Edwards 1977 Diastema and Frenum

American Journal of ORTHODONTICS Volume 71, Number 5, May, 1977

ORIGINAL ARTICLES

The diastema, the frenum, the frenectomy: A clinical study

John G. Edwards, D.D.S., M.S. Charlotte, N. G.

M axillary midline diastemas are relatively simple to close rapidly with modern orthodontic mechanics, but the frequent instability of the approximated incisors can be bothersome to the patient and disconcerting to the orthodontist who is attempting to achieve cosmetic perfection in the anterior portion of the mouth. Many factors can contribute to the reopening of maxillary anterior diastemas : (1) improper axial inclination of the roots of the central incisors ; (2) tooth size discrepancies (narrow maxillary lateral incisors) ; (3) pernicious habits (thumb- or finger-sucking, lip-biting, tongue-thrusting, etc.) ; (4) delete- rious ocelusal patterns which would tend to place lateral forces on the central incisors in shifts from centric relation to centric occlusion or during any of the other excursions of the mandible ; (5) the actual anatomy of the teeth (central incisors with larger mesiodistal dimensions at the cervical portions of the teeth than at the incisal edges) ; and (6) possibly even muscular imbalances in the oral region. But perhaps the most frequently alleged etiologic agent in relapse of approximated teeth in a previous area of diastema is the superior (maxillary) labial frenum and/or its associated interdental soft tissues.

The present investigation has attempted to study the maxillary anterior frenum as it relates to the relapse (“physiologic recovery”l’) phenomenon observed after the orthodontic closure of diastemas and to develop an efficacious method of eliminating the possible contributing influences of this frenal tissue on relapse of the approximated maxillary central incisors.

Review of the problem

The maxillary labial frenum is a fold of tissue, usually triangular in shape, extending from the maxillary midline area of the gingiva into the vestibule and

489

490 Edwards Am J. Orthod. Ma!/ 1977

midportion of th0 upper lip. The mucogingival junction and alveolar mucosil involved in the frenum are supposedly no different structurally than in an>- Other area. Of the mouth, except for the matter Of (‘ollfiguratioll.” Thtx masillaryi labial frenum originates as a postcruptirc remnant of the tectolabial bands, which are embryonic structures appearin g at a~)l)l~o?tirriatel~ 3 months in utero and connecting the tubcrclc Of the upper lip to the palatine papilla.‘”

The relocaticm Of the attachment in an apical direction is usually aceomplishetl by the normal \-ertical growth Of the alveolar prOccss, The failure of the attached frenal fibers to migrate apically results in a residual hand Of tissue between the nmsillary central incisors, which has been implicatccl as an important causative factor in persistent midinc tliastemas. The residual frenal fibers which persist between the maxillary ecntral incisors may also attach to the pcriosteum and iii- ternal connective tissue Of the V-shaped intermaxillary suture. Bray” has found a high correlation bctw-cen thcl pretreatment existence of this “nOtching” of t,he interseptal alveolar crest ;ultl the relapse of’ ortliotlonticall!:~all~ treated masillar? midline diastemas. In addition to prevcnt,ing the c*IOsurc Of space between the maxillary central incisors, and thus creating an arca for food impaction, the frcnal tissues havcr been implic~atctl with poor oral hygiene, due to difficultp in toothbrush&, ant1 the resultant inflammatory pcriotlontal destruction.”

Although most tests state that an abnormallyv large ant1 marginally positioned labial frcnum may result in ii persistent masillay mitllinc tliastcma, there is also apparent agreement in both the orthotlontic and pedodont,ic literature that rarely should any portion OF even an “abn0rma.l” labial frenum be removed prior to eruption of the maxillary lateral in&n3 ancl caanincs, sinec> it has bcc~ii observctl that most tliastemas close autonomously with the final csruption o-f the remaining anterior teeth.7. I1 TavlOF’ describes the kstencc Of a maxillary midline diastema as normal in 98 per cent of 6- to 7-year-old children, whereas only 7 per cent of a 12. to 1%year-old population sample retain thcsr tliastemas. Norcover. Dewcl’ has stated that early (“prevcnti+‘) frcnectomies without prior orthodontic closure in diastcma situations may result in scar formation, which itself might tend to prevent normal mcxial movemc~nt Of the incisOrs.2”

Gibbs14 found ~III intermingling of the frcnal tissue with the transscptal fibers and, therefore, (lit1 not advocate car1.v frcndomy f’or fear that the cs- cision Of the frenum n-ould also sever the transscptal fibers and reduce the nat- ural forces acting to bring the central in(*isors togcthct.. Most Oral anatomists, howcrer, woultl have dificulty agreein g with suc~h an argument, since the fibers Of the transseptal group have never bern shown to possess elastic properties. Baum,” in addition, indicated that the transseptal fibers tlitl not even span the distance across a midline tliastcma but inac~rtctl into a raphc overlying the midline suture of the maxilla.

111 any case, the current CY~SCJ~~U~ among clinicians apllcars to be that frencc- tomies have clinical validity onl)- after the eruption Of all six pcrmancnt anterior teeth has failed to close the diastema, ant1 then only in c,onjunction with orthodontic treatment.‘, ‘I Thcrc is also grncral agreement, among practitioners that orthodontic calosurc Of tliastcmas, which were presumably eausctl IQ- :~bnOrm:Il frenal tissues, without the suhs;cquent surgical escisifm Of the frenums very Often

Volume 71 Number 5 Dinstemn, frewum, fretlectomy 491

results in a relapse separation of the teeth after removal of the orthodontic retaining appliances.‘> 2l l1 But, interestingly, there is a definite paucity of detailed clinical evidence directly correlating the existence of “abnormal” frenums (frenums which appear inordinately large and/or attached especially close to the gingival margin) and maxillary midline diastcmas which persist after the eruption of the six permanent maxillary anterior teeth or indicating that such frenal tissue does, indeed, consistently cause relapse movement of orthodontically approximated incisors in a midline diastema situation.

