Histological and clinical survey of polylactic-polyglycolic acid and dextrane copolymer in maxillary sinus lift: a pilot in vivo study.

Of various proposed alternatives to autogenous bone, a synthetic, degradable copolymer of PLA-GLA and dextrane seems to be a promising biomaterial for maxillary sinus lift. Consecutive partially edentulous patients showing severe monolateral posterior maxillary atrophy were treated via sinus lift using PLA-GLA-dextrane copolymer as the sole filler. Delayed implant positioning was performed and cores of regenerated tissues and native bone controls were retrieved and evaluated by light and electron microscopy, histomorphometry, microhardness and qualitative X-ray analysis. Seven sinuses in 7 patients were augmented with PLA-GLA-dextrane copolymer. Six to nine months after the copolymer 'graft', 17 bone cores were retrieved: all histological sections contained newly synthesized, mineralized material and new bone in various stages of development. Histomorphometry revealed average Trabecular Bone Volume (TBV) values ranging from 51% (6 months) to 77% (9 months). Backscattered scanning electron microscopy (BSE) in experimental and control samples confirmed histology findings. Microhardness values suggested newly formed bone at nine months was not as hard as native bone. Ca and P content was similar in 9-month regenerated and native bone. Seventeen implants were inserted in the second stage of surgery: resulting Implant Success (SR) and Cumulative Success (CSR) up to 3 years were 100% following Albrektssons criteria. Sinus lift augmentation using PLA-GLA-dextrane copolymer as the sole filler resulted in uneventful surgeries. New bone formation was evident histologically and its maturation was still in progress after 9 months. Successful, staged implant positioning was achieved in regenerated tissue.

Focus on periodontal disease and colorectal carcinoma.

Diagnosis of focal disease, the theory that the human oral microbial (HOM) could affect the onset and development of systemic diseases, was very popular in the past, but the lack of scientific evidence has led to the abandonment of this idea. Interestingly, increasing evidence over the past 3 or so decades suggests that HOM can indeed serve as a reservoir for systemic dissemination of pathogenic bacteria and their toxins in distant body sites, favouring the developments of malignant tumours. Malignant tumours are complex communities of oncogenically transformed cells with aberrant genomes, associated non-neoplastic cells including immune and stromal cells, and sometimes HOM, including bacteria and viruses. Recent data suggest that HOM and periodontal disease play an active role in the pathogenesis of colorectal cancer, in fact HOM has been found within the colorectal cancer microenvironment, and the composition of the HOM was different from that of adjacent non-neoplastic tissue. An association of fusobacterium nucleatum with the colonic mucosa of colorectal cancer has been proven. Several questions thus arise. Is periodontal disease a risk factor for colorectal carcinoma? Given the connectivity of the digestive tract, could fusubacterium nucleatum or other HOM be involved in additional gastrointestinal disorders? Furthermore, based on the "mobility" of Fusubacterium nucleatum and the omnipresence of cadherins, could this organism be involved in cancers beyond the gastrointestinal tract? Answers to these questions will shed new lights on the role of the HOM in onset of diseases.

Mastication induces long-term increases in blood perfusion of the trigeminal principal nucleus.

Understanding mechanisms for vessel tone regulation within the trigeminal nuclei is of great interest because some headache syndromes are due to dysregulation of such mechanisms. Previous experiments on animal models suggest that mastication may alter neuron metabolism and blood supply in these nuclei. To investigate this hypothesis in humans, arterial spin-labeling magnetic resonance imaging (MRI) was used to measure blood perfusion within the principal trigeminal nucleus (Vp) and in the dorsolateral-midbrain (DM, including the mesencephalic trigeminal nucleus) in healthy volunteers, before and immediately after a mastication exercise consisting of chewing a gum on one side of the mouth for 1 h at 1 bite/s. The side preference for masticating was evaluated with a chewing test and the volume of the masseter muscle was measured on T1-weighted MRI scans. The results demonstrated that the mastication exercise caused a perfusion increase within the Vp, but not in the DM. This change was correlated to the preference score for the side where the exercise took place. Moreover, the basal Vp perfusion was correlated to the masseter volume. These results indicate that the local vascular tone of the trigeminal nuclei can be constitutively altered by the chewing practice and by strong or sustained chewing.

Biologic evaluation of a silver-copper-germanium dental casting alloy and a gold-germanium coating alloy.

