A finite element analysis of stress distribution with various directions of intermaxillary fixation using orthodontic mini-implants and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy.

OBJECTIVE: This finite element analysis (FEA) aimed to assess the stress distribution in the mandible and fixation system with various directions of the intermaxillary fixation (IMF) using mini-implants (MIs) and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy (BSSRO). MATERIALS AND METHODS: A total of nine mandibular advancement models were set according to the position of the MIs (1.6 mm in diameter, 8 mm in length) and direction of the IMF elastics (1/4 inch, 5 oz). Major and minor principal stresses in the cortical and cancellous bones, von Mises stresses in the fixation system (miniplate and monocortical screws), and bending angles of the miniplate were analysed. RESULTS: Compressive and tensile stress distributions in the mandible and von Mises stress distributions in the fixation system were greater in models with a Class III IMF elastic direction and a higher IMF elastic force than in models with a Class II IMF elastic direction and a lower IMF elastic force. The bending angle of the miniplate was negligible. CONCLUSIONS: Stress distributions in the bone and fixation system varied depending on the direction, amount of force, and position of IMF elastics and MIs. Conclusively, IMF elastics in the Class II direction with minimal load in the area close to the osteotomy site should be recommended.

Interdisciplinary treatment of mutilated dentition and transverse maxillary deficiency with microimplant-assisted rapid palatal expansion, microimplants, and dental implants.

OBJECTIVE: This case report demonstrates an interdisciplinary approach to treat a 26-year-old male patient with hyperdivergent Class II skeletal pattern, maxillary transverse deficiency, slight anterior open bite, and multiple hopeless teeth with root rests. CLINICAL CONSIDERATIONS: An interdisciplinary treatment was required for oral hygiene improvement, caries treatment, extraction of residual roots and hopeless teeth, maxillary expansion using microimplant-assisted rapid palatal expansion, improvement of skeletal and dental relationship using orthodontic microimplants, and prosthetic restorations with the aid of dental implants. CONCLUSION: Consequently, esthetic and functional occlusal rehabilitation was achieved. CLINICAL SIGNIFICANCE: Hyperdivergent Class II facial and skeletal patterns with multiple missing teeth can be effectively treated using orthodontic skeletal anchorage. In young adults, the transverse discrepancy can be resolved using MARPE, which is also useful for improving the sagittal and vertical relationships. In the case of multiple missing teeth, orthodontic treatment can provide the proper space to facilitate dental implants to achieve optimal esthetics and function.

Interdisciplinary treatment of a mutilated dentition with multiple missing teeth and horizontal impaction of a mandibular third molar using an orthodontic skeletal anchorage and dental implants-Case report.

OBJECTIVE: This case report presents a female adult patient who exhibits poor oral hygiene, a mutilated dentition with multiple missing teeth, and skeletal asymmetry. CLINICAL CONSIDERATIONS: Interdisciplinary treatment was necessary to maintain oral hygiene, treat caries, extract residual roots, and upright a horizontally impacted third molar using a miniplate. Additionally, orthodontic mini-implants were utilized as anchorage to improve sagittal relationship and space closing. Space management was completed with orthodontic treatment, followed by restoration of the multiple missing teeth with dental implants. CONCLUSION: Consequently, an esthetic smile and functional occlusion were achieved by interdisciplinary treatment using orthodontic skeletal anchorage devices and dental implants. CLINICAL SIGNIFICANCE: Missing mandibular first molar spaces were closed with retraction of the anterior teeth and protraction of the mandibular second molars using orthodontic mini-implants. The mandibular right third molar, which should have erupted, was protracted with the second molar, while the horizontally impacted mandibular left third molar was uprighted using a miniplate and was protracted with an orthodontic mini-implant. The missing maxillary lateral incisors were replaced with the maxillary canines, and the maxillary canines were replaced with the maxillary first premolars. The missing maxillary right second premolar and first molar and left first and second molars were successfully restored with dental implants.

Class II Division 1 Adolescent Treatment with Twin Block and Fixed Orthodontic Appliances: 3-Dimensional Changes of the Temporomandibular Joint.

