To Evaluate and Compare Platelet-rich Fibrin and Mineral Trioxide Aggregate as Direct Pulp Capping Agents in Primary Molars: A Randomized Prospective Clinical Study

Abstract

Aim

This study aimed to evaluate and compare the clinical and radiographic success of platelet-rich fibrin (PRF) and mineral trioxide aggregate (MTA) as direct pulp capping (DPC) agents in primary molars.

Materials and methods

In this study, 50 primary first and second molars from healthy children aged 5–9 years requiring pulp therapy were randomly allocated into two groups. In the PRF group, after coronal pulp removal and hemostasis, the remaining pulp tissue was covered with PRF preparation. In the MTA group, after coronal pulp removal and hemostasis, MTA was placed, followed by a zinc oxide eugenol (ZOE) base and glass ionomer cement (GIC) in both groups. Clinical and radiographic evaluations were undertaken at 1-, 3-, 6-, 9-, and 12-month intervals.

Results

By the end of the 12th month, the overall success rate was 82.6% in the PRF group, whereas it was 61.9% in the MTA group.

Conclusion

Platelet-rich fibrin can be used successfully as an appropriate alternative material in DPC of primary teeth when compared with MTA.

How to cite this article

Tiwari T, Tyagi P, Tiwari S, et al. To Evaluate and Compare Platelet-rich Fibrin and Mineral Trioxide Aggregate as Direct Pulp Capping Agents in Primary Molars: A Randomized Prospective Clinical Study. Int J Clin Pediatr Dent 2024;17(S-1):S25–S29.

Introduction

Dental caries is a type of infection that triggers a complicated relationship between the tooth's defense mechanisms, regenerative processes, and overall response.¹ An inflammatory response will be produced in the coronal pulp of a primary molar if it is carious and left untreated or treated inadequately, allowing bacteria to invade the pulp. Preserving the health and functionality of the oral cavity is the principal objective of pulp therapy. For dentists, the most difficult task is diagnosing pulp conditions and determining whether they can be controlled with conservative treatment. A pulpectomy, pulpotomy, or direct pulp capping (DPC) are the options available for conservative pulp therapy. Comparing DPC to other endodontic treatment modalities, it is less invasive. However, compared to permanent teeth, there are more restrictions on deciduous teeth.^2–6

Calcium hydroxide, which is the most frequently employed pulp capping material, was shown to be significantly less effective in primary teeth than in permanent teeth. This can be explained by the pulp structure of primary teeth, which exhibits a high density of nondifferentiated mesenchymal cells that have the potential to become odontoclasts and cause internal resorption of dental tissues.^6–8

Mineral trioxide aggregate (MTA), known for its exceptional physicochemical properties, was investigated as a potential medication in direct pulp therapy. There are some drawbacks regardless of its many advantages, such as high solubility, toxins present in the material, high pH after setting, messy handling, elevated setting time, increased cost, and discoloration in both grey and white forms.⁹

We require an agent that can be both cost-effective and enhance the natural healing process in pulp regeneration to overcome these drawbacks. Therefore, it is critical to develop biocompatible therapies that preserve pulp vitality and increase tooth longevity.^10–13 Search in this area has led to the use of new regenerative agents like platelet rich fibrin (PRF). Research in this area has led to the use of new regenerative agents like platelet-rich fibrin (PRF). PRF contains a variety of growth factors, such as transforming growth factor β1, insulin-like growth factor, and platelet-derived growth factor. These factors exhibit strong specific properties, including cell migration, differentiation, attachment, and proliferation. It contributes significantly to various scientific fields, particularly in the clinical utilization of regenerative endodontics, including bone regeneration, apexogenesis, revascularization, and pulp capping.¹⁴ However, there is insufficient literature on the DPC of primary teeth using PRF. Considering this gap, the main objective of the current study was to assess the effectiveness of PRF as a DPC agent compared to MTA, both clinically and radiographically.

Materials and Methods

Ethical Clearance and Consent

Ethical clearance was issued by the Institutional Ethics Committee. Guardians of the children were provided with comprehensive information about the benefits, treatment, and potential risks involved in the procedure. In the PRF group, blood was drawn from each patient, and written consent was obtained from the guardians prior to treatment.

