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.

A cone-beam computed tomography evaluation of posterior available space in both arches relative to various skeletal patterns.

INTRODUCTION: This study aimed to evaluate the posterior available space (PAS) in both dental arches of adult patients with varying skeletal patterns using cone-beam computed tomography. METHODS: A sample of 114 adult patients (56 males and 58 females) was divided into 3 groups according to ANB angle and facial height ratio. Using C-mode cone-beam computed tomography images from these patients, maxillary PAS (MxPAS) and mandibular PAS (MnPAS) were measured in the distobuccal and palatal roots of the maxillary second molars and the distal roots of the mandibular second molars, respectively. The planes perpendicular to the tooth axes of the second molars in the coronal views and parallel to the posterior occlusal planes in the sagittal views were set at 3 heights of furcation, middle, and apex of the roots. For each plane, the shortest posterior distances from the roots to the inner and outer cortices were measured parallel to the furcation line connecting the furcations of the molars in the axial views. Posterior cortical bone thickness, defined as the distance from the inner cortex to the outer cortex, was measured. RESULTS: PAS was significantly greater in males than in females and in the maxilla than in the mandible (P <0.01). All MxPAS gradually increased from the furcation to the apex with significance (P <0.05), but there was no difference in MnPAS. MxPAS was significantly greater (P <0.05) in subjects with Class II and III malocclusion than subjects with Class I malocclusion, whereas MnPAS showed no difference. MxPAS showed no significant differences in facial height ratio, whereas MnPAS was significantly greater (P <0.05) at furcation in normovergent subjects than in others. Posterior cortical bone thickness was greater (P <0.001) in the mandible than in the maxilla. CONCLUSIONS: PAS was different according to sex and skeletal patterns. It would be helpful to evaluate PAS when distalizing the molars in either arch.

Hemimandibular hyperplasia treatment with condylectomy and orthodontic camouflage treatment using miniplate.

A 13-year-old growing female patient presented with hemimandibular hyperplasia of the right side, Class III hypodivergent skeletal pattern, and severe facial asymmetry. Corrective surgery was deferred until her growth had been completed. When the patient was 16 years old, a low condylectomy was performed on the hyperplastic side of her mandible to prevent its progressive condylar hyperplasia, while simultaneous orthodontic camouflage treatment was performed with the intrusion of the maxillary right posterior teeth using temporary skeletal anchorage devices without additional orthognathic surgery. A low condylectomy caused anterior and lateral open bite after the downward and backward movement of the chin, which improved Class III appearance. The intrusion of the maxillary right posterior teeth followed by compensating extrusion of the mandibular posterior teeth contributed to improve the patient's facial asymmetry with correction of the transverse occlusal plane and lip canting. After 30 months of treatment, an acceptable esthetic outcome and functional occlusion were achieved. The treatment results were well maintained for 1-year retention.

Craniomaxillofacial Changes Using High-Pull J-Hook Headgear and Mini-Implant Anchorage in Adolescents: A Structural Superimposition Method.

OBJECTIVE: The aim of this study was to compare the craniomaxillofacial changes when using high-pull J-hook headgear (HPJH) and mini-implants (MIs) as maxillary anchorage in adolescents. STUDY DESIGN: 40 female adolescents with dentoalvolar protrusion were divided into 2 groups; the HPJH group (n=20) and the MI group (n=20). Lateral cephalograms taken before treatment (T0) and after anterior tooth retraction (T1) were superimposed on the stable structures and then craniomaxillofacial changes were evaluated. RESULTS: The cranial base angle, SNB, and facial angle decreased in the HPJH group but increased in the MI group. ANB decreased more in the MI group than in the HPJH group. Mandibular plane angle increased in the HPJH group but decreased in the MI group. Facial height index increased in the MI group while it showed no change in the HPJH group. Mandibular true rotation occurred clockwise in the HPJH group and counterclockwise in the MI group. Maxillary central incisors were intruded and retracted more in the MI group than in the HPJH group. Maxillary first molars were extruded in the HPJH group and were intruded in the MI group. Maxillary first molars were protracted more in the HPJH group than in the MI group. Mandibular central incisors were retracted more in the HPJH group than the MI group. Mandibular first molars were extruded more in the MI group than in the HPJH group. CONCLUSION: More favorable craniomaxillofacial changes occurred in the MI group than in the HPJH group.

Effects of acid etching and calcium chloride immersion on removal torque and bone-cutting ability of orthodontic mini-implants.

