Osseointegration of implants with superhydrophilic surfaces in rats with high serum levels of nicotine

Abstract This study aimed to evaluate the effect of nicotine administration on the osseointegration of a superhydrophilic implants surface on rat tibiae. Thirty-two rats were used and divided into 2 groups according to the administration or not of nicotine: HH - Installation of implants with superhydrophilic surfaces in healthy animals; and HN - Installation of implants with superhydrophilic surfaces in animals subjected to nicotine administration. The animals were euthanized 15 and 45 days after implant placement (n = 8). Osseointegration was assessed by means of biomechanical analyses (removal torque), microcomputed tomography (volume of bone around the implants- %BV/TV), and histomorphometry (bone-implant contact -%BIC and the bone area between implant threads -%BBT). The animals subject to the nicotine administration presented lower removal torque than the control animals at the 45-day period (21.88 ± 2.80 Ncm vs. 17.88 ± 2.10 Ncm). The implants placed in the control rats presented higher %BIC (54.26 ± 6.59% vs. 39.25 ± 4.46%) and %BBT (50.57 ± 5.28% vs. 32.25 ± 5.24%) than the implants placed in nicotine animals at 15-day period. The nicotine administration reduces the osseointegration at 15 days, however, the superhydrophilic surface equalized the osseointegration in nicotine-exposed animals compared with healthy animals after 45 days of implant placement.

Resumo O objetivo deste estudo foi avaliar o efeito da administração de nicotina na osseointegração de implantes com superfície modificada por jateamento de oxidos e ataque ácido instalados em tíbia de ratos. Foram utilizados 32 ratos que foram divididos em 2 grupos de acordo com a administração ou não de nicotina: HH - Instalação de implantes com superfícies superhidrofílicas em animais sadios; e HN - Instalação de implantes com superfícies superhidrofílicas em animais submetidos à administração de nicotina. Os animais foram eutanasiados 15 e 45 dias após a colocação do implante (n = 8). A osseointegração foi avaliada por meio de análises biomecânicas (torque de remoção), microtomografia (volume de osso ao redor dos implantes - %BV/TV) e histomorfometrica (contato osso-implante -%BIC e área óssea entre roscas do implante -%BBT). Os animais submetidos à administração de nicotina apresentaram menor torque de remoção do que os animais controle no período de 45 dias (21,88 ± 2,80 Ncm vs. 17,88 ± 2,10 Ncm). Os implantes colocados nos ratos controle apresentaram maiores %BIC (54,26 ± 6,59% vs. 39,25 ± 4,46%) e %BBT (50,57 ± 5,28% vs. 32,25 ± 5,24%) do que os implantes colocados nos animais submetidos a administração de nicotina no período de 15 dias. A administração de nicotina prejudicou a osseointegração no período de 15 dias. Entretanto, a superfície superhidrofílica equalizou a osseointegração em animais expostos à nicotina em comparação com animais saudáveis após 45 dias da colocação do implante.

Effect of different low-level intensity laser therapy (LLLT) irradiation protocols on the osseointegration of implants placed in grafted areas

Abstract Objective To evaluate the effect of different protocols of low-level intensity laser therapy (LLLT) irradiation on the osseointegration of implants placed in grafted areas. Methodology 84 rats were randomly allocated into six groups: DBB: defect filled with deproteinized bovine bone; HA/TCP: defect filled with biphasic ceramic of hydroxyapatite/β-tricalcium phosphate ; DBB-LI: defect filled with DBB and treated with LLLT after implant placement; HA/TCP-LI: defect filled with HA/TCP and treated with LLLT after implant placement; DBB-LIB: defect filled with DBB and treated with LLLT after graft procedure and implant placement; and HA/TCP-LIB: defect filled HA/TCP and treated with LLLT after graft procedure and implant placement. The bone defects were made in the tibia and they were grafted. After 60 days, the implants were placed. The rats were subsequently subjected to euthanasia 15 and 45 days after implant placement. The pattern of osseointegration and bone repair in the grafted area was evaluated by biomechanical, microtomographic, and histometric analyses. Furthermore, the expression of bone biomarker proteins was assessed. Results The LLLT groups presented higher removal torque, mineralized tissue volume, and a greater degree of osseointegration, especially when LLLT was performed only after implant placement, and these findings were associated with higher expression of BMP2 and alkaline phosphatase. Conclusion LLLT performed on implants placed in grafted areas enhances the osseointegration process.

