Effect of gingival barrier brands on operator perception, cervical adaptation, and patient comfort during in-office tooth bleaching: a randomized clinical trial.

BACKGROUND: Light-cured resins are widely used as gingival barriers to protect the gums from highly concentrated peroxides used in tooth bleaching. The impact of barrier brand on clinical outcomes is typically considered negligible. However, there is limited evidence on the effects of different brands on operator experience, barrier adaptation, and patient comfort. OBJECTIVE: This clinical trial assessed the impact of four commercial gingival barrier brands (Opaldam, Topdam, Lysadam, and Maxdam) on operator perception, adaptation quality, and patient comfort. METHODS: Twenty-one undergraduate students placed gingival barriers in a randomized sequence using blinded syringes. Photographs of the barriers were taken from frontal and incisal perspectives. After bleaching procedures, operators rated handling features and safety using Likert scale forms. Two experienced evaluators independently assessed barrier adaptation quality on a scale from 1 (perfect) to 5 (unacceptable). The absolute risk of barrier-induced discomfort was recorded. Data were analyzed using Friedman and Chi-square tests (α = 0.05). RESULTS: Opaldam and Topdam received the highest scores in most handling features, except for removal, which was similar among all brands. No significant difference was observed in barrier adaptation quality between the evaluated brands. Discomforts were mainly reported in the upper dental arch, with Maxdam having the highest absolute risk (35% for this arch and 24% overall). CONCLUSIONS: This study suggests that gingival barrier brands can influence operator perception and patient comfort. Opaldam and Topdam were preferred by operators, but all brands demonstrated comparable adaptation quality. CLINICAL TRIAL REGISTRATION: The study was nested in a randomized clinical trial registered in the Brazilian Clinical Trials Registry under identification number RBR-9gtr9sc.

Influence of a gray background and the illuminant on tooth shade selection.

STATEMENT OF PROBLEM: Visual shade selection in dentistry may be influenced by factors that include the background color and the illuminant. PURPOSE: The purpose of this clinical study was to evaluate the influence of using a gray background and a light-correcting device on visual shade selection. MATERIAL AND METHODS: Two experienced clinicians assessed the incisor color of 30 volunteers using the VITA 3D-MASTER shade guide. Visual analyses were carried out using or not (control) a gray background, with and without (control) a light-correcting device (Smile Lite). Furthermore, the use of a polarizing filter was evaluated. Data from a clinical spectrophotometer were defined as the standard instrumental analysis. The agreement and the similarity (based on the whitening indexes of tabs) were evaluated between instrumental and visual analyses. Statistical testing was conducted through ordinal logistic regression and repeated-measures ANOVA. The Shapiro-Wilk test was used to confirm the data distribution, and homogeneity of variance was assessed with the Levene test (α=.05) RESULTS: The use of Smile Lite resulted in lighter tabs than indicated by the instrumental analysis, and the opposite was observed in its absence. The polarizing filter did not affect the results (P>.05). For similarity, the illuminant improved the results (P<.001). The gray background reduced the differences between visual and instrumental analysis only in the absence of the Smile Lite (P<.001). CONCLUSIONS: The color similarity between visual and instrumental analysis improved with the use of a light-correcting device with or without a polarization filter. A gray background was useful only without the light-correcting device.

Effectiveness of Supportive Care in the Prevention of Peri-implant Diseases in Brånemark Protocol Rehabilitations: A Retrospective Cohort Study.

This retrospective cohort study aimed to evaluate the efficiency of supportive periodontal treatment (SPT) on peri-implant disease prevention. A total of 63 rehabilitated patients with 504 implants were selected with both maxillary and mandibular Brånemark-type protocols (all-on-four system) placed between 2004 and 2014 in a private practice with 5 to 15 years of follow-up. Study participants were divided into those who adhered to SPT with regular intervals of two or more times a year (Group 1) and those with irregular intervals with more than 1 year without attending SPT (Group 2). The implants placed were evaluated clinically and radiographically to assess peri-implant diseases. The prevalence of mucositis and peri-implantitis in the total population was 64.7% (326 implants) and 3.7% (19 implants), respectively. Group 2 had higher rates of mucositis (181 implants) and peri-implantitis (16 implants) than Group 1 (145 and 3 implants, respectively) (P < .05). The odds ratio for peri-implantitis in Group 2 was 7.1. The results suggest that patients who regularly received SPT had lower chances of developing peri-implant diseases.

