Diese Studie wurde von den Minnesota Dental Research-Zentrum für Biomaterialien und Biomechanik (MDRCBB) unterstützt.

Hinweis: Drei Dental Komposite wurden mit den Glas Hohlräume untersucht: Z100, Z250 und LS, wie in der Materialliste aufgeführt. Unter diesen ist bekannt, dass ein LS schrumpfarmen Harzverbundstoff mit einem Volumenschrumpfung von etwa 1,0%, viel niedriger als die der Z250 und Z100 (~ 2% und ~ 2,5%, beziehungsweise) 18-19 sein. Die Ausrüstung und die anderen in dieser Studie verwendeten Materialien werden auch in der Materialliste. 1. Modell Kavitätenpräparation <ol><li> Schneiden Sie einen langen zylindrischen Glasstab, 10 mm im Durchmesser, in 10-mm lang kurze Stäbchen mit einem Low-Speed-Diamant-Säge. </li><li> Schnitt eine mesial-distale okklusal-(MOD) Hohlraum (1) Messen 3 mm (Breite) x 2 mm (Tiefe) in jeder Probe unter Verwendung eines angepassten Niedergeschwindigkeits-Diamantsäge. </li><li> Polieren entlang jeder zylindrische Probe, um eine flache Oberfläche senkrecht zu der Länge des Hohlraums zu erzeugen, mit den Abmessungen wie in Abbildung 1 dargestellt. Die flache Oberfläche ermöglicht eine präzise focusing und Bildkalibrierung auf die Wiederherstellung. Fortan wird die Beobachtungsfläche bezeichnet werden. </li><li> Vorbereitung drei Proben für jedes der drei getesteten Materialien: Z100, Z250 und LS; siehe Materialien Tisch. </li></ol> 2. Hohlraumfüllung mit Composite-Harz <ol><li> Tragen Sie eine dünne Schicht aus Keramik Primer mit einem Pinsel auf alle Glasflächen silanisieren Hohlraum. Dies ermöglicht die Bindung zwischen den Glasflächen und den Harzverbundstoffe. </li><li> Nach ca. 1 min, eine dünne Schicht Klebstoff. Verwenden LS Klebesystem für Verbund LS und Adper Einzel Bond Plus Z100 und Z250 Verbund. </li><li> Cure den Klebstoff mit einem Lichtgerät und Dauer (10-20 Sek.), basierend auf den Angaben des Herstellers (Material Tabelle). </li><li> Decken alle Glasflächen rund um die Wiederherstellung mit schwarzem Klebeband mit Ausnahme der Beobachtungsfläche, wie in Abbildung 2 dargestellt. Ziel ist es, zu vermeiden, die Aushärtung Licht, das dieHarz-Verbund durch die umliegende transparentem Glas, die nicht im echten Zähnen geschieht. </li><li> Groß füllen den Hohlraum mit Harz-Verbund und kratzen Sie das überschüssige, alle Oberflächen zu glätten. </li></ol> 3. Oberflächen Malerei <ol><li> Sprühen Sie eine dünne Schicht der weißen Farbe auf die Beobachtungsfläche, die nun auch Teil der Harzverbund. </li><li> Streuen Sie sofort eine schwarze feine Holzkohlepulver auf die Farbe, um kontrastreiche Flecken erstellen. Die unregelmäßigen Formen der Flecken hilft, die DIC-Software, um sie identifizieren und verfolgen ihre Bewegungen. </li></ol> 4. Beispiel Montage, Aushärtung und Fotografieren <ol><li> Bezugnehmend auf 2, legen Sie ein Exemplar (E) in die Halterung (C) und ziehen Sie sie mit einer Schraube (D). Legen Sie dann die gesamte Einheit am Ende eines großen horizontalen Balken. </li><li> Sichern Sie sich eine CCD-Kamera und eine gelbe LED-Beleuchtung Licht auf die gleichen Strahlen, dass sie das Gesicht observation Oberfläche. </li><li> Mit einem Stand mit einstellbare Klemmen, positionieren Sie den Härtelampe, so dass seine Spitze ist etwa 1 mm über der Probe. </li><li> Nehmen Sie ein Bild der Probe auf das Referenzbild vor dem Aushärten werden. </li><li> Heilung der Harzverbund für 20 Sekunden. </li><li> Nehmen Sie ein weiteres Bild auf 5 min nach der Aushärtung. </li><li> Legen Sie eine Kalibrierung Block an der gleichen Position wie die Beobachtungsfläche und ein Bild. Die Kalibrierungsblock enthält eine Anordnung von kreisförmigen Punkten mit der Größe und der Abstand genau bekannt. </li></ol> 5. Bildanalyse mit DIC Software <ol><li> Importieren der beiden Bilder für jede Probe, eine vor und eine nach dem Aushärten in den DIC-Software aufgenommen. </li><li> Kalibrieren der Abmessungen der Bilder und zur Korrektur von Bildverzerrungen unter Verwendung des Bildes des Kalibrierungsblocks. . </li><li> Definieren des interessierenden Bereichs innerhalb der Betrachtungsfläche für die Analyse. </li><li> Legen Sie die Größe der quadratischen Teilfenster als 64 x 64 Pixel für dieerste Iteration und 32 x 32 Pixel für die zweite Iteration 20. Definieren Sie die Überlappung als 50%. </li><li> Korrelieren die nach dem Aushärten mit dem Referenzbild vor der Aushärtung, um die Verlagerung und Dehnungsverteilungen berechnen taken Bild. </li></ol>

