In vivo wear determination of novel CAD/CAM ceramic crowns by using 3D alignment

PURPOSE: To determine wear amount of single molar crowns, made from four different restoratives, and opposing natural teeth through computerized fabrication techniques using 3D image alignment. MATERIALS AND METHODS: A total of 24 single crowns (N = 24 patients, age range: 18 – 50) were made from lithium disilicate (IPS E-max CAD), lithium silicate and zirconia based (Vita Suprinity CAD), resin matrix ceramic material (Cerasmart, GC), and dual matrix (Vita Enamic CAD) blocks. After digital impressions (Cerec 3D Bluecam, DentsplySirona), the crowns were designed and manufactured (Cerec 3, DentsplySirona). A dual-curing resin cement was used for cementation (Variolink Esthetic DC, Ivoclar). Then, measurement and recording of crowns and the opposing enamel surfaces with the intraoral scanner were made as well as at the third and sixth month follow-ups. All measurements were superimposed with a software (David-Laserscanner, V3.10.4). Volume loss due to wear was calculated from baseline to follow-up periods with Siemens Unigraphics NX 10 software. Statistical analysis was accomplished by Repeated Measures for ANOVA (SPSS 21) at = .05 significance level. RESULTS: After 6 months, insignificant differences of the glass matrix and resin matrix materials for restoration/enamel wear were observed (P>.05). While there were no significant differences between the glass matrix groups (P>.05), significant differences between the resin matrix group materials (P<.05) were obtained. Although Cerasmart and Enamic were both resin matrix based, they exhibited different wear characteristics. CONCLUSION: Glass matrix materials showed less wear both on their own and opposing enamel surfaces than resin matrix ceramic materials.

Evaluation of undergraduate dental students in typodont preparation for all-ceramic crowns

Background: All-ceramic crown (ACC) preparations are widely used in day-to-day dentalclinical practice. Objectives: This study aimed to evaluate all-ceramic crown preparationsperformed by pre-clinical dental students at the College of Dentistry, Jazan University inSaudi Arabia and to compare the quality of the preparations between male and female groups.Materials and Methods: A total of 95 ivory teeth were prepared by fourth-year dentalstudents (44 males, 51 females). The students prepared a maxillary right central incisor forACC after mounting in the Frasaco typodont arches. Two silicone putty indexes for maxillaryanterior were obtained that extended to cover one or two teeth on either side. The facial indexwas used to provide information about the facial reduction mesio-distally. Another index wasprepared by cutting the silicone in half along the faciolingual midline of the prepared tooth,providing us with incisal, buccal, palatal, and axial reductions, in addition to biplanereduction. The data were encoded into a Statistical Package for Social Sciences program andanalyzed accordingly using Chi-square test. Results: The preparations of ACC for maxillaryanterior teeth were acceptable, ranging within 60%-85% in all criteria, which includedstructural durability, retention, and resistance. The male group was more excellent in incisalreduction (41.0%), whereas the female group was more excellent in axial taper preparations(59.1%), resulting in significant differences between genders in this preparation criteria. Allgender groups showed acceptable tooth preparations in shoulder reductions and location offinish lines, ranging within 57%-89%. Conclusion: The preparations for ACC achieved bythese dental students were considered clinically acceptable. The students clearly understoodthe principles of crown preparation. However, they still require more practice in order tomaster the art of crown preparation.

Próteses totais fixas parafusadas sobre implantes: o uso de coroas cerâmicas cimentadas individualmente / Complete fixed implant-supported prostheses: the use of individually cemented ceramic crowns – a case report

