It was quite a surprise to discover that the word "teach" appears nowhere in the Shema. I had been raised to translate v'shinnantam l'vanecha as "and you shall teach them to your children", so it was a little perturbing to find out that the Hebrew root of the word v'shinnantam was shen, relating to teeth, rather than education.
The commentators deliberate over this image of teeth in the context of education. Both Rashi and Rashbam like the idea of focusing and shaping a student's mind, so that, like a sharpened tooth, they can ask incisive questions without chewing things over. Others, like Bekhor Shor, are taken with the idea of repeating and driving home the values of the Torah. They believe that just as a bite with sharp teeth makes a mark, so the concerted process of conveying these teachings leaves a lasting impression.

Another approach might be to "indent" the sentiments of the Shema upon a Jewish child's psyche, so that their identity becomes synonymous with the values of the Shema, and with Judaism as a whole. As an educator, I have witnessed the erosion of old-fashioned approaches to education, such as chalk and talk, or learning by rote. Modern Jewish children, who often know more about selfies than selflessness, will only gain a lasting impression of Judaism if, time and again, they are shown its contemporary relevance. This does not need to be terribly elaborate, just something memorable which creatively connects classic Jewish values with current ethical dilemmas; thereby bringing ancient Jewish teachings to solve modern-day scenarios.

If we reduce the Shema to nothing more than a routine mantra said on rising and going to bed, not so different from brushing one's teeth, then it will never leave a lasting impression upon our Jewish future.