Distal root curvatures in mandibular molars: analysis using digital panoramic X-rays

Investigation of the Radiological Status of Permanent First Molars in a Turkish Subpopulation

Objective: Missing or filled first permanent molars (FPMs) affects occlusal status and oral health. This study aims to determine the prevalence of missing, restored FPMs (filling, root canal treatment, prosthetic restoration), and dental implants in the first molar region. Methods: In our study, panoramic radiographs of 1765 female and 1230 male patients were evaluated. Patients were divided into three age groups: 15-34 years old, 35-54 years old, and >55 years old. The maxillary and mandibular FPMs status is divided into two groups presence (caries, filled, root treatment, prosthetic restoration, root treatment + prosthetic restoration, and healthy) or absence (empty, radix relicta, dental implant, and dental bridge). Results: In the evaluated images, 36.92% of maxillary FPMs and 27.39% of mandibular FPMs were healthy. FPMs on the right or left side of the jaws did not affect their clinical status, while their presence on the lower or upper jaw affected their clinical status. Conclusion: Most of the FPMs (67.85%) were with caries or restorations. The number of healthy FPMs decreases with increasing age. The study indicates an important result regarding protecting FPMs and preventive dentistry.

Dental anomalies in non-syndromic orofacial clefts: a clinical approach

Orofacial clefts (OC) represent some of the most common congenital malformations and affect multiple structures in the craniofacial region. There are a wide range of morphological OC types within the spectrum of both non-syndromic OC (NSOC) and syndromic OC, including cleft lip (CL); cleft lip and palate (CLP) and cleft palate (CP). Here, we describe the most frequent dental anomalies seen in the permanent dentition of individuals with NSOC, comparing them between the three main cleft types (CL, CLP, CP). We present these findings from the perspective of prevalence relating to each anomaly, as well as the clinical characteristics and potential impact in the rehabilitation process. The investigation of dental anomalies associated with NSOC is important, helping to expand the phenotypic characterization of NSOC, improve initial diagnostics and establish appropriate rehabilitation and counseling.

A novel approach to radiographic detection of bucco-palatal/lingual dilacerations: A preliminary study with ImageJ

The purpose of our study is to determine whether bucco-palatal/lingual (BPL) root dilacerations (RD), especially in single root teeth, can be determined using the ImageJ program through only one periapical radiography. Extracted teeth without any RD (n = 8) were determined as the control group (Group 1) and with RD in apical 1/3 part at least 20° with the longitudinal axis in the BPL direction (n = 8) as the study group (Group 2). With the help of a simple holder system prepared, digital periapical radiographs of all teeth were taken in an anteroposterior position. Histogram analysis of all periapical radiographs was performed using the spectrum feature of ImageJ software. It was aimed to make a dilaceration analysis by comparing the groups using mean, standard deviation, minimum, maximum, and bin width values. As a result of the Mann-Whitney U test, all mean and maximum values showed a statistically significant difference between the study and control groups (p < 0.05). This pilot study revealed that the ImageJ software can be used to diagnose BPL dilaceration in the apical 1/3 part of the root. It is important for dentists and patients that it can contribute to limiting the radiation dose to which patients will be exposed.

Classification and morphology of middle mesial canals of mandibular first molars in a southern Chinese subpopulation: a cone-beam computed tomographic study

Background

Cone-beam computed tomography (CBCT) was employed to study the morphology and curvature of middle mesial canals (MMCs) of mandibular first molars (MFMs).

Methods

CBCT scanning was performed on MFMs of 1100 patients. Patients' images that met the inclusion criteria were divided into group A (< 40 years old) and group B (≥ 40 years old) for further study. The images were used to study the incidence of MMCs at different ages, measure the curvature of MMCs in the mesiodistal and buccolingual directions using the Schneider method, and observe the anatomical morphology of the mesial root canal system. All statistical analyses were performed by using SPSS 21.0 software. Quantitative data were presented as mean ± standard deviation. Student’s t-test was used to calculate the statistical significance. P < 0.05 was considered statistically significant.

