Characterization of Microstructure, Optical Properties, and Mechanical Behavior of a Temporary 3D Printing Resin: Impact of Post-Curing Time.

The present study aimed to characterize the microstructure of a temporary 3D printing polymer-based composite material (Resilab Temp), evaluating its optical properties and mechanical behavior according to different post-curing times. For the analysis of the surface microstructure and establishment of the best printing pattern, samples in bar format following ISO 4049 (25 × 10 × 3 mm) were designed in CAD software (Rhinoceros 6.0), printed on a W3D printer (Wilcos), and light-cured in Anycubic Photon for different lengths of time (no post-curing, 16 min, 32 min, and 60 min). For the structural characterization, analyses were carried out using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The mechanical behavior of this polymer-based composite material was determined based on flexural strength tests and Knoop microhardness. Color and translucency analysis were performed using a spectrophotometer (VITA Easy Shade Advanced 4.0), which was then evaluated in CIELab, using gray, black, and white backgrounds. All analyses were performed immediately after making the samples and repeated after thermal aging over two thousand cycles (5-55 °C). The results obtained were statistically analyzed with a significance level of 5%. FT-IR analysis showed about a 46% degree of conversion on the surface and 37% in the center of the resin sample. The flexural strength was higher for the groups polymerized for 32 min and 1 h, while the Knoop microhardness did not show a statistical difference between the groups. Color and translucency analysis also did not show statistical differences between groups. According to all of the analyses carried out in this study, for the evaluated material, a post-polymerization time of 1 h should be suggested to improve the mechanical performance of 3D-printed devices.

Targeting bonding protocols to increase the bond between acrylic resin or 3D printed denture bases and prefabricated or 3D printed denture teeth.

STATEMENT OF PROBLEM: The difference in chemical composition between denture base resin and denture teeth requires the development of bonding protocols that increase the union between the materials. PURPOSE: The purpose of this in vitro study was to evaluate the impact of different bonding protocols on the bond between heat-polymerized and 3-dimensionally (3D) printed acrylic resin denture bases and acrylic resin prefabricated and 3D printed artificial teeth. MATERIAL AND METHODS: Four types of artificial teeth were evaluated: prefabricated acrylic resin (VITA MFT) and 3D printed (Cosmos TEMP, PRIZMA 3D Bio Denture, and PrintaX AA Temp) bonded to 20×24-mm cylinders of heat-polymerized (VipiWave) and 3D printed (Cosmos Denture, PRIZMA 3D Bio Denture, and PrintaX BB Base) denture bases. Three bonding protocols were tested (n=20): mechanical retention with perforation + monomer (PT1), mechanical retention with perforation + airborne-particle abrasion with 50-µm aluminum oxide + monomer (PT2), and mechanical retention with perforation + Palabond (PT3). Half of the specimens in each group received 10 000 thermocycles and were then subjected to the bonding test at a crosshead speed of 1 mm/minute. The failure type was analyzed and scanning electron micrographs made. Additionally, surface roughness (Ra) and wettability (degree) were analyzed (n=15). ANOVA was used to evaluate the effect of the bonding protocol, and the Student t test was applied to compare the experimental groups with the control (α=.05). For type of failure, a descriptive analysis was carried out using absolute and relative frequency. The Kruskal-Wallis test was used to evaluate the surface changes (α=.05). RESULTS: Among the protocols, PT3 with in Yller and PT2 with Prizma had the highest bond strengths of the heat-polymerized denture base and 3D printed teeth (P<.05). When comparing the experimental groups with the control, PT3 and PT2 had greater union with the 3D printed denture base + 3D printed teeth (in Yller), with no difference from the heat-polymerized denture base + prefabricated teeth in acrylic resin. The treatment of the 3D printed tooth surfaces affected the surface roughness of Prizma (P<.001) and wettability (P<.001). CONCLUSIONS: To increase the bond between Yller 3D printed denture base + 3D printed teeth, a bonding protocol including mechanical retention with perforation + Palabond or mechanical retention with perforation + airborne-particle abrasion with aluminum oxide + monomer is indicated. For the other materials tested, further bonding protocols need to be investigated.

Is scanning under rubber dam isolation a feasible approach for the execution of indirect restorations? / O escaneamento sob isolamento absoluto é uma técnica viável para execução de restaurações indiretas?

Objective: The aim of the study was to report the aplicability of intraoral scanning while rubber dam isolation is in place. Material and Methods: Female patient, 50 years old, required restorative procedures on teeth 35 and 37. An intraoral scan was initially performed on both arches. Isolation was carried out from 33 to 37, tooth preparation and immediate dentin sealing were carried out. A new scan with the rubber dam in place was performed and a CAD/CAM lithium disilicate hybrid block was digitally designed, milled, crystallized and cemented under the tooth surface with the rubber dam still in position. After completing this stage, the rubber dam was removed, the occlusion was verified, presenting excellent aesthetic and functional results. Results: The absolute isolation process used in the present study works as an excellent device for gingival retraction. Conclusion: The absolute isolation can be recommended in clinical activities of intraoral scanning favoring the quality of the final result of treatments (AU)

