Are grape juices more erosive than orange juices?

AIMS: To evaluate the chemical characteristics of grape and orange juices, and their erosive potential in the decrease of microhardness and the loss of enamel structure. METHODS: Five grape and orange juices were evaluated for pH, titratable acidity, calcium, phosphate, and fluoride concentration. De-ionised water and Cola soft drink were used as a negative and positive control, respectively. Twelve specimens of bovine enamel were immersed in beverages for 10 min at 37 °C, 3 times/day for 7 days. Erosive potential was quantified using microhardness and loss of enamel structure. Anova One Way, Student's t test, Multiple Regression and Spearman Correlation (p < 0.05) were used to analyse the results. RESULTS: Powdered grape juice showed the lowest pH (3.18 ± 0.03) and pure grape juice presented the highest titratable acidity (5.48 ± 0.06 mL NaOH/100 mL). Fresh orange juice and soya-based grape juice revealed the lowest calcium (0.77 ± 0.12 mmol/L) and phosphate concentrations (0.35 ± 0.06 mmol/L), respectively. Among juices, powdered orange juice caused the greatest decrease in surface microhardness (SMH) (127.99 ± 40.47 ΔSMH) and grape juice from concentrate caused the greatest loss of enamel structure (13.30 ± 3.56 µm). CONCLUSIONS: All of the evaluated juices contributed to dental erosion. Grape juices presented greater erosive potential than orange juices. Pure, powdered and concentrated grape juices showed similar loss of enamel structure to the Cola soft drink. The erosive potential of beverages was statistically correlated to pH, titratable acidity, calcium, phosphate and fluoride concentrations.

Electronic determination of root canal working length in primary molar teeth: an in vivo and ex vivo study.

AIM: To evaluate in vivo and ex vivo the accuracy of an electronic apex locator in primary molar teeth with or without root resorption. METHODOLOGY: Fifteen primary molar teeth with 30 root canals were divided into two groups: roots without resorption (n = 13) and roots with resorption (n = 17). Root canals were measured with the Root ZX apex locator in vivo, and then after tooth extraction, each canal was measured electronically ex vivo. The actual root canal length was measured visually, with the placement of a K-file into the most cervical edge of either apical foramen or resorption. The Student's t-test was applied for statistical analysis at a 5% significance level. RESULTS: The electronic apex locator was precise in 69% and 65% of the cases with and without root resorption, respectively (tolerance = ± 0.5 mm), in vivo and 69% and 77%ex vivo. When the tolerance was ± 1 mm, however, these figures increased to 92% and 94% for root canals with and without resorption, respectively, in vivo and ex vivo. No significant difference was observed between the resorbed and non-resorbed root canals measured using the Root ZX. CONCLUSION: The Root ZX apex locator was accurate in determining in vivo and ex vivo the working length ± 1 mm in primary molar teeth in over 90% of roots regardless of the presence of root resorption.