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.
Subject(s)
Dental Impression Materials , Glutaral , Materials Testing , Polyvinyls , Siloxanes , Dental Impression Materials/chemistry , Polyvinyls/chemistry , Siloxanes/chemistry , Time Factors , Glutaral/chemistry , Dental Disinfectants/chemistry , Sodium Hypochlorite/chemistry , Disinfectants/chemistry , Chlorhexidine/chemistry , Surface Properties , HumansABSTRACT
CONTEXT: Relining with heat cure denture base resin is time-consuming and the patient has to remain without dentures within this period. Recently, some autopolymerizing resins marketed as hard chairside reline systems with low exothermic heat allow the dentists to reline prosthesis directly in the mouth. However, the decision to use these materials must be based on physical properties such as dimensional accuracy that directly influences the accuracy of fit of the denture base. AIM: The aim was to compare the linear dimensional changes of two hard chairside reline resins with two laboratory heat cure resins at 3 times intervals after processing. SETTINGS AND DESIGN: A stainless steel split mold (International Organization for Standardization 1567) was used for sample fabrication. Five measurements of the reference dimensions (AB and CD) were measured directly from the mold and the samples with a profile projector, and mean difference were calculated. SUBJECTS AND METHODS: Forty samples were fabricated by incorporating the split mold into first pour of denture flasks and packing each of the chairside reline resins ("Kooliner" and "Ufi Gel Hard") and laboratory heat cure resins ("Dental Products of India Heat Cure" and "Trevalon"). The mean difference in dimensional change at 3 times intervals (0 h, 4 days and 2 months) were calculated and subjected to statistical analysis. STATISTICAL ANALYSIS USED: One-way ANOVA, RMANOVA and post hoc Tukey's tests. RESULTS: All resins showed different levels of significant shrinkage (P<0.001) after processing (T0) ranging from -0.128 to -0.310 mm. After 4 days (T1), there was significant shrinkage (P<0.001) ranging from -0.168 to -0.296 mm. After 2 months (T2), there was again significant shrinkage (P<0.001) ranging from -0.018 to -0.216 mm. Chairside reline resins showed less dimensional shrinkage at each time interval than the laboratory heat cure resins. CONCLUSIONS: Hard chairside resins are dimensionally accurate than the laboratory heat cure resins.
