Pam2CSK4 (TLR2 agonist) induces periodontal destruction in mice

Abstract Lipoproteins are important bacterial immunostimulating molecules capable of inducing receptor activator of nuclear factor-κB (RANKL) and osteoclast formation in vitro and in vivo . Although these molecules are present in periodontopathogenic bacteria, their role in periodontitis is not known. In this study, we used Pam2CSK4 (PAM2), a synthetic molecule that mimics bacterial lipoprotein, to investigate the effects of lipoproteins on periodontitis in mice. C57BL/6 male mice were randomly divided into three experimental groups: 1) Negative control group: animals received vehicle injection; 2) Positive control group: animals received injection of Escherichia coli lipopolysaccharide (LPS); 3) PAM2 group: animals received PAM2 injection. All the injections were performed bilaterally every other day into the palatal mucosa between first and second molars. After twenty-four days, the animals were euthanized to assess alveolar bone volume (micro-CT), cellular and extracellular composition in the gingiva (stereometric analysis), and osteoclast numbers (TRAP staining). Treatment with either PAM2 or LPS induced gingival inflammation, as demonstrated by increased infiltration of inflammatory cells and enhanced angiogenesis, associated with a smaller number of fibroblasts and decreased extracellular matrix. Importantly, treatment not only with LPS but also with PAM2 resulted in a larger number of TRAP+ multinucleated osteoclasts and significant loss of alveolar bone. Collectively, our data demonstrate that PAM2 can induce gingival inflammation and bone loss in mice, broadening the avenues of investigation into the role of lipoproteins in the pathogenesis of periodontal disease.

Pam2CSK4 (TLR2 agonist) induces periodontal destruction in mice

Abstract Lipoproteins are important bacterial immunostimulating molecules capable of inducing receptor activator of nuclear factor-κB (RANKL) and osteoclast formation in vitro and in vivo . Although these molecules are present in periodontopathogenic bacteria, their role in periodontitis is not known. In this study, we used Pam2CSK4 (PAM2), a synthetic molecule that mimics bacterial lipoprotein, to investigate the effects of lipoproteins on periodontitis in mice. C57BL/6 male mice were randomly divided into three experimental groups: 1) Negative control group: animals received vehicle injection; 2) Positive control group: animals received injection of Escherichia coli lipopolysaccharide (LPS); 3) PAM2 group: animals received PAM2 injection. All the injections were performed bilaterally every other day into the palatal mucosa between first and second molars. After twenty-four days, the animals were euthanized to assess alveolar bone volume (micro-CT), cellular and extracellular composition in the gingiva (stereometric analysis), and osteoclast numbers (TRAP staining). Treatment with either PAM2 or LPS induced gingival inflammation, as demonstrated by increased infiltration of inflammatory cells and enhanced angiogenesis, associated with a smaller number of fibroblasts and decreased extracellular matrix. Importantly, treatment not only with LPS but also with PAM2 resulted in a larger number of TRAP+ multinucleated osteoclasts and significant loss of alveolar bone. Collectively, our data demonstrate that PAM2 can induce gingival inflammation and bone loss in mice, broadening the avenues of investigation into the role of lipoproteins in the pathogenesis of periodontal disease.

H2S in periodontal immune-inflammatory response and bone loss: a study in rats / Influência do H2S na resposta imunoinflamatória e perda óssea periodontal: um estudo em ratos

ABSTRACT Halitosis is highly prevalent in periodontitis and attributed mainly to the presence of volatile sulfur compounds (VSC), where hydrogen sulfide (H2S) is the chief culprit in the characteristic malodor of periodontitis and thus may play an active role in its pathogenesis. The aim of this study was to evaluate the effect of H2S in the acute, intermediate and chronic immuneinflammatory host response and alveolar bone loss in vivo by using an animal model of induced periodontal disease. Thirtysix rats were divided into 2 groups: test group (n = 18), rats exposed to H2S (NaHS H2S donor molecule) and control group (n = 18), rats treated with saline only (Ctrl). All animals had one of their lower second molars ligated to induce periodontal disease (PD). The sound contralateral molar was used as control (H). Each group was subdivided into 3 (n = 6), according to followup time (3h, 5 days and 14 days). The gingival tissue was used for mRNA expression analysis (IL1, IL6, RANKL, OPG and SOFAT) by realtime PCR and the mandibles were analyzed morphometrically. Data analysis showed that the ligature promoted alveolar bone loss, observed mainly at 14 days, both in the group exposed to H2S and in the Ctrl group. H2S administration did not result in additional bone loss. Gene expression showed a significant increase in IL1, IL6, RANKL and SOFAT only in the CtrlPD group (p<0.05). A significant downregulation in OPG expression was observed over time in the CtrlPD group (p<0.05). In conclusion, H2S had no effect on alveolar bone loss in the absence of a ligature. In the presence of a ligature, however, exposure to H2S had an immunoregulatory effect on the expression of proinflammatory and proresorptive cytokines.

