Correlation between halitosis, oral health status and salivary ß-galactosidases and time spent in physical activities in children.

AIM: The aim of this work was to evaluate the oral health status in children and to correlate it with time spent in physical activity per week. MATERIALS AND METHODS: Fifty children (mean age 9±2 years) attending the first visit at the Paediatric Dental Unit of the University of Rome "Tor Vergata" have been included in the study. The parents of all patients were interviewed about the medical history of the children and specific data, in particular, the time spent in physical activity per week. A trained dentist examined the oral cavity of the patients and the following clinical parameters were recorded: number of deciduous and permanent teeth, caries (on deciduous and permanent teeth), presence of gingivitis (0=no; 1=yes), tongue coating score (from 0=none to 3= > 2/3 tongue dorsum surface covered)", oral infections (0=no; 1=yes), oral hygiene index (0=insufficient, 1=sufficient, 2=good), presence of at least one incongruous restoration (0=no, 1=yes), oral breathing (0=no; 1=yes), fissured tongue (0=no, 1=yes), presence of aftous ulcers, herpetic lesions or candidiasis (0=no, 1=yes), food stagnation (0=no; 1=yes). The level of salivary ?-galactosidases activity was measured spectrophotometrically. The subjects were classified into "Group 0": children who did not practice any sports beside physical education class; "Group 2": 2 hours per week; "Group 3": 3 hours; and "Group 4": 4 hours. STATISTICS: Statistical analysis was performed using SPSS for Windows version 21 (IBM SPSS Inc., Chicago, IL, USA). The Pearson's correlation coefficient (P) was used to evaluate the linear relationship between continuous variables, and the Spearman's correlation coefficient (S) was calculated for ordinal variables. Analysis of variance (ANOVA) and the Fischer's Least Significant Difference (LSD) test were used to compare the parameters analysed in the study. Data were analysed using linear regression and descriptive statistics. The significance threshold was set at 0.05. RESULTS: A more physically active lifestyle was significantly associated with a better oral hygiene and a reduced level of salivary ?-galactosidases, halitosis, gingivitis and tongue coating. Results of the organoleptic evaluation of halitosis performed by the parents and sport hours/week practiced have shown that Group 0 and 2 were characterised by statistically significant higher scores with respect to the other groups (Group 0 vs. Group 3, p=0.014; Group 2 vs. Group 3, p=0.030; Group 0 vs. Group 4, p=0.001; Group 2 vs. Group 4, p=0.002) (P= -0.458). The spectrophotometric quantification of salivary ?-galactosidases has shown that increasing the hours of sports, the enzyme activity significantly decreases (S= -0,330); similar levels were found with 0 and 2 hours of sports, but an important decrease has been recorded with both 3 (Group 0 vs. Group 3, p=0,011; Group 2 vs. Group 3, p=0,006) and 4 hours of sports practiced (Group 0 vs. Group 4, p=0,014; Group 2 vs. Group 4, p=0,008). The level of significance between children who did not practice sport and those who did for 3 and 4 hours a week was 0.005 (Group 0 vs. Group 3) and 0.0018 (Group 2 vs. Group 4) with respect to tongue coating scores (P= -0,511) and 0.012 for both groups with respect to gingivitis (Group 0 vs. Group 3; Group 0 vs. Group 4) (P=-0,427). CONCLUSION: Children who practiced sport showed a better oral hygiene level and lower halitosis, with respect to those who did not.

Gold nanoparticles as scaffolds for poor water soluble and difficult to vehiculate antiparkinson codrugs.

We report the facile and non-covalent preparation of gold nanoparticles (AuNPs) stabilized by an antiparkinson codrug based on lipoic acid (LA). The obtained AuNPs appear stable in both dimethyl sulfoxide and fetal bovine serum and able to load an amount of codrug double the weight of gold. These NPs were demonstrated to be safe and biocompatible towards primary human blood cells and human neuroblastoma cells, one of the most widely used cellular models to study dopaminergic neural cells, therefore are ideal drug carriers for difficult to solubilize molecules. Very interestingly, the codrug-stabilized AuNPs were shown to reduce the accumulation of reactive oxygen species in SH-SY5Y cells treated with LD and did not change total oxidant status levels in cultured human blood cells, thus confirming the antioxidant role of LA although bound to AuNPs. The characterization of AuNPs in terms of loading and stability paves the way for their use in biomedical and pharmacological applications.

