Osteoblast response to titanium surfaces coated with strontium ranelate-loaded chitosan film.

PURPOSE: Improving the peri-implant bone quality has notable clinical value in cases of osteoporosis following implant insertion. MATERIALS AND METHODS: In this study, strontium ranelate-loaded chitosan film was produced on a titanium surface in different concentrations of strontium ranelate (SR) (0, 2, 20, 40, and 80 mmol/L of the strontium ion [Sr2+]) with the expectation of utilizing the bone healing-enhancement effect of Sr2+. The physicochemical properties of SR-loaded chitosan films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The release/dissolution mechanism was tested by inductively coupled plasma optical emission spectrometry (ICP-OES), and in vitro cell responses were evaluated using primary osteoblasts (POBs) in terms of cell proliferation, alkaline phosphatase (ALP) activity, and quantitative analysis of key osteoblastic gene expression. RESULTS: XRD and FTIR observation showed that only a few SRs reacted chemically with chitosan through hydrogen bonds or conjugate action. The initial burst release (70% to 85%) of Sr2+ occurred in the first 3 days and was followed by a slower release stage. At a low concentration (2 mmol/L or 20 mmol/L), SR-loaded chitosan film promoted cell responses of POBs with enhanced proliferation, ALP activity, and expression levels of bone morphogenetic protein 2 (BMP-2), runt-related transcription factor 2 (Runx-2), ALP, and osteocalcin, but at a high concentration (40 mmol/L or 80 mmol/L), it inhibited POB growth. CONCLUSION: These results indicated that SR-loaded chitosan film on a titanium surface promotes osteoblast proliferation and differentiation in a dose-dependent manner, which may represent a new approach in the treatment of a titanium implant.

Masticatory efficiency and oral health-related quality of life with implant-retained mandibular overdentures.

OBJECTIVES: To evaluate masticatory efficiency (ME) and oral health-related quality of life (OHRQoL) in patients rehabilitated with implant-retained mandibular overdentures. METHODS: In this randomized controlled clinical trial, 50 edentulous patients visiting the Implant Center and Department of Prosthodontics, West China College of Stomatology, Sichuan University, Chengdu, China between June 2010 and June 2012 were selected and received 2 implant-retained mandibular overdenture treatments. All patients were rehabilitated with maxillary complete dentures. The ME and OHRQoL were determined both one month before the mandibular complete denture was anchored to the osseointegrated implants, and 6 months after anchoring. Paired t-tests were used to compare means of ME, and oral health impact profile-49 (OHIP-49)  domains scores between pre- and post-implant. Linear regression models were utilized to seek correlations between ME and OHIP domains scores. RESULTS: The ME increased from pre- to post-implant retained mandibular overdentures significantly (p<0.001). The total OHIP score and 4 subscales scores were changed significantly from pre- to post-implant; namely, functional limitation, psychological discomfort, physical disability, and physical pain. The total OHIP score, functional limitation, physical disability, and physical pain subscale scores were related to ME. CONCLUSION: Implant-retained mandibular over dentures can significantly improve patients' ME and OHRQoL. The improvement in OHRQoL is mainly because of the improved ME. An improved chewing experience, and pain relief also contributes to improvement of OHRQoL. 

Single implant in the mandibular molar region of edentulous patient.

Implant-retained overdentures are a valid treatment option for edentulous patients, especially for patients with severe alveolar ridge atrophy. A central single implant is considered adequate to retain an overdenture in the edentulous mandible. However, for some patients, there is no sufficient bone height, or width in the interforaminal region of the mandible for insertion of the implant. This case report illustrates that the insertion of a single implant in the mandibular molar region might stabilize the prosthesis, and might improve the oral health-related quality of life and chewing function. A Locator attachment was used in this case to retain the overdenture. The one-year clinical results are promising. However, long-term clinical results and randomized clinical trials are needed before this method can be widely used in clinical application.

