Periodontal indexes of two types of 3 x 3 retainers: 0.032-in SS V-loop versus 0.0215-in SS coaxial - a randomized crossover trial

ABSTRACT Objective: This randomized crossover trial evaluated periodontal indexes of two types of 3 x 3 retainers (a modified 0.032-in SS V-loop retainer and a conventional 0.0215-in SS coaxial wire retainer) after bonded for six months. Also, bonded failure rate, and a questionnaire about comfort, ease of cleaning and overall preference were recorded. Material and Methods: 15 patients were enrolled in this study who used both retainers for six months each, having a 15-day wash-out interval between each bonded retainer usage. The following periodontal index were recorded: Plaque Index (PI), Calculus Index (CI) and Gingival Index (GI). Patients answered a questionnaire to assess comfort, ease of cleaning and overall retainer-type preference. Rate of bonding failure was also evaluated. Results: V-Loop retainer showed higher PI (P<0.05) as compared to conventional 0.0215-in coaxial wire retainer. However, CI and GI presented no statistically significant differences between both types of retainers. The conventional 0.0215-in coaxial wire retainer was chosen as the most comfortable (p<0.05), although no statistically significant differences were found for all other questionnaire answers. Bonding failure events were more observed in the 3x3 V-Loop retainer (p<0.002), as compared to the conventional 0.0215-in coaxial retainer. Conclusion: V-Loop retainer showed higher PI (p<0.05), higher bonding failure rate and less comfortable, as compared to conventional 0.0215-in coaxial wire.

RESUMO Objetivo: Este estudo cruzado e randomizado avaliou os índices periodontais de dois tipos de contenções 3x3 (uma contenção aço V-Loop de 0,032" modificada e uma contenção convencional de fio coaxial aço de 0,0215") após colagem, por seis meses. Além disso, foram registradas a taxa de falha na colagem e um questionário sobre conforto, facilidade de limpeza e preferência geral. Material e Métodos: Foram incluídos nesse estudo 15 pacientes que usaram ambas as contenções por seis meses cada, com intervalo de quinze dias entre cada contenção fixa. Foram registrados os seguintes índices periodontais: Índice de Placa (IP), Índice de Cálculo (IC) e Índice Gengival (IG). Os pacientes responderam a um questionário para avaliar o conforto, a facilidade de limpeza e a preferência geral pelo tipo de contenção. A taxa de falha de colagem também foi avaliada. Resultados: A contenção V-Loop apresentou maior IP (p<0,05) em comparação ao fio coaxial convencional. Entretanto, IC e IG não apresentaram diferenças estatisticamente significativas entre as contenções testadas. A contenção convencional de fio coaxial 0,0215" foi escolhida como a mais confortável (p<0,05), embora não tenham sido encontradas diferenças estatisticamente significativas para todas as outras respostas do questionário. Eventos de falha de colagem foram mais observados na contenção V-Loop 3 x 3 (p<0,002) em comparação com a contenção coaxial convencional de 0,0215". Conclusão: A contenção V-Loop apresentou maior IP (p<0,05), maior taxa de falha de colagem e foi menos confortável em comparação ao fio coaxial convencional 0,0215".

Clinical comparisons of different fixed orthodontic retainers

ABSTRACT Objective: The aim of this prospective clinical study was to compare the clinical outcomes of three different fixed lingual retainers, in terms of effects on periodontal health and success rate. Methods: Forty five patients aged 13 to 25 years were randomly assigned into three groups, using bonded upper and lower lingual retainers. The study groups were as follows: Group 1- Bond-A-Braid®, Group 2- everStick® ORTHO, Group 3- Super-Splint. The follow-up appointments were performed two weeks (Baseline=T0), one month (T1), three months (T2), and six months (T3) after the application of retainers. Plaque Index (PI), Gingival Index (GI), Probing Depth (PD), Bleeding in Probing (BOP) and Retainer Failure were assessed at each appointment. Results: The everStick Ortho group showed significantly lower PI values on the upper-lower lingual side after three (p=0.008) and six (p=0.001) months. The everStick Ortho group had significantly lower upper lingual (GI) levels after six months, and lower lingual side levels after one month. The Super-Splint group showed significantly lower PD values on the upper lingual side after six months. The everStick Ortho group presented significantly lower BOP levels after six months on the upper lingual side. No significant differences between the groups (p>0.05) in terms of retainer failure were found. Conclusions: The everStick Ortho group presented better results in terms of periodontal health. The failure rates of the retainers were similar.

