Tooth Samples Research Articles

Investigation of Chelating Agents for the Removal of Thorium from Human Teeth upon Nuclear Contamination.

Thorium-232 (232Th) is a radioactive heavy metal that is of increasing interest as a source of nuclear energy. However, upon nuclear incidents, the ingestion or inhalation of Th in major quantities can contribute to chemical and radiological health problems, including accumulation in the bone tissue and an increased risk of developing pancreatic, lung, and hematopoietic cancers. The major mineral component of the bone is hydroxyapatite (HAP)─also the major mineral component of the teeth. As such, the teeth are the first site of exposure upon oral ingestion of Th-contaminated materials, and Th can pose a potential risk to teeth development. In essence, in the case of human contamination, it is critical to identify effective chelating agents capable of removing Th. Using a batch study methodology, this present work investigates the uptake and the removal of Th from synthetic HAP and from teeth samples by diethylenetriamine pentaacetate (DTPA), ethylenediaminetetraacetic acid (EDTA), and other promising chelating agents. Th uptake over synthetic HAP exceeds 98% at physiological pH with <1 min of contact time and uptake exceeds 90% across the entire pH range. Regarding teeth, over 1 mg Th uptaken per gram of tooth is observed after 24 h. The overall effectiveness of chelating agents for the removal of Th from is as follows: DTPA > EDTA > NaF/mouthwash/3,4,3-LI(1,2-HOPO); this trend was observed both in synthetic HAP and Th-impregnated teeth samples.

Multidisciplinary evaluation of the remineralization potential of three fluoride-based toothpastes on natural white spot lesions

ObjectivesThis in vitro study aimed assessing the remineralization potential of three commercial fluoride-based toothpastes in permanent teeth with natural white spot lesions (WSLs). A multidisciplinary approach based on Raman microspectroscopy (RMS), Scanning electron microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDS), and Vickers microhardness (VMH) was exploited.MethodsN = 12 human molars with natural WSLs in the proximal-vestibular zone were selected and divided into 4 groups (n = 3) according to the different treatments: HAF (hydroxyapatite with fluoride ions); SMF (sodium monofluorophosphate with arginine); SF (sodium fluoride with enzymes), and CTRL (untreated group). All toothpastes tested contained 1450 ppm of fluoride. Teeth samples were submitted to the following protocol: a 7-day pH cycling treatment, with two daily exposures (2 min each time) to the commercial toothpastes described above. The surface micromorphology (SEM), the chemical/elemental composition (RMS and EDS), and the Vickers microhardness (VMH) were evaluated. Statistical analysis was performed.ResultsA remarkable remineralization of WSLs in SEM images was observed in all treated groups compared to CTRL. In particular, HAF and SF displayed higher values of VMH, phosphates amount (I960), crystallinity (FWHM960), and lower ones of C/P (I1070/I960) with respect to CTRL. Intermediate values were found in SMF, higher than CTRL but lower with respect to HAF and SF. As regards the Ca/P ratio, statistically significant differences (p < 0.05) were found between SF and the other groups.ConclusionsAll the tested dentifrices have shown to remineralize the WSLs. SF and HAF have comparable capability in hardness recovery and crystallinity; however, SF shows the best remineralizing potential according to both micromorphological and chemical analyses.Clinical relevanceThe daily use of toothpastes containing hydroxyapatite partially replaced with fluoride, sodium monofluorophosphate with arginine and sodium fluoride toothpaste associated with enzymes represents a preventive, therapeutic, effective, and non-invasive tool for remineralize WSLs.

DNA identification from dental pulp and cementum

Teeth are one of the body tissues remaining after severe decomposition from which a DNA profile can be obtained to aid in human identification. Currently, the standard approach to isolate DNA from teeth requires pulverizing the entire tooth. This destructive approach compromises any further morphological or anthropological study. We report on two methods of DNA isolation that minimizes destruction of the tooth when accessing the DNA within pulp and cementum. Forty-nine teeth, removed as part of normal dental procedures, were buried for up to 92 days, with a further nine teeth acting as unburied controls. Additionally, four teeth samples collected during a forensic examination were included in this study. The two processes were: using a fine drill to access the pulp from the crown and then using endodontic files to collect the biological material; and using a sterile blade to scrape the cementum. It was found that the samples collected from the cementum had greater DNA quality compared to those samples obtained from the pulp. Microbial activity was found to play a role in the degradation of the nuclear material, reducing DNA yields from pulp. DNA profiling data from 24 loci, including 22 STR markers, indicated that multi-rooted teeth provided better DNA quantity and quality than those with a single root. The DNA quantity obtained from pulp samples of teeth which exhibited cavities was adversely affected, although this DNA loss was not from samples collected from the cementum of teeth in similar condition. Obtaining samples from DNA profiling from the cementum was found to be ideal if the morphological preservation of the tooth is required. Obtaining pathogen DNA is of interest when an occlusal approach to retrieve pulp may serve as a good alternative to prepare DNA without destruction of the tooth structure.

