Análisis del comportamiento mecánico in vitro de prótesis parciales fijas sobre implantes dentales con cuello convergente y conexión interna transmucosa con voladizo posterior

Objetivos: El propósito de la investigación fue analizar a través de un estudio in vitro el comportamiento mecánico de 4 uniones distintas en la interfase pilar implante sobre prótesis parciales fijas con dos implantes dentales (cuello convergente y conexión interna transmucosa) y un voladizo posterior tras unos test de fatiga mecánica y posterior carga compresiva. Material y método: Se realizó un estudio in vitro con 4 grupos, grupo 1 atornillado directo (AD), grupo 2, atornillado In (AIN), grupo 3 cementado In (CIN) y grupo 4 cementado directo (CD) utilizando 19 muestras por grupo con dos implantes cada uno y sus respectivas prótesis. Tras el diseño en Cad-Cam de las muestras y su posterior montaje estandarizado, se procedió a la realización de los ensayos según los requisitos y métodos especificados en la norma UNE-EN ISO 14801:2008, correspondientes a ensayos de fatiga dinámica para implantes dentales endoóseos. Las pruebas se realizaron con la máquina simuladora de masticación (Chewing Simulator CS-4.2) aplicando una carga de 80N durante 240.000 ciclos y tras su posterior análisis, se realizaron las pruebas de carga compresiva con el Shimadzu® AG con un célula de carga de 100 KN y una velocidad de desplazamiento de 0,5 mm/min aplicando la carga hasta el fallo de alguno de los componentes en la interfaz prótesis-implante pilar. Posteriormente se realizó un análisis por superposición digital y microscopia óptica para obtener más datos sobre que había ocurrido en cada grupo. Resultados: Tras el análisis al microscopio óptico, la superposición digital de las muestras y los resultados de los ensayos, podemos afirmar que el grupo 1 (prótesis atornillada directa cad-cam) AD obtiene los mayores valores de resistencia media con 663,5 N respecto a los otros tres, muy homogéneos entre sí 428,4 N grupo 2 (AIN); 486,7 N grupo 3 (CIN) y 458,9 N grupo 4 (CD). La resistencia media depende significativamente del tipo de conexión (p <0,001) y esta diferencia es similar para cualquiera de las condiciones de ensayo (p = 0,689). Los grupos 3 y 4 muestran las mayores deformaciones en la interfase prótesis-implante pilar. Conclusiones: Podemos concluir que las prótesis sobre implantes dentales con cuello convergente y conexión interna transmucosa con voladizo posterior atornillada directamente a la conexión del implante es una buena solución en los casos en los que no es posible colocar implantes para evitar extensiones.Objectives: The purpose of the research was to analyze through an in vitro study the mechanical behavior of 4 different connections at the dental prosthesis-implant abutment interface on fixed partial prostheses with two dental implants (convergent neck and transmucosal internal connection) and a posterior cantilever extension after an in vitro mechanical fatigue test and cyclic loading. Material and methods: An in vitro study was carried out with 4 groups using 20 samples per group with two implants each and their respective prostheses. After the Cad-Cam design of the samples and their subsequent standardized assembly, the tests were carried out according to the requirements and methods specified in the UNE-EN ISO 1480: 2007 standard, corresponding to dynamic fatigue tests for endosseous dental implants. The tests were carried out with the chewing simulator machine (Chewing Simulator CS-4.2) applying a load of 80N during 1 million cycles and after its subsequent analysis, the cyclic load tests were carried out with the Shimadzu® AG ‐ 100 KN with a 100 KN load cell and a displacement speed of 0.5 mm / min applying the load until the failure of a component in the prosthesis-implant abutment interface. Results: After the optical microscopic analysis of the samples and the results of the tests, we can affirm that group 1 (direct cad-cam screw-retained prosthesis) obtains the highest values of mean resistance with 712N versus 404N group 2, 495N group 3 and 447N group 4 The mean resistance significantly depends on the type of connection (p <0.001) and this difference is similar for any of the test conditions (p = 0.689). Groups 3 and 4 show the highest deformations in the prosthesis-implant abutment interface. Conclusions: We can conclude that prostheses on dental implants with convergent neck and transmucosal internal connection with posterior cantilever screwed directly to the implant connection is a good solution in cases where it is not possible to place implants to avoid extensions

