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Cleaning and shaping the root canal system are essential steps for performing successful endodontic therapy, and are challenging procedures in the apical region. This study aimed to conduct an ex vivo assessment of the debridement ability of the WaveOne Gold (Medium 35/.06) and TruNatomy (Medium 36/.03) systems in the apical third of round root canals of mandibular premolars. Forty-eight teeth, extracted for orthodontic or periodontal reasons, were divided into three groups (n=16), as follows: Group C, control (without instrumentation or irrigation); Group WOG, instrumentation with WaveOne Gold; Group TN, instrumentation with TruNatomy. A total of 40 mL of 2.5% sodium hypochlorite and 5 mL of 17% ethylenediamine tetraacetic acid were used per root canal in all the groups. Ten 0.5-µm serial cross-sections per specimen were obtained every 0.2 mm from a 2-mm segment of the apical region, extending from 1 to 3 mm short of the root apex. The sections were stained with hematoxylin-eosin and analyzed under a digital microscope (100x). The percentages of unprepared walls and remaining debris were quantified using ImageJ software. Generalized linear models were used to analyze the results (α=5%). Groups WOG and TN had significantly lower percentages of unprepared walls and remaining debris than Group C (p<0.05). There was no significant difference between groups WOG and TN for either of the variables studied (p>0.05). Instrumentation with the WaveOne Gold Medium and TruNatomy Medium instruments was associated with equivalent percentages of unprepared walls and remaining debris in the apical third of round canals of mandibular premolars.

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OBJECTIVE: To evaluate the effect of polyethylene fiber-reinforcement on the fracture resistance and fracture mode of extensive resin-based composite (RBC) restorations in structurally compromised maxillary premolars. METHODS AND MATERIALS: Maxillary premolars (54) with specific dimensions and extracted for orthodontic reasons were used. Following mesio-occluso-distal (MOD) cavity preparation and endodontic access, teeth were randomly assigned to one of three restorative protocols (n=18): RBC applied incrementally (I) or reinforced with woven polyethylene fibers (Ribbond) placed horizontally (H) or U-shaped (U). Restored teeth were stored for 45 days in distilled water at 37°C and then loaded monotonically until fracture. Half of the specimens in each group received axial loading (A) and the other half was loaded paraxially (PA). Fracture load data was assessed using two-way analysis of variance and Tukey's post hoc test for multiple comparisons (α=0.05). The fracture initiation and propagation path were analyzed using stereomicroscopy and scanning-electron microscopy. RESULTS: No significant differences were observed for the fracture strength among loading configurations, except for groups IA (825 N) and HA (553 N). Fracture initiated and propagated mainly at and through the RBC restoration in the I group, whereas a shift to the interface was observed in both polyethylene fiber-reinforced groups. Blocking and bridging of cracks were identified around the fibers, especially in specimens of group U. CONCLUSIONS: Incorporation of woven polyethylene fibers to reinforce extensive MOD resin-based composite restorations on endodontically treated premolars reduced the occurrence of cohesive fractures in the restorative material but was unable to increase the fracture resistance of the affected teeth.

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OBJECTIVE: Evaluate the penetration of hydrogen peroxide (HP) into the pulp chamber, bleaching efficacy (BE) and amount of gel expended during in-office bleaching using an applicator brush tip and conventional tip from different commercial brands. MATERIALS AND METHODS: 104 human premolars were randomly distributed into thirteen groups (n = 8) according to the commercial brand: DSP White Clinic 35 % Calcium (DW), Nano White 35 % (NW), Total Blanc One-Step 35 % (TS), Whiteness HP Blue 35 % (WB), Potenza Bianco Pro SS 38 % (PB), Opalescence XTra Boost 40 % (OB), no bleaching (negative control), and application method: applicator brush tip and conventional tip for all groups. Initial HP concentration (%) was determined via titration and pH was measured with digital pH meter. Concentration (µg/mL) of HP into the pulp chamber was measured using UV-Vis spectrophotometry, the BE (ΔE*ab, ΔE00 and ΔWID) was evaluated with a digital spectrophotometer, and the amount of gel expended was evaluated using a precision analytical digital balance. Statistical analysis included two-way ANOVA, Tukey's, and Dunnett's test. Comparison between HP into the pulp chamber vs BE was performed with Person's correlation (α = 0.05). RESULTS: Brush tip demonstrated a low amount of HP in the pulp chamber compared to the conventional method for all bleaching gels (p < 0.0003), as well as lower amount of gel expended (p < 0.002). The brush tip did not result in a significant difference in BE compared to the conventional (p > 0.05). No correlations were found between both factors (p > 0.05). CONCLUSION: Brush tip showed lower penetration of HP in the pulp chamber and a reduced volume of spent gel when compared to the conventional tip, for all commercial brands. CLINICAL RELEVANCE: Brush tip is recommended for bleaching gels in an attachable syringe due to its ability to reduce the penetration of HP into the pulp chamber and minimize the amount of bleaching gel used.

