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INTRODUCTION: This study aimed to evaluate the soft-tissue changes in the long-term after miniscrew-assisted rapid palatal expansion (MARPE) and conventional rapid palatal expansion (RPE) appliances compared with a matched control group using voxel-based superimposition of cone-beam computed tomography (CBCT) scans. METHODS: A total of 180 CBCTs for 60 patients at 3-time points were evaluated: pretreatment (T1), postexpansion (T2), and posttreatment (T3) for 3 groups: (1) MARPE, (2) RPE, and (3) controls (time-period T1 to T3: MARPE, 2 years 8 months; RPE, 2 years 9 months; control, 2 years 7 months). The voxel-based superimposition technique was used to superimpose the CBCT scans, after which the soft-tissue surfaces were extracted from the superimposed T1-CBCT, T2-CBCT, and T3-CBCT scans. Nine landmarks were identified on the CBCT scans: nasion, A-point, pogonion, right and left alar base, right and left zygoma, and right and left gonion. The coordinates of the 9 parameters were obtained in the x-axis, y-axis, and z-axis for the CBCT scans and subjected to statistical analyses. The changes in the soft-tissue surfaces were also evaluated by color-coded maps for short-term (T2) and long-term (T3) changes. The mean changes from T1 to T2 and T1 to T3 were tested against no change within the groups by paired t test, and the mean changes among the 3 groups were compared with analysis of variance F test with Tukey's Honest significant difference used for adjusting P values for multiple testing. RESULTS: In the short term, both MARPE and RPE led to a significant downward movement of pogonion, left gonion, and lateral movement of the right and left alar base compared with controls at T2 (P <0.05). In addition, MARPE led to a significant downward movement of right gonion than controls at T2 (P <0.05). Moreover, RPE led to a significant downward and forward movement of A-point and downward movement of the right and left alar base than controls at T2 (P <0.05). However, in the long-term, there were no significant differences in the soft-tissue changes among the MARPE, RPE, and control groups. CONCLUSIONS: MARPE and RPE do not lead to significant soft-tissue changes in the long term when compared with controls.
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Técnica de Expansão Palatina , Zigoma , Humanos , Tomografia Computadorizada de Feixe Cônico/métodos , MaxilaRESUMO
INTRODUCTION: The objective of this study was to evaluate the short-term and long-term hard-tissue changes with miniscrew-assisted rapid palatal expansion (MARPE) and rapid palatal expansion (RPE) compared with a matched control group with voxel-based superimposition using 3-dimensional cone-beam computed tomography (CBCT) scans. METHODS: A total of 180 CBCT scans were analyzed for 60 patients with a mean age of 13.9 years at 3 time points: pretreatment (T1), postexpansion (T2), and posttreatment (T3). Patients were divided into 3 groups: MARPE, RPE, and controls. Voxel-based superimposition was performed for CBCTs from T1 to T2 and T1 to T3 using the anterior cranial base as a reference. The hard-tissue surfaces were extracted after the superimposition procedure. Nine landmarks were analyzed: nasion, A-point, pogonion, left and right alar bases, zygoma, and gonion. Within-group changes were analyzed using linear mixed-effects models, including a random intercept per subject and the mixed effect of time (T1, T2, or T3) with test P values adjusted for multiple testing using Tukey's method. Between-group changes were analyzed using linear mixed-effects models, including a random intercept per subject and the mixed effects of time, group, and group × time interaction with P values adjusted for multiple testing using the Benjamin-Hochberg false discovery rate method. RESULTS: In the short term, both MARPE and RPE led to a significant downward movement of the right gonion and lateral movement of the right alar base compared with controls at T2 (P <0.05). In addition, MARPE led to a significant downward movement of pogonion and left gonion. RPE led to a significant downward movement of the A-point and lateral movement of the left alar base compared with controls at T2 (P <0.05). However, in the long-term, no changes were observed between the groups at T3. CONCLUSIONS: There were significant differences in pogonion, alar base, and gonion between MARPE, RPE, and control groups in the short term. However, all the hard-tissue changes were transient, as there were no differences between the 3 groups in the long term.