RESUMO A halitose é altamente prevalente na periodontite e é atribuída principalmente à presença de compostos sulforosos voláteis (CSV), sendo o sulfeto de hidrogênio (H2S) o principal gás relacionado ao mau odor e que pode estar envolvido na patogênese da doença periodontal. O objetivo deste estudo foi avaliar o efeito agudo, intermediário e crônico do H2S na resposta imunoinflamatória e na perda óssea alveolar em ratos, com e sem doença periodontal induzida. Trinta e seis ratos foram divididos em 2 grupos: teste (n = 18), ratos expostos ao H2S (NaHS molécula doadora de H2S) e grupo controle (n = 18), ratos tratados apenas com solução salina (Ctrl). Todos os animais tiveram um dos seus segundos molares inferiores submetidos à colocação de uma ligadura para o desenvolvimento da doença periodontal (DP), em comparação com o dente contralateral saudável (H). Cada grupo foi subdividido em 3 (n = 6), de acordo com o tempo de eutanásia (3h, 5 dias e 14 dias). Os tecidos gengivais foram utilizados para a análise da expressão gênica (IL1, IL6, RANKL, OPG e SOFAT) por PCR em tempo real e as mandíbulas foram analisadas morfometricamente. Análise dos dados demonstrou que a ligadura promoveu perda óssea alveolar, observada principalmente aos 14 dias, tanto no grupo exposto ao H2S quanto no grupo Ctrl. A administração de H2S não resultou em perda óssea adicional. A expressão gênica demonstrou aumento significativo de IL1, IL6, RANKL e SOFAT apenas no grupo CtrlPD (p <0,05). Uma significativa regulação negativa na expressão de OPG foi observada ao longo do tempo no grupo CtrlPD (p <0,05). Podese concluir que o H2S não teve efeito adicional na perda óssea alveolar, na ausência de ligadura. Entretanto, na presença de ligadura, a exposição ao H2S teve um efeito imunorregulatório na expressão de citocinas próinflamatórias e próreabsortivas.

Losartan improves alveolar bone dynamics in normotensive rats but not in hypertensive rats

Abstract Hypertension is one of the main causes of premature death in the world; also, it is associated with several bone alterations. Preclinical studies have demonstrated delayed alveolar bone healing in hypertensive rats. However, losartan has been favorable for consolidation of bone grafts and reduction in active periodontitis. Therefore, losartan is suggested to be effective in bone formation stages, as well as in the synthesis of matrix proteins and mineralization. Objectives: To evaluate the alveolar bone dynamics in hypertensive rats treated with losartan by laser confocal microscopy and histological analysis. Methodology: Thirty-two rats, 16 spontaneously hypertensive rats (SHR) and 16 Wistar albinus rats, treated or not with losartan (30 mg/kg/day) were used. Calcein fluorochrome at 21 days and alizarin red fluorochrome at 49 days were injected in rats (both 20 mg/kg). The animals were submitted to euthanasia 67 days after treatment, and then the right maxilla was removed for laser confocal microscopy analysis and the left maxilla for histological analysis. Results: This study showed a greater calcium marking in normotensive animals treated with losartan in relation to the other groups. Laser confocal microscopy parameters showed higher values of bone volume formed, mineralized surface, active surface of mineralization and bone formation rate in normotensive animals treated with losartan. However, a smaller mineralized surface was observed in all hypertensive animals. Conclusion: Losartan can improve bone mineralization parameters under normal physiological conditions, but the same anabolic effect does not occur under hypertension.

