Dentin Samples Research Articles

Testing Assumptions for Stable Isotope Analysis of Marine Mammal Dentin Growth Layer Groups.

Stable isotope analysis of growth layer groups (GLGs) in mammal dentin is an increasingly prevalent and noninvasive approach to study animal foraging ecology. However, empirical evidence to support assumed proper methodologies for sampling GLGs is lacking. Here, we examine the effects of intratooth and intertooth variations with respect to targeted GLGs, as well as the effects of common pretreatments (e.g., formic acid and graphite) to enhance GLG visibility, on stable isotope values (δ13C and δ15N) from dentin. We measured the δ13C and δ15N values of killer whale (Orcinus orca) dentin. We used dentin from 37 teeth to compare stable carbon (δ13C) and nitrogen (δ15N) isotope values from multiple locations within a GLG (intratooth variation), from corresponding GLGs among teeth of an individual (intertooth variation), and from treated and untreated teeth. We observed no significant differences in the δ13C or δ15N values when sampling a single GLG from multiple locations (intratooth variation) or when comparing the same GLG across duplicate teeth of individuals (intertooth variation). One tooth in a triplicate set showed a significantly different but likely biologically inconsequential δ13C value. Lastly, formic acid and graphite highlighting to accentuate GLGs did not significantly influence measured stable isotope values. We validate several previous assumptions in this field of study. First, dentin samples for stable isotope analysis can be sampled from different locations across a GLG. Second, researchers can compare stable isotope values from the same GLGs of different teeth collected from the same individual in most cases, as the δ13C and δ15N values did not vary with the sampled tooth. Third, a common protocol of formic acid and graphite treatment to enhance GLG visibility does not bias the δ13C and δ15N values from dentin. We also describe factors to consider and cautions associated with these conclusions.

Strontium isotopes in human mobility research: BASr proxies in an anthropologically modified landscape

Establishing a local 87Sr/86Sr range is a vital requirement for identifying non-locals in bioarchaeological mobility studies using strontium isotopes. In regions heavily influenced by modern human activities, however, the sampling of suitable materials that can be used to decipher the bioavailable 87Sr/86Sr range might be challenging. Here, we collected a wide range of samples representing different reference types of materials from the Nové Mlýny reservoirs area of South Moravia, Czech Republic, and discuss their suitability in human mobility research studies. This included 15 surface water samples, 15 homogenised plant samples, 12 tooth enamel and 1 dentine sample, 1 bone sample from archaeofauna, 6 snail shells and 6 human bones. The measured 87Sr/86Sr ratios revealed the major influence of strontium of non-local origin, carried by the Jihlava river, on the local waterscape. This influence is further enhanced by the changes to the waterscape during the 20th century and carried over to other sample libraries. The presented results demonstrate that special care is needed when selecting reference samples, to allow for a proper understanding of the prevailing conditions in the biologically available strontium (BASr) and to ensure a reliable BASr range estimation.

The influence of tooth shade on near-infrared light transmission through human dentine and enamel: an in-vitro study

This in-vitro study assessed the influence of the shade of human teeth on the transmission of near-infrared light. A total of 40 teeth were used. After cleaning the root surface and removing cementum, the teeth were sectioned into slices 3 mm thick, with each comprising a portion of the crown (enamel-dentine (ED)) and of the root (dentine only). The shade of the crown and the root was measured using a digital spectrophotometer. All samples were irradiated using 660, 808, or 904 nm diode lasers, and a multi-wavelength LED light source (700–1100 nm, Nuralyte®). Using a laser power meter, the percent transmission was calculated. Differences between Vita shade groups A, B, and C were analysed using ANOVA and post-hoc tests. Overall, dentine samples showed approximately 40% greater transmission than samples of enamel and dentine. There were significant influences for shade group and for sample thickness on the transmission of 660 nm light (P < 0.01), but not for other light sources. There was a statistically significant influence of light source on transmission. Across both crown and root samples, the ranking for light transmission from greatest to least was LED (700–1100 nm) > (904 nm = 808 nm) > 660 nm. Within the range from 660 to 1100 nm, the longer wavelengths are transmitted better by both enamel and dentine. The transmission of visible red light (660 nm) was affected by Vita tooth shade, while the transmission of near infrared light (700–1100 nm) was not affected by Vita shade.

