Salivary nickel and chromium in subjects with different types of fixed orthodontic appliances

The aim was to investigate nickel and chromium concentrations in saliva of patients with different types of fixed appliances. Saliva samples were collected from 47 orthodontic patients, ages 8 to 30 years. Four samples from each subject were collected: (1) before insertion of the appliance, (2) 1 to 2 days after, (3) 1 week after, and (4) 1 month after insertion of the appliance. A considerable variation in the concentrations of both nickel and chromium was observed. No significant differences were found between the no-appliance samples and the samples obtained after insertion of the appliances. The results suggest that nickel and chromium concentrations of saliva are not significantly affected by fixed orthodontic appliances during the first month of treatment. (Am J Orthod Dentofac Orthop 1997;111:595-8.)     

固定矫治器对青少年口腔念珠菌菌群的影响

目的:探索健康青少年戴用正畸固定矫治器前后口腔念珠菌菌群的变化规律.方法:采用病例自身对照的方法,对研究对象在固定矫治前后的口腔念珠菌菌群进行检测,纵向研究固定矫治器对念珠菌菌群变化的影响.结果:戴固定矫治器后2个月青少年口腔念珠菌混合带菌者比例、总菌落数量有明显增加,念珠菌种类也有明显变化.结论:固定矫治器可引起青少年口腔念珠菌菌群的变化.     

The effects of fixed orthodontic appliances on saliva flow rate and saliva electrolyte concentrations

Summary  Fixed appliance orthodontic treatment may affect local saliva secretion; however, there is limited information available about this respect in the literature. Understanding how fixed appliance orthodontic treatment affects local saliva secretion could provide insight on possible contributions of salivary changes towards decalcification. In this study, we found that during the first month of fixed orthodontic treatment, the whole saliva flow rate, upper labial saliva flow rate and concentrations of whole saliva sodium and chlorine increased significantly, while the concentrations of calcium, phosphorous and potassium in whole saliva decreased. However, all these were in normal levels after 3 months. This study demonstrated that saliva flow rate was increased and saliva electrolytes were changed at early stage when placing fixed orthodontic appliances, which was considered due to increased mechanosensation.     

In vivo study on metal release from fixed orthodontic appliances and DNA damage in oral mucosa cells

Interest in the amount of metal ion intake from dental alloys has grown. Fixed orthodontic appliances usually include brackets, bands, and archwires made of stainless steel, nickel-titanium, or nickel-cobalt alloys, and these can release metal ions. The purpose of this study was to investigate the biocompatibility in vivo of fixed orthodontic appliances, evaluating the presence of metal ions in oral mucosa cells, their cytotoxicity, and their possible genotoxic effects. Mucosa samples were collected by gentle brushing of the internal part of the right and left cheeks of 55 orthodontic patients and 30 control subjects who were not receiving orthodontic treatment. The cells were immediately prepared for cell viability and the comet assay. Nickel and cobalt cellular content was quantified by inductively coupled plasma mass spectrometry (ICP-MS). The results indicate that nickel and cobalt concentrations were 3.4-fold and 2.8-fold higher, respectively, in the patients than in the controls; cellular viability was significantly lower in the patients than in the controls, and there was a significant negative correlation with metal levels. The biologic effects, evaluated by alkaline comet assay, indicated that both metals induced DNA damage (more cells with comets and apoptotic cells). There were significant positive correlations between (1) cobalt levels and the number of comets and apoptotic cells, (2) nickel levels and number of comet cells, and (3) cobalt levels and comet tails. This study corroborates that nickel and cobalt released from fixed orthodontic appliances can induce DNA damage in oral mucosa cells.     

Evaluation of immunologic profile in patients with nickel sensitivity due to use of fixed orthodontic appliances.

