Evaluation of different sterilization and disinfection methods on commercially made preformed crowns

Abstract

The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM). Preformed crowns (NuSmile Primary Anterior Crown (NSC), Kinder Krowns (KK), Pedo Pearls (PP) and polycarbonate crowns (PC)) were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group); steam autoclaving at 134 degrees C (30 psi) for 4 min (G2); steam autoclaving at 134 degrees C (30 psi) for 12 min (G3); steam autoclaving at 121 degrees C (15 psi) for 30 min (G4); and ultrasonication in a bath containing 4% Lysetol AF for 5 min at room temperature (chemical disinfection) (G5). Scanning electron micrographs of the crowns were taken before and after their sterilization or disinfection. The changes on the vestibular surface were then scored for the presence or absence of crazing, contour alteration, fracturing, and vestibular surface changes. The data were analyzed statistically using the chi-square test. No changes were observed before and after sterilization or disinfection in the stereomicroscopic evaluation of the vestibular surface of the crowns. However, all methods in which steam autoclaving was used to sterilize the crowns caused significant (P < 0.05) crazing and contour alterations of the vestibular surface of the crowns when they were examined by SEM. Chemical disinfection using an aldehyde-free disinfectant is the preferred method of disinfection for crowns that have been used previously in other dental patients.

Review on Preformed Crowns in Pediatric Dentistry—The Composition and Application

“…If necessary, they can be covered with composite [ 62 ]. Their disadvantages are their soft structure and possible shorter durability [ 63 ].…”

Anterior Crowns in Pediatric Dentistry: A Review

“…However, the coating tends to chip off in areas of heavy occlusion and in bruxers that can be easily repaired with composite. 2,4,6,10,19…”

“…Chemical disinfection or cold sterilization using an aldehyde-free disinfectant in an ultrasonic bath. 19,20,32 Preferred method for PVSSC, High density polyethylene veneered crowns, Polycarbonate crowns, Pedo Pearls and Pedo jacket crowns 2. Steam Autoclave SSCs, Zirconia crowns, Figaro crowns…”

Estudio y diseño de materiales de impresión 3d que soporten los sistemas de esterilización médicos

“…Debido a que en los dos procesos de esterilización por calor húmedo (121°C) y calor seco (140°C), se superan las temperaturas de transición vítrea y aumenta su CTE, existe la posibilidad de que las dimensionen del material se mantengan modificadas después del proceso de enfriado, ya que físicamente no se encontraron cambios dimensionales en las probetas luego de los procesos de esterilización. En otros estudios sobre policarbonato esterilizado a diferentes temperaturas, sobre 121°C por calor húmedo para coronas dentales estéticas, no se observaron cambios superficiales al realizar la revisión por estereomicroscopio a 60X, pero a través de micrografías por SEM se ha observado grietas y alteración del contorno de las coronas, estas grietas se produjeron por la presencia de las microfibras de vidrio en el compuesto y debido a que la esterilización se llevó a cabo a 134°C, siendo el punto de distorsión por calor de las coronas de 132.2°C, también se observaron cambios superficiales con la esterilización por calor húmedo a 121°C, similar a esta investigación, pero con un tiempo de exposición de 30 minutos [436].…”