dt_aug10_127_fnl

Continuing Education

Restorative Managementof Double Teeth:

Two Case ReportsAuthored by Howard E. Strassler, DMD; Sy Majidi, DDS;

Eric Levine, DDS; Kristin Harvey, DDS

Course Number: 128

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LEARNING OBJECTIVESAfter reading this article, the individual will learn:• The etiology and clinical presentation of double teeth.• Treatment techniques for double teeth.

ABOUT THE AUTHORSDr. Strassler is professor, Division ofOperative Dentistry, Department of Endo-dontics, Prosthodontics and OperativeDentistry, University of Maryland DentalSchool, Baltimore, Md.He can be reachedvia e-mail at [email protected].

Disclosure: Dr. Strassler reports no conflicts of interest.

Dr. Majidi maintains a private practice in pediatric dentistryin Washington, DC and McLean, Va. He can be reached viae-mail at [email protected].

Disclosure: Dr. Majidi reports no conflicts of interest.

Dr. Levine is assistant professor, Division of OperativeDentistry, Department of Endodontics, Prosthodontics andOperative Dentistry, University of Maryland Dental School,Baltimore, Md. He can be reached via e-mail [email protected].

Disclosure: Dr. Levine reports no conflicts of interest.

Dr. Harvey is in Advanced Education in General Dentistry,Veterans Affairs Hospital, San Antonio, Tex. She can bereached via e-mail at [email protected].

Disclosure: Dr. Harvey reports no conflicts of interest.

INTRODUCTIONTooth anomalies due to developmental disorders of teethcan be responsible for variations in size, shape, toothnumber, missing teeth, and tooth structure due to enamel ordentin malformation.1 These defects in tooth developmentcan be related to hereditary, systematic, or local factors, orcan be idiopathic. Patients with ectodermal dysplasia canexperience missing and malformed teeth. Gene mutationsresponsible for structural changes in enamel and dentinresult in amelogenesis imperfecta and dentinogenesisimperfecta, respectively.1-3

A disturbance that occurs during tooth development(eg, trauma to the primary anterior teeth) can affect thedeveloping structure of the underlying permanent tooth’senamel, leaving the developing tooth with either colordiscrepancies (enamel hypoplasia) or malformations to theenamel surface. In some cases patients may experiencecongenitally missing teeth or supernumerary teeth. Amongthe most common dental malformations are undersized,peg-shaped maxillary lateral incisors.

A tooth bud is made up of cells derived from the ectodermof the first brachial arch and the ectomesenchyme of theneural crest.4 During tooth development, there can be primarydevelopmental deviation of the teeth whereby a “double tooth”forms. The terms “double teeth,” “joined teeth,” “fused teeth,”and “twinning” typically describe 3 distinctly different types ofmalformations that alter the appearance of teeth: gemination,fusion, and concrescence.5-8

This article discusses the etiology and clinicalpresentation of double teeth, and presents 2 case reportsdescribing treatment for double teeth.

TYPES OF DOUBLE TEETHGemination appears as 2 crowns sharing the same root,with a characteristic shallow groove along the facialsurface.8-10 Fusion is the combination of 2 tooth budsduring development, producing a double tooth. The fusionmay involve the entire length of the tooth or the roots only.8-12

In both instances, the appearance is of one tooth that isunusually wider than normal. Concrescence is a type offusion of the teeth where 2 adjacent teeth are joined at thecementum. Radiographically, these teeth are 2 distinctlydifferent teeth that are fused on the root surface.


