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The objective of this study was to evaluate microbial leakage by means of genome counts, through the implant-abutment interface in dental implants with different Morse taper abutments. Fifty-six samples were prepared and divided in four groups: CMC TB (14 Cylindrical Implants-14 TiBase Abutments), CMX TB (14 Conical Implants-14 TiBase Abutments), CMX PU (14 Conical Implants-14 Universal Abutment) and CMX U (14 Tapered Implants-14 UCLA Abutments). Assemblies had their interface submerged in saliva as the contaminant. Samples were subjected either to thermomechanical cycling (2 × 106 mechanical cycles with frequency of 5 Hz and load of 120 N simultaneously with thermal cycles of 5-55 °C) or thermal cycling (5-55 °C). After cycling, the contents from the inner parts of assemblies were collected and analyzed using the Checkerboard DNA-DNA hybridization technique. Significant differences in the total genome counts were found after both thermomechanical or thermal cycling: CMX U > CMX PU > CMX TB > CMC TB. There were also significant differences in individual bacterial counts in each of the groups (p < 0.05). Irrespective of mechanical cycling, the type of abutment seems to influence not only the total microbial leakage through the interface, but also seems to significantly reflect differences considering individual target species.

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BACKGROUND: The aim of this case study is to present the rationality and scientific evidence of a new design for a double (DA) and triple (TA) dental abutment-implant with their specific new concept of biodynamic optimized peri-implant tissue (BOPiT). METHODS: The innovative design of these abutments with a paraboloid geometry was based on BOPiT, simultaneously involving the principles of mechanobiology, biotensegrity, and mechanotransduction. Thus, 37 consecutive individuals/43 cases rehabilitated with single dental implant using the innovative DA (n = 28) and TA (n = 15) on 43 implants were included in this case study. The DA and TA support 2 or 3 dental crowns on a single implant, respectively. Clinic and radiographic examinations were presented at T1 (loading after 4 months) and T2 [final examination with an average follow-up time of 7.2 years (>3 to 12 years)]. RESULTS: At T2, mean scores for plaque index, peri-implant bleeding on probing, and peri-implant probing depth were low, depicting healthy peri-implant conditions. All radiographic images showed insignificant annual marginal bone loss (0.022 ± 0.05 mm) when compared to T1, reflecting great bone stability. CONCLUSION: DA and TA, based on the BOPiT concept, represent an advantageous, simple and non-invasive mechanism for the longevity and healthy regulation of the peri-implant tissues.

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A eficácia dos implantes osseointegrados é amplamente reconhecida na literatura científica. Contudo, infiltrações bacterianas na junção implante-pilar podem desencadear inflamação nos tecidos circundantes, contribuindo para a evolução de condições mais sérias, como a peri-implantite. O objetivo desse estudo foi produzir complexos polieletrólitos (PECs) de quitosana (Q) e xantana (X) em forma de membranas, carregá-las com ativos naturais e sintéticos antimicrobianos, caracterizálas estruturalmente e avaliá-las frente a degradação enzimática, cinética de liberação e ações antimicrobianas com finalidade de aplicação para drug delivery. Membranas de QX a 1% (m/v) foram produzidas em três proporções, totalizando doze grupos experimentais: QX (1:1); QX (1:2), QX (2:1), QX-P (com própolis) (1:1); QX-P (1:2); QX-P (2:1); QX-C (com canela) (1:1); QX-C (1:2); QX-C (2:1) e CLX (com clorexidina 0,2%) (1:1); CLX (1:2); CLX (2:1). Para os estudos de caracterização foram feitas análises da espessura em estado seco; análises morfológicas superficial e transversal em Microscopia Eletrônica de Varredura (MEV); análise estrutural de espectroscopia de infravermelho por transformada de Fourier (FTIR); análise de degradação por perda de massa sob ação da enzima lisozima; e análise da cinética de liberação dos ativos em saliva artificial. Para os testes microbiológicos, análises de verificação de halo de inibição e ação antibiofilme foram feitas contra cepas de Staphylococcus aureus (S. aureus) e Escherichia coli (E. coli). Os resultados demonstraram que a espessura das membranas variou conforme a proporção, sendo que o grupo QX (1:2) apresentou a maior média de 1,022 mm ± 0,2, seguida respectivamente do QX (1:1) com 0,641 mm ± 0,1 e QX (2:1) com 0,249 mm ± 0,1. Nas imagens de MEV é possível observar uma maior presença de fibras, rugosidade e porosidade nos grupos QX (1:2) e QX (1:1) respectivamente, e, no QX (2:1) uma superfície mais lisa, uniforme e fina. No FTIR foram confirmados os picos característicos dos materiais isoladamente, além de observar as ligações iônicas que ocorreram para formação dos PECs. Na análise de degradação, os grupos com ativos naturais adicionados tiveram melhores taxas de sobrevida do que os grupos QX. No teste de liberação, os grupos QX-P tiveram uma cinética mais lenta que os QX-C, cuja liberação acumulada de 100% foi feita em 24 h. Já nos testes do halo inibitório, somente os grupos CLX tiveram ação sobre as duas cepas, e os QX-P tiveram sobre S. aureus. Nas análises antibiofilme, os grupos CLX apresentaram as maiores taxas de redução metabólica nas duas cepas (± 79%); os grupos QX-P apresentaram taxas de redução similares em ambas as cepas, porém com percentual um pouco maior para E. coli (60- 80%) e os grupos QX-C tiveram grande discrepância entre as duas cepas: de 35 a 70% para S. aureus e 14 a 19% para E. coli. Pode-se concluir que, frente as análises feitas, o comportamento do material foi afetado diretamente pelos ativos adicionados a matriz polimérica. As proporções de Q ou X afetaram somente a espessura final. Quanto a aplicação proposta de drug delivery, os dispositivos apresentaram grande potencial, principalmente os grupos CLX e QX-P. (AU)

