COMPARATIVE CHARACTERISTICS OF TRANSFERS SPLINTING TECHNIQUES IN THE PROCESS OF TAKING ONE-STAGE DOUBLE-LAYERED DENTAL IMPRESSIONS BY MEANS OF OPEN TRAY IMPRESSION TECHNIQUE

According to conclusions of ITI World Congress (2018), the accuracy of the dental impression determines the quality of the working model and, consequently, the fixation of the prosthetic restorations at the final stage. Inaccurate dental impression will inevitably lead to technical and biological complications (Wolfart S., 2016). According to Lee and co-authors (2019), the accuracy of the dental impression is influenced by the chosen method, namely closed or open tray, the presence or absence of transfers splinting and the choice of impression material type. The most accurate impression has been proved to be an impression taken with the use of an open tray impres-sion technique, by means of polyether impression material with preliminary transfers splinting using internally inter-faced implant system. The objective of the research was to evaluate the quality of implants placement transferring to the model by comparative analysis of different methods of clinical transfers splinting in order to take impressions using an open tray impression technique. Twelve clinical situations were studied. Four groups were formed according to the method of transfer splinting. Each group included 3 clinical cases. Impressions were taken with the use of an open tray impression technique in all clinical cases with preliminary custom-made trays with holes in the implants projections. A grading scale was created when assessing the quality of transfer splinting as a key factor in the accuracy of implant placement transferring. Each of the groups received from 1 to 4 points where 1 point was the worst result according to this criterion and 4 points meant the best one. Among the criteria for splinting quality evaluation, 1-3 criteria were considered to be subjective, criterion 4 was considered to be objective. Therefore, criterion 4 received coefficient ×2 in order to increase the objectivity of the results evaluation. There were 4 criteria: 1) The simplicity of the technique and the time spent splinting. 2) The cost of the technique. 3) Passivity when fixing the bridge prosthetic restoration after manufacturing. 4) Radiologically measured distance between the centers of implant analogues on the model relative to each other after an impression taking by means of different splinting techniques and deviation of the value from the position of the centers of implants heads tops after osseointegration according to CT scan. Analyzing the results of the research, splinting techniques were ranked according to the obtained points. Research group 1 scored 6 points using dental floss and flowable compomer. A considerable amount of time was spent splinting with relatively inexpensive technology. The passivity of the fixation was the worst in comparison with other methods and the largest error was determined radiographically. Group 4 scoring 17 points was determined as the best of the chosen techniques. Despite the high cost of the chosen technique, prosthetic restorations made after transfers splinting by means of this technique had the highest fixation accuracy and the lowest deviation of the implants analogues on the model radiographically in comparison with the position of the implants in the upper alveolar ridge and lower alveolar ridge due to the cost of the material based on poly-vinyl siloxane.