[Clinical analysis of the short-term and long-term results of the implant-supported Trefoil dental rehabilitation in Russia].

THE AIM OF THE STUDY Was to presents the first clinical medium-term (18 months) results of implant-supported rehabilitation using this method in Russia, with the special attention paid to the assessment of the patient's quality of life on the GOHAI scale. MATERIALS AND METHODS The authors performed a clinical and paraclinical examination of 29 patients (20 women and 9 men). The age of the patients ranged from 47 to 88 (average value - 65.45±9.7). We performed a retrospective analysis of all patients operated from June 2017 till March 2019. The patients filled in GOHAI questionnaires about their state of health and quality of life (before treatment and 6 weeks post-surgery). Patients with one or more anterior teeth present as well as fully edentulous mandibles were included in the study. The antagonist teeth could be presented as complete dentures, natural teeth, or implant-supported fixed restorations. All patients received three Trefoil implants (Nobel Biocare AB) inserted with a torque of at least 35 Ncm. The Trefoil bar (Nobel Biocare AB) was used as the framework of the Trefoil bioengineering structure. Statistical processing of the results was performed using the SPSS 23 software. The t-test for dependent samples was used to compare the results of GOHAI surveys before and after the operation and the following statistical hypotheses were suggested: H0 - the results of the GOHAI survey before the operation do not differ from the results of the GOHAI survey after the operation; H1 - GOHAI pre-op survey results are different from GOHAI post-op survey results. A comparison was made between the GOHAI results before and after surgery in male and female patients using the t-test for independent samples. RESULTS 29 patients included in this (20 females and 9 males) with the mean age of 65 (range:47-88). The average time of operation (surgical operation, prosthetic stage including dental lab work) the Trefoil technique was 6.18 ± 0.87 hours. With the presence of teeth in the mandible, the operation took longer by an average of 45 minutes. Patients were followed for 15±6 months. No chipping of artificial teeth or fractures of the veneering was observed. The survival rate of restorations was 100%. The implant survival rate was 98.85%. The results of the GOHAI survey after surgery show a significant difference from the results of the pre-op survey. If we analyze the average values for the sample, it can be argued that the average result for the GOHAI survey before the operation (29.86) is significantly lower than the average one for the GOHAI survey after the operation (54.93). CONCLUSION Preliminary medium-term results of the Trefoil concept for implant-supported rehabilitation of the mandible indicate high patient satisfaction results after 6-18 months of follow-up. It requires a further comprehensive study to obtain data with more patients and over a longer follow-up period.