Transfer Learning of Full Molecular Weight Distributions via High-Throughput Computer-Controlled Polymerization.

The skew and shape of the molecular weight distribution (MWD) of polymers have a significant impact on polymer physical properties. Standard summary metrics statistically derived from the MWD only provide an incomplete picture of the polymer MWD. Machine learning (ML) methods coupled with high-throughput experimentation (HTE) could potentially allow for the prediction of the entire polymer MWD without information loss. In our work, we demonstrate a computer-controlled HTE platform that is able to run up to 8 unique variable conditions in parallel for the free radical polymerization of styrene. The segmented-flow HTE system was equipped with an inline Raman spectrometer and offline size exclusion chromatography (SEC) to obtain time-dependent conversion and MWD, respectively. Using ML forward models, we first predict monomer conversion, intrinsically learning varying polymerization kinetics that change for each experimental condition. In addition, we predict entire MWDs including the skew and shape as well as SHAP analysis to interpret the dependence on reagent concentrations and reaction time. We then used a transfer learning approach to use the data from our high-throughput flow reactor to predict batch polymerization MWDs with only three additional data points. Overall, we demonstrate that the combination of HTE and ML provides a high level of predictive accuracy in determining polymerization outcomes. Transfer learning can allow exploration outside existing parameter spaces efficiently, providing polymer chemists with the ability to target the synthesis of polymers with desired properties.

Control of Drug-Excipient Particle Attributes with Droplet Microfluidic-based Extractive Solidification Enables Improved Powder Rheology.

PURPOSE: Industrial implementation of continuous oral solid dosage form manufacturing has been impeded by the poor powder flow properties of many active pharmaceutical ingredients (APIs). Microfluidic droplet-based particle synthesis is an emerging particle engineering technique that enables the production of neat or composite microparticles with precise control over key attributes that affect powder flowability, such as particle size distribution, particle morphology, composition, and the API's polymorphic form. However, the powder properties of these microparticles have not been well-studied due to the limited mass throughputs of available platforms. In this work, we produce spherical API and API-composite microparticles at high mass throughputs, enabling characterization and comparison of the bulk powder flow properties of these materials and greater understanding of how particle-scale attributes correlate with powder rheology. METHODS: A multi-channel emulsification device and an extractive droplet-based method are harnessed to synthesize spherical API and API-excipient particles of artemether. As-received API and API crystallized in the absence of droplet confinement are used as control cases. Particle attributes are characterized for each material and correlated with a comprehensive series of powder rheology tests. RESULTS: The droplet-based processed artemether particles are observed to be more flowable, less cohesive, and less compressible than conventionally synthesized artemether powder. Co-processing the API with polycaprolactone to produce composite microparticles reduces the friction of the powder on stainless steel, a common equipment material. CONCLUSIONS: Droplet-based extractive solidification is an attractive particle engineering technique for improving powder processing and may aid in the implementation of continuous solid dosage form manufacturing.

Alveolar Osteitis: Patient's Compliance with Post-extraction Instructions Following Permanent Teeth Extraction.

AIM: The study aims to evaluate the patients' compliance with post-extraction instructions to prevent the development of alveolar osteitis and keep the health of the socket. Alveolar osteitis "Dry socket" is considered one of the most common complications after extraction. MATERIALS AND METHODS: Study was based on an observational cross-sectional design involving 201 subjects (individuals). The subjects were evaluated via a survey questionnaire and clinical examination after obtaining their verbal and written consent. The study questionnaire was divided into the following sections; section one records the demographic data about the subject while the second section focuses on self-assessment mainly regarding compliance with post-extraction instructions and pain. RESULTS: A total number of patients included in the study was 201, 122 (60.7%) male and 79 (39.3%) female with an age of more than 18 years. No statistically significant association was reported between a medical condition and dry socket. Out of 201 patients came for clinical examination, 89 felt pain at the site of extraction at different period started from the day of extraction till the day of examination with various pain intensity. Females were the most to feel pain after tooth extraction with 78%. Regarding prevalence, 14 (7%) patients reported having dry socket and poor socket status. A statistically significant association of non-complying patients with the incidence of the dry socket was observed for a wide range of age (18 to 40 years) Conclusion: The study showed a high degree of association between the incidence of dry socket cases for patients with poor compliance with post-extraction instruction. A strong relation was observed between the patients who felt pain and their gender (females) Clinical significance: Based on the findings of the present study, we recommend the need to properly educate patients on the effect of compliance and the various complications and factors affecting the socket status after tooth extraction due to non-compliance.

