Effect of miniscrew placement height on the distribution of biological forces produced by clear aligner for mandibular molar distalization / 口腔疾病防治

Objective@#To explore the effect of different miniscrew placement heights on the distribution of biological forces produced by clear aligner combined with intramaxillary traction for mandibular molar distalization, to identify the miniscrew location that is conducive to the protection of lower anterior tooth anchorage and to provide a reference that can be used when designing clinical treatments.@*Methods@#Mimics, GeomagicStudio 2017, SolidWorks 2016, and Ansys workbench were used to establish finite element analysis models and perform mechanical analysis under the following six working conditions: working condition 1 was the control group without miniscrews; working conditions 2 to 5 had miniscrew in the buccal bone cortex between the first and second molars of the lower jaw 10 mm, 7 mm, 4 mm, and 1 mm from the top of the alveolar crest, respectively; working condition 6 had the miniscrew in the center of the buccal tongue at the anterior edge of the ascending branch of the lower jaw 5 mm above the occlusal plane.@*Results@#On the sagittal axis, miniscrew anchorage caused distal displacement of all teeth. Compared to the control group, in the miniscrew group, the displacement of the anterior molars exceeded that of the second molars. On the vertical axis, the result in the control group was similar to backward bending; the results in the miniscrew groups resembled the effect of a lever, lowering the lateral incisors and canines and raising the central incisors and first premolars. On the coronal axis, the second premolars and the first molars showed lingual displacement in the control group, and only the premolars and first molars showed lingual displacementin the miniscrew groups. The canines were the teeth that were most strongly affected by the change in miniscrew placement height.@*Conclusion@#The higher the miniscrew position is, the stronger the protective effect on the anterior anchorage. According to the miniscrew placement height, the mandibular arch should be properly narrowed, the central incisors and first premolars should be lowered, and the lateral incisors and canines should be raised when designing clinical treatments.

Contribution of Digital Technology to the Surgical Technique of Miniscrew Insertion: a Literature Review

Orthodontic miniscrews are used to achieve absolute anchorage. Their insertion technique is simple but must be precise to avoid intra- and postoperative complications. This study aimed to review the literature on the role of digital technology in the precise placement of miniscrews and to describe the different stages of the insertion guide manufacturing chain. The databases used were PubMed, Science Direct, and Google Scholar, including the following English descriptors: "Orthodontic Anchorage Procedures," "Cone Beam Computed Tomography." Digital technology improves the accuracy of miniscrew placement by using 3D imaging to assess the quantity and quality of bone and the proximity of anatomical structures in the area to be implanted. By combining 3D imaging with the new techniques of 3D printing and virtual planning, the orthodontist can obtain a personalized placement guide for the patient using computer-aided design and manufacturing techniques. A digitally-assisted miniscrew insertion system is a promising technique for precise and safe miniscrew insertion but cannot be used routinely. Therefore, large-scale studies are needed to map miniscrew insertion in different areas, considering ethnicity, gender, and different anatomical characteristics.

Harmonização do sorriso: aliando ortodontia e estética / Smile harmonization: combining orthodontics and aesthetics

Atualmente é evidente a demanda contínua por padrões de beleza, cada vez mais impecáveis, um sorriso alinhado e harmônico com dentes brancos para se sorrir com confiança. O tratamento odontológico interdisciplinar tem como intuito proporcionar uma boa saúde periodontal, restabelecer a estética e a função do sistema estomatognático. Objetivo: apresentar um relato de caso clínico envolvendo harmonização do sorriso como cirurgia plástica periodontal para alinhamento da margem gengival na região anterior e restaurações diretas em resina composta após a finalização do tratamento ortodôntico, evidenciando a importância da abordagem conservadora e multidisciplinar no âmbito do tratamento estético. Relato de caso: Realizamos o tratamento ortodôntico com aparelho autoligado cerâmico para alinhamento do arco dental e intrusão do elemento 13, em sequência executamos um recorte gengival nos elementos 12 e 22, clareamento dental associado após 15 dias, subsequentemente, reanatomização dentária no elemento 44 para que o elemento 13 não voltasse a extruir pela falta de contato oclusal, e por fim, remodelação dental fazendo uso de resina composta nos elementos 12, 21 e 22 devido a manchas de hipocalcificação dental. Conclusão: Contudo, a estética bucal tem a capacidade de possibilitar a melhoria na autoestima, devolvendo à função, proporcionando satisfação e bem-estar ao indivíduo, enaltecendo o sorriso.

Currently, the continuous demand for increasingly impeccable beauty standards is evident, an aligned and harmonic smile with white teeth to smile with confidence. Interdisciplinary dental treatment aims to provide good periodontal health, restore the aesthetics and function of the stomatognathic system. Objective: to present a clinical case report involving smile harmonization as periodontal plastic surgery for aligning the gingival margin in the anterior region and direct composite resin restorations after completion of orthodontic treatment, highlighting the importance of a conservative and multidisciplinary approach in the field of aesthetic treatment . Case report: We performed orthodontic treatment with a self-ligating ceramic appliance for aligning the dental arch and intruding element 13, then performed a gingival cutout on elements 12 and 22, associated tooth whitening after 15 days, subsequently, dental reanatomization on element 44 to that element 13 would not extrude again due to the lack of occlusal contact, and finally, dental remodeling using composite resin in elements 12, 21 and 22 due to dental hypocalcification stains. Conclusion: However, oral aesthetics has the ability to improve self-esteem, returning to function, providing satisfaction and well-being to the individual, enhancing the smile.

