In the dynamics of the bone healing, resorption and neoformation processes are dependent and rela... more In the dynamics of the bone healing, resorption and neoformation processes are dependent and related themselves. Proteins that are involved in the cell differentiation determinates the activation or inhibition of the activities that regulates the gain or the loose of bone mass. ...
International journal of oral and maxillofacial surgery, Jan 23, 2015
The aim of this study was to evaluate bone healing at the bone-implant interface in rats with ind... more The aim of this study was to evaluate bone healing at the bone-implant interface in rats with induced osteoporosis. The rats underwent a bilateral ovariectomy (OVX) and were fed a low calcium and phosphate diet. The OVX rats were divided into three groups: one was treated with raloxifene (OVX-RAL), one with alendronate (OVX-ALE), and one received no medication (OVX-NT). The control group rats (SHAM-DN) underwent sham surgery and were fed a normal diet. Each animal received one implant in each tibia: a machined surface implant in the right tibia and an implant with surface etching in the left tibia. All animals were euthanized after 42 days. Analysis of variance (ANOVA) and Tukey post hoc tests were applied to the biomechanics (reverse torque) and bone-implant contact (BIC) data (P<0.05). The RAL and ALE groups showed improved peri-implant bone healing. However, the ALE group showed no significant difference from the OVX-NT group. Surface treatment promoted higher corticalization ...
Clinical Implant Dentistry and Related Research, 2010
The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N... more The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N-butyl-2-cyanoacrilate (NB-Cn) for bone graft fixation. The aims of the study were: (a) to analyze the bone grafts volume maintenance fixed either with NB-Cn or titanium screw; (b) to assess the incorporation of onlay grafts on perforated recipient bed; and (c) the differences of expression level of tartrate-resistant acid phosphatase (TRAP) protein involved in bone resorption. Eighteen New Zealand White rabbits were submitted to calvaria onlay grafting on both sides of the mandible. On one side, the graft was fixed with NB-Cn, while on the other hand the bone graft was secured with an osteosynthesis screw. The computed tomography (CT) was performed just after surgery and at animals sacrifice, after 1 (n = 9) and 6 weeks (n = 9), in order to estimate the bone grafts volume along the experiments. Histological sections of the grafted areas were prepared to evaluate the healing of bone grafts and to assess the expression of TRAP protein. The CT scan showed better volume maintenance of bone grafts fixed with NB-Cn (p ≤ 0.05) compared with those fixed with screws, in both experimental times (analysis of variance). The immunohistochemical evaluation showed that the TRAP expression in a 6-week period was significantly higher compared with the 1-week period, without showing significant difference between the groups (Wilcoxon and Mann-Whitney). Histological analysis revealed that the NB-Cn caused periosteum damage, but provided bone graft stabilization and incorporation similar to the control group. The perforation provided by screw insertion into the graft during fixation may have triggered early revascularization and remodeling to render increased volume loss compared with the experimental group. These results indicate that the NB-Cn possesses equivalent properties to titanium screw to be used as bone fixation material in osteosynthesis.
