Effect of Cleft Lip on Adolescent Evaluation of Faces: An Eye-Tracking Study.

PURPOSE: Adolescence is a delicate phase during life in which self-stigmatization increases and acceptance by peers becomes more important. However, little is known about how adolescents with cleft lip and/or palate experience this stage of life. Therefore, the purpose of this study was to investigate how cleft lip and/or palate (CLP) adolescents are looked at by their peers and how they look at others with/without CLP. METHODS: In this prospective, cross-sectional study 54 observers (CLP versus control) performed an eye-tracking task and gave attractiveness/ valence ratings. For this purpose, they were shown pictures of patients with and without CLP with neutral or smiling facial expressions. RESULTS: Adolescents with CLP were looked at differently compared to their unaffected peers, with shorter fixations of the eyes and longer fixations of the nose and mouth. Smiling altered the scan path toward the mouth for all faces. Contrary to the control group, adolescents with CLP tended to spend less time fixating the eyes. In the attractiveness/valence ratings, CLP adolescents were rated more negatively. CONCLUSIONS: Adolescents with cleft lip and/or palate look differently at peers and are also viewed with an alternate scan path.

Donor variation and sex hormone receptors in periodontal ligament cells.

OBJECTIVE: This study evaluated the gene expression and protein synthesis of sex hormone receptors in human periodontal ligament cells (PDLCs) in relation to donor- and tooth-specific factors with the aim to clarify the debate about sex hormone receptors in PDLCs. DESIGN: The expression patterns of estrogen receptors (genes: ESR1 and ESR2; proteins: ERα and ERß), androgen receptor (AR) and progesterone receptor (PR) were investigated in the context of immortalization status, previous orthodontic tooth movement (OTM), donor age, sex and hormonal stimulation in PDLCs from 14 healthy donors (male: n = 8, female: n = 6; adolescents: n = 8, adults: n = 6) using quantitative real-time polymerase chain reaction, Western blot and immunocytochemistry. RESULTS: For ERß, the full-length isoform ERß1 and truncated variants were detected. For ERα, the expected isoform ERα66 was not observed, but a novel isoform ERα36 was detected. Immortalization status, previous OTM and donor age had no impact on ESR1 and ESR2 expression. Estradiol stimulation for 24 h doubled the ratio of ESR2/ESR1 in PDLCs from female but not male donors, indicating sex-specific patterns of receptor expression. AR and PR demonstrated insufficient protein synthesis in PDLCs. CONCLUSIONS: The data revealed a pivotal role for and complex interplay between ERα and ERß in human PDLCs regardless of variable donor characteristics. Therefore, PDLC biology might be altered in patients of each age group and both sexes due to hormonal changes. This should be kept in mind during periodontic and orthodontic treatment of patients with special hormonal status.

The Influence of TGF-ß3, EGF, and BGN on SOX9 and RUNX2 Expression in Human Chondrogenic Progenitor Cells.

Osteoarthritis (OA) is the most common chronic joint disease and leads to the degradation of the extracellular matrix by an imbalance between anabolic and catabolic processes. TGF-ß3 (transforming growth factor beta-3) and epidermal growth factor (EGF) influence the osteochondrogenic potential of chondrocytes. In this study, we compared the expression of mediators and receptors in the TGF-ß3 and EGF pathways, as well as biglycan (BGN), in healthy and diseased chondrocytes. Furthermore, we used chondrogenic progenitor cells (CPCs) for in vitro stimulation and knockdown experiments to elucidate the effects of TGF-ß3 and EGF on the chondrogenic potential. Our results demonstrate that the expression of TGF-beta receptor type-1 (TGFBRI) and epidermal growth factor receptor (EGFR) is altered in diseased chondrocytes as well as in CPCs. Moreover, TGF-ß3 and EGF stimulation influenced the expression levels of BGN, SRY (sex determining region Y)-box 9 (SOX9), and Runt-related transcription factor 2 (RUNX2) in CPCs. Therefore, changes in TGFBRI and EGFR expression likely contribute to the degenerative and regenerative effects seen in late stages of OA.

Perception of children with visible untreated and treated caries.

OBJECTIVES: This study aimed to analyse if children with untreated or treated caries (restorations/missing teeth) are perceived differently compared to children with healthy teeth and to explore possible differences in the perception by laypersons and dental experts. METHODS: Eye movements of female experts (n = 20) and laypersons (n = 18) were recorded by eye-tracking while paired images (neutral expression/teeth not visible; emotional expression/smiling, teeth visible) of children with healthy teeth, with visible untreated or treated caries (restorations/missing teeth as a consequence of caries treatment), each n = 13, were presented. First fixation, total fixation time and number of fixations on the areas of interest (eyes, nose, mouth) in the first two seconds of presentation were determined. Furthermore, the images were rated regarding arousal, valence and attractivity. Statistical analysis was performed using Mann-Whitney-U- and Kruskal-Wallis-tests (α = 0.05). RESULTS: Generally, laypersons spent more time exploring and fixating the eye region than the mouth, while dental experts more often first percept and longer and more often fixated the mouth region, especially in images with emotional expression. Dental experts, but not laypersons, were significantly longer fixating the mouth of children with untreated caries than the mouth of children with healthy teeth in images with emotional expression. When evaluating images with emotional expression, both dental experts and laypersons rated children with healthy teeth to be more attractive, pleasant and calm than children with untreated or treated caries. CONCLUSIONS: Children with visible treated and untreated caries were differently perceived by laypersons and dental experts than children with healthy teeth.

A new albumin-depletion strategy improves proteomic research of gingival crevicular fluid from periodontitis patients.

