El material restaurador ideal en la era de la odontología de invasión mínima. Rescatando al oro directo / The ideal restorative material at the minimal invasive dentistry era. Rescuing direct gold

Los logros de los avances obtenidos en el manejo actual de la caries han dado la oportunidad a los odontólogos de detectar lesiones de caries en sus estadios incipientes. A pesar de la existencia de una gran variedad de materiales restauradores directos disponibles en el mercado actual y que pueden utilizarse para restaurar lesiones pequeñas de caries, el material que tiene más posibilidades de éxito para este tipo de lesiones es sin duda alguna el oro cohesivo, también conocido como oro directo (AU)

The goals obtained with the current management of dental caries has given the dentists the opportunity to detect incipient caries lesions in early stages. Although, the current existence of a great variety of direct restorative materials available in the market to restore small caries lesions, the material that may show better success for these type of lesions, is without any doubt: the gold foil or direct gold (AU)

Wear Evaluation of Prosthetic Materials Opposing Themselves.

The purpose of the present in vitro study was to compare the two-body wear resistance of a type 3 gold alloy (Aurocast8), two lithium disilicate glass ceramics (IPS e.max CAD and IPS e.max Press), a heat-pressed feldspathic porcelain (Cerabien ZR Press), an yttria-stabilized tetragonal zirconia polycrystal ceramic (Katana Zirconia ML), and three heat-cured composite resins (Ceram.X Universal, Enamel Plus Function, and Enamel Plus HRi) opposing antagonistic cusps made out of the same restorative materials. Ten 6-mm-thick samples and 10 cusp-shaped abraders were manufactured with each test material (n=10) according to standard laboratory procedures. All sample/antagonist pairs made out of the same material were subjected to a two-body wear test in a dual-axis chewing simulator for up to 120,000 loading cycles. The total vertical wear (mm) and the total volumetric loss (mm3) for each sample/antagonist pair were calculated. Data were statistically analyzed using one-way analysis of variance tests. The total vertical wear for the gold alloy was not significantly different compared to Ceram.X Universal, Enamel Plus Function, IPS e.max CAD, and Cerabien ZR Press. Significantly increased wear values were observed for Enamel Plus HRi and IPS e.max Press. The lowest values for total vertical wear and volumetric loss were recorded on the monolithic zirconia.

Clinical evaluations of cast gold alloy, machinable zirconia, and semiprecious alloy crowns: A multicenter study.

STATEMENT OF PROBLEM: Few studies have compared the marginal and internal fits of crowns fabricated from machinable palladium-silver-indium (Pd-Ag-In) semiprecious metal alloy. PURPOSE: The purpose of this clinical study was to evaluate and compare the marginal and internal fits of machined Pd-Ag-In alloy, zirconia, and cast gold crowns. MATERIAL AND METHODS: A prospective clinical trial was performed on 35 participants and 52 abutment teeth at 2 centers. Individuals requiring prosthetic restorations were treated with gold alloy or zirconia crowns (2 control groups) or Pd-Ag-In alloy crowns (experimental group). A replica technique was used to evaluate the marginal and internal fits. The buccolingual and mesiodistal cross-sections were measured, and a noninferiority comparison was conducted. RESULTS: The mean marginal gaps were 68.2 µm for the gold crowns, 75.4 µm for the zirconia crowns, and 76.9 µm for the Pd-Ag-In alloy crowns. In the 5 cross-sections other than the distal cross-section, the 2-sided 95% confidence limits for the differences between the Pd-Ag-In alloy crowns and the 2 control groups were not larger than the 25-µm noninferiority margin. The control groups displayed smaller internal gaps in the line angle and occlusal spaces compared with the Pd-Ag-In crown group. CONCLUSION: The marginal gaps of machinable Pd-Ag-In alloy crowns did not meet the noninferiority criterion in the distal margin compared with zirconia and gold alloy crowns. Nonetheless, all 3 crowns had clinically applicable precision.

Multicenter cohort study to assess the impact of a silver-alloy and hydrogel-coated urinary catheter on symptomatic catheter-associated urinary tract infections.