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INTRODUCTION: The objective of this study was to analyze the short-term and long-term effects of miniscrew-assisted rapid palatal expansion (MARPE) and conventional rapid palatal expansion (RPE) appliances on cranial and circummaxillary sutures as compared with a matched control group. METHODS: One hundred and eighty cone-beam computed tomography scans for 60 subjects were evaluated for the 3 groups: (1) MARPE (n = 20; aged 13.7 ± 1.74 years), (2) RPE (n = 21; age 13.9 ± 1.14 years), and (3) control (n = 19; age 13.3 ± 1.49 years) at pretreatment (T1), postexpansion (T2), and posttreatment (T3) (T1 to T3: MARPE, 2 years 8 months; RPE, 2 years 9 months; control, 2 years 7 months). Frontonasal suture, frontomaxillary suture, zygomaticomaxillary suture, zygomaticofrontal suture, intermaxillary suture, pterygomaxillary suture, nasomaxillary suture, and zygomaticotemporal suture were measured on the right and left sides for all 3 time labels. In addition, midpalatal suture was measured at the incisor, canine, and molar levels. RESULTS: Within-group analysis showed that MARPE and RPE led to a significant increase in the widths of frontonasal, frontomaxillary, intermaxillary, nasomaxillary, and midpalatal suture at incisor, canine, and molar levels at T2 compared with T1. Between-group analysis showed that MARPE and RPE significantly increased the width of the intermaxillary and midpalatal suture at the incisor, canine, and molar compared with controls at T2. In the long term, between-group comparisons showed no significant difference among the 3 groups except that MARPE led to a significant increase in the width of midpalatal suture at incisor, canine, and molar levels compared with RPE and controls at T3. CONCLUSIONS: MARPE led to a significant increase in the width of the midpalatal suture at incisor, canine, and molar levels compared with RPE and controls in the long term. There was no difference in the width of other cranial and circummaxillary sutures among the 3 groups in the long term.
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Maxila , Técnica de Expansão Palatina , Maxila/diagnóstico por imagem , Palato/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Suturas Cranianas/diagnóstico por imagem , SuturasRESUMO
INTRODUCTION: The purpose of this study was to evaluate the long-term effects of bone-anchored and tooth-anchored expansion appliances on alveolar bone in vertical and horizontal dimensions, compared with controls, using cone-beam computed tomography. METHODS: We evaluated 180 cone-beam computed tomography scans for 60 patients at 3-time points: T1 (pretreatment), T2 (postexpansion), and T3 (posttreatment), for 3 groups: bone-anchored expansion appliance (BA), tooth-anchored expansion appliance (TA), and controls (T1-T3: BA, 2 years 8 months; TA, 2 years 9 months; control: 2 years 7 months). The intermolar width, molar angulation, palatal width, vertical buccal bone height, buccal bone thickness at the alveolar crest, and root apex were measured in the 3 groups at different time points. RESULTS: In the short term, both BA and TA led to a statistically significant increase in the intermolar width and vertical buccal bone loss after expansion compared with controls. Vertical buccal bone loss was significantly greater in TA than in BA. In addition, TA led to significantly increased molar angulation (buccal tipping) compared with controls at T2. There were no significant differences in the 3 groups in the long term except vertical buccal bone loss, which was significantly greater in TA than controls. A substantial correlation was found between molar angulation and vertical buccal bone loss, and a moderate negative correlation was found between intermolar width and buccal bone thickness at the alveolar crest at T3. CONCLUSIONS: There was no difference in the treatment outcomes between the 3 groups in the long term except vertical buccal bone loss, which was significantly increased in the TA group compared with controls.
