Plaque Adhesion Research Articles

Effect of surface textures fabricated by two-dimensional ultrasonic vibration-assisted milling on the key surface properties of dental ceramics

The exceptionally high hardness and active plaque adhesion ability of 3Y-TZP ceramics often cause lots of oral diseases. This work intends to enhance the service performance of such ceramic dentures in human oral cavity by surface texturing technique. Efforts have been made to tackle the surface texture formation mechanism under 2D-UVAM process and establish the connection between the key surface properties and texture morphologies. The impacts of cutting parameters, vibration parameters, and tool geometry parameters on texture morphologies were rigorously studied. The coupling effect of wettability, antibacterial activity, and frictional performance of textured ceramic surfaces was also investigated. The acquired results indicate that the fish-scale texture with high density helps to enhance the hydrophobicity of the zirconia ceramics, while the wavy texture with low density promotes the ceramic material towards a hydrophilic direction. The antibacterial activity is highly related to wettability. The larger contact angle generally means the more pronounced inhibition effect on plaque adhesion. The wear of natural teeth decreases significantly after introducing textures on the ceramic surfaces, but the wear amount is not sensitive to wettability. Therefore, the hydrophobic surface can simultaneously improve the antibacterial characteristics of 3Y-TZP ceramics and its tribological compatibility with the natural teeth.

Surface Pre-Reacted Glass-Ionomer Eluate Suppresses Osteoclastogenesis through Downregulation of the MAPK Signaling Pathway.

Surface pre-reacted glass-ionomer (S-PRG) is a new bioactive filler utilized for the restoration of decayed teeth by its ability to release six bioactive ions that prevent the adhesion of dental plaque to the tooth surface. Since ionic liquids are reported to facilitate transepithelial penetration, we reasoned that S-PRG applied to root caries could impact the osteoclasts (OCs) in the proximal alveolar bone. Therefore, this study aimed to investigate the effect of S-PRG eluate solution on RANKL-induced OC-genesis and mineral dissolution in vitro. Using RAW264.7 cells as OC precursor cells (OPCs), TRAP staining and pit formation assays were conducted to monitor OC-genesis and mineral dissolution, respectively, while OC-genesis-associated gene expression was measured using quantitative real-time PCR (qPCR). Expression of NFATc1, a master regulator of OC differentiation, and the phosphorylation of MAPK signaling molecules were measured using Western blotting. S-PRG eluate dilutions at 1/200 and 1/400 showed no cytotoxicity to RAW264.7 cells but did significantly suppress both OC-genesis and mineral dissolution. The same concentrations of S-PRG eluate downregulated the RANKL-mediated induction of OCSTAMP and CATK mRNAs, as well as the expression of NFATc1 protein and the phosphorylation of ERK, JNK, and p38. These results demonstrate that S-PRG eluate can downregulate RANKL-induced OC-genesis and mineral dissolution, suggesting that its application to root caries might prevent alveolar bone resorption.

Multi-bionic strategy combined with surface for anti-fouling

More and more bio-inspired methods are used to obtain anti-fouling surfaces, in which the structure plays a pivotal role in bionic coatings. It is a trend to prepare dynamic anti-fouling surfaces to improve the anti-fouling performance of the surface and synthesis the large-scale surface. Therefore, based on the special multilevel structure of Folium Sennae, the Folium Sennae-inspired surface was prepared and modified by the active molecule from Folium Sennae here (GFSF-x, AGFSF-y). Based on the excellent anti-fouling of Folium Sennae-inspired surfaces, a series of arrayed dynamic surfaces with structure-controlling liquid behavior were prepared (VMxFy). Among them, AGFSF-5 shows an excellent anti-fouling performance, whose anti-diatom attachment rate is as high as 97.8 %. The arrayed-structured coatings (MxFy) exhibit an ability to hinder the adhesion of plaque in mussel adhesion experiments. In addition, the inhibition attachment rate of diatoms of AGMPF-4 (MxFy was subjected to optimal concentration assembly) is 83.7 %, while it is 99.5 % of VMxFy. Besides, the liquid grows dynamically along the arrayed structure, and the height of VMNF-4 increased from 15.12 to 206.26 μm. The bio-inspired surfaces based on the two methods here show outstanding anti-fouling ability, in particular, the arrayed-structured surface controlling liquid behavior. This study provides a new idea for the construction of dynamic structural surfaces and shows the practical application potential due to its ability to large-scale surface texture.

