Clinical application of lithium disilicate glass ceramic cantilever resin-bonded fixed partial denture in the restoration of single anterior tooth loss / 口腔疾病防治

Objective@#To investigate the clinical effect of lithium disilicate glass ceramic cantilever resin-bonded fixed partial dentures (CRBFPDs) on single anterior tooth loss to provide a reference for the selection of restoration methods for single anterior tooth loss.@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Forty-two patients with less than two anterior teeth with monomaxillary loss were included in this study. After 6 months, 1 year, 2 years, and 3 years, the aesthetic and functional effects of the restorations and the periodontal health status were evaluated, and the visual analog scale (VAS) was used to assess patient satisfaction.@*Results@#During the observation period, the connector fractured in one case within 3 months. One case had debonded within 2 years. The aesthetic restoration effect of all lithium disilicate glass ceramic CRBFPDs was categorized as Class A. The periodontal health was good, there was no clinical absorption in the soft and hard tissues of the abutment or subbridge, periodontal status according to the evaluation indices was classified as class A, and the total satisfaction rate of the patient was 100%.@*Conclusion@#For single anterior tooth loss patients, lithium disilicate glass ceramic cantilever resin-bonded fixed partial denture can achieve the restoration effect of less invasion, better adhesion, aesthetics, comfort and good biocompatibility. With high patient satisfaction, it can be considered an ideal restoration method for replacing a single anterior tooth.

Comparison of Fracture Resistance of Endodontically Treated Teeth Restored with Different Aesthetic Post and Core Systems Under All Ceramic Restoration Luted with Two Types of Cements

Context: Fracture of endodontically treated teeth is a grave sequela that a clinician should seriously ponder. Suitable selection of restorative materials is a requisite for long?term clinical success. Aims: To compare the fracture resistance of endodontically treated teeth restored with three different posts luted using two different cements under all ceramic crowns. Settings and Design: This in vitro study was conducted in the Department of Prosthodontics, Government Dental College, Kottayam, Kerala, India. Methods and Material: Thirty endodontically treated single?rooted mandibular premolars in which post spaces were prepared and divided into three different groups. Group 1 (n = 10): zirconia post group. Group 2 (n = 10): quartz fibre post group. Group 3 (n = 10): glass fibre post group. Each group is sub?divided into two based on the luting system: resin?modified glass ionomer cement (RMGIC) or dual?cure resin cement (DCRC). The fracture resistance testing was performed in a universal testing machine with a crosshead speed of 0.5 mm/min. Statistical Analysis Used: The mean fracture resistance were analysed using independent sample Student t?test and one?way ANOVA. Results: Within the zirconia post group, the mean fracture resistance was higher in DCRC sub?group compared to the RMGIC sub?group and the difference was statistically significant (p = 0.017). The difference in fracture resistance between three different post systems was not found to be statistically significant with respect to both the luting systems. Conclusions: It was observed that when zirconia post is used, the mean fracture resistance was higher in dual?cure resin group compared to the resin?modified GIC group.

Evaluation of short- and long-term bond strength of zirconia after different surface treatments / Avaliação da resistência de adesão de curto e longo prazo de zircônia após diferentes tratamentos de superfície

Objective: The aim of the study was to evaluate the short and long-term effects of different surface treatments on the bond strengths of zirconia. Material and Methods: 225 blocks of sintered zirconia samples (4 x 4 x 3 mm) were divided into five groups and subjected to different surface treatments: control group (without surface treatment), alumina group (sandblasting [25-µm-aluminum-oxide]), alumina+Ambar Universal-APS (AU) group, CoJet group (silica-coated [30-µm silica-modified aluminum particles]), and CoJet+AU group. Subsequently, zirconia samples were cemented against resin samples (total dimensions: 8x8x6mm) and assigned to three storage conditions: dry, humid (artificial saliva at 37°C for 30-days) or thermocycling [100.000-cycles] (n=15 per group). The microtensile bond strength (µTBS) was determined using a universal testing machine. The failure modes were observed and analyzed using a stereomicroscope. Normality tests, descriptive statistics, and two-way ANOVA, followed by post-hoc comparisons, were performed to evaluate the effect of surface treatments and storage conditions on µTBS (α=0.05). Results: µTBS was influenced by surface treatment in the short and long-term (P<0.0001). The highest values were found in CoJet+AU in dry (33.51 ±2.48 MPa), humid (32.87 ±2.68 MPa) and thermocycling (21.37 ±1.68 MPa) storage conditions compared with others. Interestingly, no significant differences in µTBS were found among alum +AU and CoJet alone under any of the three storage conditions. Adhesive failure increased in all groups after thermocycling, but CoJet+AU had the lowest values of adhesive failure compared with others. Conclusion: The combination of CoJet and Ambar universal as a surface treatment for zirconia specimens provides significantly higher short and long-term bond strengths of adhesive cementation (AU)

Objetivo: O objetivo do estudo foi avaliar os efeitos de curto e longo prazo de diferentes tratamentos de superfície na resistência de adesão da zircônia. Material e Métodos: 225 blocos de amostras de zircônia sinterizada (4 x 4 x 3 mm) foram divididos em cinco grupos e submetidos a diferentes tratamentos de superfície: grupo controle (sem tratamento de superfície), grupo de alumina (jateamento de 25 µm de óxido de alumínio), grupo alumina+Ambar Universal-APS (AU), grupo CoJet (partículas de alumínio modificadas por sílica de 30 µm), e grupo CoJet+AU. Posteriormente, as amostras de zircônia foram cimentadas em amostras de resina (dimensões totais: 8x8x6mm) e designadas para três condições de armazenamento: seco, úmido (saliva artificial a 37°C por 30 dias) ou ciclagem térmica (100.000 ciclos) (n=15 por grupo). A resistência de adesão de microtensão (µTBS) foi determinada usando uma máquina de teste universal. Os modos de falha foram observados e analisados usando um estereomicroscópio. Testes de normalidade, estatísticas descritivas e ANOVA de duas vias, seguidas de comparações pos-hoc, foram realizados para avaliar o efeito dos tratamentos de superfície e das condições de armazenamento na µTBS (α=0.05). Resultados: A µTBS foi influenciada pelo tratamento de superfície a curto e longo prazo (P<0.0001). Os valores mais altos foram encontrados em CoJet+AU nas condições de armazenamento a seco (33.51 ±2.48 MPa), úmido (32.87 ±2.68 MPa) e ciclagem térmica (21.37 ±1.68 MPa) em comparação com os outros. Curiosamente, não foram encontradas diferenças significativas na µTBS entre alum +AU e CoJet sozinho em nenhuma das três condições de armazenamento. A falha adesiva aumentou em todos os grupos após a ciclagem térmica, mas CoJet+AU teve os valores mais baixos de falha adesiva em comparação com os outros. Conclusão: A combinação de CoJet e Ambar Universal como tratamento de superfície para espécimes de zircônia proporciona resistências de adesão significativamente mais altas a curto e longo prazo para cimentação adesiva. (AU)