The aim of this study was to develop a new approach to testing the impact of nickel antigen on in vitro cell-proliferation assay, to identify adverse reactions to casting alloys among orthodontic patients. Cell-proliferation assay in vitro was used as the basic methodology to assess the influence of such variables as source of nickel antigen, type of serum used to supplement the culture medium, and number of cells in the culture. We selected 35 orthodontic patients who were classified as nickel sensitive and non-nickel sensitive, based on their clinical records. Our results showed that hexahydrated nickel sulfate at 10 microg/mL, 10% of autologous sera, and 2 x 10(5) cells was the best condition for inducing the most marked nickel proliferation response in vitro. This optimized method was able to distinguish nickel-sensitive from non-nickel-sensitive dental patients and also to discriminate those with positive skin tests. Our data suggest that continuous exposure to nickel casting alloys might lead to oral tolerance mechanisms that modulate nickel sensitivity, as evidenced by the lower cell proliferation index in patients undergoing orthodontic treatment over 24 months. Finally, our findings demonstrated a known nickel-induced type 2 immune response and a marked lack of type 1 immunity (interferon gamma) as the hallmarks of nickel-sensitive patients. Further studies are needed to clarify the major cell phenotype associated with this type 2 immune response and the lack of type 1 immunity observed in nickel-sensitive people.     

Evaluation of scalp hair nickel and chromium level changes in patients with fixed orthodontic appliance: a one-year follow-up study

Background and objectives: The release of metal ions from orthodontic appliances is part of the dissolution and biomechanical processes of alloys. Nickel (Ni) and chromium (Cr) are the elements commonly used in the manufacture of various components of fixed orthodontic appliances, including bands, brackets and wires. This study was aimed to measure the Ni and Cr ions levels in the scalp hair of patients treated with fixed orthodontic appliances in comparison of the control group.

Materials and methods: The patient group consisted of 24 patients treated with fixed orthodontic appliances for one year, while the control group included 28 healthy individuals without orthodontic appliances. Analysis of the Cr and Ni was performed using atomic absorption spectrophotometer by graphite furnace method. The data were analyzed via student and paired samples t-test and ANOVA repeated measurement test.

Results: After one year, the levels of Ni and Cr in two groups showed significant differences (0.086?±?0.007 and 0.258?±?0.009 µg/g for control group and 0.149?±?0.010 and 0.339?±?0.013 µg/g for patient group, respectively for Ni and Cr, p?Conclusion: Due to the slightly elevated levels of Ni and Cr ions in the scalp hair of patients treated with fixed orthodontic appliances and considering the cytotoxic and allergic effects of these ions, changing the ingredients in fixed orthodontic appliances is suggested for the future.     

In vivo study of metal content of oral mucosa cells in patients with and without fixed orthodontic appliances

OBJECTIVE: To compare the concentration of nickel, chromium and cobalt in oral mucosa cells of patients with and without fixed orthodontic appliances. MATERIALS AND METHODS: A total of 60 patients were included in this study. The control group consisted of 30 patients without any type of fixed orthodontic appliances or metal restoration in the mouth (20 females and 10 males from 16 to 20 years with a mean age of 18 years). The test group consisted of 30 patients who had fixed orthodontic appliance in their upper and lower arches (20 females and 10 male from 16 to 20 years with a mean age of 18.2 years). The metal content determinations were carried out using atomic absorption spectrophotometry with a graphite furnace. RESULTS: According to spectrophotometric analysis, no significant differences in chromium (p = 0.09) and cobalt (p = 0.10) content of oral mucosa cells were found between the test and control samples. The nickel content in mucosa samples was significantly higher (p = 0.003) in orthodontic patients compared with the controls. The mean levels of nickel in control and orthodontic patient group were 12.26 and 21.74 ng / ml, respectively. CONCLUSION: Our findings indicate that there was no difference in the concentration of chromium and cobalt in oral mucosa cells of patients with or without fixed appliances. However, a significantly higher concentration of nickel can be found in oral mucosa cells of patients wearing fixed orthodontic appliances. Continued follow-up is needed to determine the long-term significance of nickel release.     

正畸固定矫治器释放镍离子对机体的影响

固定矫治器是正畸患者口内镍的主要来源。近年来,正畸金属材料的腐蚀性和其潜在的毒性正逐渐受到人们的关注。本文就正畸固定矫治器释放的镍离子对机体的影响作一综述。     

Nickel and chromium levels in the saliva and serum of patients with fixed orthodontic appliances

