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New attachment through periodontal treatment and orthodontic intrusion
New attachment through periodontal treatment and orthodontic intrusion 6. Melssn, N. Agerbaek, J. Eriksen, and S. Terp” Aarhus, Denmark The present study was performed to investigate the tissue reaction related to orthodontic intrusion of teeth with a reduced periodontium and further to evaluate the influence of oral hygiene on this reaction. In each of five Macaca fascicularis monkeys, periodontal tissue breakdown was induced around the premolars and the upper incisors by placing orthodontic elastic ligatures around the teeth. The breakdown procedure was continued until a minimum of four pockets could be measured on probing. Following removal of the elastics, a flap operation was performed. The pocket epithelium and granulation tissue were excised. During the surgical procedure, a notch was placed just above the bone. The teeth were divided postoperatively into four groups according to treatment: group 1 = flap operation, no oral hygiene program; group 2 = flap operation plus oral hygiene program three times per week; group 3 = flap operation plus intrusion, no oral hygiene program; and group 4 = flap operation plus intrusion plus oral hygiene. Groups 3 and 4 were subdivided into two observation periods. A total of 60 teeth corresponding to 120 approximate surfaces were studied. The animals were killed with perfusion; histologic sections were produced and stained alternatively with hematoxylin and eosin, and van Gieson’s solution. The histologic analysis showed that new cementum formation and new collagen attachment were observed following the surgical procedure if the oral hygiene was maintained, but also demonstrated that the intrusion improved the quantity of new attachment if carried out under healthy conditions. New attachment was a consistent finding in group 4, but varied from 0.7 to 2.3 mm. In case of intrusion without oral hygiene, the results varied from moderate new attachment to an aggravation of the periodontal bone loss. On the basis of the results presented here, the combination of periodontal treatment and orthodontic intrusion seems to be a method by which improvement of the periodontal condition can be obtained, provided that both the biomechanical force system and the oral hygiene are kept under control. (AM J ORTHOD DENTOFAC ORTHOP 1968;94:104-16.)
0 rthodontic treatment of patients with periodontal disease has been a controversial topic. Several authors have cast doubt upon the beneficial effect of such treatment1-3 and some have even claimed that it may have a detrimental effect on the periodontium.4” Others, however, have demonstrated in clinical trkU7 and animal experiments’s9 that orthodontic treatment does not enhance gingival inflammation or marginal bone loss and can have a beneficial effect on the periodontal conditions.‘@13 Hitherto, this has been ascribed to an indirect effect of improved oral hygiene possibilities, better gingival shape, and more suitable distribution of occlusal forces. Extrusion has been used in the reshaping of the alveolar process’4-‘6and extrusion followed by intrusion has demonstrated that part of the bone apposition during extrusion can be maintained From the Royal Dental Cokge, Institute of Orthodontics. *University of Aarhus, Institute of Statistics.
104
during subsequent intrusion, provided healthy gingival conditions are maintained during treatment. l7 Several therapeutic procedures have been suggested to accelerate repair of periodontal angular bony defects’*.‘9 but without changing the level of connective tissue attachment.a*3 On the other hand, orthodontic movement of teeth into infrabony defects has been reported to result in new connective tissue attachment.13 However, other authors performing similar experiments have failed to find support for this statement. In experiments with dogs, Ericsson’ tilted molars into intrabony defects and did not find any evidence of new connective tissue attachment. Polson and associate? by means of the same method also were unable to detect any change of the attachment level. It was common in the above-mentioned experiments for the model used to include a tipping movement, with the highest stress distribution in the marginal part of the periodontal ligament.
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New attachment through periodontal
Fig. 1. A and B, Radiographs demonstrating the marginal bone loss in the lower (A) and upper(B) jaws. C, Intraoral photograph taken during the flap operation. A clear bifurcation involvement is seen.
Since a stress distribution in the periodontal ligament seems highly related to the tissue reaction occurring during orthodontic treatment, tipping cannot be compared directly with a controlled intrusion. A bodily intrusion of periodontally involved teeth suffering from horizontal bone loss thus has not been studied. The present study was carried out with the purpose of comparing the tissue reaction following a flap operatior?’ with and without intrusion, and further to analyze the influence of a hygiene regimen on the results. MATERIAL
AND METHODS
Four adult (15-year-old) female and two male (12were used in year-old) monkeys (A4ucuca fusciculuris) the study. At the start of the experiment, the animals showed signs of gingivitis, but no pockets or loss of attachment could be detected. Intraoral radiographs showed a normal level of supporting alveolar bone. Orthodontic elastic ligatures were placed around premolars and maxillary incisors to produce breakdown of the supporting tissues. 23 A new ligature was placed on top of the other every second week for a period of 3 to 4 months, producing a minimum of 4-mm deep pockets. Intraoral radiographs were taken and showed a mini-
treatment and orthodontic
intrusion
105
Fig. 2. Schematic drawing illustrating the measurements taken. AM-& The distance from the apical limitation of the reference notch to the marginal bone level. AM-GM, The distance from the apical limitation of the notch to the gingival margin. AM-EJ, The distance from apical limitation of the notch to the epithelial junction.
mum of 2-mm marginal bone loss and bifurcation involvement when the first phase of the experiment was concluded (Fig. 1, A and B). The pathologically deepened periodontal pockets were treated by a reverse bevel flap operation.23 The root surface was thoroughly scaled and the granulation tissue was carefully removed from the bony margin without any contouring of the bony edges. During the surgical procedure, a reference notch was prepared with a no. 2 round burr into the mesial and distal surfaces of all experimental teeth, just coronal to the margin of the alveolar bone at the most apical part of the epithelial junction. The notch served as a reference (AM) for the measurements made in the histologic sections (Fig. 2). Following the surgical procedure, the right side of the jaws was subjected to an oral hygiene regimen three times a week including meticulous cleansing with a toothbrush soaked in 0.2% chlorhexidine digluconate solution. One week after surgical treatment, an orthodontic appliance was inserted in both jaws. The three molars
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Flg. 3. A, Example of an appliance used for intrusion of two premolars in the nonhygiene side. Note the bleeding on probing. B, Intraoral photograph demonstrating the situation after 3 months of intrusion of one lower premolar on the hygiene side. C, Three months of intrusion. No pockets could be measured clinically around the teeth.
of each segment were fitted with a cast metal splint with double rectangular tubes (0.018 x 0.022 inch) soldered buccally and lingually at the level of the second molar. To the upper incisors, small brackets were bonded and a segment of 0.021 x 0.025inch stainless steel wire was adapted to fit the four incisor brackets passively. In three of the monkeys, the two premolars of each segment were connected by bonding a small piece of multistranded wire to the occlusal surfaces (Fig. 3). In the lower jaw, a piece of 0.018-inch TMA* wire was given a U-formed shape and the legs of the U entered the tubes of the molar splint. The round end of the U touched the occlusal surface of the connected premolars with a force of 20 g (Fig. 3). In the upper jaw, a J-shaped 0.017 x 0.025inch TMA wire was placed in the lingual tube with the round end overriding *0rrnw
Corp.,
Glendora,
Calif.
