bluuebunny/crossref_metadata_2025 huggingface dataset:
p53 gene mutation and MDM2 overexpression in a case of primary malignant fibrous histiocytoma of the jejunum
Authors: Jiao Yu‐Fei , Nakamura Shin‐Ichi , Sugai Tamotsu , Habano Wataru , Uesugi Noriyuki , Oikawa Moriyasu , Sato Tsukasa
Published: March 2003

Primary malignant fibrous histiocytoma of the gastrointestinal tract is extremely rare. To date, only 10 cases of primary malignant fibrous histiocytoma arising in the small intestine have been reported in the English literature. We describe here the genetic alterations and morphologic features of a primary malignant fibrous histiocytoma arising in the jejunum. Immunohistochemically, the tumor cells expressed vimentin, CD68 and α‐1‐antitrypsin, but were negative for other markers. Ultrastructurally, they showed features of fibroblasts and histiocytes. Immunohistochemical overexpression of p53 and MDM2 was observed. Mutation analysis of the p53 gene detected a missense mutation in codon 158 of exon 5. Our results suggest that p53 gene mutations and MDM2 overexpression may play an important role in the tumorigenesis. To our knowledge, the present report is the first genetic study of this rare lesion.
Epidemiological typing and prevalence of integrons in multiresistant Acinetobacter strains
Authors: Oh Jae Young , Kim Ki Sung , Jeong Yong Wook , Cho Jae We , Park Jong Chun , Lee Je Chul
Published: March 2003

Seventy‐seven Acinetobacter isolates were recovered from patients in a Korean hospital during the period from November to December 1998. The isolates were genotyped using randomly amplified polymorphic DNA (RAPD) analysis for epidemiological relationship, and investigated for antibiotic susceptibility and presence of integrons. Sixty‐nine Acinetobacter baumannii isolates were distributed into five groups by RAPD profiles, with 5, 1, 60, 2 and 1 in each group. The major RAPD group of 60 isolates was further divided into six subgroups by antibiograms. Eight isolates belonging to Acinetobacter DNA group 13TU were distributed among six RAPD groups. Seventy‐three of the Acinetobacter isolates were resistant to eight or more of the antibiotics tested. Integrase genes were detected in 66 of the 69 A. baumannii (96%) and in 5 of the 8 Acinetobacter DNA group 13TU isolates (63%). The intI1 and intI2 genes were found in 63 and 8 isolates, respectively. The intI3 gene was not detected. All integron‐carrying isolates were resistant to multiple antibiotics. All strains isolated from more than one patient carried integrons. According to the results, the presence of integrons was significantly (p<0.01) associated with multiple antibiotic resistance and nosocomial spread in Acinetobacter strains.
Clinical presentation and outcome of bacteraemia caused by beta‐haemolytic streptococci serogroup G
Authors: Hindsholm MARIANNE , SchØNheyder HENRIK C.
Published: March 2003

There has been a considerable increase in annual cases of bacteraemia caused by beta‐haemolytic streptococci serogroup G (GGS) and we therefore undertook a retrospective case review in the Danish County of Northern Jutland. During a 19‐year period (1981–1999) 94 cases were identified in a regional bacteraemia register, and the annual incidence rose from 3.0 per 106 inhabitants in 1981–1987 to 7.4 in 1988–1993 and 17.2 in 1994–1999. Clinical charts were available for 92 cases. The male/female ratio was 52/40 and the median age 71 years, range 15–97 years. Twenty‐seven patients had reduced functional capacity. Fifty‐two cases were community‐acquired. The most common site of infection was the skin followed by the lungs and the urogenital tract. Eleven patients had no apparent site of infection. Underlying disease was present in 81 patients, who shared 149 co‐morbid conditions, and the overall one‐month case fatality rate was 23% (95% confidence limits 15–33%). We conclude that GGS are of increasing importance as a cause of bacteraemic infections and first and foremost affect patients who are aged, debilitated, or suffer from severe or multiple underlying diseases.
Histology of tissues surrounding single crystal sapphire endosseous dental implants. An experimental study in the beagle dog*.
Authors: Fartash B. , Arvidson K. , Ericsson I.
Published: March 2003

9 single crystal sapphire dental implants were installed bilaterally into pre‐extracted areas in the lower jaw of two beagle dogs and histologically analysed after 180 days in situ. 8 implants were stable and radiographs disclosed complete bone healing. Light‐, scanning‐ and transmission electron microscopy demonstrated that the stable implants were surrounded by a mineralizing bone boundary and a mutosa nearly free from inflammatory cell infiltrations. The 9th implant was mobile and surrounded by a non‐mineralized connective tissue capsule containing bundles of collagen. The ultrastructure of the mucosa surrounding the implants closely resembled the mucosa surrounding the tooth. Histometric analysis of the alveolar bone surrounding the stable implants revealed that the value of the bone contact surface ranged from 37.1%% to 86.9% (mean value 61.8%) at the light microscopic level.
Comparison of radiographic image characteristics of Brånemark and IMZ implants
Authors: Sewerin I.P.
Published: March 2003

