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Maxillary Overdentures (maxillary + overdenture)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Influence of Attachment Systems on Load Transfer of an Implant-Assisted Maxillary Overdenture

JOURNAL OF PROSTHODONTICS, Issue 4 2004
Mete I. Fanuscu DDS
Purpose: This photoelastic study compared the load transfer characteristics of 2 retention mechanisms in an implant-assisted overdenture prosthesis. Materials and Methods: Four implants were incorporated into a photoelastic model of a moderately resorbed edentulous human maxilla. Two retention mechanisms were studied by changing components on the same model and the palateless overdenture. The retention mechanisms studied were bar splint with anterior clip and distal resilient attachments, and solitary ball/O-ring attachments. Loads, ranging from 1.4 to 14.4 kg, were applied to the palatal incline of central incisors and buccal incline of premolars with and without balancing contacts. Stresses developed around all the implants under each loading condition were photographed in the field of a circular polariscope. Results: With both retention mechanisms, protrusive and laterotrusive loads without balancing contacts caused instability of the overdenture, producing minimal stress around the implants in the supporting structure. High intensity stresses indicating intrusion of the posterior implants were noted when the bar/distal resilient attachment overdenture had balancing contacts for protrusive and laterotrusive loads. The posterior implants of ball/O-ring attachment overdenture exhibited high intensity stresses indicating not only intrusion, but also bending, when the occlusion was balanced. Conclusions: Balanced occlusion was required in both retention mechanisms for stability of the implant-assisted overdenture when clinically acceptable loads were applied. The protrusive and laterotrusive loads were not distributed equitably in either mechanism, since highest stresses occurred at the posterior implants. [source]

Successful outcome of splinted implants supporting a ,planned' maxillary overdenture: a retrospective evaluation and comparison with fixed full dental prostheses

CLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2009
A. Sanna
Abstract Objective: Whereas an overdenture concept is generally accepted for the mandible, the outcome of this therapy for the maxilla remains less documented. This retrospective analysis evaluated the peri-implant parameters of implants supporting a ,planned' overdenture in the maxilla, and compared these data with those of an age-matched control group, with a fixed full dental prosthesis. Material and methods: All patients with an implant-supported overdenture in the maxilla from the Leuven University Hospital (at least 12 months in function) were recalled for a thorough examination. Forty-four patients (162 implants, Brånemark type) could be enrolled. Results: The mean loading time was 9 years (range: >1 to >20 years). The cumulative survival rate after 10 years of function was 99.3% if four to six interconnected implants supported the overdenture, but only 85.7% in case two non-connected implants were used as support. The marginal bone level in the former group remained stable, with changes comparable with those observed for implants supporting fixed full dental prostheses. Conclusions: These results fully support the overdenture treatment concept for the maxilla, at least when ,4 splinted implants are used. [source]

The Milled Bar-Retained Removable Bridge Implant-Supported Prosthesis: A Treatment Alternative for the Edentulous Maxilla

JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 4 2002
DGDP(UK), PAUL A. TIPTON BDS
ABSTRACT Restoration of the edentulous jaw with dental implants can be achieved using either an implant-supported prosthesis, such as a fixed bridge, or an implant-retained prosthesis, such as a traditional overdenture. The implant-retained prostheses use edentulous ridges as primary stress-bearing regions, and through stress-breaking mechanisms, the implants are not loaded during function. However, the success rates of maxillary overdentures do not appear to be as good as for mandibular overdentures; this may be attributable to the adverse loading conditions, short implant length, poor quality of bone, number of implants used, flexible bar design, or poor treatment planning. Many articles have also described the numerous problems and multiple visits required in maintaining a traditional bar-retained overdenture restoration, often making it more expensive in the long term than a fixed restoration. The milled bar implant-supported prosthesis offers the benefits of both fixed and removable restorations. Its infrastructure provides the same rigidity as the fixed restoration, owing to the precise fit to the superstructure, which is removable, to promote adequate access for hygiene, yet it still provides lip support and maintains close contact with the soft tissues. These advantages enhance phonetics, esthetics, correct lip support, maintenance, and patient comfort. CLINICAL SIGNIFICANCE Restoring esthetics and function for the edentulous patient requires a multidiscipline approach for success. This article discusses the techniques for restoring function and esthetics for these patients, using a milled bar restoration supported and retained by dental implants. [source]

Human ex vivo bone tissue strains around immediately loaded implants supporting maxillary overdentures