ABSTRACT Introduction : The oral rehabilitation with dental implants is a very viable treatment m... more ABSTRACT Introduction : The oral rehabilitation with dental implants is a very viable treatment modality for patients. Therefore the discovery of osseointegration, dentistry has reached the trigger with respect to treatment with a high predictability of success. For this various principles, since the surgical protocols, the choice of material and even the technique for the manufacture of implant-supported prosthesis influence a good prognosis for treatment. Objective : Therefore, it is proposed this study a literature review of the fundamentals of osseointegration, explaining the historical and technical parameters of implantology, focusing in what the literature currently is studying with more intensity, the acceleration of osseointegration. Conclusion :well conducted procedures promotes the best aimed success in implantology. Rough surfaces shows great are for implant-bone contact and better mechanical results. The bone quality is fundamental in results foresigh. Keys words: Osseointegration. Prostheses and Implants. Mouth Rehabilitation
ABSTRACT Objectives: The aim of this study was to evaluate the interaction between polylactic pol... more ABSTRACT Objectives: The aim of this study was to evaluate the interaction between polylactic polyglycolic acid copolymer (PLA/PGA) associated or not to the bioactive glass in bone regeneration process of surgically created defects. Methods: forty male rats (rattus norvegicus albinus, Wistar) were used and two critical-size defects of 5 mm by trephine drill were made in their calvaria. Animals were divided in 4 groups according to the experimental defect filled: defect filled with blood clot (group C), defect filled with bioactive glass (BG) (Biogran 3 I ), defect filled with PLA/PGA copolymer (POLY) and defect filled with the association of PLA/PGA copolymer and bioactive glass (POLY/BG). Rats were euthanized at 7 and 30 post-operative days by anesthetic&#39;s overdose. After, the pieces obtained received laboratorial processing routine, with sections of 6 micrometers thickness that were stained with hematoxylin-eosin (H.E.) and Masson&#39;s Trichrome. The pieces were processed to immunoistochemistry analysis by means of the expression of proteins VEGF, BMP2, Cbfa1 and osteocalcin (OC) that are involved in vascularization, osteoinduction and bone mineralization process. Results: the Group C presented more expressive positive immunolabelings to proteins Cbfa1, BMP2 and OC, presenting better behavior, followed by groups BG, POLY/BG and POLY. At 7 days in all groups were observed the presence of connective tissue and discreet and restricted new bone formation only in the edge of the defect, no statistically significant (p=0,106). At 30 days, groups C and BG presented significantly more new bone formation than POLY and POLIY/BG (p=0,002). In group BG was observed the permanence of great amount of materials&#39; particles, involved with bone tissue not well differentiated. Conclusions: it was concluded that group C showed better behavior during bone regeneration process. All tested materials were biocompatible, however only the BG presented bone conductive properties. This study was supported by FAPESP (Process 06/54195-3).
Introdução: a mucosa bucal é susceptível a lesões de origem externa ou interna, causados por dife... more Introdução: a mucosa bucal é susceptível a lesões de origem externa ou interna, causados por diferentes agentes físicos, químicos e biológicos. Vários são os medicamentos testados para o tratamento das lesões da mucosa bucal. Objetivo: o propósito deste trabalho foi avaliar, microscopicamente em ratos, a reação do tecido conjuntivo subcutâneo ao implante de Hipoglós®. Material e Método: foram realizadas, no dorso de 15 animais incisões medindo 1 cm cada, com distância entre elas de 3 cm. A partir daí, dois grupos experimentais foram constituídos: Grupo I – Controle (tubo de polietileno vazio); Grupo II - Hipoglós® (tubo de polietileno contendo Hipoglós®), considerando os períodos de 7, 15 e 21 dias, com cinco animais em cada um. Resultados: na análise histológica, o Grupo II (Hipoglós®) mostrou ainda células inflamatórias aos 21 dias, apesar de estatisticamente esse grupo ter apresentado melhores resultados quando comparado ao grupo I (Controle). Conclusão: em razão dos seus compon...
This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell ... more This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell viability, and to evaluate drill wear by scanning electron microscopy. The tibiae of 10 rabbits were used, divided into 5 groups (G): G1 corresponded to new drills, and G2, G3, G4, and G5 corresponded to drills used 10, 20, 30, and 40 times, respectively. The animals received 10 sequential osteotomies in each tibia. The animals were euthanized immediately after the osteotomies by perfusion with 4% formaldehyde. Samples then underwent immunohistochemistry processing for ordinal qualitative analysis of osteoprotegerin (OPG), the RANK ligant (RANKL; a tumor-related necrosis factor receptor family), and osteocalcin protein immunolabels, as detected by the immunoperoxidase method and revealed with 3,3-diaminobenzidine. Drill wear and plastic deformation were analyzed by scanning electron microscopy (SEM). The proteins were expressed in osteocytes of the superior bone cortical during the 40 drillings. However, in G4 and G5, a discrete increase in the expression of RANKL was observed, when compared with OPG; this increase was statistically significant in G5 (P = .016). The SEM analysis revealed major plastic deformation and drill wear in G4 and G5. Based on the present methodology, it may be concluded that cell viability is preserved if a less traumatic surgical protocol is used. However, the repeated use of drills alters the protein balance as of the thirtieth perforation.
