Estudio comparativo in vitro de distintos métodos de extracción de tornillos fracturados en implantes

En los tratamientos sobre implantes, pueden aparecer complicaciones como la fractura de los tornillos que sujetan las prótesis que van sobre ellos. El objetivo principal de esta investigación fue evaluar in vitro la efectividad de los sistemas mecánicos de extracción de tornillos fracturados en implanto-prótesis. Material y Método: Se utilizaron 180 muestras que consistían en un implante de conexión interna Sweden&Martina® con un pilar prefabricado de titanio Sweden&Martina®, que se atornillaba al implante con un tornillo de titanio, de la misma casa comercial. Cada una de las muestras fue sometida a una carga cíclica y posteriormente a una carga de compresión hasta conseguir la fractura de los tornillos. Cada muestra fue clasificada según el tipo de fractura que presentaba y fueron numeradas del 1 al 180 de forma aleatoria, distribuyéndolas entre los tres operadores de forma aleatoria. Cada operador recibió 60 muestras, de las cuales extraería 15 con el método convencional, 15 con el método Rhein®, 15 con el método Sanhigia® y 15 con el método Phibo®. Se realizó una tabla reuniendo todos los datos obtenidos de los distintos operadores y se sometieron a un estudio estadístico. Resultados: El 51,7% de los tornillos presentaban fractura a nivel coronal, el 35% a nivel medio y el 13,3% a nivel apical se vio que el 40% de los especímenes presentaban movilidad inicial, encontrando 72 tornillos móviles y 108 tornillos fijos. Cuando el tornillo se movía, la probabilidad de éxito fue doce veces mayor respecto a la inmovilidad previa del tornillo (OR=12,4; p<0,001). Cuando valoramos las tasas de éxito según los operadores, estas fueron similares para todos (p=0,371). Si valorábamos si el tornillo se había fracturado a nivel coronal, medio o apical y en qué caso era más fácil o difícil la extracción de este tornillo, se vio que la localización de la fractura no afectaba al éxito de la extracción (p=0,530). La rosca interna del implante se presentó afectada tras el proceso en el 9,8% de los casos de éxito. El tiempo medio de extracción fue de 3,17 ± 2,52 min y la mediana se cifró en 2,22 min (IQR: 0,81-2,88), esto sugirió una distribución algo asimétrica. El método Rhein83® fue el mejor valorado por todos los operadores. Conclusiones: -La utilización de los sistemas de extracción de tornillos implanto-protésicos han conseguido la retirada de 123 tornillos rotos (68,3%). - El método Rhein83® alcanza una tasa de éxito del 84,4%, el método Phibo® y el convencional del 71,1% y el método Sanhigia® solo del 46,7%. - El tiempo de extracción de los tornillos se ve influenciado por diferentes variables. - La movilidad inicial del fragmento ha influido en los resultados alcanzados. - La posición ápico-coronal del fragmento roto, no ha influido en la dificultad para la retirada del mismo. - La rosca interna de los implantes no se ha visto afectada estadísticamente. -La experiencia clínica del operador no parece influir en la tasa de éxito. -El sistema Rhein83® es el elegido por los operadores. - Se necesitan más estudios in vitro e in vivo

Oral rehabilitation with the new SG® attachment in a patient treated for oral squamous cell carcinoma

In patients who have undergone surgery and radiotherapy for oral squamous cell carcinoma (OSCC), the posterior oral rehabilitation may prove complex. In addition to the defects produced by surgical ablation of the primary tumor, radiotherapy induces deleterious effects upon the oral tissues. We present the case of a 48-year-old male treated two years before due to OSCC in the retromolar trigone and left lateral wall of the oropharynx. Following study of the case with clinical examination and orthopantomography, a management plan was defined involving rehabilitation of the upper dental arch with fixed ceramometallic prostheses, while in the lower arch we chose a unilateral removable prosthesis adapted to a fixed prosthesis by means of a special and versatile attachment based on a new system that functions as a fixed element but which can be removed or changed at some later date. The present clinical case illustrates this type of prosthodontic solution for the management of oncological patients of this kind

