Evolving Trends and Emerging Frontiers in Clear Aligner Therapy: A Bibliometric and Social Impact Analysis (2015-2024)

Abstract

Introduction and aims

Clear aligner therapy (CAT) serves as an innovative alternative to traditional fixed appliances, gaining rapid clinical adoption in recent years due to its superior aesthetics, treatment efficiency, patient comfort, and ease of use, which has driven explosive growth in related research. This bibliometric analysis aims to reveal research focuses and development trends in the CAT field.

Methods

Articles related to CAT from 2015 to 2024 were retrieved from the Web of Science Core Collection database using a specific topic query, yielding 999 records, with 973 high-quality articles and reviews included after screening. Bibliometric analysis was performed using VOSviewer and Bibliometrix software, including collaboration networks, keyword co-occurrence analysis, and extraction of data on publication years, authors, institutions, countries, journals, keywords, and citations.

Results

From 2015 to 2024, a total of 973 publications in the CAT field were identified, showing exponential growth overall. The American Journal of Orthodontics and Dentofacial Orthopaedics ranked first with 90 articles. The study by Rossini G (2015, Angle Orthod) emerged as the most influential with the highest total citations (421) and annual citations (38.27). The 3 articles with high societal impact were those by Weir, Ke, and Azaripour. The keyword "Invisalign" (n = 232) appeared most frequently. China led in publication volume (n = 221, 22.7%), with the closest collaborations among China, the United States, and Italy. Sichuan University had the highest publication count (n = 109), Weir Tony was the most productive author (n = 26), and Castroflorio Tommaso had the highest total citations (TC = 1045) and local citations (LC = 677).

Conclusion

This analysis offers a comprehensive overview and in-depth examination of future development trends and potential research directions in CAT, which can inspire both clinical and scientific researchers.

Clinical relevance

CAT demonstrates advantages in treatment efficacy, patient comfort, and oral health-related quality of life. The integration of digital workflows, including AI-assisted planning and 3D printing, enhances treatment precision and monitoring. Addressing challenges such as patient compliance and public perception is essential for optimising individualised treatment plans and expanding clinical adoption.

Introduction

As an innovative alternative to traditional fixed appliances, clear aligner therapy (CAT) has achieved rapid clinical adoption in recent years owing to its superior aesthetics, treatment efficiency, patient comfort, and ease of use.^1,2 driving an explosive growth in CAT-related research.³ Bibliometric analysis, widely recognised as an effective method for literature mining in academia, has been extensively applied in oral medicine4, 5, 6, 7 encompassing subfields such as implantology, periodontology, and orthodontics,⁸ and playing an irreplaceable role in systematically delineating disciplinary trajectories, pinpointing research hotspots, and identifying emerging frontiers.⁹

Although bibliometric studies in the CAT domain remain limited in number, they have provided valuable scholarly references for the field. In 2021, the American Journal of Orthodontics and Dentofacial Orthopaedics (AJODO) published the first bibliometric analysis in CAT, systematically identifying emerging research directions with significant potential value; however, given the explosive surge in clear aligner literature after 2020 and the study's early publication time, its conclusions failed to fully reflect the latest developments.³ In 2023, Gong et al. extended the temporal scope to 2002 to 2022, incorporating 613 publications, which not only confirmed a marked upward trend in research output but also offered critical insights for identifying core literature.¹⁰ In 2024, He et al. further expanded the sample to 1031 articles spanning 2003 to 2023, employing more timely inclusion criteria and analytical approaches to delineate emerging areas such as patient perceptions and digital technology applications.¹¹ In 2025, Grassia et al. focused on 50 highly cited articles from 2013 to 2023, elucidating key journal distributions, core author networks, and the evolution of pivotal research themes.¹² These studies have laid a solid foundation for constructing a bibliometric framework in CAT, yet notable limitations persist: restricted coverage, particularly lacking refined temporal segmentation, and an absence of quantitative assessments of literature's societal impact, underscoring the need for expanded scope to provide systematic supplementation and updates.

To address these gaps, the present study aims to: (1) Systematically review 973 high-quality CAT publications from 2015 to 2024, extracting their scholarly characteristics and distribution patterns; (2) Innovatively develop a way to quantify the societal impact of CAT literature (an unexplored aspect previously) and examine the phased changes in publication volume; (3) Precisely capture current research hotspots while forecasting future trends and core challenges in the CAT domain.

Materials and methods

In this bibliometric analysis, we selected the Web of Science Core Collection as the primary data source. The search was conducted using the following query in the Topic (TS) field: TS=(("clear align*" OR "invisible orthodontic appliance*" OR "Invisalign*" OR "transparent align*" OR "customised orthodontic appliance*") AND ("orthodontics" OR "dental alignment" OR "tooth movement" OR "malocclusion" OR "orthodontic treatment" OR "mandibular advancement" OR "functional appliance" OR "torque control" OR "thermoplastic")). This query was designed to comprehensively encompass literature pertaining to clear aligners and related orthodontic topics.

