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Epilepsia Jun 2012To date, magnetic resonance imaging (MRI)-based studies of the cerebral cortex in mesial temporal lobe epilepsy (MTLE) have focused primarily on investigating cortical...
PURPOSE
To date, magnetic resonance imaging (MRI)-based studies of the cerebral cortex in mesial temporal lobe epilepsy (MTLE) have focused primarily on investigating cortical volume and thickness. However, volume is a composite of surface area and thickness, each reflecting distinct neurobiologic and genetic processes. The goal of this study was to investigate cerebral cortex (1) surface area, (2) surface geometric distortion, and (3) thickness in MTLE with hippocampal sclerosis (HS).
METHODS
Seventy patients with "sporadic" unilateral MTLE + HS and 40 healthy controls underwent T(1) -weighted MRI. Processing MR images using an automated cortical surface reconstruction method (FreeSurfer), we quantified cortical surface area, surface geometric distortion (metric distortion), and thickness at each vertex across the entire cortex. Differences between patients and controls were determined using generalized linear models. Separate linear regression models were employed to assess the relationship between cortical surface area and hippocampal volume as well as a series of important clinical features of the condition.
KEY FINDINGS
We detected an asymmetric reduction in cortical surface area, predominantly in ipsilateral mesial and anterior temporal lobe subregions, of patients with MTLE + HS. Changes in surface geometric features were also evident and closely mirrored surface area patterns. In contrast, cortical thinning appeared dispersed across the cortex bilaterally. The regression models revealed that ipsilateral hippocampal volume was a significant predictor of temporal lobe surface area changes.
SIGNIFICANCE
Our findings indicate that contraction in surface area, rather than cortical thinning, explains ipsilateral mesial and anterior temporal lobe atrophy in patients with MTLE with HS. Furthermore, the alterations in surface geometry indicate folding abnormality involving the same regions. Cortical surface changes may represent sequelae of the disease or deviant cortical development.
Topics: Adult; Brain Mapping; Cerebral Cortex; Electroencephalography; Epilepsy, Temporal Lobe; Female; Functional Laterality; Hippocampus; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Middle Aged; Sclerosis; Statistics, Nonparametric
PubMed: 22510097
DOI: 10.1111/j.1528-1167.2012.03457.x -
The Angle Orthodontist Jan 2022To compare deep overbite treatment using 0.016 × 0.022 nickel-titanium lower reverse curve of Spee archwire (LRCA) or metal anterior bite turbos (ABTs). (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
To compare deep overbite treatment using 0.016 × 0.022 nickel-titanium lower reverse curve of Spee archwire (LRCA) or metal anterior bite turbos (ABTs).
MATERIALS AND METHODS
48 patients with deep overbite malocclusion were randomly allocated into two groups. Group I (age = 18.4 ± 2.8 years, overbite = 5.8 ± 0.6 mm) was treated with LRCA, while Group II (age = 18.2 ± 3.1 years, overbite = 5.2 ± 0.4 mm) was treated with ABTs bonded to the palatal surface of the upper central incisors. Two cephalograms were taken for each patient, at post-alignment stage (T1) and post-leveling stage (T2). The primary outcomes were the anteroposterior and vertical changes of the lower teeth. The secondary outcomes were the effect on upper incisor inclination and the vertical linear changes of upper teeth, to assess the sagittal and vertical skeletal changes, and to compare the duration of overbite correction.
RESULTS
42 of the 48 patients recruited completed the study (21 in each group). At T2, the lower incisors proclined more in Group I (P ≤ .001). Both lower second molars (P ≤ .001) and lower first molars (P = .001) tipped more distally, while the lower first premolar tipped more mesially, in Group I (P < .05). All cusps of both lower molars showed more extrusion in Group II (P < .05) except for the mesial cusp of lower second molars (P = .095). The duration of overbite correction was shorter using the ABTs by 1.7 months (4.85 ± 1.56 and 3.15 ± 0.93 months for Group I and Group II, respectively).
CONCLUSIONS
LRCA causes lower incisor proclination with distal tipping of lower molars, while ABTs result in lower posterior tooth extrusion.
Topics: Adolescent; Adult; Cephalometry; Humans; Incisor; Malocclusion, Angle Class II; Mandible; Overbite; Tooth Movement Techniques; Young Adult
PubMed: 34329389
DOI: 10.2319/020921-117.1 -
BMC Oral Health Jun 2023This 18-month randomized clinical trial aimed to compare the effectiveness of two topical fluoride applications versus placebo control on preventing development of... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
This 18-month randomized clinical trial aimed to compare the effectiveness of two topical fluoride applications versus placebo control on preventing development of approximal caries in primary teeth.