Effect of acute administration of nicotine and ethanol on tooth movement in rats

Abstract The aim of this study was to evaluate the effect of acute administration of nicotine and ethanol on tooth movement in rats. Two hundred rats were divided into eight groups: S: saline; N: nicotine; E: ethanol; NE: nicotine and ethanol; SM: saline with tooth movement; NM: nicotine with tooth movement; EM: ethanol with tooth movement; and NEM: nicotine and ethanol with tooth movement. All the solutions were applied for 32, 44, or 58 days, according to the subgroup. Orthodontic movement (25 cN) was initiated 30 days after solution administration in the groups with tooth movement. The rats were euthanized 2, 14, or 28 days after initiation of tooth movement. Tooth sections were stained using picrosirius and tartrate-resistant acid phosphatase (TRAP). The data were compared by ANOVA using Tukey's HSD and Games-Howell. On day 28 of tooth movement, the NEM group had a lower percentage of type I collagen compared to the SM group (p = 0.0448), and the S group had a higher number of osteoclasts/μm2 compared to the N group (p = 0.0405). Nicotine and ethanol did not affect the tooth movement rate, regardless of induction of orthodontic movement. Nicotine influenced the number of osteoclasts by decreasing their quantity when dental movement was not induced. When nicotine was associated with ethanol, it interfered in the maturation of collagen fibers during orthodontic movement.

Fluoxetine effects on periodontogenesis: histomorphometrical and immunohistochemical analyses in rats

Abstract Reports have indicated that serotonin plays an important role in cell migration and differentiation during the organogenesis of several tissues, including the oral types. Administration of selective serotonin reuptake inhibitor (SSRI) drugs during pregnancy could affect the delivery of serotonin to embryonic tissues altering its development. Objective This study aimed to assess the effects of fluoxetine, a selective serotonin reuptake inhibitor, on the formation of the periodontal ligament during pregnancy and lactation in rat pups. Material and Methods Twelve pregnant rats of Wistar lineage were divided into four study groups. In the control group, 0.9% sodium chloride solution was administered orally, throughout the entire period of the 21 days of pregnancy (CG group) and in the CGL group, it was administrated during pregnancy and lactation (from day 1 of pregnancy to the 21st day after birth). Fluoxetine was administered orally at the dose of 20 mg/kg in a group treated during pregnancy only (FG group), and during pregnancy and lactation (FGL group). Histometrical, histochemical and immunohistochemical analysis of the maxillary first molar periodontium region of the 24 rat pups was made under light microscopy, and periodontal ligament collagen was qualitatively evaluated under a polarizing light microscope. Results The quantity of fibroblasts (p=0.006), osteoblasts (p=0.027) and cementoblasts (p=0.001) was reduced in pups from the rats that received fluoxetine during pregnancy and lactation. No alterations were seen in the collagen fibers. Conclusion These findings suggest that periodontal tissue may be sensitive to fluoxetine, and its interference in reducing periodontal cells depends on exposure time during lactation.

Effects of Coffee Intake and Intraperitoneal Caffeine on Bone Repair Process - A Histologic and Histometric Study

Studies have suggested that caffeine acts on bone promoting an increase of calcium excretion, inhibition of osteoblast proliferation and delay in tissue repair process, raising the risk of fractures, osteoporosis, periodontal disease and affecting the success of bone reconstructive procedures. The aim of this study was to analyze histomorphometrically the process of alveolar bone healing after tooth extraction in rats subjected to daily intake of boiled coffee or intraperitoneal administration of caffeine. Forty-five male rats were divided according to the treatment in Control group (C); Coffee group (CO) - treated with coffee since birth; and Caffeine (CAF) - intraperitoneal injection of aqueous solution of caffeine 1.5% (0.2 mL/100g body weight) for 30 days. When weighing between 250-300 g they were anesthetized, subjected to extraction of the maxillary right incisor, and euthanized 7, 21 and 42 days after surgery for histological assessments of bone volume and the quality of formed bone in the dental socket. The qualitative results demonstrated larger amounts of blood clot and immature bone in animals under treatment of pure caffeine compared to coffee and control. Histometric analysis revealed that coffee treatment led to a 40% drop in bone formation, and caffeine a 60% drop in comparison to control animals (ANOVA p≤0.01). It was concluded that both the daily ingestion of coffee and the intraperitoneal administration of caffeine in rats delayed the alveolar bone reparative process after tooth extraction, and this effect was more aggressive when pure caffeine was used.

