Risk assessment of external apical root resorption associated with orthodontic treatment using computed tomography texture analysis.

Objectives: This study aimed to quantitatively assess maxillary central incisor roots using pre-orthodontics computed tomography (CT) texture analysis as part of a radiomics quantitative analysis.

Methods: This retrospective case-control study included 16 patients with external apical root resorption (EARR) and 16 age- and sex-matched patients without EARR, after orthodontic treatment who underwent pre-orthodontics CT for jaw deformities. All patients were treated with a fixed orthodontic appliance before and after surgical orthodontic treatment.

Genetic contribution to palatal morphology variation using three-dimensional analysis in Australian twins.

Objective: This study aimed to provide insight into the relative contributions of genetic and environmental factors to palatal morphology variation in a cohort of Australian twins.

Methods: Healthy Australian twins, aged 12-15 years (45 monozygotic, 46 same sex dizygotic, and 32 opposite-sex dizygotic) were included in the study groups. A scanner was used to obtain three-dimensional data of the maxillary arch.

Relation of dietary preference to masticatory movement and masticatory exercises in Japanese children.

Objective: Modern Japanese children have decreased masticatory function, which can be explained by the dietary change to soft foods. In earlier studies involving children with mixed dentition, masticatory exercises were shown to improve masticatory function and modify dental arch growth. Grinding type of mastication with a wide path reportedly increases lateral growth of the dental arch.

Morphological variation in the anterior cranial fossa.

The anterior cranial fossa is an important anatomical landmark in clinical orthodontics consisting of the frontal, ethmoid, and sphenoid bones. The relationships between these bones remain poorly understood. The purposes of the present study were to describe the morphological relationships among the three bones and to discuss the factors contributing to individual variations in adult skulls based on postnatal development.

Micro-osteoperforations accelerate orthodontic tooth movement by stimulating periodontal ligament cell cycles.

Introduction: The aim of this study was to investigate the mechanism of how micro-osteoperforations (MOPs) accelerate tooth movement. We focused on inflammation, cell proliferation, and apoptosis of periodontal ligament cells and performed immunostaining of MOPs exposed to tumor necrosis factor-alpha (TNF-α), proliferating cell nuclear antigen (PCNA), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) during experimental tooth movement.

Methods: Eleven-week-old male Wistar rats were divided into 2 groups: (1) 10 g of orthodontic force applied to the maxillary first molar (TM) and (2) force application plus 3 small perforations of the cortical plate (TM + MOPs).

Effect of caspases and RANKL induced by heavy force in orthodontic root resorption.

Objective: Orthodontic root resorption (ORR) due to orthodontic tooth movement is a difficult treatment-related adverse event. Caspases are important effector molecules for apoptosis. At present, little is known about the mechanisms underlying ORR and apoptosis in the cementum.

Relationship between root resorption and individual variation in the calcium/phosphorous ratio of cementum.

Introduction: The purpose of this study was to investigate whether individual variation in the hardness and chemical composition of the cementum in the root apex affects the degree of root resorption.

Methods: In a previous study, we evaluated the Vickers hardness scale of 50 extracted teeth. For this study, we classified the 50 extracted teeth into soft, moderate, and hard groups according to the Vickers hardness scale.

Relationship between molar occlusion and masticatory movement in lateral deviation of the mandible.

Introduction: The relationship between molar occlusion and chewing patterns was examined in subjects with laterally deviated mandibles.

Methods: Twenty-three patients with mandibular deviation from the midline (4 mm or more) and skeletal Class I (0° ≤ANB ≤4°) were divided into 2 groups: normal bite and crossbite. The chewing pattern was classified as normal, reversed, or crossover.

Comparisons of orthodontic root resorption under heavy and jiggling reciprocating forces during experimental tooth movement in a rat model.

Objective: Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling.

Interleukin-17 is involved in orthodontically induced inflammatory root resorption in dental pulp cells.

Introduction: The objectives of this study were (1) to investigate the expressions of interleukin (IL)-17, RANKL (the receptor activator of NF-kappaB ligand), and osteoprotegerin (OPG) in root resorption areas during experimental tooth movement in rats, and (2) to determine the effect of IL-17 on the expressions of RANKL and OPG mRNA from human dental pulp cells.

