Effect of Surface Topography on the Primary Stability of Miniscrew Implants in Orthodontics-A Systematic Review and Meta-Analysis.

This present study has the purpose of determining how surface topography of implants affects the initial stability of miniscrew implants (MSIs). Electronic databases like PubMed Central, Scopus, Web of Science, Embase, and Cochrane Library, as well as reference lists, were thoroughly searched up until September 2022. Clinical trials involving individuals who got anchorage through mini-implants, along with information on categories of mini-implants dimension, shape, thread design, and insertion site, were required as part of the eligibility criteria. Primary and secondary stability were also assessed. We carried out selection process for the study, extraction of data, quality assessment, and a meta-analysis. The qualitative synthesis included 10 papers: three randomized, four prospective, and four retrospective clinical investigations. The results of this meta-analysis demonstrate that the clinical state of MIs is controlled by their geometrical surface qualities, which are also influenced by their shape and thread design. According to the evidence this meta-analysis produced, this circumstance exists. The duration of the follow-up period and MI success rates did not correlate with one another.

Proficiency of Clear Aligner Therapy: A Systematic Review and Meta-Analysis.

The aim of this study was to evaluate the efficacy and efficiency of orthodontic treatment using clear aligner therapy (CAT). This efficiency was measured using the Peer Assessment Rating (PAR) index, the American Board of Orthodontics (ABO) index, or the similarity between the final ClinCheck and the final scanned models. A search was done electronically between 1998 and 2021 using the Cochrane Library, PubMed, and Google Scholar databases. Three reviewers individually rated the articles. The ROBINS tool and the Cochrane risk of bias tool were used to evaluate the quality of observational research and randomized controlled trials, respectively. The degree of certainty for each selected outcome was evaluated using the grading of recommendations assessment, development, and evaluation (GRADE) approach. Six studies with a total of 166 participants were considered after the full texts of 61 potential reports were reviewed. This research included in the review covered the period from 1998 to 2021 in retrospect. According to the current systematic review and meta-analysis, transparent aligners had a successful outcome. In mild to moderate cases, aligner treatment appears to have a significant advantage in terms of efficiency (treatment time); nonetheless, insufficient evidence of efficacy was observed based on multiple cross-sectional investigations. When compared to traditional brackets, clear aligners provided a more stable course of treatment.

To Analyze the Mesiobuccal Root Canal of Maxillary First Molar using Cone Beam Computed Tomography: An Ex-vivo Study.

Aim and Objectives: The purpose of this study was to use cone bar CT to investigate the root trench morphology of two-hundred mesiobuccal permanent first molars in the maxilla. Materials and Methods: The distobuccal and palatal roots were removed at the furcation in 250 maxillary first molars. The mesiobuccal roots were then imaged using cone beam computed tomography on all specimens. The specimens were analyzed and compared to one another." This study looked into the following factors. How Many Canals There Are and What Shape Those Canals Take Errors such as lateral canals, apical delta, calcified segments, and others. Result: Vertucci's trench configuration, kinds I, II, III, IV, V, and VII, were seen in 30%, 20%, 5%, 6%, 7%, and 2.5% of the teeth, respectively. Calcified sections were found in the coronal third of the MB1 trench for eight of the samples, and in the central third for two of the samples. The MB1 trench did not have any calcifications at its very end. The coronal 33 percent of the MB2 trench was calcified in eight samples, but no calcifications were seen in the middle or upper thirds. Conclusion: Noninvasively and with little radiation, a cone beam CT scan can help you learn about your root canal setup.

Effect of Dental Varnishes in Prevention of Enamel Demineralization Adjacent to Orthodontic Brackets.