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While the etiology of double teeth is still not known,trauma during tooth development, hereditary predisposition,and environmental factors have been suspected. Amongenvironmental factors, fetal alcohol exposure, thalidomideembryopathy, and hypervitaminosis have been described.13-17

Syndromes commonly associated with double teeth areachondroplasia, focal dermal hypoplasia, osteopetrosis, andchondroectodermal dysplasia.13 It has been reported thatthe frequency of gemination or fusion for the primarydentition can range from 0.4% to 0.9%, and for the adultdentition 0.2%.13,15 It is very rare to see bilateral doubleteeth. The prevalence of double teeth has been reported tobe very rare (less than 0.05%).6,7

Gemination is a rare anomaly that arises when the toothbud of a single tooth attempts to divide to form 2 teeth.Gemination more frequently affects the primary teeth, but itmay occur in both primary and permanent dentitions,usually in the incisor region.16,17 The clinical appearance ofgemination is either 2 completely or incompletely separatedcrowns with a single root and root canal. It has beenreported that complete separation of the crowns can occur(2 teeth from one tooth bud).18,19 Geminated teeth aretypically disfigured in appearance due to irregularities of theenamel, leaving deep invaginations on the facial or lingualsurfaces. These invaginations are susceptible to caries andcan be precursors to isolated periodontal problems.16,20

Gemination is confirmed clinically when the number of teethper quadrant is normal.

Fusion is a developmental anomaly in tooth morphologywhich may be due to either joining of 2 separate tooth buds orthe partial separation of a single tooth bud. Fusion isunderstood to occur during the developmental stages ofinitiation through morphodifferentiation.4 Several instances offusion in a single family have been reported, suggesting ahereditary pattern.5,18 This single tooth may appearabnormally large or may have a bifid crown or roots. Patientswith tooth fusion often have fewer than the full complement ofteeth within the arch if the fused tooth is counted as a singletooth. It is not unusual for a fused tooth to have 2 separate rootcanals.18,21 Fusion may occur between a normal tooth and asupernumerary tooth such as a mesiodens or a para molar.22

Fused teeth may show unusual configurations of their pulpchambers, root canals, or crowns.Fusionmay be differentiated

from germination by a reduced number of teeth. Anexception is in the unusual case in which the fusion isbetween a supernumerary tooth and a normal tooth. Theinfrequent occurrence of these cases along with its complexcharacteristics often make it difficult to treat.5,18,23

DIAGNOSIS AND TREATMENT OF DOUBLE TEETHTreatment may be based upon the type and morphologicalvariation of fused and geminated teeth. Double teeth in theposition of the maxillary central incisors have significantaesthetic and size concerns when compared to theiradjacent contralateral incisor. Restoration of double teethcommonly involves endodontic, orthodontic, andperiodontal treatment.6,18,22-28 The potential clinicalproblems associated with fusion include an abnormalshape of the tooth and overall space discrepancies, whichmay eventually lead to periodontal disease.

The separation of fused teeth is another viable treatmentoption that does carry some risk. Where fused teethmaintain separate roots with no communication between thedental pulp of each tooth, hemisections have beensuccessfully performed without endodontic treatment.Complications to hemisection include hypersensitivity,irreversible pulpitits, and external root resorption.6,18,20,28-30

One case report has described an extraction of a fusedmaxillary central incisor and mesiodens, separation of theteeth, and finally, reimplantion of the central incisor.23 Incases of gemination or fusion where there are aestheticconcerns and no underlying risk factors, conservative use oftooth reshaping, direct composite bonding, bondedporcelain veneers, and crowns have been described.4,23,29

Definitive diagnosis for double teeth can sometimes bedifficult to make. The criteria to differentiate gemination andfusion are morphology, anatomy, jaw location, crowding, andnumber of teeth. In cases of gemination there may be asingle crown with an appearance of 2 coronal halves.Fusion appears to have an angled, crooked appearance.Fused teeth can have a double pulp space that may or maynot communicate, although a single pulp space is alsopossible. Gemination typically only has a single large pulp.Double teeth in the mandible are most likely due to fusion, butwhen in the maxilla, gemination is more probable. Spacingand crowding is characteristic of double teeth.The fusion of 2