<ol>
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Die Autoren erklären, dass sie keine finanziellen Interessen konkurrieren.

Die Verwendung von Glas Hohlräume mit der gleichen Form und Abmessungen für Schwindmaß Messung war die Streuung der Ergebnisse aufgrund von Unterschieden in Größe, Anatomie und Materialeigenschaften der natürlichen menschlichen Zähnen zu minimieren. Darüber hinaus ist die Quarzglas in dieser Studie verwendet wird, eine ähnliche Elastizitätsmodul an Schmelz, wodurch es ein geeignetes Material für simulant natürlichen Zähne so weit wie mechanische Verhalten angeht 21-22. Obwohl in Echt Zahnersatz w...

Harz-Verbundwerkstoffe sind weit verbreitet in restaurativen Zahnheilkunde wegen ihrer überragenden Ästhetik und Handling Eigenschaften verwendet. , Obwohl sie zu den Zahngewebe gebunden ist, die Polymerisation Schrumpfung von Kompositen bleibt jedoch eine klinische Sorge, wie die Schrumpfspannung entwickelt, kann dazu führen, Ablösen an der Zahnsanierung Schnittstelle 1 -2. Folglich können Bakterien eindringen und liegen in den Bereichen gescheitert und führen zu Sekundärkaries. Auf der anderen Seite, wenn die Wiederherstellung ist dem Zahn verbunden ist, kann der Schrumpfspannung zu Rissen im Zahngewebe. Eine dieser Defekt die Lebensdauer der Zahnrestauration, die auf eine große Anzahl von Zyklen der thermischen und mechanischen Belastung unterworfen werden gefährden. Messung der Polymerisationsschrumpfung Belastung und Stress ist damit unverzichtbar für die Entwicklung und Bewertung von Dentalharz-Verbund 3-4 </sup&gt;. Verschiedene Messverfahren oder Verfahren mit dem Hauptzweck, eine einfache Einrichtung zum Messen der Schrumpfungsverhalten von Harz-Verbundmaterialien zuverlässig entwickelt 5-11. Während die Messungen bieten sie ausreichend für den Vergleich der Schrumpfverhalten der verschiedenen Materialien sein, sie nicht für das Verständnis, wie und wo Schrumpfspannung entwickelt sich tatsächlich wiederhergestellt Zähne helfen. Insbesondere ist eine Frage von großem Interesse, wie die Hohlraumwände begrenzen die Schrumpfung des Verbundwerkstoffe und führt zur Entstehung von Schrumpfspannung in Zahnersatz 12. Beachten Sie, dass, um Schrumpfspannung, ein Teil der Schrumpfspannung der Harzverbundstoff zu schaffen, hat sich in Streck Stamm umgewandelt werden. Es wäre daher nützlich sein, wenn diese Komponente der Spannung in der Wiederherstellung gemessen werden kann. Vor kurzem hat die optische Vollfeld-Dehnungsmesstechnik, Digitale Bildkorrelation (DIC), wurde für die Messung von freiem shrinka angewendetge von Kompositen sowie Materialfluss in Zahnersatz 13-15. Die Grundidee der DIC ist, auf der Probenoberfläche von aufeinanderfolgenden Bildern während der Verformung aufgenommen, wobei die Verschiebung und Belastung Bereichen über der Oberfläche bestimmt werden kann verfolgen und sichtbare Muster korrelieren. Vollfeld-Messung ist einer der Hauptvorteile des DIC-Methode, die besonders nützlich bei der Beobachtung ungleichmäßigen Verformung und Belastung Muster 13 ist. In dieser Studie DIC wurde verwendet, um die Stamm-Muster in der Zahn Kompositrestaurationen zu entdecken, mit dem Ziel, das Verständnis der Entwicklung der Schrumpfspannung und potenzielle Standorte für Ablösung. Diese Information ist nicht in den Werken über 14-15 zitiert, die nur gemessen, die Verschiebung der Wiederherstellung durch Polymerisationsschrumpfung direkt zur Verfügung. Die Messung wurde mit Hilfe von Modellen, die mit mesial-okklusal-distalen (MOD) Karies als ein Versuch, Replik simuliert Zähne durchgeführtte die Spannung oder Dehnung in Echt Zahnersatz. Obwohl die Verwendung von echten Zähnen ist anatomisch Vertreter, der Nachteil, dass es die wesentlichen inhärenten Unterschiede zwischen den Zähnen in der Anatomie, der mechanischen Eigenschaften, dem Grad der Hydratation sowie unsichtbare innere Defekte 14, die in großen Schwankungen in den Ergebnissen führen. Um diesen Nachteil zu überwinden, haben einige Studien versucht, Zahnmuster, indem diese in Bezug auf die Mundgröße 16 oder ersetzt die Zähne zusammen mit Modellen eines Ersatzmaterial 17 standardisieren. Zum Beispiel haben Aluminium-Modelle, die eine ähnliche Elastizitätsmodul an Schmelz (69 und 83 GPa) haben in Schrumpfspannung Messung verwendet worden ist, mit der Höhe der Schrumpfspannung, die von der Spitze Umlenkung 17 angegeben. In dieser Studie wurden Quarzglas-Modelle (Hohlräume) stattdessen verwendet, weil das Material hat auch eine ähnliche Elastizitätsmodul (63 GPa) für die menschliche Zahnschmelz und, da es transparent istent, kann jeder Ablösung oder Rissbildung in den Proben leicht beobachtet werden.

