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Brazilian Oral Research 2023The aim of this study was to evaluate root canal preparation with nickel titanium rotary instruments and complementary preparation with ultrasonic tip in curved canals...
The aim of this study was to evaluate root canal preparation with nickel titanium rotary instruments and complementary preparation with ultrasonic tip in curved canals of mandibular molars with isthmus. Twenty-eight mesial roots of mandibular molars with curvature between 20° and 40° and presence of isthmus throughout the entire extension of the root canals were prepared using ProDesign Logic CM (PDL) up to size 40.05, or HyFlex EDM (HFEDM) up to size 40.04. Complementary preparation was performed in the isthmus region using the ultrasonic insert E18D (Helse, Istmo Diamantada). The root canals were scanned using micro-CT (SkyScan 1176) at 9 µm voxel size before and after each preparation step. Transportation, percentage of increase in volume, debris and uninstrumented surface (UNS) were evaluated. Mann Whitney, Wilcoxon, paired and non-paired t-tests were used for statistical analysis (α = 0.05). The canals prepared with PDL and HFEDM obtained similar results for all the variables assessed before using E18D (p > 0.05). E18D significantly decreased the percentage of debris and UNS values in both Groups (p < 0.05). The complementary preparations with E18D caused a smaller quantity of debris in the isthmus of the canals previously prepared with PDL in comparison with HFEDM (p < 0.05). PDL and HFEDM provided similar root canal preparation. PDL promoted a smaller quantity of Debris in the isthmus than HFEDM after using E18D. E18D significantly improved cleaning, and reduced Debris and UNS.
Topics: Ultrasonics; Dental Pulp Cavity; X-Ray Microtomography; Root Canal Preparation; Titanium; Molar
PubMed: 38055520
DOI: 10.1590/1807-3107bor-2023.vol37.0102 -
Dental Materials Journal Jan 2024Using finite-element analysis, we aimed to determine the center of resistance (CRes) of the maxillary canine for setting orthodontic forces. The inclination of the...
Using finite-element analysis, we aimed to determine the center of resistance (CRes) of the maxillary canine for setting orthodontic forces. The inclination of the canine was measured by first loading from the mesial to the distal side of the mesial root surface, then the position and direction of the load that minimized the inclination were investigated. The CRes was defined as the set of midpoints of the minimum distances between two inclination lines. Twenty-one CRes values were calculated from a set of seven lines. These CRes data were then aggregated as a 95% confidence ellipsoid of width 0.170×0.016×0.009 mm with center points 4.269, 0.224, and 4.315 mm in the apical, mesial, and lingual directions from the origin, respectively. Further studies are required to effectively apply the CRes identified in this study to clinical applications.
Topics: Tooth Movement Techniques; Cuspid; Tooth Root; Finite Element Analysis; Maxilla; Imaging, Three-Dimensional
PubMed: 38044144
DOI: 10.4012/dmj.2023-160 -
International Journal of Implant... Dec 2023To investigate the influence of cantilever prosthetic arm on the marginal bone loss (MBL) over time around dental implants supporting short fixed partial dentures...
PURPOSE
To investigate the influence of cantilever prosthetic arm on the marginal bone loss (MBL) over time around dental implants supporting short fixed partial dentures (FPDs), in a record-based retrospective study.
METHODS
All cases of 3-unit implant-supported FPDs, supported by 2-3 implants, from the database of cases treated at one specialist clinic were considered for inclusion. Only implants with a minimum of 36 months of radiological follow-up were considered. Univariate linear regression models were used to compare MBL over time between 12 clinical covariates, after which a linear mixed-effects model was built.
RESULTS
One-hundred-thirty-nine patients (64 men, 75 women) with 164 3-unit implant-supported FPDs (333 implants supporting non-cantilevered FPDs, 94 supporting cantilevered FPDs) were included in the study. The patients were followed up clinically and radiographically for a mean of 154.1 ± 78.0 (min-max, 37.3-364.6) and 132.9 ± 77.3 months (min-max, 36.8-329.9), respectively. The total number of marginal bone level double measurements (mesial and distal sides of each implant) was 2909. FPDs with cantilever presented an estimated greater MBL over time compared to FPDs without cantilever. Bruxism, sex (women), implant (modified) surface, and (poor) bone quality were also associated with higher MBL over time.
