Anatase-based implants nanocoating on stem cells derived from adipose tissue.

PURPOSE: The aim of this study was to investigate the effect of a new anatase coating with antibacterial properties (Bactercline anatase coating [BAC]) on dental implants in the commitment of stem cells derived from adipose tissue to osteoblasts. MATERIALS AND METHODS: Using real-time reverse transcription polymerase chain reaction, the quantitative expression of specific genes, such as transcriptional factors (runx2 and sp7), bone-related genes (spp1, col1a1, col3a1, alpl, and fosl1), and mesenchymal stem cells marker (eng), was examined. RESULTS: BAC caused induction of bone-related genes such as sp7, fosl1, alpl, and spp1. In contrast, the expression of runx2, col3a1, and col1a1 was decreased in stem cells treated with BAC with respect to untreated cells. CONCLUSION: The obtained results are relevant to better understand the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects.

Anorganic bovine bone (Bio-Oss) regulates miRNA of osteoblast-like cells.

Bio-Oss (Geistlich) is composed of an organic bovine bone and has been widely used in several bone regeneration procedures during oral surgery. However, how this biomaterial enhances osteoblast activity to promote bone formation is not completely understood. MicroRNAs (miRNAs) represent a class of small, functional, noncoding RNAs of 19 to 23 nucleotides that regulate the transcription of messenger RNAs (mRNAs) in proteins. In this study, the miRNA microarray technique was used to investigate translation regulation in an osteoblast-like cell line (MG63) exposed to Bio-Oss. Nine up-regulated miRNAs (mir-423, mir-492, mir-191, mir-23a, mir-377, mir-494, mir-214, mir-193b, mir-320) and 4 down-regulated miRNAs (mir-27a, mir-24, mir-188, let-7c) were identified. Because each miRNA regulates 100 mRNAs, only mRNAs related to bone formation were analyzed. The vast majority of detected mRNAs are down-regulated, including some homeobox genes (genes that regulate the morphogenesis of an entire segment of the body), such as noggin and EN1. An indirect positive effect was demonstrated on bone morphogenetic protein-4. To the authors' knowledge, the data reported here are the first on translation regulation in osteoblasts exposed to Bio-Oss. This study may be relevant in better understanding the molecular mechanism of bone regeneration and used as a potential tool for analyzing the combined use of cytokines.

Reconstruction of severely atrophic jaws using homografts and simultaneous implant placement: a retrospective study.

In the past decade, several investigators have reported that implants inserted in autografts in the same operation (ie, simultaneously inserted implants [SIIs]) have achieved excellent results. However, no report regarding SIIs placed in fresh frozen bone (FFB) is available. Thus, the authors planned a retrospective study on a series of SIIs placed in homologue FFB (but not immediately loaded) to evaluate their clinical outcome. In addition, a comparison with implants inserted in FFB in a second stage (ie, delayed inserted implants) was performed. Seventeen patients were grafted with FFB, and 48 implants were inserted in the same operation. Implant diameter and length ranged from 3.25 to 4.0 mm and from 10.0 to 15 mm, respectively. Data were compared with 302 implants inserted in FFB in a second operation during the same period in 64 patients. Analyzing SIIs, it was noted that only 3 implants were lost (ie, survival rate [SVR] = 93.7%), and no differences were detected among the studied variables by using lost implants as a predictor of clinical outcome. On the contrary, by using crestal bone resorption around the implant's neck and specific cutoff values, it was possible to demonstrate that prosthetic restoration (ie, removable overdentures) correlated with a statistically significant lower delta insertion abutment junction (ie, reduced crestal bone loss) and thus with a better clinical outcome. By comparing SIIs with implants inserted in a second stage in FFB, a better outcome for delayed implants was demonstrated. Implants inserted simultaneously with FFB grafts had a high survival and success rate. SIIs inserted in FFB can be considered reliable devices, although a higher marginal bone loss is to be expected when fixed prosthetic restorations are used. Implants inserted in a second surgical stage have a better SVR and success rate than SIIs.

Scoring mandibular fractures: a tool for staging diagnosis, planning treatment, and predicting prognosis.

