Evidence-Based

1hDatmentHIGHLIGHTS FROM THE 1996 WORLDWORKSHOP IN PERIODONTICS

State-of-the-art periodontal

therapy involves a wide range

of diagnostic and treatment

options. The 1996 World

Workshop in Periodontics

used an evidence-based ap-

proach to assess the efficacy

of many of these options. This

article describes the evi-

dence-based approach and

summarizes the findings of

the workshop in the areas of

diagnosis and nonsurgical and

surgical periodontal therapy

as well as dental implants.

MARJORIE K. JEFFCOAT, D.M.D.;MICHAEL MCGUIRE, D.D.S.;MICHAEL 0. NEWMAN, D.D.S.

ow does a clinician decide if a particu-lar treatment or diagnostic test is efficacious? Since 1966, the AmericanAcademy of Periodontology has con-ducted conferences on the state of the

art in clinical periodontics. World Workshops in ClinicaPeriodontics have been held in 1966, 1977, 1989 and1996. The purpose of this article is to summarize for thclinician some of the salient findings of the 1996 WorldWorkshop in Periodontics.

EVIDENCE-BASED APPROACH

The 1996 world workshop was unique in that it adopted an evi-dence-based approach to the difficult problem of deciding when paticular treatments or diagnostic methods work. In clinical practicea clinician must weigh a myriad of evidence every day. That evi-dence ranges from personal experience and case reports to con-trolled clinical trials. Traditionally, most clinical decisions in den-tistry have been based on the experience of the clinician. If atreatment seems to work, it is administered again; if the results a]disappointing, the procedure may be abandoned. Therapies testedin this fashion are often unpredictable because the clinician maynot know which factors are important for success and which factorcontribute to failure.

The evidence-based approach strives to strengthen clinical experience through the systematic evaluation of available information,which allows the clinician and patient to benefit from the amasseddata. In an evidence-based approach, all evidence is not given thesame weight.' The stronger the evidence, the stronger the recom-

11

Le

tr-

re

rs

JADA, Vol. 128, June 1997 713

COVER STORY-

TABLE I

S IX Ir 7.

--. - E- IAPPLICATION STRENGTHS WEAKNESSES

mIiainteLnanLe 611r-apy;,fuill periodontal exami:tion is needed for thispurpose

Probing pocket A1 patients Shallow probing depths Moderate-to-deep pocketsdepths associated wi;1th a lack of in a single probing depth

fuiture disease progres- examnination will not dis-sion tinguish with certainty

which teeth will urndergoprogressi've periodontaldestruiction

mation assess-tionis associated with aLack wall not di tingui wthmTent of fuitue disease progres- certainty w teth will

sion; in treated patients, underg progressiVebleeding on probing is periodontal destuctionassociated with an in-creased risk of progres-si,ve loss of attachment

Radiographic At-risk patients Absence of bone loss is Presence ofbone loss on aevidence of bonae as determinaed associated with a lower single radiograph will notloss by PSR screen- risk of fiuture disease distinguish with certainty

ing or periodon- progression which teeth will undergotal examination progressive periodontal

destr-uction

Microbial pau High-risk ingival Rouie ig fferstes3ts refractory pa- plq is associd with limie enefit adult

tients a l~ac:k of dilsease progres- periodontitis

In compromised or re-fractory patients, may beuisefuil in determining thepresence of pathogens

Biochemical pro- Not yet deter- A number of biochemical At present, there are nofiles in gingival mined markers may identify in- specific biochemical pro-cre-vicular fluid dividuals at risk files that characterize

specific periodontal dis-eases3

mendation it will support.While all clinicians form

opinions, an evidence-based ap-

proach puts the most weight on

reports that have clearly de-fined goals, that objectivelymeasure both risks and benefitsof a treatment, that acknowl-edge potential sources of bias inthe study design, and that use

analytic methods to determineboth statistical and clinical sig-nificance. Evidence is ranked inthe following manner.

The double-blind, placebo-controlled clinical trial is gener-

ally regarded as being at thetop of the hierarchy of evidence.This type of trial randomly as-

signs patients to various treat-ments or placebo, and neitherthe patient nor the investigatorknows who received which ther-apy, thereby reducing potentialbias. Of course, not all clinicalquestions are amenable to thisstudy design because of ethicalconsiderations or the fact that

patients may be aware of thetype of treatment rendered(such as in a study comparingroot planing with surgical treat-ment). This type of trial is oftenreferred to as a randomized con-

trolled trial.Other types of studies follow

patients in a randomized proto-col that compares treatmentwith no treatment. It is impor-tant to remember that no treat-ment is not the same as placebotreatment. Because the patient

