Hemoglobin Detroit: beta95 (FG2) lysine leads to asparagine

Hb Detroit is a mutant which migrates between Hb A and Hb J Baltimore on cellulose acetate (pH 8.5), and with Hb A on citrate agar (pH 6.0). Globin chain analyses in alkaline and acid buffers reveal an abnormal beta chain with a mobility between the betaA and betaJ Baltimore chains. Structural characterization of this abnormal chain shows that lysine at position 95 is replaced by asparagine. No hematological abnormalities could be attributed to the presence of the mutant, and the oxygen affinity properties of the stripped hemoglobin are similar to those of Hb A. The beta95 residue which is substituted in Hb Detroit and also in Hb N Baltimore ((beta95 Lys leads to Glu) does not appear to be in a critical functional area of the molecule.

The Influence of Abrasive and Acidic Aggressions on the Surface Condition of Flowable Composite Resin

The aim of this in vitro study was to evaluate the effect of hydrochloric acid associated with the abrasive effect of toothbrushing on the surface condition of three flowable composite resins used for direct restoration. Seventy samples of each composite resin: Grandio Flow (VOCO, Germany)—group A, Filtek Ultimate Flow (3M-ESPE, MN, USA)—group B, G-aenial Flo X (GC Europe)—group C were prepared, submersed in hydrochloric acid 30% for 60 min and then submitted to simulated toothbrushing procedure using 5000 cycles with toothbrushes with medium and hard bristles, immediately after the chemical attack, after 30 min or without any chemical attack. The sample’s surface roughness was analyzed using a noncontact profilometer (Dektak XT, Bruker, USA). ANOVA and post hoc Bonferroni tests, with a p < 0.05, were used to analyze the values. Hydrochloric acid action for 60 min and six months of toothbrushing using toothbrushes having medium hardness or firm bristles affects the surface roughness of tested flowable composite resins. Toothbrushing with firm bristles immediately after acidic challenge determines increased surface roughness for two of the three flowable composite resins (Grandio Flow and Filtek Ultimate Flow). Toothbrushing with medium or firm bristles thirty minutes after the acidic aggression determine no effect on surface condition of flowable composite resins.

Customized 3D-Printed Titanium Mesh Developed for an Aesthetic Zone to Regenerate a Complex Bone Defect Resulting after a Deficient Odontectomy: A Case Report

Background and Objectives: Alveolar ridge augmentation in the complex bone defect is a popular topic in implantology. Guided bone regeneration (GBR) is one of the most commonly applied methods to reconstruct alveolar bone. The application of a membrane is the fundamental principle of GBR. There are many membrane types used in oral surgery, but the advantage of the titanium mesh is the rigidity which provides space maintenance and prevents contour collapse. The smooth surface also reduces bacterial contamination. Using computer-aided design (CAD) and computer-aided manufacturing (CAM) in dentistry allows us to obtain the perfect architecture form of the mesh, which covers and protects the bone reconstruction. Case presentation: We present a surgical case of a 27-year-old female patient with severe aesthetic bone atrophy after a deficient odontectomy. Based on the GBR clinical applications, the technique consists of bone reconstruction and a customized titanium mesh application. Using mesh titanium in this case presentation was a reliable alternative to perform a lateral alveolar bone augmentation and reconstruct ridge deformities before reaching an ideal implant placement. Conclusions: According to our case report, the customized titanium mesh could be a valuable option for guided bone regeneration in aesthetic maxillary defects.

A European Core Curriculum in Cariology: the knowledge base

This paper is part of a series of papers towards a European Core Curriculum in Cariology for undergraduate dental students. The European Core Curriculum in Cariology is the outcome of a joint workshop of the European Organization for Caries Research (ORCA) together with the Association for Dental Education in Europe (ADEE), which was held in Berlin from 27 to 30 June 2010. This paper presents a closer look at the knowledge base as presented in the European Core Curriculum in Cariology. It comprises not only traditional basic sciences, such as anatomy and histology, but also emerging sciences such as molecular biology and nanotechnology and also fields such as behavioural sciences and research methodology. The different supporting competences are elaborated and explained. The problems of implementing a curriculum that truly integrates this foundation knowledge into the clinical teaching are discussed.