Alternative treatment to orthognatic surgery by the application of digital smile planning.

Through the use of the application of a mathematical proportion and a digital golden ratio compass associated with computer software, Digital Smile Planning (DSP) can assist clinicians to achieve the fundamentals of esthetic treatment. The present clinical report describes the application of this technique to propose an alternative and more conservative treatment for a patient who refused the option of orthognathic surgery. To address the diagnosis of a gingival smile with vertical maxillary excess, the alternative treatment comprised crown lengthening surgery, ceramic veneers on the maxillary teeth, and the application of botulinum toxin to reduce lip hyperactivity. Considering the successful resolution of the patient's situation from the perspective of both the dentist and the patient, the application of DSP was considered to be useful to achieve predictable harmony between the face and the dental structures.

Silane content influences physicochemical properties in nanostructured model composites.

OBJECTIVE: To determine the effect of organosilane content on the physicochemical properties of model composites formulated with nano-sized fillers. METHODS: Model composites were formulated with dimethacrylate-based monomers, a photoinitiator/co-initiator system and silicon dioxide nano-sized fillers treated with different amounts of 3-methacryloxypropyltrimethoxysilane (MPTS): 1.0 (G1%), 2.0 (G2%), 5.0 (G5%), 7.5 (G7.5%) and 10 (G10%) wt.% relative to SiO2. Non-silanized fillers (G0%) were used in the control group. Degree of conversion (DC) was assessed by Fourier-transformed infrared spectroscopy (ATR-FTIR). Knoop hardness (KHN) and elastic modulus were determined before and after water storage for 4 months. Water sorption (Wsp) and solubility (Wsl) were calculated by successive mass determinations in analytical balance. Surface gloss and roughness were characterized before and after toothbrushing simulation. RESULTS: With the exception of those fillers treated with 1% MPTS, DC was not dependent on the silane content. Within the silanized groups, G1% showed the lowest initial and final KHN, without statistical difference from G0%. The elastic modulus was not affected by the silane content, regardless of the storage condition, but those groups formulated with at least 5% silane presented improved values after storage. Silane content did not affect the WSl, but affected Wsp, in which those groups formulated with at least 2 wt.% of MPTS produced a more resistant material than G0%. The use of treated particles with at least 2 wt.% of silane was able to produce materials that did not change their gloss after the brushing process. Additionally, these materials presented lower surface roughness than G0% after the brushing process (p < 0.05). SIGNIFICANCE: The concentration of MPTS affected the physicochemical properties of nano-filled composites. Therefore, 2 wt.% of silane was the optimized quantity to produce materials resistant to degradation, both in bulk and surface properties.

Thiourethane-functionalized fillers: biological properties and degradation resistance

Abstract This study determined the effect of thiourethane-functionalized fillers (TU) on the antimicrobial properties, cytotoxicity, degree of conversion (DC), water sorption (Wsp) and solubility (Wsl) of experimental composites. TU-modified fillers were added at different ratios in experimental composites: 0 (Control-TU0), 25% (TU25), 50% (TU50), 75% (TU75) and 100wt% (TU100). The antimicrobial properties were detected through the exhaustion test and counting of Streptococus mutans colonies for biofilm formation. Cytotoxicity to human gingival fibroblasts was evaluated in three different parameters: XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide), NRU (Neutral Red Uptake assay) and CVDE (Crystal Violet Dye Exclusion test)) at the same cells. ELISA was used to measure the IL-6 and b-FGF biomarkers. DC was determined by Fourier-transformed infrared spectroscopy, while Wsp and Wsl by mass variations. Inhibitory capacity of biofilm formation was not observed for any material. All groups presented at least 70% of cell survival within the observed periods (24h and 7 days). Positive control (toxic) had high IL-6 values and low b-FGF values. No significant variations in DC, Wsp, and Wsl were observed among the experimental groups. The use of thiourethane did not present antimicrobial and cytotoxic activity and the tested materials presented equivalent properties to those conventionally used in dentistry.

Thiourethane-functionalized fillers: biological properties and degradation resistance.

