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Biomedical subjects

L Sbordone

Publications and source records attributed to L Sbordone.

At least 19 recordsLinked to original sources
PubMed2003

Behavior of SaOS-2 cells cultured on different titanium surfaces.

Surface properties may affect the clinical outcome of titanium dental implants. The aim of the present study was to investigate the effects of 3 different titanium surfaces-smooth (S), sandblasted (SB), and titanium plasma-sprayed (TPS)-on proliferation, differentiation, and apoptosis of human osteoblast-like cells, SaOS-2. Cell proliferation was significantly (p < 0.05) higher on the S surface, and synthesis of extracellular matrix proteins was more abundant on TPS and SB than on S surfaces. Analysis of integrin receptors showed a higher expression of alpha2, alpha5, alphaVbeta3, and ss1 on TPS as compared with SB and S surfaces. An increase in alkaline phosphatase activity was detected only on SB and TPS surfaces. Analysis of cell apoptosis did not demonstrate any significant difference among the 3 different surfaces. The results indicate that titanium surface topography affects proliferation and differentiation of osteoblast-like SaOS-2 cells, suggesting that surface properties might be important for bone response around dental implants in vivo.

Alkaline Phosphatase↗
PubMed2002

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the osteoblastic differentiation of the human osteosarcoma cell line SaOS-2.

The Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) is a hematopoietic growth factor that regulates the in vitro and in vivo proliferation and differentiation of hematopoietic cells through the interaction with a specific heterodimeric receptor complex (GM-CSFR), consisting of an alpha and a beta chain with molecular weights of 80 and 120 KDa, respectively. We have studied the expression of the GM-CSFR (alpha chain) on the surface of the human osteosarcoma cell line SaOS-2 and the in vitro effects of different concentrations (10, 100, and 200 ng/ml) of GM-CSF on GM-CSFR expression and the biological activity of SaOS-2 cells. Our data show that SaOS-2 cells express GM-CSFR and that GM-CSF can down-regulate the expression of its own receptor on these cells. Furthermore, to evaluate the biological effects of GM-CSF on SaOS-2 cells, we have investigated cell proliferation and differentiation of these cells treated with different doses of the growth factor through: (1) a morphological analysis of typical osteoblast differentiation markers such as osteopontin and BSP-II; (2) measurement of alkaline phosphatase (ALP) activity; (3) production of bone ECM components (collagen I, fibronectin, tenascin, and laminin); (4) production of interleukin-6 (IL-6) and osteocalcin in the culture medium. The results show that the in vitro treatment of SaOS-2 cells with recombinant human GM-CSF causes a decreased cell proliferation and an increased production of osteopontin, BSP-II, ALP, IL-6, and most but not all ECM components. These findings suggest that GM-CSF can regulate proliferation and differentiation of osteoblast-like SaOS-2 cells and could also play an unexpected role in the maturation of bone tissue.

Bone Neoplasms↗
PubMed2002

[Periodontal disease and occlusal trauma: a still debated controversy? A review of the literature].

In the "Glossary of Periodontics Terms" written by the American Academy of Periodontology, the occlusal trauma is defined as "an injury to the attachment apparatus as a result of excessive occlusal forces". Nowadays, the effects of occlusal trauma on tooth support tissues, the onset and the progression of periodontal disease are still debated: many commonplaces have been disproved, but some doubts and not yet clear points remain, even owing to the difficult diagnosis of the presence and the real clinical impact of a traumatic occlusion. Then, ethical reasons prevent researchers from prospective clinical trials. At the beginning of the last century occlusal trauma has been supposed to be an etiologic factor of "alveolar pyorrhea", but several studies attending more strict scientific criteria failed to prove such correlation. On the basis of the bacterial genesis of periodontal disease, researchers started evaluating the possible effects of occlusal discrepancies on incidence, progression and treatment outcomes of periodontitis, but all the results underlined the more relevant role played by micro-organisms. The present review of the literature runs through this controversy again, analysing the most significant studies published.

Dental Occlusion, Traumatic↗
PubMed2002

[Biofilms of the oral cavity. Formation, development and involvement in the onset of diseases related to bacterial plaque increase].

