PubMed · 8524514
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E Isaac. 1995. New guidelines.. https://pubmed.ncbi.nlm.nih.gov/8524514/
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A simple two-step chemical treatment, i.e. etching with HCl and H2SO4 followed by immersion in boiling dilute NaOH solution, has been developed by our group to prepare bioactive microporous titanium surfaces allowing fast deposition of a calcium phosphate layer (CPL) from an in vitro supersaturated calcification solution (SCS). In this work, a precalcification (Pre-Ca) procedure was applied by soaking the two-step treated titanium in Na2HPO4 and then saturated Ca(OH)2 solution before immersion in SCS to accelerate further the CPL precipitation. The treated titanium surfaces with Pre-Ca were characterized after 1, 2, 4, 8 and 16 h of immersion in SCS by means of scanning electron microscopy together with energy dispersive X-ray analysis, X-ray diffraction and infrared absorption analysis. It was observed that the CPL precipitation rate with Pre-Ca averaged 1 microm h-1, twice as fast as without Pre-Ca. No precipitation was observed on untreated titanium with Pre-Ca up to day 14 of immersion in the SCS.
Lipopolysaccharide (LPS), a cell wall component of Gram negative anaerobic bacteria, has been implicated in the pathogenesis of periapical disease resulting from infected root canals. Calcium hydroxide [Ca(OH)2] has been shown to be an effective medicament in such infections, reducing the microbial titre within the canal. It has been proposed that the therapeutic effect of Ca(OH)2 may also be the result of direct inactivation of LPS. The aim of this study was to investigate whether the toxic potential of an Escherichia coli LPS could be reduced or eliminated by Ca(OH)2. Four concentrations of E. coli LPS ranging from 1-1000 ng/ml sterile water were incubated in duplicate either with 25 mg Ca(OH)2 or sterile water alone. Controls consisted of Ca(OH)2 without LPS or sterile water only. Monocytes were collected from peripheral blood by centrifuging through a gradient and plated to a specific density. Adherent monocytes were incubated for 4 days at 37 degrees C with 5% CO2 in M199 medium with 10% autologous serum. The different LPS solutions were added to the wells on day 5. After 4 h the supernatants were collected and quantitatively assayed for TNF-alpha using a commercial ELISA kit. Statistical analysis was performed with ANOVA. Results indicated that Ca(OH)2 is able to eliminate the ability of an E. coli LPS to stimulate TNF-alpha production in peripheral blood monocytes (P < 0.0001).
A quantitative longitudinal study was carried out to compare the amount of microleakage using two different types of root canal sealers on straight and curved root canals. Microleakage was measured just after the setting of the sealer, one month and three months after that using fluid transport model. One month follow up results showed that in straight root canals both the ZOE containing Pulp Canal Sealer and the calciumhydroxide containing Sealapex sealers produced similar microleakage values to that values measured just after the setting of materials. One month follow up measurement resulted higher values in curved canals comparing to the straight ones in case of both the tested materials. Three months follow up measurement demonstrated worse results in the Sealapex groups than the Pulp Canal Sealer groups. With loglinear statistical analysis the following interactions were proved between variables: root canal form/microleakage, root canal form/time laps, and material/microleakage/time laps. Results of the present study are in good agreement with conclusions of recently published other studies, namely calciumhydroxide containing sealers resulted in higher microleakages than ZOE containing sealers.