Therapeutic Potential of Nanocarrier Mediated Delivery of Peptides for Wound Healing: Current Status, Challenges and Future Prospective.

Wound healing presents a complex physiological process that involves a sequence of events orchestrated by various cellular and molecular mechanisms. In recent years, there has been growing interest in leveraging nanomaterials and peptides to enhance wound healing outcomes. Nanocarriers offer unique properties such as high surface area-to-volume ratio, tunable physicochemical characteristics, and the ability to deliver therapeutic agents in a controlled manner. Similarly, peptides, with their diverse biological activities and low immunogenicity, hold great promise as therapeutics in wound healing applications. In this review, authors explore the potential of peptides as bioactive components in wound healing formulations, focusing on their antimicrobial, anti-inflammatory, and pro-regenerative properties. Despite the significant progress made in this field, several challenges remain, including the need for standardized characterization methods, optimization of biocompatibility and safety profiles, and translation from bench to bedside. Furthermore, developing multifunctional nanomaterial-peptide hybrid systems represents promising avenues for future research. Overall, the integration of nanomaterials made up of natural or synthetic polymers with peptide-based formulations holds tremendous therapeutic potential in advancing the field of wound healing and improving clinical outcomes for patients with acute and chronic wounds.

Comparative Evaluation of Effect of Lasers and Biodentine in Dentine Regeneration: A Clinical Study.

AIM: To compare and evaluate the effect of different liners separately and in combination with lasers that is resin modified glass-ionomer cement (RMGIC), Laser+RMGIC, Biodentine, Laser+Biodentinein the treatment of deep carious lesions. MATERIALS AND METHODS: Forty patients with deep caries indicated for pulp capping were selected. Curative procedure including the cavity preparation with maximal removal of softened dentine using spoon excavator, slow speed handpiece with round burs was performed. Patients were divided into four groups with 10 patients in each group In group A RMGIC liner, group B laser biostimulation followed by RMGIC liner, group C biodentine liner, group D laser biostimulation followed by Biodentine liner were placed in the cavity after caries removal. Cavities were temporarily restored with IRM for 8 weeks. After 8 weeks, liners in each group were removed, and cavities were permanently restored lower half of the cavity with a layer of flowable Z350 XT composite, and then the remaining half of the cavity with P60 filled composites (3 M ESPE, USA) in all the groups. The observation period was 12 months. RESULTS: All the patients showed a positive response to cold test and electric pulp test at 3 months, 6 months, 12 months follow-up. In group A (RMGIC) two patients and in group B (Laser+Biodentine) three patients did not return back for the follow-up. To standardize the samples, seven patients were selected from each group with a total of 28 samples included in the study (n = 7) and statistical analysis was done using analysis of variance (ANOVA) test. The mean for the total amount of dentine deposited after 12 months was highest in: Group D-(Laser+Biodenitne) 0.32 mm > Group C-(Biodentine) 0.25 mm > Group B-(Laser+RMGIC) 0.10 > Group A-(RMGIC) 0.07 mm Conclusion: Within the limitation of the present study the following conclusion was drawn: • Lasers and biodentine are good indirect pulp capping agents • Laser has an additional effect on the tertiary dentine formation. CLINICAL SIGNIFICANCE: Lasers with antibacterial effect penetrate into dentinal tubules and accelerate the rate of dentin bridge formation in deep carious lesions.

Are there any factors affecting the outcome of endoscopic sclerotherapy in filarial chyluria? A prospective study.

