Shue-Fen Yang

Nonsurgical Endodontic Treatment of Dens Invaginatus with Large Periradicular Lesion: A Case Report

The endodontic treatment of teeth with severe Type 3 dens invaginatus, characterized by an infolding of enamel and dentin, extending deep into the pulp cavity near the root apex, may be complicated and challenging. Because of the bizarre root canal anatomy and widely open apex, a combination of nonsurgical and surgical endodontic treatment or extraction is the most common choice of therapy. This article describes a nonsurgical endodontic treatment of a tooth with severe Type 3 dens invaginatus and an associated large periradicular lesion. After complete removal of the invaginated central mass of hard tissue and long-term calcium hydroxide treatment, nonsurgical endodontic treatment was performed. Complete healing of the periradicular lesion was observed at 25-month and 74-month follow-up examinations.

The Morphologic Characteristics of the Distolingual Roots of Mandibular First Molars in a Taiwanese Population

INTRODUCTION The prevalence of extra distolingual (DL) roots in mandibular first molars in Chinese population is about 20%. The purpose of this study was to evaluate the difference of root length and root curvatures between distobuccal (DB) and DL roots of three-rooted mandibular first molars in a Taiwanese (Chinese) population. METHODS Of the 293 extracted mandibular first molars, DL roots were present in 29 (9.9%) teeth. Excluding teeth with fractured DB or DL roots, 21 mandibular first molars were further investigated. DB and DL root lengths were measured from the lower level of furcation at the distal surface to the root apex. The curvature of the DL root was measured on mesial-distal and buccal-lingual radiographs by Schneiders technique. RESULTS The DL roots were significantly (p < 0.001) shorter than the DB roots with an average of 1.48 +/- 0.81 mm. Most DL roots had a greater curvature in a buccal-lingual orientation (36.35 degrees +/- 9.38 degrees ) than a mesial-distal orientation (9.24 degrees +/- 6.10 degrees ) and 28.57% of the curved DL roots had the curvature at the apical one third (p < 0.001). CONCLUSION The results of this study verified the characteristics of shorter root length and severe buccal-lingual inclination of DL roots in three-rooted mandibular first molars.

Up-regulation of nucleotide-binding oligomerization domain 1 in inflamed human dental pulp.

INTRODUCTION The innate immune response is activated by recognition of microbial components through specific pattern recognition receptors including nucleotide-binding oligomerization domain (NOD)-like receptors. However, the regulation of NOD-1 in inflamed human dental pulp remains poorly understood. This study aimed to evaluate the expression of NOD-1 in healthy and inflamed human dental pulps. In addition, the secretion of chemokines induced by NOD-1 and the related signaling pathways were studied. METHODS Samples of human dental pulp tissues were obtained from freshly extracted wisdom teeth. The protein localization of NOD-1 in the pulp tissues was detected by immunohistochemistry. In addition, human dental pulp fibroblasts were stimulated with NOD-1 agonist γ-D-glutamylmeso-diaminopimelic acid. Production of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) was determined by an enzyme-linked immunosorbent assay. The involvement of mitogen-activated protein kinase (MAPK) signaling pathways was examined by Western blot analysis, and the association of MAPK signaling with chemokine production was determined. RESULTS The results demonstrated the expression of NOD-1 in normal dental pulp, and up-regulated NOD-1 expression was observed in inflamed dental pulp. On stimulation with NOD-1 agonist, production of IL-8 and MCP-1 was induced in a dose-dependent manner. Moreover, phosphorylation of p38 MAPK and Jun N-terminal kinase (JNK) was enhanced by stimulation of NOD-1. With the treatment of p38 MAPK and JNK inhibitors, the NOD-1-induced IL-8 production was suppressed. CONCLUSIONS In response to microbial invasion, the expression of NOD-1 can be regulated in a ligand-inducible manner. NOD-1 might participate in pulp inflammation through chemokine production via MAPK signaling pathways.

