American journal of dentistry最新文献

Purpose: To evaluate denture cleansing solutions regarding the surface roughness and color stability of two resilient liners with distinct optical characteristics used for the maximum recommended period of use.

Methods: The specimens of each resilient liner, transparent and white, were randomly distributed into groups (n= 15) of a daily 20-minute immersion simulation of 0.25%, 0.5% and 1% sodium hypochlorite (SH) and 4% acetic acid solutions. Surface roughness (Ra) and color stability (ΔE CIELab formula and NBS systems) were measured after 7, 14, 21, 30, 60, 90, 180, and 270 days. The factors of variations analyzed were material, solutions, and time of immersion. Statistical analysis used three-way ANOVA and Tukey tests (Ra), and repeated measure ANOVA (ΔE and NBS systems), P< 0.05.

Results: For Ra analysis, the variations occurred regardless of time and solution, as the white liner showed the greatest changes (P< 0.001). Regarding interactions between solution and time, in the period of 21 days until 270 days, Ra was equivalent for all solutions (P= 0.001). ΔE analysis showed a difference between solutions (P= 0.000) and interaction between time and solution (P= 0.000). For the transparent liner, the greatest changes were found for 1% SH after 60 days, however, at 270 days there was a color change equivalence with 0.5% SH, while 4% acetic acid solution showed intermediate values. For the white liner, 1% SH showed the highest color changes for all evaluated times, and the other evaluated solutions were similar after 270 days. For both resilient liners, 0.25% SH showed the smallest changes for the evaluated properties.

Clinical significance: The changes found were dependent on the concentration of the solution used, as well as the length of exposure to the solution. In addition, the white resilient liner showed to be less susceptible to color changes. For both resilient liners, 0.25% sodium hypochlorite showed the least changes for the evaluated properties.

Purpose: To evaluate the mechanical properties of two brands of bulk-fill resin composites placed in a single increment up to 4 mm thickness via a novel mechanical strength test and provide related explanations.

Methods: Light transmission (LT), translucency parameter (TP), color difference (ΔE), Vickers hardness (HV) of two bulk-fill resin composites (Filtek Bulk Fill Posterior, Tetric N-Ceram Bulk Fill) and two conventional resin composites (Z100, Spectrum TPH) were evaluated. A novel flexural strength (FS) test method was applied for bulk-fill resin composite to determine the FS value of the bottom composites at depths of 1, 2, 3, and 4 mm after 24 hours of aging treatment (3 months water storage and 15,000 thermal cycles). The conventional resin composites were also tested for FS and all the FS results were subjected to Weibull analysis. Degree of conversion (DC) in the bulk-fill resin composites, light-cured at depths of 1, 2, 3, and 4 mm and conventional resin composites at depths of 2 and 4 mm, were assessed by FTIR.

Results: Both bulk-fill resin composites showed higher light transmission and translucency than that of conventional ones at each of the same thicknesses (1, 2, 3, 4 mm), wherein their flexural strength was not affected by depth. The Weibull analysis suggested both bulk-fill resin composites achieved good reliability and structural integrity under each curing thickness. Vickers hardness was affected by the material type and thickness. Bulk-fill resin composites showed a decrease in degree of conversion between 1 mm and 4 mm, but both were over 55%.

Clinical significance: Filtek Bulk Fill Posterior, Tetric N-Ceram Bulk Fill achieved acceptable mechanical properties when cured at depths of up to 4 mm, which was beneficial from their optical and polymerized properties.

Purpose: To analyze the effects of surface pre-reacted glass-ionomer (S-PRG) filler eluate on polymicrobial biofilm metabolism and live bacterial count.

