Aim: To test the hypothesis that antimicrobial agents can be incorporated into bis-acryl resin and that the material will inhibit bacterial growth in vitro. Materials and Methods: 0.5%, 1% and 2% triclosan (5-chloro-2...Aim: To test the hypothesis that antimicrobial agents can be incorporated into bis-acryl resin and that the material will inhibit bacterial growth in vitro. Materials and Methods: 0.5%, 1% and 2% triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) and 0.05% 0.01% and 0.15% cetylpyridinium chloride were incorporated into bis-acryl resins and molded into 1 mm × 10 mm discs. The discs were placed on bacterial culture media inoculated with Aggregatibacter actinomycetemcomitans strain Y4, Porphyromonas gingivalis strain SUNYaB A7A1-28 or Streptococcus gordonii strain 10558, incubated and examined for growth inhibition. Results: Triclosan-containing bisacryl resin discs produced dose-dependent zones of growth inhibition for A. actinomycetemcomitans but not S. gordonii or P. gingivalis. Cetylpyridinium chloride-containing discs produced dose-dependent zones of growth inhibition for Porphyromonas gingivalis and Streptococcus gordonii but not A. actinomycetemcomitans. Conclusion: Triclosan and cetylpyridinium chloride can be incorporated into bis-acryl resin and can inhibit the growth of plaque bacteria in a dose dependent manner. Bis-acryl resin containing antimicrobial agents may inhibit in vivo plaque accumulation and gingival inflammation.展开更多
Sports and energy drinks are consumed by more peoplethan ever. Sports and energy drinks may enhance physical resistance, stimulate metabolism, prevent rehydration and replace electrolytes during high activity efforts....Sports and energy drinks are consumed by more peoplethan ever. Sports and energy drinks may enhance physical resistance, stimulate metabolism, prevent rehydration and replace electrolytes during high activity efforts. However, these drinks often have a low pH and are acidic, which can erode enamel and dentin, and increase dentine hypersensitivity. In addition to the adverse effects of sports and energy drinks on tooth structures, they often have the potential to damage restorative materials. These drinks often contain artificial colors which have potential to discolor resin composite materials and glass ionomers. The acidic nature of these drinks could also lead to a degradation, increase in wear, and roughening of the surface of the restorative materials. Many of the negative consequences of sport and energy drinks can be related to their overconsumption among children and teenagers. Patients should be advised to have a healthy diet, and consume soft and energy drinks in moderation, to avoid any negative dental or health consequences. The overconsumption of sports and energy drinks which are high in sugar and have the lowest pH are most likely to cause avoidable dental problems.展开更多
During smile evaluation and anterior esthetic construction, the anatomic and racial variations should be considered in order to achieve better matching results. The aims of this study were to validate an objective met...During smile evaluation and anterior esthetic construction, the anatomic and racial variations should be considered in order to achieve better matching results. The aims of this study were to validate an objective method for recording spontaneous smile process and to categorize the smile and upper lip curvature of Chinese Han-nationality youth. One hundred and eighty-eight Chinese Han-nationality youths （88 males and 100 females） ranged from 20 to 35 years of age were selected. Spontaneous smiles were elicited by watching comical movies and the dynamics of the spontaneous smile were captured continuously with a digital video camera. All subjects＇ smiles were categorized into three types： commissure, cuspid and gummy smile based on video editing software and final images. Subjects＇ upper lip curvatures were also measured and divided into three groups： upward, straight and downward. Reliability analysis was conducted to obtain intra-rater reliabilities on twice measurements. The Pearson Chi-square test was used to compare differences for each parameters （α=0.05）. In smile classification, 60.6% commissure smile, 33.5% cuspid smile and 5.9% gummy smile were obtained. In upper lip measurement, 26.1% upward, 39.9% straight and 34.0% downward upper lip curvature were determined. The commissure smile group showed statistically significant higher percentage of straight （46.5%） and upward （40.4%） in upper lip curvatures （P〈0.05）, while cuspid smile group （65.1%） and gummy smile group （72.7%） showed statistically significant higher frequency in downward upper lip curvature （P〈0.05）. It is evident that differences in upper lip curvature and smile classification exist based on race, when comparing Chinese subjects with those of Caucasian descent, and gender.展开更多
Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of appl...Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of applying 45S5 bioglass (BG) before, after, and during 35% hydrogen peroxide (HP) bleaching on whitening efficacy, physicochemical properties and microstructures of bovine enamel. Seventy-two bovine enamel blocks were prepared and randomly divided into six groups: distilled deionized water (DDW), BG, HP, BG before HP, BG after HP and BG during HP. Colorimetric and microhardness tests were performed before and after the treatment procedure. Representative specimens from each group were selected for morphology investigation after the final tests. A significant color change was observed in group HP, BG before HP, BG after HP and BG during HP. The microhardness loss was in the following order: group HP>BG before HP, BG after HP>BG during HP>DDW, BG. The most obvious morphological alteration of was observed on enamel surfaces in group HP, and a slight morphological alteration was also detected in group BG before HP and BG after HP. Our findings suggest that the combination use of BG and HP could not impede the tooth whitening efficacy. Using BG during HP brought better protective effect than pre/post-bleaching use of BG, as it could more effectively reduce the mineral loss as well as retain the surface integrity of enamel. BG may serve as a promising biomimetic adjunct for bleaching therapy to prevent/restore the enamel damage induced by bleaching agents.展开更多
The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of met...The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant–abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy(Ti-6Al-4V) and cobalt–chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups(n = 6). In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope(SEM) images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups(Po0.05). Titanium was the highest element to be released regardless of abutment size or connection(Po0.05). SEM images showed pitting corrosion prominent on the outer borders of the implant and abutment platform surfaces. In conclusion, implant–abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant–abutment couples.展开更多
