Comparison of Blue and Infrared Light Transmission Through Dental Tissues and Restorative Materials

OBJECTIVES

The depth of cure using blue-light photocuring units (BL) is limited by tooth structure and qualities of the restorative material through which the activating wavelength must pass. Recent developments incorporate an infrared (IR) activated upconversion (UC) fluorescence of a lining agent filled with nanocrystals of NaYF4 and doped with YB+3 and Tm+3 that emit both blue and violet light locally at the interface of the liner and restorative resin. The purpose of this study was to evaluate the BL and 975 nm infrared (IR) light power transmission through dental tissues and restorative materials.

METHODS AND MATERIALS

Power transmissions of the IR laser (975 nm) and a monowave blue-only light-curing unit (Bluephase 16i) through dental tissues (enamel, dentin, and enamel/dentin junction, or DEJ), eight (8) various dental resin composites, and eight (8) dental ceramics, each at four thicknesses (1, 2, 3 and 4 mm) were evaluated (n=5) using a thermopile sensor (PM10, Coherent Inc) connected to a laser power meter (Fieldmate, Coherent Inc). Power transmission values of each light source and restorative material were subjected to analysis of variance and Tukey test at a pre-set alpha of 0.05.

RESULTS

A linear correlation (r=0.9884) between the supplied current and emitted IR power of the laser diode was found, showing no statistical power reduction with increased distances (collimated beam). For tooth tissues, the highest power transmissions for both light sources were observed using 1.0 mm enamel while the lowest values were found for 2.0 mm dentin and an association of 2.0 mm DEJ and 1.0 mm dentin. The only group where IR demonstrated significantly higher transmission when compared to BL was 1.0 mm enamel. For all resin composites and dental ceramics, increased thickness resulted in a reduction of IR power transmission (except for EverX Posterior fiber-reinforced composite and e.max HT ceramic). IR resulted in higher transmission through all resin composites, except for Tetric EvoCeram White. The highest BL transmission was observed for SDR Flow, at all thicknesses. Higher IR/BL ratios were observed for EverX Posterior, Herculite Ultra, and Lava Ultimate, while the lowest ratio was observed for Tetric EvoCeram White. Reduced translucency shades within the same material resulted in lower power ratio values, especially for BL transmission. Higher IR/BL ratios were observed for e.Max LT, VitaVM7 Base Dentin, and e.max CAD HT, while the lowest values were found for VitaVM7 Enamel and Paradigm C.

CONCLUSION

IR power transmission through enamel was higher when compared to blue light, while no difference was observed for dentin. The power transmission of IR was higher than BL for resin composites, except for a high value and low chroma shade. Fiber-reinforced resin composite demonstrated the highest IR/BL power transmission ratio. A greater IR/BL ratio was observed for lower translucency ceramics when compared to high translucency.

Effect of Ceramic Conditioners on Surface Morphology, Roughness, Contact Angle, Adhesion, Microstructure, and Composition of CAD/CAM Ceramics

The objective of this study was to investigate the effect of surface treatments in maximum profile valley depth (Rv), surface roughness (Sa), contact angle (Ca), shear bond strength (SBS) of a light-cured resin cement, microstructure, and composition of two CAD/CAM ceramics: Cerec Blocs/Dentsply Sirona (feldspathic - FEL) and Empress CAD/Ivoclar Vivadent (leucite-reinforced - LEU). The ceramic specimens were submitted to six surface treatments: (1) 5% hydrofluoric acid (HF) - 20 seconds; (2) 5% HF - 60 seconds; (3) 10% HF - 20 seconds; (4) 10% HF - 60 seconds; (5) self-etching ceramic primer (MEP) - 20 seconds; and (6) MEP - 60 seconds. Specimens treated with HF received silane application for 1 minute. Rv and Sa were evaluated in a confocal laser microscope (n=10) and the Ca in a goniometer (n=6). For the SBS test, two resin cement cylinders were bonded to each specimen, one tested after 24 hours in distilled water storage (37°C) and the other after one year (n=10). The microstructures and compositions were analyzed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) (n=4). Rv, Sa, and Ca data were analyzed by two-way ANOVA, and the SBS data by three-way ANOVA, all followed by post-hoc Tukey's test (α=0.05). Results: Surface treatments with HF always produced higher Rv and Sa, and lower Ca than MEP 60s for both ceramics. After 1-year water storage, FEL ceramic treated with MEP for 60 seconds produced higher SBS values than HF treatments, whereas for LEU ceramic there were no differences among treatments. Application of MEP for 20 or 60 seconds produced no difference in Rv, Sa, Ca, and SBS for both ceramics. Surface treatments produced considerable differences in ceramic topography, but subtle ones in composition, for both ceramics. Conclusions: The results indicated that for FEL ceramic, MEP application for 60 seconds yielded higher SBS compared with HF etching, while for LEU ceramic the surface treatments did not influence the SBS results.

Effect of High-radiant Emittance and Short Curing Time on Polymerization Shrinkage Vectors of Bulk Fill Composites

PURPOSE

To evaluate the effect of short curing time using a high-radiant emittance light on polymerization shrinkage vectors in different consistency bulk-fill composites (BFRCs) using micro-computed tomography.

METHODS AND MATERIALS

Radiopaque zirconia fillers were homogeneously incorporated and functioned as radiopaque tracers into two regular-paste: TBFill (Tetric EvoCeram Bulk Fill) and TPFill (Tetric PowerFill), and two flowable (n=6): TBFlow (Tetric EvoFlow Bulk Fill) and TPFlow (Tetric PowerFlow) resin composites. Class I cavities (4 mm depth × 4 mm length × 4 mm width) were 3D-printed and filled in a single increment: TBFill and TBFlow were light-activated using a Bluephase Style 20i (10 seconds in high-mode); TPFill and TPFlow were light-activated using a Bluephase PowerCure (three seconds). The same adhesive system (Adhese Universal) was used for all groups. Microcomputed tomography scans were obtained before and after light-activation. Filler particle movement was identified by polymerization shrinkage vectors at five depths (from 0-4 mm): top, top-middle, middle, middle-bottom and bottom.

RESULTS

TPFlow showed the lowest total vector displacement, followed by TBFlow, TBFill and TPFill, significantly different among each other (p<0.05). Generally, BFRCs showed decreased vector displacement with increased depth, and higher displacement at the top-surface (p<0.05). Qualitative analysis showed a similar pattern of vector magnitude and displacement for groups TBFill and TPFill, with displacement vectors on occlusal (top) surfaces toward the center of the restoration from the top to middle areas, and relatively limited displacement at the bottom. TBFlow and TPFlow showed more displacement on the occlusal (top).

CONCLUSIONS

Short curing time with high-radiant emittance on fast-curing BFRCs was shown to be a feasible option in terms of vector displacement. Flowable BFRCs presented lower vector displacement than their regular-viscosity versions.

Effect of Argon Plasma Surface Treatment on Repair of Resin Composite Aged Two Years

OBJECTIVES

To evaluate the effect of argon plasma treatment (PLA) when combined with sandblasting (SAN), silanization (SIL), and hydrophobic bonding resin (HBR) on the shear bond strength (SBS) of a two-year water-aged resin composite bonded to a newly placed composite after 24 hours and one year of water-storage.

METHODS AND MATERIALS

Thirty-six light-cured composite plates (20mm x 20mm x 4mm thick) were obtained and stored at 37°C in distilled water for 2 years. These aged plates were distributed into 6 groups (n=6) according to the surface treatment: no treatment (Negative Control); SAN+SIL+HBR (Positive Control); SAN+PLA+SIL+HBR; PLA+ SIL+HBR; PLA+SIL; PLA+HBR. Fresh resin composite cylinders were built up using silicone molds (hole: 1.5 mm high x 1.5 mm diameter) positioned over the aged plates. Half of the SBS samples were stored in distilled water for 24 hours and loaded until failure, while the other half were stored for 1 year before being tested. Data were submitted to two-way analysis of variance and post-hoc Tukey Test (preset alpha of 0.05).

RESULTS

Positive Control, SAN+PLA+SIL+HBR and PLA+SIL+HBR groups presented higher SBS means at the 24 hour evaluation. After 1 year of water storage, all groups demonstrated significant SBS reduction, with the SAN+PLA+SIL+HBR group presenting the highest SBS.

CONCLUSIONS

Resin plasma treatment in combination with other surface treatments can improve the SBS of composite repairs after one year of water storage. The SBS of the composite repair was not stable over time regardless of the surface treatment.

A survey on psychological distress and problematic smartphone use: two sides of the same coin?

