Influence of carbonated acid beverage on fracture resistance and marginal gap formation in different restorative approaches to non-carious cervical lesions.

OBJECTIVE: This study is to evaluate fracture resistance, failure mode, and gap formation at the restorative interface of unrestored or restored non-carious cervical lesions (NCCLs) submitted to a short-term erosive environment. MATERIALS AND METHODS: Artificial NCCLs were produced in vitro in bovine incisors, and were randomly divided into four restorative resins groups (n = 22): nanohybrid-NR; bulk-fill-BR; flow with a nanohybrid layer-FNR; bulk-fill with a nanohybrid layer-BNR; and a group unrestored-UR (n = 16). Half of the specimens were submitted to an erosive challenge (per 5 min, 3 × a day for 7 days, before and after restoration), and the other half, was immersed in artificial saliva. After, all teeth undergone thermal (5 ºC, 37 ºC, and 55 ºC, 3600 cycles) and mechanical (50 N, 2 Hz, 300,000 cycles) aging. Eighty teeth were subjected to compressive loading, and resistance and failures were analyzed, while 24 teeth were evaluated for gaps by microcomputed tomography. Statistical tests were performed (p < 0.05). RESULTS: The restorative approaches affected fracture resistance (η2p = 0.14, p = 0.023), and gap formation (η2 = 0.18, p = 0.012) and so did the immersion medium (fracture η2p = 0.09, p = 0.008; gap η2 = 0.09, p = 0.017). BNR showed the highest resistance, while UR the lowest. FNR showed the highest gaps in both immersion media. Neither the resin groups nor the immersion media were associated with failure mode. CONCLUSIONS: The erosive immersion medium based in acid beverages has been shown to affect NCCLs with or without restoration, but when Bulk-Fill resin is covered by nanohybrid resin, the performance is good. CLINICAL RELEVANCE: Erosion negatively affects restorations, but unrestored NCCL shows worse biomechanical performance in stress-bearing situations.

Relationship between normative and self-perceived criteria for orthodontic treatment need and satisfaction with esthetics and mastication in adolescents.

INTRODUCTION: Orthodontic treatments are performed to improve esthetics and masticatory functions. In general, clinical criteria are used to recommend such treatments without considering the opinion of the patient. This study aimed to evaluate the relationship between technically defined orthodontic need (normative criteria) and the need for treatment perceived by adolescent patients. METHODS: A total of 215 students aged between 15 and 19 years were selected and asked to respond to a questionnaire concerning their perception of need for orthodontic treatment and their satisfaction with their own esthetics and mastication. One trained and calibrated examiner obtained normative data using the Dental Aesthetic Index (DAI) on the need for orthodontic treatment of these students. RESULTS: Associations were found between the DAI score and the patient's perception of need for orthodontic treatment (P <0.001), satisfaction with esthetics (P = 0.003), and satisfaction with mastication (P = 0.047). When occlusal characteristics were analyzed separately, associations between several normative and perceived needs, as well as for satisfaction with esthetics, were found. Satisfaction with mastication analysis was only found to be associated with open bite malocclusion (P = 0.003). CONCLUSIONS: The DAI revealed a consistent opinion in adolescents to link their perceived malocclusion-related conditions to esthetics.

Angle Class II, Division 2 Malocclusion and Association with Late Eruption

Objective: To verify the dental age of individuals with Angle Class II, division 2 malocclusion. Material and Methods: The sample consisted of 200 panoramic radiographs of schoolchildren from the city of Fortaleza in the state of Ceará, in the northeast of Brazil. These radiographs were divided into two groups (N=100): a Control group comprising radiographs of patients with normal occlusion and a CIID2 group comprising radiographs of patients with an Angle Class II, division 2 malocclusion. The Demirjian method was used to identify dental age. All the radiographs were evaluated by a sole duly trained and calibrated technician. The Kappa coefficient for inter-annotator agreement was 0.98 based on the criteria of eruption stage of each tooth. Statistical analysis was performed using the Chi-squared test, Student's t-test and the Mann-Whitney test, with a level of significance of 5%. Results: There was a significant statistical difference between the dental ages of the groups tested. The CIID2 group had a lower dental age than the control group, signifying late eruption in patients with an Angle Class II, division 2 malocclusion. Conclusion: Patients with an Angle Class II, division 2 malocclusion had a lower dental age than patients with normal occlusion, suggesting that orthodontic treatment should be delayed. The first molars, second pre-molars and canines suffered late eruption.

