Botulinum Toxin A in the Management of a Gummy Smile: A Clinical Controlled Preliminary Study.

BACKGROUND: Botulinum toxin type A (BTX-A) is recent technique for the treatment of gummy smile. OBJECTIVES: The aim of this randomized controlled preliminary clinical trial was to evaluate the effects of BTX-A on excessive gingiva display (EGD) reduction, muscle activity, and patient satisfaction at 2, 8, 12, 16, 21, and 25 weeks. METHODS: Group 1 (G1) received 4 points of BTX-A application (2 U/point) for relaxation of the levator labii superioris alaeque nasi and levator labii superioris muscles; Group 2 (G2) received 2 points of BTX-A (2 U/point) for relaxation of only the levator labii superioris alaeque nasi muscle. RESULTS: A high dropout of patients from follow-up sessions occurred. Therefore, because of this data limitation, the results were considered a preliminary outcome. At 2 weeks, there was a significant difference between baseline regarding the reduction of EGD in G1 and G2, reduction in muscle activity in G1, and increased satisfaction in G1 and G2. At 2 weeks, there was no difference between the 2 groups. Statistically significant EGD reduction was maintained until 16 weeks in G2 and 25 weeks in G1. After 14 days there was a gradual recovery of muscle activity in both groups until recovery of baseline values by 25 weeks. Patients' satisfaction with treatment lasted 21 weeks in G1 and 16 weeks in G2. CONCLUSIONS: Increasing the number of BTX-A injection points resulted in a prolonged effect regarding EGD reduction and patient satisfaction but did not increase the intensity of the outcome. However, due to the high dropout of patients, this is a preliminary conclusion and further studies are necessary to confirm these results.

Effect of the attachment system on the biomechanical and clinical performance of overdentures: A systematic review.

STATEMENT OF PROBLEM: Overdentures can improve the quality of life of elderly patients compared with conventional complete dentures. Different attachment systems can be used to retain these prostheses, but which system results in better function, mechanical performance, and patient comfort is unclear. PURPOSE: The purpose of this systematic review was to evaluate randomized clinical trials to compare overdentures supported by either bar and clip or ball and O-ring attachments for retention, masticatory efficiency, bone loss, and patient satisfaction. MATERIAL AND METHODS: A literature search was conducted in the PubMed and Web of Science databases. From 163 studies, 16 randomized clinical trials were included in this systematic review based on the inclusion and exclusion criteria. The risk of bias was evaluated according to the RevMan software Risk of Bias Table (RoB Table), and only the studies with a low or intermediate risk of bias were included in the review. RESULTS: From the limited number of studies, the attachment type did not affect the masticatory quality of the patients, bone loss marginal to the implants, or the degree of patient satisfaction. However, overdentures with the bar and clip attachment tended to have higher initial retention than the ball and O-ring system. CONCLUSIONS: Both the bar and clip and ball and O-ring attachment systems presented similar clinical performance regarding mechanical and functional properties and patient satisfaction.

The impact of chitosan in experimental resin with different photoinitiator systems.

OBJECTIVE: to investigate the effect of different concentrations of chitosan added to experimental resins containing either BAPO or camphorquinone (CQ) as photoinitiators, regarding degree of conversion (DC), flexural strength (FS), flexural elastic modulus (E), Knoop microhardness (KHN), cytotoxicity, genotoxicity and antimicrobial activity. METHODS: Experimental resins with polymeric matrix of BisGMA and TEGDMA was added either 0.5 wt% BAPO or 0.5 wt% camphorquinone/0.2% amine along with and chitosan concentrations of 0.5%; 1.0% or 2.0%. Degree of conversion was measured using Fourier transformed infrared spectroscopy. Flexural strength and elastic modulus were obtained through three-point bending test and Knoop microhardness was measured in a microidenter. Direct cytotoxicity was performed in human keratinocytes and genotoxicity test was done in murine macrophages cells. Antimicrobial activity was acessed against Staphylococcus aureus and Streptococcus mutans through the inhibition halo. Data were analyzed using two-way ANOVA and Tukey teste (α = 0.05). RESULTS: The materials containing photoinitiator BAPO showed higher values of DC, FS, E, and KHN compared to resins with CQ. The addition of chitosan did not affect the properties of these materials. However, in resins containing CQ, the addition of chitosan improve these properties compared to control group. For the groups containing BAPO the chitosan reduced cytotoxicity and genotoxicity compared to materials with camphorquinone. The materials with 1.0% and 2.0% chitosan showed increased antibacterial activity in the materials containing BAPO as photoinitiator for both bacteria. SIGNIFICANCE: The alternative photoinitiator BAPO and chitosan can improve physical and biological properties of photoactivated resins when compared with the materials with photoinitiator camphorquinone.

