Let’s draw an analogy between teeth and houses. As everyone knows, when you want to renovate a big house, like a bungalow, you will require a lot more effort and material as compared to an apartment. As a result, one can guess that it would also cost more to renovate the bungalow.
With that said, it is also more time consuming and labour intensive to treat a more complex tooth. For example, molar as it can have twice, thrice, 4 times or even 5 times as many root canals as a premolar or front tooth. Hence, the fees will also be higher.