INTRODUCTION: Skeletal Class II division 1 malocclusions with a retrognathic mandible can be treated with Twin Block and fixed orthodontic appliances in growing adolescent patients. OBJECTIVE: The aim of this case report was to show successful treatment results following step-by-step procedures determined by visualizing the changes of the temporomandibular joint (TMJ) area using cone-beam computed tomography (CBCT) images. CASE REPORT: A 10-year, 8-month-old female adolescent with skeletal Class II division 1 (ANB, 6.2°), severe overjet (8.4 mm), and overbite (7.8 mm) was treated with Twin Block and fixed orthodontic appliances. After wearing an active plate for 4 months, a Twin Block appliance for 9 months, a retainer with an inclined plane for 13 months, and fixed orthodontic treatment for 17 months, her skeletal Class II was corrected. After 39 months of posttreatment retention, good treatment results were maintained with favorable occlusion and facial balance. Acceptable 3-dimensional changes of the TMJ area were identified using cone-beam computed tomography images. CONCLUSION: A female adolescent patient with skeletal Class II division 1 malocclusion, severe overjet and overbite, and mandibular retrusion was treated using Twin Block and fixed orthodontic appliances. Acceptable 3-dimensional changes in the TMJ area and 2-dimensional growth of the mandible were identified using CBCT and cephalometric images.

Mandibular condyle bone density in adolescents with varying skeletal patterns evaluated using cone-beam computed tomography: A potential predictive tool.

INTRODUCTION: The aim of this study was to evaluate the bone density of mandibular condyles in adolescents with varying skeletal patterns using cone-beam computed tomography. The null hypothesis was that there is no difference in the bone density of mandibular condyles in adolescents across various facial height ratios, ANB angle classifications, sexes, and age categories. METHODS: We divided 120 adolescent patients, 56 boys and 64 girls, into 3 groups according to 3 criteria: (1) age (early, 10 to <14 years; middle, 14 to <17 years; late, 17 to <20 years); (2) facial height ratio or Jarabak quotient (hyperdivergent: facial height ratio, <62%; normovergent: facial height ratio, 62% to ≤65%; and hypodivergent: facial height ratio, >65%); and (3) ANB angle classification (Class I, 1° to ≤4°; Class II, (>4°); and Class III, <1°). The total, cortical, and cancellous bone densities were measured and compared on the axial slice with the largest mediolateral diameter of the mandibular condyle using C-mode cone-beam computed tomography. RESULTS: Cortical bone density increased as age increased and showed statistically significant differences between the early and middle (P = 0.041) and the early and late adolescent groups (P = 0.031). Condylar bone density increased as facial height ratio decreased, and cancellous bone density showed statistically significant differences between the hyperdivergent and hypodivergent groups (P = 0.038). The cortical, cancellous, and total bone densities increased as ANB angle increased and showed statistically significant differences between the Class II and Class III groups (P = 0.022, P = 0.006, and P = 0.003, respectively). CONCLUSIONS: The null hypothesis was rejected. Condylar bone density increased as facial height ratio decreased and ANB angle increased. These findings may be useful in predicting the vertical and horizontal skeletal growth patterns of growing adolescents.

Forced eruption of a palatally impacted and transposed canine with a temporary skeletal anchorage device.

Treatment of palatally impacted and transposed canines is challenging for both orthodontists and oral surgeons. To treat a maxillary canine impaction without risking damage to adjacent teeth, it is necessary to use cone-beam computed tomography for proper localization and treatment planning. In this case report, a palatally impacted canine was initially retracted distally with a microimplant inserted in the palatal slope and then was moved buccally into its ideal position. The patient's occlusion and smile esthetics were significantly improved after orthodontic treatment.

Bone density effects on the success rate of orthodontic microimplants evaluated with cone-beam computed tomography.

