Little is written on obstacles for left-handed students in the dental clinic. This mixed methods study evaluates the experiences of using cordless keyboards for left-handed dental students. Researchers purchased four Logitech K400 Plus wireless keyboards. Using Qualtrics, a survey software, a pre-survey was sent out at the beginning of the spring semester prior to introducing the cordless keyboards. A post-survey circulated at the end of the semester. Quantitative analysis statistical analysis was conducted using IBM SPSS Statistics. Researchers conducted a thematic analysis of the qualitative survey responses. Twenty-three left-handed D3 and D4 dental students were asked to participate in a survey about cordless keyboards. The pre-survey had a 100% response rate, and the post-survey had a 71% response rate. The surveys indicated that left-handed students often face a range of barriers in clinical settings, including ergonomic challenges to enter data, difficulty managing time due to double entry of data on right-handed equipment, and feelings of psychological unsafety due to fear for asking for support. The most significant finding was as follows: not only did the cordless keyboard assist clinical performance, but the cordless keyboard project also helped students feel heard and validated as left-handed learners. Researchers recommend that educators prioritize the inclusion of left-handed learners through various practices like making adjustments to physical spaces and creating inclusive environments where all learners feel supported.
With the recent advent of technology, it is important to confirm the health and safety of the youth. This study aimed to prospectively evaluate the relationship between Wi-Fi, cordless phones, and mobile phone usage patterns and behavioral problems. This study involved 2465 children aged 8-17 years from the Hokkaido Study on Environment and Children's Health from October 2020 to January 2021, with a follow-up from September 2021 to March 2022. The mother-child dyad provided information on the presence of residential Wi-Fi and cordless phones, cordless phone call duration, and mobile phone usage pattern (duration of calls using mobile network and internet, online audio streaming, online video streaming, and playing online games) via a baseline questionnaire. Based on the scores on Strength and Difficulties Questionnaire at baseline and follow-up, the children were categorized into four groups: normal, persistent, improved, and concurrent. No significant association was found between Wi-Fi, mobile phone calls via mobile networks, and behavioral problems. Cordless phone at home had higher odds for improvement in total difficulty scores, and cordless phone for calling more than 4 min per week had lower odds of persistent problematic prosocial behavior. Longer duration of mobile phone calling via the internet (>40 min/week) had higher odds of concurrent total difficulties. Mobile phone calling via mobile network for <5 min per week had higher odds for improved total difficulty scores. Audio streaming via mobile phones for 60-120 min had lower odds of persistent total difficulties. Our results showed sporadic findings between residential RF-EMF indoor sources and mobile phone usage pattern. These observed findings could be affected by residual confounding and chance findings. Ongoing follow-up studies are necessary to further explore this association through detailed exposure assessment and addressing the potential limitations of our study.
This study aimed to evaluate and compare the inflammatory responses of two cordless gingival retraction systems by assessing the levels of interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in gingival crevicular fluid (GCF). The objectives were to measure IL-1β and TNF-α levels before and after retraction using kaolin-based and polyvinyl acetate-based cordless gingival retraction materials at baseline, 1 h, and 24 h, and to compare the inflammatory profiles of these materials. This in-vivo comparative study used a split-mouth design, with each of the 10 enrolled patients serving as their own control by receiving both kaolin-based paste (Traxodent®, Premier Dental Products, Plymouth Meeting, PA, USA) and polyvinyl acetate-based strip (Merocel®, Medtronic, Minneapolis, MN, USA) on different endodontically treated teeth requiring full-coverage crowns, thereby minimizing interindividual variability. The allocation of both agents to specific teeth was systematically determined based on clinical suitability and tooth position, alternating between the contralateral teeth to ensure consistent intraoral conditions. After oral prophylaxis and a 7-day washout period, baseline GCF samples were collected using sterile absorbent paper point (Dentsply Sirona, Charlotte, NC, USA). Traxodent®, a kaolin-based material, was applied to one tooth, and Merocel®, a polyvinyl acetate-based material, was applied to another tooth in each patient. GCF samples were collected at baseline, 1 and 24 h post-retraction, stored at -700C, and analyzed for IL-1β and TNF-α using enzyme-linked immunosorbent assay (ELISA) kits (Elabscience, New Delhi, India). Data were analyzed using independent t-tests for intergroup comparisons and repeated measures analysis of variance (ANOVA) with Bonferroni post-hoc tests for intragroup comparisons (p < 0.05). Both materials significantly increased IL-1β and TNF-α levels after 1 h. The polyvinyl acetate-based strip showed sustained IL-1β elevation at 24 h, whereas the IL-1β levels of the kaolin-based paste declined. Conversely, kaolin-based paste maintained elevated TNF-α levels at 24 h, whereas the polyvinyl acetate-based strip's TNF-α level decreased significantly. Both cordless retraction systems induced acute inflammation, with polyvinyl acetate-based strips causing prolonged IL-1β elevation and kaolin-based paste sustaining TNF-α levels. These findings suggest material-specific inflammatory responses, which can guide clinicians in selecting retraction systems to balance efficacy and periodontal health.
