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SUMMARY Objectives: To determine the ability of dental professionals to deliver a radiant exposure of at least six J/cm2 in 10 seconds to simulated restorations. Methods and Materials: The study initially examined 113 light-emitting-diode (LED) light polymerization units (LPUs) used in dental offices to determine if they could deliver at least 6 J/cm2 radiant exposure (RE) in 10s. This assessment was completed by using a laboratory-grade light measuring device (checkMARC, BlueLight Analytics, Halifax, NS, Canada). The participating dental professionals whose LPUs could deliver 6 J/cm2 then used their own LPU to light-cure simulated anterior and posterior restorations in the MARC Patient Simulator (BlueLight Analytics). They then received specific instructions and were retested using the same LPUs. Data were statistically analyzed with a series of one-way analysis of variance (ANOVA), two-way ANOVA, paired-samples t-tests, Fisher post hoc multiple comparison tests, and McNemar tests with a preset alpha of 0.05 (SPSS Inc). Results: Ten (8.8%) LPUs could not deliver the required RE to the checkMARC in 10s and were eliminated from the study. For the anterior restoration, most dental practitioners (87.3%) could deliver at least 6 J/cm2 before instructions. After receiving additional light-curing instructions, only two (1.9%) participants were unable to deliver 6 J/cm2 to the anterior location. At the posterior location, only 55.3% (57) participants could deliver at least 6 J/cm2 before the instructions. After receiving these instructions, an additional 32 participants delivered at least 6 J/cm2. Overall, after receiving instructions on how to use the LPU correctly, the participants improved the amount of RE they delivered to anterior and posterior restorations by 22.5% and 30%, respectively. Conclusion: This study revealed that at the baseline, 44.7% of participating dental professionals failed to deliver 6 J/cm2 in 10s to the posterior simulated restoration when using their own LPU.

Background: Worldwide, chronic obstructive pulmonary disease (COPD) is in the spotlight because of its morbidity, mortality and high prevalence. In Egypt is highlighted as a major public health problem. The aim of the present study was to evaluate the impact of an educational program on knowledge, practice, and self-efficacy of patients with stable chronic obstructive pulmonary disease. Quasi- experimental research design was utilized in this study. The sample was consisted of all available patients with stable COPD during the time of data collection. Four tools were used to collect data: first; Structured interview questionnaire which consisted ofsocio-demographic characteristics, and medical history. Second; the Bristol COPD Knowledge Questionnaire (BCKQ), third; Observational checklist which consisted of breathing exercises& inhaler use, and fourth; Self-Efficacy Scale for Patients with COPD. The result of the study concluded that there was a highly statistically significant difference in patients' total knowledge and practice pre and post program & pre and follow up program. Concerning total Self Efficacy there was no statistically significant difference between pre and post & pre and follow up scores, but there was a highly statistically significant difference between pre and post program regarding all self-efficacy issues except with weather ∕environment, while there was no statistically significant difference between pre and follow up program in all self-efficacy issues except in negative affect issues. The study concluded that after implementation of the educational program, remarkable improvements were occurred in knowledge, practice, and self-efficacy sub scores. The study recommended Continuous monitoring and evaluation of self-efficacy for patients to enhance disease management through establishing a rehabilitation program for patient to improve their self-efficacy. Promotion and enhancement of the self-care modalities to the patient; a strict written instruction with pictures about disease process, allowed foods , rest and physical activities and follow up should be continued after termination of educational program.

Background: Worldwide, chronic obstructive pulmonary disease (COPD) is in the spotlight because of its morbidity, mortality and high prevalence. In Egypt is highlighted as a major public health problem. The aim of the present study was to evaluate the impact of an educational program on knowledge, practice, and self-efficacy of patients with stable chronic obstructive pulmonary disease. Research Design Quasi- experimental research design was utilized in this study. Subject& Methods, the sample was consisted of all available patients with stable COPD during the time of data collection. Two tools were used to collect data: Structured interview sheet which consisted ofsocio-demographic characteristics, and medical history. and; Self-Efficacy Scale for Patients with COPD. The result of the study concluded that there was no statistically significant difference between pre and post & pre and follow up scores, but there was a highly statistically significant difference between pre and post program all self-efficacy factors except with weather ∕environment, while there was no statistically significant difference between pre and follow up program in all self-efficacy factors except in negative affect factor. Conclusion, the study concluded that after implementation of the educational program, remarkable improvements were occurred in knowledge, practice, and self-efficacy sub scores. Recommendation, the study recommended continuous monitoring and evaluation of self-efficacy for patients, to enhance disease management through establishing a rehabilitation program for patient, and to improve their self-efficacy. Promotion and enhancement of the self-care modalities to the patient; a strict written instruction with pictures about disease process, allowed foods , rest and physical activities and follow up should be continued after termination of educational program.

Objectives To evaluate the clinical performance and the effect of various patient and provider-related factors on the longevity of chairside monolithic posterior lithium disilicate glass-ceramic (LDGC) computer-aided design (CAD)-computer-aided manufacturing (CAM) crowns provided by predoctoral students. Materials and methods A sample of posterior LDGC CAD-CAM crowns was evaluated. Crown preparations were milled chairside using the CEREC Omnicam system and cemented with Rely-X Unicem or Calibra Universal resin cements. Clinical assessment of the crowns and supporting periodontal structures was performed using the modified California Dental Association (CDA) criteria. Intraoral photographs as well as radiographs were taken for further assessment by two evaluators. Kaplan-Meier survival analysis was performed. Results A total of 40 crowns were inserted in 32 patients and evaluated for 4 years. Three complications were observed (two-technical and one-biological). No chipping or fracture of crowns was observed. No significant association was found between age, sex, periodontal condition, tooth type, tooth vitality, cement type, and longevity. The 4-year cumulative survival and success rates were 95.0 and 92.3%, respectively. Conclusion Chairside LDGC CAD-CAM crowns exhibited a high survival rate after 4 years in function and were shown to be a viable and reliable treatment option for posterior teeth. Clinical significance The high survival rate of chairside CAD-CAM crowns observed in this study suggests the likelihood of predictable performance in the predoctoral setup.

To determine the extent of radiant exposure (RE) attenuation of three LED light-polymerization units (LPUs), and their beam-profile, at the bottom of the Class-2 slot, using MARC-PS.10 seconds RE was delivered to MARC-PS' anterior sensor by Bluephase-Style, Demi-Plus, and Deep-Cure-S. Two ivorine lower first-molars received Class-2 proximal box preparations: (3×2×4 mm and 4×4×4 mm) and were sectioned horizontally above the cementoenamel junction. Tofflemire matrix-retainer was placed around each tooth and secured with a low-fusing compound. Each LPU tested delivered 10 seconds RE to MARC-PS through proximal slots. Mean RE of three readings per group was obtained. Data were analyzed using Pearson correlation, mixed ANOVAs with a pre-set alpha of 0.05.RE attenuation ratio calculated from the baseline to 4× 4×4/3×2×4 Class-2 boxes were: 58.25/80.03 Bluephase-Style; 49.36/80.25 Demi-Plus; 32.8/77.43 Deep-Cure-S. A significant and strong correlation (r= 0.86, P0.001) between the reduction in aperture size and RE was found. The beam profile of LED-LPUs tested decreased RE values at the bottom of a proximal box. More than 80% RE value reduction from the baseline to the smallest Class-2 cavity 3×2×4 aperture was observed.Polymerization of resin-composites at the bottom of the Class-2 box is challenging due to the small aperture size, depth, and hard-to-reach location. Inadequate polymerization at the bottom of the Class-2 proximal box is a causative factor for secondary caries and, ultimately, restoration failure.

