Sulcus reproduction with elastomeric impression materials: A new in vitro testing method

Objectives Aim of this study was to investigate the depth reproduction of differently wide sulci with elastomeric impression materials by single- and double-mix techniques using a tooth and sulcus model, simulating clinical conditions. Methods Impressions with one vinyl polysiloxane (VPS; FLE), two polyethers (PE; IMP and P2), and one hybrid VPS/PE elastomer (FUS) were taken from a truncated steel cone with a circumferential 2 mm deep sulcus, 50, 100 or 200 μm wide. The “root surface” was in steel and the “periodontal tissue” in reversible hydrocolloid. Single-mix impressions were taken with light-body (L) or monophase (M) pastes, double-mix impressions with L as syringe and M or heavy-body (H) as tray materials (n = 8). Sulcus reproduction was determined by 3D laser topography of impressions at eight locations, 45° apart. Statistical data analysis by ANOVA and multiple comparison tests (p < 0.05). Results For 200 μm wide sulci, significant differences were found between impression materials only: FLE = IMP > FUS = P2. At 50 and 100 μm width, significant differences were found between materials (IMP > FUS = FLE > P2) and techniques (L + H = L + M > M > L). Significance The sulcus model is considered useful for screening evaluation of elastomeric impression materials ability to reproduce narrow sulci. All tested materials and techniques reproduced 200 μm wide sulci to almost nominal depth. Irrespective of the impression technique used, IMP showed the best penetration ability in 50 and 100 μm sulci. Double-mix techniques are more suitable to reproduce narrow sulci than single-mix techniques.