Differential Regulation of Mas-Related G Protein-Coupled Receptor X2-Mediated Mast Cell Degranulation by Antimicrobial Host Defense Peptides and Porphyromonas gingivalis Lipopolysaccharide.

Porphyromonas gingivalis is a keystone pathogen that contributes to periodontal pathogenesis by disrupting host-microbe homeostasis and promoting dysbiosis. The virulence of P. gingivalis likely reflects an alteration in the lipid A composition of its lipopolysaccharide (LPS) from the penta-acylated (PgLPS1690) to the tetra-acylated (PgLPS1435/1449) form. Mast cells play an important role in periodontitis, but the mechanisms of their activation and regulation remain unknown. The expression of epithelium- and neutrophil-derived host defense peptides (HDPs) (LL-37 and human ß-defensin-3), which activate mast cells via Mas-related G protein-coupled receptor X2 (MRGPRX2), is increased in periodontitis. We found that MRGPRX2-expressing mast cells are present in normal gingiva and that their numbers are elevated in patients with chronic periodontitis. Furthermore, HDPs stimulated degranulation in a human mast cell line (LAD2) and in RBL-2H3 cells stably expressing MRGPRX2 (RBL-MRGPRX2). PgLPS1690 caused substantial inhibition of HDP-induced mast cell degranulation, but PgLPS1435/1449 had no effect. A fluorescently labeled HDP (FAM-LL-37) bound to RBL-MRGPRX2 cells, and PgLPS1690 inhibited this binding, but PgLPS1435/1449 had no effect. These findings suggest that low-level inflammation induced by HDP/MRGPRX2-mediated mast cell degranulation contributes to gingival homeostasis but that sustained inflammation due to elevated levels of both HDPs and MRGPRX2-expressing mast cells promotes periodontal disease. Furthermore, differential regulation of HDP-induced mast cell degranulation by PgLPS1690 and PgLPS1435/1449 may contribute to the modulation of disease progression.

The significance of electron microscopic examination of gingiva in cases of Hunter syndrome and hereditary gingival fibromatosis.

INTRODUCTION: Electron microscopy has been for decades a basic morphological method still used in diagnostic protocols of some pathological conditions affecting the ultrastructure of cells and extracellular matrix. The aim of this study was an ultrastructural description of gingiva of patients with Hunter syndrome and hereditary gingival fibromatosis. PATIENTS AND METHODS: Gingival biopsies were obtained during surgical periodontal treatment from a 9-year-old boy with Hunter disease (with enzyme replacement therapy with recombinant human idursulphase) and a 15-year-old girl with hereditary gingival fibromatosis. Gingival samples obtained from the upper anterior region were processed and examined with transmission electron microscope. RESULTS: In the case of Hunter syndrome due to the genetic lack of one lysosomal enzyme, an intercellular accumulation of glycosaminoglycans occurs. Within the gingiva of a patient with Hunter syndrome we observed membrane-bound storage vesicles in the cytoplasm of fibroblasts, endothelial cells of capillaries, surface epithelial cells, mast cells, and macrophages. Despite a long-term enzyme replacement therapy which improves clinical manifestations of Hunter syndrome, on the cellular level we still found marked accumulations of glycosaminoglycans in the cytoplasm of different cells as well as in the extracellular matrix. Hereditary gingival fibromatosis is a benign, slowly progressive and non-inflammatory gingival enlargement with a predominance of randomly oriented collagen fibrils in the gingival lamina propria. Some of these fibrils exhibited loops. Another unusual ultrastructural finding is the presence of empty perinuclear space in the cytoplasm of epithelial cells. The origin and significance of these non-membrane bound spaces are unknown. CONCLUSION: In both genetically determined diseases, the electron microscopic examination may be useful, and physicians get relevant information about the progress of illness.

Migration of titanium dioxide microparticles and nanoparticles through the body and deposition in the gingiva: an experimental study in rats.