Effect of pre-operatory low-level laser therapy on pain, swelling, and trismus associated with third-molar surgery.

BACKGROUND: The extraction of impacted third molars is commonly associated to pain, edema, trismus, limited jaw opening and movements. The aim of this retrospective study is to verify if pre-surgical low-level laser therapy (LLLT) associated with the extraction of impacted lower third molars could add benefits to the postoperative symptoms respect LLLT performed only after surgery. MATERIAL AND METHODS: Data from 45 patients subjected to a surgical extraction of lower third molars were pooled and divided into three groups. Patients that received only routine management were inserted in the control group. Group 1, were patients that received LLLT immediately after surgery and at 24 hours. In group 2 were included patients treated with LLLT immediately before the extraction and immediately after the end of the procedure. Data were analyzed using linear regression and descriptive statistics. RESULTS: Both laser-treated groups were characterized by minor events of post-surgery complications of pain, edema, trismus. The use of NSAIDs in the first 24 hours was significantly inferior in Group 2. CONCLUSIONS: Pre-surgical LLLT treatment seems to increase the analgesic effect of LLLT. However, trismus and edema were reduced in both laser treated groups, independently from the period of irradiation.

Does cyclic guanosine monophosphate induce autophagy in thyroid malignant carcinoma through down-regulation of cyclic guanosine monophosphate phosphodiesterase?

The aim of this study was to evaluate whether or not the expression of cGMP- phosphodiesterases (cGMP-PDE) varies in different thyroid pathologies and to elucidate the relationship between the expression of cGMP-PDE, cGMP, and autophagy. Fifty-four thyroid biopsy samples, excised to perform the biopsy, were split into two parts and randomly assigned: one part was microscopically examined and histological classified, and the other was frozen and analysed in order to evaluate the cGMP-PDE activity. Intracellular cGMP was also measured. A strong expression of intracellular cGMP and cGMP-PDE activity was observed in carcinoma in respect to controls and benign pathologies. The level of cGMP-PDE in papillary carcinoma without lymph node involvement (N-) was approximately four-fold higher compared to those with lymph node invasion (N±). On the contrary, the cGMP was one and a half times higher in N± than N-. Our results are promising, although further epigenetical studies are needed to confirm this association. A correlation between the cGMP-degrading activity and the severity of thyroid pathology has been shown. The decrease of cGMP-PDE and the increase of cGMP in N± papillar carcinoma could be an autophagic stimulus, a defence mechanism of the body, against the cancer that is expanding and invading other tissues and organs.

Effect of low energy light irradiation by light emitting diode on U937 cells.

Photobiomodulation (PBM) can induce a set of different biological modulators either in vitro or in vivo. Experimental evidence has highlighted the role of light effects on the mechanisms related to inflammation, apoptosis and autophagy. The goal of this project was the evaluation of PBM on U937, an established cell line of histiocytic lymphoma origin. Several aspects of modulation of proinflammatory pathways were analyzed and autophagic and proapoptotic mechanisms related to low laser light exposure of cells were studied. As a source of low energy light emission, we used an NIR-LED device, characterized by an 880 nm-wavelength as light source. Flow cytometry analysis was performed on supernatants of controls and treated U937 cells to detect inflammatory cytokine levels. In order to evaluate NF-kB and caspase3 expressions, Western blot analysis was performed according to standard procedures. In this report, we show the effect of PBM on a monocyte/macrophage established tumor cell line (U-937). We demonstrate that LED exposure, in the presence or absence of lipopolysaccharide (LPS), activates cell degranulation, increased expression of Interleukin-8 (IL-8) and modulation of beta galactosidase activity. Evidence shows that the well-known pro-inflammatory nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and the apoptotic marker (caspase3/cleaved-caspase3 ratio) are up-regulated in response to a proinflammatory biochemical pathway.

