Comparative in vivo study of alloy titanium implants with two different surfaces: biomechanical and SEM analysis.

OBJECTIVES: The purpose of this study was to evaluate the biomechanical behavior of the interface formed between bone and implants with machined surfaces (MS) and those modified by Al2O3 sandblasting and acid etching (SBAS). MATERIALS AND METHODS: Before surgery, topographic characterization was performed by SEM-EDX and by mean roughness measurements. Ten Albinus rabbits received randomly 20 Ti-6Al-4V implants on its right and left tibiae, with one implant placed in each tibia. After implant insertion, the implant stability quotient (ISQ) was measured by means of resonance frequency analysis (RFA). After 3 and 6 weeks, the ISQ was again measured, followed by torque removal measurements. Analysis of variance and Tukey tests were used to analyze the data. The surface of the implants removed was evaluated by SEM-EDX. Immunohistochemical analysis of osteopontin (OPN) and osteocalcin (OC) protein was performed in bone tissue. RESULTS: The topographic characterization showed differences between the analyzed surfaces, and the mean roughness values of SBAS group were statistically higher than MS. Overall, higher statistically significant ISQ values were observed in the SBAS group compared to the MS group (p = 0.012). The intra-group comparison of ISQ values in the SBAS group showed statistically significant differences between 0 and 3 weeks (p = 0.032) and 0 and 6 weeks (p = 0.003). The torque removal measurements of group SBAS were statistically higher when compared with the torque removal measurements of group MS in the time intervals of 3 weeks (p = 0.002) and 6 weeks (p < 0.001). SEM-EDX of the implant surfaces removed in SBAS group showed greater bone tissue covering and mean values atomic in percentage of Ca, P, and O statistically superior (p < 0.05) than MS group. Immunohistochemical reactions showed intense OC immunolabeling at 6 weeks postoperative for SBAS group. CONCLUSIONS: The topographical modifications made in group SBAS allowed a better mechanical interlocking between the implant and bone tissue.

Evaluation of peri-implant condition in periodontally compromised patients.

AIMS: The aim of the study is to evaluate the profile of peri-implant tissues in periodontally compromised patients. SETTINGS AND DESIGN: In vivo - cross sectional study design. MATERIALS AND METHODS: Fifty-eight implants were evaluated, clinically and radiographically, installed in seven individuals treated by the same team of professionals, during the years 1997 and 2005 in a private dental clinic in Vitória, ES, Brazil; that time of data collection, all implants were at least 10 years of functional loading. The variables related to the dental implants evaluated were: visible Plaque Index, Gingival Bleeding Index (GBI), probing pocket depth, bleeding on probing, and bone level, to relate them to the classification of dental implants. STATISTICAL ANALYSIS USED: The Chi-square and Kruskal-Wallis test were adopted. RESULTS: The total of 58 implants were classified: 11 (18.9%) as healthy and 12 (20.7%) as clinically stable. The other 35 implants (60.4%) had some type of peri-implant inflammation, 20 of them (34.5%) were diagnosed with peri-implant mucositis and 15 (25.9%) with peri-implantitis. Among the variables studied, the results showed statistically significant differences for implant location (P = 0.001) and GBI (P = 0.03). Most of the maxillary implants (85.7%) were classified for some type of peri-implant disease. For the implants which resulted in Score 1 for GBI, most of them (75.0%) were also classified for some type of peri-implant disease. CONCLUSIONS: Dental implants placed in periodontally compromised patients may have high long-term survival rates. However, most implants were classified with some type of peri-implant inflammation.

Strain Gauge Evaluation of Transfer Impression Techniques of Multiple Implant-Supported Prosthesis.

PURPOSE: This in vitro study assessed the accuracy of multiple implant-level impression techniques (open tray and closed tray) for the fabrication of 3-unit implant prostheses with strain gauge (SG) analysis. MATERIALS AND METHODS: A polyurethane master model was designed to simulate a clinical situation. Two rigid custom trays were fabricated for the model. The impression material used was polysulfide. Transfer implant impressions were made using 2 techniques; ten tapered copings not splinted (custom closed tray) and ten square copings splinted with acrylic-resin (custom open tray). The improved stone models were allowed to set for 1 hour before being separated from the impression. The superstructures were sprued, invested, and cast with a cobalt-chromium alloy. Four SGs were bonded on the surface of each polyurethane block. RESULTS: A statistically significant difference was found between the 2 impression techniques tested (P = 0.000). This study found a significant average difference of 144.68 ± 5.53 µÎµ for open custom tray and 253.3 ± 16.7 µÎµ for closed custom tray. CONCLUSION: The custom open tray technique was the most accurate impression for multiple implants compared with closed custom tray.

