Does oral health promotionimprove oral hygiene andgingival health?

RICHARD G. WATT & VALERIA C. MARINHO

The dental profession has had a long-standing

interest in the prevention of dental diseases. Histor-

ically, the dominant preventive approach has been

based on a behavioral model (34). This has placed

emphasis on providing oral health information to

patients and the general public with the assumption

that improvements in knowledge will lead to changes

in oral health behaviors and, ultimately, better oral

health status. Dental health education programs were

developed particularly for use in schools and clinical

settings. These programs utilized a range of educa-

tional methods and materials designed to improve

oral health knowledge and awareness (34).

In recent decades, in line with developments in

public health, a shift in emphasis has taken place in

prevention. Largely through the influence of the

World Health Organization, the health promotion

movement has emerged (37). In this approach a wide

range of factors determining health are recognized. It

therefore moves beyond a focus on knowledge and

behaviors, to acknowledgment of the importance

of social, environmental and political determinants

of health. Health promotion encompasses a range of

complementary actions to promote health and well

being. Based upon these principles, oral health pro-

motion has developed as the contemporary approach

to tackling oral diseases. Oral health promotion seeks

to achieve sustainable improvements in oral health

and reduce inequalities through action directed at

the underlying determinants of oral health. An

essential component of this process is multidiscipli-

nary action, which utilizes a range of complementary

strategies (38).

Oral health promotion has focused primarily on

the prevention of periodontal diseases, and to a lesser

extent on dental caries. Although some uncertainty

remains over the natural history of periodontal

disease, it is well established that adequate plaque

control is the most important measure used to pre-

vent this condition (1, 25).

As in clinical dentistry, considerable interest has

been focused on the evidence base for oral health

promotion. In the last 10 years, several reviews have

been undertaken to assess the effectiveness of oral

health promotion interventions (4, 14, 15, 28, 32).

These reviews have stimulated much debate over the

value of oral health promotion and the ways in which

preventive action should be developed in the future

(35).

This paper reviews the quality of the methods and

summarizes the findings of oral health promotion

effectiveness reviews and recent oral health promo-

tion trials in relation to oral hygiene and gingival

health. The specific objectives are:

• To search for and critically assess oral health pro-

motion systematic reviews on the effectiveness of

interventions in reducing plaque and gingival

bleeding.

• To search for and critically assess controlled trials

published subsequent to the oral health promotion

reviews on the effectiveness of interventions in

reducing plaque and gingival bleeding.

• To summarize qualitatively the evidence on the

effectiveness of oral health promotion interven-

tions in relation to plaque control and gingival

bleeding.

Search strategy

To address the study question �Does oral health pro-

motion reduce plaque levels and gingival bleeding?�we searched the following databases in The Cochrane

Library, Issue 1, 2004 for relevant systematic reviews:

35

Periodontology 2000, Vol. 37, 2005, 35–47

Printed in Denmark. All rights reserved

Copyright � Blackwell Munksgaard 2005

PERIODONTOLOGY 2000

the Cochrane Database of Systematic Reviews

(CDSR), the Database of Abstracts of Reviews of

Effects (DARE), the Health Technology Assessment

Database (HTA), and the NHS Economic Evaluation

Database (NHS EED). The Cochrane Central Register

of Controlled Trials (CENTRAL) was also searched for

relevant trials. We searched MEDLINE (through

PubMed) without date limits or language restriction,

in April 2004. The subject search strategy used to

locate both systematic reviews and trials in MEDLINE

was combined with relevant methodological filters:

[(review OR overview OR meta analys* OR ((clinical

or controlled) and trial)) and (hygiene OR plaque OR

gingivitis OR gingival bleeding) and (dental OR oral)

and health and (education OR promotion).]

The same subject search strategy was used to

search The Cochrane Library databases and registers,

but without the filters:

[(hygiene or plaque or gingivitis or (gingival next

bleeding)) and (dental or oral) and health and (edu-

cation or promotion).]

All records electronically identified were scanned

by title, abstract (when available) and ⁄or keywords by

both authors (R.G.W., V.C.M.), and the full-text of all

reports considered potentially relevant was obtained.

The electronic searches were supplemented with

material identified in the reference lists of relevant

articles and in the authors’ personal files.

Study selection, assessment ofstudy quality, and data extraction

Data (for inclusion decisions, study appraisal and

data extraction) were independently collected in

duplicate by both authors and, in case of any disag-

reement, consensus was achieved through discus-

sion.

Inclusion ⁄ selection criteria

We included only reports of systematic reviews and

controlled trials (randomized or quasi randomized)

which specifically stated that they assessed reduc-

tions in dental plaque levels and ⁄or gingival bleeding(gingivitis) and compared health education ⁄healthpromotion interventions not involving clinical pro-

fessional input or the use of pharmacological inter-

ventions, such as antiplaque agents – these included

school or community based programs ⁄ campaigns,

professional instruction, self-instruction manu-

als ⁄ leaflets, home-visits, self assessments, etc. Indi-

vidual studies (trials) where the participants were

from the general population, of all age groups and

settings, were eligible for inclusion. Studies ⁄ trialsinvolving special groups only, such as orthodontic

patients, or involving only medically compromised

groups were excluded. Studies ⁄ trials assessing only

denture plaque were also excluded.