Resveratrol,a natural phenolic compound,has been shown to prevent cardiovascular diseases and cancer and exhibit neuroprotective effects.In this study,we examined the neuroprotective and antioxidant effects of resvera...Resveratrol,a natural phenolic compound,has been shown to prevent cardiovascular diseases and cancer and exhibit neuroprotective effects.In this study,we examined the neuroprotective and antioxidant effects of resveratrol against hydrogen peroxide in embryonic neural stem cells.Hydrogen peroxide treatment alone increased catalase and glutathione peroxidase activities but did not change superoxide dismutase levels compared with hydrogen peroxide + resveratrol treatment.Nitric oxide synthase activity and concomitant nitric oxide levels increased in response to hydrogen peroxide treatment.Conversely,resveratrol treatment decreased nitric oxide synthase activity and nitric oxide levels.Resveratrol also attenuated hydrogen peroxide-induced nuclear or mitochondrial DNA damage.We propose that resveratrol may be a promising agent for protecting embryonic neural stem cells because of its potential to decrease oxidative stress by inducing higher activity of antioxidant enzymes,decreasing nitric oxide production and nitric oxide synthase activity,and alleviating both nuclear and mitochondrial DNA damage.展开更多
Stem cells are unspecialized cells that can self renew indefinitely and differentiate into several somatic cells given the correct environmental cues.In the stem cell niche,stem cell-extracellular matrix(ECM)interacti...Stem cells are unspecialized cells that can self renew indefinitely and differentiate into several somatic cells given the correct environmental cues.In the stem cell niche,stem cell-extracellular matrix(ECM)interactions are crucial for different cellular functions,such as adhesion,proliferation,and differentiation.Recently, in addition to chemical surface modifications,the importance of nanometric scale surface topography and roughness of biomaterials has increasingly becoming recognized as a crucial factor for cell survival and host tissue acceptance in synthetic ECMs.This review describes the influence of nanotopography on stem cell phenotypes.展开更多
White spot infiltration emerged as an alternative of non-invasive treatment to halt progression of the lesion, through the use of low viscosity resins that would permeate the porous enamel and form a physical barrier ...White spot infiltration emerged as an alternative of non-invasive treatment to halt progression of the lesion, through the use of low viscosity resins that would permeate the porous enamel and form a physical barrier that would prevent the acid diffusion produced by micro-organisms. Purpose: To compare penetration levels in artificial white spot lesions, of infiltrant resin ICON™and 2 conventional adhesives systems, XP-Bond™and Single Bond 2™. Methodology: White spot lesions (ICDAS code 2) were caused in 75 premolars or third molars were extracted in good conditions, by immersion in a 0.1 M lactic acid solution (pH 4.5) at 37℃ for 8 weeks. They were divided randomly into 3 groups of 25 samples and applied the following resins, Group A: ICON™, B: XP-Bond™and C: Single Bond 2™. Subsequently, the enamel was removed with hydrochloric acid to expose resin saturated area and the samples were metalized with Au-Pd for SEM observation. The resin tags lengths were measured on microphotographs through software, and the values were analyzed with the statistics ANOVA and Scheffé post-test. Results: There were significant differences (p ™(82.7 μm ± 26.8 μm) compared to adhesive systems XP-Bond™(58.5 μm ± 29.3 μm) and Single Bond 2™(44.8 μm ± 32.5 μm). We found no significant differences between the two adhesive systems (p > 0.05). Conclusion: Under the conditions tested, the penetration of infiltrant ICON was significantly higher than the adhesive systems;however, it removes the surface layer of the enamel.展开更多
The aim of this study was to evaluate the biological efficacy of a unique perpendicular protrusion of type-I collagen(Col-I)from TiO2 nanotubes(NT-EPF surface).We hypothesized that the NT-EPF surface would play bifunc...The aim of this study was to evaluate the biological efficacy of a unique perpendicular protrusion of type-I collagen(Col-I)from TiO2 nanotubes(NT-EPF surface).We hypothesized that the NT-EPF surface would play bifunctional roles in stimulating plateletmediated fibroblast recruitment and anchoring fibroblast-derived Col-I to form a perpendicular collagen assembly,mimicking the connective tissue attachment around natural teeth for the long-term maintenance of dental implants.Ti surface modification was accomplished in two steps.First,TiO2 nanotubes(NT)array was fabricated via anodization.Diameters and depths of NTs were controlled by applied voltage and duration.Subsequently,an electrophoretic fusion(EPF)method was applied to fuse Col-I into nanotube arrays in a perpendicular fashion.Surface wettability was assessed by contact angle measurement.The bioactivity of modified TiO2 surfaces was evaluated in terms of NIH3T3 fibroblast attachment,platelet activation,and collagen extension.Early attachment,aggregation,and activation of platelets as well as release of platelet-related growth factors were demonstrated on NTEPF surfaces.Platelet-mediated NIH3T3 cells migration toward NT-EPF was significantly increased and the attached cells showed a typical fibrous morphology with elongated spindle shape.A direct linkage between pseudopod-like processes of fibroblasts to NTEPF surfaces was observed.Furthermore,the engineered EPF collagen protrusion linked with cell-derived collagen in a perpendicular fashion.Within the limitation of this in vitro study,the TiO2 nanotube with perpendicular Col-I surface(NT-EPF)promoted better cell attachment,induced a strong platelet activation which suggested the ability to create a more robust soft tissue seal.展开更多
