Tammy Steimetz | Universidad de Buenos Aires (original) (raw)
Papers by Tammy Steimetz
PubMed, 2012
Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanoso... more 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.
PubMed, 1997
The work presented herein, is an experimental study on the effect of an orthodontic appliance wit... more The work presented herein, is an experimental study on the effect of an orthodontic appliance with a helicoidal spring designed to exert force toward palatine--i.e. in the opposite direction to the natural vestibular drift--on a bone remodelling surface. The appliance consists of two stainless steel molar bands, with a horizontal bracket tube welded to their palatal aspect through which the arms of the helicoidal spring are passed. Wistar rats, 250 g body weight, were fitted with the device for 48 and 96 hours. One group of rats was administered two doses of tetracycline hydrochloride prior to device placement, in order to label mineralizing fronts. Histomorphometric studies of the periodontal wall of the palatine alveolar bone showed a marked increase of bone resorption at both experimental time points together with an increase in the number of osteoclasts, and no tetracycline labelling after 48 hours. The results show that compressive forces are capable of stimulating resorption, even on bone modelling surfaces. The pressure applied would stimulate osteoblasts to send out signals for osteoclast recruitment and activity.
PubMed, 1996
The design of an original appliance to achieve mesial movement of the first upper molar on one si... more The design of an original appliance to achieve mesial movement of the first upper molar on one side in rat is presented. The appliance is constructed in 0.4 mm stainless steel wire forming a parallelepiped 3 mm in width in its anterior sector, 4 mm in width in its posterior sector and 12 mm in length in its lateral branches. In addition a central longitudinal bar is welded to the structure. The lateral branches of the appliance slide freely through the tubes welded to the palatal aspect of the molar bands, cemented in turn to both first molars. A wire 2 mm in length is welded in the anchorage area to the mesial side of the molar tube at 3 mm from the anterior end of the appliance, which acts as a butt. A pre-formed nickel-titanium open coil spring 0.23 mm thick, lumen 0.60 mm and 5.00 mm in length is placed distal to the molar tube. The spring is compressed by 1 mm of its original length, the final force being approximately 50 g. The movement achieved was measured on plaster casts obtained from pre and postoperative impressions, and afforded values of 0.250 mm +/- 0.790 mm on the active side and 0.012 +/- 0.011 mm on the passive side. The histologic studies showed an extensive erosive area on the pressure side of the alveolar wall. The appliance presented will be useful to achieve models of experimental movements of only one molar towards mesial with a force of known magnitude.
European Journal of Oral Sciences, May 14, 2015
Migration of titanium dioxide microparticles and nanoparticles through the body and deposition in... more Migration of titanium dioxide microparticles and nanoparticles through the body and deposition in the gingiva: an experimental study in rats.
Journal of Periodontology, Dec 1, 2003
Background: Chronic destructive periodontal disease is characterized by gingival inflammation, pe... more 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.
Functional Foods in Health and Disease, Dec 21, 2021
Background: Curcumin (Cur) is a natural yellow polyphenol extracted from the turmeric rhizome (Cu... more Background: Curcumin (Cur) is a natural yellow polyphenol extracted from the turmeric rhizome (Curcuma longa). Cur is known for its potential therapeutic properties as an analgesic, anti-inflammatory, antioxidant, antimicrobial, hepatoprotective, and anti-mutagenic, although some of these biological activities remain unproven. Epidemiological studies have shown a positive relationship between high-fat diets and diet-related chronic diseases. We hypothesized that some adverse effects of consuming atherogenic or high-fat diets (AD) can be ameliorated by Cur supplementation. Using an experimental model of rats, this study investigated the significance of Cur when it is given as a supplement in an AD.
Clinical Oral Investigations, Sep 17, 2018
Objectives A group of adolescents with oral piercings was studied to determine the presence of me... more 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.
