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1.
Bone ; 138: 115497, 2020 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-32599221

RESUMO

Adult bone homeostasis requires a fine-tuned balance between the activity of osteoblasts and osteoclasts. This osteoblast-osteoclast coupling is therapeutically important because it limits the efficacy of most anabolic or anti-resorptive treatments for osteoporosis. Sirtuin6 (SIRT6), a histone deacetylase, was implicated recently as an important regulator in bone homeostasis, but its in vivo function in osteoblast lineage cells remains unclear, mainly due to a lack of in vivo experiments with osteoblast lineage-specific Sirt6 knockout mice. Here, we show that Sirt6 in mature osteoblasts and/or osteocytes inhibits osteoclastogenesis via a paracrine mechanism. We found that osteoblast/osteocyte-specific Sirt6 knockout mice show reduced bone mass due to increased osteoclast formation. Mechanistically, we attribute this increased osteoclastogenesis to decreased osteoprotegerin expression in Sirt6-null osteoblasts and osteocytes. This loss of Sirt6 in osteoblasts and osteocytes does not, however, alter bone formation parameters in vivo. It does accelerate osteogenic differentiation in ex vivo culture, indicating that the osteoblast/osteocyte-autonomous functions of SIRT6 have minor effects on the osteopenic phenotype. These results establish a critical role for SIRT6 in mature osteoblasts and osteocytes in adult bone homeostasis as a negative paracrine regulator of osteoclastogenesis.

2.
Am J Orthod Dentofacial Orthop ; 157(6): 843-851, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32487314

RESUMO

INTRODUCTION: The registration of cone-beam computed tomography (CBCT) images and digital dental models is required for the design and manufacturing of dental devices such as implant guides and surgical wafers. This study aims to register intraoral scan (IS) models and cast scan (CS) models onto CBCT images using 3-dimensional (3D) planning software and evaluate the registration accuracy according to scanning methods and 3D planning software. METHODS: The CBCT image of an artificial skull model with reference markers was taken. The CS model and the IS model were obtained from the same skull model, registered onto the CBCT image using 3D planning software packages providing manual registration (MR) function and point-based registration (PR) functions, and set as the experimental groups. After registration, shell to shell deviations and positional differences between the reference model and the experimental models were evaluated. RESULTS: The shell to shell deviations ranged from 0.03 to 0.18 mm. Deviations in both the maxilla and mandible were significantly different according to scanning methods and software packages. In the anteroposterior direction, the IS-MR and CS-MR groups showed significantly different positions. In the superoinferior direction, the MR and PR groups showed significantly different positions. CONCLUSIONS: The registration using the PR function of the 3D planning software packages was significantly more accurate than the registration using the MR function. There was no significant difference between the registrations using the IS model and the CS model when using the PR functions.

3.
Korean J Orthod ; 49(6): 360-371, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31815104

RESUMO

Objective: We sought to determine the predictors of midpalatal suture expansion by miniscrew-assisted rapid palatal expansion (MARPE) in young adults. Methods: The following variables were selected as possible predictors: chronological age, palate length and depth, midpalatal suture maturation (MPSM) stage, midpalatal suture density (MPSD) ratio, the sella-nasion (SN)-mandibular plane (MP) angle as an indicator of the vertical skeletal pattern, and the point A-nasion-point B (ANB) angle for anteroposterior skeletal classification. For 31 patients (mean age, 22.52 years) who underwent MARPE treatment, palate length and depth, MPSM stage and MPSD ratio from the initial cone-beam computed tomography images, and the SN-MP angle and ANB angle from lateral cephalograms were assessed. The midpalatal suture opening ratio was calculated from the midpalatal suture opening width measured in periapical radiographs and the MARPE screw expansion. Statistical analyses of correlations were performed for the entire patient group of 31 subjects and subgroups categorized by sex, vertical skeletal pattern, and anteroposterior skeletal classification. Results: In the entire patient group, the midpalatal suture opening ratio showed statistically significant negative correlations with age, palate length, and MPSM stage (r = -0.506, -0.494, and -0.746, respectively, all p < 0.01). In subgroup analyses, a strong negative correlation was observed with the palate depth in the skeletal Class II subgroup (r = -0.900, p < 0.05). Conclusions: The findings of this study indicated that age, palate length, and MPSM stage can be predictors of midpalatal suture expansion by MARPE in young adults.

