RESUMO
PURPOSE: To evaluate the reliability and failure modes of ultrathin (0.5 mm) lithium disilicate, translucent and ultra-translucent zirconia crowns for posterior teeth restorations. MATERIALS AND METHODS: Fifty-four mandibular first molar crowns of three ceramic materials: (1) Lithium disilicate (e.max CAD, Ivoclar Vivadent), (2) 3Y-TZP (Zirconn Translucent, Vipi), and (3) 5Y-PSZ (Cercon XT, Dentsply Sirona), with 0.5 mm of thickness were milled and cemented onto composite resin abutments. Eighteen samples of each group were tested under mouth-motion step-stress accelerated life testing in a humid environment using mild, moderate, and aggressive profiles. Data was subjected to Weibull statistics. Use level curves were plotted and reliability was calculated for a given mission of 100,000 cycles at 100, 200, and 300 N. Fractographic analyses of representative samples were performed in scanning electron microscope. RESULTS: Beta (ß) values suggest that failures were dictated by material's strength for lithium disilicate and by fatigue damage accumulation for both zirconias. No significant differences were detected in Weibull modulus and characteristic strength among groups. At a given mission of 100,000 cycles at 100 N, lithium disilicate presented higher reliability (98% CB: 95-99) regarding 3Y-TZP and 5Y-PSZ groups (84% CB: 65%-93% and 79% CB: 37&-94%, respectively). At 200 N, lithium disilicate reliability (82% CB: 66%-91%) was higher than 5Y-PSZ (20% CB: 4%-44%) and not significantly different from 3Y-TZP (54% CB: 32%-72%). Furthermore, at 300 N no significant differences in reliability were detected among groups, with a notable reduction in the reliability of all materials. Fractographic analyses showed that crack initiated at the interface between the composite core and the ceramic crowns due to tensile stress generated at the intaglio surface. CONCLUSIONS: Ultrathin lithium disilicate crowns demonstrated higher reliability relative to zirconia crowns at functional loads. Lithium disilicate and zirconia crown's reliability decreased significantly for missions at higher loads and similar failure modes were observed regardless of crown material. The indication of 0.5 mm thickness crowns in high-load bearing regions must be carefully evaluated. CLINICAL SIGNIFICANCE: Ultraconservative lithium disilicate and zirconia crowns of 0.5 mm thickness may be indicated in anterior restorations and pre-molars. Their clinical indication in high-load requirement regions must be carefully evaluated.
Assuntos
Coroas , Porcelana Dentária , Reprodutibilidade dos Testes , Teste de Materiais , Cerâmica , Zircônio , Análise do Estresse Dentário , Falha de Restauração Dentária , Desenho Assistido por ComputadorRESUMO
STATEMENT OF PROBLEM: Although the 2D analysis of prosthesis cementation space has been popular, its correlation with volumetric comparison (3D data) of cement space is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the cement space in computer-aided design and computer-aided manufacturing (CAD-CAM) crowns of different materials and correlate 2D measurements of cement space with their corresponding 3D values (volume of cement space) by using microcomputed tomography (µCT) analysis of regions of interest. MATERIAL AND METHODS: Ten molar crowns were milled in lithium disilicate (LD), resin nanoceramic (RN), and zirconia (Z) ceramics. Silicone replicas were produced and used as the analog cement layer and scanned with a desktop X-ray microfocus CT scanner. Twenty-eight slices were evaluated in 3 regions: marginal, axial, and occlusal (n=84 measurement points/specimen). After 3D reconstruction of the cement space, the volume was calculated. Data were statistically evaluated through 2-way ANOVA and Bonferroni test (α=.05). The Pearson correlation test was used to investigate the correlation between the 2D and 3D data. RESULTS: The volumes of the occlusal (LD 10 ±1 mm3; RN 9 ±1 mm3) and axial regions (LD 9 ±2 mm3; RN 8 ±1 mm3) were significantly higher than the volume of the marginal region for LD and RN specimens (LD 6 ±2 mm3; RN 4 ±1 mm3) (both P<.001). For the Z group, the axial region had the highest volume (19 ±2 mm3), followed by the volumes of the occlusal (15 ±1 mm3) and marginal regions (12 ±1 mm3). The Pearson correlation test determined a moderate positive correlation of the marginal area (r=0.606, P<.001) and of the axial region (r=0.588, P<.001). However, a moderate negative correlation was found between volume and thickness of the occlusal area (r=-0.437, P=.016). CONCLUSIONS: Z showed more volume of cement space, as well as thicker cement space than LD and RN. The µCT analysis is an efficient method of analyzing cement thickness and volume in ceramic crowns at the selected regions of interest. A moderate positive correlation was found between the 2D and 3D analyses for the axial and marginal regions of ceramic crowns.
