Publications by authors named "Christian Hannig"

105 Publications

Modification of the Lipid Profile of the Initial Oral Biofilm In Situ Using Linseed Oil as Mouthwash.

Nutrients 2021 Mar 19;13(3). Epub 2021 Mar 19.

Clinic of Operative Dentistry, Periodontology and Preventive Dentistry, University Hospital, Saarland University, Building 73, D-66421 Homburg, Germany.

Lipids are of interest for the targeted modification of oral bioadhesion processes. Therefore, the sustainable effects of linseed oil on the composition and ultrastructure of the in situ pellicle were investigated. Unlike saliva, linseed oil contains linolenic acid (18:3), which served as a marker for lipid accumulation. Individual splints with bovine enamel slabs were worn by five subjects. After 1 min of pellicle formation, rinses were performed with linseed oil for 10 min, and the slabs' oral exposure was continued for up to 2 or 8 h. Gas chromatography coupled with electron impact ionization mass spectrometry (GC-EI/MS) was used to characterize the fatty acid composition of the pellicle samples. Transmission electron microscopy was performed to analyze the ultrastructure. Extensive accumulation of linolenic acid was recorded in the samples of all subjects 2 h after the rinse and considerable amounts persisted after 8 h. The ultrastructure of the 2 h pellicle was less electron-dense and contained lipid vesicles when compared with controls. After 8 h, no apparent ultrastructural effects were visible. Linolenic acid is an excellent marker for the investigation of fatty acid accumulation in the pellicle. New preventive strategies could benefit from the accumulation of lipid components in the pellicle.
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http://dx.doi.org/10.3390/nu13030989DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003129PMC
March 2021

Mapping of the Micro-Mechanical Properties of Human Root Dentin by Means of Microindentation.

Materials (Basel) 2021 Jan 21;14(3). Epub 2021 Jan 21.

Clinic of Operative and Pediatric Dentistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany.

The extensive knowledge of root dentin's mechanical properties is necessary for the prediction of microstructural alterations and the teeth's deformations as well as their fracture behavior. Standardized microindentation tests were applied to apical, medial, and cervical root sections of a mandibular human first molar to determine the spatial distribution of the hard tissue's properties (indentation modulus, indentation hardness, Martens hardness, indentation creep). Using an indentation mapping approach, the inhomogeneity of mechanical properties in longitudinal as well as in transversal directions were measured. As a result, the tooth showed strongly inhomogeneous material properties, which depended on the longitudinal and transversal positions. In the transversal cutting planes of the cervical, medial, apical sections, the properties showed a comparable distribution. A statistical evaluation revealed an indentation modulus between 12.2 GPa and 17.8 GPa, indentation hardness between 0.4 GPa and 0.64 GPa and an indentation creep between 8.6% and 10.7%. The established standardized method is a starting point for further investigations concerning the intensive description of the inhomogeneous mechanical properties of human dentin and other types of dentin.
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http://dx.doi.org/10.3390/ma14030505DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7864522PMC
January 2021

Quantification of Bacterial Colonization in Dental Hard Tissues Using Optimized Molecular Biological Methods.

Front Genet 2020 18;11:599137. Epub 2020 Dec 18.

Clinic of Operative and Pediatric Dentistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.

Bacterial infections of root canals and the surrounding dental hard tissue are still a challenge due to biofilm formation as well as the complex root canal anatomy. However, current methods for analyzing biofilm formation, bacterial colonization of root canals and dental hard tissue [e.g., scanning electron microscopy, confocal laser scanning microscopy (CLSM) or determination of colony forming units (CFU)] are time-consuming and only offer a selective qualitative or semi-quantitative analysis. The aim of the present study is the establishment of optimized molecular biological methods for DNA-isolation and quantification of bacterial colonization via quantitative PCR (qPCR) from dental hard tissue. Root canals of human premolars were colonized with . For isolation of DNA, teeth were then grinded with a cryo mill. Since the hard tissues dentin and especially enamel belong to the hardest materials in the human organism, the isolation of bacterial DNA from root dentin is very challenging. Therefore, treatment steps for the isolation of DNA from grinded teeth were systematically analyzed to allow improved recovery of bacterial DNA from dental hard tissues. Starting with the disintegration of the peptidoglycan-layer of bacterial cells, different lysozyme solutions were tested for efficacy. Furthermore, incubation times and concentrations of chelating agents such as EDTA were optimized. These solutions are crucial for the disintegration of teeth and hence improve the accessibility of bacterial DNA. The final step was the determination of prior bacterial colonization of each root canal as determined by qPCR and comparing the results to alternative methods such as CFU. As a result of this study, optimized procedures for bacterial DNA-isolation from teeth were established, which result in an increased recovery rate of bacterial DNA. This method allows a non-selective and straightforward procedure to quantify bacterial colonization from dental hard tissue. It can be easily adapted for other study types such as microbiome studies and for comparable tissues like bones.
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http://dx.doi.org/10.3389/fgene.2020.599137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7775318PMC
December 2020

Bioadhesion in the oral cavity and approaches for biofilm management by surface modifications.

Clin Oral Investig 2020 Dec 27;24(12):4237-4260. Epub 2020 Oct 27.

Clinic of Operative Dentistry, Periodontology and Preventive Dentistry, University Hospital, Saarland University, Building 73, 66421, Homburg/Saar, Germany.

Background: All soft and solid surface structures in the oral cavity are covered by the acquired pellicle followed by bacterial colonization. This applies for natural structures as well as for restorative or prosthetic materials; the adherent bacterial biofilm is associated among others with the development of caries, periodontal diseases, peri-implantitis, or denture-associated stomatitis. Accordingly, there is a considerable demand for novel materials and coatings that limit and modulate bacterial attachment and/or propagation of microorganisms.