A Brånemark standard titanium implant and an IMZ plasma flame spray‐coated implant were radiographed experimentally under standardized circumstances. Angulations in relation to film plane and central X‐ray as well as rotations around the implant's longitudinal axis were varied. The influence of implant architecture on image density and image pattern was analyzed and images of the two types of implants were compared. The Brånemark implant is asymmetric and exhibits only radiographic burnout in its apical area. The 4 vertical apical cuts cause very distracting images and leave the impression that the implant is conical. It is possible to evaluate angulations with great accuracy from the thread profile, but there are limited possibilities for estimation of rotational stages. The ZMZ impfnnt shows symmetric images in any projection. The 4 vertical slits cause a disturbing burnout in the central part of the implant in certain views, and radiographic images are very inconstant. Possibilities of estimating angulation and rotation are varying. Differences in radiographic image characteristics are supposed to influence diagnostic yield as they affect the possibilities of identifying osseointegration radiographically and of controlling image identity in I serial radiography.
Bone augmentation at fenestrated implants by an osteopromotive membrane technique. A controlled clinical study.
Authors: Dahlin C. , Andersson L. , Linde A.
Published: March 2003

Lack of bone in localized areas of the jaws frequently poses a problem when placing oral implants. In this clinical study, we have tested an osteopromotive membrane technique for its ability to create bone over buccal fenestrations after fixture installation in the maxilla. 7 patients were selected by the use of CT‐scan. Criteria for patient selection were that the alveolar crest should have a vertical height >I3 mm and a facial‐palatal concavity, where exposure at the central portion of the fixture could be anticipated. One fenestration, randomly chosen, in each patient was covered with an e‐PTFE (expanded polytetrafluoroethylene)(Gore‐Tex GTAM™) membrane. Contralateral fenestrations served as controls (without the placement of a membrane). The amount of newly formed bone was calculated by photometric assessments. The results showed that the fixture fenestrations, treated with the membrane technique, demonstrated a significantly (p <0.005) higher amount of new bone formation compared to the controls, where little or no improvement had taken place at the fenestrations. The study conclusively shows that the membrane technique is a reconstructive technique, able to create new bone at localized bone fenestrations at titanium fixtures. Additionally. the study also demonstrates that the periosteum alone, in adult humans. is not capable of generating new bone at exposed titanium implants.
Radiographic evaluation of crestal bone levels adjacent to nonsubmerged titanium implants
Authors: Weber H. P. , Buser D. , Fiorellini J. P. , Williams R. C.
Published: March 2003

Several parameters have been described to determine success or failure in long‐term evaluations of dental implants. One of these parameters is the observation of changes in peri‐implant bone levels. Studies on submerged implants have analyzed the bone level changes in the pre‐ and post‐loading phases. No such data exist for intentionally nonsubmerged implants. The purposes of this study were: (1) to test the applicability and reproducibillity of a simple computer‐assisted method in the evaluation of changes in peri‐implant bone levels;(2) to establish a baseline for the longterm radiographic follow‐up; and (3) to evaluate changes in crestal bone levels adjacent to nonsubmerged IT1 implants between the 1‐year and 2‐year examination. Standardized periapical radiographs were obtained from 80 implants at the l‐year and 2‐year follow‐up examinations after their placement. The implants were located in different jaw areas of 55 patients and supported single crowns or short‐span fixed partial dentures. For each implant, the distance from implant shoulder to first crestal bone contact (DIB) was measured at the proximal surfaces with a digitizer/computer assembly. Statistically significant greater mean DIB were found at the l‐year (baseline) evaluation for: (I) maxillary sites overall (4.10 x 1.02 mm (SD)) compared with mandibular sites overall (3.61 ± 1.03 mm);(2) maxillary anterior sites (4.08 ± 0.97 mm) compared with mandibular posterior sites (3.60 ± 1.05 mm); and (3) maxillary posterior sites (4.13 ± 1.12 mm) compared with mandibular posterior sites. No statistically significant changes in DIB occurred in any of the jaw locations between the l‐year and 2‐year evaluations. These results indicate similar changes in peri‐implant bone levels for non‐submerged implants over a 2‐year period 1 as reported for submerged fixtures.
A new application of a screw‐plate for prosthetic reconstruction after bilateral total maxillectomy
Authors: Juntunen K. , Kullaa A. , Lamberg M. A. , Virtaniemi J.
Published: March 2003

Satisfactory functional and aesthetic rehabilitation of a patient after total bilateral maxillectomy is a great challenge to the surgeon and prosthodontist. A particular problem is support and retention of the obturator. In the case described, the problem was solved by attaching the prosthesis with finger clasps to a classic AO‐reconstruction plate anchored rigidly with screws to both zygomata. The results in terms of mastication, swallowing, phonation and aesthetics were satisfactory for more than 2 years, when the patient died from brain metastasis and pneumonia. The technique seems promising and merits further study using titanium screws and plates.
Anterior tooth replacement with implants in patients with a narrow alveolar ridge form. A clinical study using guided tissue regeneration.
Authors: Andersson B. , Ödman P. , Widmark G. , Waas A.
Published: March 2003

