Effect of Antimicrobial Agent Coating on Physicochemical and Biologic Properties of Implant Abutments: A Systematic Review

PURPOSE

To analyze the effectiveness of coating of abutments with antimicrobial agents and their influence on the physicochemical and biologic properties of the coated materials.

MATERIALS AND METHODS

This work was registered in Open Science Framework (osf.io/6tkcp) and followed the PRISMA protocols. A search of two independent reviewers of articles published up to October 29, 2021, was performed in the Embase, PubMed, Science Direct, and Scopus databases.

RESULTS

The databases found a total of 1,474 references. After excluding the duplicates, 1,050 remained. After reading the titles and abstracts and applying the inclusion criteria, 13 articles remained and were read in full. A total of 8 articles were included in this systematic review. Different antimicrobial agents have been used to coat abutments, including graphene oxide, polydopamine, titanium and zirconium nitride, lactoferrin, tetracycline, silver, and doxycycline with varied release times. Titanium-coated silver showed a better antimicrobial agent release time of up to 28 days. Chemical analysis confirmed the presence of antimicrobials on the surface after coating. Different pathogenic microorganisms, such as Streptococcus sanguinis, Streptococcus oralis, and Staphylococcus aureus, were inhibited when in contact with the coated surface.

CONCLUSIONS

This review showed that there is still no consensus on which is the better antimicrobial agent and which coated materials have the better performance. However, the association of surface coating of abutments with antimicrobials is feasible and can benefit many patients, which can support their clinical use to favor the healing process and prevent infections that can lead to treatment failure with dental implants.

Silver vanadate nanomaterial incorporated into heat-cured resin and coating in printed resin - Antimicrobial activity in two multi-species biofilms and wettability

OBJECTIVES

To incorporate the nanostructured silver vanadate decorated with silver nanoparticles (AgVO3) into denture base materials: heat-cured (HC) and 3D printed (3DP) resins, at concentrations of 2.5 %, 5 %, and 10 %; and to evaluate the antimicrobial activity in two multi-species biofilm: (1) Candida albicans, Candida glabrata, and Streptococcus mutans, (2) Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus, and the wettability.

METHODS

The AgVO3 was added to the HC powder, and printed samples were coated with 3DP with AgVO3 incorporated. After biofilm formation, the antimicrobial activity was evaluated by colony forming units per milliliter (CFU/mL), metabolic activity, and epifluorescence microscopy. Wettability was assessed by the contact angles with water and artificial saliva.

RESULTS

In biofilm (1), HC-5 % and HC-10 % showed activity against S. mutans, HC-10 % against C. glabrata, and HC-10 % and 3DP-10 % had higher CFU/mL of C. albicans. 3DP-5 % had lower metabolic activity than the 3DP control. In biofilm (2), HC-10 % reduced S. aureus and P. aeruginosa, and HC-5 %, 3DP-2.5 %, and 3DP-5 % reduced S. aureus. 3DP incorporated with AgVO3, HC-5 %, and HC-10 % reduced biofilm (2) metabolic activity. 3DP-5 % and 3DP-10 % increased wettability with water and saliva.

CONCLUSION

HC-10 % was effective against C. glabrata, S. mutans, P. aeruginosa, and S. aureus, and HC-5 % reduced S. mutans and S. aureus. For 3DP, 2.5 % and 5 % reduced S. aureus. The incorporation of AgVO3 into both resins reduced the metabolic activity of biofilms but had no effect on C. albicans. The wettability of the 3DP with water and saliva increased with the addition of AgVO3.

CLINICAL SIGNIFICANCE

The incorporation of silver vanadate into the denture base materials provides antimicrobial efficacy and can prevent the aggravation of oral and systemic diseases. The incorporation of nanomaterials into printed resins is challenging and the coating is an alternative to obtain the inner denture base with antimicrobial effect.

Comparative analysis of the physical, chemical, and microbiological properties of Ti-6Al-4V disks produced by different methods and subjected to surface treatments

STATEMENT OF PROBLEM

To improve the osseointegration of dental implants and reduce microbiological growth, different micro- and nanoscale surface topographies can be used.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of Ti-6Al-4V with 4 surfaces, machined (DU), machined+hydroxyapatite (DUHAp), machined+acid-alkali treatment (DUAA), and additive manufacturing (DMA), on the physical, chemical, and microbiological properties.

MATERIAL AND METHODS

The topography of Ti-6Al-4V disks with the 4 surfaces was evaluated by scanning electron microscopy (SEM), the chemical composition by energy dispersive X-ray spectroscopy (EDS), and the crystalline structure by X-ray diffraction (XRD). Physical and chemical properties were analyzed by using wettability and surface free energy, roughness, and microbial adhesion against Staphylococcus aureus by colony forming units (CFU). One-way ANOVA analysis of variance and the Tukey multiple comparisons test were applied to evaluate the data, except CFU, which was submitted to the Kruskal-Wallis nonparametric test (α=.05).

RESULTS

DU photomicrographs showed a topography characteristic of a polished machined surface, DUHAp and DUAA exhibited patterns corresponding to the surface modifications performed, and in DMA the presence of partially fused spherical particles was observed. The EDS identified chemical elements inherent in the Ti-6Al-4V, and the DUHAp and DUAA disks also had the ions from the treatments applied. XRD patterns revealed similarities between DU and DMA, as well as characteristic peaks of hydroxyapatite (HA) in the DUHAp disk and the DUAA. Compared with DU and DMA the DUHAp and DUAA groups showed hydrophilic behavior with smaller contact angles and higher surface free energy (P<.05). DMA showed a higher mean value of roughness, different from the others (P<.05), and a higher CFU for S. aureus (P=.006).

CONCLUSIONS

DUHAp and DUAA showed similar behaviors regarding wettability, surface free energy, and bacterial adhesion. Among the untreated groups, DMA exhibited higher roughness, bacterial adhesion, and lower wettability and surface free energy.

Protein absorption on titanium surfaces treated with a high-power laser: A systematic review

STATEMENT OF PROBLEM

The surface of titanium dental implants treated with a high-power laser has been reported to favor osseointegration, mainly by altering protein uptake. Despite the large number of articles that address the topic, the heterogeneity of methodologies and results makes an understanding of the treatment's benefits difficult, and a systematic review is needed.

PURPOSE

The purpose of this systematic review was to further the knowledge on protein uptake on titanium surfaces that have undergone treatment with a high-power laser.

MATERIAL AND METHODS

This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and was registered with the Open Science Framework (OSF) (osf.io/gcbna). Searches were performed in PubMed, Scopus, Web of Science, Embase, and Google Scholar databases. The articles were selected in 2 steps by 2 independent reviewers according to the previously selected eligibility criteria. The risk of bias was analyzed by using the Joanna Briggs Institute (JBI)-adapted quasi-experimental study evaluation tool.

RESULTS

The studies addressed have shown that applying a high-power laser to the implant surface, depending on its settings, generates topographical changes that can optimize the protein absorption process and thus accelerate the other biological processes.

CONCLUSIONS

The studies identified in this systematic review showed that surface treatment with a high-power laser represents a promising technique with a positive influence on protein uptake and osseointegration.

Relationship between dental implant macro-design and osseointegration: a systematic review

PURPOSE

This systematic review aimed to determine whether differences in the macro-geometry of titanium implants promote changes in osseointegration.

MATERIAL AND METHOD

SCOPUS, PubMed/Medline, Web of Science, and EMBASE databases were searched in June 2021. In addition, it was performed a manual search of the reference lists of the included articles. Eligibility criteria were in vivo studies that addressed the effect of titanium implant macro-geometry on osseointegration, studies that evaluated periodontally healthy models, and papers indexed in Journal Citation Reports.

RESULTS

The database search resulted in 1037 articles. Of the 19 articles selected for full reading, 16 remained in this systematic review. These had a high heterogeneity making it hard to perform statistical analysis of the data, so a descriptive analysis was performed.

CONCLUSIONS

Based on the studies included in this systematic review, implant macro-geometry provides influences on osseointegration. In this sense, the various isolated characteristics (thread type, thread pitch, thread depth, face angle) should be studied so that the implant geometry can balance the compressive stress and tensile stress and produce a minimum shear force.

Assessment of neuromuscular fatigue through frequency analysis of the electromyographic signal of control participants and those with temporomandibular dysfunction treated with resilient or hard occlusal devices

STATEMENT OF PROBLEM

Muscle hyperactivity that leads to neuromuscular fatigue can be evaluated by electromyography. Whether treatment with occlusal devices can restore neuromuscular balance to patients with temporomandibular disorders (TMDs) is unclear.

PURPOSE

The purpose of this clinical study was to evaluate neuromuscular fatigue by analyzing the frequency of the electromyographic signal of the masseter and anterior temporalis muscles on both sides in healthy participants and those with TMD treated with a resilient or hard occlusal device.

MATERIAL AND METHODS

One hundred asymptomatic participants and 30 with TMD were divided into 2 groups: treated with a hard device or treated with a resilient device. All underwent electromyographic examination before and after treatment with the occlusal devices.

RESULTS

In both groups, the results showed statistically significant differences (P<.01) when the fatigue rate before and after treatment with an occlusal device was compared.