The use of ceramic materials and the computer-aided design/computer-aided manufacturing (CAD/CAM) technology for the fabrication of complete-coverage restorations has significantly increased in the last decade. The aim of this study was to evaluate the survival rate of anterior and posterior monolithic and bilayered lithium disilicate glass-ceramic (LDGC) CAD/CAM crowns, and to identify the types of complications associated with the main clinical outcomes reported in clinical trials. MEDLINE/PubMed, Embase, Scopus, Web of Science, Cochrane Library, and ClinicalTrials.gov were searched by 2 independent reviewers for clinical studies published between 2006 and 2019, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The electronic search was supplemented by a hand search. Quality assessment for the included studies was performed. Qualitative and quantitative data was extracted from each study. Out of 219 studies, 6 studies that evaluated LDGC CAD/CAM crowns were identified and used for data extraction. The included studies had 154 participants, who received 204 crowns. The shortto medium-term survival and success rates were high. Biological complications occurred more frequently than technical complications. No esthetic complications were reported. This review indicated that the medium-term survival rate of LDGC CAD/CAM crowns was high. Further multicenter studies with longer follow-ups and larger sample sizes are needed in order to augment the data already in existence.

New glass-ceramic restorative materials have been developed over the last few years, with enhanced strength characteristics along with desirable optical properties that make them ideal for the fabrication of esthetic crowns and veneers. The purpose of this paper was to provide an overview of the current state of the art of porcelain veneers as a viable option for the esthetic treatment of anterior teeth, and to illustrate the potential of the newly-developed glass-ceramics. Some historical background about the development of the porcelain veneer concept is provided. A list of indications and contraindications for porcelain veneers is followed by their preparation designs, with emphasis on the importance of maintaining the preparation boundaries within the enamel. Impression-taking procedures, provisional restoration fabrication, the choice of porcelain materials and their intaglio surface treatment are all discussed. A case where veneers made with a lithium-disilicate glass-ceramic were used to improve the appearance of maxillary anterior teeth is included. Several studies reporting on the longevity of porcelain veneers up to 12 years are discussed.

© 2018 by Wroclaw Medical University and Polish Dental Society. Background. All-ceramic restorations have become popular and the trend is ongoing. However, the incidence of chipping within the veneering layer has been a commonly reported failure in clinical practice. Objectives. The aim of this in vitro study was to evaluate the effect of ceramic crown design (monolithic vs bi-layered) and material on the chipping resistance of molar crowns submitted to compressive cyclic loading. Material and methods. Fifty identical epoxy resin replicas of a mandibular first molar with crown preparation were divided into 5 groups (n = 10) as follows: the MLD group – monolithic CAD/CAM lithium-disilicate glass-ceramic (LDGC) crowns; 30 zirconia cores were veneered with either feldspathic porcelain by hand-lay-ering technique (ZHL) or by heat-pressing technique (ZVP), or with milled LDGC veneers and subsequently fused to the cores (ZLD); 10 porcelain-fused-to-metal (PFM) crowns acted as a control group. All crowns were cemented using Panavia® F2.0 resin cement (Kuraray Dental, Tokyo, Japan). After storage in water at 37°C for 1 week, the specimens were subjected to compressive cyclic loading at the mesiobuccal cusp which was tilted at 30°. A load cycle of 50–450 N was used and specimens were maintained in an aqueous environment throughout 500,000 cycles in a universal testing machine (Instron, Norwood, USA). The data was statistically analyzed at 5% significant level with Fisher’s exact test and Kaplan-Meier survival analysis. Results. Significant differences in survival rates of the specimens used in the groups (p < 0.001) were found. Specimens of the PFM, ZHL and ZVP groups underwent failures at different stages of the 500,000 fatigue cycles, while specimens of the MLD and ZLD groups survived the entire fatigue test. ZHL and ZVP crowns had the worst chipping-resistance, while PFM crowns performed slightly better. The Kaplan-Meier test revealed significantly higher survival rates for the MLD and ZLD specimens compared to the other 3 groups. Conclusions. The use of LDGC as a monolithic molar crown and as a veneer over a zirconia core resulted in superior resistance to cuspal chipping.

(1) Background: The aim of this study is to evaluate the hardness of resin cements polymerized through ceramic disks under different process factors (ceramic type and thickness, light-polymerization units and polymerization time), (2) Method: Three types of ceramic blocks were used (IPS e.max CAD, Celtra Duo, VITABLOCS). Ceramic disks measuring 0.5 mm, 1.0 mm and 1.5 mm were cut from commercial blocks. Two resin cements (Rely X Veneer and Variolink Esthetic) were polymerized through the ceramic specimens using distinct light-polymerization units (Deep-cure, Blue-phase) and time intervals (10 and 20 s). Hardness of cement specimens was measured using microhardness tester with a Knoop indenter. Data were statistically analyzed using factorial ANOVA (α = 5%), (3) Results: Mean microhardness of Rely X Veneer cement was significantly higher than that of Variolink Esthetic. Deep-cure resulted in higher mean microhardness values compared to Blue-phase at 0.5- and 1-mm specimen thicknesses. Moreover, a direct correlation was found between polymerization time and hardness of resin cement, (4) Conclusions: Surface hardness was affected by resin cement type and ceramic thickness, and not affected by ceramic types, within evaluated conditions. Increasing light-polymerization time significantly increased the hardness of the cement.

STATEMENT OF PROBLEM Monitoring performance of glass-ceramic based indirect restorations using radiographic imaging might be difficult due to their low radiopacity. Therefore, materials used for their cementation must possess adequate radiopacity. PURPOSE This study determined radiopacity of a group of resin-cements used for adhesive-cementation of glass-ceramic-based restorations using digital radiography. METHODS Two specimens were prepared from a group of resin cements (VariolinkII-opaque, VariolinkII-opaque (base), VariolinkII-Transparent, VariolinkII-Transparent (base), Nexus, RelyX Unicem, RelyX ultimate, Duolink, Monocem and Resinomer) and longitudinal sections of same thickness were obtained from molar and premolar. Specimens were assigned to two groups one had molar section with 10 specimens whereas other had premolar with remaining 10 specimens. Each group was placed on digital radiograph sensor (Schick CDR, size 2) together with aluminum step-wedge. Sensor was exposed to X-ray using standard technique. Two images were obtained for each group. Pixel measurements were made using NIH Image-J software. Mean pixel measurements were converted into aluminum thickness equivalents. Data were statistically-analyzed using one-way ANOVA and Tukey's tests. RESULTS ANOVA revealed significant difference in mean pixel values among cements (p < 0.001). VariolinkII-opaque showed highest mean aluminum equivalent (4.6 mm Al/1 mm) followed by VariolinkII-opaque-Base (4.5 mm Al/1 mm), VariolinkII-transparent (4.45 mm Al/1 mm), VariolinkII-transparent-Base (4.45 mm Al/1 mm), Nexus (2.95 mm Al/1 mm), Duolink (2.7 mm Al/1 mm), RelyX Unicem (2.2 mm Al/1 mm) and finally RelyX ultimate (2 mm Al/1 mm). All cements had mean radiopacity values higher than that of enamel whereas Monocem (1.25 mm Al/1 mm) and Resinomer (1.2 mm Al/1 mm) had means between those of enamel and dentin. CONCLUSIONS All tested resin-cements showed radiopacity values higher than that of dentin which is adequate for diagnostic purposes according to ISO recommendation. CLINICAL SIGNIFICANCE The use of resin cement with adequate radiopacity for adhesive cementation of glass-ceramic based restorations enables their radiographic monitoring. (J Esthet Restor Dent 29:215-221, 2017).

