Dental Materials: Biodentine, a Calcium Silicate Bioactive

Issues of Concern

Setting Reaction and Interaction with Dentin

Biodentine is a 2-part dental material with specific compositions for its powder and liquid components. The powder's primary component is tricalcium silicate.[2] Calcium carbonate and oxide act as fillers.[2] Zirconium oxide is added to the powder for X-ray visibility, and iron oxide is used for shade.[2] The liquid contains calcium chloride, acting as a setting accelerator and a water-reducing agent.[2] Calcium chloride accelerates the setting time of the material and prevents crack formation, a common issue in cement with high water content. The initial setting time for Biodentine is 9-12 minutes.[2] Saliva and blood contamination can delay setting.[3]

The setting reaction of Biodentine involves a hydration process, during which the powder and liquid components are mixed using an amalgamator. This trituration process results in a creamy paste. The reaction of the powder with the liquid forms a silicate hydrate gel and calcium hydroxide (CH).[1] Calcium hydroxide dissociates into hydroxyl (OH⁻) and calcium ions (Ca²⁺), increasing the pH and Ca²⁺ concentrations.[1] This release of Ca²⁺ contributes to the material's bioactivity and apatite-forming properties and stimulates dental pulp cell differentiation, ultimately promoting dentin bridge formation.[1]

Biodentine stands out for its high levels of Ca²⁺ release compared to other materials, such as calcium hydroxide (CH) cement, mineral trioxide aggregate (MTA), and resin-modified calcium silicate (TheraCal LC).[1] The material's solubility plays a significant role in this substantial Ca²⁺ release.[1] Additionally, the release of OH⁻ leads to an alkaline environment, supporting tissue repair and forming a protective necrotic zone between the pulp tissue and the capping material.[1] This necrotic zone safeguards the pulp cells from the alkaline pH of the material, fostering reparative dentin bridge development.[1]

Moreover, Biodentine releases silicon ions (Si⁴⁺) into adjacent dentin, which can stimulate osteoblast proliferation and play a role in mineralization, collagen synthesis, and tissue cross-linking. The ability of Biodentine to form hydroxyapatite crystals after contact with phosphate-containing body fluids further contributes to sealing the tooth/material interface, minimizing microleakage, and creating an environment conducive to reparative dentin formation.[1]

Biodentine interacts with dentin without prior etching or bonding, primarily relying on crystal growth within dentinal tubules.[1] While various studies report the presence of an "interfacial layer" or "mineral interfacial zone" at the Biodentine/dentine interface, some studies report no chemical changes or tag-like structures at this site.[1] Despite the differences in interpretation, it is evident that Biodentine has the potential to interact with and enhance the adjacent tooth structure, promoting remineralization and contributing to dentin bridge formation.[1] The interaction mechanisms may vary between different studies, and further research is necessary to clarify these processes fully.

Properties

• Fast setting
• Similar microleakage than resin-modified glass ionomer cement
• Good marginal integrity
• Bond strength superior to MTA in furcation perforation repair
• Low porosity
• Insufficient radiopacity
• Biocompatible

Microleakage

Restoration microleakage may lead to postoperative sensitivity and secondary caries, resulting in treatment failure.[2] When Biodentine is used as a liner or base material, the potential for leakage should be carefully considered.[2] Biodentine displays similar leakage patterns as resin-modified glass ionomer cement in open-sandwich restorations.[4]

Biodentine has good marginal integrity because of its ability to form hydroxyapatite crystals, which improves sealing at the material-dentin interface.[4] Calcium silicate-based cement interacts with phosphate ions in saliva, forming apatite deposits, which can also increase sealing potential.[4] The nanostructure and slight material expansion contribute to better adaptation.[4] However, more research is needed to determine why leakage occurs with calcium silicate-based materials.

