Análise comparativa de microgaps em componentes angulares e retos: um estudo de laboratório

rounesp Rev Odontol UNESP Revista de Odontologia da UNESP Rev. Odontol. UNESP 0101-1774 1807-2577 Universidade Estadual Paulista Júlio de Mesquita Filho Resumo Introdução O protocolo de reabilitação com implantes dentários é uma opção de tratamento bem estabelecida para pacientes desdentados com alta taxa de sucesso. No entanto, existem fatores que podem levar à dificuldade de continuidade e até mesmo à perda completa da reabilitação. Microgaps são espaços encontrados entre o implante e o pilar protético que são causados pelo limite de precisão na fabricação do implante. Esse espaço pode causar micromovimentos e microinfiltração bacteriana que podem comprometer a vida útil do implante a longo prazo. Objetivo Medir e avaliar microgaps em implantes angulados e retos usando microscopia eletrônica de varredura. Para a realização do estudo, foram utilizados um total de 30 implantes osseointegrados SIN®, sendo 15 retos e 15 angulados. Material e método Para a análise comparativa desses componentes, foi utilizada a microscopia eletrônica de varredura, realizada por pesquisador devidamente calibrado e experiente. Resultado Observou-se que as medidas de microgaps de ambos os componentes estão de acordo com os valores clinicamente aceitáveis apresentados na literatura, porém os valores de microgaps dos componentes angulados foram consideravelmente maiores em comparação aos componentes retos. Conclusão Embora os valores apresentados corroborem os dados apresentados na literatura, estudos adicionais são necessários para uma compreensão mais abrangente e aprofundada da relação entre os microgaps dos componentes do sistema cone morse. INTRODUCTION Dental implant rehabilitation has become a widely accepted and highly successful treatment option for edentulous patients1-5. As a result, various types of implants and therapeutic protocols have been developed. However, several factors can lead to the failure of the rehabilitation protocol. These include surgical trauma, peri-implant diseases, microleakage, variation in implant anatomy in the crest area, patient age, genetics, systemic conditions, and oral hygiene6-8. Due to its ability to protect the implant from unwanted loads during the bone consolidation phase, the two-piece implant protocol (implant and prosthetic abutment) is widely used. However, the implant and abutment cannot be perfectly aligned due to limitations in precision during their production9. As a result, a gap is created between the prosthetic abutment and the implant (implant-abutment interface). This gap can be a source of micromovements and bacterial microleakage, allowing microorganisms to pass freely between the oral cavity and the internal cavity of the implant1,2,4-6,8-13. The presence of bacteria is closely related to inflammatory processes that can lead to mucositis, peri-implantitis, and eventually bone loss1-14. The health of the soft tissues and the size of the implant-abutment interface strictly depend on the material of the prosthetic abutment, as well as its design, surface topography, and preparation8. Currently, most implants are made of titanium and its alloys8-15, and according to Liu, Yang9, the microgap in titanium implants is considerably smaller than in zirconia implants. In different Morse cone implant systems, the degree of conicity and the connection area vary, which are primarily responsible for differences in bacterial penetration. The applied torque value is also important. Generally, a large connection area results in a small degree of conicity, and a high torque value translates to a low level of bacterial microleakage9. The most recommended technique for evaluating and measuring the implant-abutment interface is scanning electron microscopy (SEM)6. This technique provides high-resolution images with great depth of field of the object while maintaining a fixed and predetermined position6. Studies assessing microgaps in SIN implants are scarce in the literature. Therefore, the aim of this work was to evaluate and measure microgaps at the interface using SEM. MATERIAL AND METHOD This laboratory study evaluated the interface between the dental implant and the prosthetic abutment in order to measure the microgaps. It was conducted at the Department of Dentistry at the Federal University of Sergipe (UFS, Brazil), in collaboration with the Department of Physics and Materials Engineering. Sample Characterization A total of 30 osseointegrated SIN® implants (São Paulo, Brazil) were used, made of commercially pure titanium (c. p Ti), conforming to the NBR ISO 5832 standard16, sized 3.8 x 11.5 mm with a Morse Cone prosthetic system. The samples were subdivided into two groups: 15 were coupled with straight abutments of AIMP 4003C-H 4.0 mm, and 15 were coupled with angled abutments of AIAM 4003C-H 4.0 mm and 3.0 mm. Sample Analysis For the comparative analysis of the microgaps in the samples, scanning electron microscopy (SEM) (JSM-6510 LV, JEOL USA, Inc) with an acceleration voltage of 5 kV was used. Measurements were taken by a single, properly calibrated, and experienced researcher. SEM magnifications of 4,000 times were used, with captures obtained at the micrometer (μm) scale. Five areas (A1-A5) around the circumference between the component and the implant were analyzed. For each area, five measurements were taken, resulting in 150 measurements tabulated in Excel 16.0 (Microsoft, Washington, USA). Statistical Analysis The Shapiro-Wilk normality test was applied, and for comparison between groups, the Mann-Whitney test for independent variables was used. The significance level for all tests was set at 5% (p ≤ 0.05). Data were analyzed using Bioestat 5.0 software17. RESULT After the microscopy analyses, the microgaps were measured in micrometers and tabulated as shown in Figure 1. Figure 2 demonstrates a comparison of the size of microgaps from the t-test results, showing that the angled components have larger microgap values than the straight components. The sample group of angled components (CA) and the sample group of straight components (CR) were analyzed separately and comparatively. Figure 1 SEM analysis of the straight prosthetic component in different regions demonstrating the microgap between prosthetic abutment and implant in a magnificence of 4000 times. Figure 2 Comparison of microgap sizes between straight and Angled Components. Table 1 shows the results of the Shapiro-Wilk test and presents the mean microgap values separated by groups (A1 to A5), their standard deviation, and the p-value. It is notable that the mean values at the ends of both components are higher than their average values, but the discrepancy is more pronounced in the straight components. Regarding standard deviation values, a similar pattern to the mean microgaps is observed; however, in angled components, the standard deviation values are more standardized regardless of the region. Table 1 Descriptive Analysis within Samples for Angled and Straight Components. Shapiro-Wilk Test. Straight Component Angled Component Mean SD p value Mean SD p value A1 7.3380 ±2.5102 0.7145 A1 6.2860 ±2.3263 0.0337 A2 2.9513 ±0.9771 0.2669 A2 5.5413 ±3.1729 0.0092 A3 2.1907 ±1.0405 0.1248 A3 4.1247 ±2.9165 0.0945 A4 3.5653 ±2.2232 0.0356 A4 5.3820 ±3.8911 0.0413 A5 7.7953 ±3.6814 0.3110 A5 6.3933 ±3.4407 0.7817 SD = Standard Deviation Table 2 shows the results of the normality Lilliefors test p-value and presents that the p-values ​​are <0.05, then the data follow a normal distribution. Table 3 shows the results of the Mann-Whitney test for independent samples, which present different p-values ​​for each sample. The p-value of the one-tailed test suggests a significant difference between the samples, indicating that one tends to be larger or smaller than the other. The p-value of the two-tailed test is not small enough to indicate a significant difference in general between the sample distributions. Table 2 Inter-sample Analysis for Angled and Straight Components. Non-parametric Sample Analysis. Normality lilliefors test p-value Angled < 0.01 Straight < 0.01 Table 3 Inter-sample Analysis for Angled and Straight Components. Mann-Whitney Test for Independent Samples p-value (one-tailed) 0.0307 p-value (two-tailed) 0.0615 DISCUSSION The long-term success of dental implant rehabilitation demonstrates the effectiveness of this treatment option1-5. However, risks such as material manufacturing defects, surgical errors, and anatomical variations can impede the success of the rehabilitation6-8. Therefore, the connection between the implant and the prosthetic abutment should be as closely aligned as possible to avoid large gaps, thereby preventing micromovements and bacterial