Estudos têm sugerido que a cafeína age sobre o osso promovendo um aumento da excreção de cálcio, inibição da proliferação dos osteoblastos e retardo no processo de reparação tecidual, aumentando o risco de fraturas, osteoporose, doença periodontal, bem como afetando o sucesso de procedimentos de reconstrução óssea. O objetivo deste estudo foi analisar histomorfometricamente o processo de reparação óssea alveolar após extração dentária em ratos submetidos à ingestão diária de café fervido ou a administração intraperitoneal de cafeína. 45 ratos machos foram divididos de acordo com o tratamento, em controle (C); café (CO), tratados com café desde o nascimento; e cafeína (CAF), injeção intraperitoneal de solução aquosa de cafeína de 1,5 % (0,2 mL/100 g de peso corporal) durante 30 dias. Quando pesavam entre 250-300 g os animais foram anestesiados, submetidos à extração do incisivo superior direito, e sacrificados em 7, 21 e 42 dias após a cirurgia para análises histológicas quanto ao volume e à qualidade do osso formado no alvéolo dental. Os resultados qualitativos demonstraram grandes quantidades de coágulo sanguíneo e osso imaturo nos animais tratados com cafeína pura, em relação aos grupos café e controle. A avaliação histométrica mostrou que o tratamento com o café levou a uma queda na formação óssea de 40%, e com a cafeína de 60% em comparação ao grupo controle (ANOVA p≤0,01). Concluiu-se que tanto a ingestão diária de café quanto a administração intraperitoneal de cafeína em ratos retardou o processo de reparação do osso alveolar após extração dentária, e este efeito é mais agressivo quando do uso da cafeína pura.

Alveolar bone loss induced by chronic ethanol consumption from adolescence to adulthood in Wistar rats.

Though there are literature indicating the bone loss due to alcohol consumption, studies on the association between ethanol consumption and periodontal breakdown in animals are either scarce or have provided conflicting results. Here, we investigated the effects of chronic alcohol exposure from adolescence to adulthood on the alveolar bone in rats. Wistar rats were exposed to ethanol (6.5 g/kg/day) in a solution of 22.5% (w/v) or distilled water (control) by gavage from 35 days of age (adolescent) until 90 days (adulthood). Evaluation of the bone loss was performed using scanning electronic microscopy, in which the distances between the cement-enamel junction and the alveolar bone crest from the palatal side of the first molar mandibular were measured. The measurements obtained were tabulated and analyzed using Student’s t-test. Alcohol-treated group revealed greater bone loss in comparison to the control group. These findings indicate that heavy chronic alcohol exposure from adolescent to adulthood can induce alveolar bone loss in rats associated to absence of periodontitis.

Nicotine effect on bone remodeling during orthodontic tooth movement: Histological study in rats

Introduction: Nicotine is harmful to angiogenesis, osteogenesis and synthesis of collagen. Objective: The aim of this study was to investigate the effect of nicotine on bone remodeling during orthodontic movement in rats. Methods: Eighty male Wistar rats were randomly divided into three groups: Group C (control), group CM (with orthodontic movement) and group NM (nicotine with orthodontic movement) groups. The animals comprising groups C and CM received 0.9% saline solution while group NM received nicotine solution (2 mg/kg). A nickel-titanium closed-coil spring was used to induce tooth movement. The animals were euthanized and tissue specimens were processed histologically. We quantified blood vessels, Howship's lacunae and osteoclast-like cells present in the tension and compression areas of periodontal ligaments. The extent of bone formation was evaluated under polarized light to determine the percentage of immature/mature collagen. Results: We observed lower blood vessel densities in the NM group in comparison to the CM group, three (p < 0.001) and seven (p < 0.05) days after force application. Osteoclast-like cells and Howship's lacunae in the NM group presented lower levels of expression in comparison to the CM group, with significant differences on day 7 (p < 0.05 for both variables) and day 14 (p < 0.05 for osteoclast-like cells and p < 0.01 for Howship's lacunae). The percentage of immature collagen increased in the NM group in comparison to the CM group with a statistically significant difference on day 3 (p < 0.05), day 7 (p < 0.001), day 14 (p < 0.001) and day 21 (p < 0.001). Conclusions: Nicotine affects bone remodeling during orthodontic movement, reducing angiogenesis, osteoclast-like cells and Howship's lacunae, thereby delaying the collagen maturation process in developed bone matrix. .

