In vitro evaluation of whitening efficacy and side effects of cosmetic bleaching agents using up to 6% hydrogen peroxide according to the EU directives 2011/84/EU compared to medical bleaching agents containing up to 40% hydrogen peroxide

Ziel Das Ziel der vorliegenden Arbeit war die Untersuchung 9 verschiedener Bleich-Produkte mit einem Wasserstoffperoxid-Gehalt (HP) von 0% bis 40% hinsichtlich ihrer aufhellenden Wirkung sowie ihrer möglichen Nebenwirkungen auf die Schmelzoberfläche und hinsichtlich ihrer Auswirkungen auf die Überlebenswahrscheinlichkeit und das Proliferationsverhalten von Zellen in Kultur. Material und Methoden Für diese Arbeit wurden 240 Rinder-Frontzähne herangezogen. Nach randomisierter Aufteilung dieser in 3 experimentelle Gruppen [erste Gruppe: „home“ Bleich-Produkte 6% HP: Opalescence® PF (OP 10CP), Philips ZOOM®! NiteWhite® (PNW 16CP), Philips ZOOM®! DayWhite® (PDW 6HP); zweite Gruppe: „in-office“ Bleich-Produkte 6% HP: Philips ZOOM®! 6% (PZ 6 HP), Magic White® (MW 0HP), Smartbleach® (SB 6HP); dritte Gruppe: „in-office“ Bleich-Produkte >6% HP: Philips ZOOM®! 25% (PZ 25 HP), Opalescence® Boost (OP 40HP), Philips Dash (PD 30HP)] und eine Kontrollgruppe (jeweils n = 24), wurden alle Zähne künstlich gefärbt und entsprechend der jeweiligen Herstellerangaben gebleicht. Die Farbmessung erfolgte mithilfe eines Spektrophotometers unter Verwendung des bleached index (BI) und WID-Index vor, unmittelbar nach, sowie 7, 14 und 21 Tage nach dem abgeschlossenen Bleichvorgang. Um die vorliegenden HP-Konzentrationen und die pH-Werte der verwendeten Bleich-Produkte zu untersuchen, wurde eine chemische Analyse durchgeführt. Zusätzlich wurden die Schmelzoberflächen zweier zufällig ausgewählter Proben jeder Gruppe mittels Rasterelektronenmikroskopie (REM) analysiert und alle verwendeten Bleich-Produkte wurden in Zellkulturversuchen hinsichtlich ihrer Auswirkungen auf die Überlebenswahrscheinlichkeit (mittels MTT Assay) und das Proliferationsverhalten (mittels BrdU Assay) der L929 Mäuse-Fibroblasten nach 2-minütiger Stimulation mit unterschiedlichen Konzentrationen untersucht. Ergebnisse Alle Produkte aus der Gruppe der „home“ Bleich-Produkte mit einem HP-Gehalt von 6%, ein Produkt (PZ 6HP) aus der Gruppe der „in-office“ Bleich-Produkte mit einem HP-Gehalt von 6% sowie alle Produkte aus der Gruppe der „in-office“ Bleich-Produkte mit einem HP-Gehalt von >6% erzielten einen statistisch signifikanten aufhellenden Effekt nach dem Bleichvorgang. Bei der chemischen Analyse aller getesteten Bleich-Produkte zeigten vier Produkte höhere HP-Konzentrationen. Drei Produkte wiesen bei der chemischen Analyse niedrigere pH-Werte auf als in der Herstellerbeschreibung angegeben. Die deskriptive Interpretation der REM-Bilder zeigten bei niedrigen pH-Werten, kurzer Einwirkzeit und niedrigen HP-Konzentrationen der Bleich-Produkte geringere strukturelle Veränderungen der Schmelzoberfläche als bei den Vergleichsprodukten. Alle getesteten Bleich-Produkte zeigten in der Zellkultur negative Auswirkungen auf die Überlebenswahrscheinlichkeit und das Proliferationsverhalten der Mäuse-Fibroblasten, wobei jedoch in unterschiedlichem Ausmaß und mit variierenden Werten der halbtoxischen Konzentration. Schlussfolgerungen Die Ergebnisse dieser Arbeit weisen darauf hin, dass niedrige Wasserstoffperoxid-Konzentrationen und niedrige und neutrale pH-Werte in Bleich-Produkten in Kombination mit einer kurzen Einwirkzeit ein deutlich aufhellendes und sicheres Profil haben und daher für das Bleichen von Zähnen empfohlen werden können.Aim The objective of the present thesis was the evaluation of 9 different bleaching agents, containing hydrogen peroxide (HP) from 0% up to 40%, regarding their whitening efficacy and their possible side effects on enamel surfaces. Furthermore, their effects on the viability and proliferation behavior of cells in culture were investigated. Materials and Methods 240 bovine anterior teeth were used for this thesis. After random allocation into 3 experimental groups [first group: home bleaching products 6% HP: Opalescence® PF (OP 10CP), Philips ZOOM®! NiteWhite® (PNW 16CP), Philips ZOOM®! DayWhite® (PDW 6HP); second group: in-office bleaching products 6% HP: Philips ZOOM®! 6% (PZ 6HP), Magic White® (MW 0HP), Smartbleach® (SB 6HP); third group: in-office bleaching products >6% HP: Philips ZOOM®! 25% (PZ 25HP), Opalescence® Boost (OP 40HP), Philips Dash (PD 30HP)] and one control group (n=24, each), all teeth were artificially stained and bleached following the instructions of the respective manufacturer. Color measurement was performed using a spectrophotometer utilizing the bleached index (BI) and the whiteness index (WID) before bleaching procedure, at baseline as well as 7, 14, and 21 days after bleaching, respectively. In order to evaluate the present HP concentrations and the pH values of the used bleaching products, chemical analysis was conducted. In addition, the enamel surfaces of two randomly selected specimens of each group were analyzed using scanning electron microscopy (SEM) and all used bleaching materials were examined regarding their influence on the viability (MTT assay) and proliferation (BrdU assay) of L929 mouse fibroblasts after stimulation for two minutes with different concentrations of the bleaching products. Results All products of the group of home bleaching products containing 6% HP, one product (PZ 6HP) of the group of in-office bleaching products containing 6% HP, and all products of the group of in-office bleaching products containing >6% HP resulted in statistically significant bleaching effects after the bleaching procedure. Regarding the chemical evaluation of all tested bleaching agents, four products showed higher HP concentrations. Moreover, three products presented lower pH values than described in the manufacturers description. Descriptively interpreting the SEM images, low pH values, short time of contact, and low HP concentration of the bleaching products lead to rather lower enamel surface alterations. All tested bleaching products showed reduced cell viability and an increase in proliferation, but with different extend and varying LC50 data. Conclusions The results of this thesis demonstrate low hydrogen peroxide and low to neutral pH values of bleaching products in combination with short exposure time to have an effective and safe profile. Therefore, they are recommended for clinical use.Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersArbeit an der Bibliothek noch nicht eingelangt - Daten nicht geprüftMedizinische Universität Wien, Diss., 2018(VLID)365287

