Saad Bin Qasim

Advances in Nanotechnology for Restorative Dentistry

Rationalizing has become a new trend in the world of science and technology. Nanotechnology has ascended to become one of the most favorable technologies, and one which will change the application of materials in different fields. The quality of dental biomaterials has been improved by the emergence of nanotechnology. This technology manufactures materials with much better properties or by improving the properties of existing materials. The science of nanotechnology has become the most popular area of research, currently covering a broad range of applications in dentistry. This review describes the basic concept of nanomaterials, recent innovations in nanomaterials and their applications in restorative dentistry. Advances in nanotechnologies are paving the future of dentistry, and there are a plenty of hopes placed on nanomaterials in terms of improving the health care of dental patients.

Freeze gelated porous membranes for periodontal tissue regeneration

Guided tissue regeneration (GTR) membranes have been used for the management of destructive forms of periodontal disease as a means of aiding regeneration of lost supporting tissues, including the alveolar bone, cementum, gingiva and periodontal ligaments (PDL). Currently available GTR membranes are either non-biodegradable, requiring a second surgery for removal, or biodegradable. The mechanical and biofunctional limitations of currently available membranes result in a limited and unpredictable treatment outcome in terms of periodontal tissue regeneration. In this study, porous membranes of chitosan (CH) were fabricated with or without hydroxyapatite (HA) using the simple technique of freeze gelation (FG) via two different solvents systems, acetic acid (ACa) or ascorbic acid (ASa). The aim was to prepare porous membranes to be used for GTR to improve periodontal regeneration. FG membranes were characterized for ultra-structural morphology, physiochemical properties, water uptake, degradation, mechanical properties, and biocompatibility with mature and progenitor osteogenic cells. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of hydroxyapatite and its interaction with chitosan. μCT analysis showed membranes had 85-77% porosity. Mechanical properties and degradation rate were affected by solvent type and the presence of hydroxyapatite. Culture of human osteosarcoma cells (MG63) and human embryonic stem cell-derived mesenchymal progenitors (hES-MPs) showed that all membranes supported cell proliferation and long term matrix deposition was supported by HA incorporated membranes. These CH and HA composite membranes show their potential use for GTR applications in periodontal lesions and in addition FG membranes could be further tuned to achieve characteristics desirable of a GTR membrane for periodontal regeneration.

Potential of electrospun chitosan fibers as a surface layer in functionally graded GTR membrane for periodontal regeneration

OBJECTIVE The regeneration of periodontal tissues lost as a consequence of destructive periodontal disease remains a challenge for clinicians. Guided tissue regeneration (GTR) has emerged as the most widely practiced regenerative procedure. Aim of this study was to electrospin chitosan (CH) membranes with a low or high degree of fiber orientation and examines their suitability for use as a surface layer in GTR membranes, which can ease integration with the periodontal tissue by controlling the direction of cell growth. METHODS A solution of CH-doped with polyethylene oxide (PEO) (ratio 95:5) was prepared for electrospinning. Characterization was performed for biophysiochemical and mechanical properties by means of scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, swelling ratio, tensile testing and monitoring degradation using pH analysis, weight profile, ultraviolet-visible (UV-vis) spectroscopy and FTIR analysis. Obtained fibers were also assessed for viability and matrix deposition using human osteosarcoma (MG63) and human embryonic stem cell-derived mesenchymal progenitor (hES-MP) cells. RESULTS Random and aligned CH fibers were obtained. FTIR analysis showed neat CH spectral profile before and after electrospinning. Electropsun mats were conducive to cellular attachment and viability increased with time. The fibers supported matrix deposition by hES-MPs. Histological sections showed cellular infiltration as well. SIGNIFICANCE The surface layer would act as seal to prevent junctional epithelium from falling into the defect site and hence maintain space for bone regeneration.

