Publications by authors named "Claudio Poggio"

90 Publications

Cytotoxicity of Different Composite Resins on Human Gingival Fibroblast Cell Lines.

Biomimetics (Basel) 2021 Apr 20;6(2). Epub 2021 Apr 20.

Unit of Biochemestry, Departement of Molecular Medicine, University of Pavia, 27100 Pavia, Italy.

The aim of the present study was to evaluate and compare the cytotoxic effects of eight composite resins on immortalized human gingival fibroblasts. Composite resins were eluted in cell culture medium for 48 or 72 h at 37 °C. Immortalized human gingival fibroblast-1 (HGF-1) cell lines were seeded in 96-well (1 × 10) plates and incubated for 24 h at 37 °C with the obtained extraction medium. The percentage of viable cells in each well (MTT test) was calculated relative to control cells, which were set to 100%. Data observed were not normally distributed, and nonparametric statistical methods were used for statistical analysis. The Wilcoxon test was used for intragroup comparison, and the Kruskal-Wallis test was used for intergroup multiple comparisons. Significance value was set as < 0.05. All materials tested showed cytotoxic effects on gingival fibroblasts, recordable as noncytotoxic, mildly cytotoxic or severely cytotoxic, depending on the percentage of cell viability. The Wilcoxon test for intragroup comparison showed that the percentage of viable cells decreased significantly for extracts, for all composite resins tested. The composite resins contained monomers that displayed cytotoxic properties. BisGMA, TEGDMA and UDMA had inhibitory effects and induced apoptotic proteins in pulp fibroblast. Composite resins that contained lower percentages of unbound free monomers-and that released less ions-possessed superior biocompatibility in vitro.
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http://dx.doi.org/10.3390/biomimetics6020026DOI Listing
April 2021

Exposure of Biomimetic Composite Materials to Acidic Challenges: Influence on Flexural Resistance and Elastic Modulus.

Biomimetics (Basel) 2020 Oct 28;5(4). Epub 2020 Oct 28.

Department of Clinical, Surgical, Diagnostic and Paediatric Sciences-Section of Dentistry, University of Pavia, Piazzale Golgi 2, 27100 Pavia, Italy.

Acidic conditions of the oral cavity, including soft drinks and cariogenic bacteria, represent a damage for restorative biomimetic composite materials. The aim of this study is to assess the influence of two different acidic challenges on the flexural strength and elastic modulus of five composites: x-tra fil (Group 1, XTF), GrandioSO x-tra (Group 2, GXT), Admira Fusion x-tra (Group 3, AFX), VisCalor bulk (Group 4, VCB), and Enamel Plus HRi (Group 5, EPH). Thirty samples for each group were randomly divided and assigned to three different treatments: storage in distilled water as the controls (subgroups 1a-5a), 3 weeks distilled water + 1 week Coca-Cola (subgroups 1b-5b), and 4 weeks Coca-Cola (subgroups 1c-5c). For each subgroup, the flexural strength and elastic modulus were measured using an Instron universal testing machine, and data were submitted to statistical analysis. Considering subgroups B, no material showed a significant difference in the flexural strength with the controls ( > 0.05), whereas for subgroups C, only GXT and VCB showed significantly lower values ( < 0.05). AFX reported the lowest flexural strength among the materials tested. As regards the elastic modulus, no material showed a significant variation after acidic storages when compared with the respective control ( > 0.05). AFX and EPH reported the lowest elastic modulus compared to the other materials. All composites tested showed adequate flexural properties according to the standards, except for AFX. This biomimetic material, along with EPH, might be indicated for V class (cervical) restorations considering the lowest values of elasticity reported.
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http://dx.doi.org/10.3390/biomimetics5040056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7709636PMC
October 2020

Copper-Alloy Surfaces and Cleaning Regimens against the Spread of SARS-CoV-2 in Dentistry and Orthopedics. From Fomites to Anti-Infective Nanocoatings.

Materials (Basel) 2020 Jul 22;13(15). Epub 2020 Jul 22.

Department of Clinical, Surgical, Diagnostic and Pediatric Sciences-Section of Dentistry, University of Pavia, Piazzale Golgi 2, 27100 Pavia, Italy.

The latest diffusion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the coronavirus disease (COVID-19), has involved the whole world population. Even if huge efforts to control the pandemic have been done, the viral spread is still continuing. COVID-19 is reported as a zoonosis jumped from bats and pangolins to humans. After infection in humans, SARS-CoV-2 is found in the nasopharyngeal and salivary secretions. The virus has also been detected in the blood plasma of infected patients. The viral spread occurs through droplets exhaled from the nose and mouth of the infected people when they breath or talk, or through droplets propelled as a dense cloud by chough or sneeze. The virus can also be delivered as an aerosol from blood plasma, through surgical procedures. Following these ways, the virus can disperse in the air, then reaching and settling on the exposed surfaces. How long the virus will survive on a surface depends on the material the surface is made from. Infection via high-touch surfaces should be prevented. Copper alloy coatings, combined with efficient hygienic/disinfectant procedures and careful surgical practice, could be helpful to health protection in dental practice and can also be adopted in orthopedic traumatology.
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http://dx.doi.org/10.3390/ma13153244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7435369PMC
July 2020

Ozonized Gel Against Four Species: A Pilot Study and Clinical Perspectives.

Materials (Basel) 2020 Apr 8;13(7). Epub 2020 Apr 8.

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, Section of Dentistry, University of Pavia, 27100 Pavia, Italy.

Ozone therapy can display a wide range of clinical beneficial effects, including antimicrobial, immune-stimulant, analgesic, anti-hypoxic actions. However, there is still a paucity of data regarding the ozone fungicide activity. Oral is the most common fungal infection in the mouth among denture wearers and people with weakened immune systems. In the case of generalized candidiasis or immunocompromised patients, systemic therapy is needed, while localized infections are treated with topic medications. However, many strains are resistant to antifungal drugs. The aim of this preliminary analysis is to evaluate the antimycotic efficacy of a new ozonided oil (GeliO), as a possible terapeutic alternative in local treatments of these infections, compared to chlorhexidine digluconate (Plak gel®). Chlorhexidine is a chemical synthesis disinfectant with a broad-spectrum antiseptic action, active against bacteria and fungi. Antimycotic activity was tested against the following four species: , , , , through an agar diffusion method. No significant differences were found between the growth inhibition zone diameters of the ozonized gel and chlorhexidine. The results indicated that the ozonized gel may help to combat infections. Moreover, useful applications could be used to counteract colonization of endosseous implants.
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http://dx.doi.org/10.3390/ma13071731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178640PMC
April 2020

New Resin-Based Bulk-Fill Composites: Evaluation of Micro-Hardness and Depth of Cure as Infection Risk Indexes.

