Effects of different rapid maxillary expansion appliances on facial soft tissues using three-dimensional imaging.

OBJECTIVE: To determine three-dimensional (3D) effects of three different rapid maxillary expansion (RME) appliances on facial soft tissues. MATERIALS AND METHODS: Forty-two children (18 boys, 24 girls) who required RME treatment were included in this study. Patients were randomly divided into three equal groups: banded RME, acrylic splint RME, and modified acrylic splint RME. For each patient, 3D images were obtained before treatment (T1) and at the end of the 3-month retention (T2) with the 3dMD system. RESULTS: When three RME appliances were compared in terms of the effects on the facial soft tissues, there were no significant differences among them. The mouth and nasal width showed a significant increase in all groups. Although the effect of the acrylic splint RME appliances on total face height was less than that of the banded RME, there was no significant difference between the appliances. The effect of the modified acrylic splint appliance on the upper lip was significant according to the volumetric measurements (P < .01). CONCLUSIONS: There were no significant differences among three RME appliances on the facial soft tissues. The modified acrylic splint RME produced a more protrusive effect on the upper lip.

Effects of strontium ranelate on sutural bone formation: a histological and immunohistochemical study.

AIM: Rapid maxillary expansion is performed to correct a skeletal transverse deficiency of the maxilla, which is a frequently- encountered orthodontic anomaly. Strontium ranelate (SrR) is a novel agent that has a dual action, involving anti-resorptive and bone-forming effects. The aim of this study was to evaluate the effects of systemically applied SrR on osteoblastic bone formation after maxillary expansion on the mid-palatal suture of rats using histological and immunohistochemical tests. MATERIALS AND METHODS: A total of 24 Wistar rats were randomly divided into two equal groups. In all animals, five-day inter-premaxillary expansion was applied and maintained for a seven-day retention period, during which 625mg/kg/day SrR diluted with saline solution was administered orally to the experimental group. The rats were sacrificed and the tissues prepared for histological and immunohistochemical examinations after the retention period. RESULTS: Osteoblastic activity and the width of the blood vessels in the suture area were significantly increased in the SrR group compared with the control group (p < 0.051. Ossification was also observed to be active under light microscopy by staining with hematoxylin and eosin in the experimental group. Immunohistochemical labelling performed using osteonectin, osteocalcin, TGF-P and VEGF antibodies revealed significant immunoreactivity in the experimental group (p < 0.05). CONCLUSION: It may be concluded that SrR contributed to stimulatory osteogenesis in the expansion region. Therefore, a retention period may be shortened and relapse possibly reduced, following the application of SrR after the expansion.

Physical properties of different orthodontic cements.

INTRODUCTION: We evaluated the water absorption, solubility, and compressive strength of different cements and resin-modified glass ionomer cements (RMGICs), namely Adhesor®, Ketac(™) Cem, Ortho Band Paste LC(™), Glass Ionomer Band Cement, and Transbond(™) Plus. Our aims were to compare the mechanical and physical properties of the cements widely used in orthodontics and to define the most suitable cements in an oral environment in terms of those characteristics. MATERIALS AND METHODS: To assess compressive strength, the cements were subjected to compression tests done on a universal testing machine. To test water absorption and solubility, the weight changes in cement specimens were determined after immersion in distilled water for 1, 7, and 30 days. RESULTS: Adhesor® and Ketac(™) Cem presented significantly higher solubility values than other cements after water immersion for 1, 7, and 30 days (p < 0.001). CONCLUSION: Our results revealed that the traditional orthodontic cements have higher water solubility and water absorption values as well as lower compressive strength values than the RMGICs used in this study. Furthermore, Transbond(™) Plus revealed the highest compressive strength, whereas Adhesor® showed the lowest.

Effects of contemporary orthodontic composites on tooth color following short-term fixed orthodontic treatment: a controlled clinical study.