Objectives And Findings: The present paper depicts the current knowledge on the impact of different physicochemical surface characteristics on bioadsorption in the oral cavity. Furthermore, it was carved out which strategies were developed in dental research and general surface science to inhibit bacterial colonization and to delay biofilm formation by low-fouling or "easy-to-clean" surfaces. These include the modulation of physicochemical properties such as periodic topographies, roughness, surface free energy, or hardness. In recent years, a large emphasis was laid on micro- and nanostructured surfaces and on liquid repellent superhydrophic as well as superhydrophilic interfaces. Materials incorporating mobile or bound nanoparticles promoting bacteriostatic or bacteriotoxic properties were also used. Recently, chemically textured interfaces gained increasing interest and could represent promising solutions for innovative antibioadhesion interfaces. Due to the unique conditions in the oral cavity, mainly in vivo or in situ studies were considered in the review.

Conclusion: Despite many promising approaches for modulation of biofilm formation in the oral cavity, the ubiquitous phenomenon of bioadsorption and adhesion pellicle formation in the challenging oral milieu masks surface properties and therewith hampers low-fouling strategies.

Clinical Relevance: Improved dental materials and surface coatings with easy-to-clean properties have the potential to improve oral health, but extensive and systematic research is required in this field to develop biocompatible and effective substances.
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http://dx.doi.org/10.1007/s00784-020-03646-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7666681PMC
December 2020

Results of a randomized controlled phase III trial: efficacy of polyphenol-containing cystus® tea mouthwash solution for the reduction of mucositis in head and neck cancer patients undergoing external beam radiotherapy.

Strahlenther Onkol 2021 Jan 24;197(1):63-73. Epub 2020 Sep 24.

German Cancer Research Center (DKFZ), Heidelberg, Germany.

Purpose: To determine the effect of Cystus® tea (Naturprodukte Dr. Pandalis GmbH & Co. KG) as mouthwash compared to sage tea on oral mucositis in patients undergoing radio(chemo)therapy for head and neck cancer.

Methods: In this randomized, prospective phase III study, 60 head and neck cancer patients with primary or postoperative radio(chemo)therapy were included between 04/2012 and 06/2014. They received either sage or Cystus® tea for daily mouthwash under therapy. Mucositis was scored twice a week following the Radiation Therapy Oncology Group and the European Organization for Research and Treatment Cancer (RTOG/EORTC) scoring system. Dental parameters were also recorded. Statistical evaluation of the primary endpoint was performed using t‑test and log rank test.

Results: Data from 57 patients could be evaluated. Patient characteristics showed no significant difference between the two groups (n = 27 sage; n = 30 Cystus®). A total of 55 patients received the prescribed dose (60-66 Gy postoperative; 70-76.8 Gy primary). Mucositis grade 3 was observed in 23 patients (n = 11 sage; n = 12 Cystus®) and occurred between day 16 and 50 after start of therapy. There was no significant difference between the two groups in latency (p = 0.75) and frequency (p = 0.85) of the occurrence of mucositis grade 3. The self-assessment of the oral mucosa and the tolerability of the tea also showed no significant differences. Occurrence of dental pathologies appeared to increase over time after radiotherapy.

Conclusion: Cystus® and sage tea have a similar effect on the occurrence of radiation-induced mucositis regarding latency and incidence. Cystus® tea mouthwash solution is tolerated well and can be applied in addition to intensive oral care and hygiene along with the application of fluorides.
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http://dx.doi.org/10.1007/s00066-020-01684-yDOI Listing
January 2021

Effect of fragaria vesca, hamamelis and tormentil on the initial bacterial colonization in situ.

Arch Oral Biol 2020 Oct 3;118:104853. Epub 2020 Aug 3.

Clinic of Operative Dentistry, Periodontology and Preventive Dentistry, University Hospital, Saarland University, Building 73, D- 66421, Homburg, Saar, Germany.

Objective: The presentin situ study aims to examine the influence of the polyphenolic tea drugs fragaria vesca, hamamelis and tormentil on the initial oral bioadhesion.

Design: Initial biofilm formation was performed on bovine enamel slabs which were carried intraorally by 12 subjects. After 1 min of intraoral pellicle formation, the subjects rinsed with fragaria vesca, tormentil (0.8 mg/8 mL) and hamamelis (0.2 mg/8 mL) for 10 min. Tap water served as negative control, 0.2 % CHX as positive control. The investigations took place on different days (wash-out: 2 days). Afterwards, fluorescence microscopy has been performed per test solution (n = 5) and per subject (n = 12) to visualize bacterial adhesion and glucan formation (8 h oral exposition) with DAPI, ConA and BacLight. Additionally, TEM was used to visualize the pellicle ultrastructure and expectorate samples. Statistical evaluation was carried out using the Kruskal-Wallis- (p < 0.5), Mann-Whitney U test (p < 0.5) and Bonferroni-Holm-correction (p < 0.1).

Results: Rinsing with the polyphenolic tea extracts reduced significantly initial bacterial colonization (DAPI) compared to the negative control. There was no significant difference betweenfragaria vesca, hamamelis and tormentil. All solutions showed a reducing effect on the glucan formation. No significant difference was observed between fragaria vesca and CHX. Considerable alterations of the pellicle's ultrastructure manifested by an increase in thickness and electron density resulted from rinsing with the three polyphenolic aqueous extracts.

Conclusions: Fragaria vesca, hamamelis and tormentil significantly reduce initial bioadhesion and glucan formation in situ and are therefore recommended as adjuvant antibacterial oral therapeutics.
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http://dx.doi.org/10.1016/j.archoralbio.2020.104853DOI Listing
October 2020

Author Correction: Influence of pure fluorides and stannous ions on the initial bacterial colonization in situ.

Sci Rep 2020 Mar 25;10(1):5695. Epub 2020 Mar 25.

Clinic of Operative Dentistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, D-01307, Dresden, Germany.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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http://dx.doi.org/10.1038/s41598-020-62064-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7096531PMC
March 2020

Continuous Measurement of Three-Dimensional Root Canal Curvature Using Cone-Beam Computed and Micro-Computed Tomography: A Comparative Study.

Dent J (Basel) 2020 Feb 6;8(1). Epub 2020 Feb 6.

Clinic of Operative and Pediatric Dentistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany.

