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Biomedical subjects

Marco Ferrari

Publications and source records attributed to Marco Ferrari.

104 records · Page 6Linked to original sources
PubMed2002

Influence of microbrush on efficacy of bonding into root canals.

PURPOSE: Recently, several 'one-bottle' systems have been introduced for bonding into root canals. This study evaluated the influence of two brushes used as carriers of a primer-adhesive solution in the formation of resin tags, adhesive lateral branches and hybrid layer when used to bond fiber posts. MATERIALS AND METHODS: Twenty root canal treated teeth, extracted for periodontal reasons, were selected for this study. The samples were randomly divided into two groups of 10 samples each: Group 1: Microbrush + One Step + Dual Link resin cement; Group 2: One Step + Dual Link resin cement. The adhesive system and resin cement were used strictly following manufacturers' instructions. The priming-adhesive solution of the 'one-bottle' system was light-cured before placing the resin cement and the post. Twenty translucent fiber posts were used. Then, root samples were processed for SEM observation. RESULTS: The adhesive system showed resin dentin interdiffusion zone (RDIZ), resin tag and adhesive lateral branch formation. Microscopic examination of restored interfaces of Group 1 showed a higher % (P < 0.05) of RDIZ than those found in samples of Group 2. In Group 2 samples RDIZ morphology was well detectable and uniform in the first two thirds of root canals while in the apical third the RDIZ was not uniformly present while in Group 1 RDIZ was visible at the apical third too. No statistically significant differences were found among the two groups coronally and at the middle third, while the apical third of Group 1 showed significantly more resin tags than in Group 2. The characteristic reverse cone shape of resin tags was always noted in the coronal and middle third of the root canals of both groups and at the apical third of Group 1. In the apical third of Group 2 root canals, the resin tags showed a less uniform morphology and a shorter length than those found in the other observed thirds.

Dental Bonding↗
PubMed2002

Adhesion testing with the microtensile method: effects of dental substrate and adhesive system on bond strength measurements.

PURPOSE: To evaluate the bond strength of a self-etching primer (SE, Clearfil SE Bond) and a one-bottle adhesive system (EX, Excite) on enamel and dentin. MATERIALS AND METHODS: Twenty-eight sound human molars were used. The teeth were randomly divided into four groups (n = 7): SE applied to enamel (SE-E); SE applied to dentin (SE-D); EX applied to enamel (EX-E); EX applied to dentin (EX-D). A resin (Tetric Ceram) block of approximately 5 x 5 x 5 mm was built up on the tooth and cured for 40 s. After 24 h, samples were obtained by cutting along the x and y axis of the tooth. Stick-shaped samples of approximately 0.8 mm2 cross-sectional area were obtained. The sticks underwent microtensile testing. RESULTS: The tensile bond strength (MPa) values of the test groups were: SE-E, 38.9 (+/- 4.8); SE-D, 44.5 (+/- 7.7); EX-E, 45.8 (+/- 4.7); EX-D, 42.9 (+/- 7.1). These values were not statistically significantly different. CONCLUSION: The null hypothesis was accepted that there is no difference between the self-etching primer and the one-bottle adhesive tested here. In addition, the bonding conditions provided by either bonding material on enamel were not significantly more favorable than on dentin. The majority of the specimens failed adhesively under load.

Adhesiveness↗
PubMed2000

Evidence for a neuroimmunomodulatory and a hematopoietic role of the Luschka's coccygeal body(3).