2

Restorative Management of Double Teeth: Two Case Reports

teeth together tends to leave spaces since the fused toothtakes up less space than 2 separate teeth. A single tooth thathas budded into 2 is likely to cause crowding.Traditionally, thenumber of teeth in the quadrant has been used to distinguishbetween fusion and gemination.When a tooth is missing, it isassumed fusion occurred. When all teeth are present in thequadrant, and a double tooth is present, then gemination ismore likely. Since the histology during tooth developmentdetermines the diagnosis, for many cases it is impossible todefinitively differentiate between fusion and gemination withoutwitnessing the growth of the tooth germ on a histological scale.No matter whether the diagnosis is gemination or fusion,evaluation for treatment is not affected by etiology, rather by theclinical conditions present and prognosis of treatmentoutcome.Tooth morphology of double teeth can put the patientat a higher risk for dental caries and periodontal disease. Inthese cases operative care is used as a preventive measure toreduce both caries and periodontal risk.

The aesthetic restoration of double teeth depends uponthe patient’s desires. Unless there are increased risks toperiodontal health, caries, or occlusion, treatment is electivefor aesthetic reasons.16,20 Treatment choices to change theaesthetic appearance of a double tooth in the aesthetic zonecan include shaping the tooth to create a narrowerappearance. In these cases, many times the appearance ofthe width of the tooth at the gingival margin cannot bechanged, and for a patient with a high smile line, thedifference in width is still apparent. When enamel defectssuch as incisal edge notching are present, facialinvaginations where the tooth is joined deform theappearance of the tooth. Restorative treatment includingdirect aesthetic composite bonded restorations, porcelainveneers, and crowns can change the appearance of thetooth.5,23,29

CASE REPORT NO. 1: BILATERAL DOUBLE TEETHA 9-and-a-half-year-old patient was presented to the dentalschool clinic. The mother had brought her child to the dentalschool because of her concerns for the child’s large front teeth.The intraoral examination revealed a mixed dentition ofprimary and permanent teeth consistent with the child’s age. Itwas noted that the patient had 2 large and abnormally shapedmaxillary central incisors that had notched incisal edges

(Figure 1). The patient’s maxillary right lateral incisor wasmissing with no history of extraction of this tooth (Figure 2).There was no past family dental history of unusual toothanomalies or congenitally missing teeth.

As stated earlier in this article, “double teeth” is aninclusive description that groups gemination, fusion, andconcrescence together. All 3 conditions result in 2 teethstructurally combined at the root, crown, or cementum. Thedifferential diagnosis was based upon clinical appearance ofincisal edge notching, the presence of an invagination on thefacial surface of tooth No. 8, and radiographic findingsrevealing single root canals for both teeth Nos. 8 and 9. Also,the maxillary right lateral incisor was missing, and the leftmaxillary lateral incisor was present. A missing lateral incisorindicates the likely probability of fusion of teeth Nos. 7 and8. The presence of the left lateral incisor suggestsgemination of tooth No. 9. This is the most likely explanation


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Figure 1. Preoperative view of teeth Nos. 8 and 9 (double teeth).

Figure 2. Panorex demonstrating missing tooth No. 7 to help indifferential diagnosis of teeth Nos. 8 and 9.

of the clinical and radiographic findings, but otherpossibilities cannot be ruled out.

Two other possibilities can also explain this patient’s doubleteeth. Even though there was no family history of congenitallymissing teeth, tooth No. 7 may be congenitally missing andtooth No. 8 may have experienced gemination. If this is thecase, the patient has bilateral gemination of the maxillarycentral incisors. The third possibility is tooth No. 7 iscongenitally missing and tooth No. 8 is fused with a mesiodenssupernumerary tooth.Yet another possibility is that tooth No. 9may have fused with a mesiodens rather than experiencedgemination. It was decided that the most likely diagnosis wasfusion of teeth Nos. 7 and 8 and gemination of tooth No. 9.