The retrieval period was restricted to January 1, 2015, through December 31, 2024. Initially, 999 records were retrieved from the Web of Science Core Collection database, with no duplicates or ineligible entries identified. To ensure data quality and relevance, we employed automated tools for further screening, including only "Article" and "Review Article" document types while excluding all "Retracted Publication", "Editorial Material", "Proceeding Paper", "Letter", "Correction", and "News Item" entries. This process eliminated 26 records, yielding 973 articles; no additional articles were missed during retrieval. Subsequently, 2 researchers independently reviewed the titles and abstracts of eligible publications for confirmation, with a third researcher providing an independent assessment in cases of disagreement. Ultimately, no further exclusions were made, and all 973 articles met the inclusion criteria. To validate the accuracy of these results, an independent researcher cross-verified and screened them using PubMed, confirming the inclusion of 973 publications in this review (Fig. 1)

Fig. 1.

Flow diagram of data retrieval and filtration of Web of Science Core Collection.

The retrieved results were exported from Web of Science in “Full Record and Cited References” format and saved as "Plain Text" files. These data were then imported into VOSviewer 1.6.15 software, primarily utilising Visualisation of Similarities technology (Centre for Science and Technology Studies, Leiden University, Netherlands) (www.vosviewer.com) (van Eck & Waltman 2010), and Bibliometrix for performing bibliometric analysis and constructing data matrices for co-citation, coupling, scientific collaboration, and co-word analyses.

We subsequently compiled data on publication years, authors, institutions, countries, journals, keywords, and citation counts for these articles. During keyword screening, 2 researchers merged terms with redundant meanings and removed nonsignificant entries; in instances of discordance, a third researcher conducted an independent evaluation to reach a consensus. The final compiled results are detailed in the supplementary materials. Microsoft Office (2021) was used for tabulation and analysis, while VOSviewer and Bibliometrix facilitated visualisation, with a focus on collaboration networks among authors, institutions, and countries, as well as keyword co-occurrence networks. For the author collaboration network, a Document × Author matrix was constructed using the cocMatrix function, and the biblioNetwork function was employed to generate the network. For the institution collaboration network, institutional affiliations were first extracted via the metaTagExtraction function, followed by construction of a Document × Institution matrix with cocMatrix and network generation using biblioNetwork. For the country collaboration network, country information was extracted from author affiliations using metaTagExtraction, a Document × Country matrix was computed with cocMatrix, and the network was built via biblioNetwork.¹³ Notably, the country collaboration network was visualised as a chord diagram using RAWGraphs, where the thickness of connecting lines between countries is proportional to collaboration frequency, and the area occupied by each country represents its collaborative influence. In other collaboration networks, line thickness indicates collaboration intensity, while node size reflects the volume and impact of collaborative publications. For keywords, networks based on co-occurrence relationships were constructed to illustrate inter-keyword associations. In Bibliometrix, a Document × Word matrix was calculated using cocMatrix (this study utilised Keywords Plus, which are automatically generated index terms by the Web of Science database via the R package Bibliometrix, derived from frequently occurring words in referenced titles; this enhances traditional keyword or title searches. To mitigate redundancy, authors manually reviewed and revised all terms), enabling the creation of keyword co-occurrence networks.¹³ Node size denotes keyword frequency, node color indicates cluster membership, and edge thickness between nodes represents the frequency of co-occurrence in the same article.

Visualisation and graphing were performed using RAWGraphs, RStudio, and Excel, including rankings of journals and citation counts. Finally, societal impact was assessed using PlumX.¹⁴ Developed by Plum Analytics, PlumX evaluates the societal influence of publications through the following metrics: (1) "PlumX Captures" tracks user engagement via downloads, saves, and bookmarks; (2) "PlumX Mentions" quantifies relevance in society by measuring usage across digital media platforms; (3) "PlumX Social Media" assesses interactions on social media.^14,15 These metrics were obtained by querying relevant articles in Scopus. Given gaps in altmetric indicators, we devised a Social Influence Score (SIS) formula, modeled after the Altmetric Attention Score weighting system, for a comprehensive societal impact evaluation: $\text{SIS}=\mathrm{w}\_\mathrm{C}\times \text{log}\left(1+\mathrm{C}\right)+\mathrm{w}\_\mathrm{M}\times \text{log}\left(1+\mathrm{M}\right)+\mathrm{w}\_\mathrm{S}\times \text{log}\left(1+\mathrm{S}\right)$, where C is total Captures, M is total Mentions, S is total Social Media, w_C = 3 (moderate weight for Captures, as it predicts future impact but is more private), w_M = 5 (highest weight for Mentions, reflecting deep media or public engagement), and w_S = 1 (lowest weight for Social Media, due to its transient and manipulable nature). Common logarithms (log10) were applied to handle zero and extreme values, preventing skew from high S values. Calculated SIS values were categorised as follows: SIS > 50 indicates extremely high societal impact, signifying profound resonance, widespread dissemination, and potential hotspot status; 30 < SIS ≤ 50 denotes high societal impact, with strong online visibility and engagement; 10 < SIS ≤ 30 represents moderate societal impact, typical of active research with limited but positive attention; SIS ≤ 10 signifies low societal impact, with constrained influence and minimal societal interest.

