PEDIATRIC DENTISTRY/Copyright @1985 byThe American Academy of Pediatric DentistryVolume 7 Number 1 CLINICAL

Delayed eruption of maxillary permanent first and second molars due to anectopically positioned maxillary third molar

M. John Hicks, DDS, MS, PhDRobert O. Greer, Jr. DDS, ScD

Catherine M. Flaitz, DDS, MS

Abstract

This clinical report describes an ectopically positionedmaxillary third molar which prevented eruption of themaxillary permanent first and second molars.

Delayed eruption of permanent teeth in children

and adolescents has been categorized into three sep-arate groups: (1) local factors; (2) systemic conditions;and (3) generalized delayed eruption. 1 Local factorsresponsible for delayed eruption are those which cre-ate a physical barrier to the eruption of the perma-nent tooth. Some of these factors are: (1) presence a supernumerary tooth, (2) an odontoma, (3) odon-togenic and nonodontogenic lesions, (4) retained pri-mary teeth, (5) malformed primary or permanent teeth,(6) trauma to primary predecessors, (7) deficient length, (8) space loss due to caries or premature ex-traction, and (9) bone formation over a permanenttooth following extraction of a primary tooth.26

Several systemic conditions affect eruption of thepermanent teeth. Delayed eruption of the permanentteeth can be expected with conditions such as clei-docranial dysostosis, Down’s syndrome, hypothy-roidism, and hypopituitarism. 7 Generalized delayederuption is observed in a small percentage of the pop-ulation who apparently do not have local or systemicfactors which cause the delay. Eruption in these in-dividuals follows the appropriate sequence, but isconsistently later than the mean eruption times forthe general population.

The prevalence of delayed eruption due to localfactors has been determined for children and adoles-cents. Delayed eruption of one or more permanentteeth occurred in 4.3% of one pediatric population

studied. When delayed eruption due to prematureextraction of primary molars was excluded from thedata, 3.5% of the children still were affected withdelayed eruption due to local factors. The age groupmost affected was the 11-year-old age group (24.4%).No differences were noted between males and fe-males.1 Disregarding impacted third molars, maxil-lary canines have been found to be most affected bydelayed eruption with a prevalence of up to 2.5%s’l°

Mandibular second premolars showed a prevalenceof 0.38%, 9 followed by mandibular canines with aprevalence of 0.01%.9

Clinical Report

A 10-year, 7-month-old Caucasoid male was ex-amined in the pedodontic clinic at the University ofColorado School of Dentistry. The chief complaint ofthe parents and the child was an "improper bite."The health history and physical examination revealeda healthy child with no significant medical or socialhistories and no history of orofacial trauma. Clinicalexamination of the mixed dentition revealed a ClassIII malocclusion with an anterior crossbite, occlusalcaries, and pericoronitis associated with delayederuption of the maxillary right first permanent molar.Only the mesiobuccal and distobuccal cusp tips of themaxillary right first permanent molar were present inthe oral cavity.

A panoramic radiograph was taken in order to de-termine the reason for delayed eruption of the max-illary right first permanent molar. It revealed thepresence of a calcifying third molar positioned ectop-ically and overlaying the second permanent molar inthe maxillary right quadrant (Fig 1). The second mo-lar was inclined more distally than its antimere and

PEDIATRIC DENTISTRY: March 1985/Vol. 7 No. 1 53

FIG 1. Panoramic radiograph reveals the local etiologic fac-tor (arrow) responsible for delayed eruption of the max-illary right first molar. Note position of mandibular thirdmolars relative to mandibular second molars.

and calcified crown of the third molar were submittedfor histopathologic examination. Clinical explorationof the occlusal surface of the first molar proved thetooth to be caries free, indicating that the radiolucentarea present on the radiograph represented an arti-fact.