Assuntos
Adaptação Marginal Dentária , Planejamento de Prótese Dentária , Microtomografia por Raio-X , Coroas , Desenho Assistido por Computador , Porcelana Dentária , Materiais Dentários , Cerâmica , Cimentos Dentários/uso terapêutico , Cimentos de Ionômeros de VidroRESUMO
STATEMENT OF PROBLEM: Identical computer-aided design (CAD) parameters may be used to mill a variety of ceramic materials for computer-aided design and computer-aided manufacture (CAD-CAM) crowns. Whether milled crown spacing matches the designed parameters when more than a single evaluation method is applied is unknown. PURPOSE: The purpose of this in vitro study was to correlate the stereomicroscope and the microcomputer tomography (µCT) 2-dimensional analysis of the cementation space with the replica technique in assessing 3 different ceramic materials. MATERIAL AND METHODS: The specimens were milled in lithium disilicate, resin nanoceramic, and zirconia (n=30). The cement space was measured at the marginal, axial, and occlusal regions. One hundred twenty measurements of each material were used to correlate the methodologies. Data were statistically evaluated with 2-way repeated measures ANOVA and the Tukey test (α=.05). The Pearson correlation coefficient was used for each region for both methodologies (µCT and optical microscopy) separately. RESULTS: For the µCT analysis, no differences were observed (P>.05) among the materials, but the axial region showed a positive correlation with the marginal (r=0.957) and occlusal regions (r=0.349); the same was observed between the occlusal and marginal regions (r=0.338). However, for stereomicroscope evaluation, resin nanoceramic and zirconia present similar cementation space (P=960), both being different from lithium disilicate (P<.05). The marginal region presented a positive correlation with axial (r=0.149) and occlusal regions (r=0.344), but the axial region showed negative correlation with the occlusal surface (r=-0.205). CONCLUSIONS: The measurements of the scanned replicas were accurate when thinner sections were under measurement. Although the same space parameters were set in the CAD software program, definitive internal dimensions varied among the milled crowns.
Assuntos
Cimentação , Adaptação Marginal Dentária , Cerâmica , Desenho Assistido por Computador , Coroas , Porcelana Dentária , Planejamento de Prótese DentáriaRESUMO
PURPOSE: To evaluate the pullout resistance of CAD/CAM implant-supported crowns cemented with provisional and definitive cements on Ti-base implant abutments. MATERIALS AND METHODS: Sixty crowns were milled for use in Ti-base implant abutments and divided (n = 15/group) according to material, as follows: (a) [Pr] Temporary acrylic resin; (b) [Co-Cr] Cobalt-Chromium alloy; (c) [Zr] polycrystalline zirconia; and (d) [Ti] titanium. The cementation was performed with RelyX Temp NE (RxT) cement or RelyX U200 self-etching resin cement, under a 50 N (5 kg) load for 10 minutes. Twenty-four hours after cementation, the crowns were subjected to the pullout test in a universal test machine, at a 1.0 mm/min crosshead speed. The tests were performed first without cement to evaluate frictional resistance (Baseline), then with provisional cement (RelyX Temp NE without cement again (Baseline After RxT), and finally with resin cement (U200). The results were analyzed by ANOVA and Tukey test (p < 0.05). RESULTS: Data evaluation as a function of cement type demonstrated the superiority of resin-based cements relative to provisional and baseline groups (p < 0.01). While Co-Cr crowns presented the highest pullout strength values, Pr showed the lowest values (data collapsed over cement) (p < 0.001). Retentiveness data as a function of both factors demonstrated similar pullout resistance between groups without cement (p < 0.001), except Zr baseline. Also, Co-Cr presented higher pullout strength compared to other materials. CONCLUSIONS: Self-adhesive resin cement exhibited superior retention compared to temporary cement, regardless of crown material. Co-Cr and titanium presented higher levels of retention to Ti-base abutment after being cemented.