Biofilm is defined as a community of bacteria intimately associated with each other and included within an exopolymer matrix: this biological unit exhibits its own properties, quite different in comparison with those showed by the single species in planktonic form. The oral cavity appears as an open ecosystem, with a dynamic balance between the entrance of microrganisms, colonisation modalities and host defences aimed to their removal: to avoid elimination, bacteria need to adhere to either hard dental surfaces or epithelial surfaces. The oral biofilm formation and development, and the inside selection of specific microrganisms have been correlated with the most common oral pathologies, such as dental caries, periodontal disease and peri-implantitis. Many of these bacteria are usual saprophytes of the oral environment, that, in particular situations, can overcome and express their virulence factors: to better understand the mechanisms of these pathologies it's necessary to know the complex interactions between all the bacterial species inside the biofilm and host tissues and responses. The present paper is a review of the most significant studies on the biofilm development modalities, their correlations with either health or illness of the oral cavity, the bacterial co-aggregation strategies and the biofilm response to antimicrobial agents.

Anti-Bacterial Agents↗
PubMed2000

[Bacterial virulence in the etiology of periodontal diseases].

Strong relationships have been very often described between various form of periodontal disease (PD) and certain bacterial species, so that nowadays periodontal disease is recognized as an infectious disease. Destruction of periodontal supporting tissues happens as a response to very intricate host-parasite interactions. When the clinician will be able to fully understand and identify such phenomena it would be possible to succeed in a properly diagnosis and control of the active phase of periodontal disease. The first step in such a direction would be to analyze the common characteristic of some bacterial species, the so called suspected periodontopathogens. Such species namely Gram-negative, associated with the outbreak of periodontal disease have in common the capacity to disrupt the integrity of the host defences by means of the so called virulence factors. These factors may enhance the bacterial colonization or may interfere with the host response that ultimately results in periodontal support breakdown. The present review focuses on the virulence factors of the main suspected periodontopathogens evaluating the effects on the host immune response and directly on the periodontal tissues.

Aggregatibacter actinomycetemcomitans↗
PubMed1999

A clinical comparison of the efficacy and efficiency of two professional prophylaxis procedures in orthodontic patients.

This study compared the efficacy and efficiency of two professional prophylaxis procedures in orthodontic patients performing different oral hygiene regimens: the air powder polishing system (APP), and the rubber cup and pumice (RCP) technique. Sixty-two patients were divided into two groups: group I included 40 subjects who did not use any chlorhexidine mouthwash and group II comprised 22 subjects who regularly rinsed with a chlorhexidine mouthwash (at a 0.12 per cent concentration) and showed increased tooth staining. Using a split-mouth experimental design, the buccal and lingual tooth surfaces were cleaned in half of the mouth by the APP and in the opposite half by the RCP technique. Tooth surfaces were scored before (PRE) and after (POST) the experimental procedures for the plaque index (PI), and for the presence of tooth staining. In addition, the treatment time required by each procedure was recorded. In test group I, significant reductions in the PI after APP and RCP were observed. Likewise, in test group II, both procedures significantly reduced the baseline PI values. In both experimental groups, the percentage of stained sites significantly decreased after APP and RCP, but in test group II, APP seemed to be more effective than RCP. In addition, APP required significantly less time than RCP to remove dental plaque and staining. These data show that both professional prophylaxis procedures are effective in orthodontic patients, with APP being the most time-efficient technique and the most effective method for removal of tooth staining.

Chlorhexidine↗
PubMed1999

Longitudinal study of dental implants in a periodontally compromised population.

BACKGROUND: The purpose of this longitudinal study was to determine the clinical status and the composition of the subgingival microbiota of dental implants and natural teeth in patients with a history of periodontitis. METHODS: Twenty-five partially edentulous patients treated for moderate to advanced adult periodontitis and having a total of 42 implants participated in this 3-year study. The assessment of clinical status was done 1, 2, and 3 years after prosthetic loading (T1, T2, and T3, respectively). Clinical parameters evaluated included probing depth (PD), clinical attachment level (CAL), gingival index (GI), and plaque index (PI). The subgingival microbiota at peri-implant and periodontal sites were analyzed at T1 and T2. RESULTS: No significant difference in clinical parameters between implants and teeth and within the 2 groups between different time points was observed through the study. PD and CAL measurements of sampled periodontal and peri-implant sites did not show any statistically significant difference through the study and between the 2 groups. PI of sampled periodontal sites showed a statistically significant improvement during the study. From the morphological observation of the subgingival microbiota, a significant difference in the composition of motile rods between implants and teeth was found at T1. There were no differences detected in the subgingival microbiota, culturally identified at peri-implant and periodontal sites for the duration of the study. CONCLUSIONS: In conclusion, implants were colonized by the indigenous periodontal microbiota and were well maintained in patients with a history of periodontitis. No significant association between progressing or non-progressing periodontal or peri-implant sampled sites in terms of loss of attachment and infection with at least one of the searched periodontal pathogens was found, suggesting that the presence of putative periodontopathogens at peri-implant and periodontal sites may not be associated with future attachment loss or implant failure.