OBJECTIVES: In humans the glomus coccygeus was described in 1860 by Luschka. It is present at the coccyx tip and corresponds to a complex anastomosis between the median sacral artery and vein, and it is innervated by sympathetic fibers. In rats and mice it has been located in the tail ventral face. Its function is not known. According to our previous work, which demonstrated that hematopoiesis is under a noradrenergic control and based on the presence of epithelioid cells and sympathetic innervation, we assumed that the coccygeal gland might influence hematopoiesis via neuroendocrine or neural mechanisms. Therefore, the present study was undertaken to analyze the effect of glomus coccygeus on hematopoiesis. MATERIAL AND METHODS: Peripheral blood leukocyte and platelet concentrations as well as body temperature (BT) and body weight (BW), and norepinephrine (NE), adrenaline (A) and dopamine (DA) content in bone marrow of Luschkaectomized (LCGx), Sham LCGx operated (ShLCGx) and normal mice (Co) were investigated. RESULTS: We found that in LCGx vs. ShLCGx and Co, platelets and neutrophils increased while lymphocytes decreased. The effect of LCGx was significant from day 0 until day 65. Total leukocytes, monocytes, granulocytes, eosinophils and BT did not show any variation. Moreover, 22 days after the operation the amount of NE, A and DA seemed to be decreased in LCGx vs. ShLCGx while the difference was less evident between ShLCGx vs. Co. CONCLUSIONS: This study suggests for the first time a possible hematopoietic function and an immunomodulatory activity of the "Luschka's body" or Coccygeal body by a modulation of the sympathetic nervous system.

Journal Article↗
PubMedDate not supplied

Spatial distribution of vastus lateralis blood flow and oxyhemoglobin saturation measured at the end of isometric quadriceps contraction by multichannel near-infrared spectroscopy.

Muscle blood flow (MBF) and muscle oxygen saturation (SmO(2)) were measured at eight locations (four proximal, four distal) over a 4 x 8 cm(2) area of the vastus lateralis at rest and immediately after isometric, maximal quadriceps contraction using multichannel, frequency-domain, near-infrared spectroscopy. A venous occlusion was applied 20 s before the end of the exercise, so that the venous-occlusion-induced increase in total hemoglobin was recorded without any delay after the end of the exercise. Therefore, we were able to investigate the relationship between the exercise-induced changes in vastus lateralis MBF and SmO(2). After exercise, MBF increased significantly at each measured location. Comparing the MBF values measured at the end of exercise in the proximal and distal regions, we observed that only one proximal region had a significantly higher MBF than the corresponding distal one. The maximum desaturation measured during exercise was positively correlated with the postexercise to pre-exercise MBF ratio in both the proximal (P=0.016) and distal (P=0.0065) regions. These data confirm that frequency-domain tissue oximeters are noninvasive, powerful tools to investigate the spatial and temporal features of muscle blood flow and oxygenation, with potential applications in areas of pathophysiology.

Adult↗
PubMedDate not supplied

Bilateral prefrontal cortex oxygenation responses to a verbal fluency task: a multichannel time-resolved near-infrared topography study.

The letter-fluency task-induced response over the prefrontal cortex is investigated bilaterally on eight subjects using a recently developed compact, eight-channel, time-resolved, near-IR system. The cross-subject mean values of prefrontal cortex oxygen saturation (SO2) were 68.8+/-3.2% (right) and 71.0+/-3.6% (left), and of total hemoglobin concentration (tHb) were 69.6+/-9.6 microM (right) and 69.5+/-9.9 microM (left). The typical cortical activation response to the cognitive task [characterized by an increase in oxyhemoglobin (O2Hb) with a concurrent decrease in deoxyhemoglobin (HHb)] at each measurement point is observed in only four subjects. In this subset, the amplitude of the O2Hb increase and HHb decrease is uniform over each prefrontal cortex area and comparable between the two hemispheres. These findings agree with previous studies using continuous wave functional near-IR spectroscopy and functional magnetic resonance imaging, therefore demonstrating the potential of a time-resolved spectroscopy approach. In addition, a significant increase in SO2 levels was observed in the right (1.1+/-0.5%) compared to left side of the prefrontal cortex (0.9+/-0.5%) (P=0.005). A different pattern of cortical activation (characterized by the lack of HHb decrease or even increased HHb) was observed in the remaining subjects.

Adult↗
PubMedDate not supplied

In vitro hydrolytic degradation of composite quartz fiber-post bonds created by hydrophilic silane couplings.