Assuntos
Cimentação/métodos , Desenho Assistido por Computador , Coroas , Dente Suporte , Materiais Dentários/química , Ligas de Cromo/química , Teste de Materiais , Cimentos de Resina/química , Titânio/química , Zircônio/químicaRESUMO
PURPOSE: To evaluate Ti-Base abutment height and cement type on the retentiveness of zirconia-based restorations. MATERIAL AND METHODS: Four millimeter (tall) and 2.5-mm-height (short) abutments along with temporary (provisional), glass ionomer (Meron), self-adhesive (U200), and conventional resin cement (Ultimate) were evaluated using pull-out testing (n = 10 crowns/group). RESULTS: Tall and short abutments demonstrated similar retention for all within cement comparisons, except U200 (P = 0.032). Resin cements exhibited superior retentiveness than others (P < 0.01). Although no significant difference was evidenced between resin cements for short abutments, Ultimate evidenced higher retention than U200 for tall abutments (P = 0.043). CONCLUSIONS: Although Ti-Base abutment height has not influenced zirconia superstructures' retentiveness, resin-based cements significantly evidenced higher retention than glass ionomer and temporary cements.
Assuntos
Desenho Assistido por Computador , Coroas , Dente Suporte , Cimentos Dentários/uso terapêutico , Projeto do Implante Dentário-Pivô , Planejamento de Prótese Dentária , Zircônio , Planejamento de Prótese Dentária/métodos , Restauração Dentária Permanente/métodos , Análise do Estresse Dentário , Cimentos de Ionômeros de Vidro/uso terapêutico , Humanos , Cimentos de Resina/uso terapêuticoRESUMO
To develop a peri-implantitis model in a Gottingen minipig and evaluate the effect of local application of salicylic acid poly(anhydride-ester) (SAPAE) on peri-implantitis progression in healthy, metabolic syndrome (MS), and type-2 diabetes mellitus (T2DM) subjects. Eighteen animals were allocated to three groups: (i) control, (ii) MS (diet for obesity induction), and (iii) T2DM (diet plus streptozotocin for T2DM induction). Maxillary and mandible premolars and first molar were extracted. After 3 months of healing, four implants per side were placed in both jaws of each animal. After 2 months, peri-implantitis was induced by plaque formation using silk ligatures. SAPAE polymer was mixed with mineral oil (3.75 mg/µL) and topically applied biweekly for up to 60 days to halt peri-implantitis progression. Periodontal probing was used to assess pocket depth over time, followed by histomorphologic analysis of harvested samples. The adopted protocol resulted in the onset of peri-implantitis, with healthy minipigs taking twice as long to reach the same level of probing depth relative to MS and T2DM subjects (â¼3.0 mm), irrespective of jaw. In a qualitative analysis, SAPAE therapy revealed decreased levels of inflammation in the normoglycemic, MS, and T2DM groups. SAPAE application around implants significantly reduced the progression of peri-implantitis after â¼15 days of therapy, with â¼30% lower probing depth for all systemic conditions and similar rates of probing depth increase per week between the control and SAPAE groups. MS and T2DM conditions presented a faster progression of the peri-implant pocket depth. SAPAE treatment reduced peri-implantitis progression in healthy, MS, and T2DM groups.
Assuntos
Peri-Implantite , Ácido Salicílico , Porco Miniatura , Animais , Suínos , Peri-Implantite/tratamento farmacológico , Peri-Implantite/patologia , Ácido Salicílico/administração & dosagem , Ácido Salicílico/farmacologia , Ácido Salicílico/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Modelos Animais de Doenças , Progressão da Doença , Hiperglicemia/tratamento farmacológico , Masculino , Diabetes Mellitus Experimental/tratamento farmacológico , Síndrome Metabólica/tratamento farmacológico , Síndrome Metabólica/metabolismo , Implantes DentáriosRESUMO
The aim of this study was to evaluate the bone healing of tight-fit implants placed in the maxilla and mandible of subjects compromised with metabolic syndrome (MS) and type-2 Diabetes Mellitus (T2DM). Eighteen Göttingen minipigs were randomly distributed into three groups: (i) control (normal diet), (ii) MS (cafeteria diet for obesity induction), (iii) T2DM (cafeteria diet for obesity induction + Streptozotocin for T2DM induction). Maxillary and mandibular premolars and molar were extracted. After 8 weeks of healing, implants with progressive small buttress threads were placed, and allowed to integrate for 6 weeks after which the implant/bone blocks were retrieved for histological processing. Qualitative and quantitative histomorphometric analyses (percentage of bone-to-implant contact, %BIC, and bone area fraction occupancy within implant threads, %BAFO) were performed. The bone healing process around the implant occurred predominantly through interfacial remodeling with subsequent bone apposition. Data as a function of systemic condition yielded significantly higher %BIC and %BAFO values for healthy and MS relative to T2DM. Data as a function of maxilla and mandible did not yield significant differences for either %BIC and %BAFO. When considering both factors, healthy and MS subjects had %BIC and %BAFO trend towards higher values in the mandible relative to maxilla, whereas T2DM yielded higher %BIC and %BAFO in the maxilla relative to mandible. All systemic conditions presented comparable levels of %BIC and %BAFO in the maxilla; healthy and MS presented significantly higher %BIC and %BAFO relative to T2DM in the mandible. T2DM presented lower amounts of bone formation around implants relative to MS and healthy. Implants placed in the maxilla and in the mandible showed comparable amounts of bone in proximity to implants.
