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References

Burch J, Ngan P, Hackman A Diagnosis and treatment planning for unerupted premolars. Pediatr Dent. 1994; 16::89-95
Di Salvo NA Evaluation of unerupted teeth: orthodontic viewpoint. J Am Dent Assoc. 1971; 82::829-835
Grover PS, Lorton L The incidence of unerupted permanent teeth and related clinical cases. Oral Surg Oral Med Oral Pathol. 1985; 59::420-425
Frank CA Treatment options for impacted teeth. J Am Dent Assoc. 2000; 131::623-632
Alling CC III, Catone GA Management of impacted teeth. J Oral Maxillofac Surg. 1993; 51::3-6
Coombs MI, Moore SR Root resorption caused impacted permanent teeth. Case report. Aust Dent J. 1989; 34::205-208
Howard RD The displaced maxillary canine: positional variations associated with incisor resorption. Dent Pract Dent Rec. 1972; 22::279-287
Knight H Tooth resorption associated with the eruption of maxillary canines. Br J Orthod. 1987; 14::21-31
Roberts-Harry D, Sandy J Orthodontics. Part 10: Impacted teeth. Br Dent J. 2004; 196::319-327
Hall FM, Cook PA Resorption of a first permanent molar. Br Dent J. 1989; 166::19-20
Tabiat-Pour S, Newlyn A Root resorption of a maxillary permanent first molar by an impacted second premolar. Br Dent J. 2007; 202::261-262
Hall FM, Cook PA Resorption of a first permanent molar. Br Dent J. 1989; 166::19-20
Harradine NW, Chan KK Bilateral root-resorption of upper first permanent molars. Prim Dent Care. 1995; 2::23-25
Oliver RG Another aggressive unerupted second premolar. Br J Orthod. 1986; 13::61-62
Waterhouse PJ, Nunn JH Crown and root resorption of a maxillary permanent first molar by an impacted second premolar: a case report. Int J Paediatr Dent. 1995; 5::259-262
Butler T, Collard M, Hunter L Case report: a cautionary tale of impacted palatal premolars and molar root resorption. Dent Update. 2009; 36::552-555
Tracey C, Lee RT Root resorption: the aggressive, unerupted second premolar. Br J Orthod. 1985; 12::97-101
Estrela C, Bueno MR, De Alencar AH Method to evaluate inflammatory root resorption by using cone beam computed tomography. J Endod. 2009; 35::1491-1497
Scarfe WC, Farman AG, Sukovic P Clinical applications of cone-beam computed tomography in dental practice. J Can Dent Ass. 2007; 72::75-80

Case report: the importance of careful planning for orthodontic extractions

From Volume 10, Issue 2, April 2017 | Pages 70-71

Authors

Richard Leck

BDS, MFDS RCPSG

Senior House Officer in Oral and Maxillofacial Surgery, Department of Oral and Maxillofacial Surgery, James Cook University Hospital, Marton Road, Middlesbrough TS3 4BW, UK

Articles by Richard Leck

Ushmita Johar

BDS, MFDS RCSPG, LDS RCS

Trust Registrar in Oral and Maxillofacial Surgery, Department of Oral and Maxillofacial Surgery, James Cook University Hospital, Marton Road, Middlesbrough TS3 4BW, UK

Articles by Ushmita Johar

David Farr

FDS RCS, FRCS

Consultant in Oral and Maxillofacial Surgery, Department of Oral and Maxillofacial Surgery, James Cook University Hospital, Marton Road, Middlesbrough TS3 4BW, UK

Articles by David Farr

Abstract

This case describes the root resorption of a maxillary first molar due to an impacted maxillary second premolar tooth. The impacted second premolar tooth was surgically removed leaving a compromised first molar tooth.

CPD/Clinical Relevance: This case demonstrates the importance of thorough assessment of impacted teeth prior to planned orthodontic extraction. It shows that unerupted maxillary premolar teeth have the potential to damage the permanent molar teeth by resorbing the roots. It is especially important to consider this as a potential complication when extracting teeth for orthodontic purposes.

Article

Premolars are the third most likely tooth to be impacted after third molars and canines.1,2,3 Factors associated with tooth impaction are either local or systemic.4,5

Local factors

  • Arch length discrepancy;
  • Premature loss of primary tooth;
  • Presence of supernumerary tooth;
  • Ectopic positioning of the tooth germ;
  • Local pathology, eg odontome;
  • Thickened overlying osseous or mucosa tissues;
  • Obstacles to eruption, eg ankylosed primary molar;
  • Cleft palate;
  • Biomechanical impediments secondary to childhood;
  • Maxillofacial surgery or dento-alveolar trauma.

    • Systemic factors

  • Cleidocranial dysostosis;
  • Other hereditary or syndromic conditions.

