Pulpal repair after direct pulp capping with new bioceramic materials: A comparative histological study

Tissue engineering approaches for dental pulp regeneration: The development of novel bioactive materials using pharmacological epigenetic inhibitors

The drive for minimally invasive endodontic treatment strategies has shifted focus from technically complex and destructive root canal treatments towards more conservative vital pulp treatment. However, novel approaches to maintaining dental pulp vitality after disease or trauma will require the development of innovative, biologically-driven regenerative medicine strategies. For example, cell-homing and cell-based therapies have recently been developed in vitro and trialled in preclinical models to study dental pulp regeneration. These approaches utilise natural and synthetic scaffolds that can deliver a range of bioactive pharmacological epigenetic modulators (HDACis, DNMTis, and ncRNAs), which are cost-effective and easily applied to stimulate pulp tissue regrowth. Unfortunately, many biological factors hinder the clinical development of regenerative therapies, including a lack of blood supply and poor infection control in the necrotic root canal system. Additional challenges include a need for clinically relevant models and manufacturing challenges such as scalability, cost concerns, and regulatory issues. This review will describe the current state of bioactive-biomaterial/scaffold-based engineering strategies to stimulate dentine-pulp regeneration, explicitly focusing on epigenetic modulators and therapeutic pharmacological inhibition. It will highlight the components of dental pulp regenerative approaches, describe their current limitations, and offer suggestions for the effective translation of novel epigenetic-laden bioactive materials for innovative therapeutics.

Different pulp capping agents and their effect on pulp inflammatory response: A narrative review

Several factors can directly damage dental pulp. Pulp healing requires controlled inflammation, which can be directed through specialized medical materials to eliminate infection and promote pulp repair. This review aimed to categorise these materials and identify their histological and molecular effects on pulp tissue or isolated cells in culture. In addition, we sought to identify which of these materials could trigger a favourable inflammatory pathway that could direct the pulpal response toward healing and regeneration. A single database (PubMed) was used, and the search strategy was based on MeSH terms. The search was conducted for articles published in English between January 2010 and December 2023, including those with histological and molecular findings. Only 33 articles met our inclusion criteria. Several conventional pulp capping agents have been shown to induce pulp healing and repair through dentine bridge formation. These materials show varying degrees of inflammation, ranging from moderate to mild, which may diminish over time. Other experimentally developed materials were also studied, either alone or in combination with conventional products; these materials demonstrated promising potential to reduce inflammation and superficial necrosis associated with conventional products. However, they still do not meet all the criteria for ideal pulp-capping materials and need further development for commercialisation. Several inflammatory pathways were also addressed in this review, along with favourable tissue responses to induce pulp regeneration. The immunomodulatory role of M2 phenotype macrophages is currently the most accepted, though the lack of standardised experimental procedures across studies hinder precise decision-making.

Biological evaluation of novel phosphorylated pullulan-based calcium hydroxide formulations as direct pulp capping materials: An in vivo study on a rat model

AIM

Calcium hydroxide (CH) has been considered as a direct pulp capping materials (DPC) for the last decades despite having some limitations. Phosphorylate pullulan (PPL) incorporated with CH (CHPPL) is a novel biomaterial that was introduced as a promising DPC material. Thus, the aim of the study was to evaluate the inflammatory response and mineralized tissue formation (MTF) ability of PPL-based CH formulations on rat molars after DPC.

METHODOLOGY

This study consisted of six groups: CH with 1% PPL (CHPPL-1); 3% PPL (CHPPL-3); 5% PPL (CHPPL-5); Dycal and NEX MTA Cement (N-MTA) as the positive control, and no capping materials (NC). One hundred twenty maxillary first molar cavities were prepared on Wistar rats. After capping, all the cavities were restored with 4-META/MMA-TBB resin and pulpal responses were evaluated at days 1, 7, and 28. Kruskal-Wallis followed by Mann-Whitney U-test was performed with a significance level of 0.05. Immunohistochemical expression of IL-6, Nestin, and DMP-1 was observed.