The patient’s dental condition was not contributing to anyperiodontal problems, predisposition to caries, or occlusalproblems. From a radiographic evaluation the widthdiscrepancy between teeth Nos. 8 and 9 could be managedby tooth reshaping without encroaching on the pulp. Thegoal to have similar widths for teeth Nos. 8 and 9 wasdesirable. After width modifications it might be necessary tochange the incisal length; this would not be known until thetooth reshaping was accomplished. Another factor toconsider was to try and preserve the appearance of thedistal surface of tooth No. 8 to preserve some of the contourand height of contour on the distal surface. Preparation ofthe mesial surfaces of teeth Nos. 8 or 9 would be avoided toreduce unwanted increases in the diastema.

Two options of care were presented to the parent. Theoption of no treatment was presented, as the condition of themaxillary central incisors was not contributing to anypathology. A treatment option was presented to take aminimally invasive approach of tooth reshaping to reduce themesiodistal width of the central incisors to improve sizediscrepancy (Figure 3). Direct composite resin bonding wouldbe applied to reduce the vertical groove along the facialsurface. The conservative tooth reshaping and restorativeoption was chosen by the child’s parent as the best option ofcare. It was explained to the parent that while the appearanceof both maxillary central incisors would be improved, thecervical width of both incisors could not be changed. It wasalso explained that both central incisors had potential forfurther eruption that could increase the incisogingival length ofthe teeth.

It was determined for this procedure that there was noneed for local anesthesia, since all tooth preparation andshaping was in enamel only. Before any tooth preparation, theshade for the composite resin was selected using a ClassicVITA Shade Guide (Vident). The goal of tooth width reductionwas to equalize the widths of teeth Nos. 8 and 9. The widthsof both teeth were taken with a Dental Dial Caliper (Masel)and recorded.The distal surface of tooth No. 8 was contouredto reduce the width at the incisal third using a thin, finediamond with a high-speed handpiece with air-water spray.The determination for the amount of distal reduction of toothNo. 8 was the width of tooth No. 9 and the desire not toencroach on the height of contour on the distal surface oftooth No. 8.To accomplish this, the diamond in the handpiecewas angled from pure reduction of width following the longaxis of the distal surface, to slightly angle the tip of thediamond to preserve the height of contour and to create theperception and illusion that tooth No. 8 was the same widthas tooth No. 9. The enamel surfaces were then smoothedwith a needle-shaped, 10-bladed composite resin finishingbur (SE8-10 [SS White Burs]).

Following shaping of tooth No. 8, the facial surfaces andincisal edges of teeth Nos. 8 and 9 were lightly roughenedwith a medium grit diamond using a high-speed handpiecewith air-water spray. The teeth were etched for 15 secondswith a 37% phosphoric acid etchant and rinsed for 10seconds with an air-water spray, then dried. A fifth-generation adhesive (Septobond [Septodont]) was appliedto the teeth with a disposable brush (BendaBrush[Centrix]), then air was applied to the adhesive to thin theadhesive layer and to evaporate the solvent in the adhesive.The adhesive was light-cured for 10 seconds with a highintensity LED curing light (Allegro [Den-Mat]). A dimer-chemistry nanohybrid composite resin (N’Durance[Septodont]) was placed and shaped on both central


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Figure 3.Tooth No. 8 beforeshaping of the distalsurface to narrow thewidth of the tooth.

incisors using a plastic filling instrument (PFI AB1 Bogho-sian Composite Instrument [Hu-Friedy]), then light-curedfor 10 seconds. The composite resin was shaped withdisks (X-T Soflex [3M ESPE]) and polished with adiamond impregnated silicone disk (PoGo [DENTSPLYCaulk]). The child and mother were pleased with the finalresult (Figures 4a and 4b).

