45 research outputs found
The in vitro viability and growth of fibroblasts cultured in the presence of different bone grafting materials (NanoBone® and Straumann Bone Ceramic®)
Different clinical applications, including dentistry, are making increasing demands
on bone grafting material. In the present study we have analysed the viability,
proliferation and growth characteristics of fibroblasts cultured in vitro together
with two different bone grafting materials, NanoBone® and Straumann Bone
Ceramic®, over a period of 24 and 28 days respectively. Viability was measured
at least every 72 hours by using the alamarBlue assay, a test that measures
quantitatively cell proliferation and viability but does not require cell fixation or
extraction. After one week of culture fibroblast viability was as high as in controls
for both grafting materials and remained high (> 90%) for the duration of
the experiment. Cell growth was evaluated microscopically. Scanning electron
microscopy revealed a dense fibroblast growth at the surface of both bone grafting
materials after three weeks of in vitro culture. Generally, our in vitro analyses
contribute to further insights into cell - scaffold interactions
Bone graft substitutes in periodontal and peri-implant bone regeneration
Regenerative medicine provides different therapy alternatives alongside gold standard
autogenous grafts for the treatment of periodontal or peri-implant osseous
defects. Continuing progress in the field of alloplastic bone substitutes
has yielded promising solutions to the appropriate indications with the membrane
technique either alone or in combination with enamel matrix derivatives.
Their clinical outcomes, however, still require critical discussion
Bacterial colonisation of interior implant threads with and without sealing
Premature loss of dental implants is due, apart from mechanical factors, to germrelated
inflammation. Gaps and hollow spaces within the implant system, for
example the gap between implant and abutment in the two-part implant system,
may provide a bacterial reservoir causing or maintaining inflammation. The
bacterial spectrum involved is similar to that found in periodontitis.
This in vitro study aimed to scrutinise the capability of Porphyromonas gingivalis
(DSM 20709), the bacterium blamed for inducing peri-implantitis, to pass the
implant/abutment gap in titanium implant systems used for orthodontic anchorage
and to remain vital in the interior. Additionally, the in vitro effectiveness of
gutta percha for gap sealing was examined. Twelve titanium implants (Straumann
®, diameter: 3.3 mm, length 5.5 mm) were provided with abutments at
a defined torque (20 Ncm), six of which were sealed with gutta percha before
screwing in the abutment. Subsequently the implants were placed in a nutrient
solution (thioglycolate boullion with haemin-menadione solution) that contained
Porphyromonas gingivalis. Microbiological specimens were sampled from the
implant interiors after 24 and 72 hours and analysed using culture methods.
There was evidence that penetration of the periodontal pathogen Porphyromonas
gingivalis to the implant interior may occur as early as after 24 hours. Microbes
were also detected in the interior of implants sealed with gutta percha.
The abutment/implant interface in vitro provides a microbiological leakage for
the prospective peri-implantitis-inducing bacterium Porphyromonas gingivalis.
Survival of the bacterium is possible in the interior, so that development of
a bacterial reservoir is assumed. This in vitro trial produced no evidence that
sealing with gutta percha is an effective means to prevent secondary bacterial
colonisation in the implant interior
Histological and fluorescence microscopic examination of the bone/implant interface in orthodontic miniscrews (Mondeal®)
The temporary nature of orthodontic implants demands optimisation of size
and design in order to minimise damage and risk to the patient. Slender and
shorter miniscrews offer the advantage over conventional implants of easier and
more ubiquitous positioning with minimised risk of injury to neighbouring anatomical
structures such as tooth roots, nerves or vessels. The question is raised,
however, as to what extent these advantages are gained at the price of diminished
stability or a more unfavourable bone interface. In order to evaluate the
screw/bone interface, 14 orthodontic miniscrews (Mondeal Medical Systems,
diameter: 1.5 mm, length: 9 mm) were inserted into the right and left mandibles
of 7 pigs (Sus scrofa domestica). Bone fluorochromes were administered in
a defined order for polychrome sequencing. The samples gathered after 70 days
were analysed using histological techniques and fluorescence microscopy. The
lower part of the self-tapping thread displayed undisturbed bone apposition.
Fluorescence microscopy revealed remodelling and bone apposition within the
thread grooves
The clinical application of a new synthetic bone grafting material in oral and maxillofacial surgery
A novel bone formation material based on hydroxyapatite-xerogel is presented.
