RESUMEN
Overdenture as a treatment modality for both partially and fully edentulous patients is costeffective and less expensive.The purpose of the present study was to examine the newly fabricated attachments by comparing them with conventional O-ring attachment in vitro in terms of retention force and cyclic aging resistance.A total of 150 samples were prepared and divided into five groups according to the materials used (O-ring attachment,Deflex M10 XR,Deflex Classic SR,Deflex Acrilato FD,and flexible acrylic resin).The retention force of different attachments was measured by a mini dental implant after three subsequent aging (0,63,and 126) cycles in the circumstances similar to the oral environment.The gap space between the head of the implant and the inner surface of the attachments was detected.Two-way analysis of variance (ANOVA) analysis with multiple comparisons test was applied for statistical analysis.The results showed that Deflex M10 XR had the highest retention force and the lowest gap space after cyclic aging;in addition,by comparing the relative force reduction,the lowest values were obtained in the O-ring attachment and the highest values in the flexible acrylic resin attachment.The retention force measured after cyclic aging for the Deflex M10 XR attachment was greatly improved when compared with the O-ring attachment and other types of attachment materials;in addition,the Deflex M10 XR attachment exhibited the minimum gap space between the inner surface and the mini dental implant head.In conclusion,Deflex M10 XR has the ability to withstand weathering conditions and retains its durable and retentive properties after aging when compared with other attachments.
RESUMEN
A minimum insertion torque has been suggested for immediate function of regular diameter implants. Even when there is a growing tendency to use Mini Dental Implants (MDIs) for immediate function of dentures, there is no clinical data concerning MDIs insertion torque, nor its influence on implant failure. The aim of this prospective study was to assess the insertion torque of immediate loaded MDIs in edentulous patients and its association with risk failure. Ninety MDIs were placed in the anterior mandible of 45 edentulous patients, two per patient. The insertion torque was recorded with an electronic device and failures were documented during two years follow-up. All implants were immediately loaded with overdentures, using ball (44/90) or bar (46/90) attachments. A KaplanMeier survival probability estimator and a fitted multiple Cox regression model were performed to establish the influence of insertion torque and other clinical parameters on implant risk failure. The average insertion torque of 90 MDIs was 12.5±7.8 Ncm. A cumulative survival rate of 94.2% (5/90) was found by means of the Kaplan-Meier estimation. The Cox proportional-hazards regression model showed no association between insertion torque and MDIs failure. MDIs have much lower insertion torque than average conventional implants. The insertion torque of MDIs immediately loaded with mandibular dentures, seems not to be a risk factor associated to failure, at two years follow-up.
Un mínimo torque de inserción ha sido sugerido para realizar carga inmediata de implantes de diámetro regular. Aún cuando existe una tendencia creciente a utilizar Mini Implantes Dentales (MID) para la función inmediata de las prótesis totales, no hay datos clínicos relativos a los valores de torque de inserción de estos, ni tampoco de su influencia en el fracaso del implante. El objetivo de este estudio prospectivo fue evaluar el torque de inserción de mini implantes dentales con carga inmediata en pacientes desdentados y su asociación con el riesgo de fracaso. Noventa MIDs fueron colocados en la mandíbula anterior de 45 pacientes desdentados, dos por paciente. El torque de inserción fue obtenido con un dispositivo electrónico y los fracasos fueron documentadas a dos años de seguimiento. Todos los implantes fueron cargados inmediatamente con sobredentaduras, usando un sistema de retención de bola (44/90) o barra (46/90). Se utilizó el estimador de probabilidad de sobrevida de Kaplan-Meier y el modelo riesgos proporcionales de Cox ajustado para establecer la influencia de torque de inserción y otros parámetros clínicos sobre el riesgo de fracaso del implante. El promedio de torque de inserción de 90 MIDs fue 12,5±7,8 Ncm . Los MIDs mostraron a través de la estimación de Kaplan-Meier, una tasa de supervivencia acumulada de 94,2% (5/90). El modelo de riesgos proporcionales de Cox reveló que no existe asociación entre el valor de torque de inserción y el fracaso MIDs. MIDs tienen un valor de torque de inserción mucho más bajo que los implantes convencionales. El torque de inserción de MIDs cargados inmediatamente con prótesis mandibulares, no parece ser un factor de riesgo asociado al fracaso, a dos años de seguimiento.