4.
Korean J Orthod ; 49(5): 319-325, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31598488

RESUMO

Objective: To evaluate differences in skeletal maturity in relation to vertical facial types and to compare differences in the skeletal maturity of the cervical vertebrae and hand-wrist in females. Methods: This study included 59 females aged 7 to 9 years with skeletal Class I malocclusion. The participants were categorized into three groups (low, normal, and high) according to the mandibular plane angle. Skeletal maturity was measured using skeletal maturity indicators (SMIs) and the Tanner-Whitehouse III (TW3) method on hand-wrist radiographs and by using cervical vertebrae maturation indicators (CVMIs) on lateral cephalometric radiographs. Results: The SMI was higher in the high-angle group than in the low-angle group (p = 0.014). The median TW3 bone age was 11.4 months higher in the high-angle group than in the low-angle group (p = 0.032). There was no significant difference in CVMI among the three groups. Skeletal maturity showed a weakly positive correlation with the mandibular plane angle (SMI, r = 0.391; TW3, r = 0.333; CVMI, r = 0.259). Conclusions: The skeletal maturity of the hand-wrist in females with a high mandibular plane angle was higher than that in females with a low mandibular plane angle. Obtaining additional hand-wrist radiographs may facilitate evaluation of skeletal maturity of females. In females with a high mandibular angle, the time to commence orthodontic treatment may be earlier than that in females with a low mandibular angle.

5.
Mater Sci Eng C Mater Biol Appl ; 105: 110049, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546363

RESUMO

The aim of this study was to evaluate whether combining two treatments to avoid biological aging of the surface of titanium and zirconia implants; i.e., storage in an aqueous solution after ultraviolet light (UV) or non-thermal atmospheric pressure plasma (NTP) treatment, yielded surface bioactivity comparable to that following post-15-min UV or NTP treatment storage under air or immediately after UV or NTP treatment. Grade IV titanium discs modified by large grit sand-blasting and acid-etching (SLA) and smooth zirconia discs were irradiated with UV or NTP and their surface properties were evaluated immediately and after storage for 8 weeks in distilled H2O (dH2O) and a sealed container under air. Approximately 15-30 nm-sized nano-protrusions were formed only on SLA surfaces in dH2O immediately after UV or NTP treatment. Immediate dH2O storage after UV or NTP treatment prevented hydrocarbon contamination and maintained elevated amounts of Ti and Zr. After 8 weeks, unlike zirconia, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on SLA surfaces stored in dH2O immediately after UV treatment were further exceeding those immediately after UV or NTP treatments. UV treatment of SLA implants followed by wet storage can not only maintain but also strengthen bioactivity during shelf storage.


Assuntos
Implantes Experimentais , Teste de Materiais , Gases em Plasma/química , Titânio , Raios Ultravioleta , Zircônio , Animais , Pressão Atmosférica , Linhagem Celular , Camundongos , Propriedades de Superfície , Titânio/química , Titânio/farmacologia , Zircônio/química , Zircônio/farmacologia
6.
Am J Orthod Dentofacial Orthop ; 156(3): 365-374, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31474266

RESUMO

INTRODUCTION: We sought the 3-dimensional (3D) zone of the center of resistance (ZCR) of mandibular posterior teeth groups (group 1: first molar; group 2: both molars; group 3: both molars and second premolar; group 4: both molars and both premolars) with the use of 3D finite element analysis. METHODS: 3D finite element models comprised the mandibular posterior teeth, periodontal ligament, and alveolar bone. In the symmetric bilateral model, a 100-g midline force was applied on a median sagittal plane at 0.1-mm intervals to determine the anteroposterior and vertical positions of the ZCR (where the applied force induced translation). The most reliable buccolingual position of the ZCR was then determined in the unilateral model. The combination of the anteroposterior, vertical, and buccolingual positions was defined as the ZCR. RESULTS: The ZCRs of groups 1-4 were, respectively, 0.48, 0.46, 0.50, and 0.53 of the mandibular first molar root length from the alveolar crest level and located slightly distobuccally at anteroposterior ratios of 2:3.0, 2:2.3, 2:2.4, and 2:2.5 to each sectional arch length and at buccolingual ratios of 2:1.5, 2:1.1, 2:1.6, and 2:2.4 to the first molar's buccolingual width. CONCLUSIONS: The ZCR can be a useful reference for 3D movement planning of mandibular posterior teeth or segments.


