Variable Tension Dental Floss Holder

I have a working prototype of a transverse dental floss holder with a thumb-operated mechanism to tighten floss for insertion between teeth and slacken it for cleaning them. Key requirements: - Material: Plastic - Compatibility: Both waxed and unwaxed floss - Tension variation: Push button mechanism, preferably tightening floss by more than 10mm achieved by prototype - Ease of threading floss through the mechanism, which may require hinged case Ideal skills and experience: - Experience with plastic molding or fabrication - Familiarity with dental care tools - Mechanism design expertise, especially push-button systems