Background

Problematic smartphone use (PSU) is defined as a maladaptive smartphone use causing significant impairment in several areas of the individual and interpersonal functioning. Smartphones allow people to access the internet and social media at all times, providing the illusion of being in constant connection with the world. Literature has shown that maladaptive smartphone use is more frequent in young adults, and it is associated with psychological difficulties such as depression, anxiety, and feelings of tension and emotional discomfort, which can generally be referred to a condition of psychological distress.

Aim

The aim of the study was to investigate the role of psychological distress and possible risk factors associated with PSU, as well as to evaluate the factor structure of the Smartphone Addiction Scale - Short Version (SAS-SV) test Italian translation in a sample of students.

Methods

A sample of 2260 students (aged 18-25 years) filled in a web-based survey that included a sociodemographic questionnaire, also investigating time spent using smartphone and the preferred social media; the SAS-SV, the Internet Addiction Test and the Matthey Generic Mood Questionnaire were also part of the survey.

Results

A multiple logistic regression analysis showed that moderate-high perception of psychological distress, time spent using smartphone overnight and during the day, education, and sex are independent predictors of potential smartphone addiction, as measured by the SAS-SV. An Exploratory Factor Analysis followed by a Confirmatory Factor Analysis showed a reliable two-factor structure of SAS-SV.

Conclusions

The results of the study highlighted predictors that can be useful in prevention, confirming the impact of the extent of time spent using the smartphone, especially at night, and underlining the role of psychological distress in maladaptive smartphone use.

Key messages

The findings raise concerns about the potential spread of smartphone addictive behaviour in Italian young adults. Perceiving a psychological distress condition was associated with potential smartphone addiction. It is important for prevention to have reliable screening tools that are quick and easy to fill out.

POS0876 SARCOPENIA IN MYOSITIS PATIENTS: A MARKER OF MUSCLE DAMAGE ASSOCIATED WITH HANDICAP

Background:

Myositis are systemic autoimmune rare diseases characterized by muscle inflammation and weakness. Even though the signs of active disease have been resolved, myositis patients frequently present residual muscle weakness, decreased physical performance and sustained disability. This condition has been coined on the term “damage” (as opposed to “activity”).

Sarcopenia is a frequent, progressive and generalized skeletal muscle disorder characterized by low muscle strength and mass leading to handicap, decreased quality of life and increased mortality.1

Prevalence and significance of sarcopenia in myositis patients has never been reported.

Objectives:

To study sarcopenia in myositis patients with low or no disease activity.

Methods:

Adult myositis patients (2017 ACR/EULAR criteria), with disease duration greater than 12 months, creatine kinase serum level (CK) less than 500 U/l, stable medication for 6 months were enrolled. Patients with inclusion body myositis were excluded. Total (LM) and appendicular (ALM) muscle mass were measured using dual-energy X-ray absorptiometry (DXA, Hologic) and muscle grip strength was measured using Jamar dynamometer. Sarcopenia was defined according to the EWGSOP2 consensus.1

Results:

29 patients (20 female, 68.9%), with a median age of 61 years (50.5-71) were enrolled. They suffered from dermatomyositis (DM, n=4), immune-mediated necrotizing myopathy (IMNM), n=8), anti-synthetase syndrome (ASS, n=9), scleromyositis (SM, n=8) since 4.7 years (2.8-8.3). At the evaluation, muscle strength assessed with MMT-8 was 139/150 (136-147), MMT-12 was 210/220 (204-216) and CK were 131.5 U/l (105.5-202). Four patients (13.8%) were sarcopenic. Sarcopenic patients were older (73.4 years (66.2-80.5) vs 58.7 years (44.2-79.6), p=0.03), with a longer disease duration (7.3 years (5.3-11.8) vs 4.3 (2.7-8.3), p = 0.1), longer time with increased CK (449 days (169.8-954) vs 255.5 (124-872.8)), higher maximum CK values (6000 U/l (2205-7000) vs 1636 (900-4457)). They suffered from IMNM (2/4, 50%); DM (n=1) and SM (n=1), had more frequently disease-related cardiac involvement (50% vs 4%, p=0.04), and tended to a longer steroid therapy duration (2.4 years (0.8-5) vs 1.8 (1.3-3.9), p=0.9) and a higher number of immunomodulatory drugs (2.5 (2-5.3) vs 2 (2-3), p=0.3).

At the evaluation, sarcopenic patients were globally weaker as highlighted by lower MMT-12 (201 (196.8-206.8) vs 213 (207-217.5), p=0.02). Head flexo-extensors and proximal upper muscles were especially weaker (respectively, p=0.04 and p=0.03). Muscle performance was also lower in sarcopenic patients as assessed by distance covered at 6-minute walk test (6mWT, p=0.003) and number of squats in 30 seconds (p=0.005). Time to drink a glass of water was significantly longer in sarcopenics (p=0.04) even if any patient referred dysphagia. Health assessment questionnaire score was greater (1.4 (0.8-2) vs 0.6 (0.2-1), p=0.04) indicating higher handicap. LM positively correlated with MMT-8 (ρ=0.5, p=0.01) and MMT-12 (ρ=0.5, p=0.004), with number of squats in 30 seconds (ρ=0.7, p=0.0003) and 6mWT distance covered/lower limit (ρ= 0.5, p=0.01). Moreover, LM negatively correlated with time to drink a glass of water (ρ=-0.6, p=0.002).

Conclusion:

Muscle mass measured by DXA is a relevant parameter for muscle damage and disability in myositis patients. Sarcopenic myositis patients represent a subgroup with important muscle damage and handicap.

References:

[1]Cruz-Jentoft AJ et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing. 1 Jan 2019;48(1):16-31.

Disclosure of Interests:

None declared

OP0243 AN APPROACH COMBINING TRANSCRIPTOMIC AND TOPOGRAPHIC ANALYSIS REVEALS A POTENTIAL ROLE OF PROTEASOME AND AUTOPHAGY DEREGULATION IN THE PATHOPHYSIOLOGY OF DERMATOMYOSITIS

Background:

Dermatomyositis (DM) is a rare autoimmune muscle disease characterized by an atrophy and a type-I interferon signature in perifascicular fibers. We recently showed that muscle mitochondrial dysfunction is also a characteristic of this disease that participates to both decrease exercise capacity and maintenance of inflammation (1). Pathophysiological mechanisms underlying these characteristics are unknown.

Objectives:

The objective of this study is to reveal the mechanisms underlying the modifications of perifascicular fibers during DM, taking advantage of a method combining transcriptomic and topographical information.

Methods:

Fourteen patients with recent (<6 months) untreated myositis (DM: n=7, other myositis: n=7) who underwent a biopsy of the deltoid muscle for diagnostic purposes were included. Seven other patients with suspected but not confirmed neuromuscular pathology (normal creatine kinase level, electromyogram and deltoid biopsy) were also included (no myopathy: n=7). Under the control of optical microscopy, perifascicular fibers (about 400 fibers) and endofascicular fibers (about 400 fibers) were microdissected by laser. The transcriptome of endofascicular fibers and perifascicular fibers in all three groups of patients were then obtained by massive sequencing of total messenger RNA. The DAVID database (2) (http://david.abcc.ncifcrf.gov) were used to determine the deregulated molecular pathways in the perifascicular fibers during DM.

Results:

482 transcripts were differently expressed in perifascicular fibers of patients with DM compared to perifascicular fibers of the 2 other groups (348 overexpressed and 134 underexpressed). The most overexpressed transcripts were involved in the type I interferon response while the most underexpressed transcripts were involved in mitochondria and in proteasome functioning. The study of the transcripts differentially expressed in perifasicular versus endofascicular fibers revealed that there is a physiological perifascicular signature: in patients without myopathy, 83 genes were overexpressed and 54 were underexpressed in perifascicular fibers compared to endofascicular fibers. This physiological perifascicular signature was abolished in patient with myositis (DM and other myositis). In the group of patients with DM (but not other myositis), a specific perifascicular signature (18 genes overexpressed and 10 genes underexpressed in perifascicular fibers compared to endofascicular fibers) was identified. The most deregulated transcripts in DM perifascicular fibers were involved in autophagy/mitophagy, mitochondria and proteasome pathways.

Conclusion:

In the physiological state, perifascicular fibers are characterized by a different transcriptomic profile from endofascicular fibers. During DM, this physiological perifascicular signature is abolished and replaced by a transcriptomic signature that reveal a potential role of proteasome and autophagy deregulation in the pathophysiology of DM.

References:

[1]Meyer et al. IFN-β-induced reactive oxygen species and mitochondrial damage contribute to muscle impairment and inflammation maintenance in dermatomyositis Acta Neuropathol. 2017;134:655-666.

