Alveolar bone dynamics in osteoporotic rats treated with raloxifene or alendronate: confocal microscopy analysis.

In this study, the characteristics of the alveolar bone of rats with induced osteoporosis were examined. Thirty-two rats were divided into four groups according to the induction of osteoporosis and drugs administered: OG, osteoporotic rats without treatment (negative control); SG, rats which underwent sham surgery ovariectomy (SHAM); alendronate (AG), osteoporotic rats treated with alendronate; and RG, osteoporotic rats treated with raloxifene (RG). On the 8th day after ovariectomy and SHAM surgeries, drug therapy was started with AG or RG. On the 52nd day, 20 mg/kg calcein was administered to all of the rats, and on the 80th day, 20 mg/kg alizarin red was administered. Euthanasia was performed on the 98th day. The bone area marked by fluorochromes was calculated and data were subjected to two-way ANOVA test and Tukey's post-hoc test (p < 0.05). The comparison of the induced osteoporosis groups showed no statistically significant differences in bone turnover only between RG and SG (p = 0.074) and AG and OG (p = 0.138). All other comparisons showed significant differences (p < 0.001). The largest bone turnover was observed in RG and SG groups. RG was the medication that improved the dynamics of the alveolar bone of rats with induced osteoporosis, resembling that of healthy rats.

Hypertension modifies OPG, RANK, and RANKL expression during the dental socket bone healing process in spontaneously hypertensive rats.

OBJECTIVE: The aim of this study was to evaluate the dental socket bone healing process by histomorphometric and immunohistochemical analysis of osteoprotegerin (OPG), receptor activator of nuclear factor-κß (RANK), and receptor activator of nuclear factor-κß ligand (RANKL) proteins in spontaneously hypertensive rats (SHR). MATERIALS AND METHODS: Under general anesthesia, 25 Wistar rats and 25 SHRs underwent upper right incisor extraction. Rats were euthanized after 7, 14, 21, 28, or 42 days of dental extractions. Histomorphometric and immunohistochemical analyses of OPG, RANK, and RANKL proteins were performed. RESULTS: Histomorphometric results showed decreased bone healing and reduced bone trabecular thickness in SHRs. Immunohistochemical reactions showed intense RANKL and RANK immunolabeling at 14 and 28 postoperative days and mild OPG immunolabeling at 7, 14, and 21 days after surgery in SHRs. CONCLUSION: The results of this study show that RANK, RANKL, and OPG immunolabeling was altered in SHRs, and these results are associated with bone healing delay and decreased trabecular thickness in SHRs. CLINICAL RELEVANCE: Hypertension alters the expression of RANK, RANKL, and OPG and delays the socket bone healing process. These alterations could influence some dental procedures such as orthodontic treatment and implant placement.

Block bone graft fixation (onlay): a modification of the surgical technique.

Several reconstructive methods of the alveolar ridge have been reported to make possible future rehabilitations with implants. Many of these methods come from studies done in animals, mainly rats. With this clinical practice based on scientific evidence, any experimental procedure that can be undertaken in real life is fundamental. Thus, any research that emulates as closely as possible those techniques used in humans are important. This study describes the modification of the technique for block bone graft fixation (onlay) in rats using the "lag screw"-type technique, normally used in clinical procedures for grafts in humans. The conclusion was that the execution of the described procedures minimizes interference of blood flow in the area because of the maintenance of the muscle insertion in the buckle aspect of the most anterior region of the mandible, providing better stability to the graft and better contact interface of the graft and receptor bed.

Evaluation of the presence of VEGF, BMP2 and CBFA1 proteins in autogenous bone graft: histometric and immunohistochemical analysis.

AIMS: The purpose of this study was to evaluate the expression of proteins that participate in the osteoinduction stage (VEGF, BMP2 and CBFA1) of the process of bone regeneration of defects created in rat calvariae and filled with autogenous bone block grafts. MATERIALS AND METHODS: 10 adult male rats (Rattus norvegicus albinus, Wistar) were used, who received two bone defects measuring 5 mm each in the calvariae. The bone defects constituted two experimental groups (n = 10): Control Group (CONT) (defects filled with a coagulum); Graft Group (GR) (defects filled with autogenous bone removed from the contralateral defect). The animals were submitted to euthanasia at 7 and 30 days post-operatively. RESULTS: Quantitative analysis demonstrated significantly greater bone formation in Group GR, but the presence of the studied proteins was significantly greater in the CONT Group in both time intervals of observation. CONCLUSION: It was not possible in this study in cortical bone block groups to detect the osteoinductive proteins in a significant amount during the repair process.

