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Zinc and its alloys are considered as the most promising biodegradable metal material for clinical applications due to the appropriate biological degradation rate in the body, absorbable biodegradation products, and excellent biocompatibility. However, the strength of pure zinc is usually lower than the mechanical values required in metal implants such as bone fixtures or stents, which limits the wider applications of this metal. also excessive ion release (Zn2+) in the biological environment leads to high cell death and lack of acceptance by the host tissue. In order to improve the mechanical strength and adjust the release of Zn2+ ions, this metal can be alloying with other metal elements as well as various surface modification processes to increase biocompatibility. In this review, The progress that has been made in the field of increasing strength and biocompatibility, are stated. Finally, The direction of research in this field and guidance with the aim of developing absorbable zinc alloys with high performance in the future, has been discussed.

Biocompatibility in some respects depends on the corrosion behavior of dental alloys. The purpose of this study was to investigate the effect of surface passivation of a cobalt chromium alloy on corrosion behavior.

In this experimental study, 20 samples of Flexicast dental alloy were prepared according to ADA97 standard and after casting, the samples were polished to the mirror surface. Electrolytic passivation was employed by immersion of one first series of samples in Na2SO4 solution for 24 hours at room temperature. The second series of specimens was not passivated. Surface morphology and chemical composition before and after passivation studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to investigate the corrosion behavior in saline solution. Corrosion test was conducted for 4 weeks and surface of specimens were monitored each week. The chemical composition results were analyzed by Kruskal-Wallis and Mann-Whitney tests using SPSS17 software.

The passivated specimens exhibited higher corrosion resistance while pitting corrosion was detected in all specimens. Kruskal-Wallis test showed a significant difference between the two groups of passivated and non-passivated samples. The Mann-Whitney test showed that the cobalt, chromium and oxygen ions were significantly different between the two groups (P <.0.05).

The rate of corrosion and formation of pits were significantly reduced by surface passivation.

Corrosion and Scaling in distribution network pipes is one of the most important indices in water quality evaluation and one of the most common environmental phenomena that deteriorate water quality, color, odor, taste and also increases the concentration of heavy metals in water. Corrosion causes entry of bye-products to water and decreases pipe life and sedimentation, reduces the flow rate and the efficiency of valves and fittings. The purpose of this study was to determine the corrosion or Scaling state of drinking water in Mashhad in 2017.
Material and In this study, 72 samples were taken during 2017 to evaluate water quality characteristics, and analyzed based on the standard methods. Then, three indices including Langlier, Ryznar and Aggressiveness Indices were programmed in Excel software and based on this, Corrosion and scaling potential of drinking water were determined. Results showed that the averages of Langlier, Ryznar and Aggressiveness Indices for water were 0.14±0.48, 6.67±0.38 and 12.23±0.23, respectively. According to the Langlier and Ryznar indices, 86.1% of total samples had low scaling potential and according to Aggressive index 97.2% of total samples had scaling. Also, the results showed that 58.33% of the samples were low scaling in spring and other samples were high scaling. In addition, in the summer, 33.3% of the total samples were high scaling and other samples were low scaling. The results showed that drinking water of Mashhad city was Scaling. Therefore, it is necessary to take measures to control scaling in distribution network pipes, especially in areas located in high scaling zones.

Corrosion may be a consequence of disinfecting and cleansing of partial denture chromium – cobalt frameworks using chemical disinfectants and cleansers. There is short information in literature about the effect of these solutions, in comparison with each other, on the corrosion rate of chromium – cobalt alloy. The present study was designed to compare corrosion rate of the chromium – cobalt alloy in disinfecting solutions.
Material & In this experimental in-vitro study, corrosion rates of 35 chromium-cobalt immersed in7disinfecting solutions were determined. As a complementary test , samples were immersed in two groups of solutions which showed the least and the most corrosion rates as measured by electrochemical tests for a period of one week and their surface and also surface of one untreated control sample was photographed under a scanning electron microscope . Corrosion rates obtained, were statistically analyzed using variance analysing test and multiple comparisons were made using Tukey HSD and Dunnett tests.
The corrosion rates of chromium cobalt sample in the studied solutions from the highest to lowest , were : Sodium Hypochlorite 1%, Fittydent 1 tab/250ml , Micro 10 5% , Korsolex Plus 3% , Deconex 53 Plus 2% . Corrosion rates were statistically different in the studied solutions (P The present study indicated that Sodium Hypochlorite at the concentration of 1% or more for the purpose of disinfection and cleansing of chromium-cobalt not be used.