Disagreement also exists concerning the histologic morphology of the frenum, particularly relating to the presence or absence of muscle tissue. Knox and Young’* have stated that the frenum originates in the orbicularis oris and re- ported that their histologic sections contained collagen as well as elastic and muscle fibers. Archer? indicated that the depressor septi muscle originates by fusion with the dense connective tissue between the central incisors and that its fibers diverge to interweave with the orbicularis oris. He has even described a surgical technique for apical repositioning of this muscle band without complete dissection. In contradiction, several other researchers concluded that no muscle is present in the maxillary labial frenum.?, ~3 24

Possibly the most thorough work in this area was published by Henry, Levin, and Tsaknis,16 who concluded quite definitely that of the four basic types of tissue within the human body (epithelium, connective tissue, nerve, and muscle) only the muscle tissue was notably absent as an integral component of the maxillary frenum. They also noted that there existed no microscopic differences between an abnormal or aberrant superior labial frenum and a frenum of more normal configurat,ion and position. Irnerestingly, their research demonstrated the prcs- ence of a significant amount of elastic fibers occasionally traversing the entire length of the frenum. Elastic fibers also appeared to originate in the periosteum covering the anterior maxillary alveolus and then to permeate the connective tissue of the overlying frenum. In conclusion, these authors believe that the detri- mental capacities of the maxillary midline frenum are entirely due to its elastic and collagenous components and not a result of direct muscle tension.lG

Campbell, Moore, and Matthews5 microscopically examined the frenal and interdental soft tissues in areas where maxillary midline diastemas had been previously closed by orthodontic therapy. Their histologic observations of the tissue sections of the transseptal region and especially of the interdental papilla resemble very closely Edwards’ description of the configuration of the excess gingival tissue which accumulates between two approximated teeth in an extraction area.” Campbell and associates also described a marked increase in the amount and definition of oxytalan fibers in the interdental tissues of the orthodontically approximated central incisors (as compared to the control specimens). Interest- ingly, the same phenomenon was earlier illustrated in work by both Parkerzl and Edwa.rdsy on the interdental tissue between two orthodontically approximated teeth in extraction sites.

When the diastemas were closed, the transseptal fibers were seen by Campbell and associates” to be convoluted and compressed in a coiled-up manner, whereas one of the histologic studies on interdental tissue after closure of extraction sites

492 Edwards 4711. J. Orthod. May 1977

noted that the transseptal fibers, especially those fibers closest to the alveolar crest, had apparently reorganized and presented a rather normal configuration after 10 to 14 months of rctcntionS Edwards hypothesized that the heavy orthodontic forces employccl tluring final closure of the ext,raction site and the approximation (paralleling) of t,hc roots deprived the compressed transseptal fibers of a sufi-

cient blood supply ; thus, completely new transseptal fibers formed in place of the old ones which had been destroyed by ischemia.!’ Such a theory would be SUP-

ported by the observations oi’ increased stability in extraction areas where the dental roots (in addition to just the crowns of the teeth) had been approximated.l& 21

The work of Ten Catc and associates’” would lend crctlcnce to Edwards’ findings that there apparently exists a physiologic process which can achieve remodeling of the transseptal liga.mcnt, namely, fibroblastic activity. Their research describes t,hc fibroblast as capable of both synthesizing ant1 &grading collagen simnlta- nrously and, utilizing this ability, 01’ controlling the ortlcrly remodeling of co- lagcn within the periodontal ligament and the decpcr transscptal areas.

Notwithstanding the fact that there exists littlc hut empiric ant1 arbitrar? agreement that the maxillarv frenum plays an important role in causing the reopening of diastemas after orthodontic closure, a number of surgical techniques have been devised to climinatc this untlcsirablc rclapsc pl~c~~onltrno~~. The terms frexectmny alld fr-endonly represent procedures that differ in degree. Frenectomp is the complete removal of the frenum, including its attachment to underlying bone. Frenotomy is the partial removal of the frenum, and is used extensively for periodontal purposes to relocate the frcnal attachment so as to create an increased zone of attached gingiva between the gingival margin and the frenunr.

In his textbook, Archer1 depicts the classic frencctomy technique in which the frenum, interdental tissues, and palatine papilla are completely excised, leaving bone and/or periosteum exposed. In contradiction to many oral surgeons, orthodontists have for ?-cars advocated that the frenectomy procedure be initiated only rafter the diastema has been c10scd,~ since, although there is some evidence that frenectomy prior to orthodontic closure increases thn speed of tooth movement,” the tissue configuration after closure of the diastcma would he less prcdictablc and the speed with which a frenum can 1~ closed is rclativelv rapid, even without early frenectomy.

A number of modifications of the basic frcnectomy operation have bren tlcscribed, including the atlclition of horizontal relaxing incisions at the mucogingival ,juiiction, and the lateral uiitlcrinining of the labial ilttaVh(‘d gingiva ad- .jacent to the excision arca. Clinicians disagree concerning the need -for a dressing over the wound and cvcn concerning the freyucncy and prevention of problems involving hcmatomas in the upper lip following surgical iutcrvention. In addition to t,hc lack of stat,istical studies on the actual need for and/or success of such excision-type frcnectomics, the primary objection to the procednrc is the elimination of the interdental soft tissue (Figs. 1 and 2) and the labial scarring where horizontal rcluxing incisions arc cmployctl.

