Mandibular two-implant telescopic overdentures Heckmann, Siegfried M.; Schrott, Alexander; Graef, Friedrich ...
Clinical oral implants research,
October 2004, Letnik:
15, Številka:
5
Journal Article
Recenzirano
: To stabilize mandibular overdentures in edentulous patients, various connector types which can be attached to between two and four implants placed in the anterior mandible are possible. Treatment ...using non‐rigid telescopic connectors on two interforaminal implants for overdenture stabilization began in 1989. The objective of this study is to investigate soft‐ and hard‐tissue conditions as well as prosthesis function after a period of 10 years. This also involved an evaluation of correlations between radiographic and clinical parameters. Twenty‐three subjects with 46 interforaminal implants (ITI solid screw implants, 12 mm in length, 4.1 mm in diameter; 10.4 years in situ, range, 8–12.8 years) were investigated. Modified plaque index (mPI), sulcus fluid flow rate (SFFR), modified sulcus bleeding index (mBI), probing depth (PD), distance from implant crown margin to the coronal border of the peri‐implant mucosa (DIM), attachment level (AL), width of keratinized mucosa (KM), Periotest® values (PTVs) and prosthesis function were evaluated. In the radiographic evaluation, the distance between implant shoulder and first crestal bone–implant contact (DIB) in mm and the horizontal bone loss (HBL) in mm were measured. The relatively high mPI scores (mean, 0.82; score, 0 in 44.4%; SD, 0.83) did not result in increased SFFR scores (mean, 12; min, 3, max, 38; SD, 7.43) or higher mBI scores (mean, 0.35; score, 0 in 70.8%; SD, 0.59), which was commensurate with healthy peri‐implant mucosa. A mean PD value of 2.15 mm (min, 1 mm; max, 5 mm; SD, 0.96) and a mean DIM value of 0.28 mm (min, 0 mm; max, 2 mm; SD, 0.52) were measured. The implants were stable, showing a mean Periotest® value of −1.91 (max, 02, min, −6; SD, 1.76). A mean DIB of 3.19±0.95 mm (range, 1.3–5.16 mm) and a mean HBL of 1.6±1.52 mm (range, 0.28–8.33 mm) were calculated. A correlation was found between DIB and the parameters SFFR (P=0.060), DIM (P=0.042), AL (P=0.050) and especially PTV (P<0.01), leading to the assumption that these clinical parameters may be useful indicators of peri‐implant bone loss. The results of the 10‐year follow‐up examination show that non‐rigid telescopic connectors with two interforaminal implants for overdenture stabilization appear to be an efficient and effective long‐term treatment modality in severely resorbed edentulous mandibles. Particularly in geriatric patient treatment this concept may provide advantages in terms of handling, cleaning and long‐term satisfaction.
Résumé
Pour stabiliser les prothèses amovibles mandibulaires chez les patients édentés, différents types de connexion pouvant être attachés entre deux ou quatre implants placés dans la région antérieure sont possibles. Le traitement utilisant des connexions téléscopiques non‐rigides sur deux implants situés entre les trous mentonniers pour la stabilisation de la prothèse a démarré en 1989. Le but de cette investigation a été d'étudier les conditions des tissus mous et durs ainsi que la fonction de la prothèse sur une période de dix années. Cela comprenait également une évaluation des relations entre les paramètres cliniques et radiographiques. Vingt‐trois patients avec 46 implants situés entre les trous mentonniers (implants vis solides ITI, 12 mm de longueur, 4,1 mm de diamètre; 10,4 années in situ, de 8 à 13 années) ont été suivis. L'indice de plaque modifiée (mPI), le taux de fluide créviculaire (SFFR), l'indice modifié de saignement sulculaire (mBI), la profondeur au sondage (PD), la distance de la partie coronaire de l'implant jusqu'au rebord coronaire de la