Punctal plug: a medical device to treat dry eye syndrome and for sustained drug delivery to the eye

Punctal plugs (PPs) are miniature medical implants that were initially developed for the treatment of dry eyes. Since their introduction in 1975, many PPs made from different materials and designs have been developed. PPs, albeit generally successful, suffer from drawbacks such as epiphora and suppurative canaliculitis. To overcome these issues intelligent designs of PPs were proposed (e.g. SmartPLUG™ and Form Fit™). PPs are also gaining interest among pharmaceutical scientists for sustaining drug delivery to the eye. This review aims to provide an overview of PPs for dry eye treatment and drug delivery to treat a range of ocular diseases. It also discusses current challenges in using PPs for ocular diseases.

Optimisation of a two-liquid component pre-filled acrylic bone cement system: A design of experiments approach to optimise cement final properties

The initial composition of acrylic bone cement along with the mixing and delivery technique used can influence its final properties and therefore its clinical success in vivo. The polymerisation of acrylic bone cement is complex with a number of processes happening simultaneously. Acrylic bone cement mixing and delivery systems have undergone several design changes in their advancement, although the cement constituents themselves have remained unchanged since they were first used. This study was conducted to determine the factors that had the greatest effect on the final properties of acrylic bone cement using a pre-filled bone cement mixing and delivery system. A design of experiments (DoE) approach was used to determine the impact of the factors associated with this mixing and delivery method on the final properties of the cement produced. The DoE illustrated that all factors present within this study had a significant impact on the final properties of the cement. An optimum cement composition was hypothesised and tested. This optimum recipe produced cement with final mechanical and thermal properties within the clinical guidelines and stated by ISO 5833 (International Standard Organisation (ISO), International standard 5833: implants for surgery—acrylic resin cements, 2002), however the low setting times observed would not be clinically viable and could result in complications during the surgical technique. As a result further development would be required to improve the setting time of the cement in order for it to be deemed suitable for use in total joint replacement surgery.

Semi-interpenetrating polymer networks incorporating polygalacturonic acid for medical device applications

Background Over 20 million people in the US are living with an implantable medical device [ADDIN RW.CITE{{3114 Higgins,DavidM 2009}}1], with similar figures anticipated for Europe. Complications in the use of medical implants include the Foreign Body Response (FBR) characterised by macrophage adherence and fusion, and device-related infection due to bacterial biofilm formationADDIN RW.CITE{{3124 Harding,JacquelineL 2014}}2. Both can have detrimental consequences on the structural and functional integrity of the medical device [ADDIN RW.CITE{{3101 Anderson,JamesM 2008; 3124 Harding,JacquelineL 2014}}2,3], often necessitating removal; a painful and expensive procedure [ADDIN RW.CITE{{3121 Mah,Thien-FahC 2001}}4]. Materials are sought to attenuate both the FBR and device-related infection, leading to medical devices with improved biocompatibility and performance. Objectives The present work involves development of a semi-interpenetrating network (SIPN) hydrogel containing polygalacturonic acid (PGA), a biopolysaccharide similar in structure to hyaluronic acid. We aim to synthesise, characterise and determine the in vitro biocompatibility of the developed SIPN. Results & Discussion We have successfully incorporated PGA into a poly(HEMA) based hydrogel, which shows favourable swelling and wettability. The surface topography appears altered in comparison to the control material, with pronounced micrometer-scale features. In terms of in vitro performance, the SIPN showed increased protein adsorption, and biofilm formation (Staphylococcus epidermidis and Escherichia coli, up to 1 Log CFU/sample greater than control). However the SIPN displayed minimal cytotoxicity towards L929 fibroblasts, and was resistant to the adherence of RAW 264.7 macrophages. Conclusions The PGA incorporated SIPN lacks cytotoxicity and shows reduced macrophage adherence, however the increased biofilm formation highlights a concern regarding possible device related infection in clinical use. Future work will focus on strategies to reduce bacterial adherence, while maintaining biocompatibility.