Chitosan Biomaterials for Current and Potential Dental Applications

Chitosan (CHS) is a very versatile natural biomaterial that has been explored for a range of bio-dental applications. CHS has numerous favourable properties such as biocompatibility, hydrophilicity, biodegradability, and a broad antibacterial spectrum (covering gram-negative and gram-positive bacteria as well as fungi). In addition, the molecular structure boasts reactive functional groups that provide numerous reaction sites and opportunities for forging electrochemical relationships at the cellular and molecular levels. The unique properties of CHS have attracted materials scientists around the globe to explore it for bio-dental applications. This review aims to highlight and discuss the hype around the development of novel chitosan biomaterials. Utilizing chitosan as a critical additive for the modification and improvement of existing dental materials has also been discussed.

Effect of calcium hydroxide on mechanical strength and biological properties of bioactive glass.

In this manuscript for the first time calcium hydroxide (Ca(OH)2) has been used for preparation of bioactive glass (BG-2) by co-precipitation method and compared with glass prepared using calcium nitrate tetrahydrate Ca(NO3)2·4H2O (BG-1), which is a conventional source of calcium. The new source positively affected physical, biological and mechanical properties of BG-2. The glasses were characterized by Fourier transform infrared (FTIR), X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA-DSC), BET surface area analysis and Knoop hardness. The results showed that BG-2 possessed relatively larger surface properties (100m(2)g(-1) surface area) as compared to BG-1 (78m(2)g(-1)), spherical morphology and crystalline phases (wollastonite and apatite) after sintering at lower than conventional temperature. These properties contribute critical role in both mechanical and biological properties of glasses. The Knoop hardness measurements revealed that BG-2 possessed much better hardness (0.43±0.06GPa at 680°C and 2.16±0.46GPa at 980°C) than BG-1 (0.24±0.01 at 680°C and 0.57±0.07GPA at 980°C) under same conditions. Alamar blue Assay and confocal microscopy revealed that BG-2 exhibited better attachment and proliferation of MG63 cells. Based on the improved biological properties of BG-2 as a consequent of novel calcium source selection, BG-2 is proposed as a bioactive ceramic for hard tissue repair and regeneration applications.

Electrospinning of Chitosan-Based Solutions for Tissue Engineering and Regenerative Medicine

Electrospinning has been used for decades to generate nano-fibres via an electrically charged jet of polymer solution. This process is established on a spinning technique, using electrostatic forces to produce fine fibres from polymer solutions. Amongst, the electrospinning of available biopolymers (silk, cellulose, collagen, gelatine and hyaluronic acid), chitosan (CH) has shown a favourable outcome for tissue regeneration applications. The aim of the current review is to assess the current literature about electrospinning chitosan and its composite formulations for creating fibres in combination with other natural polymers to be employed in tissue engineering. In addition, various polymers blended with chitosan for electrospinning have been discussed in terms of their potential biomedical applications. The review shows that evidence exists in support of the favourable properties and biocompatibility of chitosan electrospun composite biomaterials for a range of applications. However, further research and in vivo studies are required to translate these materials from the laboratory to clinical applications.

Influence of uncontrolled diabetes mellitus on periodontal tissues during orthodontic tooth movement: a systematic review of animal studies

Diabetes mellitus (DM) may adversely affect periodontal tissues during orthodontic tooth movement (OTM). The aim of this review is to systematically analyze and review animal studies investigating the effect of DM on periodontal tissues during OTM. An electronic search was conducted via PubMed/Medline, Google Scholar, Embase, ISI Web of Knowledge, and Cochrane Central Register of Controlled Trials (CONTROL) using the keywords “diabetes,” “orthodontics,” and “tooth movement” for studies published between January 2000 and August 2016. After elimination of duplicate items, the primary search resulted in 89 articles. After exclusion of irrelevant articles on the basis of abstract and title, full texts of 25 articles were read to exclude additional irrelevant studies. Seven animal studies were included in this review for qualitative analysis. When compared to healthy animals, more bone resorption and diminished bone remodeling were observed in diabetic animals in all studies. Furthermore, DM decreased the rate of OTM in one study, but in another study, DM accelerated OTM. DM may adversely affect bone remodeling and tooth movement during application of orthodontic forces. However, a number of potential sources of bias and deficiencies in methodology are present in studies investigating the association between OTM and DM. Hence, more long-term and well-designed studies are required before the exact mechanism and impact of DM on outcomes of orthodontic treatment is understood.

