There are many owner misconceptions and misinformation on the internet about what does or does not help with preventing dental disease in rabbits. Many owners can be quite shocked when they learn the truth!
The basics of dental disease always come back to diet. Rabbits require a diet that is at least 80% high quality grass hay (oaten, meadow, or timothy), 5% concentrates such as a plain pellet without any muesli or seeds, 5% healthy treats such as apple, banana, or Oxbow Simple Rewards, and 10% fresh green vegetables such as Chinese vegetables, kale, and pot herbs. This comes out to a large double handful of hay a day (about the same size as the rabbit), a head of bok choy or the equivalent in other vegetables, a slice of apple or banana, and a tablespoon of pellets.
The reason why hay is so important is that eating hay produces the lengthy, lateral grinding that is required to keep the crowns of the cheek teeth in correct wear. Chewing on wood blocks or other chew toys that are marketed does not actually improve the wear of cheek teeth. The incisors wear down by contacting each other during biting, and incisor malocclusions are often due to congenital or trauma-related misalignment, reducing or eliminating the natural wear between the maxillary and mandibular incisors.
Rabbits that are not used to eating hay and more used to eating palatable but unhealthy concentrates and muesli can be coerced into eating hay by increasing the palatability of the hay. At home methods include spraying the hay with apple juice or other sweet items as a temporary measure until hay eating becomes a habit, soaking the hay in warm water to increase the moisture content, or mixing dried banana chips or cranberries into the hay to get the rabbit to search through and eat some hay on the way. Oxbow also produces flavored hays that can be a good way to start off a reluctant rabbit.