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Extraction Sites (extraction + site)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Orthodontic movement in bone defects augmented with Bio-Oss®

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 1 2001
An experimental study in dogs
Abstract Objective: To study if it was possible to move, by orthodontic means, a tooth into an area of the jaw that had been augmented with Bio-Oss®. Material and Methods: 5 beagle dogs were used. The 1st, 2nd, and 4th mandibular premolars on each side were removed. The defect at the left 4th premolar site was filled with a biomaterial (Bio-Oss®) while the corresponding defect in the right side was left for spontaneous healing. 3 months later, an orthodontic device was inserted in each side of the mandible. The device was designed to allow distal, bodily movement of the 3rd premolars. When the experimental teeth had been moved into the extraction sites of the 4th premolars, the animals were sacrificed and biopsies of the premolar-molar regions of the mandible sampled. The tissues were prepared for histological analysis using standard procedures. In the sections, 3 zones were identified: zone A=the bone tissue within the distal portion of the previous extraction site (4th premolar), zone B=the pressure side of the 3rd premolar, zone C=the tension side of the 3rd premolar. The area occupied by mineralized bone, Bio-Oss® particles and bone marrow was determined by a point counting procedure. The width of the periodontal ligament as well as the percentage of the root surface (in zone B) that exhibited resorption was determined. Results: The findings demonstrated that it was possible to move a tooth into an area of an alveolar ridge that 3 months previously had been augmented with a biomaterial. It was also demonstrated that 12 months after grafting, Bio-Oss® particles remained as inactive filler material in the not utilized part of zone A. The biomaterial was not present in zone C but present in small amounts in zone B. Conclusion: During the orthodontic tooth movement the graft material (Bio-Oss®) was degraded and eliminated from the part of the alveolar ridge that was utilized for the experiment. In the non-utilized part of the ridge the biomaterial, however, remained as a seemingly inactive filler material. [source]

Political, Environmental and Business Aspects of Bulk Water Exports: A Canadian Perspective

CANADIAN JOURNAL OF ADMINISTRATIVE SCIENCES, Issue 1 2006
Farah El Ayoubi
Abstract The issue of exporting water in bulk raises debate among political, economic, environmental, and nationalist groups, particularly in Canada. This research examines bulk water exports by investigating their feasibility as businesses. A hypothetical project was devised for the Annapolis Valley in western Nova Scotia, Canada. The Valley's demographics, climate, and economy were analyzed and its watersheds were studied to better choose a water extraction site. A potential target market was chosen,Brownsville, Texas. Then, a design for the project was proposed using very large crude carriers (VLCC) and the relevant costs were identified. Next, the costs were analyzed in a breakeven analysis. The calculations determined that such a venture is unprofitable by a factor of four times which explains the scarcity of such projects. Résumé La question de l'exportation de l'eau en gros soulève discussion dans les milieux politiques, économiques, écologiques et nationalistes. surtout au Canada. Cette étude en examine la faisabilité commerciale. Un projet hypothétique est conçu, avec pour site la Vallée d'Annapolis, située dans l'ouest de la Nouvelle-Écosse, au Canada. Les données démographiques, le climat et l'économie de la Vallée sont analysés et sa ligne de partage des eaux étudiée dans le but de mieux choisir le site d'extraction. La ville de Brownsville au Texas est le marché hypothétique retenu. Un plan contenant un devis estimatif est proposé. Pour exporter l'eau, on se servira de grands transporteurs de brut (VLCC). Les calculs indiquent qu'une telle entreprise est quatre fois peu rentable, d'oú la rareté de tels projets. [source]

Hard tissue alterations after socket preservation with additional buccal overbuilding: a study in the beagle dog