Study Design and Sampling

The study was conducted on carious primary first and second molars of child patients aged 5–9 years who visited the outpatient department (OPD) in the Department of Pediatric and Preventive Dentistry, People's College of Dental Science and Research Center, Bhopal, Madhya Pradesh, India.

A total of 50 primary molars requiring pulp therapy were selected. Random selection was used to assign each tooth to either of the two treatment groups, PRF or MTA. A power analysis was carried out, with 25 teeth in each group, to ensure a sufficient number of samples were gathered, showing 80% power and 5% significance. All treatments and diagnoses were performed by a single operator.

The teeth were selected based on the following criteria: clinically, there were no symptoms or any signs of pathological mobility, teeth with no response to cold and pressure stimuli, and no presence of edema or sinus. Radiographically, carious dentin was observed to contact the pulp, with no minimal evidence of furcation or internal root resorption/apical pathology canal calcification. With little evidence of internal root resorption, furcation/apical pathology, or canal calcification, radiographically, there was only carious dentin in contact with the pulp. After the treatment is finished, teeth should be restorable.

Exclusion criteria included teeth clinically demonstrating tenderness to percussion, spontaneous pain, sinus tract, or presence of radiographic pathology. Participants with immunocompromised conditions, congenital heart defects, leukemia, or a history of heart surgery were also excluded from the study.

Procedure

A combination of 1:1,00,000 adrenaline and 2% lidocaine was used to administer local anesthesia. A rubber dam was applied to isolate the tooth. After outlining the cavity with water coolant and a high-speed round diamond bur, caries were excavated using a spoon excavator. Normal saline (0.9% w/v) was used to remove debris. After achieving pinpoint exposure to the pulp (>1 mm), hemorrhage was controlled using a sterile pledget of moist cotton with pressure.

Platelet-rich Fibrin

After hemorrhage was controlled, PRF preparation was performed according to Choukroun's protocol in the PRF group.¹⁵ The required amount of blood was collected by a technician into 10 mL test tubes for centrifugation at 2,700 rounds per minute for 12 minutes. The resultant product exhibited three layers—the PRF clot was obtained from the middle of the vacutainer and retrieved with the help of sterile tweezers. Using dry gauze, the platelet fibrin membrane was extracted from the PRF. A sterile pledget made of moist cotton was used to gently pack the freshly prepared fibrin membrane over the pulp stumps in this case.

Mineral Trioxide Aggregate

The pulp stump was covered with MTA (Angelus—fast setting). According to the manufacturer's instructions, a paste was prepared by mixing MTA powder with sterile water at a ratio of 3:1.^16–18 The remaining cavities in both groups were filled with reinforced non-eugenol zinc oxide cement followed by glass ionomer cement (GIC) as the final restoration. After applying the mixture and patting it down with moist cotton pellets, clinical examinations were conducted at 1-, 3-, 6-, 9-, and 12-month intervals, while radiographic examinations of the treated teeth were performed every 6 months. After 7 days of the procedure, the patients’ parents were contacted via telephone and asked if the children had experienced pain or adverse reactions related to the treatment.

At every follow-up appointment, DPC was considered clinically successful if treated primary molars exhibited no pain, tenderness to percussion, swelling, abscess, or abnormal tooth mobility. Radiographically, successful evaluation was determined by the absence of furcation involvement, periapical radiolucency, pathological external root resorption, or internal resorption. The absence of any negative clinical symptoms or radiographic pathology indicated the complete clinical and radiographic success of the treatment. Treatment was considered a failure when—(1) at least one adverse clinical finding was present or (2) in the presence of severe radiographic pathology with or without adverse clinical findings.

Statistical Analysis

Data comparison was conducted by applying specific statistical tests to determine the statistical significance of the comparisons. Data were entered in the form of numbers and percentages. The Chi-squared test was used to compare proportions for all clinical and radiographic criteria, with a significance level set at p < 0.005 to adjust for multiple comparisons (Table 1).

Table 1:

Chi-squared tests for comparison of the two groups

		N	Group				Chi-square	p-value
			PRF		MTA
			Count	Column N%	Count	Column N%
Gender	Male	35	22	88.00%	13	52.00%	7.714	0.005
	Female	15	3	12.00%	12	48.00%
Age	5–6 years	16	6	24.00%	10	40.00%	1.471	0.225
	7–9 years	34	19	76.00%	15	60.00%
Success/failure	Failure	12	4	17.40%	8	38.10%	2.372	0.124
	Success	32	19	82.60%	13	61.90%

No clinical findings were observed in either of the groups initially. Furthermore, there were no clinical findings in either group for up to 1 month. After 3 months, one patient in the MTA group reported pain.

