Back-polymerization of photopolymers with application in e.g. dental fillings, occurs at interface opposite entry point, where coating converts incident radiation to new wavelengths initiating setting

摘要

The polymer is irradiated by an electromagnetic wave. Its spectral band is unsuitable to initiate polymerization. Only following a change in wavelength resulting from incidence of the beam on the side of the polymer opposite the location of beam entry, is polymerization initiated. An Independent claim is included for corresponding equipment. Preferred features: Contact surfaces are treated before coating the polymer, to emit waves exciting polymerization. Radiation emitted from the far side (opposite the entry point) is employed for photopolymerization. Reversal of directed polymerization shrinkage prevents formation of edge gaps or internal stressing due to polymerization. After-flow compensates polymerization shrinkage, with the same benefits. Photoinitiators used in the polymer are matched or co-ordinated with substances on the contact surfaces, used to shift the wavelength. Before coating the contact surfaces with polymer, they are treated with substances emitting at wavelength exceeding excitation wavelength, in accordance with Stokes rule. Radiation-emitting substances at contact surfaces, function as bonding agents between polymer and adjacent materials. Radiation emission at contact surfaces serves for optical marking of boundaries between polymer and bordering materials.