bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual improvement with corticosteroid therapy in giant cell arteritis. Report of a large study and review of literature
Authors: Hayreh Sohan Singh , Zimmerman Bridget , Kardon Randy H.
Published: March 2003

Objectives:  (1) To report the incidence and extent of visual improvement achieved by high‐dose systemic corticosteroid treatment in eyes with visual loss due to giant‐cell arteritis (GCA). (2) To understand the cause of the discrepancies between visual improvement revealed by routine visual acuity (VA) and by the central visual field in kinetic perimetry. (3) To review critically the contradictory literature on the effectiveness of corticosteroid therapy on visual recovery in GCA and to attempt to reconcile differences in the reported results.

Methods:  Clinical data were collected systematically on 84 consecutive patients (114 eyes) with visual loss, all of whom had GCA confirmed by temporal artery biopsy and treated by us with high‐dose systemic corticosteroid therapy. The patients were treated between 1974 and 1999 and data were compiled retrospectively. All patients underwent a detailed visual and ophthalmic evaluation at the initial visit and at every follow‐up. This included visual field testing (with a Goldmann perimeter). All were treated with systemic corticosteroid therapy (intravenous followed by oral in 41 patients and oral only in 43 patients).

Results:  Visual loss was due to anterior ischaemic optic neuropathy (91%), central retinal artery occlusion (10.5%), cilioretinal artery occlusion (10%), and/or posterior ischaemic optic neuropathy (4%), either alone or in different combinations. Improvement in both VA (≥ 2 lines) and central visual field was found in only five (4%) eyes of five patients (three treated with intravenous and two with oral steroid therapy). Improvement in VA ≥ 2 lines but not in the central visual field was found in seven eyes (in six patients). Visual improvement was seen in 7% of 41 patients treated initially with intravenous steroids versus 5% (p = 0.672) of 43 patients treated with oral steroids only. Comparison of patients with visual improvement in both VA and fields versus those with no improvement suggested a shorter interval (p = 0.065) between onset of visual loss and start of therapy in the improved patients.

Conclusions: In our study, only 4% of eyes with visual loss due to GCA improved, as judged by improvement in both VA and central visual field (by kinetic perimetry and Amsler grid). The data also suggest that there is a better (p = 0.065) chance of visual improvement with early diagnosis and immediate start of steroid therapy. Improvement in VA without associated improvement in the central visual field or Amsler grid may simply represent a learned ability to fixate eccentrically with more effective use of remaining vision: this factor could help explain a number of reported cases in the literature of improved VA after steroid treatment for GCA. To prevent further visual loss in either eye and for management of systemic manifestations of GCA, all patients must be treated on a long‐term basis with adequate amounts of systemic corticosteroids.
Exfoliation syndrome:  Frequency, gender distribution and association with climatically induced alterations of the cornea and conjunctiva
Authors: Forsius Henrik , Forsman Eva , Fellman Johan , Eriksson Aldur W.
Published: March 2003

Purpose: To investigate exfoliation syndrome (ES) in order to elucidate gender distribution and the roles of genetic and climatic factors in its manifestation.

Material and Methods: We studied the gender distribution of ES and the association between ES and the appearance of certain climatically induced disorders (pterygium, climatic droplet keratopathy) and the size of pingueculae in populations living in the Arctic region, in temperate regions and in tropical regions. This involved a total of 11 samples taken in eight different countries, comprising 2206 persons of both genders over the age of 50 years.

Results: A total of 1051 males were investigated for ES and 147 of them (14.0%) were found to have it. The corresponding figures for females were 1093 and 177 (16.2%). After standardization according to age, no systematic difference between the genders was found in the study. The frequency of ES varied greatly. It was not observed at all in the Inuit (Eskimos) but was found most frequently (about 30%) among the Saami (Lapps), Åland Islanders, Finns, Icelanders and Russians over 70 years of age. After the age of 50, the frequency of ES increases rapidly with age in all populations. However, the curves for ES in people living in the tropics show a delay of about 10 years. In contrast, the frequency of climatically caused changes (pterygium, climatic keratopathy and pronounced pinguecula) mostly peaks at the age of 50 years and is highest in the tropics and in the Arctic. Males in these regions tended to be more affected by climatically caused changes than females. Likewise, in tropical climates, where radiation from the sun is strong, and in Lapland and Novosibirsk, where there is radiation from snow, males showed more evidence of ES than females. However, examination of 506 patients from a private practice in South Finland, who were under observation for glaucoma or for risk of glaucoma, showed females to be in the majority of those with ES.

Conclusions: As a rule, climate does not appear to influence the occurrence of ES. However, in tropical countries, where radiation from the sun is strong, ES was more common among males than among females. In the light of its peculiar population distribution, even when climatic factors are considered, there would appear to be an important genetic factor involved in the manifestation of ES.
Changes in visual acuity of patients undergoing cataract surgery during the last two decades
Authors: Leinonen Jaakko , Laatikainen Leila
Published: March 2003

Purpose:  To compare preoperative visual acuities in patients who underwent cataract surgery between 1982 and 2000.

Methods:  Information on visual acuity (VA), ocular disease and general disease was obtained from records relating to samples of consecutive cataract operations in 1982, 1985, 1990, 1995 and 2000 in two hospitals in the Vaasa region of Finland.

