pH-responsive poly(lactide-co-glycolide) nanoparticles containing near-infrared dye for visualization and hyaluronic acid for treatment of osteoarthritis.

This study focuses on intra-articular (IA) drug delivery system for the treatment of knee osteoarthritis (OA). In osteoarthritic condition the synovial fluid presents pockets with lower pH environment. To take advantage of these pH differences, poly(lactic-co-glycolic acid (PLGA) nanoparticles (NPs) and pH- responsive PLGA NPs encapsulated with ammonium bicarbonate (NH4HCO3) were generated. The nanoparticles were loaded with hyaluronic acid (HA) as a possible model drug for OA and with near-infrared dye (NIR) that was used to visualize the NPs with molecular imaging techniques. These NPs were characterized by dynamic light scattering, transmission electron microscopy and compared in in vitro, in vivo and ex vivo experiments in the treatment of OA. The results indicate that the NPs were sufficiently small, displayed a uniform size distribution and were non-toxic both in vitro and in vivo. Both NPs treatment seem to induced a reduction in OA progression, with pH- responsive NPs showing the more pronounced effect. This is probably because the pockets of low pH environment in the synovial fluid trigger a burst release of the pH-responsive NPs. This result is corroborated by in vitro experiments since the pH- responsive NPs showed an extracellular burst release behavior and higher chondrocyte vitality than non-responsive NPs. This study demonstrates that PLGA NPs containing HA and NH4HCO3 are candidates for the treatment of knee OA.

Qualitative characterization of a transesterification product of coconut oil by FIA-APCI-MS.

OBJECTIVES: The purpose of this work was the qualitative characterization of a recently transesterification product obtained from the coconut oil in the presence of polyglycerol-6 to produce a new PEG-free secondary surfactant. The purpose of a secondary surfactant is to reduce the harshness of a skin cleanser. METHODS: The transesterification product was qualitatively characterized in our laboratory by flow injection analysis-atmospheric pressure chemical ionization-mass spectrometry (FIA-APCI-MS). The mass spectrum of the transesterification product was compared to those of the starting materials (polyglycerol and coconut oil). RESULTS: The analyses highlighted the disappearance of the starting oil peaks and the appearance of new peaks assignable to the reaction products, mainly corresponding to diesters of polyglycerol. Additionally, peaks of unreacted polyglycerol are present as well as peaks of cyclization products derived from the polyglycerol starting material. CONCLUSIONS: The development of this fast and easy analytical method, requesting only few minutes to be performed, represents a very useful tool for the characterization of transesterification products during the quality control of batches under production.

Large buccal bifurcation cyst in a child: a case report and literature review.

BACKGROUND: WHO defines the mandibular buccal bifurcation cyst as a cyst occurring near the cervical margin of the lateral aspect of a root as a consequence of inflammatory process in a periodontal pocket. The pathogenesis of these cysts is still debated, but they are most likely originated from reduced enamel epithelium or from inflammatory proliferation of epithelial cell rests of Malassez that come from the superficial mucosa of a tooth in eruption. The aim of this article was to describe a case of large buccal bifurcation cyst of a permanent mandibular first molar. CASE REPORT: A 6-year-old boy was referred to Department of Oral Riabilitation of the Istituto Stomatologico Italiano, University of Milan, Italy, with the complaint of hard swelling over the buccal gingiva and a deep probing depth located on the buccal aspect. Radiograph revealed a well-defined semilunar-shaped radiolucency, marked by a fine radiopaque line on the buccal aspect of the partially-erupted lower right first molar and it was large enough to include a small part of the crown of the second right molar. As reported in the literature the treatment of choice is enucleation and curettage of the lesion without extraction of the vital involved tooth. This procedure has shown excellent results in both the short- and long-term. The definitive diagnosis of paradental cysts can be assessed by histopathologic analysis.

Treatment of seriously compromised teeth: decision- making criteria and treatment options.

