Protein interactions with osseointegrable titanium implants

This review aims to present the mechanisms of protein interactions with titanium dental implant surfaces. Methods: the analyses were based on searches of scientific articles available in English and Portuguese in PubMed (MEDLINE), Bireme (LILACS), Scielo, Web of Science and Google Scholar. Results: titanium dental implant treatments success rates (95-98%) are mainly due to the biocompatibility of titanium oxide on the implant surface, surgical techniques adopted, good implants manufacturing processes and biomechanical knowledge of the systems. Studies in past decades has empirically developed implant surfaces with significant changes in morphologies, roughness, wettability, surface energy, chemical composition, and chemical groups density or deposited molecules. These changes promoted better protein adsorption, osteoblast adhesion, and changes in the mechanisms involved in osseointegration. Thus, the time to put the implant in function has been reduced and the success rates have increased. In the osseointegration process, at the nanoscale, there is no contact between the bone and the implant surface, but there is the formation of a protein anchorage between the periosteum and the implant with an interface formed by proteins. In all the reactions between the body and the implant surface, the activities of fibronectin and integrin are essential, since they are responsible for transmitting information to the cell for its differentiation, adhesion and mobility. Conclusion: thus, the analyses of protein-implant interactions are indispensable for a better understanding of the performance of osseointegrated dental implants

Mid-term effectiveness of hip preservation in the reconstruction of ultrashort bone segments in the proximal femur with three-dimensional printed customized cementless intercalary endoprosthesis with an intra-neck curved stem / 中国修复重建外科杂志

OBJECTIVE@#To explore the design points of a three-dimensional (3D) printed customized cementless intercalary endoprosthesis with an intra-neck curved stem and to evaluate the key points and mid-term effectiveness of its application in the reconstruction of ultrashort bone segments in the proximal femur.@*METHODS@#Between October 2015 and January 2021, 17 patients underwent reconstruction with a 3D printed-customized cementless intercalary endoprosthesis with an intra-neck curved stem. There were 11 males and 6 females, the age ranged from 10 to 76 years, with an average of 30.1 years. There were 9 cases of osteosarcoma, 4 cases of Ewing sarcoma, 2 cases of chondrosarcoma, 1 case of liposarcoma, and 1 case of myofibroblastoma. The disease duration was 5-14 months, with an average of 9.5 months. Enneking staging included 16 cases of stage ⅡB and 1 case of stage ⅢB. The distances from the center of the femoral head to the body midline and the acetabular apex were measured preoperatively on X-ray images. Additionally, the distances from the tip of the intra-neck curved stem to the body midline and the acetabular apex were measured at immediate postoperatively and last follow-up. The neck-shaft angle was also measured preoperatively, at immediate postoperatively, and at last follow-up. The status of osseointegration at the bone-prosthesis interface and bone growth into the prosthesis surface were assessed by X-ray films, CT, and Tomosynthesis-Shimadzu metal artefact reduction technology (T-SMART). The survival status of the patients, presence of local recurrence or distant metastasis, and occurrence of postoperative complications were assessed. The recovery of lower limb function was evaluated pre- and post-operatively using the Musculoskeletal Tumor Society (MSTS) scoring system, and pain relief was evaluated using the visual analogue scale (VAS) scores.@*RESULTS@#The patient's femoral resection length was (163.1±57.5) mm, the remaining proximal femoral length was (69.6±9.3) mm, and the percentage of femoral resection length/total femoral length was 38.7%±14.6%. All 17 patients were followed up 25-86 months with an average of 58.1 months. During the follow-up, 1 patient died of lung metastasis at 46 months postoperatively, and the remaining 16 patients survived tumor-free. There was no complication such as periprosthetic infection, delayed incision healing, aseptic loosening, prosthesis fracture, or periprosthetic fracture. No evidence of micromotion or wear around the implanted stem of the prosthesis was detected in X-ray and T-SMART evaluations. There was no significant radiolucent lines, and radiographic evidence of bone ingrowth into the bone-prosthesis interface was observed in all stems. There was no significant difference in the distance from the tip of the curved stem to the body midline and the apex of the acetabulum at immediate postoperatively and last follow-up compared with the distance from the center of the femoral head to the body midline and the apex of the acetabulum before operation, respectively (P>0.05), and there was no significant difference in the above indexes between immediate postoperatively and last follow-up (P>0.05). The differences in the neck-shaft angle at various time points before and after operation were also not significant (P>0.05). At last follow-up, the MSTS score was 26.1±1.2 and the VAS score was 0.1±0.5, which were significantly improved when compared with those before operation [19.4±2.1 and 5.7±1.0, respectively] (t=14.735, P<0.001; t=21.301, P<0.001). At last follow-up, none of the patients walked with the aid of crutches or other walkers.@*CONCLUSION@#The 3D printed customized cementless intercalary endoprosthesis with an intra-neck curved stem is an effective method for reconstructing ultrashort bone segments in the proximal femur following malignant tumor resection. The operation is reliable, the postoperative lower limb function is satisfactory, and the incidence of complications is low.

Influência de espessuras de fibromucosa e de material reembasador de próteses totais na distribuição de tensões sobre implantes cone morse durante fase de osseointegração: análise pelo método dos elementos finitos - 3D / Influence of fibromucosal thickness and reline material of complete dentures on stress distribution on cone morse implants during osseointegration phase: analysis by the finite element method - 3D

Durante o período de osseointegração de implantes em uma reabilitação oral com prótese do tipo protocolo ou overdenture, uma prótese total convencional provisória poderá ser utilizada e revestida com materiais reembasadores macios, os quais têm por objetivo reduzir o estresse para a interface ossoimplante. A avaliação mecânica de tal situação clínica é de extrema relevância, a fim de se estabelecer protocolos mais seguros durante esta fase inicial da implantodontia. O objetivo deste estudo foi realizar uma análise biomecânica pelo método dos elementos finitos 3D, da distribuição de tensões durante a fase provisória de reabilitação com implantes osseointegrados simulando uma situação clínica de protocolo/overdenture inferior sobre 4 implantes do tipo cone morse, na fase de cicatrização. Para este estudo foram confeccionados 6 modelos 3D, sob carregamento em 2 direções (vertical e oblíquo em relação ao plano oclusal), simulando osso tipo II, variando a altura do tecido gengival (2 mm e 3 mm) e a espessura do material reembasador (0 mm - sem material, 2 mm e 4 mm), sendo utilizado um cicatrizador compatível com a altura + 0,5 mm para cada situação gengival. A posição dos 4 implantes cone morse (UNITITE, UCM 3510N, SIN) foi sempre a mesma, nas posições perdidas dos dentes 46, 43, 33 e 36. Para a altura gengival de 2 mm foi utilizado cicatrizador de 2,5 mm de altura (UNITITE, CIMU 4525, SIN) e para a altura gengival de 3 mm, o cicatrizador de 3,5 mm de altura (UNITITE, CIMU 4535, SIN). Os modelos utilizados foram: (G2C2,5-SR) altura gengival de 2mm, cicatrizador de 2,5mm, sem material reembasador; (G2C2,5-R2) altura gengival de 2mm, cicatrizador de 2,5mm, com soft rreembasador de 2mm; (G2C2,5-R4) altura gengival de 2mm, cicatrizador de 2,5mm, com material reembasador de 4mm; (G3C3,5-SR) altura gengival de 3mm, cicatrizador de 3,5mm, sem material reembasador; (G3C3,5-R2) altura gengival de 3mm, cicatrizador de 3,5mm, e reembasador de 2mm e (G3C3,5-R4) altura gengival de 3mm, cicatrizador de 3,5mm e soft reembasador de 4mm. A metodologia para modelagem se baseou em um escaneamento de superfície de uma prótese total inferior montada, sob um modelo inferior padrão, e de seu modelo de assentamento. As geometrias dos implantes (CM 3,5x10mm) e de seus cicatrizadores foram obtidas por simplificação do desenho dos mesmos no programa SolidWorks e no programa Rhinoceros 3D. O software utilizado para análise foi o ANSYS 17.0. A visualização dos resultados foi qualitativa através de mapas de deslocamento, von Mises e tensão máxima principal. As regiões com maiores deslocamentos foram as dos implantes mais anteriores (#33 e #43), sendo os do modelo 6 submetidos a forças verticais os que apresentaram maiores deslocamentos, próximos a 0,05 mm. A força oblíqua, de forma geral, tendeu a sobrecarregar mais os implantes do lado onde as cargas foram aplicadas. No tecido ósseo foi possível observar que o osso cortical se mostrou com mais concentração de tensão de tração que o osso trabecular. A utilização do material reembasador gerou menores tensões transmitidas para o tecido gengival, concentrando estas tensões principalmente no material reembasador. A não utilização de material reembasador aumenta as concentrações de tensões nos implantes/cicatrizadores, independentemente de sua espessura ou da espessura gengival. Concluiu-se que o uso de reembasador soft diminuiu as tensões nos implantes/cicatrizadores e tecido gengival; o aumento da espessura do material reembasador não influenciou na diminuição das tensões aos tecidos de suporte e tecidos gengivais mais espessos foram favoráveis em diminuir as tensões transmitidas ao tecido ósseo, mas concentram mais tensões nos implantes/cicatrizadores(AU)