This study determined the effect of thiourethane-functionalized fillers (TU) on the antimicrobial properties, cytotoxicity, degree of conversion (DC), water sorption (Wsp) and solubility (Wsl) of experimental composites. TU-modified fillers were added at different ratios in experimental composites: 0 (Control-TU0), 25% (TU25), 50% (TU50), 75% (TU75) and 100wt% (TU100). The antimicrobial properties were detected through the exhaustion test and counting of Streptococus mutans colonies for biofilm formation. Cytotoxicity to human gingival fibroblasts was evaluated in three different parameters: XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide), NRU (Neutral Red Uptake assay) and CVDE (Crystal Violet Dye Exclusion test)) at the same cells. ELISA was used to measure the IL-6 and b-FGF biomarkers. DC was determined by Fourier-transformed infrared spectroscopy, while Wsp and Wsl by mass variations. Inhibitory capacity of biofilm formation was not observed for any material. All groups presented at least 70% of cell survival within the observed periods (24h and 7 days). Positive control (toxic) had high IL-6 values and low b-FGF values. No significant variations in DC, Wsp, and Wsl were observed among the experimental groups. The use of thiourethane did not present antimicrobial and cytotoxic activity and the tested materials presented equivalent properties to those conventionally used in dentistry.

O uso do gel de glicerina melhora a estabilidade de cor de resinas compostas? / Does the use of glycerin gel improve the color stability of composite resins?

Introdução: A camada superficial de resina composta não polimerizada, em função da presença do oxigênio, ocasiona problemas clínicos, como alteração de cor por absorção de pigmentos. Objetivo: Determinar o efeito de diferentes técnicas usadas no controle da formação da camada de dispersão sobre as propriedades ópticas de uma resina composta comercial. Material e método: Espécimes foram produzidos com a resina composta Estelite Sigma. A fotoativação foi conduzida com uma fonte de luz LED Bluephase G2 (1.200 mW/cm2 por 40 s). Os grupos foram determinados em função de três técnicas distintas: 1) sem tratamento (controle); 2) fotoativação com gel de glicerina; 3) polimento com lixa abrasiva após a fotoativação. A estabilidade de cor (ΔE) e o parâmetro de translucidez foram determinados pelo método de espectroscopia de reflectância (Easyshade Compac, Vita) empregando o parâmetro CIELab. As análises foram realizadas imediatamente após a fotoativação e repetidas após 7 dias de armazenamento em água ou em café. Os resultados foram submetidos à análise de variância e ao teste de Tukey (α = 0,05). Resultado: Não houve diferença para ΔE nos grupos envelhecidos em água. Quando armazenados em café, o grupo controle apresentou o maior valor de ΔE, enquanto o grupo polido gerou a menor alteração de cor. A aplicação do gel de glicerina produziu resultados intermediários. O parâmetro de translucidez não foi afetado pelos tratamentos testados. Conclusão: O uso do gel de glicerina minimiza a alteração de cor nas regiões de difícil acesso aos instrumentos de acabamento e de polimento.

Introduction: The resin composite superficial layer not polymerized due to the presence of oxygen leads to clinical problems as color alteration by the absorption of pigments. Objective: Evaluate the effect of different techniques to control the formation of the composite resin dispersion layer on the optical properties of a commercial composite. Material and method Resin composite Estelite Sigma specimens were made. The specimens were light-cured with the LED Bluephase G2 device (1200 mW/cm2 - 40 s). The groups were determined according to three different techniques: 1) no treatment (control); 2) light-curing through a glycerin gel layer on the surface; 3) polishing with abrasive discs after light-curing. The color stability (ΔE) and the translucency parameter were determined by the spectroscopy method (Easyshade Compact Vita) as a function of the CIELab parameter. The analyzes were performed immediately after photoactivation and repeated after 7 days of storage in water or 7 days in coffee. The results were submitted to ANOVA and Tukey test (α = 0.05). Result : No difference was found for ΔE in groups aged in water. When stored in coffee, the control group had the highest value of ΔE while the polished group generated the lowest color change. The glycerin gel groups promoted intermediated results. The translucency parameter was not affected by the treatments tested. Conclusion: The glycerin-based gel layer minimizes the color change in those regions that the finishing and polishing instruments are difficult to access.

Clinical Time Required and Internal Adaptation in Cavities restored with Bulk-fill Composites.

