ABSTRACT
Objective To evaluate the clinical outcomes of severely resorbed edentulous mandibles with tilted implants and fixed prostheses. Methods Ten patients with severely resorbed edentulous mandibles were en-rolled. Each patient received 4 implants,two posteriors placed tilted implants. Immediate loading of tilted implants were applied in all cases using a fixed provisional prosthesis. All patients were finalized 3-4 months with fixed pros-theses. Results 40/40 implants with initial torque(>35N.cm)were followed 1-1.5 years presenting 100%surviv-al. Conclusion The method of using tilted implants and fixed prostheses in the cases of severely resorbed edentu-lous mandibles can achieve an ideal short-term and medium-term effects.
ABSTRACT
@#To seek convenient and effective method for reconstruction of edentulous jaw, Maló and his colleagues developed All-on-Four implant immediate-function concept. The principle of All-on-Four is to support the full-arch prosthesis by 4 implants and to achieve immediate loading after surgery. Its advantages include avoiding additional bone grafting, evading critical anatomical structures and immediate prosthesis. In recent years, All-on-Four technique has been widely utilized in clinical practice as a viable approach for edentulous patients. With the auxiliary of guided surgery and biomechanical researches, All-on-Four has achieved predictable clinical results. In this paper, the development, investigation of biomechanics and main points of surgery and prosthesis of All-on-Four were briefly reviewed.
ABSTRACT
The aim of this research was to evaluate the load distribution in tilted distal implants used in the all-on-four system. Two implant schemes were used. In both, two vertical anterior implants and tilted posterior implants were installed, one group with an angulation of 15 and another with an angulation of 35. The implants were installed together with a bar binding them all in a photoelastic model obtained from a replica of an edentulous maxilla. In this model, loads were produced in the sector of the bar cantilever, the abutment of the tilted implants and over the four implants using devices specially designed for this purpose. The bands were recorded with a digital camera, and the qualitative and quantitative analyses were carried out by means of student's t-test and the Mann-Whitney test in Biostat v. 5.0, considering a level of p<0.05 to establish a statistically significant relation. In the qualitative analysis, the implant with 35 presented the greatest amount of stress on the cantilever forces at cervical level. The quantitative studies showed fewer differences in all aspects assessed, although significant differences were observed between the two systems when loads were applied at cantilever level. It can be concluded that there are minimal differences in the stress distribution when comparing implants with angulations of 15 or 35. However, there is a greater concentration of stress at the cervical level in implants tilted to 35.
El objetivo de esta investigación fue evaluar la distribución de cargas en implantes angulados distales utilizados en el sistema "All-On-Four". Dos esquemas de implantes fueron empleados. En ambos, dos implantes verticales en el área anterior y dos implantes angulados en el sector posterior fueron instalados, utilizando angulaciones de 15 y 35 o en estos últimos. Los implantes fueron instalados de forma conjunta mediante una barra unida al sistema de resina fotoelástica obtenida de una replica de una maxila edéntula. En este modelo, las cargas fueron producidas en el sector del cantiléver de la barra, el pilar del implante angulado y, mediante un sistema genérico, sobre la totalidad de los implantes. Las bandas de estrés fueron reconocidas en una cámara digital donde los análisis cualitativos y cuantitativos fueron realizados utilizando las pruebas t de Student y Mann-Whitney en el programa computacional Biostat v. 5.0, considerando un valor de p<0,05 para establecer diferencias significativas. En el análisis cualitativo, los implantes con 35 presentaron una gran cantidad de estrés en el área de cantiléver, principalmente a nivel cervical. Los estudios cuantitativos mostraron limitadas diferencias en todos los aspectos, aunque diferencias significativas fueron alcanzadas cuando se compararon ambos sistemas después de la carga a nivel del cantiléver. Se puede concluir que hay diferencias menores en la distribución de estrés cuando se comparan implantes dentales con angulación de 15 y 35. Sin embargo, existe una mayor cantidad de concentraciones de estrés a nivel cervical en los implantes con 35 de angulación.