Assuntos
Implantes Dentários , Diabetes Mellitus Tipo 2 , Animais , Implantação Dentária Endóssea , Diabetes Mellitus Tipo 2/complicações , Mandíbula/cirurgia , Obesidade , Osseointegração , Próteses e Implantes , Propriedades de Superfície , Suínos , Porco MiniaturaRESUMO
Properties and composition of leukocyte- and platelet-rich fibrin (L-PRF) clots may be largely affected by centrifugation protocols (function of relative centrifugal force [RCF]), which may impact biological potential repair in bone regeneration. The present in vivo study sought to assess the effect of the RCF on the composition of L-PRF clots, as well as to compare the repair potential of L-PRF clots obtained with different RCF protocols in submandibular boney defects using PLGA scaffolds for bone regeneration. Complete blood count and volumetric evaluations were performed on L-PRF clots obtained through centrifugation for 12 min at 200, 400, and 600 RCF-clot centrifugation speeds. These evaluations were completed from blood collected immediately prior to any surgical procedures. The in vivo portion comprised of three submandibular unilateral, full thickness, osteotomies (~0.40cm3 ) which were created in the submandibular region of six sheep, using rotary instrumentation under continuous irrigation. Subsequently, poly(lactic-co-glycolic acid) (PLGA) scaffolds were enveloped in a L-PRF membrane from one of the three spinning speeds (n = 6/RCF) and inserted into the defect (sites were interpolated to avoid site bias). Six-weeks after surgery, the mandibles were harvested en bloc and prepared for volumetric and histomorphometric evaluations. Membranes harvested from 600 RCF produced significantly larger L-PRF clots (6.97g ± 0.95) in comparison to the lower 200 RCF (5.7g ± 0.95), with no significant differences between 600 and 400, and from 400 and 200 RCF. The three tested RCFs did not alter the platelet count of the L-PRF clot. For the in vivo component, quantitative bone regeneration analyses demonstrated significantly higher values obtained with L-PRF membranes extracted post 600 RCF (27.01 ± 8%) versus 200 RCF (17.54 ± 8%), with no significant differences regarding 400 RCF (~23 ± 8%). At the qualitative histological analyses, L-PRF membranes obtained at 600 and 400 RCFs yielded improved healing throughout the defect, where the L-PRF sourced from the lowest speed, 200 RCF, presented healing primarily at the margins along with the presence of connective tissue at the central aspect of the surgical defect. Higher 600 RCF yielded larger L-PRF clots/membranes, resulting in enhanced bone repair potential in association with PLGA scaffolds for the treatment of critical size bone defects.