Validation of a Simplified Implant-Retained Cantilever Fixed Prosthesis.

PURPOSE: To evaluate the stress and strain generated in a fixed four-element prosthesis under the application of axial and nonaxial loads using a simplified implant-supported fixed prosthesis model. MATERIALS AND METHODS: A 3-dimensional model was constructed containing 3 implants with a conventional anatomical prosthesis (G1). The second model with the same implant system received the simplified prosthesis (G2). A load of 300 N was applied at an axial point and a nonaxial point through finite element analysis software. RESULTS: The G2 group showed different values of stress concentration in the prosthesis, fixation screw, retention screw, and abutments when compared with G1. Within a limit of 10% degrees of acceptability, the stress on the implants and the bone strain were enclosed for both models of prostheses. CONCLUSION: The simplified fixed prosthesis evaluated presents biomechanical behavior similar to an anatomical prosthesis in the implants and in the surrounding bone structure.

Comparative Microstrain Study of Internal Hexagon and Plateau Design of Short Implants Under Vertical Loading.

PURPOSE: To quantify microstrain development during axial loading using strain gauge analysis for short implants, varying the type of fixture-abutment joint and thread design. MATERIALS AND METHODS: An internal hexagon implant (4 × 8 mm) and a plateau design implant (4 × 8 mm) were embedded on the center of 10 polyurethane blocks with dimensions of 190 × 30 × 12 mm. The respective abutments were screwed onto the implants. Four strain gauges (SGs) were bonded onto the surface of each block, and 4 vertical SGs were bonded onto the side of each block. Axial load of 30 kgf was applied for 10 seconds in the center of each implant. RESULTS: The data were analyzed statistically by analysis of variance for repeated measures and Tukey test (P < 0.05). The interaction between implant and region factors have been statistically significant (P = 0.0259). Tukey test revealed a difference on plateau's horizontal region. The cervical region presented higher microstrain values, when compared with the medium and apical regions of the implants. CONCLUSION: Within the purpose of the study, the type of fixture-abutment joint is a relevant factor to affect the amount of stress/strain in bone simulation. The microstrain development was concentrated on the cervical region of the implant.

Effect of Jig Design and Assessment of Stress Distribution in Testing Metal-Ceramic Adhesion.

PURPOSE: In testing adhesion using shear bond test, a combination of shear and tensile forces occur at the interface, resulting in complex stresses. The jig designs used for this kind of test show variations in published studies, complicating direct comparison between studies. This study evaluated the effect of different jig designs on metal-ceramic bond strength and assessed the stress distribution at the interface using finite element analysis (FEA). MATERIALS AND METHODS: Metal-ceramic (Metal: Ni-Cr, Wiron 99, Bego; Ceramic: Vita Omega 900, Vita) specimens (N = 36) (diameter: 4 mm, veneer thickness: 4 mm; base diameter: 5 mm, thickness: 1 mm) were fabricated and randomly divided into three groups (n = 12 per group) to be tested using one of the following jig designs: (a) chisel (CH) (ISO 11405), (b) steel strip (SS), (c) piston (PI). Metal-ceramic interfaces were loaded under shear until debonding in a universal testing machine (0.5 mm/min). Failure types were evaluated using scanning electron microscopy (SEM). FEA was used to study the stress distribution using different jigs. Metal-ceramic bond strength data (MPa) were analyzed using ANOVA and Tukey's tests (α = 0.05). RESULTS: The jig type significantly affected the bond results (p = 0.0001). PI type of jig presented the highest results (MPa) (p < 0.05) (58.2 ± 14.8), followed by CH (38.7 ± 7.6) and SS jig type (23.3 ± 4.2) (p < 0.05). Failure types were exclusively a combination of cohesive failure in the opaque ceramic and adhesive interface failure. FEA analysis indicated that the SS jig presented slightly more stress formation than with the CH jig. The PI jig presented small stress concentration with more homogeneous force distribution compared to the CH jig where the stress concentrated in the area where the force was applied. CONCLUSION: Metal-ceramic bond strength was affected by the jig design. Accordingly, the results of in vitro studies on metal-ceramic adhesion should be evaluated with caution. CLINICAL SIGNIFICANCE: When adhesion of ceramic materials to metals is evaluated in in vitro studies, it should be noted that the loading jig type affects the results. Clinical observations should report on the location and type of ceramic fractures in metal-ceramic reconstructions so that the most relevant test method can be identified.