Short-term, nonsurgical periodontal therapy boosts interleukin-12 levels and reduces oral cancer risk.

BACKGROUND: Cytokines, including interleukin-12 (IL-12), are proteins that regulate cell survival, proliferation, differentiation, and function. IL-12 is a heterodimeric proinflammatory cytokine. It possesses tumoricidal properties and promotes M1 macrophage polarization and IFN-γ production by T helper (Th1) cells, which in turn stimulates the antitumor cytotoxic cluster of eight positive (CD8+) and natural killer cells, therefore activating an effector immune response against tumor cells. MATERIALS AND METHODS: Herein, the IL-2 levels of 60 patients with generalized chronic periodontitis (GCP) were assessed. Plaque index, gingival index, pocket probing depth, bleeding on probing percentage (BOP %), and clinical attachment loss were the clinical indicators reported. RESULTS: Patients with GCP in the pretreatment group had substantially lower mean IL-12 levels than those in the post-treatment group. Short-term, nonsurgical treatment (NST) considerably improved periodontal indices and increased IL-12 levels, thereby reducing oral cancer risk. CONCLUSION: NST is a cost-effective and accessible cancer prevention procedure for general dentists.

Assessment of Changes in Craniofacial Structures, Bite Force and Periodontal Status Following Fixed Functional Appliance Therapy.

Objective: The aim of this study was to determine the effect of Forsus Fatigue Resistant Device (FRD) appliance on craniofacial structures, bite force and periodontal status in Class II malocclusion patients. Methods: In this prospective interventional follow-up study, thirteen (13) Class II Division 1 patients in their post-adolescent age group with average age of 17.10 ± 1.63 year was treated with Forsus FRD. They were assessed for craniofacial changes, bite force and periodontal status at baseline, after alignment and leveling, after removal of FRD. Results: Improvement in soft tissue profile was due to significant dentoalveolar changes. There were significant decreases in overjet, overbite, reference line to upper first molar, H angle (p<0.001) and significant increases in upper lip to E-line, reference line to lower molar and angular measurements like nasolabial angle, U1 to SN plane, Incisor Mandibular Plane Angle (p<0.001). The bite force was significantly decreased on the molar and the incisor region (p<0.001). A significant increase in plaque index (PI), gingival index (GI), probing pocket depth was noticed without any significant clinical attachment loss. Conclusion: Class II correction with Forsus FRD appliance was mainly due to significant dentoalveolar changes. Skeletal changes were non-significant. A decrease in the bite force was found with FRD. The magnitude of bite force was more in males compared with females. The increase in GI, PI, pocket probing depth implies the necessity of oral hygiene and plaque control measures. However, there was no significant change in clinical attachment level.

Knowledge and Perception of Orthodontic Treatment among General and Non-Orthodontic Dental Specialists: A Comparative Study.

The objective of this study is to discover any possible association of gender or practitioner classification with orthodontic knowledge and attitudes towards orthodontic treatment. Descriptive cross-sectional research was conducted on two groups of dentists in the Ha'il region of Saudi Arabia. Group I included general practitioners, while Group II had non-orthodontic specialists. The findings suggest a statistically significant (p < 0.05) difference between the knowledge and attitudes of general practitioners and non-orthodontic specialists. Independent two tailed t-scores for difference in Knowledge (t-score = 3.19919, p = 0.003) and Attitude (t-score = 2.16314, p = 0.048319), highlight significant disparities in the knowledge and attitudes of general practitioners and non-orthodontic specialists. However, no statistically significant difference was observed in terms of knowledge and attitudes based on gender differences. This study captures and highlights subtle information that is very significant in dealing with critically important orthodontics issues. The study suggests that it is possible that a non-orthodontic specialist may suggest an altogether different line of treatment with different consequences when compared to a general practitioner and vice versa. This may result in unwanted, permanent orthodontic effects, highlighting the significance of the early stage of orthodontic treatment awareness. This research reveals disparities between the perceptions of general practitioners and non-orthodontic specialists about the stage and relevance of orthodontic treatment. It is strongly advised to see an orthodontic expert rather than a general practitioner or non-orthodontic specialist for orthodontic issues.

