Caracterización morfológica de caninos en premolares, un caso de anodoncia parcial de caninos maxilares / Morphological characterization of canine teeth done in first bicuspid, a maxillary canine partial anodontia case report

En este informe de caso clínico se muestra el tratamiento exitoso de un paciente con anodoncia parcial de órganos dentales 13 y 23 debido a que fueron extraídos por presentar impactación y mal pronóstico de tracción. En este artículo se presenta un paciente masculino de 29 años clase I esquelética con un perfil convexo, maloclusión de clase III, overjet disminuido, ausencia de guías funcionales, discrepancia oseodentaria positiva en arcada superior y negativa en arcada inferior. El tratamiento se realizó con extracciones de los órganos dentales 34 y 44 para nivelar las discrepancias óseo dentarias interarcadas, se llevó a cabo mediante un cierre de espacios recíproco por medio de cadenas elásticas para ambas arcadas, con lo que se logró crear un overjet y overbite adecuados. La creación de las guías caninas funcionales se consiguió mediante el cambio de morfología de los órganos dentales 14 y 24, los cuales fueron llevados a la posición de los caninos ausentes. El tiempo total de tratamiento para este paciente fue de 24 meses. Se realizaron ameloplastias positivas, la aplicación de agregados de resina para mejorar la funcionalidad y proveer salud articular. Se sugiere que ante casos de anodoncia de caninos en la arcada superior, un tratamiento favorable se puede llevar a cabo mediante el cierre de espacios, la caracterización morfológica de los caninos ausentes mediante ameloplastias positivas en premolares (AU)

This case report shows the successful treatment of a patient with partial anodontia of dental organs 13 and 23 because they have been extracted due to present impactation and poor traction prognosis. This article presents a 29-year-old male class I skeletal patient with convex profile, class III malocclusion, overjet reduction, absence of functional guidance, positive bone-teeth discrepancy in the upper arch and negative in the lower arch. The treatment was carried out with the extractions of the dental organs 34 and 44 for correcting oral dental discrepancies between upper and lower arches; it was done using reciprocal closing of spaces by using elastic chains for both arches in order to achieve a suitable overjet and overbite. The creation of the canine guides was achieved by changing the morphology of the dental organs 14 and 24, which were taken to the position of the absent canines. The total treatment timing for this patient was 24 months. Positive ameloplasties were performed by application of resin aggregates to improve functionality and provide joint health. A favorable treatment for these kinds of cases of canine anodontics in the upper arch is carried out by closing spaces and the morphological characterization of the absent canines by positive in-premolar ameloplasties (AU)

Difference in Orthodontic Patients' Perceptions of Essix and Hawley Retainers

Abstract Objective: To determine differences in how orthodontic patients perceive the aesthetics relating to the use of Essix and Hawley retainers. Material and Methods: Photographs of a female patient using an Essix retainer and a Hawley retainer, respectively, were assessed by 70 orthodontic patients aged between 21 and 55 years. All participants were provided with the same images of the two retainer types being worn and were asked to grade the aesthetics of each retainer using a visual analog scale. The significance of differences in orthodontic patient perceptions of aesthetics in the use of Essix and Hawley Retainers in the young adult and adult age groups were tested using the Mann-Whitney test with assumed significance p<0.01. Results: There were differences in participants' perceptions between the two retainers that were statistically significant, with responses varying between young adults aged 21 to 35 years and adults aged 36 to 55 years. According to the VAS, the two retainers' average scores in the total population are 82 for Essix Retainer and 60 for Hawley Retainer in both groups. Conclusion: The Essix retainer as a retention appliance is considered more aesthetically pleasing than the Hawley retainer among both young and middle-aged adults.