BACKGROUND: Mandibular fractures (MF) are a daily problem in maxillofacial surgery. A staging system for classifying MF is of paramount importance to plan surgery, to define prognosis, and to exchange information among trauma centers. In this article, a classification for MF is proposed. METHODS: The mandible is divided into six sites (symphysis, body, angle, ramus, coronoid, and condyle) and the mandibular nerve divides the alveolar process (i.e., the upper part containing teeth) from the basal bone (placed caudally with respect to the nerve). MF can be summarized using three abbreviations: A = alveolar, B = basal, and C = complete. Consequently, MFs are staged as follows: F in situ = a greenstick fracture; F1 = a single mobile fragment of alveolar or basal bone; F2 = double mobile fractures of the alveolar or basal portion or a single complete separation of the mandibular arch continuity; F3 = a complete double separation of the mandibular arch continuity; F4 = triple or more mandibular arch fragments. To evaluate the suitability of the proposed classification, a retrospective study on a series of 128 patients (and 205 MFs) was performed. Age, gender, stage, clinical diagnosis at admission, type of surgery, and outcome were considered. RESULTS: A good correlation between the proposed classification and the studied variables was detected. CONCLUSIONS: The new classification is a simple and precise method for staging MF. It can summarize MFs and be used in daily practice. It is our understanding, however, that a multicenter study should be performed before the effectiveness of the proposed classification can be clearly stated.

Evaluation of clinical prognostic factors in T1 N0 M0 head and neck basal cell carcinoma.

This retrospective study was carried out to assess the clinical outcome of stage I (ie, T1 N0 M0) head and neck basal cell carcinoma (HNBCC) and verify the impact of some clinical parameters on prognosis. The cases of 220 patients with stage I (ie, T1 N0 M0) histologically proven HNBCC were analyzed.The global disease-specific survival rate at 36 months was 100%, irrespective of the type of surgery, and thus, it was demonstrated that radical tumor resection is a viable procedure for stage I HNBCC. However, 11 (5%) of 220 cases had a recurrence. A second procedure was performed in 10 (90.9%) of 11 cases. In 3 of the 10 patients operated on twice (30%), a second recurrence was detected. Thus, a second surgical procedure on a recurring tumor is possible, but the multimodality treatment regimen should be considered for recurring tumors.

Iliac crest fresh frozen homografts used in pre-prosthetic surgery: a retrospective study.

In the case of severe jaw atrophy several options are available to restore the alveolar crest. Aim of the present study was to evaluate the resorption over time of homologous fresh frozen bone used to restore the alveolar ridge. Specifically factors influencing (1) graft survival, (2) type, and (3) degree of bone resorption were evaluated. One hundred and thirteen maxillae and 27 mandibles were grafted. The surgical techniques used were 102 inlay, 27 onlay, and 11 veneer. Measurements were taken on pre-operative, post-operative, and follow-up radiographs. Data were processed by using three statistical methods: Kaplan-Meier algorithm, Cox regression, and curve estimation. As regards graft survival, Cox regression output showed a statistically significant effect only on surgical technique (P = 0.0312) and Kaplan-Meier algorithm demonstrated a worse outcome for veneer surgical technique (Log rank test = 0.0242). The Curve estimation demonstrated an inverse correlation between degree of bone resorption over time, with a progressive decrease. In conclusion FFB is a reliable material for alveolar bone restoration with a predicable average of resorption.

Mandibles grafted with fresh-frozen bone: an evaluation of implant outcome.