Osteoconductive properties of ß-tricalcium phosphate matrix, polylactic and polyglycolic acid gel, and calcium phosphate cement in bone defects.

Extensive bone defects in maxillofacial region can be corrected with autogenous grafts; otherwise, the disadvantages of the therapeutics modality take the research for new bone substitutes. The aim of the study was to evaluate and compare the osteoconductive properties of 3 commercial available biomaterials. A total of 30 calvarial defects (5-mm diameter) were randomly divided into 5 treatment groups, with a total of 6 defects per treatment group (n = 6). The treatment groups were as follows: 500 to 1000 µm ß-tricalcium phosphate (ß-TCP), polylactic and polyglycolic acid (PL/PG) gel, calcium phosphate cement, untreated control, and autograft control. The evaluations were based on histomorphometric analysis at 60 postoperative days. The results have shown that ß-TCP and autograft control supported bone formation at 60 postoperative days. ß-Tricalcium phosphate showed the highest amount of mineralized area per total area and statistically significant compared with PL/PG, calcium phosphate cement, and untreated control groups. The PL/PG gel does not have osteoconductive properties and performed similar to empty control. Calcium phosphate cement showed higher number of multinucleated giant cells around the sites of the biomaterial and showed newly formed bone only at the edges of the biomaterial, without bone formation within the biomaterial. The findings presented herein indicate that bone formation reached a maximum level when rat calvarial defects were filled with ß-TCP at 60 postoperative days. Further studies should be conducted with ß-TCP to understand the potential of this biomaterial in bone regeneration.

Influence of low-level laser therapy on wound healing in nicotine-treated animals.

Low-level laser therapy (LLLT) has been shown to have several biological effects that favor the healing process, and nicotine has been shown to delay the healing process. In this study we investigated the healing of open wounds created on the back of rats treated with nicotine with or without LLLT. Of 115 animals, 59 received subcutaneous injections of saline solution, and the others received subcutaneous injections of nicotine (3 mg/kg body weight), twice a day throughout the study period. After 30 days, skin wounds were created on the back of the animals. The animals receiving saline injections were divided into two groups: group 1 (G1, n = 29), in which the wounds were left untreated, and group 2 (G2, n = 30), in which the wounds were treated with LLLT (GaAlAs, 660 nm, 30 mW, 5.57 J/cm(2) per point, 0.39 J, 13 s per point, 0.42 W/cm(2)). The animals receiving nicotine injections were also divided into two groups: group 3 (G3, n = 29), in which the wounds were left untreated, and group 4 (G4, n = 27), in which the wounds were treated with LLLT. The animals were killed 3, 7 or 14 days after surgery. Wound healing was evaluated histologically both qualitatively and semiquantitatively. Wounds of G2 showed a delay in epithelial migration and connective tissue organization compared to those of G1. Wounds of G2 showed faster healing than those of G1; similarly, wounds of G4 showed more advanced healing than those of G3. LLLT acted as a biostimulatory coadjuvant agent balancing the undesirable effects of nicotine on wound tissue healing.

Raloxifene therapy inhibits osteoclastogenesis during the alveolar healing process in rats.

OBJECTIVE: To investigate the expression of OPG, RANKL and TRAP during alveolar healing process (7, 14, 21, 28 and 42 postoperative days) in ovariectomized rats treated with raloxifene or with oestrogen replacement therapy, using immunohistochemistry reaction approach. MATERIALS AND METHODS: Wistar female rats (10 weeks age) were submitted to ovariectomy surgery (OVX) or sham surgery. The female rats were divided in four groups: (1) sham; (2) OVX/O (ovariectomy and oil); (3) OVX/E2 (ovariectomy and oestrogen replacement); (4) OVX/RLX (ovariectomy and raloxifene therapy). RESULTS: It was observed high amount of OPG immunolabelling with predominance at 14 and 21 postoperative days on sham and OVX/RLX groups, respectively. At 7 postoperative days, there was no difference between the groups for TRAP protein. Otherwise, to the other periods, it was observed greater expression of TRAP and RANKL protein on OVX/O group compared to sham, OVX/E2 and OVX/RLX groups. It was also observed a discrete TRAP immunolabelling at 28 and 42 postoperative days on OVX/RLX group. CONCLUSIONS: Oestrogen deficiency induces osteoclastogenesis in the alveolar healing process. Quantitative changes in the osteoclastic activity could be prevented through the raloxifene therapy.