Introdução: a nicotina apresenta efeito prejudicial sobre a angiogênese, osteogênese e síntese de colágeno. Objetivo: investigar a ação da nicotina sobre a remodelação óssea durante o movimento dentário induzido em ratos. Métodos: oitenta ratos machos Wistar foram divididos em três grupos: grupo C (sem indução de movimento dentário e sem a ação da nicotina - controle); grupo CM (indução de movimento dentário) e grupo NM (indução de movimento dentário associado à ação da nicotina). Os animais dos grupos C e CM receberam solução salina a 0,9% e os animais do grupo NM receberam nicotina (solução PA a 98% diluída em solução salina a 0,9% estéril) por via subcutânea (2mg/kg). Após a eutanásia dos animais, com 3, 7, 14 e 21 dias de uso da mola ortodôntica, os espécimes teciduais foram processados histologicamente e quantificou-se o número de vasos sanguíneos, lacunas de Howship e células osteoclásticas nos lados de tração e compressão do ligamento periodontal. A neoformação óssea foi avaliada por meio de luz polarizada, para determinar a porcentagem de colágeno maduro e imaturo. Resultados: observou-se que a quantidade de vasos sanguíneos diminuiu no grupo NM, quando comparado ao grupo CM, nos períodos de três (p < 0,001) e sete (p < 0,05) dias. Quanto às células osteoclásticas e lacunas de Howship, o grupo NM apresentou menores níveis de expressão em relação ao grupo CM, com diferença estatisticamente significativa nos períodos de 7 e 14 dias. A porcentagem de colágeno imaturo apresentou-se aumentada no grupo NM, quando comparado ao grupo CM, em todos os períodos analisados, com diferença e...

Effect of Growth Hormone in Experimental Tooth Movement

The aim of this study was to evaluate, by histological analysis, the effect of growth hormone (GH) on periodontal ligament and alveolar bone during experimental tooth movement in rats. Eighty male Wistar rats divided into control (C) and experimental (E) groups were examined after 3, 7, 14 and 21 days under controlled climate conditions. Orthodontic force (30 cN) was applied on the maxillary first molar by an orthodontic appliance. Group E received 0.1 IU/kg/day of GH and Group C received 0.5 mL/kg/day of saline. The samples were processed and evaluated under optical microscopy and polarized light microscopy. The Kruskal Wallis test was applied to compare the intergroup variables at 5% significance level. Group E presented a larger number of osteoclasts on the 3rd and 7th days and Howship lacunae on the 3 rd day, a smaller number of blood vessels and greater amount of mature collagen on the 3 rd and 7 th days than Group C (p<0.05). It was concluded that GH accelerated and intensified bone resorption and produced delay in immature collagen formation during experimental tooth movement.

O objetivo deste estudo foi avaliar histologicamente o efeito do hormônio de crescimento (HC) no ligamento periodontal e osso alveolar, durante a movimentação dentária induzida em ratos. Oitenta ratos Wistar, machos, divididos nos grupos controle e experimental, foram observados nos dias 3, 7, 14 e 21. Foi aplicada força ortodôntica (30 cN) sobre o primeiro molar superior por meio de um dispositivo ortodôntico. No grupo experimental foi administrada 0,1 UI/kg/dia de HC e, no grupo controle, 0,5 mL/kg/dia de solução salina. As amostras foram processadas e avaliadas por microscopia de luz e luz polarizada. O teste de Kruskal Wallis foi utilizado para a comparação das variáveis intergrupos. Verificou-se que o grupo experimental apresentou maior quantidade de osteoclastos nos 3° e 7° dias e de lacunas de Howship no 3° dia, menor quantidade de vasos sanguíneos e maior quantidade de colágeno maduro nos 3° e 7° dias do que no grupo controle (p<0,05). Concluiu-se que o HC acelerou e intensificou a reabsorção óssea e produziu atraso na formação de colágeno imaturo, durante o movimento ortodôntico induzido.

Evaluation of subcutaneous and alveolar implantation surgical sites in the study of the biological properties of root-end filling endodontic materials

OBJECTIVE: The aim of this study was to compare two methodologies used in the evaluation of tissue response to root-end filling materials in rats. MATERIAL AND METHODS: Forty rats were divided into 4 groups: in Groups I and II (control groups), empty polyethylene tubes were implanted in the extraction site and in the subcutaneous tissue, respectively; in Groups III and IV, polyethylene tubes filled with ProRoot MTA were implanted in the extraction site and in the subcutaneous tissue, respectively. The animals were killed 7 and 30 days after tube implantation, and the hemi-maxillas and the capsular subcutaneous tissue, both with the tubes, were removed. Specimens were processed and evaluated histomorphologicaly under light microscopy. The scores obtained were analyzed statistically by the Kruskal-Wallis test (p<0.05). RESULTS: There were no statistically significant differences between the implantation methods (p=0.78033, p=0.72039). It was observed that the 30-day groups presented a more mature healing process due to smaller number of inflammatory cells. CONCLUSIONS: The present study showed no differences in tissue responses as far as the implantation site and the studied period were concerned. Alveolar socket implantation methodology represents an interesting method in the study of the biological properties of root-end filling endodontic materials due to the opportunity to evaluate bone tissue response.