[Zoledronic acid incorporated in chitosan/calcium phosphate ceramic: characterization and in vitro response of osteoblast cells].

OBJECTIVE: To develop a new local delivery system, zoledronic-acid-loaded chitosan/calcium phosphate ceramic, and to determine its characterization and in vitro response of osteoblast cells. METHODS: Zoledronic-acid-loaded chitosan/calcium phosphate ceramic were prepared by solution casting method at a concentration of 10(-5), 10(-4), and 10(-3) mol/L, respectively. The physicochemical properties of the resulting materials were determined using SEM and FTIR. Drug absorbance was measured using CCK-8 colorimetric assay and alkaline phosphatase assay to detect the effect of drug-loaded materials on the proliferation and differentiation of osteoblasts. RESULTS: After ZOL loading, SEM showed that porous calcium phosphate ceramic was coated with chitosan evenly. The IR spectra indicated that drug absorption peaks were shifted and a new one was formed for the drug-loaded biomaterials. The material at the highest concentration could inhibit the proliferation and alkaline phosphatase activities of osteoblast cells, but no such effect was found at a drug-loading concentration of 10(-4)-10(-5) mol/L. CONCLUSION: We confirmed that the local delivery system in this study has ability of loading ZOL. The biomaterial with high drug concentrations inhibits the proliferation and differentiation of osteoblasts, but not when the drug concentrations are low.

[Construction and analysis of one kind of chitosan-coated BMP-2 nanoparticles as genetic carrier].

OBJECTIVE: To construct an excellent kind of chitosan-coated BMP-2 nanoparticles as genetic carrier. METHODS: Chitosan-coated BMP-2 nanoparticles as genetic carrier, including C-B50 group, C-B100 group and C-B200 group, were constructed through re-coacervation and gene recombination methods. This carrier was studied by using morphological observation, enveloping test, anti- DNase I digested test and MTT assay. RESULTS: One kind of excellent chitosan-coated BMP-2 nanoparticles as genetic carrier was constructed. Particle diameter was about (90 +/- 20) nm. Enveloping ratio of C-B50 group, C-B100 group and C-B200 group was 76.31% + 1.58%, 84.49% + 1.81% and 81.69% + 1.77%, respectively. Genetic carrier could prevent objective gene from DNase I digestion. The growth inhibiting ratio to bone marrow stem cells was increased as the increase of genetic carrier dose and contact time (P < 0.05), but maximal dose of carrier had no obvious toxic effect on cells growth in vitro. CONCLUSION: The constructed chitosan-coated BMP-2 nanoparticle material was a promising genetic carrier in bone tissue engineering.

[The investigation patients' general knowledge about artificial teeth prosthetics].

OBJECTIVE: To get the information of patients' understand to the knowledge of artificial teeth prosthetics, provide reference for the propaganda of the prosthetic knowledge. METHODS: 500 patients were chosen as the research objects. The survey about patients' understand to the knowledge of artificial teeth prosthetics was made with a reasonable questionnaire designed by us. The questionnaire contained nine sections. The questionnaires were filled in by the patients, dispatched and received by special messengers. The information of the questionnaires was analyzed and summarized. RESULTS: 477 effective questionnaires were received. Patients were more familiar with the knowledge of the opportunity to get the oral prosthetic and less familiar with the knowledge of common problems after the oral prosthetic, the curing process before the oral prosthetic and the visiting times of the ordinary cure. However, they were not familiar with the knowledge of the basic concepts of the oral prosthetic, prosthetic materials and construction of dental prosthetic restoration and announcements after the oral prosthetic. They were most unfamiliar with the knowledge of common problems in the oral prosthetic process. CONCLUSION: The propaganda of the oral prosthetic should focus on the basic concepts of the oral prosthetic, prosthetic materials and construction of dental prosthetic restoration, common problems in the oral prosthetic process and announcements after the oral prosthetic. Meeting such problems, dentists should explain them to the patients patiently.