Effect of Hand and Ultrasonic Scaling-Root Planing Methods on Tooth Surface Topography: An In-Vitro Atomic Force Microscopy Study.

Any instrumentation on the tooth surface for plaque or calculus removal will cause some amount of roughness on the tooth surface. Hence, this study was proposed to investigate the effects of hand and ultrasonic scaling and root planing on enamel and cementum, respectively. Forty tooth samples were prepared from extracted maxillary and mandibular first pre-molars and were divided randomly into four groups of 10 samples each. Group l: received ultrasonic scaling on enamel; Group II: received hand scaling on enamel surface; Group III: root planing with an ultrasonic unit on the cementum samples; and Group IV: root planing using hand curettes on cementum surface. The amount of roughness produced on the surface of each sample of all four groups was evaluated using atomic force microscopy (AFM) and statistically analyzed using Chi-square, ANOVA, and Wilcoxon tests. The results suggested that the surface roughness produced on both crown and root after scaling and root planing (SRP) using a hand instrument is lower than that of an ultrasonic unit. The roughness of the crown was found to be lower than that of the root after SRP using both a hand instrument and an ultrasonic unit and was also statistically significant (P= 0.034). In contrast, there is not enough evidence to conclude a significant difference (P=0.13) between root planing using hand instruments and ultrasonic scaler groups. The combined p-value using the Chi-square test (P=0.026) suggests a statistically significant overall difference between crown and root groups. From the present study, the authors concluded that scaling as well as root planing using an ultrasonic unit cause more tooth (enamel and cementum) surface roughness as compared to hand scaling and root planing. While there is no significant difference in the surface roughness of root-cementum produced due to the root planing in both groups, crown-enamel exhibits a significant difference after scaling in both groups. Clinical significance of the study: Rough, uneven tooth surfaces negatively influence the anticipated healing of the periodontium by providing retention areas for microbial dental plaque.

On Roth’s “human fossil” from Baradero, Buenos Aires Province, Argentina: morphological and genetic analysis

The “human fossil” from Baradero, Buenos Aires Province, Argentina, is a collection of skeleton parts first recovered by the paleontologist Santiago Roth and further studied by the anthropologist Rudolf Martin. By the end of the nineteenth century and beginning of the twentieth century it was considered one of the oldest human skeletons from South America's southern cone. Here, we present the results of an interdisciplinary approach to study and contextualize the ancient individual remains. We discuss the context of the finding by first compiling the available evidence associated with the historical information and any previous scientific publications on this individual. Then, we conducted an osteobiographical assessment, by which we evaluated the sex, age, and overall preservation of the skeleton based on morphological features. To obtain a 3D virtual reconstruction of the skull, we performed high resolution CT-scans on selected skull fragments and the mandible. This was followed by the extraction of bone tissue and tooth samples for radiocarbon and genetic analyses, which brought only limited results due to poor preservation and possible contamination. We estimate that the individual from Baradero is a middle-aged adult male. We conclude that the revision of foundational collections with current methodological tools brings new insights and clarifies long held assumptions on the significance of samples that were recovered when archaeology was not yet professionalized.

Anti-microbial efficiency of gaseous ozone's combined use with fluoride and chlorhexidine on time-related oral biofilm: an in situ study on pediatric patients.