CONCLUSIONS

Treatment with both types of occlusal device was efficient in reducing the rate of neuromuscular fatigue in patients with TMDs.

Antimicrobial activity of essential oils against biofilms formed in dental acrylic resin: a systematic review of in vitro studies

This study aimed to answer the question formulated according to the PICO strategy: 'Which essential oils show antimicrobial activity against biofilms formed on dental acrylic resin?' composed by population (dental acrylic resin), intervention (application of essential oils), comparison (denture cleansers, antifungal drugs, chlorhexidine, and oral mouthwashes), and outcome (antibiofilm activity). In vitro experimental studies evaluating the activity of EOs on biofilm formed on acrylic resin were included. PRISMA guidelines were followed, and the search was performed in the PubMed, Science Direct, Embase, and Lilacs databases and in the gray literature using Google Scholar and ProQuest in December 2023. A manual search of the reference lists of the included primary studies was performed. Of the 1467 articles identified, 37 were selected for full-text reading and 12 were included. Twelve EOs were evaluated, of which 11 showed activity against Candida spp., 3 against Staphylococcus aureus, and 1 against Pseudomonas aeruginosa. The EOs of Cymbopogon citratus, Cinnamomum zeylanicum, and Cymbopogon nardus showed higher action than chlorhexidine, C. nardus higher than Listerine, C. citratus higher than nystatin, and Melaleuca alternifolia higher than fluconazole and nystatin. However, chlorhexidine was more effective than Lippia sidoides and Salvia officinalis, sodium hypochlorite was more effective than L. sidoides, nystatin was more effective than Zingiber officinale, Amphotericin B more effective than Eucalyptus globulus and M. alternifolia. In conclusion, the EOs of C. zeylanicum, C. citratus, C. nardus, and M. alternifolia showed antimicrobial activity to reduce biofilm on dental acrylic resin.

Mechanical and microbiological properties of orthodontic resin modified with nanostructured silver vanadate decorated with silver nanoparticles (βAgVO3)

OBJECTIVE

To investigate the impact of incorporating the antimicrobial nanomaterial β-AgVO3 into orthodontic resin, focusing on degree of conversion, surface characteristics, microhardness, adhesion properties, and antimicrobial activity.

METHODS

The 3 M Transbond XT resin underwent modification, resulting in three groups (Control, 2.5% addition, 5% addition) with 20 specimens each. Fourier transform infrared spectroscopy assessed monomer conversion. Laser confocal microscopy examined surface roughness, and microhardness was evaluated using Knoop protocols. Shear strength was measured before and after artificial aging on 36 premolar teeth. Microbiological analysis against S. mutans and S. sanguinis was conducted using the agar diffusion method.

RESULTS

Degree of conversion remained unaffected by time (P = 0.797), concentration (P = 0.438), or their interaction (P = 0.187). The 5% group exhibited the lowest surface roughness, differing significantly from the control group (P = 0.045). Microhardness showed no significant differences between concentrations (P = 0.740). Shear strength was highest in the control group (P < 0.001). No significant differences were observed in the samples with or without thermocycling (P = 0.759). Microbial analysis revealed concentration-dependent variations, with the 5% group exhibiting the largest inhibition halo (P < 0.001).

CONCLUSIONS

Incorporating β-AgVO3 at 2.5% and 5% concentrations led to significant differences in surface roughness, adhesion, and antimicrobial activity. Overall, resin modification positively impacted degree of conversion, surface characteristics, microhardness, and antimicrobial activity. Further research is warranted to determine clinically optimal concentrations that maximize antimicrobial benefits while minimizing adverse effects on adhesion properties.

CLINICAL SIGNIFICANCE

Incorporating β-AgVO3 into orthodontic resin could improve patient quality of life by prolonging intervention durability and reducing the impact of cariogenic microorganisms. The study's findings also hold promise for the industry, paving the way for the development of new materials with antimicrobial properties for potential applications in the health sector.

Denture stomatitis: Treatment with antimicrobial drugs or antifungal gels? A systematic review of clinical trials

STATEMENT OF PROBLEM

Gel formulations containing antimicrobials are a potential alternative for the development of new medicines for the treatment of denture stomatitis (DS). However, whether they are more effective than antifungal drugs is unclear.

PURPOSE

The purpose of this systematic review was to identify whether gels formulated with antimicrobial substances are more effective and biocompatible for the treatment of DS than antifungal drugs.

MATERIAL AND METHODS

This systematic review was structured according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022379510). Searches were performed in the PubMed, Lilacs, Web of Science, Scopus, Embase, and Google Scholar databases in November 2022. Randomized and nonrandomized clinical trials comparing the efficacy of experimental gels and conventional antifungals in the treatment of DS were included.

RESULTS

Gels formulated with Zataria multiflora essential oil and clove and cinnamon extracts showed higher antimicrobial efficacy compared with miconazole and clotrimazole. Formulations containing Uncaria tomentosa, Punica granatum, and propolis extract showed similar efficacy to nystatin and miconazole. Two formulations containing P. granatum were less effective than nystatin and miconazole. Gels of Z. multiflora and miconazole induced adverse effects including burning, itching, nausea, and vomiting. The included studies did not evaluate the biocompatibility of the gels.

CONCLUSIONS

Gels formulated with natural antimicrobials such as Z. multiflora, U. tomentosa, P. granatum, propolis, and clove and cinnamon showed higher or similar antimicrobial efficacy to conventional antifungals in the treatment of DS. The biocompatibility of experimental gels based on natural agents should be evaluated.

Influence of 3D-Printing Parameters and Characteristics of Complete Denture Bases on Evaluated Properties: A Scoping Review

PURPOSE

To verify the parameters and characteristics evaluated in 3D-printed complete denture (CD) bases and how they influence CD properties.

MATERIALS AND METHODS

This work was registered in Open Science Framework (osf.io/4um6v) and followed the PRISMA Extension for Scoping Reviews. A search of peer-reviewed articles published up to April 9, 2020, was performed on the PubMed, LILACS, Cochrane Library, and Science Direct databases. The review question based on the PCC (population, concept, and context) was: What printing parameters and characteristics of CD bases can influence their properties?

RESULTS

The database search resulted in 1,945 articles, and the initial screening was carried out in 1,390 articles, 17 of which were selected for inclusion in this review. The present authors verified that cleaning the prosthesis with alcohol after printing followed by a postcuring cycle influences biocompatibility and residual monomers. The printing angle influences physicomechanical properties, microbial adhesion, and tissue adaptation. Accuracy is influenced by layer thickness and manufacturing technique, which also influences retention and tissue adaptation. The incorporation of antimicrobial agents influences physicomechanical properties and antimicrobial activity. The method of union between the denture base and teeth influences mechanical strength.

CONCLUSIONS

Printed denture bases showed good adaptation to tissues and accuracy with 100-µm layer thickness, but the base must be cleaned in ethanol followed by postcuring for better biocompatibility. Nano- and microparticles can be added to provide antimicrobial activity and better resistance. The printing angle and mechanical properties must be better evaluated. Int J Prosthodont 2023;36:620-629.

An In Vitro Analysis of the Physical and Mechanical Behavior of a PEEK Component for an Implant-Supported and Retained Removable Dental Prosthesis

PURPOSE

To investigate the physical and mechanical behaviors of polyether ether ketone (PEEK) before and after thermocycling, as well as its potential use as a more durable prosthetic component for implant-supported and -retained removable dental prostheses (I-RDPs).

MATERIALS AND METHODS

Roughness and surface hardness were evaluated in specimens obtained using the subtractive method (n = 20) with a diameter of 9 mm and a thickness of 2 mm, and retention force was measured using attachments with a diameter of 4 mm and a height of 3 mm. For fatigue resistance testing, a polyurethane matrix with two ball abutment implants (MDL, Intra-Lock International) was used to simulate the mandibular alveolar ridge. A total of 40 attachments (n = 20 pairs) were placed in acrylic resin blocks using an analog technique for the direct clinical pickup of overdenture female attachments, then submitted to 2,900 insertion/removal cycles to simulate 24 months of overdenture use. Physical analyses were performed by Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and differential scanning calorimetry (DSC) before and after thermocycling (5°C to 55°C for 10,000 cycles). After normal distribution was verified by Shapiro-Wilk test, one-way ANOVA was applied to analyze the surface roughness and hardness, and two-way ANOVA with Bonferroni adjustment was used to assess the retention force (α = .05).

RESULTS

Thermocycling did not change the PEEK surface roughness or hardness (P > .05). As for the retention force, the highest average was observed after the thermocycling test (P = .006).

CONCLUSION

Based on the FTIR, XRD, and DSC results, PEEK crystallinity decreased after thermocycling, and the physical and mechanical behaviors of this polymer were compatible with the proposed application, suggesting that PEEK is a component of greater durability for I-RDPs. Int J Prosthodont 2023;36:612-619.

Hydroxyapatite coatings versus osseointegration in dental implants: A systematic review

STATEMENT OF PROBLEM

Knowledge of the effectiveness of hydroxyapatite coatings on the surface of titanium dental implants is lacking because of difficulties in standardizing their thickness, roughness, and effect on osseointegration. The selection of articles describing this coating in osseointegration will be of great relevance to implant dentistry.

