Dental and Periodontal Alterations Associated with the Use of the Interproximal Reduction Technique: A Systematic Review

Highlights

What are the main findings?

• The IPR technique does not produce negative effects on the patient when used correctly. Furthermore, it can be effective in counteracting the negative effects of orthodontic treatment and has not been associated with the incidence of caries, alterations in the composition of dental enamel, loss of clinical attachment, or bleeding. Nevertheless, patient selection must be done with great care.
• According to the literature, applying fluoride varnish and coolant spray, along with using ultra-thin finishing and polishing discs, improves the outcomes of the IPR technique. These methods are beneficial for preventing wear of the outer enamel, reducing abrasion, and avoiding an increase in pulp temperature.

What are the implications of the main findings?

• Adults are increasingly opting for orthodontic treatments that are more attractive and less intrusive than traditional braces, like invisible aligners, making the IPR technique highly relevant again. Even with scientific support, its application raises some doubts.
• Updated information is compiled in this study, clarifying doubts about the IPR technique’s application, efficacy, and adverse effects on teeth.

Abstract

Background/Objectives: Interproximal reduction (IPR), also known as dental stripping, is a commonly used orthodontic technique to gain space, avoid extractions, and correct tooth size discrepancies, particularly in contemporary orthodontics and clear aligner therapy. The aim of this systematic review was to update the evidence from the last 10 years regarding the dental and periodontal effects associated with IPR. Methods: A systematic review of the literature was conducted including studies published between January 2015 and July 2025. Searches were performed in PubMed, SciELO, LILACS, Cochrane Library, and Google Scholar. Primary studies reporting dental and/or periodontal outcomes related to IPR were included. Study selection and data extraction were performed following PRISMA guidelines. Results: Twelve studies met the inclusion criteria, comprising in vitro and in vivo designs. The available evidence indicates that IPR is associated with transient changes in enamel surface roughness and minimal increases in pulp temperature, which remains below critical thresholds when appropriate techniques and cooling measures are used. No consistent evidence of increased caries risk, periodontal deterioration, or tooth sensitivity was reported. Surface polishing and fluoride application were frequently associated with more favorable outcomes. Conclusions: Based on the available evidence from the last decade, IPR appears to be a clinically safe orthodontic procedure when performed with proper technique, adequate case selection, and appropriate finishing protocols. However, heterogeneity among study designs highlights the need for further well-designed clinical studies to strengthen the evidence base.

1. Introduction

Reduction (IPR), also known as dental stripping, is a frequently employed orthodontic method with three main purposes: to generate space for tooth alignment, to prevent the need for tooth extractions, and to correct Bolton type discrepancies. Even though it is scientifically proven, there are still questions about how it is used, how well it works, and how it might affect the tooth and the supporting tissues. Therefore, it is important to stay informed about the effects of this technique on the tooth and periodontium [1].

The irregularities resulting from the stripping process may increase susceptibility to plaque accumulation and caries formation. However, multiple studies have shown that stripping teeth does not increase the likelihood of cavities or periodontal issues [1,2].

Pulp effects are discussed in several studies, suggesting cooling techniques like air and water spraying during tooth reduction to prevent increased pulp temperature. However, it is also noted that the use of water hinders visibility [3,4]. Nevertheless, more recent studies support the use of water spray as a safety measure [5].

Concerning tooth size differences, in 1944, Ballard’s study suggested that the mesiodistal width of the lower anterior teeth should be reduced to solve the issue [6]. Later, Bolton reiterated the need for dental stripping to balance the lack of harmony in dental dimensions and malocclusion [7].

Although there was more skepticism in the early studies on this topic, the fact that it can avoid the need for extraction in various cases of dental crowding has remained valid [8,9]. Currently, there is an increase in adult patients seeking orthodontic treatment, expressing a desire for more aesthetic and comfortable alternatives to conventional fixed appliances, such as the use of clear aligners, in which the IPR technique is once again having a significant impact [10]. The objective of this systematic review was to update the results obtained in recent years regarding the effects of the IPR technique on the teeth and periodontium. The relevance of this review lies in the fact that, in addition to updating the results to date, the selected articles have been arranged chronologically; it is very interesting to observe the evolution of the studies, materials and methods and the results obtained over time regarding this topic.