CASE REPORT NO. 2: UNILATERAL FUSION OF AMAXILLARY CENTRAL INCISORA 15-year-old male patient with an intact dentition except fora large maxillary right central incisor that had incisal notchingand a facial invagination was seen on consultation after thecompletion of orthodontic treatment (Figures 5a and 5b).Concerns by the adolescent and his mother for the size andshape of this large maxillary central incisor and what appearedto them as an undersized maxillary left central incisor requireda plan for the change in the aesthetic appearance of bothcentral incisors before an orthodontic retainer was fabricated.The diagnosis of gemination was made since the patient hadall his permanent teeth (Figure 6).

In the aesthetic analysis of this patient’s smile it was notedthat the patient displayed the gingival tissues when smiling.The width of tooth No. 8 at the gingival line precluded thechange in contours of the tooth so that anatomically the toothwould have a mesial and distal height of contour. This wasshown to the patient and his mother. The widths of teeth Nos.8 and 9 were taken, as well as the available space for anyaesthetic correction with direct bonded composite resin(Figure 7). Based upon the anatomic shape of tooth No. 8, itwas decided to reduce the width of that tooth at both themesialand distal incisal thirds and add composite resin to the mesialof tooth No. 9 to create an equal incisal third width for bothteeth. The patient and parent accepted this treatment plan.

Before initiating treatment, a shade was taken using aClassic VITA Shade Guide. To verify the shade selected, asmall amount of the universal nanohybrid composite resin(IPS Empress Direct [Ivoclar Vivadent]) was placed on thefacial surface of tooth No. 8 and light-cured.

The mesial and distal surfaces of tooth No. 8 werecontoured to reduce the width at the incisal third using a thin,medium grit diamond with a high-speed handpiece with air-water spray (Figures 8a and 8b).The width from the distal of


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Figures 4a and 4b.(a) Completedrestorative result afterreshaping—narrowingand restoration withcomposite resin.(b) Change inappearance of bilateralcentral incisors withgemination/fusion.

a

b

Figures 5a and 5b.(a) Smile view of toothNo. 8 with gemination.(b) Retracted view ofteeth Nos. 8 and 9.

a

b

Figure 6. Panoramic radiograph demonstrates no missingpermanent teeth.

tooth No. 8 to the distal of tooth No. 9 was recorded. Theamount of reduction of tooth No. 8 was based upon thecombined widths of teeth Nos. 8 and 9. Reducing the mesialwidth of tooth No. 8 would create space to allow restorationof the mesial of tooth No. 9 to equalize the widths of the 2central incisors. To accomplish this, the diamond in thehandpiece was placed to slightly angle the tip of thediamond on the mesial and distal incisal thirds of tooth No.8. This shaped reduction created the space needed so thatafter the restoration of tooth No. 9, the perception would bethat the incisal width of tooth No. 8 was the same width astooth No. 9. The enamel surfaces where the mesial anddistal width reductions were accomplished were thensmoothed with a needle-shaped, 10-bladed, compositeresin finishing bur (SE8-10 [SS White Burs]).

The facial surface of tooth No. 9 was lightly prepared androughened. The procedure to change the appearance of thenotched incisal edge and facial invagination included etchingthe prepared enamel for 15 seconds with a 37% phosphoricacid etchant and rinsing for 10 seconds with an air-waterspray, then drying the tooth. A fifth-generation adhesive(Excite [Ivoclar Vivadent]) was applied to the teeth with adisposable brush (BendaBrush), and air was applied overthe adhesive to thin and evaporate the solvent in theadhesive. The adhesive was light-cured for 10 seconds witha high intensity LED curing light (bluephase 20i [IvoclarVivadent]). A nanohybrid composite resin (IPS EmpressDirect) was placed and shaped on the facial surface of toothNo. 8, then light-cured for 10 seconds. The composite resinwas shaped with disks (X-T Soflex [3M ESPE]) and polishedwith composite polishing abrasives (Astopol [IvoclarVivadent]) (Figure 9).

