Tooth-composite bond failure with a universal and an etch-and-rinse adhesive depending on mode and frequency of application.

OBJECTIVES: To evaluate the effect of an additional layer of universal adhesive on the interfacial enamel/dentin-composite gap formation in relation to application mode and aging, via spectral domain optical coherence tomography (SD-OCT) and scanning electron microscopy (SEM). METHODS: In vitro class V cavities in 114 caries-free premolars were restored by applying one or two layers of a universal adhesive (Scotchbond Universal, SBU) in self-etch (se) and etch-and-rinse (er) mode or the reference adhesive OptiBond FL (OFL-er). The restorations were imaged by SD-OCT (six groups, n = 8) and SEM (n = 3) directly after filling (t1), water storage (t2, 24 h), embedding (t3), and thermo-mechanical loading (t4, TCML). The interfacial gaps were quantified using 26 parameters and analyzed using principal component analysis and linear mixed effect models. RESULTS: Gap formation at enamel and dentin was significantly influenced by the adhesive, the application mode and number of layers (p < 0.001). This was due to the influence of the SBU-er mode (p < 1e-05), which showed significantly more gap formation and a greater range of variation with double application when compared to SBU-se and OFL. The fewest interfacial gaps occurred with one or two applications of OFL-er and one layer of SBU-er. SIGNIFICANCE: Adhesive application mode and the number of adhesive layers are relevant factors in the tooth-composite bond failure. Double application worsened the adaptation of SBU to freshly prepared dentin conditioned with phosphoric acid.

Characterization of baseline hemodynamics after the Fontan procedure: a retrospective cohort study on the comparison of 4D Flow MRI and computational fluid dynamics.

Introduction: The aim of this study was to characterize the hemodynamics of Fontan patients using both four-dimensional flow magnetic resonance imaging (4D Flow MRI) and computational fluid dynamics (CFD). Methods: Twenty-nine patients (3.5 ± 0.5 years) who had undergone the Fontan procedure were enrolled, and the superior vena cava (SVC), left pulmonary artery (LPA), right pulmonary artery (RPA), and conduit were segmented based on 4D Flow MRI images. Velocity fields from 4D Flow MRI were used as boundary conditions for CFD simulations. Hemodynamic parameters such as peak velocity (Vmax), pulmonary flow distribution (PFD), kinetic energy (KE), and viscous dissipation (VD) were estimated and compared between the two modalities. Results and discussion: The Vmax, KE, VD, PFDTotal to LPA, and PFDTotal to RPA of the Fontan circulation were 0.61 ± 0.18 m/s, 0.15 ± 0.04 mJ, 0.14 ± 0.04 mW, 41.3 ± 15.7%, and 58.7 ± 15.7% from 4D Flow MRI; and 0.42 ± 0.20 m/s, 0.12 ± 0.05 mJ, 0.59 ± 0.30 mW, 40.2 ± 16.4%, and 59.8 ± 16.4% from CFD, respectively. The overall velocity field, KE, and PFD from the SVC were in agreement between modalities. However, PFD from the conduit and VD showed a large discrepancy between 4D Flow MRI and CFD, most likely due to spatial resolution and data noise. This study highlights the necessity for careful consideration when analyzing hemodynamic data from different modalities in Fontan patients.

Metabolomic Profiling of Citrus unshiu during Different Stages of Fruit Development.

Citrus fruits undergo significant metabolic profile changes during their development process. However, limited information is available on the changes in the metabolites of Citrus unshiu during fruit development. Here, we analyzed the total phenolic content (TPC), total carotenoid content (TCC), antioxidant activity, and metabolite profiles in C. unshiu fruit flesh during different stages of fruit development and evaluated their correlations. The TPC and antioxidant activity significantly decreased during fruit development, whereas the TCC increased. The metabolite profiles, including sugars, acidic compounds, amino acids, flavonoids, limonoids, carotenoids, and volatile compounds (mono- and sesquiterpenes), in C. unshiu fruit flesh also changed significantly, and a citrus metabolomic pathway related to fruit development was proposed. Based on the data, C. unshiu fruit development was classified into three groups: Group 1 (Aug. 1), Group 2 (Aug. 31 and Sep. 14), and Group 3 (Oct. 15 and Nov. 16). Although citrus peel was not analyzed and the sensory and functional qualities during fruit development were not investigated, the results of this study will help in our understanding of the changes in chemical profile during citrus fruit development. This can provide vital information for various applications in the C. unshiu industry.

