Download Infrabony Pockets and Reduced Alveolar Bone Height

<< :,¢J,. a >>
Home
Infrabony Pockets and Reduced
Alveolar Bone Height in Relation
to Orthodontic Therapy
Birgit Thilander
Experimental animal studies have shown that orthodontic movement of
teeth into infrabony pockets may be detrimental to the periodontal attachment. After elimination of subgingival plaque infection in the experimental
animals, no additional loss of connective tissue attachment occurred. An
experimental model has shown that a tooth with normal periodontal
support can be orthodontically moved into an area of reduced bone height
with maintenance of height of connective tissue attachment level and
alveolar bone support. The results from these experimental studies have
been tested clinically. (Semin Orthod 1996;2:55-61.) Copyright © 1996 by
W.B. Saunders Company
he question of whether orthodontic tooth
T m o v e m e n t may have deleterious effects on
the periodontal tissues has b e e n evaluated in a
n u m b e r of clinical and experimental studies.
The results have shown that, provided periodontal health and p r o p e r oral hygiene standards a r e
maintained during the phase of orthodontic
therapy, no injury, or only clinically insignificant
injury to the supporting tissues will occur. However, if the oral hygiene is less effective and
periodontal inflammation is present during the
orthodontic treatment, the studies have indicated an increased risk for adverse effects on the
periodontium. This is i m p o r t a n t to remember, if
orthodontic tooth m o v e m e n t s should be perf o r m e d in areas with infrabony pockets or in
areas of reduced height of alveolar bone. This
article will discuss relevant studies, together with
some clinical applications, to improve our understanding of the advantages as well as the disadvantages of orthodontic treatment in such patients.
From the Department of Orthodontics, G6teborg University,
G6teborg, Sweden.
Address correspondenceto Bbgit Thiland~ Odont Dr, MD(hc),
Department o[Orthodontics, Faculty of Odontology, G6teborgUnivo=
sity, Medicinaregatan 12, S-41390 G&eborgSweden.
Copyright© 1996 by W..B.Saunders Company
1073-8746/96/0201-000855.00/0
Periodontal Tissue Response to
Orthodontic Movement of Teeth With
Infrabony Pockets
Experimental studies involving histological analysis have reported that orthodontic forces per se
are unlikely to convert gingivitis into a destructive periodontitis. 1,2 T h e d e v e l o p m e n t of destructive periodontal disease, however, may result in
the formation of infrabony pockets, ie, angular
bony defects with inflamed connective tissues
and the dentogingival epithelium located apical
to the crest of the alveolar bone. 3
Thus, it can be stated that orthodontic movem e n t of teeth with healthy periodontal tissues
will not cause loss of connective tissue attachment. 4-6 Also in areas with the presence of
plaque-induced suprabony lesions, orthodontic
forces per se have b e e n shown to be incapable of
causing accelerated destruction of the periodontal support. 6,7 This may be explained by the fact
that the effect of orthodontic forces is generally
confined to that portion of the p e r i o d o n t i u m
which is b o r d e r e d by hard tissues on both sides,
whereas the suprabony connective tissue remains unaffected, because the latter portion will
not be compressed between the hard tissues.
However, it has also been shown that in buccal
sites with gingival inflammation and where the
tooth is moved out through the alveolar b o n e
Seminars in Orthodontics, Vol 2, No 1 (March), 1996: pp 55-61
55
I TOC
I Bndex
<<AFJce >>
Home I TOC I Bndex
56
Birigit Thilander
(ie, a buccal b o n e dehiscence is created), gingival recession and c o n c o m i t a n t loss of connective
tissue a t t a c h m e n t may occur, if the covering soft
tissue is thin. 7,s It is most likely, however, that the
causative factor for this destruction is the plaqueinduced lesion, rather than the orthodontic
trauma, because similar orthodontic m o v e m e n t
of teeth with healthy marginal periodontal tissues did not result in a t t a c h m e n t loss. 9,1°
T h e position of the plaque-induced lesion
may, however, be shifted f r o m a suprabony to an
infrabony position, ie, into the area where orthodontic forces affect the periodontium, when
tooth m o v e m e n t directed at tipping or intruding
a tooth into the alveolar b o n e is p e r f o r m e d .
U n d e r these conditions an e n h a n c e d rate of
periodontal destruction is evident, u Thus, infrabony pockets may be created by orthodontic
tipping a n d / o r intruding m o v e m e n t s of teeth
h a r b o r i n g bacterial plaque. D e e p e n e d gingival
pockets must be eliminated before any orthodontic tooth m o v e m e n t is started. After the orthodontic treatment, additional surgical pocket elimination is also p e r f o r m e d , if necessary. 2
In patients who have periodontal disease infrabony pockets are frequently found. W h e t h e r
orthodontic tooth m o v e m e n t in areas with infrabony pockets may have a detrimental effect on
the supporting tissues, has been discussed.