The aims of this study were to determine the convergence angles of posterior teeth prepared by dental students at the University of Toronto for lithium disilicate glass-ceramic (LDGC) CAD/CAM crowns and to investigate their effect on loss of retention rate. A total of 280 preparations for posterior monolithic LDGC CAD/CAM crowns were performed on 270 patients (169 women and 101 men). Crowns were cemented with RelyX Unicem and Calibra Universal resin cements. Mesial, distal, and angle of convergence were measured on the bitewing radiographs. Cemented crowns were followed for up to six years. Data were analyzed for tooth type and location and for operator experience. The results showed the majority of convergence angles were greater than the recommended guidelines but fell within a clinically acceptable range (20 to 24 degrees). However, angles of convergence for mandibular molar preparations were highest (28.06±5.50 degrees), while maxillary premolars exhibited the lowest values (24.72±6.59 degrees). No significant difference was found between the results of dental students and foreign-trained dentists. Over a six-year observation period, only two crowns lost retention. The findings of this study indicated that ideal taper angles were impractical and difficult to achieve in clinical education settings.

Statement of problem The clinical success of monolithic lithium disilicate glass-ceramic (LDGC) crowns manufactured with computer-aided design and computer-aided manufacturing (CAD-CAM) technology provided by predoctoral students has not been fully investigated. Purpose The purpose of this retrospective clinical study was to evaluate the performance of laboratory-fabricated monolithic posterior LDGC CAD-CAM crowns provided by predoctoral students at the University of Toronto. Specific patient- and provider-related factors were also investigated. Material and methods A sample of posterior LDGC CAD-CAM crowns (IPS e.max) provided by predoctoral students was evaluated. Crown preparations were made according to specific criteria, and crowns were milled in an in-house laboratory by using the CEREC Bluecam system. The crowns were cemented with Rely-X Unicem (3M ESPE) and Calibra Universal (Dentsply Sirona) resin cements. Clinical assessments of the crowns and supporting periodontal structures were performed following the modified California Dental Association (CDA) criteria. Intraoral photographs and periapical and bitewing radiographs were obtained for further assessment by 2 evaluators. Descriptive statistics, McNemar, t test, log rank (Mantel-Cox) tests, Pearson chi-squared tests, simple logistic regression, odds ratios, and Kaplan Meier survival analyses were performed (α=.05). Results A total of 189 patients receiving 210 crowns (108 premolar and 102 molar) were examined with a follow-up period of up to 6 years. Altogether, 28 complications were observed (12 technical, 11 biological, and 5 esthetic). No significant association was found between patient age, sex, periodontal condition, tooth type, tooth vitality, cement type, and crown longevity. However, significantly lower survival and success rates were found for mandibular crowns than for maxillary crowns (P=.029). The provider’s experience had no significant effect on the clinical performance of LDGC CAD-CAM crowns. The 6-year cumulative survival rate was 93.0%, and the success rate was 86.4%. Conclusions The ease of use of the CAD-CAM system and clinical performance of LDGC suggest that this technology should be used in the dental school setting by predoctoral students.

Background Bulk-fill composites were developed to simplify composite placement and minimize polymerization shrinkage stresses, which can improve gingival marginal adaptation in deep class II cavities. Objectives The objective of this study was to compare the gingival microleakage of class II cavities restored with bulk-fill composites to that of incrementally restored ones with a conventional composite at 2 storage periods. Material and methods Forty freshly extracted intact molars were employed. Two standardized class II slot cavities, 3-millimeter-wide buccolingually, with the gingival floor 0.5 mm below the cementoenamel junction (CEJ) and the axial wall depth of 1.3 mm were prepared in each tooth (80 cavity preparations). The prepared teeth were divided equally into 3 bulk-fill groups (Tetric EvoCeram® Bulk Fill, X-tra Fil® and QuiXX®) and 1 control group (TPH Spectra® HV). Each group was subdivided into 2 equal subgroups (n = 10) according to the storage period in distilled water (24 h and 6 months). The Adper® Single Bond Plus adhesive was used with all the restorative materials. The cavities in the experimental groups were restored with 4-millimeter bulk-fill composites in 1 increment, while the cavities in the control group were restored with 2 increments of the thickness of 2 mm. The polymerization light was applied from the occlusal surfaces. The teeth were then immersed in 2% procion red dye solution, sectioned and examined under a stereomicroscope to determine the extent of dye penetration. The data was statistically analyzed using the Kruskal-Wallis test and the Mann-Whitney U test. Results The Kruskal-Wallis test revealed no significant differences in the mean microleakage scores among all the groups after 24-hour and 6-month storage (p = 0.945 and p = 0.928, respectively). The Mann-Whitney U test revealed an increase in the mean microleakage scores in all the groups after 6-month storage; however, the scores were not significantly different from the means obtained after 24 h (p = 0.259 for Tetric EvoCeram Bulk Fill; p = 0.205 for X-tra Fil; p = 0.166 for QuiXX; p = 0.155 for TPH Spectra HV). Conclusions Gingival microleakage of bulk-fill composites in class II cavities was not significantly different from that of incrementally restored ones with a conventional composite. The increase in the mean gingival microleakage of the specimens stored for 6 months was not statistically significantly different in comparison to the values obtained after the 24-hour storage period for each composite.

Objective This in-vitro study determined plane-strain fracture toughness (KIC) of five different chairside CAD/CAM materials used for crown fabrication, following alternative innovative loading approach of compact tension test specimens. Methods Rectangular-shaped specimens were cut from CAD/CAM blocks (n = 10): Vita Mark II (Vident) (VMII); Lava-Ultimate (3M/ESPE) (LU); Vita Enamic (Vident) (VE); IPS e.max CAD (Ivoclar Vivadent); crystallized and un-crystallized (E-max and E-max-U, respectively); and Celtra Duo (Dentsply) fired and unfired (CD and CD-U, respectively). Specimens were notched with thin diamond disk prior to testing. Instead of applying tensile loading through drilled holes, a specially-made wedge-shaped steel loading-bar was used to apply compressive load at the notch area in Instron universal testing machine. The bar engaged the top ¼ of the notch before compressive load was applied at a cross-head speed of 0.5 mm/min. Fracture load was recorded and KIC calculated. Data was statistically-analyzed with one-way ANOVA at 95% confidence level and Tukey's tests. Results Means and SDs of KIC in MPa m1/2 for VMII, LU, VE, E-max, E-max-U, CD and CD-U were: 0.73 (0.13), 0.85 (0.21), 1.02 (0.19), 1.88 (0.62), 0.81 (0.25), 2.65 (0.32) and 1.01 (0.15), respectively. ANOVA revealed significant difference among the groups (p Significance Mean KIC values of the tested materials varied considerably, however, none of them reached mean KIC of dentin (3.08 MPa m1/2) previously reported. For E-max and CD, specimens firing significantly increased mean KIC. The modified test arrangement was found to be easy to follow and simplified specimen preparation process.