RESULTS

At day 1, CHPPL-1, N-MTA, and Dycal exhibited no to mild inflammation, whilst CHPPL-3, CHPPL-5, and NC showed mild to moderate inflammation, and the results were significantly different (p < .05). At day 7, mild to moderate inflammation was observed in CHPPL-1, N-MTA, and Dycal, whereas CHPPL-3, CHPPL-5, and NC exhibited moderate to severe inflammation. Significant differences were observed between CHPPL-1 and N-MTA with NC (p < .05), CHPPL-1 and CHPPL-3 with CHPPL-5 and Dycal (p < .05), and CHPPL-3 with N-MTA (p < .05). A thin layer of mineralized tissue formation (MTF) was observed in all groups. At day 28, CHPPL-1, Dycal, and N-MTA showed no to mild inflammation, whilst CHPPL-3, CHPPL-5, and NC exhibited mild to severe inflammation, and statistically significant difference was detected (p < .05). CHPPL-1, Dycal, and N-MTA exhibited continuous MTF, whilst CHPPL-3, CHPPL-5, and NC had thicker and interrupted MTF. Significant differences were observed between CHPPL-1, CHPPL-3, and N-MTA with NC group (p < .05). Variable expressions of IL-6, Nestin, and DMP-1 indicated differences in the materials' impact on odontoblast-like cell formation and tissue mineralization.

CONCLUSIONS

These findings suggest that CHPPL-1 has the potential to minimize pulpal inflammation and promote MTF and had similar efficacy as MTA cement.

The Management of Hyperplastic Pulpitis in Immature Permanent Molar Using Vital Pulp Therapy: A Case Report with 12 Months Follow-Up

Hyperplastic pulpitis is an irreversible type of pulpitis that primarily affects young patients. It occurs when an inflamed pulp becomes exposed due to factors such as dental caries, dental trauma, or other causes. Root canal treatment is commonly employed to manage hyperplastic pulpitis. However, vital pulp therapy can be considered as a less invasive option. The main objective of this treatment is to preserve the vitality and functionality of the remaining pulp tissue. This case report discusses the potential management of hyperplastic pulpitis in an immature molar using vital pulp therapy instead of a full root canal treatment. The report includes clinical and radiographic follow-up at six and twelve months.

A paradigm shift from calcium hydroxide to bioceramics in direct pulp capping: A narrative review

For many years, calcium hydroxide (CH) was the preferred material for direct pulp capping (DPC), occupying an elevated position. The collapse of this paradigm is due to the emergence of bioceramics with less pulpal inflammation and superior mineralization abilities than CH. The goal of the current article was directed to: (1) review the history of DPC "the idea of an exposed pulp as a hopeless organ has given way to one of healing and optimism," (2) classify the bioceramics in dentistry, and (3) explain and compare the mechanism by which dentin barriers for CH and bioceramics are formed. A comprehensive literature search of the database was conducted using PubMed, Google Scholar, and Scopus utilizing the following terms: Biodentine, calcium hydroxide, calcium aluminate, calcium phosphate, calcium silicate, direct pulp capping, NeoMTA Plus, Quick-Set2, and TotalFill. Reference mining of the selected publications was utilized to discover other studies and strengthen the results. Only works written in English were taken into consideration, and there were no restrictions on the year of publication. Bioceramic materials might be used as an intriguing substitute for CH. Compared to CH, they induced more positive pulpal reactions.

Advances and challenges in regenerative dentistry: A systematic review of calcium phosphate and silicate-based materials on human dental pulp stem cells