[2]Huang, D. W. et al. The DAVID Gene Functional Classification Tool: a novel biological module-centric algorithm to functionally analyze large gene lists. Genome Biol 8, R183 (2007).

Disclosure of Interests:

None declared

OP0247 IN MYOSITIS MUSCLE FIBRE PLAYS A DIRECT AND CRITICAL ROLE IN THERAPEUTIC RESPONSE TO GLUCOCORTICOIDS

Background:

Myositis are rare autoimmune diseases, affecting more women than men, characterized by chronic inflammation of skeletal muscle causing muscle weakness, decreased quality of life and increased mortality.

Glucocorticoids (GC) are potent anti-inflammatory drugs, and are the first line treatment of myositis. They improve muscle strength of myositis patients (therapeutic effect), yet muscle recovery is generally only partial. Moreover, GC have an iatrogenic effect on skeletal muscle fibre leading to steroid myopathy. Thus myositis care has to be improved. Despite the autoimmune terrain of myositis, our team has recently shown that muscle fibres themselves develop immuno-metabolic modifications that participate to muscle weakness and perpetuation of the disease1. GC effects are mediated by the glucocorticoid receptor (GR), which is expressed in various cell types including immune cells and myofibres, but the cells mediating therapeutic responses remain to be determined.

Objectives:

Unravel the mechanisms underlying the therapeutic effect of GC in myositis, particularly elucidate the role of skeletal muscle fibres.

Methods:

Experimental myositis was induced in eight to ten week-old C57BL/6J female mice by a single intradermal injection of part of skeletal muscle fast-type C protein along with Freund’s adjuvant and an intraperitoneal (IP) injection of pertussis toxin, as previously described2. Prednisone (PDN) was administered 14 days (D) after the immunization at 1 mg/kg/day for 7 days by gavage. Mice were euthanized 21 days after myositis induction. Muscle strength was assessed by grip test at D 0, before the 1st PDN administration (D 14) and the day before sacrifice (D 20). To investigate whether the PDN effects are mediated by myofibre, we generated transgenic mice carrying two LoxP sites within the GR gene in muscle, expressing the tamoxifen-inducible Cre-ERT2 recombinase selectively in skeletal muscle fibre (HSA-CreERT2/GR L2/L2). Tamoxifen (1 mg/day for 5 days by IP injection) was administered 9 days after immunization to induce GR ablation selectively in skeletal muscle fibres (GR(i)skm-/- mice). Similar treatments were applied to GR L2/L2 that do not express Cre-ER(T2), and served as controls.

We compared 4 groups of myositis mice, GR L2/L2 treated by PDN (n=9) or vehicle (n=9) and GR(i)skm-/- treated by PDN (n=10) or vehicle (n=10), by grip test and at the histological level (hematoxylin-eosin (HE) and Gomori trichrome (GT) staining). Moreover, LC3 expression was studied by RTqPCR and western blot.

Results:

Muscle strength was decreased in both GR L2/L2 and GR(i)skm-/- myositis mice from D 14 to D 20. GR L2/L2 myositis mice recovered muscle strength after PDN treatment; no significant difference compared to D 0 was detected. In contrast, PDN did not improve muscle strength in GR(i)skm-/- myositis mice (Figure 1).

HE and GT staining did not reveal quantitative differences in inflammatory infiltrate. Necrotic and degenerative fibres were detected in the 4 groups. At RTqPCR, LC3, an autophagy marker, was upregulated in PDN-treated GR L2/L2 myositis mice compared to untreated GR L2/L2 myositis mice; moreover it was 2-fold more expressed in PDN-treated GR L2/L2 myositis mice compared to PDN-treated GR(i)skm-/- mice.

Conclusion:

GR in skeletal muscle fibre is crucial to mediate the therapeutic response to GC in a murine model of myositis. Autophagy is one of the candidate pathways controlled by myofibre GR underlying this effect.

References:

[1]Meyer A et al. IFN-β-induced reactive oxygen species and mitochondrial damage contribute to muscle impairment and inflammation maintenance in dermatomyositis. Acta Neuropathol. 2017 Oct;134(4):655-666.

[2]Sugihara T et al. A new murine model to define the critical pathologic and therapeutic mediators of polymyositis. Arthritis Rheum. 2007 Apr;56(4):1304-14.

Disclosure of Interests:

None declared

Intrapulpal Concentration of Hydrogen Peroxide of Teeth Restored With Bulk Fill and Conventional Bioactive Composites

This study evaluated intrapulpal concentration and hydrogen peroxide (HP) penetration at the interface of teeth restored with bioactive composites, using conventional or bulk-fill composites. Cylindrical cavities were prepared on the buccal surface of bovine incisor crowns (n=20) and restored with: resin modified glass-ionomer (RMGI, Riva Light Cure, SDI), non-bioactive bulk-fill composite (FB, Filtek Bulk, 3M Oral Care), non-bioactive conventional composite (FZ, Filtek Z350, 3M Oral Care), bioactive bulk-fill composite (AC, Activa BioActive, Pulpedent), and bioactive conventional composite (BII, Beautifil II, Shofu). After 5,000 thermal cycles, restorations (n=10) were exposed to high (35% HP [4 applications of 8 min/session-4 sessions]) or low (9.5% HP [30 min/day-14 days]) concentration bleaching protocols. After the last bleaching application, the HP intrapulpal concentration was determined. Additional teeth were restored, pigmented with rhodamine B solution, and HP penetration around the interface was observed under laser scanning confocal fluorescence microscopy (LSCFM, n=3). The presence of gaps at the interface was observed on replicas of the cross-sectioned samples under scanning electron microscopy (SEM, n=5). Data were submitted to one-way (gap analysis) and twoway analysis of variance (ANOVA; HP intrapulpal concentration) and Tukey test (α=0.05). The LSCFM images were qualitatively analyzed. The restored teeth submitted to 35% HP presented higher HP intrapulpal concentration than teeth submitted to 9.5% HP (p<0.05). No differences in HP intrapulpal concentration was observed among groups (p>0.05) when exposed to 9.5% HP. Lower HP intrapulpal concentration was observed for teeth restored with RMGI exposed to HP 35%, when compared with teeth restored with nonbioactive conventional (FZ; p=0.004) and bulk-fill composites (FB; p=0.01). No gap formation was observed at the outer enamel adhesive interface for all restorative materials. LSCFM images showed that 35% HP promoted greater degradation of rhodamine B at the enamel, except for RMGI. In this context, RMGI promoted lower HP intrapulpal concentration than non-bioactive conventional and bulk-fill composites.

Effect of Shortened Light-Curing Modes on Bulk-Fill Resin Composites

CLINICAL RELEVANCE

Shortened light curing does not affect volumetric polymerization shrinkage or cohesive tensile strength but negatively affects the shear bond strength of some bulk-fill resin composites. When performing shortened light curing, clinicians should be aware of the light output of their light-curing units.

SUMMARY

Purpose: To evaluate volumetric polymerization shrinkage (VPS), shear bond strength (SBS) to dentin, and cohesive tensile strength (CTS) of bulk-fill resin composites (BFRCs) light activated by different modes.Methods and Materials: Six groups were evaluated: Tetric EvoCeram bulk fill + high mode (10 seconds; TEC H10), Tetric EvoFlow bulk fill + high mode (TEF H10), experimental bulk fill + high mode (TEE H10), Tetric EvoCeram bulk fill + turbo mode (five seconds; TEC T5), Tetric EvoFlow bulk fill + turbo mode (TEF T5), and experimental bulk fill + turbo mode (TEE T5). Bluephase Style 20i and Adhese Universal Vivapen were used for all groups. All BFRC samples were built up on human molar bur-prepared occlusal cavities. VPS% and location were evaluated through micro-computed tomography. SBS and CTS tests were performed 24 hours after storage or after 5000 thermal cycles; fracture mode was analyzed for SBS.Results: Both TEC H10 and TEE H10 presented lower VPS% than TEF H10. However, no significant differences were observed with the turbo-curing mode. No differences were observed for the same BFRC within curing modes. Occlusal shrinkage was mostly observed. Regarding SBS, thermal cycling (TC) affected all groups. Without TC, all groups showed higher SBS values for high mode than turbo mode, while with TC, only TEC showed decreased SBS from high mode to turbo modes; modes of fracture were predominantly adhesive. For CTS, TC affected all groups except TEE H10. In general, no differences were observed between groups when comparing the curing modes.Conclusions: Increased light output with a shortened curing time did not jeopardize the VPS and SBS properties of the BFRCs, although a decreased SBS was observed in some groups. TEE generally showed similar or improved values for the tested properties in a shortened light-curing time. The VPS was mostly affected by the materials tested, whereas the SBS was affected by the materials, curing modes, and TC. The CTS was not affected by the curing modes.