BACKGROUND/AIM: To determine the color alterations of natural teeth associated with different orthodontic composites used in comprehensive short-term treatment. MATERIALS AND METHODS: Twenty-two patients were treated with fixed appliances and 22 untreated subjects were also evaluated. Lower incisors were bonded with different orthodontic composites: 42 with Grengloo, 41 with Light Bond, 31 with Kurasper F, and 32 with Transbond XT. The color parameters of the Commission Internationale de l'Eclairage (CIE) were measured for each tooth with a spectrophotometer. Color assessment in relation to time, adhesive material, and their interaction was made with 2-way mixed analysis of variance (ANOVA) and 1-way ANOVA for the color differences (ΔE*). Further analyses were done using Tukey's honestly significant difference tests and paired-samples t-tests. RESULTS: The color of teeth was affected by treatment. The mean L* and a* values increased, whereas the mean b* values decreased. Total color differences of teeth demonstrated visible color changes clinically after treatment, ranging from 1.12 to 3.34 ΔE units. However, there were no significant differences for color of enamel. CONCLUSION: Teeth may be discolored with fixed appliances during treatment. Moreover, contemporary orthodontic composites have similar effects of enamel discoloration.

Evaluation of salivary total oxidant-antioxidant status and DNA damage of children undergoing fixed orthodontic therapy.

OBJECTIVE: To determine the total oxidant status (TOS), total antioxidant status (TAS), and the 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels and their interrelationship in the saliva of children undergoing fixed orthodontic therapy. MATERIALS AND METHODS: Thirty children were randomly divided into three groups. The attachments were bonded to all of the teeth using three different orthodontic composites: Transbond XT, Kurasper F, and GrenGloo. The salivary levels of TOS, TAS, and 8-OHdG were determined three times, as follows: before treatment (T1) and at 1 month (T2) and 3 months (T3) following appliance placement. All data were statistically analyzed. RESULTS: There were no significant differences in TOS, TAS, and 8-OHdG within the same time periods among the three different orthodontic composites (P > .05). TAS in all composite groups decreased over time. These decreases were found to be significant for Kurasper F and GrenGloo at the T1-T3 and T2-T3 time periods (P < .05). In all composite groups 8-OHdG decreased between T1 and T2 (P < .05). However, 8-OHdG in all composite groups increased from T2 to T3. These differences in 8-OHdG were significant in Kurasper F and GrenGloo (P < .05). CONCLUSIONS: Fixed orthodontic appliances bonded with the tested composites did not increase the cytotoxicity markers in saliva.

Evaluation of the genotoxicity and cytotoxicity in the buccal epithelial cells of patients undergoing orthodontic treatment with three light-cured bonding composites by using micronucleus testing.

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.

Three-dimensional imaging techniques: A literature review.

Imaging is one of the most important tools for orthodontists to evaluate and record size and form of craniofacial structures. Orthodontists routinely use 2-dimensional (2D) static imaging techniques, but deepness of structures cannot be obtained and localized with 2D imaging. Three-dimensional (3D) imaging has been developed in the early of 1990's and has gained a precious place in dentistry, especially in orthodontics. The aims of this literature review are to summarize the current state of the 3D imaging techniques and to evaluate the applications in orthodontics.

Comparison of pharyngeal airway volume among different vertical skeletal patterns: a cone-beam computed tomography study.

OBJECTIVE: To test the null hypothesis that there are no significant differences in pharyngeal airway volumes among adult patients with different vertical skeletal patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT). MATERIAL AND METHODS: The study sample consisted of 100 adult patients (45 men and 55 women; mean age  =  24.0 ± 5.3 years) with a normal sagittal skeletal pattern divided into three groups according to the vertical skeletal patterns: high angle (32 patients: 15 women and 17 men), low angle (34 patients: 14 women and 20 men), and normal angle (34 patients: 16 women and 18 men) groups. Nasopharyngeal, oropharyngeal, and total airway volumes of patients in all vertical groups were calculated. Group differences were analyzed using one-way analysis of variance and post hoc Tukey tests. RESULTS: Nasopharyngeal airway volume in the high-angle group (mean  =  6067.9 ± 1693.9 mm(3)) was significantly lower than that of the low- and normal-angle groups (P < .01). Oropharyngeal airway volume was highest in the low-angle group (mean  =  15,957.6 ± 6817.2 mm(3)) and significantly decreased in the control (mean  =  11,826.1 ± 4831.9 mm(3); P  =  .008) and high angle (mean  =  10,869.1 ± 4084.1 mm(3); P  =  .001) groups. Total airway volume was highest in the low-angle group (mean  =  24,261.6 ± 8470.1 mm(3)) and lowest in the high-angle group (mean  =  16,937.0 ± 5027.4 mm(3); P < .001). CONCLUSION: The null hypothesis was rejected. Significant differences were found in pharyngeal airway volumes among different skeletal vertical patterns.