Oral biofilm formation is the main reason for both caries progression and soft tissue diseases. Preventing the formation and promotion of biofilm has been known as the first attempt to prevent the development of caries and soft tissue problems in the oral cavity. The present study aimed to assess the effect of ozone and its combined use with chlorhexidine (CHX) and fluoride on the complex biofilm formation of pediatric patients under in situ conditions. Extracted bovine teeth were sterilized and cut into 2 × 3 mm2 sections. The samples were placed in removable maxillary plates and 10 healthy individuals (6 boys, 4 girls; aged 7-14 years) were asked to wear these plates for 6, 24 and 48 hours. Afterwards, the tooth samples were removed, and anti-plaque agents were applied to the time-related plaque formation. Plaque thickness and viable bacterial percentages were detected by confocal laser scanning microscopy. All materials used in the study decreased the plaque formation and the percentage of viable microorganisms compared with the control group (physiological saline). In 6- and 24-hour biofilm evaluations, ozone-CHX was the most effective group in decreasing the plaque thickness (P > 0.05). Ozone-CHX and Ozone-Fluoride groups were found to be better in 48-hour biofilm assessments in caries-free group (P > 0.05). Ozone-CHX group showed a better inhibitory effect on the viability of microorganisms in 6-, 24- and 48-hour biofilm formations (P < 0.05). Although CHX has been known as the gold standard for inhibiting the oral biofilm formation, according to the results of the study, gaseous ozone and its combined use with CHX have shown better results in reducing the biofilm thickness and viable bacterial percentages of in situ formed time-related biofilm formation in pediatric patients. The use of gaseous ozone can be preferred in clinical conditions in pediatric patients instead of the CHX agents.

Ex vivo study of molecular changes of stained teeth following hydrogen peroxide and peroxymonosulfate treatments

White teeth can give confidence and tend to be associated with a healthier lifestyle in modern society. Therefore, tooth-bleaching strategies have been developed, including the use of hydrogen peroxide. Recently, peroxymonosulfate has been introduced as an alternative bleaching method to hydrogen peroxide. Although both chemicals are oxidizing agents, their effects on the molecular composition of the stained teeth are yet unknown. In this study, the molecular profiles of teeth bleached with hydrogen peroxide and peroxymonosulfate were compared using Liquid Chromatography-Tandem Mass Spectrometry. Statistical analyses were used to assess the samples. In addition, reference spectral libraries and in silico tools were used to perform metabolite annotation. Overall, principal component analysis showed a strong separation between control and hydrogen peroxide and peroxymonosulfate samples (p < 0.001). The analysis of molecular changes revealed amino acids and dipeptides in stained teeth samples after hydrogen peroxide and peroxymonosulfate treatments. Noteworthy, the two bleaching methods led to distinct molecular profiles. For example, diterpenoids were more prevalent after peroxymonosulfate treatment, while a greater abundance of alkaloids was detected after hydrogen peroxide treatment. Whereas non-bleached samples (controls) showed mainly lipids. Therefore, this study shows how two different tooth-whitening peroxides could affect the molecular profiles of human teeth.

EPR biodosimetry: challenges and opportunities.

This paper briefly examines electron paramagnetic resonance (EPR) techniques to measure dose from exposure to external radiation, assessing their current status, potential future uses and the challenges impacting their progress. We conclude the uses and potential value of different EPR techniques depend on the number of victims and whether they characterize short- or long-term risks from exposure. For large populations, EPR biodosimetry based on in vivo measurements or using co-located inanimate objects offer the greatest promise for assessing acute, life-threatening risk and the magnitude and extent of such risk. To assess long-term risk, ex vivo EPR methods using concentrated enamel from exfoliated teeth are most impactful. For small groups, ex vivo EPR biodosimetry based on available samples of teeth, nails and/or bones are most useful. The most important challenges are common to all approaches: improve the technique's technical capabilities and advance recognition by planning groups of the relative strengths EPR techniques offer for each population size. The most useful applications are likely to be for triage and medical guidance in large events and for radiation epidemiology to evaluate long-term risks.

In vitro assessment of bonding of the total-etch adhesive to carious dentin in molars treated with and without 38% silver diamine fluoride: a study protocol

Background: The aim will be to evaluate and compare the bonding of the total-etch adhesive to carious dentin in molars treated with and without 38% silver diamine fluoride using the universal testing machine and scanning electron microscope. Methods: 30 extracted teeth samples will be been randomly distributed into 2 groups (n=15). The test group will receive the intervention of 38% SDF whereas the control group will not receive any such intervention. Samples in both groups will be restored with resin composite. Assessment will be done based on the primary outcome, which will be determined by microtensile bond strength whereas the secondary outcome will be determined by fracture modes, i.e., cohesive, adhesive, or mixed fracture. Descriptive statistics will be used for the results of each group. Intergroup comparison will be done on the basis of independent sample t-test to detect the mean difference between the two groups. Independent t-test will be run to analyse the type of failure. In all tests, p-values below 0.05 will be considered statistically significant. Conclusion: The study may provide us with a new restorative technique that will not only be less invasive by preserving the remaining tooth structure but will also prevent the risk of caries progression beneath the restoration. Thus, this will contribute to the longevity of the tooth life by the maintenance of its pulpal health which will contribute to the durability and long-term successful outcome of the direct restoration procedure.

