Group 2 ITI Consensus Report: Prosthodontics and implant dentistry.

OBJECTIVES: Working Group 2 was convened to address topics relevant to prosthodontics and dental implants. Systematic reviews were developed according to focused questions addressing (a) the number of implants required to support fixed full-arch restorations, (b) the influence of intentionally tilted implants compared to axial positioned implants when supporting fixed dental prostheses (FDPs), (c) implant placement and loading protocols, (d) zirconia dental implants, (e) zirconia and metal ceramic implant supported single crowns and (f) zirconia and metal ceramic implant supported FDPs. MATERIALS AND METHODS: Group 2 considered and discussed information gathered in six systematic reviews. Group participants discussed statements developed by the authors and developed consensus. The group developed and found consensus for clinical recommendations based on both the statements and the experience of the group. The consensus statements and clinical recommendations were presented to the plenary (gathering of all conference attendees) and discussed. Final versions were developed after consensus was reached. RESULTS: A total of 27 consensus statements were developed from the systematic reviews. Additionally, the group developed 24 clinical recommendations based on the combined expertise of the participants and the developed consensus statements. CONCLUSIONS: The literature supports the use of various implant numbers to support full-arch fixed prostheses. The use of intentionally tilted dental implants is indicated when appropriate conditions exist. Implant placement and loading protocols should be considered together when planning and treating patients. One-piece zirconia dental implants can be recommended when appropriate clinical conditions exist although two-piece zirconia implants should be used with caution as a result of insufficient data. Clinical performance of zirconia and metal ceramic single implant supported crowns is similar and each demonstrates significant, though different, complications. Zirconia ceramic FDPs are less reliable than metal ceramic. Implant supported monolithic zirconia prostheses may be a future option with more supporting evidence.

Influence of repeated firings on marginal, axial, axio-occlusal, and occlusal fit of metal-ceramic restorations fabricated with different techniques.

STATEMENT OF PROBLEM: Ill-fitting restorations can jeopardize dental, periodontal, and systemic health. Repeated ceramic firing may influence the fitting accuracy of restorations, but scientific information regarding this issue is lacking. PURPOSE: The purpose of this in vitro study was to assess and compare the influence of repeated firings on the marginal, axial, axio-occlusal, and occlusal fit of metal-ceramic 3-unit fixed partial dentures (FPDs) manufactured with different framework methods, including casting, fully sintered hard alloy milling (FHAM), presintered soft alloy milling (PSAM), and selective laser sintering (SLS). MATERIAL AND METHODS: A total of 60 Co-Cr metal frameworks for 3-unit FPDs were fabricated with 3 different computer-aided design and computer-aided manufacturing (CAD-CAM) techniques and conventional casting for a typodont model. The discrepancy values for premolar and molar abutments were measured by using the silicone replica technique after fabrication of the framework, second firing, fourth firing, and seventh firing. The replicas were separated into mesiodistal and buccolingual cross-sections, and digital images of the cross-sections were obtained with a stereomicroscope at ×80 magnification. The measurement points were examined to record the discrepancy values (µm) with in-built measuring software. The recorded data were subjected to repeated-measures 4-way ANOVA and the Bonferroni post hoc test (α=.05). RESULTS: For all measurement periods, the marginal, axial, axio-occlusal, and occlusal discrepancy values differed significantly among the manufacturing groups (P<.001). Moreover, the repeated firings had a statistically significant influence on the discrepancy values of PSAM, FHAM, and SLS groups (P<.05). The cast group was not significantly affected by repeated firings (P>.05). The PSAM group revealed the lowest discrepancy values at all measurement periods (P<.05), except after the second firing in the marginal and axial locations. CONCLUSIONS: The PSAM-fabricated restorations demonstrated superior fitting accuracy. All manufacturing groups were influenced by repeated firings, except the cast group. The marginal discrepancy values of all manufacturing groups were within the range of clinical acceptability (<120 µm).

Effect of chemical surface treatment of titanium on its bond with dental ceramics.

