Gain a Baby Lose a Tooth-Is There an Association between Periodontitis and Preterm Birth?

Preterm birth serves as one of the leading causes of neonatal mortality worldwide. The underlying mechanisms that contribute to preterm birth are not yet fully understood. However, an association between periodontitis and preterm birth has been proposed. The periodontal status and presence of periodontal pathogens in women with different birth outcomes have been previously examined. However, varying definitions of periodontitis and different microbiological methods make their interpretation challenging. The aim of this case-control study on women with and without preterm birth was to investigate their periodontal status using the current classification system for periodontal diseases. Moreover, differences in the periodontal microbiome of the study participants were investigated. Therefore, we collected data on oral and periodontal parameters in 77 puerperal women divided into two groups based on gestational age at delivery: 33 patients with preterm birth (PTB, <37 weeks) and 44 patients with term birth (TB, >37 weeks). These data included pocket probing depth (PPD), clinical attachment loss (CAL), bleeding on probing (BOP), gingival-bleeding index, DMFT index, and gynecologic and dental history. In addition, their oral microbiome was explored. Median CAL and percentage PPD ≥ 4 mm were significantly higher in the PTB group than in the TB group (p = 0.0128 and p = 0.047, respectively). Birth weight was significantly higher in periodontally healthy women than in those with gingivitis (p = 0.0078) or periodontitis (p = 0.0127). The periodontal microbiome differed significantly between groups. Our results are underlining the possible association between periodontitis and preterm delivery. Women with periodontitis had babies with significantly lower birth weights. The microbiome varied between the groups.

Phenotypic Adaptation to Antiseptics and Effects on Biofilm Formation Capacity and Antibiotic Resistance in Clinical Isolates of Early Colonizers in Dental Plaque.

Despite the wide-spread use of antiseptics in dental practice and oral care products, there is little public awareness of potential risks associated with antiseptic resistance and potentially concomitant cross-resistance. Therefore, the aim of this study was to investigate potential phenotypic adaptation in 177 clinical isolates of early colonizers of dental plaque (Streptococcus, Actinomyces, Rothia and Veillonella spp.) upon repeated exposure to subinhibitory concentrations of chlorhexidine digluconate (CHX) or cetylpyridinium chloride (CPC) over 10 passages using a modified microdilution method. Stability of phenotypic adaptation was re-evaluated after culture in antiseptic-free nutrient broth for 24 or 72 h. Strains showing 8-fold minimal inhibitory concentration (MIC)-increase were further examined regarding their biofilm formation capacity, phenotypic antibiotic resistance and presence of antibiotic resistance genes (ARGs). Eight-fold MIC-increases to CHX were detected in four Streptococcus isolates. These strains mostly exhibited significantly increased biofilm formation capacity compared to their respective wild-type strains. Phenotypic antibiotic resistance was detected to tetracycline and erythromycin, consistent with the detected ARGs. In conclusion, this study shows that clinical isolates of early colonizers of dental plaque can phenotypically adapt toward antiseptics such as CHX upon repeated exposure. The underlying mechanisms at genomic and transcriptomic levels need to be investigated in future studies.

A quantitative assessment of silicone and PTFE-based stamp techniques for restoring occlusal anatomy using resin-based composites.

OBJECTIVES: Publications on stamp techniques for placing resin-based composite (RBC) restorations consist mainly of case studies. Furthermore, comparative studies are rare and no longer relevant to the materials tested today. Thus, two general techniques were investigated in this study. MATERIALS AND METHODS: Standardized occlusion class I cavities were prepared in twenty-eight extracted caries-free wisdom teeth with unimpaired occlusal surfaces and restored with the RBC material Grandio®. Light curing of the final layer was performed either after removal of the stamp isolated with PTFE tape or by leaving a stamp made of transparent polysiloxane in place. CEREC scans of the RBC restorations placed (follow-up) were superimposed on scans of the unimpaired occlusal surface (baseline) and quantitatively analyzed with the software OraCheck with regard to volume change and gain or loss of layer thickness in six sectional planes. RESULTS: Assessing the excess material, there was no difference (p = 0.31) between the silicone technique (0.26 mm ± 0.02) and the PTFE technique (0.22 mm ± 0.02 mm). Nevertheless, the loss of tooth substance was significantly greater (p < 0.001) with the silicone technique (-0.29 mm ± 0.02 mm) than with the PTFE technique (-0.15 mm ± 0.02 mm). CONCLUSIONS: With the PTFE stamp technique, less healthy tooth structure was removed during the finishing procedure and the stamp was more dimensionally stable. CLINICAL RELEVANCE: The study shows the advantages and disadvantages of the investigated stamp techniques and helps the practitioner to choose an appropriate technique.