The effect of non-surgical periodontal therapy on salivary IL-6 levels in patients with moderate to severe generalized chronic periodontitis.

BACKGROUND: Gene regulation of IL-6 is characterized by the presence of inflammatory cytokines, bacterial products, viral infection, and activation of the diacylglycerol-, cyclic AMP-, or Ca + + -activated signal transduction pathways. AIM: Scaling and root planning (SRP), a non-surgical periodontal therapy, was studied in connection to several clinical parameters for its effect on salivary IL-6 levels in patients with generalized chronic periodontitis. METHODS: For this study, a total of 60 GCP patients were included. Plaque index (PI), gingival index (GI), pocket probing depth (PPD), bleeding on probing percentage (BOP%), and clinical attachment loss were among the clinical indicators covered (CAL). RESULTS: Following SRP, mean IL-6 levels in patients with GCP were significantly higher in the pre-treatment group (2.93 5.17 pg/ml; p 0.05) than in the posttreatment group (5.78 8.26 pg/ml; baseline). Pre- and post-treatment IL-6 levels for PI (pre), BOP percent (pre/post), GI (post), and PPD were found to be positively correlated (post). In patients with GCP, the study showed a statistically significant correlation between periodontal metrics and salivary IL-6. CONCLUSIONS: Changes in periodontal indices and IL-6 levels that are statistically significant over time indicate that non-surgical treatment is effective, and IL-6 can be regarded as a potent disease activity marker.

Comparative assessment of periodontal status and genotoxicity in orthodontic patients on fixed mechanotherapy with and without adjunct chlorhexidine mouthrinse: A randomized control clinical trial.

Background: Adjunct chlorhexidine mouthrinse is used routinely in orthodontic clinical practice for plaque control. However, chlorhexidine has genotoxic effects on the oral cells. Moreover, orthodontic appliance leach Ni, Cr metals ions into saliva causing toxicity of surrounding mucosa. Hence, the aim of the study was to assess the periodontal status and genotoxicity in orthodontic patients on fixed mechanotherapy with and without adjunct chlorhexidine using micronucleus (MN) test. Materials and Methods: A randomized control clinical trial was conducted in 30 patients who were on fixed mechanotherapy. The patients were randomly assigned into two treatment groups; Group-A (Control Group): Included 15 patients who are on fixed orthodontic therapy with mechanical plaque control measures only., Group-B (Experimental Group:) included 15 patients on fixed orthodontic therapy with mechanical plaque control and adjunct chlorhexidine mouthrinse (0.2%) for 2 weeks. Periodontal status and genotoxicity using MN test were done at following time points; T0: Just before start of the orthodontic treatment., T1: 2 weeks after start of the orthodontic treatment., T2: 6 weeks after start of the orthodontic treatment., T3: 12 weeks after start of the orthodontic treatment. Results: Plaque index (PI) and bleeding on probing (BOP) were significantly decreased in Group B as compared to Group A in the time intervals; T0-T2, T0-T3, T1-T3 (P < 0.05). Probing pocket depth (PPD) and Clinical attachment level (CAL) showed no significant change in both the groups. The genotoxicity assessed by MN test was significantly increased in Group B than Group A at time intervals; T0-T1, T0-T2 and T0-T3. Conclusion: Adjunct chlorhexidine resulted in decreased PI and BOP scores but nonsignificant change in PPD and CAL. However, the genotoxicity increased significantly in both the groups but more with adjunct chlorhexidine.

