Accuracy of arch expansion with two thermoplastic materials in Invisalign® patients: EX30® and SmartTrack®

ABSTRACT Objective: The purpose of this retrospective study was to compare accuracy of arch expansion using two different thermoplastic materials in Invisalign aligners: EX30® (Polyethylene Terephthalate Glycol, or PETG) and SmartTrack® (polyurethane). Methods: The study sample comprised 65 adult patients consecutively treated with Invisalign from two private practices: group 1 - treated with EX30® (358 teeth) and group 2 - treated with SmartTrack® (888 teeth). Six hundred and twenty-three measurements were assessed in three digital models throughout treatment: model 1 - initial, model 2 - predicted tooth position, and model 3 - achieved position. Sixteen reference points per arch were marked and, after best alignment, 2 points per tooth were copied from one digital model to another. Linear values of both arches were measured for canines, premolars, and first molars: on lingual gingival margins and cusp tips of every tooth. Comparisons were performed by Wilcoxon and Mann-Whitney test. Results: Both termoplastic materials presented significant differences between predicted and achieved values for all measurements, except for the lower molar cusp tip in the SmartTrack® group. There is no statistical difference in the accuracy of transverse expansion between these two materials. Overall accuracy for EX30® aligners in maxilla and mandible were found to be 37 and 38%, respectively; and Smarttrack® presented an overall accuracy of 56.62% in the maxilla and 68.72% in the mandible. Conclusions: It is not possible to affirm one material expands better than the other. Further controlled clinical studies should be conducted comparing SmartTrack® and EX30® under similar conditions.

RESUMO Objetivo: O objetivo deste estudo retrospectivo foi comparar a acurácia na expansão da arcada utilizando alinhadores Invisalign com dois tipos de material termoplástico: EX30® (Polietileno Tereftalato Glicol, ou PETG) e SmartTrack® (poliuretano). Método: A amostra desse estudo incluiu 65 pacientes adultos tratados consecutivamente em dois consultórios particulares: grupo 1 - tratado com EX30® (358 dentes), e grupo 2 - tratado com SmartTrack® (888 dentes). Foram avaliadas 623 medidas em três pares de modelos digitais, ao longo do tratamento: modelo 1 - inicial, modelo 2 - posição dentária planejada, modelo 3 - posição alcançada. Foram marcados 16 pontos de referência por arcada e, após o bestfit, 2 pontos por arcada foram copiados de um modelo digital para o outro. Medidas lineares de ambas as arcadas foram aferidas para caninos, pré-molares e primeiros molares, localizadas na margem gengival lingual e ponta de cúspide de todos os dentes. Foram realizadas comparações usando os testes Wilcoxon e Mann-Whitney. Resultados: Ambos os materiais termoplásticos apresentaram diferenças significativas entre os valores planejados e alcançados em todas as medidas, exceto na ponta de cúspide dos primeiros molares inferiores do grupo SmartTrack®. Não houve diferença estatística entre esses dois materiais quanto à acurácia da expansão transversa. Em termos gerais, a acurácia dos alinhadores EX30® na maxila e mandíbula foi de 37% e 38%, respectivamente. O grupo SmartTrack® apresentou acurácia de 56,62% e 68,72% na maxila e mandíbula, respectivamente. Conclusões: Não foi possível afirmar que um material expande melhor que o outro. Estudos clínicos controlados futuros devem ser conduzidos comparando SmartTrack® e EX30® sob condições similares.

Accuracy of Invisalign® aligners in adult patients: a retrospective study of angular tooth movements

ABSTRACT Objective: This retrospective study aimed to assess the predictability of Invisalign® aligners regarding rotational, mesio-distal and buccal-lingual tip movements. Methods: Two materials were included in the analysis - EX30, used until 2013; and SmartTrack, in current use. The study comprised 56 adult patients treated with Invisalign Comprehensive. Data sample were assessed on three sets of digital models; model 1 - initial, model 2 - predicted, and model 3 - achieved. Sixty reference points were marked in each dental arch, and two reference planes assisted the superimposition. The degree of rotation, mesio-distal and buccal-lingual tip was obtained via trigonometric calculations, through a previously published validated method. The accuracy of outcomes was compared according to the types of tooth movement and teeth groups,and the influence of predetermined variables on movement accuracy was also investigated. Results: Rotation and mesio-distal tip did not present any significant difference when comparing EX30 and SmartTrack groups. Only buccal-lingual tip presented a significant difference, incisor and canine groups treated with EX30 aligners presented an increase in accuracy (p= 0.007 and p = 0.007, respectively). For each additional degree planned for rotation movements, there was an increase of 0.35° in the discrepancy, and an increase of 0.40° and 0.41° for mesio-distal and buccal-lingual tip, respectively. EX30 and SmartTrack discrepancies were compared by multilevel linear regression. Conclusion: EX30 aligners reached higher accuracy for buccal-lingual tip in anterior teeth. However, for rotation and mesio-distal tip, SmartTrack and EX30 are similarly accurate. The total amount of planned movement has a significant impact on accuracy rates, with a decrease in accuracy for every additional degree.