CONCLUSIONS
The use of a cantilever extension is suggested to negatively affect the bone marginal level over time around implants supporting 3-unit FPDs. Due to the small difference of the estimated MBL over long periods of follow-up between the groups, it is a matter of debate if the observed negative effect may be of clinical significance.
Topics: Male; Humans; Female; Retrospective Studies; Dental Implants; Dental Prosthesis Design; Arm; Dental Prosthesis, Implant-Supported; Alveolar Bone Loss; Artificial Limbs
PubMed: 38036796
DOI: 10.1186/s40729-023-00515-w -
Dental Research Journal 2023A successful endodontic treatment requires a comprehensive knowledge of the root canal morphology. This study compared the diagnostic accuracy of cone-beam computed...
BACKGROUND
A successful endodontic treatment requires a comprehensive knowledge of the root canal morphology. This study compared the diagnostic accuracy of cone-beam computed tomography (CBCT) and the sectioning technique for the assessment of mandibular first molar (MFM) root canal morphology.
MATERIALS AND METHODS
In this , experimental study, 48 eligible MFMs were mounted in 12 blocks (groups of 4) made of acrylic resin and sheep bone powder and underwent CBCT. Next, the teeth were mounted in transparent self-cure acrylic blocks, and their roots were sectioned at three points with 3 mm intervals. Images underwent multiplanar reconstruction in NNT Viewer software and were analyzed by one radiologist with the cooperation of an endodontist. The sections were also evaluated by an endodontist under a stereomicroscope (gold standard). The frequency and percentage of single-canal, and two-canal roots were determined by each technique. The agreement between CBCT and the Gold standard was analyzed by calculating the kappa coefficient ( < 0.05).
RESULTS
The diagnostic accuracy of CBCT for the assessment of the MFM root canal morphology was 80% on the mesial surface, 99% in the distal surface, and 96% in total. In the mesial surface, 94.2% of two-canal roots and 66.7% of single-canal roots were correctly detected by CBCT. These values were 100% and 97.4% in the distal surface, and 95.2% and 95.8% in total, respectively. A significant agreement was noted between CBCT and the Gold standard with κ =0.412 for the mesial, 0.939 for the distal, and 0.907 for the total surfaces ( < 0.001).
CONCLUSION
CBCT can be reliably used for the assessment of the complex root canal morphology of MFMs when other modalities fall short.
PubMed: 38020262
DOI: No ID Found -
Medicine and Pharmacy Reports Oct 2023The aim of this study is to quantitatively evaluate the effect of different alcoholic and non alcoholic beverages on the tooth enamel surface topography pretreated with...
A comparative evaluation of the effect of alcoholic and non alcoholic beverages on tooth enamel surface pretreated with β-tricalcium phosphate, bioactive glass and amine fluoride: an study.
BACKGROUND AND AIMS
The aim of this study is to quantitatively evaluate the effect of different alcoholic and non alcoholic beverages on the tooth enamel surface topography pretreated with various remineralizing agents using Atomic Force Microscopy.
METHODS
120 tooth specimens were prepared from 60 freshly extracted intact human premolars by sectioning from mesial to distal surfaces using low speed diamond discs and were randomly assigned to study groups and control group. Specimens of Group I, Group II and Group III were pre-treated with β-Tri calcium phosphate, bioactive glass and amine fluoride respectively for 4 minutes for 28 days, followed by storage in artificial saliva. All the specimens were evaluated for surface roughness using Atomic Force Microscopy. The specimens were then placed in alcoholic and non-alcoholic beverages for 10 minutes for 4 days and were again analyzed by Atomic Force Microscopy.Descriptive statistics was performed by using the proportional or frequency distribution of the parameters. The respondents were then grouped according to the branch of specialty if any and the data was evaluated by the one-way ANOVA with post-hoc, with p value <0.005.