Histological Evaluation of the Effect of Alendronate on the Maxillary Bone of Wistar Rats Combined with Orthodontic Movement of Intense Force / Evaluación Histológica del Efecto del Alendronate en el Hueso Maxilar de Ratas Wistar Combinado con Movimiento de Ortodoncia de Fuerzas Intensas

SUMMARY: To evaluate the histological adverse effects of alendronate administered systemically and topically in combination with orthodontic movement by intense force. Thirty-six 24-week-old female Wistar rats, ovariectomized, were used and divided into three groups (n = 12/group): control, locally treated with saline (0.07 ml/kg/week) (group 1) and experimental, treated with alendronic acid systemically (0.07 mg/kg/week) (group 2) and locally (7 mg/kg/week) (group 3). At 14 days, an orthodontic anchor was installed in the right first molar, and a force of 144 cN was applied for 28 days. The samples were processed for histological evaluation. Descriptive statistics, Shapiro-Wilk tests, one-way ANOVA with Bonferroni correction, one-way repeated measures ANOVA and chi-square tests were performed. All tests were statistically significant at p <0.05. The adverse events found in all groups were inflammation and osteoclastic activity. In the bisphosphonate-treated groups, there were statistically significant differences (p = 0.005) in the osteoclastic activity between the two hemiarcates. All rats in group 2 presented paralytic ileus. Compared to local administration, systemic treatment with alendronic acid produces more adverse effects, such as inflammation, fibrinoid necrosis, and osteoclastic activity. During the application of intense forces, it was not possible to show that there is necrosis associated with bisphosphonates.

Evaluar los efectos adversos histológicos del alendronato administrado sistémica y tópicamente en combinación con movimientos ortodóncicos de fuerza intensa. Treinta y seis ratas Wistar hembras de 24 semanas de edad, ovariectomizadas, fueron utilizadas y divididas en tres grupos (n = 12/grupo): control, tratado localmente con solución salina (0,07 ml/kg/semana) (grupo 1) y experimental, tratados con ácido alendrónico por vía sistémica (0,07 mg/kg/semana) (grupo 2) y local (7 mg/kg/semana) (grupo 3). A los 14 días se instaló un anclaje de ortodoncia en el primer molar derecho y se aplicó una fuerza de 144 cN durante 28 días. Las muestras fueron procesadas para evaluación histológica. Se realizó estadística descriptiva, pruebas de Shapiro-Wilk, ANOVA de una vía con corrección de Bonferroni, ANOVA de medidas repetidas de una vía y pruebas de chi-cuadrado. Todas las pruebas fueron estadísticamente significativas con un p <0,05. Los eventos adversos encontrados en todos los grupos fueron inflamación y actividad osteoclástica. En los grupos tratados con bisfosfonatos hubo diferencias estadísticamente significativas (p = 0,005) en la actividad osteoclástica entre los dos hemiarcados. Todas las ratas del grupo 2 presentaron íleo paralítico. En comparación con la administración local, el tratamiento sistémico con ácido alendrónico produce más efectos adversos, como inflamación, necrosis fibrinoide y actividad osteoclástica. Durante la aplicación de fuerzas intensas, no fue posible demostrar que existe necrosis asociada con los bisfosfonatos.

Tomographic evaluation of mandibular buccal shelf in patients with different vertical growth pattern / Evaluación de la placa ósea mandibular en pacientes con diferente patrón de crecimiento vertical

The purpose of this research was the tomographic evaluation of the Mandibular Buccal Shelf (MBS) in orthodontic patients with different vertical growth pattern. An observational, descriptive, cross-sectional and retrospective study was conducted. Tomographic images of patients aged 14 to 40 years were observed and a database was formed with those that met the inclusion criteria. The sample size was 10 for each group according to vertical growth pattern (hypodivergent, normodivergent and hyperdivergent). Then four zones of frequent insertion of extralveolar mini-screws were selected in the MBS, taking as a reference the mesial and distal roots of the first and second mandibular molar. When comparing the characteristics of MBS between vertical growth patterns, between sexes and hemiarchs, no statistically significant differences were found. However, when the characteristics of MBS were compared according to the reference root, it was found that there were statistically significant differences. The vestibular area to the distal root of the second mandibular molar presented the highest values in terms of angulation, height and thickness. There are no significant differences in the bone characteristics of MBS according to vertical growth patterns, sexes or hemiarchs. Angulation, height and thickness progressively increase from the vestibular bone of the mesial root of the first mandibular molar to the distal root of the second molar.

El propósito de esta investigación fue la evaluación tomográfica de la placa ósea mandibular (POM) en pacientes de ortodoncia con diferente patrón de crecimiento vertical. Se realizó un estudio de tipo observacional, descriptivo, transversal y retrospectivo. Se observó imágenes tomográficas de pacientes de 14 a 40 años de edad y se formó una base de datos con las que cumplían los criterios de selección. El tamaño de muestra fue de 10 para cada grupo según patrón de crecimiento vertical (hipodivergentes, normodivergentes e hiperdivergentes). Luego se seleccionaron cuatro zonas de inserción frecuente de minitornillos extralveolares en la POM, tomando como referencia las raíces mesial y distal del primer y segundo molar mandibular. Al realizar la comparación de las características de la POM entre patrones de crecimiento vertical, entre sexos y hemiarcadas no se encontraron diferencias estadísticamente significativas. Sin embargo, cuando se comparó las características de la POM según la raíz de referencia se encontró que había diferencias estadísticamente significativas. La zona vestibular a la raíz distal de la segunda molar mandibular presento los mayores valores en cuanto angulación, altura y grosor. No existen diferencias significativas en las características óseas de la POM según patrones de crecimiento vertical, sexos o hemiarcadas. La angulación, la altura y el grosor aumenta progresivamente desde el hueso vestibular de la raíz mesial del primer molar mandibular hacia la raíz distal del segundo molar.