<table><tbody><tr><td>Dental composite Z100</td><td>3M ESPE</td><td>N362979</td><td>volume shrinkage ~ 2.5%, Young&#039;s modulus ~ 14 GPa</td></tr><tr><td>Dental composite Z250</td><td>3M ESPE</td><td>N326080</td><td>volume shrinkage ~ 2.0%, Young&#039;s modulus ~ 11 GPa</td></tr><tr><td>Dental composite LS</td><td>3M ESPE</td><td>N240313</td><td>volume shrinkage ~ 1%, Young&#039;s modulus ~ 10 GPa</td></tr><tr><td>Ceramic Primer</td><td>3M ESPE</td><td>N167818</td><td>Rely X</td></tr><tr><td>LS System Adhesive</td><td>3M ESPE</td><td>N391675</td><td>Adhesive for compoiste LS</td></tr><tr><td>Adper Single Bond Plus</td><td>3M ESPE</td><td>501757</td><td>Adhesive for compoiste Z100 and Z250</td></tr><tr><td>Glass rod&amp;nbsp;</td><td>Corning Inc.</td><td>Pyrex 7740 borosilicate</td><td></td></tr><tr><td>Curing light&amp;nbsp;</td><td>3M ESPE</td><td>Elipar S10</td><td></td></tr><tr><td>White paint&amp;nbsp;</td><td>Krylon Product Group</td><td></td><td>Indoor/Outdoor, Flat white</td></tr><tr><td>Charcoal powder&amp;nbsp;</td><td>Sigma Aldrich, Co.</td><td>BCBH6518V</td><td>Fluka activated charcoal</td></tr><tr><td>CCD camera&amp;nbsp;</td><td>Point Grey Research, Inc.</td><td>Point Grey Gras-20S4C-C</td><td></td></tr></tbody></table>

shrinkage of dental composite in simulated cavity measured with digital image correlation

