Material testing
Biocompatibility testing was completed as recommended by ISO 10993. The sterilized
implant was subjected to and passed the following tests: cytotoxicity,
intracutaneous reactivity, material mediated pyrogen, USP physiochemical tests for
plastics, acute systemic toxicity, chronic toxicity, sensitization testing, and mutagenicity
testing. For more detailed information of the implant material, please see
"Polyethylene Terephthalate and the Pillar Palatal Implant: Its Historical Usage and Durability in Medical Applications".
Testing was also conducted to evaluate tissue response to the implants, which are designed to take advantage of the body's natural response to a foreign object by: stimulating tissue ingrowth into each implant; forming a fibrous capsule around each implant; and, generating fibrous cross-linking between the implants. This fibrotic response causes the tissue around the implants to become stiffer than the original tissue, effectively reducing both the flutter that can cause snoring and the ability of the soft palate to obstruct the upper airway. Histological results confirmed that the implants should be placed as close as possible without touching to achieve maximum stiffening. An implant should be no more than 2 mm away from an adjacent implant in order to achieve the fibrotic responses that contribute to lateral stiffening, effectively making a bridge of stiffer tissue between the implants.
A representative illustration of a palatal cross-section is shown below to illustrate the tissue composition of the soft palate and fibrotic response to Pillar implants.
Fibrotic response to Pillar implants.
The largest muscle mass is found along the midline of the palate (muscle uvulae). The maximum
fibrotic response is achieved when the implants are placed into the muscle of the soft palate. In
glandular tissue, the fibrotic capsule is very thin and doesn't stiffen the surrounding tissue as
effectively.
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