It is a basic prerequisite for the successful completion of endodontic treatment to thoroughly understand the root canal space anatomy. With the development of dental devices in dentistry, the root canal morphology of the mandibular first premolars can be presented in more detail. Before conducting root canal therapy on the mandibular first premolar with complex root canal morphology, it should be necessary to evaluate the potential difficulties and risks for making an appropriate treatment plan. The present paper reviews the research progress on the diversities of root canal morphology in mandibular first premolars in recent years, and then makes technologic recommendations based on the morphology diversities.
Humans ; Dental Pulp Cavity/diagnostic imaging* ; Bicuspid/anatomy & histology* ; Mandible ; Tooth Root/anatomy & histology* ; Root Canal Therapy

OBJECTIVEThis research aimed to analyze the three-dimensional position of mandibular canal (MC) and man of MC and its relationship with the surrounding structures dibular morphology of normal young males and females by using data from cone beam computed tomography (CBCT), as well as to provide an anatomical basis for clinical surgery of the mandible.

METHODSNormal occlusion and CBCT scans of 29 normal young people were conducted. InVivo 5 software was used to reconstruct the mandible, anchor the points, and measure the jaw shape and three-dimensional course of MC. All measurements were analyzed with SSPS 17.0 software.

RESULTSThe MC lingual bone cortex was thinner than the MC buccal bone cortex, and the distance of the MC to the buccal bone cortex gradually increased. However, the distance of the MC to the tongue bone cortex and alveolar crest gradually decreased from proximal to distal. In addition, the distance of the MC to the mandibular lower margin was minimal at the first molar and reached the maximum at the second premolar. No significant difference was observed among the heights, widths, and thicknesses of the left and right sides of the cortical bone of the mandibular body cross sections. From the midline to the farthest point, the height and lower one-third thickness of the lingual cortical bone of the mandibular body cross sections gradually decreased, whereas the width of the upper cross section and upper one-third thickness of the buccal cortical bone gradually increased. Significant difference was observed in some measured values.

CONCLUSIONAfter MC enter into the mandibular foramen, it moved away from the lingual to the buccal bone but gradually returned to the lingual bone; its general course is closer to the lingual bone. The mandibles of males are thicker than those of females. CBCT can accurately display the course of MC and its relationship with the surrounding structures.

Alveolar Process ; Bicuspid ; Cone-Beam Computed Tomography ; methods ; Dental Pulp Cavity ; Female ; Humans ; Hyoid Bone ; Male ; Mandible ; anatomy & histology ; diagnostic imaging ; Molar ; Software ; Surveys and Questionnaires ; Tongue ; Zygoma

PURPOSE: This study aimed to investigate the clinical anatomy of lower premolar roots in a Spanish population by using cone-beam computed tomography (CBCT), correlating findings with patient gender and tooth type. MATERIALS AND METHODS: Using 70 CBCT images, we evaluated 126 healthy, untreated, well-developed lower premolars. The number and morphology of roots and root canals, and the foramina number were assessed. Results for gender and tooth type were compared using the chi-squared and ANOVA tests. RESULTS: The average length of teeth and roots was significantly higher in men (p=0.00). All 126 premolars had a single root. One canal was found in 83.3% of the premolars, with no gender or tooth type differences; Vertucci configuration types I and V were the most prevalent. The first premolars showed significantly greater variability than the second premolars (p=0.03). A single apical foramen was found in 89.7% of the premolars, with no differences by tooth type. Women had a significantly higher prevalence of two apical foramina than men (p=0.04). Some degree of curvature was observed in 65% of the premolars, with no differences by gender or tooth type. A root angle of more than 20degrees was found in 12.98% of the premolars, without any differences by gender or tooth. CONCLUSION: All premolars were single-rooted. One canal had the most prevalent morphology. More variability in canal anatomy was found in the first premolars. Curvatures greater than 20degrees were found at less than 5 mm from the apex.
Anatomy, Regional ; Bicuspid* ; Cone-Beam Computed Tomography* ; Dental Pulp Cavity ; Female ; Humans ; Male ; Mandible ; Prevalence ; Tooth ; Tooth Apex

The purpose of this study was to evaluate the effect of age on the ratio of pulp cavity/tooth width (P/T ratio) in healthy cats. The dental radiographs of 32 cats (16 males and 16 females) were generated with a digital dental X-ray unit with the animals under general anesthesia. Standardized measurement of the canine teeth was performed by drawing a line on the radiograph perpendicular to the cementoenamel junction (CEJ) of the tooth. There was an inversely proportional correlation between chronological age and the P/T ratio. Moreover, a strong Pearson squared correlation (gamma2 = 0.92) was identified by the curved regression model. No significant differences in the P/T ratio based on gender or breed were found. These results suggest that determination of age by P/T ratio could be clinically useful for estimating the chronological age of cats.
Age Determination by Teeth/*veterinary ; Animals ; Cats/*physiology ; Dental Pulp Cavity/anatomy & histology/*radiography ; Female ; Male ; Tooth/anatomy & histology/*radiography

