Biomedical subjects

Claus-Peter Ernst

Publications and source records attributed to Claus-Peter Ernst.

5 recordsLinked to original sources

PubMed2003

Two-year clinical performance of a packable posterior composite with and without a flowable composite liner.

The aim of the study was to evaluate the clinical performance of a packable fine hybrid dental composite (Prodigy Condensable) and the influence of the additional application of a flowable resin composite (Revolution, SDS Kerr) layer on marginal integrity after 2 years in stress-bearing posterior cavities according to the Ryge criteria. In 50 patients (40.5+/-17.5 years of age), 116 class II fillings (metal matrix system, glass ionomer-cement-base in 36%, rubberdam isolation in 70%) were placed, with at least two restorations per patient. The adhesive Optibond Solo Plus was used for all the restorations. In one of the two fillings in each patient, an additional layer of the flowable composite Revolution was applied in the entire cavity and separately light-cured. Baseline scores have been rated Alfa in > or =95% and Bravo in <5%. After 2 years, the results [%] of the Ryge evaluation for the two groups with/without the additional use of Revolution were: (1) Marginal Adaptation: Alfa:78/70, Bravo:16/27, Charlie:0/0, Delta:6/4; (2) Anatomic Form: Alfa:89/95, Bravo:6/2, Charlie:6/4; (3) Secondary Caries: Alfa:98/100, Bravo:2/0; (4) Marginal Discoloration: Alfa:76/68, Bravo:24/32, Charlie:0/0; (5) Surface: Alfa:90/91, Bravo:4/5, Charlie:0/0, Delta:6/4; (6) Color Match: Oscar:56/57, Alfa:44/39, Bravo:0/4, Charlie:0/0. Within the observation period (recall rate: 95%), three restorations out of 116 at baseline fractured, one restoration showed a secondary caries, one tooth received endodontic treatment, and all other restored teeth remained vital. After 2 years, no statistically significant difference (Chi-square test) in the overall survival rate between the group with the additional use of Revolution (92.8%) and that without Revolution (94.6%) was found. The combined survival rate for both groups together was 93.7% of clinically acceptable restorations.

Adult↗

PubMed2003

Reduction of polymerization shrinkage stress and marginal microleakage using soft-start polymerization.

PURPOSE: This study evaluated the influence of a soft-start light-curing exposure on polymerization shrinkage stress and marginal integrity of adhesive restorations. MATERIALS AND METHODS: Six resin-based composites (Pertac II, Tetric Ceram, Definite, Surefil, Solitaire, and Visio-Molar) were adhesively bonded to a cylindrical cavity (n = 9 per material/light) in a photoelastic material. Visible light-curing was applied using either the standard polymerization mode (800 mW/cm2 exposure duration 40 s) of the curing light (Elipar TriLight, 3M ESPE) or the exponential mode from the same device (ramp-curing: 150 mW/cm2 to 800 mW/cm2 within the first 15 s of a total curing time of 40 s). Polymerization stress was calculated at 5 minutes, 1 hour, and 24 hours postexposure from the second-order isochromatic curves obtained from photoelastic images (Matrox-Inspector). Two standardized Class V preparations were made each on the facial and lingual surfaces of 80 extracted human molars and premolars. Resin restorative systems (Pertac II/EBS Multi, Tetric Ceram/Syntac, Definite/Etch&Prime 3.0, and Surefil/Prime & Bond 2.1) were exposed using both light exposure modes (n = 20). Marginal dye penetration (2% methylene blue) was investigated separately for enamel and cementum margins after thermocycling. To obtain information on equivalent depth of cure, relative surface hardness measurements were performed on resin samples of the same material at the top surface and at 1.5 mm and 3.0 mm thickness (Zwick 3212, 10 N). RESULTS: A significant (p < .01) reduction in polymerization stress of 7.1% for Pertac II, 4.1% for Tetric Ceram, 3.6% for Definite, 3.7% for Surefil, and 6.2% for Solitaire was observed when using the exponential mode as opposed to the standard. A significant (p = .04) reduction of marginal dye penetration was found only for Pertac II/EBS Multi at the cementum margins when the soft-start polymerization was used. For the sample thickness of 3 mm, a significant higher relative bottom to top surface ratio in favor of the standard exposure mode was found (p = .001). CLINICAL SIGNIFICANCE: Depending on the restorative material, soft-start polymerization may lead to a significant reduction in marginal microleakage of adhesive Class V restorations. This effect might be attributable to a significantly lower polymerization stress, as seen from photoelastic analysis, and/or a decrease in the degree of conversion, as deducted from surface hardness ratios. However, the effect of soft-start curing mode depends on the material itself, with the most effective response from hybrid resin-based composites.