The aim of this experimental work was to evaluate deposition of titanium dioxide (TiO2 ) microparticles and nanoparticles, which could originate from titanium bioimplants, in the gingiva. Wistar rats were injected intraperitoneally (i.p.) with a suspension of TiO2 particles of different sizes (150, 10, or 5 nm). The rats were killed 12 months post-injection, and the buccal and lingual gingivae were resected and evaluated using light and scanning electron microscopy. Energy-dispersive X-ray spectroscopy (EDS) was used to confirm the presence of titanium in deposits of microparticles and nanoparticles, and the concentration of titanium in tissues was measured using inductively coupled plasma-mass spectrometry (ICP-MS). Histological examination showed that all experimental groups exhibited agglomerates, in the gingiva, of titanium particles of micrometer size range, with no associated inflammatory response. Higher concentrations of titanium traces were shown, by ICP-MS, in both buccal and lingual tissues of all experimental groups compared with their matched controls. Titanium concentrations were significantly higher in the buccal gingiva than in the lingual gingiva, and after injection with 5-nm particles than with 10-nm particles in both localizations. Titanium microparticles and nanoparticles deposit in the gingiva, and mostly on the buccal side. Gingival deposition of titanium could be considered a tissue indicator of tribocorrosion processes of titanium bioimplants.

Scaling and Root Planning decreases the Number of Melanosomes within Keratinocytes in Human Gingiva: Ultrastructural Analysis of Three Cases.

AIM: The aim of the present report was to evaluate the number of melanosomes within keratinocytes on pigmented gingiva, after and before scaling and root planning. MATERIALS AND METHODS: Inflamed gingiva biopsies were taken from three patients (group 1). Forty days after scaling and root planning, biopsies were collected from the homologous contralateral areas (group 2). Samples were fixed in 2% glutaraldehyde-2.5% formaldehyde (freshly prepared from paraformaldehyde) in 0.1 M sodium cacodylate buffer, pH 7.4 for 4 hours, and then processed for transmission electron microscopy. Eighty electron micrographs were evaluated for recording the number of granules by a cross-section grid. The granules that were on intersections were recorded as well as the points that appeared on the cytoplasm for calculating the volumetric density (Vd), i.e the volume that the melanosomes occupied into the cytoplasm of keratinocytes. The presence of melanosomes in different stages of maturation and distribution into the cells were recorded with the aid of a magnifying glass. For the statistical analysis, a student t-test was applied. RESULTS: Results of the present report showed that melanosomes within keratinocytes were present in a higher number in inflamed gingiva A (11.08 ± 1.47), B (3.16 ± 0.38) and C (4.92 ± 0.89) and decreased after resolving of gingival inflammation A (9.46 ± 0.88), B (1.73 ± 0.25) and C (0.76 ± 0.18). CONCLUSION: There is a possibility that inflammation influences the intensity of gingival melanin pigmentation. CLINICAL SIGNIFICANCE: The periodontal treatment appears to have an effect on gingival melanin pigmentation.

[THE CHARACTERISTICS OF MORPHOLOGY OF BIOFILM OF PERIODONTIUM UNDER INFLAMMATORY DISEASES OF GUMS (CHRONIC CATARRHAL GINGIVITIS, CHRONIC PERIODONTITIS, CANDIDA-ASSOCIATED PERIODONTITIS) ACCORDING RESULTS OF ELECTRONIC MICROSCOPY].