PURPOSE

This systematic review aimed to answer the question, "How effective is hydroxyapatite on titanium surfaces for osseointegration?"

MATERIAL AND METHODS

The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines were followed, and the protocol was registered on the international prospective register of systematic reviews (PROSPERO) database (CRD42023422601). The PubMed, Scopus, Web of Science, and Embase databases were searched, and articles were selected manually in 2 steps by 2 blinded investigators according to the previously selected eligibility criteria. The risk of bias was assessed using the systematic review center for laboratory animal experimentation (SYRCLE) tool.

RESULTS

Initially, 671 results were found. After analysis of eligibility criteria and full reading, 15 articles were included in the present review. Of these, 12 reported favorable osseointegration results for hydroxyapatite-coated surfaces, and 3 found no significant long-term difference between the coated and uncoated groups.

CONCLUSIONS

Hydroxyapatite surface treatment is effective in the osseointegration of titanium dental implants because it favors the absorption of proteins, adhesion, and proliferation of bone cells when obtained by methods that ensure proper adhesion. (J Prosthet Dent xxxx;xxx:xxx-xxx).

Influence of dental implant/mini-implant design on stress distribution in overdentures: a systematic review

PURPOSE

Critically evaluate the existing literature and answer the question, "Does the dental implant/mini-implant design influence the stress distribution in prosthetic overdentures according to finite element analysis?".

METHODS

This systematic review was registered in the Open Science Framework (osf.io/2bquj) and followed the PRISMA protocols. The custom search strategy was applied to 4 databases. In vitro experimental studies that evaluated the influence of dental implant/mini-implant design on stress distribution in overdentures by FEM, without time and language restrictions, were included. The selection process was carried out in two stages by two reviewers independently. Risk of bias analysis was performed by a checklist of important parameters.

RESULTS

Sixty articles were evaluated by their title and abstract, four were selected for full reading, three were relevant, and nine were included by additional search. The 12 studies have a low risk of bias. The meta-analysis could not be performed due to the heterogeneity of the data (implant type, design variation, load intensity, and direction).

CONCLUSION

It can be inferred from the evaluated literature that design modifications influence the stress distribution, but as the FEM presents limitations inherent to the in vitro study, clinical trials are necessary to infer the effectiveness of the modifications. It should be noted that there is no consensus on which is the best thread design and that implants with a very narrow diameter are subject to the highest stress concentration.

Effect of pores on cell adhesion to additively manufactured titanium implants: A systematic review

STATEMENT OF PROBLEM

Titanium dental implants produced by additive manufacturing have pores that, depending on their size and quantity, may improve osteogenic cell adhesion without impairing mechanical properties. A systematic review of in vitro studies on this topic is lacking.

PURPOSE

The purpose of this systematic review was to answer the question "What is the influence of pores on osteogenic cell adhesion on titanium surfaces produced by additive manufacturing?".

MATERIAL AND METHODS

The study was designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 standards and registered in the Open Science Framework (OSF) (osf.io/baw59). A manual search of published articles without language or time restrictions was conducted in November 2022 in the electronic databases PubMed, Scopus, ScienceDirect, Embase, and in the nonpeer-reviewed literature via Google Scholar.

RESULTS

A total of 1338 initial results were found, and after removing duplicates and applying eligibility criteria, 13 articles were included in this review that, according to the Joanna Briggs Institute (JBI) tool, presented a low risk of bias. Pores with larger diameters provide greater a surface area that favors cell filopodia adhesion and has interconnection that optimizes the transport of nutrients and oxygen and bone cell activity.

CONCLUSIONS

The presence of pores on the surface of titanium produced by additive manufacturing increases the adhesion, migration, proliferation, and viability of osteogenic cells.

Bacterial Adhesion Strength on Titanium Surfaces Quantified by Atomic Force Microscopy: A Systematic Review

Few studies have been able to elucidate the correlation of factors determining the strength of interaction between bacterial cells and substrate at the molecular level. The aim was to answer the following question: What biophysical factors should be considered when analyzing the bacterial adhesion strength on titanium surfaces and its alloys for implants quantified by atomic force microscopy? This review followed PRISMA. The search strategy was applied in four databases. The selection process was carried out in two stages. The risk of bias was analyzed. One thousand four hundred sixty-three articles were found. After removing the duplicates, 1126 were screened by title and abstract, of which 57 were selected for full reading and 5 were included; 3 had a low risk of bias and 2 moderated risks of bias. (1) The current literature shows the preference of bacteria to adhere to surfaces of the same hydrophilicity. However, this fact was contradicted by this systematic review, which demonstrated that hydrophobic bacteria developed hydrogen bonds and adhered to hydrophilic surfaces; (2) the application of surface treatments that induce the reduction of areas favorable for bacterial adhesion interfere more in the formation of biofilm than surface roughness; and (3) bacterial colonization should be evaluated in time-dependent studies as they develop adaptation mechanisms, related to time, which are obscure in this review.

Analysis of stress/strain distribution in dental mini-implants manufactured by additive manufacturing and machining

The study aimed to analyze the stress/strain distribution of new designs of mini-implants manufactured by machining and additive manufacturing. Four designs were evaluated (Ø2.0 mm × 10 mm): Intra-lock, helical, threaded machined (MN threaded) and threaded by additive manufacturing (AM threaded). Analysis of stress was performed through photoelastic analysis (100 N axial/oblique loads) and analysis of strain by digital image correlation (DIC) (250 N axial/100 N oblique load). Data distribution was verified using the Shapiro-Wilk test and a significance level of 5% was adopted. Quantitative data were analyzed using the non-parametric Kruskal-Wallis test. In photoelastic analysis, the Intra-lock mini-implant showed the highest stresses in the cervical (104 kPa), middle (108 kPa), and apical (212 kPa) thirds. Higher stresses were observed in the oblique loading situation for all designs. For DIC analysis, axial loading, a significant difference was observed for the AM Threaded mini-implants about the other designs in the cervical third (p = .04), with the highest strain value 47 με [10; 76]. In oblique loading, a significant difference between the mini-implants was observed in the middle and apical thirds, with higher strains for the AM threaded design -185 με [-173; 162] (p = .009) and 242 με [87; 372] (p = .013), respectively. In general, the influence of different mini-implant designs and the additive manufacturing method on the stress/strain was observed, in the photoelastic and DIC analysis. The evaluated designs demonstrated a lower concentration of stress/strain in the cervical region compared to the apical region, and higher stress/strain in situations of oblique load compared with axial load.

Osseointegration in relation to drilling speed in the preparation of dental implants sites: A systematic review

STATEMENT OF PROBLEM

The drilling speed used for preparing dental implants may affect bone-implant contact (BIC), implant stability quotient (ISQ), and bone area fraction occupancy (BAFO). Different rotational speeds and the presence or absence of irrigation during site preparation have been investigated, but an established protocol for achieving the best osseointegration results is lacking.

PURPOSE

The purpose of this systematic review was to investigate the influence of drill rotational speed on bone drilling for dental implant placement and its relationship with osseointegration.

MATERIAL AND METHODS

This review included the preferred reporting items for systematic reviews and meta-analyses (PRISMA) and was registered in the international prospective register of systematic reviews (PROSPERO) database. Electronic searches were performed in the MEDLINE (PubMed), Scopus, Science Direct, and Embase databases. The risk of bias was analyzed by using the systematic review center for laboratory animal experimentation (SYRCLE).

RESULTS

A total of 1282 articles were found, and after removing duplicates and applying the eligibility criteria to in vivo articles on animals that addressed drilling speed and its relationship to osseointegration, 8 articles were selected for analysis. Of these, 5 articles showed no statistical differences, and 3 others showed significantly better osseointegration results by analyzing the parameters of BIC, BAFO, ISQs, and pull-out forces (PoFs). In all selected articles, high-speed drilling was performed with irrigation.

CONCLUSIONS

Although drilling speed seems to affect bone perforation, no definitive protocol was found in the literature consulted. The results vary depending on the combination of different factors, including bone type, irrigation, and drilling speed.

Reasons for the fatigue of ball attachments and their O-rings: A systematic review

The ball attachments and their O-rings used for the retention and stabilization of overdentures showed a decrease in retention as the number of cycles increased. This fact resulted in a decrease in the retention of the prosthesis. The purpose of this study was to evaluate the fatigue resistance of ball attachments through a systematic review. An electronic search was performed using the Cochrane Library, LILACS, PubMed, ScienceDirect, and Web of Science databases. The search was conducted based on the PICOS framework. The inclusion criteria involved in the search comprised research articles written in English and published between the years 2000 and 2020. In the final selection, 18 articles were included in the review. Most of these studies performed the fatigue retention tests using parallel implants without angles. However, some studies used different angles to analyze the fatigue retention values. With the passage of time, the wear results in deformation and, as a consequence, a decrease in the retention of most attachments, leading to treatment failure. The main factor to be considered is the loss of retention of these components and their low durability. The loss of retention is due to large extent to the materials used to manufacture the attachments and O-rings, the size and angulation of the implants, and the length of the prosthesis. Future research is needed to further elucidate the reasons for the failure of the attachments.