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OBJECTIVES: To evaluate the effect of whitening toothpastes with different hydrogen peroxide (HP) concentrations on HP permeability, color change, and physicochemical properties, compared to at-home bleaching treatment. MATERIALS AND METHODS: Forty-nine premolars were randomized into seven groups (n = 7): untreated (control); at-home bleaching with 10% carbamide peroxide gel (AH; 10% CP) with 14 and 28 applications of 180 min each (AH [14 × 180 min] and AH [28 × 180 min]); three whitening toothpastes (3% HP; 4% HP and 5% HP) and 10% CP brushed 28 times for 90 s each (TB [28 × 90 s]). HP permeability was measured using a UV-VIS spectrophotometer and color change by a digital spectrophotometer (ΔEab, ΔE00, and ΔWID). Initial concentration, pH, and viscosity were measured through titration, digital pH meter, and rheometer, respectively. Statistical analysis included one-way ANOVA, Tukey's test, and Dunnett's test (α = 0.05). RESULTS: 4% HP group showed acidic pH, the lowest viscosity and the highest HP concentration into the pulp chamber (p < 0.05). The 10% CP groups had lower HP in the pulp chamber and greater color change than other groups (p < 0.05), except the 5% HP group in ΔEab and ΔE00. For ΔWID, the 10% CP AH groups showed greater whitening than other groups (p < 0.05). CONCLUSIONS: Whitening toothpaste with up to 5% HP resulted in higher HP permeability and less color change compared to 10% CP. Higher HP commercial concentrations in toothpaste increased whitening effect; however, acidic pH toothpastes exhibited greater HP permeability. CLINICAL RELEVANCE: Whitening toothpastes with high hydrogen peroxide concentrations were less effective than at-home bleaching, resulting in less color change and greater permeability of hydrogen peroxide, potentially increasing the risk of tooth sensitivity.

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OBJECTIVE: This study aimed to clinically compare the accuracy of bracket positioning between three-dimensionally (3D) printed indirect bonding trays and vacuum-formed trays made over 3D-printed models. MATERIAL AND METHODS: Fourteen patients, planned for fixed orthodontic therapy, were randomly divided into two equal groups. For both groups, both dental arches were scanned, to acquire virtual models, brackets were virtually positioned from central incisors to second premolars, and scans for the final bracket positions were performed. In the first group, transfer trays were 3D-printed. In the second group, virtual models were 3D-printed, and vacuum-formed soft sheets were thermoformed on the printed model. Teeth were indirectly bonded and then scanned. Superimposition of the virtual and the final bracket positioning scans was performed to measure linear and angular deviations in brackets positions. RESULTS: The first group showed significantly less occlusogingival and buccolingual linear errors than the second group. No significant differences in angular deviations were found between both groups. The frequencies of clinically acceptable linear errors within 0.5 mm and angular errors within 2° showed no statistically significant difference between both groups (p> 0.05 for all measurements). The transfer errors in both groups showed linear directional biases toward the mesial, gingival and labial directions. There was no statistically significant difference in the rate of immediate debonding between both groups (10.7% and 7.1% for the first and the second groups, respectively, p=0.295). CONCLUSIONS: 3D-printed indirect bonding trays were more accurate than vacuum-formed trays, in terms of linear deviations. Both types of trays showed similar angular control.

