Jan Lindhe. Clinical Periodontology

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OCCLUSAL THERAPY • 735

Figs. 30-6. Photomicrograph illustrating the interdental area between two mandibular premolars in the monkey. In

(

a) the two premolars are exposed to jiggling forces. Note the reduction of alveolar bone in the area and the loca-

tion

of the bone crest. Ten weeks after the elimination of the jiggling forces (b) a considerable regeneration of bone

has

occurred. Note the increase of the height of the interdental bone and the normalization of the width of the peri-

odontal ligaments. The apical end of the junctional epithelium is located at the cemento-enamel junction. Courtesy

of Dr Polson; from Poison et al. (1976a).

Figs. 30-7. In the presence of an ex

isting marginal inflammation, al-

veolar bone, lost by jiggling

trauma (

a), will not always regen

erate

following elimination of the

traumatic forces (b). ICT: infil

trated

connective tissue. CEJ: cemento-

enamel junction. JE: apical

end of

junctional epithelium. BC:

alveolar

bone crest. BBD: bottom

of angular

bony defect. From Poi-

son et al. (

1976b).

i.e. trauma from occlusion (Fig. 30-5). If the restoration

so designed that the crown of the tooth in occlusion is

subjected to undue forces directed in a buccal direc-

tion, bone resorption phenomena develop in the buccal-

marginal and lingual-apical pressure zones with a

resulting increase of the width of the periodontal liga-

736 • CHAPTER 30

Figs. 30-8. If a tooth with reduced periodontal tissue

support (a) has been exposed to excessive horizontal

forces, a widened periodontal ligament space

("brown" areas) and increased mobility (arrow) result.

Following reduction or elimination of such forces, bone

apposition will occur and the tooth will become stabi

lized (b).

ment in these zones. The tooth becomes hypermobile

or moves away from the "traumatizing" position.

Since such traumatizing forces in teeth with normal

periodontium or overt gingivitis cannot result in

pocket formation or loss of connective tissue attach-

ment, the resulting increased mobility of the tooth

should be regarded as a physiologic adaptation of the

periodontal tissues to the altered functional demands.

A proper correction of the anatomy of the occlusal

surface of such a tooth, i.e. occlusal adjustment, will

normalize the relationship between the antagonizing

teeth in occlusion, thereby eliminating the excessive

forces. As a result, apposition of bone will occur in the

zones previously exposed to resorption, the width of

the periodontal ligament will become normalized and

the tooth stabilized, i.e. it reassumes its normal mobil

ity (Fig. 30-5). In other words, resorption of alveolar

bone which is caused by trauma from occlusion is a

reversible process which can be treated by the elimi-

nation of occlusal interferences.

The capacity for bone regeneration after resorption

following trauma from occlusion has been docu-

mented in a number of animal experiments (Waer-

haug & Randers-Hansen 1966, Poison et al. 1976a,

Karring et al. 1982, Nyman et al. 1982). In such experi

ments, the induced bone resorption not only involved

the bone within the alveolus but also the alveolar bone

crest. When the traumatizing forces were removed,

bone tissue was deposited not only in the walls of the

alveolus, thereby normalizing the width of the peri-

odontal ligament, but also on the bone crest area,

whereby the height of the alveolar bone was normal-

ized (Fig. 30-6; Poison et al. 1976a). In the presence of

an untreated, plaque-associated lesion in the soft tis-

sue, however, substantial bone regrowth did not al-

ways occur (Fig. 30-7; Poison et al. 1976b) .

Situation II

Increased mobility

of a tooth with increased width of

the periodontal ligament and reduced height of the

alveolar bone

When a dentition has been properly treated for mod-

erate to advanced periodontal disease, gingival health

is established in areas of the dentition where teeth are

surrounded by periodontal structures of reduced

height. If a tooth with a reduced periodontal tissue

support is exposed to excessive horizontal forces (

trauma from occlusion), inflammatory reactions de-

velop in the pressure zones of the periodontal liga-

ment with accompanying bone resorption. These al-

terations are similar to those which occur around a

tooth with normal height of the supporting structures;

the alveolar bone is resorbed, the width of the peri-

odontal ligament is increased in the pressure/ tension

zones and the tooth becomes hypermobile (Fig. 30-8a).