During the period of osseointegration of implants in an oral rehabilitation with a protocol or overdenturetype prosthesis, a conventional temporary complete denture can be used and coated with soft reline materials, which aim to reduce the stress to the bone-implant interface. The mechanical assessment of such a clinical situation is extremely relevant in order to establish safer protocols during this initial phase of implantology. The objective of this study was to perform a biomechanical analysis by the 3D finite element method, of the stress distribution during the provisional phase of rehabilitation with osseointegrated implants simulating a clinical situation of protocol/lower overdenture on 4 cone morse implants, in the healing phase. For this study, 6 3D models were made, under loading in 2 directions (vertical and oblique in relation to the occlusal plane), simulating type II bone, varying the height of the gingival tissue (2 mm and 3 mm) and the thickness of the reline material (0 mm - without material, 2 mm and 4 mm), using a healer compatible with the height + 0.5 mm for each gingival situation. The position of the 4 cone morse implants (UNITITE, UCM 3510N, SIN) was always the same, in the missing positions of teeth 46, 43, 33 and 36. For the 2 mm gingival height, a 2.5 mm high healer was used. (UNITITE, CIMU 4525, SIN) and for a gingival height of 3 mm, the healer with a height of 3.5 mm (UNITITE, CIMU 4535, SIN). The models used were: (G2H2,5-WS) 2mm gingival height, 2.5mm healing, without soft material; (G2H2,5-S2) 2mm gingival height, 2.5mm healing, with 2mm reline; (G2H2,5-S4) 2mm gingival height, 2.5mm healing, with 4mm reline; (G3H3,5-WS) gingival height of 3mm, healing of 3.5mm, without soft material; (G3H3,5-S2) 3mm gingival height, 3.5mm healing, and 2mm reline and (G3H3,5-S4) gingival height of 3mm, healing of 3.5mm and reliner of 4mm. The methodology for modeling was based on a surface scan of a complete lower denture assembled, under a standard lower model, and its seating model. The geometries of the implants (CM 3.5x10mm) and their healers were obtained by simplifying their design in the SolidWorks program and in the Rhinoceros 3D program. The software used for analysis was ANSYS 17.0. The visualization of the results was qualitative through displacement maps, von Mises and maximum principal stress. The regions with the greatest displacements were those of the most anterior implants (#33 and #43), and those of model 6 submitted to vertical forces presented the greatest displacements, close to 0.05 mm. The oblique force, in general, tended to place more stress on the implants on the side where the loads were applied. In the bone tissue, it was possible to observe that the cortical bone showed a higher concentration of tensile stress than the trabecular bone. The use of soft material generated lower tensions transmitted to the gingival tissue, concentrating these tensions mainly in the soft material. The non-use of soft material increases stress concentrations on implants/healers, regardless of their thickness or gingival thickness. It was concluded that the use of a soft reliner reduced the stresses on the implants/healers and gingival tissue; the increase in the thickness of the reline material did not influence the reduction of tensions to the supporting tissues and thicker gingival tissues were favorable in reducing the tensions transmitted to the bone tissue, but concentrated more tensions in the implants/healing agentes(AU)

Análise comparativa da influência de filtros de pós-processamento e da variação dos parâmetros de aquisição na quantificação de artefatos metálicos em imagens de tomografia computadorizada de feixe cônico / Comparative analysis of the influence of post-processing filters and the variation of acquisition parameters in the quantification of metallic artefacts in cone-beam computed tomography

Este estudo teve como objetivo comparar o efeito de 04 filtros de realce de imagem - Multi CDT NR1 e BAR1 - do software e-Vol DX (e-Vol DX, CDT, Brasil) e os filtros 1x e 2x do software Ondemand3D (CyberMed, Seoul, Republic of Korea), na quantificação de artefatos gerados por implantes dentários em imagens de tomografia computadorizada de feixe cônico (TCFC). Foram utilizadas imagens de TCFC de um phantom de mandíbula, adquiridas com variação do material do implante (titânio (Ti) e dióxido de zircônio (ZrO2)), região do implante (incisivo, canino, pré-molar e molar), tamanho do voxel (0,25 mm e 0,30mm) e posição do phantom no FOV (central, anterior, posterior, direita e esquerda). No software ImageJ em corte axial previamente definido, e usado como referência em cada um dos volumes estudados, em imagens com e sem a aplicação dos filtros, foi realizado a quantificação dos artefatos por um radiologista devidamente calibrado (ICC 0,97). Foram definidos grupos experimentais para as análises estatísticas das variáveis 02 a 02, sempre aliadas à variável filtro e seus efeitos na quantificação dos artefatos. Os testes de Shapiro-Wilk e de Bartlett, foram utilizados para avaliar a normalidade e homoscedasticidade. Para estudo das diferenças significativas entre os grupos foram utilizados os testes de ANOVA e Tukey (paramétricos), Kruskal-Wallis seguido de Conover-Iman (não paramétricos). Os resultados evidenciaram que o Ti apresentou menor quantificação em comparação ao ZrO2, nos 02 softwares. A menor quantificação de artefatos foi obtida no software e-Vol DX, filtro BAR 1, Ti e ZrO2. Não houve diferença significativa em relação ao tamanho do voxel para os materiais estudados (p=0,975 e p=0,901), posição do implante (p>0.05) e variações de posição no FOV (p>0.05). O Filtro Multi não apresentou diferenças significativas em relação às imagens sem filtro. Para os filtros do OnDemad3D, não houve diferença entre uso e não uso, independentemente do tamanho do voxel (p>0,05). Em conclusão o filtro BAR 1 apresentou-se como uma promissora ferramenta na redução dos artefatos oriundos de implantes dentários. (AU)