An Ag-Cu-Ge alloy and an Au-Ge alloy were evaluated for their hemolytic effect on rabbit blood, cytotoxicity to alpha-L fibrosarcoma cells, and allergenic effect on guinea pigs. Neither alloy evoked a significant hemolytic response; cytotoxicity, and that of pure germanium, was no greater than that of ZOE cement; and, on the basis of the guinea pig response, the potential human allergenic response was considered to be Grade I (weak) and Grade II (mild), respectively.

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.

Generalized juvenile periodontitis: report of a familial case followed for 5 years.

The case of a family, followed for 5 years and showing an exceptionally high prevalence of Generalized Juvenile Periodontitis (GJP), is presented. Two siblings were affected by a severe form of GJP meanwhile the dycorial twin of one was periodontally healthy. Both the affected siblings showed infection by Actinobacillus actinomycetemcomitans (Aa), but only one presented a reduced chemotaxis of the peripheral PMNs. The dycorial twin consistently displayed a freedom from Aa and a reduction in the peripheral PMNs chemotaxis. The extraction of the compromised teeth in the two affected siblings has been followed by colonization of new sites by Aa; only repeated administration of systemic tetracyclines seems to protect the subjects from colonization of other sites. These findings may contribute to the understanding of the etiology, pathogenesis, and therapy of juvenile periodontitis.

Recolonization of the subgingival microflora after scaling and root planing in human periodontitis.

The purpose of this study was to evaluate the recolonization patterns of the subgingival microflora of adult periodontitis patients after a single session of scaling and root planing. In each of eight patients, three clinically diseased sites were investigated microbiologically by darkfield microscopy and cultural analysis. After initial clinical and microbiological parameters were determined, each subject received a single session of scaling and root planing but no oral hygiene instructions. Clinical indices were measured and microbial parameters were reassessed 7, 21, and 60 days after treatment in a manner such that each of the test sites was sampled only once after treatment. Recolonization was evaluated by matching any single site with its own preoperative site. A significant improvement in probing depth was noted for up to 60 days after treatment, while the gingival index did not change markedly during the course of the study. The microbial composition of treated sites 7 days after scaling and root planing, as determined by both cultural and darkfield data, was similar to that of periodontally healthy sites. Differences between cultural and darkfield data became apparent at the 21 day sampling point. The darkfield data showed that the sites consisted of cocci with few spirochetes. Cultural data demonstrated that the majority of the cocci were anaerobic, namely Streptococcus intermedius, Veillonella parvula, and Peptostreptococcus micros. At 60 days, there was no significant variation in any of the parameters from pretreatment levels. The most prevalent anaerobic rods prior to and 60 days after therapy were Fusobacterium nucleatum, Bacteroides gingivalis, and B. intermedius.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

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.

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.

Marginal tissue reactions at osseointegrated titanium fixtures (I). A 3-year longitudinal prospective study.

16 consecutive totally edentulous patients were provided with 95 osseointegrated titanium fixtures in 7 upper and 9 lower jaws. Facultatively removable bridges were later connected to abutments, attached to the fixtures. The marginal soft and hard tissue reactions were investigated at a baseline examination and after 6, 12, 21, 30 and 39 months by standardized clinical and radiographical methods. At the last examination, microbiological samples and gingival biopsies were also analysed. The % ratios of abutments without plaque, 70-75%, and without any gingivitis, 80-85%, were almost constant throughout the study. The mean probing depth was 2.9 mm at the final examination. About 75% of all probing depths were 3 mm or less and none exceeded 5 mm. The bridge-gingiva distances increased during the investigation. Attached gingiva surrounded 65% of the buccal and lingual abutment surfaces. Only 0.9 mm marginal bone was lost as a mean during the first year and not more than 0.05 mm annually for the next 2 years. After 6 months, no significant changes in marginal bone levels occurred. The perifixtural bone gradually became more radiopaque, especially marginally in upper jaws, indicating a successive load-related remodelling. The microbiotia comprised coccoid cells and non-motile rods to 93% in 32 samples. Healthy tissues were present in 35% of the 14 soft tissue biopsies. In a further 29%, only a slight inflammation was observed. No constant correlations could be established for any of the investigation parameters used. It is concluded that the marginal soft tissue reactions were mild and not significant for a progressive periodontitis. Mobility tests of separate fixtures combined with quantitative and qualitative standardized radiological examinations of the surrounding bone appear to provide a truer comprehension of longitudinal events at osseointegrated implants than conventional clinical soft tissue observations. The prognosis for the osseointegrated implants appears excellent, especially with regard to the microbiotia, the small marginal bone height changes, and the radiological indications of remodelling in the perifixtural bone.

