RESUMO
BACKGROUND: Psychologic stress and clinical hypercortisolism have been related to direct effects on bone metabolism. However, there is a lack of information regarding the outcomes of regenerative approaches under the influence of chronic stress (CS). Enamel matrix derivative (EMD) has been used in periodontal regenerative procedures, resulting in improvement of clinical parameters. Thus, the aim of this histomorphometric study is to evaluate the healing of periodontal defects after treatment with EMD under the influence of CS in the rat model. METHODS: Twenty Wistar rats were randomly assigned to two groups; G1: CS (restraint stress for 12 hours/day) (n = 10), and G2: not exposed to CS (n = 10). Fifteen days after initiation of CS, fenestration defects were created at the buccal aspect of the first mandibular molar of all animals from both groups. After the surgeries, the defects of each animal were randomly assigned to two subgroups: non-treated control and treated with EMD. The animals were euthanized 21 days later. RESULTS: G1 showed less bone density (BD) compared to G2. EMD provided an increased defect fill (DF) in G1 and higher BD and new cementum formation (NCF) in both groups. The number of tartrate-resistant acid phosphatase-positive osteoclasts was significantly higher in G1 when compared to G2 and in EMD-treated sites of both groups. CONCLUSIONS: CS may produce a significant detrimental effect on BD. EMD may provide greater DF compared to non-treated control in the presence of CS and increased BD and NCF in the presence or absence of CS.
Assuntos
Perda do Osso Alveolar/terapia , Proteínas do Esmalte Dentário/uso terapêutico , Estresse Fisiológico/fisiologia , Estresse Psicológico/fisiopatologia , Fosfatase Ácida/análise , Perda do Osso Alveolar/patologia , Animais , Densidade Óssea/efeitos dos fármacos , Densidade Óssea/fisiologia , Cementogênese/efeitos dos fármacos , Cementogênese/fisiologia , Cemento Dentário/efeitos dos fármacos , Cemento Dentário/cirurgia , Dentina/efeitos dos fármacos , Dentina/cirurgia , Isoenzimas/análise , Masculino , Mandíbula/efeitos dos fármacos , Mandíbula/patologia , Osteoclastos/patologia , Osteogênese/efeitos dos fármacos , Osteogênese/fisiologia , Ligamento Periodontal/efeitos dos fármacos , Ligamento Periodontal/cirurgia , Distribuição Aleatória , Ratos , Ratos Wistar , Estresse Psicológico/patologia , Fosfatase Ácida Resistente a TartaratoRESUMO
BACKGROUND: Diabetes mellitus (DM) involves metabolic changes that can negatively influence periodontal tissues, resulting in impaired periodontal repair. There is a lack of information about the outcomes of regenerative approaches under the influence of DM. Enamel matrix derivatives (EMDs) have been used in periodontal regenerative procedures, resulting in improvement of clinical parameters. Thus, the aim of this histomorphometric study is to evaluate the healing of periodontal defects after treatment with EMD under the influence of DM. METHODS: Twenty Wistar rats were randomly assigned to two groups: group 1 (G1): DM was induced with a single intraperitoneal injection of streptozotocin (STZ) (n = 10); group 2 (G2): rats were not exposed to STZ (n = 10). Seven days after DM induction, bilateral fenestration defects were created at the buccal aspect of the first mandibular molar. After the surgeries, the defects of each animal were randomly assigned to two subgroups: non-treated (control) and treated with EMD. The animals were euthanized 21 days later, and the percentage of defect fill (DF), newly formed bone density (BD), and new cementum formation (NCF) were histometrically assessed. The number of osteoclasts was determined by tartrate-resistant acid phosphatase. Weight and blood glucose were also analyzed. Mann-Whitney U test was used for comparison among groups and Wilcoxon test for comparison between the start and end times (weight and blood glucose) and between treatments (NCF and number of osteoclasts). One-way analysis of variance was used to assess DF and BD. Tukey test was used when the analysis of variance test detected significant differences (α = 5%). RESULTS: G1 (DM) showed less DF and BD compared with G2. EMD provided an increased DF in both groups and enhanced BD and NCF only in G2. The number of TRAP-positive osteoclasts was significantly higher in EMD-treated sites of G1. CONCLUSIONS: DM may produce a significant detrimental effect on BD. EMD may provide greater DF under diabetic or normal conditions; however, it may not significantly increase NCF in animals with DM.
Assuntos
Perda do Osso Alveolar/cirurgia , Proteínas do Esmalte Dentário/uso terapêutico , Diabetes Mellitus Experimental/fisiopatologia , Fosfatase Ácida/análise , Perda do Osso Alveolar/patologia , Animais , Glicemia/análise , Peso Corporal , Densidade Óssea/efeitos dos fármacos , Cementogênese/efeitos dos fármacos , Cemento Dentário/patologia , Diabetes Mellitus Experimental/sangue , Regeneração Tecidual Guiada Periodontal/métodos , Isoenzimas/análise , Masculino , Osteoclastos/patologia , Osteogênese/efeitos dos fármacos , Placebos , Distribuição Aleatória , Ratos , Ratos Wistar , Estreptozocina , Fosfatase Ácida Resistente a Tartarato , Fatores de Tempo , Resultado do Tratamento , Cicatrização/fisiologiaRESUMO
OBJECTIVES: There is a lack of histological information about the influence of cigarette smoke on bone around surface-treated implants. The aim of the present study was to test the influence of titanium surface treatment on osseointegration in animals that were exposed to intermittent cigarette smoke inhalation. MATERIAL AND METHODS: Twenty-two male Wistar rats were used. One tibia, chosen at random, received a machined titanium implant (MI) while the other received an aluminum oxide-blasted surface implant (ABI). The animals were randomly assigned to one of the following groups: Group 1 - control (n=11) and Group 2 - intermittent cigarette smoke inhalation (n=11). Sixty days after surgery, the animals were sacrificed. The degree of bone-to-implant contact (BIC), bone filling (BF) within the limits of the threads of the implants and bone density (proportion of mineralized bone in a 500-mum-wide zone lateral to the implant - BD) were measured in the cortical (zone A) and cancellous bone (zone B) areas. RESULTS: Data analysis showed significant differences when comparing the groups and implant surfaces in both zones for BIC (two-way ANOVA -P<0.05). The two groups presented higher BIC mean values for ABI, when compared with MI (P<0.05). In group 2, cigarette smoke inhalation negatively affected BF in both zones (P<0.05). Group 2 presented a significantly decreased BD in both zones (P<0.05). No statistically significant differences were observed between surfaces in any of the groups for BD. CONCLUSION: Within the limits of the present study, it can be concluded that the aluminum oxide blast surface treatment may increase the degree of BIC but cannot overcome the detrimental effect of tobacco smoke on bone around titanium implants.