Analysis of Ionic-Exchange of Selected Elements between Novel Nano-Hydroxyapatite-Silica Added Glass Ionomer Cement and Natural Teeth.

One of the foremost missions in restorative dentistry is to discover a suitable material that can substitute lost and damaged tooth structure. To this date, most of the restorative materials utilized in dentistry are bio-inert. It is predicted that the addition of nano-HA-SiO2 to GIC matrix could produce a material with better ion-exchange between the restorative material and natural teeth. Therefore, the aim of the current study was to synthesize and investigate the transfer of specific elements (calcium, phosphorus, fluoride, silica, strontium, and alumina) between nano-hydroxyapatite-silica added GIC (nano-HA-SiO2-GIC) and human enamel and dentine. The novel nano-hydroxyapatite-silica (nano-HA-SiO2) was synthesized using one-pot sol-gel method and added to cGIC. Semi-quantitative energy dispersive X-ray (EDX) analysis was carried out to determine the elemental distribution of fluorine, silicon, phosphorus, calcium, strontium, and aluminum. Semi-quantitative energy dispersive X-ray (EDX) analysis was performed by collecting line-scans and dot-scans. The results of the current study seem to confirm the ionic exchange between nano-HA-SiO2-GIC and natural teeth, leading to the conclusion that increased remineralization may be possible with nano-HA-SiO2-GIC as compared to cGIC (Fuji IX).

Surface morphological and mechanical properties of zinc oxide eugenol using different types of ZnO nanopowder.

Zinc oxide eugenol (ZOE) cements are generally made up of 80%-90% ZnO powder while the remaining content consists of eugenol bonding resin. ZnO structure plays a major role in the morphology and mechanical properties of ZOE. In this study, we investigated the effects of different particle sizes/shapes of ZnO particles on the surface and mechanical properties of ZOE. Three samples were prepared namely ZnO-Ax, ZnO-B and ZnO-K. The crystallite sizes calculated from XRD were 37.76 nm (ZnO-Ax), 39.46 nm (ZnO-B) and 42.20 nm (ZnO-K) while the average particle sizes obtained by DLS were 21.11nm (ZnO-Ax), 56.73 nm (ZnO-B) and 2012 nm (ZnO-K). Results revealed that the compressive strengths of ZOE-Ax and ZOE-B were improved by 87.92% and 57.16%, respectively, relative to that of commercial ZOE-K. Vickers hardness test demonstrated that the hardness of ZOE-Ax and ZOE-B also increased by 74.9% and 31.1%, respectively. The ZnO-Ax nanostructure possessed a small average particle size (21.11 nm), a homogeneous size distribution (DLS) and an oxygen-rich surface (from EDS and elemental mapping). Meanwhile, ZnO-B exhibited a slightly larger average particle size of 56.73 nm compared with that of other samples. Sample ZnO-Ax demonstrated the highest compressive strength which was attributed to its large particle surface area (21.11 nm particle size) that provided a large contact area and greater interfacial (or interlock) bonding capability if compared to that of ZnO-K sample (2012 nm particle size).

Cone-beam computed tomography analysis on root and canal morphology of mandibular first permanent molar among multiracial population in East Coast Malaysian population.

OBJECTIVE: The aim of this study is to investigate the variations in the number of root and canal in the mandibular first permanent molars (MFPMs) teeth in East Coast Malaysian population using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT images which show MFPMs recorded in HUSM Dental Clinic between January 2015 and June 2016 was obtained and analyzed for their number of roots and canals. A total of 208 CBCT images of MFPMs were collected; 118 patients had unilateral molars and 90 patients had bilateral molars. The following observations were made: (1) root number; (2) number of canals per root; and (3) comparisons of number of roots and canals according to gender, ethnicity, and position. RESULTS: The majority of cases of bilateral MFPM had the same number of roots (95.6%, 95% confidence interval [CI]: 89.01%, 98.78%) on both the right and left side and only 4 cases (4.4%, 95% CI: 1.22%, 10.99%) had 3 roots on the right and 2 roots on the left sides. The majority of cases had the same number of canals on both sides (66.7%, 95% CI: 55.95, 76.26%) and 33.3% (95% CI: 23.74%, 44.05%) with unequal number of canals. The occurrence of the number of canals was not independent of the sides of the arch (P < 0.001) and there was statistically significantly greater proportion of cases who had greater number of canals on the right side than the left (P = 0.03). The prevalence of right single-rooted MFPM was very small at 0.3% (n = 1) in a Malay male (95% CI: 0.00, 1.83) and the most prevalent was two roots first molar (88.4%). The number of roots was not associated with sex or ethnic group (P > 0.05). The MFPM with a single root was found to have only one mesial canal. For two rooted MFPM, the most prevalent occurrence was two canals at the mesial and one canal at the distal roots (59%); followed by single canals in each mesial and distal (21%) and double canals per root (18%). Three roots MFPM have either single or double canals in the mesial root and double canals in the distal root. CONCLUSIONS: The majority of population in the East Coast region of Malaysia has two roots and three root canals in their MFPMs. There was no difference in the number of roots between gender and ethnic and canals between ethnic.