the premolar segment, again with a force of 20 g. In the remaining two monkeys, only one premolar in each segment was intruded (Fig. 4, A and B); the other served as control. For intrusion of the incisors, a base arch was fitted to the buccal tubes of the upper jaw and adapted to intrude the four upper incisors as a segment with a total force of 40 g measured at the midline, the point of force application being lateral to the lateral teeth. The time of intrusion before killing the animals varied from 3 weeks to 3 and 4 months. The monkeys were killed by means of perfusion with 10% buffered formalin. After the animals were killed, the jaws were excised and placed in fixture. Tissue blocks were then cut out and decalcified in EDTA, dehydrated, and double embedded in paraffin celloidin. Serial sections of 8-km thickness were cut mesiodistally through each tooth segment and the section stained alternatively with he-
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New attachment through periodontal treatment and orthodontic intrusion 107
Fhg. 4. A, Histologic section of premolar following intrusion and hygiene regimen 3 weeks postoperatively. It can be seen that the reference notch (A) is localized below the level of marginal bone (B), that the epithelial junction is at the level of marginal bone (C), and that the cementum is subject to osteoclastic activity (0). Bony island (E) probably cut out during the preparation of the notch is subject to remodeling. B, Same as A in a larger magnification. D and E correspond to D and E in A.
matoxylin and eosin, and van Gieson’s connective tissue stains. The following measurements were carried out in the histologic sections (Fig. 2): 1. The distance from AM (the apical limit of the root note h) to the bone level (AM-BL) . The measurements were considered positive if the bone level was located above the marking. 2. The distance from the level of the gingival margin to the apical limit of the root notch in the approximal surface (AM-GM). The measure-
ments were considered to be positive when the gingival level was placed coronal to the marking. 3. The distance between the most apical part of the junctional epithelium (AM-EJ) and the most apical part of the notch. The measurements were considered positive when the junctional epithelium was coronal to the marking. The last measurements were performed with polarized light, making it possible to follow the course of the collagen fibers.
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Dentofac.
Table I. Distance in millimeters between reference points in the various groups (for abbreviations, see Fig. 2) Orthodontic treatment
Perioireatment
Time 3 weeks
Without
Without
intrusion
\
With
Without
With
hygiene
hygiene
hygiene
intrusion
With
hygiene
I I II I
12-16
weeks
3 weeks
12-16
weeks
3 weeks
12-16 weeks
3 weeks
12 weeks
Variable
N
x
SD
Min
MaX
AM-BL AM-GM AM-U AM-BL AM-GM AM-EJ
4
-0.0
6
2.1 0.0 0.1 1.7 -0.1
0.15 1.12 0.1+ 0.50 0.48 0.67
-0.26 0.58 -0.23 1.85 0.61 -1.85
0.27 3.08 0.23 0.38 2.81 1.08
AM-BL AM-GM AM-EJ AM-BL AM-GM AM-EJ
2
0.5 1.0 0.3 0.4 2.1 0.3
0.96 0.37 0.17 0.21 -0.37 0.32
0.42 1.65 -0.12 0.08 1.65 -0.23
0.58 2.23 0.19 0.73 0.23 0.73
AM-BL AM-GM AM-EJ AM-BL AM-GM AM-EJ
4
0.1 2.0 0.2 0.3 2.8 0.9
0.49 1.13 0.22 0.28 0.94 0.75
-0.54 1.15 0.04 0 1.35 0.12
0.77 3.81 0.58 0.85 4.62 2.09
0.8 3.1 0.5 1.3 3.7 1.5
0.21 0.35 0.19 0.29 0.99 0.76
0.58 2.69 0.42 0.77 2.00 0.70
1.00 3.31 0.77 2.23 5.77 2.35
AM-BL AM-GM AM-EJ AM-BL AM-GM AM-EJ
8
10
2
24
table IIA. Analysis of variance-Intra-
and intergroup variation in attachment level (AM-EJ) (measured in millimeters) on the nonintruded teeth (F value reflects the importance of hygiene) Source
Between
groups
within groups TOTAL
DF 3
11 20
Sum of squares 8.3309 11.4717 19.8026
Mean
squares
2.7770 0.6748
F ratio 4.115
P 0.0230
Table 119. Analysis of variance-Intra-
and intergroup variation in attachment level (AM-EJ) (measured in millimeters) on the intruded teeth (F value reflects the importance of hygiene) Source
DF
Between groups Within groups TOTAL
35 38
3
Sum of squares 72.511 23.196 95.707
STATISTICS
A statistical description of the parameters measured was carried out, followed by a comparison of group means by Student’s t test (Table I). An analysis of variance was used to compare intra- and intergroup
Mean
squares
24.170 0.663
F ratio 36.470
P 0.001
variances within the nonintruded teeth (Table IIA), and within the teeth subjected to intrusion (Table IIB). Finally, a three-way analysis of variance was applied for the evaluation of the weight given to each of the factors involved: time, hygiene, and intrusion (Table III).
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2
treatment and orthodontic
intrusion
Fig. 5. a, Histological section of premolar intruded for 3 weeks but without any hygiene control. The epithelial junction (A) is clearly in the apical part of the reference notch. The marginal bone level fs) is below the reference notch. b, Larger magnification of reference notch in a.
Table ! IlIt . II nportance of hygiene, intrusion, and time, and the interactions on the level of attache lent the distanIce frc3rn
Sumof Source of variation Main effects Hygiene (variable 6) Intrusion (variable 7) Time (variable 8) 2-way interactions Variable 6, variable 7 Variable 6, variable 8 Variable 7, variable 8
119.130 28.089 60.130 0.748 10.297 4.322 2.031 0.707
Explained Residual
129.428 35.462 164.890
TOTAL
*While
squares
hygiene
and intrusion
per se are of significance
DF
6 53 55 (p = 0.001).
Mean square
Significance F
ofF
39.710 28.089 60.130 0.748 3.432 4.322 2.031 0.707
59.349 41.981 89.868 1.118 5.130 6.460 3.036 1.057
0.001 0.001 0.001 0.295 0.003 0.014 0.087 0.309
21.571 0.669 2.795
32.239
0.001
time was of significance
only
in interaction
with hygiene.
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notch. Below this level clear odontoclasts could be detected, indicating resorption (Fig. 4). On the nonhygiene side, the notch was located just coronal to the bone level; the epithelial junction was localized at the apical border of the notch and osteoelastic activity of the marginal bone could be detected (Fig. 5). At the 3-week experiment, there was already a significant difference in the level of the epithelial junction in relation to the notch between the hygiene and nonhygiene groups. Three- to four-month
experiment (Figs. 6 and 7).
Two monkeys were killed after 3 months and two after 4 months of experimentation. Since no significant difference could be verified between the 3- and 4-month experiments, the data obtained from these animals were pOOled.
Fig. 6. A Histologic section of a tooth that has been subject to 3 m,on@ of intrusion and regular hygiene program. The apical root resorption (A) is only moderate.
