Effect of Nano forms of propolis and antibiotic pastes as canal medicaments on radicular dentin micro-hardness and chemical structure : (In vitro study).

Abstract

The aim of this study was to evaluate the effect of Propolis and Antibiotic Pastes (Double and Triple) in both Micro and Nano-forms on radicular dentin micro-hardness and chemical structure. Forty-two extracted human single rooted mandibular premolars were collected with mature apices and one root canal. Those teeth were deidentified and checked radiographically. The forty-two teeth were classified into three different experimental groups equally (14 each) according to the type of testing materials; group A (Propolis-PRP), group B (Double antibiotic paste- DAP) and group C (Triple antibiotic paste-TAP). Each group will be subdivided into two subgroups (7 each) according to the particle size used to prepare the medicament either Micro or Nano-sized. Subgroup A1 (Micro-PRP), subgroup A2 (Nano-PRP), subgroup B1 (Micro-DAP), subgroup B2 (Nano-DAP), subgroup C1 (Micro- TAP) and subgroup C2 (Nano-TAP). Teeth were decoronated to a standard 16 mm, an apical patency was checked using K-file #10 then 1mm was subtracted in order to establish an accurate working length. Mechanical preparation was done using Mpro three files rotary system with 3ml of 2.6% sodium hypochlorite irrigation with manual dynamic agitation subsequent to each filing step. Canals were rinsed with saline as a final flush and dried with paper point. The prepared samples were subjected to longitudinal sectioning resulting in buccal and lingual halves by an isomet. All buccal halves considered as the experimental half while lingual halves considered as the coronal half. Each half was mounted in acrylic resin for easy material application and machine testing. Each lumen was encircled by pink wax to preserve medicament in place. Each experimental group received precisely 1 ml of the assigned medicament for each subgroup. Then samples left untouched and stored for two weeks in 37C° and 100% humidity in incubator. After 14 days, 2.5% NaOCL irrigation using ultrasonic file # 15 for one minute with power 9 was used in order to remove and wash away the applied medicaments. Following that, the lumens were flushed thoroughly with 5ml distilled water. Samples were subjected to the Vickers micro-hardness and an Energy Dispersive Xray- Scanning Electron Microscope (EDX-SEM) test to check both the control and experimental group’s micro-hardness and chemical structure. Moreover, both control and experimental samples were fixed in the Vickers machine in a manner allowing the sample’s half to face upward toward the machine indenter. Three indentations have been done at coronal, middle and apical levels. The indenter was placed smoothly at 1 μm form the lumen, creating indentations at the edge towards the dentin outer border using 50 g load for 10 seconds. The indenters were measured using an optical microscope connected to a digital camera with image analysis software. After the load is removed, the indentation is focused with the magnifying eye piece and the two impression diagonals were measured, usually to the nearest 0.1- μm with a micrometer, and averaged. The final hardness values were obtained as the mean of each three indentation readings. Furthermore, the same specimens both control and experimental were subjected to a specific type of x-ray that would be detected by an EDX detector at the root parts that are devoid of previous indentations. The detector was placed in a very close angle to the sample’s half, detecting the generated photons of the x-ray; to predict the integrity of this sample. Afterwards; the halves were introduced into the scanning electron microscope that is already attached to EDX. Evaluation, analyzation and detection of any morphological and structural changes within the samples were made, at accelerating voltage 30 K.V magnification14x up to 1000000 and resolution for Gun.1nm. Upon comparing the outcomes, the results showed that the material and root canal level had a statistically significant effect on the median percentage change on root dentin micro-hardness. DAP as an intracanal medicament had the greatest effect regarding percentage reduction on dentin micro-hardness, followed by Nano-TAP. Also, with respect to root levels, there was no significant difference found at the coronal root level. However, DAP and Propolis had the highest statistically significant median percentage decrease in micro-hardness at the middle root level, while Nano-TAP had the highest statistically significant median % reduction in micro-hardness at apical root levels. Upon comparing chemical structure outcomes, the results showed that there was a statistically significant mean calcium weight % difference found between canal medicaments at different root levels. Control group had the highest statistically significant mean calcium weight %, whereas Propolis had the lowest statistically significant mean calcium weight % among the groups at different root levels. Additionally, the coronal root level had the highest statistically significant mean calcium weight % among middle and apical root levels. In addition, the results showed that there was a statistically significant mean phosphorus weight % difference found between canal medicaments at different root levels. Propolis group had the highest statistically significant mean phosphorus weight %, whereas control had the lowest statistically significant mean phosphorus weight % among the groups at different root levels. furthermore, no statistically significant difference was found between the middle and apical root levels; both had the highest statistically significant mean phosphorus weight % than coronal root level. Besides, the results showed that there was a statistically significant mean Ca:P ratio difference found between canal medicaments at different root levels. The control group had the highest statistically significant mean Ca:P ratio, whereas the Propolis group had the lowest statistically significant mean Ca:P ratio among the groups at different root levels. Also, the coronal root level had the highest statistically significant mean Ca:P ratio among middle and apical root levels. Finally, there was no statistically significant correlation between Ca, P weight %, Ca:P ratio and percentage decrease in microhardness.