RESUMO Objetivo: Esse estudo retrospectivo teve como objetivo aferir a previsibilidade dos alinhadores Invisalign em relação aos movimentos de rotação e inclinações mesiodistal e vestibulolingual. Material e Métodos: Foram incluídos dois materiais nessa análise: EX30®, utilizado até 2013; e SmartTrack®, atualmente em uso. Esse estudo avaliou 56 pacientes tratados com Invisalign Comprehensive. Os dados foram avaliados em três pares de modelos digitais; modelo 1 - inicial, modelo 2 - planejado, e modelo 3 - alcançado. Foram marcados 60 pontos de referência em cada arcada, sendo a sobreposição realizada com auxílio de planos de referência. O grau de rotação e inclinações mesiodistal e vestibulolingual foi obtido por cálculos de trigonometria, usando um método validado publicado anteriormente. Os resultados foram comparados de acordo com os tipos de movimento dentário e grupos de dentes, também foi investigada a influência de variáveis predeterminadas na confiabilidade dos movimentos. Resultados: Os movimentos de rotação e inclinação mesiodistal não apresentaram diferença estatística, quando comparados os grupos EX30® e SmartTrack®. Somente a inclinação vestibulolingual apresentou diferença estatisticamente significativa, sendo que os grupos de incisivos e caninos tratados com alinhadores EX30® apresentaram um aumento na previsibilidade(p= 0,007 e p= 0,007, respectivamente). Para cada grau adicional planejado para movimento de rotação, ocorreu um aumento de 0,35° na discrepância, e aumentos de 0,40° e 0,41° para as inclinações mesiodistal e vestibulolingual, respectivamente. As discrepâncias entre EX30® e SmartTrack® foram comparadas por regressão linear multinível. Conclusão: Os alinhadores EX30® alcançaram maior previsibilidade para a inclinação vestibulolingual em dentes anteriores. No entanto, para rotação e inclinação mesiodistal, SmartTrack® e EX30® apresentaram previsibilidade similar. A quantidade total de movimento planejado apresenta influência significativa nas taxas de previsibilidade, com diminuição na acurácia para cada grau adicional.

Digital repair for a patient with limited mouth opening: a case report and literature review / 口腔疾病防治

Objective@#To explore an accurate method to obtain an intraoral model of patients with specific limited mouth opening (microstomia) due to systemic scleroderma.@*Methods@#This study followed medical ethics, and informed consent has been obtained from patients. A case of Ken's Type I mandibular dentition defect scleroderma with limited mouth opening was addressed with digital technology as the leading method combined with the traditional impression method of segmental impression. Individual trays were made based on the patient's left and right mandibular dentition, and segmented molds were obtained. Simultaneously, intraoral scanning was performed to obtain the morphological data of both the soft and hard tissues of the upper and lower mandibles. After each part of the model was obtained, the mandibular model was scanned and digitally aligned to form the final denture model, and the final removable partial denture was designed and made by computer aided design/computer aided manufacturing (CAD/CAM) technology. At the same time, combined with the literature, the diagnosis and treatment of removable partial denture in patients with limited mouth opening were retrospectively analyzed.@*Results@#The denture was well retained and achieved a good repair effect. The patients expressed satisfaction with the mastication efficiency and other functions of the denture. The findings of the literature review show that the integration of digital technology with the traditional impression method, along with computer fitting, can accurately obtain the patient's oral model and facilitate successful follow-up repairs. However, when the anterior mandibular dentition of the patient is absent, the margin of error is increased in this procedure, which deserves further exploration.@*Conclusion@#Utilizing digital technology as the leading method, combined with the traditional impression method of segmental impression, for the repair of dental defects in patients with limited mouth opening, has proven to be effective. Thus, patients report a positive medical experience with high satisfaction, indicating that this approach is worthy of clinical promotion.

Restoration of a dental defect in a patient with ectodermal dysplasia: a case report and literature review / 口腔疾病防治

Objective@#To explore the treatment options for congenitally missing teeth in patients with ectodermal dysplasia and provide a clinical reference.@*Methods@#A patient with ectodermal dysplasia with a concave midface, anterior protrusion of the chin, and underdevelopment of the lower third of the face presented with congenital loss of multiple maxillary teeth, malocclusion of the remaining teeth, congenital loss of mandibular dentition, small dental arches, and upper and lower alveolar bone hypoplasia. The patient was treated by means of a removable partial maxillary prosthesis, implants in the anterior region of the lower mandible designed with the assistance of digital guides, and bar-clamped implant-overlay prostheses. A literature review of the protocol for the treatment of this condition was also conducted.@*Results@#In addition to good retention and stability after denture wear, an excellent occlusal relationship, improvement of the patient's facial appearance, including upper and lower lip fullness, more equal balancing of the lower and middle 1/3 of the face, and improved masticatory function were achieved. The results of the literature review showed that patients with ectodermal dysplasia who are congenitally edentulous usually have a complex intraoral situation that makes restoration difficult, and common restorative modalities for these patients include fixed bridges, removable partial dentures, complete dentures, overdentures, and implant prostheses, which need to be selected according to the actual intraoral situation of each patient. Currently, there is no consensus on the treatment of congenitally missing teeth in patients with ectodermal dysplasia, and some scholars have suggested that fixed restorations be recommended for patients with fewer missing teeth, while the option of removable or implant-covered denture restorations should be given to patients with more missing teeth, with removeable prostheses for underage patients that are replaced with permanent fixed prostheses when the jaws have stabilized.@*Conclusion@#In patients with ectodermal dysplasia with congenital tooth loss, all factors should be taken into account, and an individualized restorative plan should be developed.

