Journal of Dental Medicine

Background and Aim: Lead is one of the most dangerous metallic poisons which can lead to acute and chronic poisoning with a broad range of systemic and oral signs. The aim of this study was to evaluate the relationship between the prevalence of oral complications and blood lead level in workers employed in Koushk lead mines, Yazd province.

Materials and Methods: This analytical study was conducted on 70 subjects employed in Koushk lead mines and 70 workers in Yazdbaf textile factory as control group. A questionnaire including demographic information and medical questions was completed for each case and oral manifestations were recorded, as well. Blood samples were taken from subjects and blood lead level was measured by atomic absorption spectrophotometer. Data were analyzed using t, Chi-Square and Mann Whitney tests with p<0.05 as the limit of significance.

Results: The mean lead level was 7.06 µg/dl in case group and 4.97µg/dl in control group (P= 0.039). In case group, 3 subjects had blood lead level more than 20µg/dl. Statistical analysis showed significant differences regarding neurologic disorder, chronic fatigue, existence of lead line, mucous pigmentation, gingivitis, tongue burning, taste sense reduction and DMF between case and control groups (P<0.05).

Conclusion: Based on the results of this study, since the mean blood lead level in mine workers was in normal limits, the observed symptoms were not related to systemic poisoning. Direct contact of the oral mucosa with the lead in breathing air or other factors related to overall health problems in mine workers may be responsible for the present findings. Further studies are recommended on similar subjects working in different conditions.

  Background and Aims: In case of nonsurgical endodontic re-treatment or replacing a restoration, one of the best methods for removing post from the canal is using an ultrasonic vibration. The aim of this study was to evaluate the effect of ultrasonic vibration time on the retention of post luted with zinc phosphate or glass ionmer cements.

  Materials and Methods: 96 sound extracted lower premolars were selected. The coronal section of specimen was removed and the roots were endodontically treated. A 9-mm post space was prepared in each specimens and a stainless steel Parapost XP was cemented into the post space. Half of the specimens were cemented with the Zinc phosphate cement and the other by g lass ionomer cement. After 7 days of storage, both groups were equally divided into 4 subgroups of 12 teeth. Control group did not receive any treatment. The other subgroups subjected to ultrasonic vibration for 4, 8 or 12 minutes. The retention of all specimens was evaluated and data were analyzed using ANOVA and Tukey tests.

  Results: In control (no ultrasonic) group and 4 minute ultrasonic group, the retention of posts luted with Zinc phosphate cement were not significantly differen t from those luted with g lass ionomer cement. (P=0.372). On the other hand , applying of ultrasonic vibration for 8 and 12 minutes in zinc phosphate and 12 minutes in g lass ionomer caused a significant reduction in the retention of posts (P=0.01).

  Conclusion: Although, the initial retention of two cements was not different, the ultrasonic vibration had more catastrophic effect on zinc phosphate in comparison to glass ionomer.