Alkaline phosphatase level in gingival crevicular fluid during treatment with Quad-Helix.

The aim of this work is to assess the level of the human alkaline phosphatase enzyme (ALP) during palatal expansion with Quad-Helix (QH) appliance. A total of twenty-two orthodontic patients characterized by contraction of the upper jaw, that needed application of a QH in order to treat their condition, were included in this study. Gingival crevicular fluid (GCF) was collected at four different times: before cementation (T0), after two weeks (T1), after four weeks (T2) and after one year (T3) from application of QH. In each patient maxillary first molars, right (UM-right) and left (UM-left), which were connected with bands to QH, were used for testing; first lower molars were used as Controls (LM-right, LM-left). Data show that ALP level in tension sites was proportional to the average increase of the inter-molar distance; on the contrary, the enzymatic level in compression sites was characterized by an inverse trend. The only exception to this phenomenon was recorded after one year (T3), when the increase of ALP level in both sites of tension and compression was ascribed to a mild inflammation due to bacterial plaque accumulation. The level of ALP in control sites was constant for the whole period of observation. The described ALP fluctuations in accordance with the inter-molar distance increment, shows that the main action of QH on bone remodelling was exerted during the fourth week (T2); for this reason, the monitoring of this enzyme could be used as a marker of effective function of the QH appliance.

Association between the organoleptic scores, oral condition and salivary ß-galactosidases in children affected by halitosis.

OBJECTIVES: The goal of this work is to evaluate the association between organoleptic scores, oral condition and salivary ß-galactosidases, to facilitate the differential diagnosis of halitosis in children. METHODS: Fifty systemically healthy children with a primary complaint of oral malodour were included in this cross-sectional study. The organoleptic evaluation was carried out by two judges, evaluating the intensity of malodour of the air exhaled 5 s through the mouth of the patients, at a distance of approximately 10 cm from their noses; the level of salivary ß-galactosidases was quantified spectrophotometrically after a chromatic reaction between a salivary sample of each patient and a specific chromatic substrate of the enzyme. Clinical conditions, such as visible plaque and gingival bleeding index, tongue coating score, localized food stagnation and other oral parameters, were evaluated by qualified dentists through an oral check-up. RESULTS: The ß-galactosidase level was significantly related to the organoleptic scores and clinical parameters, such as the tongue coating score and the visible plaque index. Stratifying results with respect to the different phase of the day at which parents complained halitosis in their children, statistical analysis showed that the organoleptic scores and the level of ß-galactosidases were significantly higher in children who suffered of halitosis during the whole day, A = 40%, with respect to those without this problem, N = 20% (P = 0.001 and P = 0.006, respectively). CONCLUSIONS: Certain oral parameters such as halitosis during the whole day, high tongue coating score and high visible plaque index were particularly associated with an increase in the salivary ß-galactosidase level.

Prostaglandin E2 to diagnose between reversible and irreversible pulpitis.

The aim of this work is to verify a correlation between the grade of inflammation and the concentration of PGE2 in human dental pulp. A total of 25 human dental pulps were examined by histological analysis and radioimmunologic dosage of PGE2. The pulps used in this experiment were from healthy and symptomatic teeth; the first ones were collected from teeth destined to be extracted for orthodontic reasons. An increase was observed of PGE2 in reversible pulpitis compared with healthy pulps and with the irreversible pulpitis and the clear decrease of these when NSAIDs are taken. This study demonstrates that PGE2 level is correlated to histological analysis thus allowing to distinguish symptomatic teeth in reversible and irreversible pulpitis.

Thermal analysis of laser-softened gutta-percha.

