Impact of clear aligners on gingivitis incidence and prevention strategies in adolescents and adults: a prospective observational study

Abstract

Objective

This study aims to analyze the differences in gingivitis incidence among adolescents and adults using clear aligners for orthodontic correction and to evaluate the effectiveness of prevention strategies on orthodontic outcomes.

Methods

This observational study included 120 patients undergoing clear aligner orthodontic treatment from June 2018 to September 2023. Participants were divided into an adolescent group (66 cases) and an adult group (54 cases), each further split into a study group and a control group. The control group patients maintained their daily lifestyle throughout the study period. The study group received personalized oral hygiene education and guidance on self-oral care techniques at each follow-up visit. Routine periodontal treatment and personalized oral hygiene education were provided, and the incidence of gingivitis was evaluated six months post-treatment. Statistical methods, including chi-square tests for categorical data, t-tests for continuous variables, and two-way ANOVA for group comparisons, were employed to ensure the robustness of the results.

Results

The incidence of gingivitis was significantly higher in the adolescent group compared to the adult group (P < 0.05). Specifically, within the adolescent group, the study group exhibited a higher gingival index (GI) than the control group (P < 0.05), while the difference in the adult group was not significant.

Conclusion

During clear aligner orthodontic treatment, adolescents are more prone to developing gingivitis than adults. Additionally, basic periodontal therapy, as opposed to verbal oral health education alone, can moderately reduce the incidence of gingivitis in clear aligner patients during treatment.

Introduction

Orthodontic treatment in dentistry is an important field of modern dental medicine and a key factor affecting individual social and psychological health and overall quality of life [1–3]. It can improve bite relationships and oral function by adjusting the position of the teeth and jaws, significantly enhancing facial aesthetics for patients [4]. Traditional metal braces, which use ligature wires to secure the archwire, are the most common conventional braces. However, they have drawbacks, such as being aesthetically unpleasing, inconvenient during eating and brushing, and irritating the inner side of the mouth, which can lead to oral inflammation [5, 6].

With the advancement of medical technology, Clear Aligner Therapy, an innovative orthodontic method, has become a preferred choice for adolescent and adult patients due to its excellent concealment and comfort. This technology uses transparent aligners designed and manufactured with computer assistance to precisely control tooth movement without being noticeable, optimizing treatment outcomes [7, 8]. Orthodontic treatment is no longer limited to simply “aligning teeth.” It now requires consideration of functionality, aesthetics, and its impact on oral and overall health.

The treatment process is convenient and comfortable for patients, and it aims to be a more aesthetically pleasing alternative to traditional metal braces [9, 10]. Invisible aligner therapy is now widely accepted to solve various dental issues, including crowding, spacing, overbite, underbite, and open bite. By closing gaps and correcting tooth alignment, clear aligners improve aesthetics and may alleviate mild sleep apnea symptoms through changes in jaw alignment [11].

The success of clear aligner therapy depends on factors such as the complexity of tooth movement, patient compliance, and the orthodontists’ experience. Studies indicate that the success rate for mild to moderate tooth movement ranges from 80 to 90%, demonstrating the efficacy of this technology [12–14]. Moreover, the development of clear aligner technology has driven advancements in orthodontic research and clinical practice.

Traditional fixed orthodontic appliances, as a classic method for orthodontic treatment, are commonly used to correct malocclusions. However, using metal components and adhesives significantly increases the risk of plaque accumulation and is a common cause of gingivitis [15, 16]. Among adolescents undergoing fixed appliance therapy, the prevalence of gingivitis ranges from 35 to 50%, which is notably higher than the 20–25% observed in adults [17, 18]. This difference is likely associated with hormonal fluctuations, poorer oral hygiene habits, and weaker adolescent plaque control abilities. In contrast, adults undergoing fixed appliance therapy have a lower incidence of gingivitis, likely due to more established oral care habits and reduced susceptibility to inflammation [19]. Additionally, the excessive adhesive used with fixed appliances can lead to open gingival embrasures (OGE), particularly prominent among adult patients [20]. Although fixed appliances achieve satisfactory outcomes in correcting malocclusions, their aesthetic limitations and impact on periodontal health remain challenges.

Clear aligners, as an innovative orthodontic treatment modality, have gained popularity among adolescent and adult patients due to their removability, high level of concealment, and precise control over tooth movement. However, this treatment requires significant patient compliance, with daily wear exceeding 22 h; failure to meet these requirements may extend treatment duration and reduce efficacy [6]. Studies show that compared with fixed appliances, adolescent patients treated with clear aligners generally exhibit lower plaque and gingivitis scores. Nevertheless, some studies suggest that the risk of gingivitis with clear aligners may, in some instances, approach that of fixed appliances, potentially due to cleaning difficulties caused by attachments and changes in the oral microenvironment [21–24].

Factors contributing to periodontal issues in adolescent patients during clear aligner treatment include fewer daily brushing sessions, pre-treatment white spot lesions, frequent consumption of carbonated drinks, reduced cleaning frequency after aligner placement, and a higher number of attachments [25, 26]. Additionally, levels of inflammation-related cytokines (such as CXCLs and ILs) are significantly elevated in adolescent patients following clear aligner therapy, suggesting that changes in the gingival microenvironment may further increase the risk of gingivitis.