Bell” has advocated the immediate closure of diastcmas by interdental ant1 subapical ostcotomics. Although 011 c of Bell’s justifications for this surgical al)-

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Volume 71 Number 5 Diastemcc, fremm, frenectonty 493

Figs. 1 and 2. Note the undesirable loss of interdental papilla following classical excision- type frenectomy.5 [From Campbell, P. M., Moore, J. W., and Matthews, J. L.: AM. J. ORTHOD. 67: 139-158, 1975.)

preach is the indisputable unpredictability of retaining closed diastemas, most orthodontists would seriously question his second justification that the con- ventional orthodontic approach to closure of diastcmas is “lengthy and difficult.” In addition, Bell’s conviction that the resistance to active orthodontic movement of teeth and their final stability is the alveolnr holle, and not the gingival and frenal tissues, is in contradiction to recent oral anatomic and physiologic research. If such osteotomies should alleviate relapse in diastema problems, it would more plausibly be due to the surgical interference with the supra-alveolar soft tissues (as in the cases of cortieoectomy’” and septotomy”?) and not the direct manipula- tion of alveolar bone.

Another procedure to eliminate the alleged relapse potential of the maxillary midline frenum is the Z-plasty technique, which does not remove the frenum but is intended to relax the pull of the frenum on the interdental soft tissue.20

Ewen and Pasternakl” were encouraged by the USC of the reverse-bevel (in- verted) gingivectomy procedure on the labial and palatal tissues of all six maxillary anterior teeth. Although their experimental group involved only six patients and the researchers were not primarily interested in relapse caused by midline frenums, their surgical intervention did appear to alleviate the tendency for the diastemas to reopen.

Campbell, Moore, and Matthews” have attempted to increase the stability of orthodontically closed diastcmas by combining the standard excision type of frenectomy and its removal of interincisal soft tissue with either (1) the reverse- bevel gingivectomy labial and palatal to the six anterior teeth or (2) the CSF (circumferential supracrestal fiberotomy) technique developed by Edwards.8 Their preliminary findings favored the combination of frenectomy and CSF procedures.5

Finally, a technique advocated by some periodontists combines a frenotomy with no excision of the marginal papilla and the labial “curtain type” of gingivectomy of the palatal tissue behind the four incisor teeth as described by Frisch, *Tones, and Bhaskar.‘:<

494 Edwards .4m. J. Oythod. May 1977

Statement of the problem

Possibly more than any other etiologic factor, the maxillary labial frenum has been accused of contributing directly and consistently to the reopening of orthodontically closed maxillary diastemas. However, there exists a surprising scarcity of reports directly studying the actual physiologic relationship of the maxillary midline diastema and the maxillary frenum. Nevertheless, various surgical techniques have ~CCH atlvocatcd to eliminate the midline frcnum and its alleged rt- lapse potential.

The purpose of this study is (1) to clinically examine the possible cause-and- effect relationship of frenum t,o diastema, (2) to determine the extent to which an “abnormal” frenum contributes to the relapse phenomenon of orthodontically treated diastemas, and (3) to describe a conservative surgical procedure which will effectively reduce the relapse potential of the frenum in diastema situations.

Methods of investigation

SkIy A. This investigation consisted of three separate studies, The first study sample comprised 308 untreated patients who demonstrated a maxillary midline cliastema antl/‘or il. clinically “abnormal’‘-appearing maxillary frenum. The differentiation between an abnormal and a normal frenum was subjectively detcr- mined by (I) the proximity of the frenal attachment to the interdental gingival margin, (2) the relative width of the frenum at the zone of attachment in the attached gingiva, and (3) the clinical observation of movement and “blanching” of the interdental antl~or palatal tissues as a result of stretching the frenum and upper lip.’ Full eruption of all six maxillary anterior teeth had occurred in the sample groul)s; thus, spontaneous closure of any of the diastemas from subst- quent tooth eruption would not be anticipated.

In all three portions of the investigation the cases which were selected for their demonstration of diastemas did not have anterior teeth congenitally missing, undersized (“peg-shaped”) lateral incisors, or teeth whose incisal edges were not the widest portion of the tooth. Cases with gross discrepancies between the cumulative mesiotlistal width of tooth structure and available alveolar arch length were also not inclutktl in thr study samples. The first group of 308 ~)a- ticnts were obscrvc1c.l antI catcgorizctl as possessing (1) a diastema (2 mm. or Illore, with a mean of 3.X mm.) with a11 “ahnormal”( al~crrant) frcnum, (2) a diastema (2 Inm. or more, with ii mean of 3.0 mm.) with a “normal” (or noncontributory) .frenum, or (3) no diastcma but a11 “abnormal” I’renum.

Study B. The second portion of the investigation consisted of 162 diastema ]MtiPIlts jmcali tliastcma , 3.2 mm) who hatl IWCI~ trcatetl orthodonticall~ arltl whose closed diastcmas had been retained for periods of 16 to 22 months (mean, 19.8 months) before the retaining appliances we&a discoIltinuccl. These patients were examined for relapse (reopening) in the diastema’ areas. Since a correlation of the frenum classification to the reopening of the diastema was the primary focus of this study, a’ pretreatment evaluation (from intraoral photographs) for a, “normal” or “* clbnornrall’ frcnum was recorded for each diastema patient. No surgical intervention in the frcnal or intrrdcntal areas IId l)ccI~ nII(jertakeII in

any of the patients.