714 JADA, Vol. 128, June 1997

TEST

COVER STORY

DiS -tS f7E L-D - D .Q7C X 7 F7 t 7 * , _. s.s 's !0:: s d: D CtES s s :#:2 it5 a; w ___s_cBx_ r7-;D _7g* SED v_ r=__-f_ _E: =,,._ _ __-:: 7 As B :Z: : .:s.1: s s.}:7X s:B. . - PE s ,^.s-: :; - _ _,,,, , . = . ,, _ -F- ::: E: : E 7 7 E F

7y

E:y

Cross-sectional andlongitudinal studies

is well aware that no treatmenthas been rendered, this knowl-edge may affect patient-admin-istered home care, such asbrushing and flossing, therebyinfluencing plaque control andcompliance. Furthermore, if theclinician is aware of whichtreatment has been adminis-tered, his or her objectivity inevaluating the results may bereduced.

Longitudinal studies, whichfollow groups of patients or

large cohorts in epidemiologicstudies, can provide importantinformation about the long-termeffects of treatment or the natu-ral history of a disease. If suchstudies are conducted withoutsuitable controls, however, po-tential bias in evaluating theresults may occur.

Cross-sectional studies com-pare groups of subjects-for ex-ample, patients treated withdifferent modes of therapy-ata single point in time. Whilesuch studies are relativelyquick and simple to conduct,they do not give the clinician in-formation regard-ing the effect oftreatment overtime.

Case reportsprovide early in-formation aboutnew clinical tech-niques, often withdetailed methods.Case reports arenot designed toprovide an unbi-ased estimate oftreatment efflca-cy.

Animal andlaboratory studiesprovide importantinformation thatcan be used to im-prove the designof human clinical trials.As clinicians, we must be

able to recognize the differentlevels of evidence because theyallow us to assess the value ofthe information provided. Theevidence-based approach helpsto ensure that efficacious treat-ments are used in practice.This approach does not ignorethe patient and concentratesolely on numbers and statis-tics. To the contrary, the evi-dence-based approach recog-

nizes the importance of patientpreference and quality-of-lifeissues.

IDENTIFYING THEEVIDENCE

efore the meeting, re-viewers who were inter-nationally known experts

in the field were given thedaunting task of summarizingthe literature in the field of pe-riodontitis, with emphasis onmaterial published since thelast world workshop in 1989.Each paper received an exhaus-tive peer review. One common

aspect of eachreview was theuse of evidencetables that pre-sented the im-portant findingsof pertinent lit-erature. A typi-cal evidencetable included,in addition toauthors' namesand summaryresults,strengths andweaknesses ofthe study andthe type of evi-dence provided(from random-ized, double-blind, controlled

clinical trials to case reports).Extensive bibliographies werealso included.

Topics addressed includedsurgical and nonsurgical thera-py, implant therapy, diagnosisand epidemiology of periodontaldiseases. The workshop also ad-dressed medically compromisedpatients, older adults, mucocu-taneous disorders, anxiety andthe pathogenesis of periodontaldiseases. Consensus on eachtopic was reached in group

JADA, Vol. 128, June 1997 715

igEiy:yi.t DEiC~sE:: a :r s: i: F 7:i T:: C: : : :.: rs:rs . z : :z f : : l: ? :: : h EsU: . :. s. 4

COVER STORY

TABLE 2

TR_E MEN T TREATMENT STRENGTHS WEAKNESSESII CAkTEGORY

Ultrasonic and sonicscaling and rootplaning

Res-ults are similarto those for man-ualscaling and rootplaning

Chemnicalplaque Chiorhexidini,e tri- | Significantreduction No cear evie&ncecontrol with mouth- closan with copoly- in gingival inflam- that there is a sxub-rinses and tooth- mer or triclosa:n wIth mation stantial long-termpastes zinc citrate; essential benefit in periodon-

oils; staninous fluor- titis except to controlide coexisting inflamma-

tion

junct to brushi benit priodon-titis

p Sustained-release InAtrapocket resorb- WVhen used as an ad- A few reported sideantimicrobials able or nonresorb- junct to scaling and effects include tran-

able delivery systems root planing, gainsi in sient discomfort,containing a tetracy- clinical attachmenrt erythema, recession,cline antibiotic level and decreases allergy and, rarely,

ini probing depth anid Candidableeding

;:c¢4lindaycn ad strictive periodon- for most a t pa-combintions such as titis tients with periodon-metronidazole and titisamoxicillin

meetings, and all participantsin the world workshop had theopportunity to review and cri-tique the consensus reports be-fore they were finalized.