Reabilitação oral com próteses parciais removíveis após restabelecimento de dimensão vertical de oclusão e tratamento multidisciplinar: relato de caso / Oral rehabilitation with removable partial dentures after restoration of the vertical dimension of occlusion and multidisciplinary treatment: case report

As próteses parciais removíveis (PPRs) são uma alternativa de tratamento viável na prática clínica para reabilitar arcos parcialmente desdentados. Entretanto, o planejamento dessas próteses e preparo bucal prévio são frequentemente negligenciados. O presente artigo tem como objetivo relatar o caso clínico de uma reabilitação oral com PPRs superior e inferior após abordagem multidisciplinar, de modo a enfatizar as fases de um planejamento criterioso e de preparo prévio dos dentes pilares, visando o sucesso e a longevidade da reabilitação. Paciente do sexo masculino de 57 anos de idade compareceu à clínica da Faculdade de Odontologia de Bauru, Universidade de São Paulo, queixando-se da estética de seu sorriso e de algumas ausências dentárias. O indivíduo utilizava uma PPR provisória inferior insatisfatória e apresentava perda de dimensão vertical de oclusão (DVO). Após o exame clínico, radiográfico e estudo do caso em articulador semi-ajustável, realizou-se o planejamento com abordagens restauradoras, endodônticas, periodontais e protéticas. Após tratamento periodontal, foi realizada endodontia dos elementos 12, 15 e 47, confecção de núcleos e coroas nos dentes 12 e 15, restauração a nível gengival para apoio residual no dente 47, restaurações nos dentes 11, 13, 22, 24 e 44 e, por fim, a confecção das PPRs superior e inferior. A abordagem multidisciplinar utilizada neste caso clínico viabilizou o restabelecimento da DVO e possibilitou o sucesso da reabilitação protética(AU)

Removable partial dentures (RPDs) are a viable treatment alternative in clinical practice to rehabilitate partially edentulous arches. However, the planning of these dentures and prior oral preparation are often neglected. This article aims to report the clinical case of an oral rehabilitation with upper and lower RPDs after a multidisciplinary approach, to emphasize the phases of careful planning and prior preparation of the abutment teeth, aiming at the success and longevity of the rehabilitation. A 57-year-old male patient came to the clinic of the Bauru School of Dentistry, University of São Paulo, complaining about the esthetics of his smile and some missing teeth. The subject was using an unsatisfactory lower provisional prosthesis and had a loss of vertical dimension of occlusion (OVD). After the clinical and radiographic examination and the case study in a semi-adjustable articulator, planning was carried out with restorative, endodontic, periodontal and prosthetic approaches. After periodontal treatment, endodontics were performed on elements 12, 15 and 47, creation of cores and crowns on teeth 12 and 15, restoration at the gingival level for residual support on tooth 47, restorations on teeth 11, 13, 22, 24 and 44 and, finally, the making of the upper and lower PPRs. The multidisciplinary approach used in this clinical case enabled the restoration of the OVD and enabled the success of the oral rehabilitation(AU)

Uso de prótesis parcial removible con resina acrílica termoplástica: una revisión de literatura

La prótesis parcial removible (PPR) es una alternativa de tratamiento en pacientes que perdieron algunos elementos dentarios, debido al costo relativamente bajo y a la generación de una función masticatoria satisfactoria. Además, es una buena opción cuando hay pérdida de los tejidos óseos, dado que impide la instalación de implantes dentarios. La PPR convencional presenta una estructura metálica que ofrece retención y resistencia a la prótesis, convirtiéndola en poco agradable a los pacientes, por el hecho de dejar a la vista el metal en la cavidad oral. A partir de investigadores que decidieron ir más allá del simple estudio de la función y la estética de las PPR para adentrase en sus diversas formas de presentación, surgió la prótesis parcial flexible (PFlex). La PFlex es una prótesis parcial confeccionada con resina termoplástica, sin metal y con flexibilidad. Si bien, muchos profesionales la emplean como prótesis temporal, otros tantos la han usado como alternativa a la PPR convencional. Así, uno de los frecuentes interrogantes de los clínicos es si realmente es posible utilizar la PFlex como alternativa protética definitiva. Por tanto, el propósito de este trabajo fue realizar una revisión de la literatura para evaluar si el uso de prótesis parciales removibles con resina termoplástica puede ser una alternativa a las prótesis parciales convencionales, exponiendo las ventajas, desventajas, indicaciones, contraindicaciones y las propiedades del material protético.

Removable partial denture (RPP) is an alternative treatment when it comes to patients who have lost some dental elements, as they have the advantages of a relatively low cost and a satisfactory masticatory function. Furthermore, it is a good option when there is bone tissue loss, making dental implants placement unfeasible. Conventional PPR has a metallic frame that provides retention and resistance to the prosthesis, which makes it unpalatable to patients because it leaves the metal in the oral cavity evident. Many researchers, aiming to give back beyond function and aesthetics, are studying forms of presentation of PPR, thus emerging the flexible partial prosthesis (PFlex). PFlex is a partial denture made with thermoplastic, resin metal-free and with flexibility, however its use, for many professionals, is limited only as temporary prostheses, but there are some clinicians who use PFlex as an alternative to conventional PPR. Thus, one of the questions constantly asked by scientists is whether it is possible to use PFlex as a definitive prosthetic alternative. Therefore, the aim of this study was to conduct a literature review to assess whether the use of removable partial dentures with thermoplastic resin can be an alternative to conventional partial dentures, exposing the advantages, disadvantages, indications, contraindications, and the properties of the prosthetic material.