In-vitro efficacy of different morphology zinc oxide nanopowders on Streptococcus sobrinus and Streptococcus mutans.

ZnO with two different morphologies were used to study the inhibition of Streptococcus sobrinus and Streptococcus mutans which are closely associated with tooth cavity. Rod-like shaped ZnO-A and plate-like shaped ZnO-B were produced using a zinc boiling furnace. The nanopowders were characterized using energy filtered transmission electron microscopy (EFTEM), X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, Raman spectroscopy and dynamic light scattering (DLS) to confirm the properties of the ZnO polycrystalline wurtzite structures. XRD results show that the calculated crystallite sizes of ZnO-A and ZnO-B were 36.6 and 39.4nm, respectively, whereas DLS revealed particle size distributions of 21.82nm (ZnO-A) and 52.21nm (ZnO-B). PL spectra showed ion vacancy defects related to green and red luminescence for both ZnO particles. These defects evolved during the generation of reactive oxygen species which contributed to the antibacterial activity. Antibacterial activity was investigated using microdilution technique towards S. sobrinus and S. mutans at different nanopowder concentrations. Results showed that ZnO-A exhibited higher inhibition on both bacteria compared with ZnO-B. Moreover, S. mutans was more sensitive compared with S. sobrinus because of its higher inhibition rate.

3D Surface Profile and Color Stability of Tooth Colored Filling Materials after Bleaching.

This study aims to evaluate the effects of vital tooth bleaching with carbamide peroxide home bleaching and in-office bleaching on the color stability and 3D surface profile of dental restorative filling materials. Thirty discs (n = 30) measure 6 mm in diameter and 2 mm thick for each of three restorative materials. These are nanofilled composite Filtek Z350 XT, the submicron composite Estelite Σ Quick, and nanofilled glass ionomer Ketac N100 nanoionomer and were fabricated in shade A2. Each group was further divided into three subgroups (n = 10): subgroup A (Opalescence PF), subgroup B (Opalescence Boost in-office bleaching), and subgroup C (distilled water) serving as control. Samples were bleached according to the manufacturer's instructions for a period of two weeks. The Commission Internationale de L'Eclairage (CIE L(*), a(*), b(*)) system was chosen for image processing, while 3D surface profile was tested with atomic force microscopy (AFM). Statistical analyses were performed with the Mann-Whitney tests and Krusal-Wallis with a P value of ≤ 0.05. The three restorative materials showed significant color changes (ΔE); P ≤ 0.05. In diminishing order, the mean color changes recorded were Estelite Σ (3.82 ± 1.6) > Ketac Nano (2.97 ± 1.2) > Filtek Z350 XT (2.25 ± 1.0). However, none of the tested materials showed statistically significant changes in surface roughness; P > 0.05.