RE$lJLTS
Twelve teeth were lost due to exfoliation or failure in the orientation during cutting. Thus, a total of 46 premolars and 14 incisors were available for histologic analysis. The results of the histologic measurements are shown in Table I. Three-week experiment. One monkey was killed after 3 weeks of experiment. Around the teeth treated only by surgical intervention and not subjected to either intrusion or hygiene, no significant change in the level of attachment or bone could be detected, although a single tooth demonstrated severe loss of attachment and bone loss. Around the teeth subjected to intrusion, the healing that followed the surgical procedure was complete and the initial reaction to the orthodontic forces could be observed. The supraalveolar fibers were stretched across the marginal bone into the periodontal ligament. On the hygiene side, the notch was always located below the level of the marginal bone. The junctional epithelium was terminated in the coronal third of the
The control teeth that had been subjected only to the surgical treatment (followed by neither a hygiene regimen nor orthodontic treatment) showed the same results as they did following 3 weeks of observation. When observing the teeth subjected to intrusion, the clinical crowns on the hygiene side were shortened and the gingiva adapted closely to the teeth; only physiologic pockets could be measured. Histologically, the peridontium of teeth that had been subjected to intrusion also was clearly influenced by the treatment. The reference notch was situated 0.76 to 2.35 (x = 1.5) mm apical to the level of the apical limitation of the junctional epithelium (Table I). The notch area was lined with a layer of cellular cementum and stretched from the notch in a coronal direction (Figs. 6 and 7). The position of the notch on both the mesial and the distal aspects of the roots clearly demonstrated the previous horizontal bone loss. The epithelial junction was localized very close to the marginal bone level, slightly above in some cases and slightly below in others. Collagen fibers stretched from bone, the periodontal ligament in an apical direction inserting in the cellular cementum of the root surface. The bone surface bordering the periodontal ligament was lined with formative cells (Fig. 8) apart from the apical one fourth in which the ligament appeared to be compressed. No active root resorption could be detected, but apjcally some resorption lacunae that had undergone repair was observed. In the cases in which only one of the neighboring premolars was intruded, there was a distinct difference in the level of connective tissue attachment of the intruded and the nonintruded teeth. In the latter the periodontal treatment had led to new cementum formation
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New attachment through periodontal treatment and orthodontic intrusion
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Flog. 6 (Cont’d). 6, The notch (A) localized below the bony margin (8). New cellular (C) cementum is stretching from the notch coronally toward the epithelial junction (0). It can be seen that the formation 01 new cellular cementum following the scaling starts apically to the notch (0). C, Larger magnification of the notch in 6. Note the repair with cellular cementum (A).
covering the apical half of the notch (Fig. 9). In the intruded teeth the attachment level was in all cases more than 0.7 mm coronal to the apical limitation of the notch. In some sections the translatory movement in the apical direction could be ascertained through the presence of a notch below the marginal bone both mesially and distally (Fig. 9). The amount of intrusion could be measured as the vertical distance between the notches of the two adjacent teeth. Among the incisors the intrusion had in some cases led to an almost complete gingival coverage of the crown. This led to a pseudo-pocket in relation to which
the inflammation could not be controlled (Fig. 10). In these cases a long epithelial attachment was stretched far below the level of the marginal bone. On the nonhygiene side, the teeth had also been intruded, but demonstrated a second degree of looseness; with pockets of 3 to 4 mm, no new attachment could be detected in relation to the notch (Fig. 11). On the nonhygiene side, the level of attachment did not differ significantly from that of the 3-week experiment without hygiene (Fig. 12). The notch was still partly lined with junctional epithelium and the bone level was in some cases localized slightly apical to the notch. The measurements from the gingival margin to
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Ffg. 7. A, Histologic section of a tooth subjected to 4 months of intrusion and hygiene program following a flap operation. Note the position of the notch (A) below the level of bone (6) and junctional epithelium (C). B, Larger magnification of A showing more clearly the new attachment between the apical limit of the notch and the level of the junctional epithelium. Note new cellular cementum of the notch (0) coronally to the junctional epithelium (C).
the epithelial junction showed that no connective tissue attachment had been obtained, nor had any reduction in the pocket depth taken place. In some of the incisors, the intrusion had led to a destruction of the periodontal ligament and in some cases even to complete loss of the buccal cortical lamella since the teeth were tipped labially. The analysis of variance carried out on the data from the nonintruded teeth showed a significant effect of time and/or hygiene (Table IIA) . The significance was, however, even more pronounced in the group of teeth subjected to intrusion (Table IIB).
The three-way analysis of variance (Table III) demonstrated clearly that both hygiene and intrusion were factors of major significance for the explanation of the results. It was also obvious that a significant interaction existed between the two. Time per se did, on the other hand, play only a minor role.
The ability to consistently obtain by orthodontic treatment new attachments on periodontally involved teeth suffering from horizontal bone loss has been a maaer of de,,ate~3,7,9,12,17.27-29
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New attachment through periodontal treatment and orthodontic intrusion 113
Since histologic examination is the only reliable way to ascertain the level of the epithelial junction, experimental studies of attachment are, with few exceptions,29 limited to animal models. The present study was carried out on monkeys previously used as models for research on treatment of human subjects.20*21~23~U~27 The same is true of the dog model.*~** The present study has clearly shown that new connective tissue attachment can be formed during the intrusion of the periodontally involved teeth if the gingival infection is eliminated and the root surfaces are scaled to a degree that makes it possible for a new cementum layer to form on the former infected root surface. After 3 weeks the notch was partly lined with epithelium that apparently was replaced during intrusion by connective tissue attachment. In the teeth treated by a flap operation only, the results corroborated those of similar studies.22.23*27A migration of periodontal ligament cells in a coronal direction 0.2 to 0.5 mm into the notch could be detected.** The results of this study conlirmed, as a number of experimental studies have previously shown, that a new attachment could be formed only by periodontal ligament cells26,27since cells derived from gingival connective tissue and &,eo]ar ~ne:!33.29 lack the ability to form new attachment . Fig. 8. Periodontal ligament corresponding to the middle of the root. Note that no osteoclastic activity is present. The collagen The turnover rate of collagen of the periodontal fibers are stretched from bone in an apical direction toward the ligament is under normal circumstances twice that of cementum covering the root. the attached gingiva”s31; the stimulus generated through orthodontic forces gives rise to a dramatic increase in of the periodontal ligament. In this way hyalinization the number of mitoses.32 In this study, the apical diswas probably limited, which may have been of crucial placement of the tooth was apparently not followed by importance for the result since retardation of the intruan apical migration of the epithelium. A possible exsive movements caused by hyalinization may well allow planation may be that the turnover rate of the perithe epithelial downward growth to occur. Application odontal ligament by far exceeded that of the gingiva.33 of calibrated low magnitude stress diminishes the risk In contrast to previous experiments of intmsion,8~“~28 of root resorption’7~35and does not lead to any detrithe teeth in the present study were not tipped into a mental reactions of the pulp tissue, a finding previously vertical defect, but a movement bodily in an apical reported. 36 direction was intended. Thereby, the orthodontic tooth displacement resulted in a stretching of the collagen A number of authors8*“,16,37*39 consider orthodontic fibers in a gingival/apical direction so that cells of the tooth movement contraindicated if major marginal bone periodontal ligament close to the alveolar bone and loss has occurred due to periodontal disease. KesslerJ’ known to be the most active3* were situated most ginwarned that a rapid progression of pocket deepening likely occurs if orthodontic treatment is undertaken in givally during the intrusion. This may have contributed favorably to the competition between junctional epipatients suffering from periodontal disease. thelial cells and the most coronally situated periodontal The findings of the present study significantly ligament cells. The treatment was carried out with light change the role of orthodontics in the treatment of periforces in an a,pical direction, passing closely to the odontally involved patients. The warning against center of resistance of the teeth in order to avoid tipping intrusion2J*40should, however, not be overruled because of teeth as much as possible.33 Thus, the displacement a meticulous oral hygiene and a healthy gingival status obtained aimed at a low stress in the most marginal part are preconditions for the favorable result.