Materials (Basel) 2020 Mar 13;13(6). Epub 2020 Mar 13.

Department of Clinical, Surgical, Diagnostic and Paediatric Sciences - Section of Dentistry, University of Pavia, Piazzale Golgi 2, 27100 Pavia, Italy.

The current study evaluated the Vickers hardness number (VHN) and hardness ratio of four bulk-fill composites (VisCalor bulk; Admira Fusion x-tra; x-tra fil; and GrandioSO x-tra-Voco, Cuxhaven, Germany) to assess the risk of bacterial colonization in comparison with standard composite materials. Thirty samples were prepared for each group. The VHN of both the external (top) and internal surface (bottom) was determined with a micro-hardness tester (200 g load for 15 s), and the hardness ratio was also calculated for each sample. Subsequently, storage in an acidic soft drink (Coca-Cola, Coca-Cola Company, Milano, Italy) was performed; for each group, 10 samples were stored for 1 day, while another 10 were stored for 7 days and the remaining 10 were kept in water as controls. A significant reduction in VHN was shown for all the groups when comparing the external versus internal side (P < 0.05), although the hardness ratio was greater than 0.80, resulting in an adequate polymerization. Regarding the acid storage, all the groups showed a significant decrease of VHN when compared with the controls, both after 1 day (P < 0.05) and after 7 days (P < 0.001). All the products showed adequate depth of cure without further risk of bacterial colonization. However, acid exposure negatively affected micro-hardness values, which might promote subsequent colonization.
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http://dx.doi.org/10.3390/ma13061308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7143874PMC
March 2020

In Vitro Re-Hardening of Bleached Enamel Using Mineralizing Pastes: Toward Preventing Bacterial Colonization.

Materials (Basel) 2020 Feb 11;13(4). Epub 2020 Feb 11.

Department of ClinicalSurgical, Diagnostic and Paediatric SciencesSection of Dentistry, University of Pavia, 27100 Pavia, Italy.

The search for materials able to remineralize human hard tissues is a modern medical challenge. In this study, the protective effect on the enamel microhardness by a paste based on hydroxyapatite and sodium fluoride (Remin Pro) was evaluated after two different enamel bleaching procedures. Forty sound human incisors were randomly assigned to different treatments: bleaching with an in-office agent (Perfect Bleach Office+); bleaching with an at-home agent (Perfect Bleach); bleaching with the in-office agent followed by the prophylaxis paste; bleaching with the athome agent followed by the prophylaxis paste; no treatment (control). Bleaching was performed at 0, 8, 24 and 32 h, followed by a 3min remineralizing treatment in the subgroups designed to receive it. Specimens underwent a microhardness tester and a mean Vickers Hardness number was considered for each specimen. ANOVA exhibited significant differences among groups. Posthoc Tukey testing showed significant microhardness decrease after the application of both the two bleaching agents. The treatment with prophylaxis paste significantly increased the microhardness values of bleached enamel.
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http://dx.doi.org/10.3390/ma13040818DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7079603PMC
February 2020

Influence of Different Surface Pretreatments on Shear Bond Strength of an Adhesive Resin Cement to Various Zirconia Ceramics.

Materials (Basel) 2020 Feb 1;13(3). Epub 2020 Feb 1.

Department of Clinical, University of Pavia, Surgical, Diagnostic and Paediatric Sciences - Section of Dentistry, Piazzale Golgi 2, 27100 Pavia, Italy.

The aim of this in vitro study was to assess the influence of surface pretreatment on shear bond strength (SBS) of an adhesive resin cement (G-CEM Link Force TM, GC Corporation, Tokyo, Japan) to three different yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics: (1) Copran Zirconia Monolith HT, COP; (2) Katana ML Zirconia, KAT; and (3) Metoxit Z-CAD HTL Zirconia, MET. In total, 45 cylinders (5 mm in diameter, 1 mm height) for each type of zirconia ceramic were prepared used a computer-aided design and computer-aided manufacturing (CAD/CAM) machine (software CEREC 4.2). Each type of zirconia was subdivided into three groups and each group received a different surface pretreatment; 15 samples were not conditioned as control (groups COP 1, KAT 1, MET 1), 15 samples were air-borne particle abraded with aluminum dioxide particles of 50-μm size at 0.3 MPa for 20 s (groups COP 2, KAT 2, MET 2), and 15 samples were hot-etched with a solution of hydrochloric acid and ferric chloride (groups COP 3, KAT 3, MET 3). After specimen fabrication, the adhesive cement-ceramic interface was analyzed using an SBS test. Subsequently, the adhesive remnant index (ARI) was measured. Data were submitted to statistical analysis. Air-borne particle abraded specimens showed the highest SBS values for COP and KAT groups. For MET, no significant difference was reported between air-borne particle abraded specimens and untreated controls. The lowest values were detected for acid-etched groups. A higher frequency of ARI = "1" and ARI = "2" was reported in control and air-borne particle abraded groups, whereas ARI = "3" was detected in hot-etched groups. No correlation was found between ARI score and shear bond strength. Air-borne particle abrasion is considered the best treatment for Zirconia Copran and Zirconia Katana ML, if it is followed by using dual-curing resin cement.
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http://dx.doi.org/10.3390/ma13030652DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040603PMC
February 2020

Evaluation of the actual chlorine concentration and the required time for pulp dissolution using different sodium hypochlorite irrigating solutions.

J Conserv Dent 2019 Mar-Apr;22(2):108-113

Department of Endodontics, Faculty of Dentistry, University of Alexandria, Alexandria, Egypt.

Introduction: The goal of root canal treatment is to shape and clean the endodontic space, reducing the bacterial load and removing the pulp tissue. Obviously, the action of the endodontic instruments is limited to the main canals, regardless of the complexity of the endodontic space. Consequently, finding the best possible cleaning technique, which can be obtained chemically using irrigation solutions, is a fundamental aid in endodontic therapy. One of the most commonly used root canal irrigants is sodium hypochlorite (NaOCl), available in various commercial formulations. The effectiveness of NaOCl is undeniable. However, the action of dissolution of the pulp tissue is merely dependent on the concentration and the characteristics of the irrigant itself.

Aim: The aim of this study is to evaluate the effective concentration of different commercial formulas of NaOCl, by evaluating the percentage of total chlorine in each product. The dissolution capacity of the pulp tissue of each of the tested products was then analyzed by measuring the required time.