AIM: The aim of this study was to compare the restorative time required and the internal adaptation after thermomechanical aging of class I restorations using either the conventional incremental technique or bulk-fill technique. MATERIALS AND METHODS: Cavities (Class I) were prepared on the occlusal surface of human third molars. 40 teeth were divided into four experimental groups according to the restorative technique (n = 10): G1 = 3 mm increment of Surefill SDR Flow + 1 mm Filtek P60; G2 = 3 mm increment of Filtek Bulk-Fill + 1 mm Filtek P60; G3 = Filtek P60 inserted with incremental technique; G4 = 3 mm increment of Filtek Z350 Flow XT + 1 mm increment of Filtek P60. The required restorative clinical time for each technique was marked. Specimens were submitted to thermomechanical loading (20,000 mechanical cycles-80 N/thermal cycling-5/55°C for 30 seconds). After, samples were sectioned, ratio of internal gaps to interface length (%) was recorded using dye-staining-gap technique. Data were submitted to analysis of variance (ANOVA) and Tukey's test (95% significance). RESULTS: There was no significant difference in gap formation and none of the groups was completely gap-free. However, a significant reduction on required restorative clinical time was observed for G1 (167 ± 7 seconds), G2 (169 ± 4 seconds), and G4 (169 ± 8 seconds) when compared with G3 (204 ± 8 seconds). CONCLUSION: No significant difference in gap formation was found among bulk-fill and conventional incremental restorative technique tested; however, the use of a bulk-fill composite reduced 20% of the required restorative clinical time. CLINICAL SIGNIFICANCE: None of the restorative techniques applied were able to prevent internal gap formation. The use of bulk-fill composite reduced the required clinical time to perform class I restorations.

Antibiofilm properties of model composites containing quaternary ammonium methacrylates after surface texture modification.

OBJECTIVE: Investigate antimicrobial properties and surface texture of model composites with different concentration and alkyl chain length of quaternary ammonium monomers (QAS). METHODS: Monomers derived from QAS salts with alkyl chain lengths of 12 carbons ((dimethylaminododecyl methacrylate) DMADDM) and 16 carbons (dimethylaminohexadecyl methacrylate-DMAHDM) were obtained from the reactions of their respective organo-halides with the tertiary amine 2-(dimethylamino)ethyl methacrylate (DMAEMA). DMADDM and DMAHDM were incorporated into model composite in concentrations of 5 or 10%, resulting the following groups: G12.5 (DMADDM 5%), G12.10 (DMADDM 10%), G16.5 (DMAHDM 5%), G16.10 (DMAHDM 10%) and GC (control). Biofilm viability, lactic acid production and surface roughness were analysed 24h after samples preparation (initial), repeated after toothbrush abrasion and after polishing simulation. Data were submitted to ANOVA and Tukey's test (p≤0.05). RESULTS: The longer the molecular chain size of QAS and the higher its concentration (G16.10), the lower was the viability and the production of lactic acid by the biofilm. No differences were detected in initial roughness' measurements among groups. However, after abrasion, there was an increase of biofilm viability and lactic acid production. Composites containing QAS presented rougher surfaces compared to the CG. After polishing, biofilm viability and surface roughness were statistically similar for all groups. Nevertheless, DMAHDM at 10% showed reduction in lactic acid production. SIGNIFICANCE: Chain length and concentration of QAS influenced biofilm development and production of lactic acid. Longer chains and higher concentrations of QAS promoted better antimicrobial properties. Changes in surface texture caused by abrasion, decreased antibiofilm properties.

Baixo nível de ansiedade dos pacientes atendidos no curso de odontologia de uma instituição de ensino superior / Low level of anxiety of patients treated in a dentistry course of a higher education institution

Apesar de benéfico, o tratamento odontológico pode gerar ansiedade para o paciente e para o cirurgião-dentista. Se verificada além de um limite aceitável, a ansiedade pode impedir que o paciente se submeta ao tratamento, comprometendo sua qualidade de vida. Diante da relevância do assunto, objetivou-se avaliar o perfil dos pa¬cientes atendidos nas clínicas odontológicas de uma instituição de ensino e seu nível de ansiedade diante do tratamento odontológico. Foram entrevistados 133 pacientes em tratamento nas clínicas integradas e do mestrado da Universidade Veiga de Almeida, entre março e outubro de 2015. Os pacientes responderam a um questionário com dados socioeconômicos e questões específicas para a identificação do grau de ansiedade ao tratamento odontológico, utilizando a escala DAS (Dental Anxiety Scale). A amostra foi composta de maneira equivalente por homens e mulheres, a maioria tinha mais que 45 anos (51,1%), com renda de até 5 salários mínimos (66,9%) e com grau de instrução superior (56,4%). Embora 88,7% tenham relatado algum nível de an¬siedade, este foi considerado baixo. Não houve diferença estatística entre o grau de ansiedade de homens e mul¬heres (p=0,458). Não se observou associação entre idade, gênero, renda, grau de instrução, frequência de ida ao dentista e o nível de ansiedade (p>0,05). Houve uma associação significativa (p=0,015) entre procedimentos que incomodam durante a consulta, como a alta rotação e a anestesia, e os níveis de ansiedade observados. Pode-se concluir que o nível de ansiedade dos pacientes atendidos foi considerado baixo; entretanto mostrou uma associação positiva com procedimentos como a alta rotação e a anestesia

