Prótese overdenture: sistema o'ring / Overdenture prosthesis: o'ring system

Overdenture é uma prótese total que se caracteriza por usar apoios retentivos para que aumente sua estabilidade e retenção na cavidade bucal, gerando assim menor desconforto ao paciente e melhor adaptação. A Prótese overdenture dentossuportada necessita de elementos dentais remanescentes com canais tratados endodonticamente e que possuam suporte periodontal adequado. O objetivo deste relato de caso clínico é expor a sequência de confecção de uma prótese overdenture dentossuportada maxilar associada a uma prótese total convencional mandibular, com os passos clínicos detalhados por meio de uma abordagem teórica e visual. Esse tipo de reabilitação favorece a adaptação do paciente à nova condição, visto que o uso de próteses totais convencionais pode causar certo desconforto ao paciente devido à falta de retenção e estabilidade. Essa manutenção dos dentes remanescentes favorece à manutenção óssea e a futura decisão do paciente em optar pela instalação de implantes dentários, podendo confeccionar próteses implantorretidas (overdentures) ou implantossuportadas (protocolo).O Paciente demonstrou-se satisfeito com o resultado estético e funcional após a instalação da prótese concretizando que o tratamento é viável(AU)

Overdenture is a denture that utilizing retentive supports for increase stability and retention in oral cavity. The tooth-supported overdenture require dental elements with root canal therapy and good periodontal support. The aim of this study is to report the confection of a maxillary tooth-supported overdenture associated with mandibular denture and your clinical steps. This rehabilitation promotes the patient's adaptation the new condition, since the use of conventional dentures may cause discomfort due to lack of retention and stability. The preservation of dental elements promotes bone maintenance and forthcoming decision of the patient in the installation of dental implants that can choose implantretained or implant-supported prosthesis. Patient was satisfied with aesthetic and functional result after installation of prosthesis(AU)

Cronología de la erupción dentaria en adolescentes de 13 años del municipio Sancti Spíritus

Introducción: La erupción dentaria es un proceso fisiológico que puede ser alterado por múltiples causas congénitas o ambientales. Objetivo: Determinar la cronología de la erupción dentaria permanente y su relación con factores influyentes en adolescentes de 13 años del municipio Sancti Spíritus. Métodos: Se realizó un estudio descriptivo, transversal en el municipio Sancti Spíritus entre septiembre 2017 y junio de 2019. La población estuvo constituida por 1 355 adolescentes de 13 años pertenecientes a todas las escuelas secundarias básicas urbanas de este municipio y por muestreo estratificado en dos etapas se seleccionó una muestra de 406 adolescentes. Se utilizaron métodos del nivel teórico, empírico y estadístico-matemático. Resultados: Se constató que el 22,9 % de los adolescentes presentaron la cronología de la erupción dentaria atrasada respecto a las medidas de Mayoral con predominio del sexo masculino (57 %) y el grupo étnico europoide (83,9 %). Los factores que más influyeron fueron la retención de dientes temporales con 72 %, el sexo con 57 % y los antecedentes hereditarios con 49,5 %, los tres con gran significación estadística. Conclusiones: Casi la cuarta parte de los adolescentes de 13 años estudiados del municipio Sancti Spíritus presentan atraso en la cronología de la erupción dentaria permanente respecto a los valores de Mayoral. Los del sexo masculino presentaron el doble de riesgo para una cronología atrasada y no existieron diferencias en cuanto al grupo étnico. Los factores que más influyeron fueron la herencia, el sexo y la retención de dientes temporales.

Introduction: Tooth eruption is a physiological process that can be altered by multiple congenital or environmental causes. Objective: To determine the chronology of permanent dental eruption and its relationship with influencing factors in 13-year-old adolescents from the Sancti Spíritus municipality. Methods: A cross-sectional descriptive study was carried out in the Sancti Spíritus municipality from September 2017 to June 2019. The population consisted of 1 355 13-year-old adolescents belonging to all the urban basic secondary schools of this municipality and by stratified sampling in two stages. A sample of 406 adolescents was selected. Theoretical, empirical and statistical-mathematical level methods were used. Results: It was found that 22.9% of the adolescents presented delayed dental eruption chronology with respect to the Mayoral measures, with a predominance of males (57%) and the Europoid ethnic group (83.9%). The factors that most influenced were the retention of temporary teeth with 72%, sex with 57% and hereditary history with 49.5%, the three variables with great statistical significance. Conclusions: Almost a quarter of the 13-year-old adolescents studied in the municipality of Sancti Spíritus presents a delay in the chronology of permanent dental eruption with respect to the Mayoral values. Those of the masculine sex presented double the risk for a delayed chronology and there were no differences regarding the ethnic group. The factors that most influenced were heredity, sex and retention of temporary teeth.