Gingival squamous cell carcinoma masquerading as necrotizing ulcerative periodontitis.

Necrotizing ulcerative periodontitis (NUP) is a painful and debilitating condition seen mostly in an immunocompromised state. Although squamous cell carcinoma (SCC) on gingiva is not uncommon, its presentation as a benign necrotizing lesion on gingiva is rare. Such presentations may lead to delayed diagnosis and poor prognosis. This report describes a case of a 34-year-old male presenting clinically with NUP around mandibular posterior teeth. Clinical features were misleading, but the histological findings established the diagnosis of well-differentiated SCC. Immunohistochemistry also showed features of epithelial-mesenchymal transition with decreased expression of E-cadherin and increased vimentin expression showing local invasion and metastasis. The patient was referred to the oncology department for evaluation of possible metastasis and further management of carcinoma.

Periodontal status associated with dual habits of smoking and smokeless tobacco use: A cross-sectional study in young adults.

Background: Tobacco smoke is an established risk factor for periodontitis. However, few studies have evaluated the periodontal status of smokeless tobacco (SLT) users, while that of individuals with dual habits has largely been unexplored. Therefore, the current study aimed to find if the periodontal status in individuals with dual habits of smoking and SLT use is different from those with any single habit. Methods: Four groups (A: exclusive smokers, B: exclusive tobacco chewers, C: individuals with dual habits, and D: non-users of tobacco), each comprising 75 males in the age group of 20 to 35 years, were selected. Along with the history of tobacco use, a modified oral hygiene index (OHI), gingival index (GI), probing depth (PD), and the number of teeth with gingival recession (GR) were recorded. The data were assessed using the Chi-squared test, one-way ANOVA, and logistic regression. Statistical significance was set at P<0.05. Results: Group C exhibited the highest mean OHI scores, with 94.66% of participants having poor oral hygiene (OHI>3.0). The prevalence of severe gingivitis (GI>2.0) was significantly lower among exclusive smokers (group A) and those with dual habits (group C) compared to the other two groups. As much as 60% of group C participants had average PD in the range of 4-6 mm, while deeper average PD (>6 mm) was most common among smokers. The highest risk of having a tooth with GR was also associated with the dual habit (OR = 4.33, 95% CI = 3.24 - 5.76) compared with the non-users. Conclusion: While both forms of tobacco were associated with poor periodontal status, the additive effect of smoking and SLT use was evident in almost all the parameters, more so with poor oral hygiene and the prevalence of gingival recession. These findings emphasize that individuals with dual habits have an additional risk for periodontal destruction.

Twin-Screw Extrusion Process to Produce Renewable Fiberboards.

A versatile twin-screw extrusion process to provide an efficient thermo-mechano-chemical pre-treatment on lignocellulosic biomass before using it as source of mechanical reinforcement in fully bio-based fiberboards was developed. Various lignocellulosic crop by-products have already been successfully pre-treated through this process, e.g., cereal straws (especially rice), coriander straw, shives from oleaginous flax straw, and bark of both amaranth and sunflower stems. The extrusion process results in a marked increase in the average fiber aspect ratio, leading to improved mechanical properties of fiberboards. The twin-screw extruder can also be fitted with a filtration module at the end of the barrel. The continuous extraction of various chemicals (e.g., free sugars, hemicelluloses, volatiles from essential oil fractions, etc.) from the lignocellulosic substrate, and the fiber refining can, therefore, be performed simultaneously. The extruder can also be used for its mixing ability: a natural binder (e.g., Organosolv lignins, protein-based oilcakes, starch, etc.) can be added to the refined fibers at the end of the screw profile. The obtained premix is ready to be molded through hot pressing, with the natural binder contributing to fiberboard cohesion. Such a combined process in a single extruder pass improves the production time, production cost, and may lead to reduction in plant production size. Because all the operations are performed in a single step, fiber morphology is better preserved, thanks to a reduced residence time of the material inside the extruder, resulting in enhanced material performances. Such one-step extrusion operation may be at the origin of a valuable industrial process intensification. Compared to commercial wood-based materials, these fully bio-based fiberboards do not emit any formaldehyde, and they could find various applications, e.g., intermediate containers, furniture, domestic flooring, shelving, general construction, etc.