Does the Type of Solvent in Dental Adhesives Influence the Clinical Performance of Composite Restorations Placed in Noncarious Cervical Lesions? A Systematic Review and Meta-analysis

CLINICAL RELEVANCE

According to the clinical and scientific evidence presented in this systematic review and meta-analysis, dental adhesives containing either organic solvent (acetone or alcohol) can be used to achieve similar clinical performance and longevity of composite restorations.

SUMMARY

Objectives: This systematic review and meta-analysis compared the clinical performance and survival rates of composite restorations placed in noncarious cervical lesions (NCCLs) using dental adhesives containing acetone or alcohol-based solvents.Methods and Materials: PubMed, Scopus, Web of Science, Virtual Health Library (VHL) LILACS, Cochrane Library, OpenGrey, Clinical Trials, and Rebec were searched. MeSH terms, supplementary concepts, synonyms, and free keywords were used in the search strategy. All references were crosschecked by two independent investigators following the PICOS strategy (population, NCCLs; intervention, acetone-based bonding agent; comparison, alcohol-based bonding agent; outcome, clinical evaluation parameters and survival rates; study design, randomized controlled clinical trials). Cochrane Collaboration's tool was used to assess risk of bias, and two distinct meta-analyses were performed using the RevMan software. The prevalence of success and the total number of restorations for each group (acetone- or alcohol-based) were used to calculate the risk difference at a confidence interval of 95%. Random-effects models were applied, and heterogeneity was assessed using the I2 index in the pooled and subgrouped meta-analyses. The certainty of evidence was evaluated through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.Results: A total of 7876 studies were retrieved, from which 27 studies were selected for the systematic review. Ten studies were classified as "low risk of bias" and included in the meta-analyses. Overall heterogeneity was not significant (I2 = 0.00%). The clinical performance of restorations placed with bonding agents based on both solvents for each of the available parameters presented no statistical significance for any of the meta-analyses (p>0.05).Conclusion: Scientific evidence suggests composite restorations placed with acetone or alcohol-based dental adhesives present similar clinical performance and survival rates in NCCLs.

External Marginal Gap Evaluation of Different Resin-filling Techniques for Class II Restorations-A Micro-CT and SEM Analysis

CLINICAL RELEVANCE

Secondary caries are the main reason for the failure of restorations, class II being the most affected. Techniques that promote less gap percentage are important. Flowable bulk fill composites used at such locations have been shown to decrease gap formation while being a faster procedure than an incremental technique.

SUMMARY

THU0344 CLINICAL AND HISTOLOGICAL SPECTRUM OF ANTI-MI2 DERMATOMYOSITIS: A MULTICENTRE RETROSPECTIVE COHORT

Background:

Dermatomyositis (DM) shows a wide clinical spectrum that seems to be different based on the type of autoantibody status. Furthermore, less is known regarding to the histopathology of different serological subsets of DM

Objectives:

The aim of our study was to investigate clinical and histopathological hallmarks in adult DM patients positive for anti-Mi2 (Mi2+) antibody compared to DM patients negative for anti-Mi2 (Mi2-)

Methods:

All clinical data of adult DM patients admitted in three tertiary Rheumatology Units, who fulfilled EULAR/ACR 2017 classification criteria1, were included in this study. Overlap syndrome and antisynthetase syndrome were exclusion criterion. Serum samples were tested in the local reference laboratories using line immunoassays methods for Myositis specific and associated antibodies. Histopathological study was carried out from muscle biopsies performed for diagnostic purpose in outpatient clinic of Bari (Italy) University. Quantitative analysis was performed for myofiber and capillary features, whereas semi-quantitative analysis (score from 0 to 3) was performed for inflammatory cells infiltrate, both at endomysial and perimysial sites

Results:

A total of 95 DM patients, followed for a median (IQR) follow-up of 28 (9-85) months, were analyzed. Of these, 23 (24.2%) patients (87% female, mean age at onset 55.4±16.2 years) were anti-Mi2+, while 72 (75.8%) patients were Mi2- (72.2% female, mean age at onset 55.2±17 years). All Mi2+ patients showed muscle involvement. Moreover, Mi2+ DM showed higher levels of serum creatine kinase (CK) at onset compared to Mi2- (CK (IQR): 2649 UI/l (1130-6000) vs 575 UI/l (164-1617), p<0.001). Prevalence of interstitial lung disease (ILD) was lower in Mi2+ patients (8.7% vs 30.6%, p=0.05), and no case of rapidly progressive ILD (RP-ILD) was found. Survival analysis at 5-years follow-up highlighted good survival for Mi2+ patients, but not different from Mi2- (95.7% vs 83.1%, p=0.151). Multivariate analysis showed that age at onset (HR:1.07), RP-ILD (HR:36.2) and cancer associated myositis (HR:6.1) correlated with a poor prognosis. Finally, a total of 26 biopsies (12 Mi2+ and 14 Mi2-) were included into the histological analysis showing higher prevalence of necrotic/degenerating myofibers (median (IQR) 2.6 (0.7-11)% vs 0.6 (0.4-1.1)%, p=0.009) and sarcoplasmic deposit of membrane attack complex (MAC) (median (IQR) 0.2 (0-1.2)% vs (0(0-0)%,p=0.009) in Mi2+ patients. In addition, the endomysial macrophage score was higher in Mi-2+ patients (median 1.5 (0.25-2) vs (0.5 (0-1), p=0.031)

Conclusion:

Mi2+ patients represent a specific DM subset with higher muscle damage, sarcoplasmic MAC deposits and endomysial macrophages infiltration as histological hallmarks

References:

[1]Ann Rheum Dis. 2017 Dec;76(12):1955-1964

Disclosure of Interests:

Marco Fornaro: None declared, Francesco Girolamo: None declared, Lorenzo Cavagna: None declared, Franco Franceschini: None declared, margherita giannini: None declared, Giovanni Zanframundo: None declared, Micaela Fredi: None declared, Marilin Tampoia: None declared, Angela Amati: None declared, Luigi Serlenga: None declared, Anna Lia: None declared, Liala Moschetti: None declared, Dario Dabbicco: None declared, Laura Coladonato: None declared, Florenzo Iannone Consultant of: Speaker and consulting fees from AbbVie, Eli Lilly, Novartis, Pfizer, Roche, Sanofi, UCB, MSD, Speakers bureau: Speaker and consulting fees from AbbVie, Eli Lilly, Novartis, Pfizer, Roche, Sanofi, UCB, MSD

FRI0249 IN MYOSITIS PATIENTS, SJÖGREN’S SYNDROME IS ASSOCIATED WITH INCLUSION BODY MYOSITIS AND WITH ANTI-CN1A ANTIBODIES INDEPENDENTLY OF THE MYOSITIS SUBTYPE

Background:

Myositis are characterized by weakness and muscle inflammation. They encompass heterogeneous conditions, which include dermatomyositis (DM), inclusion body myositis (IBM) and polymyositis (PM) according to the EULAR/ACR 2017 criteria. We recently recorded a high prevalence of IBM in a cohort of primary Sjögren’s syndrome (SS) (1). The signification of SS in the setting of myositis is unanswered.

Objectives:

To refine the signification of SS in the setting of myositis.

Methods:

Among a monocentric myositis cohort (according to the EULAR/ACR 2017 criteria), SS patients (according to the ACR/EULAR 2016 criteria) were identified (myositis/SS+ group) and compared to myositis patients without SS (myositis/SS- group).

Results:

Among 414 myositis patients, SS criteria were available for 96 patients. Thirty two (33%) presented SS. Patients with SS tended to be more frequently women (F/M ratio 9.7 vs 3.0, p = 0.07). Age at diagnosis of myositis was similar in both groups (53 years [range 21-74] vs 53 years [range 16-77], p = 0.51).

Myositis subtypes repartition (as defined by EULAR/ACR 2017 criteria) was different in myositis/SS+ and myositis/SS- groups (p = 0.021), IBM being four-fold more prevalent in myositis/SS+ group (25% vs 6%, p = 0.018). Accordingly, the delay between the first muscle symptoms and myositis diagnosis was longer in myositis/SS+ group (7 months [0-336] vs 4 months [0-122], p = 0.041). Moreover, aside anti-cN1A antibodies, myositis-specific antibodies were less frequently found in myositis/SS+ patients than in myositis/SS- ones (16/32 [50%] vs 46/64 [72%], p = 0.035).

Anti-cN1A antibodies were more prevalent in myositis/SS+ patients (33% vs 5.8%, p = 0.0032). However, in myositis/SS+ group, anti-cN1A were frequent in each of the EULAR/ACR 2017 myositis subtypes and the association between SS and anti-cN1A positivity was maintained in a multivariate analysis adjusted with the diagnosis of IBM (p = 0.023).