Adult↗
PubMed1999

Microbiotica associated with refractory periodontis. Prevalence and antibiotic susceptibility.

BACKGROUND: The aim of the present study was to analyze the composition of subgingival microflora in patients with refractory periodontitis and to evaluate the antimicrobial sensitivity of isolated periodontopathic microorganisms to different antibiotics. METHODS: Eleven subjects with a mean age of 46.4 years were selected for the present study. All had been treated for periodontal disease in the past. After further disease progression patients were included in this study. Eight subgingival plaque samples per patients were collected for cultural analysis. RESULTS: "Black pigmenting anaerobic bacilli" were the pathogenic microorganisms more frequently isolated. The findings from antibiotic susceptibility test showed that high number of bacteria associated with refractory periodontitis resulted resistant to erythromycin, metronidazole and tetracycline. The most effective antibiotics were ciprofloxacin, amoxicillin-metronidazole and amoxicillin-clavulanic acid. CONCLUSIONS: Microbiological analysis and antibiotic susceptibility test should be considered important tools in the management of patients with poor clinical response to conventional periodontal treatment.

Anti-Bacterial Agents↗
PubMed1999

Bacterial colonisation during GTR treatment. A longitudinal analysis.

UNLABELLED: The purpose of the present study was to evaluate the long-term biological and clinical effects of a controlled delivery system releasing tetracyclines during the healing of interproximal periodontal defects treated by the technique of guided tissue regeneration (GTR) using e-PTFE membranes. METHODS: Fifteen patients, each with two comparable interproximal periodontal defects, underwent surgical treatment with e-PTFE membranes in conjunction with tetracycline fibres at the test site and e-PTFE membranes alone at the control site. Microbiological specimens were taken from each site treated at baseline (T0) and one year after surgery (T4). Plaque index (PI), gingival index (GI), pocket depth at probing (PD) and attachment level at probing (PAL) were recorded at baseline (T0) and one year after surgery (T4). The presence of selected pathogenic microbial species, Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium Nucleatum (Fn) and Actinobaccillus Actinomicetemcomitans (Aa), was investigated and these species were identified by cultural methods. RESULTS: No statistically significant difference in the level of periodontal pathogens was detected between the test and control sites at time T4. Likewise, no significant clinical difference between the test site and the control site was detected at time T4. CONCLUSIONS: The results suggest that tetracycline fibres used in conjunction with e-PTFE membranes do not provide and further clinical and microbiological improvement or effect the healing of periodontal defects one year after GTR treatment.

Anti-Bacterial Agents↗
PubMed1998

Periodontal status and subgingival microbiota of insulin-dependent juvenile diabetics: a 3-year longitudinal study.

This study examined for 3 years the changes in periodontal status and the possible correlations with selected subgingival microbiota and diabetic conditions in a group of 16 insulin-dependent diabetes mellitus (IDDM, JD) patients as compared with their 16 healthy cohabiting siblings (HS). JD patients were monitored every 3 months for levels of glycosylated hemoglobin (HbA1C). Clinical and microbiological parameters were measured 6 weeks before drawing blood to determine levels of HbA1C. Periodontal parameters were measured at baseline (TO), year 2 (T2), year 3 (T3) and included: probing depth (PD), attachment level (AL), sulcus bleeding index (SBI), and plaque index (PI). Two sites in each patient were selected for microbial samples: a mesio-facial aspect of the maxillary right first molar (defined as constant site, CS) and a site with the greatest probing depth (defined as deepest site, DS). Microbial samples were analyzed by culture techniques. No significant differences in clinical parameters were found between diabetics and healthy siblings at any examination. The SBI in the non-diabetic group at T2 and at T3 was significantly lower than at baseline. PD and AL of constant sites in the diabetic group at T3 were significantly higher than baseline. There was a significant increase in Prevotella intermedia at T3 as compared with baseline for deepest sites in the diabetic group. Cluster analysis revealed, in a former study, two clusters (IV and V) at baseline which were significantly different from the overall mean regarding composition of Porphyromonas gingivalis and Capnocytophaga spp. They were not significantly different for periodontal parameters from TO to T3. These data would suggest no significant differences in clinical parameters between the diabetics and non-diabetic siblings throughout this 3-year longitudinal study.