Desarrollo y aplicación de un software educativo bidimensional para el proceso de enseñanza del diseño de Prótesis Parcial Removible / Validation of a two-dimensional educational software for the learning process of the design of Removable Partial Dentures

Objetivo: El objetivo de este estudio fue desarrollar e implementar un software educativo bidimensional para el proceso de aprendizaje del diseño de Prótesis Parciales Removibles.Materiales y métodos: Se utilizó el método científico y procedimientos de evaluación educativa para abordar las necesidades de la asignatura de Prótesis Parcial Removible en la Facultad de Odontología de la UNMSM de Perú en el año 2022. Se utilizó análisis, síntesis y encuestas. Se examinó la aplicabilidad del software y el cumplimiento de los requerimientos de enseñanza y aprendizaje, no sólo en la UNMSM sino en cualquier universidad con requerimientos y características similares. Resultados: La aplicación in-terna del software arrojó un valor final del 96%, mientras que la evaluación de alumnos y docentes mostró un 90% de aceptación, al considerar que el SEDUPPR es sencillo para instalar, sencillo en su manejo y funcionamiento, y es muy útil para aprender diseño de PPR. Conclusiones: El software educativo bidimensional diseñado para el proceso de aprendizaje de Prótesis Parcial Removible es aplicable y puede ser implementado en diferentes ámbitos educativos.

Objective: The objective of this study was to develop and implement a two-dimensional educational software for the learning process of designing Removable Partial Prostheses.Materials and Methods: The scientific method and educational evaluation procedures were utilized to address the needs of the Removable Partial Prosthesis subject in the Fa-culty of Dentistry at the UNMSM in Peru in 2022. Analysis, synthesis, and surveys were used. The software's applicability and fulfillment of teaching and learning requirements were examined, not only at the UNMSM but also in any university with similar require-ments and characteristics. Results: The internal application of the software yielded a final value of 96%, while the evaluation of students and teachers showed a 90% acceptance rate, considering that SEDUPPR is simple to install, easy to use and operate, and is very useful for learn PPR design. Conclusion: The two-dimensional educational software designed for the learning process of Removable Partial Prosthesis is applicable and can be implemented in different educational settings.

Cambios en parámetros masticatorios con prótesis parcial removible para dientes posteriores perdidos / Changes in masticatory parameters with removable partial dentures for missing posterior teeth

Introducción: el reemplazo de dientes perdidos aspira a mejorar la función masticatoria. Aunque hay diferentes opciones para ello, la conveniencia de la prótesis parcial removible (PPR) es su bajo costo. Objetivo: comparar el desempeño masticatorio (DM) después de 20 ciclos masticatorios y al umbral de la deglución (UD) en adultos de 50 a 70 años con dientes posteriores perdidos (DPP), con/sin PPR; y los ciclos hasta la deglución. Material y métodos: estudio transversal en 35 adultos con dientes anteriores y PPR bien ajustadas y utilizadas para comer. El lado de prueba fue el lado con más DPP. El DM se evaluó después de 20 ciclos y al UD utilizando un alimento prueba artificial (Optosil Comfort®) con/sin la PPR en orden aleatorizado. Las partículas se tamizaron para determinar el tamaño medio de partícula (TMP) como medida del DM. Los ciclos se contaron visualmente. Estadística descriptiva y comparaciones con SPSS-v23. Resultados: hubo diferencias significativas (p ≤ 0.05) al masticar con/sin PPR. El TMP fue más pequeño (mejor DM) con la PPR después de 20 ciclos y al UD (3.9 vs 4.4 mm y 3.2 vs 4.2 mm). Los ciclos para llegar al UD disminuyeron con la PPR (40 vs 47). Conclusión: a pesar de una mejora limitada de la función masticatoria, las PPR ayudan a preparar los alimentos en partículas más pequeñas antes de deglutirlas. La mejoría en DM con PPR es de 24% al UD, realizando menos ciclos antes de deglutir sus alimentos (AU)

Introduction: replacement of missing teeth should improve masticatory function. Although there are different options removable partial dentures (RPD) are used due to their lower cost. Objective: to compare masticatory performance (MP) after 20 chewing-cycles and swallowing-threshold (ST) in 50-70 year-old adults with missing posterior teeth (MPT) with and without their cast-metal RPD; chewing cycles until swallowing were also compared. Material and methods: 35 adults participated in this cross-sectional study. Subjects with anterior teeth and welladjusted RPDs, used for eating were included. The side with more MPT was selected as the test side. MP was evaluated after 20 cycles and ST using an artificial test-food (Optosil Comfort®) with/without the RPD (subject-own-control) (randomized order). Chewed particles were sieved to determine medium-particle-size (MPS) as a measure of MP. Chewing cycles were visually counted. Descriptive statistics and comparisons were run with SPSS v23. Results: there were significant differences (p ≤ 0.05) for all parameters when chewing with/without the RPD. MPS was smaller (better MP) with the RPD (3.9 vs 4.4 mm and 3.2 vs 4.2 mm) after 20 cycles and ST respectively. Cycles required to reach ST were less when chewing with the denture (40 vs 47). Conclusion: despite a limited improvement of masticatory function RPDs help patients prepare their food into smaller particles before swallowing. Improvement in MP with RPDs for patients with MPT is 24% at ST and they perform fewer chewing cycles before swallowing food (AU)