Objetivo: O objetivo do estudo foi relatar a aplicabilidade do escaneamento intraoral sob isolamento absoluto. Material e Métodos: Paciente do sexo feminino, 50 anos, necessitou de procedimentos restauradores nos dentes 35 e 37. Uma varredura intraoral foi inicialmente realizada em ambos os arcos. O isolamento absoluto foi feito de 33 a 37, permitindo a realização do preparo dentário e selamento imediato da dentina. Um novo escaneamento com o dique de borracha colocado foi realizado e um bloco híbrido de dissilicato de lítio CAD/CAM foi projetado digitalmente, fresado, cristalizado e cimentado sob a superfície dentária ainda com o dique de borracha em posição. Após a finalização dessa etapa, o dique de borracha foi removido, a oclusão foi verificada apresentando ótimos resultados estéticos e funcionais. Resultados: O isolamento absoluto utilizado no presente estudo funciona como um excelente dispositivo para retração gengival. Conclusão: O isolamento absoluto pode ser recomendado em atividades clínicas de escaneamento intraoral favorecendo a qualidade do resultado final dos tratamentos (AU)

Assessment of Subgingival Biofilm and its Relationship with the Status of Tumors in a Population with Breast Cancer

This study aimed to compare the subgingival microbiota of subjects with and without breast cancer (BC). Patients with BC (Group 1; n= 50) and without BC (Group 2; n=50) with periodontitis (A) and without periodontitis (B). The study was conducted in two phases (P1 and P2). One biofilm sample was collected from each subject and analyzed by DNA-DNA Hybridization (Checkerboard DNA-DNA). The relative abundance of the subgingival microbiota differed between the Case and Control groups. However, some species were higher in patients in the Case than in Control subjects and differed between the groups in both phases. Composition of the subgingival microbial community according to the Socransky complex was related to periodontal disease, followed by clinical attachment of level (CAL ≥4mm), age, and tooth loss, which were found to be abundant in Cases when compared with controls. Patients with Tumor Grade II and III had a higher prevalence of tooth loss and CAL≥4mm. It was concluded that in individuals with BC, the sub-gingival microbiota exhibited atypical changes, but they developed periodontal disease.

El objetivo de este estudio fue comparar la microbiota subgingival de sujetos con y sin cáncer de mama (CM). Pacientes con CM (Grupo 1; n= 50) y sin CM (Grupo 2; n=50) con periodontitis (A) y sin periodontitis (B). El estudio se realizó en das fases (P1 y P2). Se recogió una muestra de biopelícula de cada sujeto y se analizó mediante hibridación ADN-ADN (tablero de ajedrez ADN-ADN). La abundancia relativa de la microbiota subgingival difirió entre los grupos de Caso y Control. Sin embargo, algunas especies fueron más altas en los pacientes del Caso que en los sujetos del Control y difirieron entre los grupos en ambas fases. La composición de la comunidad microbiana subgingival según el complejo de Socransky se relacionó con la enfermedad periodontal, seguida por el nivel de inserción clínica (CAL≥4mm), la edad y la pérdida de dientes, que se mostró abundante en los casos en comparación con los controles. Los pacientes con Tumor Grado II y III tuvieron mayor prevalencia de pérdida dental y CAL≥4mm. Se concluyó que en individuos con CM la microbiota subgingival presentó cambios atípicos, pero sin embargo, desarrollaron enfermedad periodontal.

Effect of Finishing Protocols on the Surface Roughness and Fatigue Strength of a High-Translucent Zirconia.

Purpose: In case of need for esthetical improvement of zirconia restorations, an individualization using extrinsic staining can be applied. This study aimed to evaluate the surface roughness and fatigue strength (survival) of high-translucency zirconia (3Y-TZP, YZ®HT, Vita Zanhfabrik) with extrinsic characterization and/or glaze. Methods: Sixty (60) zirconia discs (12 × 1.2 mm) were obtained, sintered, and randomly distributed among three groups (n = 20) according to the surface finishing protocol: C (control), C + G (extrinsic characterization followed by a glaze layer), and G (glaze layer). The surface roughness (Ra) was analyzed with a contact profilometer. Subsequently, the specimens were subjected to a fatigue load profile starting at 120 N during 20,000 cycles at 4 Hz frequency, with a 5% increase at each step until failure. The failed specimens were evaluated under a stereomicroscope. Surface roughness analysis was evaluated by using one-way ANOVA and post hoc Tukey tests (95%); while fatigue survival probability was analyzed with Kaplan-Meier and Mantel-Cox (log- rank, 95%). Results: One-way ANOVA revealed that surface roughness was affected by the finishing protocol, where C + G showed the highest mean value (0.46 ± 0.18 µm)A followed by G (0.30 ± 0.10 µm)B, and C (0.19 ± 0.02 µm)C. While for fatigue strength, the G protocol presented a higher mean value (243.00, and 222.36-263.63)A, followed by C + G (192.75 and 186.61-198.88)B and C (172.50 and 159.43-185.56)C. Conclusion: Surface finishing protocols modify the surface roughness and fatigue strength of high-translucent zirconia. Regardless of the surface roughness, both glazing protocols improved the ceramic fatigue strength, favoring the restoration's long-term survival.

