Mineral density changes in bovine carious dentin after treatment with bioactive dental cements: a comparative micro-CT study

Objectives

To evaluate the potential of conventional glass ionomer cement (GIC), Biodentine™, MTA, and Portland cement to induce mineral density changes in carious dentin compared to zinc oxide eugenol control cement (ZOE).

Materials and methods

Fifty blocks of bovine root dentin were prepared and a biofilm model using ATCC strains of S.mutans, S.sobrinus, and L.casei was used to promote artificial dentin lesions. After demineralization, the blocks were randomly divided into the five cement groups. Half of the surface of each specimen received the tested material and the other half was covered with wax (control). Samples were stored in phosphate buffered saline solution for 30 days and after that were scanned in a micro-CT with standardized parameters. Dentin mineral density changes were calculated using differences in plot profiles of the exposed and control carious dentin. Friedman’s test, followed by Wilcoxon signed-rank test was used with 5% significance.

Results

Mean ΔZ values for the cements were 48.63 ± 19.09 for the control (ZOE), 63.31 ± 32.59 for Biodentine™, 114.63 ± 72.92 for GIC, 109.56 ± 66.28 for MTA, and 106.88 ± 66.02 for Portland cement. All cements showed a statistically significant increase in ΔZ values compared to the control, but Biodentine™ values were statistically significantly lower compared to GIC and the other calcium silicate cements.

Conclusions

Tested materials present potential to induce mineral density changes in carious bovine dentin. MTA, Portland, and GIC showed higher bioactivity potential than Biodentine™.

Clinical relevance

Based on minimally invasive concept, materials with remineralization potential can be used to preserve diseased but still repairable dental tissue.

     

Response of stem cells from human exfoliated deciduous teeth (SHED) to three bioinductive materials – An in vitro experimental study

IntroductionStem cells have unmatched capacity and potential for regeneration and when used alone or in combination with scaffolds to replace or repair damaged cells, can differentiate into any mature cell.AimTo evaluate the functional differentiation potential of EMD (Enamel Matrix Derivative), MTA (Mineral Trioxide Aggregate) and Biodentine on Stem Cells from Human Exfoliated Deciduous teeth (SHED).ObjectiveTo determine functional differentiation potential (osteogenic/odontogenic) of various biomaterials on SHED.Material and methodSHED derived from 5^th linear passage after sub-culturing were treated with EMD, MTA and Biodentine individually and their effect on cell viability was compared and evaluated by MTT (3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide) assay for 7 days. Alizarin red S staining was used to assess mineralization potential of these materials by the staining calcium deposits for 14 days. The results were analyzed using One-way ANOVA, Post hoc Tukey’s test for multiple comparisons.ResultsIt was observed that EMD imparted the highest cell viability at the end of 7 days (p < 0.001) followed by Biodentine and MTA. Likewise EMD showed highest potential to enhanced mineralization and expression of dentine sialoprotein (p < 0.001) followed by Biodentine and MTA at the end of 14 days (p<0.001).ConclusionIt can be concluded that all the tested materials are bioinductive to SHED. EMD can be used for various vital pulp therapies as that of Biodentine and MTA with predictable as well as enhanced success rate.     

Ion release and physical properties of CPP–ACP modified GIC in acid solutions

A new glass-ionomer cement (GIC) (Fuji VII? EP) includes 3% (w/w) casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) to enhance ion release.ObjectivesTo assess this new GIC compared with a GIC without CPP–ACP (Fuji VII?) with respect to ion release, changes in surface hardness and in mass under a variety of acidic and neutral conditions.MethodsEighty blocks of Fuji VII? (F7) and Fuji VII? EP (F7EP) were subjected to three acidic solutions (lactic and citric acids pH 5.0, hydrochloric acid pH 2.0) and water (pH 6.9) over a three-day period. Ion release, surface hardness and weight measurements were carried out every 24 h.ResultsHigher calcium ion release from F7EP was observed under all acidic conditions. Increased inorganic phosphate ion release was observed for F7EP in hydrochloric and citric acids. Fluoride ion release was similar between F7 and F7EP under all conditions but was significantly higher in acids compared with water. After three days there was no significant difference in surface hardness (p > 0.05) between the two materials under all conditions except hydrochloric acid. Minimal change in mass was observed for F7 and F7EP in water, lactic and hydrochloric acids, however citric acid caused significantly more mass loss compared with water (p < 0.001).ConclusionIncorporation of 3% (w/w) CPP–ACP into F7 enhanced calcium and phosphate ion release, with no significant change in fluoride ion release and no adverse effects on surface hardness or change in mass.Clinical significance statementGICs have the potential to release fluoride ions particularly under acidic conditions associated with dental caries and erosion. A new GIC containing CPP–ACP and fluoride releases not only fluoride ions but also calcium and phosphate ions under acidic conditions which should help to inhibit demineralisation associated with caries and erosion.     

