In-vitro Thermal Maps to Characterize Human Dental Enamel and Dentin

The crown of a human tooth has an outer layer of highly-mineralized tissue called enamel, beneath which is dentin, a less-mineralized tissue which forms the bulk of the tooth-crown and root. The composition and structure of enamel and dentin are different, resulting in different thermal properties. This gives an opportunity to characterize enamel and dentin from their thermal properties and to visually present the findings as a thermal map. The thermal properties of demineralized enamel and dentin may also be sufficiently different from sound tissue to be seen on a thermal map, underpinning future thermal assessment of caries. The primary aim of this novel study was to produce a thermal map of a sound, human tooth-slice to visually characterize enamel and dentin. The secondary aim was to map a human tooth-slice with demineralized enamel and dentin to consider future diagnostic potential of thermal maps for caries-detection. Two human slices of teeth, one sound and one demineralized from a natural carious lesion, were cooled on ice, then transferred to a hotplate at 30°C where the rewarming-sequence was captured by an infra-red thermal camera. Calculation of thermal diffusivity and thermal conductivity was undertaken, and two methods of data-processing used customized software to produce thermal maps from the thermal characteristic-time-to-relaxation and heat-exchange. The two types of thermal maps characterized enamel and dentin. In addition, sound and demineralized enamel and dentin were distinguishable within both maps. This supports thermal assessment of caries and requires further investigation on a whole tooth

Caracterización de la gingivitis crónica en la población adolescente

Introduction: chronic gingivitis is the inflammatory process that affects the periodontium of protection and alters the normal characteristics of the gingiva, with a high prevalence in adolescents.Objective: to characterize chronic gingivitis in adolescents from 11 to 19 years old in the North Area of Sancti Spiritus province.Methods: an observational, descriptive and cross-sectional study was carried out; the target group comprised 61 adolescents, who attended the Provincial Teaching Dentistry Clinic during the period of September 2019-January 2020. The variables studied were: age, sex, factors of risk, clinical anatomy characteristic, severity of the disease and knowledge about chronic gingivitis. Methods from the theoretical and empirical levels, along with descriptive statistics were used.Results: the age group 17-19 years (45,9 %) predominated, poor oral hygiene (78,7 %) followed by dental caries (47,5 %) and smoking (40,9 %). The level of knowledge was poor in 72,1 % and edematous gingivitis was the one that most affected adolescents, with the highest incidence in the ages from 14 to 16 (36,1%).Conclusions: chronic gingivitis, mainly of the edematous type, was common in male adolescents in ages from 17 to 19. Risk factors such as poor oral hygiene influenced on the onset of this disease. It is necessary to increase the level of knowledge on adolescents to prevent the onset of this condition.Introducción: la gingivitis crónica es el proceso inflamatorio que afecta el periodonto de protección y altera las características normales de la encía, con elevada prevalencia en los adolescentes.Objetivo: caracterizar la gingivitis crónica en los adolescentes de 11 a 19 años del Área Norte de Sancti Spíritus.Métodos: se realizó un estudio observacional, descriptivo y transversal cuyo universo quedó constituido por 61 adolescentes, que acudieron a la Clínica Estomatológica Docente Provincial durante el período de septiembre de 2019 a enero de 2020. Las variables estudiadas fueron: edad, sexo, factores de riesgo, aspecto anatomo clínico, gravedad de la enfermedad y conocimientos sobre gingivitis crónica. Se emplearon métodos del nivel teórico, empírico y de la estadística descriptiva.Resultados: predominó el grupo de edades de 17 a 19 años (45,9 %), la higiene bucal deficiente (78,7 %) seguida de la caries dental (47,5 %) y el tabaquismo (40,9 %). El nivel de conocimientos fue malo en el 72,1 % y la gingivitis edematosa fue la que más afectó a los adolescentes, con mayor incidencia en el grupo de 14 a 16 años (36,1 %).Conclusiones: la gingivitis crónica, principalmente de tipo edematosa fue común en adolescentes masculinos y de edades entre 17 y 19 años. Factores de riesgo como una higiene bucal deficiente condicionan la aparición de la enfermedad. Es necesario incidir en el nivel de conocimientos de los adolescentes para prevenir la aparición de la enfermedad

