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Maxillary canine retraction, periodontal surgery, and relapse
Maxillary canine retraction, periodontal surgery, and relapse Antony G. H. McCollum and Charles Brian Preston Johannesburg,
Republic of South Africu
Extraction spaces closed during the course of orthodontic therapy tend to rr-open. ” ‘. ‘I whereas orthodontically rotated teeth ure prone to relapse. ‘H One of the mujor 1~uust3 (?/ spaces opening between teeth is the supru-alveolar soft tissues which do not ctlways udupt to the new tooth positions. 3, 3, i, 9. lo, 12.‘RSeven patients requiring extra&on of upper.first premolar teeth as part of their orthodontic, treatment were selected for thi,c .studv. Tattoo murks were placed in the uttached gingirwe close to the upper canine teeth. The c~trnine.~ were then retracted orthodontically across the extraction spaces. The left sidll WI.S designated the control side and the right side the experimentul side. Immedintel~ ujier completion of retraction, the attached gingiva was surgically detached from the canine teeth on the experimental sides. The canines on both sides were retuined in their new positions for 8 weeks following spuce closure. The amount of relapse or recoil of the gingivae was measured. In this study the gross gingival changes were similar to those described by Atherton and Kerr,” Atherton, 25Edwards.’ The tuttoo marks moved distullj with the retructed canines. The umount of gingival movement MUS similar on both experimental und control sides and ranged between 49.4 percent and 82.4 percent of the retraction distance. Very little recoil or relapse of the gingivae nccurretl,fi,llowing surgicul detuchment from the canines. The results of this study indicate thut the gingi\‘ae appear to udapt to the new tooth position und that relapse qf cunines retructed across extraction sites in the maxilla is not necessarily caused by the supra-czhleolur soft ti.ssues. Key words:
Canines, retraction,
periodontal
surgery, relapse
T
he extraction of teeth may be required in orthodontic treatment to satisfy the demands made by function, esthetics, and stability.’ Notwithstanding attention to detail during treatment, certain undesirable changes are seen during and after retention. Spaces may open between teeth approximated at extraction sites, 2* 3 while derotated teeth tend to return to their original positions. 4-6 The elasticity of the supra-alveolar soft tissue is cited by Thompson,4, 7 Reitan,5, 8, s Edwards,2* lo* ‘I and otherG 12, l3 as a major cause of this type of relapse. Connective tissue fibers of the supra-alveolar system join the attached gingivae to the alveolar bone and cementum of the teeth. The dentogingival or A, B, and C groups of fibers14, I5 attach the marginal and attached gingivae to the teeth (Fig. 1, a), while the transseptal fibers originate in the cementum of adjacent teeth in the dental arch and traverse the interdental septa16 (Fig. 1, b). Included in this system are the circular fiberI (Fig. 1, c) and the vertical and horizontal fiber groups” (Fig. 1, d). Fullmer and Lilliels reported oxytalan fibers which have “elastic-like” properties in the connective tissues of human gingivae. EdwardslO noted that in orthodontically rotated 610
0002.9416/80/120610+13$01.30/0
0
1980 The C. V. Mosby CO.
Volume 78 Number 6
Muxilltrry
Fig
Fig
la
DENTOGINGIVAL
Fig
lc
CIRCULAR
lb
TRANSEPTAL
retraction
611
FIBRES
FIBRES
Fig
FIBRES
Id
HORIZONTAL
VERTICAL
Fig.
canine
1. The
supra-alveolar
fiber
and
FIBRES
network.
teeth these fibers were more numerous and more clearly defined than in nonrotated teeth. Parker,3 in a study on ikfacaca rhesus monkeys, found that the oxytalan fibers are associated and intermingled with collagen fibers, particularly those collagen fibers under stress. They were seen to arise from “connective tissue strands” and none were seen to attach to bone, findings which Fullmer and colleagueszO confirm. EdwardslO postulated that a possible function of oxytalan fibers is to prevent overstretching of tissues in stressed areas. Erikson and associateszl concluded that the transseptal fibers have the capacity to separate approximated teeth at extraction sites. Reitan *, s demonstrated graphically that a large proportion of orthodontic relapse may occur within the first 2 hours after removal of an appliance. Since the work of Thompson and co-workers,22 many research workers have also advocated various forms of surgery to relieve the tension in the supra-alveolar fibers following orthodontic movement. 2, 3, 6, 11-13In these studies the authors are concerned with relapse of orthodontically moved teeth following surgery and compare this movement to that of control teeth. Atherton and Kerrz4 and Athertonz5 described the superficial gingival changes that take place during orthodontic retraction of maxillary canine teeth. They placed a small tattoo mark on the buccal aspect of the mesial interdental papilla of the canine being retracted. As the teeth were moved distally, the tattoo mark appeared to be “left behind. ” The gingivae on the distal aspect accumulated until the papillae appeared enlarged with folds or creases extending vertically from them. Edward? associated the presence of these gingival clefts with orthodontic relapse.
Fig.
2. Tattoo
marks
in the attached
gingivae
The purpose of the present study is to describe the gross changes that take place in the gingivae during upper canine retraction across an extraction site, to measure the amount of movement of the gingivae relative to retracted canine teeth, and to determine whether the gingivae adjacent to the orthodontically moved teeth adapt to the new tooth positions or whether they behave in an elastic fashion. Materials and methods Seven patients with Angle Class II, Division 1 malocclusions constituted the sample in the study. They all required the extraction of upper first premolar teeth as part of their orthodontic treatment. Their ages ranged from 12 years to 18 years, and they included three girls and four boys. The patients ’ upper canines, second premolars, and molars were banded and leveled, following which the upper canines were retracted individually. Subsequent to banding, three tattoo spots were placed in the buccal attached gingivae opposite the distal quarter of the canine teeth. They were arranged in a vertical direction 1 to 2 mm. apart (Fig. 2). These tattoo marks were made by introducing sterile India ink into the lamina propria. Retraction of the upper canines was accomplished by using 0.021 by 0.021 inch looped sectional arches which were reduced posteriorly to facilitate activation. Rampton headgear were worn between 8 and 10 hours a day to preserve anchorage of the upper posterior buccal segments. Comparison of the pre- and posttreatment study models in Figs. 3 and 4 shows that the molar relationships were maintained. On completion of canine retraction, the teeth were retained for a period of 8 weeks by means of straight 0.021 by 0.021 inch sectional arches while headgear wear was continued. Lateral cephalometric radiographs were taken of each patient prior to and at the completion of upper canine retraction. These radiographs were traced by independent orthodontists and the tracings were compared. In each instance the pre- and postretraction cephalometric tracings were superimposed on the palatal planes at ANS. The distances from the pterygoid vertical (PTV) to the distal aspect of the upper first molars were also measured and compared (Fig. 7). In all cases, on the basis of cephalometric evidence, it
Volume 78 Number 6
A4axillaiy
canine
retraction
613
Fig. 3. Study models-left side. I, Before canine retraction. II, On completion of canine retraction showing preservation of posterior anchorage.