Assuntos
Imageamento Tridimensional/métodos , Mandíbula/anatomia & histologia , Mandíbula/diagnóstico por imagem , Dente/anatomia & histologia , Dente/diagnóstico por imagem , Processo Alveolar/anatomia & histologia , Processo Alveolar/diagnóstico por imagem , Dente Pré-Molar/anatomia & histologia , Dente Pré-Molar/diagnóstico por imagem , Arco Dental , Modelos Dentários , Análise de Elementos Finitos , Humanos , Dente Molar/anatomia & histologia , Dente Molar/diagnóstico por imagem , Ortodontia Corretiva , Ligamento Periodontal/anatomia & histologia , Ligamento Periodontal/diagnóstico por imagem , Técnicas de Movimentação Dentária
7.
Am J Orthod Dentofacial Orthop ; 156(3): 375-382, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31474267

RESUMO

INTRODUCTION: The aim of this work was to compare the skeletal and dental outcomes of 1- versus 2-phase treatment in Class II subjects with difficult-to-treat high-angle severe Class II malocclusions. METHODS: The sample of 120 cases was collected from the private offices of 3 experienced clinicians. The following selection criteria were used: (1) ANB ≥6°, (2) SN-GoGn ≥37° or mandibular plane to Frankfort horizontal plane ≥30°; and (3) overjet ≥6 mm. Patients were classified into either the early or the late treatment group according to dental age (early Tx: ≥5 primary teeth; late Tx: otherwise). Thirty-four angular, linear, and proportional measurements were determined for each patient. Statistical significance was assessed with the use of a 2-tailed t test, analysis of covariance test, and chi-square test. RESULTS: The results showed that early 2-phase treatment for severe Class II high-angle patients offered no skeletal anteroposterior advantages over late 1-phase treatment. Severe high-angle Class II patients also showed similar dental anteroposterior outcomes with the use of both approaches. Vertically there was a higher frequency of increased mandibular plane angles and extrusion of upper incisors and lower molars in the late treatment group. CONCLUSIONS: Early 2-phase treatment for severe Class II high-angle patients offered no skeletal or dental advantage over late 1-phase treatment.


Assuntos
Má Oclusão de Angle Classe II/terapia , Ortodontia Corretiva/métodos , Adolescente , Cefalometria/métodos , Criança , Feminino , Humanos , Incisivo , Masculino , Mandíbula , Maxila , Dente Molar , Sobremordida/terapia , Fatores de Tempo , Resultado do Tratamento
8.
Dent Mater ; 35(9): 1331-1341, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31320183

