Biological post.

Anterior tooth fracture as a result of traumatic injuries, is frequently encountered in endodontic practice. Proper reconstruction of extensively damaged teeth can be achieved through the fragment reattachment procedure known as "biological restoration." This case report refers to the esthetics and functional recovery of extensively damaged maxillary central incisor through the preparation and adhesive cementation of "biological post" in a young patient. Biological post obtained through extracted teeth from another individual-represent a low-cost option and alternative technique for the morphofunctional recovery of extensively damaged anterior teeth.

Anterior tooth fracture is commonly associated with sports, road traffic accident, leisure activity, and caries lesion thus causing functional esthetics and psychosocial problems.[1]

A proper coronary reconstruction that produces satisfactory esthetic and functional conditions for endodontically treated and extensively damaged teeth is still a challenge for dentistry, to achieve these conditions. The making of intra-canal retention is aimed at a better retention and stability of the dental fragments, becomes imperative. This retention can be performed by using posts made from several materials such as fiber, nickel, and chromium. However, no commercially available prefabricated post meets all ideal biological and mechanical requirements.

The use of biological posts made from natural, extracted teeth represents a feasible option for strengthening root canals, thus presenting the potential advantages such as: (1) Does not promote undue stress on dentinal walls, (2) preserves the internal dentin walls of the root canal, (3) presents total biocompatibility and adapts to conduct configuration, favoring greater tooth strength and greater retention of these posts as compared to prefabricated posts, (4) presents resilience comparable to the original tooth, and (5) offers excellent adhesion to the tooth structure and composite resin, (6) at a low cost.[2]

This case report is an earnest effort to recover the function of an extensively damaged maxillary central incisor through the preparation and adhesive cementation of “biological post” in a young patient.[3]

Case Report

A 21-year-old male reported to the Department of Conservative Dentistry and Endodontics, with a complaint of the fractured crown in the right maxillary central incisor. History revealed a loss of tooth structure due to fall, 5 years back. The clinical and radiographic examinations revealed a loss of tooth structure extending to the cervical third, as well as an exposure of the root canal, with necrosis of pulp [Figure 1].

Figure 1

Initial clinical presentation of maxillary anterior fractured tooth and preoperative radiograph

Treatment Plan

Conventional root canal treatment with lateral condensation of gutta-percha, followed by post placement and full crown rehabilitation for replenishing the lost tooth structure.

Post-endodontic Treatment Plan

A post has to be placed to compensate for the amount of tooth been lost. Hence, we decided to use an intraradicular biological post made from cutting the root of extracted and properly sterilized canine and subsequent adaptation of post to the maxillary central incisor.

Consent

The patient received instructions regarding the advantages and disadvantages of biological restoration, as well as information on other treatment options. After agreeing upon the proposed treatment, a consent form was duly signed. In addition, it was made clear to the patient that the post would be obtained from extracted teeth that had been previously sterilized by autoclaving in accordance with standards.

Root Canal Treatment

First, all carious tissue were removed conventional access cavity was prepared, working length determined, cleaning and shaping done, and calcium hydroxide closed dressing given for 2 weeks. Obturation was completed by lateral condensation technique.

The restoration technique initially consisted of the preparation of the root canals for post space and direct molding of prepared space using addition silicon impression material [Figure 2].

Figure 2

(a) Radiographic aspect of endodontic treatment. (b) Post space preparation. (c) Anterior region mold with addition-type silicone

The Making of Dentin Posts

After having established the master cast from the impression, the extracted, donated canines, were autoclaved at 121°C for 15 min. Using a diamond disk, the crown portion was separated from the root, the root was sectioned mesiodistally along the long axis of the tooth. The cementum was removed by abrasion, using diamond drills, and each part of the root was cut in such a way as to form “biological post”[4] [Figure 3].

Figure 3

Post ready after cutting

Adaptation and Cementing of Post to Root Canal

After the intraradicular post had been shaped and suitably adapted to the master cast [Figure 4]; they were then conditioned with 37% phosphoric acid for 30 s [Figure 5], followed by washing, drying, and application of the adhesive system (Adper Single Bond 2, 3M ESPE, CA, USA) [Figure 6].

Figure 4

Post were adapted to the master cast

Figure 5

Application of 37% phosphoric acid in the post

Figure 6

Application of the adhesive system in the post

The inner portion of the canal was conditioned with 37% phosphoric acid for 15 s [Figure 7]. Next, the adhesive system was applied to the post and polymerized [Figure 8].

Figure 7

Application of 37% phosphoric acid in the canal

Figure 8

Application of the adhesive system in the canal

Dual cured resin cement (varolink II, ivoclar) was applied to the inner portion of the canal with the help of a paste carrier [Figure 9] and also to the surface of the post. The post was then inserted into the canal under constant digital pressure [Figure 10]. Core buildup of the tooth structure was done using dual cure core buildup material (fluorocore dentsply) [Figure 11]. Tooth preparation was done, and an impression taken using addition silicone impression material metal free ceramic crown was fabricated and luted using same dual cure resin cement [Figure 12].

Figure 9

Application of the dual cure resin into the canal

Figure 10

Post were then inserted into the canals under constant pressure until the end of the cement polymerization

Figure 11

Core build up, radiograph, crown preparation

Figure 12

Postoperative, postoperative radiograph

Discussion

The use of a dentin post provides biocompatibility, a resilience that is comparable to the original tooth, excellent adhesion to the dental structure and composite resin, at a low cost, as dentin posts are made from donated extracted natural teeth.[5] Furthermore, the formation of a sole biomechanical system (monoblock) adhesive joining of dental structures, the cement agent, and the dentin post allow for a better distribution of stress along the root, minimizing the rate of adhesive and cohesive failure.[6] Steel and titanium posts have higher elastic modulus than dentin, causing a concentration of stress at the tooth restoration interface with an increased risk of tooth fracture when subjected to occlusal loads. When a fiber post, which has lower elastic modulus, is subjected to the same loads, debonding of the post-restoration joint occurs. Lower elastic modulus may raise the risk of spontaneous debonding of the post, instead of vertical fracture of the root.[7]

Concerning the ethical aspect, it is necessary to clarify to the patient and/or his parents or guardian that the post is made from duly donated and properly sterilized extracted teeth, thus preventing biosecurity risks.