The knowledge of root canal curvature is crucial regarding the prevention of ledge formation, root perforation and the possibility of endodontic instruments' fracture during endodontic treatments. Therefore, a quantification method of the root canal curvature as well as the applicability of diagnostically relevant tomographic three-dimensional (3D) imaging data is necessary. Hereby, cone-beam computed tomography (CBCT) images and micro-computed tomography (µCT) data of distal root canals were analysed concerning the continuous three-dimensional curvature of human mandibular molars ( n = 50). The curvature of the canal's three-dimensional centre line was determined by evaluating the tomographic images. The centroids of each root canal slice were identified and approximated by spline curves to obtain the centre line and therefore, its curvature. Comparing the results evaluated from CBCT and µCT images, minimum radii of curvature of 2.6 mm and 2.1 mm were determined, respectively. The observation of the centre line demonstrated the requirement of the three-dimensional imaging data from CBCT and µCT for a reliable curvature analysis. Conclusively, the evaluation of CBCT and µCT images results in comparable radii of curvature. Thus, the application of the introduced method in combination with CBCT applied to patient cases could offer an important preliminary diagnostical step to prevent endodontic treatment complications.
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http://dx.doi.org/10.3390/dj8010016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7148492PMC
February 2020

Targeted metabolomics of pellicle and saliva in children with different caries activity.

Sci Rep 2020 01 20;10(1):697. Epub 2020 Jan 20.

Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich, Lise-Meitner-Straße 34, D-85354, Freising, Germany.

Pellicle is the initial proteinaceous layer that is formed almost instantaneously on all solid surfaces in the oral cavity. It is of essential relevance for any interactions and metabolism on the tooth surface. Up to now, there is no information on the metabolome of this structure. Accordingly, the present study aims to characterise the metabolomic profile of in-situ pellicle in children with different caries activity for the first time in comparison to saliva. Small molecules such as carbohydrates, amino acids, organic acids, and fatty acids, putatively involved in the formation of caries were quantified using mass spectrometry (MS)-based techniques, such as (stable isotope dilution analysis)-ultra-performance liquid chromatography-tandem MS and gas chromatography/electron ionisation-MS. Pellicle and corresponding saliva samples were collected from caries-active, caries-free and caries-rehabilitated 4- to 6-year-old children. The most abundant analytes in pellicle were acetic acid (1.2-10.5 nmol/cm), propionic acid (0.1-8.5 nmol/cm), glycine (0.7-3.5 nmol/cm), serine (0.08-2.3 nmol/cm), galactose (galactose + mannose; 0.035-0.078 nmol/cm), lactose (0.002-0.086 nmol/cm), glucose (0.018-0.953 nmol/cm), palmitic acid (0.26-2.03 nmol/cm), and stearic acid (0.34-1.81 nmol/cm). Significant differences depending on caries activity were detected neither in saliva nor in the corresponding pellicle samples.
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http://dx.doi.org/10.1038/s41598-020-57531-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6971297PMC
January 2020

Caries and periodontitis associated bacteria are more abundant in human saliva compared to other great apes.

Arch Oral Biol 2020 Mar 2;111:104648. Epub 2020 Jan 2.

Faculty of Biology, Institute of Zoology, Molecular Cell Physiology and Endocrinology, Technische Universität Dresden, 01217 Dresden, Germany. Electronic address:

Objective: Caries and periodontitis are uncommon in free ranging great apes but a major oral disease in humans. The aim was to analyze abundance and diversity of oral bacteria of western humans and their closest relatives, to examine if zoo apes feeding on diet other than in their natural habitat show caries and periodontitis associated salivary bacteria and comparable susceptibility for oral civilization diseases as humans.

Design: Bacterial composition of human and great ape saliva samples were compared by analyzing the V3 region of the bacteria 16S rRNA gene by Next Generation Sequencing with Ion Torrent.

Results: Results show species-specific differences in the salivary bacteria phyla and genera composition among all apes. Moreover, salivary bacterial composition within non-human apes showed higher intra-individual differences than within humans. Human saliva exhibited lowest bacteria diversity. Different behavioral patterns including (oral) hygiene standards of humans and non-human apes might cause differences. All species differed in diversity and abundance of caries associated bacteria genera. Human saliva revealed higher abundance of caries and periodontitis relevant bacteria in contrast to other great apes, which might be supported by higher consume of refined cariogenic food items, possibly raising their risk for oral disease susceptibility.

Conclusions: The study offers first clues on caries and periodontitis relevant bacteria of captive great ape species in comparison to humans. Higher susceptibility to oral diseases for humans than for their closest relatives, leads to the question, if the oral microbiome changed during evolution and how it is influenced by the human life style.
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http://dx.doi.org/10.1016/j.archoralbio.2020.104648DOI Listing
March 2020

Influence of pure fluorides and stannous ions on the initial bacterial colonization in situ.

Sci Rep 2019 12 6;9(1):18499. Epub 2019 Dec 6.

Clinic of Operative Dentistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, D-01307, Dresden, Germany.

The present clinical-experimental study aims to examine the effect of pure experimental fluoride solutions and stannous chloride on the initial oral bioadhesion under in situ conditions. After 1 min of pellicle formation on bovine enamel slabs, 12 subjects rinsed with 8 ml of the fluoride test solutions (NaF, NaPOF, AmF, SnF,) with 500 ppm fluoride concentration each for 1 min. Additionally, rinsing without a solution (control) and rinsing with 1563 ppm SnCl solution took place for 1 min. Afterwards, fluorescence microscopy took place to visualize bacterial adhesion and glucan formation (8 h oral exposition) with DAPI and ConA and the BacLight method. TEM was performed to visualize the pellicle ultrastructure together with EDX to detect stannous ions. The rinsing solutions with pure SnF and SnCl reduced significantly the initial bacterial colonization (DAPI). While, NaF and NaPOF showed no significant effect compared to the control. There was no significant difference between AmF, SnF and SnCl. All tested experimental solutions showed no reducing effect on the glucan formation. Considerable alterations of the pellicle ultrastructure resulted from rinsing with the Sn-containing solutions. SnF appears to be the most effective type of fluoride to reduce initial bacterial colonization in situ. The observed effects primarily have to be attributed to the stannous ions' content.
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http://dx.doi.org/10.1038/s41598-019-55083-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6898421PMC
December 2019

The association between socioeconomic status, psychopathological symptom burden in mothers, and early childhood caries of their children.

