Periodontology 2000, Vol. 22, 2000, 133–153 Copyright C Munksgaard 2000Printed in Denmark ¡ All rights reserved

PERIODONTOLOGY 2000ISSN 0906-6713

The conservative approach in thetreatment of furcation lesionsMARCELLO CATTABRIGA, VINICIO PEDRAZZOLI & THOMAS G. WILSON JR.

Molars are the tooth type demonstrating the highestrate of periodontal destruction in untreated disease(50) and suffer the highest frequency of loss for peri-odontal reasons (3, 72). For the purposes of thischapter, furcation involvement is defined as bone re-sorption and attachment loss in the interradicularspace that results from plaque-associated peri-odontal disease. Such a condition is reported to con-siderably increase the risk for tooth loss (24, 32, 57–59, 80, 99, 102). Therefore, furcation defects repre-sent a formidable problem in the treatment of peri-odontal disease, principally related to the complexand irregular anatomy of furcations. Moreover, theresponsiveness to therapy may be complicated bythe presence of a greater radicular surface poten-tially offered to bacterial toxins and calculus build-up, as compared to defects surrounding single-root-ed teeth. Once the lesion has established, the dis-crepancy in extent between the root surfaces and theperiodontal soft tissues facing the bacterial insultmay be responsible for a reduced healing response.Finally, the distal location in the arch and the diffi-cult access may conceivably impair both self-per-formed and professional plaque control proceduresin the furcation area, limiting their effectiveness.

The principles of therapy of furcation involvementmay be discussed under three major headings: con-servative, resective and regenerative. It must beborne in mind, however, that the borderline betweenconservative and resective terms sometimes doesnot lend itself to a sharp definition, as it is ratherdifficult in a clinical setting to completely separateconservative and resective treatments. This is espe-cially true for furcation involvements. Resective pro-cedures must sometimes be performed in order toattain a result which can eventually be consideredmore conservative. For instance, tunnel preparationis an example of conservative therapy carried out toavoid more radical and resective forms of treatmentfor class II and III furcation involvements. However,tunnel preparation is often accomplished at the ex-

133

penses of bone and tooth substance within the fur-cation area to gain enough space for interdentalcleaning devices. Root amputation represents an-other form of resective procedure used often for con-servative purposes.

The conservative approach defined here com-prises surgical and nonsurgical treatment employedto debride the furcation area excluding regenerationand root separation procedures. These treatmentsare sometimes accompanied by procedures that maychange the tooth anatomy and the surrounding peri-odontal structures to improve access for plaque con-trol, although they do not imply crown restorations.

An array of therapeutic procedures have been sug-gested by clinicians with the aim of improving theprognosis of furcated teeth. The scope of this reviewis to discuss the literature on the conservative ap-proaches in the treatment of furcation involvements.

Epidemiology

The prevalence of severe periodontitis has been re-ported to vary from 5% to 20% of the different popu-lations investigated according to the criteria em-ployed to measure extent and amount of periodontaldestruction (70, 71).

Longitudinal studies conducted to describe theprogression of untreated periodontitis have shownthat the majority of sites losing attachment belongto a small subset of the population (13, 14, 25, 50,52). Molars appear to be the most affected teeth (50)and the tooth type most frequently lost (3, 55, 72).

Despite the well-documented evidence that peri-odontal therapy is effective in halting disease pro-gression (42, 49, 80), tooth loss appears to be an un-avoidable event even in some otherwise successfullytreated patients, although at a considerably lowerannual rate (0.05–0.1%) (4, 24, 32, 57, 102) comparedwith that of untreated populations (0.14–0.38%) (3,11, 52, 72). Molars again represent the tooth type re-

Cattabriga et al.

sponding least favorably to therapy (36, 54, 67) andare at greater risk for extraction compared with othertooth types (24, 32, 57, 80, 99, 102).

The greater rate of mortality observed with maxil-lary and mandibular molars may partly be explainedby the presence of furcations. When the latter areinitially affected by the destruction of periodontalsupport, the peculiar anatomical configuration, to-gether with the distal location, are likely to acceler-ate the rate of disease progression, whereas the con-trol of infection by the patient becomes moretroublesome. Indeed, an association between clin-ical or radiographic detection of furcation involve-ment, and increased risk of tooth loss has been re-peatedly demonstrated (24, 32, 57–59, 80, 102).

Prevalence of furcation involvement

Sparse information is available regarding the preva-lence of naturally occurring involvement of the mo-lar furcation area in the general population in epide-miological surveys. Most of the available data are de-rived from studies based on observations performedin dry skulls (45, 46, 85, 90–92, 96). These resultsmust be interpreted cautiously: the number of ob-servations is relatively small and the anatomicalspecimens belong to populations that are ethnicallyand socially quite characterized. Thus, the resultsfrom these studies may not apply to other ethnic andsocial cohorts.

In the study by Volkansky & Cleaton-Jones (96) on43 dry mandibles of South African Bantu people30.9% of molar teeth present had furcation involve-ment. Tal (92) examined 100 dry mandibles fromSouth African skulls and found that 85.4% of man-dibular molars presented with osseous resorption inthe furcation area. He reported also that the degreeof furcation involvement, as expressed in terms ofhorizontal depth of the osseous defect, increasedwith increasing age. In a subsequent study on man-dibular molars, Tal & Lemmer (91) confirmed the

Table 1. Frequency of furcation involvement in patients referred for periodontal treatment. Adapted fromoriginal data

Numbers (%) of molars with furcation involvement

Authors Maxillary Mandibular Diagnostic method

Hirschfeld & Wassermann (32) 858/2217 38.7% 597/2054 29.0% Clinical

McFall (57) 95/378 25.1% 60/377 15.9% Clinical

Goldman et al. (24) 454/870 52.2% 169/865 19.5% Radiographic

Wood (102) 87/205 42.4% 77/220 35.0% Radiographic/clinical

134

finding that moderate and severe involvements arepredominant in older adults, first molars being moreaffected than second molars.

Bjorn & Hjort (6) assessed longitudinally theradiographic prevalence, degree and development ofbone destruction in mandibular molar furcations ina sample of 221 factory workers observed over aperiod of 13 years. The prevalence of furcation in-volvement steadily increased from an initial value of18% to 32% at the end of the observation period.Third and second molars had higher frequencies ofadvanced destruction than first molars.

Additional data are provided by investigations en-rolling periodontally diseased subjects who eitherwere referred for or spontaneously sought peri-odontal care (24, 32, 57, 88, 102). Therefore, thefindings from these surveys may not be used to de-rive conclusions about the general population.Maxillary molars are more frequently affected thanmandibular molars, although the prevalence valuesmay greatly differ. The prevalence of involvement inthe furcation area in maxillary and in mandibularmolars range from 25% to 52% and from 16% to 35%,respectively (Table 1). Svardstrom & Wennstrom (88)studied in detail the prevalence of furcation involve-ment in a group of 222 patients referred for peri-odontal treatment. They reported that, from the ageof 30 years onward, about 50% of molars in the max-illa show at least 1 furcation site with deep involve-ment, while in the mandible a similar prevalencewas first observed after the age of 40. Periodontaldestruction was most frequently observed at the dis-tal aspect of the first and second maxillary molars(53% and 35%, respectively). In the mandible thebuccal and lingual entrances of furcations wereaffected with similar frequencies.