Development of a novel laboratory approach for evaluating the adhesion strength of biofilms to human dentine.

Biofilms may show varying adherence strengths to dentine. This study quantified the shear force required for the detachment of multispecies biofilm from the dentine using fluid dynamic gauging (FDG) and computation fluid dynamics (CFD). To date this force has not been quantified. Multispecies biofilms were grown over 3, 7 and 14 days on 2 mm thick dentine sections of human molars (n = 8 per group). The FDG technique with different suction flow rates (100%, 80% and 40%) was used to assess biofilm removal. At maximum suction (100%), the flow rate was 500 mL/min. Digital images of each stained dentine sample were captured (10× magnification) before and after subjecting the samples to the various suction flow rates. The change in colour saturation versus control (△E) value was determined to assess removal of biofilm using digital softwares (Image J© and Colormine©). The imposed shear forces were then estimated using CFD and correlated with the △E values. FDG and CFD analysis showed that complete removal of biofilm by using water as the gauging liquid was not possible across any of the experimental groups. Three-day biofilms required significantly lower shear forces for removal than 7-day or 14-day biofilms. The maximum shear forces were seen in the 14-day biofilm group at all flow rates tested. When assessing for residual biofilm on the dentine, the △E value showed residual biofilms of approximately 40% at all time periods at a 100% flowrate. Complete removal of multispecies biofilm was not possible in any experimental group. This study for the first-time records forces needed to remove polymicrobial biofilms form the surface of a dentine sample. Within the limits of this study, mature biofilms require greater shear forces for removal. This is important when planning protocols for biofilm removal.

Effects of different toothpastes against erosive tooth wear of enamel and dentine in vitro

BackgroundThe increase in the prevalence of erosion lesions worldwide has led researchers to develop effective toothpastes with different ingredients to prevent erosion that can protect the tooth surface against acid attacks. There remains a lack of consensus in the literature regarding which toothpaste formulation exhibits the most effective preventive action against erosive tooth wear, highlighting the necessity for further investigation in this field. This study aimed to evaluate the preventive effect of brushing with toothpastes with different ingredients on enamel and dentine erosion.MethodsThe crowns and roots of ninety recently extracted bovine incisors were seperated and ground flat to obtain enamel and dentine surfaces. The obtained specimens were then divided into six groups: Curaprox Enzycal Zero Flouride (fluoride-free), Colgate Total 12 (1450 ppm NaF), Splat Biocalcium (fluoride-free and Nano-HAP), Colgate ProRelief (1450 ppm NaF and arginine), Sensodyne Repair and Protection (1450 ppm NaF and novamin), Opalescence Whitening (1100 ppm NaF). The specimens were immersed in a demineralizing solution for 2 min and in an artificial saliva for 60 min 4 times a day for 5 days. Brushing was performed with the aid of a charged toothbrush immediately after the first and last erosive attacks. Initial and final surface roughness (at the end of fifth day) were measured using a 3D profilometer. The Wilcoxon test was used to compare initial and final roughness values (p < 0.05).ResultsOpalescence Whitening and Curaprox Enzycal Zero Fluoride significantly increased both enamel and dentine surface roughness compared to baseline, demonstrating rougher surfaces than all other groups except Colgate ProRelief (p < 0.001). Sensodyne Repair and Protection and Colgate Total 12 resulted in the smoothest enamel and dentine surfaces, respectively. The increase in surface roughness was significantly higher for enamel samples compared to dentine samples in the Opalescence Whitening group (p < 0.001).ConclusionsWhitening toothpastes may exacerbate dental erosion by increasing surface roughness. The protective properties of fluoride-free toothpastes vary depending on their active ingredient.

