A, WilliamsDL. Early detection of occlusalcaries by measuring the electricalresistance of the tooth. J Dent Res1978;57(2):195-200.

66. Verdonschot EH, Wenzel A, TruinGJ, Knig KG. Performance of elec-trical resistance measurementsadjunct to visual inspection in theearly diagnosis of occlusal caries. JDent 1993;21(6):332-337.

67. Ricketts DN, Kidd EA, Liepins PJ,Wilson RF. Histological validation ofelectrical resistance measurementsin the diagnosis of occlusal caries.Caries Res 1996;30(2):148-155.

68. Ekstrand KR, Ricketts DN, KiddEA. Reproducibility and accuracy ofthree methods for assessment ofdemineralization depth of theocclusal surface: An in vitro exami-nation. Caries Res1997;31(3):224-231.

69. Ashley PF, Blinkhorn AS, DaviesRM. Occlusal caries diagnosis: An invitro histological validation of theElectronic Caries Monitor (ECM)and other methods. J Dent1998;26(2):83-88.

70. Wicht MJ, Haak R, Sttzer H,Strohe D, Noack MJ. Intra- andinterexaminer variability andvalidity of laser fluorescence andelectrical resistance readings on

root surface lesions. Caries Res2002;36(4):241-248.

71. Khnisch J, Heinrich-Weltzien R,Tabatabaie M, Stsser L, HuysmansMC. An in vitro comparison betweentwo methods of electrical resistancemeasurement for occlusal cariesdetection. Caries Res2006;40(2):104-111.

72. Rock WP, Kidd EAM. The electronicdetection of demineralisation inocclusal fissures. Br Dent J1988;164(8):243-247.

73. Verdonschot EH, Bronkhorst EM,Burgersdijk RCW, Knig KG,Schaeken MJM, Truin GJ.Performance of some diagnosticsystems in examinations for smallocclusal carious lesions. Caries Res1992;26(1):59-64.

74. Huysmans MC, Longbottom C,Hintze H, Verdonschot EH. Surface-specific electrical occlusal cariesdiagnosis: Reproducibility, correla-tion with histological lesion depth,and tooth type dependence. CariesRes 1998;32(5):330-336.

75. Yukizaki H, Kawaguchi M, EgashiraS, Hayashi Y. Relationship betweenthe electrical resistivity of enameland the relative humidity. ConnectTissue Res 1998;38(1-4):53-57,discussion 73-79.

76. Schulte A, Gente M, Pieper K.Posteruptive changes of electricalresistance values in fissure enamel

of premolars. Caries Res1999;33(3):242-247.

77. Huysmans MC, Longbottom C,Christie AM, Bruce PG, Shellis RP.Temperature dependence of the elec-trical resistance of sound andcarious teeth. J Dent Res2000;79(7):1464-1468.

78. Longbottom C, Huysmans MC, PittsNB, Los P, Bruce PG. Detection ofdental decay and its extent usinga.c. impedance spectroscopy. NatMed 1996;2(2):235-237.

79. Huysmans MC, Longbottom C, PittsNB, Los P, Bruce PG. Impedancespectroscopy of teeth with andwithout approximal caries lesions An in vitro study. J Dent Res1996;75(11):1871-1878.

80. Fried D, Xie J, Shafi S, FeatherstoneJD, Breunig TM, Le C. Imagingcaries lesions and lesion progressionwith polarization sensitive opticalcoherence tomography. J BiomedOpt 2002;7(4):618-627.

81. Jones RS, Darling CL, FeatherstoneJD, Fried D. Imaging artificialcaries on the occlusal surfaces withpolarization-sensitive optical coher-ence tomography. Caries Res2006;40(2):81-89.

82. Sackett DL, Rosenberg WM, GrayJA, Haynes RB, Richardson WS.Evidence based medicine: What it isand what it isnt. BMJ1996;312(7023):71-72.

Karlsson and Tranus

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SC I E N T I F I C R E P O RT

Effect of Er,Cr:YSGG Laser on Human DentinCollagen: A Preliminary StudyEleftherios-Terry Farmakis, DDS, MDSc, PhD1; Konstantinos Kozyrakis, DDS, PhD2; Evangelos G.

Kontakiotis, DDS, PhD3; Kouvelas Nikolaos DDS, PhD41Fellow Researcher, Department of Endodontics, Dental School, University of Athens, Greece; 2Lecturer, Department of Endodontics,

Dental School, University of Athens, Greece; 3Assistant Professor, Department of Endodontics, Dental School, University of Athens,

Greece; 4Associate Professor, Dept of Pediatric Dentistry, Dental School, University of Athens, Greece.