During a fiber post cementation, bonding failure often occurs at the junction between the fiber-post and resin-cement. Because this failure requires better characterization, we evaluated if different post surface treatment can affect the bond strength of urethane dimethacrylate (UDMA) fiber-posts with resin-cements. Three groups were created: G1: no treatment/silane; G2: ethyl alcohol (96° GL)/silane; G3: 24% H2O2/silane and further divided into four subgroups: I-Unicem/3MESPE; II-BisCem/Bisco; III-Panavia SA/Kuraray and IV-DuoLink/Bisco. Blocks of cured resin cements and posts placed in the center were serially cut into bar-shaped specimens and loaded into a micro tensile testing machine. ANOVA indicated no significant differences among post surface treatments (p>0.05), however, significant within the resin cements (p

Purpose: This study determined the radiopacity of a group of computer-aided design/ computer-assisted manufacture blocks using digital radiography and pixel monitoring. Materials and Methods: Specimens 2.0 ± 0.05-mm thick were cut from nine different blocks. Longitudinal sections of the same thickness were obtained from molar and premolar. Specimens were assigned to one of two groups, and each group was placed on a digital radiograph sensor together with an aluminum step wedge. Following standardized technique, the sensor was exposed and two images were obtained from each group. Images were analyzed using ImageJ software to determine the number of pixels at five different locations for each specimen. Means and standard deviations were calculated and the data statistically analyzed. Radiopacity values were expressed as equivalent of aluminum thickness. Results: Analysis of variance revealed significant difference in mean pixels among the blocks (P < .001). Conclusion: The majority of blocks had radiopacity values that were higher than that of dentin.

Monitoring performance of glass-ceramic based indirect restorations using radiographic imaging might be difficult due to their low radiopacity. Therefore, materials used for their cementation must possess adequate radiopacity.This study determined radiopacity of a group of resin-cements used for adhesive-cementation of glass-ceramic-based restorations using digital radiography.Two specimens were prepared from a group of resin cements (VariolinkII-opaque, VariolinkII-opaque (base), VariolinkII-Transparent, VariolinkII-Transparent (base), Nexus, RelyX Unicem, RelyX ultimate, Duolink, Monocem and Resinomer) and longitudinal sections of same thickness were obtained from molar and premolar. Specimens were assigned to two groups one had molar section with 10 specimens whereas other had premolar with remaining 10 specimens. Each group was placed on digital radiograph sensor (Schick CDR, size 2) together with aluminum step-wedge. Sensor was exposed to X-ray using standard technique. Two images were obtained for each group. Pixel measurements were made using NIH Image-J software. Mean pixel measurements were converted into aluminum thickness equivalents. Data were statistically-analyzed using one-way ANOVA and Tukey's tests.ANOVA revealed significant difference in mean pixel values among cements (p0.001). VariolinkII-opaque showed highest mean aluminum equivalent (4.6 mm Al/1 mm) followed by VariolinkII-opaque-Base (4.5 mm Al/1 mm), VariolinkII-transparent (4.45 mm Al/1 mm), VariolinkII-transparent-Base (4.45 mm Al/1 mm), Nexus (2.95 mm Al/1 mm), Duolink (2.7 mm Al/1 mm), RelyX Unicem (2.2 mm Al/1 mm) and finally RelyX ultimate (2 mm Al/1 mm). All cements had mean radiopacity values higher than that of enamel whereas Monocem (1.25 mm Al/1 mm) and Resinomer (1.2 mm Al/1 mm) had means between those of enamel and dentin.All tested resin-cements showed radiopacity values higher than that of dentin which is adequate for diagnostic purposes according to ISO recommendation.The use of resin cement with adequate radiopacity for adhesive cementation of glass-ceramic based restorations enables their radiographic monitoring. (J Esthet Restor Dent 29:215-221, 2017).

Purpose: This study evaluated the influence of surface treatments on the microtensile bond strength between a glass fiber post surface and resin cements. Methods: Forth-five posts (Reforpost, Angelus, Londrina, PR- Brazil) were assigned to three groups with different surface treatment: Group 1: No treatment and silane application only (G1); Group 2: immersion in 96% ethyl alcohol for 10 minutes followed by silane application (G2); Group 3: immersion in 24% H2O2 for 10 minutes followed by silane application (G3). Each group was divided into 3 subgroups according to the resin cement used: UniCem/3MESPE (UN); BisCem/Bisco (BC); and Panavia F/Kuraray (PN). Posts were placed in a square-shaped matrix, in which it was held in place by the resin cement and subsequently photo-cured. Blocks were obtained, serially cut into sticks and then loaded onto a micro-tensile testing machine. Results: ANOVA indicated significant differences among surface treatments (p 0.05). Group G1 had lower bond strength values (p

Objective This in vitro study compared cuspal deflection of premolars restored with three bulk-fill composite resins to that of incrementally-restored ones with a low-shrinkage silorane-based restorative material. Materials and Methods Forty freshly-extracted intact human upper premolars were used. Reference points at buccal and palatal cusp tips were acid-etched and composite rods were horizontally bonded to them (TPH-Spectra-HV, Dentsply). Two acrylic resin guiding paths were made for each premolar to guide beaks of a digital micrometer used for cuspal deflection measurements. Standardized MOD cavities, 3 mm wide bucco-lingually and 3.5 mm deep, were prepared on each premolar. Prepared teeth were then equally divided into four groups (n = 10) and each group was assigned to one of four composite resin (QuiXX, Dentsply; X-tra fil, Voco; Tetric EvoCeram Bulk Fill, Ivoclar Vivadent; low-shrinkage Filtek LS, 3M/ESPE). Adper Single Bond-Plus, 3M/ESPE was used with all bulk-fill restoratives. LS-System Adhesive, 3M/ESPE was used with Filtek LS. For each prepared premolar, cuspal deflection was measured in microns as the difference between two readings between reference points before and after restoration completion. Means and SDs were calculated and data statistically-analyzed using One-way ANOVA and Tukey's test. Results Filtek LS showed the lowest mean cuspal deflection value 6.4(0.84)μm followed by Tetric EvoCeram Bulk Fill 10.1(1.2) μm and X-tra fil 12.4(1.35)μm, while QuiXX showed the highest mean 13(1.05)μm. ANOVA indicated significant difference among mean values of groups (p

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:05:44Z No. of bitstreams: 1 S1516-14392012000400003.pdf: 5474891 bytes, checksum: 8bfb364b8adea5b5d12bd158b233aaaa (MD5) Made available in DSpace on 2013-08-22T19:05:44Z (GMT). No. of bitstreams: 1 S1516-14392012000400003.pdf: 5474891 bytes, checksum: 8bfb364b8adea5b5d12bd158b233aaaa (MD5) Previous issue date: 2012-08-01 Made available in DSpace on 2013-09-30T20:09:38Z (GMT). No. of bitstreams: 2 S1516-14392012000400003.pdf: 5474891 bytes, checksum: 8bfb364b8adea5b5d12bd158b233aaaa (MD5) S1516-14392012000400003.pdf.txt: 24250 bytes, checksum: 41d6190dbc237da624554124d1adf256 (MD5) Previous issue date: 2012-08-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:46:58Z No. of bitstreams: 2 S1516-14392012000400003.pdf: 5474891 bytes, checksum: 8bfb364b8adea5b5d12bd158b233aaaa (MD5) S1516-14392012000400003.pdf.txt: 24250 bytes, checksum: 41d6190dbc237da624554124d1adf256 (MD5) Made available in DSpace on 2014-05-20T13:46:58Z (GMT). No. of bitstreams: 2 S1516-14392012000400003.pdf: 5474891 bytes, checksum: 8bfb364b8adea5b5d12bd158b233aaaa (MD5) S1516-14392012000400003.pdf.txt: 24250 bytes, checksum: 41d6190dbc237da624554124d1adf256 (MD5) Previous issue date: 2012-08-01 This study evaluated the fracture resistance of teeth submitted to internal bleaching and restored with different non-metallic post. Eighty mandibular incisors were endodontically treated and randomly divided in 10 groups (n = 8): G1- restored with composite resin (CR), G2- CR + fiber-reinforced composite post (FRC, Everstick post, Sticktech) cemented with resin cement self-etch adhesive (RCS, Panavia F 2.0, Kuraray), G3- CR + FRC + self-adhesive resin cement (SRC, Breeze, Pentral Clinical), G4- CR+ glass fiber post (GF, Exacto Post, Angelus) + RCS, G5- CR + GF + SRC. The G6 to G10 were bleached with hydrogen peroxide (HP) and restored with the same restorative procedures used for G1 to G5, respectively. After 7 days storage in artificial saliva, the specimens were submitted to the compressive strength test (N) at 0.5 mm/min cross-head speed and the failure pattern was identified as either reparable (failure showed until 2 mm below the cement-enamel junction) or irreparable (the failure showed