Emissivity evaluation of human enamel and dentin

Background: Human enamel and dentin temperatures have been assessed with non-contact infrared imaging devices for safety and diagnostic capacity and require an emissivity parameter to enable absolute temperature measurements. Emissivity is a ratio of thermal energy emitted from an object of interest, compared to a perfect emitter at a given temperature and wavelength, being dependent on tissue composition, structure, and surface texture. Evaluating the emissivity of human enamel and dentin is varied in the literature and warrants review. The primary aim of this study was to evaluate the emissivity of the external and internal surface of human enamel and dentin, free from acquired or developmental defects, against a known reference point. The secondary aim was to assess the emissivity value of natural caries in enamel and dentin. Method: Fourteen whole human molar teeth were paired within a thermally stable chamber at 30°C. Two additional teeth (one sound and one with natural occlusal caries–ICDAS caries score 4 and radiographic score RB4) were sliced and prepared as 1-mm-thick slices and placed on a hot plate at 30°C within the chamber. A 3M Scotch Super 33 + Black Vinyl Electrical Tape was used for the known emissivity reference-point of 0.96. All samples were allowed to reach thermal equilibrium, and a FLIR SC305 infrared camera recorded the warming sequence. Emissivity values were calculated using the Tape reference point and thermal camera software. Results: The external enamel surface mean emissivity value was 0.96 (SD 0.01, 95% CI 0.96–0.97), whereas the internal enamel surface value was 0.97 (SD 0.01, 95% CI 0.96–0.98). The internal crown-dentin mean emissivity value was 0.94 (SD 0.02, 95% CI 0.92–0.95), whereas the internal root-dentin value was 0.93 (SD 0.02, 95% CI 0.91–0.94) and the surface root-dentin had a value of 0.84 (SD 0.04, 95% CI 0.77–0.91). The mean emissivity value of the internal enamel surface with caries was 0.82 (SD 0.05, 95% CI 0.38–1.25), and the value of the internal crown-dentin with caries was 0.73 (SD 0.08, 95% CI 0.54–0.92). Conclusion: The emissivity values of sound enamel, both internal and external, were similar and higher than those of all sound dentin types in this study. Sound dentin emissivity values diminished from the crown to the root and root surface. The lowest emissivity values were recorded in caries lesions of both tissues. This methodology can improve emissivity acquisition for comparison of absolute temperatures between studies which evaluate thermal safety concerns during dental procedures and may offer a caries diagnostic aid

Bone Regeneration Using Periodontal Ligament Cells Seeded on Silk Scaffold

Objectives: Bone replacement is one of the critical steps for management of oral bone defects. Many methods have been used to restore such defect. However, biocompatibility and increasing donor site morbidity are still among the main challenges. The current study aims to investigate the potential of using human periodontal ligament cells (hPDLCs) for bone formation, with Bombyx mori fibroin (BMF) silk as a scaffold material. Methods: Human periodontal ligament cells were isolated from human extracted molar teeth that were granted from Leeds Dental School tissue bank. Foam scaffolds were fabricated from BMF in cylindrical shapes. Sterilised scaffolds were subjected to surface modification with 20% Fetal bovine serum (FBS). Calcein fluorescence staining was used to label the cells before being seeded dynamically (4x103 cell/mm3) on BMF scaffolds. For in-vitro experiments, all samples were incubated in osteogenic medium for 21 days. Another group of seeded scaffolds were placed in diffusion chambers and implanted in peritoneal space of CD1 nude mice to evaluate the growth in-vivo. To study the cellular ingrowth, extracellular matrix formation and mineral deposition, all samples were prepared and stained for histological examination. Furthermore, the expression of osteogenic proteins e.g. collagen type I, osteopontin and osteocalcin was detected with immunohistochemical (IHC) stains. Results: After 24 hrs of in-vitro seeding, hPDLCs begin to spread over the scaffold surface as shown by fluorescence microscope images. Cell density increased over a period of 14 days. Histological examination demonstrated that both in-vitro and in-vivo samples showed ingrowth of cells and formation of abundant amounts of extracellular matrix and collagen bundles. Moreover, the presence of black-stained extracellular deposits was detected after staining with Von Kossa stain. Also, osteogenic proteins were detected in both groups. Conclusions: Human periodontal ligament cells that isolated from extracted teeth can proliferate and differentiate into osteoblast-like cells when grown in particular culturing conditions, also, they enhance bone-like tissue formation, both in-vitro and in-vivo

Periodontal regeneration capacity of human periodontal ligament-derived stromal cells