J Laser Dent 2008;16(1):15-20

I N T R O D U C T I O NSince the discovery of lasers in1960, much research has been donein order to investigate the interac-tion of lasers with the dentaltissues.1-2 The early dental lasersfor use with hard dental tissueapplications often produced a char-ring effect. A few years ago, a ClassIV Erbium Laser was cleared bythe U.S. Food and DrugAdministration (FDA) for use indentistry. This type of laser(Er,Cr:YSGG) uses a crystal whosemain element is erbium (a rareearth element), in addition to smallportions of chromium, yttrium,scandium, gallium, and garnet.This crystal when irradiated emitsa characteristic wavelength of 2780nm that falls within the absorptionband of water.3-5

One of the earlier possible expla-nations, proposed by themanufacturer, for the action of theEr,Cr:YSGG laser on dental hardtissues has to do with the interac-tion of this specific laserwavelength with the water spray ofthe laser handpiece. It has beensuggested that when water dropletsare introduced into theEr,Cr:YSGG laser beam, that thewater droplets explode violently

outwards, due to the energyabsorption, thus creating a plasmaexpansion which drives the waterdroplets to supersonic velocity. Theexpression of this phenomenon is aproduction of a pressure of 400MPa and velocities up to 1000m/sec from energized waterdroplets.6 When this stream ofwater jet is striking the target, itsupposedly has enough power todislodge material but with a veryaccurate cutting.7 It has beensuggested that water is the cuttingagent; and in addition that harddental material that is dislodged,once incorporated into the stream,could act as abrasive particles, thusincreasing the efficiency of thecutting field. This abrasive waterjet (AWJ) is speculated to becapable of removing hard dentaltissues but without the carboniza-tion effect associated with othertypes of lasers, due to its indirectaction. Actually, the temperature atthe operating field is reduced,8-9

something that might be expecteddue to the cooling effect of water.

However, it has recently beenproposed that the action of theEr,Cr:YSGG laser is similar to theEr:YAG, since their wavelengthsare similar (2780 nm for the

Farmakis et al.

A B ST R AC TObjective: The objective of thisstudy was to determine the alter-ations of human dentin proteins(mainly collagen) following theuse of an Er,Cr:YSGG laser.Materials & Methods: Fifteenhuman dentin sections werestudied in three equal groups. Halfof the surface was irradiated usingan energy density of 88 J/cm2 forgroups A and C, and 150 J/cm2 forgroup B. In addition, group C wasetched for 15 seconds with 37%phosphoric acid. All sections werethen immersed in 5% ninhydrinsolution for 3 hours and thenexamined by light microscopy forcollagen assessment. Results: Ingroups A and B the controluntreated surfaces appeared in ablue-reddish color. In group A, thetreated surfaces showed circularwhite areas surrounded by deepblue rings and under magnifica-tion the dentin appearedroughened and smear layer-free.In group B, the treated areasshowed a roughened surface withno coloration. In group C, both theetched-only and the irradiated andetched surfaces showed a lightercoloration compared to control.Conclusions: From this prelimi-nary study, it is suggested thatthere was a severe change inhuman dentin collagen andcreation of a roughened dentinsurface following the use of thislaser. The higher the energy, thegreater the effect. Fewer changesoccurred after the use of etchantonly.

SY N O P S I SThis article reports a study that illustrates how the collagen is

affected during ablation of dentin by an Er,Cr:YSGG laser, at clinically

relevant fluences.

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Er:YAG, 2940 nm for theEr,Cr:YSSG), both falling withinthe water absorption band.Accordingly they have similarabsorption parameters in the harddental tissues.10

The most recent explanation forits action is the interaction of thisspecific laser wavelength withhydrated dentin. Since this wave-length is absorbed very well by thewater content of dentin and also bythe hydroxyapatite mineral, thewater is heated and finally vapor-ized; the vapors remain inside thedental tissues until the pressurebuilding up in the dental hardtissues is enough to disrupt theirintegration, causing micro-explo-sions, thereby ejecting dentinparticles (water-induced ablation).11

In cavity preparations made bydental burs, bonding of resin toenamel is achieved via micro-mechanical retention on theroughened surface, whereas theretention to dentin is based mainlyon the hybrid layer formation andto a lesser degree to the microme-chanical retention offered by theresin tags embedded in dentin.12-13

In cavities prepared byEr,Cr:YSGG lasers, the associatedmicroroughness on both enameland dentin does not require achange of approach to resinbonding to the enamel. However,the resulting alteration of collagenmay lead to the formation of aninferior hybrid layer zone due toincomplete penetration of thecollagen fibrils by the hydrophilicprimers and resin monomers.14 Inthis case, the resin-dentin bond isfavored by resin tag formation.15

The objective of this work was toinvestigate the possible alterationsof human dentin proteins (mainlycollagen) following irradiation byan Er,Cr:YSGG laser underdifferent clinically relevantsettings. These changes in dentincould affect the hybrid layer forma-tion and the subsequent dentinbonding to resin composite restora-tive materials.

