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Ectopic third molars in the sigmoid notch: etiology, diagnostic imaging and treatment options

  • Marcel Hanisch1Email author,
  • Leopold F. Fröhlich1 and
  • Johannes Kleinheinz1
Head & Face Medicine201612:36

DOI: 10.1186/s13005-016-0133-x

Received: 4 October 2016

Accepted: 29 November 2016

Published: 6 December 2016

Abstract

Background

The etiology of ectopic third molars located in the sigmoid notch of the mandible is unclear. Only a few cases have been reported. The aim of this article is to discuss the etiology as well as treatment options and diagnostic imaging techniques.

Methods

A PubMed and Medline search of the literature from 1965 to 2015 to ectopic third molars in the mandibular notch was performed. Furthermore, a clinical case provided by the authors is reported.

Results

Among the eight reviewed cases, two male and six female patients were affected that ranged from 25 to 62 years of age (mean 48.4). Pain and swelling in the preauricular region or trismus but also the absence of symptoms was reported. Only in two of the summarized articles an extra-oral access for the removal of the tooth was used. The etiology seems to be individually different, however dentigerous cysts and chronic inflammation seem to play an important role in their appearance. While previous diagnostic reports described two-dimensional diagnostic imaging, currently the three-dimensional imaging is common for preoperative surgical planning with respect to removing ectopic molars.

Conclusions

Ectopic third molars in the mandible are a rare condition. The etiology seems to be individually different. Nowadays, three-dimensional imaging is common for preoperative surgical planning.

Keywords

Dentigerous cyst Ectopic third molar Ectopic tooth Mandibular notch Sigmoid notch

Background

Ectopic molars in the mandible are rare cases and the etiology of this condition is still unclear [1]. Ectopic third molars of the mandible have been described in the condylar region, the coronoid process, the ascending ramus and the sigmoid notch. A review by Wang et al. indicated only 13 reported cases in the literature depicting ectopic molars in the ramus region during a period of 30 years [2]. The surgical excision of third molars is one of the most common outpatient surgeries [3], whereas the removal of ectopic molars seem to be an unusual surgical intervention. Preoperative diagnosis is based on clinical findings and diagnostic X-ray examination [4]. In the present paper, we review the literature of all cases describing ectopic third molars found in the mandibular sigmoid notch region, which have been reported over a period of 50 years from 1965 to 2015. Subsequently, we add to this summary our own experience by presenting a new case with an ectopic third molar in the sigmoid notch.

Methods

A clinical case provided by the authors is reported. Furthermore, a literature search in PubMed and Medline databases was achieved by using the following MeSH terms: “sigmoid notch” OR “mandibular notch” AND “ectopic tooth” OR “third molar”. Inclusion criteria were international cases of ectopic third molars in the sigmoid notch, which have been reported in English or native language from 1965 to 2015.

Results

From 1965 to 2015 only eight cases with ectopic third molars that occurred in the sigmoid notch of the mandible have been reported. In addition to six case reports which were written in English language [510], two cases that were presented in native language by an Italian and a Japanese group [11, 12], respectively, were also included. Clinical and radiological features of these eight cases are summarized in Table 1.
Table 1

Clinical and radiological features of ectopic molars in the sigmoid notch reported from 1965 to 2015

Author

Gender

Age

Symptoms

Surgical access

Radiology

Traiger J. et al. 1965 [5]

female

47

firm, hard swelling of the side of the face

extraoral, general anesthetic

posteroanterior and lateral jaw projection; encircling radiolucency

Giardino et al. 1966 [11] (Article in Italian)

female

62

trismus, sporadic pain praeauricular

none

posteroranterior roentgenogram, lateral oblique radiograph; encircling radiolucency

Nishijima et al. 1976 [12] (Article in Japanese)

female

60

trismus, pain and swelling in preauricular region

extraoral, general anesthetic

posteroranterior roentgenogram, lateral oblique radiograph; encircling radiolucency

Granite EL et al. 1985 [6]

female

60

none

none

panoramic radiograph; area of sclerotic bone

Metha DS et al. 1986 [7]

male

25

slowly growing swelling since 2 years

intraoral, general anesthetic

lateral oblique radiograph; radiolucent lesion

Balan N. 1992 [8]

female

30

pain in preauricular region

not specified

lateral oblique radiograph

Fidink Y et al. 2015 [9]

male

45

none

intraoral, general anesthetic

CT, panoramic radiograph; radiolucent lesion

Adachi M. et al. 2015 [10]

female

58

discomfort in the left buccal mucosa

intraoral, general anesthetic

CT, panoramic radiograph; radiolucent lesion

Gender and age prevalence

Six female patients and two male patients were diagnosed with ectopic molars in the sigmoid notch. The age ranged from 25 to 62, with an average age of 48.4 years.