Polymerisationsschrumpfung von dentalen Kompositen kann zur Wiederherstellung Ablösung oder gerissene Zahngewebe in Verbund restaurierten Zähne führen. Um zu verstehen, wo und wie Schrumpfung Belastung und Stress entwickeln in solchen Zähnen wiederhergestellt wurde Digitale Bildkorrelation (DIC) verwendet, um einen umfassenden Überblick über die Verlagerung und Dehnungsverteilungen im Modell Restaurationen, die Polymerisationsschrumpfung unterzogen hatten, zu liefern. Proben mit Modell Hohlräume wurden von zylindrischen Glasstäbe mit einem Durchmesser und einer Länge von 10 mm gefertigt. Die Abmessungen der mesial-distalen okklusal-(MOD) Hohlraum in jeder Probe hergestellt wurde, gemessen 3 mm und 2 mm in der Breite und Tiefe sind. Nach dem Füllen der Kavität mit Harz-Komposit wurde die Oberfläche unter Beobachtung zunächst mit einem dünnen Schicht weißer Farbe und feinen schwarzen Holzkohlepulver mit hohem Kontrast erstellen Flecken gesprüht. Bilder von dieser Oberfläche wurden dann vor dem Aushärten und 5 min nach übernommen. FiNally wurden die beiden Bilder mit DIC-Software, um die Verlagerung und Dehnungsverteilungen berechnen korreliert. Harzverbundstoff geschrumpft senkrecht zum Boden des Hohlraums, wobei der obere Mittelabschnitt der Wiederherstellung mit der größten Abwärtsverschiebung. Gleichzeitig horizontal geschrumpft es in Richtung seiner vertikalen Mittellinie. Schrumpfung des gestreckten Verbund das Material in der Nähe der &quot;Zahn-Restaurierung&quot;-Schnittstelle, was Höckerbiegungen und hohen Zugspannungen rund um die Wiederherstellung. Material in der Nähe der Hohlwände oder Boden hatten direkten Stämme vor allem in den Richtungen senkrecht zu den Schnittstellen. Summierung der beiden Gleichdehnungskomponenten zeigte eine relativ gleichmäßige Verteilung um die Wiederherstellung und ihre Größe betrug etwa der Volumenschrumpfung Belastung des Materials.

Drei Proben wurden für jedes Material getestet. Nach jedem Test wurde die Probe mit dem Auge untersucht und, falls notwendig, unter Verwendung eines Mikroskops. Keine offensichtliche Ablösung bei der &quot;Zahn-Wiederherstellung&quot;-Schnittstelle oder Rissbildung festgestellt wurde. Die Auflösung der Bilder war 1600 x 1180 Pixel bei einer Pixelgröße von 5,8 mm. Mit einer Teilmenge Fenstergröße von 32 Pixeln, die räumliche Auflösung der Versetzungsverteilungen war um 186 mm. <p...

Watch this Scientific Journal Video about Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation at JoVE.com

Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation

Um die räumliche Entwicklung der Polymerisation Schrumpfspannung in der Zahn Harz-Komposit-Restaurationen zu verstehen, wurde Bildkorrelation zur Vollfeld-Verschiebung / Dehnungsmessung von restaurierten Modell Glas Hohlräume durch Korrelation Bilder der Restauration vor und nach der Polymerisation genommen werden.

Schwindung von Dental-Komposits in Simulierte Cavity mit digitalen Bildkorrelation Mess

Polymerization shrinkage of dental resin composites can lead to restoration debonding or cracked tooth tissues in composite-restored teeth. In order to ...

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JoVE Journal

Medicine

13.4K Aufrufe.  University of Minnesota.  Um die räumliche Entwicklung der Polymerisation Schrumpfspannung in der Zahn Harz-Komposit-Restaurationen zu verstehen, wurde Bildkorrelation zur Vollfeld-Verschiebung / Dehnungsmessung von restaurierten Modell Glas Hohlräume durch Korrelation Bilder der Restauration vor und nach der Polymerisation genommen werden. 

Serie: Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation

In situ Compressive Loading and Correlative Noninvasive Imaging of the Bone-periodontal Ligament-tooth Fibrous Joint

This study demonstrates a novel biomechanics testing protocol. The advantage of this protocol includes the use of an in situ loading device coupled to a high resolution X-ray microscope, thus enabling visualization of internal structural elements under simulated physiological loads and wet conditions. Experimental specimens will include intact bone-periodontal ligament (PDL)-tooth fibrous joints. Results will illustrate three important features of the protocol as they can be applied to organ level biomechanics: 1) reactionary force vs. displacement: tooth displacement within the alveolar socket and its reactionary response to loading, 2) three-dimensional (3D) spatial configuration and morphometrics: geometric relationship of the tooth with the alveolar socket, and 3) changes in readouts 1 and 2 due to a change in loading axis, i.e. from concentric to eccentric loads. Efficacy of the proposed protocol will be evaluated by coupling mechanical testing readouts to 3D morphometrics and overall biomechanics of the joint. In addition, this technique will emphasize on the need to equilibrate experimental conditions, specifically reactionary loads prior to acquiring tomograms of fibrous joints. It should be noted that the proposed protocol is limited to testing specimens under ex vivo conditions, and that use of contrast agents to visualize soft tissue mechanical response could lead to erroneous conclusions about tissue and organ-level biomechanics.