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Fig. 9. A, Histologic sections of two premolar& (X and y). X has been intruded for 3 months. Both teeth have been subjected to a hygiene program. Note the difference in the level of the notches, indicating the amount of intrusion. The level of collagen attachment is clearly different for the two teeth. Arrows denote the notches on both the mesial and distal roots of the intruded tooth (X), which are at the same level below the bone, indicating that no tipping took place. B, Larger magnification. The levels of the epithelial junctions for X and Y are clearly different.
Provided the periodontal treatment leads to a healthy gingival condition and susceptibility is controlled, the results presented lead to the conclusion that if the orthodontic forces are well calibrated, (1) it is possible to intrude teeth with periodontal bone loss, (2) intrusion may lead to a noticeable gain in connective tissue attachment, and (3) regular curettage during treatment is crucial for the treatment result. On this basis the study suggests a new clinical approach for patients suffering from severe bone loss and drifted teeth.
REFERENCES 1. Chasens AI. Indications and contraindications for adult tooth movement. Dent Clin North Am 1972;16:423-37. 2. Ramfjord SP. Root planning and curettage. Int Dent J 1980; 30:93-100. 3. Thilander B. Orthodontic tooth movement in periodontal therapy. In: Lmdhe J, ed. Textbook of clinical periodontology. Copenhagen: Munksgaard, 1984. 4. Zachrisson BU, Alnaes L. Periodontal condition in orthodontitally treated and untreated individuals. I. Loss of attachment, gingival pocket depth and clinical crown height. Angle Orthod 1973;43:402-11.
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5. Zachrisson BU, Alnaes L. Periodontal condition in orthodontially treated and untreated individuals. II. &veolar bone loss: radiographic findings. &gle Grthod 1974;44:48-55. 6. Stemlicht HC. To$ movement in per@dontal disease. Tex Dent J 1959;77:!i-11. 7. Eliasson LA, Hugqson A, Kural J, Siwe H. The effect of orthodontic treatment on periodontal tissues in patients with redvced periodontal support. Eur J Chthod 1982;4:1-9. 8. Ericsson I, Thilander B, I&-&e J, Okamat H. The effect of orthodoutic tilting movements on the p&iodontal tissues of infected and noninfected gentitions in dogs. J Clin Petiodontol 1977;4:278-93.
9. Ericsson 1, Thilander B. @@dontic relapse in den&ions with reduced pe.Iiodontr$ support. An experimevtal study in dogs. Eur J Chthod 1980;2:52-7. 10. Neusta$ E. The correction of tooth malposition @ a factor in the prevention and treatment of perigontal disease. NY J Dent 1931.1.14-“3. ,. 1, 11. Stem I. To&h malpositions and periodontal pathosis: an evaluation of etisology and considerations in treatment. J Periodontol 1958;29:253-61. 12. Brown IS. l%e effect of orthodontic ther?py on certain types of periodontal defects. Clinical findings. J Periodontol 1973;4: 742-54.
13. Geraci TF. Grt@dontic movement of teeth into artificially produced infrabny defects in the rhesus monkey. A histological report. J Periodontol 1973;44:116. J4. Granems R. Ortodonti och bettrehabilitering. In: Melsen B, ed. Ortodonti NKO. 15-X1-1. Copenhagen: Forlaget for Faglitteratur, 1979. 1.5 Fontenelle A. Le conception parodontale du mouvement dentaire provoque: Evidence cliniques. Rev Grthop Dento Faciale 1982;1:37-5~3. 16. Lemon RR. Simplified root extrusion technique. oral Surg Oral Med Oral Path01 1982;54:93-9. 17. Melsen B. Tissue reaction following application of extrusive and intrusive forces to teeth in adult monkeys. AM J ORTHOD 1986;89:469-75. 18. Patur B, Clickman I. Clinical and roentgenographic evaluation of the postttaatment healing of infrabony pockets. J Periodontol 1962;33: 164-76. 19. Rosling B, Nyman S, Lindhe J. The effect of systematic plaque control of bone regeneration in infrabony pockets. J Clin Periodontol 1976;3:38-53. 20. Caton JG, Zander HA. Primate model for testing periodontal treatment. Procedures: I. Histologic investigation of localized periodontal pockets produced by orthodontic elastics. J Periodontol 1975;46:71-7. a. Polson AM, Heigl LC. Osseous repair in infrabony defects. J Clin Periodontol 1978;5:13-23. 22. Lisgarten MA, Rosenberg MM. Histological study of repair following new ,sttachmentprocedures in human periodontal lesions. J Periodontcl 1979;50:333. 23. Caton JG, Nyman S. l+stometric evaluation of periodontal surgery. I. The modified Widman flap procedure. J Clin Periodontol 1980;7:212-23. 24. Polson A, Caton J, Polson AP, Nyman S, Novak J, Reed B. Periodontal response after tooth movement into infrabony defects. J Periodontol 1984;55: 197-202. 25. Thilander B Orthodontic treatment in dentitions with reduced periodontal support. Rev Belge Med Dent 1982;37:119-25. 26. Nymann S, Kaning T, Bergenholtz G. Bone regeneration in
Fig. 10. Histologic section of a tooth that had been intruded to such an extent that the enamel had been covered by gingiva. The cementoenamel junction (A) is far below the bone margin, whereby a pseudo-pocket has been generated (B). The epithelial junction (C) is localized close to the cementoenamel junction.
27. 28. 29. 30.
31.
32.
alveolar bone dehiscences produced by jiggling forces. J Periodont Res 1982;17:316-22. Gottlow J, Nymann S, Karring T, Lindhe J. New attachment formation as the resu!t of controlled tissue regeneration. J Clin Periodontol 1984;11:494-503. Karring T, Nyman S, Tbilander B, Magnusson I. Bone regeneration in orthodontically produced alveolar bone dehiscences. J Periodont Res 1982;17:309-15. Nyman S, Lindhe J, Karring T, Rylander H. New attachment following surgical treatment of human periodontal disease. J Clin Periodontol 1982b;9:290-6. Sodeck J. A comparison of the rates of synthesis and turnover of collagen and non-collagen proteins in adult rat periodontal tissues and skin used in a microassay. Arch Oral Biol 1977; 22:655-65. Svoboda ELA, Shiga A, Deporter DA. A serologic analysis of collagen phagocytosis by fibroblasts in three soft connective tissues with differing rates of collagen turnover. Anat Ret 1981;199:473-80. Roberts WE, Jee WSS. Cell kinetics of orthodontically stimu-
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Fig. 11. a, Histologic section of two teeth, one of which has been intruded without any hygiene program. Note that the notch of the intruded tooth (A) is almost at the level of the apex of the neighboring tooth (19). No new attachment has occurred. b, Further enlargement of notch in a.
