PubMed Health⌕ Search

Biomedical subjects

G Brunel

Publications and source records attributed to G Brunel.

At least 19 recordsLinked to original sources
PubMed2007

Antimicrobial peptide modulation in a differentiated reconstructed gingival epithelium.

Gingival innate immunity has been studied by using biopsies and normal or transformed epithelial cell monolayers. To overcome individual biological variabilities and as a physiological alternative, we have proposed using a reconstructed tissue equivalent. In this study, we investigated the functionality and the stage of differentiation of a reconstructed human gingival epithelium. We also characterized this epithelium at the molecular level to investigate its differentiation stage compared with native human gingival epithelium. The expression levels and localization of markers related to proteins and lipids of well-differentiated stratified epithelium, such as cytokeratins, cornified envelope proteins and enzymes, or to factors in lipid synthesis and trafficking were examined. Immunohistochemistry revealed similar localization patterns in both types of epithelia and mRNA quantification showed a close resemblance of their expression profiles. We further revealed that, like native gingiva, reconstructed gingival epithelium was able to respond to pro-inflammatory or lipopolysaccharide stimuli by producing antimicrobial peptides hbetaD-2, hbetaD-3 or LL-37. Finally, we demonstrated that reconstructed human gingival epithelium, as a model, was good enough to be proposed as a functional equivalent for native human gingival epithelium in order to study the regulation of gingival innate immunity against periodontal infections.

Antimicrobial Cationic Peptides↗
PubMed2003

General organization of the human intra-masseteric aponeuroses: changes with ageing.

A magnetic resonance imaging (MRI) study of the layout of the aponeurotic layers of the masseter muscle was done on a series of 18 patients, aged from 6 to 79 years. The study was undertaken in parallel with a study on 169 cadavers to correlate the anatomical dissection and MRI findings. The aims were as follows. On the cadavers, the results of dissection were compared with the results of MRI: the layer-by-layer dissections and the anatomical dissections of the different spatial planes have shown that the masseter muscle displays a penniform structure typically characterized by the presence of alternating muscular/aponeurotic layers. The anatomical sections and the MRI section in the same plane allowed the appearance of the intra-muscular aponeurotic layers on MRI to be defined. The patients were then divided into four age cohorts, and the arrangement and variations of the human masseter muscle defined as a function of age. This double study has brought new elements to the understanding of the timing of the development of the intra-muscular aponeurotic structures and the modifications which they undergo with ageing. It appears that the aponeurotic structures only become individually identifiable towards the age of 17 years and that ageing is accompanied by a reduction in the transverse muscular mass accompanied by a verticalization of the aponeurotic layers.

Adolescent↗
PubMed2001

Bioabsorbable materials for guided bone regeneration prior to implant placement and 7-year follow-up: report of 14 cases.

BACKGROUND: The purpose of the present study was to evaluate the efficacy of a guided bone regeneration (GBR) procedure prior to implant placement and the long-term outcome of the inserted implants. METHODS: Prior to dental implant placement, GBR procedure was performed on 14 patients (mean age 48 years) using a synthetic hydroxyapatite (HA) spacer under a collagen membrane. After a mean healing period of 8 months, bone biopsies were obtained during the placement of 14 implants. The specimens were processed for histology without demineralization in order to assess bone quality and quantity of the regenerated bone. RESULTS: Both the bone density and the resorption degree of HA particles were relatively varied between samples. The different phenotypes of osteoclasts and multinucleated giant cells and the individual host response could partially explain the unpredictable results in terms of bone remodeling and biomaterial resorption. However, the presence of HA particles in the regenerated bone had no influence on the osseointegration of implants presenting a success rate of 86% after a 7-year observation period. CONCLUSIONS: These results confirm the possibility of regenerating bone by means of bioabsorbable materials, assuring at the same time the long-term success for implants inserted in regenerated sites.

Absorbable Implants↗
PubMed2001

[Simplification and rationalization of oral implantology].

A number of rules, often considered as dogmas by some, made it possible for oral implants to achieve a high success rate. However, some of these concepts have been questioned. Indeed, the submerged fashion of implant placement, the arbitrary 3 to 6 months healing period, bicortical anchorage, placement of the longest possible implants, as well as implant placement in strict sterile conditions have been scientifically challenged. The aim of this article is thus to give a critical review of these concepts, in order to further simplify and rationalize oral implantology, putting this field in the reach of a bigger number of patients and practitioners. However, procedural simplification in oral implantology is not synonymous to poor patient preparation. On the contrary, an in-depth knowledge and experience in both the surgical and prosthetic aspects of oral implantology are of utmost importance in order to achieve a high success rate.

Dental Implantation, Endosseous↗
PubMed2000

Histologic analysis of a fractured implant: a case report.