The aim of this study was to evaluate the concentrations of nickel and chromium ions in salivary and serum samples from patients treated with fixed orthodontic appliances. A second aim of this study was to determine any significant changes in these concentrations during any period of the treatment time. Saliva and blood samples were collected from 100 patients ranging in age from 12 to 33 years. Twenty samples from each group were obtained. The groups were as follows: In the first group, saliva and blood samples were collected before insertion of the fixed appliances. In the second, third, fourth, and fifth groups, samples were collected at 1 week, 1 month, 1 year, and 2 years after appliance insertion. The serum was prepared by centrifuging the blood samples at 3000 rpm for 10 minutes. The fixed appliances consisted of an average of 4 bands and 20 bonded brackets. No palatal or lingual appliances welded to bands or extraoral auxiliary appliances were used. The spectrophotometric determinations were carried out using electrothermal atomic absorption spectrophotometry. The results indicated certain differences in the amounts of nickel and chromium released from fixed orthodontic appliances during different periods of treatment. The Mann-Whitney U-test from the SPSS statistics program was used to analyze the significance of the differences between no-appliance samples and those obtained with the appliances present. In the serum, there were statistically significant increases in ion concentration in the second-year groups. In saliva samples, nickel and chromium reached their highest levels in the first month and decreased to their initial level in the rest of the groups. It can be concluded that fixed orthodontic appliances release measurable amount of nickel and chromium when placed in the mouth, but this increase doesn't reach toxic levels for nickel and chromium in the saliva and serum.     

The effect of fixed orthodontic appliances on the oral carriage of Candida species and Enterobacteriaceae

The aim of this investigation was to evaluate the prevalence of Candida and Enterobacteriaceae in a group of adolescents during fixed orthodontic appliance (FOA) therapy. The experimental group was recruited from a larger sample of orthodontic patients who were clinically examined once to obtain baseline data before active treatment. The group comprised 27 subjects; 13 males, 14 females (mean age 15.5 +/- 2.3 years). Thereafter, the experimental group was examined three times during a 3 month follow-up period after insertion of the FOA. The whole mouth plaque score was obtained, and the oral cavity was then sampled for Candida species and Enterobacteriaceae using three different microbiological culture techniques, namely the oral rinse, pooled plaque and the imprint culture.A significant increase in candidal numbers was observed after FOA insertion when the imprint technique was used (P < 0.001), although the overall candidal prevalence rates obtained using the oral rinse and pooled plaque techniques did not demonstrate such a change. The predominant Candida species isolated was C. albicans and the number of coliform carriers significantly increased after the insertion of a FOA, as detected by the oral rinse (P < 0.05) and the pooled plaque (P < 0.05) techniques. In total, eight coliform species were isolated following FOA therapy compared with the three species isolated before insertion of the appliance. The results also revealed a significant increase in plaque index due to the introduction of a FOA. Taken together, these data imply that insertion of a FOA is likely to promote oral carriage of Candida and coliform species. Furthermore, it appears that routine oral hygiene instruction and information on appliance hygiene given to these patients may not necessarily reduce plaque accumulation and possible attendant effects. Further work with a larger cohort is required to confirm these findings.     

An orthodontic tooth brushing technique to enhance oral hygiene in patients wearing fixed orthodontic appliances: A randomized controlled trial

Background

An effective tooth brushing technique is essential in maintaining oral hygiene, especially for patients wearing fixed orthodontic appliances. Traditional tooth brushing techniques are mainly designed for the general population without orthodontic appliances, which may not account for the oral condition of orthodontic patients due to the increased biofilm formation. The aim of this study was to design an orthodontic tooth brushing technique and compare its effectiveness with the traditional modified Bass technique.

Methods

Sixty patients wearing fixed orthodontic appliances were included in this two-arm paralleling randomized controlled trial. Thirty patients were assigned to the modified Bass technique group and 30 patients were assigned to the orthodontic tooth brushing technique group. The orthodontic tooth brushing technique involved a biting motion on the head of toothbrush in order to place the toothbrush bristles behind the archwires and around the brackets. Plaque index (PI) and gingival index (GI) were used to assess oral hygiene. Outcome measurements were taken at baseline and 1 month after the intervention.

Results

The new orthodontic tooth brushing technique significantly reduced PI (average PI reduction = 0.42 ± 0.13), especially in the gingival (0.53 ± 0.15) and interproximal (0.52 ± 0.18) areas (p < 0.05 for all). No significant reduction was found for the GI (p > 0.05 for all).

Conclusion

The new orthodontic tooth brushing technique showed a promising result in reducing PI in patients wearing fixed orthodontic appliances.     