STATEMENT OF PROBLEM: Airborne-particle abrasion of titanium is a clinically accepted method of surface preparation. As a side effect of airborne-particle abrasion, particles of the abrasive material get embedded into the surface. How particle presence or removal from the titanium surface affects the strength of the titanium-ceramic bond is unclear. PURPOSE: The purpose of this in vitro study was to determine the effect of removing Al2O3 particles embedded into the surface by means of chemical surface treatment on the strength of the titanium-ceramic bond. MATERIAL AND METHODS: Titanium (TritanCpTi 1, Dentaurum, 99.5% Ti) disks were airborne-particle abraded with 110 µm Al2O3 at a pressure of 0.4 MPa and an angle of approximately 45 degrees. The surface was etched chemically using 1 of 8 reagents, and the veneering ceramic applied and fired. The strength of the metal-ceramic bond was determined using the shear strength test. Further, the effect of thermal fatigue on the bond strength was evaluated. The results were analyzed with 2-way ANOVA and the Tukey honest significant difference (HSD) test (α=.05). Fractographic investigations and microscopic tests were also performed to determine the quality of the titanium-ceramic bond. RESULTS: Effective etching of the titanium surface and removal of Al2O3 particles included a 30% water solution of HNO3 + 3% HF, a mixture of HNO3 + HF + glycerin, a 4% solution of HF in H2O2, and a 4% solution of HF in H2O. A statistically significant difference (of about 50%) in bond strength was found between the groups subjected to chemical etching and the control group (P<.05). Additionally, a statistically significant difference (about 25%) was found after thermocycling (P<.05). CONCLUSIONS: Removing the Al2O3 particles embedded into the titanium surface after airborne-particle abrasion lowers the strength of the titanium-ceramic bond (P<.05). Thermocycling also weakens the strength of the titanium-ceramic bond, regardless of the surface preparation (P<.05).

Dental Ceramics for Restoration and Metal Veneering.

A survey of the development of dental ceramics is presented to provide a better understanding of the rationale behind the development and clinical indications of each class of ceramic material. Knowledge of the composition, microstructure, and properties of a material is critical for selecting the right material for specific applications. The key to successful ceramic restorations rests on material selection, manufacturing technique, and restoration design, including the balancing of several factors such as residual stresses, tooth contact conditions, tooth size and shape, elastic modulus of the adhesives and tooth structure, and surface state.

Evaluation of marginal and internal gaps of metal ceramic crowns obtained from conventional impressions and casting techniques with those obtained from digital techniques.

BACKGROUND: Accuracy in fit of cast metal restoration has always remained as one of the primary factors in determining the success of the restoration. A well-fitting restoration needs to be accurate both along its margin and with regard to its internal surface. AIM: The aim of the study is to evaluate the marginal fit of metal ceramic crowns obtained by conventional inlay casting wax pattern using conventional impression with the metal ceramic crowns obtained by computer-aided design and computer-aided manufacturing (CAD/CAM) technique using direct and indirect optical scanning. MATERIALS AND METHODS: This in vitro study on preformed custom-made stainless steel models with former assembly that resembles prepared tooth surfaces of standardized dimensions comprised three groups: the first group included ten samples of metal ceramic crowns fabricated with conventional technique, the second group included CAD/CAM-milled direct metal laser sintering (DMLS) crowns using indirect scanning, and the third group included DMLS crowns fabricated by direct scanning of the stainless steel model. The vertical marginal gap and the internal gap were evaluated with the stereomicroscope (Zoomstar 4); post hoc Turkey's test was used for statistical analysis. One-way analysis of variance method was used to compare the mean values. RESULTS AND CONCLUSION: Metal ceramic crowns obtained from direct optical scanning showed the least marginal and internal gap when compared to the castings obtained from inlay casting wax and indirect optical scanning. Indirect and direct optical scanning had yielded results within clinically acceptable range.

Zirconia-based versus metal-based single crowns veneered with overpressing ceramic for restoration of posterior endodontically treated teeth: 5-year results of a randomized controlled clinical study.