RESUMEN
Aim of the study : The aim of the study was to check the stress absorbed by the bone around mini over-denture dental implant with and without acrylonitrile O-ring under two different loading conditions. The initial stress absorbed by the implant plays a significant role in the success of the immediate loading implants. Materials and Methods: A three-dimensional finite element analysis using Pro-E mechanica finite element software was used to check the stress absorbed by the bone with and without acrylonitrile O-ring. The implant and the mandible where modeled from the data obtained from C.T. scan and optical projector using reverse engineering process. Two different loading conditions of 80 N and 220 N were determined and the analysis was done. Results: The result showed at lower loads (80 N), there was not much difference in the stress absorbed by the cancellous bone with or without acrylonitrile O-ring, but at higher loads (220), there was difference in the stress absorbed by the cancellous bone with (0.03508 Mpa) and without acrylonitrile O-ring (3.874 Mpa) which showed that significant stress was absorbed by the acrylonitrile O- ring. Conclusion: This study proves that higher loads during parafunctional movement were absorbed by the acrylonitrile O-ring increasing the success of the implants.
RESUMEN
Previously,the choice of prosthetic implant-retained overdentures has depended on data from previous studies about the retention-fatigue strength of the attachment system selected.Little or no data have been available on the correlation between the attachment system selected and the overdenture support configuration.The purpose of the present study was to evaluate the retention force and fatigue resistance of three attachment systems and four support designs of overdenture prosthesis.Four lower edentulous acrylic models were prepared and eight combinations of attachments groups were investigated in the study.These included:O-Rings with mini-dental implants (MDIs),Dalbo elliptic with Dalbo Rotex and fabricated flexible acrylic attachments with both MDI and Dalbo Rotex.The study was divided into four test groups:groups A and B,controls,and groups C and D,experimental groups.Control group A contained three overdenture supports:two free standing MDIs in the canine region and at the midline,and one simulated tooth root with Dalbo Rotex screwed in.Control group B contained four overdenture support foundations:two free standing MDIs in the right canine region and the first premolar region,and two simulated tooth roots with Dalbo Rotex screwed in at the same MDI position,but on the left side of the model.Experimental group C contained three overdenture support foundations:two free standing MDIs in the canine region and at the midline,and one simulated tooth root with MDI screwed in.Experimental group D contained four overdenture support foundations:two free standing MDIs in the right canine region and the first premolar region,and two simulated tooth roots with MDIs screwed in at the same MDI position,but on the left side of the model.Each group was further divided into two subgroups according to attachment type used.Five samples were prepared for each group.Retention force (N) values were recorded initially (0 cycles) and after 360,720,1440 and 2880 insertion and removal cycles.During the tensile test a cross-head speed of 10 mm/min was applied.Values of absolute force (AF) and relative force (RF) were statistically analyzed by two-way ANOVA and multiple comparison Tukey's tests between groups and cycles periods.The results of fatigue tests showed a 50％ reduction in retention force in the subgroups with flexible attachments.A triangular design of overdenture support foundations with O-Ring attachments revealed the lowest value of AF and a relatively high reduction in RF.The four overdenture support designs with flexible acrylic attachments improved the retention force and reduced the fatigue retention.Furthermore,the results of the investigation demonstrate that flexible acrylic attachments for both teeth and implant-supported overdentures offer a wide range of retention forces.
RESUMEN
PURPOSE: In cases when implant supported overdenture is made by using standard size implant, additional procedure such as bone surgery and bone grafting can be required. And it gives burden to doctor and patient in terms of cost. Therefore, it is necessary to find the implant therapy for the edentulous patients in making denture with accordable cost and simple procedure. MATERIALS AND METHODS: Edentulous patients with upper and lower dentures participated in this study. Before the operation, survey about patient's satisfaction to the existing dentures was carried out. Surgical procedures included four small diameter implants installation anterior area and immediate loading. One and three month after the procedure, the same survey about patient's satisfaction was carried out, and radiography was taken. RESULTS: We are doing research to the nine patients. Survival rate is 97.2 percent. The comparison of patient's satisfaction before and after surgery is performed based on oral health impact profile 49. We analyze mainly with masticatory discomfort, retention, aesthetics, social problem, psychological discomfort problems. As a result, satisfaction level is increased at all factors. Retention is the most increased satisfactory factor followed by mastication difficulty, pronunciation, psychological discomfort, social discomfort, aesthetics in order. Marginal bone loss is 0.21 mm at 12 weeks after implant placement. CONCLUSION: This research reveals that the denture supported by mini dental implant increases patient's satisfaction. This study will be continued with more patients for a long time and we are scheduled for taking additional radiography to check whether peri-implant bone resorption occurs or not.