Apex Of Tooth Research Articles

Radiografía panorámica y tomografía computarizada de haz cónico para medir distancias entre ápices radiculares y estructuras anatómicas

Aim: To compare the accuracy of the panoramic radiography with cone-beam computed tomography (CBCT) scans in measuring the distances between root apexes and the adjacent anatomical structures including the maxillary sinus and the mandibular canal. Material and Methods: A total of 200 CBCT scans (100 maxillary and 100 mandibular) from patients who also had corresponding panoramic radiography were selected. Linear measurements (in mm) presenting centralized image were made between the apexes of the maxillary teeth and the inferior wall of the maxillary sinus, and between the apexes of the mandibular teeth and the superior border of the mandibular canal by using specific software for panoramic radiography and the measurements on the coronal sections in CBCT scans. Data were submitted to inferential statistical analysis and Student’s t-test for comparison between measurements. Results: CBCT scans were significantly more accurate than panoramic radiography to measure the distances between the apexes of the maxillary teeth and the inferior wall of the maxillary sinus (p<0.05) and between the apexes of the mandibular teeth and the superior border of the mandibular canal or mental foramen (p<0.05). Conclusion: CBCT scans present more accurate measurements than panoramic radiography.

Assessment of the Proximity of the Inferior Alveolar Canal with the Mandibular Root Apices and Cortical Plates-A Retrospective Cone Beam Computed Tomographic Analysis.

116 cone beam computed tomography (CBCT) scans were examined and the shortest distance of IAC with the root apices of mandibular canines, premolars and molars, and with cortical plates was analyzed. The data were statistically analyzed using SPSS. The shortest mean distance between IAC and lingual cortical plate (LCP) was found in the third molar area, and between IAC and buccal cortical plate (BCP) in the second premolar area. A high incidence of 60% direct communication (DC) was present in mandibular second molars; 38% in mandibular third molars; 13% in mandibular second premolars; 12% in mandibular first molars; and 1% in mandibular first premolars. Anteriorly, IAC was found to be significantly present in close approximation to the roots of mandibular canines. Posteriorly, IAC was found to be in significant proximity to the distal roots of mandibular second molars.

Evaluation of the distribution characteristics of the mandibular lingual foramen and its potential risks during implant surgery using cone-beam computed tomography a cross-sectional, retrospective study.

The lingual foramen is a risk factor for implantation and other mandibular surgeries, but there are few systematic studies on the anatomical and distribution characteristics of the lingual foramen in the entire mandible. A retrospective study was performed using 405 CBCT images. The anatomical characteristics and symmetrical distribution of the mandibular lingual foramen were analyzed. All patients had at least one lingual foramina. According to the positional relationship between the mandibular lingual foramen and the root apex of tooth, the mandibular lingual foramen is divided into the upper lingual foramen and the lower lingual foramen. Upper lingual foramen were divided into three types according to its running direction, namely Type 1 (Enters the mandible and descend in the direction of the lower edge of the mandible), Type 2 (Enters the mandible and descends in the direction of the lower edge of the mandible with branches), and Type 3 (It enters the mandible and divides into two branches, one ascends toward the crest of the alveolar ridge, and the other descends toward the lower edge of the mandible). And their respective prevalence are 84.0% [95% Tolerance Limit (TL) 81.2%-86.8%], 9.9% [95% TL 7.6%-12.1%], and 6.1% [95% TL 4.3%-8.0%]. In addition, the 81.8% [95% TL 79.0%-84.7%] of the upper lingual foramen is distributed in the central incisor area. Lower lingual foramen were divided into three categories according to the running direction, namely Category 1 (Enters the mandible and ascends toward the buccal bone plate), Category 2 (Enters the mandible and descends toward the buccal bone plate), and Category 3 (Go straight into the mandible toward the buccal bone plate). And their respective prevalence are 29.6% [95% TL 26.4%-32.7%], 50.9% [95% TL 47.5%-54.4%] and 19.5% [95% TL 16.8%-22.3%]. The frequency of lower lingual foramen distributed anteriorly to the mental foramen is 55.8% [95% TL 52.3%-59.2%], mid-mental foramen is 21.4%[95% TL 18.5%-24.2%], and posterior to the mental foramen is 22.8% [95% TL 20.0%-25.8%]. Both the upper and lower lingual foramina should be evaluated in the anterior, middle, and posterior regions of the mental foramen before implant surgeries.