Methods: Biofilm was formed using glass disks 12 mm in diameter and 150 µm in thickness. Stimulated saliva was diluted 50-fold with buffered McBain 2005 and cultured in anaerobic conditions at 37°C for 24 hours in anaerobic conditions (10% CO₂, 10% H₂, 80% N₂) to form the biofilm on the glass disks. Following this, biofilms were treated with (1) sterilized deionized water (control), (2) 0.2% chlorhexidine digluconate (0.2CX), (3) S-PRG eluate diluted to 10% (10% S-PRG)，(4) 20% S-PRG，(5) 40% S-PRG，(6) 80% S-PRG，and (7) S-PRG for 15 minutes (n= 10 per group), and samples were subdivided into two groups for measuring live bacterial count immediately after treatment and after 48 hours of culturing after treatment. The pH of the spent medium collected at the time of culture medium exchange was tested.

Results: Immediately after treatment, the live bacterial count of samples treated with drug solutions was significantly lower than the control (8.2 × 10⁸), and the counts of samples treated with 0.2CX (1.3 × 10⁷) and S-PRG (1.4 × 10⁷) were significantly lower than those treated with diluted S-PRG (4.4 × 10⁷-1.4 x 10⁸). When the medium was measured again after culturing for 48 hours, growth was continually inhibited in all treatment groups and the bacterial count of samples treated with S-PRG (9.2 x 10⁷) was significantly lower than that of samples treated with 0.2CX (1.8 × 10⁸). The pH of spent medium immediately after treatment was significantly higher in groups treated with drug solutions (5.5-6.8) than the controls (4.2), and it was highest in the S-PRG-treated group (6.8). Thereafter, when culturing was continued for 48 hours, the pH of all treated groups decreased; however, the pH of the S-PRG-treated group was significantly higher than groups treated with other drug solutions.

Clinical significance: Surface pre-reacted glass-ionomer (S-PRG) filler eluate not only reduced the live bacterial count of polymicrobial biofilm, but also continuously inhibited the lowering of pH.

Purpose: To compare the amount of abrasion of four whitening toothpastes, two conventional toothpastes, and seven experimental toothpastes with varying concentrations of hydrogen peroxide.

Methods: Bovine dentin specimens were treated with the four whitening toothpastes (containing three different concentrations of hydrogen peroxide: 0.75%, 1.50%, and 2.80%), two conventional toothpastes without hydrogen peroxide, seven experimental toothpastes (concentrations of hydrogen peroxide: 0.75%, 1.50%, 3.0%, 4.50%, 6.0%, 7.50%, and 9.0%), and distilled water. After 10,000 strokes of toothbrushing, the amount of abrasion on the dentin surface was measured with a contactless 3D surface profiler (n= 8). The pH of all solutions, the weight percentages of the particles, and the component of particles in the toothpaste were analyzed. The correlations between the dentin abrasion, pH, and weight percentages of the particles in the toothpastes were investigated.

Results: The amount of abrasion of the two conventional toothpastes were 1.1-3.6 times higher than those of the four whitening toothpastes. Likewise, the pH of the conventional toothpaste was higher than those of the other whitening toothpastes. No significant differences were found among the four whitening toothpastes. The four whitening toothpastes consisted of a relatively lower weight percentage of particles compared to the two conventional toothpastes. A strong positive correlation was observed between the dentin abrasion and the weight percentages of the particles (r= 0.913; P< 0.05). Furthermore, no significant differences in the amount of abrasion were observed between the specimens treated with seven experimental toothpastes and those treated with distilled water.

Clinical significance: The whitening toothpastes containing less than 9% hydrogen peroxide did not seem to harm the dentin surface significantly. These findings can serve as a reference for consumers, patients, and dental professionals.

Purpose: To evaluate efficacy of an anesthetic mucoadhesive film with a polymeric device (PD) in promoting anesthesia compared to conventional local infiltration (LA) in children.

Methods: 50 children aged 6-10 years (both genders) needing similar procedures on homologous teeth on the maxilla were included. The parents and children were asked about perception of dental treatment. The child's heart rate per minute (bpm) and blood pressure were evaluated before and after each anesthetic technique (AT) procedure. Anesthesia efficacy was measured by reporting pain using Wong-Baker Faces Scale. Children's behavior and AT preferences were also evaluated. Paired T-test, chi-square and Wilcoxon test were used for statistical comparisons.

