Showing 8 results for Hydroxyapatite
V. Mortazavi , Mh. fathi ,
Volume 13, Issue 1 (4-2000)
Abstract
Characterization of bioceramics coating and evaluation of the influence of kind of coating on the implantation has been developed in recent years.Different bioceramics coating like calcium phosphate, hydroxyapatite, fluorapatite and bioglass were coated on dental and orthopedic implants. In-vitro and in-vivo experiments were done for evolution of implant success and reliability and study of factors, which may influence the results.Researches indicate that different bioceramic coating may affect the bone bonding mechanism.Biodegredable calcium phosphate coating can be resorbed and be replaced with bone tissues.Hydroxyapatite cause earlier stabilization of dental implant in surrounding bone (biological fixation) and reduce healing time. Bioglass can protect substrate and provide interfacial attachment to bone.
Mh. Fathi , V. Mortazavi , Sb. Moosavi ,
Volume 15, Issue 3 (6-2002)
Abstract
Nowadays, application of implants as a new method for replacing extracted teeth have been improved. So, many researches have been performed for improving the characteristics of implants. The aim of this study was to design and produce a desired coating in order to obtaining two goals including improvement of the corrosion behavior of metallic endodontic implant and the bone osseointegration simultaneously. Stainless steel 316L (SS), cobalt-chromium alloy (Vit) and commercial pure titanium (cpTi) were chosen as metallic substrates and hydroxyapatite coating (HAC) were performed by plasma-spraying (PS) process on three different substrates. A novel double layer Hydroxyapatite/Titanium (HA/Ti) composite coating composed of a HA top layer and a Ti under layer was prepared using PS and physical vapor deposition (PVD) process respectively on SS. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure, morpholgy and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens behavior as an indication of biocmpatibility. Results indicated that the cpTi possesses the highest and SS the lowest corrosion resistance (highest corrosion current density) between uncoated substrates. This trend was independent to the type of physiological environment. The HA coating decreased the corrosion current density of HA coated metallic implants but did not change that trend. HAC acted as a mechanical barrier on the metallic substrate but could not prevent the interaction between metallic substrate and environment completely. The HA/Ti composite coating improved the corrosion behavior of SS. The corrosion current density of HA/Ti coated SS decreased and was exactly similar to single HA coated cpTi in physiological solutions. The results indicated that HA/Ti composite coated SS could be used as an endodontic implant and two goals including improvement of corrosion resistance (biocompatibiiity) and bone osseointegration could be obtained simultaneously.
Hadi Asgharzadeh Shirazi, Mohammadreza Mallakzadeh,
Volume 27, Issue 2 (6-2014)
Abstract
Background and Aims: Hydroxyapatite coating has allocated a special place in dentistry due to its biocompatibility and bioactivity. The purpose of this study was to evaluate the relation between the hydroxyapatite thickness and stress distribution by using finite element method.
Materials and Methods: In this paper, the effect of hydroxyapatite coating thickness on dental implants was studied using finite element method in the range between 0 to 200 microns. A 3D model including one section of mandible bone was modeled by a thick layer of cortical surrounding dense cancellous and a Nobel Biocare commercial brand dental implant was simulated and analyzed under static load in the Abaqus software.
Results The diagram of maximum von Mises stress versus coating thickness was plotted for the cancellous and cortical bones in the range between 0 to 200 microns. The obtained results showed that the magnitude of maximum von Mises stress of bone decreased as the hydroxyapatite coating thickness increased. Also, the thickness of coating exhibited smoother stress distribution and milder variations of maximum von Mises stress in a range between 60 to 120 microns.
Conclusion: In present study, the stress was decreased in the mandible bone where hydroxyapatite coating was used. This stress reduction leads to a faster stabilization and fixation of implant in the mandible bone. Using hydroxyapatite coating as a biocompatible and bioactive material could play an important role in bone formation of implant- bone interface.