PLoS One 2019 28;14(10):e0224509. Epub 2019 Oct 28.

Department of Psychotherapy and Psychosomatic Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.

Objectives: Various maternal mental disorders and socioeconomic status [SES] are discussed as risk factors for early childhood caries [ECC]. In our study, we examined a wide range of symptoms of mental disorders with the aim to identify those maternal psychopathological symptom burdens [PSBs] which show relevant associations with ECC. Our second objective was to investigate how SES affects the associations between PSB and ECC.

Methods: In this study, sixty children with ECC (caries group [CG]) and sixty caries-free children [NON-CG] with their mothers were recruited at two sites in Germany. Children aged three or four years were included in the study. Children's dental status [dmf-t] and plaque index were recorded, and mothers answered a multidimensional SES index (including education, profession and income) as well as screening questionnaires capturing dental anxiety, depressive disorders, generalized anxiety, somatic symptom burden, eating disorders, traumatic childhood experiences, nicotine dependency and alcohol dependency.

Results: Mothers of the CG reported significantly higher dental anxiety (dCohen = 0.66), childhood trauma (dCohen = 0.53) and nicotine dependency (dCohen = 0.64) than the NON-CG. However, mediator analyses showed that these effects were partly mediated by the SES. Mothers of the CG had a significantly lower SES (dCohen = 0.93); with education as strongest predictor of dental status. The groups did not differ significantly in symptoms of depressiveness, subjective somatic symptom burden, alcohol dependency, eating disorders, and generalized anxiety.

Conclusions: Several PSBs are associated with ECC, however the SES as the strongest influencing factor mediates this association. Difficult socioeconomic conditions might predispose for both, ECC and mental illness. Targeted strategies are needed to facilitate the use of preventive measures and dental health services especially in families of lower status. For this purpose, psychosocial risk constellations must be identified. More integrative, multifactorial oriented research is necessary to gain a bio-psycho-social understanding of ECC.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0224509PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6816547PMC
March 2020

Activity and distribution pattern of enzymes in the in-situ pellicle of children.

Arch Oral Biol 2019 Aug 22;104:24-32. Epub 2019 May 22.

Clinic of Operative Dentistry, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany.

Objective: This study investigated, for the first time, pellicle enzymes with respect to their activity, distribution and fluorescence pattern in children with different caries experience.

Design: In-situ pellicles were collected from 41 children (aged 4-6 years) with different caries status; 17 of them were caries-free (dmf = 0), 12 had dental restorations but no current caries (dmf ≥ 2) and 12 had at least two carious lesions (dmf ≥ 2). Bovine enamel samples were fixed on individual upper jaw braces for pellicle formation. After 30 min of intraoral exposure, the pellicle and saliva samples were analysed for the activities of amylase, lysozyme, peroxidase and glucosyltransferase (GTF). The distribution of these enzymes, including GTF-isoforms B, C and D, and the pellicle ultrastructure were examined by gold-immunolabelling and transmission electron microscopy (TEM). Furthermore, interactions between pellicle enzymes and adherent bacteria were visualised using combined fluorescence and immunofluorescence labelling.

Results: There were no significant differences in the pellicle enzyme activities between the study groups. TEM analysis revealed the absence of GTF C and D in the pellicle of caries-active children. Amylase, peroxidase and GTF-isoforms showed a random distribution within the pellicle layer; lysozyme was found in the form of clusters. A similar ultrastructural pattern was observed for all subjects. Fluorescence labelling technique enabled visualisation of all enzymes, except for GTF B.

Conclusion: Pellicle enzyme activities and ultrastructure are not associated with children's caries status. Further investigation is needed to assess the influence of individual GTF-isoforms on caries susceptibility in children.
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http://dx.doi.org/10.1016/j.archoralbio.2019.05.017DOI Listing
August 2019

Is it really penetration? Part 2. Locomotion of Enterococcus faecalis cells within dentinal tubules of bovine teeth.

Clin Oral Investig 2019 Dec 19;23(12):4325-4334. Epub 2019 Mar 19.

Clinic of Operative Dentistry, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstr.74, 01307, Dresden, Germany.

Objective: The aim of the present vitro study was to examine the question whether devitalized Enterococcus faecalis (E. faecalis) cells can migrate into dentinal tubules and if that process takes place in a time-dependent manner.

Design: Sixty bovine root canals were incubated with devitalized and vital streptomycin-resistant E. faecalis strains after root canal enlargement (size 80, taper .02) with 3% NaOCl solution. Incubation times 7, 14, 21, 28, 35, and 42 days. Samples were processed for analysis by scanning electron microscopy (SEM) and DAPI (4',6-diamidino-2-phenylindole) staining. The penetration depth was calculated with the measurement tool of the Axio Vision program (Zeiss, Jena, Germany). Statistical analysis was performed by Kruskal-Wallis (α = 0.05) and Mann-Whitney U test (p < 0.05).

Results: Devitalized E. faecalis strains were able to migrate into dentinal tubules. The total number and penetration depth of devitalized E. faecalis cells was lower compared to the vital suspension of E. faecalis. It was noted, that bacterial penetration was not common to all of the dentinal tubules in the vital E. faecalis control and especially in the devitalized control. The migration took place in a time-dependent migration characteristic.

Conclusions: Devitalized E. faecalis cells are still able to migrate into the dentinal tubules due to possible electrokinetic and osmotic processes. Thereby, increased exposure times lead to a time-dependent penetration characteristic.

Clinical Relevance: Since devitalized bacteria can migrate as well into dentinal tubules, the presence of bacteria within dentinal tubules cannot be interpreted as a failure of tested preparation regimens.
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http://dx.doi.org/10.1007/s00784-019-02865-5DOI Listing
December 2019

Effects of Endodontic Irrigants on Material and Surface Properties of Biocompatible Thermoplastics.

Dent J (Basel) 2019 Mar 6;7(1). Epub 2019 Mar 6.

Clinic of Operative and Pediatric Dentistry, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany.