Research on friction and wear behaviors of silicon-lithium spray coating on zirconia ceramics / 北京大学学报(医学版)

OBJECTIVE@#To study microstructure, friction and wear behaviors of silicon-lithium spray coating on the surface of zirconia ceramics and to preliminarily evaluate its esthetic so as to provide support and guidance for the clinical application.@*METHODS@#Zirconia ceramic specimens were randomly divided into three groups: coating group (two subgroups), polishing group (two subgroups), and glazing group (four subgroups), with 10 samples in each subgroup. The two subgroups of coating group were the zirconia ceramics with the untreated and preliminary polishing surfaces sprayed with silicon-lithium coating, respectively. The two subgroups of polishing group were preliminary polishing and fine polishing of zirconia ceramics, respectively. The four subgroups of glazing group were preliminarily polished zirconia ceramics glazed with Biomic and Stain/Glaze products, respectively; and untreated zirconia ceramics glazed with Biomic and Stain/Glaze products, respectively. The above 8 subgroups of zirconia ceramic specimens were used as friction pairs with 80 steatite ceramics for 50 000 chewing cycles under 50 N vertical load and artificial saliva lubrication using chewing simulation. Scanning electron microscope was used to observe the microstructure of the surface and section of the coating group, and the thickness of the coating and glazing were measured. The linear roughness of the coating and polishing groups was mea-sured using a laser confocal scanning microscope. Vickers hardness was measured using a microhardness tester and the esthetic of zirconia ceramic full crown sprayed with silicon-lithium coating was preliminarily evaluated. White light interferometer was used to measure the width, the maximum depth and the volume of the wear scars of each group, and the wear depth of steatite ceramics and wear rate of zirconia ceramic specimens were calculated. Kruskal-Wallis nonparametric test and Dunn's multiple comparisons test were used to analyze the wear depth of each group (α=0.05).@*RESULTS@#The microstructures of the silica-lithium spray coatings on the untreated and preliminarily polished zirconia ceramic surfaces showed the protruding defects, and the line roughness of coating group was larger than that of the polishing group. The median thickness of the silica-lithium spray coating on the preliminarily polished zirconia ceramic was 13.0 μm (interquartile range, IQR: 11.6, 17.9), while that of the silica-lithium spray coating on the untreated zirconia ceramic was 4.4 μm (IQR: 4.1, 4.7). The Vickers hardness and wear rate of the coating group were between the polishing group and the glazing group. The wear depths of the wear scars of steatite ceramics were the glazing group, coating group, and polishing group in descending order, and there was statistically significant difference between glazing and polishing groups (P < 0.05). With the increase of polishing procedure, the wear depth of steatite ceramics decreased in each subgroups. The orders of maximum depth and volume of wear scars of zirconia ceramic were the glazing group, coating group, and polishing group in descending order, and there was statistically significant difference in the maximum depth of wear scars between glazing and polishing groups (P < 0.05).@*CONCLUSION@#The silica-lithium spray coating on the zirconia ceramic, can be used as a new method for zirconia ceramic surface treatment, because it can increase the esthetic of zirconia ceramics compared with polishing and reduce the wear of steatite ceramics compared with glazing.

Effect of novel pre-sintered zirconia surface treatment on shear bond strength between zirconia and veneering porcelain compared to conventional surface treatments: an in-vitro study / Efeito de um novo tratamento de superfície de zircônia pré-sinterizada na resistência ao cisalhamento entre zircônia e porcelana em comparação com os tratamentos de superfície convencionais: estudo in vitro

Objective: to evaluate the effect of novel zirconia surface treatment method on shear bond strength between zirconia and veneering porcelain compared to air abrasion and CoJet surface treatment methods. Material and Methods: twenty-one zirconia ceramic discs were fabricated with diameter of 7mm and 3mm thickness and divided according to surface treatment into three subgroups, control group I: Air Abrasion (n=7), group II: CoJet (n=7) and group III: Z-etch (n=7). Porcelain was built over the zirconia specimens with a customized mold and fired in a ceramic furnace. All specimens were thermocycled (20000 cycles) between 5°C ­ 55 °C with a dwell time of 30 seconds in distilled water and shear bond strength of veneering porcelain to each zirconia specimen was tested using a universal testing machine. Results: numerical data were explored for normality by checking the distribution of data and using tests of normality (Kolmogorov-Smirnov and Shapiro-Wilk tests). One-way ANOVA test was used to compare between the groups. There was a statistically significant difference between the three groups (P-value = 0.002, Effect size = 0.503). Pair-wise comparisons between groups revealed that Z-etch showed the statistically significantly highest mean shear bond strength. Conclusion: zirconia coating using z-etch is showing promising results in promoting higher bond strength than conventional surface treatment methods as air abrasion and silica coating (AU)

