Colour Doppler Ultrasonographic Evaluation of Vascular Healing Dynamics After Endodontic Surgery Using Platelet-Rich Fibrin and Chorion Membranes: A Randomized Controlled Trial

Technical Summary: Colour Doppler Ultrasonographic Evaluation of Vascular Healing Dynamics After Endodontic Surgery

Problem Statement
Apical periodontitis, an inflammatory disease driven by microbial infection, often necessitates endodontic surgery when non-surgical retreatment fails or is unfeasible. While contemporary surgical protocols aim to eliminate pathology and seal the root end, the predictability of healing in large defects remains variable. Current clinical evaluation relies heavily on conventional radiography, which effectively assesses mineralized tissue repair but fails to capture early vascular events critical to the healing process. Furthermore, while guided tissue regeneration using membranes (such as Platelet-Rich Fibrin or Chorion membranes) is proposed to support healing by preventing epithelial downgrowth and facilitating osteogenic repopulation, comparative clinical evidence regarding their efficacy in periapical surgery is often limited by small sample sizes, short follow-ups, and a lack of vascular assessment.

Methodology
This study was a parallel-group, three-arm randomized controlled trial (RCT) conducted at King George's Medical University, India.

• Participants: 48 patients (aged 18–40) requiring endodontic surgery for single-rooted anterior teeth with periapical lesions measuring 8–20 mm.
• Groups: Participants were randomly allocated (1:1:1) to three treatment groups, all receiving a standardized surgical protocol (debridement, root-end resection, ultrasonic preparation, and Mineral Trioxide Aggregate sealing):
  1. Control: Hydroxyapatite (HA) graft alone.
  2. Intervention A: HA graft + Platelet-Rich Fibrin (PRF) membrane.
  3. Intervention B: HA graft + Chorion membrane.
• Assessment Tools: The study utilized high-frequency linear probe ultrasonography and Colour Doppler imaging at baseline, 1 month, and 6 months post-surgery.
• Outcome Measures:
  • Primary: Reduction in lesion volume at 6 months.
  • Secondary: Reduction in lesion surface area and changes in Peak Systolic Velocity (PSV) as a quantitative indicator of vascular response.
• Analysis: Statistical analysis employed repeated-measures ANOVA for intragroup changes and one-way ANOVA for intergroup comparisons, with a significance level of p < 0.05.

Key Results

• Hard Tissue Healing: All three groups demonstrated statistically significant reductions in lesion surface area and volume over the 6-month period.
  • At 6 months, the Chorion membrane group showed the highest numerical mean percentage reduction in surface area (84.28%) and volume (93.90%), followed by the PRF group and the HA-only group.
  • However, intergroup differences in both surface area and volume reduction were not statistically significant (p = 0.164 for area; p = 0.058 for volume). Thus, no single method demonstrated superiority in hard-tissue healing outcomes.
• Vascular Response (Colour Doppler):
  • At 1 month, the Chorion group showed the highest mean PSV, though the difference was not statistically significant (p = 0.059).
  • At 6 months, a statistically significant intergroup difference in PSV was observed (p = 0.013). The Chorion membrane group exhibited a substantially higher peak systolic velocity (9.31 ± 6.02) compared to the other groups, suggesting a stronger vascular response during the healing phase.
• Safety: No intraoperative or postoperative adverse events were reported.

Key Contributions

1. Novel Imaging Modality: The study validates the use of Colour Doppler ultrasonography as a non-ionizing modality for monitoring periapical healing. It successfully quantified vascular dynamics (via PSV) that are invisible to conventional radiography.
2. Comparative Efficacy: It provides comparative data on HA grafts used alone versus those augmented with PRF or Chorion membranes in a controlled surgical setting, finding that while all supported healing, the Chorion membrane group exhibited the most robust vascular activity.
3. Differentiation of Outcomes: The research distinguishes between vascular healing (angiogenesis) and hard-tissue regeneration, noting that a superior vascular response (observed in the Chorion group) did not necessarily translate into statistically superior hard-tissue volume reduction within the 6-month timeframe.

Significance and Claims
The paper claims that while Platelet-Rich Fibrin and Chorion membranes are effective adjuncts that facilitate periapical healing when combined with hydroxyapatite, the Chorion membrane group demonstrated a distinct and statistically significant stronger vascular response at 6 months, as evidenced by higher Peak Systolic Velocity.

However, the authors maintain a modest stance regarding clinical superiority: the study did not establish that the Chorion membrane or PRF is superior to hydroxyapatite alone for hard-tissue healing (lesion volume/area reduction) within the 6-month follow-up. The primary clinical significance highlighted is the utility of Colour Doppler ultrasonography for early, non-ionizing monitoring of vascular healing dynamics, offering biological insights prior to the manifestation of hard-tissue changes. The authors conclude that membrane selection should consider factors such as availability, cost, and ease of use, as all three interventions supported successful healing.