Result

Publication

Between 2015 and 2024, a total of 973 articles in the clear aligner therapy (CAT) domain were published, exhibiting an exponential growth trajectory, rising from 15 articles in 2015 to 300 in 2024, with a compound annual growth rate of 41.4%. The publication output over this decade demonstrates distinct phased evolutionary patterns (Fig. 2). Specifically, 3 periods can be delineated: (1) Slow Accumulation Phase (2015-2019): Annual publication counts fluctuated between 13 and 33 articles, with an abnormally low output of 13 articles in 2017, likely due to technical bottlenecks or adjustments in data collection. This phase represents an exploratory period for the industry, characterised by immature material development (eg, Thermoplastic Polyurethane [TPU] and Polyethylene Terephthalate Glycol [PETG]) and limited clinical validation. (2) Growth Initiation Phase (2020–2021): Publication output surged to 75 articles in 2020 (+127.3% year-on-year) and reached 92 articles in 2021 (+22.7%). This phase aligns with increased demand for home-based healthcare post-COVID-19 and accelerated adoption of digital diagnostic technologies, such as remote 3D modelling. (3) Explosive Expansion Phase (2022–2024): Publication counts soared to 176 articles in 2022 (+91.3%), 215 in 2023 (+22.1%), and surpassed 300 in 2024 (+39.5%). This period reflects the emergence of multidisciplinary research following technological maturation, including AI-assisted treatment planning and innovations in paediatric clear aligners.

Fig. 2.

Trends in publication output for clear aligner literature over the past decade. The x-axis labels years from 2015 to 2024, while the y-axis scales from 0 to 300 articles in increments of 100. The trend line demonstrates a continuous upward trajectory. Notably, a significant surge has been observed since 2020, culminating in a record of 300 articles in 2024, indicating increasing academic interest and rapid development in this field.

Journals

Table 1 presents the top 10 journals ranked by the number of published CAT articles, ranging from 90 to 23 articles. The American Journal of Orthodontics and Dentofacial Orthopaedics (AJODO) leads with 90 articles, followed by The Angle Orthodontist (AO) with 59 articles, and BMC Oral Health with 54 articles, ranking third. In terms of citation counts, the total citations for these top 10 journals range from 2186 to 67, with AO topping the list at 2186 citations, followed by AJODO with 1881 citations, and Progress in Orthodontics with 1433 citations, ranking third.

Table 1.

Top 10 journals publishing clear aligner articles, ranked by article count

Rank	Sources	Articles	Citations	Average Citations	h_index	g_index	m_index
1	AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS	90	1881	20.9	26	41	2.364
2	ANGLE ORTHODONTIST	59	2186	37.05	24	46	2.182
3	BMC ORAL HEALTH	54	653	12.09	12	24	1.091
4	PROGRESS IN ORTHODONTICS	47	1433	30.49	22	37	2
5	APPLIED SCIENCES-BASEL	47	189	4.02	8	11	1.333
6	AUSTRALASIAN ORTHODONTIC JOURNAL	25	67	2.68	4	7	0.667
7	ORTHODONTICS&CRANIOFACIAL RESEARCH	24	521	21.7	8	22	0.889
8	SEMINARS IN ORTHODONTICS	24	221	9.2	7	14	0.778

Based on Bradford’s Law, the 109 journals included in this study were divided into 3 zones. Figure 3 details the journal and article counts across these zones. The core zone comprises 6 journals (corresponding to the top 6 in Table 1), which collectively published 322 articles. The second zone includes 20 journals, contributing 313 articles, while the third zone encompasses 164 journals, accounting for 307 articles.

Fig. 3.

Core sources by Bradford’s Law. The core zone comprises 6 journals contributing 322 articles. The second zone includes 20 journals, contributing 313 articles, while the third zone includes 164 journals, accounting for 307 articles.

The h-index was used to gauge the influence of these journals in the CAT domain, with values ranging from 26 to 4; the top 3 journals achieved h-indices of 26, 24, and 22, respectively. The g-index, assessing the production of highly cited articles, ranged from 46 to 7, with the top 3 journals recording g-indices of 46, 41, and 37. The m-index, reflecting the journals’ annual academic influence in the field, ranged from 2.364 to 0.667, with the top 3 journals achieving m-indices of 2.364, 2.182, and 2.000, respectively (Table 1).