This study presents the histologic analysis of an implant retrieved 14 months after loading because of a fracture in the collar region. The implant (Biovent) was removed with part of the periimplant tissues, and the block was prepared using cutting and grinding equipment to obtain 3 sections approximately 30 microns thick. The examination evidenced a high degree of osseointegration, with a bone-to-implant contact of 74% +/- 13%. The lamellar bone was dense and in close relation with the hydroxyapatite coating of the implant. The connection between the 0.4-mm hydroxyapatite coating and the metal was always very tight. The thickness of the metal at the break point was assessed to be 1.6 mm. Besides the relative weakness of the metal at the neck of the implant, other possible causes of failure are discussed.

Biocompatible Materials↗
PubMed2000

Use of Emdogain in the treatment of deep intrabony defects: 12-month clinical results. Histologic and radiographic evaluation.

The objective of this study was to evaluate the application of an enamel matrix derivative (Emdogain) in deep periodontal pocket therapy. Twenty-one patients presenting intrabony and interproximal defects that could be treated with guided tissue regeneration were selected. The intrabony defects were divided into deep (< 9 mm) and very deep (> or = 9 mm) defects. Bleeding on probing, Plaque Index, probing pocket depth, mobility index, gingival recession, probing attachment level, and surgical bone level were measured at baseline. At 12 months, cases were reexamined and indices recorded again. The mean probing depth decreased from 8.1 +/- 2.1 mm to 3.2 +/- 1.5 mm; attachment level decreased from 10.4 +/- 2.4 mm to 7.0 +/- 1.8 mm; recession increased from 2.3 +/- 1.4 mm to 3.8 +/- 1.8 mm; and surgical bone level decreased from 9.6 +/- 1.9 mm to 7.1 +/- 1.5 mm. No significant difference wa noted between bone defects with one or 2 walls, between local and generalized periodontitis, or between smokers and nonsmokers. Significant statistical difference was found, however, between deep intrabony defects and very deep defects when attachment gain was considered. No adverse reaction to the substance was noted. The good clinical results obtained were not confirmed by radiologic results; standardized and computerized radiographs at 12 months did not reveal significant improvement. The histologic examination carried out on 2 samples did not show evidence of new attachment. Further studies are necessary to clarify the action mechanism and to evaluate the long-term results of this method.

Adult↗
PubMed1998

Guided bone regeneration for immediate non-submerged implant placement using bioabsorbable materials in Beagle dogs.

The aim of the present study was to evaluate the combined application of different bioabsorbable materials for healing of residual peri-implant defects after placement of non-submerged implants into fresh extraction sockets. Second and third mandibular premolars were extracted from 10 Beagle dogs, the coronal part of the distal sockets were surgically enlarged and this was followed by immediate placement of specially designed hollow-screw non-submerged dental implants. For each animal, the coronal peri-implant defects were further treated with one of the 4 following procedures: 1) no treatment, control site; 2) grafting with porous hydroxyapatite (HA); 3) collagen membrane tightly secured around the implant and over the defect and 4) grafting with HA covered with a collagen membrane. After 16 weeks of healing, specimens were removed from the mandibule and prepared for a histomorphometric evaluation. The bone-to-implant contact length (BIC) was measured and compared amongst the different treatment modalities. In the defect area, the irregular bone regeneration was similar between all the treatment procedures (P > 0.10). In the sites covered with a collagen membrane alone, the total BIC (47%) was greater than in control sites (28.7%, P < 0.05) or sites grafted with HA (22.2%, P < 0.02). Total BIC in sites treated with the HA-membrane combination (43%) was only significantly different from sites treated with HA (P < 0.05). It is concluded that the use of bioabsorbable materials results in a limited increase of osseointegration when used in conjunction with immediate placement of non-submerged implants, although the principle of the one stage surgical approach can be maintained.

Absorbable Implants↗
PubMed1998

Evaluation of a diphenylphosphorylazide-crosslinked collagen membrane for guided bone regeneration in mandibular defects in rats.

In the present study, the potential of a diphenylphosphorylazide-crosslinked type I bovine collagen membrane was evaluated in the healing of mandibular bone defects applying the biological concept of guided bone regeneration. The experiment was carried out on 25 Wistar rats. After exposing the mandibular ramus bilaterally, 5 mm diameter full-thickness circular bone defects were surgically created. While the defect on one side was covered by the membrane (experimental), the defect on the other side was left uncovered (control) before closure of the overlying soft tissues. The rats were sacrificed in groups of 5 after 7, 15, 30, 90, and 180 days of healing. Although at early stages of healing similar amounts of bone formation were observed in the experimental and control defects, after 1 month of healing, most of the experimental defects were completely closed with new bone, while in the control defects, only limited amounts of new bone were observed at the rims and in the lingual aspect of the lesions. In the 90- and 180-day animals, all experimental defects were completely closed, while in the control defects, no statistically significant increase in bone regeneration was observed. The increase in percentage of bone regeneration in the experimental defects was statistically significant between the 15-day specimens as compared with the 7-day specimens (P < 0.01) and likewise between 30-day and 15-day specimens (P < 0.001). It can be concluded that a DPPA-crosslinked collagen membrane yields biocompatibility, ad hoc mechanical hindrance, and handling characteristics suitable for guided bone regeneration applications in this experimental model.

