Evaluation of mandibular trabecular bone structure in growing children with Class I, II, and III malocclusions using fractal analysis: A retrospective study.

OBJECTIVE: The present study aimed to evaluate the mandibular bone structure of patients with different malocclusions by using fractal dimension (FD) analysis on dental panoramic radiographic images. MATERIAL AND METHODS: Pre-treatment panoramic radiographic images of 103 patients were included in the study and divided into 3 groups as Class I (group 1: 0

Third molar angulation and retromolar space after functional orthodontic treatment : Evaluation of panoramic radiographs after monoblock or Herbst appliance.

PURPOSE: The aim of this respectively cohort study was to evaluate the lower second and third molars and canine angulations, retromolar space and occlusal relationships after functional orthodontic treatments with the monoblock or Herbst appliance using panoramic radiographs. METHODS: Pre- and posttreatment cephalometric and panoramic radiographs of 133 patients (mean age 13.89 ± 1.14 years) treated non-extraction with monoblock (n: 44), Herbst (n: 45) and fixed orthodontic appliances (control group; n: 44) were included to the study. Dental and skeletal measurements were performed on cephalometric radiographs. The angle between the third and second molars, and canines with the lower border of the mandible and the occlusal plane, gonial angle, the angle between the third and second molars and the retromolar space width were assessed on pre- and posttreatment panoramic radiographs. Paired and independent t tests were used for the statistical analysis of the data for intragroup and intergroup comparisons. RESULTS: Functional treatment with both the monoblock and the Herbst appliances resulted in improvement of skeletal class II relationships. Retromolar space significantly increased in the functional appliance groups compared to the control group (p ≤ 0.001), but improvement of the angulations of posterior teeth was significant only in the monoblock group (p ≤ 0.001). CONCLUSION: While both the Herbst and monoblock appliances led to an increase in retromolar space, monoblock treatment resulted in more favorable angulation of the third molars compared to the Herbst treatment.

Effects of different distractor positions on the formation of expansion, stress and displacement patterns in surgically assisted rapid maxillary expansion without pterygomaxillary disjunction: a finite element analysis study.

Skeletal orthopedic expansion of maxilla is accepted as a reliable method for the treatment of transverse maxillar deficiency in growing patients. The aim of the study was to evaluate the effects of different palatal distractor positions on the expansion, stress and displacement patterns of the structures of craniofacial complex in surgical assisted rapid maxillary expansion without pterygomaxillary disjunction (PTMD) with the help of finite element analysis(FEA). Four facial skeleton models with different distractor positions (first premolar, second premolar, first molar, second molar regions) were created. In all finite element models median and lateral osteotomies were performed, without PTMD. Stress distribution was evaluated after 5 mm activation of the transpalatal distraction in all models using the nonlinear solution method in FEA. Unilateral displacement(mm) and stress distribution(MPa) were measured in three directions (x, y, and z axes) of craniofacial and maxillofacial structures in the symmetrical finite element models. In all models, the unilateral transverse displacements of the anterior teeth were greater than those of the posterior teeth, and the greatest displacement was at the central incisor level. The greatest displacement values at the central incisor level, at the anterior nasal spine(ANS) and at the posterior nasal spine(PNS) levels was measured in Model-IV, III, II and I, respectively. Mean elemental stress(von Mises stress) in the medial pterygoid plate, screw and lateral pterygoid plate regions from highest to lowest was measured in Model-IV, III, II and I, respectively. The maxilla performed outward rotation and tipping movement in all models during the expansion period. Among the distractor positions, the second molar region was found to be the most advantageous one in terms of expansion pattern. Considering the patient's anatomy and clinical conditions, placing the palatal distractor as posteriorly as possible will result in more effective maxillary expansion.

Effects of miniscrew-facilitated micro-osteoperforations on the rate of orthodontic tooth movement : A split-mouth, randomized controlled trial.