Validity assessment and data extraction

From each systematic review included, we extracted

data on the review focus ⁄primary purpose, type of

research ⁄ study design(s), specific intervention(s),

participants, and relevant outcomes included, sour-

ces used to locate research (with time period covered

and any language restrictions), criteria used to assess

study quality, methods used to assess studies and

extract data, number of studies included, methods

used to combine ⁄ summarize studies and to investi-

gate differences between them, results with respect to

outcome(s) of interest and the review’s conclusion(s).

Specific assessment of study quality was based on

the following data (and coded as �yes, no, unclear�):focused question, appropriate selection criteria,

comprehensive search, validity assessment, data

extraction in duplicate, appropriate data synthesis

(qualitative and ⁄or quantitative).From each controlled trial included, we extracted

data on study details (year study began, place where

study was conducted [country], duration of study),

methodological quality (reporting of allocation,

blinding, attrition), baseline characteristics of par-

ticipants (including number, age [mean ⁄ range], andplaque ⁄ gingivitis severity at start, and setting where

participants were recruited), characteristics of inter-

ventions (including type of intervention, methods to

deliver the intervention ⁄ instructions, frequency and

duration of intervention), outcomes (plaque and

gingivitis indices and scores reported over the follow-

up period) and results. Specific assessment of study

quality was based on the following data (and coded

as �yes, no, unclear�): allocation concealment, blind

outcome assessment, drop-outs listed by study

group.

It should be noted that only the experimental

(intervention) studies published from 1995 onwards,

which are not described in the existing systematic

reviews, and which fall into the criteria for inclusion

described above, have been data extracted and

quality assessed. However, a list of all potentially

relevant trials located by the searches is available on

request.

36

Watt & Marinho

We provide a critical description of each systematic

review (Table 1) and of the trials published recently

and not covered in these reviews (Table 2). In order

to undertake the critical appraisal of each study, we

have used previously published checklists for sys-

tematic reviews and randomized controlled trials,

respectively (9, 21). These checklists follow generally

accepted and widely used criteria to assess the

methodological quality of these types of research.

A qualitative compilation (overview) of findings is

provided. (A quantitative synthesis is not justified,

primarily because we have described in detail only

recently published controlled trials [published from

1995 onwards, which were not considered ⁄ cited in

the existing systematic reviews.]).

Search results and study selection

The combined electronic searches found 443 poten-

tial titles [205 in PubMed, 179 in CENTRAL, 6 in the

DARE, 47 in the CDSR, 6 in the NHS EED]. We

scanned titles, keywords and abstracts (where avail-

able) of publications from 1995 to 2004 for mention

of the outcomes of interest and of oral health pro-

motion interventions or for any suggestion that the

study was relevant to the stated objectives of this

paper. We selected 27 reports as potentially relevant

studies (six reports of systematic reviews and 22 re-

ports of primary studies) to be assessed further.

These included one trial report published in Spanish

and one in Polish. Searching other sources, such as

reference lists, located two additional reports of sys-

tematic reviews published in 1994.

There are six reports relating to five included sys-

tematic reviews (4, 14–16, 28, 32), 13 reports relating

to 13 included trials (2, 3, 6, 8, 12, 17, 19, 20, 22, 24,

26, 36, 39), five reports relating to five excluded

studies – four of which are not randomized or quasi-

randomized controlled trials (5, 23, 7, 29) and one

which is a trial, but on orthodontically treated

patients (18), and four reports relating to four studies

that were not assessed as one was published in Polish

(10) and three in journals which could not be located

(11, 13, 33).

Characteristics of reviews and qualityassessment

A great variety of educational and behavioral inter-

ventions were considered in the reviews, but generally

not clinical interventions and social ⁄ environmental

approaches. Not all the reviews looked for studies

of a specific design to answer their questions.

Although controlled trials were specifically included

in a few reviews, studies of lower levels of evidence

were also included, and some reviews were unclear

about the study designs included. There were no

general restrictions in terms of participants included

(all age ranges, general population and specific

groups).

A detailed assessment of the quality of the iden-

tified reviews highlighted a range of concerns

(Table 1). Particular areas of concern related to how

focused the objectives of the reviews were and the

comprehensiveness of the searches undertaken.

None of the reviews searched for published and

unpublished literature and considered all languages.

Due to a lack of detail presented in the review

methodologies, it was difficult to precisely determine

other parameters of quality such as the appropriate-

ness of the selection criteria and data synthesis.

Other areas of weakness include the screening, data

extraction and quality assessment of primary studies.

Due to the limitations of the reviews, their conclu-

sions should be viewed with a degree of caution.

Kay & Locker (14)

The question and the inclusion criteria are broad. A

reasonable literature search was conducted. However,

only studies published in English were included and

important studies may have been missed. Details of

the review process, such as how many authors were

involved in each stage of the review, were not re-

ported. Appropriate study details were presented and

it is stated that a validity assessment was performed

(but this was not presented). It was therefore difficult

to interpret the reliability of the individual studies.

Given the heterogeneity in the studies in terms of in-

tervention, design, populations and outcomes, the

appropriateness of pooling the results is unclear,

especially as heterogeneity was not formally assessed.

The pooled results should therefore be interpreted

with caution. Overall, the authors’ conclusions appear

to be supported by the results presented.

