A split-mouth study on microbiological profile in clinical healthy teeth and implants related to key inflammatory mediators.

This split-mouth study investigated the correlation of the qualitative and quantitative bacterial composition in dental plaque around clinically healthy periodontal and peri-implant subgingival sites with the levels of selected pro- and anti-inflammatory cytokines and the inflammatory infiltrate in the soft tissue surrounding a healthy dental implant and natural tooth in the same patient. Nine patients, all in good health and non-smokers, were studied. All of the patients were highly motivated in terms of oral hygiene and had healthy natural teeth and at least one healthy implant. After three sessions of professional oral care, clinical parameters were recorded. A sample of subgingival plaque was harvested with a sterile curette from the buccal side of the selected implants and teeth. The plaque samples were cultured to quantify the total microbiota and the number of obligate and facultative bacterial strains. Simultaneously, from the lingual/palatal aspect of the same implants and teeth the keratinized periodontal and peri-implant soft tissues were biopsied for cytokine expression and histomorphometric analysis. The tissue biopsies were halved: the real-time reverse transcriptase-polymerase chain reaction (PCR) was performed to detect active TNF-alpha, IL-1beta, IL-8, and TGF-beta2 and distribution, composition, quantification of inflammation were assessed in parallel. The patients harbored no periodontopathogens and the microbiological composition of the plaque taken from implant sites did not differ from that harvested from teeth. No significant differences were seen between implants and teeth for both proand anti-inflammatory cytokines. Even the histological examination showed no significant epithelial changes, although slight perivascular lymphocytic infiltration was seen in some biopsies.

Cytokine, Chemokine, and Growth Factor Profile Characterization of Undifferentiated and Osteoinduced Human Adipose-Derived Stem Cells.

Bone is the second most manipulated tissue after blood. Adipose-derived stem cells (ASCs) may become a convenient source of MSC for bone regenerative protocols. Surprisingly, little is known about the most significant biomolecules these cells produce and release after being osteoinduced. Therefore, the present study aimed at dosing 13 candidates chosen among the most representative cytokines, chemokines, and growth factors within the conditioned media of osteodifferentiated and undifferentiated ASCs. Two acknowledged osteoblastic cell models, that is, MG-63 and SaOs-2 cells, were compared. Notably, IL-6, IL-8, MCP-1, and VEGF were highly produced and detectable in ASCs. In addition, while IL-6 and IL-8 seemed to be significantly induced by the osteogenic medium, no such effect was seen for MCP-1 and VEGF. Overall SaOS-2 had a poor expression profile, which may be consistent with the more differentiated phenotype of SaOs-2 compared to ASCs and MG-63. Instead, in maintaining medium, MG-63 displayed a very rich production of IL-12, MCP-1, IP-10, and VEGF, which were significantly reduced in osteogenic conditions, with the only exception of MCP-1. The high expression of MCP-1 and VEGF, even after the osteogenic commitment, may support the usage of ASCs in bone regenerative protocols by recruiting both osteoblasts and osteoclasts of the host.

Transforming growth factor-beta and interleukin 10 in oral implant sites in humans.

Cross-talk between cells and cytokines in peri-implant tissue is largely unknown. The immune response in the gingival mucosa appears to favor implant integration over rejection, since titanium-implant-retained overdentures show long-term success. This study evaluates pro-inflammatory (interleukin [IL]-2, interferon [IFN]-gamma, IL-12) and anti-inflammatory (IL-4, IL-10, transforming growth factor [TGF]-beta1) cytokine mRNA expression and tissue morphometry in peri-implant soft tissue from patients before and during treatment with Brånemark titanium implants. Immediately after treatment with endosseous implant and overdenture, TGF-beta1 mRNA increased in peri-implant mucosa specimens; transcript accumulation for IL-10 was elevated at 4 months and decreased dramatically thereafter. Transcripts for IL-2, IFN-gamma, IL-12, and IL-4 were absent. Healthy osseointegrated implants showed no histological inflammation in most patients. These findings suggest that newly classified TGF-beta and/or IL-10 secreting T regulatory (r)/T helper (h)-3 cells may populate implant insertion sites.

Cytokine production and bone remodeling in patients wearing overdentures on oral implants.