The aim of this article was to describe the case of a patient who presented to our attention with severe periodontal disease, complicated by furcation involvement on elements 16 and 17. In addition, the radiographic exam revealed the presence of a deep intrabony defect distal to tooth 15. Surgical therapy is performed after the resolution of the endodontic component of the intra-bony defect on the element 15 and consists on osteoplasty and ostectomy on 16, guided tissue regeneration (GTR) on 15, extraction of 17 and bi-laminar connective tissue graft for the coverage of the recession on tooth 13. The patient is visited monthly and 9 months after surgery, the definitive metal-ceramic crown is delivered and adapted to tooth 16. At 18 months, the patient's periodontal situation is re-evaluated and the pocket depth results healthy (probing depth of tooth 15=2 mm). The surgical practices reported in this work allowed for functional and esthetic rehabilitation of periodontally compromised teeth. The RSR and the GTR represent conservative surgery that allow the preservation of compromised dental elements and if properly performed, guarantee excellent survival rates of the elements in the arch. For these reasons, when it is possible, the RSR and the GTR are a valid alternative to implantology and are to be considered as the first therapeutic option in the treatment plan.

Behavior of endosseous one-piece yttrium stabilized zirconia dental implants placed in posterior areas.

AIM: Considering that zirconia dental implants are indicated for the rehabilitation of highly esthetic areas, the aim of this work was to investigate the functional behavior of these implants positioned in the posterior regions of the jaws. METHODS: The study included 6 patients with 14 zirconia implants positioned in posterior (molar) areas of the jaws. Immediately after surgery, all implants were restored with temporary crowns or bridges. Clinical radiographic evaluation was performed 6 months after surgery and subsequently every year. At these follow-up visits, periodontal indexes were recorded and peri-apical radiographs were taken in order to calculate marginal bone loss. RESULTS: The success and survival rates were 100%. The modified bleeding index (mBI) and modified plaque index (mPLI) were respectively equal to 0.57±0.51 and 0.29 ± 0.47 at 4-year follow-up. The overall mean probing depth of the implants was 3.13±0.87 mm. The mean marginal bone loss was +0.665 mm 4 years after surgery. CONCLUSION: Considering the limits of our study, as regards to the data concerning peri-implant tissue health, marginal bone loss and survival and success rates of zirconium implants placed in posterior areas, we can conclude that the data reported are very encouraging although the number of implants observed is still limited.

Minimally invasive surgical approach in a large mandibular solitary cyst: case report and review of the literature.

Solitary bone cyst (SBC) is an intraosseus radiolucent lesions that defers from real cysts for the fact that peripheral epithelial lining is totally absent. It could be classified as a psudocyst and occurs most frequently in young patients. In most cases SBC doesn't cause symptoms and it is often diagnosed accidentally during routine radiographic examination. A right diagnosis of this disease is also complicated because there are no pathognomonic radiographic signs and symptoms: so this form of pseudocyst is often misdiagnosed as a common odontogenic cyst. Despite numerous studies, the pathogenesis of the SBC is not yet established: the most widely accepted theory is that it could be the result of an intramedullary necrosis determined by a trauma. In this article we report a case of SBC in child treated with a minimal surgical approach. This new kind of treatment is much more conservative than the traditional one, it can be performed as outpatients, under local anesthesia and with few postoperative discomfort: For these reasons this minimal invasive technique appears to be particulary suitable for pediatric patients.

Use of endosseous one-piece yttrium-stabilized zirconia dental implants in premolar region: a two-year clinical preliminary report.

AIM: The aim of this work was to clinically and radiographically evaluate survival and success rate of zirconia dental implants positioned in premolar area during a follow-up period of at least 12 months up to 24 months. METHODS: Sixteen patients were treated with 26 zirconia implants. All implants received immediate temporary restorations and 6 months after surgery were definitively restored. Twelve to 14 months after implant insertion, a clinical-radiographical evaluation was performed in order to estimate peri-implant tissues health and peri-implant marginal bone loss. RESULTS: The survival rate was 96.16%. The success rate was 91.6%. CONCLUSION: Because of the limited number of implants, conclusions may not be considered significant even if results are encouraging. Further scientific information regarding clinical use of zirconia dental implants are needed, as well as prospective long-term clinical studies in order to understand if zirconia implants may represent a valid alternative to titanium implants.

