The aims of this study were to analyze prospectively and comparatively the peri-implant bone crest levels, bone density, stability and success rate of implants with different surface treatments in human edentulous mandibles. Twenty edentulous patients were selected. Four different implants were placed between the mental foramen. Four groups were evaluated: (1) lasermodified surface (LASER), (2) surface modified by laser with deposition of apatites (LASER ? HA), (3) surface modified by double acid etching (ACID, Implacil De Bortoli) and (4) surface modified by sandblasting and acid etching (SLActiveÒ, Straumann). Clinical, radiographic, resonance frequency and tomographic analyses were used. After 4 months, mandibular fixed implant prostheses were installed. Clinical and radiographic analyses were performed at times T0 (immediately after implant placement), T1 (15 days), T2 (30 days), T3 (60 days), T4 (90 days), T5 (120 days), T6 (180 days) and T7 (360 days), post-implant placement. The resonance frequency analysis (RFA) was measured at T0, T4, T6 and T7. The tomographic analysis was performed at T0, T4 and T7. In the radiographic bone density analysis, a statistical difference was found between the SLActiveÒ and LASER ? HA groups at T4 (p \ 0.05). Statistical differences were observed in RFA at T4 (90 days), between the SLActiveÒ and LASER groups (p \ 0.05) and between the SLActiveÒ and LASER ? HA groups (p \ 0.05). At T6 and T7, statistical differences were found between the SLActiveÒ group and all other implant surfaces (p \ 0.01). The experimental surfaces analyzed showed encouraging positive outcomes compared to those of the SLActiveÒ surface. Long-term follow-up should be performed to confirm these results.

Clinical comparison of short and conventional implants placed in the posterior region of the mandible. A pilot study ResumoObjetivo: Avaliar e correlacionar os valores de densidade óssea radiográfica, altura óssea peri-implantar e de frequência de ressonância nos implantes curtos e convencionais instalados na região posterior da mandíbula após a instalação da prótese provisória. Material e método: Esse estudo piloto clínico prospectivo contou com a participação de 11 pacientes que foram divididos previamente em dois grupos: implantes curtos (n=18) (5,0 x 5,5 mm e 5,0 x 7,0 mm) e implantes convencionais (n=23) (4,0 x 10 mm e 4,0 x 11,5 mm). Foram executadas análise da frequência de ressonância, altura óssea e densidade óssea peri-implantar. Os implantes foram avaliados nos períodos T0 (imediatamente após a instalação do provisório), T1 (após 90 dias) e T2 (após 180 dias). Resultado: Não houve diferenças estatisticamente significativas entre os grupos com relação a densidade óssea radiográfica (152,50 ± 15,39 vs. 157,60 ± 28,46, para implantes convencionais e curtos respectivamente no período T2), estabilidade dos implantes (Implantes convencionais: 66,76 ± 10,39 no período T0 e 61,85 ± 8,38 no período T2 vs. Implantes curtos: 57,50 ± 12,17 no período T0 e 61,53 ± 7,39 no período T2) e quanto a perda óssea periimplantar (0,03 mm vs. -0,17 mm, em implantes convencionais e curtos no período T2, respectivamente). Adicionalmente a isso, não foram detectados correlação significativa entre densidade radiográfica com altura óssea peri-implantar e nem com a frequência de ressonância. Conclusão: Verificou-se que os implantes curtos apresentaram um comportamento semelhante aos implantes de comprimento convencionais com relação à frequência de ressonância, a densidade radiográfica peri-implantar e a manutenção dos níveis ósseos periimplantares.Descritores: Reabsorção óssea; densidade óssea; próteses e implantes. AbstractObjective: To evaluate and correlate the values of radiographic bone density, peri-implant bone height and resonance frequency analysis (RFA) of short or conventional implants placed in the posterior region of the mandible after installing a prosthesis. Material and method: Eleven patients were selected for this prospective parallel pilot study. The prostheses were supported by two types of implants: short implants (n = 18) (5.0 x 5.5 mm and 5.0 x 7.0 mm) and conventional implants (n = 23) (4.0 x10 mm and 4.0 x 11.5 mm). The implants were evaluated by RFA, by measuring the bone height, and peri-implant bone density. The implants were evaluated at the periods T0 (immediately after installation of the prosthesis), T1 (after 90 days), and T2 (after 180 days). Result: There were no statistically significant differences between groups with respect to radiographic bone density (152.50 ± 15.39 vs. 157.60 ± 28.46, for conventional and short implants, respectively at T2), stability of the implants (Conventional implants: 66.76 ± 10.39 at T0, and 61.85 ± 8.38 at T2 vs. Short implants: 57.50 ± 12.17 at T0, and 61.53 ± ...