muqueuse paroïmplantaire (DIM), le niveau d'attache (AL), la largeur de la muqueuse kératinisée (KM), les mesures Periotest® (PTV) et le fonctionnement de la prothèse ont étéévalués. Dans l'évaluation radiographique, la distance entre l'épaule implantaire et le premier contact implant‐os crestal (DIB) en mm et la perte osseuse horizontale (HBL) en mm ont également été mesurés. Les scores relativement élevés de MPI (moyenne de 0,82; score 0 dans 44,4% des cas; SD 0,83) ne s'accompagnaient pas de scores plus importants de SFFR (moyenne 12; min 3, max 38; SD 7,43) ou de scores plus élevés de MBI (moyenne 0,35; score 0 dans 71% des cas; SD 0,59), ce qui était en accord avec une muqueuse paroïmplantaire saine. Une valeur PD moyenne de 2,15 mm (min.1 mm, max 5 mm; SD 0,96) et une valeur moyenne DIM de 0,28 mm (min 0 mm, max 2 mm; SD 0,52) ont été mesurées. Les implants étaient stables, montrant une valeur Periotest moyenne de ‐1,91 (max 0,2, min, ‐6, SD 1,76). Une DIB moyenne de 3,19 ±0,95 mm (de 1,30 à 5,16 mm) et un HBL moyen de 1,60±1,52 mm (de 0,28 à 8,33 mm) ont été calculés. Une relation a été constatée entre DIB et les paramètres SFFR (P=0,060), DIM (P=0,0042), AL (P0=0,050) et surtout PTV (P<0,01), portant à croire que ces paramètres cliniques pourraient être des indicateurs utiles de la perte osseuse paroïmplantaire. Les résultats de cet examen de suivi de dix années montrent que les connexions téléscopiques non‐rigides avec deux implants situés entre les trous mentonniers pour la stabilisation des prothèses semblent une modalité de traitement à long terme efficace chez les patients sévèrement édentés. Principalement chez les patients gériatriques ce concept pourrait apporter des avantages en terme de satisfaction à long terme, de nettoyage et de maintien.
Zusammenfassung
Um den zahnlosen Unterkiefer mit Implantaten und Hybridprothesen zu versorgen, stehen verschiedene Verbindungselemente zur Verfügung. Man greift dabei auf eine Anzahl von zwei bis vier Implantaten zurück. Seit 1989 wird ein Konzept verfolgt, bei dem Resilienzteleskope auf zwei interforaminalen Implantaten zur Prothesenstabilisierung herangezogen werden. Gegenstand dieser Studie ist es, die Weich‐ und Hartgewebesituation sowie die Prothesenfunktion nach einem Zeitraum von 10 Jahren zu untersuchen. Weiterhin wurden statistische Korrelationen zwischen klinischen und röntgenologischen Parametern berechnet. 23 Patienten mit 46 interforaminalen Implantaten (ITI‐Vollschraubenimplantate, 12 mm Länge, 4,1 mm Durchmesser; 10,4 Jahre in situ, min. 8,0 Jahre, max. 12,8 Jahre) wurden untersucht. Die klinische Untersuchung umfasste den modifizierten Plaque‐Index (mPI), die Sulkusfluid‐Fließrate (SFFR), den modifizierten Blutungsindex (mBI), die Sondierungstiefe (PD), den Abstand zwischen Implantatschulter und koronaler peri‐implantärer Mukosa (DIM), das klinische Attachment‐Level (AL), die Breite der keratinisierten Mukosa (KM), Periotest®‐Messungen (PTV) und die Beurteilung der Prothesenfunktion. Zur röntgenologischen Auswertung wurden der Abstand zwischen Implantatschulter und erstem krestalem Implantat‐Knochen‐Kontakt (DIB) und der horizontale Knochenabbau (HBL) gemessen. Trotz relativ hoher mPI‐Werte (Mittelwert 0,82; Wert 0 in 44,4%; SD 0,83) blieben die SFFR‐Werte (Mittelwert 12; min. 3, max. 38; SD 7,43) und die mBI‐Werte (Mittelwert 0,35; Wert 0 in 70,8%; SD 0,59) relativ gering, was dem klinischen Bild gesunder peri‐implantärer Weichgewebe entsprach. Es wurden ein mittlerer PD‐Wert von 2,15 mm (min. 1 mm, max. 5 mm; SD 0,96) und ein mittlerer DIM‐Wert von 0,28 mm (min. 0 mm, max. 2 mm; SD 0,52) gemessen. Bei einem durchschnittlichen Periotest®‐Wert von ‐1,91 (max. 02, min. −6; SD 1,76) waren die Implantate als stabil anzusehen. Die röntgenologische Auswertung ergab