Stress distribution on implant- supported zirconia crown of maxillary first molar: effect of oblique load on natural and antagonist tooth.

This study evaluated the stress distribution on an implant-supported zirconia crown of a mandibular first molar subjected to oblique loading by occlusal contact with the natural maxillary first molar by using the 3D finite element method. Two virtual models were made to simulate the following situations: (1) occlusion between maxillary and mandibular natural first molars; (2) occlusion between zirconia implant-supported ceramic crown on a mandibular first molar and maxillary natural first molar. The models were designed virtually in a modeling program or CAD (Computer Aided Design) (Rhinoceros). An oblique load of 100 N was uniformly applied to the zirconia framework of the crown. The results were obtained by the Von Mises criterion of stress distribution. Replacement of the mandibular tooth by an implant caused a slight increase in stress on portions of the maxillary tooth roots. The crown of the maxillary model in occlusion with natural antagonist tooth showed 12% less stress when compared with the maxillary (model in occlusion with the) implant-supported crown. The mandibular crown of the implant show 35% more stress when compared with the mandibular antagonist crown on the natural tooth. The presence of the implant to replace the mandibular tooth increased the stresses on the maxillary tooth, especially in the region of the mesial and distal buccal roots.

Microstrain around dental implants supporting fixed partial prostheses under axial and non-axial loading conditions, in vitro strain gauge analysis.

The current study used strain gauge analysis to perform an in vitro evaluation of the effect of axial and non-axial loading on implant-supported fixed partial prostheses, varying the implant placement configurations and the loading points. Three internal hexagon implants were embedded in the center of each polyurethane block with in-line and offset placements. Microunit abutments were connected to the implants using a torque of 20 N · cm, and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n = 10). Four strain gauges (SGs) were bonded onto the surfaces of the blocks, tangentially to the implants: SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments using a 10-N·cm torque, and axial and non-axial loads of 30 kg were applied at 5 predetermined points. The data obtained from the strain gauge analyses were analyzed statistically through the repeated measures analysis of variance and the Tukey test, with a conventional level of significance of P < 0.05. The results showed a statistically significant difference for the loading point (P = 0.0001), with point E (nonaxial) generating the highest microstrain (327.67 µ[Latin Small Letter Open E]) and point A (axial) generating the smallest microstrain (208.93 µ[Latin Small Letter Open E]). No statistically significant difference was found for implant placement configuration (P = 0.856). It was concluded that the offset implant placement did not reduce the magnitude of microstrain around the implants under axial and non-axial loading conditions, although loading location did influence this magnitude.

Straight and offset implant placement under axial and nonaxial loads in implant-supported prostheses: strain gauge analysis.

PURPOSE: The aim of this in vitro study was to quantify strain development during axial and nonaxial loading using strain gauge analysis for three-element implant-supported FPDs, varying the arrangement of implants: straight line (L) and offset (O). MATERIALS AND METHODS: Three Morse taper implants arranged in a straight line and three implants arranged in an offset configuration were inserted into two polyurethane blocks. Microunit abutments were screwed onto the implants, applying a 20 Ncm torque. Plastic copings were screwed onto the abutments, which received standard wax patterns cast in Co-Cr alloy (n = 10). Four strain gauges were bonded onto the surface of each block tangential to the implants. The occlusal screws of the superstructure were tightened onto microunit abutments using 10 Ncm and then axial and nonaxial loading of 30 Kg was applied for 10 seconds on the center of each implant and at 1 and 2 mm from the implants, totaling nine load application points. The microdeformations determined at the nine points were recorded by four strain gauges, and the same procedure was performed for all of the frameworks. Three loadings were made per load application point. The magnitude of microstrain on each strain gauge was recorded in units of microstrain (µÎµ). The data were analyzed statistically by two-way ANOVA and Tukey's test (p < 0.05). RESULTS: The configuration factor was statistically significant (p= 0.0004), but the load factor (p= 0.2420) and the interaction between the two factors were not significant (p= 0.5494). Tukey's test revealed differences between axial offset (µÎµ) (183.2 ± 93.64) and axial straight line (285.3 ± 61.04) and differences between nonaxial 1 mm offset (201.0 ± 50.24) and nonaxial 1 mm straight line (315.8 ± 59.28). CONCLUSION: There was evidence that offset placement is capable of reducing the strain around an implant. In addition, the type of loading, axial force or nonaxial, did not have an influence until 2 mm.