Clinical and radiographic examination was used to select patients with a suspected need of guided tissue regeneration GTR. Fifteen patients with 20 fixtures were included in the study. Nine (45%) of the fixtures were completely covered with bone at fixture surgery and no GTR was required in these cases. On the remaining 11 fixtures, one or more sites were exposed and thus an expanded polytetrafluoroethylene membrane was used. The regenerative results were assessed using 2 methods, a) calculation of exposed threads in the mouth and on projected colour slides, b) photometric evaluation of exposed area. In total, the membrane group showed a bone gain of 81% when threads were calculated. Almost complete agreement in percentage of bone gain was observed between buccal (80.7%) and lingual (82.6%) sites. Photometric evaluation for the buccal sites showed a bone gain of 74%. Complete bone regeneration (100%) was achieved when healing was free from complications and also under an exposed membrane when infection was absent. The results indicate that the membrane technique is highly successful for treatment of exposed implants when healing is free from complications. It also shows that clinical and radiographic examination is not precise enough to differentiate between those patients planned for routine fixture surgery and those with a supplementary need for GTR. Thus access to GTR technique is important when treatment is 1 planned for borderline cases.
Reliability of spiral tomography with the Scanora® technique for dental implant planning
Authors: Ekestubbe A. , Gröndahl H.‐G.
Published: March 2003

The Scanora X‐ray unit permits linear and rotational narrow beam radiography as well as spiral tomography, making it well suited for implant planning radiography. The purpose of this study was to evaluate the reliability of measurements made in spiral lower jaw tomograms of patients examined with the Scanora® technique. Six observers measured the distance between the alveolar crest and the mandibular canal in spiral tomographic images taken on 40 consecutive patients before implant surgery. In one randomly chosen image from each patient, the observers marked the measuring points at the two locations. The measurements were repeated 2 months later. Three of the observers, all radiologists. excluded in total 11 sets of images considered to improve if retaken. Analysis of variance showed an average standard deviation between observers of 1.67 mm. This was mainly due to the intraobserver variation, 1.07 mm. The variation between plots was significantly larger at the alveolar crest. Confidence intervals showed that reliability improves with multiple readings, either made independently by one observer or separately by several. The inter‐ and intraobserver variation decreased to 1.42 mm and 0.86 mm, respectively. without the images of inferior quality. Compared with a similar study based on hypocycloidal images, the variability was less due to the intraobserver variation and was affected positively by an optimized image quality.
Predictable crestal bone remodelling around two porous‐coated titanium alloy dental implant designs. A radiographic study in dogs.
Authors: Al‐sayyed A. , Deporter D. A. , Pilliar R. M. , Watson P. A. , Pharoah M. , Berhane K. , Carter S.
Published: March 2003

We have previously suggested that altering the height of the porous‐coat segment of a partially porous‐coated TiAl6V4 endosseous dental implant would affect the degree of crestal bone loss occurring during implant function by changing the patterns of stress transfer. This conclusion arose from the analysis of data from several different experiments and lacked a direct intra‐animal comparison. In the present study we have compared two implant designs varying only in the extent to which they were porous‐coated. With one design (type A) the coronal 1.8 mm of the implant root had a machined surface while the remainder of its length was porous‐coated with TiAl6V4 beads. The other design (type B) had all but the coronal‐most 0.75 mm porous‐coated. Two implants of each type were placed in each of 4 dogs and the sites allowed to heal for 4 weeks before re‐entry and prosthesis attachment. Monthly the implant‐supported bridges were removed and radiographs exposed of each implant using a special film holder connected separately to each implant. These radiographs were analyzed for crestal bone loss using both direct visual and computer‐assisted techniques. The results showed that bone remodelled to the machined surface‐to‐porous coat junction for type B implants and achieved a steady state by 12 weeks of function, whereas a longer time was required to achieve this state with type A implants. Significantly more bone loss occurred with the type A design, and this difference was detectable as early as after the first month of function.
X‐ray microanalytical and morphological observations of the interface region between ceramic implant and bone
Authors: Zetterqvist L. , Anneroth G. , Nordenram Å. , Wroblewski R.
Published: March 2003

In 8 monkeys both the maxillary lateral incisors were extracted. In the 16 extraction sites an Al2O3‐ceramic dental implant (Frialit®) was immediately inserted. Eight implants were submerged under the oral mucosa and the other 8 were allowed to penetrate through the mucosa during the observation period. None of the implants was loaded during the observation periods. After experimental periods of 1, 2, 4 and 8 months, the interface region between the implant and bone was examined using scanning‐electron microscopy, X‐ray microanalysis, back scatter, microradiography and light microscopy. The results showed that osseointegration of Al2O3‐ceramic dental implant was obtained. The newly formed bone around the implant filled exactly the contours of the implant. Newly formed bone had a mineral content and a phosphorus‐to‐calcium ratio similar to that of the adjacent older mature jaw bone. There were no differences in the osseointegration rate between the submerged and the nonsubmerged implants. No leakage of aluminium from the implant could be detected in the bone.
Reconstruction of the resorbed edentulous maxilla using autogenous rib grafts and osseointegrated implants
Authors: Köndell P. Å. , Nordenram Å. , Moberg L. E. , Eliasson S. , Nyberg B.
Published: March 2003

