bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating the suitability of nicotinic acetylcholine receptor antibodies for standard immunodetection procedures
Authors: Moser N. , Mechawar N. , Jones I. , Gochberg‐Sarver A. , Orr‐Urtreger A. , Plomann M. , Salas R. , Molles B. , Marubio L. , Roth U. , Maskos U. , Winzer‐Serhan U. , Bourgeois J.‐P. , Le Sourd A.‐M. , De Biasi M. , Schröder H. , Lindstrom J. , Maelicke A. , Changeux J.‐P. , Wevers A.
Published: April 2007

Nicotinic acetylcholine receptors play important roles in numerous cognitive processes as well as in several debilitating central nervous system (CNS) disorders. In order to fully elucidate the diverse roles of nicotinic acetylcholine receptors in CNS function and dysfunction, a detailed knowledge of their cellular and subcellular localizations is essential. To date, methods to precisely localize nicotinic acetylcholine receptors in the CNS have predominantly relied on the use of anti‐receptor subunit antibodies. Although data obtained by immunohistology and immunoblotting are generally in accordance with ligand binding studies, some discrepancies remain, in particular with electrophysiological findings. In this context, nicotinic acetylcholine receptor subunit‐deficient mice should be ideal tools for testing the specificity of subunit‐directed antibodies. Here, we used standard protocols for immunohistochemistry and western blotting to examine the antibodies raised against the α3‐, α4‐, α7‐, β2‐, and β4‐nicotinic acetylcholine receptor subunits on brain tissues of the respective knock‐out mice. Unexpectedly, for each of the antibodies tested, immunoreactivity was the same in wild‐type and knock‐out mice. These data imply that, under commonly used conditions, these antibodies are not suited for immunolocalization. Thus, particular caution should be exerted with regards to the experimental approach used to visualize nicotinic acetylcholine receptors in the brain.
Proteomic analysis of γ‐butyrolactone‐treated mouse thalamus reveals dysregulated proteins upon absence seizure
Authors: Ryu Myung‐Jeom , Kim Daesoo , Kang Un‐Beom , Kim Joon , Shin Hee‐Sup , Lee Cheolju , Yu Myeong‐Hee
Published: April 2007

Absence seizure has been of interest because the symptom is related to sensory processing. However, the mechanism that causes the disease is not understood yet. To better understand the molecular mechanism related to the disease progress at protein level, we performed proteomic studies using the thalamus of mice for which absence seizure was induced by γ‐butyrolactone (GBL). Differential proteome expression between GBL‐treated mice and control mice was examined by fluorescence 2D difference gel electrophoresis (DIGE) at three different time points (5, 10, and 30 min) after GBL‐administration. We identified 16 proteins differentially expressed by >1.4‐fold at any of the three time points. All proteins besides the serine protease inhibitor EIA were down‐regulated in absence seizure‐induced mice. The down‐regulated proteins can be classified into five groups by their biological functions: cytoskeleton rearrangement, neuroprotection, neurotransmitter secretion, calcium binding, and metabolism. The maximum level of change was reached by 10 min after GBL‐treatment, with the expression level returning back to the original at 30 min when mice were awakened from absence seizure thereby demonstrating the proteomic response is reversible. Our results suggest that absence seizures are associated with restricted functional sets of proteins, whose down‐regulation may interfere with general function of neuronal cells.
Fusion of diphtheria toxin and urotensin II produces a neurotoxin selective for cholinergic neurons in the rat mesopontine tegmentum
Authors: Clark S. D. , Alderson H. L. , Winn P. , Latimer M. P. , Nothacker H.‐P. , Civelli O.
Published: April 2007

Urotensin II is a neuropeptide first isolated from fish and later found in mammals: where it has potent cardiovascular, endocrine and behavioral effects. In rat brain the urotensin II receptor (UII‐R) is predominately expressed in the cholinergic neurons of the pedunculopontine (PPTg) and laterodorsal tegmental nuclei. Typically, the function of the PPTg has been examined using excitotoxins, destroying both cholinergic and non‐cholinergic neurons, which confounds interpretation. We took advantage of UII‐R’s unique expression profile, by combining UII with diphtheria toxin, to engineer a toxin specific for cholinergic neurons of the PPTg. In vitro, two different toxin constructs were shown to selectively activate UII‐R (average EC50 ≈ 30 nmol/L; calcium mobility assay) and to be 10 000‐fold more toxic to UII‐R expressing CHO cells, than wildtype cells (average LD50 ≈ 2 nmol/L; cell viability). In vivo, pressure injection into the PPTg of rats, resulted in specific loss of choline transporter and NADPH diaphorase positive neurons known to express the UII‐R. The lesions developed over time, resulting in the loss of over 80% of cholinergic neurons at 21 days, with little damage to surrounding neurons. This is the first highly selective molecular tool for the depletion of mesopontine cholinergic neurons. The toxin will help to functionally dissect the pedunculopontine and laterodorsal tegmental nuclei, and advance the understanding of the functions of these structures.
Leptin induces interleukin‐1β release from rat microglial cells through a caspase 1 independent mechanism
Authors: Pinteaux Emmanuel , Inoue Wataru , Schmidt Lorraine , Molina‐Holgado Francisco , Rothwell Nancy J. , Luheshi Giamal N.
Published: April 2007