Influence of Abutment Design on Biomechanical Behavior to Support a Screw-Retained 3-Unit Fixed Partial Denture.

This study aimed to evaluate the biomechanical behavior of Morse taper implants using different abutments (CMN abutment [(CMN Group] and miniconical abutments [MC Group]), indicated to support a screw-retained 3-unit fixed partial denture. For the in vitro test, polyurethane blocks were fabricated for both groups (n = 10) and received three implants in the "offset" configuration and their respective abutments (CMN or MC) with a 3-unit fixed partial denture. Four strain gauges were bonded to the surface of each block. For the finite element analysis, 3D models of both groups were created and exported to the analysis software to perform static structural analysis. All structures were considered homogeneous, isotropic, and elastic. The contacts were considered non-linear with a friction coefficient of 0.3 between metallic structures and considered bonded between the implant and substrate. An axial load of 300 N was applied in three points (A, B, and C) for both methods. The microstrain and the maximum principal stress were considered as analysis criteria. The obtained data were submitted to the Mann-Whitney, Kruskal-Wallis, and Dunn's multiple comparison test (α = 5%). The results obtained by strain gauge showed no statistical difference (p = 0.879) between the CMN (645.3 ± 309.2 µÎµ) and MC (639.3 ± 278.8 µÎµ) and allowed the validation of computational models with a difference of 6.3% and 6.4% for the microstrains in the CMN and MC groups, respectively. Similarly, the results presented by the computational models showed no statistical difference (p = 0.932) for the CMN (605.1 ± 358.6 µÎµ) and MC (598.7 ± 357.9 µÎµ) groups. The study concluded that under favorable conditions the use of CMN or MP abutments to support a fixed partial denture can be indicated.

Screw spreading: technical considerations and case report.

The spreading system is an alternative technique to the Summers osteotome. The crest expansion technique is a less invasive procedure in which the facial wall expands after the medullary bone is compressed against the cortical wall. It improves the density of the maxillary bone, which allows for greater initial stability of implants. A specific screw instrument, the "spreader," achieved a controlled and standardized dilation of the bone horizontally. The use of spreaders to enhance the dental implant site is a highly predictable procedure.

Comparative strain gauge analysis of external and internal hexagon, Morse taper, and influence of straight and offset implant configuration.

PURPOSE: The present study was designed to analyze strain distributions caused by varying the fixture-abutment design and fixture alignment. MATERIALS AND METHODS: Three implants of external, internal hexagon, and Morse taper were embedded in the center of each polyurethane block in straight placement and offset placement. Four strain gauges (SGs) were bonded on the surface of polyurethane block, which was designated SG1 placed mesially adjacent to implant A, SG2 and SG3 were placed mesially and distally adjacent to the implant B and SG4 was placed distally adjacent to the implant C. The 30 superstructures' occlusal screws were tightened onto the Microunit abutments with a torque of 10 N cm using the manufacturers' manual torque-controlling device. RESULTS: There were statistically significant differences in prosthetic connection (P value = 0.0074 < 0.5). There were no statistically significant differences in placement configuration/alignment (P value = 0.7812 > 0.5). CONCLUSION: The results showed fundamental differences in both conditions. There was no evidence that there was any advantage to offset implant placement in reducing the strain around implants. The results also revealed that the internal hexagon and Morse taper joints did not reduce the microstrain around implants.

Influence of the dental implant number and load direction on stress distribution in a 3-unit implant-supported fixed dental prosthesis.

BACKGROUND: The choice between 2 or 3 implants to support a 3-unit implant-supported fixed dental prosthesis (FDP) still generates doubt in clinical practice. OBJECTIVES: The aim of this study was to evaluate stress distribution in 3-unit implant-supported FDPs according to the implant number and load direction. MATERIAL AND METHODS: A numerical simulation was performed to analyze stress and strain according to the implant number (2 or 3) and load direction (axial or oblique). A model of a jaw was created by means of the modeling software Rhinoceros, v. 5.0 SR8. External hexagon implants, micro-conical abutments and screws were also modeled. The final geometries were exported to the computer-aided engineering (CAE) software Ansys, v. 17.2, and all materials were considered homogeneous, isotropic and elastic. Different load directions were applied for each model (300 N) at the center of the prosthesis. RESULTS: The von Mises stress and strain values were obtained for the titanium structures and the bone, respectively. The implant number influenced the prosthesis biomechanics, with higher stress and strain concentrations when 2 implants were simulated. The oblique load also affected the mechanical response, showing higher stress and strain in comparison with the axial load, regardless of the implant number. CONCLUSIONS: It was concluded that for a 3-unit implant-supported FDP, a greater number of implants associated with axial loads can result in a better mechanical response during chewing.