14 patients with severely resorbed edentulous maxillae underwent reconstruction by the use of autogenous rib graft on‐lays and osseointegrated Brånemark System® implants in a one‐stage procedure. 75 implants were installed. 16 (21.3%) failed to osseointegrate at the abutment connection. After a mean observation period of 5.2 years, 55 (73.3%) of the original implants were osseointegrated. 10 supplementary implants were inserted in 3 patients. At the end of the observation periods, 2 patients had overdentures and 12 had fixed prostheses. The mean marginal bone loss was 2.13mm (SD 0.47mm) the 1st year after grafting, and 2.92mm (SD 1.27mm) at the end of the follow‐up periods. Long‐term follow‐up did not show any persistent donor site discomfort. The results indicate that this technique is a conceivable alternative for patients with severe maxillary resorption.
The use of palatal implants for orthodontic anchorage. Design and clinical application of the orthosystem.
Authors: Wehrbein H. , Merz B. R. , Diedrich P. , Glatzmaier J.
Published: March 2003

This paper presents the Orthosystem (Institute Straumann, Waldenburg, Switzerland), a new endosseous orthodontic implant anchor system for palatal anchorage. The Orthosystem may replace compliance dependent extraoral anchoring aids for orthodontics and makes a bonding of well aligned mandibular dentition and it's use with class II elastics unnecessary. The fixture is designed for a one‐stage application. It consists of an implant of pure titanium with a surface‐treated: screw‐shaped endosseous part of 3.3mm diameter and lengths of 4 and 6mm. Above the polished transmucosal neck follows an abutment where transpalatal arches made of rigid orthodontic wires (0.032×0.032inch) are fixed by means of a clamp‐cap. 6 patients with an angle class II malocclusion were implanted with the 6mm fixture in the proximal midsagittal region of the palate during a pilot study. The treatment goal was extraction of the first maxillary pre‐molars with subsequent retraction of the frontal dentition under maximal anchorage of the lateral teeth. For the implantation a simple surgical procedure of 10 min length was required while no further invasive actions are needed until explantation. This way the strain on the patients was reduced to a minimum. They are now at varying stages of active treatment and the most advanced case is demonstrated here. The clinical and radiological findings after 12 months of treatment comprising 3 months of healing revealed no implant mobility or dislocation, favourable peri‐implant soft tissue conditions, and no marked mesial movement of the implant supported teeth. The frontal dentition was retracted by 8mm with space closure occurring in a relatively short treatment period.
A survey on dental care and oral implantology in Beijing, China
Authors: Huasong Liu , Yang Hui , De Groot K.
Published: March 2003

In this article,we present a survey on dental care and oral implantology in Beijing, China. The Chinese population comprises 1.2 billion or about 20% of the world's population. This survey shows: (i) there is a well‐developed dental system in China, mostly operated by the Chinese government; (ii) in Beijing, there are 1328 dentists and oral surgeons and 515 special dental nurses working in dental departments of hospitals: (iii) about 2 million new patients visit the dentist every year; (iv) oral implantology is a new technology for the Chinese dentist and oral surgeon, as shown by the finding that in 1992, only 384 persons were treated with oral implants in a few hospitals in Beijing; however, most hospitals are interested in performing oral implantology in the near future; (v) imported implants are too expensive for Chinese patients, and therefore good qualified domestic implants and cheaper imported implants have a great market potential.
The biological effect of natural bone mineral on bone neoformation on the rabbit skull
Authors: Hämmerle Christoph H. F. , Olah Attila J. , Schmid J¨rg , Fl¨ckiger Lorenz , Gogolewski Sylwester , Winkler James R. , Lang Niklaus P.
Published: March 2003

The aim of this study was to evaluate the effect of deproteinized bovine bone graft material on new bone formation in a guided bone regeneration model system. In 20 rabbits, a periosteal skin flap was raised uncovering the calvaria. A form stable hemispherical dome made of polylactic acid (PLA) was placed onto the roughened calvaria. Prior to placement, the dome was either filled with peripheral blood alone (control group, 8 rabbits), or with blood and OsteoGraf®/N‐300 (test group, 12 rabbits). The wound was closed for primary healing. Morphometric assessment of 1‐ and 2‐month undecalcified histologic specimens revealed better tissue fill in the test domes at 1 month (test 99%, control 55%)(P<0.05) and 2 months (t. 100%;c, 82%). The fraction of the new bone within the regenerated tissue was higher in the test specimens at 1 month (t, 22%;c, 12%)(P<0.05) and 2 months (t, 34%;c, 24%). The fraction of the entire space underneath the domes occupied by bone was higher in the test at 1 month. but higher in the controls at 2 months. The fraction of the bone substitute material in contact with bone increased from 1 month (34%±14) to 2 months (45%±5). The surface fraction of osteoblast layers was tendentially higher in the test at 1 month but higher in the control specimens at 2 months. In both test and control, initially woven bone was formed which underwent subsequent remodeling. Cellular degradation of the deproteinized bone graft was frequently detected. It is concluded that deproteinized bovine bone mineral has osteo‐conductive properties and can initially accelerate new bone formation during guided bone regeneration by increased recruitment of osteoblasts.
The effect of a calcium hydroxide paste on wound healing and osseointegration of dental implants. A pilot study in beagle dogs.
Authors: Kohal Ralf‐J. , Hürzeler Markus B. , Schneider Steffen R. , Riede Urs N. , Caffesse Raul G.
Published: March 2003

