RESUMEN
OBJECTIVES: This study determined the two-body wear and toothbrushing wear parameters, including gloss and roughness measurements and additionally Martens hardness, of nine aesthetic CAD/CAM materials, one direct resin-based nanocomposite plus that of human enamel as a control group. MATERIALS AND METHODS: Two-body wear was investigated in a computer-controlled chewing simulator (1.2 million loadings, 49N at 1.7Hz; 3000 thermocycles 5/50°C). Each of the 11 groups consisted of 12 specimens and 12 enamel antagonists. Quantitative analysis of wear was carried out with a 3D-surface analyser. Gloss and roughness measurements were evaluated using a glossmeter and an inductive surface profilometer before and after abrasive toothbrushing of machine-polished specimens. Additionally Martens hardness was measured. Statistically significant differences were calculated with one-way ANOVA (analysis of variance). RESULTS: Statistically significant differences were found for two-body wear, gloss, surface roughness and hardness. Zirconium dioxide ceramics showed no material wear and low wear of the enamel antagonist. Two-body wear of CAD/CAM-silicate and -lithium disilicate ceramics, -hybrid ceramics and -nanocomposite as well as direct nanocomposite did not differ significantly from that of human enamel. Temporary polymers showed significantly higher material wear than permanent materials. Abrasive toothbrushing significantly reduced gloss and increased roughness of all materials except zirconium dioxide ceramics. Gloss retention was highest with zirconium dioxide ceramics, silicate ceramics, hybrid ceramics and nanocomposites. Temporary polymers showed least gloss retention. Martens hardness differed significantly among ceramics, between ceramics and composites, and between resin composites and acrylic block materials as well. CONCLUSIONS: All permanent aesthetic CAD/CAM block materials tested behave similarly or better with respect to two-body wear and toothbrushing wear than human enamel, which is not true for temporary polymer CAD/CAM block materials. Ceramics show the best gloss retention compared to hybrid ceramics, composites and acrylic polymers.
Asunto(s)
Diseño Asistido por Computadora , Materiales Dentales/química , Pulido Dental/métodos , Alisadura de la Restauración Dental , Restauración Dental Permanente/métodos , Análisis del Estrés Dental/métodos , Dureza , Ensayo de Materiales , Propiedades de SuperficieRESUMEN
The "biogeneric tooth model" can be used for computer-aided design (CAD) of the occlusal surface of dental restorations. From digital 3D-data, it automatically retrieves a morphology matching the natural surface left after preparation. This study evaluates the potential of this method for generating well-matched and well-adjusted CAD/computer-aided manufacturing (CAM) fabricated partial crowns. Twelve models with partial crown preparations were mounted into an articulator. Partial crowns were designed with the Cerec 3D CAD software based on the biogeneric tooth model (Biog.CAD) and, for control, with a conventional data-based Cerec 3D CAD software (Conv.CAD). The design time was measured, and the naturalness of the morphology was visually assessed. The restorations were milled, cemented on the models, and the vertical discrepancy and the time for final occlusal adjustment were measured. The Biog.CAD software offered a significantly higher naturalness (up to 225 to 11 scores) and was significantly faster by 251 (± 78) s in designing partial crowns (p < 0.01) compared to Conv.CAD software. Vertical discrepancy, 0.52 (± 0.28) mm for Conv.CAD and 0.46 (± 0.19)mm for Biog.CAD, and occlusal adjustment time, 118 (± 132)s for Conv.CAD and 102 (± 77)s for Biog.CAD, did not differ significantly. In conclusion, the biogeneric tooth model is able to generate occlusal morphology of partial crowns in a fully automated process with higher naturalness compared to conventional interactive CAD software.