Computed tomographic findings in 101 horses presented for the investigation of headshaking

SummaryBackgroundThe majority of horses presenting to a hospital with signs of headshaking receive a diagnosis of trigeminal‐mediated headshaking. This diagnosis is one of exclusion, so ruling out other possible causes of headshaking is essential.ObjectivesThe aims of this study were to describe the computed tomographic (CT) findings in horses that were presented for investigation of headshaking and underwent CT examination of the head under standing sedation. A secondary aim was to establish whether the proximity of the apices of the caudal maxillary cheek teeth to the infra‐orbital canal varied between age‐matched groups of horses presented for CT examination for investigation of headshaking and those presented for investigation of other conditions.Study designRetrospective case series of horses undergoing CT examination of the head as part of the investigation of headshaking at the Equine Centre, University of Bristol.MethodsCase records of horses that had standing CT images of the head obtained, reviewed and reported at the Equine Centre, University of Bristol over a 5‐year period (February 2012–March 2017) were reviewed. Cases that had presented for investigation of headshaking were included. The proximity of the apices of the maxillary cheek teeth to the infra‐orbital canal was assessed in age‐matched horses presenting for CT for investigation of headshaking and other reasons.ResultsA total of 101 horses presented for investigation of headshaking were included. There were four horses in which CT detected likely causative pathology for the headshaking which had not been identified by other diagnostic tests; however, radiographs had not been obtained in two of these horses. Three horses had periapical infection of the maxillary cheek teeth, and one horse had a fracture of the paracondylar process of the occipital bone. Clinical signs resolved following treatment in three horses; two with periapical infection and one with a paracondylar process fracture. One horse with periapical infection was lost to follow‐up. There was no significant difference in the proximity of the apices of the maxillary cheek teeth to the infra‐orbital canal between the head‐shaking and non‐head‐shaking groups.Main limitationsRetrospective study; pre‐selection of cases through discussion of the case and, in some instances assessment of videos of the behaviour, by the last author, prior to referral; lack of radiographs.ConclusionsWhilst trigeminal‐mediated headshaking is the most common cause of headshaking in horses, it is a diagnosis of exclusion so thorough investigation to rule out other possible causes is essential. We consider CT examination of the head to be a valuable tool in this investigation, although the diagnostic yield is likely to be low.

Malunion of Mandible Fracture: A Case Report

Radicular cysts are the most common odontogenic cystic lesions of jaws. They are asymptomatic lesions associated with the root apex of a non-vital tooth that slowly progresses rarely to large symptomatic swelling. Here we describe a patient with large radicular cyst involving maxillary sinus secondary to traumatized non-vital tooth 21 treated by surgical enucleation. Key words: Maxillary sinus, Radicular cyst, Surgical enucleation

Molecular Character of Mylonchulus hawaiiensis and Morphometric Differentiation of Six Mylonchulus (Nematoda; Order: Mononchida; Family: Mylonchulidae) Species Using Multivariate Analysis

Mononchida members are predatory nematodes with the potential to reduce the number of plant-parasitic nematodes in the soil. During a survey on Mononchida in Iran, several populations of Mylonchulus were recovered from various localities. A population of M. hawaiiensis was studied using 18S rDNA. The phylogenetic analysis using Bayesian inference placed the sequenced M. hawiinesis (OP210758) together with other M. hawaiiensis from Japan (AB361438-AB361442) with a 1.00 posterior probability support. In addition, morphological differences between six Mylonchulus (Nematoda; order: Mononchida; Family: Mylonchulidae) populations were investigated in Iran using discriminant analyses (DA), PERMANOVA, and principal coordinate analysis (PCoA). The purpose was to evaluate the efficacy of PCoA and DA in separating the Mylonchulus species, namely M. sigmaturus, M. paitensis, M. lacustris, M. brachyuris, M. kermaninesis, and M. hawaiiensis. To achieve this, 16 morphometric measurements (body length, a, b, c, c′, V, G1, G2, buccal cavity length, buccal cavity width, dorsal tooth apex, dorsal tooth length, neck length, amphid from anterior end, rectum, and tail length) were made on 160 specimens. The analysis of variance showed that all features were significantly different among the species, except a, b, and the amphid position from the anterior end and tail length. The stepwise discriminant analysis revealed that body length, tail length, neck length, and c′ value were the four most discriminating variables useful to distinguish clearly the six species of Mylonchulus. The variables with strong discriminatory power correctly classified 98.87% of individuals from Iran’s sample of known Mylonchulus species. The results provide a morphometric basis for effectively distinguishing Mylonchulus species.

