Materials and Techniques Used in Cranioplasty Fixation: A Review

Cranioplasty is the surgical repair of a deficiency or deformity of the skull. The purpose of cranioplasty is to provide protection for the brain following cranial surgery, and to offer relief to psychological disadvantages while increasing social performance. There are several materials that had been used for cranioplasty, but an ideal product has yet to be developed, hence the ongoing research into biologic and non-biologic alternatives to the existing materials. This article critiques the products currently used for cranioplasty in order to facilitate the development of new materials, which can improve patient outcomes

Fiber-reinforced composite fixed dental prostheses: Studies of the materials used as pontics

Fiber-reinforced composite fixed dental prostheses – Studies of the materials used as pontics University of Turku, Faculty of Medicine, Institute of Dentistry, Department of Biomaterials Science, Finnish Doctoral Program in Oral Sciences – FINDOS, Annales Universitatis Turkuensis, Turku, Finland 2015 Fiber-reinforced composites (FRC), a non-metallic biomaterial, represent a suitable alternative in prosthetic dentistry when used as a component of fixed dental prostheses (FDPs). Some drawbacks have been identified in the clinical performance of FRC restorations, such as delamination of the veneering material and fracture of the pontic. Therefore, the current series of studies were performed to investigate the possibilities of enhancing the mechanical and physical properties of FRC FDPs by improving the materials used as pontics, to then heighten their longevity. Four experiments showed the importance of the pontic design and surface treatment in the performance of FRC FDPs. In the first, the load-bearing capacities of inlay-retained FRC FDPs with pontics of various materials and thicknesses were evaluated. Three different pontic materials were assessed with different FRC framework vertical positioning. Thicker pontics showed increased load-bearing capacities, especially ceramic pontics. A second study was completed investigating the influence of the chemical conditioning of the ridge-lap surface of acrylic resin denture teeth on their bonding to a composite resin. Increased shear bond strength demonstrated the positive influence of the pretreatment of the acrylic surfaces, indicating dissolution of the denture surfaces, and suggesting potential penetration of the monomer systems into the surface of denture teeth. A third study analyzed the penetration depth of different monomer systems on the acrylic resin denture teeth surfaces. The possibility of establishing a durable bond between acrylic pontics and FRC frameworks was demonstrated by the ability of monomers to penetrate the surface of acrylic resin denture teeth, measured by a confocal scanning type microscope. A fourth study was designed to evaluate the load-bearing capacities of FRC FDPs using the findings of the previous three studies. In this case, the performance of pre-shaped acrylic resin denture teeth used as pontics with different composite resins as filling materials was evaluated. The filling material influenced the load-bearing capacities, providing more durable FRC FDPs. It can be concluded that the mechanical and physical properties of FRC FDPs can be improved as has been shown in the development of this thesis. The improvements reported then might provide long lasting prosthetic solutions of this kind, positioning them as potentially permanent rehabilitation treatments. Key words: fiber-reinforced composite, fixed dental prostheses, inlay-retained bridges, adhesion, acrylic resin denture teeth, dental material.Kuitulujitteiset hammassillat – välihampaan materiaalien ominaisuuksien paran- taminen Turun yliopisto, Lääketieteellinen tiedekunta, Hammaslääketieteen laitos, Biomateriaa- litieteen oppiaine, Kansallinen suun terveystieteiden tohtoriohjelma – FINDOS, Annales Universitatis Turkuensis, Turku, Suomi, 2015. Kuitulujitteinen muovi (engl. fiber-reinforced composite, FRC) on metalliton biomate- riaalinakin käytetty materiaali, jonka eräs hammaslääketieteellinen käyttökohde on hammassiltojen runkorakenteissa. Kliininen käyttökokemus on osoittanut, että eräs kuitulujitteisen sillan heikkous on lasikuiturungon ja puuttuvaa hammasta korvaavan ns. välihampaan irtoaminen toisistaan. Tämän tutkimuksen tarkoituksena oli tutkia ja kehittää keinoja välihampaan ja lasikuiturungon välisen liitoksen lujuuden lisäämiseksi materiaaliopillisilla keinoilla. Tavoitteena oli pidentää kuitulujitteisten hammassiltojen käyttöaikaa. Neljä koesarjaa osoittivat välihampaan kiinnityspinnan materiaalin, muodon ja pinta- käsittelyn vaikutuksen sillan kestävyyteen. Ensimmäisessä tutkimusosassa selvitettiin eri materiaalien purupinnan kerrospaksuuden vaikutusta sillan kestävyyteen. Väliham- paan purupintamateriaalin paksuuden lisääminen lujitti siltaa erityisesti keraamista välihammasta käytettäessä. Toisessa tutkimusosassa tarkasteltiin muovisen väliham- paan kiinnityspinnan kemiallisen pintakäsittelyn vaikutusta liimasauman lujuuteen. Lii- masauman lujuutta saatiin lisättyä kemiallisella käsittelyllä, joka liuotti välihampaan kiinnityspintaa. Työssä havaittiin liima-aineen monomeerien imeytymistä välihampaan pintakerrokseen. Kolmannessa työssä kiinnitettiin huomio liima- ja pintakäsittelyaineiden monomeerien imeytymiseen kiinnityshampaan pintakerrokseen. Aineiden imeytymissyvyys määri- tettiin konfokaalimikroskopialla ja imeytymissyvyyden ja liimasauman lujuuden välillä havaittiin yhteys. Neljännessä tutkimusosassa mitattiin valmiin hammassillan lujuutta, ns. kuormituksen kantokykyä. Sillan välihammas oli valmistettu etukäteen muotoil- lusta kuorimaisesta proteesihampaasta, jonka kiinnittyminen sillan lasikuiturunkoon aikaansaatiin erilaisilla täytemuoveilla. Tuloksena todettiin, että pintakäsittelyn lisäksi välihampaan ja sillan rungon välissä olevalla täytemuovilla on keskeinen merkitys sil- lan kestävyydelle. Yhteenvetona todettiin, että kuitulujitteisen hammassillan kestävyyttä voitiin lisätä vai- kuttamalla välihampaan materiaaliin ja sen kiinnittymiseen sillan lasikuiturunkoon. Klii- niseltä kannalta tuloksia voidaan käyttää hyödyksi valmistettaessa pitkäikäisiä kuitulujit- teisia hammassiltoja. Avainsanat: Kuitulujittenen muovi, hammassillat, välihammas, lujitemuovi, sidostaminen, liimaaminen, komposiitti, proteesihammasSiirretty Doriast