INTRODUCTION: Filarial chyluria is a frequent problem in India. While endoscopic therapy is the mainstay of treatment, it is not always successful. We aimed to determine parameters that affect outcomes of endoscopic sclerotherapy for filarial chyluria (FC). METHODS: Prospectively maintained data of FC patients who received endoscopic sclerotherapy between June 2011 and March 2015 were analyzed. Sclerotherapy included either povidone-iodine (0.1%) or silver nitrate (1%). The parameters recorded included clinical evaluation, urinary triglyceride (TG)/cholesterol, sclerotherapy treatment, and follow-up. RESULTS: One hundred and fifty-seven patients (male: female, 104:53) with a mean age (± standard deviation [SD]) 41.12 ± 13.68 years underwent endoscopic sclerotherapy. Grade II (68.88%) chyluria was a most common presentation followed by Grade III (25.69%). One hundred and forty-four patients responded whereas six patients failed to respond; another seven were lost to follow up, and twenty patients had recurrence. Overall success rate was 86.11%. Baseline urinary TG (mean ± SD) between success and recurrence group was 195.51 ± 164.73 mg/dl and 652.65 ± 62.55 mg/dl and cholesterol (mean ± SD) was 16.99 ± 10.08 mg/dl and 89.07 ± 39.87 mg/dl, respectively. Patient with urinary TGs >300 mg/dl and urinary cholesterol >30 mg/dl had 3.2 and 1.3 times higher chance to have recurrence after endoscopic sclerotherapy, respectively. Choice of sclerosing agent (silver nitrate 1% versus povidone-iodine 0.1%) had no difference in success rate, but silver nitrate had slightly higher complications rate (25% vs. 20%). A higher number of instillations (>3) was associated with better success rate. Majority of the complications were either Clavien Grade 1 or 2. CONCLUSIONS: The factors predicting recurrence were higher clinical grade, higher number of pretreatment courses, and high urinary TG and cholesterol.

Nanotechnology in Orthodontics: Unveiling Pain Mechanisms, Innovations, and Future Prospects of Nanomaterials in Drug Delivery.

Orthodontic pain is characterized by sensations of tingling, tooth discomfort, and intolerance. According to the oral health report, over forty percent of children and adolescents have undergone orthodontic treatment. The efficacy of orthodontic treatment involving braces can be compromised by the diverse levels of discomfort and suffering experienced by patients, leading to suboptimal treatment outcomes and reduced patient adherence. Nanotechnology has entered all areas of science and technology. This review provides an overview of nanoscience, its application in orthodontics, the underlying processes of orthodontic pain, effective treatment options, and a summary of recent research in Nano-dentistry. The uses of this technology in healthcare span a wide range, including enhanced diagnostics, biosensors, and targeted drug delivery. The reason for this is that nanomaterials possess distinct qualities that depend on their size, which can greatly enhance human well-being and contribute to better health when effectively utilized. The field of dentistry has also experienced significant advancements, particularly in the past decade, especially in the utilization of nanomaterials and technology. Over time, there has been an increase in the availability of dental nanomaterials, and a diverse array of these materials have been extensively studied for both commercial and therapeutic purposes.

Study of Prevalence of Gastritis Caused by H. pylori and Correlation of Urease Test with Serology (ELISA) Test.

Introduction: H. pylori are a pathogen of global importance. Gram-negative curved flagellate bacilli are implicated as one of the most trivial complaints of and are associated with peptic ulcer disease gastritis ulcer and gastric malignancy. This study was performed to find out the prevalence of Helicobacter pylori (H. pylori) infection in patients presenting the symptoms related with gastritis with or without chemically known peptic ulcer. Materials and Methods: The study was undertaken with the help of the Christensen and quotes urease test on endoscopic biopsy specimen and correlated with the detection of immunoglobulin IgG in the serum against H. pylori by an ELISA technique. Results: A total of 67 cases were analyzed in which 29 (43%) cases were positive for H. pylori. The endoscopic findings of acid peptic diseases show 21 (31.4%) cases of stomach ulcer, and 3 (4.5%) have esophagitis, whereas 43 (64.1%) have nonulcer dyspepsia. There is strong positive association between the urease tesr and ELISA test. Conclusion: The urease test is a quick and inexpensive test with high specificity and sensitivity, but since it is an invasive test, it has reduced patient compliance.

Marine-derived polysaccharides and their therapeutic potential in wound healing application - A review.

Polysaccharides originating from marine sources have been studied as potential material for use in wound dressings because of their desirable characteristics of biocompatibility, biodegradability, and low toxicity. Marine-derived polysaccharides used as wound dressing, provide several benefits such as promoting wound healing by providing a moist environment that facilitates cell migration and proliferation. They can also act as a barrier against external contaminants and provide a protective layer to prevent further damage to the wound. Research studies have shown that marine-derived polysaccharides can be used to develop different types of wound dressings such as hydrogels, films, and fibres. These dressings can be personalised to meet specific requirements based on the type and severity of the wound. For instance, hydrogels can be used for deep wounds to provide a moist environment, while films can be used for superficial wounds to provide a protective barrier. Additionally, these polysaccharides can be modified to improve their properties, such as enhancing their mechanical strength or increasing their ability to release bioactive molecules that can promote wound healing. Overall, marine-derived polysaccharides show great promise for developing effective and safe wound dressings for various wound types.