Injectable Composite Resin Technique: An Alternative for Anterior Esthetic Restorations - Case Report / Técnica de Resina Compuesta Inyectable: Una Alternativa para Restauraciones Estéticas Anteriores - Reporte de Caso

This article aims to describe a clinical case of the use of the injectable restorative technique with composite resin in a patient with an esthetic complaint in the anterior teeth. Producing direct restorations in anterior teeth when performed with composite resin demands a long clinical time. Results often depend on the operator's ability to reproduce proper form, function, and esthetics. Lately, the versatility of composite resins has increased. As this material evolved, new techniques were introduced to simplify the restorative process and save time. The restorative technique with injectable fluid composite resin, in addition to delivering faster and with a certain ease, is capable of increasing the predictability of treatment results. However, it is known that flowable resins have lower wear resistance and color stability compared to conventional resins. Thus, a version of this material with a higher filler content in its composition was introduced to the market, to improve wear resistance and gloss retention. Long-term studies evaluating the use of low-viscosity resins are needed. The injectable technique can accurately reproduce the morphology obtained in the wax-up of the case, generating a satisfactory esthetic and functional result. Despite simplifying the fabrication of restorations when compared to the conventional technique, it is still necessary for the operator to have some experience and aptitude. The clinical time for the production of restorations has been considerably reduced. The material showed good flow, shine, and polish in the immediate result. However, the finishing and polishing of the restorations required a longer clinical period than usual and in the short- term follow-up, flaws in the gingival margins and a new finishing and polishing procedure were necessary. Therefore, the technique described in this article can be considered a restorative alternative, but it is still not able to replace the tradit ional method of making previous esthetic restorations.

Este artículo tiene como objetivo describir un caso clínico del uso de la técnica restauradora inyectable con resina compuesta en un paciente con una queja estética en los dientes anteriores. Producir restauraciones directas en dientes anteriores cuando se realizan con resina compuesta demanda un largo tiempo clínico. Los resultados a menudo dependen de la capacidad del operador para reproducir la forma, la función y la estética adecuadas. Últimamente, la versatilidad de las resinas compuestas ha aumentado. A medida que este material evolucionó, se introdujeron nuevas técnicas para simplificar el proceso de restauración y ahorrar tiempo. La técnica restauradora con resina compuesta fluida inyectable, además de una entrega más rápida y segura, es capaz de aumentar la previsibilidad de los resultados del tratamiento. Sin embargo, se sabe que las resinas fluidas tienen menor resistencia al desgaste y estabilidad del color en comparación con las resinas convencionales. Así, se introdujo en el mercado una versión de este material con un mayor contenido de relleno en su composición, con el objetivo de mejorar la resistencia al desgaste y la retención del brillo. Se necesitan estudios a largo plazo que evalúen el uso de resinas de baja viscosidad. La técnica inyectable es capaz de reproducir fielmente la morfología obtenida en el encerado del caso, generando un resultado estético y funcional satisfactorio. A pesar de simplificar la fabricación de restauraciones en comparación con la técnica convencional, todavía es necesario que el operador tenga cierta experiencia y aptitud. El tiempo clínico para la producción de restauraciones se ha reducido considerablemente. El material mostró buena fluidez, brillo y pulido en el resultado inmediato. Sin embargo, el acabado y pulido de las restauraciones requirió de un período de tiempo clínico más largo de lo habitual y en el seguimiento a corto plazo, fueron necesarios defectos en los márgenes gingivales y un nuevo procedimiento de acabado y pulido. Por lo tanto, la técnica descrita en este artículo puede considerarse una alternativa restauradora, pero aún no es capaz de reemplazar el método tradicional de realizar restauraciones estéticas previas.

Current Insights on Neoplasms and Adequate Dental Care for Patients with Oral Cancer / Actualización sobre Neoplasmas y su Correcta Atención Odontológica en Pacientes con Cancer Oral

The present study aimed to review the literature on the main complications of antineoplastic therapies and the degree of knowledge of dental surgeons about these complications. A bibliographic search was conducted in the main health databases PUBMED (www.pubmed.gov) and Scholar Google (www.scholar.google.com.br), in which studies published from 1987 to 2023 were collected. Laboratory studies, case reports, systematic and literature reviews, which were developed in living individuals, about the main neoplastic genes and their relationship with the cells of individuals affected by neoplasms in the head and neck region, and studies on the care with this group of patients, were included. Therefore, articles that did not deal with neoplasm and the main complications of antineoplastic therapies were excluded. Neoplasm is a clonal disorder, caused by mutations, resulting from changes in the genetic structure of cells. Each healthy cell has instructions on how to grow and divi de. In the presence of any error in these instructions (mutation), it can result in a diseased cell that, when proliferating, may cause a tumor. Countless knowledge has been accumulated over the years on the main characteristics of neoplasms, whether they are cancer cell biology, carcinogenesis mechanism, neoplasms of the maxillofacial system and sequels of antineoplastic treatments. In this context, methods have been developed that offer a better quality of life for patients diagnosed with this pathology, as well as preventive vaccine models that may, in the not too distant future, contribute to this goal to be successfully achieved.

