SEARCH · Search PubMed

Results for “Air Abrasion, Dental”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

76 records · Page 3Linked to original sources

PubMed2026

Challenges and future directions in AI-driven biomaterials for microbiome-associated oral infectious diseases: A systematic review.

Oral biofilm-induced antimicrobial resistance is the core pathogenic mechanism of microbiome-associated oral infectious diseases (dental caries, periodontitis, peri-implantitis, and endodontic infection). Traditional therapies and biomaterials are limited by poor biofilm penetration, drug resistance induction, single functionality, and inadequate adaptation to dynamic oral microenvironmental changes (e.g., pH fluctuations, salivary rinsing, masticatory stimulation). Artificial intelligence (AI) has transformed the field by integrating materials science, microbiology, and stomatology data. Via machine learning, deep learning, and multi-physics simulation, AI optimizes biomaterial physicochemical properties, decodes microenvironmental signals, constructs precise sensing-response loops, and supports the full chain of material design, performance prediction, and action simulation, advancing treatment from empirical intervention to precision regulation. This systematic review retrieved literature from PubMed, Embase, and Web of Science (January 2016-January 2026) using keywords across three dimensions: AI, biomaterials, and oral microbiome. Following inclusion/exclusion criteria, 99 articles were included. It elaborates on five core mechanisms of AI-driven oral biomaterials (precise oral microbiome analysis, targeted material design/optimization, performance prediction/simulation, targeted delivery/intervention, effect evaluation/dynamic regulation), analyzes their applications in microbiome-targeted biomaterial research and development (R&D) and clinical practice for the four major oral infectious diseases, addresses technical bottlenecks (insufficient targeting specificity and precision of biomaterials, poor stability and durability in complex oral microenvironments, inadequate biofilm disruption capacity, and clinical translation obstacles), and proposes future directions (multimodal design to enhance targeting specificity, structural and component optimization to improve stability/durability, development of multi-mechanism synergistic biofilm disruption strategies, strengthening translational research for clinical application, and deep integration of AI in the full chain of biomaterial R&D). This work provides comprehensive theoretical and practical support for the R&D, optimization, and clinical translation of AI-driven microbiome-targeted oral biomaterials.

Humans↗

PubMed2026

Effectiveness of different anaesthetic techniques, agents and adjunctive interventions in handling pain during dental treatment of MIH-affected teeth: a systematic review.

BACKGROUND: Molar incisor hypomineralisation (MIH) is frequently associated with hypersensitivity, dental anxiety and reduced efficacy of local anaesthesia, complicating pain control during dental treatment in children. AIM: To evaluate, based exclusively on randomised controlled trials (RCTs), the effectiveness of different local anaesthetic techniques, agents and adjunctive interventions in reducing pain during dental treatment of MIH-affected teeth in children. METHODS: A systematic review was conducted following PRISMA 2020 guidelines and registered in PROSPERO (CRD420251150485). MEDLINE, Cochrane Central, ScienceDirect, SCOPUS, EBSCO, and LILACS were searched up to September 2025. Eligible studies were RCTs involving children and adolescents (6 - 18 years-of-age) with MIH, assessing pain outcomes during dental procedures. Risk of bias was assessed using the Cochrane RoB 2 tool, and certainty of evidence was evaluated using the GRADE approach. RESULTS: Eight RCTs were included. Low-certainty evidence suggested that intraosseous anaesthesia and 4% articaine may reduce intra-operative pain compared with conventional techniques or 2% lidocaine. Adjunctive cryotherapy and pre-emptive ibuprofen showed potential benefits, but evidence was of very low certainty and limited to single trials. Findings for photobiomodulation were inconsistent across studies. Most trials were judged to be at high risk of bias, primarily due to lack of blinding and reliance on subjective pain outcomes. CONCLUSION: Current evidence supporting specific pain management strategies for MIH-affected teeth is limited and of low certainty. Whilst 4% articaine and intraosseous anaesthesia appear promising, well-designed, adequately powered RCTs with standardised pain outcomes are required to inform robust clinical recommendations.

