Jan Lindhe. Clinical Periodontology

Подождите немного. Документ загружается.

CHAPTER

Treatment of

Furcation-Involved Teeth

GIANFRANCO CARNEVALE, ROBERTO PONTORIERO AND JAN LINDHE

Therapy

Scaling and root planing

Furcation plasty

Tunnel preparation

Root separation and resection (RSR)

Regeneration of furcation defects

Extraction

Prognosis

Terminology

Anatomy

Diagnosis

Differential diagnosis

Detailed knowledge of the morphology of the multi-

rooted teeth and their position in the dental arch is a

fundamental prerequisite for a proper understanding

of problems which may occur when such teeth be-

come involved in destructive periodontal disease. The

first part of this chapter therefore includes a brief

description of some important anatomic features of

the root complexes and related structures of premolars

and molars.

TERMINOLOGY

Root complex

is the portion of a tooth that is located

apical of the cemento-enamel junction (CEJ), i.e. the

portion that normally is covered with a root cemen-

turn. The root complex may be divided into two parts:

the

root trunk

and the

root cone(s)

(Fig. 29-1).

The

root trunk

represents the

undivided region

of the

root. The height of the root trunk is defined as the

distance between the CEJ and the separation line (fur

cation) between two root cones (roots). Depending on

the position of the separation line the height of the root

trunk may vary from one surface to the next in one

given molar or premolar.

The

root cone is

included in the

divided region

of the

root complex. The root cone (root) may vary in size

and position and may at certain levels be connected to

or separated from other root cones. Two or more root

Fig. 29-1. Root complex of a maxillary molar. The root

complex is separated into one undivided region: the

root trunk, and one divided region: the (3) root cones.

cones make up the

furcated region

of the root complex

(Fig. 29-2a).

The

furcation

is the area located between individual

root cones.

Furcation entrance:

the transitional area between the

undivided and the divided part of the root (Fig. 29-

2a,

b).

Furcation fornix:

the roof of the furcation (Fig. 29-2b).

Degree of separation:

the angle of separation between

two roots (cones) (Fig. 29-3a).

Divergence is

the distance between two roots; this

distance normally increases in apical direction (Fig.

29-3a).

706 • CHAPTER 29

Fig. 29-2. Apical-occlusal view of a maxillary molar where the three root cones make up the furcated region and the

three furcation entrances (a). A buccal view of the furcation entrance and of its roof (b).

Fig. 29-3. Photographs illustrating the angle (degree) of separation and the divergence between the mesiobuccal

and the palatal roots of a maxillary molar (a). The coefficient of separation (A/B) of the illustrated mandibular mo

lar is 0.8 (A = 8 mm; B = 10 mm).

Coefficient of separation:

the length of the root cones

in relation to the length of the root complex (Fig.

29-3b)

Fusion between divergent root cones may occur.

The fusion may be complete or incomplete. In the case

of an incomplete fusion, the root cones may be fused

in the area close to the CEJ but separated in a more

apical region of the root complex.

ANATOMY

Maxillary molars

As a general rule the maxillary first molar, in all re-

spects — crown and individual roots — is larger than the

second molar, which in turn is larger than the third

molar.

The first and second molars most often have three

roots; one mesiobuccal, one distobuccal and one pala-

tal. The mesiobuccal root is normally vertically posi-

tioned while the distobuccal and the palatal roots are

inclined. The distobuccal root projects distally and the

palatal root projects in palatal direction (Fig. 29-4a-c).

The cross-sections of the distobuccal and the palatal

roots are generally circular. The palatal root is gener

ally wider in mesiodistal than in buccopalatal direc-

tion. The distal surface of the mesiobuccal root has a

concavity which is about 0.3 mm deep (Bower

1979a,

b). This concavity gives the cross-section of the

mesiobuccal root an "hour-glass" configuration (Fig.

29-5).

The three furcation entrances of the maxillary first

and second molars vary in width and are positioned at

varying distances apical of the CEJ. As a rule, the

first

molar has a shorter root trunk than the second

molar.