33. 34. 35. 36. 37. 38.
lated and non-stimulated periodontal ligament in the rat. Arch Oral Biol 1974;19:17-21. Roberts WE, Morey ER. Proliferation and differentiation sequence of osteoblast histogenesis under physiological conditions in rat periodontal ligament. Am J Anat 1985;174:105-18. Burstone CJ. Deep bite correction. AM J ORTHOD1977;72:1-22. Reitan K. Effect of force magnitude and direction of tooth movement on different alveolar bone types. Angle Chthod 1964, 34;244. Stenvik A, Mjijr IA. Pulp and dentine reactions to experimental tooth intrusion. AM J ORTHOD1970;57:370-85. biemnann JP. Bone changes related to eruption of the teeth. Angle Drthod 1941;1!:83-99. Moskow B, Karsh F, Stein S. Histological assessmentof autogenous bone graft. J Periodontol 1979;50:291-300.
39. Kessler MBS. Interrelationship between orthodontics and periodontics. AM J CWHOD 1976;70:154-72. 40. Vanarsdall RL, Musich DR. Adult orthodontics: diagnosis and treatment. In: Graber TM, Swain BF, eds. Orthodontics, current principles and techniques. St. Louis: The CV Mosby Company, 1985:791. Reprint
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Dr. Birte Melsen Royal Dental College Institute of Orthodontics DK-8000 Aarhus C Denmark
0 rthodontic treatment of patients with periodontal disease has been a controversial topic. Several authors have cast doubt upon the beneficial effect of such treatment1-3 and some have even claimed that it may have a detrimental effect on the periodontium.4” Others, however, have demonstrated in clinical trkU7 and animal experiments’s9 that orthodontic treatment does not enhance gingival inflammation or marginal bone loss and can have a beneficial effect on the periodontal conditions.‘@13 Hitherto, this has been ascribed to an indirect effect of improved oral hygiene possibilities, better gingival shape, and more suitable distribution of occlusal forces. Extrusion has been used in the reshaping of the alveolar process’4-‘6and extrusion followed by intrusion has demonstrated that part of the bone apposition during extrusion can be maintained From the Royal Dental Cokge, Institute of Orthodontics. *University of Aarhus, Institute of Statistics.
104
during subsequent intrusion, provided healthy gingival conditions are maintained during treatment. l7 Several therapeutic procedures have been suggested to accelerate repair of periodontal angular bony defects’*.‘9 but without changing the level of connective tissue attachment.a*3 On the other hand, orthodontic movement of teeth into infrabony defects has been reported to result in new connective tissue attachment.13 However, other authors performing similar experiments have failed to find support for this statement. In experiments with dogs, Ericsson’ tilted molars into intrabony defects and did not find any evidence of new connective tissue attachment. Polson and associate? by means of the same method also were unable to detect any change of the attachment level. It was common in the above-mentioned experiments for the model used to include a tipping movement, with the highest stress distribution in the marginal part of the periodontal ligament.
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New attachment through periodontal
Fig. 1. A and B, Radiographs demonstrating the marginal bone loss in the lower (A) and upper(B) jaws. C, Intraoral photograph taken during the flap operation. A clear bifurcation involvement is seen.
Since a stress distribution in the periodontal ligament seems highly related to the tissue reaction occurring during orthodontic treatment, tipping cannot be compared directly with a controlled intrusion. A bodily intrusion of periodontally involved teeth suffering from horizontal bone loss thus has not been studied. The present study was carried out with the purpose of comparing the tissue reaction following a flap operatior?’ with and without intrusion, and further to analyze the influence of a hygiene regimen on the results. MATERIAL
AND METHODS
Four adult (15-year-old) female and two male (12were used in year-old) monkeys (A4ucuca fusciculuris) the study. At the start of the experiment, the animals showed signs of gingivitis, but no pockets or loss of attachment could be detected. Intraoral radiographs showed a normal level of supporting alveolar bone. Orthodontic elastic ligatures were placed around premolars and maxillary incisors to produce breakdown of the supporting tissues. 23 A new ligature was placed on top of the other every second week for a period of 3 to 4 months, producing a minimum of 4-mm deep pockets. Intraoral radiographs were taken and showed a mini-
treatment and orthodontic
intrusion
105
Fig. 2. Schematic drawing illustrating the measurements taken. AM-& The distance from the apical limitation of the reference notch to the marginal bone level. AM-GM, The distance from the apical limitation of the notch to the gingival margin. AM-EJ, The distance from apical limitation of the notch to the epithelial junction.
mum of 2-mm marginal bone loss and bifurcation involvement when the first phase of the experiment was concluded (Fig. 1, A and B). The pathologically deepened periodontal pockets were treated by a reverse bevel flap operation.23 The root surface was thoroughly scaled and the granulation tissue was carefully removed from the bony margin without any contouring of the bony edges. During the surgical procedure, a reference notch was prepared with a no. 2 round burr into the mesial and distal surfaces of all experimental teeth, just coronal to the margin of the alveolar bone at the most apical part of the epithelial junction. The notch served as a reference (AM) for the measurements made in the histologic sections (Fig. 2). Following the surgical procedure, the right side of the jaws was subjected to an oral hygiene regimen three times a week including meticulous cleansing with a toothbrush soaked in 0.2% chlorhexidine digluconate solution. One week after surgical treatment, an orthodontic appliance was inserted in both jaws. The three molars
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Dentofac. Orthop. August 1988
Flg. 3. A, Example of an appliance used for intrusion of two premolars in the nonhygiene side. Note the bleeding on probing. B, Intraoral photograph demonstrating the situation after 3 months of intrusion of one lower premolar on the hygiene side. C, Three months of intrusion. No pockets could be measured clinically around the teeth.
of each segment were fitted with a cast metal splint with double rectangular tubes (0.018 x 0.022 inch) soldered buccally and lingually at the level of the second molar. To the upper incisors, small brackets were bonded and a segment of 0.021 x 0.025inch stainless steel wire was adapted to fit the four incisor brackets passively. In three of the monkeys, the two premolars of each segment were connected by bonding a small piece of multistranded wire to the occlusal surfaces (Fig. 3). In the lower jaw, a piece of 0.018-inch TMA* wire was given a U-formed shape and the legs of the U entered the tubes of the molar splint. The round end of the U touched the occlusal surface of the connected premolars with a force of 20 g (Fig. 3). In the upper jaw, a J-shaped 0.017 x 0.025inch TMA wire was placed in the lingual tube with the round end overriding *0rrnw
Corp.,
Glendora,
Calif.
the premolar segment, again with a force of 20 g. In the remaining two monkeys, only one premolar in each segment was intruded (Fig. 4, A and B); the other served as control. For intrusion of the incisors, a base arch was fitted to the buccal tubes of the upper jaw and adapted to intrude the four upper incisors as a segment with a total force of 40 g measured at the midline, the point of force application being lateral to the lateral teeth. The time of intrusion before killing the animals varied from 3 weeks to 3 and 4 months. The monkeys were killed by means of perfusion with 10% buffered formalin. After the animals were killed, the jaws were excised and placed in fixture. Tissue blocks were then cut out and decalcified in EDTA, dehydrated, and double embedded in paraffin celloidin. Serial sections of 8-km thickness were cut mesiodistally through each tooth segment and the section stained alternatively with he-
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New attachment through periodontal treatment and orthodontic intrusion 107
Fhg. 4. A, Histologic section of premolar following intrusion and hygiene regimen 3 weeks postoperatively. It can be seen that the reference notch (A) is localized below the level of marginal bone (B), that the epithelial junction is at the level of marginal bone (C), and that the cementum is subject to osteoclastic activity (0). Bony island (E) probably cut out during the preparation of the notch is subject to remodeling. B, Same as A in a larger magnification. D and E correspond to D and E in A.
matoxylin and eosin, and van Gieson’s connective tissue stains. The following measurements were carried out in the histologic sections (Fig. 2): 1. The distance from AM (the apical limit of the root note h) to the bone level (AM-BL) . The measurements were considered positive if the bone level was located above the marking. 2. The distance from the level of the gingival margin to the apical limit of the root notch in the approximal surface (AM-GM). The measure-
ments were considered to be positive when the gingival level was placed coronal to the marking. 3. The distance between the most apical part of the junctional epithelium (AM-EJ) and the most apical part of the notch. The measurements were considered positive when the junctional epithelium was coronal to the marking. The last measurements were performed with polarized light, making it possible to follow the course of the collagen fibers.