The aim of this paper was to reduce the current spikes in battery-powered saw motors by designing and implementing a sliding mode model-following adaptive controller. The proposed controller reduces overcurrent consumption, improves system energy efficiency, and effectively maximizes battery runtime, especially under high-load conditions. By applying nonlinear compensation techniques, the controller can ensure smooth motor operation, reduce mechanical stress, and prolong tool life. The results showed that this control strategy is particularly suitable for hand tools, where a long battery life is essential for efficient operation.
This study aimed to evaluate the impact of battery levels on the emission of a multi-peak cordless LED light-curing unit (LCU) and the effect on the degree of conversion (DC) and Knoop hardness (KH) of a light-cure resin luting agent activated through varying lithium disilicate (LiS2) ceramic thicknesses and translucencies. High and low translucency LiS2 discs (IPS e.max Press HT and LT, respectively; shade A1) with thickness of 0.5, 1.0, 1.5, and 2.0 mm were fabricated. Resin luting agent specimens (Variolink Esthetic LC) were prepared and cured using a Bluephase G2 LCU at different battery levels (100%, 50%, and 10%) through the LiS2 ceramics. The transmitted irradiance was evaluated using USB4000 MARC, while FTIR and a microhardness tester assessed DC and KH, respectively. After ensuring homoscedasticity, the data wee analyzed using analysis of variance and Tukey HSD test (α=0.05). The study found strong positive correlations between battery levels and irradiance, particularly with no ceramic interposition and through HT ceramics (R2=0.9471), although this correlation diminished with thicker HT (R2=0.7907) and LT ceramics (R2<0.2980). Both battery levels and ceramic thickness significantly influenced transmitted irradiance (p<0.0001), resulting in lower values with decreased battery levels and increased ceramic thicknesses (p<0.0001). LT ceramics showed lower transmittance than HT. DC was significantly affected by both battery levels and ceramic thicknesses, with generally lower DC values except for LT ceramics at a 10% battery level (p<0.0001). No significant differences in DC were observed between HT and LT translucencies (p=0.548). KH was higher in HT than LT ceramics at 100% and 50% battery levels, with thicker ceramics showing lower KH values at 10% battery level (p<0.0001). Conclusion: Reduced battery levels in cordless LED curing units significantly affect the irradiance, degree of conversion, and hardness of light-curable resin luting agents. Maintaining battery levels above 50% is recommended for optimal performance. Thicker and more opaque ceramics significantly impacted incident irradiance. However, preserving radiant energy could potentially mitigate these limitations.
The present clinical study aimed to assess the efficacy of conventional versus cordless displacement systems on gingival retraction for use with an intra-oral scanner and changes in periodontal indices. A total of 20 participants were selected for a split-mouth study (20 sites - Group Sc, 20 sites - Group Es). The outcomes were measured at day 0, day 1, and day 7 of follow-up in terms of Immediate horizontal displacement, Plaque Index, and Bleeding Index. Unpaired and Paired t-test was used as the parametric tests and statistical analysis was performed. A statistically significant change was observed in terms of BI on day 0, but no statistically significant change was observed for either group in terms of IHD and PI. The cordless material caused the least trauma to gingival tissue and was more compatible with intra-oral scanning devices.