Asunto(s)
Diseño Asistido por Computadora , Coronas , Diseño de Prótesis Dental , Modelos Dentales , Modelos Teóricos , Adolescente , Adulto , Porcelana Dental , Femenino , Humanos , Modelos Lineales , Masculino , Ajuste Oclusal , Programas Informáticos , Estadísticas no Paramétricas , Encuestas y Cuestionarios , Factores de Tiempo , Preparación Protodóncica del Diente , Dimensión Vertical , Adulto JovenRESUMEN
PURPOSE: One-visit in-office CAD/CAM fabrication of esthetic ceramic crowns as a superstructure for posterior implants is quite new. The aim of the study was to evaluate the strength of esthetic ceramic CAD/CAM crowns with varied occlusal thickness and seated with adhesive and nonadhesive cements on titanium and zirconia abutments. MATERIALS AND METHODS: Esthetic ceramic CAD/CAM-generated molar crowns (n = 15 per group) with occlusal thicknesses of 0.5 mm and 1.5 mm were seated on titanium (1) and zirconia (2) abutments: noncemented (a) and with nonadhesive cement (b) or 2 adhesive resin-based cements (c) and (d). In addition, 15 molar crowns with 5.5-mm occlusal thickness were seated on short zirconia abutments (3) using cements (c) and (d). All crowns had the identical occlusal morphology and were loaded with a crosshead speed of 0.5 mm/min until fracture. Load data were analyzed using 2-way ANOVA, the Scheffé test, and Weibull probability of failure analysis. RESULTS: Fracture loads of 1.5-mm occlusal thickness crowns (a, b, c, d) were higher (P < .001) than those of 0.5-mm crowns (except for group ld). Occlusal 5.5-mm crowns on short zirconia abutments had similar (2c) or less (2d) strength than the respective 1.5-mm crowns. Nonadhesive crowns (1b, 2b) were weaker (P < .001) than adhesive crowns (1c, 1d, 2c, 2d). Fracture loads of 0.5- and 1.5-mm crowns were significantly higher on titanium than on zirconia abutments with both cements. Adhesive cement d generally showed higher fracture loads than c on both titanium and zirconia. CONCLUSION: Esthetic ceramic CAD/CAM molar implant crowns gained high strength with adhesive cements on both titanium and zirconia implant abutments compared to nonadhesive cementation.
Asunto(s)
Diseño Asistido por Computadora , Coronas , Porcelana Dental , Diseño de Prótesis Dental , Prótesis Dental de Soporte Implantado , Análisis de Varianza , Cementación/métodos , Pilares Dentales , Aleaciones Dentales , Análisis del Estrés Dental , Estética Dental , Diente Molar , Estadísticas no Paramétricas , Análisis de Supervivencia , Titanio , CirconioRESUMEN
The objective of this study was to evaluate, by scanning electron microscopy, the marginal and internal fit of all-ceramic three-unit fixed partial denture (FPD) frames fabricated by computer-assisted design/computer-aided machining (CAD/CAM) and CAM techniques using blocks of infiltration ceramic, high-strength yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) zirconia sinter ceramic, high-strength dense sintered Y-TZP zirconia ceramic, and glass ceramic. Slip-cast infiltration ceramic was used as a traditional control. The cementation interface widths of the FPD frame copings on butt (A) shoulders of Cerec In-Ceram zirconia (A1, 53 +/- 17 microm) were smaller than those of slip-cast In-Ceram zirconia (A6, 113 +/- 25 microm). Cerec Y-TZP zirconia (A2, 53 +/- 9 pm) and DCS Y-TZP zirconia (A4, 32 +/- 6 microm) interfaces were both significantly smaller than those of Cercon Y-TZP zirconia (A5, 120 +/- 6 microm). Internally, A2 (103 +/- 14) interfaces were smaller than A4 interfaces (144 +/- 15 microm). On chamfer shoulders (B), Cerec Y-TZP zirconia (B1, 71 +/- 5 microm) interfaces were smaller than Cercon interfaces (B2, 129 +/- 38 microm); internally, B1 (80 +/- 11 microm) interfaces were smaller than B2 interfaces (130 +/- 12 microm). CAD/CAM produced better marginal and internal accuracy of fit compared to slip casting and CAM techniques.
