323,162 research outputs found
Nanotechnological applications in clinical dentistry
No full textAl giorno d'oggi, i progressi delle nanotecnologie hanno rivoluzionato drasticamente tutti i campi dell'odontoiatria, dalle malattie orali alla diagnosi, prevenzione e trattamento. Lo scopo di questa tesi di dottorato è stato quello di indagare e valutare l'applicazione delle nanotecnologie nella pratica clinica, con particolare attenzione all'Odontoiatria Preventiva, Estetica e Restaurativa.
La prevenzione della carie e il trattamento precoce delle lesioni sono sfide prioritarie per il clinico. Il design basato su nanomateriali, che include idrossiapatite sintetica o suoi derivati, è in grado di imitare alcune delle proprietà meccaniche e strutturali dei tessuti calcificati nativi e quindi può promuovere la remineralizzazione della struttura dello smalto e prevenire l'ipersensibilità della dentina. Inoltre, l'impiego di nanotecnologie nell'arricchimento di gel sbiancanti mediante nanoforme di idrossiapatite è ampiamente utilizzato per evitare i disagi e i danni associati ai trattamenti sbiancanti.
Uno dei principali usi delle nanoparticelle nell'Odontoiatria Restaurativa è la loro applicazione come riempitivi nei nanocompositi, fornendo elevata duttilità senza perdita di forza e resistenza ai graffi, con proprietà ottiche, meccaniche e termiche migliorate. Inoltre, i nanocompositi mostrano proprietà estetiche migliorate, come un'elevata ritenzione della brillantezza e un'eccellente lucidabilità e adattabilità. Tra queste caratteristiche migliorate, degne di nota sono quelle mostrate dai nuovi compositi bulk-fill. Infatti, grazie al loro nuovo contenuto di monomero e alle migliorate proprietà di polimerizzazione, i compositi bulk-fill consentono di ottenere rapidamente un adattamento soddisfacente del materiale nella cavità, diminuendo il tempo di seduta necessario, garantendo anche adeguate caratteristiche fisiche della superficie.
Pertanto, l'applicazione delle nanotecnologie supporta e facilita le esigenze del clinico, che richiedono protocolli clinici rapidi, sicuri e ripetibili, per ottenere il miglior risultato in un unico appuntamento.Nowadays, developments in the nanotechnology arena have dramatically revolutionized all fields of dentistry from oral diseases to diagnosis, prevention and treatment. The aim of this PhD thesis was to investigate and evaluate the application of nanotechnologies in clinical practice, with particular attention to Preventive, Aesthetic and Restorative dentistry.
Caries prevention and early treatment of lesions are priority challenges for clinicians. Nanomaterial-based design, which includes synthetic hydroxyapatite or its derivatives, is able to mimic some of the mechanical and structural properties of native calcified tissues and can definitely promote the remineralization of the enamel structure and prevent dentin hypersensitivity. Moreover, the employment of nanotechnologies in the enrichment of whitening gels by means of nano-forms of hydroxyapatite are widely used to avoid the discomfort and damages associated with bleaching treatments.
One of the principal uses of nanoparticles in restorative dentistry is their application as fillers in nanocomposites, providing high ductility without strength loss, scratch resistance, enhanced optical, mechanical and thermal properties. In addition, dental nanocomposites exhibit increased aesthetic properties, such as high gloss retention and excellent polishability and adaptability. Among these ameliorated characteristics, noteworthy are those showed by the new bulk-fill composites. Indeed, due to their novel monomer content and enhanced curing properties, bulk-fill composites let to rapidly obtain a satisfactory adaptation of the material into the cavity, decreasing the chair-time needed, while also ensuring adequate physical characteristics of the surface.