Each working group wascharged with answering specif-ic, pertinent questions based onthe published evidence. Alltypes of published evidencewere considered, but wereweighed in accordance with thedescriptions above. The consen-sus findings in the areas of di-agnosis, nonsurgical therapyand surgical therapy are sum-marized in Tables 1 through 3.This workshop and its pub-lished proceedings represent

the most comprehensive consen-sus review to date on clinicalperiodontics.2

DIAGNOSINGPERIODONTAL DISEASES

T he world workshop con-sidered both routine clini-cal diagnostic methods,

such as clinical examinationand radiographs, as well asmethods of detecting bacterialpathogens or assessing bio-chemical markers in the gingi-val crevicular fluid. Some of themajor findings are summarizedbelow.

Periodontal screeningand recording examination.

The PSR provides the dentistwith a cost-effective and simplemethod of screening patients forperiodontal diseases.3 Becausethe PSR does not provide atooth-by-tooth assessment ofprobing depth, a full periodon-tal examination is needed for acomplete diagnosis of patientsfound to be at high risk, basedon the screening examination.The PSR usually takes 2 to 3minutes to perform and simplyrequires that the examinerrecord the worst score in asextant.

The workshop clearlyreached consensus that all pa-tients in every practice should

716 JADA, Vol. 128, June 1997

VW %_.__XSW-Pr_ * NW.9 5 V.-W 5 N-uw--Nv%m a ",W

COVER STORY

ILongitudinal, cohort andrandomized clinical trials

Randomiied, dobleblinclinical trials

tudinal-',s,B.sinent ?of.pa..

tients' conitons

be screened for periodontal dis-ease.4 A complete description ofthe PSR is provided in thePeriodontal Screening andRecording System trainingmanual (1992) sponsored by theAmerican Academy ofPeriodontology and theAmerican Dental Association.

Probing depths. These arean integral part of the PSR ex-amination as well as any com-plete periodontal examination.Longitudinal studies haveshown that shallow probingdepths are associated with lackof disease progression. It is in-teresting to note, however, thatthe mere presence of a pocket

does not herald progressive pe-riodontitis in that site. Whileteeth with moderate-to-deepprobing depths are at higherrisk of additional destruction, asingle examination cannot de-termine with certainty whichspecific teeth will undergo de-struction.3'4 Because of this limi-tation, longitudinal record keep-ing and frequent reevaluationsare essential in monitoring dis-ease progression.

Bleeding on probing andindexes. The clinician may as-sess gingival inflammationusing a variety ofmethods, includ-ing bleeding onprobing and in-dexes, such as thegingival index, tograde redness andbleeding. In adultperiodontitis, theabsence of inflam-mation is associ-ated with a lack ofdisease progres-sion; however, thepresence of in-flammation doesnot ensure that agiven tooth will undergo furtherdestruction. Longitudinal stud-ies of treated patients in main-tenance programs show thatgingival bleeding, especially atseveral sequential recall visits,was associated with an in-creased risk of progressive lossof attachment. Therefore, it isessential to monitor patientsfrequently at recall visits.3'4

Radiographs are obtained forpatients at risk of periodontitis,as determined by the PSR or pe-riodontal examination. Boneloss at a single examinationrepresents the amount of bonesurrounding a tooth at a giventime and reflects both the heal-ing and disease that have oc-

curred over a patient's lifetime.As was the case with probingdepth, the mere presence ofbone loss on a radiograph doesnot translate on a tooth-by-tooth basis to further osseousdestruction, but it does increasethe patient's risk of future boneloss.3'4

Bacterial testing. Many re-ports have focused on the poten-tial of bacterial testing to iden-tify patients at risk ofdeveloping connective-tissueand osseous destruction. Thelack of gross plaque deposits is

associated witha lack of diseaseprogression (aclean mouth is ahealthy mouth).However, a mul-titude of cross-sectional andlongitudinalstudies did not,for the mostpart, demon-strate a benefitfrom bacterialtesting in com-mon forms ofadult periodon-

titis. This was true regardlessof the method used to detect thebacteria (that is, culture, DNAprobes or immunoassays).