If the excessive forces are reduced or eliminated by

occlusal adjustment, bone apposition to the "pre-

trauma" level will occur, the periodontal ligament will

regain its normal width and the tooth will become

stabilized (Fig. 30-8b).

Conclusion: Situations I and II

Occlusal adjustment is an effective therapy against

increased tooth mobility when such mobility is caused

by an

increased width

of the periodontal ligament.

Situation III

Increased mobility of a

tooth

with reduced

height of

the alveolar bone and normal width of the

periodontal ligament

The increased tooth mobility which is the result of a

reduction in height of the alveolar bone without a

concomitant increase in width of the periodontal

membrane cannot be reduced or eliminated by oc-

OCCLUSAL THERAPY • 737

Fig. 30-9. Case A, 64-year-old male. Periodontal status and radiographs prior to therapy.

clusal adjustment. In teeth with normal width of the

periodontal ligament, no further bone apposition on

the walls of the alveoli can occur. If such an increased

tooth mobility does not interfere with the patient's

chewing function or comfort, no treatment is required.

If the patient experiences the tooth mobility as dis-

turbing, however, the mobility can in this situation be

reduced only by splinting, i.e. by joining the mobile

tooth/teeth together with other teeth in the jaw into a

fixed unit — a SPLINT.

A SPLINT, according to the Glossary of Periodontic

Terms (1986) is "an appliance designed to stabilize

mobile teeth". A splint can be fabricated in the form of

joined composite fillings, fixed bridges, removable

partial prostheses, etc.

Example: Case

64-year-old

male

The periodontal condition of this patient is illustrated

by the probing depth, furcation involvement and

tooth

mobility data as well as the radiographs from

the

initial examination in Fig. 30-9. Periodontal dis

ease

has progressed to a level where, around the maxillary

teeth, only the apical third or less of the roots is

invested in supporting alveolar bone. The following

discussion is related to the treatment of the maxillary

dentition.

In the treatment planning of this case it was decided

that the first premolars (teeth 14 and 24) had to be

extracted due to advanced periodontal disease and

furcation involvement of degree III. For the same rea-

sons, teeth 17 and 27 were scheduled for extraction.

Teeth 16 and 26 were also found to have advanced loss

of periodontal tissue support in combination with

deep furcation involvements. The most likely

definitive

treatment should include periodontal and adjunc

tive

therapy in the following parts of the dentition: 15

and

25, and 13, 12, 11, 21, 22, 23. For functional and

esthetic reasons, 14 and 24 obviously had to be re-

placed. The question now arose as to whether these

Periodontal chart

Tooth

Pocket depth

Furcation

involvement

Tooth

mobility

B D

17 6 6

8 8

b2,m2,dl

16 6 6

8 8

m1, d2 2

8 8

6 7 2

14 7 7 7 4

4 2

6 4 7 4

21 6 4 6 4

22 6 5 7 2

23 6 6 4 2

24 7

3 2

25 6

8 8

4 2

b2, m2, d2

27 6 6

10 8

b2, d2

2-8

6 6 7

b1, 12

45 6 7 4

44 6

43 7 7 6 4

42 4 4 4

41 6 4

31 6

32 4 6 4

33 6 6 6 2

34 4 7 4

35 7 4 6 2

5 6 4

b2, 12

two premolars should be replaced by two separate

unilateral bridges, using 13, 15 and 23, 25 as abutment

teeth, or if the increased mobility of these teeth and

738 • CHAPTER 30

Fig. 30-10. Case A. Radiographs obtained 10 years after periodontal therapy and installation of two unilateral

bridges in the maxilla.

also of the anterior teeth (12, 11, 21, 22; Fig. 30-9) called

for a bridge of cross-arch design, with the extension

15-25, to obtain a splinting effect. If 14 and 24 are

replaced by two unilateral bridges, each one of these

3-unit bridges will exhibit the same degree of mobility

in buccolingual direction as the individual abutment

teeth (degree II: Fig. 30-9), since a unilateral straight

bridge will not have a stabilizing effect on the abut-

ment teeth in this force direction.

