Mixed Dentition Analysis: Is Advanced Imaging Worth the Cost?
"Cone-beam computed tomography (CBCT) offers precision in assessing developing teeth, but does it outweigh traditional methods and added expense?"
Achieving a harmonious balance between tooth size and jaw dimensions is a cornerstone of successful orthodontic treatment. Malocclusions often stem from discrepancies between these factors. The mixed dentition phase, a period where both primary and permanent teeth coexist, presents unique challenges in assessing potential crowding and developing a comprehensive treatment plan.
During this transitional period, slight crowding in the lower arch is often considered normal as the erupting permanent lateral incisors require additional space. However, accurately predicting the size of unerupted permanent teeth becomes crucial to determine whether the dental arch can accommodate them without significant crowding or the need for extensive intervention.
Traditional methods for mixed dentition analysis include clinical examination, study models, and radiographic assessments. While these techniques have served orthodontists for decades, the advent of cone-beam computed tomography (CBCT) has opened new avenues for visualizing and measuring dental structures with greater precision. This article delves into a study comparing CBCT with traditional methods, evaluating the accuracy, advantages, and limitations of each approach.
Evidence and Emerging Tools
A comparative evaluation reported a highly statistically significant difference in Moyer's mixed dentition analysis between CBCT-derived images and plaster models. New research is addressing pediatric CBCT segmentation through a three-stage framework involving global segmentation, per-tooth refinement, and dentition aggregation. The ToothFairy2 initiative further provides CBCT data, 3D annotations, baseline models, and evaluation code as a benchmark for automated maxillofacial segmentation.
Conventional Methods and Constraints
The American Academy of Oral and Maxillofacial Radiology position statement concluded that there was no clear evidence supporting routine ionizing radiation for standard orthodontic diagnosis and treatment planning, including CBCT. A 2017 comparative evaluation reported that CBCT-derived images were less reliable than measurements obtained directly from plaster models for mixed dentition analysis. These findings frame CBCT as a potentially useful but non-routine option whose accuracy and justification must be weighed against conventional methods.
CBCT vs. Traditional Radiography: A Comparative Look at Mixed Dentition Analysis
The study featured in the Dental Press Journal of Orthodontics aimed to evaluate the effectiveness of CBCT in assessing the size of intra-osseous teeth during the mixed dentition phase. The researchers compared CBCT measurements with those obtained using traditional methods, including:
- Moyers’ Analysis: A prediction table based on the mesiodistal width of erupted lower incisors to estimate the size of unerupted canines and premolars.
- Tanaka-Johnston Formula: A similar predictive method that uses a formula instead of a table.
- 45-Degree Oblique Radiographs: A radiographic technique used to visualize unerupted teeth and measure their dimensions.
- Plaster Cast Models: Measurements of erupted incisors were taken on plaster models using digital calipers.
- CBCT Scans: The same dental units were gauged by means of Dolphin software resources.
- Statistical Analysis: High agreement was observed between tomographic and radiographic methods.
- Low Agreement: Between tomographs and other methods being evaluated.
Evidence-Based Patient Selection
The American Dental Association and American Academy of Oral and Maxillofacial Radiology developed clinical recommendations for selecting patients for dental radiography and CBCT. Because the available evidence has limitations, the authors developed consensus recommendations rather than formal guidelines. This emphasizes individualized imaging decisions rather than automatic CBCT use for every mixed dentition assessment.
Costs and Study Limitations
A systematic review and meta-analysis identified high-cost technology as a disadvantage of digital models, along with security, privacy, and electronic information-loss risks. A preliminary study of digital mixed dentition space analysis used a very small sample and one reference model. Its stated aims included comparing optical-impression digital models with conventional plaster analysis and assessing differences between examiners, so its findings require cautious interpretation.
The Verdict: Is CBCT the Future of Mixed Dentition Analysis?
While CBCT offers several advantages, including the ability to visualize intra-osseous teeth individually and without superimposition of anatomical structures, it is essential to consider the limitations and costs associated with this technology. CBCT scans expose patients to higher radiation doses than traditional radiographs, and the cost of CBCT equipment and software can be significant. Ultimately, the decision to use CBCT for mixed dentition analysis should be based on a careful assessment of the individual patient's needs, the complexity of the case, and the available resources.
AI and Portable CBCT
A 2026 CBCT trends report identifies technological innovation, digital workflows, and demand for advanced dental diagnostics as drivers of continued market growth. It highlights artificial intelligence and low-dose, portable systems as critical trends shaping the market's future. Another 2026 industry source similarly describes CBCT's future in digital dentistry as driven by ongoing innovation and an emphasis on patient outcomes.
Clinical Applications in Children
A 2024 study developed a deep-learning approach for precise classification and three-dimensional segmentation of mixed dentition in CBCT scans. The study identified dentofacial deformities, supernumerary teeth, and metal artifacts as challenges, while reporting potential improvements in diagnostic accuracy and efficacy. Separately, a retrospective study evaluated a customized elastodontic appliance in 31 mixed dentition children with a mean age of 8.3 ± 1.2 years, using CBCT to examine whether expansion effects were dental, dentoalveolar, or skeletal.