The effect of BMP-2 on the osteoconductive properties of ß-tricalcium phosphate in rat calvaria defects.

Bone formation in critical-sized calvaria defects is strongly dependent on the osteoconductive properties of grafts. It remains a matter of controversy whether biomaterials can replace autografts and whether the supplementation of biomaterials with Bone Morphogenetic Proteins (BMPs) is necessary to enhance bone formation. We examined rat calvaria critical-sized defects (5-mm-diameter) treated with ß-tricalcium phosphate (TCP; Cerasorb® M), polylactic and polyglycolic acid gel (PLA/PGA; Fisiograft®) and calcium phosphate cement (CPC; Norian® CRS®), either alone or in the presence of 5 µg of BMP-2 after 45 days. Autografts and untreated defects served as controls. Bone formation was evaluated based on µCT analysis, histomorphometric analysis and fluorescence analysis. We report that TCP supported bone formation more efficiently than did autografts. Bone formation in the presence of TCP alone reached a maximal level, as BMP-2 supplementation failed to enhance bone formation. By contrast, no significant difference in bone formation was observed when PLA/PGA and CPC were compared to autografts. Moreover, the presence of BMP-2 did not substantially change the osteoconductive properties of PLA/PGA or CPC. We conclude that the osteoconductive properties of TCP are superior to those of autografts and that TCP does not require BMP-2 supplementation. Our findings also show that the decreased osteoconductive properties of PLA/PGA and CPC cannot be overcome by BMP-2 supplementation in rat calvaria defects.

Effect of low-level laser therapy on the healing process after tooth replantation: a histomorphometrical and immunohistochemical analysis.

Success of tooth replantation is limited because part of the replanted tooth is lost because of progressive root resorption. This study used histomorphometry and immunohistochemistry to evaluate the effect of low-level laser therapy (LLLT) on the healing process of rat teeth replanted after different extra-oral periods, simulating immediate and delayed replantation. Sixty Wistar rats (Rattus norvegicus albinus) had their maxillary right incisors extracted and randomly assigned to six groups (n = 10): C4, C30 and C45, in which the teeth were replanted 4 min (immediate), 30 min (delayed) and 45 min (delayed) after extraction, respectively, and L4, L30 and L45, in which the teeth were replanted after the same extra-alveolar times, but the root surfaces and the alveolar wounds were irradiated with a gallium-aluminum-arsenate (GaAlAs) diode laser before replantation. The animals were sacrificed after 60 days. The anatomic pieces containing the replanted teeth were obtained and processed for either histomorphometrical analysis under optical microscopy or immunohistochemical expression of receptor activator of nuclear factor Kappa-B (RANK), and its ligand (RANKL), osteoprotegerin (OPG) and tartrate-resistant acid phosphatase (TRAP) proteins. Areas of external replacement and inflammatory root resorption were observed in all groups, without statistically significant differences (P > 0.05). Ankylosis was more frequent in L30 than in C30 (P < 0.05). RANKL immunostaining predominated over RANK and OPG immunostaining in both groups with immediate tooth replantation (P < 0.05). For the 45-min extra-alveolar time, however, there was greater evidence of RANK immunostaining compared to RANKL for both control and laser-treated groups (P < 0.05). Positive TRAP immunostaining predominated in L4 and L30 (P < 0.05). In conclusion, under the tested conditions, the treatment of the root surface and the alveolar wound with LLLT did not improve the healing process after immediate and delayed tooth replantation in rats.

Bone regeneration in surgically created defects filled with autogenous bone: an epifluorescence microscopy analysis in rats.

UNLABELLED: Although the search for the ideal bone substitute has been the focus of a large number of studies, autogenous bone is still the gold standard for the filling of defects caused by pathologies and traumas, and mainly, for alveolar ridge reconstruction, allowing the titanium implants installation. OBJECTIVES: The aim of this study was to evaluate the dynamics of autogenous bone graft incorporation process to surgically created defects in rat calvaria, using epifluorescence microscopy. MATERIAL AND METHODS: Five adult male rats weighing 200-300 g were used. The animals received two 5-mm-diameter bone defects bilaterally in each parietal bone with a trephine bur under general anesthesia. Two groups of defects were formed: a control group (n=5), in which the defects were filled with blood clot, and a graft group (n=5), in which the defects were filled with autogenous bone block, removed from the contralateral defect. The fluorochromes calcein and alizarin were applied at the 7th and 30th postoperative days, respectively. The animals were killed at 35 days. RESULTS: The mineralization process was more intense in the graft group (32.09%) and occurred mainly between 7 and 30 days, the period labeled by calcein (24.66%). CONCLUSIONS: The fluorochromes showed to be appropriate to label mineralization areas. The interfacial areas between fluorochrome labels are important sources of information about the bone regeneration dynamics.