After shaping and restoring tooth No. 8, the mesiolingualand mesiofacial surfaces of tooth No. 9 were slightlyroughened with a medium grit diamond, and a dead soft metalmatrix was wrapped around tooth No. 8. Following the sameadhesive procedure, the nanohybrid composite resin wasplaced on themesial surface of tooth No.9 and shaped to haveproximal contact with tooth No. 8. Using disks, the restorationwas shaped and finished and polished as previouslydescribed. In cases with the presence of a unilateral double

tooth, the appearance of the width of the tooth at the gingivalmargin many times cannot be changed. For this patient with ahigh smile line, the difference in width was still apparent. Eventhough the width and shape of tooth No. 8 at the gingival linewere different from tooth No.9 due to anatomic considerations,the change in the width of teeth Nos. 8 and 9 at the incisal thirdprovided a reasonable compromise for this difficult-to-manageclinical situation (Figures 10a and 10b).


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Figure 7.Measurement of teethNos. 8 and 9 helps inplanning the final widthof both maxillary centralincisors afterrestoration.

Figure 9.Tooth No. 8 restoredwith a direct bondednanohybrid compositeresin.

Figures 8a and 8b.(a) Shaping the mesialsurface of tooth No. 8with a medium gritdiamond.(b) Shaping the distalsurface of tooth No. 8with a medium gritdiamond.

a

b

CONCLUSIONWhile teeth with gemination and fusion are uncommon, whenthey are encountered, the clinician must present the patientwith all treatment options.Cases of primarily aesthetic concerncan be conservatively treated with high patient satisfaction.Double teeth morphology that places the pulp and periodontaltissues at risk, as well as causing orthodontic concerns, canhave treatment plans with aggressive management. Thepatient will benefit from a treatment plan based on thereduction of risk factors that can lead to pathology,improvement of tooth function, and satisfaction of both thepatient’s and clinician’s aesthetic concerns.

REFERENCES1. American Academy of Pediatric Dentistry Council on

Clinical Affairs. Guideline on oral health care/dentalmanagement of heritable dental development anomalies.Pediatr Dent. 2008-2009;30(suppl 7):196-201.

2. Ng FK, Messer LB. Dental management of amelogenesisimperfecta patients: a primer on genotype-phenotypecorrelations. Pediatr Dent. 2009;31:20-30.

3. Bai H, Agula H, Wu Q, et al. A novel DSPP mutationcauses dentinogenesis imperfecta type II in a largeMongolian family. BMC Med Genet. 2010;11:23.

4. Ten Cate AR.Oral Histology: Development, Structure,and Function. St. Louis, MO: Mosby; 1998:81-102.

5. Türkaslan S, Gökçe HS, Dalkiz M. Esthetic rehabilitationof bilateral geminated teeth: a case report. Eur J Dent.2007;1:188-191.

6. Aguiló L, Gandia JL, Cibrian R, et al. Primary doubleteeth. A retrospective clinical study of their morphologicalcharacteristics and associated anomalies. Int J PaediatrDent. 1999;9:175-183.

7. DuncanWK, Helpin ML. Bilateral fusion and gemination:a literature analysis and case report.Oral Surg Oral MedOral Pathol. 1987;64:82-87.

8. Levitas TC. Gemination, fusion, twinning andconcrescence. ASDC J Dent Child. 1965;32:93-100.

9. Hernandez-Guisado JM, Torres-Lagares D, Infante-Cossio P, et al. Dental gemination: report of a case.Med Oral. 2002;7:231-236.

10. Budd CS, Reid DE, Kulild JC, et al. Endodontic treatmentof an unusual case of fusion. J Endod. 1992;18:133-137.

11. ClemWH, Natkin E.Treatment of the fused tooth: report ofa case. Oral Surg Oral Med Oral Pathol. 1966;21:365-370.

12. Neves AA, Neves ML, Farinhas JA. Bilateral connationof permanent mandibular incisors: a case report. Int JPaediatr Dent. 2002;12:61-65.