A study comparing patient satisfaction and retention of CAD/CAM milled complete dentures and 3D printed CAD/CAM complete dentures versus conventional complete dentures: a randomized clinical trial / Um estudo comparando a satisfação do paciente e a retenção de próteses totais fresadas em CAD/CAM e próteses totais 3D impressas com tecnologia CAD/CAM versus próteses totais convencionais: um ensaio clínico randomizado

Objective: To compare the three different methods of complete denture fabrication assessing patient satisfaction and retention after insertion for six months' follow-up period. Material and Methods: The study was conducted in the Prosthodontic Department where a total of forty-eight patients were recruited from the outpatient clinics fulfilling the inclusion criteria. This study was designed as a randomized controlled clinical trial. All patients followed the steps of complete denture construction till jaw relation record. Then, all eligible patients were randomized to intervention and control groups. For intervention groups digital scanning, designing, manufacturing of complete dentures was done; 3D printing for first and milling for second intervention. For the comparator group, complete dentures were manufactured the conventional way. After 2 weeks of delivery of the dentures, patients received a patient satisfaction questionnaire, retention was measured by retention force gauge. Both readings were also recorded after 3 months and at 6 months. The mean and standard deviation values were calculated for each group in each test. The significance level was set at P≤ 0.05. Results: No statistical difference was found in terms of patient satisfaction and retention between the three groups at different time intervals. Conclusion: The manufacturing technique seemed to have no influence on patient satisfaction and retention with milled showing the least results.(AU)

Objetivo: Comparar três métodos diferentes de fabricação de prótese total avaliando a satisfação do paciente e a retenção após a inserção por um período de acompanhamento de seis meses. Material e Métodos: O estudo foi conduzido no departamento de Prótese onde um total de quarenta e oito pacientes foram recrutados das clínicas ambulatoriais atendendo os critérios de inclusão. Este estudo foi designado como um ensaio clínico randomizado controlado. Todos os pacientes seguiram as mesmas etapas de confecção de prótese total até o registro da relação maxilo-mandibular. Então, todos os pacientes qualificados foram divididos de forma aleatória nos grupos de intervenção e grupo controle. Para os grupos de intervenção foram realizados escaneamento digital, projeto e fabricação de próteses totais; Impressão 3D para o primeiro e fresagem para o segundo grupo de intervenção. Para o grupo de comparação, próteses totais foram feitas com o método convencional. Depois de 2 semanas após a entrega das próteses os pacientes receberam um questionário de satisfação e a retenção foi mensurada com um medidor de força de retenção. Ambas as leituras também foram registradas após 3 e 6 meses. Os valores de média e desvio padrão foram calculados para cada grupo em cada teste. O nível de significância foi estabelecido em P ≤ 0,05. Resultados: Nenhuma diferença estatística foi encontrada em termos de satisfação do paciente e retenção entre os três grupos em diferentes intervalos de tempo. Conclusão: A técnica de fabricação pareceu não ter influência na satisfação do paciente e retenção da prótese, com o grupo fresado apresentando o mínimo de resultados.(AU)

Effects of cone beam computed tomography measurement of maxillary anterior teeth on implant success and patient satisfaction of maxillary anterior teeth / 中国基层医药

Objective:To investigate the effects of cone beam computed tomography measurement of maxillary anterior teeth on implant success and patient satisfaction of maxillary anterior teeth.Methods:120 patients who underwent maxillary anterior teeth implantation in Hangzhou Dental Hospital from October 2017 to October 2019 were included in this study. They were randomly assigned to receive either conventional maxillary anterior teeth implantation (control group, n = 60) or cone beam computed tomography measurement of maxillary anterior teeth and maxillary anterior teeth implantation (study group, n = 60). The implant success rate was compared between the two groups. Alveolar bone thickness and ISQ value immediately, 3 and 12 months after implantation as well as patient satisfaction were compared between the two groups. Results:Implant success rate in the observation group was significantly higher than that in the control group [96.67% (58/60) vs. 85.00% (51/60), χ2 = 4.904, P < 0.05]. In the observation group, alveolar bone thickness at 3 and 12 months after implantation was (1.53 ± 0.05) mm and (1.78 ± 0.12) mm, respectively, which was significantly higher than that in the control group [(1.46 ± 0.04) mm, (1.64 ± 0.10) mm, t = 9.839, 8.066, both P < 0.001]. In the observation group, ISQ value at 3 and 12 months after implantation was (76.83 ± 5.49) and (82.91 ± 4.85), respectively, which was significantly higher than that in the control group [(67.81 ± 4.61), (74.18 ± 5.21), t = 11.324, 11.038, both P < 0.001). Total satisfaction rate in the observation group was significantly higher than that in the control group [95.00% (57/60) vs. 81.67% (49/60), χ2 = 5.175, P < 0.05]. Conclusion:Cone beam computed tomography measurement of maxillary anterior teeth can help increase implant success rate and patient satisfaction.