RESUMO

OBJECTIVE: This study evaluated the synergetic effect between surface pre-reacted glass-ionomer (SPRG) filler and 2-methacryloyloxyethyl phosphorylcholine (MPC), for inhibiting multi-species biofilm formation, while maintaining or even improving the original beneficial features of SPRG-filled resin-based composite (RBC). METHODS: MPC (1.5-10wt%) was incorporated into commercial SPRG-filled RBC. Then, the inherent properties of RBC, and ion release and acid-neutralising properties associated with SPRG were investigated. Further, protein adsorptions and bacterial adhesion and viability on the SPRG-filled RBC surfaces were studied using four kinds of oral bacteria; Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, and Porphyromonas gingivalis. Finally, the thickness and biomass of the human saliva-derived biofilm model cultured on test and control samples were analysed. RESULTS: Addition of MPC content resulted in decreased flexural strength and wettability of SPRG-filled RBC. SPRG-filled RBC released significantly higher amounts of multiple ions as contents of MPC increased. Meanwhile, SPRG-filled RBC with 5-wt% MPC significantly improved acid-neutralising properties than those of other test and control samples (P<0.001). SPRG-filled RBC with 3wt% MPC significantly reduced the amount of adsorbed bovine serum albumin and proteins from the brain heart infusion medium as compared to the control (P<0.01). A similar trend was observed in the attachment of four types of bacteria and multi-species biofilm (P<0.01). SIGNIFICANCE: Despite limitation in terms of deteriorations of some physical properties, addition of 3% MPC to SPRG-filled RBC leads to inhibition of the attachment of multi-species bacteria on its surface, as well as inhibition of biofilm growth. Moreover, the original important bioactive features of SPRG-filled RBC such as ion release and acid neutralisations are either maintained or improved upon adding MPC.


Assuntos
Biofilmes , Streptococcus mutans , Adsorção , Aderência Bacteriana , Resinas Compostas , Materiais Dentários , Humanos
9.
Sci Rep ; 9(1): 10959, 2019 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-31358850

RESUMO

Evaluation of facial asymmetry generally involves landmark-based analyses that cannot intuitively assess differences in three-dimensional (3D) stereoscopic structures between deviation and non-deviation sides. This study tested a newly developed similarity index that uses a mirroring technique to intuitively evaluate 3D mandibular asymmetry, and characterised the resulting lower facial soft tissue asymmetry. The similarity index was used to evaluate asymmetry before and after surgery in 46 adult patients (27 men, 19 women; age, 22 ± 4.8 years) with skeletal Class III malocclusion and facial asymmetry who underwent conventional bimaxillary orthognathic surgery. Relative to the midsagittal plane used as the reference plane, the non-overlapping volume of the mandible significantly decreased, and the similarity index significantly increased after surgery. Similarity indexes of the mandible and lower facial soft tissue were strongly negatively correlated with non-overlapping volumes of each measurement. Differences in bilateral hemi-mandibular and hemi-lower facial soft tissue surface and volume measurements before surgery were significantly negatively correlated with similarity indexes of the mandible before and after surgery. This newly developed similarity index and non-overlapping volume using a mirroring technique can easily and intuitively evaluate overall 3D morphological discrepancies, especially 3D mandibular asymmetry, before and after surgery in skeletal Class III patients with facial asymmetry.

10.
Sci Rep ; 9(1): 1432, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30723241

RESUMO

We evaluated the efficacy of light-curable fluoride varnish (LCFV) that contains 2-methacryloyloxyethyl phosphorylcholine (MPC) in terms of anti-biofouling properties and prevention of tooth enamel demineralization. MPC was mixed with and incorporated into LCFV at 0 (control), 1.5, 3.0, 5.0, 10.0, 20.0, and 40.0 weight percentage (wt%). Addition of high wt% of MPC resulted in increased film thickness and decreased the degree of conversion, indicating loss of the advantageous properties of LCFV. Addition of 1.5, 3, or 5 wt% MPC significantly reduced the amount of bovine serum albumin adsorbed from a solution and proteins adsorbed from brain heart infusion medium compared to the control (P < 0.001). A similar pattern was observed for bacterial adhesion: significantly less Streptococcus mutans cells adhered on the surface of LCFV with 1.5, 3, or 5 wt% MPC (P < 0.001) than on the control, and similar results were obtained for Actinomyces naeslundii and Streptococcus sanguinis adherence to LCFV with 3 wt% MPC. Finally, bacterial adhesion, surface microhardness loss, and the depth of demineralization were substantially lower on bovine tooth enamel surface coated with LCFV containing 3 wt% of MPC than in the control treatment (0 wt% MPC). Therefore, this novel LCFV containing a low concentration of MPC (e.g., 3 wt%) would be effective in anti-biofouling while maintaining the important advantageous features of light-curable fluoride in preventing demineralization.