Evaluation of Pre-heating Effects on Marginal Adaptation of Resin-based Materials

The aim of the study was to compare the marginal adaptation of three different resin-based materials used for direct restoration: hybrid composite resin (Gaenial Posterio, GC Corporation), a compomer (Dyract eXtra, Dentsply Sirona), and a giomer (Beautifil II, Shofu Dental) applied at room temperature or after preheated at preheating 50 and 60oC. Class II cavities were prepared on proximal surfaces of extracted teeth and randomly divided in 3 groups according to the material used for restoration. In each group five cavities were restored using the materials at room temperature (subgroup 1), five cavities were restored using preheated materials at 50şC (subgroup 2), and five cavities were restored using preheated materials at 60şC (subgroup 3). The teeth were stored in distilled water for 14 days and then were immersed in 2% methylene blue buffered dye solution (pH = 7) for 4 hours. The teeth were transversally cut and the sections were examined using optical microscope (Carl-Zeiss AXIO Imager A1m) at 50x magnification and the dye penetration was evaluated according to 4 scores. Decreased microleakage and fewer gap formation were recorded for all filling materials after they have been heated at 50 or 60oC. Pre-warming of resin-based materials improves the adaptation of these materials to tooth structures.

Studies on Adhesion of Composite Resins and Glass-Ionomer Cements in Open-Sandwich Technique

The aim of this study was to assess the quality of the interface between dental root cement and some restorative materials used in the open sandwich technique. Standardised cavities were prepared on the buccal and oral surfaces of 30 human molars with the gingival margin situated in root cement. The teeth were randomly divided in 3 groups. Different materials combinations were used in buccal and oral cavities. In the control group, the cavities were filled only with composite resins (Filtek Z250-3M ESPE and Zmack Comp-Zermack). In the test groups the cavities were restored using an open sandwich technique as follows: in group 1 Filtek Z250 in combination with Dyract, respectively Ketac Molar Easymix; in group 2 Zmack Comp in combination with Dyract, respectively Ketac Molar. The teeth were stored in 1% methylene blue solution, for 24 hours. The samples were longitudinally sectioned through the centre of restorations and the degree of dye penetration as well as the morphology of the interface between the root cement and the restorative material were evaluated by optical microscopy and SEM. The results showed less microleakage and and adhesive failures in open sandwich restorations with Zmack Comp and Dyract combination.

Detection and Assessment of Interleukin 6 in Irreversible Pulp Inflamation

The study aimed to assess the number, localization and distribution of interleukin 6 (IL-6) positive cells in healthy pulp, acute and chronic pulpitis. The study group included 48 patients aged between 18-72, treated in University of Medicine and Pharmacy Grigore T. Popa Iasi, Romania. The pulpectomy was performed on 42 patients diagnosed with acute and chronic pulpitis. The other 6 patients, without signs of dental caries or periodontal disease, were submitted to extractions of teeth for orthodontic purposes, with pulpectomy performed before extraction. The pulp samples were examined with optic microscope. The detection and assessment of IL-6 were performed using immunohistochemical technique. Data were statistically analysed using non-parametric tests. According to morphopathological criteria, 42.85% were classified as acute pulpitis and 57.14% as chronic pulpitis. The pulp samples in control group were not associated with IL-6 positive cells. The analysis of all samples with acute and chronic pulpitis identified 73.80% samples with IL-6 and 26.20% associated with the absence of IL-6. The highest frequency of IL-6 positive cells was recorded in rich-cell zone of crown dental pulp. The systemic distribution of IL-6 positive cells was mostly diffused without well-defined orientation. IL-6 release in acute and chronic pulpitis is significantly higher comparing with healthy pulp tissue.

Influence of the Loading with Newly Green Silver Nanoparticles Synthesized Using Equisetum sylvaticum on the Antibacterial Activity and Surface Hardness of a Composite Resin

