Development of an Inflammation-Triggered In Vitro "Leaky Gut" Model Using Caco-2/HT29-MTX-E12 Combined with Macrophage-like THP-1 Cells or Primary Human-Derived Macrophages.

The "leaky gut" syndrome describes a damaged (leaky) intestinal mucosa and is considered a serious contributor to numerous chronic diseases. Chronic inflammatory bowel diseases (IBD) are particularly associated with the "leaky gut" syndrome, but also allergies, autoimmune diseases or neurological disorders. We developed a complex in vitro inflammation-triggered triple-culture model using 21-day-differentiated human intestinal Caco-2 epithelial cells and HT29-MTX-E12 mucus-producing goblet cells (90:10 ratio) in close contact with differentiated human macrophage-like THP-1 cells or primary monocyte-derived macrophages from human peripheral blood. Upon an inflammatory stimulus, the characteristics of a "leaky gut" became evident: a significant loss of intestinal cell integrity in terms of decreased transepithelial/transendothelial electrical resistance (TEER), as well as a loss of tight junction proteins. The cell permeability for FITC-dextran 4 kDa was then increased, and key pro-inflammatory cytokines, including TNF-alpha and IL-6, were substantially released. Whereas in the M1 macrophage-like THP-1 co-culture model, we could not detect the release of IL-23, which plays a crucial regulatory role in IBD, this cytokine was clearly detected when using primary human M1 macrophages instead. In conclusion, we provide an advanced human in vitro model that could be useful for screening and evaluating therapeutic drugs for IBD treatment, including potential IL-23 inhibitors.

Inductively Coupled Intraoral Flexible Coil for Increased Visibility of Dental Root Canals in Magnetic Resonance Imaging.

OBJECTIVES: Accurate visualization of dental root canals is vital for the correct diagnosis and subsequent treatment. This work assesses the improvement of a dedicated new coil for dental magnetic resonance imaging (MRI) in comparison to conventional ones in terms of signal-to-noise ratio (SNR) and visibility. MATERIALS AND METHODS: A newly developed intraoral flexible coil was used to display dental roots with MRI, and it provides improved sensitivity with a loop design and size adjusted to a single tooth anatomy. Ex vivo and in vivo measurements were performed on a 3 T clinical MR system, and results were compared with conventional head and surface coil images. Additional comparison was performed with a modified fast spin echo sequence and a constructive interference in steady-state sequence. RESULTS: Ex vivo, an SNR gain of 6.3 could be achieved with the intraoral flexible coil setup, and higher visibility down to 200 µm was possible, whereas the external loop coil is limited to 400 µm. In vivo measurements in a volunteer resulted in an SNR gain of up to 4.5 with an improved delineation of the root canals, especially for the branch tissue splitting of the mesial root canal into mesial-buccal and mesial-lingual. CONCLUSIONS: In summary, we showed the feasibility of implementing a wireless coil approach with readily available dental practice materials for sealing and placement. Highly improved MRI scans can be acquired within clinically feasible scan times, and this might provide additional medical findings to supplement available x-ray images.

Long-Term Fluctuation of Oral Biofilm Microbiota following Different Dietary Phases.

Caries development is associated with shifts in the oral biofilm microbiota and primarily linked to frequent simple carbohydrate consumption. Different nutritional ingredients can either promote or prevent caries development. To investigate the effects of selected ingredients on the oral biofilm microbiota in situ, 11 study participants underwent 3-month-long dietary phases with intake of a regular diet (PI), additional frequent sucrose (PII), milk and yoghurt (PIII), and a diet rich in dietary fiber (PIV) and then returned to their regular diet (PV). Oral biofilm was sampled and analyzed applying 16S rRNA Illumina MiSeq sequencing. Additionally, the effect on the enamel was analyzed by measuring enamel surface roughness with laser scanning microscopy. The beta-diversity results showed that the microbiota in all the following phases differed significantly from PI and that the microbial community in PII was significantly different from all other phases. The abundance of the genus Streptococcus fluctuated over the course of the five phases, with a significant increase in PII (P = 0.01), decreasing in PIII and PIV (PIII and PIV versus PII: P < 0.00001) and increasing again toward PV. Other taxa showed various fluctuations of their abundances, with PV returning approximately to the levels of PI. In conclusion, while elevated sucrose consumption favored caries-promoting non-mutans streptococci, frequent milk and yoghurt intake caused a significant decrease in the abundance of these microbial taxa and in addition reduced enamel surface roughness. These results indicate that modulations of the oral biofilm microbiota can be attained even in adults through dietary changes and corresponding recommendations can be made for the prevention of caries development.IMPORTANCE Caries affects a large proportion of the population worldwide, resulting in high treatment costs. Its etiology can be ascribed to shifts of the microbiota in dental biofilms primarily driven by dietary factors. It is unclear how diet affects the microbial community of plaque biofilm in situ and whether it can be modulated to help prevent caries development. To address these issues, we analyzed changes of the in situ plaque microbiota following 3-month-long dietary changes involving elevated sucrose, dairy, and dietary fiber consumption over a period of 15 months. Applying high-throughput sequencing, we found non-mutans streptococci, a taxonomic group involved in the beginning stages toward microbial dysbiosis, in decreased abundance with elevated dairy and dietary fiber intake. Through analysis of the enamel surface roughness, these effects were confirmed. Therefore, correspondent dietary measures can be recommended for children as well as adults for caries prevention.