The stability of titanium dental implants is determined by osseointegration. Bone is a dynamic tissue continuously remodeled through resorption and formation, processes controlled by local cytokine production. This study investigated osseotropic cytokine expression in gingival mucosa, in the intraforamina and inferior first molar zones, during rehabilitation with implant-retained overdentures. Specimens were taken from six patients prior to placement of implants in the intraforamina bone; at connection of healing abutments; and 4, 8, and 12 months after prosthetic anchorage. Through semi-quantitative reverse-transcriptase polymerase chain-reaction, the following constitutively expressed cytokines were found at first surgical stage: interleukin-1, -6, and -8; small amounts of interleukin-11; stem cell factor; and transforming growth factor-beta1, -beta2, and -beta3. From the connection of healing abutments to 12 months after prosthetic anchorage, transforming growth factor-beta1, -beta2, and -beta3 were markedly higher than initial values. Expression of interleukin-6 and -8 decreased 8 months after prosthetic anchorage, while that of interleukin-1 increased at 12 months. In cultured gingival fibroblasts, modulation of cytokine secretion was also time-dependent. Cell culture supernatants influenced osteoclast-like multinucleated cell formation in long-term human marrow culture or osteoblast function, depending on the cytokine profile produced. These results are consistent with functional contributions of cytokines to osseointegration and minimization of posterior edentulous zone bone resorption.

In vitro effect of transforming growth factor-beta on adhesion molecule expression by human gingival fibroblasts cultured in the presence of a titanium abutment.

BACKGROUND: There is little information in the literature on the structural basis mediating gingival cell adhesion to the surface of titanium abutments. We cultured gingival fibroblasts on a titanium abutment creating as closely as possible the in vivo state. We analyzed the constitutive and transforming growth factor (TGF) beta-induced expression of the adhesion molecules CD44, CD49b, CD49c, CD51, CD54, and CD61 and extracellular matrix (ECM) components fibronectin, laminin and collagen IV. METHODS: Three totally edentulous patients underwent implant treatment to anchor the mandibular denture on 2 implants. Gingival mucosa cell specimens were collected from the mandible during the first surgical stage and the gingival fibroblast cultures were prepared. Cells were cultured for 48 hours with or without isoforms TGF-beta1, TGF-beta2, and TGF-beta3. The expression of adhesion molecules and ECM components was analyzed by immunofluorescence staining and flow cytometry. RESULTS: The addition of TGF-beta isoforms to the cell culture over the incubation period had little effect on cell growth rate, but significantly influenced cell orientation, which changed from a sun-burst pattern in control conditions to a more elongated organization and perpendicular to abutment surface. In all fibroblast preparations, a marked expression of CD44 and a moderate positivity for anti-CD49b and CD49c were found. By contrast, CD51, CD54, and CD61 expressions were negligible. When fibroblasts were cultured for 48 hours in the presence of TGF-beta, the expression of most of the receptor molecules increased. The cells expressed constitutively moderate levels of laminin and fibronectin and low amounts of collagen IV. By contrast, treatment with any one of the 3 TGF-beta isoforms greatly enhanced the expression levels of fibronectin, laminin, and, especially, collagen IV. CONCLUSIONS: TGF-beta not only seems to affect the orientation of the cultured gingival fibroblasts, but also to induce a clear-cut modification of their adhesion molecule expression.

Detection of platelet-activating factor in gingival tissue surrounding failed dental implants.

BACKGROUND: Dental implant therapy has entered routine clinical practice. However, the failure rate of implants at 5 years, due to biological factors, is still around 7%. The pathogenesis of implant loss involves a complex network of cells and inflammatory mediators. This study evaluated platelet-activating factor (PAF), a potent phospholipid mediator of inflammation, in soft tissue surrounding failed dental implants versus healthy implants. METHODS: PAF was estimated on extracted lipids by bioassay on washed rabbit platelets; inflammatory cell populations were assessed semiquantitatively after staining, and microvessel density was evaluated after immunohistochemical staining. RESULTS: Biologically active PAF was detected in the lipid extracts of samples excised from gingival tissue of patients with failed implants, but not in samples from patients with osseointegrated implants or from healthy edentulous subjects. The amount of PAF detected in failed implants was significantly higher than in healthy implants, suggesting a local production of this mediator. CONCLUSIONS: The presence of PAF was associated with histopathological findings of local inflammation and increased blood vessel density.

Innervation of the human temporomandibular joint capsule and disc as revealed by immunohistochemistry for neurospecific markers.