Evaluation of the Morphological Characteristics of Laser-Irradiated Dentin

OBJECTIVE The aim of this study was to investigate the effect of different energy settings of Er:YAG laser irradiation on dentin surface morphology with respect to the number of opened dentinal tubules. BACKGROUND DATA An ideally prepared dentin surface with opened dentinal tubules is a prerequisite for adhesive fixation. No study, however, has yet compared the numbers of opened dentinal tubules with regard to statistical differences. METHODS Conventional preparations using a bur with or without additional acid etching acted as control groups. Dentin specimens were prepared from human third molars and randomly divided into eight groups according to the energy settings of the laser (1, 1.5, 4, 6, 7.5, and 8 W) and two controls (bur and bur plus acid etching). After surface preparation, dentin surfaces were analyzed with a scanning electron microscope, and the number of opened dentinal tubules in a defined area was counted. RESULTS The control groups showed smooth surfaces with (bur plus acid etching) and without opened dentinal tubules (bur), whereas all laser-irradiated surfaces showed rough surfaces. Using the energy setting of 4 W resulted in significantly more opened dentinal tubules than the conventional preparation technique using the bur with additional acid etching. In contrast, the energy setting of 8 W showed significantly fewer opened dentinal tubules, and also exhibited signs of thermal damage. CONCLUSIONS The Er:YAG laser with an energy setting of 4 W generates a dentin surface with opened dentinal tubules, a prerequisite for adhesive fixation

Effect of two different primers on the shear bond strength of metallic brackets to zirconia ceramic

Abstract Background In view of the increasing demand of adult orthodontics for esthetic purposes, adult treatment with brackets has become an important issue. One essential factor for the quality of such treatment is bracket bonding on ceramics. For testing the adhesive bond between the bracket and the ceramic surface it is important to consider the static or cyclic loading that goes along with it. Methods Metallic Brackets were adhesively fixed on zirconia ceramic blocks in a simulated leveling phase using two different primers (Monobond S and Monobond Etch & Prime). Half of the metallic brackets were activated using a 0.14-nickel titanium wire, while the other half remained non-activated. Shear bond testing (SBT) was performed after thermocycling. Furthermore the Adhesive Remnant Index (ARI) was analyzed. Results SBT resulted in significantly higher shear bond values when Monobond Etch & Prime was used compared to the use of Monobond S. Activation of the brackets did not show different results in comparison to the non-activated brackets. The ARI did not indicate cement remnants on the ceramic surface, regardless of the primer and the activation status. Conclusions The use of Monobond Etch & Prime has great potential for the bonding of brackets on dental zirconia ceramics

Comparison of marginal fit of cemented zirconia copings manufactured after digital impression with lava™ C.O.S and conventional impression technique.