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

Accuracy combining different brands of implants and abutments

Objective: To evaluate the vertical misfit between different brands of dental implants and prosthetic abutments, with or without mechanical torque, and to study their possible combination. Study design: Five different brands of implant were used in the study: Biofit (Castemaggiore, Italy), Bioner S.A. (Barcelona, Spain), 3i Biomet (Palm Beach, U.S.A.), BTI (Alava, Spain) and Nobel Biocare (Göteborg, Sweden), with standard 4.1 mm heads and external hexagons, and their respective machined prosthetic abutments. The implant-toabutment fit/misfit was evaluated at four points (vestibular, lingual/palatine, mesial and distal) between implants and abutments of the same brand and different brands, with or without mechanical torque, using SEM micrographs at 5000X. Image analysis was performed using NIS-Elements software (Nikon Instruments Europe B.V.). Results: Before applying torque, vertical misfit (microgaps) of the different combinations tested varied between 1.6 and 5.4 microns and after applying torque, between 0.9 and 5.9 microns, an overall average of 3.46±2.96 microns. For manual assembly without the use of mechanical torque, the best results were obtained with the combination of the 3i implant and the BTI abutment. The Nobel implant and Nobel abutment, 3i-3i and BTI-BTI and the combination of 3i implant with BTI or Nobel abutment provided the best vertical fit when mechanical torque was applied. Conclusions: The vertical fits obtained were within the limits considered clinically acceptable. The application of mechanical torque improved outcomes. There is compatibility between implants and abutments of different brand and so their combination is a clinical possibility.Solá-Ruiz, M.; Selva-Otaolaurruchi, E.; Senent-Vicente, G.; González-De-Cossio, I.; Amigó Borrás, V. (2013). Accuracy combining different brands of implants and abutments. Medicina Oral, Patología Oral y Cirugía Bucal. 18:332-336. doi:10.4317/medoral.18137S3323361

In Vitro Analysis of the Removability of Fractured Prosthetic Screws within Endosseous Implants Using Conventional and Mechanical Techniques

Statement of problem: The extraction of fractured abutment screws can be a difficult challenge to overcome. Purpose: To compare the removal capacity, dental implant connection damage, and time required to remove the fractured abutment screws between three drilling techniques and a conventional method. Materials and methods: A total of 180 prefabricated screw-retained abutments were intentionally fractured in internal connection dental implants after being subjected to a cyclic load and a static compression load. Afterwards, three operators randomly removed the fractured abutment screws with the following drilling techniques and a conventional method: A: a conventional technique using an exploration probe and ultrasonic appliance (n = 45), Rhein83® (n = 45); B: Sanhigia® (n = 45); C: Phibo® (n = 45). Two-way ANOVA models were estimated to evaluate the mean time according to the method and operator used. Results: The probability of removal of the screws with mobility was twelve times higher than that of the screws without mobility (OR = 12.4; p p = 0.371). The location of the fractured screw did not affect removal success (p = 0.530). The internal thread of the implant was affected after the removal process in 9.8% of the cases. The mean extraction time was 3.17 ± 2.52 min. The Rhein83® method showed a success rate of 84.4%, followed by the Phibo® and conventional methods (71.1%) and the Sanhigia® method (46.7%). Conclusions: The Rhein83® drilling technique increases the removal probability of fractured abutment screws. The initial mobility of the fragment is also a significant factor in the removal success

In vitro analysis of the removability of fractured prosthetic screws within endosseous implants using conventional and mechanical techniques

2023 Descuentos MDPIStatement of problem: The extraction of fractured abutment screws can be a difficult challenge to overcome. Purpose: To compare the removal capacity, dental implant connection damage, and time required to remove the fractured abutment screws between three drilling techniques and a conventional method. Materials and methods: A total of 180 prefabricated screw-retained abutments were intentionally fractured in internal connection dental implants after being subjected to a cyclic load and a static compression load. Afterwards, three operators randomly removed the fractured abutment screws with the following drilling techniques and a conventional method: A: a conventional technique using an exploration probe and ultrasonic appliance (n = 45), Rhein83® (n = 45); B: Sanhigia® (n = 45); C: Phibo® (n = 45). Two-way ANOVA models were estimated to evaluate the mean time according to the method and operator used. Results: The probability of removal of the screws with mobility was twelve times higher than that of the screws without mobility (OR = 12.4; p < 0.001). The success rate according to the operators did not show statistically significant differences (p = 0.371). The location of the fractured screw did not affect removal success (p = 0.530). The internal thread of the implant was affected after the removal process in 9.8% of the cases. The mean extraction time was 3.17 ± 2.52 min. The Rhein83® method showed a success rate of 84.4%, followed by the Phibo® and conventional methods (71.1%) and the Sanhigia® method (46.7%). Conclusions: The Rhein83® drilling technique increases the removal probability of fractured abutment screws. The initial mobility of the fragment is also a significant factor in the removal success.Depto. de Odontología Conservadora y PrótesisFac. de OdontologíaTRUEpubDescuento UC