Therefore, the application of nanotechnology supports and facilitates the clinician’s needs, which require rapid, safe and repeatable clinical protocols, to obtain the best result in a single appointment
Su alcuni specifici ambiti di responsabilità professionale in odontoiatria: in chirurgia estrattiva, nel settore protesico ed implantologico e nell’infezione da HIV
No full textIn the last decades the problem of professional responsibility of the doctors went through deep conceptual re-examination. Some criteria, both general and more technically legal, are presented in order to correctly evaluate the professional liability. Then some specific aspects of the object are examined, such as the damaging of the inferior alveolar nerve after dental extraction, the problems concerning dental prosthetics and implants as well as the questions about HIV infection, acquired by patients or collaborators of the dentist, in his office
Whitening Effect by Stain Inhibition from a Chewing Gum with Sodium Hexametaphosphate in a Controlled Twelve-Week Single-Blind Trial
No full textObjective: A twelve-week clinical study was conducted to assess the effect of a chewing gum containing sodium hexametaphosphate (4%) on the inhibition of stain formation. Methodology: Fifty-four subjects were entered and completed all aspects of the study. Twenty-seven of the subjects were smokers, and the other half did not smoke. Subjects were randomly assigned to the test gum or no-gum group. Each participant received a full oral prophylaxis at the beginning of each period of observation. Those chewing the test gum agreed to chew four times a day, for five minutes each time, over twelve weeks. Those assigned to the no-gum group agreed not to chew any gum. After twelve weeks, participants were scored for stain deposits (Lobene Index), received a second oral prophylaxis, and joined the alternate group in this cross-over format. At the end of the twenty-fourth week, all subjects were again scored for stain deposits and the study was completed. In order to enhance stain formation during the entire 24-week study period, all participants received a supply of a chlor-hexidine (0.12%) dentifrice without anionic agents to use three times a day. Stain levels were scored by the same examiner for all measurements and recorded on computer. The examiner was blinded to all treatment assignments. Results: There were no reported problems associated with the chewing gum. The Lobene Index mean score for stain extent was 0.54 (± 0.36) in the test-gum group and 0.81 (± 0.47) for the no-gum group. The difference between the mean scores was highly significant with paired sample t-test (p < 0.001). Mean stain intensity was 0.57 (± 0.38) in the test group and 0.95(± 0.72) in the control group, with a statistically significant difference at p < 0.01. Conclusion: The results indicated that chewing gum containing sodium hexametaphosphate reduced induced stain formation by 33% compared to a no-gum treatment
A one step procedure for luting glass fibre posts: an SEM evaluation
No full textAim: To evaluate the ability of two luting procedures for bonding translucent fibre posts to form resin tags, adhesive lateral branches, and resin dentine interdiffusion zones (RDIZ). Methodology: Forty root filled teeth, extracted for periodontal reasons, were selected for the study. The teeth were randomly divided into four groups of 10 each. Group 1: One Step, light-cured (LC) 20 s + dual link resin cement (LC 20 s); group 2: One Step, not light-cured (NLC) + dual link resin cement (LC 30 s); group 3: One Step (NLC) + dual link resin cement (LC 60 s); group 4: One Step (NLC) + dual link resin cement (LC 90 sec). Forty translucent fibre posts (DT posts, RTD) were inserted. Then, root specimens were processed for scanning electron microscope (SEM) observations to assess the continuity of the RDIZ, the presence or absence of gaps and the density and morphology of resin tags using a four-step scale method. Results: With all luting procedures the formation of a RDIZ occurred. However, the microscopic examination of adhesive interfaces revealed that the percentage of RDIZ was significantly higher in group 1 than in the other three groups (P 0.05). Resin tag formation was evident in all the groups. The characteristic reverse cone shape of resin tags was always noted in the coronal and middle third of all groups, and in the apical third of group 1. In the apical third a shorter length and a less uniform appearance of resin tags were noted in groups 2, 3 and 4. Conclusions: In this laboratory study, when bonding a translucent fibre post into a root canal, the luting procedure including light curing of the adhesive solution before the placement of the cement was more satisfactory, from a SEM standpoint, than the procedure involving the simultaneous curing of adhesive and cement (one step procedure)
A Six-Week Study to Evaluate the Anticalculus Efficacy of a Chewing Gum Containing Pyrophosphate and Tripolyphosphate