Furcation involvement is more frequently de-tected in smokers (72%) than in nonsmokers (36%);the calculated odds ratio for a smoker to have fur-cation involvement in one molar is 4.6 (64). It hasalso been demonstrated that molars with crowns or

The conservative approach in the treatment of furcation lesions

Fig. 1. Influence of ill-fitting restorations in determining ically, an abscess formation in the furcation area was evi-furcation involvement. A. Radiograph of a second man- dent. C, D. Radiograph and clinical photo showing thedibular molar presenting with a mesial overhanging same tooth 7 years after a tunnel procedure. Note in D thecrown margin without furcation involvement. B. The overhang of the new crown, probably responsible for thesame tooth 1 year later after a new bridgework was in- furcation involvement.serted: note the presence of furcation involvement. Clin-

proximal restorations have significantly higher per-centages of furcation involvement (52–63%) com-pared with molars without restorations (39%) (98)(Fig. 1).

Classification of furcation lesions

Different clinical methods for classifying the extentof furcation involvement have been proposed. Glick-man (23) initially devised a four-degree classificationbased on the extent of destruction of periodontaltissues within the furcation. Ramfjord & Ash (79)have described an index for evaluating the depth ofinvolvement using 2 mm increments of periodontalprobing measurements. With degree 1 the probepenetrates horizontally between the roots up to 2mm; with degree 2 more than 2 mm and with degree3 the probe penetrates the furcation all the waythrough to the opposite entrance.

135

Hamp et al. (29) have proposed the same ap-proach as Ramfjord & Ash with the exception ofusing 3 mm increments to describe the 3 classes ofinvolvement (Fig. 2), while Tarnow & Fletcher (93)have proposed a subclassification which takes intoaccount the vertical extent of the lesion in anattempt to better describe its severity.

Reproducibility and reliability ofdiagnosis and diagnostic measures

Probing

Vertical measurements along the roots adjacent tofurcation lesions have been shown to be reproduc-ible in facial sides of maxillary molars and in facialand lingual sides of mandibular molars (62). The in-ter-examiner reproducibility, however, decreaseswith increasing pocket depth and increasing rootseparation because, as the probe penetrates deeper,

Cattabriga et al.

Fig. 2. Dry skull specimens depicting class I (A), 2 (B) and3 (C) furcation involvements

it is more difficult to maintain contact with the rootsurface. Reproducibility of horizontal measurementsdoes not seem to be as satisfactory as with verticalrecordings (62).

The reliability of vertical measurements taken atthe deepest interradicular pocket depth is very poor,however, as the probe invariably penetrates the fur-cation connective tissue to an average depth of 2.1mm (63), as shown in histological sections. Otherauthors have looked for a reliable correlation be-tween the clinical diagnosis of furcation involvementand the extent of destruction visualized after flap re-flection. Zappa et al. (106) used both the Ramfjordand Hamp indices to compare horizontal clinical as-sessments indicated in grades of severity with thoserecorded after surgical exposure. Regardless of theuse of a calibrated or noncalibrated Nabers probe(Fig. 3) the results showed frequent over- and under-estimation. On the contrary, Eickholz & Staehle (19)and Eickholz (20) found satisfactory reliability interms of degree of furcation involvement when com-paring clinical presurgical and intrasurgical meas-urements, except for disto-palatal sites where onlymoderate agreement between the two types of re-cordings was noted. The difficulties in accurately de-

136

termining the extent and severity of furcation in-volvement shown by some of the former studies isnoteworthy, as it has been demonstrated that clini-cians base treatment options and strategies on theclinical assessment of the degree of interradiculardestruction (65). Errors in diagnosing the extent andseverity of furcation involvement may lead to errorsin the choice of treatment.

Radiographic diagnosis

Radiographic diagnosis of furcation involvement isusually easier to perform in mandibular molars, asthe superimposition of the palatal root on the radio-graph film may conceal the actual bony morphologyin the interradicular area in maxillary molars. Harde-kopf et al. (30) have claimed that the identificationof a triangular radiographic shadow (furcation ar-row) on roentgenograms of maxillary molars couldbe a useful indicator for presence of a class 2 or 3furcation involvement. Although the association ofthe furcation arrow image with class 2 or 3 furcationinvolvement was significant mesially and bucallywhen compared with uninvolved furcations, the ab-sence of the furcation arrow image did not necess-

The conservative approach in the treatment of furcation lesions

Fig. 3. Use of a curved probe (Naber’s probe) for clinical margin in order to locate the furcation entrance (A).assessment of furcation involvement. The probe’s tip is Subsequently the probe is moved into the interradicularinitially applied on the root trunk just under the gingival space (B).

arily mean absence of a bony furcation involvement.The presence of a radiolucent interradicular areamay not always be the result of a true furcation in-volvement due to periodontal reasons, as traumafrom occlusion and endodontic pathoses due to ac-cessory patent canals (28) communicating with theinterradicular space may be responsible for bone re-sorption resembling that occurring during peri-odontitis.

Ross & Thompson (84) detected furcation involve-ment more frequently in maxillary molars by radio-graphic examination than clinical inspection,whereas the opposite was true for mandibular mo-lars. They also observed that a more accurate fur-cation involvement diagnosis was accomplished bycombining radiographic and clinical examinations.

The conservative approachin the treatment of furcationinvolvement

Longitudinal long-term clinical surveys have shownthat periodontal therapy is effective in halting thedisease process in nearly every patient and site (18,27, 40, 97). These results have been achieved inde-pendent of the type of surgical and nonsurgical ther-apy performed, provided that supportive periodontaltherapy was administered on a regular basis (100).However, longitudinal prospective (36, 54, 67) andretrospective (24, 32, 57, 83, 84, 99, 102) studiesshowed that, in molars with furcation involvement,the results are not as satisfactory as those obtainedfor single-rooted teeth or nonfurcated molars.

137

Nevertheless, these studies showed acceptable long-term functional survival rate for furcated molars, in-dicating that the presence of furcation involvementis not per se a reason for assigning a questionable tohopeless prognosis to these teeth.

Studies based on tooth mortality (Table 2)

Ross & Thompson (83) followed 387 maxillary molarswith radiographic evidence of furcation involvementin 100 patients with chronic destructive periodontaldisease for a period ranging between 5 and 24 years.The treatment consisted of a combination of pro-cedures including scaling, curettage, occlusal correc-tion by coronal reshaping, periodontal surgery ofsoft tissues and oral hygiene instructions. No oss-eous surgery was performed; 305 of the 387 (84%)molars had a questionable to poor prognosis at thebeginning of the study: at least one root with a mini-mum bone loss of 50%. A total of 341 (88%) were stillfunctioning efficiently without pain at the end of thestudy, whereas the remainder had been extracted atvarious time intervals. However, 15 (33%) of the 46teeth extracted had been in place for 11–18 years and10 (22%) for at least 6 years.

The retrospective studies by Hirschfeld & Wasser-man (32), McFall (57), Goldman et al. (24) and Woodet al. (102) are centered on long-term observationsof multiple forms of periodontal therapy. The qualityof response to treatments by an individual patientwas evaluated considering the number of teeth lostduring the observation period. This allowed for theclassification of patients into three categories: well-maintained group (lost 0–3 teeth), downhill group(lost 4–9 teeth) and extremely downhill group (lost

Cattabriga et al.

Tab

le2.