microleakage1-2,4-6,8-13. In this context, the images produced in our study using SEM reveal the presence of minimal microgaps in SIN implants, both in straight and angled components. In the Morse Cone connection, fixation and stability depend not only on the fixation screw but also on the friction between the conical parts and the surface of the component18. Emphasizing the importance of the absence of microgaps at the implant/component interface, our study presents the quantification of existing microgaps and their variations within the same manufacturer. This study demonstrates higher average microgap values in the uppermost region (A1) and the lowermost region (A5) for both straight and angled components, with a greater discrepancy between the values at the extremities (A1 and A5) and the central regions (A2, A3, and A4) in straight components. These values contradict the findings of Duraisamy et al.19, who observed smaller values in the upper region and larger values in the lower region, which could be explained by differences in implant designs and brands. Lopes et al.20, in their study of Neodent® implants, reported average values similar to the straight components in our research. However, the maximum values in our study are relatively higher, regardless of the component type. On the other hand, the average values reported by Costa et al.6 differ from those presented in our study, with differences in implant design and brands likely being a determining factor for this discrepancy. After analyzing the statistical data, it can be observed that the microgaps present in this study are within clinically acceptable standards for the joining of components. Aspects such as the precision and stability of the connection between components and implants have been the focus of research by manufacturers aiming to improve the quality of mechanical parts through enhanced machining processes, resulting in greater precision. Additionally, investments in materials that support or minimize screw loosening have been reported in the literature18. Mohammadi et al.11 state that when the abutment is connected to the implant, gaps between the components are inevitable and can become potential sites for bacterial microleakage, which may lead to the infiltration of inflammatory cells. This inflammatory process around the implant can cause peri-implantitis and even bone loss, ultimately affecting the long-term success of the rehabilitation21,22. However, studies by Kowalski et al.8, Duraisamy et al.19, Jemt, Book23, and Solá-Ruíz et al.24 demonstrate that microgaps of less than 10 micrometers do not have harmful effects on either soft or hard tissues. Comparing with our study, it can be concluded that the average microgap values are satisfactory since they are below 10 micrometers. Additionally, due to the stability of the Morse cone system, oxidation between the components is observed in the gap region, similar to cold welding, which sometimes acts as an effective physical seal, preventing bacterial proliferation6. When comparing the average values between these components, a notable disparity is observed in the central regions (A2, A3, and A4), where the values for angled components are significantly higher. This discrepancy can be attributed to the unique design characteristics of these components. Conversely, the average values at the extremities (A1 and A5) between the straight and angled components are similar. Additionally, we identified that some of the analyzed regions did not exhibit parametric distribution, suggesting the possibility of irregularities that could affect the implant adaptation. In the two-piece implant system, although micromovement in conical connections decreases due to precise manufacturing of the implant and abutment, the current production process cannot eliminate micromovement entirely. A limitation of this study include that the microgap was evaluated in the absence of loading mechanics. Future studies should assess the microgap under the combined application of dynamic mechanical testing and fatigue, where micromovements produced by chewing could lead to significant micro-adaptations between the abutment and implant that are important for clinical practice. CONCLUSION In light of the above, we can conclude that microgaps are present in both straight and angled components, and they are within clinically