Subject(s)
Humans , Dental Implants , Dental Stress Analysis , Maxilla/surgery , Stress, Mechanical , Biomechanical Phenomena , Materials Testing/methods , Dental Prosthesis, Implant-SupportedABSTRACT
Biomechanical measurements show that tilted implants, when part of a prosthetic support, avoid the use of distal cantilever units. This study included 20 women (78%) and 12 men (22%), aged over 50 years old (89%), with a total of 156 implants. A delayed occlusal loading protocol was used and the average distal implant length and diameter were 10 mm and 4 mm respectively. Patients were followed up for 2 to 5 years after prosthesis connection. The aims of this study are to analyze the use of tilted implants in prosthetic rehabilitation of maxillae to reduce cantilevers length, and to study the biomechanical implications of implant-bone interface.
Mediciones biomecánicas demuestran que los implantes inclinados, cuando son parte de un soporte de prótesis, evitan el uso de unidades distales en voladizo. Se incluyeron 20 mujeres (78%) y 12 hombres (22%), mayores de 50 años (89%), con un total de 156 implantes. Se utilizó un protocolo de carga oclusal retardada, y la longitud y el diámetro promedios del implante a nivel distal distal, fue de 10 mm y 4 mm, respectivamente. Los pacientes fueron seguidos durante 2 a 5 años después de la conexión de la prótesis. El objetivo de este estudio consiste en analizar el uso de los implantes inclinados en la rehabilitación protésica de maxilares para reducir la longitud de los voladizos, y estudiar las implicaciones biomecánicas de la interfase hueso-implante.
ABSTRACT
Propósito: El objetivo del presente estudio prospectivo es la observación del comportamiento de la función protésica inmediata sobre implantes axiales en combinación con implante inclinados posteriores distribuidos poligonalmente en mandíbulas edéntulas. Material y Métodos: De un grupo de 28 individuos desdentados completos mandibulares se observaron 25 individuos distribuidos en 13 hombres y 12 mujeres con un promedio de edad de 57.8 años, bajo la modalidad de rehabilitación protésica implanto asistida en distribución poligonal de arco completo híbrida con una barra de titanio soldada de sección circular de 2mm de grosor instalada a las 48 hrs. de realizada la inserción de los implantes, la cual a los 3 meses fue cambiado por una estructura colada en titanio como prótesis definitiva. Durante el periodo de observación se evaluó la tasa de éxito implantario, las complicaciones biológicas y mecánicas por un periodo inicial de 1 año. El protocolo se inicia con la valoración y confección de un enfilado dentario de prótesis completa convencional, el que, una vez aceptado por el paciente, es duplicado para la confección de una guía tomográfica, con la cual se procederá a la toma de un scanner dental, relacionado las necesidades protésicas y la distribución implantaria en relación a la emergencia y prolongación del nervio mentoniano, altura del foramen mentoniano y forma de la mandíbula. Todos los pacientes fueron operados elevando un colgajo de espesor total y utilizando la guía quirúrgica All on-4 (Nobel Biocare) bajo sedación endovenosa y utilizando una cubeta multifuncional para la toma de registros maxilomandibulares e implantarios en el proceso de carga imediata...
Purpose: The purpose of this prospective study is the observation of the behaviour of immediate occlusal loading with axial implants in combination with posterior tilted implants in edentulous mandibles polygonally distributed. Methods: From a group of 28 individuals with complete edentulous mandible, 25 individuals distributed in 13 men and 12 women were observed with an average age of 57.8 years, under the implant-assisted prosthetic rehabilitation modality in full arch polygonal hybrid distribution with a welded 2mm-thick titanium bar of circular section installed 48 hrs after insertion of the implant, which was changed after 3 months to a titanium casting structure as definitive prosthesis. During the observation period, the implant success rate, biological and mechanical complications were assessed for an initial period of 1 year. The protocol begins with the assessment and preparation of the lining of a conventional complete denture. Once accepted by the patient, it is doubled to make a tomographic guidance, used to take a dental scanner, The prosthetic needs and implant distribution are related to the emergence and continuation of the mental nerve, mental foramen and height and shape of the jaw. All patients were operated lifting a full-thickness flap and using the All on-4 (Nobel Biocare) surgical guide under intravenous sedation, and a flexible bucket for the maxillomandibular and implant records in the immediate loading...