Calcitonin as a Pharmacological Anchorage in Orthodontics

Objective: This study aimed to evaluate the effects of salmon calcitonin administration as a pharmacological anchoring agent in orthodontics and to determine the influence of locally applied calcitonin on serum calcium levels. The secondary aim was to observe the response of dental and periodontal tissues using light microscopy. Methods: Fourteen healthy male adult Wistar rats with an average weight of 250 g had their teeth moved, seven of which received a local injection of salmon calcitonin in the furcation region of the left upper first molar. Concurrently, the remaining seven were used as controls. In the control group, saline solution was injected in the bifurcation region of tooth 26 to subject these animals to the same stress level as those of the experimental group. After 14 days, a 6 mm diameter orthodontic elastic band was inserted between teeth 26 and 27 in all animals to induce the movement of these teeth. The rats were anaesthetised and exsanguinated on day 21. In both groups, tooth movement and serum calcium levels were measured. The jaws were dissected with straight scissors, and tissue blocks containing gingiva, bone and teeth were identified, fixed and demineralised. Then, the pieces were cut into semi?serial slices, stained with hematoxylin, eosin, and Mallory’s trichrome, and analysed under an Axiophot light microscope. Results: There was significantly less tooth movement in the experimental group ( ±X DP ; 0,150 mm ± 0,037) than in the control group (0,236 mm ± 0,044; P = 0,003), while there was no significant difference in serum calcium levels between the two groups (control ±X DP ; 9,53 mg/dl ± 1,53; experimental 10,81 mg/dl ± 1,47; P = 0,15). Conclusion: While calcitonin did not completely inhibit osteoclast activity, it promoted orthodontic anchorage, apparently, by local action.

Application of modified articular disc anchorage in treating the perforation and rupture of temporomandibular joint disc / 华西口腔医学杂志

OBJECTIVES@#This study aimed to use modified articular disc anchorage in treating old irreducible temporomandibular joint (TMJ) disc displacement with perforation and rupture, as well as to explore its efficacy.@*METHODS@#A total of 31 patients (34 sides) with 47 TMJ disc perforations who underwent surgical treatment in the Affiliated Stomatolo-gical Hospital of Nanchang University from January 2018 to December 2021 were selected. According to the location of disc perforation, it has five types: posterior disc perforation (typeⅠ), anterior disc perforation (typeⅡ), lateral disc perforation (type Ⅲ), composite disc perforation, and destruction disc perforation. The modified methods of disc anchoring were divided into two types according to the location of the perforation. TypesⅠandⅢ disc perforation were trea-ted by posterior anchoring method. For posterior ancho-ring, a screw was implanted into the posterolateral side of the condylar neck, and the disc was fixed on the screw by horizontal mattress suture. TypeⅡdisc perforation and compo-site disc perforation combined typeⅡperforation were treated by anterior and posterior double-anchoring method. For anterior anchoring, anchor screws or holes were placed at the anterior edge of the condylar neck, and horizontal mattress suture was performed at the posterior edge of the anterior perforation with an anchor wire. The articular disc was then fixed on the anchor screws or holes. For the posterior anchoring method, it was the same as the previous one. Paired t test was used to analyze the visual analog scale (VAS), maximum interincisal opening (MIO), and TMJ disorder index (CMI) of the patient before surgery and 1, 3, and 6 months after surgery. Disk-condyle position relationship by magnetic resonance imaging and postoperative quality of life in postoperative were analyzed.@*RESULTS@#The incidence of perforation was 41.2% (14/34) in typeⅠ, 11.8% (4/34) in typeⅡ, 8.8% (3/34) in typeⅢ, 29.4% (10/34) in composite type, and 8.8% (3/34) in destruction type. The VAS, MIO, and CMI at 3, 6 months after operation significantly improved compared with those before operation (P<0.05). The effective reduction rate of disc was 96.77% (30/31). The quality of life at 6 months after surgery was 47.22±2.13, and the rate of excellent evaluation was 96.4% (27/28).@*CONCLUSIONS@#Modified articular disc anchorage achieves a good curative effect for treating temporomandibular joint disc perforation and rupture. Nevertheless, its long-term effect requires further observation.

Three-dimensional finite element study of mandibular first molar distalization with clear aligner / 华西口腔医学杂志

OBJECTIVES@#This study aimed to construct the finite element model of the mandibular first molar with the invisible appliance and explore the dentition movement characteristics of the mandibular first molar when using micro-implant anchorage and different initial positions of the first molar.@*METHODS@#Models of the mandible, tooth, periodontal membrane, and invisible appliance were constructed using cone beam computed tomography (CBCT) data. The two groups were divided into the non-anchorage group and the micro-implant group (between the roots of the first molar and the second molar) based on whether the elastic traction of the micro-implant was assisted or not. The two groups were divided into the following conditions based on the starting position of the first molar: Working condition 1: the distance between the first molar and the second premolar was 0 mm; working condition 2: the distance between the first molar and the second premolar was 1 mm; working condition 3: the distance between the first molar and the second premolar was 2 mm; working condition 4: the distance between the first molar and the second premolar was 3 mm. The data characte-ristics of total displacement and displacement in each direction of dentition were analyzed.@*RESULTS@#In the non-ancho-rage group, all the other teeth showed reverse movement except for the first molar which was moved distally. Meanwhile, in the micro-implant group, except for a small amount of mesial movement of the second molar in wor-king condition 1, the whole dentition in other working conditions presented distal movement and anterior teeth showed lingual movement, among which the distal displacement of the first molar in working condition 4 was the largest. With the change of the initial position of the first molar to the distal, the movement of the first molar to the distal, the premolar to the mesial, and the anterior to the lip increased, while the movement of the second molar to the mesial decreased.@*CONCLUSIONS@#The micro-implant can effectively protect the anterior anchorage, increase the expression rate of molar distancing, and avoid the round-trip movement of the second molar. The initial position of the first molar movement is related to the amount of distancing and the remaining tooth movement.