Objetivo: avaliar o efeito do novo método de tratamento de superfície de zircônia na resistência ao cisalhamento entre a zircônia e a porcelana de cobertura em comparação com os métodos de abrasão a ar e jateamento com CoJet. Material e Métodos: vinte e um discos de zircônia foram confeccionados com diâmetro de 7mm e espessura de 3mm e divididos de acordo com o tratamento de superfície em três subgrupos, grupo controle I: Abrasão a ar (n=7), grupo II: CoJet (n=7) e grupo III: Z-etch (n=7). A porcelana foi aplicada sobre os espécimes de zircônia com um molde personalizado e sinterizada em forno de cerâmica. Todos os espécimes foram termociclados (20.000 ciclos) entre 5°C - 55°C com um tempo de permanência de 30 segundos em água destilada e a resistência ao cisalhamento da porcelana de cobertura foi testada através de uma máquina de ensaio universal. Resultados: os dados numéricos foram avaliados quanto à normalidade, verificando a distribuição dos dados e utilizando testes de normalidade (testes de Kolmogorov-Smirnov e Shapiro-Wilk). O teste ANOVA de um fator foi utilizado para comparar os grupos. Houve uma diferença estatisticamente significativa entre os três grupos (P-valor = 0,002, tamanho do efeito = 0,503). As comparações pareadas entre os grupos revelaram que o Z-etch apresentou a resistência de união ao cisalhamento estatisticamente significativamente mais alta. Conclusão: o revestimento de zircônia utilizando Z-etch mostrou resultados promissores para o aumento da resistência de união em comparação aos métodos convencionais de tratamento de superfície, como abrasão a ar e revestimento de sílica (AU)

Mechanical behavior of different machinable ceramic crowns using vertical and horizontal preparations: an in-vitro study / Comportamento mecânico de diferentes coroas cerâmicas usináveis usando preparos verticais e horizontais: um estudo in vitro

Objective: the aim of this study was to compare the mechanical behavior of different ceramics when used in thin vertical preparations versus traditional horizontal preparation. Material and Methods: two stainless-steel dies were milled to simulate a minimally invasive vertical preparation (VP) and a traditional horizontal preparation (HP) for an all-ceramic crown of a maxillary first premolar. The stainless-steel dies were duplicated using epoxy resin. Eighty monolithic crowns were milled and divided into 2 groups according to preparation design. Each design group was subdivided into 4 sub-groups according to material (n=10): IPS e.max CAD (lithium disilicate), Bruxzir shaded zirconia (full contour zirconia), CeraSmart (resin nanoceramic) and CEREC Tessera (advanced lithium disilicate). The crowns were cemented on their relevant epoxy resin dies using self-adhesive resin cement. All specimens were subjected to 15,000 thermocycles and then loaded to fracture in a universal testing machine. Data were analyzed using two-way ANOVA and Tukey pair wise comparison test. Results: the fracture resistance mean values of the VP (1344 + 118 N) was significantly lower than the HP design (1646 + 191 N). Ceramic crowns made of full contour zirconia had higher fracture resistance mean values (2842 + 380 N) than advanced lithium disilicate (1272 + 125 N) followed by lithium disilicate crowns (983 + 52 N) and resin nanoceramic (882 + 61 N). Conclusion: both vertical and horizontal preparations, regardless the different ceramic materials, showed clinically acceptable fracture resistance values. (AU)

Objetivo: o objetivo deste estudo foi comparar o comportamento mecânico de diferentes cerâmicas quando utilizadas em preparos verticais finos ou preparos horizontais tradicionais. Material e Métodos: dois modelos de aço inoxidável foram fresados para simular um preparo vertical minimamente invasivo (PV) e um preparo horizontal tradicional (PH) para uma coroa totalmente em cerâmica de um primeiro pré-molar superior. As matrizes de aço inoxidável foram duplicadas usando resina epóxi. Oitenta coroas monolíticas foram fresadas e divididas em 2 grupos de acordo com o desenho do preparo. Cada grupo foi subdividido em 4 subgrupos de acordo com o material (n=10): IPS e.max CAD (dissilicato de lítio), zircônia Bruxzir (zircônia de contorno total), CeraSmart (resina nanocerâmica) e CEREC Tessera (dissilicato de lítio avançado). As coroas foram cimentadas em suas respectivas matrizes de resina epóxi usando cimento resinoso autoadesivo. Todos os espécimes foram submetidos a 15.000 ciclos térmicos e então carregados até a fratura em uma máquina de teste universal. Os dados foram analisados usando ANOVA com dois fatores e teste de comparação por pares de Tukey. Resultados: os valores médios de resistência à fratura do PV (1344 + 118 N) foram significativamente menores do que PH (1646 + 191 N). As coroas de cerâmica feitas de zircônia de contorno total apresentaram maiores valores médios de resistência à fratura (2842 + 380 N) do que dissilicato de lítio avançado (1272 + 125 N), seguido por coroas de dissilicato de lítio (983 + 52 N) e resina nanocerâmica (882 + 61 N). Conclusão: preparos verticais e horizontais, independentemente dos diferentes materiais cerâmicos, apresentaram valores de resistência à fratura clinicamente aceitáveis. (AU)

Implantes de zircônia: um novo material e o surgimento de novas conexões protéticas / Zirconia implants: a new material and the emergence of new prosthetic connections

Os implantes de zircônia estão cada vez maispresentes no mercado, e no catálogo das grandes marcas, devido à sua alta capacidade estética e excelente compatibilidade com os tecidos moles, além de trazer uma opção metal freepara a Implantodontia, algo bastante discutido nos tempos atuais. No entanto, uma questão bastante observada, mas ainda pouco comentada, é o surgimento das novas conexões protéticas presentes nestes implantes. Dessa forma, a proposta deste artigo é apresentar ao leitor as conexões protéticas desses implantes de zircônia, levando-o a refletir sobre as mudanças e futuro da implantodontia.