Therefore, the world work-shop consensus report did notrecommend routine bacterialtesting for adult periodontitis atthis time. It is important to rec-ognize that this finding is basedon the 1996 evidence. As testsand our knowledge of the patho-genesis of periodontitis im-prove, the benefit ofnew testswill continue to evolve.Bacterial tests may eventuallybe routinely beneficial to pa-tients and practitioners.34

Case reports, however, havepointed to the usefulness of bac-

JADA, Vol. 128, June 1997 717

C~KOVER STORY

Regenerative procedures to fa-cilitate growth of new perio-dontal ligament, cernentum andbone over previously diseasedroot surfaces

Extraoral aultogenous bonegrafts

probing depth with osseous re-contouring; apically reposBi-tioned flap with or withoutbony recontouring used incrown-lengthening proceduresto pro-vide biologic width

High potential for bone growth

Intraoral autogenous grafts Case reports indicate bone gain(such as maxillary tuberosity, ofmore than 50%; controlledhealing extraction sites, os- studies comparing grafts withseous coagulum) nongrafted bone show improved

clinical attachment levels andbone, but not aBs great as thosein case reports

Allografts-tissue transferred Bone fill has been reported in afrom one person to another; high proportion of defects involv-freeze-dried bone allograft ing freeze-dried bone allograft

Alloplasts-synthetic grafts_ absorbable: plaster, calciuimcarbonates, ceramics such astricalcium phosphate and ab-sorbable hydroxyapatite (HA)_ nonabsorbable: dense I-IA,porouis HA, bioglass- calcium-coated polymer poly-methylmethacrylate and hy-droxymethylmethacrylate

Improved probinag depth andattachment level

Some evidence of histologic re-generation in calcium-coatedpolymer polymethylmethacry-late and hydroxymethyl-methacrylate

most ravorable rests are inClass II furcations in themandible and infrabony defects;no need for second-stagesurgery (resorbable only)

Gingival augmetation to Pedicle gsrafts Improve esthetics/cosmetic re-promote root coverage Free soft-tiassue grafts (epithe- sults; decrease root sensitivity;

lialized or connective-tissue manage defects resulting fromgraft) root caries removal or cervical

abrasion; manage mucogingivalCombination grafts defects- connective tissue or biode-gradable membrane barrierplus pedicle graft- coronally positioned, preyi-ously placed soft-tissue graft- nonbiodegradable membranebarrier plus pedicle graft

Endosseosdetl i ats Two-tgad sag - Dea n t eplants; titaniu; tit mrep ents f i t

alloy; hydroyaptiteco'ated in fully andi parilyedn-implants lous patients

718 JADA, Vol. 128, June 1997

pe iL-regel

COVER STORY

Second surgical site (such as .Limited case report datailiac crest); rootrsorptionmaybe associatedwih fkresh graft4

Case reports; comparativecontroHed clinical studies

Osteogenic potential may vary Field test; controlledfrom rial to rvial; patient differ- clinical trialsences; clinician variability

Histologic findings indicate Controlled clinical trialsthat syynthetic grafts primarilyact as fillers, with little if anyregeneration

move the membrane

Clinical results similar to thoisefor nonaresorbable membranesb-ut less e-vidence available toallow a comparison of pre-dictability with respect tononresorbable mnembranes

CaAse reports; coapaiso

rlown caes: smcoing,oluetreat-

temnic disease., hisitory of radia-tion therapy, active skeletalgrowrth

terial and antibiotic sensitivitytesting in special patient popu-lations. These populationswould include, but not be limit-ed to, patients who are refracto-ry to other periodontal treat-ment, patients with rapidlyprogressive periodontitis orearly-onset periodontitis andcertain medically compromisedpatients.34

The recent literature con-tains many cross-sectional andlongitudinal studies of biochem-ical markers in gingival crevicu-lar fluid. Crevicular fluid maybe easily collected by inserting afilter paper strip into a pocket.The crevicular fluid is analyzedfor biochemical markers associ-ated with inflammation, tissueinjury or tissue death. Whilethese studies may offer promisefor identifying individual pa-tients at risk, there are no spe-cific biochemical profiles that,based on the evidence availablein 1996, characterize specificperiodontal diseases or indicatea treatment recommendationbased on the results of thetests.34

Consensus: diagnosis.Although advances are beingmade in many areas, currentevidence shows that clinicalsigns of inflammation, clinicalattachment level, probing depthand radiographic imaging re-main the principal tools formaking decisions regarding di-agnosis and treatment of perio-dontitis.

