# The Presence of Impacted Teeth (Except for Wisdom Teeth) in Orthodontic Patients in Israel
## 1 Introduction  
Impacted tooth refers to a situation in which a tooth will probably not erupt spontaneously into the oral cavity at the estimated time according to dental age, without the aid of surgical intervention and/or orthodontic treatment [1]. The incidence of impacted teeth is 0.8-3.6% of the total population [2], with the most common teeth being, in descending order, wisdom teeth, maxillary amines, mandibular second premolars and maxillary lateral incisions [2]. Among patients with impacted amines, in about 8% of patients, the condition is bilateral [3]. Most studies reported no gender predilection, whereas some studies reported a higher incidence in women compared to men: for example, with impacted amines, a ratio of up to three times greater in women was reported [4; 5]. The causes for impacted teeth are multifactorial and can be divided into three groups: systemic factors, local factors and genetic factors. Endocrine deficiencies and radiation therapy are examples of systemic factors. Local factors include various causes such as problems related to deciduous teeth (over-retained, early extractions), excess number of teeth, dental crowding, and local pathology (such as dentigerous cyst, odontoma, or other pathology), thick mucosa, dental trauma and abnormal position of the tooth. Genetic factors may include amelogenesis imperfeta, alveolar cleft and Cleidocranial dysostosis [3; 4; 5; 6]. Previous studies found a link between genetics and impacted teeth, with higher correlation with other dental anomalies such as peg-shaped/small lateral incisors, infra-occlusion of deciduous molars, small sized maxillary teeth, enamel hypoplasia, and wisdom tooth malformation [7; 8; 9; 10; 11; 12]. There are cases of multiple impacted teeth, which are usually associated with rare genetic syndromes such as Cleidocranial dysplasia, Gardener's syndromeand Noonan's syndrome. However, in rare cases, multiple impacted teeth may be found without any known syndrome [13]. It has been reported that premature birth indicates higher incidence of impacted teeth compared to control group [14]. Clinical features raising suspicion for an impacted tooth may include delay in normal eruption time, crowding with lack of space for eruption, tilted adjacent tooth and over-retained deciduous tooth [8]. The diagnosis is made through clinical examination concomitant with X-ray imaging, to diagnose and assess the location, angulation, and adjacent anatomical landmarks of the tooth [8]. Early diagnosis is crucial for successful treatment [7]. Treatment options should be tailored to the specific patient and may include follow-up, extraction of the deciduous tooth, forced orthodontic eruption (with the help of orthodontic appliances and surgical exposure of the impacted tooth), and extraction of the impacted tooth. Traction of the tooth into the oral cavity is a common treatment option [1; 15]. The two common methods used for surgical exposure of impacted tooth are open exposure (removing the buccal/palatal mucosa and the bone covering the tooth crown leaving the tooth exposed to the oral cavity) and closed exposure (with flap elevation to expose the impacted tooth followed by suturing the flap back to its place after the exposure) [16]. The choice of surgical type depends on several considerations and factors, which include the location of the impacted tooth (buccal or palatal), the depth of the impacted tooth within the bone and the presence of the orthodonticst at the time of surgery [1]. Previous studies comparing the two methods have found no significant difference in terms of postoperative pain, but better periodontal condition in the closed method [17; 18]. The purposes of this study were to determine the presence of impacted teeth (except wisdom teeth) in orthodontic patients in Israel and to examine possible epidemiological link and family genetics to impacted teeth.