# Identification of threshold concepts in the undergraduate orthodontics curriculum: a modified Delphi study

## TL;DR

This study identifies key challenging concepts in undergraduate orthodontics and proposes teaching and assessment strategies to improve learning and curriculum design.

## Contribution

The study provides a novel framework of threshold concepts and strategies for undergraduate orthodontic education through expert consensus.

## Key findings

- 34 out of 39 threshold concepts reached consensus among experts.
- Teaching and assessment strategies were identified for nine domains of orthodontics.
- The framework can help transform students from novices to experts in orthodontics.

## Abstract

Orthodontics is acknowledged as an integral clinical subspecialty in undergraduate dental programs. Mastering such an extensive and multifaceted theoretical knowledge and its implementation into practice is challenging. The student experiences tension, difficulty and frequently lacks preparedness and confidence when performing different orthodontic procedures. Threshold concepts (TCs) can offer a potential solution to this problem. The transforming nature of threshold concepts can significantly influence student learning and curriculum development. A number of learning theories resonate with the concept of TCs. The study aimed to explore TCs and associated teaching strategies (TS) and assessment strategies (AS) in the undergraduate orthodontic curriculum through expert consensus, offering reforms in dental education.

Phase 1 of the study comprised a thorough literature review followed by a preliminary online session with experts to outline the curriculum and assess their understanding of TCs. Two orientation sessions for participants and three FGDs were conducted in two different institutes of twin cities in Pakistan. Qualitative analysis of data was done to formulate questionnaire for Modified Delphi Round 1. In phase 2, the Modified Delphi technique was used to obtain consensus on 39 proposed TCs, their 26 teaching and 26 assessment strategies under nine domains of orthodontics. 41 experts with postgraduate degrees in orthodontics and a minimum of 2 years of teaching experience in the field participated in round 1, 38 in round 2 and 35 in round 3. Prior termination criteria were set with 3 Delphi rounds, ≥80% agreement and stability. Items with ≥80% agreement and stability of responses between two consecutive rounds reached consensus.

34 out of 39 TCs reached consensus. 5 TS and 4 AS were identified for (domains I and II) patient assessment. Similarly, 2 TS and 4 AS for growth and development (domain III), 6 TS and 5 AS for diagnosis (domains IV & V), 6 TS and 5 AS for treatment of orthodontic patients (domains VI, VII & VIII), 3 TS and 1 AS for recent advances (domain IX) reached consensus.

The identified TCs have highlighted specific areas in orthodontics that may pose challenges for students and prevent learning. Due consideration to these TCs and appropriate TS and AS can transform students from novices to experts. The study offered a comprehensive TC framework that can guide undergraduate orthodontic curriculum and practices.

The online version contains supplementary material available at 10.1186/s12909-025-08516-6.