With the use of the innovative sol-gel technology this material is produced in the
low-temperature range by the addition of silicon dioxide; in its structure it mimics
to a great extent the natural bone matrix. This results in high osteoconductivity
and an osteoprotective effect as well as in complete biodegradation corresponding
to bone formation in the course of natural bone remodelling. Two case reports
are presented
The morphological and clinical relevance of mandibular and maxillary bone structures for implantation
Tooth loss, which interrupts the biocybernetic feedback circuit of the masticatory
system, changes the structures of the jaw bone: such changes are termed
"inactivity atrophy". The mandible is subject to vertical atrophy and the maxilla is
primarily subject to horizontal atrophy. The mandible possesses more compact
bone, the maxilla more spongy; the resorption directions also differ (mandible:
towards the oral aspect; maxilla: towards the vestibular). An implant helps to
restore the biocybernetic feedback system. The amount of available bone, bone
structure, and topographic conditions are crucial factors influencing implant
success. Osseointegration is performed at an early stage (which includes bleeding,
granulation tissue, foreign-body recognition, interactions) and at a late stage
(so-called osseous bridging, development of fibrous and lamellar bone)
The use of ceramic drills on a zirconium oxide basis in bone preparation
The favourable mechanical properties and high biocompatibility of the newly
developed mixed ceramics composed of zirconium oxide and aluminium oxide
have continuously extended the scope of their application. Rotating instruments
on a zirconium oxide basis are regarded as superior to metal burs in dentoalveolar
surgery in terms of favourable temperature effects on the surrounding bone
tissue and the economic advantage that they wear slowly, enabling them to be
used repeatedly. In this study ten round burs made of zirconium oxide and
aluminium oxide mixed ceramics were used for typical dental-alveolar preparation
types on an explanted pig jaw. Prior to the first and following the tenth application
a scanning electron microscopic (SEM) analysis of possible wear signs was conducted.
However, this revealed no evidence of wear or resulting loss of sharpness
The application of bone graft substitutes for alveolar ridge preservation after orthodontic extractions and for augmentation of residual cleft defects
The use of bone substitute materials in orthodontics is to be considered prior to
orthodontic space closure after tooth extraction during the treatment of marked
crowding as well as for treatment of residual defects in cleft-lip-and-palate children.
In both cases the common objective is structure preservation or augmentation
of the alveolar ridge. The demands to be made on the synthetic bone
graft substitute comprise not just complication-free and safe use but also the
chance of early tooth movement into the treated defect area with sufficient
stability of the new tooth position
The biodegradation of hydroxyapatite bone graft substitutes in vivo
Hydroxyapatite (HA) ceramics are widely used for bone reconstruction. They are
osteoconductive and serve as structural scaffolds for the deposition of new bone.
Generally, scaffold materials should be degradable as they affect the mechanical
properties of the reconstructed bone negatively. Degradation by osteoclasts
during the bone remodelling process is desirable but often does not take place.
In the current study we analysed by light microscopy the degradation of two
granular HA implants in critically sized defects in the mandibula of Goettingen
mini-pigs five weeks after implantation. Bio-Oss® consists of sintered bovine
bone and NanoBone® is a synthetic HA produced in a sol-gel process in the
presence of SiO2. We found that both biomaterials were degraded by osteoclasts
with ruffled borders and acid phosphatase activity. The osteoclasts created
resorption lacunae and resorptive trails and contained mineral particles. Frequently,
resorption surfaces were in direct contact with bone formative surfaces
on one granule. Granules, especially of NanoBone®, were also covered by osteoclasts
if located in vascularised connective tissue distant from bone tissue.
However, this usually occurred without the creation of resorption lacunae. The
former defect margins consisted of newly formed bone often without remnants
of bone substitutes. Our results show that the degradation of both biomaterials
corresponds to the natural bone degradation processes and suggest the possibility
of complete resorption during bone remodelling
The survival and proliferation of fibroblasts on orthodontic miniscrews with different surface treatment: an in vitro study
It is of fundamental importance for prosthodontic and orthodontic applications
that there is a short osseointegration time of dental implants without inflammation
of the surrounding tissue. In addition to the chemical properties of the
implant material, the surface morphology is an equally critical parameter. The
objective of this work was to study the effect of two simple surface treatments
on the survival and proliferation of fibroblasts.
Three groups of orthodontic miniscrews (Mondeal®) were used. One group was
given an airflow (EMS, Schweiz) treatment, the second was sand-blasted in the
area of the threading and a third group served as a control. After preparation
sterilised screws were cultured in vitro with fibroblasts (L-929). The metabolic
cell activity on the implant surface was determined after 24, 48 and 120 hours
using the alamarBlue assay and a count of DAPI labelled fibroblasts was performed
with a fluorescence microscope.
After 24 hours, but not at 48 hours and 120 hours, the metabolic activity of the
fibroblasts was slightly decreased for the airflow screw group. Generally, no
significant difference was found regarding metabolic activity and proliferation
of fibroblasts within the different groups