Evaluation of reservoirs in bleaching trays for at-home bleaching: a split-mouth single-blind randomized controlled equivalence trial

Objectives: This randomized, split-mouth, single-blinded trial assessed whether the use of reservoirs in at-home bleaching trays is equivalent to non-reservoir trays. Our choice of an equivalence trial was based on the expectation that a non-reservoir tray is sufficient to produce a color change. Secondary outcomes such as tooth sensitivity (TS) and gingival irritation (GI) were also assessed. Methodology: Forty-six patients were selected with canines shade A2 or darker. In half of the patient’s arch, bleaching trays were made with reservoirs and the other half, without reservoirs. At-home bleaching was performed with carbamide peroxide (CP) 10% (3 h daily; 21 days). Color change was evaluated with a digital spectrophotometer (ΔE, ΔE00, and Whiteness Index) and shade guide units (ΔSGU) at baseline, during and one-month post-bleaching. TS and GI were assessed with a numeric scale (NRS) and a visual analog scale (VAS). Results: After one month, the equivalence of reservoir and non-reservoir groups were observed in all color instruments (p>0.05). Fifteen and sixteen patients presented pain (absolute risk: 33% and 35%, 95%, confidence interval (CI) 21-46% and 23-49%) in the reservoir and non-reservoir side, respectively. The odds ratio for pain was 0.8 (95%CI 0.2-3.0) and the p-value was non-significant (p=1.0). TS intensity was similar between both groups in any of the pain scales (p>0.05). No difference in the GI was observed (p>0.05). Conclusions: The protocol with reservoirs is equivalent in color change to the non-reservoir, although no superiority of the latter was observed in terms of reduced TS and GI with at-home 10% carbamide peroxide bleaching. Clinical Relevance: The presence of reservoirs in a bleaching tray did not improve color change or affect tooth sensitivity and gingival irritation

Evaluation of the color stability of different temporary restorative materials

This study aimed to evaluate the color stability of different temporary restorative materials in contact with staining solutions, as well as to verify which one presents the highest resistance to staining. In this laboratory study, five types of temporary restorative materials were evaluated: self-curing acrylic resin, bis-acrylic resin, light-curing acrylic resin, CAD/CAM machinable, and 3D printed resin. Thirty samples of each material were produced in a circular mold measuring 10 mm diameter and 2 mm thickness. The materials were divided into subgroups (n=10) and immersed in solutions: Coffee, Coca-cola®, and distilled water (control). Color measurements were carried out at baseline, 1, 7, and 14 days using a digital spectrophotometer and the color parameters were calculated according to the CIEDE00 system. The color change data were subjected to two-way ANOVA (temporary material vs time) and post-hoc Tukey test (α = 0.05). The materials showed a color change only comparing baseline vs. one day, according to acceptability standard ΔE00 > 1.8. Thus, we concluded that there was a difference in color stability already on the first day of immersion. In addition, the coffee solution showed the highest color variation when compared to the other solutions. Clinical applicability: Temporary restorations are widely used in prosthetic treatments and can remain in the mouth for a considerable period. They are responsible for aesthetic and function maintenance along the rehabilitation process. In addition, they provide data for the definitive prosthesis and should assure comfort and confidence to the patient.  Thus, it is necessary that these materials are resistant and present such color stability that does not compromise the aesthetics during the treatment phase

In-office dental bleaching in adolescents using 6% hydrogen peroxide with different application tips: randomized clinical trial

Despite the availability of in-office bleaching gels with a 6% concentration of hydrogen peroxide (HP), these gels have not been evaluated in younger patients. They are commercially available with a tip, associated or not with a brush, where the tip with a brush spreads the gel over the entire surface to have a smaller thickness (thin layer) since the manufacturers indicate the application of a thin layer of gel. Objective: This randomized, split-mouth, double-blind clinical trial evaluated the efficacy of in-office bleaching with 6% HP in adolescents using different application tips, as well tooth sensitivity (TS) and aesthetic self-perception. Methodology: Sixty participants were randomized for 6% HP self-mixing bleaching gel tip design: without brush and with brush. In-office bleaching was performed in 3 sessions of 50 minutes. Color change was evaluated using a digital spectrophotometer (ΔE ab , ΔE 00 , and ΔWI D ) and color guide (ΔSGU), the absolute risk and intensity of TS with a visual analogue scale and aesthetic self-perception with the oral aesthetic scale (a=0.05). Results: The groups achieved similar bleaching regardless of the application tip (p>0.05). However, only for ΔWI D , a significant mean difference (MD) was observed in the third week (MD 2.3; 95% CI 1.2 to 3.3; p < 0.001) and at one month (MD 1.6; 95% CI 0.6 to 2.6; p < 0.03) favoring the tip without brush. Regarding TS, 45% in the tip-without-brush group and 33% in the tip-with-brush group reported TS (odds ratio 0.61; 95% CI 0.29 to 1.28; p<0.02), with low TS intensity (MD 0.05; 95% CI -0.06 to 0.17; p>0.36). All patients reported improved aesthetic self-perception after bleaching (MD -1.3; 95% -1.8 to -0.9; p<0.001). Conclusions: Regardless of the tip used bleaching with 6% HP achieved a bleaching efficacy and improved the aesthetic self-perception. However, a lower risk of TS for application using the tip with brush was observed. &nbsp

Análise da capacidade de vedamento bacteriano na interface entre implante e pilar em dois sistemas de junção / Analysis of bacterial sealing capacity at the interface between implants and abutments in two joining systems

Avaliar in vitro a contaminação bacteriana na interface implante-pilar em implantes dentários com conexões dos tipos hexágono interno e hexágono externo, por meio de análise microbiológica. Foram analisados 24 conjuntos (n = 12), os quais foram divididos nos seguintes grupos: conexão hexágono interno (HI); conexão hexágono externo (HE); controle positivo (CP) e controle negativo (CN). Todos os grupos foram contaminados no interior do implante com Escherichia coli, exceto o grupo CN. Em seguida, os pilares foram conectados, aplicado torque de 20 N e os conjuntos foram imersos em uma solução de caldo Brain Heart Infusion (BHI), onde foram mantidos durante 14 dias. Os conjuntos foram desconectados por contra torque e porções do caldo de cultura foram coletadas e plaqueadas em Ágar BHI por 24 horas, para observar a formação das unidades formadoras de colônias (CFUs). Depois, foi realizada a coleta de uma porção das CFUs para esfregaço e coloração de Gram. Após os 14 dias, houve turbidez do meio e presença de depósitos em 6/11 tubos de ensaio do hexágono interno e 5/11 para hexágono externo, não havendo diferença estatística (p > 0,05) entre os grupos. Foi confirmado o crescimento dos bacilos Gram-negativos, onde foi possível visualizar a presença de Escherichia coli nas placas correspondentes aos tubos de ensaio que apresentaram turbidez anteriormente. Os resultados do presente estudo sugerem que o tipo de implante não beneficia a redução da contaminação bacteriana através da conexão implante-pilar

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

Abstract 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