OCT Evaluation of Marginal and Internal Interface Integrity of Class V Composite Restorations after 36 to 48 Months.

PURPOSE: To compare a self-etch and a two-step etch-and-rinse adhesive in terms of internal and marginal composite-tooth bond failure separately on enamel and dentin/cement at 36-48 months after restoration placement using optical coherence tomography (OCT). MATERIALS AND METHODS: Twenty-seven patients with two or three class V composite restorations of noncarious cervical lesions 36-48 months after placement were included. The one-step self-etch adhesive Futurabond M ([Voco] group SE, n = 25) and the two-step etch-and-rinse adhesive Solobond M ([Voco] group ER, n = 20) combined with the nanohybrid composite Amaris (Voco) were evaluated. The four-step etch-and-rinse adhesive Syntac classic combined with Tetric EvoCeram (Ivoclar Vivadent) served as the control (n = 18). Spectral-domain OCT (SD-OCT, 1310-nm center wavelength) was applied. Marginal gaps and internal interfacial adhesive defects were quantified in cross-sectional OCT images. Groups were statistically compared using the Friedman/Wilcoxon test (α = 0.05). RESULTS: In enamel, nonsignificantly different percentages of marginal gap formation and internal interfacial adhesive defects were found between the groups (pi ≥ 0.258). In dentin/cement, SE showed significantly less marginal gap formation compared to ER (p < 0.001) and control (p = 0.001), and at the internal dentin-composite interface less adhesive defects were found compared to ER (p < 0.001) and control (p = 0.003). CONCLUSION: The self-etch adhesive used in the current study appears recommendable for restoration of noncarious cervical lesions with composite.

Clinical and OCT assessment of application modes of a universal adhesive in a 12-month RCT.

OBJECTIVES: To evaluate a universal adhesive clinically using FDI criteria and by optical coherence tomography (OCT). METHODS: In 50 patients, three or four non-carious cervical lesions (NCCL) were restored with composite (Venus® Diamond Flow, Kulzer) using iBond® Universal (iBU, Kulzer) applied in self-etch (iBU-SE, n = 50), selective-enamel-etch (iBU-SEE, n = 29) or etch-and-rinse mode (iBU-ER, n = 50) and the reference OptiBond™ FL (OFL, Kerr, n = 50). Restorations were imaged by SD-OCT. The weighted mean length of interfacial adhesive defects (AD, %) was quantified per restoration immediately after placement (t0), simultaneously with clinical assessment (FDI criteria) after 14 days (t1), 6 (t2) and 12 months (t3). Data were statistically analyzed (McNemar-/Wilcoxon-/Mann-Whitney-U test (α = 0.05), Kaplan-Meier survival curves). RESULTS: After 12 months, cumulative failure rates were lower with iBU-SE (0.0%; p = 0.016), iBU-SEE (0.0%; p = 0.125), and iBU-ER (2.1%; p = 0.070; loss t3) compared to OFL (16.7%; losses t2, t3). Generally, marginal adaptation decreased (pi < 0.001) and marginal staining increased (pi ≤ 0.031), without significant group differences (pi > 0.064). AD increased in all groups (pi < 0.001). At enamel, AD appeared more extended with iBU-SE vs. iBU-SEE (t2-t3; pi ≤ 0.005), iBU-ER (t1-t3; pi ≤ 0.051) and OFL (t0-t3; pi ≤ 0.018). At dentin/cement iBU generally caused fewer defects than OFL (t1-t3; pi ≤ 0.010) and with SE vs. ER (t2-t3; pi = 0.010). CONCLUSIONS: In NCCLs, iBU generally provides a more durable bond than OFL. Recommended mode is SEE. Clinic and OCT provided comparable results. OCT has higher statistical power, shows group differences earlier and specifically for the different hard tooth tissues. CLINICAL SIGNIFICANCE: The universal adhesive iBU was superior against the reference OFL in NCCLs. It can be recommended with SEE. Evaluation of interfacial adhesive defects by OCT seems to allow early prediction of adhesives' clinical performance.