Assuntos
Fibrina Rica em Plaquetas , Animais , Regeneração Óssea , Centrifugação/métodos , Leucócitos , Mandíbula , OvinosRESUMO
OBJECTIVES: To evaluate the three-dimensional fit of abutments fabricated by the industry to those either milled or cast by a commercial laboratory and to correlate the implant-abutment connection fit with stress at fatigue failure of prostheses. Probability of survival (reliability) and fractography to characterize failure modes were also performed for cemented and screw-retained prostheses. METHODS: One-hundred and twenty-six maxillary central incisor crowns were milled to restore implants and divided in 3 cemented and 3 screwed-retained groups (nâ¯=â¯21/each), as follows: [Digital-Sc]: milled one-piece monolithic abutment/crown; [TiB-Sc]: milled crowns cemented onto Ti-base abutments; [UCLA]: screw-retained crown using UCLA abutments; [Digital-Ce]: milled two-piece assembly comprised by screwed monolithic abutment and a cemented crown; [TiB-Ce]: milled coping cemented onto Ti-base abutments to receive a cemented crown; [UCLA-Ce]: UCLA abutments that received an overcast coping and a cemented crown. Implant-abutment volume misfit was assessed by micro-computed tomography using the silicone replica technique. Implant/crown systems were subjected to step-stress accelerated life testing (SSALT) in water. The use-level probability Weibull curves and reliability for a mission of 50,000 cycles at calculated stress at failure of 2,300, 3300 and 4300â¯MPa were plotted. Fractographic analysis was performed with scanning electron microscopy. Internal misfit was analyzed through one-way ANOVA following post-hoc comparisons by Tukey test (pâ¯<â¯0.05). Correlation between misfit volume and the stress at fatigue failure was assessed by Pearson test. RESULTS: Similar misfit volumes were observed for TiB-Sc (0.458â¯mm3), TiB-Ce (0.461â¯mm3), UCLA (0.471â¯mm3) and UCLA-Ce (0.480â¯mm3), which were significantly lower than Digital-Sc (0.676â¯mm3) and Digital-Ce (0.633â¯mm3). The mean ß values were: 1.68, 1.39, 1.48, 2.41, 2.27 and 0.71 for Digital-Sc, TiB-Sc, UCLA, Digital-Ce, TiB-Ce and UCLA-Ce, respectively, indicating that fatigue was an accelerating factor for failure of all groups. Higher stress at failure decreased the reliability of all groups, more significantly for screw compared to cement-retained groups, especially for Digital-Sc that demonstrated the lowest reliability. The failure mode was restricted to abutment screw fracture. A negative correlation was observed between misfit values and stress at failure (râ¯=â¯-0.302, pâ¯=â¯0.01). CONCLUSIONS: Abutments milled by a commercial lab presented higher misfit compared to those provided by the industry and a moderate correlation was observed between higher misfit and lower stress at failure during fatigue. Probability of survival decreased at higher stress, especially for screw compared to cement-retained groups, and failures were confined to abutment screws.
Assuntos
Coroas , Incisivo , Falha de Restauração Dentária , Análise do Estresse Dentário , Próteses e Implantes , Reprodutibilidade dos Testes , Microtomografia por Raio-XRESUMO
PURPOSE: To three-dimensionally evaluate the internal fit at the implant-abutment interface of abutments fabricated with different workflows using a combination of the silicone replica technique and microcomputed tomography (µCT). MATERIALS AND METHODS: Thirty abutments were fabricated to restore internal-connection implants and were divided into three groups according to fabrication method: (1) full digital (abutment machined using CAD/CAM system); (2) Ti-Base (prefabricated standard Ti-Base abutments); and (3) UCLA (UCLA-type abutments) (n = 10/group). Linear and volume measurements were performed to assess the internal misfit using a silicone replica of the implant-abutment interface misfit area, which was three-dimensionally reconstructed after µCT. The internal discrepancies in three different regions of interest (Gapsuperior, Gapmarginal, and Gapcenter) were assessed. Data were statistically evaluated using ANOVA and Tukey test (P < .05). RESULTS: Ti-Base and UCLA abutments presented significantly lower misfit volume (0.49 mm3, 95% CI: ± 0.045 mm3 and 0.48 mm3, 95% CI: ± 0.045 mm3, respectively) and mean internal gap (25.20 µm, 95% CI: ± 3.14 µm and 27.97 µm, 95% CI: ± 3.14 µm, respectively) than the full digital group (0.70 mm3, 95% CI: ± 0.045 mm3; 34.90 µm, 95% CI: ± 3.14 µm) (P < .001), but did not differ from each other (P = .825). While Gapcenter was significantly higher in the full digital group (P < .001), Gapsuperior and Gapmarginal did not demonstrate significant differences among groups. All regions were statistically similar within groups, except for Gapcenter in the full digital group, which exhibited higher mean values compared to the other regions (P = .000). The 3D measurements for quantification of internal discrepancy were strongly associated with the 2D measurements. CONCLUSION: Ti-Base and UCLA abutments exhibited better internal fit at the implant-abutment interfaces compared to a fully digitalized workflow (CAD/CAM custom abutments).