Local anaesthesia↗

PubMed2026

Effectiveness of high-power laser use in the removal of esthetic restorations: a systematic review.

This systematic review aimed to evaluate the effectiveness of high-power lasers in the removal of esthetic restorations compared with conventional methods. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and registered in PROSPERO (registration number: CRD420251055736). A comprehensive electronic search was performed in MEDLINE, Scopus, Embase, Web of Science, and the Cochrane Library. Study selection, data extraction, and methodological quality assessment were independently performed by four reviewers using QUIN tool for in vitro studies. A total of 2.384 records were identified, of which 19 in vitro studies conducted on extracted human permanent teeth met the eligibility criteria and were included in the qualitative synthesis. The included studies evaluated different high-power laser systems, predominantly Er: YAG and Er, Cr: YSGG lasers, as well as CO₂ lasers. Five studies were classified as high quality, whereas the remaining fourteen studies were classified as moderate quality. Available laboratory evidence suggests that laser-assisted techniques may represent a potential alternative approach for removing esthetic restorations, with advantages including conservative tissue removal, reduced damage to underlying tooth structures, and intrapulpal temperature increases within acceptable limits. The Er: YAG laser was the most frequently investigated system, with power settings ranging from 1.5 to 5.9 W, showing particularly favorable laboratorial performance in the removal of lithium disilicate restorations, especially in thinner substrates. Within the limitations of the available evidence, high-power lasers appear to be a promising and minimally invasive alternative to conventional methods for the removal of esthetic restorations. However, the predominance of in vitro studies highlights the need for well-designed clinical trials to confirm these findings and support their clinical application.

Humans↗

PubMed2026

Impact of a CARE-ORIENT Education Program on Oral Hygiene Among Institutionalized Older Adults: A Double Blinded Cluster Randomized Controlled Study.

BACKGROUND: Older adults residing in long-term care facilities often depend on caregivers for daily oral care. Inadequate caregiver training may contribute to poor plaque control and denture hygiene. METHODS: A six-month parallel-arm cluster randomized controlled study was conducted in selected long-term care facilities in Northern India. Two old age homes were randomly selected, with one allocated to the intervention group and the other to the control group. A total of 150 older adults and 46 caregivers participated. Caregivers in the intervention group received a structured caregiver oriented oral health education. Clinical assessments were performed at baseline, 3 and 6 months. Outcomes included Debris Index, Turesky-Gilmore-Glickman Plaque Index, Denture Plaque Index and Denture Stomatitis Index. Caregiver knowledge and practice were evaluated using a validated questionnaire. RESULTS: Caregiver knowledge and practice scores improved significantly in the intervention group at 3 and 6 months. Significant differences were observed in Debris Index (DI), Plaque Index (PI), and Denture Plaque Index (DPI) in the intervention group over the six-month follow-up (p < 0.001). The Debris Index decreased from 2.76 ± 0.07 at baseline to 1.54 ± 0.05 at 6 months. Plaque Index scores declined from 3.26 ± 0.06 to 1.85 ± 0.08, and Denture Plaque Index scores reduced from 3.22 ± 0.03 to 1.74 ± 0.05. Denture Stomatitis Index improved over time; however, intergroup differences were not statistically significant. CONCLUSION: Structured caregiver-focused oral health education significantly improved oral hygiene among institutionalized older adults over six months, supporting integration of caregiver training within routine long-term care.

Humans↗

PubMed2026

Littoral and wetland vegetation decrease carbon emissions from dry inland waters.