Leptin regulates energy balance by suppressing appetite and increasing energy expenditure through actions in the hypothalamus. Recently we demonstrated that the effects of leptin are, at least in part, mediated by the release of interleukin (IL)‐1β in the brain. Microglia constitute the major source of IL‐1β in the brain but it is not known whether these cells express leptin receptors, or respond to leptin to produce IL‐1β. Using RT‐PCR and immunocytochemistry, we demonstrate that primary rat microglial cells express the short (non‐signalling) and long (signalling) isoforms of the leptin receptors (Ob‐R)s. Immunoassays performed on cell medium collected 24 h after leptin treatment (0.01–10 μg/mL) demonstrated a dose‐dependent production and release of IL‐1β and its endogenously occurring receptor antagonist IL‐1RA. In addition leptin‐induced IL‐1β release occurs via a signal transducer and activator of transcription 3 (STAT3)‐dependent mechanism. Western blot analysis demonstrated that leptin induced the synthesis of pro‐IL‐1β in microglial cells and the release of mature 17 kDa isoform into the culture medium. Leptin‐induced IL‐1β release was neither inhibited by the pan‐caspase inhibitor BOC‐D‐FMK, nor by the caspase 1 inhibitor Ac‐YVAD‐CHO indicating that IL‐1 cleavage is independent of caspase activity. These results confirm our earlier observations in vivo and demonstrate that microglia are an important source of IL‐1β in the brain in response to leptin.
Risk Assessment of Riparian Plant Invasions into Protected Areas
Authors: FOXCROFT LLEWELLYN C. , ROUGET MATHIEU , RICHARDSON DAVID M.
Published: April 2007

Abstract:  Protected areas are becoming increasingly isolated. River corridors represent crucial links to the surrounding landscape but are also major conduits for invasion of alien species. We developed a framework to assess the risk that alien plants in watersheds adjacent to a protected area will invade the protected area along rivers. The framework combines species‐ and landscape‐level approaches and has five key components: (1) definition of the geographical area of interest, (2) delineation of the domain into ecologically meaningful zones, (3) identification of the appropriate landscape units, (4) categorization of alien species and mapping of their distribution and abundance, and (5) definition of management options. The framework guides the determination of species distribution and abundance through successive, easily followed steps, providing the means for the assessment of areas of concern. We applied the framework to Kruger National Park (KNP) in South Africa. We recorded 231 invasive alien plant species (of which 79 were major invaders) in the domain. The KNP is facing increasing pressure from alien species in the upper regions of the drainage areas of neighboring watersheds. On the basis of the climatic modeling, we showed that most major riparian invaders have the ability to spread across the KNP should they be transported down the rivers. With this information, KNP managers can identify areas for proactive intervention, monitoring, and resource allocation. Even for a very large protected area such as the KNP, sustainable management of biodiversity will depend heavily on the response of land managers upstream managing alien plants. We suggest that this framework is applicable to plants and other passively dispersed species that invade protected areas situated at the end of a drainage basin.
The psychological and neurophysiological concomitants of mindfulness forms of meditation
Authors: Ivanovski Belinda , Malhi Gin S.
Published: April 2007

Objective:

To provide a comprehensive review and evaluation of the psychological and neurophysiological literature pertaining to mindfulness meditation.

Methods:

A search for papers in English was undertaken using PsycINFO (from 1804 onward), MedLine (from 1966 onward) and the Cochrane Library with the following search terms: Vipassana, Mindfulness, Meditation, Zen, Insight, EEG, ERP, fMRI, neuroimaging and intervention. In addition, retrieved papers and reports known to the authors were also reviewed for additional relevant literature.

Results:

Mindfulness-based therapeutic interventions appear to be effective in the treatment of depression, anxiety, psychosis, borderline personality disorder and suicidal/self-harm behaviour. Mindfulness meditation per se is effective in reducing substance use and recidivism rates in incarcerated populations but has not been specifically investigated in populations with psychiatric disorders. Electroencephalography research suggests increased alpha, theta and beta activity in frontal and posterior regions, some gamma band effects, with theta activity strongly related to level of experience of meditation; however, these findings have not been consistent. The few neuroimaging studies that have been conducted suggest volumetric and functional change in key brain regions.

Conclusions:

Preliminary findings from treatment outcome studies provide support for the application of mindfulness-based interventions in the treatment of affective, anxiety and personality disorders. However, direct evidence for the effectiveness of mindfulness meditation per se in the treatment of psychiatric disorders is needed. Current neurophysiological and imaging research findings have identified neural changes in association with meditation and provide a potentially promising avenue for future research.
Long chain omega-3 polyunsaturated fatty acids in the treatment of psychiatric illnesses in children and adolescents
Authors: Clayton Edward H. , Hanstock Tanya L. , Garg Manohar L. , Hazell Philip L.
Published: April 2007

Objective:

Long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) are in increasing use in the general population to treat health problems. The objective of the current article is to review the evidence for the rationale and benefit of LCn-3PUFA in the treatment of common psychiatric disorders in children and adolescents.