From the radiographs it can be seen that the in-

creased mobility observed in the maxillary teeth of

this patient is associated mainly with reduced height

of the alveolar bone and not with increased width of

the periodontal ligaments. This means that the mobil

ity of the individual teeth should be regarded as nor-

mal or "physiologic" for teeth with such a reduced

height of the supporting tissues. This in turn implies

that the increased tooth mobility in the present case

does not call for treatment unless it interferes with the

chewing comfort or jeopardizes the position of the

front teeth. This particular patient had not recognized

any functional problems related to the increased mo-

bility of his maxillary teeth. Consequently, there was

no reason to install a cross-arch bridge in order to

splint the teeth, i.e. to reduce tooth mobility.

Following proper treatment of the plaque-associ-

ated periodontal lesions, two separate provisional

bridges of unilateral design were produced (15, 14, 13;

23, 24, 25, 26 palatal root). The provisional acrylic

bridges were used for 6 months during which the

occlusion, the mobility of the two bridges and the

position of the front teeth were all carefully monitored.

When, after 6 months, no change of position of the

lateral and central incisors had occurred and no in-

crease of the mobility of the two provisional bridges

had been noted, the definitive restorative therapy was

performed.

Fig. 30-10 presents radiographs obtained 10 years

after initial therapy. The position of the front teeth and

the mobility of the incisors and the two bridges have

not changed during the course of the maintenance

period. There has been no further loss of periodontal

tissue support during the 10 years of observation, no

further spread of the front teeth and no widening of

the periodontal ligaments around the individual

teeth, including the abutment teeth for the bridge-

work.

Conclusion: Situation III

Increased tooth mobility (or bridge mobility) as a

result of reduced height of the alveolar bone can be

accepted and splinting avoided, provided the occlu-

sion is stable (no further migration or further increas-

ing mobility of individual teeth), and provided the

degree of existing mobility does not disturb the pa-

tient's chewing ability or comfort. Consequently,

splinting is indicated when the mobility of a tooth or

group of teeth is so increased that chewing ability

and/or comfort are disturbed.

Situation

Progressive (increasing) mobility of a tooth (teeth) as

result of gradually increasing width of the reduced

periodontal ligament

Often in cases of advanced periodontal disease the

tissue destruction may have reached a level where

extraction of one or several teeth cannot be avoided.

Teeth which in such a dentition are still available for

periodontal treatment may, after therapy, exhibit such

a high degree of mobility - or even signs of progres-

sively increasing mobility - that there is an obvious

risk that the forces elicited during function may me-

chanically disrupt the remaining periodontal liga-

ment components and cause extraction of the teeth.

OCCLUSAL THERAPY • 739

Fig. 30-11. Case B, 26-year-old male. Radiographs illustrating the periodontal conditions prior to therapy.

Fig. 30-12. Case B. Radiographs obtained after periodontal treatment and preparation of the abutment teeth for two

fixed splints.

Only by means of a splint will it be possible to main-

tain such teeth. In such cases a fixed splint has two

objectives: (1) to stabilize hypermobile teeth and (2) to

replace missing teeth.

Example: Case

B, 26-year-old male

Fig. 30-11 presents radiographs taken prior to therapy

and Fig. 30-12 those obtained after periodontal treat-

ment and preparation of the remaining teeth as abut-

ments for two fixed splints. All teeth except 13, 12 and

33 have lost around 75% or more of the alveolar bone

and widened periodontal ligaments are a frequent

finding. The four distal abutments for the two splints

are root-separated molars, the maintained roots being

the following: the palatal root of 17, the mesiobuccal

root of 26 and the mesial roots of 36 and 47. It should

be observed that tooth 24 is root-separated and the

palatal root maintained with only minute amounts of

periodontium left. Immediately prior to insertion of

the two splints, all teeth except 13, 12 and 33 displayed

a mobility varying between degrees 1 and 3. From the

radiographs in Fig. 30-12 it can be noted that there is

an obvious risk of extraction of a number of teeth such

as 24, 26, 47, 45, 44, 43 and 36 if the patient is allowed

to bite with a normal chewing force without the splints

in position.