Kay & Locker (15)

There are no details of study participants or methods

of data extraction. The search strategy was limited to

one database and there is no attempt to identify

unpublished literature, although the authors do ac-

knowledge these points, i.e. that relevant literature

may have been missed. The use of validity scores to

rate study quality is problematic when used to cate-

37

Oral health promotion

Table

1.

Main

featuresandresu

ltsofsystematicreviewspublish

edin

the1990sontheeffects

ofHPinterventionsonplaque⁄gingivitis

Study

Focus

Inclusioncriteria

Search⁄Studyselection⁄

Quality

assessment⁄D

ata

extraction

No.ofstudiesincluded⁄D

ata

synthesis⁄

Investigationofheterogeneity⁄Findings

(forplaquelevels

and⁄orgingivalbleeding)

Kay&

Locker(14)

(andKay&

Locker[16])

Effectiveness

ofhealth

promotionaim

edat

improvingoralhealth.

Studiesreportinganevaluative

componentwere

included.

Detailsofparticipants

not

specified.

Interventions:

toothbrush

ingprograms;

parents’educationon

children’s

dentalhealth;

parentaltoothbrush

ing

instruction;mass

media;

interview

withpsychologist;

computergames,

andclinical

andfluorideinterventions.

Outcomemeasu

res:

oral

hygiene(changesin

plaque

levels).

MEDLIN

E,CIN

AHL,SSCI,reference

listsofarticlesandjournals

were

searchedselectedexp

ertsand

practitioners

were

contacted.

English

languagepapers

from

1979were

selected.It

isnotstated

how

thepapers

were

selected

andassessed,orhow

manyof

theauthors

perform

edthe

studyselection,quality

assessment

anddata

extraction.Method

forassessingvalidity

(�Petit�

criteria)placedparticular

weightonthedefinition,

reliabilityandvalidityofthe

outcomemeasu

res,

andthe

drop-outrate.

Heterogeneityconsideredin

term

sofstudy

design,interventions,

etc.,butnotassessed

form

ally.RCTs(n

=23):most

studies

usedplaquelevels

astheoutcome

measu

re.Themajority

ofstudieswithsh

ort

follow-upsh

owedsignificantim

provements

inplaquelevels,whilst

studieswithlong

follow-upsu

ggestedthatinstructionand

educationaboutplaquecontrolwere

not

effectivein

thelongterm

.Themore

elaborate

interventionsappearedto

beno

more

successfulin

reducingplaquelevels

thanthemore

simple

approaches.

Ameta-analysissh

owedthatthemean

interventioneffectwasa0.316reductionin

thePlaqueIndex(95%

CI[–

0.063,0.695]),

butthis

wasnotstatisticallysignificant.

Quasi-experimentalstudies(n

=33):there

wasnoconvincingevidencethatschool-

basededucationprogramshadanyeffect

ontheplaquelevels,evenwhendaily

brush

ingatschoolwaspart

ofthe

program.School-basedprogramshavenot

beendemonstratedto

affectoralhygiene.

Inclinic-andwork-basedinterventions,

someexp

erimentalplaquecontrol

programswithadultsdemonstrated

dramaticreductionsin

plaquelevels.

Educatingtheparents

aboutplaque

controlin

their

youngchildrenwas

effective.Single-gro

upstudies(n

=22):

these

were

poorstudiesandnoconclusions

could

bedrawn.

38

Watt & Marinho

Kay&

Locker

(15a)

Effectiveness

of

dentalhealth

education

interventions.

Controlledtrials

andstudies

usingso

meform

ofcontrol

groupwere

included.

Detailsofparticipants

notsp

ecified.

Interventions:

programsaim

ed

atplaqueremovaland

gingivalhealth(professional

instruction,self-instruction

manuals,homevisits,

cognitive

therapy,self-assessments).

Outcomemeasu

res:

plaque

levels,gingivalbleedingscores.

MEDLIN

E(1982–94)andreference

listsofretrievedarticleswere

searched.English

language

papers

were

selected.It

isnot

statedhow

thepapers

were

selected,

orhow

manyoftheauthors

perform

edthestudyselectionand

data

extraction.Quality

wasassessed

induplicate

accordingto

a20-point

setofvaliditycriteria.

Studieswere

includedin

thereview

ifthey

achievedavalidityscore

ofatleast

12outofa

maximum

of20(allstudiesusingso

meform

ofcontrolgroup),andin

themeta-analysisif

theyachievedavalidityscore

ofatleast

15

(RCTsonly).Heterogeneitywasnot

investigatedandthemeta-analysiswasnot

precededbytestsofhomogeneity.

15studieswere

included,7provideddata

for

meta-analysis.

ThreeRCTswith259

participants

usedplaquereductionasan

outcomemeasu

re.Dentalhealtheducation

resu

ltedin

asm

allpositivebuttemporary

reductionin

PlaqueIndex:

–0.37(95%

CI

[–0.29,0.59]).Poolingof4RCTs(142

participants)usingthepercentageoftooth

surfaceswithplaqueastheoutcomemeasu

re

alsoproducedapositiveeffect:)11.28(95%

CI[)

6.68,15.53]).

Sprodetal.

(32)

Effectiveness

of

oralhealth

promotion

interventions.

Randomizedandnonrandomized

controlledtrials

were

included.

Generalpopulationandsp

ecific

groupsincluded.

