MARPE and SARPE in orthodontics: past developments, current trends, and future perspectives – a bibliometric analysis

Data collection

The present study was conducted based on bibliometric data obtained from the Scopus database (Elsevier BV, Amsterdam, The Netherlands). Separate search strategies were developed for MARPE and SARPE. The following query was used for MARPE:

TITLE-ABS-KEY(“miniscrew assisted rapid palatal expansion” OR “marpe” OR “microimplant assisted rapid palatal expansion” OR “temporary anchorage device assisted expansion” OR “miniscrew assisted expansion” OR “tad assisted expansion” OR “miniscrew assisted rapid maxillary expansion” OR “microimplant assisted rapid maxillary expansion”) AND (DOCTYPE(ar) OR DOCTYPE(re)).

For SARPE, the query was as follows:

TITLE-ABS-KEY(“surgically assisted rapid palatal expansion” OR “SARPE” OR “surgically assisted expansion” OR “surgical assisted rapid maxillary expansion” OR “sarme” OR “surgically assisted rapid maxillary expansion (sarme)”) AND (LIMIT-TO(DOCTYPE,“ar”) OR LIMIT-TO(DOCTYPE,“re”)).

Only original research and review articles published in English were included, while case reports, letters, editorial articles, and conference abstracts were excluded. The searches were performed on September 15, 2025. The advanced search yielded 283 publications for MARPE and 481 publications for SARPE

Data processing

Two independent researchers (M.S. and A.Y.) screened the articles based on titles and abstracts, and ineligible studies were excluded. The exclusion criteria were: (1) publications unrelated to the topic; (2) opinion articles, editorials, conference reports, and case reports/series; (3) books; and (4) retracted publications. The two researchers achieved a Cohen's kappa agreement score of 0.97, indicating a high level of concordance. Discrepancies in the final selection of certain articles were resolved through evaluation by a third researcher (H.C.). Ultimately, 202 records were included for MARPE and 347 for SARPE (Figure 1).

Figure 1.

Bibliographic data were exported from the Scopus database in CSV, RIS, and BibTeX formats. The exported fields included authors, title, year, source journal, citation count, document type, DOI, abstract, references, key words, and affiliation information.

Data analysis

Bibliometric analyses were performed using the Bibliometrix R-package (version 4.2.1) and VOSviewer (version 1.6.19). For statistical tests and additional visualizations, Python (version 3.10) was utilized with the pandas, scipy, matplotlib, and networkx libraries. Tables were generated from data processed with pandas. Keyword co-occurrence network analysis was conducted using VOSviewer, while other graphs were produced with matplotlib.

To evaluate the relationship between countries' scientific output and economic indicators, per capita gross domestic product (GDP) data were obtained from the World Bank's World Development Indicators database.¹⁵ The associations between GDP and the number of publications, total citations, and average citations per article were analyzed using Pearson correlation analysis. Additionally, simple linear regression was applied to examine trends among variables, with a significance level set at P < 0.05. In addition to the bibliometric metrics, the top-cited articles were qualitatively analyzed to extract key clinical themes and guidelines presented in the discussion section.

Comparison of key metrics

The main metrics of the relevant literature are presented as a radar chart in Figure 2. For MARPE, 202 publications across 67 journals were identified, whereas 347 publications across 110 journals were found for SARPE. In terms of citation performance, SARPE publications exhibited a higher mean number of citations per article (20.16) compared to MARPE (13.53); however, MARPE publications received more citations on an annual basis (2.53 vs. 1.64). Among MARPE publications, 171 were original articles and 31 were reviews, while SARPE included 312 original articles and 35 reviews.

Figure 2.