The aim of the study was to evaluate the antibacterial activity and surface hardness of a light-activated microhybrid composite resin modified with green silver nanoparticles (AgNPs). AgNPs were synthesized using an Equisetum sylvaticum extract and characterized through different methods such as UV-Vis, EDX, and FTIR. The obtained AgNPs were mixed with a microhybrid composite resin (Herculite XRV, Kerr Corp., Orange, CA, USA) in different concentrations: 0% (group A-control); 0.5% (group B); 1% (group C); and 1.5% (group D). A total of 120 composite resin disk-shaped samples were obtained and divided into 4 groups (n = 30) according to AgNP concentration. Each group was then divided into 2 subgroups: subgroup 1-samples were not soaked in 0.01 M NaOH solution; and subgroup 2-samples were soaked in 0.01 M NaOH solution. The antibacterial activity against Streptococcus mutans was determined using a direct contact test. A digital electronic hardness tester was used to determine the composite resin's Vickers surface hardness (VH). Statistical analysis was performed using the Mann-Whitney U and Kruskal-Wallis nonparametric tests with a confidence level of 95%. Groups C and D showed higher antibacterial activity against S. mutans when compared to the control group (p < 0.05). No significant differences were recorded between VH values (p > 0.05). The use of AgNPs synthesized from Equisetum sylvaticum as a composite resin filler in 1% wt. and 1.5% wt. reduced the activity of Streptococcus mutans. Soaking of the experimental composite resin decreased the antibacterial efficacy. The loading of a microhybrid composite resin with AgNPs in concentrations of 0.5% wt., 1% wt., and 1.5% wt. did not influence the surface hardness.

Effect of Dental Bleaching on Marginal Sealing of Composite Resin Restorations Bonded with a Universal Adhesive

The aim of this study was to evaluate the postoperative effect of one bleaching agent containing 40% peroxide hydrogen on the interface between dental tissues and a microhybrid composite resin bonded with a universal adhesive applied in total-etch and self-etch technique. Standardized Class V restorations were performed in oral surfaces of 40 extracted human molars with the gingival margins placed bellow the cement-enamel junction. For 20 restorations the adhesive was applied with preliminary etching and for the others the adhesive was applied by using the self-etch technique. Half of the samples of each group were bleached using Opalescence Boost in one session 20 minutes-application. The sealing quality of both enamel and cervical margins of the restorations was evaluated using a microleakage test by immersion in 1% methylene blue for 24 hours. The microleakage scores were assessed using an optical microscope and the data were statistically analyzed. No statistical significant differences were recorded between the bleached and control groups and between the study groups according to the etching strategy used for bonding.

The Effect of Three Desensitizing Toothpastes on Dentinal Tubules Occlusion and on Dentin Hardness

There are two main methods used for dentin hypersensitivity (DH) treatment: dentinal tubule occlusion and blockage of nerve activity. Dentifrices are the most common vehicles for active ingredients used for DH treatment. The aim of this study was to evaluate the efficacy of three toothpastes on dentinal tubule occlusion, mineral acquisition, and dentin hardness. Forty human dentin disks were submerged in 40% citric acid for 30 s and then exposed to tooth brushing for 2 min twice a day for 14 days using three toothpastes: Dontodent Sensitive (group 1), Dr. Wolff's Biorepair (group 2), and Sensodyne Repair and Protect (group 3). In the control group (group 4), the samples were brushed with water. All of the samples were evaluated using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Vickers dentin hardness determination. On SEM images, the degree of dentinal tubule occlusion was assessed using a five-grade scale. The mean score values in groups 1-4 were 3.60 ± 0.69, 2.20 ± 0.91, 2.30 ± 1.16, and 5.00 ± 0.00, significantly higher in study groups when compared to the control group (Kruskal Wallis test p < 0.05). EDX evaluation showed significantly higher calcium and phosphorus concentrations in groups 1 and 3 when compared to control group d. The mean values of Vickers dentin hardness numbers in groups 1-4 were 243.03 ± 10.014, 327.38 ± 56.65, 260.29 ± 37.69, and 225.83 ± 29.93, respectively. No statistically significant results were obtained when comparing the hardness mean values in groups (Kruskal-Wallis statistical test, p = 0.372 > 0.05). All three toothpastes tested demonstrated significant occlusion of dentinal tubules. Dontodent Sensitive and Sensodyne Repair and Protect toothpastes enhanced the calcium and phosphorus content of the dentin surface. None of the toothpastes increased dentin hardness as a result of mineral acquisition.