OBJECTIVES: The aim of this 5-year randomized controlled trial was to compare the longevity and clinical behavior of single posterior crowns made with pressable ceramic on zirconia and on metal frameworks, and if failures occur, to delineate the contributing factors. METHODS: 72 patients, who needed the covering of at least a molar and/or premolar, were included in the study. All teeth were endodontically treated, with absence of periapical lesion or active periodontitis. Ninety single crowns were made with zirconia or metal framework and covered with pressable veneering ceramics. Two independent examiners assessed the survival of restorations at 6 months, 1-4 and 5 years after restoration placement including periapical radiographs, intraoral photographs, and USPHS modified criteria. The statistical analyses were performed with the Kaplan-Meier method. RESULTS: One core fracture occurred in Zircad/Zirpress crowns and one metal ceramic crown was lost for root fracture. Chipping fracture of the veneering ceramic was detected in 2 metal-ceramic crowns and in 3 zirconia-based crowns. The Estimate Cumulative Survival (ECS) and the Estimate Cumulative Success (ECSs) with standard deviation (SE) were respectively 97,73±2,19 and 92,64±4,14 for zirconia-based crowns whereas 97,44±2,39 and 91,11±4,27 for porcelain fused to metal crowns. CONCLUSIONS: The present randomized controlled trial shows that the survival of zirconia-based and metal-based single crowns is similar over a follow-up period of 5 years. No significant differences in esthetic, functional and biological outcomes were demonstrated between the two groups. The main failure mode was the chipping fracture of the veneering ceramic in both materials. Study number on ClinicalTrial.gov NCT02758457. CLINICAL SIGNIFICANCE: According to the results of this clinical study, zirconia-based rehabilitations with overpressing veneering technique represent a valid alternative to metal-based for posterior single crown restorations.

Incidência de fraturas em próteses fixas: estudo retrospectivo. Análise da sobrevivência de próteses metalocerâmicas após um período mínimo de quatro anos em função / Fractures incidence on fixed prostheses: a retrospective study

As próteses metalocerâmicas ainda são apontadas como o tratamento de escolha em reabilitação oral por apresentarem altas taxas de sobrevivência, mesmo que o fator estético possa ser comprometido devido às propriedades óticas relacionadas à infraestrutura metálica. Além disso, há pouca informação na literatura científica sobre os fatores que levam às fraturas das próteses fixas metalocerâmicas. Com isso, o presente estudo teve como objetivo avaliar se a quantidade de elementos que compõe uma prótese, se a quantidade de elementos por retentor, se o tipo de prótese, se o tipo de pilar, se a localização da prótese, se o bruxismo e se a utilização de placa miorrelaxante influenciam na incidência de fraturas em próteses fixas metalocerâmicas. Para este estudo, foram selecionados 16 pacientes, totalizando 74 próteses metalocerâmicas, instaladas entre 2000 e 2010, que tiveram um acompanhamento mínimo de 4 anos. Foram coletados dados, como: gênero, idade, data de instalação das próteses e sistema cerâmico utilizado. Foi realizada a avaliação clínica considerando integridade da prótese, características do elemento antagonista e coleta da história odontológica em caso de fratura, além de um questionário para identificar provável ou possível bruxismo. Foram determinadas as taxas de sucesso, insucesso e sobrevivência da mesma. Os resultados mostraram que a taxa de sucesso das próteses metalocerâmicas instaladas foi de 87,8% e a taxa de sobrevivência foi de 89,1%. Além disso, a taxa de sucesso não foi influenciada pela idade (p=0,903), tempo de instalação (p=0,830), número de próteses na boca (p=0,872), número de elementos (p=0,937) e número de pilares (p=0,064). Para as variáveis qualitativas também não houve diferença estatística significante (p>0,05) entre as proporções das taxas de sucesso e insucesso. Contudo, os resultados mostraram que pacientes que não usavam placa miorrelaxante tiveram taxa maior de sucesso que os pacientes usuários de placa (p=0,004). Assim, pode-se concluir que as próteses metalocerâmicas apresentam altas taxas de sucesso e sobrevida garantindo a longevidade desse tipo de reabilitação.(AU)

Metal-ceramic prosthesis are still the treatment choice in oral rehabilitation because they present high survival rates, even if the aesthetic can be compromised due to optical properties related to metallic infrastructure. In addition, there is little information on scientific literature about factors that lead to fractures of fixed metalceramic prosthesis. The purpose of this study was to evaluate if prosthesis elements number, number of elements per prosthetic abutment, type of prosthesis, type of prosthetic abutment, the prosthesis location, bruxism and myorelaxant plaque influences on incidence of fractures in fixed metal-ceramic prosthesis. For this study, 16 patients were selected totaling 74 metal-ceramic dentures installed between 2000 and 2010 with a follow-up of at least 4 years. Data were collected, such as: gender, age, prosthesis installation date and the ceramic system used. Besides a questionnaire to identify probable or possible bruxism, a clinical evaluation was performed to evaluate prosthesis integrity, antagonist element characteristics and dental history in case of fracture. Success, failure and survival rates were determined. The results showed that the success rate of metal-ceramic prosthesis was 87.8% and the survival rate was 89.1%. In addition, the success rate was independent of age (p=0.903), installation time (p=0.830), number of prosthesis (p=0.872), elements (p=0.937) and abutments (p=0.064). The qualitative variables also did not show significant statistical results (p> 0.05) between success and failure rates. However, the results showed that patients who did not use myorelaxant plaque had a higher success rate than plaque users (p=0.004). Thus, it can be concluded that the metal-ceramic prosthesis has high success and survival rates, ensuring longevity of this type of rehabilitation.(AU)