Purpose: The aim of this study was to determine effect of compressive cyclic loading on fatigue resistance and microleakage of monolithic CAD/CAM molar ceramic and composite crowns. Materials and Methods: Thirty-two extracted molars were prepared to receive CEREC crowns according to manufacturer's guidelines using a special paralleling device (Parallel-A-Prep). Sixteen feldspathic ceramic crowns (VITABLOCS Mark II) (VMII) and 16 resin-composite crowns (Paradigm-MZ100 blocks) (PMZ) were milled using a CEREC-3D machine. Eight crowns of each group were cemented to their respective teeth using self-etching resin cement (Panavia-F-2.0) (PAN), and eight were cemented using self-adhesive resin cement (RelyX-Unicem-Clicker) (RXU). Following storage for 1 week in water, specimens were subjected to uniaxial compressive cyclic loading in an Instron testing machine at 12 Hz for 1,000,000 cycles. Load was applied at the central fossa, and the cycle range was 60–600 N. Specimens were then subjected to microleakage testing. Data were statistically analyzed using factorial ANOVA and Post Hoc (Tukey HSD) tests. Results: All composite crowns survived compressive cyclic loading without fracture, while three ceramic crowns from the subgroup cemented with RXU developed surface cracks at the center of occlusal surfaces, extending laterally. Microleakage scores of ceramic crowns cemented with PAN were significantly lower than those of the other three subgroups (p < 0.05). Conclusions: After 1,000,000 cycles of compressive cyclic loading, PMZ composite molar crowns were more fatigue-resistant than VMII ceramic crowns. Cement type had a significant effect on fatigue resistance of the ceramic crowns but not the composite ones. Microleakage scores of ceramic crowns cemented with PAN were significantly lower than those of the other subgroups (p < 0.05).

Background The authors investigated the postcementation sensitivity associated with self-adhesive resin cements used with fixed partial dentures (FPDs). Methods The authors recruited 20 patients who needed posterior porcelain-fused-to-metal FPDs and divided them randomly into three groups. They prepared 50 abutments, then cemented FPDs with one of two self-adhesive resin cements (Breeze Self-Adhesive Resin Cement, Pentron Clinical Technologies, Wallingford, Conn., and RelyX Unicem Self-Adhesive Universal Resin Cement, 3M ESPE, Seefeld, Germany) or an etch-and-rinse resin cement (RelyX ARC Adhesive Resin Cement, 3M ESPE, St. Paul, Minn.). The authors measured participants' tooth sensitivity to cold water, air blast and biting at 24 hours and at two, six and 12 weeks after FPD cementation by using a continuous visual analog scale (VAS). Data were analyzed statistically by means of the Mann-Whitney test. Results For cold tests, the highest VAS scores occurred 24 hours after cementation. The mean VAS scores associated with RelyX ARC were significantly higher than those associated with Breeze and RelyX Unicem ( P P > .05). With all cements, sensitivity to cold decreased significantly after two to six weeks; however, with RelyX ARC, VAS scores stayed above the 30 percent level even after 12 weeks. The biting sensitivity associated with RelyX ARC was significantly higher than that associated with Breeze and RelyX Unicem ( P Conclusions and Clinical Implications Breeze and RelyX Unicem were associated with significantly lower postoperative tooth sensitivity values than was RelyX ARC. With Breeze and RelyX Unicem, postoperative tooth sensitivity disappeared after two to six weeks; however, with RelyX ARC it remained even after 12 weeks. Clinicians may use self-adhesive resin cements, and benefit from their bonding potential, without fear of patients' developing tooth sensitivity.

This study determined the microleakage of Class II composite restorations lined with self-adhesive resin-cements as bonding agents.Forty-five caries-free extracted molars were sterilized, mounted in acrylic bases and divided into five equal groups according to the adhesive used: RXU (RelyX-Unicem, self-adhesive resin-cement, 3M ESPE), BRZ (Breeze, self-adhesive resin-cement, Pentron Clinical Technologies), MON (Monocem, self-adhesive resin-cement, Shofu), PAN (Panavia-F-2.0, resin-cement with self-etch primer, Kuraray) and SBMP (Scotchbond Multi-Purpose, total-etch three-step adhesive, 3M ESPE). Class II MOD cavities were prepared with gingival floors located on dentin at one side and on enamel on the other. The bonding agent SBMP, used according to the manufacturer's directions, or a thin layer of resin cement, was applied on all cavity walls and cavosurface margins. Filtek Z250 (3M ESPE) was used to restore cavities in all groups. The specimens were subjected to 1,000 thermocycles between 5 degrees C and 55 degrees C. All tooth surfaces were sealed with nail-varnish to within 1 mm from the restoration margins. The specimens were immersed in 2% fuchsine red solution for 24 hours at 37 degrees C. The teeth were then sectioned mesiodistally and dye penetration was assessed according to a five-point scale. Data were statistically analyzed with the Chi-square test (p0.05).Microleakage scores revealed that, on enamel margins, the SBMP group had significantly less microleakage than the RXU and BRZ groups, which, in turn, had significantly less microleakage than the MON and PAN groups; whereas on dentin margins, the RXU and BRZ groups had significantly less microleakage than the SBMP, MON and PAN groups.This in-vitro study showed that, when two self-adhesive resin-cements (RXUBRZ) were used as liners in Class II composite restorations, they resulted in low microleakage scores as compared to the two other cements at both the enamel and dentin cavosurface margins.

Purpose: Resistance of machined crowns to microleakage when cemented with new self-adhesive cements has not been fully investigated. This study evaluated microleakage of machined crowns milled from porcelain and composite blocks and bonded to teeth with self-adhesive and conventional resin cement. Materials and Methods: Thirty-two freshly extracted premolars of similar shape and size were sterilized and mounted in resin blocks. Teeth received standard crown preparations with 1-mm circumferential shoulder finish line, flat occlusal surface reduced by 2 mm, and ideal angle of convergence. Prepared teeth were divided into two equal groups and assigned to either porcelain (Vita Mark II, Vident) or composite (Paradigm MZ100, 3M ESPE) blocks for crown fabrication. Optical impressions were captured for each tooth with the intraoral camera of a CEREC 3D machine. Crowns were designed and milled from both materials. Each group was then subdivided into two subgroups (n = 8) according to cement used (self-adhesive resin cement, RelyX Unicem, 3M ESPE or resin cement with self-etching adhesive, Panavia F 2.0, Kuraray). Following seating, a 5-kg weight was applied on the occlusal surface of the crown for 5 minutes. Specimens were then stored in water at 37°C for 24 hours. Specimens were thermocycled for 3000 cycles between 5°C and 55°C, then coated with nail varnish and immersed in a 2.0% basic red fuchsine dye solution for 24 hours. Teeth were then rinsed and sectioned mesiodistally and assessed under magnification for microleakage. A five-point scale was used to score degree of microleakage. Data were statistically analyzed with 2-way ANOVA and Kruskal-Wallis nonparametric test. Results: Crown material had no significant effect on microleakage (p= 0.67); however, cement type had a significant effect (p < 0.0001), with Panavia F 2.0 resulting in lower microleakage scores than RelyX Unicem. Conclusions: Compared to the self-adhesive cement, the resin cement with separate primer/bonding agent resulted in significantly lower microleakage scores, irrespective of crown material.