Despite the high degree of mobility of the individ

ual

teeth, the splints were, after insertion, entirely

stable

and have maintained their stability during a

maintenance period of more than 12 years. Fig. 30-13

describes the clinical status and Fig. 30-14 presents the

radiographs obtained 10 years after therapy. From

these radiographs it can be observed (compare with

Fig. 30-12) that during the maintenance period there

has been no further loss of alveolar bone or widening

of the various periodontal ligament spaces.

740 • CHAPTER 30

Fig. 30-13. Case B. Clinical status 9 years after therapy.

Fig. 30-14. Case B. Radiographs obtained 10 years after therapy.

Conclusion: Situation IV often be observed that the destruction of the periodon-

Splinting is indicated when the periodontal support tium has progressed to varying levels around different

is so reduced that the mobility of the teeth is progres-

teeth and tooth surfaces in the dentition. Proper treat-

sively increasing, i.e. when a tooth or a group of teeth ment of the plaque-associated lesions often includes

during function are exposed to extraction forces.multiple extractions. The remaining teeth may display

an extreme reduction of the supporting tissues con-

comitant with increased or progressive tooth mobility.

Situation

They may also be distributed in the jaw in such a way

as to make it difficult, or impossible, to obtain a proper

Increased bridge

mobility despite splinting splinting effect even by means of a cross-arch bridge.

In patients with advanced periodontal disease it can

OCCLUSAL THERAPY • 741

Fig. 30-15. Case C, 52-year-old female. Radiographs obtained at the initial examination.

Fig. 30-16. Case C. Radiographs obtained 5 years after therapy.

The entire bridge/splint may exhibit mobility in fron-

tal and or lateral directions.

It was stated above (Situation III) that a certain

mobility of a tooth or a bridge of unilateral design can

be accepted provided this mobility does not interfere

with the patient's chewing ability or comfort. This is

also valid for a cross-arch bridge/splint. From a bio-

logic point of view there is no difference between

increased tooth mobility on the one hand and in-

creased bridge mobility on the other. However, neither

progressive tooth mobility nor progressive bridge mo-

bility can be accepted. In cases of extremely advanced

periodontal disease, a cross-arch splint with an in-

creased mobility may be regarded as an acceptable

result of rehabilitation. The maintenance of status quo

of the bridge/splint mobility and the prevention of

tipping or orthodontic displacement of the total splint,

however, requires particular attention regarding the

design of the occlusion. Below, a case is reported

which may serve as an interesting illustration of this

particular clinical problem.

Example: Case C,

52-year-old female

Fig. 30-15 shows radiographs obtained at the initial

examination. A 12-unit maxillary bridge was installed

10-15 years prior to the present examination using 18,

15, 14, 13, 12, 11, 21, 22, 23 and 24 as abutments. After

a detailed clinical examination it was obvious that 15,

14, 22 and 24 could not be maintained because of

severe symptoms of caries and periodontal disease.

The remaining teeth were subjected to periodontal

therapy and maintained as abutments for a new

bridge/splint in the maxilla extending from tooth 18

to the region of 26, i.e. a cross-arch splint was installed

which carried three cantilever units, namely 24, 25 and

26. The mobility of the individual abutment teeth

immediately prior to insertion of the splint was the

following: degree 1 (tooth 18), degree 0 (tooth 13),

742 • CHAPTER

Fig. 30-17. Case C. The cantilever section including

teeth 24, 25 and 26.

degree 2 (teeth 12 and 11), degree 3 (tooth 21) and

degree 2 (tooth 23).

Radiographs obtained 5 years after therapy are

shown in Fig. 30-16. The bridge/splint had a mobility

of degree 1 immediately after its insertion and this

mobility was unchanged 5 years later. The radio-

graphs demonstrate that no further widening of the

periodontal ligament occurred around the individual

teeth during the maintenance period.

When a cross-arch bridge/splint exhibits increased

mobility, the center (fulcrum) of the movement must

be identified. In order to prevent further increase of

the mobility and/or to prevent displacement of the

bridge, it is essential to design the occlusion in such a

way that the bridge/splint, when in contact with the

teeth of the opposing jaw, is subjected to a balanced

load, i.e. equal force on each side of the fulcrum. If this

can be achieved, the force to which the bridge is

exposed in occlusion can be used to retain the fixed

prosthesis in proper balance (further increase of the

mobility being thereby prevented).

