Biomedical subjects

Brita Willershausen

Publications and source records attributed to Brita Willershausen.

10 recordsLinked to original sources

PubMed2003

Effects of esradiol and progesterone on the proliferation of human gingival fibroblasts.

AIM: The aim of the in vitro study was to examine the effect of estradiol and progesterone on the proliferation rate of human gingival fibroblasts (HGF) derived from a healthy and a diabetic (type II) individual. METHODS: In the first experiment, cells in the logarithmic proliferative phase were incubated with estradiol or progesterone at concentrations of 10, 50, and 100 microg/ml for 72 h. Beside the hormones, a glucose solution at a concentration of 200 mg/dl was added to the cell cultures in the second experiment in order to mimic a diabetic situation. The proliferation rate of the cells was determined by means of fluorescence activity of a redox indicator (Alamar Blue(R) Assay) added to the cell culture. Proliferation, expressed in relative fluorescence units (RFU), was determined after 24, 48, and 72 h. RESULTS: Progesterone at concentrations of 50 and 100 microg/ml significantly (Mann-Whitney-U-Test, p<0.05) reduced cellular growth in both cultures. Estradiol did not have a significant effect on cellular growth. The effect of progesterone was slightly reduced by glucose when cells from the healthy individual were used and remained almost unchanged with the cells from the diabetic patient. CONCLUSIONS: The results of the present study may help to understand the role of the female sex-hormones in the development of gingival and periodontal diseases during pregnancy. Further research work, however, is needed to elucidate the cellular mechanisms leading to the effects observed.

Cell Division↗

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↗

PubMed2003

Efficacy of subgingival irrigation using herbal extracts on gingival inflammation.

BACKGROUND: The aim of the present study was to investigate the efficacy of an herbal-based mouthrinse in combination with an oral irrigator in reducing gingival inflammation. METHODS: A total of 89 patients (45 females, 44 males; mean age 49.1 +/- 1.31 years) were included in this prospective, randomized, double-blind clinical study and allocated to 3 treatment groups: group 1 (n = 34), treated with an oral irrigator with subgingival tips and an herbal-based mouthrinse; group 2 (n = 29), the oral irrigator was applied in combination with a conventional mouthwash; and group 3 (n = 26), treated with the conventional mouthwash without subgingival irrigation. Data collected at baseline and after 4, 8, and 12 weeks included gingival index (GI), sulcus bleeding index (SBI), plaque index (PI), and probing depth (PD). RESULTS: Over a period of 3 months, GI decreased from 1.80 +/- 0.04 to 1.56 +/- 0.04 in group 1; from 1.79 +/- 0.05 to 1.68 +/- 0.04 in group 2; and remained nearly constant in group 3 (from 1.79 +/- 0.05 to 1.81 +/- 0.04). Differences between the groups were significant (analysis of variance, P < 0.05). SBI values in group 1 were reduced from 2.51 +/- 0.06 to 2.13 +/- 0.06 after 3 months and were significantly lower than in group 2 (P = 0.001) and 3 (P = 0.002), with SBIs of 2.44 +/- 0.06 and 2.42 +/- 0.07, respectively, after 12 weeks. A reduction in PI was noted for all 3 groups throughout the follow-up period, with no statistically significant differences. Probing depths were not reduced significantly in any group. CONCLUSION: Subgingival irrigation with an herbal-based mouthrinse led to a significant reduction in both SBI and GI. This regimen can, therefore, be recommended as an adjunctive procedure to reduce gingival inflammation.

Analysis of Variance↗

PubMed2002

Treatment aspects for patients with infectious diseases in dental practices--results of a survey.

AIMS: The dental treatment of patients with infectious diseases can pose certain problems and irritations not only for the dental team but also for other patients. In this study, a large number of patients were questioned to obtain a spectrum of opinions about problems associated with patients with infectious diseases in dental practices. METHODS: An especially formulated questionnaire for five selected infectious diseases (HIV infection, hepatitis A, B, and C and tuberculosis) has been distributed amongst 1,100 dental patients (statistical analysis: univariable and bivariable frequencies, contingency table, Wilcoxon text, Fisher text; error probability =<5 %). The participants were to provide statements about their knowledge of the different infectious diseases and the transmission methods as well as their personal ideas about the contact with infected patients. A further set of questions dealt with aspects of the fear of contracting an infection and with the resulting consequences such as the situation for patients in the waiting room, hygiene practices in the dental office, the course of dental treatments and the trust placed in the dentist. RESULTS: The return rate was 61.7%. 53% of the participants were female and 47% were male with the age ranging from 14 years to over 60 years. The degree of knowledge of the selected infectious diseases showed somewhat marked differences (HIV infection 96%, hepatitis A 77%, hepatitis B 83.8%, hepatitis C 68.0%, tuberculosis 91.5%). Significant correlations could be made between the knowledge about means of transmission and the level of education. 41.4% of the participants indicated a high fear of an HIV infection, followed by tuberculosis (28.0%) and hepatitis C (18.6%). 8.4% of the participants were in favor of a separate waiting room for HIV patients, the number for hepatitis ranged between 11.6% and 15.2% and was 55.1% for tuberculosis. 17.2% of the participants were afraid of contracting an infection at a dental office. The opinion that infected patients should be treated in a dental clinic was significantly higher amongst participants with a lower level of education. 46.1% of the participants believed that their dentist had enough knowledge about infectious diseases, 17.8% were of the opposite opinion. A total of 76.7% of the participants was open to a personal discussion with their dentist about subjects relevant to infectious diseases. - CONCLUSIONS: It could be noted conclusively that the statements made by the participants showed a number of uncertainties and differences, which can indicate a lack of information about infectious diseases as well as in the confidence placed in the competence of the dentists.