In Vitro Bioactivity Study of RGD-Coated Titanium Alloy Prothesis for Revision Total Hip Arthroplasty.

Total hip arthroplasty (THA) is a common procedure for the treatment of end-stage hip joint disease, and the demand for revision THA will double by 2026. Ti6Al4V (Titanium, 6% Aluminum, and 4% Vanadium) is a kind of alloy commonly used to make hip prothesis. To promote the osseointegration between the prothesis and host bone is very important for the revision THA. The peptide Arg-Gly-Asp (RGD) could increase cell attachment and has been used in the vascular tissue engineering. In this study, we combined the RGD with Ti6Al4V alloy using the covalent cross-linking method to fabricate the functional Ti6Al4V alloy (FTA). The distribution of RGD oligopeptide on the FTA was even and homogeneous. The FTA scaffolds could promote mouse osteoblasts adhesion and spreading. Furthermore, the result of RT-qPCR indicated that the FTA scaffolds were more beneficial to osteogenesis, which may be due to the improvement of osteoblast adhesion by the RGD oligopeptide coated on FTA. Overall, the FTA scaffolds developed herein pave the road for designing and building more efficient prothesis for osseointegration between the host bone and prothesis in revision THA.

In vitro evaluation of marginal, axial, and occlusal discrepancies in metal ceramic restorations produced with new technologies.

STATEMENT OF PROBLEM: Marginal and axial discrepancies of metal ceramic restorations are key to their long-term success. Little information is available for metal ceramic restorations fabricated with soft metal milling and laser sintering technologies. PURPOSE: The purpose of this in vitro study was to compare the marginal, axial, and occlusal discrepancies in single-unit metal ceramic restorations fabricated with new production techniques with those in a single-unit restoration fabricated using a conventional technique. MATERIAL AND METHODS: After the artificial tooth was prepared, impressions were made, and 40 dies were obtained. Dies were randomly divided into 4 groups (n=10). Cobalt-chromium (Co-Cr) cast (C), hard metal milled (HM), laser sintered (LS), and soft metal milled (SM) copings were fabricated. Marginal, axial, and occlusal discrepancies of these copings were measured using the silicone replica technique before and after the application of veneering ceramic. Data were analyzed with repeated measurements 2-way ANOVAs and Bonferroni post hoc tests (α=.05). RESULTS: Significant differences were found in the increase of marginal discrepancy after the application of veneering ceramic in the LS group (P=.016). However, no significant differences in marginal discrepancy were found whether veneering ceramic was applied to copings before or after in the other groups (P>.05). With regard to marginal and occlusal discrepancies, significant differences were found among the production techniques (P<.001 and P<.05, respectively). No significant differences in axial discrepancies were found among the groups (P>.05). CONCLUSION: This in vitro study showed that metal ceramic restorations produced with HM and newly introduced SM techniques exhibited better marginal adaptations than those produced with the LS or C technique.

Implante transalveolar en sustitución de una corona espiga de pronóstico dudoso / Transalveolar implant to replace a pin crown of doubtful prognosis

La sustitución de los dientes perdidos en la región estética presenta un complejo desafío debido a la dificultad en la reforma de la apariencia natural y de la anatomía papilar. Se Presenta un caso clínico donde se sustituyó un diente con corona espiga de pronóstico dudoso, por un implante inmediato Avanza. Se trata de una paciente de 24 años de edad atendida en la consulta multidisciplinaria de Implantología de la Clínica Docente de Prótesis de Marianao. Tenía una corona espiga en el incisivo central superior derecho, con cambio de coloración que le afectaba su estética. Además se le caía constantemente y estaba ligeramente inflamada por vestibular, lo cual le producía dolor. Después de una evaluación multidisciplinaria y el consentimiento de la paciente, se procede a la retirada de la corona espiga y exodoncia de la raíz del 11 mediante la técnica de colgajo. Inmediatamente se colocó el implante Avanza y se rehabilitó con una prótesis parcial acrílica removible por razones estéticas. Con este tratamiento, la paciente mantuvo el contorno de los tejidos blandos y la altura ósea de la zona intervenida, necesarios para alcanzar excelentes resultados estéticos(AU)