The study was carried out to analyze morphology of biofilm of periodontium and to develop electronic microscopic criteria of differentiated diagnostic of inflammatory diseases of gums. The scanning electronic microscopy was applied to analyze samples of bioflm of periodont from 70 patients. Including ten patients with every nosologic form of groups with chronic catarrhal periodontitis. of light, mean and severe degree, chronic catarrhal gingivitis, Candida-associated paroperiodontitis and 20 healthy persons with intact periodontium. The analysis was implemented using dual-beam scanning electronic microscope Quanta 200 3D (FEI company, USA) and walk-through electronic micJEM 100B (JEOL, Japan). To detect marker DNA of periodont pathogenic bacteria in analyzed samples the kit of reagentsfor polymerase chain reaction "MultiDent-5" ("GenLab", Russia). The scanning electronic microscopy in combination with transmission electronic microscopy and polymerase chain reaction permits analyzing structure, composition and degree of development of biofilm of periodontium and to apply differentiated diagnostic of different nosologic forms of inflammatory diseases of periodontium, including light form of chronic periodontitis and gingivitis. The electronic microscopical indications of diseases ofperiodontium of inflammatory character are established: catarrhal gingivitis, (coccal morphological alternate), chronic periodontitis (bacillary morphological alternate), Candida-associated periodontitis (Candida morphological alternate of biofilm ofperiodontium).

Fractal analysis of ibuprofen effect on experimental dog peri-implantitis.

INTRODUCTION: The aim of this study was to assess the correlation between the fractal analysis of gingival changes and systemic nitro-oxidative stress in a short-term low-dose ibuprofen (IBU) treatment at experimental peri-implantitis (PI). MATERIALS AND METHODS: Six adult male mixed-breed dogs with PI were randomly treated for 2 weeks, 3 with IBU (5 mg/kg b.w.) and 3 with placebo. Clinical and radiological evaluation were performed. Gingival biopsies were assessed by light microscopy, transmission electron microscopy, and fractal analysis. Blood was collected to assay nitric oxide (NOx), total oxidative status (TOS), total antioxidant response (TAR), and oxidative stress index (OSI). RESULTS: Specific gingival ultrastructural alterations, bone loss, and systemic nitro-oxidative stress were evident in PI-placebo animals. IBU caused significant clinical, microscopic, fractal dimensions (P < 0.01), NOx, TOS, and OSI improvements. IBU caused no important bone and TAR changes. CONCLUSION: This study confirms that fractal analysis was a good method to assess the complex morphological changes and correlations with the nitro-oxidative stress in PI. Short-term low-dose IBU treatment consistently improved gingival status and reduced systemic nitro-oxidative stress.

[The dynamics of blood circulation in marginal gingiva after crown preparation by different ledge locations].

The periodontal tissue level may change after gingival margin retraction and tooth preparation. The aim of the study was to assess the influence of these manipulations on the condition of free gingival margin. The study included 53 persons (29 women and 24 men) divided into 4 groups followed-up for 6 to 8 weeks. Blood circulation in marginal gingiva of 118 teeth with healthy periodontal tissues was assessed by ultrasonic Doppler evaluation to reveal the circulation impairments in cervical margin after teeth crown preparation. The first group included 39 teeth, in which the gum was retracted by Roeko stay put non impregna cords ("Langenau", Germany). The second group included 39 teeth with shoulders prepared at the gingival margin; in the third group (40 teeth) the shoulder was located subgingivally. The fourth group (40 teeth) was control. The changes in recovery indices have been analyzed. The linear values were established as most significant and demonstrative. The indices variations and recovery period length depended on the coronal edge location. Statistically significant differences were found among all the groups (p>0.05). The results may be used to improve crown preparation for fixed dentures and decrease the recession rate of free gingival margin.

Ultrastructure of gingival epithelium in chronic gingivitis.

We studied ultrastructural reorganization of the gingival mucosa in chronic gingivitis. It was found that chronic inflammation leads to significant intracellular reorganization of epitheliocytes in the basal and prickle cell layers of gingival epithelium and their pronounced structural and functional heterogeneity. The main ultrastructural alterations of epitheliocytes in the basal and prickle cell layers include pronounced vacuolization of the perinuclear zone (partial necrosis), formation of thick tonofilament bundles, focal lysis and sequestration of glycogen, and destruction and reduction of intracellular junctions in some cases accompanied by acantholytic alterations. Chronic inflammation in the gingival mucosa induced extensive remodeling of the lamina propria manifested in multiplication of the basement membrane and obturation of blood vessels with collagen fibrils.