RESUMO Objetivo: O objetivo do presente estudo clínico prospectivo foi comparar a taxa de sucesso de três tipos de contenção lingual fixa e seus efeitos clínicos sobre a saúde periodontal. Métodos: Quarenta e cinco pacientes, com idades entre 13 e 25 anos, usando contenções fixas coladas nas arcadas superior e inferior foram agrupados, aleatoriamente, nos três seguintes grupos: Grupo 1 - Bond-A-Braid®; Grupo 2 - everStick® ORTHO; e Grupo 3 - Super-Splint. As consultas de acompanhamento foram feitas após duas semanas (inicial = T0), um mês (T1), três meses (T2) e seis meses (T3) da instalação das contenções. Em todas as consultas, foram avaliados o Índice de Placa (IP), Índice Gengival (IG), Profundidade de Sondagem (PS), Sangramento à sondagem (SAS) e Falha da Contenção. Resultados: O grupo everStick Ortho mostrou valores de IP significativamente menores nas faces linguais dos dentes superiores e inferiores após três (p=0,008) e seis (p=0,001) meses. O grupo everStick Ortho também apresentou níveis significativamente menores de IG na face lingual dos dentes superiores após seis meses, e face lingual dos dentes inferiores após um mês. O grupo Super-Splint mostrou valores significativamente menores de PS na face lingual dos dentes superiores após seis meses. O grupo everStick Ortho apresentou níveis significativamente menores de SAS na face lingual dos dentes superiores após seis meses. Quanto à falha na contenção, não houve diferença significativa (p>0,05) entre os grupos. Conclusões: O grupo everStick Ortho apresentou os melhores resultados em termos de saúde periodontal. As taxas de falha das contenções foram semelhantes.

Influence of customization and light-curing device on the bond strength of glass fiber posts - in vitro study / Influência da reanatomização e do aparelho fotopolimerizador na resistência de união de pinos de fibra de vidro - estudo in vitro

Introduction: Endodontically treated teeth are usually affected by extensive structure loss requiring the use of intraradicular posts to provide retention and restoration. Objective: An in vitro assessment was performed on the bonding of glass fiber posts to the root dentin. Material and method: Ninety (n = 10) single bovine roots were used in a 3 x 3 x 3 factorial study with subdivided plots: post customization varying the presence and type of resin (without customization, conventional resin, and Bulk Fill resin), light-curing device (Valo, Radii-Cal, Rainbow), and root third (cervical, middle, and apical). Result: For the customization factor, Tukey's test (5%) showed the superiority of the Bulk Fill (8.16 MPa) and Z350 (7.40 MPa) groups compared to the control group (4.92 MPa), without differing from each other. All light-curing devices differed, showing the superiority of Valo (9.36 MPa), Radii (6.96 MPa) as an intermediate, and the inferiority of Rainbow (4.17 MPa). The cervical root third (7.81 MPa) was superior, the apical third was inferior (5.80 MPa), and the middle third (6.88 MPa) was an intermediate without differing from the others. Conclusion: The customization of glass fiber posts increases the bond strength to the root dentin, regardless of the resin used. There was a compromise in the apical third and when using light-curing devices with lower light intensity.

Introdução: Dentes com extensa perda de estrutura podem comprometer a retenção das restaurações ao remanescente dental, onde pinos intraradiculares são indicados. Objetivo: Avaliou-se in vitro a união de pinos de fibra de vidro à dentina radicular em função de diferentes modos de reanatomização, fotopolimerizadores e regionalização radicular. Material e método: Noventa (n=10) raízes bovinas uniradiculares foram usadas num estudo fatorial 3 x 3 x 3 com parcelas subdivididas: Reanatomização do pino, variando a presença e tipo de resina (Sem reanatomização, Resina Convencional e Resina Bulkfill); Fotopolimerizador (Valo, Radii-cal, Rainbow); e Terço radicular (cervical, médio e apical). Resultado: O teste de Tukey (5%) evidenciou para o Fator Reanatomização superioridade dos grupos BulkFill (8.16MPa) e Z350 (7.40MPa) ao grupo Controle (4.92MPa), sem diferirem entre si. Todos os fotopolimerizadores diferiram entre si, com superioridade de Valo (9.36MPa), Radii (6.96MPa) intermediário, e inferioridade de Raiwbow (4.17MPa). O terço radicular cervical (7.81MPa) foi superior e o apical inferior (5.80MPa), com o terço médio (6.88MPa) intermediário e sem diferir dos demais. Conclusão: Conclui-se que a reanatomização de pinos de fibra de vidro aumenta a resistência de união à dentina radicular, independentemente da resina utilizada, havendo prejuízo no terço apical e quando são empregados fotopolimerizadores com menor intensidade luminosa.