Prioritization and characterization of validated biofilm blockers targeting glucosyltransferase C of Streptococcus mutans.

To date, several Glucosyltransferase C (GtfC) inhibitors have been identified and experimentally validated. All these inhibitors have been validated at different experimental conditions like degree of purity, animal models, kinetic conditions, experimental environment etc.; and most of these inhibitors (ligands) proved to be quite effective in their respective validation environment. However, due to varied experimental validation conditions, and absence of molecular interaction data, there is no way to prioritize these validated ligands for their inhibition potential against GtfC. The present study is a novel attempt of comparative evaluation of the interaction of the validated ligands on a single platform and under similar conditions with a dual objective, i.e. ligand prioritization for their respective inhibitory potential and elucidation of the involved unknown molecular interactions. Carbohydrate derivatives (6-Deoxy sucrose and Trichloro-galactosucrose) were identified as the most promising GtfC inhibitors. In addition, Asp588, Trp517, and Asn481 amino acid residues of the domain A1 proved vital for the inhibitory effect. The study highlights the importance of the comparative analysis of the validated ligands in order to identify the most promising leads for drug discovery against dental caries.

UV-defined flat PDMS stamps suitable for microcontact printing.

We report a simple method of creating well-defined micropatterns on the surface of a flat PDMS stamp, making it suitable for microcontact printing of proteins. This method only requires a UV lamp (254 nm) and a TEM grid (as a photomask) to modify the surface of PDMS for creating desired micropatterns. By using the UV-modified stamp, a printed protein micropattern that resembles the original TEM grid can be obtained. Surprisingly, unlike the oxygen-plasma-treated PDMS, the UV-modified flat stamp is also long-lasting (>1 week). The method reported herein is very economical for microcontact printing applications because expensive silicon masters and microstructured PDMS are no longer required.

Knowledge of dental faculty in gulf cooperation council states of multiple-choice questions' item writing flaws.

Multiple-Choice Questions provide an objective cost/time effective assessment. Deviation from appropriate question writing structural guidelines will most probably result in commonly ignored multiple-choice questions writing flaws, influencing the ability of the assessment to measure students' cognitive levels thereby seriously affecting students' academic performance outcome measures. To gauge the knowledge of multiple-choice question items writing flaws in dental faculty working at colleges in Gulf Cooperation Council (GCC) countries. A cross-sectional short online Survey MonkeyTM multiple-choice questions-based questionnaire was disseminated to dental faculty working in GCC countries during the academic year 2018/2019. The questionnaire included five test incorrect (flawed) multiple-choice questions and one correct control question. The participants were asked to identify flawed multiple-choice question items from the known 14 items writing flaws. Out of a total of 460 faculty, 216 respondents completed the questionnaires, 132 (61.1%) were from Saudi Arabia, while numbers of participants from United Arab Emirates, Kuwait and Oman were 59 (27.3), 14 (6.5%) and 11 (5.1%) respectively. Majority of participants were male (n = 141, 65.9%) compared to 73 females (34.1%). Eighty percent of the participants possessed more than five years of teaching experience. Assistant professors constituted the majority (43.3%) of the academic positions participating in this study. The overall fail rate ranged from 76.3% to 98.1% and almost 2/3rds of the participants were unable to identify one or more of the flawed item(s). No significant association was observed between the demographics (age, region, academic position and specialty) and knowledge except that of participant's gender (p < 0.009). GCC dental faculty demonstrated below average knowledge of multiple-choice question items writing flaws. Training and workshops are needed to ensure substantial exposure to proper multiple-choice question items construction standards.

The roles and regulation of TBX3 in development and disease.