[Reaction of gingival mucosa on the biodegradated film under chronic periodontitis treatment: morpho-functional correlation].

Purpose - to study the morphological justification of biopolymer film on the gingival mucosa in chronic periodontitis. The samples of gingival mucosa from 42 patients with moderate degree of chronic periodontitis in the acute stage were researched. We determined the specific stomatologic indices of oral cavity and periodontal pocket depth. Treatment started with application to the gingiva biopolymer film with different ingredients (antibiotics etc.). Morphology and ultrastructure of epithelial component was investigated after 24 hours, 7 days and 3 months. Clinical indicators were estimated in the dynamics (24, 48 hours, 7-10 days, 3 months). Based on histo-ultrastructural data of strutified squamous epithelium and stomatologic indices of the oral cavity, we can conclude that the use of biodegradable polymer film leads to the regression of the process, reducing periodontal pocket depth, repair germinal and upper layers of epithelium, and in general, activates the reparative and regenerative processes in the gingival mucosa.

A proline rich protein from the gingival seal around teeth exhibits antimicrobial properties against Porphyromonas gingivalis.

The gingival seal around teeth prevents bacteria from destroying the tooth-supporting tissues and disseminating throughout the body. Porphyromonas gingivalis, a major periodontopathogen, degrades components of the specialized extracellular matrix that mediates attachment of the gingiva to the tooth. Of these, secretory calcium-binding phosphoprotein proline-glutamine rich 1 (SCPPPQ1) protein has a distinctive resistance to degradation, suggesting that it may offer resistance to bacterial attack. In silico analysis of its amino acid sequence was used to explore its molecular characteristics and to predict its two- and three-dimensional structure. SCPPPQ1 exhibits similarities with both proline-rich and cationic antimicrobial proteins, suggesting a putative antimicrobial potential. A combination of imaging approaches showed that incubation with 20 µM of purified SCPPPQ1 decrease bacterial number (p < 0.01). Fluorescence intensity decreased by 70% following a 2 h incubation of Porphyromonas gingivalis with the protein. Electron microscopy analyses revealed that SCPPPQ1 induced bacterial membrane disruption and breaches. While SCPPPQ1 has no effect on mammalian cells, our results suggest that it is bactericidal to Porphyromonas gingivalis, and that this protein, normally present in the gingival seal, may be exploited to maintain a healthy seal and prevent systemic dissemination of bacteria.

Hormonal influence on the physiology and pathology of the dental gingival unit: the preliminary results of a pilot study.

AIM: The effects of steroid hormones on the periodontium are most prominent at certain stages of a woman's life especially during the menstrual cycle when there is an increase in the secretion of sex hormones or a significant fluctuation in their concentration. The deterioration of existing periodontal conditions can be attributed to a fluctuation in the steroid hormones in circulation. By contributing to our understanding of periodontal changes caused by variation in hormone concentrations, this study aims to encourage the implementation in dental practice of the most suitable forms of treatment for hormone-related pathologies. METHODS: Tartar was removed from the teeth of five young women and four biopsies and blood tests were carried out on them at regular intervals. The information gathered was used to monitor periodontal changes arising from variation in hormone concentrations. RESULTS: The histological analysis of the test samples under an optical microscope did not reveal signs of inflammation, hyperaemia or oedema at any stage of the menstrual cycle in the patients examined. The extent of gingival Keratinization was found to be comparable to that present in the follicular phase. CONCLUSION: The occurrence of ovulation could not be shown in the pilot study. The histological analysis and the analysis of hormone concentrations show primarily the absence of surges in estradiol and LH which normally accompany ovulation; the levels recorded are similar to those found in the follicular phase.

Ex Vivo Evaluation of Gingival Ablation with Various Laser Systems and Electroscalpel.