Materials And Methods: Three commercial types of NaOCl were selected for this study: 5% NaOCl (ACE, Procter and Gamble), 5% NaOCl (N5, Simit Dental), and 6% NaOCl (CanalPro, Coltene). For each product, 10 packages were used, from which samples of the product were taken and 30 ml × 5 ml tubes were filled. All samples were divided into three groups and were analyzed using the DIN EN ISO 7393-2 method and the percentage of total chlorine (expressed as a percentage) was calculated. Forty samples of vital pulp were obtained from teeth freshly extracted for periodontal reasons and stored in physiological solution. In order to unify the size and weight of the samples (0.0001 mg), a microtome and a precision balance (Pro Explorer Ohaus) were used. Each sample, carefully examined by stereomicroscope (×40), was placed in artificial plastic containers and submerged in 0.1 ml of irrigating solution at room temperature (26°C). A fourth control group used saline solution as irrigant. Simultaneously with the insertion of the irrigating solution, a digital stopwatch was activated and the time necessary for the complete dissolution of the pulp sample was measured. The data obtained was subjected to statistical analysis.

Results: The average percentages of chlorine detected for each group were: 4.26% (ACE), 5.16% (N5), and 5.97% (CanalPro). The Kruskal-Wallis test showed statistically significant differences between the different commercial formulations of hypochlorite ( < 0.05). CanalPro showed the lowest values, whereas ACE showed the highest values of dissolution time of the pulp.

Discussion: The analysis of the total chlorine percentage found that the actual concentration of the NaOCl in the samples is close to the values declared by the manufacturers both in the case of N5 and CanalPro. On the contrary, the concentration detected in the samples of common bench bleach (ACE) is significantly lower, which has average values <5%. This explains the longer time taken for the complete dissolution of the pulp tissue. The average dissolution time of the pulp samples was in fact inversely proportional to the concentration detected in the tested irrigants and hence that a lower time corresponds to a higher concentration.
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http://dx.doi.org/10.4103/JCD.JCD_165_19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6519176PMC
May 2019

Vickers Micro-Hardness of New Restorative CAD/CAM Dental Materials: Evaluation and Comparison after Exposure to Acidic Drink.

Materials (Basel) 2019 Apr 16;12(8). Epub 2019 Apr 16.

Unit of Orthodontics and Paediatric Dentistry, Section of Dentistry, Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, 27100 Pavia, Italy.

CAD/CAM (computer-aided design/computer-aided manufacturing) for indirect restorative materials has been recently introduced in dentistry. The purpose of this study was to evaluate the change of the surface micro-hardness of different restorative CAD/CAM materials after exposure to a carbonated acidic drink (Coca-Cola, Coca-Cola Company, Milan, Italy). One hundred and eighty specimens of identical size (2 mm thickness) were obtained by sectioning each tested CAD/CAM block of four materials: a hybrid ceramic (CERASMART™, GC Corporation, Tokyo, Japan), a resin nano ceramic (Lava™ Ultimate, 3M, Monrovia, CA, USA), a nanohybrid composite (Grandio blocs, VOCO GmbH, Cuxhaven, Germany), and a zirconia-reinforced lithium silicate glass ceramic (VITA SUPRINITY PC; VITA Zahnfabrik, Bad Sackingen, Germany). Forty-five specimens of each material were tested. Micro-hardness was measured at baseline, after 7 days and after 28 days. The data were analyzed. The micro-hardness of each material varied significantly after immersion in Coca-Cola. The nanohybrid composite had a high initial micro-hardness and the greatest percentage loss after acid exposure. The hybrid ceramic and the resin nano ceramic had similar percentage losses of micro-hardness values even if the second material had higher initial values. The zirconia-reinforced lithium silicate glass ceramic had the highest baseline values and the lowest percentage loss of micro-hardness. The different CAD/CAM materials presented different micro-hardness values before and after acid exposure.
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http://dx.doi.org/10.3390/ma12081246DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6515223PMC
April 2019

Flexural Properties and Elastic Modulus of Different Esthetic Restorative Materials: Evaluation after Exposure to Acidic Drink.

Biomed Res Int 2019 4;2019:5109481. Epub 2019 Feb 4.

Unit of Restorative Dentistry, Section of Dentistry, Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy.

Background: Acidic beverages, such as soft drinks, can produce erosion of resin composites. The purpose of the present study was to investigate mechanical properties of different esthetic restorative materials after exposure to acidic drink.

Methods: Nine different composites were tested: nanofilled (Filtek Supreme XTE, 3M ESPE), microfilled hybrid (G-ænial, GC Corporation), nanohybrid Ormocer (Admira Fusion, Voco), microfilled (Gradia Direct, GC Corporation), microfilled hybrid (Essentia, GC Corporation), nanoceramic (Ceram.X Universal, Dentsply De Trey), supranano spherical hybrid (Estelite Asteria, Tokuyama Dental Corporation), flowable microfilled hybrid (Gradia Direct Flo, GC Corporation), and bulk fill flowable (SureFil SDR flow, Dentsply De Trey). Thirty specimens of each esthetic restorative material were divided into 3 subgroups (n=10): specimens of subgroup 1 were used as control, specimens of subgroup 2 were immersed in 50 ml of Coca Cola for 1 week, and specimens of subgroup 3 were immersed in 50 ml of Coca Cola for 1 month. Flexural strength and elastic modulus were measured for each material with an Instron Universal Testing Machine. Data were submitted to statistical analysis.

Results: After distilled water immersion, nanofilled composite showed the highest value of both flexural strength and elastic modulus, but its flexural values decreased after acidic drink immersion. No significant differences were reported between distilled water and acidic drink immersion for all other materials tested both for flexural and for elastic modulus values.

Conclusions: Even if nanofilled composite showed highest results, acidic drink immersion significantly reduced flexural values.
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http://dx.doi.org/10.1155/2019/5109481DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6378791PMC
June 2019

Effect of different protective agents on enamel erosion: An in vitro investigation.

J Clin Exp Dent 2019 Feb 1;11(2):e113-e118. Epub 2019 Feb 1.

Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy.

Background: The purpose of this study was to compare the effect of different protective agents on enamel erosion by measuring mean percentage weight loss.

