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Calheiros F.C.,Ibirapuera University | Daronch M.,NY University | Rueggeberg F.A.,Georgia Regents University | Braga R.R.,University of Sao Paulo
Dental Materials | Year: 2014

Objective To test the following hypotheses: (1) degree of conversion (DC) and polymerization stress (PS) increase with composite temperature (2) reduced light-exposure applied to pre-heated composites produces similar conversion as room temperature with decreased PS. Methods Composite specimens (diameter: 5 mm, height: 2 mm) were tested isothermally at 22 °C (control), 40 °C, and 60 °C using light-exposures of 5 or 20 s (control). DC was accessed 5 min after light initiation by FTIR at the specimen bottom surface. Maximum and final PS were determined, also isothermally, for 5 min on a universal testing machine. Non-isothermal stress was also measured with composite maintained at 22 °C or 60 °C, and irradiated for 20 s at 30 °C. Data were analyzed using two-way ANOVA/Tukey and Student's t-test (α = 5%). Results Both DC and isothermal maximum stress increased with temperature (p < 0.001) and exposure duration (p < 0.001). Isothermal maximum/final stress (MPa) were 3.4 ± 2.0b/3.4 ± 2.0A (22 °C), 3.7 ± 1.5b/3.6 ± 1.4A (40 °C) and 5.1 ± 2.0a/4.0 ± 1.6A (60 °C). Conversion values (%) were 39.2 ± 7.1c (22 °C), 50.0 ± 5.4b (40 °C) and 58.5 ± 5.7a (60 °C). The reduction of light exposure duration (from 20 s to 5 s) with pre-heated composite yielded the same or significantly higher conversion (%) than control (22 °C, 20 s/control: 45.4 ± 1.8b, 40 °C, 5 s s: 45.1 ± 0.5b, 60 °C, 5 s s: 53.7 ± 2.7a, p < 0.01). Non-Isothermal conditions showed significantly higher stress for 60 °C than 22 °C (in MPa, maximum: 4.7 ± 0.5 and 3.7 ± 0.4, final: 4.6 ± 0.6 and 3.6 ± 0.4, respectively). Clinical significance: Increasing composite temperature allows for reduced exposure duration and lower polymerization stress (both maximum and final) while maintaining or increasing degree of conversion. © 2014 Academy of Dental Materials.


PubMed | University of Connecticut Health Center, São Paulo State University, Southern Cross University of Brazil, University of Sao Paulo and Ibirapuera University
Type: Journal Article | Journal: Journal of biomedical optics | Year: 2015

This research analyzed the quality of resin-based sealer adaptation after intracanal laser irradiation. Extracted teeth (n = 168) were root canal treated and divided into four groups, according to dentin surface treatment: no laser; Nd:YAG laser (1.5 W, 100 mJ, 15 Hz); diode laser (2.5 W in CW), and Er:YAG laser (1 W, 100 mJ, 10 Hz). The teeth were divided into four subgroups according to the sealer used: AH Plus, EndoREZ, Epiphany, and EpiphanySE. For testing the sealing after root canal obturation, the penetration of silver nitrate solution was measured, whereas to evaluate the adaptation and penetration of the sealer into the dentin, environmental scanning electron microscopy (ESEM) was used. The ESEM images were analyzed using a four-grade criteria score by three evaluators. The inter-examiner agreement was confirmed by Kappa test and the scores statistically compared by the Kruskal-Wallis test (p < 0.05). Both adaptation and sealer penetration in root canals were not affected by the laser irradiation. Nd:YAG and diode laser decreased the tracer penetration for AH Plus, whereas EndoREZ and EpiphanySE performances were affected by Nd:YAG irradiation (p < 0.05). It can be concluded that intracanal laser irradiation can be used as an adjunct in endodontic treatment; however, the use of hydrophilic resin sealers should be avoided when root canals were irradiated with Nd:YAG laser.


PubMed | University of Santo Amaro, University of Sao Paulo and Ibirapuera University
Type: Journal Article | Journal: Clinical oral investigations | Year: 2016

This study aims to correlate patient-reported reactions with in vitro analyses of the pH, abrasive quality, and cytotoxicity of four toothpastes.One hundred twenty-one patients received non-identified samples of toothpaste to be used for 6 days and answered a questionnaire about their sensations. In vitro analysis: the pH of toothpastes was measured with a pH meter. The abrasivity of toothpastes was evaluated against composite resin specimens (n=10). A toothbrushing machine was used to simulate wear, which was indirectly measured by mass loss using a scale. Cell culture media conditioned with toothpaste were used to assess the cytotoxicity. Confluent cells were kept in contact with the conditioned media or control for 24 h. The cell viability was measured using the 3-(bromide, 4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium (MTT)-reduction assay. The obtained data on the pH, weight loss, and cell viability were compared by ANOVA/Tukeys tests (p<0.05).With the exception of the bleaching effect paste, the Oral B paste produced the highest frequencies of irritation reports, tooth sensitivity, taste discomfort, and texture discomfort in the clinical study; patients also reported rougher teeth, soft tissue peeling, dry mouth, thrush, tingling, and taste changes in response to this paste. The in vitro analysis demonstrated that Oral B had the lowest pH, the highest abrasivity, and produced the lowest cell viability (p<0.01).Results suggest that low pH toothpastes that are highly abrasive and cytotoxic may cause undesirable reactions in patients.Toothpastes properties should be well known for indication to patient therefore minimizing discomfort reports.


