Author
Asgeir Sigurdsson
Other affiliations: University of North Carolina at Chapel Hill
Bio: Asgeir Sigurdsson is an academic researcher from New York University. The author has contributed to research in topics: Root canal & Traumatology. The author has an hindex of 40, co-authored 86 publications receiving 8482 citations. Previous affiliations of Asgeir Sigurdsson include University of North Carolina at Chapel Hill.
Papers published on a yearly basis
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TL;DR: Three genetic variants of the gene encoding catecholamine-O-methyltransferase determine COMT activity in humans that inversely correlates with pain sensitivity and the risk of developing TMD.
Abstract: Pain sensitivity varies substantially among humans. A significant part of the human population develops chronic pain conditions that are characterized by heightened pain sensitivity. We identified three genetic variants (haplotypes) of the gene encoding catecholamine-O-methyltransferase (COMT) that we designated as low pain sensitivity (LPS), average pain sensitivity (APS) and high pain sensitivity (HPS). We show that these haplotypes encompass 96% of the human population, and five combinations of these haplotypes are strongly associated (P 5 0.0004) with variation in the sensitivity to experimental pain. The presence of even a single LPS haplotype diminishes, by as much as 2.3 times, the risk of developing myogenous temporomandibular joint disorder (TMD), a common musculoskeletal pain condition. The LPS haplotype produces much higher levels of COMT enzymatic activity when compared with the APS or HPS haplotypes. Inhibition of COMT in the rat results in a profound increase in pain sensitivity. Thus, COMT activity substantially influences pain sensitivity, and the three major haplotypes determine COMT activity in humans that inversely correlates with pain sensitivity and the risk of developing TMD.
1,209 citations
TL;DR: These Guidelines are developed as a consensus statement after a comprehensive review of the dental literature and working group discussions and represent the current best evidence and practice based on that literature search and expert opinions.
Abstract: Avulsion of permanent teeth is one of the most serious dental injuries, and a prompt and correct emergency management is very important for the prognosis. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the task group. The guidelines represent the current best evidence and practice based on literature research and professionals' opinion. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion or majority decision of the task group. Finally, the IADT board members were giving their opinion and approval. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of avulsed permanent teeth.
563 citations
TL;DR: It is indicated that NaOCl irrigation with rotary instrumentation is an important step in the reduction of canal bacteria during endodontic treatment, however this method could not consistently render canals bacteria-free.
530 citations
TL;DR: The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions as mentioned in this paper, which represents the best current evidence based on literature search and professional opinion.
Abstract: Traumatic dental injuries (TDIs) of permanent teeth occur frequently in children and young adults. Crown fractures and luxations are the most commonly occurring of all dental injuries. Proper diagnosis, treatment planning and followup are important for improving a favorable outcome. Guidelines should assist dentists and patients in decision making and for providing the best care effectively and efficiently. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the best current evidence based on literature search and professional opinion. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of TDIs. In this first article, the IADT Guidelines for management of fractures and luxations of permanent teeth will be presented.
527 citations
TL;DR: The composition of the microbial flora present in teeth after the failure of root canal therapy in a North American population was found to be mainly of 1 to 2 strains of predominantly gram-positive organisms.
Abstract: Objective: The purpose of this study was to determine the composition of the microbial flora present in teeth after the failure of root canal therapy in a North American population. These results were then compared with those of the previous Scandinavian studies. Study Design: Fifty-four root-filled teeth with persistent periapical radiolucencies were selected for retreatment. After removal of the root-filling material, the canals were sampled with paper points, and by reaming of the apical dentin. Both samples were grown under aerobic and strict anaerobic conditions. Then the bacterial growth was analyzed. Results: The microbial flora was mainly of 1 to 2 strains of predominantly gram-positive organisms. Enterococcus faecalis was the most commonly recovered bacterial species. Conclusions: Bacteria were cultivated in 34 of the 54 teeth examined in the study. E faecalis was identified in 30% of the teeth with a positive culture. (ORAL Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:579-86)
422 citations
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TL;DR: Strategies for identification of patients at risk and for prevention and possible treatment of this important entity of chronic pain are outlined.
3,365 citations
TL;DR: A review of the basic neuroscience processes of pain (the bio part of biopsychosocial, as well as the psychosocial factors, is presented) and on the development of new technologies, such as brain imaging, that provide new insights into brain-pain mechanisms.
Abstract: The prevalence and cost of chronic pain is a major physical and mental health care problem in the United States today. As a result, there has been a recent explosion of research on chronic pain, with significant advances in better understanding its etiology, assessment, and treatment. The purpose of the present article is to provide a review of the most noteworthy developments in the field. The biopsychosocial model is now widely accepted as the most heuristic approach to chronic pain. With this model in mind, a review of the basic neuroscience processes of pain (the bio part of biopsychosocial), as well as the psychosocial factors, is presented. This spans research on how psychological and social factors can interact with brain processes to influence health and illness as well as on the development of new technologies, such as brain imaging, that provide new insights into brain-pain mechanisms.
2,566 citations
TL;DR: Current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances.
2,178 citations
TL;DR: The current state of scientific evidence for the individual components of the fear-avoidance model: pain severity, pain catastrophizing, attention to pain, escape/avoidance behavior, disability, disuse, and vulnerabilities is reviewed.
Abstract: Research studies focusing on the fear-avoidance model have expanded considerably since the review by Vlaeyen and Linton (Vlaeyen J. W. S. & Linton, S. J. (2000). Fear-avoidance and its consequences in chronic musculoskeletal pain: a state of the art. Pain, 85(3), 317--332). The fear-avoidance model is a cognitive-behavioral account that explains why a minority of acute low back pain sufferers develop a chronic pain problem. This paper reviews the current state of scientific evidence for the individual components of the model: pain severity, pain catastrophizing, attention to pain, escape/avoidance behavior, disability, disuse, and vulnerabilities. Furthermore, support for the contribution of pain-related fear in the inception of low back pain, the development of chronic low back pain from an acute episode, and the maintenance of enduring pain, will be highlighted. Finally, available evidence on recent clinical applications is provided, and unresolved issues that need further exploration are discussed.
1,900 citations
TL;DR: Treatment needs to move from merely suppressing symptoms to a disease-modifying strategy aimed at both preventing maladaptive plasticity and reducing intrinsic risk.
Abstract: Neuropathic pain is triggered by lesions to the somatosensory nervous system that alter its structure and function so that pain occurs spontaneously and responses to noxious and innocuous stimuli are pathologically amplified. The pain is an expression of maladaptive plasticity within the nociceptive system, a series of changes that constitute a neural disease state. Multiple alterations distributed widely across the nervous system contribute to complex pain phenotypes. These alterations include ectopic generation of action potentials, facilitation and disinhibition of synaptic transmission, loss of synaptic connectivity and formation of new synaptic circuits, and neuroimmune interactions. Although neural lesions are necessary, they are not sufficient to generate neuropathic pain; genetic polymorphisms, gender, and age all influence the risk of developing persistent pain. Treatment needs to move from merely suppressing symptoms to a disease-modifying strategy aimed at both preventing maladaptive plasticity and reducing intrinsic risk.
1,616 citations