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Biomedical subjects

S Abati

Publications and source records attributed to S Abati.

At least 19 recordsLinked to original sources
PubMed2000

Behavior of implants in bone grafts or free flaps after tumor resection.

The authors compared bone resorption of autogenous bone grafts and revascularized free flaps used for the reconstruction of mandibular continuity defects following resection for tumors, before and after the placement of endosseous implants. Ten patients (group 1) were treated with autogenous bone grafts taken from the fibula or the anterior iliac crest; 8 patients (group 2) were treated with iliac or fibula revascularized flaps. Four to 8 months later, 72 endosseous implants were placed in the reconstructed areas. After a further healing period of 4-6 months, patients were rehabilitated with implant-borne prostheses. The following parameters were evaluated and compared between the two groups: 1) bone resorption of grafts and free flaps before and after implant placement; 2) peri-implant bone resorption mesial and distal to each implant, immediately after prosthetic rehabilitation and then during yearly follow-ups. Bone resorption before implant placement showed mean values of 3.53 mm in group 1, and 0.96 mm in group 2. Peri-implant bone resorption was: 0.49 mm (39 implants) in group 1, and 0.45 mm (30 implants) in group 2, at time of prosthetic rehabilitation; 0.78 mm (39 implants) in group 1, and 0.89 mm (30 implants) in group 2, 12 months after prosthetic load; 1.16 mm (24 implants) in group 1, and 1.02 mm (13 implants) in group 2, 24 months after the prosthetic load. A significant difference in bone resorption before implant placement was found between the two groups, whereas it was not found after implant placement and prosthetic load. The failure rate according to Albrektsson criteria was 4.9% (2/41 implants) in group 1, and was 3.2% (1/31) in group 2.

Adult↗
PubMed1999

Clinical outcome of autogenous bone blocks or guided bone regeneration with e-PTFE membranes for the reconstruction of narrow edentulous ridges.

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 screws 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 of wide edentulous areas, reconstruction of narrow ridges should be performed with bone blocks without membranes.

Adult↗
PubMed1991

[An assessment of the proliferative activity in oral lichen planus].

The author's aim was to evaluate the cell proliferation of oral lichen planus, by an in vitro labelling technique using tritiated thymidine (TLI). For this purpose six patients with oral lichen planus and six control volunteers with oral mucosa clinically sound were studied. The cell kinetic parameter was investigated by counting cells from autoradiographs on histological sections of the biopsies. Significant differences were found between the basal TLI of the two group (p = 0.002) but no between the epithelial TLI (Wilcoxon test).

Biopsy↗
PubMed1990

[Study of cellular kinetics in oral leukoplakia].

The Authors aim was to study the Labeling Indices (LI) of 12 subjects with oral leukoplakia, using an in vitro labeling technique with tritiated thymidine (Silvestrini-Kit, Ribbon spa, Milan). Twelve volunteers of our Dental Clinic were enrolled in this study as a control group. The kinetic parameter was investigated by counting cells from autoradiographs on histological selections of the biopsies. By a Wilcoxon test, significant differences were found between the LI of the two groups: p = 0.00003. Finally, a comparison has also been made between LI of these lesions and the LI of oral squamous cell carcinomas.

Adult↗
PubMed1989

Early plaque colonization on human cementum.

We have described the morphology of developing plaque on cementum in an in vivo human model. Slabs of cementum obtained from sound teeth, rendered anorganic with 5% sodium hypochlorite, were glued to orthodontic brackets and positioned on the upper canines, premolars and molars in 8 volunteers. The brackets were removed after 2, 4, 8, 24 h and processed for scanning electron microscopy (SEM). Within 2 h, a thin pellicle covered the cementum surface, with few micro-organisms detectable. At 4 and 8 h, coccoid plaques were present. Filaments inserted perpendicularly to the plaque surface were seen at 24 h. The results indicate that early bacterial colonization of human cementum is a selective process, mediated by an organic pellicle and mainly involves cocci.

Bacteria↗
PubMed1989

Periodontitis in a patient with chronic neutropenia.

The aim of this investigation was to obtain information about the composition and the morphology of the microorganisms that inhabit the root surface of a patient with chronic neutropenia and severe and progressive periodontitis. In addition, gingival biopsies were studied by both scanning and transmission electron microscopy (SEM and TEM) to look for bacteria within the gingiva. Dark field microscopy (DFM) revealed 50% spirochetes, 30% motile rods, and 20% coccoid forms. Fourteen extracted teeth studied by SEM showed that the distribution of different bacterial morphotypes varies along the root surface and spirochetes are the prevailing bacteria on the most apically located plaque. TEM analyses of gingival tissue revealed no bacterial invasion within the gingiva. This study suggests that spirochetes may play an important role in the etiology of periodontitis associated with chronic neutropenia. In spite of neutropenic status, there was no bacterial invasion into the gingiva, suggesting that host reaction to dental plaque has not been abolished in this condition.