PURPOSE: The purpose of this study was to determine the effect of a silver-alloy hydrogel catheter on symptomatic catheter-associated urinary tract infections (CAUTIs). DESIGN: Multicenter before-after non-randomized cohort study. SUBJECTS AND SETTING: Seven acute care hospitals ranging in size from 124 to 607 beds participated in this study. The study population included adult patients with a positive urine culture 2 or more days after admission, who underwent Foley catheterization. METHODS: Catheter-associated urinary tract infection surveillance was conducted at each hospital for at least 3 months during the use of a standard catheter and 3 months during the use of the silver-alloy hydrogel catheter. Both the National Healthcare Safety Network (NHSN) surveillance and a clinical definition of CAUTI were used for rate calculation. RESULTS: A 47% relative reduction in the CAUTI rate was observed with the silver-alloy hydrogel catheter compared to the standard catheter when both infection definitions were used (0.945/1000 patient days vs 0.498/1000 patient days) (odds ratio = 0.53; P < .0001; 95% CI: 0.45-0.62). When only NHSN-defined CAUTIs were considered, a 58% relative reduction occurred in the silver-alloy hydrogel period (0.60/1000 patient days vs 0.25/1000 patient days) (odds ratio = 0.42; P < .0001; 95% CI: 0.34-0.53). Antimicrobial days for CAUTIs decreased from 1165 (standard catheter period) to 406 (silver-alloy hydrogel period). CONCLUSIONS: Use of a silver-alloy hydrogel urinary catheter reduced symptomatic CAUTI occurrences as defined by both NHSN and clinical criteria.

Stress distribution in molars restored with inlays or onlays with or without endodontic treatment: a three-dimensional finite element analysis.

STATEMENT OF PROBLEM: Previous research into the strength of endodontically treated or vital teeth restored with inlays or onlays has not determined which restoration method and material provide the most favorable stress distribution upon loading. PURPOSE: The purpose of this study was to calculate the von Mises stresses in a mandibular first molar using a 3-dimensional (3-D) finite element model. Models compared endodontically treated and vital teeth, a variety of restorative materials, and the use of either inlays or onlays to restore teeth. MATERIAL AND METHODS: Four 3-D models of mandibular first molars were created: (1) the IV group (inlay restored, vital pulp); (2) the OV group (onlay restored, vital pulp); (3) the IE group (inlay restored, endodontically treated); and (4) the OE group (onlay restored, endodontically treated). In each group, 3 types of restorative material were tested: (1) composite resin, (2) ceramic, and (3) gold alloy. The materials had elastic moduli of 19 GPa, 65 GPa, and 96.6 GPa, respectively. Each model was subjected to a force of 45 N directed to the occlusal surface, applied either vertically or laterally (45 degrees obliquely). The stresses occurring in dentin tissue were calculated. The stress distribution patterns and the maximum von Mises stresses were calculated and compared. RESULTS: The different restorative materials exhibited similar stress distribution patterns under identical loading conditions. In each group, the gold-restored tooth exhibited the highest von Mises stress, followed by ceramic and composite resin. The maximum von Mises stress in dentin was found in the IE group (16.73 MPa), which was 5 times higher than the highest value found in the OV group (2.96 MPa). The highest stresses, which occurred at the floor of the preparation and the cervical region in dentin, were in the IE group. The stress concentration area in the IE group was also larger. CONCLUSIONS: The results indicate that endodontic treatment caused higher stress concentration in dentin compared with vital teeth, but that proper restoration can minimize internal stresses. In the models, the von Mises stress values increased with the increasing elastic modulus of the restorative material. Composite resin onlays showed the best performance overall in minimizing internal stresses. As internal stresses are indicated as a prime failure mechanism of the restoration, composite resin onlays are expected to better restore structural integrity.

[The mechanic retention of the casting post with keeper in magnetic retentor overdenture].

PURPOSE: To reduce the cost of the fabrication of the magnetic retentor,and meet the clinical requirements, nonprecious alloy such as Co-Cr alloy was used to fabricate the magnetic retentor in overdenture , instead of the precious alloy. METHODS: A mandibular canine was chosen for root canal preparation in vitro. Thirty two resin posts were made in the same root canal with self-curing resin. The 32 resin posts were randomly divided into 4 groups. Among them,2 groups were fabricated with soft Co-Cr alloy, gold alloy(55.6%Au) respectively in vitro. Another 2 groups were fabricated with Co-Cr alloy, and the surface of the root casting post with keeper were treated with gold deposit and gold coating technique. After that, test of dislodgment force was done and one-way ANOVA was performed with SAS 6.2 software package. RESULTS: The dislodgment force of the root casting posts with keeper which were fabricated with the Co-Cr, Ni-Cr, and gold alloy had significant difference(P<0.01). While after surface treatment by gold deposit and gold coating technique on root casting posts with keeper that were fabricated with Co-Cr and Ni-Cr alloy, there was no significant difference in dislodgment force, compared with that of gold alloy. CONCLUSIONS: After surface treatment of the root casting posts with keeper which were fabricated with the Co-Cr and Ni-Cr alloy, the same clinical retentive effect can be obtained as the one that was fabricated with gold alloy.

