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Biomedical subjects

S Matarasso

Publications and source records attributed to S Matarasso.

At least 19 recordsLinked to original sources
PubMed2000

Bone regeneration using Bioglass: an experimental study in rabbit tibia.

Bioglass (BG) has been shown recently to be osteoconductive and osteopromotive in different experimental and clinical conditions. The aim of the present study was to evaluate BG particles in bone defects in rabbit tibia. In control sites, bone was observed only in the peripheral areas of the defects, while in test sites, newly formed bone was found around all BG particles, even those located in the central portion of the defect. Osteoblasts were actively secreting osteoid matrix directly on the granules' surface. BG seems to be a highly osteoconductive material.

Animals↗
PubMed1999

A microscopical evaluation of 24 retrieved failed hollow implants.

Twenty-four hollow ITI implants (four screws, and 20 cylinders) were retrieved because of failure, and evaluated in our laboratory, in a eight-year period (1989-1996), to see if a common cause could be observed in this implant design. No selection of these implants was carried out, and they represented the total number of implants of this type received in the above-mentioned time frame. The implants had been inserted by several different clinicians and were received from four universities and a private practice. The implants had been removed for mobility, pain, and presence of a vertical bone loss. About two-thirds of the implants were unstable in the jaw at the time of retrieval. Twenty implants had been used as single implants restoration and four in bridge reconstructions. Most of our specimens showed that the inflammatory process had reached the hollow portion of the implants. The following microscopical features were present in almost all our specimens: calculus and plaque on the coronal portion of the implant surface, presence of proliferating epithelium and of bone sequestra, and presence of bone apically to the inflammatory process. Perhaps, when the inflammatory process reaches the implant hollow portion, the infection runs a more rapid course due to the scarce vascularity of the bone inside this part.

Dental Implants↗
PubMed1998

Early tissue reactions to polylactic acid resorbable membranes: a histological and histochemical study in rabbit.

The aim of this study, in rabbit tibia, was an evaluation of the early reactions of the tissues to the insertion of polylactic membranes, used in connection with titanium implants. The specimens were retrieved after 1-4 weeks, and a histological analysis was performed. It was possible to see that, in the early implantation phases, no degradation of the macrostructure of the membrane was present. On the outer portion of the membrane many multinucleated giant cells (MGC) were present and membrane fragments were present inside the cytoplasm of these cells. These cells could explain the inflammatory processes reported, in some reports, with the use of materials made by polylactic and polyglycolic acid. We did not observe detrimental effects in the bone tissue around the membrane, and the membrane appeared to have a mechanical stability for the time necessary for bone regeneration.

Animals↗
PubMed1998

Hollow implants retrieved for fracture: a light and scanning electron microscope analysis of 4 cases.

One of the possible complications of implant treatment is the occurrence of an implant fracture. Metal fatigue and biomechanical overload seem to be the most common causes of fractured implants. This study evaluated 4 implants (3 hollow cylinders and 1 hollow screw) which fractured after a mean loading period of 2.8 years. All implants had a 4 mm diameter and had been inserted in a posterior location. In 3 cases parafunctional habits were present. In all cases a vertical resorption of the peri-implant bone was present. The endosseous portion of the implant presented always a very high bone-implant contact percentage. Scanning electron microscopic examination showed that at least one of the implant holes was involved in the fracture line; no porosities or material defects were observed on the fractured surface of the implant. In hollow implants the holes could represent a site of less resistance.

Alveolar Bone Loss↗
PubMed1998

Guided tissue regeneration versus coronally repositioned flap in the treatment of recession with double papillae.

Twenty buccogingival recessions (3 mm deep) in twenty patients were selected and divided into two groups. Periodontal parameters were recorded (recession reduction, probing depth, clinical attachment level, and keratinized tissue width), and both groups were treated with regenerative therapy using a resorbable polylactic acid membrane. The test group was treated using the double papilla flap procedure, and the control group was treated using the coronally repositioned flap procedure. The results obtained at a 1-year follow-up were comparable between the test and control groups for recession reduction, probing depth, and clinical attachment level, although the test group obtained a very large amount of keratinized gingiva (+74.7%) compared to the control group.

Absorbable Implants↗
PubMed1996

Histological evaluation of the peri-implant bone around plasma-sprayed non-submerged titanium implants retrieved from man: a report of two cases.