Morphometric study for the localization of the mental foramen in relation to the vertical reference plane.

The mental foramen (MnF) is the anatomic landmark where the mental neurovascular bundle exits the mandible. Precisely determining the position of the MnF is necessary before all dentoalveolar therapeutic procedures performed in the mandibular premolar area. For the study, we performed two ex vivo direct morphometric determinations on dry human dentate and edentate mandibles, and two in vivo imaging morphometric determinations through cone-beam computed tomography (CBCT) and orthopantomography (OPG) in dentate human patients. The following landmarks were used to locate the MnF: the distance between the MnF and the superior border of the mandible (MnF-SB), the distance between the MnF and the inferior border of the mandible (MnF-IB), and the position of the MnF in relation to the root apices of the posterior teeth. The results obtained from these data were processed statistically using the analysis of variance (ANOVA). By direct morphometry on dentate mandibles, the MnF was situated closer to the IB and by direct morphometry on completely edentulous mandibles, the MnF was located closer to the SB. In both direct morphometry studies, the MnF transverse diameter was larger than the vertical one, with the MnF having an oval shape. ANOVA for both direct morphometry studies showed that the distances MnF-IB and MnF-SB significantly vary statistically with interactions and depending on age (p<0.00001). The vertical diameter of the MnF significantly varies statistically depending on age, interactions and between studies, and its transverse diameter varies statistically significantly with interactions and depending on age (p<0.00001). According to OPG and CBCT imaging studies, the MnF was located closer to the IB, and the transverse diameter of the MnF was larger than the vertical diameter; such results are similar to the direct morphometry study performed on dry dentate human mandibles. Regarding the position of the MnF in relation to the root apices, it was most frequently located inferior to the root apices in 79.45% of cases, in 19.23% of cases it was located at the root apices level and in 1.31% of cases it was located superior (coronal) to the root apices. ANOVA for both imaging morphometry studies showed that the MnF-IB distance varies statistically significantly with the interactions, the study, the sex of the patients and their age, the MnF-SB distance varies statistically significantly with the interactions, the study and the patients' age (p<0.05), and the MnF diameters vary statistically significantly with interactions and patient age (p<0.05). The results of this study can help dental practitioners in improving dentoalveolar surgery procedures in the posterior mandible.

Mechanical Behavior of Human Cancellous Bone in Alveolar Bone under Uniaxial Compression and Creep Tests.

In the process of orthodontic treatment, the remodeling of cancellous bone in alveolar bone (in this paper, cancellous bone in alveolar bone is abbreviated as CBAB) is key to promoting tooth movement. Studying the mechanical behavior of CBAB is helpful to predict the displacement of teeth and achieve the best effect of orthodontic treatment. Three CBAB samples were cut from alveolar bone around the root apex of human teeth. A uniaxial compression test was used to study the transient elastic properties of CBAB. A creep test was used to study the time-dependent viscoelastic properties of CBAB. Both tests were carried out at the loading rates of 0.02 mm/min, 0.1 mm/min and 0.5 mm/min. The results revealed that CBAB is a nonlinear viscoelastic and hyperelastic material. The stress–strain curve obtained from the uniaxial compression test could be divided into three stages: the collapse stage of the front section, the exponential stage of the middle section and the almost linear stage of the rear end. According to the strain–time curve obtained from the compression creep test, a trend of increasing strain over time was relatively obvious within the first 30 s. After 200 s, the curve gradually tended to plateau. Four hyperelastic models and three viscoelastic models were used to fit the test data. Finally, the fifth-order polynomial hyperelastic model (coefficient of determination “R2 > 0.999”) was used to describe the hyperelastic properties of CBAB, and the seven-parameter model of the generalized Kelvin modified model (“R2 > 0.98”) was used to describe the viscoelastic properties of CBAB.