No full textObjective: A six-week, double-blind, cross-over clinical study was conducted to compare the effect of a new chewing gum containing pyrophosphate (1%) and tripolyphosphate (1%), versus a control chewing gum on supragingival calculus deposits. Methodology: Twenty-eight adult subjects (mean age 34 ± 8 years) who entered the study were given a full oral prophylaxis and were assigned to chew two pieces of gum, four times a day for five minutes. The gum, either a test chewing gum or placebo chewing gum, was randomly assigned and the subjects were directed to chew their assigned gum for six weeks. All participants also received a 12-week supply of a sodium fluoride (0.32%) dentifrice (Colgate). They were then scored for calculus deposits using the modified Volpe-Manhold Calculus Index (VMI) by the same two examiners. At the end of the first six weeks, the subjects received a second oral prophylaxis and used the alternate chewing gum for a second six-week period of time. The subjects were again scored for calculus deposits and the study was completed. Results: The results demonstrated a mean VMI of 3.65 ± 2.82 for the test group, and a mean of 4.24 ± 3.25 for the placebo group. This difference was significant with paired sample t-test (p < 0.001). Conclusion: These results indicated that chewing gum containing pyrophosphate and tripolyphosphate reduced supragingival calculus formation by 13.9%, compared to the placebo chewing gum
The effect of zinc lactate added tablets on volatile sulfur-containing compounds in the oral cavity
No full textBackground: Oral malodor is defined as breath that is offensive to others and its prevalence is around 35%. Objective: A controlled clinical double-blinded study was conducted to assess the efficacy of sugar-free tablets containing zinc lactate on oral Volatile Sulfur-containing Compounds (VSC) versus placebo tablets. Methods: All participants, who met the inclusion criteria, had to score a level of VSC ≥75 ppb at the basal measurement. Subjects were randomly assigned to one of the groups. The test tablet (0.7g) contained 0.255 mg of zinc lactate; the control tablet was identical but without the active agent. The OralChroma2© device was utilized to evaluate VSC. The levels were recorded at baseline, after sucking two tablets in succession and after 1 hour and 2 hours. Data were analyzed with SPSS and significance was set at α=0.05. Results: 186 subjects completed the trial. The mean reduction from baseline at the end of tablets sucking was, respectively, 43% (p <0.001) in the control and 67% (p <0.001) in the test group, after 1 hour, it was 6% in the control (p=NS) and 25% (p <0.001) in the test group, after 2 hours, it was 3% in the control (p=NS) and 12% (p <0.001) in the test group. The comparison between the two groups after baseline adjustment showed a statistically significant difference for reductions at the end of the sucking period (p <0.001), after 1 hour (p <0.001) and after 2 hours (p <0.05). Conclusion: Tablets containing zinc lactate can statistically reduce the oral VSC levels immediately and for over 2 hours
Crossover clinical trial of tablets containing sodium tripolyphosphate on dental stain formation
No full textObjective: The purpose of this clinical investigation was to evaluate the effectiveness of sugar-free tablets containing sodium tripolyphosphate 2% or sodium tripolyphosphate 0.65%, compared to a no-tablet control in preventing the formation of extrinsic stains over a 12- week period of regular unsupervised use preserving daily oral hygiene with dentifrice and usual tooth brushing. Methods: This was a single-center, examiner-blind, randomized, 12-week crossover clinical trial. Sixty-six adult participants were enrolled in the study and were submitted to a professional cleaning to have a stain-free baseline. They either consumed two sugar-free tablets four times per day or not for 12 weeks. At the crossover, all procedures were repeated and subjects were assigned to another group. Extrinsic stain was measured at each 12-week period by the Modified Lobene Stain Index (MLSI). Results: After the three legs of 12 weeks, 60 subjects completed the trial, their MLSI stain scores showed a significant 35.5% reduction (p < 0.001) in new stain formation for those using the sodium tripolyphosphate 2% tablets, and a significant 23.3% reduction (p < 0.001) in new stain formation for those using the sodium tripolyphosphate 0.65% tablets versus the control group. Conclusion: This clinical study showed that regular use of sugar-free tablets added with sodium tripolyphosphate 2% or 0.65% can reduce stain formation on the anterior teeth respectively by 35.5% (p < 0.001) or 23.3% (p < 0.001), both on facial and lingual/palatal surfaces
Effect on Dental Stains by Potassium Tripolyphosphate Added Chewing Gum
