Biomedical subjects

Aikaterini Papathanasiou

Publications and source records attributed to Aikaterini Papathanasiou.

6 recordsLinked to original sources

PubMed2006

Clinical evaluation of chemical and light-activated tooth whitening systems.

Tooth whitening has become one of the most popular dental treatments available. This article compares the efficacy of 2 in-office whitening systems using a split-arch, randomized, parallel, blinded clinical evaluation study. Both in-office tooth whitening systems were effective and there was no significant statistical difference over the 2-week period of observation. The use of light did not demonstrate any benefit over the chemically activated tooth whitening system after a 2-week recall.

Double-Blind Method↗

PubMed2004

Clinical evaluation of a combined in-office and take-home bleaching system.

BACKGROUND: Tooth whitening is one of the fastest growing areas in cosmetic and restorative dentistry. An increasing number of patients are demanding faster ways to bleach their teeth. Therefore, clinicians are being pushed to seek quicker and easier means to bleach their patients' teeth, while maintaining safety in bleaching procedures. METHODS: The authors included in the clinical trial 10 subjects 18 years of age or older, each of whom had six caries-free maxillary anterior teeth without restorations on the labial surfaces and no tooth sensitivity. For each subject, one-half of the maxillary arch received a 35 percent hydrogen peroxide (Group 1) gel application for 30 minutes, and the other one-half of the maxillary arch received a 38 percent hydrogen peroxide (Group 2) gel application for 30 minutes. The in-office bleaching treatment was maintained and reinforced using a 10 percent carbamide peroxide at-home bleaching agent for 60 minutes. Subjects repeated both the in-office and take-home bleaching treatments for three consecutive days. RESULTS: The shade change was 8.5 for Group 1 and 9 for Group 2. There was no statistically significant difference between the two groups (P = .3434). An average shade rebound of two shades was recorded at seven days for both treatment systems. No sensitivity was reported during or after the bleaching treatment. CONCLUSIONS: When combined with 10 percent carbamide peroxide at-home applications, use of the Group 1 and Group 2 bleaching materials resulted in significant tooth lightening. CLINICAL IMPLICATIONS: By using the clinical technique presented, clinicians can reduce the time required to complete tooth-whitening treatment. Using the correct tray design and improved chemical formulations of tooth whiteners may reduce gingival and tooth sensitivity, thus increasing safety.

Adolescent↗

PubMed2004

Microleakage of a microhybrid composite resin using three different adhesive placement techniques.

PURPOSE: To evaluate the efficacy of two adhesive systems in reducing microleakage when applied with three different adhesive placement techniques. MATERIALS AND METHODS: Sixty freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into 2 groups (group I: Prime& Bond NT, Dentsply/Caulk; group II: Single Bond, 3M Espe). Each group was divided into 3 subgroups: (A) application of 2 coats and one cure: IA-IIA; (B) 2 coats and 2 cures of each adhesive system: IB-IIB; and (C) one coat of each adhesive along with the manufacturers' B1 flowable resin (0.5-mm thick layer) cured together at once: IC-IIC. Each coat was cured for 20 s at 800 mW/cm2 using a quartz-tungsten halogen light (Elipar Trilight, 3M ESPE). Teeth were then restored using 2-mm increments of an A2 microhybrid composite (Esthet-X, Dentsply/Caulk). All teeth were stored in distilled water at 37 degrees C for 24 h, thermocycled (500x, 5 degrees to 55 degrees C, 30 s dwell) and then placed in a 0.5% methylene blue dye solution for 24 h at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at 20x magnification. Dye penetration was scored using an ordinal scoring system, where 0: no penetration; 1: enamel penetration; 2: gingival dentin penetration; 3: axial dentin penetration. Kruskal-Wallis and Mann-Whitney tests were used. RESULTS: A Mann-Whitney U-Test revealed no statistically significant difference between subgroups. Although not statistically significant, P&B NT (two coats and one cure) revealed the lowest microleakage scores. CONCLUSION: In the experimental model adopted for this study, microleakage was not affected either by the adhesive or its placement technique.

