Ectopic Third Molar in Mandibular Ramus : Report of Two Cases and Literature Review

C l i n M e d International Library Citation: Apaydin A, Salahattin M (2015) Ectopic Third Molar in Mandibular Ramus: Report of Two Cases and Literature Review. Int J Oral Dent Health 1:007 Received: March 13, 2015: Accepted: April 10, 2015: Published: April 13, 2015 Copyright: © 2015 Apaydin A. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Apaydin and Salahattin. Int J Oral Dent Health 2015, 1:2 ISSN: 2469-5734


Introduction
Impaction of mandibular third molars is a common condition, with a frequency of 20%-30%, and a higher prevalence in women [1,2].In some cases the teeth tend to occupy an abnormal position because of lack of space in the posterior side of mandible.Third molar removal is one of the most common surgical procedures [3].Unerupted third molars are normally found near the usual site of eruption.Sometimes, however, these teeth are found at places distant from their points of origin .Ectopic positions include condyle ramus, coronoid process, sigmoid notch and lower border of angle of the mandible.Ectopic mandibular third molars are not very common and the etiology remains unclear.
Impacted mandibular third molars are categorized according to the anterior-posterior space between the second molar and the mandibular ramus, its superior-inferior position, its medial-lateral in the body of the mandible, and the position of its long axis [36,37].Ectopic mandibular third molars, however, are unusual, with their heterotopic positions reported in the condylar area, in the ascending ramus of the mandible, or in the coronoid process.Due to the rarity of this condition, few cases have been reported, and the etiology, clinical features and optimal management of ectopic mandibular third molar are still unclear.
Owing to the rarity of ectopic third molars in the ramus region, we aimed to present two cases in the present paper and review the related literature over the past 35 years (1979-2014).A conservative intraoral surgical technique for tooth removal is also described.

Case 1
A 38-year-old woman visited our outpatient department in April 2013 complaining of pain and swelling on the left side of her face for two weeks.Radiologic examination revealed her lower left third molar, located on the left ascending ramus (Figure 1).It was sitting with the crown facing the neck of the condyle and the apex facing downward.A computerized tomography (CT) scan exposed the relationship of the ectopic tooth to the anatomic structure.It was positioned upward and outward to the close to the outer cortical bone of the ramus.Small follicular space was also identified enveloping to the crown of the tooth.Under endotracheal general anesthesia, intraoral access was obtained via an incision on the anterior edge of the ramus along to the linea oblique externa.The ramus was exposed and an oscillating saw was used to make cuts in the cortical bone at the estimated site of ectopic tooth; then a 2mm carpid round bur with a straight surgical hand piece was used to make a bony window to expose the tooth.The molar was then elevated, enucleated surrounding soft tissues were sent to pathology, and the wound was closed in a routine fashion.At the one-week follow-up the patient complained of slight paresthesia at her labial mucosa on the left side, but this complication had healed after two weeks (Figure 2).Extra-oral examination revealed a swelling over the right side of face extending from the angle of the mandible to the temporal region.
The skin was of normal color.On palpation there was no tenderness or localized rise in temperature.Intra-oral examination revealed   a discharge distal to second molar.Pus aspiration was obtained by needle.Radiological examination revealed a large radiolucent area in the ramus with dimensions of around 4x8.The third molar was positioned in middle of the ramus (Figure 3-5).The crown segment of tooth was facing the lingual side and the apex was facing the vestibular cortex of the mandibular ramus.
The tooth was impacted and displaced superiorly in the ramus, approximating to the outer and anterior cortex of the ramus.There was a slight expansion of that area.Surgical removal was performed under general anesthesia with access in a routine fashion.The bone was removed around the tooth.The tooth was elevated carefully, the bony window enlarged, the cyst epithelium enucleated and the cyst cavity irrigated with saline.The enucleated tissue was sent to pathology department.The histopathology report confirmed the diagnosis of a dentigerous cyst (Protocol No: 43540832212).There was a slight paresthesia in the postoperative period, being fully recovered in 4 weeks.The patient was checked with one week intervals; swelling and the ear pain disappeared gradually.

Literature Review and Discussion
We searched medline Pubmed (http://www.ncbi.nlm.nih.gov/PubMed) using the following key words "ectopic tooth", "third molar" and "mandibular" including articles from 1979-2014, and almost non English papers were excluded.We found 34 cases (37 ectopic teeth) reported in different locations; we identified them 4 subdivision: mandibular ramus, coronoid process, mandibular condyle and mandibular angle.We found higher prevalence in women including 23 cases.The mean age was 46.3 (range 22 to 80) of 11 men and 23 women.10 of the ectopic mandibular third molars were located in ramus, 18 in condyle, 3 in the angulus, 3 in the coronoid process, 2 in the pterygomandibular space and one on the lower edge of the corpus.20 of them were located right side and the other 17 on the left; 18 of the 37 teeth had been removed via intra-oral access, 14 extra-orally, and 5 had not received any treatment (Table 1).The most frequent symptoms were pain and swelling; other symptoms were trismus, difficulty in mastication, pus discharge, bad taste and temporomandibular joint dysfunctions.Of the ectopic molars, 21 were associated with cysts (mostly described as dentigerous cyst), 3 with abscess and 1 with osteomyelitis.
Management of ectopic mandibular third molar depends of several factors such as signs, symptoms and associated pathology.Pathology in the mandibular ramus and the condyle leads to complications (condylar resorption, fracture and osteolysis) [6,18].
The choice of surgical approach is based on to the preference of the surgeon and the location of the tooth.All authors agree that treatment should be designed carefully with the aim of choosing the more conservative technique (in general, intra-oral access is performed whenever possible to avoid scars and nerve injury) [4][5][6][7]13,15,18,24,25,27,38].The use of an endoscope produces better visualization of the surgical field [30].
Where extra-oral access is required, the submandibular and retromandibular routs are most frequently used [1,7,25,29].The preauricular approach provides better vision of the condyle, but leaves a scar.The literature describes the use of an extra-oral approach when the molar is located in the condylar or subcondylar region [2,[4][5][6][7]24,27,30,33,35].We used the intra-oral approach in our cases and managed to reach the teeth and enucleated the cyst reasonably easily and they healed uneventfully (Figure 2,6).
Complications are rare.The most frequent complication is scarring and damage to nerve structure through extra-oral access.Mandibular fractures can be possible when a greater osteotomy is performed.
In summary, our literature review showed more cases of ectopic third molars located in the condylar region than in the ramus or coronoid.The two new clinical cases we present here were in the ramus.One was associated with a dentigerous cyst.Among etiologic hypotheses, odontogenic cysts appear to be the most relevant cause.In most of the reported cases there were no serious complications.

Conclusion
Ectopic molars in the ascending ramus are very rare.The migration of wisdom teeth should be kept in mind and patients should be controlled regularly when impacted teeth have not been removed.
If the decision is removal of the impacted tooth, the procedure should be chosen according to the individual case of each patient.The potential risks, possible complications and benefits of the procedures should be evaluated very carefully.

Table 1 :
Ectopic third molars in different locations.