Methods:

A search of Psychlit, PubMed and Cochrane Databases was conducted using the terms child, adolescent, bipolar, depression, psychosis, first-episode psychosis, schizophrenia, attention deficit hyperactivity disorder (ADHD), autism, psychiatric, omega-3, n-3, docosahexaenoic acid and eicosapentaenoic acid. Further studies were identified from the bibliographies of published reviews.

Results:

One small randomized controlled trial with LCn-3PUFA supplementation in depression in children found a small beneficial effect over placebo. Four placebo-controlled trials showed uncertain benefit of LCn-3PUFA for ADHD. Single placebo-controlled trials showed no benefit in autism or bipolar disorder. There is an absence of studies examining benefit for first-episode psychosis or schizophrenia in children and adolescents.

Conclusions:

While children and adolescents are receiving LCn-3PUFA for a range of psychiatric indications, there is only evidence of likely benefit for unipolar depression.
Astra Tech and Brånemark System Implants: A Prospective 5‐Year Comparative Study. Results after One Year
Authors: Astrand Per , Engquist Bo , Dahlgren Simon , Engquist Eva , Feldmann Hartmut , Gröndahl Kerstin
Published: April 2007

Background: Endosseous dental implants are used frequently, and many implant systems are available. The scientific documentation of the implant system presents a great variation, and it is often difficult to compare studies of different systems.

Purpose: The aim of this study was to compare two Swedish implant systems (Astra Tech and Brånemark System± implants), in a prospective randomized study.

Materials and Methods: Sixty‐six patients were equally distributed between the two implant systems; 184 Astra Tech and 187 Brånemark System implants were used. The patients have been followed annually with clinical and radiographic examinations. The results after 1 year are reported.

Results: The abutment procedure was found to be easier and less time‐consuming with Astra Tech than with Brånemark implants. The operation times in minutes (mean ± SEM) were for the respective implant 35 ± 4.0 and 51 ± 4.8 in the maxilla and 32 ± 3.8 and 43 ± 2.4 in the mandible. The differences in both cases were significant: p <.02 and p <.05, respectively. The failure rate for Astra Tech implants was 0.5% and for Brånemark implants 4.3%. The difference was significant (p <.05); however, taking into account that five of the eight implant losses in the Brånemark implant group occurred in one patient, an intraindividual correlation cannot be excluded. Therefore, this result should be interpreted with caution. The marginal bone level changes were examined already from the fixture installation. The major bone loss was found between fixture installation and baseline. This bone loss was several times greater than the bone loss between the baseline and the 1‐year follow‐up. The total bone loss during the observation period did not differ significantly between the systems, but they had different resorption patterns. The bone loss in the upper jaw between baseline and 1‐year follow‐up was 0.22 ± 0.14 and 0.03 ± 0.09 mm for the Astra Tech and Brånemark implants, respectively. In the lower jaw, the loss was ‐0.31 for both systems. The frequency of plaque accumulation and bleeding on probing did not differ between the implant systems.

Conclusions: Abutment connection with Astra Tech implants was simpler than the corresponding surgery with Brånemark System implants and the survival rate of Astra Tech implants was higher than that of Brånemark system implants.
First and Second Branchial Arch Syndrome: Aspects on the Embryogenesis, Elucidations, and Rehabilitation Using the Osseointegration Concept
Authors: Granström Gosta , Jacobsson Catharina
Published: April 2007

Background: The Osseointegration concept has dramatically changed the possibility of rehabilitating patients with craniofacial defects due to branchial arch syndromes.

Purpose: This article describes some problems related to the investigative routines and rehabilitation of individuals with malformations of the first and second branchial arches of the craniofacial region. Animal model systems have increased the knowledge of basic embryonic processes that can explain the extent of the malformations. Though most clinical first and second branchial arch syndromes are likely to be caused by sporadic mutations, inherited syndromes occur and also teratogenically induced syndromes are known. Prenatal diagnosis ruling out heredity and exogenous influence seems possible in the future. The possibility of preventing and alleviating fulminant syndromes prenatally also could be conceivable in the future.

Patients and Methods: The rehabilitation process starts early after birth and should involve a team of specialists including clinical geneticists, pediatricians, audiologists, plastic surgeons, maxillofacial surgeons, otosurgeons, anaplastologists, speech pathologists, pedodontists, and orthodontists. With the development of the Osseointegration concept in which craniofacial prostheses and hearing aids can be adapted on implants anchored in the craniofacial skeleton, a new field in the rehabilitation of these malformations has opened.

Results: Important aspects in the use of the Osseointegration concept include determination of the lowest age for implant surgery, accessibility of adequate bone for implants, the growth of the craniofacial skeleton during childhood, and the possibility for the patient and his or her parents to care for the skin penetration. Adverse tissue reactions, durability of craniofacial prostheses, and the possibility of unknown adverse reactions to metal implants in the body over a long time are other aspects of concern.

Conclusions: Patients with branchial arch syndromes benefit from a well‐planned multidisciplinary rehabilitation process in which osseointegrated bone‐anchored hearing aids and bone‐anchored ear prostheses can be useful tools.
Clinical Experiences of Implant‐Supported Prostheses with Laser‐Welded Titanium Frameworks in the Partially Edentulous Jaw: A 5‐Year Follow‐up Study
Authors: Örtorp Anders , Jemt Torsten
Published: April 2007

Background: Titanium frameworks have been used in the endentulous implant patient for the last 10 years. However, knowledge of titanium frameworks for the partially dentate patient is limited.