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INTRODUCTION: Extraction vs. non-extraction is a crucial decision in orthodontic therapy. OBJECTIVE: The aim of the present study was to investigate the changes in the dental arch width and buccal corridor after orthodontic treatment using extraction and non-extraction therapy with Damon self-ligating system. MATERIAL AND METHODS: This retrospective study consisted of 35 patients (20 female and 15 male patients with median age of 12.5 years), treated by extracting 4 or 2 premolars, and 37 patients (16 female and 21 male patients with the median age of 12.8 years), treated without premolar extraction. Both groups were treated with Damon self-ligating system. Plaster models before (T0) and after (T1) treatment were measured, and the arch width values were determined at the level of the first molars, second premolars, canines and palatal rugae. Buccal corridor width was measured using the extraoral images at T0 and T1. Paired t-test was used for the analysis of the normally distributed data, and Wilcoxon Mann-Whitney U test was used for the data with non-normal distribution. Values of p<0.05 were set as statistically significant. RESULTS: The upper intercanine width increased significantly in both groups (p<0.01). In the non-extraction group, the arch width increased significantly in the maxillary second premolar and first molar region (p<0.01) as well as in the region of the canines (p=0.04), second premolars (p=0.01) and first molars (p<0.01) of the mandible. The buccal corridor decreased significantly in the non-extraction group (p<0.01). CONCLUSION: Premolar extraction in combination with Damon self-ligating system did not lead to reduction of the dental arch width in the maxilla, nor did it increase the size of the buccal corridors.

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OBJECTIVE: This descriptive observational study aimed to determine clinically relevant and applicable data of enamel thickness (ETH), considering the mesio-distal differences of anterior and posterior permanent teeth and their relationships. MATERIAL AND METHODS: The sample consisted of right-sided standardized radiographs of 34 individuals (21 females and 13 males), aged between 13 and 24 (average 16) years, with all permanent teeth intact and without crowding. Four periapical and four interproximal radiographs were obtained and digitized. ETH measurements (mesial to distal contact points at the dentin-enamel junction) were performed after correction for radiographic image magnification. The Students' t-test was applied to the differences between paired means, with the Pearson correlation to evaluate the correlation between them. RESULTS: The mesial and distal ETH increased from the anterior to the posterior teeth. Incisor ETH ranged between 0.60 and 0.84 mm. Canines, premolars, and molars were more than 1.0 mm thick, and molar enamel reached values between 1.26 and 1.44 mm. CONCLUSION: Distal ETH was significantly greater than the mesial ETH, and progressively thicker from the anterior to posterior teeth. Interproximal reduction (IPR) of the lower central and upper lateral incisors should be avoided, reduced, or performed on their distal surfaces. There is a positive and significant correlation between ETH and the mesial and distal surfaces of the teeth. Periapical radiographs and evaluation of the remaining ETH are necessary in cases of retreatment. The location and number of tooth size discrepancies should be considered in treatment planning and appropriately compensated with IPR.

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OBJECTIVES: To synthesise the dentoalveolar, periodontal and skeletal changes that occur when using maxillary expansion techniques assisted by temporary anchorage devices compared to conventional protocols. METHODS: Five databases and grey literature were consulted, up to December 2023, focusing on intervention designs and excluding other type of studies. The quality assessment was conducted by using the adaptation for orthodontics of the CONSORT statement, the guidelines for reporting non-randomised studies, the RoB-2 tool, and the ROBINS-I tool. A descriptive summary and meta-analysis using RevMan 5.4 were performed. RESULTS: Nine clinical trials were included (n=377 patients, mean age 13.2±0.6) with a diagnosis of transverse maxillary deficiency. The analysed studies showed qualitative dentoalveolar and periodontal changes after expansion, which were greater on the maxillary first premolars in tooth-borne appliances. Meta-analyses for some effects were included from two studies (n=64); patients who used tooth-borne appliances had greater effects of buccal intercoronal width between the premolars with statistically significant differences (Std Mean difference 2.34; 95% CI: 0.04-4.65 p=0.05). Conversely, those patients who used bone-borne or hybrid appliances had greater effects of buccal intercoronal width between molars with statistically significant differences (Std Mean difference -0.64; 95% CI: -1.38-0.10; p=0.09). CONCLUSIONS: According to the studies analysed, all measurements increased in the intervention groups after expansion. Quantitative analyses show different findings at dentoalveolar level when tooth-borne, bone-borne or hybrid appliances are considered. Nevertheless, the results should be taken with caution due to the heterogeneity of the studies. The protocol was registered at PROSPERO (CRD42021283170), with no funding to report.