Influencing factors of functional orthopedic appliances on skeletal class Ⅱ malocclusion in adolescents / 口腔疾病防治

@#Functional orthodontics is one of the most important methods in the treatment of skeletal class II malocclusion in adolescents. A deep understanding of the many factors affecting the effect of functional orthopedics can improve the efficiency of correction and achieve good results. In this paper, from the two aspects of patients and appliances, we analyzed the factors that affect the curative effect of class II malocclusion functional orthopedics and deeply analyzed the therapeutic mechanism of functional appliances to guide clinical treatment. The results of the literature review show that the peak period of growth and development is the best period for the treatment of skeletal Class II malocclusion. For patients with a vertical growth type, it is recommended to use a high head cap traction appliance to prevent the lower jaw from rotating backward and downward, and functional appliances such as titanium plates or implant nail-assisted anchorage can effectively reduce the lip inclination of the lower anterior teeth. In addition, compared with the traditional functional appliance, digital and personalized transparent braces are not only more aesthetically pleasing, comfortable and beneficial to periodontal health but also have many orthopedic appliances advantages, such as two-stage fusion, better incisor torque and vertical control of the posterior teeth, and can solve the problems of anterior interference and lateral deficiency while leading. With the development of digital orthodontics, transparent appliances have become an important developmental direction for functional appliances, but there are few related studies, and more clinical studies are needed to confirm their efficacy.

Mechanical strength and inhibition of plaque biofilm activity of a novel antibacterial Hawley retainer / 口腔疾病防治

Objectives @#The purposes of this study were to evaluate the long-term mechanical property, bacteria-killing ability, protein resistance and cytotoxicity of a novel antibacterial methyl methacrylate (MMA) resin. @*Methods @#The 2-methacryloyloxyethyl phosphorylcholine (MPC) has been added into the MMA used for making Hawley orthodontic retener according to the mass percentage 0% (control group), 1.5%, 2.25%, 3%, 4.5% and 6%. Specimens from the control group and MPC group were water-aged for 1 d, 90 d and 180 d, and then the universal material testing machine was used to investigate the long-term mechanical properties of the modified MMA specimens in the oral environment. The biofilm metabolic activity, colony-forming unit (CFU) and live/dead staining assay of the biofilms in the control group and MPC group in the oral environment were tested using the dental plaque biofilm model. The micro-bicinchoninic acid (BCA) method was used to determine the amount of protein adsorbed on the specimens. The MTT method was used to evaluate the cytotoxicity of the control group and MPC group.@*Results @#In the simulated oral environment, the addition of 0% to 3% MPC had no significant effect on the mechanical properties of the MMA specimen (P > 0.05). The control group and the modified MMA specimens with 3%MPC were statistically significant in time and the interaction effects between the two groups (P < 0.05). With increasing intervention time, the mechanical strength of both groups decreased, and the effect of time varied with grouping. The protein adsorption on the surface of the modified MMA material after adding 3% MPC decreased by approximately 80%, the metabolic activity of the biofilm decreased by approximately 50%, and biofilm CFU counts decreased by approximately 70% (P < 0.05) compared with the control. There was no statistically significant difference in time or interaction effects between the two groups. The amount of live green bacteria in the 3% MPC group decreased significantly after 1, 90, and 180 d of water aging. There was no significant difference in cytotoxicity between the control group and the MPC group (P > 0.05). @*Conclusions @#The addition of MPC into the MMA resin did not compromise the mechanical properties of the resin and exhibited long-lasting antibacterial and protein-repellent effects.

Application of single-retainer all-ceramic resin-bonded fixed partial denture in the maintenance of missing incisor gap after orthodontic treatment in adolescents: a case report / 华西口腔医学杂志

This article reports a case of an orthodontic adolescent patient without a right inferior incisor. The right lower canine was used as the abutment. The single-retainer all-ceramic resin-bonded fixed partial denture was used to restore the complete dentition. Thus, the missing space was filled, and the function and aesthetics were restored.

Effect of occlusal thickness design on the fracture resistance of endocrowns restored with lithium disilicate ceramic and zirconia / 华西口腔医学杂志