Purpose: To report the 5‐year clinical performance of implant‐supported prostheses with laser‐welded titanium frameworks in the partially edentulous jaw.

Materials and Methods: A consecutive group of 383 partially edentulous patients were, on a routine basis, provided with fixed partial prostheses supported by Brånemark implants in the mandible or maxilla. Besides conventional frameworks in cast gold alloy, 58 patients were provided with titanium frameworks with three different veneering techniques, and clinical and radiographic 5‐year data were collected for this group.

Results: The overall cumulative survival rate was 95.6% for titanium‐framework prostheses and 93.6% for implants. Average bone loss during the follow‐up period was 0.4 mm. The most common complications were minor veneering fractures. Loose and fractured implant screw components were fewer than 2%. An observation was that patients on medications for cardiovascular problems may lose more implants than others (p <.05).

Conclusions: The clinical performance of prostheses with implant‐supported laser‐welded titanium frameworks was similar to that reported for conventional cast frames in partially edentulous jaws. Low‐fusing porcelain veneers also showed clinical performance comparable to that reported for conventional porcelain‐fused‐to‐metal techniques.
Anchorage of Titanium Implants with Different Surface Characteristics: An Experimental Study in Rabbits
Authors: Gotfredsen Klaus , Berglundh Tord , Lindhe Jan
Published: April 2007

Purpose:

To compare the anchorage of titanium implants with different surface roughness and topography and to examine histologically the peri‐implant bone after implant removal.

Materials and Methods:

Screw implants with five different surface topographies were examined: (1) turned (“machined”), (2) TiO2‐blasted with particles of grain size 10 to 53 μm; (3) TiO2‐blasted, grain size 63 to 90 μm; (4) TiO2‐blasted, grain size 90 to 125 μm; (5) titanium plasma‐sprayed (TPS). The surface topography was determined by the use of an optical instrument. Twelve rabbits, divided into two groups, had a total of 120 implants inserted in the tibiae. One implant from each of the five surface categories was placed within the left tibia of each rabbit. By a second operation, implants were installed in the right tibia, after 2 weeks in group A and after 3 weeks in group B. Fluorochrome labeling was performed after 1 and 3 weeks. Removal torque (RMT) tests of the implants were performed 4 weeks after the second surgery in group A and 9 weeks after the second surgery in group B. Thus, in group A, two healing groups were created, representing 4 and 6 weeks, respectively. The corresponding healing groups in group B were 9 and 12 weeks. The tibiae were removed, and each implant site was dissected, fixed, and embedded in light‐curing resin. Ground sections were made, and the peri‐implant bone was analyzed using fluorescence and light microscopy.

Results:

The turned implants had the lowest Sa and Sy values, whereas the highest scores were recorded for the TPS implants. The corresponding Sa and Sy values for the TiO2‐blasted implants were higher when a larger size of grain particles had been used for blasting. At all four observation intervals, the TPS implants had the highest and the turned implants the lowest RMT scores. The differences between the various TiO2‐blasted implants were, in general, small, but the screws with the largest Sa value had higher RMT scores at 6, 9, and 12 weeks than implants with lower Sa values.

The histologic analysis of the sections representing 6, 9, and 12 weeks revealed that fractures or ruptures were present in the marginal, cortical peri‐implant bone. In such sections representing the TPS and TiO2‐blasted implant categories, ruptures were frequently found in the zone between the old bone and the newly formed bone, as well as within the newly formed bone.

Conclusions:

The present study demonstrated that a clear relation exists between surface roughness, described in Sa values, and implant anchorage assessed by RMT measurements. The anchorage appeared to increase with the maturation of bone tissue during healing.
Proposed Method for the Standardized Measurement of Marginal Bone Height on Periapical Radiographs with the Brånemark System®
Authors: Galasso Luigi
Published: April 2007

Background:

Strict criteria have been stipulated to evaluate success and failure of dental implants. Periapical radiographs are considered an important means of evaluation. However, there is a lack of standardized and reproducible readily available methods to carry this out.

Purpose:

The purpose of this article is to describe the manufacturing and clinical use of a simple device that enables the clinician to take parallel and reproducible periapical radiographs of dental implants.

Materials and Methods:

Commercially available implant prosthetic components and film holder for periapical radiographs were modified and used clinically.

Results:

Clinically, the device works effectively and does not require significantly more time.

Conclusions:

The described device is a simple appliance with an uncomplicated method to overcome problems with taking parallel and reproducible radiographs of dental implants, which is especially important when measuring marginal bone height.
Implant‐Abutment Interface: Biomechanical Study of Flat Top versus Conical
Authors: Hansson Stig
Published: April 2007

Background: Overloading has been identified as a primary factor behind dental implant failure. The peak bone stresses normally appear in the marginal bone. The anchorage strength is maximized if the implant is given a design that minimizes the peak bone stress caused by a standardized load. Clinical studies have shown that it is possible to obtain a marginal bone level close to the crest of the implant. Different implant systems make use of different designs of the implant‐abutment interface. Different implant‐abutment interfaces imply that the functional load is distributed in different ways upon the implant. According to Saint‐Venant's principle, this will result in different stress patterns in the marginal bone when this reaches levels close to the implant crest.