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 10 2009
Stefan Fickl
Abstract Objectives: The aim of this study was to histometrically assess alterations of the ridge following socket preservation alone and socket preservation with additional buccal overbuilding. Material and Methods: In five beagle dogs four extraction sites were randomly subjected to one of the following treatments: Tx 1: The socket was filled with BioOss Collagen® and covered with a free gingival graft from the palate. Tx 2: The buccal bone plate was augmented using the GBR-technique, the socket was filled with BioOss Collagen® and covered with a free gingival graft. Tx 3: The buccal bone plate was forced into a buccal direction using a manual bone spreader. The socket was filled with BioOss Collagen® and covered with a free gingival graft from the palate. Tx 4: The socket was filled with BioOss Collagen® and a combined free gingival/connective tissue graft was used to cover the socket and for buccal tissue augmentation. For each experimental site, two histological sections were subjected to histometric analysis and evaluated for (i) vertical bone dimensions and (ii) horizontal bone dimensions. Results: All treatment groups showed horizontal and vertical bone loss. The mean vertical bone loss of the buccal bone plate was significantly lower in Tx 4 than in the other groups, while no statistical significant differences could be detected among the groups in the horizontal dimension. Conclusion: Overbuilding the buccal aspect in combination with socket preservation does not seem to be a suitable technique to compensate for the alterations after tooth extraction. [source]

The critical-size supraalveolar peri-implant defect model: characteristics and use

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2006
Ulf M. E. Wikesjö
Abstract Objective: Novel implant technologies and reconstructive therapies for alveolar augmentation require pre-clinical evaluation to estimate their biologic potential, efficacy, and safety before clinical application. The objective of this report is to present characteristics and use of the critical-size, supraalveolar, peri-implant defect model. Methods: Bilateral extraction of the mandibular premolars was performed in 12 Hound Labrador mongrel dogs following horizontal surgical cut-down of the alveolar ridge approximating 6 mm. Each jaw quadrant received three custom-produced TiUniteÔ, ,4.0 × 10 mm threaded implants placed into osteotomies prepared into the extraction sites of the third and fourth premolars. The implants exhibited a reference notch 5 mm from the implant platform to facilitate surgical placement leaving 5 mm of the implant in a supraalveolar position, and to serve as a reference point in the radiographic, histologic and histometric analysis. The implants were submerged under the mucoperiosteal flaps for primary intention healing. Fluorescent bone markers were administered at weeks 3 and 4 post-surgery, and pre-euthanasia. The animals were euthanized following an 8-week healing interval when block biopsies were collected for analysis. Results: Healing was generally uneventful. The radiographic and histometric evaluations demonstrate the limited osteogenic potential of this defect model. Whereas lingual peri-implant sites exhibited a mean (±SE) bone gain of 0.4±0.1 mm, resorption of the buccal crestal plate resulted in a mean bone loss of 0.4±0.2 mm for an overall osteogenic potential following sham-surgery averaging 0.0±0.1 mm. Overall bone density and bone,implant contact in the contiguous resident bone averaged 79.1±1.1% and 76.9±2.3%, respectively. Conclusion: The results suggest that the critical-size, supraalveolar, peri-implant defect model appears a rigorous tool in the evaluation of candidate technologies for alveolar reconstruction and osseointegration of endosseous oral implants. Limited innate osteogenic potential allows critical evaluation of osteogenic, osteoconductive, or osteoinductive technologies in a challenging clinical setting. [source]

Orthodontic movement in bone defects augmented with Bio-Oss®

LEAD ISOTOPE ANALYSES OF BRONZE AGE COPPER-BASE ARTEFACTS FROM AL-MIDAMMAN, YEMEN: TOWARDS THE IDENTIFICATION OF AN INDIGENOUS METAL PRODUCTION AND EXCHANGE SYSTEM IN THE SOUTHERN RED SEA REGION,

ARCHAEOMETRY, Issue 4 2009
L. WEEKS
The results of the lead isotope analysis (LIA) of 15 copper-base artefacts from the Bronze Age site of al-Midamman, Yemen, are reported. The LIA data suggest the existence of an indigenous Bronze Age metal production and exchange system centred on the southern Red Sea region, distinct from those in neighbouring regions of Arabia and the Levant. These preliminary results are highly significant for the archaeology of the region, suggesting that local prehistoric copper extraction sites have thus far gone unrecorded, and highlighting the need for systematic archaeometallurgical fieldwork programmes in the countries surrounding the southern Red Sea. [source]

A prospective clinical study of non-submerged immediate implants: clinical outcomes and esthetic results

CLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2007
Stephen T. Chen
Abstract Objectives: To evaluate healing of marginal defects in immediate transmucosal implants grafted with anorganic bovine bone, and to assess mucosal and radiographic outcomes 3,4 years following restoration. Material and methods: Thirty immediate transmucosal implants in maxillary anterior extraction sites of 30 patients randomly received BioOssÔ (N=10; BG), BioOssÔ and resorbable collagen membrane (N=10; BG+M) or no graft (N=10; control). Results: Vertical defect height (VDH) reductions of 81.2±5%, 70.5±17.4% and 68.2±16.6%, and horizontal defect depth (HDD) reductions of 71.7±34.3%, 81.7±33.7% and 55±28.4% were observed for BG, BG+M and control groups, respectively, with no significant inter-group differences. Horizontal resorption was significantly greater in control group (48.3±9.5%) when compared with BG (15.8±16.9%) and BG+M (20±21.9%) groups (P=0.000). Ten sites (33.3%) exhibited recession of the mucosa after 6 months; eight (26.7%) had an unsatisfactory esthetic result post-restoration due to recession. Mucosal recession was significantly associated (P=0.032) with buccally positioned implants (HDD 1.1±0.3 mm) when compared with lingually positioned implants (HDD 2.3±0.6 mm). In 19 patients followed for a mean of 4.0±0.7 years, marginal mucosa and bone levels remained stable following restoration. Conclusion: BioOssÔ significantly reduced horizontal resorption of buccal bone. There is a risk of mucosal recession and adverse soft tissue esthetics with immediate implant placement. However, this risk may be reduced by avoiding a buccal position of the implant in the extraction socket. [source]

Soft and hard tissue assessment of immediate implant placement: a case series

CLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2007
Gintaras Juodzbalys
Abstract Objectives: The aim of this prospective study was to evaluate clinically and radiographically the success and esthetic result of immediate implant placement at the time of extraction. Material and methods: Twelve patients with 14 titanium screw-shaped implants (13,16 mm length and 4.3 or 5 mm diameters) were placed in the extraction sockets. Defects after implant placement were recorded, and then filled up with deproteinized bovine bone mineral, bioabsorbable collagen membrane, and absorbable pins. The defect was again re-evaluated at second-stage surgery. Clinical and radiographic parameters of the peri-implant conditions were assessed at the moment of prosthesis placement and at 1-year follow-up. Results: The cumulative implant survival and success rate was 100% after a 1-year observation period. Analysis of the esthetic result showed that the mean pink esthetic score (PES) was 11.1 (SD 1.35) at 1-year follow-up. At 1 year, 64.3% papillae had a score of 2 and the remaining 35.7% score 3 according to the Jemt (1997) papillary index. Optimal value of width of the keratinized mucosa was recorded in 13 (92.9%) implant cases in both periods of follow-up. At 1-year follow-up, the linear distance between implant-shoulder to the bone peaks remains stable with a mean of 2.62±0.2 mm at the mesial and 2.9±0.58 mm at the distal aspect. Conclusion: Careful evaluation of potential extraction sites before immediate implant installation promotes optimal implant esthetics. [source]

Modeling of the buccal and lingual bone walls of fresh extraction sites following implant installation

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2006
Mauricio G. Araújo
Abstract Objective: To determine whether the reduction of the alveolar ridge that occurs following tooth extraction and implant placement is influenced by the size of the hard tissue walls of the socket. Material and methods: Six beagle dogs were used. The third premolar and first molar in both quadrants of the mandible were used. Mucoperiostal flaps were elevated and the distal roots were removed. Implants were installed in the fresh extraction socket in one side of the mandible. The flaps were replaced to allow a semi-submerged healing. The procedure was repeated in the contra later side of the mandible after 2 months. The animals were sacrificed 1 month after the final implant installation. The mandibles were dissected, and each implant site was removed and processed for ground sectioning. Results: Marked hard tissue alterations occurred during healing following tooth extraction and implant installation in the socket. The marginal gap that was present between the implant and the walls of the socket at implantation disappeared as a result of bone fill and resorption of the bone crest. The modeling in the marginal defect region was accompanied by marked attenuation of the dimensions of both the delicate buccal and the wider lingual bone wall. Bone loss at molar sites was more pronounced than at the premolar locations. Conclusion: Implant placement failed to preserve the hard tissue dimension of the ridge following tooth extraction. The buccal as well as the lingual bone walls were resorbed. At the buccal aspect, this resulted in some marginal loss of osseointegration. [source]