Marginal tissue reactions at osseointegrated titanium fixtures.

A longitudinal prospective and a cross-sectional retrospective study were undertaken in order to investigate the marginal tissue reactions at osseointegrated titanium fixtures and their abutments, supporting fixed bridges. Conventional clinical periodontal examination methods were combined with a serial-identical radiography. At the termination of the studies samples were taken for microbiological and histological analyses. Altogether the reactions at 220 fixtures in 40 jaws were explored. The clinical parameters were not found correlated with the other examination methods. Only 0.9 mm marginal bone was lost as a mean during the first year and then not more than 0.05-0.07 mm as a mean annually for the follow-up years. A stress-related remodelling of the perifixtural bone was observed radiographically. The microbiotia in the gingival pockets was dominated by cocci and non-motile rods (94%), indicating a favourable composition if similar findings had been observed at teeth. Half the number of the biopsies had no inflammatory infiltrates and a further third had the lowest inflammatory score in a 3-grade scale. The results indicate that the soft tissue surrounding the gingival part of osseointegrated fixtures remains remarkably healthy, which, in combination with the annual minor loss of marginal bone, is an indication of good long-term clinical prognosis.

[Biofilms of the oral cavity. Formation, development and involvement in the onset of diseases related to bacterial plaque increase]. / I biofilm del cavo orale. Formazione, sviluppo e implicazioni nell'insorgenza delle malattie correlate all'accumulo di placca batterica.

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.

[In vitro antibiotic sensitivity of several species of oral spirochetes]. / Antibiotico-sensibilità "in vitro" di alcune specie di spirochete orali.

Results of a series of "in vitro" antibiotic susceptibility tests on some strains of oral Treponema are presented. Different antimicrobial agents have shown different results and only tetracycline and erythromycin have shown consistent antibacterial properties. Surprisingly penicillin has allowed a latent "in vitro" growth of the tested Treponema. The Authors conclude that, according to the data presented, a revision of the current criteria of the antimicrobial therapy for the oral infections associated with the presence of species of Treponema is needed.

[Periodontal disease and occlusal trauma: a still debated controversy? A review of the literature]. / Malattia parodontale e trauma da occlusione: una controversia ancora aperta?

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.

[The therapy of anterior disk dislocation in craniomandibular disorders. A clinical case report]. / Terapia del dislocamento anteriore del disco nei disordini craniomandibolari. Presentazione di un caso clinico.

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)

[Bacterial virulence in the etiology of periodontal diseases]. / La virulenza batterica nella etiologia delle malattie parodontali.

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.

[Implants in partially edentulous patients with history of periodontal disease]. / Impianti in pazienti parzialmente edentuli con storia di malattia parodontale.

BACKGROUND: Microbiota associated with periodontal diseases were also associated with periimplant diseases. The purpose of this study was to determine the clinical status and composition of subgingival microbiota of implants and natural teeth in a group of partially edentulous patients with history of periodontal disease. METHODS: 38 partially edentulous patients with history of periodontal disease, treated with dental implants, were selected for this study. Patients selected for the study were in good health condition and did not take any antibiotics in the last six months. One year after second stage surgery a total of 72 implants and 38 teeth underwent clinical and microbiological examination. Clinical parameters were PD, PAL, PI and GI. Subgingival plaque samples were analyzed by dark-field microscopy and cultural analysis. RESULTS: Clinical parameters didn't show any significant differences between periodontal and periimplant tissues. Dark-field microscopic examination showed higher prevalence of rods and spirochetes around implants than around teeth. There were no differences detected by cultural examination in the subgingival microbiota at peri-implant and periodontal sites. CONCLUSIONS: Findings from this study showed no differences between implants and teeth in partially edentulous patients with history of periodontal disease one year after second stage surgery. Implants were colonized by microbiota similar to that observed around teeth and were well-maintained in patients with a history of periodontitis.

[Periodontal regeneration: the use of polypeptide growth factors]. / Rigenerazione parodontale: utilizzo dei fattori di crescita polipeptidici.

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)