Results:  Between 1982 and 2000, the average preoperative VA in the operated eye increased by 0.85 logMAR units (from logMAR 1.56 to logMAR 0.71) or 8.5 log lines. Corresponding decimal values are 0.03 and 0.2, respectively. In the better eye, VA increased from logMAR 0.64 to logMAR 0.37. Corresponding decimal values are 0.23 and 0.43, respectively. The incidence of cataract surgery increased from 1.0 to 7.2 operations per 1000 of the population per year over the period. For an annual increase of one operation per 1000 inhabitants, the increase in average VA before surgery is 1.3 log lines in the operated eye and 0.4 log lines in the better eye. The number of patients with visual impairment (WHO definition: VA < 0.3) before surgery fell from 47% to 15%, and the number of patients with profound visual handicaps (VA < 0.1) before surgery fell from 15% to 4%.

Conclusion:  The preoperative vision of patients undergoing cataract surgery during the last two decades has improved significantly. Preoperative VA has increased linearly in line with the incidence of surgery. Only a small proportion of the increase in incidence of cataract surgery can be explained by the increasing average age of the population.
Evaluation of the clinical association between exfoliation syndrome and abdominal aortic aneurysm
Authors: Hietanen Jaana , Soisalon‐Soininen Sari , Kivelä Tero , Tarkkanen Ahti
Published: March 2003

Purpose:To assess the validity of the suggested association between intraocular exfoliation syndrome and aneurysm of the abdominal aorta.

Methods:A total of 77 patients recently operated for abdominal aortic aneurysm underwent biomicroscopy under pupillary dilatation to detect the presence of manifest and suspect deposits of exfoliation material.

Results:The mean age of the 71 (92%) male and six female subjects was 73 years (range: 59–88 years). Manifest exfoliation was detected in 11 patients (14%; 95% CI 7–24), five of whom were aged 60–69 years and six of whom were aged 70–79 years. In addition, four patients (5%; 95% CI 1–13) had suspect exfoliation.

Conclusions: The prevalence of exfoliation syndrome in patients operated for abdominal aortic aneurysm was similar to that in the general population of the same age in Finland. This finding does not support the proposed connection between exfoliation syndrome and abdominal aortic aneurysm.
Pathological diagnosis of variant Creutzfeldt‐Jakob disease
Authors: Ironside J. W. , McCardle L. , Horsburgh A. , Lim Z. , Head M. W.
Published: March 2003

The neuropathological and biochemical features of the 89 histologically confirmed cases of variant Creutzfeldt‐Jakob disease (vCJD) diagnosed up to the end of October 2001 in the UK are reviewed. Histology of the central nervous system, lymphoid tissues and other organs was accompanied by immunocytochemistry and Western blot analysis of the disease‐associated form of the prion protein (PrPRES). All patients with vCJD were methionine homozygotes at codon 129 of the PrP gene. The pathology of vCJD showed relatively uniform morphological and immunocytochemical characteristics, which were distinct from other forms of CJD. PrPRES accumulation was widespread in lymphoid tissues in vCJD, but was not identified in other non‐neural tissues. PrPRES in vCJD brain tissue showed a uniform glycotype pattern distinct from sporadic CJD. Given the increasingly widespread occurrence of bovine spongiform encephalopathy in Europe and Asia, there is a major need for widespread CJD surveillance. This should be accompanied by a multidisciplinary laboratory approach to the investigation and diagnosis of all forms of CJD, with the need to investigate autopsy tissues from suspected cases by the histological and biochemical techniques described herein.
Comparison of methods of microvascular staining and quantification in prostate carcinoma: Relevance to prognosis
Authors: Offersen Birgitte Vrou , Borre Michael , Sørensen Flemming Brandt , Overgaard Jens
Published: March 2003

High microvascular density in prostate carcinomas may indicate poor prognosis. Our aim was to compare two different anti‐endothelial antibodies and two different ways of evaluating microvascular scores in hot spots (microvessel density (MVD) and Chalkley counts). Adjacent serial sections of formalin‐fixed, paraffin‐embedded tumor specimens from TURPs on 51 consecutive patients with prostate carcinoma were immunostained for CD34 and von Willebrand Factor (vWF). Estimates of microvascular density were based on projecting a 10×10 grid or a Chalkley grid onto a vascular hot spot of the invasive prostate carcinoma. Anti‐CD34 antibodies stained microvessels in all 51 tumors, whereas anti‐vWF antibodies in 6 tumors resulted in intense background staining causing omission of these. Anti‐CD34 antibodies highlighted significantly more microvessels than anti‐vWF antibodies, and the anti‐CD34 vascular scores with either of the counting methods were significantly correlated, which was not the case with vWF. Both grids used on anti‐CD34‐stained sections resulted in vascular scores that could separate the tumors into prognostic groups. This was not possible using the Chalkley grid on vWF‐stained tumors. In conclusion, anti‐CD34 antibodies are sensitive endothelial markers in prostate carcinoma, and the investigated counting methods are compatible. Moreover, high vascular scores seem to carry a poor prognosis.
Follicular hyperplasia presenting with a marginal zone pattern in a reactive lymph node lesion
Authors: Kojima Masaru , Nakamura Shigeo , Motoori Tadashi , Shimizu Kazuhiko , Ohno Yoshihiro , Itoh Hideakki , Masawa Nobuhide
Published: March 2003

