Variations in teaching of removable partial dentures in Spanish dental schools

Objectives: Despite the increasing demand for implant-based treatments, removable partial dentures (RPDs) are frequently used in the oral rehabilitation of partially dentate patients. Furthermore, the Bologna Declaration Agreement (1999) promotes the freedom of movement both of students among dental schools and of graduates across the European Union (EU). Given that inconsistency in teaching among dental schools may lead to confusion, this study aimed to evaluate the status of teaching and clinical experience reached by undergrad uate dentalstudents in Spanish dental schools in relation to RPDs. Study design: A questionnaire seeking information on the preclinical and clinical teaching of RPDs was emailed to all Spanish dental schools (11 public, 4 private) with complete undergraduate degree dental programmes in November 2009. Descriptive statistical data analysis was performed. Results: A 100% response rate was obtained. The average duration of the preclinical course in Spain was 44 hours (38 hours in the public chools and 60.5 hours in the private schools). However, public schools reported a greater number of RPDs made per student prior to graduation, with an average of 3.4 acrylic (range: 1-20) and 3.4 cobaltchromium (range: 1-20) RPDs. The corresponding means for private schools were 1 acrylic (range: 0-2) and 2.3 cobalt-chromium (range: 1-4). One public school (9%) stated that they were teaching RPDs using Problem-Based- Learning.Conclusions: Similar to that noted in previously surveyed countries, variations in teaching programmes and clinical experience concerning RPDs achieved by Spanish dental students were evident. While diversity of teaching is often considered to be of benefit, dental students must be adequately trained to ensure that they meet the needs of the patients they will serve during their careers. © Medicina Oral S. L

Ajuste de estructuras coladas para prótesis fija sobre pilares prefabricados de implantes dentales

INTRODUCCIÓN: La falta de ajuste pasivo compromete el funcionamiento biomecánico de las prótesis sobre implantes, constituyendo una de las principales causas de fracaso. OBJETIVOS: Cuantificar el desajuste vertical de estructuras coladas cementadas sobre pilares prefabricados de implantes dentales y evaluar si existen diferencias en cuanto a la discrepancia vertical en función de la aleación y diseño de los colados. MATERIAL Y MÉTODO: Colamos 90 estructuras utilizando tres aleaciones (cobalto-cromo, titanio y paladio-oro) y dos diseños (coronas y puentes de tres piezas con póntico intermedio). Posteriormente cementamos los colados a los pilares y medimos el desajuste vertical de las probetas con un M.E.B. RESULTADOS: En cuanto a la aleación, el cobalto-cromo es el que ofrece peores valores de ajuste vertical, con diferencias estadísticamente significativas respecto las otras dos aleaciones. Atendiendo al diseño, no hallamos diferencias significativas entre coronas y puentes. Considerando las estructuras unitarias, el grupo de cobalto-cromo presenta diferencias significativas respecto a las otras dos aleaciones, siendo el que peor ajuste vertical proporciona. Por último, dentro de las estructuras para puentes, únicamente encontramos diferencias significativas con un nivel de confianza del 90% entre el cobalto-cromo y el paladio-oro. DISCUSIÓN: Nuestros resultados concuerdan con los valores registrados por la mayoría de autores consultados, en estudios in vitro de prótesis fija cementada dento e implantosoportada. CONCLUSIONES: 1. El grupo de colados de cobalto-cromo es el que mostró mayores discrepancias verticales respecto a los colados de paladio-oro y titanio, tanto en lo que se refiere a los colados unitarios como a las estructuras de puentes. 2. No se registraron diferencias significativas de ajuste vertical entre los colados de paladio-oro y los de titanio en los casos estudiados. 3. Comparando las estructuras coladas unitarias con las estructuras coladas para puentes con independencia de la aleación, no encontramos diferencias significativas respecto al ajuste vertical

Curricula for the teaching of complete dentures in Spanish and Portuguese dental schools