Retention strength of ball-attachment titanium post for removable partial denture or overdenture

Aim: To evaluate the retention of an endodontic titanium postwith a spherical head for removable partial denture or overdentureattachment according to surface treatment type. Methods: Sixtyhealthy single-rooted teeth, sectioned at the enamel/cementumjunction, were treated endodontically and steadily fixed in theembedding acrylic resin. The titanium posts were subdivided intofour groups: control, no surface treatment (Ctrl); posts with macroretentivegrooves (MR); air abrasion of the post surface (AB); andposts with macro-retentive grooves and air abrasion of the postsurface (MR+AB). The posts were luted in the root canal usingself-adhesive dual resin cement. Pull-out testing was performedusing a universal testing machine until complete detachment wasachieved. After pull-out testing, the metallic posts were examinedunder an optical microscope and the failures were classifiedbased on the cement distribution pattern on the extracted posts:0, no cement left on the post (cement/post failure); 1, postsurface partially covered by adhered cement (post/cement anddentin/cement mixed failure); 2, post surface completely coveredby cement (dentin/cement failure). The retention data wereanalyzed by one-way ANOVA, Bonferroni­Dunn test (p<0.05)and Weibull analysis. Results: AB showed the highest retentionvalue (485.37±68.36), followed by MR+AB (355.80±118.47), MR(224.63±42.54) and Ctrl (113.12 ± 51.32). AB and MR showedthe highest Weibull moduli. Conclusions: The data indicatedthat air abrasion alone could significantly increase the retentionof titanium posts/attachments for use with overdentures orremovable partial denture

Odontoma compuesto como causa de retención dentaria. Presentación de dos casos clínicos / Odontoma compound as a cause of toothretention. Presentation of two clinical cases

RESUMEN Los odontomas son entidades odontogénicas mixtas, compuestas por una mezcla de células odontogénicas epiteliales y mesenquimatosas diferenciadas. Por lo inusual del hecho el objetivo de nuestro trabajo fue presentar un caso de gemelos dicigóticos bivitelinos masculinos de 10 años de edad con presencia de retención dentaria del incisivo central superior derecho en ambos niños causado por la presencia de un odontoma compuesto, cuyo diagnóstico se corrobora clínica e histológicamente La lesión se aprecia como una zona radiolúcida bien definida en la que en su interior se ve una estructura radiopaca similar a un diente. Los odontomas fueron extirpados quirúrgicamente y se realizó una ventana quirúrgica en la zona donde se encontró el incisivo central superior para después enlazarlo y llevarlo al arco ortodóncicamente.

ABSTRACT Odontogenic entities noontimes are mixed, made by a mixture of odontogenic epithelial cells and differentiated mesenchymal. It made unusual aim of our study was to present a case of fraternal dizygotic male 10 years of age with the presence of dental retention upper right central incisor in both children caused by the presence of a compound odontoma, whose diagnosis is confirmed clinically and histologically the lesion is seen as a well-defined radiolucent area which is inside a structure similar to a tooth radiopaque. Odontomas were surgically removed and underwent surgical window in the area where they found the upper central incisor and then link it and take it to the orthodontic arch.

Evaluation of the maladaptation of the test base in acrylic resin regarding the technique of preparation, place of measurement and storage time / Avaliação da desadaptação da base de prova em resina acrílica em relação à técnica de confecção, local de mensuração e tempo de armazenagem

