In vitro cleaning potential of waist-shaped interdental brushes

There are many interdental cleaning aids available for patient use, including toothpicks, dental floss and interdental brushes (IDBs). Most are available in various shapes and sizes. The aim of this laboratory study was to evaluate and compare the cleaning efficacy of waist-shaped interdental brushes to those of cylindrical shape. Four groups of IDBs, ranging in diameter from 2 mm to 9 mm, were tested. To reduce production and material bias, all brushes tested were from the same manufacturer. Cleaning efficacy was tested on two different devices: 1) a geometrical model, using opposing rectangular blocks at separation distances of 1 mm to 4 mm and 2) an anatomical model, displaying a standardized maxillary segment from canine to 3rd molar. The surfaces in both devices were coated with a titanium oxide slurry, then cleaned under standardized conditions and planimetrically evaluated. The measurements took place after 1, 5 and 10 cleaning strokes, respectively. Both models showed significant superiority in the cleaning efficacy of the waistshaped brush (p < 0.001), at 1, 5 and 10 strokes. Based on the present results, it can be concluded that interdental brushes with a waistshaped form showed cleaning potential superior to their cylindrical-shaped counterparts, under standardized laboratory conditions.

Enterococcus faecalis type strain leakage through root canals filled with Gutta-Percha/AH plus or Resilon/Epiphany.

The aim of this in vitro study was to compare leakage of Enterococcus faecalis ATCC 29212 through root canals of single-rooted extracted human mandibular premolars filled with either gutta-percha/AH Plus or Resilon/Epiphany using the continuous wave of condensation technique. Test and control teeth were suspended in an experimental bacterial leakage setup for 50 days. Kaplan-Meyer curves showed a tendency of the gutta-percha/AH Plus root fillings to prevent leakage better than Resilon/Epiphany counterparts. This tendency, however, was not statistically significant (log-rank test, p = 0.141). The estimated mean time for turbidity to occur in the broth below the suspended root was 35 days (SD = 5 days) in the gutta-percha/AH Plus and 33 days (SD = 4 days) in the Resilon/Epiphany group. It was concluded that within the limitations of this study, there was no apparent advantage of using Resilon/Epiphany over gutta-percha/AH Plus.

Effects of 1alpha,25-dihydroxy-vitamin D3 pretreatment and MAP kinase inhibitor PD 98059 on response of osteoblasts to prostate-derived osteoblastic factors.

Prostate carcinoma-derived factors induce a proliferative response in osteoblasts. The present study investigated the involvement of MAP kinase in the osteoblastic reaction of osteocytes and the response of 1alpha,25-hydroxy-vitamin D3 (1,25-vitD3)-pretreated osteoblasts. Conditioned media (CM) from prostate, colon, pancreatic, renal cell and breast cancer cell lines were tested on their proliferative activity using murine osteoblast-like MC3T3-E1 cells, MG63 human osteosarcoma cells and immortalized human osteoblasts (AHTO-7). Changes in osteoblastic activities of the supernantants were measured in the presence of MAP kinase inhibitors and following 1,25-vitD3-induced differentiation of the target osteoblasts. Supernatants of prostate cancer cells stimulated proliferation of osteoblasts in all three indicator cell lines, with AHTO-7 exhibiting the most significant correlation to human primary osteoblast cultures. 1,25-vitD3 induced the differentiation marker alkaline phosphatase (ALP) in MC3T3-E1 and AHTO-7, but only to a minor degree in MG63 cells. 1,25-vitD3-induced differentiation reduced the proliferative response to CM from several cell lines in MC3T3-E1 and MG63 to a minor degree, whereas in AHTO-7 cells the osteoblastic reaction was reduced for 2/4 pancreatic, 3/3 colon and 1/1 renal cancer CMs, however not for 3/3 prostate cancer CMs. Stimulation of AHTO-7 cells by CM from prostate cancer lines is inhibited significantly by MEK1 kinase inhibitor PD 98059 in contrast to CMs derived from other carcinomas, except ACHN renal cancer cells. The findings in the present study demonstrate that human AHTO-7 cells seem to represent a valid human system to monitor osteoblastic activity, especially in respect to 1,25-vitD3-induced differentiation. Vitamin D3-induced differentiation has no direct effect on prostate cancer-derived osteoblastic activity in the same cell line in vitro, which however, could be reversed by disruption of the signal transduction at the MAP kinase level, revealing a new target for the inhibition of prostate cancer-associated bone formation.

In Vitro Evaluation of Oxoplatin: An Oral Platinum(IV) Anticancer Agent.

Platinum(IV) compounds like oxoplatin (cis, cis, trans-diammine-dichlorido-dihydroxido-platinum(IV)) show increased stability and therefore can be applied orally. In a panel of 38 human cancer cell lines this drug induced S-phase arrest and cell death with IC(50) values 2.5-fold higher than cisplatin. Oxoplatin may be converted to cisplatin by intracellular reducing agents, however, exposure to 0.1 M HCl mimicking gastric acid yielded cis-diammine-tetrachlorido-platinum(IV) exhibiting twofold increased activity. Similar results were obtained for another platinum(IV) compound, JM 149 (ammine-dichlorido-(cyclohexylamine)-dihydroxido-platinum(IV)), but not for its parent drug JM 216/satraplatin. Genome-wide expression profiling of H526 small cell lung cancer cells treated with these platinum species revealed clear differences in the expression pattern of affected genes between oxoplatin and cisplatin. In conclusion, oxoplatin constitutes a potent oral agent that is either reduced or converted to distinct active compounds, for example, by gastric acid or acidic areas prevailing in solid tumors, in dependence of the respective pharmaceutical formulation.

Prevention of bacterial leakage through instrumented root canals by bioactive glass S53P4 and calcium hydroxide suspensions in vitro.

OBJECTIVE: The capacities of bioactive glass S53P4 and calcium hydroxide suspensions to prevent microbial leakage through instrumented root canals were compared. STUDY DESIGN: Root canals of caries-free extracted human mandibular premolars were instrumented and randomly filled with calcium hydroxide or S53P4 (n = 14 each). Crowns were exposed to Enterococcus faecalis ATCC 29212 suspensions in a test setup with 2 broth chambers, and leakage was checked daily. Event times were compared using log rank test. After 50 days, teeth were fractured and inspected in a scanning electron microscope (SEM). RESULTS: Calcium hydroxide prevented leakage significantly better than S53P4 (P < .05). Estimated mean days to leakage were 26 for calcium hydroxide and 4 days for S53P4. The SEM observations revealed substantial calcification of the glass material in the root canal but also gaps containing clusters of coccoidal bacteria. CONCLUSION: The bioactive glass material under investigation could not prevent contamination of instrumented root canals.