Fig. 4. Study models-right side. I, Before canine retraction. II, On completion showing preservation of posterior anchorage.
of canine retraction
appears that there was less than 1 mm. of mesial movement of the upper first molars during canine retraction. The gross gingival changes were recorded before, during, and after retraction of the canines, while photographs and study models were taken prior to and after distal retraction of the canine teeth. To study the amount of gingival movement relative to tooth movement, the following measurements were made: 1. “The canine retraction distance” from the distal contact point of the canine to the mesial contact point of the second premolar (Fig. 5, A and Table I, column A). 2. The distance between the most occlusal tattoo mark and the contact point of the upper second premolar, referred to as the “tattoo retraction distance” (Fig. 5, B and Table I, column B). 3. At the end of canine retraction the distance between the most occlusal tattoo mark and the contact point between the upper second premolar and canine teeth was again measured (Fig. 6, C and Table I, column C).
614
MrColltrtn
Table
rvtd
I. Gingival
Presron
movement
relative
to linear
tooth
movement
Pafient
Side
A (mtn.)
B (mm.)
C (mm.)
I) (mm .)
I
Left Right Left Right Left Right Left Right Left Right Left Right Left Right
7.5 8.4 9.1 9.3 1.2 1.5 1.5 1.4 1.4 7.5 7.1 7.4 5.4 5.7
10.9 I I.0 12.0 12.4 6.5 1.5 7.1 1.5 1.4 1.5 8.8 9.0 6.1 6.4
5.3 4.9 6.9 7.2 2.5 3.0 3.7 3.8 3.7 3.X 3.0 2.8 2.4 2.5
5.6 6. I 5.1 5.2 4.0 4.5 4.0 3.7 3.7 3.7 5.8 6.2 3.7 3.9
2 3 4 5 6 7
E (percenr) 74.74 12.6% 56.1% 55.97<> 55.5% 60.0% 53.3% SO.OW 50.0% 49.4% 80.3% 82.48 68.5% 68.7%
F (mtn.) 1.9 2.3 4.0 4.1 3.2 3.0 3.5 3.7 3.7 3.x 1.3 I.2 I .7 I.8
The left side is the control side. The right side is the surgical side. Column A shows the distance from the distal surface of the canine to the mesial surface of the second premolar tooth (the distance over which the canine is retracted). Column B shows the distance between the most occlusal tattoo mark and the mesial aspect of the second premolar tooth prior to canine retraction. Column C shows the distance between the most occlusal tattoo mark and the second premolar after retraction of the canine tooth. Column D shows the total gingival movement, which is Column B minus Column C. Column E shows the percentage of gingival movement relative to the canine, which is Column D -X 7 = Percentage Column A Column F shows which is Column
the gingival “stretch or lag,” A minus Column D.
which
is total tooth
movement
minus
total gingival
movement,
It was possible to calculate gingival movement which resulted from the canine retraction by comparing the positions of tattoo marks prior to and on completion of tooth movement (Table I, column D). It was also possible to express the gingival movement as a percentage of the distance through which the canines were moved (Table I, column E). Gingival Canine
movement
retraction
distance
x loo =
the percentage of gingival movement relative to tooth movement.
All measurements were recorded with the aid of fine-point dividers and a Vernier scale which was graduated in tenths of a millimeter. Five independent measurements were recorded, and the mean of these was calculated and used as the effective value. The next stage of the experiment was designed to examine the stability of the attached gingivae in their new positions. The sample of seven patients was divided into two groups. Group A comprised three patients, and the remaining four patients made up Group B. Both groups were subjected to surgical procedures on their right sides, the left sides remaining for control purposes. Prior to the surgical procedures, retention arches were placed while headgear wear was continued. Group A. The surgical procedure is illustrated in Fig. 8. The surgery followed admin-
Volume 78 Number 6
Maxillury
Fig. 5. Landmarks retraction distance.
measured prior to orthodontic retraction B is the tattoo-retraction distance.
Fig. 6. Landmarks
Table
II. Postsurgical Patient
recoil
measured
on completion
of the
cunine
canine
of canine
teeth.
retraction
A is the
615
canine-
retraction.
or relapse A (mm.)
Side
Left Right Left Right Left Right Group Left Right Left Right Left Right Left Right
Group 5.3 4.9 6.9 1.2 2.5 3.0 B (includes 3.1 3.8 3.1 3.8 3.0 2.8 2.4 2.5
B (mm.)
C (mm.)
5.3 5.3 6.9 1.2 2.5 3.7
0 0.4 0 0 0 0.1
3.1 3.9 3.1 4.0 3.0 3.4 2.4 2.8
0 0.1 0 0.2 0 0.6 0 0.3
A
papillectomy)
The left side is the control side. The right side is the surgical side. Column A shows the distance between the most occlusal tattoo mark and the second premolar after retraction of the canine tooth. Column B shows the distance between the most occlusal tatoo mark and the second premolar after the fiber cuts. Retention appliances were in place to maintain the tooth positions as far as possible. Column C reflects the recoil of the gingivae, which is Column B minus Column A. No measurable recoil was found on the left (experimental) side.
PATIENT
PA",
BEFORE
-
AFTER
--~--
A
Fig. 7. Before- and after-treatment lateral cephalometric ANS.
tracings superimposed
on the palatal plane at
&ration of a local anesthetic and was aimed at detaching the gingivae from the teeth. This surgical procedure is referred to as the circumdental fiber cut. The gingival cleft which resulted from the folding of the gingival tissues during tooth retraction was incised as follows: On the distal side of the canines in the line of the gingival cleft, a vertical incision was made on both the buccal and palatal sides. These were extended to meet in the co1 area of accumulated tissue and approximately in the region of the tooth contact point (Figs. 8 and 9). The vertical incisions on the buccal side extended 2 to 3 mm. into the buccal mucosa. Both the palatal and buccal incisions penetrated through to the periosteum and bone. These vertical incisions were aimed at releasing residual tension or pressure which may have built up in the region of the cleft. Group B. In Group B the same circumdental and vertical incisions were made. In addition, a papillectomy of the accumulated tissue on the distal side of the retracted canines was performed (Fig. 9). Fig. 10 shows the extent of the papillectomy in the vertical plane. The purpose of the procedure was to remove this cuff of tissue which possibly could have prevented the buccal and palatal attached gingivae from relapsing or recoiling. Forty-eight hours after the surgical procedure the relapse or recoil of the gingivae was measured in both Groups A and B. This was done by measuring the distance between the most occlusal tattoo marks and the contact point of canine and second premolar (Fig. 6 and Table II, column B).
l’olumr 78 Number 6
Fig.