Actinobacillus Infections↗
PubMed1997

Craniomandibular disorders and orthodontic treatment need in children.

Two hundred and forty subjects (113 boys and 127 girls), divided in three age groups, 7, 11, and 16 years were interviewed and clinically examined to estimate the prevalence of CMDs and the need for functional treatment, and to compare the functional status of the stomatognatic system in two subgroups: those judged to need orthodontic treatment and those judged not to need orthodontic treatment. Signs and symptoms of craniomandibular disorders were quite common and, in most cases, mild. There were significant differences in prevalence of CMDs between sexes. Only 3.7% of the patients were judged to need some functional treatment for CMDs. Trauma to the facial area and headaches were significantly associated with signs and symptoms of CMDs. No indication was found that oral parafunctions produce CMDs. No greater prevalence of CMDs signs and symptoms was found in subjects who needed orthodontic treatment than in subjects who did not need orthodontic treatment. In conclusion, preliminary results of this ongoing study support the contention that the high prevalence of signs and symptoms of CMDs is not really a measure of masticatory dysfunction, and that malocclusion does not appear to cause CMDs and/or to increase craniomandibular treatment need in a young population.

Adolescent↗
PubMed1995

Antimicrobial susceptibility of periodontopathic bacteria associated with failing implants.

The aim of this study was to examine the subgingival microflora associated with failing implants, and to determine their susceptibility to commonly used antibiotics in periodontal therapy and dental practice. Thirteen partially edentulous patients with 19 failing implants were selected. Clinical examination included probing depth, attachment level, gingival index, plaque index, and radiographic analyses. Two subgingival plaque samples were taken from each failing implant and analyzed for microbial composition. Fusobacterium nucleatum, Porphyromonas gingivalis, and Prevotella intermedia were the prevalent cultivable microflora. Antimicrobial susceptibility of isolates was determined by the agar dilution technique. Antibacterial activity of penicillin G, amoxicillin, amoxicillin-clavulanate, and the combination amoxicillin-metronidazole was significantly higher than with other antibiotics tested. These data indicated that the commonly-used antibiotics were highly effective against bacteria isolated around failing implants, which would suggest the use of these antibiotics to control peri-implant infections.

Amoxicillin↗
PubMed1995

Periodontal status and selected cultivable anaerobic microflora of insulin-dependent juvenile diabetics.

The periodontal status and subgingival microflora of insulin-dependent juvenile diabetic (JD) patients (n = 16, mean age = 11.3) were compared with that of their non-diabetic cohabiting healthy siblings (HS, n = 16, mean age = 13.2). JD patients were monitored every 3 months for levels of glycosylated hemoglobin (HbA1c) and clinical and microbial parameters were measured 6 weeks before drawing blood for levels of HbA1c (M% = 8.76). Clinical indices, measured for the entire permanent dentition, included: probing depth (PD), attachment level (AL), sulcus bleeding index (SBI), and plaque index (PI). Subgingival plaque samples were obtained at 2 sites from each subject; whenever possible, the site with the deepest probing depth and the mesial aspect of the maxillary right first molar were used. Microbial analyses were determined by cultural characteristics and biochemical tests. No significant differences were detected in any of the clinical indices for the entire dentition. The mean AL for JD sites was 2.32 +/- 0.83 mm and for HS sites was 2.2 +/- 0.85 mm. Mean percentage of total cultivable anaerobic microflora included Capnocytophaga spp. (JD, 13.21%; HS, 11%) and Porphyromonas gingivalis (JD, 5.1%; HS, 7.9%). Differences between the two groups were not statistically significant. When cluster analysis was performed on sampled sites, one cluster group in JD patients showed significantly elevated P. gingivalis and lower Capnocytophaga spp. levels as compared to the overall mean. The clinical parameters of this cluster were characterized by statistically significant greater loss of attachment and probing depth. These data would suggest few differences between JD patients and their HS in this population.

