Oral exfoliative cytology and corrosion of metal piercings. Tissue implications.

OBJECTIVES: A group of adolescents with oral piercings was studied to determine the presence of metallic particles in cells exfoliated from the mucosa surrounding their metal oral piercings and the association between such particles and the metal jewelry, and to evaluate subsequent tissue implications. MATERIALS AND METHODS: Sixteen teenage patients who had tongue and/or lip piercings were included. The clinical features of the oral mucosa and lip skin were evaluated. Exfoliative cytology was performed in the area surrounding the piercing. The surface of used and unused jewelry was studied by scanning electron microscopy and energy dispersive X-ray analysis. RESULTS: Hyperplastic, leukoedematous, and lichenoid lesions were observed in the mucosa, as well as lesions associated with metallosis of the lip skin. Cytological smears showed the presence of particles inside the epithelial cells; the particles were found to contain aluminum, tungsten, and molybdenum. In one case requiring surgical removal of the piercing, histological examination of the tissue associated with the piece of jewelry showed the presence particles containing aluminum, iron, and tin inside multinucleated giant cells. Although surface finish defects were observed on both unused and used piercing jewelry, they were more evident on the used pieces. CONCLUSIONS: Ion particles are released from the metal piercings and could have been adjuvant factors in the development of the observed lesions. Cells exfoliated from the oral mucosa surrounding metal piercings may serve as bioindicators of corrosion processes. CLINICAL RELEVANCE: We propose the use of exfoliative cytology to monitor corrosion processes and for routine clinical follow up.

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.

Effects of saliva on early post-tooth extraction tissue repair in rats.

The aim of the present study was to perform a biochemical, histological, and histomorphometrical evaluation of the mechanisms involved in tissue repair in rats subjected to submandibulectomy-induced hyposialia, 24, 48, and 72 hours of post-tooth extraction. We studied the correlation between the lack of submandibular saliva and the modulation of inflammatory mediators involved in tissue repair, such as prostaglandin E2 , nitric oxide (NO), and tumor necrosis factor alpha (TNF-α). Rats with hyposialia showed a delay in socket healing, slow replacement of the clot with granulation tissue, and fewer cells and collagen fibers, concomitant with a longer inflammatory process, as compared to controls. The lack of saliva induced by submandibulectomy modified the levels of prostaglandin E2 , NO, and TNF-α, and tissue response in the early stages of wound healing compared to controls, and could thus determine alterations in later osteogenic response. Our results allow concluding that hyposialia modulates the parameters of inflammation studied here, and that it is essential for optimal healing. Therefore, these findings provide evidence for the importance of submandibular saliva to final bone socket healing.

Histologic and histomorphometric study of bone repair under acute Trypanosoma cruzi infection in rats.

Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanosomiasis (Chagas disease). The aim of this study was to evaluate the histopathological effects of acute infection by T. cruzi on bone repair, Wistar rats were used throughout. The animals were assigned to two groups: Control Group (CG n =20) and Experimental Group (EG n = 20). All the animals were anesthetized, at to the first lower right molar was extracted. The EG animals were inoculated subcutaneously at to with 0.1 mL of 10 trypomastigotes of the virulent strain Tulahuen of T. cruzi. The CG animals were administered an equivalent volume ofsaline solution subcutaneously. The animals in both groups were euthanized at 15 days post-infection and tooth extraction. The mandibles were resected, fixed informalin solution, radiographed, decalcified and embedded in paraffin. Bucco-lingually oriented sections were obtained at the level of the mesial tooth socket of the first lower molar and stained with hematoxylin-eosin. Total alveolar volume (TV) and bone volume (TBV/TV) in the apical third of the tooth socket were evaluated histomorphometrically. The histological analysis revealed an alteration in post-extraction bone tissue repair in animals infected by T. cruzi. A reduction in osteogenic activity was observed concomitant with a rise in quiescent and eroded bone surfaces. Histomorphometric evaluation revealed a significant reduction (19%) in total alveolar volume (TV) and bone volume (TBV/TV) (24%) in the apical third of the tooth socket in animals infected with T. cruzi in comparison to non-infected animals (p<0.05). The results obtained using this experimental model showed decreased osteogenesis in bone tissue repair under acute Trypanosoma cruzi infection in rats.

Histologic and histomorphometric study of bone repair under acute Trypanosoma cruzi infection in rats

