# Eruption Treatment of Impacted Teeth Following Surgical Obstruction Removal
## 1 Introduction  
Tooth impaction is characterised by eruption failure once the normal time of eruption has passed and adjacent and antimere teeth have properly erupted [1, 2, 3]. Tooth eruption is a unique biological process characterized by the movement of a tooth from the alveolar process to its functional position in the oral cavity. The accurate eruption mechanism still needs elucidation [4] and depends on the correlation between space in the eruption course, created by the crown follicle, eruption pressure, and the ability of the periodontal ligament to adapt to the eruptive movement. The dental follicle is mandatory and plays a major role in the coordinated alveolar bone resorption and formation. A finely tuned genetic approach of parathyroid hormone 1 receptor (PTH1R) and parathyroid hormone-related peptide (PTHrP) have been shown to be important in bone remodelling during eruption [5]. Impacted permanent teeth are relatively common at the early mixed dentition age [6]. The most commonly impacted maxillary tooth is the canine, occurring in less than 2% of the general population, followed by the central incisor with a frequency of 0.06% to 0.2% [7, 8]. Factors that influence the eruption process of the teeth are local, systemic, and congenital [9]. Some issues have been suggested that result in maxillary central incisor impaction. These could be trauma to primary teeth/dilaceration, a congenitally displaced incisor, ectopic development, cysts, tumours, over-retained or early lost primaryteeth, dense mucoperiosteum, tooth agenesis, syndromes, lack of space, ankylosis, and abnormal morphology [9; 10]. Two of the most common reasons for tooth impaction are supernumerary teeth and odontomas. Supernumerary teeth frequently traced in the mixed dentition period in the maxillary incisors [11; 12; 13; 14] may result in delayed or ectopic eruption of the permanent incisors [15] and extraction should be considered [13]. Odontomas are the most common benign odontogenic tumours (22%) with no gender tendency [16]. They are usually clinically asymptomatic, but often associated with tooth eruption disturbances [17]. The anterior maxilla is an area of high aesthetic demand and, consequently, treatment of unerupted maxillary incisors requires a well-synchronised multidisciplinary approach to obtain an acceptable aesthetic and functional result as soon as possible [10].  
The recommended treatment for both types, i.e., compound and complex odontomas, is complete excision of the tumour, and preservation of the affected teeth [17; 18]. Treatment options following supernumerary extraction or odontoma enucleation, according to the literature, include passive follow-up for spontaneous eruption [11; 12; 13; 14], or the immediate application of an orthodontic force for active traction [19; 20] by means of orthodontic brace cementation on the impacted tooth during the surgical procedure. A third option combines the two [21] and includes follow-up of spontaneous eruption and traction later, if the tooth fails to erupt. The aim of this study is to discuss these three comparative treatment modalities for an impacted incisor following the surgical removal of a supernumerary tooth or an odontoma, and to discuss the conditions and rationale that necessitate their eventual choice and implementation.