In the last decade several studies have been performed to evaluate the clinical outcome of implants inserted into grafted mandibles with autologous bone, but none is available on mandibles grafted with fresh-frozen bone. Thus, we planned a retrospective study on a series of implants inserted into homologue fresh-frozen bone to evaluate their clinical outcome. Twenty-one patients were operated on, 28 onlay grafts were inserted into the mandible, and 63 implants placed. Patients had total and partial edentulism in 11 and 10 cases, respectively. The mean follow-up was 20 months. No or reduced crestal bone resorption was considered an indicator of success rate to evaluate the effect of several host-, implant-, and occlusal-related factors. The difference between the implant-abutment junction and the bone crestal level was defined as the implant abutment junction (IAJ) and calculated at the time of operation and during follow-up by means of radiographs. Delta IAJ, the difference between theIAJ at the last check-up and the IAJ recorded just after the operation, were stratified according to variables of interests. Kaplan-Meier algorithm and Cox regression were then performed to detect those variables statistically associated with the delta IAJ. Only 2 of 63 implants were lost (i.e., survival rates = 96.8%) and no differences were detected among the studied variables. On the contrary, Cox regression showed that prosthetic restoration (i.e., removable dentures) was the only factor correlated with a statistically significant lower delta IAJ (i.e., reduced crestal bone loss) and thus a better clinical outcome. Implants inserted into mandibles grafted with fresh-frozen bone allografts have high survival rates and success rate, which are comparable with those obtained with autologous iliac crest bone grafts.

Platform switching and bone platform switching.

Bone platform switching involves an inward bone ring in the coronal part of the implant that is in continuity with the alveolar bone crest. Bone platform switching is obtained by using a dental fixture with a reverse conical neck. A retrospective study was performed to evaluate the effectiveness of conventional vs reverse conical neck implants. In the period between May 2004 and November 2007, 86 patients (55 females and 31 males; median age, 53 years) were operated and 234 implants were inserted: 40 and 194 were conventional vs reverse conical neck implants, respectively. Kaplan-Meier algorithm and Cox regression were used to detect those variables associated with the clinical outcome. No differences in survival and success rates were detected between conventional vs reverse conical neck implants alone or in combination with any of the studied variables. Although bone platform switching leads to several advantages, no statistical difference in alveolar crest resorption is detected in comparison with reverse conical neck implants. We suppose that the proximity of the implant abutment junction to the alveolar crestal bone gives no protection against the microflora contained in the micrograph. Additional studies on larger series and a combination of platform switching and bone platform switching could lead to improved clinical outcomes.

CaPO4 blasted implants inserted into iliac crest homologue frozen grafts.

In the last decade, some investigations have reported that the resorbable blast media surface (also named CaPO4 blasted implants [CaPO4-Bls]) has achieved excellent results. However, no report regarding CaPO4-Bls inserted into fresh frozen bone (FFB) is available. Thus, we planned a retrospective study on a series of CaPO4-Bls inserted into FFB to evaluate their clinical outcome. In the period between December 2003 and December 2006, 16 patients (10 females and 6 males, median age of 55 years) were operated on, and 76 CaPO4-Bls were inserted. The mean implant follow-up was 23 months. Implant diameter and length ranged from 3.25 to 4.5 mm and from 11.5 to 15 mm, respectively. Implants were inserted to replace 7 incisors, 11 cuspids, 31 premolars, and 27 molars. Only 1 out of 76 implants was lost (i.e., survival rate [SVR] = 98.7%), and no differences were detected among the studied variables. When peri-implant crestal bone resorption was used as an indicator of clinical success (i.e., success rate), it was possible to identify some variables that correlated with a better clinical outcome. Specifically, Cox regression showed that removable prosthetic restoration and longer implant length correlated with a statistically significant lower delta implant abutment junction (IAJ; i.e., reduced crestal bone loss) and thus a better clinical outcome. In this study, CaPO4-Bls had high survival and success rates, similar to those reported in previous reports of 2-stage procedures in nongrafted bone. CaPO4-Bls inserted into FFB are reliable devices, although greater marginal bone loss occurs when fixed prosthetic restorations and short implants are used.

Regeneration of Denervated Skeletal Muscles - Brunelli's CNS-PNS Paradigm.