Neste relato de caso clínico, uma paciente de 63 anos de idade apresentou-se totalmente edêntula e usuária de prótese totais há mais de 40 anos, com mordida cruzada posterior unilateral e insatisfação estética. Após uma explanação sobre as opções de tratamento existentes, a paciente optou pelos implantes dentários e novas próteses totais fixas. Após a realização dos exames radiográficos e levantamento bilateral do seio maxilar para enxertia com osso do ramo mandibular, oito implantes foram colocados nas regiões posteriores, e cinco implantes colocados entre os forames mentuais, sendo as próteses reembasadas com material macio. Após a osseointegração, foram realizados os procedimentos de transferência e montagem dos dentes artifi ciais. Ambas as infraestruturas foram desenhadas para a individualização das coroas, sendo fundidas em liga de Ni-Cr, e recebendo o suporte labial em porcelana rosa. Após a prova intraoral, o aspecto metálico foi mascarado com agente opacificador, as embocaduras dos parafusos selados com fita teflon, e as coroas cerâmicas de dissilicato de lítio cimentadas com agente resinoso dual. Além da possibilidade de higienização e troca individual das coroas em momentos de falhas, o que evita um custo elevado se a infraestrutura fosse completamente em cerâmica, esta modalidade de tratamento resgata com segurança a harmonia e a naturalidade do sorriso.

In this clinical case report, a 63 years-old patient presented with complete conventional dentures (more than 40 years of use), having posterior unilateral crossbite and esthetic failure. After explaining the available treatment options, dental implants and new complete fixed prostheses were selected. Upon radiographic and bilateral sinus grafting with autogenous bone from the mandibular ramus, 8 dental implants were placed at the posterior maxillary regions and 5 dental implants between the mental foramina, being the prostheses relined with a soft material. After the osseointegration period, the transferring procedures were made for artifi cial tooth setup. Both maxillary and mandibular infrastructures were designed to receive individual crowns, cast in Ni-Cr alloy, and receive labial support with pink porcelain. After intra-oral try-in, the metallic aspect was masked with opaque paste, the screw access channels sealed with Tefl on tape, and the lithium disilicate crowns cemented with a dual resin agent. Besides the chance for homecare oral cleaning and individual crown replacement in case of failures to avoid excessive costs compared to complete ceramic infrastructures, this treatment modality provides safety and harmony for a more natural-looking smile.

Reabilitação da mandíbula edêntula com implantes e coroas metalocerâmicas isoladas implantossuportadas: relato de caso clínico com sistema CAD/CAM / Rehabilitation of the edentulous mandible using single-tooth, implant-supported metal-ceramic crowns: case report with CAD/CAM system

A forma mais comum de reabilitação de mandíbulas edêntulas com implantes osseointegrados é a prótese total fixa parafusada tipo protocolo de Brånemark, na qual os implantes são esplintados. Este relato de caso clínico apresenta uma forma alternativa de reabilitação total de mandíbulas edêntulas, com 14 implantes cone-morse e coroas totais metalocerâmicas isoladas. Foram discutidos aspectos referentes ao planejamento, com ênfase no planejamento virtual, na necessidade de disponibilidade óssea para realização deste tipo de tratamento, nas facilidades de higienização desta modalidade de reabilitação, nas considerações biomecânicas do caso, sobretudo quanto aos possíveis riscos em manter os implantes isolados, na seleção adequada dos implantes e dos componentes protéticos, nos benefícios do conceito de platform switching incorporados aos implantes cone-morse, nos cuidados necessários de manutenção, entre outros aspectos. A técnica é extremamente delicada em todas as suas etapas, sobretudo nas fases de planejamento e cirúrgica, visando a excelência do posicionamento dos implantes, para permitir a utilização de componentes protéticos pré-fabricados (munhões universais retos) sem a necessidade de usinagem. Este tipo de reabilitação mandibular mostrou-se muito eficiente, apresentando como principais vantagens a estética otimizada, a facilidade de higienização, o aspecto emocional muito favorável e uma extrema satisfação da paciente.

The most common treatment type for edentulous mandible is the full-fixed prosthesis according to the Branemark protocol with splinted dental implants. This case report presents an alternative option with cone Morse implants, straight universal abutments, and single metal-ceramic crowns. Aspects such as virtual implant planning, bone availability, biomechanical risks for single-tooth implants, prosthetic component selection, platform-switching, and maintenance are discussed, among others. The technique is very delicate in each step, particularly at surgery and three-dimensional implant positioning for pre-fabricated prosthetic components (straight universal abutments) without previous modifications. This kind of mandibular rehabilitation was very efficient and has the advantages of esthetics, easy cleaning, favorable emotional aspects and good patient satisfaction.