Partial generation of periodontal ligament on endosseous dental implants in dogs

CLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2005
Leila Jahangiri
Abstract Objectives: The objective of this pilot study was to investigate the feasibility of periodontal ligament (PDL) generation on an implant surface by approximating a tooth-to-implant contact using orthodontics. Methods: Maxillary second premolars of six beagle dogs were extracted bilaterally. After 2 weeks of healing, hydroxyapatite (HA) coated titanium implants, 5 mm in length and 3.3 mm in diameter, were placed in the extraction sites. One side of the arch was used as control. Orthodontic tooth movement was initiated following implant placement to tip the first premolar roots into contact with the implant. This was achieved in 4,6 weeks as confirmed radiographically. Tooth-to-implant contact was maintained for further 6 weeks after which time, teeth were separated from implant contact orthodontically. After further 2 weeks of stabilization, the animals were sacrificed. Samples were analyzed by Faxitron radiographs before histology. Histology samples were prepared with Stevenel's Blue and Van Gieson stain and were subjected to polarized light microscopy. Results: Histologic analysis revealed transfer and formation of PDL-like structure with formation of cellular cementum on the implant surfaces, in four out of six animals, where tooth-to-implant contact had been achieved. Direct bone-to-implant contact was noted in the areas coronal to the PDL-like tissue, an important sign to distinguish between PDL-like tissue and connective tissue that could originate from the coronal portion of a failing implant. Additionally, at the site of contact, the implant surface revealed some resorption of the HA coating. Conclusion: An animal model was established in which the proximity of tooth-to-implant contact lead to partial generation of PDL on a bioactive implant surface in four out of six animals. Résumé L'objectif de cette étude pilote a été d'analyser la possibilité d'obtenir une régénération du ligament parodontal (PDL) sur une surface implantaire en rapprochant le contact implant-dent par l'orthodontie. Les deuxièmes prémolaires maxillaires de six chiens beagle ont été avulsées bilatéralement. Après deux semaines de guérison, des implants en titane recouverts d'hydroxyapatite de 5 mm de long et de 3,3 mm de diamètre ont été insérés dans les sites d'avulsion. Un site de chaque arche était utilisé comme contrôle. Le mouvement orthodontique de la dent était initialisé après le placement de l'implant pour mettre en contact les raçines des premières prémolaires avec l'implant. Ceci a été réalisé en quatre à huit semaines comme l'a confirmé la radiographie. Le contact dent-implant a été maintenu pour une durée supplémentaire de six semaines après lesquelles les dents ont été séparées du contact des implants de manière orthodontique. Après deux semaines de stabilisation, les animaux ont été euthanasiés. Les échantillons ont été analysés par radiographie Faxitron avant l'histologie. Les échantillons histologiques ont été préparés par les colorations du Bleu de Stevenel et de Van Gieson et ont été analysés au microscope optique à polarisation. L'histologiea révélé un transfert et une formation d'une structure ressemblant à PDL avec la formation d'un cément cellulaire à la surface des implants chez quatre des six animaux chez lesquels le contact dent-implant avaient été réalisés. Le contact direct os-implant a été noté dans les zones coronaires au tissu qui ressemblait à PDL, un signe important pour distinguer le tissu ressemblant à PDL et le tissu conjonctif qui pouvait provenir de la portion coronaire de l'implant qui échoue. De plus, au site de contact, la surface implantaire révélait quelques résorptions du recouvrement d'hydroxyapatite. Un modèle animal a donc étéétabli dans lequel la proximité du contact dent-implant était suivie d'une génération partielle de PDL sur une surface implantaire bioactive chez quatre des six animaux. Zusammenfassung