ABSTRACT
OBJECTIVE: The aim of this study was to evaluate the reliability of measurements obtained after the superimposition of three-dimensional (3D) digital models by comparing them with those obtained from lateral cephalometric radiographs and photocopies of plaster models for the evaluation of upper molar distalization. METHODS: Data were collected from plaster models and lateral cephalometric radiographs of 20 Class II patients whose maxillary first molars were distalized with an intraoral distalizer. The posterior movements of the maxillary first molars were evaluated using lateral cephalometric radiographs (group CP), photocopies of plaster models (group PH), and digitized 3D models (group TD). Additionally, distalization and expansion of the other teeth and the degrees of molar rotation were measured in group PH and group TD and compared between the two groups. RESULTS: No significant difference was observed regarding the amount of molar distalization among the three groups. A comparison of the aforementioned parameters between group PH and group TD did not reveal any significant difference. CONCLUSIONS: 3D digital models are reliable to assess the results of upper molar distalization and can be considered a valid alternative to conventional measurement methods.
Subject(s)
Humans , Hydrogen-Ion Concentration , Molar , ToothABSTRACT
OBJECTIVE: The aim of this study was to evaluate the reliability of measurements obtained after the superimposition of three-dimensional (3D) digital models by comparing them with those obtained from lateral cephalometric radiographs and photocopies of plaster models for the evaluation of upper molar distalization. METHODS: Data were collected from plaster models and lateral cephalometric radiographs of 20 Class II patients whose maxillary first molars were distalized with an intraoral distalizer. The posterior movements of the maxillary first molars were evaluated using lateral cephalometric radiographs (group CP), photocopies of plaster models (group PH), and digitized 3D models (group TD). Additionally, distalization and expansion of the other teeth and the degrees of molar rotation were measured in group PH and group TD and compared between the two groups. RESULTS: No significant difference was observed regarding the amount of molar distalization among the three groups. A comparison of the aforementioned parameters between group PH and group TD did not reveal any significant difference. CONCLUSIONS: 3D digital models are reliable to assess the results of upper molar distalization and can be considered a valid alternative to conventional measurement methods.
Subject(s)
Humans , Hydrogen-Ion Concentration , Molar , ToothABSTRACT
OBJECTIVE: This study evaluated the cytotoxicity and genotoxicity of fixed orthodontic treatment with three different light-cured orthodontic bonding composites by analyzing micronucleus (MN) formation in the buccal mucosa during a 6-month period. METHODS: Thirty healthy volunteers were selected from consecutive patients referred for orthodontic treatment. Equilibrium 2 brackets and molar tubes (Dentaurum) were bonded with three different light-cured orthodontic bonding composites-Transbond XT (3M Unitek), Kurasper F (Kuraray Europe), or GrenGloo (Ormco Corporation)- to all teeth in both arches. Exfoliated buccal epithelial cells were scraped from the middle part of the inner cheeks with sterile cement spatulas before treatment and at 1, 3, and 6 months after treatment. MNs and nuclear alterations, such as karyorrhexis (KR), karyolysis (KL), and binucleated cells (BNs), were scored under a light microscope. Repeated measure ANOVA was used to calculate statistical differences in degenerative nuclear abnormalities. RESULTS: MN rates did not significantly differ among different time points within the same cell type (p > 0.05). In contrast, the number of BNs in buccal epithelial cells significantly increased in all composite groups (p < 0.01, Transbond XT; p < 0.001, Kurasper F and GrenGloo). KL frequency significantly increased between the beginning and end of the study in the Kurasfer F (0.80 +/- 0.79 to 1.90 +/- 1.10; p < 0.05) and GrenGloo (1.30 +/- 1.06 to 2.40 +/- 1.08; p < 0.05) groups. CONCLUSIONS: After 6 months of fixed orthodontic treatment with different light-cured composites, morphological signs of cytotoxicity were observed but genotoxic effects were absent.
Subject(s)
Humans , Cheek , Epithelial Cells , Healthy Volunteers , Micronucleus Tests , Molar , Mouth Mucosa , ToothABSTRACT
OBJECTIVE: The purpose of this study was to compare the shear bond strength (SBS) of brackets and microleakage of a tooth-adhesive-bracket complex bonded with a direct and an indirect bonding technique after thermocycling. METHODS: Fifty non-carious human premolars were divided into two equal groups. In the direct bonding group a light-cured adhesive and a primer (Transbond XT) was used. In the indirect-bonding group, a light-cured adhesive (Transbond XT) and chemical-cured primer (Sondhi Rapid Set) were used. After polymerization, the teeth were kept in distilled water for 24 hours and thereafter subjected to thermal cycling (500 cycles). For the microleakage evaluation, 10 teeth from each group were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, and examined under a stereomicroscope. Fifteen teeth from each group were used for SBS testing with the universal testing machine and adhesive remnant index (ARI) evaluation. Data were analyzed using the Mann-Whitney U test, Chi-square test, and Fisher's exact test. RESULTS: There were no statistical differences on SBS and microleakage between the two bonding techniques. The indirect bonding group had a significantly lower ARI score. Bracket failures were obtained between enamel-resin interfaces. CONCLUSIONS: The type of bonding technique did not significantly affect the amount of microleakage and SBS.