Analysis of the Influence of Jaw Periosteal Cells on Macrophages Phenotype Using an Innovative Horizontal Coculture System.

Jaw periosteum-derived mesenchymal stem cells (JPCs) represent a promising cell source for bone tissue engineering in oral and maxillofacial surgery due to their high osteogenic potential and good accessibility. Our previous work demonstrated that JPCs are able to regulate THP-1-derived macrophage polarization in a direct coculture model. In the present study, we used an innovative horizontal coculture system in order to understand the underlying paracrine effects of JPCs on macrophage phenotype polarization. Therefore, JPCs and THP-1-derived M1/M2 macrophages were cocultured in parallel chambers under the same conditions. After five days of horizontal coculture, flow cytometric, gene and protein expression analyses revealed inhibitory effects on costimulatory and proinflammatory molecules/factors as well as activating effects on anti-inflammatory factors in M1 macrophages, originating from multiple cytokines/chemokines released by untreated and osteogenically induced JPCs. A flow cytometric assessment of DNA synthesis reflected significantly decreased numbers of proliferating M1/M2 cells when cocultured with JPCs. In this study, we demonstrated that untreated and osteogenically induced JPCs are able to switch macrophage polarization from a classical M1 to an alternative M2-specific phenotype by paracrine secretion, and by inhibition of THP-1-derived M1/M2 macrophage proliferation.

How well can today's tooth-colored dental restorative materials reproduce the autofluorescence of human teeth? - Ambition and reality!

OBJECTIVES: The autofluorescence of dental hard tissues has been known for over 100 years. Thus, manufacturers add fluorophores to dental restorative materials to improve the esthetic properties of these materials. So far, there has been no study evaluating the ability of these fluorophores to reproduce the autofluorescence of dental hard tissues. MATERIALS AND METHODS: A total of 240 different color shades representing 17 different brands of fluorescent light-curing RBC and CAD/CAM restorative materials were analyzed with a monochromator-based microplate reader. Additionally, combined enamel-dentin specimens (n = 11) were analyzed as "gold standard". The total fluorescence (TF) and the physiologically relevant luminous efficiency function adjusted total fluorescence (TFa ) were determined. The differences between the brands and the enamel-dentin specimens were further evaluated and visualized as contour plots. RESULTS: Merely the TFa of the brands CERASMART™, Filtek Supreme XTE™, KZR-CAD HD 2, and LuxaCam composite were not significantly different to the enamel-dentin specimens. The analysis of the contour plots revealed that even these four materials showed a fluorescence excess for the excitation wavelengths below about 400 nm and a deficit above this wavelength. CONCLUSION: None of the materials analyzed in this study were able to reproduce the natural fluorescence spectrum of the enamel-dentin specimens. CLINICAL SIGNIFICANCE: Unlike the statements and images of blue fluorescent materials in the manufacturers' brochures, none of the materials examined here is fully capable of reproducing the natural autofluorescence of teeth.

Restorative CAD/CAM materials in dentistry: analysis of their fluorescence properties and the applicability of the fluorescence-aided identification technique (FIT).

