1. Dental caries, residual root and crown: it is as harmful bacteria habitat. Incomplete crown for the oral mucosa caused by mechanical trauma and traumatic ulcers or before the formation of white spots, which in clinical common, if these factors are not promptly removed, chronic ulcers will also lead to cancer.
2. Adverse prosthesis: the human body after the denture tooth loss, if the denture production intolerance, leading to chronic mucosal irritation and ulceration, erosion and damage oral mucosa, so as not suitable for denture adjustments and to timely replacement. Where: the human body with age, more or less have some wear, some people like to eat hard food, tooth wear will be more important, the formation of sharp edges and sharp teeth, tongue and bilateral buccal mucosa of a serious stimulation of damage. Dental restoration materials: repair missing teeth after the denture, the people called "false tooth" because the dentures of different materials, a subsidiary The good effect of root canal treatment of bacteria, some of the materials within a short time a large number of attached bacteria and, in particular, some special bacteria produce, on the oral mucosa has a very strong destructive effect.