RESULTS
In the present study, among the remineralizing agents tested, bioactive glass was found to be more effective than β-Tri Calcium Phosphate and Amine Fluoride. Among the demineralizing agents used in this study, the demineralization potential of Coca Cola was found to be highest, followed by wine and green tea pretreated with β-tricalcium phosphate, bioactive glass and amine fluoride.
CONCLUSIONS
The present study concluded that all the remineralizing agents tested were found to be effective in inhibiting the demineralization caused by various alcoholic and non alcoholic beverages. Among the remineralizing agents tested, bioactive glass was found to be more effective than β-tri calcium phosphate and amine fluoride.
PubMed: 37970202
DOI: 10.15386/mpr-2465 -
American Journal of Obstetrics &... Dec 2023Agenesis of the corpus callosum is associated with several malformations of cortical development. Recently, features of focal cortical dysgyria have been described in...
BACKGROUND
Agenesis of the corpus callosum is associated with several malformations of cortical development. Recently, features of focal cortical dysgyria have been described in fetuses with agenesis of the corpus callosum.
OBJECTIVE
This study aimed to describe the "cortical invagination sign," a specific sonographic feature of focal cortical dysgyria, which is consistently seen at midtrimester axial brain ultrasound in fetuses with complete agenesis of the corpus callosum.
STUDY DESIGN
This was a retrospective analysis of prospectively collected data from 2018 to 2021, including patients referred to 5 fetal medicine centers in the second trimester of pregnancy (19 0/7 to 22 0/7 weeks of gestation) with suspected complete agenesis of the corpus callosum. All cases with the diagnosis of complete agenesis of the corpus callosum were submitted to an axial sonographic assessment of the fetal brain on the transventricular plane. In this scanning section, the mesial profile of both cerebral hemispheres at the level of the frontal-parietal cortex was investigated. In this area, the operator looked for an abnormal invagination of the cortical surface along the widened interhemispheric fissure, which was referred to as the "cortical invagination sign." All fetuses were submitted to dedicated antenatal magnetic resonance imaging to reassess the ultrasound findings. Cases with additional brain anomalies, which did not involve the cortex, were excluded. The final diagnosis was confirmed at postnatal brain magnetic resonance imaging or postmortem examination, for cases undergoing termination of pregnancy. The primary outcome of this study was to evaluate the presence and laterality of the "cortical invagination sign" in fetuses with complete agenesis of the corpus callosum at antenatal ultrasound and magnetic resonance imaging.
RESULTS
During the study period, 64 cases of complete agenesis of the corpus callosum were included; of those cases, 50 (78.1%) resulted in termination of pregnancy, and 14 (21.9%) resulted in a live birth. The "cortical invagination sign" was detected at ultrasound in 13 of 64 cases (20.3%) and at targeted brain magnetic resonance imaging in 2 additional cases (23.4%), all of which were electively terminated. Moreover, the "cortical invagination sign" was found to be exclusively unilateral and on the left cerebral hemisphere in all the cases. There was a predominant number, although nonsignificant, of male fetuses (80.0% of cases; P=.06) in the group of complete agenesis of the corpus callosum with the "cortical invagination sign."
CONCLUSION
The "cortical invagination sign" is a specific marker of focal cortical dysgyria, which seems to characterize at midtrimester of pregnancy in a large group of fetuses with complete agenesis of the corpus callosum. The etiology, pathophysiology, and prognostic significance of this finding remain to be elucidated.
Topics: Pregnancy; Humans; Male; Female; Corpus Callosum; Pregnancy Trimester, Second; Agenesis of Corpus Callosum; Prenatal Diagnosis; Retrospective Studies; Ultrasonography, Prenatal; Gestational Age; Fetus
PubMed: 37866717
DOI: 10.1016/j.ajogmf.2023.101198 -
Cureus Sep 2023Introduction Oral lichen planus (OLP) and oral lichenoid reaction (OLR) constitute clinical entities with strong but unclear etiologic relation to dental materials. The...