Antimicrobial and optical properties of a new biogenic silica-coated silver nanoparticles incorporated into experimental resin.

Background: Evaluate the effects of incorporating silica-coated silver nanoparticles (Ag@SiO2 NPs) into odontological clinic resin materials. Material and Methods: Silver nanoparticles coated with silicon dioxide were added to the experimental resin matrix at 1, 3, and 5wt%. Degree of conversion (DC), optical properties (total transmittance and color change), and microstructural analysis were evaluated. Materials were tested for silver ion release, cytotoxicity in dental pulp fibroblasts, Streptococcus mutans biofilm growth by Colony-Forming Unit (CFU) and confocal laser scanning microscopy (CLSM). Results: Groups had a similar DC, despite significant differences observed in transmittance and color change analysis for all groups with NPs. Silver ion release values were below the detection limit after 72h for all groups, and NPs incorporation did not show a statistical difference from the control on pulp fibroblasts assay. After 72h, the CFU count was significantly reduced by 74% from 3wt% of Ag@SiO2NPs. CLSM evaluation on S. mutans colonies showed a dose-dependent decrease in the emitted fluorescence. Conclusions: The application of Ag@SiO2 NPs in a resinous matrix, demonstrates a significant reduction of S. mutans CFU in oral biofilm, at concentrations from 3wt%, without an increase in cytotoxicity. The reduced transmittance values did not affect the DC, although a significant color change was perceived in all concentrations. Key words:Nanoparticles, Silver Compounds, Composite Dental Resin, Anti-Bacterial Agent, Optical Imaging.

Pro-angiogenic potential of a functionalized hydrogel scaffold as a secretome delivery platform: An innovative strategy for cell homing-based dental pulp tissue engineering.

Angiogenesis is a key process that provides a suitable environment for successful tissue engineering and is even more crucial in regenerative endodontic procedures, since the root canal anatomy limits the development of a vascular network supply. Thus, sustainable and accelerated vascularization of tissue-engineered dental pulp constructs remains a major challenge in cell homing approaches. This study aimed to functionalize a chitosan hydrogel scaffold (CS) as a platform loaded with secretomes of stem cells from human exfoliated deciduous teeth (SHEDs) and evaluate its bioactive function and pro-angiogenic properties. Initially, the CS was loaded with SHED secretomes (CS-S), and the release kinetics of several trophic factors were assessed. Proliferation and chemotaxis assays were performed to analyze the effect of functionalized scaffold on stem cells from apical papilla (SCAPs) and the angiogenic potential was analyzed through the Matrigel tube formation assay with co-cultured of human umbilical vein endothelial cells and SCAPs. SHEDs and SCAPs expressed typical levels of mesenchymal stem cell surface markers. CS-S was able to release the trophic factors in a sustained manner, but each factor has its own release kinetics. The CS-S group showed a significantly higher proliferation rate, accelerated the chemotaxis, and higher capacity to form vascular-like structures. CS-S provided a sustained and controlled release of trophic factors, which, in turn, improved proliferation, chemotaxis and all angiogenesis parameters in the co-culture. Thus, the functionalization of chitosan scaffolds loaded with secretomes is a promising platform for cell homing-based tissue engineering.