Despite the fact that it is beneficial, dental treatment can cause anxiety for the patient and the dentist. If verified beyond an acceptable limit, anxiety can prevent the patient to undergo treatment, compromising his quality of life. The aim of this study was to evaluate the profile of patients treated in dental clinics of a teaching institution and their integrated and master's degree clinics from University Veiga de Almeida were interviewed between March and October 2015. The patients answered a questionnaire with socio-economic data and questions to identify the degree of anxiety to dental treatment, using the scale DAS (Dental Anxiety Scale). The sample in¬cluded male (50.4%) aged more than 45 years (51.1%), with income of up to 5 minimum wages (66.9%) and higher level of education (56.4%). Although 88.7% have reported some level of anxiety, this was considered low. There was no statistical difference between the degree of anxiety of men and women (p=0.458). No as¬sociation was found between age, gender, income, level of education, frequency of dental visits and the level of anxiety (p> 0.05). There was a significant association (p = 0.015) between procedures that bother during dental visit, such as high-speed air turbine and anesthesia, and observed anxiety levels. It can be concluded that the level of anxiety of patients was considered low; however, it showed a positive association with procedures such as high-speed air turbine and anesthesia

Conhecimento de cirurgiões-dentistas sobre o diagnóstico e o tratamento de lesões cervicais não cariosas: um estudo piloto em rede colaborativa

Objetivo: identificar o perfil de formação e atendimento de cirurgiões dentistas (CDs) e procurar compreender qual a conduta prestada por esses profissionais em relação ao diagnóstico e ao tratamento das lesões cervicais não cariosas (LCNCs). Sujeitos e método: um questionário foi disponibilizado e enviado para CDs com o cadastro atualizado na base de dados do Conselho Regional de Odontologia do Rio de Janeiro. Os resultados foram analisados de forma descritiva e o teste de Qi-Quadrado com nível de significância de 5%. Resultados: a maioria dos CDs procura fazer distinção entre as diferentes formas de LCNCs (76,5%), porém não usa método auxiliar (83,2%) e não possui questionário específico (59,7%). Para 40,3% dos CDs, a etiologia das LCNCs é unifatorial ou não soube responder. A maioria faz uso de isolamento relativo (65,6%) e utiliza técnicas de retração/afastamento gengival (83,2%). O sistema adesivo convencional de dois passos (63%) e a resina composta do tipo híbrida/micro-híbrida (52,1%) são os materiais mais utilizados. Com relação à longevidade das restaurações, apenas 17,6% dos CDs acreditam na duração por um período acima de 5 anos. Com relação às associações, houve relação entre a forma de remuneração e o uso/método de isolamento (p = 0,004) e entre a forma de remuneração e o uso de técnicas de retração/afastamento gengival (p = 0,005). Conclusões: os CDs não possuem um protocolo preestabelecido para correto diagnóstico de LCNCs. A forma de remuneração influencia no uso do isolamento para o tratamento restaurador. O sistema adesivo convencional de dois passos é o mais utilizado pelos CDs.

Surface Texture and Optical Properties of Self-Adhering Composite Materials after Toothbrush Abrasion.

