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European Journal of Dentistry May 2021The aim of the present study was to evaluate the surface roughness (SR) of various nickel-titanium (NiTi) rotary endodontic instruments (ProTaper Next [PTN], WaveOne...
OBJECTIVES
The aim of the present study was to evaluate the surface roughness (SR) of various nickel-titanium (NiTi) rotary endodontic instruments (ProTaper Next [PTN], WaveOne Gold [WOG], and ProTaper Gold [PTG]) before and after root canal instrumentation.
MATERIALS AND METHODS
For each type (PTN, WOG, and PTG), the endodontic instrumentation was performed using extracted mandibular molar teeth's curved mesial root canals (curvature: 20-40 degrees) after determining the working length. Each NiTi file was cleaned, and sterilized following preparation of four root canals and characterized for surface properties before and after endodontic instrumentation using a contact-mode three-dimensional surface profiler. The data were analyzed statistically using Statistical Package for the Social Sciences for SR parameters including average surface roughness value (Sa), root mean square roughness (Sq), and peak to valley height (Sz).
RESULTS
Preinstrumentation assessment revealed a significant difference for all the three SR variables < 0.05) for the cutting blade and the flute area. WOG instruments showed the highest SR values ( = 0.000). The postinstrumentation assessment revealed significant differences in SR values in the blade and the flute between the three groups ( < 0.05), with WOG and PTG exhibiting the highest values in the blade and flute sections, respectively.
CONCLUSIONS
The SR parameters of intact PTN, WOG, and PTG NiTi files vary and that was increased following the endodontic instrumentation.
PubMed: 33111285
DOI: 10.1055/s-0040-1718469 -
Journal of Dental Sciences Apr 2022As the number of patients with osteoporosis requiring orthodontic treatment is increasing with the aging of society, it is necessary to evaluate the relations between...
BACKGROUND/PURPOSE
As the number of patients with osteoporosis requiring orthodontic treatment is increasing with the aging of society, it is necessary to evaluate the relations between bone metabolism in old age and orthodontic tooth movement (OTM). However, the effects of changes in bone metabolism due to osteoporosis on OTM and root resorption are still unclear. Therefore, we investigated the effects of OTM and root resorption in a mouse ovariectomy (OVX)-induced osteoporosis model.
MATERIALS AND METHODS
Eight-week-old female wild-type mice underwent OVX or sham surgery (Sham) as controls. One month after treatment, a nickel titanium coil spring was used to apply a mesial force to the maxillary left first molars of OVX or Sham mice for 12 days. The distance between the maxillary first molar and the second molar changed due to OTM and osteoclast formation was evaluated. The odontoclast formation and root resorption along the root surface of the distobuccal root of the first molar was also evaluated by histological analysis and scanning electron microscopy.
RESULTS
Distance of tooth movement and osteoclast formation were significantly increased in OVX mice compared to Sham controls. Furthermore, root resorption in the mesial surface of the distal molars induced by orthodontic force was significantly increased in OVX mice.
CONCLUSION
The amount of OTM was significantly increased, and the accompanying root resorption was also increased in OVX mice. Therefore, attention should be paid to the risk of root resorption associated with orthodontic treatment in patients with osteoporosis.
PubMed: 35756770
DOI: 10.1016/j.jds.2021.11.009 -
The Angle Orthodontist May 2016To develop a method to quickly estimate the location of center of resistance (CR) in mesial-distal (MD) and buccal-lingual (BL) directions from the tooth's image.
OBJECTIVE
To develop a method to quickly estimate the location of center of resistance (CR) in mesial-distal (MD) and buccal-lingual (BL) directions from the tooth's image.
MATERIALS AND METHODS
The maxillary cone-beam computed tomography (CBCT) scans of 18 patients were used. Finite element (FE) models of the canines and their surrounding tissues were built based on their CBCT scans to calculate the locations of CR. Root length, centroid of the contact surface (CCS), and centroid of projection of the contact surface (CPCS) were also obtained from the images. The CCS and CPCS locations were projected on the tooth's long axis, which were represented as percentages of the root length measured from the root's apex.
RESULTS
Using the FE results as the standards, the errors of using CCS or CPCS to estimate CR were calculated. The average location of CR calculated using the FE method was 60.2% measured from the root's apex in the MD direction and 58.4% in the BL direction. The location of the CCS was 60.9%. The difference in CR was 0.7% in the MD direction and 2.5% in the BL direction. The location of CPCS was 60.2% in the MD direction and 59.1% in the BL direction, which resulted in a 0.1% and 0.8% difference with the reference CR, respectively. The average difference of CR in the MD and BL directions was small but statistically significant (P < .05).