11.
PLoS One ; 14(1): e0211007, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30653611

RESUMO

Calcium silicate-based cements (CSCs) are commonly used for endodontic procedures; however, their antibacterial effects are limited. The objective of this study was to develop a 2-methacryloyloxyethyl phosphorylcholine (MPC)-incorporated CSC with improved antibacterial properties, while maintaining the original advantageous features of CSC. MPC was incorporated into a commercial CSC (Endocem MTA) at 0 wt% (control), 1.5%, 3.0 wt%, 5.0 wt%, 7.5 wt%, and 10 wt%. The setting time, compressive strength, water sorption, and glycerol contact angle were measured. Protein absorption was measured and bacterial adhesion on the surface was evaluated using Enterococcus faecalis. The bactericidal effect was examined by the disc diffusion test. Mineralization ability was assessed based on calcium ion deposition, as assessed by alizarin red staining, after immersion into Hank's balanced salt solution for 7 days. High concentrations of MPC in CSC (7.5 wt% and 10 wt%) increased the setting time, reduced compressive strength, and reduced wettability. MPC (3 wt%) had greater protein repellent and anti-biofouling effects than those of control and test materials (P < 0.001). However, no bactericidal effect was observed for any control or test materials. There was greater calcium ion deposition on the surface of MPC-supplemented CSC than on the control (P < 0.001). The addition of 3 wt% MPC polymer to CSC confers protein-repellent properties and reduced bacterial attachment, with the potential for improved mineralization.


Assuntos
Compostos de Cálcio/química , Materiais Revestidos Biocompatíveis/química , Cimentos Dentários/química , Metacrilatos/química , Fosforilcolina/análogos & derivados , Silicatos/química , Enterococcus faecalis/crescimento & desenvolvimento , Fosforilcolina/química
12.
Oral Dis ; 25(2): 550-560, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30536847

RESUMO

OBJECTIVES: To investigate the effect of local injection of receptor activator of nuclear factor kappa B ligand (RANKL) on experimental tooth movement and subsequent alveolar bone remodelling in mice. MATERIALS AND METHODS: Sixty mice were randomised to receive daily local RANKL or phosphate-buffered saline injections in the buccal premaxillary bone for 14 of 21 days of incisor movement, followed by a 21-day retention period. Five mice from each group were euthanised on days 0, 3, 7, 14, 21 and 42, and specimens were prepared for haematoxylin and eosin, tartrate-resistant acid phosphatase and immunohistochemical staining. Five mice from each group were subjected to serial microcomputed tomography until day 42 for tooth movement and bone volume quantification. RESULTS: The experimental group showed significantly greater tooth movement and bone volume reduction on days 14 and 21; an increased osteoclast number on days 3, 7, 14 and 21; and no difference on day 42. Higher RANKL expression was observed on days 7 and 14, with remarkable alkaline phosphatase activity. No significant systemic changes were observed. CONCLUSION: Local RANKL injection leads to increased osteoclastic activity and facilitates tooth movement, followed by subsequent alveolar bone formation; this implies a reversible transitional acceleration of bone resorption.


Assuntos
Processo Alveolar/fisiologia , Remodelação Óssea/efeitos dos fármacos , Ligante RANK/farmacologia , Mobilidade Dentária/diagnóstico por imagem , Fosfatase Alcalina/metabolismo , Processo Alveolar/patologia , Animais , Contagem de Células , Injeções , Masculino , Maxila/patologia , Camundongos , Camundongos Endogâmicos ICR , Osteoblastos/metabolismo , Osteoclastos/patologia , Ligamento Periodontal/metabolismo , Ligante RANK/metabolismo , Distribuição Aleatória , Estresse Mecânico , Mobilidade Dentária/patologia , Microtomografia por Raio-X
13.
Cranio ; 37(4): 214-222, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29327661

RESUMO

OBJECTIVE: To assess changes in the tongue and hyoid bone positions and airway dimensions after maxillary protraction using lateral cephalograms. METHODS: Lateral cephalograms were obtained before (C0) and after (C1) an observation period for untreated children with skeletal Class I malocclusion and before (T0), immediately after (T1), and one year after (T2) maxillary protraction in children with skeletal Class III malocclusion. Cephalometric measurements were compared between the time points in both patient groups. RESULTS: Immediately after maxillary protraction, the tongue moved superiorly and the nasopharyngeal and superior oropharyngeal airway dimensions increased. No significant changes in the middle or inferior oropharyngeal airway dimensions or in the hyoid bone position were noted after treatment. CONCLUSIONS: Maxillary protraction improved tongue posture and modified the nasopharyngeal and superior oropharyngeal airway dimensions in patients with skeletal Class III malocclusion. Consequently, maxillary protraction may restore the intra- and extraoral balance and improve respiratory function.