Comparative Analysis of the Comprehensive Effect of All-ceramic Crowns and Metal Ceramic Crowns in the Application of Full Denture Prosthesis / 昆明医科大学学报

Objective To observe the effect of all-ceramic crowns and metal ceramic crowns in the application of full denture prosthesis. Methods 86 patients who received full denture prosthesis in the Yunnan Transportation Center Hospital of Yunnan Province from January 2012 to September 2012 were chosen as the research object. According to the order of patients admission tag,patients with the odd tag were as the control group,patients with the even were as the observation group, and 43 patients in each group. Patients in the control group received metal ceramic crown repair, and patients in the observation group received all-ceramic crown repair. Patients in the two groups were followed up for 12 months to 24 months, and the black line on the gingival cervical margin, periodontal damage and porcelain crowns crack were compared between the two groups. Results The cervical margin black line ratios in the observation group and the control group were 2.33%(1/43) and 18.60% (8/43), the difference was statistically significant ( <0.05) . 11.63% (5/43) of patients in the observation group appeared cracks and fracture, compared with the control group of 2.33% (1/43), there was a statistically significant difference ( <0.05) . Conclusion Compared with etal ceramic crowns, all-ceramic crowns in full denture prosthesis have less injury in periodontal tissue and weaker anti-crack intensity, so the clinicians should choose the all-ceramic crowns based on the patients' indications.

Aesthetic all-ceramic restorations: CAD-CAM system / Restauraciones estéticas de porcelana pura: sistemas de CAD-CAM

Aesthetic dentistry is dedicated to imitate nature by maintaining the size, shape, color and symmetry. Technology has developed metal-free ceramic materials so capable of reproducing a natural appearance, that traditional materials have been replaced by them. The yttrium partially-stabilized zirconium oxide does not only have the advantage of being extremely resistant, but it is also highly translucent. It has a translucency that allows about 50 percent of the incident light to pass through, a characteristic that is vital for providing a more natural appearance to restorations. The duration of scanning and milling procedures will depend on the size of the object, the number of objects processed and the steps selected (CAM or CAD/CAM). The framework of the densely sintered zirconium oxide with its precise fit is veneered with the veneering ceramic developed especially for this purpose. Almost in all cases, there are several treatment alternatives for the same diagnosis. The success of these restorations will be predicted as long as it is founded on sustaining biological principles. The aim of this paper is to concisely present the sequences for a clinical treatment in a schematic and illustrative manner.

La estética en odontología está orientada a imitar la naturaleza, a tratar de conservar las proporciones, las formas, el color, la simetría. La tecnología ha desarrollado materiales cerámicos libres de metal que han reemplazado a los materiales tradicionales, capaces de imitar mejor a la naturaleza. El óxido de circonio parcialmente estabilizado con itrio, no solo es extremadamente resistente, sino que posee la ventaja de ser altamente translucido. Su translucidez de aproximadamente el 50 por ciento de la luz incidente, permite la elaboración de restauraciones con apariencia natural. La duración del proceso de escaneado y fresado dependerá del tamaño del objeto, del número de objetos procesados y de los pasos seleccionados (CAM o CAD/CAM). La estructura de óxido de circonio densamente sinterizado con su preciso ajuste, se cubre con la cerámica de recubrimiento que ha sido especialmente desarrollada para este propósito. En casi todos los casos que se nos plantean hay un solo diagnóstico, pero distintas alternativas de plantear el tratamiento. El éxito de estas restauraciones será predecible siempre que sefundamente en el conocimiento de los principios biológicos que la sustentan. El objetivo de este artículo es exponer de manera concisa las bases teóricas a modo esquemático y las imágenes de la secuencia del tratamiento clínico.