Material And Methods: Extracted teeth were sectioned into uniform slabs and enamel specimens were randomly distributed to different groups. Initial weight of all enamel specimens was registered. The protective agents used in this study were Tooth Mousse, MI Paste Plus, Remin Pro and Remin Pro Forte. A control group was treated just with tap water. All the specimens were immersed in Coca-Cola for a total of 8 min at room temperature, dried and weighed. Enamel dissolution caused by acidic soft drink was analyzed: specimens were weighed after each immersion period and mean percent weight loss was calculated. Weight loss data were subjected to Analysis of Variance (One-way ANOVA) followed by Bonferroni's post hoc tests.

Results: All the groups showed a statistically significant loss of weight (<0.01) during the testing periods, increased after 8 days (~55%) and 12 days (~70%) of exposure. Specimens treated with protective agents showed significantly lower % of weight loss especially with Remin Pro or Remin Pro Forte.

Conclusions: Soft drinks can cause enamel erosion, but protective agents tested may enhance enamel resistance against erosion. Enamel, erosion, protective agents, soft drinks, toothpastes.
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http://dx.doi.org/10.4317/jced.55278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6383899PMC
February 2019

Evaluation of the antibacterial activity of a new ozonized olive oil against oral and periodontal pathogens.

J Clin Exp Dent 2018 Nov 1;10(11):e1103-e1108. Epub 2018 Nov 1.

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences - Section of Dentistry, University of Pavia, Pavia, Italy.

Background: In the present study, the antimicrobial properties of a new ozonized olive oil (O-zone gel) against oral and periodontal pathogens will be evaluated and compared with that of common CHX-based agents.

Material And Methods: O-zone gel was compared with two agents based on chlorhexidine digluconate (CHX): Corsodyl Dental Gel and Plak Gel. A. actinomycetemcomitans, P. intermedia and S. mutans, were selected and the antibacterial capability of the compounds was tested by using direct contact agar diffusion test (DCT) and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) evaluations. Differences between specific means were analyzed by a one-way analysis of variance (ANOVA). Group means were compared using a one-way ANOVA and Tukey's test (<0.05).

Results: O-zone gel reported inhibition zones which correspond to 33% and 43% of that achieved by the CHX agents. No inhibition of bacterial growth (MIC) on the Gram-positive strain by using O-zone gel was found and no antimicrobial effect (MBC) was observed by using O-zone gel on both Gram-negative and -positive strains.

Conclusions: The new ozonated oil was a relatively moderate antiseptic. Gram-negative bacteria proved to be more sensitive to ozonized olive oil than Gram-positive ones. The ozonized olive oil demonstrated a lower antibacterial activity if compared to the CHX-based agents tested. Agar diffusion test, antibacterial activity, direct contact test, ozone, ozonized olive oil.
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http://dx.doi.org/10.4317/jced.54929DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6311406PMC
November 2018

Effect of different finishing/polishing procedures on surface roughness of Ormocer-based and different resin composites.

Dent Res J (Isfahan) 2018 Nov-Dec;15(6):404-410

Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, Section of Dentistry, University of Pavia, Pavia, Italy.

Background: The aim of this study was to evaluate and compare the surface roughness of six esthetic restorative materials (Gradia Direct Anterior, GC Corporation, Tokyo, Japan; Filtek Supreme XTE, 3M ESPE, St. Paul, MN, USA; Ceram.X Universal, Dentsply DeTrey, Konstanz, Germany; Essentia enamel, GC Corporation, Tokyo, Japan; Admira Fusion, Voco, Cuxhaven, Germany; and Estelite, Tokuyama Dental corporation, Taitou-ku, Tokyo, Japan) achieved using three different finishing and polishing techniques.

Materials And Methods: In this study Forty specimens of each material (6 mm in diameter, 2 mm high) were created and divided into four groups, one per each finishing and polishing procedure and a control group, only cured and not polished. All specimen preparation and finishing and polishing procedures were performed by the same investigator, to reduce variability, following strictly the manufacturer's instructions. Specimens were analyzed using a profilometer to measure the mean surface roughness (Ra, μm), and microscopy images were taken during the measurements through the microscope of the profilometer. Two-way ANOVA test was applied to determine significant differences with respect to material, finishing/polishing technique, and interaction between both variables. comparison was done using Tukey's honestly significant difference test. Significance for statistical tests was predetermined at < 0.05.

Results: Finishing and polishing procedure using tungsten carbide burs provided the best values in terms of surface roughness. All materials of this study treated with this method have provided superimposable values, and no material can be considered more performing than the others. Similar values were also found in the control group.

Conclusion: This study demonstrated that the finishing technique with carbide burs produced an excellent surface smoothness, even if the best surface smoothness is achieved curing the restorative material under a polyester matrix.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243812PMC
December 2018

Cytotoxicity evaluation of a new ozonized olive oil.

Eur J Dent 2018 Oct-Dec;12(4):585-589

Departement of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy.

Objective: The cytocompatibility of a new ozonized olive oil toward immortalized human gingival fibroblasts (HGFs) was evaluated and compared with two common antimicrobial agents based on chlorhexidine digluconate (CHX).

Materials And Methods: The cytocompatibility of the samples was tested on immortalized HGF-1 cells by 3-(4, 5-dimethyl thiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay. The cells were incubated for 2 or 24 h with increasing dilution of ozonized olive oil or CHX agents. The percentage of viable cells was calculated relative to control cells set to 100%.

Results: The ozonized olive oil is cytocompatible, and the viability values of the cells treated for 2 or 24 h with increasing concentrations of ozonized olive oil were significantly higher ( < 0.01) compared with the values obtained using CHX.

Conclusions: The present data demonstrate that due to its cytocompatibility, the new ozonized olive oil could be considered an alternative antibacterial agent.
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http://dx.doi.org/10.4103/ejd.ejd_422_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6178687PMC
October 2018

Intracanal heating of sodium hypochlorite: Scanning electron microscope evaluation of root canal walls.

J Conserv Dent 2018 Sep-Oct;21(5):569-573

Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples Federico II, Naples, Italy.

Introduction: The aim of this study is to evaluate the surface of root canals dentine using scanning electron microscope (SEM) after instrumentation with rotary Nickel-Titanium systems and two different protocols of activation of sodium hypochlorite (NaOCl) (extracanal heating at 50°C and intracanal heating at 180°C), to assess the presence/absence of smear layer and also the presence/absence of open dentinal tubules along the walls at the coronal, middle, and apical third of each sample.