The purpose of this study was to evaluate the expression of proteins that participate in the oste... more 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. 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. 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. 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.
This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the r... more This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the repair after immediate and delayed replantation of rat teeth. Fifty-six Wistar rats (Rattus norvegicus albinus) had their maxillary right lateral incisor extracted and then replanted, according to the following conditions: group I (control; n = 8), teeth were not extracted; group II (n = 16), immediate replantation; group III (n = 16), delayed replantation without treatment; and group IV (n = 16), delayed replantation after root surface treatment (periodontal ligament removal and immersion in 2% acidulated-phosphate sodium fluoride) and calcium hydroxide intracanal dressing. Rats in group I were euthanized on the first day of the experiment, while the animals in the other groups were euthanized 10 and 60 days after replantation (n = 8/period). Hematoxylin and eosin-stained sections were obtained for histological analysis. The immunohistochemical analysis revealed expression of OPG and RANKL proteins in all groups and both postreplantation times, except for group II at 60 days. In the experimental groups, RANK expression was observed only at 10 days. In conclusion, there was strong immunostaining for the OPG-RANK-RANKL system at the earlier postreplantation time, suggesting a more effective participation of these proteins at the start of the healing process, as their expression decreased at 60 days.
... Paula Ervolino da Silva, Sônia Regina Panzarini, Roberta Okamoto, Wilson Roberto Poi, Celso K... more ... Paula Ervolino da Silva, Sônia Regina Panzarini, Roberta Okamoto, Wilson Roberto Poi, Celso Koogi Sonoda, Denise Pedrini Campus de Araçatuba Faculdade de Odontologia de Arçatuba Odontologia - paulaervolino@yahoo.com.br PIBIC/REITORIA. ...
This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the r... more This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the repair after immediate and delayed replantation of rat teeth. Fifty-six Wistar rats (Rattus norvegicus albinus) had their maxillary right lateral incisor extracted and then replanted, according to the following conditions: group I (control; n = 8), teeth were not extracted; group II (n = 16), immediate replantation; group III (n = 16), delayed replantation without treatment; and group IV (n = 16), delayed replantation after root surface treatment (periodontal ligament removal and immersion in 2% acidulated-phosphate sodium fluoride) and calcium hydroxide intracanal dressing. Rats in group I were euthanized on the first day of the experiment, while the animals in the other groups were euthanized 10 and 60 days after replantation (n = 8/period). Hematoxylin and eosin-stained sections were obtained for histological analysis. The immunohistochemical analysis revealed expression of OPG and RANKL proteins in all groups and both postreplantation times, except for group II at 60 days. In the experimental groups, RANK expression was observed only at 10 days. In conclusion, there was strong immunostaining for the OPG-RANK-RANKL system at the earlier postreplantation time, suggesting a more effective participation of these proteins at the start of the healing process, as their expression decreased at 60 days.
This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell ... more This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell viability, and to evaluate drill wear by scanning electron microscopy. The tibiae of 10 rabbits were used, divided into 5 groups (G): G1 corresponded to new drills, and G2, G3, G4, and G5 corresponded to drills used 10, 20, 30, and 40 times, respectively. The animals received 10 sequential osteotomies in each tibia. The animals were euthanized immediately after the osteotomies by perfusion with 4% formaldehyde. Samples then underwent immunohistochemistry processing for ordinal qualitative analysis of osteoprotegerin (OPG), the RANK ligant (RANKL; a tumor-related necrosis factor receptor family), and osteocalcin protein immunolabels, as detected by the immunoperoxidase method and revealed with 3,3-diaminobenzidine. Drill wear and plastic deformation were analyzed by scanning electron microscopy (SEM). The proteins were expressed in osteocytes of the superior bone cortical during the 40 drillings. However, in G4 and G5, a discrete increase in the expression of RANKL was observed, when compared with OPG; this increase was statistically significant in G5 (P = .016). The SEM analysis revealed major plastic deformation and drill wear in G4 and G5. Based on the present methodology, it may be concluded that cell viability is preserved if a less traumatic surgical protocol is used. However, the repeated use of drills alters the protein balance as of the thirtieth perforation.