Journal of Biomedical Materials Research Part A, 2010
There is accumulating evidence that strontium (Sr)‐containing bioceramics have positive effects o... more 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. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Archives of Oral Biology, Jul 1, 2008
Alveolar bone is the most malleable of the periodontal tissues, because it is subjected to contin... more Alveolar bone is the most malleable of the periodontal tissues, because it is subjected to continuous modelling and remodelling associated with tooth eruption and functional requirements. 1-3 Furthermore, the environment influences healthy and diseased periodontal tissues. 3,4 It has been stated that diet and nutrition are major multifactorial environmental factors in the etiology and pathogenesis of craniofacial disorders, i.e. periodontal diseases. 5-7 a r c h i v e s o f o r a l b i o l o g y 5 3
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2008
Bone healing after tooth extraction in rats is a suitable experimental model to study bone format... more 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: 1B (adequate; 3 mg B/kg diet), and 2B (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 2B rats had 36% and 63% reductions in BV/TV at 7 and 14 days, respectively. When compared with 1B rats, 2B 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.
Wound Repair and Regeneration, Mar 1, 2015
The aim of the present study was to perform a biochemical, histological and histomorphometrical e... more 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 h 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 E 2 , nitric oxide, 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 E 2 , nitric oxide 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.
The purpose of this study was to analyze whether the position of the tooth in the alveolar ridge ... more The purpose of this study was to analyze whether the position of the tooth in the alveolar ridge influences the thickness of the facial bone wall and the distance between the cementoenamel junction (CEJ) and osseous zenith (OZ). Conebeam computed tomography (CBCT) scans from fifty four dentate patients were included in the study (22 male and 32 female, mean age 41.5 years). The measurements taken included: (1).The Facial bone thickness at 7 different equidistant levels measuring levels (ML 17) between OZ and the root apex (A). (2) The CEJ OZ distance. (3) Facial position of the tooth (FPT) relative to a straight line traced from mesial to distal interproximal depressions of the alveolar plate at the level of the CEJ. The Facial bone wall thickness ranged between 0 mm and 3.8 mm, with greater values at more apical levels. Mean values were smaller than 1 mm at every level except ML7. The CEJ OZ distance varied between 0.5 mm and 6.9 mm (mean 2.9 mm). The Mean of FPT value was...
Functional Foods in Health and Disease, 2021
Background: Curcumin (Cur) is a natural yellow polyphenol extracted from the turmeric rhizome (Cu... more Background: Curcumin (Cur) is a natural yellow polyphenol extracted from the turmeric rhizome (Curcuma longa). Cur is known for its potential therapeutic properties as an analgesic, anti-inflammatory, antioxidant, antimicrobial, hepatoprotective, and anti-mutagenic, although some of these biological activities remain unproven. Epidemiological studies have shown a positive relationship between high-fat diets and diet-related chronic diseases. We hypothesized that some adverse effects of consuming atherogenic or high-fat diets (AD) can be ameliorated by Cur supplementation. Using an experimental model of rats, this study investigated the significance of Cur when it is given as a supplement in an AD.Methods: Healthy adult Wistar rats were randomly assigned to one of three groups. Controls (C) received a standard diet and experimental rats were fed with AD or AD+Cur for 5 weeks. Cur (100 mg/kg body weight) was given orally daily, plus piperine (5 mg/kg body weight). The effect of Cur su...
POLÍTICA EDITORIAL El objetivo de Acta Odontológica Latinoamericana (AOL) es ofrecer a la comunid... more POLÍTICA EDITORIAL El objetivo de Acta Odontológica Latinoamericana (AOL) es ofrecer a la comunidad científica un medio adecuado para la difusión internacional de los tra-bajos de investigación, realizados prefe-rentemente en Latinoamérica, dentro del campo odontológico y áreas estrechamen-te relacionadas. Publicará trabajos origi-nales de investigación básica, clínica y epidemiológica, tanto del campo biológi-co como del área de materiales dentales y técnicas especiales. La publicación de tra-bajos clínicos será considerada siempre que tengan contenido original y no sean meras presentaciones de casos o series. En principio, no se aceptarán trabajos de revi-sión bibliográfica, si bien los editores podrán solicitar revisiones de temas de particular interés. Las Comunicaciones Breves, dentro del área de interés de AOL, serán consideradas para su publicación. Solamente se aceptarán trabajos no publi-cados anteriormente, los cuales no podrán ser luego publicados en otro medio sin expres...
