Oral restorations for the treatment of diseases provide great convenience to patients, but if the selection of oral restorations, the selection of materials is not appropriate, it is easy to cause greater distress to patients, this is harmful to dental disease without benefit of inappropriate oral restorations are known as bad restorations. These bad restorations will not show potential harm in the short term, but over time, they will have different degrees of impact on the patient, mainly in the following ways: 1, affecting the aesthetics: the color and shape of bad restorations and natural teeth are poorly coordinated. Even some bad restorations are made of self-consolidating plastic, which is easily discolored or colored, making the dentures yellow and black, which extremely affects the beauty. 2.Tooth decay: Some bad restorations are made of low quality materials, and due to the inferior materials, gaps are often formed between the fillings and the healthy neighboring teeth, and it is difficult to clean thoroughly when brushing, so that bacteria can attach and grow to form cavities, and the originally healthy teeth will be damaged. 3, gum inflammation: The edge or surface of bad restoration is generally very rough and badly shaped, which will make bacteria easily accumulate in the periodontium, tartar accumulation, stimulate the gum, and easily cause chronic inflammation of the gum. The main symptoms are bleeding gums, swelling, bad taste in the mouth, and weakness in chewing. Special attention is paid to the long-term stimulation of oral tissue by bad restorations may also cause cancer of oral mucosa tissue. 4, temporomandibular joint disorder symptoms: due to the poor bite relationship of bad restorations is poor. And the oral cavity in a long-term unbalanced bite state, will cause the temporomandibular joint popping, pain and other symptoms. 5, psychological impact: bad restorations bring discomfort to the patient will reject or fear restorative treatment teeth.