The effect of adding nanoparticles to dental porcelain on the fracture resistance and bond strength to zirconia core

Background: Porcelain combined with zirconia core substructure has low fracture toughness. Nanoparticles are incorporated into the porcelain to boost its mechanical properties. Aims: To evaluate the effect of the incorporation of silver oxide and titanium oxide nanoparticles into porcelain powder on the bond strength of porcelain veneer to zirconia core. The flexural strength of nanoparticles?modified porcelain was also evaluated. Materials and Methods: The flexural strength of feldspathic porcelain was measured (according to ISO specifications number 6872) after the incorporation of silver and titanium oxide nanoparticles. For measuring the bond strength at the porcelain?zirconia interface, 70 bars (4 × 4 × 12 mm) of zirconia were cut and fired in a furnace. The control and nanoparticles?modified porcelain powders were built up on the zirconia bars and fired to create veneers of 3 mm height, 4 mm width and 4 mm thickness. The porcelain veneers were de?attached from the zirconia core by the universal testing machine. The failure load was recorded to calculate the bond strength. Statistical Analysis: The data were analysed with one?way analysis of variance followed by Tukey’s test. Results: The addition of 0.5–1.5% silver oxide nanoparticles to feldspathic porcelain increased the flexural strength. The addition of 1.0–4.0% titanium oxide nanoparticles to feldspathic porcelain increased the flexural strength. Either 0.5–1.0% silver oxide or 3.0–4.0% titanium oxide nanoparticles in feldspathic porcelain increased the shear bond strength to zirconia core. Conclusion: The flexural strength of porcelain veneer and the bond strength at porcelain?zirconia interface can be improved by adding either 0.5% silver oxide nanoparticles or 4% titanium oxide nanoparticles to porcelain powder.

A clinical and radiographic comparative evaluation of custom-made zirconia crowns using CAD-CAM and stainless steel crowns in primary molars

Background and Aim of Study: Early childhood caries is a multifactorial disease process affecting children below 71 months of age and continues to be a global health problem. Stainless steel crowns (SSCs) are widely used and are very popular in pediatric dentistry due to its superiority and durability when compared with multisurface amalgam restorations. However, one of the major disadvantages with these crowns is the poor esthetics. Parents often request for a more esthetic alternative to the SSC. Zirconia crowns are one of the tooth-colored full crown restorations currently available for use in primary teeth. These are available as both preformed and custom-made crowns and show excellent esthetics. However, these require extensive tooth preparation with a subgingival finish lines, which would cause gingival trauma and bleeding during the preparation. The present study uses intraoral scanners for making the custom-made zirconia crowns, which will avoid the conventional impressions. Currently, there are no studies available in pediatric dentistry regarding CAD-CAM crowns. Hence, there is a need for the study. Aim: The aim of this study is to clinically evaluate the performance of preformed SSCs and custom-made zirconia crowns in primary molars. To elicit parental and patient satisfaction with respect to preformed SSCs and custom made zirconia crowns and to radiographically compare the interproximal bone height for 1 year. Methods: The patients were selected with purposive sampling. The tooth of interest was prepared according to the crown it would receive. The upper and the lower arch of the tooth receiving custom-made zirconia crown was scanned using an intraoral scanner. The crowns were cemented using Type 1 glass ionomer cement (GIC) (SSC) and resin modified GIC (custom-made zirconia crown). After the crown placement, the patient and the parent's satisfaction was scaled regarding the time taken, comfort, cost of crown, appearance of crown, etc., using a 5-point Likert scale. A baseline radiograph was taken after crown placement. The patient was recalled every 3 months till 1 year for evaluation (loss of retention, loss of proximal contact, gingival inflammation, opposing tooth wear, and marginal integrity). At the end of 1 year, radiographs were taken to check the interproximal bone. Results: After 1 year evaluation of custom-made zirconia crowns and preformed SSCs in primary molars, it was shown that both SSC and zirconia crowns showed good gingival scores but zirconia crown was better than SSC in improving the gingival health. SSCs showed better results with respect to the opposing tooth wear and marginal adaptability. Parents as well as patients preferred a tooth-colored crown as a treatment option. Conclusion: Custom-made zirconia crowns are comparable to the preformed SSCs and they show better gingival scores and excellent color match.

Marginal adaptation and mechanical strength of endocrowns with different materials and tooth prepration design: a review / 口腔疾病防治

@#The endocrown, a modified overlay or crown, is considered to have the advantages of adhesive retention and mechanical retention. Marginal adaptation and mechanical strength are common criteria for evaluating endocrowns. This review studied these aspects of endocrowns to guide further clinical application. Results from previous academic studies indicate that endocrowns made of different materials, such as glass-based ceramics, zirconia-based ceramics and resin-based ceramics, exhibit clinically acceptable marginal adaptation. Zirconia is a common dental material, but when used in endocrowns, it tends to present a risk of irreparable tooth root fractures. Compared with products manufactured with zirconia, endocrowns manufactured with resin-based ceramics and glass-based ceramics, such as lithium disilicate ceramics, do not tend to cause irreparable results, such as tooth root fracture, but their mechanical strengths are not as good as those of zirconia. At the same time, the tooth prepration design such as the types of endocrowns, the pulp chamber extension depth and angles, the endocrown thickness can influence the mechanical strength of endocrowns as well. Compared with traditional zirconia, self-glazed zirconia, a new type of material used to restore defective teeth, has the similar elasticity modulus（210 GPa）and better aesthetic advantages, and is suitable for short crown patients with insufficient occlusal space. Further study is warranted to improve the performance of endocrowns made from ceramic materials to prevent root fracture.

