Browsing by Author "Rodrigues, Danieli C."
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Item A Comprehensive in Vitro and in Vivo Failure Analysis of Titanium Dental Implant Systems(2018-08) Sridhar, Sathyanarayanan; Rodrigues, Danieli C.This dissertation provides a novel approach to understand failure modes and evaluate the surface performance of commercially pure (cp) titanium (Ti) dental implants (DI). It is based on the hypothesis that multiple oral factors can damage the titanium oxide (TiO2) layer leading to peri-implant dissolution of metal ions. This study is comprised of three aims to understand the effect of (i) surgical insertion in different bone qualities; (ii) bacteria colonization; (iii) occlusal forces on the surface of DI. In the aim 1, DI were inserted following surgical procedure in simulated bone materials of different densities to check the possibility of surface exfoliation and corrosion behavior. Powder x-ray diffraction (XRD) of ground specimen from the insertion site was performed to detect particle release. ASTM standard electrochemical corrosion tests were performed to evaluate the corrosion behavior of DI post-insertion. In the aim 2, surface analyses of in vivo failed retrievals were performed. DI were immersed in in vitro polyculture of early colonizers (Stretptococcus mutans, S. salivarius, S. sanguinis), and late colonizers (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis) for 30 days. In the aim 3, cyclic occlusal forces were employed on DI immersed in (i) phosphate buffered saline (PBS) and in (ii) bacterial polyculture. Optical microscope, x-ray photoelectron spectroscopy (XPS), and electrochemical corrosion tests were performed to evaluate the surface-morphology, chemistry, and potential of (i) failed explanted retrievals, and (ii) DI obtained post-in vitro tests. Powder XRD results post-insertion test confirmed that particles were not released due to the insertion procedure irrespective of bone density. Electrochemical corrosion results post-insertion further corroborated that the surface integrity was not compromised due to insertion irrespective of bone quality. In vivo retrieval analyses suggested that both early- and late-colonizers degraded the surface- morphology (discoloration, pitting, scratches, and fractures) and chemistry (thinning/depletion of TiO2 layer with respect to the control). However, in vitro bacteria immersion tests showed that late- colonizers inflicted more damage to the surface chemistry compared to the early colonizers. Electrochemical corrosion results also indicated higher corrosion rate (not statistically significant) for DI immersed in late colonizers compared to early colonizers and their respective controls. The surface degradation due to bacteria adhesion was aggravated in the presence of mechanical forces. XPS analysis illustrated depleted TiO2 layer for DI exposed to cyclic loading in circulating broth containing bacteria compared to DI subjected to fatigue test in PBS. The overall findings of this study indicated that bacteria could degrade the surface which would be exacerbated by mechanical loading. This dissertation highlights the need to focus on the material surface, as particle release into the peri-implant tissue might trigger osteolysis and affect biological integration.Item Can Oral Bacteria and Mechanical Fatigue Degrade Zirconia Dental Implants in Vitro?(American Chemical Society, 2019-05-15) Siddiqui, Danyal A.; Sridhar, Sathyanarayanan; Wang, Frederick; Jacob, Joel J.; Rodrigues, Danieli C.; 0000-0002-2398-5979 (Siddiqui, DA); 0000-0002-0389-0833 (Rodrigues, DC); Siddiqui, Danyal A.; Sridhar, Sathyanarayanan; Wang, Frederick; Jacob, Joel J.; Rodrigues, Danieli C.Zirconia (ZrO₂) is an emerging alternative to titanium for dental implant systems due to its material properties including high mechanical strength and chemical stability. However, oral environmental factors such as bacterial adhesion and mechanical fatigue may trigger low-temperature degradation of ZrO₂, leading to reduced mechanical strength and potential implant fracture. Although failure modes of ZrO₂ in orthopedic applications have been studied, they have yet to be thoroughly investigated in the context of dental implant systems. Thus, the goal of the present study was to assess the surface of ZrO₂ dental implants for signs of degradation after exposure to oral bacteria and oral bacteria in combination with mechanical fatigue. ZrO₂ dental implants were subjected to 30-day immersion in (i) early or (ii) late colonizing oral bacteria or (iii) were mechanically loaded for 2 × 106 cycles