ABSTRACT OBJECTIVE: The present study evaluated morphometrically bone loss percentages in experimental periodontitis in rats, comparing different locations (lingual mandible, palatal maxilla and buccal maxilla) and two evaluation methods (distance and area methods). MATERIAL AND METHODS: Ligatures were placed around the maxillary right second molar and around the mandibular right first molar in 14 female Wistar rats. The contralateral molars served as intragroup controls. After 4 weeks, the rats were sacrificed and their mandible and maxilla were removed. The specimens were dissected and stained with methylene blue dye. Bone loss was evaluated by two different methods on the surfaces of the defleshed jaw. In the first method, the distance from the cementoenamel junction (CEJ) to the alveolar bone crest was measured in the roots of teeth associated with ligature. In the second method, the area of bone loss was determined using the alveolar tissue bone, CEJ and the proximal region of roots associated with the ligature as reference. The data were converted to bone loss percentages caused by ligature: (ligated - unligated) x 100/ligated. RESULTS: When comparing the distance and area methods, no statistically significant difference was observed (p>0.05). Both methodologies indicated that the maxilla presented greater bone loss than the mandible and it was more accentuated on the buccal side than on the palatal side (p<0.05). CONCLUSIONS: The findings of this study show that both the area and the distance methods can be used to evaluate bone loss caused by ligature placement in rats, and suggest applying the morphometric methodology to the maxilla on the buccal side.

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%. Ratas ovariectomizadas ganharam mais peso (média ± desvio-padrão: 20,06 ± 6,68%) que as demais (12,13 ± 5,63%). 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.

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%). Ovariectomized rats gained more weight (mean ± standard deviation: 20.06 ± 6.68%) than did the sham operated animals (12.13 ± 5.63%). 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.

OBJETIVO: O propósito deste estudo foi avaliar o efeito do consumo de álcool sobre o suporte ósseo periodontal (SOP) em periodontite induzida por ligaduras em ratos. MATERIAIS E MÉTODOS: Sessenta e três ratos machos foram divididos em sete grupos: G1 (controle); G2 (álcool a 10%); G3 (controle nutricional de G2); G4 (álcool a 20%); G5 (controle nutricional de G4); G6 (álcool a 30%); G7 (controle nutricional de G6). Os grupos G3, G5 e G7 receberam dietas controladas com a mesma quantidade de calorias consumidas por G2, G4 e G6, respectivamente, com o etanol substituído por sacarose. Após anestesia foram instaladas ligaduras no primeiro molar inferior direito, permanecendo o dente contralateral sem ligadura. Após oito semanas, os ratos foram sacrificados e as mandíbulas radiografadas para medição do SOP na proximal distal. RESULTADOS: A análise intragrupo mostrou que a presença da ligadura foi capaz de induzir periodontite (p<0,05). Os grupos sem ligadura não demonstraram diferenças significativas (p=0,1969) no SOP. Contudo, nos grupos com ligadura os ratos que receberam álcool (G2:48,71%±3,88; G4:47,66%±2,54; G6:47,32%±3,24) e o controle nutricional associado a alta concentração de etanol (G7:47,40%±3,24) apresentaram percentual de SOP estatisticamente inferior aos outros grupos (G1:52,40%±2,75; G3:52,83%±2,41; G5:50,85%±4,14). CONCLUSÕES: Os resultados demonstraram que o consumo de álcool em ratos pode resultar em efeito direto na perda óssea alveolar, aumentando o desenvolvimento da periodontite. Além disso, sugere-se que o consumo calórico pesado de etanol também pode apresentar efeito indireto nos tecidos periodontais, como conseqüência da má nutrição.