Effects of the crosslinking of chitosan/DCPA particles in the antimicrobial and mechanical properties of dental restorative composites.

The development of restorative materials containing antibacterial agents is an alternative to reduce the progression of caries lesions. OBJECTIVE: to compare the influence of the degree of crosslinking of chitosan particles loaded with dibasic calcium phosphate (DCPA) on the mechanical properties, degree of conversion (DC), and antimicrobial properties of experimental composites. METHODS: Chitosan/DCPA particles were synthesized by the electrospraying, crosslinked by 0, 8, or 16 h in glutaraldehyde, and characterized by zeta potential and minimum inhibitory concentration (MIC) against S. mutans. Experimental resin composites of Bis-GMA and TEGDMA and 59.5% of barium glass were synthesized, chitosan/DCPA particles were added at 0 or 0.5 wt% with the different crosslinking time. The materials were subject to DC analysis, three-point bending test at 24 h and 7 days, and antimicrobial assays. Data were submitted to one-way ANOVA and Tukey test (α = 0.05). RESULTS: The particles with longer crosslinking time presented higher zeta potential and MIC, and the composite containing these particles showed significantly higher biofilm inhibition than the control group. The other two groups were similar to each other and the control. The composite containing particles with 88 h crosslinking time showed the lowest flexural strength at 7 days in water, and materials with non-crosslinked particles and longer crosslinking time presented flexural strength similar to control. The flexural modulus and DC showed no statistical difference among groups. SIGNIFICANCE: composite resin containing 0.5% chitosan/DCPA particles crosslinked by 16 h showed a reduction of biofilm formation without affecting the mechanical properties in relation to the control.

Comparison of two-step versus four-step composite finishing/polishing disc systems: evaluation of a new two-step composite polishing disc system.

OBJECTIVE: The purpose of this study was to evaluate surface finish and gloss of a two-step composite finishing/polishing (F/P) disc system compared with two multistep systems on five composites. METHODS: Seventy-five disc-shaped composite specimens (D=10.0 mm, 2 mm thick, n=15 per composite) were made of microfill (Durafill-D), nanofill (Filtek Supreme-FS), nanohybrid (Premise-PR), and microhybrids (Filtek Z250-FZ, Esthet-EX). One side of each specimen was initially finished with a carbide bur. Five specimens of each resin composite were randomly assigned to receive full F/P by each of the disc systems: two-step (Enhance Flex NST-EF) and four-step (Sof-Lex-SL, Super-Snap-SS). Surface gloss was measured with a glossmeter and surface roughness was measured with a profilometer. Results were analyzed by two-way analysis of variance (ANOVA)/Tukey's (α<0.05). RESULTS: No difference in gloss was noted among the three F/P systems when used with D and EX; no difference between SL and EF when used with any composite, except for FS; and no difference between SL and SS when used with any composite. SL and EF showed similar surface roughness when used on all composites, except for EX. EF and SS showed similar surface roughness on PR. SL and SS showed similar surface roughness values on every composite, except for FZ. CONCLUSIONS: EF was capable of providing similar gloss and surface roughness to SL on four composites evaluated but was not able to produce as glossy or as smooth a surface as SS for three of the five composites.

Influence of 35% hydrogen peroxide gel renewal on color change during in-office dental photobleaching with violet LED: A split-mouth randomized controlled clinical trial.