with oral bacteria in circulation. Optical microscopy, Raman microscopy, and X-ray photoelectron spectroscopy (XPS) were used to evaluate the surface morphology, phase composition, and chemical composition, respectively. Post-immersion, all implants exhibited minimal changes in surface features, and all loaded implants survived cyclic fatigue tests. All implants had <1% monoclinic phase at the collar, junction, and screw regions, excluding the screw threads, for which monoclinic phase was significantly higher but <10%. XPS revealed an increase in carbon- and nitrogen-based organic debris on the implants exposed to early colonizers as compared to those immersed in late colonizers or synergistically with mechanical loading. Within the limitations of the present study, ZrO₂ is a suitable alternative material for dental implant systems based on its ability to resist both physical and chemical degradation imposed by oral bacteria and applied cyclic loads. © 2019 American Chemical Society.Item Dicationic Imidazolium-Based Ionic Liquids: A New Strategy for Non-Toxic and Antimicrobial Materials(Royal Soc Chemistry) Gindri, Izabelle M.; Siddiqui, Danyal A.; Bhardwaj, Pooja; Rodriguez, Lucas C.; Palmer, Kelli L.; Frizzo, Clarissa P.; Martins, Marcos A. P.; Rodrigues, Danieli C.; Palmer, Kelli L.; Rodrigues, Danieli C.New dicationic imidazolium-based ionic liquids (ILs) were synthesized, characterized and tested in regards to cytotoxicity and antimicrobial activity. Insertion of a new cationic head and use of organic anions increased the biocompatibility of the ILs developed. IC₅₀ (concentration necessary to inhibit 50% of enzymatic activity) values obtained were considerably higher than those described for monocationic ILs, which indicates an improvement in cytocompatibility. Antimicrobial activity against bacterial species of clinical relevance in wounds and the oral environment was tested. The results showed that ILs were effective in inhibiting bacterial growth even below the minimum inhibitory concentration (MIC). It was observed that structural features that confer higher hydrophobicity to ILs decreased both the IC₅₀ and MIC simultaneously. However, it was possible to establish an equilibrium between those two effects, which gives the safe range of concentrations that ILs can be employed. The results demonstrated that the dicationic-imidazolium-based ILs synthesized may constitute a potent strategy for applications requiring non-toxic materials exhibiting antimicrobial activity.Item Effects of Titanium Oxide Surface Properties on Bone-Forming and Soft Tissue-Forming Cells(Wiley) Wheelis, Sutton E.; Montaño-Figueroa, Ana Gabriela; Quevedo-Lopez, Manuel A.; Rodrigues, Danieli C.; 0000-0003-4068-9896 (Wheelis, SE); 0000-0002-0389-0833 (Rodrigues, DC); Wheelis, Sutton E.; Montaño-Figueroa, Ana Gabriela; Quevedo-Lopez, Manuel A.; Rodrigues, Danieli C.Background: Previous studies have concluded that certain titanium oxide (TiO₂) surface properties promote bone-forming cell attachment. However, no comprehensive studies have investigated the effects of TiO₂ surface and film morphology on hard and soft tissues. Purpose: The aim of this study is to understand the effects of TiO₂ morphology on the proliferation and differentiation of murine preosteoblasts (MC3T3-E1) and proliferation of human gingival fibroblasts (HGF-1) using in vitro experiments. Materials and Methods: Samples were fabricated with several TiO₂ thickness and crystalline structure to mimic various dental implant surfaces. in vitro analysis was performed for 1, 3, and 7 days on these samples to assess the viability of MC3T3-E1 and HGF-1 cells in contact with the modified oxide surfaces. Results: Results showed that HGF-1 cells exhibited no significant difference in viability on modified oxide surfaces versus a titanium control across experiments. MC3T3-E1 cells exhibited a significantly higher viability for the modified oxide surface in 1 day experiments, but not in 3 or 7 day experiments. Alkaline phosphatase expression in MC3T3-E1 was not significantly different on modified oxide surfaces versus the control across all experiments. A slight positive trend in viability was observed for cells in contact with rougher modified oxide surfaces versus a titanium control in both cell types. Conclusions: These observations suggest that crystallinity and thickness do not affect the long-term viability of hard or soft tissue cells when compared to a cpTi surface. Therefore, treatments like anodization on implant components may not directly affect the attachment of hard or soft tissue cells in vivo. © 2018 Wiley