In situ Compressive Loading and Correlative Noninvasive Imaging of the Bone-periodontal Ligament-tooth Fibrous Joint

In this study, the use of an in situ loading device coupled with micro-X-ray computed tomography for fibrous joint biomechanics will be discussed. Experimental readouts identifiable with an overall change in joint biomechanics will include: 1) reactionary force vs. displacement, i.e. tooth displacement within the alveolar socket and its reactionary response to loading, 2) three-dimensional (3D) spatial configuration and morphometrics, i.e.&#160;geometric relationship of the tooth with the alveolar socket, and 3) changes in readouts 1 and 2 due to a change in loading axis, i.e. concentric or eccentric loads.

In-situ-Druckbelastung und Correlative Nichtinvasive Bildgebung des Knochen parodontalen Ligament-Zahn-Faser-Joint

This study demonstrates a novel biomechanics testing protocol. The advantage of this protocol includes the use of an in situ loading device coupled to a ...

Forschung

Biotechnik

Measuring the Complete-arch Distortion of an Optical Dental Impression

Digital workflows have actively been used to produce dental restorations or oral appliances since dentists started to make digital impressions by acquiring 3D images with an intraoral scanner. Because of the nature of scanning the oral cavity in the patient&#39;s mouth, the intraoral scanner is a handheld device with a small optical window, stitching together small data to complete the entire image. During the complete-arch impression procedure, a deformation of the impression body can occur and affect the fit of the restoration or appliance. In order to measure these distortions, a master specimen was designed and produced with a metal 3D printer. Designed reference geometries allow setting independent coordinate systems for each impression and measure x, y, and z displacements of the cylinder top circle center where the distortion of the impression can be evaluated. In order to evaluate the reliability of this method, the coordinate values of the cylinder are calculated and compared between the original computer-aided design (CAD) data and the reference data acquired with the industrial scanner. The coordinate differences between the two groups were mostly less than 50 &#181;m, but the deviations were high due to the tolerance of 3D printing in the z coordinates of the obliquely designed cylinder on the molar. However, since the printed model sets a new standard, it does not affect the results of the test evaluation. The reproducibility of the reference scanner is 11.0 &#177; 1.8 &#181;m. This test method can be used to identify and improve upon the intrinsic problems of an intraoral scanner or to establish a scanning strategy by measuring the degree of distortion at each part of the complete-arch digital impression.

Here, we present a protocol to measure the degree of distortion at each part of the compete-arch digital impression acquired from an intraoral scanner with 3D-printed metal phantom with standard geometries.

Messen der Komplettbogenverzerrung eines optischen Zahnabdrucks

Digital workflows have actively been used to produce dental restorations or oral appliances since dentists started to make digital impressions by ...

Ingenieurwesen

Accuracy in Dental Medicine, A New Way to Measure Trueness and Precision

Reference scanners are used in dental medicine to verify a lot of procedures. The main interest is to verify impression methods as they serve as a base for dental restorations. The current limitation of many reference scanners is the lack of accuracy scanning large objects like full dental arches, or the limited possibility to assess detailed tooth surfaces. A new reference scanner, based on focus variation scanning technique, was evaluated with regards to highest local and general accuracy. A specific scanning protocol was tested to scan original tooth surface from dental impressions. Also, different model materials were verified. The results showed a high scanning accuracy of the reference scanner with a mean deviation of 5.3 &#177; 1.1 &#181;m for trueness and 1.6 &#177; 0.6 &#181;m for precision in case of full arch scans. Current dental impression methods showed much higher deviations (trueness: 20.4 &#177; 2.2 &#181;m, precision: 12.5 &#177; 2.5 &#181;m) than the internal scanning accuracy of the reference scanner. Smaller objects like single tooth surface can be scanned with an even higher accuracy, enabling the system to assess erosive and abrasive tooth surface loss. The reference scanner can be used to measure differences for a lot of dental research fields. The different magnification levels combined with a high local and general accuracy can be used to assess changes of single teeth or restorations up to full arch changes.