This study aimed to assess the impact of battery levels in single-peak and multi-peak light-curing units (LCUs) on irradiance, and their effects on glass fiber post push-out bond strength to root dentin and the degree of conversion of dual-cure universal resin cement. Sixty bovine roots underwent endodontic treatment and were randomly distributed into 6 groups (n=10), formed by combining two LCUs (single-peak and multipeak) and three battery levels (100%, 50%, and 10%). A spectrophotometer measured irradiance (mW/ cm2) and spectral irradiance (mW/cm2/nm). Push-out bond strength (PBS) tests occurred at three root regions (cervical, middle, and apical), with optical and scanning electron microscopy for failure mode analysis. Degree of conversion (DC) was evaluated across the root regions. Data were analyzed using two-way repeated measures ANOVA and the Tukey HSD test. The Fisher exact test verified failure modes (α=0.05). As multipeak LCU battery levels decreased, emitted irradiance also diminished, with notable PBS reductions in the apical thirds. Failure modes were influenced by different conditions, primarily exhibiting mixed modes. Battery levels significantly impacted DC in the multipeak LCU, particularly in the cervical region, while the single-peak LCU exhibited DC reduction at the 10% battery level in the cervical region. Emitted irradiance, resin cement DC, and glass fiber post bond strength to root dentin may be influenced by varying cordless LCUs and battery levels.
Endoscopic nipple-sparing mastectomy (E-NSM) is a minimally invasive surgical technique that shows good results in patients with breast cancer. The authors compared 3 different types of commercial energy devices to examine their efficacy and safety in E-NSM performed with breast reconstruction. A total of 36 cases of E-NSM were conducted with either Sonicision (S group, n = 11), Harmonic (H group, n = 6), or Thunderbeat (T group, n = 19). The clinicopathologic factors and postoperative complications, including nipple or skin necrosis and surgical site seroma volume, were evaluated for 3 months after surgery. The surgical duration of E-NSM was significantly shorter in the S group than in the H group (P = 0.043) and T group (P = 0.037). However, the total surgical duration including E-NSM and breast reconstruction, and the total and daily drainage volume of postoperative seroma did not differ significantly among the 3 groups. Even when the energy devices were compared according to their working principle, i.e., ultrasonic (S and H) vs. hybrid (T), the total breast surgery duration and total and daily drainage volume of seroma showed no difference between the 2 groups. Although surgeon satisfaction did not significantly differ when using 3 devices for E-NSM (P = 0.428), surgeon's fatigue was found to be lowest in the S group, though it was not significant (P = 0.064). Any energy device can be safely used for E-NSM with breast reconstruction without causing any major complications. However, cordless ultrasonic energy devices allow greater mobility for the surgeon and, therefore, may shorten surgical time in breast surgery.
To measure the tip diameter (mm) and the ability to cover the anterior and posterior large restorations, radiant power (mW), radiant exitance (mW/cm2), emission spectrum (mW/cm2/nm), radiant exposure (J/cm2), the effect of the design on the access to the mouth posterior region, the temperature rise inside the pulp of three light-curing units (LCUs) and a new LCU available in the Brazil. Four LCUs that cost over US$900, three well-established (Bluephase G2, Ivoclar Vivadent; VALO Grand, Ultradent; and VALO Cordless, Ultradent), and a new LCU (Quazar, FGM) were tested in standard mode (20 s for all LCUs), high mode (3 s for VALO Cordless, 5 s for Quazar, and 20 s for Bluephase G2), and Xtra power mode (3 s for VALO Grand). The radiant power (mW) and emission spectrum (mW/nm) were measured using an integrating sphere connected to a fiberoptic spectroradiometer. The internal tip diameter (mm) of each LCU was measured using a digital caliper and was used to calculate the radiant exitance (mW/cm2). Radiant exitance profiles at the light tip were measured using a laser beam profiler. The radiant exposure (J/cm2) was calculated. The in vitro temperature rise produced by LCUs inside the pulp cavity of molar teeth was measured using a thermocouple. The mouth access of the LCU tip on the occlusal surface of the first mandibular molar tooth with two mouth openings of 25 mm and 45 mm at the incisors was evaluated. The cost of each LCU in Brazil was correlated with internal tip diameter, radiant power, and radiant exitance. All the LCUs were multiple-peak LCUs, and a uniform output. Quazar, VALO Cordless, and VALO Grand could maintain a perpendicular position regardless of mouth interincisal opening, while the Bluephase G2 required a tip angulation of 31.6 degrees at the 25 mm interincisal opening. The VALO Grand and VALO Cordless produced the highest temperature rise in standard mode ( 2.5°C), while in high mode, all LCUs produced lower temperature increases that use 5 s for Quazar and 3 s for VALO Grand and VALO Cordless, except for Bluephase G2, which produced a higher temperature rise ( 2.0°C) when activated for 20 s. There was a positive correlation between the cost of these LCUs and their averaged radiant power, diameter and the radiant exitance. The LCUs tested emit light in the blue and violet spectra, characterizing them as multiple peaks. The temperature increases in the produced pulp remained within safe thermal limits ( 2.5°C), although standard-mode exposures produced higher pulp temperature rises. Bluephase G2 created higher angulation at 25 mm of interincisal mouth opening. The Quazar LCU produced a light output that was comparable to that from leading LCUs.