Volume 11 Number 5 Diastema, frenum, fresectomy 495

fig. 3. A and 6, Excision of the frenal tissue from the underlying periosteum to a height

approximately 3 mm. into the mucosal tissue. C, Removal of excised frenum from mucosal

tissue. Extensive removal of mucosal tissue is not indicated. D, Denudation of alveolar

bone by sharp excision of periosteum followed by “destruction” of transseptal fibers.

As mentioned above, cases with secondarily associated etiologic factors which could reduce the stability of the orthodontically closed diastemas (for example, missing or misshapen lateral incisors or improperly torqued incisor roots) were not included in the study group. Relapse changes were classified as either (1) negligible, (2) minimal (0.5 to 1.5 mm.), or (3) more than minimal (more than 1.5

496 Edwards Am. J. Orthod. May 1977

Fig. 4. Excess accumulation of gingiva in interproximal area following closure of diastema.

Note “gingival cleft” similar to that found after closure of extraction sites.

mm.). A comparison was also made hetwccn these relapse tendencies and the subjective appearance of the frenal and interdental tissue before active t,hcrapy.

St&y (‘. The final segment of the investigation attempted to evaluate the efficacy of a conservative surgical technique to alleviatrl the possible relapse potential of the soft tissues in the area of a diastcma. Fifty-two patients with maxillary midline diastcmas (mean tliastcma, 3.9 mm.) were included in this study. The configuration and insertion of the labial frenums varied considerably, but the frenums in all cases had been subjectively classified as abnormal or a,bcrrant prior to treatment. A periapical radiograph was taken ot’ each patient to determine the cxistencc of a cleft or “notched” effect in the intcrseptal crest between the central incisors.

After the diastemas had I)cen closetl orthodontically and the root apices of the approximated incisors properly torqucd into a. clivcrging position, the cases wcrc retained in a passive situation with ar~li wires for 8 to 10 months. Following the retention period, the arch wires mere rcmovetl and the patients were observetl for reopening (relapse) of the midline tliastcmas OWI’ a 3-month interval. The cases which did relapse WI’C then re-trcatcll ant1 rctainccl Par 2 additional months before surgical intervention in the frcnal antl interdental soft tissues was initiated.

The basic procedure used in the study is illnstratctl in Fig. 3. A Z&gauge needle was used to infiltrate a small amount of 2 per cent lidocaine (1:50,000) just apical to the marginal gingiva between the central incisors. The needle \vas inserted with an apical angulation until contact was matlc with the periosteum. Commonly, a “ballooning” effect in the more apical and unattached portions of the frenal tissue was observed from injection of even these fen clroys of anesthet-

Volume 71 Nwnber 5

Table I

Lhkste7na-, fremm, fre7hectomy 497

No. of cases Per cent

Diastema with an abnormal frenum Diastema with a normal frenum No diastema but an abnormal frenum

216 70.13 30 9.14 62 20.13

308 100

ic. While the frenum was held taut by stretching the lip outward, a No. 11 Bard Parker blade was used to create a “V”-shaped incision directly adjacent to the lateral borders of the frenum with the apex always apical to the interdental papilla.

These first two incisions were directed medially to meet at the periosteum beneath the frenal mucosa. The frenal tissue which had been separated from the periosteum was then removed from the lip mucosa with surgical scissors. The small amounts of lipid and glandular tissue within the uppermost fringe of the frenum were excised. Next, the transseptal fibers were destroyed by “sawing” and “chopping” movements of the blade in the interdental zone overlying the marginal alveolar crest. If a “cleft” or “notch” in the interseptal bone was discovered by probing during removal of the transseptal fibers, the knife blade was wedged into the suture to dissect the connective tissue in the cleft.

The final step in the procedure consisted of removing the periosteum covering the labial plate of the alveolus which lay directly beneath the excised frenum (an arca of approximately 3 mm. by 5 mm.). The attached gingiva adjacent to the wound was not undermined. No dressings or sutures were employed with this technique. The palatal tissue and the labial interdental papilla were not removed surgically unless there developed an excess or “piled-up” accumulation of gingival tissue (Fig. 4) in these areas as the incisors were approximated. In such situations, a gingivoplasty was performed with curve-bladed scissors; never was the entire palatine papilla or labial interdental papilla excised. The CSF (circumferential supracrestal fiberotomy) procedure was employed only in situations where the incisors had previously been malrotated or where tight interdental contact of all the anterior teeth had not been accomplished, usually as a result of a slight tooth size discrepancy between the maxillary and mandibular incisors.

A periapical radiograph was taken of each patient to compare the postsurgical interseptal bone configuration with the same zone on the pretreatment, radiograph. The healing time and patient discomfort were noted in each case. Four weeks following the surgical intervention, the arch wires were removed and any rclapsc phenomenon was obscrvrd and recortlccl over another 3-month period.

Observations

Study A. The observations concerning the 308 patients who were selected for (lemon&rating a maxillary midline diastema and/or a clinically (‘abnormal” appearing maxillary frenum arc depicted in Table I.

Although more than two-thirds of the patients in this study with diastemas also had aberrant frenal tissue, a one-to-one correlation between “abnormal”

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49% Edwards Am. J. Orthod. May 1977

Fig. 5. A, Extreme diastema associated with “abnormal” frenum. B, “Abnormal” frenum

with no diastema (some overlapping of central incisors). Note that the maxillary canines

and lateral incisors have not even achieved full eruption. C and D, Diastemas apparently

not associated with aberrant frenal tissue.