Arrest of root caries with an adjuvant chlorhexidine-fluoride varnish over a 12-months observation period: a QLF-analyzed, placebo-controlled, randomized, clinical trial (RCT).

This study aimed at evaluating the effectiveness of an adjuvant chlorhexidine-fluoride varnish (Cervitec F) for prevention and arrest of root caries on elderly participants using quantitative light-induced fluorescence (QLF). 23 participants with two or three non-cavitated root carious lesions were included and assigned to three groups of different varnishes (CF: Cervitec F, P: placebo, DP: Duraphate). Agents were applied once to root surface at baseline and in follow-up after 3, 6 and 9 months. The lesions were assessed clinically and with QLF. QLF-images were analyzed regarding fluorescence loss (ΔF), lesion volume (ΔQ) and bacterial activity (ΔR) before (t0), after 14 days (t1), 6- (t2) and 12-months (t3). CF showed a significant difference between t0 and t3: ∆F (- 12.51 [15.41] vs. - 7.80 [16.72], p = 0.012), ∆Q (- 2339.97 (20,898.30) vs. - 751.82 (5725.35), p < 0.001), ∆R (23.80 [41.70] vs. 7.07 [37.50], p = 0.006). Independently of the varnish application, preventive care seems positively influence the root caries progress. Although within CF group the strongest effect was observed, no superiority of a specific varnish application was confirmed over a 12-months QLF observation period. Extra topical fluoride can help remineralise dentin lesions and QLF can be used as a measurement method to determine changes in the dentin lesions.

Evaluation of quantitative light-induced fluorescence to assess lesion depth in cavitated and non-cavitated root caries lesions - An in vitro study.

BACKGROUND: This in vitro study aimed to assess carious lesions on root surfaces using quantitative light-induced fluorescence (QLF) and to compare the readings with axial lesion depth on µCT. METHODS: The root surfaces of 107 extracted human teeth were included after visual-tactile inspection. For further analysis, the following parameters were assessed: clinical findings (non-cavitated: leathery or hard, cavitated), QLF- (QLF-D Biluminator 2+), and µCT-images (Bruker Skyscan 1172). The shape of the undamaged tooth surface of the cavitated lesions was virtually re-constructed during µCT analysis. Clinical surface texture,% fluorescence loss, and lesion depth (µCT) were determined. STATISTICAL ANALYSIS: chi²-test, Spearman-Rho test, regression analysis. RESULTS: ∆F was significantly lower in non-cavitated leathery (-50.37 ± 15.10) and cavitated (-61.23 ± 9.92) compared to non-cavitated surfaces with a hard texture (-17.04 ± 16.10, p < 0.01). For non-cavitated surfaces, a negative correlation was observed between ∆F and lesion depth in µCT images regardless of texture (-0.748, p < 0.01). Regression analysis revealed that ∆F predicted lesion depth in µCT for non-cavitated surfaces (ß: 0.703, CI95: 0.67--0.43, p < 0.01). CONCLUSION: The percentage of fluorescence loss (∆F) in QLF predicted lesion depth of non-cavitated demineralized root surfaces. Therefore, QLF can be recommended for estimating the lesion depth of carious root lesions and seems to expand the possibilities of follow-up and lesion monitoring, especially for non-cavitated surfaces.

In-vitro and In-Vivo Assessment of 4D Flow MRI Reynolds Stress Mapping for Pulsatile Blood Flow.

