Influence of Different Implants on the Biomechanical Behavior of a Tooth-Implant Fixed Partial Dentures: A Three-Dimensional Finite Element Analysis.

This study analyzed the biomechanical behavior of rigid and nonrigid tooth-implant supported fixed partial dentures. Different implants were used to observe the load distribution over teeth, implants, and adjacent bone using three-dimensional finite element analysis. A simulation of tooth loss of the first and second right molars was created with an implant placed in the second right molar and a prepared tooth with simulated periodontal ligament (PDL) in the second right premolar. Configurations of two types of implants and their respective abutments-external hexagon (EX) and Morse taper (MT)-were transformed into a 3D format. Metal-ceramic fixed partial dentures were constructed with rigid and nonrigid connections. Mesh generation and data processing were performed on the 3D finite element analysis (FEA) results. Static loading of 50 N (premolar) and 100 N (implant) were applied. When an EX implant was used, with a rigid or nonrigid connection, there was intrusion of the tooth in the distal direction with flexion of the periodontal ligament. Tooth intrusion did not occur when the MT implant was used independent of a rigid or nonrigid connection. The rigid or nonrigid connection resulted in a higher incidence of compressive forces at the cortical bone as well as stress in the abutment/pontic area, regardless of whether EX or MT implants were used. MT implants have a superior biomechanical performance in tooth-implant supported fixed partial dentures. This prevents intrusion of the tooth independent of the connection. Both types of implants studied caused a greater tendency of compressive forces at the crestal area.

Three-dimensional finite element analysis of glass fiber and cast metal posts with different alloys for reconstruction of teeth without ferrule.

The aim of this study was to evaluate different materials for restoration of teeth without ferrule by three-dimensional (3D) finite element analysis (FEA). Five models simulating the maxillary central incisor and surrounding bone were simulated according to the type of post: glass fibre post (GFP) or cast metal post (CMP) with different alloys such as gold (Au), silver-palladium (AgPd), copper-aluminum (CuAl) and nickel-chromium (NiCr). Models were designed using Invesalius and Rhinoceros. FEAs were made using FEMAP and NeiNastran, with an applied axial force of 100 N and oblique occlusal load at 45°. Stress distribution among groups was analysed by two-way analysis of variance (ANOVA), followed by post-hoc Tukey's test. The GFP showed the best stress distribution in the post, followed by CMP with Au, AgPd, CuAl and NiCr alloys, respectively (p < .001). No statistically significant difference in the stress distribution in teeth was found under application of axial load (p > .05). Under oblique load, the GFP generated the highest values of tension among the models, followed by the CMP with NiCr alloy than other models (p < .001). The use of GFP resulted in a lower stress concentration in the post, but increased stress in the tooth without ferrule. The CMP with NiCr alloy exhibited the highest stress distribution among other CMP. To avoid higher stress in teeth, alloys of Au, AgPd and CuAl, respectively, are recommended.

An harmonic smile resulted from the use of ceramic prosthesis with zirconia structure: a case report.

The rehabilitation of patients requiring an esthetic smile demands a multidisciplinary approach. This clinical report describes a treatment plan for recovery aesthetics' smile of anterior teeth using ceramic prosthesis with zirconia structure. Initially, a review of aesthetic parameters, diagnostic waxing, mock-up and provisional restorations was performed. A contextual assessment of aesthetic, proportion and shape of teeth was done to recreate a natural looking for teeth in consonance with the smile line. Subsequently, based on these parameters, fixed prostheses of the upper anterior teeth using ceramic restorations with zirconia infrastructures were performed. The use of ceramic restorations with zirconia structures associated with a careful treatment plan allows the professional to integrate esthetic and function for satisfactory clinical results. How to cite the article: Tavarez RR, Gonçalves LM, Dias AP, Dias AC, Malheiros AS, Silva AC, Bandeca MC. An harmonic smile resulted from the use of ceramic prosthesis with zirconia structure: A case report. J Int Oral Health 2014;6(3):90-2.

A limited and useful approach to determine proximal periodontal health / Un enfoque limitado y útil para determinar la salud proximal periodontal

Previous researchers have shown that there exists an interaction between gingival blood flow and gingival health. The purpose of this study was to compare the papillary blood flow at sites treated by a bridge with the blood flow at untreated sites. Twenty persons with resin-bonded fixed partial dentures were included in the study. The contralateral natural teeth of the site symmetrical to that of the restorations were used as controls. Blood flow was measured from the middle point of the papillae from both test and control sites by Laser Doppler Flowmetry (LDF). The plaque index, papillary bleeding index and probing depth measurements were recorded. There was a statistically significant difference between the test and control sites in papillary blood flow measurements and clinical indices (p < 0.05). Moreover, there was statistical significance between gingival blood flow measurements and papillary bleeding index in the experimental group (p < 0.05). In short, there exists an important relationship between resin-bonded fixed partial dentures and papillary blood flow. Although there were no correlations between LDF values and clinical parameters, it can be emphasized, within the limits of the study, that LDF readings have limited diagnostic value, at least when it comes to clinical performance of fixed prosthesis.