The effectiveness of osseointegrated implants is widely recognized in scientific literature. However, bacterial infiltrations at the implant-abutment interface may trigger inflammation in surrounding tissues, contributing to the development of more serious conditions, such as peri-implantitis. The aim of this study was to produce chitosan (Q) and xanthan (X) polyelectrolyte complexes (PECs) in the form of membranes, load and evaluate them for enzymatic degradation, release kinetics, and antimicrobial actions for drug delivery applications. QX membranes at 1% (w/v) were produced in three proportions, totaling twelve experimental groups: QX (1:1), QX (1:2), QX (2:1), QX-P (with propolis) (1:1), QX-P (1:2), QX-P (2:1), QX-C (with cinnamon) (1:1), QX-C (1:2), QX-C (2:1), and CLX (with 0.2% chlorhexidine) (1:1), CLX (1:2), CLX (2:1). Characterization studies included analyses of dry state thickness, surface and crosssectional morphology using Scanning Electron Microscopy (SEM), structural analysis by Fourier Transform Infrared (FTIR) spectroscopy, mass loss degradation analysis under lysozyme action, and active release kinetics analysis in artificial saliva. Microbiological tests included verification analyses of inhibition halos and antibiofilm action against strains of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Results showed that membrane thickness varied according to proportion, with group QX (1:2) presenting the highest average of 1.022 mm ± 0.2, followed by QX (1:1) with 0.641 mm ± 0.1, and QX (2:1) with 0.249 mm ± 0.1. SEM images showed greater presence of fibers, roughness, and porosity in groups QX (1:2) and QX (1:1) respectively, while QX (2:1) exhibited a smoother, more uniform, and thinner surface. FTIR confirmed characteristic peaks of the materials individually, besides showing ionic bonds formed for PECs. Degradation analysis revealed that groups with added natural actives had better survival rates than QX groups. In release tests, QX-P groups exhibited slower kinetics than QX-C, with 100% cumulative release achieved in 24 h. inhibitory halo tests, only CLX groups exhibited action against both strains, while QX-P acted against S. aureus. Antibiofilm analyses showed CLX groups with the highest metabolic reduction rates in both strains (± 79%); QX-P groups showed similar reduction rates in both strains, slightly higher for E. coli (60-80%), and QX-C groups had a significant discrepancy between strains: 35-70% for S. aureus and 14-19% for E. coli. In conclusion, material behavior was directly affected by added actives to the polymeric matrix. Proportions of Q or X only affected final thickness. Regarding proposed drug delivery applications, the devices showed great potential, especially CLX and QX-P groups.(AU)