Table II

Relapses A bnormalfrenum Normal frenum

Negligible 17 (11.4%) 9 (64.2%) Minimal (0.5 mm. to 1.5 mm.) 42 (28.3%) 4 (28.5%) More than minimal 89 (60.0%) 1 ( 7.2%)

(mean 2.7 mm.) (mean 2.4 mm.) 148 14

(9 1.3% of samole) (8.6% of samde)

frenums and maxillary midline diastemas was not observed (Fig. 5)) even in this study group in which the cases mere specifically selected to ?lot demonstrate some of the other suspected etiologic factors of diastemas (missing or narrow lateral incisors, misshapen incisors, pernicious habits, etc.).

Xtzcdy B. The data recorded in this study (Table II) seemed to show clearly a strong, but not absolute, correlation between the existence of a pretreatment clinically determined abnormal frenum and the relapse tendency in a diastema problem.

Two interesting observations from this investigation arc (1) that even in cases where an abnormal frenum appeared to be the sole clinical cause of the

Dinstema, frenum, frenectomy 499

Table Ill

Relapses No. of cases Per cent

Negligible 5 9.6 0.5 to 1.5 mm. 14 26.9 More than 1.5 (mean, 2.8 mm.) 33 63.4

52

Table IV

Relapses No. of cases Per cent

Negligible 36 76.5 I to 1.5mm. 8 17.1 More than 1.5 mm. (mean, 2.6 mm.) 3 6.4

47

diastema., a rather large proportion (39.7 per cent) of the diastemas relapsed 1.5 mm. or less after treatment and (2) that only 64 per cent of the diastema cases with normal frenal tissues show negligible relapse. In addition, although there was decidedly more relapse in cases with abnormal-appearing frenums, significant reopening (35.7 per cent) of the treated diastemas did occur in cases which were classified as having normal frenums prior to treatment. Moreover, there appears to be a negligible quantitative difference between the “abnormal” and “normal” frenum cases which reopened “minimally” after 16 to 22 months (mean, 19.8 months) of retention (28.3 per cent versus 28.5 per cent). In summary, if the cases which relapsed “minimally” are discounted, 84 per cent of the abnormal frenum sample relapsed more than 1.5 mm. (only 10 per cent of the normal frenum sample relapsed more than 1.5 mm.), and only 16 per cent remained stable with negligible reopening (90 per cent of the normal frenum group showed negligible relapse).

Study (I. After the initial orthodontic closure of the fifty-two diastemas and the 8 to 10 months of retention with arch wires, the amount of relapse over the subsequent 3 months was recorded as shown in Table III.

The five patients whose closed diastcmas showed no reversal (relapse) trnd- encies were eliminated from the remainder of the research program, since the primary intent of this portion of the study was to examine the efficacy of a sur- gkal technique in reducing the relapse problem in a diastema situation. Table IV shows the influence which the surgical intervention had on the relapse tendencies in the remaining forty-seven patients.

In addition to the rather dramatic reduction in relapse following the conservative surgical procedure which was employed in this investigation, there mere other advantages to this procedure over the more classic excision-type frenec- tomies and gingivectomies. In forty-five of the patients who underwent the surgical procedures there was no loss of tissue in the interdental papilla area. In the two cases which did show minimal loss of interdental gingival margin (Fig. 6), the mesiodistal dimensions of the incisal edges of the central incisors were exces-

500 Edwards Am. J. Ol‘thod. Mazl1977

Fig. 6. Some loss of marginal interdental papilla following surgical procedure.

sively large when compared to the cervical dimensions (triangular crowns) ; thus, the interdental area available for the gingival papilla was rather extensive and very pyramidal in shape. Both cases had required a gingivoplasty to recontour the excess gingival “pile-up” in the interdental area following orthodontic closure of the diastema. Apparently, the very sharp pyramidal configuration of the interdental marginal gingiva necessary to fill the interdental spaces in these two cases was not compatible with the physiology of the gingiva ; thus, the interdental margin receded from the narrow apex of the interdental space. In none of the patients was there a scarring effect on the gingival or mucosal tissue from the surgical procedure.

The labial gingivoplasty was required in 17 per cent of the cases to recontour excessive amounts of gingiva after tliastema closure, but only 7 per cent of the cases required gingival contouring of the palatal interdental tissue. The CSF procedure around the four maxillary incisors was deemed necessary in four cases in which tight contact between the incisors was not achieved and in three cases which demonstrated pretreatment malrotations.

In all of the forty-seven patients the frcnal insertion was positioned more apically following surgical intervention. Thus, the zone of attached gingiva from the interdental margin to the frenal insertion was increased by granulation of attached gingiva from the midline area which had been surgically denuded of periosteum (Fig. 7). Although neither the palatine papilla nor the labial interdental papilla was excised in any of the cases, there wcrc no clinical signs (gingival retraction or tissue blanching when the lip was stretched) of frenal involvement with the gingival papilla following surgical intervention.

Surgical dressings were not placed following the periodontal surgery, since hemorrhage was not a problem (usually stopping completely in 3 to 5 minutes) and patient discomfort was minimal for the first day postoperatively and negligible thereafter. Hematoma in the mucosa or upper lip tissue did not occur in any of the patients. Clinical healing was observed to occur within 5 to 8 days, wit.h epithelization of the new midline attached gingiva being completed in 2 to 3 weeks. There was no occurrence of secondary infection in the surgical area.