In the dynamics of the bone healing, resorption and neoformation processes are dependent and rela... more In the dynamics of the bone healing, resorption and neoformation processes are dependent and related themselves. Proteins that are involved in the cell differentiation determinates the activation or inhibition of the activities that regulates the gain or the loose of bone mass. ...
International journal of oral and maxillofacial surgery, Jan 23, 2015
The aim of this study was to evaluate bone healing at the bone-implant interface in rats with ind... more The aim of this study was to evaluate bone healing at the bone-implant interface in rats with induced osteoporosis. The rats underwent a bilateral ovariectomy (OVX) and were fed a low calcium and phosphate diet. The OVX rats were divided into three groups: one was treated with raloxifene (OVX-RAL), one with alendronate (OVX-ALE), and one received no medication (OVX-NT). The control group rats (SHAM-DN) underwent sham surgery and were fed a normal diet. Each animal received one implant in each tibia: a machined surface implant in the right tibia and an implant with surface etching in the left tibia. All animals were euthanized after 42 days. Analysis of variance (ANOVA) and Tukey post hoc tests were applied to the biomechanics (reverse torque) and bone-implant contact (BIC) data (P<0.05). The RAL and ALE groups showed improved peri-implant bone healing. However, the ALE group showed no significant difference from the OVX-NT group. Surface treatment promoted higher corticalization ...
Clinical Implant Dentistry and Related Research, 2010
The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N... more The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N-butyl-2-cyanoacrilate (NB-Cn) for bone graft fixation. The aims of the study were: (a) to analyze the bone grafts volume maintenance fixed either with NB-Cn or titanium screw; (b) to assess the incorporation of onlay grafts on perforated recipient bed; and (c) the differences of expression level of tartrate-resistant acid phosphatase (TRAP) protein involved in bone resorption. Eighteen New Zealand White rabbits were submitted to calvaria onlay grafting on both sides of the mandible. On one side, the graft was fixed with NB-Cn, while on the other hand the bone graft was secured with an osteosynthesis screw. The computed tomography (CT) was performed just after surgery and at animals sacrifice, after 1 (n = 9) and 6 weeks (n = 9), in order to estimate the bone grafts volume along the experiments. Histological sections of the grafted areas were prepared to evaluate the healing of bone grafts and to assess the expression of TRAP protein. The CT scan showed better volume maintenance of bone grafts fixed with NB-Cn (p ≤ 0.05) compared with those fixed with screws, in both experimental times (analysis of variance). The immunohistochemical evaluation showed that the TRAP expression in a 6-week period was significantly higher compared with the 1-week period, without showing significant difference between the groups (Wilcoxon and Mann-Whitney). Histological analysis revealed that the NB-Cn caused periosteum damage, but provided bone graft stabilization and incorporation similar to the control group. The perforation provided by screw insertion into the graft during fixation may have triggered early revascularization and remodeling to render increased volume loss compared with the experimental group. These results indicate that the NB-Cn possesses equivalent properties to titanium screw to be used as bone fixation material in osteosynthesis.