A 3-year follow-up study of all-ceramic single and multiple crowns performed in a private practice: a prospective case series

OBJECTIVES: Zirconia-based prostheses are commonly used for aesthetic crown and fixed restorations, although follow-up data are limited, especially for implant-supported crowns. The aim of this study was to evaluate the threeyear clinical results of the installation of 463 zirconia core crowns by a general dental private practice. METHODS: This study followed 142 patients (69 men and 73 women; aged 28-82 years) who had received 248 single crowns (202 tooth-supported, 36 implant-supported) and 225 multiple units of up to six elements (81 toothsupported, 144 implant-supported). Clinical events, including fracture and loss of retention, secondary caries, and marginal integrity, were recorded. The overall failure rate was computed for the fractured and lost prostheses. Aesthetic, functional, and biological properties were rated, and patient satisfaction was investigated. RESULTS: During the three-year follow-up period, four patients were lost from the study (18 crowns, 4 percent of the total crowns). Three of the zirconia prostheses suffered fractures in more than three units (11 crowns; one- vs. three-year follow-up, p,0.05, Wilcoxon signed-rank test), and the cumulative prosthesis survival rate was 98.2 percent. Twelve units lost retention and were re-cemented, and no secondary caries of the abutment teeth were reported. The aesthetic, functional, and biological properties were generally well-rated, and there were no differences between tooth- and implant-supported crowns. The lowest scores were given regarding the anatomical form of the crowns, as some minor chipping was reported. Relatively low scores were also given for the periodontal response and the adjacent mucosa. Overall, patient satisfaction was high. CONCLUSIONS: At the three-year follow-up, the zirconia-core crowns appeared to be an effective clinical solution as they had favorable aesthetic and functional properties. Only the marginal fit of the prostheses should be improved upon.

Clinical evaluation of IPS e.max Press all-ceramic crowns and three-unit fixed partial dentures / 中华医学美学美容杂志

Objective To evaluate the clinical performance of IPS e.max Press all-ceramic crowns and three-unit fixed partial dentures(FPDs)and to investigate the periodontal response to the presence of the restorations.Methods According to the inclusion criteria,19 patients with dental defects or singletooth loss were recruited,including 25 crowns and 6 all-ceramic FPDs.The modified United States Public Health Service criteria were used for follow-up evaluation.Plaque index(PI)and sulcus bleeding index (SBI)were recorded for the ceramic restorations and the control teeth.Results No crown and FPD fractures were observed during the evaluation period.There was no statistically significant difference regarding PLI and SBI scores between restorative teeth and the control teeth.And the difference between different recalled times of PLI and SBI of the restorations was no statistically significant.Conclusion IPS e.max Press crowns and three-unit fixed partial dentures exhibit a satisfactory clinical performance.

Rehabilitación diente único con implante en zonas estética anterior: reporte de un caso / Restauration with a single implant in the anterior esthetic zone: a case report

El conocimiento acerca de la rehabilitación de dientes con implantes ha ido aumentando de manera potencial; los resultados favorables de la oseointegración superan el 90%, pero los conceptos para designar una restauración como exitosa cada vez se tornan mas estrictos. La estética gingival peri-implantar es ahora quien rige los parámetros de éxito o fracaso y la diferencia estructural del periodonto al rededor de un diente y de un implante es quien determina factores como la posición tridimensional, el pronóstico y el resultado estético final. Este caso reporta la rehabilitación de un incisivo central superior (considerado actualmente como el mayor reto estético) de una paciente de 22 años de edad que asiste a la clínica CES de Sabaneta (Antioquia). La corona del diente fue restaurada en varias ocasiones desde la edad de 12 años, después de sufrir un accidente de tránsito. La paciente presenta un resto radicular fracturado con caries activa en su porción cervical. La revisión de literatura incluye todos los parámetros dentales, óseos y gingivales que se tuvieron en cuenta para la colocación del implante, y su posterior rehabilitación con el sistema Procera. El tratamiento realizado fue la extracción atraumática del resto radicular, la colocación inmediata del implante, y la restauración final con una corona libre de metal utilizando el sistema Procera.