Antibacterial polymethylmethacrylate (PMMA)/ beta tri calsium phosphate/ zinc oxide composites for craniofacial reconstruction

Polymethylmethacrylate (PMMA) is commonly used in dental and bone reconstruction applications due to the excellent properties such as biocompatible, biologically inert and rigid. In craniofacial, traumatic injuries will result to the defect of underlying brain. Somehow, after reconstruction of scull using PMMA, the infection may occur. Thus, incorporation of antibacterial agent such as beta tricalcium phosphate (β-TCP) to the PMMA is desirable to eliminate infection. Also, the presence of β-TCP to the composites is one of the alternatives to promote cell growth to the surrounding bone tissue. Hence, in this study, PMMA composites fabricated with specified percentages of filler content of β-TCP and Zinc Oxide. The composites divided into three groups of different percentages of 5, 10, 15% β-TCP without ZnO, and another two groups, 2.5% and 5% ZnO were added 15% β-TCP. The size of β- TCP was approximately 1-5μm and ZnO was in nano size (256nm). The mechanical characteristics, chemical bonding, and physical properties of the specimen were next assessed. The characterization of specimen was then evaluated for mechanical properties, chemical bonding, physical properties. Observations of the microstructure of the fracture surface were performed by Field Emission scanning electron microscopy (FESEM). Chemical groups existed were confirmed with analysis of Fourier Transmission InfraRed (FTIR). The mechanical properties showed the improvement for PMMA composites. There is significant difference detected between PMMA pure and PMMA composites in physical properties. The cytotoxicity effect was investigated through 3-(4, 5-dimethylthiazoyl)-2-5 diphenyl-tetrazolium bromide (MTT assay), using human fetal osteoblast cell (hFOB). The hFOB cultured with 25 mg/ml PMMA filled 15% βTCP and 5% ZnO demonstrated the highest cell viability (132.73%). The percentages of cell viability of samples with 50 mg/ml and below showed no cytotoxicity effect due to their value of cell viability were more than 70%. The antibacterial properties of the PMMA composite were evaluated using agar diffusion and growth curve methods against Gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa). A significant difference was observed with the incorporation of ZnO filler in the agar diffusion test. The antibacterial property of PMMA composites were further evaluated with a growth curve and significant antibacterial activity was found on PMMA composites with 2.5% and 5% of ZnO filled. In conclusion, PMMA composites at 2.5% and 5% ZnO, are promising biomaterials that suit to be applied as implants in craniofacial reconstruction