Microscopic examination of the surgical specimenrevealed several fragments of variably dense connec-tive tissue stroma containing fibroblasts and a fewvascular channels (Fig 3). Numerous aggregations ofcolumnar and cuboidal odontogenic epithelial cellswere associated with the dental follicle (Fig 4). Withinthe connective tissue, odontogenic epithelial rests andstellate cells representing the stratum intermediumwere observed. In addition, several foci of partiallymineralized osseous tissue were present. The histo-pathologic findings were indicative of and consistentwith a hyperplastic dental follicle.

Follow-up examinations revealed eruption of themaxillary right first permanent molar and uneventful

mm.

FIG 2. Appearance of calcified crown of maxillary right thirdmolar following surgical removal.

was positioned superior to the developing third mo-lar. The first permanent molar had less root formationthan its antimere and was blocked physically from itseruption pathway by the presence of alveolar boneoverlaying the ectopically positioned third molar andthe permanent second molar. Radiographic exami-nation of the mandibular arch revealed developingthird molars bilaterally that were positioned superiorto the developing second molars in the ascendingrami. All other permanent teeth were present radio-graphically and appeared to be positioned such thata normal eruption sequence would occur (Fig 1).

The developing maxillary right third molar was re-moved surgically to enhance eruption of the first mo-lar. The alveolar bone overlaying the third molar, alongwith its dental follicle (Fig 2) was removed. An api-cally positioned flap was used to expose partially thecrown of the maxillary first molar. The dental follicle

FIG 3. Dense connective tissue stroma containing fibro-blasts and vascular channels. (H&E stain, 160x)

%^%jg&^?%FIG 4. Columnar odontogenic epithelial cells (arrow) char-acteristic of a benign hyperplastic dental follicle. (H&E stain,160x)

54 DELAYED ERUPTION/ECTOPICALLY POSITIONED MOLAR: Hicks et al.

healing of the soft tissue; the first molar remainedcaries free. Three-month postoperative radiographsrevealed that the first permanent molar had eruptedinto its proper place and that the second molar wasprogressing into a normal eruption pathway (Fig 5).Currently, the patient is undergoing orthodontictherapy.

Discussion

When the pediatric patient with delayed eruptionis encountered, the dentist must consider a numberof etiologic factors. A thorough medical history mayreveal possible systemic conditions related to delayederuption. With systemic etiologic conditions, the pri-mary and permanent dentition should follow a nor-mal eruption sequence, but will be delayed in toothdevelopment patterns and eruption. If systemic con-ditions are ruled out based upon histories, local eti-ologic factors which cause physical barriers to eruptionpathways should be considered.

Both a clinical examination and radiographic sur-vey should be completed. The clinical examinationmay reveal space loss due to premature extraction orinterproximal caries, deficient arch length, mal-formed primary or permanent teeth, or the presenceof a supernumerary or primary tooth retained pastits expected exfoliation time. The radiographic surveyshould include a panoramic radiograph to determineif the etiologic factor is a localized problem. Further

Fie 5. Maxillary first molar (arrow) has erupted into itsproper position and the second molar is progressing intoa normal eruption pathway. Follow-up radiograph takenthree months after surgical removal of maxillary third mo-lar and overlaying alveolar bone.

radiographs may be indicated following examinationof the panoramic film to locate and identify the eti-ologic factor more precisely. The radiographic surveymay reveal the presence of supernumerary teeth, ra-diolucent or radiopaque lesions, trauma to the den-toalveolar process, bone formation over a permanenttooth due to premature extraction of a primary tooth,or soft tissue and osseous lesions that prevent erup-tion.

If a local etiologic factor — including a history ofprevious trauma — cannot be identified, the dentistmust consider referring the patient to an appropriatemedical professional for possible identification of asystemic etiologic condition. If both systemic and lo-cal etiologic factors are discounted, delayed eruptionmay be considered to be a generalized delayed erup-tion peculiar to that individual. In that case, eruptionof the primary and/or permanent teeth should be af-fected by delayed eruption in toto. The eruption se-quence should follow the normal pattern accepted forthe general pediatric population; however, the de-velopment of the teeth will be delayed. The child'sparents or siblings may have a history of delayederuption.