M AT E R I A LS A N DM ET H O D SFifteen standardized dentinsections (each 2 mm thick) wereprepared from sound humanmolars that had been stored insterile saline, until they were used.From each tooth, a single disc wasobtained by using a low-speed saw(IsoMet, Buehler Ltd., Lake Bluff,Ill., USA) under tap water cooling.The cutting plane was parallel tothe occlusal surface of the toothand in most cases the sections didnot interfere with the pulp horns. Agroove was made on one side ofeach section, dividing the surfaceinto two parts. Finally the sectionswere randomly distributed intothree groups.

The Er,Cr:YSGG laser hand-piece (Millennium, BiolaseTechnology, Inc., San Clemente,Calif., USA) was securely mountedon a stand so the beam would fallvertically on the section surface ata distance of 5 mm from the end ofthe tip. The sapphire tip used was0.7 mm in diameter. Then eachsection was mounted on a micro-scope observation glass slide andmoved manually at a rate ofapproximately 5 mm/sec in asweeping motion, simulating thehand movement during cavitypreparation.

In groups A and B, one half ofeach section surface was treatedwith the settings suggested by themanufacturer for treating dentinand enamel respectively. Settingsand calculated energy densities areshown in Table 1. Groups A and Cwere irradiated at 88 J/cm2, andGroup B at 150 J/cm2.

In group C, half of the surface

was treated with dentin-treatinglaser irradiation settings and thenboth halves (the whole surface)were etched for 15 seconds with37% phosphoric acid (Enamel PrepEtching Gel, Ivoclar Vivadent A.G.,Schaan, Liechtenstein) applied by adisposable brush. This procedurewas repeated on all five sections ofgroup C, simulating the etchingprocedure that usually takes placebefore the use of composite resinfilling materials along with the useof priming and bonding agents.

The main question was: Do allor any of these procedures affect

Farmakis et al.

Table 1: Er,Cr:YSGG laser parameters based on the manufacturer* recom-mendation for treating dentin and enamelParameter Dentin Enamel

Power 3.5 Watts 6 Watts

Pulse Energy 175 mJ 300 mJ

Frequency 20 Hz 20 Hz

Energy Density 88 J/cm2 150 J/cm2

*Millennium, Biolase Technology, Inc., San Clemente, Calif., USA

Figure 1: A typical deep blue-reddishappearance of control dentin area afterthe use of 5% aqueous ninhydrin solution

Figure 2: A laser-treated specimen usingthe settings for dentin (Group A) after theuse of 5% aqueous ninhydrin solution

dentin collagen, and to whatextent?

The chosen method for moni-toring was the use of 5% ninhydrinsolution. Ninhydrin [2, 2-dihy-droxy-1H-indene-1, 3(2H)-dione or2,2-dihydroxy-1,3-indanedione](Merck & Co, Inc., WhitehouseStation, N.J., USA) comes as amonohydrate molecule, formingpale yellow prisms that freelydissolve in water, producing ayellow-colored solution.16 Whenused as a reagent, upon the pres-ence of free -amino acids andcarboxyl groups (which in this casecome from human dentin proteins,mainly collagen), it yields a blue-reddish color. The degree ofcoloration is not only a qualitativemethod but it can also become asemi-quantitative one with the useof a spectroscope. Thus, changes

can be precisely detected and meas-ured, compared to a control of agiven substrate.16

After all procedures werecompleted, according to theprotocol, all sections wereembedded in 5% aqueous ninhydrinsolution for 3 hours. Then allsections were examined by lightmicroscopy (50X up to 1000Xmagnification) and photographswere taken.

R ES U LTSAll control areas of groups A and B,plus the back side of all sections(groups A, B, and C), had the sameappearance: deep blue-reddishcolor, demonstrating that afterdentin was cut with a diamond saw,free -amino and carboxyl groupswere exposed, originating mainlyfrom the dentin collagen (Figure 1).

In the laser-irradiated area ofgroup A macroscopically, thetreated area looked pitted (Figure2). At 100X (Figure 3) and 200Xmagnification (Figure 4), smallcircular craters were observed,which were white centrally, andsurrounded by deep blue rings. Athigher magnification (500X), thedentin surface was observed to beroughened (Figure 5), and at 1000Xmagnification appeared to be smearlayer-free (Figure 6).

In the laser-irradiated area ofgroup B, macroscopically, a gener-ally roughened dentin with nocoloration was observed (Figure 7).At higher magnification (500X), thesurface appeared aggressivelyroughened compared to the treatedarea of group A, but the surfacewas smear layer-free (Figure 8).