INTRODUCTION: The purpose of this study was to evaluate the effect of bone densities on the success rate of orthodontic microimplants with cone-beam computed tomography images. METHODS: We examined 127 orthodontic microimplants implanted into the maxillary buccal alveolar bone of 71 patients (53 female, 18 male; mean age, 19.2 years) with malocclusion. The cortical, cancellous, and total bone densities were measured with Simplant Pro 2011 software (version 13; Materialise, Leuven, Belgium), and the correlations between these measurements and the orthodontic microimplant success rates were evaluated with cone-beam computed tomography. RESULTS: The overall success rate was 85.0% (108 of 127). Sex, age, and side of placement were not significant factors for success in the results (P >0.05). The density of the cortical bone increased apically (3, 5, and 7 mm) from the alveolar crest, but in the cancellous bone it decreased. Whereas the orthodontic microimplant success rates significantly increased as cancellous bone density and total bone density increased (P <0.01), cortical bone density did not have a significant effect on the success rate (P >0.05). CONCLUSIONS: The success rate of orthodontic microimplants significantly increased with higher cancellous and total bone densities, whereas cortical bone density did not have a significant effect.

Orthodontic Treatment of Maxillary Incisors with Severe Root Resorption Caused by Bilateral Canine Impaction in a Class II Division 1 Patient.

This case report shows the successful alignment of bilateral impacted maxillary canines. A 12-year-old male with the chief complaint of the protrusion of his maxillary anterior teeth happened to have bilateral maxillary canine impaction on the labial side of his maxillary incisors. Four maxillary incisors showed severe root resorption because of the impacted canines. The patient was diagnosed as skeletal Class II malocclusion with proclined maxillary incisors. The impacted canine was carefully retracted using sectional buccal arch wires to avoid further root resorption of the maxillary incisors. To distalize the maxillary dentition, two palatal miniscrews were used. After 25 months of treatment, the maxillary canines were well aligned without any additional root resorption of the maxillary incisors.

Assessment of bone density changes following two-jaw surgery using multidetector computed tomography: A pilot study.

OBJECTIVE: The aim of this retrospective study was to evaluate the pre- and postsurgical bone densities at alveolar and extra-alveolar sites following twojaw orthognathic surgery. METHODS: The sample consisted of 10 patients (mean age, 23.2 years; range, 18.0-27.8 years; 8 males, 2 females) who underwent two-jaw orthognathic surgery. A three-dimensional imaging program (Invivo 5) was used with multidetector computed tomography images taken preand postoperatively (obtained 32.3 ± 6.0 days before surgery and 5.8 ± 2.6 days after surgery, respectively) for the measurement of bone densities at the following sites: (1) alveolar bone in the maxilla and mandible, (2) extra-alveolar sites, such as the top of the head, menton (Me), condyle, and the fourth cervical vertebrae (C4). RESULTS: When pre- and postsurgical bone densities were compared, an overall tendency of decrease in bone density was noted. Statistically significant reductions were observed in the densities of cancellous bone at several areas of the maxillary alveolar bone; cortical and cancellous bone in most areas of the mandibular alveolar bone; cortical bone in Me; and cancellous bone in C4. There was no statistically significant difference in bone density in relation to the depth of the alveolar bone. In a comparison of the bone densities between groups with and without genioplasty, there was almost no statistically significant difference. CONCLUSIONS: Accelerated tooth movement following orthognathic surgery may be confirmed with reduced bone density. In addition, this study could offer insights into bone metabolism changes following orthognathic surgery, providing direction for further investigations in this field.

Evaluation of hydrogen production and internal resistance in forward osmosis membrane integrated microbial electrolysis cells.

In order to enhance hydrogen production by facilitated proton transport through a forward osmosis (FO) membrane, the FO membrane was integrated into microbial electrolysis cells (MECs). An improved hydrogen production rate was obtained in the FO-MEC (12.5±1.84×10(-3)m(3)H2/m(3)/d) compared to that of the cation exchange membrane (CEM) - MEC (4.42±0.04×10(-3)m(3)H2/m(3)/d) during batch tests (72h). After an internal resistance analysis, it was confirmed that the enhanced hydrogen production in FO-MEC was attributed to the smaller charge transfer resistance than in the CEM-MEC (90.3Ω and 133.4Ω respectively). The calculation of partial internal resistance concluded that the transport resistance can be substantially reduced by replacing a CEM with a FO membrane; decrease of the resistance from 0.069Ωm(2) to 5.99×10(-4)Ωm(2).