Introduction: The most used material for the preparation of the baseplates is the acrylic resin, but it can present distortions. Objective: To evaluate preparation technique, region and storage time that presents less maladaptation of the base when made with self-cured acrylic resin. Material and method: Models were created in gypsum type III simulating edentulous maxilla, as divided into 3 groups (n = 10): GC (control group) thermopolymerizable acrylic resin; G1 - manual adaptation technique and G2 - drip technique. For the measurements, silicone by condensation of light consistency that was interposed between base and model was used. With a hydraulic press, 50 kg pressure was applied leading the base of the model. The obtained mold was measured in the palate, canine and molar regions with a digital caliper at the following times: immediately after the base polymerization, at 24, 48, 72, 96 hours and one week. The results were submitted to statistical analysis. Result: G1 presented maladaptation of 0.43 mm ± 0.10, while G2 obtained 0.39 mm ± 0.11. The lowest maladaptation occurred in the CG. The palate region presented greater maladaptation (0.52 ± 0.07) and the canine region, the lowest (CD = 0.27 mm ± 0.07 and CE = 0.27 ± 0.09); There was no statistically significant difference for storage times. Conclusion: G2 presented lower values than G1, with no statistically significant difference. The palate region presented greater maladaptation, followed by molars and canines. The bases continued to maladaptation the model after the immediate polymerization, with no statistically significant difference.

Introdução: O material mais empregado para confecção da base de prova é a resina acrílica por oferecer maior rapidez e praticidade, embora tenda a maior distorção. Objetivo: Avaliar técnica de confecção, região e tempo de armazenagem que apresente menor desadaptação da base de prova confeccionada com resina acrílica ativada quimicamente. Material e método: Confeccionaram-se modelos em gesso tipo III simulando maxila edêntula que foram divididos em 3 grupos (n = 10): GC - (grupo controle) resina acrílica termopolimerizável; G1 - técnica da adaptação manual; e G2 - técnica do gotejamento. Para as mensurações utilizou-se silicone por condensação de consistência leve que foi interposto entre base e modelo. Com uma prensa hidráulica aplicou-se pressão de 50 kg levando a base de encontro ao modelo. O molde obtido foi mensurado nas regiões de palato, caninos e molares com paquímetro digital nos seguintes tempos: imediatamente após a polimerização da base, em 24, 48, 72, 96 horas e uma semana. Os resultados foram submetidos à análise estatística. Resultado: O G1 apresentou média de desadaptação de 0,43mm±0,10, enquanto o G2 obteve 0,39 mm ± 0,11. Os menores valores de desadaptação ocorreram no GC; A região do palato apresentou maior desadaptação (0,52 mm ± 0,07) e a região de caninos, as menores (CD = 0,27 mm ± 0,07 e CE = 0,27 ± 0,09); Não houve diferença estatisticamente significante para os tempos de armazenagem. Conclusão: O G2 apresentou menores valores que o G1, sem diferença estatisticamente significante; A região de palato apresentou maior desadaptação, seguida de molares e caninos; As bases continuaram desadaptando ao modelo após a polimerização imediata, sem diferença estatisticamente significante.

A new method for evaluating the retentive efficacy of different denture adhesives

Aim: The aim of this study was to evaluate a new method for measuring the retention values of different denture adhesives. Methods: The adhesive strength values of three different commercial denture adhesives (Corega powder, Corega adhesive tape and Ultra Corega cream) were evaluated using three different moisturizing agents (distilled water, artificial saliva and natural saliva). The adhesive test was performed on a universal testing machine, after applying the adhesive products to acrylic resin specimens, under two different test conditions (wetting or dipping). Tensile bond strength values in MPa were obtained for each denture adhesive presentation and test condition. Viscosity of the denture adhesives mixed with the different moisturizing agents was determined using a rotary rheometer. Maximum viscosity values were analyzed using the one-way ANOVA test. Tensile bond strength data was analyzed using Kruskal-Wallis and the Tukey's test. Pooled data of each denture adhesive presentations for all test conditions was also carried out. Correlation between viscosity and pooled tensile strength values was analyzed through linear regression analysis. A significance level of α=0.05 was set for all analyses. Results: Results showed that statistically higher adhesion strength was obtained with tape and cream adhesives when using natural saliva as moisturizing agents (p<0.05). The adhesive strength values obtained with the dipping method were similar to those obtained with the conventional wetting method. The denture retention strength was influenced by both the denture adhesive type and moisturizing agent used. Conclusion: The dipping method showed to be a reliable test capable to simulate the oral conditions and should be better explored in further studies

Como utilizar o conceito da Zona Neutra para otimizar a Prótese / Using the Neutral Zone concept to improve the lower complete

Este artigo descreve os passos para a utilização da filosofia da Técnica da Zona Neutra. Através dessa filosofia, procura-se localizar uma área, em boca, onde as forças geradas pela língua são neutralizadas pelas forças geradas pelos lábios e bochechas, estabilizando assim a prótese.

This article describes step-by-step the application of the Neutral Zone technique philosophy. It is based upon the concept that for each individual patient, there is within the denture space a specific area where the function of the musculature will not unseat the denture and where forces generated by the tongue are neutralized by the forces generated by the lips and cheeks.