Accuracy of CBCT-based root canal length predetermination using new endodontic planning software compared to measurements performed with an electronic apex locator ex vivo.

OBJECTIVE: To evaluate the accuracy of the new endodontic planning software (3D Endo Dentsply Sirona) based on cone beam computed tomography (CBCT) to predetermine root canal lengths compared with measurements performed with an electronic apex locator (Raypex 6; VDW) ex vivo. MATERIALS AND METHODS: CBCT scans of forty extracted human maxillary (n = 20) and mandibular (n = 20) molars were taken, and root canal lengths were predetermined with the 3D Endo software using the apical foramen (AF) and the adjoining cusp as references. Root canal lengths were determined with the Raypex 6 using the same references. To evaluate the accuracy, absolute differences between both methods and the actual root canal length (gold standard) were calculated and statistically analyzed. RESULTS: Differences between lengths measured with the 3D Endo and the Raypex 6 compared with the gold standard showed no significant differences (P = 0.879). Mean differences were 0.37 mm versus 0.35 mm in the maxillary molars, and 0.30 mm versus 0.31 mm in the mandibular molars. A total of 75.8% (3D Endo) and 79.1% (Raypex 6) of all measurements were within the limits of ± 0.5 mm. Both methods showed a tendency to result in short measurements (P < 0.001). CONCLUSIONS: Within the limitations of this study, the 3D Endo software enables an accurate three-dimensional (3D) predetermination of root canal lengths.

In-vivo shift of the microbiota in oral biofilm in response to frequent sucrose consumption.

Caries is associated with shifts of microbiota in dental biofilms and primarily driven by frequent sucrose consumption. Data on environmentally induced in vivo microbiota shifts are scarce therefore we investigated the influence of frequent sucrose consumption on the oral biofilm. Splint systems containing enamel slabs were worn for 3 × 7 days with 7-day intervals to obtain oral biofilm samples. After a three-month dietary change of sucking 10 g of sucrose per day in addition to the regular diet, biofilm was obtained again at the end of the second phase. The microbiota was analysed using Illumina MiSeq amplicon sequencing (v1-v2 region). In addition, roughness of the enamel surface was measured with laser scanning microscopy. The sucrose phase resulted in significant differences in beta-diversity and significantly decreased species richness. It was marked by a significant increase in abundance of streptococci, specifically Streptococcus gordonii, Streptococcus parasanguinis and Streptococcus sanguinis. Enamel surface roughness began to increase, reflecting initial impairment of dental enamel surface. The results showed that frequent sucrose consumption provoked compositional changes in the microbiota, leading to an increase of non-mutans streptococci, hence supporting the extended ecological plaque hypothesis and emphasizing the synergy of multiple bacterial species in the development of caries.