BACKGROUND Evaluation of the marginal fit of cemented zirconia copings manufactured after digital impression with Lava™ Chairside Oral Scanner in comparison to that of zirconia copings manufactured after conventional impressions with polyvinyl siloxane. METHODS A prepared typodont tooth #36, was replicated 40 times with a vinyl silicone and precise model resin. The dies were randomly divided into two groups according to the impression taking technique. Digital impressions with Lava™ C.O.S. and conventional impressions were taken according to the group. Subsequently zirconia copings were manufactured and cemented on their respective dies with zinc oxide phosphate cement. After embedding in resin, mesio-distal section of each coping was performed with a diamond saw in order to obtain two slices. One half of the specimen was used for evaluation with an optical microscope (OM) and the other half for evaluation with a scanning electron microscope (SEM). Marginal gap (MG) and absolute marginal discrepancy (AMD) were measured mesial and distal on each slice. RESULTS No significant difference of the marginal parameters between the digital and the conventional group was found. The mean values for MG in the digital group were 96.28 μm (+/-43.21 μm) measured with the OM and 99.26 μm (+/-48.73 μm) measured with the SEM, respectively. AMD mean values were 191.54 μm (+/-85.42 μm) measured with the optical microscope and 211.6 μm (+/-96.55 μm) with the SEM. For the conventional group the mean MG values were 94.84 μm (+/-50.77 μm) measured with the OM and 83.37 μm (+/-44.38 μm) measured with the SEM, respectively. AMD mean values were 158.60 μm (+/-69.14 μm) for the OM and 152.72 μm (+/-72.36) for the SEM. CONCLUSIONS Copings manufactured after digital impression with Lava™ C.O.S. show comparable marginal parameters with the copings manufactured after conventional impression with polyvinyl syloxane. The mean MG values of both groups fit in the clinically acceptable range

Frontiers in Physiology / Comparison of Bleaching Products With Up to 6% and With More Than 6% Hydrogen Peroxide: Whitening Efficacy Using BI and WID and Side Effects An in vitro Study

The aim of this study was to evaluate the effect of bleaching agents containing different concentrations of hydrogen peroxide (HP) on color-change and on enamel-surface in bovine teeth. Furthermore the influence on cell viability and proliferation was investigated. Two hundred and forty teeth were randomly assigned into four groups (home bleaching 6%, in-office bleaching 6%, in-office bleaching > 6% HP, and control group). Bleaching was performed after artificial staining and the bleached index (BI) as well as the whiteness index (WID) was measured at several time points. Chemical analysis for HP concentrations and the pH of the bleaching products was done. Furthermore, enamel surfaces of randomly selected specimens were analyzed using scanning electron microscopy (SEM) and cytotoxicity of the tested bleaching products was evaluated in vitro using dental pulp cells (DPCs) and L929 cells. A statistically significant whitening effect was observed in almost all products. As expected all investigated products resulted in decreased cell viability, however, with different values of LC50 (median lethal concentration). SEM analysis showed an analog of enamel alterations with decreasing pH, increasing exposure time, and increasing HP concentration. Bleaching agents containing a low HP concentration are considered to be effective and to have less damaging effects on enamel and tested cells.(VLID)490832

Additional file 1: of Comparison of marginal fit of cemented zirconia copings manufactured after digital impression with lava™ C.O.S and conventional impression technique

Dauti et al._raw data. Description of data: Results showing MG and AMD in mesial and distal position for the digital and conventional group measured with the SEM and the optical microscope. Furthermore the results after additional experiments using the silicone replica technique are shown. (PDF 31 kb

The 6th Albanian Congress of Trauma and Emergency Surgery

After a three-year quarantine from the deadliest global pandemic of the last century, ASTES is organizing to gather all health professionals in Tirana, The 6th Albanian Congress of Trauma and Emergency Surgery(ACTES 2022) on 11-12 November 2022, with the topic Trauma & Emergency Surgery and not only...with the aim of providing high quality, the best standards, and the best results, for our patients ...ACTES 2022 is the largest event that ASTES (Albanian Society for Trauma and Emergency Surgery) has organized so far with 230 presentations, and 67 foreign lecturers with enviable geography, making it the largest national and wider scientific event.The scientific program is as strong as ever, thanks to the inclusiveness, where all the participants with a mix of foreign and local lecturers, select the best of the moment in medical science, innovation, and observation.The scientific committee has selected all the presentations so that the participants of each medical discipline will have something to learn, discuss, debate, and agree with updated methods, techniques, and protocols.I hope you will join us on Friday morning, and continue the journey of our two-day event together