Fiber-reinforced composite with interpenetrating polymer network - Influence of shelf-life of the prepreg and the adhesive primer on interfacial adhesive strength of the composite to a resin luting material

Fiber-reinforced composite (FRC) is a low-cost metal-free restorative alternative. To overcome problems related to the interfacial adhesion between composite luting material and FRC, a semi-interpenetrating polymer network (semi-IPN) matrix with linear polymer of poly(methylmethacrylate) (PMMA) was developed for FRC. Therefore, a series of laboratory studies were executed to investigate the effect of shelf-life, monomer systems and PMMA gradient on the intact and ground substrates of semi-IPN FRC. In the four experimental studies, everStick C&B was used as the semi-IPN based FRC. The first study evaluated the shelf-life and dissolving capability of the methyl methacrylate (MMA) monomer in polymerized FRC. The second study investigated the effect of different adhesive/primer on polymerized FRC which were stored for various durations (at 4°C; 1.0, 1.5, and 3-year) before curing. The third study analyzed the tensile bond strength (TBS) between resin luting material and FRC using different adhesive/primers systems. The fourth study determined TBS between polymerized FRC intact (high gradient PMMA) or ground (low gradient PMMA) surfaces and a resin luting material. The results were statistically analyzed using analysis of variance (ANOVA), the post hoc Tukey’s test, regression and correlation analysis using statistical software. It can be concluded that upon aging, the linear and cross-linked components of the semi-IPN structure of FRC might become phase-segregated. Both G-Multi PRIMER and Composite Primer might have the ability to diffuse into polymerized FRC and form a durable adhesive layer with increased nanohardness and adhesive strength between resin luting material and the FRC substrate. The highest TBS can be achieved for FRC intact surface treated with the G-Multi PRIMER.Osittaislomittaismuoviverkostorakenne kuitulujitteissa muovissa – muovin esivalmisteen säilytysajan ja pinnan esikäsittelyajan vaikutus muovin rajapintaliitoksen sidoslujuuteen. Kuitulujittenen muovi on hammashoidon materiaali, joka täyttää hammaslääketieteen asettamat ulkonäölliset ja lujuusvaatimukset. Kuitulujitteinen muovi koostuu lujitekuiduista ja niitä sitovasta yleensä ristisilloitetusta muovimatriisista, joka voi olla myös osittaislomittaisverkostomuovirakenne (engl. semi-IPN). Tässä tutkimuksessa selvitettiin kuitulujite-esivalmisteen säilytysajan ja kovetetun kuitulujiteteisen muovin pinnan esikäsittelyn vaikutusta muovin liimautumiseen muihin hammaslääketieteessä käytettyihin muoveihin. Tutkimuksessa käytettiin semi-IPN muovipitoista kuitulujitteista muovia. Kuitulujitteisen muovin pinnan rakennetta ja ominaisuuksia tutkittiin muovin kovettamisen jälkeen. Vertailua tehtiin muun muassa nanomekaanisella pinnan analysoinnilla niistä muoveista, joiden esivalmistetta oli säilytetty jopa kaksi vuotta ennen näytteen valmistusta. Lisäksi tutkimuksessa kiinnitettiin erityistä huomiota kuitulujitteisen muovin liimautumiseen toiseen muoviin ja tällöin verrattiin erilaisten pinnan esikäsittelyaineiden vaikutusta rajapintaliitoksen sidoslujuuteen. Tulokset osoittivat tilastollisesti merkitseviä eroja näytteen pinnan nanokovuudessa pinnan eri kerrossyvyyksissä, mikä osoittaa semi-IPN gradienttirakenteen olemassaolon. Käytetyt kaksi esikäsittelyainetta saivat rajapintaliitoksen pinnan kovuuden lisääntymään näytteissä, jotka oli valmistettu tuoreesta kuitulujitteisen muovin esivalmisteesta. Myös esivalmisteen säilytysaika ennen sen käyttämistä vaikutti merkitsevästi liimautumiseen. Korkein sidoslujuus saavutettiin kuitulujitteisella muovilla, jonka pintaa ei oltu hiottu ennen liimaamista eli pinnan gradienttirakennetta ei oltu poistettu

