МETHODS OF POST-POLYMERIZATION PROCESSING OF BASES IN REMOVABLE DENTURES IN ORDER TO REDUCE THE QUANTITY OF RESIDUAL MONOMER

Abstract

The purpose of this study was to assess the effect of post-polymerization treatment on the quantity of methyl methacrylate released into water from polymethyl methacrylate base samples of materials subjected to different procedures.
 Materials and methods. For each technique, 10 samples in the form of a square with a side of 50 mm and a thickness of 5.0 mm were made for the base materials VBPLP, ABPHT, BPHT in accordance with the manufacturers' instructions. Five different procedures for reducing the amount of residual monomer of polished base plastics samples were studied, namely: controlled vacuuming in water at 60-80°C for 10 minutes (A), immersion in an ethanol solution at a temperature of 55°C for 10 minutes (B), ultrasonic treatment at 40 kHz for 5 minutes in distilled water (C), immersion in distilled water for 24 hours (D), boiling in water for 3 hours (E), control samples without post-polymerization treatment (F).
 Following the implementation of procedures for minimizing residual monomer levels in the studied samples, they were placed in individual containers containing 10 ml of distilled water for 12 hours at a temperature of 37°C. The quantification of water-eluted MMA was conducted through liquid chromatography.
 Results. Of the 180 measurements performed, 42 showed values below the limit of detection (MW: 2.0 ppm), 58 below the lower limit of quantification (LMQ: 6.0 ppm), and 80 had average values between 6.4 and 13.2 ppm MMA. The NLQ is the lowest concentration of the analyte that differs from the blank, usually with a confidence level of 99%, while the MV is the lowest concentration of the analyte that can be reliably determined with repeatability and precision. The lower limit of quantification is 6.00 ppm, the detection limit is 2.00 ppm.
 Conclusions. The risk of residual monomer as a primary stimulus for a sensitizing reaction can be minimized by using these regimens. The results of measuring the amount of elution of the MMA monomer in water for two of the three materials tested were below the detection limit in both of these modes.