PubMed | Southern Cross University of Brazil, Federal University of Juiz de fora, University of Sao Paulo and Ibirapuera University
Type: Journal Article | Journal: Brazilian oral research | Year: 2016

Dental trauma in immature permanent teeth can damage pulp vascularization, which leads to necrosis and cessation of apexogenesis. Studies on tissue engineering using stem cells from human exfoliated deciduous teeth (SHEDs) have yielded promising results. Laser phototherapy (LPT) is able to influence the proliferation and differentiation of these cells, which could improve tissue engineering. SHEDs (eighth passage) were seeded into 96-well culture plates (103 cells/well) and were grown in culture medium supplemented with 15% defined fetal bovine serum (FBS) for 12 h. After determining the appropriate nutrition deficiency status (5% FBS), the cells were assigned into four groups: 1) G1 - 15% FBS (positive control); 2) G2 - 5% FBS (negative control); 3) G3 - 5% FBS+LPT 3 J/cm2; and 4) G4 - 5% FBS+LPT 5 J/cm2. For the LPT groups, two laser irradiations at 6 h intervals were performed using a continuous wave InGaAlP diode laser (660 nm, with a spot size of 0.028 cm2, 10 mW) in punctual and contact mode. Cell viability was assessed via an MTT reduction assay immediately after the second laser irradiation (0 h) and 24, 48, and 72 h later. We found that G3 and G4 presented a significantly higher cell growth rate when compared with G2 (p < 0.01). Moreover, G4 exhibited a similar cell growth rate as G1 throughout the entire experiment (p > 0.05). These findings indicate that LPT with 5 J/cm2 can enhance the growth of SHEDs during situations of nutritional deficiency. Therefore, LPT could be a valuable adjunct treatment in tissue engineering when using stem cells derived from the dental pulp of primary teeth.


PubMed | University of Santo Amaro, University of Sao Paulo and Ibirapuera University
Type: Journal Article | Journal: Brazilian oral research | Year: 2016

Nowadays, the main reasons for replacement of resin-based composite restorations are fracture or problems with the integrity of their interface, such as marginal staining, microleakage, or secondary caries. The aim of the present study was to evaluate the influence of the organic matrix on polymerization stress (PS), degree of conversion (DC), elastic modulus (E), flexural strength (FS), Knoop hardness (KHN), sorption (SP), and solubility (SL). In order to obtain a material which combines better mechanical properties with lower PS, seven experimental composites were prepared using BisGMA to TEGDMA molar ratios of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 and 8:2 and 40% of silica. PS was obtained in a universal testing machine, using acrylic as bonding substrate. DC was determined using Fourier Transform Raman spectroscopy. E and FS were obtained by the three-point bending test. KHN was measured by a microindentation test using a load of 25 g for 30 s. SP and SL were assessed according to ISO 4049. The data were submitted to one-way ANOVA. The increase in BisGMA concentration resulted in the decrease of PS, DC, E, FS and KHN. However, it did not change the SP and SL values. FS, E and KHN showed a strong and direct relationship with the DC of the materials. The composite material with a BisGMA to TEGDMA molar ratio of 1:1 was the one with better mechanical properties and lower PS.


PubMed | University of Sao Paulo and Ibirapuera University
Type: Journal Article | Journal: Odontology | Year: 2016

The aim of this study was to evaluate the influence of the physical assessment of different light-curing units from 55 dental offices on the irradiance and composite microhardness top/bottom ratio, and the influence of the radiometers for LED or QTH light sources on irradiance measurement. The irradiance of each light-curing unit was evaluated with two radiometers, either for LED or QTH light. A questionnaire regarding the type of source (LED or QTH), time of use, date of last maintenance and light-curing performance assessment applied. The physical assessments were evaluated regarding damage or debris on the light tip. For each light-curing unit, three composite specimens were made (diameter=7mm; thickness=2mm) with polymerizing time of 20s, in order to perform the microhardness (Knoop) test. Data were analyzed by Kruskal-Wallis and Dunn test (=0.01). There was wide variation in irradiance (0-1000 mW/cm(2)). Approximately 50% of the light-curing units presented radiation lower than 300mW/cm(2); 10% of light-curing units, especially those with LED source, presented values higher than 800 mW/cm(2), and 43% of light-curing units worked with adequate irradiance between 301 and 800 mW/cm(2). In almost 60% of cases, no maintenance of light-curing units was performed in a period of 3 to 10 years. The age of the light-curing units and the use of inadequate tips interfered negatively in irradiance. The data emphasize the importance of periodic maintenance of light-polymerizing, light-curing units.