Purpose: To evaluate tooth preparation for full veneer cast restorations performed by final year dental students in Sudan. Materials and Methods: 117 stone dies from two different dental institutions were collected an...Purpose: To evaluate tooth preparation for full veneer cast restorations performed by final year dental students in Sudan. Materials and Methods: 117 stone dies from two different dental institutions were collected and evaluated. Polyvinylsilioxane impression material was used to produce two impressive replicas of which one was sectioned in faciolingual plane and the other in mesiodistal plane. Occlusal clearance was measured using a digital caliper. Amount of axial preparation was also measured. Impression silhouettes that were produced using an overhead projector were used to measure convergence angle. Working casts were examined for smoothness and evenness of the preparations, existence or absence of additional features of retention and the finishing line were evaluated for its position and continuity. All obtained data were statistically analyzed by using T-test, ANO-VA, and Pearson Chi square tests. P-values ≤ 0.05 were considered as statistically significant. Results: Average taper of the examined preparations was 39.98?, with 44.1? in the faciolingual, and 35.8? in the mesiodistal dimensions. Preparations for full coverage restorations were over prepared. 38.5% of the total number of preparations were found to have finishing lines in the sub and supra gingival positions. 19.66% were unable to maintain continuity of the finishing line all around the preparation. All preparations were generally smooth with no sharp angles, and 1.7% of the preparations had additional retentive features. Conclusion: Within the limitations of this study, it could be concluded that the convergence angle and finishing line preparations were less than adequate in a sizeable proportion of the preparations examined.展开更多
Objective: To evaluate the effectiveness of herbal medicaments such as ginger, rosemary and honey on remineralization of initial enamel lesion.Methods: Demineralized human enamel specimens were measured for baseline s...Objective: To evaluate the effectiveness of herbal medicaments such as ginger, rosemary and honey on remineralization of initial enamel lesion.Methods: Demineralized human enamel specimens were measured for baseline surface microhardness and fluorescence methods. Ten specimens in each of four groups were used in this in vitro recycling study with the following treatments which applied three times a day: 1) sodium fluoride toothpaste(Ipana, Procter & Gamble, Turkey), 2) gingerhoney(Arifoglu Herbals, Anzer Honey, Turkey), 3) ginger-honey-chocolate(Bind Chocolate, Turkey), 4) rosemary oil(Arifoglu Herbals, Turkey). Treatment regimens of demineralization and remineralization cycle were applied for 21 days. The post-treatment data were obtained by measurements of surface microhardness and fluorescence methods.Data were statistically analyzed by ANOVA test with Tukey's honest significant difference test.Results: Enhanced remineralization was observed with several of the treatment systems including ginger + honey and rosemary. Significant differences between treatments were observed by microhardness and Fluore Cam fluorescence assesment, compared to the positive control group(Na F dentifrice). Significantly, greater remineralization was observed with the honey + ginger treatment regimen. No significant differences between groups were observed using the fluorescence assessment method, quantitative lightinduced fluorescence.Conclusions: Herbals(ginger, honey and rosemary) have enhanced remineralization of initial enamel lesion.展开更多
Epithelial-mesenchymal interactions(EMIs) are critical for tooth development.Molecular mechanisms mediating these interactions in root formation is not well understood.Laser capture microdissection(LCM) and subsequent...Epithelial-mesenchymal interactions(EMIs) are critical for tooth development.Molecular mechanisms mediating these interactions in root formation is not well understood.Laser capture microdissection(LCM) and subsequent microarray analyses enable large scale in situ molecular and cellular studies of root formation but to date have been hindered by technical challenges of gaining intact histological sections of non-decalcified mineralized teeth or jaws with well-preserved RNA.Here,we describe a new method to overcome this obstacle that permits LCM of dental epithelia,adjacent mesenchyme,odontoblasts and cementoblasts from mouse incisors and molars during root development.Using this method,we obtained RNA samples of high quality and successfully performed microarray analyses.Robust differences in gene expression,as well as genes not previously associated with root formation,were identified.Comparison of gene expression data from microarray with real-time reverse transcriptase polymerase chain reaction(RT-PCR) supported our findings.These genes include known markers of dental epithelia,mesenchyme,cementoblasts and odontoblasts,as well as novel genes such as those in the fibulin family.In conclusion,our new approach in tissue preparation enables LCM collection of intact cells with well-preserved RNA allowing subsequent gene expression analyses using microarray and RT-PCR to define key regulators of tooth root development.展开更多
The aim of this study was to describe the intensive care unit (ICU) nurses’ knowledge, attitude, and practice of mouth care for their patients. This is a cross sectional hospital based study. A total of 154 ICU nurse...The aim of this study was to describe the intensive care unit (ICU) nurses’ knowledge, attitude, and practice of mouth care for their patients. This is a cross sectional hospital based study. A total of 154 ICU nurses were randomly selected from seven governmental hospitals in Khartoum state and were invited to take part in this study. 97.4% of ICU nurses had high knowledge of the importance of mouth care for ICU patients and similarly for the priority of mouth care. However, only 20% of nurses were found to apply good practice. 64.5% of the nurses received training in mouth care provision, and (81%) indicated that further training would be beneficial. The oral care practice of ICU nurses ranged between average among 57% and poor among 23%. The study highlighted the need for setting of ICU protocols and adoption of advanced training for ICU nurses.展开更多
The aim of this pilot study was to evaluate the shear bond strength of superficial bovine incisor dentin in different crown regions. Bonding was performed to the incisal, middle and cervical thirds of superficial bovi...The aim of this pilot study was to evaluate the shear bond strength of superficial bovine incisor dentin in different crown regions. Bonding was performed to the incisal, middle and cervical thirds of superficial bovine coronal dentin (n = 20) with a two-step etch-and-rinse adhesive (Optibond Solo Plus) and resin composite (Z100). Shear bond strength was evaluated at 24 h and failure modes of representative specimens wereobserved with FE-SEM. Non-parametric Kruskal-Wallis test with a significance level of 0.05 was used for data analysis. Mean shear bond strength values for the incisal, middle, and cervical thirds were 36.9 (3.1), 42.6 (2.6), and 37.1 (2.1) respectively with no significant differences evidenced between the crown thirds (p = 0.19). Observation of the failure mode of representative specimens demonstrated that specimens with high bond strength values exhibited predominantly mixed-type failures whereas low strength specimens exhibited adhesive failures between the dentin and adhesive. The absence of significant differences in shear bond strength between crown thirds indicate that, regardless of tubule orientation, any crown region can be used when superficial bovine incisor dentin is used for shear bond strength testing.展开更多