European Journal of Oral Sciences, 2015
The aim of this experimental work was to evaluate deposition of titanium dioxide (TiO2 ) micropar... more 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.
RESUMEN El Trypanosoma cruzi (T. cruzi) es un protozoario intracelular que causa Trypanosomoniasi... more RESUMEN El Trypanosoma cruzi (T. cruzi) es un protozoario intracelular que causa Trypanosomoniasis Americana (Enfermedad de Chagas). El objetivo del presente trabajo fue el estudio histo-patológico del efecto de la infección aguda por Trypanosoma cruzi sobre la reparación del tejido óseo. 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 t 0 , a exodoncia del primer molar inferior derecho, en el GE fueron inoculados,a t 0 por vía subcutánea en la región inguinal izquierda con 0.1 mL de 10 5 tripomastigotes de la cepa virulenta Tulahuén de Trypanoso-ma cruzi. A los animales del GC se les administró el volumen equivalente de solución salina por vía subcutánea. A los ani-males de ambos grupos se les practicó la eutanasia a los 15 días. Se resecaron las mandíbulas, se fijaron en solución de formol al 10%, se radiografiaron, ...
Acta odontologica latinoamericana : AOL, 2012
Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanoso... more 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 stain...
Acta Odontologica Latinoamericana Aol, 2012
Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanoso... more 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&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The results obtained using this experimental model showed decreased osteogenesis in bone tissue repair under acute Trypanosoma cruzi infection in rats.
Clinical oral investigations, Jan 17, 2018
A group of adolescents with oral piercings was studied to determine the presence of metallic part... more 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. 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. 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...
PubMed, 2012
Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanoso... more 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.
PubMed, 1997
The work presented herein, is an experimental study on the effect of an orthodontic appliance wit... more The work presented herein, is an experimental study on the effect of an orthodontic appliance with a helicoidal spring designed to exert force toward palatine--i.e. in the opposite direction to the natural vestibular drift--on a bone remodelling surface. The appliance consists of two stainless steel molar bands, with a horizontal bracket tube welded to their palatal aspect through which the arms of the helicoidal spring are passed. Wistar rats, 250 g body weight, were fitted with the device for 48 and 96 hours. One group of rats was administered two doses of tetracycline hydrochloride prior to device placement, in order to label mineralizing fronts. Histomorphometric studies of the periodontal wall of the palatine alveolar bone showed a marked increase of bone resorption at both experimental time points together with an increase in the number of osteoclasts, and no tetracycline labelling after 48 hours. The results show that compressive forces are capable of stimulating resorption, even on bone modelling surfaces. The pressure applied would stimulate osteoblasts to send out signals for osteoclast recruitment and activity.
PubMed, 1996
The design of an original appliance to achieve mesial movement of the first upper molar on one si... more The design of an original appliance to achieve mesial movement of the first upper molar on one side in rat is presented. The appliance is constructed in 0.4 mm stainless steel wire forming a parallelepiped 3 mm in width in its anterior sector, 4 mm in width in its posterior sector and 12 mm in length in its lateral branches. In addition a central longitudinal bar is welded to the structure. The lateral branches of the appliance slide freely through the tubes welded to the palatal aspect of the molar bands, cemented in turn to both first molars. A wire 2 mm in length is welded in the anchorage area to the mesial side of the molar tube at 3 mm from the anterior end of the appliance, which acts as a butt. A pre-formed nickel-titanium open coil spring 0.23 mm thick, lumen 0.60 mm and 5.00 mm in length is placed distal to the molar tube. The spring is compressed by 1 mm of its original length, the final force being approximately 50 g. The movement achieved was measured on plaster casts obtained from pre and postoperative impressions, and afforded values of 0.250 mm +/- 0.790 mm on the active side and 0.012 +/- 0.011 mm on the passive side. The histologic studies showed an extensive erosive area on the pressure side of the alveolar wall. The appliance presented will be useful to achieve models of experimental movements of only one molar towards mesial with a force of known magnitude.