Mechanical Properties of Mini-Implants Used in Extra-Radicular Anchorage

ABSTRACT Objective: To evaluate the mechanical properties of mini-implants (MIs) manufactured from stainless steel and compare them with conventional titanium-aluminum-vanadium alloy MIs. Material and Methods: The following groups were formed: G1 (n=24), 8×1.5 mm steel MIs; G2 (n=24), 12×2.0 mm steel MIs; and G3 (n=24), 10×1.5 mm titanium MIs. The 72 MIs were inserted in the infra zygomatic crest region of the maxilla and retromolar trigone in the jaw of 10 pigs. Pull-out, insertion torque, fracture and percussion tests were performed in order to measure the tensile strength, primary stability and fracture strength of MIs. A digital torque gauge was used to measure insertion and fracture torque, a universal mechanical testing machine was used for pull-out testing and a periotest device was used to measure the micromovement of MIs. For morphological and MI component evaluation, scanning electron microscopy (SEM) was performed. D'Agostino & Pearson, Kruskal-Wallis, and Dunn post-hoc and normality tests were used. Results: G2 insertion and fracture torques were significantly higher than G1 and G3 insertion and fracture torques (p<0.05). The pull-out and percussion tests presented similar values among the groups. SEM revealed that the fracture point was predominantly on the fourth thread for steel MIs (G1 and G2) and on the seventh thread for titanium-aluminum-vanadium MIs (G3). Conclusion: The mechanical properties of stainless steel MIs are superior to those of titanium-aluminum-vanadium alloy MIs.

Evaluation of maxillary canine and molar movement during the first phase of extraction space closure: a multilevel analysis

ABSTRACT Objective: This study was designed to analyze and compare the cusp and apex movements of the maxillary canines and first molars during canine retraction in the first step of extraction space closure, and to evaluate if these teeth follow a curvilinear (acceleration and/or deceleration) movement rate. Material and Methods: Twenty-five patients (23.3 ± 5.1 years of age) were enrolled. The retraction of the maxillary canines was accomplished using nickel-titanium closed coil springs (100gf) on 0.020-in stainless steel archwire. Oblique cephalograms were traced and superimposed on the anatomic best fit of the maxilla (before the retraction [T0], and after one month [T1], three [T3], five [T5] and seven [T7] months). Statistics was based in a normally distributed data. Multilevel procedures were used to derive polynomials for each of the measurements. Student's t-test and one-way repeated measures ANOVA were conducted. The level of significance of 5% was adopted. Results: Canine cusps and apexes did not follow a quadratic curve regarding horizontal movement (neither accelerate nor decelerate). Canine and molar cusps showed more horizontal movement than apexes (4.80 mm vs. 2.78 mm, and 2.64 mm vs. 2.17 mm, respectively). Conclusions: Canine did not accelerate or decelerate overtime horizontally; the cusps and apexes of the canines and molars showed more horizontal movement and larger rate at the beginning of canine retraction, followed by significantly smaller and constant movement rate after the first month.

RESUMO Objetivo: O objetivo deste estudo foi analisar a movimentação das cúspides e dos ápices de caninos e primeiros molares superiores durante a retração de caninos na primeira fase do fechamento do espaço pós-extração, e avaliar se esses dentes apresentam mudança na taxa de movimentação (aceleração e/ou desaceleração). Material e Métodos: Vinte e cinco pacientes (idade = 23,3 ± 5,1 anos) foram incluídos. A retração dos caninos superiores foi realizada com molas helicoidais fechadas de níquel-titânio (100gf) em arco 0,020" de aço inoxidável. Foram feitos traçados cefalométricos de telerradiografias oblíquas e sobrepostos ao melhor ajuste anatômico da maxila (antes da retração [T0]; após um mês [T1], três meses [T3], cinco meses [T5] e sete meses [T7]). A estatística foi baseada em dados com distribuição normal. Procedimentos multiníveis foram usados para derivar polinômios para cada uma das medidas. Teste t de Student e ANOVA de uma via para medidas repetidas foram realizados, adotando-se um nível de significância de 5%. Resultados: As cúspides e os ápices dos caninos não seguiram uma curva quadrática em relação ao movimento horizontal (sem aceleração ou desaceleração). As cúspides dos caninos e molares apresentaram mais movimento horizontal do que os ápices (4,80 mm vs. 2,78 mm e 2,64 mm vs. 2,17mm, respectivamente). Conclusões: A movimentação horizontal dos caninos não acelerou ou desacelerou ao longo do tempo; as cúspides e os ápices dos caninos e molares apresentaram maior movimento horizontal e maior taxa de movimentação no início da retração dos caninos, seguida por uma taxa de movimentação significativamente menor e constante após o primeiro mês.

Short-term assessment of pain and discomfort during rapid maxillary expansion with tooth-bone-borne and tooth-borne appliances: randomized clinical trial

ABSTRACT Objective: The aim of this randomized clinical trial was to evaluate and compare, during the first week of rapid maxillary expansion (RME), the impact caused by two types of appliances: Hyrax and Hybrid Hyrax. Methods: Forty-two patients who met the eligibility criteria (aged 11-14 years, with transverse maxillary deficiency, posterior crossbite, and presence of maxillary first premolars and first permanent molars) were selected and randomly divided into two groups: TBB GROUP (tooth-bone-borne expander), treated with Hybrid Hyrax (12 females and 9 males, mean age 13.3 ± 1.3 years), and TB GROUP (tooth-borne expander), treated with Hyrax (5 females and 16 males, mean age 13.3 ± 1.4 years). Pain and discomfort were assessed in two times: after the first day of activation (T1) and four days after, by means of the numerical rate scale and the instrument MFIQ (Mandibular Functional Impairment Questionnaire). Descriptive statistics and the Mann-Whitney test were used for comparison between groups and between sexes. A 5% significance level was adopted. Results: Both appliances had a negative impact, generating pain and discomfort, and reducing functional capacity. However, the scores obtained were of low intensity and no significant differences were observed between the groups. Considering sexes, there were statistically significant differences, with the female sex presenting higher scores for pain and functional limitation. Conclusions: Despite causing impact in pain and increase in the functional limitation, these changes were of low intensity, with no statistical difference between the groups. Females were more sensitive to the impact caused by the RME.