Assuntos
Cefalometria/métodos , Osso Hioide/patologia , Má Oclusão de Angle Classe III/patologia , Má Oclusão de Angle Classe III/reabilitação , Má Oclusão de Angle Classe I/patologia , Má Oclusão de Angle Classe I/reabilitação , Maxila , Faringe/patologia , Língua/patologia , Tração/métodos , Criança , Aparelhos de Tração Extrabucal , Feminino , Humanos , Masculino , Má Oclusão de Angle Classe I/diagnóstico , Má Oclusão de Angle Classe III/diagnóstico , Fatores de Tempo , Tração/instrumentação
14.
Korean J Orthod ; 48(6): 384-394, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30450331

RESUMO

Objective: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. Methods: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200% of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. Results: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200% of the original length. Conclusions: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.

15.
PLoS One ; 13(9): e0202952, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30204811

RESUMO

Based on three-dimensional scanning and computer-aided design and computer-aided manufacturing (CAD/CAM) techniques, customized bracket systems are increasingly used. However, data remain limited regarding customized bracket design, characteristics, and stability. This study was undertaken to evaluate the design, bond strength, and residual adhesives of four different CAD/CAM customized brackets that were attached to human tooth specimens by indirect bonding. Thirty extracted human upper premolars were divided into five groups: Group 1, preadjusted self-ligating labial metal bracket; Group 2, lingual self-ligating metal injection molding customized bracket; Group 3, gold-casted lingual customized bracket; Group 4, labial self-ligating milled customized bracket; Group 5, labial customized resin base bracket. Except in Group 1, premolar specimens were scanned via model scanner, and the images were sent to each manufacturing company to fabricate customized brackets and transfer trays/jigs. Debonding force (DF; N) was measured by Instron universal testing machine and shear bond strength (SBS; MPa) was calculated via dividing DF by bonding area. Adhesive remnants were analyzed via stereo microscopic images. Group 2 (196.90±82.75 N) exhibited significantly higher DF than Group 1 (62.77±12.65 N); other groups exhibited similar DFs, compared with Group 1. No customized bracket groups exhibited significant differences in SBS, relative to Group 1 (6.73±1.36 MPa). However, SBS in Group 5 (11.46±7.22 MPa) was significantly higher than in Group 3 (3.58±2.14 MPa). Group 3 had significantly lower ARI scores than other groups (P<0.05). Customized brackets exhibited large deviations in DF and SBS; all customized bracket systems exhibited DF that was equivalent or superior to that of preadjusted brackets, even when placed by indirect bonding.


Assuntos
Desenho Assistido por Computador , Colagem Dentária , Braquetes Ortodônticos , Dente Pré-Molar , Análise do Estresse Dentário , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Cimentos de Resina , Resistência ao Cisalhamento
16.
Korean J Orthod ; 48(5): 283-291, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30206527

