The teeth are actually made of bone. Adult tuataras also enjoy young tuatara - in a culinary sense. The female buries up to 19 soft shell eggs in soil, but not often. Life is slow in the cold blooded reptile world and egg laying occurs about once per 4 years. Even laying in soft soil is a contested activity, for other females may dig up the eggs to lay their own.
Males can mate every year.
Females taking 4 years is a bit frustrating for them. So males fight vigorously over receptive females, and often show combat scars. The juveniles mature slowly over 9 to 13 years, and Tuataras live for 60 to 100 years. The sex of Tuataras is decided by soil temperature around the eggs. Warm soil causes males, cool soil leads to females.