O r t h o d o n t i c elimination of an infrabony
pocket by tooth extrusion has shown a maintained relationship between the c e m e n t o - e n a m e l
junction and the b o n e crest, ie, the b o n e followed the tooth during the extrusion movemerit. 12 In contrast, teeth subjected to extrusion
with concomittant fiberotomy, ie, the coronal
portion of the fiber a t t a c h m e n t was excised, the
crestal part of the alveolar b o n e did not follow
the root during extrusion, and consequently, the
root m o v e m e n t resulted in an increased distance
between the c e m e n t o - e n a m e l j u n c t i o n and the
alveolar b o n e crest. 12q5 Because of the o r t h o d o n tic extrusion, the tooth will be in supraocclusion.
Hence, the crown of the tooth will n e e d to be
shortened, in some cases followed by e n d o d o n t i c
treatment.
T h e effect of bodily m o v e m e n t of teeth into
infrabony periodontal defects has b e e n evaluated in experimental studies in the m o n k e y 5 and
in the dog. 16 If periodontal t r e a t m e n t was perf o r m e d before the orthodontic tooth m o v e m e n t
was started, and the monkeys were subjected to
plaque control measures during the entire course
of the experiment, no deleterious effect was
obtained on the level of the connective tissue
attachment. 5 It was reported, that the angular
bony defect was eliminated by the orthodontic
treatment, but no coronal shift (gain) of the
connective tissue a t t a c h m e n t was found. Hence,
a thin junctional epithelium covered the root
surface to a level c o r r e s p o n d i n g to the pretreatmerit position of the connective tissue attachment.
On the other hand, experiments in dogs have
shown that orthodontic therapy involving bodily
m o v e m e n t of teeth with inflamed, infrabony
pockets may e n h a n c e the rate of loss of the
connective tissue attachment. 16 In each dog, one
p r e m o l a r was moved away f r o m the angular bony
defect and one p r e m o l a r into and through the
angular bony defect (Fig 1). After orthodontic
t r e a t m e n t (5 to 6 months), the teeth were
stabilized for 2 months. Clinical, radiographic,
and histological evaluations showed that it was
possible to establish and maintain an infrabony
pocket with a subcrestal, plaque-induced inflamm a t o r y leason during the entire course of the
study. Although the control teeth had maintained their a t t a c h m e n t levels, all but one of the
orthodontically m o v e d teeth showed additional
loss of a t t a c h m e n t (Fig 2). The risk for additional a t t a c h m e n t loss was particularly evident
when the tooth was m o v e d into the infrabony
pocket.
In conclusion, e x p e r i m e n t a l studies in monkeys and dogs have shown that orthodontic
m o v e m e n t of teeth into infrabony pockets may
be detrimental for the periodontal attachment.
After elimination of the subgingival plaque infection, no additional loss of connective tissue
a t t a c h m e n t occurred. The consequence from
these experimental results is that elimination of
plaque-induced lesions must p r e c e d e the orthodontic treatment. This hypothesis has b e e n
tested in a series of patients with infrabony
pockets resulting f r o m periodontal disease (Fig
3) .2 Clinical and radiographic observations have
shown, that orthodontic treatment can be successfully p e r f o r m e d in such cases, provided that
periodontal t r e a t m e n t directed at the elimination of the plaque-induced lesion precedes the
initiation of orthodontic therapy, and that p r o p e r
oral hygiene is maintained during the course of
orthodontic treatment.
< < :"d-'.l,-
Home I TOC I Bndex
¢:- > >
Infrabony Pockets and Reduced Alveolar Bone Height
Figure 1. Clinical appearance (A) of the two to three
walled angular bony defect (arrow), extending to a
level corresponding to about 50% of the root length.
A notch was prepared at the bottom of the angular
defect. The tooth was then moved away from, or into
and through the defect (open arrows). Radiographs
obtained at the start of the orthodontic tooth movement (B) and at termination of the experimental
period (C). Arrow indicates the direction of tooth
movement, ie, away from the defect. The displacement of the tooth is related to the titanium pins,
inserted in the buccal cortical bone. (Figs 1 (B-C)
reprinted with permission.16)
P e r i o d o n t a l T i s s u e R e s p o n s e to
O r t h o d o n t i c M o v e m e n t of T e e t h
i n t o E d e n t u l o u s Areas w i t h R e d u c e d
Bone Height
In patients with partially edentulous dentitions,
because of congenitally absent or the extraction
of teeth, orthodontic treatment often has to be
performed. By positioning the teeth toward, or
57
into, the e d e n t u l o u s area, i m p r o v e d esthetic a n d
functional results may be g a i n e d J 8-2° In m a n y o f
these individuals there is a r e d u c e d alveolar
b o n e height.