Clinical symptoms

As clinical symptoms the eight reported cases describes pain [8], swelling [7], trismus [5], discomfort of the mucosa [10] as well as combinations of these symptoms [11, 12] or no symptoms [6, 9]. The clinical features of the eight reported cases are summarized in Table 2.
Table 2

Clinical Symptoms described in eight reported cases

Clinical Symptoms described in the eight reported cases

Symptom

Author

Firm hard swelling with complete trismus

Traiger J. et al. 1965 [5]

Trismus and sporadic pain preauricularly

Giardino et al. 1966 [11] (Article in Italian)

Trismus, pain and swelling in preauricular region

Nishijima et al. 1976 [12] (Article in Japanese)

No symptoms

Granite EL et al. 1985 [6]

Slowly growing swelling for two years

Metha DS et al. 1986 [7]

Pain in the preauricular region

Balan N. 1992 [8]

No symptoms

Fidink Y et al. 2015 [9]

Discomfort in the left buccal mucosa

Adachi M. et al. 2015 [10]

Treatment

Treatment was described in all cases except one [8]. Granite et al. reported periodic radiographic examination [6], Giordano et al. indicated denied treatment by the patient [11] whereas three authors referred their patients to intraoral access and extraction of the ectopic molar under general anesthesia [7, 9, 10]. Only two cases described extra-oral surgical access for the extraction of the ectopic molar [5, 12]. In detail, submandibular access was selected in both reports.

Association with cystic lesions

Cystic lesions were described in four cases [5, 7, 9, 12]. Giordano et al. described encircling radiolucency [11]. Adachi et al. also reported encircling radiolucency which was diagnosed pathologically as granulation tissue [10]. One report referred to an area of sclerotic bone surrounding the tooth [6] whereas Balan did not describe any cystic lesion or other abnormalities which could be detected in the radiologic image [8].

Diagnostic imaging

Diagnostic imaging techniques reports from 1992 to 1965 described lateral oblique radiographs [7, 8, 11, 12], a panoramic radiograph [6], or posteroranterior and lateral jaw projection [5, 11, 12]. Diagnostic imaging by three-dimensional methods, in addition to a two-dimensional panoramic radiograph, was only reported by Fidink et al. and Adachi et al. in 2015 [9, 10].

Case presentation

A 51 year-old male was referred to our Clinic of Cranio-Maxillofacial Surgery by his dentist. The patient described pain in the preauricular region for a few days. The panoramic radiograph revealed lower right third molar being dislocated in the sigmoid notch associated with a radioluscent lesion (Fig. 1). In addition, the panoramic radiograph offered generalized periodontitis and an impacted third molar surrounded with a radioluscent lesion on the left side of the mandible. Unfortunately, no earlier radiographic images of the patient were available for comparing the development of the ectopic molar. Clinical intra- and extraoral inspection disclosed no further inflammation signs like swelling, trismus, fever or redness. Also signs of chronic inflammation like fistula did not appear. Cone beam scans (CT) showed the impacted tooth with cranial-dorsal directed roots and bone apposition in the sigmoid notch (Figs. 2, 3, 4). A radiolucent cystic lesion was extending from the peri-coronary region of the tooth to the dental arch. The mandibular canal was compressed but covered by a small sclerotic bone (Fig. 1). Under endotracheal general anesthesia, an intraoral access was selected by incising the anterior edge of the mandibular ramus. In order to expose the sigmoid notch, a subperiosteal dissection was done lingually. Because the tooth was completely osseously covered, bone was removed and the tooth was separated with a surgical drill. The cystic lesion was enucleated and sent routinely for pathological analysis to the Department of Pathology, University Hospital Muenster. Microscopic analysis of the specimen showed stratified epithelium, fibrous tissue with lymphocytic-, plasma cell- and granulocytic infiltration of neutrophilic type and chronic inflammation (Fig. 5). Furthermore, all second molars and the third molar on the left mandible have also been removed. No complications occurred in the postoperative phase. Antibiotics were not given during the entire therapy. Subsequently, periodontal therapy will be performed by the patient’s dentist.
https://static-content.springer.com/image/art%3A10.1186%2Fs13005-016-0133-x/MediaObjects/13005_2016_133_Fig1_HTML.gif
Fig. 1

Panoramic radiograph showing the ectopic third right molar

https://static-content.springer.com/image/art%3A10.1186%2Fs13005-016-0133-x/MediaObjects/13005_2016_133_Fig2_HTML.gif
Fig. 2

Sagital cone beam scan showing the impacted tooth with cranial-dorsal directed roots and bone apposition in the right sigmoid notch

https://static-content.springer.com/image/art%3A10.1186%2Fs13005-016-0133-x/MediaObjects/13005_2016_133_Fig3_HTML.gif
Fig. 3