Quasi-static responses of marine mussel plaques detached from deformable wet substrates under directional tensions

Quantifying the response of marine mussel plaque attachment to wet surfaces remains a significant challenge to a mechanistic understanding of plaque adhesion. Here, we develop a novel, customized microscope system, combined with two-dimensional in situ digital image correlation (DIC), to quantify the in-plane deformation of a deformable substrate that interacts with a mussel plaque under directional tension. By examining the strain field within the substrate, we acquired an understanding of the mechanism by which in-plane traction forces are transmitted from the mussel plaque to the underlying substrate. Finite-element (FE) models were developed to assist in the interpretation of the experimental measurement. Our study revealed a synergistic effect of pulling angle and substrate stiffness on plaque detachment, with mussel plaques anchoring to a ‘stiff’ substrate at small pulling angles, i.e. natural anchoring angles, having mechanical advantages with higher load-bearing capacity and less plaque deformation. We identify two distinct failure modes, i.e. shear-traction-governed failure (STGF) and normal-traction-governed failure (NTGF). It was found that increasing the stiffness of the substrate or reducing the pulling angle results in a change of the failure mode from NTGF to STGF. Our findings offer new insights into the mechanistic understanding of mussel plaque–substrate interaction, providing a plaque-inspired strategy to develop high-performance and artificial wet adhesion.

Hyposalinity stress reduces mussel byssus secretion but does not cause detachment

Environmental stressors such as salinity fluctuations can significantly impact the ecological dynamics of mussel beds. The present study evaluated the influence of hyposalinity stress on the detachment and survival of attached mussels by simulating a mussel farming model in a laboratory setting. Byssus production and mechanical properties of thread in response to varying salinity levels were assessed, and histological sections of the mussel foot were analyzed to identify the changes in the byssus secretory gland area. The results showed that hyposalinity stress (20 and 15 psu) led to a significant decrease in mussel byssus secretion, delayed initiation of new byssus production, and reduced plaque adhesion strength and breaking force of byssal threads compared to the control (30 psu) (p < 0.05). The complete suppression of byssal thread secretion in mussels under salinity conditions of 10 and 5 psu, leading to lethality, indicates the presence of a blockade in byssus secretion when mussels are subjected to significant physiological stressors. Histological analysis further demonstrated a decrease in the percentage of foot secretory gland areas in mussels exposed to low salinities. However, contrary to expectations, the study found that mussels did not exhibit marked detachment from ropes in response to the reduced salinity levels during one week of exposure. Hyposalinity stress exposure reduced the byssal secretion capacity and the mechanical properties of threads, which could be a cause for the detachment of suspension-cultured mussels. These results highlight the vulnerability of mussels to hyposalinity stress, which significantly affects their byssus mechanical performance.

Surface Roughness Evaluation of Pre- Versus Post-Crystallization Polish of Two High-Strength Silicate Ceramics for Chairside CAD/CAM Technology

This in vitro study evaluated the surface roughness (Sa) of two high-strength silicate ceramics, lithium disilicate IPS e.max CAD, Ivoclar Vivadent (LDS group), and zirconia-reinforced lithium silicate Vita Suprinity, VITA Zahnfabrik (ZLS group). The surface roughness was investigated before and after milling using different polishing systems and timings relative to the final crystallization of the ceramics. Forty-eight samples per group were polished by a single calibrated operator using two polishing systems: Dialite LD (Brasseler) and Lithium Silicate Polishers (Meisinger) for the LDS group and Dialite LD (Brasseler) and Vita Suprinity Polishing Set Technical (VITA Zahnfabrik) for the ZLS group, both pre- and post-crystallization. Surface roughness was measured using a confocal laser microscope (OLS4000 LEXT/Olympus), with scanning electron microscopy (SEM) used to evaluate surface morphological changes. Significant differences in Sa values were found between baseline groups, with ZLS exhibiting lower values. All polishing methods significantly reduced surface roughness compared to baseline (p ≤ 0.05). No significant differences were found in LDS samples when polishing pre- or post-crystallization (p = 0.129), while for ZLS samples, post-crystallization polishing achieved significantly smoother surfaces (p &lt; 0.001). The study concluded that the choice of polishing system and timing did not significantly affect surface roughness for LDS. However, it is recommended that post-crystallization polishing be performed for the optimal smoothness of ZLS. This study aimed to evaluate the post-milling polishing procedures of CAD/CAM high-strength restorations, emphasizing the importance of an optimal surface roughness to prevent issues such as increased risk of abrasion on opposing teeth, enhanced plaque adhesion, and mechanical failures. Investigating these polishing techniques enables clinicians to optimize clinical performance, thereby improving the quality and longevity of high-strength silicate ceramics.