Top 10 cited articles

Table 2 and Figure 4. list the top 10 most-cited articles and the sources ratio in the CAT domain. Among these, Rossini G’s 2015 study in The Angle Orthodontist, titled “Efficacy of clear aligners in controlling orthodontic tooth movement: A systematic review” ranks first with a total of 421 citations and an annual citation rate of 38.27. This is followed by Hao J L’s 2020 study in American Journal of Orthodontics and Dentofacial Orthopaedics, titled “Has Invisalign improved? A prospective follow-up study on the efficacy of tooth movement with Invisalign” with 211 total citations (35.17 annually), and Weir T’s 2017 study in Australian Dental Journal, titled “Clear aligners in orthodontic treatment” with 208 total citations (23.11 annually). The remaining articles range from 175 citations (eg, Papadimitriou A, 2018, Progress in Orthodontics) to 125 citations (eg, Ravera S, 2016, Progress in Orthodontics), with annual citation rates spanning 12.50 to 26.83. Additionally, altmetric data capturing societal impact, including PlumX metrics (Captures, Mentions, and Social Media), were collected. Captures ranged from 345 to 1216, Mentions from 1 to 10, and Social Media interactions showed a wide range (0-436). Notably, societal impact did not consistently correlate with citation counts. The three articles with the highest Social Influence Scores (SIS)—Weir T, Ke YY, and Azaripour A—fell within the moderate to low SIS range (10.53-15.59). The PlumX metrics for each article’s societal impact are presented in Table 2.

Table 2.

The 10 most cited articles on clear aligners therapy (CAT)

Rank	Title	Journal	Author	Year	Total Citations	TC per Year	Captures	Mentions	Social media	SIS
1	Efficacy of clear aligners in controlling orthodontic tooth movement: A systematic review	ANGLE ORTHOD	ROSSINI G	2015	421	38.27	1216	4	\	12.75
2	Has Invisalign improved? A prospective follow-up study on the efficacy of tooth movement with Invisalign	AM J ORTHOD DENTOFAC	HAOUILI N	2020	211	35.17	457	6	\	12.21
3	Clear aligners in orthodontic treatment	AUST DENT J	WEIR T	2017	208	23.11	921	10	30	15.59
4	Clinical effectiveness of Invisalign orthodontic treatment: a systematic review	PROG ORTHOD	PAPADIMITRIOU A	2018	175	21.88	646	1	436	12.57
5	Effectiveness of clear aligner therapy for orthodontic treatment: A systematic review	ORTHOD CRANIOFAC RES	ROBERTSON L	2020	161	26.83	449	4	78	13.35
6	Efficiency, effectiveness and treatment stability of clear aligners: A systematic review and meta-analysis	ORTHOD CRANIOFAC RES	ZHENG M	2017	148	16.44	517	2	\	10.53
7	Braces versus lnvisalign: gingival parameters and patients' satisfaction during treatment: a cross-sectional study	BMC ORAL HEALTH	AZARIPOUR A	2015	141	12.82	516	9	2	13.62
8	A comparison of treatment effectiveness between clear aligner and fixed appliance therapies	BMC ORAL HEALTH	KE YY	2019	137	19.57	653	5	33	13.87
9	Direct 3D Printing of Clear Orthodontic Aligners: Current State and Future Possibilities	MATERIALS	TARTAGLIA GM	2021	127	25.4	456	3	\	10.99
10	Maxillary molar distalisation with aligners in adult patients: a multicentre retrospective study	PROG ORTHOD	RAVERA S	2016	125	12.5	345	3	1	10.93

Fig. 4.

Distribution of journals and countries of origin for the top 10 most-cited articles on clear aligners. The upper pie chart illustrates the geographic origins of the primary research institutions, while the lower pie chart categorises the publication venues. Notably, Italy (28%) and the China (18%) emerge as the leading contributors to high-impact literature in this field. Regarding journals, the distribution is relatively balanced among three key journals: Orthodontics & Craniofacial Research, Progress in Orthodontics, and BMC Oral Health, which collectively account for the majority of the top-cited articles. This pattern indicates that high-impact research in this field is disseminated across a focused group of specialised open-access and traditional journals.

Keywords

Keywords were generated using Web of Science’s Keywords Plus, analysed via the R package Bibliometrix, and manually curated to ensure accuracy.¹³ The top 50 most frequent keywords in the clear aligner therapy (CAT) domain are presented (Table 3, see the end of the text), revealing key research hotspots. “Invisalign” (n = 232) emerged as the most frequent keyword, underscoring its brand dominance, followed closely by “tooth movement” (n = 221) and “efficacy” (n = 169), highlighting the critical focus on orthodontic tooth movement and treatment effectiveness. The keyword co-occurrence network (Fig. 5) categorised keywords into three clusters through clustering analysis: the green cluster centres on clinical efficacy, with core nodes including “Invisalign”, “tooth movement”, and “efficacy”; the red cluster emphasises patient experience and health, featuring keywords such as “quality-of-life”, “periodontal health” and “discomfort”, reflecting a shift in CAT research toward patient-centred outcomes and enhanced quality of life; the blue cluster focuses on technological advancements, with terms like “thermoplastic materials”, “3D printing”, and “material stiffness” gaining prominence, potentially signalling future trends in material optimisation.

Table 3.