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BACKGROUND: Peri-implant disease prevalence is associated with a multifactorial etiology and distinct clinical characteristics of inflammation. METHODS: The present study aimed to assess the prevalence of peri-implant diseases, identify related risk indicators, and associate specific clinical characteristics to peri-implant biological complications in the medium term. Peri-implant diseases were classified according to established case criteria. Patients' data, implant and/or prosthetic features, and maintenance records were collected. Clinical characteristics such as bleeding on probing (BOP), suppuration (SUPP), keratinized mucosa (KM), probing depth (PD), marginal recession (MR), and modified plaque index (mPI) were recorded. RESULTS: Ninety-nine patients with 266 implants with a mean functional duration of 30.26 months were evaluated. Peri-implant mucositis and peri-implantitis prevalence totaled to 49.5% and 15.15% (patient level), respectively. Peri-implant mucositis was associated with osteoporosis (odds ratio [OR] 6.09), age (OR 0.97), diabetes mellitus (OR 3.09), cemented-retained prosthesis (OR 3.81), and partial prosthesis (OR 2.21). Peri-implantitis was associated with osteoporosis (OR 7.74) and periodontitis (OR 2.74), cemented prosthesis (OR 10.12), partial and full arch prostheses (OR 12.35 and 19.86), implant diameter (OR 3.64), abutment transmucosal height (OR 3.39), and hygiene difficulty (OR 3.14). Furthermore, mPI score 3 (OR 3.27) and PD scores (OR 1.64) were associated with peri-implant mucositis, while mPI score 3 (OR 16.42), KM (OR 1.53), PD (OR 1.81), MR (OR 2.61), and the relationship between KM and PD (OR 0.63) were associated with peri-implantitis. CONCLUSION: In the medium term, peri-implant diseases were correlated with factors inherent to the patient's conditions, presurgical treatment plan, and hygiene maintenance care. The knowledge of the mentioned factors and featured clinical characteristics can be crucial for disease prevention and establishment of a superior implant therapy prognosis.

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Background and Objectives: The insertion of the dental implant in the bone is an essential step in prosthetic rehabilitation. The insertion torque has the potential to distort the prosthetic platform, which can cause future biomechanical problems with the continuous action of occlusal forces. The aim of this study is to evaluate different insertion torques in the deformation of tri-channel platform connections through two- and three-dimensional measurements with micro-CT. Materials and Methods: A total of 164 implants were divided into groups (platform diameter and type): 3.5, 3.75, and 4.3 mm NP (narrow platform), and 4.3 mm RP (regular platform). Each implant-platform group was then divided into four subgroups (n = 10) with different torques: T45 (45 Ncm), T80 (80 Ncm), T120 (120 Ncm), and T150 (150 Ncm). The implant-abutment-screw assemblies were scanned and the images obtained were analyzed. Results: A significant difference was observed for the linear and volume measures between the different platforms (p < 0.01) and the different implant insertion torques (p < 0.01). Qualitative analysis suggested a higher deformation resistance for the 3.75 NP compared to the 3.5 NP, and RP was more resistant compared to the NP. Conclusions: The 0.25 mm increment in the implant platform did not increase the resistance to the applied insertion torques; the 4.3 mm implant was significantly stronger compared to the 3.5 mm implant; and the proposed micro-CT analysis was considered valid for both the 2D and 3D analyses of micro-gaps, qualitatively and quantitatively.

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This study investigated the effects of antirotational titanium bases on the mechanical behavior of CAD/CAM titanium bases used for implant-supported prostheses. The aim was to assess the impact on the marginal fit, fatigue behavior, stress concentration, and fracture load of implant-supported CAD/CAM zirconia crowns. Forty titanium implants were divided into two groups: those with antirotational titanium bases (ARs) and those with rotational titanium bases (RTs). Torque loosening and vertical misfit were evaluated before and after cyclic fatigue testing (200 N, 2 Hz, 2 × 106 cycles). Fracture resistance was assessed using a universal testing machine (1 mm/min, 1000 kgf), and failed specimens were examined with microscopy. Three-dimensional models were created, and FEA was used to calculate stress. Statistical analysis was performed on the in vitro test data using two-way analysis of variance and Tukey's test (α = 0.5). Results show that the presence of an antirotational feature between the implant and titanium base reduced preload loss and stress concentration compared to rotational titanium bases. However, there were no differences in vertical misfit and resistance to compressive load.