Chemical analysis of in vivo–irradiated dentine of head and neck cancer patients by ATR-FTIR and Raman spectroscopy

Objectives

To evaluate the effect of in vivo radiotherapy on the chemical properties of human dentine by Fourier-transform infrared spectroscopy (FTIR) and Raman analysis.

Materials and methods

Chemical composition was evaluated comparing control and irradiated group (n = 8). Irradiated teeth were obtained from radiotherapy patients subjected to fractionated X-ray radiation of 1.8 Gy daily totaling 72 Gy. The teeth were sectioned according to the type of dentine (crown or root dentine), obtaining 3-mm dentine cervical slices. The analyzed parameters by FTIR and Raman spectroscopies were mineral/matrix ratio (M:M), carbonate/mineral ratio (C:M), amide I/amide III ratio, and amide I/CH₂ ratio. Raman also calculated the phosphate and carbonate crystallinity.

Results

FTIR revealed that M:M had a decrease in both factors (p = 0.008; p = 0.043, respectively) and root dentine showed a lower C:M in the irradiated group (p = 0.003). Raman revealed a higher phosphate crystallinity and a lower carbonate crystallinity in crown dentine of irradiated group (p = 0.021; p = 0.039). For amide I/amide III, the irradiated showed a lower ratio when compared to the control group (FTIR p = 0.002; Raman p = 0.017). For amide I/CH₂, the root dentine showed a higher ratio than the crown dentine in both methods (p < 0.001).

Conclusions

Radiotherapy altered the chemical composition of human dentine. The exchange of phosphate-carbonate ions in the hydroxyapatite and higher concentration of organic components was found after radiotherapy.

Clinical relevance

The increased risk of radiation-related caries in patients undergoing head and neck radiotherapy is due not only to salivary, dietary, and microbiological changes but also to changes in tooth chemical composition.

     

Dentin-cement interfacial interaction: calcium silicates and polyalkenoates

The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine?) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the "mineral infiltration zone", where the alkaline caustic effect of the calcium silicate cement's hydration products degrades the collagenous component of the interfacial dentin. This degradation leads to the formation of a porous structure which facilitates the permeation of high concentrations of Ca(2+), OH(-), and CO(3) (2-) ions, leading to increased mineralization in this region. Comparison of the dentin-restorative interfaces shows that there is a dentin-mineral infiltration with the Biodentine, whereas polyacrylic and tartaric acids and their salts characterize the penetration of the GIC. A new type of interfacial interaction, "the mineral infiltration zone", is suggested for these calcium-silicate-based cements.     

Lasers in dentistry 2. Diagnosis of dental caries with lasers

When enamel, dentine and substances in caries lesions are exposed to (laser) light of a specific colour, fluorescence may be induced. This principle is at the basis of two caries diagnostic methods, DIAGNOdent and Quantitative Laser (Light-induced) Fluorescence (QLF). Only the DIAGNOdent is commercially available. Bacterial porphyrins evoke fluorescence when illuminated with red light and the intensity of the emitted light is related to the size of the caries lesion. Published research indicates that the DIAGNOdent is particularly suitable for detecting small bacteria containing caries lesions, and to monitor such lesions. QLF is based on the fluorescence decrease in demineralised enamel upon exposure to blue-violet (laser) light. The intensity of the emitted light is related to the amount of mineral loss in the caries lesion. Using QLF the mineral loss in caries lesions can be measured quantitatively. Like the DIAGNOdent, QLF is particularly suitable to monitor caries lesions.     

