Periodontal Applications Research Articles

Pluronic and Chitosan basedIn situgel system for periodontal application

Pluronic and Chitosan based<i>In situ</i>gel system for periodontal application

Tetracycline release from tripolyphosphate–chitosan cross‐linked sponge: a preliminary in vitro study

The aim of this study was to design a tripolyphosphate-chitosan cross-linked tetracycline-containing (TPP-TC) sponge that slowly releases tetracycline, for future periodontal applications. Chitosan sponge was made by freezing and drying 2.5% chitosan solution. Tripolyphosphate-chitosan cross-linked (TPP) sponge was made by immersing the chitosan sponge in tripolyphosphate solution and air drying it. Tetracycline-containing chitosan (TC) sponge was prepared by freezing and drying a mixture of chitosan and tetracycline. TPP-TC sponge was made by immersing the TC sponge in tripolyphosphate solution. The weight, thickness and diameter of the four chitosan sponges were recorded. Their surface microstructures were inspected using scanning electron microscopy. The amount of tetracycline released from the sponges was analyzed by spectrophotometry. Antimicrobial activities of the residual sponges were tested against Staphylococcus aureus and Escherichia coli. The topography of the scaffolds was intact after the addition of tetracycline. However, increased surface irregularities were noted. In sponges with tripolyphosphate, intensified surface folding was observed. The weight of the sponges increased after tripolyphosphate and tetracycline were added, but their thicknesses and diameters decreased after cross-linking. Tetracycline was detected in the solution containing TPP-TC sponges until day 11. On day 7, the tetracycline released from TC sponges was less than that released from TPP-TC sponges. Bacterial growth was inhibited by sponges containing tetracycline. The inhibitory effect of the TPP-TC sponges was detectable until day 11. Our data showed that TPP-TC sponge was suitable as a slow-release device for tetracycline and that it maintained antimicrobial effects against the bacteria tested for up to 11 d.

Acceleration of de novo bone formation with a novel bioabsorbable film: a histomorphometric study in vivo

Different types of barrier membranes have been used in periodontal applications for the technology of guided tissue regeneration (GTR). The aim of this study was to characterize the biological effect of novel calcium alginate film (CAF) on bone tissue regeneration by using rabbit mandible defects model. A critical size defect (5 mm in diameter) was created in the bilateral corner of mandible of 45 adult rabbits. The defects were covered with CAF served as the experimental group, or conventional collagen membrane (CCM) or left empty as the controls. Animals were killed after 1, 2, 4, 6 and 8 weeks. Morphological and histomorphometric studies were performed to evaluate their bone regeneration pattern and biological effects. Histological sections showed that bone regeneration pattern was centripetal in growth from defect rim. The quantitative histometry analysis revealed a significantly greater percentage of newly generated bone in CAF defects than that in CCM defects and empty defects from 2 to 6 weeks post-operation (P < 0.01). After 6 and 8 weeks, significantly more mature lamella bone had formed with CAF than with CCM. Empty control defects showed bone formation starting from the defect margins and incomplete healing even after 8 weeks. The CAF guided early bone growth and appeared more effective as a bioabsorbable GTR membrane than CCM. This study with mandible defect model suggests that bone defects augmented with CAF may offer most promising results from a histological and histomorphometric perspective.

Bone morphogenetic proteins in tissue engineering: the road from laboratory to clinic, part II (BMP delivery)

Bone morphogenetic proteins (BMPs) are cytokines with a strong effect on bone and cartilage growth and with important roles during embryonic patterning and early skeletal formation. BMPs have promising potential for clinical bone and cartilage repair, working as powerful bone-inducing components in diverse tissue-engineering products. Synthetic polymers, natural origin polymers, inorganic materials and composites may be used as carriers for the delivery of BMPs. Carriers range from nanoparticles to complex three-dimensional (3D) scaffolds, membranes for tissue-guided regeneration, biomimetic surfaces and smart thermosensitive hydrogels. Current clinical uses include spinal fusion, healing of long bone defects and craniofacial and periodontal applications, amongst others. BMP-2 and BMP-7 have recently received approval by the US Food and Drug Administration (FDA) for specific clinical cases, delivered in absorbable collagen sponges. Considering the expanding number of publications in the field of BMPs, there are prospects of a brilliant future in the field of regenerative medicine of bone and cartilage with the use of BMPs.

