RESUMO
The regenerating digit tip of mice is a novel epimorphic response in mammals that is similar to fingertip regeneration in humans. Both display restricted regenerative capabilities that are amputation-level dependent. Using this endogenous regeneration model in neonatal mice, we have found that noggin treatment inhibits regeneration, thus suggesting a bone morphogenetic protein (BMP) requirement. Using non-regenerating amputation wounds, we show that BMP7 or BMP2 can induce a regenerative response. BMP-induced regeneration involves the formation of a mammalian digit blastema. Unlike the endogenous regeneration response that involves redifferentiation by direct ossification (evolved regeneration), the BMP-induced response involves endochondral ossification (redevelopment). Our evidence suggests that BMP treatment triggers a reprogramming event that re-initiates digit tip development at the amputation wound. These studies demonstrate for the first time that the postnatal mammalian digit has latent regenerative capabilities that can be induced by growth factor treatment.
Assuntos
Proteínas Morfogenéticas Ósseas/fisiologia , Regeneração/fisiologia , Cotos de Amputação/fisiopatologia , Animais , Animais Recém-Nascidos , Sequência de Bases , Proteína Morfogenética Óssea 2/farmacologia , Proteína Morfogenética Óssea 7/farmacologia , Proteínas Morfogenéticas Ósseas/genética , Regeneração Óssea/efeitos dos fármacos , Regeneração Óssea/genética , Regeneração Óssea/fisiologia , Primers do DNA/genética , Extremidades/fisiologia , Humanos , Hibridização In Situ , Camundongos , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Osteogênese/fisiologia , Proteínas Recombinantes/farmacologia , Regeneração/efeitos dos fármacos , Regeneração/genética , Transdução de SinaisRESUMO
PURPOSE: The purpose of this study was to formulate and characterize experimental antibacterial fluoride-releasing sealants and compare them with commercial sealants for fluoride release, recharge, adhesion, and microleakage. METHODS: Two experimental sealants (Exp-1, Exp-2) containing a synthesized antibacterial fluoride-releasing monomer and fluoride-releasing filler were formulated. Exp-2 also contained NovaMin nanoparticles. Commercial sealants Clinpro (CL) FluroShield (FS), and SeLECT Defense (E34) were also included. Fluoride release from disk samples in deionized water was measured daily using an ion-selective electrode for 14 days, and after recharging with Neutra-Foam (2.0% sodium fluoride), fluoride was measured for 5 days. Microtensile bonding strengths (MTBS) to enamel were tested after 24-hour storage in water at 37°C or thermocycling 5-55°C for 1,000 cycles. A microleakage test was conducted on extracted teeth using a dye-penetration method. The data were analyzed using analysis of variance with the Tukey's honestly significant difference test and Kruskal-Wallis test. RESULTS: Exp-1 and Exp-2 had significantly higher fluoride release and recharge capabilities than CL and FL (P<.05). All tested sealants had similar MTBS before and after thermocycling. Exp-2 and Exp-1 had significantly lower microleakage scores (P<.05) than other groups. CONCLUSION: The experimental sealants had higher fluoride release and recharge capabilities and similar or better retention than commercial sealants.