Microleakage at Different Implant-Abutment Connections Under Unloaded and Loaded Conditions.

PURPOSE: This study evaluated the microleakage at different implant-abutment (I-A) connections under unloaded and loaded conditions. MATERIALS AND METHODS: Forty implants, specially designed with an opening at the apex, were grouped according to the I-A and screw device: external hexagon implants with titanium (EH) or EH diamond-like carbon screws fixing the abutment; internal hexagon implants with titanium screws (IH); and Morse taper implants with solid (MT) or MT passing screws (MTps) abutments. The implants were fixed in a 2-compartment device, and toluidine blue solution (1.0 mg/mL) was placed at the I-A interface (upper compartment). The lower compartment was filled with purified water. Four implants of each group were loaded (50 N, 1.2 Hz) and after 50,000, 100,000, 200,000, and 300,000 cycles, aliquots were collected from the lower compartment for absorbance reading. Data were analyzed using analysis of variance for repeated measurements and Tukey (α = 0.05). RESULTS: Although microleakage increased over time in most of the groups, MTps group showed lower values when loaded (P < 0.05). The DLC on the EH screw did not prevent microleakage (P < 0.05). CONCLUSION: It can be concluded that MT connection is more effective to prevent microleakage.

Bacterial Adhesion and Surface Roughness for Different Clinical Techniques for Acrylic Polymethyl Methacrylate.

This study sought to assess the effect of different surface finishing and polishing protocols on the surface roughness and bacterial adhesion (S. sanguinis) to polymethyl methacrylates (PMMA). Fifty specimens were divided into 5 groups (n = 10) according to their fabrication method and surface finishing protocol: LP (3 : 1 ratio and laboratory polishing), NF (Nealon technique and finishing), NP (Nealon technique and manual polishing), MF (3 : 1 ratio and manual finishing), and MP (3 : 1 ratio and manual polishing). For each group, five specimens were submitted to bacterial adhesion tests and analyzed by scanning electron microscopy (SEM). Two additional specimens were subjected to surface topography analysis by SEM and the remaining three specimens were subjected to surface roughness measurements. Data were compared by one-way ANOVA. The mean bacterial counts were as follows: NF, 19.6 ± 3.05; MP, 5.36 ± 2.08; NP, 4.96 ± 1.93; MF, 7.36 ± 2.45; and LP, 1.56 ± 0.62 (CFU). The mean surface roughness values were as follows: NF, 3.23 ± 0.15; MP, 0.52 ± 0.05; NP, 0.60 ± 0.08; MF, 2.69 ± 0.12; and LP, 0.07 ± 0.02 (µm). A reduction in the surface roughness was observed to be directly related to a decrease in bacterial adhesion. It was verified that the laboratory processing of PMMA might decrease the surface roughness and consequently the adhesion of S. sanguinis to this material.

Fracture Resistance of Internal Conical and External Hexagon: Regular and Narrow Implant-Abutment Assemblies.

PURPOSE: The aim of this study was to compare the maximum load on the elastic limit of internal conical (IC) implants with regular external hexagon (REH) and narrow external hexagon (NEH) implants. MATERIALS AND METHODS: Thirty cylindrical implants were divided in 3 groups (n = 10): REH (3.75 mm); NEH (3.3 mm); IC (3.5 mm). The implants were evaluated by means of cantilever bending loads using a mechanical testing machine. A strain qualitative analysis and the corresponding angles were analyzed. Using single factor analysis of variance with Tukey Test and Friedman Test (P < 0.05) the statistical analysis for data were performed. RESULTS: REH (294.37 N) and IC (294.37 N) groups presented statistically greater Fle than NEH (189.16 N). Regarding to the strain, there were no significant differences among groups. However, there were a greater number of fissures and more fractures present on NEH group. CONCLUSION: The IC implant with smaller diameter did not result in reduction of elastic limit when compared with the REH implants. Nevertheless, the reduction of 0.45 mm of the hexagonal connection implant's diameter has significantly diminished the elastic limit.

Passivity of conventional and CAD/CAM fabricated implant frameworks.