Lakes are recognized as active components of the inland water carbon (C) cycle, as organic matter is processed by microbial respiration, inducing large carbon dioxide (CO2) and methane (CH4) emissions. In the context of long-lasting drought periods, large uncertainties remain about: (1) the influence of wet-dry cycle on CO2 and CH4 fluxes in littoral zones and lacustrine wetlands; and (2) the contribution of emergent vegetation to C fluxes in dry inland waters. At the water-land interface of two shallow lakes, this study focuses on CO2 and CH4 fluxes from vegetated and bare dry inland waters in relation to hydrological fluctuations. Three seasonal campaigns were conducted to measure daytime CO2 and CH4 fluxes in pelagic, littoral and wetland surface waters, as well as in temporarily air-exposed sediments, using floating and static chambers, respectively. Our results reveal that wet-dry cycle in the littoral zone and wetlands strongly influence gaseous C fluxes through contrasting patterns, especially in late summer, when the biological processes are most active (primary production and respiration). In air-exposed littoral zones, organic-poor sandy sediments presented the lowest CO2 and CH4 emissions, whereas in air-exposed lacustrine wetlands, water-saturated sediments accumulated high amounts of plant-derived organic matter, promoting intense microbial activity and the highest C emissions. However, amphiphytes and helophytes vegetation in exposed littoral zones and wetlands reversed the direction of C fluxes, inducing the highest CO2 uptake due to high photosynthesis rates. This study underlines the relevance of considering vegetation in dry inland waters, particularly in lacustrine littoral zones and wetlands, to obtain comprehensive lake C budgets, especially under climate change scenarios.

Wetlands↗

PubMed2026

Clinical Performance of Bulk-Fill Versus Incremental Composite Placement Approaches in Vital Posterior Teeth: A 24 Months Randomized Controlled Trial.

BACKGROUND: Composite resin placement technique may influence marginal integrity, polymerization stress distribution, and long-term clinical performance of posterior restorations. This randomized controlled clinical trial evaluated the 24-month clinical performance of four different placement techniques in Class I posterior composite restorations. METHODS: Fifty patients aged 20-35 years presenting with four occlusal carious lesions each were enrolled, resulting in 200 restorations. Cavities (4-5 mm depth) were prepared according to caries extension. Restorations were randomly allocated into four equal groups (n = 50) according to placement technique: stamp technique, snowplow technique, modified incremental "pizza" technique, and bulk-fill technique. All materials were applied following manufacturers' instructions. Clinical evaluation was performed at baseline and after 6, 12, and 24 months using FDI criteria. Functional (fracture/retention, marginal adaptation), esthetic (marginal staining, anatomical form), and biological (postoperative sensitivity, secondary caries) properties were assessed by two calibrated evaluators. Statistical analysis was performed at a significance level of α = 0.05. RESULTS: Thirty-eight patients with a total of 152 restorations were evaluated at the end of the 24 months in line with FDI at the end of the study with 76% recall rates. No statistically significant differences were observed among groups regarding fracture/retention or secondary caries (p > 0.05). Marginal adaptation and marginal staining demonstrated minor deterioration over time across all groups, with statistically significant intergroup differences found (p < 0.05). Postoperative sensitivity was minimal and transient in all groups with no significant difference (p = 0.181). CONCLUSIONS: Within the limitations of this 24-month follow-up, the four placement techniques demonstrated comparable clinical performance in Class I posterior composite restorations. Selection of technique may therefore be guided by clinical preference and procedural efficiency rather than differences in short-term clinical outcomes. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT07415317.

Humans↗

PubMed2026

Pre-clinical evaluation of the anticaries effect of an experimental Malva sylvestris extract mouthwash using a cariogenic model in situ.