Evaluation of irrigant extrusion following the use of different root canal irrigation techniques: A systematic review and meta-analysis.

This systematic review investigates whether different irrigation techniques have different effects on irrigant extrusion from mature tooth apices. Articles published between January 2000 and January 2022 were searched in six electronic databases (MEDLINE, Embase, Google Scholar, Web of Science, Scopus and Cochrane) using appropriate keywords. Overall, 2265 articles were screened by their titles and abstracts. Fifty-six full-text articles were selected based on the inclusion criteria. Of them, 17 in vitro studies were included in the systematic review and meta-analysis. The meta-analysis was conducted using the random-effects inverse variance method. The results showed that the negative pressure technique caused a lesser amount (p= 0.00) and frequency (p= 0.00) of extrusion than the open-ended needle irrigation. Sonic and ultrasonic activation caused less amount of extrusion than both open-ended (p= 0.00 or p= 0.01) and closed-ended needle (p= 0.00) irrigation.

CENTRAL OSSIFYING FIBROMA IN JAW: A CASE REPORT

Central ossifying fibroma is considered a benign, slow-growing fibro-osseous lesion with a predilection for middle-aged women. On imaging exams, the lesion can be uni- or multilocular, radiolucent, mixed, or radiopaque. The aim of this study is to report a case of central ossifying fibroma. A 57-year-old Black sought consultation for increased volume in the mandibular right region. On examination, a slight bulging in the bottom of alveolar mucosa near tooth 47, without changes in the mucosa. On radiographic examination, the presence of a hyperdense mass with a radiolucent halo of approximately 2 cm in the mandibular body associated with the apex of tooth 47 was observed. Incisional biopsy confirmed the suspicion of central ossifying fibroma. As a form of treatment, surgical excision and curettage were performed under general anesthesia. The patient is being followed up and has no pain and functional complaints at the moment. Central ossifying fibroma is considered a benign, slow-growing fibro-osseous lesion with a predilection for middle-aged women. On imaging exams, the lesion can be uni- or multilocular, radiolucent, mixed, or radiopaque. The aim of this study is to report a case of central ossifying fibroma. A 57-year-old Black sought consultation for increased volume in the mandibular right region. On examination, a slight bulging in the bottom of alveolar mucosa near tooth 47, without changes in the mucosa. On radiographic examination, the presence of a hyperdense mass with a radiolucent halo of approximately 2 cm in the mandibular body associated with the apex of tooth 47 was observed. Incisional biopsy confirmed the suspicion of central ossifying fibroma. As a form of treatment, surgical excision and curettage were performed under general anesthesia. The patient is being followed up and has no pain and functional complaints at the moment.

Enriching our knowledge of Late Cretaceous wetland plant communities: Zlatkovia crenulata gen. et sp. nov., an amphibious angiosperm from the St. Mary River Formation, Alberta, Canada

Sixty-seven coalified compression specimens of leaves, one attached to a stem, have been found in the St. Mary River Formation (uppermost Campanian–lowermost Maastrichtian, Upper Cretaceous) near Cardston, Alberta, Canada. Leaves have long multi-veined petioles with clasping bases, and an ellipsoid to obovate lamina with a convex to almost flat apex, and a crenate margin with one order of convex-convex chloranthoid teeth with angular sinuses. Tooth apices often end in a small concavity interpreted as a hydathode. Several primary veins enter the lamina in a flabellate manner. The central primary vein branches pinnately while lateral primaries, dichotomize toward the margin producing a reticulodromous pattern of secondaries. Secondaries arising from the lateral primary veins are the result of consistent dichotomies and anastomoses with a concurrent loss of gauge. Tertiary veins are alternate percurrent, and quaternaries form an irregular reticulate fabric. Quaternary veins form polygonal areoles with freely ending veinlets. Some specimens show a polygonal pattern of sub-epidermal aerenchyma like that of many other aquatics. Plants are compared to other fossil aquatic taxa, including those from the St. Mary River Formation and extant members of Ranunculaceae, Menyanthaceae and Nymphaeaceae. The specimens are described as a new amphibious aquatic: Zlatkovia crenulata Rothwell & Stockey gen. et sp. nov., eudicot family incertae sedis. This assemblage meaningfully enriches our understanding of aquatic and adjacent wetland habitats near the close of the Cretaceous, and emphasizes that the structure of modern wetland communities was well established before the end of the Mesozoic.