Objectives: Given the need to ensure that dentists are sufficiently skilled to offer the best possible care to their patients, this study aims to evaluate the teaching methods and clinical experience achieved by undergraduate dental students in Spain and Portugal as regards complete dentures. Study design: In February 2011, a questionnaire seeking information about the preclinical and clinical teaching of complete dentures was e-mailed to all Spanish and Portuguese dental schools with fully developed undergraduate degree dental programs. Results: A response rate of 82.6% was obtained. The distribution of lectures and hours spent at the laboratory and in clinical activities revealed that teaching complete dentures is eminently a practical issue, this being mostly performed by full-time prosthodontists. All surveyed schools teach the design of the record base, and most of them instruct students in the mounting of teeth in wax. Most schools (94.7%) used a semiadjustable articulator, alginate for primary impressions (73.7%) and elastomeric materials in border-molded custom trays for final impressions (68.4%). In most schools, within the clinical setting students work in pairs, the mean student/ professional staff member ratio being 2.3 ± 0.7. Most schools perform a competence-based assessment (83.3%), although innovative techniques such as problem-based learning are still rarely applied. On average, the students emplaced 1.8 ± 1.2 complete dentures during their clinical training, ranging from 0 to 4, although no clear trend was seen as regards the minimum number of dentures to be made for graduating. Conclusions: Variations in teaching programs and clinical experience concerning complete denture curricula among Spanish and Portuguese dental schools are evident, but all the schools base their teaching mainly on preclinical and clinical practice. However, the low number of dentures made by student per year seems insufficient to ensure clinical skills and cope with social needs

Resistance to bond degradation between dual-cure resin cements and pre-treated sintered CAD-CAM dental ceramics

Objective: To evaluate the bond stability of resin cements when luted to glass-reinforced alumina and zirconia CAD/CAM dental ceramics. Study design: Eighteen glass-infiltrated alumina and eighteen densely sintered zirconia blocks were randomly conditioned as follows: Group 1: No treatment; Group 2: Sandblasting (125 µm Al2O3-particles); and Group 3: Silica-coating (50 µm silica-modified Al2O3-particles). Composite samples were randomly bonded to the pre-treated ceramic surfaces using different resin cements: Subgroup 1: Clearfil Esthetic Cement (CEC); Subgroup 2: RelyX Unicem (RXU); and Subgroup 3: Calibra (CAL). After 24 h, bonded specimens were cut into 1 ± 0.1 mm2 sticks. One-half of the beams were tested for microtensile bond strength (MTBS). The remaining one-half was immersed in 10 % NaOCl aqueous solution (NaOClaq) for 5 h before testing. The fracture pattern and morphology of the debonded surfaces were assessed with a field emission gun scanning electron microscope (FEG-SEM). A multiple ANOVA was conducted to analyze the contributions of ceramic composition, surface treatment, resin cement type, and chemical challenging to MTBS. The Tukey test was run for multiple comparisons (p < 0.05). Results: After 24 h, CEC luted to pre-treated zirconia achieved the highest MTBS. Using RXU, alumina and zirconia registered comparable MTBS. CAL failed prematurely, except when luted to sandblasted zirconia. After NaOClaq storage, CEC significantly lowered MTBS when luted to zirconia or alumina. RXU decreased MTBS only when bonded to silica-coated alumina. CAL recorded 100 % of pre-testing failures. Micromorphological alterations were evident after NaOClaq immersion. Conclusions: Resin-ceramic interfacial longevity depended on cement selection rather than on surface pre-treatments. The MDP-containing and the self-adhesive resin cements were both suitable for luting CAD/CAM ceramics. Despite both cements being prone to degradation, RXU luted to zirconia or untreated or sandblasted alumina showed the most stable interfaces. CAL experimented spontaneous debonding in all tested groups. Key words:CAD/CAM ceramic, alumina, zirconia, resin cement, surface pre-treatment, sandblasting, silica-coating, chemical aging, bond degradation, microtensile bond strength

In vitro comparative study of fibroblastic behaviour on polymethacrylate (PMMA) and lithium disilicate polymer surfaces

Polymethyl methacrylate (PMMA) and lithium disilicate are widely used materials in the dental field. PMMA is mainly used for the manufacture of removable prostheses; however, with the incorporation of CAD-CAM technology, new applications have been introduced for this material, including as a provisional implant attachment. Lithium disilicate is considered the gold standard for definitive attachment material. On the other hand, PMMA has begun to be used in clinics as a provisional attachment until the placement of a definitive one occurs. Although there are clinical studies regarding its use, there are few studies on cell reorganization around this type of material. This is why we carried out an in vitro comparative study using discs of both materials in which human gingival fibroblasts (HGFs) were cultured. After processing them, we analyzed various cellular parameters (cell count, cytoskeleton length, core size and coverage area). We analyzed the surface of the discs together with their composition. The results obtained were mostly not statistically significant, which shows that the qualities of PMMA make it a suitable material as an implant attachment

Effect of alloy type and casting technique on the fracture strength of implant-cemented structures