This study compared heat generation and transfer through the dentin to the pulpal wall while curing two bulk-fill resin composites (BFRCs) with different light curing units (LCUs). A human molar tooth model was used to measure heat generation and transfer through the dentin to the pulpal wall while curing BFRCs with various LCUs. One hundred BFRC samples were divided into ten groups based on BFRC/LCU combinations (n = 10). Five LCUs with different spectral emissions (Bluephase G2, Bluephase PowerCure, D-Light Pro, Valo Cordless, Demi Ultra) were used for curing two BFRCs with different photoinitiator systems (Tetric EvoCeram Bulk Fill and Filtek One Bulk Fill). Measurements included temperature change (ΔT), time to maximum temperature (t), heat duration above threshold (Δt), and heat transfer rate (Q). One-way ANOVA (p < 0.001) and Tukey's post hoc test were used for analysis. Significant differences in ΔT, Δt, and Q values were found based on BFRC/LCU combinations (p < 0.001). Valo Cordless generated the lowest heat, while Bluephase G2 generated the highest heat. Bluephase G2 exhibited the longest duration above the threshold, while Valo Cordless had the shortest duration (p < 0.001). Valo Cordless and Demi Ultra produced lower heat transfer rates in the Filtek and Tetric groups, respectively. No significant differences were found in t values among BFRC/LCU combinations (p = 0.590). Heat generation and transfer from LCUs to dental pulp through dentin and BFRCs vary regardless of spectral emission. Different BFRCs with various photoinitiators produce differing heat levels, potentially increasing the risk of pulp injury. Selecting the appropriate combinations of LCUs and BFRCs can significantly reduce pulp damage risk.
Accurate recording of finish line margins is essential for the success of fixed prosthodontic restoration. Gingival displacement plays a crucial role in achieving adequate exposure of the subgingival margins, thereby ensuring proper marginal adaptation and long-term periodontal health. Various gingival retraction systems, including conventional cords and newer cordless materials such as pastes and gels, are available; however, their comparative effectiveness remains a topic of clinical interest. This study aimed to evaluate and compare the effectiveness of three commonly used gingival retraction systems in achieving gingival displacement based on pre- and post-retraction measurements. This prospective observational in vivo study included 15 systemically healthy participants aged 18-25 years old. Gingival displacement was evaluated on the maxillary right central incisor using three retraction systems: retraction cord (n = 15), astringent retraction paste (n = 15), and Racegel (n = 15). The control group (n = 15) had no gingival retraction. Baseline impressions were recorded without retraction, followed by post-retraction impressions after the application of each system under standardized conditions. Thus, each participant underwent four impression procedures, yielding a total of 60 impressions. One impression without gingival retraction served as the control, while three additional impressions were recorded following gingival displacement using the respective retraction systems. Consequently, 15 control impressions and 45 impressions after gingival retraction (15 per system) were obtained. The casts were sectioned and analyzed using a stereomicroscope and ImageJ software (National Institutes of Health (NIH), Bethesda, MD, USA). Horizontal and vertical displacements were measured in micrometers (µm). Statistical analyses were performed using one-way analysis of variance and post-hoc Tukey's tests. The mean horizontal displacement was highest in the retraction cord group (92.289 ± 28.724 µm), followed by Racegel (62.409 ± 21.978 µm) and retraction paste (58.213 ± 18.485 µm), with statistically significant differences among the groups (p < 0.001). Similarly, vertical displacement was greatest with retraction cord (458.530 ± 112.414 µm), followed by retraction paste (416.638 ± 110.911 µm) and Racegel (370.697 ± 68.476 µm), with significant differences (p < 0.001). The retraction cord demonstrated superior gingival displacement compared to the cordless systems. However, Racegel and retraction paste provided clinically acceptable results and may be considered alternatives in situations prioritizing patient comfort and minimal tissue trauma.