The knowledge about the rehabilitation of teeth with implants has grown up in a potential way; the favorable outcomes of Osseo integration exceed 90%, but the concepts to designate a restoration as successful have become stricter. Peri-implant gingival esthetics parameters currently determine failure or success, and the structural differences of the periodontum surrounding the tooth and implant are determining factors of three-dimensional position ofthe restoration, prognosis and final esthetic result. This case reports the rehabilitation of a central incisor of a 22 year old patient who consulted CES University Dental Clinic. Past Dental History revealed she had been treated and had the restoration and been repeated on several occasions since the age of 12 after suffering dento-alveolar trauma in an automobile accident. Oral examination showed that the patient presented a fractured root with decay on its cervical third. Treatment included a traumatic extraction of the root, immediate placementof an implant and a final restoration with a Procera all ceramic crown.

FEA estimates of margin design in all ceramic crowns / 대한치과보철학회지

STATEMENT OF PROBLEM: Over the past decade, increased demand for esthetically pleasing restorations has led to the development of all-ceramic systems. Recent reports suggest that the all-ceramic crowns have excellent physical properties, wear resistance, and color stability. In addition, numerous ceramics have excellent biocompatibility, a natural appearance, and improved physical bonding with resin composite luting agents. However, the brittle nature of ceramics has been a major factor in their restriction for universal usage. Functional occlusal loading can generate stress in the luting agent, and the stress distribution may be affected by the marginal geometry at the finish line. Tooth preparation for fixed prosthodontics requires a decision regarding the marginal configuration. The design dictates the shape and bulk of the all ceramic crowns and influences the fit at the margin. PURPOSE: The purpose of this study was to evaluate the stress distribution within marginal configurations of all- ceramic crowns (90-degree shoulder, 110-degree shoulder, 135-degree shoulder). MATERIAL AND METHODS: The force is applied from a direction of 45 degrees to the vertical tooth axis. Three-dimensional finite element analysis was selected to determine stress levels and distributions. RESULTS AND CONCLUSION: The result of stress level for the shoulder marginal configuration was more effective on stress distribution at 135-degree shoulder margin. But the stresses concentrated around at 135-degree shoulder margin. The stress decreased apically at the surface between cements and alumina core, and increased apically at the surface between alumina core and veneering porcelain.

Numerical Analysis of the Influence of Cement Thickness on Stress Distribution in All-ceramic Crowns / 航天医学与医学工程

Objective To provide theoretical basis for clinical treatment of all-ceramic crown prosthodontics,the influence of cement thickness on the stress distribution in all-ceramic crowns under load was studied numerically.Methods The finite element analysis(FEA) model of a standard mandibular first molar was established using spiral CT and CAD software,and then it was applied to analyze the stress distribution of all-ceramic crowns under vertical loading using FEA software.Results Stress concentration was found in mesial and distal cement;the stress distribution at the cement upper and lower interface was found to be similar,and the stress magnitude discrepancy between the two interfaces was small;the stress of the model with 0.15 mm cement in the cervix was lower about 30% than the one of the 0.05 mm model.Conclusions The cement thickness plays an important role in the stress distribution of all-ceramic restoration system.The model with 0.15 mm cement shows a better resistance to destruction among the three models investigated.

Effects of finish line curvature on fitness of metal ceramic crowns / 实用口腔医学杂志

Objective:To investigate the effects of abutment finish line curvature on fitness of metal ceramic crowns.Methods:Three types of finish line curvatures' abutments were prepared (1 mm-curvature, 3 mm-curvature and 5 mm-curvature). For each type of abutment, ten metal ceramic crowns were fabricated (five for facial-veneered type, five for full-veneered type). Then the fitness of the crowns were evaluated. Results:In as-cast group, both for facial-veneered type and full-veneered type, the greater the finish line curvature was, the larger gaps the mesial and distal margins of copings exhibited. Compared with labial and lingual margins, the mesial and distal margins of copings for 5 mm-curvature crowns in full-veneered type showed significantly larger gaps (respectively 35?8 micrometers and 36?8 micrometers) (P