METHODS
Preschool children were recruited if they had at least one initial approximal carious lesion at the distal surface of the canines, both approximal surfaces of the first molars, or the mesial surface of the second molars assessed from bitewing radiographs. The participants were randomly allocated into 3 intervention groups: Group 1 (placebo control), Group 2 (5% sodium fluoride [NaF] varnish), and Group 3 (38% silver diamine fluoride [SDF]). All agents were applied semiannually. Two calibrated examiners evaluated the caries development from bitewing radiographs. Caries development was recorded when the baseline sound surface or initial approximal carious lesion surface developed dentin caries (beyond the outer one-third of dentine) at the follow-up examination. The intention-to-treat approach was adopted. The Chi-square test was used to analyze the effectiveness of topical fluoride agents in preventing approximal caries development and the effect of other variables. The multi-level logistic regression analysis was performed to assess the relative effectiveness of topical fluoride agents in preventing approximal caries development at the 18-month follow-up.
RESULTS
At baseline, 190 participants with 2,685 sound or initial carries at the approximal surfaces were recruited. No differences in participant demographic backgrounds, oral health related habits, or caries experience were observed among the 3 groups (P > 0.05). After 18 months, 155 (82%) participants remained in the study. The rates of developing approximal caries in Groups 1, 2, and 3 were 24.1%, 17.1%, and 27.2%, respectively (P < 0.001, χ test). After adjusting for confounding factors and clustering effect, the multilevel logistic regression analysis showed no differences in caries development rates between the 3 groups (P > 0.05). Tooth type and the extent of a carious lesion at baseline were the significant factors for caries development.
CONCLUSION
At 18-month follow-up, after adjusting for confounding factors and clustering effect, there were no statistically significant differences in preventing of approximal caries development between the semiannual application of 5%NaF, 38%SDF, or placebo.
TRIAL REGISTRATION
The study was registered in the Thai Clinical Trials Registry under the number TCTR20190315003 on 15/03/2019.
Topics: Humans; Fluorides; Fluorides, Topical; Cariostatic Agents; Dental Caries Susceptibility; Dental Caries; Sodium Fluoride; Tooth, Deciduous
PubMed: 37268914
DOI: 10.1186/s12903-023-03045-4 -
International Journal of Paediatric... Nov 2020The mesial surface of the first permanent molar is the most caries-susceptible proximal surface of the permanent dentition in children under the age of 12.
BACKGROUND
The mesial surface of the first permanent molar is the most caries-susceptible proximal surface of the permanent dentition in children under the age of 12.
AIM
The aim of this study was to determine the association between caries progression on the mesial surface of the first permanent molar (T6M) and caries on the distal surface of the primary second molar (t5D) and the occlusal surface of the first permanent molar (T6O).
DESIGN
Children (between 5 and 13 years old; N = 565) that had participated in a 4-year longitudinal caries study that at baseline had at least one T6 fully erupted with a t5 in proximal contact, with no restoration or sealant on T6O and t5D, and adequate bitewing radiographs were included. Clinical data using the International Caries Detection and Assessment System (ICDAS) and radiographs were used to determine the caries status of T6M, T6O, and t5D.
RESULTS
Baseline caries presence on t5D and T6O were highly significantly associated with follow-up caries presence on T6M (P < .001). The adjusted odds ratios corresponding to t5D and T6O were 3.94 (95% CI: [1.78, 8.71]) and 3.26 (95% CI: [1.46, 7.31]), respectively.
CONCLUSION
These findings highlight the need for prevention and management of caries on T6O and t5D.
Topics: Adolescent; Child; Child, Preschool; Dental Caries; Dentition, Permanent; Disease Progression; Humans; Molar; Tooth, Deciduous
PubMed: 32275104
DOI: 10.1111/ipd.12650 -
Progress in Orthodontics 2016An important constituent of an orthodontic appliance is orthodontic brackets. It is either the bracket or the archwire that slides through the bracket slot, during...
BACKGROUND
An important constituent of an orthodontic appliance is orthodontic brackets. It is either the bracket or the archwire that slides through the bracket slot, during sliding mechanics. Overcoming the friction between the two surfaces demands an important consideration in an appliance design. The present study investigated the surface roughness of four different commercially available stainless steel brackets.
METHODS
All tests were carried out to analyse quantitatively the morphological surface of the bracket slot floor with the help of scanning electron microscope (SEM) machine and to qualitatively analyse the average surface roughness (Sa) of the bracket slot floor with the help of a three-dimensional (3D) non-contact optical surface profilometer machine.