OBJECTIVE: The aim of this study was to evaluate the effect of the alcohol consumption on the periodontal bone support (PBS) in experimental periodontitis in rats. MATERIALS AND METHODS: Sixty-three male rats were divided into seven groups: G1 (control); G2 (10% ethanol); G3 (nutritional control of G2); G4 (20% ethanol); G5 (nutritional control of G4); G6 (30% ethanol) and G7 (nutritional control of G6). The groups G3, G5 and G7 received controlled diets with equivalent caloric amounts to those consumed in G2, G4 and G6 respectively, with the ethanol replaced by sucrose. After anesthesia, ligatures were installed around the mandibular first molar, leaving the contralateral teeth unligated. After 8 weeks, the rats were killed and their mandibles were radiographed to measure the percentage of PBS on the distal aspect. RESULTS: The intragroup analyses showed that presence of ligatures induced periodontitis (p<0.05). Unligated groups did not show significant differences among the percentages of PBS (p=0.1969). However, in ligated groups the rats that received alcohol (G2:48.71%±3.88; G4:47.66%±2.54; G6:47.32%±3.24) and the nutritional control group associated with a high concentration of ethanol (G7:47.40%±3.24) presented a significantly lower percentage of PBS than the other groups (G1:52.40%±2.75; G3:52.83%±2.41; G5:50.85%±4.14). CONCLUSIONS: These results demonstrated that alcohol consumption in rats may result in a direct effect on alveolar bone loss and increased development of periodontitis. In addition, they suggest that heavy caloric consumption of ethanol may also present an indirect effect on periodontal tissue as a consequence of malnutrition.

O objetivo deste trabalho foi avaliar a influência da ausência de hormônios ovarianos induzida por ovariectomia como fator de risco para a doença periodontal em ratas. Quarenta ratas com idade de 90 dias foram submetidas a ovariectomia (OVX; n=20) ou cirurgia simulada (sham) (SHAM; n=20). Após 30 dias, ligaduras de algodão foram colocadas ao redor dos segundos molares superiores de 10 animais OVX e 10 animais SHAM. Cinco semanas após, todos os animais foram sacrificados. As ratas foram pesadas antes de todos os procedimentos cirúrgicos. As hemimaxilas esquerdas foram removidas e determinaram-se a porcentagem de suporte ósseo, através de radiografias, e a área de perda óssea alveolar, macroscopicamente, após maceração, com auxílio de programa computacional, além do grau de envolvimento de furca. Os dados foram submetidos à análise estatística por meio de ANOVA com nível de significância de 5%. No período avaliado, as ratas ovariectomizadas apresentaram maior ganho de peso que aquelas submetidas à cirurgia simulada (sham) (p<0.001). As ratas em que foi induzida periodontite apresentaram suporte ósseo estatisticamente menor e maior perda óssea alveolar e envolvimento de furca que as demais (p<0.001). Porém, não foram encontradas diferenças significantes entre os animais ovariectomizados e não-ovariectomizados (p>0.05). Com bases nos achados deste estudo, a deficiência de hormônios ovarianos não pôde ser considerada como fator de risco para a doença periodontal.

The purpose of this study was to evaluate the impact of ovariectomy-induced estrogen deficiency as a risk factor of periodontal disease in rats. Forty 90-day old female rats were either ovariectomized (OVX; n=20) or sham operated (SHAM; n=20). After 30 days, periodontitis was induced by placement of a cotton ligature around the upper second molars of 10 OVX and 10 SHAM animals. All animals were sacrificed 5 weeks later. Body weight was assessed before all surgical procedures. The left hemimaxillas were removed and the percentage of periodontal bone support was determined radiographically and buccal alveolar bone loss was determined macroscopically using an image-analysis software. Furcation involvement was also evaluated. Data were analyzed statistically by ANOVA at 5% significance level. Within the evaluated period, the ovariectomized rats gained more weight than the sham-operated animals (p<0.001). The animals in which periodontitis was induced had less bone support, greater alveolar bone loss and furcation involvement than those without ligature (p<0.001). However, there was no difference between ovariectomized and sham-operated animals (p>0.05). Based on the findings of this study, estrogen deficiency could not be considered as a risk factor for periodontal disease.