Seven of the myositis/SS+ patients (22%) had systemic involvement typical of SS (vs 6 [9%] of the myositis/SS- patients, p = 0.12) including polyneuropathy (6 [20%] vs 6 [10%]) and type 2 cryoglobulinaemic vasculitis (1 [3%] vs 1 [1.6%]). In addition, 2 (6%) myositis/SS+ patients developed a lymphoma (one B diffuse large cell lymphoma of the parotid and one non-Hodgkin lymphoma), vs none of the myositis/SS- patients (p = 0.11). Only one (3%) of the myositis/SS+ patients developed myositis-associated cancer (diagnosed within 3 years of myositis diagnosis) versus 6 (9%) of the myositis/SS- patients (p = 0.66).

Aside hydroxychloroquine, more frequently used in myositis/SS+ group (38% vs 16%, p = 0.018), no significant difference was found in the management of the patients (taking into account the myositis subtype).

Conclusion:

Myositis patients with SS have more frequently IBM than myositis patients without SS. They also have more frequently anti-cN1A antibodies, independently of the myositis subtype. They might develop systemic complications of SS.

References:

[1]Felten R, Seror R, Vittecoq O, Hachulla E, Perdriger A, Dieude P, et al. SAT0470 Myositis, often suspected, is actually rare in primary Sjögren’s syndrome: data from the French cohort ASSESS. In BMJ Publishing Group Ltd and European League Against Rheumatism; 2018. p. 1093.1–1093. Available from:http://ard.bmj.com/lookup/doi/10.1136/annrheumdis-2018-eular.2945

Disclosure of Interests:

Dan LEVY: None declared, Benoit Nespola: None declared, Margherita Giannini: None declared, Renaud FELTEN: None declared, Coralie Varoquier: None declared, Marina Rinagel: None declared, Anne-Sophie Korganow: None declared, Vincent Poindron: None declared, Thierry Martin: None declared, Francois Maurier: None declared, Hassam Chereih: None declared, Bastien Bouldoires: None declared, Baptiste Hervier: None declared, Cédric Lenormand: None declared, Laurent Arnaud: None declared, Bernard Geny: None declared, Jean Sibilia: None declared, Jacques-Eric Gottenberg Grant/research support from: BMS, Pfizer, Consultant of: BMS, Sanofi-Genzyme, UCB, Speakers bureau: Abbvie, Eli Lilly and Co., Roche, Sanofi-Genzyme, UCB, alain meyer: None declared

Influence of Multiple Peak Light-emitting-diode Curing Unit Beam Homogenization Tips on Microhardness of Resin Composites

This study evaluated the effect of light curing unit (LCU) guide type (regular or homogenizing) on top and bottom microhardness of conventional and bulk-fill resin-based composites (RBCs). A polywave light-emitting-diode (LED) LCU (Bluephase Style, Ivoclar Vivadent AG) was used with two different light guides: a regular tip (RT, 935 mW/cm2 emittance) and a homogenizer tip (HT, 851 mW/cm2 emittance). Two conventional RBCs (Herculite Ultra [HER], Kerr Corp; Tetric EvoCeram [TEC], Ivoclar Vivadent AG) and two bulk-fill RBCs (SonicFill [SOF], Kerr Corp; Tetric EvoCeram Bulk Fill [TBF], Ivoclar Vivadent AG) were tested. Disc-shaped samples (10 mm Ø), 2-mm thick for conventional composites and 4-mm thick for bulk-fill composites were prepared. Samples were light cured according to manufacturer-recommended times. Knoop microhardness values (KHN) were obtained on the top and bottom surfaces of each specimen at locations correlated with the output of the three LED chips emitting blue (456 nm) or violet light (409 nm). Beam profile analysis using both light guides was also performed. Microhardness of each composite was analyzed using three-way analysis of variance and Tukey honestly significant difference post hoc test (α=0.05). Beam profile images showed better light distribution across the surface of the HT light guide. Use of the HT decreased KHN of HER at the locations of the blue LED chips at bottom of the sample but had no effect on the top surface. For TEC, use of HT increased KHN of all three LED locations at the top surface. Use of the HT increased KHN of SOF at locations corresponding to one of the blue and the violet LED chips at the bottom surface. For TBF, HT increased KHN at all top surface locations. All RBCs showed higher mean KHN at the top compared with the bottom surfaces. In general, all composites presented a higher KHN at the blue LED areas regardless of the surface or the tip used. Results suggest that the homogenizer light guide resulted in significantly increased microhardness at the top, in composite resins containing alternative photoinitiators; however, that effect was not observed at the bottom surfaces.

Effect of Curing Light and Exposure Time on the Polymerization of Bulk-Fill Resin-Based Composites in Molar Teeth

OBJECTIVES

This study examined the influence of different light-curing units (LCUs) and exposure times on the microhardness across bulk-fill resin-based composite (RBC) restorations in a molar tooth.

METHODS AND MATERIALS

Tip diameter, radiant power, radiant exitance, emission spectra, and light beam profile were measured on two single-emission-peak LCUs (Celalux 3 and DeepCure-S) and two multiple-peak LCUs (Bluephase 20i and Valo Grand). A mold was made using a human molar that had a 12-mm mesial-distal length, a 2.5-mm deep occlusal box, and two 4.5-mm deep proximal boxes. Two bulk-fill RBCs (Filtek Bulk Fill Posterior and Tetric EvoCeram Bulk Fill) were photoactivated for 10 seconds and for 20 seconds, with the light guide positioned at the center of the occlusal surface. Microhardness was then measured across the transverse surface of the restorations. The light that reached the bottom of the proximal boxes was examined. Data were statistically analyzed with the Student t-test, two-way analysis of variance, and the Tukey post hoc test (α=0.05).

RESULTS

The four LCUs were different regarding all the tested characteristics. Even when using LCUs with wide tips and a homogeneous beam profile, there were significant differences in the microhardness results obtained at the central and proximal regions of the RBCs (p<0.05). LCUs with wider tips used for 20 seconds produced higher microhardness values (p<0.05). The multiple-peak LCUs produced greater hardness values in Tetric EvoCeram Bulk Fill than did the single-emission-peak LCUs (Celalux 3 and DeepCure-S). Results for the light measured at the bottom of proximal boxes showed that little light reached these regions when the light tip was positioned at the center of restorations.

CONCLUSIONS

Curing lights with wide tips, homogeneous light beam profiles, and longer exposure times are preferred when light-curing large MOD restorations. Light curing from more than one position may be required for adequate photopolymerization.

In Vitro Evaluation of Surface Properties and Wear Resistance of Conventional and Bulk-fill Resin-based Composites After Brushing With a Dentifrice

Objectives:

This study evaluated the effect of toothbrushing with a dentifrice on gloss, roughness profile, surface roughness, and wear of conventional and bulk-fill resin-based composites.

Methods and Materials:

Gloss and surface roughness of resin-based composites (RBCs; Admira Fusion X-tra, Aura Bulk Fill, Filtek Bulk Fill Flowable, Filtek Bulk Fill Posterior Restorative, Filtek Supreme Ultra, Herculite Ultra, Mosaic Enamel, SDR flow+, Sonic Fill 2, Tetric EvoFlow Bulk Fill and Tetric EvoCeram Bulk Fill) were analyzed before and after brushing; the roughness profile and wear were also determined after toothbrushing. Representative three-dimensional images of the surface loss and images comparing the unbrushed and brushed surfaces were also compared. Analysis of variance and Tukey post hoc tests were applied (α=0.05) to the gloss, surface roughness, roughness profile, and surface loss data. Pearson's correlation test was used to determine the correlation between gloss and surface roughness, surface loss and percentage of gloss decrease after brushing, and surface loss and surface roughness after brushing.

Results:

For all RBCs tested after 20,000 brushing cycles, the gloss was reduced and the surface roughness increased (p&lt;0.05). However, the roughness profile and the amount of surface loss were dependent on the RBC brand. Admira Fusion X-tra, Aura, Tetric EvoCeram Bulk Fill, and Tetric EvoFlow Bulk Fill showed the deepest areas of wear (p&lt;0.05). A significant negative correlation was found between gloss and surface roughness, and a weak correlation was found between the decrease in gloss and the extent of surface loss, and any increase in surface roughness and the surface loss.

Conclusions:

Toothbrushing with a dentifrice reduced the gloss, increased the surface roughness, and caused loss at the surface of all the RBCs tested. Considering all the properties tested, Mosaic Enamel exhibited excellent gloss retention and a low roughness profile and wear, while Admira Fusion X-tra exhibited the greatest decrease in gloss, the highest roughness profile, and the most wear.