To evaluate the influence of the curing environment (benchtop vs. a simulated clinical technique) and light-curing unit (LCU) type (budget gun-style vs. a high-quality Valo Cordless pen-style) on the microhardness of a bulk-fill resin-based composite (RBC) placed in standardized Class II MOD cavities. Standardized MOD cavities were prepared in typodont teeth and restored with one bulk-fill RBC. Restorations were photocured on the benchtop or in a simulated clinical technique using either a budget gun-style LCU with a small tip or a high-quality pen-style LCU that has a wider tip. The Vickers microhardness was measured at the top, bottom, and longitudinal sections across mesial, central, and distal boxes of the RBCs. Bottom-to-top (B/T) microhardness ratios were calculated to evaluate curing adequacy. Data were analyzed using multivariate quantile regression (⍺=0.05). Benchtop curing with the Valo Cordless LCU produced significantly higher microhardness values than the simulated intraoral curing. Simulated conditions produced lower hardness values, particularly in the distal boxes, where the budget LCU often failed to achieve a clinically acceptable 80% B/T hardness ratio. The hardness values were greater in the central regions, while they were lower in the peripheral regions that received less energy due to access issues and tip angulation. Longitudinal analysis confirmed reduced curing depth at the bottom surfaces in all groups. Photocuring RBCs under standardized laboratory conditions produces better results than what can be achieved clinically. Polymerization efficiency is strongly affected by access to the RBC and by the LCU type. When used under simulated conditions in the posterior regions, budget LCUs with smaller tips produced inadequate curing. Thus, results reported from laboratory bench studies are unlikely to be achieved clinically. The results highlight the importance of testing products under patient simulator-based conditions to improve the clinical relevancy of in vitro studies.
All digital Wireless Communication (WC) electromagnetic field (EMF)/radiation (EMR) signals (from mobile/"smart" phones and corresponding base antennas, cordless domestic phones, Wireless Fidelity (Wi-Fi) routers, "Bluetooth" wireless connection among electronic devices, etc.) are emitted discontinuously, in the form of on/off pulses repeated at various Extremely Low Frequency (ELF) rates. Yet, many scientists ignore/underestimate these ELF pulsations, and characterize all WC emissions simply as Radio Frequency (RF)/Microwave (MW) signals. Here, we provide recordings of ELF pulsations with respect to time, emitted by the most common WC devices, specifically Wi-Fi router, 4th and 5th Generation (4G, 5G) mobile phones. We used a broadband antenna, connected to an RF spectrum analyzer (SA), calibrated the SA at the signal's carrier MW frequency and recorded the power of the final emitted RF/MW signal with respect to time. We recorded emissions at 10 ms, 100 ms, 1 s, and 2 s sweep times, capturing the pulses repeated at various ELF rates, clearly showing the ELF pulsing emissions from the WC devices. As in all real WC EMF signals emitted by commercially available devices and corresponding antennas, there is intense variability in the amplitude, shape, duration, and repetition frequency of the pulses. The present study, in combination with the Ion Forced Oscillation and Voltage-Gated Ion Channel (IFO-VGIC) mechanism of non-thermal EMF-bioeffects, imply that the non-thermal biological and health effects of WC EMFs are induced by the ELF pulsation, modulation and variability, and not by the standalone (non-modulated) RF carrier wave EMFs which can produce only heating. Electromagnetic fields/radiation (EMFs/EMR) emitted by digital wireless communication (WC) devices (mobile/“smart” phones, cordless domestic phones, Wireless Fidelity (Wi-Fi) routers for connection to the Internet, etc.) and corresponding base antennas, are usually referred to simply as Radio Frequency (RF: 300 kHz–300 GHz) EMFs/EMR. Yet, as we have repeatedly declared before, this reflects only one part of the reality. The other part is that the RF signals that carry the transmitted information (text, speech, music, images, video, etc.) are contained within on/off pulses which are emitted/repeated at various Extremely Low Frequency (ELF: 3–3000 Hz) rates. Moreover, the RF signal within the pulses is modulated mostly by ELF EMFs, and the final signal contains random variability especially in amplitude which lies mainly in the Ultra-Low Frequency (ULF: 0–3 Hz) band. Therefore, all WC EMFs are a combination of high (RF) and low (ELF/ULF) frequencies. To record the ELF pulses, specific methodology and instrumentation are required. Here, we have recorded these pulses (as power with respect to time) from the most common WC EMFs/EMR, namely Wi-Fi, 4th, and 5th Generation (4G, 5G) WC EMFs/EMR. The present study, in combination with a widely accepted biophysical mechanism, the Ion Forced Oscillation and Voltage-Gated Ion Channel (IFO-VGIC) mechanism, of non-thermal EMF-bioeffects, imply that the non-thermal biological and health effects associated with exposure to WC EMFs are induced by the ELF/ULF pulsation, modulation and variability, and not by the standalone (non-modulated) RF carrier wave EMFs which can produce only heating at adequately high intensities rarely found in the environment.
