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Dental Materials : Official Publication... Jan 2024To evaluate the effect of mono and multi-wave light-curing units (LCUs) on the Knoop hardness of resin-based composites (RBC) that use different photoinitiators.
OBJECTIVES
To evaluate the effect of mono and multi-wave light-curing units (LCUs) on the Knoop hardness of resin-based composites (RBC) that use different photoinitiators.
METHODS
Central incisor-shaped specimens 12 mm long, 9 mm wide, and 1.5 mm thick were made from 2 RBCs that use different photoinitiators: Tetric N-Ceram (Ivoclar Vivadent) - and Vittra APS (FGM), both A2E shade. They were light-cured with 4 different LCUs: two claimed to be multi-wave - VALO Grand (Ultradent) and Emitter Now Duo (Schuster); and two were monowave - Radii Xpert (SDI) and Elipar DeepCure-L (3 M Oral Care) using 2 different light exposure protocols: one 40 s exposure centered over the specimen; and two 20 s light exposures that delivered light from two positions to better cover the entire tooth. 16 groups with 10 specimens in each group were made. The Knoop hardness (KH, kg/mm) was measured at the top and bottom of the specimen in the center and at the cervical, incisal, mesial, and distal peripheral regions. The active tip diameters (mm) and spectral radiant powers (mW/nm) of the LCUs were measured with and without the interposition of the RBC, as well as the radiant exposure beam profiles (J/cm²) delivered to the top of the RBCs. The data was analyzed using Three-way ANOVA and Tukey's tests (α = 0.05).
RESULTS
The VALO Grand (1029 mW) emitted twice the power of the Radii Xpert (500 mW). The KH values of VI and TN resin composite specimens were significantly affected by the LCU used (p < .001), the measurement location (p < .001), and the surface of the specimen (p < .001). LCUs with wider tip diameters produced greater Knoop hardness values at the peripheries of the 12 mm of long, 9 mm wide specimens. In general, the VALO Grand produced the highest KH values, followed by Elipar DeepCure-L, then by Radii Xpert. The Emitter Now Duo LCU produced the lowest values. Exposing the veneers from two locations reduced the differences between the LCUs and the effect of the measurement location. Only the VALO Grand could fully cover the composite veneer with light when the two locations were used.
SIGNIFICANCE
The light tip must cover the entire restoration to photocure the RBC beneath the light tip.
Topics: Hardness; Curing Lights, Dental; Light-Curing of Dental Adhesives; Materials Testing; Composite Resins; Dental Materials; Polymerization
PubMed: 37919111
DOI: 10.1016/j.dental.2023.10.019 -
Journal of Dentistry Dec 2023The study represents a preliminary evaluation of the accuracy of the dynamic navigation system (DNS) in coronectomy of the mandibular third molar (M3M).
OBJECTIVES
The study represents a preliminary evaluation of the accuracy of the dynamic navigation system (DNS) in coronectomy of the mandibular third molar (M3M).
METHODS
The study included participants with an impacted M3M near the inferior alveolar canal. The coronectomy planes were designed before the surgery using cone-beam computed tomography (CBCT) imaging data and then loaded into the DNS program. Intraoperatively, the navigation system was used to guide the complete removal of the target crown. Postoperative CBCT imaging was used to assess any three-dimensional deviations of the actual postoperative from the planned preoperative section planes for each patient.
RESULTS
A total of 12 patients (13 teeth) were included. The root mean square (RMS) deviation of the preoperatively designed plane from the actual postoperative surface was 0.69 ± 0.21 mm, with a maximum of 1.45 ± 0.83/-1.87 ± 0.63 mm deviation. The areas with distance deviations < 1 mm, 1-2 mm, and 2-3 mm were 71.97 ± 5.72 %, 22.96 ± 6.57 %, and 4.52 ± 2.28 %, respectively. Most patients showed extremely high convexity of the surface area located in the mesial region adjacent to the base of the extraction socket. There was no observable evidence of scratching of the buccolingual bone plate at the base of the extraction socket by the handpiece drill.
CONCLUSIONS
These results provide preliminary support for the use of DNS-based techniques when extracting M3M using a buccal approach. This would improve the accuracy of coronectomy and reduce the potiential damage to the surrounding tissue.
CLINICAL SIGNIFICANCE
DNS is effective for guiding coronectomy.
Topics: Humans; Molar, Third; Pilot Projects; Tooth Extraction; Trigeminal Nerve Injuries; Mandible; Cone-Beam Computed Tomography; Computers; Mandibular Nerve
PubMed: 37898432
DOI: 10.1016/j.jdent.2023.104762 -
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 -
The International Journal of Oral &... Oct 2023To evaluate the bone level changes in a new implant design (fully tapered with platform switching) with the one-abutment one-time protocol after 1 year of loading.
PURPOSE
To evaluate the bone level changes in a new implant design (fully tapered with platform switching) with the one-abutment one-time protocol after 1 year of loading.
MATERIALS AND METHODS
Thirty patients received 1 or 2 implants (6-, 8-, or 10-mm length and 3.5-, 3.75-, or 4.5-mm diameter, bone-level design) to replace one or multiple edentulous sites. Only the mesial implant was assessed. Radiographic, clinical, and esthetic results and the survival and success rates were evaluated 1 year after final loading.