Effect of porous zirconia ceramics on proliferation and differentiation of osteoblasts / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effect of porous surface morphology of zirconia on the proliferation and differentiation of osteoblasts.@*METHODS@#According to different manufacturing and pore-forming methods, the zirconia specimens were divided into 4 groups, including milled sintering group (M-Ctrl), milled porous group (M-Porous), 3D printed sintering group (3D-Ctrl) and 3D printed porous group (3D-Porous). The surface micromorphology, surface roughness, contact angle and surface elements of specimens in each group were detected by scanning electron microscope (SEM), 3D laser microscope, contact angle measuring device and energy-dispersion X-ray analysis, respectively. MC3T3-E1 cells were cultured on 4 groups of zirconia discs. The cell morphology of MC3T3-E1 cells on zirconia discs was eva-luated on 1 and 7 days by SEM. The cell proliferation was detected on 1, 3 and 5 days by cell counting kit-8 (CCK-8). After osteogenic induction for 14 days, the relative mRNA expression of alkaline phosphatase (ALP), type Ⅰ collagen (Colla1), Runt-related transcription factor-2 (Runx2) and osteocalcin (OCN) in MC3T3-E1 cells were detected by real-time quantitative polymerase chain reaction.@*RESULTS@#The pore size [(419.72±6.99) μm] and pore depth [(560.38±8.55) μm] of 3D-Porous group were significantly larger than the pore size [(300.55±155.65) μm] and pore depth [(69.97±31.38) μm] of M-Porous group (P < 0.05). The surface of 3D-Porous group appeared with more regular round pores than that of M-Porous group. The contact angles of all the groups were less than 90°. The contact angles of 3D-Ctrl (73.83°±5.34°) and M-Porous group (72.7°±2.72°) were the largest, with no significant difference between them (P>0.05). Cells adhered inside the pores in M-Porous and 3D-Porous groups, and the proliferation activities of them were significantly higher than those of M-Ctrl and 3D-Ctrl groups after 3 and 5 days' culture (P < 0.05). After 14 days' incubation, ALP, Colla1, Runx2 and OCN mRNA expression in 3D-Porous groups were significantly lower than those of M-Ctrl and 3D-Ctrl groups (P < 0.05). Colla1, Runx2 and OCN mRNA expressions in M-Porous group were higher than those of 3D-Porous group (P < 0.05).@*CONCLUSION@#The porous surface morphology of zirconia can promote the proliferation and adhesion but inhibit the differentiation of MC3T3-E1 cells.

Research progress on the application of Er: YAG laser removing all-ceramic restorations / 口腔疾病防治

@#All-ceramic restorations are widely used in oral restoration because of their beauty and high strength. Glass ceramics and zirconia all-ceramic materials are the two most widely used all-ceramic materials in the clinic. However, when all-ceramic restorations need to be removed due to marginal microleakage and secondary caries, its high strength and high bonding strength greatly increase the difficulty of removal. In recent years, clinicians have tried to use Er: YAG lasers to remove all-ceramic restorations. The Er: YAG laser can be safely and efficiently applied to the removal of glass restorations, and it can also play a role in thinner zirconia restorations. Various factors, such as the material and thickness of the all-ceramic restoration, the type of cement, and the laser power, can affect the speed of removal of the Er: YAG laser. However, the current research is limited to case reports and in vitro studies, lacking systematic clinical research. The specific mechanism of Er: YAG laser removal of all-ceramic restorations and the influence of laser frequency, adhesive type, and abutment on the removal speed need to be further demonstrated by follow-up research.

Clinical assessment of two inlay -retained bridge designs (proximal box-shaped and inlay shaped) in missing posterior teeth cases. (Randomized Clinical Trial) / Avaliação clínica de dois modelos de ponte fixa inlay (forma de caixa proximal e em forma de inlay) em casos de dentes posteriores ausentes. (Ensaio clínico randomizado)

Objective: This study aimed to evaluate the clinical performance of two inlay-retained bridge designs (proximal shaped and inlay shaped) in single missing posterior teeth cases. Material and Methods: A total of 70 cases with missing single posterior teeth were included in this study and divided into two groups with a 1:1 allocation ratio (n = 35 for each group). Group 1 (the control group): this group received an inlay retained bridge with inlay design on both abutments. Group 2 (the intervention group): this group received an inlay retained bridge with a proximal box on both abutments. PMMA resin (YAMAHACHI PMMA) was used for the try-in stage and monolithic zirconia (Katana, Kuraray) was used for the final restorations. The restoration surfaces were treated using sandblasting and Z-prime S (Bisco) and the cementation was done by using self-adhesive resin cement (Bisco). Fracture, marginal adaptation, postoperative sensitivity, caries, and gingivitis were assessed using the modified United States Public Health Service for restoration clinical assessments (MUSPHS standards) over 12 months of follow-up. Results: The results show there was no significant difference between the two groups. Kaplan-Meier survival curve was constructed to calculate the mean survival estimates of the two groups and we found that the two groups were clinically successful during a one-year follow-up. Conclusion: Both designs of inlay retained fixed dental prostheses revealed successful clinical performance in terms of Fracture, marginal adaptation, postoperative sensitivity, caries, and gingivitis (AU)

Objetivo: O objetivo deste estudo foi avaliar o desempenho clínico de dois modelos de ponte fixa por inlay (formato proximal e formato inlay) em casos de dentes posteriores perdidos. Material e Métodos: Um total de 70 casos com perda de um único dente posterior foi incluído neste estudo e dividido em dois grupos com uma razão de alocação de 1: 1 (n = 35 para cada grupo). Grupo 1 (grupo controle): Este grupo recebeu uma ponte fixa por inlay com deseho de inlay em ambos os pilares. Grupo 2 (grupo intervenção): Este grupo recebeu uma ponte fixa inlay com uma caixa proximal em ambos os pilares. Resina de PMMA (YAMAHACHI PMMA) foi usada para a etapa de try-in e a zircônia monolítica (Katana, Kuraray) foi utilizada para as restaurações finais. As superfícies das restaurações foram jateadas com Z-prime S (Bisco) e a cimentação realizada com cimento resinoso autoadesivo (Bisco). Fratura, adaptação marginal, sensibilidade pós-operatória, cárie e gengivite foram avaliadas usando o Serviço de Saúde Pública dos Estados Unidos modificado para avaliações clínicas de restauração (padrões MUSPHS) ao longo de 12 meses de acompanhamento. Resultados: Os resultados mostraram que não houve diferença significativa entre os dois grupos. A curva de sobrevida de Kaplan-Meier foi construída para calcular as estimativas de sobrevida média dos dois grupos e foi concluído que os dois grupos foram clinicamente bem-sucedidos durante um acompanhamento de um ano. Conclusão: Ambos os modelos de próteses dentárias fixas de inlay revelaram desempenho clínico bem-sucedido em termos de fratura, adaptação marginal, sensibilidade pós-operatória, cárie e gengivite(AU)

Is the Er:YAG laser affect the surface characteristics and bond strength of Y-TZP?

