3 research outputs found
Laser Application in Prevention of Demineralization in Orthodontic Treatment
One common negative side effect of orthodontic treatment with fixed appliances is the development of incipient caries lesions around brackets, particularly in patients with poor oral hygiene. Different methods have been used to prevent demineralization such as fluoride therapy and application of sealant to prevent caries. The recent effort to improve the resistance against the demineralization is by the application of different types of lasers. The purpose of this review article is discussing the effects of laser in prevention of demineralizationin orthodontic patients
Variations in enamel damage after debonding of two different bracket base designs: An in vitro study
Background. Bracket base design is a factor influencing shear bond strength. High shear bond strength leads to enamel crack formation during debonding. The aim of this study was to compare enamel damage variations, including the number and length of enamel cracks after debonding of two different base designs. Methods. Eighty-eight extracted human premolars were randomly divided into2 groups (n=44). The teeth in each group were bonded by two types of brackets with different base designs: 80-gauge mesh design versus anchor pylon design with pylons for adhesive retention. The number and length of enamel cracks before bonding and after debonding were evaluated under an optical stereomicroscope ×40 in both groups. Mann-Whitney U test was used to compare the number of cracks between the two groups. ANCOVA was used for comparison of crack lengths after and before debonding in each group and between the two groups. Results. There was a significant increase in enamel crack length and numbers in each group after debonding. There was no significant difference in enamel crack numbers after debonding between the two groups, whereas the length of enamel cracks was significantly greater in anchor pylon base design after debonding. Conclusion. Bracket bases with pylon design for adhesive retention caused more iatrogenic debonding damage to enamel surface
Predictors of ventricular tachycardia induction in syncopal patients with mild to moderate left ventricular dysfunction
Background: In patients with mild to moderate left ventricular dysfunction (LVD) (35% £ LVEF
£ 50%) who present with syncope, demonstration of tachy and/or brady-arrhythmia has
prognostic value. In this group of patients electrophysiological study (EPS) is often necessary.
Methods: A total of 53 consecutive patients with mild to moderate LVD and history of
undetermined syncope underwent EPS. Sinus node function, His-Purkinje system conduction
and ventricular electrical stability were evaluated.
Results: Twenty eight patients (52.8%) had induction of sustained monomorphic ventricular
tachycardia (VT) and five (9.4%) patients had a sustained ventricular arrhythmia other than
monomorphic VT (ventricular flutter, ventricular fibrillation, and polymorphic VT) induced
during EPS. Abnormal sinus node function and/or His-Purkinje system conduction was
found in five (9.4%) patients. Age, gender, history of myocardial infarction, type of underlying
heart disease and history of revascularization were not predictors of VT induction. Wide QRS
morphology independently, and lower left ventricular ejection fraction and presence of
pathologic q wave in precordial leads dependently, could increase risk of VT induction.
Conclusions: The EPS can determine which patient with syncope and mild to moderate LVD
is likely to benefit from placing an ICD for prevention of sudden cardiac death. Pathologic
precordial q wave, wide QRS morphology and lower left ventricular ejection fraction could be
predictors of VT induction during EPS. Wide QRS morphology has an independent effect in
this category