Limits...
Effects of fluorosis and bleaching on shear bond strengths of orthodontic brackets.

Adanir N, Türkkahraman H, Güngör AY - Eur J Dent (2007)

Bottom Line: After bonding, shear bond strengths of the brackets were tested with Universal testing machine.The results showed that fluorosis only and bleaching of fluorosed teeth significantly reduced the bond strengths of the orthodontic brackets (P < .001).Although bleaching of fluorosed teeth decreased the values more, no statistically significant difference was found between fluorosis group and fluorosis+bleaching group (P > .05).

View Article: PubMed Central - PubMed

Affiliation: Assistant Professor, Department of Endodontics, Faculty of Dentistry, University of Suleyman Demirel.

ABSTRACT

Objectives: To evaluate the effects of fluorosis and bleaching on shear bond strengths of orthodontic brackets.

Methods: A total of 45 (30 fluorosed and 15 non-fluorosed) non-carious freshly extracted human permanent premolar teeth which were extracted for orthodontic reasons and without any caries or visible defects were used in this study. Fluorosed teeth were selected according to the modified Thylstrup and Fejerskov index (TFI), which is based on the clinical changes in fluorosed teeth. First group consisted of 15 fluorosed teeth. Second group of fluorosed teeth were bleached with a 35% hydrogen peroxide office bleaching agent. Third group served as control. No bleaching procedure was applied. Orthodontic brackets were bonded with a light cure composite resin and cured with a halogen light. After bonding, shear bond strengths of the brackets were tested with Universal testing machine.

Results: The results showed that fluorosis only and bleaching of fluorosed teeth significantly reduced the bond strengths of the orthodontic brackets (P < .001). Although bleaching of fluorosed teeth decreased the values more, no statistically significant difference was found between fluorosis group and fluorosis+bleaching group (P > .05).

Conclusions: Fluorosis and bleaching of fluorosed teeth reduce bracket bond strength to enamel, but the bond strength with these still exceed the minimum 6 to 8 MPa required to expect adequate clinical performance.

No MeSH data available.


Related in: MedlinePlus

Schematic representation of the specimen in the test machine. The standard knife edge was positioned to make contact with the bonded specimen and directed parallel to the long axis of the crown of the tooth.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2609915&req=5

f2-0010230: Schematic representation of the specimen in the test machine. The standard knife edge was positioned to make contact with the bonded specimen and directed parallel to the long axis of the crown of the tooth.

Mentions: All specimens were stored in distilled water at 37°C for 24 hours and thermocycled for 500 cycles between 5°C and 55°C, using a dwell time of 30 seconds. Each specimen was loaded into universal testing machine (Lloyd; Fareham, Hants, England) using Nexjen software for testing, with the long axis of the specimen being perpendicular to the direction of the applied force. The standard knife edge was positioned to make contact with the bonded specimen (Figure 2). Bond strength was determined in the shear mode at a crosshead speed of 0.5 mm/min until fracture occurred. Values of failure loads (N) were recorded and converted into megapascals (MPa) by dividing the failure load (N) by the surface area of the bracket base (9.63 mm2).


Effects of fluorosis and bleaching on shear bond strengths of orthodontic brackets.

Adanir N, Türkkahraman H, Güngör AY - Eur J Dent (2007)

Schematic representation of the specimen in the test machine. The standard knife edge was positioned to make contact with the bonded specimen and directed parallel to the long axis of the crown of the tooth.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2609915&req=5

f2-0010230: Schematic representation of the specimen in the test machine. The standard knife edge was positioned to make contact with the bonded specimen and directed parallel to the long axis of the crown of the tooth.
Mentions: All specimens were stored in distilled water at 37°C for 24 hours and thermocycled for 500 cycles between 5°C and 55°C, using a dwell time of 30 seconds. Each specimen was loaded into universal testing machine (Lloyd; Fareham, Hants, England) using Nexjen software for testing, with the long axis of the specimen being perpendicular to the direction of the applied force. The standard knife edge was positioned to make contact with the bonded specimen (Figure 2). Bond strength was determined in the shear mode at a crosshead speed of 0.5 mm/min until fracture occurred. Values of failure loads (N) were recorded and converted into megapascals (MPa) by dividing the failure load (N) by the surface area of the bracket base (9.63 mm2).

Bottom Line: After bonding, shear bond strengths of the brackets were tested with Universal testing machine.The results showed that fluorosis only and bleaching of fluorosed teeth significantly reduced the bond strengths of the orthodontic brackets (P < .001).Although bleaching of fluorosed teeth decreased the values more, no statistically significant difference was found between fluorosis group and fluorosis+bleaching group (P > .05).

View Article: PubMed Central - PubMed

Affiliation: Assistant Professor, Department of Endodontics, Faculty of Dentistry, University of Suleyman Demirel.

ABSTRACT

Objectives: To evaluate the effects of fluorosis and bleaching on shear bond strengths of orthodontic brackets.

Methods: A total of 45 (30 fluorosed and 15 non-fluorosed) non-carious freshly extracted human permanent premolar teeth which were extracted for orthodontic reasons and without any caries or visible defects were used in this study. Fluorosed teeth were selected according to the modified Thylstrup and Fejerskov index (TFI), which is based on the clinical changes in fluorosed teeth. First group consisted of 15 fluorosed teeth. Second group of fluorosed teeth were bleached with a 35% hydrogen peroxide office bleaching agent. Third group served as control. No bleaching procedure was applied. Orthodontic brackets were bonded with a light cure composite resin and cured with a halogen light. After bonding, shear bond strengths of the brackets were tested with Universal testing machine.

Results: The results showed that fluorosis only and bleaching of fluorosed teeth significantly reduced the bond strengths of the orthodontic brackets (P < .001). Although bleaching of fluorosed teeth decreased the values more, no statistically significant difference was found between fluorosis group and fluorosis+bleaching group (P > .05).

Conclusions: Fluorosis and bleaching of fluorosed teeth reduce bracket bond strength to enamel, but the bond strength with these still exceed the minimum 6 to 8 MPa required to expect adequate clinical performance.

No MeSH data available.


Related in: MedlinePlus