Effect of 10% fluoride on the remineralization of dentin in situ

ABSTRACT Objective The purpose of this randomized, cross-over, in situ study was to determine the remineralization of demineralized dentin specimens after the application of a 10% fluoride (F-) or a 1% chlorhexidine–1% thymol (CHX–thymol) varnish. Material and Methods Twelve individuals without current caries activity wore removable appliances in the lower jaw for a period of four weeks. Each appliance contained four human demineralized dentin specimens fixed on the buccal aspects. The dentin specimens were obtained from the cervical regions of extracted human third molars. After demineralization, half the surface of each specimen was covered with a nail varnish to serve as the reference surface. The dentin specimens were randomly assigned to one of the three groups: F-, CHX–thymol, and control (no treatment). Before the first treatment period and between the others, there were washout periods of one week. After each treatment phase, the changes in mineral content (vol% µm) and the lesion depths (µm) of the dentin slabs were determined by transverse microradiography (TMR). Data analysis was accomplished by the Kruskal-Wallis test and the Mann-Whitney U test (p<0.05). Results The medians (25th/75th percentile) of integrated mineral loss were 312.70 (203.0-628.7) for chlorhexidine varnish, 309.5 (109.8-665.8) for fluoride varnish, and -346.9 (-128.7 - -596.0) for the control group. The medians (25th/75th percentile) of lesion depth were 13.6 (5.7-34.5) for chlorhexidine varnish, 16.5 (5.6-38.1) for fluoride varnish, and -14.2 (-4.5- -32.9) for the control group. Use of the 10% F- or 1% CHX–1% thymol varnishes resulted in significantly decreased mineral loss and lesion depth in dentin when compared with the control group. There were no statistically significant differences among the test groups. Conclusions Within the limitations of this study, the results suggest that the effect of the treatment of demineralized dentin with 10% F- or 1% CHX–1% thymol is better than without any treatment.

Effect of 10% fluoride on the remineralization of dentin in situ.

Objective The purpose of this randomized, cross-over, in situ study was to determine the remineralization of demineralized dentin specimens after the application of a 10% fluoride (F-) or a 1% chlorhexidine-1% thymol (CHX-thymol) varnish. Material and Methods Twelve individuals without current caries activity wore removable appliances in the lower jaw for a period of four weeks. Each appliance contained four human demineralized dentin specimens fixed on the buccal aspects. The dentin specimens were obtained from the cervical regions of extracted human third molars. After demineralization, half the surface of each specimen was covered with a nail varnish to serve as the reference surface. The dentin specimens were randomly assigned to one of the three groups: F-, CHX-thymol, and control (no treatment). Before the first treatment period and between the others, there were washout periods of one week. After each treatment phase, the changes in mineral content (vol% µm) and the lesion depths (µm) of the dentin slabs were determined by transverse microradiography (TMR). Data analysis was accomplished by the Kruskal-Wallis test and the Mann-Whitney U test (p<0.05). Results The medians (25th/75th percentile) of integrated mineral loss were 312.70 (203.0-628.7) for chlorhexidine varnish, 309.5 (109.8-665.8) for fluoride varnish, and -346.9 (-128.7 - -596.0) for the control group. The medians (25th/75th percentile) of lesion depth were 13.6 (5.7-34.5) for chlorhexidine varnish, 16.5 (5.6-38.1) for fluoride varnish, and -14.2 (-4.5- -32.9) for the control group. Use of the 10% F- or 1% CHX-1% thymol varnishes resulted in significantly decreased mineral loss and lesion depth in dentin when compared with the control group. There were no statistically significant differences among the test groups. Conclusions Within the limitations of this study, the results suggest that the effect of the treatment of demineralized dentin with 10% F- or 1% CHX-1% thymol is better than without any treatment.

The use of computer-assisted FACE for minimal-invasive caries excavation.

OBJECTIVES: Caries excavation is still a demanding procedure today. In the past years, methods using light-induced fluorescence have proven their ability to detect bacteria remaining in the tooth's hard tissues. However, methods to control the complete removal of infected dentine have not yet been validated. The aim of the present study was to evaluate the degree of dentine removal during caries excavation using a camera- and software-based device as a guide for fluorescence-aided caries excavation (FACE) in comparison to visual-tactile inspection and a dye-staining method. MATERIALS AND METHODS: One hundred teeth with carious lesions (C3) were randomly allocated to four groups and excavated with the respective method as primary excavation control method. When the first method indicated complete caries excavation, a second method was used to affirm this. Subsequently, dentine samples were taken to determine residual contamination using PCR. After embedding and sectioning the teeth dentine, microhardness was measured perpendicular to the cavity floor. RESULTS: By using the camera- and software-based device, 94 % of the cavities tested were free of bacterial contamination. All cavities excavated with the dye-staining or visual-tactile control method were free of bacterial contamination but resulted in a significantly higher dentine removal. CONCLUSION: The camera- and software-assisted caries excavation seems to be an adequate method to remove contaminated dentine without removing affected dentine. CLINICAL RELEVANCE: Beside its original application to monitor carious, the device is safe, effective, and easy to use for guided caries excavation and is of worth for both everyday practice and undergraduate education.