The aim of this work is to examine the behaviour of laser treated gutta-percha (a–b) after heating, to test the validity of a new obturation technique. Samples of laser- and no laser- treated gutta-percha have been examined by the thermal/thermogravimetric analysis and compared. All samples have been submitted to four runs of heating from the temperature of 25–130 C, followed by spontaneous cooling. It was found that some samples have shown the typical behaviour of the alpha-gutta-percha; others have shown characteristics similar to the conventional beta-gutta-percha. The laser treated gutta-percha has shown a significant mass loss after the first run of heating, while the mass tends to stabilize after the third run. It has been demonstrated that the 980 nm diode laser used with cited parameters does not alters thermal behaviour of gutta-percha cones.

Micromorphometrical and histological analyses using two different oscillating osteotomy techniques compared with conventional rotary osteotomy.

The recently introduced ultrasonic osteotome procedure is an alternative to conventional rotatory burs. The aim of this study was to establish the differences between two ultrasonic osteotomes and conventional rotatory burs, in order to perform micromorphological and histological analyses of osteotomized bone surfaces. Bony samples were taken from adult bovine ribs including both the cortical and marrow bone. Soft tissues have been removed and the bone pieces were divided into four groups, to test four devices: a conventional osteotomy round bur, a Lindeman bur and piezoelectric osteotomes ES007 and the T-Black. Each device performed cuts that were examined via scanning electron microscope (SEM) and light microscopy (LM) to check respectively cut precision and bone architecture all along the defect borders. SEM analysis of specimens showed that burs created defects of greater width and with irregular edges while those produced by ultrasonic osteotomes were narrow and had mostly smooth cutting surfaces. The edges of incisions made by drills were full of bone fragments while less bone chips were observed on piezoincision’s ones. Dimensions of fragments were wider if cuts were made by burs too. LM analysis of samples showed focally, delicate bony trabecules crushed and pressed into the bone marrow in cutting made by burs. Samples cut by ultrasonic devices showed small or no smear layer and only partial or no crushed trabecules. Osteocytes seemed to be intact all along the cutting surface in all samples observed. In the present study, according to literature, ultrasonic surgery validity is confirmed. As a matter of fact, the greater the number of bone chips products, the greater the magnitude of the inflammatory process induced, as well as the possibility of a greater bone loss and delay in wound healing near the osteotomized area.

Bevacizumab-related osteneocrosis of the jaw.

We describe a case of jaw bone necrosis after a lung adenocarcinoma bone metastasis, treated the first time in 2004 by means of pneumonectomy and lymph node ablation. One week after a dental extraction, the patient experienced pain in the mandibular region, in conjunction with alveolar bone exposure. Treatment with amoxicillin and clavulanate every 12 hours for 15 days and 0.2% chlorhexidine rinses was administered and there was a remission of infective complications, but not the closure of the exposed alveolar bone. Only at this time did the patient refer that he was treated with bevacizumab therapy immediately after the extraction. A preventive dental assessment of patients scheduled for bevacizumab therapy should be useful as for the zoledronic acid therapy. Dental surgery procedures for patients during bevacizumab therapy should be carefully evaluated and considered as the last choice, to reduce all possible risks and prevent complications.

Microbiological and biochemical effectiveness of an antiseptic gel on the bacterial contamination of the inner space of dental implants: a 3-month human longitudinal study.

Microbial penetration inside the implants internal cavity produces a bacterial reservoir that is associated with an area of inflamed connective tissue facing the fixture-abutment junction. The aim of this clinical trial is to evaluate the effectiveness of a 1 percent chlorhexidine gel on the internal bacterial contamination of implants with screw-retained abutments and on the level of AST secreted in peri-implant crevicular fluid. Twenty-five patients (aged 29 to 58 years) each received one implant. Three months after the end of the restorative treatment, and immediately after a clinical and radiographic examination and the abutment removal, microbiological samples were obtained from the internal part of each fixture and biochemical samples were collected by peri-implant sulci. The patients were then divided into two groups: the control (CG; n=10) and test (TG; n=15) groups. The CG had the abutment screwed into place and the crown cemented without any further intervention. In contrast, before the abutment placement and screw tightening, the TG had the internal part of the fixture filled with a 1 percent chlorhexidine gel. Three months later, the same clinical, microbiological and biochemical procedures were repeated in both groups. Total bacterial count, specific pathogens and AST activity were detected. The clinical parameters remained stable throughout the study. From baseline to the 3-month examination, the total bacterial counts underwent a significant reduction only in the TG. In contrast, the AST activity showed a significant increase in the CG. The administration of a 1% chlorhexidine gel appears to be an effective method for the reduction of bacterial colonization of the implant cavity and for safeguarding the health status of peri-implant tissue over a 3-month administration period.

