Effect of Adhesion Boosters on the Shear Bond Strength of New Brackets Bonded to a Debonded Tooth Surface - An In vitro Study.

CONTEXT: Effect of adhesion boosters on shear bond strength of orthodontic brackets. AIM: The aim is to evaluate the shear bond strength and adhesive remnant index (ARI) score of new brackets bonded to a debonded tooth surface with and without the use of adhesion boosters. SETTINGS AND DESIGNS: In vitro comparative study. MATERIALS AND METHODS: Adhesion boosters: Enhance LC (Reliance, Itasca III) All Bond 2 (Bisco, Schaumsburg) and the Composite adhesives Transbond XT (3M UNITEK) Enlight (ORMCO) were used in this study. One hundred and eight extracted maxillary first premolar teeth were bonded with light cure composite to etched tooth surface. The brackets were then debonded with debonding pliers after 1 week and it was polished with low speed tungston carbide bur and rubber cup. The teeth were divided into six groups and they were etched, washed, and dried again. New brackets were rebonded to the tooth surface using composites with or without adhesion boosters. Then, the shear bond strength value was calculated for each bracket with a universal testing machine. ARI scores were also evaluated. STATISTICAL ANALYSIS USED: One-way ANOVA and least significant difference post hoc test was used for the association between variables. Probability value (P < 0.05) was considered statistically significant. RESULTS: The results showed a statistically significant difference between the groups with a P < 0.001. There was no significant difference in ARI scores between the groups (P = 0.15). CONCLUSIONS: Both the adhesion boosters significantly improved the shear bond strength of orthodontic brackets. There was no statistically significant difference in the ARI scores.

Effect of Displacement of Bracket Position after Initial Placement on Shear Bond Strength: An In vitro Study.

CONTEXT: Displacement of bracket after initial placement on tooth surface in the precure phase of bonding influences the shear bond strength. AIMS: The aim of this study was to evaluate the influence of bracket displacement during the precure phase after initial placement on the tooth surface on shear bond strength of chemical cure and light cure composites. SETTINGS AND DESIGN: In vitro experimental study. SUBJECTS AND METHODS: Stainless steel orthodontic premolar brackets were bonded to the buccal surfaces of 88 maxillary 1st premolar teeth. Teeth were divided into four groups: (1) Group 1 - Control group for light-cure composites, (2) Group 2 - Displacement group for light-cure composites, (3) Group 3 - Control group for chemical cure composites, and (4) Group 4 -Displacement group for chemical cure composites. In the control groups, the brackets were bonded with no precure bracket displacement. In the displacement groups, the brackets were bonded with 2 mm precure linear displacement. Photoactivation was carried out for light-cure composites. Shear bond strength tests were carried out using the universal testing machine. Statistical analysis used: Data were analyzed using the one-way analysis of variance test. RESULTS: The mean shear bond strength of Groups 1, 2, 3, and 4 were observed to be 14.49 ± 0.75, 13.40 ± 0.61, 12.34 ± 0.53, and 11.55 ± 2.43MPa, respectively, with the displacement groups showing lower shear bond strength when compared to the control groups. Whether displaced or not, chemically cured composites showed lower bond strength when compared to light-cured composites. CONCLUSIONS: Displacement of brackets during bracket placement seemed to reduce the enamel bond strength after the final positioning of the bracket.

Evaluation of Biomechanical Properties of Four Loops at Different Activation: A Finite Element Method Study.

AIM: The aim of the study was to evaluate the force, moment, and moment/force ratio (M/F) generated by activating T loop, Kalra Simultaneous Intrusion and Retraction (KSIR) loop, Omega loop, and Teardrop loop made of titanium molybdenum alloy (TMA) wire with different preactivation bends at 1, 2, and 4 mm activation. MATERIALS AND METHODS: Finite element method (FEM) models of the four loops were created and different preactivation bends were placed. The loops were then activated and analyzed for force, moment, and M/F ratio using ANSYS software. RESULTS: In loops without preactivation bends, highest force values were generated by Omega loop, whereas T loop had the least force value. The mean value for the M/F in the alpha segment was almost similar. In loops with preactivation bend, the force was highest in Teardrop loop, whereas T loop had the least force value. The mean value for the M/F in the alpha segment was almost similar in all the loops. CONCLUSION: T loop with preactivation bend shows the most favorable properties. CLINICAL SIGNIFICANCE: T loop is comparatively reliable for the frictionless mechanics for the space closure than the other loops evaluated in clinical use.

Platelets and Their Pathways in Dentistry: Systematic Review.

Advancing research in medicine and technology has benefitted the mankind immensely with its contribution toward an improved life quality and increased life expectancy. The inability of a human body to autoregenerate has resulted in an increased demand for newer and healthier tissues and organs. Therefore, the restoration of naturally replicated tissue components has become a subject of interest for the scientific community lately. There was felt an intense quest for promoting strategies that could restore tissue regeneration and fuel the field of regenerative medicine. It was then the role of platelets was accounted for its wound healing and regenerative effects. Consequently, the use of platelet concentrates to improve wound healing, and bone formation was explored, which was considered to be possible because platelets contain high quantities of growth factors which would be able to stimulate cell proliferation, matrix remodeling, and angiogenesis, thereby establishing a new era of research with the successful application of innovative medical therapies focused on healing damaged tissues or regenerate the affected organs.