Ziele: Das Ziel dieser Pilotstudie war, zu untersuchen, ob es möglich sei, ein parodontales Ligament (PDL) auf einer Implantatoberfläche durch Herstellung eines Zahn-Implantat-Kontakts mittels Orthodontie zu generieren. Methoden: Bei sechs Beagle-Hunden wurden bilateral die zweiten Prämolaren extrahiert. Nach einer Abheilzeit von zwei Wochen wurden Hydroxyapatit beschichtete Titanimplantate mit einer Länge von 5 mm und einem Durchmesser von 3.3 mm in die Extraktionsstellen eingesetzt. Eine Seite des Zahnbogens diente als Kontrolle. Nach der Implantatplatzierung wurde mit der orthodontischen Zahnbewegung begonnen, um die Wurzeln der ersten Prämolaren in Kontakt mit den Implantaten zu bringen. Es wurde radiologisch bestätigt, dass dies nach 4,6 Wochen erreicht wurde. Der Zahn-Implantat-Kontakt wurde für weitere sechs Wochen belassen, danach wurden die Zähne wieder orthodontisch vom Kontakt mit den Implantaten separiert. Nach weiteren zwei Wochen zur Stabilisierung wurden die Tiere geopfert. Die Proben wurden vor der Histologie mittels Faxitron Röntgen analysiert. Die histologischen Proben wurden mit Stevenel`s Blau und van Gieson Färbungen bearbeitet und durch Lichtmikroskopie mit polarisiertem Licht untersucht. Resultate: Die histologische Analyse zeigte einen Transfer und eine Formation von Parodontalligament ähnlichen Strukturen mit der Bildung von zellulärem Zement auf der Implantatoberfläche bei 4 von 6 Tieren, bei welchen ein Zahn-Implantat-Kontakt erreicht worden war. Koronal des PDL-ähnlichen Gewebes bestand ein direkter Knochen-Implantat-Kontakt. Dies war ein wichtiges Merkmal, um zwischen PDL-ähnlichem Gewebe und Bindegewebe, welches vom koronalen Anteil eines fehlgeschlagenen Implantats stammen könnte, zu unterscheiden. Zusätzlich zeigten die Implantatoberflächen im Bereich der Berührungsfläche etwas Resorption der Hydroxyapatit Beschichtung. Schlussfolgerung: Es wurde ein Tiermodell etabliert, in welchem ein Zahn-Implantat-Kontakt bei 4 von 6 Tieren zu einer partiellen Generation eines PDL auf einer bioaktiven Implantatoberfläche führte. Resumen Objetivos: El objetivo de este estudio piloto fue investigar la viabilidad de generación de ligamento periodontal (PDL) en la superficie de un implante por aproximación de un contacto diente a implante usando ortodoncia. Métodos: Se extrajeron los segundos premolares de seis perros beagle bilateralmente. Tras dos semanas de cicatrización, se colocaron en los lugares de extracción implantes de titanio cubiertos de hidroxiapatita, de 5 mm de longitud y 3.3 mm de diámetro. Un lado del arco se usó como control. El movimiento dental ortodóntico se inició tras la colocación del implante para apuntar las raíces del primer premolar hacia el contacto con el implante. Esto se logró en 4-6 semanas tal como se confirmó radiograficamente. El contacto diente a implante se mantuvo durante seis semanas mas tras lo cual, los dientes se separaron del contacto con el implante ortodonticamente. Tras dos semanas más de estabilización, los animales se sacrificaron. Las muestras se analizaron por medio de radiografías Faxitron antes de la histología. Las muestras histológicas se prepararon con azul de Stevenel y tinción de Van Gieson y se sometieron a microscopio de luz polarizada. Resultados: El análisis histológico reveló transferencia y formación de estructuras tipo ligamento periodontal con formación de cemento celular en las superficies del implante, en 4 de 6 animales, en los que se logró el contacto diente a implante. Se notó contacto en las áreas coronales al tejido tipo PDL, un signo importante para distinguir tejido tipo PDL y tejido conectivo que se podría originar de la parte coronal de un implante en vías de fracaso. Además, en el lugar del contacto, la superficie del implante reveló algo de reabsorción de la cubierta de hidroxiapatita. Conclusión: Se estableció un modelo animal en el que la proximidad del contacto diente a implante llevó a la generación parcial de PDL en una superficie de implante bioactiva en 4 de 6 animales. [source]