Passive irrigation is an efficient method for a successful endodontic treatment. During sonic activation biocompatible polymer tips are used to activate irrigants. Compared to ultrasonic activation with metallic tips, polymer tips have the advantage of a reduced risk of fracture and minimise dentine damage. Hence, two polymers, polyether ether ketones (PEEK) and polyamide (PA6), were identified for the manufacturing of novel irrigation tips. The chemical resistance against the irrigants ethylenediaminetetraacetic acid (EDTA) 20%, chlorhexidine gluconate (CHX) 2% and sodium hypochlorite (NaOCl) 5.25% was analysed. Using microindentation, the change of hardness, elasticity, surface roughness and appearance of the polymers was determined. PA6 had a high absorption of irrigant compared to PEEK. PEEK was resistant to the investigated irrigants and showed no significant alteration of surface and mechanical properties, whereas PA6 slightly increased its hardness, elastic modulus and surface roughness during long-term exposure at 37 °C. However, PA6 tips seem to be a promising disposable product due to the material's high deformability and low manufacturing costs. Particularly with regard to structural-dynamic properties and high chemical resistance, PEEK can be considered as a material for reusable irrigation tips.
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http://dx.doi.org/10.3390/dj7010026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6473885PMC
March 2019

Psychological distress and anxiety compared amongst dental patients- results of a cross-sectional study in 1549 adults.

BMC Oral Health 2019 01 31;19(1):27. Epub 2019 Jan 31.

Technische Universität Dresden, Carl Gustav Carus Faculty of Medicine, Division of Psychological and Social Medicine and Developmental Neurosciences, Research Group Applied Medical Psychology and Medical Sociology, Fetscherstr. 74, 01307, Dresden, Germany.

Background: This study aimed to identify anxiety in dental patients visiting a dental clinic using the Dental Anxiety Scale, their level of psychological distress using the Brief Symptom Inventory-18 and therefore identifying a correlation between these groups as well as their gender and age.

Methods: An adult sample of N = 1549 patients (865 females, 779 males) was examined over the course of three years using the Brief Symptom Inventory-18 to evaluate psychological distress and the Dental Anxiety Scale to determine anxiety before dental treatment. Evaluations were conducted according to age and gender.

Results: There was no correlation between different age groups of the sample the Dental Anxiety Scale. Anxiety, depression and GSI were more frequent in patients below the age of 46 than above. Women were more susceptible to signs of Anxiety and Somatization and scored higher on the Dental Anxiety Scale and the Global Severity Index than male patients. There was a significant positive correlation between scores of the BSI-18 categories: Somatization, Anxiety and Depression and the DAS for dental patients.

Conclusions: This study showed that a relationship between dental anxiety and psychological distress exists. It would be an improvement to use a short questionnaire like the Dental Anxiety Scale to evaluate a patient before his first treatment so that more appropriate treatments can be pursued.
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http://dx.doi.org/10.1186/s12903-019-0719-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6357460PMC
January 2019

Impact of a non-fluoridated microcrystalline hydroxyapatite dentifrice on enamel caries progression in highly caries-susceptible orthodontic patients: A randomized, controlled 6-month trial.

J Investig Clin Dent 2019 May 30;10(2):e12399. Epub 2019 Jan 30.

Department of Orthodontics, University Hospital Regensburg, Regensburg, Germany.

Aim: The aim of the present randomized, controlled trial was to compare the impact of the regular use of a fluoride-free microcrystalline hydroxyapatite (HAP) dentifrice and a 1400 ppm fluoride control dentifrice on caries progression in 150 highly caries-active orthodontic patients.

Methods: The primary outcome was the occurrence of lesions with International Caries Detection and Assessment System (ICDAS) ≥code 1 on the vestibular surfaces of teeth 15-25 within 168 days after fixation of orthodontic brackets. Secondary outcomes were lesion development ICDAS ≥code 2, the plaque index, and the gingival index.

Results: In total, 147 patients were included in the intent-to-treat (ITT) analysis; 133 finished the study per protocol (PP). An increase in enamel caries ICDAS ≥code 1 was observed in 56.8% (ITT) and 54.7% (PP) of the HAP group participants compared with 60.9% (ITT) and 61.6% (PP) of the fluoride control group. Non-inferiority testing (ITT and PP) demonstrated the absence of a significant difference between the groups. No significant differences in secondary outcomes were observed between the groups.

Conclusion: In highly caries-active patients, the impact of the regular use of a microcrystalline HAP dentifrice on caries progression is not significantly different from the use of a 1400 ppm fluoride toothpaste (ClinicalTrials.gov: NCT02705456).
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http://dx.doi.org/10.1111/jicd.12399DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6590169PMC
May 2019

Proteomic Analysis of the Initial Oral Pellicle in Caries-Active and Caries-Free Individuals.

Proteomics Clin Appl 2019 07 19;13(4):e1800143. Epub 2018 Dec 19.

Clinic of Operative Dentistry, Periodontology and Preventive Dentistry, University Hospital, Saarland University, Homburg/Saar, Germany.

Purpose: To 1) elucidate individual proteomic profiles of the 3-min biofilm of caries-active and caries-free individuals and 2) compare these proteomic profiles against the background of caries.

Experimental Design: The initial oral pellicle of 12 caries-active and 12 caries-free individuals is generated in situ on ceramics specimens. The individual, host-specific proteomic profiles of this basic pellicle layer are analyzed by a chemical elution protocol combined with an elaborate mass spectrometry and evaluated bioinformatically.

Results: A total of 1188 different proteins are identified. Additionally, 68 proteins are present in the profiles of all individuals, suggesting them as ubiquitously occurring base-proteins of the initial human pellicle. Thereof, the single profiles exhibit high inter-individual differences independent of their group affiliation, stating the initial pellicle to represent a rather "individual fingerprint". Quantitative analyses imply slight indication for 23 proteins potentially capable of counting for caries-specific biomarkers.

Conclusions And Clinical Relevance: The introduced protocol enables the individual analysis of minimal protein amounts and allows for highly precise characterizations and comparisons of individual proteomic profiles. The results contain a considerable higher extent of protein identifications and might serve as a base for future large scale analyzes to identify discrimination factors for the development of caries susceptibility tests.
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http://dx.doi.org/10.1002/prca.201800143DOI Listing
July 2019

Impact of oral astringent stimuli on surface charge and morphology of the protein-rich pellicle at the tooth-saliva interphase.