Asunto(s)
Diseño Asistido por Computadora , Porcelana Dental , Diseño de Prótesis Dental , Dentadura Parcial Fija , Análisis de Varianza , Adaptación Marginal Dental , Ajuste de Prótesis , Estadísticas no Paramétricas , Itrio , CirconioRESUMEN
BACKGROUND AND OVERVIEW: Early in 1980, the author anticipated the attraction of restoring posterior teeth with tooth-colored material. He conducted studies and developed the clinical concept of bonded ceramic inlays, at the same time raising the issue of the fast fabrication of the ceramic restorations. The author developed plans for in-office computer-aided design/computer-aided manufacturing (CAD/CAM) fabrication of ceramic restorations specifically to enable the dentist to complete one or multiple ceramic restorations chairside, in a single appointment. The initial concept comprised a small mobile CAD/CAM unit integrating a computer, keyboard, trackball, foot pedal and optoelectronic mouth camera as input devices, a monitor and a machining compartment. CEREC 3 (Sirona Dental Systems GmbH, Bensheim, Germany) divided the system into an acquisition/design unit and a separate machining unit. Three-dimensional software makes the handling illustrative and easy both in the office and in the laboratory. CONCLUSIONS: It appears that the CEREC CAD/CAM concept is becoming a significant part of dentistry. CLINICAL IMPLICATIONS: Sound knowledge of adhesive bonding and diligent planning are essential for the successful integration of CAD/CAM into clinical dental offices.
Asunto(s)
Cerámica/historia , Materiales Dentales/historia , Diseño de Prótesis Dental/historia , Restauración Dental Permanente/historia , Diseño Asistido por Computadora/historia , Diseño de Prótesis Dental/instrumentación , Restauración Dental Permanente/métodos , Historia del Siglo XX , HumanosRESUMEN
PURPOSE: To assess the accuracy of preparation surface area measurements (mm2) using the Cerec digital mouth camera in vitro and to analyze a collection of 514 Cerec camera in vivo optical impressions of preparations from 274 patients according to the size of preparation/bonding area (mm2) METHODS: The surface area (mm2) of model preparations with known dimensions namely of one occlusal (1) and one mesio-occluso-distal (2) cavity as well as of one central incisor (3) and one molar (4) crown preparation was calculated from linear (a) design dimensions, (b) slide-gauge and (c) coordinate-measuring-machine data as benchmark measurements and from repeated (n=10) (d) laser-scan (control), (e) Cerec-camera mounted on a support, (f) handheld Cerec-camera measurements. Data of (d), (e) and (f) was statistically analyzed. From a collection of data sets clinically recorded with the Cerec camera, the surface areas of 514 preparations from 274 patients were analyzed according to the type of tooth and type of preparation. RESULTS: Occlusal cavity mm2 data 1(d) 48 +/- 0.4, 1(e) 48 +/- 0.2, 1(f) 48 +/- 0.6 and mod cavity mm2 data 2(d) 137 +/- 2, 2(e) 138 +/- 1, 2(f) 138 +/- 4 did not differ between (d), (e) and (f) (P> 0.05) confirming the hypothesis for inlay cavities. Incisor crown preparation mm2 data 3(d) 82+0.4 differed (P< 0.001) from 3(e) 85 +/- 0.2 and 3(f) 85 +/- 0.6 as well as molar crown preparation mm2 data 4(d) 133 +/- 0.6 differed by 3.5% (P< 0.001) from 4(e) 137 +/- 0.4 and 4f) 138 +/- 1. Clinical cavity and crown preparation area data obtained from in vivo Cerec camera recordings differentiated between type of tooth and type of cavity. 2D data of "classic", "reduced" and "endo" type crown preparations did not differentiate clearly.
