An Evaluation of Ion Released from Two Brands of Brackets in Three Types of Mouthwashes

Background: Mouthwashes used widely as ancillary to mechanical oral hygiene methods. Little information provided about the effect of mouthwashes on ions released from orthodontic brackets. Therefore, the present study has been established to evaluate the effect of different mouthwashes on the ion release and the biocompatibility of two


INTRODUCTION
Plaque control is the major consensus during orthodontic treatment to prevent the occurrence of cavities and periodontal inflammation (1) .Therefore during orthodontic treatment, practitioners recommend that their patients use mouthwashes, since most of them are adolescents who do not always follow a satisfactory oralhygiene regimen and have a high risk of dental caries (2) .
In the oral environment, orthodontic appliances are exposed to potentially damaging physical and chemical agents which may cause metallic corrosion (3) .Recent improvements in the composition and quality of orthodontic alloys have significantly increased their biocompatibility and stability inside the oral cavity.However the release of metal ions from dental alloy is a phenomenon that cannot be avoided; it's difficult to find a material that will be fully stable within an organism and will show no sign of biodegradation (4) .Therefore during the last decade, there has been increased interest among dental and biomedical professionals in the side effects associated with the use of biomaterials, especially the metallic materials; fixed appliances in orthodontics involve brackets and archwires that are metallic.These brackets are exposed to the oral cavity, which is a potentially hostile environment where electrochemical corrosion phenomena can occur.Thus, orthodontic brackets and other auxiliary components should be made of highly corrosion resistant metals and metal alloys (5) .

MATERIALS AND METHODS
The sample consists of 80 premolar stainless steel brackets, which were divided according to their manufacture (Dentaurum and OrthoTechnology) into two groups each group contained 40 brackets that each subdivided into four subgroups, one of these subgroup immersed in 15 ml of deionized distilled water (controlled group), pH 7.5, while the second one immersed in 15 ml of Corsodyl mouthwash, pH 4.49, furthermore the third one immersed in 15 ml of Listerine mouthwash, pH 3.8 and finally the forth one immersed in 15 ml of Silca herb mouthwash, pH 7.85.
After that each individual capped -glass tube which was marked with specific color that represents the brand of bracket was filled with 15 mL of each different mouthwash and deionized distilled water using measuring glass cylinder then all the capped -glass tubes were incubated in an incubator set at a constant temperature of 37°C for 45 days.
After incubation period, the samples were prepared for estimation of ions concentration included copper, manganese, nickel, chromium and iron by using atomic absorption spectrophotometer following standardized procedure.
The Concentrations of Copper, Nickel, and Chromium were determined by using flame atomic absorption spectrophotometer at wave lengths for each element, while the concentration of manganese was determined by using furnace atomic absorption spectrophotometer and finally Concentration of iron was determined by colometric method with spectrophotometer, iron kit used.

RESULTS
The amount of ions released from the stainless brackets were compared between two different brands (Dentaurum and OrthoTechnology) in each mouthwash and among different widely used mouthwashes (Corsodyl, Listerine and Silca herb) and deionized distilled water that used as a control medium.

Iron Ions Released:
Reviewing table1, the results revealed that the amount of iron ions released, in all types of mouthwashes, from the brackets of Dentaurum Company were higher than that released from OrthoTechnology Company with a highly significant difference as indicated by independent sample t-test.
The amount of iron ions released from the brackets of Dentaurum Company were higher in Listerine, followed by deionized distilled water, Silca herb and the least amount were released from Corsodyl mouthwash with a highly significant difference as indicated by ANOVA test.
Regarding OrthoTechnology Company, the amount of iron ions released were higher in deionized distilled water followed by Silca herb then Listerine and Corsodyl with a highly significant difference.
For both companies, LSD test showed a highly significant difference when comparing the iron ions released between each two mouthwashes.

Chromium Ions Released:
As can be seen in table 2, the results revealed that the amount of Chromium ions released, in all types of mouthwashes, from the brackets of Dentaurum Company were higher than that released from OrthoTechnology Company with a highly significant difference as indicated by independent sample t-test except for silca herb mouthwash which showed non-significant difference (p>0.05) and in Corsodyl mouthwash OrthoTechnology showed higher amount of the ions.
The amount of Chromium ions released from the brackets of Dentaurum Company were higher in Listerine followed by Corsodyl, deionized distilled water and the least amount were released from Silca herb mouthwash with a highly significant difference as indicated by ANOVA test.
Regarding OrthoTechnology Company, the amount of Chromium ions released were higher in Listerine followed by Corsodyl then deionized distilled water and Silca herb with a highly significant difference.
For both companies, LSD test showed a highly significant difference when comparing the Chromium ions released between each two mouthwashes.