Assessment of Digital Intraoral Periapical Radiograph for the Detection of Apical Root Resorption in Inflammatory Periapical Pathologies: A Radiovisiography Study.

Introduction Resorption often takes the form of external inflammatory root resorption. Apical periodontitis or an apical cyst is the most typical cause of external inflammatory root resorption. Failure of endodontic treatment can occur if severe apical root resorption occurs.This is due to the difficulty of reaching these sites.Apical root resorption is usually discovered during routine radiographs and is usually in its later stages. If the lesion is advanced, extraction is the only viable solution. An accurate diagnosis of incipient root resorption is essential.This research is designed to analyze the effectiveness of digital intraoral periapical radiographs in assessing apical root resorption (ARR) related to periapical pathologies. Material and methods Thiscross-sectional radiographic observational researchwas conductedin a dental college and hospital in central India. Radiovisiography (RVG) images of 190 patients' teeth with inflammatory periapical pathologies were evaluated to determine the presence or absence of resorption in the apical area of the root. After the radiographic assessment of the apical root resorption, the extraction of the affected teeth was done under all aseptic conditions. The periapical tissue was sent for histological analysis and the extracted tooth sample was examined for the presence or absence of apical root resorption. Results In comparison to apical periodontitis, the proportion of severe root resorption patients was significantly higher in abscess and periapical granuloma. Using Pearson's Chi-square test, the difference in patient proportions according to the kind of resorption in the three radiological diagnosis groups was statistically significant with a p-value of 0.0058. Conclusion It was concluded that on radiographic examination, digital intraoral periapical radiographs were found to be accurate in determining periapical apical pathologies and apical root resorption.

Enamel Remineralization Efficacy of Coconut Milk and Lyophilized Coconut Extract in Different Concentrations on Demineralized Enamel Surfaces: An In-Vitro Study.

Aim The current study's objective is to determine the remineralizing efficacy of freeze-dried lyophilized coconut extract and coconut milk made from freshly grated coconut on artificial carious lesions produced by pH cycling. Materials and methods Freshly extracted coconut pulp was split into two parts. The first half was blended to obtain coconut milk, and the second part was freeze-dried and lyophilized. Tooth slabs were prepared from extracted third molar teeth. After being demineralized for 72 hours, the tooth samples were remineralized by submerging them in the appropriate remineralizing solution, which is as follows: Group 1 received 25 mL of the Remineralization solution (the control); Group 2 received 2.5 g of coconut milk and 25 mL of the solution (1:1); and Group 3 received 5 g of coconut milk and 25 mL of the solution (2:1). 2.5 g of freeze-dried, lyophilized coconut extract was given to Group 4 along with 25 mL of remineralization solution (1:1), and 5 g of freeze-dried, lyophilized coconut extract was given to Group 5 along with 25 mL of remineralization solution (2:1). Microhardness and contact angle measurements were made. An Excel spreadsheet was filled up with values from after demineralization, and after remineralization. A statistical analysis was performed using SPSS 26.0 (IBM Corp., Armonk, NY). Using descriptive statistics, the pretreatment mean values for the microhardness and contact angle of the various groups were evaluated. Post-hoc Tukey tests were utilized to compare the analytic results of the various groups. Results Among the various concentrations of freshly extracted coconut milk, the contact angle inconcentrations of 1:1 was 81.22 ± 1.62 deg, and that in concentrations of 2:1 was 88.01 ± 1.85 deg. Between the two concentrations of the lyophilized coconut extract group, the contact angle in 1:1 was 75.05 ± 2.29 deg, and in 2:1 was 71.37 ± 0.85 deg. In the coconut milk group, the value of microhardness was 261 ± 6.4 kg/cm2 at a lower concentration and 322 ±3.9 kg/cm2 at a higher concentration. In the lyophilized coconut group, the lower concentration exhibited a microhardness of 211 ±7.2 kg/cm2, whereas in the higher concentration, it was 324 ±4.04 kg/cm2. Conclusion Of the various concentrations of coconut milk and lyophilized coconut used, coconut milk at a higher concentration exhibits the highest contact angle, and the latter at a higher concentration exhibits the lowest contact angle. In both groups, high concentrations of the material exhibited high microhardness values compared to lower concentrations of the same.