UNLABELLED: This study evaluated the surface texture and optical properties of two self-adhering composites and a nanofilled composite before and after toothbrush abrasion. Vertise Flow (Kerr), Fusio Liquid (Pentron Clinical) and Filtek Z350 XT (3M ESPE) composites were divided into 3 groups (n = 6). Disks of 12 mm diameter and 2 mm thick were made. All materials were light-cured with a LED light source for 40 seconds. Analyses of surface roughness, gloss retention and color stability were performed 24 hours after light curing and after 20,000 brushing cycles. Data were analyzed with analysis of variance (ANOVA) and Tukey's test (α = 5%). RESULTS: Tukey's test ascertained that toothbrush abrasion resulted in rougher and matte surfaces for all composites tested. Filtek Z350 presented better gloss retention after abrasion. On surface roughness evaluation, there was no statistical difference between Fusio Liquid Dentin and Filtek Z350 resins (p > 0.05). Vertise Flow resin showed better color stability (ΔE), than the other two materials. CONCLUSION: Nanofilled material presented better gloss retention but it did not produce the best results in aspects related to surface roughness and color stability compared to self-adhering composites. CLINICAL SIGNIFICANCE: A simulation of degradation process by using toothbrush abrasion produced a rougher and matte surface in all composites tested. The surface texture was not only related to filler's amount present in materials, but also with the organic matrix composition of them. The results suggested that the constant development of new materials, seeking for a technical simplification, seems an innovative attraction for dentist's clinical routine, even though larger studies are necessary to promote to everyone a better understanding and improvement of action and effectiveness of this new class of materials.

Influence of hydroxyethyl acrylamide addition to dental adhesive resin.

OBJECTIVE: to determine the physicochemical properties of experimental adhesive resins containing hydroxyethyl acrylamide. METHODS: Three groups of experimental resin were formulated, GHEAA33% (33.3wt% HEAA+66.6wt% BisGMA), GHEAA50% (50wt% HEAA+50wt% BisGMA), and GHEAA-FREE (33.3wt% HEMA+66.6wt% of BisGMA). The polymerization process of each adhesive resin group, as well as for the homopolymers, BisGMA, HEMA, HEAA, HEMA* without EDAB, and HEAA* without EDAB, was characterized through differential scanning calorimetry (DSC). Elution of monomers was evaluated by (1)H NMR. Dynamic mechanical analysis (DMA) was used to collect the glass transition temperature (Tg), the storage modulus (E') and the reticulation degree (ρ). Flexural strength was calculated by three-point bending test with 0.75mm/min. Softening in solvent was calculated through hardness before and after immersion in water or ethanol. RESULTS: GHEAA50%, GHEAA33%, GHEAA-FREE presented higher polymerization rate ( [Formula: see text] , 12.3 and 5.3mmolg(-1)s(-1), respectively) than homopolymers HEMA, HEMA* and HEAA*. Group with HEAA presented higher degree of conversion (GHEAA50%=64.07%>GHEAA33%=55.82%>GHEAA-FREE=49.02%; p=0.008) All groups presented low elution of monomers (p>0.05). The values of E' were higher on GHEAA33% than GHEAA-FREE (p=0.034). Tg and flexural strength values of GHEAA-FREE were higher than acrylamide groups (p=0.022 and p<0.001, respectively). Hardness varied from 27.05 to 34.78 for water and from 63.27 to 68.51 for ethanol with no difference for ρ values. SIGNIFICANCE: The addition of HEAA increased the materials reactivity and, consequently, improved the maximum rate of polymerization, degree of conversion and the storage modulus of experimental adhesive resin.

Do new matrix formulations improve resin composite resistance to degradation processes?

The aim of this study was to determine the degradation resistance of three new formulations-silorane-, Ormocer- and dimer-acid-based materials-and compare them to the traditional dimethacrylate-based materials. One silorane- (Filtek P90, P90), one Ormocer- (Ceram-X, CX), one dimer-acid- (N'Durance, ND) and two dimethacrylate-based (Filtek P60, P60; Tetric Ceram, TC) materials were investigated. Water sorption (Wsp) and solubility (Wsl) were determined after the materials were immersed in water for 28 days. Knoop hardness (KH) was determined before and after 24 h immersion in pure ethanol. The flexural-strength (FS) was determined by the bending test after one-week storage in a dry environment or after one-week immersion in pure ethanol. Data were submitted to analysis of variance (ANOVA) and Tukey's test (95%). The three new formulations showed lower Wsp than the dimethacrylate-based formulation. CX (0.50 ± 0.17%) and ND (0.72 ± 0.19%) exhibited the lowest Wsp, whereas P90 (0.02 ± 0.03%) and P60 (0.04 ± 0.03%) showed the lowest Wsl. All resins showed reduced Knoop hardness number (KHN) after ethanol immersion. P60 presented the lowest decrease in KH value (19 ± 5%). TC (48 ± 3%) and P90 (39 ± 9%) showed the highest KHN decrease after ethanol storage. The FS of CX, ND and TC were affected by ethanol storage. The new formulations did not improve the degradation resistance, as compared with the traditional methacrylate-based materials.

Do new matrix formulations improve resin composite resistance to degradation processes?