ABSTRACT Introduction : The oral rehabilitation with dental implants is a very viable treatment m... more ABSTRACT Introduction : The oral rehabilitation with dental implants is a very viable treatment modality for patients. Therefore the discovery of osseointegration, dentistry has reached the trigger with respect to treatment with a high predictability of success. For this various principles, since the surgical protocols, the choice of material and even the technique for the manufacture of implant-supported prosthesis influence a good prognosis for treatment. Objective : Therefore, it is proposed this study a literature review of the fundamentals of osseointegration, explaining the historical and technical parameters of implantology, focusing in what the literature currently is studying with more intensity, the acceleration of osseointegration. Conclusion :well conducted procedures promotes the best aimed success in implantology. Rough surfaces shows great are for implant-bone contact and better mechanical results. The bone quality is fundamental in results foresigh. Keys words: Osseointegration. Prostheses and Implants. Mouth Rehabilitation
ABSTRACT Objectives: The aim of this study was to evaluate the interaction between polylactic pol... more ABSTRACT Objectives: The aim of this study was to evaluate the interaction between polylactic polyglycolic acid copolymer (PLA/PGA) associated or not to the bioactive glass in bone regeneration process of surgically created defects. Methods: forty male rats (rattus norvegicus albinus, Wistar) were used and two critical-size defects of 5 mm by trephine drill were made in their calvaria. Animals were divided in 4 groups according to the experimental defect filled: defect filled with blood clot (group C), defect filled with bioactive glass (BG) (Biogran 3 I ), defect filled with PLA/PGA copolymer (POLY) and defect filled with the association of PLA/PGA copolymer and bioactive glass (POLY/BG). Rats were euthanized at 7 and 30 post-operative days by anesthetic&#39;s overdose. After, the pieces obtained received laboratorial processing routine, with sections of 6 micrometers thickness that were stained with hematoxylin-eosin (H.E.) and Masson&#39;s Trichrome. The pieces were processed to immunoistochemistry analysis by means of the expression of proteins VEGF, BMP2, Cbfa1 and osteocalcin (OC) that are involved in vascularization, osteoinduction and bone mineralization process. Results: the Group C presented more expressive positive immunolabelings to proteins Cbfa1, BMP2 and OC, presenting better behavior, followed by groups BG, POLY/BG and POLY. At 7 days in all groups were observed the presence of connective tissue and discreet and restricted new bone formation only in the edge of the defect, no statistically significant (p=0,106). At 30 days, groups C and BG presented significantly more new bone formation than POLY and POLIY/BG (p=0,002). In group BG was observed the permanence of great amount of materials&#39; particles, involved with bone tissue not well differentiated. Conclusions: it was concluded that group C showed better behavior during bone regeneration process. All tested materials were biocompatible, however only the BG presented bone conductive properties. This study was supported by FAPESP (Process 06/54195-3).
Introdução: a mucosa bucal é susceptível a lesões de origem externa ou interna, causados por dife... more Introdução: a mucosa bucal é susceptível a lesões de origem externa ou interna, causados por diferentes agentes físicos, químicos e biológicos. Vários são os medicamentos testados para o tratamento das lesões da mucosa bucal. Objetivo: o propósito deste trabalho foi avaliar, microscopicamente em ratos, a reação do tecido conjuntivo subcutâneo ao implante de Hipoglós®. Material e Método: foram realizadas, no dorso de 15 animais incisões medindo 1 cm cada, com distância entre elas de 3 cm. A partir daí, dois grupos experimentais foram constituídos: Grupo I – Controle (tubo de polietileno vazio); Grupo II - Hipoglós® (tubo de polietileno contendo Hipoglós®), considerando os períodos de 7, 15 e 21 dias, com cinco animais em cada um. Resultados: na análise histológica, o Grupo II (Hipoglós®) mostrou ainda células inflamatórias aos 21 dias, apesar de estatisticamente esse grupo ter apresentado melhores resultados quando comparado ao grupo I (Controle). Conclusão: em razão dos seus compon...
This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell ... more This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell viability, and to evaluate drill wear by scanning electron microscopy. The tibiae of 10 rabbits were used, divided into 5 groups (G): G1 corresponded to new drills, and G2, G3, G4, and G5 corresponded to drills used 10, 20, 30, and 40 times, respectively. The animals received 10 sequential osteotomies in each tibia. The animals were euthanized immediately after the osteotomies by perfusion with 4% formaldehyde. Samples then underwent immunohistochemistry processing for ordinal qualitative analysis of osteoprotegerin (OPG), the RANK ligant (RANKL; a tumor-related necrosis factor receptor family), and osteocalcin protein immunolabels, as detected by the immunoperoxidase method and revealed with 3,3-diaminobenzidine. Drill wear and plastic deformation were analyzed by scanning electron microscopy (SEM). The proteins were expressed in osteocytes of the superior bone cortical during the 40 drillings. However, in G4 and G5, a discrete increase in the expression of RANKL was observed, when compared with OPG; this increase was statistically significant in G5 (P = .016). The SEM analysis revealed major plastic deformation and drill wear in G4 and G5. Based on the present methodology, it may be concluded that cell viability is preserved if a less traumatic surgical protocol is used. However, the repeated use of drills alters the protein balance as of the thirtieth perforation.
