Jan Lindhe. Clinical Periodontology

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REHABILITATION BY MEANS OF IMPLANTS: CASE REPORTS • 997

Fig. 42-24.

Case:

L.T

PLI: 100%

BoP: 100%

Initial Examination: 751009

Periodontal charting

Tooth

Pocket depth

Furcation

involvement

Tooth

mobility

M B

1.7

16 8 5 6

15 5 6 6

13 10 8 10

11 8 6 7 1

21 8 8 10 2

23 6 6 9

27 10 8 8

mll,dII

2'8

Fig. 42-25.

Tooth

Pocket depth

M B

Furcation

involvement

Tooth

mobility

54'/

43 4 6 1

4'1

4 2

33 6 6 6

35 10 6 8

10 10 4

III

PATIENT 5

IMPLANTS USED TO SOLVE

RESTORATIVE PROBLEMS

OCCURRING DURING

MAINTENANCE THERAPY

The periodontal condition of this 48-year-old man in

1975 is illustrated by the radiographs (Fig. 42-24), the

measurements included in the periodontal chart (Fig.

42-25), and the clinical photograph (Fig. 42-26) from

the examination of October 10. An analysis of the data

from this examination disclosed a patient with ad-

vanced periodontal disease which at most teeth had

progressed to a level where only the apical third, or

less, of the roots had remaining periodontal tissue

support.

Fig. 42-26.

Treatment planning

Following careful planning of the treatment it was

decided that (1) initially no teeth had to be removed;

(

2) several teeth were questionable, i.e. 13, 11, 21, 23,

27 as well as 35 and 37; (3) teeth 16, 15 as well as 33,

998 • CHAPTER 42

Fig. 42-27a-c.

Fig. 42-28a-c.

REHABILITATION BY MEANS OF IMPLANTS: CASE REPORTS •

999

Fig. 42-29.

Fig. 42-30.

32, 43 could be maintained; (4) the patient should after

the completion of periodontal therapy be restored

with fixed cross-arch splints in the maxilla and man

dible.

Treatment (1)

Following case presentation and oral hygiene instruc

tion, temporary bridges were prepared for both the

maxilla and mandible. The maxillary bridge extended

from 16 to 24, and the mandibular bridge from 44 to

34 (Figs. 42-27a-c). Teeth 27, 35 and 37 were subjected

to endodontic therapy.

Mucoperiosteal flaps were elevated, the root sur-

faces were carefully debrided and planed. Root sepa

ration and hemisection was performed at 27 and 37.

After 6 months of healing, permanent restorations

were inserted (Figs. 42-28a-c and 42-29). Note that the

mandibular bridge was designed with two cantilever

units in the 4th quadrant (for details regarding the

design of the occlusion and the cantilever extension

see Chapter 41).

The patient was enrolled in a maintenance care

program which included recall visits (1) once every 3

months to the dental hygienist and (2) once a year to

the dentist.

During a 9-year interval no sign of recurrent peri

odontal disease was observed.

In 1984, an acute marginal abscess originating from

a periapical lesion occurred at tooth 43. Endodontic

Fig. 42-31.

therapy was performed, the lesion was resolved, a

post was placed in 43, and the most distal cantilever

unit (45) was removed. Two years later, in 1986, the

root of tooth 43 exhibited a long fracture and was

extracted (Fig. 42-30). The bridge in the mandible had

to be separated mesial of tooth 32. The abutments

available in the mandible were 32, 33, 35 and the distal

root of 37.

Two treatment alternatives were possible at this

interval:

Removable partial denture

Implant-supported fixed bridge in quadrant 4.

1000 • CHAPTER

Fig.

42-32.

Fig.

42-33.

Fig.

42-34.

Fig.

42-35.

Treatment (2)

Three fixtures a.m. Branemark (Branemark System

Nobel Biocare) were placed in the area between the

foramen mentale in quadrant 4 and the lateral incisor

(32) in quadrant 3. Four months later a fixed bridge

was connected to the implants (Fig. 42-31). This resto

ration extended from 45 to 31.

The installation of the implant-retained bridge ap

parently resulted in an altered occlusion and a force

distribution (and magnitude) which — despite re-

peated occlusal adjustment — caused an increasing

mobility (arrows) of the left segment of the maxillary

splint. This condition is illustrated in a radiograph in

Fig. 42-32, which was obtained in 1992.

Treatment (3)

At this time interval teeth 11, 21 and the palatal root

of 27 could no longer be maintained and were ex-

tracted. Only teeth 16, 15 and 13 could be maintained

in the maxilla.

Implants were placed in positions 14, 12, 21 23 and

25 (Fig. 42-33). Following 6 months of healing, abut

ment connection was performed. A two-unit bridge

was placed on 16 and 15. This bridge was designed

with a mesial sliding attachment (Fig. 42-34). Tooth 13

was fitted with an inner crown (Fig. 42-34). An im-

plant-supported bridge extending from position 14 to

26 (including 13 as a telescoping unit) was inserted

and connected to the bridge on 16/15 via the attach

ment (Figs. 42-35 and 42-36). Figs. 42-37 and 42-38a-c

illustrate the clinical and radiographical appearance 3

years after treatment (3).

