In vivo osteogenesis and in vitro Streptococcus mutans adherence: porous-surfaced cylindrical implants vs rough-surfaced threaded implants.

PURPOSE: To analyze and compare bone apposition at the interface of commercially available rough-surfaced, threaded implants with porous-surfaced, cylindrical implants after several healing periods in a rabbit model. In addition, the study aimed to elucidate the influence of the implant surface configuration on Streptococcus mutans adherence. MATERIALS AND METHODS: Using a powder metallurgy technique, a new method was developed to produce titanium implants with a dense core and porous surface to increase bone-implant contact (BIC). Sixty implants were placed in 15 rabbits. In each rabbit, two experimental and two control implants were placed in the right or left tibia. The experimental implants were inserted under pressure into the surgical cavity, while the control implants were self-threaded. The rabbits were euthanized at 4, 8, and 12 weeks postinsertion for undecalcified histologic processing and morphometric evaluation of BIC. Additionally, 16 implants, eight experimental and eight control, were incubated with S. mutans to evaluate adherence for each type of implant. Analysis of variance with repeated measures and the Student t test were applied, respectively. RESULTS: Histology showed intimate bone-implant interfaces without soft tissue intervention in both groups. Porous-surfaced cylindrical implants showed a higher BIC (72.41% ± 9.47%) than the rough-surfaced screw implants (61.23% ± 14.12%) (P = .013), while no significant difference in S. mutans adherence occurred (P = .351). The implant type effect was more pronounced in the 4-week healing period groups (P = .029). The percentage of BIC was similar throughout the healing periods (P = .333), but gradually increased over time. CONCLUSION: Within the limitations of this study, the results suggest that the new implant design increased BIC without provoking greater S. mutans adherence.

Novel production method of porous surface Ti samples for biomedical application.

A porous implant material with adequate pore structure and the appropriate mechanical properties for bone ingrowth has long been sought. This article presents details of the development, characterization and in vivo evaluations of powder metallurgy-processed titanium samples exhibiting a dense core with an integrated porous surface for biomedical applications. A space-holder method was applied to investigate the effects of different percentages and particle sizes of the urea on bone neoformation in 30 rabbits. The samples were previously characterized using scanning electron microscopy and mechanical testing. After 8 and 12 weeks of implantation, bone ingrowth was histologically and histometrically analyzed and push-out testing was performed. This study demonstrated that the association of a dense core integrated with the greatest number of interconnected pores of the smallest size is a promising biomaterial for bone tissue engineering. This sample exhibits appropriate mechanical properties combined with increased bone ingrowth, providing enhanced resistance to displacement.

Impacto do trabalho auxiliado na qualidade de vida do cirurgião dentista / Impact of assisted work on dentist quality of life

De um modo geral, a utilização de pessoal auxiliar no consultório odontológico tornou-se fundamental para a melhoria na produtividade, influenciando de maneira direta na qualidade do trabalho e na diminuição do estresse e fadiga profissional. A proposta deste trabalho foi avaliar a qualidade de vida de cirurgiões–dentistas (CDs) que trabalham com e sem auxiliares em saúde bucal (ASBs) em consultórios dentários particulares, mediante aplicação do instrumento de medida validado para a população brasileira, Medical Outcomes Study 36 - Item Short Health Survey (SF-36). O questionário é composto por 11 questões e 36 itens, tendo como propósito avaliar 8 domínios divididos em 2 grandes componentes: o físico - que envolve a capacidade funcional, os aspectos físicos, a dor e o estado geral da saúde; e o mental - que abrange a saúde mental, os aspectos emocionais e sociais e a vitalidade. O estudo foi do tipo qualitativo descritivo e a amostra foi constituída de 60 CDs com no mínimo 10 anos de exercício profissional, de ambos os gêneros – 30 que trabalhavam auxiliados, na categoria de CD auxiliado e 30 que trabalhavam sem auxiliar, constituindo o grupo de CD não auxiliado. Os resultados obtidos com os testes de significância estatística ANOVA e TUCKEY mostram variação estatística com os domínios: capacidade funcional, dor, estado geral de saúde, vitalidade e aspectos sociais. No grupo de CDs estudado, a condição de trabalho auxiliado impacta positivamente a qualidade de vida considerando os domínios capacidade funcional, dor e estado geral de saúde

The use of auxiliary personnel has become a critical point for improving productivity in dental clinics. It directly contributes to reduction of professional stress and fatigue. The objective of this paper is to analyze and discuss the quality of life of dentists (CDs) who work with or without dental assistants in private dental clinics. A measuring tool that has been validated for the Brazilian population, namely the “Medical Outcomes Study 36 – Item Short Health Survey” (SF-36), was used. A questionnaire was developed with 11 questions and 36 items. The purpose was to evaluate each of eight areas that were divided into two major components: the physical (that involves the functional capacity, physical aspects, pain and general state of health) and the mental component (that covers mental health, emotional and social aspects and vitality). The research was of the qualitative-descriptive type and the sample was of 60 CDs, men and women, each with at least 10 years of professional experience; 30 out of them worked with assistants and 30 without. The results obtained with the ANOVA and TUKEY tests of statistical significance show statistical variation for functional capacity, pain, general health conditions, vitality and social aspects. In relation to functional capacity, pain and general health conditions, the study showed a positive impact over the quality of life of the group of dentists (CDs).