Nonsyndromic supernumerary teeth in patients in National Taiwan University Children's hospital

Background/purposeA literature review reveals limited data for supernumerary teeth in Taiwan. This study aimed to analyze the characteristics of nonsyndromic supernumerary teeth in patients in the National Taiwan University Children's Hospital. Materials and methodsThis retrospective study analyzed the nonsyndromic supernumerary teeth in 1280 patients (710 boys and 570 girls) based on examination of mainly panoramic radiographs and related radiographs. Chi-square test was used for trend analysis. ResultsThe incidence of nonsyndromic supernumerary teeth was 11.25% (179 supernumerary teeth in 144 of the 1280 patients). There was a male predominance (4.33: 1, P < 0.0001) for our 144 patients. Most supernumerary teeth were single (63.69%), conical-shaped (78.77%), and unerupted (77.09%). Supernumerary teeth also tended to be located in the premaxilla (93.85%), fully developed (51.40%), invertedly oriented (45.25%), sagittally located in a palatal/lingual position (67.60%), and adjacent to the root and root apex of permanent teeth (70.39%). The supernumerary teeth with a normal orientation (64.52%) had a high potential to erupt into the oral cavity, but the majority of the supernumerary teeth with a transverse orientation (97.22%) or an inverted orientation (100%) were unerupted. ConclusionThe nonsyndromic supernumerary teeth occur most commonly in male patients with a male to female ratio of 4.33: 1. The incidence of nonsyndromic supernumerary teeth in our 1280 patients is 11.25%, and the most frequent location of supernumerary teeth is the anterior maxillary region. More than three quarters of supernumerary teeth are conical-shaped or unerupted. Inverted supernumerary teeth are all embedded in the jawbones.

Assessment of the vertical relationship between the maxillary posterior teeth and the maxillary antral floor in a South Indian population using Cone Beam Computed Tomography- A radiographic observational study

Introduction and Aim: Maxillary sinus, also known as the Antrum of Highmore, is said to be one of the largest pyramidal shaped paranasal sinuses that begins at the 10th week of intrauterine development and undergoes pneumatisation. The root apices of the maxillary posterior teeth have a proximity to the antral floor, so a thorough understanding of this anatomical relationship is very essential as it can have an important influence during dental procedures such as implant planning, extractions, and certain other oral and maxillofacial surgeries. The aim of this study was to assess the vertical relationship between the posterior teeth in the maxillary arch with the floor of the maxillary antrum, using Cone Beam Computed Tomography (CBCT) in a South Indian population. Materials and Methods: This was a retrospective analysis of 50 right or left maxillary sinuses in panorama and tangential sections by tracing the outline forms of the maxillary antral floor and also measuring its vertical distance from maxillary posterior root apices. Results: Four types of relationship patterns were observed between the maxillary antral floor and root apices of the maxillary posteriors. The root apices of the maxillary second molar were found to be in close proximity with the maxillary sinus (2.27mm) and similar observation was found in the left side with the left second molar to be in close proximity to the sinus (2.04 mm). Conclusion: The assessment of this vertical relationship is very important during extractions, implant planning or during any other surgeries in the maxillofacial region.

Dental anatomy and replacement patterns in the early Permian stem amniote, Seymouria.

The exquisite preservation of maxillary and mandibular fragments of Seymouria has allowed us to examine for the first time in detail the dental anatomy and patterns of development in this stem amniote. The results obtained through histological examination show that Seymouria has pleurodont implantation with ankylosis of the tooth to the labial side of the jawbone. The dentary and maxillary teeth exhibit similar dental characteristics, such as the attachment bone (alveolar bone) and cementum rising above the jawbone on the base of the tooth, and smooth carinae extending lingually toward the tooth apex. Additionally, the clear presence of plicidentine, infolding of dentine into the pulp cavity, was found within the tooth root extending into the tooth crown. Lastly, the tooth replacement pattern is alternating, illustrating that Seymouria retains the classic primitive condition for tetrapods, a pattern that is continued in amniotes. Our results provide an important basis for comparison with other stem amniotes and with amniotes.