Effect of Framework Type on the Biomechanical Behavior of Provisional Crowns: Strain Gauge and Finite Element Analyses.

The aim of this study was to evaluate the effects of different frameworks on the biomechanical behavior of implant-supported provisional single crowns to indicate or not the use of plastic framework as infrastructure. For finite element analysis, a hemi-jaw stone model was scanned and modeled with an external hexagon implant. A framework was screwed onto the implant and a crown was constructed over it. The set was made in triplicate according to framework type: plastic, cobalt-chromium (CoCr), and titanium. Models were exported in volumetric format to analysis software where structures were considered isotropic, linear, elastic, and homogeneous. Axial loads (100, 200, and 300 N) were applied to the fossa bottom, and the system's fixation occurred on the bone base. For strain-gauge analysis, the same hemi-jaw model was built in polyurethane and an implant was placed on it. Three crowns were made, each one with a different framework. Four strain gauges were glued around the implant to obtain microstrain values. The data were analyzed by three-way analysis of variance (ANOVA) and Tukey tests (P < .05). Finite element analysis exhibited microstrain results for bone, von Mises stress values for the implant and screw, and maximum principal stress values for the crown. For computational method, as the applied load increased, so did the stress generated. Titanium frameworks concentrated more stress in the crown and bone, while plastic ones concentrated more in the implant and screw. ANOVA showed that the higher the load value and the framework elastic modulus, the higher the generated microstrain in bone. It can be concluded that all evaluated framework types can be used in the manufacturing of provisional crowns.

Bone spreading and standardized dilation of horizontally resorbed bone: technical considerations.

The uses of a new bone spreading technique with simultaneous implant placement are discussed. The spreading system is an alternative technique to Summers' osteotome. Specific screw designs (spreader) served to laterally compress the bone to increase the cancellous density adjacent to the site. The spreader achieved a controlled and standardized dilation of horizontal bone. The advantages, material selection, and the application of this new procedure are detailed.

External hexagon and internal hexagon in straight and offset implant placement: strain gauge analysis.

PURPOSE: : The objective of this in vitro study was to quantify the strain development of external hexagon and internal hexagon implant-supported partial prostheses in straight and offset implant placement configurations. MATERIALS AND METHODS: : Three external hexagon and 3 internal hexagon implants were embedded in the center of each polyurethane block. Four strain gauges were bonded on the surface of polyurethane. The 20 superstructure occlusal screws were tightened onto the Microunit abutments with a torque of 10 Ncm using the manufacturer's manual of torque-controlling device. RESULTS: : There were statistic significant differences in hexagonal type (P = 0.0210 < 0.05). There were nostatistic significant differences in placement configuration (P = 0.7483 > 0.05). The results showed fundamental differences between both conditions. CONCLUSION: : Under the limited conditions of this study, the hexagon internal connection displayed higher values of microstrain than the hexagon external type implant placement. There was no evidence that there was an advantage of offset placement in reducing the strain around implant. There was no proof from this investigation that the straight placement generated higher microstrain than offset placement.

Bone spreader technique: a preliminary 3-year study.

The purpose of this study was to observe the clinical outcome of bone spreading and standardized dilation of horizontally resorbed bone during immediate implant placement using a "screw-type" configuration of expansion and threadformers. Fifty-three patients were included in this study, and 41 edentulous areas in anterior and posterior maxillas were treated. Sixty-eight implants were placed using an insertion torque of at least 40 Ncm. Abutments were delivered 4 to 6 months after implant placement. The overall failure percentage was 4.41% (3 failures). A retrieved analysis of 1 implant removed at 3 years after placement demonstrated bone resorption down to the level of the third thread. The bone spreader technique is different from Summers' osteotome, both in clinical use and in armamentarium. The main advantage of the crest-expanding technique is that it is a less invasive procedure; the facial wall expands after the medullary bone is compressed against the cortical wall. Within the limits of this preliminary study, the cumulative survival rate for this method of implant placement is 95.58% at 3 years. This study confirms that a bone spreader used in the maxilla shows an unusually low failure rate after 3 years.