Long-term survival estimates of cast gold inlays and onlays with their analysis of failures.

The aim of the present study was to assess the clinical behaviour of cast gold restorations with respect to define a gold control against current and future ceramic and composite restorations. The study sample included 50 patients with 303 cast gold restorations. All restorations were cemented with a non-adhesive technique. A total of 303 restorations were evaluated clinically and radiographically using modified United States Public Health Service criteria. Restorations recorded as having an A- or a B-rating were defined as successful. Of the 303 restorations, 42 were judged as failures, which resulted in a failure rate of 13.8% for a mean observation time (+/- s.d.) of 18.7 ( +/- 9.5) years. The estimated Kaplan-Meier survival rates (s.e.) were 96.1% (+/- 1.1%) at 10 years, 87.0% (+/- 2.2%) at 20 years and 73.5% (+/- 5.4%) at 30 years. In total, biological reasons were counted 25 times in comparison to 17 technical reasons for those 42 failed cast gold restorations, with 17 secondary caries (40%) as the most common biological reason and with 13 retention losses (31%) as the most common technical reason. The endodontically treated tooth was exclusively identified as a risk factor. The restoration type (inlay versus onlay) did not influence the survival rate.

Tratamiento de una mordida abierta anterior por medio de restauraciones onlay. Reporte de un caso / Treatment of an anterior openbite by means of onlay restorations. Report of a case

Se describe el caso clínico de la resolución de una mordida abierta anterior, diagnosticada por la elaboración de un montaje en articulador semiajustable bajo la técnica modificada del modelo seccionado de Kennedy, en donde se logró el acople de dientes anteriores y su participación en movimientos funcionales mandibulares, por medio de la colocación de cuatro restauraciones onlay en molares superiores posteriormente a la extracción de terceros molares mandibulares y maxilares erupcionados

Resposta do tecido conjuntivo subcutâneo de rato após implantes das ligas restauradoras odontológicas: Duracast, Idealoy, cromo-cobalto e ouro / Reaction of rat subcutaneous connective tissue followed by implants of dental restorative alloys (Duracast, Idealoy, Crom-cobalt alloy and gold alloy)

A presente pesquisa consistiu em observar a resposta do tecido conjuntivo subcutâneo de rato após implantes das ligas restauradoras odontológicas à base de cobre-alumínio (Duracast e Idealoy), de ligas de ouro, de cromo-cobalto e parafina. A avaliaçäo histológica foi realizada após implantes de 10, 30 e 80 dias dos materiais testados, em um total de 30 ratos

[Pharmacokinetics of gold after administration of aurokeratinate (author's transl)]. / Das pharmakokinetische Verhalten von Gold nach Gabe von Aurokeratinat.

Aurokeratinate (Auro-Detoxin) was administered intramuscularly to patients with chronic rheumatoid arthritis, using two different dosage schedules and measuring serum gold concentration. (1) Using slowly rising doses (as generally practised) the gold level gradually rose to 3.2 microgram/ml after four weeks (before the ninth injection), without reaching cumulation equilibrium. Elimination from serum occurred during this phase, with a half-life of 3-5 days. When treatment was continued at about 25 mg gold twice weekly, the cumulation equilibrium was reached with a minimal value at 3.5 microgram/ml and a maximal one of 6 microgram/ml, elimination half-life then being increased to nine days. During the subsequent maintenance treatment with 65 mg gold once a month the serum-gold concentration fell to about 1 microgram/ml, maximal values being about 6 microgram/ml, with an elimination half-life of 11 days. (2) With a constant dose of about 25 mg gold twice weekly, cumulation equilibrium was reached after two weeks (3.4 microgram/ml before the fifth injection), while on 50 mg gold every 14 days as maintenance dose the serum concentration was between 2 microgram/ml minimally and 6 microgram/ml maximally. At the modified dosage the drug was well tolerated.