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Biomedical subjects

M F Sfondrini

Publications and source records attributed to M F Sfondrini.

8 recordsLinked to original sources
PubMed2003

Orthodontic composite resin bond strength with conventional light and Power Slot curing.

OBJECTIVES: the purpose of this clinical trial was to compare the clinical performance of a new composite resin using two different kind of light curing systems, one conventional and one turbo boosted in a split-mouth design, by using both systems for direct bonding of orthodontic stainless steel brackets in every patient. MATERIALS AND METHODS: fifty patients, 32 females and 18 males, of which 13 were adults (> 18 years of age) with fixed appliances were followed for a mean period of 12 months (range 6-16 months). The performance of 1200 steel brackets was evaluated: 600 were bonded with a conventional light curing (Kulzer light curing machine), curing every bracket for 20 seconds using Quick Cure Composite resin (Reliance Orthodontics), 600 were bonded with a new curing light machine (Reliance Ortho 2000 curing light with Power slot), curing every bracket for 6 seconds. Brackets were bonded both on permanent and on deciduous teeth, since many of these patients were growing patients. RESULTS: the conventional light curing recorded an overall failure rate (26 brackets - 4,3%) significantly higher (p< 0.0360) than Power Slot light curing (13 brackets -2,3%). There were no statistically significant differences (p>0.07) between the failure rates in the upper and lower arches with either light curing systems and also in between anterior and posterior areas. A significant difference was evident, however, among the failure rate of upper total and lower total (p<0.0463) brackets bonded with both systems and was more evident in upper arches bonded with conventional curing system (p<0.0170). It was evident also a higher failure rate in the upper arch compared to the lower arch bonded with conventional light (p<0.0269). CONCLUSIONS: the Power Slot light curing was more effective. But both bonding systems failed mainly at the enamel-adhesive interface, without causing damage to the enamel.

Adhesiveness↗
PubMed2002

Upper molar distalization: a critical analysis.

Traditional upper molar distalization techniques require patient co-operation with the headgear or elastics. Recently, several different intraoral procedures have been introduced to minimize the need for patient co-operation. This article reviews the appliances currently available for maxillary molar distalization and critically analyses their dentoalveolar and skeletal effects.

Humans↗
PubMed2002

Halogen versus high-intensity light-curing of uncoated and pre-coated brackets: a shear bond strength study.

AIM: To evaluate the shear bond strengths of adhesive pre-coated brackets (APC) and conventional uncoated brackets (Victory) cured with two different light-curing units: a conventional halogen light (Visilux 2) and a micro-xenon light (Aurys). SETTING: Ex vivo study MATERIALS AND METHODS: Sixty freshly extracted bovine permanent mandibular incisors were randomly assigned to one of four groups, each group consisting of 15 specimens. Two groups (one for each type of bracket) were exposed to the halogen light for 20 seconds and used as controls. The remaining two groups were cured with the micro-xenon light for 2 seconds. After 24 hours, all samples were tested in a shear mode on an Instron Machine. Analysis was by two-way ANOVA with Scheffé's test for comparisons, Kaplan-Meier survival estimates, and Cox model. The Chi-square (chi(2)) test was used to determine significant differences in the ARI scores. RESULTS: The mean shear bond strength of the uncoated brackets cured with Visilux 2 was significantly higher than those of all the other groups tested. Both groups cured with Visilux 2 produced significantly higher mean shear bond strengths than those of the corresponding groups cured with Aurys. No statistically significant differences were found between the two groups cured with Aurys. CONCLUSIONS: Compared to halogen light-curing, the micro-xenon light enables the clinician to reduce significantly the curing time of both APC and uncoated brackets, and although significantly lower, their shear bond strengths may be clinically acceptable.

Analysis of Variance↗
PubMed2001

Effects of conventional and high-intensity light-curing on enamel shear bond strength of composite resin and resin-modified glass-ionomer.

The purpose of this study was to evaluate the shear bond strengths of a composite resin (Transbond XT; 3M/Unitek, Monrovia, Calif) and a resin-modified glass ionomer (Fuji Ortho LC; GC America Inc, Alsip, Ill) cured with 2 different light-curing units: a conventional visible light unit (Ortholux XT; 3M Dental Products, St Paul, Minn) and a xenon arc light unit (Plasma Arc Curing [PAC] System; American Dental Technologies, Corpus Christi, Texas). One hundred twenty freshly extracted bovine permanent mandibular incisors were randomly divided into 1 of 8 groups; each group consisted of 15 specimens. Two groups (1 group for each type of adhesive) were exposed to the visible light for 20 seconds (Transbond XT) and 40 seconds (Fuji Ortho LC), respectively, and used as control groups. The remaining 6 groups (3 for each adhesive) were cured with the xenon arc light for 2, 5, and 10 seconds. After bonding, all samples were stored in distilled water at room temperature for 24 hours and subsequently tested in a shear mode on an Instron universal testing machine (Instron Corp, Canton, Mass). For the groups bonded with Transbond XT, no statistically significant differences (P =.868) were found between the shear bond strength of the control group cured with Ortholux XT and those of the groups cured with the PAC System for 2, 5, or 10 seconds. When the shear bond strengths of the groups bonded with Fuji Ortho LC were evaluated, no statistically significant differences (P =.087) were found between the control group that was cured with Ortholux XT and those cured with the PAC System. The bond strength of the composite resin was significantly higher than that of the resin-modified glass ionomer in all the groups tested (P <.0001). The present findings indicate that, compared with visible light-curing, the xenon arc light enables the clinician to significantly reduce the curing time of both bonding agents, without affecting their shear bond strengths. Therefore, xenon arc light sources can be recommended as an advantageous alternative for curing both composite resins and resin-modified glass ionomers.

Acid Etching, Dental↗
PubMed1997

The use of spiral computed tomography in the localization of impacted maxillary canines.

PURPOSE: To compare spiral CT with conventional radiography in planning the orthodontic treatment of impacted permanent maxillary canines. METHODS: Nineteen patients with 29 malpositioned permanent maxillary canines (15 palatal and 12 buccal impactions, one ectopic and one transposition) were examined with conventional panoramic and lateral cephalometric radiography and with spiral CT (at 1 mm slice thickness, and 1:1 or 2:1 pitch) using multiplanar (MPR) and 3D reconstruction. RESULTS: Conventional radiography failed to depict root resorption especially on the buccal surfaces of the incisor teeth. CT located impacted teeth better. Contact between impacted maxillary canines and incisor roots was demonstrated in 26 cases and root resorption in eight. MPR proved to be superior for the orientation of impacted teeth, and, in two cases, confirmed the presence of minimal root lesions for which axial images had proved inconclusive. The 3D reconstructions were useful in targeting the MPR. CONCLUSIONS: CT facilitates the treatment of impacted canine especially when the teeth are very oblique to the arch. Root resorption is better demonstrated especially on the palatal and buccal surfaces of the adjacent incisors. Spiral CT reduces examination time and risk of accidental movement, thus optimizing MPR quality. Examination at 2:1 pitch enables a significant reduction in radiation exposure without loss of image quality.

Adolescent↗