BACKGROUND: To clinically evaluate the effect of 35% hydrogen peroxide gel renewal in association with violet LED (405-410nm) through a split-mouth randomized controlled clinical trial. METHODS: The treatment consisted in 3 bleaching sessions of 15 min each, with an interval of 7 days between them, using 35% hydrogen peroxide combined to violet LED irradiation. Selected patients had two experimental segments for the split-mouth design: No change of the bleaching gel during each session (NBGR) and 3 changes of the bleaching gel every 5 min for each session (BGR). During the 3 bleaching sessions, the selected quadrant received the same treatment. Patients had their upper canines and central incisors teeth color measured with a subjective (color scale - VITA Classical) and an objective (spectrophotometer - VITA Easyshade) method and their teeth sensitivity measured using a Visual Analog Scale (VAS) before, immediately after each bleaching session, and 14 days and 2 months (60 days) after the end of the treatment. RESULTS: The protocol adopted in the present study reached satisfactory results regarding color change. No statistical difference between groups was observed immediately after the end of the treatment and in the follow-up analysis for both subjective and objective color evaluation. No difference in tooth sensitivity between segments was observed. CONCLUSION: There is no need for bleaching gel renewal when following the clinical protocol of 3 sessions of 15 min in a bleaching protocol of 35% hydrogen peroxide combined with violet LED.

Physical and Biological Properties of a Chitosan Hydrogel Scaffold Associated to Photobiomodulation Therapy for Dental Pulp Regeneration: An In Vitro and In Vivo Study.

BACKGROUND: The regeneration of dental pulp, especially in cases of pulp death of immature teeth, is the goal of the regenerative endodontic procedures (REPs) that are based on tissue engineering principles, consisting of stem cells, growth factors, and scaffolds. Photobiomodulation therapy (PBMT) showed to improve dental pulp regeneration through cell homing approaches in preclinical studies and has been proposed as the fourth element of tissue engineering. However, when a blood clot was used as a scaffold in one of these previous studies, only 30% of success was achieved. The authors pointed out the instability of the blood clot as the regeneration shortcoming. Then, to circumvent this problem, a new scaffold was developed to be applied with the blood clot. The hypothesis of the present study was that an experimental injectable chitosan hydrogel would facilitate the three-dimensional spatial organization of endogenous stem cells in dental pulp regeneration with no interference on the positive influence of PBMT. METHODS: For the in vitro analysis, stem cells from the apical papilla (SCAPs) were characterized by flow cytometry and applied in the chitosan scaffold for evaluating adhesion, migration, and proliferation. For the in vivo analysis, the chitosan scaffold was applied in a rodent orthotopic dental pulp regeneration model under the influence of PBMT (660 nm; power output of 20 mW, beam area of 0.028 cm2, and energy density of 5 J/cm2). RESULTS: The scaffold tested in this study allowed significantly higher viability, proliferation, and migration of SCAPs in vitro when PBMT was applied, especially with the energy density of 5 J/cm2. These results were in consonance to those of the in vivo data, where pulp-like tissue formation was observed inside the root canal. CONCLUSION: Chitosan hydrogel when applied with a blood clot and PBMT could in the future improve previous results of dental pulp regeneration through cell homing approaches.

Effect of three different attachment designs in the extrusive forces generated by thermoplastic aligners in the maxillary central incisor.

INTRODUCTION: Orthodontic aligners use have increased in dentistry. The resolution of complex movements such as extrusion demands the use of attachments to reach the aimed force, but just a few studies have been developed to evaluate the biomechanical performance of the aligners and their accessories. OBJECTIVE: The objective of this study was to evaluate on the three axes (X, Y and Z) the forces generated by three different attachment designs for the extrusion of the maxillary central incisor using esthetic orthodontic aligners. METHODS: Three prototypes of maxillary models were developed, each one with a specific attachment inserted in the central incisor. Three aligners were manufactured for each of the three attachment designs, with 0.33-mm activation in the direction of the extrusion. An analytical device was used to evaluate the forces applied to the three axes by each aligner/attachment. The data were assessed by one-way ANOVA and Tukey's test (α = 0.05). RESULTS: All of the studied attachment designs could satisfactorily perform the extrusion movement. However, force intensities were different in the three designs (design 1 = 2.5 N; design 2 = 2.2 N, and design 3 = 1.1 N). Furthermore, two of the three attachment designs (designs 1 and 2) eventually exerted significant forces on the X (mesiodistal) and Y (buccopalatal) axes. CONCLUSION: The attachment design 3 presents the best distribution of forces for extrusion movement, generating almost null forces on X and Y axes, and lower intensity of force on the Z axis.