In the sections of group C, both

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Figure 3: A laser-treated specimen using the settings for dentin(Group A) after the use of 5% aqueous ninhydrin solution (100Xmagnification)

Figure 5: Roughened dentin surface after laser irradiation withthe settings for treating dentin (Group A, 500X magnification)

Figure 6: Roughened dentin surface after laser irradiation withthe settings for treating dentin (Group A, 1000X magnification).The absence of smear layer is noticeable

Figure 4: A laser-treated specimen using the settings for dentin(Group A) after the use of 5% aqueous ninhydrin solution (200Xmagnification)

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Farmakis et al.

the etched-only and the irradi-ated/etched areas appeared similarin coloration: not as densely coloredas the control area (Figure 9). Inthe areas that were both laser-irra-diated and etched (500X), thesurface appeared to be like thelaser irradiation-only group, onlymuch smoother, with the residualsof the etching procedure apparentin some areas (Figure 10).

D I SC U SS I O NEarlier studies with other types oflasers showed carbonizations alongwith crack lines due to thermaleffects during the treatment ofdental hard tissues.1-2 The erbiumlaser energy is primarily absorbedby the water molecules, convertedinto kinetic energy, resulting in nocarbonization of the irradiated

surface and no thermal damage topulp with clinically relevant energylevels.

In this study, the observationthat the treated dentin surfaceswere smear layer-free was inagreement with other studies.17-18

Collagen alteration was directlyrelated to the energy level used.At the higher energy level studied,more alteration of collagen wasobserved. Collagen alterationswere similarly observed on thesurfaces following etching. Otherstudies that examined the alter-ation of dentin collagen after acidetching reported a denaturation ofcollagen,17 a removal of peptides,changes in collagen conformationin situ, and a collapse of the

fibrils.19 This dentin surfacechange, prior to bonding agentapplication, did not seem to nega-tively affect the formation of asound hybrid layer. In our studythe condition of collagen fibrils ofacid-etched or laser-treated dentinwas not tested. More research isneeded to evaluate the morpholog-ical and structural changes of theremaining collagen and thequality of the resulting hybridlayer after the use of this laserunder the clinically relevantparameters used.

When the lower energy settingswere used, the creation of eachcrater was the effect of internalexplosion of vapors inside thedentin. It looked as though in thecenter of each crater, along withthe dentin removal, there was anarea that was free from -aminoand carboxyl groups, while at theperiphery there were remains ofcollagen. This could be explained bythe Gaussian profile distribution ofthe pulse energy.20 At the higherpower settings the treated dentinsurface appeared to be collagen-free, and cracked hydroxyapatitecrystals remained, giving a roughsurface appearance. This rough-ened surface might not needadditional acid etching to achieve agood bond with composite resinfilling systems,21 although otherstudies showed that acid etching,

Figure 7: A laser-treated dentin specimenusing the laser settings for enamel(Group B) after the use of 5% aqueousninhydrin solution

Figure 8: Roughened dentin surface after laser irradiation withthe settings for treating enamel (Group B, 500X magnification)demonstrating the absence of a smear layer

Figure 10: Appearance of laser-irradiated and etched dentin(Group C, 500X magnification) demonstrating a smooth andsmear layer-free surface

Figure 9: A dentin specimen of whichhalf of the surface was treated with thesettings for dentin (Group C) and thenthe whole surface was etched with 37%phosphoric acid (Group C) after the useof 5% aqueous ninhydrin solution

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following erbium laser irradiation,should not be omitted.14, 22-23

On the laser-irradiated andetched area there were two obser-vations of particular interest. First,the color was identical to the colorof the etched-only surface.Obviously, the laser-irradiatedsurface was affected by acidetching. The acid removed the free-amino and carboxyl group zoneand the cracked hydroxyapatitecrystal structures, exposing thecollagen underneath toward thesurface. The second finding agreeswith this hypothesis because undermagnification the laser-irradiatedand etched surfaces appearedsmoother when compared to thelaser treatment-only surface,meaning that the acid demineral-ized the hydroxyapatite crystalsthat roughened the surface. Thequestion is whether or not thismicromechanical roughnessfollowing laser treatment is stableand stiff enough for better adhe-sion. Additional studies are neededto answer these questions.

Since there was no difference onthe opposite sides of treated andcontrol areas, it was assumed thatboth energy levels (88 and 150J/cm2) were safe for the pulp tissuewhen there is a 2 mm dentinal wallthickness. These findings are inaccordance with the findings ofother researchers.24

CO N C LU S I O NThe Er.Cr:YSGG laser, when usedon dental hard tissues, may be slowon enamel, but works well ondentin. This study demonstratedthat the remaining treated dentinsurface is microroughened, smearlayer-free, and free of -amino andcarboxyl groups, indicatingcomplete removal of collagen.

Cl

laser in dentistry

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