Prescription contraception use: a cross-sectional population study of psychosocial determinants

Objective: Many forms of contraception are available on prescription only for example, the oral contraceptive pill (OCP) and long-acting reversible contraceptives (LARCs). In this analysis we aim to identify key determinants of prescription contraceptive use.

Design: Cross-sectional population survey. Data on sociodemographic indices, concerns about the OCP and perceived barriers to access were collected.

Setting: Data set constructed from a representative population-based telephone survey of community dwelling adults in the Republic of Ireland (RoI)

Participants: 1515 women aged between 18 and 45 years

Main outcome measure: Self-reported user of the OCP or LARCs (intrauterine contraception, contraceptive injections or subdermal contraceptive implants) in the previous 12 months.

Results: For at least some of the previous year, 35% had used the OCP and 14% had used LARCs, while 3% had used two or more of these methods. OCP users were significantly younger, more likely to be unmarried and had higher income than non-users. Overall, 68% agreed with the statement ‘that taking a break from long-term use of the contraceptive pill is a good idea’ and 37% agreed with the statement that ‘the OCP has dangerous side effects’ and this was the strongest predictor variable of non-use of the OCP. Intrauterine contraception users were significantly older, more likely to be married and had lower income than non-users. Injections or subdermal contraceptive implant users were significantly younger, less likely to be married, had lower income and were less likely to agree that taking a break from long-term use of the pill is a good idea than non-users.

Conclusions: Prescription contraceptive use is sociodemographically patterned, with LARCs in particular being associated with lower incomes in the RoI. Concerns about the safety of the OCP remain prevalent and are important and modifiable determinants of contraceptive-related behaviour.

The determination of optimal processing conditions for PLA and PLA/CaCO3 in twin screw extrusion using DoE and multivariate analysis

Biodegradable polymers, such as PLA (Polylactide), come from renewable resources like corn starch and if disposed of correctly, degrade and become harmless to the ecosystem making them attractive alternatives to petroleum based polymers. PLA in particular is used in a variety of applications including medical devices, food packaging and waste disposal packaging. However, the industry faces challenges in melt processing of PLA due to its poor thermal stability which is influenced by processing temperatures and shearing.
Identification and control of suitable processing conditions is extremely challenging, usually relying on trial and error, and often sensitive to batch to batch variations. Off-line assessment in a lab environment can result in high scrap rates, long lead times and lengthy and expensive process development. Scrap rates are typically in the region of 25-30% for medical grade PLA costing between €2000-€5000/kg.
Additives are used to enhance material properties such as mechanical properties and may also have a therapeutic role in the case of bioresorbable medical devices, for example the release of calcium from orthopaedic implants such as fixation screws promotes healing. Additives can also reduce the costs involved as less of the polymer resin is required.
This study investigates the scope for monitoring, modelling and optimising processing conditions for twin screw extrusion of PLA and PLA w/calcium carbonate to achieve desired material properties. A DAQ system has been constructed to gather data from a bespoke measurement die comprising melt temperature; pressure drop along the length of the die; and UV-Vis spectral data which is shown to correlate to filler dispersion. Trials were carried out under a range of processing conditions using a Design of Experiments approach and samples were tested for mechanical properties, degradation rate and the release rate of calcium. Relationships between recorded process data and material characterisation results are explored.

Will your article be found? Authors choose a confusing variety of words to describe dental survival analyses

OBJECTIVES: Identify the words and phrases that authors used to describe time-to-event outcomes of dental treatments in patients.

MATERIALS AND METHODS: A systematic handsearch of 50 dental journals with the highest Citation Index for 2008 identified articles reporting dental treatment with time-to-event statistics (included "case" articles, n = 95), without time-to-event statistics (active "control" articles, n = 91), and all other articles (passive "control" articles n = 6796). The included and active controls were read, identifying 43 English words across the title, aim and abstract, indicating that outcomes were studied over time. Once identified, these words were sought within the 6796 passive controls. Words were divided into six groups. Differences in use of words were analyzed with Pearson's chi-square across these six groups, and the three locations (title, aim, and abstract).