The purpose of this study was to use scanning electron microscopy (SEM) evaluation to determine the optimal anodizetion conditions needed to generate niobium oxide coatings on titanium alloy dental implant screws. San...The purpose of this study was to use scanning electron microscopy (SEM) evaluation to determine the optimal anodizetion conditions needed to generate niobium oxide coatings on titanium alloy dental implant screws. Sand-blasted titanium alloy dental implants were anodized in dilute hydrofluoric acid (HF(aq)) solution using a Sorensen DLM 300-2 power supply. The HF concentration and anodization time were varied and the resulting implant surfaces were evaluated using a Jeol JSM-5310LV Scanning Electron Microscope to determine the ideal anodization conditions. While HF is necessary to facilitate oxide growth, increasing concentrations resulted in proportionate increases in coating delamination. In a similar manner, a minimum anodization time of 1 hour was necessary for oxide growth but longer times produced more delamination especially at higher HF(aq) concentrations. SEM imaging showed that implants anodized for 1 hour in a 0.1% HF(aq) aqueous solution had the best results. Anodization can be used to generate niobium oxide coatings on sand-blasted Ti alloy dental implants by balancing the competing factors of oxide growth and coating delamination. It is believed that these oxide coatings have the potential to improve osseointegration relative to untreated dental implants when evaluated in an in vivo study.展开更多
Superficial stains and irregularities of the enamelare generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mine...Superficial stains and irregularities of the enamelare generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a lowrotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations.展开更多
The aim of this study was to investigate the effects of two bleaching systems on micro hardness, surface roughness and color stability of two novel dental composites. Ormocer based restorative Admira and nano-filled c...The aim of this study was to investigate the effects of two bleaching systems on micro hardness, surface roughness and color stability of two novel dental composites. Ormocer based restorative Admira and nano-filled composite Clearfil Majesty Esthetic were bleached with 10% carbamide peroxide(Opalescence PF) or 35% hydrogen peroxide(Beyond Max 5) and subsequently immersed in four different staining solutions(coffee, tea, red wine, and cola). Distilled water was used as a control. Color measurements were performed with a spectrophotometer. Vickers micro hardness and roughness data were analyzed with twoway analysis of variance for repeated measures. The analysis of variance was used to compare the color change values. Duncan's multiple comparison test was applied to compare the results(α = 5%). ΔEab* values over 3.3 were considered clinically unacceptable. Micro hardness and surface roughness values of the tested composites were decreased significantly after bleaching applications. Red wine and tea storage caused perceptible discolorations in the composite resin materials after 30 days of 3-hour immersion. Home or office bleaching applications can affect the surface properties of resin composites and accelerate the staining process.展开更多
Objective: To determine quantitatively the amount of demineralization and the ability of commercially available products and an experimental cream to inhibit or reverse orthodontic related demineralization.Methods: A ...Objective: To determine quantitatively the amount of demineralization and the ability of commercially available products and an experimental cream to inhibit or reverse orthodontic related demineralization.Methods: A total of 20 patients who were 25–35 years old and having orthodontic treatment for 6–8 months were chosen.Caries risk assessments were done for each patient and ones with "moderate risk" were included.Patients with fixed orthodontic appliances were divided into 4 groups(5 patients each) including one control and 3 study groups.All patients used same toothpaste 2 times a day during the 3 weeks study period.Additional to the toothpaste first study group used MI Paste Plus(GC, Tokyo, Japan), second study group used Remin Pro(Voco, Cuxhaven, Germany) and third group used an experimental remineralizing cream per day for 3 weeks.Maxillary central and lateral incisors of each patient were examined by FluoreCam(Daraza Therametric Technologies, USA) device.The examinations were performed at baseline and at the end of 1st, 2nd and 3rd weeks.Results: According to the FluoreCam measurements the control group showed significant amount of demineralization at the end of 3 weeks, moreover the amount of demineralization has gradually increased in time.At the end of the study all 3 study groups showed significant amount of remineralization and the amount of remineralization for all the 3 study groups has gradually increased in time.However the amount of remineralization for 3rd study group was lesser than the 1st and 2nd study groups.The remineralization amounts for the 1st and 2 nd study groups were determined to be identical.Conclusions: This study demonstrated that demineralization is measurable around orthodontic brackets and the demineralization can be completely inhibited and/or reversed by the use of commercially available remineralization products.展开更多
Paresthesia is the name given to a temporary or permanent sensory loss caused by several surgical procedures that affected the peripheral sensory nerve.In dentistry,common iatrogenic procedures that can lead to sensor...Paresthesia is the name given to a temporary or permanent sensory loss caused by several surgical procedures that affected the peripheral sensory nerve.In dentistry,common iatrogenic procedures that can lead to sensory loss include third molar removal,blocking of the inferior alveolar展开更多
