Abstract: Plants have evolved some mechanisms to maximize the efficiency of phosphorus acquisition. Changes in root architecture are one such mechanism. When Fraxinus mandshurica Rupr. seedlings were grown under condi...Abstract: Plants have evolved some mechanisms to maximize the efficiency of phosphorus acquisition. Changes in root architecture are one such mechanism. When Fraxinus mandshurica Rupr. seedlings were grown under conditions of low phosphorus availability, the length of cells in the meristem zone of the lateral roots was longer, but the length of cells in the elongation and mature zones of the lateral roots was shorter, compared with seedlings grown under conditions of high phosphorus availability. The elongation rates of primary roots increased as phosphorus availability increased, but the elongation rates of the branched zones of the primary roots decreased. The number of lateral root primordia and the length of the lateral roots decreased as phosphorus availability increased. The topological index (altitude slope) decreased as phosphorus availability increased, suggesting that root architecture tended to be herringbone-like when seedlings were grown under conditions of low phosphate availability. Herringbone-like root systems exploit nutrients more efficiently, but they have higher construction costs than root systems with a branching pattern.展开更多
Aim: In this in vitro study the variation of root anatomy and canal system of the first human maxillary premolar was evaluated. Materials and Methods: Two hundred and twenty one maxillary first premolars (#221 teeth) ...Aim: In this in vitro study the variation of root anatomy and canal system of the first human maxillary premolar was evaluated. Materials and Methods: Two hundred and twenty one maxillary first premolars (#221 teeth) were examined. All of the teeth were identified using the accepted criteria of Woelfel as maxillary first premolars. Selected teeth are analyzed using operating microscope (OP) and computed dental radiography (CDR). Results: There was a higher incidence of two-roots form 70.14% (n = 155), 21.72% (n = 48) had one root, and 8.14% (n = 18) had three roots. In the two-root category, 16.29% (n = 36) had bifurcation on apical third, 21.72% (n = 48) had bifurcation on middle third, and 32.13% (n = 71) had bifurcation on cervical third. The examination of root canal systems of the teeth was based on Vertucci’s classification type of canal: 64.58% (#31) of the cases had type IV (2-2-2), 25.00% (#12) type II (2-2-1), 8.33% (#4) type I (1-1-1), and 2.09% (#1) type III (1-2-1). Conclusion: This study showed a high incidence of two-rooted maxillary first premolars collected from different regions in Kosovo. Internal root canal system morphology reflects the external root anatomy. Furthermore, there is correlation between the shape of the outer surface of the root and the shape of the root canal. The cases with one root of the maxillary first premolar with a deep depression on the mesial side contain a double root canal system more often than a single canal.展开更多
The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases (amounting to a to...The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases (amounting to a total of 1 005 root canals) were examined. The anatomy risk factors assessed in each case included: tooth type (tooth location), root canal curvature, and root canal calcification, as well as endodontic retreatment. The investigation examined the correlation between each of these anatomic factors and the working length, with statistical analysis consisting of Chi-square tests and multiple logistic regression analysis. In an independent factor analysis, tooth type (tooth iocation), root canal curvature, canal calcification, and endodontic retreatment were determined to be the primary risk factors. In a multiple-factor regression model, root curvature and canal calcification were found to most significantly influence root canal working length accessibility (P〈0.05). Root canal anatomy increases the difficulty of root canal preparation. Appropriate consideration of tooth anatomy will assist in accurate determination of preparation difficulty before instrumentation. This study alerts clinical therapists to anatomical factors influencing the working length accessibility, and allows for a direct estimate of success rate given in situ measurements of tooth factors during the root canal treatment procedure.展开更多
Aim: To confirm the effect of root canal treatment on radix entomolaris. Case: Radix entomolaris was an additional root that located on the distolingual of mandibular first molars. In this case, the radix entomolaris ...Aim: To confirm the effect of root canal treatment on radix entomolaris. Case: Radix entomolaris was an additional root that located on the distolingual of mandibular first molars. In this case, the radix entomolaris was detected clinically and radiographically with root canal configuration such as curves. An awareness and understanding of this unusual root and root canal morphology could contribute to the successful outcome of endodontic treatment. Conclusion: Root canal treatment on this case shows the lack of symptoms and normal radiographic presentation for two months follow-up.展开更多