The objective of this research was to evaluate the passivity by measuring the passive fit and strain development of frameworks screwed on abutments, made by CAD/CAM technology, and to compare these parts with samples manufactured by conventional casting. Using CAD/CAM technology, four samples were made from zirconia (Zircad) and four samples were manufactured from cobalt-chrome (CoCrcad). The control groups were four specimens of cobalt-chrome, made by one-piece casting (CoCrci), with a total of 12 frameworks. To evaluate the passive fit, the vertical misfit at the abutment-framework interface was measured with scanning electron microscopy (250×) when only one screw was tightened. The mean strain in these frameworks was analyzed by photoelasticity test. A significant difference in the passive fit was observed between the control and sample groups. CoCrcad exhibited the best value of passive fit (48.76±13.45 µm) and CoCrci the worst (187.55±103.63 µm); Zircad presented an intermediate value (103.81±43.15 µm). When compared to the other groups, CoCrci showed the highest average stress around the implants (17.19±7.22 kPa). It was concluded that CAD/CAM-fabricated frameworks exhibited better passivity compared with conventionally fabricated frameworks. CAD/CAM-fabricated Co-Cr frameworks may exhibit better passive fit compared with CAD/CAM-fabricated zirconia frameworks. Even so, similar levels of stress were achieved for CAD/CAM-fabricated frameworks.

Passivity of Conventional and CAD/CAM Fabricated Implant Frameworks

The objective of this research was to evaluate the passivity by measuring the passive fit and strain development of frameworks screwed on abutments, made by CAD/CAM technology, and to compare these parts with samples manufactured by conventional casting. Using CAD/CAM technology, four samples were made from zirconia (Zircad) and four samples were manufactured from cobalt-chrome (CoCrcad). The control groups were four specimens of cobalt-chrome, made by one-piece casting (CoCrci), with a total of 12 frameworks. To evaluate the passive fit, the vertical misfit at the abutment-framework interface was measured with scanning electron microscopy (250×) when only one screw was tightened. The mean strain in these frameworks was analyzed by photoelasticity test. A significant difference in the passive fit was observed between the control and sample groups. CoCrcad exhibited the best value of passive fit (48.76±13.45 µm) and CoCrci the worst (187.55±103.63 µm); Zircad presented an intermediate value (103.81±43.15 µm). When compared to the other groups, CoCrci showed the highest average stress around the implants (17.19±7.22 kPa). It was concluded that CAD/CAM-fabricated frameworks exhibited better passivity compared with conventionally fabricated frameworks. CAD/CAM-fabricated Co-Cr frameworks may exhibit better passive fit compared with CAD/CAM-fabricated zirconia frameworks. Even so, similar levels of stress were achieved for CAD/CAM-fabricated frameworks.

O objetivo desta pesquisa foi avaliar a passividade através da medição da tensão induzida e adaptação passiva em infra-estruturas parafusadas sobre pilares, confeccionadas por tecnologia CAD/CAM, e comparar estas amostras com peças fabricadas por fundição convencional. Usando a tecnologia de CAD/CAM, quatro amostras foram feitas em zircônia (ZirCAD) e quatro amostras foram fabricados em cobalto-cromo (CoCrcad). Os grupos controle foram quatro espécimes de cobalto-cromo, feitos por fundição em monobloco (CoCrci), totalizando 12 infra-estruturas. Para avaliar a adaptação passiva, a diferença vertical entre a infraestrutura e o pilar protético foi medido em microscopia eletrônica de varredura (250 ×) quando apenas um parafuso foi apertado. A tensão média nestas infraestruturas foi analisada através do teste de fotoelasticidade. Foi observada uma diferença significativa na passividade entre os grupos controle e demais amostras. CoCrcad exibiu melhor valor de adaptação passiva (48,76±13,45 mm) e CoCrci o pior (187,55±103,63 mm), Zircad apresentou um valor intermediário (103,81±43,15 µm). Quando comparado com os outros grupos, CoCrci apresentou a maior tensão média ao redor dos implantes (17,19±7,22 kPa). Concluiu-se que a tecnologia CAD/CAM exibiu maior passividade em comparação com as infraestruturas confeccionadas pela técnica convencional. Infraestruturas confeccionadas em Co-Cr através do CAD/CAM apresentaram maior adaptação passiva em comparação com as amostras confeccionadas por CAD/CAM em zircônia. Entretanto, níveis de estresse similares foram obtidos para as estruturas fabricadas por CAD/CAM.

Influence of crown-to-implant ratio on stress around single short-wide implants: a photoelastic stress analysis.