Microfabricated Discontinuous-Edge Surface Topographies Influence Osteoblast Adhesion, Migration, Cytoskeletal Organization, and Proliferation and Enhance Matrix and Mineral Deposition In Vitro

The fabrication of surfaces that stimulate increased adhesion, migration, and differentiated function of osteoblasts has been viewed as being desirable for many orthopedic applications. Previous studies have shown that microfabricated pits and grooves alter adhesion, spreading, matrix secretion, and production of mineral by rat calvarial osteoblasts (RCOs). The mechanisms underlying these effects are unknown, although microenvironment and cell alignment are considered to play a role. The aim of this work was to investigate the behavior of RCOs on microfabricated discontinuous-edge surfaces (DESs), which could provide an alternative means to control both the microenvironment and cellular alignment. Two types of discontinuous-type structures were employed, gap-cornered boxes and micron scale pillars. DES gap-cornered boxes and the pillars influenced the arrangement of F-actin, microtubules, and vinculin. Osteoblasts were guided in their direction of migration on both types of substrata. Both box DESs and pillars altered the staining intensity and localization pattern of phosphotyrosine and src-activated FAK localization. Cell multilayering, matrix deposition, and mineralization were enhanced on both discontinuous topographies when compared with smooth controls. This study shows that DESs alter adhesion, migration, and proliferative responses from osteoblasts at early time points (<1 week) and promote multilayering, matrix deposition, and mineral deposition at later times (2-6 weeks). Such topographical patterns could potentially be employed as effective surface features on bone-contacting implants or in membrane-based periodontal applications.

Possibility of clinical usage of BMP in periodontal application; basic study

It is necessary for using some carriers which hold bone morphogenetic protein (BMP) activity and maintain its osteoinductive ability, when BMP is applied to the tissue regeneration of the bone defect caused by periodontal diseases. It is indispensable for using some carriers which hold BMP activity and maintain its osteoinductive ability, when BMP is applied to the tissue regeneration of the bone defect caused by the diseases. Metals, ceramics and polymers are used for such carriers, and especially, polymers are indispensable. It is also important to prevent the penetration of epithelial tissue downgrowth, therefore, we innovated a noble resin material which can be formed to the thin film and has a property of light curing. Composite of this resin and BMP stably induced new bone. Cartilage induction in the organ culture on the artificial membrane was also succeed, and it will extend to the bone regeneration by means of re-transplantation of patient's derived tissues after the incubation.

Orthodontic Extrusion: Periodontal Considerations and Applications

Orthodontic Extrusion: Periodontal Considerations and Applications

A PLGA membrane controlling cell behaviour for promoting tissue regeneration

Barrier membranes are used in periodontal applications with the aim of supporting bone regeneration by physically blocking migrating epithelial cells. We report a membrane design that has a surface topography that can inhibit epithelial cell migration and proliferation on one side and a topography that guides osteoblast migration to a desired area. A PLGA copolymer (85:15) blended with MePEG, was cast to have surfaces with smooth, grooved or sandblasted-acid-etched topographies. Epithelial cells spread on smooth surfaces after 24 h, and cell numbers increased after 5 days. Cells on the smooth surface exhibited no preferred direction of migration. On the sandblasted-acid-etched topography epithelial cells spread but the cell number did not significantly increase after 5 days. Cell migration was inhibited on this surface. Osteoblasts spread on both grooved and smooth surfaces and cell number increased after 5 days on all surfaces. The cells that adhered in the grooves migrated preferentially in the direction of the grooves. Positive alkaline phosphatase staining was seen on all surfaces within 4 weeks and positive Von Kossa nodule staining within 6 weeks. These results suggest that surface topographies replicated on opposite sides of a biodegradable polymers membrane can inhibit proliferation and migration of the epithelial cells, and promote proliferation and directional migration of osteoblasts. Addition of appropriate surface topographies to membranes used in guided tissue regeneration has the possibility of improving clinical performance in periodontal tissue regeneration procedures.