NONSURGICALPERIODONTAL THERAPY

Nonsurgical periodontal therapyincludes both mechanical andchemotherapeutic methods ofcontrolling plaque and reducinginflammation. The benefits ofmechanical instrumentation(that is, scaling and root plan-

JADA, Vol. 128, June 1997 719

COVER STORY

ing) have been demonstrated ina myriad of longitudinal, cohortand randomized clinical trials.Demonstrated benefits of scal-ing and root planing include de-creased gingival inflammation,decreased probing depth andmaintenance of clinical attach-ment level. The evidence indi-cates that similarresults may be ob-tained with ultra-sonic and sonic in-struments andmanual instru-ments. Regardlessof the methodsused, meticulousattention to detailis required toachieve optimalresults.56Chemical

plaque controland gingival in-flammation.Chemical plaquecontrol has be-come an impor-tant part of theclinician's arma-mentarium.Significant reduc-tions in gingivalinflammationhave been demon-strated for chlorhexidine; tri-closan with copolymer or tri-closan with zinc citrate;essential oils; and stannous flu-oride. The magnitude of gingi-val inflammation reduction wasgreatest for chlorhexidine.6-9 Theevidence supporting these re-sults comes from multiple, ran-domized, double-blind, con-trolled clinical trials. Theevidence available in 1996 wasalso clear on another point:these antiplaque and/or antigin-givitis agents do not offer a sub-stantial benefit for the treat-ment of periodontitis.69 They

may, however, contribute to thecontrol of gingival inflammationthat exists with periodontitis.

Supragingival irrigation maybe used as an adjunct to tooth-brushing and has been shown toaid in the reduction of gingivalinflammation. Even when sub-gingival irrigation is used, how-

ever, the evi-dence showsthat there areno clear sub-stantiallong-term bene-fits for thetreatment of pe-riodontitis.69

Antibiotictherapy andperiodontics.Researchershave extensivelystudied the sys-temic adminis-tration of antibi-otics includingtetracyclines,metronidazole,spiramycin,clindamycin andothers.8 Therisk-benefitratio indicatesthat systemicantibiotics

should not be used for the treat-ment of gingivitis.6 When adultperiodontitis is considered, theevidence is based on random-ized, double-blind, controlledclinical trials. While the conclu-sions of individual trials maydiffer, the preponderance of ev-idence from well-controlled,randomized, blinded clinicaltrials indicates that systemicantibiotics do not offer suffi-cient benefit to overcome riskssuch as drug sensitivity andemergence of antibiotic-resis-tant pathogens for the routinetreatment of common forms of

adult periodontitis.6'8However, the situation differs

for aggressive forms of periodon-titis, such as rapidly progressiveor refractory periodontitis. Onlya small proportion of patients(estimated to be less than 10percent of people with periodon-tal disease) are affected bythese forms of periodontitis.Randomized, double-blind, clini-cal trials, as well as longitudi-nal assessments of patients, in-dicate that systemic antibioticsmay be useful in slowing dis-

681ease progression.'Local delivery of antimi-

crobial agents. In recentyears, there has been consider-able interest in the applicationof antimicrobial agents directlyin the pocket, thereby eliminat-ing or reducing many of the ad-verse side effects associatedwith systemic antibiotics. Inrandomized, double-blind, con-trolled, clinical trials, re-searchers have studied both re-sorbable and nonresorbableintrapocket delivery systemscontaining antimicrobials.68When these systems were usedas an adjunct to scaling and rootplaning, modest gains in clinicalattachment level and decreasesin probing depth and gingivalbleeding were demonstrated. Afew side effects were reported,including transient discomfort,erythema, recession, allergyand, rarely, Candida infection.

Consensus: nonsurgicalperiodontal therapy. Basedon the evidence discussedabove, incorporation of systemicantibiotic therapy into the rou-tine management of most casesof adult periodontitis is not jus-tified at this time. Chemicalplaque control agents, appliedtopically or by irrigation, maybe useful in controlling gingivalinflammation, but are not of

720 JADA, Vol. 128, June 1997

COVER STORY

substantial benefit in the treat-ment of periodontitis. Locallydelivered antimicrobial agentsmay be useful on a short-termbasis when combined with me-chanical therapy. Scaling androot planing accompanied byoral hygiene procedures re-mains the first mode of treat-ment for adult periodontitis.After adequate time has passedto evaluate the healing re-sponse, clinicians must re-eval-uate patients' conditions to de-termine if further mechanical,adjunctive, pharmacologicaland/or surgical treatment is in-dicated.

SURGICAL PERIODONTALTHERAPY

Surgical pocket therapy. Thearmamentarium of surgical pe-riodontal therapy is composedof techniques to provide accessto root surfaces and bone de-fects for debridement and rootplaning, facilitate regeneration,augment the gingiva, promoteroot coverage and place dentalimplants. Traditional pockettherapy provides access to rootsurfaces and bony defects fordebridement by the clinician.The overall goal is to makeplaque control easier for the pa-tient to perform and to enhancerestorative cosmetic dentistry.10Many surgical techniques areavailable, including gingivecto-my, the apically positioned flap(with or without osseous contour-ing) and the modified Widmanflap (or access-type flap).