Investigadores anteriores han mostrado que existe una interacción entre el flujo de sangre gingival y la salud gingival. El propósito de este estudio fue comparar el flujo de sangre papilar en los sitios tratado por un puente, con el flujo de la sangre en los sitios no tratados. Veinte personas con prótesis dental parcial fija adherida con resina fueron incluidas en el estudio. Los dientes naturales contralaterales del sitio simétrico al de las restauraciones, se usaron como controles. El flujo de sangre se midió a partir del punto medio de las papilas de los sitios de prueba y de control, usando un medidor de flujo mediante Láser Doppler (LDF). Se registraron el índice de la placa, el índice de sangramiento papilar, y las mediciones para el examen de la profundidad. Hubo una diferencia estadísticamente significativa entre los sitios de la prueba y los de control en las mediciones del flujo de sangre papilar y los índices clínicos (p <0.05). Más aún: hubo una diferencia estadísticamente significativa entre las mediciones del flujo de sangre gingival y el índice de sangramiento papilar en el grupo del experimento (p <0.05). En resumen, existe una relación importante entre la prótesis dental parcial fija adherida con resina y el flujo de sangre papilar. Aunque no había ninguna correlación entre los valores de LDF y los parámetros clínicos, puede subrayarse - dentro de los límites del estudio - que las lecturas de LDF tienen un valor diagnóstico limitado, al menos cuando se trata del funcionamiento clínico de la prótesis fija.

Técnica Indirecta Para Reparación De Prótesis Parcial Fija Metal-Porcelana Relato Del Caso

Debido a la excelente estética y biocompatibilidad, las restauraciones con cerámicas son frecuentemente utilizadas en la práctica clínica diaria. A pesar de la evolución de las propiedades mecánicas de las cerámicas, existen casos extensos en que la indicación principal es el uso de coronas metalo-cerâmicas. Frente a la posibilidad de la fractura de esas prótesis, que ocurren del 5 y al 10% en 10 años de uso, existe la opción de reparar dichas prótesis, disminuyendo el costo y el tiempo operacional. Cuando la falla expone la porción metálica de la pieza, se indica una reparación indirecta, que consiste en la confección de una sobre estructura, cementada en la región previamente preparada, a partir de un modelo de trabajo. El objetivo de este trabajo fue demostrar una técnica de reparación indirecta de prótesis parciales fijas utilizando una sobre estructura metalo-cerámica.

Due the excellent esthetic and biocompatibility, metal ceramic restrations are frequently used at clinical daily practice. In sipte of the ceramic mechanical properties evolution, there are extensive cases that the primary indication are metalceramic crowns. Ahead of the possible fractures of these prosthesis, that happen from the 5 to 10% in 10 years of use, there are option to repair it, diminishing cost and chair time. When the failure expose the metal portion it indicates a indirect repair wich consist in manufacturing of a overlay, cemented on region that was previosly prepared, from a work cast. The aim of this study was demonstrate a indirect repair technique of fixed partial dentures using a metalceramic overlay.

All-ceramic and porcelain-fused-to-metal fixed partial dentures: a comparative study by 2D finite element analyses

All-ceramic fixed partial dentures (FPDs) have an esthetic approach for oral rehabilitation. However, metal-ceramic FPDs are best indicated in the posterior area where the follow-up studies found a lower failure rate. This 2D finite element study compared the stress distribution on 3-unit all-ceramic and metal-ceramic FPDs and identified the areas of major risk of failure. Three FPD models were designed: (1) metal-ceramic FPD; (2) All-ceramic FPD with the veneering porcelain on the occlusal and cervical surface of the abutment tooth; (3) All-ceramic FPD with the veneering porcelain only on the occlusal surface. A 100 N load was applied in an area of 0.5 mm² on the working cusps, following these simulations: (1) on the abutment teeth and the pontic; (2) only on the abutment teeth; and (3) only on the pontic. Relative to the maximum stress values found for the physiological load, all-ceramic FPD with only occlusal veneering porcelain produced the lowest stress value (220 MPa), followed by all-ceramic FPD with cervical veneering porcelain (322 MPa) and metal-ceramic FPD (387 MPa). The stress distribution of the load applied on the abutments was significantly better compared to the other two load simulations. The highest principal stress values were low and limited in a small area for the three types of models under this load. When the load was applied on the pontic, the highest stress values appeared on the connector areas between the abutments and pontic. In conclusion, the best stress values and distribution were found for the all-ceramic FPD with the veneering porcelain only on the occlusal surface. However, in under clinical conditions, fatigue conditions and restoration defects must be considered.