Ming-Pang Chung

Continued root formation after replantation and root canal treatment in an avulsed immature permanent tooth: a case report

This case report describes the continued root formation following replantation and conventional root canal therapy of a traumatically avulsed open-apex tooth with suppurative apical periodontitis. A 7-year-old male patient had an avulsed upper left central incisor (tooth 21) replanted approximately 50 min after traumatic avulsion. A root canal procedure was initiated due to pulp necrosis and periapical abscess detected in the follow-up period. After endodontic treatment with calcium hydroxide (Ca(OH)(2)) dressing, a normal root length developed including an apical segment beyond the hard tissue barrier. Regeneration of the root occurred without pathology or ankylosis at 1-year of follow up.

Management of crown-root fracture tooth by intra-alveolar transplantation with 180-degree rotation and suture fixation

Teeth with traumatic crown-root fractures extending subgingivally and involving the entire width of the tooth may have problems in endodontic isolation, periodontal maintenance, and restoration. A number of techniques, such as crown lengthening, and orthodontic or surgical extrusion, have been described for treatment of crown-root fractures. However, all of these techniques have limitations in terms of the extended time required for treatment, cost, and esthetic considerations. Intra-alveolar transplantation is an alternative treatment option in the management of complicated crown-root fractures. We describe a case of intra-alveolar transplantation with 180( degrees ) rotation and suture fixation. At 1-year follow-up, the replanted tooth has normal function and no obvious inflammatory root resorption on radiographic examination.

Sodium Hypochlorite Accidentally Extruded Beyond the Apical Foramen

Sodium hypochlorite (NaOCl) is routinely used as an endodontic irrigant to clean and disinfect the root canal system. Although it is generally believed safety, the tissue toxicity of NaOCl cannot be ignored. This report describes two cases of accidental extrusion of sodium hypochlorite solution into the periradicular tissues during root canal instrumentation. The literatures were reviewed to explore possible etiologies and possible complications. Diagnostic criteria for sodium hypochlorite accidents and strategies to mitigate the risk are also suggested.

Complicated Root Canal Configuration of Mandibular First Premolars Is Correlated with the Presence of the Distolingual Root in Mandibular First Molars: A Cone-beam Computed Tomographic Study in Taiwanese Individuals

Introduction: The purpose of this study was to examine the frequency and bilateral consistency of distolingual roots (DLRs) in permanent mandibular first molars (PMFMs) and root canal configurations in PMFPs (permanent mandibular first premolars) and to determine the correlation between the root canal configurations of PMFPs with the appearance of DLRs in PMFMs. Methods: A total of 932 cone‐beam computed tomographic images of PMFMs and PMFPs were collected from 233 patients. The frequency and bilateral consistency of DLRs in PMFMs along with root canal configurations (root number and canal number) of PMFPs were recorded and evaluated ipsilaterally and contralaterally. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMFPs with the appearance of DLRs in PMFMs. Results: The prevalence of PMFMs with DLRs was 24.7%, and the incidence of complicated root canal configurations of PMFPs was 26.6%. The incidence of complicated root canal configurations of PMFPs was 19.6% in the non‐DLR group, 37.2% in the unilateral DLR group, and 44.7% in the bilateral DLR group. After adjusting for categoric variables including sex, age, and side, the odds ratios for the frequency of complicated root canal configurations of PMFPs in the unilateral DLR and bilateral DLR groups compared with the non‐DLR group were 2.472 (95% confidence interval, 1.434–4.263; P = .001) and 3.392 (95% confidence interval, 1.976–5.823; P < .001), respectively. Conclusions: An increasing and corresponding trend between the presence of DLRs in PMFMs and complicated root canal configurations in PMFPs was noted in Taiwanese individuals. These results suggest that the clinicians should familiarize themselves with the anatomic variants of PMFMs and PMFPs before endodontic treatment.