This study aimed to compare the effect of 04 image enhancement filters - Multi CDT NR1 and BAR1 - of the e-Vol DX software (e-Vol DX, CDT, Brazil) and the 1x and 2x filters of the Ondemand3D software (CyberMed, Seoul, Republic of Korea), in the quantification of artifacts generated by dental implants in cone beam computed tomography (CBCT) images. CBCT images of a mandible phantom were used, acquired with variation of the implant material (titanium (Ti) and zirconium dioxide (ZrO2)), implant region (incisor, canine, premolar and molar), voxel size (0.25 mm and 0.30 mm) and phantom position in the FOV (central, anterior, posterior, right and left). In the ImageJ software, in a previously defined axial section, and used as a reference in each of the volumes studied, in images with and without the application of filters, the quantification of the artifacts was performed by a properly calibrated radiologist (ICC 0.97). Experimental groups were defined for the statistical analysis of variables 02 to 02, always combined with the filter variable and its effects on the quantification of artifacts. The Shapiro-Wilk and Bartlett tests were used to assess normality and homoscedasticity. To study the significant differences between the groups, the ANOVA and Tukey tests (parametric), Kruskal-Wallis followed by Conover-Iman (non-parametric) were used. The results showed that Ti presented lower quantification compared to ZrO2, in the 02 softwares. The lowest quantification of artifacts was obtained using the e-Vol DX software, BAR 1, Ti and ZrO2 filters. There was no significant difference regarding voxel size for the materials studied (p=0.975 and p=0.901), implant position (p>0.05) and position variations in the FOV (p>0.05). The Multi Filter did not present significant differences in relation to the unfiltered images. For OnDemad3D filters, there was no difference between use and non-use, regardless of voxel size (p>0.05). In conclusion, the BAR 1 filter presented itself as a promising tool in the reduction of artifacts from dental implants (AU)

Avaliação do reparo ósseo peri-implantar em ratos tratados com quimioterapia e dose oncológica de zoledronato / Evaluation of peri-implant bone repair in rats treated with chemotherapy and oncological dose of zoledronate

O objetivo do presente estudo foi avaliar a influencia da terapia sistêmica com zoledronato, cisplatina, ou a associação das drogas, sobre o processo de reparo ósseo peri-implantar ao redor de implantes instalados em tíbias de ratos. Foram utilizados 80 ratos machos, com 6 meses de idade, pesando aproximadamente 450g. Os animais foram separados em 2 grandes grupos experimentais, grupo Tardio (TAR) e grupo Imediato (IME) e divididos nos seguintes subgrupos onde receberam os seguintes tratamentos: Grupo SAL-IME (n=10), Grupo SAL-TAR (n=10): duas injeções de 0,5 ml de solução salina a 0.9%; Grupo CIS-IME (n=10), Grupo CIS-TAR (n=10): uma injeção de Cisplatina (5mg/kg) e outra injeção de 0,5 ml de solução salina a 0.9%; Grupo ZOL-IME (n=10), Grupo ZOL-TAR (n=10): uma injeção 0,5 ml de solução salina a 0.9% e uma injeção de 100 µg/kg de zoledronato diluído 0,45 ml em solução de cloreto de sódio 0,9%; Grupo ZOL/CIS-IME (n=10), Grupo ZOL/CIS-TAR (n=10): uma injeção de Cisplatina (5mg/kg) e uma injeção de 100 µg/Kg de zoledronato diluído 0,45 ml em solução de cloreto de sódio 0,9%. A administação ocorreu por via intraperitoneal em um intervalo de três dias, durante oito semanas. Após 16 semanas do início do tratamento medicamentoso, os animais foram submetidos a instalação dos implantes nas tíbias direitas e esquerdas sob anestesia geral. Decorridos 16 semanas (grupo IME) e 24 semanas (grupo TAR) do início do tratamento medicamentoso, os animais foram submetidos à eutanásia pela administração de dose letal de thiopental (150mg/kg). As tíbias direitas e esquerdas foram coletadas e fixadas em formaldeído 4% e processadas de acordo com as análises propostas. A condição geral de saúde foi verificada durante todo o período experimental através do monitoramento do peso corporal e um minucioso exame clínico da região peri-implantar nas tíbias direita e esquerda foi realizado no momento das eutanásias. As tíbias selecionadas para análise histométrica do contato direto entre osso e implante foram processadas sem desmineralização. Os espécimes restantes foram submetidos ao processamento histológico convencional, constituído por desmineralização e inclusão em parafina. Foram realizadas secções semi seriadas de 4 µm de espessura em direção longitudinal à loja do implante, e os cortes histológicos foram selecionados e corados pelo método da Hematoxilina Eosina para as análises histopatológica dos tecidos peri-implantares e histométrica do tecido ósseo. Os dados obtidos foram submetidos à análise estatística (p≤0,05) em programa computacional especializado (Bioestat 5.0). Os animais pertencentes aos grupos CIS-IME e CIS-TAR, apresentram menor peso quando comparados aos demais grupos. O grupo ZOL-IME, ZOL-TAR, apresentaram maior porcentagem de tecido ósseo total (PTO-T) em comparação a CIS-IME e CIS-TAR, ZOL/CIS-IME e ZOL/CIS TAR apresentaram maior porcentagem de tecido ósseo não vital (PTO-NV) quando comparados aos demais grupos. Os grupos CIS-IME e CIS-TAR apresentarm menor contato osso/implante (COI) quando comparados aos demais grupos. Deste modo conclui se que, a associação desses medicamentos é um potencial fator de risco para desenvolvimento da osteonecrose dos maxilares e de acordo com as análises histopatológicas e de COI apresenta comprometimento mais severo aos tecidos peri-implantares(AU)

The aim of the present study was to evaluate the influence of systemic therapy with zoledronate, cisplatin, or the combination of drugs, on the peri-implant bone repair process around implants installed in rat tibiae. Eighty male rats, 6 months old, weighing approximately 450g, were used. The animals were separated into 2 large experimental groups, Late group (TAR) and Immediate group (IME) and divided into the following subgroups where they received the following treatments: SAL-IME Group (n = 10), SAL-TAR Group (n = 10 ): two injections of 0.5 ml of 0.9% saline; : CIS-IME Group (n = 10), CIS-TAR Group (n = 10): an injection of Cisplatin (5mg / kg) and another injection of 0.5 ml of 0.9% saline; ZOL-IME Group (n = 10), ZOL-TAR Group (n = 10): an injection of 0.5 ml of 0.9% saline and an injection of 100 µg / kg of zoledronate diluted 0.45 ml in solution of 0.9% sodium chloride; : ZOL / CIS-IME Group (n = 10), ZOL / CIS-TAR Group (n = 10): an injection of Cisplatin (5mg / kg) and an injection of 100 µg / kg of diluted zoledronate 0.45 ml in 0.9% sodium chloride solution. The administration took place intraperitoneally over an interval of three days, for eight weeks. After 16 weeks from the beginning of drug treatment, the animals were submitted to the implantation of implants in right and left tibiae under general anesthesia. After 16 weeks (IME group) and 24 weeks (TAR group) after the beginning of drug treatment, the animals were euthanized by the administration of a lethal dose of thiopental (150mg / kg). The right and left tibiae were collected and fixed in 4% formaldehyde and processed according to the proposed analyzes. The general health condition was verified throughout the experimental period by monitoring body weight and a thorough clinical examination of the peri-implant region in the right and left tibia was performed at the time of euthanasia. The tibiae selected for histometric analysis of the direct contact between bone and implant were processed without demineralization. The remaining specimens were submitted to conventional histological processing, consisting of demineralization and inclusion in paraffin. Semi-serial sections of 4 µm thick were made in the longitudinal direction to the implant store, and the histological sections were selected and stained by the Hematoxylin Eosin method for the histopathological analysis of the peri-implant tissues and histometric of the newly formed bone tissue. The data obtained were submitted to statistical analysis (p≤0.05) in a specialized computer program (Bioestat 5.0). The CISIME and CIS-TAR groups had less weight when compared to the other groups. The ZOL-IME group, ZOL-TAR, had higher PTO-T compared to CISIME and CIS-TAR, ZOL / CIS-IME and ZOL / CIS TAR had higher PTO-NV when compared to the other groups. The CIS-IME and CIS-TAR groups had lower bone implant contact (COI) when compared to the other groups. Thus, it is concluded that the combination of these drugs is a potential risk factor for the development of osteonecrosis of the jaws and, according to the histopathological and COI analyzes, it presents more severe impairment to the peri-implant tissues(AU)

