Surgical approach of impacted mandibular fourth molars: case report

Surgical approach of impacted mandibular fourth molars: case report

FELIPE AURÉLIO GUERRA 1,2 | NATASHA MAGRO ÉRNICA 1,3 | GERALDO LUIZ GRIZA 1,3 | ELEONOR ALVARO GARBIN JÚNIOR 1,3

ABSTRACT

Supernumerary teeth are more frequent in the permanent dentition of the maxilla, and prevalent in male gender. Their presence may cause delay at adjacent teeth eruption, malocclusion, cystic formation, and root resorption. Since fourth molar presence is rare, early diagnosis is the key to accurate conduct and reduction of injuries at the time of its extraction. That is based on a thorough clinical evaluation and appropriate complementary exams. A twenty-one-year-old male patient, with no relevant medical history, presented for extraction of the third and fourth molars, with absence of pain or sensorial complaints. After clinical exam, radiographic, and computed tomography an analysis, the treatment plan was extraction of all third and fourth molars. Surgical procedure employed was effective in removing the included teeth, with adequate surgical time and no postoperative complications. Early diagnosis along with correct treatment planning through imaging exams such as computed tomography is of great value for success in the management of retained and supernumerary teeth.

Keywords: Impacted tooth. Supernumerary tooth. Oral surgery.

1 Universidade Estadual do Oeste do Paraná, Faculdade de Odontologia, Centro de Ciências Biológicas e da Saúde, Residência em Cirurgia e Traumatologia Bucomaxilofacial (Cascavel/PR, Brazil).

2 Especialista em Cirurgia e Traumatologia Bucomaxilofacial, Universidade Estadual do Oeste do Paraná (Cascavel/PR, Brazil).

3 Doutor(a) em Cirurgia e Traumatologia Bucomaxilofacial, Universidade Estadual Paulista, Faculdade de Odontologia de Araçatuba (Araçatuba/SP, Brazil).

How to cite: Guerra FA, Érnica NM, Griza GL, Garbin Júnior EA. Surgical approach of impacted mandibular fourth molars: case report . J Braz Coll Oral Maxillofac Surg. 2019 Jan-Apr;5(1):41-5. DOI: https://doi.org/10.14436/2358-2782.5.1.041-045.oar

Submitted: October 05, 2017 - Revised and accepted: April 18, 2018

» The authors report no commercial, proprietary or financial interest in the products or companies described in this article.

» Patients displayed in this article previously approved the use of their facial and intraoral photographs.

Contact address: Felipe Aurélio Guerra Av. Vital Brasil, 386, Casa 1, Bairro Areião – CEP: 13.414-044 – Piracicaba/SP E-mail: felipeaurelioguerra@gmail.com

INTRODUCTION

Fourth molars are supernumerary teeth located in the distal region of third molars. 1 Males are the most affected, and the anterior maxillary region presents the highest incidence. Maxillary central incisors and molars are the most frequent supernumerary teeth. 2 These teeth may be present in both dentitions; however, the permanent is the most affected. Regarding the prevalence, 77.4% of individuals have one supernumerary tooth; 18.4% present two supernumerary teeth; 2.3% 3 teeth; and only 1.4% have 4 teeth beyond the regular dentition. 3 The supernumerary molars affect only 0.18% of the population. 4

The molars do not have deciduous predecessors; this is important when discussing the etiology of supernumerary teeth. Thus, one of the most accepted theories is the hyperactivity of the dental lamina, which may give rise to a greater number of teeth while proliferating to form the tooth buds. Within this context, the dichotomy theory, inherited factors and syndromes are also possible hypotheses. 5

The classification of supernumerary molars is based on their shape and location. The first may be rudimentary, when the size and morphology do not resemble permanent or supplementary teeth. Regarding the location, they may be considered as paramolars, when beside the third molar; and distomolars, when located in their distal region. 6

Since fourth molars are seldom reported in the literature, 6 this study presents a case of extraction of third and fourth molars and presents considerations regarding the surgical technique employed.