Interventions:

selfinstruction

manuals,self-m

onitoring,programs

forteachingplaquecontrol,oral

hygieneinstruction,videos,

andprogramswithgroups,

disabledpeople

andchildren

tomodifypersonaloralhealth

skills.Outcomemeasu

res:

plaquelevels,gingivalbleeding

scores.

MEDLIN

E(1982–96)andreference

listsofretrievedarticleswere

searched.English

languagepapers

were

selected.It

isnotstatedhow

thepapers

were

selected,orhow

manyoftheauthors

perform

ed

theselection.25%

ofthepapers

(takenatrandom)were

assessed

independentlybyeachofthe

threeresearchers

using

developed

criteria.

38studieswere

describedashavingastrong

design(5

RCTs,

13controlledtrials

and20

quasi-exp

erimental).Studieswere

groupedby

designandinterventionandresu

lts

summarizedin

anarrativeway,tabulatedby

study(nometa-analysisperform

ed).

11studiesfocusedondentalhygienepromotion

(measu

redplaque⁄gingivitis).Accordingto

the

review’s

criteria:6producedapositiveeffect,

4produceduncleareffect,and1produceda

negativeeffect.

Most

effects

were

only

measu

redoverthesh

ort

term

,thuslittle

evidenceis

available

onlong-term

healthgain.

Schou&

Locker

(28)

Effectiveness

ofhealth

educationand

healthpromotion.

Controlledtrials

andotherstudy

designswere

included.

Generalpopulationandsp

ecific

groupsincluded.

Interventions:

lifestyle

interventionsandso

cialand

environmentalapproaches.

Outcomemeasu

res:

plaque

levels,gingivalbleedingscores.

MEDLIN

E(1984–96)andreference

listsofretrievedarticleswere

searched.English

languagepapers

selected.Twooftheauthors

perform

edstudyselection.It

isnot

statedhow

data

extractionand

assessmentwere

perform

ed,

althoughpresp

ecifiedcriteria

were

applied.

Descriptionsofinterventionsand

methodologicalquality

variedgreatlyacross

studies.

Anarrativesu

mmary

waspresented.

Rangesandmeansin

term

sofpercentpositive

changeforthemost

commonoutcomes

were

given,buthow

these

havebeenobtained

isnotclear.14studiesincluded,only

4

studiesmeasu

redoralhygieneand

gingivalhealth,3ofwhichwere

RCTs,

whichindicatedapositiveeffect.

39

Oral health promotion

gorize trials into apparent low or high quality in a

systematic review, and is not supported by empiric

evidence. The meta-analysis is not preceded by tests

of homogeneity. The number of participants in the

meta-analysis is unclear due to discrepancies be-

tween the table and the text. Some of the primary

studies are of poor methodological quality and the

authors discuss the difficulties involved in con-

structing a review from such literature.

Sprod et al. (32)

The authors have stated their research question and

the inclusion criteria. The literature searchwas limited

and may have missed additional studies because only

English language publications were included and only

one database was searched. The search was deliber-

ately limited to articles which may be of relevance to

Wales, and this limitation of the review is recognized

by the authors. It is not reported how many of the

authors performed the selection of studies. There is no

text or tabular description of extracted data for the

included studies (results are described). There is an

assessment of validity with studies grouped by study

design; however, the process of this assessment is not

reported. The authors address the costs of the inter-

ventions, although these costs are not reported in the

text. Given some limitations of the review, the con-

clusions should be viewed with caution.

Schou & Locker (28)

The selection criteria have been stated, but the lit-

erature search was limited and may have missed

additional studies (only English language publica-

tions were included and only one database was

searched). Selection of studies was performed in

duplicate. There is no text or tabular description of

extracted data for the included studies, or a descrip-

tion of the validity assessment of included studies.

The use of a narrative summary for data synthesis is

appropriate, but caution is needed in deciding whe-

ther an intervention was successful.

Brown (4)

The author describes mainly research aspects of

dental health education and oral health promotion.

There are no details of methods of data extraction.

The literature search was limited and may have

missed additional studies (only English language

publications were included and only one database

was searched). A narrative summary and a pictorial

Table

1.Continued

Study

Focus

Inclusioncriteria

Search⁄Studyselection⁄

Quality

assessment⁄D

ata

extraction

No.ofstudiesincluded⁄D

ata

synthesis⁄

Investigationofheterogeneity⁄Findings

(forplaquelevels

and⁄orgingivalbleeding)

Brown(4)

Effectiveness

ofhealth

educationand

healthpromotion.

Evaluativeresearchand

descriptivestudieswere

included.

Participants

ofanyagegroup

included.

Interventionmedia:

pamphlet,classroom,group,

self-instruct,mass

media,

treatm

ent.

Outcomemeasu

res:

plaquelevels,gingival

bleedingscores.

MEDLIN

E(1982–92)andreference

listsofretrievedarticleswere

searched.English

languagepapers

were

selected.It

isnotstated

how

studyselectionanddata

extractionwere

perform

ed.No

validityassessmentis

reported.

14studiesincludedcontrolledstudydesigns.

7studiesmeasu

redplaque,6studiesmeasu

red

gingivalbleeding.Rangesofeffectiveness

for

therelevantoutcomeswere

givenandpercent

effectiveness

wasaveragedacross

each

outcome(notin

aform

almeta-analysis).

