Evulation of the effects of two different types of the pre-orthodontic trainer (POT) devices in class ii malocclusion by cephalometric recordings

Myofunctional habits such as abnormal tongue and lip movements cause craniofacial development and orthodontic anomalies. (6, 9, 10, 13, 15, 19, 20) The most important purpose of using myofunctional appliances is to maintain muscular balance, to eliminate oral dysfunction and to correct or reduce the protrusion/ proclination of maxillary incisors (15). Although the effects of growth and development of craniofacial structures on tooth positions of perioral muscles are widely discussed, there are many unanswered questions and various orthodontic treatment methods related to muscle movement (14). One of the many advantages of using POT device for correction of Class II malocclusion is expressed as the prevention of bruxism by the relaxation of muscles (10). It has also been suggested that the device treats the openbite anomaly by eliminating the negative effects of the tongue and the lower lip during swallowing (19). It has been reported that it contributes to normal development and stabilization by correcting abnormal tongue and lip function (8). The POT device can be used to interfere with anomalies during early mixed dentition. Thus, it is stated that complicated interventions such as permanent tooth extraction or orthognathic surgery can be prevented (1). Although many advantages of treatment with the POT device have been mentioned, very few scientific researches and compilations have been found (2,3). To date, the effect of treatment with POT device on Class II malocclusions has been researched by lateral cephalometric film, orthodontic casts and clinical analysis (2, 3, 4, 7, 10, 11, 16, 19) . In addition, studies on the effects of POT on the activity of masticatory muscles have been evaluated by electromyography (3, 12, 17, 18). Some researchers also evaluated the effects of the device with three-dimensional facial analysis and electromyography (5). The aim of this parallel-controlled study was to determine the efficacy of T4K and K2 in the treatment of Class II Division I from pre-orthodontic trainer (POT) devices by the evaluation of cephalometric X-ray analysis. Material and Method Our research consisted of 45 individuals who applied to Istanbul University Faculty of Dentistry Department of Orthodontics for treatment. 45 individuals were divided into 3 groups of 15 people. These groups; 1. T4K-treated patient group (T4K group), 2. Patient group treated with K2 (group K2), 3. Control group. The criteria of inclusion to our study in the Istanbul University Faculty of Dentistry Department of Orthodontics are the same for these three groups and these criteria are: • Class II division I malocclusion due to mandibular retrognathia, • Mixed dentition, • Upper lip deficiency, • Between 6 and 12 years of age, • Cases with minimal crowding, • Cases with no maxillary constriction, • Cases without cross-bite and asymmetry, • Non-syndromic cases, • Only female patients. In T4K group, K2 group and the control group from each patient, lateral cephalometric x-ray was taken from the beginning (T0) and at the end of treatment (T1). Each film was drawn by the same doctor with the help of NemoCeph 12.12 VERSION (SOFTWARE NEMOTEC, S.L., Madrid España) programme. The data obtained were compared with each other and between groups. In order to carry out our research, Ethics Committee Approval was obtained from Istanbul University Medical Faculty Clinical Research Ethics Committee No. 144 dated 17.01.2014. Statistical analysis were performed with the help of SPSS version 17.0 (IBM, Armonk, New York, United States, 2010). The normal distribution of the variables was analyzed