OBJECTIVE@#This study aimed to investigate the effect of occlusal thickness design on fracture resistance of endocrowns restored with lithium disilicate ceramic and zirconia.@*METHODS@#A total of 24 artificial first mandibular molars were randomly divided into four groups with six teeth in each group as follows: group lithium disilicate ceramic-2 mm (lithium disilicate ceramic, with an occlusal thickness of 2 mm and a retainer length of 4 mm); group lithium disilicate ceramic-4 mm (lithium disilicate ceramic, with an occlusal thickness of 4 mm and a retainer length of 2 mm); group zirconia-2 mm (zirconia, with an occlusal thickness of 2 mm and a retainer length of 4 mm); and group zirconia-4 mm (zirconia, with an occlusal thickness of 4 mm and a retainer length of 2 mm). After adhesive cementation (RelyX Ultimate Clicker), all specimens were subjected to thermocycling (10 000 cycles). The specimens were subjected to fracture resistance testing at a 135° angle to the teeth at a crosshead speed of 0.5 mm·min⁻¹ in a universal testing machine. Data were analyzed with ANOVA and Tukey's HSD test by SPSS 15.0. The failure modes were classified.@*RESULTS@#The fracture resistances of groups lithium disilicate ceramic-
2 mm, lithium disilicate ceramic-4 mm, zirconia-2 mm, and zirconia-4 mm were (890.54±83.41), (2 320.87±728.57), 
(2 258.05±557.66), and (3 847.70±495.99) N respectively. Group zirconia-4 mm had the highest fracture resistance, whereas group lithium disilicate ceramic-2 mm had the lowest.@*CONCLUSIONS@#The fracture resistance of molar endocrown with zirconia is higher than that with lithium disilicate ceramic. Increasing the occlusal thickness can improve the fracture resistance but increase the risk of fracture of abutment.

Análise da performance mecânico-estrutural e resistência de união de diferentes técnicas de utilização de pinos de fibra de vidro / Analysis of the mechanical-structural performance and fatigue resistance of different techniques of fiberglass post

O objetivo deste trabalho foi avaliar "in vitro" e "in silico" a integridade estrutural da interface de cimentação, o comportamento biomecânico, e a resistência de união da interface dentina/cimento de diferentes técnicas de cimentação de pinos de fibra de vidro (PFV) em canais amplos. Para tanto, foram utilizados 33 incisivos bovinos. Após o tratamento endodôntico, os espécimes foram divididos aleatoriamente em três grupos (n=11): PCN- Pino convencional cimentado em dente com conduto normal; PCA- Pino convencional cimentado em dente com conduto amplo; PAA- Pino anatômico cimentado em dente com conduto amplo. Em seguida, foram executados os preparos intrarradiculares de acordo com cada grupo com brocas pré-estabelecidas, tratamento de superfície dos PFV (WhitePost nº3 DC, FGM) e cimentação dos mesmos com o cimento resinoso autoadesivo (Rely X U200, 3M ESPE). Então, 6 espécimes de cada grupo foram submetidos ao escaneamento em um microtomógrafo de alta resolução (SkyScan 1272) para avaliação da integridade, volume e presença de bolhas na interface de cimentação. Posteriormente, com base nos dados do µCT e imagens de microscopia (n=1), dois modelos tridimensionais de cada grupo foram confeccionados para a análise de elementos finitos, sendo que o primeiro foi considerado ideal (G1, G3 e G5), sem defeitos na interface, e o segundo continha as condições encontradas pela análise de µCT(G2, G4 e G6). Após o envelhecimento em estufa por 7 meses, todos os espécimes foram submetidos ao teste de resistência de união (n=10). Os dados foram submetidos à ANOVA com medidas repetidas e pós-teste de Tukey (p<0,05). O grupo PCA registrou os maiores valores médios de concentração de bolhas e fendas em relação aos grupos PCN e PAA (p< 0,05). Observou-se que a quantidade de fendas decresceu no terço apical para todos os grupos, especialmente para o grupo PAA, que registrou os menores valores médios, sendo localizadas predominantemente na face lingual entre o pino e a camada de cimento para os grupos PCN e PAA. No grupo PCA a maioria das fendas se localizaram na face vestibular entre a camada de cimento e a dentina intrarradicular. Na análise de resistência de união verificou-se diferença estatística entre os terços cervical e médio com terço apical do PCA (p< 0,05). Na comparação entre os grupos, observou-se diferença estatística na resistência de união nos PCA e PAA no terço cervical (p< 0,05), ambos sendo estatisticamente semelhantes com o PCN. Na análise "in silico" os níveis de tensão foram semelhantes na maioria das estruturas, sendo os picos de tensão observados na região cervical na face lingual. Concluiu-se que a presença de defeitos estruturais na camada da interface pode influenciar a resistência de união e o comportamento biomêcanico das diferentes técnicas de cimentação de pinos de fibra de vidro, sendo que a customização de pino de fibra de vidro com resina composta para cimentação em canais amplos proporcionou melhor desempenho de resistência de união e distribuição dos níveis de tensão na interface(AU)