The restoration of voluntary muscle activity in posttraumatic paraplegia in both animal experiments and other clinical applications requires reproducibility of a technically-demanding microsurgical procedure, limited by physicians' understanding of Brunelli's spinal cord grafting paradigm. The insufficient clinical investigation of the long-term benefits of the CNS-PNS graft application warrants additional inquiry. The objective of this study is to explore the potential benefits of the first replicated, graft-induced neuroregeneration of denervated skeletal muscle regarding long-term clinical outcomes and to investigate the effect of Cerebrolysin on neuromodulation. A randomized study evaluating 30 rats, approved by the National Animal Ethics Advisory Committee was performed. The medication was administered postoperatively. For 14 days, 12 rats received Cerebrolysin (serum), 11 received NaCl 0.9% (shams), and 7 were controls. For microsurgery, the lateral corticospinal tract T10 was grafted to the denervated internal obliquus abdominal muscle. On day 90, intraoperative proof of reinnervation was observed. On day 100, 15 rats were euthanized for fixation, organ removal, and extensive histology-morphology examination, and the Wei-Lachin statistical procedure was employed. After an open revision of 16 rats, 8 were CMAP positive. After intravenous Vecuronium application, two (Cerebrolysin, NaCl) out of two rats showed an incomplete compound muscle action potential (CMAP) loss due to glutamatergic and cholinergic co-transmission, while two others showed a complete loss of amplitude. Cerebrolysin medication initiated larger restored muscle fiber diameters and less scarring. FB+ neurons were not observed in the brain but were observed in the Rexed laminae. Brunelli's concept was successfully replicated, demonstrating the first graft induced existence of cholinergic and glutamatergic neurotransmission in denervated grafted muscles. Statistics of the histometric count of muscle fibers revealed larger fiber diameters after Cerebrolysin. Brunelli's CNS-PNS experimental concept is suitable to analyze graft-neuroplasticity focused on the voluntary restoration of denervated skeletal muscles in spinal cord injury. Neuroprotection by Cerebrolysin is demonstrated.

Glutamatergic innervation of rat skeletal muscle by supraspinal neurons: a new paradigm in spinal cord injury repair.

Acetylcholine is the specific chemical code of spinal nerve terminal transmission at the mammalian neuromuscular junction (NMJ), whereas nicotinic acetylcholine receptors inserted into the membrane of muscle fibres mediate signalling for the muscle response. Glutamate has a primary role in neuromuscular transmission of organisms that are phylogenetically distant from mammals, the invertebrates, including insect and molluscs. Recent research has shown that diverting descending glutamatergic fibres in the spinal cord to rat skeletal muscle by means of a peripheral nerve graft causes the cholinergic synapse to switch to the glutamatergic type. These data demonstrate that under appropriate surgical manipulation supraspinal neurons can directly target muscle fibres and specify the postsynaptic receptors to achieve a functional glutamatergic NMJ.

Zirconium oxide coating improves implant osseointegration in vivo.

OBJECTIVES: Zirconium is widely used as material for prosthetic devices because of its good mechanical and chemical properties. When exposed to oxygen, zirconium becomes zirconium oxide (ZO, chemically ZrO(2)) which is biocompatible. ZO can be also prepared as a colloidal suspension and then used to coat surfaces. Zirconium oxide coating (ZOC) can potentially have specific biologic effects. METHODS: The effect of ZOC on bone throughout an in vivo study using dental implants covered with ZOC and then inserted in rabbit tibia was tested in this study. RESULTS: The histologic analysis demonstrated that (1) bone growth is more evident around ZOC fixtures than in controls and (2) a more mature bone is present in the peri-implant ZOC surface than in controls. SIGNIFICANCE: ZOC can enhance implant osseointegration.

Medpor regulates osteoblast's microRNAs.

Porous polyethylene (PP or Medpor) is an alloplastic material worldwide used for craniofacial reconstruction. Although several clinical studies are available, there is a lack as regard the genetic effects. Because PP is always fixed on bone and the mechanism by which PP acts on osteoblasts is unknown, we therefore attempted to address this question by using microRNA microarray techniques to investigate the translation regulation in osteoblasts exposed to PP. The miRNA oligonucleotide microarray provides a novel method to carry out genome-wide microRNA profiling in human samples. By using miRNA microarrays containing 329 probe designed from Human miRNA sequence, we identified in osteoblast-like cells line (MG-63) cultured with Medpor (Porex Corporation, Fairburn, Georgia, USA) several miRNA which expression is significantly modified. We identified 16 up-regulated miRNA (i.e. mir-337, mir-515-3p, mir-377, mir-153, mir-367, mir-152, let-7b, mir-92, mir-155, mir-424, mir-148b, mir-368, mir-18b, mir-520d, mir-20b, mir-128a) and 2 down-regulated miRNA (i.e. mir-143, mir-32). The data reported are, to our knowledge, the first study on translation regulation in osteoblasts exposed to PP. They can be relevant to better understand the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects.