RESUMO Objetivo: O objetivo deste ensaio clínico randomizado foi avaliar e comparar, durante a primeira semana de expansão rápida da maxila (ERM), o impacto causado por dois tipos de aparelhos: Hyrax e Hyrax Híbrido. Métodos: Quarenta e dois pacientes que atendiam aos critérios de seleção (idade de 11 a 14 anos, com deficiência transversal da maxila, mordida cruzada posterior e presença de primeiros pré-molares e primeiros molares permanentes superiores) foram selecionados e divididos aleatoriamente em dois grupos: Grupo DOS (expansor dento-osseossuportado), tratado com Hyrax Híbrido (12 mulheres e 9 homens, idade média 13,3 ± 1,3 anos), e Grupo DS (expansor dentossuportado), tratado com Hyrax (5 mulheres e 16 homens, idade média de 13,3 ± 1,4 anos). A dor e o desconforto foram avaliados em dois momentos: após o primeiro dia de ativação (T1) e após quatro dias, por meio da escala de frequência numérica e do instrumento MFIQ (Questionário de Limitação Funcional Mandibular). A estatística descritiva e o teste de Mann-Whitney foram utilizados para comparação entre os grupos e entre os sexos. Adotou-se nível de significância de 5%. Resultados: Ambos os aparelhos tiveram impacto negativo, gerando dor e desconforto e reduzindo a capacidade funcional. No entanto, os escores obtidos foram de baixa intensidade e não foram observadas diferenças significativas entre os grupos. Considerando os sexos, houve diferenças estatisticamente significativas, com o sexo feminino apresentando maiores escores para dor e limitação funcional. Conclusões: Apesar de causar impacto na dor e aumento na limitação funcional, essas alterações foram de baixa intensidade, sem diferença estatística entre os grupos. As mulheres foram mais sensíveis ao impacto causado pela ERM.

Does leukocyte-platelet-rich fibrin (L-PRF) cause long term acceleration in the rate of canine retraction? A split-mouth, two-arm parallel group, randomized control trial

ABSTRACT Objective: The present study was conducted to investigate the effects of leukocyte-platelet-rich fibrin (L-PRF) on the rate of maxillary canine retraction for a period of 5 months. Methods: A split-mouth study was conducted on 16 subjects (9 males and 7 females; age range 17-25 years; mean age, 21.85±2.45 years) who required therapeutic extraction of bilateral maxillary first premolars. After the initial leveling and alignment, L-PRF plugs were placed in a randomly selected extraction socket (Experimental Group), and the other side served as a control (Control Group). Canine retraction was carried out by the activation of nickel-titanium (NiTi) closed-coil springs delivering 150 g of force. The rates of canine movement, canine rotation, tipping, root resorption, and molar movement were assessed at monthly intervals for five months (T0-T5). Pain, swelling and discomfort accompanying the procedure were assessed using a Likert scale. Results: The study revealed a significant increase in the rate of canine movement on the experimental side in the first two months, and significant molar anchorage loss was observed only in the first month for control side. There were no statistically significant differences between the groups regarding canine rotation, tipping, probing depth, root resorption, and pain perception. Conclusions: The use of L-PRF plugs in extraction sockets considerably enhanced the rate of canine movement only in the first two months, and long-term efficacy was not observed in this study.

RESUMO Objetivo: O presente estudo foi realizado para investigar os efeitos da fibrina rica em leucócitos e plaquetas (L-PRF) na taxa de retração do canino superior, durante um período de cinco meses. Métodos: Um estudo de boca dividida foi realizado em 16 indivíduos (9 homens e 7 mulheres; faixa etária de 17 a 25 anos; idade média de 21,85 ± 2,45 anos) que precisavam de extração terapêutica dos primeiros pré-molares superiores de ambos os lados. Após o nivelamento e o alinhamento iniciais, os plugs de L-PRF foram colocados em um alvéolo pós-extração, selecionado aleatoriamente (Grupo Experimental), e o outro lado serviu como controle (Grupo Controle). A retração do canino foi realizada pela ativação de molas fechadas de níquel-titânio (NiTi) com 150 g de força. As taxas de movimentação do canino, rotação, inclinação e reabsorção radicular do canino e movimentação do molar foram avaliadas em intervalos mensais durante cinco meses (T0-T5). A dor, o inchaço e o desconforto após o procedimento foram avaliados por meio de uma escala de Likert. Resultados: O estudo revelou um aumento significativo na taxa de movimentação do canino no lado experimental nos dois primeiros meses, e uma perda significativa de ancoragem do molar foi observada apenas no primeiro mês no lado controle. Não houve diferenças estatisticamente significativas entre os grupos, com relação à percepção da dor e rotação, inclinação, profundidade de sondagem e reabsorção radicular do canino. Conclusões: O uso de plugs de L-PRF em alvéolos pós-extração aumentou consideravelmente a taxa de movimentação do canino apenas nos dois primeiros meses, não sendo observada uma eficácia em longo prazo.