O r t h o d o n t i c forces, i n d u c e d for bodily t o o t h
m o v e m e n t , will result in different reactions in
the p e r i o d o n t a l tissues o n the pressure a n d o n
the tension sides. B o n e r e s o r p t i o n occurs on the
pressure side as a c o n s e q u e n c e o f t r a u m a i n d u c e d reactions within the p e r i o d o n t a l ligam e n t tissue, whereas o n the tension side a
c o n t i n u o u s b o n e apposition will be seen resulting in a m a i n t a i n e d width o f the p e r i o d o n t a l
ligament. 21
T h e tissue c h a n g e s o c c u r r i n g o n the pressure
side d u r i n g o r t h o d o n t i c t o o t h m o v e m e n t are
c o n f i n e d to the i n f r a b o n y area o f the root, ie, the
area o f s u p p o r t i n g b o n e where the p e r i o d o n t a l
l i g a m e n t will be c o m p r e s s e d between the two
h a r d tissues. H e n c e , o r t h o d o n t i c t o o t h movem e n t will n o t i n d u c e reactions in the supracrestal area resulting in loss o f connective tissue
attachment. 7,9,1° T h e applied forces will lead to
demineralization o f the s u p p o r t i n g bone, which
in t u r n allows the t o o t h to move in the direction
o f the force. N o b o n e remineralization is observed adjacent to a t o o t h that has b e e n m o v e d
o u t t h r o u g h the b o n y plate, ie, w h e n an alveolar
b o n e d e h i s c e n c e has b e e n created. 7,8,9 However,
w h e n such a t o o t h is m o v e d back into the
alveolar b o n e housing, b o n e apposition will take
place in t h e a r e a o f t h e p r e v i o u s dehiscence. 9,~°,22,23 T h e results o f these studies indicated that the soft tissue, facial to a p r o d u c e d
b o n e dehiscence, contains a b o n e matrix with
the capacity to remineralize following repositioning o f the t o o t h into the alveolar process. It may
thus be speculated, that genetic factors controlling the d i m e n s i o n s o f the alveolar process may
be the reason f o r the lack o f remineralization o f
the b o n e matrix buccal to a t o o t h which has
b e e n m o v e d buccally o u t o f the alveolar h o u s i n g
o n the buccal side o f the dental arch.
H e n c e , based on the findings in the studies
r e f e r r e d to, it c o u l d be anticipated that, as long
as o r t h o d o n t i c t o o t h m o v e m e n t is p e r f o r m e d
within the genetically d e t e r m i n e d b o u n d a r i e s o f
the jaw, the t o o t h will m a i n t a i n the original
h e i g h t o f the s u p p o r t i n g apparatus, ie, its c o n n e c tive tissue a t t a c h m e n t level a n d its alveolar b o n e
height. A n e x p e r i m e n t a l m o d e l in a beagle d o g
<< :,¢J,. a >>
Home
58
Birigit Thilander
Figure 2. Specimens from a tooth orthodontically moved into (A) and away from (B) the infrabony pocket,
showing presence of an inflammatory cell infiltrate in the connective tissue adjacent to the pocket epithelium.
The termination of the dentogingival epithelium (aJE) apical to the notch (N) indicates additional loss of
connective tissue attachment, when the tooth is moved into the defect. (Fig 2(A) reprinted with permission. 16)
Figure 3. A 40-year-old
woman had had periodontal treatment for the infrabony pocket mesial to the
maxillary left central incisor (A and D). Proper oral
hygiene was maintained,
and the spaces in the anterior segment were closed by
means of a fixed appliance
using very light forces. Semipermanent retention performed 6 months later. A
further control 6 months
later showed improvement
of the bony defect (B and
E). Permanent retention then
was carried out. Posttreatment control 5 years later (C
and F). Note the improveinent of the bony defect. (Reprinted with permission.21)
I TOC
I Bndex
< < :"d-'J~- ?:- > >
Home I TOC I Bndex
[nfrabony Pockets and Reduced Alveolar Bone Height
was designed to test this hypothesis by o r t h o d o n tically moving teeth into edentulous areas with
reduced b o n e height (Fig 4).24 None of the teeth
whether moved orthodontically or not, showed
loss of connective tissue a t t a c h m e n t (Figs 5 and
6). Hence, at all teeth, the most apical cells of the
junctional epithelium were located at the cem e n t o - e n a m e l junction (CEJ). T h e newly established periodontal ligament exhibited a n o r m a l
width, both on the pressure and on the tension
side of the displaced teeth.