Knowledge, attitudes, and practices of undergraduate students concerning Regenerative Endodontics.

BACKGROUND: Knowledge, attitudes, and beliefs of the students are important for the Tissue Engineering in Endodontic practice. The opinion of these future dentists would ultimately will decide the endurance of REPs as routine procedures in endodontic practice. The aim of this study was to perform a survey to identify the knowledge, attitudes, and practices of undergraduate students about regenerative endodontic procedures (REPs). METHODS: The questionnaire was obtained after cross-cultural adaptation of a questionnaire previously applied in USA and was applied to two hundred forty-eight undergraduates. Data were statistically analyzed. RESULTS: Most of the students (82.9%) agreed that regenerative therapy should be incorporated to dentistry and 87.5% of them believed that stem cells banks would be useful for the tissue regeneration. Most participants (58.1%) would like to obtain an internship/tutoring that addresses REPs and 80.8% of participants think that the major obstacle to a patient accepting a REP was the expected high cost of the treatment. The freshmen students were more optimistic about offering stem cell treatments to their patients (P≤0.05). CONCLUSIONS: The undergraduates were very optimistic about the future of REPs, stem cell banking, and tissue engineering. Although seniors demonstrated less enthusiasm towards REPs than the freshman, most students are willing to recommend these treatments to their patients.

Biogenic synthesis and antimicrobial activity of silica-coated silver nanoparticles for esthetic dental applications.

OBJECTIVES: this study aimed to synthesize AgNPs from green tea (GT) extract, forming GT-AgNPs, and to coat their surfaces with silica, resulting in light-colored Ag@SiO2 nanoparticles. MATERIALS AND METHODS: particles were characterized and tested for minimal inhibitory concentration (MIC), biofilm formation against Streptococcus mutans and cytotoxicity evaluation on dental pulp fibroblasts. RESULTS: X-ray diffraction (XRD) confirmed the formation of pure AgNPs, whereas energy dispersive X-ray spectroscopy (EDS) mapped their elemental atoms. Dynamic light scattering (DLS) demonstrated formation of particles at nanoscale, with moderate polydispersity and negative zeta potential, in agreement with nanoparticle tracking analysis (NTA) size measurements. Fourier-transformed infrared (FTIR) spectroscopy confirmed the successful condensation of silica, which significantly increased surface area by 50%, as assayed by surface area analysis (BET). Thermogravimetric analysis showed a 18%-mass of silica on the surface of Ag@SiO2NPs. Transmission electron microscopy (TEM) displayed the spherical shape of nanoparticles and average size of 11 nm for GT-AgNPs and Ag@SiO2NPs. Ag@SiO2NPs demonstrated potent antimicrobial action against S. mutans, with MIC determined as 600 µg/mL, and inhibition of approximately 44% (p < 0.05) of biofilm formation. At the MIC concentrations, both NPs did not exhibit cytotoxicity. CONCLUSION: Ag@SiO2NPs might have a useful application in dental materials. CLINICAL SIGNIFICANCE: The possibility of incorporating antimicrobial properties in restorative materials without compromising esthetics makes the AgNPs@SiO2 NPs promising agents against S. mutans biofilm formation, hence the prevention of dental caries. This represents a great step towards the development of more interactive biomaterials in dentistry to overcome clinical problems.

Development of novel dental restorative composites with dibasic calcium phosphate loaded chitosan fillers.