An immunohistochemical investigation for the neurospecific markers S-100 protein and protein gene product 9.5 was carried out on 12 healthy temporomandibular joint discs and capsules that were taken at autopsy from human adults. Large nerve trunks in the joint capsule and posterior disc ligament, as well as small nerve bundles and single nerves in almost all parts of the capsule, were heavily stained by anti-S-100 antiserum. The S-100 immunoreactive chondrocytes were also detected in the disc. Antiprotein gene product 9.5 similarly evidenced nerve fibers in the capsule and posterior disc ligament, and it also labeled a few small nerve bundles and a number of single fibers in the peripheral portions of the disc. No corpuscular or specialized endings were encountered in the specimens. These results give new support to the existence of a rich innervation of the human temporomandibular joint capsule and disc that should be further characterized with regard to type, function, and neuropeptide content.

Sinus floor augmentation with autogenous iliac bone block grafts: a histological and histomorphometrical report on the two-step surgical technique.

In thirteen patients, screw-type endosseous implants were inserted 6 months after sinus floor elevation and augmentation with autogenous iliac bone block grafts. Bone biopsies were harvested at graft positioning (baseline), at implant placement (6 month) and at abutment connection (1 year). Histological evaluation suggested a decrease in the volume of mineralized tissue and in the vitality of the grafts 6 months after graft insertion, followed by an increase at abutment connection. Histomorphometric analysis of the bone specimens showed that, at implant placement, bone content was reduced by 5.2% on average, while 12 months after grafting it had increased by 4.8% compared to the amount of mineralized tissue contained in the graft at baseline. The results suggest that in sinus floor augmentation procedures with autogenous iliac bone blocks, a two-step surgical technique allows implant insertion when graft healing is entering a phase of greater density and vitality.

[Preliminary study of the behavior of the rest position and the minimum phonetic distance in edentulous patients rehabilitated with prostheses with modification of the palatal thickness]. / Studio preliminare sul comportamento della rest position e della distanza fonetica minima in pazienti edentuli riabilitati protesicamente in cui veniva modificato lo spessore del palato.

BACKGROUND: Various clinical parameters, as well aesthetics, must be taken into account in determining the vertical dimension of occlusion (VDO) when rehabilitating edentulous subjects. These include the freeway space (FS), the physiological rest position (PRP) and the minimum speaking space (MSS). METHODS: Eight edentulous patients were rehabilitated firstly with complete denture; FS and MSS were monitored using a non-invasive computerized system, and increasing the thickness of the denture palate vault. RESULTS: FS and MSS do not appear to be correlated; MSS appears to be more reliable parameter than FS, as it is not influenced by the patient's will. CONCLUSIONS: Increasing the thickness of the palate vault causes a marked lowering of the mandible during speech, in agreement with Clemencon.

[Psychometric and psychofunctional studies of a group of patients with craniomandibular disorders]. / Studio psicometrico e psicofunzionale di un gruppo di pazienti con disturbi craniomandibolari.

The base myoelectric of masticatory muscles, and their response to stressor, was studied in a group of patients affected with craniomandibular disorders (CMD) and in a control group. Patients suffering from craniomandibular disorders were affected by at least two of these three groups of symptoms: 1) articular and/or muscular pain; 2) articular noise; 3) alteration of mandibular mobility. The psychofunctional investigation was as follows: in order to measure the base myoelectric activity of the masticatory muscles and their response to stress, the Myotron 222 two-channel electromyographs were used, so as to record the activity of four muscles contemporaneously. The research was conducted on the masseter and anterior fascia of the temporal muscles, which are the most readily accessible of the elevator muscles. A non-specific stressor (shot pistol) was administered to the subjects after the base myoelectric level had been established. These factors were evaluated on the electromyograms: base activity before the stressor; the shape of the response to the stressor; the recovery time after the stressor. The minimum activity before the stressor was usually measured as the minimum activity the subject was able to maintain for roughly one minute. The psychometric investigation used "Minnesota Multiphasic Personality Inventory" (MMPI); this is a nonprojective personality test widely used in clinical psychology. The base level of myoelectric activity was higher in patients affected with craniomandibular disorders than in healthy patients, who generally had low initial values.(ABSTRACT TRUNCATED AT 250 WORDS)

[Polyamines in tumors of the oral cavity]. / Le poliamine nei tumori del cavo orale.