Effects of heat-inactivated Bifidobacterium BB12 on cariogenicity of Streptococcus mutans in vitro

ObjectiveSince some probiotic bacteria are cariogenic themselves, their suitability for caries management is questionable. Inactivated bacteria or their supernatants have been found to exert probiotic effects, whilst having several advantages compared with living bacteria. We hypothesized that viable and heat-inactivated Bifidobacterium animalis BB12 reduces the cariogenicity of Streptococcus mutans (SM) in vitro.DesignWe assessed mono- and mixed species biofilms of SM and viable or heat-inactivated BB12. Biofilms were grown in a continuous-culture-system under cariogenic conditions on smooth proximal enamel or cavitated dentine. For each of eight experimental subsets (4 biofilms × 2 hard-tissue conditions), a total of 32 specimens was used. After 10 days, bacterial numbers of 12 biofilms per group were analysed, and all specimens submitted to transversal microradiography.ResultsMineral loss was higher in cavitated dentine than smooth enamel for all biofilms (p < 0.001, t-test). BB12-monospecies biofilms induced significantly less mineral loss than SM in both enamel (p < 0.05) and dentine (p < 0.001). Viable BB12 did not significantly reduce cariogenicity of SM (p > 0.05), whilst heat-inactivated BB12 decreased cariogenicity of SM in dentinal cavities (p < 0.01). Bacterial numbers were higher on dentine than enamel (p < 0.05), but not significantly influenced by biofilm species (p > 0.05).ConclusionsHeat-inactivated BB12 reduced the cariogenicity of SM in dentinal cavities in vitro. Inactivated probiotics might be suitable for caries control.     

Clinical evaluation of direct pulp capping using a calcium silicate cement—treatment outcomes over an average period of 2.3 years

Objectives

This study aims to assess the treatment outcomes of direct pulp capping with a calcium silicate cement (Biodentine) after caries excavation.

Materials and methods

A total of 245 teeth of 226 patients diagnosed to be clinical healthy or showing spontaneous pain were directly capped. The teeth were examined 0.19 to 7.4 (mean 2.3 ± 2.04) years after treatment. The following data were recorded: age and sex of the patient, type of tooth and restoration (glass ionomer cement [GIC], amalgam, composite resin, ceramic, gold) and symptoms before or after treatment. The evaluation of the treatment was carried out by sensibility and percussion testing and by the patient’s questioning. A positive sensibility test, a negative percussion test, the absence of swelling and discomfort were considered as treatment success. Survival analysis was performed using the Kaplan-Meier, log-rank, Chi-square and Fisher’s exact test, respectively.

Results

After an average period of 2.3 years, 86.0% of the teeth remained vital; the survival rate after 7.4 years was 83.4%. The treatment outcome was significantly worse for cavities restored with GIC compared to all other restorative materials (p < 0.05). All other evaluated factors had no significant influence on the success rate (p > 0.05).

Conclusion

Exposed pulps of asymptomatic vital permanent teeth and teeth with spontaneous pain before treatment can be successfully capped directly using Biodentine. A subsequent restoration with GIC does not appear to be suitable as it significantly reduces the success of the treatment.

Clinical relevance

Direct pulp capping can be done successfully with this type of calcium silicate cement.

     

Do enamel and dentine caries at 5 years of age predict caries development in newly erupted teeth? A prospective longitudinal study

Abstract

Objective: To explore caries development in children from 5 to 12?years of age, and to study whether enamel caries and dentine caries at 5?years of age could predict caries prevalence at 12?years of age, controlled for child characteristics.

Methods: The study included 3282 children examined at 5 and 12?years of age. Data were collected by clinical examination and questionnaire. Enamel and dentine caries were registered at surface level. Data were tested by t-test and analysed by bi- and multivariate logistic regression. The study was ethically approved.

Results: In 5-year-olds, 15% of the children had dentine caries experience and 21% had enamel caries. In 12-year-olds, 32% had dentine caries experience and 47% had enamel caries. Children with dentine caries experience at 5?years of age had at 12?years of age developed more surfaces with enamel caries (mean 2.8, SD 4.2) and dentine caries experience (mean 1.8, SD 2.5) than other children (p?<?.05). Dentine caries experience at 12?years of age was associated with having only enamel caries (OR 1.6, CI 1.2–2.0) and dentine caries experience (OR 3.2, CI 2.6–3.9) at 5?years of age. Family status and parental education were related to caries development.

Conclusion: Children with caries in primary teeth continued to be caries risk children during the mixed dentition period. In addition to dentine caries experience, enamel caries in primary teeth was a predictor for caries development in young permanent teeth and may be used to improve the caries risk assessment.     