Narrow-diameter implants: are they a predictable treatment option? A literature review

Objective: To evaluate the predictability of narrow-diameter implants as a treatment option in routine clinical practice. A literature review was performed of studies reporting clinical results obtained with these implants. Survival rates, peri-implant bone loss and related complications were evaluated. The working hypothesis was that narrow-diameter implants offer clinical results similar to those obtained with implants of greater diameter. Material and Methods: A Medline-PubMed search covering the period between 2002 and 2012 was carried out. Studies published in English and with a follow-up period of at least 12 months were considered for inclusion. A manual search was also conducted in different journals with an important impact factor. Results: Twenty-one studies meeting the screening criteria were included in the literature review. A total of 2980 narrow-diameter implants placed in 1607 patients were analyzed. Conclusions: The results obtained from the literature indicate that narrow-diameter implants are a predictable treatment option, since they afford clinical results comparable to those obtained with implants of greater diameter

Predictability of short implants ( < 10 mm) as a treatment option for the rehabilitation of atrophic maxillae: a systematic review

Background: Short implants (< 10 mm) are one of the treatment options available in cases of limited vertical bone. Although such implants are now widely used, there is controversy regarding their clinical reliability. The purpose of this paper is to evaluate the predictability of short implants as an alternative to technically more complex treatments in patients with atrophic maxillae, based on a systematic review of the literature and the analysis of the implant survival rates, changes in peri-implant bone level, and associated complications. It is postulated that short implants offer clinical results similar to those of longer implants. Material and Methods: A Medline-PubMed search was made covering the period between January 2004 and December 2014 (both included). Studies in English published in indexed journals, involving at least 20 implants and with a follow-up period of at least 12 months were considered. A manual search in four high impact journals was also conducted. Results: A total of 37 studies meeting the inclusion criteria were included in this review. 9792 implants placed in over 5000 patients were analyzed. Conclusions: Based on the results of this review, short implants are seen to offer clinical results in terms of survival, bone loss and complications similar to those of longer implants

Comparative Analysis of Peri-Implant Bone Loss in Extra-Short, Short, and Conventional Implants. A 3-Year Retrospective Study

Objective: To evaluate the influence of implant length on marginal bone loss, comparing implants of 4 mm, 6 mm, and >8 mm, supporting two splinted crowns after 36-month functional loading. Materials and Methods: this retrospective clinical trial evaluated the peri-implant behavior of splinted crowns (two per case) on pairs of implants of the same length placed in the posterior maxilla (molar area). Implants were divided into three groups according to length (Group 1: extra-short 4 mm; Group 2: short 6 mm; Group 3: conventional length >8 mm). Marginal bone loss was analyzed using standardized periapical radiographs at the time of loading and 36 months later. Results: 24 patients (19 women and 5 men) were divided into three groups, eight rehabilitations per group, in the position of the maxillary first and second molars. The 48 Straumann® Standard Plus (Regular Neck (RN)/Wide Neck (WN)) implants were examined after 36 months of functional loading. Statistical analysis found no significant differences in bone loss between the three groups (p = 0.421). No implant suffered biological complications or implant loss. Long implants were associated with less radiographic bone loss. Conclusions: extra-short (4 mm); short (6 mm); and conventional length (>8 mm) implants in the posterior maxilla present similar peri-implant bone loss and 100% survival rates in rehabilitation, by means of two splinted crowns after 36 months of functional loading. Implants placed in posterior positions present better bone loss results than implants placed in anterior positions, regardless of the interproximal area where bone loss is measured. Conventional lengthOdontologí

Implant-Supported Fixed Partial Dentures with Posterior Cantilevers: In Vitro Study of Mechanical Behavior