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Dentofac.
Table I. Distance in millimeters between reference points in the various groups (for abbreviations, see Fig. 2) Orthodontic treatment
Perioireatment
Time 3 weeks
Without
Without
intrusion
\
With
Without
With
hygiene
hygiene
hygiene
intrusion
With
hygiene
I I II I
12-16
weeks
3 weeks
12-16
weeks
3 weeks
12-16 weeks
3 weeks
12 weeks
Variable
N
x
SD
Min
MaX
AM-BL AM-GM AM-U AM-BL AM-GM AM-EJ
4
-0.0
6
2.1 0.0 0.1 1.7 -0.1
0.15 1.12 0.1+ 0.50 0.48 0.67
-0.26 0.58 -0.23 1.85 0.61 -1.85
0.27 3.08 0.23 0.38 2.81 1.08
AM-BL AM-GM AM-EJ AM-BL AM-GM AM-EJ
2
0.5 1.0 0.3 0.4 2.1 0.3
0.96 0.37 0.17 0.21 -0.37 0.32
0.42 1.65 -0.12 0.08 1.65 -0.23
0.58 2.23 0.19 0.73 0.23 0.73
AM-BL AM-GM AM-EJ AM-BL AM-GM AM-EJ
4
0.1 2.0 0.2 0.3 2.8 0.9
0.49 1.13 0.22 0.28 0.94 0.75
-0.54 1.15 0.04 0 1.35 0.12
0.77 3.81 0.58 0.85 4.62 2.09
0.8 3.1 0.5 1.3 3.7 1.5
0.21 0.35 0.19 0.29 0.99 0.76
0.58 2.69 0.42 0.77 2.00 0.70
1.00 3.31 0.77 2.23 5.77 2.35
AM-BL AM-GM AM-EJ AM-BL AM-GM AM-EJ
8
10
2
24
table IIA. Analysis of variance-Intra-
and intergroup variation in attachment level (AM-EJ) (measured in millimeters) on the nonintruded teeth (F value reflects the importance of hygiene) Source
Between
groups
within groups TOTAL
DF 3
11 20
Sum of squares 8.3309 11.4717 19.8026
Mean
squares
2.7770 0.6748
F ratio 4.115
P 0.0230
Table 119. Analysis of variance-Intra-
and intergroup variation in attachment level (AM-EJ) (measured in millimeters) on the intruded teeth (F value reflects the importance of hygiene) Source
DF
Between groups Within groups TOTAL
35 38
3
Sum of squares 72.511 23.196 95.707
STATISTICS
A statistical description of the parameters measured was carried out, followed by a comparison of group means by Student’s t test (Table I). An analysis of variance was used to compare intra- and intergroup
Mean
squares
24.170 0.663
F ratio 36.470
P 0.001
variances within the nonintruded teeth (Table IIA), and within the teeth subjected to intrusion (Table IIB). Finally, a three-way analysis of variance was applied for the evaluation of the weight given to each of the factors involved: time, hygiene, and intrusion (Table III).
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2
treatment and orthodontic
intrusion
Fig. 5. a, Histological section of premolar intruded for 3 weeks but without any hygiene control. The epithelial junction (A) is clearly in the apical part of the reference notch. The marginal bone level fs) is below the reference notch. b, Larger magnification of reference notch in a.
Table ! IlIt . II nportance of hygiene, intrusion, and time, and the interactions on the level of attache lent the distanIce frc3rn
Sumof Source of variation Main effects Hygiene (variable 6) Intrusion (variable 7) Time (variable 8) 2-way interactions Variable 6, variable 7 Variable 6, variable 8 Variable 7, variable 8
119.130 28.089 60.130 0.748 10.297 4.322 2.031 0.707
Explained Residual
129.428 35.462 164.890
TOTAL
*While
squares
hygiene
and intrusion
per se are of significance
DF
6 53 55 (p = 0.001).
Mean square
Significance F
ofF
39.710 28.089 60.130 0.748 3.432 4.322 2.031 0.707
59.349 41.981 89.868 1.118 5.130 6.460 3.036 1.057
0.001 0.001 0.001 0.295 0.003 0.014 0.087 0.309
21.571 0.669 2.795
32.239
0.001
time was of significance
only
in interaction
with hygiene.
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August 1988
notch. Below this level clear odontoclasts could be detected, indicating resorption (Fig. 4). On the nonhygiene side, the notch was located just coronal to the bone level; the epithelial junction was localized at the apical border of the notch and osteoelastic activity of the marginal bone could be detected (Fig. 5). At the 3-week experiment, there was already a significant difference in the level of the epithelial junction in relation to the notch between the hygiene and nonhygiene groups. Three- to four-month
experiment (Figs. 6 and 7).
Two monkeys were killed after 3 months and two after 4 months of experimentation. Since no significant difference could be verified between the 3- and 4-month experiments, the data obtained from these animals were pOOled.
Fig. 6. A Histologic section of a tooth that has been subject to 3 m,on@ of intrusion and regular hygiene program. The apical root resorption (A) is only moderate.
RE$lJLTS
Twelve teeth were lost due to exfoliation or failure in the orientation during cutting. Thus, a total of 46 premolars and 14 incisors were available for histologic analysis. The results of the histologic measurements are shown in Table I. Three-week experiment. One monkey was killed after 3 weeks of experiment. Around the teeth treated only by surgical intervention and not subjected to either intrusion or hygiene, no significant change in the level of attachment or bone could be detected, although a single tooth demonstrated severe loss of attachment and bone loss. Around the teeth subjected to intrusion, the healing that followed the surgical procedure was complete and the initial reaction to the orthodontic forces could be observed. The supraalveolar fibers were stretched across the marginal bone into the periodontal ligament. On the hygiene side, the notch was always located below the level of the marginal bone. The junctional epithelium was terminated in the coronal third of the
The control teeth that had been subjected only to the surgical treatment (followed by neither a hygiene regimen nor orthodontic treatment) showed the same results as they did following 3 weeks of observation. When observing the teeth subjected to intrusion, the clinical crowns on the hygiene side were shortened and the gingiva adapted closely to the teeth; only physiologic pockets could be measured. Histologically, the peridontium of teeth that had been subjected to intrusion also was clearly influenced by the treatment. The reference notch was situated 0.76 to 2.35 (x = 1.5) mm apical to the level of the apical limitation of the junctional epithelium (Table I). The notch area was lined with a layer of cellular cementum and stretched from the notch in a coronal direction (Figs. 6 and 7). The position of the notch on both the mesial and the distal aspects of the roots clearly demonstrated the previous horizontal bone loss. The epithelial junction was localized very close to the marginal bone level, slightly above in some cases and slightly below in others. Collagen fibers stretched from bone, the periodontal ligament in an apical direction inserting in the cellular cementum of the root surface. The bone surface bordering the periodontal ligament was lined with formative cells (Fig. 8) apart from the apical one fourth in which the ligament appeared to be compressed. No active root resorption could be detected, but apjcally some resorption lacunae that had undergone repair was observed. In the cases in which only one of the neighboring premolars was intruded, there was a distinct difference in the level of connective tissue attachment of the intruded and the nonintruded teeth. In the latter the periodontal treatment had led to new cementum formation
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Flog. 6 (Cont’d). 6, The notch (A) localized below the bony margin (8). New cellular (C) cementum is stretching from the notch coronally toward the epithelial junction (0). It can be seen that the formation 01 new cellular cementum following the scaling starts apically to the notch (0). C, Larger magnification of the notch in 6. Note the repair with cellular cementum (A).
