Frontiers in Restorative Dentistry Biomaterials and Endodontic Instruments.

Restorative dentistry deals with the prevention, diagnosis, and treatment of pathological conditions affecting the teeth, to restore their function and aesthetics [...].

Restorative Materials Exposed to Acid Challenge: Influence of Temperature on In Vitro Weight Loss.

Consumption of acidic beverages and foods could provoke erosive damage, both for teeth and for restorative materials. Temperatures of consumption could influence the erosive effects of these products. The aim of this in vitro study is to assess the influence of an acidic challenge on the weight loss of different restorative materials. Resin composites and glass-ionomer cements (GIC) were tested. The medium of storage was Coca-Cola (Coca-Cola, Coca-Cola Company, Milano, Italy) at two different temperatures, 4 and 37 °C, respectively for Group A and Group B. For each group, nine specimens were prepared for each material tested. After 7 days, weight was assessed for each sample, and the percentage weight loss was calculated. For all the resin composites (Groups 1−13), no significant weight losses were noticed. (<1%). Conversely, GICs (Groups 14 and 15) showed significant weight loss during the acidic challenge, which was reduced in the case of these materials that included a protective layer applied above. Significant differences were registered with intra-group analysis; weight loss for specimens immersed in Coca Cola at 37 °C was significantly higher for almost all materials tested when compared to specimens exposed to a cooler medium. In conclusion, all the resin composites showed reliable behaviour when exposed to acidic erosion, whereas glass-ionomer cements generally tended to solubilize.

Influence of Enamel Exposure to Acidic Drink on Shear Bond Strength of Different Fissure Sealants.

In the present study, we evaluated the influence of bovine enamel exposure to acidic drinks (Coca-Cola, Coca-Cola Company, Milano, Italy, pH = 2.37) on shear bond strength of three sealants (Fissurit; Grandio Seal and Admira Fusion-Voco Gmbh, Cuxhaven, Germany). For each sealant, two adhesive techniques were tested to investigate the impact of the adhesive application on shear bond strength of sealants after immersion in acidic drink and in the control: Group 1-Control: enamel surface was not in contact with acid drinks, acid etching application and self-adhesive technique for fissure sealant; Group 2-enamel surface was not in contact with acid drinks, acid etching, and adhesive applications, an etch-and-rinse technique for fissure sealant; Group 3-enamel surface was immersed in acid drink, acid etching application and self-adhesive technique for fissure sealant; Group 4-enamel surface was immersed in acid drink, acid etching, and adhesive applications, an etch-and-rinse technique for fissure sealant. For each specimen, the sealant composite resin was applied to the enamel surface and tested with a universal testing machine. Shear bond strength was measured in MPa and with an optical microscope to determine failure modes, quantified with adhesive remnant index (ARI). Enamel acidification variably influenced bond strength values of the different sealants. When no enamel pretreatment was applied, no significant differences were found among the sealants (p > 0.05). However, the mere application of acid etching without adhesive procedures resulted in lower bond strength (p < 0.001). The acid pretreatment affected significantly the bond strength of all sealants tested (p < 0.001), but no significant differences were recorded between the subgroups.

Ozone Gel in Chronic Periodontal Disease: A Randomized Clinical Trial on the Anti-Inflammatory Effects of Ozone Application.

The search for new topical treatments able to display not only antimicrobial properties but also a multiplicity of other beneficial effects while expressing safe cytocompatibility toward host tissues is being progressively developed. Antiseptics represent an aid to the gold standard nonsurgical treatment Scaling-and-Root-Planing (SRP) for periodontal disease. This split-mouth study aims to assess the efficacy of the ozonized gel GeliO3 (Bioemmei Srl, Vicenza, Italy) plus SRP (experimental treatment), with respect to SRP + chlorhexidine gel. Ten participants were treated with SRP + chlorhexidine gel (control sites) and with SRP + ozone gel (trial sites). After 1 (T1) and 3 months (T2) from baseline (T0), patients were revisited. At each time-point, the following indexes were assessed: probing pocket depth (PPD), clinical attachment level (CAL), gingival index (GI), plaque index (PI), and bleeding on probing (BoP). It has been assessed that the use of the ozonized gel in addition to SRP did not show significant differences if compared to conventional SRP + chlorhexidine. Chlorhexidine was found to be more effective than ozone in reducing CAL and GI at T2. Ozone deserves consideration for its wide applicability in several clinical fields. In this connection, we also glance at the latest research on ozone therapy.

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

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 × 104) 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 p < 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.

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

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 (p > 0.05), whereas for subgroups C, only GXT and VCB showed significantly lower values (p < 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 (p > 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.

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

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.

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

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 Candida 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 Candida strains are resistant to antifungal drugs. The aim of this preliminary analysis is to evaluate the antimycotic efficacy of a new ozonided oil (GeliO3), 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 Candida species: C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, 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 Candida infections. Moreover, useful applications could be used to counteract Candida colonization of endosseous implants.

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

The current in vitro 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.

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

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.

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

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.

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

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 (P < 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.

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

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.

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

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.

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

BACKGROUND: The purpose of this in vitrostudy 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 (p<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. Key words:Enamel, erosion, protective agents, soft drinks, toothpastes.

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

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 in vitro 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. Post hoc comparison was done using Tukey's honestly significant difference test. Significance for statistical tests was predetermined at P < 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.

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

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 P < 0.05. RESULTS: Kruskal-Wallis analysis of variance (ANOVA) for debris score showed significant differences among the Ni-Ti systems (P < 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.

Cytotoxicity evaluation of a new ozonized olive oil.

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 (P < 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.

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

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 Streptococcus mutans was cultured and deposited onto each material, and the adhesion was evaluated through the colony-forming units determination. One-way ANOVA and Bonferroni's post hoc tests were applied to estimate significant differences between the esthetic materials. RESULTS: The highest amount of S. mutans 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 S. mutans 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.

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

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 Streptococcus mutans 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 (P<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 S. mutans (P<0.05); on the contrary, Constic increased up to ~4 times the bacterial adhesiveness respected to the untreated control (P<0.05). Key words:Acidic drinks, bacterial adhesion, fissure sealants, Streptococcus mutans.