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The relationship between bacterial infiltration and internal conical Implant-Abutment Interfaces (IAIs) with different conicities still requires investigations that can offer valuable information in the clinical understanding of peri-implant health. The present study aimed to verify the bacterial infiltration of two internal conical connections with an angulation of 11.5° and 16° with the external hexagonal connection as a comparative after thermomechanical cycling using saliva as a contaminant. Test (n = 10) and control (n = 3) groups were set up. Evaluations were made on torque loss, Scanning Electron Microscopy (SEM), and Micro Computerized Tomography (MicroCT) after performing 2 × 106 mechanical cycles (120 N) and 600 thermal cycles (5°-55° C) with 2 mm lateral displacement. The contents of the IAI were collected for microbiological analysis. There was a difference (p < 0.05) in torque loss of the groups tested; groups from the 16° IAI obtained a lower percentage of torque loss. All groups presented contamination and the analysis of the results shows that the microbiological profile of the IAI differs qualitatively from the profile found in the saliva used for contamination. The mechanical loading affects the microbiological profile found in the IAIs (p < 0.05). In conclusion, the IAI environment may favor a microbiological profile different from that of saliva and the thermocycling condition may alter the microbial profile found in the IAI.

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Short dental implants with platform matching connection have been used for the rehabilitation of atrophic jaws whenever standard-length dental implants cannot be placed without prior bone augmentation. Yet, there remains a lack of data regarding the risk of technical failures when the all-on-4 configuration is performed in atrophic jaws with platform-switching distal short dental implants. Thus, the current study used the finite element method to evaluate the mechanical behavior at the level of the prosthetic components of the all-on-4 concept performed in atrophic mandible using short-length distal implants with platform switching (PSW) connection. Three models of the all-on-4 configuration were generated in human atrophic mandibles. The geometric models consisted of PSW connection tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) and straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants. A resultant force of 300 N was performed obliquely in the left side and posterior region of the prosthetic bar. The von Mises equivalent stress (σvm) and maximum and minimum principal stresses (σmax and σmin) were performed at level of the prosthetic components/implants and peri-implant bone crest, respectively. The general displacement of the models was also evaluated. The stress analysis was performed on the side of load application. The AO4S configuration showed the lowest values of σvm in the mesial left (ML) and distal left (DL) abutments (37.53 MPa and 232.77 MPa, respectively) and dental implants (91.53 MPa and 231.21 MPa, respectively). The AO4Sh configuration showed the highest values of σvm in the bar screw (102.36 MPa), abutment (117.56 MPa), and dental implant (293.73 MPa) of the ML area. Among the models, the highest values of σmax and σmin were noticed in the peri-implant bone crest of the AO4T design (131.48 MPa and 195.31 MPa, respectively). All models showed similar values of general displacements, which were concentrated in the mandible symphysis. The all-on-4 configurations designed with PSW connection and tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) or straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants were not associated with higher odds of technical failures. The AO4Sh design may be a promising option for the prosthetic rehabilitation of atrophic jaws.

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This study evaluated the influence of different implant diameters, insertion torques, and transmucosal heights on the loosening of abutments installed on short implants, after mechanical cycling. The Morse taper connection implants (n = 96) tested were 5 mm high, divided according to the platform diameter: 4 or 6 mm. A universal abutment was coupled to each implant (with different transmucosal heights: 1 or 5 mm). The sets were subdivided into 20- and 32-Ncm torque. After the cycle fatigue test, the detorque values were measured with a digital torque indicator. After mechanical cycling, the mean detorque values obtained for the abutment with 20-Ncm insertion torque were lower than for implants with 32-Ncm insertion torque, regardless of the platform diameter or transmucosal height. In the 20-Ncm torque group, there was no statistically significant difference in the detorque values between platform diameters or transmucosal heights. Otherwise, for 32-Ncm sets, a smaller platform diameter (4 mm), and a longer transmucosal height (5 mm) showed the lowest detorque values. In conclusion, implants placed with 32-Ncm insertion torque and abutments with 1 mm transmucosal height and a 6 mm implant diameter demonstrated the highest detorque values.

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This study investigated the influence of mechanical cycling on screwed-in and tappedin implants restored with screw-retained metallic crowns. Three implant-abutmentcrown systems were evaluated: T1 (multi abutment) and T2 (standard abutment) received tapped-in abutments and S received a screwed-in abutment. The specimens were subjected to two million cycles of 0-150 N load, at 2 Hz, 30° inclination in a dry medium, and torque evaluation. Survival and removal torque were analyzed using chisquare, ANOVA, followed by Tukey's test. Differences between installation and removal torque were determined using a T-test for dependent samples. Analyses were performed in SPSS, considering α = 0.05. All specimens survived mechanical cycling in S, 40% in T1, 80% in T2 (p=0.008). Failures occurred due to loosening of the crown screw. A significant decrease in torque (p=0.000) was found. Group T1 had the lowest removal torque (1.6 ± 0.84 N.Cm²), followed by T2 (3 ± 1.49 N.Cm²) and S (6.3 ± 1.16 N. Cm²), and a statistical difference was found between Groups T1 and S. Both types of implantabutment connections were stable and can be considered for rehabilitative treatment, but failure and removal torque were influenced by the design of prosthetic abutment. Crowns were more susceptible to becoming loose in tapped-in systems.