Objectives: To evaluate the influence of alloy type and casting procedure on the fracture strength (FS) of metallic frameworks for implant-supported fixed prostheses. Study design: Thirty three-unit structures for lower posterior bridges were waxed-up and randomly assigned to two groups (n=15) according to alloy type and casting technique: Group 1 (C): cobalt-chromium cast in a centrifugal machine (TS1, Degussa-Hüls); Group 2 (T): titanium cast in a pressure-differential device (Cyclarc II, Morita). Each structure was cemented onto two prefabricated abutments under a constant seating pressure. After 6 months of water aging, samples were loaded in a static universal testing machine (EFH/5/FR, Microtest) until fracture. Axial compressive loads were applied at the central fossa of the pontics. FS data were recorded and surface topography of the fractured connectors was SEM-analyzed. A Chi-Square test was performed to assess the dependence of pores on the alloy type and casting procedure. ANOVA and Student-Newman-Keuls (SNK) tests were run for FS comparisons (p<0.05). Results: One third of the C structures showed pores inside the fractured connectors. T frameworks demonstrated higher FS than that of C specimens exhibiting pores (p=0.025). C samples containing no pores recorded the greatest mean FS (p<0.001). Conclusions: Fracture strength of metallic frameworks depended on the alloy type and casting procedure. Cobalt-chromium casts often registered pores inside the connectors, which strongly decreased the fracture resistance. An accurate casting of titanium with a pressure-differential system may result in the most predictable technique under the tested experimental conditions. © Medicina Oral S. L

Oral health-related quality of life in complete denture wearers depending on their socio-demographic background, prosthetic-related factors and clinical condition

Objectives: To investigate the differences in impact on oral health-related quality of life (OHRQoL) among complete denture wearers depending on their socio-demographic characteristics, prosthetic-related factors and oral status. Study Design: 51 patients aged 50-90 years treated, from 2005 to 2010, with at least one complete denture at the Department of Buccofacial Prostheses of the Complutense University (Madrid) were enrolled in this cross- sectional study. All of the participants answered the Oral Health Impact Profile (OHIP-14sp) questionnaire. The additive scoring method was used. The prevalence of impacts was calculated by using the occasional threshold (OHIP-14sp score > o =2). Socio-demographic and prosthetic-related variables were gathered. Patients underwent clinical examination to assess their oral condition. Descriptive probes and Chi-Square tests were run (p < o =0.05). Results: The predominant participants' profile was that of a man with a mean age of 69 years wearing complete dentures in both the maxilla and the mandible. The prevalence of impact was 23.5%, showing an aver - age score of 19±9.8. The most affected domains were "functional limitation" and "physical pain", followed by "physical disability". Minor impacts were recorded for the psychological and social subscales ("psychological discomfort", "psychological disability", "social disability" and "handicap"). The prosthesis' location significantly influenced the overall patient satisfaction, the lower dentures being the less comfortable. Having a complete re - movable denture as antagonist significantly hampered the patient satisfaction. Patients without prosthetic stomatitis and those who need repairing or changing their prostheses, recorded significantly higher OHIP-14sp total scores. Conclusions: The use of conventional complete dentures brings negative impacts in the OHRQoL of elderly patients, mainly in case of lower prostheses that required reparation or substitution, with a removable total denture as antago - nist. The prosthetic stomatitis in this study was always associated to other severe illness, which may have influenced the self-perceived discomfort with the prostheses, as those patients were daily medicated with painkillers

Prospective double-blind clinical trial evaluating the effectiveness of Bromelain in the third molar extraction postoperative period

Objectives: To evaluate the anti-inflammatory and analgesic effect of Bromelain (pineapple extract) administered orally in the postoperative after extraction of impacted lower molars. Study Design: This is a prospective, placebo-controlled, unicentric, double-blind study; the sample size was 34 patients. The pre and postoperative outcomes, evaluated on the third (D3) and eighth day (D8), included inflam - tion, pain and oral aperture, as well as the need for analgesics. One group received bromelain 150mg per day for three days and 100mg on days 4 to 7. The other group received placebo in the same dosage. All outcomes wer - recorded quantitatively and analyzed with the Mann-Whitney U test for independent samples. Results: Although there were no statistically significant differences between the treatment groups, a trend towards less inflammation and improved oral aperture was observed in the group that received bromelain, compared to the group that received placebo. This trend can be attributed completely to random reasons, since there is no statistical difference in the results. Conclusions: Further studies are necessary to analyze different administration patterns and doses of bromelain for the use in the postoperative of impacted third molars

Nuevos modelos objetivos, precisos y reproducibles de evaluación y autoevaluación de competencias clínicas en Prótesis estomatológica fija para alumnos de Grado