Objective: The aim of this study was to perform a systematic and multifaceted comparison of thermal effects during soft tissue ablation with various lasers and an electroscalpel (ES). Materials and methods: Er:YAG, Er,Cr:YSGG, CO2, Diode, Nd:YAG lasers (1 W, pulsed or continuous wave), an ES, and a scalpel (Sc; control), were employed for porcine gingival tissue ablation. Temperature changes during ablation were measured by using an infrared thermal imaging camera and a thermocouple. After ablations, the wounds were observed using stereomicroscopy and scanning electron microscopy (SEM), and histological sections were analyzed. Compositional analysis was also performed on ablated sites by SEM wavelength dispersive X-ray spectroscopy. Results: The surface temperature during irradiation was highest with CO2 (over 500°C), followed by Diode (267°C) and Nd:YAG (258°C), Er:YAG (164°C), ES (135°C), and Er,Cr:YSGG (85°C). Carbonization was negligible (Er:YAG), slight (Er,Cr:YSGG), moderate (Nd:YAG and ES), and severe (CO2 and Diode). Under SEM observation, Er:YAG and Er,Cr:YSGG showed smooth surfaces but other devices resulted in rough appearances. Histologically, the coagulated and thermally affected layer was extremely minimal (38 µm in thickness) and free from epithelial collapse for Er:YAG. Compared with other devices, less compositional surface change was detected with Er:YAG and Er,Cr:YSGG; additionally, the use of water spray further minimized thermal influence. Conclusions: Among various power devices, Er:YAG laser showed the most efficient and refined gingival ablation with minimal thermal influence on the surrounding tissues. Er:YAG and Er,Cr:YSGG lasers with water spray could be considered as minimally invasive power devices for soft tissue surgery.

Mechanical properties of human oral mucosa tissues are site dependent: A combined biomechanical, histological and ultrastructural approach.

AIM: To investigate load-deformation properties of Thiel-embalmed human oral mucosa tissues and to compare three different anatomical regions in terms of mechanical, histological and ultrastructural characteristic with focus on the extracellular matrix. MATERIALS AND METHODS: Thirty specimens from three different regions of the oral cavity: attached gingiva, buccal mucosa and the hard palate were harvested from two Thiel-embalmed cadavers. Mechanical properties were obtained, combining strain evaluation and digital image correlation in a standardised approach. Elastic modulus, tensile strength, strain at maximum load and strain to failure were computed and analysed statistically. Subsamples were also analysed using scanning electron microscopy (SEM) and histological analysis. RESULTS: The highest elastic modulus of 37.36 ± 17.4 MPa was found in the attached gingiva group, followed by the hard palate and buccal mucosa. The elastic moduli of attached gingiva differed significantly to the buccal mucosa (p = .01) and hard palate (p = .021). However, there was no difference in the elastic moduli between the buccal mucosa and hard palate (p > .22). The tensile strength of the tissue samples ranged from 1.54 ± 0.5MPa to 3.81 ± 0.9 MPa, with a significant difference between gingiva group and buccal mucosa or hard palate (p = .001). No difference was found in the mean tensile strength between the buccal mucosa and hard palate (p = .92). Ultrastructural imaging yielded a morphological basis for the various mechanical properties found intraorally; the attached gingiva showed unidirectional collagen fibre network whereas the buccal mucosa and hard palate showed multi-directional network, which was more prone to tension failure and less elasticity. CONCLUSION: This is the first study assessing the various morphological-mechanical relationships of intraoral soft tissues, utilising Thiel-embalmed tissues. The findings of this study suggest that the tissues from different intraoral regions showed various morphological-mechanical behaviour which was also confirmed under the SEM and in the histological analysis.

TRPV2 expression in rat oral mucosa.