In the first molar the mesial furcation entrance is

located about 3 mm from the CEJ, while the buccal

3.5 mm and the distal entrance about 5 mm apical

CEJ (Abrams & Trachtenberg 1974, Rosenberg

1988).

This implies that the furcation fornix is inclined;

in the

mesiodistal plane the fornix is comparatively

close to

CEJ at the mesial but closer to apex at the distal

surface.

The buccal furcation entrance is narrower

than its

distal and mesial counterparts.

The degree of separation between the roots and

their

divergence decreases from the first to the second,

and

from the second to the third maxillary molar.

The mesiobuccal root of the first molar is frequently

located more buccally in the arch than the distobuccal

root. If the buccal bone plate is thin, the mesiobuccal

root frequently projects through the outer surface of

TREATMENT OF FURCATION-INVOLVED TEETH •

707

Fig. 29-4. Furcation entrances (a, mesial; b, buccal; c, distal) and the position of the roots of a maxillary first molar.

Fig. 29-5. Root-shape of a maxillary first molar in a

horizontal cut at the level of the coronal third of the

cones. Note the circular shape of the palatal root in

comparison with the mesiodistally compressed shape

of the mesiobuccal root, which also exhibits a concav

ity in the distal aspect.

the alveolar bone and bone fenestrations and/or de-

hiscences may occur.

Maxillary premolars

In about 40% of cases the maxillary first premolars

have two root cones — one buccal and one palatal, and

hence a mesiodistal furcation. A concavity (about 0.5

mm deep) is often present in the furcation aspect of

the

buccal root. The furcation is in many cases located

the middle or in the apical third of the root complex (

Fig. 29-6). The mean distance between CEJ and the

furcation entrance is about 8 mm. The width of the

furcation entrance is about 0.7 mm.

Mandibular molars

The mandibular first molar is larger than the second

molar, which in turn is larger than the third molar. In

the first and second molars the root complex almost

always includes two root cones, one mesial and one

distal. The mesial root is larger than the distal. The

mesial root has a position which is mainly vertical

while the distal root projects distally. The mesial root

wider in the buccolingual direction and has a larger

cross-section area than the distal root. The cross-sec-

tion of distal root is circular while the mesial root has

an "hour-glass" shape. In addition, on the distal sur-

face of the mesial root, furrows and concavities often

occur (Fig. 29-7). The distal concavity of the mesial

root

is more pronounced than that of the distal root

(Bower

1979a,b, Svardstrom & Wennstrom 1988).

The root trunk of the first molar is often shorter than

the trunk of the second molar. The furcation entrances

of the mandibular first molar, similar to those of the

maxillary first molar, are located at different distances

from the CEJ. Thus, the lingual entrance is frequently

found more apical of CEJ (> 4 mm) than the buccal

708 •

CHAPTER

Fig. 29-6. A maxillary first premolar with the furcation

located in the apical third of the root complex.

Fig. 29-7. "Hour-glass" shape of the mesial root — with

concavity in the distal aspect — and the circular shape

of the distal root (horizontal section at the level of the

coronal third of the cones).

Fig. 29-8. From left to right, differences in degree of

separation and in divergence between the root cones

from the first to the mandibular third molar.

entrance (> 3 mm). Thus, the furcation fornix is in-

clined in the buccolingual direction. The buccal furca-

tion entrance is often < 0.75 mm wide while the lingual

entrance is > 0.75 mm in most cases (Bower 1979a,b).

The degree of separation and divergence between

the

roots decreases from the first to the third molar

(Fig. 29-

8).

It should also be observed that the buccal bone plate

is thinner outside the roots of the first than of the

second molar. Bone fenestrations and dehiscences are,

as a consequence, more frequent in the first than in the

second molar region.

Other teeth

Furcations may be present also in teeth which nor-

mally have only one root. In fact, two-rooted incisors

(Fig. 29-9a), canines (Fig. 29-9b) and mandibular pre-

molars may exist. Occasionally three-rooted maxillary

premolars (Fig. 29-10a) and three-rooted mandibular

molars can be found (Fig. 29-10b).