The Impact of Simulated Gastric Acid and Toothbrushing on Surface Characteristics of Resin-Modified Glass-Ionomer Cements

Background and Objectives: The aim of this in vitro study was to evaluate the effect of simulated gastric acid associated with toothbrushing on the surface condition of three resin-modified glass-ionomer cements (RMGIC). Materials and Methods: One hundred and sixty samples of each material were obtained and included in three study groups according to the tested material: Group I (Ionolux, VOCO GmbH, Cuxhaven, Germany); Group II (Vitremer, 3 M-ESPE, St. Paul, MN, USA); and Group III (Fuji II LC, GC Corporation, Tokyo, Japan). The samples were submersed in hydrochloric acid 0.01 M (pH 3.8) for 3 h and exposed to a toothbrushing procedure at a frequency of 10,000 cycles with medium and hard bristles immediately or 30 min after the acid attack. Profilometric measurements were performed by using a non-contact profilometer (Dektak XT, Bruker, Billerica, MA, USA) in order to assess the surface roughness. ANOVA and Bonferroni post hoc tests were used for the statistical analysis at a significance level of p < 0.05. Results: Exposure of RMGICs to the erosive effect of hydrochloric acid in association with toothbrushing 30 min after the chemical attack increased the surface roughness of all three RMGICs. Exposure of the three tested materials exclusively to the action of hydrochloric acid did not affect the surface roughness. Conclusions: One year of hydrochloric acid challenge associated with one year of toothbrushing with medium-hardness bristles performed 30 min after the acid attack increase the surface roughness of two of the three types of RMGIC tested (Ionolux and Fuji II LC).

Study Regarding the Capacity of Self-assembling Peptides to Remineralize the Acute and Chronic Incipient Caries Lesions

The aim of the study was to evaluate the effect of biomimetic self assembling peptides (P11 -4) on remineralization of acute and chronic incipient enamel lesions by microhardness analysis. Ten extracted permanent human teeth having incipient white spot lesions and ten extracted teeth with brown spot lesions on proximal surfaces were included in this study. Half of the extern surface of the lesions was covered with flowable composite resin (Vertise flow, Kerr Corporation) and served as negative control site. On the other half Curodont� Protect gel (Credentis AG, Windisch, Switzerland) was applied 2 times a week, 8 weeks (study). The teeth were cut mesio-distally using diamond disks under cooling water, perpendicularly to the extern surface of the lesions, in order that both areas (negative control and study) to be evaluated. The opposite proximal sound enamel on each section served as positive control. The subsurface microhardness of the enamel samples was determined using digital microhardness tester (MicroVickers Hardness System CV- 400DMTM, CV Instruments Namicon). On horizontal tooth sections indentations were made at 25�m (A1), 75 �m (A2), 125 �m (A3), 175 �m (A4), 225 �m (A5), and 275 �m (A6) bellow the extern surface of the lesions. For white spot and brown spot caries lesions, in both negative control and study groups, the VHN values increased from A1 to A6 areas. In study group VHN values were higher than in negative control group irrespective of the area of examination. The lowest VHN value was registered in negative control A1 area and the highest in study group A6 area. In all six areas of investigation, VHN values in negative control and study groups were lower than the values in positive control group. The use of self-assembling peptides on white spot and brown spot caries lesions increase the hardness of these lesions in the deeper layers of the lesions.

Evaluation of Dentinal Changes Following Application of Three Different Desensitizing Agents

The aim of this in vitro study was to evaluate the effect of three desensitizing tooth pastes on the dentinal tubule occlusion. Thirty dentin discs having a thickness of 3 mm were obtained by cutting human teeth. The discs were submersed in citric acid for 30 seconds to open the dentin tubules. Then the discs were cut in two halves. In each group 10 halves were kept in 0.9% NaCl solution) and the other 10 halves were exposed to the action of one of the tested desensitizing toothpastes. The dentin samples were placed in the machine designed to simulate tooth brushing. Three commercial desensitizing toothpastes were chosen to be applied on dentin surface. The morphology of dentin samples and the level of tubule occlusion was scored using scanning electron microscope. All the three desensitizing toothpastes demonstrated significant effects on dentinal tubule occlusion. The tooth paste containing arginine and calcium carbonate as active ingredients showed the highest degree of tubule occlusion, followed by the dentifrice containing strontium acetate and sodium fluoride.