Modified tricalcium silicate cement formulations with added zirconium oxide

Objectives

This study aims to investigate the effect of modifying tricalcium silicate (TCS) cements on three key properties by adding ZrO₂.

Materials and methods

TCS powders were prepared by adding ZrO₂ at six different concentrations. The powders were mixed with 1 M CaCl₂ solution at a 3:1 weight ratio. Biodentine (contains 5 wt.% ZrO₂) served as control. To evaluate the potential effect on mechanical properties, the mini-fracture toughness (mini-FT) was measured. Regarding bioactivity, Ca release was assessed using ICP-AES. The component distribution within the cement matrix was evaluated by Feg-SEM/EPMA. Cytotoxicity was assessed using an XTT assay.

Results

Adding ZrO₂ to TCS did not alter the mini-FT (p = 0.52), which remained in range of that of Biodentine (p = 0.31). Ca release from TSC cements was slightly lower than that from Biodentine at 1 day (p > 0.05). After 1 week, Ca release from TCS 30 and TCS 50 increased to a level that was significantly higher than that from Biodentine (p < 0.05). After 1 month, Ca release all decreased (p < 0.05), yet TCS 0 and TCS 50 released comparable amounts of Ca as at 1 day (p > 0.05). EPMA revealed a more even distribution of ZrO₂ within the TCS cements. Particles with an un-reacted core were surrounded by a hydration zone. The 24-, 48-, and 72-h extracts of TCS 50 were the least cytotoxic.

Conclusions

ZrO₂ can be added to TCS without affecting the mini-FT; Ca release was reduced initially, to reach a prolonged release thereafter; adding ZrO₂ made TCS cements more biocompatible.

Clinical relevance

TCS 50 is a promising cement formulation to serve as a biocompatible hydraulic calcium silicate cement.

     

Bioactivity evaluation of calcium silicate‐based endodontic materials used for apexification

This study aims to compare the bioactivity of Biodentine, ProRoot MTA and NeoMTA Plus with regard to their element uptake (Ca, Si and Ca/P) by root canal dentine in a simulated apex (n = 30 each) and evaluate the correlation between the dentine fracture resistance (n = 30 each) and interfacial layer thickness. Specimens immersed in a corrected simulated body solution (c‐SBF) for 1, 30 and 90 days were used. In all test materials, the Ca and Si concentrations in the root dentine were found to be significantly higher, whereas the Ca/P and Si concentrations increased over time (P < 0.05). The dentine fracture resistance showed a difference at only day 30. The dentine fracture resistance of Biodentine and ProRoot MTA was positively correlated with the Si and Ca/P values, and the mean interfacial layer thickness of all specimens. A high biomineralisation capacity of ProRoot MTA and Biodentine, and their positive effects on the dentine fracture resistance during the first 30 days suggest that they may present more advantages than NeoMTA Plus in apexification treatment.     

Push-out bond strength of fiberglass posts cemented with adhesive and self-adhesive resin cements according to the root canal surface

ObjectiveEvaluating the bond strength of fiberglass posts cemented with different resin cements. Materials and Methods: Seventy freshly extracted roots of healthy human canines were endodontically treated and prepared to receive fiberglass posts. The roots were randomly divided into seven groups: (G1) RelyX ARC, (G2) Enforce, (G3) BisCem, (G4) Duo-Link, (G5) Cement Post, (G6) Variolink II, and (G7) RelyX U200. After post cementation, the specimens were sectioned perpendicularly to the root axis using a high-speed diamond disc, totaling 340 specimens. The strength values obtained in the push-out test were submitted to two-factor ANOVA and Tukey test (p = 0.05). Results: The root thirds (p = 0.001) and the type of cement (p = 0.001) influenced the bond strength values. The relation between these two factors was also significant (p = 0.011). Conclusions: The bond strength of self-adhesive resin cements was significantly higher as compared to other cements. Besides the cervical third in roots cemented with conventional cements types presented the highest bond strength values (p < 0.05).     

Mineral loss on adjacent enamel glass ionomer cements restorations after cariogenic and erosive challenges

Objectives

the purpose of this study was to determine the mineral loss on surrounding enamel restored with glass ionomer cements (GIC) after erosive and cariogenic challenges.