CONCLUSION
The locations of the CR of a human canine in the MD and BL directions can be estimated by finding the CPCSs in those directions.
Topics: Cone-Beam Computed Tomography; Cuspid; Humans; Incisor; Tooth Root; Tooth, Impacted
PubMed: 26401827
DOI: 10.2319/051215-322.1 -
Cureus Jul 2022External cervical resorption (ECR) is a dynamic pathological process characterized by its cervical position on the root and arises below the epithelial attachment and...
External cervical resorption (ECR) is a dynamic pathological process characterized by its cervical position on the root and arises below the epithelial attachment and the coronal part of the bone. This report will highlight a case of ECR in an asymptomatic patient. A radiolucent area was noted during a routine dental follow-up examination on the bitewings at the mesial surface of the upper right second premolar. Persistently, the radiolucency had multiple radiographic views indicating a true form of a lesion that could be diagnosed as external cervical resorption. The patient did not report any complaints since dental treatment was completed in 2016. After a series of radiographs and conducting further diagnostic measures, a diagnosis of ECR was confirmed. The best treatment of choice for this case was extraction and restoring the missing tooth with an implant-supported crown. The size and the extent of such a defect could affect the strategy for implant placement. This paper aimed to report that ECR can be asymptomatic for a long time with advanced cervical root resorption in some cases.
PubMed: 36043004
DOI: 10.7759/cureus.27334 -
The Journal of Clinical Pediatric... 2019: To determine the three-dimensional (3D) tooth morphology of all primary molars and to identify and consolidate positional factors that could potentially have an effect...
: To determine the three-dimensional (3D) tooth morphology of all primary molars and to identify and consolidate positional factors that could potentially have an effect on tooth preparation. : Thirty-one non-carious primary molars were scanned using micro-CT and reconstructed using 3D analysis software. Each pulp horn to its respective cusp tip distance (PHCD) was measured as well as the distances from the pulp chamber to the mesial, distal, lingual and buccal surfaces. One-way ANOVA and post-hoc t-tests were used for data analysis. : The mesio-buccal and disto-buccal PHCD was significantly shorter than the mesio-lingual and disto-lingual PHCDs in maxillary second primary molars (P < 0.05). Mesial, distal and lingual walls were thinner than the buccal walls of mandibular molars while in maxillary molars; the mesial and distal walls were thinner than the palatal and buccal walls (P < 0.05). : First primary molars have thinner tooth structure surrounding the pulp than second primary molars in the same arch with the exception of the buccal walls of all molars and lingual walls of maxillary molars. The mesial and distal walls are thinner than the buccal walls of all molars and lingual walls in maxillary molars.
Topics: Dental Pulp Cavity; Molar; Tooth Root; Tooth, Deciduous; X-Ray Microtomography
PubMed: 31657990
DOI: 10.17796/1053-4625-43.6.4 -
Frontiers in Neurology 2021In people with drug resistant epilepsy (DRE), seizures are unpredictable, often occurring with little or no warning. The unpredictability causes anxiety and much of the...
In people with drug resistant epilepsy (DRE), seizures are unpredictable, often occurring with little or no warning. The unpredictability causes anxiety and much of the morbidity and mortality of seizures. In this work, 102 seizures of mesial temporal lobe onset were analyzed from 19 patients with DRE who had simultaneous intracranial EEG (iEEG) and scalp EEG as part of their surgical evaluation. The first aim of this paper was to develop machine learning models for seizure prediction and detection (i) using iEEG only, (ii) scalp EEG only and (iii) jointly analyzing both iEEG and scalp EEG. The second goal was to test if machine learning could detect a seizure on scalp EEG when that seizure was not detectable by the human eye (surface negative) but was seen in iEEG. The final question was to determine if the deep learning algorithm could correctly lateralize the seizure onset. The seizure detection and prediction problems were addressed jointly by training Deep Neural Networks (DNN) on 4 classes: non-seizure, pre-seizure, left mesial temporal onset seizure and right mesial temporal onset seizure. To address these aims, the classification accuracy was tested using two deep neural networks (DNN) against 3 different types of similarity graphs which used different time series of EEG data. The convolutional neural network (CNN) with the Waxman similarity graph yielded the highest accuracy across all EEG data (iEEG, scalp EEG and combined). Specifically, 1 second epochs of EEG were correctly assigned to their seizure, pre-seizure, or non-seizure category over 98% of the time. Importantly, the pre-seizure state was classified correctly in the vast majority of epochs (>97%). Detection from scalp EEG data alone of surface negative seizures and the seizures with the delayed scalp onset (the surface negative portion) was over 97%. In addition, the model accurately lateralized all of the seizures from scalp data, including the surface negative seizures. This work suggests that highly accurate seizure prediction and detection is feasible using either intracranial or scalp EEG data. Furthermore, surface negative seizures can be accurately predicted, detected and lateralized with machine learning even when they are not visible to the human eye.