TBX3, a member of the ancient and evolutionary conserved T-box transcription factor family, is a critical developmental regulator of several structures including the heart, mammary glands, limbs and lungs. Indeed, mutations in the human TBX3 lead to ulnar mammary syndrome which is characterized by several clinical malformations including hypoplasia of the mammary and apocrine glands, defects of the upper limb, areola, dental structures, heart and genitalia. In contrast, TBX3 has no known function in adult tissues but is frequently overexpressed in a wide range of epithelial and mesenchymal derived cancers. This overexpression greatly impacts several hallmarks of cancer including bypass of senescence, apoptosis and anoikis, promotion of proliferation, tumour formation, angiogenesis, invasion and metastatic capabilities as well as cancer stem cell expansion. The debilitating consequences of having too little or too much TBX3 suggest that its expression levels need to be tightly regulated. While we have a reasonable understanding of the mutations that result in low levels of functional TBX3 during development, very little is known about the factors responsible for the overexpression of TBX3 in cancer. Furthermore, given the plethora of oncogenic processes that TBX3 impacts, it must be regulating several target genes but to date only a few have been identified and characterised. Interestingly, while there is compelling evidence to support oncogenic roles for TBX3, a few studies have indicated that it may also have tumour suppressor functions in certain contexts. Together, the diverse functional elasticity of TBX3 in development and cancer is thought to involve, in part, the protein partners that it interacts with and this area of research has recently received some attention. This review provides an insight into the significance of TBX3 in development and cancer and identifies research gaps that need to be explored to shed more light on this transcription factor.

An optimised saliva collection method to produce high-yield, high-quality RNA for translational research.

Saliva represents an ideal matrix for diagnostic biomarker development as it is readily available and requires no invasive collection procedures. However, salivary RNA is labile and rapidly degrades. Previous attempts to isolate RNA from saliva have yielded poor quality and low concentrations. Here we compare collection and processing methods and propose an approach for future studies. The effects of RNA stabilisers, storage temperatures, length of storage and fasting windows were investigated on pooled saliva samples from healthy volunteers. Isolated RNA was assessed for concentration and quality. Bacterial growth was investigated through RT-PCR using bacterial and human primers. Optimal conditions were implemented and quality controlled in a clinical setting. The addition of RNAlater increased mean RNA yield from 4912 ng/µl to 15,473 ng and RNA Integrity Number (RIN) from 4.5 to 7.0. No significant changes to RNA yield were observed for storage at room temperature beyond 1 day or at -80 °C. Bacterial growth did not occur in samples stored at ambient temperature for up to a week. There was a trend towards higher RNA concentration when saliva was collected after overnight fasting but no effect on RIN. In the clinic, RNA yields of 6307 ng and RINs of 3.9 were achieved, improving on previous reports. The method we describe here is a robust, clinically feasible saliva collection method using preservative that gives high concentrations and improved RINs compared to saliva collected without preservative.

Healing of self-inflicted thermal injury of palatal mucosa by low-level laser therapy.

Self-inflicted injury to oral mucosa is a rare entity. These injuries can be premeditated, accidental, or can result from an abnormal habit. These uncommon gingival injuries can sometimes test the clinician's diagnostic abilities as well as treatment planning skills. In conventional treatment, removal of etiology and application of topical drugs is usually sufficient for healing. However, some cases require alternative or adjunctive wound healing methods. Low-level laser therapy (LLLT) has been reported to be effective in pain management and improvement in wound healing through promotion, fortification, and commissioning of cellular cycle to generate productive and substitute cells. This report presents a case of 25-year-old female with complaints of a painful, nonhealing wound on the palate for last 6 months. She had an unusual habit of keeping burning matchsticks in her mouth. Although she had quit the habit 2 months ago after psychiatric counseling, the wound on her palate did not show any improvement in symptoms. Based on the history and clinical findings, diagnosis of chronic wound by self-inflicted thermal injury was made. LLLT was administered on the wound every 48 hours for next 10 days. The burn wound healed completely after five applications of LLLT.

Role of bolA and rpoS genes in biofilm formation and adherence pattern by Escherichia coli K-12 MG1655 on polypropylene, stainless steel, and silicone surfaces.