Bond Strength

Studies investigating Biodentine's bond strength with various adhesives did not reveal significant differences between adhesive groups at the same time intervals. Aggarwal et al reported that Biodentine exhibited superior push-out bond strength compared to ProRoot MTA and MTA Plus in furcal perforation repairs, with the added advantage that blood contamination did not affect its bond strength.[2]

Porosity and Material-Dentine Interface

Biodentine demonstrated lower porosity when used in a continuously moist environment, although it might present challenges in dry conditions. Research indicated that Biodentine adapts well to dentine due to micromechanical adhesion.[2]

Radiopacity

Biodentine's radiopacity is lower than other materials, which could affect its practical use. It uses zirconium oxide as a radiopacifier, known for its biocompatibility. However, this choice may not meet the radiopacity standards set by ISO, and the decision to enhance radiopacity should consider potential effects on biocompatibility.[2]

Biocompatibility

Ensuring the biocompatibility of Biodentine is crucial, especially when it comes into direct contact with periradicular and pulpal cells. Overall, research supports Biodentine's biocompatibility, with favorable results regarding cell adhesion and growth compared to glass ionomer cement. Studies utilizing three-dimensional multicellular spheroid cultures and human dental pulp stem cells confirmed the biocompatible and bioactive characteristics of Biodentine.[2]

Clinical Significance

Clinical Applications of Biodentine

The manufacturer indicates Biodentine for both crown and root restoration. Biodentine is recommended as a temporary enamel and permanent dentin substitute in deep carious lesions, deep cervical or radicular lesions, and vital pulp therapy, including pulp capping and pulpotomy. In the root, it can be used for repairing root and furcation perforations and internal and external resorptions. It is also recommended for apexification and retrograde surgical filling.

Clinical Applications of Biodentine: Direct Pulp Capping

Direct pulp capping with Biodentine has been explored in various clinical scenarios. Direct pulp capping protects exposed pulp and promotes pulp vitality by forming tertiary dentin.[1] The prognosis of direct pulp capping depends on the type of pulp exposure, with traumatic or iatrogenic exposures having better outcomes than carious exposures.[1] Recent bioactive materials, such as Biodentine, have improved the predictability of the procedure following carious exposures.

Studies in animal models have shown favorable results for Biodentine in direct pulp capping, although variations between animal and human responses need further investigation.[1] The variations may result from different metabolic and immunologic reactions in human tissues.[1]

For pulp exposures in carie-free permanent teeth, Biodentine and MTA have shown similar clinical results, with both materials promoting the formation of dentinal bridges and minimal inflammatory pulp responses.[1]

In young permanent teeth with immature roots and carious exposures, Biodentine has demonstrated potential as a suitable capping material, showing high success rates in maintaining pulp vitality.

Even in mature permanent teeth with carious exposures, Biodentine has proven effective in preserving asymptomatic teeth, with dentinal bridge formation and positive outcomes reported in clinical studies.[1]

It's important to note that the choice of direct pulp capping material should consider various factors, including the type, size, and site of the pulp exposure and patient age. Although Biodentine appears promising, more research, especially with larger sample sizes, is needed to establish its clinical relevance and success rates compared to other materials like MTA and CH.

Clinical Applications of Biodentine: Primary Teeth Pulpotomy

Pulpotomy is a procedure to preserve the function and vitality of the radicular pulp by surgically removing the coronal part of an exposed vital pulp. Formocresol has traditionally been used because of its clinical success and ease of use, but concern has been raised regarding mutagenic, toxic, and carcinogenic risks. Biodentine has been suggested as an alternative material to formocresol for pulpotomy procedures. A 2019 randomized clinical trial evaluated the use of Biodentine for pulpotomy in primary molars in children, comparing its clinical and radiographic success rates with formocresol.[5] Formocresol was chosen due to its long-term clinical success despite concerns over adverse reactions. MTA, another alternative, presented challenges in handling and setting time.

The study results show high success rates for Biodentine and formocresol pulpotomy techniques over 12 months, which can be attributed to proper protocol, isolation, aseptic conditions, and material handling.[5] The success rates were consistent with earlier research, emphasizing that Biodentine can be a suitable alternative for formocresol in primary teeth pulpotomy.[5] Furthermore, the simultaneous use of Biodentine as a dressing and restorative material offers a clinical advantage over formocresol, which requires additional restorative material in the pulp chamber.[5]

Clinical Applications of Biodentine: Pulpotomy in Permanent Teeth with Symptoms of Irreversible Pulpitis