Periodicals, Inc.Item Evaluation of Mammalian and Bacterial Cell Activity on Titanium Surface Coated with Dicationic Imidazolium-Based Ionic Liquids(Royal Soc Chemistry, 2016-04-04) Gindri, Izabelle M.; Palmer, Kelli L.; Siddiqui, Danyal A.; Aghyarian, Shant; Frizzo, Clarissa P.; Martins, Marcos A. P.; Rodrigues, Danieli C.; 0000-0002-7343-9271 (Palmer, KL); Gindri, Izabelle M.; Palmer, Kelli L.; Siddiqui, Danyal A.; Aghyarian, Shant; Rodrigues, Danieli C.This work presents a new strategy to protect titanium surfaces against bacterial colonization and biofilm formation using dicationic imidazolium-based ionic liquid coatings. Ionic liquids (ILs) were designed as multi-functional coatings and their compatibility with human gingival fibroblasts (HGF-1) and preosteoblast (MC3T3-E1) cells was investigated. Results demonstrated that IL coatings were stable and present on titanium surfaces after 7 days of immersion and showed that using phenylalanine as the anionic moiety allowed for cell proliferation and differentiation on titanium surface while also providing strong antimicrobial and anti-biofilm activity against bacterial strains relevant to the oral environment (Streptococcus sp.). Strains such as Streptococcus mutans, S. sanguinis, S salivarius, S. gordonii and S. uberis are known to colonize the surface of dental implants in the early stages after implantation (early colonizers), compromising the success of these devices. The "race for the surface" between cells and bacteria was established by correlating results obtained from cell proliferation (epithelial and osteoblast) and differentiation (osteoblast) studies with that of antimicrobial activity against early bacterial colonizers.Item Evaluation of Oral Microbial Corrosion on the Surface Degradation of Dental Implant Materials(Wiley, 2018-08-13) Siddiqui, Danyal A.; Guida, Lidia; Sridhar, Sathyanarayanan; Valderrama, Pilar; Wilson, Thomas G., Jr.; Rodrigues, Danieli C.; 0000-0002-0389-0833 (Rodrigues, DC); Rodrigues, Danieli C.; Siddiqui, Danyal A.; Guida, Lidia; Sridhar, SathyanarayananBackground: Titanium (Ti) dominates as the material of choice for dental implant systems. Recently, titanium-zirconium alloy (TiZr) and zirconia (ZrO₂) have emerged as alternative materials due to higher mechanical strength and lower corrosion susceptibility. Oral pathogenic bacteria can colonize Ti surfaces, leading to surface degradation, which has yet to be investigated on TiZr and ZrO₂. The aim of this study was to compare in vitro oral bacterial adhesion and subsequent surface degradation on commercial Ti, TiZr, and ZrO₂ implants. Methods: Ti, TiZr, and ZrO₂ implants with sandblasted, acid-etched (SLA) surfaces in addition to modified SLA-treated (modSLA) Ti implants (n = 3) were immersed for 30 consecutive days in Streptococcus polyculture. Post-immersion, adherent bacterial count was quantified. Optical microscopy was used to assess qualitative degradation and score Ti-based implants based on degree of surface damage while electrochemical testing quantified corrosion behavior. Analysis of variance followed by post-hoc Tukey test was used to statistically compare quantitative results (alpha = 0.05). Results: Ti-SLA, Ti-modSLA, and TiZr-SLA implants exhibited localized features characteristic of corrosion attack while ZrO₂-SLA implants experienced minimal changes in surface morphology as compared to non-immersed control. Corrosion features were more numerous on Ti-modSLA implants but smaller in size as compared with those on Ti-SLA and TiZr-SLA implants. No significant differences in corrosion resistance (polarization resistance and corrosion rate) were observed between Ti-SLA, Ti-modSLA, and TiZr-SLA implants. Conclusion: TiZr and ZrO₂ dental implant surfaces were not more susceptible to colonization and surface degradation by oral Streptococcus species than commercially pure Ti implants.Item HGMB1 and RAGE as Essential Components of Ti Osseointegration Process in Mice(Frontiers Media S.A., 2019-04-05) Biguetti, C. C.; Cavalla, F.; Silveira, E. V.; Tabanez, A. P.; Francisconi, C. F.; Taga, R.; Campanelli, A. P.; Trombone, A. P. F.; Rodrigues, Danieli C.; Garlet, G. P.; Rodrigues, Danieli C.The release of the prototypic DAMP High Mobility Group Box 1 (HMGB1) into extracellular environment and its binding to the Receptor for Advanced Glycation End Products (RAGE) has been described to trigger sterile inflammation and regulate healing outcome. However, their role on host response to Ti-based biomaterials and in the subsequent osseointegration remains unexplored. In this study, HMGB1 and RAGE inhibition in