OBJECTIVES: This study investigated the fluorescence properties of the most commonly used fluorescent CAD/CAM materials for monolithic dental restorations and their suitability to perform the fluorescence-aided identification technique (FIT). MATERIALS AND METHODS: A total of 175 different color shades (n = 1) from 13 CAD/CAM material brands were analyzed with a monochromator-based microplate reader. Additionally, dentin, enamel, and combined dentin-enamel specimens (respectively, n = 11) were analyzed for comparison purposes. The maximum fluorescence intensity, the corresponding excitation and emission wavelength, and the total fluorescence for the wavelength spectrum λex = 395 nm - 415 nm used for FIT were determined. RESULTS: All assessed CAD/CAM ceramics showed virtually no total fluorescence for the wavelength spectrum λex = 395 nm - 415 nm used for FIT. CERASMARTTM, KZR-CAD HD 2, and LuxaCam Composite displayed total fluorescence values similar to that of the tooth hard substances. All other resin-based CAD/CAM materials showed a significantly higher total fluorescence than the tooth hard substances. CONCLUSIONS: Apart from the mentioned exceptions, all CAD/CAM materials assessed could be suitable for the FIT, either because they are more fluorescent than hard tooth substances or because they do not fluoresce at all at the respective wavelength of λex = 395 nm - 415 nm. CLINICAL RELEVANCE: This study provides insight into the not yet well-known fluorescent properties of dental CAD/CAM materials. This knowledge is not only necessary to reproduce the fluorescence properties of natural teeth but also for the applicability of diagnostic fluorescence inducing techniques.

Minimally invasive removal of tooth-colored restorations: evaluation of a novel handpiece using the fluorescence-aided identification technique (FIT).

OBJECTIVES: This study investigated the ability of the fluorescence-aided identification technique (FIT) facilitated by a novel handpiece to simplify the removal of tooth-colored composite restorations with water-cooled rotating instruments. MATERIALS AND METHODS: Five undergraduate students and five dentists (6-14 years of professional experience) were asked to remove dental restorations in vitro using both the conventional technique (CT) and the fluorescence-aided identification technique. The FIT method was performed on teeth restored in addition to the fluorescent composite resin with the non-fluorescent (FIT1) and fluorescent (FIT2) bonding agent. CEREC scans were superimposed and three-dimensionally analyzed with the software OraCheck 2.13 with respect to the cavity surface area still covered with composite resin and the volume of the needlessly removed sound hard tissue. Additionally, the removal procedure was timed. RESULTS: The FIT2 group showed the most promising results: the smallest cavity surface area covered by composite resin independent of the professional expertise, and for the dentist group, the smallest amount of removed sound hard tissue and the fastest removal. CONCLUSIONS: Using the fiber optic of the handpiece for fluorescence excitation has been proven to be effective for performing the FIT, and therefore, to improve the removal of tooth-colored restorations. CLINICAL RELEVANCE: This study is basic research to encourage the integration of fluorescence inducing light sources in dental treatment units by the manufacturers as a prerequisite for a simplified daily use of the FIT.

Reprogramming of Urine-Derived Renal Epithelial Cells into iPSCs Using srRNA and Consecutive Differentiation into Beating Cardiomyocytes.

The generation of induced pluripotent stem cells (iPSCs) from patient's somatic cells and the subsequent differentiation into desired cell types opens up numerous possibilities in regenerative medicine and tissue engineering. Adult cardiomyocytes have limited self-renewal capacity; thus, the efficient, safe, and clinically applicable generation of autologous cardiomyocytes is of great interest for the treatment of damaged myocardium. In this study, footprint-free iPSCs were successfully generated from urine-derived renal epithelial cells through a single application of self-replicating RNA (srRNA). The expression of pluripotency markers and the in vitro as well as in vivo trilineage differentiation were demonstrated. Furthermore, the resulting iPSCs contained no residual srRNA, and the karyotyping analysis demonstrated no detectable anomalies. The cardiac differentiation of these iPSCs resulted in autologous contracting cardiomyocytes after 10 days. We anticipate that the use of urine as a non-invasive cell source to obtain patient cells and the use of srRNA for reprogramming into iPSCs will greatly improve the future production of clinically applicable cardiomyocytes and other cell types. This could allow the regeneration of tissues by generating sufficient quantities of autologous cells without the risk of immune rejection.

Improvement of Antibacterial Efficacy Through Synergistic Effect in Photodynamic Therapy Based on Thiazinium Chromophores Against Planktonic and Biofilm-Associated Periodontopathogens.