Action of food preservatives on 14-days dental biofilm formation, biofilm vitality and biofilm-derived enamel demineralisation in situ.

AIMS: The aims of this double-blind, controlled, crossover study were to assess the influence of food preservatives on in situ dental biofilm growth and vitality, and to evaluate their influence on the ability of dental biofilm to demineralize underlying enamel over a period of 14 days. MATERIALS AND METHODS: Twenty volunteers wore appliances with six specimens each of bovine enamel to build up intra-oral biofilms. During four test cycles of 14 days, the subjects had to place the appliance in one of the assigned controls or active solutions twice a day for a minute: negative control 0.9 % saline, 0.1 % benzoate (BA), 0.1 % sorbate (SA) and 0.2 % chlorhexidine (CHX positive control). After 14 days, the biofilms on two of the slabs were stained to visualize vital and dead bacteria to assess biofilm thickness (BT) and bacterial vitality (BV). Further, slabs were taken to determine mineral loss (ML), by quantitative light-induced laser fluorescence (QLF) and transversal microradiography (TMR), moreover the lesion depths (LD). RESULTS: Nineteen subjects completed all test cycles. Use of SA, BA and CHX resulted in a significantly reduced BV compared to NaCl (p < 0.001). Only CHX exerted a statistically significant retardation in BT as compared to saline. Differences between SA and BA were not significant (p > 0.05) for both parameters. TMR analysis revealed the highest LD values in the NaCl group (43.6 ± 44.2 µm) and the lowest with CHX (11.7 ± 39.4 µm), while SA (22.9 ± 45.2 µm) and BA (21.4 ± 38.5 µm) lay in between. Similarly for ML, the highest mean values of 128.1 ± 207.3 vol% µm were assessed for NaCl, the lowest for CHX (-16.8 ± 284.2 vol% µm), while SA and BA led to values of 83.2 ± 150.9 and 98.4 ± 191.2 vol% µm, respectively. With QLF for both controls, NaCl (-33.8 ± 101.3 mm(2) %) and CHX (-16.9 ± 69.9 mm(2) %), negative values were recorded reflecting a diminution of fluorescence, while positive values were found with SA (33.9 ± 158.2 mm(2) %) and BA (24.8 ± 118.0 mm(2) %) depicting a fluorescence gain. These differences were non-significant (p > 0.05). CONCLUSION: The biofilm model permited the assessment of undisturbed oral biofilm formation influenced by antibacterial components under clinical conditions for a period of 14 days. An effect of BA and SA on the demineralization of enamel could be demonstrated by TMR and QLF, but these new findings have to be seen as a trend. As part of our daily diet, these preservatives exert an impact on the metabolism of the dental biofilm, and therefore may even influence demineralization processes of the underlying dental enamel in situ.

Teaching model for artificial teeth and endodontic apex locators.

Artificial teeth are a useful teaching aid during endodontic education. This article describes the development of a simple and inexpensive model that can be equipped with artificial teeth. It shows that working length determination in artificial root canals using electronic apex locators is possible and that the embedding media has no influence on measurements. The model supports the application of current endodontic techniques and facilitates a validated evaluation of the treatments between students. Artificial teeth can be removed for visualization and replaced for further endodontic exercises.

Efficacy of tooth bleaching with and without light activation and its effect on the pulp temperature: an in vitro study.

The aim of this in vitro study was to evaluate the colour stability of bleaching after light activation with halogen unit, laser, LED unit or chemical activation up to 3 months after treatment. Four groups of teeth (n = 20) were bleached with Opalescence Xtra Boost (38% hydrogen peroxide) using four different methods: activation with halogen, LED, laser or chemical activation only. All teeth were bleached in one session for four times (4 × 15 min) and the colour was evaluated using a spectrophotometer at the following time points: before bleaching, immediately after bleaching, 1 day, and 1 and 3 months after the end of bleaching. Between the tested time points, the teeth were stored in 0.9% NaCl solution. Additionally, the temperature increase in the pulp chamber was measured using a measuring sensor connected to a computer. Bleaching with the halogen unit showed the highest colour change. Halogen unit, laser and chemical activation resulted in whiter teeth after 1 and 3 months compared to the colour after the end of the bleaching procedure (p ≤ 0.05). Three months after the end of bleaching, the shade changes observed were-halogen: 7.1 > chemical activation: 6.2 > LED: 5.4 > laser: 5.2. Halogen showed the highest temperature increase (17.39°C ± 1.96) followed by laser (14.06°C ± 2.55) and LED (0.41°C ± 0.66) (p < 0.0001). Chemical activation did not affect the temperature in the pulp chamber. The use of light activation did not show any advantages compared to chemical bleaching. Although halogen unit showed the higher shade's change, its use resulted also in the higher pulp temperature. According to the present findings, light activation of the bleaching agent seems not to be beneficial compared to bleaching without light activation, concerning the colour stability up to 3 months after bleaching and the pulp temperature caused during the bleaching procedure.