El presente estudio tuvo como objetivo revisar la literatura sobre las principales complicaciones de las terapias antineoplásicas y el grado de conocimiento de los odontólogos sobre este abordaje. Se realizó una búsqueda bibliográfica en las principales bases de datos de salud PUBMED (www.pubmed.gov) y Scholar Google (www.scholar.google.com.br), en la que se recopilaron estudios publicados entre 1987 y 2023. Fueron incluidos estudios de laboratorio, relatos de casos, revisiones de la literatura y revisiones sistemáticas, desarrolladas en individuos vivos, que incluyeran los principales genes neoplásicos y su relación con las células de individuos afectados por neoplasias en la cabeza y el cuello. También, se tuvieron en cuenta estudios relacionados con la atención a este grupo de pacientes. La neoplasia es un trastorno clonal, causado por mutaciones, como resultado de cambios en la estructura genética de las células. Cada célula sana tiene instrucciones sobre cómo crecer y dividirse. En presencia de cualquier error en estas instrucciones (mutación), puede provocar una célula alterada que, al proliferar, puede causar un tumor. Se han acumulado innumerables conocimientos a lo largo de los años sobre las principales características de las neoplasias, ya sea sobre biología de células cancerosas, el mecanismo de la carcinogénesis, la neoplasias del sistema maxilofacial y las diferentes secuelas de tratamientos antineoplásicos. En este contexto, se han desarrollado métodos que ofrecen una mejor calidad de vida para los pacientes diagnosticados con esta patología, así como modelos de vacunas preventivas que, en un futuro no muy lejano, pueden contribuir a alcanzar este objetivo con éxito.

Interface adhesion on layered zirconia: Effects of the veneering ceramic material and veneering technique.

PURPOSE: To evaluate the effect of different veneering ceramics and veneering techniques on the bond strength to zirconia. MATERIALS AND METHODS: 3Y-TZP zirconia blocks were sliced into 60 slabs, polished, and sintered. Each slab received one ceramic cylinder (Ø = 3.4 mm, 5 mm-high), according to the veneering ceramic type (feldspathic-FEL or lithium disilicate-based-LD) and the veneering technique (file-splitting with resin-based luting agent-RC, file-splitting with fusion ceramic-FC, or heat-pressing-HT), which resulted in six groups: FEL-RC, FEL-FC, FEL-HT, LD-RC, LD-FC, LD-HT. After preparation, the samples were immersed in distilled water for 24 h before the shear bond strength (SBS) test. The failure modes were classified as adhesive, predominantly adhesive, or cohesive. Representative failure mode images were taken in a Scanning Electron Microscope. The SBS data were analyzed by two-way ANOVA and Tukey's test. RESULTS: Both type of veneering ceramic and technique affected the bond strength. FC led to the highest SBS values. RC and HP provided similar results when compared within each veneering ceramic. Lithium disilicate achieved lower bond strength than feldspathic ceramic when the heat-pressing technique was applied. The most frequent failure modes were predominantly adhesive and adhesive for FEL and LD, respectively. CONCLUSION: File-splitting with fusion ceramic provided the highest adhesion to zirconia when feldspathic or lithium disilicate-based ceramics were used. The heat-pressing technique for veneering with lithium disilicate significantly decreased the bond strength when compared to the feldspathic ceramic.

Preheated Composite as an Alternative for Bonding Feldspathic and Hybrid Ceramics: A Microshear Bond Strength Study.

PURPOSE: To evaluate the bond strength between alternative or conventional luting agents and indirect restorative materials. MATERIALS AND METHODS: Blocks of a polymer-infiltrated ceramic network (PICN, Vita Enamic) and a feldspathic ceramic (FEL, Vita Mark II) were sliced and divided according to the luting agent: resin cement (PICN-RC, FEL-RC), flowable composite (PICN-FC, FEL-FC), or preheated composite (PICN-PH, FEL-PH). The ceramic surfaces were polished, etched with 5% hydrofluoric acid for 60 s, and then a silane layer was applied. Cylinders of the luting agents were built up on the ceramic surfaces. In half the samples, the microshear bond strength (µSBS) was tested after 24 h (baseline). The other half was tested after 5000 thermocycles (5°C-55°C) (aging). The failure modes were determined using a stereomicroscope, and the ceramic surfaces were analyzed using a scanning electron microscope. Data were statistically analyzed with two-way ANOVA. RESULTS: Thermocycling reduced the bond strength values of all experimental groups. Regarding FEL, the preheated composite obtained the highest results. Resin cement showed results similar to the flowable composite at baseline and after aging. The highest results of PICN were obtained from the preheated composite followed by resin cement and flowable composite. Significant differences among the three luting agents were observed before and after aging. The most frequent failures among the experimental groups were adhesive and cohesive in the ceramic. CONCLUSION: Bond strength results indicate that the preheated composite can be an alternative for adhesive cementation when applied on the tested feldspathic ceramic or PICN.

Effect of Antirotational Two-Piece Titanium Base on the Vertical Misfit, Fatigue Behavior, Stress Concentration, and Fracture Load of Implant-Supported Zirconia Crowns.

This study investigated the effects of antirotational titanium bases on the mechanical behavior of CAD/CAM titanium bases used for implant-supported prostheses. The aim was to assess the impact on the marginal fit, fatigue behavior, stress concentration, and fracture load of implant-supported CAD/CAM zirconia crowns. Forty titanium implants were divided into two groups: those with antirotational titanium bases (ARs) and those with rotational titanium bases (RTs). Torque loosening and vertical misfit were evaluated before and after cyclic fatigue testing (200 N, 2 Hz, 2 × 106 cycles). Fracture resistance was assessed using a universal testing machine (1 mm/min, 1000 kgf), and failed specimens were examined with microscopy. Three-dimensional models were created, and FEA was used to calculate stress. Statistical analysis was performed on the in vitro test data using two-way analysis of variance and Tukey's test (α = 0.5). Results show that the presence of an antirotational feature between the implant and titanium base reduced preload loss and stress concentration compared to rotational titanium bases. However, there were no differences in vertical misfit and resistance to compressive load.

