The best number of teeth for cutting plastic depends on the thickness and type of plastic. For thin plastic, a blade with 60 to 80 teeth works well. Thicker plastic might require a blade with fewer teeth, around 40 to 60. The key is to have enough teeth to create a smooth cut without melting the plastic. Too few teeth can create rough edges, while too many teeth can generate excessive heat. It's also important to use a blade specifically designed for cutting plastic, as it will have specially designed teeth to prevent melting and binding. Ultimately, testing different blade options and consulting manufacturer recommendations can help determine the best number of teeth for a particular plastic cutting project.