by histogram graphs and Kolmogorov-Smirnov test. The mean, standard deviation, and median values were used when providing descriptive analyzes. Nonparametric variables were evaluated among the groups and Mann Whitney-U Test was used. The Wilcoxon test was used to analyze the change in the group. P-values below 0.05 were evaluated as statistically significant results. PARAMETRELER Kontrol K2 T4K K2-Control Group T4K- Control Group K2-T4K Group Ort s.s. Medyan Ort s.s. Medyan Ort s.s. Medyan P1 P2 P3 SNA 0,33 ±0,82 0,00 1,07 ±0,80 1,00 0,27 ±1,10 0,00 0,682 0,982 0,695 SNB 0,27 ±0,80 0,00 1,47 ±1,06 1,00 1,27 ±1,28 1,00 0,439 0,190 0,078 ANB -0,20 ±0,68 0,00 -1,20 ±0,77 -1,00 -0,93 ±1,33 -1,00 1,000 0,078 0,078 Witts -0,19 ±0,49 0,00 -1,25 ±1,26 -1,10 -1,24 ±1,33 -1,20 0,851 0,252 0,146 SN/GoMe -0,27 ±1,03 0,00 -1,40 ±1,64 -1,00 -1,00 ±0,93 -1,00 0,173 0,149 0,138 Y axis -0,07 ±0,59 0,00 -0,53 ±1,06 0,00 -0,13 ±1,36 0,00 0,818 0,912 0,864 ANSPNS/GoMe -0,20 ±0,86 0,00 -1,60 ±1,84 -2,00 -1,07 ±1,58 -1,00 0,716 0,153 0,311 Occlusion/SN 0,07 ±0,59 0,00 -1,13 ±1,77 -1,00 -0,40 ±1,30 0,00 0,683 0,424 0,780 Jarabak ratio 0,00 ±0,01 0,00 0,13 ±0,14 0,10 0,00 ±0,02 0,00 0,682 0,824 0,667 Saddle Angle ArSN -0,27 ±2,02 0,00 -2,60 ±4,58 -2,00 0,27 ±6,08 0,00 0,313 0,813 0,783 GnGoAr Angle 0,13 ±0,64 0,00 2,27 ±2,89 2,00 0,60 ±1,68 0,00 0,902 0,626 0,613 SN/ANS-PNS -0,33 ±0,62 0,00 -1,13 ±1,51 -1,00 -0,47 ±2,20 0,00 0,651 0,604 0,932 N-Me 0,23 ±0,57 0,00 2,73 ±1,87 2,70 1,40 ±0,61 1,60 0,005** <0,001*** 0,723 S-Go 0,29 ±0,67 0,00 2,65 ±2,16 2,30 2,20 ±2,11 2,00 0,441 0,162 0,416 Go-Me 0,21 ±0,61 0,00 1,98 ±1,31 1,40 1,01 ±1,52 1,10 0,233 0,320 0,739 İnterincisal Angle -0,13 ±1,55 0,00 -1,07 ±3,90 0,00 -0,60 ±5,12 0,00 0,941 0,756 0,966 U1/SN 0,07 ±2,34 0,00 -2,20 ±3,99 -1,00 -2,07 ±4,70 -2,00 0,699 0,223 0,587 ANS-PNS/U1 0,73 ±2,34 0,00 -2,33 ±4,89 -1,00 -2,13 ±5,64 -2,00 0,242 0,179 0,692 U1/NA angle 0,73 ±2,34 0,00 -3,07 ±4,10 -2,00 -2,73 ±7,16 -1,00 0,071 0,005** 0,336 U1/NA mm 0,19 ±0,50 0,00 -0,77 ±1,30 -1,00 -0,51 ±1,41 -1,00 0,171 0,005** 0,103 L1/NB angle -0,27 ±0,70 0,00 2,73 ±4,62 1,00 2,07 ±2,79 2,00 0,017* 0,004** 0,884 L1/NB mm 0,00 ±0,00 0,00 0,92 ±0,99 0,80 0,82 ±0,91 0,80 <0,001*** <0,001*** 0,917 IMPA 2,20 ±4,48 1,00 4,20 ±0,41 4,00 3,27 ±4,68 3,00 0,006** 0,016* 0,425 Overjet -0,78 ±1,74 -0,10 -0,87 ±0,70 -1,00 -0,59 ±2,10 -0,70 0,018* 0,042* 0,162 Overbite 0,09 ±0,63 0,00 -0,65 ±0,87 -1,00 -0,41 ±1,20 -0,70 0,287 0,125 0,393 Ls 0,19 ±0,64 0,00 -0,73 ±1,38 -0,60 -0,53 ±0,96 -0,60 0,075 0,110 0,308 Li 0,17 ±0,53 0,00 0,90 ±1,18 0,50 0,28 ±1,04 0,10 0,014* 0,049* 0,157 ¹Mann Whitney-U Testi * =p<0,05 ** =p<0,01 *** =p<0,001 Discussion There was no statistically significant difference in SNA value of T4K group before and after treatment. The mean value of SNB treatment was 75,130 ± 3,180 at the beginning of the treatment and at the end of the treatment. The mean end of treatment was 76,400 ± 3,520. While the mean value of ANB was 6.80 ± 1.90; The mean end of treatment was 5,870 ± 2,390. Witts mean value of treatment was 4,430 ± 1,770, and the mean end of treatment was 3.190 ± 2.10. While there was no statistically significant difference in the SNA value in the K2 group, the mean value of SNB at the beginnig of the treatment was 77,070 ± 4,230 and the end of treatment was 78,530 ± 4,260. While the mean value of ANB at the beginning of the treatment was 6,600 ± 1,880, and at the end of treatment was 5,400 ± 2,200. The mean value of Witts at the beginning of the treatment was 4,470 ± 2,350 and at the end of the treatment was 3,220 ± 2,360. Similar to the studies in the literature in the POT groups, a statistically significant increase in the SNB at the beginning of the treatment and at the end of