Asunto(s)
Cerámica , Incisivo/anatomía & histología , Diente Molar/anatomía & histología , Preparación Protodóncica del Diente/métodos , Terapia por Láser , Preparación Protodóncica del Diente/instrumentaciónRESUMEN
OBJECTIVES: This study evaluated the strength and fracture pattern of monolithic posterior CAD/CAM crowns hypothesizing that zinc-phosphate cemented lithium disilicate crowns might show the same fracture strength as adhesively cemented crowns. METHODS: Two sets of monolithic posterior crowns each with uniform occlusal and lateral wall thickness of 1.5mm were fabricated from three types of block ceramic (1) lithium disilicate glass, (2) leucite glass and (3) feldspathic ceramic using CEREC 3 CAD/CAM. Crowns (n = 15) of ceramics (1), (2) and (3) each were (A) zinc-phosphate cemented, (B) adhesively cemented on resin-based composite dies and loaded until fracture. Load data was analyzed using ANOVA and Scheffé tests. Crack pattern was evaluated on an additional three sample cross-sections for each group at start of fracture. RESULTS: Radial cracks originated early at the cementation interfaces and cone cracks were observed finally at the loading sites. Mean load values (SD) of A-crowns at fracture start/end (1) 807 (91) N/2082 (192) N; (2) 915 (193) N/1130 (166) N; (3) 985 (199) N/1270 (301) N were all significantly (P < 0.001) lower when compared to their B-crown analogs (1) 1456 (205) N/2389 (84) N; (2) 1684 (395) N/2469 (171) N; (3) 1548 (304) N/2392 (75) N, rejecting the authors hypothesis. A-1 crowns had significantly (P < 0.001) higher fracture load than A-2 and A-3 crowns. The A-1 crown fracture load data, even if significantly (P < 0.001) lower, came close to the B-1 values. SIGNIFICANCE: Adhesive cementation balanced the strength of weak ceramics with that of strong ceramic and recommended itself for leucite glass ceramic and feldspathic ceramic crowns. Zinc-phosphate cementation appeared feasible for lithium disilicate crowns.
Asunto(s)
Diseño Asistido por Computadora , Coronas , Porcelana Dental/química , Diseño de Prótesis Dental , Silicatos de Aluminio/química , Cementación/métodos , Cerámica/química , Recubrimiento Dental Adhesivo , Fracaso de la Restauración Dental , Vidrio/química , Humanos , Compuestos de Litio/química , Ensayo de Materiales , Compuestos de Potasio/química , Silicatos/química , Estrés Mecánico , Cemento de Fosfato de Zinc/químicaRESUMEN
PURPOSE: Adhesive cementation reduces the need for macroretentive preparation for crowns. This study investigated the survival and clinical rating of monolithic computer-aided design/manufacturing (CAD/CAM) ceramic crowns bonded to preparations with reduced macroretention, hypothesizing that adhesion would compensate for reduced retention geometry. MATERIALS AND METHODS: Two-hundred eight posterior CAD/CAM-generated crowns from feldspar block ceramic were adhesively bonded in 136 patients in three preparation groups: classic (100% stump height, n = 70); reduced (reduced stump height or irregular stump, n = 52); and endo (absent stump but pulp chamber retention cavity, n = 86). Crowns were examined at baseline and after 55 +/- 15 months using modified USPHS criteria. Plaque and bleeding of gingiva around the crowns were assessed. RESULTS: Cumulative Kaplan-Meier survival of crowns on premolars/molars was: classic = 97.0%/94.6%; reduced = 92.9%/92.1%; and endo = 68.8%/87.1%, confirming the hypothesis for classic, reduced, and endo molars as well as for classic and reduced premolars. A significant difference was found between classic and endo premolar crowns, rejecting the hypothesis for endo preparation on premolars. Plaque and bleeding indices were significantly lower for crowned teeth than for controls. CONCLUSION: The survival of classic and reduced crowns was rated adequate for premolars and molars. Endo preparation appeared acceptable for molar crowns but inadequate for premolar crowns.