Orthodontic aligners: between passion and science

ABSTRACT Introduction: The benefits and safety of using orthodontic aligners have been reported more by clinical experience and expert opinion than by scientific evidence. Another important aspect is that aligners are constantly evolving. It is important to obtain evidence that allows for new updates in manufacturing technology, in the development of new movement planning protocols, in the incorporation and design of attachments, and in the aid of skeletal anchorage. Methods: Evidence retrieved from six electronic databases (CINAHL, MEDLINE, EMBASE, Psych Info, the Cochrane Library and the Joanna Briggs Library) is presented by means of questions and answers. Conclusions: There is evidence that the aligners presented different levels of difficulty in performing each type of movement, with rotational and vertical movements being the most difficult to perform. Regarding perception of pain due to tooth movement, it seems to have less impact at the beginning of treatment; but dealing with more phonoarticulatory changes seems to require more treatment time in more complex cases. Aligners do not prevent the occurrence of root resorption, although the incidence and severity of resorption may be reduced, making oral hygiene easier and accepting the risk of white spots, caries and periodontal disease. Given the conflicting evidence, the release of bisphenol-A from the aligner cannot be denied. Solutions must be found to reduce the environmental impact of aligners disposal. There is an urgent need for well-designed randomized controlled trials.

RESUMO Introdução: As vantagens e desvantagens do uso de alinhadores ortodônticos têm sido reportadas com base mais na experiência clínica e opinião de experts do que em evidências científicas. Outro aspecto importante é que os alinhadores estão em processo de evolução constante. Assim, torna-se importante obter evidências recentes, que abranjam as novas atualizações na tecnologia de confecção, no desenvolvimento de novos protocolos de planejamento para as movimentações, a incorporação e desenho dos attachments e o auxílio da ancoragem esquelética. Métodos: As evidências encontradas em seis bases de dados eletrônicas (CINAHL, MEDLINE, EMBASE, Psych Info, Biblioteca Cochrane e Biblioteca Joanna Briggs) serão apresentadas por meio de perguntas e respostas. Conclusões: Há evidências de que os alinhadores apresentam diferentes níveis de dificuldade para realizar cada tipo de movimento, sendo os movimentos rotacionais e verticais os mais difíceis de serem executados. Quanto à percepção da dor causada pela movimentação dentária, parece haver menos impacto no início do tratamento, mas os alinhadores produzem mais alterações fonoarticulatórias e parecem exigir mais tempo de tratamento em casos mais complexos. Não há evidência de diferença na estabilidade pós-tratamento, e os alinhadores não impedem a ocorrência de reabsorção radicular, apesar da incidência e a gravidade da reabsorção poderem ser menores, facilitam a higiene bucal, reduzindo o risco de manchas brancas, cáries e doenças periodontais. Dada a evidência conflitante, a liberação de bisfenol-A pelo alinhador não pode ser negada. É preciso encontrar soluções que reduzam o impacto ambiental do descarte dos alinhadores. Há uma necessidade urgente de ensaios clínicos randomizados bem desenhados.

The effect of different framework's material on strain induced in distal abutment in mandibular Kennedy's class II: an in-vitro study / O efeito de diferentes materiais de estrutura na deformação induzida na distal do pilar da classe II de Kennedy mandibular: um estudo in vitro

Objective: This study aims to compare the strain induced in the supporting structures of unilateral mandibular removable partial denture frameworks retained by extra-coronal attachments fabricated with three different materials. Material and Methods: Three mandibular class II digitally designed and printed acrylic models with detachable abutments were used to fabricate three removable partial denture framework with extra coronal attachments from three different materials. A total of 33 models were prepared for strain testing (n=11). Models were divided into three groups according to framework's material: porcelain fused to cobalt chromium (PFM), polyetherketoneketone (PEKK) and polyetheretherketone (PEEK) group. Unilateral load of 60 N was applied in the three groups and strains were measured around the main abutment and saddle area using strain gauge. Results: Statistical analysis was performed using Shapiro-Wilk's test and by checking data distribution. Data were found to be non-parametric and were analysed using Kruskal-Wallis test followed by Dunn's post hoc test with Bonferroni correction. PFM group showed significantly the highest strain values around abutment, slot 1 (1mm distal to the socket of the last abutment) and slot 2 (1 cm away from slot 1) respectively (843.00±23.08, 91.00±6.52 and 1274.00±65.71) than the other tested groups (p<0.05) at same tested sites respectively followed by PEKK group (384.00±37.48, 81.00±2.24 and 135.00±0.00) and PEEK group (29.00±4.18, 63.00±4.47 and 52.00±5.70). Conclusions: PEEK and PEKK for partial denture framework with extra coronal attachments are adequate alternative to PFM due to their good mechanical response applying less strain on supportive structures in free-end cases. PEEK induces lower strain magnitude on the supporting structures when compared to PEKK. (AU)