The pretreatment radiographs showed a vertical cleft or ‘notch in the margin of the interseptal bone in forty-eight of the fifty-two diastema patients (92.3

Volume 71 Number 5 Diastema., frenum, frenectomy 501

Fig. 7. A, Preoperative view showing low insertion of frenum into interdental papilla. 8, Postoperative view. Note repositioning of frenum with increased zone of attached gingiva. C, Preoperative view showing large “fan-shaped” frenum attaching into area of gingival margin. D, Postoperative photograph showing repositioning of frenal tissue by surgical procedure.

per cent). Of the five patients whose orthodontically closed diastemas did not show a relapse potential, only one demonstrated the vertical bone cleft on the pretreatment radiograph, and the cleft was not evident on the posttreatment film. Not one interseptal cleft persisted in the experimental group whose relapse was negligible or less than 1 mm. following surgical intervention (Fig. 8). Two of the three cases which relapsed more than 1.5 mm. after the surgical procedures still demonstrated the vertical interseptal bone cleft.

Discussion8

Although the sample in Study A was not of sufficient size for one to derive statistically significant correlations with the total population, it is obvious that not every excessively wide band of frenal tissue located too near the gingival margin will cause, or even be associated with, a maxillary midline diastema. More than 20 per cent of the cases were observed to have no diastema but were judged to have an “abnormal” frenum. Likewise, more than 9 per cent of the patients demonstrating diastemas seemed to have noncontributory or “normal” frenums. It is also interesting to note the relative consistency between Studies A and B with respect to the percentage of patients showing diastemas but being classified as possessing normal (noncontributory) frenums (9.7 per cent in Study A and 8.6 per cent in Study B).

Some of the observations between the relapse tendencies of diastemas and the

502 Edwards

Fig. 8. A, Pretreatment diastema with “abnormal frenum.” B, Note osseous interdental

cleft between central incisors of preoperative diastema. C, Osseous cleft persisted following

orthodontic closure of diastema. D, Repositioned frenum and increased zone of attached

gingiva following surgical procedure. E, Apparent elimination of osseous cleft following

dissection of collagen fibers in transseptal cleft area.

midline frenums in Study B are especially noteworthy. Since the study showed that, approximately 28 per cent of the diastemas relapsed between 0.5 and 1.5 mm. regardless of whether there were abnormal or normal frenums prior to treatment, it is interesting to note that, if the patients who showed minimal relapse are discounted, 10 per cent of the diastemas associated with normal-appearing frenums did relapse more than minimally and that 16 per cent of the diastema cases with abnormal frenums showed negligible relapse tendcncics.

There are, of course, two obvious hypotheses to explain such data. If 10 per

cent of the diastema cases with “normal-appearing” pretreatment frenums were observed to relapse, it can be argued that possibly the frenal tissues were indeed the etiologic factors, but we were unable to clinically recognize the frenums in these cases as being truly “abnormal” and contributory to diastema relapse. In- disputably, the most flagrant weakness in this investigation has, to do with the subjective and arbitrary methods now available to differentiate the maxillary midline frenums as being “normal” or “abnormal.” Second, if 16 per cent of the diastema patients with clinically abnormal-appearing frenums show no relapse tendencies, there may indeed be a physiologic means by which aberrant frenal tissue can reorganize or readjust following the closure of a diastema. Certainly, if a large frenum between two separated central incisors in a 6-year-old child can physiologically adapt to the spontaneous closure of the diastema as the other anterior teeth erupt, there is no apparent reason why the same type of large frenum cannot adapt by some physiologic process to an orthodontically closed diastema in an older child or adult. The work of Ten Cate and colleaguesZ5 on the dual ability of the fibroblast to simultaneously degrade and synthesize collagen lends credence to such a supposition.

Nevertheless, the vast majority (about, 80 per cent in Study A and 91 per cent in Study B) of patients with maxillary midline diastemas were observed to have abnormal or aberrant frenums. Although it is certainly tempting, one must realize that such an observation cannot be construed to demonstrate a direct cause-and-effect relationship between an “abnormal” frenum and a midline diastema. In any case, the highly successful results shown in Study C toward reducing the reopening of orthodontically closed diastemas by the surgical elimination of any relapse potential in (1) the transseptal fibers, (2) the excessive interdental gingival tissue, and (,3) the frenum would show, at least indirectly, that such soft tissues do play a significant role in diastema relapse.

The surgical technique outlined in this study comprised three separate procedures: (1) apical repositioning of the frenum (frenotomy) with denudation of alveolar bone, (2) destruction of the transseptal fibers between the approximated central incisors, and (3) gingivoplasty or rccontouring of the labial and/or palatal gingival papillae in cases of excessive tissue accumulation (Fig. 9). The frenotomy is basically an operation designed to sever the frenum by incising it from its apex toward the base. However, it should be recognized that the frtnot- omg procedure used in this study is a localized gingival-extension operation. The wound resulting from the frenot,omy incisions is triangular in shape. Conse- quently, it is bound on two sides by a fixed tissue (att,ached gingiva) . The gingiva which comprises the two sides of the triangle provides lateral fixation for the granulation tissue bed ; therefore, the granulation tissue differentiates into gingiva or a fixed scar, which is functionally equivalent to att,ached gingiva.F. I2 Conversely, granulation tissue which is not immobilized by a fixed tissue (gingiva) laterally, will differentiate into alveolar mucosa instead of attached gin-

. 12 giva. The periodontic, literature has stated that it makes little difference in the

therapeutic result whether the frenotomy incisions are made to bone in order to denude the alveolar plate or whether the incisions partially penetrate the alveolar

504 Edwards Am. J. Orthod. May 1977

Fig. 9. A, Preoperative view of diastema and frenum. B, Frenum and excess accumulation of gingiva following orthodontic closure of diastema. C, initial incisions to excise frenal tissue. Note “ballooning” effect in mucosal tissue from anesthetic infiltration. D, Excision

of frenum from mucosal tissue. E, Denudation of alveolar bone. F, “Destruction” of trans- seotal fibers.

mucosa so that the bone remains covered.‘” It has been stressed that the therapcu- tic result (a, desired increase in the zone of attached gingira) is not dependent on whether bone is denuded (stripped of its periosteum) but, rather, on the lack of mobility of the granulation tissue that covers the ~vo~mtl.