Comparative Evaluation of Hardness and Elasticity Modulusof Tooth-Colored Materials for Dental Restoration

The aim of this study was to compare Rockwell hardness (HRC) and modulus of elasticity (Young modulus) to different restorative materials. Three commercial composite resins: Filtek Z250 (3M ESPE Co.), Zmack Comp (Zermack SpA, Italy), Kalore (GC Corporation, Japan) and one compomer: Dyract eXtra (Dentsply De Trey Gmbh, Germany) were used. Six samples of each material were obtained by placing them in plastic rings having 5 mm inner diameter and 6 mm high. All composite samples were cured for 40 s using a lamp LEDidition - Ivoclaire Vivadent clinical, Austria. The samples were finished and polished and then stored in distilled water, at room temperature for 48 hours. Rockwell Hardness (HRC) measurements were realized using the UMT-2 Tribometer (CETR). The hardness was automatically calculated from the slope of unloading curve and expressed in GPa and transformed in HRC values (kgf/mm2). Six indentations were performed on diametral direction and mean values were calculated for all tested samples. The device also measured the modulus of elasticity for each sample. Data were analyzed by ANOVA and Mann-Whitney test (significance level of p [ 0.05). The mean HRC values were the following: Filtek Z250 ] Zmack Comp ] Dyract eXtra ] Kalore (82.98 ] 70.10 ] 53.27 ] 37.72 kg/mm2). Regarding Young modulus, the rank from highest to lowest as follows: FiltekZ250 ] Zmack Comp ] Dyract eXtra ] Kalore (16.24 ] 14.05 ] 12.41 ] 7.86). The microhydrid composite resins have a significantly higher hardness than nano-hybrid composites or compomers.

Study Regarding the Effect of Some Remineralizing Products Used in the Treatment of Erosion Induced by Sport Drinks

The aims of the study were to evaluate and to compare the effects of some commercial sport drinks on enamel and dentine when using remineralizing products before the use of these beverages. Enamel and dentine fragments were immersed five times, 3 min each during 2 h, fourteen days, in three sport drinks: Gatorade beverage (PepsiCo), Isostar (Isostar) and Cyto Max (CytoSport). On other tooth fragments three remineralizing products were applied before the immersion in sport drinks: Colgate Total� toothpaste (Colgate Company), a fluoride gel (Densell Company), and MI Paste Plus product (GC Company). In all the samples the enamel and dentine hardness were determined using a digital device CV 400 DAT (Namicon). Gatorade beverage leaded to the highest demineralization of the enamel and dentine, followed by Isostar and CytoMax. All three remineralizing products used before the acid attack determined increased values of enamel and dentine hardness when compare to the values obtained when only the acidic beverages were applied. The highest enamel and dentine protection were recorded when MI Paste Plus product was applied, followed by fluoride gel and toothpaste products.

Assessment of Near-Infrared (780nm) Light Transillumination Accuracy for Detection of Incipient Caries Lesions

The aim of study was to evaluate the accuracy of the near-infrared light transillumination technique used in the detection of the proximal incipient dental caries. The study was performed on 12 medium caries risk subjects (mean age of 26.5). A total number of 312 proximal dental surfaces from the posterior dental group were included in the study. All the proximal surfaces, which had not been restored, or unaffected by cavitated dental caries, were assessed by a near-infrared transillumination camera system using light with a 780nm wavelength (DIAGNOcam, KaVO). Bitewing radiographies were performed for all patients included in study. Visual and tactile examination after tooth separation was performed as gold standard to detect the incipient proximal dental caries (ICDAS scores 02 and 03). Statistical analysis using Chi-square test was performed to compare the diagnostic performance of near-infrared light transillumination and the bitewing radiography. Near-infrared light transillumination showed higher sensitivity (81.80%) when compared to bitewing radiography (65.90%) to detect the non-cavitated proximal enamel caries (ICDAS score 02). Near-infrared light transillumination method showed higher sensitivity (100%) when compared to bitewing radiography (81.50%) to detect the incipient cavitated proximal enamel caries (ICDAS score 03). Specificity values for proximal incipient dental caries (ICDAS codes 02 and 03) were 95.03% for near-infrared light transillumination and 99.18% for bitewing radiography. DIAGNOcam (KaVO) is a reliable tool with high diagnostic accuracy of the incipient dental caries localized on proximal surfaces of the posterior dental group.

