Radiologically determined orthodontically induced external apical root resorption in incisors after non-surgical orthodontic treatment of class II division 1 malocclusion: a systematic review.

This study aims to critically evaluate orthodontically induced external apical root resorption (OIEARR) in incisors of patients undergoing non-surgical orthodontic treatment of class II division 1 malocclusion by a systematic review of the published data. An electronic search of two databases was performed; the bibliographies of relevant articles were also reviewed. Studies were included if they examined the amount of OIEARR in incisors produced during non-surgical orthodontic treatment of individuals with class II division I malocclusion in the permanent dentition. Individuals had no previous history of OIEARR, syndromes, pathologies, or general diseases. Study selections, risk of bias assessment, and data extraction were performed in duplicate. Eight studies of moderate methodological quality were finally included. An increased prevalence (65.6% to 98.1%) and mild to moderate severity of OIEARR (<4 mm and <1/3 original root) were reported. No sex difference in root resorption was found. For the maxillary incisors, there was no evidence that either the central or lateral incisor was more susceptible to OIEARR. A weak to moderate positive correlation between treatment duration and root resorption, and anteroposterior apical displacement and root resorption was found. Current limited evidence suggests that non-surgical comprehensive orthodontic treatment to correct class II division 1 malocclusions causes increased prevalence and severity of OIEARR the more the incisor roots are displaced and the longer this movement takes.

Management of ankylosed primary molars with premolar successors: a systematic review.

BACKGROUND: The authors conducted a systematic review to determine the clinical prognosis of and methods of managing ankylosed primary molars with permanent successors. METHODS: The authors searched electronic databases (PubMed, Scopus, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Cochrane Database of Systematic Reviews and Google Scholar) up to April 2012 with the assistance of a librarian specializing in health sciences databases. They also searched the gray literature. They selected clinical studies in which investigators assessed the prognosis of ankylosed primary molars with permanent successors; they also hand searched references of the selected articles to identify any additional studies that the electronic search may have missed. RESULTS: The authors identified 3,529 original articles from the electronic database search and none from the hand search. Once selection criteria were applied, only four articles met all inclusion criteria and were included. The number of patients studied ranged from 15 to 107. The number of ankylosed primary molars investigated ranged from 26 to 263. CONCLUSIONS: Ankylosed primary molars often manifest with mild to moderate progressive infraocclusion. Conservative monitoring of ankylosed primary molars is recommended. The clinician should consider extraction if the permanent successor has an altered path of eruption, if the ankylosed primary molar is severely infraoccluded with the adjacent teeth tipping to prevent the successor from erupting, or both. The ankylosed molar often exfoliates spontaneously within six months; however, when exfoliation is more delayed, arch-length loss, occlusal disturbance, hooked roots or impaction of permanent successors may occur. Practical Implications. Ankylosed primary molars initially should be monitored closely for up to six months. If they do not exfoliate spontaneously, they should be removed, because arch-length loss, alveolar bone defects, impacted permanent successors and occlusal disturbances often occur when the removal is delayed.

Radiographic comparison of the extent of orthodontically induced external apical root resorption in vital and root-filled teeth: a systematic review.

OBJECTIVE: to critically analyse the available scientific literature radiographically comparing the incidence of orthodontically induced external apical root resorption (OIEARR) in human root-filled and vital teeth. METHODS: Several electronic databases (MEDLINE, PubMed, EMBASE, Scopus, Web of Science, CINAHL, and the Cochrane Database of Systematic Reviews and Google Scholar) were searched without limits, with the assistance of a senior librarian specialized in Health Sciences database searches. Human, in vivo studies that radiographically compared root resorption following fixed orthodontic treatment in root-filled and vital teeth were selected for full article review. Additionally, the bibliographies of the finally selected articles were hand searched to identify any relevant publications that were not identified by electronic searches. The lowest levels of evidence accepted for inclusion were case controls or cohort studies. Two authors independently reviewed and extracted data from selected studies. RESULTS: A total of 165 original articles were identified from electronic database searches and 2 from hand searches. Once selection criteria were applied, only four articles met all inclusion criteria, and individual analysis of the selected articles was undertaken. CONCLUSIONS: Based on available evidence, root-filled teeth do not appear to be more susceptible to OIEARR than their analogous vital teeth.

A high affinity interaction of plasminogen with fibrin is not essential for efficient activation by tissue-type plasminogen activator.