OBJECTIVE: The aim of this study was to evaluate the antimicrobial and anticariogenic potential of Malva sylvestris extract on enamel and dentin in situ. METHODS: A double-blind crossover in situ study was conducted with 12 participants wearing palatal appliances containing two bovine enamel and two dentin specimens per 3 phases, a total of 72 enamel and dentin specimens. Biofilm formation and daily sucrose exposure were allowed. Treatments were applied twice daily in three phases: Malva sylvestris (2.5%, MS); fluoride (225 ppm, F); and placebo (P). After seven days, biofilm was collected from the bovine specimens for analysis of Lactobacillus spp. and mutans streptococci by Colony Forming Unit counts (CFU log₁₀/mL). Dental demineralization of the bovine specimens was assessed by transverse microradiography (TMR). RESULTS: MS did not reduce Lactobacillus spp. counts (CFU log₁₀/mL: enamel 6.63±0.81; dentin 6.68±0.92) compared to P (6.63±0.70; 6.62±0.51). F also did not differ (6.29±0.75; 6.32±0.41; ANOVA/Tukey, p>0.38). Mutans streptococci data were inconclusive. In enamel, both MS (2320.8±768.2 %vol·µm; 101.6±27.0 µm) and F (1777.3±733.3 %vol·µm; 95.8±23.5 µm) significantly reduced integrated mineral loss and lesion depth compared to P (3517.2±1119.9 %vol·µm; 138.6±19.5 µm; ANOVA/Tukey, p≤0.0003). In dentin, MS significantly reduced integrated mineral loss (322.5 [250-580] %vol·µm) and lesion depth (30.1 [15-42.2] µm) compared to P (880 [580-1705]; 58.3 [32.2-88.6] µm; Kruskal-Wallis/Dunn, p≤0.001), while F (587.5 [305-720]; 25.2 [16.5-38.8] µm) did not differ significantly (p>0.05). CONCLUSIONS: Malva sylvestris extract had no antimicrobial effect on Lactobacillus spp. counts, but significantly reduced enamel and dentin demineralization, showing anticaries effect comparable to fluoride. CLINICAL RELEVANCE: Malva sylvestris has demonstrated promising biological activity. This study investigates the antimicrobial efficacy of Malva sylvestris against cariogenic microorganisms in situ. Our findings provide relevant evidence that M. sylvestris exert significant anticaries effects using an in situ model.

Biofilms↗

PubMed2026

Soft Tissue Volume Augmentation at Single Implant Sites Applying Collagen Matrices or Connective Tissue Grafts: 10-Year Follow-Up of a Randomized Controlled Trial.

AIM: To compare up to 10 years clinical, profilometric and patient-reported outcomes of implant sites previously augmented using a volume-stable collagen matrix (VCMX) or connective tissue graft (SCTG) in the aesthetic zone. METHODS: The original non-inferiority randomized controlled trial (RCT) enrolled 20 patients who received soft tissue volume augmentation with VCMX or SCTG at single implant sites. Clinical assessments and standardized measurements were performed at baseline after crown insertion and at 6 months, 1, 3, 5, 7.5, and 10 years. The primary outcome was mucosal thickness. Secondary outcomes included marginal bone levels (MBL), probing depth (PD), bleeding on probing (BOP), plaque control record, Pink Aesthetic Score (PES), OHIP-14 and buccal profilometric changes. Group comparisons were performed using mixed-effects and generalized estimating equation (GEE) models, which account for within-patient correlations due to repeated measurements and allow inclusion of all available data without requiring imputation for missing observations. RESULTS: Of the 20 originally enrolled patients, 10 (5 in the SCTG group and 5 in the VCMX group) were available for re-examination at 10 years. The adjusted between-group difference in mucosal thickness was -0.02 mm (95% CI -0.99 to 0.96). As the lower bound of the confidence interval remained above the prespecified non-inferiority margin of -1 mm, non-inferiority of VCMX was shown. Buccal contour changes were comparable during the early follow-up, while a trend toward a greater long-term contour decrease was observed in group VCMX (-0.31 mm [95% CI, -0.65 to 0.03]; p = 0.07). Mean PES values were 10.6 in the SCTG group and 9.6 in the VCMX group, with no significant between-group differences (p = 0.45). Both groups revealed high levels of oral health-related quality of life, with low median OHIP-14 scores (SCTG, 0.0; VCMX, 1.0; p = 0.26). CONCLUSION: These preliminary long-term findings showed no clinically relevant differences between SCTG and VCMX in terms of clinical, profilometric and patient-reported outcomes. While SCTG remains the reference standard, VCMX represents a less invasive alternative but with a slight tendency toward greater long-term contour reduction. CLINICAL SIGNIFICANCE: Volume-stable collagen matrices serve as a viable alternative to autogenous connective tissue grafts for peri-implant soft tissue volume augmentation, particularly in patients seeking a reduced morbidity, without compromising long-term clinical or aesthetic outcomes. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00017484.

Humans↗

PubMed2026

Influence of Immediate Post-Bleaching Polishing on Enamel Color, Morphology, and Sensitivity: A Randomized Clinical Trial.

