In vitro effect of fluoride oral hygiene tablets on artificial caries lesion formation and remineralization in human enamel

<p>Abstract</p> <p>Background</p> <p>Aim of this <it>in-vitro</it>-study was to assess the remineralization potential of a tooth cleaning tablet with different fluoride content.</p> <p>Methods</p> <p>Twenty three caries free impacted third molars were examined, enamel surfaces were wax coated leaving two 3 × 4 mm windows for exposure to demineralization/remineralization cycles. The teeth were randomly assigned to 4 groups of 5 control and 6 experimental teeth. Demineralization by standardised HEC-gel, pH 4.7 at 37°C for 72 h, was alternated by rinsing in remineralization solution, pH 7.0 at 37°C for 72 h, total challenge time 432 h. The negative control group N was treated during remineralization cycles with saline; positive control group P was treated with remineralization solution; experimental group D1 was exposed to remineralization solution containing Denttabs^®-tablets with 1450 ppm F; experimental group D2 was exposed to remineralization solution and Denttabs^®-tablets with 4350 ppm F. Each tooth was cut into serial sections and analyzed by polarized light microscopy for assessment of the different zones of white-spot lesions in 3 representative sections. Statistical analysis was based on the <it>Mann-Whitney</it>-Test.</p> <p>Results</p> <p>Both control groups N(-) and P(+) exhibited characteristic white-spot lesions. The remineralization and the demineralization inhibition of the lesions increased considerably from N<P < D1<D2. Denttabs^®-2 administration showed partial/total remineralization including lamination and/or disappearance of the body of the lesion. The different results of all 4 groups were statistically highly significant (p < 0.01) with both tests.</p> <p>Conclusion</p> <p>Based on these results the novel Denttabs^®formulation represents a highly effective oral hygiene product and the remineralization is correlated to the fluoride content.</p

Comparative histomorphometric analysis between α-Tcp cement and β-Tcp/Ha granules in the bone repair of rat calvaria

This study compared the effect of two bioceramics on the process of bone repair: &#945;-tricalcium phosphate (&#945;-TCP) cement and &#946;-tricalcium phosphate hydroxyapatite particles (&#946;-TCP/HA). Calvarial defects were created in 50 rats, divided into two groups (&#945; and &#946;/HA). Software was used at 7, 21, 60, 90 and 120 days to assess bone formation. Mean new bone formation rates were as follows: &#945; group, 1.6% at 7 days, 5.24% at 21 days, 24% at 60 days, 30.21% at 90 days and 50.59% at 120 days; &#946;/HA group, 1.94% at 7 days, 2.53% at 21 days, 12.47% at 60 days, 26.84% at 90 days and 38.82% at 120 days; control group, 0.15% at 7 days, 10.12% at 21 days, 15.10% at 60 days, 18.94% at 90 days, 48.50% at 120 days. Both materials are osteoconductive and biocompatible. Perhaps the larger rate of new bone formation observed in the &#945;-TCP group, it also occurs in the &#946;-TCP/HA group within a longer time period

Growth and differentiation of human bone marrow osteoprogenitors on novel calcium phosphate cements.

Materials that augment bone cell proliferation and osteogenic activity have important therapeutic implications for bone regeneration and for use in skeletal reconstruction and joint replacement. We have studied the growth and interactions of human bone marrow cells on a variety of new cement composites in vitro. These cement materials are composed of calcium-deficient hydroxyapatites, carbonated apatite and amorphous calcium phosphate. Cell proliferation was significantly reduced and cell differentiation increased in the presence of these cements compared with cells cultured on tissue culture plastic. Alkaline phosphatase, one of the markers of the osteoblast phenotype, was dramatically stimulated by 3 of the 4 cements examined between day 4 and day 10, above levels observed following culture of human osteoblasts on plastic alone. Photomicroscopic examination demonstrated growth and close integration of bone marrow cells and 3 of the composites. Longer term marrow cultures (15 day) on the cements confirmed the stimulation of cell differentiation over proliferation. From these studies, enhanced osteoblastic differentiation was observed on a 70% carbonated apatite, which has a composition similar to bone mineral, whereas, cell toxicity was observed on cells grown on amorphous calcium phosphate. This in vitro culture system demonstrates the use of human bone marrow cells for the potential evaluation of new biomaterials and the development of a novel carbonated apatite that may be of potential use in orthopaedic implants