Retenciones múltiples. Reporte de un caso / Multiple retention. Case report

RESUMEN La retención dentaria es común encontrarla en la clínica de ortodoncia, los caninos maxilares son los de mayor solicitud de tratamiento por su importancia estética. Sin embargo, no es frecuente la retención de dientes temporales. Su etiología no está bien definida pero se considera de carácter multifactorial. Se presentó una paciente del sexo femenino de 12 años y medio de edad, con ausencia de 15 y 13, presencia de 53 y mesogresión del 16. Al examen radiográfico se observó retención de 55, 15 y 13, este último en transposición incompleta con el 12. Después de un profundo análisis se decidió exéresis del 55 y alineación al arco dentario de 15 y 13, mediante colocación de un dispositivo, con el empleo del sistema de cementado directo en el acto quirúrgico. Se estableció una oclusión funcional y estética aceptable, con particular cuidado de la integridad de los dientes vecinos y sus tejidos blandos. Las retenciones constituyen maloclusiones dentarias complejas y de difícil pronóstico y tratamiento, más aún cuando son múltiples. Se requiere de estudio y tratamiento multidisciplinario (AU).

ABSTRACT It is common to find teeth retention in Orthodontics clinic; maxillary canines, due to their esthetical importance, are the ones the patients ask to be treated more frequently. Nevertheless, temporary teeth retention is not frequent. Its etiology is not clear, but it is considered multifactorial. The authors present the case of a female patient, aged 12 years and a half, without 15 and 13 teeth, presence of 53 and mesogression of 16. At the radiographic examination, the retention of 55, 15 and 13 was found, and also the incomplete transposition of 13 and 12. After deeply analyzing the case, the orthodontists decided the removal of 55 and aligning 15 and 13 to dental arch, placing a device with the system of direct cementing at the moment of the surgery. It was established a functional occlusion and an acceptable esthetics, particularly caring for the neighboring teeth and their soft tissues. Retentions are complex dental malocclusions, of difficult prognosis and treatment, mainly when they are multiple. They require study and multidisciplinary treatment (AU).

Tratamiento de Ortodoncia en un paciente con síndrome de Down / The Orthodontics treatment in a patient with Down syndrome

RESUMEN El tratamiento de Ortodoncia en pacientes con síndrome de Down, ha sido un tema debatido durante muchos años por los especialistas debido a las deficiencias físicas, mentales y a la dificultad de estos en la cooperación con el tratamiento. El objetivo de este trabajo es mostrar resultados adecuados de tratamiento ortodóncico en una paciente femenina de 12 años de edad con síndrome de Down. La niña acudió a consulta acompañada de su mamá y de su abuela solicitando tratamiento por presentar los dientes virados. En el examen clínico se observó rotación marcada de 11 y 21 mayor de 900 que afecta su estética facial. Se explicó a la familia lo difícil que podía resultar el tratamiento a esta adolescente con necesidades especiales, a la que habría que aplicar una fuerza ortodóncica que genera marcada molestia y pudiera presentarse una escasa tolerancia al dolor. La familia aseguró su cooperación. Se decidió emprender la terapia para lo cual se diseñó un plan de tratamiento en dos etapas. En una primera etapa se empleó aparatología ortodóncica removible y en una segunda etapa aparatología fija. Al concluir el tratamiento se logró resolver de manera satisfactoria el motivo de consulta con buena cooperación por parte de la paciente y su familia. El éxito del tratamiento se debió a la satisfactoria cooperación de la paciente y al establecimiento de una relación favorable ortodoncista-paciente-familia (AU).

ABSTRACT The Orthodontics treatment in patients with Down syndrome has being a theme debated by specialist during many years, due to the physical and mental deficiencies of this kind of patients and their difficulty in cooperating with the treatment. The aim of this article is showing the adequate results of the orthodontic treatment in a female patient aged 12 years with Down syndrome. The girl assisted to consultation with her mother and grandmother asking treatment for having crooked teeth. At the physical examination it was observed a remarked rotation of 11 and 21 of more than 900, affecting her facial esthetics. Doctors explained to relatives that the treatment could result very difficult to this teenager with special requirements due to the application of an orthodontic force generating great discomfort in this girl, possibly having a scarce tolerance to pain. The relatives agreed to cooperate. They decided to start the therapy, and a two-stage plan was designed. In the first stage, removable orthodontic braces were used, and fixed ones were used in the second stage. At the end of the treatment the cause of the consultation was successfully solved with a good cooperation of the patient and her relatives. The success of the treatment was achieved due to the satisfactory cooperation of the patient and the establishment of a favorable relationship orthodontist-patient-family (AU).