The incorporation of antimicrobial agents in restorative dental composites has the potential to slow the development of carious lesions. OBJECTIVE: The objectives of the present study were to develop experimental composite resins with chitosan or chitosan loaded with dibasic calcium phosphate anhydrous (DCPA) particles and to demonstrate their antimicrobial potential without loss of mechanical properties or biocompatibility. METHODS: Chitosan and chitosan/DCPA particles were synthetized by the electrospray method. Experimental composites were formulated by adding 0, 0.5, or 1.0 wt% particles into a resin matrix along with 60 wt% barium glass. The degree of conversion and mechanical properties were measured after 1 and 90 days of aging in water after photoactivation. Cytotoxicity and genotoxicity were evaluated using fibroblasts from dental pulp in conditioned medium. The antimicrobial activity against Streptococcus mutans was assessed by crystal violet biofilm assay. RESULTS: The experimental restorative composites were not found to be cytotoxic or genotoxic, with cell viability of 93.1 ± 8.0% (p = 0.328) and 3.0 ± 0.8% micronucleus per group (p = 0.1078), respectively. The antimicrobial results showed that all composites with approximately 20% less biofilm (p < 0.001) relative to the control. No chitosan release was detected from the composites, suggesting direct contact of the bacteria with exposed chitosan particles on the surface was responsible for the observed antimicrobial effect. The addition of the chitosan and chitosan/DCPA submicrometer (<250 nm average diameter) particles to restorative composites did not change the degree of conversion, flexural strength, elastic modulus and fracture toughness compared to the control group after 90 days aging in water. SIGNIFICANCE: It can be concluded that the addition of chitosan or chitosan/DCPA particles in the restorative composites induced antimicrobial activity without compromising the mechanical properties or biocompatibility of the composites.

Influence of BisGMA, TEGDMA, and BisEMA contents on viscosity, conversion, and flexural strength of experimental resins and composites.

Different monomer structures lead to different physical and mechanical properties for both the monomers and the polymers. The objective of this study was to determine the influence of the bisphenylglycidyl dimethacrylate (BisGMA) concentration (33, 50 or 66 mol%) and the co-monomer content [triethylene glycol dimethacrylate (TEGDMA), ethoxylated bisphenol-A dimethacrylate (BisEMA), or both in equal parts] on viscosity (eta), degree of conversion (DC), and flexural strength (FS). Eta was measured using a viscometer, DC was obtained by Fourier transfer Raman (FT-Raman) spectroscopy, and FS was determined by three-point bending. At 50 and 66% BisGMA, increases in eta were observed following the partial and total substitution of TEGDMA by BisEMA. For 33% BisGMA, eta increased significantly only when no TEGDMA was present. The DC was influenced by BisGMA content and co-monomer type. Mixtures containing 66% BisGMA showed a lower DC compared with mixtures containing other concentrations of BisGMA. The BisEMA mixtures had a lower DC compared with the TEGDMA mixtures. The FS was influenced by co-monomer content only. BisEMA mixtures presented a statistically lower FS, followed by TEGDMA + BisEMA mixtures, and then by TEGDMA mixtures. Partial or total replacement of TEGDMA by BisEMA increased eta, which was associated with the observed decreases in DC and FS. Although the BisGMA content influenced the DC, it did not affect the FS results.

Clinical performance and chemical-physical properties of bulk fill composites resin -a systematic review and meta-analysis.

OBJECTIVES: The objective of this study was to perform a meta-analysis of clinical and laboratory studies to compare the performance of bulk-fill and conventional composite resins in terms of polymerization shrinkage, polymerization stress, cusp deflection, marginal quality, degree of conversion, microhardness, flexural strength, fracture strength and clinical performance. DATA: One hundred three articles were included in this study, and the Peto method was used to compare the bulk-fill and conventional composites using the RevMan software. SOURCES: Searches were performed in the PubMed and Scopus databases. STUDY SELECTION: Laboratory studies and randomized clinical trials comparing one of the previous detailed outcomes between bulk-fill and control composites were included. CONCLUSIONS: The bulk-fill composite resins showed less shrinkage, polymerization stress, cusp deflection and microhardness than conventional composites, while both materials presented a similar marginal quality, flexural strength and fracture strength. Also, bulk-fill materials with regular viscosity showed similar shrinkage. The conversion of bulk-fill materials with flowable consistency were similar to conventional composite resins with a thickness of up to 2mm and greater than conventional composites with a thickness greater than 2mm. Despite these in vitro differences, the clinical performance of bulk-fill and conventional composite resins was similar in randomized clinical trials, with one to ten years of follow up. In conclusion, the bulk-fill materials show better or similar performance to the conventional materials in clinical trials and laboratory studies in terms of volumetric shrinkage, polymerization stress, cusps deflection and marginal quality, with the only exception being the lower level of microhardness observed for bulk-fill composites with thickness up to 2mm.