Materials And Methods: Thirty-six single-rooted teeth were selected, divided into three groups and shaped with ProTaper Universal instruments following irrigation protocols with 5.25% NaOCl. At the end of the preparation, three different protocols of activation were used: nonheated NaOCl in Group A, extra-canal heated NaOCl at 50°C for Group B and intracanal heated NaOCl at 180°C for Group C. Specimens were cut longitudinally and analyzed by SEM at standard magnification of ×1000. The presence/absence of the smear layer as well as the presence/absence of open tubules at the coronal, middle, and apical third of each canal were estimated using a five-step scale for scores. Numeric data were analyzed using Kruskal-Wallis and Mann-Whitney U statistical tests and significance was predetermined at < 0.05.

Results: Kruskal-Wallis analysis of variance (ANOVA) for debris score showed significant differences among the Ni-Ti systems ( < 0.05). Mann-Whitney test confirmed that Group A presented significantly higher score values than other Ni-Ti systems. The same results were assessed considering the smear layer scores. ANOVA confirmed that the apical third of the canal maintained a higher quantity of debris and smear layer after preparation of all the samples.

Discussion And Conclusions: Intra-canal heating of NaOCl at 180°C proved to be more effective in obtaining clean canal walls. On the other hand, extra-canal heating at 50°C of NaOCl left a higher quantity of debris and the smear layer was widely represented.
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http://dx.doi.org/10.4103/JCD.JCD_245_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161513PMC
October 2018

Esthetic restorative materials and glass ionomer cements: Influence of acidic drink exposure on bacterial adhesion.

Eur J Dent 2018 Apr-Jun;12(2):204-209

Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy.

Objective: The purpose of this research was to evaluate and compare bacterial adhesion on five esthetic restorative materials, three glass ionomer cements (GIC), and two GIC with coat. All the materials were considered after acidic drink exposure.

Materials And Methods: Thirty cylindrical sample of each of the 10 materials were prepared and then divided into three groups: group 1 (baseline), Group 2 (1 day in acidic soft drink), and Group 3 (7 days in acidic soft drink). Bacterial suspension of was cultured and deposited onto each material, and the adhesion was evaluated through the colony-forming units determination. One-way ANOVA and Bonferroni's tests were applied to estimate significant differences between the esthetic materials.

Results: The highest amount of was recorded in Group 3 and the lowest in Group 1 (baseline). In general, the GIC showed bacterial adhesion values higher than the ones related to composites both in Group 2 than in Group 3. Acidic soft drinks lead a time-dependent degradation of restorative materials causing an increase of the surface rugosity. In fact, a general increase in cells adhesion to treated samples was observed.

Conclusions: The use of acidic soft drink resulted in a degradation of the surface layer of the restorative material with consequent increase of bacterial adhesion. The GIC can be considered a more friendly environment for bacterial adhesion. This is true in particular if acid substances have already deteriorated the surface.
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http://dx.doi.org/10.4103/ejd.ejd_219_17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6004817PMC
July 2018

Bacterial adhesion on fissure sealants: Effects of exposure to acidic drink.

J Clin Exp Dent 2018 Jun 1;10(6):e574-e578. Epub 2018 Jun 1.

Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy.

Background: Adherence of bacteria to teeth surface is considered an important step in the development of caries and the use of fissure sealants is crucial for the prevention of caries in occlusal surfaces of molars and premolars. The aim of this study was to investigate and compare the adherence of to different fissure sealants, after acidic drink exposure.

Material And Methods: The tested materials were Fissurit, Fissurit FX, Grandio Seal, Fuji Triage, Constic. Bacterial suspension was deposited onto each material and the adhesion was evaluated trough the colony forming units (CFUs) determination with or without acidic drink exposure.

Results: The tested materials showed different behaviors with significant differences. Bacterial adherence values of the untreated materials were very dissimilar: Fuji Triage and Constic materials showed the better results (<0.05).

Conclusions: Surface alteration after acidic drink exposure, changed the bacterial adhesion (except for Grandio Seal): Fissurit, Fissurit FX and Fuji Triage decreased their susceptibility to be colonized by (<0.05); on the contrary, Constic increased up to ~4 times the bacterial adhesiveness respected to the untreated control (<0.05). Acidic drinks, bacterial adhesion, fissure sealants, Streptococcus mutans.
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http://dx.doi.org/10.4317/jced.54818DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6005089PMC
June 2018

Microhardness of different esthetic restorative materials: Evaluation and comparison after exposure to acidic drink.

Dent Res J (Isfahan) 2018 May-Jun;15(3):166-172

Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, Section of Dentistry, University of Pavia, Pavia, Italy.

Background: Acidic beverages, such as soft drinks (orange juice and cola), can produce erosion of resin composites. The aim of this study was to evaluate the effect of immersion in acidic drink on the Vickers microhardness (VK) of different esthetic restorative materials (one nanohybrid Ormocer-based composite, one nanoceramic composite, one nanofilled composite, and one microfilled hybrid composite).

Materials And Methods: In this study, thirty specimens of each esthetic restorative material were divided into three subgroups ( = 10): specimens of group 1 were used as control, specimens of group 2 were immersed in 50 ml of acidic drink for 1 day, specimens of group 3 were immersed in 50 ml of acidic drink for 7 days. Data were analyzed by Shapiro-Wilk test to assess the normality of the distributions followed by nonparametric Kruskal-Wallis analysis of variance and Mann-Whitney U-test comparison test among groups. A significant level of α = 0.05 was set for comparison between the groups.

Results: Mann-Whitney U-test showed that each material showed lower microhardness values after immersion in acidic solution ( < 0.05). Paired -test confirmed that microhardness for each composite did not change after immersion in distilled water (Control group) ( > 0.05). Significant changes were registered for all restorative materials after immersion in acidic solution for 1 day and 7 days ( < 0.05).

Conclusion: The Filtek Supreme XTE, a nanofilled composite, and Admira Fusion, a nanohybrid ormocer-based composite, showed the best behavior. The Ceram X Universal (nanoceramic composite) although reached lower hardness values than the previous materials, but resisted well to the 1 week immersion in soft-drink. Finally, the Gradia Direct achieved the most disappointing results: Low microhardness values are justified by the nature of its filling (microfilled hybrid composite).
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5958532PMC
June 2018

Shear bond strength of one-step self-etch adhesives to dentin: Evaluation of NaOCl pretreatment.

J Clin Exp Dent 2018 Feb 1;10(2):e127-e133. Epub 2018 Feb 1.

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences - Section of Dentistry, Policlinico "San Matteo", Piazzale Golgi, Pavia, Italy.

Background: The aim of this study was to evaluate the influence of dentin pretreatment with NaOCl on shear bond strength of four one-step self-etch adhesives with different pH values.