The purpose of this study was to evaluate the expression of proteins that participate in the oste... more 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. 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. 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. 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.
This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the r... more This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the repair after immediate and delayed replantation of rat teeth. Fifty-six Wistar rats (Rattus norvegicus albinus) had their maxillary right lateral incisor extracted and then replanted, according to the following conditions: group I (control; n = 8), teeth were not extracted; group II (n = 16), immediate replantation; group III (n = 16), delayed replantation without treatment; and group IV (n = 16), delayed replantation after root surface treatment (periodontal ligament removal and immersion in 2% acidulated-phosphate sodium fluoride) and calcium hydroxide intracanal dressing. Rats in group I were euthanized on the first day of the experiment, while the animals in the other groups were euthanized 10 and 60 days after replantation (n = 8/period). Hematoxylin and eosin-stained sections were obtained for histological analysis. The immunohistochemical analysis revealed expression of OPG and RANKL proteins in all groups and both postreplantation times, except for group II at 60 days. In the experimental groups, RANK expression was observed only at 10 days. In conclusion, there was strong immunostaining for the OPG-RANK-RANKL system at the earlier postreplantation time, suggesting a more effective participation of these proteins at the start of the healing process, as their expression decreased at 60 days.
... Paula Ervolino da Silva, Sônia Regina Panzarini, Roberta Okamoto, Wilson Roberto Poi, Celso K... more ... Paula Ervolino da Silva, Sônia Regina Panzarini, Roberta Okamoto, Wilson Roberto Poi, Celso Koogi Sonoda, Denise Pedrini Campus de Araçatuba Faculdade de Odontologia de Arçatuba Odontologia - paulaervolino@yahoo.com.br PIBIC/REITORIA. ...
This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the r... more This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the repair after immediate and delayed replantation of rat teeth. Fifty-six Wistar rats (Rattus norvegicus albinus) had their maxillary right lateral incisor extracted and then replanted, according to the following conditions: group I (control; n = 8), teeth were not extracted; group II (n = 16), immediate replantation; group III (n = 16), delayed replantation without treatment; and group IV (n = 16), delayed replantation after root surface treatment (periodontal ligament removal and immersion in 2% acidulated-phosphate sodium fluoride) and calcium hydroxide intracanal dressing. Rats in group I were euthanized on the first day of the experiment, while the animals in the other groups were euthanized 10 and 60 days after replantation (n = 8/period). Hematoxylin and eosin-stained sections were obtained for histological analysis. The immunohistochemical analysis revealed expression of OPG and RANKL proteins in all groups and both postreplantation times, except for group II at 60 days. In the experimental groups, RANK expression was observed only at 10 days. In conclusion, there was strong immunostaining for the OPG-RANK-RANKL system at the earlier postreplantation time, suggesting a more effective participation of these proteins at the start of the healing process, as their expression decreased at 60 days.
This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell ... more This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell viability, and to evaluate drill wear by scanning electron microscopy. The tibiae of 10 rabbits were used, divided into 5 groups (G): G1 corresponded to new drills, and G2, G3, G4, and G5 corresponded to drills used 10, 20, 30, and 40 times, respectively. The animals received 10 sequential osteotomies in each tibia. The animals were euthanized immediately after the osteotomies by perfusion with 4% formaldehyde. Samples then underwent immunohistochemistry processing for ordinal qualitative analysis of osteoprotegerin (OPG), the RANK ligant (RANKL; a tumor-related necrosis factor receptor family), and osteocalcin protein immunolabels, as detected by the immunoperoxidase method and revealed with 3,3-diaminobenzidine. Drill wear and plastic deformation were analyzed by scanning electron microscopy (SEM). The proteins were expressed in osteocytes of the superior bone cortical during the 40 drillings. However, in G4 and G5, a discrete increase in the expression of RANKL was observed, when compared with OPG; this increase was statistically significant in G5 (P = .016). The SEM analysis revealed major plastic deformation and drill wear in G4 and G5. Based on the present methodology, it may be concluded that cell viability is preserved if a less traumatic surgical protocol is used. However, the repeated use of drills alters the protein balance as of the thirtieth perforation.
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