Assessment of Physical and Chemical Parameters of Four Endodontic Sealants

The endodontic sealants have an essential role in the root canal filling. The aim of this study was to analyse and compare three physio-chemical properties (pH, solubility, viscosity). The most significant decrease of the viscosity was for MTA-Fillapex, followed by Endoflas FS and Acroseal. The best behavior was recorded for Endomethasone N. The total decrease of dry mass (reported to baseline) was 0.0113 for Acroseal. Endoflas FS had a total decrease of dry mass of 0.0377 (from 0,6864 to 0.6487) during the study. The total decrease of dry mass (reported to baseline) was 0.0047 for Endomethasone N. MTA Fillapex had a total decrease of 0.0226 (from 0.4805 to 0.4579) during the study period. MTA Fillapex had the highest pH values (pH 10.16), followed by Acroseal (pH 8.79), Endoflas FS (pH 7.98) and Endomethasone N (pH 7.73).

The Influence of Chlorhexidine Gluconate Dentine Pre-Treatment on Adhesive Interface and Marginal Sealing

Background and Objectives: The aim of this in vitro study was to evaluate the combined effect of a 2% chlorhexidine aqueous solution and a universal adhesive system applied in self-etch and etch-and-rinse strategies on the composite resin-dentin interface. Materials and Methods: Class V cavities were prepared on the facial and lingual surfaces of forty caries-free molars extracted for orthodontic reasons. The samples were randomly divided into two groups corresponding to the used etching protocol: I-etch-and-rinse; II-self-etch. In each tooth, one cavity was assigned for the control subgroups -IA (n = 20) and IIA (n = 20)-adhesive only, and the opposite cavity was pretreated with a 2% chlorhexidine solution-Gluco CHeX Cerkamed-subgroups IB (n = 20) and IIB (n = 20). Both sets of groups were restored using a universal adhesive system (Single Bond Universal Adhesive, 3M-ESPE) and a bulk-fill composite resin (Filtek One Bulk Fill Restorative, 3M-ESPE). The roots and the pulp tissue were then removed, and a needle connected to a perfusor with 100 mL saline solution was used for pulp pressure simulation with a hydrostatic pressure of 20 cm H₂O. Cariogenic attack was simulated using a demineralizing solution for 3 days at a constant temperature of 25 °C. The teeth were then sectioned in a facial-lingual direction and the microleakages at the occlusal and cervical margins were registered and scored using an optical Carl-Zeiss AXIO Imager A1m microscope (Carl-Zeiss). The composite resin-dentin interface was analyzed using a SEM Vega Tescan LMH II. Statistical analysis was performed using the Kruskal-Wallis test with a significance level of p < 0.05. Results: Microleakage evaluation showed no significant differences among the study groups (p > 0.05). In subgroup IA, significant differences were recorded between occlusal and cervical margins (p < 0.05). Conclusions: Application of chlorhexidine on tooth substrate before using a universal bonding system in total etch or self-etch mode has no influence on the adhesive interface in the condition of cariogenic attack. The thickness of the adhesive resin layer seems to be less uniform when using chlorhexidine, but the morphological differences at the adhesive interface have no influence on the sealing capacity of the universal bonding system, regardless of the etching strategy.

[The influence of hygroscopic expansion on nanohybrid composite restorations]

Hygroscopic expansion of resin materials is a common phenomena due to water adsorption into the resin matrix. This expansion is dependent upon the chemical structure of the material. Water sorption of resin dental material may contribute to stress release immediately after polymerization shrinkage has occurred. The aim of this study was to evaluate the influence of water storage on nanohybrid composite by assessment of marginal enamel sealing of restorations.

MATERIAL AND METHOD

30 human teeth extracted for periodontal or orthodontic reasons were used in these study. Cavities were prepared and restored using a nanohybrid composite (Ceramix Mono, Dentsply DeTrey) and a total-etch adhesive system (Prime&Bond NT, Dentsply DeTrey). The teeth were then randomly divided in three groups which were stored for various times in deionized water (one hour, 24 hours and 7 days). After the storage period, the teeth were immersed in methylen blue 1% for 24 h. Then specimens were axially cut and the dye penetration within the occlusal enamel interface was evaluated using optic microscope.