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OBJECTIVE: To assess the effectiveness of a customized distalizer with Variety SP® screws anchored on palatal miniscrews for upper molar distalization. METHODS: Seventeen patients aged between 12.5 and 24 years underwent distalization with a customized distalizer. Lateral cephalogram and cast analysis were performed before and after distalization. Linear and angular parameters of the upper first molar, first premolar, and central incisor were assessed. RESULTS: Distalization with the force passing near the center of resistance (CRes) of the upper first molars resulted in distal movement, with minimal distal tipping (2.8 ±â€Š0.45°, p< 0.05). However, distalization passing occlusal to the CRes led to greater distal tipping (13.6 ±â€Š1.63°, p< 0.05). Statistically significant spontaneous distal tipping and distal movement of the upper first premolars occurred, with a mean of 6.2 ±â€Š1.24° (p< 0.05) and 0.68 ±â€Š0.34 mm (p< 0.05), respectively. The positional change of the upper central incisors presented a mean of -0.23 ±â€Š0.1 mm (p> 0.05) and 2.65 ±â€Š1.1° (p< 0.05). Upper first molar intrusion was statistically significant, with a mean of 0.88 ±â€Š0.2 mm (p< 0.05). Upper right and left first molars rotation towards palatal midline presented mean of 4.1 ±â€Š0.19° (p< 0.05) and 3.4  ±â€Š0.1° (p< 0.05), respectively. Additionally, the distance between upper right and left first molars increased significantly, with a mean of 2.54 ±â€Š0.01 mm (p< 0.05). CONCLUSION: The study successfully demonstrated the efficiency of molar distalization without anchorage loss using a customized distalizer anchored on palatal miniscrews.

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Identifying the presence, size, type and location of voids in an endodontic obturation is of great clinical importance because it enables evaluation of the three-dimensionality of the sealing techniques, which can be related to the success of the endodontic treatment. AIM: To analyze by micro-CT the presence of voids in lower single-rooted premolar root canal obturations prepared using the single cone and ultrasound vibration technique. MATERIALS AND METHODS: Twenty extracted single-rooted lower premolars were selected, and the root canal prepared surgically and chemically. In GROUP 1 - Without Vibration, the canal was obturated with a single cone and bioceramic, without applying vibration. In GROUP 2 - With Vibration, the gutta-percha cone inside the root canal was held with a cotton plier to which ultrasound vibration was applied for 3 periods of 3 seconds each. A micro-CT scanner was used to acquire and reconstruct images for analysis. RESULTS: No significant difference was found between obturation techniques, though there were differences between thirds, with the cervical third having a higher percentage of voids than the middle and apical thirds. CONCLUSIONS: The results suggest that the volume of closed, open and total voids does not differ between treatments with and without ultrasound vibration. In the cervical third, the highest volume of voids was related to oval geometry in the teeth evaluated.

La presencia de vacíos en la obturación endodóntica, su tamaño y el tipo y localización tiene gran importancia clínica ya que permite evaluar la tridimensionalidad de las técnicas de sellado y relacionarlas con el éxito del tratamiento endodóntico. OBJETIVO: analizar mediante microtomografía la presencia de vacíos en la obturación del conducto radicular de premolares inferiores unirradiculares, utilizando la técnica de cono único y vibración con ultrasonido. MATERIALES Y MÉTODOS: se seleccionaron 20 premolares inferiores unirradiculares a los que se les realizó la preparación quirúrgica y química del conducto radicular. Se realizó la obturación con cono único y biocerámico GRUPO 1- sin vibración. En el GRUPO 2 - con vibración se aplicó vibración por ultrasonido, se tomó del cono de gutapercha colocado en el interior del conducto con pinza de algodón que fue vibrada durante 3 períodos de 3 segundos cada uno. Las mismas fueron adquiridas y reconstruidas en un microtomógrafo para posterior análisis de las imágenes obtenidas. RESULTADOS: No se evidenciaron diferencias significativas entre ambas técnicas de obturación comparadas, pero si entre los tercios analizados, siendo el cervical el que mayor porcentaje de vacíos presenta en comparación a los cortes correspondientes al tercio medio y apical. CONCLUSIONES: Los resultados sugieren que el volumen de vacíos cerrados, abiertos y total no varía en los tratamientos donde se aplica vibración por ultrasonido. En el tercio cervical, el mayor volumen de vacíos se relaciona con la geometría oval que presentaron las piezas dentarias evaluadas en este estudio.

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