A Comparative Evaluation of Enamel Wear Against Different Surface Finished Ceramics: An In Vitro Study.

An essential factor in the clinical acceptability of all ceramic restorations is the degree of tooth enamel wear. Wear of human enamel has been shown to produce traumatic occlusion, loss of vertical dimension, supra eruption of opposing teeth, periodontal disintegration, and temporomandibular dysfunction. To assess and compare enamel wear against two different ceramics (IPS Empress and Zirconia) and against three different ceramic surface treatments (autoglazed, overglazed, and polished). Zirconia and IPS Empress (Ivoclar Vivadent, Liechtenstein) ceramic samples totaled 30, of which 10 each underwent glaze, overglaze, or polishing with Diaglaze polishing paste. Using a horizontal pin on the disc machine, 60 mounted premolar tooth samples were produced and put through wear tests against ceramic discs. Prior to and following wear, the weight of the tooth samples was measured, and the results were then statistically analyzed using the student t-test, unpaired t-test, and analysis of variance (ANOVA). The qualitative data employed proportions, and the quantitative data used mean and standard deviation to express statistical information. The threshold of significance was set at 5% (α = 0.05). The results for weight loss after 25,000 cycles for ceramic surfaces that had been overglazed were just a little bit greater than those for ceramic surfaces that had been autoglazed and polished. In each of the various subgroups, it was shown that the weight loss values obtained with polished ceramic after 25,000 cycles were significantly lower than those obtained with autoglazed and overglazed ceramic surfaces (P=0.001). When comparing the results produced by the two separate primary groups, IPS Empress and Zirconia, there was no statistically significant difference between the autoglazed, overglazed, and polished groups. While statistically significant difference was seen for each subgroup of IPS and Zirconia (p ≤ 0.01), particularly Zirconia glazed (1.227) with a highly significant p-value of 0.00. The findings contribute to the understanding of the potential clinical implications of different ceramic materials and surface finishes in restorative dentistry, offering valuable insights for practitioners in their treatment decisions. Further research and clinical observations may be needed to corroborate these findings and guide evidence-based practices in dental restorations.

Effect of Dentin and Zirconia Surface Treatments with Laser Irradiation Versus Sandblasting on the Bonding Ability of Zirconia.

Objective: This study aimed to investigate the effects of laser irradiation applied to zirconia and tooth surfaces on shear bond strength (SBS) compared with acid etching and sandblasting. Background: The effect of laser irradiation on the bond strength between zirconia and adhesives is a controversial issue for dentin surface treatments. In addition, the effects of different combinations of surface treatments to increase adhesion on both the zirconia and dentin surfaces remain unclear. Materials and methods: A total of 90 tooth samples were assigned into groups according to various pretreatments: control group was left untreated, acid etching, and Erbium, Chromium:Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser irradiation group (15 Hz, 2 W). In addition, the zirconia specimens were separated into three groups (n = 10) according to the different surface treatments performed: sandblasting (120 μm Al2O3), Er,Cr:YSGG laser (15 Hz, 2 W), and as untreated surface. The zirconia samples were cemented to the dentin surface using dual-cure resin cement and subjected to an SBS test at a speed of 0.5 mm/min under a universal testing machine until fractures occurred in the bonding surface. Results: The highest SBS values were observed in Group tooth acid (TA)-zirconia Er,Cr:YSGG laser (ZL), followed by Group tooth Er,Cr:YSGG laser (TL)-zirconia sandblasting (ZS) and Group TA-zirconia control (ZC). The lowest SBS values were found in Group TA-ZS. Significant intergroup difference was noted between Group TA-ZL, Group tooth control (TC)-ZC, Group TL-ZS, and Group TC-ZC. However, no significant difference was noted between Group TA-ZL, Group TL-ZS, and Group TA-ZC. Conclusions: Acid etching and laser treatments applied to the dentin and zirconia surfaces were found to be effective techniques for improving the zirconia-dentin bond, respectively. Clinical Trial Registration number: 33216249-604.01.02-E.24308.