Objectives: The purpose of this study was to determine color changes and surface roughness of composites when they were subjected to in-office bleaching.Methods: 12 discs 15 mm in diameter and 2 mm thick were prepared from two shades (A2 & A4) of two composites, Durafil VS (DF) and TPH3 (TPH). Specimens were polished and stored in distilled water for 24 hours at 37°C before being subjected to bleaching, staining, and re-bleaching. Each of the groups of specimens (DF-A2, DF-A4, TPH-A2 and TPH-A4) were subdivided into three subgroups (n=4) and bleached with Beyond, LumaWhite-Plus, and Opalescence-Boost. Specimens were then stained by immersing them in a coffee solution for 48 hours at 37°C, and then they were re-bleached. Colorimetric measurements were performed at baseline, after bleaching, after staining, and after rebleaching. Surface roughness was determined with environmental SEM before and after bleaching. Data were statistically-analyzed.Results: None of the bleaching systems notably changed the color of composites (delta-EConclusions: Three in-office bleaching agents had no significant color changes on two composites. DF showed more color change than TPH when immersed in coffee. Stained composites showed different degrees of whitening, with DF showing more response. Bleaching may adversely affect the surface texture of composites. Dentists should take into consideration that composite restorations may not respond to bleaching in the same way that natural teeth do. (Eur J Dent 2010;4:118-127)

To determine the effect of thickness of porcelain veneers constructed from CAD-CAM on their final color when two resin cements were used.Buccal surfaces of extracted sound human molars with shade 3M2 [verified using digital spectrophotometer (Vita Easyshade-Vident)] were reduced to expose flat enamel surfaces. CAD-CAM blocks (Vitablokcs Mark II) of the same shade were sectioned into three groups of 0.3, 0.5 and 0.7mm thickness. Each group was subdivided into two subgroups; one subgroup was cemented to enamel using an etch-and-rinse resin cement (Calibra/Prime and bond-NT, Dentsply) and the other was cemented to enamel using a self-etching resin cement (Panavia-F, Kuraray). The shade of the two resin cements was "light". Change in color (ΔE) between the selected shade (3M2) and the resulted shade was measured for each specimen using a digital spectrophotometer (Vita Easyshade-Vident). Means and SDs were calculated and data was statistically analyzed using ANOVA and post hoc tukey's.Change in color (ΔE) between the selected and the produced shade for the Calibra subgroups was 2.8 (0.3) for the 0.3mm, 1.67 (0.2) for the 0.5mm thick specimens and 1.26 (0.3) for the 0.7mm. Panavia F subgroups showed ΔE of 2 (0.4) for the 0.3mm, 1.13 (0.23) for the 0.5mm thick specimens and 1.21 (0.31) for the 0.7mm. The 0.7mm subgroups showed no significant difference in color change among the two cements (P.05), however, Calibra resulted in significantly higher change in color values for the 0.5mm thick specimens (P.05). In spite of the presence of significant difference for the Calibra 0.5mm thick subgroup, the color change was considered to be within the clinically acceptable range. The 0.3mm showed high significant difference for the two tested cements with the Panavia showing less change in color and Calibra showing clinically detectable change in color.Increasing porcelain veneer thickness from 0.5 to 0.7mm did not significantly affect the final color of cemented veneers. Whilst the color was significantly affected at the thickness of 0.3mm.

M-Wire (Sportswire LLC, Langley, OK) is reportedly created by altering alloy temperatures during the manufacturing process of GT series X instruments (Dentsply Tulsa Dental Specialties, Tulsa, OK). Currently, there are few published studies looking at torsional profiles of these instruments. The purpose of this study was to investigate the torsional profiles of new and used 20/0.06 GT series X (GTX) and GT (GT) instruments (Dentsply Tulsa Dental Specialties).Thirty instruments were allocated to one of eight groups and were used 2, 6, or 10 times in simulated canals or remained as unused controls. Testing of torque (TF) and angle at fracture (AF) were conducted in accordance with American National Standards Institute/American Dental Association (ANSI/ADA) specification No. 28. Data analyses were performed by using one- and two- way analysis of variance with honesty significance difference post hoc comparison with alpha = 0.05.Overall, there were significant differences in TF and AF among the experimental groups (p0.001). GTX instruments showed a significant initial increase in TF with two and six uses (p0.001) in contrast to the GT, which showed a linear reduction in TF with increased use (p0.004). Both GTX and GT instruments showed no statistical difference in AF of new instruments but did show a significant decrease in AF in all groups except the GT two-use group (p0.02).The GTX instruments had a higher resistance to torsional failure after use as compared with the GT.

The indirect adhesive procedures constitute recently a substantial portion of contemporary esthetic restorative treatments. The resin cements have been used to bond tooth substrate and restorative materials. Due to recently introduction of the self-bonding resin luting cement based on a new monomer, filler and initiation technology has become important to study the degree of conversion of these new materials. In the present work the polymerization reaction and the filler content of dual-cured dental resin cements were studied by means of infra-red spectroscopy (FT-IR) and thermogravimetry (TG). Twenty specimens were made in a metallic mold (8 mm diameter × 1 mm thick) from each of 2 cements, Panavia® F2.0 (Kuraray) and RelyX™ Unicem Applicap (3M/ESPE). Each specimen was cured with blue LED with power density of 500 mW/cm2 for 30 s. Immediately after curing, 24 and 48 h, and 7 days DC was determined. For each time interval 5 specimens were pulverized, pressed with KBr and analyzed with FT-IR. The TG measurements were performed in Netzsch TG 209 under oxygen atmosphere and heating rate of 10°C/min from 25 to 700°C. A two-way ANOVA showed DC (%) mean values statistically significance differences between two cements (p 0.05). The Relx-Y™ Unicem mean values were significantly higher than Panavia® F 2.0. The degree of conversion means values increasing with the storage time and the filler content showed similar for both resin cements.