Two cases of non-submerged implants are reported: one was removed, unloaded, after 1 year, for psychiatric reasons, and the other, after a loading period of 4 years, for a fracture of the implant. The implants and surrounding tissues were processed to obtain thin ground sections. In the first case compact lamellar bone was observed in close contact with the titanium all around the implant perimeter. No connective tissue or empty spaces were found at the bone-implant interface. Histochemical staining with von Kossa demonstrated that all the bone around the implant was highly mineralized. No areas of osteoid tissue were found at the bone-implant interface. In the implant retrieved due to fracture it was possible to observe a very high percentage of bone-implant contact.

Adsorption↗
PubMed1996

Evaluation of guided bone regeneration in rabbit tibia using bioresorbable and non-resorbable membranes.

The aim of this study was an evaluation of the possibility of bone regeneration in connection with implant placement, using a new bioresorbable membrane (Guidor Matrix Barrier) used previously in periodontal tissues regeneration. The study compared the bone regeneration obtained around Bonefit-ITI implants inserted in rabbit tibia using Guidor membranes, Gore-Tex membranes and in control sites. Microscopic analysis was performed after 6, 9 and 12 weeks. It was possible to see that the amount of bone around implants covered by Guidor and Gore-Tex membranes was roughly equivalent in all experimental sites at the 6-, 9- and 12-week time intervals. Also, all control sites healed completely. It could be concluded from this study that: (1) rabbit tibia cannot be recommended in research connected with guided bone regeneration, as all control sites healed in the same way as the test sites; (2) in no case did the presence or the degradation of the resorbable membrane prevent the formation of new bone; (3) no inflammatory reaction was present around the bioresorbable and the non-resorbable membranes; (4) bone formed in all cases on the outer surface of the non-resorbable membranes; (5) large Guidor membrane fragments were present in the 6-week specimens, while in the 12-week specimens only small fragments were recognizable; (6) Guidor membranes can be used in guided bone regeneration.

Animals↗
PubMed1996

Maintenance of implants: an in vitro study of titanium implant surface modifications subsequent to the application of different prophylaxis procedures.

The aim of the present study was to evaluate surface alterations on titanium implant necks subsequent to different prophylaxis procedures. Fifty ITI implants were utilized. Forty implants were treated with 10 different prophylaxis procedures (ultrasonic scaler, plastic tip ultrasonic scaler, stainless steel curette, titanium curette, teflon curette, air powered system, abrasive rubber cups, polishing rubber cup and brush), and 10 implants were left as untreated controls. Surface alterations were studied on an area of 1 mm x 0.9 mm and quantified using optical microscopic, SEM and laser prophylometer analysis. The use of laser prophylometer provided an objective criterion for evaluation, expressing implant neck surface alterations in numeric values in terms of two roughness indexes, Ra and Rz. The results showed that, in comparison with the controls (Ra = 0.50; Rz = 3.98) the procedures investigated could be divided into 3 main groups: 1) Methods which altered the implant neck surface producing increased roughness (Ra = 0.68-2.08; Rz = 4.68-11.92); 2) Methods which left the implant neck surface unaltered (Ra = 0.44-0.57; Rz = 0.42-3.46); 3) Methods resulting in a smoothening of the implant neck surface (Ra = 0.36; Rz = 2.15). Group 1 included procedures that should be avoided. However, it appeared safe to apply the procedures of groups 2 and 3. To confirm these results, it will be necessary to evaluate the plaque- and calculus-removing efficacy from titanium neck implant surfaces in vivo.

Air↗
PubMed1996

Juvenile hyaline fibromatosis of gingiva: a case report.

Juvenile hyaline fibromatosis is an extremely rare inherited condition, probably resulting from an inborn error of metabolism. It is characterized by cutaneous nodules, gingival hypertrophy and joint contractions. It affects children but usually it is not present at birth, and is microscopically characterized by a conspicuous hyalinization of the connective tissue.

Child↗
PubMed1996

Cellular colonization and bone formation into expanded polytetrafluoroethylene membranes: a light microscopical and histochemical time course study in the rabbit.