Objetivo: Este estudo tem como objetivo comparar a tensão induzida nas estruturas de suporte de estruturas de próteses parciais removíveis mandibulares unilateraisretidas por encaixes extracoronários fabricados com três materiais diferentes. Material e Métodos: Três modelos mandibulares de classe II digitalmente projetados e impressos em acrílico com pilares destacáveis foram usados para fabricar três estruturas de próteses parciais removíveis com encaixes extracoronários de três materiais diferentes. Um total de 33 modelos foram preparados para testes de deformação (n=11). Os modelos foram divididos em três grupos de acordo com o material da estrutura: porcelana fundida com cobalto-cromo (PFM), poliétercetonacetona (PEKK) e polieteretercetona (PEEK). Carga unilateral de 60 N foi aplicada nos três grupos e as deformações foram medidas em torno do pilar principal e área de sela usando medido de tensão. Resultados: A análise estatística foi realizada por meio do teste de Shapiro-Wilk e com a verificação da distribuição dos dados. Os dados mostraram-se não paramétricos e foram analisados pelo teste de Kruskal-Wallis seguido pelo de Dunn com correção de Bonferroni. O grupo PFM mostrou significativamente os maiores valores de tensão ao redor do pilar, slot 1 (1mm distal do último pilar) e slot 2 (1 cm de distância do slot 1) respectivamente (843,00±23,08, 91,00±6,52 e 1274,00±65,71) do que os outros grupos testados (p<0,05) nos mesmos locais testados, respectivamente, seguido pelo grupo PEKK (384,00±37,48, 81,00±2,24 e 135,00±0,00) e grupo PEEK (29,00±4,18, 63,00±4,47 e 52,00±5,70). Conclusão: PEEK e PEKK para estrutura de prótese parcial com encaixes extracoronários são alternativas adequadas ao PFM devido à sua boa resposta mecânica aplicando menos tensão nas estruturas de suporte em casos de extremidade livre. O PEEK induz menor magnitude de deformação nas estruturas de suporte quando comparado ao PEKK (AU)

Audit to assess the quality of 916 prosthetic prescriptions of removable partial dentures / 华西口腔医学杂志

OBJECTIVES@#The objectives of this study were to assess the quality of prosthetic prescriptions of removable partial dentures (RPDs) and to analyze the current situation of the communication and information delivery between clinicians and technicians.@*METHODS@#All RPD prosthetic prescriptions received by a major dental laboratory in 4 weeks were involved in a quality audit, and the prescriptions were divided into three groups in accordance with the grades of clients. The filling of prosthetic prescriptions was recorded. The items in the prescriptions for audit included the general information of the patient, the general information of the clinician, the design diagram information, other detailed information, and the return date. The prescriptions were categorized into four levels on the basis of their quality by two quality inspectors who have been working for more than 10 years.@*RESULTS@#A total of 916 prescriptions were collected and assessed. The names in the general information of the patient and the clinician were filled out best, both at the rate of 97.6% (n=894). The return date was filled out worst, only at the rate of 6.4% (n=59). Of those prescriptions, 86.8% (n=795) exhibited inadequate design diagram information. The results of the quality assessment demonstrated that 74.2% of prescriptions were assessed as noncompliant ones and failed to meet the acceptable clinical quality standard.@*CONCLUSIONS@#At present, the overall quality of RPD prosthetic prescriptions is poor. The responsibilities of clinicians and technicians are unclear, and the communication between them is not ideal.

Bibliometric Analysis of Removable Partial Denture-related Research in Dentistry

@#The objective of this study was to characterise articles published in removable partial denture (RPD) research from 1948 to 2022 to identify the most influential journals, publications, authors, and core research areas using bibliometric analysis. The Scopus database was used to retrieve publications with titles containing the truncated search term (“removable partial denture*” OR “removable prostho*”). Data analysis and visualisation were done using Microsoft Excel, Biblioshiny software and VOSviewer. A total of 2,484 articles were analyses from 1948 till 2022, representing an annual growth rate of 4.9%. The Journal of Prosthodontic Research demonstrated the highest average normal citation rate, with productive authors with highest citations being from Japan. From 1948 to 1999, most in-vitro and clinical research focused on the basic concept of RPD using cobalt-chromium as a framework before shifting to titanium in 2000. RPD research after 2012 focuses on new technology and non-metalbased frameworks as an alternative to metal-based frameworks. Wakabayashi and Fueki were the most prominent researchers, according to a three-field plot analysis, with the Journal of Prosthetic Dentistry, Journal of Oral Rehabilitation, and Journal of Prosthodontic Research among the authors’ preferred journals. “CAD/CAM” and “3D printing” were identified as emerging themes in year 2020 to 2022, while “selective laser melting” was the trending keyword in 2017 to 2019. Research on “oral health and quality of life” has been identified as core research area in RPD-related research. RPD research on digital dentistry and new framework materials is anticipated to increase in the future with the incorporation of research on quality of life.

X-linked hypohidrotic ectodermal dysplasia management with removable prosthesis in a pediatric patient: case report / Manejo de displasia ectodérmica hipohidrótica ligada al cromosoma X con prótesis removible en un paciente pediátrico: reporte de caso

Introduction: Ectodermal dysplasia is a rare genetic disorder that affects structures derived from ectoderm such as teeth, hair, nails, and sweat glands. Oligodontia is a common finding that affects the chewing, smiling and self- esteem of these pediatric patients. Case Report: We present a case report of a 7-years-old pediatric patient who consulted with his mother, showing the same condition. The intervention consisted of a removable prosthesis with satisfactory results. Conclusion: The X-linked hypohidrotic ectodermal dysplasia represents a challenge for a pediatric dentist who offers rehabilitation to the patient according to craniofacial development, age, socioeconomic status, and the number of missing teeth.