Results

A total of 50 teeth were treated, and follow-up evaluations were conducted at 1, 3, 6, 9, and 12 months postpulp capping. At the 6-month interval, one patient in each group reported pain, but this was not statistically significant (p > 0.05). The incidence of pain was noted in 3.7% of the total cases.

After the 6th month, two primary molars were lost during follow-up, leaving a total of 24 patients available in each group. Overall, 1.24% mobility was observed in both groups in the MTA group; it was seen at 6 and 12 months in two patients, whereas only one patient showed mobility in the PRF group. Clinically, soft tissue swelling was noticed in one patient in the MTA group at 12 months. This comparison was not statistically significant with a p-value.

On the 9th month, 5.3% of teeth in the MTA group and 1.6% in the PRF group showed furcal radiolucency and internal resorption, but these findings were not statistically significant (p > 0.05).

External resorption was noticed in one tooth in the MTA group in the 6th month and in the PRF group in the 9th month. Cases that showed clinical or radiological findings are considered failures.

Overall, after the final 12-month follow-up, the success rate was 82.6% in the PRF group compared to 61.9% in the MTA group. There were four failures in the PRF group (17.4%) and eight failures in the MTA group (38.1%) after 12 months of follow-up. However, this comparison was not statistically significant (p = 0.124, p > 0.005).

On comparison of PRF and MTA groups in relation to the parameter age, there are 16 (5–6) years and 34 (7–9) years numbers in each category. The number of 5–6 years is higher in the MTA group, with a percentage of 24. The 7–9 years category is higher in the PRF group, with a percentage of 76. This comparison is statistically insignificant, with a p-value of 0.225.

Discussion

This study aimed to evaluate the success of MTA and PRF used as DPC materials in primary molar teeth. The age-groups were chosen with consideration for the uncooperative nature of children under 4 years old and physiological root resorption (>3/4 of the root) in children over 9 years old.^19,20 Both MTA and PRF were used as pulp capping therapy in child patients aged 5–9 years in our study because they are utilized in regenerative vital pulp capping treatments. Preventing microorganisms from entering the pulp and controlling bleeding are essential factors for successful DPC. Therefore, rubber dams were employed for strict isolation in the current study, and pressure was applied while moistening cotton pellets with sterile saline to achieve complete hemostasis.²¹

Asymptomatic pulp was a requirement in the present investigation for inclusion in DPC. Kennedy and Kapala noted that failures of DPC in primary teeth may be associated with the highly cellular structure of primary pulp tissue.²² The authors additionally pointed out that pulp capping materials susceptible to internal resorption, or the caries process, could cause undifferentiated mesenchymal cells to differentiate into odontoclastic cells.

There are various medications used as DPC agents, but in our examination, we are comparing MTA with PRF, which previous literature has found to be suitable materials.^16,23–25

Mineral trioxide aggregate is biocompatible and possesses good sealing properties. It has been shown to induce the release of cytokines from bone cells, actively promoting the development of hard tissue. Several studies have demonstrated MTA's efficacy as a material for pulp capping in primary teeth. Excellent tissue healing has been observed over the lifespan of primary teeth, with no adverse effects noted on exfoliation or the eruption of permanent teeth.^16,23–25

This has been confirmed by Glass and Zander's study, which reported the development of dentin bridges in six cases of DPC and seven cases of pulpotomy using MTA. Additionally, MTA stimulates the release of bone-like cells, actively promoting the development of hard tissue.²⁶ According to Ford et al., MTA may be superior because of its strong sealing ability and biocompatibility, which is also supported by the results of our study.²⁷ Few studies describing the outcomes of DPC in primary dentition with MTA as a successful agent have been published in the past literature, and these studies are fairly similar to ours. Among the 21 patients who were followed up, 13 (61.9%) had successful outcomes.

