Comparative Evaluation of Calcium Silicate-doped Treated Dentin Matrix and Mineral Trioxide Aggregate as Miniature Pulpotomy Biomaterials in Deep Carious Lesions

1 INTRODUCTION The loss of tooth structure significantly affects the quality of life for patients. This loss occurs due to decay and other non-carious causes. The resulting inadequate aesthetics and impaired function affects even the psychological wellbeing of the patient. Conventional root canal therapy alongside a quality coronal restoration is widely regarded as the standard treatment for this issue. Yet, traditional treatment approaches consistently present challenges such as significant periradicular dentin loss and the risk of reinfection resulting from a compromised coronal seal. Ideally reestablishment of the lost tissue to their pre-disease level should be the goal of these treatment strategies. Regeneration of the dentin-pulp complex and revitalization of the tooth as well as replacement of lost dentin by newly formed dentin should be ultimate objectives of these treatment strategies.

Caries is a biofilm mediated disease of the hard tissues of teeth that is caused by bacterial conversion of fermentable carbohydrates into acids resulting in a acidogenic and cariogenic environment which eventually breaks down the dental hard tissues to form a cavity.

Caries of the permanent teeth was reportedly the most common oral condition as per the Global Burden of Disease Study of 2017. Globally, around 2.4 billion people suffer from caries of the permanent teeth and 486 million children suffer from caries of the primary teeth. The overall prevalence for Dental caries in India is about 54.16%. However there is a remarkable variation in dental caries prevalence rates as per age, diagnostic criteria, dentition, and geographical region.

Involvement of the dentin-pulp complex in the carious process is associated with an inflammatory response. The histopathology and the pathophysiology of the diseased pulp have been extensively studied in the literature clearly illustrating that the parts of the pulpal organ under the inflamed pulpal tissue even in so called "irreversible pulpitis" remain vital or if slightly inflamed are often capable of retaining their vitality especially in the radicular portion. Therefore, there is a growing focus on conserving pulp vitality in different types of teeth with pulp involvement.

Vital pulp therapies are a collection of treatment procedures that aim to conserve the vitality of the pulpal tissue that is affected by the carious process. The procedures include removing the microbial irritation and preventing any new bacterial insult to the pulp by placement of a sealing biocompatible material to protect the pulp from external stimuli. VPT is easier and less invasive than conventional root canal treatment. However the technique is still demanding often requiring magnification and expertise.

Vital pulp therapies have become common in recent years also in part due to the development of highly biocompatible materials like MTA and various formulations of calcium silicate based materials. Calcium hydroxide based pulp therapies have nearly been replaced by MTA; MTA and calcium silicates are now recognized as the benchmark for vital pulp therapies.

A procedure termed 'miniature pulpotomy' has been proposed to improve outcomes of direct pulp capping. By removing the superficial pulp (about 1mm) under a deep carious lesion on a tooth with reversible pulpitis, infected dentin chips and inflamed pulp might be removed to give better access to highly biocompatible materials (MTA and calcium-silicate based materials) as well as provide a clean surgical wound for repair.

The ESE (European Society of Endodontology) and the AAE (American Association of Endodontists) have conflicting guidelines regarding the management of deep and extremely deep carious lesions. The ESE defines Deep caries as 'Caries reaching the inner quarter of dentine, but with a zone of hard or firm dentine between the caries and the pulp, which is radiographically detectable when located on an interproximal or occlusal surface having risk of pulp exposure during operative treatment'.

On the other hand, extremely deep caries is defined as Caries penetrating the entire thickness of the dentine, radiographically detectable when located on an interproximal or occlusal surface. Pulp exposure is unavoidable during operative treatment. The ESE position statement recommends 'Selective caries removal' whereas the AAE recommends complete caries excavation to eliminate the infection in its totality. The Indian Endodontic society (IES) considers VPT as the 'cornerstone of modern endodontics' in management of deep carious lesions and exposed pulps.

By delving into the realm of regenerative dentistry, the exploration of regenerating dental tissues through the art of tissue engineering has stood as a fervent focus of recent research. Structures resembling teeth have successfully been cultured in laboratory environments. Regeneration of dentin has been the most relevant and accessible form of tissue engineering since the dentin forming cells- the odontoblasts stay functional throughout the life of the vital tooth. Tissue engineering (TE) is a branch of regenerative medicine that combines materials science, applied cell biology, and medical engineering to replace or restore organ function. The prevailing technique in tissue engineering involves seeding cells into scaffolds. These are three-dimensional structures that serve as an extracellular matrix, creating a conducive environment for cell growth and development. Ideally, a scaffold should possess the following attributes: an appropriate surface for cell attachment, porosity and permeability to facilitate cell movement and nutrient penetration, and ultimately degrade into harmless and benign compounds. An optimal scaffold may also be shaped to direct cell adhesion, proliferation, migration, and spatial organization since scaffolds provide the blueprint for these processes.