Histologically, the marginal zone pattern of the lymph node is characterized by lymphoid follicles with three distinct layers. The inner layer is composed of follicular center zones, the middle layer of darkly stained mantle zones, and the outer layer of marginal zones. However, the marginal zone pattern is rarely seen in reactive lymph nodes except for mesenteric lymph nodes. We describe the clinicopathologic, immunohistochemical and genotypic findings of six cases of reactive follicular hyperplasia exhibiting the marginal zone pattern. The patients comprised three males and three females (age range 24 to 63 years; medium 56 years). Follow‐up data were obtained from five patients. None of them developed malignant lymphomas during the follow‐up period of from 5 to 204 months (median 68 months). Histologically, the lesion was characterized by numerous lymphoid follicles and partial distortion of lymph node structure. Varying degrees of progressive transformation of the germinal center (PTGC) were noted in the four cases. The marginal zone pattern was observed in some or most of the lymphoid follicles including PTGC. The marginal zone B cells were small to medium‐sized lymphocytes with round or slightly indented nuclei and a broad rim of pale cytoplasm. Some of them had a monocytoid appearance. They were CD20+, CD79a+, sIgM+/−, sIgD−, CD5−, CD10−, CD21−, CD23−, CD43−, CD45RO−, Bcl‐6−, cyclin D1−, EMA− and p53−. A portion of them were Bcl‐2 positive. Occasional large lymphoid cells with round or indented nuclei and moderate amounts of cytoplasm were observed in the marginal zone in four cases. These large lymphoid cells were usually CD20 positive, but Bcl‐6 negative. A small number of them contained polytypic intracytoplasmic immunoglobulins. The polytypic nature of B lymphocytes was demonstrated by immunohistochemistry and polymerase chain reaction. Recognition of unusual marginal zone hyperplasia in reactive lymph node lesions is important to avoid confusion with nodal involvement in various low‐grade B cell lymphomas presenting a marginal zone distribution pattern.
In vitro susceptibility ofStaphylococcus aureustowards amoxycillin‐clavulanic acid, penicillin‐clavulanic acid, dicloxacillin and cefuroxime
Authors: Skov ROBERT , Frimodt‐MØLler NIELS , Espersen FRANK
Published: March 2003

Sixty‐threeStaphylococcus aureusisolates with a wide distribution in quantitative β‐lactamase production were tested in vitro against amoxycillin and penicillin in combination with clavulanic acid to establish the influence of total amount of β‐lactamase present on the ability of clavulanic acid to protect against β‐lactamase degradation. The β‐lactamase stability of cefuroxime and dicloxacillin was also evaluated. MIC was determined by agar dilution using Mueller‐Hinton agar with both a conventional as well as a 100 times higher inoculum. The strains were tested both with and without induction of the β‐lactamase production. Clavulanic acid was highly effective in protecting against β‐lactamase degradation of both penicillin and amoxycillin. Even when using a high inoculum of strains with induced β‐lactamase production, all strains had MICs below the NCCLS breakpoint of 4/2 mg/l for amoxycillin‐clavulanic acid. Both cefuroxime and dicloxacillin were highly stable against staphylococcal β‐lactamase degradation. This study encourages further in vivo evaluation of amoxycillin‐clavulanic acid for severe staphylococcal infections.
Periodontal tissues and their counterparts around endosseous implants
Authors: Listgarten M. A. , Lang N. P. , Schroeder H. E. , Schroeder A.
Published: March 2003

New technology coupled with a better understanding of tissue biology has played a key role in restoring the somewhat tarnished image of implant dentistry. Thanks to carefully conducted longitudinal studies, it has now become clear that the replacement of missing teeth by artificial implants integrated into the living tissues of the jaws is a predictable procedure, as long as certain guidelines are followed in the manufacture of the implant, in its placement, in its eventual functional loading, and in its maintenance (Adell et al. 1981, Aibrektsson 1988, Albrektsson et al. 1988, Babbush et al. 1986, Kirsch & Mentag 1986, Smithloff 1986,Smithloff & Fritz 1987). Yet, functional success for a natural tooth is dependent on a number of anatomic, physiologic, and environmental considerations which differ in some important respects from those that insure the functional success of an implant. In this paper, we review theanatomic features of the natural dentition with emphasis on the periodontal tissues, and contrast these characteristics with those that exist 1 around well‐integrated endosseous implants.
The soft tissue barrier at implants and teeth
Authors: Berglundh T. , Lindhe J. , Ericsson I. , Marinello C. P. , Liljenberg B. , Thornsen P.
Published: March 2003