The correlation between different techniques for the evaluation of oral malodour in children with and without orthodontic treatment.

AIM: The aim of this work was to evaluate the correlation between different methods (organoleptic evaluation, gas chromatography, salivary ?-galactosidases activity) for the evaluation of halitosis in children. The secondary purpose was to investigate the influence of orthodontic treatment on halitosis. MATERIALS AND METHODS: Study Design: Oral malodour was detected with different methods in 50 children in the Paediatric Dentistry Unit, University of Rome Tor Vergata, Rome, Italy. During the dental visit, level of oral hygiene, tongue coating scores and presence of an orthodontic device, fixed or mobile, were recorded. Two trained and calibrated operators performed the organoleptic evaluation; the Oral ChromaTM device was used for the volatile sulfur compounds (VSCs) quantification and salivary ?-galactosidases (S?-g) activity was evaluated through the spectrophotometric method. STATISTICS: The Cohen's Kappa score was used to evaluate the level of agreement between the operators. The Pearson's correlation coefficient was used to evaluate the linear relationship between continuous variables (e.g. S?-g vs. VSCs values) and the Spearman's correlation coefficient was calculated for ordinal variables (e.g. organoleptic scores) vs. other parameters. The LSD test was used to compare the parameters analysed in the study. RESULTS: A positive and significant correlation between the organoleptic evaluation, the S?-g, the levels of hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) was found. The Spearman's correlation has shown that organoleptic scores were significantly correlated with S?-g (0.664, p<0.001) and the Oral ChromaTM measurements of H2S (0.538, p<0.001) and Ch3SH (0.316, p=0.026). The Pearson's correlation showed that S?-g was statistically significantly correlated with the Oral ChromaTM measurements of H2S (0.379 p=0.007) and Ch3SH (0.299, p=0.0035). Stratifying results for orthodontic treatment, it was possible to show that children under orthodontic treatment, both fixed or removable, were characterised by higher level of S?-g. The organoleptic evaluation and Oral ChromaTM measurements showed that children wearing fixed orthodontic were characterised by higher scores. CONCLUSIONS: There was a significant correlation between the three different techniques for the evaluation of oral malodour in children. Like in the adult population, the increase of S?-g activity was associated with oral malodour. The presence of fixed orthodontic appliances was correlated to increased scores of all methods for the evaluation of halitosis.

Near-infrared LEDS provide persistent and increasing protection against E. faecalis.