Aim: The aim of the current research was to assess the ability of different dental varnishes in averting enamel demineralization adjoining the orthodontic brackets. Materials and Methods: Seventy-five premolars devoid of dental caries that were subjected to extraction for orthodontic purposes were employed in this research. The surface of enamel was etched with 37% phosphoric acid and subjected to primer application. Individual brackets were placed on the midregion of the buccal surfaces of the premolars with Transbond™ XT adhesive. Postbracket bonding, the dry premolar tooth samples were set aside cautiously. The samples were then allocated to three groups: Group I: Duraphat Varnish, Group II: Clinpro XT Varnish, and Group III: Profluorid Varnish. Every sample was independently subjected to immersion in demineralizing solution for a period of 96 h at 37°C in an incubator. Areas of demineralization were evaluated by documenting the microhardness along the severed surface using a microhardness tester equipped with a Vickers diamond. Results: The highest surface microhardness was noted with Profluorid Varnish group at 328.48 ± 1.12 in pursuit by Clinpro XT Varnish group at 322.08 ± 0.04 as well as Duraphat Varnish group at 307.42 ± 0.28 with a statistically noteworthy dissimilarity amid the groups. Conclusion: In conclusion, the three varnishes employed had an influence on the prevention of enamel demineralization surrounding the orthodontic brackets. Profluorid varnish however exhibited maximum efficiency in avoiding enamel demineralization versus Clinpro XT varnish as well as Duraphat varnish group.

Ponticulus Posticus: An Important Diagnostic Finding Often Missed in Lateral Cephalograms.

AIM: The purpose of the current study was to investigate the presence of the ponticulus posticus (PP) frequently encountered in lateral cephalograms. MATERIALS AND METHODS: About 500 patients of age 12-40 years were selected whose digital lateral cephalogram was recorded and traced to confirm the presence of the PP and categorize as: (A) Absent, as evidenced by lateral cephalograms. (B) Complete PP evidenced by the presence of circumferential bone bridge that connected the upper articular process to the atlas's posterior arch. (C) Partial PP: presented as a bone spike that protruded from the top articular process or the posterior arch of the atlas and extended above the vertebral artery sulcus. Symptoms of migraine, shoulder discomfort, orofacial pain, and headache were also evaluated on interaction with the patients. Using the Chi-square test, the relationship between the patient's gender and the presence of the PP was assessed. A p-value of 0.05 or less was regarded as statistically significant. RESULTS: About 10% of the patients reported with the presence of complete variant, 70% with partial variant and rest 20% of patients with neither a partial nor a complete form of PP. There was no statistically significant association between the PP and gender, as indicated by the Chi-square values (3.146; p = 0.526). CONCLUSION: On conclusion, according to the findings of the current study, patients with a complete form of PP experience more symptoms than those with a partial form of PP. In both groups, the PP frequency was higher in females. CLINICAL SIGNIFICANCE: In lateral cephalograms, the cervical spine region is typically ignored and given little weight. A common variation of atlas vertebrae is the PP, which is located in the posterior arch of the atlas. The PP exacerbates symptoms, such as migraine, tension headaches, shoulder pain, double vision, vertigo, stroke, and pain in the neck and orofacial region. Therefore, orthodontic specialists serve as initial diagnosticians and direct the patients to qualified physicians so that they can experience symptom relief.

Artificial Intelligence and Machine Learning for Automated Cephalometric Landmark Identification: A Meta-Analysis Previewed by a Systematic Review.

Digital dentistry has become an integral part of our practice today, with artificial intelligence (AI) playing the predominant role. The present systematic review was intended to detect the accuracy of landmarks identified cephalometrically using machine learning and artificial intelligence and compare the same with the manual tracing (MT) group. According to the PRISMA-DTA guidelines, a scoping evaluation of the articles was performed. Electronic databases like Doaj, PubMed, Scopus, Google Scholar, and Embase from January 2001 to November 2022 were searched. Inclusion and exclusion criteria were applied, and 13 articles were studied in detail. Six full-text articles were further excluded (three articles did not provide a comparison between manual tracing and AI for cephalometric landmark detection, and three full-text articles were systematic reviews and meta-analyses). Finally, seven articles were found appropriate to be included in this review. The outcome of this systematic review has led to the conclusion that AI, when employed for cephalometric landmark detection, has shown extremely positive and promising results as compared to manual tracing.