Top 50 keywords ranked by frequency of occurrence

Words	Occurrences
Invisalign	232
Tooth movement	221
Efficacy	169
Appliance	120
Clear aligners	114
Orthodontic treatment	109
Accuracy	102
Force	78
Malocclusion	71
Thermoplastic materials	56
Movement	53
Mechanical-properties	45
Therapy	45
Activation	39
Health	38
Efficiency	37
Incisor	34
Orthodontic tooth movement	33
Reliability	32
Material stiffness	31
Stability	29
Adult	28
Attachment	27
Aligner	26
Periodontal health	26
System	26
Anchorage	23
Removable orthodontic appliances	22
Beam computed-tomography	21
Periodontal-ligament	21
Children	20
Overbite	20
Perception	20
Retraction	20
Teeth	20
Discomfort	19
Root resorption	19
Behaviour	18
Pain	18
Quality-of-life	18
Retainers	18
Skeletal	18
Fixed appliances	17
Impact	17
Intrusion	17
Management	17
Maxillary central incisor	17
Initial force	16
Removable aligners	16
Thickness	16

Fig. 5.

Keyword co-occurrence network. Node size represents keyword frequency, node colour indicates cluster membership, and edge thickness reflects the frequency of co-occurrence of 2 keywords in the same article.

Countries

Table 4 and Figure 6 display the top 20 countries by publication output in the CAT domain. China leads with 221 articles (22.7% of total output), followed by Italy (n = 191, 19.6%) and the United States (n = 103, 10.6%). China’s publication volume surged significantly after 2022, surpassing Italy’s annual output from 2023 onward. In terms of citations, Italy’s CAT articles garnered the highest total citations (n = 3528), followed by China (n = 2378) and the United States (n = 1886). Figure 7 illustrates the country collaboration network based on total collaboration frequency, with China, the United States, and Italy exhibiting the closest collaborative ties.

Table 4.

Scientific output by country in the clear aligner domain

Country	Articles	Articles %	SCP	MCP	MCP %
CHINA	221	22.7	185	36	16.3
ITALY	191	19.6	154	37	19.4
USA	103	10.6	76	27	26.2
SAUDI ARABIA	45	4.6	36	9	20
INDIA	40	4.1	29	11	27.5
AUSTRALIA	38	3.9	36	2	5.3
GERMANY	33	3.4	21	12	36.4
CANADA	29	3	18	11	37.9
BRAZIL	25	2.6	20	5	20
KOREA	23	2.4	17	6	26.1
SPAIN	20	2.1	19	1	5
PORTUGAL	14	1.4	12	2	14.3
EGYPT	11	1.1	2	9	81.8
SWITZERLAND	11	1.1	2	9	81.8
THAILAND	9	0.9	7	2	22.2
TURKEY	9	0.9	9	0	0
ROMANIA	8	0.8	8	0	0
JAPAN	7	0.7	5	2	28.6
SYRIA	7	0.7	6	1	14.3
UNITED KINGDOM	7	0.7	5	2	28.6

Fig. 6.

Scientific output and collaboration patterns by country in the clear aligner domain. The horizontal stacked bar chart displays the top 20 most productive countries, ranked by total publication volume. The bars are segmented to differentiate between Single Country Publications (SCP) (blue), representing independent domestic research, and Multiple Country Publications (MCP) (pink), signifying international collaborative efforts. Notably, China occupies the leading position in total output, driven predominantly by domestic research (high SCP ratio). In contrast, nations in Europe and North America (eg, Italy, USA, Germany) exhibit a comparatively higher proportion of MCP, indicating a stronger tendency towards international research networking in these regions.

Fig. 7.

Country collaboration network. Chord diagram of the collaboration network among countries in clear aligner therapy (CAT) research from 2015 to 2024. The thickness of connecting lines reflects collaboration frequency, based on co-authored publications. The area of each country segment indicates its collaborative influence, with China leading and showing strong ties with the USA and Italy.

Institutions

The top 15 most relevant institutions by publication output are listed in Table 5. Sichuan University (China) ranks first with 109 articles. Among these 15 institutions, 5 is from Italy, 4 from China, 2 from the United States, and 1 each from India, Australia, Canada, and New Zealand. Figure 8 illustrates the annual publication trends for institutions in the CAT domain over the past decade. The collaboration network (Fig. 9) encompasses 41 institutions across countries including China, Italy, the United States, India, and Egypt, grouped into 7 distinct clusters.

Table 5.

Top 15 institutions ranked by publication output in the clear aligner domain

Affiliation	Articles	Country
SICHUAN UNIVERSITY	109	China
AIR FORCE MILITARY MEDICAL UNIVERSITY	57	China
UNIVERSITY OF TURIN	44	Italy
UNIVERSITY OF FERRARA	39	Italy
PEKING UNIVERSITY	36	China
UNIVERSITY OF L'AQUILA	36	Italy
WUHAN UNIVERSITY	36	China
UNIVERSITY SYSTEM OF OHIO	35	USA
SAVEETHA DENTAL COLLEGE AND HOSPITAL	32	India
UNIVERSITY OF ALBERTA	32	Canada
UNIVERSITY OF ROME TOR VERGATA	30	Italy
VIRGINIA COMMONWEALTH UNIVERSITY	30	USA
UNIVERSITY OF ADELAIDE	29	Australia
A.O.U. CITTA DELLA SALUTE E DELLA SCIENZA DI TORINO	28	Italy
UNIVERSITY OF OTAGO	26	New Zealand

Fig. 8.