Averageim

provements:Plaqueindices–18%,

Bleedingindices–13%.�Itappears

that

one-to-oneinstruction,repeatedcontacts

andparticipantinvolvementare

important

elements

ofinterventionsthathaveachieved

atleast

short-term

positivechangesin

plaqueandbleedingscores�.

CI,confidenceinterval.RCT,randomizedcontrolledtrial.

40

Watt & Marinho

Table

2.

Generalcharacteristicsofcontrolledtrials

publish

edfrom

1995to

2003ontheeffects

ofhealthpromotioninterventionsonplaque⁄gingivitis

Study

Country,

yearstarted

Methods

Participants,setting

(baselinemeasu

res)

Interventions

Outcomes

(finalmeasu

res)

Findings

Nowjack-R

aymer

etal.(22)

USA,1987

Random

allocation

by

homeroom;

single-blind;no

controlgroup;

32%

drop-out

after2years.

14–15-year-old

schoolchildren

(n¼

493)from

highschool.

Bleedingon

probing:

GRI¼

8.5

GRII

¼7.7

Plaque:

GRI¼

1.7

GRII

¼1.7

Instructionforbleeding

assessment

(GRI)

vs.

Instructionforplaque

assessment(G

RII).

Classroom

and

individualtrainingat

start

and1year

(+oralprophylaxis

at1year).

n¼

336after2years.

Bleedingonprobing:

GRI¼

3.5

GRII

¼3.4

Plaque:

GRI¼

1.4

GRII

¼1.3

Nodifferencesbetw

een

groupsforanyoutcome

measu

red(P

¼NS);

substantialreduction

ingingivalbleedingin

both

groupsoverthe

trialperiod(P

¼0.01),

reductionsin

plaque

notsu

bstantial.

Lim

etal.(19)

China

(HongKong),

startingdate

notstated.

Stratifiedrandom

allocation;

single-blind;no

controlgroup;12%

drop-outafter

10months.

25–44years

adults

(n¼

195)

employees

ofacompany.

%bleedingon

probing(SD):

GRI¼

29.5

(20.3)

GRII

¼38.4

(21.0)

GRII

¼30.6

(18.6)

GRIV

¼36.0

(18.6)

%plaque(SD):

GRI¼

54.0

(23.0)

GRII

¼55.0

(23.0)

GRII

¼49.7

(18.5)

GRIV

¼49.5

(20.5)

PersonalInstruction

(GRI)

vs.

Self-education

manual(G

RII)vs.

Video

(GRIII)

vs.

Combination

of2ormore

(GRIV).

Single

sessionsgivenfor

allgroups,

exceptgroupI

(reinforcementgiven).

n¼

171after

10months.

%bleedingon

probing(SD):

GRI¼

21.7

(16.6)

GRII

¼26.9

(17.5)

GRII

¼25.6

(18.0)

GRIV

¼24.3

(18.7)

%plaque(SD):

GRI¼

29.0

(15.8)

GRII

¼30.6

(16.4)

GRII

¼28.6

(13.6)

GRIV

¼30.5

(15.3)

Nodifferencesbetw

een

groupsforanyoutcome

measu

red(P

¼NS);

statisticallysignificant

reductionsin

percentage

plaqueandpercentage

gingivalbleedingin

all

groupsoverthetrialperiod

(P<0.05).

Ivanovic

&Lekic

(12)

Yugoslavia,

starting

date

notstated.

Quasi-random

allocation;

single-blind;

controlgroup;

drop-outafter6

monthsor1year

notstated.

11–14-year-old

schoolchildren(n

notstated).Values

notstatedfor

bleedingindex,

gingivalindex,

plaqueindex

(data

presentedin

figuresonly).

Intensiveinstruction+oral

hygieneinstruments

(GRI)

vs.

Intensiveinstruction+

additionaloralhygiene

instrument(G

RII)vs.

No

suchinterventions(G

RIII).

Educationalsessionsat

start

and6months.

n¼

240after1year.

Valuesnotstatedfor

bleedingindex,

gingivalindex,

plaqueindex

(data

presentedin

figuresonly).

Differencesbetw

een

exp

erimentalandcontrol

groupsfavoredboth

exp

erimentalgroups;

substantialreduction

inall3measu

resin

both

exp

erimentalgroupsover

theexp

erimentalperiod

(followedbyincrease

after6months),butno

changein

controls.

41

Oral health promotion

Table

2.

Continued

Study

Country,

yearstarted

Methods

Participants,setting

(baselinemeasu

res)

Interventions

Outcomes

(finalmeasu

res)

Findings

Littleetal.

(20)

USA,starting

date

not

stated.

Random

allocation;

single-blind;

controlgroup;

8%

drop-out

after4months.

50–70-year-old

periodontalpatients

(nnotstated)from

dentalclinics.

%plaque:

GRI¼

82

%gingivalbleeding:

GRII

¼80

GRI¼

9

GRII

¼10

%bleedingonprobing:

GRI¼

24

GRII

¼26

Group-basedbehavior

modificationintervention

includingskills

training

andselfmonitoring(G

RI)

vs.

no.su

chintervention

(GRII)5-w

eekly,90-m

in

oralhygienesessions.

n¼

98after4months.

%plaque:

GRI¼

76

GRII

¼80

%gingivalbleeding:

GRI¼

4

GRII

¼10

%bleeding

onprobing:

GRI¼

15

GRII

¼21

Significantlygreaternet

improvements

in

exp

erimentalgroupin

whole-m

outh

meanscoresforall

3measu

res.

