Top 2 Most Influential Orthodontic Articles on PubMed

Reference

Little RM. Stability and relapse of mandibular anterior alignment: University of Washington studies.
Seminars in Orthodontics. 1999;5(3):191-204.
PMID: 10560070

Background

One of the greatest challenges in orthodontics is maintaining treatment results over time. Although excellent dental alignment can usually be achieved during active treatment, long-term stability remains unpredictable. Relapse has been extensively studied, particularly in the mandibular anterior region.

Objective

This landmark study aimed to evaluate the long-term stability of mandibular anterior alignment following orthodontic treatment and to identify factors associated with relapse.

Materials and Methods

Patients treated orthodontically at the University of Washington were followed for many years after treatment completion. Dental casts obtained immediately after treatment and during long-term follow-up were compared to quantify changes in lower incisor alignment.

Results

The study demonstrated that relapse of mandibular incisor alignment is common, even in patients who achieved excellent treatment outcomes.

• Most patients exhibited some degree of lower incisor crowding during long-term follow-up.
• No single pretreatment characteristic reliably predicted long-term stability.
• Growth, aging and individual biological variation contributed to post-treatment changes.
• Perfect alignment at appliance removal did not guarantee permanent stability.

Main Scientific Findings

• Orthodontic relapse is considered a normal biological phenomenon.
• Mandibular anterior crowding may continue throughout adulthood.
• Permanent or prolonged retention significantly improves long-term outcomes.
• Retention protocols should be individualized according to patient risk factors.

Authors' Conclusion

The authors concluded that long-term orthodontic stability cannot be guaranteed. Retention should be viewed as an integral component of orthodontic treatment rather than its final stage, and patients should be informed that physiological changes continue throughout life.

Clinical Relevance for Orthodontists

This publication fundamentally changed orthodontic retention philosophy. Today, many clinicians recommend long-term or even lifelong retention, particularly in the mandibular anterior segment, to minimize relapse. The study remains one of the most influential references supporting evidence-based retention protocols.

Key Takeaways

• ✔ Relapse is common after orthodontic treatment.
• ✔ No treatment technique completely prevents relapse.
• ✔ Long-term retention is essential.
• ✔ Patient education is crucial for maintaining treatment results.

Keywords

Orthodontic relapse; retention; mandibular incisor crowding; long-term stability; orthodontic treatment; evidence-based orthodontics.