Removable partial dentures: eliminating retainers in the anterior zone / Prótesis parcial removible: eliminación de retenedores en la zona anterior

Abstract Introduction: one of the main factors for discomfort in users of removable partial prosthesis is the presence of visible retainers in the anterior zone. In Kennedy Class III arches, that is, exclusively dental loading pathways (in which the functional forces reach their final receptor: the alveolar bone), anterior zone retainers may be eliminated by selecting an appropriate prosthetic insertion and removal axis, and mainly by carving guiding planes that should provide retention by mechanical rubbing. This in vitro experimental study aimed to prove the hypothesis that it is possible to obtain functional retention in a dental-loading pathway removable partial prosthesis without using retainers in the anterior zone. Methods: 7 maxillary models with different types of toothless process were used. As a common characteristic, they all were classified as Kennedy Class III with partial denture arches. A Cr-Co metallic base was built for each model according to their clinical situation. Their design allowed them to be exposed to traction in a universal traction machine (Tinius Olsen H5K-S). Results: the proposed hypothesis was confirmed as expected. The traction force needed to displace the metallic bases with retainers in the anterior zone was 16.93 Newton in average. On the other hand, the metallic bases without retainers in the anterior zone showed an average of 12.84 N. The average values obtained for both groups are higher than those reported in the literature (4.903 N). Conclusions: in Class III removable partial dentures it is possible to use metallic bases with no retainers in the anterior zone.

Resumen Introducción: un factor que incomoda a los usuarios de prótesis parciales removibles es la presencia de retenedores visibles en la zona anterior. En clases III de Kennedy, es decir, vías de carga exclusivamente dentarias, sería posible eliminar los retenedores del sector anterior mediante un adecuado tallado de planos guías que brinde retención por roce mecánico y la elección de un eje de inserción y remoción protésico. Este trabajo es un diseño experimental in vitro que tiene por finalidad validar la hipótesis propuesta por nuestro equipo de investigación, que es posible obtener retención funcional en una prótesis parcial removible de vía de carga dentaria sin utilizar retenedores en el sector anterior. Métodos: se utilizaron 7 modelos maxilares en yeso tipo IV, con distinto tipo de desdentamiento, cuya característica común era que correspondían a clases III de Kennedy de arcos parcialmente desdentados. A cada modelo se le confeccionó una base metálica de Cr-Co, de acuerdo con sus características clínicas individuales, las cuales presentaron un diseño que permitió utilizarlas en una máquina de tracción universal para someterlas a fuerzas de tracción. Resultados: la fuerza de tracción necesaria para desalojar las bases metálicas que contaban con retenedores en el sector anterior fue del orden de 16,93 N en promedio. En cambio, las bases metálicas sin retenedores en el sector anterior presentaron un valor promedio para su desalojo de 12,84 N. Conclusiones: los valores promedio obtenidos para ambos grupos son superiores a los que se señala en la literatura (4,903 N) como válidos para una retención adecuadamente funcional para una prótesis parcial removible.

Periodontal parameters of two types of 3 x 3 orthodontic retainer: a longitudinal study

ABSTRACT Introduction: bonded fixed retainers are often used to stabilize the results obtained with the orthodontic treatment. It is important that they do not prejudice dental health, as they will be used for a long period. Objective: The purpose of the present study was to compare periodontal indexes between two types of bonded fixed retainers, conventional 3 x 3 plain retainer (0.8-mm orthodontic wire, bonded to the canines only) and a manufactured braided retainer (0.2 x 0.7-mm stainless steel wire, bonded to all anterior teeth) after use. Methods: a test group of 15 volunteers (aged from 18 to 25 years) used both the conventional retainer and braided retainer for six months. A randomized longitudinal study design, with a two week washout interval, was applied. The dental plaque index, gingival index and dental calculus index were evaluated. Furthermore, the calculus accumulated along the retainer wire was measured and all patients answered a questionnaire about the use, acceptance and comfort of both types of retainers. Results: the scores for plaque and gingival indexes were higher for the braided retainer (p< 0.05) on the lingual and proximal surfaces. The same occurred with the calculus index on the lingual surfaces (p< 0.05). The calculus index along wire was higher for the braided retainer (p< 0.05). All patients preferred the conventional retainer, and said that it was also more comfortable to use. Conclusion: it was concluded that the conventional retainer showed better periodontal indexes than the braided type.