In a previous study, we have shown that non-coherent light-emitting diodes (LEDs) are able to significantly decrease Enterococcus faecalis viability, in vitro. In particular, the concurrent treatment for 5 min with sodium hypochlorite (NaOCl) 1.0% and LED permitted to obtain the total inactivation of the culture. The primary outcome of this study was to verify if the photoinactivation was only temporary or stable over 1 week. The secondary outcome was to verify if using a minor concentration of NaOCl together with LED irradiation, it was possible to reach the total inactivation of the culture. Bacterial suspensions were subjected to different protocols. NaOCl samples were treated with 0.5% sodium hypochlorite for 5 min; LED 5 were subjected to 880-nm LED irradiation for 5 min and LED+NaOCl were contemporary subjected to LED irradiation and 0.5% sodium hypochlorite for 5 min. Then the colony forming units per milliliter (CFU/mL) were analyzed and recorded at 5 min, 24 h, 48 h and 1 week. The data were submitted to ANOVA and LSD post hoc tests at a level of significance of 0.05. Live dead assay and fluorescent microscope observations were also performed for all group at all timing points. The results showed that the 3 protocol treatments were able to decrease significantly the bacterial count respect controls, however, after 5 min, 24 h and 48 h the most effective reduction was measured for NaOCl and NaOCl+LED 5. In the first 48 h LED 5 alone reduced significantly the bacterial count respect controls, but it was higher respect the other tested groups. On the contrary, after 1 week we found an interesting result: samples treated with LED were characterized by a decrement of bacterial count, independently from the addition of sodium hypochlorite. Samples treated with NaOCl alone were characterized by a mild increment of bacterial count, although results were still significant respect C+. The secondary outcome was not confirmed: a concentration of NaOCl 0.5% together with LED irradiation did not permit to reach the total inactivation of the culture.

Effect of a subgingival chlorhexidine chip on the clinical parameters and the levels of alkaline phosphatase activity in gingival crevicular fluid during the non-surgical treatment of periodontitis.

The main therapeutic approaches for inflammatory periodontal diseases include the mechanical treatment of root surfaces. Multi-center clinical trials have demonstrated that the adjunctive use of a chlorhexidine (CHX) chip is effective in improving clinical results compared to scaling and root planing (SRP) alone. However, some recent studies failed to confirm these clinical results, nor have any data been reported regarding the capability of the CHX chip in affecting the activity of alkaline phosphatase (ALP) in the gingival crevicular fluid (GCF). This enzyme has been related to a condition of destructive activity of periodontitis. The aim of this study is to provide further data on the clinical and biochemical effects of CHX chips when used as an adjunct to SRP. Eighty-two systemically healthy patients, aged 31-63, with moderate and advanced periodontitis were recruited from the departments of Periodontology of the University of Chieti. In each patient 2 experimental sites, located in two symmetric quadrants, were chosen with a probing depth of > or = 5 mm and bleeding on probing. The 2 sites were selected randomly at the split-mouth level; control sites received SRP alone, and test sites SRP plus 1 CHX chip. Clinical indices, including probing depth (PPD), clinical attachment level (CAL), bleeding on probing (BOP), and the ALP activity in GCF were evaluated at baseline and after 6 months. Alkaline phosphatase activity was assayed spectrophotometrically. The PPD and CAL were significantly lower at 6 months as compared to the baseline scores in both treatments (p less than 0.01). The PPD reduction was 2.7 mm in the CHX+SRP group and 1.9 mm in the SRP alone group. The CHX+SRP group showed a significantly greater gain of clinical attachment (mean: 1.4 mm) in comparison with the SRP group (mean: 0.9; p less than 0.05). No differences were observed in the decrease of the percent of BOP-positive sites between the experimental groups. Conversely, the CHX+SRP group underwent a significantly greater decrease (p less than 0.01) of the GCF-ALP activity 6 months after treatment in comparison with the SRP alone group. The adjunctive use of the CHX chip resulted in a significant improvement of pocket reduction and clinical attachment gain as compared with SRP alone. These results were concomitant with a significantly greater reduction of the GCF-ALP activity levels.

Enzymatic analysis of the gingival crevicular fluid in hypoxia of high altitude (Everest).