Comparison of root end sealing ability of three retrograde filling materials in teeth with root apices resected at 900 using dye penetration method under fluorescent microscope

Background: The main factor contributing to surgical endodontic dissatisfaction is an inadequate seal at the apex. The material used for retrograde filling should prevent contaminants from penetrating periradicular tissue. So the objective of this study was to evaluate and compare the ability of Mineral Trioxide Aggregate (MTA), Zirconomer and bioactive bone cement to seal the root end as retrograde filling material with apices resected at 900 angles using dye penetration method under fluorescent microscope. Methods: 36 extracted teeth samples were cut at Cementoenamel junction horizontally. Following the customary protocols of, cleaning, shaping and obturation with gutta percha and AH Plus sealer, resection of samples was done 3mm at the apical end at 90 degree angle along the long axis of the tooth with the help of diamond disc. A depth of 3mm of root end cavity was made with diamond coated ultrasonic surgical tip. The samples were randomly allocated in 3 groups: Group I: MTA ; Group II : Zirconomer; Group III: Bioactive Bone Cement . Coating of nail varnish was done with the roots except at the tip. Each material was compacted in the retrocavity using small pluggers. All the retrofilled samples were kept in acridine orange for 24 hours, following which cleaning &amp; bucco-lingual sectioning (vertical) was carried out. Confocal laser scanning fluorescent microscope was used for checking the dye penetration in these samples thereby evaluating sealing ability. Results: Group III (Bioactive Bone Cement) had the highest root end sealing ability with mean (1.4 ± 0.51) followed by Group I (MTA) (2.3 ± 0.65) and lastly Group II (Zirconomer) (4.1 ± 0.57) as root end filling material with apices resected at 900 angle using dye penetration method under fluorescent microscopy which were statistically significant. Conclusions: Bioactive Bone cement can be recommended as an acceptable retrograde filling material.

Scanning Electron Microscopic Analysis of Deformation of TruNatomy File Systems: An Ex-vivo Study.

Aim The aim of the study was to assess the instrument deformation following the usage of the TruNatomy(Dentsply Sirona, USA) file system in extracted premolars using Scanning Electron Microscopy (SEM). Materials and Methods For the present study, 84 extracted mandibular bicuspids were selected. The teeth were divided into two groups: Group 1, TruNatomy(n=42), and Group 2, Hero Shaper(Micro Mega, France) (n=42).The samples were shaped with 0.03 taper to size 36 with TruNatomy instruments and 0.04 taper to size 30 with Hero Shaper instruments. 5 ml of 5.25% Sodium Hypochlorite (NaOCl) and 2 ml of 17% ethylenediaminetetraacetic acid (EDTA) were used for the final irrigation of root canals. The master apical file was used to instrument seven teeth samples for assessing the safety of the instruments after multiple uses and autoclaving. So, a total of six files per group was used for the analysis of any distortions, cracks or micro-fractures after instrumentation of 42 teeth, at the tip (D0) and 5 mm from the tip (D5) of the rotary file under SEM at 500x magnification. Statistical analysis To determine the significance between the groups, the Mann-Whitney U-testwas applied. Results The mean surface wear of the instruments, at the tip (D0) in Group 1 was 1.2857 and in Group 2 was 1.4762. The mean spiral distortion of the instruments, at the tip (D0) in Group 1 was 1.1905 and in Group 2 was 1.4286. A statistically significant difference (P<0.05) was observed between the groups for surface wear and spiral distortion at the tip of the file (D0). There was no significant difference between groups for surface wear and spiral distortion values of the instruments at 5 mm from the tip (D5) (P>0.05). Conclusion The instrument distortion of the rotary file systems analysed was minimal following the biomechanical preparation of seven mandibular bicuspids without root curvature, using a single file. Therefore, both rotary file systems can be considered safe.

A Wider Scope of Analysis on 38% Silver Diamine Fluoride.