Accuracy is a major demand in dental medicine. To verify accuracy, reference scanners are needed. This article presents a new reference scanner with an adjusted scanning method to acquire a broad variety of dental morphologies with high trueness and precision.

Genauigkeit in Zahnmedizin, einen neuen Weg zu Richtigkeit und Präzision messen

Reference scanners are used in dental medicine to verify a lot of procedures. The main interest is to verify impression methods as they serve as a base ...

Medizin

Confocal Time Lapse Imaging as an Efficient Method for the Cytocompatibility Evaluation of Dental Composites

It is generally accepted that in vitro cell material interaction is a useful criterion in the evaluation of dental material biocompatibility. The objective of this study was to use 3D CLSM time lapse confocal imaging to assess the in vitro biocompatibility of dental composites. This method provides an accurate and sensitive indication of viable cell rate in contact with dental composite extracts. The ELS extra low shrinkage, a dental composite used for direct restoration, has been taken as example. In vitro assessment was performed on cultured primary human gingival fibroblast cells using Live/Dead staining. Images were obtained with the FV10i confocal biological inverted system and analyzed with the FV10-ASW 3.1 Software. Image analysis showed a very slight cytotoxicity in the presence of the tested composite after 5 hours of time lapse. A slight decrease of cell viability was shown in contact with the tested composite extracts compared to control cells. The findings highlighted the use of 3D CLSM time lapse imaging as a sensitive method to qualitatively and quantitatively evaluate the biocompatibility behavior of dental composites.

The most studied aspect of the biocompatibility of dental composites is their cytotoxicity 3D CLSM time lapse imaging combined with fluorescent signal quantification allows sensitive evaluation of the cell fate over time. Utilizing this method could be an efficient tool to assess the cytocompatibility of dental composites.

Konfokale Zeitraffer Imaging als eine effiziente Methode für die Bewertung der Cytocompatibility Dental Composites

It is generally accepted that in vitro cell material interaction is a useful criterion in the evaluation of dental material biocompatibility. The ...

Ratiometric Imaging of Extracellular pH in Dental Biofilms

The pH in bacterial biofilms on teeth is of central importance for dental caries, a disease with a high worldwide prevalence. Nutrients and metabolites are not distributed evenly in dental biofilms. A complex interplay of sorption to and reaction with organic matter in the biofilm reduces the diffusion paths of solutes and creates steep gradients of reactive molecules, including organic acids, across the biofilm. Quantitative fluorescent microscopic methods, such as fluorescence life time imaging or pH ratiometry, can be employed to visualize pH in different microenvironments of dental biofilms. pH ratiometry exploits a pH-dependent shift in the fluorescent emission of pH-sensitive dyes. Calculation of the emission ratio at two different wavelengths allows determining local pH in microscopic images, irrespective of the concentration of the dye. Contrary to microelectrodes the technique allows monitoring both vertical and horizontal pH gradients in real-time without mechanically disturbing the biofilm. However, care must be taken to differentiate accurately between extra- and intracellular compartments of the biofilm. Here, the ratiometric dye, seminaphthorhodafluor-4F 5-(and-6) carboxylic acid (C-SNARF-4) is employed to monitor extracellular pH in in vivo grown dental biofilms of unknown species composition. Upon exposure to glucose the dye is up-concentrated inside all bacterial cells in the biofilms; it is thus used both as a universal bacterial stain and as a marker of extracellular pH. After confocal microscopic image acquisition, the bacterial biomass is removed from all pictures using digital image analysis software, which permits to exclusively calculate extracellular pH. pH ratiometry with the ratiometric dye is well-suited to study extracellular pH in thin biofilms of up to 75 &#181;m thickness, but is limited to the pH range between 4.5 and 7.0.

A pH-sensitive ratiometric dye is used in combination with confocal laser scanning microscopy and digital image analysis to monitor extracellular pH in dental biofilms in real-time.

Ratiometrisch Imaging von extrazellulären pH in Dental Biofilme

The pH in bacterial biofilms on teeth is of central importance for dental caries, a disease with a high worldwide prevalence. Nutrients and metabolites ...