The polyamines putrescine, spermidine and spermine are essential for normal growth and differentiation and the activity of the enzymes participating in their synthesis and catabolism are markedly modified in actively proliferating cells in vitro and in vivo. In some neoplastic cells a good correlation is observed between polyamine concentration and histology, so that a potential usefulness as diagnostic and prognostic markers has been suggested. In the study of ornithine decarboxylase, S-adenosylmethionine decarboxylase and spermidine acetyltransferase activities and of polyamine concentration in tumors of the oral cavity we have shown a marked increase in the tumor cells. In the epulis the ratio spermidine/spermine is inverted, so that it could be useful in differentiating benign from malign tumors.

[Impression method in patients with maxillo-facial loss with reduction of the degree of oral opening]. / Metodo d'impronta in pazienti maxillo-facciali con riduzione del grado di apertura orale.

The article describes a method for obtaining an impression in patients suffering from a loss of maxillo-facial structure with reduced oral aperture. This involves making an individual resin tray, which is then divided in two, with four plugs on the underside for precise re-alignment later. The method suggested facilitates the insertion and removal of the tray. Thus an accurate impression of the perimeter can be obtained without the risk of trauma.

Bond between gold alloy and ceramic in relation to the thickness of the oxide layer.

BACKGROUND: The chemical bonding between metal and ceramic is aided by non-precious metal atoms and their oxides present on the metal surface. Aim of the study was to correlate metal-ceramic bonding with thickness oxide layer on a new gold alloy. METHODS: Thirty-two specimens were constructed in gold alloy and ceramic, with the aim of evaluating the degree (using shear test) and quality (using optical microscope) of bonding resistance between these materials, in relation to the thicknesses of the oxide layer produced on the metallic parts by means of different thermal procedures. RESULTS: Bond strength was practically the same with different thicknesses of the oxide layer. A slight reduction in the degree of bonding was observed in the non-oxidised models. CONCLUSIONS: For the gold-alloy here tested, the oxide layer seems to be not influent in the chemical metal-ceramic bond strength.

Healing properties of implants inserted concomitantly with anorganic bovine bone. A histomorphometric human study.

BACKGROUND: The present prospective, randomized, double-blind study evaluated the bone-forming process around implants inserted simultaneously with anorganic bovine bone (ABB) in sinus grafting. METHODS: A total of 18 threaded mini-implants with Osseotite (O) and Nanotite (N) surfaces were placed in seven patients (nine sites). After 12 months, the implants were retrieved and processed for histological analysis. A total of 18 cutting and grinding sections were investigated with bright-field light microscopy, circularly polarized light microscopy (CPLM), confocal scanning laser microscope (CSLM), and scanning electron microscope (SEM) with energy dispersive spectrometer (EDS). RESULTS: The bone-to-implant contact rate in native crestal bone was 62.6 ± 0.4% for N implants and 54.3 ± 0.5% for the O implants (p = 0.001). The collagen fibre density, as assessed by CPLM, was 79.8 ± 6.0 nm for the N group and 74.6 ± 4.6 nm for the O group (p < 0.05). Line scan EDS starting from ABB to newly formed bone showed a decrease in calcium content and an increase of carbon while phosphorus content was constant. CONCLUSIONS: While the N surface improved the peri-implant endosseous healing properties in the native bone, when compared to the O surface, it did not improve the healing properties in the bone-graft area.

Evaluation of occlusal contacts in the dental laboratory: influence of strip thickness and operator experience.

PURPOSE: The purpose of this study was to evaluate the influence of recording strip thickness and of operator-dependent factors on the assessment of contact area on a cast mounted on an articulator. MATERIALS AND METHODS: Thirteen dental students and 13 experts (dentists and dental technicians) performed occlusal maneuvers on casts mounted on an articulator, using recording strips of 8- and 40-micron thickness. Contact area, force, and time of biting relative to each group of operators using each type of paper were compared. RESULTS: Both groups obtained significantly greater contact areas with the thicker strip. Students applied significantly stronger but shorter bitings than experts, but obtained smaller contact areas, particularly with the thinner strip. In operators, the extension of contact markings using the 8-micron strip was closely related to the biting time but not to the occlusion force, while neither time nor force of biting had a significant influence when using the 40-micron strip. CONCLUSION: The assessment of occlusal contact in the dental laboratory was significantly influenced by paper thickness, operator experience, biting force, and time. The 40-micron strip was less influenced by operator experience, strength, and duration of biting.