We report on a time course study of cellular colonization of expanded polytetrafluoroethylene (ePTFE) membranes in rabbits. Bone defects (8 mm) were prepared with low speed burs in rabbit tibial metaphyses and covered with ePTFE membranes. The membranes were retrieved after 3, 6, 9, and 12 weeks. At 3 weeks, all membranes were filled by cells and osteoid tissue: no mineralized tissue was found. Osteoblasts positive for alkaline phosphatase (ALP) were observed on the outer surface and inside the material interstices of the membrane. At 6 weeks, it was possible to observe an increase of the quantity of the osteoid material inside the membranes. At 9 weeks, bone tissue was present and it usually originated from the most external part of the membrane, and spread to the central part of the membrane. Only the central portion of this bone appeared to be completely mineralized. A sharp decrease in the number of ALP-positive osteoblasts was observed. At 12 weeks, the quantity of bone present appeared to be substantially increased. Only a small percentage of the bone inside the membrane appeared to be completely mineralized. No cells positive to acid phosphatase were observed. These histological results confirm the high biocompatibility of ePTFE membranes and the bone formation inside the ePTFE interconnected nodes could, probably, help in achieving a good biomaterial-tissue integration with predictable results in bone regeneration.

Alkaline Phosphatase↗
PubMed1991

Blood in saliva of HIV seropositive drug abusers: possible implication in AIDS transmission.

We have studied hemoglobin concentration in saliva of anti-HIV positive and anti-HIV negative intravenous drug abusers (IVDA) and normal controls and the relationship between hemoglobin concentration in saliva and number of CD4+ cells and clinical status of AIDS in anti-HIV positive IVDA. 120 anti-HIV positive IVDA, 112 anti-HIV negative IVDA and 116 normal healthy subjects not belonging to any risk group for HIV infection completed the study. Saliva was collected at awakening before brushing teeth and the concentration of hemoglobin was determined. Hemoglobin concentration in saliva in basal conditions is higher in anti-HIV positive IVDA with respect to anti-HIV negative IVDA (p less than 0.05) and controls (p less than 0.01). In anti-HIV positive IVDA hemoglobin concentration in saliva is higher in subjects with CD4+ cells less than 200/10(6) l with respect to subjects with CD4+ greater than 200/10(6) l (p less than 0.05) and in subjects with ARC/AIDS with respect to subjects with PGL or who are asymptomatic (p less than 0.01). Subjects with ARC/AIDS have a mean concentration of hemoglobin of 19 micrograms/0.1 ml saliva (range 0-153) which corresponds to 1.3 microliters of blood/ml saliva. If 10 ml of saliva are exchanged during kissing an average of 13 microliters of blood are transferred (110 microliters of whole blood at extreme range). Blood of symptomatic patients has an HIV titer of 7 TCID/microliters which for 10 ml saliva containing an average of 1.3 microliters blood/ml saliva corresponds to an average of 90 TCID (770 TCID at the extreme range).(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1991

[The role of Langerhans cells in periodontal disease].

Following a morphological description of Langerhans cells, the paper analyses their functional activity both as phagocytic cells and as antigen-presenting cells. The role of this cell population in periodontal disease is the examined in the light of recently reported findings.

Antigen-Presenting Cells↗
PubMed1991

[The role of phagocytic cells in periodontal disease].

Having described the morphological and functional characteristics of phagocytic cells, the paper underlines that, in addition to the etiological responsibility of bacterial plaque, the main role in the onset and evolution of periodontitis is played by the host's response. Phagocytic response plays a fundamental role in the host's defence reaction and represents the first barrier to the penetration of bacteria into periodontal tissue. In addition to their defensive role, phagocytic cells may also be responsible for damage to periodontal tissue as a collateral effect of their phagocytic function, thus worsening the periodontal lesion.

Granulocytes↗
PubMed1991

[The role of LGL cells (NK and K) in periodontal disease].

The paper reports the morphological and functional aspects of NK and K cells in the light of the most recent advances in the field, and pays particular attention to their cytotoxic and suppressor capacities. The role of NK and K cells in periodontal disease is then described and it is observed how this cell population is absent in healthy gums, whereas it is found with increasing frequency at disease reaches the chronic stage. The presence of LGL cells is therefore thought to be associated with the development of plaque-induced inflammation.

Humans↗
PubMed1991

[An epidemiological study on dental-periodontal pathology in a sample of the school-age population of the city of Naples. I. Periodontal pathology].

The paper reports the results of a study of the prevalence of periodontal diseases found in a sample group, aged between 6 and 18, resident in Naples. The structure of the survey, the clinical methods of collecting data and the statistical processing of data were carried out according to WHO directives regarding the study of oral pathologies.

Adolescent↗