Concluding remarks

This case demonstrates that during the course of a

successful" maintenance care program unexpected

and unanticipated problems may occur. This particu

lar patient honored all recall visits, and the dentist and

dental hygienist consistently carried out proper sup

portive care measures. The vitality of the pulp of tooth

43 was lost — reason unknown — the tooth was root

filled through the restoration and a post placed. This

REHABILITATION BY MEANS OF IMPLANTS: CASE REPORTS • 1001

Fig. 42-36.

Fig. 42-37.

Fig. 42-38a-c.

obviously compromised the support and retention for distal endabutment (43). Implant treatment was used

the bridge in the mandible and a situation developed as an alternative to a removable partial denture. An

which eventually resulted in a long fracture of this implant-supported bridge - ankylotic - now occluded

1002 • CHAPTER 42

Fig. 42-39.

Fig. 42-40.

against a tooth-supported maxillary splint with com

promised abutments. The forces elicited during occlu

sion were difficult to control and eventually jeopard-

ized the stability of the maxillary splint.

PATIENT 6

IMPLANTS USED TO SOLVE

PROBLEMS ASSOCIATED WITH

ACCIDENTAL ROOT FRACTURES

IMPORTANT ABUTMENT

TEETH

Initial examination

Following proper periodontal treatment of this 57-

year-old woman in 1976, only four teeth could be

maintained in the maxilla, i.e. 13, 11, 22 and 23. These

two teeth were used as abutments for a fixed cross-

arch bridge extending from 15 to 25. In the mandible

the teeth 43, 42, 32 and 33 were maintained and used

as abutments for a fixed bridge extending from 45 to

35. In both the maxillary and mandibular restorations,

two cantilever units were placed on each side of the

midline. The condition, 3 years following initial ther

apy (i.e. in 1979), is illustrated by the radiographs

shown in Fig. 42-39.

Following this treatment the patient was placed in

a maintenance care program which called for appoint

ments with the dental hygienist once every 3

months

and with the dentist once a year.

After 10 years of supportive dental care, the reten

tion of the bridge at tooth 13 was lost due to a compro

mised cement lock. The bridge was removed. A new

post was placed in 13 and a new bridge inserted. This

bridge had an extension identical to that of the original

one.

After another 2 years (i.e. 1988) a marginal abscess

occurred at the distal/palatal aspect of 13. Note in Fig.

42-40 the gutta-percha point that was inserted in the

lesion. After flap elevation, a fracture could be identi

fied in the root of 13; the tooth was subsequently

removed.

Treatment planning and treatment

At this stage, 11, 22 and 23 were available as abut-

ments. The bridge was separated distal of tooth 11 and

four fixtures (Branemark

System, Nobel Biocare)

were inserted in positions 16, 15, 13 and 12. After 6

months of healing, abutment connection was per-

formed, and a six-unit implant-supported bridge, ex

tending from position 17 to position 12, was fabricated

and attached to the implant pillars (Figs. 42-41 and

42-42).

Following this treatment the patient was again

placed in the maintenance care program.

Figs. 42-43 and 42-44a,b demonstrate the clinical

and radiographic appearance of the resonstruction 20

years following initial therapy.

Concluding remarks

This case illustrates how implants can be used to solve

difficult problems in patients who during a mainte-

nance care program experience unexpected tooth loss.

REHABILITATION BY MEANS OF IMPLANTS: CASE REPORTS • 1003

Fig. 42-42.

Fig. 42-44a,b.

Fig. 42-41.

Fig. 42-43.

CHAPTER 43

Implants Used for Anchorage

in Orthodontic Therapy

HEINER WEHRBEIN

Implants for orthodontic anchorage

Orthodontic-prosthetic implant anchorage

(OPIA)

Orthodontic implant anchorage (OIA)

Direct and indirect orthodontic implant

anchorage

Palatal orthodontic implant anchors

Anchorage is a fundamental problem in the treatment

of dental and skeletal dysgnathia. The loading of the

anchorage unit is based on conditions of static equi

librium (action = reaction) as defined by Newton as

long ago as 1687 (cf. Diedrich 1993).

If teeth are used for anchorage purposes, their reac

tive load with respect to quantity, direction, type and

duration is yielded by the forces and moments applied

through the orthodontic biomechanics for the active

tooth movements. This problem has to be taken into

account in any anchorage planning. If the periodontal

anchorage potential is inadequate with respect to the

treatment goal, additional intraoral and/or extraoral

anchorage aids may be needed if negative side effects

are to be avoided (Diedrich 1993).

Additional anchorage aids such as headgear and

intermaxillary elastics are, however, characterized by

potential disadvantages: visibility, compliance de-

pendence, and the risk of undesirable side effects.

Intraoral anchorage aids such as Class II elastics are

not visible but are also compliance-dependent and

may be accompanied by certain side effects: tipping of

the occlusal plane, protrusion of mandibular incisors,

and extrusion of teeth.