Action of nicotine and ovariectomy on bone regeneration after tooth extraction in rats.

PURPOSE: The purpose of this study was to evaluate the effects of nicotine and ovariectomy on alveolar bone regeneration after exodontias in rats. MATERIALS AND METHODS: For 30 days, sham ovariectomized (OVX)/NaCl, sham OVX/nicotine, OVX/NaCl, and OVX/nicotine animals were given 2 daily injections of saline or hemisulfate of nicotine. After this period, exodontic procedures were carried out and treatment continued up to the time of euthanasia on days 7 and 14 when the alveoli were removed for further analyses. RESULTS: The data confirmed that nicotine significantly delays the alveolar regeneration process after dental extraction in rats and showed that the association of nicotine with ovariectomy exacerbates these results. CONCLUSION: These results indicate that nicotine potentiated the effect of estrogen deficiency on bone regeneration induced by ovariectomy.

Bone regeneration in surgically created defects filled with autogenous bone: an epifluorescence microscopy analysis in rats

Although the search for the ideal bone substitute has been the focus of a large number of studies, autogenous bone is still the gold standard for the filling of defects caused by pathologies and traumas, and mainly, for alveolar ridge reconstruction, allowing the titanium implants installation. OBJECTIVES: The aim of this study was to evaluate the dynamics of autogenous bone graft incorporation process to surgically created defects in rat calvaria, using epifluorescence microscopy. MATERIAL AND METHODS: Five adult male rats weighing 200-300 g were used. The animals received two 5-mm-diameter bone defects bilaterally in each parietal bone with a trephine bur under general anesthesia. Two groups of defects were formed: a control group (n=5), in which the defects were filled with blood clot, and a graft group (n=5), in which the defects were filled with autogenous bone block, removed from the contralateral defect. The fluorochromes calcein and alizarin were applied at the 7th and 30th postoperative days, respectively. The animals were killed at 35 days. RESULTS: The mineralization process was more intense in the graft group (32.09 percent) and occurred mainly between 7 and 30 days, the period labeled by calcein (24.66 percent). CONCLUSIONS: The fluorochromes showed to be appropriate to label mineralization areas. The interfacial areas between fluorochrome labels are important sources of information about the bone regeneration dynamics.

Efeito do envelhecimento e do estresse crônico sobre a reação do tecido conjuntivo subcutâneo: estudo histológico em ratos / Effect of aging and chronic stress on the reaction of subcutaneous connective tissue: histological study in rats

As funções fisiológicas sofrem um retardo gradual que se inicia por volta de 25-30 anos e se estende até a morte. Além disso, esta alteração afeta mais gravemente as atividades mais complexas e as respostas mais intrincadas às tensões ou estresse. O propósito deste trabalho foi estudar histologicamente em ratos idosos o efeito do estresse crônico sobre a reação do tecido conjuntivo subcutâneo. Para tanto, 60 ratos, divididos em quatro grupos (GI (controle), GII (estressado), GIII (idoso) e GIV (Idoso/Estressado) receberam implante subcutâneo, bilateral e dorsal, de tubos de polietileno contendo soro fisiológico. Em grupos de cinco, os animais foram sacrificados aos 7,14 e 28 dias pós-operatórios. Os resultados obtidos permitiram observar reação inflamatória mais intensa e organização do tecido conjuntivo mais tardia nos animais idosos submetidos ao estresse

Physiological functions undergo a gradual retardation that begins around 25-30 years and extends to the death. Moreover, this change affects most severely the activities more complex and more intricate responses to tensions or stress. The purpose of this study was to evaluate histologically in aged rats the effect of chronic stress on the reaction of subcutaneous connective tissue. The purpose of this study was to evaluate histologically in aged rats the effect of chronic stress on the reaction of subcutaneous connective tissue. For this purpose, 60 rats were divided into four groups (GI (control), GII (stressed), GIII (elderly) and GIV (aged / stressed) received dorsal subcutaneous implants of polyethylene tubes containing saline solution. In groups of four animals were sacrificed at 7,14 and 28 days postoperatively. The results allowed to observe more intense inflammatory reaction and tissue organization later in the aged animals subjected to stress