Introduction Oral lichen planus (OLP) and oral lichenoid reaction (OLR) constitute clinical entities with strong but unclear etiologic relation to dental materials. The aim of this study was to evaluate a correlation between the clinical form of OLP/OLR and the number of dental metal restorations in the oral cavity thus utilizing an exposure to metal (EM) index. Material and methods The study type is experimental, and the study design is characterized as semiquantitative research that belongs to the branch of experimental research. Twenty-nine patients were chosen based on clinical (either reticular or erosive clinical forms) and histologic findings suggestive of OLP/OLR. The files of patients were retrieved from the archives of the Department of Oral Medicine/Pathology, School of Dentistry, Aristotle University of Thessaloniki, Greece, during the period 2009-2019. The medical history of the patients did not include any disorder or medication associated with lichenoid lesions and the measurements took place concurrently with the establishment of the diagnosis, thus no treatment for the lichen planus had been administered prior to the measurements. Quantitative measurement of the percentage of dental surfaces restored through metal restorations and correlation with the clinical and histologic findings of OLP/OLR was evaluated. The EM index was evaluated on a scale of 1-3, which corresponds to the percentage of dental surfaces restored through metal restorations. The statistical analysis was performed with the Pearson chi-square test and the significance level was set at ≤0.05. Results The EM index was measured by dividing each tooth into five surfaces (occlusal, mesial, distal, buccal, lingual), subsequently multiplying the number of available teeth with the number 5 to calculate the total number of surfaces, and then counting the number of surfaces with metal restorations - both fillings and crowns (in case of metal-ceramic crowns, the respective dental surface is taken into account only in case of macroscopically exposed metal), dividing the number of surfaces with metal restorations with the total number of surfaces and multiply by 100 so that the results take the form of percentages (%) and finally classifying the percentages into three groups: 1: 0% metal restorations, 2: 1-25% metal restorations, 3: >26% metal restorations). The percentage in female patients ranged from 0% to 100%, whereas it ranged from 0% to 60% in male patients. According to the clinical form of the lichenoid lesion, the percentage ranged from 0% to 60% in reticular lichen planus cases and from 0% to 100% in erosive lichen planus cases. There was no statistical difference between lichen planus cases, in total, and in normal oral epithelium. However, the levels of EM were marginally similar between the reticular lichen planus and the erosive lichen planus (Fisher's exact test, ). Therefore, it may be the case that the EM index is higher in erosive lichenoid lesions. Conclusion In our study, the EM index was higher in female patients and in erosive lichenoid lesions. These findings should be tested and supported by larger samples of patients since the aforementioned Fisher's Exact Test, could fall below the threshold of 0.05 if more patients were included. This is the first attempt to establish a novel approach to differentiating erosive and reticular lichen planus based on the percentage of dental surfaces with metal restorations.
PubMed: 37809260
DOI: 10.7759/cureus.44782 -
Journal of Dental Sciences Oct 2023Denosumab is used to treat bone metastases from malignant tumors. Unlike bisphosphonates, denosumab is not deposited in the bone; thus, withdrawal for a relatively short...
Drug holiday of high-dose denosumab and recovery from osteoclast inhibition using immunohistochemical investigation of 7 patients with medication-related osteonecrosis of the jaw undergoing segmental mandibulectomy.
BACKGROUND/PURPOSE
Denosumab is used to treat bone metastases from malignant tumors. Unlike bisphosphonates, denosumab is not deposited in the bone; thus, withdrawal for a relatively short period would help recovery from osteoclast suppression. This study investigated the relationship between drug holidays and recovery from osteoclast suppression.