Mo

lars

’m

ort

alit

yin

lon

g-te

rmsu

rvey

so

nsu

rgic

alan

dn

on

surg

ical

per

iod

on

tal

trea

tmen

t

Too

thm

ort

alit

yin

mo

lars

Inte

rval

ssu

pp

ort

ive

Foll

ow-u

pN

um

ber

of

per

iod

on

tal

ther

apy/

Wit

hfu

rcat

ion

Wit

ho

ut

furc

atio

nSt

ud

ysu

bje

cts

Mea

nye

ars

(Ran

ge)

Trea

tmen

tsu

pp

ort

ive

per

iod

on

tal

care

invo

lvem

ent

invo

lvem

ent

Ro

ss&

Th

om

pso

n(8

3)10

0N

ot

avai

lab

le(5

–24)

Sup

ragi

ngi

val

scal

ing,

cure

ttag

e,3

mo

nth

s46

/387

*N

ot

avai

lab

leo

cclu

sal

adju

stm

ents

,o

ral

hyg

ien

e12

%in

stru

ctio

n,

gin

givo

pla

sty,

gin

give

ctom

y,ap

ical

lyp

osit

ion

edfl

ap,

no

oss

eou

ssu

rger

y

Hir

sch

feld

&W

asse

rman

(32)

600

22(1

5–53

)Su

bgi

ngi

val

scal

ing,

gin

give

ctom

y,fl

apN

ot

spec

ified

460/

1455

191/

3016

surg

ery,

root

amp

uta

tion

,32

%6%

hem

isec

tion

,o

cclu

sal

adju

stm

ents

McF

all

(57)

100

19(1

5–29

)Su

pra

gin

giva

lsc

alin

g,su

bgi

ngi

val

Th

em

ajo

rity

3–6

mo

nth

s88

/155

46/6

00sc

alin

g,o

cclu

sal

adju

stm

ents

,o

ral

57%

8%h

ygie

ne

inst

ruct

ion

,gi

ngi

vect

omy,

gin

givo

pla

sty,

oste

ctom

y,os

teop

last

y

Go

ldm

anet

al.

(24)

211

22.2

(15–

34)

Sup

ragi

ngi

val

scal

ing,

sub

gin

giva

l3–

6m

on

ths

270/

630

190/

1112

scal

ing,

gin

give

ctom

y,gi

ngi

vop

last

y,43

%17

%ap

ical

lyp

osit

ion

edfl

ap,

scal

ing,

cure

ttag

e,o

cclu

sal

adju

stm

ents

Wo

od

etal

.(1

02)

6313

.6(1

0–34

)Su

pra

gin

giva

lsc

alin

g,su

bgi

ngi

val

No

tsp

ecifi

ed38

/164

36/2

61sc

alin

g,sc

alin

gan

dro

ot

pla

nin

g,23

%14

%cu

rett

age,

occ

lusa

lad

just

men

ts,

gin

give

ctom

y,fl

apsu

rger

y,fl

apcu

rett

age,

osse

ous

graf

tin

g,ro

otam

pu

tati

on

Wan

get

al.

(99)

248

(8)

Scal

ing

and

roo

tp

lan

ing,

poc

ket

elim

-N

ot

spec

ified

20/8

710

/78

inat

ion

surg

ery,

mod

ified

Wid

man

flap

,23

%13

%cu

rett

age

Surg

ical

pro

ced

ure

sin

ital

ics.

*O

nly

max

illa

rym

ola

rs.

138

The conservative approach in the treatment of furcation lesions

10–23 teeth). Such subdivision has been maintainedin this review to construct a table reporting toothmortality rate for furcated molars (Table 3).

Hirschfeld & Wasserman (32) examined retrospec-tively the periodontal conditions of 600 patients whohad been previously treated in a private practice for15 to 53 years (mean 22 years). A total of 76.5% ofthe patients had been initially classified as havingadvanced periodontal disease, whereas 16.5% haddisease of intermediate severity and only 7% ex-hibited early signs of periodontitis. The periodontaltreatment rendered throughout the years consistedof subgingival scaling, gingivectomy and flapsurgery. Root amputation (17 teeth) or hemisectionswere performed as well. Patients were subjected toperiodic maintenance, and subgingival scaling wascarried out when deemed necessary. Evaluation ofresponse to therapy was based on the number ofteeth lost during the observation period. The well-maintained group accounted for 499 (83.2%), thedownhill group 76 (12.6%) and the extremely down-hill group 25 (4.2%) of the sample investigated. Al-though the majority of patients had been initiallyclassified as having advanced disease, most of themresponded favorably to therapy, leaving a small sub-group of patients whose periodontal condition con-tinued deteriorating despite treatment. These dataconfirmed epidemiological findings reported fromstudies on the natural course of the disease, attestingthat a small subfraction of the population accountsfor the majority of periodontal destruction recorded(13, 14, 50, 52). During the maintenance phase, 7.1%of all teeth were lost for periodontal causes; 460 of1455 (31.6%) molars presenting with furcation in-volvement were lost, the majority belonging to thedownhill and extremely downhill groups, whereasonly 19.3% belonged to the well-maintained group.Overall, the proportion of lost molars with furcationinvolvement was about 5-fold that of molars withoutfurcation involvement.

McFall (57) analyzed a sample of 100 patients whohad been treated and maintained for 15 years orlonger (average duration 19 years, range 15 to 29years). Severity of periodontal disease was classifiedaccording to the criteria of Hirschfeld & Wasserman(32): 36 of 100 were diagnosed as having advanceddisease, 53 presented with intermediate degree of se-verity and 11 had early signs of disease. Therefore, thisstudy population contained fewer advanced casesthan those monitored by Hirschfeld & Wasserman(32). All patients were treated similarly during theperiod of initial preparation with supragingival andsubgingival scaling, occlusal adjustment and oral hy-

139

Tab

le3.

Mo

lars

’m

ort

alit

yra

tes

acco

rdin

gto

ind

ivid

ual

resp

on

seto

trea

tmen

tin

lon

g-te

rmsu

rvey

so

nsu

rgic

alan

dn

on

surg

ical

ther

apy

Wel

lm

ain

tain

edD

own

hil

lE

xtre

mel

yd

own

hil

l

Stu

dy

No.

of

Wit

hfu

rcat

ion

Wit

ho

ut

furc

atio

nN

o.o

fW

ith

furc

atio

nW

ith

ou

tfu

rcat

ion

No.

of

Wit

hfu

rcat

ion

Wit

ho

ut

furc

atio

np

atie

nts

invo

lvem

ent

invo

lvem

ent

pat

ien

tsin

volv

emen

tin

volv

emen

tp

atie

nts

invo

lvem

ent

invo

lvem

ent

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

(%)

Hir

sch

feld

&W

asse

rman

(32)

499

(83)

219/

1132

(19)

46/2

647

(2)

76(1

3)16

5/23

5(7

0)94

/303

(31)

25(4

)75

/88

(85)

52/6

6(7

9)

McF

all

(57)

77(7

7)18

/65

(28)

25/5

30(5

)15

(15)

39/5

6(7

0)12

/52

(23)

8(8

)31

/34

(91)

9/18

(50)

Go

ldm

anet

al.

(24)

131

(62)

56/3

35(1

7)45

/771

(6)

59(2

8)13

7/20

6(6

6)98

/261

(37)

21(1

0)77

/82

(94)

47/8

0(5

9)

Wo

od

etal

.(1

02)

54(8

6)21

/126

(17)

No

tav

aila

ble

7(1

1)12

/28

(43)

No

tav

aila

ble

2(3

)5/

10(5

0)N

ot

avai

lab

le

Ad

apte

dfr

om

ori

gin

ald

ata.