The aim of this chapter is to demonstrate and dis

cuss how implants as positionally stable, intraoral

(

invisible) and compliance-independent anchorage

units may be integrated into orthodontic treatment

tasks, with some of the disadvantages listed above

being avoided.

IMPLANTS FOR ORTHODONTIC

ANCHORAGE

Case reports and prospective clinical studies as well

as experiments on animals have shown that osseoin

tegrated implants remain positionally stable under

orthodontic and even orthopedic loading conditions (

e.g. Linkow 1970, Turley et al. 1980, 1988, Roberts et

al. 1984, 1990a,b, Odman et al. 1988, 1994, Shapiro &

Kokich 1988, Van Roeckel 1989, Haanaes et al. 1991,

Wehrbein & Diedrich 1993, Wehrbein 1994, De Pauw

et al. 1999, Majzoub et al. 1999, Wehrbein et al.

1999a,b). They can thus be used as orthodontic an-

chorage elements as well as anchors for orthopedic

treatment tasks in the maxillofacial complex.

From the clinical standpoint it is of some relevance

whether implants are used only temporarily as ortho

dontic anchorage elements for the correction of a mal

occlusion, and subsequently as abutments to

support

a fixed prosthetic appliance (orthodontic-

prosthetic

implant anchorage (OPIA)), or whether

they are to

function exclusively as orthodontic

anchorage ele

ments (orthodontic implant anchorage

(OIA)). These

aspects determine factors such as

insertion site and

implant type and dimension, as

well as the type of orthodontic implant anchorage.

IMPLANTS USED FOR ANCHORAGE IN ORTHODONTIC THERAPY • 1005

Fig. 43-1. (a) Osseointegrated prosthetic implant (Branemark, length 10 mm) used as orthodontic anchor to distal-

ize premolars in an experimental study in dogs. Horizontal loading of 2 N for 26 weeks. (b,c) Histologic sections (

staining: toluidine blue, original magnification x 2, orientation: sagittal plane) of a non-loaded control (b) and

loaded test implant (c). The test implant reveals a broader peri-implant hard tissue casing. (d,e) Fluorescent mi-

crographs (x 25) from the apical part of the control (d) and the test implant (e). Note the higher remodeling

activity and the multiple bony apposition lines at the test implant. (f) Fluorescent micrograph (x 25) from the

marginal bone (pressure side) of a test implant. Note the multiple bony apposition lines adjacent to the implant.

Such an amount of apposition was not detected in any of the controls (material from the study by Wehrbein &

Diedrich 1993).

1oo6 •

CHAPTER 43

Fig. 43-2. Orthodontic-prosthetic implant anchorage. (a) Bilaterally missing P2, Ml and M2. Both M3 are tipped to

mesial. Radiograph (b) before and (c) after uprighting. Uprighting was done by moving the molar root

mesially through the bone. This type of uprighting needs high-capacity anchorage units. The advantage of using

implants as anchors is that the anterior dentition is not loaded for anchorage purposes, therefore side effects such

as protrusion of the anterior teeth are avoided.

ORTHODONTIC-PROSTHETIC

IMPLANT ANCHORAGE

(OPIA)

In the OPIA technique, the insertion site is determined

fundamentally by the subsequent use of the implant

as a prosthetic abutment. For this reason conventional

prosthetic implants are inserted into the alveolar part

of the mandible or the maxilla. However, the number

of implants and their position within the alveolar

process have to be selected with reference to prospec-

tive aspects, i.e. the position of the teeth after ortho-

dontic treatment is dictated by the number of implants

and their position. It may be helpful in this context to

prepare a preimplantologic set-up.

For OPIA, an orthodontic attachment such as a

bracket or band is fixed at the provisional crown or

prefabricated bonding bases. The orthodontic force

system acts at the superstructure of the implant. The

reactive moments and forces applied in moving teeth

are thus transmitted directly to the implant and its

surrounding bone. Biomechanically speaking, this is

a direct implant anchorage type.

Potential peri-implant reactions/orthodontic

load

As occlusal loading conditions are not comparable to

orthodontic loading conditions, it is important to

know what effects long-term orthodontic loading con-

ditions (e.g. magnitude of loading: up to 5 N; type of

loading: continuous; duration of loading: more than 6

months; loading directions: intrusive/extrusive hori-

zontally as well as rotational) may have on the peri-

implant bone. This question is of special interest be-

cause the orthodontic load should not have a negative

impact on the peri-implant bone and as such impair

the long-term prognosis of the implant as a prosthetic

abutment. In an experimental study, Wehrbein & Die-

drich (1993) investigated the positional stability and

the effect of long-term orthodontic loading on the

peri-implant bone of osseointegrated prosthetic im-

plants (titanium screws, length: 10 mm). The ortho-

dontically loaded test implants were compared with

non-loaded controls after a 26-week implant loading

period with horizontally acting continuous forces of 2

N. The findings were positional stability and mainte-

nance of osseointegration of loaded implants. In com-

parison with the control implants, some test implants

revealed a broader peri-implant hard tissue fraction

and marginal bone apposition (Fig. 43-1). Analysis of