No full textBackground: Today, people worldwide consider the discoloration of teeth the main concern, therefore, dental stains are an important problem for a lot of patients, especially for smokers, and tea and coffee consumers. Objective: This trial was planned to evaluate the effectiveness of a sugar-free chewing gum added with potassium tripolyphosphate, compared to a placebo chewing gum on the development or the removal of dental extrinsic stains preserving regular daily oral hygiene. Methods: This was a single-center, double-blind, randomized, 6-week parallel controlled clinical trial. Among those who were eligible for the trial, 162 adult participants were randomly allocated into two groups of 81 each and were instructed to maintain customary oral hygiene. All subjects started the trial period after an in-office dental visit to set the stain index baseline. They chewed one of the two chewing gums for six weeks, five pieces per day, preferably after meals and snacks, for 10 minutes. Both chewing gums were sugar-free, 2g of weight with the same size and shape. The test chewing gum contained potassium tripolyphosphate (24.4 mg per piece), the control chewing gum was identical without potassium tripolyphosphate, therefore, it did not contain any anti-stain agent. The dental extrinsic stain was measured at the first visit and at the end of six weeks by the Modified Lobene Stain Index (MLSI). Comparisons between the groups were performed using ANOVA after adjustment of the baselines, and comparisons between initial and final indexes inside the groups were performed using paired t-tests. Results: After the 6 weeks, 154 subjects completed the trial, 77 in each group. The mean difference in stain composite index for all sites after six weeks was 0.04±0.07 in the control group and-0.03±0.07 in the test group. This difference was statistically significant after baseline adjustment (p<0.001). Moreover, the differences in stain indexes for both buccal or lingual-palatal sites showed a statistically significant difference (p<0.001) for those using the test chewing gum versus the control chewing gum. Conclusion: The overall findings of this clinical study suggest that the use of chewing gum containing potassium tripolyphosphate can reduce dental stains versus placebo chewing gum on frontal teeth after six weeks of maintaining regular oral hygiene with normal tooth brushing
The effect of zinc acetate and magnolia bark extract added to chewing gum on volatile sulfur-containing compounds in the oral cavity
No full textObjective: A controlled, clinical, double-blind study was conducted to assess the efficacy of a sugar-free chewing gum containing zinc acetate and magnolia bark extract (MBE) on oral volatile sulfur-containing compounds (VSC) versus a placebo sugar-free chewing gum for two hours. Methods: To participate in the study, subjects had to have at least 24 of their teeth, no report of oral and systemic diseases, and no removable dentures. All 168 eligible participants had to avoid any professional oral hygiene, refrain from taking medicine for two weeks, and not be menstruating. They were also instructed not to brush their teeth and tongue, smoke, drink alcohol, or eat onion, garlic, or licorice for the six-hour period before the visit and during the test. Moreover, to join the protocol, they had to show a VSC score of > 75 ppb at the baseline measurement. One-hundred and twenty-three subjects (67 men and 56 women, mean age 37) met the criteria at baseline and were entered into either the test or control group by assignment from a table of randomized numbers. The test chewing gum (2.23 g) contained zinc acetate 0.012% and magnolia bark extract 0.15% in weight; the control gum was equivalent without these active agents. The OralChromaTM device was utilized to evaluate total oral VSC. Their levels were recorded at baseline, after ten minutes of mastication, after one hour, and after two hours. Data were analyzed with SPSS software and the level of significance was set at a = 0.05. Results: One-hundred and twenty-three subjects completed the trial (62 in the control group and 61 in the test group); none reported problems linked to zinc acetate or magnolia bark extract. The mean percentage reductions from baseline at the end of the 10-minute chewing were 31.2% in the control group (p < 0.05) and 50.9% in the test group (p < 0.05). One hour later the reductions were 6.9% in the control group and 27.6% in the test group (p < 0.05); two hours later the reductions were 2.3% in the control group and 13.6% in the test group. The comparison of the two groups after baseline adjustment showed a statistically significant difference (p < 0.05) in VSC reductions between the test and control chewing gums at the end of the mastication period and after one hour. Conclusion: Chewing gum containing zinc acetate and magnolia bark extract can significantly reduce the oral VSC levels for more than one hour. Moreover, the test chewing gum reduces oral VSC significantly more than a control chewing gum
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