Biomechanical Behavior Evaluation of a Mandibular Full-Arch Implant-Supported Prosthesis on ZrO2 and TiO2 Monotype Dental Implants / Evaluación del Comportamiento Biomecánico de una Prótesis Implante Soportada de Arcada Completa Mandibular sobre Implantes Dentales Monotipos de ZrO 2 y TiO

This in silico study aimed to evaluate the biomechanical behavior of a full-arch implant-supported prosthesis on titanium and zirconia monotype implants. A 3D mandible containing 1.0 mm thick cortical and cancellous bone was modeled. Four dental implants (3.3 x 10 mm) were inserted into the jaw model in each model. The implants consisted of Titanium (Ti-S group) and Zirconia Monotype/one-piece (Zr-S group). Fixed full-arch implant-supported prostheses were cemented onto the implant. The models were exported to the analysis software and divided into meshes composed of nodes and tetrahedral elements. All materials were considered isotropic, elastic, and homogeneous. Therefore, all contacts were considered bonded, the mandible model was fixed in all directions, applying a static structural axial load of 300 N on the bottom of the fossa of the left mola r teeth. Microstrain and von-Mises stress (MPa) were adopted as failure criteria. Comparable stress and strain values were shown in the peri-implant bone for both groups. However, the Ti-S group presented a lower stress value (1,155.8 MPa) than the Zr-S group (1,334.2 MPa). Regarding bone tissues, the Ti-S group presented 612 µε and the Zr-S group presented 254 µε. The highest strain peak was observed in bone tissues around the implant closer to the load for both groups. Evaluating monotype zirconia and titanium implants, it is suggested that the greater the rigidity of the implant, the greater the concentration of internal stre sses and the less dissipation to the surrounding tissues. Therefore, monotype ceramic implants composed of yttrium-stabilized tetragonal polycrystalline zirconia may be a viable alternative to titanium implants for full-arch prostheses.

El objetivo de este estudio in silico fue evaluar el comportamiento biomecánico de una prótesis implanto soportada de arcada completa sobre implantes monotipo de titanio y zirconia. Se modeló una mandíbula en 3D que contenía tejido óseo cortical y esponjoso de 1,0 mm de espesor. En cada modelo, se insertaron cuatro implantes dentales (3,3 x 10 mm) en el modelo de mandíbula. Los implantes consistieron en Monotipo de Titanio y Zirconia. Sobre el implante se cementaron prótesis implanto soportadas de arcada completa fija. Los modelos se exportaron al software de análisis y se dividieron en mallas compuestas por nodos y elementos tetraédricos. Todos los materiales se consideraron isotrópicos, elásticos y homogéneos. Por lo tanto, todos los contactos se consideraron cementados, el modelo mandibular se fijó en todas las direcciones, aplicando una carga vertical estructural estática de 300 N en el fondo de la fosa de los dientes molares izquierdos. Se seleccionaron la microesfuerzo y la tensión de Von-Mises (MPa) como criterios de falla. Se mostraron valores de tensión y deformación comparables en el hueso periimplantario para ambos grupos. Sin embargo, el grupo Ti-S presentó un valor de estrés menor (1.155,8 MPa) que el grupo Zr-S (1.334,2 MPa). En cuanto a los tejidos óseos, el grupo Ti-S presentó 612 µε y el grupo Zr-S presentó 254 µε. La mayor concentración de deformación en el tejido óseo se observó en los tejidos alrededor del implante más cerca de la carga para ambos grupos. Al evaluar los implantes monotípicos de zirconia y titanio, se sugiere que cuanto mayor sea la rigidez del implante, mayor será la concentración de tensiones internas y menor la disipación a los tejidos circundantes. Por lo tanto, los implantes cerámicos monotipo compuestos de zirconia policristalina tetragonal estabilizada con itrio pueden ser una alternativa viable a los implantes de titanio para prótesis de arcada completa.

Knowledge, Attitudes, and Practices on New Treatment Modalities for Temporomandibular Dysfunctions and Orofacial Pain / Conocimientos, Actitudes y Prácticas sobre Nuevas Nodalidades de Tratamiento de las Disfunciones Tempomanibulares y el Dolor Orofacial

The present study proposed to describe, through a literature review, the use of new therapeutic management which allows for offering a better quality of life to individuals affected by these pathologies. A bibliographic search was conducted in the main health databases PUBMED (www.pubmed.gov) and Scholar Google (www.scholar.google.com.br), in which studies published from 1987 to 2023 were collected. In the first stage, the list of retrieved articles was examined by reading the titles and abstracts. In the second stage, the studies were selected by reading the full contents. Two authors (JDMM and DAQ) performed stages 1 and 2. Experimental, clinical, case-control, randomized controlled, and laboratory cohort studies, case reports, systematic reviews, and literature reviews, which were developed in living individuals, were included. Therefore, articles that did not deal with the subject in question, letters to the editor, opinion articles, duplicated literature in databases, and literature that did not address the variables under study, we re excluded. Contemporary dentistry uses alternative treatments capable of improving the patient's condition since a cure is not always possible. Therefore, the possibility of improving the quality of life becomes an important point to be reached. Evidence-based healthcare has made great advances in recent decades, especially in the areas of orofacial pain, TMD, and occlusion, especially related to orthodontic, prosthetic, and restorative care.