Fishwicketal.

(6)

UK,1995

Clusterrandom

allocation;

single-blind;

controlgroup;

20%

drop-out

after6weeks.

Healthyvolunteer

employees(n

¼123)

from

workplaces

(n¼

4).Meann

(sites)

bleeding

onprobing(SD):

GRI¼

29.7

(10.2)

GRII

¼25.0

(12.2)

Screening,im

mediate

feedbackanddisplays⁄

campaign(G

RI)

vs.

nosu

ch

intervention(G

RII).

n¼

98after6weeks.

Meann(sites)

bleeding

on

probing(SD):

GRI¼

13.2

(9.2)

GRII

¼26.3

(12.0)

Differencesin

bleedingon

probingbetw

eenexp

erimental

andcontrolgroupsfavored

intervention;reductionsin

bleedingonprobingin

test

group

only

overthe

trialperiod.

Persso

netal.

(24)

USA,nodate

stated.

Stratifiedrandom

allocation;double-

blind;control

group;32%

drop

outafter3years

(allgroups).

60–90-year-old

low-incomeolder

adultswhoso

ught

dentalcare

(n¼

297,

allgroups).

34%

(SD

28%

)mean

prevalenceofbleedingon

probingfor

allgroups.

Relevantcompariso

n:

Cognitivebehavioral

education–2heach

(GRI)

vs.

nosu

ch

intervention(G

RII).

n¼

201after

3years,allgroups.

Decrease

inthe

proportion

ofsites

withbleeding

onprobing:

GRI¼

23%

GRII

¼23%

Nodifferencesin

bleeding

betw

een

exp

erimentaland

controlgroupsoverthe

trialperiod.

42

Watt & Marinho

Willershausen

etal.(36)

Germ

any,

nodate

stated.

Quasi-random

allocation;blind

assessmentnot

indicated;no

controlgroup;

3%

drop-out

after4weeks.

18–55-year-old

healthy

adults(n

¼100)from

Perioclinic.

%plaqueindex(API)

values(SD):

GRI¼

68.9

(12.4)

GRII

¼73.5

(13.6)

%bleedingindex(SBI)

values(SD):

GRI¼

55.9

(12.4)

GRII

¼62.5

(13.2)

Oralhygieneinstruction+

intraoralvideocamera

toprovideextra

inform

ation(G

RI)

vs.

oralhygiene

instructionalone.

n¼

97after4weeks.

%plaqueindex(API)

values(SD):

GRI¼

34.2

GRII

¼53.4

%bleedingindex(SBI)

values(SD):

GRI¼

37.7

(7.2)

GRII

¼51.5

(8.5)

SBIandAPIresu

ltssh

ow

significantdifferences

betw

eenthe2groups

(infavorofemploying

theintraoralcamera

in

oralhygieneinstruction).

Reductionsover

the

trialperiod(m

ore

pronouncedforGRI).

Belloso

etal.

(2)

Venezu

ela,

1994

Random

allocation;

double-blind;no

controlgroup;8%

drop-outafter

6months

Plaqueindex:

GRI¼

1.06(0.35)

GRII

¼0.98(0.39)

GingivalIndex:

GRI¼

1.13(0.35)

GRII

¼1.04(0.40)

6–12-year-old

school-

children(n

¼296)

from

publicand

private

schools.

Instruction⁄supervision⁄

reinforcement⁄stimulation

(GRI)

vs.

Instruction⁄

supervision(G

RII).

n¼

273after6months

Plaqueindex:

GRI¼

0.17(0.21)

GRII

¼1.14(0.46)

Gingivalindex:

GRI¼

0.17(0.14)

GRII

¼1.24(0.49)

Substantialim

provements

observedin

GRIforboth

measu

res.

Reductionsin

both

measu

resonly

forGRI

overthetrialperiod.

Redmondetal.

(26)

UK,1996

Clusterrandom

allocation;double-

blind;control

group;14%

drop-out

after6months

(firstperiodonly).

12-year-old

school-

children(n

¼1063)

from

secondary

schools

(n¼

28).

Mean%

siteswith

plaque(SD):

GRI¼

0.59(0.26)

GRII

¼0.58(0.26)

Dentalhealtheducation

program

(GRI)

vs.

control

(nosu

chprogram)(G

RII).

3lessonsin

a6-m

onth

period.

n¼

915childrenafter

6months.

Mean%

siteswith

plaque

(SD):

GRI¼

0.47(0.28)

GRII

¼0.54(0.26)

Significantreductionin

plaque

levels

infavorofthe

exp

erimentalgroup.

Kowash

etal.

(17)

UK,nodate

stated.

Random

allocation

(mother⁄child);blind

outcomeassessment

indicated;no(true)

controlgroup;21%

dropoutafter3years.

11-m

onth-old

infants

(n¼

228)and

29-year-old

mothers

withlow

socio-

economic

status

population.

DHEdiet(G

RI)

vs.

DHEoral

hygieneinstruction(G

RII)vs.

fluoridetoothpaste(G

RIII)

vs.

DHEcombined.

Eachmothergivencounseling

every

3monthsin

the

1st

and2ndyears,tw

icea

yearin

the3rd

year.

n¼

179childrenafter

3years.

