Flowable resin composite versus cyanoacrylate tissue adhesive for palatal donor site protection after free gingival graft harvesting: a split-mouth randomized controlled clinical trial

Technical Summary: Flowable Resin Composite versus Cyanoacrylate Tissue Adhesive for Palatal Donor Site Protection

Problem Statement
The free gingival graft (FGG) remains the gold standard for increasing keratinized tissue in periodontal plastic surgery. However, the harvesting of FGGs from the palatal donor site necessitates healing by secondary intention, a process frequently associated with significant postoperative pain, discomfort, and reduced patient acceptability. While various interventions—including sutures, collagen sponges, platelet-rich fibrin, and mechanical barriers like periodontal dressings and palatal stents—have been investigated to mitigate morbidity, cyanoacrylate tissue adhesive (CTA) has emerged as a common option for wound protection. Despite its efficacy in hemostasis and reduced surgical time, CTA presents limitations, including the potential for creating a rough surface that causes patient discomfort, susceptibility to premature detachment due to bleeding or mechanical displacement, and higher material costs. Conversely, flowable resin composite (FRC) has been suggested as a mechanical barrier with favorable outcomes in reducing pain and promoting healing, yet evidence from split-mouth models comparing these two specific modalities remains limited.

Methodology
This study employed a randomized, controlled, split-mouth clinical trial with a double-blind protocol involving both patients and examiners. The study population consisted of 15 patients (mean age 45.1 years) recruited from the Dental Polyclinic of the Military Fire Brigade of the Federal District, Brazil, who required root coverage procedures using de-epithelialized free gingival grafts (d-FGG).

• Experimental Design: Each patient underwent two separate surgical sessions, separated by a minimum 6-week washout interval, to harvest grafts from both palatal sides. This design ensured that one palatal wound was protected with CTA (control) and the contralateral side with FRC (experimental), with randomization determining the side and treatment sequence.
• Surgical Protocol: Following graft harvesting using the Zucchelli technique, all palatal wounds were sealed with a porcine-derived absorbable hemostatic collagen sponge stabilized by cross-linked loop sutures.
  • FRC Application: The test side received a layer of flowable resin composite applied over the sponge and the adjacent teeth (conditioned with 37% phosphoric acid and dentin adhesive), then light-cured to create a smooth, homogeneous barrier.
  • CTA Application: The control side received drops of cyanoacrylate tissue adhesive applied along the wound margins and over the sponge.
• Data Collection: Primary outcomes included postoperative pain perception measured via Visual Analog Scale (VAS) on days 1–7, 10, and 14, and analgesic consumption (dipyrone 500 mg). Secondary outcomes included patient comfort, preference for treatment repetition, and wound healing assessed through photographic analysis of color, texture, and contour by blinded examiners on days 7, 14, 21, and 30.
• Statistical Analysis: Comparisons were performed using paired t-tests for continuous variables and non-parametric Wilcoxon and Friedman tests for pain scores and healing parameters. Inter-examiner reproducibility was confirmed with a Kappa index >0.8.

Key Contributions and Results
The study provides comparative data on the clinical performance of FRC versus CTA in a split-mouth setting, minimizing inter-individual variability.

• Pain Management: Patients reported significantly lower pain scores on the FRC side compared to the CTA side on postoperative days 5, 6, and 7 (p<0.05). No statistically significant differences were observed on days 1–4, 10, or 14. The maximum pain score on the FRC side ranged from 3 to 5 during the critical period, whereas the CTA side reached a maximum of 8.
• Analgesic Consumption: While not statistically significant (p=0.0519), a trend toward lower analgesic consumption was observed with FRC (mean 2.5 ± 3.9 tablets) compared to CTA (mean 5.5 ± 6.4 tablets).
• Patient Comfort and Preference: A significant majority (80%) of patients reported greater comfort with the FRC protection (p=0.0022). Furthermore, 100% of patients indicated they would undergo the FRC treatment again, compared to only 46.7% for the CTA treatment.
• Material Stability and Integrity: No instances of total or partial disintegration were reported for the FRC barrier. In contrast, 5 patients (33% of the sample) experienced total or partial disintegration of the CTA protection before day 7.
• Wound Healing: Photographic analysis of color, texture, and contour revealed no significant differences between the FRC and CTA sides at any time point (p>0.05). Both groups demonstrated similar healing patterns, with a temporary increase in healing scores upon barrier removal at day 7, followed by improvement by day 21.
• Economic Factor: The study noted that the material cost for FRC was 60% lower than that of CTA for covering the same number of wounds.

Significance and Claims
The paper concludes that FRC offers clinical efficacy comparable to CTA regarding wound healing and analgesic consumption but provides superior pain relief during the critical postoperative window of days 5 through 7. The authors attribute the enhanced pain control and patient comfort to the superior retention and stability of the FRC barrier, which remained intact over the surgical wound for the entire first week, unlike CTA which showed premature detachment in a subset of patients.

The study posits that FRC serves as an effective mechanical barrier that creates a smooth surface, reducing tongue irritation and maintaining a stable environment for healing. Additionally, the authors highlight the economic advantage of FRC, noting its lower cost and the fact that it utilizes materials routinely available in dental offices. The paper asserts that FRC may represent a practical and preferred alternative for palatal donor site protection following free gingival graft harvesting, particularly for improving patient experience in the first week post-surgery. The authors maintain a modest tone, acknowledging limitations such as the sample size and the need for future studies involving larger cohorts, histological analysis, and comparisons with other protective materials.