Assessment of dimensional stability of novel VPES impression material at different time intervals with standard disinfectants

Abstract

Background: Vinyl polyether silicone (VPES) is a novel impression biomaterial made of a combination of vinyl polysiloxane (VPS) and polyether (PE). Thus, it is significant to assess its properties and behaviour under varied disinfectant test conditions. This study aimed to assess the dimensional stability of novel VPES impression material after immersion in standard disinfectants for different time intervals.

Methods: Elastomeric impression material used -medium body regular set (Monophase) [Exa'lence GC America]. A total of 84 Specimens were fabricated using stainless steel die and ring (ADA specification 19). These samples were distributed into a control group (n=12) and a test group (n=72). The test group was divided into 3 groups, based on the type of disinfectant used - Group-A- 2% Glutaraldehyde, Group-B- 0. 5% Sodium hypochlorite and Group-C- 2% Chlorhexidine each test group was further divided into 2 subgroups (n=12/subgroup) based on time intervals for which each sample was immersed in the disinfectants - subgroup-1- 10 mins and Subgroup 2- 30 mins. After the impression material was set, it was removed from the ring and then it was washed in water for 15 seconds. Control group measurements were made immediately on a stereomicroscope and other samples were immersed in the three disinfection solutions for 10 mins and 30 mins to check the dimensional stability by measuring the distance between the lines generated by the stainless steel die on the samples using a stereomicroscope at x40 magnification.

Results: The distance measured in the control group was 4397.2078 µm and 4396.1571 µm; for the test group Group-A- 2% Glutaraldehyde was 4396.4075 µm and 4394.5992 µm; Group-B- 0. 5% Sodium hypochlorite was 4394.5453 µm and 4389.4711 µm Group-C- 2% Chlorhexidine was 4395.2953 µm and 4387.1703 µm respectively for 10 mins and 30 mins. Percentage dimensional change was in the range of 0.02 - 0.25 for all the groups for 10 mins and 30 mins.

Conclusions: 2 % Glutaraldehyde is the most suitable disinfectant for VPES elastomeric impression material in terms of dimensional stability and shows minimum dimensional changes as compared to that of 2% Chlorhexidine and 0.5% Sodium hypochlorite.

Keywords: Biomaterials; Biotechnology; Dental materials; Glutaraldehyde; In-vitro study; Novel materials; Sodium hypochlorite; Vinyl polyether silicone (VPES).

Fig. 1

Flow chart of the study

Fig. 2

a-Stainless steel (SS) metal master die (MMD) showing the horizontal X,Y,Z lines, V1, V2 vertical lines and C , D points; b corresponding ring of metal master die (MMD) ; c Representative VPES impression disc showing C’ , D’ point corresponding to C and D on metal master die (MMD).

Fig. 3

Procedural steps for making samples-a Armamentarium for the recording of the impression of metal die; b Dispensing of impression material using automixing gun; c Glass-plate is placed on top of the metal die; d VPES impression samples are kept in a tray for washing under running water

Fig. 4

Impression samples immersed in three disinfectant solutions in beakers

Fig. 5

a Report showing micro-measurement between the points C-D on Metal die; b Report showing micro-measurement between the points C’-D’ on impression disc (Control group)

Fig. 6

Mean dimensional change of line C’D’

Fig. 7

Mean Percentage dimensional change