Nanogel-Based Filler-Matrix Interphase for Polymerization Stress Reduction

A novel filler-resin matrix interphase structure was developed and evaluated for dental composite restoratives. Nanogel additives were chemically attached to the filler surface to use this created interphase as a potential source of compliance to minimize stress development during polymerization. In addition, we evaluated the effects of free nanogel dispersion into the resin matrix, combined or not with nanogel-modified fillers. Nanogels with varied characteristics were synthesized (i.e., size, 5 and 11 nm; glass transition temperature, 28 °C to 65 °C). Glass fillers were treated with trimethoxyvinylsilane and further reacted with thiol-functionalized nanogels via a free radical thiol-ene reaction. γ-Methacryloxypropyltrimethoxysilane-surface treated fillers were used as a control. Composites were formulated with BisGMA/TEGDMA resin blend with 60 wt% fillers with nanogel-modified fillers and/or free nanogel additives at 15 wt% in the resin phase. Polymerization kinetics, polymerization stress, volumetric shrinkage, and rheological and mechanical properties were evaluated to provide comprehensive characterization. Nanogel-modified fillers significantly reduced the polymerization stress from 2.2 MPa to 1.7 to 1.4 MPa, resulting in 20% stress reduction. A significantly greater nanogel content was required to generate the same magnitude stress reduction when the nanogels were dispersed only in the resin phase. When the nanogel-modified filler surface treatment and resin-dispersed nanogel strategies were combined, there was a stress reduction of 50% (values of 1.2 to 1.1 MPa). Polymerization rate and volumetric shrinkage were significantly reduced for systems with nanogel additives into the resin. Notably, the flexural modulus of the materials was not compromised, although a slight reduction in flexural strength associated with the nanogel-modified interphase was observed. Overall, modest amounts of free nanogel additives in the resin phase can be effectively combined with a limited nanogel content filler-resin interphase to lower volumetric shrinkage and dramatically reduce overall polymerization stress of composites.

Effect of Argon Plasma Surface Treatment on Bond Strength of Resin Composite Repair

Objectives:

This study evaluated the effect of argon plasma treatment (PLA) and its combination with sandblasting (SAN), silanization (SIL), and hydrophobic bonding resin (HBR) application on the micro-shear bond strength of water-aged restorative resin composite to a newly placed composite, simulating restoration repair.

Methods and Materials:

Forty-five light-cured composite plates (20-mm long × 20-mm wide × 4-mm thick) were fabricated using a hybrid composite and stored at 37°C in distilled water for six months. The aged composite surfaces were treated according to the following experimental groups, varying both treatment and order of application: 1) SAN + SIL + HBR (control), 2) SAN + PLA for 30 seconds + SIL + HBR, 3) SAN + SIL + PLA + HBR, 4) PLA + SIL + HBR, 5) PLA + SIL, 6) PLA + HBR, 7) SIL + PLA + HBR, 8) SIL + PLA, and 9) PLA. After the surface treatments, four fresh resin composite cylinders (1.5-mm high × 1.5-mm diameter) of the same composite were built on each aged composite surface using a silicone mold. After water storage for 24 hours or one year, the specimens were submitted to shear bond strength testing. Data were statistically analyzed by two-way analysis of variance and Tukey's test (5%).

Results:

Groups 1, 2, and 4 presented significantly higher bond strength means at 24 hours, although group 4 did not differ from group 7. Groups 5, 8, and 9 demonstrated significantly lower means than the other groups. Even though groups 1 and 2 had a significant bond strength reduction after 1 year, they still demonstrated higher bond strength at one year of storage.

Conclusions:

While PLA application combined with surface treatment methods demonstrated high bond strength results, this treatment alone was not as beneficial as other methods that included SAN, SIL and HBR.

Benefits of Nonthermal Atmospheric Plasma Treatment on Dentin Adhesion

OBJECTIVES:

This study aimed to evaluate the influence of two nonthermal atmospheric plasma (NTAP) application times and two storage times on the microtensile bond strength (μTBS) to dentin. The influence of NTAP on the mechanical properties of the dentin-resin interface was studied by analyzing nanohardness (NH) and Young's modulus (YM). Water contact angles of pretreated dentin and hydroxyapatite blocks were also measured to assess possible alterations in the surface hydrophilicity upon NTAP.

METHODS AND MATERIALS:

Forty-eight human molars were used in a split-tooth design (n=8). Midcoronal exposed dentin was flattened by a 600-grit SiC paper. One-half of each dentin surface received phosphoric acid conditioning, while the other half was covered with a metallic barrier and remained unetched. Afterward, NTAP was applied on the entire dentin surface (etched or not) for 10 or 30 seconds. The control groups did not receive NTAP treatment. Scotchbond Universal (SBU; 3M ESPE) and a resin-based composite were applied to dentin following the manufacturer's instructions. After 24 hours of water storage at 37°C, the specimens were sectioned perpendicular to the interface to obtain approximately six specimens or bonded beams (approximately 0.9 mm² in cross-sectional area) representing the etch-and-rinse (ER) approach and another six specimens representing the self-etch (SE) approach. Half of the μTBS specimens were immediately loaded until failure, while the other half were first stored in deionized water for two years. Three other bonded teeth were selected from each group (n=3) for NH and YM evaluation. Water contact-angle analysis was conducted using a CAM200 (KSV Nima) goniometer. Droplet images of dentin and hydroxyapatite surfaces with or without 10 or 30 seconds of plasma treatment were captured at different water-deposition times (5 to 55 seconds).

RESULTS:

Two-way analysis of variance revealed significant differences in μTBS of SBU to dentin after two years of water storage in the SE approach, without differences among treatments. After two years of water aging, the ER control and ER NTAP 10-second groups showed lower μTBS means compared with the ER NTAP 30-second treated group. Nonthermal atmospheric plasma resulted in higher NH and YM for the hybrid layer. The influence of plasma treatment in hydrophilicity was more evident in the hydroxyapatite samples. Dentin hydrophilicity increased slightly after 10 seconds of NTAP, but the difference was higher when the plasma was used for 30 seconds.

CONCLUSIONS:

Dentin NTAP treatment for 30 seconds contributed to higher μTBS after two years of water storage in the ER approach, while no difference was observed among treatments in the SE evaluation. This result might be correlated to the increase in nanohardness and Young's modulus of the hybrid layer and to better adhesive infiltration, since dentin hydrophilicity was also improved. Although some effects were observed using NTAP for 10 seconds, the results suggest that 30 seconds is the most indicated treatment time.

Chemical Interaction and Interface Analysis of Self-Etch Adhesives Containing 10-MDP and Methacrylamide With the Dentin in Noncarious Cervical Lesions

Objectives:

To characterize the chemical interactions and analyze the interface of adhesive systems containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) and N-methacryloyl glycine (methacrylamide) functional monomers with the dentin in noncarious cervical lesions (NCCLs) compared with artificial defects (ADs).

Methods and Materials:

Twenty human teeth with natural NCCLs on the buccal surface were used. Class V cavities, similar to NCCLs, were created on the lingual surface to serve as controls. Teeth were randomly allocated to two groups according to the functional monomer in the adhesive (N=10): G1, 10-MDP; and G2, methacrylamide. NCCLs and ADs were characterized by their mineral composition (MC) and degree of demineralization (DD) using micro-Raman spectroscopy, adhesive/dentin chemical interactions (CIs) were assessed with infrared photoacoustic spectroscopy, and interface morphology was evaluated with scanning electron and light microscopy. MC, CI, and DD data were submitted to Shapiro-Wilk and Student t-tests (p&lt;0.05).

Results:

Compared with ADs, dentin in NCCLs was hypermineralized (p&lt;0.05). In G1, CI, and DD in the first 2 μm, and adhesive projections in NCCLs and ADs interfaces were similar. Additionally, a thin layer of dentin collagen was observed in ADs, while it was hardly present in NCCLs. In G2, although CI could not be identified, changes in the mineral components were observed. The DD in the ADs and NCCLs were statistically similar, while SEM showed a lack of adhesion at NCCLs interface. DD and collagen exposure in the ADs and NCCLs were more pronounced than in G1.

Conclusions:

Results suggest that the G1 adhesive could be applied directly on the superficial sclerotic layer in NCCLs. In contrast, previous cavity preparation should be conducted to improve the micromechanical interaction of G2 with the dentin.

Stability of the Light Output, Oral Cavity Tip Accessibility in Posterior Region and Emission Spectrum of Light-Curing Units

Objectives: 

This study evaluated the light output from six light-emitting diode dental curing lights after 25 consecutive light exposures without recharging the battery, tip accessibility in the posterior region, and light beam spread from light-curing units.