Coronal cone beam scan showing the impacted tooth with radiolucent cystic lesion superior the inferior alveolar nerve

https://static-content.springer.com/image/art%3A10.1186%2Fs13005-016-0133-x/MediaObjects/13005_2016_133_Fig4_HTML.gif
Fig. 4

Axial cone beam scan showing the impacted tooth in the right sigmoid notch

https://static-content.springer.com/image/art%3A10.1186%2Fs13005-016-0133-x/MediaObjects/13005_2016_133_Fig5_HTML.gif
Fig. 5

Microscopic image of the stratified epithelium demonstrating fibrous tissue with lymphocytic-, plasma cell- and neutrophilic granulocyte infiltration, as well as chronic inflammation (PAS, magnification: 100)

Discussion

Up to now, only a few reports of ectopic third molars located in the mandible were recorded in the literature. The etiology of this condition is still unclear but several causes were discussed. Capelli described a correlation between the lack of space between second molar and the ramus mandibulae leading to an ectopic position of the impacted third molar [13]. Also a relationship involving the growth of the coronoid process and the ectopic position was suspected whenever the base of the ectopic third molar was embedded in the bony-growth tissue of the coronoid process [14]. Moreover, deviant eruption patterns were also assumed as a primordial deviance of the germ leading to ectopic teeth [15]. These theories may apply to be causative for the individual ectopic molars illustrated in the case reports which were summarized in this review. For the case presented in this article, the theory reported by Thoma in 1958 [16] and several other authors like Stafne [17] seems to apply for the identified ectopic molar. Thoma suspected that the pressure of the cystic fluid was responsible for the migration of the tooth. In our reported patient, a dentigerous cyst surrounds the crown. In the panoramic radiograph a radiolucent area similar to a “path” that extended from the dental arch to the ectopic molar in the sigmoid notch, appeared. Possibly, this “path” represents the route of migration starting at the dental arch and ending at the sigmoid notch. As inflammations are known to be supporting the expansion of cysts, the periodontitis determined in our patient could serve as an additional factor for the expansion of the cyst, leading to migration of the tooth. The same theory was reported by Adachi et al. which describes “granulation tissue with chronic inflammation around the crown” being etiological to the process of retrograde migration and forcing up the tooth into an ectopic position [10].

In symptomatic patients surgical removal, after a careful preoperative planning, is the recommended treatment [18]. In the past, diagnostic X-ray examinations were mainly implemented by two-dimensional diagnostic imaging techniques like panoramic radiograph or lateral jaw projection. Reports about complications during or after the removal of ectopic molars in the sigmoid notch like nerve injury, damage of the mandibular joint, bleeding or infections were not described in the reviewed literature. Ghaeminia et al. illustrated in their study that three-dimensional diagnostic imaging, compared to panoramic radiography, can contribute to optimal risk assessment and, as a consequence, allow better surgical planning [19]. Currently, three-dimensional diagnostic imaging techniques are established and can be beneficial in identifying position of the tooth, associated pathology and identifying the position of neurovascular structures [20]. Thus, preoperatively, the appropriate surgical method can be chosen [2].

Conclusions

Ectopic third molars in the sigmoid notch of the mandible are a rare condition with higher prevalence in women. The etiology seems to be individually different, however dentigerous cysts and chronic inflammation seem to play an important role in their appearance. For planning the surgical entryway, which is mostly selected from intraoral as well as the assessment of operative-risks, three-dimensional diagnostic imaging techniques should be a preoperative standard in diagnostics.

Declarations

Acknowledgements

We acknowledge support by Open Access Publication Fund of University of Muenster.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

Availability of data and materials

The datasets supporting the conclusions of this article are available at the Department of Cranio-Maxillofacial Surgery, University Hospital Münster Germany.

Authors’ contributions

MH conceived the study. LFF and JK helped in the acquisition and interpretation of data. MH, LFF and JK participated in literature review, design and drafting of the manuscript. All authors read and approved the final manuscript.

Competing interests

The authors declare that they have no competing interests.

