Eruption Treatment of Impacted Teeth Following Surgical Obstruction Removal

Abstract

Supernumerary teeth and odontomas are obstacles for spontaneous tooth eruption and may result in impaction. The aim of the study is to present a conservative treatment approach for impacted teeth following surgical obstruction removal by reviewing three treatment modalities: surgery only, which involves the surgical removal of the obstruction and the spontaneous eruption; surgery with immediate traction, which includes surgery combined with immediate active orthodontic brace cementation and traction; and surgery with delayed traction, which combines a surgical procedure of obstacle removal and orthodontic brace cementation with follow-up for the spontaneous eruption. The first two modalities require orthodontic traction either by an additional surgical procedure for orthodontic brace cementation, or combined with the surgical obstacle removal. With the third approach, clinical follow-up is performed via connected ligature wire elongation applied during the surgical procedure for the spontaneous emergence of the impacted tooth. Active orthodontic traction is only employed if the tooth fails to erupt. The visual follow-up via wire elongation serves as a reference during the emergence of the impacted teeth and reduces the need for radiographic examination. The surgical-orthodontic approach saves both further surgery and orthodontics (spontaneous eruption) or further surgery (in failure to erupt).

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 primary teeth, 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.

2. Treatment Methods and Patients

The three treatment modalities are presented in the following cases:

(1)

Surgery only

This conservative approach includes passively waiting for spontaneous impacted tooth eruption following the surgical removal of the obstruction. This is indicated for young patients who have both favourable dental age and tooth position [10], i.e., when the impacted tooth still has the potential to erupt [22]. Figure 1 presents the case of an 8-year-old patient with a supernumerary tooth that blocked the normal eruption of the right permanent central incisor. Extraction of the supernumerary tooth was performed at the age of 7. Because of the central incisor’s position and the stage of maturation, the decision was made to wait for spontaneous eruption with no active orthodontic traction. One year later, when the tooth failed to erupt spontaneously (Figure 1A), an orthodontic treatment was initiated, including space opening and repeated surgical exposure combined with orthodontic brace cementation and active traction.

(2)

Surgery with immediate traction

This method of active orthodontic traction following the removal of an obstruction is usually advised when the root apex is almost or totally closed and the tooth is considered to have poor eruption potential [22,23]. This approach benefits from early impacted tooth eruption, which reduces the psychological impact resulting from a long period of waiting for spontaneous eruption of a missing anterior tooth [24]. Figure 2A presents the case of an 11-year-old patient with a supernumerary tooth that prevented the eruption of the left permanent central incisor. The treatment plan included orthodontic space gaining followed by surgical extraction (Figure 2B) and immediate orthodontic traction of the impacted central incisor (Figure 2C).

(3)

Surgery with delayed traction

This method includes bonding an orthodontic brace (button or eyelet) onto the impacted tooth during the surgical removal of the obstruction, and waiting for spontaneous eruption without applying active orthodontic force [25]. Figure 3 depicts a 7-year-old boy with an impaction of both permanent central maxillary incisors. A panoramic radiograph and a cone beam computer tomography analysis (CBCT) revealed an odontoma lesion, which blocked the left maxillary central incisor area, combined with a large cyst that developed between the right maxillary canine and the central incisor (Figure 3A). The conservative treatment approach included the extraction of the deciduous maxillary incisors and enucleation of the cyst and the odontoma (Figure 3B), followed by cementation of buttons with stainless steel twisted pigtail ligature wires on both central incisors (Figure 3C). The pigtail ligatures were rolled under the gingiva without applying active orthodontic force (Figure 3D).

3. Results

(1)

Surgery only—post repeated surgical exposure combined with orthodontic brace cementation, the patient demonstrated successful orthodontic traction of the impacted central incisors to the correct position in the dental arch after 15 months (Figure 1C) of active orthodontic treatment. As mentioned, two different surgical procedures were required in this case: one for the surgical removal of the supernumerary tooth, and another for the orthodontic brace cementation.

(2)

Surgery with immediate traction—the impacted tooth successfully erupted and aligned in the regained space in the dental arch within 14 months. A single surgical procedure was performed for both the surgical removal of the obstruction, and cementation of the orthodontic brace.