Biomimetic remineralization of eroded dentin by synergistic effect of calcium phosphate and plant-based biomodifying agents: An in vitro study

Context: Dentin, due to its organic content, exhibits a high susceptibility to dental erosion owing to its high permeability to intrinsic acids. A crucial challenge for successful remineralization of demineralized dentin is reestablishing a complete spatial relationship between the mineral and collagen. Aims: This study aimed to evaluate the synergistic effect of casein phosphopeptide amorphous calcium phosphate fluoride (CPP-ACPF) with plant-based dentin biomodifying agents: Grape seed extract (GSE), green tea extract (GTE), and cranberry extract (CE) on biomimetic remineralization of eroded dentin. Settings and Design: Dentin samples were prepared and subjected to surface microhardness (SMH) analysis at baseline followed by erosive challenge with hydrochloric acid (0.01M) and pH cycling with citric acid (0.05M) and artificial saliva. The samples in all the groups except the control were subjected to surface treatments: CPP-ACPF, GSE + CPP-ACPF, GTE + CPP-ACPF, and CE + CPP-ACPF. Subjects and Methods: Samples from all the groups were subjected to Vickers Hardness Tester for Post Treatment SMH analysis. Samples were qualitatively evaluated for changes in ultramorphological characteristics of dentin surface using scanning electron microscopy (SEM) and were quantitatively analyzed for changes in the calcium (Ca)/phosphorous (P) ratio using energy dispersive X-ray analysis (EDAX). Statistical Analysis Used: Data obtained were statistically analyzed using ANOVA, paired samples test, and Tukey HSD test. P value &lt; 0.05 was considered statistically significant. Results: The samples pretreated with GSE showed the highest mean SMH followed by GTE and CE. The difference in % change was significant when GSE was compared to GTE and CE (P = 0.001 and P = 0.000, respectively). SEM pictomicrographs of demineralized dentin samples revealed enlarged and exposed dentinal tubules, and most of these tubules were unobstructed with no obvious sediments. Samples treated with test agents demonstrated amorphous crystal-like deposits occluding the dentinal tubules with higher incidence observed in the groups treated with the combination of the agents. EDAX analysis revealed the highest mean wt% of Ca and P in groups pretreated with GSE followed by GTE and CE. GSE showed the highest mean Ca/P ratio followed by CE and GTE. Conclusions: The findings of this study demonstrated a synergistic effect when CPP-ACPF was used after pretreatment with plant-based dentin biomodifying agents in causing biomimetic remineralization of eroded dentin.

Dentinal tubule occlusion effects of dipotassium oxalate and diode laser combination: a single-blind in vitro study

BackgroundDentin hypersensitivity (DH) affects many patients. Various therapeutic options have been devised to alleviate this condition by achieving dentinal tubules (DT) occlusion. This research aimed to investigate the effects of dipotassium oxalate-containing mouthwash, diode laser and their combination on DT occlusion.MethodsForty dentin samples were obtained from 20 human single-rooted third molars, 40 dentin specimens were obtained, and exposed DT were created in vitro. They were assigned into four groups: Group 1 (n = 10), the control group where no treatment was applied; Group 2 (n = 10), a mouthwash with a 1.4% dipotassium oxalate was applied twice for 60 s during a 5-day period in a shaker at 100 rpm; Group 3 (n = 10), a combination of the same mouthwash and an 810 nm diode laser at an output power of 0.25 W in continuous mode was applied for 60 s without contact at a distance of 3–4 mm; and Group 4 (n = 10), only a diode laser with the same protocol was applied. Occlusion of the DT was observed by scanning electron microscopy.ResultsThe analysis revealed occlusion of the DT in all treatment groups; however, the effects were more pronounced in the combined treatment group (Group 3). Compared with the test groups, the control group had significantly more open DT in 100 µm2 (p < 0.01). The difference between the Group 2 and Group 4 was not significant (p > 0.05).ConclusionDT occlusion was achieved via the use of a mouthwash containing 1.4% dipotassium oxalate and an 810 nm diode laser. However, the combination resulted in the greatest results and therefore may be utilized in individuals with DH.