Estudo experimental de implantes com superfície ativada pela tetraciclina: caracterização topográfica, histométrica, histoquímica e imunohistoquímica / Experimental study of implants with surface activated by tetracycline: topographic, histometric, histochemical and immunohistochemical characteristics

Modificações topográficas e físico-químicas da superfície dos implantes têm sido propostas para aumentar a porcentagem de contato osso-implante, principalmente em áreas de tecido ósseo de menor densidade, favorecer as respostas biológicas em um período de reparo mais curto e, consequentemente, favorecer o sucesso a longo prazo dos implantes osseointegráveis. O objetivo deste trabalho foi avaliar experimentalmente a modificação de superfície de implantes dentários pela adição de tetraciclina com avaliações pela Microscopia Eletrônica de Varredura (MEV), Energia Dispersiva de Raios X (EDS), medidas do ângulo de contato e processo de reparo peri-implantar pelo método imunohistomorfometrico. Foram utilizados quarenta e oito implantes (1,6mm de diâmetro e 4,0 mm de comprimento) e 6 discos de titânio (6mm de diâmetro e 1,5 mm de espessura) divididos em dois grupos: Grupo Tratamento Ácido (GA) e Grupo Tratamento Tetraciclina (GT). Para análise topográfica utilizou seis implantes com distribuição igual entre os grupos. Para a análise de rugosidade utilizou-se os 6 discos de titânio com distribuição igual entre os grupos. Para os testes em animais foram utilizados 42 implantes e 42 ratos Wistar igualmente divididos em dois grupos com implantes instalados na tíbia e divididos em três períodos experimentais: 7,30 e 60 dias. Os espécimes foram processados para avaliação histológica e imunoistoquímica. Resultados: A topografia de superfície revelou que GA apresentava microcavidades de rugosidade homogênea, sem contaminação da superfície e com picos de titânio e oxigênio. GT apresentou superfície mais homogênea e regular quando comparado GA, também revelou picos de titânio e oxigênio predominantemente, com presença de discretos picos correspondentes aos elementos cálcio (Ca), fósforo (P), Carbono (C) e Magnésio. GA não apresentou molhamento enquanto GT apresentou um molhamento parcial. Comparando os valores das porcentagens da extensão de tecido ósseo em contato com a superfície do implante (BIC) e a área ocupada por tecido ósseo nas três primeiras roscas do implante (BAFO) apenas em 30 dias apresentou diferença estatística significativa (p< 0,05). Os resultados imunohistomorfométricos apontam para a elevada sequência dinâmica dos processos biológicos de reparo nos primeiros 30 dias após a inserção do implante em ambos os grupos, tendendo ao equilíbrio aos 60 dias. Conclusão A superfície ativada pela tetraciclina se mostrou biocompatível, com ausência de reações inflamatórias junto ao tecido peri-implantar e uma ossificação adequada, sendo qualitativamente e quantitativamente superior ao grupo controle, sugerindo uma osseointegração precoce(AU)

Topographic and physical-chemical modifications of the surface of the implants have been proposed to increase the percentage of bone-implant contact, especially in areas of lower density bone tissue, favor biological responses in a shorter repair period and, consequently, favor the long-term success of osseointegrated implants. The objective of this work was to experimentally evaluate the surface modification of dental implants by adding tetracycline with evaluations by Scanning Electron Microscopy (SEM), X-ray Dispersive Energy (EDS), contact angle measurements and peri-implant repair process by the immunohistomorphometric method. Forty-eight implants (1.6 mm in diameter and 4.0 mm in length) and 6 titanium discs (6 mm in diameter and 1.5 mm in thickness) were used, divided into two groups: Acid Treatment Group (GA) and Group Tetracycline treatment (GT). For topographic analysis, six implants were used with equal distribution between groups. For the roughness analysis, the 6 titanium discs were used with equal distribution between the groups. For the animal tests, 42 implants and 42 Wistar rats were equally divided into two groups with implants installed in the tibia and divided into three experimental periods: 7, 30 and 60 days. The specimens were processed for histological and immunohistochemical evaluation. Results: The surface topography revealed that GA had homogeneous roughness microcavities, without surface contamination and with titanium and oxygen peaks. GT showed a more homogeneous and regular surface when compared to GA, it also revealed titanium and oxygen peaks predominantly, with the presence of discrete peaks corresponding to the elements calcium (Ca), phosphorus (P), carbon (C) and magnesium. GA showed no wetting while GT showed partial wetting. Comparing the values of the percentages of bone tissue extension in contact with the implant surface (BIC) and the area occupied by bone tissue in the first three implant threads (BAFO) in only 30 days, there was a statistically significant difference (p < 0.05). The immunohistomorphometric results point to the high dynamic sequence of biological repair processes in the first 30 days after insertion of the implant in both groups, tending to balance at 60 days. Conclusion The surface activated by tetracycline proved to be biocompatible, with no inflammatory reactions close to the peri-implant tissue and adequate ossification, being qualitatively and quantitatively superior to the control group, suggesting early osseointegration(AU)

Caracterização do tecido ósseo peri-implantar frente ao uso do óxido nítrico para funcionalização da superfície de implantes instalados na maxila de ratas induzidas à deficiência de estrógeno e síndrome metabólica tratadas com risedronato de sódio / Characterization of peri-implant bone tissue against the use of nitric oxide for surface functionalization of implants installed in the maxilla of rats induced to estrogen deficiency and metabolic syndrome treated with risedronate sodium