Cattabriga et al.

giene instruction. Treatment consisted primarily ofgingivectomy and gingivoplasty. Infrabony defectswere treated with ostectomy and osteoplasty wherepocket elimination was deemed feasible. Root ampu-tation was performed on only 5 teeth. Other molarswith furcation involvement were treated surgically ormaintained with open or closed curettage. The ma-jority of the patients had been under a maintenanceregime at 3-, 4- or 6-month intervals. During thisperiod, when indicated, patients were rescheduled forsurgical procedures. The study population, divided onthe basis of tooth loss, was distributed in the followingmanner: well-maintained group 77, downhill group15 and extremely downhill group 8. Periodontal dis-ease was the cause of 259 teeth (9.8%) lost; 56.7% ofteeth with furcation involvement were lost during theobservation period, and the well-maintained grouphad only 27% of the furcation involvement teeth ex-tracted. Of 600 molars without furcation involvement,only 46 (7.6%) were lost. Remarkably, molars with fur-cation involvement had functioned before extractionfor an average of 14 years, 10.5 years and 9 years in thewell-maintained, downhill and extremely downhillgroups, respectively.

Goldman et al. (24) examined the clinical records of211 patients treated and maintained for 15 to 34 years(average time 22.2 years). Treatment rendered con-sisted of supragingival and subgingival scaling, oralhygiene instruction and occlusal adjustment whenneeded. Surgery consisted mainly of gingivectomy orgingivoplasty, and in few cases a flap or open curet-tage was performed. According to their response totreatment, patients were classified as follows: well-maintained group 131 (62%), downhill group 59(28%), and extremely downhill group 21 (10%). At notime was osseous tissue removed. Furcations weretreated by gingivectomy or gingivoplasty or an apic-ally positioned flap and maintained by scaling andcurettage. In only five cases was root amputation per-formed. Of the teeth initially present, 13.4% were lost.Of 630 teeth with initially diagnosed furcation in-volvement, 270 were extracted (43.5%), whereas in thewell-maintained group the number of lost teethhaving furcation involvement was 56 of 335 (16.7%).Among nonfurcated molars, 190 of 1112 (17.0%) werelost during the study.

Wood et al. (102) studied 63 patients who had re-ceived periodontal treatment for at least 10 yearspreviously (average duration 13.6 years, range 10–34). Therapy consisted initially of supragingival andsubgingival scaling accompanied by oral hygiene in-structions. Subsequent surgical therapy includedgingivectomy, flap surgery, flap curettage, osseous

140

contouring, osseous grafting and root amputation.Maintenance intervals differed greatly among pa-tients, from ∞6 to ±9 months. According to responseto therapy patients were divided as follows: well-maintained group 54 (85.7%), downhill group 7(11.1%) and extremely downhill group 2 (3.2%). Dur-ing the maintenance period, 5% of teeth initiallypresent were lost due to progressing periodontal de-struction. Thirty-eight (23.2%) of the initially fur-cated teeth were lost. In the well-maintained group,21 of 126 (16.6%) teeth with furcation involvementwere lost. Among the 261 molars without furcationinvolvement, 36 were extracted (13.8%).

In a study on 24 patients treated either with mech-anical or surgical procedures, Wang et al. (99) dem-onstrated that molars with furcation involvementwere 2.54 times more likely to be lost compared withteeth without furcation involvement during the 8-year maintenance period.

The above-mentioned longitudinal studies revealthat molars with furcation involvement are definitelymore prone to loss than nonfurcated molars (Table2). However, the number of molars having furcationinvolvement lost for periodontal reasons may belower, as some teeth, mainly third molars, mighthave been extracted for other causes related to theaccomplishment of comprehensive treatment plans,such as extrusion due to absence of the antagonisttooth or poor compatibility with prosthetic recon-struction. On the other hand, some furcated molarswere extracted in these studies at the commence-ment of treatment and hence were not included inthe computation of survival rates. Moreover, thepresence of furcation involvement might have beenoverlooked due to diagnostic misjudgment. There-fore the figures reported in the surveys may not cor-respond to the actual mortality rates for molars withfurcation involvement.

The percentages of initially furcated molars lostduring the observation periods of the studies variedfrom 11.8% to 56.7% (24, 32, 57, 83, 99, 102). However,the well-maintained groups, representing the vastmajority of the patients enrolled in the surveys (rang-ing from 62% to 85.7%), had considerably lower ratesof molars with furcation involvement extracted(16.7% to 27.3%) compared with patients in the ill-re-sponding groups (Table 3). This finding is in accord-ance with the assumptions that the majority of pa-tients in these studies, probably because of lower sus-ceptibility to disease or effective plaque control,responded well to periodontal treatment. Thus, mo-lars with furcation involvement do not seem to benecessarily associated with a questionable prognosis,

The conservative approach in the treatment of furcation lesions

because most of them remained in the well-main-tained groups for many years. Moreover, many of thelost furcated molars had been claimed to functionwell for a considerable length of time before their ex-traction. However, despite the tenet that furcatedteeth can be successfully treated and maintained incompliant and less susceptible individuals, the pres-ence of furcation involvement must still be con-sidered a true risk factor, as clearly shown by the cal-culation, for each response-to-treatment category, ofthe odds ratios for extraction between molars withand without furcation involvement in the long-termstudies from which data for such computations areavailable (24, 32, 57). The meta-analysis (Table 4)clearly indicates that furcated teeth have significantlygreater chances to be lost than nonfurcated molars,regardless of the response to treatment, with the soleexception of the extremely downhill group in the sur-vey by Hirschfeld & Wasserman (32).

Unfortunately, no long-term investigation re-ported in Table 2 provides data about the frequencydistributions of furcation involvement according tothe extent and severity of destruction nor do theyreport as to the choice of treatment in relation to thedegree of involvement. It is therefore impossible todraw any conclusion from these articles about theefficacy of the various periodontal treatments ap-plied in accordance with the initially diagnosed se-verity of involvement. More recently, other studieshave been carried out to investigate the effectivenessof specific periodontal treatments on furcations withdifferent degrees of destruction. This issue is dis-cussed in another section.

Studies based on clinical measurements, microbialparameters and efficacy of root instrumentation

The above-mentioned retrospective longitudinalstudies have all based their conclusions on tooth

Table 4. Odds ratio for extraction between furcated and nonfurcated molars calculated for eachresponse-to-treatment category using data from Table 3

Study Well maintained Downhill Extremely downhill

Hirschfeld & Wasserman (32) Odds ratio 13.56 5.24 1.5595% confidence interval 10.39–17.66 3.04–9.01 1.42–1.68z 19.35* 5.98* 1.04

McFall (57) Odds ratio 7.73 7.64 10.3395% confidence interval 4.26–14.01 3.35–17.41 2.63–40.44z 6.74* 4.84* 3.35*

Goldman et al. (24) Odds ratio 3.23 3.30 10.8195% confidence interval 2.16–4.83 2.26–4.80 4.46–26.15z 5.73* 6.21* 5.28*

* P∞0.05.

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mortality. Shorter prospective studies, owing to thelimited duration of the period of investigation, havefocused on the response to treatment based onmeasurements of clinical parameters such as attach-ment level and pocket depth rather than tooth mor-tality. A few studies have also investigated the effectsof periodontal therapy on the subgingival microfloraand the distribution of calculus deposits.