Hanieh Nojehdehyan, Maryam Torshabi, Fahimeh Sadat Tabatabaei,
Volume 27, Issue 3 (9-2014)
Abstract
Background and Aims: Until now, different types of scaffolds are presented for hard tissue engineering and the research continues to find the best scaffold. The aim of this study was to prepare scaffolds using two types of composite materials, ChitosanTriCalcium Phosphate (C/TCP) and ChitosanTriCalcium Phosphate/ Hydroxy apatite (C/TCP/ HA) and to add either 10% or 20% gelatin to compare their influence on swelling ratio of the scaffolds and on their affinities towards Dental Pulp Stem Cells (DPSCs).
Materials and Methods: Composite scaffolds containing 10 or 20 percent of gelatin were prepared by freeze drying method. To determine the percentage of water absorption, swelling ratio studies were performed. Cell attachment and cell viability of the composite scaffolds were studied using Scanning Electron Microscopy (SEM) and MTT ( dimethyl-thiazol-diphenyltetrazolium bromide ) assay. Data were analyzed using ANOVA and Turkey’s post hoc test. A P-value of <0.05 was considered to be statistically significant.
Results: The C/TCP scaffold and scaffolds containing 20% gelatin showed good swelling character. The macroporous composite scaffolds exhibited different pore structures. The biological response of DPS cells on C/TCP scaffold, C/TCP scaffold containing 20% gelatin, and C/TCP/HA scaffold was superior in terms of cell attachment, proliferation, and spreading compared to the other scaffolds (P<0.05).
Conclusion: Considering the limitations of this in vitro studies, the results demonstrated that enhanced gelatin content in the C/TCP scaffolds do not improve initial cell adhesion and proliferation of the DPSCs on these scaffolds.
Haghgoo Roza , Rezvani Mohammad Bagher , Haghgoo Hamid Reaza , Ameli Nazila , Zeinabadi Mehdi Salehi ,
Volume 27, Issue 4 (1-2015)
Abstract
Background and Aims: Dental caries is one of the most common infectious diseases which could be prevented in various ways. The aim of the present study was to evaluate the effect of a toothpaste containing different concentrations of nano-hydroxyapatite on the remineralization of incipient caries.
Materials and Methods: 9 sound first premolar teeth of maxilla and mandible were sectioned to four pieces. 6 specimens were stored in distilled water as control group. The remaining 30 specimens were demineralized for 72 hours and then their microhardness was measured. 0, 0.5, 1, 2 and 5% wt nano-hydroxyapatite were added to the solution of distilled water and toothpaste. Specimens were divided into 5 groups (N=6) and after demineralization, each group were randomly immersed in the above-mentioned solutions for 15 minutes. Next, specimens were kept in artificial saliva for 1 hour followed by immersion in the related remineralizing solution for another 15 minutes. This procedure was repeated for 5 days. Finally, the microhardness of the teeth was measured. Data were analyzed using repeated measures analysis of variance (ANOVA).
Results: The microhardness of demineralized teeth was increased following exposure to different concentrations of nano-hydroxyapatite, but this increase was not statistically significant (P=0.62).
Conclusion: Nano-hydroxy apatite can enhance remineralization and increase the tooth microhardness although this increase was not significant.
Haghgoo Roza , Haghgou Hamid Reza , Abbasi Farid , Tavakkoli Mohammad ,
Volume 27, Issue 4 (1-2015)
Abstract
Background and Aims: The main cause of erosion is acid exposure . Side effects of erosion necessitate therapeutic agents’ uses. The aim of this study was to investigate the effects of nano- hydroxy apatite in tooth remineralization following exposure to soft beer.
Materials and Methods: This in vitro experimental study was conducted on 18 human impacted third molars that had been surgically extracted. The microhardness of specimens was measured. Then teeth were exposed to soft beer and their secondary microhardness was measured. The teeth were divided into 2 groups (water and nano-hydroxy apatite solution) and were placed on 9 orthodontics appliances and delivered to 9 volunteers. These volunteers placed the tooth on one side in water for 5 minutes and the tooth in opposite side in nano-hydroxyapatite solution. This application was repeated 6 times a day for 10 days. The microhardness of teeth was measured again. Data were analyzed using Paired T-test.