DIAGNOSIS

The presence of furcation-involved teeth in a peri-

odontal patient will influence the treatment plan (see

Chapter 19). The selection of procedures to be used in

the treatment of periodontal disease at multirooted

teeth

can first be made when the presence and depth

furcation lesions have been assessed. In this exami-

nation traditional measures of periodontal disease are

used (see Chapter 18) but special attention is paid to

TREATMENT OF FURCATION-INVOLVED TEETH •

709

Fig. 29-9. Radiographs illustrating

morphologic variations repre-

sented by two-rooted (a) maxil-

lary lateral incisor and (b)

mandibular canine.

Fig. 29-10. Anatomic variation rep

resented in a radiograph of a

three-rooted mandibular first pre

molar (a). Clinical photograph il-

lustrating, during surgery, the

separation — before extraction — of

an "abnorma

second mesial root

of a mandibular molar (b).

findings from clinical

probing

and analysis of

radio-

graphs

from the premolar-molar regions.

The classification description of the involved furca-

tion is based on the amount of periodontal tissue

destruction that has occurred in the interradicular

area, i.e. degree of "horizontal root exposure" or at-

tachment loss that exists within the root complex.

Hamp et al. (1975) has suggested the following classi-

fication of the involved furcation:

•

Degree I: Horizontal loss of periodontal support not

exceeding

of the width of the tooth (Fig. 29-11a).

•

Degree II: Horizontal loss of periodontal support

exceeding

of the width of the tooth, but not

encompassing the total width of the furcation area

(Fig. 29-11b).

•

Degree III: Horizontal "through and through" de-

struction of the periodontal tissues in the furcation

area (Fig. 29-11c).

It is important to understand that each furcation en-

trance must be examined and each entrance must be

classified according to the above criteria.

Probing

The buccal furcation entrance of the

maxillary molars

and the buccal and lingual furcation entrances of the

mandibular molars

are normally accessible for exami-

nation using a curved graduated periodontal probe

(

Fig. 29-12a,b), an explorer or a small curette. The

examination of approximal furcations is more diffi-

cult, in particular when neighboring teeth are present.

Large contact areas between the teeth further impair

access to approximal furcation entrances.

In maxillary molars the mesial furcation entrance is

located much closer to the palatal than to the buccal

tooth surface. Thus, the mesial furcation should be

probed from the palatal aspect of the tooth (Fig. 29-13).

The distal furcation entrance of

a maxillary molar is

generally located midway between the buccal and

palatal surfaces and, as a consequence, this furcation

710 • CHAPTER

Fig. 29-11. Different degrees of furcation involvement in relation to the probe (penetration/superimposition) in the

interradicular space of a mandibular molar. (a) degree I; (b) degree II; (c) degree III.

Fig. 29-12. Easily accessible vestibular furcation entrances for probing of a (a) maxillary molar and (b) mandibular

molar.

Fig. 29-13. Common access for probing of a mesial fur-

cation entrance of a maxillary molar. The mesial furca-

tion entrance is generally located at the palatal aspect

of the tooth, while the distal entrance is located mid-

way between the buccal and the palatal surface.

TREATMENT

FURCATION-INVOLVED

TEETH • 711

Fig. 29-14. Radiograph showing the location of the in

terdental bone level in relation to the furcation en-

trances of the maxillary first and second molar.

Fig. 29-15. Radiographs of the right maxillary molar region where, with a normal bisecting projection, the

furcation

defect of the first molar is not evident (a). It is, however, easily identified in a bitewing radiograph (b).

could be probed from either the buccal or the palatal

aspect of the tooth.

maxillary premolars

the root anatomy often varies

considerably. The roots may also harbor irregularities

such as longitudinal furrows, invaginations or true

furcations, which may open at varying distances from

the CEJ. Due to the above variations and due to the

limited access, the clinical assessment of a furcation

involvement in maxillary premolars is often difficult.

In some patients, a furcation involvement may, in such

teeth, first be identified after the elevation of a soft

tissue flap.