Introducción: La oligodoncia es un hallazgo común que afecta la masticación, la sonrisa y la autoestima de estos pacientes pediátricos. Case Report: Presentamos un reporte de caso de un paciente pediátrico de 7 años que consultó con su madre presentando la misma condición. La intervención consistió en una prótesis de remoción con resultados satisfactorios. Conclusión: La displasia ectodérmica hipohidrótica ligada al cromosoma X representa un desafío para un odontopediatra que ofrece rehabilitación al paciente de acuerdo con el desarrollo craneofacial, la edad, el nivel socioeconómico y el número de dientes faltantes.

Reabilitação oral utilizando prótese parcial removível associada a implantes osseointegrados: relato de caso / Oral rehabilitation using removable partial prosthesis associated with osseointegrated implants: case report

Introdução: As próteses parciais removíveis são alternativas amplamente utilizadas na reabilitação oral de pacientes parcialmente desdentados. Na atualidade os implantes dentais têm sido indicados para tratamento de pacientes edêntulos em associação com próteses parciais removíveis convencionais. Objetivo: Relatar um caso clínico utilizando uma prótese parcial removível convencional associada a implantes osseointegrados em paciente portador de Classe I de Kennedy. Relato de Caso: Paciente N.A.A.S., sexo feminino, 65 anos, procurou atendimento clínico no Instituto de Estudos da Saúde (IES) para reabilitação protética das arcadas dentais superior e inferior. A sua queixa principal era "dificuldade de mastigação". A paciente apresentava prótese total removível insatisfatória na maxila e não utilizava nenhum tipo de prótese dentária na mandíbula, que se apresentava parcialmente edêntula. O tratamento realizado foi a confecção de uma prótese total na arcada superior. Na arcada inferior foram inseridos dois implantes de hexágono externo nas regiões correspondentes às áreas dos dentes 34 e 44, após quatro meses a prótese parcial removível convencional foi confeccionada e incorporada aos implantes osseointegrados utilizando o sistema de retenção do tipo attachments Equator. Conclusão: Os resultados revelaram que a técnica de associação da prótese parcial removível convencional aos implantes osseointegrados demonstrou ser uma opção viável de tratamento com capacidade de devolver a função, a estética e manter a integridade dos dentes e tecidos periodontais(AU)

Introduction: Removable partial dentures are alternatives widely used in the oral rehabilitation of partially edentulous patients. Currently, dental implants have been indicated for the treatment of edentulous patients in association with conventional removable partial dentures. Objective: To report a clinical case using a conventional removable partial denture associated with osseointegrated implants in a patient with Kennedy Class I. Case Report: Patient N.A.A.S., female, 65 years old, sought clinical care at the Institute of Health Studies (HEI) for prosthetic rehabilitation of the upper and lower dental arches. His main complaint was "chewing difficulty". The patient had unsatisfactory removable total prosthesis in the maxilla and did not use any type of dental prosthesis in the mandible, which was partially edentulous. The treatment performed was the manufacture of a total prosthesis in the upper arch. In the lower arch, two external hexagon implants were inserted in the regions corresponding to the tooth areas 34 and 44, after four months the conventional removable partial denture was made and incorporated into the osseointegrated implants using the equator attachments retention system. Conclusion: The results revealed that the technique of associating conventional removable partial dentures with osseointegrated implants proved to be a viable treatment option with the ability to restore function, aesthetics and maintain the integrity of teeth and periodontal tissues(AU)

Post-Expansion and End of Treatment Outcomes of Semi-Rapid Maxillary Expansion with a Modified Removable Appliance

Context: Maxillary expansion is the mainstay therapy for maxillary transverse deficiency. There has been a constant search for the most effective yet biologically friendly method of maxillary expansion, alternatives being, slow, rapid and semi rapid. Aims: The purpose of this study was to explore the outcome of palatal expansion achieved using a removable plate and low continuous forces brought about by a semi rapid screw activation protocol. Settings and Design: Retrospective study. Methods and Material: Plaster models of 56 consecutive patients treated for maxillary expansion were obtained pre?treatment (T0), post?expansion (T1), and post fixed appliance treatment (T2). The radiographic images of the models were traced using Image J software. Linear and angular measurements were evaluated to measure transverse change. Statistical Analysis Used: Interclass Correlation Coefficient [ICC] and Dahlberg’s formula were used for reliability test. The differences in the mean values between the three duration groups [T0, T1 and T2] were analysed using Analysis of Variance (ANOVA). For multiple comparisons, a post hoc Tukey honestly significant difference (HSD) test was performed. Results: Significant increase in inter?molar, alveolar and palatal linear widths were observed from T0 to T1 with significant relapses from T1 to T2, with an overall net gain remaining at T2. Similarly, significant increases in all angular measurements were observed from T0 to T1 with significant relapses from T1 to T2 and an overall insignificant change at T2 as compared to T0. Conclusion: The appliance and protocol were effective in producing transverse expansion with minimal molar and alveolar tipping.

Ectodermal dysplasia: A case report

Ectodermal dysplasia (ED) is a rare group of inherited disorders with defects in the development of one or more tissues derived from primary embryonic ectodermal derivatives. The inclusion of ED does not include all ectodermal derivatives and is manifested with a defect in skin, hair, teeth, and eccrine glands. Dry skin, frontal bossing, scanty eyebrows, and hair follicles are common features seen in these patients. The patient may suffer from high fever due to the absence of eccrine glands. Intraoral findings include a partial or complete absence of teeth with generalized spacing. It can be inherited or caused by a genetic mutation, and it can also happen without a family history. This case report presents a 12-year-old female child with hypohidrotic ED involving a multidisciplinary approach in ED that was beneficial both physiologically and psychologically is discussed in this case report.