Rehabilitation with dental implants is not always possible due to the lack of bone quality or quantity, in many cases due to bone atrophy or the morbidity of regenerative treatments. We find ourselves in situations of performing dental prostheses with cantilevers in order to rehabilitate our patients, thus simplifying the treatment. The aim of this study was to analyze the mechanical behavior of four types of fixed partial dentures with posterior cantilevers on two dental implants (convergent collar and transmucosal internal connection) through an in vitro study (compressive loading and cyclic loading). This study comprised four groups (n = 76): in Group 1, the prosthesis was screwed directly to the implant platform (DS; n = 19); in Group 2, the prosthesis was screwed to the telescopic interface on the implant head (INS; n = 19); in Group 3, the prosthesis was cemented to the telescopic abutment (INC; n = 19); and in Group 4, the prosthesis was cemented to the abutment (DC; n = 19). The sets were subjected to a cyclic loading test (80 N load for 240,000 cycles) and compressive loading test (100 KN load at a displacement rate of 0.5 mm/min), applying the load until failure occurred to any of the components at the abutment–prosthesis–implant interface. Subsequently, an optical microscopy analysis was performed to obtain more data on what had occurred in each group. Results: Group 1 (direct screw-retained prosthesis, DS) obtained the highest mean strength value of 663.5 ± 196.0 N. The other three groups were very homogeneous: 428.4 ± 63.1 N for Group 2 (INS), 486.7 ± 67.8 N for Group 3 (INC), and 458.9 ± 38.9 N for Group 4 (DC). The mean strength was significantly dependent on the type of connection (p < 0.001), and this difference was similar for all of the test conditions (cyclic and compressive loading) (p = 0.689). Implant-borne prostheses with convergent collars and transmucosal internal connections with posterior cantilevers screwed directly to the implant connection are a good solution in cases where implant placement cannot avoid extensions.Odontologí

Microtensile Bond Strength of CAD-CAM Restorative Dental Material Blocks to Resin Cement: An In Vitro Study

Introduction: Today’s dentistry frequently employs bonded partial restorations, which are usually fabricated in ceramic materials. In the last decade, hybrid materials have emerged that attempt to combine the properties of composites and ceramics. Objectives: To evaluate in vitro, by means of a microtensile test, the bond strength between CAD-CAM restorative materials and the cement recommended by their manufacturer. Material and Method: From blocks of CAD-CAM restorative material bonded to composite blocks (Filtek 500®), beams with a bonding area of approximately 1 mm2 were made and divided into four groups: EMAX (IPS e.max CAD® lithium disilicate), VE (VITA Enamic® polymer-infiltrated ceramic matrix), LUA (Lava Ultimate® nano-ceramic resin with sandblasting protocol) and LUS (Lava Ultimate® nano-ceramic resin with silica coating protocol). In each group, perimeter (external) or central (internal) beams were differentiated according to the position in the block. The samples were tested on the LMT 100® microtensile machine. Using optical microscopy, the fractures were categorized as adhesive or cohesive (of the restorative material or composite), and the data were analysed with parametric tests (ANOVA). Results: The LUS group had the highest results (42 ± 20 MPa), followed by the LUA group (38 ± 18 MPa). EMAX had a mean of 34 ± 16 MPa, and VE was the lowest in this study (30 ± 17 MPa). In all groups, the central beams performed better than the perimeter beams. Both EMAX and VE had the most adhesive fractures, while LUA and LUS had a predominance of cohesive fractures. Conclusions: Lava Ultimate® nanoceramic resin with the silica coating protocol obtains the best bond strength valuesOdontologí

Predictability of short implants ( < 10 mm) as a treatment option for the rehabilitation of atrophic maxillae. A systematic review