European Journal of Oral Sciences, May 14, 2015
Migration of titanium dioxide microparticles and nanoparticles through the body and deposition in... more Migration of titanium dioxide microparticles and nanoparticles through the body and deposition in the gingiva: an experimental study in rats.
Journal of Periodontology, Dec 1, 2003
Background: Chronic destructive periodontal disease is characterized by gingival inflammation, pe... more 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.
Functional Foods in Health and Disease, Dec 21, 2021
Background: Curcumin (Cur) is a natural yellow polyphenol extracted from the turmeric rhizome (Cu... more Background: Curcumin (Cur) is a natural yellow polyphenol extracted from the turmeric rhizome (Curcuma longa). Cur is known for its potential therapeutic properties as an analgesic, anti-inflammatory, antioxidant, antimicrobial, hepatoprotective, and anti-mutagenic, although some of these biological activities remain unproven. Epidemiological studies have shown a positive relationship between high-fat diets and diet-related chronic diseases. We hypothesized that some adverse effects of consuming atherogenic or high-fat diets (AD) can be ameliorated by Cur supplementation. Using an experimental model of rats, this study investigated the significance of Cur when it is given as a supplement in an AD.
Clinical Oral Investigations, Sep 17, 2018
Objectives A group of adolescents with oral piercings was studied to determine the presence of me... more 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.
Journal of Biomedical Materials Research Part A, 2010
There is accumulating evidence that strontium (Sr)‐containing bioceramics have positive effects o... more 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. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Archives of Oral Biology, Jul 1, 2008
Alveolar bone is the most malleable of the periodontal tissues, because it is subjected to contin... more Alveolar bone is the most malleable of the periodontal tissues, because it is subjected to continuous modelling and remodelling associated with tooth eruption and functional requirements. 1-3 Furthermore, the environment influences healthy and diseased periodontal tissues. 3,4 It has been stated that diet and nutrition are major multifactorial environmental factors in the etiology and pathogenesis of craniofacial disorders, i.e. periodontal diseases. 5-7 a r c h i v e s o f o r a l b i o l o g y 5 3
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2008
Bone healing after tooth extraction in rats is a suitable experimental model to study bone format... more 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: 1B (adequate; 3 mg B/kg diet), and 2B (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 2B rats had 36% and 63% reductions in BV/TV at 7 and 14 days, respectively. When compared with 1B rats, 2B 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.
Wound Repair and Regeneration, Mar 1, 2015
The aim of the present study was to perform a biochemical, histological and histomorphometrical e... more 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 h 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 E 2 , nitric oxide, 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 E 2 , nitric oxide 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.
The purpose of this study was to analyze whether the position of the tooth in the alveolar ridge ... more The purpose of this study was to analyze whether the position of the tooth in the alveolar ridge influences the thickness of the facial bone wall and the distance between the cementoenamel junction (CEJ) and osseous zenith (OZ). Conebeam computed tomography (CBCT) scans from fifty four dentate patients were included in the study (22 male and 32 female, mean age 41.5 years). The measurements taken included: (1).The Facial bone thickness at 7 different equidistant levels measuring levels (ML 17) between OZ and the root apex (A). (2) The CEJ OZ distance. (3) Facial position of the tooth (FPT) relative to a straight line traced from mesial to distal interproximal depressions of the alveolar plate at the level of the CEJ. The Facial bone wall thickness ranged between 0 mm and 3.8 mm, with greater values at more apical levels. Mean values were smaller than 1 mm at every level except ML7. The CEJ OZ distance varied between 0.5 mm and 6.9 mm (mean 2.9 mm). The Mean of FPT value was...