[Histologic and morphometric evaluation of the effects of bio-oss and cerasorb, on residual ridge preservation following tooth extraction in dog]

Following extraction of teeth the alveolar ridge resorbs and may result in inadequate bone volume for dental implant placement. The aim of this study was to make a histologic and morphometric analysis of the effect of using Bio-oss [a bovine derived xenograft] and Cerasorb [a beta tricalcium phosphate synthetic material] in preventing or reducing the alveolar bone resorption following tooth extraction in comparison with empty sockets as untreated control in a dog model. In this interventional animal study, 5 healthy adult dogs were used. The 2[nd] and 3[rd] mandibular premolars were extracted after reflecting a surgical flap. Following random allocation, the available sockets either served as the untreated control [n=13] or received either Bio-oss [n=10] or Cerasorb [n=10] as test groups. An alginate impression was taken before the application of materials to fabricate a stone cast to serve as an index to make morphometric measurements. The healing events were uncomplicated and six months after the surgical procedures, the dogs were sacrificed and after removing the soft tissues, another impression was taken from the mandibular hard tissues and the tissue blocks were prepared for histologic examination. Morphometric maesurments aimed to measure the changes in vertical dimentions of the buccal and lingual bony plates as well as the horizontal reduction of the ridge at the crest. The data were analyzed by ANOVA and Kruskal-Wallis test. The histologic evaluation included the examination of the quality of the harvested hone as well as the inspection for the presence of remnants of unresorbed biomaterials. The mean changes of buccal and lingual crests and mean ridge reduction were not significantly different between control and cases groups. Histologic examination revealed that in all three groups, the cortical bony plates were thinner and of lower density at the buccal side compared to the lingual side. No trace of inflammatory cell infiltration was observed in any groups. In general, the histologic appearance of the 3 types of specimens resembled to normal lamellar bone. The results of this study showed that the vertical and horizontal resorbion of alveolar ridge following the extraction were minimal at three groups even at the untreated control sites

The influence of ovariectomy, simvastatin and sodium alendronate on alveolar bone in rats

Bisphosphonates are currently used in the treatment of many diseases involving increased bone resorption such as osteoporosis. Statins have been widely used for the treatment of hypercholesterolemia and recent studies have shown that these drugs are also capable of stimulating bone formation. The purpose of this study was to evaluate the influence of an estrogen deficient state and the effects of simvastatin and sodium alendronate therapies on alveolar bone in female rats. Fifty-four rats were either ovariectomized (OVX) or sham operated. A month later, the animals began to receive a daily dose of simvastatin (SIN - 25 mg/kg), sodium alendronate (ALN - 2 mg/kg) or water (control) orally. Thirty-five days after the beginning of the treatment, the rats were sacrificed and their left hemimandibles were removed and radiographed using digital X-ray equipment. The alveolar radiographic density under the first molar was determined with gray-level scaling and the values were submitted to analysis of variance (a = 5 percent). Ovariectomized rats gained more weight (mean ± standard deviation: 20.06 ± 6.68 percent) than did the sham operated animals (12.13 ± 5.63 percent). Alveolar radiographic density values, expressed as gray levels, were lowest in the OVX-water group (183.49 ± 6.47), and differed significantly from those observed for the groups receiving alendronate (sham-ALN: 193.85 ± 3.81; OVX-ALN: 196.06 ± 5.11) and from those of the sham-water group (193.66 ± 4.36). Other comparisons between groups did not show significant differences. It was concluded that the ovariectomy reduced alveolar bone density and that alendronate was efficient for the treatment of this condition.