Polymerization stress of resin composites as a function of system compliance.

OBJECTIVES: Evaluate the effect of testing system compliance on polymerization stress and stress distribution of composites. METHODS: Composites tested were Filtek Z250 (FZ), Herculite (HL), Tetric Ceram (TC), Helio Fill-AP (HF) and Heliomolar (HM). Stress was determined in 1-mm thick specimens, inserted between two rods of either poly(methyl methacrylate), PMMA, or glass. Experimental nominal stress (sigmaexp) was calculated by dividing the maximum force recorded 5 min after photoactivation by the cross-sectional area of the rod. Composites' elastic modulus (E) was obtained by three-point bending. Data were submitted to one-way ANOVA/Tukey's test (alpha=0.05). Stress distribution on longitudinal (sigmay) and transverse (sigmax) axes of models representing the composites with the highest and lowest E (FZ and HM, respectively) were evaluated by finite element analysis (FEA). RESULTS: sigmaexp ranged from 5.5 to 8.8 MPa in glass and from 2.6 to 3.4 MPa in PMMA. Composite ranking was not identical in both substrates, since FZ showed sigmaexp statistically higher than HM in glass, while in PMMA FZ showed values similar to the other composites. A strong correlation was found between stress reduction (%) from glass to PMMA and composite's E (r2=0.946). FEA revealed that system compliance was influenced by the composite (FZ led to higher compliance than HM). sigmax distribution was similar in both substrates, while sigmay distribution showed larger areas of compressive stresses in specimens built on PMMA. SIGNIFICANCE: sigmaexp determined in PMMA was 53-68% lower than in glass. Composite ranking varied slightly due to differences in substrates' longitudinal and transverse deformation.

Tooth color changes and sensitivity in patients undergoing dental bleaching with 10% hydrogen peroxide using customized trays or strips: a randomized clinical trial.

BACKGROUND: This paper aimed to compare the tooth color changes and sensitivity in patients undergoing dental bleaching with 10% hydrogen peroxide using customized trays or strips as delivering systems. METHODS: A total of 50 patients aged between 18-30 years old were assigned into two groups (N.=25) according to the bleaching treatment: tray (TB) or strips (SB). For both techniques, the patients underwent a 30-minute application of 10% hydrogen peroxide twice a day for seven days. Tooth color was evaluated before, 3 and 7 days of treatment, and 14 days after bleaching using a tooth color shade guide (VITA® shade). Tooth sensitivity was assessed using the Visual Analogue Scale (VAS). The values obtained from the color changes and tooth sensitivity were statistically analyzed (α=5%). RESULTS: For both groups, there was a significant difference on the tooth color before and after bleaching (P<0.001), although there was no significant difference between them (P=0.4215). The SB group exhibited a lower frequency of sensitivity (50.2%) compared to the TB group (70.2%) (P<0.001). However, the highest number of individuals reporting score 1 of sensitivity was found in the SB group (37.3%) compared to the TB group (20.9%) (P<0.001). For the other scores, there were no differences between the SB and TB groups, with results of 9.8% and 8.4% for score 2 (P=0.744) and 2.7% and 0.5% for score 3 (P=0.122). CONCLUSIONS: The bleaching effect of 10% hydrogen peroxide is not influenced by the delivering system (tray or strips). Even though the technique with strips was associated to a lower frequency of dental sensitivity, the peak level of pain was greater when compared to the technique using trays.