Purpose: One aim of the study was to theoretically investigate if a conical implant‐abutment interface gives rise to a changed stress pattern in the marginal bone, as compared to a flat top interface, for an axially loaded mandibular titanium implant, the neck of which is provided with retention elements giving effective interlocking with the bone. Further aims were to investigate if the way in which the axial load is distributed on the flat top and on the inner conus respectively affects the stress pattern in the marginal bone. The pertinent stress was considered to be the bone‐implant interfacial shear stress. It was assumed that the marginal bone reached the level of the implant–abutment interface.

Method: The investigation was performed by means of axisymmetric finite element analysis.

Results: The conical implant‐abutment interface of the type studied brought about a decrease in the peak bone‐implant interfacial shear stress as compared to the flat top interface of the type studied. This peak interfacial shear stress was located at the top marginal bone for the flat top implant‐abutment interface whereas it was located more apically in the bone for the conical implant‐abutment interface. The way in which the axial load was distributed on the flat top and on the inner conus respectively affected the peak interfacial shear stress level.

Conclusion: The design of the implant‐abutment interface has a profound effect upon the stress state in the marginal bone when this reaches the level of this interface. The implant with the conical interface can theoretically resist a larger axial load than the implant with the flat top interface.
Measurements Comparing the Initial Stability of Five Designs of Dental Implants: A Human Cadaver Study
Authors: O'Sullivan Dominic , Sennerby Lars , Meredith Neil
Published: April 2007

Background: A number of different dental implant designs are currently in clinical use. A successful outcome of implant placement is thought, at least in part, to be due to the primary stability of an implant after placement. Few data are available for comparing the primary stability characteristics of different implant designs.

Purpose: This investigation compared the primary stability of five types of endosseous dental implant of varying geometry and surface topography.

Materials and Methods: Comparison was made between a standard threaded commercially pure titanium implant (Nobel Biocare AB, Göteborg, Sweden), the Mark II self‐tapping implant (Nobel Biocare AB, Göteborg, Sweden), the Mark IV tapered self‐tapping implant (Nobel Biocare AB, Göteborg, Sweden), the Astra Tioblast (AstraTech AB, Mölndahl, Sweden), and the 3i Osseotite (3I [Implant Innovations Incorporated], Palm Beach, Florida, USA). Fifty‐two fixtures were placed in the maxillary bone of nine unembalmed human cadavers. Implant stability as a function of peak insertion torque and resonance frequency values was recorded for each fixture site after placement. Removal torque was also measured 1‐hour postinsertion. Assessment of bone quality at each site was made.

Results: All of the implants tested demonstrated good primary stability in type 2 and 3 bone. The Standard, Mark II, Osseotite, and Tioblast were less stable when placed into bone type 4. The Mark IV implants appeared to maintain a high primary stability even in Type 4 bone.

Conclusion: When looking across all bone qualities, the Mark IV implant develops a significantly higher insertion torque than the Standard, Mark II, and Osseotite implant types, and a significantly higher resonance frequency value than the Standard implant, indicating a higher interfacial stiffness at the implant–bone interface.
Influence of Prosthesis Material on the Loading of Implants That Support a Fixed Partial Prosthesis: In Vivo Study
Authors: Duyck Joke , Van Oostenvyck Hans , Vander Sloten Jos , De Cooman Michel , Puers Robert , Naert Ignace
Published: April 2007

Background: Since loading is increasingly believed to be a determining factor in the treatment outcome with oral implants, there is a need to expand the knowledge related to the biomechanics of oral implants and its influencing factors.

Purpose: The aim of this study was to investigate the influence of prosthesis material on the distribution and magnitude of load on oral implants carrying a fixed partial prosthesis by in vivo quantification and qualification of this load.

Methods: Eight patients with in total nine three‐unit fixed partial prostheses on three implants and three patients with in total four two‐unit fixed partial prostheses on two implants were selected. Both metal and acrylic resin prostheses were made. Strain gauged abutments were used to measure the load on the supporting implants during controlled load application of 50 N on several positions along the occlusal surface of the prostheses and during maximal biting in maximal occlusion. Additional tests were conducted when the three‐unit prostheses were supported only by two implants, thereby creating an extension pontic.

Results: A significantly better distribution of bending moments with the metal prostheses in comparison to the acrylic resin prostheses was observed in the case of the three‐unit prostheses on two implants. No other difference in load or load distribution with the different prosthesis materials was noted.

Conclusion: The clinical significance of the study reveals an increased risk for bending overload of the implants that are closest to the point of load application only in the case of acrylic resin long span prostheses or acrylic resin prostheses with extensions.
Identification of Bone Morphogenetic Proteins 2 and 4 in Commercial Demineralized Freeze‐dried Bone Allograft Preparations: Pilot Study
Authors: Li Huika , Pujic Zac , Xiao Yin , Artold P. Mark
Published: April 2007

Background: Demineralized freeze‐dried bone allografts (DFDBAs) have been proposed as a useful adjunct in periodontal therapy to induce periodontal regeneration through the induction of new bone formation. The presence of bone morphogenetic proteins (BMPs) within the demineralized matrix has been proposed as a possible mechanism through which DFDBA may exert its biologic effect. However, in recent years, the predicability of results using DFDBA has been variable and has led to its use being questioned. One reason for the variability in tissue response may be attributed to differences in the processing of DFDBA, which may lead to loss of activity of any bioactive substances within the DFDBA matrix. Therefore, the purpose of this investigation was to determine whether there are detectable levels of bone morphogenetic proteins in commercial DFDBA preparations.