Polydopamine coating effects on ultrafiltration membrane to enhance power density and mitigate biofouling of ultrafiltration microbial fuel cells (UF-MFCs).

Membrane resistance is due to the low accessibility of liquid electrolytes onto the membrane surface; resultant membrane biofouling lowers the power generation capacity of microbial fuel cells (MFCs). In this study, in order to reduce membrane resistance caused by migrative ion transport resistance and membrane biofouling, a polydopamine (PD) coating was adopted for the modification of ultrafiltration (UF) membrane surfaces in UF membrane integrated MFCs (UF-MFCs). After a PD coating was applied to a UF membrane, the contact angle measured on the support layer of a UF membrane decreased and the membrane surface charge became negative. The maximum power density of UF-MFC increased after the PD coating on a UF membrane and a remarkable reduction of charge transfer resistance was observed using electrochemical impedance spectroscopy (EIS) analysis. Lower extracellular polymeric substance (EPS) concentrations and total cell numbers were observed on the PD coated UF membrane surface after 72 h operation, although 17% of a permeate flux of UF-MFC decreased after PD coating.

Small airway-centered granulomatosis caused by long-term exposure to polytetrafluoroethylene.

To date, there have been no reports of chronic pulmonary granulomatosis associated with exposure to polytetrafluoroethylene (PTFE). Here, we report three cases of small airway-centered granulomatous lesions in workers employed at facilities that apply coatings to pans and other utensils. The workers were repeatedly exposed to PTFE particles that were probably generated by the drying process when PTFE coatings are dried in a convection oven at high temperatures (380-420 °C). The duration of inhalational PTFE exposure was between 7 and 20 years. We found granulomatous lung lesions around the small airways in lung biopsy specimens obtained from the workers. Scanning electron microscopy/energy-dispersive x-ray spectroscopy analysis was performed focusing on areas where the PTFE particles were suspected to be located in macrophages. The scanning electron microscopy/energy-dispersive x-ray spectroscopy analyses revealed fluorine in the particles. Lung tissue samples from all cases were analyzed using a fully automated Fourier transform infrared spectrometer. Analysis of the spectrum extracted from the position of the foreign particles enabled precise identification of the foreign bodies as PTFE. Fourier transform infrared revealed that all of the lung tissue samples had bands at 1,202 to 1,148 cm(-1) and 1,202 to 1,146 cm(-1), which are characteristic of the asymmetric and symmetric stretching vibrations of the C-F bonds of PTFE. These cases suggest that recurrent inhalational exposure to PTFE particles causes chronic pulmonary granulomatosis.

[A case of bacteremia by Atopobium rimae in a patient with liver cirrhosis].

Atopobium rimae, previously Lactobacillus rimae, is a strictly anaerobic, non-spore forming grampositive rod which was frequently isolated from odontogenic infection. We report a case of A. rimae bacteremia. A 47-yr-old man with liver cirrhosis was admitted to the hospital via emergency room due to fever and chill. His abdominal and pelvic computed tomography revealed a small abscess near the left adrenal gland. Three sets of blood cultures were taken and non-spore forming, grampositive rods were detected in all anaerobic vials. This isolate grew small nonhemolytic, gray-white translucent colonies on Brucella blood agar and was obligatory anaerobic on air-tolerance test. This organism was negative for catalase, indole, nitrate-reduction and beta-lactamase and failed to identify by Vitek ANI card (bioMerieux, France). 16S rRNA sequences of this showed 99.8% homology of the published sequence of A. rimae (GenBank accession number AF292371). Aspirates of periadrenal abscess grew Escherichia coli and Peptostreptococcus micros. He was treated with metronidazole and imipenem and follow-up cultures of blood were negative at days 4 and 10. To our knowledge, this is the first report of bacteremia of A. rimae.