Refractory apical periodontitis associated with a calculus-like deposit at the root apex

In this case report, we describe a refractory case in which a calculus-like deposit was found at the apical root surfaces of two adjacent teeth. This case involved a 45-year-old male with a sinus tract at the labial mucosa of the maxillary left central incisor, which did not heal after conventional root canal treatment of the maxillary left lateral incisor. Periradicular radiolucencies and unusual radio-opacities were noted on the root surfaces of the vital maxillary left central incisor and prior endodontically treated lateral incisor. Subsequent surgery found calculus-like particles at the root surface of both teeth. A pathology examination revealed calculus-like particles scattered in the granulomatous tissue. A test cavity confirmed pulp necrosis of the maxillary central incisor, and endodontic treatment was performed 1 year after surgery. At the 20-month recall, the size of the periapical radiolucency had decreased. The presence of calculus-like particles at the root surfaces was noted and may have possibly contributed towards the etiology of root canal treatment failure.

Expression of p21 and p53 in rat gingival and human oral epithelial cells after cyclosporine A treatment

BACKGROUND AND OBJECTIVE Expression of p21 and p53 were examined, at gene and protein levels, in edentulous gingival epithelial cells from rats and from a human oral epidermoid carcinoma cell line, OECM1, after cyclosporine A therapy. MATERIAL AND METHODS In vivo: 20 partially edentulous SD rats were assigned into cyclosporine A feeding and control groups. After the rats were killed, p21 and p53 in gingiva were evaluated by reverse transcription-polymerase chain reaction and immunohistochemistry. In vitro: after cyclosporine A treatment, p21 and p53 of OECM1 cells were evaluated by western blot and the luciferase assay. The distribution of OECM1 cells in each phase of the cell cycle was evaluated by flow cytometry. RESULTS The mRNA expression of p21 was significantly higher in the cyclosporine A group than in the control group. A greater number of positive anti-p21-stained cells were observed in the gingival epithelium of the cyclosporine A group than in the control group. Significantly higher levels of p21 protein and activity were observed in OECM1 cells after cyclosporine A treatment than in cells without treatment. A relative increase of cells in G0/G1 phases, and a decrease of cells in G2/M phases, were observed in OECM1 cells after cyclosporine A treatment. CONCLUSION In the present study, higher p21 mRNA and protein expressions were observed after cyclosporine A treatment. Thus, an up-regulation of p21 expression, via a p53-independent pathway, by cyclosporine A in gingival and oral epithelial cells was suggested.

Maxillary first molar with six canals

In this case report, we present a maxillary first molar with six canals. A 40-year-old male patient was referred for non-surgical root canal therapy of tooth 16. Under magnification of a surgical operating microscope, a unique morphology with double canal systems in each root was identified. The morphology was characterized by a single palatal root with two canals joining in the apical third, two mesiobuccal canals, and two distobuccal canals with one orifice and two separate foramina.

The best radiographic method for determining root canal morphology in mandibular first premolars: A study of Chinese descendants in Taiwan

Background/purpose There is large variation in root canal morphology and undetected canals and incomplete instrumentation are reasons for root canal treatment failure. The purpose of this study was to determine the best radiographic method for determining root canal morphology in mandibular first premolars in Chinese descendants in Taiwan. Materials and methods Mandibular first premolars extracted due to caries, periodontal diseases, trauma, or for orthodontic reasons were used. Four indices were examined: (1) root canal bifurcation observed in the buccolingual view; (2) root canal continuity in the buccolingual view; (3) double root outline in the buccolingual view; and (4) Vertucci canal classification in the mesiodistal view. Results A total of 82 left and right mandibular first premolars were included, a complicated root canal was confirmed in 38 (46.3%) by cross-sectional imaging and a single root canal was found in 44 (53.7%). Bifurcation identified on the mesiodistal view exhibited the highest sensitivity (94.7%) and second highest specificity (88.6%) for identifying a complicated root canal; however, this view is not possible to obtain clinically. Canal bifurcation on the buccolingual view was the most specific (93.2%), but had the lowest sensitivity (73.7%). Canal continuity on the buccolingual view had a sensitivity of 94.7%, and specificity of 70.5%. Conclusion Combined X-ray analyses, such as performing the buccolingual view for identification of canal bifurcation and canal continuity, may increase the accuracy of identifying complex root canal morphology.