RESULTS
The SEM microphotographs were evaluated with the help of visual analogue scale, the surface roughness for group A = 0-very rough surface, group C = 1--rough surface, group B = 2--smooth surface, and group D = 3-very smooth surface. Surface roughness evaluation with the 3D non-contact optical surface profilometer machine was highest for group A, followed by group C, group B and group D. Groups B and D provided smooth surface roughness; however, group D had the very smooth surface with values 0.74 and 0.75 for mesial and distal slots, respectively.
CONCLUSIONS
Evaluation of surface roughness of the bracket slot floor with both SEM and profilometer machine led to the conclusion that the average surface roughness was highest for group A, followed by group C, group B and group D.
Topics: Friction; Imaging, Three-Dimensional; Materials Testing; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Stainless Steel; Surface Properties
PubMed: 26763529
DOI: 10.1186/s40510-016-0116-2 -
Journal of Healthcare Engineering 2020The aim of this in vitro study was to measure the temperature increases produced on the mesial and vestibular root surfaces of premolar teeth during a laser-softened...
The aim of this in vitro study was to measure the temperature increases produced on the mesial and vestibular root surfaces of premolar teeth during a laser-softened gutta-percha obturation technique. We studied 12 extracted human premolar teeth with a single canal. After root canal cleaning and shaping, the teeth were obturated with gutta-percha that had been softened with a neodymium-doped yttrium aluminium garnet (Nd:YAG) laser (CTL 1503) at a wavelength of 1.064 nm. The laser setup parameters included a 30 Hz frequency and a 200 mJ/pulse with optical fiber tips of 0.320 mm diameter. A sectional warm gutta-percha condensation was used. Temperature changes on the whole mesial and vestibular outer surfaces of the roots were measured at approximately 2 s intervals with an infrared thermal imaging camera. A significantly higher increase in temperature was observed for the mesial root surface (7.5°C) compared to the vestibular surface (3.7°C) ( ≈ 0). The findings suggested that root canal filling with Nd:YAG laser-softened gutta-percha in premolar teeth is not likely to damage the surrounding periradicular tissues. To obtain valid temperature results, the measurement should be performed on the surface with the thinnest root wall.
Topics: Gutta-Percha; Hot Temperature; Humans; In Vitro Techniques; Lasers, Solid-State; Neodymium; Root Canal Obturation
PubMed: 32587668
DOI: 10.1155/2020/8828272 -
Caries Research 2000The aim was to analyse the pattern of caries rates in enamel and dentin of the mesial surface of the first permanent molar (mesial 16, 26,36,46; here called 6m) and the... (Comparative Study)
Comparative Study
The aim was to analyse the pattern of caries rates in enamel and dentin of the mesial surface of the first permanent molar (mesial 16, 26,36,46; here called 6m) and the distal surface of the second primary molar (distal 55,65,75,85; here called 05d) from 6 to 12 years of age. The material consisted of retrospectively collected bite-wing radiographs of a cohort of 374 children aged 5-7 years at baseline and followed to 11-12 years of age. The following scoring system was used: score 0 = no visible radiolucency, 1-2 = radiolucency in the outer (1) or inner (2) half of the enamel up to the enamel-dentin border, 4 = radiolucency with obvious spread in the outer half of the dentin, and 5 = radiolucency in the inner half of the dentin. Two transitions were used: state 0-2 = the time lapse from state 0 until the lesion had reached state 2, and state 2-4 = the time lapse from state 2 until the lesion had reached state 4 or 5. At the age of 9, the mean defs (decayed, extracted and filled surfaces) of 05d was 0.70 and the mean DFS of 6m was 0.19. The enamel caries rates (state 0-2) were 4.6 new lesions/100 tooth surface-years for 6m and 11.3 for 05d. The dentin caries rates (state 2-4) were 20.5 new lesions/100 tooth surface-years for 6m and 32.6 for 05d. In conclusion, the enamel caries rate for 05d was more than twice that for 6m. Both surfaces had relatively high dentin caries rates, indicating that for these surfaces between 6 and 12 years of age, the rate of progression into the dentin is generally relatively high once the lesion has reached the inner half of the enamel as judged radiographically.
Topics: Age Factors; Child; Child, Preschool; Cohort Studies; Confidence Intervals; DMF Index; Dental Caries; Dental Caries Susceptibility; Dental Enamel; Dentin; Disease Progression; Female; Follow-Up Studies; Humans; Male; Molar; Radiography, Bitewing; Retrospective Studies; Sex Factors; Sweden; Tooth, Deciduous
PubMed: 11093018
DOI: 10.1159/000016623 -
Journal of Clinical Periodontology Nov 1990Cementum thickness increases uniformly with age, and questionably from functional stimulation due to tensional forces. Mesial drift of teeth results in tensional forces...