OBJECTIVE: Aim of the study was to improve the antibacterial efficacy of toluidine blue (TBO)/methylene blue (MB)-mediated photodynamic systems with light-emitting diode (LED) or laser irradiation administered to planktonic and biofilm-associated periodontopathogens. BACKGROUND DATA: Antibacterial photodynamic therapy (PDT) is a common, noninvasive adjunctive clinical method to inactivate microorganisms. So far, the disadvantage of this method has been its limited effectiveness in eliminating pathogens. METHODS: An anaerobic cocktail consisting of six representative periodontal pathogens was prepared as initial culture for planktonic samples and biofilms grown on human tooth slides. Both types of microbial samples were exposed to three commercial photodynamic systems (PDT1: TBO, 630 nm LED, PDT2: TBO, 635 nm laser, PDT3: MB, 665 nm laser) in conventional and a new modified approach (PDTplus) based on the use of an oxygen supplement (photosensitizer+hydrogen peroxide). The microbial viability was characterized by bacterial growth [colony forming units (CFU)], total bacterial cell counts, and microbial vitality. Statistical data analysis was performed using 95% confidence intervals (ANOVA) and post hoc Tukey's test (p < 0.05). RESULTS: The modified PDTplus showed the highest statistically significant synergistic antimicrobial activity for TBO-based systems evidenced by a CFU reduction of 9 log10 units to 0 for planktonic pathogens and a 4 log10 CFU reduction for biofilm bacteria. The MB-based PDTplus was superior mainly against biofilm pathogens. By comparison, the default TBO-based PDT achieved colony growth reductions of 2 and 1 log10 units concerning planktonic and biofilm cells. CONCLUSIONS: Compared to conventional PDT, PDTplus showed superior antibacterial efficacy based on its synergistic effect, promising vast application possibilities.

Metabolic activity of Streptococcus mutans biofilms and gene expression during exposure to xylitol and sucrose.

The objective of the study was to analyse Streptococcus mutans biofilms grown under different dietary conditions by using multifaceted methodological approaches to gain deeper insight into the cariogenic impact of carbohydrates. S. mutans biofilms were generated during a period of 24 h in the following media: Schaedler broth as a control medium containing endogenous glucose, Schaedler broth with an additional 5% sucrose, and Schaedler broth supplemented with 1% xylitol. The confocal laser scanning microscopy (CLSM)-based analyses of the microbial vitality, respiratory activity (5-cyano-2,3-ditolyl tetrazolium chloride, CTC) and production of extracellular polysaccharides (EPS) were performed separately in the inner, middle and outer biofilm layers. In addition to the microbiological sample testing, the glucose/sucrose consumption of the biofilm bacteria was quantified, and the expression of glucosyltransferases and other biofilm-associated genes was investigated. Xylitol exposure did not inhibit the viability of S. mutans biofilms, as monitored by the following experimental parameters: culture growth, vitality, CTC activity and EPS production. However, xylitol exposure caused a difference in gene expression compared to the control. GtfC was upregulated only in the presence of xylitol. Under xylitol exposure, gtfB was upregulated by a factor of 6, while under sucrose exposure, it was upregulated by a factor of three. Compared with glucose and xylitol, sucrose increased cell vitality in all biofilm layers. In all nutrient media, the intrinsic glucose was almost completely consumed by the cells of the S. mutans biofilm within 24 h. After 24 h of biofilm formation, the multiparametric measurements showed that xylitol in the presence of glucose caused predominantly genotypic differences but did not induce metabolic differences compared to the control. Thus, the availability of dietary carbohydrates in either a pure or combined form seems to affect the cariogenic potential of S. mutans biofilms.

Apical constriction: location and dimensions in molars-a micro-computed tomography study.

INTRODUCTION: The existence of the apical constriction has been repeatedly questioned. The aim of the present study was to validate the existence of the apical constriction and determine its location and dimensions in molars by using substantial micro-computed tomography analysis. METHODS: Ninety human molars with 271 canals were evaluated. Teeth with resorption, defects, or incomplete root formation as well as wisdom teeth were excluded. Patients' age was categorized into 3 groups. Teeth were scanned by micro-computed tomography with a resolution of 27 µm. Multi-threshold segmentation was performed to trace the canal outline in a total of 25,093 sections. In each cross section, 88 parameters, eg, area, circumference, and maximum and minimum diameter were recorded and analyzed. The apical constriction (AC) was defined to be the narrowest area extending along a distance of 0.1 mm or more at the apex. Size and form of the constriction were recorded as well as the distance to the apical foramen (AC-AF) and apex (AC-A). RESULTS: The mean distance of AC-AF was 0.2 mm (99% confidence interval, 0.15-0.24; range, 0-0.6 mm), and of AC-A it was 0.9 mm (99% confidence interval, 0.86-1.0; range, 0.1-1.7 mm). The type of canal had no influence on AC-AF and AC-A. In 76% of all canals the apical constriction was parallel. The mean size of constriction in molars was instrument size 30. Patients aged 30 or younger had significantly wider constrictions. CONCLUSIONS: The apical constriction was found to be located at or close to the foramen. The most common form was the parallel form.