Biocompatibility issues with modern implants in bone: a review for clinical orthopaedics

Skeletal defects may result from traumatic, infectious, congenital or neoplastic processes and are considered to be a challenge for reconstructive surgery. Although the autologous bone graft is still the “gold standard”, there is continuing demand for bone substitutes because of associated disadvantages, such as limited supply and potential donor side morbidity [1]. This is not only true for indications in orthopedic and craniomaxillofacial surgeries, but also in repairing endodontic defects and in dental implantology. Before clinical use all new bone substitute materials have to be validated for their osseoconductive and - depending on the composition of the material also -inductive ability, as well as for their long-term biocompatibility in bone. Serving this purpose various bone healing models to test osteocompatibility and inflammatory potential of a novel material on one hand and, on the other hand, non-healing osseous defects to assess the healing potential of a bone substitute material have been developed. Sometimes the use of more than one implantation site can be helpful to provide a wide range of information about a new material [2]. Important markers for biocompatibility and inflammatory responses are the cell types appearing after the implantation of foreign material. There, especially the role of foreign body giant cells (FBGC) is discussed controversial in the pertinent literature, such that it is not clear whether their presence marks an incompatibility of the biomaterial, or whether it belongs to a normal degradation behavior of modern, resorbable biomaterials. This publication is highlighting the different views currently existing about the function of FBGC that appear in response to biomaterials at the implantation sites. A short overview of the general classes of biomaterials, where FBGC may appear as cellular response, is added for clarity, but may not be complete

Biocompatibility Issues with Modern Implants in Bone - A Review for Clinical Orthopedics

Skeletal defects may result from traumatic, infectious, congenital or neoplastic processes and are considered to be a challenge for reconstructive surgery. Although the autologous bone graft is still the “gold standard”, there is continuing demand for bone substitutes because of associated disadvantages, such as limited supply and potential donor side morbidity [1]. This is not only true for indications in orthopedic and craniomaxillofacial surgeries, but also in repairing endodontic defects and in dental implantology

The state of additive manufacturing in dental research – A systematic scoping review of 2012–2022

Background/purpose: Additive manufacturing (AM), also known as 3D printing, has the potential to transform the industry. While there have been advancements in using AM for dental restorations, there is still a need for further research to develop functional biomedical and dental materials. It’s crucial to understand the current status of AM technology and research trends to advance dental research in this field. The aim of this study is to reveal the current status of international scientific publications in the field of dental research related to AM technologies. Materials and methods: In this study, a systematic scoping review was conducted using appropriate keywords within the scope of international scientific publishing databases (PubMed and Web of Science). The review included related clinical and laboratory research, including both human and animal studies, case reports, review articles, and questionnaire studies. A total of 187 research studies were evaluated for quantitative synthesis in this review. Results: The findings highlighted a rising trend in research numbers over the years (From 2012 to 2022). The most publications were produced in 2020 and 2021, with annual percentage increases of 25.7% and 26.2%, respectively. The majority of AM-related publications in dentistry research originate from Korea. The pioneer dental sub-fields with the ost publications in its category are prosthodontics and implantology, respectively. Conclusion: The final review result clearly stated an expectation for the future that the research in dentistry would concentrate on AM technologies in order to increase the new product and process development in dental materials, tools, implants and new generation modelling strategy related to AM. The results of this work can be used as indicators of trends related to AM research in dentistry and/or as prospects for future publication expectations in this field