Methods: A single preparation of DFDBA was obtained from three commercial sources. Each preparation was studied in triplicate. Proteins within the DFDBA samples were first extracted with 4M guanidinium HCI for seven days at 40 degrees Celsius and the residue was further extracted with 4M guanidinium HCL/EDTA for seven days at 40 degrees celsius. Two anti‐human BMP‐2 and ‐4 antibodies were used for the detection of the presence of BMP's in the extracts.

Results: Neither BMP‐2 nor BMP‐4 was detected in any of the extracts. When recombinant human BMP‐2 and ‐4 were added throughout the extraction process of DFDBA extraction, not only were intact proteins detected but smaller molecular weight fragments were also noted in the extract.

Conclusions: These results indicate that all of the DFDBA samples tested had no detectable amounts of BMP‐2 and ‐4. In addition, an unknown substance present in the DFDBA may be responsible for degradation of whatever BMPs might be present.
Long‐term Follow‐up of Severely Atrophic Edentulous Mandibles Reconstructed with Short Branemark Implants
Authors: Friberg Bertil , Gröndahl Kerstin , Lekholm Ulf , Brånemark Per‐Ingvar
Published: April 2007

Background: Oral implant treatment (Brånemark System) of edentulous mandibles has been presented in numerous studies. However, with regard to the severely atrophic lower jaw, no long‐term follow‐up studies with solely short implants are available.

Purpose: The purpose of the present investigation was to retrospectively follow the long‐term treatment outcome of patients with severely resorbed edentulous mandibles being subjected to oral implant placement with short (6–7 mm) Brånemark implants.

Materials and Methods: A total of 247 standard (7 mm long, 3.75 mm) and 13 wide (6 mm long, 5 mm) implants were inserted in 49 patients, all of whom exhibited severe resorption of edentate mandibles. Fixed implant‐supported prostheses were manufactured for 45 patients, whereas 4 patients received overdentures. The patients were followed for a mean period of 8 years (range, 1–14 yr).

Results: Seventeen implants failed during the study period (cumulative implant survival rate 95.5% at 5‐yr and 92.3% at 10‐yr follow‐up). Implant‐supported constructions were worn continuously throughout the investigation by all study subjects. Marginal bone loss, measured after 1, 5, and 10 years of function, concurred with studies of Brånemark implants placed in more voluminous mandibles. No major clinical or construction complications occurred in the followed patients.

Conclusions: The outcome of the present study showed that placement of short Brånemark implants without the use of bone grafting procedures for reconstruction of severely atrophic edentulous mandibles is a highly predictable treatment procedure.
Biologie Outcome of Single‐Implant Restorations as Tooth Replacements: A Long‐term Follow‐up Study
Authors: Naert Ignace , Koutsikakis George , Duyck Joke , Quirynen Marc , Jacobs Reinhilde , van Steenberghe Daniel
Published: April 2007

Background: The replacement of a single tooth or several teeth by means of single‐implant restorations is an increasingly used method that needs long‐term validation.

Purpose: The goal of this study was to evaluate the outcome of single‐implant restorations by means of fixed restorations and to define the prognosis through marginal bone level estimations.

Materials and Methods: From November 1986 to June 1998, 270 Brånemark implants (215 in the upper jaw) were installed in 219 patients (106 males). Both anterior and posterior sites were involved. Of the 263 single restorations, 28 were placed in private dental offices. The patients were followed until June 1999.

Results: Twelve implants failed before or at abutment connection or within 6 months afterward. Only four implants failed later. The cumulative success rates were 93% for the implants and 96.5% for the restorations over a period of 11 years. The marginal bone loss during the first 6 months after abutment connection reached 0.71 mm and then dropped to 0.036 mm annually over a period of 10 years.

Conclusions: Single‐implant restorations (Brånemark System) are a reliable treatment with a good long‐term prognosis. Failures were concentrated during the healing period and early loading phase.
Interaction of Force‐Fitting and Surface Roughness of Implants
Authors: Skalak Richard , Zhao Yihua
Published: April 2007

Background: Increased surface roughness may increase installation torque and thus appear to increase the initial stability of an implant. However, it is not immediately clear if the increased torque is attributable to an increase in the effective diameter of the implant or to increased resistance of the bone because of the greater roughness.

Purpose: Force‐fitting stresses arise when an implant is placed into a predrilled hole of smaller‐diameter in bone. The purpose of this report is to discuss the interaction of force‐fitting stresses and surface roughness effects and to develop some general guidelines as to clinical procedures based on this theory.

Materials and Methods: Solutions for the force‐fitting stresses are derived from well‐known equations of elasticity. Results: Substantial force‐fitting stresses on the order of several tens of MPa can be generated when a titanium cylinder is placed into a hole in bone, the diameter of which is only 100 m smaller.