    • This case describes the unusual phenomenon in which an upper right second premolar tooth resorbed the roots of an upper right first molar. There are many published articles describing the potential for impacted permanent canine teeth to resorb maxillary incisor teeth.6,7,8,9,10 Root resorption of a maxillary first molar by a second premolar tooth is, by comparison, relatively rare and few case reports exist.11,12,13,14,15,16 A general consensus exists that, provided the impacted premolar is either partly erupted, or unerupted but palpable, it is not likely to cause root resorption of an adjacent molar tooth.16

    Butler et al16 described a case of maxillary first molar root resorption by a second premolar tooth which was impacted, but distinctly palpable. In their study, the injured molar tooth was extracted and the impacted premolar tooth subsequently erupted spontaneously. Conversely, a study by Tracey and Lee17 highlights the ‘potential aggressiveness’ of unerupted, impalpable second premolars.

    Case history

    A 14-year-old boy was referred to the Oral and Maxillofacial Department for dental surgical extractions prior to fixed orthodontic treatment. He had complained that he had crooked teeth and was medically fit and well. Orthodontic examination had revealed a Class II division I incisal relationship, with an overjet of 12 mm on a mild Class II skeletal base with an average lower face height. He had Class II molars bilaterally and severe crowding in the upper and lower arches.

    Tooth UR5 was unerupted and UL4 was erupted but palatally positioned. LR5 was absent, and LL5 was partly erupted and lingually impacted. A supernumerary tooth was found at the apices of UR1, UR2. UR6 had a clinically sound moderately sized amalgam restoration; UR4 had a defective temporary restoration and was unrestorable. UR2 had mesial caries which was restored by the GDP prior to surgery.

    The orthodontic treatment plan was surgical removal of UR5, UR4, UR$, UL4, LL5 under general anaesthetic. Figure 1 demonstrates the impacted UR5, the erupted and crowded UL4, and the partially erupted LL5.

    Figure 1. Pre-operative OPG.

    Figure 2 shows the impaction of UR5, the defective restoration on UR4 and the maxillary supernumerary is visible close to the apex of teeth UR1, UR2.

    Figure 2. Enhanced pre-operative OPG demonstrating the supernumerary tooth.

    Figure 3 shows a periapical film of the UR6, UR5 and demonstrates impaction of UR5, and potential loss of the periodontal membrane space around the UR6.

    Figure 3. Periapical of UR5, UR6.

    Clinically, UR5 was not palpable buccally or palatally, UR4 had a defective glass ionomer cement restoration and had recurrent caries. The maxillary supernumerary was not palpable either buccally or palatally. UL4 was fully erupted and palatal to the line of the arch. LL5 was lingually placed, with deep bony impaction.

    Following surgical removal of the UR5, an area of root resorption affecting the mesio-buccal and mesio-distal roots and the cemento-enamel junction of tooth UR6 was seen. Tooth UR6 was non-mobile, and the patient was discharged without complications.

    Orthodontic treatment was carried out at a local orthodontic practice and follow-up with maxillofacial surgery was not possible. Fixed orthodontic treatment commenced as planned. At a three month orthodontic review, the surgical sites were found to be fully healed, tooth UR6 remained firm and the patient reported no symptoms.

    Discussion

    When a patient presents with an impacted tooth, the radiographs and clinical assessment are helpful to predict the potential path of its eruption. Predictions about the likelihood of pathological changes affecting both the impacted and adjacent teeth are more problematic. Pathological sequelae associated with an impacted tooth include external root resorption of adjacent teeth, as well as dentigerous cyst and adenomatoid odontogenic tumour formation.4

    Previous authors have stressed the importance of locating the exact position of non-palpable impacted maxillary second premolars, as information about their position and developmental stage can assist in deciding on an appropriate management strategy.11,13,15,17

    Potential management strategies for impacted teeth include:4

  • Observation;
  • Orthodontic intervention, or by extracting neighbouring permanent or deciduous teeth;
  • Relocation via surgical repositioning (auto-transplantation);
  • Orthodontic relocation (exposure and traction);
  • Extraction of the impacted tooth itself.

    • Oliver14 described ‘Leaving crowded upper second premolars to find their way into the mouth’ and emphasized the risk of surgical removal due to the anatomical proximity to the maxillary sinus and to adjacent roots.

    Careful planning prior to orthodontic extraction is essential in order to ensure the long-term success of a treatment plan, and substantial root resorption of a permanent tooth will undoubtedly compromise its prognosis. In cases where root resorption is suspected, it may be prudent to carry out further pre-operative investigations such as vitality testing and 3-D imaging.

    Studies have shown that cone beam computerized tomography (CBCT) is useful in the evaluation of inflammatory root resorption and its diagnostic performance is better than that of periapical radiography.18 The benefit of the imaging must, however, be balanced against the risk of an increased radiation dose; a single CBCT may be equivalent to 4–15 conventional panoramic radiographs19 and, as such, clinicians may be reluctant to make use of this technology in young patients.