Comparison of three midsagittal planes for three-dimensional cone beam computed tomography head reorientation.

OBJECTIVE: This study compared three prominent midsagittal planes (MSPs) to identify the MSP that best approximates the true symmetrical MSP. METHODS: Forty-three patients (mean age, 23.0 ± 8.20 years) were grouped as follows: group 1 consisted of 10 patients with skeletal Class I and a menton (Me) deviation of < 2 mm; group 2, 11 patients with skeletal Class III and a Me deviation < 2 mm; group 3, nine patients with skeletal Class III and a Me deviation of 2 to less than 4 mm; and group 4, 13 patients with skeletal Class III and an Me deviation ≥ 4 mm. The candidate MSPs were established by three-dimensional (3D) cone beam computed tomography (CBCT) reorientation methods (RMs): (1) the MSP perpendicular to the Frankfort horizontal (FH) plane while passing through the crista galli and basion; (2) the MSP including the nasion, incisive foramen, and basion; (3) the MSP including the nasion, anterior nasal spine, and posterior nasal spine. The mean absolute distances (MADs) to the MSPs were calculated from the coordinates of 1,548 points on 129 CBCT images. The differences in the values of the 3D coordinates among RMs were compared. RESULTS: The MADs of the three RMs showed significant differences (p < 0.05). Most of the differences in values of the coordinates were not significant among RMs. CONCLUSIONS: Although the differences in distance among the three MSPs were minor, the MSP perpendicular to the FH plane while passing through the crista galli and basion best approximated the true symmetrical MSP.

Effects of various toothpastes on remineralization of white spot lesions.

OBJECTIVE: The purpose of this in vitro study was to examine the effects of fluoridated, casein phosphopeptide.amorphous calcium phosphate complex (CPP-ACP)-containing, and functionalized ß-tricalcium phosphate (fTCP)-containing toothpastes on remineralization of white spot lesions (WSLs) by using Quantitative light-induced fluorescence (QLF-D) Biluminator™ 2. METHODS: Forty-eight premolars, extracted for orthodontic reasons from 12 patients, with artificially induced WSLs were randomly and equally assigned to four treatment groups: fluoride (1,000 ppm), CPP-ACP, fTCP (with sodium fluoride), and control (deionized water) groups. Specimens were treated twice daily for 2 weeks and stored in saliva solution (1:1 mixture of artificial and human stimulated saliva) otherwise. QLF-D Biluminator™ 2 was used to measure changes in fluorescence, indicating alterations in the mineral contents of the WSLs, immediately before and after the 2 weeks of treatment. RESULTS: Fluorescence greatly increased in the fTCP and CPP-ACP groups compared with the fluoride and control groups, which did not show significant differences. CONCLUSIONS: fTCP- and CPP-ACP-containing toothpastes seem to be more effective in reducing WSLs than 1,000-ppm fluoride-containing toothpastes.

Evaluation of the relationship between upper incisor exposure and cephalometric variables in Korean young adults.

OBJECTIVE: The purpose of this study was to classify Korean young adults into 3 groups on the basis of upper incisor exposure rates (UIERs) and to compare the skeletal, dental, and soft tissue variables. METHODS: Samples were obtained from 127 students at the College of Dentistry, Wonkwang University in South Korea. Facial photographs of frontal posed smiles and lateral cephalograms of the subjects were taken. The subjects were divided into 3 groups on the basis of UIERs and 20 measurements were compared among the 3 groups. The correlations between the variables were determined. RESULTS: Male and female subjects showed significant differences in the group distribution. Male subjects showed higher frequencies of low smiles, and female subjects showed higher frequencies of high smiles. The vertical height of the anterior alveolar process of the maxilla directly correlated with the UIER. However, the UIER showed no significant correlation with the vertical height of the anterior basal bone or the inclination of the upper incisor axis. In female subjects, the upper central incisor clinical crown length showed an inverse correlation with the UIER. However, this variable showed no significant correlation with the UIER in male subjects. CONCLUSIONS: The UIER was directly correlated with the levator muscle activity of the upper lip and inversely correlated with the upper lip thickness, yet there was no correlation between the UIER and upper lip length at rest.

Placement angle effects on the success rate of orthodontic microimplants and other factors with cone-beam computed tomography.

INTRODUCTION: The purpose of this study was to evaluate the effect of placement angles on the success rate of orthodontic microimplants and other factors with cone-beam computed tomography images. METHODS: We examined 228 orthodontic microimplants implanted into the maxillary buccal alveolar bone of 130 patients (33 men, 97 women) with malocclusion. Vertical placement angle, horizontal placement angle, root proximity, and cortical bone thickness were measured, and the correlations between these measurements and orthodontic microimplant success rates and the correlations among the measurements were evaluated. RESULTS: The overall success rate was 87.7% (200 of 228). The orthodontic microimplant success rate statistically significantly increased as root proximity (distance from the orthodontic microimplant to the root surface) increased (P <0.05), but there were no statistical significances between placement angles and success rates, and cortical bone thickness and success rate (P >0.05). Correlations between placement angles and root proximity showed no statistical significance (P >0.05), but correlations between vertical placement angle and cortical bone thickness (P <0.001) and between horizontal placement angle and cortical bone thickness (P <0.01) showed statistical significance. A statistically significant (negative) correlation was found between vertical and horizontal placement angles (P <0.001). CONCLUSIONS: The success rate of orthodontic microimplants is not affected by placement angles and is more significantly affected by root proximity than by cortical bone thickness. Cortical bone thickness is affected by placement angles, but root proximity is not affected by placement angles.

Root proximity and cortical bone thickness effects on the success rate of orthodontic micro-implants using cone beam computed tomography.

OBJECTIVE: To evaluate factors (root proximity and cortical bone thickness) affecting the success rate of orthodontic micro-implants (OMIs) using cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: We examined 172 OMIs (1.2-1.3 mm in diameter, 8 mm in length) implanted into the maxillary buccal alveolar bone of 94 patients (33 men, 61 women) with malocclusion. Root proximity and cortical bone thickness were measured, and the correlations between these measurements and OMI success rates were evaluated. RESULTS: The overall success rate was 90.7% (156/172). The success rate increased as the distance between the root surface and OMI increased, showing a highly significant statistical correlation (P < .05). As the cortical bone thickness increased, the success rate increased, showing a slight, nonsignificant correlation (P > .05). Thus, the success rate of OMIs was affected more significantly by root proximity than cortical bone thickness. CONCLUSIONS: When inserting OMIs, increasing the distance from the OMI to the root surface will significantly improve success rates.