the Ti-mediated osseointegration were investigated in C57Bl/6 mice. C57Bl/6 mice received a Ti-device implantation (Ti-screw in the edentulous alveolar crest and a Ti-disc in the subcutaneous tissue) and were evaluated by microscopic (microCT [bone] and histology [bone and subcutaneous]) and molecular methods (ELISA, PCR array) during 3, 7, 14, and 21 days. Mice were divided into 4 groups: Control (no treatment); GZA (IP injection of Glycyrrhizic Acid for HMGB1 inhibition, 4 mg/Kg/day); RAP (IP injection of RAGE Antagonistic Peptide, 4 mg/Kg/day), and vehicle controls (1.5% DMSO solution for GZA and 0.9% saline solution for RAP); treatments were given at all experimental time points, starting 1 day before surgeries. HMGB1 was detected in the Ti-implantation sites, adsorbed to the screws/discs. In Control and vehicle groups, osseointegration was characterized by a slight inflammatory response at early time points, followed by a gradual bone apposition and matrix maturation at late time points. The inhibition of HMGB1 or RAGE impaired the osseointegration, affecting the dynamics of mineralized and organic bone matrix, and resulting in a foreign body reaction, with persistence of macrophages, necrotic bone, and foreign body giant cells until later time points. While Control samples were characterized by a balance between M1 and M2-type response in bone and subcutaneous sites of implantation, and also MSC markers, the inhibition of HMGB1 or RAGE caused a higher expression M1 markers and pro-inflammatory cytokines, as well chemokines and receptors for macrophage migration until later time points. In conclusion, HMGB1 and RAGE have a marked role in the osseointegration, evidenced by their influence on host inflammatory immune response, which includes macrophages migration and M1/M2 response, MSC markers expression, which collectively modulate bone matrix deposition and osseointegration outcome. Copyright ©2019 The AuthorsItem In Vitro Evaluation of Cell Compatibility of Dental Cements Used with Titanium Implant Components(Wiley, 2019-02) Marvin, Jason C.; Gallegos, Silvia I.; Parsaei, Shaida; Rodrigues, Danieli C.; 0000-0002-0389-0833 (Rodrigues, DC); Marvin, Jason C.; Gallegos, Silvia I.; Parsaei, Shaida; Rodrigues, Danieli C.Purpose To evaluate the biocompatibility of five dental cement compositions after directly exposing human gingival fibroblast (HGF) and MC3T3-E1 preosteoblast cells to cement alone and cement applied on commercially pure titanium (cpTi) specimens. Materials and Methods Nanostructurally integrated bioceramic (NIB), resin (R), resin-modified glass ionomer (RMGIC), zinc oxide eugenol (ZOE), and zinc phosphate (ZP) compositions were prepared according to the respective manufacturer's instructions. Samples were prepared in cylindrical Teflon molds or applied over the entire surface of polished cpTi discs. All samples were cured for 0.5, 1, 12, or 24 hours post-mixing. Direct contact testing was conducted according to ISO 10993 by seeding 6-well plates at 350,000 cells/well. Plates were incubated at 37 degrees C in a humidified atmosphere with 5% CO2 for 24 hours before individually plating samples and cpTi control discs. Plates were then incubated for an additional 24 hours. Microtetrazolium (MTT) cell viability assays were used to measure sample cytotoxicity. Results For samples that cured for 24 hours prior to direct contact exposure, only NIB and ZP cements when cemented on cpTi demonstrated cell viability percentages above the minimum biocompatibility requirement (>= 70%) for both the investigative cell lines. R, RMGIC, and ZOE cements exhibited moderate to severe cytotoxic effects on both cell lines in direct contact and when cemented on cpTi specimens. For HGF cells, ZOE cemented-cpTi specimens exhibited significantly decreased cytotoxicity, whereas RMGIC cemented-cpTi specimens exhibited significantly increased cytotoxicity. Conclusions Despite previous studies that showed enhanced cpTi corrosion activity for fluoride-containing compositions (NIB and ZP), there was no significant difference in cytotoxicity between cement alone and cemented-cpTi. In general, the MC3T3-E1 preosteoblast cells were more sensitive than HGF cells to cement composition. Ultimately, cement composition played a significant role in maintaining host cell compatibility. Results of this work help illustrate the impact of different cement formulations on host cell health and emphasize the need for understanding material properties when selecting certain formulations of dental cements, which can ultimately influence the survival of dental implant systems.Item