This research was conducted to further support previous studies on the effectiveness of 38% silver diamine fluoride on caries arrest. In addition, the number of applications, time between subsequent applications, type of teeth (primary vs. permanent), final restoration following treatment, and the type of restoration, if any, were assessed. It is a retrospective longitudinal study that was conducted using a chart review technique for which a waiver of informed consent was obtained. The research participants' privacy was ensured and protected. All participants' identities remained anonymous and confidential. Furthermore, consentwas collected from participants' sitters during their appointments as a protocol prior to applying 38% silver diamine fluoride (SDF). The current research was reviewed and approved by the Research Ethics Committee at King Faisal Specialist Hospital and Research Center (KFSH&RC). All investigatorsabided by the rules and regulations of the Government of Saudi Arabia, KFSH&RC, and the Research Advisory Council. A population of pediatric patients with primary and/or mixed dentition at a tertiary care hospital who were treated at the dental office between the period from March 2020 to December 2022 were recruited. A consecutive non-random sampling technique was used. The inclusion criteria include cavitated, asymptomatic, and teeth with no signs or symptoms of pulpal involvement. The sample size estimation was done by considering different percentages of success in arresting dental carries by using 38% SDF, with different levels of precision of 95% confidence intervals and with 0.05 level of significance. A 95% success was assumed in arresting dental carries by using 38% SDF, with a precision of ±5%, and with α=0.05, the required teeth sample size was 101. Anticipating some incomplete information and documentation, the sample size may be dynamic. Nighty-seven teeth both primary and permanent were included in this study. Data were analyzed using IBM SPSS Statistical software version 26.0 (Armonk, NY: IBM Corp.) for Windows. Descriptive statistics (mean standard deviation, frequencies, and percentages) were used to describe the quantitative and categorical outcome variables. Pearson's chi-square test and Fisher's exact test were used to compare the proportion success of 38% SDF in relation to the characteristics of study subjects. The odds ratios were used to quantify the measure of association between the success and other categorical study variables. A binary multiple logistic regression was used to identify the independent variables associated with the success of 38% SDF in arresting dental caries. A p-value of <0.05 and 95% confidence intervals were used to report the statistical significance and precision of results. Our current research concluded that different variables associated with 38% SDF, such as thenumber of applications and the time-lapse between applications, had no significant effect on the successful results of the application. Moreover, receiving a final restoration did not affect the success of the treatment when compared to treating with 38% SDF alone. Additionally, the type of final restoration had no impact on the prognosis. Further research using standardized protocols for study designs, detection criteria, outcomes, and statistical designs is needed to supportfindings and establish treatment guidelines.

Inferring odontocete life history traits in dentine using a multiproxy approach (δ15 N, δ44/42 Ca and trace elements).

Understanding the interactions between marine mammals and their environment is critical for ecological and conservation purposes. Odontocetes offer a continuous record of their life history from birth as recorded in annual increments of their tooth dentine. Because dentine is not remodeled and contains collagen, nitrogen stable isotope compositions (δ15 N) reflect nursing and weaning events, life history traits that would otherwise be impossible to retrieve in such elusive marine animals. Yet, capturing the magnitude and temporal changes in these events is constrained by tooth size and sampling resolution. Moreover, historical and fossil specimens undergo collagen decay, hence the need to develop the measurements of other proxies. Here, we present a multiproxy approach to investigate the use of Ca isotope compositions (δ44/42 Ca) in relation to δ15 N and laser ablation profiles for different trace metal (Ba, Mg, Sr, Zn) concentrations across the dentine of a single individual of the common bottlenose dolphin Tursiops truncatus. To help interpret the dentine data, we provide milk elemental compositions and δ44/42 Ca values for two odontocete individuals. We discuss the observed changes in δ44/42 Ca across the dentine as potential markers of birth, weaning interval, incidental ingestion of seawater, trophic level and physiology. Incidental ingestion of seawater during nursing induces a positive offset in δ44/42 Ca values recorded in the early formed dentine. Life history parameters of individual marine mammals are extremely difficult to retrieve due to limitations in observing specimens in the wild and the methodology presented here offers new ecological and paleoecological perspectives.