Abstract This study evaluated the surface characteristics and bond strength of Y-TZP treated with Er:YAG laser at different focal distances. 120 Y-TZP blocks were divided into five groups (n=24), according to the surface treatment: no treatment (C-); sandblasting with silica-coated aluminum oxide particles (C+); and Er:YAG laser application at focal distances of 1mm (Er:YAG-1), 4mm (Er:YAG-4), and 7mm (Er:YAG-7). Surface characteristics were analyzed using Vickers microhardness, confocal laser microscope, scanning electron microscopy (SEM), and X-ray diffractometer (XRD). For the bond strength test, 100 Y-TZP blocks were subdivided into two subgroups (n=10), according to the resin cement used: with (MDP+) or without 10-methacryloyloxydecyl dihydrogen phosphate (MDP-). The Vickers microhardness and surface roughness were analyzed by one-way ANOVA and bond strength by two-way ANOVA and Tukey's test for both (α=0.05). Vickers microhardness differences were not observed between the groups (p>0.05); C+ showed higher surface roughness values. SEM images showed micromorphological differences between the groups. The XRD data detected tetragonal crystals for C- and, for the other groups, tetragonal and monoclinic peaks. For bond strength, no statistically difference significance were observed among the cements with or without MDP (p>0.05) but showed significant difference between the surface treatments (C+ > C- = Er:YAG1 > Er:YAG4 = Er:YAG7) (p<0.05). Suggested that the Er:YAG laser cannot replace conventional treatment with aluminum oxide particles and the presence of MDP in the resin cement had no influence on the bond strength.

Resumo Este estudo avaliou as características de superfície e resistência de união de Y-TZP tratado com laser de Er: YAG em diferentes distâncias focais. Cento e vinte blocos de Y-TZP foram divididos em cinco grupos (n=24), de acordo com a superfície de tratamento: sem tratamento (C-); asperização com partículas de óxido de alumínio revestidas por sílica (C +); e aplicação de laser Er: YAG a distâncias focais de 1 mm (Er: YAG-1), 4 mm (Er: YAG-4) e 7 mm (Er: YAG-7). As características de superfície foram analisadas por meio de microdureza Vickers, microscópio confocal a laser, microscopia eletrônica de varredura (MEV) e difratômetro de raios-X (DRX). Para o ensaio de resistência de união, cem blocos de Y-TZP foram subdivididos em 2 subgrupos (n=10) de acordo com o cimento resinoso utilizado (n=12): com 10-metacriloiloxidecil dihidrogenofosfato (MDP+) ou sem (MDP-). Microdureza Vickers e rugosidade de superfície foram analisadas por ANOVA a 1 fator e a resistência de união por ANOVA a 2 fatores e ambos seguidos de teste complementar de Tukey (α=0,05). Não foram observadas diferenças de microdureza Vickers entre os grupos; C+ apresentou maiores valores de rugosidade superficial. Imagens de MEV mostraram diferenças micromorfológicas entre os grupos. Os dados de DRX detectaram apenas cristais tetragonais para C- e, para os outros grupos, picos de zircônia nas fases tetragonal e monoclínica. Para a resistência de união, não foram observadas diferenças estatisticamente significante entre os cimentos com e sem MDP (p>0.05), mas foram observadas diferenças significativas entre os tratamentos de superfície (C+ > C- = Er:YAG1 > Er:YAG4 = Er:YAG7) (p<0.05). Sugere-se que o laser de Er: YAG não pode substituir o tratamento convencional com partículas de óxido de alumínio e a presença de MDP no cimento resinoso não influenciou na resistência de união.

Comparison of parental satisfaction with strip crowns and primary anterior zirconia crowns in 3–5 years old children over 1 year

Background: During the past decade, parental involvement for the selection of full coronal restorations for the primary anterior teeth of their children has been increased. Two most common anterior aesthetic full coronal restorations, the strip crowns and the preformed zirconia crowns, are available options. Aim: The aim of this study is to compare parental satisfaction with strip crowns and preformed primary anterior zirconia crowns over 1 year in 3–5 years old children. Materials and Methods: Forty maxillary primary incisors were restored by either strip crown or zirconia crown in 24 children. Permuted block randomization method was used for the allocation of participants. Twenty-four parents participated were recalled to fill the questionnaire over 1 year. One parent dropped out at the end of 1 year. Data were analyzed using the t-test and Chi-square test. P < 0.05 considered statistically significant. Results: Parents were satisfied with both types of restorations. Statistically significant relationship was found between overall satisfaction and durability (P = 0.004) with strip crowns and with the color (P = 0.043) in the zirconia crowns. The parents with the lower satisfaction levels with the durability of strip crowns and color of zirconia crowns rated high overall satisfaction. Conclusion: Parental overall satisfaction was higher for preformed primary anterior zirconia crowns than strip crowns. Almost equal number of parents was satisfied with all other parameters except for durability, which was more for zirconia crowns.

Mantenedor de espacio funcional elaborado con corona de NuSmile / Elaborated functional space maintainer with zirconia NuSmile crown

La caries de la infancia temprana, al igual que otras formas de caries, se caracteriza por ser multifactorial, infecciosa y de rápida evolución. Puede presentarse como lesiones cavitadas o no cavitadas, se diagnostica principalmente en menores de seis años en la superficies de los dientes anterosuperiores, debido a que son los primeros órganos dentales en erupcionar y tienen mayor contacto con el estímulo cariogénico. En casos severos pueden llegar a ocasionar la pérdida de órganos dentales, influyendo en la salud general del paciente y repercutiendo en su autoestima y desarrollo psicosocial. Para devolver las características y funciones perdidas en ausencia de algún órgano dental, se recurre a sustituirlo mediante aparatología, mayormente en forma de un mantenedor de espacio funcional. Las necesidades estéticas individuales de cada caso generan diversas alternativas para adaptarnos a la situación del paciente (AU))

Early childhood caries, like other forms of caries, is characterized by being multifactorial, infectious, and rapidly evolving. It can present as cavitated or uncavitated lesions, it is mainly diagnosed in children under six years of age on the surfaces of the anterior superior teeth, because they are the first dental organs to erupt and have greater contact with the cariogenic stimulus. In severe cases they can cause the loss of dental organs, influencing the general health of the patient and impacting on their self-esteem and psychosocial development. In order to restore the lost features and functions in the absence of any dental organ, it is resorted to by means of appliances, mostly in the form of a functional space maintainer. The individual aesthetic needs of each case generate various alternatives to adapt to the patient's situation (AU)