Downregulated gene expression in human palate fibroblasts after cyclosporin A treatment.

BACKGROUND: Cyclosporin A is a powerful immunosuppressive drug with considerable impact on transplants and is able to modify extracellular matrix (ECM) composition. It has recently been demonstrated that cyclosporin A stimulates the production of the cytokine family. Cytokines such as interleukin, transforming growth factor beta(1), and bone morphogenetic protein induce the deposition of glycosaminoglycans (GAGs), proteoglycans, and collagen fibers in the connective ECM. ECM composition is very important for normal tissue development and function. In this work, we examine the effects caused by cyclosporin A on cultures of normal human palate fibroblasts in order to evaluate interleukin, transforming growth factor beta II, and bone morphogenetic protein II membrane receptor induction and extracellular GAG changes such as hyaluronic acid, heparin sulfate, and chondroitin sulfate. METHODS: Palate fibroblasts were maintained for 24 h in serum-free 199 medium containing 5 microg/mL (3)H glucosamine hydrochloride. After this time, TGF II and BMP II receptors were determined by microarray analysis and GAG classes by the biochemical method. RESULTS: The results show that TGFbeta(1) II and BMP II membrane receptors are significantly inhibited in cyclosporin A-treated cultures as compared to controls, whereas IL-1R2 membrane receptors are stimulated. The behavior of total intra- and extracellular GAGs is significantly increased in cyclosporin A-treated cultures, whereas the ratio between non-sulfated/sulfated GAGs decreases (p

Comparison between titanium and anatase miRNAs regulation.

Titanium is the gold standard among materials used for prosthetic devices because of its good mechanical and chemical properties. There are three allotropic forms of titanium dioxide: brookite, rutile, and anatase. Anatase can be prepared as a colloidal suspension and used to coat surfaces. Anatase coating (AC) can potentially have biological effects and specifically can induce bone formation. To obtain more information about the osteogenic effect of AC in comparison to to titanium we used microRNA (miRNA) microarray techniques to investigate the translation regulation in osteoblasts exposed to both titanium and AC. There were three upregulated miRNAs (mir-1, mir-34c, mir-210) and eight downregulated miRNAs (mir-23b, mir-377, mir-22, mir-93, mir-422b, mir-17-5p, mir-24, mir-130b) for false discovery rate = 0 and score >3. The data reported are relevant to understand the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects.

Genetic effects of a titanium surface on osteoblasts: a meta-analysis.

Titanium is used worldwide to make osseointegrable devices. The favorable characteristics that make this material desirable for implantation are i) its mechanical properties and ii) its biocompatibility. The latter has been demonstrated by in vivo studies with animal models and clinical trials over a forty-year period. However, the exact genetic effect of the titanium layer on cells is still not well characterized. To detect the genetic effect of titanium surfacing on osteoblasts without porosity as a confounding variable, a meta-analysis of genetic expression profiling obtained from several titanium surfaces was performed. One hundred seventy-three genes were selected, 84 up-regulated and 95 down-regulated. Among them, the most notable were genes that participate in osteoblast differentiation and bone regeneration, such as TIMP1, PTN, and RUNX1. Titanium surfacing has i) a direct genetic effect on osteoblasts, ii) induces several bone-related genes, and iii) is relevant to the osseointegration process. These properties should be taken into consideration in separating the effect of porosity (i.e. the micro-dimension) from implant coating (i.e. the nano-dimension).

Genetic portrait of osteoblast-like cells cultured on PerioGlas.