Detection Rate and Variability in Measurement of Mandibular Incisive Canal on Cone-Beam Computed Tomography: A Study of 220 Dentate Hemi-Mandibles from Italy

The mandibular incisive canal (MIC) is a small bony channel located in the interforaminal region; it represents the anterior continuation of the mandibular canal. Cone-beam computed tomography (CBCT) is the most commonly utilized radiological technique for assessing the MIC. The main purpose of this study was to evaluate the detectability and variability in measurements of the MIC on CBCT. A total of 220 dentate hemi-mandibles were retrospectively selected for this study. For each hemi-mandible, the detectability, diameter, and distance of the MIC from anatomical landmarks (cortical plates and tooth apices) were evaluated in consensus by two observers. The analysis was performed at four different levels (first premolar, canine, lateral incisor, and central incisor) and was repeated after one month. The variability of MIC measurements was expressed as the coefficient of repeatability (CR), obtained from the Bland–Altman analysis. The MIC detection rate reduced from the first premolar to the central incisor (from 82.3% to 0.5%). The CR of MIC measurements (diameter and distances from anatomical landmarks) was ≤0.74 mm. Although the MIC is difficult to detect in a non-negligible percentage of cases, the limited variability in measurements confirms that CBCT is an effective technique for the assessment of the MIC.

Inferior alveolar nerve topography and its bifurcation features: a cone beam computed tomography evaluation.

Mandibular canal (MC) is the most important vital structure in mandible to prevent from complications such as bleeding and paresthesia. The aims of the present study were to inform the features (diameter, distances to the mandibular borders, and distance to tooth apex) of the MC for each posterior tooth region, and to present the bifurcation features of the MC. Four-hundreds-eighteen MC images of 209 patients were evaluated. The parameters were recorded from right and left hemi-mandibles for each posterior teeth region: 1) MC diameter; 2) MC and mandibular basis distance; 3) MC and crest distance; 4) MC and tooth apex distance; 5) MC and buccal plate distance; 6) MC and lingual plate distance; and 7) possible implant length (the distance between 2 mm coronal of the MC and 1 mm apical of the crest). Additionally, MC bifurcation type and bifid mandibular canal length were noted for right and left sides. While higher MC diameter values were recorded at molars, MC diameter in first premolars bilaterally were the lowest. In premolars, MC and mandibular basis distance showed higher values than molars. There was a trend of decrease in MC and crest distance from molars to premolars. The highest MC and tooth apex distance was measured in second molar; however, the lowest was in the first premolar. Additionally, MC and buccal plate distances were higher in molars, while MC and lingual plate distances were higher in premolars. Possible implant length in first premolar was the lowest, when it was the highest in second molars. For simulating overall MC topography, it extended bucco-coronally from molars to premolars. Due to this topography, possible implant length increased from premolars to molars.

Apexification of permanent immature teeth using MTA – a report of cases

Immature permanent teeth with necrotic pulp require endodontic treatment different than conventional procedure. Proper root canal treatment and correct filling of such teeth is hardly possible due to open wide apices. Apexification is a method that enables to create hard apical barrier. Until recently the most common material in this method was calcium hydroxide. It is highly effective, however using calcium hydroxide requires long time treatment up to 24 months with many appointments to create mineral apical barrier. This may lead to fracture of the root`s thin walls end tooth extraction. Currently, the MTA (Mineral Trioxide Aggregate) preparation is recommended in the apexification procedure to close open apex of immature teeth. It enables to carry out apexification procedure during one or two appointments. The aim of this study is to describe 5 cases of apexification in posttraumatic and due to caries non-vital immature teeth using MTA. In the following period of observation in all the presented cases a positive treatment result was obtained. In all the presented cases a positive treatment result was obtained.

Cone Beam Computed Tomography based evaluation of position of mental foramen and its relation to apices of mandibular posterior teeth in a sample of Pakistani population.

