Multifunctional scaffold for pulp-dentin regeneration

Abstract

This invention relates to the development of a biodegradable scaffold containing growth factor and antibiotic loaded nanoparticulate systems with the aim of enabling the regeneration of the pulp-dentin complex of immature permanent teeth with necrotic pulp damaged due to infection, trauma, or developmental anomalies.

Description

[0001] MULTIFUNCTIONAL SCAFFOLD FOR PULP-DENTIN REGENERATION Technical Field

[0002] This invention relates to the development of a biodegradable scaffold containing growth factor and antibiotic loaded nanoparticulate systems with the aim of enabling the regeneration of the pulp-dentin complex of immature permanent teeth with necrotic pulp damaged due to infection, trauma, or developmental anomalies.

[0003] Prior Art

[0004] Patients of all ages suffer from dental caries affecting the quality of life. Despite the self-healing capacity of the dental pulp complex, threatening conditions such as dental caries, trauma, and fracture can significantly jeopardize tooth vitality, which can lead to inflammation of the pulp and ultimately to pulp necrosis. The dental pulp is a soft connective tissue and consists of cells, nerve fibers, and blood vessels embedded in a gel-like ground substance. The primary function of the pulp is to produce dentin and to maintain the biological and physiological vitality of the dentin. Additionally, it possesses a highly sensitive sensory nervous system that generates unbearable pain when the tooth is exposed to mechanical trauma, chemical irritation, or microbial invasion. The pulp tissue of quite small volume covered with a dentin layer can be nourished from only one end at the root apex and is therefore highly vulnerable to external attacks. When it is infected, it is quite difficult for the immune system to eliminate the infection due to the absence of an organized blood circulation network or blood supply. In this case, the current treatment applied in the clinic is to remove the damaged tissues and to fill the void with inert, synthetic materials that cannot perform the biological function of the lost tissue instead of them.

[0005] In regenerative endodontic treatment, which is a more rational approach, removal of the infected pulp and formation of new tissue in its place are aimed, and this treatment comprises disinfection of the root canal following the removal of the infected pulp, provision of blood supply to the canal system from the apical region, and placement of the barrier material onto a blood clot. Different terms such as regeneration, pulp revascularization, and revitalization can be used to define this radical treatment. Studies in the literature have also shown thatregenerative procedures can reach positive results by providing elimination of symptoms, healing of periapical tissues, thickening of root canal walls, and continuation of root maturation with apical closure. In the last 20 years, regenerative endodontic treatments have been performed as therapeutic procedures especially for immature teeth with pulp necrosis and apical periodontitis.

[0006] The regeneration treatment protocol recommended by the American Association of Endodontists (AAE) is summarized below.

[0007] Regenerative Endodontic Procedure Recommended by the AAE first session:

[0008] - Local anesthesia, rubber-dam isolation, and access cavity preparation

[0009] Copious and careful irrigation with 20 mL NaOCl using an irrigation system that minimizes the possibility of the solution overflowing into the periapical space (Low NaOCl concentrations are recommended (1.5% NaOCl (20 ml / canal, 5 min) and followed by irrigation with saline (20 ml / canal, 5 min), the irrigation needle is placed approximately 1 mm away from the root end to minimize cytotoxicity against stem cells in the apical tissues)

[0010] - Drying of the canal with paper points

[0011] - Placement of calcium hydroxide or low concentration triple antibiotic paste Sealing of the cavity with Cavit, IRM, glass ionomer, or another temporary material

[0012] Second session:

[0013] Response to initial treatment should be assessed and if there are symptoms, additional treatment time should be considered.

[0014] - Local anesthesia and rubber-dam isolation

[0015] Copious and gentle irrigation with 20 ml 17% EDTA

[0016] - Drying of the canal with paper points

[0017] Creation of bleeding into the canal system from the apical using an endodontic canal file (over-instrumentation), (should be induced by rotating a pre-curved K-file 2 mm past the apical foramen with the aim of filling the entire canal with blood up to the cemento-enamel junction).• An alternative to creating a blood clot is the use of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), or autologous fibrin matrix.

[0018] Stopping the bleeding at a level that allows for 3-4 mm of restorative material

[0019] • If necessary, an absorbable matrix such as CollaPlug™, Collacote™, CollaTape™ and white MTA as a sealing material are placed over the blood clot - Flowing a 3-4 mm layer of glass ionomer (e.g. Fuji IX™, GC America, Alsip, IL) gently over the sealing material and light curing for 40 s (MTA has been associated with discoloration).

[0020] • Alternatives to MTA (such as bioceramics or tricalcium silicate cements [e.g., Biodentine*, Septodont, Lancaster, PA, USA]) should be considered in teeth with esthetic concerns.

[0021] • For Anterior and Premolar teeth, use of Collatape / Collaplug and restoring with a 3 mm non-staining restorative material, followed by bonding a filled composite to the beveled enamel margin may be considered.

[0022] • For Molar teeth or teeth with PFM crowns, use of Collatape / Collaplug and restoration with 3 mm MTA, followed by use of resin-modified glass ionomer, composite, or alloy may be considered.

