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Mandibular Premolar Teeth (mandibular + premolar_tooth)
Selected AbstractsAnomalous mandibular premolars: a mandibular first premolar with three roots and a mandibular second premolar with a C-shaped canal systemINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2008B. M. Cleghorn Abstract Aim, To describe unusual variations in the root morphology and root canal systems of mandibular first and second premolar teeth extracted for orthodontic reasons. Summary, Normally mandibular first and second premolar teeth have single roots with single canals. A 15-year-old patient presented for orthodontic treatment and two mandibular premolar teeth were examined post-extraction. The mandibular first premolar exhibited three distinct, separate roots and the mandibular second premolar exhibited a C-shaped root canal system. The coronal morphology of each of the mandibular premolars revealed dimensions and anatomy within normal limits. The incidence of a three-rooted mandibular first premolar is approximately 0.2%. Key learning points ,,Thorough clinical and radiographic interpretation is important in recognizing anomalous root and root canal systems. ,,The most common forms of root and canal systems and its aberrations must be understood to realize variations from normal do occur. ,,Successful root canal treatment requires an accurate diagnosis of the root canal system using all available aids. ,,Value of microcomputed tomography in the study of anatomy ex vivo and cone-beam tomography in clinical endodontics of complex premolar cases is increasing. [source] Effectiveness of different techniques for removing gutta-percha during retreatmentINTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2005A. V. Masiero Abstract Aim, To evaluate the effectiveness of various techniques for removing filling material from root canals in vitro. Methodology, Eighty extracted mandibular premolar teeth were selected for the study. The teeth were root filled using thermomechanical compaction of gutta-percha. After 8 months, the filling material was removed and canals were reinstrumented using the following techniques: group I , hand instrumentation with K-type files (SybronEndo, Orange, CA, USA); group II , K3 Endo System (SybronEndo); group III , M4 system (SybronEndo) with K-type files (SybronEndo); and group IV , Endo-gripper system (Moyco Union Broach, York, PA, USA) with K-type files (SybronEndo). The amount of filling debris remaining on root canal walls was assessed radiographically; the images were digitized and analysed using AutoCAD 2000 software. Total canal area, area of the cervical, middle and apical thirds, and area of remaining filling material were outlined by one operator. The ratios between these areas were calculated as percentages of remaining debris. Thereafter, data were analysed by means of one-way anova and the post-hoc Duncan test to identify differences between the four techniques. Results, Multiple comparisons of the percentages of remaining filling material in the entire canal did not reveal any significant differences between the methods of removal. However, when each third was analysed separately, significant differences for remaining debris were present between groups. The apical third had the most remaining material, whilst the cervical and middle thirds were significantly cleaner (P = 0.002). Comparison of the techniques revealed that teeth instrumented with K3 rotary instruments had a lower ratio of remaining filling material in the apical third (P = 0.012). Conclusion, In the apical third, K3 rotary instruments were more efficient in removing gutta-percha filling material than the other techniques, which were equally effective for the other thirds. [source] Assessment of a contrast medium as an adjunct to endodontic radiographyINTERNATIONAL ENDODONTIC JOURNAL, Issue 12 2004J. M. Bedford Abstract Aim, To assess if a contrast medium improved diagnostic yield of endodontic radiographs. Methodology, Forty-five extracted mandibular premolar teeth were radiographed in bucco-lingual and mesio-distal