Evaluation of the Safety and Efficacy of Periodontal Applications of a Living Tissue‐Engineered Human Fibroblast‐ Derived Dermal Substitute. II. Comparison to the Subepithelial Connective Tissue Graft: A Randomized Controlled Feasibility Study

The subepithelial connective tissue graft, traditionally harvested from the patient's palate, is commonly used for root coverage in periodontal recession defects. This study evaluates the safety and effectiveness of a living human fibroblast-derived dermal substitute (HF-DDS) compared to a connective tissue graft (CTG) for root coverage in these situations. Thirteen patients were selected for this study. Each patient had Miller Class I or II bilateral facial recession defects > or =3 mm on two non-adjacent teeth. The test tooth received an HF-DDS graft, while a CTG was placed on the control site. The 10 test surgeries were performed by one operator and three pilot surgeries were performed by another surgeon. Eight of the HF-DDS sites received a single thickness of material; five received a double thickness. Clinical measurements were taken at baseline; 1 week; and 1, 3, and 6 months following surgery. Parameters measured were plaque index, recession depth, clinical attachment levels, recession width, probing depth, and width of keratinized tissue. All clinical readings were taken by a masked, calibrated examiner. There were no statistically significant differences between the test and control groups. The amount of root coverage was slightly greater for the control group than for the test group, but statistically the difference was insignificant. The width of the recession defect measured at the cemento-enamel junction (CEJ) for the test group was slightly smaller than that of the control group at the conclusion of the study. The amount of keratinized tissue was the same in both groups at 6 months. The probing depth was slightly greater in the control group as was the gain in clinical attachment, but neither was statistically significant. The amount of root coverage obtained when one layer of HF-DDS was used compared to the amount of coverage obtained when two layers were used approached statistical significance, but the small sample size may have been responsible for the difference. Within the limits of this study, the human fibroblast-derived dermal substitute may offer potential as a substitute to the connective tissue graft for covering areas of facial Miller Class I or Class II gingival recession in humans.

Evaluation of the Safety and Efficacy of Periodontal Applications of a Living Tissue‐Engineered Human Fibroblast‐Derived Dermal Substitute. I. Comparison to the Gingival Autograft: A Randomized Controlled Pilot Study

Periodontists have found the gingival autograft to be an effective and predictable technique to increase the amount of attached gingiva around teeth, but this technique requires the surgeon to harvest donor tissue from a remote surgical site. The present study seeks to evaluate the safety and effectiveness of a tissue-engineered skin equivalent, a living human fibroblast-derived dermal substitute (HF-DDS), compared to a gingival autograft (GA) consisting of donor tissue harvested from the patient's palate in a procedure designed to increase the amount of keratinized tissue around teeth that do not require root coverage. Twenty-five patients with insufficient attached gingiva associated with at least two teeth in contralateral quadrants of the same jaw were treated. One tooth in each patient was randomized to receive either a GA (control) or a HF-DDS graft (test). Clinical parameters measured at baseline and 3, 5, 7, 9, and 12 months included recession, clinical attachment level, keratinized tissue height, and plaque index. Probing depth was measured at 7, 9, and 12 months. Inflammation of each site was scored and texture and color of the grafted tissue were compared to the surrounding tissue. Resistance to muscle pull was evaluated and a questionnaire was used to determine patient preference. Surgical position of the graft and alveolar bone level were recorded at the surgical visit and patients were evaluated weekly for the first 4 weeks at which time recession and level of oral hygiene were measured. Biopsies and persistence studies were performed on a subset of the patients. Results for both test and control groups were similar for all measured clinical parameters with the exception of amount of keratinized tissue and percent shrinkage of keratinized tissue. The control group exhibited an average of 1.0 to 1.2 mm more keratinized tissue over time than the test group (P <0.001) and the control group had about half as much shrinkage as the test group over time (P <0.001). Test sites demonstrated significantly better color match over time compared to control sites. Similarly, tissue texture for test sites was significantly better than control sites over time. Based on the results of this investigation, the tissue engineered HF-DDS graft was safe and capable of generating keratinized tissue without the morbidity and potential clinical difficulties associated with donor site surgery. The GA generated more keratinized tissue and shrank less than the HF-DDS graft, but the test graft generated tissue that appeared more natural.