Objetivo: caracterizar o processo de reparo ósseo peri-implantar em maxilas de ratas ovariectomizadas com síndrome metabólica induzida por dieta de cafeteria, tratadas com risedronato e instalação de implantes funcionalizados com [Ru(terpy)(bdq)NO]3+ (TERPY). Materiais e métodos: os testes in vitro realizados na Fase 1 avaliou as propriedades biológicas e físico-químicas da melhor concentração da TERPY frente às respostas osteogênicas, para a funcionalização dos implantes pela técnica de LbL. A realização de experimentos in vivo na Fase 2 avaliou o efeito da superfície funcionalizada durante o reparo ósseo peri-implantar. Para isso, 48 ratas Wistar foram divididas em: SHAM CONV (n=8), OVX SM CONV (n=8), OVX SM RIS CONV (n=8), SHAM TERPY (n=8), OVX SM TERPY (n=8) e OVX SM RIS TERPY (n=8). Em t=0, as ratas foram submetidas à cirurgia fictícia (SHAM) e à cirurgia de ovariectomia bilateral (OVX); após a recuperação da cirurgia, os animais receberam a dieta de cafeteria (SM). Passados 30 dias (t=30), o tratamento medicamentoso com risedronato de sódio (0,7 mg/kg/semana) (RIS) ou solução salina (0,3 ml), via gavagem, foi iniciado e realizado até o momento da eutanásia. Sessenta dias após o início do tratamento medicamentoso (t=90), a cirurgia de exodontia do primeiro molar superior foi realizada junto à instalação imediata dos implantes de forma bilateral (CONV ou TERPY). Quatorze dias após a cirurgia de instalação dos implantes (t=104), todos os grupos experimentais receberam a injeção intramuscular do fluorocromo calceína (20 mg/kg) e após 10 dias (t=114), do fluorocromo vermelho de alizarina (25 mg/kg). Aos 28 dias pós-operatórios (dia da eutanásia, t=118), os animais foram anestesiados e, nas maxilas do lado direito, os implantes foram submetidos ao torque reverso e imediatamente após a remoção dos implantes, foi realizada a coleta do tecido ósseo para análise de PCR tempo real para avaliação da expressão relativa de ALP, iBSP, OCN, OPG, RANKL, TRAP e VEGF, seguido da eutanásia dos animais; as maxilas do lado esquerdo foram coletadas para a análise de Micro-CT (BV/TV, Tb.Th, Tb.N, Tb.Sp e i.S) e, após o escaneamento, as mesmas passaram pelo processamento para análise da dinâmica óssea por fluorocromos (MAR e ELCOI). Os dados foram submetidos à análise estatística, com o nível de significância de 5% (p<0,05). Resultados: Fase 1: poucas diferenças foram observadas entre as duas concentrações avaliadas e assim, a menor concentração do fármaco foi selecionada (10µM). Fase 2: os implantes funcionalizados com a TERPY apresentaram os maiores valores absolutos de torque de remoção para todos os grupos e com diferença estatística para OVX SM TERPY (p=0,0402). A associação sistêmica entre o risedronato e a TERPY em ratas ovariectomizadas (OVX SM RIS TERPY) demonstrou expressão aumentada para iBSP e equilíbrio entre OPG e RANKL, corroborando com os dados obtidos para MAR (p=0,0052) e com os parâmetros de BV/TV, Tb.Th e i.S da análise microtomográfica para esse mesmo grupo. Conclusão: o desempenho clínico dos implantes funcionalizados com TERPY foi favorável, e, quando associado à administração sistêmica de risedronato de sódio, os resultados se tornam mais promissores(AU)

Objective: characterize the peri-implant bone tissue repair process in maxilla of ovariectomized rats with metabolic syndrome induced by cafeteria diet, treated with risedronate and through placement the implants functionalized with [Ru(terpy)(bdq)NO]3+ (TERY). Materials and methods: in vitro tests performed in Phase 1 evaluated the biological and physicochemical properties of the better concentration of TERPY against osteogenic responses, for the functionalization of implants using the LbL technique. In vivo experiments in Phase 2 evaluated the effect of functionalized surface during peri-implant bone repair. For this, 48 female rats were divided: SHAM CONV (n=8), OVX SM CONV (n=8), OVX SM RIS CONV (n=8), SHAM TERPY (n=8), OVX SM TERPY (n=8) and OVX SM RIS TERPY (n=8). At t=0, the rats underwent unreal surgery (SHAM) and bilateral ovariectomy surgery (OVX); after recovery from surgery, animals received cafeteria diet (SM). After 30 days (t=30), drug treatment with risedronate sodium (0.7 mg/kg/week) (RIS) or saline solution (0.3 ml), via gavage, was started and sustained out until the time of euthanasia. Sixty days after the start of drug treatment (t=90), the maxillary first molar extraction surgery was performed followed by the immediate installation of the implants bilaterally (CONV or TERPY). Fourteen days after implant placement surgery (t=104), all experimental groups received intramuscular injection of the fluorochrome calcein (20 mg/kg) and after 10 days (t=114), the red fluorochrome alizarin (25 mg/kg). After 28 postoperative days (day of euthanasia, t=118), the animals were anesthetized and, in the maxillary on the right side, the implants were subjected to reverse torque and immediately after removal of the implants, bone tissue was collected for real-time PCR analysis to measure the relative expression of ALP, iBSP, OCN, OPG, RANKL, TRAP e VEGF, followed by euthanasia of animals; the left side maxillary were collected for Micro-CT analysis (BV/TV, Tb.Th, Tb.N, Tb.Sp e i.S) and, after scanning, they underwent processing for analysis of bone dynamics by fluorochromes (MAR and ELCOI). Data values were subjected to statistical analysis, with a significance level of 5% (p<0.05). Results: Phase 1: few differences were observed between the two concentrations evaluated and thus, the lowest drug concentration was selected (10µM). Phase 2: the implants functionalized with TERPY presented the highest absolute values of removal torque for all groups and with statistical difference for OVX SM TERPY (p=0.0402). The systemic association between risedronate and TERPY in ovariectomized rats (OVX SM RIS TERPY) showed increased expression for iBSP and balance between OPG and RANKL, corroborating the data obtained for MAR (p=0.0052) and with the parameters BV/TV, Tb.Th and i.S of the microtomographic analysis for this same group. Conclusion: the clinical performance of implants functionalized with TERPY was favorable, and when associated with the systemic administration of risedronate sodium, the results become more promising(AU)

Homogenous Bone Grafts as an Alternative in Oral Rehabilitation Treatments with Dental Implants / Los Injertos Óseos Homogéneos como una Alternativa en los Tratamientos de Rehabilitación Oral con Implantes Dentales

ABSTRACT: The present study aims to describe, through a case report, the functioning of bone grafts, where they are obtained including bone banks and the different dental areas in which it is used. A 50-year.old female patient HMR, sought the postgraduate college of dentistry CECAPE for oral rehabilitation. The initial clinical examination revealed the absence of several dental elements in both the maxilla and mandi ble, bone resorption in the entire maxillary extension where there was an absence of elements in the anterior region and the presence of a torus in the palatal region. Initial tomographic examinations of the maxilla and mandible were performed, looking for the best conduct regarding the diagnosis and planning of the case. After the clinical and radiographic examinations was performed, and the diagnosis was reached, it was determined as a treatment for oral rehabilitation of the maxilla, bone grafting and an Implant-supported Removable Partial Prosthesis and for the mandible a Dento-muco-supported Removable Partial Prosthesis. Dental treatments and oral rehabilitation from the use of bone tissues and bone grafting have become commonly used. Procedures that would normally lead to failure started to increase the percentage of successes due to the use of these biomaterials. The use of bone grafts in dentistry has been shown to be a very effective and useful resource, considering its great applicability in bone reconstructions in different areas of dentistry.