2. Materials and Methods

A systematic review was conducted compiling information published in the last 10 years from various databases, including PubMed, SciELO (Scientific Electronic Library Online), LILACS (Latin American and Caribbean Literature on Health Sciences), Cochrane and Google Scholar. The following MeSH terms were used for the search: Dental stripping, Effects, Orthodontic, Dental effects, Interdental stripping, and Interproximal reduction.

The search strategy was adapted to the syntax and indexing terms of each database. The complete and reproducible search strings used for PubMed, SciELO, LILACS, Cochrane, and Google Scholar are reported in detail in the Supplementary Material (List S1).

Database-specific filters were applied when available, including publication date (January 2015–July 2025), language (English and Spanish), and availability of full text. Duplicate records were removed prior to screening. Before screening, duplicate entries were eliminated. Details on the number of records taken from each database are provided in the PRISMA 2020 flow diagram.

Inclusion criteria were scientific articles published between January 2015 and July 2025 that included cross-sectional studies, case–control studies, cohort studies, or case reports, published in English and Spanish, with full-text availability to allow complete methodological assessment, and presenting information on IPR and its effects on the tooth and periodontium.

Studies published as theses, conference proceedings, and posters were excluded. Systematic reviews and meta-analyses were excluded, as the objective of this review was to synthesize primary evidence reporting direct dental and periodontal outcomes associated with interproximal reduction. Studies without full-text availability were also excluded, as complete methodological and outcome assessment was not possible.

Study selection was initially performed by one reviewer. To minimize selection bias, a second author independently verified the eligibility of the included studies, and any disagreements were resolved by consensus.

This review was conducted and reported in accordance with the PRISMA 2020 statement, where applicable, and a completed PRISMA checklist is provided as Supplementary Material (Table S1).

3. Results

3.1. Study Selection

The PubMed search yielded a total of 21 articles, 11 of which met the selection criteria; SciELO yielded three results, two of which met the criteria; the LILACS database yielded nine results, two of which met the inclusion criteria; Cochrane yielded one result that did not meet the criteria and Google Scholar yielded two results that did not meet the inclusion criteria. The review used 12 articles that met the inclusion criteria (Figure 1).

Because study designs and reported outcomes varied, the results are presented as a qualitative synthesis, including some quantitative data when available.

3.2. Table Summarizing the Selected Studies

Table 1. Information on the articles that met the selection criteria.