einen mittleren DIB‐Wert von 3,19±0,95 mm (Bereich 1,30–5,16 mm) und einen mittleren HBL‐Wert von 1,60±1,52 (Bereich 0,28–8,33 mm). Statistisch konnte eine Korrelation zwischen DIB und den Parametern SFFR (p=0,060), DIM (p=0,042), AL (p=0,050) und besonders PTV (p < 0,01) gefunden werden, weshalb diese Parameter eventuell als wertvolle klinische Indikatoren für einen stattfindenden peri‐implantären Knochenabbau herangezogen werden können. Die 10‐Jahres‐Ergebnisse dieser Studie zeigen, dass zwei mit Resilienzteleskopen versorgte Implantate zur Stabilisierung einer Hybridprothese eine langfristig erfolgversprechende Therapiemöglichkeit im stark atrophierten zahnlosen Unterkiefer darstellen. Besonders der Behandlung älterer Patienten kommt dieses Konzept aufgrund einfacher Prothesenhandhabung, guter Hygienefähigkeit und langfristiger Patientenzufriedenheit zugute.
Resumen
Para estabilizar las sobredentaduras mandibulares en pacientes edéntulos, es posible conectar varios tipos de conectores a entre dos y cuatro implantes en la mandíbula anterior. El tratamiento utilizando conectores telescópicos no rígidos en dos implantes interforaminales para la estabilización de la sobredentadura comenzó en 1989. El objetivo de este estudio fue investigar las condiciones de los tejidos duros y blandos además de la función de la prótesis tras un periodo de 10 años. Esto también involucró una evaluación de correlaciones entre parámetros clínicos y radiográficos.
Se investigaron veintitrés sujetos con 46 implantes interforaminales (implantes roscados macizos ITI, 12 mm de longitud, 4.1 mm de diámetro; 10.4 años in situ, rango 8 a 12.8 años). Se evaluaron el índice de placa modificado (mPI), la proporción de flujo de fluido del surco (SFFR), el índice de sangrado del surco modificado (mBI), la profundidad de sondaje (PD), la distancia del margen de la corona al borde coronal de la mucosa periimplantaria (DIM), el nivel de inserción (AL), la anchura de la mucosa queratinizada (KM), las medidas del Periotest® (PTV) y la función protésica. En la evaluación radiográfica, se midió la distancia entre el hombro del implante y el primer contacto implante‐hueso crestal (DIB) en mm y la perdida horizontal de hueso (HBL) en mm. Los valores relativamente altos de mPI (media 0.82; valor 0 en 44.4%; SD 0.83) no resultaron en unos valores aumentados de SFFR (media 12; min. 3, max. 38; SD 7.43) o mayores valores de mBI (media 0.35; valor 0 en 70.8%; SD 0.59), los cuales fueron equivalentes a los de una mucosa periimplantaria sana. Se midieron unos valores medios de PD de 2.15 mm (min. 1 mm, max. 5 mm; SD 0.96)
PARP1 mediates poly-ADP-ribosylation of proteins on chromatin in response to different types of DNA lesions. PARP inhibitors are used for the treatment of BRCA1/2-deficient breast, ovarian, and ...prostate cancer. Loss of DNA replication fork protection is proposed as one mechanism that contributes to the vulnerability of BRCA1/2-deficient cells to PARP inhibitors. However, the mechanisms that regulate PARP1 activity at stressed replication forks remain poorly understood. Here, we performed proximity proteomics of PARP1 and isolation of proteins on stressed replication forks to map putative PARP1 regulators. We identified TPX2 as a direct PARP1-binding protein that regulates the auto-ADP-ribosylation activity of PARP1. TPX2 interacts with DNA damage response proteins and promotes homology-directed repair of DNA double-strand breaks. Moreover, TPX2 mRNA levels are increased in BRCA1/2-mutated breast and prostate cancers, and high TPX2 expression levels correlate with the sensitivity of cancer cells to PARP-trapping inhibitors. We propose that TPX2 confers a mitosis-independent function in the cellular response to replication stress by interacting with PARP1.