Comparison of plaque control record measurements obtained using intraoral scanner and direct visualization.

Intraoral scanner (IOS) can acquire three-dimensional color images of teeth. Thus, the detection of areas with plaque adhesion stained by plaque-disclosing solutions using an IOS could be a potential oral hygiene evaluation method. This study aimed to verify the usefulness of obtaining O'Leary's plaque control record (PCR) measurements using an IOS in clinical practice. Twenty patients with >20% PCR measurements who underwent oral prophylaxis were enrolled in this study. A plaque-disclosing gel was applied to stain the areas with plaque adhesion, and the dentition was scanned using the IOS. The PCR values obtained via the direct method and those obtained using the digital image were compared for the entire dentition, maxillary total area, the labial and palatal aspects of the maxillary anterior teeth, the buccal and palatal aspects of the maxillary posterior teeth, mandibular total area, the labial and lingual aspects of the mandibular anterior teeth, and the buccal and lingual aspects of the mandibular posterior teeth. The IOS group tended to have higher values than the direct observation group. The labial and palatal aspect of the maxillary anterior teeth, the labial and lingual aspects of the mandibular anterior teeth did not differ significantly between the groups. Plaque adhesion was visualized easily and conclusively using an IOS. As the large tip size often hinders its use, it is necessary to develop a smaller IOS tip in the future.

Novel antibacterial titanium implant healing abutment with dimethylaminohexadecyl methacrylate to combat implant-related infections

ObjectiveImplant-related infections from the adhesion and proliferation of dental plaque are a major challenge for dental implants. The objectives of this study were to: (1) develop novel antibacterial titanium (Ti) healing abutment; (2) investigate the inhibition of implant infection-related pathogenic bacteria and saliva-derived biofilm, and evaluate the biocompatibility of the new material for the first time. MethodsDimethylaminohexadecyl methacrylate (DMAHDM) and hydroxyapatite (HAP) were polymerized via polydopamine (PDA) on Ti. Staphylococcus aureus (S. aureus), Streptococcus sanguinis (S. sanguinis) and human saliva-derived biofilms were tested. After 4 weeks of DMAHDM release, the antibacterial efficacy of the DMAHDM remaining on Ti surface and the DMADHM in medium was tested. Biocompatibility was determined using human gingival fibroblasts (HGFs) and periodontal ligament stem cells (PDLSCs). ResultsThe DMAHDM-loaded coating filled into the nano-voids in Ti surfaces. The modified Ti showed potent antibacterial activity, reducing the CFU of S. aureus, S. sanguinis and saliva-derived biofilms by 8, 7 and 4 log, respectively (P < 0.05). After 4 weeks of release, the modified Ti was still able to reduce S. aureus and S. sanguinis biofilm CFU by 1–3 log (P < 0.05). This provided strong antibacterial function for more than 4 weeks, which were the high-risk period for implant infections. The new material showed excellent biocompatibility when compared to control (P > 0.05). ConclusionNovel DMAHDM-loaded Ti healing abutment had strong antibacterial effects, reducing biofilm CFUs by orders of magnitude, and lasting for over four weeks to cover the high-risk period for implant infections. The novel antibacterial Ti is promising to combat implant-related infections in dental, craniofacial and orthopedic applications.