Annual publication volume analysis

The annual percentage growth rate for MARPE was 38.86%, whereas it was 10.38% for SARPE (Figure 2). Figure 3 illustrates the temporal trends of publications in the SARPE and MARPE fields. SARPE studies followed an ‘S’-shaped trend with a steady increase over the years, while MARPE publications showed a rapid acceleration, particularly in the last five years. Furthermore, when examining the proportion of MARPE publications relative to the total number of MARPE and SARPE publications in a given year (depicted by the blue line), the dramatic rise of MARPE becomes evident. The MARPE-to-total publication ratio exceeded 50% in 2019 and, except for 2020, remained above 50% in subsequent years.

Figure 3.

Authors' analysis

A total of 3,903 authors contributed to the 549 publications in the respective fields (1,484 for MARPE; 2,419 for SARPE). Table I lists the top 10 most cited authors in the MARPE and SARPE domains. In MARPE research, the author with the highest total citations was Moon, Won (834 citations), followed by Lee, Kee-joon (516) and Machado, André Wilson (388). A significant portion of these publications originated from universities in South Korea and Brazil. In the SARPE field, the most cited author was Mommaerts, Maurice Y. (470 citations), with Koudstaal, Maarten Jan (352) and Wolvius, Eppo Bonne (352) sharing the second position. Researchers from the Netherlands and Belgium were particularly prominent in SARPE studies.

Countries' analysis

The top 10 countries in terms of publication output in the MARPE and SARPE fields are shown in Figure 4. For SARPE, Brazil (68), Turkey (53), and Germany (38) had the highest number of publications, whereas for MARPE, the ranking was the United States (34), Brazil (34), and South Korea (33). Although some countries had relatively low publication counts, they demonstrated high average citations per article, notably the Netherlands and Belgium. The United States exhibited high average citations in both MARPE and SARPE domains.

Figure 4.

No significant correlation was observed between the number of publications and countries' per capita gross domestic product (GDP), and the correlation between total citations and GDP was weak. However, a strong and significant correlation was found between average citations per article and GDP (Table II). While countries with middle-to-low GDP, such as Brazil, generated a high number of publications, high-GDP countries like the United States, Belgium, and the Netherlands produced fewer but more highly cited publications.

Journals' analysis

Figure 5 depicts the journals with the highest number of publications in MARPE and SARPE fields over the years. In the MARPE literature, the American Journal of Orthodontics and Dentofacial Orthopedics had the highest number of publications (26), followed by Korean Journal of Orthodontics (15) and Progress in Orthodontics (12). Notably, the publication counts in these three journals increased rapidly after 2020.

Figure 5.

In the SARPE field, the most prolific journals were the International Journal of Oral and Maxillofacial Surgery (38 publications), Journal of Oral and Maxillofacial Surgery (26 publications), and Journal of Cranio-Maxillofacial Surgery (26 publications). Additionally, the orthodontics-focused journal American Journal of Orthodontics and Dentofacial Orthopedics (26 publications) also made a noteworthy contribution.

Citation analysis

Tables III and IV present the most cited articles in the MARPE and SARPE domains. In both fields, a substantial portion of highly cited publications were review articles. In terms of total citations, the most cited SARPE article received 272 citations, whereas the top MARPE article received 175 citations. However, when considering annual citation rates, MARPE publications achieved higher values; for instance, a MARPE article published in 2017 reached the highest annual citation rate of 19.4 citations/year. Furthermore, clinical research articles were more prominent in MARPE, whereas SARPE literature was dominated by review articles.

Keyword analysis

Keywords reflect trends and focal points within a research field.¹⁸ The keyword co-occurrence networks for MARPE and SARPE are shown in Figures 6 and 7. In the MARPE literature, the most central keywords were “palatal expansion” and “palatal expansion technique”, followed by clinical and methodological terms such as “adult”, “adolescent”, “cone beam computed tomography (CBCT)”, and “diagnostic imaging”. The term “miniscrew assisted rapid palatal expansion (MARPE)” was also frequently used as a key word. In the SARPE literature, “palatal expansion” was the primary keyword, but associated terms were more surgically oriented. The most frequently occurring terms included “surgery”, “osteotomy”, “surgical technique”, and “orthognathic surgery”. Demographic descriptors such as “adult”, “male”, and “female” were also frequently employed.