Conventional dentistry faces limitations in preserving tooth health due to the finite lifespan of restorative materials. Regenerative dentistry, utilizing stem cells and bioactive materials, offers a promising approach for regenerating dental tissues. Human dental pulp stem cells (hDPSCs) and bioactive materials like calcium phosphate (CaP) and silicate-based materials have shown potential for dental tissue regeneration. This systematic review aims to investigate the effects of CaP and silicate-based materials on hDPSCs through in vitro studies published since 2015. Following the PRISMA guidelines, a comprehensive search strategy was implemented in PubMed MedLine, Cochrane, and ScienceDirect databases. Eligibility criteria were established using the PICOS scheme. Data extraction and risk of bias (RoB) assessment were conducted, with the included studies assessed for bias using the Office of Health and Translation (OHAT) RoB tool. The research has been registered at OSF Registries. Ten in vitro studies met the eligibility criteria out of 1088 initial studies. Methodological heterogeneity and the use of self-synthesized biomaterials with limited generalizability were observed in the included study. The findings highlight the positive effect of CaP and silicate-based materials on hDPSCs viability, adhesion, migration, proliferation, and differentiation. While the overall RoB assessment indicated satisfactory credibility of the reviewed studies, the limited number of studies and methodological heterogeneity pose challenges for quantitative research. In conclusion, this systematic review provides valuable insights into the effects of CaP and silicate-based materials on hDPSCs. Further research is awaited to enhance our understanding and optimize regenerative dental treatments using bioactive materials and hDPSCs, which promise to improve patient outcomes.

Biomimetic Approaches in Clinical Endodontics

In the last few decades, biomimetic concepts have been widely adopted in various biomedical fields, including clinical dentistry. Endodontics is an important sub-branch of dentistry which deals with the different conditions of pulp to prevent tooth loss. Traditionally, common procedures, namely pulp capping, root canal treatment, apexification, and apexigonesis, have been considered for the treatment of different pulp conditions using selected materials. However, clinically to regenerate dental pulp, tissue engineering has been advocated as a feasible approach. Currently, new trends are emerging in terms of regenerative endodontics which have led to the replacement of diseased and non-vital teeth into the functional and healthy dentine-pulp complex. Root- canal therapy is the standard management option when dental pulp is damaged irreversibly. This treatment modality involves soft-tissue removal and then filling that gap through the obturation technique with a synthetic material. The formation of tubular dentine and pulp-like tissue formation occurs when stem cells are transplanted into the root canal with an appropriate scaffold material. To sum up tissue engineering approach includes three components: (1) scaffold, (2) differentiation, growth, and factors, and (3) the recruitment of stem cells within the pulp or from the periapical region. The aim of this paper is to thoroughly review and discuss various pulp-regenerative approaches and materials used in regenerative endodontics which may highlight the current trends and future research prospects in this particular area.

Direct pulp capping with autologous bone marrow derived stem cells in dogs

Bone-marrow derived stem cells (BMSCs) can differentiate into several mesenchymal cell lines that are suitable for bone and dental tissue engineering. This study was aimed to assess the efficacy of cell therapy in direct pulp capping (DPC) of canine teeth using autologous BMSCs along with collagen/hydroxyapatite hybrid scaffold in terms of the quantity and quality of calcified bridge formation. The teeth were randomly divided into three groups of DPC with mineral trioxide aggregate (MTA), hydroxyapatite/collagen hybrid scaffold alone and BMSCs with hydroxyapatite/collagen hybrid scaffold. DPC was performed under general anesthesia in cavities prepared on the buccal surfaces of mandibular and maxillary premolars of the same dogs from which, stem cells had been isolated. All cavities were then restored with light-cure resin modified glass ionomer cement. Histomorphometric assessments after 12 weeks showed formation of dentinal bridge following DPC with BMSCs and MTA. The efficacy of MTA for calcified bridge formation following DPC was significantly higher than that of BMSCs plus hybrid scaffold. According to the present study, we concluded DPC using BMSCs and hybrid scaffold did not provide clinically noticeable results in canine patients.

A prospective clinical study with one year follow up of deep caries management using a novel biomaterial

OBJECTIVES

The objectives of this study was to check the outcome of the direct and indirect pulp capping procedure using MTA (Mineral Trioxide Aggregate) by comparing the pre-and post-operative pain by using VAS scale, associating the pre- and post- operative changes in intraoral periapical radiograph and clinical symptoms.

MATERIALS AND METHODS

In this prospective clinical study 10 cases (5 for direct and 5 for indirect) with deep carious lesions (symptomatic) with no periapical changes were selected for the trial. The participants were subjected to deep caries management procedure under rubber dam where MTA is placed as pulp capping material followed by immediate restoration with sandwich technique using composite resin. The participants were followed up at recall visits of 1 month, 3 months, 6 months and 1 year intervals for clinical and radiographic evaluation.