Balanced loading of a mobile bridge/splint has to

be established not only in the intercuspal position (IP)

and centric occlusion (CP) but also in frontal and

lateral excursive movements of the mandible if the

bridge shows mobility or a tendency for tipping in the

direction of such movements. In other words, a force

which tends to displace the bridge in a certain direc-

tion has to be counteracted by the introduction of a

balancing force on the opposite side of the fulcrum of

the movement. If, for instance, a cross-arch splint in

the maxilla exhibits mobility in frontal direction in

conjunction with protrusive movements of the man-

dible, the load applied to the bridge in the frontal

region has to be counterbalanced by a load in the distal

portions of the splint; this means that there must be a

simultaneous and equal contact relationship between

the occluding teeth in both the frontal and the poste-

rior regions of the splint. If the splint is mobile in a

lateral direction, the force acting on the working side

of the jaw must be counteracted by a force established

by the introduction of balancing contacts in the non-

working side of the jaw. The principle for establishing

stability of a

mobile

cross-arch splint is consequently

the same as that used to obtain stability in a complete

denture. In situations where distal abutment teeth are

missing in a cross-arch bridge/splint with increased

mobility, balance and functional stability may be ob-

tained by means of cantilever units. It is important in

this context to point out that balancing contacts on the

non-working side should not be introduced in a

bridge/splint in which no increased mobility can be

observed.

The maxillary splint in the patient described in Figs.

30-13 to 30-16 exhibited increased mobility in frontal

direction. Considering the small amount of periodon-

tal support left around the anterior teeth, it is obvious

that there would have been a risk of frontal displace-

ment of the total bridge had the bridge terminated at

the last abutment tooth (23) on the left side of the jaw.

The installation of cantilever units in the 24 and 25

region prevented such a displacement of the

bridge/splint by the introduction of a force counter-

acting frontally directed forces during protrusive

movements of the mandible (Fig. 30-17). In addition,

the cantilever units provide bilateral contact relation-

ship towards the mandibular teeth in the intercuspal

position, i.e. bilateral stability of the bridge.

In cases similar to the one described above, cantile

ver units can thus be used to prevent increasing mo-

bility or displacement of a bridge/splint. It should,

however, be pointed out that the insertion of cantile-

ver units increases the risk of failures of a technical

and biophysical character (fracture of the metal frame,

fracture of abutment teeth, loss of retention, etc).

In cases of severely advanced periodontal disease

is often impossible to anticipate in the planning

phase

whether a bridge/splint after insertion will

show

signs of instability and increasing (progressive)

mobility. In such cases, a provisional splint should

always be inserted. Any alterations of the mobility of

the bridge/splint can be observed over a prolonged

period of time and the occlusion continuously ad-

justed until, after 4-6 months, it is known whether

stability (i.e. no further increase of the mobility) can

be achieved. The design of the occlusion of the provi-

sional acrylic bridge is then reproduced in the perma-

nent bridge construction. If, on the other hand, stabil-

OCCLUSAL THERAPY • 743

ity cannot be obtained, the rehabilitation of the case

cannot be achieved with a fixed splint. The alternative

treatment then is a complete denture or an implant

supported restoration.

Conclusion: Situation

An increased mobility of a cross-arch bridge/splint

can be accepted provided the mobility does not dis-

turb chewing ability or comfort and the mobility of the

splint is not progressively increasing.

REFERENCES

Glickman, I. (1965). Clinical significance of trauma from occlu-

sion.

Journal of the American Dental Association

70, 607-618.

Glickman, 1. (1967). Occlusion and periodontium.

Journal of Den-

tal Research

46,

Supplement, 53.

Glossary of Periodontic Terms (1986).

Journal of Periodontology.

Supplement.

Karring, T., Nyman, S., Thilander, B. & Magnusson, I. (1982).

Bone-regeneration in orthodontically produced alveolar bone

dehiscences.

Journal of Periodontal Research

17, 309-315.

Miihlemann, H.R. (1954). Tooth mobility. The measuring

method.

Initial and secondary tooth mobility.

Journal of Periodontology

25,

22-29.

Miihlemann, H.R. (1960). Ten years of tooth mobility measure-

ments.

Journal of Periodontology

31, 110-122.

