The relationship of the teeth to the gap and the interposition of the abutment teeth should be carefully checked before preparation of the abutment teeth. Determine the seating tract. Take a study model if necessary. The abutment teeth of a precision attachment denture need to be protected by a full crown or 3/4 crown, and the preparation principles are the same as those for fixed denture abutment teeth, and the retention force should be increased as much as possible, but the preparation of abutment teeth for attachments also has its special requirements. The abutment preparation for intracoronal precision attachments must be located in the intrinsic anatomical form of the abutment crown, so the grinding of the tooth body is more and deeper. Second, the abutment preparation of extra-coronal precision attachment 1, the gingival height of the abutment teeth, the gingival height of the attachment by clasp at least 6 mm . 2. The gingival height of the double crown attachment should be at least 5 mm. 3, The gingival height of the peg channel is at least 5mm. 4.The gingival height of magnetic retainer should not be less than 4mm. Third, the impression method In the general absence, the production of precision attachment denture, as long as the accurate anatomical position of the relationship between the tooth and the mucosa can be obtained in the impression, but for the free end of the absence, in order to improve the stability of the denture base, reduce the load on the abutment teeth, uniform distribution of stress, should take the impression of the alveolar ridge functional pressure state. IV. Trial wear and bonding of the denture The fabrication of a precision attachment denture does not require special techniques, however, because of the high requirements for precision. Each step in the production process should be careful and accurate, and if this can be done, there is generally no problem in the fitting process, otherwise, the reason should be carefully found, and the attachment should not be easily changed. After the denture is in place, the patient should be allowed to try it on for a few days before bonding. In the process of bonding, the denture should always be kept in the support recess of the abutment. One of the advantages of a precision attachment denture is that it is easy to repair and replace. The attachment may wear out or break due to abnormal occlusal forces between the two parts due to long-term wear and functional activities. The following factors have a significant effect on the wear of the attachment and should be noted. 1. Slight inconsistency between the various seating channels of the abutment teeth. 2. A large difference in the elasticity of the metal material between the two parts of the attachment. 3. Small contact area between the metal materials of the two parts of the attachment. 4.The stability of the denture is poor. 5.After the attachment is damaged, the damaged part can be replaced by the corresponding product provided by the manufacturer.