In the present animal experiment. analyses and comparisons were made between the structure and composition of clinically healthy supraalveolar soft tissues adjacent to implants and teeth. 5 beagle dogs were used. The right mandibular premolar region was selected in each dog for placement of titanium implants. while the left mandibular premolar region served as control. Extractions of the mandibular premolars were performed. healing allowed, following which titanium fixtures were installed in the edentolous premolar region. Abutment connection was carried out 3 months later. After another 2 months of healing. plaque control was initiated and maintained for 8 weeks. At the end of the plaque control period. clinical examinations were performed and biopsies harvested from the implant site and the contralateral premolar tooth region. Following fixation and decalcification, all tissue samples were embedded in EPON and examined by histometric and morphometric means. The result from the analyses demonstrated that the peri‐implant mucosa which formed at titanium implants following abutment connection had many features in common with gingival tissue at teeth. Thus, like the gingiva. the peri‐implant mucosa established a cuff‐like barrier which adhered to the surface of the titanium abutment. Further. both the gingiva and the peri‐implant mucosa had a well‐keratinized oral epithelium which was continuous with a junctional epithelium that faced the enamel or the titanium surface. In the periimplant mucosa. the collagen fibers appeared to commence at the marginal bone and were parallel with the abutment surface. All gingival and peri‐implant units examined were free from infiltrates of inflammatory cells. It was suggested that under the conditions of study. both types of soft tissues. gingiva and peri‐implant mucosa. have a proper potential to prevent subgingival I plaque formation.
Treatment of an early implant failure according to the principles of guided tissue regeneration (GTR)
Authors: Lehmann B. , Brägger U. , Hämmerle C. H. F. , Fourmousis I. , Lang N. P.
Published: March 2003

The present case report demonstrates the application of guided tissue regeneration (GTR) in combination with antimicrobial therapy for the treatment of an early implant failure. This treatment approach both prevented further loss of bone as well as led to the regeneration of lost bone. By means of color‐converted digital subtraction images, remodelling of the tissues adjacent to the defect was documented as early as one month postsurgically. The images demonstrated “bone‐fill” in the apical portion of the defect and resorptive changes at the bone crest. This case report demonstrates that combined regenerative and antimicrobial therapy may be a successful treatment approach restoring osseointegration of dental implants following loss of bone due to infection. Continuously increasing bone‐fill inside the defect was documented when comparing the radiograph obtained immediately before the GTR procedure and at months 1, 2, 4, 5 and 6 of the healing period, respectively. Clinical measurement obtained at the time of the surgery and at the time of the membrane removal confirmed the radiographic evidence of bone‐fill by demonstrating new tissue resistant to probing in close contact to the implant surface at the site of the previous defect. Antimicrobial therapy included an antibiotic regimen during the 1st month of healing as well as topical rinses with an antiseptic (chlorhexidine) over the entire healing period of 6 months. As a result of this treatment approach, the implant was saved and could be used as an abutment for a bridge reconstruction.
Endosseous titanium implants during and after orthodontic load ‐ an experimental study in the dog
Authors: Wehrbein H. , Diedrich P.
Published: March 2003

An experiment was carried out to determine whether endosseous titanium implants (Brånemarks®) retain their clinical stability throughout a 26‐week period of continuously applied force (2 N) and what kind of marginal peri‐implant bone changes occur in the process. For this purpose 6 premolars (P3: mandible/maxilla and P4: mandible) were extracted from each of 2 foxhounds, and 12 implants (6 per dog) were positioned in the edentulous maxillary and mandibular areas after the alveolar healing period. Following a 25‐week implant healing period, 8 fixtures (P3 areas) were used as anchoring elements for distalization of the 2nd premolars over a period of 26 weeks: 4 implants served as a control group (P4areas of the mandible). There were no clinical or histological signs of implant dislocation after the load application period. In the presence of mild peri‐implant gingivitis, no increase was found in the incidence of marginal bone resorption adjacent to the loaded implants compared with the non‐loaded implants. In the absence of marginal resorption, subperiosteal bone apposition was detected especially around the test implants in the mandible. This suggests that endosseous titanium implants are suitable as anchoring units for longer‐term orthodontic tooth movements. The applied force may moreover induce marginal bone appositions adjacent I to the implants.
A histomorphometric evaluation of bone‐to‐implant Eontact on machine‐prepared roughened titanium and dental implants. A pilot study in the dog.
Authors: Ericsson I. , Johansson C. B. , Bystedt H. , Norton M. R.
Published: March 2003

This investigation was performed to assess the bone‐to‐implant surface contact at fixtures of titanium that either had a standard machine prepared or a TiO2‐blasted surface. Five beagle dogs were used in the experiment. Extractions of the premolars were performed in the maxilla. After 4 months of healing, 5 standard machine‐prepared fixtures and 5 prepared according to the TioBlast technique were inserted. Two months later another 5 “standard” and 5 TiO Blast‐prepared implants were inserted. Four months after the first fixture installation, the animals were killed and ground sections prepared from each implant site. Of the 20 implants installed, 19 were successfully incorporated. The mean bone‐to‐implant surface for “standard” fixtures was about 40% both at the 2 and 4 months observation interval. The corresponding figures for the TiO Blast‐prepared fixtures were similar during the first 2 months of observation, while subsequently the TioBlast‐prepared fixture surface seemed to stimulate to a more close bone‐to‐implant contact (65%) than the “standard” one.
Retrospective multicenter analysis of 3i endosseous dental implants placed over a five‐year period
Authors: Lazzara R. , Siddiqui A. A. , Binon P. , Feldman S. A. , Weiner R. , Phillips R. , Gonshor A.
Published: March 2003