Two 2-year prospective studies (54, 67) investi-gated the effects of root debridement and plaquecontrol in adult periodontitis patients. Molar fur-cation sites responded less favorably to treatmentcompared with molar flat surfaces and non-molarsites. This was revealed by higher mean bleeding onprobing scores, higher mean loss of attachment andless reduction of probing depth. Among the deepestsites (initially Ø7 mm), 21–38% of molar furcationslost attachment as compared with 1.7–7% of the mo-lar flat surfaces and 6–11% of the non-molar sites.Similar trends have been observed in other indepen-dent researches. Kaldahl et al. (36) found that fur-cations of molar teeth always responded less favor-ably than other site groupings to surgical peri-odontal therapy in terms of attachment levelmeasurements, regardless of the initial probingdepth. Finally, Wang et al. (99) reported that during 8years of supportive periodontal therapy, molars withfurcation involvement lost an average of 1.24 mmin attachment level, while molars without furcationinvolvement lost only 0.6 mm.

The comparatively poorer clinical response of mo-lar furcated sites is also reflected in the microbiologi-cal outcome observed in a study conducted by Looset al. (53). These authors monitored for 52 weeks theclinical and microbiological effects of plaque controland root debridement with ultrasonics at 24 non-molar sites and at 31 grade II molar furcation siteswith probing depth Ø5 mm in 11 patients. Through-out the study, numbers and percentages of spiro-

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chetes, total anaerobic colony-forming units andnumbers of Porphyromonas gingivalis were alwayshigher in furcations than in non-molar sites. Thisfinding may be accounted for by the difficulty inachieving complete debridement in furcation sites.Indeed, it has been demonstrated that more residualcalculus is left after debridement in furcation areasthan on other root surfaces (22, 73, 74, 101). Parashiset al. (74) studying 30 mandibular molars scheduledfor extractions with class II and III furcation involve-ment and Calculus Index Ø2 (78) showed that themean values of residual calculus were statisticallylower for the external surfaces than for furcationareas when using a closed approach.

The influence of furcation anatomy

The reduced rate of success experienced with theconservative approach in the treatment of furcationinvolvement seems to result from the incomplete re-moval of hard and soft debris present in the interrad-icular area owing to the peculiar anatomy of the fur-cation space (cervical enamel projections, bifurca-tion ridges, convexities, concavities and furcationentrance dimension) (8, 9, 17, 33–35, 87).

Svardstrom & Wennstrom (87) have described indetail the topography of the furcation area in themaxillary and mandibular first molars. By im-plementing a photogrammetric method, theseauthors plotted the interradicular area to obtainthree-dimensional contour maps. The complexity ofthe internal surfaces of the furcation areas was out-lined showing an array of small peaks, ridges andpits.

Bower (9) found that, in maxillary first molars, thefurcal aspect of the root was concave in 94% ofmesiobuccal roots, 31% of distobuccal roots and 17%of palatal roots. Moreover, he observed that the con-cavity of the furcal aspect was present in 100% and99% of mandibular mesial and distal roots, respec-tively. Once the plaque front has reached the fur-cation area, these configurations render the cleans-ing procedures quite awkward.

Furcation entrance dimension is of paramountimportance for successful therapy, as it influencesthe feasibility of gaining access to the interradiculararea with mechanical instruments, as shown by Mat-ia et al. (56) and Parashis et al. (74), who found thatthe amount of residual calculus was related to thewidth of the furcation entrance when open rootplaning was performed.

Furcation entrances that are not amenable toaccess by mechanical instruments are a quite com-

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mon finding. In a study conducted by Bower (8),the furcation entrance diameter in a sample of 114maxillary and 103 mandibular first molars wasfound to be narrower than the width of commonlyused periodontal curettes in 58% of the furcationsexamined. A later study by Chiu et al. (17) foundin 185 Chinese first maxillary molars that furcationentrance dimension Æ0.75 mm were present in79% of buccal, 39% of mesial and 43% of distal en-trances. In 178 mandibular molars, furcation en-trances Æ0.75 mm were detected in 36% and 47%of buccal and lingual aspects, respectively. Half ofall furcation entrance dimensions of these firstmolars were less than the blade width of a newGracey curette. Hou et al. (35) examined the fur-cation entrance dimension of 89 Chinese maxillarymolars (49 first and 40 second molars) and 93mandibular molars (50 first and 43 second). Themajority of furcation entrances in second molarshad smaller dimensions than the width of a Graceycurette (0.76 mm), although they were larger thanthe average dimension of a new standard ultra-sonic tip. Ultrasonic inserts may then have easieraccess to furcation areas than curette blades, espe-cially in deep furcation involvements. Such as-sumption is in accordance with the clinical andmicrobiological results reported by Leon & Vogel(48), who compared hand versus ultrasonic de-bridement in class I, II and III furcation involve-ments by assessing gingival crevicular fluid flowand the composition of the subgingival microflorausing dark-field microscopy. While in class I bothtreatments were equally effective, ultrasonic instru-ments proved more effective than hand scaling inreducing gingival fluid flow and bacterial pro-portions of spirochetes and other motile organismsin class II and III. This finding substantiates theresults reported by Matia et al. (56), who foundsignificantly more residual calculus in furcationsÆ2.3 mm wide after debridement with curettesthan with ultrasonic scalers.

Therefore, efforts have been made to constructspecially designed ultrasonic tips to improve accessi-bility to the innermost areas of the interradicularspace. In vitro studies have tested different sonic andultrasonic tips devised to gain access in the furcationarea, reporting satisfactory results in terms of arti-ficial calculus removal (43, 69, 75, 89). Longitudinalcontrolled clinical trials based on the use of thesenew instruments are needed to show their ultimateeffectiveness in vivo. However, improvement in cal-culus elimination in furcations with entrance dimen-sion of ∞2.4 mm has been also attained by utilizing

The conservative approach in the treatment of furcation lesions

a rotary diamond bur, thus circumventing the com-plications related to the presence of narrow furcationentrances (73, 74).

Methods and techniques ofconservative therapy

The long-term retrospective clinical studies reviewedabove (Table 2) employed a vast array of surgical andnonsurgical procedures. Unfortunately, as noted be-fore, no information is available on the applicationand outcome of the various techniques according tothe clinically diagnosed degree of involvement, pre-cluding the possibility of drawing conclusions aboutthe proficiency of each procedure in the differenttypes of destruction in furcations. The following sec-tions will discuss the effect of surgical and nonsurgi-cal procedures, chemotherapy and the more invasivetunnel preparation and root amputation.

Surgical and nonsurgical procedures

Few short-term studies are available for compari-sons of different forms of conservative techniques inthe treatment of selected furcation lesions. The ef-fectiveness of the various surgical and nonsurgicalapproaches employed has been studied in regard tothe residual amount of subgingival calculus (22, 56,73, 74, 103, 104), clinical parameters (38, 86, 99), andinterradicular bone density changes (10, 76). Otherstudies have used mechanical debridement as apositive control to determine whether any possibleadjunctive effect could be derived from the use oflocally delivered antibiotic therapy beyond that ofroot planing alone (61, 66, 68, 94).