PURPOSE: The aim of this study was to evaluate the photoelastic fringe patterns around two short-wide implants supporting single crowns with different crown-to-implant (C/I) ratios. MATERIALS AND METHODS: External hexagon (EH) cylindrical implants (5 × 7 mm) or Morse Taper (MT) conical implants (5 × 6 mm) were embedded individually into photoelastic resin blocks. Each implant received a single metal-ceramic crown, with a C/I ratio of 1:1 or 2:1 (n = 10). Each set was positioned in a polariscope and submitted to a 0.5 kgf compressive load, applied axially or obliquely (30°). The polariscope images were digitally recorded, and based on isoclinal and isochromatic fringes, the shear stress was calculated at 5 predetermined points around each implant. Data were analyzed by two-way ANOVA (α = 0.05). RESULTS: Under axial loading, the stress was concentrated at the crestal region, and there were no differences between C/I ratio or implant types. In contrast, under oblique loading, EH implants showed lower stress values than the MT group and the 2:1 C/I ratio showed higher stress concentration for both implant types (p < 0.05). Moreover, MT implants showed stress distribution through a higher area than the EH implant did, with a tendency to direct the stress toward the implant's apex under oblique loading. CONCLUSION: MT conical short-wide implants showed higher stress values that were distributed through a higher area directed to the implant apex. The C/I ratio influences the stress distribution only under oblique loading.

Photoelastic stress analysis of mandibular fixed prostheses supported by 3 dental implants.

PURPOSE: To observe the photoelastic stress patterns generated around implants in relation to variations in the diameter and total number of implants supporting fixed complete-arch mandibular frameworks. MATERIALS AND METHODS: Three different implant configurations were analyzed (n = 3): 5 standard implants with diameters of 3.75 mm (C), 3 standard implants with diameters of 3.75 mm (3S), and 3 wide implants with diameters of 5.0 mm (3W). The samples were subjected to a vertical compressive load (1.33 kgf) applied at the end of the distal cantilever of the framework. The shear stresses were calculated around the implants, and the data were analyzed using one-way analysis of variance. RESULTS: The implants nearest to the loading showed higher stress values regardless of the group. The C group showed lower shear stress when compared with the other groups (P = 0.001). No significant difference was observed between the 3W and 3S groups (P = 0.785). CONCLUSION: A reduction in the number of implants, regardless of the implant diameter, showed higher stress concentration around the implants. Five-implant configuration showed lower stress concentration and seems to be more biomechanically predictable.

Stress analysis of different configurations of 3 implants to support a fixed prosthesis in an edentulous jaw.

This study's aim was to evaluate the stress distribution in a mandibular implant-supported prosthesis and peri-implant bone considering implant quantity, diameter and position using linear 3-D finite element analysis. Models of an anterior jaw comprised 4 groups according to implant quantity, diameter, and position: control group C, 5 regular implants; R, 3 regular implants; W, 3 wide implants; and DTR, 3 regular implants with the distal ones tilted 30° distally. The cantilever was loaded with an axial load of 50 N. Data was evaluated using von Mises stress on implants and maximum principal stress and microstrain on the bone. The W group showed the lowest value of maximum principal stress in peri-implant bone of the loaded side (4.64 MPa) when compared to C (5.27 MPa), DTR (5.94 MPa), and R (11.12 MPa). Lower stress values in the loaded implants were observed in the experimental groups when compared to the C group. However, the unloaded implants presented opposite results. All the screws of the W group presented lower stress values when compared to the C group. However, the R and DTR groups presented an increase in stress values with the exception of the loaded screw. A reduction in the number of implants associated with wider implants reduced the stress in the bone and prosthetic components.

Bacterial microleakage at the implant-abutment interface in Morse taper implants

AIM: To evaluate the microleakage at the implant-abutment (I-A) interface of Morse tapered implants inoculated with different volumes of bacterial suspension. METHODS: Morse tapered I-A sets were selected and divided in two groups depending on the type of abutment: passing screw (PS) and solid (S), and then subdivided into four subgroups (n=6) according to the suspension volume: PS1: 0.1 µL; PS3: 0.3 µL; PS5: 0.5 µL; PS7: 0.7 µL; S1: 0.1 µL; S3: 0.>3 µL; S5: 0.5 µL and S7: 0.7 µL. A control test was performed to verify the presence of external contamination during the inoculation and the implants were incubated for microbiological analysis. The microleakage was evaluated every 24 h for 7 days by the clarity of solution. After this period, the implants were disassembled for confirmation of bacterial viability. RESULTS: All the specimens with 0.7 µL and one sample of S5 presented turbidity in the control test indicating external contamination, and were excluded from the study. After 7 days of observation, none of the specimens presented positive results for microleakage and the bacterial viability was confirmed in all specimens. The 0.1 µL and 0.3 µL volumes did not present bacterial microleakage, meaning that these volumes may be inadequate for analysis. CONCLUSIONS: None of the sets evaluated showed bacterial microleakage at the I-A interface and the volume of 0.7 µL exceeded the internal capacity of the implants...