Nevertheless, in the performance of a frenotomy for the alleviation of relapse of orthodontically closed diastemas, the removal of the pcriosteum under the cx- cised portion of the frenum is advocated in an attempt to remove the elast,ic fibers of the frenum which have been shown to penetrate the periosteum.16 Such elastic fibers have not been demonstrated to adversely affect the increase in attached

Volume 71 Number 5 Diastema, frenum, frenectomy 505

Fig. 9 (Cont’d). G, Removal (gingivoplasty) of excess interproximal gingiva tissue. H, Photo- graph taken immediately following surgical procedure. Placement of surgical dressing not indicated. I, Twenty-four hours after operation. J, Ten days after operation. K, Three weeks after operation. 1, Three months out of retention. Note definite apical repositioning of frenal attachment with resulting increase in zone of attached gingiva.

gingiva following a frenotomy ; nor have they been shown to adversely affect the alleviation of relapse in diastema cases. However, if the purpose of the surgical procedure is to eliminate the undesira.ble frenal tissue and to establish a normal interdental soft-tissue anatomy, it is seemingly important to remove the elastic fibers impregnating the periosteum underlying the frenum, since nowhere in the normal human periodontium is there an elastic tissue involvement Gith attached gingiva.

Although it is debatable to what extent the transseptal fibers reorganize and adapt to a normal anatomic configuration following the orthodontic approxima-

506 Edwards izm. J. Orthod. May 1977

tion of the two teeth adjacent to an extraction area, it is important that these fibers be surgically eliminated after orthodontic closure of a diastema. The orthodontic closure of an extraction site and the closure of a diastema affect the transseptal ligament differently. It has been observed that upon final closure of an extraction site and the approximation (paralleling) of the root structure of the adjacent teeth, the more apical transseptal fibers appear relatively normal in histologic sections.!’

Theoretically, such an adaptation by the transseptal fibers was possible only after destruction of the compressed and convoluted fibers by ischemia following the final approximation of the teeth.” Moreover, it has been shown that extraction sites reopen (relapse) less often in cases where the dental roots have been approximated than in cases where the roots have been left diverging.l”, 21 The orthodontic closure of a diastema intentionally involves positioning the root structures in a diverging pattern; thus, the transseptal fibers are never compressed to a degree where possibly the blood supply would be interrupted and the fibers destroyed. Indeed, Campbell and his associates” demonstrated a very abnormal and convoluted histologic pattern to the transseptal fibers after orthodontic closure of diastemas.

It also is not sufficient merely to transsect the transseptal ligament, as is done in eliminating a rotational relapse potential in the supracrestal fibers, since the total interruption of the transseptal ligament is required before a new and functionally adapted ligament can be formed. In fact, the disruption of the transseptal fibers (without a frenotomy) would be the sole surgical procedure indicated in the case of a diastema with no associated aberrant frenum. Other researchers have observed that only a 30-day period is sufficient for the formation of a completely new transseptal ligament after dissection.”

The high correlation shown in this study between the existence of a vertical osseous cleft in the interseptal bone and a diastema problem which is prone to relapse would substantiate the work of Bray.4 It is certainly intriguing to specu- late that the attempted removal of all soft tissue (presumably, residual frenal fibers) in these interseptal clefts resulted in t,he osseous fill-in of the cleft and a further reduction of the relapse phenomenon.

In approximately one-fifth of the experimental cases, it was deemed necessar) to recontour (gingivoplasty) the labial and/or palatal interdental areas where an excess of gingiva had accumulated during orthodontic closure of the diastemas. In earlier studies it has been shown tha,t the apparent inability of a tooth to be moved through the supporting gingival tiwue results in this accumulation of excess interproximal gingiva. The removal of such tissue (but without complete removal of the interdental papillae) is advocated in attempting to reduce diastema relapse since such a procedure was demonstrated to improve the stability of orthodontically approximated teeth in extraction cases.!’

The CSF (circumferential supracrestal fiberotomp) procedure, which was initially intended to prevent relapse of orthodontically rotated teeth,s was not used in this study as a means of allcviatin g the reopening of orthodontically treated diastemas (unless there were malrotations or slight interdental spaces between the central and lateral incisors), since it was concluded that the major

Volume 71 Number 5

relapse potential was the compressed supracrestal soft tissue between the central incisors and not the possibility of temile forces distal to the central incisors after the six anterior teeth were in tight approximation.

Moreover, the efficacy of the surgical procedures described in this study was not compared to other techniques for the reduction of diastema relapse. It was thought that if the surgical procedures of this study were found to be effective in alleviating the relapse phenomenon in diastema cases, the periodontal advantages inherent in them would make comparisons with the other excision-type techniques unnecessary.