Annual research output dynamics of the top-performing affiliations. The graph illustrates the growth patterns of the 7 most productive institutions from 2015 to 2024. A general trend of increasing activity is evident across all listed affiliations. However, a marked divergence is observed in recent years, with Sichuan University showing an exponential growth rate, establishing a clear lead over other prominent centres such as Seoul National University and Capital Medical University.

Fig. 9.

Institution collaboration network. Network of institution collaborations in CAT research from 2015 to 2024. Node size reflects publication volume and impact. Line thickness indicates collaboration intensity. Colours denote cluster patterns.

Authors

Table 6 lists the top 10 most prolific authors from 2015 to 2024 (ranked by article count, with higher Author Fractionalised (AF) scores prioritised for ties), all of whom are highly active in the field and identified as core authors based on Price’s Law (M = 3.8). The most productive author is Weir Tony (Australia, n = 26), followed by Castroflorio Tommaso and Lombardo Luca (both Italy, n = 25 each).

Table 6.

Top 10 authors ranked by publication output in the clear aligner domain

Authors	Articles	Articles Fractionalised
WEIR T	26	8.58
CASTROFLORIO T	25	4.13
LOMBARDO L	25	5.44
MEADE MJ	19	6.68
DEREGIBUS A	18	2.87
LAI WL	17	2.27
LONG H	17	2.27
MEI L	16	2.81
D'ANTO V	15	2.39
COZZA P	14	2.71

Table 7 details the total citations (TC), local citations (LC), and the starting year of domain-related publications for authors. Castroflorio Tommaso leads with the highest TC (1045) and LC (677), followed by Deregibus A (TC = 931, LC = 612), Rossini G (TC = 663, LC = 453), and Parrini S (TC = 662, LC = 451).

Table 7.

Top 10 authors ranked by total citations of clear aligner publications

Author	TC	LC	PY start
CASTROFLORIO T	1045	669	≤2015
DEREGIBUS A	931	612	≤2015
ROSSINI G	663	453	≤2015
PARRINI S	662	451	≤2015
LOMBARDO L	467	269	≤2015
WEIR T	463	283	2017
VAID NR	434	270	2018
SICILIANI G	427	247	≤2015
DEBERNARDI CL	421	302	≤2015
ELIADEST T	414	206	≤2015

The author collaboration network (Fig. 10) includes 45 authors with collaborative ties, organised into 11 distinct clusters.

Fig. 10.

Author collaboration network. Network of co-authorship in CAT research from 2015 to 2024. Node size reflects publication volume and impact, highlighting Weir Tony (n = 26) and Castroflorio Tommaso (TC = 1045, LC = 677). Line thickness shows collaboration strength, with colours indicating author clusters.

Discussion

Publication

This study reveals an exponential increase in clear aligner therapy (CAT) literature over the past decade, reflecting the field’s rapid development and growing academic attention. The phased evolution of CAT research can be categorised into three distinct periods: slow accumulation (2015–2019), growth initiation (2020–2021), and explosive expansion (2022–2024).

During the slow accumulation phase, research primarily focused on material development and clinical validation. In material science, Alexandropoulos et al.¹⁶ and Iijima et al.¹⁷ investigated the mechanical properties and thermal cycling stability of thermoplastic materials such as TPU and PETG, highlighting the need for further material optimisation. Lombardo et al. (2017)¹⁸ and Ma et al.¹⁹ explored material blending ratios and modifications to enhance performance. On the clinical front, Papageorgiou et al.²⁰ reported minimal impact of CAT on oral microbiota, while Gu et al.²¹ noted room for improvement in treatment efficiency and stability. These studies indicate an early emphasis on safety, efficacy, and patient experience.

The growth initiation phase saw a shift toward remote monitoring, 3D modelling, and digitally customised aligners. Tartaglia et al.²² demonstrated the feasibility and enhanced precision of 3D-printed CAT, while Maspero et al.²³ highlighted how remote orthodontics improved patient convenience and reduced anxiety. These findings underscore the role of advancing digital diagnostics and post-COVID-19 demand for home-based care in driving rapid CAT research expansion during this period.

The explosive expansion phase marked a pivot toward interdisciplinary approaches, applications in specific populations, and AI-assisted diagnostics. CAT demonstrated efficacy and compliance advantages in mixed dentition and paediatric orthodontics, as evidenced by Levrini et al.,²⁴ Lione and Lombardo et al.,^25,26 and Kim et al.,²⁷ who reported successful outcomes in arch expansion, periodontal health improvement, and posterior tooth rotation control. Lu et al.²⁸ compared CAT with rapid maxillary expansion (RME), confirming its applicability for mild-to-moderate transverse discrepancies, thus broadening its use in paediatric cases. Adolescent CAT research also surged, with studies indicating superior oral health-related quality of life (OHRQoL) scores in functional, emotional, and social domains compared to traditional appliances.²⁹ In AI-assisted CAT, recent reviews highlight its integration into tooth segmentation, model registration, digital setups, and remote monitoring, significantly enhancing efficiency and precision.³⁰ These advancements reflect CAT’s ongoing evolution, driven by rising aesthetic and comfort demands among younger patients and the incorporation of emerging technologies like AI.