RESULTS

The results of the study, analyzing the VAS, clinical symptoms and radiographic changes did not show any signs of pain, clinical and radiographic symptoms at 1 month, 3 months, 6 months and 1 year intervals.

CONCLUSIONS

It was concluded that MTA can be used for deep caries management as a pulp capping material which being equivalent to calcium hydroxide.

A critical analysis of research methods and experimental models to study biocompatibility of endodontic materials

Materials used for endodontics and with direct contact to tissues have a wide range of indications, from vital pulpal treatments to root filling materials and those used in endodontic surgery. In principle, interaction with dental materials may result in damage to tissues locally or systemically. Thus, a great variety of test methods are applied to evaluate a materials' potential risk of adverse biological effects to ensure their biocompatibility before commercialization. However, the results of biocompatibility evaluations are dependent on not only the tested materials but also the test methods due to the diversity of these effects and numerous variables involved. In addition, diverse biological effects require equally diverse assessments on a structured and planned approach. Such a structured assessment of the materials consists of four phases: general toxicity, local tissue irritation, pre‐clinical tests and clinical evaluations. Various types of screening assays are available; it is imperative to understand their advantages and limitations to recognize their appropriateness and for an accurate interpretation of their results. Recent scientific advances are rapidly introducing new materials to endodontics including nanomaterials, gene therapy and tissue engineering biomaterials. These new modalities open a new era to restore and regenerate dental tissues; however, all these new technologies can also present new hazards to patients. Before any clinical usage, new materials must be proven to be safe and not hazardous to health. Certain international standards exist for safety evaluation of dental materials (ISO 10993 series, ISO 7405 and ISO 14155‐1), but researchers often fail to follow these standards due to lack of access to standards, limitation of the guidelines and complexity of new experimental methods, which may cause technical errors. Moreover, many laboratories have developed their testing strategy for biocompatibility, which makes any comparison between findings more difficult. The purpose of this review was to discuss the concept of biocompatibility, structured test programmes and international standards for testing the biocompatibility of endodontic material biocompatibility. The text will further detail current test methods for evaluating the biocompatibility of endodontic materials, and their advantages and limitations.

Pulpal response to mineral trioxide aggregate containing phosphorylated pullulan-based capping material

This study aimed to evaluate the pulpal responses of monkey's pulp after direct pulp capping (DPC) with the novel mineral trioxide aggregate containing phosphorylated pullulan-based material (MTAPPL). Seventy-two teeth were randomly divided into four groups: MTAPPL; Nex-Cem MTA (NX); TheraCal LC (TH); and Dycal (DY). Histopathological changes in the pulps were observed at days 3, 7 and 70. On day 3, mild inflammatory responses were observed in the MTAPPL, no to moderate inflammatory responses in the TH, whereas moderate inflammatory responses in the NX and DY. No mineralized tissue formation (MTF) was observed in all groups. On day 7, no or mild inflammatory responses were observed in all groups. Initial MTF was observed except for DY. No inflammation with complete MTF including presence of odontoblast-like cells was observed in the MTAPPL, NX and TH groups at day 70. These findings indicate that MTAPPL could be an efficient DPC material.

Histological evaluation of a novel phosphorylated pullulan-based pulp capping material: An in vivo study on rat molars

AIM

To evaluate the dental pulp response to a novel mineral trioxide aggregate containing phosphorylated pullulan (MTAPPL) in rats after direct pulp capping.

METHODS

Ninety-six cavities were prepared in the maxillary first molars of 56 male Wistar rats. The dental pulps were intentionally exposed and randomly divided into four groups according to the application of pulp capping materials: MTAPPL; phosphorylated pullulan (PPL); a conventional MTA (Nex-Cem MTA, NCMTA; positive control); and Super-Bond (SB; negative control). All cavities were restored with SB and observed for pulpal responses at 1-, 3-, 7- and 28-day intervals using a histological scoring system. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U-test with Bonferroni's correction, and the level of significance was set at 0.05. DMP1 and CD34 antigen were used to evaluate odontoblast differentiation and pulpal vascularization, respectively.