A Comprehensive Review on Drug Therapies and Nanomaterials used in Orthodontic Treatment.

Orthodontic treatment typically requires an extended duration of 1-2 years to complete the treatment. Accelerating the rate of tooth movement during orthodontic treatment is essential for shortening the overall treatment duration. After the completion of orthodontic treatment, a prominent concern arises in the form of orthodontic relapse, where the teeth tend to revert to their original positions. This issue affects approximately 60% of the global population, underscoring the importance of implementing effective measures to address orthodontic relapse. An approach in this regard involves the targeted administration of herbal and synthetic drugs applied directly to the specific area of interest to facilitate tooth movement and prevent orthodontic relapse. Apart from this, researchers are investigating the feasibility of utilizing different types of nanoparticles to improve the process of orthodontic tooth movement. In recent years, there has been a noticeable increase in the number of studies examining the effects of various drugs on orthodontics. However, the currently available literature does not provide significant evidence relating to orthodontic tooth movement. In this review, the authors provide valuable information about the drugs and nanomaterials that are capable of further enhancing the rate of orthodontic tooth movement and reducing the risk of orthodontic relapse. However, a notable hurdle remains, i.e., there is no marketed formulation available that can enhance orthodontic tooth movement and reduce treatment time. Therefore, researchers should try herbal-synthetic approaches to achieve a synergistic effect that can enhance orthodontic tooth movement. In this nutshell, there is an urgent need to develop a non-invasive, patient-compliant, and cost-effective formulation that will provide quality treatment and ultimately reduce the treatment time. Another critical issue is orthodontic relapse, which can be addressed by employing drugs that slow down osteoclastogenesis, thereby preventing tooth movement after treatment. Nevertheless, extensive research is still required to overcome this challenge in the future.

Evaluation of Anti-plaque and Anti-gingivitis Efficacy of Two Commercially Available Herbal and Non-herbal Toothpastes.

BACKGROUND:  Plaque-associated oral disease affects a considerable portion of the population and is considered one of the major causes of tooth loss. The presence of plaque may be the reason for dental caries, gingivitis, periodontal problems, and halitosis. Many mechanical aids are used to control plaque, including toothbrushes, dental floss, mouth rinses, and dentifrices, and the most effective method of controlling gingivitis is supragingival plaque control. AIM AND OBJECTIVE: To evaluate and compare the anti-plaque and anti-gingivitis efficacy of commercially available herbal toothpaste (Meswak) and non-herbal toothpaste (Pepsodent). MATERIALS AND METHOD: 50 subjects aged between 10 and 15 years with a full complement of dentition were included in the study. The two toothpastes were provided to the subjects in plain white tubes by the investigator. Subjects were instructed to brush their teeth twice daily using the given toothpaste for 21 days. Plaque and gingival scores on days 0, 7, and 21 were recorded, and the data were subjected to statistical analysis. RESULT: At the end of the 21-day study, there was a statistically significant difference between the groups for plaque and gingival scores. CONCLUSION: The plaque and gingival scores were significantly reduced throughout the study in both groups. In comparison, the herbal dentifrices show more effectiveness in reducing plaque and gingival scores, but no statistically significant difference was seen between the two groups.

An Assessment of the Prevalence of Dental Caries, Oral Hygiene Status, Deft Index, and Oral Hygiene Habits Among Children With Special Healthcare Needs.

