Pulp fiction or pulp fact—does orthodontics damage pulpal tissue?

www.nature.com/ebd COMMENT Orthodontics Pulp fiction or pulp fact—does orthodontics damage pulpal tissue? Helen Fegan1 ✉ © The Author(s), under exclusive licence to British Dental Association 2023 1234567890();,: A COMMENTARY ON Jukka Huokuna, Vuokko Loimaranta, Merja A.Laine and AnnaLiisa Svedström-Oristo Adverse effects of orthodontic forces on dental pulp. Appearance and character. A systematic review. Acta Odontol Scand 2022;27:1-11. PRACTICE POINT ● There are no clear signs of permanent pulpal damage to healthy teeth due to the application of orthodontic forces. DATA SOURCES: Electronic databases PubMed, Scopus and Embase were systematically searched and restricted to articles published between February 2009 and 2022. STUDY SELECTION: Studies were categorized using the modified method by the Swedish Council of Technology Assessment in Health Care. 20 studies were included, one of which was categorized as high quality (Grade A) and 19 of which were of moderate quality (Grade B). Exclusion criteria included articles with insufficient descriptions of reliability and reproducibility testing, review articles and case reports, and studies including traumatised teeth. DATA EXTRACTION AND SYNTHESIS: Three independent authors examined titles, abstracts and full texts of relevant articles against the inclusion criteria. Disagreements were resolved by discussion. Retrieved studies were assessed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data extracted included tooth movement performed, the appliance and force used, follow-up of subjects, changes in pulpal blood flow (PBF), tooth sensibility, expression of inflammation-related proteins, along with pulpal histology and morphology changes during tooth movement (intrusion, extrusion and tipping). Overall risk of bias was unclear. RESULTS: A reduction in pulpal blood flow and tooth sensibility due to the application of orthodontic forces was reported by studies included in the review. Increases in the activity of proteins and enzymes related to inflammation of the pulp was reported. Two studies reported histological changes of the pulpal tissues related to orthodontic treatment. CONCLUSIONS: Orthodontic forces cause multiple temporary detectable changes in the dental pulp. The authors conclude there are no clear signs of permanent pulpal damage to healthy teeth due to the application of orthodontic forces. Evidence-Based Dentistry (2023) 24:39–40; https://doi.org/10.1038/s41432-023-00871-x Grade Rating: COMMENTARY In the United Kingdom, the setting in which orthodontic care is provided has changed dramatically during the past few years. With a controversial increase in the popularity of direct-toconsumer orthodontic treatment [1], and more general dental practitioners providing orthodontic treatment than ever before, it is important for practitioners and patients to be aware of the risks of orthodontics in the wider context of the health of the tooth. The authors aimed to review recent data on the effects of orthodontic forces on the dental pulp, to firstly determine if any harmful effects were reported, and secondly, to deduce if these effects were permanent. The review was conducted independently by three assessors, and in accordance with the PRISMA guidelines [2]. The final material was categorized in accordance with a modified version of the Swedish Council of Technology Assessment in Healthcare guidelines [3]. A detailed search strategy was documented, with clearly defined inclusion and exclusion criteria. The authors do not provide insight into the potential limitations of the included studies. Ten included studies reported a significant reduction in the pulpal blood flow as a result of orthodontic treatment within the initial treatment period, followed by a recovery towards baseline Department of Restorative Dentistry, Glasgow Dental Hospital and School, 378 Sauchiehall Street, Glasgow, UK. ✉email: 1 Received: 7 January 2023 Accepted: 12 January 2023 Published online: 8 March 2023 40 values. The study was unable to clearly evidence the role of different forces on pulpal blood flow; however, reduction in blood flow between the main types of tooth movement were similar. All included studies measured pulpal blood flow using Laser Doppler Flowmetry (LDF). LDF is reported to be advantageous over pulp sensibility tests due to its objectivity and ability to test blood supply rather than sensation [4]. Assessments of changes in tooth sensibility were reported in three included studies, of which none reported permanent pulpal damage. Histological changes in the pulp were reported in two studies, which both reported fibrotic tissue formation; however, follow-up periods were limited to three weeks in both studies. The authors of the systematic review acknowledged limitations of the included studies, an important one being that most studies' scheduled follow-ups were limited to one month. This lack of long-term analyses prevents the authors' ability to fully answer the focus question, as there is no assessment of the long-term effect of orthodontic forces on the dental pulp. This review provides a good overview of the recent literature pertaining to the effect of orthodontic forces on the dental pulp with a robust search strategy implemented by the researchers. However, the assessment of study quality was poorly described and somewhat overlooked. Whilst the authors categorized included studies against recognized guidelines to mitigate against low-quality evidence, it is unclear how the quality of the original studies was determined and if a risk of bias assessment was carried out by the authors. This affects the value and credibility of the systematic review, and therefore its clinical applicability. Overall, this systematic review offers insight into the most current available evidence surrounding the adverse effects of orthodontic forces on the dental pulp, whilst comparing and collating its findings with the findings of previous studies. The authors recognised the limitations of the current available evidence and the need for further research. REFERENCES 1. Okuda BC, Tabbaa S, Edmonds M, Toubouti Y, Saltaji H. Direct to consumer orthodontics: Exploring patient demographic trends and preferences. Am J Orthod Dentofacial Orthop. 2021;159:210–6. 2. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. Syst Rev. 2021;10:1. 3. Bondemark L, Holm AK, Hansen K, Axelsson S, Mohlin B, Brattstrom V, et al. Longterm stability of orthodontic treatment and patient satisfaction: a systematic review. Angle Orthod. 2007;77:181–91. 4. Jafarzadeh H. Laser Doppler flowmetry in endodontics: a review. Int Endod J. 2009;42:476–90. COMPETING INTERESTS The author declares no competing interests. ADDITIONAL INFORMATION Correspondence and requests for materials should be addressed to Hel (...truncated)