CAD-FEA modeling and fracture resistance of bilayer zirconia crowns manufactured by the rapid layer technology

Abstract In the RLT (Rapid Layer Technology), veneering ceramic and framework are fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) and then cemented to obtain the restoration. This study aimed to evaluate the effect of the thickness of veneering ceramic manufactured by the RLT technique on the fracture resistance (FR) of bilayer crowns with zirconia frameworks. Twenty zirconia frameworks and twenty feldspathic posterior crowns with two different veneering ceramic occlusal thicknesses (1mm=TF1; 2mm=TF2) were manufactured using CAD/CAM system. The specimens were luted to an epoxy resin abutment with resin cement and mechanically cycled (200N and 4.5×105 Pa, 37°C, 2×106 cycles, 3Hz). The FR test was performed (10kN, 0.5mm/min), and the specimens were analyzed in a stereomicroscope. For the stress analysis (finite element analysis, FEA), a 10kN load was equal to the in vitro test, and the principal stress was evaluated. The FR data were analyzed by Student's t-test and Weibull's analysis. The thickness influenced the FR of bilayer crowns. The FR was higher in the TF2 than in the TF1 group. The TF2 group presented the highest characteristic strength compared to the group TF1. The predominant type of failure was delamination. The FEA showed higher stress concentrations below the loading application point at the veneering cement interface in the 1-mm-thick model. The bilayer crowns manufactured using the approach of 2mm of veneering ceramic promoted higher FR compared to the group with 1mm veneering ceramic. Also, the FEA showed that the veneer ceramic thickness has an effect on stress distribution in zirconia-based bilayer crowns.

Resumo Na RLT (Rapid Layer Technology), a cerâmica de cobertura e infraestrutura são fabricados pelo Computer-Aided Design / Computer-Aided Manufacturing (CAD / CAM) e cimentados para obter a restauração. Este estudo teve como objetivo avaliar o efeito da espessura da cerâmica de cobertura fabricada pela técnica RLT na resistência à fratura (RF) de coroas bilaminadas com infraestrutura de zircônia. Vinte infraestruturas de zircônia e vinte coroas posteriores feldspáticas com duas espessuras oclusais da cerâmica de cobertura (1mm = TF1; 2mm = TF2) foram fabricadas usando o sistema CAD / CAM. Os espécimes foram cimentados em preparos de resina epóxi com cimento resinoso dual e ciclados mecanicamente (200N e 4,5×105 Pa, 37° C, 2×106 ciclos, 3Hz). O teste de RF foi realizado (10kN, 0,5mm / min) e, posteriormente, os espécimes foram analisados em estereomicroscópio. Para a análise de tensão (análise de elementos finitos, FEA), uma carga de 10kN foi aplicada igual ao teste in vitro, e a tensão principal foi avaliada. Os dados de RF foram analisados pelo teste t de Student e análise de Weibull. A espessura mostrou forte influência na RF das coroas bilaminadas. A RF foi maior em TF2 do que no grupo TF1. O grupo TF2 apresentou a maior resistência característica em relação ao grupo TF1. O tipo de falha predominante foi a delaminação. O FEA mostrou maiores concentrações de tensões abaixo do ponto de aplicação da carga, na interface cimento e cerâmica de cobertura no modelo de coroa de 1 mm de espessura. As coroas de bilaminadas confeccionadas com 2 mm de cerâmica de cobertura promoveram maior RF em comparação ao grupo com cerâmica de cobertura de 1 mm. Além disso, a FEA mostrou que a espessura da cerâmica de cobertura tem um efeito na distribuição de tensões em coroas bilaminadas à base de zircônia.

The effect of sterilization and disinfection on the physical-mechanical properties of preformed crowns

Introduction: Different sizes of crowns may be tried on children since there is no universal crown size because of distinctions in tooth morphology from one child to other. During the process of trial and error, the crown gets contaminated which needs to be sterilized for reuse of crown. This study was carried out to evaluate the physical–mechanical outcome after the sterilization and disinfection of pediatric preformed crowns. Materials and Methods: In total, sixty crowns consisted of 20 each, stainless steel crowns (SSCs) (3M ESPE), preveneered stainless steel (Kinder Krowns), and Zirconia crowns (Kinder Krowns) which were divided into four groups. G1 in which crowns did not undergo any sterilization, G2 consisted of fast sterilization, similarly G3 was slow sterilization, and G4 underwent chemical disinfection using Korsolex Plus for 15 min. Following sterilization, all the crown samples were observed under a stereomicroscope at ×200 magnification and assessed for color change, crazing, dimensional stability, and fracturing. Post hoc Tukey test and two-way ANOVA were performed for comparison between types of crowns and sterilization methods, with a significance level was set at P < 0.05. Results: There was no color change or fracturing following sterilization among crowns in any of the groups. Highest crazing was noted in stainless steel and the least in Zirconia crowns. Preveneered stainless steel was the most dimensionally stable and SSCs was the least. Conclusion: No color changes and fracture were noted in any type of crowns. Preveneered stainless steel was most dimensionally stable followed by Zirconia and SSCs. Maximum crazing was seen in SSCs and nil in Zirconia.