Miihlemann, H.R. & Zander, H.A. (1954). Tooth mobility, III. The

mechanism of tooth mobility.

Journal of Periodontology 25,

128.

Nyman, S., Karring, T., & Bergenholtz, G. (1982). Bone regenera-

tion in alveolar bone dehiscences produced by jiggling forces.

Journal of Periodontal Research

17, 316-322.

Poison, A.M., Meitner, S.W. & Zander, H.A. (1976a). Trauma and

progression of marginal periodontitis in squirrel monkeys.

III. Adaptation of interproximal alveolar bone to repetitive

injury.

Journal of Periodontal Research

11, 279-289.

Poison, A.M., Meitner, S.W. & Zander, H.A. (1976b). Trauma and

progression of marginal periodontitis in squirrel monkeys. IV.

Reversibility of bone loss due to trauma alone and trauma

superimposed upon periodontitis.

Journal of Periodontal Re-

11, 290-298.

Schulte, W. (1987). Der Periotest-Parodontalstatus.

Zahnartzliche

Mitteilung 76,

1409-1414.

Schulte, W., Hoedt, B., Lukas, D., Maunz, M. & Steppeler, M.

(

1992). Periotest for measuring periodontal characteristics –

Correlation with periodontal bone loss.

Journal of Periodontal

Research 27,

184-190.

Waerhaug, J. (1979). The infrabony pocket and its relationship to

trauma from occlusion and subgingival plaque.

Journal of

Periodontology 50,

355-365.

Waerhaug, J. & Randers-Hansen, E. (1966). Periodontal changes

incident to prolonged occlusal overload in monkeys.

Acta

Odontologica Scandinavica

24, 91-105.

CHAPTER 31

Orthodontics and

Periodontics

BJORN U. ZACHRISSON

Orthodontic tooth movement in adults with

periodontal tissue breakdown

Orthodontic treatment considerations

Esthetic finishing of treatment results

Retention - problems and solutions

Possibilities and limitations

Specific factors associated with orthodontic

tooth movement in adults

Tooth movement into infrabony pockets

Tooth movement into compromised bone areas

Tooth movement through cortical bone

Extrusion and intrusion of single teeth

Regenerative procedures and orthodontic tooth

movement

Traumatic occlusion and orthodontic treatment

Molar uprighting, furcation involvement

Tooth

movement and implant esthetics

Gingival recession

Labial recession

Interdental recession

Minor surgery associated with orthodontic

therapy

Fiberotomy

Frenotomy

Removal of gingival invaginations

Gingivectomy

Orthodontic treatment may be adjunctive to peri-

odontal therapy. The loss of periodontal support or

teeth may result in elongation, spacing and proclina-

tion of incisors, rotation and tipping of premolars and

molars with collapse of the posterior occlusion, and

decreasing vertical dimension. But orthodontic tooth

movement can also facilitate the management of sev-

eral restorative and esthetic problems in adults. Such

difficulties may be related to subgingivally fractured

lost teeth, tipped abutment teeth, excess spacing,

inadequate implant or pontic space, supra-erupted

teeth, narrow alveolar ridges that prevent implant

placement, and other conditions (Ong et al. 1998). The

purpose of this chapter is to discuss how recent basic

and clinical information maybe used to improve treat-

ment planning, clinical management, and retention

for patients in whom different malocclusions are

caused or complicated by moderate to advanced peri-

odontal destruction.

ORTHODONTIC TOOTH

MOVEMENT IN ADULTS WITH

PERIODONTAL TISSUE

BREAKDOWN

Poorly executed orthodontic treatment in periodontal

patients can certainly contribute to further periodon-

tal tissue breakdown. In particular, the combination of

inflammation, orthodontic forces and occlusal trauma

Fig. 31-1. Adult male patient with advanced periodontitis and marked pathologic migration of the anterior teeth be

fore (left column) and after (right column) periodontal and orthodontic fixed-appliance treatment for 2 years. Clini

cal appearance of the face and dentition are dramatically improved after the combined periodontic/orthodontic

treatment. The dental result is maintained by means of bonded lingual retainer wires. A maxillary two-unit and a

mandibular three-unit bridge were constructed. Some interdental recession was unavoidable in the mandibular an

terior region (d), but it does not show much clinically (b).