The hydrolytic stability of a pre-activated MPS silane (Monobond-S) and a 2-component 4-META/ gamma-MPTS silane (Porcelain Liner M) to H202-etched quartz fiber posts was investigated using a modeling approach. Composite build-ups around silanized posts were stored dry for 24 hours, stored in deionized water at 37 degrees C for 24 hours, 1 week, 1 month or they were thermocycled. Sectioned specimens were prepared for microtensile bond testing and SEM examination; 4-META/gamma-MPTS silane produced a rapid decline in bond strength after 1 week and 1 month of water storage and after thermocycling. This was not apparent in pre-activated MPS silane. SEM revealed debonding along the post-composite interfaces, which were coupled with 2-component silane. The use of a hydrophilic resin monomer (4-META) for on-demand hydrolysis of the gamma-MPTS silane expedited interfacial water sorption and hydrolytic degradation, which may be prevented with alternative coupling strategies.

Composite Resins↗
PubMedDate not supplied

Clinical evaluation of fiber-reinforced composite inlay FPDs.

PURPOSE: This clinical study evaluated the behavior of inlay fixed partial dentures (IFPD) with conventional and modified framework designs over a period of 12 to 48 months. MATERIALS AND METHODS: Forty-one glass fiber-reinforced composite IFPDs were made to replace one missing maxillary or mandibular tooth. The frameworks were made only with parallel fibers in 19 restorations (group 1) and built with parallel and woven fibers modifying the design of the pontic element in 22 IFPDs (group 2) according to the manufacturer's instructions. All restorations were evaluated by color match, marginal discoloration, secondary caries, surface texture, marginal adaptation, fracture, and postoperative sensitivity. RESULTS: Three partial adhesive-cohesive veneering composite fractures occurred in the pontic element in group 1 after 3, 4, and 8 months, respectively. One cohesive fracture occurred in an abutment in group 2 after 46 months. Group 1 showed a 16% fracture failure rate; group 2 showed a 5% failure rate. However, no statistical difference was detected between the groups. IFPDs received the highest score at the following rates: color match 71%, marginal discoloration 96%, secondary caries 99%, surface texture 88%, marginal adaptation 98%, fracture 90%, and postoperative sensitivity 100%. Statistical analysis indicated significant deterioration of color match from baseline to last recall. CONCLUSION: There were nonsignificantly fewer fractures of the veneering composite with the modified design of the framework than with the conventional design. Repair of the fractured veneer of IFPDs may lengthen the lifespan of the restorations, but it is advisable only for slight damage.

Adolescent↗
PubMedDate not supplied

Clinical behavior of translucent-fiber posts: a 2-year prospective study.

PURPOSE: This study prospectively evaluated the clinical performance of three types of translucent posts over a follow-up period of between 2 and 3 years. MATERIALS AND METHODS: Selected were 225 patients with one premolar in need of endodontic treatment, followed by restoration with a fiber post and porcelain crown. The sample was randomly divided into three groups of 75 patients each. The same type of post was used in all patients within a group: group 1 = Aesthetic Plus; group 2 = DT; and group 3 = FRC Postec. For bonding the post, a light-curing adhesive (One-Step) and a dual-curing resin cement (Duo-Link) were applied in group 1 and 2 roots, whereas self-curing materials (Excite DSC as adhesive and MultiLink as resin cement) were used in group 3. After 6, 12, and 24 months, patients were recalled, and a clinical and radiographic examination was performed. For some patients, 30-month follow-up data were also collected. RESULTS: Debonding of the post occurrred in eight cases (3.5%); in another six cases, a recurrence of the periapical lesion was reported. CONCLUSION: The statistical analysis did not reveal any significant difference in the survival rate of the tested posts, suggesting that all are equally and sufficiently reliable for clinical use.

Adolescent↗
PubMedDate not supplied

Evaluation of the bonding mechanism of an adhesive material to primary teeth.