THE EFFECT OF DENTAL IMPLANTS ON INCREASING THE COLONIZATION RATE OF AEROBIC BACTERIA IN THE ORAL CAVITY

Background and aims: Dental implants' principal function is to support artificial teeth. The physiological process by which bones firmly adhere to the surface of various ceramics and metals, such as titanium, is what leads to the emergence of modern dental implants, and there may be negative effects of these implants on the balance in the bacterial numbers in the mouth. Therefore, this study compared the colony forming unit (CFU) of oral bacteria from the buccal mucosa and buccal tongue between patients who had dental implants and healthy volunteers without dental implants. Methods: In this study, 36 people with dental implants and 36 people without dental implants were both included. Following serial dilutions were made and distributed on blood agar, samples were grown in Brain Heart Infusion Broth (BHI). When a single layer of bacteria developed on blood agar at any dilution level, CFU was estimated. Version 7 of Epi-info Statistics software was used to analyze the data. In each graph, the results were presented as mean standard error of the mean (SEM), and in the table, as mean and standard deviation (SD). Collected data were normally distributed and an independent T-test was used to compare different means of oral CFU bacteria between control and test groups of buccal mucosa and lingual mucosa. Results: For non-implant controls the values for buccal mucosa of bacterial counts were slightly lower than that of the implant patient’s buccal mucosa. There was a significant correlation between the increase of aerobic bacterial colonization of the tongue with the implants where the mean±SD was 196.8±12.9 CFU/ml greater than 183.4±9.1 CFU/ml for the normal controls; indicating the enhancement of the effect of the implant in the heavy colonization of bacteria in the oral cavity among implant patient group (p&lt;0.0001). There was a significant association between ≥5 implants and heavy bacterial colonization of the oral cavity with the mean±SD being 214±13.9 CFU/mL vs. 192.85±4.44 CFU/mL for the two-implant composite patient; p=0.027. Additionally, there was a strong correlation between the duration of 13–24 months since implant placement and decreased bacterial colonization of the oral cavity with the mean±SD being 193.2±10.3 CFU/mL vs. 209.6±13.8 CFU/mL for ≤ 12 months; p=0.005. Conclusion: Patients with implants had greater lingual buccal tongue CFU readings than non-implant patients, suggesting that implants are more prone to plaque adhesion. Dental implants, particularly those associated with five implants or more and those recently placed, increased the amount of bacteria leading to heavily colonized of the oral cavity. Peer Review History: Received: 11 March 2023; Revised: 26 April; Accepted: 29 June 2023, Available online: 15 July 2023 Academic Editor: Dr. Iman Muhammad Higazy, National Research Center, Egypt, imane.higazy@hotmail.com Received file: Reviewer's Comments: Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Omnia Momtaz Al-Fakharany, Tanta, University, Eygpt, amina.elfakharany@pharm.tanta.edu.eg Dr. Mohaddese Mahboubi, Alzahra University, Tehran, Iran, mahboubi@barijessence.com

Efficacy of cetylpridium chloride mouthwash compared to povidone iodine on oral flora for perioperative patient care: A randomized controlled feasibility study

ObjectivesPerioperative oral management (POM) reduces the risk of postoperative pneumonia. Povidone iodine (PVP-I) is used in the self-care aspect of POM in Japan; however, its bactericidal capability may be reduced by dilution or saliva. Thus, we conducted a randomized parallel controlled feasibility study to evaluate the effects of 0.05% cetylpyridinium chloride (CPC) mouthwash compared to PVP-I gargle on the oral flora as perioperative self-care, in addition to brushing. MethodsA total of 100 patients scheduled for surgery, except in the head and neck region, under general anesthesia were randomly assigned into the CPC (n = 51) or PVP-I (n = 49) groups. Patients underwent clinical assessment and professional oral care (POC) before surgery, then brushed and used CPC or PVP-I products. Buccal mucosa, tongue coating, and saliva samples were collected six times in perioperative period. All samples were analyzed using 16 S rRNA gene sequencing and quantitative polymerase chain reaction. ResultsClinical indicators and samples from 83 participants (42 and 41 in the CPC and PVP-I groups, respectively) were analyzed. Reduced dental plaque adhesion and gingival bleeding and improved total bacterial counts were observed in both groups one week after surgery. In the CPC group, Streptococcus was suppressed until one week after surgery compared with that in the PVP-I group. ConclusionsOur study supports the feasibility of a full-scale randomized controlled trial to determine the effects of CPC mouthwash and PVP-I gargle on the oral flora. A CPC mouthwash may maintain the antibiotic effect longer than a PVP-I gargle.

Indocyanine green-mediated antimicrobial photodynamic therapy as an adjunct to non-surgical periodontal treatment: a systematic review and meta-analysis.

Indocyanine green-mediated antimicrobial photodynamic therapy as an adjunct to non-surgical periodontal treatment: a systematic review and meta-analysis.

