Background: The aim of this study was to evaluate the factors that may affect implant fixture fractures. Methods: Patients who experienced implant fixture removal at Seoul National University Bundang Hospital from 2007 to 2015 due to implant fixture fracture were included. Implant/crown ratio, time of implant fracture, clinical symptoms before implant fracture, treatment of fractured implants, and the success and survival rate of the replaced implants were evaluated retrospectively. Results: Thirteen implants were fractured in 12 patients. Patient mean age at the time of fracture was 59.3 years. Of the 13 implants, 7 implants were placed at our hospital, and 6 were placed at a local clinic. The mean crown/ implant ratio was 0.83:1. The clinical symptoms before fracture were screw loosening in five implants, marginal bone loss in five implants, and the presence of peri-implant diseases in five implants. All the fractured implants were removed, and 12 out of the 13 sites were re-implanted. Parafunctions were observed in two patients: one with bruxism and one with attrition due to a strong chewing habit. Conclusions: Several clinical symptoms before the fracture of an implant can predict implant fixture failure. Therefore, if these clinical symptoms are observed, appropriate treatments can be taken before more serious complications result.

The authors analyzed the three-dimensional postoperative condylar position change across the plating systems. This retrospective study was conducted with the patients who underwent bilateral sagittal split ramus osteotomy with setback surgery. The condylar change was analyzed from preoperative cone-beam computed tomography to postoperative 1 month (T1) and postoperative 6 months (T2) using superimposition software, automatically merging based on the anterior cranial base. The condylar changes during T1 and T2 were analyzed across the four types of plates (4-hole sliding, heart-shaped, 3-hole sliding, and 4-hole conventional) Mean intraclass correlation coefficient values were consistently high for each measurement (>0.850). During T1, the conventional plate had a decreased condylar anterior distance when compared with the 3-hole sliding plate ( P = 0.032). During T2, the conventional plate had an increased condylar posterior distance when compared with the 3-hole sliding plate ( P = 0.031). S uperimposition software based on the anterior cranial base could be available for measurement of condylar position with highly reproducible results. After bilateral sagittal split ramus osteotomy, the 3-hole sliding plate could effectively compensate for the anterior displacement of the condyle compared to other plates.

The aim of this study was to compare and analyze the survival rate, success rate, and loss of marginal bone of internal and external hexes and presence or absence of microthreads of implant immediately installed after tooth extraction. Forty-four implants were installed in 30 patients, average follow-up period was 80 months, and each product was divided into 3 groups. Group 1 is Osstem TS III implant, Group 2 is Osstem US II implant, and Group 3 is Implantium implant. Panoramic and periapical radiographs were used to measure the marginal bone loss. One implant was removed during the study period, and TS III had a survival rate of 100% and a success rate of 88%, US II had a survival rate of 100% and a success rate of 100%, Implantium had a survival rate of 95% and a success rate of 89%. These results suggest that Osstem and Dentium products show good clinical prognosis when implant is immediately installed after extraction, so it may be a good treatment option in the case of indications.

Background : Mechanical complications are inevitable problems in implant restoration. Fracture of an implant fixture is quite rare, but it is one of the complications that surgeons and patients encounter, and requires implant removal (explantation) and re-implantation.Aim/Hypothesis : The aim of this study was to evaluate the factors that may affect the fracture of implant fixtures.Material and Methods : Patients who experienced implant fixture removal at Seoul National University Bundang Hospital from 2007 to 2015 due to implant fixture fracture were selected. Implant Crown ratio, time of implant fracture, clinical symptoms before implant fracture, treatment of fractured implants, success and survival rate, and marginal bone loss of the replaced implants were evaluated retrospectively. Marginal bone loss was measured using panoramic or periapical radiographs. After calculating the enlargement ratio of each radiograph, the amount of marginal bone loss was measured at the mesial and distal sides, and the average was obtained.Results : Thirteen implants were fractured in 12 patients. The mean age of the patients at the time of the fracture was 59.3 years. Of the 13 implants, seven implants were installed in our hospital, and six were implanted in a local clinic. The mean crown implant ratio was 0.83-1. The clinical symptoms before fracture were screw loosening in five implants, marginal bone loss in five, and peri-implant diseases were observed in five. All fractured implants were removed and 12 out of 13 implants were re-implanted. Parafunctions were observed in two patients-one with bruxism and one with attrition due to a strong chewing habit. Six of the upper prostheses were single crown prostheses, and seven were two or more fixed prostheses. There are no cantilevers. The seven implants installed in our hospital took an average of 61.7 months to fracture after prosthesis completion. The average marginal bone loss of the 12 implants re-installed was 0.13 mm, and the success and survival rates were all 100%. Conclusion and Clinical Implications: Screw loosening, peri-implantitis and marginal bone loss were observed before fracture of the implant fixture. Therefore, when symptoms are observed, care should be taken to prevent fracture of the implant.

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