Asunto(s)
Cementación , Cerámica/química , Diseño Asistido por Computadora , Coronas , Recubrimiento Dental Adhesivo , Retención de Prótesis Dentales , Preparación Protodóncica del Diente/métodos , Silicatos de Aluminio/química , Diente Premolar , Índice de Placa Dental , Porcelana Dental/química , Fracaso de la Restauración Dental , Recubrimientos Dentinarios/química , Estudios de Seguimiento , Hemorragia Gingival/clasificación , Humanos , Ensayo de Materiales , Diente Molar , Índice Periodontal , Técnica de Perno Muñón , Compuestos de Potasio/química , Estudios Prospectivos , Análisis de SupervivenciaRESUMEN
Anterior mono-ceramic (Mk II, n = 18) and ceramic core (In-Ceram Spinell, n = 18) crowns were CAD/CAM-fabricated using Vitablocs with the Cerec 2 CAD/CAM system and bonded in 24 patients. All crowns were rated using modified United States Public Health Services (USPHS) criteria at baseline and after a service time of 2-5 years. Survival of the crowns, regarding fracture, was analysed (Kaplan-Meier) after 44.7 +/- 10.3 months. Gingival health at crowns was assessed using plaque and bleeding scores. One core crown and one mono-ceramic crown had fractured after 42.5 months and 12 months, respectively, with survival rates of 91.7% for In-Ceram Spinell and 94.4% for Mk II; the difference was not statistically significant. Between baseline and follow-up examinations, non-significant shifts from A- to B-ratings occurred, particularly for marginal adaptation, for both crown types. Plaque and bleeding scores did not differ between the ceramic crown types but showed significantly less plaque and less bleeding at ceramic crowns than at control teeth at follow-up. The clinical performance of mono-ceramic crowns was judged to be similar to that of ceramic core crowns.
Asunto(s)
Cerámica/química , Diseño Asistido por Computadora , Coronas , Diseño de Prótesis Dental , Adulto , Anciano , Óxido de Aluminio/química , Silicatos de Aluminio/química , Materiales Dentales/química , Índice de Placa Dental , Porcelana Dental/química , Fracaso de la Restauración Dental , Femenino , Estudios de Seguimiento , Humanos , Modelos Lineales , Óxido de Magnesio/química , Masculino , Persona de Mediana Edad , Índice Periodontal , Compuestos de Potasio/química , Propiedades de Superficie , Análisis de SupervivenciaRESUMEN
The effect of hardware and software on the quality of Cerec all-ceramic partial crowns was investigated in this cross-sectional study. Partial crowns (n = 818) had been adhesively placed in 496 patients between 1993 and 1997 using Cerec 1 and Cerec 2 units (groups 1 and 2) as well as Cerec 2 with wall-spacing software (group 3). From each group, 25 randomly selected partial crowns were evaluated using modified United States Public Health Service (USPHS) criteria. Of these, 12 were randomly selected in each group, replicas taken and examined in a scanning electron microscope for marginal interfacial width and for continuous margin adaptation. Interfacial width of group 1 (308 +/- 95 micro m) was significantly larger than those of groups 2 (243 +/- 48 micro m) and 3 (207 +/- 63 micro m). Continuous margin adaptation at the tooth-luting composite and luting composite-restoration interfaces showed only minor differences in groups 1 (94.5 +/- 8% and 95.5 +/- 2%), 2 (98.1 +/- 1% and 97.5 +/- 1.4%) and 3 (96.8 +/- 3% and 96.8 +/- 2%). Pooled clinical rating was excellent or good at 97% for all groups, indicating acceptable restoration quality except for one breakage in group 1.