Monitoring and investigating the alpha emitter’s concentration in toothpaste and teeth, using CR-39 NTDs

ABSTRACT Toothpaste has importance in environmental and biological studies because of its daily usage by humans and its ability to transport radon gas to the teeth when this sample contains radiation like alpha particles; therefore, the purpose of this study is to determine and measure the concentration of radon concentration (alpha particles) emitters from the toothpaste samples with the impact of radioactivity in the toothpaste on the teeth and transfer this effect to the teeth of the volunteer, by using CR-39 NTDs and natural method (passive method) and PVC tube. The alpha emitter’s concentration in the toothpaste samples varies from 0.3557 to 0.7193 ppm and in teeth samples from 0.0089 ppm to 0.0161 ppm. The results showed that the radon concentration in toothpaste samples was lower than the global permissibility limiting of exposure to radon 200 Bq m−3 and the average annual effective dose in the studied samples was in the range of about (1.837 mSvy−1), which was below range (3–10 mSvy−1) reported by the ICRP (1993). Therefore, there is no evidence of health problems and human teeth in safe. A significant strong positive correlation was found (r = 1, p < 0.000) between the concentrations of alpha emitters in toothpaste and in teeth, depending on the volunteer’s age, the allergic reaction of the body to radiation because the concentrations of alpha emitters increase with an increase in age.

Instant identification of dental white spot using K-means algorithm via laser-induced fluorescence and associated hyperspectral imaging.

Dental caries (DC) is a chronic illness that affects 2 billion individuals worldwide, with 520 million of those suffering from it in their primary teeth. It is apparent that early DC detection and subsequent minimally invasive therapy are crucial clinical requirements. The first reversible clinical indication of demineralization is dental white spot (DWS) lesions. However, diagnosing DWS poses extreme challenges for practitioners. In this investigation, a customized laser-induced fluorescence system with a hyperspectral imaging (HI) camera and a non-ionization laser light supply was created for DWS localization and early DC detection. A UV laser diode source with a wavelength of 395nm was used for light stimulation for the 10 test samples of teeth. The emitted signature of the main tooth components, including dentin, DWS, enamel, and DC, was recorded. An attempt was made to increase the system's sensitivity to the fluorescent signal by applying a logarithmic scale to the spectral signature. Moreover, further discrimination may be achieved by signal strength. We identified that the fluorescent signal's peak intensity at 771nm works best for discriminating DWS from normal areas, or DC. For characterizing dentin, the re-emitted frequency at 500nm has the maximum intensity. Next, we presented our imaging grouping strategy that combines visual enhancement through a moving average, MA, filtering and segmenting an image using K-means clustering (K-mc) (K=8) for instant and precise DWS grouping for the constructed HI images at (500nm and 771nm). Despite the tiny structure and its DWS white appearance, our approach could successfully demarcate the DWS on the tested teeth. Dental examiners might benefit from our simple, non-invasive, non-ionizing optical diagnosis approach to help them make their first assessments and experience accurate and exact delineation of the DWS to obtain immediate and higher rates of early-stage DC detection.

Effect of N-Acetylcysteine on initial Carious Enamel Lesions in primary teeth: an In-vitro study

BackgroundDental caries initiates with non-cavitated enamel lesions as the first stage. The cariogenic potential of N-Acetylcysteine (NAC) may be due to its usage frequency and form. This study aimed to evaluate the impact of exposure time of NAC on initial enamel caries-like lesions in primary teeth by assessing the morphological alteration using a scanning electron microscope (SEM) and mineral content using energy dispersive x-ray spectroscopy (EDX).MethodsForty primary incisor teeth were randomly divided into 4 groups S, S1, S2, and S3 (10 specimens/group). Teeth crowns were cut from their roots and inserted into an acrylic mold with its buccal surface directed upward. Centrally isolated enamel window (2 × 2 mm) on the tooth was done. Ten specimens were selected to evaluate normal enamel while the remaining thirty specimens were immersed in demineralizing solution for 96 h to produce enamel caries-like lesions. PH cycling was performed by immersing each tooth sample in 20 mL of demineralizing solution for 3 h then, preserved for the remaining day hours in 10 ml of artificial saliva interspersed with treatments applications with 10 ml NAC for 10 min twice a day for one- or three-months different treatment modalities. Thermocycling was done for all specimens then they were subjected to SEM and EDX analysis. ANOVA and Bonferroni post hoc tests were utilized in data analysis.ResultsIn teeth treated by NAC for 3 months (group-S3), SEM images showed severe loss of enamel architecture with large NAC deposits detected. A meaningful difference was observed among different groups concerning calcium, phosphorus, fluoride, ca/P ratio, carbon, nitrogen, and oxygen contents (P < 0.05).ConclusionNAC had a detrimental impact on enamel caries-like lesions in human primary teeth.