The influence of endodontic broken stainless steel instruments on the urinary levels of iron.

Previous studies on the endodontic broken stainless steel instruments have mainly focused on retrieval of specimens. However, the systemic consequences of the retained separated instruments need an investigation. The current study aimed to evaluate the correlation between broken stainless steel instruments inside the root canal space and the urinary level of iron (Fe) in patients. Sixty near-aged and same-gender patients were selected. Thirty patients in the control group had no endodontic treatment in their history, while the other 30 patients in the endodontic group had broken stainless steel instrument. The urine samples were collected in iron-free containers. All specimens were refrigerated for 1 day and then subjected to Fe level measurement by electrothermal atomic absorption spectrometry. Data were analyzed by Kolmogorov-Smirnov and t tests at P < 0.05. The correlation coefficients of age and sex were also evaluated in relation with Fe levels in the urine. The level of Fe did not show any significant increase in the experimental group (P > 0.05). There was a positive correlation between age and Fe levels of endodontic and control groups. However, the joint effects of age and sex on Fe levels were different for the two groups. The presence of broken stainless steel instruments inside the root canal space did not elevate the level of Fe in the urine of patients. However, this value was positively correlated with the patient age.

Correlation between long-term in vivo amalgam restorations and the presence of heavy elements in the dental pulp.

PROJECT: To measure the levels of heavy metals (Hg, Sn) in the dental pulp and blood samples of patients with long-term amalgam restorations. PROCEDURE: 12 amalgam restored and 12 non-restored, sound teeth were chosen and access cavity preparation to the pulp chamber was made. The contents were transferred and dissolved in 5mL of concentrated nitric acid followed by placement in an oven at 180°C for tissue digestion. After cooling the tubes each digested sample was transferred to an atomic absorption system to measure the levels of heavy metals. The blood samples of five patients in each group were randomly analyzed to determine the levels of these heavy metals in the blood and if there were a correlation between these levels in blood and pulp. Data were analyzed by t-test at a P<0.05 level of significance. RESULTS: No significant difference was seen between the levels of Hg and Sn in pulp tissues (P>0.05); however, the blood analysis showed higher level of Hg amalgam group (P=0.009). The analysis between the pulp and blood samples showed positive correlations for both Hg and Sn elements in dental pulp and the blood (P=1.000) (P=0.900). CONCLUSIONS: The long-term presence of dental amalgam (at least 5 years) did not result in any remarkable changes in the levels of mercury and tin in the pulp tissue; however, there were increases in the level of mercury in the blood circulation even five years following the placement of the restoration.