In summary, although the surgical techniques examined in this study have apparently shown a dramatic benefit in reducing the problems of relapse in diastema situations, they were not effective in 100 per cent of the patients. Also, the orthodontists’ apparent inability to differentiate clinically between the diastema ease which will relapse because of an “unadaptable” frenum and the case which will remain stable renders surgical intervention necessary in all diastema cases, unless the patient and the clinician are willing (1) to retreat those cases which relapse and then surgically adjust the frenal and/or interdental tissues to help alleviate the relapse tendencies or (2) to surrender to a regimen of fixed and permanent retention in the majority of diastema problems.

Conclusions

1. The pretreatment relationship betlveen a clinically “abnormal’‘-appearing maxillary midline frenum and a midline diastema showed a strong, but not absolute, correlation. A certain percentage of patients demonstrated (1) a diastema hut not an “abnormal” frenum or (2) no diastema but an “abnormal” frenum.

2. Diastema cases in which there were “abnormal” pretreatment frenums dcm- onstrated a decidedly stronger potential for relapse after orthodontic closure. The exceptions to the rule were explained by the clinician’s inability to diffcren- tiate between “normal” and “abnormal” frenums and by the periodontium’s apparent (if not consistent) ability to reorganize the frenal and interdental tissues following orthodontic tooth movement.

3. A three-stage surgical procedure was shown to be very effective in alleviating the relapse phenomenon following orthodontic treatment of diastemas. The surgical procedures were successful in avoiding many of the hazards to the periodontium associated with previous techniques.

REFERENCES 1. Archer, W. H. : Oral surgery; a step-by-step atlas of operative techniques, ed. 3, Phil-

adelphia, 1961, W. B. Saunders Company, pp. 192198. 2. Baum, A. T.: The midline diastema, J. Oral Med. 21: 30, 1966. 3. Bell, W. H.: Surgical-orthodontic treatment of interincisal diastcmas, AM. J. ORTIIOIL 57:

158-163, 1970. 4. Bray, R. J.: The maxillary midline diastema, presented hefore the American Association

of Orthodontists, New York, N. Y., 1976. 5. Campbell, P. M., Moore, J. XV., and Matthews, J. L.: Orthodontically corrected midline

diastemas, Ahr. J. ORTHOD. 67: 139-158, 1975.

6. Carraro, 5. J., and Carranza, F. A.: Effect of removal of periosteum on post-operative results of mucogingival surgery, J. Periodontol. 34: 223-226, 1963.

508 Edwards Am. J. Orthod. Mau 1977

7. Dewel, B. E’. : The normal and the abnormal labial frenum: Clinical differentiation, J. Am. Dent. Assoc. 33: 318-329, 1946.

8. Edwards, J. Cr.: A surgical procedure to eliminate rotational relapse, AM. J. ORTHOD. 57: 33-46, 1970.

9. Edwards, .J. G. : The reduction of relapse in extraction ~~:Px~s, AM. J. ORTHOU. 60: 12% 141, 1971.

10. Ewcn, S. J., and Pasternak, K. : Periodontal surgery-An adjunct to orthodontic therapy, Periodontics 2: 162-l 71, 1964.

11. Finn, S. B.: Clinical prdodontics, Pl~il:tdell~hix, 1973, \V. H. Saunders Company, pp. 416. 418.

12. Friedman, N., and Levine, H. L.: Mucogingival surgery, J. Periodontol. 33: 14-35, 1964. 13. Frisch, J., Jones, R., and Bhaskar, S. N.: Conservation of maxillary anterior aesthetics: .I

modified surgical approach, J. Periodontol. 38: 11-17, 1967. 14. Gibbs, S. L.: The superior labial frenum and its orthodontic consideration, N.Y. Statr

Dent. J. 34: 550, 1968. 15. Hatasaka, H. H.: A radiographic study of roots in extraction sites, Angle Orthod. 46: 64-

68, 1976. 16. Henry, S. W., Lcvin, IM. P., and Tsaknis, P. J. : Histologic features of the superior labial

frenum, J. Periodontol. 47: 25-28, 1976. 17. Horowitz, S., and Hixon, E. H.: Physiologic recovery following orthodontic treatment,

AN. J. ORTHOD. 55: 1-33, 3969. 18. Knox, L. B., and Young, H. C.: Histological studies of the labial frenum, I.A.D.R. pro-

gram and abstracts, 1962. 19. Kale, H.: Surgical operations on the alveolar ridge to correct occlusxl abnormalities, Oral

Surg. 12: 515.529, 1959. 20. Kruger, G. 0.: Oral surgery, ed. 2, St. Louis, 1964, The C. V. Mosby Company, pp. 146.74i. 21. Parker, G. R. : Transseptal fibers and relapse following bodily retraction of teeth: A his-

tologic study, AM. J. ORTHOD. 61: 331-334, 1972. 22. Skogsborg, C. : The use of septotomy (surgical treatment) in connection with orthodontic

treatment, and the value of this method for proof of Wolkoff’s theory of tension of the bone tissue after the regulation of teeth, INT. J. ORTHOD. 18: 1044, 1932.

23. Sicher, H.: Orban’s oral histology and embryology, ed. 7, St. Louis, 1962, The C. V’. Mosby Company, p. 260.

24. Taylor, J. E.: Clinical observation relating to the normal and abnormal frenum labii su- perioris, AM. J. ORTHOD. ORAL ST-RG. 25: 646-650, 1939.

25. Ten Cate, A. R., Deporter, D. A., and Freeman, E.: The role of fibroblasts in the remodeling of periodontal ligament during physiologic tooth movement, AX. J. ORTHOD. 69: 155 167, 1976.

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Documents

Edwards 1977 Diastema and Frenum