Fibrin (Fn) enhances plasminogen (Pg) activation by tissue-type plasminogen activator (tPA) by serving as a template onto which Pg and tPA assemble. To explore the contribution of the Pg/Fn interaction to Fn cofactor activity, Pg variants were generated and their affinities for Fn were determined using surface plasmon resonance (SPR). Glu-Pg, Lys-Pg (des(1-77)), and Mini-Pg (lacking kringles 1-4) bound Fn with K(d) values of 3.1, 0.21, and 24.5 µm, respectively, whereas Micro-Pg (lacking all kringles) did not bind. The kinetics of activation of the Pg variants by tPA were then examined in the absence or presence of Fn. Whereas Fn had no effect on Micro-Pg activation, the catalytic efficiencies of Glu-Pg, Lys-Pg, and Mini-Pg activation in the presence of Fn were 300- to 600-fold higher than in its absence. The retention of Fn cofactor activity with Mini-Pg, which has low affinity for Fn, suggests that Mini-Pg binds the tPA-Fn complex more tightly than tPA alone. To explore this possibility, SPR was used to examine the interaction of Mini-Pg with Fn in the absence or presence of tPA. There was 50% more Mini-Pg binding to Fn in the presence of tPA than in its absence, suggesting that formation of the tPA-Fn complex exposes a cryptic site that binds Mini-Pg. Thus, our data (a) indicate that high affinity binding of Pg to Fn is not essential for Fn cofactor activity, and (b) suggest that kringle 5 localizes and stabilizes Pg within the tPA-Fn complex and contributes to its efficient activation.

The validity and reliability of mixed-dentition analysis methods: a systematic review.

BACKGROUND: The authors conducted a literature review to determine the validity and reliability of mixed-dentition analysis (MDA) methods used to predict permanent tooth size in the mixed dentition and to evaluate the effect of relevant variables. TYPES OF STUDIES REVIEWED: The authors searched eight online databases for studies of MDA. They selected 39 articles. Inclusion criteria included assessment of mesiodistal tooth width predictions of canines and premolars, use of study-model measurements with or without radiographs, reliability and validity of MDA values and a minimum sample size of 10. RESULTS: All MDA methods had positively correlated validity and high intrarater reliability. Mean differences were less than 2 millimeters with correlation coefficients that tended to be above 0.6. Correlation coefficients were less variable with multiple linear regression equations (MLREs) than with simple linear regression equations (SLREs) with the study-model method, but the opposite was true with the radiographic method. Polymorphisms based on ethnicity, sex, jaw or side of mouth did not meaningfully influence the validity of SLRE predictions, but some differences were apparent with the use of MLRE predictions. CLINICAL IMPLICATIONS: The results of this review call into question the clinical implications of the multiple variations of MDA that have been described in the literature.

Crystallization of calcium oxalates is controlled by molecular hydrophilicity and specific polyanion-crystal interactions.

To gain more insight into protein structure-function relationships that govern ectopic biomineralization processes in kidney stone formation, we have studied the ability of urinary proteins (Tamm-Horsfall protein, osteopontin (OPN), prothrombin fragment 1 (PTF1), bikunin, lysozyme, albumin, fetuin-A), and model compounds (a bikunin fragment, recombinant-, milk-, bone osteopontin, poly-L-aspartic acid (poly asp), poly-L-glutamic acid (poly glu)) in modulating precipitation reactions of kidney stone-related calcium oxalate mono- and dihydrates (COM, COD). Combining scanning confocal microscopy and fluorescence imaging, we determined the crystal faces of COM with which these polypeptides interact; using scanning electron microscopy, we characterized their effects on crystal habits and precipitated volumes. Our findings demonstrate that polypeptide adsorption to COM crystals is dictated first by the polypeptide's affinity for the crystal followed by its preference for a crystal face: basic and relatively hydrophobic macromolecules show no adsorption, while acidic and more hydrophilic polypeptides adsorb either nonspecifically to all faces of COM or preferentially to {100}/{121} edges and {100} faces. However, investigating calcium oxalates grown in the presence of these polypeptides showed that some acidic proteins that adsorb to crystals do not affect crystallization, even if present in excess of physiological concentrations. These proteins (albumin, bikunin, PTF1, recombinant OPN) have estimated total hydrophilicities from 200 to 850 kJ/mol and net negative charges from -9 to -35, perhaps representing a "window" in which proteins adsorb and coat urinary crystals (support of excretion) without affecting crystallization. Strongest effects on crystallization were observed for polypeptides that are either highly hydrophilic (>950 kJ/mol) and highly carboxylated (poly asp, poly glu), or else highly hydrophilic and highly phosphorylated (native OPN isoforms), suggesting that highly hydrophilic proteins strongly affect precipitation processes in the urinary tract. Therefore, the level of hydrophilicity and net charge is a critical factor in the ability of polypeptides to affect crystallization and to regulate biomineralization processes.