Asunto(s)
Diseño Asistido por Computadora , Coronas , Porcelana Dental , Diseño de Prótesis Dental , Adulto , Análisis de Varianza , Cementación , Cerámica , Adaptación Marginal Dental , Recubrimientos Dentinarios , Femenino , Humanos , Masculino , Microscopía Electrónica de Rastreo , Persona de Mediana Edad , Ajuste de Prótesis , Cementos de ResinaRESUMEN
PURPOSE: This study investigated fracture load of computer-aided design/manufacturing (CAD/CAM)-generated slot-inlay fixed partial dentures (FPD) machined from ceramic and composite. MATERIALS AND METHODS: Ninety slot-inlay FPDs were machined in groups of 15 specimens each using the same design on a Cerec 3 unit. Materials were assigned to groups: (1) Mk II feldspathic ceramic, (2) ProCAD glass-ceramic, (3) glass-ceramic 1, (4) glass-ceramic 2, (5) composite 1, and (6) composite 2. The slot-inlay FPDs were placed on models with two abutment teeth without cementation and loaded to fracture. For control, test bars (n = 15) were machined from each of the materials, and flexural strength was examined using three-point bending. Data were statistically analyzed using ANOVA and Scheffé tests. RESULTS: Fracture load of groups 4 (1,557 N, SD 236), 5 (1,048 N, SD 77), and 6 (1,512 N, SD 106) was significantly higher than that of groups 1 (652 N, SD 53) and 2 (773 N, SD 65). Flexural strength of group 4 (256 MPa, SD 20) was significantly higher than that of groups 1 (103 MPa, SD 6), 2 (127 MPa, SD 15), 3 (162 MPa, SD 32), 5 (178 MPa, SD 18), and 6 (170 MPa, SD 20). CONCLUSION: Fracture loads of glass-ceramic 2 and composite 2 appear adequate for CAD/CAM slot-inlay FPDs.
Asunto(s)
Diseño Asistido por Computadora , Diseño de Dentadura , Dentadura Parcial Fija , Incrustaciones , Silicatos de Aluminio/química , Análisis de Varianza , Cerámica/química , Resinas Compuestas/química , Pilares Dentales , Porcelana Dental/química , Fracaso de la Restauración Dental , Vidrio/química , Humanos , Ensayo de Materiales , Docilidad , Compuestos de Potasio/química , Estrés Mecánico , Soporte de PesoRESUMEN
PURPOSE: This study evaluated the clinical performance of posterior CAD/CAM-generated In-Ceram Alumina and In-Ceram Spinell core crowns. MATERIALS AND METHODS: Nineteen In-Ceram Spinell core crowns (four premolars and 15 molars) and 24 In-Ceram Alumina core crowns (two premolars and 22 molars) in 21 patients were examined using modified USPHS criteria at baseline and after a mean service time of 39 +/- 11 months. The crown copings were machined from Vitablocs In-Ceram Alumina and Vitablocs In-Ceram Spinell using the Cerec 2 CAD/CAM system. RESULTS: Two molar In-Ceram Alumina core crowns fractured after respective service times of 14 and 17 months in the same patient. The Kaplan-Meier survival rate regarding fracture of the ceramic was 92% for In-Ceram Alumina and 100% for In-Ceram Spinell. At the follow-up examination, 80% alpha ratings and 18% beta ratings for In-Ceram Alumina core crowns and 84% alpha ratings and 15% beta ratings for In-Ceram Spinell core crowns were recorded. CONCLUSION: Despite the two fractures, the clinical quality of CAD/CAM-generated In-Ceram Alumina and In-Ceram Spinell posterior crowns was excellent. Within the limitations of this study, both types of crowns appeared to be feasible.
Asunto(s)
Diseño Asistido por Computadora , Coronas , Porcelana Dental , Diseño de Prótesis Dental , Adulto , Anciano , Óxido de Aluminio , Diente Premolar , Fracaso de la Restauración Dental , Femenino , Humanos , Óxido de Magnesio , Masculino , Persona de Mediana Edad , Diente Molar , Análisis de SupervivenciaRESUMEN
An update is given on the research and development of chair-side all-ceramic CAD/CAM restorations. The Cerec CAD/CAM technology now has close to 8000 users worldwide. Recent improvements provide a sufficiently user-friendly handling of all components to accommodate the user with ordinary technical skills. CAD/CAM technology using non-metallic esthetic materials is increasingly gaining importance in restorative dentistry.