Bone repair induced by different bone graft substitutes in critical-sized defects in rat calvaria / Avaliação do reparo ósseo induzido por diferentes substitutos ósseos em modelo de defeito crítico de calvária de ratos

Abstract Introduction The use of bone substitutes in grafting procedures as an alternative of the use of autogenous bone graft has been indicated, however, the direct comparison between these biomaterials has been little explored. Objective To evaluate the effect of different osteoconductive bone substitutes on the bone repair in critical-sized defects (CSDs) in rat calvaria. Material and method One CSD with an 8 mm diameter was made in each of the 40 rats used in this study. The animals were randomly allocated into 5 groups (n=8), according to the type of bone substitute used to fill the CSD: COA (Coagulum); AUT (autogenous bone); DBB (deproteinized bovine bone graft); HA/TCP (biphasic ceramic composed of hydroxyapatite and β-phosphate tricalcium); and TCP (β-phosphate tricalcium). A microtomographic analysis was performed to evaluate the remaining defect linear length (DLL) of the CSD and the volume of the mineralized tissues (MT) within the CSD at 3, 7, 15 and 30 days after the surgical procedure. In addition, a histometric analysis was performed to evaluate the composition of the repaired bone tissue (% Bone and % Biomaterial) at the 30-day period. Result It was shown that the COA had the lowest DLL and MT within the CSD. In addition, the COA presented the highest % of bone in CSD. The DBB had a higher MT and a higher % of bone substitute particles in the CSD than the AUT and TCP groups. The DBB and AUT groups presented higher % of bone in the CSD than the TCP group. Conclusion The use of the DBB promoted a better pattern of bone volume gain and formation compared to TCP and HA / TCP but was biologically inferior to the AUT.

Resumo Introdução A utilização de substitutos ósseos em procedimentos de enxertia de forma alternativa ao uso do osso autógeno tem sido indicada, entretanto a comparação direta entre esses biomateriais tem sido pouco explorada. Objetivo Avaliar o efeito de diferentes biomateriais osteocondutores sobre o reparo de defeitos críticos em calvárias (DCC) de ratos. Material e método Foram utilizados 40 ratos que foram submetidos a confecção de um DCC com 8 mm de diâmetro. Os animais foram aleatoriamente divididos em 5 grupos com 8 animais, de acordo com o tipo de biomaterial utilizado para preencher os DCC: Grupo COA (coágulo); Grupo AUT (osso autógeno); Grupo OBD (osso bovino desproteinizado); Grupo HA/ TCP (cerâmica bifásica composta de hidroxiapatita e β fosfato tricálcio); Grupo TCP (β fosfato tricálcio). Foram executadas análise microtomográfica para avaliação do comprimento linear remanescente (DLL) do DCC e o volume dos tecidos mineralizados (MT) dentro do DCC nos períodos de 3, 7, 15 e 30 dias após cirurgia. Adicionalmente, foi executado análise histométrica para avaliar a composição do tecido ósseo reparado (% Osso e % Biomaterial) no período de 30 dias. Resultado O grupo COA apresentou o menor DLL e MT dentro do DCC e maior % osso do que os outros grupos. O grupo OBD apresentou maior volume de tecidos mineralizados e maior % biomaterial do que o grupo os grupos AUT e TCP. Os grupos OBD e AUT apresentaram maior % osso que o grupo TCP. Conclusão O OBD promoveu melhor padrão de aumento de disponibilidade óssea e qualidade do osso reparado em comparação ao TCP e HA/TCP, porém biologicamente inferior ao grupo AUT.