Nickel Ions Released:
Reviewing table 3, the results revealed that the amount of Nickel ions released, in all types of mouthwashes, from the brackets of Dentaurum Company were higher than that released from OrthoTechnology Company with a highly significant difference as indicated by independent sample t-test.
The amount of Nickel ions released from the brackets of Dentaurum Company were higher in deionized distilled water followed by Corsodyl, Listerine and the least amount were released from Silca herb mouthwash with a highly significant difference as indicated by ANOVA test.
Regarding OrthoTechnology Company, the amount Nickel of ions released were higher in deionized distilled water followed by Corsodyl then Silca herb and Listerine with a highly significant difference.
For both companies, LSD test showed a highly significant difference when comparing the Nickel ions released between each two mouthwashes.

Copper Ions Released:
Reviewing table 4, the results revealed that the amount of Copper ions released, in all types of mouthwashes, from the brackets of Dentaurum Company were higher than that released from OrthoTechnology Company with a highly significant difference as indicated by independent sample t-test.
The amount of Copper ions released from the brackets of Dentaurum Company were higher in Listerine followed by Corsodyl, deionized distilled water and the least amount were released from Silca herb mouthwash with a highly An evaluation of Pedodontics, Orthodontics and Preventive Dentistry 157 significant difference as indicated by ANOVA test.
Regarding OrthoTechnology Company, the amount of Copper ions released were higher in Listerine followed by deionized distilled water then Corsodyl and Silca herb with a highly significant difference.

Manganese Ions Released:
Reviewing table 5, the results revealed that the amount of Manganese ions released, in all types of mouthwashes, from the brackets of Dentaurum Company were higher than that released from OrthoTechnology Company with a highly significant difference as indicated by independent sample t-test.
The amount of Manganese ions released from the brackets of Dentaurum Company were higher in Listerine followed by deionized distilled water, Silca herb and the least amount were released from Corsodyl mouthwash with a highly significant difference as indicated by ANOVA test.
Regarding OrthoTechnology Company, the amount of Manganese ions released were higher in Listerine followed by deionized distilled water then Silca herb and Corsodyl with a highly significant difference.
For both companies, LSD test showed a highly significant difference when comparing the Manganese ions released between each two mouthwashes.

DISCUSSION
Brackets from two different manufactures were used, which are widely used in orthodontic department in the college of dentistry at Baghdad University.
Adhesive resins were not used on the base of brackets in this study to prevent other sources of ion release (6) .Therefore, the exposed surface for ion release was approximately twice that of clinical conditions because the bracket bases would be covered with a bonding material in clinical use (3,7) .
Mouthwashes usually used twice a week for about 1 minute, it is also recommended that after mouthwash the patient must not eat, drink, and rinse, so the components of mouthwash are present for a long time, and it is difficult to determine the exact duration of contact between brackets and mouthwashes.In this study we assumed that each time the mouthwash was present for 6 hours in a patient's mouth (24 months, twice a week about 69,000 minutes), therefor the brackets were immersed in mouthwashes and incubated for 45 days (45 days about 64,000 minutes) (3,7,8) .

The level of ions released from different companies
results revealed that the amount of released, in all types of mouthwashes, from the brackets of Dentaurum Company was higher than that released from OrthoTechnology Company with a highly significant difference as indicated by independent sample t-test except for chromium ion released in Silca herb mouthwash was non-significant differenceand in Corsodyl mouthwash OrthoTechnology showed higher amount of the ions, this agree with Lin et, al., (9) who found that the brand of the commercial SS brackets had a significant influence on the corrosion resistance, and the difference in corrosion resistance might be related to the different surface characterizations, such as surface residual stress and metallurgical factors, produced during the various manufacturing processes, instead of the surface roughness and preexisting defect.
For nickel ions released from brackets in the various solutions, the maximum release were in deionized water and the next highest were in chlorhexidine mouthwash, this agrees with Patel et al and Danaei et, al., (3,7) .The reason might be because deionized water has an extremely low concentration of ions, and the lack of ions makes this solvent one of the most aggressive solvents known, the corrosion of different metals and alloys as a result of immersion in deionized water has been studied (10) while the group immersed in chlorhexidine this could be attributed to the corrosiveness of chlorhexidine compared with the other two mouthwashes; this agrees with previous reports about the irritating effects of chlorhexidine (3,7,11,12)   .Furthermore Listerine and Silca herb mouthwashes revealed less amount of nickel ions, this may be due to the composition of mouth wash itself this agrees with House et, al., (13) , who stated that the level of corrosion of any metal depends on the chemistry of the solvent in which it is d.f = 39 p-value=0.000***nickel is a concern, and the natural capacity to eliminate nickel exceeds the accumulation capacity, the risks are minimal (20) .However, clinicians should be aware that the release of metal ions might cause a local hypersensitivity reaction at oral soft-tissue sites, such as mild erythema or redness with or without edema (21) .Also, severe gingivitis can be related not only to poor oral hygiene but also to a hypersensitivity reaction to nickel or chromium ions released from stainless steel (22)(23) .

( 1 )
Master Student.Department of Orthodontics, College of Dentistry, University of Baghdad.(2) Assistant Professor, Department of Orthodontics, College of Dentistry, University of Baghdad.

Table ( 4): Copper Release from Brackets of Different Companies in Different Mouthwashes Groups Dentaurum OrthoTechnology Company difference Mean
S.D. Min.Max.Mean S.D. Min.Max.