Os bisfosfonatos são empregados atualmente para o tratamento de várias doenças caracterizadas pelo aumento da reabsorção óssea, como a osteoporose. As estatinas são amplamente utilizadas para redução de níveis elevados de colesterol e estudos recentes têm revelado sua ação anabólica no osso. O objetivo deste trabalho foi avaliar a influência da deficiência estrogênica e dos tratamentos com sinvastatina ou alendronato sódico no osso alveolar em ratas. Cinqüenta e quatro ratas sofreram ovariectomia (OVX) ou cirurgia simulada ("sham"). Um mês após, os animais passaram a receber diariamente, via oral, 25 mg/kg de sinvastatina (SIN), 2 mg/kg de alendronato (ALN) ou água (controle). Trinta e cinco dias depois do início do tratamento os animais foram sacrificados, as hemimandíbulas esquerdas removidas e radiografadas em aparelho de raios X digital. Foi calculada a densidade radiográfica em tons de cinza da área de osso alveolar sob o primeiro molar mandibular e os valores foram submetidos a ANOVA, ao nível de 5 por cento. Ratas ovariectomizadas ganharam mais peso (média ± desvio-padrão: 20,06 ± 6,68 por cento) que as demais (12,13 ± 5,63 por cento). Os valores de densidade radiográfica, em tons de cinza, foram menores nos animais do grupo OVX-água (183,49 ± 6,47), significantemente diferentes daqueles observados nos grupos que receberam alendronato ("sham"-ALN: 193,85 ± 3,81; OVX-ALN: 196,06 ± 5,11) e no grupo "sham"-água (193,66 ± 4,36). Outras comparações entre grupos não revelaram diferenças estatísticas. Concluiu-se que a ovariectomia reduziu a densidade óssea alveolar e que o tratamento com alendronato sódico foi eficiente para o tratamento desta situação.

Periodontal & systemic bone changes in rats with experimental lathyrism.

BACKGROUND & OBJECTIVE: It is not clear how lathyrism affects the systemic bone metabolism. We therefore undertook a study to observe periodontal and systemic bone changes by performing radiological, metabolic, and bone densitometric evaluations in rats with experimental lathyrism. METHODS: A total of 30 rats were used. Experimental lathyrism was induced by once daily subcutaneous administration of beta-aminopropionitrile (beta-APN), at a dose of 5 mg beta-APN/0.4 ml per 100 g of body weight for 40 days. After 40 days, vertebral bone mineral density was analyzed by means of dual energy X-ray absorbtiometry in both groups. Blood was drawn by cardiac puncture and the animals were decapitated. Serum calcium levels were measured. Right mandibles were removed and radiographs were obtained. Alveolar bone level was determined in the radiographs. RESULTS: In all lathyritic rats, alveolar bone level was pathologically decreased with visible resorption. Vertebral bone mineral density values of lathyritic rats did not differ significantly from those of the control group. Compared to controls, there was a statistically significant decrease in serum calcium levels in the lathyritic group (P<0.001). INTERPRETATION & CONCLUSION: Significant alveolar bone resorption without alterations in vertebral bone mineral density indicated that lathyrogen administration for 40 days presumably has not caused systemic demineralization. This model could be used for studying the role of local and systemic agents on periodontal alveolar bone resorption.

The effect of dexamethasone in the pathogenesis of ligature-induced periodontal disease in Wistar rats

O objetivo deste estudo foi avaliar o papel do uso sistêmico da dexametasona na patogênese da perda óssea alveolar induzida em ratos. Em 26 ratos Wistar fêmeas, foram colocadas ligaduras em torno do seu segundo molar superior, servindo o lado contralateral como controle intragrupo. Foram formados dois grupos. O grupo teste recebeu 0,5 mg/kg de dexametasona subcutaneamente a cada três dias durante um período de 30 dias. O grupo controle recebeu a mesma quantidade de solução salina. Após 30 dias, os animais foram sacrificados e suas maxilas removidas. Para o preparo das peças foi usado hipoclorito de sódio e, para corar a junção cemento-esmalte, foi usado azul de metileno. A análise morfométrica da perda óssea alveolar foi realizada por fotografias digitais padronizadas, e a distância entre a junção cemento-esmalte e a crista óssea alveolar foi medida pelo programa ImageTool 3.0. A calibração intra-examinador revelou um coeficiente de Pearson de 0,99. A análise estatística foi realizada pelo teste t pareado ou teste t para amostras independentes, conforme apropriado (a = 0,05). A dexametasona aumentou a média de perda óssea alveolar na periodontite induzida por ligadura em relação ao grupo controle (0,77 e 0,61 por vestibular e 0,65 e 0,56 por palatino, respectivamente). Não foram observadas diferenças significativas intergrupos nos dentes sem ligadura. No modelo animal usado neste estudo, a dexametasona aumentou a progressão de perda óssea alveolar induzida por ligadura.

