Case Report

Guided tissue regeneration in managing an incisorwith a labially fused supernumerary: case reportBernadette K. Drummond, BDS, MS, PhD, FRACDS Douglas W. Holborow, BDS, FDSRCSNicholas P. Chandler, BDS, MSc, LDSRCS, FDSRCPS, FDSRCS, FFDRCSI

S upernumerary teeth occur most commonly in themaxillary anterior region. When in the midlinearea, such a tooth is commonly referred to as a

mesiodens with most remaining unerupted.1, 2 Theprevalence of supernumerary teeth is reported to befrom I to 3%.3‘4 Supernumerary teeth may cause or berelated to over-retention of primary teeth, impaction,or ectopic eruption of nearby permanent teeth, andabnormal development or root resorption of adjacentteeth2 Most commonly, a mesiodens is located betweenor palatal to the central incisors. Very few are locatedlabially. ~ Uncommonly, supernumerary teeth maybe fused to normal teeth in the arch, most frequentlyby lateral fusion, s-7 Problems associated with thistype of fusion include poor esthetics, crowding,abnormal eruption, residual periodontal defects, anddifficulty managing the tooth to which the supernu-merary is fused.

When a supernumerary tooth is fused to a normaltooth in the lateral position, spacing may be a problemin the arch and has usually indicated the removal of thesupernumerary. The fusion may involve the rootcementum only or also the root and crown dentin and/or enamel, with separate or communicating root canals.When the fusion occurs palatally or labially, there alsomay be problems with the occlusion, repair of a bonydefect, and/or the attached gingiva.

Removing a fused tooth presents several difficulties.Healing may result in the formation of a pocket or along junctional epithelium. In teeth with fused crownsand roots, this has sometimes been avoided by the se-quential removal of the fused root and later the crown.8

The fused portion also may be removed in one proce-dure by sectioning.8,9 To achieve a new attachment, thegingival tissues must be excluded from the root sur-face.1°," However, bone-derived granulation tissuemay lead to ankylosis and root resorption, while granu-lation tissue derived from gingival connective tissuemay result in root resorption.5

Guided tissue regeneration allows the regenerationof normal periodontal attachment to the root surface

where surgery has created communication of that sur-face with gingival epithelial and connective tissues.Preventing apical migration of gingival epithelial tis-sues and contact of the gingival connective tissue withthe root surface after surgery allow establishment ofperiodontal ligament cells on the root surface.12,13

Case reportA 9-year-old Caucasian male was referred to the

University of Otago School of Dentistry. The medicalhistory was noncontributory except for mild asthmacontrolled by a VentolinTM (Glaxo -- Edinburgh Phar-maceuticals, Palmerston North, New Zealand) inhaler(salbutamol) on demand. General and dental develop-ment were normal for his chronologic age and he wasreceiving routine dental care from a community schoolclinic. The reason for referral was a supernumerarytooth labially positioned over the erupted maxillary leftpermanent central incisor. On attempted extraction ofthe supernumerary, the permanent tooth also hadshown movement, suggesting fusion of the two teeth.

Oral examination

The extraoral and intraoral soft tissues were normaland oral hygiene was moderately effective. The denti-tion was in the early to middle mixed stage with a ClassI molar relationship on both sides. There was a 50%overbite and an overjet of 4 mm. The anterior teethwere not crowded and the maxillary anteriors werecompletely erupted. The teeth had no caries or resto-rations. The supernumerary tooth was partiallyerupted labial to the maxillary left central incisor (Fig1). Dental floss could only be manipulated to the gin-gival level between crowns suggesting fusion.

Radiographic examination

A panoramic radiograph was exposed to check den-tal development and to look for missing teeth or otherdental abnormalities. This confirmed that all permanentteeth except the third molars were present and devel-oping normally. In the anterior region, a tooth was su-perimposed over the maxillary left permanent central

368 American Academy of Pediatric Dentistry Pediatric Dentistry - 17:5, 1995

Fig 1. Anterior view of maxillary left permanent centralincisor with a labially erupted supernumerary tooth.

1^______________________________^^^^E___J

Fig 2. Periapical radiograph of maxillaryleft permanent central incisor and labialsupernumerary tooth.

incisor. Periapical, occlusal, and lateral radiographs alsowere exposed to determine the presence of separate rootcanals and the level of fusion (Fig 2). Although thereappeared to be two root canals, the radiographs did notallow determination of their degree of communication.

TreatmentBecause removing the supernumerary tooth would

create a significant bony dehiscence with exposure ofthe root surface of the maxillary left central incisor, aguided tissue regeneration procedure to promote nor-mal periodontal tissues was planned. Placement of theguided tissue regeneration membrane after removingthe supernumerary tooth is shown schematically in Fig3. Because of the possible root canal communication,endodontic surgical procedures were included in theplanning. The procedure was carried out under gen-eral anesthetic with local anesthetic infiltration (3%Citanest™ [Astra Pharmaceuticals, North Ryde, Aus-

tralia] with Felypressin™) as requested by the anesthe-tist to provide control of local pain and bleeding. Agingival crevicular incision was made from thedistal of the right lateral incisor to the distal of the leftlateral incisor where a releasing incision was made. Afull-thickness flap was raised revealing the fused su-pernumerary tooth with two-thirds of its root devoidof alveolar bone. The apical level of fusion could notbe determined visually or by probing, but the shapeof the visible portion suggested fusion of cementumand dentin only.