Release of monomers from four different composite materials after halogen and LED curing.

PURPOSE: To evaluate the release of monomers from four different composite materials (Ceram X, Filtek Supreme XT, Tetric Flow, Tetric EvoCeram), polymerized using either halogen or LED unit. METHODS: Ten specimens were made for each material/unit combination. Each specimen was stored in 1 ml 75% ethanol. The storage medium was renewed after 1, 7 and 28 days. Aliquots of this medium were analyzed by LC-MS/MS. RESULTS: The effect of the curing unit on monomers' release differed significantly among the materials (P < 0.0001). The amount of BisGMA and TEGDMA released from Ceram X was not influenced by the unit used (P > 0.05). Curing with LED reduced the amount of Bisphenol A released from Ceram X compared to halogen. For Filtek Supreme XT, the type of unit exerted a significant effect on the elution of BisGMA (P < or = 0.05). LED curing resulted in a higher release of TEGDMA and UDMA compared to halogen (P < or = 0.05). For Tetric Flow, LED curing resulted in lower monomer release (P < 0.0001). For Tetric EvoCeram, the amounts of BisGMA, UDMA and Bisphenol A were higher when polymerizing with LED compared to halogen. The release of substances was more material dependent and less influenced by the curing unit used.

The effect of cervical preflaring using different rotary nickel-titanium systems on the accuracy of apical file size determination.

INTRODUCTION: An exact determination of the apical root canal diameter is crucial for correct cleaning and shaping of a root canal. The aim of this study was to investigate the discrepancies of the initial apical root canal diameter and the diameter that is measured by the initial apical file (IAF) after cervical flaring using current rotary nickel-titanium systems. METHODS: Mesiobuccal canals of 40 extracted mandibular molars were randomly assigned to four groups. In the first group, root canals were not flared. Root canals of the other groups were preflared using FlexMaster (VDW, Munich, Germany), ProTaper (Dentsply, Konstanz, Germany), or RaCe (FKG Dentaire, Genf, Switzerland) instruments. The tooth length was determined by inserting an ISO 06 K-file to the apical foramen. The working length (WL) was set 1 mm short of the apical foramen. File sizes were increased after binding sensation was felt at the WL. Transversal sections of the WL regions were examined under stereomicroscope, and the diameter of the root canal and the IAF at WL were assessed. RESULTS: Canals preflared with RaCe instruments had the lowest discrepancy between the apical root canal diameter and the IAF diameter (15.7 ± 9.7 µm) followed by ProTaper (22.2 ± 11.0 µm) and FlexMaster (35.0 ± 17.2 µm). CONCLUSIONS: Preflaring of root canals prevents underestimation of the actual apical root canal diameter. The type of instruments used for preflaring show differences on the accuracy of IAF determination. Preflaring with larger tapered instruments leads to a more accurate apical sizing, and this information is crucial concerning the appropriate final diameter for complete apical shaping.

The evaluation of fluorescence changes after application of casein phosphopeptides (CPP) and amorphous calcium phosphate (ACP) on early carious lesions.

PURPOSE: To evaluate the effect of casein phosphopeptides (CPP) and amorphous calcium phosphate (ACP), as an adjunct to average oral hygiene, on the fluorescence of initial carious fissures and pits in vivo. METHODS: For this investigator-blind in vivo study 32 volunteers were recruited. Subjects with premolars and molars showing DIAGNOdent-values between 15 and 20 were randomly assigned to two treatment groups. During a wash-out period of 2 weeks and during the 3-week treatment period all subjects were instructed to use only standard fluoride toothpaste (1450 ppm F- as NaF) and to abstain from any oral hygiene products other than dental tape. During the treatment period, one group additionally applied a CPP-ACP containing cream on the respective fissures for 3 minutes, once per day. At Days 1, 8, 15, and 22, DIAGNOdent measurements and a visual assessment of the fissures were performed by two calibrated independent examiners. RESULTS: No significant changes of DIAGNOdent values were found in the control group during the study period. Fissures additionally treated with the CPP-ACP containing cream showed significantly lower laser fluorescence values after Day 15 (P = 0.001) and Day 22 (P < 0.001) compared to the control group. No significant difference in the visual classification between the two groups could be found.