Adult↗
PubMed1989

[Amount of mineralized tissue removed by root planing].

The Author's aim was to determine the amount of mineralized tissues removed during root planing conducted by means of a curette, using a profilometer. Records were kept at time 0 and after 4 cycles of 5 strokes each. Mean values of final records show that the average of tissue removal, expressed in microns, was greater than the mean thickness of cementum in the instrumented areas.

Dental Cementum↗
PubMed1988

The role of scanning electron microscopy in periodontal research.

During recent years a great amount of research has led to a better understanding of the etiology, pathogenesis and pattern of progression of periodontal diseases. Scanning electron microscopy (SEM) has contributed to this improvement, mainly with respect to histology of periodontal tissues, the description of the morphology and distribution of bacteria on the exposed root surface, analysis of the host-parasite interactions on the gingival pocket wall, and morphological evaluation of root treatment. This review deals with all these topics. Unusual types of SEM research are also described and discussed. Uncommon sample preparation techniques for SEM in periodontal research are described. SEM in periodontal research should be of great application in the near future. Cathodoluminescence, back-scattered emission and immunolabelling techniques will be formidable tools in this field of dentistry.

Gingiva↗
PubMedDate not supplied

Oral health profile in an institutionalized population of Italian adults with mental retardation.

The oral health of 219 residents with mental retardation living in a long-term-care institution near Milan was assessed. The dental and periodontal status, daily habits, oral hygiene, and oral mucosal status were evaluated. Of the sample, 179 (81.7%) were males. The mean age of the residents was 61.3 years, and the degree of cooperation was evaluated as good for 131 subjects (59.8%), fair for 79 (36.1%), and poor for nine (4.1%). The percentage of residents who were edentulous was 21.5% (47 subjects), of whom 28 subjects (59.6%) were without dentures. Evaluation showed an overall DMFT of 23.1, and the average number of missing teeth was 20.5. All subjects had periodontal disease: Forty-five subjects had calculus and/or shallow pockets (4-5 mm); 61 had deep pockets (> or = 6 mm). The most common mucosal lesion was oral stomatitis (49.3%). These findings underline the need for special programs aimed at institutionalized subjects with mental retardation.

Adult↗
PubMedDate not supplied

Implant-retained mandibular overdentures with Brånemark System MKII implants: a prospective comparative study between delayed and immediate loading.

This study was designed to compare the results of immediate and delayed loading of implants with implant-retained mandibular overdentures. Ten patients (test group) received 40 Brånemark System MKII implants (4 per patient) placed in the interforaminal area of the mandible. Standard abutments were immediately screwed to the implants, rigidly connected with a bar, and immediately loaded with an overdenture. Ten patients (control group) received the same type and number of implants in the same area, but the implants were left to heal submerged. Four to 8 months later, standard abutments were screwed to the implants and the same prosthetic procedure was applied. Each implant was evaluated at the time of prosthetic loading and at 6, 12, and 24 months after the initial prosthetic load with the following parameters: modified Plaque Index (MPI), modified Bleeding Index (MBI), probing depth (PD), and Periotest. Peri-implant bone resorption was evaluated on panoramic radiographs taken 12 and 24 months after initial prosthetic loading. No significant differences were found between the 2 groups regarding MPI, MBI, Periotest, peri-implant bone resorption, and PD at 6 and 24 months (P > .05). The only difference was found regarding PD values on the mesial and lingual sites at 12 months (P < .05). The cumulative success rate of implants was 97.5% in both groups. Results from this study showed that immediate loading of endosseous implants rigidly connected with a U-shaped bar does not seem to have any detrimental effect on osseointegration. Conversely, this method significantly shortens the duration of treatment with relevant satisfaction for the patients.

Adult↗
PubMedDate not supplied

[Morphological surface analysis of nickel-titanium wires. Preliminary SEM observations].

Authors studied with Scanning Electron Microscopy (SEM) the surface morphology of new manufactured orthodontic arches made of rectangular NiTi wires. All the wires exhibite various patterns of superficial defects such as scratches and pits. Results suggest to further investigate the changes of wire surfaces subsequent to their use in oral environment and sterilization procedures.

Dental Alloys↗