Stereoelectroencephalography (sEEG) procedures require drilling serial burr holes for electrode placement. Key drilling characteristics include haptic feedback, ease of use, and time-efficient burr hole creation. Orthopedic drill bits are often repurposed for sEEG. We present a case series highlighting sEEG as an application for a new-to-market neurosurgery-tailored drill. We performed a retrospective chart review on patients who underwent sEEG at our institution from 2022-2023. Patients were grouped by type of drill, Phasor® (a disposable battery-operated drill 3.20-mm diameter, 210-mm usable length) or Stryker® (Orthopedic Drill Cordless). Twelve patients underwent sEEG with the neurosurgery-tailored drill (2 unilateral and 10 bilateral); on average 10.7 ± 1.6 electrodes were placed per patient and mean operative duration was 162.9 ± 49 min. Tactile feel of bony layers and consistent drill time per burr hole (< 15 s) was subjectively noted. No complications were noted. Five patients underwent sEEG with the Stryker® orthopedic drill (2 unilateral and 3 bilateral); an average of 11 ± 2.9 electrodes were placed per patient, mean operative duration was 176.4 ± 18.9 min. Subjectively, drill time per burr hole was variable and increased in duration between the first and final hole. One patient incurred a skin burn at the drill site which led to wound dehiscence and infection requiring prolonged wound care and antibiotics. The Phasor® drill offers a lightweight, reliable, consistent, safe and efficient option for sEEG burr hole creation and may be considered as an alternative to the Stryker® orthopedic drill.
This study evaluated the effect of different light-curing units on the conversion degree of resin materials used for luting glass fiber posts and the bond strength to root dentin. One hundred bovine roots received endodontic treatment and were randomly assigned to five groups (n = 10) according to the luting material: RelyX U200 (self-adhesive resin cement), RelyX Ultimate (adhesive resin cement), Filtek Bulk Fill Flow (bulk-fill flowable composite with camphorquinone), Tetric N-Flow Bulk-Fill (bulk-fill flowable composite with ivocerin), and Filtek Supreme Flowable (flowable composite resin). Light activation was performed using either an LED singlewave (Radii Plus) or a polywave LED (Valo Cordless), both at 1000 mW/cm². The degree of conversion was analyzed using Raman spectroscopy, and bond strength was assessed using the push-out test, followed by failure mode analysis. ANOVA and Tukey (α=0.05) demonstrated that RelyX Ultimate and Filtek Bulk Fill Flow provided higher strength values, different (p<0.05) from Tetric N-Flow Bulk-Fill, RelyX U200, and Filtek Supreme Flowable, which had the lowest values. Regarding light-curing units, LED polywave showed the highest bond strength difference (p<0.05) from LED singlewave. Adhesive failures were predominant across all groups, regardless of the material, light source, or root third. RelyX U200, RelyX Ultimate, and Filtek Bulk Fill Flow showed a higher degree of conversion than Tetric N-Flow Bulk-Fill and Filtek Supreme Flowable. Overall, both the choice of luting material and the light-curing unit influenced bonding effectiveness. RelyX Ultimate and Filtek Bulk Fill Flow showed superior performance, and the polywave LED generally produced better adhesion outcomes.
Chemotherapy-induced alopecia is a common side effect with psychological impacts that affect quality of life. Up to 14% of patients may decline chemotherapy due to concerns over hair loss. While existing scalp cooling therapies can reduce alopecia, constraints including space, staffing, and extended chair time limit their use in health services. Hence, a novel scalp cooling cap ("Product X") was developed to address this gap. Product X is cordless and portable and does not require patients to remain in treatment chairs post-chemotherapy. This early-stage cost-effectiveness analysis addresses the potential economic value of adopting Product X versus current practice (no scalp cooling). We developed a decision tree and a lifetime Markov model to estimate change to total costs and health benefits for female patients with early breast cancer, from a health system perspective in a Singapore tertiary cancer care setting. The model incorporated costs related to scalp cooling equipment and administration, chemotherapy, and treatment for cancer recurrence. Assumptions regarding Product X's efficacy and its potential impact on chemotherapy compliance were tested in nine scenario analyses (efficacy: 50%, 75%, 100%; compliance improvement: 0, 1%, 5%). Probabilistic scenario analysis was conducted using Monte Carlo simulation with 1000 iterations from appropriate parameter distributions. In the base case (1% improvement in compliance and 100% efficacy), Product X yielded an incremental cost of S$265 per patient (95% UI: S$251-S$281) and incremental quality-adjusted life years (QALY) of 0.0717 (95% UI: 0.0705-0.0729). At a willingness-to-pay of S$45,000 per QALY, incremental net monetary benefits (INMB) was S$2961 (95% UI: S$2906-S$3015), with >99.9% probability of cost-effectiveness. Across all scenarios, INMB ranged from S$1158 to S$3330. Scenario and probabilistic analyses suggest that Product X is a cost-effective solution for chemotherapy-induced alopecia, supporting its adoption from a health system perspective.
