New virtual orthodontic treatment system for indirect bonding using the stereolithographic technique / 대한치과교정학회지

The purpose of this article is to introduce a new virtual orthodontic treatment (VOT) system, which can be used to construct three-dimensional (3D) virtual models, establish a 3D virtual setup, enable the placement of the virtual brackets at the predetermined position, and fabricate the transfer jig with a customized bracket base for indirect bonding (IDB) using the stereolithographic technique. A 26-year-old woman presented with anterior openbite, crowding in the upper and lower arches, and narrow and tapered upper arch, despite having an acceptable profile and balanced facial proportion. The treatment plan was rapid palatal expansion (RPE) without extraction. After 10 days of RPE, sufficient space was obtained for decrowding. After a 10-week retention period, accurate pretreatment plaster models were obtained using silicone rubber impression. IDB was performed according to the protocol of the VOT system. Crowding of the upper and lower arches was effectively resolved, and anterior openbite was corrected to normal overbite. Superimposition of the 3D virtual setup models (3D-VSM) and post-treatment 3D virtual models showed that the latter deviated only slightly from the former. Thus, the use of the VOT system helped obtain an acceptable outcome in this case of mild crowding treated without extraction. More cases should be treated using this system, and the pre- and post-treatment virtual models should be compared to obtain feedback regarding the procedure; this will support doctors and dental laboratory technicians during the learning curve.

A speech-phonetic study on the pronunciation of the openbite patients / 대한치과교정학회지

This study aimed at examining speech defects of open bite patients, which were analized in terms of formant frequency for vowels and word pronunciation length for consonants. In addition, the upper and lower lip (perioral m.) activity was tested by the EMG. The tongue force was measured by the strain gauge, and the speech discrimination test was carried out. One experimental group and one control group were used for this study and they were respectively composed of six female openbite patients and six normal-occlusion females. Eight monophthongs, two fricatives and two affricatives were chosen for speech analysis. Speeches of the above-mentioned groups were recorded and then analized by the ILS/PC-I software. Four hundred most frequently used monosyllables were also chosen for discrimination score. Openbite patients showed the following characteristics: 1. Abnormality in case of /a/, /epsilon/, /e/, /i/ F2 and /e/, /a/ F1. 2. Significantly elongated length in their pronunciation of /h/ and /Ch/ and somewhat elongated length also in their pronunciation of /s/ and /c/. 3. Significant upper lip activity according to the EMG test during pronunciation of the bilabial consonants. 4. Relatively weak tongue force according to the strain gauge measurement. 5. According to the speech discrimination test, high rate of misarticulation in case of (a) initial /p/ /s'/ and /ts'/, (b) /a/, /epsilon/, /e/, /je/, /o/, /phi/, /jo/, /u/, /we/, and /i/ (c) final /eta/.

A sound spectrographical study on the Korean vowels and consonants pronounced by openbite patients: frequency analysis / 대한치과교정학회지

The study was undertaken to ascertain the speech defect of patients with malocclusion, especrally of poenbite patients, by means of the spectral analysis method. The expermental group was composed of ten female openbite patients and their mean age was 13.8 yrs. The control group was also composed of ten female girls ans then mean was 13.7 yrs. As for the speech materisl, eight Korean monphthrongs ans two Korean fricatives and two affricatives were used Speeches were recorded and then analyzed by a Kay 7800 drgital sonagraph. Formant frequency level or range was used as a phonemic parameter. The results were as follows. 1. Among Vowels /a/ F1,F3, and F1/F2 showed abnormahty /o/and/omega/F2,F2-F1 and F1/F2 showed abonrmahty. 2. Among Consonants /s/and/h/ The upper and lower borders of the frequency range showed abnormahty. /f/ The lower border of the ferquency range showed abonormahty. /C(h)/ The upper and lower borders of the frequency range and concentration point showed abonormahty.