Assessing the reliability of ChatGPT: a content analysis of self-generated and self-answered questions on clear aligners, TADs and digital imaging

ABSTRACT Introduction: Artificial Intelligence (AI) is a tool that is already part of our reality, and this is an opportunity to understand how it can be useful in interacting with patients and providing valuable information about orthodontics. Objective: This study evaluated the accuracy of ChatGPT in providing accurate and quality information to answer questions on Clear aligners, Temporary anchorage devices and Digital imaging in orthodontics. Methods: forty-five questions and answers were generated by the ChatGPT 4.0, and analyzed separately by five orthodontists. The evaluators independently rated the quality of information provided on a Likert scale, in which higher scores indicated greater quality of information (1 = very poor; 2 = poor; 3 = acceptable; 4 = good; 5 = very good). The Kruskal-Wallis H test (p< 0.05) and post-hoc pairwise comparisons with the Bonferroni correction were performed. Results: From the 225 evaluations of the five different evaluators, 11 (4.9%) were considered as very poor, 4 (1.8%) as poor, and 15 (6.7%) as acceptable. The majority were considered as good [34 (15,1%)] and very good [161 (71.6%)]. Regarding evaluators' scores, a slight agreement was perceived, with Fleiss's Kappa equal to 0.004. Conclusions: ChatGPT has proven effective in providing quality answers related to clear aligners, temporary anchorage devices, and digital imaging within the context of interest of orthodontics.

RESUMO Introdução: A Inteligência Artificial (IA) é uma ferramenta que já faz parte de nossa realidade, e esta é uma oportunidade de entendermos como ela pode ser útil na interação com os pacientes e no fornecimento de informações valiosas sobre Ortodontia. Objetivo: O objetivo deste estudo foi avaliar a precisão do ChatGPT em responder a perguntas sobre Alinhadores transparentes, Dispositivos de ancoragem temporária, e Imagens digitais em Ortodontia. Métodos: 45 perguntas e respostas foram geradas pelo ChatGPT 4.0 e analisadas separadamente por cinco ortodontistas que, de forma independente, avaliaram a qualidade das informações fornecidas, usando uma escala de Likert, na qual pontuações mais altas indicavam uma maior qualidade das informações (1 = muito ruim; 2 = ruim; 3 = aceitável; 4 = bom; 5 = muito bom). Aplicou-se o teste H de Kruskal-Wallis (p < 0,05) e comparações pareadas post-hoc com correção de Bonferroni. Resultados: Das 225 avaliações dos cinco avaliadores diferentes, 11 (4,9%) foram consideradas como muito ruins, 4 (1,8%) como ruins, e 15 (6,7%) como aceitáveis. A maioria foi considerada boa [34 (15,1%)] ou muito boa [161 (71,6%)]. Com relação às pontuações dos avaliadores, percebeu-se uma leve concordância, com o Kappa de Fleiss igual a 0,004. Conclusões: O ChatGPT mostrou eficácia em fornecer respostas de qualidade para questões relacionadas a Alinhadores transparentes, Dispositivos de ancoragem temporária e Imagens digitais.

Assessment of influence of facemask treatment with skeletal anchorage on the temporomandibular joint using magnetic resonance imaging: a preliminary study

ABSTRACT Objective: The aim of the study was to investigate the influence of facemask treatment with skeletal anchorage on the temporomandibular joint (TMJ) using magnetic resonance imaging (MRI), in patients with Class III malocclusion, accompanied by maxillary retrusion. Methods: Fifteen patients with a mean age of 12.1±1.43 years were included in the study. All patients were treated using facemask with skeletal anchorage after eight weeks of Alternate Rapid Maxillary Expansion and Constriction (Alt-RAMEC) protocol. Magnetic resonance imaging was performed before and immediately after facemask treatment for TMJ evaluation. Disc position, condylar translation, degenerative changes of the condyles, and joint effusion were evaluated. To assess whether the alterations associated with the treatment were statistically significant, McNemar and marginal homogeneity tests were used. Results: After facemask treatment, a statistically significant change was observed in the disc position (an anterior disc displacement with/without reduction in five TMJs) (p<0.05). The alteration in the condylar translation was not statistically significant (p>0.05). This treatment did not cause degenerative changes of the condyles or effusion in any of the TMJs. Conclusion: Facemask treatment with skeletal anchorage following the Alt-RAMEC protocol had a minimal influence on the TMJ, only by means of disc position, which was not negligible. Long-term results of such treatment are required for following up the changes observed in the TMJs.

RESUMO Objetivo: O objetivo desse estudo foi investigar a influência do tratamento com máscara facial com ancoragem esquelética na articulação temporomandibular (ATM), por meio de ressonância magnética (RM), em pacientes com má oclusão de Classe III acompanhada de retrusão maxilar. Métodos: Quinze pacientes com idade média de 12,1±1,43 anos foram incluídos no estudo. Todos os pacientes foram tratados com máscara facial com ancoragem esquelética após oito semanas de protocolo de Expansão Rápida da Maxila e Constrição Alternadas (Alt-RAMEC). Os exames de ressonância magnética foram realizados antes e imediatamente após o tratamento com máscara facial, para avaliação da ATM. Foram avaliados posição do disco, translação condilar, alterações degenerativas dos côndilos e derrame articular. Os testes de McNemar e de homogeneidade marginal foram utilizados para avaliar se as alterações associadas ao tratamento foram estatisticamente significativas. Resultados: Após o tratamento com máscara facial, uma mudança estatisticamente significativa foi observada na posição do disco (deslocamento anterior do disco com/sem redução em cinco ATMs) (p<0,05). A alteração na translação condilar não foi estatisticamente significativa (p>0,05). Esse tratamento não causou alterações degenerativas dos côndilos ou derrame em qualquer das ATMs. Conclusão: O tratamento com máscara facial com ancoragem esquelética ápós o protocolo Alt-RAMEC teve uma influência mínima na ATM, apenas quanto à posição do disco, que não foi desprezível. Resultados em longo prazo desse tratamento são necessários para acompanhar as mudanças observadas nas ATMs.

