Influence of building direction on physical and mechanical properties of titanium implants: A systematic review.

The objective of the systematic review is to find an answer to a question: "What is the influence of the building direction of titanium implants produced by additive manufacturing on their physical and mechanical properties?" This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA 2020) and was registered in the Open Science Framework (OSF) (osf.io/rdc84). Searches were performed in PubMed, Scopus, Science Direct, Embase, and Google Scholar databases on February 17th, 2024. Articles were chosen in 2 steps by 2 blinded reviewers based on previously selected inclusion criteria: In vitro studies that evaluated the influence of the impression direction of titanium implants produced by additive manufacturing on their physical and mechanical properties were selected. Articles were excluded that (1) did not use additive technology to obtain the implants, 2) used surfaces other than titanium, 3) did not evaluate the direction of impression, 4) Studies with only in vivo analyses, clinical studies, systematic reviews, book chapters, short communications, conference abstracts, case reports, and personal opinions.). In the initial search, 581 results were found. Of this total, 108 were excluded for duplication and, after applying the eligibility criteria, 16 articles were included in the present review. The risk of bias was analyzed using the RoBDEMAT. The risk of bias was analyzed using the RoBDEMAT. In addition, the coefficient of interagreement of the reviewers (Cohen's Kappa) and the certainty of evidence by GRADE were analyzed. In general, different impression angles showed variations in the physical and mechanical characteristics of the groups evaluated, including roughness, tensile strength, hardness, and modulus of elasticity. While some impression orientations resulted in greater strength or hardness, others showed greater elasticity or lower surface roughness. These findings suggest that print orientation plays a significant role in determining material properties. It can be concluded that printing directions influence the physical and mechanical properties of titanium implants and the studies included showed that the 0°, 45°, and 90° directions are the most evaluated as they present lower probabilities of structural anisotropies and provide better results in their roughness, hardness, tensile and compressive strength.

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.

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.

Mechanical and microbiological properties of orthodontic resin modified with nanostructured silver vanadate decorated with silver nanoparticles (ßAgVO3).

OBJECTIVE: To investigate the impact of incorporating the antimicrobial nanomaterial ß-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 ß-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 ß-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.

Osseointegration in additive-manufactured titanium implants: A systematic review of animal studies on the need for surface treatment.

The objective of the systematic review is to find an answer to a question: "Do surface treatments on titanium implants produced by additive manufacturing improve osseointegration, compared to untreated surfaces?". This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA 2020) and was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42022321351). Searches were performed in PubMed, Scopus, Science Direct, Embase, and Google Scholar databases on March 22nd, 2022. Articles were chosen in 2 steps by 2 blinded reviewers based on previously selected inclusion criteria: articles in animals that addressed the influence of surface treatments on osseointegration in implants produced by additive manufacturing. Articles were excluded that (1) did not use titanium surface, 2) that did not evaluate surface treatments, 3) that did not described osseointegration, 4) Studies with only in vitro analyses, clinical studies, systematic reviews, book chapters, short communications, conference abstracts, case reports and personal opinions.). 1003 articles were found and, after applying the eligibility criteria, 17 were used for the construction of this review. All included studies found positive osseointegration results from performing surface treatments on titanium. The risk of bias was analyzed using the SYRCLE assessment tool. Surface treatments are proposed to promote changes in the microstructure and composition of the implant surface to favor the adhesion of bone cells responsible for osseointegration. It is observed that despite the benefits generated by the additive manufacturing process in the microstructure of the implant surface, surface treatments are still indispensable, as they can promote more suitable characteristics for bone-implant integration. It can be concluded that the surface treatments evaluated in this systematic review, performed on implants produced by additive manufacturing, optimize osseointegration, as it allows the creation of a micro-nano-textured structure that makes the surface more hydrophilic and allows better contact bone-implant.

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.

Adhesion of biofilm, surface characteristics, and mechanical properties of antimicrobial denture base resin.

PURPOSE: This study incorporated the nanomaterial, nanostructured silver vanadate decorated with silver nanoparticles (AgVO3), into heat-cured resin (HT) at concentrations of 2.5%, 5%, and 10% and compared the adhesion of multispecies biofilms, surface characteristics, and mechanical properties with conventional heat-cured (HT 0%) and printed resins. MATERIALS AND METHODS: AgVO3 was incorporated in mass into HT powder. A denture base resin was used to obtain printed samples. Adhesion of a multispecies biofilm of Candida albicans, Candida glabrata, and Streptococcus mutans was evaluated by colony-forming units per milliliter (CFU/mL) and metabolic activity. Wettability, roughness, and scanning electron microscopy (SEM) were used to assess the physical characteristics of the surface. The mechanical properties of flexural strength and elastic modulus were tested. RESULTS: HT 10%-AgVO3 showed efficacy against S. mutans; however, it favored C. albicans CFU/mL (P < .05). The printed resin showed a higher metabolically active biofilm than HT 0% (P < .05). There was no difference in wettability or roughness between groups (P > .05). Irregularities on the printed resin surface and pores in HT 5%-AgVO3 were observed by SEM. HT 0% showed the highest flexural strength, and the resins incorporated with AgVO3 had the highest elastic modulus (P < .05). CONCLUSION: The incorporation of 10% AgVO3 into heat-cured resin provided antimicrobial activity against S. mutans in a multispecies biofilm did not affect the roughness or wettability but reduced flexural strength and increased elastic modulus. Printed resin showed higher irregularity, an active biofilm, and lower flexural strength and elastic modulus than heat-cured resin.