PURPOSE: The aim of this study was to evaluate with scanning electron microscopy (SEM) the bonding mechanism of the one-bottle adhesive Prime&Bond NT (Dentsply, PBNT) to enamel and dentin of deciduous teeth, following different methods of substrate treatment. METHODS: Eighteen extracted posterior deciduous teeth were randomly divided into 6 groups (N=3). The experimental groups differed for substrate and method of substrate conditioning prior to bonding with PBNT. Group 1: 36% phosphoric acid (PA)/PBNT on dentin; group 2: PA/PBNT on enamel; group 3: non-rinsing conditioner (NRC) (Dentsply)/PBNT on dentin; group 4: NRC/PBNT on enamel; group 5: PBNT on dentin without any previous conditioning; group 6: PBNT on enamel without any previous conditioning. On all the specimens, following the application of the adhesive solution, Dyract AP was layered on top and light-cured. The bonded specimens were processed for SEM observations. RESULTS: When used in combination with 36% phosphoric acid, PBNT was able to form a hybrid layer with resin tags on both enamel and dentin. Following conditioning with NRC, a thinner hybrid layer with shorter resin tags was developed on dentin; on enamel an etching pattern was still detectable. When only PBNT was applied without any previous conditioning, on dentin neither hybrid layer nor resin tags were visible; no sign of micromechanical bonding could be seen on the untreated enamel. CONCLUSIONS: The bonding mechanism of the one-bottle adhesive Prime&Bond NT on enamel and dentin of deciduous teeth is effective only following substrate conditioning with 36% phosphoric acid or NRC.

Acid Etching, Dental↗
PubMedDate not supplied

Clinical evaluation of the use of fiber posts and direct resin restorations for endodontically treated teeth.

PURPOSE: Restoration of root-treated teeth is routinely performed in clinical practice with a choice of therapeutic options, considering many factors to provide optimal mechanical properties, esthetics, and longevity. The aim of the present work was to present a preliminary clinical report on the use of fiber posts and direct resin composites for restoring root-treated teeth. MATERIALS AND METHODS: Thirty-eight anterior and 62 posterior endodontically treated teeth were selected from 3 private prosthodontic offices. The protocol used included endodontic treatment, with translucent fiber posts (DT post) bonded to the post-space using a '1-bottle' adhesive (One-Step, Bisco) and a dual-cure resin cement (DuoLink, Bisco). Direct resin restorations were performed using a micro-hybrid resin composite (Gradia Direct, GC) and a layering technique. Both opaque dentin and enamel and translucent enamel shades were used. RESULTS: Patients were recalled after 6, 12, 24, and 30 months, and the restorations assessed according to predetermined clinical and radiographic criteria. These clinician-mediated evaluation methods confirmed the good clinical performance of the restorations. CONCLUSION: Restoration of endodontically treated teeth with fiber posts and direct resin composites is a treatment option, that in the short term conserves remaining tooth structure and results in good patient compliance.

Adolescent↗
PubMedDate not supplied

Evaluation of the adhesion of fiber posts to intraradicular dentin.

The interfacial strength and ultrastructure of a total-etch, self-etch and self-adhesive resin cement used to lute endodontic glass fiber posts (FRC Postec, Ivoclar-Vivadent) was assessed with the "thin-slice" push-out test and transmission electron microscopy (TEM). The tested adhesive cements were Variolink II (Ivoclar-Vivadent), Panavia 21 (Kuraray Co) and RelyX Unicem (3M ESPE). In each group, seven posted roots were used for push-out tests and two were processed for TEM observations. The interfacial strength achieved by Variolink II (10.18 +/- 2.89 MPa) was significantly higher than Panavia (5.04 +/- 2.81 MPa) and RelyX Unicem (5.01 +/- 2.63 MPa), which were comparable to each other. TEM micrographs of the interface between Variolink II and intraradicular dentin revealed that the smear layer was totally removed and an 8-10 micron thick hybrid layer was formed. In the other group specimens, the smear layer was not completely dissolved and smear plugs were retained. Gaps were present between the hybridized complex and the adhesive layer in the Panavia 21 specimens and between the smear layer and underlying root dentin in the RelyX Unicem specimens. Interfacial strengths and microscopic findings were in agreement and indicated that the bonding potential of the total-etch resin cement was greater. The acidic-resin monomers responsible for substrate conditioning in Panavia 21 and RelyX Unicem appeared unable to effectively remove the thick smear layer created on root dentin during post space preparation.

