Objectives This study aimed to evaluate and compare the effects of four gingival retraction techniques—retraction cord with astringent (RCA), Expasyl paste (EXP), Magic FoamCord (MF), and diode laser troughing (LT)—on gingival displacement and periodontal health in digital impression workflows, specifically investigating whether the type of retraction method significantly influences horizontal and vertical tissue displacement, sulcus depth, and gingival height loss (GHL). Methods Thirty-two participants requiring full-coverage restorations on maxillary premolars were randomly assigned to four groups (n=8 per group). Gingival displacement was measured using pre- and post-retraction digital scans with an intraoral scanner. Horizontal and vertical displacement, sulcus depth, and GHL at 7, 15, and 30 days were recorded. Threshold analyses were performed to identify displacement values associated with increased GHL. Statistical analyses included one-way ANOVA, two-way repeated-measures ANOVA, and Pearson correlation (α = 0.05). Results RCA produced the greatest horizontal (0.72±0.08 mm) and vertical (0.68±0.07 mm) displacement and sulcus depth (0.75±0.09 mm), but also the highest GHL over time (0.28±0.04 mm at day 7; 0.10±0.02 mm at day 30). EXP demonstrated lower displacement values (horizontal: 0.48±0.03 mm; vertical: 0.42±0.04 mm) and the lowest GHL across follow-up periods. MF and LT yielded intermediate results. Nonlinear threshold behavior was observed: GHL increased sharply beyond ~0.55 mm horizontal and ~0.60 mm vertical displacement. Conclusions Expasyl paste provides sufficient gingival displacement for digital impressions while minimizing tissue trauma, whereas retraction cords maximize sulcular widening at the cost of gingival health. Magic FoamCord and laser troughing are intermediate alternatives. Identifying horizontal and vertical displacement thresholds can guide clinicians in balancing effective retraction with periodontal preservation. Clinical relevance Optimal gingival retraction is essential for accurate digital impressions. Expasyl and similar atraumatic systems may improve patient outcomes by providing adequate margin exposure while preserving periodontal integrity, informing contemporary digital prosthodontic workflows.

Impact of four gingival retraction techniques on gingival tissue displacement and sulcus depth during digital impression procedures

期刊论文
发表日期：

2026年1月14日

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Merve Benli

摘要

Objectives

This study aimed to evaluate and compare the effects of four gingival retraction techniques—retraction cord with astringent (RCA), Expasyl paste (EXP), Magic FoamCord (MF), and diode laser troughing (LT)—on gingival displacement and periodontal health in digital impression workflows, specifically investigating whether the type of retraction method significantly influences horizontal and vertical tissue displacement, sulcus depth, and gingival height loss (GHL).

Methods

Thirty-two participants requiring full-coverage restorations on maxillary premolars were randomly assigned to four groups (n=8 per group). Gingival displacement was measured using pre- and post-retraction digital scans with an intraoral scanner. Horizontal and vertical displacement, sulcus depth, and GHL at 7, 15, and 30 days were recorded. Threshold analyses were performed to identify displacement values associated with increased GHL. Statistical analyses included one-way ANOVA, two-way repeated-measures ANOVA, and Pearson correlation (α = 0.05).

Results

RCA produced the greatest horizontal (0.72±0.08 mm) and vertical (0.68±0.07 mm) displacement and sulcus depth (0.75±0.09 mm), but also the highest GHL over time (0.28±0.04 mm at day 7; 0.10±0.02 mm at day 30). EXP demonstrated lower displacement values (horizontal: 0.48±0.03 mm; vertical: 0.42±0.04 mm) and the lowest GHL across follow-up periods. MF and LT yielded intermediate results. Nonlinear threshold behavior was observed: GHL increased sharply beyond ~0.55 mm horizontal and ~0.60 mm vertical displacement.

Conclusions

Expasyl paste provides sufficient gingival displacement for digital impressions while minimizing tissue trauma, whereas retraction cords maximize sulcular widening at the cost of gingival health. Magic FoamCord and laser troughing are intermediate alternatives. Identifying horizontal and vertical displacement thresholds can guide clinicians in balancing effective retraction with periodontal preservation.

Clinical relevance

Optimal gingival retraction is essential for accurate digital impressions. Expasyl and similar atraumatic systems may improve patient outcomes by providing adequate margin exposure while preserving periodontal integrity, informing contemporary digital prosthodontic workflows.