acceptable limits. The results show higher microgap values in the angled component group, suggesting conformational changes related to manufacturing. Additional studies are needed for a more comprehensive and in-depth understanding of the relationship between microgaps in Morse cone system components. ACKNOWLEDGEMENTS This research utilized facilities at the Multi-User Nanotechnology Center of UFS (CMNano-UFS), a National Multi-User Research Center supported by the Funding Authority for Studies and Projects (FINEP). We thank the technical support provided by the CMNano-UFS teams during the experiments of proposal 085/2023. The provision of implant samples was granted by SINGULAR Implants®. This work was supported by the Coordination for the Improvement of Higher Education Personnel-Brazil (CAPES) - Funding Code 001. How to cite: Lobo YL, Mendes GN, Santana LAM, Floresta LG, Marqueti AC, Takeshita WM, et al. Comparative analysis of microgaps in angled and straight components: a laboratory study. Rev Odontol UNESP. 2024;53:e20240024. https://doi.org/10.1590/1807-2577.02424 REFERENCES 1 Cascos R Celemín-Viñuela A Mory-Rubiños N Gómez-Polo C Ortega R Agustín-Panadero R Influence of the use of transepithelial abutments vs. titanium base abutments on microgap formation at the dental implant–abutment interface: an in vitro study Materials (Basel) 2023 16 19 6532 http://doi.org/10.3390/ma16196532 37834669 1 Cascos R, Celemín-Viñuela A, Mory-Rubiños N, Gómez-Polo C, Ortega R, Agustín-Panadero R, et al. Influence of the use of transepithelial abutments vs. titanium base abutments on microgap formation at the dental implant–abutment interface: an in vitro study. Materials (Basel). 2023;16(19):6532. http://doi.org/10.3390/ma16196532. PMid:37834669. 2 Carlos LV Carlos NC Sm Karina L Sunil BK Carlos PE Olga LG Comparative study of bacterial microfiltration in the implant-abutment interface, with straight and conical internal connections, in vitro Clin Exp Dent Res 2021 12 7 6 1014 1024 http://doi.org/10.1002/cre2.439 34151544 2 Carlos LV, Carlos NC, Sm Karina L, Sunil BK, Carlos PE, Olga LG. Comparative study of bacterial microfiltration in the implant-abutment interface, with straight and conical internal connections, in vitro. Clin Exp Dent Res. 2021 Dec;7(6):1014-24. http://doi.org/10.1002/cre2.439. PMid:34151544. 3 Baseri M Radmand F Hamedi R Yousefi M Kafil HS Immunological aspects of dental implant rejection BioMed Res Int 2020 12 2020 7279509 http://doi.org/10.1155/2020/7279509 33376734 3 Baseri M, Radmand F, Hamedi R, Yousefi M, Kafil HS. Immunological aspects of dental implant rejection. BioMed Res Int. 2020 Dec;2020:7279509. http://doi.org/10.1155/2020/7279509. PMid:33376734. 4 Khajavi A Mohseni S Peymani A Amjadi M In vitro bacterial leakage at the implant-abutment connection of two dental implant systems with internal connection Front Dent 2020 12 17 32 http://doi.org/10.18502/fid.v17i32.5196 36042810 4 Khajavi A, Mohseni S, Peymani A, Amjadi M. In vitro bacterial leakage at the implant-abutment connection of two dental implant systems with internal connection. Front Dent. 2020 Dec;17:32. http://doi.org/10.18502/fid.v17i32.5196. PMid:36042810. 5 Vélez J Peláez J López-Suárez C Agustín-Panadero R Tobar C Suárez MJ Influence of implant connection, abutment design and screw insertion torque on implant-abutment Misfit J Clin Med 2020 7 24 9 8 2365 https://doi.org/10.3390/jcm9082365 5 Vélez J, Peláez J, López-Suárez C, Agustín-Panadero R, Tobar C, Suárez MJ. Influence of implant connection, abutment design and screw insertion torque on implant-abutment Misfit. J Clin Med. 2020 Jul 24;9(8):2365. https://doi.org/10.3390/jcm9082365. PMid: 32722131. 6 Costa MB Ferreira LF Takeshita WM Marqueti AC Trento CL Evaluation of the interface between the straight prosthetic component and the Morse Cone-type internal connection of the dental implant in cross section by scanning electron microscopy Rev Odontol UNESP 2020 49 e20200033 http://doi.org/10.1590/1807-2577.03320 6 Costa MB, Ferreira LF, Takeshita WM, Marqueti AC, Trento CL. Evaluation of the interface between the straight prosthetic component and the Morse Cone-type internal connection of the dental implant in cross section by scanning electron microscopy. Rev Odontol UNESP. 2020;49:e20200033. http://doi.org/10.1590/1807-2577.03320. 