Vital pulp therapy (VPT) is a minimally invasive approach for managing teeth with inflamed pulps compared to conventional root canal treatment (RCT). Several factors have contributed to the growing popularity of VPT, including the limitations of root canal treatments despite advancements in technology, the advantages of preserving tooth structure, maintaining possible defensive mechanisms of the remaining pulp, and reducing the risk of tooth fracture.[6] Additionally, VPT has shown comparable success rates to RCT over a 5-year follow-up.[6]

Research into pulp biology and the regenerative potential of inflamed pulp has supported the adoption of VPT in select cases. Histological studies indicate that inflammation is often confined to specific pulp areas near the exposure site, with normal histological architecture found in other pulp parts.[6] Clinical symptoms of irreversible pulpitis do not always align with histological findings, emphasizing the need to revise diagnostic terminology and implement minimally invasive treatments.[6]

VPT can yield a high success rate, particularly when the irritant is removed, and is considered successful in many cases. Removing the unsalvageable inflamed part of the dental pulp through partial or complete pulpotomy rather than simply capping the exposure is essential in patients with clinical signs and symptoms of irreversible pulpitis.[6] This approach has been effective when mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) are employed.

A study on the outcomes of Biodentine full pulpotomy in adult permanent teeth with carious exposure and clinical signs of irreversible pulpitis has been conducted. The study's results highlight this pulpotomy approach's success, especially when patients were selected based on the time needed to achieve hemostasis rather than solely relying on clinical symptoms. A full pulpotomy removes the entire coronal pulp while maintaining the health of the remaining radicular portion, increasing the chances of eliminating infected or irreversibly inflamed tissue. The ability to control bleeding after the amputation of the infected pulp tissue is a marker for the degree of inflammation and the potential for healing the remaining pulp tissue, influencing the choice between partial and complete pulpotomy.[6]

While Biodentine has shown promise in previous clinical trials for pulpotomy, this study explicitly assesses its use in adult patients with symptomatic irreversible pulpitis.

The research suggests that full pulpotomy with Biodentine can successfully treat mature permanent teeth with clinical signs and symptoms of irreversible pulpitis. On the 6-month follow-up, 98.4% of cases showed clinical and radiographic success.[6] Clinical treatment success increased to 100% on the 12-month follow-up.[6] These findings suggest that this minimally invasive approach can be a suitable alternative to conventional root canal treatment.[6]

Clinical Applications of Biodentine: Furcation Perforation Repair

Biodentine is indicated as a material for furcation perforation repair. Furcation perforations are communications between the root canal system and the external dental surface in multirooted teeth. Repairing these perforations is a challenging aspect of dentistry. A study comparing two different dental repair materials, Biodentine and ProRoot MTA (Mineral Trioxide Aggregate), was conducted in dogs' teeth to treat furcation perforations.

The key findings and conclusions from the study are as follows:[7]

1. Radiographic Assessment: Biodentine and MTA showed similar radiographic responses after 4 months. This means that the repair materials used have a similar appearance on radiographs of the treated teeth.
2. Micro-CT Assessment: Biodentine had significantly less extruded material into the periodontal tissues than MTA. This is important because extruded material can hinder periodontal reattachment and tissue repair. The ability of Biodentine to minimize extrusion is seen as an advantage.
3. Histological Assessment: Biodentine and MTA demonstrated good biocompatibility, as there was reduced inflammation in the treated teeth, with only a few scattered inflammatory cells. Inflammation was significantly lower in the Biodentine group compared to the MTA group.
4. Hard Tissue Resorption and Repair: Both materials showed similar hard tissue resorption and repair. Both materials allowed for the formation of new mineralized tissue bridges over the remaining radicular pulp tissue.
5. Cementum Repair: Biodentine showed significantly better cementum repair scores compared to MTA. This suggests that Biodentine may be more effective in promoting cementum formation in the furcation area.

The study suggests that Biodentine is a promising biomaterial for repairing furcation perforations, as it demonstrated good biocompatibility, reduced inflammation, and effective repair outcomes. It also had the advantage of extruding less material into the periodontal tissues, which is considered favorable.[7] However, it's important to note that this study was conducted on dogs, and further research may be needed to extrapolate these findings to clinical applications in humans.