The first researchers to publish a case report on the direct capping of a 7-year-old boy's primary first molar with MTA were Bodem et al. Around 18 months following treatment, they saw no pathological clinical or radiographic findings.⁸ In DPC, Caicedo et al. and Kotsanos et al. attained 80 and 88.3% success rates, respectively.^28,29 However, following a 24-month observation, Aminabadi et al. saw an overall success rate of above 90%, and Tuna et al. saw favorable results in all 22 primary molars.^30,31 Consequently, our results align with the findings of related research.

While MTA has benefits as a pulp therapy agent, it also has some drawbacks, such as the pH of 12.5 produced in its vicinity, which remains high for at least 8 weeks. It has been found that the high pH of MTA during setting inhibits cell growth and can cause cytotoxic effects on fibroblasts and macrophages.³² Thus, it is essential to evolve biocompatible therapy that maintains pulp vitality and increases tooth longevity.³³

Platelet-rich fibrin, a second-generation platelet concentrate, is an autologous biomaterial composed of platelets, leukocytes, and various vital healing proteins within a dense fibrin matrix. PRF exhibits an immune concentrate with a distinct composition and three-dimensional architecture. It contains numerous potent local characteristics, including cell migration, attachment, proliferation, and differentiation. Key growth factors present in PRF include insulin-like growth factor, platelet-derived growth factor, and transforming growth factor β1.³⁴ These findings support the present investigation, which focuses on PRF's role as a pulp capping agent in primary teeth.

Very few studies have reviewed the use of PRF matrix as a pulpotomy agent, and to date, no clinical studies have been conducted. The investigators advise that longer-term trials with larger sample sizes are necessary to support the use of PRF for the treatment of DPC in primary teeth.

The present study contrasted its findings based on the unique interactions of PRF used as a pulpotomy agent in vital pulp therapy for primary teeth. Before surgery, every patient in both the PRF and MTA groups complained of pain. After 6 months of follow-up appointments, a statistically significant difference was observed between the groups. Similar results were reported in the study conducted by Kalaskar and Damle, where all patients initially experienced pain, but a noticeable resolution of the pain was observed after 6 months.³⁵

In our findings, the success rate with PRF was 82.6%, which was slightly higher than MTA at 61.9%, though the difference was not statistically significant. The higher success rate in the PRF group could possibly be attributed to its autologous nature, lower cytotoxicity, and better healing properties in forming pulp tissue and dentine complex, as indicated by previous studies. Eight cases out of 50 teeth showed complications, with the majority occurring at least 3 months after treatment initiation. PRF had a failure rate of 17.4%, while MTA had a failure rate of 38.1% at the time of follow-up. The primary cause of failure in both the PRF and MTA groups was the challenging and uncertain diagnosis of pulp disease, particularly in younger children. The timing of restoration placement significantly influenced the success rate of exposed pulp healing. Therefore, resin-bonded zinc oxide eugenol (ZOE) was placed above the pulp capping and prior to permanent restorations. Other studies have also supported this conclusion. It was found that teeth receiving definitive restorations immediately after pulp capping had significantly fewer failures compared to those receiving them later.³⁵

Some authors suggest that bacterial contamination during treatment may have less impact on the outcome compared to bacterial leakage through the final restoration after a pulp capping procedure.^36,37 This result emphasizes the importance of a strong seal in the final restoration after pulp capping.

The primary disadvantage of PRF is that it requires manipulation to be placed inside the canal, which may have contributed to the failures observed in the current study. Since there has never been an in vivo study using PRF as a DPC material for primary molars, further research with histological collaboration is needed in this area to accurately determine the precise causes of failure. The findings of this study, which used PRF as a DPC agent, might be an important change in vital pulp therapy agents in the future.

Conclusion

When compared to MTA, PRF proved to be a more effective DPC agent. Currently, no research has been conducted using PRF in vivo as a DPC agent for primary teeth in the reviewed literature. Therefore, the study does not allow for cross-validation of PRF outcomes. With the current knowledge, PRF can be classified as a promising therapeutic biomaterial. Importantly, no child, regardless of age, became uncooperative during the pulp capping or blood draw processes. Consequently, it is reasonable to conclude that PRF has a promising future in the field of vital pulp therapy for primary teeth.

Orcid

Mydukur S Moudgalya https://orcid.org/0000-0001-9809-1390

Nandani Jaiswal https://orcid.org/0000-0003-3448-0594