OBJECTIVE: This study evaluated the influence of polishing on enamel color change after in-office bleaching treatment on tooth morphology and sensitivity. MATERIALS AND METHODS: A total of 50 volunteers were randomized into two groups (n = 25): in-office bleaching with 35% hydrogen peroxide gel for 45 min without polishing (GSEM) or with polishing (GP). Color analysis was performed four times, at the beginning of the starting line and immediately after the first, second, and third bleaching sessions with a spectrophotometer. A qualitative analysis of enamel morphology was performed under a scanning electron microscope. Tooth sensitivity was assessed daily using the Visual Analog Scale (α = 0.05). RESULTS: There was no statistically significant difference (p > 0.05) in tooth color change when comparing ΔE, ΔE00, and ΔWID between the groups. The enamel surface showed larger areas of irregularities and depressions in the GP group than in the GSEM group. There was no difference in tooth sensitivity (p > 0.05) between the groups. CONCLUSIONS: Polishing after whitening in the office does not change the color and sensitivity of the tooth but promotes greater changes in the morphology of the enamel, such as increased surface roughness. CLINICAL RELEVANCE: Polishing immediately after teeth whitening causes greater changes in enamel surface morphology.

Humans↗

PubMed2026

Evaluating Patient Satisfaction and Oral Health Impact Profile-14 (OHIP-14): A Multicenter Crossover Study Comparing Selective Pressure Impression Conventional Dentures with Mucostatic Digital Dentures.

PURPOSE: To compare patient satisfaction and oral health impact between individuals receiving complete dentures made by digital methods and those using conventional techniques. MATERIALS AND METHODS: In this randomized crossover clinical trial, 23 patients aged 40 years and older with completely edentulous arches were enrolled at three treatment centers. Each participant received two sets of complete dentures: one set created using conventional methods (selective pressure impression) and the other through digital techniques (mucostatic digital impression). The order of denture placement was randomized, with each set used for 4 weeks. A trained specialist administered treatments alongside research tools, including a general information questionnaire, a denture satisfaction survey, and the OHIP-14 interview tool. Statistical analysis was conducted using Mann-Whitney U test. RESULTS: Participants with digital dentures reported significantly higher satisfaction regarding treatment duration, comfort, confidence, chewing ability, esthetics, and overall satisfaction compared to those with conventional dentures. There were no significant differences in satisfaction concerning speech and pronunciation. Overall, the oral health impact on quality of life was similar between denture types, but participants indicated improved quality of life while using dentures compared to being edentulous. CONCLUSIONS: Patients with digital dentures exhibited greater satisfaction across various domains compared to those with conventional dentures, despite similar satisfaction levels in speech and pronunciation. The impact on quality of life was comparable between both types, as measured by the OHIP-14.

Humans↗

PubMed2026

Effects of Photobiomodulation Therapy in Lateral Luxation of Anterior Permanent Teeth: A Randomized, Double-Blind Clinical Trial.

BACKGROUND: Among the traumatic dental injuries (TDIs), lateral luxation may present poor prognosis due to frequent root resorption and consequent tooth loss. Photobiomodulation therapy (PBMT) modulates cellular activities (proliferation, differentiation, growth factor secretion) and may improve outcomes. OBJECTIVE: This randomized, double-blind, placebo-controlled trial evaluated PBMT (660 vs. 808 nm) for post-operative pain and pulp sensitivity recovery in lateral luxation of permanent anterior teeth. METHODS: Initially, 41 patients were included, with a total of 63 teeth traumatized by lateral luxation and were allocated to G1 (n = 21): Splinting + sham PBM (placebo), G2 (n = 21): Splinting + 808 nm infrared PBM and G3 (n = 21): Splinting + 660 nm red PBM. Four weekly sessions (3 J/point, 3 points) were administered. Pain (by numeric rating scale) and pulp sensitivity (by cold test) were assessed weekly. Pain was analyzed using the Kruskal-Wallis test, followed by multiple comparisons using Dunn's method with Bonferroni correction, and pulp sensitivity by a logistic regression model (p < 0.05). RESULTS: Three participants (total of 5 teeth) were excluded due to loss to follow-up. Fifty-eight teeth were analyzed (G1 = 21, G2 = 17, G3 = 20). Pain: All groups showed a significant reduction in pain over time (p < 0.001). Both G2 and G3 demonstrated a significantly greater reduction in pain compared to G1 (p < 0.001 and p = 0.026, respectively). No significant difference in pain reduction was observed between G2 and G3. Pulp sensitivity: G2 showed a significant improvement over time (p < 0.001), despite starting from a more unfavorable baseline. In contrast, no significant change in pulp sensitivity was observed for G1 or G3 between the initial and final assessments. CONCLUSION: Within the limitations of this clinical study, all intervention groups were effective in reducing pain in lateral luxation of permanent anterior teeth, with superior results for laser groups compared to the placebo. However, only the 808 nm laser irradiation protocol demonstrated a significant improvement in pulp sensitivity, suggesting it may offer a more complete therapeutic response.