Material And Methods: Bovine permanent incisors were used. Four one-step self-etch adhesives were tested: Adper™ Easy Bond, Futurabond NR, G-aenial Bond, Clearfil S3 Bond. One two-step self-etch adhesive (Clearfil SE Bond) was used as control. Group 1- no pretreatment; group 2- pretratment with 5,25 % NaOCl; group 3- pretreatment with 37 % H3PO4 etching and 5,25 % NaOCl. A hybrid composite resin was inserted into the dentin surface. The specimens were tested in a universal testing machine. The examiners evaluated the fractured surfaces in optical microscope to determine failure modes, quantified with adhesive remnant index (ARI).

Results: Dentin pretreatment variably influenced bond strength values of the different adhesive systems. When no dentin pretreatment was applied, no significant differences were found ( >.05) among four adhesives tested. No significant differences were recorded when comparing NaOCl pretreatment with H3PO4 + NaOCl pretreatment for all adhesive tested ( >.05) except Clearfil S3 Bond that showed higher shear bond strength values when H3PO4 was applied. Frequencies of ARI scores were calculated.

Conclusions: The influence of dentin pretreatment with NaOCl depends on the composition of each adhesive system used. There was no difference in bond strength values among self-etch adhesives with different pH values. Dentin, pretreatment, self-etch adhesives.
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http://dx.doi.org/10.4317/jced.54552DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5899790PMC
February 2018

Biological and physico-chemical properties of new root canal sealers.

J Clin Exp Dent 2018 Feb 1;10(2):e120-e126. Epub 2018 Feb 1.

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences - Section of Dentistry, Policlinico "San Matteo" Piazzale Golgi, Pavia, Italy.

Background: The purpose of the present study was to compare the biological and the physico-chemical properties of bioceramic-based root canal sealers, calcium hydroxide-based, MTA-based and epoxy resin-based root canal sealers.

Material And Methods: Two bioceramic-based sealers, one calcium hydroxide-based sealer, one MTA-based sealer and two epoxy resin-based sealers were tested.

Results: EasySeal and MTA Fillapex showed severe citotoxic activity, AH Plus and SealapexTM moderate cytotoxicity, BioRoot™ RCS and TotalFill BC Sealer were both cytocompatible. Except for TotalFill BC Sealer, all root canal sealers caused inhibition zones when tested with E. faecalis. The highest inhibition zone was observed for EasySeal, followed by AH Plus. BioRoot™ RCS, SealapexTM and MTA Fillapex showed the lowest inhibition zone. All the tested materials showed different degree of antibacterial activity by using direct contact test (DCT). The highest values were observed for BioRoot™ RCS, TotalFill BC Sealer and EasySeal, followed by MTA Fillapex and SealapexTM. Except for BioRoot RCS and TotalFill BC Sealer, all the root canal sealers fulfilled the requirements of the ISO 6876 standard, demonstrating a weight loss less than 3%. Bioroot RCS, TotalFill BC Sealer and SealapexTM exhibited high alkaline pH with an increase both for BioRoot™ RCS and TotalFill BC Sealer after 24 hours.

Conclusions: The new bioceramic-based sealers showed acceptable physico-chemical properties, but BioRoot™ RCS and TotalFill BC Sealer seems to be too soluble, not respecting ISO 6876 requirements. Antibacterial activity, cytoxicity, pH, root canal sealers, solubility.
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http://dx.doi.org/10.4317/jced.54548DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5899788PMC
February 2018

Effect of different surface finishing/polishing procedures on color stability of esthetic restorative materials: A spectrophotometric evaluation.

Eur J Dent 2018 Jan-Mar;12(1):49-56

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, Section of Dentistry, University of Pavia, Pavia, Italy.

Objective: To evaluate the color stability of different esthetic restorative materials after surface finishing/polishing with different procedures.

Materials And Methods: All materials were polymerized into silicone rubber rings to obtain specimens identical in size. Samples were randomly assigned into four groups (10 specimens of each composite for each group), and they were finished with different procedures: Control group (Group 1), three or two polishers interspersed with diamond grit (Groups 3 and 2, respectively), and one tungsten carbide bur + one polisher interspersed with diamond grit (Group 4). After staining process in coffee, a colorimetric evaluation according to the CIE L*a*b* system was performed by a blind trained operator at 7, 14, 21, and 28 days. Shapiro-Wilk test and Kruskal-Wallis analysis of variance were applied to assess significant differences among restorative materials. Means of the different polishing/finishing groups were compared with Scheffe's multiple comparison test at the 0.05 level of significance.

Results: In control group, significant lower discolorations were recorded for Essentia, Admira Fusion, and Estelite. After finishing, Filtek Supreme XTE and Ceram.X Universal showed a significantly lower degree of staining. The finishing technique used for Group 4 produced higher color changes.

Conclusions: Tungsten carbide burs produced the higher color variations; after finishing, the nanofilled composites showed lower discoloration than nanohybrid ones, and the time of exposure to the staining agent and the polishing/finishing technique influenced the color change.
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http://dx.doi.org/10.4103/ejd.ejd_185_17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5883476PMC
April 2018

Color stability of CAD/CAM Zirconia ceramics following exposure to acidic and staining drinks.

J Clin Exp Dent 2017 Nov 1;9(11):e1297-e1303. Epub 2017 Nov 1.

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences - Section of Dentistry, University of Pavia, Pavia, Italy.

Background: The aim of this study was to evaluate the color stability of CAD/CAM Zirconia ceramics following exposure to acidic drink (Coca Cola) and after exposure to staining solution (coffee).

Material And Methods: All the samples were immersed in different staining solutions over a 28-day test period. A colorimetric evaluation according to the CIE L*a*b* system was performed by a blind trained operator at 7, 14, 21, 28 days of the staining process. Shapiro Wilk test and Kruskal-Wallis ANOVA were applied to assess significant differences among restorative materials. Paired t-test was applied to test which CIE L*a*b* parameters significantly changed after immersion in staining solutions.

Results: One week immersion in acidic drink did not cause a perceivable discoloration for all restorative materials (ΔE < 3.3). Subsequent immersion in coffee affected color stability of all Zirconia samples, even if Kruskal-Wallis ANOVA found significant differences among the various restorative materials.

Conclusions: The ∆Es of CAD/CAM Zirconia ceramics after immersion in coffee varied among the products, but color integrity is not affected by contact with acidic drinks. CAD/CAM restorative materials, CIE Lab, Zirconia ceramics.
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http://dx.doi.org/10.4317/jced.54404DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741842PMC
November 2017

Solubility and pH of bioceramic root canal sealers: A comparative study.