Abstract
Background
Intestinal epithelial cells (IECs) are located at the interface between the gut lumen and the underlying mucosal defense system. Here, they play a central role in the coordination ...of intestinal homeostasis, tempering pro-inflammatory responses but remaining rapidly responsive to noxious stimuli such as enteric pathogens. One early response mechanism by which IECs engage in immune defense is through the activation of the inflammasome which mobilizes the inflammatory caspases; caspase-1 and -11.
Aims
Here, we investigated the role of the inflammasome in overall mucosal defense against the enteric pathogen Salmonella enterica serovar Typhimurium.
Methods
Streptomycin-pretreated C57BL/6 (wildtype), Casp1/11 deficient (−/−), Casp1−/− and Casp11−/− mice were orally infected with Salmonella and burdens determined in intestinal tissues at 18h post infection (p.i.).
Results
Increased pathogen loads were observed for all caspase-deficient mice compared to wildtype, which correlated with increased IEC intracellular Salmonella burdens. Interestingly, despite increased bacterial loads, pathology scores for all inflammatory caspase mice were decreased, especially with regard to ‘IEC damage’ and ‘goblet cell loss’.
To determine if the increased burdens were due to the loss of IEC-intrinsic inflammasomes, enteroid monolayers were derived and infected with Salmonella. This revealed significantly increased intracellular burdens in caspase-deficient monolayers as compared to wildtype, in concert with a marked decrease in IEC shedding and cell death. Peak inflammatory caspase activity was displayed in shedding wildtype IECs, suggesting the IEC-intrinsic inflammasome restricts Salmonella infection through infected IEC expulsion.
The role of inflammasome signaling in acute mucosal defense was also examined. Wildtype tissue demonstrated a dramatic increase in mucus thickness (as evaluated by Muc2 immunostaining) and antimicrobial Reg3γ and β lectin transcript levels compared to caspase-deficient mice. Mucin release and Reg3 induction has been previously linked to IL-22, therefore we measured IL-22 expression and observed increased secretion in infected wildtype mice compared to Casp1/11−/−. This correlated with increased cecal infiltration of IL-22 producing ILC3 and NK T-cells. When infected mice were treated with IL-22 neutralizing antibody, this increased Salmonella burdens and decreased infection-induced mucus secretion, while no differences were observed in Casp1/11−/− treated with neutralizing antibody or isotype control.
Conclusions
Therefore the intestinal epithelium utilizes inflammasome signaling to coordinate multiple layers of innate defense at the gut mucosal surface to ultimately restrict enteric pathogen infections and their systemic spread.
Funding Agencies
CCC, CIHR, NRCUBC
Enhancing food security for poor and vulnerable people requires adapting rural food systems to various driving factors. Food security-related research should apply participatory action research that ...considers the entire food value chain to ensure sustained success. This article presents a research framework that focusses on determining, prioritising, testing, adapting and disseminating food securing upgrading strategies across the multiple components of rural food value chains. These include natural resources, food production, processing, markets, consumption and waste management. Scientists and policy makers jointly use tools developed for assessing potentials for enhancing regional food security at multiple spatial and temporal scales. The research is being conducted in Tanzania as a case study for Sub-Saharan countries and is done in close collaboration with local, regional and national stakeholders, encompassing all activities across all different food sectors.
•We propose a framework for food security research on rural food value chains.•The framework includes action research with stakeholders of all food sectors.•The research is conducted in Tanzania at multiple spatial and temporal scales.•We prioritize, test and evaluate upgrading strategies for rural food systems.•Scientists and policy-makers jointly assess potentials for enhancing food security.