7 Ertem SY Gungormus M Ozdogan MS Orhan M A microbiological assessment of peri-implant sites and implant-abutment interfaces in diabetic and healthy individuals Int J Clin Exp Med 2020 13 1 208 215 7 Ertem SY, Gungormus M, Ozdogan MS, Orhan M. A microbiological assessment of peri-implant sites and implant-abutment interfaces in diabetic and healthy individuals. Int J Clin Exp Med. 2020;13(1):208-15. 8 Kowalski J Puszkarz AK Radwanski M Sokolowski J Cichomski M Bourgi R Micro-CT evaluation of microgaps at implant-abutment connection Materials (Basel) 2023 6 16 12 4491 http://doi.org/10.3390/ma16124491 37374674 8 Kowalski J, Puszkarz AK, Radwanski M, Sokolowski J, Cichomski M, Bourgi R, et al. Micro-CT evaluation of microgaps at implant-abutment connection. Materials (Basel). 2023 Jun;16(12):4491. http://doi.org/10.3390/ma16124491. PMid:37374674. 9 Liu Y Wang J Influences of microgap and micromotion of implant-abutment interface on marginal bone loss around implant neck Arch Oral Biol 2017 11 83 153 160 http://doi.org/10.1016/j.archoralbio.2017.07.022 28780384 9 Liu Y, Wang J. Influences of microgap and micromotion of implant-abutment interface on marginal bone loss around implant neck. Arch Oral Biol. 2017 Nov;83:153-60. http://doi.org/10.1016/j.archoralbio.2017.07.022. PMid:28780384. 10 Mao Z Beuer F Wu D Zhu Q Yassine J Schwitalla A Microleakage along the implant-abutment interface: a systematic review and meta-analysis of in vitro studies Int J Implant Dent 2023 9 9 1 34 http://doi.org/10.1186/s40729-023-00494-y 37733145 10 Mao Z, Beuer F, Wu D, Zhu Q, Yassine J, Schwitalla A, et al. Microleakage along the implant-abutment interface: a systematic review and meta-analysis of in vitro studies. Int J Implant Dent. 2023 Sep;9(1):34. http://doi.org/10.1186/s40729-023-00494-y. PMid:37733145. 11 Mohammadi F Hajmousaei M Vaziri N Arshad M Bacterial leakage at implant-abutment interface with different intermediate materials J Oral Implantol 2019 12 45 6 451 455 http://doi.org/10.1563/aaid-joi-D-18-00313 31580765 11 Mohammadi F, Hajmousaei M, Vaziri N, Arshad M. Bacterial leakage at implant-abutment interface with different intermediate materials. J Oral Implantol. 2019 Dec;45(6):451-5. http://doi.org/10.1563/aaid-joi-D-18-00313. PMid:31580765. 12 Molinero-Mourelle P Cascos-Sanchez R Yilmaz B Lam WYH Pow EHN Del Río Highsmith J Effect of fabrication technique on the microgap of CAD/CAM cobalt-chrome and zirconia abutments on a conical connection implant: an in vitro study Materials (Basel) 2021 4 14 9 2348 http://doi.org/10.3390/ma14092348 33946477 12 Molinero-Mourelle P, Cascos-Sanchez R, Yilmaz B, Lam WYH, Pow EHN, Del Río Highsmith J, et al. Effect of fabrication technique on the microgap of CAD/CAM cobalt-chrome and zirconia abutments on a conical connection implant: an in vitro study. Materials (Basel). 2021 Apr;14(9):2348. http://doi.org/10.3390/ma14092348. PMid:33946477. 13 Vinhas AS Aroso C Salazar F López-Jarana P Ríos-Santos JV Herrero-Climent M Review of the mechanical behavior of different implant-abutment connections Int J Environ Res Public Health 2020 11 17 22 8685 http://doi.org/10.3390/ijerph17228685 33238476 13 Vinhas AS, Aroso C, Salazar F, López-Jarana P, Ríos-Santos JV, Herrero-Climent M. Review of the mechanical behavior of different implant-abutment connections. Int J Environ Res Public Health. 2020 Nov;17(22):8685. http://doi.org/10.3390/ijerph17228685. PMid:33238476. 14 Gehrke P Burg S Peters U Beikler T Fischer C Rupp F Bacterial translocation and microgap formation at a novel conical indexed implant abutment system for single crowns Clin Oral Investig 2022 2 26 2 1375 1389 http://doi.org/10.1007/s00784-021-04112-2 34401947 14 Gehrke P, Burg S, Peters U, Beikler T, Fischer C, Rupp F, et al. Bacterial translocation and microgap formation at a novel conical indexed implant abutment system for single crowns. Clin Oral Investig. 2022 Feb;26(2):1375-89. http://doi.org/10.1007/s00784-021-04112-2. PMid:34401947. 15 Lauritano D Moreo G Lucchese A Viganoni C Limongelli L Carinci F The impact of implant-abutment connection on clinical outcomes and microbial colonization: a narrative review Materials (Basel) 2020 3 13 5 1131 http://doi.org/10.3390/ma13051131 32138368 15 Lauritano D, Moreo G, Lucchese A, Viganoni C, Limongelli L, Carinci F. The impact of implant-abutment connection on clinical outcomes and microbial colonization: a narrative review. Materials (Basel). 