International Journal of Chemical and Biochemical Sciences (ISSN 2226-9614)[/vc_column_text][/vc_column][/vc_row]

VOLUME 25(19) (2024)

Evaluation of effect of different curing protocols on polymerization shrinkage stress of various bulk fill composites-An in vitro study

¹Ravina Parmar, ²Geeta Asthana, ^3*Dhwani Morakhia

¹Government Dental College and Hospital, Ahmedabad, Gujarat, India

²Government Dental College and Hospital, Ahmedabad, Gujarat, India

³Government Dental College and Hospital, Ahmedabad, Gujarat, India

Abstract

The current study is aimed to evaluate the effect of three different curing protocols i.e. conventional curing, soft start and pulse delay curing on shrinkage stress of various bulk fill composites. Three bulk-fill resin composites (Tetric N-Ceram bulk-fill, Xtra fill, and Filtek Bulkfill) with the sample size of 108 were compared for polymerization shrinkage stress. Curing methods used were 1) conventional, 2) soft-start curing and 3) Pulse delay. 36 disk-shaped specimens of each composite with a dimension of 1 mm thickness, 4 mm breadth and 10mm length were fabricated. Universal testing machine (UTM) with a speed of 1mm/min was used to measure the shrinkage stress generated during polymerization by load cell (50 kg) attachment. Movement of load cell was continuously monitored and recorded using software (blue hill) Data was recorded as force (in Newton)* Time (in seconds) and converted to MPa by dividing the force  by the areas of transverse section of specimens (4 mm²). Data was analysed using SPSS version 23. Friedman’s test for intra-group comparison and one-way ANOVA with post hoc tukey test for intergroup comparison. Statistically significant difference was present in PSS of all three composites with highest PSS when cured with conventional curing method, lesser with soft start and least in pulse delay curing method. Irrespective of the bulk fill composites used the soft start and pulse delay curing protocols cause less PSS and seems to be promising curing methods. Less PSS will lead to less stress at tooth-restoration interface and probably prevent debonding.

Keywords: Bulk-fill composite, Polymerization shrinkage stress, Pulse delay curing, soft start curing, Universal Testing machine.

Full length article – PDF   *Corresponding Author, e-mail: dhwanimorakhia7021@gmail.com               Doi # https://doi.org/10.62877/97-IJCBS-24-25-19-97