PubMed | University of Sao Paulo and Ibirapuera University
Type: | Journal: TheScientificWorldJournal | Year: 2015

Recurrent aphthous ulcers (RAUs) are the most common lesion found in the oral cavity. There is no definitive cure for RAUs and current treatments are aimed at minimizing symptoms. Since low-level laser therapy (LLLT) modulates inflammatory responses, and promotes pain reduction and cellular biostimulation, LLLT can be suggested as an alternative treatment for RAUs. The literature concerning the potential of LLLT in the treatment of RAUs was evaluated. A systematic literature review identified 22 publications, of which only 2 studies were adopted. The eligibility criteria consisted of randomized controlled trials (RCTs). Both RCTs achieved significant results concerning LLLT and pain-level reductions and reduced healing times. Despite the variance in irradiation conditions applied in both studies, very similar wavelengths were adopted. There is accordingly strong evidence that wavelength plays an important role in RAU treatment. Taking into account the different parameters applied by selected RCTs, it is not possible to suggest that a specific protocol should be used. However, in light of the significant results found in both studies, LLLT can be suggested as an alternative for RAU treatment. Additional RCTs should be performed in order to reach a clinical protocol and better understand the application of LLLT in RAU treatment.


PubMed | Federal University of São Paulo and Ibirapuera University
Type: | Journal: Hormones and behavior | Year: 2016

REM sleep rebound is a common behavioural response to some stressors and represents an adaptive coping strategy. Animals submitted to multiple, intermittent, footshock stress (FS) sessions during 96h of REM sleep deprivation (REMSD) display increased REM sleep rebound (when compared to the only REMSD ones, without FS), which is correlated to high plasma prolactin levels. To investigate whether brain prolactin plays a role in stress-induced REM sleep rebound two experiments were carried out. In experiment 1, rats were either not sleep-deprived (NSD) or submitted to 96h of REMSD associated or not to FS and brains were evaluated for PRL immunoreactivity (PRL-ir) and determination of PRL concentrations in the lateral hypothalamus and dorsal raphe nucleus. In experiment 2, rats were implanted with cannulas in the dorsal raphe nucleus for prolactin infusion and were sleep-recorded. REMSD associated with FS increased PRL-ir and content in the lateral hypothalamus and all manipulations increased prolactin content in the dorsal raphe nucleus compared to the NSD group. Prolactin infusion in the dorsal raphe nucleus increased the time and length of REM sleep episodes 3h after the infusion until the end of the light phase of the day cycle. Based on these results we concluded that brain prolactin is a major mediator of stress-induced REMS. The effect of PRL infusion in the dorsal raphe nucleus is discussed in light of the existence of a bidirectional relationship between this hormone and serotonin as regulators of stress-induced REM sleep rebound.


PubMed | Ibirapuera University
Type: Journal Article | Journal: Current opinion in endocrinology, diabetes, and obesity | Year: 2016

This review summarizes recent evidence on the impact of osteoporosis on periodontonlogy and implant dentistry, prevalence of diseases, pathophysiology and treatment outcomes.Patients with osteoporosis should be advised about the importance of returning for periodical periodontal maintenance as inadequate oral care may lead to a faster development of periodontitis. There is no definitive information on the development of bisphosphonate-related osteonecrosis of the jaw associated with dental implant therapy. Patients presenting severe periodontitis, undergoing intravenous bisphosphonate therapy (for long-term periods) and submitted to more invasive periodontal/peri-implant surgical procedures (that can promote superior dentoalveolar surgical trauma) might be advised about the possibility of developing bisphosphonate-related osteonecrosis of the jaw following dental therapy. Thus, individualized risk evaluation must be undertaken by both the medical and dental teams prior to any dental treatment.The most recent literature on the impact of osteoporosis on the periodontal and peri-implant tissues was reviewed to emphasize the importance of oral hygiene measures, and the combined medical/dental assessment of importance when osteoporotic patients are in need of dentoalveolar surgical procedures (e.g. tooth extraction and dental implant placement).


Chambrone L.,Ibirapuera University
Current Opinion in Endocrinology, Diabetes and Obesity | Year: 2016

PURPOSE OF REVIEW: This review summarizes recent evidence on the impact of osteoporosis on periodontonlogy and implant dentistry, prevalence of diseases, pathophysiology and treatment outcomes. RECENT FINDINGS: Patients with osteoporosis should be advised about the importance of returning for periodical periodontal maintenance as inadequate oral care may lead to a faster development of periodontitis. There is no definitive information on the development of bisphosphonate-related osteonecrosis of the jaw associated with dental implant therapy. Patients presenting severe periodontitis, undergoing intravenous bisphosphonate therapy (for long-term periods) and submitted to more invasive periodontal/peri-implant surgical procedures (that can promote superior dentoalveolar surgical trauma) might be advised about the possibility of developing bisphosphonate-related osteonecrosis of the jaw following dental therapy. Thus, individualized risk evaluation must be undertaken by both the medical and dental teams prior to any dental treatment. SUMMARY: The most recent literature on the impact of osteoporosis on the periodontal and peri-implant tissues was reviewed to emphasize the importance of oral hygiene measures, and the combined medical/dental assessment of importance when osteoporotic patients are in need of dentoalveolar surgical procedures (e.g. tooth extraction and dental implant placement). Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

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