RESUMO Introdução: as contenções ortodônticas fixas são amplamente utilizadas após o tratamento ortodôntico, sendo fundamental que esses dispositivos não se tornem prejudiciais à saúde dentária, já que serão usados por um longo período. Objetivo: o presente estudo teve como objetivo a avaliação periodontal da região da arcada inferior, comparando as condições de acúmulo de placa e cálculo ao longo do fio e na margem gengival, em decorrência do uso da contenção convencional (fio 0,8 mm de aço inoxidável colado apenas nos caninos) ou de uma contenção pré-fabricada com fio trançado (0,2 x 0,7 mm colado em todos os dentes anteroinferiores) após exposição ao meio bucal. Métodos: participaram do estudo 15 voluntários adultos jovens (idades entre 18 e 25 anos) que utilizaram dois tipos de contenções, por seis meses cada. Foi utilizado um modelo de estudo longitudinal, randomizado, com washout de 15 dias. Os parâmetros periodontais utilizados foram: índice gengival, índice de placa e índice de cálculo. O cálculo acumulado ao longo da contenção foi avaliado e todos os pacientes responderam a um questionário sobre o uso, aceitação e conforto de ambos os tipos de contenção. Resultados: observou-se que o índice de placa foi maior para a contenção com fio trançado (p<0,05), assim como o índice gengival (p<0,05). O mesmo ocorreu para o índice de cálculo nas faces proximais e lingual (p<0,05). O índice de cálculo ao longo do fio também foi significativamente maior para a contenção com fio trançado (p<0,05). Em relação ao questionário aplicado, 60% dos voluntários consideraram que a contenção com fio trançado foi mais desconfortável, e todos eles preferiram a contenção convencional. Conclusão: concluiu-se que a contenção convencional apresentou melhores resultados periodontais, quando comparada à contenção pré-fabricada com fio trançado.

Users' perceptions and preferences towards maxillary removable orthodontic retainers: a crossover randomized clinical trial

Abstract The aim of this study was to assess, correlate, and compare users' perceptions and preference related to maxillary removable retainers. Volunteers were recruited to use four retainer types: conventional wrap-around (CWA), wrap-around with an anterior opening (OWA), "U" wrap-around (UWA), and clear thermoplastic retainer (CT). The main outcomes were the volunteers' perceptions, evaluated with a 100-mm visual analogue scale, and their preferred retainer. The retainers were used for 21 days each (washout intervals of 7 days). Nineteen volunteers (27 ± 4.53 years) were randomly divided into four groups that used the four retainers, but with a different sequence. Perceptions were evaluated immediately after the use of each retainer and the preference at the end of the research. Repeated measures ANOVA and Friedman tests with post-hoc Tukey's test (intergroup comparisons), and Pearson and Spearman analyses (correlations between perceptions) were applied. The WA retainers did not significantly differ among themselves. The CT was rated significantly worse in speech (p ≤ 0.001), discomfort (p < 0.001), and occlusal interference (p < 0.001), and did not significantly differ from the others in esthetics. Users preferred significant more the WA retainers in comparison with the CT retainers. The occlusal interference caused by the CT was positively correlated to other perceptions, such as changes in speech and discomfort. WA retainers presented similar preference and perceptions, but were significantly better than the CT. The CT occlusal coverage appeared to be the primary cause of its rejection.

Mandibular anterior crowding: normal or pathological?

ABSTRACT The teeth become very close to each other when they are crowded, but their structures remain individualized and, in this situation, the role of the epithelial rests of Malassez is fundamental to release the EGF. The concept of tensegrity is fundamental to understand the responses of tissues submitted to forces in body movements, including teeth and their stability in this process. The factors of tooth position stability in the arch - or dental tensegrity - should be considered when one plans and perform an orthodontic treatment. The direct causes of the mandibular anterior crowding are decisive to decide about the correct retainer indication: Should they be applied and indicated throughout life? Should they really be permanently used for lifetime? These aspects of the mandibular anterior crowding and their implication at the orthodontic practice will be discussed here to induct reflections and insights for new researches, as well as advances in knowledge and technology on this subject.

