ASSESSMENT OF THE PARAMETERS OF THE INTEROCCLUSION RELATIONSHIP IN THE PROCESS OF MESIALIZATION OF THE LOWER MOLARS WITH THE USE OF T-SCAN
Authors: Melnyk V.S. , Rivis O.Yu. , Horzov L.F. , Rivis M.V. , Bun Yu.M. 
Published: June 2020

The aim of the study. Conduct a digital analysis of the distribution of relative force occlusal load in the area of the second permanent mandibular molars before and after their mesialization.
Research methods. In order to evaluate the distribution of inter-occlusal force load in the process of mesialization of molars on the mandible, two clinical study groups were formed. The first group consisted of 32 persons (18 women / 56.25% and 14 men / 43.75%) aged from 18 to 25 years, who had orthodontic treatment using braces and mini-implants. The second group included 30 people (19 women / 63.33% and 11 men / 36.67%), orthodontic treatment was performed using a brace system without additional intraosseous support on the mini-implants.
T-scan apparatus investigated the distribution of relative force occlusal load in the area of the second permanent mandibular molars before and after orthodontic intervention.
Results of the study. The use of the T-scan apparatus is an accurate and informative tool for analyzing the distribution of functional occlusal force load within the dentition. During the analysis of the parameters of the chewing load in the area of the second permanent molars on the mandible before orthodontic treatment, an increase of this index was found in almost all patients of both study groups. In the first group in 4 (12.5%) persons the maximum relative occlusive force load in the area of the second permanent molars on the mandible was 10–20%, which is the range of the norm; in 15 (46.9%) cases this indicator was 20–30. %, in 10 (31.2%) patients had 30-40%, and in 3 (9.4%) exceeded 40%. In the second group, the parameters of the relative force occlusal load in the area of the second permanent molar on the mandible were as follows: in 5 (16.7%) persons in the range of 10-20%, in 13 (43.3%) persons - 20-30%, in 10 (33.3%) patients - 30-40% and in 2 (6.7%) patients more than 40%.
After treatment, normalization of the relative occlusal force load was observed in the area of the second permanent molars on the lower jaw in the majority of patients of both study groups. In particular, in the first group in 21 (65.6%) persons the parameters of occlusal load were in the range of 10–20%, in 11 (34.4%) persons were 20–30%. In the second study group, 17 (56.7) patients observed parameters of the occlusal load on the second molar in the range of 10-20%, in 12 (40%) persons - 20-30% and in one (3.3%) patient 30-40%.
In addition, moving molars involves changing the usual occlusal ratios associated with the non-identity factor in the shape and size of the first and second molars.
At the same time, occlusal contacts on all other teeth are altered due to their alignment with the orthodontic equipment and the appearance of new contact points that did not interact before the start of treatment.
Conclusions. The analysis of the distribution of the relative occlusal load in the area of the second permanent molars on the lower jaw with the help of T-scan after orthodontic treatment revealed the normalization of this indicator in the majority of patients in both study groups. Specifically, in the first group, 21 (65.6%) subjects had parameters of relative occlusal load within the range of 10–20%, and in 11 (34.4%) individuals were 20–30%. In the second study group, 17 (56.7%) patients were in the range of 10–20%, 12 (40%) patients - 20–30% and one (3.3%) patients 30–40%. The data obtained in both the first and second study groups indicate the need to perform procedures of grinding after orthodontic intervention to achieve appropriate occlusive normalization, the volume of which in each clinical situation is determined individually under the control of the T-scan apparatus.