No.ofchildrenwith

gingivitis⁄poororal

hygiene:

GRI¼

3⁄3

GRII

¼0⁄0

GRIII¼

0⁄0

GRIV

¼0⁄6

Nosignificantdifferencesbetw

een

the4groupsforgingivitis

andoral

hygieneoftheinfants.

43

Oral health promotion

Table

2.

Continued

Study

Country,

yearstarted

Methods

Participants,setting

(baselinemeasu

res)

Interventions

Outcomes

(finalmeasu

res)

Findings

Frenkeletal.

(8)

UK

Clusterrandom

allocation;single-

blind;control

group;11%

drop-

outafter6months.

Institutionalizedelderly

(n¼

378)from

nursing

homes(n

¼22).

Meanplaquescoresin

dentate

(SD):

GRI¼

2.15(0.49)

GRII

¼2.10(0.54)

Meangingivitis

scores

indentate

(SD):

GRI¼

1.37(0.41)

GRII

¼1.38(0.51)

Caregiveroralhealtheducation

program

(GRI)

vs.

nosu

ch

intervention(G

RII).

n¼

337after6months

Meanplaquescoresin

dentate

(SD):

GRI¼

1.87(0.49)

GRII

¼2.18(0.53)

Meangingivitis

scores

indentate

(SD):

GRII

¼1.36(0.35)

GRI¼

1.08(0.37)

Thedifferences(intervention

minuscontrol)

indental

plaqueandin

gingivitis

scores

were

significantin

favorofthe

interventionatthe6-m

onth

follow-up

(P<0.001).

TheOHCEprogram

waseffective

inim

provingoralhygiene.

Worthington

etal.(39)

UK,1997

Clusterrandom

allocation;double-

blind;controlgroup;

9%

dropoutafter

4months

(first

periodonly).

10-year-old

school-

children(n

¼310)

from

primary

schools

(n¼

32).

Meanplaquescores:

GRI¼

1.22(0.39)

GRII

¼1.18(0.38)

Dentalhealtheducation

program

(GRI)

vs.

control

(nosu

chprogram)

(GRII).

Four1-h

lessonsin

a

4-m

onth

period.

n¼

281childrenafter

4months.

Plaque(SD):

GRI¼

1.09(0.39)

GRII

¼1.36(0.45)

Significantreductionin

plaquelevels

infavorof

theexp

erimentalgroup.

Blinkhorn

etal.

(3)

UK,starting

date

not

stated.

Clusterrandom

allocation;double-

blind;�control�group;

8%

drop-out(m

others)

and19%

(children)

after2years.

Mothers

(n¼

269)of

1–6-year-old

preschool

children(n

¼334)

from

generaldental

practices(n

¼30).

Valuesforplaque

levels

notrecorded.

DentalHealthEducators

counseledmothers

every

4monthson

toothbrush

ing,

fluoridetoothpaste

andsu

garcontrol(G

RI)

vs.

onetoothbrush

ingcounseling

andfluoridetoothpastetube

(GRII).

n¼

271childrenand

n¼

248mothers

after

2years.

n(%

)childrenwith

plaque(prevalencedata

at2years):

GRI¼

72(53)

GRII

¼82(61)

Nosignificantdifferences

inplaquelevels

were

foundbetw

eengroups.

API,approximalplaqueindex.

DHE,dentalhealtheducation.GR,group.OHCE,oralhealthcare

education.SBI,su

lcusbleedingindex.

44

Watt & Marinho

and tabular description of extracted data ⁄ results are

presented. It is unclear how the data have been

pooled for the average results presented.

Nature and quality of recently publishedpapers

Of the 13 recently published trials, five were set in

schools, four focused on adults either in a clinical or

workplace setting, three targeted older people, and

one, infants (Table 2). All the trials evaluated educa-

tional interventions. The design quality of the trials

was variable. Allocation concealment was clearly des-

cribed in two trials only but blind outcome assessment

was described inmost of the trials and sowere dropout

rates. Design problems in some of the trials included

no controls, there was single blinding and, in the

majority of the studies, follow-up measures were col-

lected over a relatively short time frame. Six studies

collected follow up data beyond a 4–6-month period,

and two studies had follow-up data of shorter periods

(4–6 weeks). A range of differentmethodswere used to

assess plaque and bleeding scores.

Plaque and gingival bleeding outcomes

Due to the variability in the quality of the systematic

reviews undertaken, the findings produced are

somewhat diverse (Table 1). However, it is apparent

that all the reviews have identified that a reduction in

plaque and gingival bleeding were achieved in the

short term in the majority of studies reviewed. Precise

estimates on the magnitude of the improvement are

difficult to assess due to the range and diversity of

outcome measures used. The results of two meta-

analyses indicate a reduction in plaque levels of 32–

37% (14, 15). Very limited evidence supports any

long-term reduction in plaque and gingival bleeding

outcomes. The clinical and public health significance

of short-term reductions in plaque and gingival

bleeding outcomes is not clear. Conflicting conclu-

sions were reached concerning the relative effect-

iveness of different types and styles of educational

interventions. Three of the reviews highlighted the

benefit of implementing more elaborate interven-

tions (4, 28, 32), whereas the other two reviews failed

to detect any difference between simple and more

complex interventions (14–16).