CASE REPORT

A 23-year-old Caucasoid male patient attended the dental clinic for extraction of third molars. Upon anamnesis he stated he did not have any diseases, allergies or harmful habits. A panoramic radiograph was requested (Fig 1) and revealed the presence of four third molars and two supernumerary molars (fourth molars) in the mandible. Considering the uniqueness of the case, a computed tomography was requested to better visualize the relation of teeth and adjacent structures. The upper sequence of coronal tomographic sections evidenced close contact between the inner alveolar nerve and the supernumerary tooth roots on the third quadrant; this proximity remained until the end of crown of tooth #38. The fourth quadrant, observed in the lower sequence, revealed a similar path (Fig 2).

The preoperative medication comprised 1 g of amoxicillin and 8 mg of dexamethasone. After antisepsis and placement of surgical drapes, the intraoperative period began by anesthetic block of the inferior alveolar nerve by the indirect technique, in which the anterior aspect of the ascending mandibular ramus is palpated in up-down direction, using the index finger. At the point of greatest depression, which consists of the retromolar fossa, the finger is turned so that the nail faces the sagittal plane. The nail center is the insertion point, about 1 cm above the occlusal plane of lower teeth. The needle is always inserted parallel to the occlusal plane of molars, deepening 5 to 6 mm and slowly injecting the anesthetic solution as it is introduced. This blocks the buccal nerve and then the lingual nerve. Afterwards, the needle is withdrawn without removing it from the mucosa, and the anesthetic syringe is directed to the opposite side, at the level of premolars. The needle is inserted until feeling bone contact and retreated a few millimeters, injecting the rest of the anesthetic tube, thus blocking the inferior alveolar nerve. 6

The incision comprised a distal wedge, intrasulcular incision up to the mesiobuccal angle of the second molar and releasing incision. The third molar crown was sectioned in buccolingual and anteroposterior direction, to eliminate the existing impaction. After crown removal, the roots were sectioned. The supernumerary tooth was removed via the alveolus using elevators. Finally, suture was made using 5-0 nylon. The surgical sequence is shown in Figure 3. The same approach was used for both mandibular quadrants. The third upper molars were also extracted in the surgery. Postoperatively, the patient progressed satisfactorily, without complaints of pain or changes in sensitivity. The patient was followed at 7 and 15 days, and the suture was removed in the latter session.

Figure 1: Panoramic radiography.

Figure 2: Computed tomography. Coronal sections of the third and fourth quadrants, evidencing the proximity of the inferior alveolar nerve in relation to the teeth.

A

B

C

D

E

F

Figure 3: A) Incision. B) Crown sectioning of the third molar. C) Aspect after crown removal. D) Sectioning of third molar root. E) Extraction of supernumerary molar. F) Suture.

DISCUSSION

The frequency of supernumerary teeth in the permanent dentition reaches 0.1 to 3.8%, as compared to only 0.3 to 0.8% in the deciduous dentition. The prevalence is observed in the following descending order: mesiodens, upper molars, lower premolars, lower molars and upper premolars. 5

Fourth molars are rarely observed, corresponding to 2% of supernumeraries; 8 in the mandible, they affect only 0.02%. 9 In general, they present smaller size and altered form when compared to the third molars, being the most frequent rudimentary tooth (60.7%). The maxilla is more affected (62.3%) 5 and can reach a ratio of 7:1 when compared to the mandible. 10 Regarding gender, supernumeraries are more observed in males than females, at a ratio of 2.5:1. 5

The etiology of supernumerary teeth is not fully understood. Theories point as possible causes: proliferation of the dental lamina, disorders as Gardner syndromes and cleidocranial dysostosis, division of the tooth bud (dichotomy), inherited factors and history of trauma. 5

The development of complications, such as delayed eruption of adjacent teeth, malocclusion, formation of cysts or root resorptions, are associated with the presence of supernumerary teeth 1 . Special attention should be given to the fourth molars, since their location may worsen cases of pericoronitis and formation of cysts, which are frequent occurrences in third molars. 5