J Clin Exp Dent 2017 Oct 1;9(10):e1189-e1194. Epub 2017 Oct 1.

Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Italy.

Background: This study compared the solubility and the pH of different root canal sealers .

Material And Methods: BioRoot™RCS, TotalFill BC Sealer, MTA Fillapex, SealapexTM, AH Plus, EasySeal, Pulp Canal Sealer™ and N2 were tested. Similar specimens were prepared using ring molds with an internal diameter of 20 ± 0,1 mm and a height of 1,5 ± 0,1 mm and digitally weighted to register the mass of each specimen before and after immersion in distilled water. Solubility was determined after 24 hours and statistically analysed using a one-way ANOVA test and post-hoc Tukey test. The pH value was measured by a digital pH meter after 3 and 24 hours from manipulation.

Results: BioRoot™RCS and TotalFill BC Sealer showed significantly higher solubility (<0.05). All the remnant root canal sealers fulfilled the requirements of solubility of the International Standard Organization 6876 demonstrating a weight loss of less than 3%. BioRoot™RCS and Totalfill BC Sealer exhibited high alkaline pH over time (<0.05); the alkalinity of the other tested cements was significantly lower.

Conclusions: The prolonged alkalinity of bioceramic sealer matched the increase in solubility. This may encourage their biological and antimicrobial effects, but the ongoing solubility may impact their ability to prevent apical leakage. pH, root canal sealers, solubility.
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http://dx.doi.org/10.4317/jced.54040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5694146PMC
October 2017

Comparison of apical extrusion of intracanal bacteria by various glide-path establishing systems: an study.

Restor Dent Endod 2017 Nov 31;42(4):316-323. Epub 2017 Oct 31.

Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Pusan National University, Yangsan, Korea.

Objectives: This study compared the amount of apically extruded bacteria during the glide-path preparation by using multi-file and single-file glide-path establishing nickel-titanium (NiTi) rotary systems.

Materials And Methods: Sixty mandibular first molar teeth were used to prepare the test apparatus. They were decoronated, blocked into glass vials, sterilized in ethylene oxide gas, infected with a pure culture of randomly assigned to 5 experimental groups, and then prepared using manual stainless-steel files (group KF) and glide-path establishing NiTi rotary files (group PF with PathFiles, group GF with G-Files, group PG with ProGlider, and group OG with One G). At the end of canal preparation, 0.01 mL NaCl solution was taken from the experimental vials. The suspension was plated on brain heart infusion agar and colonies of bacteria were counted, and the results were given as number of colony-forming units (CFU).

Results: The manual instrumentation technique tested in group KF extruded the highest number of bacteria compared to the other 4 groups ( < 0.05). The 4 groups using rotary glide-path establishing instruments extruded similar amounts of bacteria.

Conclusions: All glide-path establishment instrument systems tested caused a measurable apical extrusion of bacteria. The manual glide-path preparation showed the highest number of bacteria extruded compared to the other NiTi glide-path establishing instruments.
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http://dx.doi.org/10.5395/rde.2017.42.4.316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5682148PMC
November 2017

Remineralizing effect of a zinc-hydroxyapatite toothpaste on enamel erosion caused by soft drinks: Ultrastructural analysis.

J Clin Exp Dent 2017 Jul 1;9(7):e861-e868. Epub 2017 Jul 1.

Department of Clinical, Surgical, Diagnostic and Pediatric Sciences - Section of Dentistry. University of Pavia, Italy.

Background: The aim of the present study was to evaluate the protective effects of a zinc-hydroxyapatite toothpaste on repairing enamel erosion produced by a soft drink (Coca-Cola) compared to toothpastes with and without fluoride using Scanning Electron Microscopy (SEM).

Material And Methods: Fifty specimens were assigned to 5 groups of 10 specimens each. (Group 1: no erosive challenge, no toothpaste treatment, group 2: erosive challenge, no toothpaste treatment, 3: erosive challenge, toothpaste without fluoride, group 4: erosive challenge, fluoride toothpaste treatment, group 5: erosive challenge, zinc-hydroxyapatite toothpaste treatment). Repeated erosive challenges were provided by immersing bovine enamel specimens (10 per group) in a soft drink for 2 min (6mL, room temperature) at 0, 8, 24 and 32 h. After each erosive challenge, the toothpastes were applied neat onto the surface of specimens for 3 min without brushing and removed with distilled water. Between treatments the specimens were kept in artificial saliva. The surface of each specimen was imaged by SEM.

Results: Statistically significant differences were found between the samples used as control and those immersed in Coca-Cola (group 1 and 2): indeed among all groups the highest grade of damage was found in group 2. Instead the lowest grade was recorded in the samples of group 5 (Zinc hydroxyapatite toothpaste).

Conclusions: The results of this study confirmed the potential benefit the Zn-HAP technology could provide in protecting enamel from erosive acid challenges. The treatment of erosively challenged enamel with Zn-Hap toothpaste showed a clear protective effect. Dental erosion, enamel, SEM, toothpaste.
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http://dx.doi.org/10.4317/jced.53790DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5553346PMC
July 2017

Radiographic technical quality of root canal treatment performed by a new rotary single-file system.

Ann Stomatol (Roma) 2017 Jan-Mar;8(1):18-22. Epub 2017 Jul 3.

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, Section of Dentistry, University of Pavia, Pavia, Italy.

Aim: The aim of the present study was to evaluate radiographically the technical quality of root canal filling performed by postgraduate students with a new single-file Nickel-Titanium System (F6 Skytaper Komet) in clinical practice.

Methods: Records of 74 patients who had received endodontic treatment by postgraduate students at the School of Dentistry, Faculty of Medicine, University of Pavia in the period between September 2015 and April 2016 were collected and examined: the final sample consisted 114 teeth and 204 root canals. The quality of endodontic treatment was evaluated by examining the length of the filling in relation to the radiographic apex, the density of the obturation according to the presence of voids and the taper of root canal filling. Chi-squared analysis was used to determine statistically significant differences between the technical quality of root fillings according to tooth's type, position and curvature.

Results: The results showed that 75,49%, 82,84% and 90,69% of root filled canals had adequate length, density and taper respectively.

Conclusions: Overall, the technical quality of root canal fillings performed by postgraduates students was acceptable in 60,78% of the cases.
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http://dx.doi.org/10.11138/ads/2017.8.1.018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5507162PMC
July 2017

Discoloration of different esthetic restorative materials: A spectrophotometric evaluation.