Comparison of Frequency of Congenitally Missing Upper Lateral Incisors among Skeletal Class I, II and III Malocclusions.

AIM: The present investigation aims to find out the frequency of congenitally missing upper lateral incisors among skeletal class I, II, and III malocclusions and to find out its variability among different genders. MATERIALS AND METHODS: The study sample included orthopantomograms (OPGs) and a lateral cephalogram of 1,000 patients retrieved from previous records. Of the selected samples, 290 were males and 710 were females. Orthopantomograms helped diagnose the presence of unilateral/bilateral maxillary lateral incisors. Results and statistics: Of the 1,000 samples, 710 (71%) were female and 290 (29%) were male patients. An estimated 37 (3.77%) patients were found to have missing maxillary lateral incisors. Of the female patients, 4.04% were having missing laterals, whereas 3.10% of the male patients were having agenesis of maxillary incisors. Totally, 0.9% of missing upper laterals were recorded in males, whereas 2.8% of missing lateral incisors in upper arch were found in females. A total of 54.16% of skeletal class I, 33.33% of skeletal class II, and 12.5% of skeletal class III cases were found to have missing upper lateral incisors. CONCLUSION: The prevalence rate for congenitally missing upper lateral incisors in orthodontic adolescent Odia population in Bhubaneswar is 3.77%. The females had a greater percentage of agenesis of the upper lateral incisor when compared to males. An estimated 54.16% of skeletal class I, 33.33% of skeletal class II, and 12.5% of skeletal class III cases were found to have missing upper lateral incisors. This difference might be due to genetic variations or different environmental conditions. A multidisciplinary treatment protocol must be planned to manage the missing maxillary lateral incisor and to restore the impaired esthetics and function.

Comparison of the Perception of Pain during Fixed Orthodontic Treatment with Metal and Ceramic Brackets.

INTRODUCTION: Pain is experienced by patients during various fixed orthodontic procedures such as placement of separators, insertion of arch wire and its activations, orthopedic appliances such as headgear, and debonding of the appliance. This study was formulated with the background that the level of pain sensation differs between conventional metal and ceramic brackets, arch wire being the same. MATERIALS AND METHODS: The sample comprised 40 patients. The patients were separated into two groups: Group A (metal brackets) and Group B (ceramic brackets). In Group A, the brackets were bonded with 0.022" conventional stainless steel brackets (Unitek Gemini, 3M, Monrovia, California). In Group B, the brackets were bonded with ceramic brackets (Unitek Gemini Clear Brackets, 3M, Monrovia, California). The bonding of the brackets was carried out according to the conventional etching, priming, and curing technique. A 0.016" NiTi (nickel titanium) arch wire was used as the first arch wire. The intensity of pain was documented in a figure containing two 100-mm visual analog scales (VASs). RESULTS: The level of pain reduced in intensity in due course. During 1 month, VAS scores increased at the end of day 1 (24 h) for the metal and ceramic group. The pain then decreased for up to 5 days. The average pain intensity reached 4.44 in the ceramic group, whereas it was 2.7 in the metal group for the upper anterior region. It decreased up to 1 in the ceramic and 0.22 in the metal group. CONCLUSION: Patients bonded with ceramic brackets experienced a higher and more severe pain of longer duration than individuals treated with conventional brackets.

A Cone-beam Computed Tomography Interpretation of Malar Bone Changes in Skeletal Malocclusion.