RESUMEN: El presente estudio tiene como objetivo describir a través de un informe de caso, el funcionamiento de los injertos óseos, donde se obtienen, incluidos los bancos de huesos y las diferentes áreas dentales en las que se emplea. Una paciente HMR, de 50 años de edad, asistió el centro universitario de posgrado CECAPE para rehabilitación oral. El examen clínico inicial reveló la ausencia de varios dientes tanto en el maxilar como en la mandíbula, la resorción ósea en toda la extensión maxilar donde había ausencia de dientes en la región anterior y la presencia de un torus en la región palatina. Se realizaron exámenes tomográficos iniciales del maxilar y mandíbula, buscando la mejor conducta con respecto al diagnóstico y la planificación del caso. Después de los exámenes clínicos y radiográficos realizados y el diagnóstico listo, se determinó como un tratamiento para la rehabilitación oral del maxilar, el injerto óseo y una prótesis removible implantosoportada y para la mandíbula una prótesis parcial removible dento-muco-soportada. Los tratamientos dentales y la rehabilitación oral a partir del uso de tejidos óseos y el injerto óseo se han utilizado comúnmente. Los procedimientos que normalmente conducirían al fracaso comenzaron a aumentar el porcentaje de éxitos debido al uso de estos biomateriales. Se ha demostrado que el uso de injertos óseos en odontología es un recurso muy eficaz y útil, considerando su gran aplicabilidad en las reconstrucciones óseas en diferentes áreas de la odontología.

Análise microtomografica e imunoistoquímica do osso peri-implantar em dimorfismo sexual com implantes funcionalizados com estrôncio / Microtomographic and immunohistochemical analysis of periimplant bone in sexual dimorphism with strontium functionalized implants

O presente trabalho tem por objetivo caracterizar a influência de esteróides gonadais e o dimorfismo sexual na microarquitetura do tecido ósseo formado ao redor de implantes funcionalizados por estrôncio e instalados na tíbia de ratos e ratas que foram divididos em 4 grupos experimentais. Os grupos SHAM F e SHAM M foram os grupos controle, submetidos a cirurgia fictícia, nas fêmeas e machos. O grupo OVX foram as fêmeas submetidas à cirurgia de ovariectomia bilateral e os ORQ foram os machos submetidos à orquiectomia. Após 30 dias das cirurgias para remoção das gônadas ou cirurgias fictícias, os animais foram submetidos à instalação dos implantes nas tíbias, cada animal recebeu 2 implantes, sendo 1 em cada metáfise tibial. A eutanásia foi realizada aos 60 dias após a instalação dos implantes. Os ossos tibiais foram coletados e processados laboratorialmente para a análise tridimensional através da avaliação microtomográfica (Micro-Ct), também foi realizada uma análise imunoistoquímica, com objetivo de analisar as respostas celulares quanto ao processo de reabsorção óssea, remodelação e mineralização. Concluiu-se que a funcionalização com estrôncio na superfície dos implantes interferiu no processo de reparo perimplantar, resultando em tecido ósseo com diferentes características microarquiteturais, de acordo com o gênero(AU)

The present work aims to characterize the influence of gonadal steroids and sexual dimorphism on the microarchitecture of bone tissue formed around strontium functionalized implants and installed in the tibia of rats and mice that were divided into 4 experimental groups. The SHAM F and SHAM M groups were the control groups, applying the fictitious surgery, in the latter and males. The OVX group were as submitted to bilateral ovariectomy surgery and the ORQ were the males related to the orchiectomy. After 30 days of surgery to remove the gonads or fictitious surgeries, the animals were infected by installing the implants in the tibiae, each animal completes 2 implants, 1 in each tibial metaphysis. Euthanasia performed 60 days after the implant installation. Tibial bones were collected and processed in the laboratory for a three-dimensional analysis through microtomographic evaluation (Micro-Ct), an immunohistochemical analysis was also carried out, with the objective of analyzing cellular responses regarding the process of bone resorption, remodeling and mineralization. It was concluded that strontium functionalization on the surface of the implants interfered in the process of perimplant repair, termination in bone tissue with different microarchitectural characteristics, according to gender(AU)

The impact of maintenance on peri-implant health

Abstract Most of the literature evaluating dental implants focuses on implant survival, which is a limited proxy for the successful rehabilitation of patients with missing teeth. Success should include not only survival but also lack of mechanical, biological, and esthetics problems. A comprehensive review of local and systemic risk factors prior to implant placement will allow the tailoring of treatment planning and maintenance protocols to the patient's profile in order to achieve longitudinal success of the therapy. This review discusses the role of controlling different risk factors and prevention/treatment of peri-implant mucositis in order to avoid peri-implantitis. Although the literature addressing the topic is still scarce, the existing evidence shows that performing optimal plaque control and regular visits to the dentist seem to be adequate to prevent peri-implant lesions. Due to impossibility of defining a probing depth associate with peri-implant health, radiographic evaluations may be considered in the daily practice. So far, there is a strong evidence linking a past history of periodontal disease to peri-implant lesions, but this is not so evident for other factors including smoking and diabetes. The prevention of biological complications starts even before implant placement and include a broader analysis of the patient risk profile and tailoring the rehabilitation and maintenance protocols accordingly. It should be highlighted that the installation of implants does not modify the patient profile, since it does not modify genetics, microbiology or behavioral habits of any individual.

Treatment of peri-implant soft tissue defects: a narrative review

Abstract Soft tissue defects around dental implants, such as papilla or volume loss, peri-implant recession and alterations of the ridge color and/or texture, lead to esthetic and functional complaints. Treatments of these defects in implants are more demanding than in teeth because peri-implant tissue exhibits different anatomical and histological characteristics. This narrative review discusses the proposed treatments for soft tissue defects around implants in the current literature. Several clinical and pre-clinical studies addressed methods to augment the quantity of the peri-implant keratinized mucosa. Autogenous grafts performed better than soft tissue substitutes in the treatment of soft tissue defects, but there is no clinical consensus on the more appropriate donor area for connective tissue grafts. Treatment for facial volume loss, alterations on the mucosa color or texture and shallow peri-implant recessions are more predictable than deep recessions and sites that present loss of papilla. Correction of peri-implant soft tissue defects may be challenging, especially in areas that exhibit larger defects and interproximal loss. Therefore, the regeneration of soft and hard tissues during implant treatment is important to prevent the occurrence of these alterations.

Bone healing dynamics associated with 3 implants with different surfaces: histologic and histomorphometric analyses in dogs

PURPOSE: This study evaluated differences in bone healing and remodeling among 3 implants with different surfaces: sandblasting and large-grit acid etching (SLA; IS-III Active®), SLA with hydroxyapatite nanocoating (IS-III Bioactive®), and SLA stored in sodium chloride solution (SLActive®). METHODS: The mandibular second, third, and fourth premolars of 9 dogs were extracted. After 4 weeks, 9 dogs with edentulous alveolar ridges underwent surgical placement of 3 implants bilaterally and were allowed to heal for 2, 4, or 12 weeks. Histologic and histomorphometric analyses were performed on 54 stained slides based on the following parameters: vertical marginal bone loss at the buccal and lingual aspects of the implant (b-MBL and l-MBL, respectively), mineralized bone-to-implant contact (mBIC), osteoid-to-implant contact (OIC), total bone-to-implant contact (tBIC), mineralized bone area fraction occupied (mBAFO), osteoid area fraction occupied (OAFO), and total bone area fraction occupied (tBAFO) in the threads of the region of interest. Two-way analysis of variance (3 types of implant surface×3 healing time periods) and additional analyses for simple effects were performed. RESULTS: Statistically significant differences were observed across the implant surfaces for OIC, mBIC, tBIC, OAFO, and tBAFO. Statistically significant differences were observed over time for l-MBL, mBIC, tBIC, mBAFO, and tBAFO. In addition, an interaction effect between the implant surface and the healing time period was observed for mBIC, tBIC, and mBAFO. CONCLUSIONS: Our results suggest that implant surface wettability facilitates bone healing dynamics, which could be attributed to the improvement of early osseointegration. In addition, osteoblasts might become more activated with the use of HA-coated surface implants than with hydrophobic surface implants in the remodeling phase.