Prospective study of standalone balloon kyphoplasty with calcium phosphate cement augmentation in traumatic fractures

Prospective consecutive series cases study to investigate the clinical and radiological results of standalone balloon kyphoplasty and cement augmentation with calcium phosphate in traumatic fractures. Independent observer evaluation of radiological and computer tomography results, visual analogue scale (VAS), Roland–Morris score and complications with acute traumatic compression fractures type A, treated with a standalone balloon kyphoplasty and cement augmentation with calcium phosphate (Calcibon™); follow-up time at a mean of 30 months (24–37 months). From August 2002 to August 2003, consecutive patients with traumatic compression fractures (Magerl type A) without neurological deficit underwent standalone kyphoplasty with Calcibon. We report here the pre-, post-operative and the follow-up results, applying the VAS (0–10) for pain rating, the Roland–Morris (0–24) disability score, CT-scan examination, detailed radiographic evaluation of vertebral body (VB) deformity and segmental kyphosis measurement. The pre-operative X-ray measurements, VAS and the 7 days Roland–Morris scores are compared with the post-operative and the 30 months follow-up findings. Twenty-eight patients with 33 treated fracture levels were included in this study. The mean initial vertebral deformity (VB kyphosis) was 17°, corrected to a post-operative of 6°. We noted a loss of correction at the follow-up in comparison to the post-operative standing X-ray at 24 h of 3° vertebral deformity and 3° segmental kyphosis. The VAS score demonstrates a decrease over time from a mean of 8.7–3.1 at 7 days and to 0.8 at the last follow-up. The Roland–Morris disability score demonstrates a similar improvement. We noticed no major complications related to the procedure. The mean cement resorption after 1 year was 20.3% (0.3–35.3%) and is related to the individual biological resorption process and is not predictable. All patients with vertebral fractures as sole medical problem were discharged within 48 h. All active patients returned to the same work within 3 months with the same working ability as before the accident. Standalone balloon kyphoplasty is a potential alternative mini-invasive technique to reduce the fractures. However, due to the intrinsic characteristic of calcium phosphate cement (Calcibon) we recommend the application of this biological cement for standalone reduction and stabilisation only in fractures type A1 and A3.1 in young patient. In case of higher destruction levels of the VB, we propose the utilisation of Calcibon associated with posterior instrumentation. Having regard to the pointed out indications, our preliminary results demonstrate a new possibility to treat this kind of fractures, allowing a rapid handling of pain, early discharge and return to normal activities

Minimally traumatic alveolar ridge augmentation with a tunnel injectable thermo-sensitive alginate scaffold

Injectable bone substitutes and techniques have been developed for use in minimally invasive procedures for bone augmentation. Objective : To develop a novel injectable thermo-sensitive alginate hydrogel (TSAH) as a scaffold to induce bone regeneration, using a minimally invasive tunnelling technique. Material and Methods : An injectable TSAH was prepared from a copolymer solution of 8.0 wt% Poly(N-isopropylacrylamide) (PNIPAAm) and 8.0 wt% AAlg-g-PNIPAAm. In vitro properties of the material, such as its microstructure and the sustained release of recombinant human bone morphogenetic protein-2 (rhBMP-2), were investigated. Then, with the subperiosteal tunnelling technique, this material, carrying rhBMP-2, was injected under the labial periosteum of the maxillary anterior alveolar ridge in a rabbit model. New bone formation was evaluated by means of X-ray, micro-computed tomography (micro-CT), fluorescence labelling, histological study, and immunohistochemistry study. Results : The material exhibited good injectability and thermo-irreversible properties. SEM showed an interconnected porous microstructure of the TSAH. The result of ALP activity indicated sustained delivery of BMP-2 from the TSAH from days 3 to 15. In a rabbit model, both TSAH and TSAH/rhBMP-2 induced alveolar ridge augmentation. The percentage of mineralised tissue in the TSAH/rhBMP-2 group (41.6±3.79%) was significantly higher than in the TSAH group (31.3±7.21%; p<0.05). The density of the regenerating tissue was higher in the TSAH/rhBMP-2 group than in the other groups (TSAH group, positive control, blank control; p<0.05). Conclusions : The TSAH provided convenient handling properties for clinical application. To some extent, TSAH could induce ridge augmentation and mineral deposition, which can be enhanced when combined with rhBMP-2 for a minimally invasive tunnelling injection