This case report is to present a maxillary first molar with one O-shaped root, which is an extended C-shaped canal system. Patient with chronic apical periodontitis in maxillary left first molar underwent replantation...This case report is to present a maxillary first molar with one O-shaped root, which is an extended C-shaped canal system. Patient with chronic apical periodontitis in maxillary left first molar underwent replantation because of difficulty in negotiating all canals. Periapical radiographs and cone-beam computed tomography (CBCT) were taken. All roots were connected and fused to one root, and all canals seemed to be connected to form an O-shape. The apical 3 mm of the root were resected and retrograde filled with resin-modified glass ionomer. Intentional replantation as an alternative treatment could be considered in a maxillary first molar having an unusual O-shaped root.展开更多
BACKGROUND As the complex anatomy of maxillary first molars is one of the major challenges in endodontic therapy,knowledge of the complicated root canal anatomy and configuration is crucial to ensure the success of en...BACKGROUND As the complex anatomy of maxillary first molars is one of the major challenges in endodontic therapy,knowledge of the complicated root canal anatomy and configuration is crucial to ensure the success of endodontic treatment and prognosis.This article presents an endodontically managed left maxillary first molar with an unusual palatal root morphology.The available literature on the anatomic variation of maxillary first molars is also reviewed.CASE SUMMARY A 36-year-old man with no medical history presented to the Stomatology Department of Peking University Third Hospital complaining of a toothache during mastication in the maxillary left posterior region for approximately 3 mo.He had a spontaneous and intermittent toothache that had worsened,particularly at night.The diagnosis based on clinical examination,X-ray imaging,and cone beam computed tomography(CBCT)was symptomatic irreversible pulpitis.Nonsurgical endodontic therapy was performed for the left maxillary first molar.Five root canals revealed by CBCT included a special palatal root canal(1-2-1-shaped),two mesiobuccal root canals,and one distobuccal root canal.Evaluation of the CBCT images confirmed the root canal morphology and the clinician performed more effective cleaning,obturation,and therapy.Finally,the tooth was restored using composite resin,and the patient was satisfied with the result.CONCLUSION CBCT and a complete review of the literature may be beneficial for investigating the root canal system to achieve a biological and functional therapeutic effect.展开更多
文摘Abstract: Plants have evolved some mechanisms to maximize the efficiency of phosphorus acquisition. Changes in root architecture are one such mechanism. When Fraxinus mandshurica Rupr. seedlings were grown under conditions of low phosphorus availability, the length of cells in the meristem zone of the lateral roots was longer, but the length of cells in the elongation and mature zones of the lateral roots was shorter, compared with seedlings grown under conditions of high phosphorus availability. The elongation rates of primary roots increased as phosphorus availability increased, but the elongation rates of the branched zones of the primary roots decreased. The number of lateral root primordia and the length of the lateral roots decreased as phosphorus availability increased. The topological index (altitude slope) decreased as phosphorus availability increased, suggesting that root architecture tended to be herringbone-like when seedlings were grown under conditions of low phosphate availability. Herringbone-like root systems exploit nutrients more efficiently, but they have higher construction costs than root systems with a branching pattern.
文摘Aim: In this in vitro study the variation of root anatomy and canal system of the first human maxillary premolar was evaluated. Materials and Methods: Two hundred and twenty one maxillary first premolars (#221 teeth) were examined. All of the teeth were identified using the accepted criteria of Woelfel as maxillary first premolars. Selected teeth are analyzed using operating microscope (OP) and computed dental radiography (CDR). Results: There was a higher incidence of two-roots form 70.14% (n = 155), 21.72% (n = 48) had one root, and 8.14% (n = 18) had three roots. In the two-root category, 16.29% (n = 36) had bifurcation on apical third, 21.72% (n = 48) had bifurcation on middle third, and 32.13% (n = 71) had bifurcation on cervical third. The examination of root canal systems of the teeth was based on Vertucci’s classification type of canal: 64.58% (#31) of the cases had type IV (2-2-2), 25.00% (#12) type II (2-2-1), 8.33% (#4) type I (1-1-1), and 2.09% (#1) type III (1-2-1). Conclusion: This study showed a high incidence of two-rooted maxillary first premolars collected from different regions in Kosovo. Internal root canal system morphology reflects the external root anatomy. Furthermore, there is correlation between the shape of the outer surface of the root and the shape of the root canal. The cases with one root of the maxillary first premolar with a deep depression on the mesial side contain a double root canal system more often than a single canal.