Scaffolds, stem cells, and growth factors form the fundamental components for the regeneration of any tissue. Diverse scaffolds have been researched for dentin regeneration, encompassing synthetically-engineered polymeric and ceramic scaffolds such as synthetic polymers (PLA, PGA, PLGA) as well as naturally derived options like collagen, chitosan, cellulose, alginate, gelatin, among others.

Recently, Treated dentin matrix, an extracellular matrix-based biomaterial, has emerged as an excellent scaffold for tissue engineering because of its remarkable biological induction activity, distinct natural structure, and biocompatibility. In addition to having a high level of bioactivity, a treated dentin matrix can work as a transporter for bioactive substances and medication molecules, aiding in the processes of tissue regeneration and immunomodulation. Similar products such as demineralized bone matrices (DBMs) and other allograft bone materials have already found their place in clinical practice.

Comparative evaluation of calcium silicate-doped treated dentin matrix and mineral trioxide aggregate as miniature pulpotomy biomaterials in deep carious lesions: a parallel, double-blind, randomized clinical trial.

AIM:

To compare the efficacy of a Novel calcium silicate doped treated dentin matrix and Mineral Trioxide aggregate as biomaterials for miniature pulpotomy.

OBJECTIVES:

Primary objective:

To evaluate the efficacy of calcium silicate-doped human-treated dentin matrix (CaSi+hTDM) compared to Mineral Trioxide Aggregate (MTA) in maintaining pulp vitality using cold testing following Miniature Pulpotomy (MP) in deep and extremely deep carious lesions with reversible pulpitis in 14- to 35-year-old patients reporting to Department of Dentistry, AIIMS Nagpur.

Secondary objectives:

1. To evaluate patient-reported outcomes such as pain, swelling, sinus tract etc. post-operatively. 2. To determine the clinical success rates of both materials by assessing the Periapical index of healing over a 6 months follow-up period.

NULL HYPOTHESIS:

The null hypothesis (H0) is that there is no difference between CaSi+hTDM and MTA in maintaining pulp vitality when used as a Miniature Pulpotomy (MP) biomaterial in carious lesions.

Literature Review:

Vital pulp therapy is defined as a treatment aimed at conserving and sustaining compromised dental pulp tissue that has been impacted by extensive dental caries, dental trauma, and restorative interventions. or due to other iatrogenic reasons. Pulp preservation and vital pulp therapies have taken center stage in the last few years. It is important to take into consideration the entire history and genesis of pulp preservation techniques along with the newer ones that are becoming popular. Pulp preservation techniques are quite old, with reports of gold being placed directly over the injured pulp by Pfaff in the 18th century. In the early nineteenth century, the concept of pulp capping primarily revolved around the belief that pulpal healing took place solely following the etching and cauterization of the pulp. Numerous breakthroughs in the realms of medicine and technology, such as the discovery of microorganisms by Robert Hooke and Antoni van Leeuwenhoek, role of microorganisms in pathogenesis of various diseases by Pasteur and Lister, the introduction of dental radiographs in 1895 and development of anesthesia by Horace Wells and Willian Morton, has tremendously helped shape our understanding of the physiology of the pulp as well as pathology and treatment of pulpal and periapical diseases. The first clinical scientific study comparing different pulp capping materials done by Dätwyler demonstrated that zinc oxide eugenol showed the best results. After the introduction of Calcium hydroxide by Herman in 1920, numerous studies were conducted, indicating its biocompatibility when applied over vital pulp. Despite the perception in the early 1900s that an exposed pulp was deemed a 'doomed organ', it was not until research investigating pulp healing and pulpal responses to injuries and pulp capping materials were carried out, which helped in elevating our understanding of the injured pulp while also showing the unpredictability of outcomes for direct pulp capping. Success rates at that time were about 60-70% for direct pulp capping compared with 80-90% for RCT. Vital pulp treatments using calcium hydroxide had several drawbacks, such as inadequate adherence to dentin, gradual dissolution over time, and microleakage issues. However, with the introduction of Calcium silicate cements and improvement of our understanding of pulpal repair, there has been a profound change in our perspective regarding vital pulp therapies and hence this has translated to good clinical results for pulp capping and pulpotomy. Numerous great reviews have been done on the subject of Vital pulp therapies and their future directions.

Newer Definitions of VPT have been simplified to include all; 'Strategies aimed at maintaining the vitality of the pulp'. This includes one- and two-step selective caries removal techniques and indirect pulp capping to avoid pulp exposure as well as direct pulp capping and pulpotomy procedures. Recent position statements from the AAE and the ESE have provided conflicting recommendations for VPT's. The ESE position statement recommends 'selective carious-tissue removal (one-stage or two-stage stepwise technique) in teeth with reversible pulpitis, provided radiographic assessment indicates caries has progressed no deeper than the pulpal quarter with a zone of dentin separating the carious lesion from the pulp chamber'. On the contrary, the AAE recommends that 'complete caries removal is essential to eliminate infected tissues and visualize pulp tissue conditions under magnification when pulpal exposures occur. Residual caries compromises necessary observations of pulpal inflammation levels for a diagnosis of more severe pulpitis'. In instances when pulpitis was more severe, the ESE recommended that 'carious exposure with symptoms indicative of irreversible pu