13. Schuurs AH, van Loveren C. Double teeth: review of theliterature. ASDC J Dent Child. 2000;67:313-325.

14. Yuen SW, Chan JC,Wei SH.Double primary teeth and theirrelationship with the permanent successors: a radiographicstudy of 376 cases.Pediatr Dent.1987;1:42-48.

15. Buenviaje TM, Rapp R. Dental anomalies in children: aclinical and radiographic survey. ASDC J Dent Child.1984;51:42-46.

16. Ballal NV, Kundabala M, Acharya S. Estheticmanagement of fused carious teeth: a case report.J Esthet Restor Dent. 2006;18:13-18.

17. Santos LM, Forte FD, Rocha MJ. Pulp therapy in amaxillary fused primary central incisor—report of a case.Int J Paediatr Dent. 2003;13:274-278.

18. Karaçay S, Gurton U, Olmez H, et al. Multidisciplinarytreatment of “twinned” permanent teeth: two casereports. J Dent Child (Chic). 2004;71:80-86.

19. Järvinen S, Lehtinen L, Milén A. Epidemiologic study ofjoined primary teeth in Finnish children.Community DentOral Epidemiol. 1980;8:201-202.

20. Blank BS, Ogg RR, Levy AR. A fused central incisor.Periodontal considerations in comprehensive treatment.J Periodontol. 1985;56:21-24.


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Figures 10a and 10b.(a) Completed restora-tion of teeth Nos. 8 and9 (retracted view).(b) Smile view of teethNos. 8 and 9.

a

b

21. O’Reilly PM. Structural and radiographic evaluation offour cases of tooth fusion. Aust Dent J. 1990;35:226-229.

22. Hülsmann M, Bahr R, Grohmann U. Hemisection andvital treatment of a fused tooth—literature review andcase report. Endod Dent Traumatol. 1997;13:253-258.

23. Tuna EB, Yildirim M, Seymen F, et al. Fused teeth: areview of the treatment options. J Dent Child (Chic).2009;76:109-116.

24. Weiss JK. The double tooth. J Clin Orthod.1980;14:780-787.

25. Melnik AK. Orthodontic movement of supplementalmaxillary incisor through the midpalatal suture area.Am J Orthod Dentofacial Orthop. 1993;104:85-90.

26. Itkin AB, Barr GS. Comprehensive management of thedouble tooth: report of case. J Am Dent Assoc.1975;90:1269-1272.

27. Paskow H. Self-alignment following interproximalstripping. Am J Orthod. 1970;58:240-249.

28. Ozalp SO, Tuncer BB, Tulunoglu O, et al. Endodontic andorthodontic treatment of fused maxillary central incisors:a case report. Dent Traumatol. 2008;24:e34-e37.

29. Velasco LF, de Araujo FB, Ferreira ES, et al. Esthetic andfunctional treatment of a fused permanent tooth: a casereport.Quintessence Int. 1997;28:677-680.

30. Braun A, Appel T, Frentzen M. Endodontic and surgicaltreatment of a geminated maxillary incisor. Int Endod J.2003;36:380-386.


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POST EXAMINATION INFORMATION

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POST EXAMINATION QUESTIONS

1. Tooth anomalies due to developmental disorders ofteeth can be responsible for variations in size, shape,and number of teeth, as well as missing teeth andvariations in tooth structure due to enamel or dentinmalformation. These defects can be caused by:a. Local factors.b. Systemic factors.c. Hereditary factors.d. All the above.

2. Disturbances to the tooth bud during developmentsuch as trauma to the primary anterior teeth can lead tocolor defects or malformations of the enamel surface.The tooth bud is made up of cells derived from:a. Flowering odontoblastic and osteoblastic processes

of the pulp.b. The ectoderm of the first brachial arch and the

ectomesenchyme of the neural crest.c. The bark of the endosperm.d. Mitosis phase of the epithelium of the alveolus.