Maxillury
8. 7, Circumdental
Fig. 9. 7, Circumdental Papillectomy
incision.
incision. of the accumulated
2, Vertical
incision
2, Vertical incision gingival tissue.
along
along
canine retraction
67 7
the line of the gingival
cleft
or groove.
the
cleft
or groove.
line of the vertical
3,
Findings
Between 4 and 5 months were required to retract the canines. On the experimental as well as the control sides there was a heaping-up of the gingivae on the distal aspect of the teeth being retracted. At maximum canine retraction, when the contact point with the second maxillary premolar was re-established, the accumulated gingivae were seen as grossly enlarged buccal and palatal interdental papillae (Fig. 11). These findings were previously reported by Atherton and Kerr,24 Atherton,25 and Edwards.* The enlarged papillae in both groups appeared to be twice the size of normal papillae. The height of the enlarged papillae was measured to be an average of 4 mm. as against the
Fig.
Fig. 11. An example the retracted canine
10. 7 shows
of the slit or groove tooth.
the vertical
extending
extent
from
of the papillectomy.
the “heaped-up”
tissue
on the distal
aspect
of
preretraction average height of 2 mm. The vertical height was measured between the most apical portion of the gingival margin around the premolar teeth and the apices of the papillae. Extending vertically from the enlarged papillae to the junction of the alveolar mucosa and the attached gingivae, a groove or a slit appeared (Fig. 11). The slit was seen on the buccal and palatal sides and appeared to enter the papillae; however, no tunnel was formed in the buccal and palatal aspects. During distal movement of the retracted canines the “red patch” described by Atherton and Kerr*-’ became evident on the mesial side of the upper canine teeth (Fig. 12). of the This “patch” was triangular in shape, with its base against the mesial surfaces upper canines. The red area was depressed below the level of the surrounding gingivae. The deeper red color of the triangle could be attributed to the thin nature of the epithelium which appeared to be unkeratinized in this sample. After the retention period of 2 months which followed the surgical release of the supra-alveolar fibers, the red patch disappeared on both surgical and control sides. This area, however, still appeared flattened or slightly depressed below the surrounding gingivae. At the onset of canine retraction the adjacent
Volume 78 Number 6
Fig. 12. An example tooth.
hfuxillary canine retraction
of the triangular
depressed
red patch
on the mesial
aspect
of the retracted
619
canine
incisors tended to follow the retracted canines in their distal movements. This resulted in a loss of the previously tight contact points between these teeth (Figs. 10 and 11). The vertical tattoo marks appeared to slope in the direction of canine movement to only a small degree. Gingivul movement. The gingivae marked with the tattoo dots moved distally with the fourteen retracted canines but not in a 1: 1 ratio with these teeth. (Compare A and B in Fig. 13.) The gingival movement is recorded in Table I, column D, and ranged between 3.7 and 6.2 mm. This movement is expressed as a percentage of the canine retraction distance, which ranged between 49.4 and 82.4 percent. The amount of “stretch or lag” relative to the retracted canine teeth is recorded in Table I, column F, and ranged between 1.2 and 4.1 mm. Gingival adaptation. Forty-eight hours after the periodontal surgery in Groups A and B the distance between the second premolar and the most occlusal tattoo mark was recorded (Table II, column B). This distance was compared with the distance between the tattoo mark and the second premolar prior to the surgery (Table II, column A, and Table I, column C). The difference between the two readings (Table II, column C) represents the amount of recoil or relapse of the gingivae that occurred 48 hours after surgery. The recoil ranged between 0 and 0.7 mm. in Group A and 0 and 0.6 mm. in Group B. (Compare Fig. 13, C with Fig. 13, B on the surgical side.) No recoil movement of the gingivae on the control side occurred. Group B had a surgical papillectomy in addition to the periodontal surgery. There was little postsurgical difference in the amount of recoil or relapse between these two groups during the first 48 hours. Following the surgery, the retracted canines became markedly mobile and were rated as being Grade II mobile (according to the rating used by the Department of Periodontics of the University of the Witwatersrand). It appeared that the mobility of the canines was slightly greater, but still Grade II mobile, in Group B where the papillectomy was performed. No pain or discomfort was reported by these patients. The depth of the gingival crevice was measured prior to and after surgery and was not significantly altered by the
Fig. 13. Right side. A, Position of upper canine and tattoo marks prior to distal retraction af these teeth. B, Position of upper canine and tattoo marks on completion of canine retraction. C. Position of tattoo marks 48 hours after periodontal surgery.
Fig. 14. Left side. Position of upper marks
48 hours
A, Position of upper canine and tattoo after
periodontal
canine marks
and tattoo marks prior to distal retraction of these on completion of canine retraction C, Position
teeth. B, of tattoo
surgery.