Influence of antibacterial surface treatment on dental implants on cell viability: A systematic review

There is no consensus in the literature about the best non-cytotoxic antibacterial surface treatment for dental implants. Critically evaluate the existing literature and answer the question: "which surface treatment for dental implants made of titanium and its alloys has the greatest non-cytotoxic antibacterial activity for osteoblastic cells?" This systematic review was registered in the Open Science Framework (osf.io/8fq6p) and followed the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols. The search strategy was applied to four databases. Articles were selected that evaluated in both studies the properties of 1) antibacterial activity and 2) cytotoxicity on osteoblastic cells of titanium and their alloy dental implants when treated superficially. Systematic reviews, book chapters, observational studies, case reports, articles that studied non-dental implants, and articles that evaluated only the development of surface treatment were excluded. The Joanna Briggs Institute, a quasi-experimental study assessment tool, was adapted to assess the risk of bias. The search strategy found 1178 articles in the databases after removing duplicates in EndNote Web, resulting in 1011 articles to be evaluated by title and abstract, of which 21 were selected for full reading, of which 12 were included by eligibility criteria, and nine were excluded. Quantitative synthesis could not be performed due to the heterogeneity of the data (surface treatment, antibacterial assay, bacteria strain, cell viability assay, and cell type). Risk of bias assessment showed that ten studies were classified as low risk and two studies as moderate risk. The evaluated literature allowed us to conclude that: 1) The literature surveyed did not allow answering the question due to the heterogeneity of the studies; 2) Ten of the 12 studies evaluated presented surface treatments with non-cytotoxic antibacterial activity; 3) Adding nanomaterials, QPEI, BG, and CS, reduce the chances of bacterial resistance by controlling their adhesion by electrical forces.

Influence of Er:YAG laser irradiation on surface properties of Ti-6Al-4V machined and hydroxyapatite coated

Surface treatment by laser irradiation can change the topography of titanium; however, little is known about the changes it causes when applied to other coatings. This study aimed to evaluate the influence of Er:YAG laser irradiation on the surface properties of titanium-aluminum-vanadium (Ti-6Al-4V) discs. Four Ti-6Al-4V surfaces were evaluated (n = 10): CON-control, machined without surface treatment; LT-machined + laser treatment; HA-hydroxyapatite coating; and LT-HA-hydroxyapatite coating + laser treatment. For the laser treatment, an Er:YAG laser with a wavelength of 2940 nm, a frequency of 10 Hz, and an energy density of 12.8 J/cm2 was used. The morphology of the coating was investigated by scanning electron microscopy and the surface composition by energy-dispersive X-ray spectroscopy. The influence of laser irradiation treatment on roughness and wettability was also evaluated. The Er:YAG laser promoted a significant reduction in the roughness Sa (p < 0.05) and in the contact angle (p = 0.002) of the LT surface compared to the CON surface. On the LT-HA surface, a significant decrease in roughness was observed only for the Rz parameter (p = 0.015) and an increase in the contact angle (p < 0.001) compared to the HA surface. The use of the Er:YAG laser with the evaluated parameters decreased the surface roughness and improved the wetting capacity of machined without surface treatment. In the group with hydroxyapatite coating, the laser influenced the surface roughness only for the parameter Rz and reduced their wetting capacity.

Mechanical performance of 3-dimensionally printed resins compared with conventional and milled resins for the manufacture of occlusal devices: A systematic review

STATEMENT OF PROBLEM

Digital methods for manufacturing occlusal devices provide advantages over conventional techniques, but information about the mechanical properties of 3-dimensionally (3D) printed resins is scarce.

PURPOSE

The purpose of this systematic review was to evaluate the literature to determine whether 3D-printed resins for occlusal devices present satisfactory mechanical performance when compared with milled and conventional heat polymerized and autopolymerized resins.

MATERIAL AND METHODS

This systematic review followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol and was registered in the Open Science Framework. The search strategy was applied without restriction of time and language to Embase, PubMed, Scopus, Science Direct, and Web of Science databases, and to the nonpeer-reviewed literature in ProQuest and Google Scholar. The selection process was conducted independently in 2 stages by 2 reviewers according to the eligibility criteria. The risk of bias was analyzed by using a checklist of important parameters to be considered. The systematic review considered the population, intervention, comparison, outcome, studies (PICOS) format, where population was resins for 3D printing of occlusal devices, intervention was inherent characteristics of the resin, comparison was conventional heat polymerized, autopolymerized, and milled resins, outcome was mechanical performance, and studies were in vitro experimental studies.

RESULTS

A total of 1430 articles were found with the search strategy. After removing 182 duplicates found in Rayyan, the title and abstract of 1248 articles were evaluated, of which 37 articles were screened from the databases, 23 were selected for full reading, and 6 met the eligibility criteria and were included in this review; 1 had a low risk of bias and 5 had a moderate risk. An additional search of the reference list of included articles did not result in the inclusion of any articles. A quantitative meta-analysis could not be performed because of the heterogeneity of the included studies regarding the type of resin used and the method for evaluating mechanical performance.

CONCLUSIONS

Resins for 3D printing had satisfactory mechanical performance for interocclusal devices when compared with conventional heat polymerized and autopolymerized resins, except for hardness. Milled resins were better than 3D-printed resins in hardness, wear resistance, flexural strength, flexural modulus, and fracture resistance when printing angle and thickness were not considered. Further development is needed in terms of printing techniques and chemical composition, as they are important for optimal mechanical properties and clinical performance.

Association between depression and temporomandibular dysfunction in adults - a systematic review

OBJECTIVE

To critically evaluate the literature and answer the question: "Is there an association between depression and temporomandibular disorder (TMD) in adults?"

METHODS

The personalized search strategy was applied to PubMed, Embase, Web of Science, and Scopus databases. Articles were selected in two stages according to the eligibility criteria. The Joanna Briggs Institute (JBI) tool was used to analyze the risk of bias according to the type of study.

RESULTS

The included articles presented a moderate risk of bias. Based on the studies, individuals with TMD have higher levels of depression compared to the control group. There is also a direct association in that individuals with depression are more susceptible to developing TMD.

CONCLUSION

There is a probable association between depression and TMD in adults. However, more studies with high methodological quality are needed to confirm this finding.

Is there any association between sleep disorder and temporomandibular joint dysfunction in adults? - A systematic review

OBJECTIVE

To answer the question, "Is there any association between sleep disorder and temporomandibular joint dysfunction (TMD) in adults?"

METHODS

This study followed PRISMA guidelines and was registered in PROSPERO. As eligibility criteria, observational studies that evaluated the association between sleep disorder and TMD were included. Exclusion criteria included a) studies that evaluated sleep quality and not the association of sleep disorders with TMD, b) experimental studies, book chapters, conference proceedings, and systematic reviews. The Joanna Briggs Institute tool was used to assess the risk of bias.

RESULTS

In the literature search, 3425 articles were found. After the exclusion of duplicates, 2752 were selected for reading the title and abstract, of which 26 were read in full, and 18 met eligibility criteria.

CONCLUSION

The association of sleep bruxism with TMD is controversial. While, for obstructive sleep apnea, insomnia, snoring, and gastroesophageal reflux, the analyzed studies showed a positive association.

Clinical and In Situ Oral Biofilm Formation on Dental Implant Abutment Materials: A Systematic Review

PURPOSE

This review aimed to summarize the current literature on the oral biofilm formation on alternative abutment materials compared with titanium (Ti) or Ti alloy in clinical and in situ conditions.

MATERIALS AND METHODS

An electronic database search was conducted in PubMed, Cochrane Library, EMBASE, Scopus, Web of Science, LIVIVO, BVS, ProQuest, and OpenGrey up to November 2020. Clinical and in situ studies evaluating the biofilm formed on metallic, ceramic, or polymeric abutment materials compared with Ti or Ti alloy were included. Outcome measures were microbial counts/profile, cell viability, and biofilm coverage/thickness. Clinical parameters were deemed secondary outcomes. Risk of bias was assessed by RoB 2 and ROBINS-I tools.

RESULTS

A total of 10 clinical and 9 in situ studies were included. Meta-analysis was not performed due to heterogeneity across studies. The abutment materials polytetrafluoroethylene, gold alloy, gold-platinum alloy, cobalt-chromium, alumina, and zirconia were reported. Six out of ten clinical studies (60%) and four out of nine in situ studies (44%) found no qualitative or quantitative microbiologic differences between tested materials. When significant differences were detected, conflicting results were reported. Clinical outcomes were consistent with healthy conditions for all investigated materials.

CONCLUSION

There is not enough evidence to support the existence of relevant microbiologic differences in the biofilm formed on alternative abutment materials over Ti and its alloys in oral conditions. No evident relationship between microbiologic results and clinical outcomes were found. In situ studies and polymicrobial analyses showed a higher tendency to find significant differences between materials.

Effect of photobiomodulation treatment on pain control in patients with temporomandibular dysfunction disorder: systematic review

OBJECTIVE

To critically evaluate the literature and answer the question, "How effective is photobiomodulation treatment on pain control in patients with TMJ disorder?".