The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to compare the relative efficacies of these methods. For the recognition of C-shaped root canal system, 1 146 mandibular second molars were selected and examined. Teeth with C-shaped canal systems were categorized by using the radiographic classification criteria and the modified Melton's method. C-shaped canals were identified in 397 (34.64%) mandibular second molars by radiography (type I, 31.23%; type II, 38.29%; type III, 30.48%). Clinical examination showed that 449 (39.18%) cases exhibited C-shaped canal systems (C1, 22.94%; C2, 48.11%; C3a, 15.59%; C3b, 13.36%). As for the result of the radiographic and clinical combined examination, C-shaped root canals were found in 473 (41.27%) mandibular second molars (C1, 21.78%; C2, 45.67%; C3a, 16.70%; C3b, 15.86%). The incidence of C-shaped root canal diagnosed by radiographic method was statistically different from that by clinical examination and the combined examination (P<0.05). The study indicated a high incidence of C-shaped canal system in a Chinese population. The combination of microscopic and radiographic examination is an effective method in identifying the C-shaped root canal system.
Adult ; Aged ; Anatomic Variation ; Asian Continental Ancestry Group ; Chi-Square Distribution ; China ; Dental Pulp Cavity ; anatomy & histology ; diagnostic imaging ; Female ; Humans ; Male ; Mandible ; Microscopy ; Middle Aged ; Molar ; anatomy & histology ; Radiography, Dental ; Tooth Root ; anatomy & histology ; Young Adult

We present a case of a patient with rare anatomy of a maxillary second molar with three mesiobuccal root canals and a maxillary third molar with four separate roots, identified using multi-slice computed topography (CT) and three-dimensional reconstruction techniques. The described case enriched/might enrich our knowledge about possible anatomical aberrations of maxillary molars. In addition, we demonstrate the role of multi-slice CT as an objective tool for confirmatory diagnosis and successful endodontic management.
Adult ; Asian Continental Ancestry Group ; China ; Dental Pulp Cavity ; anatomy & histology ; diagnostic imaging ; Female ; Humans ; Imaging, Three-Dimensional ; Maxilla ; Molar ; anatomy & histology ; diagnostic imaging ; Molar, Third ; anatomy & histology ; diagnostic imaging ; Root Canal Therapy ; Tomography, X-Ray Computed ; methods ; Tooth Root ; anatomy & histology ; diagnostic imaging

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 location), 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.
Chi-Square Distribution ; Dental Pulp Calcification ; pathology ; Dental Pulp Cavity ; anatomy & histology ; diagnostic imaging ; Humans ; Logistic Models ; Odontometry ; Radiography ; Retreatment ; Risk Factors ; Root Canal Preparation ; instrumentation ; Tooth Apex ; Tooth Root ; anatomy & histology

Dental Pulp Cavity ; anatomy & histology ; Humans ; Male ; Maxilla ; Middle Aged ; Molar ; anatomy & histology ; Odontometry ; Tooth Root ; anatomy & histology

Dental Pulp Cavity ; anatomy & histology ; diagnostic imaging ; Humans ; Radiography ; Root Canal Therapy ; methods

OBJECTIVETo investigate the incidence of the second mesiobuccal canal (MB2) in the mesiobuccal root of the maxillary first and second molars in Chinese population using three techniques, including the clearing technique, spiral CT scanning and serial root sections.

METHODSA total of 216 extracted human first and 334 second maxillary molars were randomly divided into two groups respectively: group A and B. The teeth in group A were cleared. The specimens in group B were subjected to spiral CT scanning, and then the roots were cross-sectioned every 1 mm from the root apex. Under the Dental operating microscope (DOM), the incidence of MB2 were recorded.

RESULTS(1) The incidence of MB2 in the first and the second maxillary molars were 81.48% and 49.70% respectively by clearing, and 77.78% and 47.31% from S-CT scanning, 88.89% and 53.89% respectively from serial root section. The occurrence of MB2 in maxillary first molars was statistically higher than in maxillary second molars (P < 0.05, chi square test). (2) There was no significant difference among the three approaches for detecting the MB2 canal (P > 0.05, chi square test).

CONCLUSIONSBoth the maxillary first molars and the second molars have high incidence of MB2.

Dental Pulp Cavity ; anatomy & histology ; diagnostic imaging ; Humans ; In Vitro Techniques ; Molar ; anatomy & histology ; diagnostic imaging ; Radiography