The oral mucosa is a highly specialised, stratified epithelium that confers protection from infection and physical, chemical and thermal stimuli. The non-keratinised junctional epithelium surrounds each tooth like a collar and is easily attacked by foreign substances from the oral sulcus. We found that TRPV2, a temperature-gated channel, is highly expressed in junctional epithelial cells, but not in oral sulcular epithelial cells or oral epithelial cells. Dual or triple immunolabelling with immunocompetent cell markers also revealed TRPV2 expression in Langerhans cells and in dendritic cells and macrophages. Electron microscopy disclosed TRPV2 immunoreactivity in the unmyelinated and thinly myelinated axons within the connective tissue underlying the epithelium. TRPV2 labelling was also observed in venule endothelial cells. The electron-dense immunoreaction in junctional epithelial cells, macrophages and neural axons occurred on the plasma membrane, on invaginations of the plasma membrane and in vesicular structures. Because TRPV2 has been shown to respond to temperature, hypotonicity and mechanical stimuli, gingival cells expressing TRPV2 may act as sensor cells, detecting changes in the physical and chemical environment, and may play a role in subsequent defence mechanisms.

Acellular dermal matrix graft for gingival augmentation: a preliminary clinical, histologic, and ultrastructural evaluation.

BACKGROUND: The aim of this study was to evaluate clinically, histologically, and ultrastructurally the integration process of the acellular dermal matrix used to increase the band of keratinized tissue while achieving gingival inflammation control. METHODS: Ten patients exhibiting a mucogingival problem with bands of keratinized tissue

[Cytological study of gum epithelium in connection with diabetes mellitus compensation stage].

The structure of interphased nuclei of gum's epithelium and inflammation of periodontal structure in patients with glycolitic disorders in coonection of degree compensation of diabetes mellitus were studied. In patients with diabetes mellitus and inflammation of gum mucosa 67,33+/-0,05% of gum's cells epithelium had morphology changes nuclei from the date of control group (50,99+/-0,05%) patients. This difference were more essential at deterioration of compensation (62,03+/-0,08%), sub - (67,05+/-0,05%), decompensate (75,11+/-0,07%) diabetes mellitus.

Ultrastructural and molecular-biological features of inflammatory-destructive processes in pathology of parodontal complex in children.

In children aged 11-15. under mild and moderate stage parodontitis the ultrastracture and Citokeratines 10/13 and 14 expression in epithelial lining of oral mucosa were analyzed: 1. in gingival epithelia 2. in alveolar processes epithelia. 14 cases without sings of inflammation serve as control tissue. Total number of cases - 33. After informed consent had been obtained, simples of histological tissue specimens were collected on surgical extraction of the tooth. In the control group decision on the tooth extraction was taken for the orthodontic causes. Our data indicate that: 1. Heterogenity is typical to the oral cavity epithelium: a) Ultrastructural signs of keratinization and dissociation, with typical high activity of the terminal differentiation marker cytokeratin 10/13, predominate in the keratinocytes of gingival mucosa. b) Cells with signs of germination activity predominate in the ultrastructure of mucosa alveolar processes. Such cells express cytokeratin 14, typical to nonkeratinized epithelium. 2. Tissue architectonics as well as protein contents of cytoskeleton (judging by cytokeratine expression) are speared in the parodontal pathology in children, however in contrast to alveolar mucosa, damage to the microcirculatory vessels is more pronounced in gingival mucosa. 3. Expression of cytokeratines 10/13 and 14 may indicate the process of lysis and reparation of periodontal ligament.

Ultrastructural evaluation of gingival glycosaminoglycans in ovariectomized rats: effects of steroid hormone therapy.