Real-time cell analysis of the cytotoxicity of orthodontic brackets on gingival fibroblasts.

PURPOSE: The aim of this study was to evaluate the cytotoxic effects of 6 different orthodontic bracket types on human gingival fibroblasts (HGFs) using the xCELLigence system.
 METHODS: The orthodontic brackets used in this study were gold-plated steel (Apollo Gold), titanium (Rematitan), stainless steel (Equilibrium 2), lucid ice (Inspire ICE), metal-reinforced ceramic (Clarity) and composite (OrthoFlex). Gingival fibroblasts were isolated from human gingival connective tissue of systemically healthy individuals. Tested brackets were incubated in DMEM culture medium for 72 hours according to ISO 10993-5 standards. Gingival fibroblasts were maintained with Dulbecco modified Eagle medium containing 10% fetal bovine serum. The xCELLigence system was used to evaluate cell survival. The statistical analysis used was ANOVA and Tukey-Kramer multiple comparison tests.
 RESULTS: When the data were evaluated in the 30th hour, Apollo Gold showed significant decreases in cell index (P<0.001). It also showed statistically significant decreases (P<0.001) in the 65th hour, but Clarity and Inspire ICE showed significant increases in cell indices (P<0.001, P<0.01). In the 114th hour, Clarity and Equilibrium 2 showed statistically significant increases in cell indices (P<0.001). Inspire ICE and Rematitan demonstrated significant increases (P<0.05). There were significant decreases in cell index of Apollo Gold (P<0.001). 
 CONCLUSIONS: The tested brackets are suitable for clinical application, but further studies using different test methods are needed for gold-plated brackets.

Effects of low-intensity pulsed ultrasound on bone formation after the expansion of the inter-premaxillary suture in rats: a histologic and immunohistochemical study.

BACKGROUND: Orthodontic maxillary expansion is a commonly-performed treatment approach to correct transverse maxillary deficiencies by separating the mid-palatal suture. To obtain a successful treatment result and prevent relapse, the expanded maxillary sutures require maintenance by means of qualified bone reorganisation. AIM: To assess the effects of low-intensity pulsed ultrasound (LIPUS) on sutural bone formation after the expansion of the interpremaxillary suture in rats. METHODS: Sixteen male Wistar rats, 6 to 8-week old, were used. The expansion appliance comprised a helical spring fabricated from 0.014 inch stainless steel wire (Dentaurum, Ispringen, Germany). The rats were divided into two equal groups and randomly assigned to the LIPUS treatment group or a sham-operation group. LIPUS was delivered via a 2.5 cm diameter ultrasound transducer (Exogen, Smith and Nephews, Inc., Memphis, TN, USA) for 20 minutes per day during 7 days of post-expansion retention. Following retention, the rats' maxillae were surgically removed and histologic and immunohistochemical specimens were prepared and examined. RESULTS: The number of osteoblasts and blood vessel dimensions in the ultrasound group increased but was not significant, compared with the control group. A statistically significant difference in osteocalcin, VEGF and TGF-ß immunoreactivities (p < 0.01) was found in the area of the mineralising tissue. Only VEGF immunoreactivity was significant between two groups (p < 0.01) in the fibrous tissue area. CONCLUSIONS: The area of mineralising tissue in the LIPUS-applied group expressed activity markers for osteocalcin, VEGF and TGF-ß compared with a surrounding area of fibrous tissue. Cellular activation in the LIPUS group was greater than that of controls. Therefore, LIPUS may be accepted as a useful approach to enhance sutural bone formation.

Assessment of hypodontia in the Turkish patients referring to the orthodontic clinic: A retrospective study.