Efeito do estresse crônico e benzodiazepínicos no reparo ósseo: estudo histológico em ratos / Effect of chronic stress and benzodiazepines on bone repair: histologic study in rats

Aceita-se o estresse como um fator ambiental capaz de predispor o indivíduo à depressão. Os benzodiazepínicos têm sido prescritos como drogas eficazes nessas situações. O propósito deste trabalho foi estudar histologicamente o efeito do estresse crônico e drogas benzodiazepínicas sobre o reparo ósseo. Cavidades ósseas foram criadas em ambas as tíbias de 40 ratos machos, divididos em 2 grupos: Controle e Tratado. Neste, o estímulo estressor foi aplicado nos 40 dias pré-operatórios e em todos os dias pós-operatórios até o sacrifício, pela manhã por 2 horas, por meio da imobilização por contenção. Esses animais também receberam benzodiazepínico do grupo Diazepam, diariamente, na concentração de 5mg/Kg/peso corporal nos 15 dias pré-operatórios. Em grupos de cinco, os animais foram sacrificados aos 7, 14, 30 e 60 dias pós-operatórios. Aos 7 dias pós-operatórios, enquanto o grupo controle exibia tecido conjuntivo rico em fibroblastos, o grupo tratado mostrava tecido conjuntivo neoformado, com escassos fibroblastos e vasos capilares ao lado de linfócitos e macrófagos. Aos 14 dias pós-operatórios, o Grupo Controle exibiu trabeculado ósseo neoformado enquanto o Grupo Tratado evoluiu para trabéculas ósseas delgadas, com numerosos osteoblastos em suas bordas. Aos 30 dias pós-operatórios a reparação óssea está completa em ambos os grupos. Aos 60 dias pós-operatórios as características observadas nos grupos controle e tratado são semelhantes ao período anterior, porém com osteogênese mais avançada

Stress is an environmental factor that may predispose individuals to depression. Benzodiazepines have been prescribed as effective drugs in these situations. The purpose of this study was histological evaluate of the effect of chronic stress and benzodiazepine drugs on bone healing. Bone cavities were created in both tibias of 40 male rats were divided into two groups: Control and Treaty. In this, the stressor stimulus was applied 40 days pre-operative and all post-operative days until sacrifice in the morning for 2 hours, by immobilizing restraint. These animals also received diazepam benzodiazepine group, daily, at a concentration of 5mg/Kg/peso body within 15 days of preoperative. In groups of five animals were sacrificed at 7, 14, 30 and 60 days post-surgery. At 7 days postoperatively, while the control group exhibited tissue rich in fibroblasts, the treated group showed newly formed tissue with few fibroblasts and capillaries along with lymphocytes and macrophages. At 14 days postsurgery, the control group showed newly formed trabecular bone while the treated group progressed to thin trabecular bone with numerous osteoblasts on their borders. At 30 days post-operative bone healing is complete in both groups. At 60 days post-operative characteristics observed in the treated and control groups are similar to the previous period, but with more advanced osteogenesis

Reação do tecido conjuntivo subcutâneo de ratos ao implante de Artglass®: estudo histológico / Reaction of the subcutaneous tissue of rats to Artglass™: histological study

Sistemas indiretos de resina composta têm sido rotineiramente indicados para confecção de restaurações em pacientes estressados. O propósito deste trabalho foi estudar histologicamente em ratos o efeito do estresse crônico sobre a reação do tecido conjuntivo subcutâneo ao implante de Artglass®. Para tanto, 60 ratos, divididos em quatro grupos (GI (controle), GII (estressado), GIII (Artglass®) e GIV (Artglass®/Estressado) receberam implante subcutâneo, bilateral e dorsal, de tubos de polietileno contendo soro fisiológico (Grupos I e II) ou Artglass® (Grupos III e IV). Em grupos de cinco, os animais foram sacrificados aos 7,14 e 28 dias pós-operatórios. Os resultados obtidos permitiram observar reação inflamatória mais intensa e organização do tecido conjuntivo mais tardia nos animais submetidos ao estresse

Indirect composite resin systems have been routinely recommended for making restorations in distressed patients. The purpose of this study was to evaluate histologically in rats the effect of chronic stress on the reaction of subcutaneous connective tissue after implant of Artglass™. For this purpose, 60 rats were divided into four groups (GI (control), GII (stressed), GIII (Artglass™) and GIV (Artglass™/ stressed) received dorsal subcutaneous implants of polyethylene tubes containing saline solution (GI and GII) or Artglass™ (GIII and GIV). In groups of four animals were sacrificed at 7,14 and 28 days postoperatively. The results allowed to observe more intense inflammatory reaction and tissue organization later in the animals subjected to stress

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.

