A Radical-Free Approach to Teeth Whitening

Background: Traditional bleaching agents based on hydrogen peroxide (HP) or carbamide peroxide (CP) have adverse soft and hard tissue effects. Objectives: This study tested a novel formulation of phthalimidoperoxycaproic acid (PAP) with additives to optimise its safety and effectiveness. Methods: A novel gel (PAP+) was formulated. Laboratory studies assessed effects of six 10-minute exposures to PAP+ vs. commercial CP and HP gels, using surface profilometry and microhardness. The effectiveness of PAP+ in vitro against complex polyphenol stains on enamel was compared to 6% HP. Results: Unlike HP gels, PAP+ gel did not erode enamel. Unlike both CP and HP gels, PAP+ gel did not reduce the surface microhardness of enamel. PAP+ gel on used on polyphenol stains was superior to 6% HP. In this model, six repeated 10-minute treatments with PAP+ gel could improve the shade by approximately eight VITA® Bleachedguide shades. Conclusions: These laboratory results support the safety and effectiveness of this new PAP formula and its use as an alternative to CP and HP with superior safety and effectiveness.

Surface Profilometry

As outlined in the previous chapter, existing technologies for surface profilometry show certain drawbacks in terms of resolution, dynamic measurement range, three-dimensional measurement capabilities and speed. The following chapter introduces a novel approach to surface profilometry which aims to provide solutions to the problems named. The basic setup for all experiments is centered around a two-beam interferometer of the Michelson type.

Changes in Enamel Topography with the Contemperary Orthodontic Adhesives: A Pilot Study

Introduction: The self-etching primer system consists of etchant and primer dispersed in a single unit. The etching and priming are merged as a single step leading to fewer stages in bonding procedure and reduction in the number of steps that also reduces the chance of introduction of error, resulting in saving time for the clinician. It also results in smaller extent of enamel decalcification. Aim: To compare the Shear Bond Strength (SBS) of orthodontic molar tubes bonded with conventional acid etching system and Self-Etch Primers (SEP) and to study the surface appearance of enamel after debonding using surface profilometry and scanning electron microscope. Materials and Methods: The sample of this in-vitro study consisted of sixty caries free, intact extracted mandibular first molar teeth. A molar tube of 0.018” Roth prescription with micro etched base was bonded to each molar with two different bonding agents. All the molar tubes were subsequently tested for evaluation of shear bond strength with a universal testing machine. Surface Profilometry and Scanning Electron Microscope (SEM) was used to evaluate the effect of various light cure adhesives on the enamel morphology. Results: Transbond-XT exhibited the highest bond strength (22.6 MPa) closely followed by Transbond Plus SEP (19.6 MPa). However, Transbond-XT sample also had higher surface roughness and enamel alterations as compared to the Transbond Plus SEP. Conclusion: The adequate bond strength of self-etching primers, less deleterious effects on the enamel and less chair side time due to absence of acid etching makes it a good option for routine use in orthodontics.