RESULTS
At 1 year, no peri-implant bone loss was seen in any of the cases. Mean marginal crestal bone loss between surgery and crown placement was 0.19 ± 0.17 mm (P < .0001). Between surgery and the 1-year follow-up, the mean marginal crestal bone loss was 0.25 ± 0.24 mm (P < .0001). The difference in the modified Plaque Index between 1 year of follow-up and crown placement was significant for in the mesial (0.33 ± 0.54 mm; P = .003) and distal surfaces (0.5 ± 0.73 mm; P = .001). The probing pocket depth was statistically significantly deeper at 1 year than at crown placement at the mesial and distal aspects (average depth = 0.75 mm; P < .0005). No statistically significant differences were found for any other clinical or esthetic parameters. The overall survival and success rates after 1 year were 100%.
CONCLUSIONS
The fully tapered, deep-thread, platform-switched implant design placed with the one-abutment one-time protocol demonstrated minimal marginal crestal bone loss and crestal bone stability at 1 year of follow-up.
Topics: Humans; Alveolar Bone Loss; Dental Implantation, Endosseous; Dental Implants; Esthetics, Dental; Follow-Up Studies; Mouth, Edentulous; Dental Abutments
PubMed: 37847836
DOI: 10.11607/jomi.10276 -
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 -
Journal of Indian Society of... 2023Periodontitis is the most common type of periodontal condition, primarily affecting middle-aged people and resulting in tooth loss; when combined with diabetes, it...
A pilot study on the comparative evaluation of residual periodontal ligament in extracted teeth of chronic periodontitis patients with and without type 2 diabetes - Vital function of an occult dimension.
BACKGROUND
Periodontitis is the most common type of periodontal condition, primarily affecting middle-aged people and resulting in tooth loss; when combined with diabetes, it becomes a debilitating condition. The aim of this study is to compare the residual periodontal ligament length in periodontitis patients with and without diabetes.
MATERIALS AND METHODS
The cross-sectional observational study was conducted in the department of periodontics over 5 months. The patients in the study were divided into two groups. Group 1 comprised patients with periodontitis without type 2 diabetes and Group 2 comprised patients with periodontitis with type 2 diabetes. A total of 100 teeth 50 from each group were collected. The teeth were stained, and the Residual Periodontal Ligament (RPL) of all tooth aspects and surfaces to a total of 544 were measured. Two points were identified for measuring the RPL. The first point was from the apex of the tooth and the second point was the highest marking of the stain. The length from these two points was recorded as the RPL. Following which, means from Groups 1 and 2 were calculated to determine the rate of destruction. The average of the values for each tooth was calculated to determine the percentage of RPL in each tooth and surface. The Mann-Whitney test was used to compare the RPL of the teeth surfaces and Group 1 and Group 2 and < 0.05 was considered statistically significant.
RESULTS
The RPL was higher in nondiabetic patients, with a mean value of 23.66 mm, when compared to diabetic patients, with a mean RPL of 17.05 mm, implying that diabetic patients showed greater periodontal destruction. Buccal tooth surfaces displayed a mean RPL of 4.24 mm and 6.00 mm, lingual/palatal tooth surfaces with 4.02 mm and 5.91 mm, mesial tooth surfaces with 3.82 mm and 5.64 mm, and distal tooth surfaces showed 4.14 mm and 5.67 mm (diabetic and nondiabetic, respectively) with ( < 0.001) found to be statistically significant.
CONCLUSION
This study observed that the destruction rate of the periodontal ligament was higher in diabetic teeth than in nondiabetic teeth, implying that patients with metabolic diseases such as type 2 diabetes influence the response of periodontal tissues to periodontitis and that hyperglycemia impacts the periodontal ligament either directly or indirectly.
PubMed: 37781325
DOI: 10.4103/jisp.jisp_522_22 -
Heliyon Oct 2023It is common for dental technicians to adjust the proximal surface of adjacent teeth on casts when fabricating single crowns. However, whether the accuracy of the...
BACKGROUND
It is common for dental technicians to adjust the proximal surface of adjacent teeth on casts when fabricating single crowns. However, whether the accuracy of the proximal contact is affected if this step is eliminated is unclear.
OBJECTIVE
To evaluate the accuracy of the proximal contact of single crowns for mandibular first molars fabricated from four different restorative materials, without adjustment of the proximal surface of the adjacent teeth by the laboratory/dental technician.
METHODS
This study was in vitro; all the clinical procedures were conducted on a dentoform. The mandibular first molar tooth on the dentoform was prepared using diamond burs and a high speed handpiece. Twenty single crowns were fabricated, five for each group (monolithic zirconia, lithium disilicate, metal ceramic, and cast gold). No proximal surface adjacent to the definitive crowns was adjusted for tight contact in the dental laboratory. Both the qualitative analyses, using dental floss and shimstock, and the quantitative analyses, using a stereo microscope, were performed to evaluate the accuracy of the proximal contact of the restoration with the adjacent teeth. In the quantitative analysis, one-way analysis of variance was used to compare mean values at a significance level of 0.05.
RESULTS
In quantitative analysis, the differences between the proximal contact tightness of the four groups was not statistically significant ( = 0.802 for mesial contacts, = 0.354 for distal contacts). In qualitative analysis, in most crowns, dental floss passed through the contact with tight resistance and only one film of shimstock could be inserted between the adjacent teeth and the restoration. However, one specimen from the cast gold crown had open contact.
CONCLUSIONS
Even without proximal surface adjustment of the adjacent teeth during the crown fabrication process, adequate proximal contact tightness between the restoration and adjacent teeth could be achieved.
PubMed: 37767497
DOI: 10.1016/j.heliyon.2023.e20403