Analysis of Variance↗
PubMedDate not supplied

Marginal adaptation of 1 fiber-reinforced composite and 2 all-ceramic inlay fixed partial denture systems.

PURPOSE: The aim of this in vitro study was to evaluate the marginal adaptation and retention of inlay fixed partial dentures (IFPDs) made with 1 fiber-reinforced composite and 2 different ceramic materials using quantitative scanning electron microscope analysis after thermal cycling and mechanical loading, which simulated approximately 5 years of oral service. MATERIALS AND METHODS: Eighteen IFPDs made with fiber-reinforced composite (SR Adoro/Vectris), zirconium oxide-TZP (Cercon), and magnesia partially stabilized zirconia (DC-Leolux) covered with silica-based ceramics were tested in this study. The specimens were mechanically loaded in the vestibular cusp of the pontic element in a computer-controlled masticator with 1,200,000 half-sinusoid mechanical cycles of maximum 49 N each at a frequency of 1.7 Hz. A total of 3,000 thermocycles at 5 degrees C and 55 degrees C, 2 minutes each, were performed simultaneously. The marginal adaptation was analyzed at the interface of the luting composite and the abutment inlay/onlay (CI) and at the interface of the tooth and the luting composite (TC). RESULTS: The percentages of continuous margin at the CI interface were 94.6 +/- 3.1 and 88 +/- 6.7 for Adoro/Vectris, 92.9 +/- 5 and 85.7 +/- 6.1 for Cercon, and 96.2 +/- 2.1 and 82.2 +/- 9.8 for DC-Leolux, respectively, before and after loading. The percentages of continuous margin at the TC interface were 86.7 +/- 6.7 and 62.5 +/- 16.4 for Adoro/Vectris, 93.3 +/- 3.4 and 83.2 +/- 5.9 for Cercon, and 96.1 +/- 2.4 and 75.3 +/- 7 for DC-Leolux. Statistically significant differences were found after loading between the fiber-reinforced composite and the 2 ceramic systems at the TC interface. CONCLUSION: Within the limitations of this experimental study with regard to the sample size and contacting vectors, the results showed that flexibility of the framework may play an important role in the marginal adaptation of the IFPDs. More rigid materials may transfer less stress to the margins, thus promoting a more stable adhesion to the dental tissues.

Acid Etching, Dental↗
PubMedDate not supplied

Comparison of 2 bonding systems and survival of fiber-reinforced composite inlay fixed partial dentures.

PURPOSE: This pilot clinical trial evaluated the clinical behavior of 3-unit inlay fixed partial dentures (IFPDs) made of the glass-fiber composite system SR Adoro/Vectris and luted with 2 different bonding systems over an observation period of 2 years. MATERIALS AND METHODS: Thirty-nine glass-fiber-reinforced composite IFPDs were made to replace 1 missing maxillary or mandibular tooth. Nineteen IFPDs were randomly assigned to group A and luted with a 2-step bonding system (Excite DSC), while the other 20 IFPDs of group B were cemented with a 3-step adhesive (Syntac). Events such as partial or total debonding of the IFPDs, fracture of the framework, or veneer and fiber exposures were considered failures. Color match, marginal discoloration, secondary caries, marginal adaptation, postoperative sensitivity, and surface texture were evaluated according to the United States Public Health Service modified criteria. RESULTS: Two debondings and 2 fiber exposures occurred during the observation period. All failures occurred in group A. Some fatigue microcracks in the pontic area of the 2 detached IFPDs were observed under scanning electron microscopy. The postoperative sensitivity of group A was much higher than that of group B, and the abutments luted with Excite DCS showed postoperative sensitivity during the first month in 42.2% of cases. The sensitivity disappeared completely after 6 months. Statistical analysis indicated significant differences in postoperative sensitivity (P < .05) between the 2 groups. CONCLUSION: The IFPDs bonded with a 3-step adhesive demonstrated good clinical service in the short observation period. The microfractures of the layering material observed on the debonded IFPDs may suggest excessive flexibility of the fiber structures, which occurs if the framework is fabricated without observing the recommended dimensions.

Adolescent↗