Aurelício Novaes Silva Júnior

Computerized Morphometric Assessment of the Effect of Low-Level Laser Therapy on Bone Repair: An Experimental Animal Study

OBJECTIVE The aim of this study was to evaluate morphometrically the amount of newly formed bone after GaAlAs laser irradiation of surgical wounds created in the femur of rats. BACKGROUND DATA Low-level laser therapy (LLLT) has been used in several medical specialties because of its biomodulatory effects on different biological tissues. However, LLLT is still controversial because of contradictory reports. This is a direct result of the different methodologies used in these works. MATERIALS AND METHODS In this study, 40 Wistar rats were divided into four groups of 10 animals each: group A (12 sessions, 4.8 J/cm2 per session, observation time of 28 days); group C (three sessions, 4.8 J/cm2 per session, observation time of 7 days). Groups B and D acted as nonirradiated controls. The specimens were routinely processed to wax and cut at 6-microm thickness and stained with H&E. For computerized morphometry, Imagelab software was used. RESULTS Computerized morphometry showed a significant difference between the areas of mineralized bone in groups C and D (p = 0.017). There was no difference between groups A and B (28 days; p = 0.383). CONCLUSION It is concluded that, under this experimental condition, LLLT increased bone repair at early bone healing.

Effect of titanium surface roughness on human bone marrow cell proliferation and differentiation: an experimental study

PURPOSE To assess the proliferation and differentiation of human bone marrow-derived cells cultured on titanium surfaces with different roughness characteristics. METHODS Cells obtained from the iliac crest of an adult human donor were routinely processed and cultured on titanium surfaces of varying roughness, according to their preparation method: polishing only (smooth surface) and polishing followed by etching with HF/HNO3 for 15 and 30 minutes (rough surfaces). Surfaces were assessed using scanning electronic microscopy and profilometry. RESULTS Titanium disks etched with acid for 15 minutes allowed greater cell proliferation in all culture periods. The level of osteopontin and osteocalcin expression was increased in both acid-etched groups, which indicates an advanced stage of differentiation of cells into osteoblasts. CONCLUSIONS Increased surface roughness accelerates the differentiation of undifferentiated mesenchymal cells into osteogenic lineage cells, but does not necessarily favor cell proliferation. An intermediate surface roughness of 0.5microm (acid etching for 15 minutes) favors both initial and final cell responses.

Alpha-tricalcium phosphate cement in the reconstruction of bone defects in rats

PURPOSE To evaluate the ability of a mixture of α-TCP and autogenous bone (AB) vs. α-TCP alone and AB alone to promote new bone formation and tissue repair in bone defects. METHODS Bone defects surgically created in 15 male Wistar rats were divided into four groups: Group I (AB), Group II (α-TCP), Group III (α-TCP+AB assessed by light microscopy), and Group IV (α-TCP+AB assessed by scanning electron microscopy). Bone repair findings were assessed at 30, 60, and 120 days postoperatively. RESULTS The histological findings obtained in Groups I (p=0.459), II (p=0.368), and III (p=0.459) and at 30 days (p=0.717), 60 days (p=0.717), and 120 days (p=0.779) did not show statistically significant differences. Scanning electron microscopy revealed direct contact between the α-TCP+AB implant and the bone tissue at 120 days. CONCLUSION The α-TCP implant is effective alternative bone substitutes for the treatment of critical size bone defects.

Profilaxia antibiótica de infecção pós-operatória nos períodos pré e pós-operatórios em cirurgia de terceiros molares

O uso rotineiro de profilaxia antibiotica em cirurgia para exodontia de terceiros molares e controverso. O objetivo deste trabalho foi analisar a conduta farmacologica de cirurgioes-dentistas que realizam este tipo de extracao dentaria em relacao a profilaxia de infeccoes pos-operatorias, comparando os dados a conduta dos professores das disciplinas de Cirurgia Bucomaxilofacial do curso de Odontologia da Universidade Luterana do Brasil, Canoas/RS. Para tanto, foi aplicado um questionario a 60 profissionais com o intuito de verificar os criterios de indicacao de profilaxia antibiotica para infeccoes pos-operatorias, posologia farmacologica e associacao com controle quimico do biofilme bacteriano, relacionando essas variaveis ao curso de origem e tempo de formado do profissional. Conclui-se que a maioria dos entrevistados indica profilaxia para infeccoes pos-operatorias, entretanto nao segue um protocolo definido sustentado em evidencias cientificas.

Avaliação do efeito do laser não cirúrgico (LLLT) no crescimento e aderência celular de fibroblastos cultivados sobre implantes de titânio: um estudo in vitro

Recentemente, a laserterapia tem sido utilizada em odontologia visando aos seus efeitos terapeuticos e biomodulatorios sobre o aumento da velocidade e qualidade da integracao entre os implantes dentais e os tecidos osseo e periodontal. Entretanto, permanece incerto se e possivel haver bioestimulacao do crescimento celular pelo laser na presenca de implantes de titânio. O objetivo do presente estudo foi examinar o crescimento, a proliferacao e aderencia sobre a superficie de titânio de uma linhagem de fibroblastos (NIH-3T3) submetida a irradiacao com laser diodo (l=685nm). Dois grupos com quatro culturas cada foram cultivados sobre discos de titânio previamente polidos e colocados numa placa de 24 pocos. As celulas foram cultivadas em meio DMEM suplementado com 10% de soro fetal bovino (SFB). Apos o cultivo, um grupo foi irradiado localmente por tres sessoes (24, 48 e 72 horas) (laser diodo l=685nm, 07mW, AE~0,60mm), com uma dose de 0,8 J.cm-2 por sessao, e o outro foi mantido sem qualquer tratamento. Um grupo de controle de celulas cultivadas sobre a placa tambem foi conduzido. A aderencia celular foi avaliada pela tecnica de coloracao com um agente intercalante de DNA (iodeto de propidio) e o crescimento celular, pela contagem em hemocitometro. De acordo com a contagem do numero de celulas observadas em cada grupo, foi possivel determinar nos grupos experimentais um aumento estatisticamente significativo no numero medio de celulas nos periodos de 72 (p=0,010) e 96 horas (p=0,007) apos o cultivo quando comparados com seus respectivos controles. Este estudo sugere que o laser, nas condicoes descritas, pode afetar positivamente a proliferacao celular in vitro e, assim, pode desempenhar uma importante funcao na integracao entre os implantes dentais e o tecido periodontal.