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Aim: This study aims to evaluate the clinical assessment results of periimplant soft tissue with morse taper (internal abutment connection). Methods: The study was conducted using a rapid review by searching the articles from PubMed NCBI and Cochrane by using keywords. All articles were selected by the year, duplication, title, abstract, full-text, and finally, all selected articles were processed for final review. Following clinical parameters were included; Periimplant Probing Pocket Depth (PPD), Plaque Score (PS), modified Plaque Index (mPI), Mucosal Thickness (MTh), Gingival Height (GH), periimplant mucosal zenith, Pink Esthetic Score (PES), Bleeding On Probing (BOP), Sulcus Bleeding Index (SBI), and modified Gingival Index (mGI). Results: 9 selected articles were obtained from the initial literature searching count of 70 articles. The overall samples included 326 morse taper implants. Based on the evaluation, 3 out of 4 articles reported pocket depth < 4 mm, no bleeding was reported in 2 out of 4 articles. 4 out of 4 articles reported low plaque accumulation, low soft tissue recession was reported in 3 out of 3 articles, and 4 out of 4 articles reported acceptable PES values. Conclusion: The evaluations indicate that the morse taper (internal abutment connection) has favorable assessment results based on various clinical parameters

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Este estudo teve o objetivo de avaliar o comportamento biomecânico de um novo pilar protético dividido em duas peças (P2P) comparado a um pilar padrão de uma peça (P1P), ambos com indicação para coroas unitárias parafusadas de um sistema de implante de conexão cônica, submetidos a ciclagem mecânica. Foram utilizados vinte implantes instalados em cilindros de resina poliacetal e divididos em dois grupos: P1P para restaurações ao nível da plataforma do implante, de conexão cônica anti-rotacional e parafuso passante e P2P para restaurações ao nível de tecidos, constituído de duas peças, uma base sólida (P2P-B), de conexão cônica rotacional e um pilar sobre a base (P2P-P), de conexão hexagonal interna antirotacional e parafuso passante. Os corpos de prova foram testados antes e após a ciclagem mecânica (200N a 4Hz por 1x106 ciclos) através da verificação da manutenção do torque em N.cm por um torquímetro digital e da análise das micro fendas em µm na conexão implante-pilar por microscopia. O grupo P1P apresentou redução significativa no torque de remoção pós-ciclagem 10,57 (±3,63) comparado ao torque pré-ciclagem 31,63 (±0,80) e torque de remoção inicial 26,48 (±1,60). O grupo P2P-B apresentou aumento significativo no torque de remoção pós-ciclagem 41,00 (±8,64), comparado ao torque pré-ciclagem 31,10 (±0,62) e torque de remoção inicial 30,12 (±2,08), sua parte superior P2P-P apresentou redução significativa no torque de remoção pós-ciclagem 14,85 (±2,06), comparado ao torque pré-ciclagem 21,06 (±0,50), porém não apresentou diferença significativa com o torque de remoção inicial 15,51 (±1,18). Na avaliação microscópica, a conexão implante-pilar nos dois grupos apresentaram micro fendas iniciais reduzidas, P1P 4,71 (±2,12) e P2P-B 3,95 (±2,02) as quais tiveram redução significativa após a ciclagem, P1P 0,006 (±0,001) e P2P-B 0,005 (±0,001). P2P apresentou comportamento biomecânico superior ao P1P nos valores de torque pós-ciclagem, nos vários momentos comparados, suportando seu uso para coroas unitárias. A interface de conexão de ambos os pilares exibiram micro fendas reduzidas sob microscopia, as quais foram praticamente eliminadas com o acoplamento produzido pela ciclagem mecânica. (AU)