Alveolar Bone Loss↗
PubMed1998

A 2-year clinical evaluation of a diphenylphosphorylazide-cross-linked collagen membrane for the treatment of buccal gingival recession.

To retard collagen membrane enzymatic degradation and to increase its mechanical strength, the diphenylphosphorylazide (DPPA) technique has been demonstrated to achieve natural cross-links between peptide chains of collagen without leaving any foreign product in the cross-linked molecule. In the present prospective clinical trial, the potential of a DPPA-cross-linked type I bovine collagen membrane was evaluated in the healing of 15 buccal soft tissue recessions in 15 patients according to the biological concept of guided tissue regeneration. The recession decreased from 3.7 mm (SD 1.4) at baseline to 0.8 mm (SD 1.2) at 2 years postsurgery, corresponding to a mean root coverage of 82.2% (P <0.0001). Concurrently, the clinical attachment level decreased from 5.4 mm (SD 1.6) at baseline to 1.9 mm (SD 1.2) 2 years postsurgery, corresponding to an average clinical attachment gain of 3.5 mm (SD 1.3) (P <0.0001). The 2-year postsurgical width of the keratinized tissue was not significantly different from baseline values. More than half (53%) of the treated sites showed complete root coverage and about two-thirds (73%) of the total cases showed a 75% to 100% disappearance of the mucogingival defect. The present investigation demonstrated that the use of DPPA-cross-linked collagen membranes in the treatment of human buccal soft tissue recessions results in predictable amounts of root coverage and clinical attachment gain. Long-term randomization controlled clinical trials of this material are needed to fully evaluate its potential for treating periodontal recession.

Adult↗
PubMed1997

Guided tissue regeneration using a collagen membrane in chronic adult and rapidly progressive periodontitis patients in the treatment of 3-wall intrabony defects.

This study, confined to non-smokers, evaluated guided tissue regeneration using a diphenylphosphorylazide-cross-linked bovine type I collagen membrane in deep 3-wall intrabony defects in 52 adult periodontitis (AP) and 16-rapidly progressive periodontitis (RPP) patients, previously treated for the acute phase of the disease, no more than one defect being randomly selected for each patient. Before surgery and 6 months after surgery, plaque (PI) and sulcus bleeding (SBI) indices, as well as probing pocket depths (PPD), gingival margin locations (GML) and probing attachment levels (PAL) were recorded. During the post-surgical period, the membranes were very well tolerated in all patients and PI and SBI were kept at a low level. 6 months post-surgical, there was a significant gain in PAL (3.6 mm for AP; 2.6 mm for RPP) and reduction in PPD (5.5 mm for AP; 4.1 mm for RPP) for both groups of patients (p < 0.05). However, neither the change in GML (1.9 mm for AP; 1.5 mm for RPP), nor PPD or PAL yielded a statistically significant difference between AP and RPP patients. The results of this study demonstrated that the treatment of deep 3-wall intrabony defects with a diphenylphosphorylazide-cross-linked collagen membrane in both AP and RPP patients during the quiescent phase of the disease is a treatment modality where the conquences are predictable. However, longer observation periods are necessary to evaluate the stability of the improvements obtained for the 2 groups of patients and the differences between them.

Adult↗
PubMed1997

Combined collagen membrane and hydroxyapatite/collagen chondroitin-sulfate spacer placement in the treatment of 2-wall intrabony defects in chronic adult and rapidly progressive periodontitis patients.