Methods: 

Irradiance, spectral peak, and radiant exposure were measured with the battery fully charged (Bluephase Style, ESPE Cordless, Elipar S10, Demi Ultra, Valo Cordless, and Radii-Cal) and monitored for 25 light exposures (each lasting 10 seconds). The tip diameter was measured to identify the beam size and the ability of the six light-curing units to irradiate all areas of the lower second molar in the standard output setting.

Results: 

Four curing lights delivered a single peak wavelength from 454 to 462 nm, and two (Bluephase Style and Valo Cordless) delivered multiple emission peaks (at 410 and 458 nm and 400, 450, and 460 nm, respectively). The irradiance and radiant exposure always decreased after 25 exposures by 2% to 8%, depending on the light unit; however, only ESPE Cordless, Valo Cordless, and Radii-Cal presented a statistical difference between the first and the last exposure. The tip diameter ranged from 6.77 mm to 9.40 mm. The Radii-Cal delivered the lowest radiant exposure and irradiance. This light was also unable to access all the teeth with the tip parallel to the occlusal surface of the tooth.

Conclusion: 

Not all of the blue-emitting lights deliver the same emission spectra, and some curing lights delivered a lower irradiance (as much as 8% lower) after the 25th exposure.

Conservative Treatment for T2-T4 Bladder Cancer with Primary Chemotherapy and Radiotherapy: A Pilot Study

Aims and Background

After radical cystectomy, with or without pelvic radiotherapy, more than 50 % of patients affected by infiltrating bladder cancer died of distant metastases. Polychemotherapy yields 25 % complete remissions (CR) in patients with invasive transitional cell bladder carcinoma; although many concerns exist about the duration of such CR. This study was undertaken with the aim of evaluating the efficacy and safety of an integrated chemo-radio-therapeutic treatment, in order to broaden indications to a conservative surgical therapy.

Methods

Thirty-three consecutive patients with bladder urothelial cancer T2-T4, N0, M0, have been treated. Patients received neoadjuvant chemotherapy (rescue-M-VEC) consisted of methotrexate 30 mg/sqm plus folinic acid 15 mg after 24 h on days 1, 15, 22; vinblastine 3 mg/sqm on days 1, 15 and 22; epidoxorubicin 30 mg/sqm on day 1; cisplatin 70 mg/sqm on day 1. This cycle was repeated on day 29. After 2 cycles of rescue-M-VEC, patients underwent pelvic cobalt teletherapy 40 Gy combined with low dose cisplatin 25 mg/sqm/week. After restaging, responding patients underwent further radiation therapy (24 Gy) as booster consolidation.

Results

After 2 cycles of chemotherapy and pelvic radiotherapy 14/31 evaluable patients (45.2 %) achieved CR and 11/31 (35.4 %) partial remission, with an overall response rate of 80.6 % (25/31). With a median follow up of 21 months the actuarial survival rate at 24 months was equal to 79.8 %. Eleven radical cystectomies were performed, 6 of which at restaging in non responding patients and 5 during the follow up due to relapse. Of the 25 patients selected for bladder conservation, 12 (48 %) have not yet shown relapses. Three out of 31 (9.7 %) patients died of distant metastases. No severe toxicity has been observed: moreover no patient developed stomatitis after chemotherapy.

Conclusions

Our results seem encouraging but longer follow-up and further phase III studies need to be carried out to demonstrate the feasibility of conservative treatment in muscle infiltrating bladder cancer.

Potência Radiante, Irradiância e Espectro de Emissão de 22 Fontes de Fotoativação Utilizadas no Brasil

O trabalho mediu a potencia radiante, a irradiância e o espectro de emissão de 22 LCUs do mercado brasileiro. Foi medida a área das pontas (cm2) para calcular a irradiância a partir da potencia radiante (mW), que foi obtida por um medidor de potencia laser do laboratório. O MARC- Patient Simulator (MARC- PS) com espectrômetro de grau (USB4000, Ocean Optics) foi utilizado para medir o espectro no sensor anterior e posterior. Os dados foram analisados utilizando ANOVA two-way e os dados da potencia radiante foram analisados por ANOVA one-way seguida pelo teste de Tukey (a 0,05). Valo, Bluephase G2, Radii Plus mostrou irradiância semelhante na região anterior e posterior e ambos receberam irradiância maior que 500 mW / cm2. Seis LCUs apresentaram menor irradiância que a recomendada (500mW / cm2) quando usado na região posterior, KON-LUX, Altlux II, Biolux Standard, TL-01, Optilux 501, DX Turbo LED 1200 e duas LCUs quando foram usadas na região anterior KON-LUX e Altlux II. O Bluephase G2  e Optilight Max forneceram a maior potência e o KON-LUX, o Altlux II eo Biolux Standard mostraram as menores potências. O espectro das LCUs de pico único foi muito variável e das multi-picos emitiram espectro semelhante para ambos os sensores. O design, a potencia radiante, a irradiância e o tipo de LCUs são fatores que os clínicos e pesquisadores precisam ter domínio quando necessitam fotoativar materiais resinosos.Palavras-chave: Fontes de Luz. Potência. Irradiância. Espectro de Emissão no Simulador de Paciente de MARC.

Efeito da Aplicação de Plasma na Adesão de Cimentos Resinosos à Blocos de Resinas CAD/CAM

Este estudo investigou o efeito da aplicação de plasma de argônio na resistência de união por cisalhamento (RUC) de dois cimentos resinosos a 3 resinas híbridas para CAD/CAM (Enamic, Cerasmart e Lava Ultimate) e uma resina composta indireta (Epricord – controle). Os materiais restauradores indiretos foram tratados (1) de acordo com instruções do fabricante (2) plasma de argônio (30s) e (3) plasma de argônio + adesivo ou silano. Em seguida, moldes de silicone foram posicionados na superfície tratada dos materiais e os cimentos resinosos (Panavia V5/PV5 ou RelyX Ultimate/RXU) foram inseridos no orifício do molde, obtendo-se cilindros dos cimen-tos (1,5 mm diâmetro e 1,0 mm altura) após fotoativação (n10). As amostras foram armazenadas em água destilada por 24 h e testadas em máquina de ensaio. Dados de RUC foram analisados por ANOVA 3-fatores e teste de Tukey (5%). A RUC do PV5 e RXU ao Lava Ultimate tratado com plasma e plasma + adesivo não mostrou diferença significativa quando comparado ao controle. Para os demais materiais, o tratamento como sugere o fabricante produziu maiores RCUs com o PV5. O RXU aplicado no Enamic com o uso do plasma não mostrou diferença estatística em re-lação ao controle. Para o Cerasmart e Epricord, a aplicação do plasma + adesivo também não diferiu do controle. Em geral, o RXU resultou em maior RUC que o PV5. A RUC dos cimentos resinosos aos materiais restauradores indiretos seguindo as instruções do fabricante produziu os melhores resultados, entretanto o uso do plasma pode ser uma alternativa, dependendo do material e do cimento resinoso.Palavras-chave: Resinas Compostas. Resistência ao Cisalhamento. Plasma.

Avaliação da Irradiância e Potência de Aparelhos Fotoativadores com Diferentes Instrumentos Clínicos e Laboratoriais

Os objetivos deste estudo foram mensurar e comparar a irradiância e a potência de quatro aparelhos fotoativadores (AFA) utilizando diferentes tipos de equipamentos. Os AFA usados foram: Elipar S-10, Elipar DeepCure-S, Valo e Bluephase Style. Os instrumentos medidores utilizados na avaliação da irradiância (mW/cm2) eram analógicos (Henry Schein, Spring, Demetron 100A, Demetron 100B e Demetron 200), digitais (Bluephase, Bluephase II, Coltolux, CureRite e Hilux) e de laboratório (Thermopile e Esfera integradora). Para a avaliação da potência (mW) foram utilizados os dois equipamentos de laboratório e o Bluephase II. Para avaliação da irradiância e potência, os AFA foram acionados por 20 seg (n 5). Os dados de irradiância e potência foram analisados pela análise de variância 1 fator e Student-Newman-Keuls teste. A irradiância mensurada pelo Coltolux, CureRite e Hilux foi maior que todos os demais equipamentos para o Elipar S-10. Para o Elipar DeepCure-S, Valo e Bluephase Style, todos os medidores analógicos mensuraram menor irradiância que os digitais e laboratoriais. Os equipamentos de laboratório apresentaram valores    de irradiância sem diferença estatística para o Valo,  que não foi observado para os demais AFA.  Na avaliação da potência, os    três equipamentos medidores sempre mostraram resultados diferentes, independente do AFA testado. Os resultados sugerem que a maioria dos medidores regularmente utilizados pelos dentistas (analógicos e digitais) apresentam ampla variação nos resultados e geralmente inferiores aos equipamentos usados em laboratório. Palavras-chave: Polimerização. Luz. Potência.