BACKGROUND/AIMS: To evaluate the behavior of glycosaminoglycans (GAGs) in rat gingiva and the effects of lack of sexual steroids and the hormonal therapy with estrogen and dexamethasone (DEX). METHODS: 40 female rats were divided into four groups: GI: animals in permanent estrus; GII: ovariectomized (OVX) animals + vehicle; GIII: OVX animals treated with 17beta-estradiol benzoate (10 microg/kg), and GIV: OVX animals treated with 17beta-estradiol benzoate (10 microg/kg) + DEX (3 mg/kg). After treatment, the gingiva was removed and its GAGs content was evaluated by electronic microscopy after stained by cuprolinic blue technique. RESULTS: The electron-microscopic data showed that low values of chondroitin sulfate were found in castrated animals (35.05 +/- 3.58%) compared to other groups (GI: 41.17 +/- 1.13; GIII: 48.04 +/- 2.60; GIV: 49.09 +/- 2.68%). In contrast, the amount of dermatan sulfate in GII (57.70 +/- 2.50%) was higher than in the other groups (GI: 46.12 +/- 1.30; GIII: 42.65 +/- 2.98; GIV: 42.68 +/- 5.43%). CONCLUSIONS: GAGs may be influenced by estradiol, and DEX did not seem to antagonize the role of estradiol in the GAGs of gingiva. The histotypical structure of gingiva is related to the amount of chondroitin sulfate. Consequently, the estrogen therapy may be important for gingival health.

A comparative study of the surfaces of normal oral epithelia and inflammatory hyperplasias by scanning electron microscopy.

The oral epithelia may show epithelial changes induced by the inflammation of the underlying lamina propria. Light microscopically, the epithelial changes are similar to epithelial dysplasia seen in a premalignant lesion. A scanning electron microscope permits a resolution higher than that of a light microscope. Therefore, it may elucidate the changes observed light microscopically. The purpose of this study was to examine the surface changes of the epithelia of parulides (gum boils) compared with those of normal oral epithelia to see if there were any surface changes due to the underlying inflammatory processes. A total of 3 specimens (1 buccal mucosa, 1 gingiva, and 1 hard palate) taken from 3 patients, one specimen from each patient, were used as controls. A total of 2 parulides from 2 patients, 1 specimen from each patient, were used as experimentals. Each specimen was cut in two. One half was prepared for light microscopy and the other half was prepared for scanning electron microscopy. Light microscopically, it was confirmed that the buccal mucosa was nonkeratinized, the gingiva was parakeratinized, and the hard palate was orthokeratinized. The epithelium of the parulis was nonkeratinized to parakeratinized with increased intercellular spaces and distinct epithelial changes similar to epithelial dysplasia. By scanning electron microscopy, the nonkeratinized mucosa (buccal mucosa) showed that most of the ridges ran parallel to each other and the parakeratinized mucosa (gingiva) and the orthokeratinized mucosa (hard palate) exhibited ridges surrounding uniform pits. The surface of the parulis of the first patient showed relatively smooth areas with residual pits, reminiscent of that of keratinized mucosa, and the surface of the parulis of the second patient showed relatively smooth areas with residual parallel ridges, reminiscent of that of nonkeratinized mucosa. Light microscopically, the oral epithelia overlying the intensely inflamed lamina propria showed distinct epithelial changes similar to epithelial dysplasia seen in a precancerous lesion but appeared normal except for markedly decreased numbers of microridges by scanning electron microscopy.

FTIR and SEM analysis applied in tissue engineering for root recovering surgery.

Gingival recession is defined by the displacement of the gingival margin in the apical direction, which overcomes the cementum enamel junction. The etiology of gingival retraction is related to tissue inflammation caused by the accumulation of biofilm, by trauma from brushing action. Aesthetic periodontal surgery aims to return the root coverage to aesthetic harmony, and reduce the risk of periodontal disease and caries. To assist in the root coverage process, the porcine collagen matrix (PCM) has been widely studied. The objectives of this study are to identify the types of collagen that make up the PCM and analyze their morphology. For this, five PCM fragments, 2 mm (thickness) × 2.6 mm (width), were analyzed with the aid of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The analysis by SEM showed that the PCM consists of two layers; the surface layer is compact, low porosity, and smooth surface, and a foamed underlying layer has high porosity. Through FTIR we identified that the surface and underlying layers are composed of collagen types I and III, respectively. This biomaterial is conducive to root coverage; it allows adsorption and cell proliferation following the matrix resorption and periodontal tissue neoformation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1326-1329, 2017.