 Which he made into a toothbrushwhich gave him the idea to mass produce it on the outside under the name Wisdom Toothbrushes.
<clarity>  Which he made into a toothbrushwhich gave him the idea to mass produce it on the outside under the name Wisdom Toothbrushes.
 Which he made into a toothbrushwhich gave him the idea to later mass-produce toothbrushes under the name Wisdom Toothbrushes.