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 µÎµ [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 µÎµ [-173; 162] (p = .009) and 242 µÎµ [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.

Influence of surface treatment by laser irradiation on bacterial adhesion on surfaces of titanium implants and their alloys: Systematic review.

Objective: The aim of this systematic review was to present the current knowledge on the influence of laser surface treatment on the adhesion of bacteria to titanium and its alloys. Design: This review was structured according to PRISMA guidelines for systematic reviews and meta-analyses, and registered on the Open Science Framework platform (https://doi.org/10.17605/OSF.IO/FTA3W). Article searches were performed in 4 databases: PubMed, Scopus, Embase, and Science Direct. In addition, a manual search was performed in the reference lists of the selected articles. The selection of articles was performed by two reviewers. The articles found were screened for eligibility using the previously established inclusion and exclusion criteria. The methodological quality of the studies was assessed using the Joanna Briggs Institute (JBI) Critical Assessment Checklist for Quasi-Experimental Studies (non-randomized experimental studies). Results: Most of the studies evaluated showed that surface treatment by laser irradiation can affect the adhesion of bacteria to titanium surfaces and that this is directly related to changes in surface properties such as chemical composition, morphology, roughness, and wettability, as well as the type of bacterial species involved. Conclusions: The studies considered in this systematic review have shown that surface treatment by laser irradiation is a promising technique to reduce the adhesion of bacteria on the surface of titanium implants.

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.

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.

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.

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.

Influence of ß-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 (ß-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 ß-AgVO3, influenced the mechanical properties of the material and demonstrated antimicrobial activity at certain concentrations.

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 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.

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 (ß-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 ß-AgVO3, 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 ß-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.

Prótese de Transição x Prótese sobre Implantes: Relato de Caso / Transitional Prosthesis x Implant-Supported Prosthesis: Case Report

Objetivo: O objetivo desse trabalho foi descrever um caso clínico, realizado na Faculdade de Odontologia de Ribeirão Preto ­ Universidade de São Paulo, com adaptação da prótese parcial removível do paciente em prótese total provisória de transição, após a instalação de implantes odontológicos. Material e método: O paciente era usuário de prótese parcial removível associada à prótese parcial fixa inferior, cujos pilares eram os elementos 42 e 44. Ambos os dentes apresentavam indicação para extração. Após a remoção da prótese fixa e extração dos dentes 42 e 44, foram instalados quatro implantes na região anterior da mandíbula, e confeccionada uma prótese total de transição, a partir da prótese parcial removível do paciente. Após o período de osseointegração, a prótese sobre implantes definitiva foi confeccionada. Conclusão: A adaptação de prótese parcial removível em prótese total provisória de transição reduz o tempo dos procedimentos clínicos e o custo do tratamento, permitindo ao paciente a manutenção de suas funções orais, até a confecção da prótese definitiva.

Objective: The aim of this study was to describe a case, performed at the Dental School of Ribeirão Preto - University of São Paulo, with adaptation of the removable partial denture of the patient in a transitional denture after the installation of dental implants. Material and Methods: Patient was a user of a mandibular removable partial denture associated with fixed partial dentures, whose pillars were teeth 42 and 44, both indicated for extraction. After removal of the fixed partial dentures and extraction of 42 and 44, four implants were installed in the anterior region of the mandible, and a transitional denture was made from the patient's removable partial denture. After the period of osseointegration, the definitive implant prosthesis was made. Conclusions: The adaptation of a removable partial denture in a transitional denture reduces the time of the clinical procedures and the cost of the treatment, allowing to the patient to maintain his/her oral functions, until the definitive implant prosthesis is made.

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.

Use of polyethylene terephthalate as a prosthetic component in the prosthesis on an overdenture implant.

The aim of this study was to evaluate the physical-mechanical and morphological properties of polyethylene terephthalate (PET), for a new application as a prosthetic component for overdentures implant-retained, compared with different polymers. Were prepared 20 specimens for each material: Polyethylene terephthalate (PET), Polyacetal, Polytetrafluoroethylene (PTFE) and Polyethylene, for analysis of roughness and hardness surface, compressive strength and pull out test. For fatigue strength test, a total of 200 capsules (n = 40) were captured in pairs with acrylic resin and subjected to 2900 insertion/removal cycles, simulating 24 months of overdenture use. In this test, a group was added (o-ring Intra-Lock System) as a standard of comparison. The morphological and structural analysis were realized by stereomicroscopy, scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD). All specimens in this study were analyzed before and after thermocycling (5-55 °C, for 10,000 cycles). Two-way ANOVA with repeated measurements and Tukey test were used (α = 0.05). For roughness, difference was observed only between the materials, with lowest averages for Polyacetal and PET (p < 0.001). For the hardness there was no statistically significant difference between the materials (p > 0.001). For compressive strength, Polyacetal, followed by PET (p < 0.001) presented the highest values independent of thermocycling. In the pullout test, PET and polyacetal presented, the highest values (p = 0.033). In the fatigue test, for 24 months analysis, difference was observed before and after thermocycling for O-ring group (p = 0.010) and polyacetal (p = 0.002), PET also presented higher values of resistance in relation to the o-ring (p < 0.001). The thermocycling did not alter the polyethylene surface through SEM images as well as the structure of all the materials analyzed by FTIR and DRX. In this study, the PET presented results compatible with those expected, which suggests its application for making retention capsules for implant-retained overdentures.