Simvastatin Efficacy on Endodontic Biofilms: An In Vitro Study.

Mature biofilms were grown on dentin specimens and put in contact with the solutions to determine their antibiofilm activity. To assess residual antimicrobial activity, the dentin samples were immersed for 5 min in the solutions before microbial infection for 3 weeks. The study groups were: (1) 8% SIM, (2) 4% SIM, (3) 4% DC, (4) 2.5% sodium hypochlorite (NaOCl), and (5) 0.9% saline solution (SS). Cell viability was evaluated by means of the adenosine triphosphate (ATP) assay and flow cytometry (FC). The data collected were analyzed with the ANOVA test using Welch's correction followed by the Games-Howell test. The level of statistical significance was p < 0.05, and statistical analysis was performed using SPSS 23.0. All study groups reduced the biofilms significantly with respect to the control. The highest reduction percentage was obtained by 2.5% NaOCl, followed by SIM 8% and 4%, without statistically significant differences. In terms of residual activity, the 4% DC solution obtained a higher percentage of dead cells. Solutions of 4% and 8% SIM, and 4% Diclofenac, show antimicrobial and residual activity against multispecies endodontic biofilms.

Comparative evaluation of the degree of conversion of an 8th-generation bonding agent when applied to normal dentin or caries-affected dentin, pre-treated with MMP inhibitors – An in vitro study

IntroductionThe degree of conversion of dentin bonding agents contributes to the success of final restorations in adhesive dentistry. It is clinically relevant, as it is directly related to the overall bond strength that maintains these restorations in place and prevents marginal deterioration. However, Matrix metalloproteinases (MMPs) present within the dentin substrate have been known to have a deleterious effect on the bond stability, due to their collagenolytic activity. Inhibition of the effects of MMPs has been studied, and the use of a pre-treatment protocol that includes MMP inhibiting agents before bonding procedures has been explored, and has been found to increase bond strengths. However, the effect that MMP inhibitors have on dental adhesives has not yet been explored, particularly when being used in caries-affected-dentin (CAD). This study aims to report the degree of conversion of an 8th-generation dentin bonding agent in sound dentin (SD) vs caries-affected dentin after pre-treatment using MMP inhibitors. Materials & methods60 dentin discs were divided into groups of sound and affected dentin, and pretreated with either Cranberry extract or mulberry extract was applied to half of the discs in each group, followed by the application of an eight-generation bonding agent to the pre-treated discs, which were then light cured. The degree of conversion of the adhesive was calculated using ATR-FTIR spectroscopy. ResultsThe degree of conversion was found to be the highest in the samples of sound dentin which were pre-treated with Mulberry extract. ConclusionPre-treatment of the dentin with MMP inhibitors led to an increase in the degree of conversion in sound dentin but not in CAD.

Assessment of heavy metal contamination in groundwater and its implications for dental and public health

Groundwater contamination with heavy metals is a critical environmental issue, especially in regions heavily reliant on groundwater for drinking purpose. These metals can seep into groundwater from soil and rock weathering or through improper disposal of industrial waste and effluents. Access to safe drinking water is essential for maintaining public health. This study aimed to assess heavy metal contamination in groundwater and its implications for dental and public health. The objective of the study was to measure the concentration of the heavy metals in the dentine of extracted tooth of the study population. The study concurrently measured heavy metal concentrations in groundwater and tooth dentine samples, analyzing demographic profiles, heavy metal correlations, and underlying structures using Principal Component Analysis (PCA). The average level of heavy metals in the groundwater samples varied from 9.763 ± 3.362 μg/L for Cd to 3426.204 ± 875.264 μg/L for Fe. The mean concentrations (μg/g) in teeth dentine showed significant variations, with iron (Fe) ranging from 0.149 ± 0.03 μg/g in water purifiers to 4.62 ± 0.578 μg/g in local water sources. Similar variations were observed for other heavy metals across different water sources. Principal component analysis (PCA) revealed seven principal components, with the first two components explaining 96.1% of the total variance. The findings revealed varied concentrations of heavy metals across all water sources. Statistical analyses underscored the complex relationship between water sources and heavy metal contamination levels, highlighting the need for targeted interventions to improve water quality and mitigate health risks. The study highlights the urgent need for monitoring and mitigation efforts to ensure safe drinking water and mitigate health risks associated with heavy metal contamination.