Methods: Twelve male 6-week-old Wistar rats were subjected to an orthodontic force of 50 g to induce a mesially tipping movement of the maxillary first molars for 7 days. The expression levels of tartrate resistant acid phosphatase (TRAP), interleukin (IL)-17, IL-17 receptor (IL-17R), receptor activator of nuclear factor-kappa B ligand (RANKL), and OPG proteins were determined in dental pulp by immunohistochemical analysis.

Color stability of laboratory glass-fiber-reinforced plastics for esthetic orthodontic wires.

Objective: In our previous study, glass-fiber-reinforced plastics (GFRPs) made from polycarbonate and glass fibers were prepared for esthetic orthodontic wires using pultrusion. These laboratory GFRP wires are more transparent than the commercially available nickel-titanium wire; however, an investigation of the color stability of GFRP during orthodontic treatment is needed. Accordingly, in the present study, the color stability of GFRP was assessed using colorimetry.

Surface topography, hardness, and frictional properties of GFRP for esthetic orthodontic wires.

In our previous study, glass-fiber-reinforced plastics (GFRPs) made from polycarbonate and glass fiber for esthetic orthodontic wires were prepared by using pultrusion. The purpose of the present study was to investigate the surface topography, hardness, and frictional properties of GFRPs. To investigate how fiber diameter affects surface properties, GFRP round wires with a diameter of 0.

Preparation, mechanical, and in vitro properties of glass fiber-reinforced polycarbonate composites for orthodontic application.

Generally, orthodontic treatment uses metallic wires made from stainless steel, cobalt-chromium-nickel alloy, β-titanium alloy, and nickel-titanium (Ni-Ti) alloy. However, these wires are not esthetically pleasing and may induce allergic or toxic reactions. To correct these issues, in the present study we developed glass-fiber-reinforced plastic (GFRP) orthodontic wires made from polycarbonate and E-glass fiber by using pultrusion.

Role of interleukin-6 in orthodontically induced inflammatory root resorption in humans.

Objective: To determine the interleukin (IL)-6 levels in gingival crevicular fluid (GCF) of patients with severe root resorption after orthodontic treatment and investigate the effects of different static compressive forces (CFs) on IL-6 production by human periodontal ligament (hPDL) cells and the influence of IL-6 on osteoclastic activation from human osteoclastic precursor (hOCP) cells in vitro.

Methods: IL-6 levels in GCF samples collected from 20 patients (15 and 5 subjects without and with radiographic evidence of severe root resorption, respectively) who had undergone orthodontic treatment were measured by ELISA. The levels of IL-6 mRNA in hPDL cells and IL-6 protein in conditioned medium after the application of different uniform CFs (0, 1.

Interleukin-17/T-helper 17 cells in an atopic dermatitis mouse model aggravate orthodontic root resorption in dental pulp.

Interleukin (IL)-17 is an important mediator of orthodontically induced inflammatory root resorption (OIIRR). However, its role in the dental pulp (DP) has not been studied. The aim of this study was to investigate, using an atopic dermatitis (AD) model, how IL-17 contributes to OIIRR in DP.

Mini-implants in the anchorage armamentarium: new paradigms in the orthodontics.

Paradigms have started to shift in the orthodontic world since the introduction of mini-implants in the anchorage armamentarium. Various forms of skeletal anchorage, including miniscrews and miniplates, have been reported in the literature. Recently, great emphasis has been placed on the miniscrew type of temporary anchorage device (TAD).

Effects of relaxin on relapse and periodontal tissue remodeling after experimental tooth movement in rats.

The relapse of teeth that have moved during orthodontic treatment is a major clinical issue with respect to the goals of successful treatment. Relaxin has an influence on many physiologic processes, such as collagen turnover. In this study, we determined the effects of relaxin on the relapse and remodeling of periodontal tissue after experimental tooth movement in rats, and we explored the molecular mechanism underlying these processes.

Effects of HSP70 on the compression force-induced TNF-α and RANKL expression in human periodontal ligament cells.