Cementum thickness increases uniformly with age, and questionably from functional stimulation due to tensional forces. Mesial drift of teeth results in tensional forces on distal root surfaces. This study evaluated whether there was any discernible effect on cementum thickness related to mesial drift in humans. The material consisted of maxillary and mandibular bicuspids and molars with their surrounding periodontia from 5 humans (mean age at death, 48.6 years). The teeth and tissues had been sectioned histologically in a mesio-distal plane, and the analysis for each tooth was done using 3 step-serial sections from the mid-buccolingual region. On the mesial and distal surface of each tooth, cementum thickness was measured in microns at 3 defined locations at a level representing the mid-point of root length for bicuspids and molars. Means from the measurements on mesial and distal surfaces were compared using descriptive and and inferential statistical methods. For each individual tooth analyzed, the cementum was thicker on the distal surface (range greater, 32-107%; mean, 69%). The statistical comparisons showed that cementum thickness on the distal surface was significantly greater for bicuspids (mesial, 135 microns: distal, 216 microns), molars (mesial, 154 microns: distal, 284 microns), and all teeth combined (mesial, 154 microns: distal, 284 microns). The magnitude of this difference became greater with increasing age. It was concluded that cementum thickness was markedly greater on the distal surfaces of teeth from adult humans, and that this may be due to functional stimulation from mesial drift over time.
Topics: Adult; Aging; Dental Cementum; Dental Enamel; Female; Humans; Male; Mesial Movement of Teeth; Middle Aged; Odontometry; Periodontal Ligament; Periodontitis; Tooth Root
PubMed: 2262584
DOI: 10.1111/j.1600-051x.1990.tb01058.x -
Journal of Periodontology Nov 1985Treating periodontitis which involves the mesial concavity of the maxillary first bicuspid can be very challenging. Fifty extracted adolescent maxillary first bicuspids...
Treating periodontitis which involves the mesial concavity of the maxillary first bicuspid can be very challenging. Fifty extracted adolescent maxillary first bicuspids were sectioned in 2-mm thick sections apical to the cementoenamel junction (CEJ). The mesial concavity depth and the cementum and dentin thickness were measured in the sections. The single-rooted bicuspids have a concavity 0.35 mm deep at the CEJ and a concavity 0.59 mm deep 4.7 mm apical to the CEJ. Two-rooted bicuspids furcate at 7.9 mm and have a concavity 0.44 mm deep at the CEJ which increases to 1.08 mm at the 4.7 mm level. Cementum thickness averages from 0.9 mm at the CEJ to 1.1 mm at the 9.4-mm level. Most bicuspids also have a distal concavity which is deepest at the 4.7-mm level. The results imply that any attachment loss around the maxillary first bicuspid involves surfaces which are most likely concave. These concave surfaces make both plaque removal and various periodontal therapeutic procedures difficult.
Topics: Adolescent; Bicuspid; Child; Dental Cementum; Dental Enamel; Humans; Maxilla; Tooth Root
PubMed: 3863916
DOI: 10.1902/jop.1985.56.11.666 -
Compendium of Continuing Education in... Mar 2019The use of silver diamine fluoride (SDF) for management of dental caries has gained considerable attention due to recent regulatory clearance in the United States. The... (Review)
Review
The use of silver diamine fluoride (SDF) for management of dental caries has gained considerable attention due to recent regulatory clearance in the United States. The primary focus of policies, presentations, and publications has been the arrest of caries lesions (cavities) because of the material's unique ability to non-invasively achieve this elusive and clinically important goal. However, SDF also has proven efficacy in prevention, ie, decreasing the incidence of new caries lesions. Analysis of nine clinical trials in children shows that SDF prevented 61% of new lesions compared to controls. To prevent one new caries lesion, clinicians need to treat four primary teeth (one patient) or 12.1 permanent molars (three patients) with SDF. The preventive effect appears to be immediate and maintains at the same fraction over time. Direct comparisons of SDF applied once per year with alternative treatments show that SDF is more effective than other topical fluorides placed two to four times per year and more cost-effective than dental sealants. Enamel lesions may be even more responsive than cavitated dentin lesions. Annual application of SDF to high-risk surfaces (eg, mesial surfaces of permanent first molars where the distal surface of the second primary molar is carious) in patients with any risk of new caries lesions appears to be the most cost-effective approach available to prevent dental caries. SDF is an underutilized evidence-based preventive agent for dental caries.
Topics: Child; Cost-Benefit Analysis; Dental Caries; Fluorides, Topical; History, 20th Century; Humans; Quaternary Ammonium Compounds; Silver Compounds
PubMed: 30829497
DOI: No ID Found