PURPOSE: The aim of the present split-mouth randomized controlled trial was to evaluate the effects of miniscrew-facilitated micro-osteoperforations (MOPs) on the rate of orthodontic tooth movement during canine retraction. METHODS: A total of 20 young adult patients (mean age 16.5 years) with the indication for bilateral maxillary first premolar extraction were included in the study. The MOPs were randomly applied to either the right or left side of the mouth with miniscrews (1.5 mm width, 8 mm length) to the extraction area, 28 days apart. The canine distalization continued for 3 months. The closure of the extraction space was measured by using a digital analysis program on the pre- and postdigital study models for both the control and experiment sides. RESULTS: The mean rate of extraction space closure on the MOP side was 2.51 ± 1.41 mm and on the control side was 2.88 ± 1.32 mm. There was no statistically significant difference between the groups (p > 0.05). CONCLUSION: Overall, we found that MOPs did not significantly affect the rate of orthodontic tooth movement during canine retraction.

Does puberty affect oxidative stress levels and antioxidant activity of saliva in patients with fixed orthodontic appliances?

PURPOSE: To evaluate and compare patients' oxidative stress parameters and antioxidant status with fixed orthodontic appliances during the pubertal and postpubertal growth periods. METHODS: Saliva samples of 20 pubertal (mean age: 12.94 ± 0.34 years) and 20 postpubertal (mean age: 16.34 ± 0.45 years) patients were collected just before the application of fixed orthodontic appliances (T0), 4-5 h (T1), and 7 days (T2) after the initial orthodontic activation. Myeloperoxidase (MPO), nitric oxide (NO), 8­hydroxydeoxyguanosine (8-OHdG) levels, and superoxide dismutase (SOD) activity in the saliva were examined. Repeated measures analysis of variance (ANOVA), least significant difference (LSD) pairwise comparison, and independent sample t­tests were used to analyze the differences between the time points and growth periods, respectively. RESULTS: MPO levels in the saliva of patients in the pubertal period showed a significantly higher increase within the first days of treatment (T2-T1) than in patients in the postpubertal period (p < 0.05). The SOD antioxidant enzyme activity decreased in the samples from T0 to T1 in the patients in the pubertal and postpubertal groups and returned to baseline values (T0) at T2 (p < 0.01). No significant differences in the other biochemical parameters between groups were observed. CONCLUSIONS: Comparing the pubertal and postpubertal groups, orthodontic force application with fixed orthodontic appliances did not change the final levels (on day 7) of antioxidant status or oxidative stress markers, except for MPO in saliva.

Effects of functional orthopedic treatment on mandibular trabecular bone in class II patients using fractal analysis.

PURPOSE: The aim of this retrospective study was to evaluate the effects of functional orthopedic treatment on mandibular bone structure using fractal dimension (FD) analysis of panoramic radiographs. METHODS: The study material consisted of the pre- and posttreatment digital panoramic radiographs of 80 patients (mean age 10.1 ±â€¯2.01 years; 45 girls, 35 boys) with class II malocclusion who were treated with the monoblock or twin block appliances. The following regions of interest (ROI) were selected: ROI1, condylar process; ROI2, angulus mandibulae; ROI3, corpus mandibulae; and ROI4, mental foramen. Pre- and posttreatment FD values were compared for each ROI. RESULTS: FD values of the mandibular condyle did not change with the functional orthodontic treatment. FD values of the mandibular corpus region had the highest pretreatment values and significantly decreased with treatment (p < 0.05). CONCLUSION: Functional orthopedic treatment altered the trabeculation of the mandibular bone, but it is speculated that the changes in the occlusal forces seemed to be of primary significance for this effect.

Microleakage beneath orthodontic brackets in high field magnetic resonance imaging (MRI) AT 1.5 & 3 Tesla.

OBJECTIVES: The aim of the present study was to evaluate the effects of 1.5 T and 3 T MRI on the adhesion between the orthodontic brackets and the teeth by evaluating the microleakage between the enamel, adhesive and brackets interfaces. METHODS: 58 extracted human premolars which were received a standard bracket bonding procedure were randomly divided into three groups; control group (n = 20; no MRI), 1.5 T MRI group (n = 19; 20 min MRI exposure of 1.5 T) and 3 T MRI group (n = 19; 20 min MRI exposure of 3 T). The teeth were kept in distiled water for 2 weeks, and thereafter subjected to 500 thermal cycles. Then, specimens were sealed with nail varnish, stained with 0.5% basic fuchsin for 24 h, sectioned and photographed under a stereomicroscope. Microleakage was scored with regard to the adhesive-enamel and bracket-adhesive interfaces at the occlusal and gingival levels. Statistical analysis was accomplished by Kruskal-Wallis and Bonferroni-Dunn tests. RESULTS: All of the groups exhibited statistically similar microleakage scores in the adhesive-enamel interface along occlusal margins (p>0.05, p = 0.331). The mean microleakage scores along gingival margins in the 3 T MRI group was significantly higher compared to the control group both in the adhesive-enamel and bracket-adhesive interfaces (p<0.05, p = 0.019 and p = 0.020 respectively). The microleakage scores along the gingival margins were also significantly higher than the occlusal margins in the 3 T MRI group (p<0.05, p = 0.029). CONCLUSIONS: 3 T MRI may weaken the adhesion between the enamel and the stainless steel orthodontic brackets.