Effect of Sonic Resin Composite Delivery on Void Formation Assessed by Micro-computed Tomography

OBJECTIVES

The aim of this study was to quantify the internal void volume formation in commercially available, resin composites inserted using conventional or sonic insertion methods, and analyzed using three-dimensional (3D) micro-computed tomography (μCT).

METHODS AND MATERIALS

Four resin composites were evaluated: one conventional (Herculite, Ultra, Kerr Corporation, Orange, CA, USA), one flowable bulk fill (SureFil SDR Flow, Dentsply International, York, PA, USA), and two packable bulk fill (SonicFill, Kerr Corporation, and Tetric EvoCeram Bulk Fill, Ivoclar Vivadent Inc, Schaan, Liechtenstein). Eight groups were evaluated according to each resin composite type and insertion method (conventional or sonic; n=5). Forty ABS 3D-printed cylindrical molds, 5.0 mm in diameter and 4.0 mm in depth, were fabricated. For the conventional resin composite, the mold was filled incrementally (two layers), while for bulk-fill resin composites, insertion was performed in a single increment. The sonic insertion method was performed using a specific handpiece (SonicFill Handpiece, Kerr Corporation). Resin composites were light cured using a multipeak light-emitting diode light-curing unit (VALO, Ultradent Products Inc, South Jordan, UT, USA) in its regular mode. Samples were evaluated by μCT, and data were imported into software (Amira, version 5.5.2, VSG, Burlington, MA, USA) for 3D reconstruction, from which the percentage of void volume was calculated. Data were analyzed using two-way analysis of variance and Tukey post hoc test at a preset alpha of 0.05.

RESULTS

The conventional insertion method resulted in reduced porosity, compared with sonic insertion, for SureFil SDR Flow and Tetric EvoCeram bulk fill. The sonic insertion method did not demonstrate any influence on void formation for Herculite Ultra or SonicFill.

CONCLUSION

Results suggest that the sonic insertion method might increase void formation during resin composite delivery, depending on restorative material brand.

Characterization of Inorganic Filler Content, Mechanical Properties, and Light Transmission of Bulk-fill Resin Composites

OBJECTIVES

The aims of this study were to characterize inorganic content (IC), light transmission (LT), biaxial flexural strength (BFS), and flexural modulus (FM) of one conventional (layered) and four bulk-fill composites at different depths.

METHODS

Bulk-fill composites tested were Surefil SDR flow (SDR), Filtek Bulk Fill (FBF), Tetric EvoCeram Bulk Fill (TEC), and EverX Posterior (EXP). Herculite Classic (HER) was used as a control. Energy dispersive x-ray analysis and scanning electron microscopy were used to characterize filler particle composition and morphology. The LT through different composite thicknesses (1, 2, 3, and 4 mm) was measured using a laboratory-grade spectral radiometer system (n=5). For the BFS and FM tests, sets of eight stacked composite discs (0.5-mm thick) were prepared simulating bulk filling of a 4-mm-thick increment (n=8).

RESULTS

SDR demonstrated larger, irregular particles than those observed in TEC or HER. Filler particles in FBF were spherical, while those in EXP were composed of fiberglass strands. The LT decreased with increased composite thickness for all materials. Bulk-fill composites allowed higher LT than the HER. Furthermore, HER proved to be the unique material, having lower BFS values at deeper regions. SDR, FBF, and TEC bulk-fill composites presented reduced FM with increasing composite depth.

CONCLUSIONS

The bulk-fill composites investigated exhibited higher LT, independent of different filler content and characteristics. Although an increase in composite thickness reduced LT, the BFS of bulk-fill composites at deeper layers was not compromised.

Effect of Adhesive Restoration and Bleaching Technique on the Concentration of Hydrogen Peroxide In the Pulp Chamber

This study aimed to quantify the concentration of hydrogen peroxide into the pulp chamber in the presence or absence of adhesive enamel restorations and to analyze the resin-dentin interface of bleached groups. Bovine incisors (120) were randomly divided into three groups according to enamel treatment (n=40 each): (1) enamel without restoration (control); (2) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a silorane-based (SB) system; or (3) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a dimethacrylate-based (DB) system. Restorations were thermocycled, and all groups were submitted to one application of 35% hydrogen peroxide (HP) agent for 45 minutes and subjected to four light activation methods (n=10 each): without light, light-emitting diode (LED), LED/diode laser, or halogen light. Acetate buffer solution was placed into the pulp chamber before bleaching, and this solution was collected to spectrophotometrically determine the concentration of HP that reached the pulp chamber after bleaching. Rhodamine B was added to the HP agent and applied on additional enamel samples of each group for 24 hours. Samples were sectioned mesiodistally, and the bleaching agent was traced using confocal microscopy. According to two-way analysis of variance and Tukey test (α=0.05), the HP concentration in the pulp chamber of the control group was significantly lower than that of the SB group (p&lt;0.05), regardless of light activation. No differences were observed between DB and SB groups and between control and DB groups, except for the DB halogen light activated group, which exhibited higher HP intrapulpal concentration (p&lt;0.05). Confocal microscopy exhibited HP diffusion through the interface of the SB and DB restored groups as well as enamel prisms in the control group. The SB restorative system increased the HP diffusion into the pulp chamber, but HP was able to diffuse even in the absence of enamel restorations.

Microcomputed Tomography Evaluation of Polymerization Shrinkage of Class I Flowable Resin Composite Restorations

The present study aimed to characterize the pattern and volume of polymerization shrinkage of flowable resin composites, including one conventional, two bulk fill, and one self-adhesive. Standardized class I preparations (2.5 mm depth × 4 mm length × 4 mm wide) were performed in 24 caries-free human third molars that were randomly divided in four groups, according to the resin composite and adhesive system used: group 1 = Permaflo + Peak Universal Bond (PP); group 2 = Filtek Bulk Fill + Scotchbond Universal (FS); group 3 = Surefil SDR + XP Bond (SX); and group 4 = Vertise flow self-adhering (VE) (n=6). Each tooth was scanned three times using a microcomputed tomography (μCT) apparatus. The first scan was done after the cavity preparation, the second after cavity filling with the flowable resin composite before curing, and the third after it was cured. The μCT images were imported into three-dimensional rendering software, and volumetric polymerization shrinkage percentage was calculated for each sample. Data were submitted to one-way analysis of variance and post hoc comparisons. No significant difference was observed among PP, FS, and VE. SX bulk fill resin composite presented the lowest values of volumetric shrinkage. Shrinkage was mostly observed along the occlusal surface and part of the pulpal floor. In conclusion, polymerization shrinkage outcomes in a 2.5-mm deep class I cavity were material dependent, although most materials did not differ. The location of shrinkage was mainly at the occlusal surface.

Effect of Storage Time on Bond Strength Performance of Multimode Adhesives to Indirect Resin Composite and Lithium Disilicate Glass Ceramic

Purpose: To investigate the bond strength performance of multimode adhesives (MMAs) to indirect resin composite and lithium disilicate glass ceramic after 24 hours or one year of water storage.

Methods and Materials: Thirty flat and polished plates of indirect resin composite (Epricord) and thirty lithium disilicate glass ceramic plates (IPS e.max Press) were prepared. Surfaces were pretreated using sandblasting (indirect resin composite) or hydrofluoric acid (glass-based ceramic). Specimens were bonded with one of two MMAs (Scotchbond Universal [SBU] or All-Bond Universal [ABU]) or ceramic primer and hydrophobic bonding (RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Bond) as a control (n=10). Resin cement cylinders (0.75 mm in diameter × 0.5 mm in height) were bonded to both substrate surfaces using the respective adhesives. After 24 hours or one year of water storage, bonding performance was measured by microshear bond strength (MSBS) testing. Results were analyzed using three-way ANOVA with Bonferroni post hoc tests (α=0.05).

Results: For indirect resin composite, significantly higher MSBS values were found for ABU after 24 hours (ABU &gt; SBU = control); however, no significant difference among the adhesives was observed after one year (p&gt;0.05). For glass-based ceramic, significantly different bond strengths were observed among the adhesives after 24 hours (control = ABU &gt; SBU) and one year (control &gt; SBU = ABU; p&lt;0.05).

Conclusions: Both MMAs tested can be considered effective alternatives for bonding to sandblasted indirect resin composite after aging, as they showed similar bond performance to that of the control group. However, separate bottles of silane bonding resin showed higher MSBS values and more durable bonding for etched glass–based ceramic.