Assuntos
Dente Suporte , Implantes Dentários , Desenho Assistido por Computador , Titânio , Microtomografia por Raio-XRESUMO
OBJECTIVE: An important factor affecting the biomechanical behavior of implant-supported reconstructions is the implant-abutment misfit. This study evaluated the misfit between Ti-Base abutments and implants by means of polyvinyl siloxane replica technique using microcomputed tomography (µCT). METHODOLOGY: Volumetric and linear (central and marginal) gaps of four Ti-base abutments (n=10/group): (i) Odontofix LTDA (OD), (ii) Singular Implants (SING), (iii) EFF Dental Components (EFF), and (iv) Control Group (S.I.N implants) compatible with an implant system (Strong SW, S.I.N Implants) were measured using µCT reconstructed polyvinyl siloxane replicas. RESULTS: The results showed significantly lower volume gap for Control S.I.N (0.67±0.29 mm3) and SING (0.69±0.28 mm3) Ti-base abutments relative to OD (1.42±0.28 mm3) and EFF groups (1.04±0.28 mm3) (p<0.033), without significant difference between them (p=0.936). While gap values were homogenous in the central region, EFF presented a significantly higher marginal gap. Accordingly, the Control S.I.N and Singular Ti-base abutments showed improved volumetric and marginal fit relative to Odontofix and EFF. CONCLUSION: The method of manufacturing abutments influenced the misfit at the implant-abutment interface.
Assuntos
Dente Suporte , Implantes Dentários , Projeto do Implante Dentário-Pivô , Técnicas de Réplica , Titânio , Microtomografia por Raio-XRESUMO
IMPACT STATEMENT: The various roles played by brain-derived neurotrophic factor (BDNF) in a multitude of tissues and at different scenarios have rendered BDNF a favorable candidate for improving tissue regeneration. Although the tested formulations of BDNF quantitatively regenerate tissue to a level similar to control groups, it resulted in significantly more instances of full regeneration.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/farmacologia , Colágeno/farmacologia , Periodonto/fisiologia , Regeneração/fisiologia , Animais , Regeneração Óssea/efeitos dos fármacos , Cemento Dentário/efeitos dos fármacos , Cemento Dentário/fisiologia , Cães , Epitélio/efeitos dos fármacos , Feminino , Imageamento Tridimensional , Periodonto/diagnóstico por imagem , Periodonto/efeitos dos fármacos , Microtomografia por Raio-XRESUMO
OBJECTIVE: To evaluate the reliability and failure mode of zirconia-reinforced lithium silicate (ZLS) molar crowns of different thicknesses. METHODS: Monolithic ZLS molar crowns (0.5mm, 1.0mm, and 1.5 mm thickness) were modeled and milled using a CAD/CAM system (n = 21/group). Crowns were cemented on dentin-like epoxy resin replicas with a resin cement. The specimens were subjected to single load-to-failure test for step-stress profiles designing. Mouth-motion step-stress accelerated-life test was performed under water by sliding an indenter 0.7 mm lingually down on the distobuccal cusp until specimen fracture or suspension. Use level probability Weibull curves and reliability were calculated and plotted. Polarized-light optical microscope and scanning electron microscope (SEM) were used to characterize fracture patterns. RESULTS: Irrespective of crown thickness, beta (ß) values were higher than 1 and fatigue accelerated failures. While 0.5 mm ZLS crowns exhibited a significant reduction in the probability of survival at 200N, 300N and 400 N mission loads (69%, 41% and 19%, respectively), no significant difference was observed between 1.0 mm and 1.5 mm crowns. Both thicknesses have maintained the survivability at approximately 90%. Failure primarily comprised bulk fracture where radial cracks originated from the cementation surface beneath the indenter loading trail and propagated towards the cervical margin. SIGNIFICANCE: 1.5 mm- and 1.0 mm-thickness monolithic ZLS crowns presented higher probability of survival compared to 0.5 mm crowns. Bulk fracture was the chief failure mode, regardless of thickness.