AIM: The purpose of this cross-sectional study is to signify malar bone anatomy and to obtain linear correlation with varied skeletal pattern by utilizing cone beam computed tomographic views. MATERIALS AND METHODS: The experimental sample consisted of cone-beam computed tomography (CBCT) scans of 30 patients taken for the purpose of orthodontic treatment and peri implant planning (16 males and 14 females), 11-30 years of age (mean, 23.4 years). The sex and age were documented for all samples and nine landmarks were evaluated. The various CBCT were categorized into different malocclusions based on wits appraisal. Its prevalence was collated with age, sex and various malocclusion by Chi-square test. RESULTS: Age and gender altogether influenced M1. The mean posterior zygomatic bone width (M1) for all sample was 63.7 mm. For M1 estimations, no huge contrast was observed among left and right side (p = 0.915). The mean anteriorzygomatic bone width (M2) was 51.8 mm. No noteworthy contrast amongst two sides (p = 0.995) or age (p = 0.067) was seen. Although sex altogether influenced M3 variety (p = 0.003), the mean greatest cortical thickness (max CT) (M4) was 9.36 mm, significant difference was observed between the minimum cortical thickness of skeletal class I and skeletal class III malocclusion design. CONCLUSION: Detailed evaluation of malar bone should be performed prior to any ortho-surgical procedure using CBCT. CLINICAL SIGNIFICANCE: Our study signifies the importance of consideration of zygoma during any pre-treatment evaluation of skeletal malocclusion. It also marks the pivotal role of zygoma while considering gross facial esthetics. Precise assurance of zygomatic bone size may likewise aid the choice of fitting surgeries and determination of zygomatic implant area. How to cite this article: Dash BP, Reddy R, Mohanty P, et al. A Cone-beam Computed Tomography Interpretation of Malar Bone Changes in Skeletal Malocclusion. J Contemp Dent Pract 2019;20(11):1319-1322.

A Comparative Study of Dermatoglyphics in Subjects with Hypodivergent and Hyperdivergent Growth Patterns.

AIMS AND OBJECTIVES: Dermatoglyphics is the study of fingerprints. Fingerprints are unique for an individual person. This aim of this study was to note if any correlation exists between dermatoglyphics and growth patterns. MATERIALS AND METHODS: Lateral cephalograms of 100 patients were recorded and traced. Mandibular plane angle was measured according to Steiner's analysis to determine the type of growth pattern and thus separated into two groups (50 in each group): Group I being horizontal growth pattern (HGP) and Group II being vertical growth pattern (VGP). All statistical analysis was performed with SPSS version 21. RESULTS: The ulnar loops in Group II were highest in frequency, and central pocket loops were lowest in frequency in both groups. CONCLUSION: Ulnar loops were increased in VGP whereas whorls were increased in HGP. There was absence of central pocket loops in VGP.

A Comparative Evaluation of Mixed Dentition Analysis on Reliability of Cone Beam Computed Tomography Image Compared to Plaster Model.

AIMS AND OBJECTIVE: The aim of the study was to evaluate the reliability of cone beam computed tomography (CBCT) obtained image over plaster model for the assessment of mixed dentition analysis. MATERIALS AND METHODS: Thirty CBCT-derived images and thirty plaster models were derived from the dental archives, and Moyer's and Tanaka-Johnston analyses were performed. The data obtained were interpreted and analyzed statistically using SPSS 10.0/PC (SPSS Inc., Chicago, IL, USA). Descriptive and analytical analysis along with Student's t-test was performed to qualitatively evaluate the data and P < 0.05 was considered statistically significant. RESULTS: Statistically, significant results were obtained on data comparison between CBCT-derived images and plaster model; the mean for Moyer's analysis in the left and right lower arch for CBCT and plaster model was 21.2 mm, 21.1 mm and 22.5 mm, 22.5 mm, respectively. CONCLUSION: CBCT-derived images were less reliable as compared to data obtained directly from plaster model for mixed dentition analysis.

Gingival Zenith Positions and Levels of Maxillary Anterior Dentition in Cases of Bimaxillary Protrusion: A Morphometric Analysis.