RESUMO Os dentes ficam muito próximos quando estão apinhados, mas suas estruturas permanecem individualizadas e, nessa situação, o papel dos restos epiteliais de Malassez é fundamental para liberar o EGF. A tensigridade é um conceito chave para compreender as respostas dos tecidos submetidos às forças nos movimentos corporais, incluindo os dentes e sua estabilidade nesse processo. Os fatores da estabilidade de posição de um dente na arcada dentária — ou tensigridade dentária — devem ser considerados quando se planeja e finaliza um caso na prática clínica ortodôntica. As causas diretas do apinhamento dentário anteroinferior são determinantes para se refletir se a contenção deve ser mesmo indicada e aplicada por toda a vida e se, necessariamente, deve ser usada de forma permanente. Esses aspectos do apinhamento dentário anteroinferior e suas implicações na prática clínica serão aqui abordados para induzir reflexões e insights de novas pesquisas, bem como avanços no conhecimento e tecnologia sobre esse assunto.

Current situation and prospect for orthodontic thermoplastic materials / 华西口腔医学杂志

Aesthetic and comfortable transparent retainers and clear plastic appliances are becoming increasingly popular, and their components, especially thermoplastic materials, are gradually attracting widespread interest. Orthodontic thermoplastic materials are versatile polymers, and thus their properties, such as force delivery, force relaxation, and aging properties have been comprehensively studied. Meanwhile, blending modification technology has been applied for the acquisition of novel materials with enhanced characteristics. In this paper, we review the types and properties of thermoplastic materials, the development process they undergo, factors that influence their properties, and some development prospects.

Comparison between fiber-reinforced polymers and stainless steel orthodontic retainers / 대한치과교정학회지

OBJECTIVE: The aim of this study was to examine the properties of fiber-reinforced composite and stainless steel twisted retainers for orthodontic retention. METHODS: Three different span lengths (5.0, 8.0, and 14.0 mm) of fiber-reinforced composite were investigated. The three fiber-reinforced composite retainer groups were subdivided according to the storage condition (dry and wet), resulting in a total of six groups. Each stainless steel and fiber-reinforced composite group was comprised of six specimens. The three-point bending flexural test was conducted using a universal testing machine. ANOVA was used to assess differences in the maximum load and maximum stress according to the span length, material, and storage condition. Post-hoc comparisons were performed if necessary. RESULTS: The maximum stress and maximum load were significantly (p < 0.001) associated with the span length, material, and storage condition. The significant interaction between the material and span length (p < 0.001) indicated the differential effects of the material for each span length on the maximum stress and maximum load, with the difference between materials being the highest for the maximum span length. CONCLUSIONS: Our findings suggest that fiber-reinforced composite retainers may be an effective alternative for orthodontic retention in patients with esthetic concerns or allergy to conventional stainless steel wires.

Retention period after treatment of posterior crossbite with maxillary expansion: a systematic review

ABSTRACT OBJECTIVE: The aim of this systematic review was to evaluate the duration of the retention period in growing patients undergoing maxillary expansion and its relation with posterior crossbite stability. METHODS: Search strategies were executed for electronic databases Cochrane Library, Web of Science, PubMed and Scopus, which were completed on January 15, 2016. The inclusion criteria included randomized, prospective or retrospective controlled trials in growing subjects with posterior crossbite; treated with maxillary expanders; retention phase after expansion; post-retention phase of at least 6 months. The exclusion criteria were anterior crossbite, craniofacial anomalies, surgery or another orthodontic intervention; case reports; author’s opinions articles, thesis, literature reviews and systematic reviews. The risk of bias of selected articles was assessed with Cochrane risk of bias tool for RCTs and Downs and Black checklist for non-RCTs. RESULTS: A total of 156 titles/abstracts was retrieved, 44 full-texts were examined, and 6 articles were selected and assessed for their methodological quality. The retention period after maxillary expansion ranged between 4 weeks and 16 months. Fixed (acrylic plate, Haas, Hyrax and quad-helix) or removable (Hawley and Hawley expander) appliances were used for retention. CONCLUSIONS: Six months of retention with either fixed or removable appliances seem to be enough to avoid relapse or to guarantee minimal changes in a short-term follow-up.