In the recently published trials, positive effects on

plaque and ⁄or bleeding outcomes were produced in

eight studies (2, 6, 8, 12, 20, 26, 36, 39) (Table 2). No

differences in plaque ⁄ and or gingival bleeding levels

between groups were detected in five studies (3, 17,

19, 22, 24). However, in only two of these (3, 24) was a

no-intervention (or control group) employed. Nev-

ertheless, for the other two trials that compared

various approaches (19, 22), reductions in plaque and

gingival bleeding were generally observed in all

groups over the trial period. None of these studies

reviewed produced a negative effect. Although all of

the studies evaluated educational interventions, no

clear indication that any particular type or style of

educational approach was more effective has been

obtained.

Discussion

The importance of critically assessing the evidence

base for health promotion interventions is now

widely accepted. A debate continues, however, over

the most appropriate methodology for assessing dif-

ferent intervention approaches. It has been argued

that experimental trials and effectiveness reviews are

not an appropriate methodology for assessing the

value of public health interventions (27, 31). Although

evaluations can be problematic, given the wide range

of factors influencing lifestyles, and although there

may be difficulties in designing studies such as

randomized controlled trials (RCTs) in community

settings, the failure to use an RCT study design means

that in groups at baseline there may be a serious

imbalance in unknown but important factors that

could influence the outcomes. In addition, unbiased

analysis of the evidence using systematic reviews of

RCTs remains the gold standard methodology for

assessing evidence of effectiveness. Nevertheless,

systematic reviews (like all types of research evi-

dence) require critical appraisal to determine their

validity and to establish whether and how their re-

sults will be used in practice.

This paper has focused on assessing the up-to-date

evidence base for the effectiveness of health promo-

tion interventions in reducing dental plaque and

gingival bleeding. We have identified and critically

appraised five oral health promotion effectiveness

reviews and a further 13 controlled trials published

subsequent to the reviews.

A systematic assessment of the key features of the

reviews revealed several shortcomings in the meth-

odology employed by the reviewers. Areas of partic-

ular concern centered on how well defined the focus

of the reviews was and the comprehensiveness of the

search strategy employed. In particular it is possible

that several studies were not included in the reviews

because they were not published in English. As a

45

Oral health promotion

consequence of the broad focus and variable quality

of the reviews, a spectrum of findings was produced.

A major difficulty found in assessing and summar-

izing the effect of interventions on plaque levels and

gingival bleeding was that different outcome meas-

ures were used in the studies reviewed. Direct com-

parisons between studies are difficult unless stan-

dardized and validated measures are used (14). As it

is not possible to combine the results from different

indices used for plaque (and gingivitis), which

measure the same concepts on different scales, be-

fore combining, the effects would have to be ex-

pressed as standardized values, which have no units.

In our assessment of both the reviews and recently

published papers, it was apparent that all the studies

evaluated educational interventions targeting mostly

schoolchildren or adults in a workplace or clinical

setting. More recent studies also focused on older

people living in residential homes where carers re-

ceived oral health training. None of the studies as-

sessed evaluated policy development or other forms

of health promotion action. Knowledge of the

potential value of non-educational public health

interventions to promote periodontal health is

restricted due to a lack of well designed studies.

What is the effect of educational interventions on

plaque levels and gingival health? Due to the broad

focus, variable quality of the reviews, and the spec-

trum of findings produced, a precise quantitative

estimate of the intervention effect is not available.

However, it appears that in the short term, up to

6 months post-intervention, substantial reductions in

plaque levels can be expected. Very few longer term

follow-ups have been undertaken so it is impossible

to determine whether these short-term improve-

ments in plaque levels are sustained. Evidence from

other reviews of behavioral change interventions

indicate that short-term changes are not sustained in

the longer term unless an alteration has occurred in

the social environment to maintain the new behav-

iors (30). The clinical and public health significance

of short-term reductions in plaque levels and gingival

bleeding is unclear. Three of the systematic reviews

concluded that there was no convincing evidence

that school-based educational programs had any ef-

fect on plaque levels (14, 15, 32). However, the

majority of recent studies conducted in schools have

shown a positive effect on plaque outcomes (2, 12, 26,

39). Nevertheless, no pooling of the results of the

individual trials assessed in this paper was attempted.

A quantitative synthesis should compile all the

available evidence, but only studies published sub-

sequent to the existing reviews have been considered

in this paper. Very limited evidence exists on the

costs of intervention programs. Many of the educa-

tional interventions relied heavily upon professional

input, which tends to be very costly.

This study has assessed the up-to-date evidence

base for health education interventions aiming to

reduce plaque and gingival bleeding. Five oral health

promotion effectiveness reviews have been critically

assessed and a comprehensive and thorough search

and assessment of recently published studies in this

area has been undertaken. Although every effort was

made to identify and locate relevant papers, some

studies have not been assessed (10, 11, 13, 33). It is

unlikely, however, that these studies would radically

alter the overall findings of this paper. However,

interventions whose prime aim was to improve other

health outcomes were also not included in this re-

view. For example, smoking cessation interventions

may have a significant impact on plaque control and

gingival bleeding.

In conclusion, this study has shown that all the

reviews and individual studies assessed evaluated

health education interventions. Reductions in plaque

and gingival bleeding were achieved in the short-

term in the majority of studies reviewed. The clinical

and public health significance of these changes are,

however, questionable. Future studies should use

longer follow-up periods to assess whether short-

term beneficial changes are sustained. Better quality

evaluation is required of other forms of oral health

promotion action to promote periodontal health.

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