Osseointegração de implantes porosos de titânio submetidos ao tratamento biomimético / Osseointegration of porous titanium implants submitted to biomimetic treatment

Atualmente, as pesquisas em Implantodontia enfatizam modificações na superfície dos implantes, visando melhorar a osseointegração. Nesse sentido, o presente estudo teve como objetivo avaliar a influência da porosidade, bem como do tratamento biomimético (TB), na osteogênese in vivo em implantes de titânio. Foram confeccionados, por meio da metalurgia do pó, implantes de titânio puro grau 2, que foram divididos em seis grupos: a) G1: denso; b) G2: 40% de porosidade; c) G3: 50% de porosidade; d) G4: G1 + TB; e) G5: G2 + TB; f) G6: G3 + TB. Inicialmente, as amostras foram caracterizadas por análise metalográfica e porespectroscopia por energia dispersiva (EDS). Em seguida, os implantes foram inseridos nas tíbias de dezesseis coelhos da raça Nova Zelândia, para avaliar a reparação óssea peri-implantar, por meio de análise histológica e histomorfométrica. Como padronização, os implantes G1, G2e G3 foram inseridos na tíbia direita e G4, G5 e G6 na esquerda. Quatro coelhos, selecionados aleatoriamente, foram submetidos à eutanásia, 01,02, 04 e 08 semanas após a cirurgia. Os dados da análise metalográfica foram submetidos ao teste de Kruskal-Wallis e a análise histomorfométrica foi avaliada pelos testes ANOVA e Tukey. Os resultados da metalografia confirmaram porosidade de 40 e 50%, e revelaram poros com tamanho médio de 370 μm e interconexão entre os mesmos. Na análise por EDS foi observada a presença de íons Ca e P, caracterizando o sucesso do TB. Na análise histológica observou-se neoformação óssea, inclusive para o interior dos poros, independente do tipo de implante ou do tempo. Na análise histomorfométrica, verificou-se maior neoformação óssea em G5 e G6, e menor em G1, sendo que ambas as condições mostraram diferença estaticamente significante em relação aos demais grupos. Concluiu-se que o TB associado à porosidade exerce influência positiva na neoformação óssea

Researches in implantodontology have been recently focusing on implantsurface modifications aiming to improve osseointegration. Thus, thepurpose of the present study was to evaluate in vivo the influence oftitanium implants surface porosity and surface biomimetic treatment (BT)on osteogenesis. Grade 2 pure titanium implants were fabricated bymeans of powder metallurgy and divided into six groups: a) G1: dense; b)G2: porosity of 40%; c) G3: porosity of 50%; d) G4: G1 + BT; e) G5: G2 +BT; and f) G6: G3 + BT. The samples were initially characterized bymetallographic analysis and energy-dispersive spectroscopy (EDS). Theimplants were then placed into the tibia of sixteen New Zealand rabbits inorder to evaluate the peri-implant bone repair by means of histological andhistomorphometric analyses. As standardization, implants from groupsG1, G2 and G3 were inserted into right tibias; while G4, G5 and G6 intoleft ones. Four randomly chosen rabbits underwent euthanasia 01, 02, 04and 8 weeks after surgery. The results from metallographic analysis wereanalyzed by Kruskal-Wallis test and the histomorphometric results byANOVA and Tukey tests. Metallographic results confirmed porositybetween 40 and 50%, and revealed mean pore size of 370 μm andinterconnection among them. EDS analysis detected the presence of Caand P ions, confirming BT success. Bone neoformation, including into thepores, was detected by the histological analysis regardless the type ofimplant or evaluated period. By the histomorphometric analysis, boneneoformation was statistically greater for G5 and G6 and statistically lesserfor G1 in comparison to the other groups. It was concluded that BTassociated with porosity exerts positive influence on bone neoformation

Porous titanium for biomedical applications: an experimental study on rabbits.

OBJECTIVE: The aim of this study was to carry out an in vivo assessment of bone ingrowth in two different types of porous titanium -the first being completely porous, and the second with a porous surface and dense nucleus, manufactured by powder metallurgy- and to evaluate their mechanical properties. STUDY DESIGN: Ten scaffolds from each group were submitted to metallographic analysis and compression tests. Next, two scaffolds of each type were inserted into 14 rabbits, which were sacrificed 8 weeks after surgery. The samples were submitted for histological examination. RESULTS: Metallographic analysis revealed interconnected pores, and the average interconnected pore diameter was about 360 mm, with 36% total porosity. The totally porous titanium samples and the titanium samples with porous surface and dense nucleus showed an average compressive strength of 16.19 MPa and 69.27 MPa, respectively. After 8 weeks, the animals showed bone ingrowth, even into the most internal pores. CONCLUSIONS: The pore morphology was effective in permitting bone ingrowth in both groups. Titanium scaffolds with a porous surface and dense nucleus showed the best mechanical properties and most adequate interface.