Replacement of missing teeth from the esthetic region poses a complex challenge to dental specialists due to the difficulties involved in reforming natural appearance and papillary anatomy. A clinical case is presented in which a tooth with a pin crown of doubtful prognosis was replaced with an immediate Avanza implant. A 24-year-old female patient presented at the implantology multidisciplinary service of Marianao Prosthetics University Clinic. The patient had a discoloring pin crown in the upper right central incisor that affected her esthetic appearance. Furthermore, the crown constantly fell out and there was slight vestibular swelling, which caused pain. After multidisciplinary evaluation and having obtained the patients consent, the pin crown was removed and root 11 extracted by flap technique. An Avanza implant was immediately placed and rehabilitated with a removable acrylic partial denture for esthetic reasons. With this treatment, the patient maintained the soft tissue contour and bone height required to achieve appropriate esthetic results(AU)

Implante transalveolar en sustitución de una corona espiga de pronóstico dudoso* / Transalveolar implant to replace a pin crown of doubtful prognosis

La sustitución de los dientes perdidos en la región estética presenta un complejo desafío debido a la dificultad en la reforma de la apariencia natural y de la anatomía papilar. Se Presenta un caso clínico donde se sustituyó un diente con corona espiga de pronóstico dudoso, por un implante inmediato Avanza. Se trata de una paciente de 24 años de edad atendida en la consulta multidisciplinaria de Implantología de la Clínica Docente de Prótesis de Marianao. Tenía una corona espiga en el incisivo central superior derecho, con cambio de coloración que le afectaba su estética. Además se le caía constantemente y estaba ligeramente inflamada por vestibular, lo cual le producía dolor. Después de una evaluación multidisciplinaria y el consentimiento de la paciente, se procede a la retirada de la corona espiga y exodoncia de la raíz del 11 mediante la técnica de colgajo. Inmediatamente se colocó el implante Avanza y se rehabilitó con una prótesis parcial acrílica removible por razones estéticas. Con este tratamiento, la paciente mantuvo el contorno de los tejidos blandos y la altura ósea de la zona intervenida, necesarios para alcanzar excelentes resultados estéticos(AU)

Replacement of missing teeth from the esthetic region poses a complex challenge to dental specialists due to the difficulties involved in reforming natural appearance and papillary anatomy. A clinical case is presented in which a tooth with a pin crown of doubtful prognosis was replaced with an immediate Avanza implant. A 24-year-old female patient presented at the implantology multidisciplinary service of Marianao Prosthetics University Clinic. The patient had a discoloring pin crown in the upper right central incisor that affected her esthetic appearance. Furthermore, the crown constantly fell out and there was slight vestibular swelling, which caused pain. After multidisciplinary evaluation and having obtained the patients consent, the pin crown was removed and root 11 extracted by flap technique. An Avanza implant was immediately placed and rehabilitated with a removable acrylic partial denture for esthetic reasons. With this treatment, the patient maintained the soft tissue contour and bone(AU)

[Oral rehabilitation with metalloceramic restorations in patients with non-differentiated systemic connective tissue dysplasia].

False formation of connective tissues have a great influence on structure and function of organs and tissues of the human body. In prosthodontics, the changes in connective tissues greatly occur during clinical stages of preparing metal ceramic dentures. The algorithm of treatment patients with connective tissue dysplasia during metal ceramic dentures was developed and introduced into practical dentistry based on studying the morphology and functionality of dentition and clinical experience.

Retentiveness of metal coping luted to teeth of uremic patients undergoing hemodialysis using five different luting cements.