Conclusion: When a hole slightly smaller than the implant diameter is prepared for implant placement, force‐fitting stress increases installation torque and stability can be induced. Thus, large surface roughness of implants should not be viewed as an exclusive mechanism for providing a desirable level of initial fixity. Smaller roughness with the same mean diameter is equally effective.
Similarity of Stress Distribution in Bone for Various Implant Surface Roughness Heights of Similar Form
Authors: Skalak Richard , Zhao Yihua
Published: April 2007

Background: Surface roughness effects on osseointegration can be considered from two viewpoints: purely mechanical effects Distresses attributable to roughness and cell and molecular response to surface roughness.

Purpose: The goal of this study is to provide a theoretical basis to understand the effects of surface roughness size on the osseointegration of implants. The emphasis is primarily on the purely mechanical effects.

Methods: Mathematical proofs of some similarity principles are provided.

Results: The main result is that if the geometric form of the roughness or thread cross‐section is held constant, then the peak elastic stress depends on the form but not on the size of the roughness or thread height.

Conclusion: The purely mechanical effects of surface roughness are well understood on a theoretical basis. The interpretation for clinical procedures, however, needs careful attention. Considering the present state of knowledge and clinical experience, no change in the roughness height of current practice is recommended.
Evaluation of Factors Influencing the Marginal Bone Stability around Implants in the Treatment of Partial Edentulism
Authors: Naert Ignace , Duyck Joke , Hosny Mahmoud , Jacobs Reinhilde , Quirynen Marc , van Steenberghe Daniel
Published: April 2007

Background: The original protocol or Branemark to achieve predictable osseointegration for oral implants has substantially been modified. One may question whether results are influenced by those modifications, especially for the longterm prognosis.

Purpose: The goal of the present study was to investigate the impact of those parameters that deviate from the original protocol as defined by P‐I Branemark.

Materials and Methods: In this study, 246 patients with 263 fixed partial prostheses supported by 668 Branemark implants were followed from 1 to 15 years (mean:6.3 yr). Radiographs were taken at the time of abutment connection, at 3 to 6 months, at 12 months, and then every 3 years. The bone level was rated mesially and distally from the implants on a total of 2588 radiographs.

Results: A positive relation between abutment length and marginal bone level was found (p >.0001). The maxilla (p =.03), porcelain (p =.007), long abutments (p =.008), and regular‐sized diameter implants (p =.001) all exhibited more bone loss in the first 6 months. After 6 months, only long implants showed more bone loss (p =.03).

Conclusions: Overall, the marginal bone level remained stable around Branemark implants, never surpassing 2.2 mm, even after 15 years. Although longer implants lost more bone over time, this has to be interpreted with respect to higher resorption rates in less resorbed jaws.
Nonresorbable versus Resorbable Sutures in Oral Implant Surgery: A Prospective Clinical Study
Authors: Ivanoff Carl‐Johan , Widmark Göran
Published: April 2007

Background: Regarding the Brånemark implant system, nonresorbable sutures have been advocated for reapproxima‐tion of the flaps. Fast‐absorbable sutures are frequently used in oral surgery, which is convenient for both the patient and the surgeon. It would be advantageous if fast‐absorbable sutures are suitable in implant surgery as well.

Purpose: The purpose of this study was to compare irradiated polyglactin 910 (Vicryl Rapide, Ethicon GmbH, Norderstedt, Germany) suture with a nonresorbable polyfilament suture (Supramid, Schwarz, Resorba GmbH, Nürnberg, Germany) used in oral implant surgery.

Materials and Methods: The study comprised 101 edentulous patients (52 females, 49 males) who were provided with 350 Brånemark implants. They were randomized to receive either Vicryl Rapide suture (n = 61) or 3‐0 Supramid suture (n = 40). The patients were evaluated after 10 days and at the time of abutment surgery. Any wound complications and implant losses were recorded.

Results: The implant failure rate at abutment surgery was low (1.2%), and no difference was seen between the two suture groups. A higher incidence of complications (mainly wound dehiscence) was found in the absorbable suture group, especially when a continuous suture was used.

Conclusions: The results of this study indicate that it is possible to use irradiated polyglactin 910 sutures in oral implant surgery without affecting the rate of early implant failure. However, it is recommended to add interrupted “security sutures” if a continuous suture technique is used in combination with fast‐absorption suture material.
In Search of Truth: The Role of Systematic Reviews and Meta‐Analyses for Assessing the Effectiveness of Rehabilitation with Oral Implants
Authors: Esposito Marco , Worthington Helen V. , Coulthard Paul
Published: April 2007

Background: It is difficult to determine the effectiveness or potential harm of dental therapies. Thus, any tools able to condense reliable scientific information would be of benefit.

Purpose: To discuss methods for the assessment of the scientific literature and, in particular, of systematic reviews for evaluating the effectiveness of oral implant rehabilitation procedures.

Materials and Methods: Various study designs and methods to identify scientific evidence are described, discussed, and ranked. Issues on how to critically appraise randomized controlled clinical trials (RCTs) and systematic reviews are presented.

Results: Properly conducted RCTs and structured critical systematic reviews are the gold standard of clinical research for assessing whether a therapeutic intervention is effective. In the field of oral implantology, there is an urgent need to implement more RCTs and to summarize their results in systematic reviews.