Influence of different surface treatments of fiberglass posts on the bond strength to dentin

Aim: To assess the influence of different fiberglass post surface treatments on the bond strength (BS) to root dentin. Methods: Thirty bovine root canals were endodontically treated and filled with gutta-percha and AH Plus sealer. At 24 h after the endodontic filling, the post spaces were prepared with Gates-Glidden drills and #3 drills of the DC White Post system, maintaining a 4 mm apical seal. The roots were randomly divided into three groups: S (fiberglass posts treated with silane), SA (fiberglass posts treated with silane and a hydrophobic adhesive system) and SHA (fiberglass posts treated with silane, followed by drying with hot air). The posts were cemented with a selfadhesive cement (RelyX U200). The specimens were stored in distilled water at 37 °C for 24 h and subjected to the push-out test (0.5 mm/min). Data were statistically analyzed using one-way ANOVA and Tukey's test (α=0.05) Results: SA and SHA groups showed the highest BS mean values (11.29 and 10.85 MPa, respectively), while the S group presented the lowest BS mean value (7.21 MPa). S group was significantly different from SA and SAH groups. Conclusions: The surface treatment of fiberglass posts influenced BS values (Au)

Onde se encontra o travamento posterior da maxila de uma prótese total superior? / Where is the postpalatal seal in a complete upper denture?

Na confecção de uma prótese total superior, a delimitação correta do travamento posterior é uma responsabilidade do clínico. Para evidenciá-lo, esse deve basear-se em referências anatômicas e fatores fisiológicos individuais de cada paciente.

During the fabrication of a complete denture the practitioner is responsible for a proper postpalatal seal. Thus it must be based on anatomic structures and physiologic aspects of each patient.

Retenção e estabilidade em prótese total convencional ­ revisão de literatura 0 / Retention and stability in total convencional prosthesis ­ literature review

O sucesso das próteses totais depende, fundamentalmente, do aproveitamento total da área basal, da perfeita adaptação das bases a esta área, e da justeza da borda ao fórnix, desta forma, o resultado será uma adequada retenção. Entretanto, a retenção obtida será comprometida se os "princípios fundamentais da estabilidade", que são os grandes responsáveis pela sua manutenção, não forem obedecidos. O presente estudo tem como objetivo fazer uma revisão da literatura sobre a retenção e estabilidade de próteses totais convencionais.

The success of the retention of total prosthesis depends fundamentally on the full use of basal area, on the perfect adaptation of the bases to this area, and on the fairness of the edge to a fornix. however the obtained retention can be compromised when fundamental principles of stability ­ responsible for its maintenance ­ are not followed. The aim of the present study is to conduct a literature review on the retention and stability of total conventional prosthesis.

Primary stability of mini-screw：buccal cortical thickness in maxillary posterior area of malocclusion / 中国组织工程研究

BACKGROUND:Mini-screw stability is primarily related to alveolar bone cortical thickness. It is necessary to learn cortical thickness to choose suitable implanting sites and predict success rate. OBJECTIVE:To evaluate the buccal cortical thickness in maxilary posterior area of Class II Division I malocclusion adolescents. METHODS: Fifty-two adolescents (including 26 male and 26 female) of Class II Division I malocclusion scanned by Cone Beam Computer Tomography were involved in this study. The buccal cortical thickness of six posterior interradicular sites (14-15, 15-16, 16-17, 24-25, 25-26, 26-27) at four bone levels (2, 4, 6, 8 mm) from the alveolar crest in both boys and girls were measured. RESULTS AND CONCLUSION: (1) There was no statisticaly significant difference in alveolar cortical thickness between left and right sides in the girls (P > 0.05); cortical thickness of 5-6 and 6-7 at 8 mm was thicker than that at 2 mm (P 0.05). Al sites in this study were suitable for mini-screw implantation; from the first molar to posterior dental arch, buccal cortical thickness is wel-distributed; it is dangerous for implantation in the areas around the first molar more than 6 mm, where the frequent presence of the maxilary sinus is observed. There is an increase of buccal cortical thickness from crest to base of alveolar crest, obtaining good initial stability.