En el presente estudio se propuso describir, a través de una revisión bibliográfica, el uso de nuevos manejos terapéuticos que permitan brindar una mejor calidad de vida a los individuos afectados por estas patologías. Se realizó una búsqueda bibliográfica en las principales bases de datos de salud PUBMED (www.pubmed.gov) y Scholar Google (www.scholar.google.com.br), en las que se recopilaron estudios publicados entre 1987 y 2023. En la primera etapa, se examinó la lista de artículos recuperados mediante la lectura de los títulos y resúmenes. En la segunda etapa, los estudios fueron seleccionados mediante la lectura del contenido completo. Dos autores (JDMM y DAQ) realizaron las etapas 1 y 2. Se incluyeron estudios de cohortes experimentales, clínicos, de casos y controles, controlados aleatorios y de laboratorio, informes de casos, revisiones sistemáticas y revisiones de la literatura, que se desarrollaron en individuos vivos. Por lo tanto, se excluyeron artículos que no trataran el tema en cuestión, cartas al editor, artículos de opinión, literatura duplicada en bases de datos y literatura que no abordara las variables en estudio. La odontología contemporánea utiliza tratamientos alternativos capaces de mejorar el estado del paciente, ya que no siempre es posible la curación. Por lo tanto, la posibilidad de mejorar la calidad de vida se convierte en un objetivo importante. La atención médica basada en la evidencia ha logrado grandes avances en las últimas décadas, especialmente en las áreas de dolor orofacial, TMD y oclusión, especialmente en relación con la atención de ortodoncia, prótesis y restauración.

Effect of staining layer on roughness after progressive wear of monolithic ceramics.

PURPOSE: The aim of this study was to evaluate staining layer behavior applied to high-translucency zirconia (YZHT), feldspathic ceramics (FD), and zirconia-reinforced lithium silicate (ZLS) surfaces against different antagonists. METHODS AND MATERIALS: Monolithic ceramic discs (n = 120) (ø 12 mm; thickness, 1.2 mm; ISO 6872) were obtained, 30 from YZHT and FD, and 60 from ZLS CAD/CAM blocks (staining layer applied before or after the crystallization procedure). The specimens were divided into 12 subgroups (n = 10) according to the antagonists: steatite, polymer-infiltrated ceramic, or zirconia. Mechanical cycling (1.5 × 104 cycles; 15 N; horizontal displacement, 6 mm; 1.7 Hz) and flexural strength tests (1 mm/min-1000 kg cell) were performed. The differences between final and initial roughnesses (Ra, Rz, and Rsm), the mass loss, and the flexural strength data were individually analyzed by two-way ANOVA and Tukey's test (α = 0.05). RESULTS: The roughnesses of all ceramics did not present a statistically significant difference before wear simulation: Ra (p = 0.3348), Rz (p = 0.5590), and Rsm (p = 0.5330). After the wear simulation, the Ra parameter was not affected by an interaction between ceramic and antagonist (p = 0.595). The Rz and Rsm parameters were affected only by the antagonist pistons (both, p = 0.000). The ceramics used in this study showed statistically significant differences in mass loss after the wear test (p < 0.0001). The additional firing (2 steps) of the ZLS2 led to a higher lost mass quantity. CONCLUSION: All ceramics presented similar initial roughnesses and similar roughnesses after the wear simulation. The zirconia antagonist showed better performance against ceramics with high crystalline content. CLINICAL SIGNIFICANCE: It is clear that restorative materials must be carefully selected by dental practitioners according to indications, properties, and antagonists. The steatite antagonist, that is, an enamel analog, showed better performance against vitreous ceramics, while the zirconia antagonist showed better performance against ceramics with high crystalline content. Wear affects the surface roughnesses of the ceramics. Additional firing for the staining of the zirconia-reinforced lithium silicate ceramic led to a greater loss of mass.

Resin cement coating reverts the machining damage on the flexural fatigue strength of lithium disilicate glass-ceramic.

This study evaluated the effect of resin cement coating with high and low viscosities on the flexural fatigue strength of machined lithium disilicate glass-ceramic. Discs (IPS e.max CAD; Ivoclar Vivadent) were prepared and divided according to the surface condition (machining [M]-CEREC inLab; and polishing [P]-laboratory procedures), resin cement coating (with or without), and cement viscosity (high [H] and low [L]). The ceramic bonding surface was etched/primed by a one-step primer application followed by resin cement application (Variolink N base + high or low viscosity catalyst; Ivoclar Vivadent). Biaxial flexural fatigue strength was evaluated on a piston-on-three-ball set by the step-test method (n = 15) (initial stress: 60 MPa; incremental steps: 20 MPa; 10,000 cycles/step, at 20 Hz). Weibull statistics were used for fatigue data. Contact angle, topographic, and fractographic analysis were also performed. Machining produced statistically lower contact angle than polishing and a significant detrimental effect on the fatigue behavior (σ0 M = 247.2 [246.9-268.3]; σ0 P = 337.4 [297.8-382.4]). Machined groups followed by resin cement coating (σ0 MH = 297.9 [276.0-321.5]; σ0 Ml = 301.2 [277.1-327.4]) behaved similarly to the polished and coated groups (σ0 PH = 342.0 [308.9-378.5]; σ0 PL = 357.3 [324.7-393.1]), irrespective of the cement viscosity. Therefore, cement coating has able to revert the detrimental effects of the machining on the fatigue strength of lithium disilicate glass-ceramic. High and low viscosity cements behaved similarly in the improvement of CAD-CAM lithium disilicate fatigue strength.