Humans↗

PubMed2025

Effects of aerosol aging on composition and light-absorbance of nitrogen-containing organic compounds: Evidences from ultra-high-resolution mass spectrometry analysis.

Nitrogen-containing organic compounds (NOCs) are key components of particulate matter (PM), but their compositional evolution and light-absorbing properties during atmospheric aging remain poorly understood. In this study, ultra-high-performance liquid chromatography coupled with Orbitrap mass spectrometry was used to semi-quantitatively analyze 59 PM1 samples collected in Shanghai. NOCs accounted for 31 % and 64 % of the detected species in negative (ESI-) and positive (ESI+) ionization modes, respectively. Atmospheric aging significantly reduced the molecular diversity of polar organics, with both the number and mass concentration percentages of CHON- compounds showing significant negative correlations with aging degree. Van Krevelen analysis demonstrated a decrease in the number of carboxylic-rich alicyclic molecules and their CHON- contributions during the aging process (from 37.7 % in fresh samples to 21.2 % in aged samples). CHN+ compounds, a major NOCs group in ESI+ mode, also decreased with aging. Correlation analyses involving the Bep/(Bep+Bap) ratio, relative humidity, and mass absorption efficiency at 365 nm revealed a decline in light absorption capacity with aging, suggesting aqueous-phase oxidation as a dominant aging mechanism. CHON- and CHN+ compounds were identified as the principal light-absorbing constituents in PM1. This work provides new insights into the aging-induced transformations of NOCs in urban PM1, and their changing role in light absorption, highlighting the need for further investigation of the aging mechanisms of NOCs.

Aerosols↗

PubMed2026

Influence of nicotine on protein expression around hydrophilic osseointegrated implants: A proteomic study in male rats.

OBJECTIVE: To ensure the success of dental implant treatment, various factors must be considered, including osseointegration and systemic conditions. There is evidence in the literature that smokers may exhibit alterations in tissue healing, which can compromise the success of implant rehabilitation. Therefore, this study aimed to investigate the influence of nicotine on the protein profile of bone tissue around hydrophilic implants during the osseointegration process in rats. DESIGN: Bone tissue samples from the control and nicotine groups (n = 3 per group) were subjected to protein extraction, mass spectrometry, and bioinformatic analyses. Protein identification was performed using Proteome Discoverer 2.1 software and the SEQUEST algorithm, and the protein data were compared with those of a protein database of Rattus norvegicus obtained from UniProt. RESULTS: A total of 740 proteins were detected in both the control group and the nicotine-exposed group. Among them, the proteins biglycan, periostin and histone H4 were highlighted because of their higher abundance in the healthy implant group, while they were reduced in the nicotine-exposed group. CONCLUSIONS: Nicotine has the potential to alter the protein profile of bone tissue around hydrophilic implants during osseointegration, which may impair tissue remodeling and healing.

Animals↗

PubMed2026

Enhancement of secondary organic aerosol formation from isoprene photooxidation by ammonia.

