In vitro evaluation of nanohydroxyapatite synthesized from eggshell waste in occluding dentin tubules

Abstract

Objectives: Dentin hypersensitivity (DH) is a notable painful condition with a negative impact on quality of life. This paper evaluates the occluding abilities of nanohydroxyapatite synthesized from the eggshell waste (EnHAp) in the treatment of DH. Methods: EnHAp was synthesized following the wet chemical precipitation method. The purity and phase change were characterized using Fourier transform infrared (FTIR) and X-ray diffraction (XRD). Field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) were used to observe the morphology of EnHAp. The occluding capabilities were evaluated in vitro using the bovine model. Twenty-five simulated dentin specimens were randomly assigned to five groups: Group 1, untreated; Group 2, eggshell powder alone; Group 3, calcined eggshell powder; Group 4, Colgate Sensitive treated, EnHAp; and Group 5, calcium dihydrogen phosphate (n = 5). The specimens were then subjected to remineralization protocol. The tubule occluding capabilities were observed using FESEM. Analysis of variance was used to analyze the occluding ratio values for all treated specimens. Post hoc test with Bonferroni correction was used to identify the mean differences among the five test groups (α = .05). Results: The FTIR and XRD results confirm that synthesis of EnHAp occurred. HRTEM and FESEM revealed an irregular rod structure with a particle size of 65 nm. The occluding area ratios observed for the EnHAp specimens were significantly higher than other test groups (p < 0.001). Conclusions: The application of EnHAp resulted in an efficient occlusion of dentin tubule. This study suggests that EnHAp is an effective therapy to treat DH.

An investigation in the remineralization and acid resistant characteristics of nanohydroxyapatite produced from eggshell waste via mechanochemistry

“…12 An irregular-red like structure with a slightly higher particle size of 80 to 100 nm, were, however, observed in another study. 20 The difference in the morphology observed in both studies may be attributed to the preparation technique.…”

“…This may likely be attributed to the solubility of the calcined eggshell in the deionized water, and or the absence phosphate group. 20 On the contrary, the samples treated with nHAp shows complete remineralization of the dentine tubules (Figure 7(e)). This is in agreement with several randomized clinical trials that confirmed the remineralization characteristics of nHAp.…”

“…For instance, the absorption band observed around ~1000 cm −1 is attributed to the P–O asymmetrical stretching of a PO 4 3− group. 15,20 The hydroxyl O–H bending identified by the broad band around ~3450 and 3000 cm −1 and sharp band at 1600 cm −1 was attributed to water molecules, 15,20 and the sharp band around 3750 cm −1 is attributed to the OH stretching. 12 In addition, the bands at 1450 cm −1 suggest that the presence of the CO 3 2− ions in the structure of the produced nHAp.…”

“…Moreover, the crystalline peak observed at 35° correlates to the calcium carbonate calcite phase. 20 Overall, the synthesized nHAp has a crystallinity value of 82.19%. The peak area was determined from the Gaussian plot and the crystallinity calculated using the formula below.…”

“…The tooth enamel was placed in a 4% citric acid solution containing each of the respective powders for 2 min and thereafter rinsed with deionized water and blot dried. For the remineralization test, the dentine specimens used were prepared according to Onwubu et al, 20 and then assigned randomly into a group of five ( n = 5). Using 1 g of the sample powder and 40 mL deionized water at a time interval of 5 min, the specimens were agitated following the protocol described by Onwubu et al 20 The image of the specimens before and after treatment and exposure were studied using SEM.…”