Avaliação do esmalte dentário de cão por microscopia eletrônica de varredura após diferentes tipos de polimento

Abstract Polishing is an important procedure which takes part in the periodontal disease treatment, being commonly performed with the help of prophylactic paste and provides smoothing of the tooth surface, hindering the adhesion of new plaque. With this study we aimed to evaluate by means of scanning electron microscopy (SEM), the effects of dental polishing observing, qualitatively, the effectiveness and the damage, in three distinct treatments after calculus removal. Twenty (20) teeth were used (four of each dog), from which were obtained three samples each. The sixty samples were distributed into three groups (G0= tooth segmentation submitted to prophylaxis without polishing; G1= vestibular surface prophylaxis followed by polishing with the use of Defengy OC® and G2= vestibular surface prophylaxis followed by polishing with the use of pumice and fluorine gel). The samples were prepared and sent to images execution via SEM. These images, with enlargement of 100x and 500x, were evaluated and the classification averages were obtained. The statistical analysis of these averages was made through the Friedman nonparametric test using the software R. Statistical differences were observed (P&lt;0,05) between groups 0 and 1 in the 100x magnification, whereas in the 500x magnification there was no difference (P&gt;0,05) between the groups. The evaluation based on SEM images at two magnifications was essential, as it allowed the visualization of grooves and remaining calculi in a comprehensive way at 100x magnification and in more detail at 500x.

Clinical Evaluation of Zirconia and Stainless-Steel crowns in Primary Molars - A Randomized Control Trial

Background and Aim: Aesthetic alternatives to stainless steel crown for restoring primary molars attain a growing interest. The aim of the study was clinical evaluation and comparison of zirconia and stainless steel crown in primary molars (clinical and radiograph) Methods: A randomized controlled study was conducted on children of age group of 5 to 8 years of age visiting, KVG Dental College and Hospital, Sullia and who were meet the inclusion criteria of the study. The study population was randomly divided into two groups of 24 each. Group I: stainless steel crown, Group II: zirconia crown. Post endodontic tooth preparation was done and selected stainless steel and zirconia crowns followed by cemented using type 1 glass ionomer cement. The subjects was be recalled after 3, 6 and 9 months to check gingival index, oral hygiene index and bone health of the tooth using intraoral periapical radiograph. Results: There was significant increase in score of gingival index and OHI score for both SSC and zirconia crowns after 3 month followed by reduction in score at 6 and 9 months. There was no statistically significant difference in alveolar bone height in both groups (zirconia and SSCs) for 6 months. Conclusion: Zirconia crowns presented to be an excellent choice for primary posterior teeth full coverage restorations. Zirconia crowns performed better than SSCs in the aspect of gingival response and prevention of plaque adhesion. Keywords: zirconia crowns, stainless steel crown, primary molars, esthetics, dental caries.

Mussels Fabricate Porous Glues via Multiphase Liquid-Liquid Phase Separation of Multiprotein Condensates.

Mussels (Mytilus edulis) adhere to hard surfaces in intertidal marine habitats with a porous underwater glue called the byssus plaque. The plaque is an established role model for bioinspired underwater glues and comprises at least six proteins, most of which are highly cationic and enriched in the post-translationally modified amino acid 3,4-dihydroxyphenylalanine (DOPA). While much is known about the chemistry of plaque adhesion, less is understood about the natural plaque formation process. Here, we investigated plaque structure and formation using 3D electron microscopic imaging, revealing that micro- and nanopores form spontaneously during secretion of protein-filled secretory vesicles. To better understand this process, we developed a method to purify intact secretory vesicles for in vitro assembly studies. We discovered that each vesicle contains a sulfate-associated fluid condensate consisting of ∼9 histidine- and/or DOPA-rich proteins, which are presumably the required ingredients for building a plaque. Rupturing vesicles under specific buffering conditions relevant for natural assembly led to controlled multiphase liquid-liquid phase separation (LLPS) of different proteins, resulting in formation of a continuous phase with coexisting droplets. Rapid coarsening of the droplet phase was arrested through pH-dependent cross-linking of the continuous phase, producing native-like solid porous "microplaques" with droplet proteins remaining as fluid condensates within the pores. Results indicate that histidine deprotonation and sulfates figure prominently in condensate cross-linking. Distilled concepts suggest that combining phase separation with tunable cross-linking kinetics could be effective for microfabricating hierarchically porous materials via self-assembly.

Comparative Evaluation of Surface Roughness and Wettability of an Alkasite with Nano Bulk-Fill and Nanofilled Resin Composite Restorative Materials: In vitro Study.