Restoring periodontal defect is still one of the clinical challenges; this is due to the complex structure and diversity of cell types in this joint. The advancement in tissue engineering and cell therapy, make it possible to recruit these approaches to overcome this challenge. This study aims to investigate the capacity of HPDLSCs to differentiation into the main periodontal cell types and enhance the regeneration process. The isolated HPDLSCs were cultured to be characterised for the presence progenitor cell using colony forming unit method. Flow cytometry was used to measure the expression of mesenchymal and hematopoietic cell markers. Furthermore, multilineage cells differentiation was induced. Cells then were seeded on silk scaffold and incubated both in vitro and in vivo in nude mice to examine cellular growth and differentiation. The isolated cells expressed a higher level of MSCs markers in comparison to Hematopoietic markers. Also, these cells showed the ability to proliferate and differentiate into osteogenic, fibrogenic, chondrogenic and adipogenic cues. In Vitro and In Vivo experiments demonstrated the ability of those cells to attach and spread on silk scaffold; In addition to the cellular activities that became evident through the formation of collagen fibres along with the deposition of extracellular minerals. In conclusion, HPDLSCs possess the essential progenitor cells that could differentiate into the primary periodontal cells; Thus, enhancing the periodontal regeneration process

Human periodontal ligament stromal cells: the isolation and characterisation

Restoring periodontal defect is still one of the most challenging clinical needs; this is due to the complex structure and diversity of cell types in this joint. The advancement in tissue engineering and cell therapy made it possible to utilise these approaches to overcome such a challenge. This study aimed to investigate the characteristics of isolated human periodontal ligament cells (HPDLCs), and the multi-linage differentiation capacity of these cells to enhance the regeneration process. Human periodontal ligament cells were isolated from healthy extracted third molar teeth. Colony forming unit-fibroblasts (CFU-f) was used to determine the presence of progenitor cells within the isolated cell population. Further characterisation was conducted by examining the expression levels of mesenchymal stem cells markers (CD29, CD73, STRO-1) as well as the levels of hematopoietic markers (CD34 and CD45), using flow cytometry. Multilineage cells differentiation was induced using adipogenic, chondrogenic, osteogenic and fibrogenic media. Then, the HPDLCs were seeded on 3D Bombyx mori silk fibroin scaffolds in vitro for five weeks and analysed using histology, immunohistochemistry and biochemical assays to confirm proliferation and differentiation processes. Afterwards, the samples were implanted into the peritoneal space of nude mice using diffusion chambers for further seven weeks. All samples were then retrieved from animal models and processed for histology. The data of CFU-f assay demonstrated attachment and proliferation of cultured cells subpopulation onto the vessel’s surface indicating the presence of progenitor stromal cells. Also, HPDLCs expressed higher levels of MSCs markers in comparison to the lower levels of hematopoietic markers. These cells showed the ability to proliferate and differentiate into adipogenic, chondrogenic, osteogenic and fibrogenic cues. Both, in vitro and in vivo experiments demonstrated the ability of those cells to attach and spread on silk scaffolds; as well as performing other cellular activities like formation of collagen fibres, along with the deposition of extracellular minerals. In conclusion, this study showed that HPDLCs contain the essential progenitor stromal cells, which have the capacity to differentiate into the main periodontal cells; this could indicate the role of these cells in enhancing the periodontal regeneration process

The subgingival microbiomes in periodontitis and health of individuals with rheumatoid arthritis and at risk of developing rheumatoid arthritis

Serum anti-citrullinated protein antibodies (ACPAs), present in 70% of people with rheumatoid arthritis (RA), can be detected ≤10years before the onset of clinical disease. RA and periodontitis are epidemiologically associated and we have reported a high incidence of periodontitis in people who are ACPA+ and at risk of RA. Periodontal bacteria may contribute by multiple routes to the generation of RA-autoantibodies. This study aims to characterise the subgingival microbiomes from periodontitis and health in individuals with/without RA and at risk of RA. Forty-five ACPA+ no RA (RA-at-risk; RAR), 31 healthy controls (HC) and 30 ACPA+ RA patients (RA) underwent a periodontal examination. DNA from subgingival plaque from healthy and deep pocket sites were paired-end sequenced using the Illumina HiSeq3000 and data analysed using MG-RAST + DESeq. Metagenomes in RA samples had high proportions of Actinobacteria; RAR microbiomes contained higher proportions of Bacteroidetes than HC. The relative abundance of P. gingivalis was high in periodontitis and RAR; Aggregatibacter actinomycetemcomitans was detected with similar frequency in each group. Other bacteria implicated in periodontitis and/or autoantibody generation (Filifactor alocis, Prevotella spp, Leptotrichia spp.) were detected. Analyses are on-going to elucidate the diversity and functional potential of the subgingival microbiome associated with RA