With a growing population,changes in consumerism behavior and trends in consumption in Indo-Pacific Asia,our seafood processing and consumption practices produce a large volume of waste products.There are several adva...With a growing population,changes in consumerism behavior and trends in consumption in Indo-Pacific Asia,our seafood processing and consumption practices produce a large volume of waste products.There are several advantages in regulating and sustaining shellfish processing industries.The major advantage of waste management is that it leads to better conservation of natural resources in the long run.Shrimp shell waste contains useful biomaterials,which are still untapped due to inadequate waste disposal and solid waste management.Chitin,the major component of shell waste,can be extracted either chemically or biologically.The chemical extraction approaches,which use acids and alkali,could be an environmental burden.On the other hand,biological methods can be eco-friendly alternatives for shell waste management.In this review,recent trends in management of shellfish waste as sources of chitin,conversion of chitin into chitosan,economic aspects of waste treatment and application of chitosan will be discussed.展开更多
文摘Aim: To test the hypothesis that antimicrobial agents can be incorporated into bis-acryl resin and that the material will inhibit bacterial growth in vitro. Materials and Methods: 0.5%, 1% and 2% triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) and 0.05% 0.01% and 0.15% cetylpyridinium chloride were incorporated into bis-acryl resins and molded into 1 mm × 10 mm discs. The discs were placed on bacterial culture media inoculated with Aggregatibacter actinomycetemcomitans strain Y4, Porphyromonas gingivalis strain SUNYaB A7A1-28 or Streptococcus gordonii strain 10558, incubated and examined for growth inhibition. Results: Triclosan-containing bisacryl resin discs produced dose-dependent zones of growth inhibition for A. actinomycetemcomitans but not S. gordonii or P. gingivalis. Cetylpyridinium chloride-containing discs produced dose-dependent zones of growth inhibition for Porphyromonas gingivalis and Streptococcus gordonii but not A. actinomycetemcomitans. Conclusion: Triclosan and cetylpyridinium chloride can be incorporated into bis-acryl resin and can inhibit the growth of plaque bacteria in a dose dependent manner. Bis-acryl resin containing antimicrobial agents may inhibit in vivo plaque accumulation and gingival inflammation.
文摘Sports and energy drinks are consumed by more peoplethan ever. Sports and energy drinks may enhance physical resistance, stimulate metabolism, prevent rehydration and replace electrolytes during high activity efforts. However, these drinks often have a low pH and are acidic, which can erode enamel and dentin, and increase dentine hypersensitivity. In addition to the adverse effects of sports and energy drinks on tooth structures, they often have the potential to damage restorative materials. These drinks often contain artificial colors which have potential to discolor resin composite materials and glass ionomers. The acidic nature of these drinks could also lead to a degradation, increase in wear, and roughening of the surface of the restorative materials. Many of the negative consequences of sport and energy drinks can be related to their overconsumption among children and teenagers. Patients should be advised to have a healthy diet, and consume soft and energy drinks in moderation, to avoid any negative dental or health consequences. The overconsumption of sports and energy drinks which are high in sugar and have the lowest pH are most likely to cause avoidable dental problems.
文摘During smile evaluation and anterior esthetic construction, the anatomic and racial variations should be considered in order to achieve better matching results. The aims of this study were to validate an objective method for recording spontaneous smile process and to categorize the smile and upper lip curvature of Chinese Han-nationality youth. One hundred and eighty-eight Chinese Han-nationality youths （88 males and 100 females） ranged from 20 to 35 years of age were selected. Spontaneous smiles were elicited by watching comical movies and the dynamics of the spontaneous smile were captured continuously with a digital video camera. All subjects＇ smiles were categorized into three types： commissure, cuspid and gummy smile based on video editing software and final images. Subjects＇ upper lip curvatures were also measured and divided into three groups： upward, straight and downward. Reliability analysis was conducted to obtain intra-rater reliabilities on twice measurements. The Pearson Chi-square test was used to compare differences for each parameters （α=0.05）. In smile classification, 60.6% commissure smile, 33.5% cuspid smile and 5.9% gummy smile were obtained. In upper lip measurement, 26.1% upward, 39.9% straight and 34.0% downward upper lip curvature were determined. The commissure smile group showed statistically significant higher percentage of straight （46.5%） and upward （40.4%） in upper lip curvatures （P〈0.05）, while cuspid smile group （65.1%） and gummy smile group （72.7%） showed statistically significant higher frequency in downward upper lip curvature （P〈0.05）. It is evident that differences in upper lip curvature and smile classification exist based on race, when comparing Chinese subjects with those of Caucasian descent, and gender.
基金supported by the Research Fund from Science and Technology Department of Sichuan Province (No. 2009FZ0065)Key Project of the Science and Technology Department of Sichuan Province (No. 2011SZ0101)+1 种基金Doctoral Fund of Ministry of Education of China (No. 20120181120002)supported by Open Fund of State Key Laboratory of Oral Diseases, Sichuan University
文摘Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of applying 45S5 bioglass (BG) before, after, and during 35% hydrogen peroxide (HP) bleaching on whitening efficacy, physicochemical properties and microstructures of bovine enamel. Seventy-two bovine enamel blocks were prepared and randomly divided into six groups: distilled deionized water (DDW), BG, HP, BG before HP, BG after HP and BG during HP. Colorimetric and microhardness tests were performed before and after the treatment procedure. Representative specimens from each group were selected for morphology investigation after the final tests. A significant color change was observed in group HP, BG before HP, BG after HP and BG during HP. The microhardness loss was in the following order: group HP>BG before HP, BG after HP>BG during HP>DDW, BG. The most obvious morphological alteration of was observed on enamel surfaces in group HP, and a slight morphological alteration was also detected in group BG before HP and BG after HP. Our findings suggest that the combination use of BG and HP could not impede the tooth whitening efficacy. Using BG during HP brought better protective effect than pre/post-bleaching use of BG, as it could more effectively reduce the mineral loss as well as retain the surface integrity of enamel. BG may serve as a promising biomimetic adjunct for bleaching therapy to prevent/restore the enamel damage induced by bleaching agents.