Immunologie und Infektion

Roughness Impact of Piezoelectric Dental Scaler on Two Distinct Flowable Composite Filling Materials

Dental ultrasonic scalers are commonly employed in periodontal treatment; however, their ability to roughen tooth surfaces is a worry since roughness may increase plaque production, a key cause of periodontal disease. This research studied the influence of a piezoelectric ultrasonic scaler on the roughness of two distinct flowable composite filling materials. To do this, 10 disc-shaped samples were generated from each of the two flowable composite materials. After standardized polishing, samples were submerged in water for 24 h before the first surface examination using electron microscopy and profilometry. The ultrasonic scaler was applied to a specified location of each sample for 60 s under water cooling and regulated force. Post-scaler surface parameters were again examined. Following the application of the scaler, both composite materials exhibited a notable increase in surface roughness, as determined by profilometry (p &lt; 0.01). Additionally, the observed surface roughness was also qualitatively visualized with scanning electron microscopy. While initial roughness levels were comparable across the two composites (p = 0.143) after scaler application, no substantial discrepancy in surface texture was noticed between them (p = 0.684). The use of a high-power piezoelectric ultrasonic scaler on routinely used flowable composite restorations might generate considerable surface roughness, possibly leading to increased plaque accumulation. Nevertheless, it might be postulated that nanohybrid flowable composite materials having conventional monomer ingredients may demonstrate comparable surface alterations within the limitations of this experiment.

This methodology allows applying a dental appliance on any specimen at any angle with standardized force and stability. This approach might be extensively used in health sciences to standardize the impacts of dental equipment with hand-holding elements such as micromotors, turbines, and ultrasonic scalers on varied surfaces.

Einfluss des piezoelektrischen Dentalscalers auf die Rauheit von zwei unterschiedlichen fließfähigen Komposit-Füllungsmaterialien

Dental ultrasonic scalers are commonly employed in periodontal treatment; however, their ability to roughen tooth surfaces is a worry since roughness may ...

Verhalten

3D Imaging of PDL Collagen Fibers during Orthodontic Tooth Movement in Mandibular Murine Model

Orthodontic tooth movement is a complex biological process of altered soft and hard tissue remodeling as a result of external forces. In order to understand these complex remodeling processes, it is critical to study the tooth and periodontal tissues within their 3D context and therefore minimize any sectioning and tissue artefacts. Mouse models are often utilized in developmental and structural biology, as well as in biomechanics due to their small size, high metabolic rate, genetics and ease of handling. In principle this also makes them excellent models for dental related studies. However, a major impediment is their small tooth size, the molars in particular. This paper is aimed at providing a step by step protocol for generating orthodontic tooth movement and two methods for 3D imaging of the periodontal ligament fibrous component of a mouse mandibular molar. The first method presented is based on a micro-CT setup enabling phase enhancement&#160;imaging of fresh collagen tissues. The second method is a bone clearing method using ethyl cinnamate that enables imaging through the bone without sectioning and preserves endogenous fluorescence. Combining this clearing method with reporter mice like Flk1-Cre;TdTomato provided a first of its kind opportunity to image the 3D vasculature in the PDL and alveolar bone.

We present a protocol for generating orthodontic tooth movement in mice and methods for 3D visualization of the collagen fibers and blood vessels of periodontal ligament without sectioning.

3D-Bildgebung von PDL-Kollagenfasern während kieferorthopädischer Zahnbewegungen im Unterkiefermine modell

Orthodontic tooth movement is a complex biological process of altered soft and hard tissue remodeling as a result of external forces. In order to ...

Detection and Removal of Tooth-Colored Composite Resin Using the Fluorescence-Aided Identification Technique

The detection and removal of tooth-colored filling materials is a major challenge for every dentist. The Fluorescence-aided Identification Technique (FIT) is a noninvasive tool to facilitate the distinction of composite resin material from sound tooth substance. Compared to conventional illumination, FIT is a very accurate, reliable, and fast diagnostic method. When composite resin is illuminated with a wavelength of approximately 398 &plusmn; 5 nm, certain fluorescent components make the composite resin appear brighter than the tooth structure. Any fluorescence-inducing light source with the appropriate wavelength can be used for this method. Optimally, this technique is used without additional natural or artificial lighting. The application of FIT can be used for diagnostic purposes, for example, dental charts, and additionally for the complete and minimally invasive removal of composite resin restorations, bracket debonding, and trauma splint removal. The assessment of volumetric changes after composite removal can be provided by overlapping pre- and postoperative scans and subsequent calculation using suitable software.