This study aimed to evaluate the biomechanical behavior of a new two-piece split prosthetic abutment (P2P) compared to a standard one-piece abutment (P1P), both indicated for screw-retained single crowns of a conical connection implant system, subjected to mechanical cycling. Twenty implants installed in polyacetal resin cylinders were used and divided into two groups: P1P for implant platform-level restorations, with an anti-rotational conical connection and through screw, and P2P for tissue-level restorations, consisting of two pieces, a solid base (P2P-B), with a rotational conical connection, and an abutment on the base (P2P-P), with an internal hexagonal anti-rotational connection and through screw. The specimens were tested before and after mechanical cycling (200 N at 4 Hz for 1x106 cycles) by checking the torque maintenance in N.cm by a digital torque meter and analyzing the microgaps in µm in the implant-abutment connection by microscopy. The P1P group showed a significant reduction in post-cycling removal torque 10.57 (±3.63) compared to precycling torque 31.63 (±0.80) and initial removal torque 26.48 (±1.60). The P2P-B group showed significant increase in post-cycling removal torque 41.00 (±8.64), compared to pre-cycling torque 31.10 (±0.62) and initial removal torque 30.12 (±2.08), its top the P2P-P showed significant decrease in post-cycling removal torque 14.85 (±2.06), compared to pre-cycling torque 21.06 (±0.50), but showed no significant difference with the initial removal torque 15.51 (±1.18). In the microscopic evaluation, the implant-abutment connection in both groups showed reduced initial microgaps, P1P 4.71 (±2.12) and P2P-B 3.95 (±2.02), which had significant reduction after cycling, P1P 0.006 (±0.001) and P2P-B 0.005 (±0.001). The P2P showed superior biomechanical behavior than the P1P abutment in post-cycling torque values at the various comparative times, supporting its use for single crowns. The connection interface of both abutments exhibited reduced microgaps under microscopy, which were practically eliminated with the coupling produced by mechanical cycling. (AU)

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This study aimed to evaluate possible changes in final retention after nine sequences of insertion and removal (SIR) of a frictional Morse taper implant/abutment system, evaluating the force required for dissociating this set between sequences, and verifying possible deformations in the implant heads. Ten implants, 13 mm long and 3.3 mm in diameter, were coupled to a universal mechanical testing machine. Ten anti-rotational abutments, 13 mm long and 3.5 mm in diameter, were connected to the implants parallel to the long axis, using an instrument called beat-connection, and subjected to tensile tests and SEM analysis. The results were analyzed using the Kruskal-Wallis test with Dunn's post-test, and the significance level was set at 5 %. There was no statistically significant difference in final retention among the nine SIRs evaluated. The force needed to uncouple the abutment from the implant increased as SIRs were performed on all ten implants, and an increase of 29.03 % was observed in the ninth SIR compared to the first SIR. After SEM analysis, no significant deformations, fractures, or cracks were observed in the implant heads.

Este estudio tuvo como objetivo evaluar los posibles cambios en la retención final después de nueve secuencias de inserción y extracción (SIR) de un sistema de implante / pilar de cono de fricción Morse, evaluando la fuerza necesaria para disociar este conjunto entre secuencias y verificando posibles deformaciones en las cabezas de los implantes. Se acoplaron diez implantes, de 13 mm de largo y 3,3 mm de diámetro, a una máquina universal de ensayos mecánicos. Se conectaron a los implantes en paralelo al eje largo diez pilares antirrotacionales, de 13 mm de largo y 3,5 mm de diámetro, mediante un instrumento llamado beat-connection, y se sometieron a pruebas de tracción y análisis SEM. Los resultados se analizaron mediante la prueba de Kruskal-Wallis con la prueba posterior de Dunn, y el nivel de significancia se estableció en 5 %. No hubo diferencias estadísticamente significativas en la retención final entre los nueve SIR evaluados. La fuerza necesaria para desacoplar el pilar del implante aumentó a medida que se realizaban SIR en los diez implantes, y se observó un aumento del 29,03 % en el noveno SIR en comparación con el primer SIR. Después del análisis SEM, no se observaron deformaciones, fracturas o grietas significativas en las cabezas de los implantes.

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INTRODUCTION: Defects in the maxillary anterior teeth are delicate and difficult to solve because of the esthetic, functional, and psychological impairment that may arise if the rehabilitation treatment does not return the damaged tissues to the naturalness. Esthetic predictability and reduced surgical interventions are some great reasons to simplify dental treatments. During the presurgical evaluation, the clinician should review the implant esthetic risk profile, considering the patient's smile line, the esthetic demands, the hard and soft tissue thickness and width, and the gingival biotype. Thus, achieving long-term esthetic results initiates with a detailed case planning before surgical intervention. CASE PRESENTATION: The present report described a complex esthetic clinical case involving teeth and dental implant related to a high smile line. The clinical case was solved through immediate implant placement and immediate loading using a personalized prosthetic abutment and finalized with the installation of metal-free prosthetic restorations. CONCLUSION: The use of a personalized prosthetic abutment helped to achieve a better emergence of the prosthesis under the periodontal tissues. Although it was a challenging esthetic case, especially because of the high smile line, the result was a natural smile while the adjacent soft tissues maintained their esthetics and health.