基金funded by a scholarship from King Saud University, Kingdom of Saudi Arabia
文摘The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant–abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy(Ti-6Al-4V) and cobalt–chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups(n = 6). In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope(SEM) images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups(Po0.05). Titanium was the highest element to be released regardless of abutment size or connection(Po0.05). SEM images showed pitting corrosion prominent on the outer borders of the implant and abutment platform surfaces. In conclusion, implant–abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant–abutment couples.
基金funded by the Research Fund of Ege University,Project No. 05/ECZ/020
文摘Resveratrol,a natural phenolic compound,has been shown to prevent cardiovascular diseases and cancer and exhibit neuroprotective effects.In this study,we examined the neuroprotective and antioxidant effects of resveratrol against hydrogen peroxide in embryonic neural stem cells.Hydrogen peroxide treatment alone increased catalase and glutathione peroxidase activities but did not change superoxide dismutase levels compared with hydrogen peroxide + resveratrol treatment.Nitric oxide synthase activity and concomitant nitric oxide levels increased in response to hydrogen peroxide treatment.Conversely,resveratrol treatment decreased nitric oxide synthase activity and nitric oxide levels.Resveratrol also attenuated hydrogen peroxide-induced nuclear or mitochondrial DNA damage.We propose that resveratrol may be a promising agent for protecting embryonic neural stem cells because of its potential to decrease oxidative stress by inducing higher activity of antioxidant enzymes,decreasing nitric oxide production and nitric oxide synthase activity,and alleviating both nuclear and mitochondrial DNA damage.
基金Supported by The National University of Singapore,Grant No.R-224-000-035-133 and NMRC/1151/2008,Singapore
文摘Stem cells are unspecialized cells that can self renew indefinitely and differentiate into several somatic cells given the correct environmental cues.In the stem cell niche,stem cell-extracellular matrix(ECM)interactions are crucial for different cellular functions,such as adhesion,proliferation,and differentiation.Recently, in addition to chemical surface modifications,the importance of nanometric scale surface topography and roughness of biomaterials has increasingly becoming recognized as a crucial factor for cell survival and host tissue acceptance in synthetic ECMs.This review describes the influence of nanotopography on stem cell phenotypes.
文摘White spot infiltration emerged as an alternative of non-invasive treatment to halt progression of the lesion, through the use of low viscosity resins that would permeate the porous enamel and form a physical barrier that would prevent the acid diffusion produced by micro-organisms. Purpose: To compare penetration levels in artificial white spot lesions, of infiltrant resin ICON™and 2 conventional adhesives systems, XP-Bond™and Single Bond 2™. Methodology: White spot lesions (ICDAS code 2) were caused in 75 premolars or third molars were extracted in good conditions, by immersion in a 0.1 M lactic acid solution (pH 4.5) at 37℃ for 8 weeks. They were divided randomly into 3 groups of 25 samples and applied the following resins, Group A: ICON™, B: XP-Bond™and C: Single Bond 2™. Subsequently, the enamel was removed with hydrochloric acid to expose resin saturated area and the samples were metalized with Au-Pd for SEM observation. The resin tags lengths were measured on microphotographs through software, and the values were analyzed with the statistics ANOVA and Scheffé post-test. Results: There were significant differences (p ™(82.7 μm ± 26.8 μm) compared to adhesive systems XP-Bond™(58.5 μm ± 29.3 μm) and Single Bond 2™(44.8 μm ± 32.5 μm). We found no significant differences between the two adhesive systems (p > 0.05). Conclusion: Under the conditions tested, the penetration of infiltrant ICON was significantly higher than the adhesive systems;however, it removes the surface layer of the enamel.
文摘The aim of this study was to evaluate the biological efficacy of a unique perpendicular protrusion of type-I collagen(Col-I)from TiO2 nanotubes(NT-EPF surface).We hypothesized that the NT-EPF surface would play bifunctional roles in stimulating plateletmediated fibroblast recruitment and anchoring fibroblast-derived Col-I to form a perpendicular collagen assembly,mimicking the connective tissue attachment around natural teeth for the long-term maintenance of dental implants.Ti surface modification was accomplished in two steps.First,TiO2 nanotubes(NT)array was fabricated via anodization.Diameters and depths of NTs were controlled by applied voltage and duration.Subsequently,an electrophoretic fusion(EPF)method was applied to fuse Col-I into nanotube arrays in a perpendicular fashion.Surface wettability was assessed by contact angle measurement.The bioactivity of modified TiO2 surfaces was evaluated in terms of NIH3T3 fibroblast attachment,platelet activation,and collagen extension.Early attachment,aggregation,and activation of platelets as well as release of platelet-related growth factors were demonstrated on NTEPF surfaces.Platelet-mediated NIH3T3 cells migration toward NT-EPF was significantly increased and the attached cells showed a typical fibrous morphology with elongated spindle shape.A direct linkage between pseudopod-like processes of fibroblasts to NTEPF surfaces was observed.Furthermore,the engineered EPF collagen protrusion linked with cell-derived collagen in a perpendicular fashion.Within the limitation of this in vitro study,the TiO2 nanotube with perpendicular Col-I surface(NT-EPF)promoted better cell attachment,induced a strong platelet activation which suggested the ability to create a more robust soft tissue seal.