The aim of this study was to determine the degradation resistance of three new formulations-silorane-, Ormocer- and dimer-acid-based materials-and compare them to the traditional dimethacrylate-based materials. One silorane- (Filtek P90, P90), one Ormocer- (Ceram-X, CX), one dimer-acid- (N'Durance, ND) and two dimethacrylate-based (Filtek P60, P60; Tetric Ceram, TC) materials were investigated. Water sorption (Wsp) and solubility (Wsl) were determined after the materials were immersed in water for 28 days. Knoop hardness (KH) was determined before and after 24 h immersion in pure ethanol. The flexural-strength (FS) was determined by the bending test after one-week storage in a dry environment or after one-week immersion in pure ethanol. Data were submitted to analysis of variance (ANOVA) and Tukey's test (95%). The three new formulations showed lower Wsp than the dimethacrylate-based formulation. CX (0.50 ± 0.17%) and ND (0.72 ± 0.19%) exhibited the lowest Wsp, whereas P90 (0.02 ± 0.03%) and P60 (0.04 ± 0.03%) showed the lowest Wsl. All resins showed reduced Knoop hardness number (KHN) after ethanol immersion. P60 presented the lowest decrease in KH value (19 ± 5%). TC (48 ± 3%) and P90 (39 ± 9%) showed the highest KHN decrease after ethanol storage. The FS of CX, ND and TC were affected by ethanol storage. The new formulations did not improve the degradation resistance, as compared with the traditional methacrylate-based materials.

Avaliação da abrasividade de escovas dentais com cerdas macias / Abrasion assessment of soft bristle toothbrushes

Uma ampla variedade de escovas dentais está disponível no mercado com diversas indicações clínicas. Entretanto, poucos estudos na literatura avaliam a abrasão de escovas de diferentes marcas sobre as restaurações de resina composta. Objetivo: o presente estudo buscou avaliar a abrasividade de três escovas dentais com cerdas macias: Oral B Indicator Plus®, Colgate Extra Clean® e Dr. Veit Soft® em um compósito restaurador. Materiais e método: discos do compósito (8 mm x 2 mm) Tetric Ceram® foram produzidos e fotoativados com uma fonte de luz LED por 40 segundos cada. Dezoito amostras foram confeccionadas e divididas em três grupos experimentais (n = 6). Foram avaliadas a rugosidade superficial (Ra) e a massa em gramas (g) de cada espécime. Em seguida, os espécimes e as escovas foram posicionados em uma máquina simuladora de escovação (ODEME®, Luzerna, SC, Brasil). Os grupos foram submetidos a ciclos que simularam o uso contínuo das escovas por 3 meses. Para cada amostra, foi preparada uma pasta contendo a proporção em massa 1:2 de água destilada e pasta dental. Após a abrasão, a rugosidade e massa foram novamente mensuradas. As extremidades das cerdas foram observadas em um estereomicroscópio com magnitude de 45x. Os resultados foram submetidos ao teste estatístico de Análise de Variância com medidas repetidas no tempo (5%). Resultados: Não houve diferença estatística em massa para nenhum grupo antes e após abrasão (p = 0,727). No entanto, as escovas Oral B Indicator Plus® e Colgate Extra Clean® produziram superfícies mais rugosas (p = 0,002) quando comparada com Dr. Veit Soft® após abrasão. Conclusão: os resultados mostraram que existe variação no potencial de abrasão de escovas dentais classificadas comercialmente como cerdas macias de diferentes fabricantes.

There is a wide variety of toothbrushes available in the market with various clinical indications. However, there are few studies in literature that assess the abrasion of toothbrushes of different brands on composite resin restorations. Objective: the present study assessed the abrasion of three brands of soft bristles toothbrushes: Oral B Indicator Plus™, Colgate Extra Clean™, and Dr. Veit Soft™ on a restorative composite material. Materials and method: discs of composite material (8 mm x 2 mm) Tetric Ceram™ were produced and light cured with an LED unit for 40 seconds each. A total of 18 samples were made and divided in three experimental groups (n = 6). Superficial roughness (Ra) and mass in grams (g) of each sample were assessed. Then, the samples and toothbrushes were placed in a toothbrushing simulating machine (ODEME™, Luzerna, SC - Brazil). The groups were submitted to cycles simulating the continuous use of toothbrushes for 3 months. A paste containing the proportion in mass 1:2 of distilled water and dental paste was prepared for each sample. After abrasion, roughness and mass were measured again. The ends of the bristles were observed with a stereomicroscope at 45x magnitude. The results were submitted to ANOVA test with repeated measures over time (5%). Results: there was no statistical difference in mass for any group before and after toothbrush abrasion (p = 0.727). However, Oral B Indicator Plus and Colgate Extra Clean toothbrushes produced rougher surfaces (p = 0.002) than Dr. Veit Soft after abrasion. Conclusion: the results showed that there are variations in the potential for abrasion of toothbrushes commercially classified as soft bristles from different manufacturers.