Adolescent↗

PubMed2002

Low level 809-nm diode laser-induced in vitro stimulation of the proliferation of human gingival fibroblasts.

BACKGROUND AND OBJECTIVE: The authors investigated the effects of low level laser irradiation on the proliferation rate of human gingival fibroblasts (HGF) in vitro. STUDY DESIGN/MATERIALS AND METHODS: HGF were obtained from gingival connective tissue explants and cultured under standard conditions. 110 cell cultures in their logarithmic growth phase were spread on 96-well tissue culture plates and were irradiated at energy fluences of 1.96-7.84 J/cm(2). Another 110 cultures served as control. An 809-nm semiconductor laser operated at a power output of 10 mW in the cw-mode was used. The time of exposure varied between 75 and 300 seconds. Laser treatment was performed alternatively once, twice, and three times at a 24-hour interval. After lasing, incubation was continued for 24 hours. The proliferation rate was determined by means of fluorescence activity of a redox indicator added to the cell culture. Proliferation was determined 24, 48, and 72 hours after irradiation and expressed in relative fluorescence units (RFU). RESULTS: The irradiated cells revealed a considerably higher proliferation activity. The differences were highly significant 24 hour after irradiation (Mann-Whitney U-test, P < 0.05) but decreased in an energy-dependent manner after 48 and 72 hour after irradiation. CONCLUSIONS: A cellular effect of the soft laser irradiation on HGF is evident. Its duration, however, seems to be limited. These findings might be clinically relevant, indicating that repeated treatments are necessary to achieve a positive laser effect in clinical applications.

Cells, Cultured↗

PubMed2002

Marginal integrity of different resin-based composites for posterior teeth: an in vitro dye-penetration study on eight resin-composite and compomer-/adhesive combinations with a particular look at the additional use of flow-composites.

OBJECTIVE: To determine improvements in marginal adaptation of resin-based composite restorative systems by means of flow-composites (Solitaire 2/Gluma Solid Bond, Solitaire 2/Flow Line/Gluma Solid Bond, Point 4/Optibond Solo Plus, Point 4/Revolution/Optibond Solo Plus) and to determine the equality of simplified bonding systems (Solitaire 2/Gluma Comfort Bond, Tetric Ceram/Tetric Flow/Excite, Dyract AP/Prime & Bond NT/NRC, Pertac II/Prompt-L-Pop) in marginal gap formation. METHODS: The marginal dye penetration (2% methylene-blue) was investigated separately for the approximal boxes of Class II mod-cavities with one cervical margin of the approximal box within enamel, the other within cementum. The surface analysis determined the percentage of dye-penetrated cervical and lateral margins of the approximal boxes, while the in depth investigation reported the mean dye penetration (mm) at both different cervical margins. RESULTS: After thermocycling (5000 x , 5-55 degrees C) the percentage of dye penetration at the cervical cementum margins ranged from 16.5 +/- 5.9% (Solitaire/Flow Line/Gluma Solid Bond) to 82.8 +/- 5.7% (Pertac II/Prompt L-Pop), for the cervical enamel margins from 10.1 +/- 5.2% (Dyract AP/NRC/P & B NT) to 72.7 +/- 7.9% (Pertac II/Prompt L-Pop), and for the lateral enamel margins of the approximal boxes from 4.8 +/- 2.3% (Dyract AP/NRC/P & B NT) to 53.9 +/- 6.8% (Pertac II/Prompt L-Pop). In the in-depth dye penetration investigation the mean dye penetration ranged from 0.2 +/- 0.2 mm (Point 4/Revolution/Optibond Solo Plus) to 1.7 +/- 0.2 mm (Pertac II/Prompt L-Pop) at the cementum margins. At the enamel margins only Pertac II/Prompt L-Pop and Solitaire 2/Gluma Solid Bond showed mean in depth dye-penetrations deeper than 0.1 mm. SIGNIFICANCE: Pertac II/Prompt-L-Pop showed a statistically significant (significance level alpha = 0.05, Wilcoxon test) higher percentage of dye-penetrated margins than most of the other restorative systems.

Compomers↗

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↗