Methods

Bovine enamel specimens were randomly assigned into six groups according to the restorative material: G1 – composite resin; G2 – high viscous GIC; G3 – resin-modified glass ionomer with nanoparticles; G4 – encapsulated resin-modified GIC; G5 – encapsulated high viscous GIC; G6 – resin-modified GIC. After restorative procedures, half of specimens in each group were submitted to caries challenge using a pH cycling model for 5 days, and the other half were submitted to erosive challenge in citric acid for 10 min. Before and after the challenges, surface Knoop microhardness assessments were performed and mineral changes were calculated for adjacent enamel at different distances from restorative margin.

Results

Data were compared for significant differences using two-way ANOVA and Student–Newman–Keuls tests (p < 0.05). Erosive challenge significantly reduced enamel surface hardness, but no significant difference was observed irrespectively restorative materials (p > 0.05). The cariogenic challenge promoted a higher surface hardness loss for the resin-modified GIC (G4) and only for the High viscous GIC (G2) an increase in surface hardness was observed. For enamel analyses, significant differences were observed with respect to the different materials (p < 0.001) and distances (p = 0.023). Specimens restored with the composite resin presented higher mineral loss and specimens restored with the conventional high viscous GIC and the encapsulated resin-modified GIC presented the lowest values for mineral loss.

Conclusion

The GICs exerts protective effect only for cariogenic challenge.     

Randomized clinical trial on effectiveness of silver diamine fluoride and glass ionomer in arresting dentine caries in preschool children

ObjectiveTo compare the effectiveness of annual topical application of silver diamine fluoride (SDF) solution, semi-annual topical application of SDF solution, and annual application of a flowable high fluoride-releasing glass ionomer in arresting active dentine caries in primary teeth.MethodsA total of 212 children, aged 3–4 years, were randomly allocated to one of three groups for treatment of carious dentine cavities in their primary teeth: Gp1-annual application of SDF, Gp2-semi-annual application of SDF, and Gp3-annual application of glass ionomer. Follow-up examinations were carried out every six months to assess whether the treated caries lesions had become arrested.ResultsAfter 24 months, 181 (85%) children remained in the study. The caries arrest rates were 79%, 91% and 82% for Gp1, Gp2 and Gp3, respectively (p = 0.007). In the logistic regression model using GEE to adjust for clustering effect, higher caries arrest rates were found in lesions treated in Gp2 (OR = 2.98, p = 0.007), those in anterior teeth (OR = 5.55, p < 0.001), and those in buccal/lingual smooth surfaces (OR = 15.6, p = 0.004).ConclusionAnnual application of either SDF solution or high fluoride-releasing glass ionomer can arrest active dentine caries. Increasing the frequency of application to every 6 months can increase the caries arrest rate of SDF application.Clinical significanceArrest of active dentine caries in primary teeth by topical application of SDF solution can be enhanced by increasing the frequency of application from annually to every 6 months, whereas annual paint-on of a flowable glass ionomer can also arrest active dentine caries and may provide a more aesthetic outcome.     

A modified glass ionomer cement to mediate dentine repair

ObjectivesGlass ionomer cements (GIC) can be used to protect dentine following caries removal. However, GIC have little biological activity on biological repair processes, which means that neo-dentine formation remains reliant on limited endogenous regenerative processes. Wnt/β-catenin signalling is known to play a central role in stimulating tertiary dentine formation following tooth damage and can be stimulated by a range of glycogen synthase kinase (GSK3) antagonists, including lithium ions.MethodsHere, we created lithium-containing bioactive glass (BG) by substituting lithium for sodium ions in 45S5 BG. We then replaced between 10 and 40% of the powder phase of a commercial GIC with the lithium-substituted BG to create a range of formulations of ‘LithGlassGIC’. In vitro physical properties of the resulting glasses were characterised and their ability to stimulate reactionary dentine formation in mouse molars in vivo was tested.ResultsLithium release from LithGlassGIC increased with increasing lithium content in the cement. In common with unmodified commercial GIC, all formations of LithGlassGIC showed in vitro toxicity when measured using an indirect cell culture assay based on ISO10993:5, precluding direct pulp contact. However, in a murine non-exposed pulp model of tooth damage, LithGlassGIC quickly released lithium ions, which could be transiently detected in the saliva and blood. LithGlassGIC also enhanced the formation of tertiary dentine, resulting in a thickening of the dentine at the damage site that restored lost dentine volume. Dentine regeneration was likely mediated by upregulation of Wnt/β-catenin activity, as LithGlassGIC placed in TCF/Lef:H2B-GFP reporter mice showed enhanced GFP activity.SignificanceWe conclude that LithGlassGIC acts as a biological restorative material that promotes tertiary dentine formation and restores tooth structure.     