Investigation of Composite Cements Containing Calcium Phosphate and Release Modulating Phases as Antibiotic Delivery Systems for Prosthetic Joint Infection(2017-05) Jayaraman, Vidyalakshmi; Rodrigues, Danieli C.The role of bone cements in averting orthopedic infections has been well reported. As bioinert polymeric materials undergoing considerable degree of time-dependent mechanical and biochemical degradation, cements have been used as carriers of antibiotics which can be released in situ to prevent or control joint infections. However, the effectiveness of cements in providing long-term, reliable prophylaxis is debatable because of cement-related factors like intrinsic hydrophobicity and minimal porosity, which have been critical in discouraging drug release. It has also been shown that biodegradable additives like calcium phosphates and polysaccharides/sugars can be added to cements to enhance the degree of drug elution by inducing porosity. This work presents the fundamental characterization of gentamycin loaded pre-mixed bone cements containing the additives brushite and lactose, as drug delivery systems for infection management. In vitro analysis of degree of drug release, compressive strength, bactericidal efficacy and bone cell compatibility were performed to understand the impact of the additives on these functional requirements of antibiotic –loaded bone cement.Item Investigation of Titanium Oxide Characteristics on Healing Abutments: Retrieval Characterization and Soft-Tissue Compatibility(2017-08) Wheelis, Sutton E.; Rodrigues, Danieli C.Titanium implant healing abutments (IHAs) are a temporary component of the dental implant system that have a vital role in soft tissue healing and shaping after implant body placement. A large amount of studies have been dedicated to investigating dental implant body performance, however little focus is placed on the IHA. Unlike the implant body, these devices are exposed to both the oral environment and acute inflammation post-implantation, producing conditions known to cause early implant failure. In addition, they are color coded with anodization during manufacturing, with no regard to how this surface modification affects the stability or efficacy of the device. Therefore, it is crucial to understand the behavior of IHA during implantation, and the response of soft tissue to these modified titanium oxide surfaces. Anodized IHAs were subjected to surface characterization pre-and post-implantation in patients to elucidate the effects of the oral environment on HA surfaces. Changes in surface crystallinity, morphology, elemental composition, and electrochemical properties were monitored to assess HA surface stability. To evaluate soft tissue response to these materials, titanium oxide samples were fabricated to have varied titanium oxide thickness and crystalline structure to mimic IHA surfaces. In vitro analysis was performed on these samples to assess the viability of HGF-1 cells in contact with the modified oxide surfaces.Item Multifaceted Roles of Environmental Factors toward Dental Implant Performance: Observations from Clinical Retrievals and In Vitro Testing(Elsevier Inc.) Sridhar, Sathyanarayanan; Wang, Frederick; Wilson, T. G., Jr.; Valderrama, P.; Palmer, Kelli; Rodrigues, Danieli C.; Sridhar, Sathyanarayanan; Wang, Frederick; Palmer, Kelli; Rodrigues, Danieli C.Objective: Oral bacteria and periodontal pathogen have been predominantly linked with early- and late- stage failures of titanium (Ti) dental implants (DI) respectively. This study is based on the hypothesis that bacterial colonization can damage the surface oxide (TiO₂) layer. Early-failed DI were compared with DI post-in vitro immersion in early colonizing oral bacteria; late failed DI were weighed against DI immersed in late colonizing anaerobic pathogens. Methods: Retrieval analysis: Seven early- stage failed implants with five of them connected to healing abutments (HAs), and ten late- stage failed retrievals were subjected to surface analysis. Bacteria immersion test: Three dental implants each were immersed in polycultures containing (i) early colonizers (Streptococcus mutans, S. salivarius, S. sanguinis) (ii) late colonizers (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans). The implants were immersed for 30 days to simulate the healing period and bacterial biofilm adhesion. Optical microscope, x-ray photoelectron spectroscopy (XPS), and electrochemical test were performed to analyze the surface- morphology, chemistry, and potential respectively. Results: Early colonizers inflicted surface morphological damage (discoloration