To evaluate the efficacy of a new orthodontic primer (Ambar APS Ortho; FGM Dental Products, Joinville, SC, Brazil) on shear bond strength (SBS) and degree conversion (DC) of metallic brackets bonding. 240 sound maxillary premolars were randomized into 24 experimental groups based on: (1) Orthodontic primer (Ambar APS Ortho, Orthoprimer and Transbond XT); (2) Light-curing time (3-seconds and 10-seconds); (3) Light-curing unit (Valo Cordless and Quazar); and (4) Storage condition (immediate time [IT] and after thermocycling [TC]). After each storage time, specimens were subjected to SBS testing at a crosshead speed of 1 mm/min until failure, and values were recorded in MPa. For DC (%) analysis, adhesive discs were prepared and evaluated using micro-Raman spectroscopy at IT only. SBS and DC data were analyzed using four and four-way ANOVA, respectively and Tukey's post hoc test (α = 0.05). Ambar APS Ortho showed significantly higher SBS values across both light-curing units compared to all other groups (p = 0.0001). For DC, Orthoprimer showed the lowest values, while Ambar APS Ortho achieved the highest. Across all primers, a 10 s light-curing exposure resulted in significantly higher DC values compared to 3 s (p < 0.0001). Ambar APS Ortho exhibited superior performance in both SBS and DC, for both 3 s and 10 s light-curing times as well as IT or AT, supporting its reliability for bonding metallic orthodontic brackets.
Background/Objectives: The performance of the adhesive system used for bonding fundamentally influences the success of fixed orthodontic treatment. To withstand masticatory forces and prevent bracket debonding, it is critical to achieve optimal shear bond strength (SBS), improving treatment time. The aim of this study was to compare the shear bond strength and adhesive remnant index (ARI) of orthodontic brackets bonded using LED light-curing units with intensities of 3200 mW/cm2 at two different exposure times, evaluated after 24 h and 14 days. Methods: Eighty extracted permanent premolars were randomly divided into four experimental groups. Brackets were bonded using Transbond XT adhesive and cured with a VALO™ Ortho Cordless unit (3200 mW/cm2) for 3 or 6 s. SBS was measured using a universal testing machine, and the ARI was assessed under a stereomicroscope at 40× magnification. Results: Increased light intensity and longer curing time significantly improved SBS values. The highest bond strengths were observed in groups cured with 3200 mW/cm2 for 6 s, after 14 days. ARI scores showed that longer curing reduced adhesive remnants on the enamel. Statistical analysis confirmed significant differences among groups. Conclusions: Therefore, clinicians may achieve better bonding performance and easier enamel clean-up by using high-intensity lights with adequate curing duration.