Influence of various bleaching regimes on surface roughness of resin composite and ceramic dental biomaterials

BACKGROUND Bleaching agents are commonly used in dentistry for treating the discolored teeth. A number of biomaterials and methods are in clinical applications. OBJECTIVE The major aim of this study was to evaluate the effects of two different bleaching agents on the surface roughness properties of dental resin nanocomposites and dental porcelains using various regimes. METHODS This study was conducted using direct restorative hybrid and nanocomposite materials and dental porcelains. The specimens were treated using the bleaching gels [(Opalescence Boost 40% OP) and (Whiteness HP 35% WHP)] for 30, 45, 60 and 120 minutes respectively. Treated samples were analyzed for surface roughness properties using contact mode surface profilometry and surface topography using scanning electron microscopy (SEM). Data was analyzed statistically using analysis of variance (ANOVA). RESULTS There were no significant changes observed in the roughness of nanofill, nanohybrid composites and ceramic materials compared to microhybrid resin composites (p> 0.05). The SEM photomicrographs confirmed the results of the profilometer showing slight changes in the microhybrid resin composite. CONCLUSIONS No remarkable difference was observed between the bleaching agents (Opalescence Boost and Whiteness HP Blue) for the surface roughness of tested dental materials. The bleaching agents can be used without harming the ceramic, nanofilled or nanohybrid resin restorations. However, if microhybrid or microfilled composite restorations are present in the oral cavity, bleaching may damage the surface finish and requiring replacement of restorations.

Application of Nanomaterials in Dentistry

Over the past few years, focus on the clinical application of nanobiomaterials in dentistry has been an area of interest to researchers worldwide. Nanotechnology is currently driving dental materials industry to substantial growth [1]. The advent of nanotechnology in dentistry seems to have answers to the mysteries or problems associated with conventional materials, as they have the tendency to mimic surface and interface properties of natural tissues. Nanotechnology has as a principle the ambitious challenge of precisely controlling individual particles in nanometer range. Some of the results are very relevant and have a major impact on human life and have already been adapted [2]. While the fields of tissue engineering and regenerative medicine have hinted at much promise over the last few decades, significant amount of research is still required with the field of nanotechnology to innovate new exciting materials that can overcome drawbacks of the existing biomaterials. Nanodentistry is still considered as an emerging field with a huge potential to yield new innovative generation of technologically advanced biomaterials in prosthodontics, orthodontics, periodontics, operatives, or restorative dental sciences. It is expected that nanodentistry will eventually give rise to highly efficient, effective, and personalized dental treatment [2].

Qualitative analysis of dental nano-composite restorative material using laser induced breakdown spectroscopy and EDS analysis

We have presented Analysis of UV irradiated dental nanocomposites restorative materials using laser-induced breakdown spectroscopy (LIBS). Samples of the materials are irradiated with UV light using 3M ESPE Elipar FreeLight2 Source. LIBS spectra of the samples are recorded using fundamental beam from Q-Switched Nd: YAG laser in conjunction with MS257 Spectrograph (Oriel instrument) equipped with Andor iStar ICCD camera. The emission spectra of these samples have been recorded as a function of laser irradiance. Traces of Titanium, Silicon, Aluminum, Strontium, Zirconium, Sodium and Calcium are detected in these samples. The elemental composition is found to be quite similar but the relative abundance of Zr and Si is higher in more UV exposed material. The samples have also been analyzed with SEM EDS for comparison.