One of the major problems of water utilization scaling and corrosion, which is a physical and chemical reaction between a metal and its environment is done and leads to material changes its properties. In this study corrosion and scaling index gained for malekshahi city's drinking water supply.
The desired parameters in accordance with the standard method of water and wastewater tests were tested and corrosion index Langelier, Rayznr, corrosion and Puckorius were calculated using equations and diagrams.
The results indicate that in accordance with the indices of corrosion Langelier index (-o.4), Rayznr (7.59), corrosion (11.59) and Puckorius (6.44), in terms of drinking water, city malekshahi the corrosive medium.
Evaluation of corrosion indices showed that drinking water is corrosive malekshahi city. And to compare parameters of water quality in the city malekshahi indicates that the concentration measured parameters except alkalinity is all in the standards of Iran and EPA.

Corrosion and scaling are the main problems that water facilities still face with them. Corrosion can caused great financial losses and health damage to the system, and consumers. Blockages and pressure drop in the network are another disadvantage of scaling. The aim of present study was to determine the corrosive and scaling potential in drinking water resources of Shahrood city.
This crosses-sectional study was conducted over 4 seasons in 2013 years. 1104 samples were examined using Langelier (LSI), Rayznr (RSI), aggressive (AI) and Pokurious (PSI) indices to determine the corrosive and scaling potential in drinking water resources of Shahrood city. To compare the mean values of each indices, the results were analyzed using t-test.
The results indicate that the drinking water resources of Shahrood according to the Langelier index equals -1.03 with a standard deviation of 0.11, according to Rayznr index equals 9.72 with a standard deviation of 0.17, based on Aggressive index equals 12.10 with a standard deviation of 0.14, based on Pokurious index equals 9.59 with a standard deviation of 0.13 respectively. The difference between the mean values of the four studied seasons also were significant. P-value Comparison of four indices and obtained results showed that drinking water resources in Shahrood was corrosive, therefore, it is suggested that the city's water resources should constantly assessed and try adjusting the pH and control of other affecting factors on the corrosion such as chloride, dissolved oxygen and sulfate concentrations to reduce corrosion.

Scaling and corrosion is one of the most important index in water quality evaluation. The objective of this study was to determine the corrosion and scaling potential of drinking water network in south of Shiraz city, Iran.
In this cross-sectional study, this network was divided into 9 sections and, regularly 3 samples from each section were taken. For this study, some important indexes about the corrosion and scaling such as, Langelier, Rayznr, Larson and Puckorius were considered. These indexes were calculated by using some parameters consists of temperature, Calcium hardness, alkalinity, Sulfate, Chloride, total dissolved solids, and pH in 2013.
The results showed that total hardness contents is very high in all of parts of the water distribution network in south of Shiraz city. The calculated results showed that the mean and standard deviation values of LSi, RSi, LS and PSi were equal to -0.46 ± 0.39, 7.4 ± 0.17, 1.3±0.15 and 7.15 ± 0.33, respectively.
The results showed that despite of the most of parameters in the study areas are in suitable status compared to the national standard but according to stability index the water network of south of Shiraz has a variable corrosion ratio from low to moderate.

To evaluate of corrosion products in dentin after removal of old Amalgams with and without roughness Twenty Class II cavities were prepared on extracted premolars then Randomly were divided into four groups according to how they were restored. Group 1: Lightcured packable composite to establish a microleakage baseline; Group 2: A high copper Amalgam; then stored in 37C normal saline for 6 months to create amalgam corrosion products. Group 3: Identical to Group 2, but later the amalgam was replaced with composite leaving the cavity walls intact. Group 4: Identical to Group 3 except the cavity walls were extended 0.5 mm after amalgam removal prior to insertion of the composite. There are 5 specimens in each four groups for EDX analysis.Evaluation of EDX analysis was descriptive. Corrosion products were detected in Groups 1,2,3 but were not detected in Group 4. After amalgam removal, roughing dentinal walls could remove the corrosion products penetrating it.

Occurrence of corrosion and deposition in drinking water in distribution system can leads to economic and health damages. The aim of this study was to investigate the corrosion and precipitation potential of drinking water in Kerman distribution system. This cross-sectional study was performed from September to November of 2011. For determining the chemical quality of Kerman drinking water, 40 samples with 2-4 L were taken in glass container and then were analyzed. The physical and chemical quality of samples was determined and the potential of corrosion and precipitation of waters were analyzed in terms of four corrosion indicesie. Langelier Index (LI), Ryznar Index (RI), Pockorius Index (POI) and Aggressiveness Index (LS). The test methods were adopted from “standard methods for water and wastewater examination” and the obtained data were analyzed with description parameters. Based on the results, chemical quality of water in Kerman Distribution system was under the Iranian national standard and WHO guideline. The results showed that the LI index for >90% was above zero and RI index indicated that >82% of samples was below 7. According to POI and LS index, the deposition rate was 60 and 90%, respectively. By survey of LI, RI, POI and Ls indexes, it was found that Kerman distribution system water has scaling (precipitation) potential. The chemical quality of Kerman distribution system water is imbalance thus resulting in the scale formation in water distribution system and other equipments. In addition, to stop economical loss the planning for water quality stabilization is necessary.