AIM: To investigate the two clinical parameters, such as gingival zenith positions (GZPs) and gingival zenith levels (GZLs), of maxillary anterior dentition in bimaxillary protrusion cases and collate it with severiety of crown inclination. MATERIALS AND METHODS: Gingival zenith position and GZL in 40 healthy patients (29 females and 11 males) with an average age of 21.5 years were assessed. Inclusion criteria involved absence of periodontal diseases, Angle's class I molar relationship, and upper anterior proclination within 25 to 45° based on Steiner's analysis; exclusion criteria included spacing, crowding, anterior restoration and teeth with incisor attrition or rotation. The GZP was evaluated using digital calipers from voxel-based morphometry (VBM), and GZL was assessed from the tangent drawn from GZP of central incisor and canines to the linear vertical distance of GZP of lateral incisor. RESULTS: All the central incisors showed a GZP distal to VBM with a mean average of 1 mm. Severe proclination between 40 and 45° showed a statistically significant variation. Lateral incisors displayed a mean of 0.5 mm deviation of GZP from the vertically bisected midline. In 80% of canine population, GZP was centralized. CONCLUSION: We conclude that the degree of proclination of maxillary anterior dentition was correlated to the gingival contour in bimaxillary cases. The investigation revealed that there is a variation in the location of GZP as the severity of proclination increases. CLINICAL SIGNIFICANCE: This study highlights the importance of microesthetics in fixed orthodontic treatment. The gingival contour should be unaltered while retraction during management of bimaxillary protrusion.

Reforming craniofacial orthodontics via stem cells.

Stem cells are the most interesting cells in cell biology. They have the potential to evolve as one of the most powerful technologies in the future. The future refers to an age where it will be used extensively in various fields of medical and dental sciences. Researchers have discovered a number of sources from which stem cells can be derived. Craniofacial problems are very common and occur at all ages. Stem cells can be used therapeutically in almost every field of health science. In fact, many procedures will be reformed after stem cells come into play. This article is an insight into the review of the current researches being carried out on stem cells and its use in the field of orthodontics, which is a specialized branch of dentistry. Although the future is uncertain, there is a great possibility that stem cells will be used extensively in almost all major procedures of orthodontics.

In-vivo evaluation of salivary nickel and chromium levels in conventional and self-ligating brackets.

INTRODUCTION: Our objective was to evaluate and compare the salivary levels of nickel and chromium before and 1, 7, and 30 days after placement of conventional and self-ligating appliance systems. METHODS: Twenty women were randomly divided into 2 groups. Patients in group 1 had conventional brackets bonded to their teeth; in group 2, self-ligating brackets were bonded. Four samples of unstimulated saliva were collected from each patient 1 hour before placement of the fixed appliance, and 1, 7, and 30 days after placement of the appliance. The chemical analyses for nickel and chromium levels were performed with an atomic absorption spectrometer (PerkinElmer, Shelton, Conn). Two-way repeated measures analysis of variance by ranks (Friedman test) were used to test the statistical significance of differences in the concentrations of nickel and chromium before and after placement of the appliances. Post-hoc pair-wise comparisons among groups of the same element were calculated by using the Wilcoxon signed rank test. A value of P ≤0.05 was considered significant. RESULTS: Nickel and chromium released into saliva from conventional and self-ligating brackets progressively increased from days 1 to 7 and then decreased at day 30. Nickel release was less, and chromium release was greater in the conventional bracket group. CONCLUSIONS: Both the conventional and the self-ligating brackets did not seem to affect significantly the nickel and chromium concentrations in saliva during the first month of treatment.

A family of intermediate filament-like proteins is sequentially assembled into the cytoskeleton of Toxoplasma gondii.