The aim of this study is to determine the qualitative and quantitative changes of alkaline phosphatase (ALP) that occur in the Gingival Crevicular Fluid (GCF) in hypobaric-hypoxic conditions (high altitude). Hypoxia affects systemic adaptation responses in different organs. We examined 17 Caucasians subjects, of whom 13 were mountain climbers (1 female and 12 males), and 4 Tibetans (2 females and 2 males) following exposure to the hypoxia environment of high altitude. The study was conducted at different altitudes (0 m control, 1000 m, 5200 m above sea level) on Mount Everest. The protocol consisted of withdrawing crevicular fluid through the use of cones made of endodontic paper size 30 sectioned to 15 mm from the apex, inserted for 30 seconds in the gingival sulcus (about 2 mm). The analyzed sites were the mesial and distal, buccal and palatal of tooth 1.1 and 2.1. Blood exams were performed on the subjects using I-Stat, furnishing analysis in real time (about 2 mins). In agreement with other results reported in literature, in all the subjects we found an increase in the hematocrit and hemoglobin with a large range of values between them, and with significant differences, as analysed with the Fisher, Scheffe and Bonferroni/Dunn statistical methods. The enzymatic analysis of the GFC showed an increase of the levels of ALP at each altitude studied. With this preliminary study we show that hypoxic environment determines not only the well known cardiovascular systemic responses, but also crevicular fluid adaptation.

Role of the friction free distalize appliance (2FDA)PAT in the molar distalization: photoelastic analysis and alkaline-phosphatase (ALP) activity on first molar and bicuspid.

Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This study describes the effects of one particular molar distalizing appliance, the Friction Free Distalize Appliance (2FDA), in a sample of 20 consecutively treated and growing patients to verify the osteoblastic activity in the compression and traction sites of both the molars and the bicuspids when used as the anchorage teeth. The 2FDA appliances were constructed utilizing a Nickel Titanium open coil spring of 200 gr force in order to distalize the maxillary first molar. The reaction force was controlled utilizing the principle of low/free friction. The results show that the resin around the root of the bicuspid did not discolour at all, which indicates an absence of a force load. On the other hand, on the molar, the resin around the root of the molar became discoloured due to the fact that an orthodontic force was involved with the tooth. To better understand whether the quantity of force that reached the tooth was able to produce osteoblastic recruitment in the sites of tension of the molar and the bicuspid, we quantified an enzyme, the alkaline phosphatase (ALP), present. This measurement allowed us to verify a regular increase of the ALP on the site of molar traction. We also elaborated a mathematical model to evaluate the quantity of force of reaction that produces the device on the bicuspid. Such force results as being 8.34 grams which equals half the pressure of the capillaries of the parodontal ligament (18 grams). The 2FDA appliance compares favourably with other intra-oral distalization devices for the resolution of patients with Class II malocclusions, and is the only distalizing appliance that does not determine osteoclastic/osteoblastic recruitment on the anchorage tooth.

Demineralizing action of EGTA in endodontics.

The demineralization of dentin obtained by treatment with a chelating agent ethylene diamminotetracetic acid (EDTA) or ethylene glycol-bis(beta-aminoethyl ether)-N-tetraacetic acid (EGTA), is a dynamic process involving chelation and solubilization. The actions of the EDTA and EGTA on dentin are influenced by the pH. Increasing mM concentrations of EDTA or EGTA the equivalent pH decreases in a similar slope to 80 mM chelator concentration. Increasing the chelator concentration different data were obtained: with EGTA the pH decreases slightly while with EDTA goes back up to the initial values. After 80 mM, EDTA reduces the activity on the dentin, and EGTA continues to work at higher concentrations. We demonstrated that EGTA solubilized more of 60 percent of dentin while EDTA gives about 20% at the maximal of the solubility.

Pulp-dissolving ability of several endodontic irrigants: a spectrophotometric evaluation.

The aim of this study is to test the dissolving action of different concentrations of NaOCl (0.5%, 2.5% and 5%) and EDTA 17% on bovine pulp tissue, testing solutions at three different times (1, 5, 10 minutes), 100 mg.of dental pulp placed into a becker with 20 ml of solution was evaluated using a spectrophotometer. A solution of NaOCl 5% showed the highest solubility value. Samples treated with 2.5% NaOCl showed solubility values of 0.98 in one minute, 29.1 in five minutes and 57 in ten minutes. Groups treated with NaOCl 0.5% showed small dissolving modifications. 17% EDTA showed the lowest values of solubility. 5% NaOCl solution showed highest pulp dissolving ability, even a 2.5% solution showed high dissolving ability but in longer times.