RESULTS: In the abstracts, included articles used group 1 (statistical technique) and group 2 (statistical terms) more frequently than the active and passive controls (group 1: 35%, 2%, 0.37%, P < 0.001 and group 2: 31%, 1%, 0.06%, P < 0.001). The included and active controls used group 3 (quasi-statistical) equally, but significantly more often than the passive controls (82%, 78%, 3.21%, P < 0.001). In the aims, use of target words was similar for included and active controls, but less frequent for groups 1-4 in the passive controls (P < 0.001). In the title, group 2 (statistical techniques) and groups 3-5 (outcomes) were similar for included and active controls, but groups 2 and 3 were less frequent in the passive controls (P < 0.001). Significantly more included articles used group 6 words (stating the study duration) (54%, 30%, P = 0.001).

CONCLUSION: All included articles used time-to-event analyses, but two-thirds did not include words to highlight this in the abstract. There is great variation in the words authors used to describe dental time-to-event outcomes. Electronic identification of such articles would be inconsistent, with low sensitivity and specificity. Authors should improve the reporting quality. Journals should allow sufficient space in abstracts to summarize research, and not impose unrealistic word limits. Readers should be mindful of these problems when searching for relevant articles. Additional research is required in this field.

Experience of Managing Head and Neck Cancer Patients Amongst Specialty Trainees in Restorative Dentistry

Background: Upon completion of Specialty Training in Restorative Dentistry, trainees (StRs) should
be proficient in maxillofacial prosthodontics to meet the restorative needs of head and neck cancer patients (HANC), and in preparation for the Intercollegiate Specialty Fellowship Examination (ISFE).1,2
Objective: The aim of this study is to collate and compare data relating to the training of Restorative Dentistry Rs in the management of HANC patients across different geographical locations within the British Isles. Methods: Current trainees were invited to complete an online questionnaire by the Specialty Registrars in Restorative Dentistry Group (SRRDG). Participants were asked to rate their confidence and experience in assessing and planning treatment for HANC patients, attending theatre and manufacturing surgical obturators, and in providing implants for appropriate cases. Respondents were also asked to appraise clinical and didactic teaching within their unit, and to rate their confidence of passing oncology- based questions in a future ISFE. Results: Responses were obtained from 21 StRs (n=21) training in all five countries within the British Isles. Most respondents were based in England (76%). A third were in their 5th year of training. Less than half reported that they were confident
of independently assessing (48%) or treatment planning (38%) HANC patients. More than half of StRs (52%) indicated that they were not confident of attending theatres alone and manufacturing a surgical obturator. One third (33%) rated their experience of treating oncology patients with implants as poor or very poor, including three in their 5th year of training. Less than one third rated didactic teaching in maxillofacial prosthodontics at their unit as good or excellent. Only 4 respondents indicated that they were confident of answering an ISFE oncology question on management of healthcare delivery. Six StRs expressed concerns over a lack of case-based exposure.
Conclusion: Experience and training in maxillofacial prosthodontics is inconsistent for StRs across the British Isles with many lacking in clinical exposure.

Tooth replacement for partially dentate elders: a willingness-to-pay analysis

Objectives: The primary aim of this study was to investigate partially dentate elders’ willingness-to-pay (WTP) for two different tooth replacement strategies: using Removable Partial Dentures (RPDs) and, functionally orientated treatment (SDA). The secondary aim was to measure the same patient group’s WTP for dental implants. Methods: Patients who had completed a previous RCT comparing two tooth replacement strategies (RPDs and SDA) were recruited. 59 patients were asked to indicate their WTP for treatment to replace missing teeth in a number of hypothetical scenarios using the payment card method of contingency evaluation coupled to different costs. Data were collected on patients’ social class, longest held occupation, income levels and social circumstances. Results: The median age for the patient sample was 72.0 years (IQR: 71-75 years). Patients who had previously been provided with RPDs indicated that their WTP for this treatment strategy was significantly higher than those patients who had received SDA treatment (Mann-Whitney U Test: p<0.001). This group were also WTP a higher price for SDA treatment than those patients who had previously been treated according to this modality (Mann-Whitney U Test: p=0.005). The results indicated that patients’ age was not correlated with WTP but both social class and current income levels were significantly correlated (Spearman’s rank correlation: p<0.05). Patients in both treatment groups exhibited llittle WTP for dental implant treatment with a median price recorded which was lower than either RPD or SDA treatment. Conclusions: Amongst this patient cohort previous treatment experience had a strong influence on WTP as did social class and current income levels. The patients’ WTP indicated that they did not value dental implants over simpler forms of tooth replacement such as RPDs or a SDA approach.