RESUMO

Objective: This study was conducted to perform histomorphometric evaluations of the bone surrounding orthodontic miniscrews according to their proximity to the adjacent tooth roots in the posterior mandible of beagle dogs. Methods: Four male beagle dogs were used for this study. Six orthodontic miniscrews were placed in the interradicular spaces in the posterior mandible of each dog (n = 24). The implanted miniscrews were classified into no loading, immediate loading, and delayed loading groups according to the loading time. At 6 weeks after screw placement, the animals were sacrificed, and tissue blocks including the miniscrews were harvested for histological examinations. After analysis of the histological sections, the miniscrews were categorized into three additional groups according to the root proximity: high root proximity, low root proximity, and safe distance groups. Differences in the bone-implant contact (BIC, %) among the root proximity groups and loading time groups were determined using statistical analyses. Results: No BIC was observed within the bundle bone invaded by the miniscrew threads. Narrowing of the periodontal ligament space was observed in cases where the miniscrew threads touched the bundle bone. BIC (%) was significantly lower in the high root proximity group than in the low root proximity and safe distance groups. However, BIC (%) showed no significant differences among the loading time groups. Conclusions: Regardless of the loading time, the stability of an orthodontic miniscrew is decreased if it is in contact with the bundle bone as well as the adjacent tooth root.

17.
Angle Orthod ; 88(5): 582-589, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29708396

RESUMO

OBJECTIVES: To identify unique characteristics of the craniofacial complex and dental maturity in girls with central precocious puberty (CPP). MATERIALS AND METHODS: This study included 34 Korean girls with idiopathic CPP (mean age, 8.6 ± .5 years) and 28 normal healthy girls of the same chronological age. An initial evaluation of the growth pattern of the craniofacial complex and dental maturity was conducted by analyzing lateral cephalometric and panoramic radiographs. RESULTS: The mandibular ramus height (44.4 ± 4.1 mm) and total mandibular length (10.8 ± 4.3 mm) ( P = .004 and .021, respectively) were greater and the lower anterior facial height was lesser (63.2 ± 2.4 mm) ( P = .040) in the CPP group than in the reference group. In addition, the gonial angle (12.9 ± 6.1°; P = .045) and the mandibular plane angle (34.9 ± 4.8°; P = .012) were smaller in girls with CPP than in normal healthy girls. All the mandibular teeth were more mature in girls with CPP ( P < .001). A strong positive correlation was observed between the mandibular tooth formation stages and the presence of CPP in girls ( r = .756 to .957; P < .001). CONCLUSIONS: CPP had an effect on the anteroposterior growth of the mandible in the craniofacial complex and the rotation of the mandibular plane angle. Early maturation of the mandibular teeth was observed in girls with CPP.


Assuntos
Ossos Faciais/patologia , Puberdade Precoce/patologia , Crânio/patologia , Dente/patologia , Estudos de Casos e Controles , Cefalometria , Criança , Ossos Faciais/diagnóstico por imagem , Feminino , Humanos , Mandíbula/diagnóstico por imagem , Mandíbula/patologia , Puberdade Precoce/diagnóstico por imagem , Radiografia Panorâmica , Crânio/diagnóstico por imagem , Dente/diagnóstico por imagem
18.
J Oral Maxillofac Surg ; 76(8): 1753-1762, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29549017

RESUMO

PURPOSE: The aim of the present study was to compare the long-term stability of bimaxillary surgery using an intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontic treatment. MATERIALS AND METHODS: The present retrospective study included 31 consecutive patients with skeletal Class III malocclusions who had undergone bimaxillary surgery (Le Fort I osteotomy and bilateral IVRO). Patients were divided into 2 groups based on treatment type: pre-orthodontic orthognathic surgery (POGS; n = 17) and conventional surgery with presurgical orthodontic treatment (CS; n = 14). Lateral cephalograms were obtained before surgery, 1 day after surgery, 1 month after surgery, 1 year after surgery, and 2 years after surgery to evaluate skeletal and soft tissue changes between the 2 groups. Data were analyzed using χ2 tests, Mann-Whitney U tests, repeated-measures analyses of variance, and independent t tests. RESULTS: There was no significant difference in skeletal or soft tissue measurements-with the exception of the angle between the sella-and-nasion plane and the occlusal plane (SN-OP; P < .001)-between the CS and POGS groups at 2 years after IVRO. The SN-OP had increased in the CS group but decreased in the POGS group at 2 years after surgery. CONCLUSIONS: These findings suggest that POGS and CS have similar long-term stability in patients with skeletal Class III malocclusion.