Journal

Over the past decade, an increasing number of interdisciplinary journals outside the oral health domain have published CAT-related research, suggesting that the development of clear aligners heavily relies on progress in fields such as materials science and computer science.

From a journal distribution perspective, Bradford’s Law³¹ categorised the 973 articles into three zones: the core zone, comprising 6 journals, with American Journal of Orthodontics and Dentofacial Orthopaedics (AJODO) accounting for nearly 10% of publications and The Angle Orthodontist leading in citations; the second zone, with 20 journals, bridges the highly specialised core journals and peripheral sources, playing a critical role in disseminating diverse CAT research spanning clinical applications to material science; and the third zone, encompassing 164 journals contributing 307 articles, reflects the broad and diverse sources contributing to CAT literature. While individual publication counts in this zone are lower, collectively, these journals enhance the field’s breadth and depth. This distribution underscores the dominance of a few core journals (eg, AJODO, The Angle Orthodontist) in shaping discourse, while also highlighting the potential of emerging journals.

Further index analysis strengthens journal impact assessments. The h-index, balancing publication quantity and citation frequency, provides a robust measure of sustained influence without overemphasis on outliers.³² AJODO (h-index = 26) leads, indicating a substantial portfolio of consistently impactful “core papers”, followed by The Angle Orthodontist (h-index = 24) and Progress in Orthodontics (h-index = 22), reflecting stable academic contributions. The g-index, which prioritises highly cited “star” papers, highlights breakthrough research.³³ The Angle Orthodontist (g-index = 46) and AJODO (g-index = 41) excel in producing highly cited works, amplifying their influence through seminal CAT studies. The m-index, assessing immediate impact growth,³⁴ positions AJODO (m-index = 2.364) as a leader in rapidly rising visibility within the CAT domain.

Analysis of the top 10 most-cited articles reveals their pivotal role in shaping CAT understanding. Rossini G’s 2015 study³⁵ on the efficacy of clear aligners in controlling tooth movement laid a foundational cornerstone for clinical practice, with its high citation count reflecting the field’s reliance on foundational efficacy research. More recent studies, such as Haouli N’s 2020 work (35.17 citations/year),³⁶ underscore ongoing interest in evaluating Invisalign’s tooth movement efficacy, highlighting dynamic clinical advancements. The diversity of sources and authors in the top 10, spanning clinical efficacy (eg, Weir T, 2017, 23.11 citations/year)³⁷ and systematic reviews (eg, Robertson L, 2020, 26.83 citations/year)³⁷ reflects multidisciplinary engagement driving comprehensive exploration of CAT’s efficiency, stability, and patient satisfaction.

However, the predominance of review articles over experimental studies among these high-impact works suggests that reviews, by their nature, attract more citations, but it also points to challenges in conducting experimental CAT research due to time, cost, and ethical constraints. Notably, as of 2020, Rossini G’s study³⁵ had only 83 citations and Azaripour A’s³⁸ had 33, yet both saw a 4 to 6-fold citation surge by 2024, indicating sustained and growing impact. Geographic analysis of corresponding authors’ addresses for these top 10 articles (Fig. 3) reveals a striking concentration in Western Europe, particularly Italy and China, with sparse representation elsewhere, highlighting regional disparities in research output.

Countries, Institutions, and Authors

In scientific production (Fig. 6), China leads with the highest output and single-country publication percentage (SCP%), excelling in domestic collaboration. Italy ranks second, with the highest multi-country publication percentage (MCP%), reflecting strong international collaboration. Among 48 collaborating countries in the collaboration network (Fig. 7), China, the United States, and Italy exhibit the most robust partnerships, with China–U.S. ties being particularly strong, indicative of regional resource complementarity and globalised trends.

Sichuan University (China) ranks first among institutions for publication output. The top 15 institutions are dominated by Italy (5), China (4), and the United States (2), aligning with national output trends. Temporally (Fig. 8), early contributions were led by Italy’s University of Turin, with Sichuan University emerging prominently later. The institutional collaboration network (Fig. 9) highlights Saveetha Dental College and Hospital, Sichuan University, and University of L’Aquila as highly collaborative, with most partnerships being domestic. The strongest institutional tie stands for the collaboration between the University of Turin and A.O.U. Città della Salute e della Scienza di Torino.

Among authors, Castroflorio T (Italy) published 25 articles over the decade, with 1045 total citations and 669 local citations, establishing him as a core expert with significant influence. Eight of the top 10 authors (Table 6) began publishing in the field before 2015, contributing to its foundational phase, while Weir T and Vaid NR, despite later entry, made substantial impacts. The author collaboration network (Fig. 10) identifies Castroflorio T, Deregibus A, Weir T, and Lombardo L as the most collaborative, with Castroflorio T and Deregibus A (both University of Turin) exhibiting the strongest linkage, underscoring the role of team synergy in advancing CAT’s clinical and theoretical breakthroughs.