RESULTS

Kruskal-Wallis test showed significant differences of dye penetration between the long-term hydrated groups and the group hydrated for only one hour (p < 0.05). The mean value of dye penetration decreased from 0.04 mm to 0.1 mm after water storage for both 24 hours and 7 days. However, good sealing in enamel margins of restorations was observed even without hydration.

CONCLUSION

Our results confirm that nanohybrid composites used with total etch adhesives systems have good ability to seal the enamel margins and water sorption can improve this sealing.

Effects of Acidic Challenge on Demineralized Root Surface Treated with Silver Diamine Fluoride and Potassium Iodide

BACKGROUND

The aim of the study was to assess the protective effect of applying potassium iodide (KI) over silver diamine fluoride (SDF) on demineralized root dentin in the case of a sustained acidogenic attack.

METHODS

Forty caries-free third molars were used in the study. A diamond disc was used to separate the roots and the tooth crowns from the roots. Each root fragment was randomly distributed in one of the four study groups: C-samples were not demineralized; DD-demineralized samples; RS1-demineralized samples covered with SDF+KI (RS-Riva Star product, SDI limited, Bayswater, Australia); RS2-demineralized samples covered with SDF+KI and submersed to another acidic challenge for 3 days. SEM and EDX were used for the morphological and elemental analysis. Vickers hardness assessment was performed using a tribometer CETR UMT-2 (Bruker Corporation, Berlin, Germany). One-way ANOVA and post hoc Bonferroni tests were used for the statistical analysis with a significance level of p < 0.05.

RESULTS

Morphological and elemental changes were observed on the surface of the study samples. Significant differences were observed between the recorded hardness values of groups C and DD (p = 0.005), C and RS2 (p = 0.002), DD and RS1 (p = 0.011); RS1 and RS2 (p = 0.004).

CONCLUSIONS

The application of SDF and KI (Riva Star product) on root dentin caries resulted in the formation of a heterogeneous outer layer that sealed the dentin and increased the microhardness of the treated surface. In the conditions of the present study, this layer did not provide enough protection for root dentin exposed to continuous attacks.

Evaluation by Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy of the Effects of Root Canal Instrumentation on the Radicular Dentine

One area of technological advancement has been the shift from stainless steel hand tools to nickel-titanium (Ni-Ti) rotary tools. This paper aims to perform an in vitro comparative study to evaluate the efficacy of five endodontic manual and rotary instruments such as Kerr files, Orodeka Plex V, ProTaper Flydent NiTi super files, and ProTaper Flydent NiTi super files in combination with an ultrasonic endodontic E3D Diamantata EMS scaler used for root canal shaping. The following aspects were highlighted: effective removal of smear layer (SL) from the dentinal tubules in the coronal 1/3, middle 1/3, and apical 1/3 of the root canal, appearance of cracks in the dentinal walls by SEM analysis, and highlighting of dentin mineral content and remnant debris by EDX analysis. In the study, 48 monoradicular, uninjured teeth were taken and divided into four groups, each with 12 teeth to be canal modeled, then longitudinally sectioned; the active surface was metallized for SEM-EDX analysis. From the SEM micrograph analysis, the morphology of the crystallites, the distribution of SL components, and the highlighting of instrumentation path traces/amplitudes were observed. By analyzing the SEM photomicrographs at 750 and 800× magnification, it was possible to highlight the cracks in the root dentinal walls. Thus, in comparison with Lots I and II which did not present cracks, in Lot III multiple cracks of the root dentinal walls were identified, especially in the coronal 1/3, and in Lot IV cracks were present with preponderance in the coronal and apical 1/3 of the root canals. The EDX images with atom mapping show very well the rather homogeneous elemental distribution for Ca, N, and P, respectively inhomogeneous for Na, Ca, Si, C, N, O, and P elements, as a result of the presence of remnant products from the processing of the root dentinal walls. Root canal instrumentation performed with both manual Kerr needle instrumentation by a convection technique and the rotary, Orodeka system, by crown-down technique, resulted in minimal SL formation in all three root canal areas, unlike the ProTaper FlyDent system. Most cracks were recorded in the case of the ProTaper Flydent rotary instruments and the one in which it was paired with a diamond ultrasonic scaler. The occurrence of dentinal cracks causes a decrease in dentinal microhardness, favoring the occurrence of root fractures.