Acetone↗

PubMed2002

Clinical performance of resin composite restorations after 2 years.

The objective of this study was to evaluate the clinical performance of a packable restorative material, after 2 years in stress-bearing posterior cavities, according to the Ryge criteria. At least two Class 2 restorations (occluso-mesial, mesial-occlusal-distal, occlusal-distal) were placed in 46 patients (36.7 +/- 16 years). In each of the restorations (lot 221, metal matrix band system, glass ionomer-cement-base in 53% of the cavities, mostly no rubber dam) an adhesive system was used. Additionally, in each patient a flowable composite was used in one of the two fillings. After 2 years, 70% of the patients were available for reevaluation. Two restorations needed to be replaced as a result of postoperative sensitivities within the observation period, and one tooth received root canal treatment. All other restored teeth remained vital. One restoration with marginal discoloration received a score of Charlie; another with secondary caries received a score of Bravo. All the others revealed excellent and clinically acceptable results. No statistically significant difference (Chi-square-test) was observed between the two groups, with and without an additional flowable composite. After 2 years, the restorative material performed clinically well, with no observable fractures in the restoration.

Bicuspid↗

PubMed2002

Decrease in power output of new light-emitting diode (LED) curing devices with increasing distance to filling surface.

PURPOSE: This study compares the percentage decrease in power output of light-emitting diode (LED) and quartz-tungsten-halogen (QTH) curing devices at different distances between the light guide tip and a radiometer. MATERIALS AND METHODS: Three LED curing devices (Elipar FreeLight/3M ESPE, Luxomax/Akeda, e-Light/GC) were compared to two QTH curing devices (Elipar TriLight/3M ESPE, Optilux 501 conventional and Turbo light guides/Kerr-Demetron). Power density was measured with a Fieldmaster GS/Coherent unit (Sensor LM-3 HTD) at increasing distances from the light guide tip (0 to 20 mm at 1-mm increments, n=6). RESULTS: The mean decrease in power density available for curing at a distance of 10 mm between the light guide tip and the radiometer was 68% for the FreeLight, 83% for the e-Light, 42% for the Luxomax, 38% for the TriLight, 33% for the Optilux with the standard light guide, and 44% for the Optilux with the turbo light guide. The power density of the Luxomax was only 40% of that of the other LED curing devices at 0 mm distance. CONCLUSION: The blue LED curing devices Elipar FreeLight and GC e-Light showed a significantly higher percentage decrease in power output at a distance of 10 mm from the light guide tip to the radiometer compared to the QTH curing devices. Therefore, although blue LED curing devices might have the same curing potential compared to a QTH device when placed in direct contact to a resin composite, blue LED curing devices may not provide a sufficient cure when placed at a clinically relevant distance of 10 mm to the resin composite surface.

Composite Resins↗

PubMed2002

Marginal adaptation of self-etching adhesives in Class II cavities.

PURPOSE: An in vitro dye-penetration study was performed on 2 different self-etching adhesives (Prompt L-Pop II, 3M-Espe; NRC, Prime&Bond NT Quix, Dentsply/DeTrey) in comparison to conventional conditioning of the cavity with phosphoric acid (Conditioner 36, P&B NT Quix, Dentsply/DeTrey). MATERIALS AND METHODS: Standardized mod cavities (one cervical margin in cementum, one in enamel) were prepared in 80 extracted human teeth (n = 20/group). Prompt L-Pop II was employed in two different sequences: A: placing the matrix band first, then applying the adhesive, B: first applying the adhesive, then placing the matrix band. The adhesive was cured in both cases. Conditioning and application of P&B NT Quix was carried out after placement of the matrix band in both procedures. The compomer Dyract AP was used as a restorative material in all cavities. After thermocycling, the median percentages of dye-penetrated (2% methylene blue) margins were determined separately for the cementum and enamel margins of the approximal boxes and for the lateral enamel margins of the boxes. RESULTS: The results showed that when using Prompt L-Pop II in Class II cavities, the adhesive should be applied before placing the matrix band (p < 0.0001). When the matrix band was placed first, P&B NT Quix showed superior results at a statistically significant level (p < 0.0001) in comparison to Prompt L-Pop II. There was no significant difference in the use of P&B NT Quix in combination with NRC or phosphoric acid in these Class II cavities. CONCLUSION: It is strongly recommended that Prompt L-Pop be applied prior to placement of the matrix band. Prime & Bond NT Quix seems to provide clinically relevant marginal seal in Class II cavities, regardless of whether NRC or phosphoric acid is used for conditioning.

Acid Etching, Dental↗