Apical quality and adaptation of Resilon, EndoREZ, and Guttaflow root canal fillings in combination with a noncompaction technique.

The objective of this study was to compare the quality of Guttaflow (Coltene/Whaledent, Langenau, Germany), Resilon/Epiphany (Jeneric/Pentron, Kusterdingen, Germany), and EndoREZ (Ultradent Products, Inc, South Jordan, UT) root canal fillings. Thirty single-rooted teeth were randomly assigned to three groups: Resilon/Epiphany, EndoREZ, and Guttaflow. After radiography of the root canal fillings, the roots were sectioned horizontally at the level of 2 mm and 4 mm from the apex. The area of voids and adaptation to canal walls and points were evaluated using light microscopy and calculated through a computer program. The radiographs showed no significant differences between the materials (p > 0.05, Mann-Whitney U test). Evaluation of cross-sections revealed sealer adaptation >99% to the root canals and >98% to the points. Resilon/Epiphany had significantly higher values at 98.8% (standard deviation [SD] = 3.9%) than EndoREZ at 98.7% (SD = 1.1%), and Guttaflow at 98.5 (SD = 2.1%) (p < 0.05, Mann-Whitney U test). The absolute difference compared with Resilon/Epiphany was at 0.84% (0.44%-1.76%) for EndoREZ and at 1.08% for Guttaflow (0.00%-2.08%) (95% confidence interval, Hodges-Lehman). This outcome indicated an effective apical obturation using any of the three materials in combination with a noncompaction technique.

Effect of dentifrice containing 5000 ppm fluoride on non-cavitated fissure carious lesions in vivo after 2 weeks.

PURPOSE: This randomized clinical trial compared the ability of two dentifrices, one containing 5000 ppm fluoride (Duraphat) and the other 1450 ppm fluoride (Caries Protection, control) to reverse non-cavitated fissure carious lesions. METHODS: 30 adults having occlusal lesions with DIAGNOdent values between 10 and 20 were randomly assigned to two groups of 15 participants each. DIAGNOdent measurements were performed after cleaning the teeth with cleaning brushes and after additional cleaning using an airflow device. The participants were instructed to brush their teeth three times a day for 3 minutes after the meals with a 2 cm line of their assigned dentifrice. After a period of 2 weeks, the teeth were cleaned again with the airflow device and laser fluorescence measurement was performed. RESULTS: The group using the dentifrice containing 5000 ppm showed a significantly higher decrease in laser fluorescence (21%) over the test period than the control group (4%; P< 0.001; repeated measures ANOVA). The decrease in laser fluorescence in the test group was significant (P< 0.001; Wilcoxon signed-rank test). The difference between cleaning the teeth with cleaning brushes and additional cleaning with airflow before DIAGNOdent measurement was not statistically different (P> 0.05; Wilcoxon signed-rank test).

Effect of adhesive resin cements and post surface silanization on the bond strengths of adhesively inserted fiber posts.

This study evaluated the tensile bond strengths and the effect of silanization of fiber posts inserted with different adhesive systems. Sixty DT Light Posts (size 1) were used. Thirty posts were pretreated with silane. The posts were cemented into form-congruent artificial root canals (12 mm) of bovine dentine. Six groups were formed: G1, Prime&Bond NT/Calibra; G2, Monobond-S+Prime&Bond NT/Calibra; G3, ED Primer/Panavia 21ex; G4, Monobond-S+ED Primer/Panavia 21ex; G5, RelyX Unicem; and G6, Monobond-S+RelyX Unicem. The mean (standard deviation) tensile bond strengths (megapascals) were 7.69 (0.85) for G1, 7.15 (1.01) for G2, 6.73 (0.85) for G3, 6.78 (0.97) for G4, 4.79 (0.58) for G5, and 4.74 (0.88) for G6. G1 achieved significantly higher bond strengths than G3 and G5; G3 had significantly higher values than G5 (P < .05; Scheffé procedure). Silanization had no significant effect (P > .05, one-way analysis of variance). Tensile bond strengths were significantly influenced by the type of resin cement. Silanization of fiber post surfaces seems to have no clinical relevance.