Year	Author	Type of Study	Objective or Topic Covered	Materials and Methods	Results and Conclusion
2015	Hellak et al. [11]	In vitro	To investigate the rate of enamel demineralization after IPR.	Using five different systems, the loss of substance was analyzed by optical emission spectrometry.	No potential bacterial colonization was observed within the erosive environment left by the IPR on the tooth. It was concluded that whenever there is wear of the outer enamel layer, there will be an increase in demineralization and that polishing the surface after IPR does not appear to influence a reduction in the degree of demineralization.
2019	Kaaouara et al. [12]	In vivo	The wear of enamel was studied in vivo at the macroscopic and microscopic levels.	Interdental stripping was performed on patients undergoing orthodontic treatment and analyzed using a scanning electron microscope.	Regardless of the type of material used for grinding, the enamel surface exhibited a degree of roughness with grooves and ridges of varying depths and widths. It was found that using files and oscillating discs produced smoother, less rough surfaces than hand tools (abrasive strips and files), and that using finishing and polishing discs as a final step after grinding reduced the amount of abrasion.
2019	Mohimd et al. [13]	In vivo	To evaluate the evolution of worn proximal dental surfaces after exposure to the oral environment for 4 months, with and without fluoride protection.	To quantify the percentage of mineral elements, scanning electron microscopy was used for qualitative analysis, and Energy Dispersive Spectrometry (ESS) was used for quantitative analysis.	After 4 months in the oral environment, there was an improvement in the percentage of mineral elements in both groups, but the results were better for those who were treated with fluoride varnish.
2019	Sehgal et al. [5]	In vitro	Changes in pulp temperature were analyzed during different interproximal grinding procedures.	Interproximal grinding procedures (diamond burs, with and without cooling and diamond abrasive strips).	An increase in temperature was observed with all abrasion methods, but none of the techniques resulted in an increase above the critical level of 5.5 °C suggested by Zach and Cohen [14]. It was concluded that the pulp temperature increase can be limited by using a cooling spray and refreshing water during the procedure.
2021	Sorel et al. [15]	Analytical, critical and illustrative.	To illustrate an approach based on diagnosis, analysis of dental disharmony, assessment of the magnitude of stripping and its consequences and the prognosis.	A diagnostic approach is used, analyzing the dental disharmony, assessing the extent of the stripping and its consequences, and finally, providing a prognosis. Clinical illustrations of treated cases are provided.	This article emphasizes that the gingiva and gingival festoon are essential elements for good periodontal health and a harmonious smile and that stripping can be a good alternative to counteract the negative indirect effects of orthodontic treatment, which indirectly influence the gingival festoon and particularly the papillae. Clinical cases illustrate the improvement in the appearance of the dental papilla in the presence of black triangles, using the IPR technique.
2021	Cremonini et al. [16]	In vitro	A qualitative analysis of the enamel surface at the contact point is performed, before and after the IPR.	Comparing two types of abrasive strips, using different techniques, including scanning electron microscopy (SEM), and the use of a scanner and 3-Shape Ortho Analyzer Software (3Shape, Copenhagen, Denmark).	It was concluded that there will always be a change in the shape of the contact point, and that the surface morphology will depend on the extent of wear, and that the type of strip did not have a statistically significant impact on the variation in the morphology.
2022	Brutus et al. [17]	Microscopic study of atomic force.	The nanotopography of enamel was evaluated after different IPR techniques.	The nanotopography of the enamel is evaluated after different IPR techniques (discs, burs and manual strips).	It was concluded that no IPR method was significant in the nanotopography of tooth enamel, with or without polishing, and that the reduction in roughness with polishing was only significant in disc wear.
2023	Shalchi et al. [18]	Retrospective cohort study.	Effects of IPR on gingival health (clinical attachment loss and bleeding on probing), as well as the incidence of caries in orthodontic patients without interproximal wear and patients who received IPR, with or without fluoride application.	Effects of IPR on gingival health (clinical attachment loss and bleeding on probing), as well as the incidence of caries in orthodontic patients without interproximal wear and patients who received IPR, with or without fluoride application.	There were no significant differences in the incidence of caries, clinical attachment loss, and bleeding on probing between patients receiving the IPR and those not. The incidence of caries also showed no significant differences between teeth that received fluoride after the IPR and those that did not.
2023	Katsigialou et al. [19]	In vivo	The enamel roughness and elemental composition were evaluated after mechanical and manual IPR in patients undergoing orthodontic treatment.	Optical profilometry, Raman spectroscopy, scanning electron microscope analysis, and energy-dispersive X-ray spectroscopy (EDX) analysis were used.	Both methods increased enamel roughness with no significant differences between the techniques. IPR did not significantly alter the molecular structure according to Raman and EDX analyses and no alterations in the elemental composition of the enamel were found after at least 6 months of intraoral exposure.
2024	Serbanoiu et al. [20]	Comparative analysis.	A comparative analysis of enamel roughness was performed after IPR using diamond burs, abrasive strips and discs.	Comparative analysis of enamel roughness after IPR with diamond burs, abrasive strips and discs, using scanning electron microscopy (SEM) and atomic force microscopy (AFM).	The nanotopographic and roughness level result after IPR varies according to the instruments and thicknesses used, with the thinnest strips and discs (15 μm), preserving the quality of the enamel surface and even eliminating natural wear marks.
2024	Nucci et al. [21]	Critical, informative and up-to-date analysis.	It discusses periodontal health versus interproximal enamel reduction and points out the causes of the negative effects after IPR.	Through citations and literature reviews, the topic of the relationship between the IPR and periodontal health is updated.	The study found that IPR requires a thorough examination and patient selection process and notes that it could cause negative effects if performed in contraindicated cases, such as grooves on the interproximal surface of the tooth, hypersensitivity, damage to the dental pulp, and an increased risk of interproximal caries. It concludes that IPR is useful for reducing or eliminating black triangles.
2024	Dahhas et al. [22]	Critical, informative and up-to-date analysis.	A critical analysis of the indications, techniques, and results of the IPR is made in the context of aligners, and the research results are clearly and systematically presented.	Through citations and literature reviews, the research results, indications, IPR techniques, as well as their different effects on the tooth and periodontium, are updated and clarified in a clear and orderly manner.	There is an increase in pulp temperature, but it does not exceed the critical threshold of 5.5 °C. The treated surface tends to exhibit greater roughness. There are no significant changes in the enamel nanotopography between polished and unpolished surfaces, but the surface is slightly smoother after polishing, which is why post-polishing is recommended. Susceptibility to caries has been refuted, provided the patient maintains good oral hygiene and the IPR procedure is performed accurately. The absence of periodontal problems is also confirmed. IPR does not increase tooth sensitivity.