Bankart lesion repair: biomechanical and anatomical analysis of Mason-Allen and simple sutures in a swine model / Reparo da lesão de Bankart: análise biomecânica e anatômica das suturas tipo Mason-Allen e simples em modelo suíno

ABSTRACT Objective: To evaluate the labral height and pullout resistance after the repair of Bankart lesions in the glenohumeral joint of swine models, using double-loaded anchors with two suture configurations: simple and Mason-Allen. Methods: Ten swine shoulders were used, in which Bankart lesions were created. For each specimen, the lesion was sutured randomly with Mason-Allen sutures or simple sutures. The labral height was measured before the lesion was created and after the labral repair. The specimens were submitted to a tensile test for biomechanical evaluation. Results: In specimens submitted to simple suture (n = 5), the mean labral height observed before the lesion was 3.86 mm, and after suturing, 3.33 mm. In specimens submitted to Mason-Allen suture (n = 5), it was observed that the mean labral height before the lesion was 3.92 mm, and after suturing, 3.48 mm. When comparing the labral height after simple suture and Mason-Allen suture, no significant difference was observed. The pullout force at the end of the tensile test on specimens with single suture was 130 N, and in specimens with Mason-Allen suture, 128.6 N. No statistically significant differences were observed between the shoulders treated with single suture and Mason-Allen suture; p = 0.885. Conclusions: Repair of Bankart lesions with Mason-Allen suture provides increased labrum height; however, it does not increase the pullout strength.

RESUMO Objetivo: Avaliar a altura labral e a resistência ao arrancamento do reparo da lesão de Bankart em articulação glenoumeral de suínos, com âncoras duplamente carregadas com duas configurações de sutura: simples e tipo Mason-Allen. Métodos: Foram usados dez ombros suínos, nos quais foram criadas as lesões de Bankart. Para cada espécime foi feita a sutura da lesão com suturas tipo Mason-Allen e simples de forma aleatória. A altura labral foi mensurada previamente à confecção da lesão e após o reparo labral. Os espécimes foram submetidos ao ensaio de tração para avaliação biomecânica. Resultados: Nos espécimes submetidos a sutura simples (n = 5), observou-se altura média previamente à confecção da lesão de 3,86 mm e após a sutura, de 3,33 mm. Nos espécimes submetidos a sutura Mason-Allen (n = 5), observou-se que a altura média previamente à confecção da lesão era de 3,92 mm e após a sutura, de 3,48 mm. Ao comparar a altura labral após a sutura simples e Mason-Allen, não foram observadas diferenças significantes. A força de arrancamento no fim do ensaio de tração nos espécimes com sutura simples foi de 130 N e nos espécimes com sutura Mason-Allen, 128,6 N. Não houve diferença estatisticamente significante entre os ombros com suturas simples e Mason-Allen, p = 0,885. Conclusões: O reparo das lesões de Bankart com sutura Mason-Allen proporciona aumento da altura do labrum, mas não eleva a força de resistência ao arrancamento.

Evaluation of Maxillary Sinus Septa Prior to Dental Implant Therapy: A Cone Beam Computed Tomography Study / Evaluación del Septo del Seno Maxilar Antes del Tratamiento con Implantes Dentales: Un Estudio con Tomografía Computarizada de Haz Cónico

SUMMARY: The objective of this study was to investigate the prevalence and location of maxillary sinus septa prior to dental implant therapy in different age groups by cone beam computed tomography (CBCT) and identify the most helpful orthogonal plane for this purpose. CBCT scans of 200 patients were selected. The final sample was divided into four groups according to age: (1) 30-39 y.o.; (2) 40-49 y.o.; (3) 50-59 y.o.; (4) +60 y.o. Three calibrated examiners assessed the presence and location (anterior, middle, posterior) of sinus septa using all orthogonal slices. The prevalence of septa per region and plane was compared by chi-square test. Among 359 maxillary sinuses evaluated, it was observed at least one septum in 163 sinuses (45.4 %). Overall, the anterior region was the most prevalent. However, when the age groups were considered, the anterior region was only the most prevalent in groups 2 and 3. The middle and posterior regions were more prevalent in groups 4 and 1, respectively. In conclusion, the prevalence of maxillary sinus septa in patients who were candidate to dental implant therapy was notably high. It was observed that the anterior region of the sinus was the most prevalent and the axial slice was the most representative.

RESUMEN: El objetivo de este estudio fue investigar la prevalencia y localización del septo del seno maxilar antes del tratamiento con implantes dentales en diferentes grupos etarios, por medio de la Tomografía Computarizada de Haz Cónico (TCHC). Fueron seleccionadas TCHC de 200 pacientes. La muestra final fue dividida en cuatro grupos de acuerdo con la edad: (1) 30-39 años; (2) 40-49 años; (3) 50-59 años y (4) +60 años. Tres examinadores calibrados evaluaron la presencia y localización (anterior, media o posterior) del septo del seno maxilar usando todas las secciones ortogonales. La prevalencia del septo por región y plano fue comparada mediante el test x-cuadrado. Entre los 359 senos maxilares evaluados, fue observado por lo menos un septo en 163 senos (45,4 %). Generalmente la región anterior fue la más prevalente. Sin embargo, cuando fueron considerados los grupos etarios, solamente la región anterior fue la más prevalente en los grupos 2 y 3. Las regiones media y posterior fueron las más prevalente en los grupos 4 y 1, respectivamente. La prevalencia del septo del seno maxilar en pacientes que son candidatos a tratamiento con implantes dentales fue notablemente alta. Se observó que la región anterior fue la más prevalente siendo las secciones axiales las más representativas.

The effects of subcutaneous injection of nicotine on osseointegration of machined and anodized implants in rabbits

Abstract Purpose: To evaluate the influence of subcutaneous injection nicotine in osseointegration process on different implant surfaces. Methods: Twenty-two male rabbits were distributed into two groups according to the subcutaneous injections: (1) nicotine 3 mg/day/kg and (2) 0.9 % NaCI 3 mL/day/kg, three times a day; subgroups were then designated-machined and anodized implants were placed in the right and left tibia bones, respectively. The animals were submitted euthanasia after periods of eight weeks to determine nicotine and cotinine levels, alkaline phosphatase and biomechanical analysis. Results: The plasmatic levels of nicotine and cotinine were 0.5 ± 0.28 ng/mL and 9.5 ± 6.51 ng/mL, respectively. The alkaline phosphatase analyses in blood levels in control group were observed 40.8 ± 11.88 UI/L and 40.75 ± 12.46 UI/L, for the surfaces machined and anodized, respectively. In the test group was observed levels 37.9 ± 4.84 UI/L, for both implant surfaces. No significant differences were observed between control and test groups and between the implant surfaces regarding alkaline phosphatase blood levels. For biomechanics, no significant differences were observed in control group between the machined (25±8.46 Ncm) or anodized (31.2 ± 6.76 Ncm) implants. However, the treatment with nicotine induced higher torque than control in both machined (38.3 ± 13.52 Ncm) and anodized (35.5 ± 14.17 Ncm) implants, with p = 0.0024 and p = 0.0121, respectively. Conclusion: Subcutaneous injection of nicotine following implant insertion didn't have effect on osseointegration, independently from the implant surface.