The intracellular protozoan parasite Toxoplasma gondii divides by a unique process of internal budding that involves the assembly of two daughter cells within the mother. The cytoskeleton of Toxoplasma, which is composed of microtubules associated with an inner membrane complex (IMC), has an important role in this process. The IMC, which is directly under the plasma membrane, contains a set of flattened membranous sacs lined on the cytoplasmic side by a network of filamentous proteins. This network contains a family of intermediate filament-like proteins or IMC proteins. In order to elucidate the division process, we have characterized a 14-member subfamily of Toxoplasma IMC proteins that share a repeat motif found in proteins associated with the cortical alveoli in all alveolates. By creating fluorescent protein fusion reporters for the family members we determined the spatiotemporal patterns of all 14 IMC proteins through tachyzoite development. This revealed several distinct distribution patterns and some provide the basis for novel structural models such as the assembly of certain family members into the basal complex. Furthermore we identified IMC15 as an early marker of budding and, lastly, the dynamic patterns observed throughout cytokinesis provide a timeline for daughter parasite development and division.

A Toxoplasma MORN1 null mutant undergoes repeated divisions but is defective in basal assembly, apicoplast division and cytokinesis.

The membrane occupation and recognition nexus protein 1 (MORN1) is highly conserved among apicomplexan parasites and is associated with several structures that have a role in cell division. Here we dissected the role of MORN1 using the relatively simple budding process of Toxoplasma gondii as a model. Ablation of MORN1 in a conditional null mutant resulted in pronounced defects suggesting a central role for MORN1 in apicoplast segregation and in daughter cell budding. Lack of MORN1 resulted in double-headed parasites. These Janus-headed parasites form two complete apical complexes but fail to assemble a basal complex. Moreover, these parasites were capable of undergoing several more budding rounds resulting in the formation of up to 16-headed parasites conjoined at the basal end. Despite this segregation defect, the mother's cytoskeleton was completely disassembled in every budding round. Overall this argues that successful completion of the budding is not required for cell cycle progression. None of the known basal complex components, including a set of recently identified inner membrane complex (IMC) proteins, localized correctly in these multi-headed parasites. These data suggest that MORN1 is essential for assembly of the basal complex, and that lack of the basal complex abolishes the contractile capacity assigned to the basal complex late in daughter formation. Consistent with this hypothesis we observe that MORN1 mutants fail to efficiently constrict and divide the apicoplast. We used the null background provided by the mutant to dissect the function of subdomains of the MORN1 protein. This demonstrated that deletion of a single MORN domain already prevented the function of MORN1 whereas a critical role for the short linker between MORN domains 6 and 7 was identified. In conclusion, MORN1 is required for basal complex assembly and loss of MORN1 results in defects in apicoplast division and daughter segregation.

Parasite stage-specific recognition of endogenous Toxoplasma gondii-derived CD8+ T cell epitopes.

BACKGROUND: BALB/c mice control infection with the obligate intracellular parasite Toxoplasma gondii and develop a latent chronic infection in the brain, as do immunocompetent humans. Interferon-gamma-producing CD8+ T cells provide essential protection against T. gondii infection, but the epitopes recognized have so far remained elusive. METHODS: We employed caged major histocompatibility complex molecules to generate approximately 250 H-2L(d) tetramers and to distinguish T. gondii-specific CD8+ T cells in BALB/c mice. RESULTS: We identified 2 T. gondii-specific H-2L(d)-restricted T cell epitopes, one from dense granule protein GRA4 and the other from rhoptry protein ROP7. H-2L(d)/GRA4 reactive T cells from multiple organ sources predominated 2 weeks after infection, while the reactivity of the H-2L(d)/ROP7 T cells peaked 6-8 weeks after infection. BALB/c animals infected with T. gondii mutants defective in establishing a chronic infection showed altered levels of antigen-specific T cells, depending on the T. gondii mutant used. CONCLUSIONS: Our results shed light on the identity and the parasite stage-specificity of 2 CD8+ T cell epitopes recognized in the acute and chronic phase of infection with T. gondii.

MORN1 has a conserved role in asexual and sexual development across the apicomplexa.

