An in-vitro comparative evaluation of quantitative release of transforming growth factor β-1 from dentin upon the action of endodontic irrigants, medicaments, ultrasonic activation, and low-level laser irradiation

Abstract

Aim: The aim of this article is to evaluate the amount of transforming growth factor beta-1 (TGF β-1) released from dentin upon the action of various endodontic irrigants, medicaments, ultrasonic activation, and low-level laser irradiation. Materials and Methods: To assess the effect of endodontic irrigants and medicaments on TGF β-1 release, 200 dentin disks of 1 µm thickness prepared from human mandibular premolars were divided into five groups of 40 each. The specimens in the test groups were treated with four reagents: Group A: (2% chlorhexidine gluconate); Group B: (2.5% sodium hypochlorite); Group C: [calcium hydroxide powder (Ca(OH)2)]; Group D: [triple antibiotic paste (TAP) (minocycline 100 mg + ciprofloxacin 200 mg + metronidazole 500 mg)]; and one control reagent group, i.e., Group E: (normal saline). Dentin disks were subsequently treated with 10% ethylenediaminetetraacetic acid (EDTA). To assess the effect of ultrasonic activation and low-level laser irradiation on TGF β-1 release, 90 dentin disks of 1 mm thickness obtained from mandibular premolar roots were divided into 6 groups of 15 disks each: Group 1: (10% EDTA +ultrasonic activation), Group 2: [10% citric acid (CA) + ultrasonic activation], Group 3: (10% EDTA + low-level laser), Group 4: (10% CA+ low-level laser), and two control groups, i.e., Group 5 (10% EDTA) and Group 6 (10% CA). Three subgroups were formed among main groups indicating the region from where the specimens were prepared, namely, coronal, middle, and apical thirds. The irrigation solutions from all the above groups were collected, frozen in liquid nitrogen, and stored at −80°C and later thawed and subjected to growth factor quantification by using an enzyme-linked immunosorbent assay test system for TGF β-1. Results: Root canal irrigant 2% chlorhexidine gluconate and intracanal medicament calcium hydroxide both showed an inducing effect on TGF β-1 release, giving a maximum value of 0.741 ng/mL. The least value of 0.0823 ng/mL was given by 2.5% sodium hypochlorite, showing its negative impact on growth factor release. TAP showed a neutral effect similar to that of the control group (normal saline), giving a value of 0.247 ng/mL. Ultrasonic activation and low-level laser irradiation of EDTA and CA have both improved TGF β-1 release from dentin. Conclusion: Chlorhexidine gluconate and calcium hydroxide exerted a positive influence on TGF β-1 release from dentin, whereas sodium hypochlorite retarded its release and TAP gave a neutral impact similar to normal saline. Ultrasonic activation and low-level laser irradiation can enhance TGF β-1 expression. There is no significant difference in the growth factor release among the different regions of root dentin.