Background and objective Children with special healthcare needs are at an increased risk of oral health problems, including dental caries. Understanding the prevalence of dental caries, oral hygiene status, deft (decayed, extracted, filled teeth) index, and oral hygiene habits in this population is crucial for effective oral healthcare planning and interventions. The aim of this study was to assess the prevalence of dental caries, oral hygiene status, deft index, and oral hygiene habits among children aged 4-15 years with special healthcare needs in Jodhpur District, Rajasthan, India. Methods A cross-sectional study was conducted among 124 children from various, government and non-governmental organizations (NGO)-run special schools. Data on dental caries, oral hygiene status, deft index, and oral hygiene habits were collected using standardized tools and techniques. Descriptive statistics, including frequencies and percentages, were used to analyze the data. Results The prevalence of dental caries among children with special healthcare needs was 65%. The severity of dental caries varied, with 40% classified as mild, 20% as moderate, and 5% as severe. Additionally, 75% of the children exhibited poor oral hygiene, as indicated by the oral hygiene status assessment. The mean deft index score was 2.8, indicating an average dental caries experience among the participants. Regarding oral hygiene habits, 60% reported brushing their teeth once a day, while 40% reported brushing twice a day. However, a significant proportion (70%) reported non-fluoride use, and 55% stated they did not perform regular flossing. Conclusion This study highlights a high prevalence of dental caries, poor oral hygiene status, and suboptimal oral hygiene habits among children with special healthcare needs in Jodhpur District. The findings emphasize the need for targeted interventions focusing on preventive measures, oral health education, and improving access to oral healthcare for this vulnerable population. Further research with larger sample sizes and longitudinal study designs is warranted to validate these findings and develop effective strategies for enhancing oral health outcomes in children with special healthcare needs.

Drug Delivery Systems and Strategies to Overcome the Barriers of Brain.

The transport of drugs to the central nervous system is the most challenging task for conventional drug delivery systems. The reduced permeability of drugs through the blood-brain barrier is a major hurdle in delivering drugs to the brain. Hence, various strategies for improving drug delivery through the blood-brain barrier are being explored. Novel drug delivery systems (NDDS) offer several advantages, including high chemical and biological stability, suitability for both hydrophobic and hydrophilic drugs, and can be administered through different routes. Furthermore, the conjugation of suitable ligands with these carriers tends to potentiate targeting to the endothelium of the brain and could facilitate the internalization of drugs through endocytosis. Further, the intranasal route has also shown potential, as a promising alternate route, for the delivery of drugs to the brain. This can deliver the drugs directly to the brain through the olfactory pathway. In recent years, several advancements have been made to target and overcome the barriers of the brain. This article deals with a detailed overview of the diverse strategies and delivery systems to overcome the barriers of the brain for effective delivery of drugs.

Microbiome Medicine: Microbiota in Development and Management of Cardiovascular Diseases.

The gut microbiome consists of trillions of bacteria and other microbes whose metabolic activities and interactions with the immune system go beyond the gut itself. We are all aware that bacteria and other microorganisms have a significant impact on our health. Also, the health of the bacteria directly reflects the health status of the body where they reside. Eventually, alterations in the microbiome at different sites of a body are associated with many different diseases such as obesity, IBD, malnutrition, CVD, etc. Microbiota directly or indirectly affects the heart with the formation of plaques in the blood vessels, and cell walls become prone to lesion development. This ultimately leads to heightening the overall inflammatory status via increased bacterial translocation. Metabolites derived from the gut microbial metabolism of choline, phosphatidylcholine, and L-carnitine directly contribute to CVD pathology. These dietary nutrients have trimethylamine (TMA) moiety, which participates in the development of atherosclerotic heart disease. The objective of this review was to examine various metabolic pathways regulated by the gut microbiome that appear to alter heart function and lead to the development and progression of cardiovascular diseases, as well as how to target the gut microbiome for a healthier heart. In this review, we also discussed various clinical drugs having crosstalk between microbiota and heart and clinical trials for the gut-heart microbiome.

Design and in vitro performance evaluation of purified microparticles of pravastatin sodium for intestinal delivery.

The purpose of research was to develop a mucoadhesive multiparticulate sustained drug delivery system of pravastatin sodium, a highly water-soluble and poorly bioavailable drug, unstable at gastric pH. Mucoadhesive microparticles were formulated using eudragit S100 and ethyl cellulose as mucoadhesive polymers. End-step modification of w/o/o double emulsion solvent diffusion method was attempted to improve the purity of the product, that can affect the dose calculations of sustained release formulations and hence bioavailability. Microparticles formed were discrete, free flowing, and exhibited good mucoadhesive properties. DSC and DRS showed stable character of drug in microparticles and absence of drug polymer interaction. The drug to polymer ratio and surfactant concentration had significant effect on mean particle size, drug release, and entrapment efficiency. Microparticles made with drug: eudragit S100 ratio of 1:3 (F6) exhibited maximum entrapment efficiency of 72.7% and ex vivo mucoadhesion time of 4.15 h. In vitro permeation studies on goat intestinal mucosa demonstrated a flux rate (1,243 µg/cm(2)/h) that was 169 times higher than the flux of pure drug. The gastric instability problem was overcome by formulating the optimized microparticles as enteric-coated capsules that provided a sustained delivery of the highly water-soluble drug for 12 h beyond the gastric region. The release mechanism was identified as fickian diffusion (n = 0.4137) for the optimized formulation F6. Conclusively, a drug delivery system was successfully developed that showed delayed and sustained release up to 12 h and could be potentially useful to overcome poor bioavailability problems associated with pravastatin sodium.