Tooth replacement for partially dentate elders: a willingness-to-pay analysis

Objectives: The primary aim of this study was to investigate partially dentate elders’ willingness-to-pay (WTP) for two different tooth replacement strategies: using Removable Partial Dentures (RPDs) and, functionally orientated treatment (SDA). The secondary aim was to measure the same patient group’s WTP for dental implants.Methods: Patients who had completed a previous RCT comparing two tooth replacement strategies (RPDs and SDA) were recruited. 59 patients were asked to indicate their WTP for treatment to replace missing teeth in a number of hypothetical scenarios using the payment card method of contingency evaluation coupled to different costs. Data were collected on patients’ social class, longest held occupation, income levels and social circumstances.Results: The median age for the patient sample was 72.0 years (IQR: 71-75 years). Patients who had previously been provided with RPDs indicated that their WTP for this treatment strategy was significantly higher than those patients who had received SDA treatment (Mann-Whitney U Test: p<0.001). This group were also WTP a higher price for SDA treatment than those patients who had previously been treated according to this modality (Mann-Whitney U Test: p=0.005). The results indicated that patients’ age was not correlated with WTP but both social class and current income levels were significantly correlated (Spearman’s rank correlation: p<0.05).Patients in both treatment groups exhibited llittle WTP for dental implant treatment with a median price recorded which was lower than either RPD or SDA treatment.Conclusions: Amongst this patient cohort previous treatment experience had a strong influence on WTP as did social class and current income levels. The patients’ WTP indicated that they did not value dental implants over simpler forms of tooth replacement such as RPDs or a SDA approach.

Specialty Registrars’ Experience of Managing Head and Neck Cancer Patients

Objective The aim of this study was to collate and compare data on the training of Specialty Registrars in Restorative Dentistry (StRs) in the management of head and neck cancer (HANC) patients across different training units within the UK and Ireland. Methods Current trainees were invited to complete an online questionnaire by the Specialty Registrars in Restorative Dentistry Group (SRRDG). Participants were asked to rate their confidence and experience of assessing and planning treatment for HANC patients, attending theatre alone and manufacturing surgical obturators, and providing implants for appropriate cases. Respondents were also asked to appraise clinical and didactic teaching at their unit, and to rate their confidence of passing a future Intercollegiate Specialty Fellowship Examination (ISFE)-station assessing knowledge of head and neck cancer. Results Responses were obtained from 21 StRs (n=21) training within all five countries of the British Isles. Most respondents were based in England (76%), with one StR in each of Scotland, Wales, Northern Ireland and the Republic of Ireland. A third (33%) were in their 5th year of training. Almost half of the StRs indicated that they were confident of independently assessing (48%) new patients with HANC, with fewer numbers reporting confidence in treatment planning (38%). The majority (52%) of respondents indicated that they were not confident of attending theatre alone and manufacturing a surgical obturator. A third (33%) rated their experience of treating HANC patients with implants as ‘poor’ or ‘very poor’, including three StRs in their 5th year of training. Less than one third (<33%) rated didactic teaching in maxillofacial prosthodontics at their unit as ‘good’ or ‘excellent’, and only 7 StRs indicated that they were confident of passing an ISFE-station focused on HANC. Conclusion Experience and training regarding patients with head and neck cancer is inconsistent for StRs across the UK and Ireland with a number of trainees reporting a lack of clinical exposure.