Colloids Surf B Biointerfaces 2019 Feb 16;174:451-458. Epub 2018 Nov 16.

Clinic of Operative Dentistry, Periodontology and Preventive Dentistry, University Hospital, Saarland University, Building 73, 66421 Homburg/Saar, Germany.

The proteinaceous pellicle layer, which develops upon contact with saliva on the surface of teeth, is important for the formation of oral biofilms and for the protection of teeth from abrasion and chemically induced erosion. Astringent food ingredients comprising polyphenols, cationic macromolecules, and multivalent metal salts are known to interact with the pellicle. However, astringent-induced changes in the physicochemical properties of the tooth-saliva interphase are not yet completely understood. Here we provide comprehensive insights into interfacial charging, ultrastructure, thickness, and surface roughness of the pellicles formed on the model substrates silicon oxide (SiO), Teflon AF, and hydroxyapatite, as well as on bovine enamel before and after incubation with the astringents epigallocatechin gallate, tannic acid, iron(III) salt, lysozyme, and chitosan. Quartz crystal microbalance with dissipation monitoring demonstrated viscous behavior of untreated pellicles formed in vitro on the different materials. Electrokinetic (streaming current) measurements revealed that cationic astringents reverse the charge of native pellicles, whereas polyphenols did not change the charge under physiological pH condition. In addition, transmission electron microscopy and atomic force microscopy showed a concentration-dependent increase in average film thickness and pellicle surface roughness as induced by astringents. These multifaceted alterations of the salivary pellicle may come along with an increase in roughness perceived on the teeth, which is part of the complex sensations of oral astringency.
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http://dx.doi.org/10.1016/j.colsurfb.2018.11.028DOI Listing
February 2019

Comparing oral health in patients with different levels of dental anxiety.

Head Face Med 2018 Nov 20;14(1):25. Epub 2018 Nov 20.

Technische Universität Dresden, Carl Gustav Carus Faculty of Medicine, Division of Psychological and Social Medicine and Developmental Neurosciences, Research Group Applied Medical Psychology and Medical Sociology, Fetscherstr 74, 01307, Dresden, Germany.

Background: Dental Anxiety is still today one of the most common fears and is therefore a great challenge for every dental practitioner. The aim of this study was to identify patients with dental anxiety using the Dental Anxiety Scale and comparing different levels of dental anxiety with oral health using DMF-T and DMF-S index.

Methods: This study questioned 1549 patients over the course of three years (2002-2005). DAS questionnaires were handed out before treatment and the state of oral health was evaluated using DMF-T and DMF-S.

Results: There is no significant relation between high anxiety and the global DMF-T Score (p = 0.237), missing teeth (p = 0.034) and filled teeth (p = 0.237). There is however a significant increase in destroyed teeth, the higher the level of dental anxiety in the patient (p < 0.0001). There is as well a significant relationship between the global DMF-S Score (p = 0.042) and dental anxiety. No relationship was found comparing missing surfaces (p = 0.107) and filled surfaces (p = 0.516) with dental anxiety. Destroyed 16 surfaces are, however, significantly higher in patients with more dental anxiety (p < 0.0001). A higher dental anxiety therefore often causes minimalistic dentistry to fail due to more teeth being destroyed.

Conclusions: Patients with dental anxiety still have a worse oral hygiene than patients without dental anxiety. It is still necessary, in this time of caries prevention rather than over-treatment, to be educated so that patients suffering dental fear receive the right treatment.
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http://dx.doi.org/10.1186/s13005-018-0182-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6247764PMC
November 2018

Comparison of initial oral microbiomes of young adults with and without cavitated dentin caries lesions using an in situ biofilm model.

Sci Rep 2018 09 18;8(1):14010. Epub 2018 Sep 18.

Policlinic of Operative and Pediatric Dentistry, Medical Faculty Carl Gustav Carus, TU Dresden, Dresden, Germany.

Dental caries is caused by acids released from bacterial biofilms. However, the in vivo formation of initial biofilms in relation to caries remains largely unexplored. The aim of this study was to compare the oral microbiome during the initial phase of bacterial colonization for individuals with (CC) and without (NC) cavitated dentin caries lesions. Bovine enamel slabs on acrylic splints were worn by the volunteers (CC: 14, NC: 13) for in situ biofilm formation (2 h, 4 h, 8 h, 1 ml saliva as reference). Sequencing of the V1/V2 regions of the 16S rRNA gene was performed (MiSeq). The relative abundances of individual operational taxonomic units (OTUs) were compared between samples from the CC group and the NC group. Random forests models were furthermore trained to separate the groups. While the overall heterogeneity did not differ substantially between CC and NC individuals, several individual OTUs were found to have significantly different relative abundances. For the 8 h samples, most of the significant OTUs showed higher relative abundances in the CC group, while the majority of significant OTUs in the saliva samples were more abundant in the NC group. Furthermore, using OTU signatures enabled a separation between both groups, with area-under-the-curve (AUC) values of ~0.8. In summary, the results suggest that initial oral biofilms provide the potential to differentiate between CC and NC individuals.
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http://dx.doi.org/10.1038/s41598-018-32361-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6143549PMC
September 2018

Application of optical and spectroscopic technologies for the characterization of carious lesions in vitro.

Biomed Tech (Berl) 2018 Oct;63(5):595-602

Technische Universität Dresden, Faculty of Medicine Carl Gustav Carus, Clinic of Operative and Pediatric Dentistry, Dresden, Germany.