Impact of COVID-19 on Dentistry.

Pandemic situations always impose devastating aftereffects on communities and cause chronic damaging effects on the healthcare system. Novel coronavirus disese-2019 (COVID-19) which has originated in China (Wuhan) is nowadays an emerging threat to public health across the world. It is spreading worldwide so rapidly and has started infecting people in all possible ways. Several dental care facilities in affected countries are completely closed or have been only providing minimal treatment for emergency cases since the whole lockdown has been announced. However, in some affected countries, they are still providing regular dental treatment. This discrepancy could be because of the dearth of proper awareness, knowledge, protocol, or guidelines. HOW TO CITE THIS ARTICLE: Kshirsagar MM, Dodamani AS, Deokar RN, et al. Impact of COVID-19 on Dentistry. Int J Clin Pediatr Dent 2021;14(5):711-714.

Teledentistry: A New Horizon in COVID-19 Pandemic for Oral Health.

Currently, all of us are experiencing emotions, thoughts, and situations we have never experienced before. It is not that there were no pandemics earlier. In light of the COVID-19 pandemic, health issues are growing. It has shaken the entire world and created global panic. In a way, it is affecting oral health also. Taking care of oral health is as important as looking after physical health. There is a need for a range of treatments to anticipate oral health issues. Strategies to combat these oral health issues should use options like teledentistry to develop effective methods of support. How to cite this article: Kshirsagar MM, Dodamani AS, Dodamani GA, et al. Teledentistry: A New Horizon in COVID-19 Pandemic for Oral Health. Int J Clin Pediatr Dent 2021;14(3):441-442.

Comparison of Different Dentin Deproteinizing Agents on the Shear Bond Strength of Resin-bonded Dentin.

AIM: To assess and analyze the resin-bonded dentin in terms of shear bond strength after using deproteinizing agents 5% sodium hypochlorite, 10% sodium hypochlorite, and bromelain. MATERIALS AND METHODS: Overall 140 permanent and intact human premolars were split into four groups, three experimental groups and one control group. In all four groups, the occlusal surface of the teeth was wet ground to expose superficial dentin. In group I, teeth were etched and deproteinized with 5% sodium hypochlorite. In group II, teeth were etched and deproteinized with 10% sodium hypochlorite. In group III, teeth were etched and bromelain was used to deproteinize. In group IV, teeth were etched and no deproteinization was being performed and simultaneous fulfillment of the resin composite and later inserted into the plastic tube and polymerized with light. Samples were stored at 37°C for 24 hours and the later samples were transferred to the universal testing machines to shear bond strength analysis at a speed of 0.5 mm/minute. RESULTS: The outcome of the bond strength was significantly influenced by the application of bromelain enzymes. A remarkable difference was observed between the shear bond strength of sodium hypochlorite (5 and 10%) and in the bromelain enzyme-treated group. Group III showed better results than group I and group II. CONCLUSION: This study concluded that bromelain shear has the maximum value for shear bond strength. Bond strength improved because of removal of unsupported collagen fiber with bromelain enzyme after acid etching. CLINICAL SIGNIFICANCE: Natural pineapple enzyme, i.e., bromelain improves bond strength by removal of unsupported collagen fiber. Hence, it is completely safe to use. HOW TO CITE THIS ARTICLE: Khan R, Sharma N, Garg Y, et al. Comparison of Different Dentin Deproteinizing Agents on the Shear Bond Strength of Resin-bonded Dentin. Int J Clin Pediatr Dent 2020;13(S-1):S69-S77.

Oral health status and treatment needs of substance abusers in Western Uttar Pradesh.