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Maxila , Técnica de Expansão Palatina , Processo Alveolar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Humanos , PalatoRESUMO
INTRODUCTION: The purpose of this study was to use cone-beam computed tomography to compare immediate and long-term effects of conventional and miniscrew-assisted rapid palatal expansion (MARPE) appliances on root resorption in 2 treatment groups and a control group. METHODS: One hundred eighty cone-beam computed tomography images of 60 patients at 3 time points were assessed: initial, postexpansion, and debond. The patients were divided into 3 groups: control (n = 19), rapid palatal expansion (RPE) appliance (n = 21), and MARPE (n = 20). The period of initial to debond varied for the 3 groups: 2 years, 7 months for controls; 2 years, 9 months for RPE; and 2 years, 8 months for MARPE. The length of mesiobuccal, distobuccal, and palatal root of the maxillary first molar (1M); the buccal root of maxillary first premolar; and second premolar were measured. The inclination of the 1M, intercuspal width (ICW), interroot width (IRW), ICW/IRW ratio, maxillary skeletal width were measured in all 3 groups at different time points. RESULTS: Immediately after expansion, RPE and MARPE groups showed a significant increase in the molar inclination, ICW, ICW/IRW ratio, and maxillary skeletal width compared with controls at postexpansion. However, the long-term comparison did not show any significant difference for root resorption and expansion parameters between the 3 groups, except the ICW/IRW ratio, which was higher in MARPE than controls at debond. A significant negative association was observed between the length of the mesiobuccal root of 1M and molar inclination (ß = -0.025; 95% confidence interval, -0.050 to 0.0008; P <0.05). The expansion of ICW and IRW did not show a significant association with root resorption. CONCLUSIONS: The long-term outcomes showed no difference in the amount of root resorption between the RPE, MARPE, and control groups. Molar inclination showed a significant negative association with the length of the mesiobuccal root of the 1M.
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Técnica de Expansão Palatina , Reabsorção da Raiz , Tomografia Computadorizada de Feixe Cônico/métodos , Humanos , Maxila/diagnóstico por imagem , Palato/diagnóstico por imagem , Reabsorção da Raiz/diagnóstico por imagem , Reabsorção da Raiz/etiologiaRESUMO
INTRODUCTION: The objective of this research was to compare the oropharyngeal volume and minimal cross-sectional area (MCA) changes after maxillary expansion using either the Damon system or Hyrax appliances as assessed through cone-beam computed tomography (CBCT) imaging. METHODS: Patients aged between 11 and 17 years with skeletal maxillary transverse discrepancy in need of maxillary expansion were included and allocated randomly into 1 of the 2 treatment groups, Damon or Hyrax. Patients underwent CBCT imaging at 2 time points: T1, after initial clinical evaluation before treatment, and T2, after completion of full orthodontic treatment. The CBCT data were assessed using Dolphin software (Dolphin Imaging & Management Solutions, Chatsworth, Calif). In addition, a qualitative assessment of breathing function was done using the modified Nasal Obstruction and Septoplasty Effectiveness Scale questionnaire. RESULTS: A statistically significant increase in the oropharyngeal volume (2.23 mL; P = 0.005) and MCA (29.72 mm2; P = 0.007) after the completion of treatment (T2 - T1) for the Hyrax group was suggested. No statistically significant difference was found in the Damon group for volume (1 mL; P = 0.311) and for MCA (7.32 mm2; P = 0.643). In addition, no statistically significant difference was found in the breathing function in both treatment groups (P >0.05). CONCLUSIONS: Hyrax expansion followed by fixed appliances produced more dimensional upper airway changes at the oropharyngeal level than the Damon system approach. No breathing functional changes were noted in either samples.