Extensive randomized clini-cal trials and longitudinal stud-ies have demonstrated the effi-cacy of these procedures.'0 Allprocedures decrease pocketdepth and, with the exception ofgingivectomy, increase clinicalattachment level. The evidencefrom long-term studies that fol-

lowed up patients for 5 yearsafter surgery indicates that thegreatest reduction in probingdepth was achieved when anapically repositioned flap wascombined with osseous recon-touring.'0

The clinician should note,however, that procedures de-signed to reduce probing depthmay increase recession, withconcomitant root sensitivity andpossible compromise of esthet-ics. Thus, selection of a particu-lar surgical procedure must al-ways be based on the particularneeds of the patient.'0"'1Regardless of the approach se-lected, maintenance (includingregular recall visits, periodontalprophylaxis and oral hygieneinstruction) is important tolong-term success.

Periodontal regeneration.Periodontal regeneration proce-dures are de-signed to facilitategrowth ofnew pe-riodontal liga-ment, cementumand alveolar boneover previouslydiseased root sur-faces. The worldworkshop consid-ered a wide vari-ety of regenera-tive techniques,including bonegrafts and guidedtissue regenera-tion.

Bone grafts.Bone graftingtechniques involvethe use of naturalbone or syntheticbone materials.12 Natural bonegrafts consist of autografts(bone transferred from one posi-tion in the body to another posi-tion in the same patient), allo-grafts (tissue transferred from

one person to another) andxenografts (tissue transferredfrom one species to another).Limited case report evidenceshows that extraoral autoge-nous bone, such as hip grafts,offer high potential for bonegrowth.'2 Extraoral sites are as-sociated with the need for a sec-ond surgical site and, in somecases, fresh grafts may be asso-ciated with root resorption.

Intraoral autogenous graftseliminate the need for extraoralsurgical sites. Sources of intra-oral autogenous graft bone in-clude, but are not limited to, themaxillary tuberosity, healingextraction sites and osseous co-agulum. Evidence from case re-ports indicates that bone fill ex-ceeding 50 percent of theosseous defect may be achieved.Interestingly, controlled studiescomparing grafted with non-

grafted sitesalso show signif-icant improve-ments in clinicalattachment lev-els and bonegain, but themagnitude ofgain is less thanthat exhibitedin the case re-ports.'2"13

Freeze-drieddemineralizedbone is one ofthe most fre-quently usedand well-studiedbone-graft ma-terials in perio-dontics. Freeze-dried demineral-

ized bone is an allograft materi-al, meaning that it is harvestedfrom one person, prepared anddemineralized before beinggrafted to another person. Thedemineralization step is impor-

JADA, Vol. 128, June 1997 721

COVER SIORY

tant for the activity of morpho-genetic proteins, which appearto be responsible for the bone-forming, or osteoinductive,qualities of the graft material.

Case reports and controlledclinical trials have demonstrat-ed the bone-form-ing potential ofthis graft materi-al. Bony fill hasbeen reported tooccur in a highproportion ofsites."2 However,the evidence doesindicate some vari-ability in the pre-dictability andamount of bone fillachieved. Thismay occur becausethe osteogenic po-tential of thedonor bone mayvary, resulting indifferent os-teogenic potentialfrom different vials of graft ma-terial. Variability may also re-sult from patient and cliniciandifferences.

Since allografts are trans-ferred from one person to anoth-er, the tissue bank should en-sure proper handling andtesting to minimize the possibil-ity of transferring viruses orother pathogens to the pa-tient.'2'3 Such procedures shouldinclude polymerase chain reac-tion testing for HIV. As of 1996,there were no reports ofHIVtransmittal in freeze-dried de-mineralized bone.

Table 3 lists a wide variety ofsynthetic graft materials usedin alloplasts. These grafts maybe absorbed by the patient overtime or not be absorbed.Controlled clinical trials havedemonstrated improvements inprobing depth and attachment

level with the use of syntheticgrafts.'2"3 Histologic findings,however, indicate that in gener-al, synthetic grafts act primari-ly as space fillers, with little ifany regeneration. However,some histologic evidence of re-

generation hasbeen demon-strated with thesynthetic mate-rial composed ofcalcium-coatedpolymer, poly-methyl-methacrylateand hydroxy-methyl-methacrylate.12"13

Guided tis-sue regenera-tion. Guidedtissue regener-ation proce-dures use phys-ical barriers or

membranes tofacilitate selec-

tive population of the root sur-face by cells capable of formingnew tissue. During the healingperiod after periodontalsurgery, the cells of both theperiodontal ligament and thepocket epithelium migratealong the root surface. If theepithelial cells migrate apicallyalong the root surface, healingmay occur with either a longjunctional epithelium or aresidual periodontal pocketwithout significant regenera-tion of connective tissue orbone. The goal of the mem-brane is to exclude the epithe-lial cells from the root surfacewhile maintaining a space intowhich the periodontal ligamentcells can grow. The ideal resultis regeneration.

