Orthodontic bracket bonding techniques and adhesion failures

The introduction of glass ionomer cements in orthodontics aimed to address the drawbacks of the acid-etch technique using composite resins, including demineralization, enamel damage, and potential allergic reactions. These cements release fluoride over time, potentially protecting against demineralization. Glass ionomer cements, despite their benefits in reducing adhesive residue and protecting against demineralization, showed higher bond failure rates compared to composite resins. This is attributed to their sensitivity to application techniques and moisture, along with a delayed setting time. In contrast, light-cured composite resins, preferred over chemically-cured resins in recent years, offer advantages such as ease of use, consistent handling, and controlled setting. However, early trials indicated higher bond failure rates for light-cured resins, a finding not consistently replicated in later studies. While glass ionomer cements offer certain advantages, their higher bond failure rate poses a significant limitation. Light-cured composite resins, with their user-friendly characteristics, have become the preferred choice in orthodontic bonding despite initial concerns about higher bond failure rates.

Over-reduction in tooth preparation

The treatment of carious lesions is the primary objective of tooth preparation and carious tissue excision. All carious lesions were previously treated invasively, or with cutting or drilling, and restoratively, or with the installation of restorative material following preparation and the elimination of carious lesion. Over-reduction simplifies laboratory work and provides for the best aesthetics and durability of the restoration, however there are clear drawbacks, including injury to the dental pulp and lessens retaining abilities and remaining resilience of the tooth. It is crucial to select the most practical entry route, which might be the labial, lingual, or purely proximal technique, in the event that a caries disease is situated on the proximal surface without compromising the enamel on the labial or lingual sides. It is not mandatory to expand the tooth preparation towards to the occlusal grooves when the disease is contained to the proximal surface since doing so will needlessly damage the tooth and make it more brittle. Whenever it is feasible, the proximal approach should be used since this encourages the maximal conservation of the quality remnant tooth structure. The decayed tissue must be eliminated while retaining the greatest amount of the natural tooth structure left upon obtaining entry to the area. The only tooth preparation required is the minimally invasive excision of carious tissue.