surgical procedures. At the end of the retention period, during which time the retraction space was maintained, the periodontal situation was again assessed. There was no measurable change in the depths of the gingival crevices during the retention phase. At the same examination no further recoil of the gingivae was demonstrated on either the experimental or the control sides. Discussion The gross changes seen in the gingivae during retraction of the upper canines are similar to those described by Atherton and Kerr,*” Atherton,‘j and Edwards.? By measuring the changes that took place in the position of the gingival tattoos, it was possible to show that the soft tissue of this area moves between 49.4 and 82.4 percent of the tooth movement. EdwardslO found that when teeth were orthodontically rotated the gingivae followed the rotated teeth through the same degree of movement. EdwardslO found this gingival movement to be consistent throughout his studies on rotated teeth. In our study the discrepancy in movement that was noted between the soft tissue and tooth movement could possibly be attributed to one or a combination of factors: (1) the supra-alveolar fibers and gingivae are “elastic” and are “stretched” as the tooth is retracted distally, (2) the supra-alveolar tissues actively adjust themselves to the new tooth positions (which has been refuted by Erikson and associates*’ and Burket*‘j), (3) pathologic tearing of the fibers as suggested by Heuttner.2’ A number of authors have investigated the potential effects of the supra-alveolar fibers
Volume 78 Number 6
Maxillary
canine
retraction
621
in causing relapse of orthodontically moved teeth. In their studies, surgery was performed on the gingivae either before, during, or after a retention period and the teeth were subsequently allowed to relapse. The amount of relapse was measured and compared with relapse seen in control teeth. In the present study a different procedure was used. Immediately on completion of distal retraction of the upper canine teeth, periodontal surgery was performed in order to release the gingivae from these teeth. The canines were held in retention immediately following retraction, and subsequent to the surgical procedure the gingivae were allowed to recoil or relapse on their own. The changes in gingival position were recorded. Our procedure was based on the work performed by Edwards,‘O, l1 who worked on orthodontically derotated teeth. His results appear to indicate that the gingivae do not adapt to new tooth positions but behave in an “elastic-like” manner. In the present study it was shown that the gingivae close to the teeth being moved followed the tooth movement by between 49.4 and 82.4 percent of the retraction distance. In the main, it was thought that the surgical cutting of all the supra-alveolar fibers would release the gingivae from the teeth and would establish whether or not the gingivae adapt to the tooth movement or react in an elastic-like fashion, as suggested by the work of Edwards.‘O, l1 The results of this study indicate that, after surgery, very little recoil of the gingivae occurs. The papillectomy in Group B did not cause the adjacent gingivae to recoil or relapse more than those in Group A. For this reason, we believe that there must be some adaptation of the gingival soft tissue to new tooth positions. This adaptation would reduce, to some extent, the role which the gingival tissues are said to play in orthodontic relapse. This is particularly so when teeth have been approximated at an extraction site. Conclusions 1. The gross gingival changes that take place during distal retraction of upper canine teeth are characterized by an accumulation of gingival tissue on the distal aspects of these teeth. Slits or clefts extend vertically from this accumulated tissue on the palatal and buccal sides, while on the mesial aspects depressed triangular red patches appear. 2. The attached and marginal gingivae adjacent to the upper canine teeth move distally with the retracted canine, but not in a 1: 1 ratio. The gingival soft tissues move distally between 49.4 and 82.4 percent of the canine-retraction distance. In determining these percentages, we have not taken into account anchorage loss. In all of our patients studied the anchorage loss appears to be minimal and to be less than 1 mm. as measured on the cephalometric radiographs. 3. After periodontal surgery which detached the gingivae from the retracted teeth, negligible if any relapse or recoil of the gingivae was seen to occur with our method of measurement.
REFERENCES 1. White, T. C., Gardiner, J. H., and Leighton, B. C.: Orthodontics for dental students, ed. 3, London, 1976, The Macmillan Press. 2. Edwards, J. G.: The prevention of relapse in extraction cases, AM. J. ORTHOD. 60: 128-141, 1971. 3. Parker, G. R.: Transseptal fibers and relapse following bodily retraction of teeth: A histologic study, AM. J. ORTHOD. 61: 331-334, 1972.
4. Thompson, H. E.: Speculations on the potentialities of connective ti~ur fibers. &\I .I ORIHOD 41: 778-789, 1955. 5. Reitan, K.: Tissue rearrangement during retention of orthodonticall) rotated teeth. Angle Orthod. 29: 105-113, 1959. 6. Crum, R. E., and Andreasen, G. F.: The effect of gingival fiber surgery on the retention of rotaled teeth. AM. J. ORTHOD. 65: 626-631, 1974. 7. Thompson, H. E.: Orthodontic relapses analyzed in a study of connective tissue fibers, AM. J. ORTHOD. 45: 93-109, 1959. 8. Reitan. K.: Clinical and histologic observations on tooth movement during and after orthodontic treatment. AM. J. ORTHOD. 53: 121.745, 1967. 9. Reitan, K.: Principles of retention and avoidance of posttreatment relapse. AM. J. ORTHOD. 55: 776-790. 1969. 10. Edwards, J. G.: A study of the periodontium during orthodontic rotation of teeth, Aw. J. ORTHOD. 54: 441-461, 1968. 11. Edwards, J. G.: A surgical procedure to eliminate rotational relapse, AM. J. ORTHOD. 57: 35-46, 1970. 12. Brain, W. E.: The effect of surgical transsection of free gingival fibers on the regression of orthodontically rotated teeth in the dog, AM. J. ORTHOD. 55: 50-70, 1969. 13. Boese, L. R.: Increased stability of orthodontically rotated teeth following gingivectomy in Mucuca rimestrina, AM. J. ORTHOD. 56: 273-290, 1969. 14. Goldman, H. M.: Topography and role of the gingival fibers, J. Dent. Res. 30: 331-336, 1951. 15. Smukler, H., and Dreyer, C. J.: Principal fibers of the periodontium. J. Perio. Res. 4: 19-25, 1969. 16. Black, G. V.: Special dental pathology, ed. 3, Chicago, 1924, Medico-Dental Publishing Company, pp. 28-29. 17. Amim, S. S., and Hagerman, D. A.: The connective tissue fibers of the marginal gingivae, J. Am. Dent. Assoc. 47: 271-281, 1953. 18. Gianelly, A. A., and Goldman, H. M.: Biologic basis of orthodontics, Philadelphia, 1971, Lea & Febiger. 19. Fullmer, H. M., and Lillie, R. D.: The oxytalan fiber: A previously undescribed connective tissue fiber, J. Histop. Cytochem. 6: 425-430, 1958. 20. Fullmer, H. M., Sheetz, J. H., and Narkater, A. J.: Oxytalan connective fibers: A review. J. Oral Pathol. 3: 291-316, 1974. 21. Erikson, B. E., Kaplan, H., and Aisenberg, M. S.: Orthodontics and transseptal fibers. AM, J. ORTHOD. ORAL SURG. 31: l-20, 1945. 22. Thompson, H. E., Meyers, H. J., Waterman, J. M., and Flanagan V. G.: Preliminary macroscopic observations concerning the potentiality of supra-alveolar collagenous fibers in orthodontics, AM. J. ORO~ THOD. 44: 485-497, 1958. 23. Wiser, G. M.: Resection of the supra-alveolar fibers and the retention of orthodontically rotated teeth, (Abstr.), AM. J. ORTHOD. 52: 855-856, 1966. 24. Atherton, J. D., and Kerr, N. W.: Effects of orthodontic tooth movement upon the gingivae, Br. Dent. J. 124: 555-560, 1968. 25. Atherton, J. D.: The gingival response to orthodontic tooth movement, AM. J. ORTHOD. 58: 179-186, 1970. 26. Burket, L. W.: The effects of orthodontic treatment on the soft periodontal tissues, AM. J. ORTHOD. 4% 660-671, 1963. 27. Huettner, R. J.: Experimental histologic study of the effects of orthodontic movement on the gingiva and periodontal membrane in the Macucu rhesus monkey (Abstr.), AM. J. ORTHOD. 46: 929, 1960.