Subject(s)
Humans , Male , Female , Middle Aged , Jaw, Edentulous/surgery , Immediate Dental Implant Loading/methods , Dental Implants , Jaw, Edentulous/rehabilitation , Dental Implantation, Endosseous/methods , Prospective Studies , Treatment OutcomeABSTRACT
OBJECTIVE: This study aimed to evaluate the bending moments, and compressive and tensile forces in implant-supported prostheses with three, four or five abutments. MATERIAL AND METHODS: Ten Pd-Ag frameworks were tested over two master models with: 1) parallel vertical implants, and 2) tilted distal implants. Strain gauges were fixed on the abutments of each master model to measure the deformation when a static load of 50 N was applied on the cantilever (15 mm). The deformation values were measured when the metallic frameworks were tested over three, four or five abutments, and transformed into force and bending moment values. Data were analyzed by ANOVA and Tukey's test for multiple comparisons at 5 percent level of significance. RESULTS: Abutment #1 (adjacent to the cantilever) had the highest values of force and sagittal bending moment for all tests with three, four or five abutments. Independently from the number of abutments, axial force in abutment #1 was higher in the vertical model than in the tilted model. Total moment was higher with three abutments than with four or five abutments. Independently from the inclination of implants, the mean force with four or five abutments was lower than that with three abutments. CONCLUSION: The results suggest that in the set-ups with four or five abutments tilted distal implants reduced axial force and did not increase bending moments.
Subject(s)
Humans , Dental Abutments , Dental Implants , Dental Prosthesis Design , Dental Prosthesis, Implant-Supported , Analysis of Variance , Biomechanical Phenomena , Compressive Strength , Dental Implantation, Endosseous , Models, Dental , Dental Stress Analysis , Elasticity , Models, Structural , Pliability , Statistics, Nonparametric , Tensile StrengthABSTRACT
Purpose: To assess the magnitude and distribution of axial forces and bending moments in abutments as a function of cantilever length and inclination of implants. Methods: Ten metallic bars simulated frameworks of fixed implant-supported prosthesis over two master models with five implants: one with all implants straight and parallel (n=5) and one with the two distal implants tilted (n=5). Strain gauges were fixed on abutments to measure deformation when a 50N-load was applied on the cantilever at 10, 15, and 20mm-distance from the distal abutment. Deformation values were transformed into axial force and bending moment and analyzed by ANOVA and Tukey test (α = 5%). Results: Comparing 10mm- to 20mm-cantilever, there was an increase of approximately 50% for axial force and of 70% for saggital bending moment. On the abutment adjacent to the cantilever, the axial force in the inclined model was 70% lower than in the straight model, and bending moments did not vary. Conclusion: The results suggest that the inclination of distal implants does not have any deleterious biomechanical effect on abutments of the tested models and may reduce the cantilever effect on force magnitude.
Objetivo: Avaliar a magnitude e a distribuição de forças axiais e momentos fletores em pilares em função da extensão do cantilever e da inclinação dos implantes. Metodologia: Dez barras metálicas simularam infraestruturas de prótese fixa implantossuportada sobre dois modelos mestre com 5 implantes: um modelo com todos os implantes retos e paralelos (n=5) e um com os dois implantes distais inclinados (n=5). Extensômetros foram fixados nos pilares para medir sua deformação quando uma carga de 50N foi aplicada no cantilever a 10, 15 e 20 mm do implante distal. Os valores de deformação foram convertidos em força axial e momento fletor e analisados por ANOVA e teste de Tukey (α = 5%). Resultados: Comparando-se as distâncias de 10 e 20 mm, houve um aumento de aproximadamente 50% da força axial e de 70% do momento fletor sagital. No pilar adjacente ao cantilever, a força axial no modelo com implantes inclinados foi 70% menor que no modelo com implantes retos, e os momentos fletores não variaram. Conclusão: Os resultados sugerem que a inclinação dos implantes distais não promoveu nenhum efeito deletério sobre os pilares nos modelos testados e pode reduzir o efeito do cantilever na magnitude da força.