A preliminary report by Wylam et al. (103) demon-strated the inadequacy of root planing with or with-out surgical access in grade II and III furcation areasof condemned teeth: residual plaque and calculuswere found in 89% and 95% of surgically and non-surgically treated molars. A later article by the sameauthors (104) reported that residual calculus de-posits covered on average 93.2% (range 79.2–100%)and 91.1% (range 77.4–100%) of furcal root surfacesafter closed and open instrumentation, respectively.

In contrast, Matia et al. (56) found significantlymore residual calculus after closed than open rootplaning in furcated molars with deep lesions (classII and III). No difference was observed between theuse of ultrasonic scalers and curettes in either group.However, when the data were stratified according to

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the dimension of the furcation entrance, open de-bridement with ultrasonics left significantly less cal-culus than curettes in entrances measuring Æ2.3mm. Similarly, Fleischer et al. (22) assessed the post-extraction amounts of residual calculus after a singlesession of scaling and root planing with or withoutsurgical access performed by operators with two dif-ferent skill levels. Among more experienced oper-ators, open root planing left more furcations free ofcalculus than closed debridement (68% versus 44%),but this difference did not reach statistical signifi-cance. When these procedures were performed bythe less experienced dentists, furcations occurredsignificantly more frequently with flap access thanfollowing closed debridement (43% versus 8%).Thus, the level of experience seems to play an ad-ditional role in furcation debridement, as the moreskilled periodontists achieved calculus-free furcationsurfaces more often than the less experienced oper-ators, regardless of the type of approach, although asignificant difference was noted only for thoselesions treated with closed root planing. No infor-mation was provided by Fleischer et al. (22) concern-ing the type and distribution of the furcal defects tobe treated. Parashis et al. (73, 74) evaluated in detailthe efficacy of calculus removal in class II and IIIfurcations achieved by scaling and root planing withor without surgical access. A third approach com-prised the use of a rotary diamond bur to removecalculus deposits in the furcation area after surgicalexposure. This combined treatment was best in re-moving calculus from furcations, especially in theflute area and when the furcation entrance meas-ured ∞2.4 mm. The studies by Matia et al. (56), Wy-lam et al. (103, 104), Fleischer et al. (22) and Parashiset al. (73, 74) were conducted on molars proposedfor extraction, characterized by the presence of se-vere bone destruction and heavy calculus deposits.Whether the results reported in these articles are ap-plicable to molars with less dramatic furcation in-volvements and calculus accretions has not yet beenestablished by other investigations.

It can be concluded that experienced operators re-move more calculus than those with less skill. In ad-dition, the open approach proves more efficacious atremoving calculus deposits from the furcation area,especially when combined with the use of a dia-mond bur.

However, the seemingly more beneficial resultsachieved with the combination of root planing andaccess surgery in terms of calculus removal demon-strated by Matia et al. (56), Parashis et al. (73, 74)and Fleischer et al. (22) are not accompanied by a

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corresponding superiority when dealing with clinicalparameters, as demonstrated by Kalkwarf et al. (38),Schroer et al. (86) and Wang et al. (99).

Kalkwarf et al. (38) evaluated the clinical responseof furcation regions to four types of periodontal ther-apy: supragingival scaling, root planing, modifiedWidman flap surgery or flap surgery with ostectomy.Flap surgery with concomitant bone resection wassignificantly better at reducing pocket depth thanthe other procedures, producing a mean decrease of1.65 mm. Conversely, it was the only type of treat-ment to produce a mean vertical attachment levelloss (0.36 mm) at the end of the 2-year observationperiod. Supragingival scaling, root planing andmodified Widman flap surgery demonstrated gain inprobing attachment of 0.32 mm, 0.44 mm and 0.4mm, respectively. All procedures, except root plan-ing, caused a loss of horizontal probing attachmentin furcations. The loss associated with osseoussurgery was significantly greater (0.51 mm) thanthose created by supragingival scaling (0.13 mm) andmodified Widman flap (0.14 mm). The best resultsfor attachment levels (vertical and horizontal) andpocket depths were recorded within the first yearpost-operatively. Despite the limited reduction ofpocket depths compared with the surgical pro-cedures, root planing proved more efficacious in pre-serving both vertical and horizontal attachmentlevels in furcations, and even produced gains insome sites. Interestingly, the implementation of oss-eous surgery brought about the extraction of a re-markable number (nΩ55) of furcated molars com-pared to other procedures. On the other hand, theremaining furcations, once treated with bone re-sective surgery, yielded a lower percentage of sitesdemonstrating clinically significant breakdown dur-ing the 2 years of maintenance. This may derive fromthe apical positioning of the gingival margin, where-by a facilitated cleansibility of the furcation entrancewas attained.

Schroer et al. (86) investigated attachment leveland probing depth change of closed versus open de-bridement in facial class II molar furcations. At 16months, both procedures had reduced pocket depthby 1.2–1.5 mm. A mean gain in attachment levelfrom baseline was observed after closed subgingivalscaling (0.6 mm), whereas treated furcations lostattachment (ª0.46 mm). However, this differencedid not reach statistical significance. Similarly, Wanget al. (99) reported no statistically significant differ-ence in attachment levels changes following eitherpocket elimination surgery, curettage or modifiedWidman flap.

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The more favorable clinical outcome in terms ofclinical attachment level observed by some investi-gators with closed debridement has also been corro-borated by studies aiming at assessing the quantitat-ive densitometric changes of alveolar bone withinfurcation areas either subjected to scaling and rootplaning or exposed to flap surgery (10, 76).

Payot et al. (76) treated class I or II furcation in-volvement with either subgingival curettage ormodified Widman flap or by furcation osteoplasty.All 3 procedures resulted in an initial loss of densityin the superficial layer of interradicular bone duringthe first 2 months following treatment. The loss wasthen followed by a statistically significant recovery,which became a net gain in density 1 year post-oper-atively only for sites treated by curettage. Likewise,bone loss was initially found in the profound layerafter the two surgical procedures. However, a sig-nificant net gain in density was detected at the endof the study, 1 year after therapy.

Equivalent results were reported by Bragger etal. (10). Loss of bone density occurred readily aftersurgical exposure, whereas a gain was recognizedfor furcation sites treated by closed root planing,denoting a statistically significant difference be-tween the two treatments. However, bone densitylevels were shown to be of comparable magnitudein surgical and nonsurgical sites 1 year post-oper-atively.

In conclusion, although scaling and root planingcombined with flap surgery is more effective at re-moving calculus, the clinical evaluations do not indi-cate a dramatic difference between surgical andnonsurgical treatments irrespective of the degree offurcation involvement. Rather, closed scaling androot planing proves more effective at preserving theexisting attachment level, together with producing amore expeditious bone remineralization, althoughthese phenomena are accompanied by a lesser re-duction in pocket depth. The equivalence in clinicalefficacy between closed and open procedures maybe attributed to the procedure, operator variables,compliance with professional recommendations, theinitial risk of the patient or, most likely, to a combi-nation of these factors.

A few studies are also available to compare theeffects of conservative treatment (open debride-ment) following surgical access used as a positivecontrol, with those of some selected regenerativeprocedures (39, 77, 105). Allografts such as poroushydroxyapatite (39) or tricalcium phosphate in com-bination with doxycycline (77) and collagen mem-branes (105) produced greater pocket reduction and

The conservative approach in the treatment of furcation lesions

defect fill than surgical debridement alone in class IIand III furcation defects.