Evaluación ex vivo de la retención de estructuras en zirconia-ytria de Procera® con diferentes cementos / Ex vivo evaluation of the retention of Procera® zirconia- yttria systems with different cements

Introducción: en tanto no se encuentra en la literatura un protocolo fundamentado de cementación para restauraciones elaboradas en zirconia-ytria, el propósito de este estudio fue evaluar ex vivo la retención por resistencia friccional de estructuras de zirconia-ytria, Procera® , cementadas con cuatro materiales como el Ketac cem (3M ESPE), el Multilink Automix (Ivoclar Vivadent), el Panavia F 2.0 (Kuraray) y el RelyX U100 (3M ESPE), sobre dientes naturales. Métodos: se obtuvieron 40 terceros molares recientemente extraídos, los cuales fueron desinfectados con NaOCl al 0,5%, y almacenados en solución salina, embebidos en resina acrílica y tallados con ángulo de convergencia de 10° por pared, tallado axial con profundidad de 1,5 mm y altura de 4 mm. Se tomaron impresiones con Aquasil Ultra® Dentsply y vaciadas con yeso tipo IV, para hacer 40 estructuras Procera AllZircon (Nobel Biocare). Se cementaron 10 muestras por cada material y fueron termocicladas x 5.000 ciclos de 15 s. Luego fueron traccionadas con una máquina de pruebas universal y se analizaron los tipos de fallas en las diferentes interfases. Se hizo análisis estadístico ANOVA de una vía y análisis de rangos múltiples. Resultados: los valores promedio de retención en Newtons fueron de 440 N para el Ketac cem, de 698 N para el Multilink Automix, de 686 N para el Panavia F 2.0 y de 551 N para el RelyX U100. La falla adhesiva a la dentina se presentó en el 53,8%, seguido por la falla mixta, con el 12,82%. Conclusiones: los cementos resinosos con monómeros de fosfato ácidos reportan valores superiores en la retención en comparación con cementos convencionales tipo ácido-base. La adhesión a dentina y la manipulación de los cementos pueden influir en el resultado final.

Introduction: since the specialized literature does not report reliable protocols for cementing zirconia-yttria restorations, the purpose of this study was to perform an ex vivo assessment of the retention by frictional strength of Procera® zirconia-yttria systems cemented with four materials: Ketac Cem (3M) ESPE), Multilink Automix (Ivoclar Vivadent), Panavia F 2.0 (Kuraray), and RelyX U100 (3M ESPE) on natural teeth. Methods: We gathered 40 recently extracted third molars, which were disinfected with 0.5% NaOCl and stored in saline solution, embedded in acrylic resin, and cut at a 10° convergence angle per wall with an axial carving of 1.5 mm in depth and 4 mm in height. Impressions were taken with Aquasil Ultra® Dentsply and cast with type IV plaster, obtaining 40 Procera AllZircon (Nobel Biocare) structures. 10 samples per material were cemented and thermocycled x 5,000 cycles of 15 s. They were then tractioned with a universal testing machine and failure types at the different interfaces were analyzed. One-way multiple-range ANOVA statistical analysis was performed. Results: average retention values in Newtons were 440 N for Ketac Cem, 698 N for Multilink Automix, 686 N for Panavia F 2.0, and 551 N for RelyX U100. Dentin adhesion failure occurred in 53.8% of cases, followed by mixed failure, with 12.82%. Conclusions: resinous cements with acid phosphate monomers reported higher retention values in comparison with conventional acid-base cements. Adherence to dentin and cement handling can affect the final result.

The influence of mandibular ridge anatomy on treatment outcome with conventional complete dentures

Since prognostic indicators are likely to take on increasingimportance as a diagnostic tool for selection of patients forimplant provision, this study investigated the influence of theshape and resiliency of the mandibular alveolar ridge on theretention and stability of conventional complete dentures. Ninety-three edentulous patients wearing both maxillary andmandibular conventional complete dentures composed the sample.Data were collected regarding shape and resiliencyof themandibular residual ridge. Dentures were assessed for retentionand stability using an objective and reproducible tool.The associationsbetween the clinical characteristics of the mandibularalveolar ridge and denture retention and stability were analyzedusing chi-square and Fisher exact tests (α = 0.05). A significantassociation between ridge shape and denture stability (p < 0.05)was found, while ridge resiliency was significantly associated todenture retention (p < 0.001). Based on the results, mandibularridge shape and resiliency influenced the retention and stabilityof conventional complete dentures...