covering the apical half of the notch (Fig. 9). In the intruded teeth the attachment level was in all cases more than 0.7 mm coronal to the apical limitation of the notch. In some sections the translatory movement in the apical direction could be ascertained through the presence of a notch below the marginal bone both mesially and distally (Fig. 9). The amount of intrusion could be measured as the vertical distance between the notches of the two adjacent teeth. Among the incisors the intrusion had in some cases led to an almost complete gingival coverage of the crown. This led to a pseudo-pocket in relation to which
the inflammation could not be controlled (Fig. 10). In these cases a long epithelial attachment was stretched far below the level of the marginal bone. On the nonhygiene side, the teeth had also been intruded, but demonstrated a second degree of looseness; with pockets of 3 to 4 mm, no new attachment could be detected in relation to the notch (Fig. 11). On the nonhygiene side, the level of attachment did not differ significantly from that of the 3-week experiment without hygiene (Fig. 12). The notch was still partly lined with junctional epithelium and the bone level was in some cases localized slightly apical to the notch. The measurements from the gingival margin to
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Dentofac. Orthop. August 1988
Ffg. 7. A, Histologic section of a tooth subjected to 4 months of intrusion and hygiene program following a flap operation. Note the position of the notch (A) below the level of bone (6) and junctional epithelium (C). B, Larger magnification of A showing more clearly the new attachment between the apical limit of the notch and the level of the junctional epithelium. Note new cellular cementum of the notch (0) coronally to the junctional epithelium (C).
the epithelial junction showed that no connective tissue attachment had been obtained, nor had any reduction in the pocket depth taken place. In some of the incisors, the intrusion had led to a destruction of the periodontal ligament and in some cases even to complete loss of the buccal cortical lamella since the teeth were tipped labially. The analysis of variance carried out on the data from the nonintruded teeth showed a significant effect of time and/or hygiene (Table IIA) . The significance was, however, even more pronounced in the group of teeth subjected to intrusion (Table IIB).
The three-way analysis of variance (Table III) demonstrated clearly that both hygiene and intrusion were factors of major significance for the explanation of the results. It was also obvious that a significant interaction existed between the two. Time per se did, on the other hand, play only a minor role.
The ability to consistently obtain by orthodontic treatment new attachments on periodontally involved teeth suffering from horizontal bone loss has been a maaer of de,,ate~3,7,9,12,17.27-29
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New attachment through periodontal treatment and orthodontic intrusion 113
Since histologic examination is the only reliable way to ascertain the level of the epithelial junction, experimental studies of attachment are, with few exceptions,29 limited to animal models. The present study was carried out on monkeys previously used as models for research on treatment of human subjects.20*21~23~U~27 The same is true of the dog model.*~** The present study has clearly shown that new connective tissue attachment can be formed during the intrusion of the periodontally involved teeth if the gingival infection is eliminated and the root surfaces are scaled to a degree that makes it possible for a new cementum layer to form on the former infected root surface. After 3 weeks the notch was partly lined with epithelium that apparently was replaced during intrusion by connective tissue attachment. In the teeth treated by a flap operation only, the results corroborated those of similar studies.22.23*27A migration of periodontal ligament cells in a coronal direction 0.2 to 0.5 mm into the notch could be detected.** The results of this study conlirmed, as a number of experimental studies have previously shown, that a new attachment could be formed only by periodontal ligament cells26,27since cells derived from gingival connective tissue and &,eo]ar ~ne:!33.29 lack the ability to form new attachment . Fig. 8. Periodontal ligament corresponding to the middle of the root. Note that no osteoclastic activity is present. The collagen The turnover rate of collagen of the periodontal fibers are stretched from bone in an apical direction toward the ligament is under normal circumstances twice that of cementum covering the root. the attached gingiva”s31; the stimulus generated through orthodontic forces gives rise to a dramatic increase in of the periodontal ligament. In this way hyalinization the number of mitoses.32 In this study, the apical diswas probably limited, which may have been of crucial placement of the tooth was apparently not followed by importance for the result since retardation of the intruan apical migration of the epithelium. A possible exsive movements caused by hyalinization may well allow planation may be that the turnover rate of the perithe epithelial downward growth to occur. Application odontal ligament by far exceeded that of the gingiva.33 of calibrated low magnitude stress diminishes the risk In contrast to previous experiments of intmsion,8~“~28 of root resorption’7~35and does not lead to any detrithe teeth in the present study were not tipped into a mental reactions of the pulp tissue, a finding previously vertical defect, but a movement bodily in an apical reported. 36 direction was intended. Thereby, the orthodontic tooth displacement resulted in a stretching of the collagen A number of authors8*“,16,37*39 consider orthodontic fibers in a gingival/apical direction so that cells of the tooth movement contraindicated if major marginal bone periodontal ligament close to the alveolar bone and loss has occurred due to periodontal disease. KesslerJ’ known to be the most active3* were situated most ginwarned that a rapid progression of pocket deepening likely occurs if orthodontic treatment is undertaken in givally during the intrusion. This may have contributed favorably to the competition between junctional epipatients suffering from periodontal disease. thelial cells and the most coronally situated periodontal The findings of the present study significantly ligament cells. The treatment was carried out with light change the role of orthodontics in the treatment of periforces in an a,pical direction, passing closely to the odontally involved patients. The warning against center of resistance of the teeth in order to avoid tipping intrusion2J*40should, however, not be overruled because of teeth as much as possible.33 Thus, the displacement a meticulous oral hygiene and a healthy gingival status obtained aimed at a low stress in the most marginal part are preconditions for the favorable result.
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Fig. 9. A, Histologic sections of two premolar& (X and y). X has been intruded for 3 months. Both teeth have been subjected to a hygiene program. Note the difference in the level of the notches, indicating the amount of intrusion. The level of collagen attachment is clearly different for the two teeth. Arrows denote the notches on both the mesial and distal roots of the intruded tooth (X), which are at the same level below the bone, indicating that no tipping took place. B, Larger magnification. The levels of the epithelial junctions for X and Y are clearly different.
Provided the periodontal treatment leads to a healthy gingival condition and susceptibility is controlled, the results presented lead to the conclusion that if the orthodontic forces are well calibrated, (1) it is possible to intrude teeth with periodontal bone loss, (2) intrusion may lead to a noticeable gain in connective tissue attachment, and (3) regular curettage during treatment is crucial for the treatment result. On this basis the study suggests a new clinical approach for patients suffering from severe bone loss and drifted teeth.