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Prosthetic intermediaries in oral implantology are attachments that allow connection between the implant and the prosthesis itself. Although this rehabilitation has a high success rate; the selection of the prosthetic abutment represents is important in implant treatment. Currently, there is a great variety of intermediate abutments, corresponding to various techniques and materials. Prosthetic intermediaries can be classified according to the type of connection, their retention to the prosthesis, their axial relationship with the implant body, the manufacturing material and type of manufacture, or whether rehabilitation is single or multiple. This scenario can lead to doubts as to the selection of the ideal implant attachment in each case in order to achieve satisfactory rehabilitation, as well as functional and aesthetic requirements and the preservation of biological principles. Indeed, oral implantology has revolutionized dentistry and will continue to expand the range of possibilities; therefore, it is important to classify the prosthetic options available. The present literature review aims to demonstrate the different alternatives and options available for the intermediate abutments most used in implant prostheses.

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Different techniques are available to manufacture polymer-infiltrated ceramic restorations cemented on a chairside titanium base. To compare the influence of these techniques in the mechanical response, 75 implant-supported crowns were divided in three groups: CME (crown cemented on a mesostructure), a two-piece prosthetic solution consisting of a crown and hybrid abutment; MC (monolithic crown), a one-piece prosthetic solution consisting of a crown; and MP (monolithic crown with perforation), a one-piece prosthetic solution consisting of a crown with a screw access hole. All specimens were stepwise fatigued (50 N in each 20,000 cycles until 1200 N and 350,000 cycles). The failed crowns were inspected under scanning electron microscopy. The finite element method was applied to analyze mechanical behavior under 300 N axial load. Log-Rank (p = 0.17) and Wilcoxon (p = 0.11) tests revealed similar survival probability at 300 and 900 N. Higher stress concentration was observed in the crowns' emergence profiles. The MP and CME techniques showed similar survival and can be applied to manufacture an implant-supported crown. In all groups, the stress concentration associated with fractographic analysis suggests that the region of the emergence profile should always be evaluated due to the high prevalence of failures in this area.

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The objective of this study was to perform a quality analysis of systematic reviews with meta-analyses that focused on the comparison of platform-switching (implant-abutment mismatching) and platform-matched (PM) implants. The assessment of multiple systematic reviews (AMSTAR) and Glenny (Checklist) Scales were used to qualify the studies. PubMed, Scientific Electronic Library Online (SciELO), Web of Science (formerly ISI Web of Knowledge), and Cochrane databases were searched, by topic, for systematic reviews on dental implants with switching platforms. A total of 8 systematic reviews, including 7 studies with meta-analyses, were selected. The AMSTAR scale indicated a high (n = 6) to moderate (n = 2) score for the included studies. The quantitative analysis indicated that platform-switching implants preserved more bone tissue when compared with platform-matched implants (6 meta-analyses; P < .001, smaller mean difference: -0.29 mm, 95% CI: -0.38, -0.19 and greater mean difference: -0.49 mm, 95% CI: -0.73, -0.26). Quantitative analysis based on 7 systematic reviews with meta-analysis indicated positive peri-implant bone preservation for implants restored with an implant-abutment mismatching (PSW). Further, there is evidence to improve the design of current systematic reviews. Future systematic reviews in this thematic area should consider searches in gray literature and different databases and include only randomized controlled clinical studies.

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Introduction: The cantilever length of implant-supported fixed prosthesis metal structure has been considered an important factor to transfer occlusion forces to the dental implant. Objective: This study evaluated the influence of different extensions of cantilevers of Branemark protocol implant prosthesis when submitted to mechanical thermocycling by screw loosening evaluation. Material and method: The groups G10 (n = 5), G15 (n = 5) and G20 (n = 5) were formed according to the distance in millimeters between the force application site in the cantilever and the center of the last implant. All metal structures (n = 15) were submitted to a 120 N cyclic vertical load in a chewing simulation machine (MSM-Elquip, São Carlos-SP, Brazil) under controlled temperature and moisture conditions. Two hundred and fifty thousand mechanical cycles were performed with a frequency of 2 Hz that simulates a masticatory activity similar to 3 months. To compare the data obtained regarding the loosening of the metal structure screws, implant position and sites of load application, the analysis of variance with two factors and the Tukey test were performed. Result: Statistical analysis showed that the G10 group presented greater torque loss, statistically different from G15 (p = 0.001) and G20 (p = 0.002), and there was no significant difference between groups G15 and G20. Conclusion: It can be concluded from the results that all the screws presented torque loss after simulation of 3 month masticatory activity, suggesting the need for periodical evaluation to prevent failures in the treatment.