Escherichia coli has developed sophisticated means to sense, respond, and adapt in stressed environment. It has served as a model organism for studies in molecular genetics and physiology since the 1960s. Stress response genes are induced whenever a cell needs to adapt and survive under unfavorable growth conditions. Two of the possible important genes are rpoS and bolA. The rpoS gene has been known as the alternative sigma (σ) factor, which controls the expression of a large number of genes, which are involved in responses to various stress factors as well as transition to stationary phase from exponential form of growth. Morphogene bolA response to stressed environment leads to round morphology of E. coli cells, but little is known about its involvement in biofilms and its development or maintenance. This study has been undertaken to address the adherence pattern and formation of biofilms by E. coli on stainless steel, polypropylene, and silicone surfaces after 24 h of growth at 37 °C. Scanning electron microscopy was used for direct examination of the cell attachment and biofilm formation on various surfaces and it was found that, in the presence of bolA, E. coli cells were able to attach to the stainless steel and silicone very well. By contrast, polypropylene surface was not found to be attractive for E. coli cells. This indicates that bolA responded and can play a major role in the presence and absence of rpoS in cell attachment.

Genotoxic assessment of chlorhexidine mouthwash on exfoliated buccal epithelial cells in chronic gingivitis patients.

BACKGROUND: Chlorhexidine (CHX) is the gold standard of all chemical plaque control agents and the most commonly prescribed mouthwash. However, several studies have shown cytotoxic and genotoxic effects of CHX on various eukaryotic cells. In this study, we have used micronuclei as a biomarker of DNA damage in buccal epithelial cells of chronic gingivitis patients who were given adjunct 0.2% CHX for plaque control. MATERIALS AND METHODS: Chronic gingivitis patients who were exclusively on mechanical plaque control methods were taken as control (Group A) (n = 101), and chronic gingivitis patients who along with mechanical plaque control measures were taking 0.2% chlorhexidine mouthwash as adjunct were taken as cases (Group B) (n = 255). The Group B was further divided into 5 subgroups (B1, B2, B3, B4, B5) (n = 51) on increasing duration of usage of CHX from ≤1 week to 24 weeks. Buccal epithelial cells were gently scrapped from the buccal mucosa using soft toothbrush. The epithelial cells were collected in buffer solution and centrifuged at 8000 rpm for 5 min. The buccal epithelial cells were air dried, fixed, and stained with 5% Giemsa stain on preheated glass microscopic slides and observed under microscope to screen 2000 nucleated cells per individual for number of micronucleated cells and micronuclei as genotoxic measure. RESULTS: The mean number of micronucleated cells was found to be 0.41 ± 0.71 for Group A as compared values ranging from 1.65 ± 2.09 (Group B1) to 11.7 ± 1.87 (Group B5) in different subgroups of Group B, and similarly, the mean number of micronuclei was found to be 0.48 ± 0.80 for Group A as compared to values ranging from 2.57 ± 1.64 (Group B1) to 14.5 ± 2.49 (Group B5) in different subgroups of Group B using analysis of variance (P < 0.001). CONCLUSION: We conclude that CHX mouthwash is genotoxic to buccal epithelial cells and there is incremental trend in genotoxicity as the duration of usage is increased.

Co-micellization behavior of triblock copolymers in the presence of hydrophobic drug molecules: A simulation study.

Dissipative particle dynamics simulation of bead-spring chains is applied to study co-micellization, micellar and drug loading properties of binary triblock copolymer systems to seek a better understanding on selection and utilization of polymer mixtures to improve the drug encapsulation efficiency and loading capacity. Co-micellization is found to still occur in the presence of drug; pure and mixed micelles coexist with some devoid of any drug due to their significantly lower aggregation numbers. The drug encapsulation enlarges the micelle cores, and may induce a morphology transition from spherical to ellipsoidal or rod-like micelles. For the binary mixture of polymer species with a considerable difference in chain length, the majority of the shorter chains are located near the periphery of the hydrophobic core, because they prefer the loop conformation so as to join the micelles in the co-micellization process. Increasing the drug concentration causes more chains to become looped to facilitate the formation of larger micelles for drug accommodation.