Dynamic Production of Soluble Extracellular Polysaccharides by Streptococcus mutans.

Caries development in the presence of Streptococcus mutans is associated not only with the production of extracellular water-insoluble polymers but also is based on water-soluble polysaccharides. The aim of this study was the evaluation of a novel glucan-specific Lectin assay for monitoring water-soluble EPS produced by S. mutans during several growth periods in different media. S. mutans cultures were grown for 24 h, 48 h, and 144 h in medium deficient of sucrose (A) and medium supplemented with 5% sucrose (B). Microtiter well plates were coated with cell-free supernatants followed by the addition of labeled Concanavalin-A and enzyme substrate. The substrate reactions were kinetically detected at 405 nm. The validation of the assay was performed using carbohydrates dextran, xanthan, and sucrose as reference. This new Concanavalin-A-based assay showed the highest sensitivity for dextran and revealed that the glucan production of S. mutans reached its maximum at 144 h in medium B according to bacterial maturation.

Neurosensory impairment of the mental nerve as a sequel of periapical periodontitis: case report and review.

Apical periodontitis of endodontic origin rarely leads to sensory impairment of the inferior alveolar or mental nerve. This article reviews and documents a clinical case of neurological disorder where paresthesia and hypesthesia of the mental nerve resulted as a sequel of apical periodontitis of a mandibular second premolar. The healing process and long-term results 3 years after conventional root canal treatment are presented.

Real-time microsensor measurement of local metabolic activities in ex vivo dental biofilms exposed to sucrose and treated with chlorhexidine.

Dental biofilms are characterized by structural and functional heterogeneity. Due to bacterial metabolism, gradients develop and diverse ecological microniches exist. The aims of this study were (i) to determine the metabolic activity of microorganisms in naturally grown dental biofilms ex vivo by measuring dissolved oxygen (DO) and pH profiles with microelectrodes with high spatial resolution and (ii) to analyze the impact of an antimicrobial chlorhexidine (CHX) treatment on microbial physiology during stimulation by sucrose in real time. Biofilms were cultivated on standardized human enamel surfaces in vivo. DO and pH profiles were measured in a flow cell system in sterile human saliva, after sucrose addition (10%), again after alternative treatment of the sucrose exposed biofilms with CHX (0.2%) for 1 or 10 min or after being killed with paraformaldehyde (4%). Biofilm structure was visualized by vitality staining with confocal microscopy. With saliva as the sole nutrient source oxygen consumption was high within the superficial biofilm layers rendering deeper layers (>220 mum) anoxic. Sucrose addition induced the thickness of the anaerobic zone to increase with a concurrent decrease in pH (7.1 to 4.4). CHX exposure reduced metabolic activity and microbial viability at the biofilm surface and drove metabolic activity deeper into the biofilm. CHX treatment led to a reduced viability at the biofilm surface with minor influence on overall biofilm physiology after 1 min; even after 10 min there was measurable respiration and fermentation inside the biofilm. However, the local microenvironment was more aerated, less acidogenic, and presumably less pathogenic.

Consistency of apex locator function: a clinical study.

The consistency of apex locators was determined by calculating the dysfunction frequency. Electronic working length (EWL) was determined in 507 patients requiring endodontic treatment. Different clinical parameters were recorded including tooth vitality, presence of obliteration, and metallic restoration. Two apex locators were used (Root ZX [Morita, Tokyo, Japan] and Raypex5 [VDW, Munich, Germany]). Apex locator performance was considered "consistent" when the scale bars were stable and moved only in correspondence to the movement of file in the root canal. A working length radiograph with files set to the EWL was performed. EWL were considered "acceptable" when the file tip was located 0 to 2 mm short of the radiographic apex. The function of apex locators was consistent in 85% of the patients (429/507 [99% confidence interval, 80-88]). The inconsistent measurements were strongly associated with partially or totally obliterated root canals (p < 0.0001). Radiographically, 97% of consistent measurements were "acceptable."

