Enhancement of osteoblast proliferation in vitro by selective enrichment of demineralized freeze-dried bone allograft with specific growth factors

Decalcified freeze-dried bone allograft (DFDBA), believed to serve as a matrix for new bone growth and to contain various bone-inducing growth factors, is currently used to regenerate periodontal defects and to restore and maintain dental alveolar ridges. Growth factors within DFDBA are extracted during the demineralization process, thus rendering the allograft incapable of spontaneous osteogenesis; however, exogenous growth factor addition to DFDBA may enhance the osteogenic capacity of native osteoblasts. This study's purpose is to evaluate murine osteoblast proliferation in the presence of various exogenous soluble growth factors as measured by fluorescence units. Osteoblasts harvested from mouse pup calvaria were cultured with 2% residual calcium-DFDBA and supplemented by one of the following growth factors or combinations of these factors: transforming growth factor-beta (TGF-beta), insulin-like growth factor-I (IGF-I), platelet-derived growth factor (PDGF), fibroblast growth factors basic (bFGF), or vascular endothelial growth factors (VEGF). Osteoblast proliferation rates indicate that the in vitro supplementation of 2% residual calcium-DFDBA with the combination of IGF and TGF-beta, IGF and PDGF, and PDGF and TGF-beta significantly (P < or = .05) enhance murine osteoblast activity and proliferation at 7 days compared with the control containing no exogenous growth factors.     

Antimicrobial effect of triclosan and triclosan with Gantrez on five common endodontic pathogens

Microbial control of the root canal system is one of the key objectives of root canal therapy. Triclosan is a widely accepted broad spectrum antimicrobial agent proven to be effective against many gram-positive and gram-negative bacteria. Triclosan acts by blocking bacterial fatty acid biosynthesis. The addition of Gantrez copolymer has been shown to enhance the antimicrobial activity of triclosan. The purpose of this study was to determine the minimum inhibitory and bactericidal concentrations of triclosan and triclosan with Gantrez against Prevotella intermedia, Fusobacterium nucleatum, Actinomyces naeslundii, Porphyromonas gingivalis, and Enterococcus faecalis. The minimum inhibitory concentration (MIC) of both test solutions was determined for each of the 5 microorganisms by using microtiter serial dilutions. Samples were streaked on 5% sheep blood agar plates and placed in an anaerobic incubator to determine the minimum bactericidal concentration (MBC). The MBC of triclosan ranged from 12-94 microg/mL. The MBC of triclosan with Gantrez ranged from <0.3-10.4 microg/mL. The addition of Gantrez enhanced the bactericidal activity of triclosan. Both triclosan and triclosan with Gantrez demonstrated bactericidal activity against the 5 specific endodontic pathogens.     

Clinical and histological evaluation of immediate-loaded posterior implants in nonhuman primates

PURPOSE: To evaluate a square-thread design implant and compare the bone-implant contact percentage between immediate-loaded and nonloaded implants (controls) in nonhuman primates. MATERIALS: Five nonhuman primates each received 3 implants, with a total of 5 control implants and 10 immediate-loaded implants in posterior regions of the mouth. Ninety days after surgery (and function was appropriate), block sections of the implants were removed and sectioned in 200-mum thick pieces. The block sections were stained with modified Masson for evaluation of the bone-implant contact percentage. RESULTS: One of the immediate-loaded implants failed. The bone-implant contact percentage of control implants ranged from 50.34% to 64.13% and averaged 56.3%. The bone-implant contact percentage of immediate-loaded implants ranged from 43.23% to 75.72%, with an average of 62.4%. Two implants had lower bone-implant contact percentage than the others, and when these are not included in the evaluation, the bone-implant contact percentage average increased to 67.6%. CONCLUSIONS: Immediate-loaded implants in the nonhuman primates often have a higher bone-implant contact percentage at 90 days than unloaded implants. The bone remodeling is different for loaded implant-bone interfaces than for unloaded conditions. However, 1 immediate-loaded implant failed, and 2 implants had lower bone-implant contact percentage than controls. Therefore, although there are benefits of immediate loading, there appear to also be some risks.     