The objective of this study was to evaluate "in vitro" and "in silico" the structural integrity of the cementation interface, the biomechanical behavior and the bond strength of different fiberglass post cementation techniques in flared root canal. To this end, 33 bovine incisors were used. After the endodontic treatment, the specimens were randomly divided into three groups (n = 11): PCN - conventional post cemented in tooth with normal canal lumen; PCA- Conventional fiberglass post cemented in flared root canal; PAA- Fiberglass post relined with composite resin and cemented in flared root canal; Then, the intra-radicular preparations were performed according to each group with pre-established drills, surface treatment of PFV (WhitePost Nº. 3DC, FGM) and cementation with self-adhesive resin cement (Rely X U200, 3M ESPE). Then, 6 specimens from each group were submitted to scanning in a high resolution microtomograph (SkyScan 1272) to evaluate the integrity, volume and presence of bubbles at the cementation interface. Then, based on the µCT data and the microscopic images (n = 1), two three-dimensional models of each group were made to analyze finite elements, the first one being considered ideal (G1, G3 and G5), without interface defects and the second contained the conditions found by µCT analysis (G2, G4 and G6). After being stored for 7 months, all specimens were submitted to the pushout bond strength test (n = 10). Data were submitted to ANOVA with repeated measures and Tukey post-test (p <0.05). The PCA group recorded the highest mean values of bubble and gap concentration in relation to PCN and PAA groups (p <0.05). It is observed that the number of gaps decreased in the apical third for all groups, especially for the PAA group that registered the lowest mean values, being located predominantly in the lingual face between the post and the cement layer for the PCN and PAA groups. In the PCA group, most of the gaps were located on the vestibular face between the cement layer and the intraradicular dentin. In the analysis of pushout bond strength, it was verified that statistical difference occurred between the cervical and middle thirds with apical third of the PCA (p <0.05). In the comparison between the groups, a statistical difference was observed in the bond strength in the PCA and PAA in the cervical third (p <0.05), both of which were statistically similar with the PCN. In the "in silico" analysis, the tension levels were similar in most structures, localized in the cervical region on the lingual surface. It was concluded that the presence of structural defects in the interface layer may influence the bond strength and the biomechanical behavior of the different fiberglass post cementation techniques, whereby the customization of fiberglass post with composite resin for cementation in flared root canals provided excellent bond strength performance and biomechanical behavior(AU)

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.

Influence of the amount of tooth surface preparation on the shear bond strength of zirconia cantilever single-retainer resin-bonded fixed partial denture

PURPOSE: Conventional resin-bonded fixed partial dentures (RBFPDs) are usually made with a two-retainer design. Unlike conventional RBFPDs, cantilever resin-bonded fixed partial dentures (Cantilever RBFPDs) are, for their part, made with a single-retainer design. The aim of this study was to compare the effect of tooth surface preparation on the bond strength of zirconia cantilever single-retainer RBFPDs. The objective is to evaluate the shear bond strength of these single-retainer RBFPDs bonded on 3 different amount of tooth surface preparation. MATERIALS AND METHODS: Thirty extracted bovine incisors were categorized to 3 groups (n=10), with different amounts of tooth surface preparations. Teeth were restored with single-retainer RBFPDs with different retainer surfaces: large retainer of 32 mm²; medium retainer of 22 mm²; no retainer and only a proximal connecting box of 12 mm². All RBFPDs were made of zirconia and were bonded using an adhesive system without adhesive capacity. Shear forces were applied to these restorations until debonding. RESULTS: Mean shear bond strength values for the groups I, II, and II were 2.39±0.53 MPa, 3.13±0.69 MPa, and 5.40±0.96 MPa, respectively. Statistical analyses were performed using a one-way ANOVA test with Bonferroni post-hoc test, at a significance level of 0.001. Failure modes were observed and showed a 100% adhesive fracture. CONCLUSION: It can be concluded that the preparation of large tooth surface preparation might be irrelevant. For zirconia single-retainer RBFPD, only the preparation of a proximal connecting box seems to be a reliable and minimally invasive approach. The differences are statistically significant.

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.

Application of single-retainer all-ceramic resin-bonded fixed partial denture in replacing single anterior tooth / 华西口腔医学杂志

Objective In this study, we aimed to evaluate the clinical effect of single-retainer all-ceramic resin-bonded fixed partial denture (RBFPD) on the single anterior tooth loss patients. Methods A total of 20 single-retainer all-ceramic RBFPD
were fabricated and evaluated in a two-year follow-up observation. The restorations were examined on the basis of the American Public Health Association (APHA) criteria. Results A total of 20 single-retainer all-ceramic RBFPD achieved class A evaluation after a six-month follow-up observation. One single-retainer all-ceramic RBFPD was classified as class B for secondary caries after a one-year follow-up observation. After a two-year follow-up observation, one single-retainer all-ceramic RBFPD was classified as class B because of secondary caries, and one single-retainer all-ceramic RBFPD was classified as class B because of fracture. Conclusion Single-retainer all-ceramic RBFPD is a promising and optional method in replacing single anterior tooth.