Trypanosoma cruzi (T. cruzi) is an intracellular protozoan pathogen that causes American trypanosomiasis (Chagas disease). The aim of this study was to evaluate the histopathological effects of acute infection by T. cruzi on bone repair. Wistar rats were used throughout. The animals were assigned to two groups: Control Group (CG n =20) and Experimental Group (EG n =20). All the animals were anesthetized, at t0 the first lower right molar was extracted. The EG animals were inoculated subcutaneously at t0 with 0.1 mL of 105 trypomastigotes of the virulent strain Tulahuen of T. cruzi. The CG animals were administered an equivalent volume of saline solution subcutaneously. The animals in both groups were euthanized at 15 days post-infection and tooth extraction. The mandibles were resected, fixed in formalin solution, radiographed, decalcified and embedded in paraffin. Bucco-lingually oriented sections were obtained at the level of the mesial tooth socket of the first lower molar, and stained with hematoxylin-eosin. Total alveolar volume (TV) and bone volume (TBV/TV) in the apical third of the tooth socket were evaluated histomorphometrically. The histological analysis revealed an alteration in post-extraction bone tissue repair in animals infected by T. cruzi. A reduction in osteogenic activity was observed concomitant with a rise in quiescent and eroded bone surfaces. Histomorphometric evaluation revealed a significant reduction (19%) in total alveolar volume (TV) and bone volume (TBV/TV) (24%) in the apical third of the tooth socket in animals infected with T. cruzi in comparison to non-infected animals (p<0.05). The results obtained using this experimental model showed decreased osteogenesis in bone tissue repair under acute Trypanosoma cruzi infection in rats.

El Trypanosoma cruzi (T. cruzi) es un protozoario intracelular que causa Trypanosomoniasis Americana (Enfermedad de Chagas). El objetivo del presente trabajo fue el estudio histopatologico del efecto de la infeccion aguda por Trypanosoma cruzi sobre la reparacion del tejido oseo. Se utilizaron ratas Wistar macho que fueron asignadas a dos grupos: Grupo Control (GC n =20) y Grupo Experimental (GE n =20). Los animales de ambos grupos, bajo anestesia general intraperitoneal, fueron sometidos a t0, a exodoncia del primer molar inferior derecho, en el GE fueron inoculados,a t0 por via subcutanea en la region inguinal izquierda con 0.1 mL de 105 tripomastigotes de la cepa virulenta Tulahuen de Trypanosoma cruzi. A los animales del GC se les administro el volumen equivalente de solucion salina por via subcutanea. A los animales de ambos grupos se les practico la eutanasia a los 15 dias. Se resecaron las mandibulas, se fijaron en solucion de formol al 10%, se radiografiaron, se descalcificaron y se incluyeron en parafina. Se obtuvieron cortes orientados en sentido vestibulo-lingual a nivel del alveolo mesial del primer molar inferior derecho y se colorearon con hematoxilina-eosina para su posterior estudio histologico e histomorfometrico. Histologicamente se observo una menor actividad osteogenica a expensas de un incremento de las superficies quiescentes y de las superficies erosivas en el GE. En la evaluacion histomorfometrica se detecto disminucion estadiasticamente significativa del volumen oseo total (19%) y del volumen trabecular en el tercio apical del alveolo (24%) en el GE con respecto al GC (p<0.05). Los resultados obtenidos en este modelo experimental evidencian una disminucion de la osteogenesis en la reparacion osea en ratas con infeccion aguda por Trypanosoma cruzi.

Osteoconductivity of strontium-doped bioactive glass particles: a histomorphometric study in rats.

There is accumulating evidence that strontium (Sr)-containing bioceramics have positive effects on bone tissue repair. The aims of the present study were to evaluate the osteoconductivity of Sr-doped bioactive glass (BG) particles implanted in rat tibia bone marrow, and characterize the neoformed bone tissue by SEM-energy-dispersive X-ray microanalysis. Melt-derived BGs were prepared from a base 45S5 BG. Sr-doped glass (45S5.6Sr) was prepared using 6 wt % SrO as a substitute for the CaO. Histological analysis using undecalcified sections showed that new lamellar bone had formed along the surface of both 45S5 and 45S5.6Sr BG particles within 4 weeks. To evaluate osteoconductivity, affinity indices were calculated. At 30 days after implantation, 45S5 and 45S5.6Sr BGs had almost identical affinity indices (88% +/- 7% and 87% +/- 9%; p > 0.05). Strontium was not detected in the neoformed bone tissue surrounding 45S5.6Sr BG particles. These results indicate that 45S5.6Sr BG particles are osteoconductive when implanted inside the intramedullary canal of rat tibiae, and no alterations in bone mineralization, in terms of Ca/P ratio, were observed in the neoformed bone tissue around 45S5.6Sr BG particles.

Histomorphometric study of alveolar bone healing in rats fed a boron-deficient diet.

Bone healing after tooth extraction in rats is a suitable experimental model to study bone formation. Thus, we performed a study to determine the effects of boron (B) deficiency on bone healing by using this model. The first lower right molar of weanling Wistar rats was extracted under anesthesia. The animals were divided into two groups: +B (adequate; 3 mg B/kg diet), and -B (boron-deficient; 0.07 mg/kg diet). The animals in both groups were killed in groups of 10 at 7 and 14 days after surgery. The guidelines of the NIH for the care and use of laboratory animals were observed. The mandibles were resected, fixed, decalcified, and embedded in paraffin. Buccolingually oriented sections were obtained at the level of the mesial alveolus and used for histometric evaluations. Total alveolar volume (TAV) and trabecular bone volume per total volume (BV/TV) in the apical third of the alveolus were determined. Percentages of osteoblast surface (ObS), eroded surface (ES), and quiescent surface (QS) were determined. No statistical significant differences in food intake and body weight were observed. Histomorphometric evaluation found -B rats had 36% and 63% reductions in BV/TV at 7 and 14 days, respectively. When compared with +B rats, -B rats had significant reductions (57% and 87%) in ObS concomitantly with increases (120% and 126%) in QS at 7 and 14 days, respectively. The findings show that boron deficiency results in altered bone healing because of a marked reduction in osteogenesis.