METHODS

PRISMA, PubMed, Web of Science, Scopus, and Embase databases were used for the personalized search strategy. For risk of bias, Rob 2.0 for randomized clinical trials and ROBINS-I for non-randomized clinical trials were used.

RESULTS

Eighty-four articles were found and, after removing duplicates, seventy one studies were included for titles and abstracts. For a full reading, 30 articles were selected and, according to the eligibility criteria, 24 remained for qualitative analysis. The studies showed a low risk of bias. Due to the heterogeneity of the studies, it was not possible to perform a meta-analysis.

CONCLUSION

Photobiomodulation is an effective adjunct for the treatment of temporomandibular disorders, being a less invasive approach, safe, low-cost, and without side effects.

Influence of β-AgVO3 nanomaterial incorporation on mechanical and microbiological properties of dental porcelain

OBJECTIVE

To explore the effect of adding different percentages of nanostructured silver vanadate decorated with silver nanoparticles (β-AgVO₃) to dental porcelains, evaluating the antimicrobial activity and the influence on the mechanical properties.

METHODS

Thirty-six specimens were made, for each concentration, control group, 0.5%, 1%, 2.5% and 5%, using two commercial brands: IPS InLine and Noritake Cerabien ZR. For the analysis of mechanical properties, the Vickers microhardness test and the roughness test were performed. For the antimicrobial analysis, the XTT and CFU assays were performed.

RESULTS

There was a statistically significant difference between groups for mechanical and microbiological analyses.

SIGNIFICANCE

The modification of dental porcelains, with the incorporation of β-AgVO₃, influenced the mechanical properties of the material and demonstrated antimicrobial activity at certain concentrations.

In vitro assessment of polyetheretherketone for an attachment component for an implant-retained overdenture

STATEMENT OF PROBLEM

Frequent maintenance because of the limited lifetime of overdenture attachments with O-rings has led to the development of materials that might improve their functionality and longevity. However, testing of newly developed attachment materials is lacking.

PURPOSE

The purpose of this in vitro study was to evaluate a newly developed attachment made of polyetheretherketone (PEEK) for an implant-retained overdenture.

MATERIAL AND METHODS

Specimens of PEEK, polyacetal, and Teflon O-ring materials were prepared for analysis of roughness, surface hardness, and compressive strength. For the fatigue resistance test, new specimens based on acrylic resin were subjected to 2880 insertion and removal cycles. Compression and roughness data were compared with the Kruskal-Wallis and Dunn post hoc test; hardness data with ANOVA and t test; and fatigue and stereomicroscopy with ANOVA with repeated measures, t test, and Bonferroni adjustment (α=.05).

RESULTS

Polyacetal had the lowest surface roughness (P=.038). There was a significant difference in hardness among the materials (P<.05). PEEK presented the highest compressive strength among the materials (P<.001). For the fatigue resistance, only polyacetal showed a difference between the initial time-point (P<.05) and subsequent time-points. Polyacetal had a higher fatigue resistance than Teflon (P<.001) and PEEK (P<.05). Regarding the internal deformation of the attachments, a significant difference was observed among the materials (P<.05).

CONCLUSIONS

PEEK showed promising results regarding the physicomechanical properties necessary for use as an overdenture attachment when compared with other evaluated materials. In addition, the PEEK attachment showed results comparable to those in the control group (O-rings) in terms of retention.

Neuroscience contributes to the understanding of the neurobiology of temporomandibular disorders associated with stress and anxiety

OBJECTIVE

This review proposes a neurobiological model for temporomandibular disorders (TMD) associated with stress and anxiety.

METHODS

An electronic search was performed in the PubMed, Embase, and Web of Science databases. Articles published up to 2020 were selected. The search terms were the following: temporomandibular disorders, anxiety, stress, neurobiology of stress and anxiety, and orofacial pain.

RESULTS

In total, there were 100 studies, which presented a total of 10 different analyses. The results were described, demonstrating the type of analysis that was performed on each item analyzed for a better understanding of the context.

CONCLUSION

The conclusion is that the interactions between the masticatory system, temporomandibular joints (TMJs), and stomatognathic apparatus with "stress neuromatrix," "pain neuromatrix," "limbic system," and "neuroimmunoendocrine system" would produce the range of changes observed in neural connectivity and the diversity of symptoms presented in TMD.

Analysis of the influence of surface treatment by high-power laser irradiation on the surface properties of titanium dental implants: A systematic review

STATEMENT OF PROBLEM

High-power laser irradiation may be a promising treatment for titanium dental implant surfaces. However, systematic reviews of the influence of high-power laser irradiation on the different properties of titanium surfaces are lacking.

PURPOSE

The purpose of this systematic review was to analyze the influence of surface treatment by high-power laser irradiation on the surface properties of titanium and its alloys.

MATERIAL AND METHODS

The PubMed, LILACS, COCHRANE library, and Science Direct databases were searched, and articles published in the last 10 years were included. Of the 725 articles initially identified, 27 were selected after full reading and the application of inclusion and exclusion criteria.

RESULTS

The studies evaluated showed that laser irradiation treatment, depending on the settings and parameters used, promoted changes in the surface properties of titanium. In general, lower speed and a higher number of scans increased roughness. Laser surface treatment promoted the inclusion of more oxygen and improved the wetting capacity of titanium. Additionally, laser treatment improved the adherence of coatings.

CONCLUSIONS

Changes in the surface properties of titanium after laser treatment have been demonstrated. However, determining protocols with specific parameters is necessary to optimize the results.

Effect of surface properties of ceramic materials on bacterial adhesion: A systematic review

PURPOSE

The objective of this systematic review was to describe studies that report on whether surface characteristics such as electrostatic charge, surface free energy, and surface topography promote influence on bacterial adhesion on ceramic surfaces.

MATERIAL AND METHOD

Searches in the SCOPUS, PubMed/Medline, Web of Science, EMBASE, and Google Scholar databases were performed between December 2020 and January 2021 and updated in March 2021. In addition, a manual search of reference lists from relevant retrieved articles was performed. The criteria included: studies that evaluated ceramic surfaces, which described factors such as surface free energy, electrostatic charges, roughness, zeta potential, and their relationship with bacteria.

RESULTS

Database search resulted in 348 papers. Of the 24 studies selected for full reading, 17 articles remained in this systematic review. Another five studies were found in references of articles included, totaling 22 studies. These had a high heterogeneity making it difficult to perform statistical analysis, so a descriptive analysis was performed.

CONCLUSIONS

For dental ceramics, not enough results were found to demonstrate the influence of the electrostatic condition, and its relationship with bacterial adhesion. However, studies of this review show that there is a correlation between bacterial adhesion, surface free energy, and topography.

CLINICAL SIGNIFICANCE

The knowledge of ceramics with repulsive physical-chemical interactions would allow an environment suggestive of non-adhesion of pathogenic biofilm.

Effect of Auricular Acupuncture on the Reduction of Symptoms Related to Sleep Disorders, Anxiety and Temporomandibular Disorder (TMD)

BACKGROUND

Auricular acupuncture (AA) is a complementary/integrative therapy, and can be used as adjuvant treatment in sleep disorders, anxiety and the painful symptomatology of temporomandibular disorders (TMDs).

OBJECTIVE

The aim of this investigation was to evaluate the effectiveness of AA in reducing the symptoms of sleep disorders, anxiety and TMDs by applying the Fletcher and Luckett, Beck-BAI and RDC/TMD questionnaires: Axis II, respectively.

DESIGN

This was a nonrandomized clinical trial in which AA was administered to patients between the ages of 20 and 45 years from the School of Dentistry at Ribeirão Preto, São Paolo, Brazil, who had at least one of the following: sleep disorder, anxiety or TMD.

INTERVENTION

Mustard seeds were applied to predetermined auricular acupoints including: Shen Men, neurovegetative system (sympathetic), kidney, anxiety, stomach, maxilla and mandible, liver and stress, once a week for 8 weeks.

OUTCOME MEASURES

To analyze the reduction in sleep disorder symptoms, we used the Fletcher and Luckett questionnaire; for anxiety symptoms, the Beck-BAI questionnaire, and for the degree of chronic TMD pain, the RDC/TMD (Axis II) questionnaire.

RESULTS

Data on sleep, anxiety and TMD disorders were analyzed via Fisher's exact, Wilcoxon and Chi-Square non-parametric tests (α = 0.05), respectively. Reduction in sleep disorder symptoms after the proposed intervention was verified, showed a statistically significant difference (P = .014). There was a reduction in mean anxiety score and a decrease in painful TMD symptoms, but no significant difference (P = .50; P = .947, respectively) before and after AA.

CONCLUSION

In our study, AA was effective in reducing sleep disorder symptoms and our data suggests some relief of symptoms of anxiety and TMD pain.

Digital versus conventional workflow for the fabrication of physical casts for fixed prosthodontics: A systematic review of accuracy

STATEMENT OF PROBLEM

A consensus on the accuracy of additively manufactured casts in comparison with those fabricated by using conventional techniques for fixed dental prostheses is lacking.