Republic of South Africu
Extraction spaces closed during the course of orthodontic therapy tend to rr-open. ” ‘. ‘I whereas orthodontically rotated teeth ure prone to relapse. ‘H One of the mujor 1~uust3 (?/ spaces opening between teeth is the supru-alveolar soft tissues which do not ctlways udupt to the new tooth positions. 3, 3, i, 9. lo, 12.‘RSeven patients requiring extra&on of upper.first premolar teeth as part of their orthodontic, treatment were selected for thi,c .studv. Tattoo murks were placed in the uttached gingirwe close to the upper canine teeth. The c~trnine.~ were then retracted orthodontically across the extraction spaces. The left sidll WI.S designated the control side and the right side the experimentul side. Immedintel~ ujier completion of retraction, the attached gingiva was surgically detached from the canine teeth on the experimental sides. The canines on both sides were retuined in their new positions for 8 weeks following spuce closure. The amount of relapse or recoil of the gingivae was measured. In this study the gross gingival changes were similar to those described by Atherton and Kerr,” Atherton, 25Edwards.’ The tuttoo marks moved distullj with the retructed canines. The umount of gingival movement MUS similar on both experimental und control sides and ranged between 49.4 percent and 82.4 percent of the retraction distance. Very little recoil or relapse of the gingivae nccurretl,fi,llowing surgicul detuchment from the canines. The results of this study indicate thut the gingi\‘ae appear to udapt to the new tooth position und that relapse qf cunines retructed across extraction sites in the maxilla is not necessarily caused by the supra-czhleolur soft ti.ssues. Key words:
Canines, retraction,
periodontal
surgery, relapse
T
he extraction of teeth may be required in orthodontic treatment to satisfy the demands made by function, esthetics, and stability.’ Notwithstanding attention to detail during treatment, certain undesirable changes are seen during and after retention. Spaces may open between teeth approximated at extraction sites, 2* 3 while derotated teeth tend to return to their original positions. 4-6 The elasticity of the supra-alveolar soft tissue is cited by Thompson,4, 7 Reitan,5, 8, s Edwards,2* lo* ‘I and otherG 12, l3 as a major cause of this type of relapse. Connective tissue fibers of the supra-alveolar system join the attached gingivae to the alveolar bone and cementum of the teeth. The dentogingival or A, B, and C groups of fibers14, I5 attach the marginal and attached gingivae to the teeth (Fig. 1, a), while the transseptal fibers originate in the cementum of adjacent teeth in the dental arch and traverse the interdental septa16 (Fig. 1, b). Included in this system are the circular fiberI (Fig. 1, c) and the vertical and horizontal fiber groups” (Fig. 1, d). Fullmer and Lilliels reported oxytalan fibers which have “elastic-like” properties in the connective tissues of human gingivae. EdwardslO noted that in orthodontically rotated 610
0002.9416/80/120610+13$01.30/0
0
1980 The C. V. Mosby CO.
Volume 78 Number 6
Muxilltrry
Fig
Fig
la
DENTOGINGIVAL
Fig
lc
CIRCULAR
lb
TRANSEPTAL
retraction
611
FIBRES
FIBRES
Fig
FIBRES
Id
HORIZONTAL
VERTICAL
Fig.
canine
1. The
supra-alveolar
fiber
and
FIBRES
network.
teeth these fibers were more numerous and more clearly defined than in nonrotated teeth. Parker,3 in a study on ikfacaca rhesus monkeys, found that the oxytalan fibers are associated and intermingled with collagen fibers, particularly those collagen fibers under stress. They were seen to arise from “connective tissue strands” and none were seen to attach to bone, findings which Fullmer and colleagueszO confirm. EdwardslO postulated that a possible function of oxytalan fibers is to prevent overstretching of tissues in stressed areas. Erikson and associateszl concluded that the transseptal fibers have the capacity to separate approximated teeth at extraction sites. Reitan *, s demonstrated graphically that a large proportion of orthodontic relapse may occur within the first 2 hours after removal of an appliance. Since the work of Thompson and co-workers,22 many research workers have also advocated various forms of surgery to relieve the tension in the supra-alveolar fibers following orthodontic movement. 2, 3, 6, 11-13In these studies the authors are concerned with relapse of orthodontically moved teeth following surgery and compare this movement to that of control teeth. Atherton and Kerrz4 and Athertonz5 described the superficial gingival changes that take place during orthodontic retraction of maxillary canine teeth. They placed a small tattoo mark on the buccal aspect of the mesial interdental papilla of the canine being retracted. As the teeth were moved distally, the tattoo mark appeared to be “left behind. ” The gingivae on the distal aspect accumulated until the papillae appeared enlarged with folds or creases extending vertically from them. Edward? associated the presence of these gingival clefts with orthodontic relapse.
Fig.
2. Tattoo
marks
in the attached
gingivae
The purpose of the present study is to describe the gross changes that take place in the gingivae during upper canine retraction across an extraction site, to measure the amount of movement of the gingivae relative to retracted canine teeth, and to determine whether the gingivae adjacent to the orthodontically moved teeth adapt to the new tooth positions or whether they behave in an elastic fashion. Materials and methods Seven patients with Angle Class II, Division 1 malocclusions constituted the sample in the study. They all required the extraction of upper first premolar teeth as part of their orthodontic treatment. Their ages ranged from 12 years to 18 years, and they included three girls and four boys. The patients ’ upper canines, second premolars, and molars were banded and leveled, following which the upper canines were retracted individually. Subsequent to banding, three tattoo spots were placed in the buccal attached gingivae opposite the distal quarter of the canine teeth. They were arranged in a vertical direction 1 to 2 mm. apart (Fig. 2). These tattoo marks were made by introducing sterile India ink into the lamina propria. Retraction of the upper canines was accomplished by using 0.021 by 0.021 inch looped sectional arches which were reduced posteriorly to facilitate activation. Rampton headgear were worn between 8 and 10 hours a day to preserve anchorage of the upper posterior buccal segments. Comparison of the pre- and posttreatment study models in Figs. 3 and 4 shows that the molar relationships were maintained. On completion of canine retraction, the teeth were retained for a period of 8 weeks by means of straight 0.021 by 0.021 inch sectional arches while headgear wear was continued. Lateral cephalometric radiographs were taken of each patient prior to and at the completion of upper canine retraction. These radiographs were traced by independent orthodontists and the tracings were compared. In each instance the pre- and postretraction cephalometric tracings were superimposed on the palatal planes at ANS. The distances from the pterygoid vertical (PTV) to the distal aspect of the upper first molars were also measured and compared (Fig. 7). In all cases, on the basis of cephalometric evidence, it
Volume 78 Number 6
A4axillaiy
canine
retraction
613
Fig. 3. Study models-left side. I, Before canine retraction. II, On completion of canine retraction showing preservation of posterior anchorage.