Investigators have studiedboth resorbable and nonre-sorbable membranes. Re-

sorbable membranes do not re-quire a second surgical pro-cedure to remove the membraneapproximately 6 weeks after theprocedure. The sources of evi-dence demonstrating the effica-cy of guided tissue regenerationrange from randomized, con-trolled clinical trials to case re-ports.13 While less evidence isavailable for resorbable mem-branes than for nonresorbablemembranes, significant im-provements in clinical attach-ment levels have been shownfor both types of membranescompared with debridementalone. Most favorable resultsare reported for Class II furca-tions in the mandible and forintrabony defects. Less favor-able results have been reportedin maxillary molar and ClassIII (through and through) furca-tion defects.12"13

Mucogingival procedures in-clude procedures to enhancekeratinized tissue, cover ex-posed roots and eliminatefrenum pulls. In recent years, awide variety of surgical proce-dures have been developed anddescribed in case reports andcomparison studies.'4 Some ofthese surgical techniques arelisted in Table 3. In general,these techniques managemucogingival defects, potential-ly cover root surfaces, decreaseattendant root sensitivity andimprove the esthetic results.'4"5

Dental implants. Not all pe-riodontal therapy involves thetreatment of teeth. The replace-ment of teeth with dental im-plants and the long-term main-tenance of dental implants arealso an important part of clini-cal periodontics today. Manylongitudinal studies have clear-ly demonstrated the predictabil-ity of endosseous dental im-plants in fully and partially

722 JADA, Vol. 128, June 1997

COVER STORY

edentulous patients.16'17 Manyimplant designs and surfaceshave resulted in high successrates (often exceeding 95 per-cent in good-quality bone).

While most evidence is avail-able for titanium implants,some evidence exists to supportthe use of hydroxyapatite andtitanium plasma-sprayed im-plant surfaces. There is also evi-dence to support the use of bothtwo-stage systems, which re-quire a second surgery to ex-pose the implant, and one-stageimplant systems.17-'9 Few stud-ies in the literature addressspecific risk factors. Cliniciansshould exercise caution whentreating patients who smokeand those with untreated perio-dontal diseases, poor oral hy-giene, uncontrolled systemicdisease, a history of radiationtherapy in the region or activeskeletal growth.

Consensus: surgical perio-dontal therapy. The evidenceis clear that surgical pockettherapy results in the reductionofmean presurgical probingdepths for periods exceeding 5years. Evidence also demon-strates that regeneration can beachieved in intrabony defectsand mandibular Class II furca-tions. Many studies havedemonstrated dramatic im-provements in the ability tocover exposed roots with soft-tissue grafts as well as the pre-dictability of endosseous dentalimplants in fully and partiallyedentulous patients.

HOW IS INNOVATIONTRANSLATED TOCLINICAL PRACTICE?

Pzeriodontics is a rapidlychanging field, with con-stant innovation improv-

ing our ability to diagnose, pre-vent disease and slow its

progression, and regenerate lostperiodontium. Innovation mayspring from any member of thedental/medical team, and itmay influence the type of evi-dence available to practitionersin judging thevalue of improve-ments in periodon-tal diagnosis andtreatment.Many new sur-

gical techniques,or new uses for ex-isting drugs, arefirst proposed andused by clinicaldentists. Not sur-prisingly, the ear-liest descriptionsof these methodsare often in the form of case re-ports. These case reports areusually not intended to providea thorough statistical analysisof efficacy, but they often de-scribe a case with clear benefits.Good results are often revisitedin controlled clinical trials.Notably, the degree of benefitderived from the new treatmentis often greater in single casereports than in large cohorts ofpatients entered into a trial.Nonetheless, the body of evi-dence clearly demonstrates aclinical benefit for the manysurgical and nonsurgical proce-dures used to treat periodontaldiseases today.

Another source of innovationare the basic scientists who de-velop new drugs and devices forthe diagnosis and treatment ofperiodontal diseases. Thesedrugs include both prescriptionand dentist-delivered drugs,such as chlorhexidinemouthrinse or tetracycline-im-pregnated fibers, and over-the-counter preparations such astoothpastes and mouthrinses.Each new drug must pass strict

guidelines in accordance withthe U.S. Food and DrugAdministration. In general, twowell-controlled clinical trialsare needed to be reviewed bythe FDA. Therefore, evidence

for new drugtherapy isbased on a highproportion ofdouble-blind,randomized,placebo-con-trolled clinicaltrials.