PURPOSE

The purpose of this systematic review was to determine the accuracy of additively manufactured casts for tooth- or implant-supported fixed dental prostheses in comparison with that of gypsum casts.

MATERIAL AND METHODS

This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered with the International Prospective Register of Systematic Reviews (PROSPERO) database (CDR42020161006). Eight databases were searched in December 2019 and updated in September 2020. Studies evaluating the dimensional accuracy of additively manufactured casts for fixed dental prostheses in comparison with that of gypsum casts were included. An adapted checklist for reporting in vitro studies (Checklist for Reporting In vitro Studies guidelines) was used to assess the risk of bias.

RESULTS

Eight studies evaluating tooth-supported fixed dental prosthesis casts and 7 studies evaluating implant-supported fixed dental prosthesis casts were eligible for this review. Gypsum casts showed greater accuracy (trueness and precision) in most studies, although additively manufactured casts also yielded highly precise data. One study was associated with a low risk of bias, 9 with a moderate risk of bias, and 5 with a high risk of bias.

CONCLUSIONS

In vitro studies showed that additively manufactured casts and gypsum casts share similar accuracy within the acceptable range for the fabrication of casts. The quality of scanned data, additive manufacture technology, printing settings, and postprocessing procedures plays an essential role in the accuracy of additively manufactured casts. Clinical studies are required to confirm these findings.

Comparison of oral microbiome profile of polymers modified with silver and vanadium base nanomaterial by next-generation sequencing

This study aimed to evaluate two methods of the incorporation of nanostructured silver vanadate decorated with silver nanoparticles (AgVO₃) into acrylic resin and characterize the profile of early and late microbial communities in class and family taxonomic level by pyrosequencing. The specimens were made by adding different concentrations of AgVO₃ (1, 2.5, and 5%) to the heat-activated acrylic resin by two methods: vacuum spatulation (VS) and polymeric film (PF). A control group (0%) without AgVO₃ was also obtained for both methods. After 24 h and 7 days of incubation in human saliva, biofilm samples were collected, DNA was extracted, and 16S rRNA genes were sequenced by the 454-Roche sequencing platform. Seventeen classes and 51 families of bacteria were identified. The abundance of Bacteroidia, Bacilli, Negativicutes, Fusobacteria and Betaproteobacteria classes decreased after 7 days of incubation, and Clostridia, Gammaproteobacteria, and unclassified bacteria increased. The Negativicutes and Betaproteobacteria classes were more abundant when the PF method was used, and Gammaproteobacteria was more abundant when VS was used. The incorporation of 5% AgVO₃ promoted a reduction in the prevalence of Bacilli, Clostridia, Negativicutes, Betaproteobacteria, and unclassified bacteria, and increased Gammaproteobacteria. The addition of AgVO₃ to acrylic resin altered the early and mature microbiome formed on the specimen surface, and the PF method presented a more favorable microbial profile than the VS method.

Effects of photobiomodulation on auriculotherapy points for sleep disorders, anxiety, and temporomandibular dysfunctions

Objective: The purpose of this study was to evaluatephotobiomodulation applied at auriculotherapy points forsleep disorder (SD) and anxiety related to temporomandibulardysfunction (TMD).Methods: The study consisted of two groups of 20 participants: Auriculotherapy group (A) and Control Group(C). The participants responded to the RDC/TMD, Fletcher & Luckett questionnaires, and the Beck Anxiety Inventory to analyze TMD, SD, and anxiety before and after the treatment.Results: The participants presented scores corresponding to mild to moderateanxiety (MDN = 17; CI = [13.16;22.31]) and after treatment, normalor non-existent anxiety (MDN = 9; CI = [8.76; 17.12]) (p = 0.005). There was no significant difference (p > 0.05) between the controland 20 auriculotherapy groups for TMD and SD.Discussion: The results suggest that auriculotherapy was effective in the treatment of anxiety. However, it did not prove effective with the results of the SD and symptoms of TMD.

Comparative analysis of corrosion resistance between beta titanium and Ti-6Al-4V alloys: A systematic review

BACKGROUND

The knowledge of the electrochemical property (corrosion resistance) of beta titanium alloys compared to Ti-6Al-4 V for implants is relevant because of the potential cytotoxic effects that the released ions could cause to long-term health.

OBJECTIVES

The objective of this systematic review was to seek information on the electrochemical properties (corrosion resistance) of beta titanium alloys compared to Ti-6Al-4 V since the awareness of the electrochemical behavior of the implant surface in the medium is essential for the best indication of the alloys or compositional changes, which may promote benefits to bone-implant interaction in all areas that this procedure is required.

METHODS

The PubMed, LILACS, COCHRANE Library, and Science Direct databases were electronically searched for the terms: dental implants AND beta-titanium AND Ti-6Al-4 V AND electrochemical technics. The inclusion criteria were research articles that studied beta-titanium compared to Ti-6Al-4 V using electrochemical techniques in electrolytes of chemical composition similar to body fluid, published in English, between 2000 and 2020. Articles that did not compare the corrosion resistance of these alloys in electrolytes similar to body fluids were excluded.

RESULTS

A total of 189 articles were restored and selected by title and/or abstract according to the inclusion and exclusion criteria, which resulted in 15 articles that were reduced to 8 after read in full. The studies in vitro evaluated the corrosion resistance in electrolytes Hank, Ringer, SBF, and 0.9 % NaCl, between beta titanium alloys, obtained by arc fusion or bars stock, and Ti-6Al-4 V, for dental or biomedical implants submitted to surface treatments by heat treatment, plasma electrolytic oxidation (PEO), alkaline treatment, and thermomechanical.

CONCLUSION

The evaluated literature allowed to determine that 1) The oxides Nb₂O ₅, Ta₂O _5, and ZrO₂ have higher stability and protection quality than that of TiO₂ modified by the oxides of Al and V; 2) A higher modulus of elasticity of the Ti-6Al-4 V alloy favors protection against corrosion by maintaining a thicker and more firmly adhered oxide layer; 3) The increase in the thickness of the Ti alloys superficial layer contributes to the improvement of the corrosion resistance.

Use of Recorded Poetic Audios to Manage Levels of Anxiety and Sleep Disorders

Anxiety and sleep disorders are highly prevalent affecting millions of people worldwide. Complementary therapies like art therapy, bibliotherapy, and music have been used to manage these problems. The objective of this study was to evaluate levels of anxiety and sleep disorder symptoms of participants before and after a 30-day intervention of listening to short poetic audios. Thirty-one participants listened to audio-taped messages, which associate music and literature for 30 days. Questionnaires were answered by participants prior to the start of the study (baseline collection) and after 30 days (final collection). Setting: the study was done in the city of Ribeirao Preto (Sao Paulo-Brazil). Participants were 31 adults with anxiety symptoms and sleep problems. The scores of the questionnaires were analyzed and compared by the t test for paired samples (α = 0.05), used to evaluate possible differences in anxiety and stress symptoms and sleep disturbances before and after the 30 days of intervention. Significantly lower levels of anxiety and sleep disorders were found after the 30-day intervention. This study reinforces the benefits of music and literature for improving the quality of life of people by reducing levels of anxiety and sleep disorder symptoms.

Influence of the electrostatic condition of the titanium surface on bacterial adhesion: A systematic review

STATEMENT OF PROBLEM

Infection of a dental implant is undesirable and decreases the success rate of the dental prosthesis; however, systematic reviews on the issue are lacking.

PURPOSE

The purpose of this systematic review was to evaluate studies that dealt with inherent factors or those applied to the titanium surface or alloys to provide an antimicrobial action.

MATERIAL AND METHODS

SCOPUS, PubMed/Medline, Web of Science, EMBASE, and Science Direct databases were searched and manual searches made between June and July 2019 using the keywords "titanium," "surface," "implants," "photoelectron spectroscopy," and "fourier transform infrared spectroscopy." The criteria included in vitro studies evaluating the titanium surface and describing hydrophobicity, surface crystalline phase, nanotopography, surface charges, and their relationship with bacteria and/or osseointegration.

RESULTS

A comprehensive search identified 767 articles that were selected by the title and/or abstract as per the inclusion criteria. Of the 58 studies selected for full reading, 7 were used for this systematic review. Another 6 studies were added by further research, resulting in 13 articles, all in vitro studies. As the selected studies had a high heterogeneity that precluded any statistical analysis of the data, a descriptive analysis of these topics was performed: hydrophilicity, surface crystalline phase, nanotopography, and surface charges.

CONCLUSIONS

The articles analyzed in this systematic review suggest that hydrophilicity, crystalline phase, surface topography, and surface titanium charge, when altered, may provide an antimicrobial surface. However, the strategy used resulted in heterogeneous articles, making it impossible to demonstrate the unique effect of the electrostatic surface of titanium or titanium alloy used for implants and its effect on bacterial control.

