Peracetic acid: a practical agent for sterilizing heat-labile polymeric tissue-engineering scaffolds.

Advanced biomaterials and sophisticated processing technologies aim at fabricating tissue-engineering scaffolds that can predictably interact within a biological environment at the cellular level. Sterilization of such scaffolds is at the core of patient safety and is an important regulatory issue that needs to be addressed before clinical translation. In addition, it is crucial that meticulously engineered micro- and nano- structures are preserved after sterilization. Conventional sterilization methods involving heat, steam, and radiation are not compatible with engineered polymeric systems because of scaffold degradation and loss of architecture. Using electrospun scaffolds made from polycaprolactone, a low melting polymer, and employing spores of Bacillus atrophaeus as biological indicators, we compared ethylene oxide, autoclaving and 80% ethanol to a known chemical sterilant, peracetic acid (PAA), for their ability to sterilize as well as their effects on scaffold properties. PAA diluted in 20% ethanol to 1000 ppm or above sterilized electrospun scaffolds in 15 min at room temperature while maintaining nano-architecture and mechanical properties. Scaffolds treated with PAA at 5000 ppm were rendered hydrophilic, with contact angles reduced to 0°. Therefore, PAA can provide economical, rapid, and effective sterilization of heat-sensitive polymeric electrospun scaffolds that are used in tissue engineering.

Localized juvenile spongiotic gingival hyperplasia: a report of 3 cases.

Localized juvenile spongiotic gingival hyperplasia (LJSGH) is a recently described benign condition that affects the gingiva of children and young adults. Clinically distinctive, LJSGH presents as a localized area of erythema on the attached gingiva, with a subtly papillary surface architecture. The lesions are generally biopsied because of the lack of resolution with conservative oral hygiene therapeutic measures and esthetic concerns. The histopathology has a characteristic appearance of subtle papillary epithelial hyperplasia, acute inflammation, and numerous engorged capillary vascular spaces in the lamina propria, although clinical correlation is necessary to make the diagnosis. The purposes of this paper were to: introduce localized juvenile spongiotic gingival hyperplasia to the pediatric dental community; document its clinical and histologic features and treatment and the follow-up of three cases; and discuss the most common clinical differential diagnoses.