PubMed: 34867707
DOI: 10.3389/fneur.2021.705119 -
BMC Oral Health Aug 2021Optimal utilization of dental caries data is crucial in epidemiological research of individuals with juvenile idiopathic arthritis (JIA). The aims were to: explore...
BACKGROUND
Optimal utilization of dental caries data is crucial in epidemiological research of individuals with juvenile idiopathic arthritis (JIA). The aims were to: explore whether caries is more prevalent among children and adolescents with JIA compared to controls; examine presence of caries according to JIA group, socio-behavioral and intraoral characteristics, and the extent to which surface-specific caries varies between and within individuals; assess whether surface-specific caries varies according to JIA group and dentition; and investigate whether disease-specific clinical features of JIA are associated with presence of caries.
METHODS
In this comparative cross-sectional study, calibrated dentists examined index teeth (primary 2. molars, 1. permanent molars) of 4-16-year-olds with JIA (n = 219) and matched controls (n = 224), using a detailed caries diagnosis system (including enamel caries). JIA-specific characteristics were assessed by pediatric rheumatologists and socio-behavioral information collected by questionnaires. Multilevel mixed-effect logistic regressions reporting odds ratios (OR) with 95% confidence interval (CI) were applied (caries at surface level as outcome variable). Potential confounders were adjusted for, and the effect of dependency of surface-specific caries data was estimated by calculating intra-class correlation coefficients (ICC).
RESULTS
At individual level, no significant difference in caries prevalence was found between individuals with JIA and controls, regardless of inclusion of enamel caries. Proportion of enamel lesions exceeded dentine lesions. JIA was not associated with presence of caries, but in both groups, low maternal educational level was associated with presence of caries (OR: 2.07, 95% CI: 1.24-3.46). Occlusal and mesial surfaces, compared to buccal surfaces, had generally higher OR according to presence of caries than distal and lingual surfaces (ICC = 0.56). Surface-specific caries in the permanent dentition differed significantly according to group affiliation. Some JIA disease-specific variables were suggested to associate with presence of caries.
CONCLUSIONS
No overall difference in caries prevalence between individuals with JIA and controls was observed, but for both groups, low maternal educational level and tooth surface associated with presence of caries. Associations between JIA disease-specific variables and presence of caries cannot be excluded. Due to predominance of enamel lesions, the potential of preventative dental strategies is considerable.
Topics: Adolescent; Arthritis, Juvenile; Child; Cross-Sectional Studies; Dental Caries; Dentition, Permanent; Humans; Multilevel Analysis; Tooth, Deciduous
PubMed: 34433437
DOI: 10.1186/s12903-021-01758-y -
Diagnostics (Basel, Switzerland) Jun 2022Periodontitis causes attachment and alveolar bone loss; hence, this study aimed to determine the prevalence, frequency, and pattern of bone loss at first molar-incisor...
BACKGROUND
Periodontitis causes attachment and alveolar bone loss; hence, this study aimed to determine the prevalence, frequency, and pattern of bone loss at first molar-incisor areas using Cone Beam Computed Tomography (CBCT) images.
METHODS
A retrospective, cross-sectional analysis was conducted of 250 randomly selected CBCT images of clearly defined full arches of patients aged from 18 to 70 years who were divided into six age groups and into male and female groups. Four sites around each tooth were scanned at several accesses for bone loss detection. Distance beyond 2 mm apical to the cementoenamel junction to the level of the remaining bone was considered to indicate bone loss. The Shapiro-Wilk test was used to test the normality of the data, and statistical tests were applied for data analysis at the 0.05 -value level.
RESULTS
The rate and amount of bone loss within the examined sample were relatively high. The examined images generally revealed a higher rate of bone loss on proximal than on labial/buccal and lingual/palatal surfaces of the first upper and lower molars. The highest amount of bone loss among all the teeth scanned in this study was seen on the mesial and distal bone of mandibular incisors, 4.36 mm and 4.31 mm, respectively, exceeding that in the labial and lingual bone, 3.23 mm and 1.89 mm, respectively, and it was highly horizontal rather than vertical in pattern.
