Comparison of removal torque of dual-acid etched and single-acid etched implants in rabbit tibias / 대한치과보철학회지

PURPOSE: Chemically strong-acids (HF and HCl/H₂SO₄) dual etching implant surfaces have higher strengths of osseointegration than machined implant surfaces. However, the dual acid treatment deteriorates the physical properties of the titanium by weakening the fatigue resistance of the implant and causing microcracks. The removal torque comparison between the dual-acid etched (hydrochloric acid, sulfuric acid, HS) and single-acid etched implants (hydrochloric acid, H) could reveal the efficiency of implant surface acid treatment. MATERIALS AND METHODS: Nine 3.75 × 4 mm dual-acid etched SLA implants and nine single-acid etched SLA implants were inserted into New Zealand rabbit tibias. After 10 days, removal torque, roughness, and wetting angle were measured. RESULTS: Mean removal torque values were as follows: Mean removal torque were 9.94 Ncm for HS group and 9.96 Ncm for H group (P=.995). Mean surface roughness value were 0.93 µm for HS group and 0.84 µm for H group (P=.170). Root mean square roughness (RSq) values were 1.21 µm for HS group and 1.08 µm for H group (P=.294), and mean wetting angle values were 99° for HS group and 98° for H group (P=.829). Statistical analysis showed no significant difference between the removal torques, roughness, or wetting angles of the two groups. CONCLUSION: In this experiment, we found no significant difference in removal torque, roughness, or wetting angle between dual-acid etched and single-acid etched implants.

Morfologia de implantes dentários com superfície tratada a laser: análise in vivo / Morphology of laser-treated dental implant surfaces: in vivo analysis

Rugosidades criadas em superfícies de implantes de titânio promovem alterações morfológicas que podem favorecer o contato osso/implante. A energia superficial resultante de jateamento com partículas, ataque químico e tratamento por oxidação anódica na superfície dos implantes promove mudanças na resposta das células ósseas. O objetivo deste estudo foi avaliar a resposta do tecido ósseo na superfície de implantes tratados sob irradiação a laser (Nd: YAG). Os implantes submetidos a este método foram analisados sob microscopia eletrônica de varredura (MEV) e confocal 3D, além de avaliação superficial por equipamento de rugosímetro. Foram instalados, em fêmures de ratos Wistar, 30 mini-implantes com tratamento superficial a laser, e confeccionados em titânio grau II. Os animais foram divididos em três grupos, de acordo com os períodos de reparação óssea – 15, 30 e 60 dias. As amostras foram analisadas sob microscopia de luz e MEV. Os resultados demonstraram formação de depósitos de nova matriz óssea preenchidos por pequenas quantidades de fibras colágenas II e III, no grupo 15 dias. Finas camadas de matriz óssea e osteoide em íntimo contato com a superfície das espiras centrais foram identificadas (30 dias), indicando elevada biocompatibilidade. Após 60 dias, o tecido ósseo mostrou características biológicas de maturidade e contato com a superfície. A porosidade superficial com média de 40 µm e profundidade com 5,3 µm demonstrou ser favorável à deposição óssea. O desenvolvimento de novas superfícies tratadas com equipamento a laser promovendo mudanças na energia superficial, assim como a macro e microestruturas, pode estimular novos estudos para o futuro da Implantodontia.

Roughness created implant titanium surfaces promote morphological alterations that may promote bone/implant contact. The surface energy resulting from blasting with particles, chemical attack and treatment by anodic oxidation on implant surfaces, promotes changes in the response of bone cells. The objective of this study was to evaluate the response of bone tissue on the implant surfaces treated under laser irradiation (Nd: YAG). The implants submitted to this method were examined under scanning electron microscopy (SEM), confocal 3-D and superficial evaluation by roughness tester equipment. Thirty mini-implants with superficial laser treatment and made in cp titanium grade II, were installed in Wistar rat femur. The animals were divided into three groups according to the periods of bone repair (15, 30 and 60 days). The samples were examined under light microscopy and SEM. The results demonstrated formation of new bone matrix filled with small amounts of collagen fibers II and III (15 days). Thin layers of bone and osteoid matrix in intimate contact with the surface of central threads were identified (30 days), indicating high biocompatibility. After 60 days the bone tissue showed biological characteristics of maturity and contact with the surface. The porosity surface with an average of 40 µm and depth with 5.3 µm proved to be favorable for bone deposition. The development of new areas treated with laser equipment, promoting changes in surface energy as well as the macro and microstructures, can stimulate new studies for the future of implantology.

Implant surface treatments affect gene expression of Runx2, osteogenic key marker

STATEMENT OF PROBLEM: The aim of this study was to study the effects of various surface treatments to a titanium surface on the expression of Runx2 in vitro. MATERIAL AND METHODS: Human Osteosarcoma TE-85 cells were cultured on machined, sandblasted, or anodic oxidized cpTi discs. At various times of incubation, the cells were collected and then processed for the analysis of mRNA expression of Runx2 using reverse transcription-PCR. RESULTS: The expression pattern of Runx2 mRNA was differed according to the types of surface treatment. When the cells were cultured on the untreated control culture plates, the gene expression of Runx2 was not increased during the experiments. In the case of that the cells were cultured on the machined cpTI discs, the expression level was intermediate at the first day, but increased constitutively to day 5. In cells on sandblasted cpTi discs, the expression level was highest in the first day sample and the level was maintained to 5 days. In cells on anodized cpTi discs, the expression level increased rapidly to 3 days, but decreased slightly in the 5-th day sample. CONCLUSION: Different surface treatments may contribute to the regulation of osteoblast function by influencing the level of gene expression of key osteogenic factors.