If a local etiologic factor is identified, appropriatetherapy should be instituted to allow eruption of thetooth into its appropriate position. Where partial orincomplete eruption has occurred, the situation mustbe corrected to avoid caries, malocclusion, perico-ronal infections, periodontal and periapical lesions,and bone loss and root resorption involving adjacentteeth. If the tooth is impacted, dentigerous cysts andodontogenic lesions such as fibromas, myxomas, andameloblastomas may develop.5-n'12 The prevalence ofradiolucencies and dentigerous cysts surrounding thecrowns of impacted third molars has been reported.9

An unerupted tooth also may cause malposition androot resorption of adjacent teeth and be a source forneuralgia or referred pain.11-12 If surgical removal ofthe physical barrier is indicated, excised tissue shouldbe submitted for histopathologic examination to en-sure that it is benign and nonrecurring.

In the clinical case reported, pericoronitis was pres-ent in the maxillary right quadrant and associatedwith the exposed mesiobuccal and distobuccal cusptips of the maxillary first permanent molar. The eti-ologic factor for delayed eruption was identifiedradiographically as an ectopically positioned thirdmolar overlaying the developing second molar. Thethird molar and overlaying alveolar bone was re-moved surgically and submitted for histopathologicexamination. Diagnosis of the surgical specimen re-vealed a hyperplastic, benign dental follicle. This pa-tient has been followed and eruption of the firstmaxillary molar has occurred. Continued follow up

PEDIATRIC DENTISTRY: March 1985/Vol. 7 No. 1 55

also will be necessary to ensure that the mandibularsecond molars erupt at the appropriate time due tothe position of the :mandibular third molars.

Dr. Hicks is an assistant professor, dental research unit and growthand development; Dr. Flaitz is an assistant clinical professor andis in the private practice of pediatric dentistry; and Dr. Greer isprofessor and chairman, biological and diagnostic sciences, Schoolof Dentistry, University of Colorado Health Sciences Center, Den-ver, CO 80262. Reprint requests should be sent to Dr. Hicks.

1. Johnsen DC: Prevalence of delayed emergence of permanentteeth as a result of local factors. JADA 94:100-106, 1977.

2. Graber TM: Orthodontics: Principles and Practice, 3rd ed.Philadelphia; WB Saunders Co, 1972 p 331.

3. Posen AL: The effect of premature loss of deciduous molarson premolar eruption. Angle Orthod 35:249-52, 1965.

4. Di Salvo NA: Evaluation of unerupted teeth: orthodonticviewpoint. JADA 82:829-32, 1971.

5. Anneroth G, Modeer T: Odontogenic tumor: a factor in non-eruption. J Dent Child 49:41-43, 1982.

6. Budnick SD: Compound and complex odontomas. Oral Surg42:501-6, 1976.

7. McDonald RE, Avery DR: Dentistry for the Child and Ado-lescent, 2nd ed. St Louis; CV Mosby Co, 1983 p 122.

8. Aitasalo K, Lehtinen R, Oksala E: An orthopantomographicstudy of prevalence of impacted teeth. Int J Oral Surg 1:117-20, 1972.

9. Dachi SF, Howell FV: A survey of 3,874 routine full-mouthradiographs. II. A study of impacted teeth. Oral Surg 14:1165-69, 1961.

10. Thilander B, Jacobsson SO: Local factors in impaction of max-illary canines. Acta Odontol Scand 26:145-68, 1968.

11. Lilly G: Pathologic processes associated with third molars,from a paper read at the Consensus Conference on ThirdMolars, American Association of Oral and Maxillofacial Sur-geons Annual Meeting, Washington, DC, November, 1979;personal communication.

12. Bishara SE, Andreasen G: Third molars: a review. Am J Or-thod 83:131-37, 1983.

Quotable quote: helping hands for nation’s troubled youthTo many adults who look back on their youth with fond memories, it may come as a shock: Young people

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Helping hands for nation’s troubledyouth. U.S. News and World Report

97:50. September 17, 1984.

56 DELAYED ERUPTIONIECTOPICALLY POSITIONED MOLAR: Hicks et al.