Study Context and Objectives

Regenerative endodontic therapy (RET) of necrotic immature permanent teeth relies on the use of scaffolds capable of promoting the migration, proliferation, and differentiation of stem cells. While the induction of an intracanal blood clot has long been the standard, the limited release of growth factors has led to the adoption of autologous platelet concentrates. Injectable PRF (i-PRF) represents a recent advancement: it combines the fluidity required to adapt to complex canal anatomies with a high concentration of leukocytes and a sustained release of key growth factors (PDGF, EGF, IGF-1).

The objective of this prospective observational study is to evaluate and compare the clinical and radiographic outcomes of i-PRF versus classic PRF used as a matrix in RET. Conducted on a cohort of 38 teeth in patients aged 9 to 30 years, the study analyses the effectiveness of these two generations of concentrates over a one-year follow-up period.

The central hypothesis is based on the ability of i-PRF to outperform or equal PRF in achieving therapeutic goals: the elimination of symptoms and bone healing (primary objective), the increase in dentinal wall thickness and root length (secondary objective), as well as a positive response to pulp vitality tests (tertiary objective).

Design and population

This prospective observational study included 38 patients aged 9 to 30 years with non-vital permanent maxillary central incisors (trauma or caries) with an open apex. Participants were divided into two groups: i-PRF (n=19) and PRF (n=19).

Operating procedure

• Disinfection: Irrigation with 20 ml of 1.5% NaOCl followed by 20 ml of saline solution.
• Intracanal medication: Application of a modified triple antibiotic paste (MTAP) composed of metronidazole, clindamycin and ciprofloxacin (1:1:1 ratio) at a concentration of 1 mg/ml in propylene glycol, left in place for 4 weeks.
• Regeneration phase: After removal of the TAP and final irrigation with 17% EDTA, the concentrates were prepared (Duo Quattro centrifuge).
• Centrifugation parameters: The i-PRF group received a concentrate obtained at 700 rpm for 3 min (plastic tube); the PRF group used a clot obtained at 2700 rpm for 12 min (glass tube).
• Obturation: The matrices were placed 3 mm below the cemento-enamel junction (CEJ), covered with a collagen sponge, Biodentine and a composite restoration.

Evaluation and analyses

Follow-up was performed at 3, 6, and 12 months. Root length and dentin thickness measurements were conducted on standardized radiographs using ImageJ software. Statistical analysis utilized Fisher's exact test, Pearson's chi-square test, and the Mann-Whitney U test (p < 0.05).

Analysis of clinical and radiographic follow-up

The study reports a 100% follow-up completion rate for the 38 participants at the end of the 12-month period. The evaluations, based on AAE recommendations, focused on the following points:

• Primary objective: Total elimination of clinical symptoms (pain, sensitivity to percussion, edema) and bone healing confirmed by the PAI (Periapical Index) score.
• Secondary objective (Root maturation): Measurement of the increase in dentinal wall thickness and root length via ImageJ software, with readings at 50%, 66%, and 80% of the total root length.
• Tertiary objective (Revitalization): Evaluation of the pulp response by cold and electrical tests at 12 months.

i-PRF has demonstrated a superior ability to adapt to complex root canal anatomy thanks to its initial fluidity, while ensuring a sustained release of key growth factors (PDGF-AA, PDGF-AB, EGF, and IGF-1). The protocol used a statistical significance threshold of p < 0.05 to compare the two groups.

i-PRF vs PRF in regenerative endodontics: maneuverability at the service of revascularization", "discussion": "

Clinical performance analysis of i-PRF

The results of this prospective study highlight the clinical interest of i-PRF (injectable Platelet-Rich Fibrin) as a matrix for regenerative endodontic therapy (RET). Its fluidity constitutes a major advantage compared to traditional PRF: whereas the PRF clot must be manually cut and condensed at the risk of leaving empty spaces, i-PRF adapts perfectly to the complex anatomy of the root canal. This optimal adaptation, coupled with a high concentration of leukocytes and the sustained release of growth factors (PDGF-AA, PDGF-AB, EGF, IGF-1), appears to promote a micro-environment conducive to the migration and differentiation of apical stem cells.

Root maturation and study limitations

The study confirms that both types of autologous platelet concentrates achieve the primary (bone healing) and secondary (thickening of dentinal walls, root lengthening) objectives. However, the use of i-PRF simplifies the surgical protocol by avoiding the tedious steps in the PRF box. Nevertheless, although the 12-month follow-up shows total clinical success on the 38 treated teeth, the sample size (n=19 per group) and the observation period remain limited to evaluate the very long-term stability of this revitalization and the definitive pulp response (tertiary objective).

Implications for daily practice

This study demonstrates that i-PRF is not only an alternative to PRF, but a relevant technical evolution. The transition from centrifugation at 2700 rpm (12 min) for PRF to a short centrifugation of 700 rpm (3 min) for i-PRF reduces chair time while providing a malleable matrix. For the practitioner, this means a reduction in invasive manipulations within the root canal and better predictability of pulp space filling by the biological scaffold.

Optimizing the scaffold in regenerative endodontics: i-PRF vs PRF

The choice of scaffold is crucial for the migration and differentiation of stem cells in regenerative endodontics (RET). This prospective study compares two autologous approaches on 38 immature incisors: i-PRF (injectable, centrifuged at 700 rpm for 3 min) and classic PRF (membrane, 2700 rpm for 12 min). The clinical challenge lies in the ability of i-PRF to adapt via injection to complex root canal anatomy, while providing a high concentration of leukocytes and a sustained release of growth factors (PDGF, IGF-1).

In concrete terms, for the practitioner:

• Simplify insertion: Prioritize i-PRF for perfect coronal-apical adaptation; its initial fluidity allows for saturation of the endodontic space before its in situ coagulation (10-15 min), avoiding the tedious handling of cut membranes.
• Preserve stem cells: It is imperative to use a triple antibiotic paste (MTAP) diluted to 1 mg/ml and a final irrigation with 17% EDTA to promote cell adhesion and the survival of periapical tissues.
• Standardize follow-up: The use of image analysis software (such as ImageJ) on your periapical radiographs allows for an objective millimetric measurement of dentinal wall thickening and root lengthening at 12 months.

Regenerative endodontic therapy (RET) has revolutionized the management of necrotic immature permanent teeth. While apical blood clot induction has long been the standard, the limited release of growth factors has pushed clinicians toward autologous platelet concentrates. This prospective observational study, conducted between 2023 and 2025, compares two regeneration vectors: injectable PRF (i-PRF) and classic PRF in membrane form.

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