The gene encoding the membrane occupation and recognition nexus protein MORN1 is conserved across the Apicomplexa. In Toxoplasma gondii, MORN1 is associated with the spindle poles, the anterior and posterior rings of the inner membrane complex (IMC). The present study examines the localization of MORN1 during the coccidian development of T. gondii and three Eimeria species (in the definitive host) and erythrocytic schizogony of Plasmodium falciparum. During asexual proliferation, MORN1 is associated with the posterior ring of the IMCs of the multiple daughters forming during T. gondii endopolygeny and schizogony in Eimeria and P. falciparum. Furthermore, the expression of P. falciparum MORN1 protein peaked in late schizogony. These data fit a model with a conserved role for MORN1 during IMC assembly in all variations of asexual development. An important new observation is the reactivity of MORN1 antibody with certain sexual stages in T. gondii and Eimeria species. Here MORN1 is organized as a ring-like structure where the microgametes bud from the microgametocyte while in mature microgametes it is present near the flagellar basal bodies and mitochondrion. These observations suggest a conserved role for MORN1 in both asexual and sexual development across the Apicomplexa.

Unusual kinetic and structural properties control rapid assembly and turnover of actin in the parasite Toxoplasma gondii.

Toxoplasma is a protozoan parasite in the phylum Apicomplexa, which contains a number of medically important parasites that rely on a highly unusual form of motility termed gliding to actively penetrate their host cells. Parasite actin filaments regulate gliding motility, yet paradoxically filamentous actin is rarely detected in these parasites. To investigate the kinetics of this unusual parasite actin, we expressed TgACT1 in baculovirus and purified it to homogeneity. Biochemical analysis showed that Toxoplasma actin (TgACT1) rapidly polymerized into filaments at a critical concentration that was 3-4-fold lower than conventional actins, yet it failed to copolymerize with mammalian actin. Electron microscopic analysis revealed that TgACT1 filaments were 10 times shorter and less stable than rabbit actin. Phylogenetic comparison of actins revealed a limited number of apicomplexan-specific residues that likely govern the unusual behavior of parasite actin. Molecular modeling identified several key alterations that affect interactions between monomers and that are predicted to destabilize filaments. Our findings suggest that conserved molecular differences in parasite actin favor rapid cycles of assembly and disassembly that govern the unusual form of gliding motility utilized by apicomplexans.

Calcium binding protein 1 of the protozoan parasite Entamoeba histolytica interacts with actin and is involved in cytoskeleton dynamics.

Blocking expression of EhCaBP1, a calmodulin-like, four EF-hand protein from the protozoan parasite Entamoeba histolytica, resulted in inhibition of cellular proliferation. In this paper we report that EhCaBP1 is involved in dynamic changes of the actin cytoskeleton. Both endocytosis and phagocytosis were severely impaired in cells where EhCaBP1 expression was blocked by inducible expression of the antisense RNA. In wild-type cells both actin and EhCaBP1 were found to co-localize in phagocytic cups and in pseudopods. However, in antisense-blocked cells the phagocytic cup formation is affected. Analysis of the staining patterns in the presence and absence of actin dynamics inhibitors, jasplakinolide and cytochalasin D suggested that EhCaBP1 and polymerized F-actin co-localize on membrane protrusions. Direct interaction between soluble EhCaBP1 and F-actin was further demonstrated by a co-sedimentation assay. A variant of EhCaBP1 did not bind F-actin showing the specificity of the interaction between EhCaBP1 and actin. There is no significant change in the kinetics of in vitro polymerization of actin in presence of EhCaBP1, indicating that EhCaBP1 does not affect filament treadmilling. In addition, using atomic force microscopy; it was found that filaments of F-actin, polymerized in presence of EhCaBP1, were thinner. These results indicate that EhCaBP1 may be involved in dynamic membrane restructuring at the time of cell pseudopod formation, phagocytosis and endocytosis in a process mediated by direct binding of EhCaBP1 to actin, affecting the bundling of actin filaments.