Osseointegrated dental implants have now become an accepted form of treatment for patients with a fully or partially missing dentition. The purpose of this study was to evaluate the performance of 3i threaded and cylindrical implants. During a 5‐year period, a total of 1969 3i endosseous implants were placed at 6 centers in the United States and 2 elsewhere in the edentulous and partially edentulous jaws of 653 consecutive patients ranging in age from 18 to 82 years. Of the total number of implants placed, 1341 were commercially pure titanium threaded implants and 628 were titanium plasma‐sprayed implants with a cylindrical configuration. A total of 28 patients with 110 implants were lost to follow‐up. Implants in these patients were considered neither a success nor a failure. Success was predicated on the osseointegration of each and every implant followed in this analysis rather than the persistence of prosthetic function. Confirmed bone anchorage was considered essential for success. A total of 625 patients with 1871 implants remain in the study with a follow‐up period ranging from 6 to 60 months. A total of 93 implants (5.0% of the total implants followed) were considered as failures. A mean implant survival rate was 95.0% for both the threaded and the cylindrical implant was calculated. The success rate of threaded implants was 97.0% in the mandible and 93.8% in the maxilla. The success rate for the 3.3mm cylindrical implants was 96.0% in the mandible and 95.5% in the maxilla, and the success rate of 4.0mm diameter cylindrical implants was 95% in the mandible and 92.0% in the maxilla. Causes of failure consisted of loss of osseointegration 2.3%crestal bone loss requiring periodontal therapy after the first year of function 1.7% and mechanical problems associated with the prosthesis 0.9%. This retrospective analysis of the 3i endosseous implant system is comparable to previous reports on other implant systems in terms of implant survival and prosthesis stability. It is demonstrated that 3i implants are predictable and can provide lasting osseointegration leading to improvement of oral function if the recommended surgical and restorative protocol is followed.
Bone regeneration in extraction sites after immediate placement of an e‐PTFE membrane with or without a biomaterial. A report on 12 consecutive cases.
Authors: Diès F. , Etienne D. , Bou Abboud N. , Ouhayoun J. P.
Published: March 2003

The efficacy in restoring a buccal dehiscence after tooth extraction has been studied in12 consecutive cases using guided bone regeneration with (6 patients) or without (6 patients) a biomaterial (DFDBA or Bio Oss®) beneath an e‐PTFE membrane. A correlation between the clinical impression of density at drilling time and the histological signs of bone formation has been evaluated too. The membrane was removed after 6 or 9 months and a biopsy was performed. Clinically, GBR was highly predictable for regeneration of the alveolar bone after tooth extraction with buccal dehiscence. The histology fully confirmed the clinical and radiographical results, showing bone formation in all cases with individual variations in the amount of bone formed. 6‐month biopsies from the membrane sites had lamellar bone with large medullary spaces, while a good bone density was observed at 9 months. The membrane/biomaterial sites demonstrated mineralization and large amounts of allograft at 6 months. Thus, bone regeneration seems to take more time when grafting material is used.
The influence of bone mechanical properties and implant fixation upon bone loading around oral implants
Authors: Van Oosterwyck Hans , Duyck Joke , Vander Sloten Jos , Van der Perre Georges , De Coomans Michel , Lieven Steve , Puers Robert , Naert lgnace
Published: March 2003

Finite element models were created to study the stress and strain distribution around a solitary BAnemark implant. The influence of a number of clinically relevant parameters was examined: bone‐implant interface (fixed bond versus frictionless free contact), bone elastic properties, unicortical versus bicortical implant fixation and the presence of a lamina dura. Bone loading patterns in the vicinity of the implant seem to be very sensitive to these parameters. Hence they should be integrated correctly in numerical models of in vivo behaviour of oral implants. This necessitates the creation of patient‐dependent finite element models.
Characteristics of the cancellous bone of edentulous mandibles
Authors: Ulm C. W. , Kneissel M. , Hahns M. , Solar P. , Matejka M. , Donath K.
Published: March 2003

Trabecular bone volume and trabecular connectivity (trabecular bone pattern factor) of edentulous mandibles were examined using undecalcified bone sections from the region of the 1st premolar to investigate atrophyrelated changes in mandibular cancellous bone. The mean trabecular bone volume was 21.8% in female mandibles and 36.4% in male mandibles. The mean trabecular bone pattern factor was ‐0.22 mm−1 for female mandibles and ‐2.29 mm−1 for male mandibles. The difference between the sexes was statistically conspicuous for both parameters, but did not attain statistical significance. A notable fact was the extreme range of variation in both trabecular bone volume and trabecular connectedness. A difference of 65% between the highest and the lowest trabecular bone volumes measured in the present study (min, 7.6%; max, 73.6%, both male) reflects the possible variation in trabecular density of edentulous mandibles.
Influence of surface treatments developed for oral implants on the physical and biological properties of titanium. (I) Surface characterization.
Authors: Taborelli M. , Jobin M. , François P. , Vaudaux P. , Tonetti M. , Szmukler‐moncler S. , Simpson J. P. , Descouts P.
Published: March 2003