Assuntos
Má Oclusão de Angle Classe III/cirurgia , Osteotomia Maxilar/métodos , Procedimentos Cirúrgicos Ortognáticos/métodos , Adolescente , Cefalometria , Feminino , Humanos , Masculino , Ortodontia Corretiva , Osteotomia de Le Fort , Osteotomia Sagital do Ramo Mandibular/métodos , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
19.
Am J Orthod Dentofacial Orthop ; 153(1): 144-153, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29287640

RESUMO

INTRODUCTION: In this study, we assessed the precision and trueness of dental models printed with 3-dimensional (3D) printers via different printing techniques. METHODS: Digital reference models were printed 5 times using stereolithography apparatus (SLA), digital light processing (DLP), fused filament fabrication (FFF), and the PolyJet technique. The 3D printed models were scanned and evaluated for tooth, arch, and occlusion measurements. Precision and trueness were analyzed with root mean squares (RMS) for the differences in each measurement. Differences in measurement variables among the 3D printing techniques were analyzed by 1-way analysis of variance (α = 0.05). RESULTS: Except in trueness of occlusion measurements, there were significant differences in all measurements among the 4 techniques (P <0.001). For overall tooth measurements, the DLP (76 ± 14 µm) and PolyJet (68 ± 9 µm) techniques exhibited significantly different mean RMS values of precision than the SLA (88 ± 14 µm) and FFF (99 ± 14 µm) techniques (P <0.05). For overall arch measurements, the SLA (176 ± 73 µm) had significantly different RMS values than the DLP (74 ± 34 µm), FFF (89 ± 34 µm), and PolyJet (69 ± 18 µm) techniques (P <0.05). For overall occlusion measurements, the FFF (170 ± 55 µm) exhibited significantly different RMS values than the SLA (94 ± 33 µm), DLP (120 ± 28 µm), and PolyJet (96 ± 33 µm) techniques (P <0.05). There were significant differences in mean RMS values of trueness of overall tooth measurements among all 4 techniques: SLA (107 ± 11 µm), DLP (143 ± 8 µm), FFF (188 ± 14 µm), and PolyJet (78 ± 9 µm) (P <0.05). For overall arch measurements, the SLA (141 ± 35 µm) and PolyJet (86 ± 17 µm) techniques exhibited significantly different mean RMS values of trueness than DLP (469 ± 49 µm) and FFF (409 ± 36 µm) (P <0.05). CONCLUSIONS: The 3D printing techniques showed significant differences in precision of all measurements and in trueness of tooth and arch measurements. The PolyJet and DLP techniques were more precise than the FFF and SLA techniques, with the PolyJet technique having the highest accuracy.


Assuntos
Modelos Dentários/normas , Impressão Tridimensional
20.
Biomed Res Int ; 2018: 3936918, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30598994

RESUMO

Objective: The aim of this study was to evaluate the morphological characteristics of the palatal rugae in Korean subjects to determine whether the palatal rugae can be used as an appropriate reference area for three-dimensional digital model superimpositions. Materials and Methods: In total, 343 patients (110 men, 233 women; mean age, 25.6±8.2 years) who had a digital model taken at their initial visit were included, and the numbers and types of right and left palatal rugae were investigated according to the primary, secondary, and fragmentary rugae. Finally, the differences in the positions of the third primary ruga were investigated according to the presence of additional rugae posterior to the third primary ruga. Results: The number of primary palatal rugae ranged from one to six, with 43.5% of the subjects having three primary rugae and 36.1% having four primary rugae; there were no significant differences between sexes. Except for the fragment rugae, the numbers of primary and secondary rugae were not significantly different between the left and right sides. The third primary ruga was located more significantly anteriorly when there was an additional ruga posterior to the third primary ruga (P < 0.001). Conclusions: The numbers of the palatal rugae vary greatly among individuals, and this affects the anteroposterior position of the third primary ruga. When the third primary ruga is located anteriorly, care should be taken when using it as a reference area for superimposition with a digital model before and after orthodontic treatment.


Assuntos
Palato Duro/fisiologia , Adulto , Modelos Dentários , Feminino , Humanos , Masculino , Mucosa Bucal/fisiologia
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