Comparison of the effect of transparent film retainer and Hawley retainer / 口腔疾病防治

@#Long-term stability is an important part of orthodontic treatment and wearing a retainer is one of the methods to keep stable after active orthodontic treatment. Transparent film retainer and Hawley retainer are two kinds of retainer usually used in clinical treatment. the previous one is easy to made, comfortable and beautiful to wear, easily damaged. Hawley retainer is relatively complex to made and in a large size. And it is durable and adjustable. However, there are differences between these retainers on the retaining effects in different types of malocclusion. In clinical treatment, according to the type of malocclusion, we choose the appropriate retainer to keep stable occlusal relationship after orthodontic treatment.

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.

Orthodontic fixed retainers: a systematic review / Retenedores fijos en ortodoncia: revisión sistemática

ABSTRACT Introduction: the objective of this study was to evaluate the periodontal effects of fixed retainers in the long term. Methods: a search in electronic databases (PubMed, Cochrane Library, Science Direct, Embase, ProQuest, Ebsco, Biomed Central, Medline, Lilacs, and Google Scholar) and a manual search with no language restrictions. The inclusion criteria were: randomized clinical trials and meta-analysis, prospective and retrospective studies, studies in humans, clinical and radiographical studies evaluating the periodontium, performed during the 1987-2014 period, up to 10 years of follow-up. Four authors extracted data from the selected studies independently. Results: after applying the inclusion criteria, we selected 4 studies in which a total of 405 patients were evaluated. All the studies were longitudinal and retrospective. There was a greater prevalence of gingival recessions, especially in mandibular incisors, which are more vulnerable. There were no significant changes in terms of alveolar bone index or calculus index. The survival rate of fixed retainers was 50% or higher. Due to the heterogeneity of the selected studies, including difference in study population, differences in methods to assess the intervention, and follow-up periods, it was impossible to quantify the variables to perform a meta-analysis. Conclusions: the selected studies had a middle level of evidence. The greatest gingival recessions occurred with the use of fixed retainers in a long time; however, there is no alteration of the alveolar bone level. The studies recommend encouraging patients to maintain good oral hygiene. The findings of this review should be cautiously taken due to the resulting level of evidence, and the general recommendation for clinicians is that, in the long run, these retainers appear to be safe to maintain the alignment of mandibular incisors, although more studies with greater scientific rigor are required. There were no conflicts of interest and this study did not have any kind of financial support.

RESUMEN. Introducción: el objetivo del presente estudio consistió en evaluar los efectos periodontales de los retenedores fijos a largo plazo. Métodos: se realizó una búsqueda en bases de datos electrónicas (PubMed, Cochrane Library, Science Direct, Embase, ProQuest, Ebsco, Biomed Central, Medline, Lilacs y Google Scholar) y una búsqueda manual sin restricción de lenguaje. Los criterios de inclusión fueron: ensayos clínicos aleatorizados y metaanálisis, estudios prospectivos y retrospectivos, estudios en humanos, estudios en los que se evaluara clínica y radiográficamente el periodonto, periodo comprendido entre 1987 y 2014, seguimiento hasta 10 años. Cuatro autores extrajeron independientemente los datos de los estudios seleccionados. Resultados: después de aplicar los criterios de inclusión, se seleccionaron 4 estudios en los que se evaluaron un total de 405 pacientes. Todos los estudios fueron longitudinales retrospectivos. Se encontró una mayor prevalencia de recesiones gingivales, especialmente de los incisivos mandibulares, que son más vulnerables. No mostraron cambios significativos ni el índice de hueso alveolar ni el índice de cálculo. La tasa de supervivencia de los retenedores fijos fue mayor del 50%. Debido a la heterogeneidad de los estudios seleccionados, entre los cuales se encuentra la diferencia en la población de estudio, diferencias en los métodos para evaluar la intervención y el tiempo de seguimiento, fue imposible cuantificar las variables para realizar un metaanálisis. Conclusiones: los estudios seleccionados tuvieron un nivel de evidencia medio. Se presentan mayores recesiones gingivales con el uso de los retenedores fijos a largo plazo; sin embargo, no hay alteración del nivel óseo alveolar. Los estudios recomiendan incentivar al paciente para que mantenga una buena higiene oral. Los resultados de esta revisión se deben tomar con cautela por el nivel de evidencia que arrojaron, y la recomendación general para el clínico es que, a largo plazo, estos retenedores parecen ser seguros para mantener el alineamiento de incisivos mandibulares, aunque se requieren más estudios con mayor rigor científico. No hubo conflictos de intereses y la investigación no contó con ningún tipo de financiamiento.

