Management of subgingivally fractured maxillary anterior tooth: a multidisciplinary approach

Abstract

The major challenge in traumatic injuries is the management of subgingival fracture of anterior teeth. Forced orthodontic extrusion is a suitable approach for these teeth as it provides both a sound tissue margin for final restoration and creates a periodontal environment (biological width) which is easy for the patient to maintain. Restoration after orthodontic eruption may present a more conservative treatment choice in young patients compared with the prosthetic restoration after extraction. This paper reports a case of the fractured maxillary anterior tooth at the subgingival level that was managed by forced orthodontic extrusion after endodontic therapy followed by aesthetic rehabilitation, a much-forgotten technique not utilised routinely yet conservative and cost-effective.

Background

Management of subgingival fracture in the aesthetic zone provides the greatest challenge to the clinician. The biggest challenges associated with these fractures, are the loss of ferrule and compromised biological width.^{1 2}

Orthodontic eruption and periodontal crown lengthening (PCL) are the two option available, which clinically expose the fractured cervical margins and provides adequate tooth structure for ideal prosthodontic rehabilitation.

PCL exposes adequate part of the root by removing the crestal portion of the alveolar bone. However, orthodontic intercession helps in the forceful extrusion of the tooth at the same time restoring the biological width, maintaining the level of the alveolar bone and providing aesthetics.^{3 4}

The point of reporting this paper is to outline a detailed multidisciplinary treatment option of a traumatised anterior tooth with subgingival fracture and how this approach can help in preserving the periodontal tissue and at the same time the alveolar bone.

Case presentation

A 17-year-old male patient reported to the department of conservative dentistry and endodontics with his fractured front tooth due to fall, a day before. Clinical examination revealed a fracture of the upper left central incisor near the coronal area, at multiple sites (tooth 21) with exposure of the pulpal tissue and mobility of coronal fragment (figure 1a and b). The fractured segments were removed, which revealed that clinically the fracture line extended subgingival involving the palatal side. Further, it was observed that around 1 mm of tooth surface on the buccal side was uncompromised without any mobility.

Figure 1.

(A) Preoperative occlusal view. (B) Preoperative labial view. (C) Preoperative intraoral periapical radiograph.

INVESTIGATIONS

Radiographic examination revealed a completely mature apex without the presence of any periapical lesion or any additional fracture involving the root (figure 1c).

TREATMENT

Owing to the presence of multiple fragments of the crown of the fractured tooth, the option of reattachment was ruled out. Patient consent was obtained prior to treatment planning after which he was given treatment options of extraction or multidisciplinary approach. He was made aware of the cost, number of visits and prognosis of the treatment plan following which he opted for a multidisciplinary approach. A tentative treatment plan was formulated which consisted of a stepwise treatment including plaque control, endodontic treatment, orthodontic extrusion, prefabricated glass-fibre post followed by a core build-up and finally replacement with a porcelain fused to metal (PFM) crown.

Root canal therapy of the involved tooth was completed immediately on the first appointment. The conservative access opening was prepared to extirpate the pulp and working length was determined. Cleaning, shaping and obturation were done. Postspace preparation was created with pesso reamer. Following which a ‘J’ hook was fabricated with 19-G stainless steel wire for carrying out orthodontic extrusion. It was partially inserted in canal and bonded with light cure composite resin in the prepared postspace following which The removable appliance was fabricated. The orthodontic traction was carried using the ‘J’ hook supported by elastic modules (figure 2a). The patient was asked to wear the appliance daily and was activated every 15 days. Also, the elastic module was replaced every fortnight. The patient was encouraged to maintain good oral hygiene. Subsequently, there was an evident extrusion of about 2 mm after 14 weeks (figure 2b and c).

Figure 2.

(A) Orthodontic extrusion. (B) Postorthodontic extrusion labial view. (C) Postextrusion intraoral periapical radiograph.

The ‘J’ hook was detached and gutta percha material was removed from root canal using Gates Glidden drills. Postspace preparation was created using pesso reamers. A prefabricated glass-fibre post (figure 3A) was cemented with resin cement. The composite resin core (Z 350, 3M ESPE) was placed and tooth preparation was undertaken for crown placement (figure 3B). Further, an impression was taken and PFM crown was prepared and cemented (figure 3C and D).

Figure 3.

(A) Fibre-post placement. (B) Crown preparation. (C) Prosthesis placement. (D) Postoperative intraoral pericapical radiograph.

Outcome and follow-up

The patient was reviewed after 1 and 6 months respectively, for treatment outcome and was found to be stable and well adapted.

DISCUSSION

According to Ingber, an adequate distance of 3 mm is a must between restorative margin and alveolar crest in order to facilitate complete healing and restoration of the tooth. Placement of restorative margins within a biological width is an important consideration, as violation of which may lead to complications such as gingival inflammation, loss of clinical attachment and bone loss. Hence, it becomes utmost necessary to preserve a healthy periodontal structure during restoration in subgingival areas.⁵

Various treatment options have been indicated for subgingivally fractured anterior teeth in young adults:

1. Natural tooth crown reattachment as a temporary or permanent restoration.⁶

2. Adhesive restorations or prosthetic crown restoration after an orthodontic or surgical extrusion.^{7 8}

3. Extraction⁶ followed by an implant or fixed partial denture.⁹

   The favourable outcome of these kinds of cases is a multidisplinary approach of orthodontic, endodontic, periodontal and prosthetic rehabilitation with patient cooperation.

The treatment approach must aim at the exposure of the subgingival fractured margins without compromising the biological width.

In the present case, forced orthodontic extrusion was used instead of surgical extrusion. Forced orthodontic extrusion can be defined as a movement of vertical translation in a coronal direction obtained through the application of continuous light forces. In orthodontic extrusion, the entire attachment apparatus can be shifted coronally in unison with the tooth.¹⁰

It has been demonstrated by Stren and Becker that orthodontic extrusion is a better aesthetic alternative to surgical crown lengthening. Unlike other orthodontic procedures, in extrusion, bone resorption does not occur and there is additional bone deposition lining the socket.¹¹

In the present case, dental tissue was inadequate for bonding bracket, therefore, traction was applied from the attachment inserted into the canal of the involved tooth after endodontic therapy. The removable appliance was used in the present case due to the advantages pertaining to its fabrication, patient compliance, bite opening and simultaneous extrusion. A similar technique was carried out in other papers published.^{12 13}

Secondary to extrusion using orthodontic technique, post and core were prepared to support the retention of restoration, due to the presence of insufficient dentine. A glass-fibre reinforced composite root canal post along with a composite core was utilised. The bonding of a fibre post to the tooth structure should improve the prognosis of the restored tooth by increasing post retention and reinforcing the tooth structure, especially in the lack of coronal tooth structure. Moreover, satisfactory aesthetic appearance with no risk of gingival discoloration is an important advantage of glass fibre posts.¹⁴

Learning points.

• The multidisciplinary treatment used in the present study requires time, commitment and motivation both from the patient and the dentist.

• However, it is less destructive for tissue than the other treatment options available and is more natural to a patient than a denture.

• It can be a useful tool in the armamentarium of a general dentist.

• Also, it is definitely cost-effective for the patient and at the same time preserves the integrity of the tooth and the tissue, simultaneously.