Biofilm plaque and hydrodynamic effects on mass transfer, fluoride delivery and caries.

BACKGROUND: The biofilm concept of dental plaque now is widely accepted in the dental clinic, particularly with respect to its importance to oral hygiene. A number of reviews have focused on the microbial ecology of biofilm with regard to oral health; however, there has been less focus on how the interaction of biofilms and hydrodynamics with mass transfer (the movement of molecules and particulates) and physiological processes may relate to caries. TYPES OF STUDIES REVIEWED: The authors reviewed reports in the microbiology and dental literature addressing microbiological, engineering and clinical aspects of biofilms with respect to mass transport and microbial physiology, with an emphasis on fluoride ions (F(-)). CONCLUSIONS: and Practical Implications. These data illustrate how dental plaque biofilms may affect the delivery of cariogenic agents, such as sucrose, or anticariogenic agents, such as F(-), into and out of the biofilm, with subsequent consequences for the development of physio-chemical microenvironments at the tooth surface. Increasing the flow rate in an overlying fluid (such as saliva or mouthrinse) increases transport from the fluid into and through biofilms. Increasing the delivery of anticariogenic agents such as F(-) into the plaque biofilm, by generating strong fluid flows, may be a useful strategy for enhancing the anticaries effects of F(-) in areas of the mouth where complete biofilm removal is not possible with routine daily cleaning techniques.

Effect of xylitol/chlorhexidine versus xylitol or chlorhexidine as single rinses on initial biofilm formation of cariogenic streptococci.

OBJECTIVES: Oral bacteria implying a natural resistance may deteriorate the antibacterial efficacy of chlorhexidine on cariogenic microorganisms. Xylitol, mostly applied via chewing gum, is known to possess favorable plaque-reducing properties. The aim of this study was to investigate the effect of a xylitol rinse formulated as pure solution or combined with chlorhexidine on the viability of Streptococcus sanguis (early colonizer of human teeth) and Streptococcus mutans (the most causal strain for caries) during initial steps of biofilm formation. METHOD AND MATERIALS: After exposure to the test solutions, the bacteria suspended in human sterile saliva were allowed to attach to human enamel slides for 60 minutes in a preclinical flow chamber system. The bacterial vitality of suspended and attached cells was monitored using 2 fluorescent DNA stains by epifluorescence microscopy. Further parameters measured were the total bacterial cell counts on enamel slides and growth of suspended streptococci. RESULTS: The sensitivity of S mutans to pure chlorhexidine or in combination with xylitol is contrary to the natural resistance of S sanguis to chlorhexidine. The combination of xylitol/chlorhexidine showed a statistically significant antivital effect on S sanguis cells compared to the pure agents xylitol and chlorhexidine. The bacterial cell density on enamel and bacterial reproduction on agar plates were similarly affected by the combination of xylitol/chlorhexidine or the single substances. CONCLUSION: The newly discovered synergistic antivital effect of xylitol combined with chlorhexidine may contribute to the favorable potential of xylitol use for the improvement of new formulations of caries-preventive mouthrinses.

Adhesion of Streptococcus sanguinis to dental implant and restorative materials in vitro.

Bacterial adhesion to tooth surfaces or dental materials starts immediately upon exposure to the oral environment. The aim of this study, therefore, was to compare the adhesion of Streptococcus sanguinis to saliva-coated human enamel and dental materials - during a one-hour period - using an in vitro flow chamber system which mimicked the oral cavity. After fluorescent staining, the number of adhered cells and their vitality were recorded. The dental materials used were: titanium (Rematitan M), gold (Neocast 3), ceramic (Vita Omega 900), and composite (Tetric Ceram). The number of adherent bacterial cells was higher on titanium, gold, and ceramic surfaces and lower on composite as compared to enamel. As for the percentage of adherent vital cells, it was higher on enamel than on the restorative materials tested. These results suggested that variations in the number and vitality of the adherent pioneer oral bacteria, S. sanguinis, in the in vitro system depended on the surface characteristics of the substratum and the acquired salivary pellicle. The in vitro adhesion model used herein provided a simple and reproducible approach to investigate the impact of surface-modified dental materials on bacterial adhesion and vitality.