BACKGROUND: Substance abuse has often associated with high caries, poor periodontal health, and altered functioning of the individual. The substance abuse may be natural or synthetic in origin, both causing deleterious effect on the oral and overall health of the individual. AIM: To assess the oral health status and treatment needs of substance abusers attending deaddiction centers in Western Uttar Pradesh. MATERIALS AND METHODS: A cross-sectional study was conducted among 220 substance abusers from 6 randomly selected deaddiction centers. The subjects were divided into four groups: Group 1, alcohol (A); Group 2, nicotine (N); Group 3, alcohol + nicotine (AN); and Group 4, other drugs (O). A demographic record along with full-mouth examination was recorded based on the World Health Organization pro forma. RESULTS: The overall results showed that out of the total participants, 144 had oral mucosal lesions. Alcohol group had significantly higher mean community periodontal index code 3 (pockets 4-5 mm) than the other groups (P < 0.05). The prevalence of decayed, missing, filled teeth (DMFT) was 83.33%, and the mean DMFT of the alcohol group was significantly higher than the other combinations group (P < 0.01). CONCLUSIONS: The oral health status of substance abusers was poor, with a large number of oral mucosal lesions. The dental caries status and periodontal status were the worst among the alcohol group.

Multifaceted assessment of dentine hypersensitivity, evaluation of demographic prevalence along with associated factors: A cross-sectional study.

BACKGROUND: Dentine hypersensitivity (DH) is a relatively common problem which may affect the adult population. The etiology remains multi-factorial with interactions between stimulus and pre-disposing factors causing its aggravation. AIM: To study the prevalence of DH and associated factors and also to find the association between various factors and DH. MATERIALS AND METHODS: A cross-sectional study was carried out and a total of 5091 patients, both male and females, were evaluated through questionnaire. Out of the total only 1400 patients were included in the study and were further evaluated clinically. A complete demographic data was obtained and the DH was confirmed by the use of air -water jet of the dental chair and scratching the suspected tooth with a dental probe. The pain response of the subject was recorded using the visual analog scale (VAS) and verbal rating scale (VRS). The data obtained was statistically evaluated and Chi-square test was applied for comparison of different demographic factors with DH. RESULTS: The overall prevalence of DH was 27.4%. Various demographic factors were found to affect DH such as age, gender, education, and diet. The most common stimulus was found to be cold (21.4%) and common predisposing factor was gingival recession and attrition (28.6%). Clinical examination yielded a statistically significant association between VAS and VRS scores for DH and demographic factors. CONCLUSION: The prevalence of DH in present study was 27.4% which is attributed to gingival recession as predisposing factor and cold stimuli as the precipitating factor.

Effects of different deproteinizing agents on topographic features of enamel and shear bond strength - An in vitro study.

OBJECTIVES: To evaluate and compare the effect of different enamel deproteinizing agents on topographic features of enamel and shear bond strength before acid etching. MATERIALS AND METHOD: In total, 120 sound human maxillary premolars were taken and divided into three groups: Group 1 control (37% phosphoric acid (H3PO4), Group 2, (5.25% Sodium Hypochlorite (NaOCl)+ 37% H3PO4, and Group 3, (10% Papain gel + 37% H3PO4). These groups were further divided into A and B subgroups. In subgroups 1A, 2A, and 3A (n30) topographic features were evaluated using Scanning electron microscope (SEM) at different magnifications. Insub-groups 1B, 2B, and 3B (n90) metal brackets were bonded with Transbond™ XT, and all the samples were subjected for Shear Bond Strength (SBS) evaluation using universal testing machineat a cross speed of 0.5 mm2/min. The failure mode was analyzed using adhesive remnant index (ARI). Statistical analysis was done using one-way ANOVA for the shear bond strength, and Kruskal-Wallis test followed by Mann-Whitneywas performed for ARI scores. RESULTS: SEM showed predominance of type 3 etching pattern in control Group (1A) and type 1 and type 2 in deproteinizedGroups (2A and 3A). Mean values of shear bond strength showed statistically significant differences between evaluated groups (P < 0.005). The lowest and highest shear bond strength was attributed to Group 1B (Control) and 3B (10% papain gel), respectively. Statisticallysignificant differences were noted for the mean ARI scores between control and deproteinized group (P < 0.05). CONCLUSION: 10% papain geland 5.25% NaOCl can be used as deproteinizing agents on enamel surface before acid etchingto enhance the shear bond strength of orthodontic brackets.