The aim of this investigation was to evaluate the effect of a new calcium hydroxide suspension (Osteoinductal®) on the healing process of endosseous dental implants after placement. The material, composed of 25% calcium hydroxide, 25% Oleum pedum tauri and 50% vaselinum album, was developed with the intention to accelerate and to increase the mineralized bone to implant contact during the healing phase. Eight adult beagle dogs were used in this study. Prior to the beginning of the study the dogs had all mandibular premolars extracted. After the extraction sites had healed for 3 months. implant osteotomies were performed. On one side of the mandible Osteoinductal® was applied into the osteotomies before placement of the implants, whereas the other side did not receive Osteoinductal®. A total of 48 implants were placed with two losses during the entire study period. Two dogs were sacrificed 1 week, 2 weeks, 4 weeks and 3 months after implant placement. The specimens were evaluated histologically and histomorphometrically. In the histological evaluation an intense inflammatory reaction towards the calcium hydroxide suspension was found leading to a destruction of the bone surrounding the implants after 1 and 2 weeks. A giant cell reaction against the test material was visible at 4 weeks. At 3 months no inflammatory and no giant cell reaction could be depicted in the test group. The mean direct bone to implant contact or inflammatory tissue to implant contact showed no differences between test and control group for 1 and 2 weeks. Although statistically not significant, there was a clinical significant difference in the mineralized bone to implant contact between test and control group for the last two timepoints (i.e. 4‐week specimens: test group 2.3±0.9%, control group 26% 11.1%; 3‐month specimens: test group 10.5±12.7%, control group 60.7±13.7%). This study indicates that the use of the calcium hydroxide suspension Osteoinductal® has a detrimental effect on wound healing and osseointegration of dental imolants and cannot be 1 recommended for use with dental implants.
Five‐ to six‐year results of a prospective clinical trial using the ENDOPORE® dental implant and a mandibular overdenture
Authors: Deporter Douglas , Watson Philip , Pharoah Michael , Levy Dana , Todescan Reynaldo
Published: March 2003

This report is an update on a group of 46 clinical trial patients who each received 3 free‐standing Endopore® dental implants placed using a 2‐stage surgical approach in the anterior mandible. After an initial healing interval of 10 weeks, the implants were used in each case to retain an overdenture, and at the time of the report. all patients had passed 5 years of continuous function. The 5‐year cumulative “survival” rate based on a life table analysis was 93.4% and this remained unchanged after 6 years. The 5‐year “success rate” was 83.3% when assessed qualitatively with the published criteria of others using a four‐field table analysis categorizing every implant in the study as one of “Grade 1 Success”, “survival”, ”unaccounted for” or “failure”. Modified periodontal parameters verified continued peri‐implant soft tissue health. No implant still in function had more than 1.8 mm cumulative bone loss during the first 5 years of function. These results provide clear evidence that Endopore® implants despite their short lengths function at least as well as other dental implant 1 designs used in much longer lengths.
Three‐dimensional bone structure around hydroxyapatite and titanium implants in rabbits
Authors: Wigianto Rudi , Ichikawa Tetsuo , Kanitani Hideo , Kawamoto Naeko , Matsumoto Naoyuki , Ishizuka Hiroshi
Published: March 2003

Long‐term support of dental implants requires adequate bone thickness in the area surrounding the implant. A three‐dimensional examination, including calculations of percent boneGmplant contact and percent bone volume, was conducted to clarify the bone structure around pure titanium (Ti) and dense hydroxyapatite (HA) implants. The implants were installed in the tibiae of rabbits, and the bone structure was examined after 2, 4, 6 and 8 weeks. The bone formation following implantation differed in the cortical bone and cancellow bone areas. In the cortical bone area, the percent bone implant contact and percent bone volume were comparatively consistent for both Ti and HA implants during the observation period. In the cancellous bone area, both findings were influenced by the implantation period, and the chronological bone structure in the cancellous bone area also differed between Ti and HA implants. The percent bone‐implant contact and percent bone volume in the Ti implant increased over 8 weeks, whereas the dense HA implant increased for the first 4 weeks and then decreased. The implant materials, Ti and HA, affected the bone remodeling in the cancellous bone area.
Clinical outcome of autogenous bone blocks or guided bone regeneration with e‐PTFE membranes for the reconstruction of narrow edentulous ridges
Authors: Chiapasco Matteo , Abati Silvio , Romeo Eugenio , Vogel Giorgio
Published: March 2003

The aim of this study was to analyse the clinical outcome of two different surgical methods for the reconstruction of narrow edentulous ridges before implant installation: guided bone regeneration with e‐PTFE membranes and autologous bone chips or grafting of autologous bone blocks without e‐PTFE membranes. Thirty partially edentulous patients, presenting insufficient bone width (less than 4 mm) in the edentulous sites for installation of screw‐type titanium implants, were selected and assigned to two different treatment modalities. Fifteen patients (group 1) were treated by means of guided bone regeneration with e‐PTFE membranes supported by stainless steel wews and autologous bone chips taken from intraoral sites. Fifteen patients (group 2) were treated by means of autologous bone blocks taken from intraoral or extraoral sites (anterior iliac crest and calvaria) and stabilized with titanium microscrews. Six to 8 months later, during re‐entry for implant insertion, the gain of ridge width obtained was measured. In group 1 the average amount of bone gain was 2.7 mm, whereas in group 2 the value was 4.0 mm. Five to 6 months after implant placement prosthetic rehabilitation was started. The mean follow‐up after prosthetic load has been 22.4 months. Success rates of implants according to Albrektsson criteria has been 93.3% in group 1, and 90.9% in group 2. Although a statistical comparison between the two treatment modalities may not be feasible, due to the bias resulting from the choice of treatment by the clinician and from the differences in donor sites and defect extension, some considerations can be made: 1) both methods are a reliable means for the correction of narrow edentulous ridges; 2) both techniques necessitate overcorrection of the defect because of interposition of connective tissue beneath the membrane in the first group and bone resorption in the second one; 3) the use of semipermeable barriers increases the costs of the surgical procedure, as compared to bone grafting without membranes; 4) guided bone regeneration presents a higher risk of infection because of wound dehiscence and membrane exposure. Therefore, in case ofwide edentulous areas, reconstruction of narrow ridges should be performed with bone blocks without membranes.
The accuracy of spiral tomography to assess bone quantity for the preoperative planning of implants in the posterior maxilla
Authors: Serhal Charbel Bou , Jacobs Reinhilde , Persoons Marc , Hermans Robert , Van Steenberghe Daniel
Published: March 2003

