Please explain why is having an overbite bad?

Malfunction: Whether it'a a deep vertical overbite or a large horizontal (buck tooth) overbite (overjet), it means that teeth are not meeting properly and therefore functioning incorrectly. Results can be excessive tooth wear, chipped teeth, damage to supporting bone/gums, and damage to jaw joint. Please see a qualified orthodontic specialist for evaluation and treatment recommendations.

Disadvantages of OB: Most overbites are not considered serious. However, there are certain cases in which the OB patient will have disadvantages like jaw pain, tooth decay and gum disease. Talk to your dentist or orthodontist about corrective options.