Radiographs

Radiographs must always be obtained to confirm

findings made during probing of a furcation-involved

tooth. The radiographic examination should include

both paralleling "periapical" and vertical "bite-wing"

radiographs. In the radiographs the location of the

interdental bone as well as the bone level within the

root complex should be examined (Fig. 29-14). Situ-

ations may occur when findings from clinical probing

and from the radiographs are inconsistent. Thus, the

localized but extensive attachment loss which maybe

detected within the root complex of a maxillary molar

with the use of a probe, will not always appear in the

radiograph. This may be due to the superimposition

in the radiograph of the palatal root and of remaining

bone structures (Fig. 29-15a). In such a case, additional

radiographs with different angles of orientation of the

central beam should be used to identify bone loss

within the root complex (Fig. 29-15b).

DIFFERENTIAL DIAGNOSIS

A lesion in the interradicular space of a multirooted

tooth may be associated with problems originating

from the root canal or be the result of occlusal over-

load. The treatment of a furcation-involved tooth,

therefore, should not be initiated until a proper differ

ential diagnosis of the lesion has been made.

Pulpal pathosis

may sometimes cause a lesion in the

periodontal tissues of the furcation (see Chapter 14).

The radiographic appearance of such a defect may

712 • CHAPTER 29

Fig. 29-16. Radiographs demonstrating a destruction of interradicular hone and the presence of periapical

defects

at the mesial and distal roots of a maxillary first molar (a). Radiographic appearance of complete healing

of the interradicular and periapical lesions after endodontic treatment (b).

have some features in common with a plaque-associ-

ated furcation lesion. In order to differentiate between

the two lesions the vitality of the affected tooth must

always

be tested. If the tooth is vital, a plaque-associ-

ated lesion should be suspected. If the tooth is non-vi

tal, the furcation involvement may have an endodon-

tic origin. In such a case, proper endodontic

treatment

must

always

precede periodontal therapy.

In fact, en

dodontic therapy may resolve the

inflammatory le

sion, soft and hard tissue healing

occur and the furca

tion defect disappear (Fig. 29-16a,

b). If signs of healing

of a furcation defect fail to

appear within 2 months following endodontic

treatment, the furcation in

volvement is probably

associated with marginal peri

odontitis.

Trauma from occlusion

Forces elicited by occlusal interferences, e.g. bruxers

and clenchers (see Chapters 15, 30), may cause inflam

mation and tissue destruction or adaptation within

the interradicular area of a multirooted tooth. In such

a tooth a radiolucency may be seen in the radiograph

of the root complex. The tooth may exhibit increased

mobility Probing, however, fails to detect an involve-

ment of the furcation. In this particular situation, oc

clusal adjustment must always precede periodontal

therapy. If the defects seen within the root complex are

of "occlusal" origin, the tooth will become stabilized

and the defects disappear within weeks following

correction of the occlusal overload (Fig. 29-17a,b).

THERAPY

Treatment of a defect in the furcation region of a

multi-rooted tooth is intended to meet two objectives:

the elimination of the microbial plaque from the

exposed surfaces of the root complex

the establishment of an anatomy of the affected

surfaces that facilitates proper self-performed

plaque control.

Different methods of therapy are recommended:

Furcation involvement degree I

Recommended therapy: Scaling and root planing.

Furcation plasty.

Furcation involvement degree II

Recommended therapy: Furcation plasty. Tunnel

preparation. Root resection. Tooth extraction. Guided

tissue regeneration at mandibular molars.

Furcation involvement degree III

Recommended therapy: Tunnel preparation. Root re-

section. Tooth extraction.

Scaling and root planing

Scaling and planing of the root surfaces in the furca-

tion entrance of a degree I involvement in most situ-

ations result in the resolution of the inflammatory

lesion in the gingiva. Healing will re-establish a nor-

mal gingival anatomy with the soft tissue properly

adapted to the hard tissue walls of the furcation en-

trance (Fig. 29-18a,b).