REFERENCES 1. Chasens AI. Indications and contraindications for adult tooth movement. Dent Clin North Am 1972;16:423-37. 2. Ramfjord SP. Root planning and curettage. Int Dent J 1980; 30:93-100. 3. Thilander B. Orthodontic tooth movement in periodontal therapy. In: Lmdhe J, ed. Textbook of clinical periodontology. Copenhagen: Munksgaard, 1984. 4. Zachrisson BU, Alnaes L. Periodontal condition in orthodontitally treated and untreated individuals. I. Loss of attachment, gingival pocket depth and clinical crown height. Angle Orthod 1973;43:402-11.
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5. Zachrisson BU, Alnaes L. Periodontal condition in orthodontially treated and untreated individuals. II. &veolar bone loss: radiographic findings. &gle Grthod 1974;44:48-55. 6. Stemlicht HC. To$ movement in per@dontal disease. Tex Dent J 1959;77:!i-11. 7. Eliasson LA, Hugqson A, Kural J, Siwe H. The effect of orthodontic treatment on periodontal tissues in patients with redvced periodontal support. Eur J Chthod 1982;4:1-9. 8. Ericsson I, Thilander B, I&-&e J, Okamat H. The effect of orthodoutic tilting movements on the p&iodontal tissues of infected and noninfected gentitions in dogs. J Clin Petiodontol 1977;4:278-93.
9. Ericsson 1, Thilander B. @@dontic relapse in den&ions with reduced pe.Iiodontr$ support. An experimevtal study in dogs. Eur J Chthod 1980;2:52-7. 10. Neusta$ E. The correction of tooth malposition @ a factor in the prevention and treatment of perigontal disease. NY J Dent 1931.1.14-“3. ,. 1, 11. Stem I. To&h malpositions and periodontal pathosis: an evaluation of etisology and considerations in treatment. J Periodontol 1958;29:253-61. 12. Brown IS. l%e effect of orthodontic ther?py on certain types of periodontal defects. Clinical findings. J Periodontol 1973;4: 742-54.
13. Geraci TF. Grt@dontic movement of teeth into artificially produced infrabny defects in the rhesus monkey. A histological report. J Periodontol 1973;44:116. J4. Granems R. Ortodonti och bettrehabilitering. In: Melsen B, ed. Ortodonti NKO. 15-X1-1. Copenhagen: Forlaget for Faglitteratur, 1979. 1.5 Fontenelle A. Le conception parodontale du mouvement dentaire provoque: Evidence cliniques. Rev Grthop Dento Faciale 1982;1:37-5~3. 16. Lemon RR. Simplified root extrusion technique. oral Surg Oral Med Oral Path01 1982;54:93-9. 17. Melsen B. Tissue reaction following application of extrusive and intrusive forces to teeth in adult monkeys. AM J ORTHOD 1986;89:469-75. 18. Patur B, Clickman I. Clinical and roentgenographic evaluation of the postttaatment healing of infrabony pockets. J Periodontol 1962;33: 164-76. 19. Rosling B, Nyman S, Lindhe J. The effect of systematic plaque control of bone regeneration in infrabony pockets. J Clin Periodontol 1976;3:38-53. 20. Caton JG, Zander HA. Primate model for testing periodontal treatment. Procedures: I. Histologic investigation of localized periodontal pockets produced by orthodontic elastics. J Periodontol 1975;46:71-7. a. Polson AM, Heigl LC. Osseous repair in infrabony defects. J Clin Periodontol 1978;5:13-23. 22. Lisgarten MA, Rosenberg MM. Histological study of repair following new ,sttachmentprocedures in human periodontal lesions. J Periodontcl 1979;50:333. 23. Caton JG, Nyman S. l+stometric evaluation of periodontal surgery. I. The modified Widman flap procedure. J Clin Periodontol 1980;7:212-23. 24. Polson A, Caton J, Polson AP, Nyman S, Novak J, Reed B. Periodontal response after tooth movement into infrabony defects. J Periodontol 1984;55: 197-202. 25. Thilander B Orthodontic treatment in dentitions with reduced periodontal support. Rev Belge Med Dent 1982;37:119-25. 26. Nymann S, Kaning T, Bergenholtz G. Bone regeneration in
Fig. 10. Histologic section of a tooth that had been intruded to such an extent that the enamel had been covered by gingiva. The cementoenamel junction (A) is far below the bone margin, whereby a pseudo-pocket has been generated (B). The epithelial junction (C) is localized close to the cementoenamel junction.
27. 28. 29. 30.
31.
32.
alveolar bone dehiscences produced by jiggling forces. J Periodont Res 1982;17:316-22. Gottlow J, Nymann S, Karring T, Lindhe J. New attachment formation as the resu!t of controlled tissue regeneration. J Clin Periodontol 1984;11:494-503. Karring T, Nyman S, Tbilander B, Magnusson I. Bone regeneration in orthodontically produced alveolar bone dehiscences. J Periodont Res 1982;17:309-15. Nyman S, Lindhe J, Karring T, Rylander H. New attachment following surgical treatment of human periodontal disease. J Clin Periodontol 1982b;9:290-6. Sodeck J. A comparison of the rates of synthesis and turnover of collagen and non-collagen proteins in adult rat periodontal tissues and skin used in a microassay. Arch Oral Biol 1977; 22:655-65. Svoboda ELA, Shiga A, Deporter DA. A serologic analysis of collagen phagocytosis by fibroblasts in three soft connective tissues with differing rates of collagen turnover. Anat Ret 1981;199:473-80. Roberts WE, Jee WSS. Cell kinetics of orthodontically stimu-
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Fig. 11. a, Histologic section of two teeth, one of which has been intruded without any hygiene program. Note that the notch of the intruded tooth (A) is almost at the level of the apex of the neighboring tooth (19). No new attachment has occurred. b, Further enlargement of notch in a.
33. 34. 35. 36. 37. 38.
lated and non-stimulated periodontal ligament in the rat. Arch Oral Biol 1974;19:17-21. Roberts WE, Morey ER. Proliferation and differentiation sequence of osteoblast histogenesis under physiological conditions in rat periodontal ligament. Am J Anat 1985;174:105-18. Burstone CJ. Deep bite correction. AM J ORTHOD1977;72:1-22. Reitan K. Effect of force magnitude and direction of tooth movement on different alveolar bone types. Angle Chthod 1964, 34;244. Stenvik A, Mjijr IA. Pulp and dentine reactions to experimental tooth intrusion. AM J ORTHOD1970;57:370-85. biemnann JP. Bone changes related to eruption of the teeth. Angle Drthod 1941;1!:83-99. Moskow B, Karsh F, Stein S. Histological assessmentof autogenous bone graft. J Periodontol 1979;50:291-300.
39. Kessler MBS. Interrelationship between orthodontics and periodontics. AM J CWHOD 1976;70:154-72. 40. Vanarsdall RL, Musich DR. Adult orthodontics: diagnosis and treatment. In: Graber TM, Swain BF, eds. Orthodontics, current principles and techniques. St. Louis: The CV Mosby Company, 1985:791. Reprint
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to:
Dr. Birte Melsen Royal Dental College Institute of Orthodontics DK-8000 Aarhus C Denmark