the treatment. When the differences between the beginning of the treatment and end of the treatment values of the T4K group were examined, the mean value of L1-NB angle at the beginning of the treatment was 29,070 ± 5,350, and at the end of treatment was 31,130 ± 4,840. The mean value of L1-NB mm at the beginning of the treatment was 5.6 ± 1.83 mm and at the end of the treatment was 6.42 ± 1.81 mm. The mean value of overjet at the beginning of the treatment was 6.12 ± 1.02 mm and at the end of the treatment was 5.53 ± 2.3 mm. A statistically significant difference was determined only in these three dental measurements. These values show us that the reduction of the overjet amount is tooth-borne. The mean value of U1 / SN at the beginning of the treatment was 1050 ± 7,290, and at the end of the treatment was 102,80 ± 6,210. The mean value of L1-NB angle at the beginning of the treatment was 29,930 ± 9,410 and at the end of the treatment was 32,670 ± 7,490. While the mean value of L1-NB mm at the beginning of the treatment was 5,65 ± 3,1 mm, at the end of the treatment was 6,57 ± 2,63 mm. The mean value of IMPA at the beginning of the treatment was 970 ± 4.520, and at the end of the treatment was 101,20 ± 4,410. The mean value of overjet at the beginning of the treatment was 7.33 ± 2.02 mm and at the end of the treatment was 6.46 ± 1.99 mm. The changes in these values were found to be statistically significant. The amount of overjet in treatment with K2 device did not decrease only with the proclination of lower incisors. In addition, it was determined that the retroclination of the upper incisors induced the decrease in the amount of overjet. In contrast to the T4K group, we think that the significant difference of IMPA and U1 / SN from the K2 group depends on the structural characteristic of K2 (Fränkel's cage system featured dynamicore structure). In the T4K group, the mean value of Ls at the beginning of the treatment was 2.43 ± 1.56 mm and at the end of the treatment was 1.91 ± 1.62 mm. While the mean value of Li at the beginning of the treatment was 2.15 ± 2.45 mm, the mean value after treatment was 2.43 ± 2.74 mm. A statistically significant difference was found in both lips. In the K2 group, the mean value of Li at the beginning of the treatment was 2.25 ± 2.77 mm and at the end of the treatment was found to be 3.15 ± 2.6 mm. Only statistically significant difference was found in this parameter. This can be interpreted as the reflection of the lower incisor proclination to the soft tissue. No statistically significant difference was found between the control group soft tissue parameters at the beginning of treatment and the end-of-treatment values. Results In our study, there are two treatment groups treated with T4K and K2 Pre-orthodontic Trainer devices. The changes in the control group, which were formed with similar characteristics in the period of growth development, were compared to each other and between the groups. Thus, it is aimed to determine the effects of T4K and K2 devices on hard tissue (tooth and skeleton) and soft tissue. According to our findings; 1. It was determined that the SNB value was increased but this increase was related to the rotation in the counterclockwise direction rather than the skeletal growth of the mandible. 2. The effects of K2 and T4K devices on soft tissue and hard tissue are almost the same. The effects were observed more as dentoalveolar. We attributed skeletal effects to early treatment of patients. 3. The increase in the inclination of the upper incisor, which we only connected to the structural properties of the K2 device, was statistically significant. 4. Overjet decreased in treatment groups. 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