On the tension side both the original height
and width of the supporting bone were fully
maintained. On the pressure side, supporting
alveolar b o n e was also present, extending far
coronal to the surrounding, experimentally created b o n e level, but not reaching the complete
height as the original supporting bone. It is
obvious when analyzing the histological sections,
that the supporting b o n e on the pressure side,
not visualized in the radiograph, was m u c h
thinner than the original bone. The histological
picture of the b o n e tissue in the coronal portion
of the root showed a high n u m b e r of cells in
contrast to the compact a p p e a r a n c e of the m o r e
apically located b o n e (Fig 6). The explanation
for this finding can only be speculated on.
)-
Figure 5. Radiographs obtained at the start of the
orthodontic movement (A) and at the termination of
the experiment (B) of a test tooth and the contralateral control tooth. Note the difference in radiographic bone height (arrows). Titanium pins indicate
the displacement of the test tooth. (Reprinted with
permission. ~4)
Following similar tooth m o v e m e n t in a facial
direction outside the boundaries of the jaw, no
b o n e remineralization will be found. 7,l° In contrast to the heavy forces used when moving teeth
out buccally through the bony plate, only very
light forces were applied when moving the teeth
bodily into the area with reduced bone height.
The use of light forces may explain that, only the
inorganic c o m p o n e n t of the alveolar b o n e was
lost, as a consequence of the biological response
to the orthodontic force, and that the organic
c o m p o n e n t was maintained which was likely to
result in remineralization of bone. The interesting finding, that the newly f o r m e d b o n e on the
pressure side shows resorption on the surface
n e a r the root and apposition on the opposite
side of the thin b o n e plate, may also be exp l a i n e d by the piezoelectrical theory. T h e
changes that occur in alveolar b o n e during tooth
m o v e m e n t have been interpreted to be related
to a piezoelectrical effect through strain-generated potentials, arising as a result of mechanically induced deformation of collagen or hydroxyapatite crystals. 25
In conclusion, an experimental model has
shown that a tooth with n o r m a l periodontal
support can be orthodontically m o v e d into an
area of reduced b o n e height with maintained
height of the supporting apparatus, ie, main-
iiii!!iiiiiiiiiiiii!iiiiiiiiiiiiiiliiiiiiiiiiiiiiiiiiiiii
Figure 4. Schematic drawing (A) and clinical photograph (B) illustrating the bodily movement of the
third premolar into tile area with reduced alveolar
bone height. (Fig 4(A) reprinted with permission. 24)
59
<< :,¢J,. ~ >>
Home
60
Birigit Thilander
Figure 6. Specimens from
the control (A) and the test
tooth (B and C magnification), shown in Figure 5.
The thin bone along the
pressure side of the test tooth
is not visualized in the radiograph. (Reprinted with permission. 24)
t a i n e d c o n n e c t i v e tissue a t t a c h m e n t level a n d in
all essentials m a i n t a i n e d a l v e o l a r b o n e s u p p o r t .
T h e s e e x p e r i m e n t a l results have b e e n t e s t e d in
p a r t i a l l y e d e n t u l o u s p a t i e n t s with n o r m a l p e r i o d o n t a l tissue s u p p o r t , l o c a t e d a d j a c e n t to a n
e d e n t u l o u s a r e a with r e d u c e d b o n e v o l u m e .
T e e t h have b e e n o r t h o d o n t i c a l l y m o v e d i n t o
such an a r e a a n d u s e d for a f i x e d p a r t i a l d e n t u r e
(Fig 7).17 T h e results o f t h e s e clinical follow-up
studies a r e e n c o u r a g i n g , p r o v i d e d t h a t b o d i l y
t o o t h m o v e m e n t s with l i g h t o r t h o d o n t i c forces
a r e used, a n d p r o p e r o r a l h y g i e n e is m a i n t a i n e d .
Figure 7. A 25-year-old man
partially edentulous because
of trauma. Marked bone loss
in the left maxillary alveolar
process (A, B, C, and D)
(indicated by arrows). The
second premolar was moved
bodily one cusp width into
the area with reduced bone
support (E). After a treatment period of 12 months,
a prosthetic bridge was constructed. Note the regaining of alveolar bone (F).