A histomorphometric study of alveolar bone modelling and remodelling in mice fed a boron-deficient diet.

OBJECTIVE: Emerging evidence indicates that boron (B) plays a role in bone formation and maintenance. Thus, a study was performed to determine whether dietary B-deficiency affects periodontal alveolar bone modelling and remodelling. DESIGN: Weanling Swiss mice (n=30) were divided into three groups: control diet (GI, 3mg B/kg); B-deficient diet (GII, 0.07 mg B/kg); and pair-fed with GII (GIII). The animals were maintained on their respective diets for 9 weeks and then sacrificed. The guidelines of the NIH for the care and use of laboratory animals were observed. The mandibles were resected, fixed, decalcified in 10% EDTA and embedded in paraffin. Buccolingually oriented sections were obtained at the level of the mesial root of the first lower molar and stained with H-E. Histomorphometric studies were performed separately on the buccal and lingual sides of the periodontal alveolar bone. Percentages of osteoblast surfaces (ObSs), eroded surfaces (ESs), and quiescent surfaces (QSs) were determined. RESULTS: No statistically significant differences in food intake and body weight were observed between the groups. When compared with GI and GIII mice, GII mice (B-deficient) had 63% and 48% reductions in ObS and 58% and 73% increases in QS in buccal and lingual plates, respectively. ES were not affected by B nutriture. CONCLUSION: The results are evidence that dietary boron deprivation in mice alters periodontal alveolar bone modelling and remodelling by inhibiting bone formation.

A histomorphometric study of alveolar bone modeling and remodeling under experimental anaemia and polycythaemia in rats.

UNLABELLED: Alveolar bone is the least stable of the periodontal tissues, because it is subjected to continuous modeling and remodeling. OBJECTIVE: To perform a histological and histomorphometric evaluation of bone modeling and remodeling of periodontal alveolar bone under experimental anaemia and polycythaemia. METHODS: Thirty Wistar rats were divided into three groups: control (C), animals were i.p. injected with 0.5 mL of saline solution; anaemia (A), animals were injected with 6 mg/100 b.w. of phenylhydrazine every 48 h; polycythaemia (P), animals were transfused with 2.5 mL/100 b.w. of 80% suspension of homologous erythrocytes. All the animals were sacrificed 14 days after the onset of the experiment. The mandibles were resected, fixed in formalin, radiographed, processed and embedded in paraffin. Bucco-lingually oriented sections were obtained at the level of the mesial root of the first lower molar, and stained with hematoxylin-eosin. Histological and histomorphometric studies were performed on the buccal and lingual plates of periodontal alveolar bone. RESULTS: Histological and histomorphometric studies showed a statistically significant decrease in bone formation both in buccal and lingual plates in group A (anaemia) as compared to group C (control). An increase in active bone formation was found in the lingual plate in group P (polycythaemia) as compared to group C (control). CONCLUSION: The results obtained using this experimental model evidenced alterations in bone modeling and remodeling under conditions of anaemia and polycythaemia and/or associated factors.

Alveolar bone response in an experimental model of renal failure and periodontal disease: a histomorphometric and histochemical study.

BACKGROUND: Chronic destructive periodontal disease is characterized by gingival inflammation, periodontal pocket formation, and bacterial plaque that lead to alveolar bone destruction. Polymorphonuclear neutrophil leukocytes (PMNs) are the first line of defense against infection caused by dental plaque bacteria. Renal patients present functional abnormalities of PMN, including impaired chemotaxis, phagocytosis, and intracellular killing of bacteria. In view of the above, the aim of this work was to evaluate the effect of renal failure on bone damaged by periodontal disease using histomorphometric and histochemical parameters. METHODS: Twenty male Wistar rats weighing 250 g were assigned to one of the following four groups: 1) control (no treatment); 2) renal failure (RF); 3) periodontal disease (PD); and 4) renal failure plus periodontal disease (RF+PD). All the animals were sacrificed 31 days after the onset of the experiment. Mesio-distally oriented sections of the first lower molar were obtained for histomorphometric and histochemical evaluation. RESULTS: Total erosion, active erosion, and total number of tartrate-resistant acid phosphatase-positive (TRAP+) osteoclasts were found to be increased in the RF+PD group compared with the PD group. CONCLUSION: Our results demonstrate increased bone resorption in animals with untreated renal failure and periodontal disease, and thus indicate that the release of different factors by inflammatory cells is magnified, accelerating the progression of the disease in this animal model.