Stress analysis of different configurations of 3 implants to support a fixed prosthesis in an edentulous jaw

This study's aims was to evaluate the stress distribution in a mandibular implant-supported prosthesis and peri-implant bone considering implant quantity, diameter and position using linear 3-D finite element analysis. Models of an anterior jaw comprised 4 groups according to implant quantity, diameter, and position: control group C, 5 regular implants; R, 3 regular implants; W, 3 wide implants; and DTR, 3 regular implants with the distal ones tilted 30º distally. The cantilever was loaded with an axial load of 50 N. Data was evaluated using von Mises stress on implants and maximum principal stress and microstrain on the bone. The W group showed the lowest value of maximum principal stress in peri-implant bone of the loaded side (4.64 MPa) when compared to C (5.27 MPa), DTR (5.94 MPa), and R (11.12 MPa). Lower stress values in the loaded implants were observed in the experimental groups when compared to the C group. However, the unloaded implants presented opposite results. All the screws of the W group presented lower stress values when compared to the C group. However, the R and DTR groups presented an increase in stress values with the exception of the loaded screw. A reduction in the number of implants associated with wider implants reduced the stress in the bone and prosthetic components.

Comparison of implant-abutment interface misfits after casting and soldering procedures.

The aim of this study was to compare vertical and horizontal adjustments of castable abutments after conducting casting and soldering procedures. Twelve external hexagonal implants (3.75 × 10 mm) and their UCLA abutments were divided according their manufacturer and abutment type: PUN (plastic UCLA, Neodent), PUC (plastic UCLA, Conexão), PU3i (plastic UCLA, Biomet 3i), and PUTN (plastic UCLA with Tilite milled base, Neodent). Three infrastructures of a fixed partial implant-supported bridge with 3 elements were produced for each group. The measurements of vertical (VM) and horizontal (HM) misfits were obtained via scanning electron microscopy after completion of casting and soldering. The corresponding values were determined to be biomechanically acceptable to the system, and the results were rated as a percentage. Statistical analysis establishes differences between groups by chi-square after procedures, and McNeman's test was applied to analyze the influence of soldering over casting (α ≤ .05). For the values of VM and HM, respectively, when the casting process was complete, it was observed that 83.25% and 100% (PUTN), 33.3% and 27.75% (PUN), 33.3% and 88.8% (PUC), 33.3% and 94.35% (PU3i) represented acceptable values. After completing the requisite soldering, acceptable values were 50% and 94.35% (PUTN), 16.6% and 77.7% (PUN), 38.55% and 77.7% (PUC), and 27.75% and 94.35% (PU3i). Within the limitations of this study, it can be concluded that the premachined abutments presented more acceptable VM values. The HM values were within acceptable limits before and after the soldering procedure for most groups. Further, the soldering procedure resulted in an increase of VM in all groups.

Comparison of methods to evaluate implant-abutment interface

Aim: To compare two main methods of two-dimensional measurement of fit at the implant prosthodontic interface, testing the hypothesis that optical microscopy (OM) can reliably and efficiently scanning electronic microscopy (SEM). Methods: Four frameworks with four titanium abutments joined with titanium bars were used. The implant-abutment interfaces were examined by three different methods, forming 3 groups: analysis by OM (40x), and analysis by SEM at 300x and 500x. Readings were taken at the mesial and distal proximal surfaces on the horizontal and vertical axes of each implant (n=32). One-way ANOVA with a significance level of 5% was used for statistical analysis. Results: Neither the horizontal fit nor vertical fit values of the 3 groups presented statistically significant differences (p=0.410 and p=0.543). Conclusions: OM was found to be an accurate two-dimensional method for abutment-framework or implant-abutment interface measurements, with lower costs than SEM. SEM micrographs at 500x presented technical difficulties for the readings that might produce different results.

Photoelastic stress analysis of different wide implant/abutment interfaces under oblique loading.