Eur J Dent 2017 Apr-Jun;11(2):149-156

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences - Section of Dentistry, University of Pavia, Pavia, Italy.

Objective: A crucial property of esthetic restorative materials is their long-term color stability. The aim of this study was to evaluate the color stability of esthetic restorative materials (one microfilled flowable composite, one nanofilled composite, one nanoybrid composite, one microfilled composite, and one nanoybrid ormocer-based composite) after surface roughening with cola and exposure to different staining solutions (coffee and red wine).

Materials And Methods: All materials were polymerized into silicone rubber rings (2 mm × 6 mm × 8 mm) to obtain 150 specimens identical in size. Seventy-five specimens of Group A were first exposed to cola for 24 h, and then samples were immersed in coffee or red wine over a 28-day test period. A colorimetric evaluation, according to the CIE L*a*b* system, was performed at 7, 14, 21, 28 days. Shapiro-Wilk test and Kruskal-Wallis analysis of variance were applied to assess significant differences among restorative materials. Means were compared with Scheffe's multiple comparison test at the 0.05 level of significance.

Results: Specimens of Group A showed higher variations when compared with Group B's specimens ( < 0.05). After 28 days, the immersion protocols caused a clinically perceivable color change for all materials tested ( < 0.05). CeramX Universal and Admira Fusion showed the lowest ΔE variations ( < 0.05).

Conclusions: Staining beverages caused significant discolorations for all the materials tested. The first exposure to cola enhanced the subsequent staining with coffee or red wine. Nanohybrid composites reported the lowest color variations.
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http://dx.doi.org/10.4103/ejd.ejd_313_16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5502556PMC
July 2017

Color Stability of New Esthetic Restorative Materials: A Spectrophotometric Analysis.

J Funct Biomater 2017 Jul 6;8(3). Epub 2017 Jul 6.

Department of Clinical, Surgical, Diagnostic and Pediatric Sciences-Section of Dentistry, University of Pavia, Pavia 27100, Italy.

The aim of this in vitro study was to evaluate and compare the color stability of different esthetic restorative materials (one microfilled composite, one nanofilled composite, one nanoceramic composite, one microfilled hybrid composite, one microfilled hybrid composite, one nanohybrid Ormocer based composite and one supra-nano spherical hybrid composite) after exposure to different staining solutions (physiological saline, red wine, coffee). All materials were prepared and polymerized into silicon rings (2 mm × 6 mm × 8 mm) to obtain specimens identical in size. Thirty cylindrical specimens of each material were prepared. Specimens were immersed in staining solutions (physiological saline, coffee and red wine) over a 28-day test period. A colorimetric evaluation according to the CIE L*a*b* system was performed by a blind trained operator at 7, 14, 21, 28 days of the staining process. The Shapiro-Wilk test and ANOVA were applied to assess significant differences among restorative materials. A paired -test was applied to test which CIE L*a*b* parameters significantly changed after immersion in staining solutions. All restorative materials showed significant color differences after immersion in coffee. Coffee caused a significant color change in all types of tested composite resins. Only Filtek Supreme XTE demonstrated a staining susceptibility to red wine; no other significant differences among the materials were demonstrated. Long-term exposure to some food dyes (coffee in particular) can significantly affect the color stability of modern esthetic restorative materials regardless of materials' different compositions.
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http://dx.doi.org/10.3390/jfb8030026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618277PMC
July 2017

Influence of dentin pretreatment on bond strength of universal adhesives.

Acta Biomater Odontol Scand 2017 Jan 27;3(1):30-35. Epub 2017 Mar 27.

Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, Section of Dentistry, University of PaviaPaviaItaly.

The purpose of the present study was to compare bond strength of different universal adhesives under three different testing conditions: when no pretreatment was applied, after 37% phosphoric acid etching and after glycine application. One hundred and fifty bovine permanent mandibular incisors were used as a substitute for human teeth. Five different universal adhesives were tested: Futurabond M+, Scotchbond Universal, Clearfil Universal Bond, G-Premio BOND, Peak Universal Bond. The adhesive systems were applied following each manufacturer's instructions. The teeth were randomly assigned to three different dentin surface pretreatments: no pretreatment agent (control), 37% phosphoric acid etching, glycine pretreatment. The specimens were placed in a universal testing machine in order to measure and compare bond strength values. The Kruskal-Wallis analysis of variance and the Mann-Whitney test were applied to assess significant differences among the groups. Dentin pretreatments provided different bond strength values for the adhesives tested, while similar values were registered in groups without dentin pretreatment. In the present report, dentin surface pretreatment did not provide significant differences in shear bond strength values of almost all groups. Acid pretreatment lowered bond strength values of Futurabond and Peak Universal Adhesives, whereas glycine pretreatment increased bond strength values of G Praemio Bond adhesive system.
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http://dx.doi.org/10.1080/23337931.2017.1305273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5463333PMC
January 2017

Color stability of esthetic restorative materials: a spectrophotometric analysis.

Acta Biomater Odontol Scand 2016 Dec 10;2(1):95-101. Epub 2016 Aug 10.

Department of Clinical-Surgical, Diagnostic and Pediatric Sciences - Section of Dentistry, University of PaviaPaviaItaly.

The aim of this study was to evaluate the color stability of different restorative materials (one microfilled composite, one nanofilled composite, one nanohybrid composite and one Ormocer-based composite) after exposure to different staining solutions (coffee, coca-cola and red wine). All materials were polymerized into silicon rings (2 mm ×6 mm ×8 mm) to obtain specimens identical in size. Thirty cylindrical specimens of each material were prepared. They were immersed in staining solutions over a 28-day test period. A colorimetric evaluation according to the CIE system was performed by a blind trained operator at 7, 14, 21, 28 days of the staining process. The Shapiro-Wilk test and Kruskal-Wallis ANOVA were applied to assess significant differences among restorative materials. The paired -test was applied to test which CIE parameters significantly changed after immersion in staining solutions. All restorative materials showed clinically perceptible color differences after immersion in coffee. and values showed the highest variability. Coca cola and red wine did not influence the color stability for all restorative materials except for Filtek Supreme XTE. Coffee caused a significant color change in all types of tested composite resins. Filtek Supreme XTE demonstrated alone a staining susceptibility to red wine; no other significant differences among the materials were demonstrated. Long-term exposure to some food dyes (coffee in particular) can significantly affect the color stability of modern esthetic restorative materials regardless of materials' different composition.
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http://dx.doi.org/10.1080/23337931.2016.1217416DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5433231PMC
December 2016