Which dentine analogue material can replace human dentine for crown fatigue test?

ObjectiveTo seek dentine analogue materials in combined experimental, analytical, and numerical approaches on the mechanical properties and fatigue behaviours that could replace human dentine in a crown fatigue laboratory test.MethodsA woven glass fibre-filled epoxy (NEMA grade G10; G10) and a glass fibre-reinforced polyamide-nylon (30% glass fibre reinforced polyamide-nylon 6,6; RPN) were investigated and compared with human dentine (HD). Flexural strength and elastic modulus (n = 10) were tested on beam-shaped specimens via three-point bending, while indentation hardness (n = 3) was tested after fracture. Abutment substrates of G10, RPN and HD were prepared and resin-bonded with monolithic lithium disilicate crowns (n = 10), then subjected to wet cyclic loading in a step-stress manner (500 N initial load, 100 N step size, 100,000 cycles per step, 20 Hz frequency). Data were statistically analysed using Kruskal-Wallis one-way ANOVA followed by post-hoc comparisons (α = 0.05). Survival probability estimation was performed by Mantel-Cox Log-Rank test with 95% confidence intervals. The fatigue failure load (FFL) and the number of cycles until failure (NCF) were evaluated with Weibull statistics. Finite Element Models of the fatigue test were established for stress distribution analysis and lifetime prediction. Fractographic observations were qualitatively analysed.ResultsThe flexural strength of HD (164.27 ± 14.24 MPa), G10 (116.48 ± 5.93 MPa), and RPN (86.73 ± 3.56 MPa) were significantly different (p < 0.001), while no significant difference was observed in their flexural moduli (p = 0.377) and the indentation hardness between HD and RPN (p = 0.749). The wet cyclic fatigue test revealed comparable mean FFL and NCF of G10 and RPN to HD (p = 0.237 and 0.294, respectively) and similar survival probabilities for the three groups (p = 0.055). However, RPN promotes higher stability and lower deviation of fatigue test results than G10 in Weibull analysis and FEA.SignificanceEven though dentine analogue materials might exhibit similar elastic properties and fatigue performance to human dentine, different reliabilities of fatigue on crown-dentine analogues were shown. RPN seems to be a better substrate that could provide higher reliability and predictability of laboratory study results.     

Caries intensity and Streptococcus mutans in the saliva of patients with Turner syndrome

AimThe aim of this study was to evaluate the caries intensity and Streptococcus mutans (SM) counts in patients with Turner syndrome.Materials and methodsNineteen patients aged 20–40 years were clinically and cytogenetically diagnosed with Turner syndrome (45, X). The karyotype was determined by chromosome analysis of peripheral blood lymphocytes. The control group comprised 47 healthy women aged 21–40 years. Both groups included non-smokers with no specific diet, such as a vegetarian or vegan diet, who were generally healthy with good oral hygiene and periodontal condition. Patients treated with antibiotics or steroid preparations in the past 6 months or with diseases or conditions that might affect the oral mucosal environment, such as disorders of salivary secretion and diabetes, were excluded from the study. Decayed, missing, and filled teeth (DMFT) scores and SM counts in saliva were determined.ResultsNo colony growth of SM was noticed in 53% of patients with Turner syndrome and 4.2% of controls (p < 0.001). Colony counts of SM ≥ 10⁵ in saliva were observed in none of the patients with Turner syndrome but in 66% of controls (p < 0.001). The mean DMFT score was 1.63 ± 2.52 in patients with Turner syndrome and 14.49 ± 6.88 in controls. Statistically significant differences between the two groups were observed (p < 0.05).ConclusionPatients with genetic disorders may have different severities of caries and SM counts in saliva compared to those without genetic disorders. Further studies on saliva properties and genes located on the X chromosome could contribute to determining the effect of the X chromosome on the pathological processes in the oral cavity.     

