Toothbrush head with means to direct and collect radiation

A toothbrush head having a bristle surface from which a cluster of bristles extends in a bristle direction, the head comprising means to direct incident radiation toward a surface of a tooth and means to collect emitted radiation from the surface of the tooth, wherein;

• the means to direct incident radiation toward the surface of a tooth, or the means to collect emitted radiation from the surface of the tooth comprise one or more core within the toothbrush head made of a first plastic material which is transparent to the incident or emitted radiation, and in which radiation transmitted internally within the core is guided by internal reflection within the core, the first plastic material having a refractive index N1, and a first sheath surrounding the core and comprising a monolithic body in which the bristles of the head are mounted, and which is made of a second plastic material which is transparent to the incident or emitted radiation, the second plastic material having a refractive index N2, N1 being greater than N2, such that internal reflection occurs as a result of the difference in refractive index between N1 and N2, or wherein the core is optionally surrounded by a second sheath which is of a reflective material which reflects the incident or emitted radiation.