Search results for "Orthodontics."
showing 10 items of 920 documents
Inclusion of the periodontal ligament in studies on the biomechanical behavior of fiber post-retained restorations: An in vitro study and three-dimen…
2016
Endodontically treated teeth are known to have reduced structural strength. Periodontal ligament may influence fracture resistance. The purpose of this study was to assess the influence of including the periodontal ligament in biomechanical studies about endodontically treated and restored teeth. Forty human maxillary central incisors were treated endodontically and randomly divided into four groups: non-crowned (with and without an artificial ligament) and crowned (with and without an artificial ligament) with glass-ceramic crowns. All groups received prefabricated glass-fiber posts and a composite resin core. Specimens were tested, under a flexural–compressive load, until failure occurre…
Evaluation of the effect of three innovative recyling methods on the shear bond strength of stainless steel brackets-an in vitro study
2016
Background Orthodontists are commonly faced with the decision of what to do with debonded or inaccurately positioned brackets. An economical option to this dilemma is to recycle the brackets. Many recycling methods have been proposed, but the optimal bond strength of these recycled brackets needs further evaluation. Objectives: To evaluate and compare the effect of three recycling methods: (i) Sandblasting (ii) Sandblasting / direct flaming (iii) Sandblasting /direct flaming /acid bath solution on shear bond strength (SBS) of stainless steel brackets. Material and Methods Eighty human premolars were bonded with premolar stainless steel brackets as per manufacturer’s instructions. The teeth …
Comparative evaluation of orthodontic bracket base shapes on shear bond strength and adhesive remnant index : an in vitro study
2017
BACKGROUND The objective of this study was to evaluate the effect of orthodontic bracket base shape on shear bond strength and adhesive remnant index. MATERIAL AND METHODS In this in vitro study using 140 bovine incisors, shear bond strength (SBS) of brackets with different base shapes (rectangle, flower, round, heart, diamond, star, and football) were measured with an Instron testing machine and tested until bond failure. Adhesive Remnant Index (ARI) scoring was evaluated after debonding to evaluate the location of bond failure. Descriptive and one-way ANOVA post-hoc Tukey statistical analyses were performed with a statistical significance set at p≤0.05. RESULTS Statistically significant d…
The impact of different surface treatments on the shear bond strength of orthodontic metal brackets applied to different CAD/CAM composites
2020
Background To investigate the shear bond strength (SBS) of orthodontic metal brackets applied to different CAD/CAM composites treated with different surface treatments. Material and Methods Specimens of two CAD/CAM composites were obtained of Lava Ultimate (LU; n=60) and Brilliant Crios (BC; n=60) which were randomly separated into six subgroups (n=10) according to the surface treatment: control (CTL); sandblasting (SB); sandblasting and silane (SBSL); hydrofluoric acid (HF); hydrofluoric acid and silane (HFSL); and Monobond Etch&Prime (MEP). The mandibular central incisor metal brackets were bonded with a light-cure adhesive. The SBS data were analyzed using the two-way analysis of varianc…
Enamel evaluation by scanning electron microscopy after debonding brackets and removal of adhesive remnants
2017
Made available in DSpace on 2022-04-29T08:27:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-01 Background: The bonding of accessories in the dental crown during the orthodontic treatment creates microporosities, thus promoting micromechanical retention of the adhesive to the enamel structure. After debonding brackets, at the end of the active orthodontic treatment, a certain amount of adhesive remnants must be mechanically removed from the enamel. The objective of this study was to compare, by means of scanning electron microscopy, three different methods to remove the adhesive remnants after orthodontic bracket removal. Material and Methods: An experimental analytical study w…
Effect of addition of bioactive glass to resin modified glass ionomer cement on enamel demineralization under orthodontic brackets
2019
Background Enamel demineralization and white spot lesions around orthodontic brackets is a common problem associated with fixed orthodontic treatment. Glass ionomer cements (GICs) are commonly used for bracket bonding and recently, bioactive glass (BAG) was added to GICs to enhance deposition of calcium phosphate in adjacent dental structure. This study sought to assess the effect of addition of BAG particles to resin modified GIC (RMGIC) on enamel demineralization under orthodontic brackets. Material and methods In this in vitro, experimental study, 60 sound human premolars were immersed in distilled water at 6°C. The teeth were randomly divided into three groups. Using a sticker, a window…
Effects of recycling and bonding agent application on bond strength of stainless steel orthodontic brackets
2014
Objectives: 1) to assess different methods of recycling orthodontic brackets, 2) to evaluate Shear Bond Strength (SBS) of (a) new, (b) recycled and (c) repeated recycled stainless steel brackets (i) with and (ii) without bracket base primer. Study Design: A total of 180 extracted human premolar teeth and 180 premolar stainless steel brackets were used. One hundred teeth and 100 brackets were divided into five groups of 20-teeth each. Four methods of recycling orthodontic brackets were used in each of the first four groups while the last one (group V) was used as the control. Groups (I-V) were subjected to shear force within half an hour until the brackets debond. SBS was measured and the me…
Comparison of frictional forces during the closure of extraction spaces in passive self-ligating brackets and conventionally ligated brackets using t…
2019
Background This study compared the frictional force resulting from the bracket/archwire interface and the stress at the root/periodontal ligament/bone interface, between passive self-ligating brackets and conventionally ligated brackets, during the space closure stage. Material and methods A cone beam tomography was taken to a female patient that required extraction of upper first premolars and passive self-ligating system; three months after its activation, a cone beam tomography was taken again. The designs of the maxillary bone and the entire system were possible through tomography images and stereomicroscopic photographs. Validation of the Finite Element Method (FEM) was achieved compar…
Effect of retention design of artificial teeth and implant-supported titanium CAD-CAM structures on fracture resistance
2014
Background For implant-supported hybrid prostheses, high mastication forces and reduced acrylic resin thickness over a metal substructure often cause failures arising from tooth or resin fractures. To assay fracture resistance of artificial teeth and resin in implant-supported hybrid prostheses in relation to the titanium structure and retention design supporting teeth. Material and Methods 40 specimens bearing incisors were divided into four groups according to the titanium structure supporting the teeth and the type of load force applied: Group I (Control; n=10): Application of static loading to ten incisors set over a metal structure with internal retention. Group II (Control; n=10): App…
Association between mandibular second molars calcification stages in the panoramic images and cervical vertebral maturity in the lateral cephalometri…
2019
Background Determination of maturation and evaluation of growth potential is extremely important in clinical orthodontics. The purpose of this study was to evaluate the diagnostic performance of the mandibular second molar calcification stages for identification of growth phases. Material and Methods In this cross-sectional descriptive study, samples were derived from panoramic radiographs and lateral cephalograms of 125 subjects (61 males and 64 females) with age ranging from 8 to 17 years and estimates of dental maturity (Demirjian Index [DI]) and skeletal maturity (Cervical vertebral maturation indicators CVMI]) were made. Correlations between DI and CVMI were shown by Spearman's correla…