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Maxila , Técnica de Expansão Palatina , Adolescente , Criança , Tomografia Computadorizada de Feixe Cônico , Humanos , Nariz , Orofaringe/diagnóstico por imagemRESUMO
OBJECTIVES: To evaluate the long-term effects of mini-screw-assisted rapid palatal expansion (MARPE), rapid palatal expansion (RPE), and controls on the nasal cavity with cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 180 CBCT scans that were part of a previous randomized trial were evaluated retrospectively for 60 patients at pretreatment (T1), postexpansion (T2), and posttreatment (T3). Patients were randomly assigned into 3 groups: MARPE, RPE, and controls (time period T1 to T3; MARPE: 2 years 8 months; RPE: 2 years 9 months; control: 2 years 7 months). Nasal height, nasal length, nasion-ANS height, ANS-PNS length, pyriform height, and nasal septal deviation angle were measured. The changes in alar width, alar base width, anterior nasal cavity width, posterior nasal cavity width, maxillary intermolar width, and maxillary intercanine width were also evaluated. RESULTS: The alar base width, posterior nasal cavity width, anterior nasal cavity width, maxillary intercanine width, and maxillary intermolar width significantly increased (P < .05), and the nasal septal deviation angle significantly decreased (P < .05) in both the MARPE and RPE groups as compared with controls in the short term. In the long term, the nasal septal deviation angle was significantly decreased (P < .05) in the MARPE and RPE groups as compared with controls, and the posterior nasal cavity width was significantly increased (P < .05) in the MARPE group compared with the RPE group and controls. CONCLUSIONS: MARPE and RPE led to a significant increase in the nasal cavity and alar base width compared with controls in the short term. In the long term, a significant increase was observed only in the posterior nasal cavity width with MARPE. Both MARPE and RPE led to a minimal decrease in nasal septal deviation angle in comparison with controls.
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Cárie Dentária , Técnica de Expansão Palatina , Parafusos Ósseos , Tomografia Computadorizada de Feixe Cônico/métodos , Humanos , Maxila , Cavidade Nasal/diagnóstico por imagem , Palato , Estudos RetrospectivosRESUMO
BACKGROUND: The objective of this study was to evaluate the short-term and long-term effects of tooth-anchored and bone-anchored maxillary expansion appliances on the condyle-fossa relationship, compared to those in a matched control group. Another objective of the study was to evaluate whether the amount of dental and skeletal expansion is correlated with the condyle-fossa relationship. METHODS: A total of 180 cone-beam computed tomography scans (CBCTs) for 60 subjects were analyzed for 3 groups: 1) bone-anchored maxillary expansion (BA; n = 20); 2) tooth-anchored maxillary expansion (TA; n = 21); and 3) controls (n = 19) at pretreatment, post-expansion (T2), and post-treatment (T3). The posterior joint space (PJS), superior joint space (SJS), anterior joint space, angle of mandibular condyle, distance of the condyle to the mid-sagittal plane, the inter-molar cuspal width, and the skeletal maxillary width (SMW) were measured for all 3 groups. RESULTS: Both BA and TA led to a significant increase in inter-molar cuspal width, SMW, and TA led to a significant increase in PJS as compared to controls at T2. However, there was no significant difference in the joint spaces between the BA, TA, and control groups in the long term. Both the BA and TA groups showed a significant increase in SMW at T3 compared to the control group. Molar extrusion showed a weak correlation with PJS at T2 (r = 0.46) and T3 (r = 0.51), and a moderate correlation with SJS at T2 (r = 0.61) and T3 (r = 0.69). CONCLUSIONS: TA led to a significant increase in PJS, compared to a control group, at T2, but there was no long-term difference in the condyle-fossa relationship among the BA, TA, and control groups. Molar extrusion showed moderate correlation with SJS and PJS.