It is generally assumed that passively fitting superstructures are a prerequisite for long-lasting implant success. In the study presented, the strain development of three-unit implant fixed partial ...dentures (FPDs) was evaluated at the bone surrounding the implant and on the superstructure using a strain gauge technique. Six groups of three-unit FPDs representing the commonly used techniques of bridge fabrication were investigated with 10 samples each, in order to quantify the influence of impression technique, mode of fabrication and retention mechanism on superstructure fit. Two ITI implants (Straumann, Waldenburg, Switzerland) were anchored in a measurement model according to a real-life patient situation and strain gauges were fixed mesially and distally adjacent to the implants and on the bridge pontics. The developing strains were recorded during cement setting and screw fixation. For statistical analysis, multivariate two sample tests were performed setting the level of significance at P=0.1. None of the investigated bridges revealed a truly passive fit without strains occurring. About 50% of the measured strains were found to be due to impression taking and model fabrication, whereas the remaining 50% were related to laboratory inaccuracies. The two impression techniques used did not reveal any significant differences in terms of precision. Both modes of fixation--i.e. cement and screw retention--provoked equally high stress levels. In the fabrication of screw-retained FPDs, similar results were obtained from the use of burn-out plastic copings and the technique of casting wax moulds to premachined components. Bonding bridge frames onto gold cylinders directly on the implants significantly reduces strain development.
Statement of problem Current copy-milling systems allow for the fabrication of 1-piece zirconia ceramic posts and cores, which can be used in combination with ceramic crowns to restore endodontically ...treated teeth in an esthetic manner. However, limited data are available on the fracture resistance of copy-milled zirconia ceramic posts. Purpose The purpose of this in vitro study was to compare the fracture resistance of prefabricated posts made from zirconia ceramic and fiber-reinforced composite resin with the fracture resistance of copy-milled zirconia ceramic posts. Material and methods Three groups of posts and cores were fabricated (n=10): prefabricated zirconia ceramic posts with composite resin cores (ZIR), fiber-reinforced composite resin posts with composite resin cores (FRC), and copy-milled zirconia ceramic posts and cores (CM). Following artificial aging by thermal cycling and masticatory simulation, compressive tests were performed in a universal testing machine with the posts mounted at an angle of 135 degrees to the long axis of the posts. The maximum forces needed to fracture the posts were recorded for statistical analysis (1-way ANOVA, Tukey's Honestly Significant Difference test; α=.05). Results The mean maximum forces (SD) needed to fracture the posts and cores were 123.10 (19.38) N for FRC, 139.30 (42.70) N for CM, and 267.10 (59.11) N for ZIR. The prefabricated zirconia ceramic posts required significantly higher fracture loads as compared to FRC ( P <.001) and CM ( P <.001). Conclusions The fracture load of copy-milled zirconia ceramic posts is significantly lower than that of prefabricated zirconia ceramic posts of the same size.
Abstract
Background
Intestinal epithelial cells (IECs) are located at the interface between the gut lumen and the underlying mucosal defense system. Here, they play a central role in the coordination ...of intestinal homeostasis, tempering pro-inflammatory responses but remaining rapidly responsive to noxious stimuli such as an enteric pathogen. One mechanism by which IECs engage in innate immune defense is through the activation of the inflammasome which mobilizes the inflammatory caspases; Caspase-1 and -11.
Aims
Here, we investigate the role of the inflammasome in IEC and overall mucosal defense against the enteric pathogen Salmonella enterica serovar Typhimurium SL1344.
Methods
Streptomycin-pretreated wildtype C57BL/6, Casp1/11 deficient (−/−), Casp1−/− and Casp11−/− mice were orally infected and S. Typhimurium burdens determined in intestinal tissues at 18h post infection.