OBJECTIVES: This study aimed to assess the retention of metal copings luted to uremic teeth with five different luting agents. METHODS: A total of 35 sound natural molars was collected from uremic patients and randomly assigned into five groups (n=7). The teeth were prepared for metal copings using diamond tips and water coolant. Metal copings with a loop on the occlusal surface were fabricated using base metal alloy (Rexillium III). The copings were luted using Fuji I, glass ionomer (GI); Fuji Plus, resin-modified glass ionomer (RMGI); Panavia F 2.0, resin cement; Rely X Unicem, self-adhesive cement (SA); and Adhesor, zinc phosphate cement (ZPh). All specimens were incubated at 37°C for 24 hours, conditioned in artificial saliva for 7 days, and then thermocycled for 5000 cycles (5°C-55°C). The dislodging force was measured using a universal testing machine at a crosshead speed of 2 mm/min. The mode of failure of the loaded adhesive copings was evaluated. Statistical analyses were performed using one-way analysis of variance and Tukey post hoc test. RESULTS: GI and SA cements had the highest and the lowest mean retentive strength, respectively (580.90±17.3, 406.6±12.7). There was no significant difference between ZPh, SA, and resin cements. These cements were inferior to GI and RMGI cements (p<0.05), which showed statistically similar retentive strengths. CONCLUSIONS: The results of this study support the use of glass ionomer and resin-modified glass ionomer cements for luting of metal copings to uremic teeth with retentive preparations.

Cera para huesos en la cirugía dermatológica / Bone Wax in Dermatologic Surgery

La cera para huesos es un material inerte y maleable que se utiliza como hemostático en los defectos óseos. La curación por segunda intención es una opción terapéutica en determinados casos después de la cirugía dermatológica. En las heridas quirúrgicas profundas, con exposición de distintos tejidos como hueso o cartílago, ciertos apósitos pueden adherirse al tejido de granulación. Esto dificulta y hace muy dolorosa la curación posterior. En estos casos la aplicación de un molde con cera para huesos proporciona un microambiente oclusivo hemostático ideal que favorece la cicatrización por segunda intención (AU)

Bone wax is an inert, malleable material used as a hemostatic agent in treating surgical defects. Healing by secondary intention is an appropriate approach for certain situations in dermatologic surgery. When surgical wounds are deep enough for such tissues as bone or cartilage to be exposed, dressings may adhere to granulation tissue, making removal and subsequent wound care difficult and painful. In such cases bone wax can be molded around deep tissues to create an ideal occlusive, hemostatic microenvironment that facilitates second-intention wound healing (AU)

Bond strength of selected composite resin-cements to zirconium-oxide ceramic

Objectives: The aim of this study was to evaluate bond strengths of zirconium-oxide (zirconia) ceramic and a selection of different composite resin cements. Study Design: 130 Lava TM cylinders were fabricated. The cylinders were sandblasted with 80 µm aluminium oxide or silica coated with CoJet Sand. Silane, and bonding agent and/or Clearfil Ceramic Primer were applied. One hundred thirty composite cement cylinders, comprising two dual-polymerizing (Variolink II and Panavia F) and two autopolymerizing (Rely X and Multilink) resins were bonded to the ceramic samples. A shear test was conducted, followed by an optical microscopy study to identify the location and type of failure, an electron microscopy study (SEM and TEM) and statistical analysis using the Kruskal-Wallis test or more than two independent samples and Mann-Whitney for two independent samples. Given the large number of combinations, Bonferroni correction was applied (alfa=0.001). Results: Dual-polymerizing cements provided better adhesion values (11.7 MPa) than the autopolymerizing (7.47 MPa) (p-value M-W<0.001). The worst techniques were Lava TM + sandblasting + Silane + Rely X; Lava TM + sandblasting + Silane + Multilink and Lava TM + CoJet + silane + Multilink. Adhesive failure (separation of cement and ceramic) was produced at a lesser force than cohesive failure (fracture of cement) (p-value M-W<0.001). Electron microscopy confirmed that the surface treatments modified the zirconium-oxide ceramic, creating a more rough and retentive surface, thus providing an improved micromechanical interlocking between the cement and the ceramic. Conclusions: Best results were provided by dual-polymerizing cements associated with sandblasting or silica coating and a bonding agent containing MDP (AU)

No disponible

Cerámica 55S como sustrato para la regeneración de defectos óseos, estudio in vitro / Ceramic 55S as a substrate for the regeneration of bone defects; an in vitro study