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Maxila , Técnica de Expansão Palatina , Cefalometria , Tomografia Computadorizada de Feixe Cônico , Humanos , Côndilo Mandibular/diagnóstico por imagemRESUMO
OBJECTIVES: To evaluate the long-term effects on airway in patients with mini-screw-assisted rapid palatal expansion (MARPE), rapid palatal expansion (RPE), and controls with three-dimensional cone-beam computed tomography (CBCT) analysis. MATERIALS AND METHODS: A total of 180 CBCTs of 60 patients were analyzed at different time points, such as pretreatment, postexpansion, and posttreatment. Patients were divided into three groups: mini-screw assisted rapid palatal expansion (MARPE), rapid palatal expansion (RPE), and controls. The nasal cavity, nasopharyngeal, oropharyngeal, and laryngopharyngeal airway volume and area were measured. Changes in total airway volume, total airway area, minimal cross-sectional area, maxillary intermolar width, external maxillary width, and palatal width were also evaluated. RESULTS: Both MARPE and RPE caused a statistically significant increase in the airway after expansion as compared with the control group, but there was no statistically significant difference in the change in airway between MARPE, RPE, and the control group at posttreatment, except for nasopharyngeal volume, which was significantly increased in the MARPE group. There was no correlation between the amount of expansion and increase in total airway volume. CONCLUSIONS: There was a significant increase in total airway volume, total airway area, and minimal cross-sectional area with MARPE and RPE immediately after expansion, but at posttreatment, the changes in the MARPE and RPE groups were similar to the change in the control group. However, MARPE led to a significant long-term increase in nasopharyngeal volume. The amount of expansion did not correlate with the increase in pharyngeal airway volume.
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Técnica de Expansão Palatina , Palato , Parafusos Ósseos , Tomografia Computadorizada de Feixe Cônico , Humanos , Maxila , Palato/diagnóstico por imagemRESUMO
Obstructive sleep apnea (OSA) is a sleeping breathing disorder. In children, adenotonsillar hypertrophy remains the main anatomical risk factor of OSA. The aim of this study was to assess the current scientific data and to systematically summarize the evidence for the efficiency of adenotonsillectomy (AT) and orthodontic treatment (i.e., rapid maxillary expansion (RME) and mandibular advancement (MA)) in the treatment of pediatric OSA. A literature search was conducted in several databases, including PubMed, Embase, Medline, Cochrane and LILACS up to 5th April 2020. The initial search yielded 509 articles, with 10 articles being identified as eligible after screening. AT and orthodontic treatment were more effective together than separately to cure OSA in pediatric patients. There was a greater decrease in apnea hypoapnea index (AHI) and respiratory disturbance index (RDI), and a major increase in the lowest oxygen saturation and the oxygen desaturation index (ODI) after undergoing both treatments. Nevertheless, the reappearance of OSA could occur several years after reporting adequate treatment. In order to avoid recurrence, myofunctional therapy (MT) could be recommended as a follow-up. However, further studies with good clinical evidence are required to confirm this finding.
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INTRODUCTION: The aim of this multi-center retrospective study was to quantify the changes in alveolar bone height and thickness after using two different rapid palatal expansion (RPE) activation protocols, and to determine whether a more rapid rate of expansion is likely to cause more adverse effects, such as alveolar tipping, dental tipping, fenestration and dehiscence of anchorage teeth. METHODS: The sample consisted of pre- and post-expansion records from 40 subjects (age 8-15 years) who underwent RPE using a 4-banded Hyrax appliance as part of their orthodontic treatment to correct posterior buccal crossbites. Subjects were divided into two groups according to their RPE activation rates (0.5 mm/day and 0.8 mm/day; n = 20 each group). Three-dimensional images for all included subjects were evaluated using Dolphin Imaging Software 11.7 Premium. Maxillary base width, buccal and palatal cortical bone thickness, alveolar bone height, and root angulation and length were measured. Significance of the changes in the measurements was evaluated using Wilcoxon signed-rank test and comparisons between groups were done using ANOVA. Significance was defined at p ≤ 0.05. RESULTS: RPE activation rates of 0.5 mm per day (Group 1) and 0.8 mm per day (Group 2) caused significant increase in arch width following treatment; however, Group 2 showed greater increases compared to Group 1 (p < 0.01). Buccal alveolar height and width decreased significantly in both groups. Both treatment protocols resulted in significant increases in buccal-lingual angulation of teeth; however, Group 2 showed greater increases compared to Group 1 (p < 0.01). CONCLUSION: Both activation rates are associated with significant increase in intra-arch widths. However, 0.8 mm/day resulted in greater increases. The 0.8 mm/day activation rate also resulted in more increased dental tipping and decreased buccal alveolar bone thickness over 0.5 mm/day.
