The role of bone decortication in enhancing the results of guided bone regeneration: a literature review.

BACKGROUND: Bone decortication is often performed as part of a guided bone regeneration (GBR) procedure. The biologic rationale for decortication of bone is to allow progenitor cells easy access to a GBR-treated site and to facilitate prompt angiogenesis. It also may enhance the physical connection between a bone graft and a recipient site. However, the concept of decortication prior to a GBR procedure is controversial because there are no human clinical trials to support its effectiveness, and there are opposing points of view derived from animal studies regarding its usefulness. METHODS: The literature was assessed to determine whether there are enough data to validate the rationale for using decortication of bone as an integral part of GBR procedures. Eight searches were performed seeking controlled clinical trials that addressed the ability of decortication to enhance GBR. RESULTS: Three controlled animal clinical trials were found that supported the use of decortication prior to performing GBR. Two controlled animal clinical trials were located that indicated decortication did not improve GBR procedures. No human controlled clinical trial was identified that addressed the ability of decortication to alter GBR procedures. The literature addressing the capacity of decortication to affect onlay grafting or wound healing also provided mixed results. CONCLUSION: There is conflicting information and not enough clinical trials to make a definitive determination as to the merits of bone decortication prior to GBR procedures.

Evaluation of the oxyrase OxyPlate anaerobe incubation system.

The Oxyrase OxyPlate anaerobe incubation system was evaluated for its ability to support the growth of clinically significant anaerobic bacteria previously identified by the Anaerobe Reference Laboratory at the Centers for Disease Control and Prevention. The results were compared with those obtained with conventional anaerobe blood agar plates incubated in an anaerobe chamber. We tested 251 anaerobic bacterial strains. Plates were read at 24, 48, and 72 h; growth was scored by a numerical coding system that combines the degree of growth and the colony size. Organisms (number of strains tested) used in this study were Actinomyces (32), Anaerobiospirillum (8), Bacteroides (39), Campylobacter (8), Clostridium (96), Fusobacterium (12), Leptotrichia (8), Mobiluncus (8), Peptostreptococcus (16), and Propionibacterium (24). At 24 h, 101 (40.2%) of the 251 strains tested showed better growth with the anaerobe chamber than with the OxyPlate system, 10 (4.1%) showed better growth with the OxyPlate system, and the remaining 140 (55. 8%) showed equal growth with both systems. At 48 h, 173 (68.9%) showed equal growth with both systems, while 78 (31.1%) showed better growth with the anaerobe chamber. At 72 h, 176 (70.1%) showed equal growth with both systems, while 75 (29.9%) showed better growth with the anaerobe chamber. The OxyPlate system performed well for the most commonly isolated anaerobes but was inadequate for some strains. These results indicate that the Oxyrase OxyPlate system was effective in creating an anaerobic atmosphere and supporting the growth of anaerobic bacteria within 72 h. OxyPlates would be a useful addition to the clinical microbiology laboratory lacking resources for traditional anaerobic culturing techniques.

Evaluation of the BBL Crystal Anaerobe identification system.

The BBL Crystal Anaerobe (ANR) identification system was evaluated, and the results were compared with those from conventional anaerobic methods. We tested 322 clinically significant anaerobic bacteria according to the manufacturer's instructions. The system identified correctly 286 of 322 (88.8%) of the anaerobic bacteria tested. Of these, 263 of 322 (81.7%) were identified correctly on initial testing and 49 were identified correctly only to the genus level; on repeat testing, 23 of 49 (46.9%) were identified correctly to both the genus and the species levels. A total of 26 (8.5%) were misidentified at the species level, and 10 (3.1%) were not identified. Performance characteristics for individual strains varied. The system correctly identified all tested strains of Campylobacter, Desulfomonas, Desulfovibrio, Leptotrichia, Mobiluncus, Peptostreptococcus, Porphyromonas, Provetella, Propionibacterium, Tisierella, and Veillonella and 36 of 37 (97.3%) Actinomyces strains, 42 of 46 (91.3%) B. fragilis group strains, 79 of 103 (76.7%) Clostridium strains, (however, the system failed to identify any of the 7 C. innocuum and 9 C. tetani strains tested), and 8 of 15 (53.3%) Bacteroides strains. This system was easy to use, did not involve the addition of reagents, and was faster than conventional anaerobic procedures. It would be a useful addition to the anaerobe laboratory of most hospitals.

Effects of carbodiimide crosslinking and load environment on the remodeling of collagen scaffolds.

Tissue engineering aims to develop clinical prostheses that are ultimately replaced by a functional, cell-produced matrix. For this goal to be achieved, the material must not only perform all the critical functions of the lost tissue immediately upon implantation, but also be replaced with new tissue at such a rate that tissue integrity is maintained. In the present study, prostheses formed from reconstituted collagen fibers were crosslinked to various levels with a carbodiimide; the same implant material was shown to be perceived in a variety of ways by its host. Variously crosslinked constructs were implanted in rats. Lightly crosslinked collagen fabrics implanted in abdominal wall defects remodeled into a fascia-like material within 90 days, in contrast to heavily crosslinked fabrics that were still persistent at this time point with little new tissue ingrowth and a marked foreign body reaction. However, the remodeling response was found to be site dependent, as heavily crosslinked collagen scaffolds implanted as anterior cruciate ligament (ACL) replacements in a dog model were adequately replaced by functional neoligamentous structures within 12 weeks.

Collagen fabrics as biomaterials.

Tissue-engineered implants require appropriate biomaterials to serve the required physical function of the tissue being repaired or replaced while facilitating remodeling of the implant. We report on the development of implantable fabrics manufactured from continuous collagen threads. The collagen threads are formed by extrusion of native, acid-extracted bovine collagen into a buffered solution of polyethylene glycol, followed by rinsing and air drying. The high manufacturing rate of such threads permits the production of collagen fabrics of various configurations. The fiber diameter can be controlled, and threads with dry diameters as low as 25 microm have been produced. Braids and bundles of collagen threads implanted as a replacement of the anterior cruciate ligament in a dog model were completely remodeled into host tissue by 12 weeks. Knitted collagen fabrics implanted in a rat abdominal repair model prevented herniation, and connective tissue ingrowth was observed within the fabric by 12 weeks.

Typing of Clostridium difficile by western immunoblotting with 10 different antisera.

Western blotting (immunoblotting) with antisera against each of 10 reference serogroups was evaluated as a means of typing Clostridium difficile. A total of 164 clinical isolates of C. difficile were tested. Variations in band profiles in each serogroup were used to type isolates into subserogroups. This technique was useful for an epidemiological investigation.

[Recurrent ventricular tachycardia due to hydatic cyst of the heart. Recovery after surgical resection. Report of one case]. / Tachycardie ventriculaire récidivante par kyste hydatique du coeur. Guérison après résection chirurgicale. Rapport d'un cas

Report of the case-history of a 66 year-old woman in whom the diagnosis of ventricular aneurysm was reached in 1958 during a systematic X-ray examination, while the electrocardiogram suggested a lateral-wall infarction with no anginal pain. After fifteen years of a practically asymptomatic course there were practically uninterrupted attacks of ventricular tachycardia. Coronary angiography and left ventriculography excluded the hypothesis of an aneurysm and suggested the diagnosis to cystic tumour of the left ventricle. A voluminous hydatic cyst was removed surgically. Ventricular arrhythmia did not recur since.