**Abstract**

Impacted permanent tooth can occur on any tooth in the dental arch. The incidence of retention and impaction of the second molar lies between 0 and 2.3%. It is infrequently found in normal dental patients because most of the second molar impactions are asymptomatic. However, it is a common occurrence in orthodontic practice. The impacted second molar may provoke many pathologic disorders to the adjacent and opposite teeth, eventually malocclusions. There are many treatment modalities in facilitating the eruption of the second molar impaction. Early diagnosis and early treatment are crucial for the successful treatment of mandibular second molar impaction. This article presents an overview of various treatment modalities for an impacted second molar.

**Keywords:** Second molar, Treatment modality, Unerupted tooth, Impacted tooth, Diagnosis, Surgery

#### **1. Introduction**

Unerupted or impacted permanent tooth can involve any tooth in the dental arch. According to many authors, the teeth that are usually involved are the maxillary and mandibular third molars, the maxillary canines, and the mandibular second premolars, respectively. The delayed eruption of second permanent molars is an infrequent occurrence; however, it has clinical impacts when it occurs.

The frequency of occurrence in the impacted second molars is rare and can vary within 0% to 2.3% [1–3]. Permanent molars are exceptionally crucial for the dentition to develop normally and for the facial growth synchronization, along with providing occlusal support for masticatory functions. Any disturbance in the eruption path of permanent molars can lead in a short lower facial height [4].

Most of the time, the pathology from the impacted second molar may provoke many pathologic disorders to the adjacent and opposite teeth. Caries, periodontitis, roots resorption, or pericoronitis may occurred to those neighboring teeth. Other results may form the follicular cyst, tilting of neighboring teeth, and eventually malocclusions [5, 6].

The treatment modalities for unerupted second molars depend on the impaction's severity and the stage of development of the patient [5], which often requires a multidisciplinary approach. The treatment options include surgical procedures [7, 8], orthodontic methods [9, 10], and combined surgical and orthodontic [11]. Some authors suggested extracting the unerupted molar and following orthodontic approaches [10, 12, 13]. Each method has its advantages and disadvantages.

Timely early diagnosis and treatment of permanent second molars' impaction contribute to the most satisfactory consequences with promising and lasting prognosis [14]. Later treatment will be more problematic because not only will the clinical divergence increases with time, but also, the ability to adjust the existing dentition is less.

There are various treatment modalities of the second molar impactions. However, there are no clear guidelines for the clinician to follow when dealt with such cases. Therefore, this review will explain the etiology and incidence of impacted second permanent molars, emphasize the need for earlier diagnosis, and focus on treatment options that can guide the decision-making process.