Objective And Design: The aim of this study was to investigate the effect of heat shock protein 70 (HSP70) on the mRNA expression of tumor necrosis factor-alpha (TNF-α) and receptor activator of nuclear factor-kappa B ligand (RANKL) induced by compressive forces (CF) in human periodontal ligament (hPDL) cells.

Material And Treatment: hPDL cells were subjected to 1.0, 2.

Expressions of RANKL/RANK and M-CSF/c-fms in root resorption lacunae in rat molar by heavy orthodontic force.

The differentiation and functions of osteoclasts are regulated by receptor activator of nuclear factor-κB (RANK)/receptor activator of nuclear factor-κB ligand (RANKL) system that stimulates osteoclasts formation. Macrophage colony-stimulating factor (M-CSF) is also essential for osteoclastogenesis. A recent immunocytochemical study reported that RANKL/RANK and M-CSF/c-fms were localized in the periodontal ligament of rat molars during experimental orthodontic tooth movement.

Low-energy laser irradiation facilitates the velocity of tooth movement and the expressions of matrix metalloproteinase-9, cathepsin K, and alpha(v) beta(3) integrin in rats.

It has previously been reported that low-energy laser irradiation stimulated the velocity of tooth movement via the receptor activator of nuclear factor kappa B (RANK)/RANK ligand and the macrophage colony-stimulating factor/its receptor (c-Fms) systems. Matrix metalloproteinase (MMP)-9, cathepsin K, and alpha(v) beta(3) [alpha(v)beta3] integrin are essential for osteoclastogenesis; therefore, the present study was designed to examine the effects of low-energy laser irradiation on the expression of MMP-9, cathepsin K, and alpha(v)beta3 integrin during experimental tooth movement. Fifty male, 6-week-old Wistar strain rats were used in the experiment.

Associations among distributions of dental postgraduate residents, dentists and clinical training facilities in Japan.

The purpose of this study was to evaluate the correlation and distribution of dental postgraduate residents, dentists and clinical training facilities in each prefecture to analyze the regional distribution and supply of dentists in Japan. The results were also compared with referential data for medicine. The coefficient of correlation between the dentist index and dental postgraduate resident index was r = 0.

The Damon System and release of substance P in gingival crevicular fluid during orthodontic tooth movement in adults.

Metabolism by peptidases plays an important role in modulating the levels of biologically active neuropeptides. One of these neuropeptides, substance P (SP), a component of gingival crevicular fluid (GCF), may exponentiate the inflammatory process during orthodontic tooth movement. The aim of this study was to investigate the GCF levels of SP in patients using different bracket systems.

In vitro antibacterial and cytotoxicity assessments of an orthodontic bonding agent containing benzalkonium chloride.

Objective: To assess the antibacterial activity and cytotoxicity of an orthodontic bonding material containing an antibacterial agent.

Materials And Methods: Superbond C&B (4-methacryloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butyl borane [4-META/MMA-TBB]) resin was mixed with benzalkonium chloride (BAC) to obtain final BAC concentrations of 0.25%, 0.

Substance P increases production of proinflammatory cytokines and formation of osteoclasts in dental pulp fibroblasts in patients with severe orthodontic root resorption.

Introduction: The objective of this study was to determine the extent to which substance P (SP) increases proinflammatory cytokine production and osteoclast formation of human dental pulp fibroblasts (HDPF) in patients with severe orthodontically induced inflammatory root resorption (OIIRR).

Methods: HDPF were obtained from 5 patients with severe apical root resorption after orthodontic treatment. The levels of interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha were determined after 24 hours by using ELISA kits.

Effects of experimental occlusal hypofunction, and its recovery, on mandibular bone mineral density in rats.

The aim of this investigation was to examine the effects of experimental occlusal hypofunction, and recovery, on mandibular bone mineral density (BMD) using peripheral quantitative computed tomography. A metal cap was inserted between the upper and lower incisors of 40 male Wistar rats (aged 6 weeks) to prevent the molars from biting. The rats were divided into two equal groups: 'hypofunction' and 'recovery' animals.