Stress Distribution in Roots Restored with Fiber Posts and An Experimental Dentin Post: 3D-FEA

Abstract The aim of this study was to compare the stress distribution in radicular dentin of a maxillary canine restored with either a glass fiber post, carbon fiber post or an experimental dentin post using finite element analysis (3D-FEA). Three 3D virtual models of a maxillary canine restored with a metal-ceramic crown and glass fiber post (GFP), carbon fiber post (CFP), and experimental dentin post (DP) were obtained based on micro-CT images. A total of 180 N was applied on the lingual surface of the incisal third of each tooth at 45 degrees. The models were supported by the periodontal ligament fixed in three axes (x=y=z=0). The von Mises stress (VMS) of radicular dentin and the intracanal posts was calculated. The structures of all groups showed similar values (MPa) and distribution of maximum von Mises stress. Higher stress was found in the apical third of dentin while the posts presented homogeneous stress distribution along the axis. The fiber and dentin posts exhibited similar stress values and distribution. Thus, the experimental dentin post is a promising restorative material.

Resumo O objetivo deste estudo foi comparar a distribuição das tensões na dentina radicular de um canino superior restaurado com um pino de fibra de vidro, pino de fibra de carbono ou um pino experimental de dentina por meio do método dos elementos finitos tridimensional (MEF-3D). Três modelos virtuais 3D de um canino superior restaurado com coroa metaloce-râmica e pino de fibra de vidro (PFV), pino de fibra de carbono (PFC) e pino experimental de dentina (PD) foram obtidos baseados em imagens de micro-CT. Uma carga total de 180 N foi aplicada na superfície lingual do terço incisal de cada dente a 45 graus. Os modelos foram suportados pelo ligamento periodontal fixado em três eixos (x=y=z=0). Tensões equivalentes de von Mises (VMS) da dentina radicular e dos pinos intraradiculares foram calculadas. As estruturas de todos os grupos mostraram similar valor (MPa) e distribuição máxima de tensão de von Mises. Elevadas tensões foram encontradas no terço apical da dentina enquanto os pi-nos mostraram distribuição de tensões homogênea em seu longo eixo. Os pinos de fibra e de dentina apresentaram similar valor e distribuição de tensão. Assim, o pino experimental de dentina é um material reabilitador promissor.

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.
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A survey on retention practice among orthodontists in Malaysia / 대한치과교정학회지

OBJECTIVE: The aim of this study was to evaluate retention practices commonly employed by orthodontists. The objectives were to identify the types of retainer frequently used and to investigate the variations in retention practice. METHODS: A total of 97 orthodontists were randomly selected, and a questionnaire consisting of 25 multiple-choice questions sent to them by mail. Upon receiving of the completed questionnaires, the data were statistically analyzed. RESULTS: A total of 32 responses were received; among these, 59.4% of orthodontists' practiced is in a government setting and 40.6% were in private practice. A vacuum-formed retainer was the most commonly used removable retainer for both maxillary (46.9%) and mandibular (46.9%) arches, followed by a Hawley retainer (maxilla, 43.8%; mandible, 37.5%), and a fixed retainer (maxilla, 3.1%; mandible, 9.4%). Of the responding orthodontists, 78.1% prescribed full-time wear (more than 20 h per day) for a duration of 3-9 months for a maxillary arch, compared to 71.9% for the mandibular arch. Only 18.8% of the orthodontists prescribed part-time wear of the retainer for the maxillary arch, compared to 21.9% for the mandibular arch. The majority of orthodontists did not instruct their patients to stop wearing removable retainers (71.9%) or fixed retainers (66.8%) at any specific time and they preferred their patients to continue wearing retainers. CONCLUSIONS: Vacuum-formed retainers are the most commonly used retainers among orthodontists. The majority of orthodontists prescribed full-time wear for more than 20 h per day with a duration of 3-9 months and preferred indefinite use of the retainer.

Critical analysis of fiber post surface treatment: a review / Análise crítica do tratamento de superfície de pinos de fibra: uma revisão

The surface treatment of fiber posts influence the bonding between composite resin cements and intraradicular retainers, being relevant to the prognostic of teeth without coronal structure. This study aimed to evaluate the different fiber post surface treatment protocols described on literature. The search strategy included a review of PubMed/MEDLINE database using fiber post associated with adhesion; bonding; surface treatment; as keywords. Papers not comprehending English language; assessment of post surface treatment; or testing of materials and their physicmechanical properties were excluded. Studies about glass and quartz fiber post surface treatment were considered for this literature review. Among the 190 articles included, silane agent was the material most used (60.52%) for the surface treatment of fiber posts, followed by application of alcoholic solutions (38.29%), and primer and/or adhesive systems (36.84%). Sandblasting of post surface was mentioned in (17.89%), but it affected the physical and mechanical properties. Hydrogen peroxide was mentioned only in 5.78% and it was shown to result on adequate exposure of the glass fibers without damaging them. It was concluded that a consensus for fiber post surface treatment still not exist in the current literature. Among the protocols described, the one using hydrogen peroxide followed by application of silane seems the most promising, since it allows increased bond strengths without fiber damage.