Conclusions: Searching of the truth requires training and critical skill. Dentists should be trained on how to integrate their clinical experience with evidence‐based research and on how to discriminate between clinically useful scientific information and less useful research.
Preliminary Report of Immediately Loaded Altiva Natural Tooth Replacement Dental Implants
Authors: Buchs Andre U. , Levine Laurence , Moy Peter
Published: April 2007

Background: Osseointegration may be described as a direct contact between living bone and an alloplastic implant. It is thought that a period of undisturbed healing is required to ensure osseointegration. The length of the healing period is dependent on a number of factors, such as implant material, surface configuration, site preparation technique, bone quality, healing capacity of the osteotomy, and implant design. Elimination of the healing period offers distinct advantages in terms of cost of therapy and convenience to patients. Recently, a new one‐piece implant design was proposed that provides improved stability of the implant to allow immediate support of an interim prosthesis.

Purpose: This article presents the initial clinical experiences when the Altiva Natural Tooth Replacement one‐piece implant was used in a human clinical trial.

Materials and Methods: This was a prospective multicenter study of the placement and immediate loading of the one‐piece implant. A total of 142 implants were placed in the jaws of 93 patients. Implants were placed consecutively and were followed at specified intervals in three private clinical practices. Clinical performance was recorded relative to implant survival and prosthesis support.

Results: The implant survival rate was 93.7%, with similar responses in the maxilla (95.0%) and the mandible (92.7%). When implant failure occurred, it was observed as mobility without infection within 3 to 5 weeks of implant insertion.

Conclusions: On the basis of this trial, there is promising evidence that this implant design can succeed at rates similar to other designs that require conventional healing times.
Osseotite Implant: 3‐Year Prospective Multicenter Evaluation
Authors: Davarpanah Mithridade , Martinez Henry , Celletti Renato , Alcoforado Gil , Tecucianu Jean‐François , Etienne Daniel
Published: April 2007

Purpose: This prospective multicenter study evaluates the cumulative success rate of the Osseotite® implant after 3 years of prosthetic loading.

Materials and Methods: A total of 413 Osseotite® implants (Implant Innovations®) were placed in 142 patients (completely or partially edentulous) in five dental offices exclusively devoted to implants. The average age of the patients was 58.3 years. Of the 413 implants, 191 were placed in the maxilla and 222 in the mandible; 271 (65.6%) were posterior implants and 142 (34.4%) were anterior implants. Clinical and radiographic evaluations were made after completion of the prosthetic restoration, after 6 months of loading, at 1 year, and at 3 years.

Results: A cumulative success rate of 95.3% was obtained after 3 years of prosthetic loading. The success rate was similar in both arches: 95.1% in the maxilla and 96.8% in the mandible. Early failures (before prosthetic loading) were greater (n = 12) than late failures (n = 2). After 3 years of prosthetic loading, the marginal bone level of 385 (93.2%) implants were evaluated radiographically. Bone level was at the first thread for 91.4% of the implants. A slightly increased loss was observed around 26 implants (6.7%). Including survival implants, the cumulative implant success rate after 3 years was 96%. A success rate of 98.4% was obtained with 187 short implants (8, 5 and 10 mm) reported in this multicenter evaluation.

Conclusion: This multicenter evaluation demonstrates excellent predictability for Osseotite implants.
The Optimum Tilt Angles and Orientations of PV Claddings for Building-Integrated Photovoltaic (BIPV) Applications
Authors: Yang Hongxing , Lu Lin
Published: April 2007

The tilt and azimuth angles of a photovoltaic (PV) array affect the amount of incident solar radiation exposed on the array. This paper develops a new mathematical model for calculating the optimum tilt angles and azimuth angles for building-integrated photovoltaic (BIPV) applications in Hong Kong on yearly, seasonal, and monthly bases. The influence of PV cladding orientation on the power output of PV modules is also investigated. The correlations between the optimum tilt angle and local weather conditions or local environmental conditions are investigated. The results give reasonable solutions for the optimum tilt angles for BIPV applications for both grid-connected and stand-alone systems.
High-Temperature Liquid-Fluoride-Salt Closed-Brayton-Cycle Solar Power Towers
Authors: Forsberg Charles W. , Peterson Per F. , Zhao Haihua
Published: April 2007

Liquid-fluoride-salt heat transfer fluids are proposed to raise the heat-to-electricity efficiencies of solar power towers to about 50%. The liquid salt would deliver heat from the solar furnace at temperatures between 700°C and 850°C to a closed multireheat Brayton power cycle using nitrogen or helium as the working fluid. During the daytime, hot salt may also be used to heat graphite, which would then be used as a heat storage medium to make night-time operations possible. Graphite is a low-cost high-heat-capacity solid that is chemically compatible with liquid fluoride salts at high temperatures. About half the cost of a solar power tower is associated with the mirrors that focus light on the receiver, and less than one-third is associated with the power cycle and heat storage. Consequently, increasing the efficiency by 20–30% has the potential for major reductions in the cost of electricity. Peak temperatures and efficiencies of current designs of power towers are restricted by (1) the use of liquid nitrate salts that decompose at high temperatures and (2) steam cycles in which corrosion limits peak temperature. The liquid-fluoride-salt technology and closed Brayton power cycles are being developed for high-temperature nuclear reactors. These developments may provide the technology and industrial basis for an advanced solar power tower.