Dentin dysplasia type I: a challenge for treatment with dental implants

<p>Abstract</p> <p>Background</p> <p>Dentin dysplasia type I is characterized by a defect of dentin development with clinical normal appearance of the permanent teeth but no or only rudimentary root formation. Early loss of all teeth and concomitant underdevelopment of the jaws are challenging for successful treatment with dental implants.</p> <p>Methods</p> <p>A combination of sinus lifting and onlay bone augmentation based on treatment planning using stereolithographic templates was used in a patient with dentin dysplasia type I to rehabilitate the masticatory function.</p> <p>Results</p> <p>(i) a predisposition for an increased and accelerated bone resorption was observed in our patient, (ii) bone augmentation was successful using a mixture of allogenic graft material with autogenous bone preventing fast bone resorption, (iii) surgical planning, based on stereolithographic models and surgical templates, facilitated the accurate placement of dental implants.</p> <p>Conclusion</p> <p>Bony augmentation and elaborate treatment planning is helpful for oral rehabilitation of patients with dentin dysplasia type I.</p

Osseointegration of zirconia implants: an SEM observation of the bone-implant interface

Background The successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics, biocompatibility, and bright tooth-like color, zirconia (zirconium dioxide, ZrO2) has the potential to become a substitute for titanium as dental implant material. The present study aimed at investigating the osseointegration of zirconia implants with modified ablative surface at an ultrastructural level. Methods A total of 24 zirconia implants with modified ablative surfaces and 24 titanium implants all of similar shape and surface structure were inserted into the tibia of 12 Gottinger minipigs. Block biopsies were harvested 1 week, 4 weeks or 12 weeks (four animals each) after surgery. Scanning electron microscopy (SEM) analysis was performed at the bone implant interface. Results Remarkable bone attachment was already seen after 1 week which increased further to intimate bone contact after 4 weeks, observed on both zirconia and titanium implant surfaces. After 12 weeks, osseointegration without interposition of an interfacial layer was detected. At the ultrastructural level, there was no obvious difference between the osseointegration of zirconia implants with modified ablative surfaces and titanium implants with a similar surface topography. Conclusion The results of this study indicate similar osseointegration of zirconia and titanium implants at the ultrastructural level

Prospects of micromass culture technology in tissue engineering

Tissue engineering of bone and cartilage tissue for subsequent implantation is of growing interest in cranio- and maxillofacial surgery. Commonly it is performed by using cells coaxed with scaffolds. Recently, there is a controversy concerning the use of artificial scaffolds compared to the use of a natural matrix. Therefore, new approaches called micromass technology have been invented to overcome these problems by avoiding the need for scaffolds. Technically, cells are dissociated and the dispersed cells are then reaggregated into cellular spheres. The micromass technology approach enables investigators to follow tissue formation from single cell sources to organised spheres in a controlled environment. Thus, the inherent fundamentals of tissue engineering are better revealed. Additionally, as the newly formed tissue is devoid of an artificial material, it resembles more closely the in vivo situation. The purpose of this review is to provide an insight into the fundamentals and the technique of micromass cell culture used to study bone tissue engineering

Induction of osteogenic markers in differentially treated cultures of embryonic stem cells

<p>Abstract</p> <p>Background</p> <p>Facial trauma or tumor surgery in the head and face area often lead to massive destruction of the facial skeleton. Cell-based bone reconstruction therapies promise to offer new therapeutic opportunities for the repair of bone damaged by disease or injury. Currently, embryonic stem cells (ESCs) are discussed to be a potential cell source for bone tissue engineering. The purpose of this study was to investigate various supplements in culture media with respect to the induction of osteogenic differentiation.</p> <p>Methods</p> <p>Murine ESCs were cultured in the presence of LIF (leukemia inhibitory factor), DAG (dexamethasone, ascorbic acid and β-glycerophosphate) or bone morphogenetic protein-2 (BMP-2). Microscopical analyses were performed using von Kossa staining, and expression of osteogenic marker genes was determined by real time PCR.</p> <p>Results</p> <p>ESCs cultured with DAG showed by far the largest deposition of calcium phosphate-containing minerals. Starting at day 9 of culture, a strong increase in collagen I mRNA expression was detected in the DAG-treated cells. In BMP-2-treated ESCs the collagen I mRNA induction was less increased. Expression of osteocalcin, a highly specific marker for osteogentic differentiation, showed a double-peaked curve in DAG-treated cells. ESCs cultured in the presence of DAG showed a strong increase in osteocalcin mRNA at day 9 followed by a second peak starting at day 17.</p> <p>Conclusion</p> <p>Supplementation of ESC cell cultures with DAG is effective in inducing osteogenic differentiation and appears to be more potent than stimulation with BMP-2 alone. Thus, DAG treatment can be recommended for generating ESC populations with osteogenic differentiation that are intended for use in bone tissue engineering.</p

A histomorphometric meta-analysis of sinus elevation with various grafting materials

Several grafting materials have been used in sinus augmentation procedures including autogenous bone, demineralized freeze-dried bone (DFDBA), hydroxyapatite, β-tricalcium phosphate (β-TCP), anorganic deproteinized bovine bone and combination of these and others. Up to now a subject of controversy in maxillofacial surgery and dentistry is, what is the most appropriate graft material for sinus floor augmentation