Fracture resistance of over-flared root canals filled with MTA and resin-based material: an in vitro study

Aim: To measure the fracture resistance of over-flared roots filled with a variety of materials (gutta-percha-nano HA, resilon-epiphany, composite and mineral trioxide aggregate - MTA) using the Instron machine test and micro-computed tomography (Micro CT) Scan. In addition, scanning electron microscopy (SEM) images were used to illustrate the type of fracture patternsof the specimens. Methods: One hundred and twenty extracted human mandibular single rooted premolars were selected. A total of 105 out of the selected teeth were prepared to the working length and over-flared, leaving the apical 5 mm undisturbed. Fifteen samples had no treatment and were used as a positive control group (Group +ve). The 105 test teeth were further divided into 7 groups of 15 samples each. One of the 7 groups was designated as negative control (Group -ve) where teeth were over prepared and left without obturation.Remaining groups were filled with gutta-percha-nanoHA (Group1), gutta-percha-nano HA+composite (Group 2), gutta-percha-nano HA+MTA (Group 3), resilon-epiphany (Group 4),resilon-epiphany+composite (Group 5), and resilon-epiphany+MTA (Group 6). Fracture resistance of all samples was measured using the Instron testing machine. Three samples from each group had the depth of their fracture line measured by Micro CT Scan, and 2 samples from each group had their fracture pattern illustrated using SEM. Results: The highest fracture resistance was observed in Group +ve, followed by Groups 3, 6, 5, 2, 4, 1, and Group -ve, with values (in N) of: 1598 (641.0), 1190.5(424.2), 1164.7 (489.4), 821.2 (220.9), 683.4(179),658.4 (211.3), 658.4 (99.0), 158.3(49.3), respectively. Statistical analysis for root fracture resistance showed highly significant difference between all groups with p value < 001.Conclusions: Micro CT Scan and SEM analysis indicated the ability of MTA to withstand vertical force.

Sealing ability of gutta-percha/Nano HA versus Resilon/Epiphany after 20 months using an electrochemical model: an in vitro study

Aim: To evaluate the sealing ability of gutta-percha-nano-HA and Resilon-Epiphany by electrochemical method and micro-computed tomography (CT) scan at 48 h and 20 months using three different obturation techniques (cold lateral condensation technique, warm vertical condensation - System B, and warm vertical condensation with vibration - Down-Pak). Methods: 150 human mandibular single-rooted premolars were prepared and randomly allocated into 6 groups of 25 specimens each, and filled with either gutta-percha-nano HA or Resilon-Epiphany with the three different obturation techniques (cold lateral, warm vertical - System B, and warm vertical with vibration - Down-Pak). Electrochemical microleakage method was used to measure the microleakage after 48 h and after 20 months, and a micro-CT Scanner 1072 was used to evaluate the quality of obturation after 48 h. Results: Group 6 (Resilon-epiphany/Down-Pak technique) had the highest microleakage value, followed by Group 2 (Gutta-percha-nano HA/ System B technique), Group 4 (Resilon-Epiphany/Lateral condensation technique), Group 3 (Gutta-percha-nano HA/Down-Pak technique), Group 5 (Resilon-Epiphany/System B technique), and Group 1 (Gutta-percha-nano HA/Lateral condensation technique) with the values of 4.69 (6.06) KÙ, 3.88 (2.92) KÙ, 3.77 (3.75) KÙ, 3.38 (3.92) KÙ, 2.64 (2.90) KÙ, and 2.44 (4.34) KÙ, respectively. No significant difference in the quantity of leakage was observed for each root in each group between the two tested filling materials and their sealers (p=0.143). Micro CT scan investigations revealed more micro-voids in the Resilon-Epiphany Group obturated with Down- Pak technique. Conclusions: Nano-hydroxyapatite sealer with gutta-percha filling material provided a reasonable seal compared with Epiphany sealer and Resilon filling material.

An agar diffusion study comparing the antimicrobial activity of Nanoseal with some other endodontic sealers.

The aim of this study was to evaluate the antimicrobial activity of a new experimental nano-hydroxyapatite epoxy resin-based sealer (Nanoseal) with several other commercially available sealers; AH26, Tubliseal, Sealapex and Roekoseal against Enterococcus faecalis, Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus sobrinus and Escherichia coli for up to 7 days. Agar diffusion was used in this study. Fifty Muller-Hinton agar plates were prepared and divided into five experimental groups (n = 10), for each micro-organism. Another 10 agar plates were used as positive and negative controls. Endodontic sealers were tested against each micro-organism. Inhibition zones produced were recorded. The results of this study showed that all test materials exhibited inhibition zones towards the tested micro-organisms for 7 days except for Roekoseal, which showed no inhibition zones. Nanoseal and AH26 exhibited similar zones of inhibition. Significant difference was found between Nanoseal and the other tested sealers (P < 0.001).