Purpose: All-ceramic crowns are subject to fracture during function, especially in the posterior area. The use of yttrium-stabilized zirconium-oxide ceramic as a substructure for all-ceramic crowns to improve fracture resistance is unproven. The aim of this study was to compare fracture strength and fatigue resistance of new zirconium-oxide and feldspathic all-ceramic crowns made with computer-aided design/computer-aided manufacturing (CAD/CAM). Materials and Methods: An ivorine molar was prepared to receive an all-ceramic crown. Using epoxy resin, 40 replication dies were made of the prepared tooth. Twenty feldspathic all-ceramic crowns (Vita Mark II) (VMII) and 20 zirconium-oxide crown copings (In-Ceram YZ) (YZ) were made using CAD/CAM technique (CEREC-3D). The YZ copings were sintered and veneered manually with a fine-particle ceramic (VM9). All crowns were cemented to their respective dies using resin cement (Panavia F 2.0). Ten crowns in each group were subjected to compressive fatigue loading in a universal testing machine (instron). The other ten crowns from each group were loaded to fracture at a crosshead speed of 1 mm/min. Data were statistically analyzed using independent t-test and Fisher's exact test at α= 0.05. Results: There was a significant difference between the survival rates of the two materials during the fatigue test (p < 0.001). All VMII crowns survived without any crack formation, while all YZ crowns fractured (40%) or developed cracks (60%). All the YZ crown fractures occurred within the veneering layer during the fatigue test. There was no significant difference in mean fracture load between the two materials (p= 0.268). Mean fracture loads (standard deviation) in N were: 1459 (492) for YZ crowns and 1272 (109) for VMII crowns. Conclusions: The performance of VMII crowns was superior to YZ crowns in the fatigue test. The premature fractures and cracks of the YZ crowns were attributed to weakness in the YZ veneer layer or in the core/veneer bond.

Purpose The purpose of this study was to evaluate the effect of self-adhesive and self-etching resin cements on the bond strength of nonmetallic posts in different root regions. Materials and methods Sixty single-rooted human teeth were decoronated, endodontically treated, post-space prepared, and divided into six groups. Glass-fiber (GF) posts (Exacto, Angelus) and fiber-reinforced composite (FRC) posts (EverStick, StickTeck) were cemented with self-adhesive resin cement (Breeze) (SA) (Pentral Clinical) and self-etching resin cement (Panavia-F) (SE) (Kuraray). Six 1-mm-thick rods were obtained from the cervical (C), middle (M), and apical (A) regions of the roots. The specimens were then subjected to microtensile testing in a special machine (BISCO; Schaumburg, IL, USA) at a crosshead speed of 0.5 mm/min. Microtensile bond strength data were analyzed with two-way ANOVA and Tukey's tests. Results Means (and SD) of the MPa were: GF/SA/C: 14.32 (2.84), GF/SA/M: 10.69 (2.72), GF/SA/A: 6.77 (2.17), GF/SE/C: 11.56 (4.13), GF/SE/M: 6.49 (2.54), GF/SE/A: 3.60 (1.29), FRC/SA/C: 16.89 (2.66), FRC/SA/M: 13.18 (2.19), FRC/SA/A: 8.45 (1.77), FRC/SE/C: 13.69 (3.26), FRC/SE/M: 9.58 (2.23), FRC/SE/A: 5.62 (2.12). The difference among the regions was statistically significant for all groups (p < 0.05). The selfadhesive resin cement showed better results than the selfetching resin cement when compared to each post (p < 0.05). No statistically significant differences in bond strengths of the resin cements when comparable to each post (p > 0.05). Conclusion The bond strength values were significantly affected by the resin cement and the highest values were found for self-adhesive resin cement. How to cite this article da Silva MB, de Jesus Tavarez RR, de Assis FS, Tonetto MR, Porto TS, Bhandi SH, El-Mowafy O, de Toledo Porto Neto S, Bandeca MC. The Effect of Self-adhesive and Self-etching Resin Cements on the Bond Strength of Nonmetallic Posts in Different Root Thirds. J Contemp Dent Pract 2015;16(2):147-153.

O objetivo deste estudo foi determinar o efeito da polimerização gradual, mediante a utilização de aparelhos de Quartzo-Tungustênio-Halógena (QTH) e Arco de Plasma de Xenônio (PAC), no selamento marginal de restaurações classe V em resina composta com margens localizadas em dentina. Setenta e cinco incisivos bovinos receberam preparos de cavidades classe V, na raiz, com o intuito de situar as margens cavitárias em dentina. Os dentes foram divididos em cinco grupos de acordo com o método de fotoativação. As cavidades, depois de condicionadas, foram tratadas com o sistema adesivo Single Bond (3M Dental) e restauradas com a resina composta Z100 (3M Dental) pela técnica incremental. A fotoativação foi realizada para cada grupo como descrito a seguir: Grupo I: PAC pelo método de fotoativação constante: 1600mW/cm2 – 3s; Grupo II: PAC pelo método de fotoativação por passos (800mW/cm2 – 2s, subindo automaticamente para 1600mW/cm2 – 4s); Grupo III: QTH pelo método de fotoativação constante: 400 mW/cm2 – 40s; Grupo IV: QTH pelo método de fotoativação em rampa: 100 a 600 mW/cm2 – 15s, permanecendo a 600mW/cm2 por mais 25s; Grupo V: QTH pelo método de fotoativação por pulso: 200 mW/cm2 – 3s, tempo de espera de 3min.e a seguir 600mW/cm2 – 30s. Os dentes foram armazenados em água destilada a 37ºC por 30 dias e então submetidos à ciclagem térmica, por 500 ciclos à 5 ºC e 55 ºC. Os ápices dos dentes foram selados com resina composta e os dentes foram cobertos com duas camadas de esmalte para unha, antes da sua imersão em fucsina básica a 0,5%. Os dentes foram seccionados e os cortes foram escaneados para avaliação da área infiltrada por corante por um programa de computador (Image Tools). Os cortes foram também visualizados com lupa para a determinação do grau de penetração do corante na interface dente-restauração por escores. Diferenças estatisticamente significantes foram observadas entre os grupos quanto ao grau e à área de penetração de corante (p < 0,05). Os grupos I e II apresentaram valores significantemente mais altos de infiltração e penetração do corante que os grupos III, IV e V. Em conclusão, o uso da fonte de PAC, no modo constante e por passos, resultou em valores significantemente maiores de infiltração marginal quando comparados com a intensidade de luz média emitida pelos aparelhos de QTH. Os métodos de fotoativação por pulso, rampa e continuo com a fonte de QTH resultaram num grau similar de microinfiltração. The aim of this study was to determine the effect of a softstart polymerization method from Quartz-Tungsten-Halogen (QTH) and Plasma Arc (PAC) curing units on microleakage of Class V composite resin restorations with dentin cavosurface margins. Seventy-five bovine incisors received standardized class V cavities in all dentin margins. Teeth were divided into 5 equal groups according to the curing cycle. The cavities were incrementally restored with a composite resin (Single Bond/Z-100, 3M). Light curing was applied as follows: Group I: PAC light continuous-cycle curing at 1600 mW/cm2 for 3s; Group II: PAC light step-cycle curing (2s at 800 mW/cm2 then 4s at 1600 mW/cm2); Group III: QTH light continuous-cycle curing at 400 mW/cm2 for 40s; Group IV: QTH light ramp-cycle curing (from 100 to 600 mW/cm2 in 15s followed by 25s at 600 mW/cm2); Group V: QTH light pulse-delay curing (200 mW/cm2 for 3s followed by 3 min delay then 600 mW/cm2 for 30s). Teeth were stored in distilled water at 37ºC for 30 days and then subjected to thermocycling for 500 cycles at 5 and 55ºC. Root apices were sealed and teeth coated with nail varnish before they were immersed in 0.5% fuchsine red dye solution. Teeth were then sectioned and slices were scanned with a computer scanner to determine the area of dye leakage using a computer program (Image Tools). Images of tooth slices were also visually examined under magnification and dye penetration along the tooth/restoration interface was scored. Significant differences in the degree of dye penetration and leakage were detected between groups (p