Surface characteristics of resin-based composites (RBCs) can change with polishing and over time. The aim of the study was to compare the surface roughness and wettability of three different posterior RBCs after polishing and the change in these surface characteristics over time, after aqueous aging. Experimental in vitro study. Eleven disc-shaped RBC specimens were fabricated. The RBCs used were, alkasite composite, bulk-fill nanocomposite, conventional nanofilled composite. All the specimens underwent polishing with Soflex Diamond Polishing System and then analyzed for roughness and wettability at baseline and after aqueous aging for 3 months with the help of an atomic force microscope and a contact angle goniometer respectively. One-way ANOVA and Tamhane test were used for the multiple comparisons. Alkasite composite showed significantly higher surface roughness (P = 0.028 and P < 0.001, respectively) and lower wettability (P = 0.023 and P = 0.020, respectively) than conventional nanofilled composite at baseline and 3 months. Surface roughness of alkasite composite was also significantly higher than bulk-fill nanocomposite (P = 0.009 and P < 0.001, respectively) at both the time points. Alkasite has higher surface roughness in comparison to conventional nanocomposite and bulk-fill nanocomposite and lower wettability than conventional nanocomposite after polishing and aqueous aging over a 3-month period. In terms of surface characteristics, alkasite composite may be advantageous in preventing initial plaque adhesion to the material surface, but the lower surface roughness of nano-filled composites may be more advantageous in terms of plaque retention prevention.

The mechanism of Megalobrama amblycephala muscle injury repair based on RNA-seq

Skeletal muscle myogenesis and injury-induced muscle regeneration contribute to muscle formation. Skeletal muscle stem cells, termed satellite cells (SCs), proliferate to repair injured muscle. To identify the molecular mechanism of regeneration after muscle injury as well as the genes related to muscle development in fish, in this study, the immunohistochemistry and the high-throughput RNA sequencing (RNA-seq) analysis were performed after Megalobrama amblycephala muscle was injured by needle stab. The results showed that paired box7-positive (Pax7+) SCs increased, and peaked at 96 to 144h-post injury (hpi). The 6729 differentially expressed genes (DEGs), including 2125 up-regulated and 4604 down-regulated genes were found. GO terms significantly enriched by DEGs contained intercellular connections, signaling transduction and enzyme activity. KEGG enrichment analysis showed that most of the pathways were related to immunity, metabolism and cells related molecules, including actin skeleton regulation, Epstein Barr virus infection and plaque adhesion. The WGCNA results revealed that actin cytoskeleton and lipid metabolism related genes probably played crucial roles during repair after muscle injury. Collectively, all these results will provide new insights into the molecular mechanisms underlying muscle injury repair of fish.

Biofilm and Orthodontic Materials: literature reviews and Scanning Electron Microscopy (SEM) images gallery

Plaque control remains a concern in oral health but also in orthodontics. The aim of this paper was to investigate the dental plaque adhesion to different orthodontic appliances. Four literature reviews were initiated to clarify the accumulation of dental plaque to different orthodontic appliances, namely the type of brackets (conventional versus self-ligating, metal versus clear), the type of ligatures (metal versus elastomeric) in addition to the type of archwires. Moreover, a gallery of Scanning Electron Microscopy (SEM) images was made on different orthodontic appliances before and/or after time in the oral cavity. Considering the strong methodological heterogeneity of the included studies, there is no consensus on which type of bracket should be preferred for the prevention of plaque retention. Metal ligatures would be less prone to plaque accumulation compared to elastomeric ligatures, which are themselves color-dependent. The type of archwire was not investigated in this topic. SEM images highlighted the presence of anfractuosities on the surface of new orthodontic archwires as well as the presence of biofilm at different degrees of maturation on the appliances after time in the oral cavity. Although it is not possible to establish a consensus on which orthodontic appliances should be preferred to decrease plaque retention, different stages of biofilm evolution are observable on their surface and therefore potentially associated with a proportional virulence.