The evi-dence-based ap-proach offers abridge from sci-ence to clinicalpractice. The

clinician must integrate the ev-idence with patient prefer-ences, scientific knowledge,clinical judgment and personalexperience. The evidence-basedapproach empowers the clini-cian by facilitating informeddecision-making based on fact,not opinion. Most important, itallows us to care for our pa-tients.

CONCLUSION

The evidence presented at the1996 World Workshop inPeriodontics demonstrated theefficacy of many diagnostic andtreatment modalities. However,innovation does not stop withthe world workshop. Our pro-fession is constantly striving toimprove patient care, throughthe use of creative but soundscientific principles.Ultimately, we all benefit. .

The 1996 World Workshop in Periodontics,held July 13-17, 1996, in Landsdowne, Va.,was sponsored by the American Academy ofPeriodontology. The AAP thanks Procter &Gamble for its generous donation in supportof the World Workshop. Individuals whomade the World Workshop possible are toonumerous to detail, but the authors wish tospecifically acknowledge the organizing com-

JADA, Vol. 128, June 1997 723

-COVER SIORY

K~~~~~~~.Dr. Jeffooat ls the Dr McGuire Is In pri-Roaen Profeasor and vate practice llmitedchair, Department of to periodontica,Periodontics, Uni- Houston; a clinicalversity of Alabama assitnt prfeosorSchool of Dentlar, of periodontica,1919 7th Ave South, Univeralty of TexasBirmingham, Ala Dental Branch at

35294-0007; and Houston; a clinicalchair, Diagnosls assiatant professorSoction, 1996 World of perodontics,Workshop In Perlo- Univesity of Texasdonticas Address Health Scioncereprint requests to Center at SanDr. Jeffcoat. Antonio; and secro-

tary of the American

mittee, including Drs. Academy ofMichael G. Newman, Poriodontology.chair; Leonard S.Tibbetts, vice chair; Donald F. Adams; JackG. Caton; Sebastian G. Ciancio; Robert T.

U. Ferris; Robert J.Genco; Jan Lindhe;James T. Mellonig;Ronald Nevins; S.Timothy Rose;Mariano Sanz; andRobert Schoor.

1. Newman MG.Dr. Newman is an ad- Improved clinical deci-

ltunct professor, sion making using theUniverst of Calfo- evidence-based ap-nia at Los Angeles proach. AnnSchool of Dentity, Periodontol 1996;1:i-ix.section of Perkdn- 2. 1996 Worldtics; o e Workshop inMediCal Sci5Um5 Periodontics. Annsystems kw-., Plow Periodontol 1996;1:1-port Beach, Cell.; 946.and chir, 1996 World 3. Armitage GC.Woricaliop Organizing Periodontal diseases:

diagnosis. AnnCommittee. Periodontol 1996;1:37-215.

4. Consensus report on periodontal diseases:epidemiology and diagnosis. Ann Periodontol1996;1:216-22.

5. Cobb CM. Non-surgical pocket therapy: me-chanical. Ann Periodontol 1996;1:443-90.

6. Consensus report on non-surgical pockettherapy: mechanical, pharmacotherapeutics,

and dental occlusion. Ann Periodontol1996;1:581-8.

7. Hancock EB. Prevention. Ann Periodontol1996;1:22349.

8. Drisko CH. Non-surgical pocket therapy:pharmacotherapeutics. Ann Periodontol1996;1:491-566.

9. Consensus report on prevention. AnnPeriodontol 1996;1:250-5.

10. Palcanis KG. Surgical pocket therapy.Ann Periodontol 1996;1:589-617.

11. Consensus report on surgical pocket thera-py. Ann Periodontol 1996;1:618-20.

12. Garrett S. Periodontal regenerationaround natural teeth. Ann Periodontol1996;1:621-66.

13. Consensus report on periodontal regenera-tion around natural teeth. Ann Periodontol1996;1:667-70.

14. Wennstrom JL. Mucogingival therapy.Ann Periodontol 1996;1:671-701.

15. Consensus report on mucogingival thera-py. Ann Periodontol 1996;1:702-6.

16. Cochran D. Implant therapy I. AnnPeriodontol 1996;1:707-91.

17. Fritz ME. Implant therapy II. AnnPeriodontol 1996;1:796-815.

18. Consensus report on implant therapy I.Ann Periodontol 1996;1:792-5.

19. Consensus report on implant therapy II.Ann Periodontol 1996;1:816-20.

724 JADA, Vol. 128, June 1997