PerioGlas (PG) is an alloplastic material used for grafting periodontal osseous defects since 1995. In animal models it has been histologically proven that PG achieves good repair of surgically created defects. In clinical trials, PG has been shown to be effective as an adjunct to conventional surgery in treating intrabony defects. Because the molecular events by which PG is able to alter osteoblast activity to promote bone formation are poorly understood, we investigated genes that are differently regulated in osteoblast-like cells exposed to PG. Bone formation can be attributable to ostegenesis (ie, direct stimulation of osteoblast to produce new bone), osteoconduction (which operates like a scaffold), or both processes. By using DNA microarrays containing 20 000 oligonucleotides, we identified several genes in which expression was significantly downregulated in a MG63 cell line cultured with PerioGlas (US Biomaterials Corp, Alachua, Fla). Specifically, PG is able to downregulate some functional activities of osteoblast-like cells: it acts on signal transduction, especially on the transforming growth factor beta (TGFB) paracrine network; it inhibits apoptosis; it decreases cell adhesion with consequent enhancement of cell mobility and migration; and it acts on bone marrow stem cells (ie, CD34). In conclusion, PG acts on bone formation by determining both osteoconduction (as demonstrated by the reduced cell adhesion) and ostegenesis (as shown by TGFB-related proteins and stem cell markers).

Research on the possibility of overcoming traumatic paraplegia and its first clinical results.

The interruption of the continuity of the spinal cord is still an incurable lesion. In contrast with the peripheral nerves, the axons regenerating from the mother cells of the brain do not progress inside the cord. The reasons of this "non-permissiveness" are still unclear. This article describes the attempts of the author to overcome this non-permissiveness by means of a research that began in 1980 on rats, and continued since 1993 on monkeys. Results of the research on experimental animals were good and convincing so that this operation has been performed on fully informed human being volunteers affected by total severance of the cord between T8 and T11. Results of the first clinical cases are presented regarding operations performed either by rerouting the ulnar nerve to the lower limbs, or connecting the rostral stump of the severed cord with peripheral nerves of the hip to obtain rudimentary, but efficient, walking. Recovery occurred well in advance of the expected time, and continued to improve up to allow the first patient operated on by connecting CNS with PNS to walk with sticks after having walked for some months with a walker. This connection functioned even if the axons activating the single muscles were from mother cells dispersed in different regions of the brain cortex. These cells fire together giving selective contraction of diverse muscles. Furthermore, function occurred although the upper motor neuron uses the neurotransmitter glutamate, whereas motor end plates use receptors for acetylcholine. These data are under further investigation to determine whether the upper motor neuron changes the transmitter, or if the motor end changes its receptors (as seems to be by the first results).

[Surgical repair of spinal cord injuries]. / Les réparations chirurgicales des lésions de la moelle épinière.

Spinal cord rupture is still incurable. Axons regenerating from the brain do not advance through the damaged cord towards peripheral motoneurons. The reasons for this "nonpermissiveness" are unclear. The author's research started in 1980 on rats and monkeys, with attempts to connect the lateral tract of the cord, upstream of the lesion, to the muscles, by means of autologous grafts. This operation was subsequently performed on fully informed volunteers with total cord rupture between T8 and T11. The first patient regained a rudimentary but effective gait. This connection of upper motoneurons with peripheral muscle nerves works even when the activating axons derive from cells dispersed among different regions of the brain cortex but that fire together, providing selective contraction of single muscles. Furthermore, this functioning occurs even though upper motor neurons use the neurotransmitter glutamate, whereas motor endplates normally have acetylcholine receptors. In fact, immunoblot analysis of ChAT VAChT, Vglu-1 GluR1 and GluR2 shows that motor endplate receptors switch from choline to glutamine.

Sensory nerves transfers.

Various types of sensory nerve transfer in the hand are presented. They were all performed after brachial plexus injury to restore sensation, mainly to the adjacent borders of the thumb and index finger or to the ulnar aspect of the little finger. Twenty one cases were assessed. Their outcomes according to the Highet-Zachary system were: S2 in nine cases, S2 in four cases, S1 in four cases and S0 in four cases.