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Processo Alveolar/anatomia & histologia , Arco Dental/anatomia & histologia , Técnica de Expansão Palatina , Adolescente , Processo Alveolar/diagnóstico por imagem , Criança , Tomografia Computadorizada de Feixe Cônico , Arco Dental/diagnóstico por imagem , Humanos , Imageamento Tridimensional , Má Oclusão/terapia , Maxila/anatomia & histologia , Maxila/diagnóstico por imagem , Estudos RetrospectivosRESUMO
OBJECTIVE: To evaluate the accuracy and reliability of the diagnostic tools available for assessing maxillary transverse deficiencies. METHODS: An electronic search of three databases was performed from their date of establishment to April 2015, with manual searching of reference lists of relevant articles. Articles were considered for inclusion if they reported the accuracy or reliability of a diagnostic method or evaluation technique for maxillary transverse dimensions in mixed or permanent dentitions. Risk of bias was assessed in the included articles, using the Quality Assessment of Diagnostic Accuracy Studies tool-2. RESULTS: Nine articles were selected. The studies were heterogeneous, with moderate to low methodological quality, and all had a high risk of bias. Four suggested that the use of arch width prediction indices with dental cast measurements is unreliable for use in diagnosis. Frontal cephalograms derived from cone-beam computed tomography (CBCT) images were reportedly more reliable for assessing intermaxillary transverse discrepancies than posteroanterior cephalograms. Two studies proposed new three-dimensional transverse analyses with CBCT images that were reportedly reliable, but have not been validated for clinical sensitivity or specificity. No studies reported sensitivity, specificity, positive or negative predictive values or likelihood ratios, or ROC curves of the methods for the diagnosis of transverse deficiencies. CONCLUSIONS: Current evidence does not enable solid conclusions to be drawn, owing to a lack of reliable high quality diagnostic studies evaluating maxillary transverse deficiencies. CBCT images are reportedly more reliable for diagnosis, but further validation is required to confirm CBCT's accuracy and diagnostic superiority.
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Introduction: Patients presenting Temporomandibular Disorders (TMD) are common in our daily clinical practice. One of the possible conditions that lead to TMD is the habitual chewing side syndrome. Methods: In this case report a clinical approach is presented to manage the TMD related to unilateral vicious mastication. A 42 years old woman presented reporting headaches, difficulty to open mouth, presence of sensitivity in the left ear and TMJ region, soreness on the left side temporal region and sensitivity in the anterior inferior teeth. It was noted that the patient habitually clenched and ground teeth. Patient mentioned chew more on the left side. Results: After confirming the unilateral mastication, a modified therapy based on the Neuro occlusal Rehabilitation was applied through the use of a splint. After 60 days the patient described absence of the previous symptoms and pain relief. Conclusion: The evaluation of the masticatory pattern is often neglected; however, it is of great importance since it can lead to several conditions such as condyle wear, pain, alteration of the occlusal plane, deviation of the medial line, deviation of the mandible at mouth opening, bone alterations, Temporomandibular joint(TMJ) hypofunction, headache, among others.
