Early Healing Events after Periodontal Surgery: Observations on Soft Tissue Healing, Microcirculation, and Wound Fluid Cytokine Levels

Abstract

Early wound healing after periodontal surgery with or without enamel matrix derivative/biphasic calcium phosphate (EMD/BCP) was characterized in terms of soft tissue closure, changes of microcirculation, and expression of pro- and anti-inflammatory cytokines in gingival crevicular fluid/wound fluid (GCF/WF). Periodontal surgery was carried out in 30 patients (18 patients: application of EMD/BCP for regeneration of bony defects; 12 patients: surgical crown lengthening (SCL)). Healthy sites were observed as untreated controls. GCF/WF samples were collected during two post-surgical weeks. Flap microcirculation was measured using laser Doppler flowmetry (LDF). Soft tissue healing was evaluated after two weeks. GCF/WF levels of interleukin 1β (IL-1β), tumour necrosis factor (TNF-α), IL-6, and IL-10 were determined using a multiplex immunoassay. Surgery caused similar reductions of flap microcirculation followed by recovery within two weeks in both EMD/BCP and SCL groups. GCF/WF and pro-inflammatory cytokine levels were immediately increased after surgery, and returned only partially to baseline levels within the two-week observation period. Levels of IL-10 were temporarily reduced in all surgical sites. Flap dehiscence caused prolonged elevated levels of GCF/WF, IL-1β, and TNF-α. These findings show that periodontal surgery triggers an immediate inflammatory reaction corresponding to the early inflammatory phase of wound healing, and these inflammation measures are temporary in case of maintained closure of the flap. However, flap dehiscence causes prolonged inflammatory exudation from the periodontal wound. If the biological pre-conditions for periodontal wound healing are considered important for the clinical outcome, care should be taken to maintain primary closure of the flap.

Keywords: cytokines; periodontal regeneration; periodontal surgery; surgical crown lengthening; wound healing.

Figure 1

(A) LDF measurements of microcirculation; (B) Measurements of GCF/WF volume; (C) Concentration of IL-1β in GCF/WF samples; and (D) Total amount of IL-1β in GCF/WF samples. EMD/BCP (enamel matrix derivative/biphasic calcium phosphate): red, SCL (surgical crown lengthening): blue, Ctrl (control): white; LDF: laser Doppler flowmetry; GCF/WF: gingival crevicular fluid/wound fluid; IL-1: Interleukin 1β; *: p < 0.05; **: p < 0.01, ***: p < 0.001.

Figure 2

(A) Concentration of TNF-α in GCF/WF samples; (B) Total amount of TNF-α in GCF/WF samples; (C) Concentration of IL-6 in GCF/WF samples; (D) Total amount of IL-6 in GCF/WF samples; (E) Concentration of IL-10 in GCF/WF samples. EMD/BCP (enamel matrix derivative/biphasic calcium phosphate): red, SCL (surgical crown lengthening): blue, Ctrl (control): white; GCF/WF: gingival crevicular fluid/wound fluid; TNF-α: Tumour necrosis factor α; IL-6: Interleukin 6; IL-10: Interleukin 10; *: p < 0.05; **: p < 0.01, ***: p < 0.001.

Figure 2

(A) Concentration of TNF-α in GCF/WF samples; (B) Total amount of TNF-α in GCF/WF samples; (C) Concentration of IL-6 in GCF/WF samples; (D) Total amount of IL-6 in GCF/WF samples; (E) Concentration of IL-10 in GCF/WF samples. EMD/BCP (enamel matrix derivative/biphasic calcium phosphate): red, SCL (surgical crown lengthening): blue, Ctrl (control): white; GCF/WF: gingival crevicular fluid/wound fluid; TNF-α: Tumour necrosis factor α; IL-6: Interleukin 6; IL-10: Interleukin 10; *: p < 0.05; **: p < 0.01, ***: p < 0.001.

Figure 3

Soft tissue healing two weeks after surgery (EMD/BCP group): (A) EHI 1 and closed flap; (B) EHI 5 and flap dehiscence. EMD/BCP: enamel matrix derivative/biphasic calcium phosphate; EHI: early healing index.

Figure 4

GCF/WF and cytokine levels in sites with/without dehiscence (pooled results for all sites/both groups): (A) Significantly higher GCF/WF volume were found in sites with flap dehiscence, when compared to closed flaps (*: p < 0.05); (B) Significantly higher total amounts/sample of IL-1β and TNF-α were found in sites with flap dehiscence, when compared to closed flaps (*: p < 0.05). Dehiscence: grey, closed flap: green.

Figure 5

Pre- and post-surgical radiographs (EMD/BCP group). (A) Deep vertical infra-bony defect is visible on the mesial aspect of tooth 27; (B) The bone defect is filled with radio-opaque bone substitute (BCP) beyond the residual contour of the alveolar crest.