Silanização de partículas de carga de compósitos odontológicos - revisão de literatura / Silanization of filler particles of dental composites - literature review

Objective: this study aimed to perform a literature review to facilitate the understanding regarding the type of silane used, as well as the processes involved in silanization of filler particles of dental composites. Literature review: the silane agent is essential to promote a bond between organic and inorganic phases of dental composites. The topics addressed in this study are: basic formulation of monomers employed in dental composites, filler particles used, the importance of the bonding agent in material composition, as well as the types of MPTS silane (γ - methacryloxypropyltrimethoxysilane), OTMS (n-octyltrimethoxysilane) UDMS (3-[(1,3(2)-dimethacryloyloxypropyl)- 2 (3)-oxycarbonylamido] propyl triethoxysilane), GPS (γ- glycidoxypropyltrimethoxysilane), and ATES (organosilanes alyltriethoxysilane), the effects of its applications and silanization processes. Final considerations: a detailed analysis of silane agents allows the knowledge of the advantages and disadvantages of these materials to lead to the improvement and subsequent development of other bonding agents that are more suitable for use in the oral cavity.

Degradation resistance of ormocer- and dimethacrylate-based matrices with different filler contents.

OBJECTIVES: To investigate the influence of matrix and filler content on degradation resistance of an experimental pure-ormocer and an dimethacrylate-based composite derived from a commercially available material. MATERIALS AND METHODS: A dimethacrylate- Grandio (GR) and a model pure ormocer-based-matrix ORMOCER (ORM) were used. Each material had three different types according to their filler content (% w/w): regular (87% and 86%), flowable (80% and 79%) and fissure sealer (70% and 69%) for GR and ORM respectively. Disc-shaped (1 mm thickness×10 mm diameter) samples were prepared for each material (n=6). Water sorption and solubility tests were adapted from ISO4049. To evaluate porosity, specimens were scanned at a resolution of 19.4 µm and 3D reconstructions were made. The volume ratio of pores in the specimens were calculated and expressed as percentages. The results were submitted to 2-way ANOVA (factors: matrix and filler content) and Tukey post-hoc statistic test (p=0.05). RESULTS: Filler content influenced the water sorption for the ormocer-matrix and the water solubility for the dimethacrylates. ORMOCER regular was a less porous material compared to flowable and sealer formulations. On the other hand, the filler content had no effect on porosity for Grandio. CONCLUSION: Modifications made in the pure ormocer-matrix formulation were not significantly important to produce a more water-stable material compared to the dimethacrylate-matrix composite materials.

Reparos em restaurações de resina composta: revisão de literatura / Repairs in composite resin restorations: a literature review

Objetivo: Este trabalho tem como objetivo apresentar os achados da literatura com relação às indicações do reparo de restaurações, buscando conscientizar o profissional a não substituir algumas restaurações desnecessariamente, discutir os materiais a serem utilizados e técnica empregada, a fim de esclarecer e guiar o clínico na prática diária para desempenhar seu trabalho de maneira metódica e bem sucedida. Revisão de literatura: Mesmo que o dentista desenvolva um trabalho criterioso e tome os devidos cuidados ao realizar uma restauração, elas não duram a vida toda e, por vezes, fracassam num curto período de tempo, frustrando algumas expectativas dos pacientes. Infiltrações, recorrência de cáries, desgaste ou fratura da restauração e eventual fratura do elemento dental são alguns motivos que levam à falha da restauração. Diante dessas situações, alguns profissionais, seja por opção, seja por falta de informação, substituem toda a restauração, muitas vezes causando injúria e agressão desnecessária àquele elemento dental. Considerações finais: O avanço da odontologia adesiva oferece a possibilidade de um tratamento restaurador amplamente conservador, sem a necessidade da remoção total de algumas restaurações. Assim, o reparo pode ser empregado preservando a estrutura dental remanescente.