Histologic study of use of microfibrillar collagen hemostat in rat dental sockets

The aim of this paper was to evaluate if the placement of microfibrillar collagen hemostat (MCH) into a dental socket interfered with healing. General anesthesia was administered to 30 adult male Albinus Wistar rats and the maxillary right central incisor was extracted. In the control group after each tooth was extracted, the socket was sutured. In the MCH group after each tooth was extracted, MCH was placed into the socket before suturing. Postoperatively, 5 animals were sacrificed from each group at 7, 21 and 28 days. The right maxilla was removed from each animal and histologic slides were stained with Masson's trichromic and hematoxylin and eosin. Quantitative and qualitative analyses were done. The percentage of bone area in the dental socket was quantified using the Image Lab 98 image analysis system. The bone area formation for the control and MCH groups was: 8.1 percent and 3.3 percent at 7 days, 34.4 percent and 33 percent at 21 days and 41 percent and 41.3 percent at 28 days, respectively. We concluded that MCH interferes with the beginning of dental socket healing but does not interfere with the final healing of the dental socket

Bisfosfonato e movimentaçäo dentária induzida: avaliaçäo microscópica de seus efeitos / Biophosphonates and induced tooth movement: microscopical evaluation of its effects

Os biofosfonatos säo eficientes bloqueadores das reabsorçöes e, por isso, säo utilizados no controle das doenças metabólicas ósseas. Os mecanismos pelos quais essas drogas interferem nos processos de reabsorçäo ainda näo estäo totalmente esclarecidos, mas incluem a inibiçäo da funçäo e a alteraçäo da morfologia dos clastos e precursores, além da atuaçäo como citotóxicos sobre os macrófagos e os osteoblastos. Num modelo experimental de movimentaçäo dentária induzida, procurou-se verificar, microscopicamente, a influência do clodronato sobre a morfologia do osso alveolar, do ligamento periodontal e do cemento dos primeiros molares superiores de 45 ratas com 90 dias de vida, nos tempos experimentais de 24 horas, 3, 5, 7, 10 e 21 dias de movimento. Os resultados microscópicos revelaram que a administraçäo do clodronato näo interferiu em nenhuma das situaçöes referidas, inclusive durante o movimento dentário induzido, nas diversas fases analisadas. A presença localizada mais intensa de infiltrado inflamatório crônico sugere uma influência dos bisfosfonatos nos processos inflamatórios

Efeito da ciclosporina sobre a cronologia do processo de reparo em feridas de extraçäo dental: estudo histológico em ratos / The colateral effects of cyclosporin on the healing of extraction wounds: the histologic study in rats

Alguns trabalhos têm enfatizado a importância do cirurgiäo-dentista no auxílio da prevençäo, controle e tratamento dos efeitos colaterais da ciclosporina que possam manifestar na cavidade bucal. Ainda que a hiperplasia gengival e a parestesia facial correspondam aos efeitos colaterais mais freqüêntes na cavidade bucal, outras alteraçöes podem ocorrer, particularmente após as exodontias. No presente trabalho foram estudados, através de cortes histológicos, os efeitos da ciclosporina sobre o processo de reparo em feridas de extraçäo dental em ratos. Para tanto, foram empregados 50 ratos que foram divididos em dois grupos de 25: Grupo I (controle) e Grupo II (trabalho). No primeiro grupo, após a extraçäo do incisivo superior direito, cada animal recebeu 0,5ml de soro fisiológico em injeçäo subcutânea diária. No Grupo II, após a exodontia, cada animal recebeu diariamente 5mg de ciclosporina por via subcutânea. Em número de cinco ratos para cada grupo os animais foram sacrificados aos 3, 9, 15, 21 e 28 dias após o ato operatório. As peças obtidas, após processamento laboratorial de rotina, foram incluídas em parafina para permitir a microtomia. Os cortes obtidos foram corados em hematoxilina e eosina para estudo histomorfológico. Os resultados obtidos permitem concluir que a ciclosporina retarda a cronologia do processo de reparo em feridas de extraçäo dental

Influência do alveoliten no processo de reparo alveolar: em feridas de extração dental infectadas. Estudo histológico em ratos / The influence of \"Alveoliten\" on the alveolar repair: histological study in rat

Os autores estudaram a influência do "Alveoliten" em alvéolos acometidos por alveolite provocada experimentalmente em ratos. Foi possível concluir que o tratamento local com limpeza cirúrgica e colocação do medicamento, acelera o reparo alveolar quando comparado ao grupo experimental, da alveolite e sem tratamento

Processo de reparo alveolar em ratos tratados com aguardente de cana: estudo histológico / Dental socket healing process in rats treated with sugar cane brandy (pinga): histological study

Os autores estudaram o efeito da ingestäo crônica de álcool no processo de reparo de incisivos superiores de ratos. Pela análise histológica concluíram que a administraçäo crônica de etanol (50º GL) retarda a cronologia do processo de reparo alvelar quando comparado com grupo controle