RESUMO OBJETIVO: o objetivo da presente revisão sistemática foi avaliar a duração do período de contenção e a estabilidade do tratamento ortodôntico com expansão maxilar em pacientes em crescimento com mordida cruzada posterior. MÉTODOS: foram realizadas buscas estratégicas nas bases eletrônicas: Cochrane Library, Web of Science, PubMed e Scopus, até 15 de janeiro de 2016. Os critérios de inclusão foram: estudos clínicos controlados e randomizados, prospectivos ou retrospectivos, de pacientes em crescimento com mordida cruzada; tratados com aparelhos expansores maxilares, com fase de contenção pós-expansão e no mínimo seis meses de fase de pós-contenção. Os critérios de exclusão foram: mordida cruzada anterior, anomalias craniofaciais, cirurgia ou outro tratamento ortodôntico; relato de casos; artigos de opinião; teses; revisões de literatura e revisões sistemáticas. O risco de viés dos artigos selecionados foi avaliado a partir do Cochrane risk of bias tool para ensaios clínicos randomizados e Downs and Black checklist para ensaios clínicos não randomizados. RESULTADOS: a busca resultou em 156 títulos/resumos, sendo 44 textos examinados na íntegra. Foram selecionados 6 artigos para o acesso à qualidade metodológica. A duração do período de contenção ocorreu entre 4 semanas e 6 meses. Aparelhos fixos (aparelho em acrílico, Haas, Hyrax e quad-helix) ou removíveis (Hawley e Hawley com expansor) foram utilizados na fase de contenção. CONCLUSÃO: parece que seis meses de contenção com aparelhos fixos ou removíveis são suficientes para evitar a recidiva ou garantir mudanças mínimas em um curto período de acompanhamento pós-contenção.

Reader's Forum / 대한치과교정학회지

No abstract available.

Effects of a new type of clear overlay retainer on occlusal contacts / 대한치과교정학회지

The popularity of clear overlay retainers (CORs) has increased recently because of their advantages such as better esthetics, cost effectiveness, easy fabrication, and good compliance. However, a deficiency in posterior occlusal settling is a reported limitation of CORs. The aim of this study was to evaluate the posterior occlusal contact changes in a new type of clear orthodontic retainer called Oral-treaper (OTP), which consists of three layers and has stronger mechanical characteristics than do conventional retainers. Three patients who completed fixed orthodontic treatment received OTP as a removable retainer. Cast models were fabricated after the removal of fixed appliances (T1) and after 4 to 11 months of using the retainers (T2). We evaluated all the cast models to compare the post-orthodontic settling pattern during the use of the OTPs. The depth of occlusal contacts was evaluated using color maps. The OTP did not prevent vertical settling in all patients but resulted in an improvement in posterior occlusal contact points.

Effectiveness of two retainer types in dental and occlusal stability / Efectividad de la estabilidad dentaria y oclusal con dos tipos de retenedores

ABSTRACT Introduction: with the purpose of providing additional details on the selection of retainer type, this study sought to assess the stability of dental and occlusal position during retention phase using two types of retainers in individuals with no remnant growth who completed orthodontic treatment at the Universidad de Antioquia School of Dentistry, Universidad CES, and in private practice in Medellín in 2011. Methods: this was a controlled clinical study with a sample of 47 patients aged 15 to 45 years, randomly selected into two treatment groups: 22 patients with Essix retainer and 25 patients with Hawley plate in both arches. Cephalometric X-rays and study models were taken on all patients at baseline and six months later with monthly clinical evaluations. Results: the clinical and radiographic results showed significant differences in some tooth rotations in terms of upper intercanine distance and molar relationship, but overall there were no statistically significant differences between both retainers in the three space planes. Conclusion: there were no statistically significant differences between the retainers in a six-month evaluation period.

