Hello mate, this hole in the tooth is called as cavities. So whether you need a filling of rct depend on how deep is the cavity. Tooth consists of 3 layers, outer most hardest layer enamel, second layer ie softer than the first layer called as dentin and inner most layer is pulp or the nerves. so if the cavity is in enamel or dentin and you dont have any pain or sensitivity then filling should be fine if it is deep in or close to the nerve then you have to go for rct. But don't worry visit your dentist, your dentist will do some clinical examination might take help of x ray to determine the depth of the cavity and will advise you the best treatment for your condition

If your tooth has a hole but it isn't paining u so more chances of filling... if the cavity or the hole is giving u trouble like sensitivity to hot nd paining u then u have to get RCT done.... but do attend to ur teeth.... it needs to b filled.... dnt ignore