TADs in Orthopaedic Orthodontics – holy grale or hype?
Skeletal vs. Conventional Anchorage in Dentofacial Orthopedics: A Delphi Consensus Study
Introduction: The Debate Over Anchorage in Orthodontics
Anchorage control has long been a cornerstone of orthodontic treatment, particularly in cases of dentofacial orthopedic correction. Over the last 40 years, skeletal anchorage using temporary anchorage devices (TADs) such as miniscrews and miniplates—has emerged as a means to enhance skeletal changes while minimizing unwanted dental side effects. However, despite widespread adoption, the comparative effectiveness of skeletal versus conventional anchorage remains a topic of debate.
The study by Franchi et al. (2025) attempts to bridge this gap by employing a modified Delphi consensus method to gather expert opinions on the use of skeletal anchorage in three key clinical scenarios:
1. Maxillary transverse deficiency in growing and adult patients
2. Class II skeletal disharmony due to mandibular retrusion in growing patients
3. Class III skeletal disharmony in growing patients.
While expert consensus can provide valuable guidance, it must be viewed as an adjunct to empirical clinical evidence. Let’s take a closer look at the methodology and key findings of this consensus study.
Study Design: A Structured Expert Consensus
The study utilized a four-round modified Delphi method, a structured process that gathers expert opinions iteratively to develop consensus. A steering committee composed of experienced orthodontic researchers first conducted a literature review and formulated 33 key statements regarding skeletal versus conventional anchorage. These statements were then reviewed by 25 international experts, each providing their level of agreement on a 5-point Likert scale. Statements that failed to reach consensus were revised or rejected.
After four rounds, 24 statements achieved consensus, while 9 were rejected, highlighting areas of both agreement and continued uncertainty.
Key Findings: Where Experts Agree (and Disagree)
1. Maxillary Transverse Deficiency: Skeletal vs. Conventional Expansion
• Bone-borne expanders reduce unwanted dental effects: Experts agreed that skeletal expanders reduce the buccal tipping of posterior teeth compared to conventional tooth-borne expanders.
• Success decreases with age: Skeletal expanders were deemed effective in late adolescents and adults, but with reduced success rates after age 25 – 30.
•Unpredictability in older patients: While effective, experts noted that skeletal expanders cannot reliably predict midpalatal suture opening in patients over 30.
Lack of Consensus: Experts did not agree on whether bone-anchored expanders provide more stable long-term outcomes or significantly reduce gingival recession risk.
Clinical Takeaway: For young patients, skeletal anchorage can improve expansion without adverse dental effects. However, in adults, results are less predictable, necessitating individualized treatment planning.
2. Class II Skeletal Disharmony: Does Skeletal Anchorage Improve Mandibular Advancement?
• Greater skeletal effects, but limited evidence: Panelists agreed that fixed functional appliances (FFAs) anchored to the lower jaw provide greater sagittal skeletal correction and better control of lower incisor proclination compared to conventional FFAs.
• No superior mandibular rotation control: Contrary to some expectations, skeletal anchorage did not offer superior control of mandibular clockwise rotation.
• Miniscrews vs. Miniplates: Given their less invasive nature, miniscrews were preferred over miniplates for skeletal anchorage in Class II correction.
• Patient acceptance: Skeletal anchorage devices were noted to have lower patient acceptance due to their invasive nature.
Lack of Consensus: No agreement was reached on whether skeletal FFAs offer superior effects compared to removable functional appliances, reflecting ongoing debate.
Clinical Takeaway: Skeletal anchorage may enhance mandibular growth effects, particularly for controlling incisor inclination. However, its clinical impact remains debated, and patient comfort should be a key consideration.
3. Class III Skeletal Disharmony: Is Skeletal Protraction Superior?
• Better dentoalveolar control: Skeletal anchorage significantly reduces undesirable dental movements compared to conventional facemask therapy.
• Greater maxillary protraction, but limited clinical impact: Bone-anchored devices produce larger sagittal skeletal changes, though the magnitude of these changes may not be clinically relevant.
• Alt-RAMEC protocol gains support: Skeletally-anchored maxillary expansion using Alt-RAMEC (Alternating Rapid Maxillary Expansion and Constriction) was considered more effective, particularly in pubertal patients.
• Surgical considerations: The invasiveness and economic cost of skeletal anchorage were justified only in pubertal patients, not in younger children.
• Infection risk: When miniplates emerge through non-keratinized tissue, the risk of inflammation and failure increases.
Lack of Consensus: Experts disagreed on whether Bone-Anchored Maxillary Protraction (BAMP), a fully intraoral alternative to facemask therapy, justifies its invasive surgical approach.
Clinical Takeaway: Skeletal anchorage enhances maxillary protraction, particularly in pubertal patients, but its additional invasiveness should be weighed carefully.
Critical Evaluation: Strengths and Limitations
Strengths
• High-level expert participation: The study included 25 globally recognized orthodontists, ensuring a broad and authoritative consensus.
• Well-structured methodology: The Delphi method systematically refined statements, leading to well-considered conclusions.
• Clinical relevance: The study provides pragmatic guidance for orthodontists facing real-world treatment decisions.
Limitations
• Consensus is not clinical proof: The Delphi method reflects expert opinion, not direct clinical evidence. While valuable, these findings require further validation through randomized controlled trials (RCTs).
• Limited long-term data: The study does not resolve the question of long-term stability for skeletal anchorage techniques.
• Patient factors not fully addressed: While patient acceptance was acknowledged, more research is needed to assess patient-reported outcomes, including comfort and compliance.
Final Thoughts: Where Do We Go from Here?
This Delphi consensus study provides an insightful look into expert opinions on skeletal anchorage in orthodontics.
While skeletal anchorage clearly reduces undesirable dentoalveolar effects, its superiority over conventional anchorage in producing skeletal changes remains uncertain. Moreover, invasiveness, cost, and patient acceptance remain crucial limiting factors.
Ultimately, the decision to use skeletal anchorage should be patient-specific, taking into account age, malocclusion severity, compliance, and willingness to undergo minor surgical procedures. Future high-quality RCTs will be essential to confirm these findings and refine treatment protocols.
Reference:
Franchi L, et al. Skeletal versus Conventional Anchorage in Dentofacial Orthopedics: An International Modified Delphi Consensus Study. Progress in Orthodontics (2025) 26:9.