Mineral Trioxide Aggregate and Diluted Formocresol Pulpotomy: Prospective and Retrospective Study Outcomes.

Mineral Trioxide Aggregate (MTA) has been used in many endodontic procedures with success. We hypothesized that MTA as a pulpotomy medicament elicits outcomes no different than that of the diluted formocresol (DFC). PURPOSE: The purpose of this study was to compare the outcomes of grey MTA and DFC in primary molar pulpotomies at a teaching institution and a pediatric dental practice. METHODS: At the teaching institution, 206 primary molars of 122 children were enrolled. At 48-months, 20 teeth treated with MTA and 25 teeth treated with DFC, were available for evaluation. At the private practice, dental records of 245 primary molars of 68 patients were available for evaluation. RESULTS: At 48 months, the results from both sites showed a radiographic success rate of 80 percent for DFC and 95 percent for MTA. The odds of radiographic failure were not affected by study sites. The Cox-regression analysis revealed that patient's age at the time of pulpotomy impacted the "hazard of exfoliation." Each year following the completion of DFC or MTA pulpotomy, there is a 4.6-times-more-likely chance for early exfoliation of the pulpotomized tooth. CONCLUSION: Grey MTA is an acceptable alternative for primary molar pulpotomies.

Pyriform spidroin 1, a novel member of the silk gene family that anchors dragline silk fibers in attachment discs of the black widow spider, Latrodectus hesperus.

Spiders spin high performance threads that have diverse mechanical properties for specific biological applications. To better understand the molecular mechanism by which spiders anchor their threads to a solid support, we solubilized the attachment discs from black widow spiders and performed in-solution tryptic digests followed by MS/MS analysis to identify novel peptides derived from glue silks. Combining matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry and cDNA library screening, we isolated a novel member of the silk gene family called pysp1 and demonstrate that its protein product is assembled into the attachment disc silks. Alignment of the PySp1 amino acid sequence to other fibroins revealed conservation in the non-repetitive C-terminal region of the silk family. MS/MS analysis also confirmed the presence of MaSp1 and MaSp2, two important components of dragline silks, anchored within the attachment disc materials. Characterization of the ultrastructure of attachment discs using scanning electron microscopy studies support the localization of PySp1 to small diameter fibers embedded in a glue-like cement, which network with large diameter dragline silk threads, producing a strong, adhesive material. Consistent with elevated PySp1 mRNA levels detected in the pyriform gland, MS analysis of the luminal contents extracted from the pyriform gland after tryptic digestion support the assertion that PySp1 represents one of the major constituents manufactured in the pyriform gland. Taken together, our data demonstrate that PySp1 is spun into attachment disc silks to help affix dragline fibers to substrates, a critical function during spider web construction for prey capture and locomotion.