文摘Purpose: To evaluate tooth preparation for full veneer cast restorations performed by final year dental students in Sudan. Materials and Methods: 117 stone dies from two different dental institutions were collected and evaluated. Polyvinylsilioxane impression material was used to produce two impressive replicas of which one was sectioned in faciolingual plane and the other in mesiodistal plane. Occlusal clearance was measured using a digital caliper. Amount of axial preparation was also measured. Impression silhouettes that were produced using an overhead projector were used to measure convergence angle. Working casts were examined for smoothness and evenness of the preparations, existence or absence of additional features of retention and the finishing line were evaluated for its position and continuity. All obtained data were statistically analyzed by using T-test, ANO-VA, and Pearson Chi square tests. P-values ≤ 0.05 were considered as statistically significant. Results: Average taper of the examined preparations was 39.98?, with 44.1? in the faciolingual, and 35.8? in the mesiodistal dimensions. Preparations for full coverage restorations were over prepared. 38.5% of the total number of preparations were found to have finishing lines in the sub and supra gingival positions. 19.66% were unable to maintain continuity of the finishing line all around the preparation. All preparations were generally smooth with no sharp angles, and 1.7% of the preparations had additional retentive features. Conclusion: Within the limitations of this study, it could be concluded that the convergence angle and finishing line preparations were less than adequate in a sizeable proportion of the preparations examined.
文摘Objective: To evaluate the effectiveness of herbal medicaments such as ginger, rosemary and honey on remineralization of initial enamel lesion.Methods: Demineralized human enamel specimens were measured for baseline surface microhardness and fluorescence methods. Ten specimens in each of four groups were used in this in vitro recycling study with the following treatments which applied three times a day: 1) sodium fluoride toothpaste(Ipana, Procter & Gamble, Turkey), 2) gingerhoney(Arifoglu Herbals, Anzer Honey, Turkey), 3) ginger-honey-chocolate(Bind Chocolate, Turkey), 4) rosemary oil(Arifoglu Herbals, Turkey). Treatment regimens of demineralization and remineralization cycle were applied for 21 days. The post-treatment data were obtained by measurements of surface microhardness and fluorescence methods.Data were statistically analyzed by ANOVA test with Tukey's honest significant difference test.Results: Enhanced remineralization was observed with several of the treatment systems including ginger + honey and rosemary. Significant differences between treatments were observed by microhardness and Fluore Cam fluorescence assesment, compared to the positive control group(Na F dentifrice). Significantly, greater remineralization was observed with the honey + ginger treatment regimen. No significant differences between groups were observed using the fluorescence assessment method, quantitative lightinduced fluorescence.Conclusions: Herbals(ginger, honey and rosemary) have enhanced remineralization of initial enamel lesion.
基金supported by NIH grant no.DE15109 to Dr Martha Somermana grant from the State Key Laboratory of Oral Diseases in Chengdu,China to Dr Hai Zhang
文摘Epithelial-mesenchymal interactions(EMIs) are critical for tooth development.Molecular mechanisms mediating these interactions in root formation is not well understood.Laser capture microdissection(LCM) and subsequent microarray analyses enable large scale in situ molecular and cellular studies of root formation but to date have been hindered by technical challenges of gaining intact histological sections of non-decalcified mineralized teeth or jaws with well-preserved RNA.Here,we describe a new method to overcome this obstacle that permits LCM of dental epithelia,adjacent mesenchyme,odontoblasts and cementoblasts from mouse incisors and molars during root development.Using this method,we obtained RNA samples of high quality and successfully performed microarray analyses.Robust differences in gene expression,as well as genes not previously associated with root formation,were identified.Comparison of gene expression data from microarray with real-time reverse transcriptase polymerase chain reaction(RT-PCR) supported our findings.These genes include known markers of dental epithelia,mesenchyme,cementoblasts and odontoblasts,as well as novel genes such as those in the fibulin family.In conclusion,our new approach in tissue preparation enables LCM collection of intact cells with well-preserved RNA allowing subsequent gene expression analyses using microarray and RT-PCR to define key regulators of tooth root development.
文摘The aim of this study was to describe the intensive care unit (ICU) nurses’ knowledge, attitude, and practice of mouth care for their patients. This is a cross sectional hospital based study. A total of 154 ICU nurses were randomly selected from seven governmental hospitals in Khartoum state and were invited to take part in this study. 97.4% of ICU nurses had high knowledge of the importance of mouth care for ICU patients and similarly for the priority of mouth care. However, only 20% of nurses were found to apply good practice. 64.5% of the nurses received training in mouth care provision, and (81%) indicated that further training would be beneficial. The oral care practice of ICU nurses ranged between average among 57% and poor among 23%. The study highlighted the need for setting of ICU protocols and adoption of advanced training for ICU nurses.