A straight surgical bur was used with slow speed andsaline coolant to section the crown of the supernumer-ary at the level of the cementoenamel junction (CEJ).The crown separated cleanly, revealing the roots fusedfrom this level. The width of the fusion was approxi-mately 6 mm. Continuing a sweeping motion aroundthe curve of the permanent tooth root with the straightbur, the two teeth were gradually separated taking careto avoid removing lateral bone or damaging the surfaceof the root adjacent to the fusion. At the level of separa-tion, 10 mm below the CEJ, the root canals did not com-municate, although the canal of the supernumerarytooth was exposed along a deep palatal groove (Fig 4).

The full extent of the bony dehiscence was clearlyvisible (Fig 5). A patch of Gore-Tex™ Teflon (GoreAssociates, Flagstaff, AZ) membrane was cut and

membrane-~

-cut surface

Fig 3. Diagram of guided tissue regeneration membraneplacement. The left shows a labiopalatal cross section ofthe fused teeth. The right shows the membraneplacement after removal of the supernumerary tooth. Thespace below the membrane is expected to fill with bone,which will attach to the cut surface of the tooth byperiodontal ligament and cementum.

Fig 4. The supernumerary tooth showing the palatalgroove along the root.

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Fig 5. View of the maxillary left permanent central incisorshowing the degree of bone dehiscence after surgicalremoval of the supernumerary tooth.

Fig 7. Appearance of the dehistence area over the maxil-lary left permanent central incisor when the flap wasraised after 6 weeks to allow removal of the membrane.

Fig 6. Maxillary left permanent central incisor with apatch of Core-Tex Teflon membrane covering the bonydefect over the root.

shaped to cover the residual bony socket's lateral edges.This was sutured in place using Gore-Tex sutures (Fig6). The flap was replaced over the membrane and su-tured with 4-0 black silk sutures. Postoperative painwas controlled with oral paracetamol and recovery wasuneventful. The silk sutures were removed after oneweek. A flap was raised to enable the membrane to beremoved after 6 weeks. Granulation tissue filling thebony defect was clearly evident (Fig 7).

Four weeks after surgery, the maxillary central in-cisors suffered trauma in a playground accident. Bothteeth showed normal color and mobility, and were vi-tal to cold and electric pulp testing. Radiographs re-vealed no abnormalities. Followup has been at 3-monthintervals to check the periodontal healing and to evalu-ate the condition of the traumatized teeth. At thepresent time, 30 months after surgery, there is a verynarrow 4-mm pocket with 3 mm of periodontal attach-ment loss. Crevice depths around the remainder of thetooth are 2 mm with no associated attachment loss.There has been 7 mm of attachment gain in the origi-nal 10-mm defect. The color of the tooth remains accept-

Fig 8. Appearance of maxillary left permanent centralincisor 18 months after the surgical removal of a labiallyfused supernumerary tooth and the repair of the bonydehiscence using guided tissue regeneration.

able but its vitality is in question as it does not respondto cold testing (Fig 8). Nevertheless the root apex hasshown continued closure (Fig 9), and there are no otherabnormal signs or symptoms. The tooth is now moni-tored at 6-month intervals.

DiscussionManaging this case presented several treatment di-

lemmas, the first being the surgical removal. Becausethe roots of the teeth were not surrounded by bone (asin past reports of laterally fused teeth), it was not pos-sible to carry out a two-stage procedure to achieve pe-riodontal healing.5-14 Surgery was uncomplicated butresulted in a labial bony dehiscence. In the past thiswould have been expected to heal with a long junc-tional epithelium and without the reformation of labialbone. It was also important to preserve an acceptableband of labially attached gingiva.

A guided tissue regeneration technique providedthe greatest likelihood of regenerating normal tissuesand attachment. This technique has been successful intreating bone loss from periodontal disease15 and for

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Fig 9. Radiographic appear-ance of maxillary left perma-nent central incisor 18 monthsafter surgical removal of alabially fused supernumerarytooth showing continued rootgrowth and apex closure.

ridge augmentation.16

It is not possible tostate unequivocallythat regeneration of anew periodontal at-tachment has oc-curred, but other re-ports indicate thatthis is likely,17 and 7mm of attachmenthas been gained 30months after surgery.

The second di-lemma was the tim-ing of the procedure.Some authors advo-cate early removal toprevent orthodonticproblems and morecomplicated sur-gery,1' 18 while otherssuggest waiting untilroot development ofthe permanent inci-sors is complete toprevent damage tonerve or blood sup-plies.19 In this case, surgery was delayed 9 months frominitial presentation to maximize the success ofendodontic therapy if required. Had the teeth shareda common canal near the apex, endodontic treatment(including any necessary surgery) would have beenincluded in the management. With the favorable bonyhealing, future endodontic therapy should present noproblems if a surgical approach is required, since thetooth has demonstrated continued root closure whileits vitality remains under review.

This case demonstrates the application of guidedtissue regeneration principles during surgery in thedeveloping dentition. The long-term survival of themaxillary left central incisor was compromisedperiodontally and esthetically because of the presenceof a long bony dehiscence associated with the labiallyfused supernumerary tooth. Healing has been success-ful so far and if problems develop, the alveolar bonewill not have been compromised and will allow sev-eral treatment options.

Dr. Drummond is a senior lecturer and a specialist in pediatric den-tistry; Dr. Holborow is a senior lecturer and a specialist inperiodontology; and Dr. Chandler is a senior lecturer and a spe-cialist endodontist, School of Dentistry, University of Otago,Dunedin, New Zealand. Reprint requests should be sent to Dr.

Bernadette K. Drummond, Department of Community DentalHealth, University of Otago School of Dentistry, PO Box 647,Dunedin, New Zealand.

The authors acknowledge the contribution of illustrator Mr P.Tilson.

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