The detection of the beginning demineralization process of dental hard tissue remains a challenging task in dentistry. As an alternative to bitewing radiographs, optical and spectroscopic technologies showed promising results for caries diagnosis. The aim of the present work is to give an overview of optical and spectroscopic properties of healthy and carious human teeth in vitro by means of Raman spectroscopy (RS), optical coherence tomography (OCT) and hyperspectral imaging (HSI). OCT was able to represent microstructural changes below the enamel surface and revealed increased scattering for white spot lesions and a white scattering trail for deeper lesions. HSI showed similar absorbance characteristics for healthy and demineralized enamel over the entire spectrum and a characteristic absorbance peak at 550 nm for discolored lesions. Already at early carious stages (white spot), we found a distinct loss of hydroxylapatite-related intensity at 959 cm-1 in demineralized regions with RS. Healthy and demineralized tooth surfaces can be distinguished at different signal levels by means of RS, OCT and HSI. The presented modalities provide additional information to the current clinical diagnosis of caries such as microstructural changes, quantification of the demineralization and imaging of caries-related chemical changes.
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http://dx.doi.org/10.1515/bmt-2017-0133DOI Listing
October 2018

Impact of the springtail's cuticle nanotopography on bioadhesion and biofilm formation and in the oral cavity.

R Soc Open Sci 2018 Jul 4;5(7):171742. Epub 2018 Jul 4.

Clinic of Operative Dentistry, Periodontology and Preventive Dentistry, University Hospital, Saarland University, Building 73, 66421 Homburg/Saar, Germany.

Springtails (Collembola) have a nanostructured cuticle. To evaluate and to understand anti-biofouling properties of springtail cuticles' morphology under different conditions, springtails, shed cuticles and cuticle replicates were studied after incubation with protein solutions and bacterial cultures using common models. In a second step, they were exposed to human oral environment in order to explore potential application in dentistry. , the cuticular structures were found to resist wetting by albumin solutions for up to 3 h and colonization by was inhibited. When exposed in the oral cavity, initial pellicle formation was of high heterogeneity: parts of the surface were coated by adsorbed proteins, others remained uncoated but exhibited locally attached, 'bridging', proteinaceous membranes spanning across cavities of the cuticle surface; this unique phenomenon was observed for the first time. Also the degree of bacterial colonization varied considerably. In conclusion, the springtail cuticle partially modulates bioadhesion in the oral cavity in a unique and specific manner, but it has no universal effect. Especially after longer exposure, the nanotextured surface of springtails is masked by the pellicle, resulting in subsequent bacterial colonization, and, thus, cannot effectively avoid bioadhesion in the oral cavity comprehensively. Nevertheless, the observed phenomena offer valuable information and new perspectives for the development of antifouling surfaces applicable in the oral cavity.
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http://dx.doi.org/10.1098/rsos.171742DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6083677PMC
July 2018

In vivo imaging in the oral cavity by endoscopic optical coherence tomography.

J Biomed Opt 2018 03;23(7):1-13

TU Dresden, Faculty of Medicine Carl Gustav Carus, Anesthesiology and Intensive Care Medicine, Clini, Germany.

The common way to diagnose hard and soft tissue irregularities in the oral cavity is initially the visual inspection by an experienced dentist followed by further medical examinations, such as radiological imaging and/or histopathological investigation. For the diagnosis of oral hard and soft tissues, the detection of early transformations is mostly hampered by poor visual access, low specificity of the diagnosis techniques, and/or limited feasibility of frequent screenings. Therefore, optical noninvasive diagnosis of oral tissue is promising to improve the accuracy of oral screening. Considering this demand, a rigid handheld endoscopic scanner was developed for optical coherence tomography (OCT). The novelty is the usage of a commercially near-infrared endoscope with fitting optics in combination with an established spectral-domain OCT system of our workgroup. By reaching a high spatial resolution, in vivo images of anterior and especially posterior dental and mucosal tissues were obtained from the oral cavity of two volunteers. The convincing image quality of the endoscopic OCT device is particularly obvious for the imaging of different regions of the human soft palate with highly scattering fibrous layer and capillary network within the lamina propria.
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http://dx.doi.org/10.1117/1.JBO.23.7.071207DOI Listing
March 2018

Identification of New Compounds from Sage Flowers (Salvia officinalis L.) as Markers for Quality Control and the Influence of the Manufacturing Technology on the Chemical Composition and Antibacterial Activity of Sage Flower Extracts.

J Agric Food Chem 2018 Feb 20;66(8):1843-1853. Epub 2018 Feb 20.

Clinic of Operative and Pediatric Dentistry, Medical Faculty Carl Gustav Carus, TU Dresden , Fetscherstr. 74, D-01307 Dresden, Germany.

Parts of Salvia species such as its flowers and leaves are currently used as a culinary herb and for some medicinal applications. To distinguish the different sage extracts it is necessary to analyze their individual chemical compositions. Their characteristic compounds might be established as markers to differentiate between sage flowers and leaf extracts or to determine the manufacturing technology and storage conditions. Tri-p-coumaroylspermidine can be detected only in flowers and has been described here for Salvia and Lavandula species for the first time. Markers for oxidation processes are the novel compounds salviquinone A and B, which were generated from carnosol by exposure to oxygen. Caffeic acid ethyl ester was established as an indirect marker for the usage of ethanol as extraction solvent. The compounds were identified by LC-QTOF-HRESIMS, LC-MS, NMR, IR, and single-crystal X-ray diffraction after isolation by semipreparative HPLC. Furthermore, sage flower resin showed interesting antibacterial in vitro activities against Gram-positive and Gram-negative bacteria.
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http://dx.doi.org/10.1021/acs.jafc.8b00581DOI Listing
February 2018

Accuracy and Usefulness of CBCT in Periodontology: A Systematic Review of the Literature.

Int J Periodontics Restorative Dent 2018 Mar/Apr;38(2):289-297

A systematic literature review was performed regarding the accuracy and usefulness of cone beam computed tomography (CBCT) in the field of periodontology. A total of 580 articles were identified, of which 13 met the inclusion criteria. Results showed a high accuracy of CBCT in visualizing periodontal structures and the demonstrated the usefulness of CBCT in regenerative periodontal surgery of maxillary molars. It remains questionable whether this gain of additional information actually leads to a better clinical outcome in periodontal treatment. Currently, the use of CBCT in periodontology should be restricted to complex periodontal cases, particularly those involving maxillary molars.
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http://dx.doi.org/10.11607/prd.2751DOI Listing
September 2018

Detection of carious lesions utilizing depolarization imaging by polarization sensitive optical coherence tomography.