Success and survival rates of mandibular overdentures supported by two or four implants: a systematic review

This systematic review evaluated the influence played by the number of implants on the results of rehabilitation treatment with mandibular overdentures on 2 or 4 implants. The literature search was conducted using PubMed, Embase and Cochrane databases. Specific terms were used in performing a search from January 1980 to January 2013. The search strategy was applied by two reviewers who extracted the data and compared the results. Discrepancies were resolved by discussion. Great heterogeneity was seen among the selected studies, in regard to survival rates, prosthesis failure and function rates. A medium degree of quality and methodological consistency was found in one study, and no studies showed a high degree. When considering the prosthesis success rate for 2 implants, there was a variation of 23% to 100%. However, when considering the survival rate, the result was 92% to 100%. For 4 implants, prosthesis survival rates showed less variation, i.e., 97.7% to 100%. Ball attachments were the most common type of abutment for 2 implants; however, there was a higher prevalence of bar abutments for 4 implants. Rehabilitations with 2 implants showed more complications and required more maintenance according to the connection type. Given the limitations of this review, mandibular overdentures with 4 implants showed better results with respect to survival and success rates, especially those with a bar connection. Further studies comparing these two treatment types are necessary to improve the scientific evidence in this area.

Wear of double crown systems: electroplated vs. casted female part

OBJECTIVES: The wear of telescopic crowns is a common problem often reducing the patient's satisfaction with the denture and resulting in a renewal of the denture. The study aims to compare the wear behavior of conical crowns using electroplated copings (group E ) with standard telescopic crowns with cast female parts (group C). MATERIAL AND METHODS: 10 conical crowns were milled for each group of a cast gold alloy. The specimen of group E had a conicity of 2º. The cast secondary crowns of group C had a 0º design. The electroplated coping was established by direct electroforming. An apparatus accomplishing 10,000 wear cycles performed the wear test. The retentive forces and the correlating distance during insertion and separation were measured. The wear test was separated in a start phase, an initial wear phase and the long term wear period. The retention force value and the force-distance integral of the first 0.33 mm of each cycle were calculated. RESULTS: The retentive forces were significantly higher for group E and the integrals were significantly lower for this group except the integral at cycle 10,000. The changes of retention force and integral did not differ significantly between both groups in all phases. The change of the integrals as well as the integral at the particular cycles showed higher interquartile distances for group C. CONCLUSIONS: Within the limitations of this study the tested conical crowns showed clinically acceptable retentive properties. The values reached a range comparable to retentive elements tested in recent literature. The values of group C showed higher ranges. The force measured for group E was significantly higher than for group C but the integrals showed an opposite tendency. The results indicate that an exclusive analysis of the force is not sufficient as the integral is not equivalent to the force although it describes the retentive property of the system in a better way than the force over a distance is described. Both systems seem to be suitable for clinical practice.

Comportamento de desgaste “in vitro” de encaixes de precisão extracoronários / “In vitro” wear behavior of extracoronal precision attachments

The objective of this study was to evaluate the retentive ability and weight change of two extracoronal attachments after repeated insertion/removal cycles. Material and methods: Two extracoronal attachments were used, one with plastic inserts and the other one with conventional metal-alloy. Initial retentive ability was checked under a 20kgf load cell at 5mm/min. The weight of the fixed/removable pairs was verified with an electronic mass comparator. Fixed/removable pairs were tested with an insertion/removal cycling machine, for 5800 cycles (corresponding to 5 years) at a speed of 32 rpm speed. Insertion/ removal cycles were performed under artificial saliva. Weight change and retentive ability of attachments were verified at baseline, six-month, one-year, two-year, three-year, four-year and five-year time intervals. The two-way ANOVA for repeated measurements test was used to verify possible interactions between precision attachment type and retentive ability/weight change over time. Statistically significant associations were found between attachment type and retentive ability over time (P=0.006). Metal-alloy group showed signifi cant differences between baseline and first year (P=0.005), baseline and second year (P=0.001), and between baseline and five years (P=0.035) of insertion/removal cycles. In the plastic insert group, no significant differences were found over time. No statistically significant associations were found between precision attachment types and weight change over time (P=0.643). Initial retentive ability can not be standardized for both attachments; the metal-alloy showed better performance than the plastic insert after five years. Both attachments did not show weight change after five years of simulated use.