planes. Access cavities were prepared, pulpal tissue extirpated and Ultravist® contrast medium introduced under pressure. Radiographs were retaken and the teeth cleared following perfusion with India ink. Three examiners assessed all the films for: number of roots, number of root canals, curvature of root and/or root canal, presence of lateral canals, presence of a single foramen or apical delta and the presence or absence of canal obstructions. The examiners' interpretations were compared with the anatomy revealed by clearing. Results, Kappa scores were calculated for each of the examiners, for each set of radiographs, to assess the level of intra- and inter-examiner agreement. Only moderate agreement was found throughout (, = 0.40,0.61). For multiple root canals a false-positive result was significantly more likely with contrast (P < 0.05). The use of contrast did not significantly improve the sensitivity of diagnosis of lateral canals or a single apical foramen. Contrast significantly increased the risk of falsely perceiving lateral canals (P < 0.002). Overall there was no statistically significant difference in the overall assessment of the anatomy of the root canals using contrast or plain radiographs (P > 0.2). Conclusions, Plain film radiographs confidently predict the presence of root or canal curvature but apical anatomy was assessed accurately in only 46% of cases. Plain radiographs were insensitive in assessing the number of root canals present, the presence of lateral canals and the occurrence of canal obstructions. The use of Ultravist® contrast medium to improve diagnosis of root canal morphology of premolars is not supported. [source] Periodontal repair in dogs: space-providing ePTFE devices increase rhBMP-2/ACS-induced bone formationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2003Ulf M.E. Wikesjö Abstract Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) technologies have been shown to enhance alveolar bone formation significantly. Biomaterial (carrier) limitations, however, have restricted their biologic potential for indications where compressive forces may limit the volume of bone formed. The objective of this proof-of-principle study was to evaluate the potential of a space-providing, macroporous ePTFE device to define rhBMP-2-induced alveolar bone formation using a discriminating onlay defect model. Methods: Routine, critical size, 5,6 mm, supra-alveolar, periodontal defects were created around the third and fourth mandibular premolar teeth in four young adult Hound Labrador mongrel dogs. All jaw quadrants received rhBMP-2 (0.4 mg) in an absorbable collagen sponge (ACS) carrier. Contralateral jaw quadrants in subsequent animals were randomly assigned to receive additionally the dome-shaped, macroporous ePTFE device over the rhBMP-2/ACS implant or no additional treatment. The gingival flaps were advanced to cover the ePTFE device and teeth, and sutured. Animals were scheduled for euthanasia to provide for histologic observations of healing at 8 weeks postsurgery. Results: Healing was uneventful without device exposures. New bone formation averaged (±SD) 4.7±0.2 mm (98%) and 4.5±0.4 mm (94%) of the defect height, respectively, for jaw quadrants receiving rhBMP-2/ACS with the ePTFE device or rhBMP-2/ACS alone (p>0.05). In contrast, the regenerated bone area was significantly enhanced in jaw quadrants receiving rhBMP-2/ACS with the ePTFE device compared to rhBMP-2/ACS alone (9.3±2.7 versus 5.1±1.1 mm2; p<0.05). Cementum formation was similar for both treatment groups. Ankylosis compromised periodontal regeneration in all sites. Conclusions: The results suggest that the novel space-providing, macroporous ePTFE device appears suitable as a template to define rhBMP-2/ACS-induced alveolar bone formation. Zusammenfassung Hintergrund: Es wurde gezeigt, dass das rekombinante menschliche knochenmorphogenetische Protein 2 (rhBMP-2) die alveoläre Knochenbildung signifikant erhöht. Limitationen des Biomaterials (Träger) haben jedoch die biologischen Potenzen des Materials für die Indikationen, wo komprimierende Kräfte das