Cleaning Efficacy of Toothpastes With Varying Abrasiveness-An InVitro Investigation on Bovine Dentin.

To determine how differences in abrasiveness (RDA) influence cleaning capabilities of toothpastes. For this invitro trial, 60 bovine dentin samples were prepared and divided into six groups (G1-G6; n = 10). Groups G1-G5 were arranged in order from low to high toothpaste abrasiveness (G1: RDA: 12, G2: RDA: 29, G3: RDA: 43, G4: RDA: 71, and G5: RDA: 143). Samples in group G6 were used as a negative control and later brushed with pure artificial saliva. In preparation for testing, the dentin samples were stained with a black tea mixture. The respective toothpastes were mixed with artificial saliva in a 1:2 ratio to produce a toothpaste slurry. The samples were brushed for a total of 25 min (with measurement intervals at 2-, 5-, 10-, and 25-min) using a manual toothbrush in an automated brushing machine. The cleaning efficacy of the toothpastes was determined using photographs connected to a planimeter computer program and statistically evaluated. Analysis of the median cleaning efficacy values showed that the toothpastes with a higher abrasiveness achieved a greater cleaning effect at each time point. All toothpastes showed a statistically significant difference (p < 0.05) in their cleaning efficacy (taking into account the median, interquartile range (IQR), minimum and maximum values) after 25 min of brushing. With increasing RDA value, the cleaning efficiency of the toothpastes tested rises. However, a doubling of the RDA value does not necessarily elicit a twofold increase in cleaning effect.

Comparison of a Novel Modality of Erbium-Doped Yttrium Aluminum Garnet Laser-Activated Irrigation and Ultrasonic Irrigation against Mature Enterococcus faecalis Biofilm-An In Vitro Study.

In this in vitro study, we aimed to evaluate and compare the antibacterial efficacy of a novel erbium-doped yttrium aluminum garnet laser modality, shock wave enhanced emission of photoacoustic streaming (SWEEPS), ultrasonically activated irrigation (UAI), and single needle irrigation (SNI) against old bacterial biofilm. A two-week-old Enterococcus faecalis biofilm was cultivated on transversal dentinal discs made from the middle third of the roots of single-rooted, single-canal premolars. Biofilm growth was confirmed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The dentine samples were randomly distributed into three experimental groups and one control group based on the irrigation protocol used: Group 1, SWEEPS; Group 2, UAI; and Group 3, SNI. The root canals were irrigated with a 3% sodium hypochlorite solution. Antibacterial efficacy was evaluated quantitatively through bacterial culture and qualitatively through CLSM and SEM. Both SWEEPS and UAI demonstrated a statistically significant reduction in Enterococcus faecalis colony-forming units (CFUs) (p < 0.001), while SNI did not show a statistically significant reduction (p = 0.553). No significant difference was observed between the efficacy of SWEEPS and UAI (p > 0.05). The SWEEPS and UAI techniques were equally effective in eliminating mature E. faecalis biofilm.

Evaluating the efficacy of cavity disinfection using methylene blue dye with 660-nm diode laser on primary molars: An in vivo study.