Figure 6.

Figure 7.

Clinical Implications and Evidence-Based Guidelines

Based on the keyword analyses and highly cited studies, the following comparative guidelines emerge to guide clinicians and inspire future researchers:

Re-defining the “Borderline” Patient: The bibliometric data shows a surge in keywords like “young adult” and “skeletal maturation.” (Figure 7). Clinically, this corresponds to the findings of Brunetto et al.¹⁴ who reported a 96.33% success rate in opening the midpalatal suture in patients with a mean age of 26.1 years. Similarly, the systematic review by Kapetanović et al.⁴ confirmed a 92.5% success rate in late adolescents and adults, suggesting that chronological age alone should no longer be viewed as an absolute contraindication for non-surgical expansion. Thus, the “age limit” is not a rigid wall but a gradient that MARPE has significantly extended.

However, beyond chronological age, factors such as circummaxillary suture thickness, midpalatal suture maturation stage, and appliance design are key determinants of the expansion procedure. It has been reported that treatment failures can occur even when all these factors appear favorable.^4,25,26 The central position and recency (red color) of keywords like “adult”, “adolescent”, and “child” in Figure 7 support the complexity of this decision-making process. Consequently, while MARPE is the first line of treatment for young adults, SARPE remains the necessary alternative for cases where high sutural resistance leads to failure or where massive expansion is required.^23,27

Morbidity vs. Predictability Trade-off: SARPE remains the traditional method of choice for skeletally mature patients with massive skeletal discrepancies, due to its consistent ability to enlarge the apical base.²⁸ However, this comes with surgical invasiveness and morbidity. In contrast, the MARPE literature highlights terms like “safety” and “minimally invasive.” The trade-off is clear: MARPE offers a superior patient-reported outcome profile but carries a risk of technical failure (e.g., screw breakage/tipping) that is virtually non-existent in osteotomy-assisted SARPE.²⁹ Furthermore, the prominent clustering of terms like ‘CBCT’ and ‘diagnostic imaging’ in our analysis suggests that the integration of digital planning is increasingly mitigating these technical risks by ensuring precise bicortical engagement.

Periodontal and Airway Outcomes: Both modalities offer advantages over tooth-borne RME. Huang et al. confirmed that MARPE minimizes buccal tipping, a benefit historically attributed only to SARPE.³⁰ Regarding respiratory function, Koudstaal et al.²⁸ established SARPE's efficacy in increasing nasal volume. Interestingly, recent MARPE studies suggest that the bicortical anchorage facilitates a parallel expansion pattern, which some authors posit may yield respiratory benefits comparable to, or potentially even more favorable than, those traditionally associated with SARPE. This suggests that for respiratory indications, the choice may be driven more by patient preference and invasiveness tolerance than by efficacy differences alone.¹⁴

Long-Term Stability and Relapse: While SARPE has established long-term stability data, the “stability” keyword cluster in MARPE research is still maturing.^21,31 However, recent longitudinal studies indicate that the skeletal nature of MARPE expansion—characterized by the parallel separation of the midpalatal suture—offers promising retention outcomes.^4,30 Clinicians should note that while dental relapse (tipping relapse) is common in tooth-borne expanders, the skeletal gain from MARPE appears stable after 1 year of retention.³⁰ Nevertheless, compared to the rigid bony callus formed after SARPE osteotomies, the suture remodeled by MARPE may require prolonged retention periods to prevent skeletal rebound.¹⁴

A strength of our study is the simultaneous examination of two distinct fields, allowing for a comparative evaluation between them. Nevertheless, the study has certain limitations. First, data were retrieved from a single database, which may have resulted in the omission of relevant publications not indexed therein. Additionally, bibliometric analyses inherently rely on quantitative metrics, which may not fully capture the qualitative impact or clinical significance of individual studies. Furthermore, variations in citation practices across disciplines and time periods could introduce bias in citation-based comparisons.