文摘The aim of this pilot study was to evaluate the shear bond strength of superficial bovine incisor dentin in different crown regions. Bonding was performed to the incisal, middle and cervical thirds of superficial bovine coronal dentin (n = 20) with a two-step etch-and-rinse adhesive (Optibond Solo Plus) and resin composite (Z100). Shear bond strength was evaluated at 24 h and failure modes of representative specimens wereobserved with FE-SEM. Non-parametric Kruskal-Wallis test with a significance level of 0.05 was used for data analysis. Mean shear bond strength values for the incisal, middle, and cervical thirds were 36.9 (3.1), 42.6 (2.6), and 37.1 (2.1) respectively with no significant differences evidenced between the crown thirds (p = 0.19). Observation of the failure mode of representative specimens demonstrated that specimens with high bond strength values exhibited predominantly mixed-type failures whereas low strength specimens exhibited adhesive failures between the dentin and adhesive. The absence of significant differences in shear bond strength between crown thirds indicate that, regardless of tubule orientation, any crown region can be used when superficial bovine incisor dentin is used for shear bond strength testing.
文摘The purpose of this study was to use scanning electron microscopy (SEM) evaluation to determine the optimal anodizetion conditions needed to generate niobium oxide coatings on titanium alloy dental implant screws. Sand-blasted titanium alloy dental implants were anodized in dilute hydrofluoric acid (HF(aq)) solution using a Sorensen DLM 300-2 power supply. The HF concentration and anodization time were varied and the resulting implant surfaces were evaluated using a Jeol JSM-5310LV Scanning Electron Microscope to determine the ideal anodization conditions. While HF is necessary to facilitate oxide growth, increasing concentrations resulted in proportionate increases in coating delamination. In a similar manner, a minimum anodization time of 1 hour was necessary for oxide growth but longer times produced more delamination especially at higher HF(aq) concentrations. SEM imaging showed that implants anodized for 1 hour in a 0.1% HF(aq) aqueous solution had the best results. Anodization can be used to generate niobium oxide coatings on sand-blasted Ti alloy dental implants by balancing the competing factors of oxide growth and coating delamination. It is believed that these oxide coatings have the potential to improve osseointegration relative to untreated dental implants when evaluated in an in vivo study.
文摘Superficial stains and irregularities of the enamelare generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a lowrotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations.
基金Funded by the Research Fund of Ataturk University(Nos.2009/324,2011/43)
文摘The aim of this study was to investigate the effects of two bleaching systems on micro hardness, surface roughness and color stability of two novel dental composites. Ormocer based restorative Admira and nano-filled composite Clearfil Majesty Esthetic were bleached with 10% carbamide peroxide(Opalescence PF) or 35% hydrogen peroxide(Beyond Max 5) and subsequently immersed in four different staining solutions(coffee, tea, red wine, and cola). Distilled water was used as a control. Color measurements were performed with a spectrophotometer. Vickers micro hardness and roughness data were analyzed with twoway analysis of variance for repeated measures. The analysis of variance was used to compare the color change values. Duncan's multiple comparison test was applied to compare the results(α = 5%). ΔEab* values over 3.3 were considered clinically unacceptable. Micro hardness and surface roughness values of the tested composites were decreased significantly after bleaching applications. Red wine and tea storage caused perceptible discolorations in the composite resin materials after 30 days of 3-hour immersion. Home or office bleaching applications can affect the surface properties of resin composites and accelerate the staining process.
文摘Objective: To determine quantitatively the amount of demineralization and the ability of commercially available products and an experimental cream to inhibit or reverse orthodontic related demineralization.Methods: A total of 20 patients who were 25–35 years old and having orthodontic treatment for 6–8 months were chosen.Caries risk assessments were done for each patient and ones with "moderate risk" were included.Patients with fixed orthodontic appliances were divided into 4 groups(5 patients each) including one control and 3 study groups.All patients used same toothpaste 2 times a day during the 3 weeks study period.Additional to the toothpaste first study group used MI Paste Plus(GC, Tokyo, Japan), second study group used Remin Pro(Voco, Cuxhaven, Germany) and third group used an experimental remineralizing cream per day for 3 weeks.Maxillary central and lateral incisors of each patient were examined by FluoreCam(Daraza Therametric Technologies, USA) device.The examinations were performed at baseline and at the end of 1st, 2nd and 3rd weeks.Results: According to the FluoreCam measurements the control group showed significant amount of demineralization at the end of 3 weeks, moreover the amount of demineralization has gradually increased in time.At the end of the study all 3 study groups showed significant amount of remineralization and the amount of remineralization for all the 3 study groups has gradually increased in time.However the amount of remineralization for 3rd study group was lesser than the 1st and 2nd study groups.The remineralization amounts for the 1st and 2 nd study groups were determined to be identical.Conclusions: This study demonstrated that demineralization is measurable around orthodontic brackets and the demineralization can be completely inhibited and/or reversed by the use of commercially available remineralization products.
文摘Paresthesia is the name given to a temporary or permanent sensory loss caused by several surgical procedures that affected the peripheral sensory nerve.In dentistry,common iatrogenic procedures that can lead to sensory loss include third molar removal,blocking of the inferior alveolar
基金This review paper was supported by Research No.RP170-05/19,MAHSA Research Grant,MAHSA University。
文摘With a growing population,changes in consumerism behavior and trends in consumption in Indo-Pacific Asia,our seafood processing and consumption practices produce a large volume of waste products.There are several advantages in regulating and sustaining shellfish processing industries.The major advantage of waste management is that it leads to better conservation of natural resources in the long run.Shrimp shell waste contains useful biomaterials,which are still untapped due to inadequate waste disposal and solid waste management.Chitin,the major component of shell waste,can be extracted either chemically or biologically.The chemical extraction approaches,which use acids and alkali,could be an environmental burden.On the other hand,biological methods can be eco-friendly alternatives for shell waste management.In this review,recent trends in management of shellfish waste as sources of chitin,conversion of chitin into chitosan,economic aspects of waste treatment and application of chitosan will be discussed.