Kashan rural water and wastewater company (KRWWC) in Iran is facing a multitude of problems including some potential health risks associated with pipe corrosion byproducts, their early deterioration, the occasional interruption of the water supplies and also huge operation costs. Therefore, this study aimed to evaluate the corrosive and scale-forming properties of water in Kashan villages.

This descriptive study was carried out on 151 water samples taken from 39 rural water supplies in 4 stages during 2007-9. All samples were analyzed for total hardness, calcium, alkalinity, total dissolved solids (TDS), bicarbonate, temperature and pH according to the last edition of the Standard Methods Book and then Ryznar, Langelier and Puckorius indices were calculated. Data were analyzed using Fisher's exact test and Paired t-test followed by Bonferroni correction.

According to Ryznar, Puckorius and Langelier indices, 95%, 97% and 74% of the water supplies in all seasons were corrosive, respectively. Moreover, according to the three above-mentioned indices, 18 villages (46.15%) under the coverage of Kashan rural water and wastewater company have always had corrosive water and there was also no significant difference in water quality between the seasons.

Results showed that most water supplies are corrosive and a few of them are scale-forming. Hence, application of suitable plumbing utensils, turn on/off bypass pumps and valves and if necessary, appropriate water treatment are recommended.

Corrosion and sedimentation potential is one of the main factors in water quality control issues. Water tendency towards each of them, can be play very effective role in the transmission and distribution of drinking water in terms of economic and health aspects. The purpose of this study was evaluation of chemical quality, corrosive and sedimentation rate of drinking water in Ardabil water supply network and providing relevant solutions for probable problems. In a cross-sectional research conducted in autumn 2009, the city was divided into 12 blocks and water samples were taken in two instances (in the first half of October and the second half of December). Parameters of alkali, calcium hardness, electrical conductivity, temperature and pH were determined. Water samples were handled according to standard procedures, and corrosion and sedimentation potential were estimated using indicators Lanzhlyh (LSI) and Rayznr (RSI). The results of tests and calculations showed that the respective value for average of LSI index in the first and 2nd stage of water sampling was -0.23 and -0.46, and the average for RSI index in the first and 2nd stage of sampling was 7.98 and 8.24, respectively. Based on LSI index, drinking water in the water supply system has a tendency to corrosion in 9 and 12 stations in the first and second sampling campaigns, respectively; with the other stations tending to have sedimentation. However, according to RSI index six stations had tendency to corrosion and others was balanced in the first samples. For the second samples, ten stations tend to have corrosive property and the others had conditions of relative equilibrium. Based on the results obtained, water in Ardabil drinking water supply have slight tendency to corrosion and water quality must be controlled for the relevant parameters e.g. pH, alkali, and hardness. Application of corrosion-resistant pipes and materials should be considered in drinking water networks.

Aims. Lack of chemical quality control of drinking-water (DW) in distribution systems may cause corrosion, precipitation and ultimately leads to economics and health damages. The goal of this study was to evaluate the chemical quality of DW in military centers and predict the potential of corrosion and precipitation within those DWs. Methods. In this cross-sectional and descriptive study the chemical quality of DW (underground) in 9 military centers located in different water basin of Iran were investigated in four different seasons. In any season, 3 grab samples with 2-3L of water volume have been obtained. All of the samples were collected, stored and preserved in glass or polyethylene container and analyzed based on standard methods. The potential of corrosion and precipitation of DWs were calculated by Langelier saturation Index (LSI), Aggressive Index (AI) and Risnar Index (RI). Results. Based on the calculated values of indices, DW of G3, G4 and G5 centers had shown corrosive properties, but other centers showed precipitated properties. Based on LSI, AI and RI the DW of all centers showed a uniform quality of corrosion and precipitation potential. Conclusion. Monitoring of chemical quality, precipitation, corrosion potential and concentration of heavy metals should be considered in DW quality control programs.