Fig. 4. Study models-right side. I, Before canine retraction. II, On completion showing preservation of posterior anchorage.
of canine retraction
appears that there was less than 1 mm. of mesial movement of the upper first molars during canine retraction. The gross gingival changes were recorded before, during, and after retraction of the canines, while photographs and study models were taken prior to and after distal retraction of the canine teeth. To study the amount of gingival movement relative to tooth movement, the following measurements were made: 1. “The canine retraction distance” from the distal contact point of the canine to the mesial contact point of the second premolar (Fig. 5, A and Table I, column A). 2. The distance between the most occlusal tattoo mark and the contact point of the upper second premolar, referred to as the “tattoo retraction distance” (Fig. 5, B and Table I, column B). 3. At the end of canine retraction the distance between the most occlusal tattoo mark and the contact point between the upper second premolar and canine teeth was again measured (Fig. 6, C and Table I, column C).
614
MrColltrtn
Table
rvtd
I. Gingival
Presron
movement
relative
to linear
tooth
movement
Pafient
Side
A (mtn.)
B (mm.)
C (mm.)
I) (mm .)
I
Left Right Left Right Left Right Left Right Left Right Left Right Left Right
7.5 8.4 9.1 9.3 1.2 1.5 1.5 1.4 1.4 7.5 7.1 7.4 5.4 5.7
10.9 I I.0 12.0 12.4 6.5 1.5 7.1 1.5 1.4 1.5 8.8 9.0 6.1 6.4
5.3 4.9 6.9 7.2 2.5 3.0 3.7 3.8 3.7 3.X 3.0 2.8 2.4 2.5
5.6 6. I 5.1 5.2 4.0 4.5 4.0 3.7 3.7 3.7 5.8 6.2 3.7 3.9
2 3 4 5 6 7
E (percenr) 74.74 12.6% 56.1% 55.97<> 55.5% 60.0% 53.3% SO.OW 50.0% 49.4% 80.3% 82.48 68.5% 68.7%
F (mtn.) 1.9 2.3 4.0 4.1 3.2 3.0 3.5 3.7 3.7 3.x 1.3 I.2 I .7 I.8
The left side is the control side. The right side is the surgical side. Column A shows the distance from the distal surface of the canine to the mesial surface of the second premolar tooth (the distance over which the canine is retracted). Column B shows the distance between the most occlusal tattoo mark and the mesial aspect of the second premolar tooth prior to canine retraction. Column C shows the distance between the most occlusal tattoo mark and the second premolar after retraction of the canine tooth. Column D shows the total gingival movement, which is Column B minus Column C. Column E shows the percentage of gingival movement relative to the canine, which is Column D -X 7 = Percentage Column A Column F shows which is Column
the gingival “stretch or lag,” A minus Column D.
which
is total tooth
movement
minus
total gingival
movement,
It was possible to calculate gingival movement which resulted from the canine retraction by comparing the positions of tattoo marks prior to and on completion of tooth movement (Table I, column D). It was also possible to express the gingival movement as a percentage of the distance through which the canines were moved (Table I, column E). Gingival Canine
movement
retraction
distance
x loo =
the percentage of gingival movement relative to tooth movement.
All measurements were recorded with the aid of fine-point dividers and a Vernier scale which was graduated in tenths of a millimeter. Five independent measurements were recorded, and the mean of these was calculated and used as the effective value. The next stage of the experiment was designed to examine the stability of the attached gingivae in their new positions. The sample of seven patients was divided into two groups. Group A comprised three patients, and the remaining four patients made up Group B. Both groups were subjected to surgical procedures on their right sides, the left sides remaining for control purposes. Prior to the surgical procedures, retention arches were placed while headgear wear was continued. Group A. The surgical procedure is illustrated in Fig. 8. The surgery followed admin-
Volume 78 Number 6
Maxillury
Fig. 5. Landmarks retraction distance.
measured prior to orthodontic retraction B is the tattoo-retraction distance.
Fig. 6. Landmarks
Table
II. Postsurgical Patient
recoil
measured
on completion
of the
cunine
canine
of canine
teeth.
retraction
A is the
615
canine-
retraction.
or relapse A (mm.)
Side
Left Right Left Right Left Right Group Left Right Left Right Left Right Left Right
Group 5.3 4.9 6.9 1.2 2.5 3.0 B (includes 3.1 3.8 3.1 3.8 3.0 2.8 2.4 2.5
B (mm.)
C (mm.)
5.3 5.3 6.9 1.2 2.5 3.7
0 0.4 0 0 0 0.1
3.1 3.9 3.1 4.0 3.0 3.4 2.4 2.8
0 0.1 0 0.2 0 0.6 0 0.3
A
papillectomy)
The left side is the control side. The right side is the surgical side. Column A shows the distance between the most occlusal tattoo mark and the second premolar after retraction of the canine tooth. Column B shows the distance between the most occlusal tatoo mark and the second premolar after the fiber cuts. Retention appliances were in place to maintain the tooth positions as far as possible. Column C reflects the recoil of the gingivae, which is Column B minus Column A. No measurable recoil was found on the left (experimental) side.
PATIENT
PA",
BEFORE
-
AFTER
--~--
A
Fig. 7. Before- and after-treatment lateral cephalometric ANS.
tracings superimposed
on the palatal plane at
&ration of a local anesthetic and was aimed at detaching the gingivae from the teeth. This surgical procedure is referred to as the circumdental fiber cut. The gingival cleft which resulted from the folding of the gingival tissues during tooth retraction was incised as follows: On the distal side of the canines in the line of the gingival cleft, a vertical incision was made on both the buccal and palatal sides. These were extended to meet in the co1 area of accumulated tissue and approximately in the region of the tooth contact point (Figs. 8 and 9). The vertical incisions on the buccal side extended 2 to 3 mm. into the buccal mucosa. Both the palatal and buccal incisions penetrated through to the periosteum and bone. These vertical incisions were aimed at releasing residual tension or pressure which may have built up in the region of the cleft. Group B. In Group B the same circumdental and vertical incisions were made. In addition, a papillectomy of the accumulated tissue on the distal side of the retracted canines was performed (Fig. 9). Fig. 10 shows the extent of the papillectomy in the vertical plane. The purpose of the procedure was to remove this cuff of tissue which possibly could have prevented the buccal and palatal attached gingivae from relapsing or recoiling. Forty-eight hours after the surgical procedure the relapse or recoil of the gingivae was measured in both Groups A and B. This was done by measuring the distance between the most occlusal tattoo marks and the contact point of canine and second premolar (Fig. 6 and Table II, column B).
l’olumr 78 Number 6
Fig.