RESUMEN Introducción: con el propósito de ofrecer mayor evidencia sobre la selección del tipo de retenedor, este estudio pretendió evaluar la estabilidad de la posición dentaria y oclusal durante el tratamiento de retención con dos tipos de retenedores en individuos sin crecimiento remanente que finalizaron tratamiento ortodóncico en la Facultad de Odontología de la Universidad de Antioquia, de la Universidad CES y en la práctica privada en Medellín en el año 2011. Métodos: se hizo un ensayo clínico controlado con una muestra de 47 pacientes con edades entre 15 y 45 años, divididos aleatoriamente en dos grupos de tratamiento: 22 pacientes con retenedor tipo Essix y 25 pacientes con placa de Hawley en ambos arcos. A todos los pacientes se les tomó radiografía cefálica lateral y modelos de estudio, al inicio y seis meses después, y se hizo evaluación clínica mensual. Resultados: los resultados clínicos y radiográficos mostraron diferencias significativas en algunas rotaciones dentarias, en la distancia intercanina superior y en la relación molar, pero en general no se encontraron diferencias estadísticamente significativas entre los dos retenedores en los tres planos del espacio. Conclusión: no se encontraron diferencias estadísticamente significativas entre los retenedores en una evaluación a seis meses.

Comparison of wear resistance of hawley and vacuum formed retainers: an in-vitro study

Statement of Problem: As a physical property, wear resistance of the materials used in the fabrication of orthodontic retainers play a significant role in the stability and long term use of the appliances

Objectives: To evaluate the wear resistance of two commonly used materials for orthodontic retainers: Acropars OP, i.e. a polymethyl methacrylate based material, and 3A-GS060, i.e. a polyethylene based material

Materials and Methods: For each material, 30 orthodontic retainers were made according to the manufacturers' instructions and a 30×30×2 mm block was cut out from the mid- palatal area of each retainer. Each specimen underwent 1000 cycles of wear stimulation in a pin on disc machine. The depth of wear of each specimen was measured using a Nano Wizard II atomic force microscope in 3 random points of each specimen's wear trough. The average of these three measurements was calculated and considered as mean value wear depth of each specimen [micro m]

Results: The mean wear depth was 6.10micro m and 2.15micro m for 3A-GS060 and Acropars OP groups respectively. Independent t-test showed a significant difference between the two groups [p < 0.001]. The results show Polymethyl methacrylate base [Acropars] is more wear resistance than the polyethylene based material [3A-GS060]

Conclusions: As the higher wear resistance of the fabrication material can improve the retainers' survival time and its cost-effectiveness, VFRs should be avoided in situations that the appliance needs high wear resistance such as bite blocks opposing occlusal forces

Tratamiento interdisciplinario en la resolución de un caso clínico / Interdisciplinary treatment for the resolution of a clinical case

La resolución del caso clínico presentado, demuestra la importancia de la prevención como objetivo de toda acción odontológica. Los datos obtenidos a través de la anamnesis de la paciente tratada (hábito de succión del pulgar, antecedentes familiares, tabaquismo) no dejan lugar a dudas de cómo las anomalías que motivaron la consulta fueron consecuencias directas de este hábito que trajo aparejado, además, severos problemas periodontales, estéticos y funcionales asociados entre sí. La resolución obtenida debe ser considerada como bastante buena en relación al complejo problema que presentaba el caso clínico. El trabajo realizado fue muy valorado por el paciente y trajo como consecuencia una mejoría no solamente en su salud bucal, sino también en su bienestar personal y anímico. El enfoque multidisciplinario, por otra parte, permite la integración de varias ramas de nuestra profesión y los avances logrados en rehabilitación con el trabajo mancomunado de la ortodoncia, cirugía y la prótesis, brindan la posibilidad de resolver casos complejos, lo que hasta hace un tiempo era impensado. Queremos resaltar que la atención precoz de los pacientes, ya sea desde el punto de vista ortopédico-ortodóncico como desde el punto de vista periodontal, tendría que ser un objetivo primordial en nuestra salud. Este caso resume varios problemas odontológicos que podrían haberse resuelto solamente con prevención y atención precoz...