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.

Histomorphometric analysis and immunolocalization of RANKL and OPG during the alveolar healing process in female ovariectomized rats treated with oestrogen or raloxifene.

OBJECTIVE: To investigate the effects of bone-resorption inhibitors (oestrogen and raloxifene) on the RANKL/OPG balance during the chronology of the alveolar healing process in ovariectomized (OVX) rats by means of immunocolocalization and histomorphometric analysis. MATERIALS AND METHODS: One hundred sixty female Wistar rats at 70 days of age were either OVX or sham-operated and divided into four groups: sham, OVX/Oil, OVX with E(2) replacement (17beta-estradiol, 400 microg/month), OVX with RLX treatment (1mg/kg bw/day). The 60-day treatment started 8 days after ovariectomy. The incisors were extracted to allow analysis of 7, 14, 21, 28 and 42 days of wound healing. After obtaining the histological samples, slides were stained with hematoxylin and eosin or subjected to immunocolocalization reaction for RANKL and OPG. Results were quantitatively evaluated. RESULTS: Histomorphometric analysis showed that the sham group presented the highest and OVX/Oil group the lowest mean bone formation value in the post-extraction period. The immunocolocalization analysis showed a larger increase in bone turnover at 7 postoperative days in OVX/Oil and sham groups and decreasing bone turnover in the other periods. The OVX/Oil group showed a large decrease in bone turnover at 14 postoperative days, a period demonstrated by mild cellular activity. OVX/E(2) and sham groups showed a decreased bone turnover at 28 postoperative days while OVX/RLX group showed a decreased bone turnover at 21 postoperative days. On the 42nd postoperative day, sham and OVX/RLX groups showed an established alveolar bone healing process. CONCLUSIONS: Ovariectomy delays the alveolar healing process and interferes with bone turnover through the balance between RANKL and OPG. Oestrogen replacement or raloxifene treatment did not totally recover the oestrogen-deficient state. However raloxifene treatment showed more satisfactory results than oestrogen replacement.

Osteocalcin immunolabeling during the alveolar healing process in ovariectomized rats treated with estrogen or raloxifene.

The influence of an estrogen-deficient state was evaluated in this study and also its treatments with estrogen (E(2)) or with raloxifene (RLX) on the expression of osteocalcin during the periods of the chronology of the alveolar bone healing process (7, 14, 21, 28 and 42 post-extraction days) by means of immunohistochemistry reactions and histomorphometric analysis. Rats (200-220 g) with oestrus cycles normal were either OVX or sham-operated and divided into four groups: sham, OVX control (OVX/O), estrogen (OVX/E(2); 17 beta-estradiol, 400 microg/mo) and raloxifene (OVX/RLX; 1 mg/kg bw/d) groups. Histomorphometric analysis showed the sham group presented the highest mean value of bone formation post-extraction. The reaction of immunohistochemistry for osteocalcin presented stronger expression of osteocalcin with predominance at 14 and 21 days on sham group. The OVX/RLX group presented better results than OVX/E(2), considering the expression of osteocalcin in osteoblastic lineage cells, but still inferior than the sham group. It was concluded that ovariectomy decreases the mineralization process and the osteocalcin expression during the chronology of the alveolar healing process that is not totally recovered with estrogen replacement or raloxifene treatment.

Comparison between laser therapy and non-surgical therapy for periodontitis in rats treated with dexamethasone.

The aim of this study was to compare low-level laser therapy (LLLT) as adjuvant treatment for induced periodontitis with scaling and root planing (SRP) in dexamethasone-treated rats. One-hundred twenty rats were divided into groups: D group (n = 60), treated with dexamethasone; ND group (n = 60) treated with saline solution. In both groups, periodontal disease was induced by ligature at the left first mandibular molar. After 7 days, the ligature was removed and all animals were subjected to SRP and were divided according to the following treatments: SRP, irrigation with saline solution (SS); SRP + LLLT, SS and laser irradiation (660 nm; 24 J; 0.428 W/cm(2)). Ten animals in each treatment were killed after 7 days, 15 days and 30 days. The radiographic and histometric values were statistically analyzed. In all groups radiographic and histometric analysis showed less bone loss (P < 0.05) in animals treated with SRP + LLLT in all experimental periods. SRP + LLLT was an effective adjuvant conventional treatment for periodontitis in rats treated with dexamethasone.