Background: The purpose of this study was to evaluate the effect of the amount of periodontal support on the fracture resistance of root-amputated maxillary molar teeth restored with either direct class. I. restorations or class II. mesio-occluso-distal (MOD) indirect overlay restorations with cuspal coverage.
Methods: Sixty sound maxillary first molars were collected and randomly divided into four groups. In Groups 1 and 2, MOD cavities were prepared and all cusps were reduced by 2 mm, whereas in Group 3 and 4, only a conservative Class I. cavity was prepared. Subsequently, root canal treatment was performed and the mesio-buccal roots were amputated. Groups 1 and 2 were restored with indirect composite overlay, while Groups 3 and 4 received direct composite fillings. After restoration, teeth were embedded as follows: Groups 1 and 3: normal bone level, Groups 2 and 4: furcation involvement. The specimens were submitted to static fracture resistance testing. Fracture thresholds and fracture patterns were measured and evaluated.
Results: Group 1 had the highest fracture resistance (2311,6 N) among the restored groups and showed statistically significant difference compared to Group 2 (p = 0.038) and Group 4 (p = 0.011). There was no statistically significant difference in terms of fracture resistance between the rest of the groups. In terms of the fracture patterns, Group 3 was characterized by the highest percentage (60%) of mostly favorable fractures, while the rest of the groups showed predominantly unfavorable ones.
Conclusions: The amount of periodontal support seems to influence the fracture resistance of root-amputated and restored maxillary molars.
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http://dx.doi.org/10.1186/s12903-019-0958-3 | DOI Listing |
Environ Monit Assess
January 2025
Department of Chemistry, Vaal University of Technology, Vanderbijlpark, South Africa.
Due to incessant contamination of the groundwater system near the dumpsite in southwestern Nigeria Basement Complex, this study seeks to evaluate the impact of the Odogbo dumpsite on the local groundwater system by integrating geophysical and geochemical methodologies. Aeromagnetic data covering the study area was acquired, processed, and enhanced to delineate basement features that could potentially be passing plumes to the groundwater system. Concurrently, geoelectric methods using 2-D dipole-dipole imaging and vertical electrical sounding (VES) were utilized to characterize the vulnerability indices of the lithologies underlying the dumpsite.
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Department of Orthopaedics, Sahlgrenska University Hospital, Gothenburg, Sweden.
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Department of Oculoplastic, Orbital & Lacrimal Surgery, Aichi Medical University Hospital, 1-1 Yazako-Karimata, Nagakute, Aichi, 480-1195, Japan.
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Can Vet J
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Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, 1352 Boyd Avenue, St. Paul, Minnesota 55108, USA.
A 6-year-old Labrador retriever dog with a history of pneumonia was presented because of an acute onset of dull mentation and coughing. Diagnostic imaging and cytology revealed a pneumothorax, pneumomediastinum, and pleural effusion, consistent with pyothorax. The dog underwent exploratory sternotomy for lung lobectomy of the right cranial and middle lung lobes.
View Article and Find Full Text PDFAdv Mater
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Key Laboratory of Advanced Materials Technologies, International (HongKong Macao and Taiwan) Joint Laboratory on Advanced Materials Technologies, College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, China.
Hydrogels have received great attention due to their molecular designability and wide application range. However, they are prone to freeze at low temperatures due to the existence of mass water molecules, which can damage their flexibility and transparency, greatly limiting their use in cold environments. Although adding cryoprotectants can reduce the freezing point of hydrogels, it may also deteriorate the mechanical properties and face the risk of cryoprotectant leakage.
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