RESULTS

On day 1, mild inflammatory cells were present in MTAPPL and NCMTA groups; fewer inflammatory cells were present in the PPL, whereas SB was associated with a mild-to-moderate inflammatory response. A significant difference was observed between PPL and SB (p < .05). No mineralized tissue deposition was observed. On day 3, moderate-to-severe inflammatory cells were present in PPL and SB, whereas MTAPPL and NCMTA had a mild inflammatory response. Initial mineralized tissue deposition was observed in the NCMTA, MTAPPL and SB. A significant difference was observed between MTAPPL and PPL (p < .05). On day 7, a thin layer of mineralized tissue was observed in all tested groups with no or mild inflammatory response. On day 28, no inflammatory response was observed in MTAPPL, whereas NCMTA, PPL and SB had mild inflammatory responses. A significant difference was observed between MTAPPL and SB (p < .05). Complete mineralized tissue barrier formation was observed in MTAPPL, NCMTA and PPL with no significant difference (p > .05). SB exhibited incomplete mineralized tissue barriers, significantly different from NCMTA, MTAPPL and PPL (p < .05). The staining with CD34 was positive in all the groups on all observation days.

CONCLUSION

The favourable pulpal responses and induction of mineralized tissue formation associated with MTAPPL indicate its potential application as a direct pulp capping material.

Premixed bioceramics: A novel pulp capping agent

The main aim of restorative dentistry is to protect the vitality of the Pulp tissue. The pin point carious expoure and iatrogenic errors warrant the need for various pulp capping procedures like Indirect Pulp Capping and Direct Pulp Capping. Pulp Capping is dressing of the dental pulp exposed due to mechanical procedure, carious lesion or traumatic injury to preserve its vitality and function. There has been constant evolution and research on materials used to cap the Pulp tissue. The different kind of chemical and biological materials has been used with varying degree of success. The prognosis based on the pulp capping material has dramatically improved with the introduction of bioactive cement. Though MTA and biodentine have shown a high success rate, their properties can be adversely affected with error in powder/liquid ratio and may present with difficulty in the handling characteristic. Premixed bioceramics have been introduced in the market and present with desirable properties as a pulp capping agent. Owing to good handling characteristics, biocompatibility, odontogenic property, and antibacterial action it is a potent pulp capping agent for clinical application. This review is aimed to discuss the introduction of premixed bioceramics, forms of premixed bioceramics available, and its physical, chemical, and biocompatible properties.

Efficacy of different calcium silicate materials as pulp-capping agents: Randomized clinical trial

Background/purpose

Calcium hydroxide-based materials were the gold standard in vital pulp therapies for decades' despite of several shortcomings. However, calcium silicates have been discussed as an alternative to overcome these drawbacks. It was aimed to investigate the in-vivo effectiveness of different calcium silicates based materials in pulp capping in this study.

Materials and methods

A parallel-design, randomized controlled trial with 213 patients who has deep dentin caries, vital pulps and without spontaneous pain or history of swelling was designed. 525 M teeth were randomized, blinded and allocated to one of the five groups for pulp capping treatment (n = 105). All teeth were followed up clinically and radiographically (after 1st, 6th, 12th and 36th months) by blinded investigators. The clinical and radiographic success, and the effect of the pulp exposure to the success rate analyzed with Wald chi-square and Z tests.

Results

Clinical and radiographic success of MTA+ (86.3%, 85.4%) and Biodentine (79.4%, 80.1%) were found the highest. Although results of Theracal LC group (72.1%, 73.6%) were better than Dycal group (69.4%, 70.2%), the difference was nonsignificant (p > 0.05). Only in light-cured groups, (TheraCal LC & LC Calcihyd) pulpal exposure size effected the success of the materials (p < 0.05). MTA+ and Biodentine resulted better scores, when compared with TheraCal LC in large pulpal exposures (p < 0.05).

Conclusion

After 36-month follow-up, both MTA+ and Biodentine were found to be the appropriate material for direct pulp capping in permanent teeth. The filler ingredient of the Theracal-LC eases the usage of calcium silicates but decreases the success rate.