Ammonia (NH3) can participate in atmospheric secondary organic aerosol (SOA) formation by reacting with organic acids and carbonyl compounds in particle phase, but its influence on the gas phase chemistry remains unclear. This study performed a series of smog chamber experiments to investigate the influence of NH3 on the formation of SOA from isoprene photooxidation by OH radicals. Both gas and particle phase products were measured with a series of state-of- art instruments including a nitrate ion chemical ionization mass spectrometer (nitrate-CIMS) and high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS). Our results showed that in the presence of NH3 SOA in the chamber significantly increased, along with an enhanced oxidation of isoprene. CIMS analysis further showed that NH3 in the chamber homogeneously reacts not only with gas-phase organic acids but also with gaseous low volatility oxygenated organic molecules (OOMs) to generate extremely low volatility and ultralow volatility NH3-OOMs clusters. Quantum chemical calculation showed that NH3 can spontaneously interact with OOMs to form NH3-OOMs clusters by forming hydrogen bonds with RCOOH, R-OOH, and R-OH. These clusters can promote new particles formation and particle growth through nucleation and condensation, directly enhancing the isoprene SOA production with a contribution of 78% to the enhanced SOA. Moreover, the formation of NH3-OOMs clusters also results in more isoprene consumed by OH radicals, indirectly increasing the SOA production with a contribution of 22 % to the enhanced SOA. Our work for the first time clarified a synergetic effect of NH3 on isoprene SOA formation, which should be accounted for by models.

Aerosols↗

PubMed2026

Biomass burning contributions to Mexico City's atmospheric CO2 estimated using a multi-isotope approach.

Fossil fuel combustion dominates anthropogenic emissions worldwide; however, special attention should be addressed to biomass burning, since it is an increasingly important contributor under warmer, drier fire-weather conditions exacerbated by climate change. These emissions could impact the atmospheric composition of heavily urbanized environments. To assess the influence of biomass burning, along with fossil fuels combustion and soil and plant respiration on Mexico City's atmospheric composition, we conducted a year-long (December 2023-December 2024) isotopic monitoring of atmospheric CO2, combining radiocarbon (Δ14C), CO2 stable isotopes (δ13C, δ18O), and CO/CO2 ratios. Once defined the isotopic signatures and the characteristic CO/CO2 that describe the sources, we performed Monte Carlo simulations under two tracer modalities (Δ14C + CO/CO2 and Δ14C + CO2 stable isotopes) for source apportionment. Results show that during the dry season, particularly in March-April, atmospheric Δ14C values approached and overlapped background levels despite Mexico City's fossil-fuel dominance, indicating enhanced non-fossil inputs. Moreover, backward HYSPLIT trajectories supported that these elevated Δ14C values coincided with regional wildfire activity. Monte Carlo results attributed up to ∼34 %-60 % of local CO2 to biomass burning in April, followed by March with contributions of ∼31 %-49 %. Since these biomass burning figures contrast with the official emissions inventory of Mexico City metropolitan area, which assigns <1 % of total CO2 emissions to biomass burning, this study could exhibit the emissions inventory underestimation of this source, and thus, the need to reassess and incorporate top-down isotopic constraints in fire-affected urban regions.

Mexico↗

PubMed2026

In situ product monitoring in heterogeneous reaction of gaseous trimethylamine on Fe2O3/Fe(NO3)3: Effect of environmental factor and particle property.

Gas-particle reactions represent an important atmospheric heterogeneous transformation process for organic amines (OAs). Environmental factors and particle properties may impact the gas-particle reaction products. Although the products from gas-particle reactions can be monitored by various in situ techniques, related data remain scarce. Here, the interfacial and gaseous products from the reaction of trimethylamine on Fe2O3/Fe(NO3)3 particles under light irradiation with mixed NO2, O2, SO2 and H2O were monitored using in-situ diffuse reflectance Fourier transform infrared spectroscopy and proton transfer reaction time-of-flight mass spectrometry. Dark reaction of gaseous trimethylamine on Fe2O3/Fe(NO3)3 generated two interfacial products types: N-containing ones (CH3NCH2, CH3NO2, (CH3)2NCHO, and CH3N(OH)CHO) and N-free ones (alcohols, aldehydes and acids), both accumulating with reaction progression. Light irradiation and O2 oxidation enhanced formation of these products, while NO2 promoted the production of CH3NO2 and (CH3)2NCHO. H2O and SO2 occupied the active sites of particles to inhibit the formation of all products. Compared to Fe(NO3)3, Fe2O3 showed absolute dominance in contribution to the formation of products. Considering the smaller particle size of Fe2O3 and excess Fe(NO3)3, the physical mixing of them reduced the generation of interfacial products. Furthermore, gaseous products of CH3OH, HCHO, CH3CHO, HCOOH and CH3COOH detection clarified the N-free interfacial products. The presence of Fe(NO3)3 inhibited the formation of HCOOH and favored the formation of CH3CHO in the gas phase. By combining product information with thermodynamic calculations, the heterogeneous reaction pathways of trimethylamine were tentatively proposed. These findings provide a guiding significance for the migration of OAs in real atmospheric environment.