2020 Mar;13(5):1131. http://doi.org/10.3390/ma13051131. PMid:32138368. 16 Associação Brasileira de Normas Técnicas – ABNT NBR ISO 5832: Implantes para cirurgia - Materiais metálicos Rio de Janeiro ABNT 2008 16 Associação Brasileira de Normas Técnicas – ABNT. NBR ISO 5832: Implantes para cirurgia - Materiais metálicos. Rio de Janeiro: ABNT; 2008. 17 Ayres M Ayres M Jr Ayres DL BioEstat: aplicações estatísticas nas áreas das ciências biomédicas. 5. Belém Sociedade Civil Mamirauá 2007 17 Ayres M, Ayres M Jr, Ayres DL. BioEstat: aplicações estatísticas nas áreas das ciências biomédicas. 5. ed. Belém: Sociedade Civil Mamirauá; 2007. 18 da Silva-Neto JP Nóbilo MA Penatti MP Simamoto PC Jr das Neves FD Influence of methodologic aspects on the results of implant-abutment interface microleakage tests: a critical review of in vitro studies Int J Oral Maxillofac Implants 2012 Jul-Aug 27 4 793 800 22848880 18 da Silva-Neto JP, Nóbilo MA, Penatti MP, Simamoto PC Jr, das Neves FD. Influence of methodologic aspects on the results of implant-abutment interface microleakage tests: a critical review of in vitro studies. Int J Oral Maxillofac Implants. 2012 Jul-Aug;27(4):793-800. PMid:22848880. 19 Duraisamy R Krishnan CS Ramasubramanian H Sampathkumar J Mariappan S Navarasampatti Sivaprakasam A Compatibility of nonoriginal abutments with implants: evaluation of microgap at the implant-abutment interface, with original and nonoriginal abutments Implant Dent 2019 6 28 3 289 295 http://doi.org/10.1097/ID.0000000000000885 31124826 19 Duraisamy R, Krishnan CS, Ramasubramanian H, Sampathkumar J, Mariappan S, Navarasampatti Sivaprakasam A. Compatibility of nonoriginal abutments with implants: evaluation of microgap at the implant-abutment interface, with original and nonoriginal abutments. Implant Dent. 2019 Jun;28(3):289-95. http://doi.org/10.1097/ID.0000000000000885. PMid:31124826. 20 Lopes PA Carreiro AFP Nascimento RM Vahey BR Henriques B Souza JCM Physicochemical and microscopic characterization of implant-abutment joints Eur J Dent 2018 Jan-Mar 12 1 100 104 http://doi.org/10.4103/ejd.ejd_3_17 29657532 20 Lopes PA, Carreiro AFP, Nascimento RM, Vahey BR, Henriques B, Souza JCM. Physicochemical and microscopic characterization of implant-abutment joints. Eur J Dent. 2018 Jan-Mar;12(1):100-4. http://doi.org/10.4103/ejd.ejd_3_17. PMid:29657532. 21 Hermann JS Schoolfield JD Schenk RK Buser D Cochran DL Influence of the size of the microgap on crestal bone changes around titanium implants. A histometric evaluation of unloaded non-submerged implants in the canine mandible J Periodontol 2001 10 72 10 1372 1383 http://doi.org/10.1902/jop.2001.72.10.1372 11699479 21 Hermann JS, Schoolfield JD, Schenk RK, Buser D, Cochran DL. Influence of the size of the microgap on crestal bone changes around titanium implants. A histometric evaluation of unloaded non-submerged implants in the canine mandible. J Periodontol. 2001 Oct;72(10):1372-83. http://doi.org/10.1902/jop.2001.72.10.1372. PMid:11699479. 22 Adell R Lekholm U Rockler B Brånemark PI Lindhe J Eriksson B Marginal tissue reactions at osseointegrated titanium fixtures (I). A 3-year longitudinal prospective study Int J Oral Maxillofac Surg 1986 2 15 1 39 52 http://doi.org/10.1016/S0300-9785(86)80010-2 3083005 22 Adell R, Lekholm U, Rockler B, Brånemark PI, Lindhe J, Eriksson B, et al. Marginal tissue reactions at osseointegrated titanium fixtures (I). A 3-year longitudinal prospective study. Int J Oral Maxillofac Surg. 1986 Feb;15(1):39-52. http://doi.org/10.1016/S0300-9785(86)80010-2. PMid:3083005. 23 Jemt T Book K Prosthesis misfit and marginal bone loss in edentulous implant patients Int J Oral Maxillofac Implants 1996 Sep-Oct 11 5 620 625 8908860 23 Jemt T, Book K. Prosthesis misfit and marginal bone loss in edentulous implant patients. Int J Oral Maxillofac Implants. 1996 Sep-Oct;11(5):620-5. PMid:8908860. 24 Solá-Ruíz MF Selva-Otaolaurruchi E Senent-Vicente G González-de-Cossio I Amigó-Borrás V Accuracy combining different brands of implants and abutments Med Oral Patol Oral Cir Bucal 2013 3 18 2 e332 6 http://doi.org/10.4317/medoral.18137 23229250 24 Solá-Ruíz MF, Selva-Otaolaurruchi E, Senent-Vicente G, González-de-Cossio I, Amigó-Borrás V. Accuracy combining different brands of implants and abutments. Med Oral Patol Oral Cir Bucal. 2013 Mar;18(2):e332-6. http://doi.org/10.4317/medoral.18137. PMid:23229250.