Effect of implant number and height on the biomechanics of full arch prosthesis

Aim: The goal of this study was to clarify the stress distribution in a full arch prosthesis according to the implant number and height in order to guide the clinical choice during planning. Methods: A computational analysis was performed to analyze the stress distribution in implants and bone tissue according to implant number (3, 4 or 5) and height (5, 8, 11 mm). A model of a jaw with polyurethane properties to simulate bone tissue was created through the Rhinoceros software (version 5.0 SR8, McNeel North America, Seattle, WA, USA). The titanium bar was fixed to the implant through a retention screw. The final geometry was exported in STEP format to ANSYS (ANSYS 15.0, ANSYS Inc., Houston, USA) and all materials were considered homogeneous, isotropic and linearly elastic. To assess distribution of stress forces, an axial load (200 N) was applied on the cantilever. Results in Von-Mises stress and strain criteria's were obtained for implants and bone, respectively. Qualitative and quantitative evaluations were performed. Results: The implant number and height influenced the prosthesis biomechanics, with more von-Mises stress and bone strain concentration for combination of 3 implants with 5 mm. Conclusion: It was concluded that higer length and more quantity of implant supporting a full arch prosthesis promoted less stress concentration during the simulated load. Decreasing the number of implants in rehabilitation is more harmful than decreasing their length for the stress and strain distribution

Oral implant osseointegration model in C57Bl/6 mice: microtomographic, histological, histomorphometric and molecular characterization

Abstract Despite the successful clinical application of titanium (Ti) as a biomaterial, the exact cellular and molecular mechanisms responsible for Ti osseointegration remains unclear, especially because of the limited methodological tools available in this field. Objective: In this study, we present a microscopic and molecular characterization of an oral implant osseointegration model using C57Bl/6 mice. Material and Methods: Forty-eight male wild-type mice received a Ti implant on the edentulous alveolar crest and the peri-implant sites were evaluated through microscopic (μCT, histological and birefringence) and molecular (RealTimePCRarray) analysis in different points in time after surgery (3, 7, 14 and 21 days). Results: The early stages of osseointegration were marked by an increased expression of growth factors and MSC markers. Subsequently, a provisional granulation tissue was formed, with high expression of VEGFb and earlier osteogenic markers (BMPs, ALP and Runx2). The immune/inflammatory phase was evidenced by an increased density of inflammatory cells, and high expression of cytokines (TNF, IL6, IL1) chemokines (CXCL3, CCL2, CCL5 and CXC3CL1) and chemokine receptors (CCR2 and CCR5). Also, iNOS expression remained low, while ARG1 was upregulated, indicating predominance of a M2-type response. At later points in time, the bone matrix density and volume were increased, in agreement with a high expression of Col1a1 and Col21a2. The remodelling process was marked by peaks of MMPs, RANKL and OPG expression at 14 days, and an increased density of osteoclasts. At 21 days, intimate Ti/bone contact was observed, with expression of final osteoblast differentiation markers (PHEX, SOST), as well as red spectrum collagen fibers. Conclusions: This study demonstrated a unique molecular view of oral osseointegration kinetics in C57Bl/6 mice, evidencing potential elements responsible for orchestrating cell migration, proliferation, ECM deposition and maturation, angiogenesis, bone formation and remodeling at the bone-implant interface in parallel with a novel microscopic analysis.

Daily melatonin administration improves osseointegration in pinealectomized rats

Abstract The hypothesis of this study was that the peri-implant bone healing of the group of pinealectomized rats would differ from the control group. The samples were subjected to immunohistochemical, microtomographic (total porosity and connectivity density), and fluorochrome (mineralized surface) analyses. Objectives The goal of this study was to investigate the cellular changes and bone remodeling dynamics along the bone/implant interface in pinealectomized rats. Material and Methods The total of 18 adult male rats (Rattus norvegicus albinus, Wistar) was divided into three groups (n=6): control (CO), pinealectomized without melatonin (PNX) and pinealectomized with melatonin (PNXm). All animals were submitted to the first surgery (pinealectomy), except the CO group. Thirty days after the pinealectomy without melatonin, the second surgery was conducted, in which all animals received an implant in each tibia (36 titanium implants with surface treatment were installed - Implalife® São Paulo, SP, Brazil). By gavage, the rats of the PNX group received the vehicle solution, and the procedure. Results Immunohistochemical analysis for runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OP) and osteocalcin (OC) showed that the bone repair process in the PNXm group was similar to that of the CO group, whereas the PNX group showed a delay. The microtomographic parameters of total porosity [Po(tot)] and bone surface (BS) showed no statistically significant differences, whereas for the connective density (Conn.Dn) a statistical difference was found between the CO and PNXm groups. Fluorochrome analysis of the active mineralized surface showed statistically significant difference between the CO and PNX and between the CO and PNXm groups. Conclusion The absence of the pineal gland impaired the bone repair process during osseointegration, however the daily melatonin replacement was able to restore this response.

Effects of hyperbaric oxygen treatment on implant osseointegration in experimental diabetes mellitus

Abstract Objective To evaluate whether hyperbaric oxygen (HBO) treatment has a favorable effect on implant osseointegration in diabetic rabbits. Material and Methods An experimental diabetes model was induced in 32 New Zealand rabbits through IV injection of alloxan. After the state of diabetes had been confirmed, one dental implant was placed in the metaphysical region of each animal's tibia. After the implants' placements, the animals were divided into two groups. Half of the animals underwent HBO treatment, while the other group did not receive HBO treatment and served as the control group. The animals were euthanized at the 4th and 8th weeks. The osseointegration of the implants were compared by histomorphometry and resonance frequency analysis (RFA). Results The Bone Implant Contact (BIC) values were significantly higher in the HBO group than in the control group at the 4th week. There was no difference in the BIC values between the groups at the 8th week. There was no significant difference in the RFA scores between the groups both at the 4th and 8th weeks after the operation. Conclusion Histomorphometry findings suggest that HBO has positive effect on implant osseointegration in the early healing period in diabetic rabbits. However, implant stability is not affected by HBO treatment.

A comparison of different bone graft materials in peri-implant guided bone regeneration

Abstract The aim of this study was to compare the effects of hydroxyapatite (HA), deproteinized bovine bone (DPB), human-derived allogenic bone (HALG), and calcium sulfate (CAP) graft biomaterials used with titanium barriers for bone augmentation to treat peri-implant defects in rat calvarium treated by guided bone regeneration (GBR). Thirty-two female Sprague-Dawley rats were divided into four groups: DPB, HALG, HA, and CAP. One titanium barrier was fixed to each rat's calvarium after the titanium implants had been fixed. In total, 32 titanium implants and barriers were used. Ninety days after the surgical procedure, all the barriers were removed. After decalcification of bone tissue, the titanium implants were removed gently, and new bone regeneration in the peri-implant area was analyzed histologically. Immunohistochemical staining of vascular endothelial growth factor (VEGF) was also performed. There were no statistically significant between-group differences in new bone regeneration or VEGF expression after 3 months. According to the results of the histological and immunohistochemical analyses, none of the grafts used in this study showed superiority with respect to new bone formation.