Aim This study investigated the effect of different fiber inserts (glass and polyethylene), bonding agents, and resin composites on the gingival margin microleakage of class V composite restorations. Materials and methods Sixty premolars were sterilized and mounted in acrylic resin bases. Class V cavities were prepared buccally and lingually, 1 mm below the cementoenamel junction, comprising 12 groups (n = 10). In the experimental groups fiber inserts were cut and placed at the gingival seat, while the control groups had no inserts. Combinations of two composite materials, Filtek-Z250 and Filtek-LS (3M-ESPE), and four bonding agents, Clearfil SE bond (Kuraray) (C), Scotch Bond Multipurpose (3M-ESPE) (SB), Prime and Bond NT (Dentsply) (PB), and Filtek-LS (3M-ESPE) (LS) were used. Restorations were incrementally inserted and polymerized for 40s. Specimens were then stored in distilled water for 7 days and thermocycled for 500 cycles. Teeth surfaces were sealed with nail polish except for 1 mm around restoration margins and immersed in 2% red procion dye. Teeth were then sectioned buccolingually and dye penetration was assessed with five-point scale. Data were statistically-analyzed by Kruskal-Wallis, ANOVA and Tukey's tests (α = 5%). Results Mean microleakage scores varied from 0.40 (Groups C, C with polyethylene, LS, LS with polyethylene) to 1.50 (SB). Conclusion Different bonding agents led to differences in microleakage scores where C and LS showed significantly lower microleakage than PB. SB had highest mean microleakage score, however, incorporation of fibers resulted in significant reduction in microleakage. Clinical significance Class V resin composite restorations bonded with a total-etch adhesive had a significant reduction in mean microleakage scores when glass or polyethylene fibers were placed at the gingival cavo-surface margin. In contrast, for two self-etch adhesive systems, the incorporation of fibers had no significant effect on mean microleakage scores. How to cite this article Ahmed W, El-Badrawy W, Kulkarni G, Prakki A, El-Mowafy O. Gingival Microleakage of Class V Composite Restorations with Fiber Inserts. J Contemp Dent Pract 2013;14(4):622-628.

This article describes CAD/CAM technology used in dentistry and different restorative materials used in conjunction with adhesive cementation with particular attention given to the evolution of the CEREC system, as well as various ceramics developed for this system. Advantages and limitations of materials and technique are also discussed.

Dual-cure inlay resin cements polymerize both chemically and through light activation; however, clinically some aspects of the cement are not readily accessible to the light source. This study investigated the degree of cement hardening achieved through chemical curing only versus dual curing and the effect of inlay thickness on cement hardness. Disks 6 x 2.5 mm were prepared from seven commercially available cements. Eight specimens were prepared from each material; half of the specimens were cured chemically only, and the remainder were dual-cured. Knoop hardness measurements were then recorded at 1-hour, 1-day, and 1-week intervals. In addition, 24 specimens of the same dimensions were prepared from each cement. Twelve specimens were dual-cured through resin composite spacers of varying thicknesses (1 to 6 mm), and the others were cured through similar ceramic spacers, and hardness measurements were recorded. Multivariate analysis of variance revealed significant differences in hardness of chemically cured versus dual-cured specimens at the 5% level of significance for all examined cements. Significant differences were also found in the hardness of specimens dual cured through ceramic or resin composite spacers 2 to 3 mm in thickness or more versus those that were dual cured without spacer regardless of the spacer material. It is concluded that chemical curing alone was not sufficient to achieve maximum hardening of the examined cements. Cement hardness was significantly reduced when inlay thickness was 2 to 3 mm or more.

To investigate the effect of prepolymerization warming on composites' mechanical properties, three composites were evaluated: Clearfil Majesty (CM) (Kuraray), Z-100 (3M/ESPE), and Light-Core (LC) (Bisco). Specimens were prepared from each composite at room temperature as control and 2 higher temperatures (37∘Cand54∘C) to test surface hardness (SH), compressive strength (CS), and diametral tensile strength (DTS). Data were statistically analyzed using ANOVA and Fisher's LSD tests. Results revealed that prewarming CM and Z100 specimens significantly improved their SH mean values (P<0.05). Prewarming also improved mean CS values of Z100 specimens (P<0.05). Furthermore, DTS mean value of CM prepared at52∘was significantly higher than that of room temperature specimens (P<0.05). KHN, CS, and DTS mean values varied significantly among the three composites. In conclusion, Prewarming significantly enhanced surface hardness of 2 composites. Prewarming also improved bulk properties of the composites; however, this improvement was significant in only some of the tested materials.

The aim of this study was to determine the influence of different types of posts and post head designs on the fracture resistance of a composite resin core material using the diametral tensile strength (DTS ). Seventy-five disc specimens were prepared using a composite core and prefabricated glass fiber posts and were divided into four test groups and one control group (n=15). The use of fiber posts reduced the DTS of the composite core material; the DTS value of the control material was significantly higher (p=0.05) than all of the test groups.

This study evaluated the combined effects of thermocycling and compressive load-cycling on microleakage of computer-aided design/computer-assisted manufacture molar crowns. Sixteen ceramic (Vita Mark-II) and 16 composite resin (Paradigm MZ-100) crowns were milled using the CEREC 3D system. Eight crowns of each group were cemented to prepared molars using Panavia F 2.0, and 8 were cemented using RelyX Unicem Clicker. Specimens were thermocycled for 500 cycles and subjected to load-cycling for 1,000,000 cycles (60 to 600 N). Specimens were then tested for microleakage. Data were analyzed statistically using the Tukey post hoc test. All composite resin crowns survived load and thermal fatigue, while 6 ceramic crowns developed cracks. There were no statistically significant differences among groups regarding microleakage scores. Paradigm MZ-100 crowns were more crack-resistant to combined load and thermal fatigue than those composed to Vita Mark-II. However, microleakage scores of both types of crowns were similar. Int J Prosthodont 2011;24:376-378.

Resistance of machined crowns to microleakage when cemented with new self-adhesive cements has not been fully investigated. This study evaluated microleakage of machined crowns milled from porcelain and composite blocks and bonded to teeth with self-adhesive and conventional resin cement.Thirty-two freshly extracted premolars of similar shape and size were sterilized and mounted in resin blocks. Teeth received standard crown preparations with 1-mm circumferential shoulder finish line, flat occlusal surface reduced by 2 mm, and ideal angle of convergence. Prepared teeth were divided into two equal groups and assigned to either porcelain (Vita Mark II, Vident) or composite (Paradigm MZ100, 3M ESPE) blocks for crown fabrication. Optical impressions were captured for each tooth with the intraoral camera of a CEREC 3D machine. Crowns were designed and milled from both materials. Each group was then subdivided into two subgroups (n = 8) according to cement used (self-adhesive resin cement, RelyX Unicem, 3M ESPE or resin cement with self-etching adhesive, Panavia F 2.0, Kuraray). Following seating, a 5-kg weight was applied on the occlusal surface of the crown for 5 minutes. Specimens were then stored in water at 37°C for 24 hours. Specimens were thermocycled for 3000 cycles between 5°C and 55°C, then coated with nail varnish and immersed in a 2.0% basic red fuchsine dye solution for 24 hours. Teeth were then rinsed and sectioned mesiodistally and assessed under magnification for microleakage. A five-point scale was used to score degree of microleakage. Data were statistically analyzed with 2-way ANOVA and Kruskal-Wallis nonparametric test.Crown material had no significant effect on microleakage (p= 0.67); however, cement type had a significant effect (p0.0001), with Panavia F 2.0 resulting in lower microleakage scores than RelyX Unicem.Compared to the self-adhesive cement, the resin cement with separate primer/bonding agent resulted in significantly lower microleakage scores, irrespective of crown material.