An evaluation of the effect of different veneer materials on fracture resistance of zirconia core / Avaliação dos diferentes efeitos de materiais de revestimento na resistência à fratura do núcleo de zircônia

Objectives: this in vitro study was done to evaluate the effect of packable P60 composite and Tetric N-Ceram composite veneer material on fracture strength of zirconia cores. Material and Methods:Twenty four zirconium cores (Vita, Germany) with 0.7 mm thickness were fabricated by CAD/CAM technology and then subjected to air abrasion with 50 µm of Al2O3. Cores were randomly divided into three groups according to veneering material (group A: control group sandblasted with 50 µm Al2O3 veneered by IPS E-max Ceram porcelain, group C: sandblasted with 50 µm Al2O3, etching with hydrofluoric acid and veneered with P60 composite, group E: sandblasted with 50 µm Al2O3, etching with hydrofluoric acid and veneered with Tetric N-Ceram composite). All crowns were subjected to fracture strength test in the testing machine, with load application by steel ball indenter and 0.5 mm/min. cross head speed. Results: statistical analysis was carried out utilizing one-way ANOVA, LSD. The results of fracture strength value test showed the highest mean value was registered for group (A), and the lowest mean for group (E). One-way ANOVA test represented that, there was a statistically high significant different among all groups. LSD results showed a high significant difference increase in fracture resistance for Group A at p value (*p < 0.001 High significant). Conclusions: Within the limitation of this study, sandblasting zirconia core with 50 µm Al2O3 and veneering with conventional ceramic produced restoration with acceptable fracture resistance value (AU)

Objetivo: o objetivo desse estudo in vitro foi avaliar o efeito dos compósitos P60 compactáveis e material laminado de compósitos Tetric-N Ceram na resistência à fratura de núcleos de zircônia. Material e métodos:Vinte e quatro núcleos de zircônia (Vita, Germany) com 0.7 mm de espessura fabricados por tecnologia de CAD/CAM e sinterizados em alta temperatura (1450ºC por 60 min) de acordo com as instruções do fabricante. Núcleos totalmente de zircônias foram submetidos a abração com 50 µm de Al2O3. Os núcleos de zircônia foram divididos de forma randomiza em três grupos de acordo com o material de revestimento (grupo A: grupo controle jateado com 50 µm Al2O3 folheado com porcelana IPS E-max Ceram, grupo C: jateado com 50 µm Al2O3 , coberto com concentração 9,5% de ácido fluorídrico e folheado com resina composta compatível, grupo E: jateado com 50 µm Al2O3 coberto com concentração 9,5% de ácido fluorídrico e folheado com porcelana IPS E-max Ceram. Todos os espécimes (coroas) foram submetidos a teste de resistência a fratura com máquina de teste universal, essa máquina utilizou para aplicação de carga bola de aço com 6mm de diâmetro 0,5 mm/min de velocidade da cruzeta. Resultados: análise estatística foi realizada utilizando One-way ANOVA, LSD. O resultado da resistência a fratura mostra que o maior valor médio foi registrado no grupo A e a menor média para o grupo E. O resultado do teste One-Way ANOVA representaram que houve uma diferença estatisticamente alta e significante entre todos os grupos. LSD foi executada para mostrar a fonte de significância. Os resultados do LSD mostraram um aumento da diferença significativa alta na resistência à fratura para o grupo A no valor de p (p < 0.001 signicancia alta). Conclusão: Dentro das limitações desse estudo o uso convencional de jateamento com 50 µm Al2O3 e estratificação com cerâmica convencional produziu restauração com valor aceitável de resistência a fratura (AU)

Patient Satisfaction and Pink Esthetics of PEEK Versus Zirconium Abutments in the Esthetic Zone (A Randomized Controlled Trial) / Satisfação do paciente e estética rosa dos pilares PEEK versus Zircônia na zona estética (um ensaio clínico randomizado)

Objective: This study was performed to evaluate the use of PEEK abutments versus zirconium abutments with lithium disilicate superstructure on the esthetic acceptance and peri-implant clinical parameters. Zirconium abutments were found to have high surface roughness even after polishing. This causes a remarkable collapse of the soft tissue papilla that is a primary factor in the Pink Esthetic Score(PES), resulting in failed esthetic restoration in the anterior esthetic zone. Material and Methods:Twenty patients who needed a single implant restoration in the esthetic zone were included in this study. Eighteen patients completed screening, baseline, three-month, six-month, and twelve-month follow-up visits. At the screening visit, the patients were randomly allocated into two groups: Zirconia abutments (A) Group, and PEEK abutments (B) Group, both of which were restored with IPS e.max CAD superstructure. Patients Satisfaction was assessed by visual analogue scale (VAS). Pink esthetics score (PES), modified plaque index (mPI) and modified gingval index (mGI) were also assessed. Results: All implants were successfully osseo-integrated with a 100% survival rate over one year. Patient satisfaction was significantly higher for the PEEK group than the zirconium group. The pink esthetic score showed no statistical significance between both groups. The modified plaque index was significantly lower for the PEEK group than the zirconium group. The modified gingival index showed no statistical difference between both groups. Conclusion: PEEK revealed to be a versatile material to replace zirconium for implant abutments, due to its lower plaque affinity and higher patient satisfaction (AU)

Objetivo: Este estudo foi realizado para avaliar o uso de pilares PEEK versus pilares de zircônia com estrutura de dissilicato de lítio quanto a aceitação estética e parâmetros clínicos peri-implantares. Os pilares de zircônia apresentam alta rugosidade superficial, mesmo após o polimento. Isso causa um colapso notável da papila do tecido mole, que é um fator primário no índice estético rosa (Pink Esthetic Score - PES), resultando em falha na restauração estética na zona estética anterior. Materiais e Métodos:Vinte pacientes que precisavam de um implante unitário na zona estética foram incluídos neste estudo. Dezoito pacientes completaram a triagem, a consulta inicial e as visitas de acompanhamento de três, seis e doze meses. Durante a triagem, os pacientes foram aleatoriamente divididos em dois grupos: Grupo Pilares de Zircônia (A) e Grupo de Pilares PEEK (B), ambos foram restaurados com IPS e.max CAD. A satisfação dos pacientes foi avaliada pela escala visual analógica (VAS). O PES, o índice de placa modificado (mPI) e o índice gengival modificado (mGI) também foram avaliados. Resultados: Todos os implantes foram osseointegrados com sucesso, com uma taxa de sobrevivência de 100% ao longo de um ano. A satisfação do paciente foi significativamente maior para o grupo PEEK quando comparado com o grupo de pilares de zircônia. O índice da estética rosa não apresentou significância estatística entre os dois grupos. O índice de placa modificado foi significativamente menor para o grupo PEEK quando comparado com o grupo de pilares de zircônia. Conclusão: O PEEK revelou-se um material versátil para substituir a zircônia em pilares de implante, devido a sua menor afinidade de placa e maior satisfação do paciente. (AU)