The purpose of this study was to evaluate the antimicrobial activity of methylene blue dye with 660-nm diode laser in cavity disinfection and to compare the total bacterial count in dentinal samples preexcavation, postexcavation, and postdisinfection. The study design was experimental in vivo. Fifteen children aged 5-12 years with 15 primary molars requiring atraumatic restorative treatment (ART) were selected. Dentinal samples were collected from the carious tooth with a sterile spoon excavator three times, i.e., before caries excavation (preexcavation), after hand excavation of caries (postexcavation), and after doing laser photodynamic therapy with methylene blue dye and 660-nm diode laser (postdisinfection) and sent for microbiological analysis. The samples were transported in reduced transport fluid. The total bacterial count was carried out by an experienced microbiologist immediately after reporting. A significant number of bacteria was present after hand excavation of caries using ART. The bacterial count significantly reduced postlaser disinfection. The total viable bacterial count was reduced to 87.17% with hand excavation of caries, whereas it was reduced to 98.59% postlaser disinfection using methylene blue dye with 660-nm diode laser. It was seen that ART cannot eliminate all the microorganisms. Methylene blue dye with a 660-nm diode laser was able to reduce the total bacterial count and can be effectively used as an antimicrobial cavity disinfectant.

Comparative evaluation of efficacy of diode laser and bifluorid 10 on dentinal tubule occlusion- A scanning electron microscope (SEM) study

The present study aimed to evaluate the use of Bifluorid 10 and 810-nm diode laser alone on the exposed dentinal tubules by occluding the tubules, which is one of the treatment measures including gels, adhesives, toothpastes and mouthwashes used to treat dentinal hypersensitivity. The study involved 20 periodontally compromised extracted teeth which were sectioned, and dentin samples were prepared. The samples were divided into two groups by using simple randomization technique by tossing a coin; Group A: was treated with Bifluorid 10 alone and Group B: was treated with Laser alone. The treated dentin samples were gold sputtered and were then examined under Scanning electron microscope at a fixed magnification of X5000 and the photomicrographs of the area were obtained. It was seen that the specimens in Group A showed better dentinal tubule occlusion as compared to Group B. Lesser tubule occlusion was seen in Group B. After the evaluation of samples treated with Bifluorid 10 and Laser, it was concluded that Bifluorid 10 had shown better tubule occlusion than Laser.

Impact of cathepsin K-induced proteoglycans degradation on dentin collagen

ObjectivesThis study aimed to investigate the effects of cathepsin K (catK) on proteoglycans (PGs) and the subsequent impacts on dentin collagen degradation. Materials and MethodsDemineralized dentin samples were prepared and divided into the following groups: deionized water (DW), 0.1 U/mL chondroitinase ABC (C-ABC), and 1 μM odanacatib (ODN). Then, they were immersed for 48 h and then incubated in 1 mL of PBS (pH=5.5) at 37 °C for 5 d. Glycosaminoglycan (GAG) were examined to explore the degradation of PGs by catK. To determine the effect of catK-mediated PGs on dentin collagen degradation, hydroxyproline (HYP) assays, assessment of the degree of dentin crosslinking, and scanning electron microscopy (SEM) were assessed. Statistical analysis was conducted using one-way ANOVA followed by Tukey’s tests or Welch's ANOVA followed by Dunnett's tests at a significance level of 0.05. ResultsThe production of GAG was significantly lower in the ODN group than in the DW group (P < 0.05), revealing that PG degradation was reduced in dentin after ODN treatment. Additionally, ODN treatment minimized the gaps in collagen fibers, improved fiber arrangement, and significantly increased the degree of collagen crosslinking, subsequently reducing the total amount of collagen fiber degradation in the dentin (P < 0.05). ConclusionsCatK-mediated degradation of PGs negatively impacted the stability of collagen fibers, promoted gaps, led to a less organized arrangement of dentin collagen fibers, ultimately increasing collagen degradation.

Effects of lactic acid etching on immediate and aged bond strength of resin-dentin bonding interface.