Effects of Hawley retainer and vacuum-formed retainer on articulation of Chinese speech of adult orthodontic patients: a randomized controlled trial / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study investigated the influence of Hawley retainer and vacuum-formed retainer on the articu-lation of Chinese speech of adult orthodontic patients.</p><p><b>METHODS</b>A total of 20 volunteers were recruited in this randomized controlled trial in accordance with the inclusion criteria. Participants were randomly distributed into two groups, namely, the Hawley retainer group and the vacuum-formed retainer group. Speech performance was evaluated at the following time inter-vals: before wearing retainers (T0), immediately after wearing both upper and lower retainers (T1), 24 h later (T2), 1 week later (T3), and 1 month later (T4). The phonetic parameters were acquired through the use of computer-based voice analysis software Praat version 5.4.21, and the final data were analyzed using SPSS 19.0.</p><p><b>RESULTS</b>Both retainers can influence the phonetic parameters of vowels /e/, /i/, and /ü/ and consonants /s/, /f/, /x/, /t/, /j/, and /q/. However, the Hawley retainer showed a more remarkable effect on the articulation of Chinese speech, and the distortion of /i/, /ü/, and /s/ sounds can last for more than 1 month. Nevertheless, the recovery period of the patients' phonetic function in the vacuum-formed retainer group was within 1 month.</p><p><b>CONCLUSIONS</b>Both retainers can induce distortion of some Chinese vowels and consonants in the speech of adult orthodontic patients, but the Hawley retainer can more significantly influence the articulation of Chinese speech than vacuum-formed retainer.
.</p>

Influence of the manipulation technique of acrylic resin on mechanical strength of orthodontic plates / Influencia da técnica de manipulação de resina acrilica sobre a resistencia mecanica de placas ortodonticas

The focus of this study was to test the fracture resistance of upper arch dental retainers, made by two different manipulation techniques of acrylic resin. 84 plates Wraparound type retainers were made by two different manipulation techniques forming two groups (n = 42): Group 1 (Addition Technique) and Group 2 (Pressing Technique). All the retainers were duly shaped in U form with the aid of standardized plaster cast models. During the confection process the standardizing of the retainers was conducted carefully regarding their thickness and dimensions with the aid of a gauge and a straight caliper. After confection they remained immersed in water for 24 hours at 37°C. Next, they were tested through mechanical compression until fracture in a universal mechanical testing machine. Data were analyzed by Student's t test. The significance level was set at 5% ( = 0.05). It was found that the average was of 79.12 N for Group 1 and of 77.07 N for Group 2 with a standard deviation of 17.30 N and 16.31, respectively, showing that there is no significant difference in resistance for the retainers when made through any of the two methods (P=0.788). The addition and pressure techniques of acrylic resin do not influence the resistance to compression of the upper dental retainers.

O foco deste estudo foi testar a resistência à fratura de retentores odontológicos do arco superior, feito por duas diferentes técnicas de manipulação de resina acrílica. 84 placas de retentores tipo Wraparound foram feitas por duas diferentes técnicas de manipulação que formam dois grupos (n = 42): Grupo 1 (técnica de adição) e Grupo 2 (técnica de prensagem). Todos os retentores foram devidamente moldado em forma de U, com o auxílio de modelos de gesso padronizados. Durante o processo de confecção a padronização dos retentores foi conduzida cuidadosamente em relação à sua espessura e dimensões, com o auxílio de um medidor e um compasso de calibre linear. Após a confecção eles permaneceram imersos em água por 24 horas a 37 °C. Em seguida, eles foram testados através de compressão mecânica até a fratura em uma máquina universal de ensaios mecânicos. Os dados foram analisados pelo teste t de Student. O nível de significância foi de 5% ( = 0,05). Verificou-se que a média foi de 79,12 N para o Grupo 1 e de 77,07 N para o Grupo 2, com um desvio padrão de 17,30 N e 16,31, respectivamente, indicando que não há diferença significativa na resistência para os retentores, quando feita através de qualquer um dos dois métodos (P = 0,788). As técnicas de adição e pressão de resina acrílica não influenciaram a resistência à compressão dos retentores dentárias superiores.