A Case Report on Dentin Post: Contender for Commercially Available Post

Introduction

Root canal-treated tooth restoration is important because it affects the entire prognosis of the teeth [1]. Extraction was previously the preferred treatment for severely decayed teeth; however, the aim of dental therapy has changed to a more conservative approach [2]. When a substantial amount of the clinical structure of the crown has been destroyed due to injury, obtaining a suitable restoration anchorage in the remaining dentin can be difficult. As a result, posts are commonly used in endodontically treated teeth to avoid fracture of the remaining tooth structure and tooth loss [3]. In order to restore the tooth's function and appearance, the post and core's main objective is to adequately replace the lost coronal tooth structure. This will ensure that the crown has appropriate anchoring through retention and resistance [4]. From the 18th century to the present, posts have been constructed from a variety of materials, including metal, wood, and, in recent times, ceramic, glass, and carbon fiber, as well as the newest biological dentin post. Cast metal posts and cores were the most common type of dowel/post and core system, they are still the treatment of choice for many dentists in post-endodontic situations; however, they fail twice as frequently as prefabricated metal posts and can result in irreversible root [5]. The elastic modulus of glass fiber-reinforced (GFR) composites posts is comparable to that of dentin [6]. As a result, masticatory forces are gently transmitted from the restoration to the core build-up and tooth post. Metals, on the contrary, have a significantly higher modulus of elasticity, which promotes stress transmission to the root canal wall [7]. With several post systems available and new posts being released before existing ones are fully assessed in the laboratory and clinical research, identifying which one to employ might be challenging [8-10]. New post systems are constantly being introduced to the market, with a growing focus on aesthetic dentistry [11-16]. The current trend emphasizes achieving a natural appearance and translucency in restorations, ensuring they closely resemble the appearance of a healthy, natural tooth.

It a suitable choice for strengthening the root canal, this is due to its ability to decrease stress on the dentinal walls, as well as its biocompatibility, preservation of internal dentin walls, and adaptability to the canal shape [17]. Biological posts have greater tooth strength and retention than metal or glass fiber pre-manufactured posts [18-23]. The importance of biological dentin posts will be emphasized in the present scenario study, demonstrating how they serve as an intelligent and natural solution for tooth restoration while helping to maintain the health of our smiles [24].

Materials and Methods

Case

A dislodged prosthesis in the top left anterior area of the jaw, which had been there for a year, was the 42-year-old female patient's main concern when she came to the Department of Conservative Dentistry and Endodontics. She had no prior issues until a year ago when her prosthesis became dislodged in the upper left anterior region, but she did not seek treatment as shown in (Figure 1). There was no reported history of fever, swelling, or sinus involvement. The patient has no significant past medical history. She underwent root canal treatment two years ago, followed by the placement of a metal-ceramic prosthesis on the maxillary left canine. Based on the clinical and radiographic evaluation, the preliminary diagnosis, following the AAE guidelines (2021), was a previously root canal-treated tooth in the upper left maxillary canine region (Figure 2).

Before initiating the proposed treatment, informed consent was obtained from the patient in written form. While maintaining a 5 mm apical seal, the post gap was created with Peeso reamers (Mani, Prime Dental Product) . Utilizing GC inlay wax, a direct wax imprint of the post area was made (Figure 3). We chose a recently removed, intact maxillary canine and autoclaved it for 15 minutes at 121°C to disinfect it. Next, employing a diamond disk, the tooth was divided buccolingually along its long axis.  To determine the post's form, thickness, and length, the wax impressions of the setup post area were used as a guide. The separated tooth was further shaped into a dentin post using this imprint. The intraradicular post was shaped and adjusted to fit the master cast. It was then conditioned for 30 seconds with 37% phosphoric acid, cleaned, and dried thoroughly. Following that, an adhesive system (Adper Single Bond 2, 3M ESPE, CA, USA) was used. 37% phosphoric acid was applied to the canal's inner surface for 15 seconds to condition it. The adhesive system  was then applied to the post, and it was left to polymerize. The post's exterior and the canal's inside were both coated with dual-cure resin cement (RelyX Unicem-3M ESPE) using a paste carrier. After inserting the post into the canal and applying steady digital pressure, a radiograph  was taken to assess adaptation. The core buildup was done using packable composite (Spectrum®, Dentsply) (Figure 4). An intraoral periapical radiograph was taken to check the dentin post radiographically (Figure 5). Once the tooth was prepared, an impression was taken using additional silicone, and the same dual-cure resin cement was utilized to fabricate and bond a metal-free ceramic crown.12-month follow-up radiograph shows no signs of tenderness with intact periodontium (Figures 6a and 6b).

Results and Discussion

The upper central incisors are the most commonly affected teeth. Trauma to the coronal portion may hamper the aesthetic and function of the tooth. Several scientific and technical advancements in dentistry have occurred over the last few decades, particularly in the field of restorative materials [25].

For teeth that have undergone endodontic treatment, restorative dentistry is still striving for the optimal coronal reconstructions. It is ideal for the post material to have dentin-like physical characteristics, including compressive strength, modulus of elasticity, thermal expansion, and appearance; it must also bond to the root dentin consistently [26]. Biological dentin posts are used in clinical practice for various restorative situations, such as teeth with significant tooth structure loss, fractures, and teeth that have undergoneroot canals. A variety of post systems, including prefabricated or custom-made posts composed of materials like metal, fiberglass, carbon fiber, or ceramics, can be utilized to restore stability and retention in anterior teeth that are damaged [27].

Yet, no commercialized posts meet all of the mechanical and biological specifications. A biological post is a cost-effective substitute method for the morpho-functional restoration of severely damaged anterior teeth which is obtained by extracting human teeth from another person. Dentin posts, which are made from naturally excised teeth, exhibit resilience that is equal to that of a real tooth, are biocompatible with the surrounding tissues, and offer superior bonding to the dental structure and composite resin at a low cost. Furthermore, forming a single biomechanical system (monoblock), adhesive joining of dental structures, cementing agent, and biological post allows for more effective stress distribution along the root, reducing the fracture rate [28]. Research by [26] shows that dentin posts are more resistant to breakage than glass and carbon fiber posts.

This case report emphasizes the innovative approach of restoring endodontically treated teeth using dentin posts [29]. compared teeth restored with fiber-reinforced composite posts to those treated with intraradicular solid dentinal posts and found that the latter demonstrated superior fracture resistance. The enhanced durability of biological posts is attributed to the physico-mechanical properties of dentin, which closely mimic radicular dentin, ensuring an even distribution of stress. Moreover, biological posts function as shock absorbers, transmitting minimal stress to the root dentinal walls. According to a comparison research, dentin posts distributed stress more effectively than glass fiber or stainless steel posts [30] (Table 1).

Table 1 shows the comparative studies between fiber post and biological dentin post.

Bioposts and post space may be precisely sized with the assistance of innovative technologies like computer-aided design and machining (CADCAM). While biological dentin posts offer promising benefits, they are not without challenges that demand close attention. Ensuring their fabrication techniques yield sufficient mechanical strength while fitting accurately into the root canal without compromising biocompatibility is paramount. Concerns surrounding post-retention, especially in teeth with compromised structures, call for thorough assessment and careful treatment planning to mitigate risks. Moreover, long-term performance and durability necessitate ongoing research and clinical monitoring to validate efficacy and manage potential complications effectively [31].

Table 1. The comparative studies between fiber post and biological dentin post