Chemotherapy

The difficulties of performing adequate debridementin furcations by mechanical means has promptedexperimentation with chemotherapeutic agents inthese areas. Needleman & Watts (66) tested the ad-junctive effect of 1% metronidazole gel irrigationinto furcation areas with class II and III involve-ments during periodontal maintenance with subgin-gival scaling. Clinically, no further improvement wasseen for the furcations treated with metronidazole.Likewise, lack of adjunctive effect exerted by the me-tronidazole gel was reported for proportions ofspirochetes, motile rods and cocci observed withdark-field microscopy.

Nylund & Egelberg (68) evaluated the thera-peutic effects of subgingival irrigation with tetracy-cline as a supplement to mechanical debridementin furcations with class I, II and III involvements.The professional irrigation of 50 mg/ml tetracy-cline solution was performed every second weekfor 3 months. One-year evaluation of attachmentlevels and pocket depths showed similar clinicallynegligible (∞1 mm) variation in both tetracycline-and saline-irrigated furcations. It may be thereforeconcluded from these studies that sporadic, un-controlled local delivery of antibiotic substances isunlikely to exert any supplemental effect over thatproduced by subgingival mechanical treatment.Consequently, Minabe et al. (61) immobilized te-tracycline in a cross-linked collagen film to obtaina slow, sustained release of the drug. The film hasbeen subsequently used alone or in conjunctionwith root planing in furcation class II involvementsin a controlled randomized clinical trial. A dra-matic decrease in frequency of sites bleeding onprobing was noted in the group treated with acombination of tetracycline and mechanical de-bridement. The magnitude of reduction was sig-nificantly greater than that produced by either rootplaning or tetracycline film alone throughout thestudy period (8 weeks). Probing attachment levelsand pocket depths were similarly reduced by thethree treatment regimens. Likewise, comparabledecreases in the three groups were observed fortotal microbial counts and proportions of spiro-chetes, which dropped from pre-operative valuesof 10–17% to proportions of 2–3% at the end of ac-tive treatment (4 weeks). At 8 weeks, spirochetes inall three treatment groups were still far below the

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initial counts, although a slight return towardsbaseline values was noticeable. Very recent data byTonetti et al. (94) show that tetracycline-containingfibers exert a significant adjunctive pocket depthand bleeding reduction over that produced by scal-ing and root planing alone, although this finding isconfined only to the first 3 months following fiberinsertion. No difference between treatments couldbe observed, however, at the 6-month follow-upvisit, except for the significant greater number ofsites presenting with a pocket depth reduction ±2mm in the group receiving both scaling and rootplaning and fiber therapy. In summary, aside froma significant short-term anti-inflammatory effectmirrored by the increased reduction in bleedingupon probing, tetracycline in slow-delivery devicesdoes not seem to greatly enhance or prolong theeffectiveness of commonly used subgingival de-bridement in class II furcations.

Overall, the results from the studies above do notlend clear acceptance to the implementation of ad-junctive local drug therapy in furcation involve-ments, regardless of the degree of severity.

Tunnel procedure

The tunnel preparation of multi-rooted teeth is avery conservative approach in the treatment of classII and III furcation involvement (Fig. 4). The objec-tive of this treatment is to obtain the possibility ofcleaning the furcal area by the patient using an inter-dental toothbrush (29). The main advantage of thistechnique is the avoidance of prosthetic reconstruc-tion and, for mandibular molars, endodontic ther-apy. Unfortunately, tunnel preparation can be util-ized only when the furcation entrance dimension iswide enough and coronally located to allow for aneasy utilization of cleaning devices. These anatomi-cal restrictions limit use of this technique mainly tomandibular first molars, even if it can be im-plemented sometimes in maxillary molars (31). Inthis situation, however, one of the three roots mayhave to be resected to improve accessibility to thefurcation area.

Very few studies have investigated the possibilitiesof tunnel preparations. In a 5-year longitudinalstudy, Hamp et al. (29) found that four of seven teethtreated with this technique developed root caries,and three of them had been extracted during the ob-servation time.

Hellden et al. (31) evaluated in a retrospectivestudy the clinical outcome of tunnel preparations in102 patients (149 teeth) for a mean observation time

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Fig. 4. A. Pre-operative radiograph of a first mandibularmolar with a class 3 furcation involvement plus a distalinfrabony defect. B. Buccal mirror view of a tunnel prep-aration following a flap procedure. Note the suturesplaced in the interradicular space to keep the gingivaltissues as far apically as possible from the dome of thefurcation. C. One-year postoperative radiograph showinghealing of the distal infrabony defect and no caries in thefurcation area. D, E. Clinical pictures (mirror view) show-ing the healing of gingival tissues and the use of an inter-radicular cleaning aid (SuperflossA).

of 37.5 months (range 10 to 107 months). Sixty-threemaxillary and 35 mandibular first molars were themost treated teeth. Fluoride prophylaxis was per-formed after tunneling in the furcation areas. Tenteeth (7%) were extracted and 7 teeth (5%) were re-treated by hemisection. In 12 of these 17 teeth, theextractions and hemisections had been performedbecause of root caries. Among the remaining 132teeth, 23 (15%) showed initial or established caries.As approximately 75% of the treated teeth were stillcaries-free and in function at the end of the obser-vation period, the authors opined that tunnel prep-arations had a considerably better prognosis than

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previously reported by Hamp et al. (29) and couldtherefore be considered a valid treatment alternative.However, this is not an evidence-based conclusionbut rather only a proof of principle. To what extentthe procedure is better or worse than other forms ofconservative treatment cannot be said until a ran-domized controlled clinical trial is performed.

It could be argued that the shorter mean obser-vation time could account for the relatively lowerpercentage of new root carious lesions reported byHellden et al. (31) when comparing their results tothose of Hamp et al. (29). However, the formerauthors observed an increase root carious lesions

The conservative approach in the treatment of furcation lesions

development mostly during the initial 19 months ofthe follow-up period. This is in agreement with datareported by Ravald & Hamp (81) and Ravald et al.(82), who demonstrated that following periodontalsurgery the development of root caries mostly occurswithin 2 years after treatment. The results obtainedby Hellden et al. (31) in relation to root caries devel-opment could be due to the fluoride prophylaxisperformed by the patients in the furcations. In a re-cent study (51), the possibility of a tunnel prepara-tion procedure has been evaluated in 18 subjects,each having a molar with Glickman class II or III fur-cation involvement, who were followed for a meanobservation time of 5.8 years. The treated teeth werefive maxillary and 13 mandibular molars. At the endof the observation period, root caries was detectedin only three teeth (16.7%) confirming the results ob-tained by Hellden et al. (31). In addition, no differ-ence was found in attachment level and in radio-graphic bone evaluation in surgically tunneled man-dibular molars compared with adjacent sites treatedby osseous surgery.

Root amputation

Root amputation is a technique used in maxillarymolars by removing one of the three roots in orderto eliminate the furcation problem and to achievegood access for proper plaque control. As this tech-nique can be applied without gross changes in toothanatomy and without prosthetic reconstruction, itcan be considered a conservative approach to treatthe furcation involvement. This technique was intro-duced by Farrar in 1884 (21) and reintroduced byMessinger & Orban in 1954 (60). It has been advo-cated for use in combined periodontal-endodonticlesions (95) as well as bone loss related only to peri-odontitis (1). Only a few studies have followed theclinical course following root removal. Green fol-lowed 122 cases of molar hemisection or root ampu-tation for up to 25 years. In this group, 41 of 101maxillary molars that received root amputation wereremoved, most before 8 years (26). The cause of lossin almost every case was continuing breakdown ofperiodontal bone in spite of good oral hygiene andcareful plaque control on the part of these patients.Patients in a second study fared better, with 33 of 34maxillary molars surviving for 11 to 84 months afterroot amputation (41). Clinical experience has shownthat this procedure is often an interim step and thata large percentage of these teeth fail within a fewyears of root removal.