Biomaterial-based strategies for craniofacial tissue engineering

Damage to or loss of craniofacial tissues, often resulting from neoplasm, trauma, or congenital defects, can have devastating physical and psychosocial effects. The presence of many specialized tissue types integrated within a relatively small volume leads to difficulty in achieving complete functional and aesthetic repair. Tissue engineering offers a promising alternative to conventional therapies by potentially enabling the regeneration of normal native tissues. Initially, a stimulus responsive biomaterial designed for injectable cell delivery applications was investigated with the goal of providing a substrate for osteogenic differentiation of delivered cells. In order to enable faster clinical translation, later efforts focused on novel combinations of regulated materials. Most common approaches using cell delivery for bone tissue engineering involve the harvest and ex vivo expansion of progenitor cell populations over multiple weeks and cell passages. The effect of aging and passage on proliferation and differentiation were analyzed using murine mesenchymal stem cells as a model. These cells lose their ability to proliferate and differentiate with increases in donor age and passages during cell culture. Delivery of uncultured bone marrow mononuclear cells was then investigated, and it was determined that when delivered to porous scaffolds these cells, which can be harvested, isolated, and returned to the body within the setting of a single operation, significantly increased bone regeneration in vivo. Finally, because these techniques of scaffold implantation and cell delivery would likely fail if delivered to an exposed or infected wound, a method of space maintenance was investigated. Space maintainers made of poly(methyl methacrylate) and having tunable porosity and pore interconnectivity were evaluated within a clean/contaminated mandibular defect. Low porosity space maintainers were found to prevent soft tissue collapse or contracture into the bony defect and allowed surrounding soft tissues to penetrate the pores of the implant, enabling healing over 12 weeks. The tissue response and wound healing characteristics of these implant was favorable when compared to solid or high porosity implants. Although optimization and further investigation of these techniques is necessary, in combination these approaches demonstrate one possible and translatable approach towards craniofacial tissue regeneration

DESIGN, DEVELOPMENT AND CHARACTERIZATION OF NOVEL BIOMATERIALS FOR PERIODONTAL TISSUE ENGINEERING

Periodontium is a complex system of different tissues, such as connective tissue, cartilage and bone, which work together to sustain the tooth. Gingivitis and periodontitis are devastating diseases that could affect the structure and function of the periodontal tissue. When the gingivitis are not treated and controlled with a correct oral hygiene, they could evolve in periodontitis, which could seriously damage the tissue surrounding the tooth and lead tooth loss. The main objective of periodontal tissue engineering is to regenerate the tooth’s supporting tissues. Periodontal tissue regeneration involves formation of new connective tissue (cementum and periodontal ligament) and new alveolar bone. The restoration of tooth by using a titanium dental implant is nowadays a quite common procedure. However, the positive fate of a surgical procedure that involves an insertion of titanium screw depends on the quality and quantity of alveolar bone which is present in the extraction site. The main objective of this doctoral thesis is to develop a set of novel biomaterials, designed to improve periodontal bone regeneration in patients and to control or prevent the bacterial infection in the wound site, via a sustained in situ drug release. Three different materials have been developed and characterized: 1. Three-dimensional porous scaffold coated with a polyelectrolyte complex for periprosthetic infection prevention 2. Bioceramic-reinforced hydrogel for alveolar bone regeneration 3. Antiadhesive guided tissue regeneration membrane The results demonstrated that they could be used in periodontal tissue engineering with predictable and excellent outcomes. With this set of biomaterials it is possible to control or prevent possible bacterial growth, achieve the correct alveolar bone quantity and quality and guide the tissue regeneratio