Consensos referidos a conceptos rehabilitadores en la enseñanza de la odontología. Parte I: conceptos generales y diseño de la prótesis parcial removible / Consensus referring rehabilitative concepts in the teaching of dentistry. Part I: general concepts and design of removable partial prosthesis

En este artículo se desarrolla el consenso alcanzado entre profesores, referido a los conceptos generales, componentes y la secuencia del diseño de la prótesis parcial removible, durante la formación del odontó-logo en el ámbito de la Facultad de Odontología de la Universidad de Buenos Aires (AU)

This article develops the consensus between professors on the general concepts, components, and the sequence of the design of the partial removable prosthesis during the training of the dentist in the field of the Faculty of Dentistry of the University of Buenos Aires (AU)

Diagnóstico e tratamento precoce da má oclusão de Classe III com Aparelho Disjuntor Hyrax e Máscara Facial de Petit com avaliação do tempo de uso com micro-sensor: relato de caso clínico / Early diagnosis and treatment of Class III occlusion with Hyrax Isolating Appliance and Petit Face Mask with evaluation of the time of use with micro-sensor: a clinical case report

O sucesso do tratamento precoce da classe III depende de um bom diagnóstico e da cooperação do paciente na utilização do aparelho extrabucal. Neste trabalho, por meio de um chip (Theramon) instalado na Máscara Facial de Petit da paciente, foi possível monitorar a quantidade de horas que a paciente utilizou o aparelho por dia, durante um período de quatro meses. Paciente do sexo feminino, 7 anos e 11 meses de idade portadora da má oclusão de classe III, utilizou o aparelho de disjunção da maxila (Hyrax) modificado, seguido da Máscara Facial de Petit com chip (Theramon) instalado. A média de uso foi maior do que 11 horas de uso diário. O uso deste dispositivo auxilia no monitoramento do tempo de uso do aparelho, cujo sucesso do tratamento depende da utilização deste pelo paciente(AU)

The success of early treatment of class III depends on a good diagnosis and the cooperation of the patient in the use of the extra oral appliance. In this study, the patient was able to monitor the number of hours the patient used the device per day during a period of four months using a Theramon chip installed in the Patient's Facial Mask. A 7-year, 11-month-old male with Class III malocclusion used the modified maxillary disjunction (Hyrax), followed by the Petit Facial Mask with a Theramon chip installed. The average use was greater than 11 hours of daily use. The use of this device assists in the monitoring of the time of use of the device, whose success of the treatment depends on the use of this by the patient(AU)

Application prospect of polyetheretherketone in postcore crown restorations / 口腔疾病防治

@#Polyetheretherketone (PEEK) is known as a high-grade engineering plastic with good mechanical properties, chemical stability and biocompatibility. Currently, PEEK materials have been widely used in prosthodontics, such as complete dentures and removable partial dentures. The relevant research shows that PEEK posts are superior to glass fiber posts, which have high tensile bond strength and bending strength. At present, few case reports of PEEK postcores have been published, and clinical case reports suggest that PEEK postcores have good oral prosthetic aesthetics and are ideal and reliable postcore crown materials. However, the preparation and surface treatment methods of PEEK require further refinement. A review of the related properties of PEEK and the prospects of its application in the field of postcore crown restoration will be presented in this paper.

Application of a metal occlusal surface and split framework in the treatment of a patient with mandibular distal extension absence and insufficient occlusogingival distance / 口腔疾病防治

Objective@# To investigate the effect of a metal occlusal surface and stress interruption design on minimally invasive prosthodontics for patients with distal extension absence and insufficient occlusal gingival distance.@*Methods @# We retrospectively studied the case of minimally invasive prosthodontic (Vitallium 2000) combined with a metal occlusal surface for distal extension absence in a patient with insufficient occlusal gingival distance; the stress breaking design and pressure impression technology are examined, and relevant articles are reviewd. @*Results@#The design effectively solves the problems of insufficient occlusal gingival distance, large occlusal force and easy denture fracture. Reviewing the relevant literature, stress interruption design can effectively protect abutment teeth, but the behavior of stress interruption design and stress conduction phenomena in the mouths of patients has not been reported. The T-scan test results of this study showed that before and after wearing the denture, the occlusal force distribution ratio of the patient changed from 77.5% on the left and 22.5% on the right to 61.3% on the left and 38.7% on the right. The occlusal force distribution ratio of the right dentition to the total occlusal force increased by 16.2%, and the occlusal force became better distributed. Further analysis showed that the occlusal forces on the left and right sides were nearly the same in the initial occlusion stage. As the occlusal force was further increased, the proportion of the occlusal force on the right side decreased in the middle of the occlusion stage and further decreased in the final occlusion stage until it reached a dynamic balance. The above T-scan test and literature review results suggest that this dynamic balance phenomenon of bite force is related to the stress interruption design and the stress conduction effect of the split framework.@* Conclusion @#The composite of stress interruption design and metal occlusal surface allows for minimally invasive prosthodontics for the treatment of distal extension absence in patients with insufficient occlusal gingival distance.