OBJECTIVE: The aim of this retrospective study was to assess the prevalence and distribution of hypodontia in the permanent dentition in a sample of Turkish patients who referred to the Ankara Dental Hospital for orthodontic treatment. MATERIALS AND METHODS: The pre-treatment orthodontic records of 2530 patients, 1382 girls (54.62%) and 1148 boys (45.38%) between the chronological ages of 7 and 16 years, were examined for evidence of hypodontia. The third molars were excluded in this study. RESULTS: The prevalence of hypodontia in the inspected population was 5% (3.05% for girls, 1.95% for boys). The average number of the congenitally missing teeth per patient was 2.03 (1.08 for girls, 0.95 for boys). The prevalence of the congenitally missing permanent teeth was 34% for the upper laterals, 30% for the lower second premolars, 12.5% for the upper second premolars and 23.5% for the other teeth. Most patients with hypodontia (84.9%) (57.13% for girls, 27.77% for boys) had got missing either one tooth (45.23%) or two teeth (39.67%). CONCLUSIONS: The prevalence of hypodontia in girls was higher than in boys in this sample of the Turkish patients. The upper laterals and lower second premolars were consecutively the most symmetrically absent teeth. The prevalence of advanced hypodontia was lower than single and symmetrical hypodontia.

The effects of the pendulum distalising appliance and cervical headgear on the dentofacial structures.

BACKGROUND: Headgears are effective in distalising maxillary molars, but success depends on patient compliance and tolerance. Intra-oral distalising appliances are simple to construct and use and may be a better alternative for patients who are non-compliant or cannot tolerate headgear. AIMS: To compare the Pendulum (PEN) appliance and cervical headgear (CHG) on distal movement of maxillary first molars in patients requiring maxillary molar distalisation. METHODS: Thirty patients were randomly divided into two groups. Both groups had comparable occlusal and cephalometric characteristics before treatment. Fifteen patients (9 girls, 6 boys) with a mean age of 1 1.45 +/- 1.54 years (Range: 8.58-13.50 years) were treated with Pendulum appliances and 15 patients (10 girls, 5 boys) with a mean age of 11.72 + 1.24 years (Range: 9.58-13.33 years) were treated with a Ricketts-type CHG. A pilot study of four patients estimated that the time required to distalise the maxillary molars with the Pendulum appliance was five months. Therefore, the end of treatment records for the CHG group were taken after 4.96 +/- 0.35 months. Lateral and postero-anterior cephalometric radiographs were taken of both groups at the start (T1) and end of distalisation/treatment (T2). Changes in cephalometric measurements in the two groups were compared with Wilcoxon and Mann-Whitney U tests. RESULTS: Measurements indicated that U6-ANS distance, overjet and U1-APo distance increased, U6-PP angle and U6-PTV distance reduced, and the molar relationship improved more in the PEN group compared with the CHG group. Statistically, significant right molar - left molar differences were found between the two groups. Distalisation produced significant side effects, resulting in distal tipping of the first molars and an increase in overjet, whereas the CHG reduced the overjet. CONCLUSION: The Pendulum appliance was more effective than the CHG in distalising the maxillary first molars.

Polymerization capacity of orthodontic composites analyzed by Fourier transform infrared spectroscopy.

INTRODUCTION: The aim of this in-vitro study was to analyze the polymerization capacity of 5 orthodontic composites by determining the degree of monomer conversion (DC). METHODS: Fourier transform infrared spectroscopy was used to evaluate the DC of the orthodontic composites immediately after polymerization and after storage in artificial saliva at 37°C ± 1°C for 30 days. The resin-based adhesive composites investigated were Bisco Ortho (Bisco, Schaumburg, Ill), Heliosit Orthodontics (Ivoclar, Schaan, Liechtenstein), Kurasper F (Kuraray, Okayama, Japan), Light Bond (Reliance Orthodontic Products, Itasca, Ill), and Transbond XT (3M Unitek, Monrovia, Calif), cured with Elipar FreeLight 2 (3M ESPE, St Paul, Minn) for the testing of the DC values. Fifty cylindrical specimens were manufactured in molds. The data were analyzed by 2-factor analysis of variance (ANOVA) and Tukey HSD test. RESULTS: According to 2-way ANOVA, the DC was significantly influenced by composite type (P <0.05); after 30 days, there were no differences among the composite types for the DC. The interaction of orthodontic composites and time played a statistically significant role in the DC (P <0.05), but there was no statistically significant influence of time for the DC (P >0.05). CONCLUSIONS: The DC was found to change according to composite materials used, and Bisco Ortho showed the most DC performance. The DC of orthodontic composites is a complex process that is affected not only by inorganic filler content of the composite but also the monomer type and many other factors. Sufficient DC values of 5 commercially available orthodontic composites can be achieved with a new-generation light-emitting diode curing light.