In vivo effects of zoledronic acid on oral mucosal epithelial cells

Oral Diseases (2011) 17 , 291–297 Objective: Osteonecrosis of the jaw is a serious complication of bisphosphonate treatment for which the pathophysiology is unknown. The purpose of this study was to investigate whether in vivo zoledronic acid (ZA) induces alterations in cell proliferation, apoptosis, and matrix metalloproteinases (MMPs) expression in oral mucosal epithelial cells. Methods: One‐year‐old dogs were either untreated (control group) or given high doses of intravenous ZA (ZA group) for 3 months. The doses of ZA were equivalent to those given to cancer patients, yet were administered two times more frequently (every 2 weeks). Mucosal tissues were assessed immunohistochemically for cell proliferation (proliferating cell nuclear antigen, PCNA), matrix metalloproteinase (MMP) expression, and apoptosis (caspase 3 and TUNEL). Results: There were no significant differences between the groups with respect to PCNA, MMP‐2, MMP‐14, and TUNEL positive cells. However, the expression of MMP‐9 was significantly higher in the control group than in the ZA group (P < 0.05), whereas the expression of caspase 3 was significantly lower in the control group than in the ZA group (P < 0.05). Conclusion: These results suggest that high doses of ZA resulted in higher levels of apoptosis and lower levels of MMP‐9 in the oral epithelial cells supporting the idea of bisphosphonate treatment affects the oral mucosa.     

Nickel, chromium and iron levels in the saliva of patients with simulated fixed orthodontic appliances

OBJECTIVE: To assess the in vivo release of nickel, chromium, and iron ions into saliva by different metallic brackets. MATERIALS AND METHODS: Thirty volunteers wore removable appliances with bonded brackets and were divided according to the brand of brackets: group A, 3M/Unitek (AISI 303); group B, American Orthodontics (AISI 316L); and group C, Dentaurum (AISI 316L). The appliances were worn for 60 days, and saliva samples were collected at the following time points: T1, before placement of the appliance; T2, after 10 minutes; T3, 24 hours; T4, 7 days; T5, 30 days; and T6, 60 days after insertion of the removable appliance. Saliva samples were analyzed for nickel, chromium, and iron by atomic absorption spectrophotometry. Statistical analysis was performed by nonparametric tests (Friedman, Mann-Whitney, Kruskal-Wallis). RESULTS: Saliva evaluation revealed a large variation in concentration of these ions between individuals. The results also appeared to indicate an increase in nickel and chromium ions immediately after placement of the appliance (T2), but this was statistically significant only for groups B and C. There was no increase in iron levels. A tendency for increases in nickel and chromium concentrations was verified immediately after placement of the appliance, but these values are probably reduced because of biofilm formation regardless of the bracket used. CONCLUSION: Nickel and chromium ion concentrations increased immediately after placement of the appliance in the mouth for all study groups. There were no significant differences in the nickel, chromium, and iron levels released by the three groups of appliances at all study periods.     

Nickel and chromium levels in the saliva of a Saudi sample treated with fixed orthodontic appliances

AimThe aim of this study was to measure the amount of nickel (Ni) and chromium (Cr) released into the saliva of Saudi patients treated with fixed orthodontic appliances.Materials and methodsNinety salivary samples were collected in a cross-sectional manner. Forty samples were collected from patients (17 males, 23 females) with fixed orthodontic appliances after different periods of orthodontic treatment ranging from the first month and up to 32 months into treatment. The fixed orthodontic appliance consisted of 4 bands, 20 stainless steel brackets, and upper and lower nickel titanium or stainless-steel arch wires. The other 50 samples were collected from people without appliances (24 males, 26 females). Samples were analyzed using Inductive Coupled Plasma/Mass Spectrometry and Inductively Coupled Plasma Optical Emission Spectroscopy to measure Ni and Cr levels, respectively. Student’s t-test was used to compare Ni and Cr levels in the treated and untreated control groups.ResultsThe mean Ni level was 4.197 μg/L in the experimental group and 2.3 μg/L in the control group (p < 0.05). The mean Cr level was 2.9 μg/L in the experimental group and 3.3 μg/L in the control group (p < 0.05).ConclusionFixed orthodontic appliances resulted in a non-toxic increase in salivary levels of Ni, but no change in Cr levels. Duration of orthodontic treatment did not affect Ni and Cr levels in the saliva.