Evaluation of Restorative Dentistry Specialty Registrars’ Clinical Experience of Developmental Disorders: A Survey

Background

Specialty Registrars in Restorative Dentistry (StRs) should be competent in the independent restorative management of patients with developmental disorders including hypodontia and cleft lip/palate upon completion of their specialist training.1 Knowledge and management may be assessed via the Intercollegiate Specialty Fellowship Examination (ISFE) in Restorative Dentistry.2

Objective

The aim of this study was to collate and compare data on the training and experience of StRs in the management of patients with developmental disorders across different training units within the British Isles.

Methods

Questionnaires were distributed to all StRs attending the Annual General Meeting of the Specialty Registrars in Restorative Dentistry Group, Belfast, in October 2015. Participants were asked to rate their confidence and experience of assessing and planning treatment for patients with developmental disorders, construction of appropriate prostheses, and provision of dental implants. Respondents were also asked to record clinical supervision and didactic teaching at their unit, and to rate their confidence of passing a future ISFE station assessing knowledge of developmental disorders.

Results

Responses were obtained from 32 StRs (n=32) training within all five countries of the British Isles. The majority of respondents were based in England (72%) with three in Wales, and two in each of Scotland, Northern Ireland, and the Republic of Ireland. Approximately one third of respondents (34%) were in the final years of training (years 4-6). Almost half of the StRs reported that they were not confident of independently assessing (44%) new patients with a developmental disorder, with larger numbers (72%) indicating a lack of confidence in treatment planning. Six respondents rated their experience of treating obturator patients as ‘poor’ or ‘very poor’. The majority (56%) rated their experience of implant provision in these cases as ‘good’ or ‘excellent’ with three-quarters (75%) rating clinical supervision at their unit as ‘good’ or ‘excellent’. Less than half (41%) rated the didactic teaching at their unit as ‘good’ or ‘excellent’, and only 8 StRs indicated that they were confident of passing an ISFE station focused on developmental disorders.

Conclusion

Experience and training regarding patients with developmental disorders is inconsistent for StRs across the British Isles with a number of trainees reporting a lack of clinical exposure.

Corrosion Fatigue Behaviour of Laser-welded Shape Memory NiTi Wires in a Simulated Body Fluid

Corrosion fatigue is a fracture process as a consequence of synergistic interactions between the material structure, corrosive environment and cyclic loads/strains. It is difficult to be detected and can cause unexpected failure of engineering components in use. This study reveals a comparison of corrosion fatigue behaviour of laser-welded and bare NiTi wires using bending rotation fatigue (BRF) test coupled with a specifically-designed corrosion cell. The testing medium was Hanks’ solution (simulated body fluid) at 37.5 oC. Electrochemical impedance spectroscopic (EIS) measurement was carried out to monitor the change of corrosion resistance of sample during the BRF test at different periods of time. Experiments indicate that the laser-welded NiTi wire would be more susceptible to the corrosion fatigue attack than the bare NiTi wire. This study can serve as a benchmark for the product designers and engineers to understand the corrosion fatigue behaviour of the NiTi laser weld joint and determine the fatigue life safety factor for NiTi medical devices/implants involving laser welding in the fabrication process.