Imaging hemodynamics play an important role in the diagnosis of abnormal blood flow due to vascular and valvular diseases as well as in monitoring the recovery of normal blood flow after surgical or interventional treatment. Recently, characterization of turbulent blood flow using 4D flow magnetic resonance imaging (MRI) has been demonstrated by utilizing the changes in signal magnitude depending on intravoxel spin distribution. The imaging sequence was extended with a six-directional icosahedral (ICOSA6) flow-encoding to characterize all elements of the Reynolds stress tensor (RST) in turbulent blood flow. In the present study, we aimed to demonstrate the feasibility of full RST analysis using ICOSA6 4D flow MRI under physiological conditions. First, the turbulence analysis was performed through in vitro experiments with a physiological pulsatile flow condition. Second, a total of 12 normal subjects and one patient with severe aortic stenosis were analyzed using the same sequence. The in-vitro study showed that total turbulent kinetic energy (TKE) was less affected by the signal-to-noise ratio (SNR), however, maximum principal turbulence shear stress (MPTSS) and total turbulence production (TP) had a noise-induced bias. Smaller degree of the bias was observed for TP compared to MPTSS. In-vivo study showed that the subject-variability on turbulence quantification was relatively low for the consistent scan protocol. The in vivo demonstration of the stenosis patient showed that the turbulence analysis could clearly distinguish the difference in all turbulence parameters as they were at least an order of magnitude larger than those from the normal subjects.

Light-based diagnostic methods for the in vivo assessment of initial caries lesions: Laser fluorescence, QLF and OCT.

OBJECTIVES: To evaluate different light-based caries diagnostic methods for assessment of non-cavitated initial carious lesions on smooth surfaces. METHODS: 39 participants were included. For each participant, three regions of interest (ROI) with ICDAS codes 0, 1 or 2 were defined. All ROIs (n = 117) were investigated/imaged with laser fluorescence (LF, DIAGNOdent 2095; KaVo dental GmbH), quantitative light-induced fluorescence (QLF; Biluminator 2+, Inspektor Research Systems B.V.) and spectral-domain optical coherence tomography (SD-OCT; Telesto II, Thorlabs GmbH). The values of LF, ΔF of QLF, and the lesion extent assessed by OCT were categorized. Frequency distribution of LF-/QLF- and OCT-scores was determined for each ICDAS code included. Inter- and intra-examiner reproducibility of QLF and OCT measurements were assessed by unweighted kappa coefficient (ĸ) and Wilcoxon test (α = 0.05). RESULTS: Compared with LF and QLF, OCT showed various manifestations of carious lesions for visually sound ROIs and a larger variation of caries extent in depth within the same ICDAS code groups. Intra-examiner reproducibility ranged between 0.49 and 1.00 for the QLF analysis and between 0.95 and 0.99 for the OCT analysis. Inter-examiner reproducibility ranged between 0.17 and 0.32 for the QLF analysis and between 0.65 and 0.79 for the OCT analysis. CONCLUSION: LF and QLF were insensitive to less pronounced smooth-surface lesions while OCT allowed differentiation based on the penetration depth of the carious lesions. This makes OCT a suitable method to complement conventional visual inspection in order to detect and assess (very) early lesions.

Evaluation of low-viscosity bulk-fill composites regarding marginal and internal adaptation.

This study aimed at evaluating the marginal and internal adaptation of low-viscosity bulk-fill composites to enamel and dentin using a self-etch or an etch-and-rinse adhesive without and with artificial ageing. Hundred and twenty-eight MOD cavities in extracted molars were assigned to eight groups (n = 16), restored with the adhesives OptiBond FL (OFL) or Xeno V+ (X) and two low-viscosity bulk-fill composites SDR or x-tra base, covered with Premise. Tetric EvoCeram Bulk Fill and Premise served as a control. n = 8 per group were subjected to prolonged water storage (180 days) and thermocycling (2500×). Scanning electron microscopy was used to determine marginal gaps (MG) and interfacial adhesive defects (IAD). There were no significant differences between composite types in 44 out of 48 (MG) or 43/48 (IAD) comparisons. More MG were observed with X than with OFL (14 out of 16 comparisons, two significant), while in 16 of 16 comparisons with X more IAD were observed (14 significant). After artificial ageing, MG generally increased (9/16 significant), compared to IAD (one significant). The performance of the investigated composite types concerning the integrity of the tooth-composites interface was comparable. Compared to the 1-step self-etch system, the bond with the 3-step etch-and-rinse adhesive was raised.

In vitro experiments on ICOSA6 4D flow MRI measurement for the quantification of velocity and turbulence parameters.

