Purpose: The aim of this study was to investigate the effect of offsetting the middle or peripheral implant on the compressive stress values in the crestal bone around the neck of the dental implant.
Materials And Methods: Three finite element models describing three titanium implants installed in quadrilateral pieces of bone was executed. A 2-mm nickel chromium superstructure representing a bridge was modeled over the implant abutments. In model 1, implants were installed along a straight line. Model 2 had the middle implant installed outside the line connecting the two peripheral implants buccally. Model 3 had the mesial implant installed out of alignment. Six 100-N loads were modeled on top of the mesial and middle implants of the three models individually. Loads 1 and 2 were directed vertically on the mesial and middle implants, while loads 3 and 4 represented the horizontal loads in the buccal direction. Loads 5 and 6 were directed mesially on the mesial and central implants. Maximal compressive stress levels in the crestal bone of the three models were then investigated.
Results: The results demonstrated that offset implant installation revealed slightly lower bone stresses under buccally or lingually directed horizontal forces. Slightly higher bone stresses under vertical loads were observed. Horizontal mesial or distal loads resulted in slightly higher bone stresses than those caused by buccal or lingual loading.
Conclusions: The in-line implant alignment clearly had the safest compressive stress outcome on the surrounding structure under vertical loads. Under buccolingual loads, implant alignment with peripheral offset would have, relatively, the safest compressive stress outcome on bone.
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http://dx.doi.org/10.1111/j.1708-8208.2007.00055.x | DOI Listing |
Resilience to stressors has emerged as a major gerontological concept aiming to promote more positive outcomes for older adults. Achieving this aim relies on determining mechanisms underlying capacity to respond resiliently. This paper seeks proof of principle for the hypothesis that physical aspects of said capacity are rooted in the fitness of one's physiology governing stress response, conceptualized as a dynamical system.
View Article and Find Full Text PDFOper Dent
January 2025
Nathaniel C Lawson, DDS, PhD, director of Master of Science in Dental Biomaterials program and associate professor, Department of Clinical and Community Sciences, University of Alabama at Birmingham School of Dentistry, Birmingham, AL, USA.
Objective: This study aimed to assess the fracture resistance of chairside computer assisted design and computer assisted manufacturing (CAD-CAM) lithium disilicate partial and full-coverage crowns and veneers for maxillary canines.
Methods And Materials: Forty-eight restorations for maxillary right canines (12 per group) were designed as follows: (1) partial crown with finish line in the upper middle third; (2) partial crown with finish line in the lower middle third; (3) traditional labial veneer; and (4) traditional full-coverage crown. Restorations were fabricated out of lithium disilicate (Amber Mill, Hassbio) using a chairside CAD-CAM system (Cerec Dentsply Sirona).
BMC Oral Health
January 2025
Department of Stomatology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510080, China.
Background: Proper torque control is crucial to the outcome of orthodontic treatment. This study aimed to employ finite element analysis to compare the torque capabilities of a novel spherical self-ligating bracket with a lock-hook system against those of commonly used passive self-ligating and conventional bracket systems, as well as to reveal the biomechanical changes in the periodontal ligament (PDL) during torque expression.
Methods: A maxillary right central incisor, along with its PDL and alveolar bone, were modeled.
Glia
January 2025
Kentucky Spinal Cord Injury Research Center, University of Louisville, School of Medicine, Louisville, Kentucky, USA.
Cellular stressors inhibit general protein synthesis while upregulating stress response transcripts and/or proteins. Phosphorylation of the translation factor eIF2α by one of the several stress-activated kinases is a trigger for such signaling, known as the integrated stress response (ISR). The ISR regulates cell survival and function under stress.
View Article and Find Full Text PDFHeliyon
December 2024
Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China.
Knee Osteoarthritis (KOA) is characterized by phenotypic alterations, apoptosis, and the breakdown of the extracellular matrix (ECM) in the superficial articular cartilage cells. The inflammatory response activates the Endoplasmic Reticulum Stress (ERS) signaling pathway, which plays a critical role in the pathophysiology and progression of KOA. Chondrocytes stimulated by thapsigargin(TG)exhibit heightened ERS and significantly increase the expression of ERS-associated proteins.
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