Complicated Root Canal Morphology of Mandibular Lateral Incisors Is Associated with the Presence of Distolingual Root in Mandibular First Molars: A Cone-beam Computed Tomographic Study in a Taiwanese Population

Introduction: The aim of this study was to assess the root canal configurations in permanent mandibular lateral incisors (PMLIs) and the correlation between the root canal configurations of PMLIs with the appearance of a distolingual root (DLR) in permanent mandibular first molars (PMFMs) using cone‐beam computed tomographic (CBCT) imaging. Methods: A total of 1200 CBCT images (300 patients) of PMFMs and PMLIs were investigated. The frequency and distribution of DLRs in PMFMs along with root canal configurations of PMLIs were assessed ipsilaterally and contralaterally. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMLIs with the appearance of a DLR in PMFMs. Results: The prevalence of PMFMs with a DLR was 24.3%, and the incidence of complicated root canal configurations in PMLIs was 25.0%. The most prevalent root canal systems of PMLIs were Vertucci types I (75%) and III (23.0%). The incidence of complicated root canal configurations in PMLIs was 19.5% in the non‐DLR group (ie, no DLR was found on either side of the PMFMs), 33.3% in the unilateral DLR (Uni‐DLR) group (ie, a DLR was found in 1 of the PMFMs [the left or right side] and a DLR was not found on the other PMFM), and 39.8% in the bilateral DLR (Bil‐DLR) group (ie, a DLR was found in both the right and left PMFMs). After adjusting for categoric variables including sex, age, and side, the odds ratios for the frequency of complicated root canal configurations of PMLIs in the Uni‐DLR and Bil‐DLR groups compared with the non‐DLR group were 2.12 (P = .003) and 2.707 (P < .001), respectively. Conclusions: The simultaneous appearance of DLRs in PMFMs and complicated root canal configurations in PMLIs is prominent in Taiwanese individuals. Clinicians should be aware of the correlation between the anatomic variants of PMFMs and PMLIs, which are important before endodontic treatment.

Floating retained root lesion mimicking apical periodontitis

A case of a retained root tip simulating apical periodontitis on radiographic examination is described. The retained root tip, originating from the left lower first molar, floated under the left lower second premolar apical region mimicking apical periodontitis. It appeared as an ill-defined periapical radiolucency containing a smaller radiodense mass on radiograph. The differential diagnosis included focal sclerosing osteomyelitis (condensing osteitis) and ossifying fibroma. Upon exicisional biopsy, a retained root associated with granulation tissue was found. After 1-year follow-up, the patient was asymptomatic and the periradicular lesion was healing. Meanwhile, the associated tooth showed a normal response to stimulation testing.

The Presence of Distolingual Root in Mandibular First Molars Is Correlated with Complicated Root Canal Morphology of Mandibular Central Incisors: A Cone-beam Computed Tomographic Study in a Taiwanese Population

Introduction: The aim of this study was to assess the prevalence of complicated root canals in permanent mandibular central incisors (PMCIs) and its correlation with the presence of a distolingual root (DLR) in permanent mandibular first molars (PMFMs) using cone‐beam computed tomographic imaging in a Taiwanese population. Methods: A total of 400 patients (800 pairs of PMCIs and PMFMs) were qualified for further analysis. The prevalence of DLRs in PMFMs along with root canal configurations of PMCIs were assessed at subject and tooth levels. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMCIs with the existence of DLRs in PMFMs. Results: The prevalence of PMFMs with DLRs and complicated root canal configurations in PMCIs was 23.0% and 15.6%, respectively. A significant difference in age (<50 years vs ≥50 years) was found for complicated root canal configurations in PMCIs. The most prevalent root canal system in PMCIs was Vertucci type I (84.4%) followed by type III (13.5%). A positive correlation between the presence of DLRs in PMFMs and complicated root canal configurations in PMCIs was noted. After adjusting for categoric variables including sex, age, and side, the odds ratios for the occurrence of complicated root canal configurations of PMCIs in the unilateral DLR group and the bilateral DLR group compared with the non‐DLR group were 2.13 and 2.53, respectively. Conclusions: The concurrent appearance of DLRs in PMFMs and complicated root canal morphology in PMCIs is prominent in Taiwanese individuals.