Bioactivity of diopside ceramic in human parotid saliva

Diopside ceramic pellets with a nominal composition of 55.5 wt % SiO(2)-25.9 wt % CaO-18.0 wt % MgO were soaked in human parotid saliva (HPS) over different time intervals, to investigate the behavior of the material in a natural medium of high protein content. The results showed the formation of a hydroxyapatite (HA)-like layer on the surface of the ceramic, and suggested that the mechanism of HA-like layer formation in saliva was similar to that showed in vitro test by other silica-based materials. The HA-like layer formed at the interface was found to be compact, continuous, and composed of many small crystallites with ultrastructure similar to that of natural cortical bone and dentine. The study concluded that the high pH conditions (9.8) existing right at the ceramic/human parotid saliva interface promoted HA-like phase precipitation. At this stage of the study, it is possible to suggest that the diopside ceramic could be of interest in specific periodontal applications for bone restorative purposes. Morphology, structure, and composition of the interfacial reaction product were examined by Scanning and Transmission Electron Microscopy techniques (SEM and TEM), combined with Energy Dispersive X-say Spectroscopy (EDS). Changes in ionic concentrations were measured using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), while the pH right at the interface of diopside/PHS were determined with an Ion Sensitive Field Effect Transistor (ISFET-Meter) instruments.

Nanoparticulate Hydroxyapatite Enhances the Bioactivity of a Resorbable Bone Graft

ABSTRACTA nanoparticulate-hydroxyapatite filler augmented osteointegration within a resorbable polymer based bone graft substitute designed for orthopaedic and periodontal applications. The unsaturated polyester poly(propylene glycol-co-fumaric acid) (PPF), was used to prepare the bone graft substitute. The nanoparticulate-hydroxyapatite filler was examined in terms of biocompatibility, bony ingrowth and mechanical stability in a rat calvarial defect model. The nano-hydroxyapatite fillerwas compared against a commercially available micrometer-sized hydroxyapatite(HA) filler. Histological analysis indicated that remodeling of the newly formed bone was more advanced in the defect filled with the nano-hydroxyapatite augmented PPF. Mechanical evaluation showed a more rapid increase in stiffness of the nano-hydroxyapatite PPF. Implants of the nano-HA augmented PPF showed more advanced bone formation and recovery of mechanical properties, suggesting an improved biological response to the nano-sized particles.

Bioactivity of pseudowollastonite in human saliva

Objectives: Pseudowollastonite (CaO·SiO 2) was found to be bioactive in a simulated body fluid environment. In the present study, `in vitro' bioactivity of pseudowollastonite was further assessed in human parotid saliva. The main objective was to compare behaviour of the material in a natural medium of high protein content (human parotid saliva) with its behaviour in an acellular protein-free solution (simulated body fluid). Methods: Samples of polycrystalline pseudowollastonite were immersed for one month in human parotid saliva at 37°C. Changes in ionic concentrations in the human parotid saliva and the pH right at the interface of pseudowollastonite/human parotid saliva were determined. The products of the interfacial reactions were studied by thin-film X-ray diffraction, scanning and transmission electron microscopy. Results: The results confirmed formation of a hydroxyapatite-like layer on the surface of the material, and also suggested that the mechanism of hydroxyapatite-like layer formation in saliva was similar to that showed in simulated body fluid. Conclusions: The hydroxyapatite-like layer formed at the interface was found to be compact, continuous and composed of many small crystallites with ultrastructure similar to that of natural cortical bone and dentine. The study also concluded that the high pH conditions (10.32) existing right at the pseudowollastonite/human parotid saliva interface promoted hydroxyapatite-like precipitation. At this stage of the study, similarities of the material behaviour in saliva and acellular simulated body fluid suggest that the pseudowollastonite could be of interest in specific periodontal applications for bone restorative purposes.

Controlled release of platelet-derived growth factor from porous poly( l-lactide) membranes for guided tissue regeneration

Platelet-derived growth factor-BB (PDGF-BB) was incorporated into porous poly ( l-lactide) (PLLA) membranes with an aim of improving early bone healing in guided tissue regeneration (GTR) therapy. Porous PDGF-BB loaded membranes were fabricated by coating PDGF-BB-dissolved PLLA methylene chloride–ethyl acetate solutions on polyglycolic acid (PGA) meshes. Release kinetics of PDGF-BB, biologic activity, degradability and guided tissue regenerative potentials of the membranes were investigated. Release of PDGF-BB could be controlled by adding bovine serum albumin that may provide porous diffusion channels for PDGF-BB release and by varying initial loading content of PDGF-BB. Biologic activity of PDGF-BB in the membranes was ascertained by fibroblast chemotaxis. PDGF-BB loaded membranes maintained proper degradation property for periodontal application. PDGF-BB loaded membrane markedly increased new bone formation in rat calvarial defects, and completed bony reunion after 2 weeks of implantation period. These results suggested that PDGF-BB loaded PLLA membrane might potentially enhance guided tissue regenerative efficacy.