Stress distribution in lower second molar mesialization using mini-implants: a pilot study using 3D finite element analysis / Distribuição de tensões na mesialização do segundo molar inferior usando mini-implantes: um estudo piloto usando análise de elementos finitos 3D

Objective: to analyze the stress distribution in a 3D model that simulates second molar mesialization using two different types of mini-implants. Material and Methods: a mandible bone model was obtained by recomposing a computed tomography performed by a software program. The cortical and trabecular bone, a lower second molar, periodontal ligament, orthodontic tube, resin cement and the mini-implants were designed and modeled using the Rhinoceros 4.0 software program. The characteristics of self-drilling orthodontic mini-implants were: one with 7 mm length, 1 mm transmucosal neck section and 1.6 mm diameter and another with 5 mm length and 1.5 mm diameter. A total of 235.161 and 224.505 elements were used for the mesh. These models were inserted into the bone block and then subjected to loads of 200 cN (centinewton). The results were calculated and analyzed by the Ansys 17.0 software program for qualitative verification through displacement and maximum principal stress maps. Results: it was possible to observe that the periodontal ligament presented low displacement and stress values. However, the physiological values presented are among those capable to provide orthodontic movement, with compression and tensile area visualization staggered between 0.1 and -0.1 MPa (megapascal). Conclusion: within the limitations of the study, the mini-implants tested showed similar results where the load on the tooth allowed dental displacement (molar mesialization), with a tendency to rotate it, theoretically allowing the second molar to take the location of the first molar. (AU)

Objetivo: analisar a distribuição de tensões em um modelo 3D que simula a mesialização do segundo molar usando dois tipos diferentes de mini-implantes. Material e Métodos: um modelo de osso mandibular foi obtido por recomposição de uma tomografia computadorizada realizada por um software. O osso cortical e trabecular, um segundo molar inferior, ligamento periodontal, tubo ortodôntico, cimento resinoso e os mini-implantes foram projetados e modelados no software Rhinoceros 4.0. As características dos mini-implantes ortodônticos auto perfurantes foram: um com 7 mm de comprimento, 1 mm de secção transmucosa e 1,6 mm de diâmetro e outro com 5 mm de comprimento e 1,5 mm de diâmetro. Para a malha, foram utilizados 235.161 e 224.505 elementos. Esses modelos foram inseridos no bloco ósseo e então submetidos a cargas de 200 cN (centinewton). Os resultados foram calculados e analisados pelo software Ansys 17.0 para verificação qualitativa por meio de mapas de deslocamento e tensões máximas principais. Resultados: foi possível observar que o ligamento periodontal apresentou baixos valores de deslocamento e tensões. Porém, os valores fisiológicos apresentados são capazes de proporcionar movimentação ortodôntica, com visualização da área de compressão e tração escalonada entre 0,1 e -0,1 MPa (megapascal). Conclusão: dentro das limitações do estudo, os mini-implantes testados apresentaram resultados semelhantes onde a carga sobre o dente permitiu o deslocamento dentário (mesialização do molar), com tendência a girá-lo, permitindo teoricamente que o segundo molar ocupe do lugar do primeiro molar (AU)

Class III treatment with mini-implants anchorage in young adult patients: short and long-term results

ABSTRACT Introduction: Class III malocclusion should be intercepted and treated at early age, to prevent the necessity of future complex and expensive procedures. The orthopedic facemask therapy has the goal to achieve skeletal changes, minimizing side effects on dentition. The use of skeletal anchorage, combined with Alternate Rapid Maxillary Expansion and Constriction (Alt-RAMEC) protocol, may be effective in treating a greater number of growing Class III patients. Objective: To summarize the existing evidence-based literature on Class III malocclusion treatment in young adult patients, and to illustrate its application and effectiveness, by presenting an emblematic case report. Conclusion: The resolution of the present case, its long-term follow up, along with the studies conducted on a larger sample, demonstrate the effectiveness of the strategic combination of orthopedic and orthodontic treatments by using an hybrid rapid palatal expander and Alt-RAMEC protocol for treating Class III malocclusions in adult patients.

RESUMO Introdução: A má oclusão de Classe III deve ser interceptada e tratada em idade precoce, a fim de evitar uma futura necessidade de procedimentos complexos e invasivos. O tratamento com máscara facial ortopédica tem o objetivo de obter alterações esqueléticas, minimizando os efeitos colaterais na dentição. O uso de ancoragem óssea em mini-implantes, associada ao protocolo Alt-RAMEC (Alternate Rapid Maxillary Expansion and Constriction) pode ser eficaz no tratamento de um grande número de pacientes Classe III em crescimento. Objetivo: Realizar uma síntese da literatura baseada em evidência sobre o tratamento da má oclusão de Classe III em pacientes adultos jovens, e ilustrar sua aplicação e eficácia por meio do relato de um caso emblemático. Conclusão: A resolução e o acompanhamento em longo prazo do caso apresentado, juntamente com estudos conduzidos em uma amostra maior, demonstram a eficácia da combinação estratégica dos tratamentos ortopédico e ortodôntico usando um expansor palatal híbrido e o protocolo Alt-RAMEC para corrigir a má oclusão de Classe III em pacientes adultos.