Effect of Resin Cement at Different Thicknesses on the Fatigue Shear Bond Strength to Leucite Ceramic.

OBJECTIVES: This in vitro study was performed to evaluate fatigue survival by shear test in the union of leucite-reinforced feldspathic ceramic using different cement thicknesses. MATERIALS AND METHODS: Leucite-reinforced glass ceramics blocks were sectioned in 2-mm thick slices where resin cylinders were cemented. The samples were distributed in two experimental groups (n = 20) according to the cement thickness (60 and 300 µm). The specimens of each group were submitted to the stepwise fatigue test in the mechanical cycling machine under shear stress state, with a frequency of 2 Hz, a step-size of 0.16 bar, starting with a load of 31 N (1.0 bar) and a lifetime of 20,000 cycles at each load step. RESULTS: The samples were analyzed in a stereomicroscope and scanning electron microscopy to determine the failure type. There is no significant difference between the mean values of shear bond strength according to both groups. Log-rank (p = 0.925) and Wilcoxon (p = 0.520) tests revealed a similar survival probability in both cement layer thicknesses according to the confidence interval (95%). The fracture analysis showed that the mixed failure was the most common failure type in the 300-µm thickness group (80%), while adhesive failure was predominant in the 60-µm thickness group (67%). The different cement thicknesses did not influence the leucite ceramic bonding in fatigue shear testing; however, the thicker cement layer increased the predominance of the ceramic material failure. CONCLUSION: The resin cement thicknesses bonded to leucite ceramic did not influence the long-term interfacial shear bond strength, although thicker cement layer increased the ceramic material cohesive failure. Regardless the cement layer thickness, the shear bond strength lifetime decreases under fatigue.

Silica infiltration on translucent zirconia restorations: Effects on the antagonist wear and survivability.

OBJECTIVE: To assess potential antagonist wear and survival probability of silica-infiltrated zirconia compared to glass-graded, glazed, and polished zirconia. METHODS: Table top restorations made of 3Y-TZP (3Y), 5Y-PSZ (5Y), and lithium disilicate (LD) were bonded onto epoxy resin preparations. Each zirconia was divided into five groups according to the surface treatment: polishing; glaze; polishing-glaze; glass infiltration; and silica infiltration. The LD restorations received a glaze layer. Specimens were subjected to sliding fatigue wear using a steatite antagonist (1.25 ×106 cycles, 200 N). The presence of cracks, fractures, and/or debonding was checked every one/third of the total number of cycles was completed. Roughness, microstructural, Scanning electron microscopy, wear and residual stress analyses were conducted. Kaplan-Meier, Mantel-Cox (log-rank) and ANOVA tests were performed for statistical analyses. RESULTS: The survival probability was different among the groups. Silica infiltration and polishing-glaze led to lower volume loss than glaze and glass-infiltration. Difference was observed for roughness among the zirconia and surface treatment, while lithium disilicate presented similar roughness compared to both glazed zirconia. Scanning electron microscopy revealed the removal of the surface treatment after sliding fatigue wear in all groups. Compressive stress was detected on 3Y surfaces, while tensile stress was observed on 5Y. SIGNIFICANCE: 3Y and 5Y zirconia behaved similarly regarding antagonist wear, presenting higher antagonist wear than the glass ceramic. Silica-infiltrated and polished-glazed zirconia produced lower antagonist volume loss than glazed and glass-infiltrated zirconia. Silica-infiltrated 3Y and lithium disilicate restorations were the only groups to show survival probabilities lower than 85%.

Influence of the Peek Abutments on Mechanical Behavior of the Internal Connections Single Implant.

The present study aimed to evaluate the biomechanical behavior of PEEK abutments with different heights on single titanium implants. To investigate the implant surface, different tests (scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction) were adopted. Herein, 20 implants received the 4.5 × 4.0 mm PEEK short abutment (SA) and 20 received the 4.5 × 5.5 mm PEEK long abutment (LA). The abutments were installed using dual-cure resin cement. To determine the fatigue test, two specimens from each group were submitted to the single load fracture test. For this, the samples were submitted to a compressive load of (0.5 mm/min; 30°) in a universal testing machine. For the fatigue test, the samples received 2,000,000 cycles (2 Hz; 30°). The number of cycles and the load test was analyzed by the reliability software SPSS statistics using Kaplan-Meier and Mantel-Cox tests (log-rank) (p < 0.05). The maximum load showed no statistically significant differences (p = 0.189) for the SA group (64.1 kgf) and the LA group (56.5 kgf). The study groups were statistically different regarding the number of cycles (p = 0.022) and fracture strength (p = 0.001). PEEK abutments can be indicated with caution for implant-supported rehabilitation and may be suitable as temporary rehabilitation.

Effect of Surface-Etching Treatment, Glaze, and the Antagonist on Roughness of a Hybrid Ceramic after Two-Body Wear.