To radiographically determine the mental foramen position, its distance to the nearest apex and the prevalence of anterior loop of mandibular nerve using cone-beam computed tomography scans. The cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, from January to June 2020, and comprised cone-beam computed tomography scans of males or females of Pakistani origin aged 15-65 years with intact mandibular dentition and fully formed roots with matured apex. The scans were analysed to determine the horizontal position of mental foramen and to classify it according to the Tebo and Telford classification. The vertical distance from mental foramen to the nearest tooth apex was measured and the mandibular nerve configuration was determined. Data was analysed using SPSS 23. Among the 96 scans, the most frequent location of mental foramen MF was along the long axis of 2nd premolars for both right 50(52.1%) and left 49(51%) sides, followed by between 1st and 2nd premolars for both right 28(29.2%) and left 38(39.6%) sides. The mean minimum distance from mental foramen to the nearest root apex was 3.75±2.59mm and 3.99±2.26mm on right and left sides, respectively. There was bilateral symmetry on both sides. The most frequent mandibular nerve configuration on the right 69(72.6%) and left 75(78.1%) sides, with anterior loop being the least common; right side 3(3.2%) and 5(5.2%) left side. The most common position of mental foramen was along the long axis of 2nd premolars while the anterior loop was the least common.

Comparative effects of erbium-doped yttrium aluminum garnet laser, the shock wave-enhanced emission photoacoustic streaming, and the conventional needle irrigation on apical extrusion of irrigants

ObjectivesThis study compared the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser with the shockwave-enhanced emission photoacoustic streaming (SWEEPS) protocol and the conventional needle irrigation (CNI) on extrusion of irrigants through the root apex of molar teeth with different apical diameters. Materials and methodsIn this ex vivo experimental study, access cavities were prepared in 120 extracted maxillary and mandibular molars in 12 groups of conventional needle irrigation (CNI), auto-SWEEPS, ultra-short pulse (USP), and super-short pulse (SSP), each with 0.25, 0.4 and 0.8 mm apical diameters (n = 10). The root canals were prepared and mounted in resin blocks. Periodontal pressure was simulated by a capillary tube of water in the apex. The volume of extruded irrigant was quantified spectrophotometrically, and analyzed by the Kruskal-Wallis test. ResultsApical extrusion in CNI was the same in the three apical diameters, and was maximum compared with others groups. The amount of extruded irrigant through the apex was different among the three apical diameters in auto-SWEEPS (P = 0.002) and USP (P = 0.001) modes. The SSP mode caused maximum extrusion of irrigant with no significant difference among different apical diameters (P = 0.681) followed by auto-SWEEPS. The USP mode caused the lowest extrusion in 0.25 mm diameter (P = 0.006). In auto-SWEEPS, 0.25 mm diameter had a significant difference with 0.8 mm. In USP, 0.25 mm had a significant difference with 0.4 and 0.8 mm diameters. In 0.25 mm, USP and SSP (P < 0.05), and USP and auto-SWEEPS (P < 0.05) had significant differences. In 0.4 mm, only SSP and USP had a significant difference (P < 0.05). Conclusion. CNI with a 27-gage needle caused greater irrigant extrusion than the SWEEPS modes. The USP mode caused minimum extrusion of irrigant.

Decoding family-level features for modern and fossil leaves from computer-vision heat maps.

Angiosperm leaves present a classic identification problem due to their morphological complexity. Computer-vision algorithms can identify diagnostic regions in images, and heat map outputs illustrate those regions for identification, providing novel insights through visual feedback. We investigate the potential of analyzing leaf heat maps to reveal novel, human-friendly botanical information with applications for extant- and fossil-leaf identification. We developed a manual scoring system for hotspot locations on published computer-vision heat maps of cleared leaves that showed diagnostic regions for family identification. Heat maps of 3114 cleared leaves of 930 genera in 14 angiosperm families were analyzed. The top-5 and top-1 hotspot regions of highest diagnostic value were scored for 21 leaf locations. The resulting data were viewed using box plots and analyzed using cluster and principal component analyses. We manually identified similar features in fossil leaves to informally demonstrate potential fossil applications. The method successfully mapped machine strategy using standard botanical language, and distinctive patterns emerged for each family. Hotspots were concentrated on secondary veins (Salicaceae, Myrtaceae, Anacardiaceae), tooth apices (Betulaceae, Rosaceae), and on the little-studied margins of untoothed leaves (Rubiaceae, Annonaceae, Ericaceae). Similar features drove the results from multivariate analyses. The results echo many traditional observations, while also showing that most diagnostic leaf features remain undescribed. Machine-derived heat maps that initially appear to be dominated by noise can be translated into human-interpretable knowledge, highlighting paths forward for botanists and paleobotanists to discover new diagnostic botanical characters.