Preservation of Dental Sockets Filled with Composite Bovine Bone. A Single-Blind Randomized Clinical Trial.

The purpose of this study was to evaluate the preservation of alveolar dimensions in human fresh extraction sockets filled with a composite bovine bone graft by means of design of single-blind randomized clinical trial. Forty participants had monoradicular teeth extracted (one teeth in each participant), and after were randomly divided into 2 groups: individuals whose fresh sockets were filled with the composite heterologous bone graft (Biomaterial Group), or with blood clot (Control Group). After extraction, the fresh sockets were measured at their greatest mesiodistal (MD) and bucco-lingual/palatal (BL/P) distance. Primary closure of the soft tissue was performed with a fibro-mucosal plug. After 120 post-operative days, the re-entry procedure was performed and the largest MD and BL/P measurements were again obtained to calculate the remodeling of the alveolar bone measured in percentage. In the biomaterial group, a percentage reduction of 1.62% and 3.29% in the MD and BL/P dimensions was observed 120 days after the extractions, whereas a reduction of 4.97% and 7.18% in the MD and BL/P dimensions occurred in the control group. There was a statistically significant difference (p<0.05) between the two groups for the bucco-palatal and mesiodistal measurements in the maxilla. In view of the results obtained, it can be concluded that composite bovine bone graft limited but did not impede alveolar bone remodeling.

Influence of different alcohol intake frequencies on alveolar bone loss in adult rats: A sem study.

BACKGROUND: Alcohol intake is associated with oral diseases and bone changes including alveolar bone loss in humans and in experimental animals. The main aim of the present study is to assess the effect of long-term alcohol intake, at different frequencies, on periodontal bone loss (PBL) in adult rats. MATERIAL AND METHODS: Thirty-six (36) rats were divided into 3 groups: Control (daily water intake, n=12), daily alcohol intake (20% ethanol, n=12), and social alcohol intake (20% ethanol twice a week, n=12). The rats were sacrificed after 90 days and their right maxillae were removed. Initially, a random portion from each group was analyzed through SEM (scanning electron microscope) to assess surface topography. Next, all pieces were dissected and stained with methylene blue 1% and photographed in stereomicroscope at 10x magnification. The PBL was assessed by measuring the distance between cement-enamel junction and alveolar bone crest. RESULTS: Results showed higher (p=0.0368) alcohol solution amount in the daily intake group than in the twice week intake one. The SEM showed qualitatively flat bone surface in the control group, the social intake group presented surface with few minor hollows, and the daily intake group evidenced increased number and diameter of wells. The comparison between groups showed higher bone loss (p<0.05) in both frequencies than in the control, but the bone loss was lower (p<0.05) in the social alcohol intake group than in the daily intake one. CONCLUSIONS: Alcohol intake may cause alveolar bone loss in periodontitis-free rats depending on the frequency. Key words:Alcohol intake, alveolar bone loss, alcohol-induced periodontitis, alcoholic rats.

The importance of correct implants positioning and masticatory load direction on a fixed prosthesis.

BACKGROUND: Through the biomechanical study of dental implants, it is possible to understand the dissipation effects of masticatory loads in different situations and prevent the longevity of osseointegration. Aims: To evaluate the microstrains generated around external hexagon implants, using axial and non-axial loads in a fixed four-element prosthesis with straight implants and implants inclined at 17°. MATERIAL AND METHODS: Three implants were modeled using CAD software following the manufacturer's measurements. Then, implants were duplicated and divided into two groups: one with straight implants and respective abutments, and the other with angled implants at 17° and respective abutments. Both groups were arranged inside a block simulating bone tissue. A simplified fixed prosthesis was installed on both groups and the geometries were exported to CAE software. Five loads of 300N were performed at axial and non-axial points on the fixed prosthesis. Stress on the implants and strain on the block were both analyzed. An in vitro experiment was performed following all structures made in FEA in order to validate the model. In each experimental block, 4 strain gauges were linearly placed between the implants and the same loads were repeated with a loading applicator device. RESULTS: The deformations computed by the gauges were correlated with the FEA results, showing that the group with inclined implants had more damaging biomechanical behavior and was significantly different from the group with straight implants (P<0.005). CONCLUSIONS: The mathematical model used is valid and inclined implants can induce unwanted bone remodeling. Key words:Finite Element Analysis, Dental Implants, Fixed Prosthesis.