IPR: Interproximal reduction. ESS: Energy Dispersive Spectrometry. EDX: Energy-dispersive X-ray spectroscopy. SEM: Scanning electron microscopy. AFM: Atomic force microscopy.

provides a chronological, summarized, and specific overview of the evolution of studies on the topic of IPR. It shows a balance in research conducted during the last ten years.

Prior research indicates that IPR impacts the tooth and periodontium in different ways. Yet the impacts are favorable if the technique is sound, along with a clear protocol and respecting diagnostic methods, indications, and contraindications. Among the main findings observed in the studies, we found that after IPR, the surfaces exhibit greater roughness; however, a slightly smoother surface can be achieved after the use of thermoplastic elastomer (TPE) finishing and polishing discs, making post-abrasion polishing advisable.

After exposure to the oral environment for up to 4 months, studies reported an increase in the mineral content of interproximal enamel surfaces, with more favorable mineral recovery observed in teeth treated with fluoride varnish compared to untreated surfaces.

All evaluated IPR techniques resulted in an increase in pulp temperature; however, reported values remained below the critical threshold of 5.5 °C described in the literature, particularly when water cooling was used.

Enamel surface roughness increased after IPR across different techniques; however, studies using finishing and polishing protocols, particularly discs with thicknesses of approximately 15 μm, reported smoother surfaces and partial elimination of natural wear marks.

The IPR technique is not associated with an increase in caries, periodontal problems, or tooth sensitivity; however, it is important to carefully select the material and thickness to be used, as well as consider the patient’s needs, to ensure satisfactory results.

4. Discussion

This review about IPR details the methodology and study results. The analyzed studies conclude that, when using an appropriate technique and respecting the indications for IPR, the effects are not negative for the patient, as indicated by the studies carried out by Sorel, Nucci, and Dahhas [15,21,22]. Hellak, in his in vitro study, concluded that whenever there is wear of the outer enamel layer, there will be an increase in demineralization and that polishing the surface after IPR does not appear to influence the reduction in the degree of demineralization [11]. Similar to the findings of Mohimd, who evaluated the evolution of worn proximal tooth surfaces after exposure to the oral environment for 4 months, found an improvement in the percentage of mineral elements in both groups, but the results were better in those treated with fluoride varnish [13].