To investigate the effects of lactic acid etching on the immediate and aged bond strength of the resin-dentin bonding interface, the resin-dentin bonding interface was evaluated 24 hours and 6 months later. A total of 42 isolated third molars were randomly divided into 6 experimental groups according to different lactate concentration (35%, 40%, 45%) and acid etching time (30 s, 45 s), with 37% phosphoric acid etching 15 s as a control. In each group, dentin samples were etched under different acidic conditions and bonded with Adper Single Bond 2 (3M ESPE) as directed. The immediate group was immediately stored in deionized water at 37 °C for 24 h, and the aging group was stored in artificial saliva at 37 °C for 6 months. Immediate and aged bond strengths were measured by a micro-tensile tester, and the specimen fracture surface was observed under a microscope. 14 isolated third molars were randomly divided into 7 groups, and each group was etched with acid. Collagen fibers morphology in dentin was examined after gradient dehydration with ethanol by scanning electron microscopy (SEM). Statistically, there was no difference between the resin-dentin immediate bonding strength of 35% lactic acid for 30 s and 37% phosphoric acid for 15 s, but the aged bond strength was greater than that of the phosphoric acid group. According to scanning electron microscope observations, the collagen fiber morphology in 35% and 40% lactate etching dentin 30 s groups was relatively intact compared with other groups. In conclusion, 35% lactic acid etching of dentin 30 s ensures both immediate and aged resin-dentin bond strength.

Comparative evaluation of antibacterial efficacy of nitrofurantoin, chitosan, and calcium hydroxide in combination with propylene glycol as an intracanal medicament against endodontic pathogen - An in vitro study.

The objective is to evaluate and compare the antibacterial efficacy of nitrofurantoin, chitosan, and calcium hydroxide (Ca(OH)2) in combination with propylene glycol (PG) as an intracanal medicament against endodontic pathogens. Fifty-two extracted single-rooted maxillary and mandibular anterior teeth and premolars were selected. The root canals were enlarged using Protaper universal rotary files. Clinical isolates of microorganisms collected from retreatment cases were used. Bacterial isolates obtained from infected root canals were introduced into brain-heart infusion (BHI) broth. Incubation of samples for 14 days was carried out to facilitate the development of mature biofilms. Intracanal medicaments were divided into four groups: Group 1 - Nirofurantoin+20% PG, Group 2 - Chitosan+20% PG, Group 3 - Ca(OH)2 + 20% PG, and Group 4 - 20% PG. The prepared root samples were incubated for 7 days. After collecting dentin samples, they were placed in a phosphate-buffered saline solution. Serial dilutions were then performed, and each dilution was plated on BHI agar. The plates were incubated for 24 h at 37°C. The antibacterial efficacy was assessed by calculating the percentage of remaining colony-forming units. Antibacterial efficacy of chitosan paste was significantly higher followed by nitrofurantoin as compared to other groups when used as an intracanal medicament. In the root-canal biofilm model, the combination of chitosan and PG demonstrated a significant reduction in the viability of endodontic pathogens when employed as intracanal medication for 7 days. This suggests its potential as an effective intracanal medicament for endodontic retreatment.

The damage and remineralization strategies of dental hard tissues following radiotherapy

ObjectivesThis study pursued two main purposes. The first aim was to expound on the microscopic factors of radiation-related caries (RRC). Further, it aimed to compare the remineralization effect of different remineralizing agents on demineralized teeth after radiotherapy.MethodsThe enamel and dentin samples of bovine teeth were irradiated with different doses of radiation. After analysis of scanning electron microscope (SEM), X-Ray diffraction (XRD), and energy dispersive spectrometer (EDS), the samples irradiated with 50 Gy radiation were selected and divided into the demineralization group, the double distilled water (DDW) group, the Sodium fluoride (NaF) group, the Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group, the NaF + CPP-ACP group, and the Titanium tetrafluoride (TiF4) group. After demineralization, remineralizing agents treatment, and remineralization, the samples were evaluated using SEM, atomic force microscope (AFM), EDS, and transverse microradiography (TMR).ResultsA radiation dose of 30 Gy was sufficient to cause damage to the dentinal tubules, but 70 Gy radiation had little effect on the microstructure of enamel. Additionally, the NaF + CPP-ACP group and the TiF4 group significantly promoted deposit formation, decreased surface roughness, and reduced mineral loss and lesion depth of demineralized enamel and dentin samples after radiation.ConclusionsRadiation causes more significant damage to dentin compared to enamel. NaF + CPP-ACP and TiF4 had a promising ability to promote remineralization of irradiated dental hard tissues.Advances in knowledgeThis in vitro study contributes to determining a safer radiation dose range for teeth and identifying the most effective remineralization approach for RRC.