Prevalence of Periodontal Disease and Periodontopathic Bacteria in Anti–Cyclic Citrullinated Protein Antibody–Positive At-Risk Adults Without Arthritis

Importance: The prevalence of periodontitis is increased in patients with rheumatoid arthritis (RA) and periodontopathic bacteria can citrullinate proteins. Periodontitis may, therefore, be an initiator of RA and a target for prevention. Periodontal disease and periodontal bacteria have not been investigated in at-risk individuals with RA autoimmunity but no arthritis. Objective: To examine periodontal disease and periodontopathic bacteria in anti–cyclic citrullinated protein (anti-CCP) antibody–positive at-risk individuals without arthritis. Design, Setting, and Participants: This cross-sectional study took place at a teaching hospital from April 27, 2015, to May 8, 2017. Forty-eight anti-CCP–positive individuals without arthritis (CCP+ at-risk) were recruited nationally. Twenty-six patients with early RA (ERA) and 32 healthy control individuals were recruited locally. Data were analyzed between June 1, 2017, and December 1, 2017. Interventions: Periodontal assessment and examination of joints using ultrasonography. Main Outcomes and Measures: Prevalence of diseased periodontal sites, clinical periodontitis, and periodontal inflamed surface area in CCP+ at-risk individuals compared with patients with ERA and healthy individuals matched for age and smoking. Paired-end sequencing of DNA from subgingival plaque from diseased and healthy periodontal sites was performed and DNA was profiled and analyzed. Results: A total of 48 CCP+ at-risk individuals (mean [SD] age, 51.9 [11.4] years; 31 [65%] female), 26 patients with ERA (mean [SD] age, 54.4 [16.7] years; 14 [54%] female), and 32 healthy individuals (mean [SD] age, 49.4 [15.3] years; 19 [59%] female) were recruited. Of 48 CCP+ at-risk individuals, 46 had no joint inflammation on ultrasonography. Thirty-five CCP+ at-risk individuals (73%), 12 healthy individuals (38%), and 14 patients with ERA (54%) had clinical periodontitis. The median (interquartile range) percentage of periodontal sites with disease was greater in CCP+ at-risk individuals compared with healthy individuals (3.3% [0%-11.3%] vs 0% [0%-0.7%]) and similar to patients with ERA (1.1% [0%-13.1%]). Median (interquartile range) periodontal inflamed surface area was higher in CCP+ at-risk individuals compared with healthy individuals (221 mm2 [81-504 mm2] vs 40 mm2 [12-205 mm2]). Patients with CCP+ at-risk had increased relative abundance of Porphyromonas gingivalis (but not Aggregatibacter actinomycetemcomitans) at healthy periodontal sites compared with healthy individuals (effect size, 3.00; 95% CI, 1.71-4.29) and patients with ERA (effect size, 2.14; 95% CI, 0.77-3.52). Conclusions and Relevance: This study found increased prevalence of periodontitis and P gingivalis in CCP+ at-risk individuals. This suggests periodontitis and P gingivalis are associated with disease initiation and could be targets for preventive interventions in RA

The prevalence of approximal caries in patients after fixed orthodontic treatment and in untreated subjects : A retrospective, cross-sectional study on bitewing radiographs

OBJECTIVE: The aim of this retrospective, cross-sectional study was to investigate the prevalence of approximal carious lesions in patients after fixed multibracket therapy and in subjects without orthodontics on bitewing radiographs. MATERIAL AND METHODS: Bitewing radiographs of 104 orthodontically treated patients with fixed multibracket appliances were compared to those of 111 untreated subjects. The individuals in both groups were between 15 and 16.25 years of age when radiographs were taken. The test group with orthodontics was recruited from the archive of the Department of Orthodontics at the University of Zürich. The untreated control group was selected randomly from 16 communities in the Canton of Zürich. The approximal surfaces of the permanent premolars and molars of all subjects were assessed by two calibrated investigators. RESULTS: The average number of enamel lesions in the test group after fixed orthodontic treatment was lower than in the control group (0.57 vs. 1.85, p < 0.001). The same was found for dentin lesions (0.06 vs. 0.49, p < 0.001). The distribution of lesions was similar in both groups. CONCLUSION: Fewer approximal carious lesions were detected in the test group after fixed multibracket appliances than in the age-matched control group without orthodontic treatment