Maxillury
8. 7, Circumdental
Fig. 9. 7, Circumdental Papillectomy
incision.
incision. of the accumulated
2, Vertical
incision
2, Vertical incision gingival tissue.
along
along
canine retraction
67 7
the line of the gingival
cleft
or groove.
the
cleft
or groove.
line of the vertical
3,
Findings
Between 4 and 5 months were required to retract the canines. On the experimental as well as the control sides there was a heaping-up of the gingivae on the distal aspect of the teeth being retracted. At maximum canine retraction, when the contact point with the second maxillary premolar was re-established, the accumulated gingivae were seen as grossly enlarged buccal and palatal interdental papillae (Fig. 11). These findings were previously reported by Atherton and Kerr,24 Atherton,25 and Edwards.* The enlarged papillae in both groups appeared to be twice the size of normal papillae. The height of the enlarged papillae was measured to be an average of 4 mm. as against the
Fig.
Fig. 11. An example the retracted canine
10. 7 shows
of the slit or groove tooth.
the vertical
extending
extent
from
of the papillectomy.
the “heaped-up”
tissue
on the distal
aspect
of
preretraction average height of 2 mm. The vertical height was measured between the most apical portion of the gingival margin around the premolar teeth and the apices of the papillae. Extending vertically from the enlarged papillae to the junction of the alveolar mucosa and the attached gingivae, a groove or a slit appeared (Fig. 11). The slit was seen on the buccal and palatal sides and appeared to enter the papillae; however, no tunnel was formed in the buccal and palatal aspects. During distal movement of the retracted canines the “red patch” described by Atherton and Kerr*-’ became evident on the mesial side of the upper canine teeth (Fig. 12). of the This “patch” was triangular in shape, with its base against the mesial surfaces upper canines. The red area was depressed below the level of the surrounding gingivae. The deeper red color of the triangle could be attributed to the thin nature of the epithelium which appeared to be unkeratinized in this sample. After the retention period of 2 months which followed the surgical release of the supra-alveolar fibers, the red patch disappeared on both surgical and control sides. This area, however, still appeared flattened or slightly depressed below the surrounding gingivae. At the onset of canine retraction the adjacent
Volume 78 Number 6
Fig. 12. An example tooth.
hfuxillary canine retraction
of the triangular
depressed
red patch
on the mesial
aspect
of the retracted
619
canine
incisors tended to follow the retracted canines in their distal movements. This resulted in a loss of the previously tight contact points between these teeth (Figs. 10 and 11). The vertical tattoo marks appeared to slope in the direction of canine movement to only a small degree. Gingivul movement. The gingivae marked with the tattoo dots moved distally with the fourteen retracted canines but not in a 1: 1 ratio with these teeth. (Compare A and B in Fig. 13.) The gingival movement is recorded in Table I, column D, and ranged between 3.7 and 6.2 mm. This movement is expressed as a percentage of the canine retraction distance, which ranged between 49.4 and 82.4 percent. The amount of “stretch or lag” relative to the retracted canine teeth is recorded in Table I, column F, and ranged between 1.2 and 4.1 mm. Gingival adaptation. Forty-eight hours after the periodontal surgery in Groups A and B the distance between the second premolar and the most occlusal tattoo mark was recorded (Table II, column B). This distance was compared with the distance between the tattoo mark and the second premolar prior to the surgery (Table II, column A, and Table I, column C). The difference between the two readings (Table II, column C) represents the amount of recoil or relapse of the gingivae that occurred 48 hours after surgery. The recoil ranged between 0 and 0.7 mm. in Group A and 0 and 0.6 mm. in Group B. (Compare Fig. 13, C with Fig. 13, B on the surgical side.) No recoil movement of the gingivae on the control side occurred. Group B had a surgical papillectomy in addition to the periodontal surgery. There was little postsurgical difference in the amount of recoil or relapse between these two groups during the first 48 hours. Following the surgery, the retracted canines became markedly mobile and were rated as being Grade II mobile (according to the rating used by the Department of Periodontics of the University of the Witwatersrand). It appeared that the mobility of the canines was slightly greater, but still Grade II mobile, in Group B where the papillectomy was performed. No pain or discomfort was reported by these patients. The depth of the gingival crevice was measured prior to and after surgery and was not significantly altered by the
Fig. 13. Right side. A, Position of upper canine and tattoo marks prior to distal retraction af these teeth. B, Position of upper canine and tattoo marks on completion of canine retraction. C. Position of tattoo marks 48 hours after periodontal surgery.
Fig. 14. Left side. Position of upper marks
48 hours
A, Position of upper canine and tattoo after
periodontal
canine marks
and tattoo marks prior to distal retraction of these on completion of canine retraction C, Position
teeth. B, of tattoo
surgery.