Bisphenol A-Glycidyl Methacrylate↗

PubMed2003

Effect of different polymerization methods on composite microleakage.

PURPOSE: To evaluate the microleakage of a condensable resin composite using a microhybrid flowable composite as a liner, cured with four different methods of polymerization. METHODS: 40 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into four groups. Group 1 (control group): conventional mode (Elipar Highlight), Group 2: step mode (Elipar Highlight), Group 3: ramp mode (Elipar Trilight) and Group 4: pulse mode (VIP). Preparations were etched with 32% phosphoric acid (Uni-Etch) and an adhesive system (One-Step) was used according to the manufacturer's instructions. Teeth were then restored using a 1 mm layer of flowable composite (A2 AEliteflo LV) on the gingival and pulpal floor and condensable composite (Pyramid A2 Dentin and A1 Enamel) in 2 mm increments. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x30 magnification. Dye penetration was scored using an ordinal scoring system as 0: no penetration; 1: enamel penetration; 2: dentin penetration. RESULTS: A Mann-Whitney U Test revealed a statistically significant difference between Group 1 with Groups 2, 3 and 4 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between Groups 2, 3 and 4.

Acid Etching, Dental↗

PubMed2003

Microleakage of resin-based liner materials and condensable composites using filled and unfilled adhesives.

PURPOSE: To evaluate the efficacy of differing resin based liner materials in reducing microleakage. METHODS: 80 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into two groups; each one was divided into four subgroups (A-B-C-D for Group 1 and E-F-G-H for Group 2). Each prepared tooth was etched with 32% H3PO4 (Uni Etch); in Group 1, one coat of One Step and in Group 2, two coats and two cures of Prime & Bond NT adhesives were applied. In each group 1 mm layer of three different liners was used: A2 Heliomolar RO for A and E; A2 Heliomolar Flow for B and F; A2 Bisfil 2B for C and G. No liner was used for D and H subgroups. Teeth were then restored using 2 mm increments of Pyramid A2 Dentin and A1 Enamel and cured with a VIP curing light. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x20 magnification. Dye penetration was scored using an Ordinal Scoring System where 0= no penetration; 1= enamel penetration; and 2= dentin penetration. RESULTS: A Chi Square Test revealed a statistically significant difference between Group 1 and Groups 2 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between the subgroups of each group; a statistically significant difference of B and D vs. E and H (P < 0.01 > 0.001) and B vs. G and D (P < 0.05 > 0.01) was also noted. The dentin bonding agent in Group 2 contributed to a reduction of microleakage when compared to Group 1.

Acid Etching, Dental↗

PubMed2002

Clinical evaluation of a 35% hydrogen peroxide in-office whitening system.

This study evaluated the effectiveness of light-curing (heat conversion) vs no light-curing (no heat conversion) of a 35% hydrogen peroxide in-office tooth whitening system. Twenty patients with sound medical history (without tooth sensitivity) participated in this randomized, parallel clinical evaluation. Only six maxillary anterior teeth with discoloration and a tooth shade of A3 or darker were selected. Patients received a complete prophylaxis and were evaluated for initial (baseline) shade by three independent evaluators, precalibrated at 85% rater reliability in determining shades before the experiment began. Participants received a 20-minute chairside whitening treatment with a 35% hydrogen peroxide agent using a reflective resin barrier for gingival isolation. During the whitening treatment, the 35% hydrogen peroxide agent was light-activated with a halogen curing light on teeth Nos. 6 through 8 (Group I), but was not light-activated on teeth Nos. 9 through 11 (Group II). All patients returned 24 hours after the whitening application for shade evaluation. Although there were isolated instances (7 out of 20 patients) of greater degrees of lightening in the light-curing group, there was no statistically significant difference using the Mann-Whitney U test (P > .05). This study indicates that light-curing is optional with this 35% tooth whitening system.

Cuspid↗