Results: Fear of anesthesia was reported by 50% of caregivers and by 66% of children. No difference was observed in systolic (P= 0.282) and diastolic (P= 0.251) blood pressure, comparing both AT. Difference was observed regarding the child's behavior when the PD was used (P= 0.0028). Evaluating the face scale, 74% of the children selected the "no pain" (face 0) (P< 0.0001) for PD, and 26% for LA. PD was preferred by 86% of children. Only 20% of the PD anesthesia needed to be complemented by LA.

Clinical significance: The polymeric device presented promising results since most children did not report pain and dental procedures could be performed without local infiltration.

Purpose: To evaluate the clinical performance of VisCalor and SonicFill versus the conventionally applied bulk fill composite restorations in Class I cavities over 18-month follow-up periods.

Methods: 60 posterior teeth were used in this study in 20 patients (age ranging from 25-40). They were randomly divided into three equal groups (n=20) based on the type of restorative material employed. Each resin composite restorative system with the recommended manufacturer's adhesive was applied and cured according to the manufacturer's instructions. All restorations were evaluated clinically at baseline (after 24 hours), 6, 12, and 18 months according to the modified United States Public Health Service (USPHS) by two examiners for retention, marginal adaptation, marginal discoloration, secondary caries, postoperative sensitivity, color match, and anatomical form.

Results: All tested groups exhibited no significant difference regarding all the clinical evaluation criteria at all evaluation periods, except for marginal adaptation and discoloration. Marginal changes (Bravo score) were detected only after 12 months in 15% of Filtek bulk fill restorations (Group 1) only while all VisCalor bulk fill restorations in Group 2 and SonicFill 2 restorations in Group 3 recorded 100% Alpha scoring, with no statistically significant difference among the groups (P= 0.050). After 18 months, Bravo scores increased to 30% in Group 1, while 5 and 10% Bravo scores were recorded in restorations of Groups 2 and 3, respectively with a statistically significant difference (P= 0.049) among them. Marginal discoloration was observed after 12 months in Group 1 only, however, no statistically significant difference was found among the groups (P= 0.126). At 18 months, all tested groups had a statistically significant difference between them (P= 0.027).

Clinical significance: Reducing the composite viscosity either by thermo-viscous technology or by sonic activation can improve the material adaptation to the cavity walls and margins, thus improving the clinical performance.

Purpose: To evaluate in a retrospective practice-based clinical study, the effects of additional laser therapy on side effects following the removal of all four impacted third molars. The secondary objective was, based on those results, to rationalize a protocol for low-level laser therapy (LLLT) in terms of irradiation settings.

Methods: 96 subjects requiring simultaneous surgical removal of the four third molars were treated from 2017 to 2019. For each subject, one side was randomly assigned to laser treatment, the other receiving the placebo. LLLT was performed by applying an infrared diode laser of 810 nm. In the LLLT irradiated side of the mouth, three groups were randomly assigned to a specific protocol of irradiation. Controllable settings include power, energy density and also scanning technique. The main outcome was pain, registered on a visual analog scale (VAS) performed by the patients.

Results: There was a statistically significant difference for one of the tested protocols. Self-reported annoyance and pain scores were lower for the side submitted to a 30-second laser radiation at a power of 0.3 W with the slow scanning technique (P< 0.05).

Clinical significance: The present treatment approach, using a one-time low-level laser therapy intra-oral application, showed a beneficial effect of LLLT reducing pain after third molar surgery, which should be confirmed through further study.

Purpose: This systematic scoping review aimed to survey the literature to answer the following questions: which instruments were used to measure the color change; which teeth were assessed for color; what was the follow-up period, and in which country was the recently published tooth bleaching clinical trial performed?