Cytotoxicity and release ions of endodontic sealers incorporated with a silver and vanadium base nanomaterial

The modification of endodontic sealers with nanoparticles to confer antimicrobial activity allow greater effect, with interaction at a molecular level. The nanostructured silver vanadate decorated with silver nanoparticles (AgVO₃) is a nanomaterial unprecedented in dentistry for this application. This study incorporated the AgVO₃ into three endodontic sealers of different compositions and evaluate the cytotoxicity and release of compounds. The groups of commercially available AH Plus, Sealer 26, and Endomethasone N and groups of the same sealers with incorporated AgVO₃ (at concentrations 2.5, 5, 10%) were prepared, and extracts of the specimens were obtained for 24 h. The cell viability (cytotoxicity) of human gingival fibroblasts (HGF) was assessed after 24 h, 7 and 14 days. Silver (Ag⁺) and vanadium (V⁴⁺/V⁵⁺) ion release was quantified after 24 h by ICP-MS. Data were analyzed by Kruskal-Wallis and Dunn's post-hoc (α = 0.05). The cell viability was inversely proportional to treatment time. The Sealer 26 and Endomethasone N groups were cytotoxic for HGF cells, regardless of the incorporation of the AgVO₃ (p > 0.05), and the incorporation reduced cell viability of AH Plus (p < 0.05). The release of ions was proportional to the concentration of AgVO₃. AH Plus released more Ag⁺ ions, and Sealer 26 and Endomethasone N releases more V⁴⁺/V⁵⁺ ions. In conclusion, it was not possible to confirm the influence of AgVO₃ on HGF cell viability to Sealer 26 and Endomethasone N, however, nanomaterial influenced cell-viability to AH Plus, so the commercial sealers can be cytotoxic in synergy with the nanomaterial. The release of Ag⁺ and V⁴⁺/V⁵⁺ was proportional to the AgVO₃ incorporated.

Effect of nanomaterial incorporation on the mechanical and microbiological properties of dental porcelain

STATEMENT OF PROBLEM

Dental porcelain restorations are subject to biological failures related to secondary caries and periodontal disease leading to prosthesis replacement.

PURPOSE

The purpose of this in vitro study was to explore the microbiological and mechanical properties of dental porcelain incorporated with different percentages of silver vanadate (β-AgVO₃) through microbiological analysis, roughness tests, and the Vickers microhardness test.

MATERIAL AND METHODS

IPS InLine porcelain specimens were made by using a cylindrical Teflon matrix in the dimensions of 8×2 mm. For the control group, the porcelain was manipulated according to the manufacturer's instructions. The groups incorporating the nanomaterial were prepared with 2.5%, 5%, and 10% of β-AgVO_3, which was added proportionally by mass to the porcelain powder. In vitro microbiologic analysis, roughness tests, and the Vickers microhardness test were performed.

RESULTS

Against Streptococcus mutans, the control group showed no inhibition halo (0 mm). All groups with AgVO₃ showed a zone of inhibition, the highest for the group with 10% (30 mm) and then the groups with 2.5% (9 mm) and 5% (17 mm). For Vickers microhardness, no statistically significant difference (P<.05) was observed between the evaluated groups. The group with 10% of AgVO₃ had the highest mean roughness and was statistically different (P<.001) from the other groups.

CONCLUSIONS

Adding β-AgVO₃ to dental porcelain demonstrated antimicrobial effectiveness at all concentrations (2.5%, 5%, and 10%), with no effect on Vickers microhardness. The 10% group had higher roughness than the other groups.

Relationship between temporomandibular dysfunctions, sleep disorders, and anxiety among dentistry students

Introduction: This study aimed to evaluate the relationship between temporomandibular dysfunction (TMD), anxiety, and sleep disorder (DS) among dentistry students, relating the periods in which they are enrolled.Methods: The study consisted of 90 students: Group 1: 30 first-period students; Group 2: 30 fifth-period students; Group 3: 30 students from the ninth period. The participants responded to the RDC/TMD, Fletcher & Luckett questionnaires, and the Beck Anxiety Inventory to analyze symptoms of TMD, DS, and anxiety.Results: There was an association between TMD, DS, and the period studied. When related to moderate and severe anxiety, the group that had the highest incidence was Group 1 (first period students).Conclusion: The apprehension for what is new can influence the TMD and DS indices, while the greater concern for academic/professional performance can generate higher levels of anxiety.

Effects of Denture Cleansing Solutions on Different Materials Used for Fabrication of Polymer Attachment Components

AIMS

To evaluate the effects of different cleansing solutions on the physical-mechanical properties (roughness, surface hardness, and fatigue resistance) of three polymeric materials used to manufacture retentive attachments for overdentures.

MATERIALS AND METHODS

The roughness and surface hardness analyses each employed 150 specimens measuring . 9 mm × 2 mm in thickness (polyacetal, polytetrafluoroethylene [PTFE], and polyethylene terephthalate [PET]; n = 50 each). For fatigue resistance analysis, 180 retentive attachments measuring 4 mm × 3 mm in height (n = 60 each) were used. The properties were evaluated before and after immersion in different cleansing solutions: distilled water, alkaline peroxide, 0.5% sodium hypochlorite (NaOCl), and Listerine. After the data distribution was verified using Shapiro-Wilk test, parametric or nonparametric analysis was applied (α = .05).

RESULTS

The use of NaOCl caused a significant alteration in the roughness of the materials (P = .011), with a reduction in roughness in polyacetal and an increase in PTFE. The type of solution also influenced the surface hardness (P = .036); with the exception of distilled water, the other solutions promoted increased hardness. During the 24-month period, immersion in water, peroxide, and NaOCl (0.5%) caused increased fatigue resistance (P < .05) of the PET attachments. The immersion protocol resulted in greater fatigue resistance (P < .05) in polyacetal, while PTFE was not affected (P > .05).

CONCLUSION

Regarding the physical-mechanical properties evaluated, the polymers PET, polyacetal, and PTFE were susceptible to cleansing solutions.

Influence of an Alternative Implant Design and Surgical Protocol on Primary Stability

The purpose of thisin vitrostudy was to evaluate the influence of a new proposal of implant design and surgical protocol on primary stability in different bone densities. Four groups were tested (n=9): G1 - tapered, cone morse, Ø 4.3 mm x 10 mm in length (Alvim CM); G2 - experimental tapered; G3 - cylindrical, cone morse, Ø 4.0 mm x 11 mm in length (Titamax CM) and G4 - experimental cylindrical. The experimental implants were obtained from a design change in the respective commercial models. The insertion was performed in polyurethane (PU) blocks 0.24 g/cm3(20 pcf) and 0.64 g/cm3(40 pcf), according to different surgical protocols. The primary stability was measured by means of insertion torque (IT) and pullout test. Data were analyzed by ANOVA, Tukey's test (α=0.05) and Pearson's correlation. For IT and pullout, conventional and experimental implants showed no difference between them when inserted in the 20 pcf PU (p>0.05). In the 40 pcf PU, the modified implants exhibited greater IT (p<0.05) and lower pullout (p<0.05) compared to the respective conventional models. The implant design tested associated with the surgical protocol, positively influenced primary stability in higher density bones.

Effect of Thermomechanical Fatigue on Shear Strength between a Conventional and an Experimental Polymer for Prosthetic Application

AbstractThe incorporation of antimicrobial agents may influence the mechanical properties of acrylic resins. Thus, the use of these agents only in regions of dental prostheses subject to greater contamination may be an alternative. This study evaluates the effect of thermomechanical fatigue on the bond strength between a conventional and an experimental acrylic resin incorporated with nanostructured silver vanadate decorated with silver nanoparticles (AgVO3). 60 specimens (Ø13mm x 23mm height) in self-curing resin were obtained and divided into groups according to the experimental resin incorporated with AgVO3 (Ø4mm x 6mm height): G1–Conventional x Conventional, G2–Conventional x 2.5% of AgVO3, G3–Conventional x 5% of AgVO3. Ten samples of each group were subjected to bond strength analysis after manufacture, and 10 were previously submitted to 1.200.000 cycles with 98N load and 2Hz/second frequency and alternating baths of 5 ºC, 37ºC and 55 ºC. The fracture area was analyzed.  The data were submitted to analysis of variance of two-factors with Bonferroni adjustment for post hoc comparisons (α=0.05) was used. The fatigue did not affect the bond strength (p=0.416), however, there was influence of the AgVO3 concentration on the bond strength between the resins (p=0.013). Mixed failures with adhesive predominance were observed in samples without AgVO3 and cohesive failures in samples with the nanomaterial. The use of AgVO3 can improve or maintain the bond strength between resins with no thermomechanical fatigue influence. Keywords: Acrylic Resins. Products with Antimicrobial Action. Nanotechnology. Thermomechanical fatigue ResumoA incorporação de agentes antimicrobianos pode influenciar nas propriedades mecânicas de resinas acrílicas. Desta forma, o uso destes agentes apenas em regiões das próteses dentárias sujeitas a maior contaminação pode ser uma alternativa. Este estudo avalia o efeito da fadiga termomecânica na resistência de união entre uma resina acrílica convencional e uma experimental incorporada com vanadato de prata nanoestruturado decorado com nanopartículas de prata (AgVO3). Foram obtidos 60 espécimes (Ø13mm x 23mm de altura) em resina autopolimerizável, divididos em grupos de acordo com a resina experimental incorporada com AgVO3 (Ø4mm x 6mm de altura): G1-Convencional x Convencional, G2-Convencional x 2,5% de AgVO3, G3 -Convencional x 5% de AgVO3. Dez amostras de cada grupo foram submetidas à análise de resistência à união após a confecção e 10 foram submetidas previamente a 1.200.000 ciclos com carga de 98 N e frequência de 2Hz/segundo e banhos alternados de 5 ºC, 37 ºC e 55 ºC. A área de fratura foi analisada. Os dados foram submetidos à análise de variância de dois fatores com ajuste de Bonferroni para comparações pos hoc (α = 0,05). A fadiga não afetou a força de união (p=0,416), no entanto, houve influência da concentração de AgVO3 na resistência de união entre as resinas (p=0,013). Falhas mistas com predominância adesiva foram observadas nas amostras sem AgVO3 e falhas coesivas nas amostras contendo o nanomaterial. O uso de AgVO3 pode melhorar ou manter a resistência da união entre as resinas sem influência da fadiga termomecânica. Palavras-chave: Resinas Acrílicas. Produtos com Ação Antimicrobiana. Nanotecnologia.