and pitting). Even though, XPS detected thinner oxide layer in 2/3 early retrievals, XPS and electrochemical tests illustrated that the TiO₂ layer was intact in HAs, and in DI post- immersion. Late colonizers also caused similar morphological damage (discoloration and pitting), while mechanical wear was evident with scratches, cracks, and mechanical fracture observed in late-stage retrievals. XPS indicated thinner oxide layer in late-stage retrievals (3/4), and in DI post-immersion in late colonizers. This was reflected in electrochemical test results post-immersion but not in the late-stage retrievals, which suggested an intact surface with corrosion resistance. Significance: This study concluded that bacteria could negatively affect implant surface with late colonizers demonstrating more pronounced damage on the surface morphology and chemistry. ©2018 The Academy of Dental MaterialsItem Novel Chlorhexidine-Loaded Polymeric Nanoparticles for Root Canal TreatmentQuiram, Gina; Montagner, Francisco; Palmer, Kelli L.; Stefan, Mihaela C.; Washington, Katherine E.; Rodrigues, Danieli C.; Quiram, Gina; Palmer, Kelli L.; Stefan, Mihaela C.; Washington, Katherine E.; Rodrigues, Danieli C.Persistence of microorganisms in dentinal tubules after root canal chemo-mechanical preparation has been well documented. The complex anatomy of the root canal and dentinal buffering ability make delivery of antimicrobial agents difficult. This work explores the use of a novel trilayered nanoparticle (TNP) drug delivery system that encapsulates chlorhexidine digluconate, which is aimed at improving the disinfection of the root canal system. Chlorhexidine digluconate was encapsulated inside polymeric self-assembled TNPs. These were self-assembled through water-in-oil emulsion from poly(ethylene glycol)-b-poly(lactic acid) (PEG-b-PLA), a di-block copolymer, with one hydrophilic segment and another hydrophobic. The resulting TNPs were physicochemically characterized and their antimicrobial effectiveness was evaluated against Enterococcus faecalis using a broth inhibition method. The hydrophilic interior of the TNPs successfully entrapped chlorhexidine digluconate. The resulti ng TNPs had particle size ranging from 140–295 nm, with adequate encapsulation efficiency, and maintained inhibition of bacteria overItem Surface Characterization of Retrieved Metal-On-Metal Total Hip Implants from Patients with Adverse Reaction to Metal Debris(MDPI AG) Burbano-Salazar, Maria; Russell, R.; Huo, M.; Welch, R.; Roy, Diana; Rodrigues, Danieli C.The use of metal-on-metal (MoM) total hip implants has decreased recently due to reports of high failure rates and adverse local tissue reaction (ALTR). It has been hypothesized that wear metal debris released from CoCr bearing surfaces may provoke delayed hypersensitivity reactions. The goal of this study is to evaluate the microscopic bearing surface characteristics of implants revised due to evidence of ALTR. The bearing surface of each head and cup was analyzed using multiple microscopy techniques for characterization of the surface features. The presence of severe mechanical scratching was a common characteristic found in all of the implants evaluated. Mechanical factors seemed to be the prevalent failure mode related to the appearance of ALTR with this particular set of retrieved implants.Item Synthesis and Characterization of Chlorhexidine-Containing Polymeric Trilayered Nanoparticle for Root Canal Treatment(2017-05) Quiram, Gina J.; Rodrigues, Danieli C.Disinfection during a root canal treatment is limited due to anatomical complexities. Better carrier systems of antimicrobial agents are needed to ensure efficient bacteria eradication. Block copolymer nanoparticles have great potential as drug delivery vehicles because of their small size that allows accumulation of drug at target sites and ease of synthesis. This study sought to use block copolymer nanoparticles to improve drug bioavailability, direct drug distribution to a precise site, and sustain release after endodontic procedures. To accomplish this chlorhexidine-containing nanoparticles were designed to steadily release the drug. The drug chlorhexidine was encapsulated in poly(ethylene glycol)–block–poly(L-lactide) (PEG–b–PLA) to synthesize bilayer and trilayered nanoparticles. These polymeric nanoparticles were characterized for size, morphology, and drug loading proficiency. In conclusion, these nanoparticles were found to be small enough to penetrate dentin tubules, dispersed well in a hydrogel matrix carrier system, and enhanced bacterial inhibition over longer periods of time.