Effect of immediate and delayed finishing and polishing procedure on Streptococcal mutans adhesion and micro-hardness of composite resin surface: An in-vitro study

Proper finishing and polishing have become the indispensable step in clinical restorative dentistry due to increased aesthetic demands. There are several polishing systems containing fine particle size abrasives. The adhesion of bacterial plaque to restoration depends on the surface properties and composition of materials. In literature, surface roughness after polishing is well documented, but the timing, i.e., immediate or delayed polishing affecting the bacterial adherence and microhardness on the composite needs research. As the Streptococcus mutans has a major role in primary and secondary caries, so in this light, this study is conducted to investigate the best timing of polishing affecting the bacterial adhesion and microhardness of composite resin.: To evaluate the Streptococcal mutans adhesion and microhardness of composite resin after polishing them, immediately and after 24 hours of curing.: Sixty specimens were made from composite resin Filtek Z 350 XT (3M ESPE) of 6mm diameter and 4mm height, was cured by placing a Mylar strip and divided into 3 groups- Group 1 the control group with only MYLAR-STRIP, Group 2- Polishing system SOF-LEX (3M ESPE Dental products St. Paul, MN,USA.) Group 3- Polishing with SUPER-SNAP (Shofu Inc., Kyoto, Japan). Group 2 and 3 were further divided into two subgroups according to the polishing time- immediate and delayed. The Streptococcal mutans adhesion for each group was measured by colony forming units and compared. The mean log of CFU/mL present in the biofilm was also calculated. The results of bacterial adherence was analysed by three-way ANOVA (analysis of variance) (p&amp;#60;0.01) and the ANOVA two-way of variance was used for checking microhardness (p&amp;#60;0.01). A p value &amp;#60;0.01 was considered to indicate a statistically significant for both bacterial adhesion and hardness. Polishing after 24 hours of curing showed less bacterial adherence on the composite surface, regardless of the polishing treatment performed(p&amp;#60;0.01). Polishing with SOF-LEX(Group-2) had the lower bacterial adherence than SUPER-SNAP (Group-3), Control group (Mylar matrix strip) promoted the lowest bacterial adhesion on the surface composites. Micro hardness of composite was lowest in Mylar matrix group. Immediate polishing procedure showed lower microhardness values as compared to polishing that was delayed for 24hours for both polishing groups. SOF-LEX system can be used for chairside polishing of composite restorations in clinic and delayed finishing and polishing of composite shows better surface microhardness values.

A Study of Plaque Adhesion during Implant Treatment of Missing Molars

Purpose: In implant treatment, the abutments and superstructures form a transmucosal area. In addition to providing appropriate cleaning instructions to patients, its material properties must be carefully considered. It is not clear how much plaque adhesion occurs at each site during treatment process, and the effect of materials on plaque adhesion. Methods: In this study, 33 patients, 13 maxillary cases and 20 mandibular cases, who had implants placed in the missing molars were evaluated for the plaque adhesion of provisional restorations made of acrylic resin and monolithic zirconia final restoration after a period of more than 4 weeks. In addition, oral hygiene instructions were thoroughly given for 12 cases at the time of staining after the provisional restorations, and re-evaluated in 4 weeks. Results: About 20% of the buccal-lingual area of the prosthetic device fabricated with acrylic resin showed plaque staining, whereas about 40% of the area of the mesial and distal. On the other hand, for the zirconia final restorations, the percentage of staining was about 5% for buccal and lingual surface and 10% for mesial and distal surface. The stained area ratio of the provisional restoration correlated with the zirconia superstructure area ratio. Even with careful oral hygiene, it became clear that the amount of plaque adhesion due to the difference in materials could not be overcome. Conclusion: The zirconia superstructure is extremely good from the viewpoint of plaque adhesion, but cases with a large stained area at the time of provisional restoration should be carefully followed up.

Three-year survey of oral hygiene conditions of Cambodian public primary school children.

The purpose of this repeated cross-sectional study was to investigate the prevalence and severity of oral hygiene conditions in Cambodian primary school children. Oral examinations were conducted on 2,020 school children (1st-6th grade) at a public primary school in Siem Reap, Cambodia from 2013 to 2015, focusing on plaque adhesion, gingiva, and dental calculus deposition. Data analysis was performed on 1,998 children without any missing data, and the chi-square test was used to compare the variables. The prevalence of dental plaque adhesion in 2013, 2014, and 2015 was 93.6%, 93.7%, and 85.1%, respectively. The prevalence of gingivitis in 2013, 2014, and 2015 was 93.1%, 92.1%, and 88.8%, respectively. The prevalence of dental calculus deposition in 2013, 2014, and 2015 was 55.1%, 19.3%, and 34.7%, respectively. Significant differences were observed in all variables each year (P < 0.001). The findings of this study suggest that oral hygiene conditions were poor in this population.