Edentulous jaws rehabilitation with yttrium-stabilized zirconium dioxide implants: two years follow-up experience.

AIM: The aim of this study was to present authors' two-year clinical experience with Yttrium-stabilized zirconium dioxide implants placed in native bone or regenerated bone. METHODS: Yttrium-stabilized zirconium dioxide implants made of brezirkon (whiteSKY, Bredent medical, Senden, Germany) were used for the treatment of edentulous ridge rehabilitation in the Dental Clinic of the University of Milan (Head of the Department, Prof. F. Santoro). Zirconium dioxide is a highly resistant ceramic material obtained by cleaning zirconium dioxide and zirconium silicate. The implant used in the clinical study featured a conical one piece implant with double cylindrical thread with a sandblasted rough surface. The prosthetic section was smooth. RESULTS: Forty-six implants have been inserted in 18 patients from January 2007 to January 2009, the follow-up period was comprised between 6 and 24 months. The overall success rate was 89%; the success rate in native bone was 97% and 74% in augmented bone. It can be stated that the success rate is comparable to titanium fixtures. CONCLUSION: It would be logical to use a ceramic material for the esthetic regions; zirconium dioxide is particularly suitable since it features tissue friendliness and resistance comparable to titanium. The good mechanical properties, possibility of easy fabrication of the prosthetic restoration and the good integration into the tissue and the esthetics provide perfect preconditions for yttrium-stabilized zirconium dioxide to become the most commonly used material in implant dentistry.

Displacement of a dental implant into the maxillary sinus: case series.

Dental implants placed in the maxilla risk failure because of the low density of the maxillary bone and the shortness of the maxillary ridge. Moreover, inadequate implant preparation, drilling or installation can easily lead to complications related to the maxillary sinuses. Displacement of dental implants into the maxillary sinus can cause serious complications, but there are few reports of such cases. The aim of this paper is to present three cases of a migrated dental implants into the maxillary sinus: in the first two cases the dental implant was found close to the medial wall of the maxillary sinus and was removed through a surgical approach, whereas in the third case the dental implant was spontaneously expelled from the nasal cavities through the mucociliary clearance. The most frequent adverse effect is the local infection of tissue around the implant. For this reason, implants placed close to the maxillary sinus offer a route for infection from the oral cavity to the sinus. While in some cases implant migration causes sinusitis in other, the patients remain asymptomatic; anyway, the treatment depends on the symptoms of maxillary sinusitis. In the third case the dental implant was spontaneously expelled from the nasal graves. Our report illustrates that a powerful mechanism of mucociliary action can cause relatively heavy objects within the maxillary sinus to migrate naturally to the sinus ostia against gravitational force and then to be expelled from the nasal cavities.

Photopolymerized thermosensitive hydrogels for tailorable diffusion-controlled protein delivery.

In this paper the possibility to tailor degradation and protein release behavior of photopolymerized thermosensitive hydrogels is studied. The hydrogels consist of ABA triblock copolymer, in which the thermosensitive A-blocks are methacrylated poly(N-(2-hydroxypropyl)methacrylamide lactate)s and the B-block is poly(ethylene glycol) with molecular weight of 10 kDa. These hydrogels are prepared by using a combination of physical and chemical cross-linking methods. When a solution of a thermosensitive methacrylated p(HPMAm-lac)-PEG-p(HPMAm-lac) is heated above its cloud point a viscoelastic material is obtained, which can be stabilized by introducing covalent cross-links by photopolymerization. By varying the polymer concentration, hydrogels with different mechanical properties are formed, of which the cross-linking density, mesh size, swelling and degradation behavior can be tuned. It was demonstrated that the release rate of three model proteins (lysozyme, BSA and IgG, with hydrodynamic diameters ranging from 4.1 to 10.7 nm) depended on the protein size and hydrogel molecular weight between cross-links and was governed by the Fickian diffusion. Importantly, the encapsulated proteins were quantitatively released and the secondary structure and the enzymatic activity of lysozyme were fully preserved demonstrating the protein friendly nature of the studied delivery system.