Two-year clinical evaluation of Cerec 3D ceramic inlays inserted by undergraduate dental students.

OBJECTIVE: To evaluate the clinical results of final-year dental students' clinical performance after a practical computer-based course and training in the new Cerec 3 method. METHOD AND MATERIALS: Cerec 3D restorations (Sirona) were made and inserted in patients by 50 dental students. The students were in their final semester in the Department of Operative Dentistry. Before treatment of the patients began, the students had undergone computer-based Cerec 3D training. The training included lessons comprising the whole Cerec procedure from planning to insertion of the restoration. Vital permanent premolars or molars requiring a 2- or 3-surface restoration were selected for the study. The evaluation started 1 week after luting. The inlays were examined in accordance with the US Public Health Service (USPHS) criteria at baseline and after 6, 12, and 24 months. RESULTS: The 2-year survival rate of the restorations was estimated to be 93.3% according to Kaplan-Meier. No statistically significant changes were observed in color match, surface texture, and anatomic form. The decrease of pulpal hypersensitivity during the observation period was statistically significant (P <.05). CONCLUSION: Dental students are capable of delivering demanding clinical tasks after appropriate training. The introduction of CAD/CAM restorations to the dental curriculum resulted in high short-term success rates. Further investigations are required to evaluate the long-term success of those restorations. To achieve a clinically adequate performance, it is necessary to consider the basic rules and technology associated with ceramic restorations.

Influence of adhesive systems on bond strength between fiber posts and composite resin cores in a pull-out test design.

The aim of this study was to evaluate the effects of post surface conditioning with adhesive systems on tensile bond strength between two composite resin core systems and FRP posts (ER DentinPost). Forty-eight posts were trimmed at the coronal part, and the upper part of 3 mm was covered with a standardized composite resin core build-up. Twenty-four posts were treated with the respective adhesive systems. Four groups were formed: G1 - ClearfilCore; G2 - Clearfil New Bond + ClearfilCore; G3 - MultiCore Flow; and G4 - AdheSE + MultiCore Flow. Mean (SD) bond strengths in MPa were 7.53 (0.89) for ClearfilCore and 8.08 (0.93) for New Bond + ClearfilCore; 5.80 (0.39) for MultiCore Flow and 5.92 (0.43) for AdheSE + MultiCore Flow. ClearfilCore achieved significantly higher bond strengths than MultiCore Flow (two-way ANOVA; p<0.0001). In conclusion, composite resin core materials exerted a significant influence on tensile bond strength, while adhesive systems did not significantly affect the results.

Remineralization of artificial interproximal carious lesions using a fluoride mouthrinse.

PURPOSE: To evaluate remineralization and fluoride uptake of demineralized enamel specimens in artificial interproximal spaces using a 250 ppm fluoride mouthrinse (100 ppm amine fluoride and 150 ppm sodium fluoride) compared to a placebo-mouthrinse. METHODS: This was a two-way, double-blind, in situ study. 24 volunteers wore intraoral appliances in the lower jaw with mounted demineralized enamel specimens forming an artificial interproximal space. The volunteers rinsed their mouths for 28 days, twice a day with the respective mouthrinse and brushed their teeth at least twice a day with a fluoride-free dentifrice. The specimens were cleaned once a day to simulate the use of dental floss. For analysis methods transversal microradiography, fluoride content measurement and quantitative light-induced fluorescence were used. RESULTS: Mineral gain was significantly higher after the use of the fluoride mouthrinse: 571.88 Vol.% x microm (+/- 79.33 Vol.% x microm SEM) compared to the placebo treatment 51.14 Vol.% x microm (+/- 72.14 Vol.% x microm SEM). Significantly more fluoride uptake was observed after using the fluoride mouthrinse: 3666.39 microg/cm3 (+/- 513.50 microg/cm3 SEM) than after the placebo mouthrinse: 516.95 microg/cm3 (+/- 75.83 microg/cm3 SEM). The quantitative light-induced fluorescence showed a significant remineralizing effect after the fluoride treatment: -388.47 % x mm2 (+/- 18.76% x mm2 SEM) compared to the placebo treatment -27.88% x mm2 (+/- 20.19% x mm2 SEM).