External apical root resorption after orthodontic treatment: Incidence, severity and risk factors.

Background. This study aimed to evaluate the incidence and severity of orthodontically induced inflammatory external apical root resorption (OIIEARR) and the relationship between OIIEARR and possible risk factors such as orthodontic treatment type, treatment duration, gender, and age of the patients. A further aim was to determine the prevalence of OIIEARR in different tooth groups. Methods. The study sample consisted of 1356 orthodontically treated patients (857 females and 498 males; mean age: 14.4±2.8 years). OIIEARR was evaluated using pre- and post-treatment panoramic radiographs for all the tooth groups. Teeth with severe resorption were also assessed. Patient- and treatment-related risk factors for OIIEARR were assessed statistically using Pearson's chi-squared test, independent-samples t test, and one-way ANOVA. Results. The incidence of severe root resorption following orthodontic treatment was 14.8%. Males exhibited a higher incidence of root resorption compared to females. Orthodontic treatment duration and treatment with extractions were positively correlated with OIIEARR (P < 0.05). OIIEARR was observed most frequently in maxillary incisors, followed by mandibular incisors. Conclusion. Orthodontic treatment with extraction, prolonged treatment duration, and large movements of the incisors should especially be taken into consideration for OIIEARR risk. Routine radiographic follow-up during orthodontic treatment is recommended.

Comparison of intraoperative volume and pressure-controlled ventilation modes in patients who undergo open heart surgery.

Respiratory problems occur more frequently in patients who undergo open heart surgery. Intraoperative and postoperative ventilation strategies can prevent these complications and reduce mortality. We hypothesized that PCV would have better effects on gas exchange, lung mechanics and hemodynamics compared to VCV in CABG surgery. Our primary outcome was to compare the PaO2/FiO2 ratio. Patients were randomized into two groups, (VCV, PCV) consisting of 30 individuals each. Two patients were excluded from the study. I/E ratio was adjusted to 1:2 and, RR:10/min fresh air gas flow was set at 3L/min in all patients. In the VCV group TV was set at 8 mL/kg of the predicted body weight. In the PCV group, peak inspiratory pressure was adjusted to the same tidal volume with the VCV group. PaO2/FiO2 was found to be higher with PCV at the end of the surgery. Time to extubation and ICU length of stay was shorter with PCV. Ppeak was similar in both groups. Pplateau was lower and Pmean was higher at the and of the surgery with PCV compared to VCV. The hemodynamic effects of both ventilation modes were found to be similar. PVC may be preferable to VCV in patients who undergo open heart surgery. However, it would be convenient if our findings are supported by similar studies.

A new method for epidural catheter fixation.

We investigated the effect of a new fixator made from a medication port of a intravenous fluid container on the migration of epidural catheter. Fifty patients were recruited to receive epidural analgesia and allocated to one of two groups. In the new fixator group (n=25) epidural catheter was advanced through a fixator then fixed with transparent adhesive dressing, in the standard dressing group (n=25), the catheter was fixed only with transparent adhesive dressing. Outward migration of the catheter over 2 cm, and inward migration over 1 cm was described as the failure of the fixation. At the end of the follow up time, outward migration or inward migration distance, and the reason for removing the catheter were recorded. In the standard dressing group, outward migration was detected in 7 patients compared to 2 patients in the new fixator group (p>0.05). Inward migration was determined in only 5 cases in the standard dressing group (p<0.05). There was no movement in 13 cases in the standard dressing group compared with 23 of the new fixator group (p<0.05). The main reason for removal in the standard dressing group was the migration of the catheter whereas the catheter was removed on a regular basis at the end of therapy in the new fixator group. We concluded that the newly described fixation method for epidural catheter is an effective method in reducing catheter migration for short term usage.