Background: Short implants (< 10 mm) are one of the treatment options available in cases of limited vertical bone. Although such implants are now widely used, there is controversy regarding their clinical reliability. The purpose of this paper is to evaluate the predictability of short implants as an alternative to technically more complex treatments in patients with atrophic maxillae, based on a systematic review of the literature and the analysis of the implant survival rates, changes in peri-implant bone level, and associated complications. It is postulated that short implants offer clinical results similar to those of longer implants. Material and Methods: A Medline-PubMed search was made covering the period between January 2004 and December 2014 (both included). Studies in English published in indexed journals, involving at least 20 implants and with a follow-up period of at least 12 months were considered. A manual search in four high impact journals was also conducted. Results: A total of 37 studies meeting the inclusion criteria were included in this review. 9792 implants placed in over 5000 patients were analyzed. Conclusions: Based on the results of this review, short implants are seen to offer clinical results in terms of survival, bone loss and complications similar to those of longer implants.Sin financiación1.284 JCR (2018) Q3, 65/91 Dentistry, Oral Surgery & MedicineUE

Narrow-diameter implants: Are they a predictable treatment option? A literature review

Objective: To evaluate the predictability of narrow-diameter implants as a treatment option in routine clinical practice. A literature review was performed of studies reporting clinical results obtained with these implants. Survival rates, peri-implant bone loss and related complications were evaluated. The working hypothesis was that narrow-diameter implants offer clinical results similar to those obtained with implants of greater diameter. Material and Methods: A Medline-PubMed search covering the period between 2002 and 2012 was carried out. Studies published in English and with a follow-up period of at least 12 months were considered for inclusion. A manual search was also conducted in different journals with an important impact factor. Results: Twenty-one studies meeting the screening criteria were included in the literature review. A total of 2980 narrow-diameter implants placed in 1607 patients were analyzed. Conclusions: The results obtained from the literature indicate that narrow-diameter implants are a predictable treatment option, since they afford clinical results comparable to those obtained with implants of greater diameter.Sin financiación1.171 JCR (2014) Q3, 50/88 Dentistry, Oral Surgery & MedicineUE

Influence of print orientation on the accuracy (trueness and precision) of diagnostic casts manufactured with a daylight polymer printer.

STATEMENT OF PROBLEM Print orientation may affect the manufacturing accuracy of vat-polymerized diagnostic casts. However, its influence should be analyzed based on the manufacturing trinomial (technology, printer, and material) and printing protocol used to manufacture the casts. PURPOSE The purpose of this in vitro study was to measure the influence of different print orientations on the manufacturing accuracy of vat-polymerized polymer diagnostic casts. MATERIAL AND METHODS A standard tessellation language (STL) reference file containing a maxillary virtual cast was used to manufacture all specimens using a vat-polymerization daylight polymer printer (Photon mono SE. LCD 2K) and a model resin (Phrozen Aqua Gray 4K). All specimens were manufactured using the same printing parameters, except for print orientation. Five groups were created depending on the print orientation: 0, 22.5, 45, 67.5, and 90 degrees (n=10). Each specimen was digitized using a desktop scanner. The discrepancy between the reference file and each of the digitized printed casts was measured using the Euclidean measurements and root mean square (RMS) error (Geomagic Wrap v.2017). Independent (unpaired) sample t tests and multiple pairwise comparisons using the Bonferroni test were used to analyze the trueness of the Euclidean distances and RMS data. Precision was assessed using the Levene test (α=.05). RESULTS In terms of Euclidean measurements, significant differences in trueness and precision values were found among the groups tested (P<.001). The 22.5- and 45-degree groups resulted in the best trueness values, and the 67.5-degree group had the lowest trueness value. The 0- and 90-degree groups led to the best precision values, while the 22.5-, 45-, and 67.5-degree groups showed the lowest precision values. Analyzing the RMS error calculations, significant differences in trueness and precision values were found among the groups tested (P<.001). The 22.5-degree group had the best trueness value, and the 90-degree group resulted in the lowest trueness value among the groups. The 67.5-degree group led to the best precision value, and the 90-degree group to the lowest precision value among the groups. CONCLUSIONS Print orientation influenced the accuracy of diagnostic casts fabricated by using the selected printer and material. However, all specimens had clinically acceptable manufacturing accuracy ranging between 92 μm and 131 μm

An additively manufactured, magnetically retained, and stackable implant surgical guide: A dental technique

The digital workflow for designing and fabricating a magnetically retained and stackable additively manufactured implant surgical guide is described. The technique should improve the stability of the stackable surgical guide and the accuracy of implant placement.Odontologí