J Biomed Opt 2018 01;23(7):1-8

Technische Universität Dresden, Faculty of Medicine Carl Gustav Carus, Anesthesiology and Intensive, Germany.

As dental caries is one of the most common diseases, the early and noninvasive detection of carious lesions plays an important role in public health care. Optical coherence tomography (OCT) with its ability of depth-resolved, high-resolution, noninvasive, fast imaging has been previously recognized as a promising tool in dentistry. Additionally, polarization sensitive imaging provides quantitative measures on the birefringent tissue properties and can be utilized for imaging dental tissue, especially enamel and dentin. By imaging three exemplary tooth samples ex vivo with proximal white spot, brown spot, and cavity, we show that the combination of polarization sensitive OCT and the degree of polarization uniformity (DOPU) algorithm is a promising approach for the detection of proximal carious lesions due to the depolarization contrast of demineralized tissue. Furthermore, we investigate different sizes of the DOPU evaluation kernel on the resulting contrast and conclude a suitable value for this application. We propose that DOPU provides an easy to interpret image representation and appropriate contrast for possible future screening applications in early caries diagnostics.
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http://dx.doi.org/10.1117/1.JBO.23.7.071203DOI Listing
January 2018

In vivo imaging of human oral hard and soft tissues by polarization-sensitive optical coherence tomography.

J Biomed Opt 2017 Dec;22(12):1-17

TU Dresden, Faculty of Medicine Carl Gustav Carus, Anesthesiology and Intensive Care Medicine, Clini, Germany.

Since optical coherence tomography (OCT) provides three-dimensional high-resolution images of biological tissue, the benefit of polarization contrast in the field of dentistry is highlighted in this study. Polarization-sensitive OCT (PS OCT) with phase-sensitive recording is used for imaging dental and mucosal tissues in the human oral cavity in vivo. An enhanced polarization contrast of oral structures is reached by analyzing the signals of the co- and crosspolarized channels of the swept source PS OCT system quantitatively with respect to reflectivity, retardation, optic axis orientation, and depolarization. The calculation of these polarization parameters enables a high tissue-specific contrast imaging for the detailed physical interpretation of human oral hard and soft tissues. For the proof-of-principle, imaging of composite restorations and mineralization defects at premolars as well as gingival, lingual, and labial oral mucosa was performed in vivo within the anterior oral cavity. The achieved contrast-enhanced results of the investigated human oral tissues by means of polarization-sensitive imaging are evaluated by the comparison with conventional intensity-based OCT.
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http://dx.doi.org/10.1117/1.JBO.22.12.121717DOI Listing
December 2017

Odontoblast-like differentiation and mineral formation of pulpsphere derived cells on human root canal dentin in vitro.

Head Face Med 2017 Dec 8;13(1):23. Epub 2017 Dec 8.

Clinic for Operative and Pediatric Dentistry, Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstraße 74, D-01307, Dresden, Germany.

Background: The revitalization or regeneration of the dental pulp is a preferable goal in current endodontic research. In this study, human dental pulp cell (DPC) spheres were applied to human root canal samples to evaluate their potential adoption for physiological tissue-like regeneration of the dental root canal by odontoblastic differentiation as well as cell-induced mineral formation.

Methods: DPC were cultivated into three-dimensional cell spheres and seeded on human root canal specimens. The evaluation of sphere formation, tissue-like behavior and differentiation as well as mineral formation of the cells was carried out with the aid of optical light microscopy, immunohistochemical staining and scanning electron microscopy (SEM).

Results: Spheres and cells migrated out of the spheres showed an intense cell-cell- and cell-dentin-contact with the formation of extra cellular matrix. In addition, the ingrowth of cell processes into dentinal tubules and the interaction of cell processes with the tubule walls were detected by SEM-imaging. Immunohistochemical staining of the odontoblast specific matrix proteins, dentin matrix protein-1, and dentin sialoprotein revealed an odontoblast-like cell differentiation in contact with the dentin surface. This differentiation was confirmed by SEM-imaging of cells with an odontoblast specific phenotype and cell induced mineral formation.

Conclusions: The results of the present study reveal the high potential of pulp cells organized in spheres for dental tissue engineering. The odontoblast-like differentiation and the cell induced mineral formation display the possibility of a complete or partial "dentinal filling" of the root canal and the opportunity to combine this method with other current strategies.
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http://dx.doi.org/10.1186/s13005-017-0156-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5723081PMC
December 2017

Initial microbial colonization of enamel in children with different levels of caries activity: An in situ study.

Am J Dent 2017 Jun;30(3):171-176

Clinic of Operative and Pediatric Dentistry Medical Faculty Carl Gustav Carus, Technical University Dresden, Germany.

Purpose: To investigate patterns of overnight in situ microbial colonization of enamel in children.

Methods: Overall, 29 children (aged 5-9 years) participated in the study. Nine were caries-free with no decayed, missing, or filled teeth (DMFT), 11 were caries-rehabilitated (DMFT ≥ 2, no active carious lesions), and nine were caries-active (DMFT ≥ 2, at least two carious lesions). Bovine enamel samples were fixed on individual upper jaw splints stored overnight in situ. 4',6-diamidino-2-phenylindole (DAPI) combined with Concanavalin A staining was applied for fluorescence microscopic visualization of total adherent bacteria and glucans. Fluorescence in situ hybridization (FISH) was used for distinction of eubacteria, streptococci, and Candida albicans. Salivary samples were investigated for Streptococcus mutans (S. mutans) by using CRT bacteria test and yeasts with Calcofluor white (CFW) staining.

Results: With all fluorescence methods, bacteria but not Candida albicans were detected on enamel samples. No statistically significant differences were observed in distribution patterns of the adherent bacteria between the groups. CFW staining indicated fungal structures in saliva samples of all participants. Based on CRT test results, the lowest amount of S. mutans were observed in caries-free children. Thus, initial microbial colonization patterns of enamel in children are not influenced by caries activity.

Clinical Significance: Caries activity in children may influence the process of initial bioadhesion and thus distribution patterns of bacterial attachment to the enamel surface. Investigation of in situ biofilm formation might provide valuable insights regarding the varying caries susceptibility in children.
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June 2017