The Fluorescence-aided Identification Technique is a practicable, fast, and reliable approach for the differentiation of composite resin restorations from tooth substance, and facilitates the minimally invasive and complete removal of composite resin restorations and composite bonded trauma splints.

Detektion und Entfernung von zahnfarbenem Kompositharz mittels fluoreszenzgestützter Identifikationstechnik

The detection and removal of tooth-colored filling materials is a major challenge for every dentist. The Fluorescence-aided Identification Technique (FIT) ...

Precision of In Vivo Quantitative Tooth Wear Measurement Using Intra-Oral Scans

Quantitative wear measurement is of increasing interest for measuring tooth wear progression. However, most research on quantitative wear measurement has focused on simulated wear or scanned gypsum casts. A 3D Wear Analysis (3DWA) protocol has been developed that analyzes tooth wear in vivo through intra-oral scanners available to dental clinicians. This study investigated the precision of the 3DWA protocol for measuring wear through maximum height loss (mm) and volume change (mm3). Observational prospective wear data from 55 patients were analyzed after 0-1-, 0-3-, and 0-5-year intervals to determine rates of wear, and convenience samples were chosen to test the protocol&#39;s precision on dentitions scanned twice in one sitting and its intra- and inter-rater precision on scans with 0-3- and 0-5-year intervals. Scans were made using intra-oral scanners (IOS) and superimposed using 3D measurement software. T-tests were performed to determine the structural and random error, and trimmed ranges were calculated to interpret the error. For protocol precision, the mean difference was 0.015 mm (-0.002; 0.032, p = 0.076) for height and -0.111 mm3 (-0.250; 0.023, p = 0.101) for volume. The duplicate measurement error was 0.062 mm for height and 0.268 mm3 for volume. The height measurements were precise enough to measure wear after intervals of 0-3 or 0-5 years; however, volume measurements were susceptible to procedural error and operator sensitivity. The 3DWA protocol is precise enough to adequately measure tooth height loss after intervals of a minimum of 3 years or in patients with severe wear progression, but it is not suited to measuring volumetric changes.

Precision of In Vivo Quantitative Tooth Wear Measurement Using Intra-Oral Scans

Quantitative wear measurement is a method of increasing importance in measuring tooth wear progression. We here describe a protocol, its precision, and its intra/inter-rater precision for the acquisition and superimposition of repeated in vivo scanned dentitions in patients with moderate to severe wear, reporting on both height and volume measurements.

Präzision der quantitativen In-vivo-Zahnverschleißmessung mittels intraoraler Scans

Quantitative wear measurement is of increasing interest for measuring tooth wear progression. However, most research on quantitative wear measurement has ...

Semi-Automated Planimetric Quantification of Dental Plaque Using an Intraoral Fluorescence Camera

Dental plaque accumulation is quantified using clinical indices or, otherwise, the planimetric plaque index (PPI),&#160;which measures the relative area of a tooth that is covered by plaque deposits. Compared to clinical indices, the PPI has a higher discriminatory power, but traditional planimetry is a time-consuming analysis, as the plaque-covered and clean tooth areas have to be determined manually for each image using image-processing software. Here, we present a method for the semi-automated planimetric quantification of dental plaque, which allows for the rapid processing of up to 1,000 images simultaneously. The method exploits the enhanced contrast between disclosed plaque, sound tooth surfaces, and soft tissues in fluorescence images acquired with an intraoral camera. Careful execution of the clinical procedures and accurate image acquisition are crucial steps for the successful semi-automated identification of the plaque-covered areas. The method is suitable for planimetry on sound facial and oral tooth surfaces, on most composite resin restorations, and on teeth with orthodontic brackets, but not on metallic restorations. Compared to traditional PPI recordings, semi-automated planimetry considerably reduces the amount of time spent on the analysis, as well as the subjective human input, thus increasing the reproducibility of planimetric measurements.

This study presents a semi-automated digital image analysis procedure for the planimetric quantification of disclosed dental plaque based on images acquired with an intraoral fluorescence camera. The method allows for the rapid and reliable quantification of dental plaque in the research environment.

Halbautomatische planimetrische Quantifizierung von Zahnbelag mittels intraoraler Fluoreszenzkamera

Dental plaque accumulation is quantified using clinical indices or, otherwise, the planimetric plaque index (PPI),&#160;which measures the relative area ...