Social impact

The practical utility, market acceptance, and patient adoption of clear aligners are defining features of the field, yet few studies have assessed their societal impact, and available metrics remain limited. This study employs PlumX metrics (Mentions and Social Media)¹⁴ alongside the top 10 cited articles (Table 2) to evaluate societal impact. Rossini et al.’s³⁵ review (421 citations) garnered only 3 Wikipedia entries and 1 news mention; Weir et al.² received 2 policy citations, 7 Wikipedia entries, 3 news mentions, and a Social Media score of 30; Haouli et al.³⁶ had a Mentions score of 6 (3 news, 2 blogs, 1 Wikipedia); and Papadimitriou et al.³⁹ recorded 1 blog mention and 436 Social Media interactions, though the blog questioned CAT efficacy. Despite their high citation counts, these articles exhibit limited societal impact per SIS values, with data suggesting incomplete capture. News and blogs often question CAT efficacy, despite scientific evidence supporting its effectiveness and potential to supplant fixed appliances. This disconnect between scientific validation and public perception stems from: (1) Compliance challenges: CAT requires 20 to 22 hours of daily wear, and patient-initiated removal can compromise outcomes, leading to dissatisfaction and skepticism⁴⁰; (2) Cost barriers: Treatment costs (∼$3000) may burden uninsured patients, fuelling discontent⁴¹; (3) Media misrepresentation: High-level research targets professionals, while public perception is swayed by media scepticism, favouring cheaper, less aesthetic fixed appliances. Widespread CAT adoption hinges on addressing compliance, cost, and public perception challenges.

Limitations

Despite efforts to minimise bias through careful study design, several limitations persist:

• 1.Incomplete Data Sources: This study relied solely on the Web of Science database, with a cross-check conducted via PubMed to verify data accuracy. However, this approach may still omit gray literature (eg, internal reports, unindexed conference papers), leading to minor data loss. This could make the research sample incomplete, making it difficult to fully reflect the actual distribution of CAT-related studies.
• 2.Metric Shortcomings: Common metrics (eg, h-index, g-index, m-index) can be affected by deliberate self-citations or too many review articles, and thus may not accurately reflect the quality or innovation of a paper.⁴² High citation counts do not always mean high-quality research, and low-cited articles may still have academic value, which may bring bias when evaluating scholars or journals.
• 3.Time-Related Constraints: As an emerging field, clear aligner therapy (CAT) research sees hundreds of new publications annually. Recent articles, due to their short publication history, often lack sufficient citation accumulation to assess long-term impact. The value of influential works may only become evident years later, making short-term analyses less effective in capturing dynamic trends.
• 4.Limited Coverage of Emerging and Interdisciplinary Fields: CAT research involves multiple disciplines, with publications spread across diverse channels and ambiguous keyword definitions. This raises the risk of missing some studies during retrieval and limits our ability to assess developmental trends.
• 5.In the Institution and Country sections, statistics were automatedly extracted based on corresponding author's address which may not fully capture represent multi-centre or multinational collaborations. The result interprets affiliation data as indicative rather than exhaustive of collaborative networks.

Future research should incorporate multiple databases to collect all relevant literature, dynamically track new publications, and introduce novel metrics such as an “interdisciplinary fusion index” (eg, calculating disciplinary entropy of citations to measure source diversity) and “emerging trend indicators” (eg, time-series-based keyword burst detection to identify rapidly growing research directions) to make the analysis deeper and more accurate.

Conclusion

This bibliometric analysis examines the evolution of clear aligner therapy (CAT) research from 2015 to 2024, revealing rapid growth in publication volume and citation counts. The field is predominantly led by contributions from Italy and China, with 2 journals (American Journal of Orthodontics and Dentofacial Orthopedics and The Angle Orthodontist) playing a pivotal role, closely followed by several other influential journals. Review articles dominate the literature, with a notable scarcity of well-designed clinical experimental studies. Research focuses on tooth movement efficacy, material optimisation, and patient quality of life, with advancements closely tied to developments in materials science and computer science. CAT holds the potential to become a cornerstone of orthodontics, possibly surpassing traditional fixed appliances by offering more comfortable and aesthetic treatment options. However, challenges remain, including a disconnect between scientific evidence and public perception, insufficient long-term clinical data, and limited tools for interdisciplinary assessment. Future efforts should prioritise multi-source data integration, development of interdisciplinary fusion metrics, and enhanced public communication to bridge the gap in technology adoption.

Data availability

Data is provided within the manuscript or supplememtary information files.

Funding

This work was supported by the National Natural Science Foundation of China (NSFC-82001083), Project of the Jilin Province Department of Finance (jcsz2025678-16) and Project of the Jilin Province Department of Science and Technology (YDZJ202501ZYTS080).

Author contributions

Wu and Zhang contributed equally to this work. All authors have reviewed the final version to be published and agreed to be accountable for all aspects of the work. Wei, Wu contributed for concept and design; Wu, Zhang, Yu, Jia contributed for study conceptualisation, data analysis, visualisation. Wei, Jia, Wu, Zhang, Yu contributed for drafting of the manuscript; Wei, Jia contributed for supervision.