Regenerative effect of basic fibroblast growth factor on periodontal healing in two-wall intrabony defects in dogs.

AIM: The aim of the present study was to evaluate the effect of a basic fibroblast growth factor (bFGF) candidate treatment on periodontal healing in two-wall intrabony defects in dogs. MATERIALS AND METHODS: Two-wall intrabony defects (5 x 5 x 5 mm) were created surgically on the distal and mesial sides of bilateral mandibular second and fourth premolars in four Beagle dogs. bFGF, enamel matrix derivative (EMD) and platelet-derived growth factor with beta-tricalcium phosphate (PDGF/beta-TCP) treatments, and sham-surgery (OFD) were rotated among the four defects in each animal, EMD and PDGF/beta-TCP serving as benchmark controls. The animals were euthanized for radiographic and histologic evaluation at 8 weeks. RESULTS: Bone formation was significantly greater in the bFGF group (4.11 +/- 0.77 mm) than in the EMD (3.32 +/- 0.71 mm; p<0.05) and OFD (3.09 +/- 0.52 mm; p<0.01) groups. The EMD (4.59 +/- 1.19 mm) and PDGF/beta-TCP (4.66 +/- 0.7 mm) groups exhibited significantly greater cementum regeneration with periodontal ligament-like tissue than the OFD group (2.96 +/- 0.69 mm; p<0.01). No significant differences were observed between the bFGF and the PDGF/beta-TCP groups in any of the histometric parameters. CONCLUSIONS: The candidate bFGF treatment supported periodontal regeneration comparable with that of established benchmarks: EMD and PDGF/beta-TCP.

Radio-opacity of core materials for all-ceramic restorations.

The aim of this study was to investigate and compare the radio-opacity of core materials for all-ceramic restorations, such as zirconia (NANOZR and Y-TZP) and alumina, against commercially pure titanium (cpTi) and aluminum. X-ray images were taken under general settings using an X-ray film. The X-ray film images were scanned using a digital scanner, and the darkness at the central area of each specimen image was quantitatively analyzed using an image analysis software. Amongst the materials investigated, alumina showed the most transparency against X-rays. Conversely, both types of zirconia showed the highest radio-opacity, whereby that of NANOZR was slightly lower than that of Y-TZP. This was because NANOZR contained 30 vol% of alumina and its density was also slightly lower than that of Y-TZP.

Effect of surface roughness on initial responses of osteoblast-like cells on two types of zirconia.

The aim of this study was to evaluate the effect of surface roughness on the initial attachment of mouse osteoblast-like cells on ceriastabilized zirconia/alumina nanocomposite (NANOZR) and yttria-stabilized zirconia (3Y-TZP) in comparison to those on pure titanium (Ti) and alumina oxide (AO). Specimens with smooth and rough surfaces were prepared by grinding with diamond paper or by sandblasting, respectively. For four substrates examined, the number of attached cells on the rough surface specimens was significantly higher than that on the smooth surface specimens (p < 0.05). Integrin alpha(5) and beta(1) expression had a greater increase in rough surface specimens than in smooth surface specimens. Actin cytoskeleton organization was, however, similar for both smooth and rough surface specimens. NANOZR and 3Y-TZP produced good cell attachment, similar to Ti and AO. The overall results demonstrated that NANOZR and 3Y-TZP with rough surface could provide good initial cell responses, adequate for future implant usage.

Surface properties and biocompatibility of acid-etched titanium.

The purpose of this study was to evaluate the effects of acid-etched titanium on the biological responses of osteoblast-like MC3T3-E1 cells. Four types of treatments (polishing, sandblasting, concentrated H2SO4 etching, and concentrated H2SO4 etching with vacuum firing) were carried out on the surfaces of commercially pure titanium (cpTi) disks. MC3T3-E1 cells were then cultured on the treated cpTi surfaces. Through surface roughness measurement and SEM analysis, it was found that the acid-etched surfaces showed higher roughness values than the sandblasted ones. Scanning electron microscope analysis showed that the cells on the disks treated with acid-etching and acid-etching with vacuum firing spread as well as the sandblasted ones. There were no significant differences in cell proliferation and collagen production on cpTi among the four different surface treatments. Based on the results of this study, it was concluded that etching with concentrated sulfuric acid was a simple and effective way to roughen the surface of titanium without compromising its biocompatibility.

Favorable periodontal healing of 1-wall infrabony defects after application of calcium phosphate cement wall alone or in combination with enamel matrix derivative: a pilot study with canine mandibles.

BACKGROUND: Although various periodontal regenerative therapies are used, their effects on non-contained infrabony defects are unpredictable. Our previous studies showed that injectable, moldable, fast-setting calcium phosphate cement (CPC) promoted histocompatible periodontal healing in 3-wall intrabony defects. The present study evaluated healing patterns after surgical application of CPC walls with and without an enamel matrix derivative (EMD) in 1-wall infrabony defects in dogs. METHODS: One-wall infrabony defects (5 x 5 x 4 mm) were created surgically on the mesial and distal sides of bilateral mandibular fourth premolars in four beagle dogs. After elevating a full-thickness flap, exposed root surfaces were planed thoroughly. The 16 defects were assigned randomly to one of the following experimental conditions: CPC, CPC+EMD, EMD, and open flap debridement (OFD). Ten weeks post-surgery, the animals were sacrificed, and histologic specimens were prepared for histomorphometric evaluation. RESULTS: Defect sites treated with EMD only exhibited varying degrees of new cementum and new bone formation, whereas the OFD group presented only limited new cementum and bone formation. Defect sites where a CPC wall was implanted (CPC and CPC+EMD groups) revealed significantly greater regeneration of new bone and new cementum than in the EMD and OFD groups. No significant differences were observed between the CPC and CPC+EMD groups. CONCLUSIONS: CPC walls with and without EMD promoted regeneration of alveolar bone and cementum in 1-wall infrabony defects. Space and stable wound healing are believed to be crucial for periodontal regeneration in non-contained infrabony defects.

Bioactive apatite coating on titanium using an alternate soaking process.

We developed a novel apatite coating method that consisted of two-step of chemical treatment: a combined pretreatment of concentrated acid etching and alkaline treatment, followed by alternate soaking. In this study, the effects of the number of reaction cycles, solution temperature, and soaking time on apatite deposition on titanium surface using alternate soaking were investigated. Results revealed that the deposited amount of apatite mainly depended on the number of reaction cycles, and was independent of solution temperature and soaking time. Characterization results revealed that apatite formation using alternate soaking basically depended on ion exchange and adsorption on the pretreated surface. Further, apatite coating using alternate soaking on a 200-grid titanium mesh confirmed that this coating method was applicable for substrates with complicated shapes.

Acid etching of titanium for bonding with veneering composite resins.

Commercially pure titanium (cpTi) was etched using three concentrated acids: 18% HCl, 43% H3PO4, and 48% H2SO4. The bond strengths between five types of veneering composite resin and eight cpTi treatments (involving combinations of sandblasting, acid etching in 48% H2SO4, and vacuum firing) were determined before and after 10,000 and 20,000 thermal cycles. There were no significant differences in the bond strength of resin to cpTi after etching in 48% H2SO4 at 90 degrees C for 15 minutes, at 60 degrees C for 15, 30, or 60 minutes, and after sandblasting with and without vacuum firing (p > 0.05); moreover, these treatments yielded the highest values. As for vacuum firing, it had no significant effect on resin bond strength to cpTi before or after 10,000 and 20,000 thermal cycles. We therefore concluded that acid etching in concentrated H2SO4 is a simple and effective surface modification method of titanium for bonding to veneering composite resins.