PURPOSE: To perform comprehensive in vitro experiments using six-directional icosahedral flow encoding (ICOSA6) 4D flow magnetic resonance imaging (MRI) under various scan conditions to analyze the robustness of velocity and turbulence quantification. MATERIALS AND METHODS: In vitro flow phantoms with steady flow rates of 10 and 20 L/min were scanned using both conventional 4D flow MRI and ICOSA6. Experiments focused on comparisons between ICOSA6 and conventional four point (4P) methods, and the effects of contrast agents, velocity encoding range (Venc), and scan direction on velocity and turbulence quantification. RESULTS: The results demonstrated that 1) ICOSA6 improves the velocity-to-noise ratio (VNR) of velocity estimation by 33% (on average) and results in similar turbulent kinetic energy (TKE) estimation as the 4P method. 2) Measurements with a contrast agent resulted in more than a 2.5 fold increase in average VNR. However, the improvement of total TKE quantification was not obvious. 3) TKE estimation was less affected by Venc and the scan direction, whereas turbulence production (TP) estimation was largely affected by these measurement conditions. The effects of Venc and scan direction accounted for less than 11.63% of TKE estimation, but up to 33.89% of TP estimation. CONCLUSION: The ICOSA6 scheme is compatible with conventional 4D flow MRI for velocity and TKE measurement. Contrast agents are effective at increasing VNR, but not signal-to-noise ratio for TKE quantification. The effects of Venc and scan direction influence total TP more than total TKE.

Assessment of non-cavitated root caries lesions by quantitative light-induced fluorescence-An in vivo feasibility study.

OBJECTIVES: To evaluate the reproducibility of quantitative light-induced fluorescence (QLF) for the detection and assessment of demineralization states of non-cavitated root surfaces and to determine the correlation between visual inspection and QLF-analysis. METHODS: 46 exposed non-cavitated root surfaces of 12 participants were classified in three scores: sound (0), lesion ≤ 5 mm (1a), lesion > 5 mm in diameter (1b). Three examiners imaged every root surface three times using QLF (QRayCam) and measured fluorescence loss (ΔF) and lesion volume (ΔQ). The QLF-images were analyzed by three examiners. The intra- and interexaminer reproducibilities were calculated (intraclass correlation coefficient, ICC). The correlation between the scores of root caries and QLF-analysis was determined (rank correlation coefficient, Spearman-Rho ρ). RESULTS: Intra- and interexaminer reproducibility (ICC) was 0.98 and 0.95 for ΔF, 0.94 and 0.91 for ΔQ, respectively. A significant correlation was observed between the scores and ΔF (ρ = -0.53, p < 0.01). CONCLUSION: QLF as a reproducible diagnostic tool enables non-invasive detection and differentiation of non-cavitated root caries lesions on root surfaces in vivo. It can be recommended in addition to the clinical evaluation for prospective follow-up examinations of demineralization states of exposed root surfaces.

Clinical and OCT outcomes of a universal adhesive in a randomized clinical trial after 12 months.

OBJECTIVES: To assess the performance of a universal adhesive in different application modes in non-carious cervical lesions clinically and by optical coherence tomography (OCT). METHODS: 55 adult patients with three non-carious cervical lesions (NCCL) each participated in the study. Lesions were restored with Scotchbond™ Universal (SBU, 3 M) applied in the self-etch (SBU-SE) and the selective-enamel-etch mode (SBU-SEE) in combination with Filtek™ Supreme XTE (3 M). OptiBond™ FL (OFL, Kerr) was used as a control. Restorations were clinically assessed (FDI criteria) after 14 days, 6 and 12 months and in parallel imaged by OCT (interfacial adhesive defects), starting immediately after filling placement. Cumulative failure rates (CFR) and means of interfacial adhesive defect were statistically evaluated. RESULTS: After 12 months, CFRs were lower in the SBU groups (0.0% each) than in the OFL group (20.0%, p = 0.001). Clinically, small marginal fractures occurred three times more often in the SBU-SE than in the SBU-SEE group (p = 0.001). Immediately after filling placement and at each reassessment OCT revealed more interfacial defects at enamel interfaces for SBU/SE compared to SBU/SEE and OFL (pi ≤ 0.044). At dentin/cement more defects were seen with OFL compared to SBU/SE and SBU/SEE (pi ≤ 0.001). Before restoration loss, more interfacial defects appeared compared to remaining restorations (pimmediately/6M = 0.132/0.002). CONCLUSIONS: Clinical evaluation and OCT imaging revealed higher interfacial integrity for SBU in both application modes compared to OFL. OCT detected interfacial bond failures prior to clinical deterioration or restoration loss. CLINICAL SIGNIFICANCE: Scotchbond Universal showed an equivalent or improved bonding performance compared to the reference adhesive. Selective enamel etching is recommended. The parameter interfacial adhesive defect seems to be a valuable predictor for evaluation of adhesive restoration systems.