Assuntos
Porcelana Dentária , Lítio , Cerâmica , Desenho Assistido por Computador , Coroas , Planejamento de Prótese Dentária , Falha de Restauração Dentária , Análise do Estresse Dentário , Teste de Materiais , Reprodutibilidade dos Testes , Silicatos , ZircônioRESUMO
OBJECTIVE: Since the transmittance of ceramics can influence the degree of conversion (DC) of resin cements, ceramics composition and shade should be considered in the selection of resin cement. This in vitro study aimed to evaluate the effect of the transmittance of different composition, opacities and shades of ceramics on the degree of conversion of two dual-cured resin cements. METHODOLOGY: Sixty discs were prepared from low translucency (LT) and medium opacity (MO) lithium disilicate ceramic, and zirconia ceramic (Z). Each group was subdivided into 5 subgroups (n=4) in shades A2, A3.5, B2, C2 and D3. The transmittance measurement was performed in a spectrophotometer. The Variolink II and Rely X U200 resin cements were photoactivated by LED (1400 mW/cm2) for 40 s through the ceramic discs and without the discs (control group). The DC was measured with infrared FTIR spectroscopy, immediately after light activation. Data were analyzed with Kruskall-Wallis and one-way ANOVA, following post-hoc comparisons by Tukey test and Pearson's correlation test (P<0.05). RESULTS: LT ceramic exhibited higher transmittance values compared to MO and Z ceramics. LTA2 and LTB2 showed statistically higher transmittance values compared to MOA2, MOA3.5 and ZA3.5. For Variolink II, the ceramic interposition did not influence the DC, since there were no statistical differences between groups with ceramic interposition and the control group. For Rely X U200 cement, the interposition of some ceramics types/shades (LTA3.5, MOA2, MOA3.5 and ZA3.5) significantly decreased the DC values compared to control group. A positive correlation was found between the ceramic transmittance and DC values of both tested cements. Conclusions. The transmittance and DC values of the cements were influenced by composition and shades of the ceramics. The higher the transmittance of ceramics, the higher the DC values for both cements.
Assuntos
Porcelana Dentária/química , Cimentos de Resina/química , Zircônio/química , Análise de Variância , Lâmpadas de Polimerização Dentária , Cura Luminosa de Adesivos Dentários , Teste de Materiais , Transição de Fase , Polimerização , Valores de Referência , Reprodutibilidade dos Testes , Espectrofotometria/métodos , Estatísticas não ParamétricasRESUMO
O desenvolvimento e a popularização de técnicas operatórias associadas aos materiais odontológicos propiciaram a transformação das condições de saúde bucal em reabilitações estéticas. O objetivo deste estudo foi revisar a literatura acerca da utilização do dissilicato de lítio e de zircônias estabilizadas na fase cúbica em restaurações monolíticas. As bases de dados utilizadas foram Lilacs, Pubmed/Medline, Scielo e ScienceDirect, cruzando os seguintes descritores em língua inglesa: "Zirconium", "Yttrium", "CAD-CAM", "Ceramics", "Dental Porcelain" e "Material Resistance". As técnicas restauradoras indiretas monolíticas com as cerâmicas odontológicas atreladas ao uso da tecnologia CAD/CAM possuem diversas vantagens a curto e a longo prazo. O dissilicato de lítio e as zircônias de alta translucidez estabilizadas na fase cúbica são materiais atuais e de constante evolução na pesquisa odontológica devido ao seu comportamento mecânico, biológico, aspectos ópticos e estéticos, garantindo seu uso como materiais de excelência nas reabilitações estético-funcionais.
The development and popularization of surgical techniques associated with dental materials led to the transformation of oral health conditions into aesthetic rehabilitation. The aim of this study was to review the literature on the use of lithium disilicate and cubic phase stabilized zirconia in monolithic restorations. The databases used were Lilacs, Pubmed/Medline, Scielo and ScienceDirect, crossing the following descriptors in English: "Zirconium", "Yttrium", "CAD- CAM", "Ceramics", "Dental Porcelain" and "Material Resistance". Monolithic indirect restorative techniques with dental ceramics coupled with the use of CAD/ CAM technology have several short-and long-term advantages. Lithium disilicate and high translucency zirconia stabilized in the cubic phase are current materials and constantly evolving in dental research due to their mechanical behavior, biological, optical and aesthetic aspects, ensuring their use as materials of excellence in aesthetic and functional rehabilitation.