Volumen des zu bildenden Knochen limitierten, eingeengt. Das Ziel dieser prinzipiellen geprüften Studie war die Evaluation der Platzhalterfunktion einer makroporösen e-PTFE Membran, um die von rhBMP-2 induzierten Knochenbildung unter Nutzung eines differenzierenden Onlaydefektmodells zu definieren. Methoden: Routinemäßig wurden supraalveoläre parodontale Defekte mit der kritischen Größe von 5,6 mm um die dritten und vierten Prämolaren bei 4 jungen adulten Labrodormischhunden geschaffen. Alle Quadranten erhielten rhBMP-2 (0.4 mg) in einem resorbierbaren Kollagenschwamm (ACS). Kontralaterale Quadranten bei den aufeinander folgenden Tieren wurden zufällig ausgewählt, um zusätzlich eine domförmige makroporöse e-PTFE Membran über das rhBMP-2/ACS Implantat oder keine zusätzliche Therapie zu erhalten. Die gingivalen Lappen wurden so präpariert, dass sie die e-PTFE Membran und Zähne bedeckten und vernäht. Die Tiere wurden 8 Wochen nach der Operation getötet und für histologische Untersuchungen vorbereitet. Ergebnisse: Die Heilung war komplikationslos ohne Exposition der Membran. Die neue Knochenbildung betrug durchschnittlich (±SD) 4.7±0.2 mm (98%) und 4.5±0.4 mm (94%) der Defekthöhe für die Quadranten, die rhBMP-2/ACS mit der e-PTFE Membran erhielten oder rhBMP-2/ACS allein (p>0,05). Im Kontrast dazu war das regenerierte Knochenfeld signifikant erweitert bei den Kieferquadranten, die rhBMP-2/ACS mit e-PTFE Membran erhielten im Vergleich zu denjenigen mit rhBMP-2/ACS allein (9.3±2.7 vs. 5.1±1.1 mm2; p<0.05). Die Zementbildung war in beiden Behandlungsgruppen ähnlich. Ankylosen gefährdeten die parodontalen Regeneration in allen Flächen. Schlussfolgerungen: Die Ergebnisse zeigen, dass die neue makroporöse Platzhalter e-PTFE Membran als Schablone nützlich ist, um die rhBMP-2/ACS induzierte alveoläre Knochenbildung zu betonen. Résumé Contexte: Des technologies utilisant la protéine-2 osseuse morphogénétique humaine recombinée (rhBMP-2) ont montré qu'elle permettait d'augmenter significativement la formation d'os alvéolaire. Les limites du biomatériel (vecteur), cependant, ont restreint leur potentiel biologique aux indications pour lesquels des forces compressives pourraient limiter le volume d'os en formation. L'objectif de cette étude fut d'évaluer le potentiel d'un dispositif en ePTFE macro-poreux permettant de créer un espace pour définir la formation d'os alvéolaire induit par la rhBMP-2 en utilisant un modèle discriminatoire de lésion. Méthodes: Des lésions parodontales supra-alvéolaires de taille critique, 5,6 mm, furent créées autour des troisièmes et quatrièmes prémolaires chez 4 Labrador adultes. Chaque quadrant a été traité par des éponges de collagène résorbables utilisé comme vecteur (ASC) contenant rhBMP-2 (0.4 mg). Les quadrants contralatéraux des animaux furent aléatoirement distribués pour recevoir (ou pas) en plus un dispositif macro-poreux en ePTFE, en forme de dôme sur les implants de rhBMP-2/ACS. Les lambeaux furent déplacés pour recouvrir le dispositif en ePTFE et les dents et suturés. Les animaux furent sacrifiés après 8 semaines pour fournir des observations histologiques de la cicatrisation. Résultats: La cicatrisation ne posait pas de problèmes et on ne nota pas d'exposition des dispositifs. La moyenne de la formation osseuse était de (±SD) 4.7±0.2 mm (98%) et 4.5±0.4 mm (94%) de la hauteur de la lésion, respectivement, pour les quadrants ayant été traités par la rhBMP-2/ACS avec le dispositif en ePTFE ou la rhBMP-2/ACS seule (p>0.05). A l'inverse, la surface osseuse régénérée était significativement plus importante dans les quadrants traités par la rhBMP-2/ACS et les dispositifs en ePTFE par rapport au site traités seulement par la rhBMP-2/ACS (9.3±2.7 vs. 5.1±1.1 mm2; p<0.05). La formation cémentaire était similaire pour les deux groupes de traitement. L'ankylose compromettait la régénération parodontale dans tous les sites. Conclusions: Ces résultats suggèrent que le dispositif en ePTFE macro-poreux, qui assure un espace, semble convenir comme standard pour définir la formation osseuse induite par la rhBMP-2/ACS. [source] | ||||||||||