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2005
vanç Akça
Abstract Purpose: To evaluate ex vivo bone tissue strains around maxillary implants supporting immediately loaded bar-retained overdentures. Material and methods: Ninety degree two-element rosette strain gauges were bonded on the labial bone of four ITI® dental implants placed in the maxillary anterior region of four completely edentulous maxilla of fresh human cadavers. The installation torque value (ITV) of each implant was measured by a custom-made torque wrench and resonance frequency analyses (RFAs) were undertaken. A bar-retained overdenture was fabricated for each cadaver, and two miniature load cells were integrated in the first molar region of the overdentures for controlled loading experiments. Strain measurements were performed at a sample rate of 10 kHz and under a maximum load of 100 N, simultaneously monitored from a computer connected to a data acquisition system. Finally, removal torque values (RTVs) of the implants were measured. Results: RFA values did not mirror ITVs, while RTVs of implants were slightly lower than the ITVs. Any correlation could not be obtained between RFA values and ITVs or RTVs. Maximum strains around loaded implants ranged between ,100 and ,550 ,, under 25,100 N. The axial and lateral strain values of posterior implants of both sides were higher than those of anterior implants under all loads (P<0.05). Conclusion: Because occlusal forces in humans tend to decrease because of age-related factors, maximum strains around immediately loaded implants supporting maxillary overdentures fall within physiologic levels. Résumé Le but de cette étude a été d'évaluer les tensions du tissu osseux ex vivo autour d'implants maxillaires portant des prothèses amovibles retenues sur une barre placée immédiatement après l'insertion des implants. Deux jauges de force en rosette à 90° ont été attachées au côté lingual de l'os de quatre implants dentaires ITI® placés dans la région antérieure du maxillaire de quatre cadavres humains frais aux maxillaires édentées. La valeur du couple de torsion lors de l'installation (ITV) de chaque implant a été mesurée par un couple fabriqué et des analyses de fréquence de résonnance (RFA) ont été faites. Une prothèse retenue par une barre a été fabriquée pour chaque cadavre et deux cellules de charge miniatures ont été intégrées dans la région de la première molaire de ces prothèses pour les expériences de charge contrôlées. Les mesures de force ont été effectuées à un taux d'échantillonnage de 10 kHz et sous une charge maximale de 100 N, suivies simultanément par un ordinateur connectéà un système d'acquisition de données. Finalement les valeurs des couples de torsion à l'enlèvement (RTV) des implants ont été mesurées. Les valeurs RFA n'étaient pas en ligne avec les ITV tandis que les RTV des implants étaient légèrement inférieurs aux ITV. Aucune corrélation n'a pûêtre établie entre les valeurs RFA et ITV ou RTV. Les forces maximales autour des implants chargés s'étalaient de ,100 ,e à,550 ,e sous 25 N à 100 N. Les valeurs des forces axiales et latérales des implants postérieurs des deux côtés étaient supérieures à celles des implants antérieurs sous toutes les charges (P<0.05). Zusammenfassung Ziel: Es war das Ziel dieser Arbeit, an bis vor kurzem vitalen Knochengewebe Spannungen um Oberkieferimplantate zu untersuchen, welche sofortbelastete und stegverankerte Hybridprothesen tragen. Material und Methoden: Auf den labialen Knochen von vier ITI-Implantaten in der vorderen Region des zahnlosen Oberkiefers von vier frisch verstorbenen Menschen klebte man Dehnmessinstrumente an. Man mass den Wert der Eindrehkraft (ITV) jedes einzelnen Implantates mit einem handelsblichen Drehmomentschlssel und fhrte eine Resonanzfrequenzanalyse (RFA) durch. Man stellte fr jede Leiche eine stegverankerte Hybridprothese her und man baute in der Region der ersten Molaren zwei kleine Messgerte ein, die kontrollierte Belastungsexperimente erlaubten. Dehnmessungen fhrte man mit einer Frequenz von 10 kHz und einer maximalen Belastung von 100 N durch, simultan aufgezeichnet von einem mit dem Messsystem verbundenen Komputer. Schliesslich mass man auch die Krfte, die es brauchte um die Implantate wieder auszudrehen (RTV). Resultate: Die RFA wiederspiegelte die ITV-Werte nicht, whrenddem die RTV-Werte der Implantate geringfgig tiefer waren als die ITV-Werte. Man konnte weder zwischen der RFA, den ITV-Werten oder den RTV-Werten eine Korrelation herstellen. Die maximalen Dehnungen um die Implantate erreichte Werte zwischen ,100 E und ,550 E bei einer Belastung zwischen 25 N und 100 N. Die axialen und lateralen Dehnkrfte bei posterioren Implantaten waren unter smtlichen getesteten Belastungen beidseits grsser als diejenigen der anterioren Implantate (P<0.05). Resumen Propósito: Evaluar las tensiones del tejido óseo ex vivo alrededor de implantes maxilares soportando sobredentaduras retenidas por barras con carga inmediata. Material y Métodos: Se pegaron dos indicadores de tensión de roseta de dos elementos de 90° en el hueso labial de cuatro implantes dentales ITI® colocados en la región maxilar anterior de cuatro maxilares completamente edéntulos de cadáveres humanos frescos. Se midió el valor del torque de instalación (ITV) de cada implante por medio de una chicharra de torque hecha a medida y se llevó a cabo análisis de frecuencia de resonancia (RFA). Se fabricó una sobredentadura retenida por barras para cada cadáver y se integraron dos células miniatura de carga en la región del primer molar de las sobredentaduras para los experimentos de carga controlada. Se llevaron a cabo mediciones de la tensión a un índice de muestra de 10 kHz y bajo una carga máxima de 100 N, simultáneamente monitorizada desde un ordenador conectado a sistema de adquisición de datos. Finalmente, se midieron los valores del torque de remoción (RTV) de los implantes. Resultados: Los valores de RFA no se reflejaron en los ITVs, mientras que los RTVs de los implantes fueron ligeramente más bajos que los ITVs. No se pudieron obtener correlaciones entre los valores de RFA y los ITVs o RTVE. Las tensiones máximas alrededor de los implantes cargados variaron entre ,100 ,, y ,550 ,, bajo 25 N a 100 N. Los valores de las tensiones axiales y laterales de los implantes posteriores de ambos lados fueron mayores que aquellos implantes anteriores bajo todas las cargas (P<0.05). [source]