Interactions between Bioactive Glass and Periodontal Pathogens

Bioactive glasses have been used in periodontal applications such as grafting infrabony periodontal lesions. We studied a bioactive glass S53P4 for its possible antibacterial effects on the periodontal pathogens Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans using agar plate tests. Also the colonisation of the bioactive glass with these microorganisms was studied by incubating bacterial suspensions with glass granules. Two precorrosion procedures were used to create chemically differing surfaces on the bioactive glass. The bioactive glass did not alter the growth properties of any of the tested microorganisms. P. intermedia and A. actinomycetemcomitans showed adherence both to the untreated and precorroded bioactive glasses. However, P. gingivalis adhered only to the precorroded glasses and was agglutinated in the presence of the untreated glass. Coating the untreated glass with serum or Actinomyces viscosus cells did not eliminate the agglutination. Thus, even though the bioactive glas S53P4 did not alter the growth properties of the studied microorganisms it may in vivo beneficially modify the microbiota of periodontal lesions by agglutinating P. gingivalis. Keywords: Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, Actinomyces viscosus , bioactive glass, corrosion.

Interactions between Bioactive Glass and Periodontal Pathogens

Bioactive glasses have been used in periodontal applications such as grafting infrabony periodontal lesions. We studied a bioactive glass S53P4 for its possible antibacterial effects on the periodontal pathogens Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans using agar plate tests. Also the colonisation of the bioactive glass with these microorganisms was studied by incubating bacterial suspensions with glass granules. Two precorrosion procedures were used to create chemically differing surfaces on the bioactive glass.The bioactive glass did not alter the growth properties of any of the tested microorganisms. P. intermedia and A. actinomycetemcomitans showed adherence both to the untreated and precorroded bioactive glasses. However, P. gingivalis adhered only to the precorroded glasses and was agglutinated in the presence of the untreated glass. Coating the untreated glass with serum or Actinomyces viscosus cells did not eliminate the agglutination. Thus, even though the bioactive glas S53P4 did not alter the growth properties of the studied microorganisms it may in vivo beneficially modify the microbiota of periodontal lesions by agglutinating P. gingivalis.

Preventive Dental Materials: Sustained Delivery of Fluoride and Other Therapeutic Agents

In the 1940's, it was observed that silicate restorative cements were seldom associated with secondary caries. Fissure sealants, designed to protect caries-prone surfaces, appeared in the 1960's. The 1970's and 1980's have seen an increasing emphasis on the use of dental materials for preventive purposes. Glass ionomers, the modern version of silicates, release fluoride and have been available for some time. Polymeric materials that release various therapeutic agents are currently under development for use in topical anesthetic, endodontic, prosthodontic, and periodontal applications. An attachable membrane-reservoir device for oral fluoride delivery will soon be available for general clinical use. Several fluoride-releasing filling and adhesive resins have recently been marketed. These materials are the leading edge of a new class of preventive materials that serve as controlled-release and/or site-specific sources of therapeutic agents. This trend is expected to continue, and the near future should see the introduction of additional oral sustained-delivery systems for use in periodontal and other applications.

A Contemporary Perspective on Techniques for the Clinical Assessment of Alveolar Bone

Radiographic techniques, traditional ones as well as newer ones under development, for clinically assessing alveolar bone are critically assessed. Traditional intraoral radiography is reexamined, in particular with regard to the accuracy with which the alveolar crest is seen. Evidence is presented for a more accurate representation of the alveolar crest on bitewings rather than periapical films. Application in periodontics of newer radiographic techniques, subtraction radiography, and single and dual photon aborptiometry presently under clinical development are discussed in regard to their potential and limitations. Similarly, radiopharmaceuticals to evaluate the metabolic status of alveolar bone are discussed as well as the potential for using analyses of gingival crevice fluid as a window for assessment of alveolar crest metabolism.