This study, confined to non-smokers, evaluated guided-tissue regeneration in deep 2-wall intrabony defects using a diphenylphosphorylazide-cross-linked bovine type I collagen membrane supported by a hydroxyapatite/collagen/chondroitin-sulfate spacer in 43 adult periodontitis (AP) and 14 rapidly progressive periodontitis (RPP) patients, no more than 1 defect being randomly selected for each patient. Before surgery and 6 months after surgery, plaque (PI) and sulcus bleeding (SBI) indices, probing pocket depths (PPD), gingival margin locations (GML) and probing attachment levels (PAL) were recorded. During the post-surgical period, the biomaterials were well tolerated in all patients and PI and SBI were kept at a low level. Following therapy, there was a significant gain in PAL (4.2 mm for AP; 3 mm for RPP) and reduction in PPD (6.1 mm for AP; 4.7 mm for RPP) for both groups of patients (p < 0.05). A significantly greater gain in PAL and reduction in PPD were observed for AP compared to RPP patients (p < 0.05). The change in GML was not statistically different between groups (1.8 mm for AP; 1.6 mm for RPP). It is concluded that the combined use of a diphenylphosphorylazide-cross-linked bovine type-I collagen membrane, supported by a hydroxyapatite/collagen/chondroitin-sulfate spacer, is beneficial in improving PAL and reducing PPD in 2-wall intrabony defects in both AP and RPP patients during the quiescent phase of the disease, with statistically better results for the former group. However, longer observation periods are necessary to evaluate the stability of the improvements obtained by this combined treatment approach between and for each group of patients.

Adult↗
PubMed1997

Guided tissue regeneration employing a collagen membrane in a human periodontal bone defect: a histologic evaluation.

The purpose of this study is to confirm histologically whether a new attachment can be obtained around a tooth by guided tissue regeneration using bioresorbable barrier. The test tooth was a maxillary molar with an intrabony pocket. At reentry 5 months after periodontal surgery, a hard, whitish, blood-free tissue was found to fill the original defect. Histologic analysis revealed presence of new bone, cementum, and periodontal ligament compatible with the expected histologic result of guided tissue regeneration techniques with barrier membrane.

Absorption↗
PubMed1996

Regeneration of rat calvarial defects using a bioabsorbable membrane technique: influence of collagen cross-linking.

The aim of the present study was to examine the influence of cross-linking on collagen membranes used for guided bone regeneration of calvarial defects in rats. In 48 Wistar rats, divided equally into 4 groups, 1 control and 3 experimental, standardized transosseous circular calvarial defects were made midparietally. In the control group, the defect was only covered by the soft tissue flap while in the 3 experimental groups, 3 differently cross-linked collagen membranes were interposed between the osseous defect and the overlying flap before suturing. The healing was assessed at 10, 20, and 30 days after surgery. The results showed that augmenting the degree of collagen cross-linking diminished the membrane resorption rate. Compared to the sham-operated sites, the membrane protected defects showed significantly more bone regeneration (on average 4 times more) as attested by histology and measured by histomorphometric analysis. Although the bone gain seemed to augment with increasing degrees of cross-linking, the results within the 3 experimental groups were not statistically different. Since longer healing periods might have been necessary to substantiate results within experimental groups, a study is currently undertaken to evaluate this aspect. This study demonstrated the efficacy of collagen membranes in guiding bone regeneration, as well as the importance of the type and degree of cross-linking.

Analysis of Variance↗
PubMed1990

[A practical method for the surgical uncovering of a buried implant].

This method puts forward a new and easy process to uncover an endosseous implant before the prosthetic rehabilitation. We use a "punch", a dermatologist's instrument, composed of two parts: a plastic handle and a cylinder blade. We choose the diameter's blade instrument according to the diameter of implant and we change the punch for each implant to clear. The punch is held like a pencil, vertically. The punch goes deep into the gum to the bone and is turned simultaneous. A perfect cylinder part of gum is filled out. In case of propitious circumstances, this method is safe quick and avoids doing a second flap.

Dental Implantation, Endosseous↗
PubMed1989

[Nonsurgical treatment: a long-term study].

This retrospective study was carried out on 20 patients with periodontal lesions treated by the same operator by scaling root planing. The investigation was designed to study the variability of the level of attachments through different charts of probing before and after treatment over a period of 5 years maintenance. Through efficient scaling and root planing different results were obtained according to sites of different localisations and depth. It shows the uncertain and occasional characteristics of periodontal lesions, and gives useful informations for treatment choices and regular maintenance program.

Dental Prophylaxis↗
PubMed1989

[A practical method for the determination of the available bone height in oral implantology].

This method puts forward a new and quick process to fix the available height of bone in the recipient site of an endosseous implant. With a flexible strip containing a lot of small equidistant gauged steel spheres, we can quickly reckon up the height of bone. The strip having been placed in the mouth, the patient bites it during the panoramic X-ray examination. The diameter of the spheres is known. On the X-ray photography we can easily measure the spheres and then reckon the available height of bone in the recipient site. This method presents many advantages: the anatomical conditions in the recipient site (specially the height of bone) are known very quickly, in case of contra-indication, this method gets the practitioner out of prescribing new X-ray examinations. So we consider that it is an economical process, an X-ray examination is always realizable with the strip. It is an easy work comparing with TDM.

Alveolar Process↗