Results

In 875 patients, 1750 MFM images met the inclusion criteria. Among these cases, 158 MFMs contained an MMC, yielding an incidence rate of 9.03%. The incidence rate of MMCs was 11.22% in group A and 6.61% in group B, and this difference was statistically significant (P < 0.05). The curvature in the mesiodistal direction was 29.39 ± 8.53° in group A and 26.06 ± 8.50° in group B, and this difference was also significant (P < 0.05). The curved regions in groups A and B were often located in the middle 1/3 of canal. No significant difference in the distance between MMC orifices and mesiobuccal canal orifices or mesiolingual canal orifices was noted (P > 0.05). The most common mesial root canal morphological type was type II (3-2) (53.80%).

Conclusion

The incidence of MMCs in MFMs declined as age increased. The canal systems of MMCs were varied and complex, mainly exhibiting an obvious mesiodistal curve. CBCT is an outstanding method to help guide root canal therapy.

*Yeqing Yang and Buling Wu have contribute equally to this article.

Methods for measurement of root canal curvature: a systematic and critical review

The assessment of root canal curvature is essential for clinical and research purposes. This systematic review presents an overview of the published techniques for the measurement of root canal curvature features using imaging and to provide a critique of their clinical application. A database search in PubMed, PubMed Central, Embase, Scopus, EBSCO Dentistry & Oral Sciences Source and Virtual Health Library was conducted, using appropriate key words to identify measurement methods for root canal curvatures. The search strategy retrieved 10594 records in total, and 31 records fulfilled the inclusion criteria. From 2D image acquisitions, eleven studies measured exclusively the angle of curvature, an additional thirteen measured other curvature features (level, height, radius, length and shape). Seven reports described methods from 3D imaging (CBCT, μCT). Root canal curvatures should be measured, for clinical proposes, to facilitate endodontic treatment planning, and in research, to reduce the risk of selection bias. This review has revealed that there are many methods described in the literature; however, no consensus exists on which method should be used. Some of the methodologies have potential clinical translation, whereas others are suitable for research purpose only, as they require a specific software or radiographic exposure in the mesiodistal direction.

[Cone-beam computed tomography for determination of mesial root canal curvatures of human mandibular first molars]

OBJECTIVE

To investigate mesial root canal curvatures of human mandibular first molars using cone-beam computed tomography (CBCT).

METHODS

CBCT was performed for scanning the mandibular first molars of 1600 Chinese subjects, among whom the subjects identified to have middle mesial canals were divided into 5 age groups, namely group A (18-29 years), group B (30-39 years), group C (40-49 years), group D (50-59 years), and group E (60-80 years) for further analysis. All the CBCT images were reconstructed using Planmeca Romexis CBCT image reconstruction system, and the curvature of the mesial root was measured using the Schneider method.

RESULTS

A total of 2856 CBCT images were obtained from the 1600 subjects, among whom 168 (5.88%) were found to have middle mesial canals in the mandibular first molars. The prevalence of middle mesial canals was 37.50% in group A, 17.80% in group B, 14.88% in group C, 19.64% in group D, and 10.12% in group E. The moderate of the curvature in the mesiodistal direction was significantly higher in group A than in the other groups (P < 0.05); the curvature in mesiodistal direction differed significantly among the 5 groups (P < 0.05), and was the greatest in group A followed by group C and group D, and was the smallest in group E. The curvature in the buccolingual direction was similar among the 5 groups. The incidence of mesiodistal and buccolingual curvature of the middle mesial canals was significantly higher in the middle 1/3 of the root canal than in the upper 1/3 and apical 1/3 of the root canal.

CONCLUSIONS

The incidence of middle mesial canals in the mesial root of the mandibular first molars decreases with age. The middle mesial canal system of the mandibular first molar is complex and variable, and most of the first molars have obvious curvature in the mesiodistal and buccolingual directions. CBCT can provide reference for clinical treatment to reduce the treatment failure rate.