PURPOSE: There is a variety of implant/abutment (I/A) junctions for the connection of implant-supported prostheses. The aim of this work was to compare the shear stress distribution in three types of I/A interfaces after application of oblique loading on the abutments, simulating loading on an anterior tooth. MATERIALS AND METHODS: Similar wide unthreaded and cylindric implants (13.0 mm in length and 5.0 mm in diameter) and abutments were fabricated and embedded in photoelastic acrylic resin. The I/A assemblies featured three different I/A interfaces: external hex, internal hex, and internal taper. The samples were submitted to a compressive load of 0.6 kgf, which was applied to the abutment at an angle of 135 degrees. The maximum shear stresses were determined and observed at 21 points around the implants in the photoelastic models (n = 4). Graphics describing the maximum shear stress (y-axis) and the analyzed points (x-axis) were created, and the curve areas were calculated. The Kruskal-Wallis test was applied to analyze the results (P < .05). RESULTS: There were no statistically significant differences between the groups (P = .058). CONCLUSION: All of the wide-diameter I/A junctions presented similar behavior under oblique loading and appeared to be suitable to support prostheses that could receive this type of loading.

Gingival conditioning in an implant-supported prosthesis: a clinical report.

The loss of gingival volume is a major challenge for dental surgeons with implant-supported fixed prosthesis manufactures, particularly from an aesthetics perspective in patients with a high smile line. Gingival tissue remodeling can help in papillae formation to avoid soft tissue surgery by reestablishing the appropriate shape and gingival contour of the tissues. This improves not only the aesthetics, but also the phonetics of the patient. This paper describes a clinical case of gingival conditioning obtained with interim implant-supported fixed partial dentures via incremental addition and adjustment of acrylic resin. The purpose of the gingival conditioning was to obtain improved aesthetics. Gingival conditioning by gradual pressure application is presented as an easy, non-traumatic technique that improves gingival aesthetics.

Micro-leakage at the implant-abutment interface with different tightening torques in vitro.

OBJECTIVES: This study evaluated the microleakage at the implant/abutment interface of external hexagon (eH) implants and abutments with different amounts of bacteria and tightening torques. MATERIAL AND METHODS: A bacterial suspension was prepared to inoculate the implants. The first phase of this study used nine EH implants and abutments that were divided into three groups with different amounts of bacterial suspension (n=3): V0.5: 0.5 µL; V1.0: 1.0 µL e V1.5: 1.5 µL, and tightened to the manufacturer's recommended torque. The second phase of this experiment used 27 assemblies that were similar to those used in the first phase. These samples were inoculated with 0.5 µL of bacterial suspension and divided into three groups (n=9). T10: 10 Ncm; T20: 20 Ncm and T32: 32 Ncm. The samples were evaluated according to the turbidity of the broth every 24 hours for 14 days, and the bacteria viability was tested after that period. The statistical evaluation was conducted by Kruskal-Wallis testing (p<.05). RESULTS: During the first phase, groups V1.0 and V1.5 was presented with bacterial contamination in all samples after 24 h. During the second phase, two samples from group T10 and one from T20 presented positive results for bacterial contamination. Different amounts of bacterial solution led to overflow and contamination during the first 24 h of the experiment. The tightening torques did not statistically affect the microleakage in the assemblies. However, the group that was tightened to 32 Ncm torque did not show any bacterial contamination. CONCLUSION: After 14 days of experimentation, the bacteria were proven to remain viable inside the implant internal cavity.

Micro-leakage at the implant-abutment interface with different tightening torques in vitro

OBJECTIVES: This study evaluated the microleakage at the implant/abutment interface of external hexagon (eH) implants and abutments with different amounts of bacteria and tightening torques. MATERIAL AND METHODS: A bacterial suspension was prepared to inoculate the implants. The first phase of this study used nine EH implants and abutments that were divided into three groups with different amounts of bacterial suspension (n=3): V0.5: 0.5 µL; V1.0: 1.0 µL e V1.5: 1.5 µL, and tightened to the manufacturer's recommended torque. The second phase of this experiment used 27 assemblies that were similar to those used in the first phase. These samples were inoculated with 0.5 µL of bacterial suspension and divided into three groups (n=9). T10: 10 Ncm; T20: 20 Ncm and T32: 32 Ncm. The samples were evaluated according to the turbidity of the broth every 24 hours for 14 days, and the bacteria viability was tested after that period. The statistical evaluation was conducted by Kruskal-Wallis testing (p<.05). RESULTS: During the first phase, groups V1.0 and V1.5 was presented with bacterial contamination in all samples after 24 h. During the second phase, two samples from group T10 and one from T20 presented positive results for bacterial contamination. Different amounts of bacterial solution led to overflow and contamination during the first 24 h of the experiment. The tightening torques did not statistically affect the microleakage in the assemblies. However, the group that was tightened to 32 Ncm torque did not show any bacterial contamination. CONCLUSION: After 14 days of experimentation, the bacteria were proven to remain viable inside the implant internal cavity.