We present an investigation of the physico‐chemical surface properties of commercially pure titanium coverslips which were submitted to various treatments designed to optimize their topography in view of application in oral implantology. The surface microroughness, chemical composition and water wettability were analyzed on titanium coverslips prepared by mechanical polishing, acid attack in HCl/HZSOI, after mechanical polishing or sandblasting, and titanium plasma‐spray. The chemical composition has been measured by Auger electron spectroscopy. The treatments have no major influence on the surface chemical composition and all the samples display a composition approaching that of TiOZ with minor amounts of carbon. sulfur, silicon and calcium as impurities. The roughness has been measured by scanning force microscopy on an area of 20 μm x 20 μm on each sample. Polished titanium is smooth (peak‐to‐valley roughness 81 nm). whereas the acid‐attacked surfaces exhibit a micro‐roughness in the pm range (2100 nm for polished and acid attacked; 3600 nm for sandblasted and acid attacked) which is quite reproducible over large areas of the sample. The acid attacked samples present a subsurface layer which contains hydrogen below the native passivating oxide layer. Water wettability measurement shows that all surfaces are hydrophobic with a slightly higher contact angle for the acid attacked surfaces. The different treatments analyzed in this study essentially influence the surface roughness by preserving the chemical composition and the wettability properties of titanium native oxide surface layer.
Guided bone regeneration around dental implants in the atrophic alveolar ridge using a bioresorbable barrier. An experimental study in the monkey.
Authors: Hürzeler Markus B. , Quiñones Carlos R. , Hutmacher Dietmar , Schüpbach Peter
Published: March 2003

The aim of this study was to evaluate guided bone regeneration (GBR) around dental implants placed in atrophic alveolar ridges using an experimental, nonporous bioresorbable barrier. In 8 Rhesus monkeys, the maxillary canines and lateral incisors were extracted bilaterally and the remaining alveoli were reduced to create atrophic ridges. After a healing period of 3 months, soft tissue expansion was performed using a subperiosteal tissue expander. After 1 month of tissue expansion, an IMZ implant was placed in the atrophic ridge on each side in such a way that its coronal 4 mm to 5 mm remained circumferentially exposed above the bone level. The test implants were covered with a bioresorbable barrier made of poly (D,L‐lactid‐co‐tri‐methylencarbonate) in a 70/30 ratio, whereas the control implants were covered with a nonresorbable expanded polytetrafluoroethylene (e‐PTFE) barrier. The e‐FTFE barriers were stabilized with titanium minipins while the bioresorbable barriers were analogously fixed using bioresorbable minipins made of poly (L‐lactid‐co‐D,L‐lactid) 70/30. Clinical healing progressed uneventfully in both groups and no soft tissue dehiscences occurred. Histometric and histomorphometric analyses were performed 5 months post surgery. Both test and control implants exhibited direct bone‐to‐implant contact to variable extents. The mean direct mineralized bone‐to‐implant contact length fraction was 32% of the total implant length in the test sites and 58% in the control sites. Control sites exhibited significantly greater bone fill compared to the experimental sites (P<0.00l). Histologic observations of test specimens demonstrated a moderate inflammatory reaction related to the degradation and resorption products of the barrier. In conclusion, the nonresorbable eFTFE GBR barrier was found to be superior to the bioresorbable barriers tested in the present investigation.
Some clinical and radiographical features of submerged and non‐submerged titanium implants. A 5‐year follow‐up study.
Authors: Ericsson Lngvar , Randow Kjell , Nilner Krister , Petersson Arne
Published: March 2003

The present study reports on the results of a follow‐up examination of patient material, 5 years after the installation of the fixed supraconstruction. The patient group comprised 11 individuals. Briefly, a split‐mouth technique of treatment was used. In the right side of the mandible the traditional 2‐step surgical approach for implant installation was used. In the left jaw quadrant a l‐step surgical procedure was used. A clinical and radiographical examination was performed 5 years after the initial connection of the supra‐construction to the implants. At the 5 year follow‐up examination all 61 implants examined at the 1 month follow‐up were still in service and found to be clinically stable irrespective of the surgical procedure used. Furthermore, the results of the present clinical and radiographical follow‐up study demonstrate that the marginal bone level at implants placed anteriorly in the edentulous mandible and supporting fixed supraconstructions is stable between 18 and 60 months irrespective of whether placed according to a l‐step or 2‐step surgical procedure.
Comparison of periodontal and peri‐implant probing by depth‐force pattern analysis
Authors: Mombelli Andrea , Muuml;hle Tove , Brägger Urs , Lang Niklaus P. , Bürgin Walter B.
Published: March 2003

The purpose of this study was to compare the tissue resistance to probing and the accuracy of depth determination at different force levels around implants and teeth. In 11 subjects 1 implant and 1 tooth at a comparable location and with comparable probing depth were investigated. The sites were located on either the mesial or distal aspect of the tooth and the implant. A probing device was used which allowed simultaneous monitoring of probing force and probe penetration and which standardized the insertion pathway for repeated measurements. The probing instrument was fitted with an attachment for an aiming device to take a radiograph with the probe tip in the sulcus, using a standardized projection geometry. Probing depth values were determined at 0.25,0.50, 0.75, 1.00 and 1.25 N probing force. The standard error of the individual measurement (S1), evaluated by comparison of repeated measurements in the same session, was 0.2 mm on implants and 0.1 mm on teeth. For implants there was a trend for slightly better reproducibility at higher force levels. Curve analysis of depth force patterns showed that a change in probing force had more impact on the depth reading in the peri‐implant than in the periodontal situation. The mean distance between the probe tip and the periimplant bone crest amounted to 0.75±0.60 mm at 0.25 N probing force. It is concluded that peri‐implant probing depth measurements are more sensitive to force variation than periodontal pocket probing.
Maxillary sinus augmentation using different grafting materials and dental implants in monkeys
Authors: Hürzeler Markus B. , Quiñones Carlos R. , Kirsch Axel , Gloker Christoph , Schüpbachs Peter , Strub Jörg R. , Caffesse Raul G.
Published: March 2003