The aim was to assess the amount of gingival displacement in digital impressions and gingival height loss up to one month after cementation of the final crowns. Thirty-two participants with maxillary premolars indicated for full crown restorations were randomly allocated into four groups according to the gingival displacement method: Retraction cord with astringent (RCA), Cordless paste with astringent (EXP) (Expasyl; Acteon LTD), Cordless paste without astringent (MF) (Magic FoamCord; Coltenewaldent AG) and Laser troughing (LT). Preoperative digital impressions were made, followed by full crown preparation and then application of the gingival displacement methods. The prepared teeth were scanned immediately after gingival displacement procedures. Horizontal and vertical gingival displacement and sulcus depth were measured in the intraoral scans. After the final cementation of the crowns, gingival height loss was assessed on the 7th,15th, and 30th day timepoints. Data were analyzed using One-way ANOVA and Two-way Repeated Measures ANOVA, followed by multiple pairwise comparisons using Bonferroni adjusted significance level. Group RCA exhibited a statistically significant superior horizontal and vertical displacement and sulcus depth compared to the other groups followed by Magic FoamCord (P < .05). The horizontal and vertical displacement values for Group RCA were 0.66 ± 0.04 mm and 0.66 ± 0.008 mm, respectively. In contrast, for the remaining groups, horizontal displacement ranged from 0.25 mm to 0.38 mm, while vertical displacement ranged from 0.24 mm to 0.48 mm. After one month, RCA recorded the highest statistically significant loss in gingival height compared to all other groups (P < .001). Vertical and horizontal displacement were most pronounced with impregnated cords, followed by Magic FoamCord, and were less significant with Expasyl and Diode laser. The use of an impregnated cord resulted in a greater loss of gingival height after one month. For capturing the finish line in digital impressions for subgingival preparations, the use of impregnated retraction cords or cordless retraction paste without astringent in conjunction with compression caps proved effective in achieving displacement of gingival tissues. However, traumatic pressure should be avoided with impregnated cords to minimize gingival height loss.
This study aimed to investigate the effects of three polymeric coatings-polyethylene glycol (PEG), polyether ether ketone (PEEK), and polydopamine (PDA)-applied onto the external surfaces of hybrid CAD/CAM dental composites, on their biological and mechanical performance. Disc-shaped specimens were fabricated from three CAD/CAM hybrid materials: Cerasmart (CS), Vita Enamic (EN), and Lava Ultimate (LU). Prior to coating, all discs were exposed to pressurized nitrogen gas to eliminate potential surface contaminants. Each specimen surface was then treated with GC G-Multi Primer according to the manufacturer's instructions and gently air-dried for 30 s without subsequent light-curing. A layer of Optiglaze Color Clear was subsequently applied and photo-polymerized for 40 s using a high-intensity LED curing unit (Valo Cordless, 1000 mW/cm², Ultradent, South Jordan, UT, USA). No acid etching was performed before primer application in order to preserve the structural integrity of the substrates. To standardize the surface condition, this Optiglaze pretreatment was identically applied to all specimens-including the uncoated control groups-ensuring that any observed differences in performance could be attributed exclusively to the polymer coatings. Each disc was then surface-coated with one of the selected polymers using a spin-coating technique. Surface characterization was conducted using Fourier-transform infrared (FTIR) spectroscopy (Nicolet iS10, Thermo Fisher Scientific, USA), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX) (Hitachi SU3500, Japan), and X-ray diffraction (XRD) analysis (Rigaku MiniFlex 600, Japan). Fibroblast adhesion and viability were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay at 24 and 48 h. Mechanical properties-including scratch resistance (via Revetest scratch test), nanohardness (Vickers), and elastic modulus-were quantitatively evaluated. Scratch testing was performed exclusively on polymer-coated CAD/CAM discs (PDA, PEG, PEEK), not on uncoated substrates, to assess the near-surface mechanical response of the coatings and their adhesion to the underlying substrates. Film thickness was quantified by profilometry on polymer coatings deposited under identical spin-coating conditions onto smooth silicon witness wafers, whereas surface roughness was directly measured on the coated CAD/CAM substrates using AFM. This approach ensured that thickness assessment was not confounded by the heterogeneous microstructure of the restorative substrates. Hydrophilic behavior was evaluated by static water contact angle measurements, and hydrolytic stability was determined through water sorption and solubility tests. All coatings significantly enhanced fibroblast adhesion (p < 0.05), with PDA demonstrating the strongest effect at 48 h. Cell viability was significantly influenced by both coating type and substrate composition (p < 0.001). Among mechanical properties, PEEK-coated EN specimens showed the highest scratch resistance, whereas PEG-coated LU specimens exhibited the lowest. All coatings reduced water contact angles relative to controls, indicating improved surface wettability. PEEK-coated specimens displayed the lowest water solubility and the highest nanohardness, while PEG coatings produced the highest elastic modulus. Surface roughness was primarily dictated by substrate composition, with no significant effect of coating type. Although CAD/CAM composites possess favorable intrinsic mechanical properties, their surfaces lack optimal bioactivity. The application of ultrathin polymer coatings-particularly PEEK and PDA-demonstrated considerable potential to enhance both soft-tissue compatibility and structural durability. These findings underscore the translational relevance of polymer-based coatings in restorative dentistry, with implications for extending restoration longevity, improving soft-tissue sealing, and reinforcing functional performance.