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

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.

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.

Digital Smile Design and mock-up technique in esthetic crown lengthening: 2-year follow-up of six cases.

The present case series aimed to evaluate the use of a Digital Smile Design (DSD) and mock-up technique for esthetic crown lengthening (ECL) surgery in six clinical cases with a 2-year follow-up. Six nonsmoker patients (five females, one male; aged 22 to 32 years), periodontally and systemically healthy, with inadequate tooth width/height ratio proportions associated with a gingival misalignment in the anterior maxilla were included. The DSDs were created using PowerPoint for all patients to evaluate gingival level and tooth form/contour. A wax-up and mock-up were created based on the DSD measurements. ECL surgeries were performed in all cases using the mock-up technique to determine the final gingival margin position and the amount of bone resection needed. A mock-up to bone crest distance of 3 mm was obtained in all cases. Using patient photographs, comparisons were made between the dental crown length (DCL) measurements obtained before the surgical procedure (baseline; T0), on the DSD template immediately postoperatively (IPO; T1), and at the 2-year follow-up (T2). A DCL augmentation of 1.16 ± 0.68 mm was obtained at T1, with an augmentation of 1.03 ± 0.73 mm at T2. Moreover, a minimal difference of 0.34 ± 0.74 mm between the DCL planned in the DSD template and the DCL obtained IPO was observed. In conclusion, the ECL procedure based on the DSD concept and mock-up technique proposed in this cases series was a predictable protocol for smile disharmony treatment in all the patients.

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

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/ß-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.

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.

Low-level laser therapy (LLLT) in sites grafted with osteoconductive bone substitutes improves osseointegration.

The aim of this study was to evaluate the osseointegration of implants placed in areas grafted with different osteoconductive bone substitutes irradiated with infrared low-level laser therapy (LLLT). Fifty-six rats were randomly allocated into 4 groups: DBB, bone defects filled with deproteinized bovine bone graft (DBB); HA/TCP, bone defects filled with biphasic ceramic made of hydroxyapatite and ß-tricalcium phosphate (HA/TCP); DBB-L, bone defects filled with DBB and treated by LLLT; HA/TCP-L, bone defects filled with HA/TCP and treated by LLLT. Bone defects were performed in the tibia of each animal and filled with the different biomaterials. The grafted areas were treated with LLLT (λ 808 nm, 100 mW, ϕ ∼ 0.60 mm) in 7 sessions with 48 h between the irradiations. After the 60-day period, the implants were placed, and the animals were euthanized after 15 and 45 days. The osseointegration and bone repair in the grafted area were evaluated by biomechanical, microtomographic and histometric analyses, and the expression of some bone biomarkers was evaluated by immunohistochemistry analysis. LLLT induced higher degree of osseointegration, which was associated with the greater expression of BMP2 and OCN. LLLT performed in areas grafted with osteoconductive bone substitutes prior to implant placement improves osseointegration.

Esthetic crown lengthening in the treatment of gummy smile.

The aim of this article was to evaluate 1 year after surgery a surgical protocol that included gingivectomy and an apically positioned flap plus osseous resective surgery to correct excessive gingival display (EGD) in patients with altered passive eruption (APE) of the maxillary anterior teeth. Six female patients aged 18 to 22 years were diagnosed with APE type 1B. Surgical crown lengthening with flap surgery and bone recontouring was performed to achieve the biologic width. Photographic images were analyzed to evaluate the stable improvement of crown length before the procedure (baseline), immediately after surgery (immediate postoperative), and at 3 and 12 months postsurgery. Moreover, a lip repositioning procedure was also performed in one case to complement the periodontal therapy. Compared with baseline, an increase of 1.6 mm in the mean tooth crown height was observed in the photographic analysis at 12 months. A minimal difference was observed between the mean tooth crown height immediate postoperative and at 12 months, which indicates stability of the gingival margin. In conclusion, the surgical protocol outlined in this article describing esthetic crown lengthening for the treatment of APE/gummy smile resulted in predictable outcomes and stability of the gingival margin 1 year after surgery.

Loading deproteinized bovine bone with strontium enhances bone regeneration in rat calvarial critical size defects.

OBJECTIVE: To evaluate the effect of grafting with strontium (Sr)-loaded deproteinized bovine bone (DBB) on bone healing in calvarial critical size defects (CSD) in rats. MATERIAL AND METHODS: Two circular bone defects (5 mm in diameter) were created in the calvaria of 42 rats. One of the defects, randomly chosen, was grafted with (a) DBB, (b) DBB loaded with 19.6 µg/g of Sr (DBB/Sr1), or (c) DBB loaded with 98.1 µg/g of Sr (DBB/Sr2). The other defect was left empty as negative control. Groups of seven animals from each of the groups were euthanized 15 and 60 days post-op. Bone healing in the CSD was evaluated by micro-CT and histology/histomorphometry and immunohistochemistry. RESULTS: DBB/Sr2-grafted sites showed statistically significantly shorter radiographic residual defect length compared with DBB/Sr1- and DBB-grafted sites, and with empty controls at 60 days. Further, the amount of new bone formation in the DBB/Sr1- and DBB/Sr2-grafted sites was significantly higher compared with that in the DBB-grafted sites at 60 days. A larger number of DBB/Sr1- and DBB/Sr2-grafted sites presented with no- or only limited to mild inflammation, compared with the DBB-grafted sites, especially at 60 days. Higher expression of osteocalcin was observed in DBB/Sr1- and DBB/Sr2-grafted sites as compared to DBB-grafted sites. CONCLUSION: Grafting with Sr-loaded DBB enhanced bone formation in CSD in rats, when compared with grafting with non-loaded DBB. CLINICAL RELEVANCE: Grafting with Sr-loaded DBB may enhance bone formation in bone defects.

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.