Retrospective study on midfacial advancement in syndromic craniosynostosis: case series.

AIMS: The aim of this study was to evaluate elastic distraction surgical procedures performed on patients with syndromic craniosynostosis using cephalometric analyses. METHODS: Eleven patients who underwent surgical midfacial advancement were divided into three groups: G1 - monobloc frontofacial; G2 - Le Fort III; and G3 - high-level Le Fort I. The cephalometric analyses were manually created through cephalometric radiographs of each patient: T1 - preoperative; T2 - 6 months postoperatively; and T3 - 12 months postoperatively. The cephalometric landmark points were A and O. The distances between preoperative and postoperative tracings were measured. RESULTS: Point A advanced with no significant relapse 12 months after surgery. Point O advanced with a significant relapse rate of 28.5% postoperatively (p = 0.019). The vertical movement of points A and O increased by 40.6% (p = 0.033) and 38.8% (p = 0.032), respectively. There were no significant statistical differences between the assessed surgical techniques and syndromes with regard to midfacial advancement. CONCLUSION: Point O has presented statistically significant relapse only in horizontal movement after 12 months. The cephalometric analysis performed in the present study only suggested no differences between the studied surgical techniques and syndromes with regard to midfacial advancement in syndromic craniosynostosis.

Knowledge of primary care professionals about fluoride topics.

BACKGROUND: Scientific evidence on the benefits of fluoride was responsible for an important change in dental practice. Individual and collective actions have been planned to impact the epidemiology of oral health. However, questions around this topic persist, making discussions and researches still necessary. In this regard, the aim of this study was to verify the fluoride-related knowledge of pediatricians (PP) and dentists (DS) working in primary care, comparing related aspects such as its multiple sources of intake and dental fluorosis. METHODS: A group of PP and DS answered as self-administered questionnaire related to fluoride knowledge. PP group presented a lower level of adherence (34%) in comparison to the DS group (70%). RESULTS: Fluoride-related topics were learnt at undergraduate courses by 95,95% of dentists and 38.46% of pediatricians. Ninety-two per cent of DS and 78.57% of PP claimed to know the clinical aspects of dental fluorosis. Pediatricians tend to indicate the use of fluoridated dentifrices at any age but advise less about the right amount to be placed on the toothbrush in comparison to DS. CONCLUSIONS: Dentists and pediatricians presented limited fluoride-related knowledge. Continued education/training is encouraged and necessary at this level in order to deliver the benefits of fluoride use to populations.

A comparative study of bulk-fill composites: degree of conversion, post-gel shrinkage and cytotoxicity.

Bulk-fill composites are claimed to be restorative materials used in deep preparations and effectively photoactivated in layers up to 4 mm. The aim of the present study was to evaluate the degree of conversion, post-gel volumetric shrinkage, and cytotoxicity of six bulk-fill and two conventional composites. Degree of conversion was determined by FTIR spectroscopy; post-gel volumetric shrinkage was determined using the strain gauge method; and cytotoxicity in human fibroblasts was evaluated indirectly by the MTT assay. Data were subjected to one-way ANOVA/Tukey's test (α = 0.05). All materials, including bulk-fill and conventional composites, were classified as non-toxic, with cell viability higher than 70%. Bulk-fill composites exhibited volumetric shrinkage similar to or lower (1.4 to 0.4%) than that of conventional composites (1.7-2.1%). However, only four of the bulk-fill composites were able to sustain a homogeneous conversion at the 4-mm depth. Despite their non-toxicity and shrinkage similar to that of conventional materials, not all commercial bulk-fill materials were able to maintain a conversion as high as 80% of the superficial layer, at the 4-mm depth, indicating some failure in the bulk-fill design of some commercial brands. Therefore, the use of bulk-fill materials in dental practice is advantageous, but special attention should be given to the selection and correct use of the materials.