When planning to place implants in the posterior region of the maxilla, the location of the maxillary sinus floor is influencing the available bone height and the implant length chosen. The aim of the present study was to evaluate in vitro the spiral tomographic technique that could be used for pre‐operative implant planning. Tomographs were taken of 6 dry human skulls using the Cranex Tome® multifunctional unit (Orion Corporation Soredex, Helsinki, Finland). Three sites were selected in the left posterior maxilla and marked with gutta percha meaning a total of 18 sites (6×3=18) for interpretation. Bone height and width were measured on the tomographs and after sectioning also on the skulls. The values obtained from the measurements on tomographs were divided by an enlargement factor of 1.5 (as defined by the manufacturer) and then compared with those from the real measurements on the skulls. Real measurements were on average 0.24 mm (SD 0.19) lower than the tomographic measurements (P<0.05). From the present results it could be concluded that spiral tomography using the recently developed Cranex Tome® reveals sufficient information and detail for pre‐operative planning of a limited edentulous region.
Effect of total body irradiation on peri‐implant tissue reaction: an experimental study
Authors: Renou S. J. , Guglielmotti M. B. , De La Torre A. , Cabrini R. L.
Published: March 2003

Abstract: The aim of the present study was to evaluate the osseointegration process under total body irradiation conditions (LD 50/30). Twenty Wistar rats (mean body weight: 90 g) were used. Under ethyl urethane intraperitoneal anesthesia (1 g/kg body weight), the animals were irradiated with a single 700 cGy dose (linear accelerator 6 Mev photons). Four days post irradiation, a titanium laminar implant was placed in the left tibia of each rat. Antibiotic therapy (ceftriaxone) was administered daily post implantation, to prevent infection by radiation. Fourteen days post implantation, the animals were killed by ether overdose. The tibiae were resected, radiographed and processed for embedding in methyl methacrylate. The results showed impaired osteogenesis and absence of osseointegration in experimental tibiae. This could be due to a direct action of total body irradiation on osteogenesis precursor cells. This effect would impair bone formation involved in peri‐implant osseointegration processes in this experimental model.
Morbidity of chin bone harvesting
Authors: Raghoebar Gerry M. , Louwerse Charlotte , Kalk Wouter W. I. , Vissink Arjan
Published: March 2003

Abstract: The chin is a very common donor site for autogenous bone grafts. The aim of this retrospective study was to evaluate long‐term morbidity of the donor site following chin bone graft harvesting. One to three years after grafting of local bone defects of the anterior maxilla with chin bone, 21 patients were recalled for objective assessment of any residual morbidity at the harvesting area. Morbidity as well as satisfaction of the patients were evaluated by a survey of the medical record, a mail‐in questionnaire, and a standardized physical examination. The outcome of this study showed that there was good acceptance of the chin bone harvesting procedure. The objective morbidity was low, but subjectively almost half of the patients reported a changed (decreased) sensibility in the harvesting area. This subjective change in sensibility did not result in noteworthy complaints or discomfort by the patients, however. Although bone harvesting from the chin is generally considered as a good option for reconstruction of local bony defects, the patients should be informed about the potential hazard of a changed sensibility in the chin region.
A prospective randomized study comparing two techniques of bone augmentation: onlay graft alone or associated with a membrane
Authors: Antoun Hadi , Sitbon Jean Max , Martinez Henri , Missika Patrick
Published: March 2003

Abstract: Two techniques of ridge augmentation using onlay bone graft alone or associated with a non‐resorbable membrane have been previously described. This prospective, randomized study compared these two techniques at 6 months, in terms of bone gain, resorption and quality obtained at edentulous sites. Osseous measurements were taken using stents, callipers and CT‐scans. Membrane exposure occurred at one site, 4 weeks after placement. Endosseous implants were successfully placed at all grafted sites. The mean graft thickness for all subjects was 4.7 mm (range: 2.3–6.2 mm). Overall mean resorption was 1.5 mm (range: 0–4.6 mm) whereas overall mean width gain was 3.2 mm (range: 0.8–6.2 mm). Six months following surgery, the membrane group experienced significantly less bone resorption than the graft alone group (P<0.01). Width augmentation did not differ significantly between the two groups. In conclusion, combining a membrane with an onlay graft demonstrates less bone resorption with a minimal risk of complications. Longer follow‐up is needed to confirm the benefits of using a non‐resorbable membrane.
Anisotropic elasticity of cortical and cancellous bone in the posterior mandible increases peri‐implant stress and strain under oblique loading
Authors: O'Mahony Aisling M. , Williams John L. , Spencer Paulette
Published: March 2003