O objetivo deste estudo foi avaliar a capacidade retentiva e a alteração do peso de dois encaixes extracoronários após repetidos ciclos de inserção e remoção. Materiais e métodos: Dois encaixes extracoronários foram usados, um com fêmea em plástico e o outro em metal. A capacidade retentiva inicial foi verificada em uma máquina de ensaio universal com célula de carga de 20kgf a velocidade de 5mm/min. O peso do conjunto macho/fêmea foi verificado com uma balança eletrônica. Os conjuntos macho/fêmeas foram testados em um simulador de ciclos por 5800 vezes (correspondendo a 5 anos) a uma velocidade de 32 rpm. Os ciclos de remoção e inserção foram realizados com saliva artificial. A alteração de peso e a capacidade retentiva dos encaixes foi verificada inicialmente e nos intervalos de tempo de 6 meses, um, dois, três, quarto e cinco anos. O teste ANOVA foi usado para verificar possíveis interações entre o tipo de encaixe e a capacidade retentiva/alteração de peso com o tempo de uso. Associação estatisticamente significativa foi encontrada entre o tipo de encaixe e a capacidade retentiva com o tempo de uso (P=0.006). O grupo metálico mostrou diferença significante entre o tempo inicial e o primeiro ano (P=0.005), tempo inicial e o segundo ano (P=0.001), e entre o tempo inicial e cinco anos (P=0.035) de inserção e remoção. No grupo com fêmea de plástico, não foram encontradas diferenças significativas. Associações estatisticamente significativas não foram encontradas entre os tipos de encaixes e a alteração de peso em tempo algum. (P=0.643). A capacidade retentiva inicial não pode ser padronizada nos dois encaixes; o grupo com fêmea em metal mostrou melhor performance retentiva que o grupo com fêmea em plástico após cinco anos. Ambos encaixes não mostraram alteração no peso após uso simulado de cinco anos.

Influence of Tongue In Complete Denture Retention And Stability.

It is very difficult to relate the anatomical sciences to clinical dentistry, but there is an ever growing need to do so. Especially in fabrication of complete denture, it is important to understand the anatomy, size, position and classification of the tongue and surrounding musculature without which it impossible to achieve proper retention and stability of the complete denture. This paper tries to discuss the various factors that influence the retention and stability and ways to overcome those difficulties

Satisfação de pacientes portadores de sobredentaduras mandibulares implanto-retidas e muco-suportadas / Satisfaction of patients wearing implant-retained and tissue-supported mandibular overdentures

Objetivo: Avaliar a satisfação de indivíduos portadores de sobredentaduras mandibulares implanto-retidas e mucosuportadas relacionando número de implantes e tipos de retentores. Método: Foram avaliados pacientes oriundos das clínicas dos Cursos de Pós-Graduação em Implantodontia da Faculdade de Odontologia da Universidade Federal Fluminense, por meio de entrevistas e avaliação de seus prontuários, nos quais haviam sido instalados 140 implantes osseointegráveis e 40 sobredentaduras implanto-retidas e muco-suportadas. Cerca de 70% destes pacientes estavam no grupo etário acima de 60 anos e a maioria portava prótese total convencional no arco antagonista. Foi feito o levantamento da quantidade de implantes e tipos de retentores utilizados nas reabilitações bucais destes pacientes, e avaliadas as relações entre estas situações e a satisfação dos pacientes quanto à: função, retenção e satisfação geral. As respostas possíveis variavam de muito insatisfeito a muito satisfeito. Resultados: Observou-se que, em todas as situações avaliadas, mais de 87% das respostas fornecidas pelos pacientes quanto à satisfação era de muito satisfeitos a satisfeitos. Sendo o item retenção o de menor valor e a satisfação geral o de maior valor. Conclusão: Independente da quantidade de implantes (2, 3 ou 4) e dos diferentes tipos de retentores utilizados (bola encaixe ou barra encaixe), não houve variação considerável na satisfação dos pacientes portadores de sobredentaduras mandibulares implanto-retidas e muco-suportadas, visto que a maioria deles se declarou satisfeitos ou muito satisfeitos com as categorias incluídas neste estudo.

Objective: To evaluate the satisfaction of individuals wearing implant retained and tissue-supported mandibular overdentures relating the number of implants and the types of retainers. Method: Patients attending the clinics of the Postgraduate Program in Implantology of the Dental School of the Fluminense Federal University were evaluated by means of interviews and review of their dental charts, revealing 140 osseointegrated implants and 40 implant-retained and tissue-supported mandibular overdentures. Approximately 70% of these patients were 60 years of age or more, and most of them wore conventional complete dentures in the maxillary arch. The number of implants and the types of retainers used in the oral rehabilitation of these patients were determined, and the relationships between these issues and patients' satisfaction regarding function, retention and general satisfaction were assessed. The possible responses ranged from very unsatisfied to very satisfied. Results: In all situations evaluated in the study, 87% of the patients' responses regarding satisfaction varied between very satisfied and satisfied. Type of retention scored the lowest values and general satisfaction scored the highest values. Conclusion: Regardless of the number of implants (2, 3 or 4) and types of retainers (ball or bar attachments), there was no significant variation in the satisfaction of patients wearing implant-retained and tissue-supported mandibular overdentures, since most of them declared themselves as satisfied or very satisfied with the factors examined in this study.