Functional Foods in Health and Disease, 2021
Background: Curcumin (Cur) is a natural yellow polyphenol extracted from the turmeric rhizome (Cu... more Background: Curcumin (Cur) is a natural yellow polyphenol extracted from the turmeric rhizome (Curcuma longa). Cur is known for its potential therapeutic properties as an analgesic, anti-inflammatory, antioxidant, antimicrobial, hepatoprotective, and anti-mutagenic, although some of these biological activities remain unproven. Epidemiological studies have shown a positive relationship between high-fat diets and diet-related chronic diseases. We hypothesized that some adverse effects of consuming atherogenic or high-fat diets (AD) can be ameliorated by Cur supplementation. Using an experimental model of rats, this study investigated the significance of Cur when it is given as a supplement in an AD.Methods: Healthy adult Wistar rats were randomly assigned to one of three groups. Controls (C) received a standard diet and experimental rats were fed with AD or AD+Cur for 5 weeks. Cur (100 mg/kg body weight) was given orally daily, plus piperine (5 mg/kg body weight). The effect of Cur su...
POLÍTICA EDITORIAL El objetivo de Acta Odontológica Latinoamericana (AOL) es ofrecer a la comunid... more POLÍTICA EDITORIAL El objetivo de Acta Odontológica Latinoamericana (AOL) es ofrecer a la comunidad científica un medio adecuado para la difusión internacional de los tra-bajos de investigación, realizados prefe-rentemente en Latinoamérica, dentro del campo odontológico y áreas estrechamen-te relacionadas. Publicará trabajos origi-nales de investigación básica, clínica y epidemiológica, tanto del campo biológi-co como del área de materiales dentales y técnicas especiales. La publicación de tra-bajos clínicos será considerada siempre que tengan contenido original y no sean meras presentaciones de casos o series. En principio, no se aceptarán trabajos de revi-sión bibliográfica, si bien los editores podrán solicitar revisiones de temas de particular interés. Las Comunicaciones Breves, dentro del área de interés de AOL, serán consideradas para su publicación. Solamente se aceptarán trabajos no publi-cados anteriormente, los cuales no podrán ser luego publicados en otro medio sin expres...
European Journal of Oral Sciences, 2015
The aim of this experimental work was to evaluate deposition of titanium dioxide (TiO2 ) micropar... more 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.
RESUMEN El Trypanosoma cruzi (T. cruzi) es un protozoario intracelular que causa Trypanosomoniasi... more RESUMEN El Trypanosoma cruzi (T. cruzi) es un protozoario intracelular que causa Trypanosomoniasis Americana (Enfermedad de Chagas). El objetivo del presente trabajo fue el estudio histo-patológico del efecto de la infección aguda por Trypanosoma cruzi sobre la reparación del tejido óseo. 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 t 0 , a exodoncia del primer molar inferior derecho, en el GE fueron inoculados,a t 0 por vía subcutánea en la región inguinal izquierda con 0.1 mL de 10 5 tripomastigotes de la cepa virulenta Tulahuén de Trypanoso-ma cruzi. A los animales del GC se les administró el volumen equivalente de solución salina por vía subcutánea. A los ani-males de ambos grupos se les practicó la eutanasia a los 15 días. Se resecaron las mandíbulas, se fijaron en solución de formol al 10%, se radiografiaron, ...
Acta odontologica latinoamericana : AOL, 2012
Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanoso... more 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 stain...
Acta Odontologica Latinoamericana Aol, 2012
Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanoso... more 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&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The results obtained using this experimental model showed decreased osteogenesis in bone tissue repair under acute Trypanosoma cruzi infection in rats.
Clinical oral investigations, Jan 17, 2018
A group of adolescents with oral piercings was studied to determine the presence of metallic part... more 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. 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. 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...