Effectiveness of caries-preventing agents on initial carious lesions within the scope of orthodontic therapy.

OBJECTIVE: To evaluate the effectiveness of three different caries-preventing agents on artificial caries in a Streptococcus mutans-based caries model. METHODS: Sixty-five caries-free human molar enamel blocks were treated with a demineralization solution and a remineralization solution. The specimens were assigned to the following groups according to the caries-protective product applied: group A, chlorhexidine varnish; group B, fluoride-releasing chemically cured sealant; group C, fluoride-releasing lightcured sealant; group D, positive control (specimens that were subjected to de- and remineralization cycles without treatment with any caries-protective agents); and group E, negative control (specimens that were not subjected to de- and remineralization cycles). Samples in groups A-D were stored in demineralization solution with S. mutans and thereafter in artificial saliva. This procedure was performed for 30 days. Average fluorescence loss (ΔF) and surface size of the lesions were measured using quantitative light-induced fluorescence at baseline and on the 7th, 14th, and 30th days. RESULTS: After 30 days, group A demonstrated a significant increase in ΔF and the surface size of the lesions, no significant difference in comparison with the positive control group, and a significant difference in comparison with the negative control group. Group B showed no significant changes in both parameters at any of the measurement points. While group C showed increased ΔF after 14 days, no significant fluorescence change was observed after 30 days. CONCLUSIONS: Both fluoride-releasing sealants (chemically or light-cured) show anti-cariogenic effects, but the use of chlorhexidine varnish for the purpose of caries protection needs to be reconsidered.

Magnetic Plasmon Networks Programmed by Molecular Self-Assembly.

Nanoscale manipulation of magnetic fields has been a long-term pursuit in plasmonics and metamaterials, as it can enable a range of appealing optical properties, such as high-sensitivity circular dichroism, directional scattering, and low-refractive-index materials. Inspired by the natural magnetism of aromatic molecules, the cyclic ring cluster of plasmonic nanoparticles (NPs) has been suggested as a promising architecture with induced unnatural magnetism, especially at visible frequencies. However, it remains challenging to assemble plasmonic NPs into complex networks exhibiting strong visible magnetism. Here, a DNA-origami-based strategy is introduced to realize molecular self-assembly of NPs forming complex magnetic architectures, exhibiting emergent properties including anti-ferromagnetism, purely magnetic-based Fano resonances, and magnetic surface plasmon polaritons. The basic building block, a gold NP (AuNP) ring consisting of six AuNP seeds, is arranged on a DNA origami frame with nanometer precision. The subsequent hierarchical assembly of the AuNP rings leads to the formation of higher-order networks of clusters and polymeric chains. Strong emergent plasmonic properties are induced by in situ growth of silver upon the AuNP seeds. This work may facilitate the development of a tunable and scalable DNA-based strategy for the assembly of optical magnetic circuitry, as well as plasmonic metamaterials with high fidelity.

Correction to: Internal and marginal adaptation of high-viscosity bulk-fill composites in class II cavities placed with different adhesive strategies.

In the original publication of the article the paragraph "The four resin-based composites…" appearing below the "Materials and methods" section is incomplete. The correct paragraph is provided in this correction below.

Evaluation of calculus imaging on root surfaces by spectral-domain optical coherence tomography.