O processo de tratamento da superfície de pinos pré-fabricados de fibra influencia na união entre cimentos resinosos e esses retentores intra-radiculares, sendo relevante para o prognóstico do tratamento restaurador de dentes sem remanescente coronário. Este estudo objetivou avaliar diferentes protocolos de tratamentos de superfície para pinos de fibra descritos na literatura. Como metodologia, realizou levantamento bibliográfico na plataforma PubMed/MEDLINE, com a palavras-chave fiber post associada à adhesion; bonding; surface treatment. Excluíram-se artigos não redigidos em inglês; que não trataram a superfície do pino; e testes de propriedades físicas-mecânicas. Estudos que trataram a superfície de pinos de fibra de quartzo ou vidro foram incluídos. Dentre os 190 artigos incluídos nesta revisão, o agente silano foi o material mais utilizado (60.52%) para tratamento de superfície de pinos de fibra, seguido pela aplicação de álcool (38.29%), e sistema adesivo (36.84%). O jateamento do pino foi mencionado em 17.89%, mas esta técnica resultou em alteração das propriedades físicas e mecânicas. O peróxido de hidrogênio foi mencionado em 5.78% dos manuscritos, entretanto este tratamento permite a adequada exposição das fibras sem danificá-las. Concluiu-se que não consta na literatura protocolo padrão do tratamento da superfície de pinos de fibra. Dentre os protocolos descritos, o protocolo utilizando peróxido de hidrogênio seguido da aplicação do silano aparece como o mais promissor, pois permite resistência de união aumentada sem promover danos as fibras.

Férula de retención o placa Essix como alternativa en ortodoncia: revisión sistemática / Essix retainer as an alternative in orthodontics: a systematic review

Introducción. En esta revisión sistemática se evaluó la efectividad de las férulas o placas Essix como parte de la retención en ortodoncia, la relación costo-beneficio y los posibles efectos secundarios que se pueden presentar con su uso. Métodos. La búsqueda manual de estudios clínicos se llevó a cabo el 29 de agosto de 2013 y, la computadorizada, el 2 de septiembre de 2013. Los criterios de selección fueron: 1) estudios clínicos prospectivos, retrospectivos de asignación aleatoria, y metanálisis; 2) estudios en humanos; 3) estudios que compararan placas Essix con retenedores removibles; 4) pacientes que hubieran terminado el tratamiento de ortodoncia; 5) tiempo de observación de dos años o más; 6) estudios en todos los idiomas; 7) estudios desde 1990 hasta 2013. Resultados. Se encontraron 17 artículos con potencial de inclusión, de los cuales se excluyeron 15 por no cumplir los criterios de selección, lo que resultó en la inclusión de dos estudios solamente. La efectividad de la placa Essix como alternativa de retención es mayor en comparación con la de Hawley; sin embargo, en relación con la retención del ancho intercanino, la longitud del arco inferior y los contactos de oclusión, no hubo diferencias significativas. La relación costo-beneficio y los efectos secundarios no se pudieron evaluar debido a la falta de evidencia. Conclusiones. La placa Essix se encontró más efectiva para mantener la posición de los incisivos inferiores durante el período de retención en comparación con la placa de Hawley; sin embargo, el índice de irregularidad tiende a volver a su valor inicial a los dos años después de la retención.

Introduction: The purpose of this systematic review was to evaluate the effectiveness of Essix retainers, the cost-benefit relationship and its possible side effects. Methods: The manual search was performed on August 29, 2013, and the electronic search was performed on September 2, 2013. The selection criteria were: 1) randomized clinical trials, prospective, retrospective, and metaanalysis; 2) studies in humans; 3) studies comparing Essix retainers with other removable retainers; 4) patients that had fulfilled the orthodontic treatment; 5) observation time: two years or more; 6) no language restriction; 7) studies from 1990 to 2013. Results: Seventeen potential articles were found and 15 of these were excluded. Only 2 studies met the inclusion criteria. There was a tendency of greater effectiveness of Essix retainers in comparison with Hawley retainers, however, in relationship to arch length, oclusal contacts and intercanine width no significant differences were found. The side effects and cost-benefit relationship were undeterminable because of the lack of evidence. Conclusions: The Essix retainers were found to be more effective in maintaining the position of the lower incisors during the retention period in comparison with the Hawley retainer. However, the irregularity index tended to return to its initial value two-year post retention.