Aplicações das redes de Bragg na biomecânica

O presente trabalho tem como objectivo o estudo, desenvolvimento e aplicações na área da biomecânica de sensores intrínsecos baseados em redes de Bragg em fibras ópticas (FBG). As aplicações são feitas em modelos biomecânicos in vitro tais como: implantes de anca, prótese de joelho, placas de osteossíntese e implantes dentários. A optimização do desenvolvimento de próteses e respectivos elementos de fixação é actualmente dependente da geração e validação experimental de seus modelos computacionais. A validação destes modelos é normalmente feita utilizando-se dados de ensaios não invasivos e invasivos em modelos sintéticos. Em ensaios in vitro os sensores convencionais têm um princípio de funcionamento eléctrico e apresentam por vezes dimensões inadequadas. Existem situações exploradas no presente trabalho, tais como sensoriamento de superfícies irregulares e junções ou ainda análises de deformações internas, onde é recomendável a utilização de sensores FBG, pois apresentam dimensões reduzidas e flexibilidade o que permite efectuar medidas localizadas. O desenvolvimento de um protocolo de utilização de FBG e a sua aplicação no contexto apresentado demonstrou-se mais adequado, pela precisão e segurança futura oferecidas. Foi desenvolvida uma metodologia experimental para medidas de deformações utilizando FBG ao longo de uma placa de osteossíntese metálica aparafusada a um fémur sintético fracturado. Foi efectuada a monitorização da cura do cimento ósseo utilizado como fixador do prato tibial na artroplastia total do joelho através da medida da sua contracção e temperatura. Foi também desenvolvido um sistema refrigerador com resposta às leituras de temperatura com vista a evitar a necrose do osso. Foram efectuados estudos de deformação nesse cimento após a sua cura, como resultado da aplicação de cargas mecânicas estáticas. Foram efectuados estudos da cura de cimento ósseo aplicado a próteses de anca e também de deformações nestas próteses. Foi ainda efectuado o estudo comparativo de vários implantes dentários através da medida da distribuição de deformações como resposta a excitações mecânicas impulsivas. Para a desmodulação das FBG foram inicialmente utilizados sistemas comerciais. Entretanto algumas aplicações não puderam ser implementadas com estes sistemas comerciais devido à baixa reflectividade das FBG utilizadas, mas fundamentalmente devido à necessidade de executar testes com uma taxa de aquisição maior do que os 5 Hz disponíveis (cerca de 15 kHz). Por estes motivos foi desenvolvido um sistema optoelectrónico completo de desmodulação de FBG baseado num filtro sintonizável e que tem como característica principal a alta taxa de aquisição (até 1,2 MHz) mas também se destaca pela facilidade na reconfiguração dos parâmetros de leitura, pela apresentação duma interface de utilizador amigável e pela capacidade de operar com até 5 FBG na mesma fibra óptica.