Introducción. El objetivo de nuestro trabajo es evaluar in vitro el comportamiento y la capacidad inductora de la diferenciación osteoblástica de una vitrocerámica 55S (Vc) sobre una población de células madre mesenquimales adultas (del inglés mesenchymal stem cells [MSCs]) de conejo. Material y métodos. El material se obtuvo mediante el método sol-gel. Las células se obtuvieron de aspirado de médula ósea de conejo y se sembraron sobre la Vc y sobre el plástico (control). Las MSCs se cultivaron en dos medios de cultivo, uno estándar DMEM (medio de crecimiento [Mc]) y otro inductor del fenotipo osteoblástico compuesto por DMEM complementado con dexametasona, ß-glicerofosfáto y ácido ascórbico-2P (medio osteogénico [Mo]). Se evaluó la morfología de las células que crecieron mediante microscopía electrónica de barrido. Se usó el ensayo de reducción de sales de tetrazolio (XTT) para la evaluación del crecimiento celular. Para determinar la diferenciación celular se cuantificó la producción de osteocalcina y la pérdida del antígeno de superficie CD90, característico de las MSCs. Resultados. Durante el tiempo en cultivo las MSCs se adhirieron, proliferaron y formaron matriz extracelular mineralizada sobre la Vc, mostrando finalmente un fenotipo osteoblástico, produciendo osteocalcina y disminuyendo la expresión del antigeno CD90, independientemente del medio de cultivo utilizado. Conclusión. En base a estos resultados podemos afirmar que la Vc 55S se comportó como un material capaz de soportar la adhesión y el crecimiento de las MSCs y de inducir por sí misma la diferenciación de las MSCs a células de estirpe osteoblástica, mostrando por tanto, propiedades osteoconductoras y osteoinductoras (AU)

Introduction. The purpose of this work is to evaluate the in vitro behaviour and the capacity to induce osteoblastic differentiation of a 55S vitro-ceramic (Vc) on a population of adult rabbit mesenchymal stem-cells (MSCs). Material and methods. The material was obtained using the sol-gel method. The cells were obtained from rabbit bone-marrow aspirate and seeded over the Vc, and over plastic (control). The MSCs were cultivated in two culture media; one a standard DMEM (growth medium), and the other an osteoblastic phenotype inducer, composed of DMEM complemented with dexamethasone, ß-glycerophosphate and ascorbic acid-2-phosphate (osteogenic medium). The morphology of the cells that grew was assessed using a scanning electronic microscope. The tetrazolium salt reduction test was used for evaluating the cell growth. For cell differentiation, osteocalcin production and loss of CD90 bone surface antigen, characteristic of MSCs, were quantified. Results. During the culture time the MSCs adhered, proliferated and formed a mineralised extracellular matrix over the Vc. An osteoblastic phenotype finally being shown, producing osteocalcin and decreasing the expression of the CD90 antigen, regardless of the culture medium used. Conclusion. Based on these results we can state that Vc 55S behaved like a material capable of supporting adhesion and growth of MSCs and, in turn, inducing the differentiation of the MSCs to osteoblastic cell lines, thus showing osteoconduction and osteoinduction properties (AU)

Sistemas cerámicos puros parte I: una evolución basada en la composición / Pure ceramic systems part I: an evolution based on composition

Los continuos avances en la tecnología, materiales dentales y equipamientos han contribuido significativamente con el nivel que la Odontología estética está logrando hoy. Entre estas innovaciones, el desarrollo de restauraciones de cerámica pura ha evolucionado aportando diferentes alternativas. Las cerámicas han presentado una rápida evolución desde el punto de vista tecnológico con el objetivo de mejorar las propiedades mecánicas y ópticas. En la actualidad existen varios sistemas de cerámicas libres de metal con propiedades mecánicas y ópticas excelentes, para la confección de coronas unitarias y plurales. Estos sistemas modernos se presentan con variadas composiciones y diferentes técnicas de confección, haciendo de estos más versátiles. Dentro de esta perspectiva, el mercado odontológico ofrece una gama enorme de nuevos materiales indirectos y sistemas libres de metal para la confección de prótesis, lo que proporciona nuevas opciones, más también nuevas interrogantes para decidir entre las alternativas disponibles. En este contexto esta revisión de la literatura tiene como objetivo abordar los diferentes sistemas cerámicos del punto de vista de su composición y sus diferentes técnicas de obtención

The continuing advances in technology, dental materials and equipment have contributed significantly to improve the level of esthetic dentistry today. Among these innovations, development of pure ceramic restorations has evolved to give different alternatives. Dental ceramics have presented a rapidly technological changing to improve mechanical and optical properties. Currently there are several systems of metal free ceramics with excellent mechanical and optical properties, for making crowns and plurals. These modern systems are presented with various compositions and different preparation techniques, making these more versatile. Within this perspective, the dental market offers a huge range of new indirect and metal-free materials for prostheses, providing new options, plus also new questions to decide among the available alternatives. The aim of this review is take a view of the different ceramic systems in terms of its composition and different techniques of production