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ABSTRACT Introduction: The aim of this multi-center retrospective study was to quantify the changes in alveolar bone height and thickness after using two different rapid palatal expansion (RPE) activation protocols, and to determine whether a more rapid rate of expansion is likely to cause more adverse effects, such as alveolar tipping, dental tipping, fenestration and dehiscence of anchorage teeth. Methods: The sample consisted of pre- and post-expansion records from 40 subjects (age 8-15 years) who underwent RPE using a 4-banded Hyrax appliance as part of their orthodontic treatment to correct posterior buccal crossbites. Subjects were divided into two groups according to their RPE activation rates (0.5 mm/day and 0.8 mm/day; n = 20 each group). Three-dimensional images for all included subjects were evaluated using Dolphin Imaging Software 11.7 Premium. Maxillary base width, buccal and palatal cortical bone thickness, alveolar bone height, and root angulation and length were measured. Significance of the changes in the measurements was evaluated using Wilcoxon signed-rank test and comparisons between groups were done using ANOVA. Significance was defined at p ≤ 0.05. Results: RPE activation rates of 0.5 mm per day (Group 1) and 0.8 mm per day (Group 2) caused significant increase in arch width following treatment; however, Group 2 showed greater increases compared to Group 1 (p < 0.01). Buccal alveolar height and width decreased significantly in both groups. Both treatment protocols resulted in significant increases in buccal-lingual angulation of teeth; however, Group 2 showed greater increases compared to Group 1 (p < 0.01). Conclusion: Both activation rates are associated with significant increase in intra-arch widths. However, 0.8 mm/day resulted in greater increases. The 0.8 mm/day activation rate also resulted in more increased dental tipping and decreased buccal alveolar bone thickness over 0.5 mm/day.
RESUMO Introdução: o objetivo do presente estudo retrospectivo multicêntrico foi quantificar as alterações na altura e na espessura do osso alveolar após o uso de dois diferentes protocolos de ativação na expansão rápida da maxila (ERM), bem como determinar se uma taxa de expansão mais rápida tem maior probabilidade de causar mais efeitos adversos, tais como inclinação dos dentes e do processo alveolar, fenestração e deiscência dos dentes de ancoragem. Métodos: a amostra consistiu de registros pré- e pós-expansão de 40 indivíduos (com idades entre 8 e 15 anos) que se submeteram à expansão rápida da maxila usando o aparelho Hyrax com quatro bandas como parte de seu tratamento ortodôntico para correção da mordida cruzada posterior. Os indivíduos foram divididos em dois grupos, de acordo com a taxa de ativação na expansão rápida da maxila (0,5 mm/dia e 0,8 mm/dia; n = 20 cada grupo). Imagens tridimensionais de todos os indivíduos da amostra foram avaliadas com o uso do software Dolphin Imaging v. 11.7 Premium. Foram analisadas as seguintes medidas: largura da base da maxila, espessura das corticais ósseas vestibular e lingual, altura do osso alveolar, angulação e comprimento das raízes. A significância das alterações nessas medidas foi avaliada com o teste não paramétrico de Wilcoxon e as comparações entre os grupos foram feitas usando a ANOVA. A significância foi definida como p ≤ 0,05. Resultados: as taxas de ativação na ERM de 0,5mm/dia (Grupo 1) e 0,8mm/dia (Grupo 2) causaram aumento significativo na largura da arcada após o tratamento. Porém, o Grupo 2 apresentou maior aumento, se comparado ao Grupo 1 (p < 0,01). A altura e a largura do osso alveolar vestibular diminuíram significativamente em ambos os grupos. Ambos os protocolos de tratamento resultaram em aumento significativo na inclinação vestibulolingual dos dentes. Porém, o Grupo 2 apresentou maior aumento, em comparação ao Grupo 1 (p < 0,01). Conclusão: ambas as taxas de ativação estão associadas a um aumento significativo nas larguras intra-arcada; entretanto, a taxa de 0,8mm/dia resultou em maior aumento. Essa mesma taxa de ativação também resultou em maior inclinação dos dentes e em redução mais acentuada da espessura do osso alveolar vestibular.