Influence of Adding Nanoparticles of Silver Vanadate on Antibacterial Effect and Physicochemical Properties of Endodontic Sealers

Introduction

The aim of this study was adding the nanostructured silver vanadate decorated with silver nanoparticles (AgVO₃) (0, 2.5, 5, and 10%) to the endodontic sealers AH-Plus, Sealer 26 and Endomethasone N, and evaluate the antimicrobial activity, solubility and pH.

Methods and Materials

The antimicrobial activity of freshly mixed sealers (n=10) and set sealers (n=9) against Enterococcus faecalis (E. faecalis) was evaluated by colony forming units per milliliter and epifluorescence microscopy. Solubility (n=9) and pH (n=10), 6 and 24 h and 7, 14, and 30 days were also evaluated. The Kruskal-Wallis and Dunn's post-test were applied for the antimicrobial activity of fresh sealers. ANOVA and Tukey's post-test was used for set sealers and solubility, and Friedman's two-way analysis of variance for pH (α=0.05).

Results

The fresh sealers inhibited E. faecalis. Set Sealer 26 (5 and 10% AgVO₃) and Endomethasone N (2.5, 5, and 10% AgVO₃) presented higher activity then the corresponding controls. Modification with AgVO₃ did not influence the solubility of AH Plus and Sealer 26, but Endomethasone N (5%) presented reduced solubility. The AH-Plus groups showed acidic pH, and Sealer 26, basic pH after 30 days. Endomethasone N (5 and 10% AgVO₃) presented statistical difference compared to 0% (P<0.05).

Conclusion

In this in vitro study all fresh sealers and set Sealer 26 (5 and 10%) and Endomethasone N (2.5, 5, and 10%) presented higher antimicrobial activity than controls. The modification with 5% and 10% AgVO₃ decreased solubility and pH of Endomethasone N, but did not affect the other groups.

Bond strength of resin cements to novel materials to intracanal posts applications

Objective: evaluate the bond strength of resin cements to new materials for application in intraradicular posts. Material and Methods: Five materials were evaluated: fiberglass, PET, polyethylene, polyacetal and PTFE. Two commercial resin cements (Rely X U200 and Rely X Arc) were applied on the test specimens of the materials (9x3mm) and the bonding was evaluated through the shear bond strength test, where the chisel operated with a load of 1kN and a velocity of 0.5mm/min at the cement/material interface. The data were analyzed by the Shapiro-Wilk test, followed by the two-way analysis of variance, performed with the Bonferroni post-test (?=0.05). Results: The glass fiber was statistically different from all evaluated materials (p<0.05). There was no statistically significant difference between the other materials (p>0.05). Comparing the two cements, a statistical difference was found between Rely X U200 and Arc only for the glass fiber (p=0). Conclusion: PET, polyethylene, polyacetal and PTFE exhibited reduced bond strength compared to the glass fiber.KeywordsResin cement; PET polymer; Polytetrafluoroethylene.

Analysis of the oral microbiome on the surface of modified dental polymers

OBJECTIVES

This study characterized the microbial diversity of formed biofilm on the surface of acrylic resins modified with nanostructured silver vanadate decorated with silver nanoparticles (AgVO₃) after incubation in human saliva.

DESIGN

Resin specimens prepared with AgVO₃ at concentrations 0%, 1%, 2.5%, and 5% by either vacuum mixing or polymer solubilization were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). After 24 h and 7 days of saliva incubation, biofilm samples were collected from the surface of the specimens. The 16S rDNA genes were amplified, sequenced with the 454-Roche next-generation sequencing platform and analyzed to identify the Operational Taxonomic Units at the genus or higher level.

RESULTS

Significant differences in the dispersion pattern of the nanoparticles were observed among the two different methods of AgVO₃ incorporation. In the microbiological analysis, a total of 103 genera and 7 more inclusive taxa, representing the phyla Bacteroidetes, Firmicutes and Proteobacteria were identified colonizing resin surfaces. The incorporation method of the AgVO₃ had little to no significant effect on the microbiota of samples. Significant time and concentration-dependent responses to AgVO₃ caused changes in the taxonomic profile at the phylum and genus level.

CONCLUSIONS

The results show differences in relation to the microbial diversity of modified resins during the initial phase of biofilm maturation. The incorporation of AgVO₃ seems to significantly affect the colonizing microbiota.

Surface treatment of implant materials with antimicrobial nanoparticulates

This study analyzed nanostructured silver vanadate (AgVO3) films on certain substrate surfaces found in dental implant devices in order to see if these films promote antimicrobial activity. Enamel and glaze vehicles were used to apply the nanomaterial (0.0% [control], 2.5%, 5.0%, and 10.0% concentrations) on 3 substrates (280 specimens per substrate): polytetrafluoroethylene (PTFE), polyacetal, and acrylic resin. An agar diffusion method was performed in triplicate to determine the antimicrobial activity against 8 microorganisms. Physical behavior and morphologic properties were also analyzed. The growth of Pseudomonas aeruginosa, Escherichia coli, Streptococcus mutans, Enterococcus faecalis, and Staphylococcus aureus was inhibited with the application of AgVO3. For Candida albicans, Porphyromonas gingivalis, and Prevotella intermedia, no antimicrobial activity was observed. Except for S mutans, the type of substrate did not influence the microbiologic results. The glaze showed greater antimicrobial efficacy against S aureus, E faecalis, and S mutans than did the enamel vehicle (P < 0.05). Films with 10% AgVO3 showed greater antimicrobial activity (P < 0.05). The choice of substrate or vehicle did not influence the surface roughness (P > 0.05); however, the application of 10% AgVO3 caused greater surface change (P < 0.05). The application of the nanomaterial did not influence the surface hardness of substrates when compared with the control group (P > 0.05). The use of the glaze as a vehicle provided higher hardness values (P < 0.05).

Elemental ion release and cytotoxicity of antimicrobial acrylic resins incorporated with nanomaterial

OBJECTIVES

This study evaluated the release of ions and the cytotoxicity of acrylic resins incorporated with silver vanadate decorated with silver nanoparticles (AgVO₃ ).

BACKGROUND

The inhibition of the accumulation of microorganisms on the resins is critical in preventing diseases. However, the hypothesis is that the release of ions from the incorporation of AgVO₃ may be important in biocompatibility.

MATERIALS AND METHODS

Specimens of autopolymerising (AP) and heat-polymerising resin (HP) with AgVO₃ were prepared and immersed in culture medium. The release of silver ions (Ag) and vanadium (V) was evaluated by mass spectrometry with inductively coupled plasma (ICP-MS) (n=9) and the cell viability of fibroblasts L929 by MTT (3-[4,5-dimethylthiazol- 2yl]-2,5-diphenyltetrazolium bromide) (n=12). The results were evaluated with analysis of variance (ANOVA), Tukey and Pearson correlation test (α=.05).

RESULTS

The groups containing AgVO₃ presented a difference in relation to the control (0%) regarding the release of Ag and V (P<.0001). All groups showed a reduction in L929 viability when compared with the cellular control (100%) (P<.0001). In comparison with the control resins for HP, a reduction in the metabolism of cells occurred starting at 2.5% and for AP at 5% (P<.0001). A positive correlation was found between the concentration of AgVO₃ and the ion release, and a negative between the ion release and the cell viability.

CONCLUSIONS

Significant numbers of Ag and V ions were released from resins with higher concentrations of AgVO₃ , presenting cytotoxicity for cells, suggesting that the use of low concentrations is indicated to avoid risks to patients.

Esthetic solution to malpositioned implants with remodeling of soft tissue: a case report

This article describes a clinical case of gingival conditioning with provisional fixed prostheses to improve the esthetics of the soft tissues adjacent to fixed prostheses placed on malpositioned implants. Gradual application of pressure to the tissues is an easy, nontraumatic technique for inducing formation of papillae and reestablishing the appropriate shape and contour of the gingival tissues, thereby improving esthetics and phonetics. The proposed treatment proved to be effective in remodeling the surrounding soft tissues, providing suitable contours, and restoring esthetics and function lost due to surgical treatment with malpositioned implants.