Cimentação adesiva de cerâmicas à base de zircônia / Adhesive cimentation of circonia ceramics

As cerâmicas de alto conteúdo cristalino, como a zircônia, apresentam ótimas propriedades mecânicas quando comparadas às cerâmicas convencionais, sendo cada vez mais empregadas como materiais restuaradores indiretos. Entretanto, seu sucesso também depende da formação de uma união confiável com os agentes de cimentação. O aumento do conteúdo cristalino modificou as características de adesão entre cerâmica e cimento resinoso, não existindo um protocolo de cimentação bem estabelecido na literatura...

Color y características ópticas para restauraciones estéticas de dientes anteriores / Color and optical properties for esthetic restorations in anterior teeth

Las restauraciones estéticas de dientes fracturados del sector anterior con resinas compuestas consisten en un desafío estético, principalmente cuando se trata de un único incisivo central. El aumento en la demanda por parte de los pacientes de restauraciones estéticas con mínima intervención provocó un aumento en las restauraciones directas con resinas compuestas como solución a esa demanda. Sin embargo, la obtención de restauraciones biomiméticas con características ópticas, biológicas y mecánicas óptimas exige experiencia y conocimiento de materiales y de técnicas restauradores por parte de los clínicos. El objetivo de este trabajo es describir las propiedades del color y las características ópticas de los dientes anteriores para la realización de restauraciones estéticas junto con la presentación de un caso de fractura de un incisivo central superior restaurado con resina compuesta directa donde la forma, textura y color fueron fielmente reproducidos a partir de una secuencia detallada de estratificación y de técnicas de acabado/pulido

Esthetic restorations of dental fractures in the anterior segment with composite resins remain in a complex aesthetic challenge, mainly when it is about a single central incisor. Increased patient demand for aesthetic dentistry with minimal invasive procedures has resulted in the extensive use of direct composite resin restorations to overcome this challenge. However, the achievement of biomimetics restorations with optimal optical, biological and mechanical characteristics demands on clinicians experience and knowledge of materials and restorative techniques. The aim of this article is to describe color and optical properties of anterior teeth for esthetics restorations presenting a case of direct composite resin restoration of a single central incisor fractured where the shape, texture and color were faithfully reproduced following a step-by-step sequence of layering and finishing/polishing techniques

Effect of metal selection and porcelain firing on the marginal accuracy of titanium-based metal ceramic restorations.

STATEMENT OF PROBLEM: Titanium is the most biocompatible metal used for dental casting; however, there is concern about its marginal accuracy after porcelain application since this aspect has direct influence on marginal fit. PURPOSE: The purpose of this study was to determine the effect that metal selection and the porcelain firing procedure have on the marginal accuracy of metal ceramic prostheses. MATERIAL AND METHODS: Cast CP Ti, milled CP Ti, cast Ti-6Al-7Nb, and cast Ni-Cr copings (n=5) were fired with compatible porcelains (Triceram for titanium-based metals and VITA VMK 95 for Ni-Cr alloy). The Ni-Cr alloy fired with its porcelain served as the control. Photographs of metal copings placed on a master die were made. Marginal discrepancy was determined on the photographs using an image processing program at 8 predetermined locations before airborne-particle abrasion for porcelain application, after firing of the opaque layer, and after firing of the dentin layer. Repeated-measures 2-way ANOVA was used to investigate the effect of metal selection and firing stage, and paired t tests were used to determine the effect of each firing stage within each material group (alpha=.05). RESULTS: ANOVA showed that both metal selection and firing stage significantly influenced the measured marginal discrepancy (P<.001), and there was interaction between the 2 variables (P<.001). Student-Newman-Keuls multiple comparison tests showed that there were significant differences between any 2 metals compared, at each stage of measurement. Paired t tests showed that significant changes in marginal discrepancy occurred with opaque firing on milled CP Ti (P=.017) and cast Ti-6Al-7Nb alloy (P=.003). CONCLUSIONS: Titanium copings fabricated by CAD/CAM demonstrated the least marginal discrepancy among all groups, while the base metal (Ni-Cr) groups exhibited the most discrepancy of all groups tested.