surgical procedures. At the end of the retention period, during which time the retraction space was maintained, the periodontal situation was again assessed. There was no measurable change in the depths of the gingival crevices during the retention phase. At the same examination no further recoil of the gingivae was demonstrated on either the experimental or the control sides. Discussion The gross changes seen in the gingivae during retraction of the upper canines are similar to those described by Atherton and Kerr,*” Atherton,‘j and Edwards.? By measuring the changes that took place in the position of the gingival tattoos, it was possible to show that the soft tissue of this area moves between 49.4 and 82.4 percent of the tooth movement. EdwardslO found that when teeth were orthodontically rotated the gingivae followed the rotated teeth through the same degree of movement. EdwardslO found this gingival movement to be consistent throughout his studies on rotated teeth. In our study the discrepancy in movement that was noted between the soft tissue and tooth movement could possibly be attributed to one or a combination of factors: (1) the supra-alveolar fibers and gingivae are “elastic” and are “stretched” as the tooth is retracted distally, (2) the supra-alveolar tissues actively adjust themselves to the new tooth positions (which has been refuted by Erikson and associates*’ and Burket*‘j), (3) pathologic tearing of the fibers as suggested by Heuttner.2’ A number of authors have investigated the potential effects of the supra-alveolar fibers
Volume 78 Number 6
Maxillary
canine
retraction
621
in causing relapse of orthodontically moved teeth. In their studies, surgery was performed on the gingivae either before, during, or after a retention period and the teeth were subsequently allowed to relapse. The amount of relapse was measured and compared with relapse seen in control teeth. In the present study a different procedure was used. Immediately on completion of distal retraction of the upper canine teeth, periodontal surgery was performed in order to release the gingivae from these teeth. The canines were held in retention immediately following retraction, and subsequent to the surgical procedure the gingivae were allowed to recoil or relapse on their own. The changes in gingival position were recorded. Our procedure was based on the work performed by Edwards,‘O, l1 who worked on orthodontically derotated teeth. His results appear to indicate that the gingivae do not adapt to new tooth positions but behave in an “elastic-like” manner. In the present study it was shown that the gingivae close to the teeth being moved followed the tooth movement by between 49.4 and 82.4 percent of the retraction distance. In the main, it was thought that the surgical cutting of all the supra-alveolar fibers would release the gingivae from the teeth and would establish whether or not the gingivae adapt to the tooth movement or react in an elastic-like fashion, as suggested by the work of Edwards.‘O, l1 The results of this study indicate that, after surgery, very little recoil of the gingivae occurs. The papillectomy in Group B did not cause the adjacent gingivae to recoil or relapse more than those in Group A. For this reason, we believe that there must be some adaptation of the gingival soft tissue to new tooth positions. This adaptation would reduce, to some extent, the role which the gingival tissues are said to play in orthodontic relapse. This is particularly so when teeth have been approximated at an extraction site. Conclusions 1. The gross gingival changes that take place during distal retraction of upper canine teeth are characterized by an accumulation of gingival tissue on the distal aspects of these teeth. Slits or clefts extend vertically from this accumulated tissue on the palatal and buccal sides, while on the mesial aspects depressed triangular red patches appear. 2. The attached and marginal gingivae adjacent to the upper canine teeth move distally with the retracted canine, but not in a 1: 1 ratio. The gingival soft tissues move distally between 49.4 and 82.4 percent of the canine-retraction distance. In determining these percentages, we have not taken into account anchorage loss. In all of our patients studied the anchorage loss appears to be minimal and to be less than 1 mm. as measured on the cephalometric radiographs. 3. After periodontal surgery which detached the gingivae from the retracted teeth, negligible if any relapse or recoil of the gingivae was seen to occur with our method of measurement.
REFERENCES 1. White, T. C., Gardiner, J. H., and Leighton, B. C.: Orthodontics for dental students, ed. 3, London, 1976, The Macmillan Press. 2. Edwards, J. G.: The prevention of relapse in extraction cases, AM. J. ORTHOD. 60: 128-141, 1971. 3. Parker, G. R.: Transseptal fibers and relapse following bodily retraction of teeth: A histologic study, AM. J. ORTHOD. 61: 331-334, 1972.
4. Thompson, H. E.: Speculations on the potentialities of connective ti~ur fibers. &\I .I ORIHOD 41: 778-789, 1955. 5. Reitan, K.: Tissue rearrangement during retention of orthodonticall) rotated teeth. Angle Orthod. 29: 105-113, 1959. 6. Crum, R. E., and Andreasen, G. F.: The effect of gingival fiber surgery on the retention of rotaled teeth. AM. J. ORTHOD. 65: 626-631, 1974. 7. Thompson, H. E.: Orthodontic relapses analyzed in a study of connective tissue fibers, AM. J. ORTHOD. 45: 93-109, 1959. 8. Reitan. K.: Clinical and histologic observations on tooth movement during and after orthodontic treatment. AM. J. ORTHOD. 53: 121.745, 1967. 9. Reitan, K.: Principles of retention and avoidance of posttreatment relapse. AM. J. ORTHOD. 55: 776-790. 1969. 10. Edwards, J. G.: A study of the periodontium during orthodontic rotation of teeth, Aw. J. ORTHOD. 54: 441-461, 1968. 11. Edwards, J. G.: A surgical procedure to eliminate rotational relapse, AM. J. ORTHOD. 57: 35-46, 1970. 12. Brain, W. E.: The effect of surgical transsection of free gingival fibers on the regression of orthodontically rotated teeth in the dog, AM. J. ORTHOD. 55: 50-70, 1969. 13. Boese, L. R.: Increased stability of orthodontically rotated teeth following gingivectomy in Mucuca rimestrina, AM. J. ORTHOD. 56: 273-290, 1969. 14. Goldman, H. M.: Topography and role of the gingival fibers, J. Dent. Res. 30: 331-336, 1951. 15. Smukler, H., and Dreyer, C. J.: Principal fibers of the periodontium. J. Perio. Res. 4: 19-25, 1969. 16. Black, G. V.: Special dental pathology, ed. 3, Chicago, 1924, Medico-Dental Publishing Company, pp. 28-29. 17. Amim, S. S., and Hagerman, D. A.: The connective tissue fibers of the marginal gingivae, J. Am. Dent. Assoc. 47: 271-281, 1953. 18. Gianelly, A. A., and Goldman, H. M.: Biologic basis of orthodontics, Philadelphia, 1971, Lea & Febiger. 19. Fullmer, H. M., and Lillie, R. D.: The oxytalan fiber: A previously undescribed connective tissue fiber, J. Histop. Cytochem. 6: 425-430, 1958. 20. Fullmer, H. M., Sheetz, J. H., and Narkater, A. J.: Oxytalan connective fibers: A review. J. Oral Pathol. 3: 291-316, 1974. 21. Erikson, B. E., Kaplan, H., and Aisenberg, M. S.: Orthodontics and transseptal fibers. AM, J. ORTHOD. ORAL SURG. 31: l-20, 1945. 22. Thompson, H. E., Meyers, H. J., Waterman, J. M., and Flanagan V. G.: Preliminary macroscopic observations concerning the potentiality of supra-alveolar collagenous fibers in orthodontics, AM. J. ORO~ THOD. 44: 485-497, 1958. 23. Wiser, G. M.: Resection of the supra-alveolar fibers and the retention of orthodontically rotated teeth, (Abstr.), AM. J. ORTHOD. 52: 855-856, 1966. 24. Atherton, J. D., and Kerr, N. W.: Effects of orthodontic tooth movement upon the gingivae, Br. Dent. J. 124: 555-560, 1968. 25. Atherton, J. D.: The gingival response to orthodontic tooth movement, AM. J. ORTHOD. 58: 179-186, 1970. 26. Burket, L. W.: The effects of orthodontic treatment on the soft periodontal tissues, AM. J. ORTHOD. 4% 660-671, 1963. 27. Huettner, R. J.: Experimental histologic study of the effects of orthodontic movement on the gingiva and periodontal membrane in the Macucu rhesus monkey (Abstr.), AM. J. ORTHOD. 46: 929, 1960.