RESUMO
Abstract An important factor affecting the biomechanical behavior of implant-supported reconstructions is the implant-abutment misfit. Objective: This study evaluated the misfit between Ti-Base abutments and implants by means of polyvinyl siloxane replica technique using microcomputed tomography (μCT). Methodology: Volumetric and linear (central and marginal) gaps of four Ti-base abutments (n=10/group): (i) Odontofix LTDA (OD), (ii) Singular Implants (SING), (iii) EFF Dental Components (EFF), and (iv) Control Group (S.I.N implants) compatible with an implant system (Strong SW, S.I.N Implants) were measured using μCT reconstructed polyvinyl siloxane replicas. Results: The results showed significantly lower volume gap for Control S.I.N (0.67±0.29 mm3) and SING (0.69±0.28 mm3) Ti-base abutments relative to OD (1.42±0.28 mm3) and EFF groups (1.04±0.28 mm3) (p<0.033), without significant difference between them (p=0.936). While gap values were homogenous in the central region, EFF presented a significantly higher marginal gap. Accordingly, the Control S.I.N and Singular Ti-base abutments showed improved volumetric and marginal fit relative to Odontofix and EFF. Conclusion: The method of manufacturing abutments influenced the misfit at the implant-abutment interface.
Assuntos
Implantes Dentários , Dente Suporte , Titânio , Técnicas de Réplica , Microtomografia por Raio-X , Projeto do Implante Dentário-PivôRESUMO
Abstract Objective Since the transmittance of ceramics can influence the degree of conversion (DC) of resin cements, ceramics composition and shade should be considered in the selection of resin cement. This in vitro study aimed to evaluate the effect of the transmittance of different composition, opacities and shades of ceramics on the degree of conversion of two dual-cured resin cements. Methodology Sixty discs were prepared from low translucency (LT) and medium opacity (MO) lithium disilicate ceramic, and zirconia ceramic (Z). Each group was subdivided into 5 subgroups (n=4) in shades A2, A3.5, B2, C2 and D3. The transmittance measurement was performed in a spectrophotometer. The Variolink II and Rely X U200 resin cements were photoactivated by LED (1400 mW/cm2) for 40 s through the ceramic discs and without the discs (control group). The DC was measured with infrared FTIR spectroscopy, immediately after light activation. Data were analyzed with Kruskall-Wallis and one-way ANOVA, following post-hoc comparisons by Tukey test and Pearson's correlation test (P<0.05). Results LT ceramic exhibited higher transmittance values compared to MO and Z ceramics. LTA2 and LTB2 showed statistically higher transmittance values compared to MOA2, MOA3.5 and ZA3.5. For Variolink II, the ceramic interposition did not influence the DC, since there were no statistical differences between groups with ceramic interposition and the control group. For Rely X U200 cement, the interposition of some ceramics types/shades (LTA3.5, MOA2, MOA3.5 and ZA3.5) significantly decreased the DC values compared to control group. A positive correlation was found between the ceramic transmittance and DC values of both tested cements. Conclusions. The transmittance and DC values of the cements were influenced by composition and shades of the ceramics. The higher the transmittance of ceramics, the higher the DC values for both cements.
Assuntos
Zircônio/química , Cimentos de Resina/química , Porcelana Dentária/química , Valores de Referência , Espectrofotometria/métodos , Teste de Materiais , Reprodutibilidade dos Testes , Análise de Variância , Estatísticas não Paramétricas , Transição de Fase , Cura Luminosa de Adesivos Dentários , Lâmpadas de Polimerização Dentária , PolimerizaçãoRESUMO
As recessões gengivais são encontradas com bastante frequência na população, gerando, em muitos casos, incômodo estético. Sensibilidade radicular também tem sido relatada, além de maior predisposição à cárie e às lesões não cariosas de abrasão e erosão na superfície radicular desnuda. A fim de alcançar um recobrimento radicular satisfatório, muitas técnicas têm sido propostas, dentre elas os enxertos gengivais livres, enxertos gengivais pediculados ou a associação de ambos. O presente artigo teve por objetivo relatar um caso clínico de recobrimento radicular através da técnica de deslize lateral do retalho associada ao enxerto de tecido conjuntivo subepitelial. O acompanhamento clínico ao longo de um ano mostrou a ocorrência de creeping attachment.
The gingival recessions are found very frequently in the population, generating in many cases, aesthetic complaint. Root sensitivity has also been reported, beyond greater predisposition to caries and non-carious lesions of abrasion and erosion on the denuded root surface. In order to achieve satisfactory root coverage, many techniques have been proposed, among them the free gingival grafts, pedicled gingival grafts or a combination of both. This article aims to report a case of root coverage using the technique of laterally positioned flap associated with the subepithelial connective tissue graft. The one-year clinical follow-up showed the occurrence of creeping attachment.