Methylamines↗

PubMed2026

Variability and ozone formation potential of ambient non-methane hydrocarbons in a tropical semi-arid atmosphere of northwest India.

We present first-time measurements of twenty-six ambient non-methane hydrocarbons (NMHCs; C2-C8), including isoprene (C5H8), at a semi-arid site in northwest India (Ajmer; 26.45°N, 74.64°E), during January 2022-December 2023. Ambient samples were analyzed using a thermal desorption gas chromatography system equipped with dual flame ionization detectors. Daily total NMHC levels ranged from 6 ppbV to >100 ppbV. Most NMHCs, except isoprene, toluene, ethylbenzene, m-xylene and o-xylene, exhibited the highest levels in winter and the lowest in the monsoon. In contrast, others were highest in the pre-monsoon and toluene was highest during monsoon. These variations reflect the combined influence of emissions, chemistry and meteorology. Toluene and o-xylene were the dominant NMHCs (25 %-67 %). Correlation analyses indicated major contributions from liquefied petroleum gas (LPG) and vehicular emissions, with additional influence from urban and oil and natural gas activities. Compared with other Indian sites, NMHCs levels at Ajmer were 2-5 times lower than Ahmedabad and Udaipur and 10 times lower than Delhi. The total ozone formation potential was highest in the monsoon (about 175 ppbV) and lowest in the post-monsoon (about 55 ppbV), with dominance of o-xylene (24 %-33 %) and toluene (8 %-37 %). Propylene-equivalent concentrations were highest in the pre-monsoon (30.23 ppb C) and lowest in the post-monsoon (7.28 ppb C). Similarly, OH reactivity was highest in the pre-monsoon (19.58 s⁻¹) and lowest in the post-monsoon (4.71 s⁻¹), dominated by benzene and toluene. These findings emphasize the importance of NMHC chemistry in a climatically sensitive region and highlight the need for their continuous monitoring.

India↗

PubMed2026

Comparison of conventional and micro-surgical techniques for gingival recession using collagen matrix: Randomised controlled split-mouth clinical trial.

BACKGROUND: The present study aimed to determine the effectiveness of the microsurgical approach in treating gingival recession with collagen matrix by comparing it with Conventional surgery in terms of clinical and patient-centered outcomes. METHODS: A total of 29 patients with bilateral gingival recession in the maxillary canine and/or premolar region were selected. After randomisation, bilateral recession sites were grouped into the test group (Microsurgery under 3.5 X magnification) and the control group (Conventional surgery). All the clinical and patient-reported parameters were recorded at baseline, 1, 3 and 6 months. RESULTS: Both groups showed statistically significant differences in terms of reduction in gingival recession height (GRH), gingival recession width (GRW), clinical attachment level gain (CAL gain), increase in keratinized tissue thickness (KTT) and keratinized tissue width (KTW) after 6 months. But intergroup comparison showed no significant difference in terms of clinical parameters. The only significant difference was noted in terms of patient-centred parameters (Patient satisfactory score, Hypersensitivity score, Root aesthetic scores), which favoured the microsurgical group. CONCLUSIONS: Both groups demonstrated comparable clinical improvement; However, Patient-centred parameters were significantly better with the Microsurgical approach. Selection of the surgical approach should balance patient needs with practical considerations like cost, time, and clinician proficiency.

Adult↗