Kaaouara performed interdental stripping on patients undergoing orthodontic treatment and concluded that the use of oscillating files and discs produced smoother, less rough surfaces than manual instruments and that the use of finishing and polishing discs as a final step after removal reduces the amount of abrasion [12]. Sehgal discusses changes in pulp temperature during different interproximal removal procedures, concluding that the increase in pulp temperature can be limited by using a cooling spray during the procedure [5]. Sorel mentions that stripping can be a good alternative to counteract the negative indirect effects of orthodontic treatment that indirectly influence the gingival festoon and particularly the papillae and illustrated the improvement in the appearance of the dental papilla with clinical cases [15].

According to Cremonini, the shape of the contact point will always change, and surface morphology will depend on wear [16]. According to Brutus, IPR methods did not significantly change tooth enamel nanotopography, with or without polishing, and polishing only mattered with disc wear [17]. Shalchi indicated that there are no significant differences in the incidence of caries, clinical attachment loss, and bleeding on probing between patients receiving IPR and those not [18], coinciding with the study by Dahhas, which refutes the risk of developing caries [22]. Katsigialou, in an in vivo study, concluded that no alterations in the elemental composition of enamel were found after at least 6 months of intraoral exposure [19]. Serbanoiu performed a comparative analysis of enamel roughness after interproximal enamel reduction (IPR) using diamond burs, abrasive strips, and discs, employing scanning electron microscopy (SEM) and atomic force microscopy (AFM). His analysis revealed that the nanotopographic and roughness levels after IPR vary depending on the instruments and thicknesses used. The thinnest strips and discs (15 μm) preserved the enamel surface quality and even eliminated natural wear marks [20]. Nucci discusses periodontal health in relation to interproximal enamel reduction and agrees that IPR requires careful patient examination and selection. He points out that it could cause negative effects if performed in contraindicated cases, such as grooves on the interproximal surface of the tooth, hypersensitivity, damage to the dental pulp, and an increased risk of interproximal caries [21].

Previous systematic reviews on interproximal reduction have reported similar conclusions regarding the absence of clinically significant adverse effects when appropriate protocols are followed. The present review expands on this evidence by providing an updated chronological synthesis of primary studies published over the last decade, including recent investigations related to contemporary orthodontic techniques and clear aligner therapy.

This systematic review has some limitations. The considerable heterogeneity in study design (e.g., in vitro, observational, narrative analyses), methodologies, and outcome measures among the included studies prevented strong causal inferences and quantitative synthesis. Therefore, conclusions should be interpreted with caution. Furthermore, this heterogeneity did not allow for a formal assessment of the risk of bias because it prevented the application of a single validated appraisal tool. Second, only studies published in English and Spanish with full-text availability were included, which may have led to the exclusion of potentially relevant evidence. Beyond that, the restricted number of clinical trials and the in vitro aspect of some articles might constrain the generalizability of the conclusions.

Another limitation of this review is the exclusion of studies without full-text availability, which may have resulted in the omission of potentially relevant data. However, this criterion was applied to ensure transparency, reproducibility, and accurate extraction of methodological details and outcomes. Although systematic reviews on interproximal reduction exist, they were not included in the formal synthesis because they do not contribute to primary outcome data. However, their conclusions are consistent with the findings of the primary studies included in this review.

Despite these limitations, this review provides an updated and structured synthesis of the dental and periodontal effects associated with interproximal reduction. This study’s strength lies in its synthesis of dental and periodontal changes from articles, considering methodology and results, in relation to removable partial dentures (RPDs). This information is intended to be readily available to dentists for use with their patients.

5. Conclusions

Based on the last 10 years of results, IPR has different effects on the tooth and periodontium during and after orthodontic treatment. Available evidence suggests that IPR is not associated with clinically relevant adverse effects when performed following appropriate protocols. However, these conclusions are mainly based on in vitro and non-randomized studies; therefore, future well-designed prospective clinical trials are needed.