Relationship of the Incidence of C-shaped Root Canal Configurations of Mandibular First Premolars with Distolingual Roots in Mandibular First Molars in a Taiwanese Population: A Cone-beam Computed Tomographic Study

Introduction The aim of this study was to determine the prevalence of C‐shaped canal configurations (CSs) and radicular grooves (RGs) in permanent mandibular first premolars (MPs) and to investigate the relevance of such complexities with the presence of distolingual roots (DLRs) in permanent mandibular first molars (MMs). Methods A total of 800 pairs of MPs and MMs were investigated using a cone‐beam computed tomographic system (NewTom 5G; QR srl, Verona, Italy). The frequency and symmetry of DLRs in MMs along with the occurrence of RGs and CSs in examined MPs were evaluated. Multivariable logistic regression analysis was applied to examine the correlation between the CSs of MPs with the appearance of DLRs in MMs. Results In the examined teeth, 23.0% of MMs had a DLR, whereas 16.6% of MPs had RGs and 12.5% of MPs had C‐shaped canals. Although the most common canal configuration in MPs is the single canal (74.1%), the other 25.9% still possess complicated root canals. Of these MPs that have different canal configurations, 54.6% had 2 canals, whereas 44.4% had CSs. Specifically, the CS showed a high prevalence of C3 morphologies at 98.9% followed by C1 at 1.1%. A corresponding and increasing frequency was noted in CSs and RGs of MPs and MMs with DLRs (P < .001). After adjusting for related categoric variables, the adjusted odds ratios for CSs of MPs in the bilateral DLR group compared with the non‐DLR group was 3.294 (P < .001). Conclusions This study showed an increased appearance of CSs in MPs when DLRs were present in MMs in the Taiwanese population.

The prevalence and distribution of radiopaque, calcified pulp stones: A cone-beam computed tomography study in a northern Taiwanese population

Background/purpose Presence of pulp stones increase the difficulty of locating canal orifice during endodontic treatment. This study aims to determine the prevalence of pulp stones in a northern Taiwanese population through analysis of cone beam computed tomography (CBCT). Materials and methods A total of 144 patients and 2554 teeth were used in the present study which were collected from a CBCT image archive. To determine the presence of pulp stones, images of pulp chamber and root canals were analyzed in the sagittal, axial and coronal planes and from the occlusal to apical direction. Correlations between pulp stones and gender, age, tooth type, dental arch or side were also examined. Results Of the 144 patients, 120 patients (83.3%) and 800 (31.3%) teeth were found to have one or more pulp stones through CBCT examination. Prevalence of pulp stones between dental arches and tooth types were significantly different (P < 0.001). Pulp stones were found to be the most prevalent in first molars (50.0%) and most scarce in first premolars (18.8%). There was no significant correlation between pulp stones and gender, increasing age, or dental sides. Conclusion Pulp stones are more frequent in maxillary teeth compared to mandibular teeth. Pulp stones in molar teeth were significantly more common than premolars and incisors. CBCT could be a sensitive tool to detect pulp stones, especially simplifying identification of pulp stones in radicular pulp. Knowledge of pulp stones distribution can aid dentists in clinical endodontic treatment.

Geometric features of second mesiobuccal canal in permanent maxillary first molars: a cone-beam computed tomography study

Background/purpose Inadequacy to locate the second mesiobuccal canal (MB2) canal leads to the highest probability of endodontic failure in permanent maxillary first molars (PMFMs) and still remains a constant challenge for many clinicians. The aim of this study was to characterize the geometrical features between MB2 and other orifices of examined PMFMs using cone-beam computed tomography images. Materials and methods A total of 108 teeth qualified in the cone-beam computed tomography image archives were enrolled in the present study. The intersecting point (T) was determined as the perpendicular line (h, altitude of triangle) projected from the vertex of the MB2 canal orifice to mesiobuccal canal orifice-palatal canal orifice line (MB1-P). We measured the geometric features of PMFMs with the MB2 canal, including the interorifice distances, area, altitude, and the ratio between the canal orifices. Results The average interorifice distance was found to be 1.91 ± 0.59 mm for MB1-MB2, 5.73 ± 0.66 mm for MB1-P, and 4.11 ± 0.79 mm for MB2-P, with significant gender difference for MB1-MB2 distance. For the MB1-T distance, a significant difference was found between genders (P = 0.02), with males averaging 1.78 ± 0.07 mm, and females 1.48 ± 0.11 mm. For the MB1-P distance, the majorities of both genders were found in the 20–40% cut-off. A portion of the males exhibited a tendency towards the 40–80% cut-off, while females shifted in the reverse direction towards the 0–20% cut-off. Conclusion In clinical scenarios, these anatomical characteristics of the root canals system could be beneficial to locating the MB2 canal.