Methods: This research was registered in the Open Science Framework. The following databases were searched: PubMed, Scopus, Web of Science, EMBASE, Cochrane Library, and LILACS. Randomized clinical trials evaluating tooth bleaching with color change analysis, published between 2021 and 2017, were included. The data extracted from included studies were analyzed using a qualitative and descriptive analysis.

Results: 106 articles were analyzed. Most studies used only ΔEab to measure the color change (10.4%), assessed the color change in the maxillary central incisors (45.3%), and included a one-month follow-up (25.4%). The published papers were mostly from research performed in Brazil (51.9%). Many methods have been used in the tooth bleaching clinical trials examined, and a wide variety of instruments used to measure the color change was observed.

Clinical significance: The large variation in the methodology criteria of most recent tooth bleaching clinical trials makes data comparison difficult among different studies and raises the need for a guideline for tooth bleaching clinical studies.

Purpose: To evaluate the effect of cycling whitening toothpaste with cigarette smoking (WTCS) on the evolution of roughness, color, translucency, and gloss of microfilled, microhybrid, and nanofilled resin composites.

Methods: 15 specimens of Durafill - DVS, Empress Direct - ED, and Z350 - FZ were divided into three groups according to the toothpastes:: conventional, control group, (Colgate - C) and Whitening (Colgate Luminous White - CW and Oral B 3D White - OW) and roughness, color, translucency, and gloss were evaluated before and after the specimens were submitted to WTCS for 8 weeks. Data were analyzed by two-way ANOVA, 3-way repeated measures ANOVA, and Tukey HSD post hoc test (α= 0.05).

Results: Only ED and FZ brushed with CW and FZ brushed with C presented an increase in roughness after WTCS. The three composites suffered a significant color alteration after WTCS. Excepting DVS brushed with CW, all the other groups presented a significant reduction in translucency after WTCS. DVS was the only resin composite that maintained its gloss stability after WTCS. Whitening toothpastes behaved similarly to conventional (control) toothpaste regarding the evolution of roughness and optical stability of the three resin composites.

Clinical significance: Whitening toothpastes were not capable of maintaining the color stability of the three resin composites after 8 weeks of toothpastes-cigarette smoking cycling.

Purpose: To evaluate the effect of whitening mouthrinses on the color change, whiteness change, surface roughness, and hardness of stained resin composites after different immersion times.

Methods: Three different resin composites (Estelite Σ Quick, G-Aenial Anterior, Omnichroma) were used to prepare a total of 90 samples (30 samples from each resin composite). The samples were kept in coffee for 12 days, then divided into three subgroups (Control, Crest 3D White, and Listerine Advanced White; n=10 each). Color change (ΔE₀₀) and whiteness change (ΔWID) were evaluated at time intervals of 0-24 hours (T0-T1), 0-72 hours (T0-T2), and 24-72 hours (T1-T2). Surface roughness and hardness values were evaluated at T0, T1, and T2 after immersion in mouthrinses. Two-way ANOVA (for color and whiteness changes) and generalized linear model (for surface roughness and hardness) were used for data analyses (P< 0.05).

Results: Omnichroma had the highest value for color change with Crest 3D White during T0-T1 and T0-T2. Crest 3D White showed better color changes than Listerine Advanced White. In all composites and mouthrinse groups, the highest and lowest values of ΔWID were at T0-T2 and T1-T2, respectively, with the highest value for Omnichroma with Crest 3D White at T0-T2 and the lowest for G-Aenial Anterior with control groups at T1-T2. The highest roughness values were found with the Omnichroma at T2. Whitening mouthrinses significantly increased roughness and decreased hardness compared to baseline.

Clinical significance: Short-term regular use of whitening mouthrinse can recover color and increase the perception of whiteness without any significant increase in the roughness or hardness of resin composites, while long-term use affects both the roughness and hardness of resin composites.