The aim of this study was to evaluate clinically, histologically and histometrically the use of anorganic bovine bone matrix (i.e. Bio‐oss®) as a grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (i.e. Mucaca mulattu) the 1st 2nd and 3rd maxillary molars on one side of the jaws were extracted. The remaining bone between the alveolar crest and the bottom of the sinus was then reduced to 3–4 mm. After 3 months, maxillary sinus augmentation procedures were performed on one side of the jaws in each monkey and the sinuses were grafted with the bovine bone matrix. At that time, 2 IMZ pure titanium plasma coated implants were immediately placed into the augmented sinuses (i.e. simultaneous implants‐loaded group). After 4 months, 2 additional similar implants were placed into these previously augmented sinuses (i.e. delayed implants‐loaded group). Four months later, the abutment connection was performed and all 4 implants were loaded with a gold‐alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received the same treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants in this side were not loaded. Thus, 2 additional study groups (i.e. simultaneous implants‐unloaded group and delayed implants‐unloaded group) were obtained. Clinically, all loaded implants were stable at the day of sacrifice. Histologically, the grafted sinuses exhibited significant bone formation with integration of the bovine bone matrix particles to the new bone. Direct mineralized bone‐to‐implant contact was greater for the delayed implant placement groups than for the implants installed simultaneously with the sinus augmentation. Furthermore, the percentage of direct mineralized bone‐to‐implant contact was greater in the residual bone than in the augmented area. It was concluded that the anorganic bovine bone matrix facilitated bone formation and implant osseointegration in the augmented sinuses and that the delayed implant placement in combination with the sinus augmentation procedure seemed to be preferable.
Localized ridge augmentation using a micro titanium mesh: a report on 27 implants followed from 1 to 3 vears after functional loading
Authors: Von Arx Thomas , Walkamm Beat , Hardt Nicolas
Published: March 2003

The present paper describes the clinical and radiographic healing results of 27 implants followed from 1 to 3 years after functional implant loading. Prior to implant placement, alveolar ridges with insufficient bone volume were augmented using autogenous bone grafts and a micro titanium mesh for graft stabilization. After a mean interval of 5.2 months implants were installed. Following an osseointegration period of on average 7.2 months, implants were supplied with suprastructures. The mean loading period for the 27 implants was 21 months. All implants exhibited ankylotic stability and healthy peri‐implant soft tissues. The detailed analysis of clinical parameters (probing depth, level of mucosal margin, attachment level, modified plaque and sulcus bleeding indices) and radiographic measurements (crestal bone level), revealed findings similar to those at implants placed into non‐augmented bone. Peri‐implant bone resorption was calculated to be 1.0 mm for the 1st year after implant loading and 0.1 mm for the following year. Pain, suppuration or semilunar bone defects were absent at all implants. It was concluded that loaded dental implants which have been inserted into an augmented alveolar ridge using autogenous bone grafts and a micro titanium mesh for graft stabilization, demonstrate clinical and radiographic findings similar to those of implants placed into a pristine ridge.
Bone healing capacity of titanium plasma‐sprayed and hydroxylapatite‐coated oral implants
Authors: Vercaigne Suzy , Wolke Joop G. C. , Naert Ignace , Jansen John A.
Published: March 2003

The influence of surface quality, in particular surface topography and implant material, was evaluated by inserting titanium‐ and hydroxylapatite plasma‐sprayed coated implants into the maxilla of 10 goats. Three types of plasma‐spray coatings were applied to tapered, screw shaped implants; titanium plasma‐spray coating (TPS), titanium plasma‐spray coating with additional acid passivation (TPSA) and a bilayered coating (TPS/HA) consisting of titanium plasma‐spray coating (TPS) and a hydroxylapatite part (HA). In addition, as machined implants (TIM) were used as control. A total of 40 implants were inserted according a balanced split plot design. At the end of a 3‐month healing period, it appeared that 5 implants (2 TPS, 1 TPSA, 1 TPS/HA and 1 TiM) were lost. Histological examination revealed a stronger bone response to TPS/HA coated implants. Even the TPS/HA coated implants induced bone formation on the part of the implant inserted into the sinus. No signs of delamination of the TPS coatings were visible. The HA part of the dual coating showed signs of degradation. Histomorphometrical analysis confirmed these findings. A significant difference in bone contact (P<0.05) was measured between the TPS/HA coated implants and the other types of implants. Linear regression (r>0.2) showed no correlation between the inscrew values at the base line and the bone contact measurements 3 months after healing. On the basis of these results, we can conclude that the chemical composition of the HA coating has a positive influence on the bone reaction. The influence of roughness is less evident.
Immediate functional loading of Brånemark dental implants. An l8‐month clinical follow‐up study
Authors: Randow Kjell , Ericsson lngvar , Nilner Krister , Petersson Arne , Glantz Per‐olof
Published: March 2003