MATERIALS AND METHODS
Seven patients who received high-dose denosumab and underwent segmental mandibulectomy for medication-related osteonecrosis of the jaw were enrolled in this study. Osteoclast suppression (+) was defined as the absence of cathepsin K-positive cells or cathepsin K-positive mononuclear or small multinucleated cells observed on the bone surface of both mesial and distal specimens. When normal osteoclasts were found, osteoclast suppression was defined as (-); when both suppressed cathepsin K-positive cells and normal morphological osteoclasts were found, it was defined as (±).
RESULTS
Osteoclast suppression was: (+) in four patients, three without a drug holiday and one with a 9-month drug holiday; (±) in one patient with an 8-month drug holiday, and (-) in two patients with drug holidays for 13 and 20 months.
CONCLUSION
These findings suggest that a long-term drug holiday, such as 12 months, is required for recovery from osteoclast suppression in patients with cancer receiving high-dose denosumab.
PubMed: 37799892
DOI: 10.1016/j.jds.2023.01.021 -
Journal of Dental Sciences Oct 2023Intraoral repair usually takes the convenience of the patient's daily life as the starting point, taking into account the bonding strength, operational feasibility, and...
BACKGROUND/PURPOSE
Intraoral repair usually takes the convenience of the patient's daily life as the starting point, taking into account the bonding strength, operational feasibility, and safety. This study aimed to evaluate the survival of composite resin by simulating cavity fracture repair in porcelain-fused-to-metal (PFM) crowns and referring to the G.V. Black classification of caries as ceramic- and metal-site exposure.
MATERIALS AND METHODS
Mechanical sandblast experimental and a nonsandblast control groups comprised 120 samples, and interfacial locking was enhanced through acid etching, bonding, and light-curing composite resin restoration. Classes of VI buccal (B), III mesial (M), and IV mesiobuccal (MB) types, were investigated. Load tests were performed on two sets, with one set at room temperature for 24 h and the other via thermal cycling at 5 °C/50 °C 720 times. Loading was gradually applied to the samples until a maximum of 450 N was reached.
RESULTS
Results showed that 24 h survival rates of B-, M - , and MB-repaired PFM crowns were 88%, 84%, and 88%, respectively. The repaired PFM survival rates for B, M, and MB were 52%, 44%, and 28%, respectively, after thermal cycling and loading tests. Multiple logistic regression and chi-square test (α = 0.05) showed that the regression results of factors affecting survival assessment were only significant between groups after thermal fatigue ( < 0.05). Survival rate of repairing metal-site in the MB model was significantly higher than that of ceramic-sites repairing in non-blasted samples. For the MB cavity model, sandblasting can significantly improve the survival rate of the repair of ceramic parts in the MB model ( < 0.05).
CONCLUSION
Our results suggest that sandblasting can be further considered, especially for MB cavity fractures when ceramic-site restorations are required.
PubMed: 37799887
DOI: 10.1016/j.jds.2023.01.003 -
Journal of Indian Society of... 2023Rough surfaces of dental implants, when exposed to the oral environment, are conducive to biofilm colonization and can predispose the affected implant to...
Rough surfaces of dental implants, when exposed to the oral environment, are conducive to biofilm colonization and can predispose the affected implant to periimplantitis. Recession coverage using soft-tissue grafts is one of the treatment modalities used for the treatment of exposed implant threads. Recession coverage on the palatal aspect of maxillary implants is difficult due to the firm nature of the palatal mucosa and, consequently has not been widely documented in the literature. This case report documents a novel double-pedicle technique for palatal recession coverage on a dental implant. Two pedicle grafts were obtained from either side of the implant with the mucosal recession: a full-thickness lateral-pedicle graft from the distal aspect and a subepithelial connective tissue pedicle from the mesial aspect. The connective tissue pedicle was stabilized first on the area of mucosal recession and was then covered with the distal full-thickness lateral pedicle. Complete recession coverage was obtained, and the result was observed to be clinically stable after 18 months of follow-up. The technique demonstrated in this report can be a useful tool for the treatment of localized palatal recessions on dental implants.
PubMed: 37781328
DOI: 10.4103/jisp.jisp_379_22