基金supported by State Key Laboratory of Oral Diseases and Department of Endodontics and Operative Dentistry, West China School of Stomatology, Sichuan Universitysupported by the Key Clinical Program of the Ministry of Health of China (2010)National Key Clinical Program of China (2010)
文摘The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases (amounting to a total of 1 005 root canals) were examined. The anatomy risk factors assessed in each case included: tooth type (tooth location), root canal curvature, and root canal calcification, as well as endodontic retreatment. The investigation examined the correlation between each of these anatomic factors and the working length, with statistical analysis consisting of Chi-square tests and multiple logistic regression analysis. In an independent factor analysis, tooth type (tooth iocation), root canal curvature, canal calcification, and endodontic retreatment were determined to be the primary risk factors. In a multiple-factor regression model, root curvature and canal calcification were found to most significantly influence root canal working length accessibility (P〈0.05). Root canal anatomy increases the difficulty of root canal preparation. Appropriate consideration of tooth anatomy will assist in accurate determination of preparation difficulty before instrumentation. This study alerts clinical therapists to anatomical factors influencing the working length accessibility, and allows for a direct estimate of success rate given in situ measurements of tooth factors during the root canal treatment procedure.
文摘Aim: To confirm the effect of root canal treatment on radix entomolaris. Case: Radix entomolaris was an additional root that located on the distolingual of mandibular first molars. In this case, the radix entomolaris was detected clinically and radiographically with root canal configuration such as curves. An awareness and understanding of this unusual root and root canal morphology could contribute to the successful outcome of endodontic treatment. Conclusion: Root canal treatment on this case shows the lack of symptoms and normal radiographic presentation for two months follow-up.
文摘This case report is to present a maxillary first molar with one O-shaped root, which is an extended C-shaped canal system. Patient with chronic apical periodontitis in maxillary left first molar underwent replantation because of difficulty in negotiating all canals. Periapical radiographs and cone-beam computed tomography (CBCT) were taken. All roots were connected and fused to one root, and all canals seemed to be connected to form an O-shape. The apical 3 mm of the root were resected and retrograde filled with resin-modified glass ionomer. Intentional replantation as an alternative treatment could be considered in a maxillary first molar having an unusual O-shaped root.
基金Supported by the National Natural Science Foundation of China,No.81800983Beijing Natural Science Foundation,No.7164310.
文摘BACKGROUND As the complex anatomy of maxillary first molars is one of the major challenges in endodontic therapy,knowledge of the complicated root canal anatomy and configuration is crucial to ensure the success of endodontic treatment and prognosis.This article presents an endodontically managed left maxillary first molar with an unusual palatal root morphology.The available literature on the anatomic variation of maxillary first molars is also reviewed.CASE SUMMARY A 36-year-old man with no medical history presented to the Stomatology Department of Peking University Third Hospital complaining of a toothache during mastication in the maxillary left posterior region for approximately 3 mo.He had a spontaneous and intermittent toothache that had worsened,particularly at night.The diagnosis based on clinical examination,X-ray imaging,and cone beam computed tomography(CBCT)was symptomatic irreversible pulpitis.Nonsurgical endodontic therapy was performed for the left maxillary first molar.Five root canals revealed by CBCT included a special palatal root canal(1-2-1-shaped),two mesiobuccal root canals,and one distobuccal root canal.Evaluation of the CBCT images confirmed the root canal morphology and the clinician performed more effective cleaning,obturation,and therapy.Finally,the tooth was restored using composite resin,and the patient was satisfied with the result.CONCLUSION CBCT and a complete review of the literature may be beneficial for investigating the root canal system to achieve a biological and functional therapeutic effect.