Results
Increased cecal and luminal pathogen loads were observed for all caspase-deficient mice compared to wild type, which correlated with increased IEC intracellular S. Typhimurium burdens. Interestingly, despite increased bacterial loads, cecal pathology scores for all deficient mice were decreased, especially with regard to ‘IEC damage’ and ‘goblet cell loss’.
To determine if the increased burdens were due to the loss of IEC-intrinsic inflammasomes, enteroid monolayers were derived and infected. This revealed significantly increased intracellular burdens in caspase deficient monolayers as compared to wild type, in concert with a marked decrease in IEC sloughing. Peak inflammatory caspase activity was displayed in sloughing wildtype IECs, suggesting IEC-intrinsic inflammasome restricts S. Typhimurium infection through infected IEC expulsion.
To examine the role of inflammasome signaling on mucosal defense, mucin layer thicknesses were evaluated by Muc2 immunostaining. After infection, wild type tissue demonstrated a dramatic increase in mucus thickness while caspase deficient mice displayed only a marginal increase. Similarly, expression of the antimicrobial lectins Reg3γ and β was dramatically increased in infected wildtype mice compared to caspase deficient mice. Since mucin release and Reg3 induction have been previously linked to the cytokine IL-22, and IL-22 expression was increased in infected wildtype mice, we tested the effects of neutralizing IL-22. This revealed increased S. Typhimurium burdens and decreased infection-induced mucin secretion, while no differences were observed in Casp1/11−/− treated with either neutralizing antibody or isotype control.
Conclusions
These results thus indicate that the intestinal epithelium utilizes inflammasome signaling to coordinate multiple layers of innate defense at the gut mucosal surface to ultimately restrict enteric pathogen infections and systemic spread.
Funding Agencies
CCC, CIHRNIH
Abstract
Background
Intestinal epithelial cells (IECs) play a central role in the coordination of intestinal homeostasis. They must strike a careful balance to temper pro-inflammatory responses ...against the intestinal microbiota, while remaining vigilant and rapidly responsive when exposed to a noxious stimulus such as an enteric pathogen. One early response mechanism by which IECs engage in immune defense is through the activation of an IEC-specific inflammasome. This activation triggers the extrusion of infected IEC into the gut lumen, ultimately restricting Salmonella enterica serovar Typhimurium from escaping the gut and spreading systemically. However, it appears the role of the inflammasome in gut defense is not just restricted to IEC shedding but it also plays a key role in mucin secretion and antimicrobial lectin production.
Aims
Here, we investigate the role of the inflammasome in mucosal defense against S. Typhimurium SL1344.
Methods
This study employed a streptomycin pretreatment S. Typhimurium mouse infection model as well as various cell and immunofluorescent staining to characterize the role of the intestinal inflammasome.
Results
Streptomycin-pretreated C57BL/6, Casp1/11 deficient (−/−) and Casp11−/− mice were orally infected and S. Typhimurium loads determined for each respective tissue at 18h and 72h post infection. Increased pathogen burdens were observed for both caspase-deficient mice compared to wild type, with increased systemic spread seen in the mesenteric lymph nodes, liver and spleen at both time points for Casp1/11−/− mice but only at 72h for Casp11 −/−. Interestingly, at 18h, despite increased bacterial loads, cecal pathology scores were decreased in both Casp1/11−/− and Casp11−/− mice, as compared to wild type. This was accompanied by increased intracellular S. Typhimurium immunofluorescence staining. Also, cecal mucin layer thickness, as measured by Alcian Blue as well as MUC2 immunofluorescence staining were similar amongst all mouse strains before infection, but were decreased in both Casp1/11−/− and Casp11−/− mice as compared to wild type after infection. Finally, expression of the antimicrobial lectins REG3γ and REG3β were significantly decreased in Casp11−/− mice as compared to wild type mice and minimal staining for REG3β was observed in both caspase deficient mice.
Conclusions
These results indicate that the gut epithelium utilizes inflammasome signaling to coordinate multiple layers of innate defense at the gut mucosal surface to ultimately restrict enteric pathogen infections and systemic spread.
Funding Agencies
CCC, CIHRNSERC, UBC
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