Furcation plasty

Furcation plasty (Fig 29-19a-f) is a resective treatment

modality which should lead to the elimination of the

interradicular defect. Tooth substance is removed

(

odontoplasty) and the alveolar bone crest is remod-

eled (osteoplasty) at the level of the furcation entrance.

TREATMENT OF FURCATION-INVOLVED TEETH • 713

Fig. 29-17. Radiographic appearance of a defect in the furcation area caused by occlusal overload (a). After occlusal

adjustment the interradicular defect spontaneously healed, as documented 6 months after therapy in a

radiograph

(courtesy of M. Cattabriga).

Fig. 29-18. Resolution of inflammatory lesions in the gingiva achieved by scaling, root planing and the re-establish

ment of a correct tissue morphology in the interradicular area of degree I furcation involved mandibular molars.

(

a) Before therapy, (b) 6 months after therapy

Furcation plasty is used mainly at buccal and lingual

furcations. At approximal surfaces access is often too

limited for this treatment.

Furcation plasty involves the following proce

dures:

•

The dissection and reflection of a soft tissue flap to

obtain access to the interradicular area and the sur

rounding bone structures.

•

The removal of the inflammatory soft tissue from

the

furcation area followed by careful scaling and

root

planing of the exposed root surfaces.

•

The removal of crown and root substance in the

furcation area (odontoplasty) to eliminate or reduce

the horizontal component of the defect and to widen

the furcation entrance.

•

The recontouring of the alveolar bone crest in order

to reduce the buccal-lingual dimension of a bone

defect in the furcation area.

•

The positioning and the suturing of the mucosal

flaps at the level of the alveolar crest in order to

cover the furcation entrance with soft tissue. Fol-

lowing healing a "papilla"-like tissue should close

the

entrance of the furcation.

Care must be exercised when odontoplasty is per-

formed on vital teeth. Excessive removal of tooth

structure will enhance the risk for increased root sen-

sitivity.

Tunnel preparation

Tunnel preparation is a technique used to treat deep

degree II and degree III furcation defects in mandibu-

lar molars. This type of resective therapy can be of-

fered at mandibular molars which have a short root

trunk, a wide separation angle and long divergence

between the mesial and distal root. The procedure

includes the surgical exposure and management of the

entire furcation area of the affected molar.

Following the reflection of buccal and lingual mu-

cosal flaps, the granulation tissue in the defect is re-

moved and the root surfaces are scaled and planed.

The furcation area is widened by the removal of some

of the interradicular bone. The alveolar bone crest is

recontoured and to obtain a flat outline of the bone,

some of the interdental bone, mesial and distal to the

tooth in the region, is also removed. Following hard

tissue resection enough space has been established in

the furcation region to allow access for cleaning de-

vices to be used during self-performed plaque control

714 •

CHAPTER

Fig. 29-19. Furcation plasty performed at the buccal aspect of a mandibular molar. (a) Initial degree II furcation in

volvement. (b) After flap elevation, removal of the granulation tissue and scaling of the exposed root surfaces. (c)

After odontoplasty. (d) After osteoplasty. (e) Apical position of the flap managed by periosteal sutures. (f) Healing

resulting in the elimination of the furcation defect and in the establishment of a proper soft tissue morphology.

measures (Fig. 29-20a,b). The flaps are apically posi-

tioned to the surgically established interradicular and

interproximal bone level.

During maintenance the exposed root surfaces

should be treated by topical application of chlor-

hexidine digluconate and fluoride varnish. This sur-

gical procedure should be used with caution, because

there is a pronounced risk for root sensitivity and for

carious lesions developing on the denuded root sur-

faces within artificially prepared tunnels (Hamp et al.

1975).

Root separation and resection (RSR)

Root separation

involves the sectioning of the root com-

plex and the maintenance of all roots.

Root resection

involves the sectioning and the removal of one or two

roots of a multirooted tooth.

RSR is frequently used in cases of deep degree II

and degree III furcation involved molars.

Before RSR is performed the following factors must

be considered:

The length of the root trunk

In a patient with progressive periodontal disease a

tooth with

short

root trunk may have an early in-

volvement of the furcation (Larato 1975, Gher & Vern-