ANCHORAGE PREPARATION FOR VARIOUS ORTHODONTIC TREATMENT

There are many kinds of orthodontic movements that make the clinical schedule a genuine test. With the appearance of the skeletal anchorage, it became more straightforward to take care of numerous issues, like anchorage, tipping, interruption among others. The reason for this article was to survey outright anchorage, including signs, implantation site, and any kind of orthodontic element

CBCT study on the safe location of palatal microscrew implant anchorage nail between maxillary first and second molars / 口腔疾病防治

Objective@#Conebeam CT (CBCT) was used to measure the palatine between the maxillary first and second molars. The proximal and distal palatal widths of the maxillary first and second molar and the palatal mucosal thickness and bone tissue thickness when microscrew implant anchorage nail were implanted at different angles provided a reference for the clinical selection of microscrew implant placement.@* Methods@#The image data of 90 adult patients were selected as the research object, and the jaw bone was reconstructed by scanning. In maxillary palatine, selection of distances at 12 mm, 14 mm, 16 mm, and 18 mm from the palatal apex of maxillary first molar between the maxillary first and second molar were used as measurement, measured the proximal and distal palatal widths of maxillary first and second molar and the palatal mucosal thickness and bone tissue thickness when microscrew implant anchorage nails were implanted at 30 °, 45 °, 60 °, and 90 °. SPSS 26.0 software was used for one-way ANOVA and LSD pair comparison. @*Results@#The larger the angle of the microscrew implant anchorage nail was, the smaller the proximal and distal medial widths between the maxillary first and second molar, and the difference was statistically significant (P < 0.05). Compared with the 90° direction, the proximal and distal medial widths of the microscrew implant anchorage nail were larger in the 60° direction. The greater the angle of implantation, the smaller the mucosal thickness and the greater the bone tissue thickness, and the results showed a significant difference (P < 0.001). Compared with the direction of 30° and 45°, the mucosal thickness at the direction of 60° was smaller, and the bone tissue thickness was larger. The higher the position of the microscrew implant anchorage nail, the greater the width of the proximal and distal medial, and the difference was statistically significant (P < 0.05). Compared with the positions 12 and 14 mm from the palatal tip, the proximal and distal medial widths of the microscrew implant anchorage nail were larger. The higher the implant position was, the greater the mucosal thickness and the smaller the bone tissue thickness. The results showed a significant difference (P < 0.001). Compared with the position of 18 mm from the palatal tip of the maxillary first molar, the mucosal thickness was smaller and the bone tissue thickness was larger.@*Conclusion@#It is most appropriate to implant microscrew implant anchorage nail at least 10 mm in length in the direction of 60° at the palatal apex 16 mm from the maxillary first molar in palatine between the first and second molar.

The Influence of Different Traction Hooks on Tooth Movement During Distalization of the Lower Dentition: A Finite Element Analysis / 医用生物力学

Objective To study stress distributions of lower dentition distally moved with miniscrews in external oblique line area when the traction hooks with different lengths were placed at different positions by the three-dimensional (3D) finite element method. Methods Based on cone beam computed tomography (CBCT) data from a patient, traction hooks with the heights of 2 mm and 7 mm were constructed and fixed between the lateral incisors and the canine brackets, as well as between the canines and the first premolar brackets. Four kinds of 3D finite element models of full dentition distally moved with miniscrews were constructed. The 3 N traction force was loaded between the traction hook and the miniscrews. The maximum von Mises stress and initial displacement of the mandibular teeth and dentition under four working conditions were analyzed. ResultsWhen the traction hook with 7 mm-height was placed between the lateral incisor and the canine, the lower central incisor rotated clockwisely, with the crown moving labially and the root moving lingually. But under the other three working conditions, the central incisor rotated counterclockwisely, and the crown and root moved lingually. When the traction hook with 7 mm-height was placed between the canine and the first premolar, the lower canine crown moved proximally. But under the other three working conditions, both the crown and root moved distally. Under four working conditions, the mandibular molars all rotated counterclockwisely,with the crown and root moving distally. Conclusions Through 3D finite element analysis, biomechanical mechanism of the effect of different traction hooks on mandibular tooth movement during distalization of the lower dentition was elucidated.With full understanding of the biomechanical mechanism, proper selection for length and placement of the traction hook can achieve distal movement of the entire mandibular dentition more efficiently.

Efficacy of vertical control by using mini-implant anchorage in maxillary posterior buccal area for Angle class Ⅱ extraction patients / 北京大学学报(医学版)

OBJECTIVE@#To investigate the efficacy of vertical control by using conventional mini-implant anchorage in maxillary posterior buccal area for Angle class Ⅱ extraction patients.@*METHODS@#Twenty-eight Angle class Ⅱ patients [9 males, 19 females, and age (22.6±2.8) years] were selected in this study. All of these patients were treated by using straight wire appliance with 4 premolars extraction and 2 mini-implant anchorage in maxillary posterior buccal area. In this study, the self-control method was used to measure and analyze the lateral radiographs taken before and after orthodontic treatment in each case, the main cephalometric analysis items were related to vertical changes. The digitized lateral radiographs were imported into Dolphin Imaging Software (version 11.5: Dolphin Imaging and Management Solutions, Chatsworth, California, USA), and marked points were traced. Each marked point was confirmed by two orthodontists. The same orthodontist performed measurement on the lateral radiographs over a period of time. All measurement items were required to be measured 3 times, and the average value was taken as the final measurement result.@*RESULTS@#Analysis of the cephalometric radiographs showed that, for vertical measurements after treatment, the differences of the following measurements were highly statistically significant (P < 0.001): SN-MP decreased by (1.40±1.45) degrees on average, FMA decreased by (1.58±1.32) degrees on average, the back-to-front height ratio (S-Go/N-Me) decreased by 1.42%±1.43% on average, Y-axis angle decreased by (1.03±0.99) degrees on average, face angle increases by (1.37±1.05) degree on average; The following measurements were statistically significant (P < 0.05): the average depression of the upper molars was (0.68±1.40) mm, and the average depression of the upper anterior teeth was (1.07±1.55) mm. The outcomes indicated that there was a certain degree of upper molar depression after the treatment, which produced a certain degree of counterclockwise rotation of the mandibular plane, resulting in a positive effect on the improvement of the profile.@*CONCLUSION@#The conventional micro-implant anchorage in maxillary posterior buccal area has a certain vertical control ability, and can give rise to a certain counterclockwise rotation of the mandible, which would improve the profile of Angle Class Ⅱ patients.