Introdução: O comprimento do cantilever da infraestrutura de prótese implanto-suportada tem sido considerado um importante fator de transferência de força de oclusão para o implante dentário. Objetivo: Esse trabalho avaliou a influência das diferentes extensões do cantilever da prótese sobre implantes tipo protocolo de Branemark submetidas à termociclagem mecânica pela avaliação dos afrouxamentos dos parafusos de fixação. Material e método: Os grupos G10 (n=5), G15 (n=5) e G20 (n=5) foram formados de acordo com a distância, em milímetros, entre o local de aplicação de força no cantilever e o centro do último implante. Todas as barras (n=15) foram submetidas a carga vertical cíclica de 120 N em uma máquina de simulação de mastigação (MSM-Elquip, São Carlos/SP, Brasil), em condições de temperatura e umidade controladas. Foram realizados 250 mil ciclos mecânicos com frequência de 2 Hz que simulou uma atividade mastigatória correspondente a 3 meses. Para comparar os dados obtidos quanto à soltura dos parafusos da barra, a posição dos implantes e os locais de aplicação de carga, foi realizada a análise de variância com dois fatores e o teste de Tukey. Resultado: A análise estatística mostrou que o grupo G10 apresentou maior perda de torque, diferente estatisticamente de G15 (p=0,001) e G20 (p=0,002) e que não houve diferença significante entre os grupos G15 e G20. Conclusão: Pode-se concluir que todos os parafusos apresentaram perda de torque após o ensaio simulando uma atividade mastigatória de 3 meses, sugerindo a necessidade de avaliação clínica periódica afim de prevenir fracasso no tratamento.

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PURPOSE: This study evaluated the stress distribution in different cement-retained implant-supported prostheses with a hybrid abutment. MATERIALS AND METHODS: Two factors were evaluated: restorative material for the crown and hybrid abutment - zirconia, lithium disilicate and hybrid ceramic, yielding 9 combinations. For finite element analysis, a monolithic crown cemented on a hybrid abutment was modeled and cemented on a titanium base (Ti base). An oblique load (45°, 300 N) was applied to the fossa bottom and system fixation occurred on the bone's base. RESULTS: Each structure was evaluated separately to find the possible weaknesses in geometry and failure criteria. In this context, results demonstrated a significant decrease of maximum principal and von-Mises stresses concentration when crowns with high elastic modulus are cemented onto a hybrid abutment with lower elastic modulus. CONCLUSIONS: Considering this theoretical study for a Morse taper implant, the association of a rigid crown with a more resilient hybrid abutment reduces the tensile stress concentration in the restoration cervical region.

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BACKGROUND: This experimental study assessed reverse torque of indexed and nonindexed (NI) abutments in Morse Taper (MT) implants in a mechanical fatigue test. MATERIALS AND METHODS: In this experimental study It was used 37 implants MT and over them installed Pilar Flex abutments (4.8 mm × 6 mm × 1.5 mm). The groups were as follows: Group A used 19 MT implants with a NI Pilar Flex abutment loaded with 32 N/cm and Group B used 18 MT implants with an indexed (IN) Pilar Flex abutment loaded with 20 N/cm. The abutments were tested according to ISO standard 14801/2007. The specimens were installed at 30° from the axial axis and underwent a 133 N load, 4 Hz frequency, and 1,000,000 cycles. Once the test was completed, the reverse torque was provided by an electronic torque meter. Data were submitted to statistical analysis using the t-test for independent samples and paired t-test. The significance level was considered P < 0.05. RESULTS: Results obtained showed that the indexed Pilar Flex abutment had a percentage of torque loss from the initial torque of 49% and the NI Pilar Flex abutment lost 14%. Paired Student's t-tests revealed that for both NI (P < 0.001) and indexed (P < 0.001) abutments, the counter torque values were significantly lower than those applied at the initial torque. CONCLUSION: According on the methodology used, the NI Pilar Flex abutment was more effective regarding the reverse torque in single-unit implant prostheses versus the indexed Pilar Flex abutment. A greater loosening in the indexed Pilar Flex abutment retaining screw was noted in the reverse torque test, and the Pilar Flex abutment failed to show good outcomes related to the cold welding effect.