Influence of composition on setting kinetics of new injectable and/or fast setting tricalcium silicate cements

ObjectivesNew commercial tricalcium silicate based cements were elaborated to improve handling properties and setting time. The goals of the present work were: (i) to determine the composition of the new injectable and/or fast setting calcium silicate based cements, and (ii) to investigate the impact of the differences in composition on their setting kinetics.MethodsThe materials considered were Angelus MTA™, Biodentine™, MM-MTA™, MTA-Caps™, and ProRoot MTA™ as control.Elemental composition of materials was studied by Inductively Coupled Plasma-Atomic Emission Spectroscopy and X-ray Energy Dispersive analysis, whereas phases in presence were analyzed by Micro-Raman spectroscopy and X-ray Diffraction analysis and cement surface by Scanning Electron Microscope. Setting kinetics was evaluated using rheometry.ResultsElemental analysis revealed, for all cements, the presence of three major components: calcium, silicon and oxygen. Chlorine was detected in MM-MTA, MTA-Caps and Biodentine. Different radio-opacifiers were identified: bismuth oxide in ProRoot MTA, Angelus MTA and MM-MTA, zirconium oxide in Biodentine and calcium tungstate (CaWO₄) in MTA-Caps. All cements were composed of di- and tri-calcium silicate, except Biodentine for which only the latter was detected. Major differences in setting kinetics were observed: a modulus of 8 × 10⁸ Pa is reached after 12 min for Biodentine, 150 min for MM-MTA, 230 min for Angelus MTA and 320 min for ProRoot MTA. The maximum modulus reached by MTA-Caps was 7 × 10⁸ Pa after 150 min.SignificanceEven if these cements possess some common compounds, major differences in their composition were observed between them, which directly influence their setting kinetics.     

Push-out bond strength and failure mode of single adjustable and customized glass fiber posts

PurposeTo evaluate the push-out bond strength (PBS) and failure mode of single adjustable (SAP) and customized (CP) posts cemented to root canal dentin using conventional (RelyX Ultimate) or self-adhesive (RelyX U200) dual-cure resin cements.MethodsHerein, 40 bovine mandibular incisors were divided into four groups (n = 10): SAP cemented with RelyX Ultimate (SAP-UT), SAP cemented with RelyX U200 (SAP-U2), CP cemented with RelyX Ultimate (CP-UT), and CP cemented with RelyX U200 (CP-U2). PBS and failure modes were analyzed. Three-way repeated measures ANOVA test followed by Tukey’s test and Fisher–Freeman–Halton exact test were used for data analysis (α = 5%).ResultsThe PBS values for SAP (p < .05) were higher than those for CP and were not influenced by the root third and resin cement (p > .05). When conventional resin cement was used, the SAP showed significant differences compared to CP (p < .05). When cemented with RelyX Ultimate, a higher prevalence of mixed and adhesive failures for SAP and CP, respectively, was observed (p < .05). For the self-adhesive resin cement, the failures were mostly adhesive (p < .05).ConclusionSAP showed better performance than CP. The root third and resin cements did not influence the PBS. The most prevalent failures were adhesive and mixed.     

Biological response to lyophilized demineralized dentin matrix implanted in the subcutaneous tissues of rats

AimLyophilized demineralized dentin matrix (LDDM) consists of a type 1 collagen complex matrix containing growth factors and no mineral crystals. Although the efficacy of LDDM for bone grafting is well known, there is limited evidence on the biological response to human lyophilized DDM. Therefore, the aim of this study was to evaluate the biological response of subcutaneous tissues in rats to powdered LDDM, mineral trioxide aggregate (MTA), and Biodentine implanted using polyethylene tubes.MethodsForty Wistar rats were divided into four groups (n = 10 each) depending on the experimental time intervals and were placed in polyethylene tubes containing LDDM, MTA, biodentine, and one empty control. After 3, 7, 15, and 30 observation days, the animals were sacrificed and quantitative and qualitative analysis of the subcutaneous tissue samples was carried out. The intensity of the inflammatory response was scored from 0 (no response) to 3 (severe response), and the data were statistically analyzed using ANOVA and Bonferroni tests (p < 0.05).ResultsAll groups exhibited moderate inflammation after 3 and 7 days of observation, with presence of inflammatory infiltrate predominantly consisting of macrophages and angioblastic proliferation being observed. After 15 observation days, the control group exhibited mild inflammation and a predominance of fibroblasts, and this differed significantly from the remaining cement groups that exhibited moderate inflammation. After 30 days of observation, all groups exhibited a mild inflammatory response, predominance of fibroblasts, and a greater amount of collagen fibers.ConclusionWithin the limitations of this study, it can be concluded that LDDM exhibited an acceptable biological response similar to MTA and Biodentine in the subcutaneous tissues of rats.