Oral conditions and aptitude to receive implants in patients with removable partial denture: a cross-sectional study. Part II Aptitude.

The aim of this study was to evaluate the possibility of replacing removable partial denture (RPD) with fixed partial dentures on osseointegrated implants in a selective group of patients with partially edentulous lower jaws. Forty patients were evaluated to receive implants. Twenty-three patients showed a precarious oral hygiene, five patients refused the treatment (being satisfied with their RPD), six refused for economic reasons, three patients refused for fear and scepticism, one for long duration of therapy, and one was not treated because of a very marked atrophy of the alveolar crest. Finally, one patient was treated with implants. For these reasons, at the present time implants are not an appropriate treatment for introduction into large-scale public health programmes and RPD must still be considered a valid therapeutic procedure.

Evaluation of the utility of cephalometric parameters in constructing complete denture. Part II: placement of anterior teeth.

Various types of parameters, including cephalometric ones, have been used in the construction of complete denture. This study aimed to evaluate the utility of cephalometric parameters for this purpose. The position of the anterior teeth in a group of 42 edentulous patients, successfully rehabilitated with complete denture according to clinical parameters, was evaluated by cephalometrics following the Ricketts' design. Data obtained were then compared statistically with those reported by Ricketts for dentate subjects, the position of the maxillary incisors was slightly anterior.

The influence of selective grinding on the thickness discrimination threshold of patients wearing complete dentures.

The influence of selective grinding on the ability of patients wearing complete dentures to discriminate thicknesses occlusally was evaluated. The study included two groups of white Caucasian patients, matched for age, sex and duration of edentulism; 12 wearing traditional complete dentures and 12 wearing maxillary complete denture and mandibular implant-retained overdenture (MIR-OVD). The ability to discriminate thickness was evaluated before and after selective grinding. In both groups, sensitivity improved after selective grinding. Subjects wearing MIR-OVD showed a better ability to discriminate thickness than those rehabilitated with traditional complete dentures. The thickness discrimination threshold might be a suitable method to evaluate complete dentures fit.

Influence of the thickness of the resin palatal vault on the closest speaking space with complete dentures.

The closest speaking space (CSS) has been considered stable over time, and therefore useful to determine the vertical dimension of occlusion (VDO) in edentulous patients. Clemençon affirms that, in complete denture wearers, CSS is not constant but depends on the thickness of the resin palatal vault, and that is the air volume needed to pronounce words to remain constant. The aim of this study was to evaluate Clemençon hypothesis in a group of edentulous patients rehabilitated with traditional maxillary denture and mandibular implant anchored overdenture. The CSS was determined by means of a kinematics method using the Elite System(R) at 30, 60, 90, 180, 360 days from delivery. The CSS was assessed twice at each stage: with the unmodified denture and a second time after thickening the resin palatal vault by 2 mm with a calibrated wax layer. The CSS after thickening the resin palatal vault was wider. The wider CSS observed can be because of oro-sensory feedback excited by contact between tongue and palatal vault. As hypothesized by Clemençon thickening the resin palatal vault could be a useful procedure to increase the VDO, in cases in which it is too low from the aesthetic stand point.

Comparison of marginal fit of 3 different metal-ceramic systems: an in vitro study.

PURPOSE: The aim of this study was to compare the marginal adaptation of metal-ceramic crowns made with 3 different metal substructures. MATERIALS AND METHODS: Seventy-five gypsum dies were fabricated from a master steel die. They were randomly divided into 3 groups of 25 dies each. A metal coping was prepared on each die using a different technique for each group: composite alloy, electroforming, and cast high-noble alloy. Ceramic was baked on all of the samples following the same protocol and simulating the shape and size of a maxillary central incisor. All specimens were evaluated under a stereomicroscope at 200x magnification. The marginal gap was measured at 8 different points on each specimen before and after ceramic application and also on the master steel die. A total of 3,600 measurements was evaluated. The results were statistically elaborated by means of a t test and one-way analysis of variance (ANOVA). RESULTS: The ANOVA revealed a significant difference in mean marginal gap before and after ceramic application within each group. Electroforming (mean 32 microns) and high-noble alloy (mean 31 microns) showed better marginal fit after ceramic application and on the master steel die compared to composite alloy (mean 68 microns; P < 0.0001). CONCLUSION: Marginal gaps are influenced by the application of ceramic and by the alloy used for the substructure, and the values obtained were within the limits of clinical acceptability (70 microns).