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Concluding remarks

O The studies reviewed here have shed new light onthe topic, transforming our therapeutic conceptsand prognostic paradigms regarding the manage-ment of furcation lesions.

O No data are to date available to infer that any ofthe various approaches advocated for treatmentof furcation lesions is to be preferred because itproduces better long-term results in terms offunctional survival. Likewise, studies comparingthe effects of different approaches within thesame subject are lacking.

O Retrospective long-term studies based on toothmortality demonstrated that teeth with initial fur-cation involvement can have a remarkable sur-vival rate following conservative treatments in pa-tients responding well to treatment.

O However, furcated teeth are lost in higher pro-portions as compared with single-rooted teeth orwith nonfurcated molars. The same trend hasbeen shown in studies based on clinical par-ameters, comparing the outcome of treatment be-tween teeth with furcation involvement with mo-lar flat surfaces and single-rooted teeth (36, 54, 67,99).

O These results could have been caused by the dif-ficulties in obtaining adequate debridement inteeth with furcation involvement. The peculiaranatomy of the area and the dimensions of theentrance diameter seems to be the reason for thepossible presence in furcations of residualamounts of subgingival plaque (53) and calculus(56, 73, 74). In this regard, more effective debride-ment was achieved in class II and III furcation in-volvement when surgical access was provided andultrasonic scalers or rotary diamond burs wereimplemented (48, 56, 73, 74).

O However, the clinical outcome of surgical andnonsurgical approaches is comparable in long-term as well as in short-term longitudinal studies.In some instances closed root planing has beenshown to better preserve clinical attachmentlevels (38, 86) and exert faster remineralization ofthe interradicular alveolar bone (10, 76).

O The above-mentioned studies show that the in-complete removal of subgingival debris in fur-cations using conservative treatments may not af-fect the clinical and biological response on an in-dividual site and patient basis. On the site level,the procedure utilized during the conservative ap-proach may have enhanced both self-performedand professionally performed plaque control. On

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the patient level, the favorable response to treat-ment of most subjects observed in the long-termretrospective studies (well-maintained groups) to-gether with the long functional survival rate ofmost furcated molars may be related to adequateplaque control and low susceptibility to disease inthe majority of periodontal patients, thus explain-ing the long-standing acceptable results of treat-ment. On the other hand, the specific proceduresemployed and the severity of furcation involve-ments were not taken into account in these sur-veys. This made it impossible to relate the type oftreatment applied to the degree of involvement inthe evaluation of the outcome of therapy.

O A very limited number of studies have been per-formed on tunnel preparation, with differing re-sults. However, the study by Hellden et al. (31),who enrolled a considerable number of patients,demonstrated promising results, although themean observation time was limited. Moreover,long-term prospective and controlled studies onthis technique are needed to corroborate thesefindings.

O Very little information is available on root ampu-tations and odontoplasty. However, root ampu-tation has not been extensively used in clinicallong-term studies. Therefore, caution must be ex-ercised when interpreting the limited publisheddata.

O The use of drugs does not seem to add long-termadvantages to the benefits obtainable by rootplaning alone. However, the encouraging short-term reduction in bleeding on probing and pocketdepth observed by Tonetti et al. (94) indicates thathigh concentrations of an antimicrobial drugcombined with conventional treatment have thepotential of improving the clinical response at fur-cation sites, during supportive periodontal care.

O Even if the management of furcation involvementteeth with a conservative approach does not yieldthe same satisfactory results as with single-rootedteeth or molar flat surfaces, the alternative treat-ments based on resection or regeneration are notmuch more promising. Studies on regenerationhave shown the unpredictability of complete clo-sure of furcation involvement (16). Some reportson root resection or root separation have shownremarkably low failure rates (4–8%) (2, 5, 15), al-though other long-term studies demonstrateddefinitely less favorable results with such therapy,tooth mortality ranging after 10 years between 32–38% (12, 26, 47), while Langer et al. (47) reporteda total failure rate of 51% after 20 years of follow-

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up. However, the well-maintained groups, repre-senting the vast majority of the patients in long-term retrospective studies based on a conservativeapproach, have shown, in a much longer obser-vation period, a tooth mortality of furcation in-volvement molars ranging from 16.7% to 27.7%(Table 3). These rates are much lower than thosereported by the majority of the studies based onroot separation or resection for a considerablyshorter time. These findings lead to the con-clusion that the conservative approach for fur-cation involvement teeth can be performed in themajority of patients with the expectation of a highlong-term survival rate for the patients demon-strating an overall satisfactory response to con-ventional periodontal treatment (Fig. 5).

Establishing prognosis

The prognosis of furcated teeth treated by conserva-tive approach lends itself to a moderate degree ofoptimism, bearing in mind, however, that the pres-ence of interradicular alveolar bone destruction maystill be considered a local risk factor for tooth loss(58, 59) (Table 4).

Other local factors may accelerate the rate of dis-ease progression, thus increasing the risk for exfoli-ation of furcated teeth: restorations (98) and smok-ing habits (64) have been shown to be positively cor-related with the presence of furcation involvement,while mobile furcated molars are at greater risk forloss of attachment in the furcation area (99).

A few risk factors have been identified in theliterature to play a role in the fate of treated furcatedteeth. Advanced periodontal disease (7) and smokinghave generally been shown to influence the outcomeof therapy in conservative and resective treatments(7, 37). Such factors must be kept in mind by theclinician in that their suppression or reduction maygreatly improve the prognosis of furcated teeth.Moreover, genetic testing for inflammatory modifiers(44) may be helpful to guide treatment planning andprognosis for the different approaches according tothe individual response to treatment.

Once the identified risk factors are ameliorated oreliminated, the clinician may consider the conserva-tive approach as a first option. Frequent monitoringduring supportive periodontal treatment is import-ant to ensure the stability of the periodontal struc-tures within furcations. If recurrence appears, ad-ditional care, including new instrumentation, local

The conservative approach in the treatment of furcation lesions

Fig. 5. A, B. Clinical pictures taken in 1980 from a patientwith generalized periodontal destruction. The patient wastreated by scaling and root planing under local anesthesiaand refused surgical treatment. C, D. Clinical pictures ofthe same patient 17 years later. Note the good plaque con-trol and the generalized recession of the gingival margin.The patient had been subjected to 3-month supportiveperiodontal care since initial scaling and root planing.E. Initial radiograph of maxillary right molars showingfurcation involvement in the first molar (the tooth wasvital). F. Radiograph of the same area as in Fig. 5e showingthe remineralization of the interradicular osseous lesion17 years later. The wisdom tooth was extracted. G. Clinicalappearance of the area in 1997.

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Fig. 6. A. A radiography of the mandibular right posteriorsextant taken in 1981. B. The patient (seen here in 1987)continued to loose bone in spite of the fact that he im-proved his compliance with home care and professionalcleanings and had several rounds of closed and open scal-ing and root planing. C. The teeth were removed in 1997and dental implants placed. The patient was found to begenotype-positive for the IL-1 gene.

drug therapy and root separation, may be appro-priate.

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