Compared to a traditional denture, an implant denture features in a better mastication, smaller barrier to linguistic function and doing little harm to the adjacent natural teeth. It is the best among all the dentures, which is believed to be the mainstream in the near future. However, various factors may result in a failed restoration of implant denture. In general, the failure can be embodied in the following aspects.

1. Broken implant abutment

In this case, the abutment together with the prosthesis has separated from the dental implant, leaving a broken end. By observing the X-ray film, we can find that part of the abutment is still trapped inside the dental implant.

2. Loose implant abutment

In this case, the prosthesis hasn't separated from the implant yet, but it has got loose. By observing the X-ray film, we can find a gap existing at where the abutment and dental implant meet.

3. Peripheral Periodontitis

In this case, the dental implant denture hasn't got loose, but there is an edema, congestion and secretion of the surrounding gingiva. By observing the X-ray film, we can find that the bone absorption around the dental implant is larger than 2 millimeters. When it comes to its possible reasons for the failure, we have analysis as follow.

Firstly, the design of the dental implant. An implant is placed into the alveolar bone where there is no teeth, with a main purpose to support the prosthesis in dealing with a masticatory pressure, and transferring it to the jawbone. However, the resultant pressure that the implant denture needs to endure include not only the pressure transferring vertically along with the dental implant, but also pressure that comes horizontally and laterally. What's more, the horizontal pressure is apt to concentrate on the weakest part of the dental implant. As is showed in some studies, pressure on the prosthesis are concentrated on the joint which connects and fixes the abutment with the dental implant. Especially when there is a lateral pressure, the shear forces between abutment and the dental implant become larger, easily causing a broken implant screw. In addition, under the occlusive force, it is apt to rotate for the upper part of prosthesis together with the abutment after conducting dental implant surgery. Therefore, an appropriate design of the dental implant plays an essential role in a successful restoration.

Secondly, the design of the implant denture. A proper design of implant denture can reduce the occurrence of complications and prolong its longevity. If the resultant pressure is beyond the implant's endurance, there will be possibility for a broken dental implant and a peripheral bone absorption which will eventually cause looseness of the dental implant. Thus in the design of the implant denture, several factors should be taken into consideration, including the number, the spacing, the position of the dental implant and the healthy condition of jaw teeth. Much attention should be paid to the pressure that the dental implant has to bear, and try to allocate that pressure evenly. An auxiliary retainer attached to the adjacent natural teeth can be a choice if necessary. What's more, the implant denture should enjoy a harmonizing occlusal relationship, with an extensive and stable contact for the centric jaw, but little contact for the non-centric jaw in order to reducing the lateral force applied on the dental implant. Try to choose proper materials that suit the specific condition of the dental implant. Sometimes composite resin is helpful to reduce the resultant force which the dental implant has to endure.

Finally, Peripheral Periodontitis is a kind of the most common seen complications. It's necessary to take measures to protect the dental implant, because the structure of its peripheral tissues are too weak to resist the invasion of bacteria and react to the inflammation promptly. How to reduce the accumulation of plaque on the prosthesis and dental implant surface is currently an important topic worldwide. The clinical application and research of implant osseointegration have greatly extended its range of study. Since the tactile and reactive function share a connection with the neuroreceptor of the periodontal ligament, the osseoperception will build a contact with the innervation inside and outside the bone, which lays an essential foundation for creating a proper periodontal environment around the dental implant.