In the present case report, the 26-year-old patient female presented radiographic examination with third and fourth molars on the left side, foci of pain and infection. The left side had a fourth molar, but without any complaints. Surgery for extraction was performed under local anesthesia. The fourth molar on the left side was removed uneventfully; however, the third molar required bone removal and tooth sectioning to reduce the tooth size and minimize the risk of damage to adjacent structures. The tooth on the left side, though without symptomatology, was removed after patient consent. No postoperative complications were reported. 1

The literature shows reports of impacted third and fourth molars sharing the same dental follicle and whose occlusal surfaces were contacting, with the roots in opposite direction – the so-called kissing molars. Computed tomography confirmed the proximity with the inferior alveolar canal and resorption of the lingual bone plate. The patient did not have any symptoms yet agreed with surgical removal of the impacted teeth. 11

The approach to be adopted in supernumerary molars depends on the present symptoms and complications inherent to the tooth permanence. Patients with complaint of pain in the region, affected adjacent teeth, pathological lesions and impactions affecting the permanent dentition should be extracted. The non-surgical approach is reserved for cases without complaints, with normal radiographic examinations and without possible injury to noble structures as the inferior alveolar nerve. The management should consider that the absence of symptoms does not indicate absence of disease, and the term asymptomatic is insufficient for diagnosis. 12

CONCLUDING REMARKS

Agenesis of the third molars is an evolutionary mark, and fourth molars are rarely observed in the mandible Early diagnosis by radiographic examinations and computed tomography, combined with deep technical and anatomical knowledge, is the key to a safe and well-based treatment.

References:

1.

2.

3.

4. Constantino A, Fonseca GM, Cantín M. Bilateral mandibular fourth molars: a case report. Rev Stomatol Chir Maxillofac Chir Orale. 2015 Nov;116(5):312-4. Reddy GS, Reddy GV, Krishma IV, Regonda SK. Nonsyndromic bilateral multiple impacted supernumerary mandibular third molars: a rare and unusual case report. Case Rep Dent. 2013;2013:857147. Bereket C, Çakir-Özkan N, Sener I, Bulut E, Bastan AI. Analyses of 1100 supernumerary teeth in a nonsyndromic Turkish population: a retrospective multicenter study. Niger J Clin Pract. 2015 Nov-Dec;18(6):731-8. Cassetta M, Altieri F, Giansanti M, Di-Giorgio R, Calasso S. Morphological and topographical characteristics of posterior supernumerary molar teeth: an epidemiological study on 25,186 subjects. Med Oral Patol Oral Cir Bucal. 2014 Nov 1;19(6):e545-9. 5.

6.

7.

8.

9. Neville B. Patologia oral e maxilofacial. 4ª ed. Rio de Janeiro: Elsevier; 2016. Clementini M, Ottria L, Pandol C, Agrestini C, Barlattani A. Four impacted fourth molars in a young patient: a case report. Oral Implantol (Rome). 2012 Oct-Dec;5(4):100-3. Marzola C. Anestesiologia. 5a ed. São Paulo: Pancast; 2017. Shahzad KM, Roth LE. Prevalence and management of fourth molars: a retrospective study and literature review. J Oral Maxillofac Surg. 2012 Feb;70(2):272-5. Ohata H, Hayashi K, Iwamoto M, Muramatsu K, Watanabe A, Narita M, et al. Three cases of distomolars. Bull Tokyo Dent Coll. 2013;54(4):259-64. 10. Kara MI, Aktan AM, Ay S, Bereket C, Sener I, Bulbul M, et al. Characteristics of 351 supernumerary molar teeth in Turkish population. Med Oral Patol Oral Cir Bucal. 2012 May;17(3):e395-400. 11. Menditti D, Laino L, Cicciù M, Mezzogiorno A, Perillo L,

Menditti M, et al. Kissing molars: report of three cases and new prospective on aetiopathogenetic theories. Int

J Clin Exp Pathol. 2015;8(12):15708-18. 12. Dodson TB. How many patients have third molars and how many have one or more asymptomatic, disease-free third molars? J Oral Maxillofac Surg. 2012 Sept;70(9 Suppl 1):S4-7.