Evaluation of Compressive Strength of Repaired Direct Composite Resin Restorations

The aim of the study was to evaluate and to compare the compressive parameters of repaired composite restoration when using different types of composite resins and a universal bonding agent as an intermediate layer. Aged micro-filled hybrid and nano-filled hybrid composite resins were chosen to simulate old restoration. The same micro-filled hybrid composite resin was used as a repair material. A universal bonding agent applied in etch-and-rinse and self etch strategies was used as an intermediate layer in restoration repair. Non-aged composite resins were considered as control. Compressive strength and compressive modulus were determined by evaluating the samples in a universal testing machine. Lower values of the tested parameters were recorded after aging both types of composite resin when compared to control. Higher values of compressive strength were recorded when nano-filled hybrid composite resin was repaired when compared to micro-filled hybrid composite resin. The strategy of universal bonding agent application as an intermediate layer did not influenced the compressive properties of repaired restoration.

Evaluation of Rremineralization Capacity of Non-fluoride Home Products

The aims of the study were to characterize enamel, dentine and cementum surface aspect after using non-fluoride remineralization toothpastes containing calcium carbonate and calcium glycerophosphate by SEM evaluation, to determine chemical composition of enamel, dentin and cement after remineralization products application by EDX assessment, and to compare the remineralization capacity of the tested products. Ten extracted teeth having no dental caries, erosive or wear lesions were selected for the study. The teeth were split bucco-lingually and mesio-distally in four pieces. A free window of enamel, dentine, and cementum (4X4 mm) in the cervical area of the slices was preserved. In control group the slices were subjected to a artificial caries lesion formation. In study groups EcoBio� (President Company), Bio-natural (Dentissimo, Swiss Biodent), and Arthrodont Cassic (Pierre Fabre Oral Care) toothpastes were applied two times a day, for 3 minutes during caries lesion formation. The surface topography has been analyzed using a scanning electron microscope and the quantitative and qualitative chemical composition has been evaluated using an EDX detector. Interprismatic and intraprismatic mineral loss is clearly visible at higher magnification in enamel samples in control group. Some areas of demineralization are still present, and also small areas of extern deposits are visible on enamel, dentine and cementum samples in the groups were tested products were applied. All the tested toothpastes increased calcium and phosphorous ion concentrations in enamel, dentine and cementum. The highest remineralization effect was recorded in enamel by Dentissiomo, followed by Arthrodent and EcoBio toothpastes. In dentine and cementum the highest remineralization effect was registered by Arthrodent, followed by Dentissiomo and EcoBio toothpastes.

[Study regarding coronal fracture probability in posterior amalgam restorations]

Despite minimal invasive orientation in restorative dentistry, in Romania the necessary for extensive restorative treatment in posterior teeth is still high. The silver amalgam still remains a social treatment option for such situation. The purpose of this study was to analyze the efficiency of a new method for analytical determination of the volume of restoration in posterior teeth, knowing that the risk for coronal fracture depends on the size of restoration. The study correlated the results obtained through this method with the real values (mathematically determined) of restorations and the anatomical crowns volumes in order to assess the risk fracture. Amalgam restorations of different types and sizes were placed in 24 extracted premolars and molars. A good global correlation was observed between the true and calculated value (98.321%). The best correlation was observed for MOD restorations (93.042%) while the worst coefficient was obtained for MO restorations (83.378%). The medium restorations presented o correlation of 99.288% and the extensive restorations had an index around 96.957%. This method is based on physics principles and objective measurement resulting in a good correlation with the real dimensions of cavities. Therefore it could be used to assess the risk of crown fracture in teeth with amalgam restorations.

Periodontitis and Cardiovascular Risk

Atherosclerosis is a major component of the cardiovascular diseases and is centered by inflammation but its well-known predictors do not explain some of the atherosclerotic vascular disease events, generating the need to look for independent additional risk factors. Periodontitis, a chronic infection produced by oral bacteria and affecting the supporting structures of the teeth, seems to be linked with atherosclerosis and cardiovascular disease through several mechanisms, like genetic susceptibility, systemic inflammation, infection, and the molecular mimicry, the association being worsened in the presence of diabetes. The epidemiological studies revealed a modest but significant association between periodontal infections and cardiovascular disease, independent of the effect of confounding factors, but the definite effect of periodontitis and its treatment on the incidence of cardiovascular events requires further clarifications.