A clinical and radiographical study was performed to compare the out‐come of oral rehabilitation in the edentulous mandible by fixed supra‐constructions connected to implants installed according to either i) a l‐stage surgical procedure and immediate loading (Experimental Group ‐EG), or ii) the original 2‐stage concept (Reference Group ‐ RG). The EG comprised 16 subjects with edentulous mandibles. Beyond the non‐smoking criteria the following specific inclusion criteria were adopted: i) all patients had to consider themselves to be in good general health, ii( the amount of bone had to enable the installation of 5‐6, at least 10 mm long fixtures to be bicortically anchored (Mk II fixtures; Nobel Biocare AB, Goteborg, Sweden) between the mental foramina, and iii) the patients had to be available for the follow‐up and maintenance programme. A total of 88 implants were placed in the EG (16 patients) compared to 30 in the RG (11 patients). In the EG, fixed appliances were connected to the implants within 20 days following implant installation while the fixed appliances in the RG were connected about 4 months following fixture installation. At the time for delivery of the supraconstructions all 27 patients were radiographically examined, an examination that was repeated at the 18‐month follow‐up. The analysis of the radiographs from the EG disclosed that during the 18‐month observation period the mean loss of bone support amounted to 0.4 mm. The corresponding value observed in the RG was 0.8 mm. During the 18‐month observation period no fixture was lost in any of the 2 groups examined. The implants under study as well as those in the reference material were at all observation intervals found to be clinically stable. The present clinical study demonstrated that it is, at least based on an 18‐month observation period, possible to successfully load titanium dental implants immediately following installation via a permanent fixed rigid cross‐arch supraconstruction. However, such a treatment approach has so far to be strictly limited to the interforamina area of the edentulous mandible.
Temperature increases during surface decontamination of titanium implants using CO2 laser
Authors: Mouhyi Jaafar , Sennerby Lars , Nammour Samir , Guillaume Patrick , Van Reck Jack
Published: March 2003

The purpose of the present in vitro investigation was to measure temperature changes at the implant surface when using pulsed CO2 laser in a simulated implant surface decontamination protocol. Six threaded titanium implants were placed in a fresh resected pig mandible. A 4x4 mm defect was created buccally to each implant in order to expose the implant head and approximately 5 threads. Temperature changes were monitored by two thermocouples placed near the dehiscence and at the apical part of the implant. Several setting combinations of the CO2 laser with regard to output power, pulse width, pulse repetition rate and irradiation time were tested on dry and wet (distilled water) surfaces. Only minor temperature increases were measured when lasing wet titanium surfaces, while the temperature at dry surfaces exceeded the proposed thresholds for bone damage at clinically relevant settings. It is concluded that the CO2 laser when used on a wet implant surface in a pulsed mode at 8 W/l0 ms/ 20 hz during 5 s induces a temperature increase of less than 3oC. This would minimize the risk of temperature induced tissue damage as a result of lasing implant surfaces.
Highly crystalline MP‐1 hydroxylapatite coating Part I: In vitro characterization and comparison to other plasma‐sprayed hydroxylapatite coatings
Authors: Burgess Ann V. , Story Brooks J. , La Danny , Wagner William R. , LeGeros John P.
Published: March 2003

A novel pressurized hydrothermal post‐plasma‐spray process, referred to as MP‐l, has been developed to convert the crystalline non‐HA and amorphous components of plasma‐sprayed hydroxylapatite coatings back into crystalline HA. No detrimental effects are observed on the strength of either the base metal or the coating. X‐ray diffraction (XRD) and FTIR analysis, surface roughness, shear adhesion strength and calcium solubility testing were conducted on Calcitit® coated samples before and after treatment with this process. Other commercially available coatings were also studied using XRD and solubility testing. Quantitative XRD data show that the MP‐1 treatment increases the average crystalline HA content of the Calcitite coating from 17% to 96%, while the amorphous content decreases from 21% to 4%. Other commercially available dental implant coatings ranged in crystalline HA content from 45% to 73%, with amorphous phase content ranging from 29% to 62%. FTIR spectra for treated coatings were significantly more well defined, and showed an increase in peak separation and intensity. Surface roughness and shear adhesion strength were not affected by the treatment. In vitro solubility testing revealed that for all coatings there is an initial introduction of calcium into solution over the first 2 h of testing; however, the amount of calcium dissolved was significantly lower for the MP‐1 coating. Under a pH and temperature representative of normal physiologic conditions, the rate of calcium dissolution for the MP‐1 coating was significantly lower than that of the other commercial HA coatings. In increasingly acidic conditions, the MP‐1 coating was compared to the Calcitite coating and was found to have a significantly slower rate of calcium release. The MP‐1 treatment enhances typical HA coatings by increasing the crystalline HA content at the expense of the plasma‐spray‐induced soluble phases without a reduction in the strength of the coating. The resulting coatings exhibit significantly decreased in vitro solubility over a wide range of pH. The results of this solubility testing suggest that the treated coating may show significantly enhanced in viva stability, even under the extreme conditions encountered during periods of infection or rigorous detoxification procedures. The significant differences between plasma‐sprayed HA coatings reported here underscore the need for industry and academic researchers to raise the level of discourse and understanding of HA coatings. By offering consistent and accurate descriptions of coating compositions and methods of analysis, meaningful comparisons between different HA coatings can be made.