Results: The tooth enamel microhardness reduced after exposure to soft beer significantly (P=0.04). The microhardness of 9 teeth after being in water showed significant changes (P=0.012). The microhardness of 9 teeth significantly changed after exposure to nano -hydroxyapatite solution (P=0.001) .
Conclusion: Based on the results of this study, 10% solution of nano- hydroxy appatite could restore the erosive lesions .
Rahelesadat Mirseifi Nejad Naini, Alireza Daneshkazemi, Fahime Shafiee,
Volume 31, Issue 2 (9-2018)
Abstract
Background and Aims: Increased tooth sensitivity is a common dental problem. One of the mechanisms of dentin hypersensitivity treatment is blocking dentinal tubules. The aim of this study was to compare the average closing dentinal tubules affected by carbonated Nano-hydroxyapatite and fluoride toothpaste using scanning electron microscope (SEM).
Materials and Methods: The enamel of gingival buccal crown surfaces of 42 sound maxillary premolars teeth were removed until the dentin surfaces were exposed. The dentine specimens of 3×3 mm were prepared. The specimens were washed by distilled water after etching and randomly divided into 6 groups. 3 groups were interfered with the carbonated nano-hydroxyapatite toothpaste and the other three groups interfered with Colgate toothpaste in 3, 7 and 14 days. The samples were examined by SEM to check the status of dentinal tubules. Then, they were evaluated by two researchers according to the Hulsmann index. Data were analyzed by using SPSS23 software and Kruskal-Wallis statistical test. The significance level of 0.05 was considered.
Results: The amount of dentinal tubules closure by the two toothpastes was significantly different. This difference was higher in the hydroxyapatite toothpaste than fluoride which were (P=0.024, 0.004 and 0.000), respectively. There were no significant differences among the groups in 3,7 and 14 days (P=0.230, 0.069, 0.537).
Conclusion: The toothpaste containing carbonated nano structural hydroxyapatite was more successful in closing dentinal tubules than Colgate toothpaste in short period of time.
Abdolrahim Davari, Farnaz Farahat, Sepideh Abbasi,
Volume 35, Issue 0 (5-2022)
Abstract
Background and Aims: Different factors play a role in causing tooth decay. Modern dentistry is looking for a way to prevent tooth decay and suggests different ways to increase remineralization. The aim of this study was to evaluate the effect of nanohydroxyapatite toothpaste and mouthwash on remineralization of primary enamel lesions and obstruction of tubules.
Materials and Methods: In this study, 90 human extracted central teeth were used. Artificial decay was induced by placing the specimens for 72 hrs in a demineralization solution in an incubator at 37 °C. Hardness of the specimens was determined by a microhardness test before any surface treatment. The specimens were then divided randomly into 6 groups of 15. For 1-6 groups, the specimens were subjected to a pH cycling for 14 days, which included 3 hrs of demineralization and 21 hrs of remineralization. At the same time, 1-3 groups were in contact with diluted toothpaste in a ratio of 1:3 with deionized water at a rate of 5 ml twice a day for two min. Eac specimen of 4-6 groups was exposed to 5 ml of three types of mouthwashes for one min. Then, the specimens were cut in the buccolingual direction in order to simultaneously evaluate the dentinal tubules and Vickers microhardness test was performed again and the before and after microhardness values were compared. Then, the percentage of deposition on the surface and tubule obstruction were analyzed using SEM (Scanning electron microscope) (P=0.006). Data were analyzed using SPSS24 software bu the descriptive statistics, ANOVA analysis of variance, and multiple Tukey comparisons.
Results: The results of analysis of variance test showed that there was a statistically significant difference in the microhardness changes between study groups (P=0.006). Also, in-group analysis of microhardness changes, there was a significant difference (P<0.0001). Besides, only in the group containing 0.5% nanohydroxyapatite toothpaste, more than 50% tubule deposition and obstraction was observed (P<0.05).
Conclusion: According to the present study, nanohydroxyapatite can be one of the treatment strategies to repair incipient lesions of teeth and the addition of nanohydroxyapatite, preferably to toothpaste, increases the dental microhardness.