Abstract: The aim of this study was to compare implant‐bone interface stresses and peri‐implant principal strains in anisotropic versus isotropic three‐dimensional finite element models of an osseointegrated implant in the posterior mandible. We obtained anisotropic (transversely isotropic) elastic constants for mandibular bone and derived equivalent isotropic constants by averaging over all possible spatial orientations. A finite element model was constructed using ten‐node tetrahedral p‐elements, providing curved edges where necessary and increasing the accuracy of the results in regions of high stress gradients. Perfect bonding was assumed at the implant‐bone interface. An oblique load was applied at the coronal aspect of the crown with 100 N vertical and 20 N bucco‐to‐lingual components. Implant‐bone interface stresses exceeded reported bond strengths and principal strains reached yield strain levels in the cortical crest. Anisotropy increased what were already high levels of stress and strain in the isotropic case by 20 to 30% in the cortical crest. In cancellous bone, anisotropy increased what were relatively low levels of interface stress in the isotropic case by three‐ to four‐fold to exceed bond strength levels. Anisotropy has subtle, yet significant effects on interface stresses and peri‐implant strains and careful consideration should be given to its use in finite element studies of dental implants.
Implant osseointegration in the irradiated mandible
Authors: Brogniez Véronique , Nyssen‐Behets Catherine , Grégoire Vincent , Reychler Hervé , Lengelé Benoît
Published: March 2003

Abstract: This research focuses on the effects of radiotherapy on the osseointegration of dental implants placed before or after radiotherapy in 11 male beagles. After the extraction of all mandibular premolars 1st and 2nd molars, three dogs were implanted without radiotherapy (Control group), four dogs were irradiated 4 weeks after implantation (IrA group) and four dogs were irradiated 8 weeks before implantation (IrB group). Eight implants were placed in each dog, in an alternating pattern: four nonsubmerged ITI Bonefit® titanium plasma spray‐coated and four submerged Steri‐Oss® hydroxyapatite‐coated. The irradiated dogs received 4.3 Gy daily for 10 days. Two different fluorescent markers were administered at the time of implantation and of irradiation. The dogs were sacrificed 6 months after implantation, i.e. 5 months after radiotherapy for the IrA group and 8 months for the IrB group. Each mandible was submitted to histological and microradiographic analysis. Bone formation occurred around 85 of the 88 implants and consisted mostly of the successive deposit of woven and lamellar bone. Both irradiated groups showed obvious bone remodeling in alveolar bone as well as in the basilar part of the mandible. Nevertheless, in the IrA group, the resorption phenomena predominated over osteogenesis. The balance between these two opposite processes seemed to be restored 8 months after the end of radiotherapy (IrB group). In spite of focal lesions of radiation‐specific bone destruction emphasized in some irradiated dogs, we conclude from our results that osseointegration of dental implants is possible in irradiated bone tissue.
Healing of marginal defects at implants placed in fresh extraction sockets or after 4–6 weeks of healing
Authors: Nemcovsky Carlos E. , Artzi Zvi , Moses Ofer , Gelernter Ilana
Published: March 2003

Abstract: The purpose of this study was to evaluate the clinical healing of buccal marginal defects around implants placed in fresh extraction sockets or after several weeks together with barrier membranes and bone graft. Two implant placement protocols were compared: delayed‐immediate sites primarily closed by a rotated (full thickness) palatal flap (RPF) at the time of tooth extraction and implantation after 4–6 weeks (Group 1, 24 patients, n = 31 implants) and immediate procedures (into fresh extraction sockets) primarily closed by a rotated split palatal flap (RSPF) (Group 2, 19 patients, n = 23 implants). One or two proximal maxillary implants were simultaneously placed. Height and width of the marginal defect were measured at the time of implant placement and after 6–8 months, at second stage surgery. For Groups 1 and 2, the mean percentage of the reduced defect height was 91.2% (± 9.12) and 77.4% (± 16.92), respectively, and the mean percentage area of the reduced defect was 97.2% (± 3.85) and 90.2% (± 9.15), respectively. Differences between groups were statistically significant. Groups were subdivided according to number of implants placed (one or two). Spontaneous implant cover screw exposure was seen only in Group 2. There was an association between the number of implants simultaneously placed and the occurrence of spontaneous exposure. The mean percentage reduction of the defect height and area was significantly smaller where there was spontaneous exposure. Significant differences were found for mean percentage reduction of the defect height and area only between the two implant subgroups within each group.
Randomized multicenter comparison of two coatings of intramobile cylinder implants in 313 partially edentulous mandibles followed up for 5 years
Authors: Mau Jochen , Behneke Alexandra , Behneke Nikolaus , Fritzemeier Claus Udo , Gomez‐Roman German , D'Hoedt Bernd , Spiekermann Hubertus , Strunz Volker , Yong Mei
Published: March 2003