OBJECTIVE: The aim of this in vitro study was to evaluate the ability of optical coherence tomography (OCT) to display calculus on root surfaces. MATERIAL AND METHODS: Ten teeth with calculus on the root surface were embedded in resin, omitting the root surface. A region of interest (ROI) was marked by small drill holes coronally and apically of the calculus and imaged by spectral-domain optical coherence tomography ([SD OCT], Telesto SP5, centre wavelength 1310 nm) and light microscopy (LM). To evaluate the impact of different fluids on calculus visualisation, using OCT, root surfaces were covered by a layer of NaCl and blood and displayed by OCT. Subsequently, teeth were completely covered with resin and sectioned for histological evaluation. Within the ROI, lengths of root surface and calculus were measured by LM and OCT, and the ratio [%] was calculated. In addition, at three sites of each ROI, agreement of presence and length of calculus was evaluated. Both methods were compared using Pearson's correlation. RESULTS: Regarding the presence of calculus, agreement between LM and OCT was strong (κi = 0.783, p = 0.033), and measurements regarding the length of the calculus were strongly correlated (ri >0.906; pi <0.001). However, the values differed for dry (p = 0.023) and NaCl-covered root surfaces (p = 0.035). CONCLUSION: Calculus on the root surface can be displayed by SD-OCT, which therefore may be suited as imaging technology for subgingival calculus in periodontal pockets.

Visualization of the pulp chamber roof and residual dentin thickness by spectral-domain optical coherence tomography in vitro.

The aim of this study was to evaluate the ability of spectral-domain optical coherence tomography (SD-OCT) to display the roof of the pulp chamber and to estimate the residual dentin thickness (RDT) of the pulp complex. The roots of 20 extracted human molars were embedded in epoxy resin, and crowns were longitudinally sectioned in the mesial-distal direction, exposing the pulp chamber. The coronal part of the crown was removed up to an RDT to the pulp chamber roof of 2 mm. Samples were imaged by SD-OCT from coronal view and by light microscopy (LM) in the sagittal plane. Using a microtome, dentin was subsequently removed in four levels from the occlusal aspect in steps of 250 µm. At each level, RDT was documented and measured by both methods. The data were compared (Spearman's rho correlation coefficient, Wilcoxon signed-rank test). Using OCT, the roof of the pulp chamber was first displayed at a maximum RDT of 1.94 mm. The minimal RDT that could be imaged by OCT was 0.06 mm. Values from both methods were strongly correlated (r, 0.83-0.95; pi ≤ 0.05) and differed significantly for large RDTs (dentin levels 1, 2; pi < 0.05) but not for small RDTs (levels 3, 4; pi ≥ 0.226). The roof of the dental pulp chamber could be already visualized by SD-OCT with a RDT of 1.94 mm. Therefore, the method could be a useful diagnostic tool during the preparation of deep dentin cavities and might help to preserve the integrity of the pulp chamber.

Internal and marginal adaptation of high-viscosity bulk-fill composites in class II cavities placed with different adhesive strategies.

The aim of this study was to evaluate internal and marginal adaptation of high-viscosity bulk-fill composites to enamel and dentin with a self-etch (SE) and an etch-and-rinse adhesive (ER) without and with artificial aging. 128 MOD cavities in extracted human molars were prepared, randomly assigned to 8 groups (n = 16), bonded with either OptiBond FL (OFL, ER) or Xeno V+ (X, SE), and restored in 4 mm horizontal bulk layers with SonicFill (SF), Tetric EvoCeram Bulk fill (TEC), and x-tra fil (XF). Incremental layering technique with Premise (P) served as control. Half of the specimens each (n = 8) were subjected either to water storage (1 day, 37 °C) or prolonged storage (180 days) and thereafter thermocycling. Replicas were analyzed for marginal gap formation. After sectioning, interfacial adhesive defects were assessed. Results were statistical analyzed. (1) Internal adaptation: Except for TEC/OFL at enamel without artificial aging, no significant differences between bulk-fill composites and the control were observed. All groups at dentin with OFL showed less internal adhesive defects than that with X (p < 0.05). (2) Marginal adaptation: No significant differences were observed between bulk-fill composites and control except for P after artificial aging (p > 0.05). All other composites, regardless of artificial aging, formed significantly more marginal gaps at enamel with X compared to with OFL (p ≤ 0.05). Simplified restorations with high-viscosity bulk-fill composite showed comparable internal and marginal adaptation to incrementally placed fillings. A superiority of the 3-step ER approach was seen compared to the 1-step SE adhesive irrespective of the bulk-fill composite used.