CONCLUSIONS
Based on 250 randomly selected CBCT images of clearly defined, full upper and lower arches scanned for this study, it was concluded that the rate and amount of horizontal bone loss were less than vertical bone loss and was focused mainly in the interproximal areas of the first molars. However, the highest recorded amount of bone loss was at the proximal and labial aspects of the mandibular incisors. Furthermore, younger age groups displayed significantly higher rates and amounts of bone loss than older groups, with a slight predilection for males.
PubMed: 35885442
DOI: 10.3390/diagnostics12071536 -
PloS One 2023Fractal dimension (FD) analysis has been proposed and validated in osseointegration-related research. The aim of this study was to evaluate the feasibility of FD...
BACKGROUND
Fractal dimension (FD) analysis has been proposed and validated in osseointegration-related research. The aim of this study was to evaluate the feasibility of FD analysis in the osteogenesis detection of bone substitute materials (BSMs) of Bio-Oss in maxillary lateral sinus augmentation.
METHODS
Patients who received lateral maxillary sinus augmentation and underwent grafting with BSMs (Bio-Oss) were included in the study. The cross sections of the BSMs under cone-beam computed tomography (CBCT) at mesial, distal, and sagittal directions were obtained immediately after the graft (T0) and 6 months later (T1), and the obtained images were cropped to include only the BSMs. The FD analysis was performed, and the FD value was obtained by the method of box-counting. Paired t-tests and analysis of variance (ANOVA) were used, and p-values <0.05 was considered statistically significant.
RESULTS
Twelve participants with 22 implants, which were inserted simultaneously after sinus augmentation, were included in this study. A total of 22 mesial, 22 distal, and 14 sagittal images were obtained after FD analysis. The mean FD value and standard deviation at T0 was 1.2860 ± 0.0896, while at T1, it was 1.2508±0.1023; thus, significant differences were detected (p = 0.022). However, the increasing or decreasing trend of FD value was not stable, and no significant difference was detected for FD values of mesial, distal, and sagittal images between T0 and T1. ANOVA indicated that no significant difference was detected among the FD values of mesial, distal, and sagittal images at any timepoint. Differences in FD values between the sexes were not significant either.
CONCLUSIONS
Since the FD analysis for the osteogenesis detection of BSMs in maxillary sinus augmentation indicated unstable trends of change, its feasibility is not reliable. The initially rough surface, self-degradation, and volume change of the BSMs during osteogenesis may be the reason for the variation in FD values.
Topics: Humans; Bone Substitutes; Osteogenesis; Pilot Projects; Sinus Floor Augmentation; Fractals; Transverse Sinuses; Minerals; Bone Transplantation; Maxillary Sinus
PubMed: 38157335
DOI: 10.1371/journal.pone.0296248 -
Journal of the Korean Association of... Feb 2023While the reliability of immediate implant placement in the maxillary molar has been discussed, its significance is questionable. There have been no guidelines for case...
OBJECTIVES
While the reliability of immediate implant placement in the maxillary molar has been discussed, its significance is questionable. There have been no guidelines for case selection and surgical technique for successful treatment outcomes of immediate maxillary molar implants. Therefore, in this study, we classified alveolar bone height and socket morphology of the maxillary molar to establish guidelines for immediate implant placement.
MATERIALS AND METHODS
From 2011 to 2019, we retrospectively analyzed 106 patients with 148 immediate implants at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. Inclusion and exclusion criteria were applied, and patient characteristics and treatment results were evaluated clinically and radiologically.
RESULTS
A total of 29 tapered, sand-blasted, large-grit, and acid-etched (SLA) surfaces of implants were placed in 26 patients. The mean patient age was 64.88 years. Two implants failed and were reinstalled, resulting in a 93.10% survival rate. Fluctuating marginal bone level changes indicating bone regeneration and bone loss were observed in the first year following installation and remained stable after one year of prosthesis loading, with an average bone loss of 0.01±0.01 mm on the distal side and 0.03±0.03 mm on the mesial side.
CONCLUSION
This clinical study demonstrated the significance of immediate implant placement in maxillary molars as a reliable treatment with a high survival rate using tapered SLA implants. With an accurate approach to immediate implantation, surgical intervention and treatment time can be reduced, resulting in patient satisfaction and comfort.
PubMed: 36859373
DOI: 10.5125/jkaoms.2023.49.1.30