Sin duda, el cambio de paradigma en los sistemas de evaluación constituye uno de principales planteamientos de la reforma del Grado en Odontología. El enfoque actual de la evaluación, que ha reemplazado los objetivos docentes por las competencias alcanzadas por el alumno, adquiere su máximo exponente en el caso de las disciplinas clínicas como la Prótesis Estomatológica, materia en la que el estudiante de Grado efectúa tratamientos a pacientes. Por otra parte, respondiendo a la necesidad de impulsar el aprendizaje autónomo, hay que destacar la importancia de facilitar herramientas al alumno, de modo que mediante procesos de autoevaluación, tome conciencia acerca de si es o no competente previo a acometer tratamientos clínicos. Por todo ello, precisamos determinar y evaluar con exactitud aquellos aspectos clínicos para los cuales el alumno debe alcanzar competencias profesionales. En definitiva, la evaluación por competencias posibilita acreditar los conocimientos y habilidades clínicas adquiridas por parte de los alumnos durante el desarrollo de las actividades prácticas. Dado que las competencias por sí mismas no pueden observarse, deben ser evaluadas por medio de evidencias; entendiendo este concepto como las pruebas que demuestran que se ha alcanzado o no un requerimiento, una competencia (en nuestro caso, clínica) o un resultado de aprendizaje (pre-clínico). Tan sólo conociendo las competencias clínicas que el alumno debe reunir, y diseñando un método adecuado para evaluarlas, estaremos en disposición de garantizar una formación nuclear sobre los aspectos más esenciales de la Odontología, concretamente en el campo de la Prótesis fija. Por tanto, con este proyecto pretendemos estratificar pormenorizadamente las competencias clínicas que conducen a la realización de los distintos tratamientos fijos de Prótesis Estomatológica. Asimismo, describimos cada competencia en base a un conjunto de ítems. Dando un paso más, hemos diseñado tests para evaluar dichos ítems en cada competencia. Se ha establecido además el peso que ejerce cada ítem en la puntuación final. Se ha acordado también una sistemática de aplicación de dichos tests, especificando qué profesores intervendrán en la evaluación, en qué momento se realizará, qué intervalo de tiempo se recomienda previo a una nueva evaluación de una misma competencia, etc. Con las rúbricas de evaluación de dichos tests, el alumno además podrá disponer desde un principio de la información acerca de los niveles de excelencia a exigir para cada ítem que compone una práctica determinada. En síntesis, con este proyecto pretendemos definir e implantar métodos objetivos y precisos para la evaluación y autoevaluación de las competencias clínicas esenciales en Prótesis fija. Una vez diseñado el proceso, se aplicará en prácticas mediante dispositivos móviles/tablets, para mayor agilidad y eficacia en su materialización. Con el planteamiento del que parte este proyecto, pretendemos que el protocolo de evaluación pueda vertebrar el examen de otras competencias en el terreno de la Prótesis Estomatológica, la Odontología general e, incluso, otras disciplinas de las Ciencias de la Salud

Vertical misfit of laser-sintered and vacuum-cast implant-supported crown copings luted with definitive and temporary luting agents

Objectives. This study aimed to evaluate the vertical discrepancy of implant-supported crown structures constructed with vacuum-casting and Direct Metal Laser Sintering (DMLS) technologies, and luted with different cement types. Study D esign. Crown copings were fabricated using: (1) direct metal laser sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Ti (CT). Frameworks were luted onto machined implant abutments under constant seating pressure. Each alloy group was randomly divided into 5 subgroups (n = 10 each) according to the cement system utilized: Subgroup 1 (KC) used resin-modified glass-ionomer Ketac Cem Plus; Subgroup 2 (PF) used Panavia F 2.0 dual-cure resin cement; Subgroup 3 (RXU) used RelyX Unicem 2 Automix self-adhesive dual-cure resin cement; Subgroup 4 (PIC) used acrylic/urethane-based temporary Premier Implant Cement; and Subgroup 5 (DT) used acrylic/urethane-based temporary DentoTemp cement. Vertical misfit was measured by scanning electron microscopy (SEM). Two-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, and cement type on vertical misfit. The statistical significance was set at ? = 0.05. Results. The alloy/manufacturing technique and the luting cement affected the vertical discrepancy (p < 0.001). For each cement type, LS samples exhibited the best fit (p < 0.01) whereas CC and CT frames were statistically similar. Within each alloy group, PF and RXU provided comparably greater discrepancies than KC, PIC, and DT, which showed no differences. Conclusions. Laser sintering may be an alternative to vacuum-casting of base metals to obtain passive-fitting implant-supported crown copings. The best marginal adaptation corresponded to laser sintered structures luted with glass-ionomer KC, or temporary PIC or DT cements. The highest discrepancies were recorded for Co-Cr and Ti cast frameworks bonded with PF or RXU resinous agents. All groups were within the clinically acceptable misfit range