Nanocompósitos de PMMA/HA/grafeno para aplicações biomédicas

Os cimentos ósseos à base de PMMA para aplicações em artroplastia da anca apresentam como grande limitação o facto do seu constituinte principal ser um elemento bioinerte o que leva à falta de integração entre as interfaces cimento ósseo/tecido ósseo, comprometendo assim o desempenho mecânico da prótese ortopédica ao longo do tempo. Esta dissertação tem como objetivo principal a preparação de novas formulações de cimentos ósseos com a capacidade de estabelecer interações com os tecidos vivos circundantes. De modo a melhorar a bioatividade do sistema e facilitar a sua osseointegração, os cimentos ósseos comerciais foram reforçados com cargas significativas de HA. No entanto o recurso a elevadas cargas de HA (~60% m/m) no cimento ósseo promove debilidades do ponto de vista estrutural, levando a uma baixa resistência mecânica do material final. No sentido de ultrapassar esta limitação, foram inseridas nanoestruturas de carbono (GO ou CNTs) em baixas percentagens na matriz polimérica por forma a maximizar a sua performance mecânica através da perfeita integração de todos os componentes. A primeira fase deste trabalho consistiu no desenvolvimento de metodologias que permitissem a síntese de GO através da exfoliação química da grafite em solução aquosa. Os resultados obtidos demonstraram a obtenção de folhas de GO em larga escala e com número de camadas uniforme. A funcionalização orgânica superficial via ATRP do GO obtido, com cadeias de PMMA possibilitou o desenvolvimento de novos materiais nanocompósitos, no entanto alguns fatores de natureza tecnológica inviabilizaram o seu uso como agente de reforço na matriz idealizada. O desenvolvimento de novas formulações de cimentos ósseos consistiu numa matriz de PMMA/HA (1:2 (m/m)) reforçada com pequenas percentagens de GO ou CNTs (0,01, 0,1, 0,5 e 1,0% m/m). A síntese destes materiais nanocompósitos resultou da combinação de diversas técnicas: ultrassons, granulação por congelamento e liofilização. A análise estrutural dos nanocompósitos obtidos demonstrou a eficácia da metodologia desenvolvida na homogeneização de todos os elementos do sistema. Os estudos desenvolvidos após a conformação e caracterização estrutural dos novos materiais nanocompósitos permitiram verificar que as nanoestruturas de carbono apresentavam efeitos adversos na polimerização via radicalar do PMMA. A análise da fração orgânica permitiu verificar a presença de espécies oligoméricas o que reduziu significativamente o comportamento mecânico dos nanocompósitos. Através do estudo do aumento da concentração das espécies radicalares iniciais foi possível suplantar este problema e tirar o máximo rendimento dos agentes de reforço, tendo-se destacado os nanocompósitos reforçados com GO. A validação do ponto de vista mecânico das novas formulações de cimentos ósseos recaiu sobre o procedimento descrito na norma europeia ISO 5833 de 2002 – Implantes para cirurgia – cimentos acrílicos, tendo sido realizados os testes de compressão e de flexão. A avaliação biológica do comportamento dos cimentos ósseos assentou em duas abordagens complementares: estudos de mineralização em SBF e estudos de biocompatibilidade em meios celulares. Após a incubação das amostras em SBF ficou demonstrada a excelente capacidade para promoverem a integração de uma camada apatítica. Através de estudos celulares com Fibroblastos L929 e Osteoblastos Saos-2, nos quais foram avaliados a proliferação celular, viabilidade celular, espécies reativas de oxigénio, apoptose e morfologia celular, foi possível verificar bons níveis de biocompatibilidade para os materiais devolvidos.

Avaliação do desempenho in vivo do biovidro FastOs™

O conceito de bioatividade surgiu com a descoberta, no início década de 70, de que algumas composições vítreas (ex.: 45S5 Bioglass®), tinham a capacidade de estabelecer uma ligação direta e estável com os tecidos vivos. Desde então, este grupo de biomateriais tem vindo a receber uma atenção cada vez maior por parte dos investigadores, tendo como motivação principal a busca de novas composições com propriedades mais adequadas para a regeneração óssea do que as composições comercialmente disponíveis. Na presente tese, avaliou-se o desempenho in vivo de duas composições de biovidro do sistema diopsite (CaMgSi2O6) - fluorapatite (Ca5(PO4)3F) - fosfato tricálcico (3CaO•P2O5) aplicados em defeitos ósseos de tamanho não crítico em carneiros, tendo também sido avaliada a biocompatibilidade dos biomateriais através da aplicação subcutânea de placas dos mesmos vidros. O trabalho realizado também incluiu a avaliação dos materiais in vitro, através de estudos de biomineralização em fluido corporal simulado e estudos de degradação. Os biomateriais foram comparados com o biovidro 45S5 Bioglass®, sendo que em termos de bioatividade in vitro, as duas composições investigadas apresentaram um maior potencial bioativo, levando à formação de uma camada superficial de hidroxiapatite carbonatada, em contraste com a formação de calcite na composição comercial, sob condições idênticas. Os testes de degradação in vitro também apresentaram resultados melhores para as duas novas composições, traduzidos por variações de pH e taxas de degradação menores do que os observados no caso do 45S5 Bioglass®. A avaliação in vivo dos implantes subcutâneos permitiu apurar a biocompatibilidade dos biovidros testados, tendo sido considerados ligeiramente irritantes. Os resultados relativos à aplicação dos pós de vidro bioativo nos defeitos ósseos não foram obtidos em tempo útil de modo a poderem ser incluídos na presente tese. Considerando o desempenho in vitro e a biocompatibilidade dos materiais estudados, estes podem apontar-se como materiais promissores para aplicações em engenharia de tecidos, particularmente na regeneração do tecido ósseo.