OBJECTIVES: Gingival crevicular fluid (GCF), the inflammatory infiltrate within the crevicular sulcus, is of great importance for diverse processes in the oral cavity and has a high impact in oral sciences. It is assumed to serve as a source of biomarkers for systemic or periodontal diseases and mediators of orthodontic tooth movement. In order to characterize the protein content of the GCF in an unbiased and complete approach, we employed mass spectrometry (MS), which allows not only the identification, but also the quantification of these proteins. In samples obtained from patients suffering from periodontitis, this method is often limited due to the presence of highly abundant serum albumin deriving from serum. The aim of this investigation was to employ a protein precipitation procedure for the efficient depletion of serum albumin from GCF samples. MATERIALS AND METHODS: GFC samples collected from five adult periodontitis patients were fractionated by trichloroacetic acid/acetone precipitation and the resulting soluble and pelleted fractions were analyzed by SDS-PAGE and high-resolution mass spectrometry. RESULTS: Trichloroacetic acid/acetone precipitation was successfully employed as a protein precipitation procedure for the efficient depletion of serum albumin from GCF samples. Careful analysis revealed that the precipitation step reduced the serum albumin content efficiently, and increased subsequent protein identifications by 32%. Three hundred seventeen proteins could only be identified with this new approach. CONCLUSION: The increased coverage of the GCF proteome will help improve our understanding of molecular mechanisms in the periodontium during pathogenesis of periodontitis. CLINICAL RELEVANCE: Our new albumin depletion strategy combined with high-resolution mass spectrometry can be used to effectively monitor the molecular signals of the periodontium.

Valid gene expression normalization by RT-qPCR in studies on hPDL fibroblasts with focus on orthodontic tooth movement and periodontitis.

Meaningful, reliable and valid mRNA expression analyses by real-time quantitative PCR (RT-qPCR) can only be achieved, if suitable reference genes are chosen for normalization and if appropriate RT-qPCR quality standards are met. Human periodontal ligament (hPDL) fibroblasts play a major mediating role in orthodontic tooth movement and periodontitis. Despite corresponding in-vitro gene expression studies being a focus of interest for many years, no information is available for hPDL fibroblasts on suitable reference genes, which are generally used in RT-qPCR experiments to normalize variability between samples. The aim of this study was to identify and validate suitable reference genes for normalization in untreated hPDL fibroblasts as well as experiments on orthodontic tooth movement or periodontitis (Aggregatibacter actinomycetemcomitans). We investigated the suitability of 13 candidate reference genes using four different algorithms (geNorm, NormFinder, comparative ΔCq and BestKeeper) and ranked them according to their expression stability. Overall PPIB (peptidylprolyl isomerase A), TBP (TATA-box-binding protein) and RPL22 (ribosomal protein 22) were found to be most stably expressed with two genes in conjunction sufficient for reliable normalization. This study provides an accurate tool for quantitative gene expression analysis in hPDL fibroblasts according to the MIQE guidelines and shows that reference gene reliability is treatment-specific.

Removable thermoplastic appliances modified by incisal cuts show altered biomechanical properties during tipping of a maxillary central incisor.

BACKGROUND: The present study aimed to evaluate the force delivery of removable thermoplastic appliances (RTAs), modified by different sized incisal cuts, during tipping of a maxillary central incisor in palatal and vestibular direction. METHODS: Forty-five RTAs from three different materials (Biolon®, Erkodur®, Ideal Clear®) of the same thickness (1 mm) were used. Analysis was performed on a separated maxillary central incisor which was part of a resin model with a complete dentition. In 15 RTAs, of different material, a cut was inserted at the incisal edge of tooth 11. In 15 other appliances, the cut was extended to teeth 12 and 21. Fifteen aligners remained uncut. The experimental tooth was tipped starting from the zero position in 0.05° steps to a maximal deflection of ± 0.42° of the incisal edge in vestibular and palatal direction, after positioning the RTA onto the model. RESULTS: The horizontal (Fx) and the vertical (Fz) force components were decreased by approximately half with increasing cut size. Fz values changed during palatal tipping from a weak intrusive force, for aligners without cut, to an extrusive force with increasing cut size. Compared to both other materials used (Erkodur® and Ideal Clear®), the Biolon® aligners showed significantly higher Fx and Fz values (p < 0.0001, respectively). CONCLUSIONS: RTAs modified by different sized incisal cuts show altered biomechanical properties and an inversion of the vertical force component, during tipping of a maxillary central incisor.

Mapping the secretome of human chondrogenic progenitor cells with mass spectrometry.

Tissue engineering offers promising perspectives in the therapy of osteoarthritis. In the context of cell-based therapy, chondrogenic progenitor cells (CPCs) may be used to regenerate defects in cartilage tissue. An in-depth characterization of the secretome of CPCs is a prerequisite to this approach. In this study, a method was developed for the qualitative and quantitative analysis of the secretome of undifferentiated and differentiated CPCs. Secreted proteins from cells grown in two-dimensional as well as three-dimensional alginate cultures were extracted and analyzed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Quantitation was achieved by internal standardization using stable isotope-labeled amino acids in cell culture (SILAC). Qualitative analysis of CPC secretomes revealed ECM-components, signal proteins and growth factors most of which were also found in healthy cartilage. A quantitative comparison revealed significantly upregulated proteins with regenerative potential during differentiation, while proteins involved in catabolic metabolism were significantly downregulated. The development of methods for qualitative and quantitative analysis of the secretome of CPCs by mass spectrometry provides a foundation for the investigation of progenitor or stem cells from other sources.