Effects of preservation on the osteoinductive capacity of demineralized bone powder allografts

Demineralized bone powder (DBP) has repeatedly been shown to serve as an osteoinductive material. The aim of this study was to investigate the effects of different methods of storage of DBP on its osteoinductive property. Forty-five Long Evan rats were used in this study. Twenty rats were used as donors; the diaphyses of their femoral bones were used for the preparation of DBP. The DBP was divided into four portions that were either lyophilized or frozen at -70 degrees C, -4 degrees C, or kept at room temperature (25 degrees C). All samples were stored under the specified condition for six months. At the time of implantation, fresh DBP was prepared and used as a control. Twenty-five rats were divided equally into five groups. Each group received an implant of either one of the differently preserved and stored samples of DBP or fresh DBP. The animals were killed 60 days following implantation. The implants were excised and processed to obtain 5 micron thick decalcified sections and 3 micron thick undecalcified sections. Semicomputerized histomorphometry was used for the quantification of the newly-formed bone in each implant. Newly-formed bone was detected in all experimental and control groups and there were no statistically significant differences between the various groups. It was concluded that DBP retains its osteoinductivity after lyophilization or preservation at -70 degrees C, -4 degrees C, and 25 degrees C for a period of up to six months, and that the different methods of preservation did not significantly affect the amount of the induced newly-formed bone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of pluronic polyols as carriers for grafting materials: study in rat calvaria defects

BACKGROUND: Pluronic polyols are a family of non-ionic surfactants currently used as drug carriers for antibiotic, anti-inflammatory, and anti-neoplastic agents. Therapeutic administration of non-ionic surface-active agents is known to facilitate early collagen synthesis and microcirculation, thus promoting wound healing. The purpose of this study was to determine the in vivo effects of pluronic polyols combined with either an allograft or an alloplast on the healing of critical-sized calvarial defects. METHODS: One hundred fifty (150) adult (95 to 105 days old) male Sprague-Dawley rats weighing between 375 and 425 g were randomly and evenly assigned to each of 15 separate treatment groups and anesthetized, and 8 mm calvarial critical-sized defects were created. Pluronic F-68 (F-68) or pluronic F-127 (F-127) was administered either topically or systemically and in conjuction with demineralized bone powder (DBP), tricalcium phosphate (TCP), or non-grafted controls. Pluronic polyols are easily mixed with either DBP or TCP to improve handling ease. Calvaria were harvested at 12 weeks postsurgery and evaluated histomorphometrically, by contact radiography with subsequent densitometric analysis, through energy spectrometry utilizing a scanning electron microscope, and by fluorescent microscopy. RESULTS: There was a significant difference in the percentage of bone fill among the control, TCP, and DBP only groups, P <0.05. The only significant difference within any of these groups was between the TCP control and TCP plus systemic F-127, P<0.05. CONCLUSIONS: Although there were isolated differences, the overall trend was that the pluronic polyol and the mode of administration did not result in a significant change in bone wound healing as measured by the percentage of bone fill. Pluronic polyols may be considered as carriers for osseous graft materials.     

Gingival crevicular fluid prostaglandin E2 level as a predictor of preterm low birth weight: a pilot investigation

Periodontal infections, which serve as a reservoir of inflammatory mediators such as prostaglandin E(2) (PGE(2)), may pose a threat to the fetal-placental unit and cause preterm delivery. This study was conducted to estimate the levels of PGE(2) in gingival crevicular fluid (GCF) and serum to explore the possible use of the GCF-PGE(2) level as a risk predictor of preterm low birth weight (PLBW). Twenty-two pregnant female patients were selected for the study. Samples of GCF and serum were collected from each patient, and sampling was repeated at one month after parturition. The level of PGE(2) in GCF and serum was estimated using a commercially available ELISA kit (NeogenTM). The mean serum PGE(2) level was 4.4 ng/ml and 1.64 ng/ml before and after parturition, respectively, and the difference was statistically significant (P < 0.001). The mean GCF-PGE(2) level was 5.8 ng/ml and 5.5 ng/ml before and after parturition, respectively, but the difference was not significant. There was positive correlation between the serumPGE(2) and GCF-PGE(2) levels, and there was a negative correlation between PGE(2) level and gestational age. The present findings suggest that there is a weak correlation between maternal GCF-PGE(2) level and birth outcome. Further clinical trials with a larger sample size are warranted for further investigation of the association between GCF-PGE(2) level and PLBW.