INTRODUCTION: The 2-fold purpose of this study was to evaluate the effects of acid etching and calcium chloride immersion on removal torque and the bone-cutting ability of orthodontic mini-implants (OMIs). METHODS: For the removal torque part of the study, 3 types of OMIs (titanium alloy) were evaluated in a rabbit model: OMIs with acid surface etching with and without calcium chloride immersion (ECG and EG, respectively) and a control group (CG), in which the OMIs had an untreated, machined surface. We inserted 126 OMIs (42 OMIs per type) into both tibias of 21 male rabbits (5 months of age) with body weights of 3.0 to 3.5 kg. Removal torque was evaluated after 1, 4, and 7 weeks. To determine the OMIs' bone-cutting ability, total insertion time to place an OMI 6 mm into artificial bone was measured (6 OMIs per group). RESULTS: Removal torque values for the EG (3.97 ± 0.52 Ncm) and ECG (4.21 ± 0.44 Ncm) were statistically and significantly higher than those of the CG (3.02 ± 0.53 Ncm) 1 week after implantation (P <0.05). The ECG (6.54 ± 0.50, 6.61 ± 0.66 Ncm) showed the highest removal torque value followed by the EG (5.68 ± 0.58, 5.89 ± 0.70 Ncm) and CG (3.43 ± 0.62, 3.38 ± 0.54 Ncm) at 4 and 7 weeks after implantation (P <0.05). Removal torque did not change over time with the CG, but with the ECG and EG, it was significantly higher in weeks 4 and 7 than in week 1 (P <0.05). Total insertion time was significantly greater for the EG than for the ECG and CG (P <0.05). CONCLUSIONS: Treating OMIs with a calcium chloride solution improved the initial bone reaction by preventing contamination of the implant surface, and increasing the surface roughness of OMIs by acid etching enhanced their stability without decreasing the bone-cutting ability compared with OMIs without surface treatment.

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.

Effectiveness of pulsed electromagnetic field for pain caused by placement of initial orthodontic wire in female orthodontic patients: A preliminary single-blind randomized clinical trial.

INTRODUCTION: The purpose of this 2-arm parallel trial was to assess the effects of pulsed electromagnetic field (PEMF) on the reduction of pain caused by initial orthodontic tooth movement. METHODS: Thirty-three female patients (mean age, 16.8 ± 3.8 years) who began orthodontic treatment using fixed appliances were examined. In the pilot study, male patients were less likely to use the PEMF device (epatchQ; Speed Dental, Seoul, Korea) and answer a survey consistently, so eligibility criteria were female patients who were periodontally and systemically healthy at the initiation of treatment and had no history of dental pain in the prior 2 weeks or who used no medications (anti-inflammatory or analgesic drugs) during the experiment period. Each patient had brackets bonded on the maxillary teeth, and a 0.014-in nickel-titanium archwire was tied with elastomeric rings. Their maxillary arches were randomly divided into left and right sides in a split-mouth design: a normal PEMF device (experimental group) was used on 1 side, and a PEMF device with an inversely inserted battery (placebo group) was used on the opposite side of the arch for 7 hours on 3 consecutive nights. A Google survey link was sent to the patients' mobile phones via text message, and they were instructed to record their current pain on the survey. The survey was sent a total of 6 times after insertion of the initial archwire at 0 (T0), 2 (T1), 6 (T2), 24 (T3), 48 (T4), and 72 (T5) hours. Patients recorded the degree of pain in resting and clenching states using a numeric rating scale (NRS) from 1 (no pain) to 10 (worst pain). PEMF devices were used after T2. Generalized linear mixed models, along with ancillary pairwise analyses, were used to model and evaluate the differences in pain reported over 72 hours. RESULTS: The NRS scores did not differ across the groups during the before-PEMF phase for resting (mean difference, -0.07; 95% confidence interval [CI], -0.73 to 0.59; P = 0.842) and clenching (mean difference, -0.28; 95% CI, -1.11 to 0.56, P = 0.513). During the after-PEMF phase, NRS scores in the experimental group were significantly lower than those in the placebo group during both resting (mean difference, -1.46; 95% CI, -2.06 to -0.85; P = <0.001) and clenching (mean difference, -1.88; 95% CI, -2.74 to -1.02, P = <0.001). The NRS scores did not differ across the groups during the before-PEMF phase for either state but were significantly lower in the experimental group than in the placebo group at T3, T4, and T5 (P <0.01). The average NRS score in the clenching state was significantly greater than in the resting state. CONCLUSIONS: PEMF was effective in reducing orthodontic pain caused by initial archwire placement. REGISTRATION: The trial was not registered. PROTOCOL: The protocol was not published before trial commencement.

Forced eruption of impacted maxillary central incisors with severely dilacerated roots.

Treatment of impacted dilacerated incisors is challenging for clinicians because of the prominent position of the teeth and the abnormality of their roots. We report on 2 patients who had horizontally upward impacted and severely dilacerated maxillary central incisors. The first patient's root perforated the labial plate without significant resorption, and the second patient's root was resorbed. Both patients were treated by a surgical-orthodontic approach, and the crowns of the impacted teeth were brought into the arches by closed forced eruption. Therefore, if impacted teeth have dilacerated roots, patients should be told of the possibility of root resorption.