Adolescent↗
PubMed1994

[Periodontal regeneration: the use of polypeptide growth factors].

Polypeptide growth factors are a class of potent natural biologic mediators which regulate many of the activities of wound healing including cell proliferation, migration and metabolism. Periodontal regeneration is thought to require the migration and proliferation of periodontal ligament cells on the root surface. In fact, repopulation of the detached root surface by cells from periodontal ligament (PDL) is a prerequisite for new attachment formation. Many studies suggested that Polypeptide Growth Factors (PGF) such as Insulin-like Growth Factor I (IGF-I), Platelet Derived Growth Factor (PDGF), Transforming Growth Factor B (TGF-B), Epidermal Growth Factor (EGF), are important mediators of cellular events in wound healing. Studies in vitro analysed the mitogenic effects determined on periodontal ligament cells by growth factors using (3H) Thymidine incorporation during DNA synthesis. The results suggested that recombinant human PDGF and IGF-I stimulate the proliferation of PDL fibroblastic cells and the combination of these growth factors showed a synergistic effect revealing the highest mitogenic effect among all individual growth factors as well as any combination of the growth factors tested. Furthermore these studies demonstrated that rh-PDGF and IGF-I stimulate chemotaxis of PDL fibroblastic cells, and supported a role for TGF-B as a regulator of the mitogenic response to PDGF in these cells. Other studies in vivo showed periodontal tissues regeneration introducing mixtures of recombinant human platelet derived growth factor and insulin-like growth factor into lesions of experimentally induced periodontitis in beagle dogs and monkeys.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[The therapy of anterior disk dislocation in craniomandibular disorders. A clinical case report].

The authors discuss the outcomes of therapy for CMDs and present a clinical case reporting an alternative method for the treatment of disc displacement. The orthopaedic therapy for CMDs is based on the use of interocclusal splints. Two kind of splints are prescribed to patients with CMDs: stabilization or repositioning splint. The former is used for a conservative treatment, the latter for irreversible treatment. In view of the poor long-term success of repositioning therapy, the cost of subsequent dental treatment, and the great potential for iatrogenic occlusal and muscular problems, the authors believe that the initial treatment approaches should be, in any case, conservative, reversible, and non invasive. The authors prescribe to their patients the repositioning splint for use either part-time or full time use. Part-time use is effective for preventing disc displacement without reduction. If used full time, once joint noises, pain, and displacement are decreased, the appliance should be adjusted to/or replaced with a stabilization appliance to allow posterior positioning of the mandible into a more physiologically stable position. The authors present a clinical case, a 27 yo female with disc displacement with reduction was treated with stabilization splint. After 6 weeks of therapy she returned reporting a temporary closed lock and sharp pain in the left TMJ. An anterior repositioning splint was fabricated in order to position the mandible forward. After 10 weeks of this treatment the patient reported absence of joint/muscle symptoms and of joint noise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Guided regeneration of the periodontal tissues with resorbable and nonresorbale membranes. I. Clinical evaluation].

The present experimental study has been undertaken in order to analyse clinically, in humans, the regeneration of periodontal tissue following two different surgical techniques of guided tissue regeneration therapy using a resorbable and a nonresorbable membrane. Clinical results have demonstrated no statistically significant difference between the techniques employed, both of the showing a favourable outcome if perfect plaque control in the postoperative period is performed.

Absorption↗
PubMed1991

[Guided regeneration of the periodontal tissues with resorbable and nonresorbable membranes. II. Microbiological evaluation].

The present experimental study has been undertaken in order to analyze the influence of bacterial recolonization on periodontal wound healing following guided tissue regeneration therapy in humans. Two different surgical techniques has been carried out: one using a non absorbable membrane and the other a absorbable one. Microbiological data indicate no statistically significant difference between the techniques employed. Furthermore our data have confirmed the necessity of maintaining the healing sites free from the main periodontal pathogens.

Absorption↗