[0023] Follow-up of the treatment and clinical-radiographic examination:

[0024] There should be no pain, soft tissue swelling, or sinus tract (often observed between first and second appointments).

[0025] - Resolution of apical radiolucency (often observed 6-12 months after treatment) Increase in the thickness of root walls (this is generally observed before a significant increase in root length and generally occurs 12-24 months after treatment).

[0026] Increase in root length

[0027] - Positive response to pulp vitality test

[0028] The clinical application of pulp-dentin regeneration is in the form of disinfection of the root canal cavity followed by provision of bleeding into the canal system from the apical region and placement of the barrier material and provision of revascularization. The blood clot formed in the cavity serves as a natural scaffold consisting of a cross-linked fibrin network for the regeneration of dental pulp tissue.In the document W02005034789A2, the effectiveness of hydrogel content containing antibacterial agent and effective also with growth factor is mentioned.

[0029] In the document Diana B. Sequeira, Patricia Diogo, Brenda P. F. A. Gomes, Joao Pega and Joao Miguel Marques Santos, ’’Scaffolds for Dentin-Pulp Complex Regeneration” Medicana, 2023 https: / / www.mdpi.eom / 1648-9144 / 60 / l / 7, the use of hydrogel together with growth factor as a scaffold in dental treatment and its effectiveness are mentioned.

[0030] When studies in the prior art are examined, a need has arisen for the development of a biodegradable scaffold containing growth factor and antibiotic loaded nanoparticulate systems with the aim of enabling the regeneration of the pulp-dentin complex of immature permanent teeth with necrotic pulp damaged due to infection, trauma, or developmental anomalies.

[0031] Objectives and Brief Description of the Invention

[0032] The object of this invention is to develop a biodegradable scaffold containing growth factor and antibiotic loaded nanoparticulate systems with the aim of enabling the regeneration of the pulpdentin complex of immature permanent teeth with necrotic pulp damaged due to infection, trauma, or developmental anomalies.

[0033] Another object of this invention is to form a scaffold mimicking the hierarchical structure of the dentin-pulp complex and is the development of providing a versatile effect by means of nanoparticulate systems containing antibacterial agents and growth factors at the same time.

[0034] Detailed Description of the Invention

[0035] The method for producing scaffold, it comprises;

[0036] preparing nanoparticles containing growth factor,

[0037] preparing nanoparticles containing antibiotic,

[0038] producing the 3 -dimensional support providing scaffold (biodegradable hydrogel) containing the prepared nanoparticles.

[0039] Antibacterial, active ingredients, and growth factors to be used for treatment will be integrated into the scaffold by being entrapped into nanoparticle systems.For this purpose, zein or fibroin nanoparticles will be prepared for the encapsulation of the growth factor. Liquid-liquid dispersion technique will be used for the preparation of the nanoparticles. It will be worked such that the polymergrowth factor ratio is 10: 1 - 20: 1.

[0040] The antibacterial agent will be entrapped into nanoparticle systems prepared with natural origin polymers such as chitosan, zein, alginate. Due to its entrapment, an effective release will be realized at lower doses. It will be worked in the range of 100 mg - 200 mg polymer and an active agent (antibiotic agent) to polymer ratio of 1 :20 - 1 : 100 will be used.

[0041] The hydrogels to be prepared will be prepared in the form of hydrogel / cryogel and this preparation will be synthesized at sub-zero temperatures using monomeric or polymeric precursors. As hydrogel precursors, combinations of chitosan, gelatin, sodium alginate, collagen, zein, which are biodegradable polymers of natural origin, will be used. For the preparation of the hydrogels, polymer in the range of 1% - 10% will be used. Furthermore, ratios such as 1 : 1, 2: 1, 4: 1 can be used for polymer combinations.

[0042] In a preferred embodiment of the subject invention;

[0043] - Polymer solutions forming the scaffold are prepared using suitable solutions.

[0044] - Mixtures are prepared in determined ratios (such as 1:1, 2:1, 4:1) for polymer combinations and are homogenized.

[0045] Growth factor and antibiotic loaded nanoparticles are added to the polymer solution and the mixture is poured into a petri dish and frozen below -20 °C for 24 hours and subsequently thawed at 25 °C for 4 hours (one cycle). The freeze / thaw cycle is repeated a minimum of 4 times.

Claims

CLAIMS1. A production method of a biodegradable scaffold containing growth factor and antibiotic loaded nanoparticulate systems with the aim of enabling the regeneration of the pulp-dentin complex of immature permanent teeth with necrotic pulp damaged due to infection, trauma, or developmental anomalies, characterized in that it comprises;encapsulating nanoparticles containing growth factor and antibiotic using liquidliquid dispersion technique,- preparing hydrogels using the encapsulated nanoparticles and combinations of chitosan, gelatin, sodium alginate, collagen, and zein, which are biodegradable polymers of natural origin.

2. The production method of the multifunctional scaffold according to claim 1, characterized in that the hydrogels are prepared in the form of cryogel and synthesized at temperatures below -20 °C using monomeric or polymeric precursors.

3. The production method of the multifunctional scaffold according to claim 2, characterized in that the hydrogel precursors are formed from biodegradable polymers of natural origin.