(Reprinted with permission. 21)
I TOC
I Bndex
< < :"d-'J,- ?:- > >
Home I TOC I Index
Infrabony Pockets and Reduced Alveolar Bone Heigkt
References
1. Lindhe J, Nyman S, Ericsson I. Trauma frmu occlusion,
In: Lindhe J, editor. Textbook of Clinical Periodontology
(ed 2). Copenhagen, Munksgaard, 1989:240-257.
2. Thilander B. Orthodontic tooth movement in periodontal therapy, In: Lindhe J, editor. Textbook of Clinical
Periodontology (ed 2). Copenhagen, Munksgaard, 1989:
563-589.
3. WaerhaugJ. The infrabony pocket and its relationship to
trauma from occlusion and subgingival plaque. J Periodonto11979;50:355-365.
4. Polson A, Zander H. Effect of periodontal trauma upon
infrabony pockets.J Periodonto11983;54:586-591.
5. Polson A, CatonJ, Polson AP, et al. Periodontal response
after tooth movement into infrabony defects. J Periodontol 1984;55:197-202.
6. Ericsson I, Thilander B, LindheJ. Periodontal conditions
after orthodontic tooth movement in the dog. Angle
Orthod 1978;48:210-218.
7. Wennstr6mJ, LindheJ, Sinclair F, et al. Some periodontal tissue reactions to orthodontic tooth movement in
monkeys. J Clin Periodontol 1987;14:121-129.
8. Steiner G, Pearson J, AinamoJ. Changes of the marginal
periodontium as a result of labial tooth movement in
monkeys.J Periodonto11981;52:314-320.
9. Karring T, Nyman S, Thilander B, et al. Bone regeneration in orthodontically produced alveolar bone dehiscences. J Periodont Res 1982;17:309-315.
10. Thilander B, Nyman S, Karring T, et al. Bone regeneration in alveolar bone dehiscences related to orthodontic
tooth movements. EurJ Orthod 1983;5:105-114.
11. Ericsson I, Thilander B, Lindhe J, et al. The effect of
orthodontic tilting movements on the periodontal tissues of infected and non-infected dentitions in dogs. J
Clin Periodontol 1977;4:278-293.
12. Berglundh T, Marinello C, Lindhe J, et al. Periodontal
tissue reactions to orthodontic extrusion.J Clin Periodontol 1991;18:330-336.
13. Pontoriero R, Celenza E Ricci G, et al. Rapid extrusion
with fiber resection: a combined orthodontic-periodon-
14.
15.
16.
17.
18.
19.
61
tic treatment modality. IntJ Period Restor Dent 1987;7:3143.
Kozlowsky A, Tal H, Liebermann M. Forced eruption
combined with gingival fiberotomy. J Clin Periodontol
1988;15:534-538.
Schwimer CW, Rosenberg ES, Schwimer DH. Rapid
extrusion with fiberotomy. J Esther Dent 1990;2:82-88.
Wennstr6m J, Lindskog-Stokand B, Nyman S, et al.
Periodontal tissue response to orthodontic movement of
teeth with infrabony pockets. Am J Orthod Dentofacial
Orthop 1993;103:313-319.
Thilander B, Wisth PJ. Orthodontic treatment in adults,
In: Thilander B, R6nning O, editors. Introduction to
Orthodontics (ed 2). Solna, Gothia-LIC F6rlag, 1995;209238.
Stepovich ML. A clinical study on closing edentulous
spaces in the mandible. Angle Orthod 1979;49:227-233.
Horn BM, Turley PK. The effects of space closure on the
mandibular first molar area in adults. Am J Orthod
1984;85:457-469.
20. Goldberg D, Tnrley E Orthodontic space closure of
edentulous maxillary first molar area in adults. Int J
Adult Orthod Orthognath Surg 1989;4:255-266.
21. Rygh P. Orthodontic forces and tissue reactions, In:
Thilander B, R6nning O, editors. Introduction to Orthodontics (ed 2). Solna, Gothia-LIC F6rlag, 1995:175-194.
22. Nyman S, Karring T, Bergenhohz G. Bone regeneration
in alveolar bone dehiscences produced byjiggling forces.
J Clin Periodonto11982;7:316-322.
23. Engelking G, Zachrisson B. Effects of incisor repositioning on monkey periodontium after expansion through
the cortical plate. AnaJ Orthod 1982;82:2.3-32.
24. Lindskog-Stokland B, Wennstr6m J, Nyman S, et al.
Orthodontic tooth movement into edentulous areas with
reduced bone height. An experimental study in the dog.
EurJ Orthod 1993;15:89-96.
25. Zengo A, Pawluk R, Basset C: Stress-induced bioelectric
potentials in the dento-alveolar complex. Am J Orthod
1973;64:17.