Consent for publication

Written informed consent was obtained from the patient for publication. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Ethics approval and consent to participate

The ethical approval for this study was obtained from the ethical review committee (Ref. no. 2016-474-f-S), Ethikkommission der Ärztekammer Westfalen-Lippe und der Westfälischen Wilhelms-Universität, Münster, Germany. Written informed consent to participate was obtained from the patient.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
Department of Cranio-Maxillofacial Surgery, University Hospital Münster

References

  1. Iglesias-Martin F, Infante-Cossio P, Torres-Carranza E, Prats-Golczer VE, Garcia-Perla-Garcia A. Ectopic third molar in the mandibular condyle: a review of the literature. Med Oral Patol Oral Cir Bucal. 2012;17(6):1013–7.View ArticleGoogle Scholar
  2. Wang CC, Kok SH, Hou LT, Yang PJ, Lee JJ, Cheng SJ, Kuo RC, Chang HH. Ectopic mandibular third molar in the ramus region: report of a case and literature review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;105(2):155–61.View ArticlePubMedGoogle Scholar
  3. Eklund SA, Pittman JL. Third-molar removal patterns in an insured population. J Am Dent Assoc. 2001;132(4):469–75.View ArticlePubMedGoogle Scholar
  4. Salmerón JI, del Amo A, Plasencia J, Pujol R, Vila CN. Ectopic third molar in condylar region. Int J Oral Maxillofac Surg. 2008;37(4):398–400.View ArticlePubMedGoogle Scholar
  5. Traiger J, Koral K, Catania AJ, Nathan AS. Impacted third molar and dentigerous cyst of the sigmoid notch of the mandible. Report of a case. Oral Surg Oral Med Oral Pathol. 1965;19:459–61.View ArticlePubMedGoogle Scholar
  6. Granite EL, Isaacs M, Kross JF. Asymptomatic impacted mandibular third molar in the subcondylar-sigmoid notch region associated with extensive sclerotic bone. J Oral Med. 1985;40(2):91–2.PubMedGoogle Scholar
  7. Mehta DS, Mehta MJ, Murugesh SB. Impacted mandibular third molar in the sigmoid notch region associated with dentigerous cyst-a case report. J Indian Dent Assoc. 1986;58(12):545–7.PubMedGoogle Scholar
  8. Balan N. Tooth in the sigmoid notch. Oral Surg Oral Med Oral Pathol. 1992;73(6):767.View ArticlePubMedGoogle Scholar
  9. Fındık Y, Baykul T. Ectopic third molar in the mandibular sigmoid notch: Report of a case and literature review. J Clin Exp Dent. 2015;7(1):133–7.Google Scholar
  10. Adachi M, Motohashi M, Nakashima M, Ehara Y, Azuma M, Muramatsu Y. Ectopic Third Molar Tooth at the Mandibular Notch. J Craniofac Surg. 2015;26(5):455–6.View ArticleGoogle Scholar
  11. Giardino C, Valletta G. Heterotopia of the lover 3d molar on the level of the sigmoid notch. Clinical case. Arch Stomatol (Napoli). 1966;7(4):323–7.Google Scholar
  12. Nishijima K, Kishi K, Komai M, Maeda K, Wake K. A case of impacted third molar and dentigerous cyst located below the sigmoid notch of the mandible. Nihon Koku Geka Gakkai Zasshi. 1976;22(3):391–5.PubMedGoogle Scholar
  13. Capelli Jr J. Mandibular growth and third molar impaction in extraction cases. Angle Orthod. 1991;61(3):223–9.PubMedGoogle Scholar
  14. Keros J, Susić M. Heterotopia of the mandibular third molar: a case report. Quintessence Int. 1997;28(11):753–4.PubMedGoogle Scholar
  15. Toranzo Fernandez M, Terrones Meraz MA. Infected cyst in the coronoid process. Oral Surg Oral Med Oral Pathol. 1992;73(6):768.View ArticlePubMedGoogle Scholar
  16. Thoma KH. Oral Surgery. 3rd ed. St. Louis: C.V. Mosby Co; 1958. p. 538.Google Scholar
  17. Stafne EC. Oral Roentgenographic Diagnosis. 4th ed. Philadelphia: W.B. Saunders Co; 1958. p. 51–5.Google Scholar
  18. Procacci P, Albanese M, Sancassani G, Turra M, Morandini B, Bertossi D. Ectopic mandibular third molar: report of two cases by intraoral and extraoral access. Minerva Stomatol. 2011;60(7–8):383–90.PubMedGoogle Scholar
  19. Ghaeminia H, Meijer GJ, Soehardi A, Borstlap WA, Mulder J, Vlijmen OJ, Bergé SJ, Maal TJ. The use of cone beam CT for the removal of wisdom teeth changes the surgical approach compared with panoramic radiography: a pilot study. Int J Oral Maxillofac Surg. 2011;40(8):834–9.View ArticlePubMedGoogle Scholar
  20. Okuyama K, Sakamoto Y, Naruse T, Kawakita A, Yanamoto S, Furukawa K, Umeda M. Intraoral extraction of an ectopic mandibular third molar detected in the subcondylar region without a pathological cause: A case report and literature review. Cranio. 2016;3:1–5.View ArticleGoogle Scholar

Copyright

© The Author(s). 2016

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