(3)

Surgery with delayed traction—the follow-up for passive spontaneous eruption was conservatively performed every four to six weeks. The length of the connected ligature wires was measured, cut, and re-twisted, which served as a reference for the spontaneous eruption process in consecutive examinations (Figure 3E). After 4 months, the impacted incisors spontaneously emerged into the oral cavity with no need for active orthodontic traction, although this option was preserved throughout the entire follow-up period (Figure 3F).

4. Discussion

Tooth eruption involves bone resorption to form an eruption pathway and interradicular bone formation, root growth, and bone apposition in opposing sides, all regulated by the dental follicle proper. The most common reason for lack of eruption is an abnormality in the dental follicle itself [19]. In this article, we present management options for treating a local physical obstruction associated with tooth impaction. Evidence shows that surgical removal does not necessarily yield spontaneous eruption of the impacted teeth. The rate of spontaneous eruption also depends on the chronological age of the patient [21,26], the developmental stage of the root, the degree of apical displacement, inclination, curvature, and the depth of the impacted tooth, and the preservation of arch space [27]. The overall time for possible complete spontaneous eruption of incisors following the surgical removal of an obstructive object ranges between 7 months and 3 years (with an average of 20 months) [28]. If spontaneous eruption does occur, orthodontic intervention and its possible side effects, such as root resorption, pulp inflammation, gingival recession, inflammatory reaction, and enamel white spot lesions, are avoided [29]. However, approximately 42% of impacted teeth do not erupt spontaneously following the removal of an obstructive object [23]. Moreover, impacted teeth associated with complex odontomas demonstrate a significantly lower rate of post-surgical spontaneous eruption compared to supernumerary tooth removal [23]. Consequently, orthodontic complications such as space closure by adjacent teeth or ectopic eruption of the impacted tooth occurs in 55% of these cases [28,30], requiring additional surgery. Loss of space, as described in the first case presented in this article, dictated the need for a second surgical procedure for orthodontic brace cementation to enable active traction [10,31,32,33,34]. The risk of either a second or even a third unnecessary surgical procedure in the future [23], which may lead to subsequent orthodontic complications of loss of arch space and ectopic eruption [28,30] in cases of spontaneous eruption, may deter some clinicians [20,27]. Hence, they have advocated the application of immediate orthodontic active traction [20]. In the third case presented, the tooth impaction involved a complex odontoma and a severe horizontal inclined position, which may have led to an immediate orthodontic traction. Nevertheless, considering the patient’s clinical aspects, i.e., favourable dental age [26], under-developed roots, and open apices, the clinical decision was to wait for the preferred spontaneous eruption. These treatment alternatives for the impacted incisors due to obstruction are to be known and seriously considered (

Table 1. The three treatment alternatives for obstruction.

	Advantages	Disadvantages
Surgery only	Potentially solved without orthodontics	Second unnecessary surgery Late orthodontics Delay in time till tooth erupts Need for radiographic follow-up
Surgery with immediate traction	Saves second unnecessary surgery Early orthodontics Saves time till tooth erupts	Orthodontics may be prevented
Surgery with delayed traction	Potentially solved without orthodontics Saves second unnecessary surgery Reduces need for radiographic follow-up	Short delay in orthodontics Partially saved time till tooth erupts

) in every patient. As described, the third treatment modality seemed appropriate to enable spontaneous eruption with the benefit of preventing immediate orthodontic force loading, and avoiding additional surgery in case of eruption failure and the need for orthodontic traction. This conservative surgical-orthodontic treatment alternative is highly recommended in young patients due to the expectancy of their normal development potential and prevention of unnecessary orthodontic and additional surgical interventions.

5. Conclusions

In young children with a valid option of spontaneous eruption of an impacted tooth, the suggested treatment following the removal of an obstruction includes a combination of bonding an orthodontic brace and keeping track of spontaneous eruption. This approach is less invasive and avoids both the need for immediate orthodontic traction and for second surgery if spontaneous eruption fails. This article is an attempt to clarify the feasibility of this approach and is intended to assist dental practitioners to reach a logical and information informed approach that is invariably more appropriate for young children. We hope that the discussion outlined in this manuscript and presented in the table above clarifies the pros and cons of the different treatment approaches on this subject, so as to help facilitate the most optimal treatment modality for the different clinical situations of an impacted upper incisor in young patients.