One of the characteristics of brackets is resistance to corrosion. Corrosion could disturb dental movement through increasing, the friction between arch wire and slot. It could also cause dental discoloration. The aim of this study was to compare corrosion rate as well as corrosion site of five commonly used brackets in Iran. In this in vitro experimental study, 80 lower central stainless steel brackets (18- slot) from different companies (Mira, Dentaurum, Forte, Joli and 3M) were selected. At first, the brackets were mounted in Rapid impression material and the photographs were taken from six different views for assessing slots, bases, and wings using stereomicroscope device with X50 magnification. Then, each 8 brackets were put into a capped glass containing artificial saliva with PH=7.2 and they were incubated in 37±1°c temperature. The amount of released Nickel ion was measured by Atomic absorption technique after 6 weeks and for each bracket, photographs were taken again from previous views. Statistical analysis was done using Chi-square, Cochrane and Kruskal-Wallis and McNimar tests. The minimum Nickel ion release belonged to 3M brackets (0.86±0.1 PPB) and the maximum release was for Forte brackets (17.49±0.01 PPB). Furthermore, corrosion was seen more in bracket bases (mesh surfaces) and it was less observed in their faces. The order of the Nickel ion release was: 3M>Dentaurum> Joli> Mira>Forte. Corrosion was the highest in the base of the brackets.

Corrosion and precipitation in drinking and sanitary water in distribution systems leads to economic and health damages. The goal of this study was to survey the chemical quality of water in Kharanagh ward in Yazd province and to predict the potential of corrosion and precipitation in these waters.

For determining the chemical quality of water, some cross-sectional samples with 2-4L of water volume were taken. All of the samples were collected, stored and preserved in glass or polyethylene containers and were analyzed based on standard methods. The potential of corrosion and precipitation in waters was calculated by Langelier Saturation Index (LSI), Risnar Index (RI) and decision was made based on calcium carbonate résistance.

Based on the values of LSI, drinking and sanitary waters showed precipitative properties. Based on RI, the waters showed a corrosive quality from the point of corrosion and precipitation potential. Based on calcium carbonate résistance parameter, the waters had precipitative quality.

The chemical quality of water in Kharanagh district is non-balanced that leads to precipitation in water distribution and other equipments thus planning water quality stabilization for the elimination of economics damages is necessary.

Nitinol (NiTi) is the most interesting smart material used in orthopedic surgery and production of artificial muscles. Considering its medical applications, Nitinol biocompatibility is therefore quite important. This issue is discussed in this paper. Nitinol alloy experimentally produced by melting and casting under vacuum plus imported commercial AO samples were implanted in limb tissue of a number of male rats. Twenty one days after the implantation, fibroblast and fibrosis formation in the tissues around the alloy were studied. The amount of the alloy that was corroded under the experimental invitro conditions was acceptable. The biocompatibility of the experimentally made alloy implanted in limb tissue was nearly similar to that of the imported alloy. According to the results obtained, utilization of Nitinol in medicine is scientifically justifiable. Possibilities of its wide industrial and medical applications favorably support the mass production of the alloy in the country and its biocompatible parallels that of the imported material.

Amalgam restorations often tarnish and corrode in the oral environment. The degree of tarnish and the resulting discoloration appear to be dependent on the parameters such as oral environment, oral hygiene, and the particular alloy employed and clinical procedures. The aim of this research was to evaluate and compare the effect of clinical procedures such as carving, carving-burnishing and carving-burnishing-polishing on the tarnish and corrosion behavior of four brand dental amalgams. Method & Materials: Four different type of commercial amalgam alloy powders with different powders with various particles shape (lathe cut, spherical, spheroids) namely Sybraloy (Sy), Cinalux (CL), Oralloy (Or) and cinaalloy (Ca) were studied. A special mold was used to prepare the samples of each type of commercial amalgams. Twenty-one samples of each type of amalgams were prepared. After trituration and condensation, the samples of each type of amalgams were divided into three groups and each group was finished by using one of three procedures carving, carving-burnishing, carving-burnishing-polishing. Electrochemical potentiodynamic tests were performed at a temperature of 37±1 °C in order to determine and compare the corrosion behavior of dental amalgams, as an indication of biocompatibility. The results showed statistically significant differences between the mean corrosion current densities values of three different groups of each type of commercial amalgam (P<0.05). The polished group of each type of commercial amalgams possesses the lowest corrosion current density and the carved group shows the highest corrosion current density (the lowest corrosion resistance). This trend was not affected by the brand and chemical composition of commercial amalgams. The polished Sybraloy amalgam possesses the highest corrosion resistance between four types of polished amalgams and the polished Cinaaloy amalgam showed the lowest corrosion resistance. The similar trend was observed in carved group and carved-burnished group of four types of amalgams. It was concluded that the clinical operations and procedures could influence the tarnish and corrosion behavior of high copper dental amalgams. Polishing procedure increases the corrosion resistance of high copper dental amalgams and is more effective on the corrosion behavior of dental amalgams, which are less corrosion resistant in compare with the dental amalgams that are more corrosion resistant.