BACKGROUND:Molars are characterized by multi-root, multi-root canal, multi-directional, different geometric shape and distribution. Single-root canal teeth post-core theory was used to guide molar repair in the clinic. It is easy to cause root canal perforation or vertical fracture due to excessive post preparation. Therefore, it is necessary to make further study and investigation in the design of fiber post-resin core for repairing molars. OBJECTIVE: To evaluate the clinical therapeutic effects of fiber post-resin core with different numbers of posts in the repair of molar residual roots and crowns. METHODS: A total of 54 human molar residual roots and crowns with sound root canal filing in 48 patients were selected and restored with fiber post of different numbers and resin core as wel as complete coronal restoration. There were 17 cases (20 samples) restored with single fiber post core, 16 cases (18 samples) restored with double fiber post cores, and 15 cases (16 samples) restored with three fiber post cores. They were folowed up for 24 months and the repair results were compared. RESULTS AND CONCLUSION:After 24 months of folow-up, the success rates were 85%, 94% and 94% in the single fiber post, double fiber post and three fiber post groups, respectively, and no significant difference was detected among the three groups. Five failures were observed among 54 teeth: three cases of fiber post shedding in the single fiber post group, one case of fiber post shedding in the double fiber post group, and one case of fiberpost shedding in the three fiber post group, and no root fracture occurred. Three kinds of fiber post-resin cores for repairing molar residual roots and crowns can get a better short-term clinical result. The repair effects were not different because of the different numbers of fiber posts.

Fracture of multiple implants is rare.This report describes 1 case with the fracture of multiple implants related to occlusal over-load,bruxism,periodontitis and other factors in the posterior position.The fractured implants were removed and immediate reimplantation was performed.The panoramic film showed that the implants were integrated successfully 12 months after prosthesis.