Stains and glaze are effective procedures for achieving an aesthetic smoothness on indirect restorations. Thus, the effect of surface-etching treatments previous to the stain layer and the glaze application on the occlusal and antagonist wear of a hybrid ceramic were evaluated against different antagonists. Disc-shaped samples were prepared from polymer-infiltrated ceramic network (PICN) blocks. The specimens were divided into eight groups, according to the surface-etching treatment and glaze application: P (polished specimens); PG (polishing plus glaze); E (hydrofluoric acid etching plus stain); EG (acid etching plus stain plus glaze); A (aluminum oxide sandblasting plus stain); AG (sandblasting plus stain plus glaze); S (self-etching primer plus stain); SG (self-etching primer plus stain plus glaze). Half of the samples were subjected to a wear simulation with a steatite antagonist, and the other half was tested using a PICN antagonist. The test parameters were: 15 N, 1.7 Hz, 6 mm of horizontal sliding, 5000 cycles. The discs and the antagonists' masses were measured before and after the wear tests. The average roughness and spacing defects were evaluated. The etching treatment affected the surface and antagonist mass loss when tested against steatite. AG showed the highest mass loss. This influence was not detected when using the PICN antagonist. The glaze application after staining ensures a smoother surface and avoids antagonist wear.

Effect of Porcelain-to-Zirconia Ratio and Bonding Strategy on the Biaxial Flexural Strength and Weibull Characteristics of a Stress-Free Bilayer CAD/CAM Ceramic System.

PURPOSE: To evaluate the biaxial flexural strength of different porcelain-to-zirconia thickness ratios and bonding strategies of a stress-free bilayer CAD/CAM ceramic system. MATERIALS AND METHODS: A total of 60 zirconia discs (diameter: 15 mm; thickness: 0.3 or 0.5 mm; n = 30 for each thickness) were divided into six groups (n = 10 each) according to porcelain-to-zirconia ratio and bonding strategy: VM/Zr (control): zirconia discs veneered with a feldspathic ceramic (VM 9, Vita) in 0.9-mm and 0.7-mm thicknesses using a conventional hand-layering technique; VB/Zr-SBU: zirconia discs airborne particle-abraded with 50-µm Al2O3 particles followed by an MDP primer application (Single Bond Universal, 3M) and bonded to the porcelain with a resin cement (Panavia F 2.0, Kuraray); and VB/Zr-RC: zirconia discs airborne particle-abraded with 30-µm silica-coated Al2O3 particles and silanized and bonded to the porcelain with the same resin cement. Before cementation, the VB (Vitablocs II) discs were etched with 5% hydrofluoric acid (60 seconds), followed by silane application. The bilayers (thickness = 1.2 mm) were loaded with 750 g while light curing the resin cement. Two porcelain-to-zirconia thickness ratios were evaluated: 0.9: 0.3 mm and 0.7: 0.5 mm. All groups were subjected to 106 mechanical cycles, followed by a biaxial flexural test. Data (MPa) were subjected to two-way analysis of variance (ANOVA), Tukey test (5%), and Weibull analyses. RESULTS: Two-way ANOVA revealed that the factor porcelain-to-zirconia ratio (P = .0556) was not significant; however, the bonding strategy factor was statistically significant. Among the 0.5-mm zirconia groups, the VB/Zr-SBU group presented higher flexural strength (s) than the VM/Zr or VB/Zr-RC groups. Similar results were also found for the 0.3-mm zirconia groups, in which the VB/Zr-SBU group also presented higher strength than the others, which were similar in comparison (Tukey). The Weibull modulus was similar among the groups; however, the characteristic strength was significantly different (P = .000). CONCLUSION: The zirconia bonding strategy with 50-µm Al2O3 airborne-particle abrasion, followed by a primer application, increases the flexural strength of a stress-free bilayer CAD/CAM ceramic system.

Influence of Abutment Design on Biomechanical Behavior to Support a Screw-Retained 3-Unit Fixed Partial Denture.

This study aimed to evaluate the biomechanical behavior of Morse taper implants using different abutments (CMN abutment [(CMN Group] and miniconical abutments [MC Group]), indicated to support a screw-retained 3-unit fixed partial denture. For the in vitro test, polyurethane blocks were fabricated for both groups (n = 10) and received three implants in the "offset" configuration and their respective abutments (CMN or MC) with a 3-unit fixed partial denture. Four strain gauges were bonded to the surface of each block. For the finite element analysis, 3D models of both groups were created and exported to the analysis software to perform static structural analysis. All structures were considered homogeneous, isotropic, and elastic. The contacts were considered non-linear with a friction coefficient of 0.3 between metallic structures and considered bonded between the implant and substrate. An axial load of 300 N was applied in three points (A, B, and C) for both methods. The microstrain and the maximum principal stress were considered as analysis criteria. The obtained data were submitted to the Mann-Whitney, Kruskal-Wallis, and Dunn's multiple comparison test (α = 5%). The results obtained by strain gauge showed no statistical difference (p = 0.879) between the CMN (645.3 ± 309.2 µÎµ) and MC (639.3 ± 278.8 µÎµ) and allowed the validation of computational models with a difference of 6.3% and 6.4% for the microstrains in the CMN and MC groups, respectively. Similarly, the results presented by the computational models showed no statistical difference (p = 0.932) for the CMN (605.1 ± 358.6 µÎµ) and MC (598.7 ± 357.9 µÎµ) groups. The study concluded that under favorable conditions the use of CMN or MP abutments to support a fixed partial denture can be indicated.