Effect of Vehicles and Irrigation Solutions and Methods on Removal of Double Antibiotic Paste from Root Canals: Insights from High-performance Liquid Chromatography Analysis

IntroductionIn regenerative endodontics, eradicating antibiotic residues from root canals is imperative, given their detrimental effects on human apical papilla stem cells. Previous antibiotic removal studies lacked precision in identifying types and quantities of residual antibiotics. High-performance liquid chromatography (HPLC) enhances sensitivity and specificity, enabling accurate detection and quantification of residual drugs. Using HPLC analysis, this study explored the influence of vehicles and irrigation solutions and methods on double antibiotic paste (DAP) removal from root canals. MethodsTwo DAP formulations, each containing 5 mg/mL ciprofloxacin and metronidazole, were created using distinct vehicles: macrogol and propylene glycol (MP) or hydroxypropyl methylcellulose (HPMC). Subsequently, 5 μL of DAP was applied to 200 simulated immature teeth with open apices (n = 100 per formulation) and cultured for 28 days at 37°C. Samples were then divided into 11 groups (n = 20 per group), and canals were irrigated with 17% ethylenediaminetetraacetic acid or 10% citric acid, employing a positive pressure syringe or passive ultrasonic irrigation. The irrigation solution and dentin sample from each tooth were evaluated via HPLC for ciprofloxacin and metronidazole quantification. ResultsCitric acid exhibited significantly superior efficacy in antibiotic removal from root canals, with no observable effect of irrigation methods on drug removal. The HPMC-based DAP formulation significantly enhanced ciprofloxacin removal compared with MP-based DAP. ConclusionsFor antibiotic paste removal from root canals, citric acid is effective, and HPMC is a preferable vehicle over MP. Overall, HPLC is a valuable method for detecting, removing, and quantifying residual antibiotics in root canals.

In Vitro Evaluation of Remineralization Potential of Five Toothpastes on Soft Drink-Eroded Human Enamel and Dentine.

The purpose of this in vitro study was to evaluate the potential remineralization of enamel and dentine erosion lesions after the application of five different toothpastes. A total of 104 enamel and dentine samples were prepared from maxillary third molars. Each group was divided according to the toothpaste application mode (topical = 56; brushing = 48) and the toothpaste used seven topical groups and six brushing groups (n = 8). The groups included negative control (NC), positive control (PC), Sensodyne Pronamel (SP), Regenerate (R), Regenerate with boosting serum (R+), Colgate Duraphat 5000 (CD), and tooth mousse (TM). The statistical analysis showed significant surface microhardness (SMH) change. All enamel groups showed a significant decrease in SMH compared to NCfor both application modes. However, no significance was recorded between test groups. Similar results were observed between dentine groups and their relevant controls for both application modes, except brushed Rand R+groups, which were insignificant to their NC. For topical groups, TMshowed a significant increase in SMH. While Rand R+showed lower loss than SPand CD. All tested agents offered a degree of remineralization in both enamel and dentine with no significant difference between agents in enamel groups while R, R+, and TMoffered better results in dentine groups. For dentine groups, similar findings were observed with superior tooth surface protection with the application of TM over other agents. Tooth surface remineralization was achieved when agents were either applied topically or brushed over the surface.