3. The terms double teeth, joined teeth, fused teeth, ortwinning can describe what malformation(s) that canalter the appearance of teeth?a. Gemination.b. Fusion.c. Concrescence.d. All the above.

4. Gemination appears as:a. Four tooth buds fused from the cemento-enamel

junction (CEJ).b. Two crowns sharing the same root with a

characteristic shallow groove along the facial surface.c. A double rooted incisor with 2 individual root canals

joined together in the middle but with 2 separatecrowns not fused together.

d. Two teeth joined together with each crown rotated180º mesial to each other and the presence of acommon CEJ.

5. Fusion of teeth is:a. Double tooth that may involve the entire length of the

tooth or the roots only.b. Three teeth joined from the apex of the root up to the

cementoenamel junction.c. Two separate crowns of maxillary incisors with the

teeth joined at the CEJ.d. One maxillary incisor joined to a supernumerary tooth

at the apex with a facial position and mesial tipping.

6. In the case of both gemination and fusion, theappearance is usually that of:a. Two distinctly different crowns on a common root.b. Three distinctly different crowns (one a

supernumerary tooth) on a common root.c. One unusually wider than normal tooth.d. Two separate teeth that are joined at the cementum.

7. Syndromes associated with double teeth include allthe following EXCEPT:a. Achondroplasia.b. Focal dermal hypoplasia.c. Gout.d. Chondroectodermal dysplasia.


9


8. The clinical appearance of gemination is either 2completely or incompletely separated crowns with asingle root and root canal. It has been reported thatcomplete separation of the crowns can occur (2 teethfrom one tooth bud).a. Both statements are true.b. The first statement is true, the second statement is

false.c. Both statements are false.d. The first statement is false, the second statement is

true.

9. Patients with tooth fusion often have fewer than the fullcomplement of teeth within the arch if the fused toothis counted as a single tooth. It is not unusual for afused tooth to have 2 separate root canals.a. Both statements are true.b. The first statement is true, the second statement is


true.

10. In both clinical cases presented, the unusually widerthan normal maxillary incisor required that the toothwidth be taken into account when achieving anaesthetic result. In both cases, the tooth (teeth) was(were) ____________________ to make the twinned(double toothed) incisor look more normal.a. Reduced in width with diamonds using a high-speed

handpiece.b. Made wider with porcelain veneers.c. Made wider with porcelain-metal crowns.d. Increased in width and length with porcelain veneers.

11. Gemination affects:a. Primary teeth only.b. Permanent teeth only.c. Primary and permanent teeth.d. Supernumerary mandibular molars only.

12. Disfigurement in the appearance of geminated teethdue to irregularities to the enamel are seen as:a. Talon cusps.b. Bimodal incisal edges.c. Deep invaginations on the facial and lingual

surfaces.d. Deep lingual pits on maxillary lateral incisors.

13. Patients with geminated teeth have a normal numberof teeth in the quadrant where the tooth is present. Itis not unusual for a geminated tooth to have deepinvaginations on the facial and lingual surfaces.a. Both statements are true.b. The first statement is true, the second statement is


true.

14.When restoring double teeth, other clinicalconsiderations can include:a. Endodontic treatment.b. Periodontal treatment.c. Orthodontic treatment.d. All the above.

15. One treatment modality for fused teeth is separatingthe teeth. Hemisection of fused teeth can beperformed without endodontic treatment if the fusedteeth have separate roots and no communicationbetween the dental pulp of each tooth.a. Both statements are true.b. The first statement is true, the second statement is


true.

16. As stated in the article, definitive diagnosis fordouble teeth can be difficult to make. Criteria todifferentiate germination and fusion include all thefollowing EXCEPT:a. Morphology of the double teeth.b. Mandibular posterior compared to maxillary posterior

molars.c. Number of teeth.d. Crowding.


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