Abstract: Intramobile cylinder (IMZ) implants with either of two coatings, hydroxyapatite (HA) or titanium plasma‐flame (TPF), as distal abutments for combined tooth implant‐supported restorations, were compared in 313 partially edentulous mandibles with respect to postprosthetical failure patterns and complication frequencies in a randomized multicenter clinical trial. Within the treatment protocols, the two coatings do not show evidence of different efficacy with respect to occurrence of postprosthetical integration deficiency (ID) or functional deficiency (FD). Statistical equivalence for an absolute effect of ±15% inevent‐free survival could only be demonstrated for FD, not for ID, however. Intent‐to‐treat and per‐protocol population analyses gave consistent results. Hazards of occurrence of ID and FD, adjusted for years of follow‐up, were estimated for ID as 7% per year (95%CI 4‐10% per year) with HA and 5% per year (95%CI 3‐7% per year) with TPF, and for FD as 5% per year (95%CI 3‐7% per year) with HA and 4% per year (95%CI 2‐6% per year) with TPF. The 5‐year cumulative success rates for no ID were 69.5% (95%CI 58‐81%) with HA and 82.2% (95%CI 74‐91%) with TPF. With respect to frequencies of complications, there was no relevant statistically significant difference between the two coatings.
Comparative effects of quaternary ammonium mouthrinses on 4‐day plaque regrowth
Authors: Moran J. , Addy M. , Jackson R. , Newcombe R. G.
Published: March 2003

Background: Quaternary ammonium compounds constitute a large group of antibacterial chemicals with a potential for inhibiting plaque and gingivitis. One compound, benzalkonium chloride (BC), may be of value, although there is a dearth of evidence to support efficacy. The aim of this study was to measure the ability of 2 BC mouthrinses (0.05% and 0.1%) to inhibit de novo plaque reformation.

Method: A 4‐day plaque regrowth model. For comparative purposes, a commercial mouthrinse containing cetyl pyridinium chloride (CPC) and a positive control chlorhexidine (CX) mouthrinse were also evaluated.

Results: Compared to water control, a reduction in plaque scores of 52% was noted for the CX mouthrinse, 22.5% for CPC and 5% and 6% for the 2 BC rinses. For plaque area, reductions of 84%, 47%, 16% and 15% were found for CX, CPC, and the 2 BC rinses, respectively. Significant reductions in plaque area compared to the water rinse were also seen with the 2 BC rinses (p<0.05). However, for both plaque score and plaque area, the CX and CPC rinses significantly reduced plaque compared to the BC rinses (p<0.0001).

Conclusions: These findings would suggest that the 2 benzalkonium rinses would only have a limited value at inhibiting plaque formation.
Guided tissue regeneration procedure with bioresorbable membranes versus conventional flap surgery in the treatment of infrabony periodontal defects
Authors: Ratka‐Krüger P. , Neukranz E. , Raetzke P.
Published: March 2003

Aim:

Claims are being made that clinical results of periodontal flap surgery are enchanced when membranes are employed to aid GTR in intrabony pockets. It was the aim of our study to determine whether this assumption was true for a certain bioresorbable membrane (Guidor® Matrix Barrier).

Method: 44 intrabony defects were treated in 16 patients. In 21 lesions, conventional flap surgery only was performed, while in 23, similar lesion membranes were placed as an additional treatment task. Results were evaluated over a time span of 12 months.

Results: In all surgical areas, treatment resulted in significant improvement of parameters such as attachment levels and probing depths, as well as index values for plaque and bleeding on probing. This occurred whether membranes had been used or not, without any significant differences when comparing the collective results of both treatment groups.

Conclusions: Placement of membranes during periodontal surgery for the enhancement of tissue regeneration in intrabony pockets is often both difficult and time consuming. In the light of our clinical results with resorbable membranes, such extra effort seems hardly warranted.
Healing following GTR treatment of bone defects distal to mandibular 2nd molars after surgical removal of impacted 3rd molars
Authors: Karapataki Sofia , Hugoson Anders , Kugelberg Carl F.
Published: March 2003

Aim: The purpose of this study was to study the healing, following guided tissue regeneration (GTR) treatment, of bone defects distal to mandibular 2nd molars (M2s) after surgical removal of impacted mesioangularly or horizontally inclined third molars (M3s) in patients 25 years.

Method: 20 patients with bilateral soft tissue impacted M3s were included in the split‐mouth study. The 2 sites to be treated in each patient were randomised before the 1st operation as to which would undergo the test procedure and which would be the control site. After surgical removal of M3 at test sites, a resorbable polylactic acid (PLA) barrier was attached to M2 to cover the post‐surgical bone defect. The flap was then replaced and sutured to cover the barrier. Control sites underwent the same procedure, as did the test sites, with the exception that no barrier was placed. The clinical examinations performed were oral hygiene pre‐ and 12 months postoperatively and probing pocket depth 12 months postoperatively. The alveolar bone level (ABL) at the distal surface of the M2, as determined from radiographs taken at suture removal and 12 months postsurgery, was chosen to be the primary response variable.

Results: Most bone defects showed healing up to 10%–20% of the tooth length at both test and control sites. 2 test and 2 control sites showed no improvement in the bone level. The mean values of bone healing registered in mm from the cemento‐enamel junction (CEJ) were 2.6±2.19 SD and 3.0±2.20 SD for test and control sites, respectively. Different factors affecting the healing result are discussed.