Although existing studies have explored the effects of clear aligners and fixed appliances on gingival health, systematic research directly comparing the incidence of gingivitis between adolescents and adults under these two treatments still needs to be improved. Furthermore, discrepancies among current findings necessitate further investigation to clarify the specific impact of clear aligners on gingival health across different age groups. This study aims to address this gap by systematically analyzing the effects of these two types of orthodontic appliances on gingival health in patients of different age groups, providing scientific evidence for managing periodontal health during orthodontic treatment.

In this study, we conducted an in-depth exploration of gingivitis associated with clear aligner therapy. A total of 120 patients were divided into adolescent and adult groups for comparative analysis. Routine periodontal treatment and oral hygiene instructions were provided, and the incidence of gingivitis was evaluated after six months. Gingival index (GI) scores were assessed using standardized periodontal probes and specific guidelines such as the AAP Periodontal Disease Classification System. To ensure the rigor and reliability of statistical analyses, we performed normality tests. This study systematically investigated changes in gingivitis incidence before and after treatment and its impact on periodontal health, providing scientific guidance and optimized treatment strategies for clinical practice.

The primary goal of this study is to comprehensively evaluate the effectiveness of clear aligner therapy in different populations, particularly in the prevention and management of gingivitis. By analyzing the mechanisms and influencing factors of gingivitis and assessing the effectiveness of various preventive measures, this study aims to deliver refined health management strategies for orthodontic treatment, ensuring that patients achieve both aesthetic and safe, effective treatment outcomes.

Materials and methods

Study design

This prospective observational study investigates the impact of clear aligner orthodontic treatment on gingival health in adolescent and adult patients. The study adheres to ethical standards, including the Declaration of Helsinki, and the relevant ethics committee has approved the research protocol. The privacy and confidentiality of all participants were respected, with all data processed anonymously. Sample collection procedures were designed to minimize inconvenience and risk to participants. We ensured that all experimental procedures complied with national and international guidelines on biosafety and bioethics.

Criteria for participant selection

This observational study covers 120 patients who received clear aligner treatment in the Department of Stomatology between June 2018 and September 2023. The clear aligners used in this study were from the Invisalign brand, primarily made from SmartTrack material. These patients were divided into two groups: an adolescent group of 66 cases, with an average age of approximately 14.2 years, and an adult group of 54 cases, with an average age of approximately 25.7 years.

Power analysis was conducted to determine the sample size, ensuring scientific rigor and statistical reliability in the study design. Referring to existing studies on the incidence of gingivitis during clear aligner and fixed appliance treatments [17, 27], a medium effect size (Cohen’s d = 0.5) was assumed. Using the G*Power software, the minimum required sample size was calculated to be 88 participants at a significance level of α = 0.05 and a power (1-β) of 0.8. Considering potential dropout rates, the final sample size was increased to 120 participants, ensuring sufficient statistical power to detect differences between groups.

Each group was further divided into a study group and a control group, with 33 cases in each subgroup for the adolescent group and 27 cases in each for the adult group. The inclusion criteria for the study were as follows: (1) Patients had no systemic diseases or history of metal allergies. (2) Patients had not been exposed to nickel-contaminated environments. Since nickel exposure can independently affect periodontal health, patients with such exposure were excluded to avoid confounding effects. (3) There were no other metal restorations in the oral cavity. (4) Patients did not have a history of alcohol consumption or smoking. (5) Body mass index (BMI) was within normal range. (6) Apart from the third molars, there were no impacted or congenitally missing teeth. (7) Considering the severity of malocclusion, only patients with mild cases were selected for this study. (8) All patients could understand the study’s purpose and actively cooperate with the research process. (9) Consent was obtained from both the patients and their guardians. Participants exposed to a nickel-contaminated environment were excluded to avoid confounding effects, as nickel exposure can independently affect periodontal health, regardless of orthodontic treatment. The screening, grouping, and follow-up process of participants is shown in Fig. 1, illustrating the entire procedure from screening to analysis.

Fig. 1.

Participant screening, randomization, and follow-up process

Note: This study included a total of 120 participants, divided by age into an adolescent group (n = 66) and an adult group (n = 54). Each group was further randomized into a study group and a control group. Inclusion criteria included no systemic diseases or history of metal allergies, no exposure to nickel contamination, normal BMI, and no heavy drinking or smoking, among others (see Methods for details)

Group allocation and randomization

After enrollment, all study participants were allocated to either the study group or the control group using a computer-generated random number table to ensure a balanced distribution. Randomization maintained equilibrium between the adolescent group (33 participants per group) and the adult group (27 participants per group) and ensured an approximately 1:1 male-to-female ratio within each group. Participants were blinded to their group assignments, and all evaluations and treatments were conducted by uniformly trained healthcare professionals following standardized protocols.

Participants in the control group maintained their routine oral hygiene practices during the study. A periodontist assessed periodontal health at each follow-up visit and provided professional periodontal treatments, including supragingival and subgingival scaling and root planing, effectively removing factors promoting periodontal disease. Before cleaning, alkaline fuchsin dye was applied to all teeth surfaces, including buccal, lingual, and interproximal areas, to visualize plaque accumulation. Based on this feedback, participants were guided to improve their daily cleaning methods. This intervention primarily relied on professional treatment and visual feedback from plaque staining to optimize periodontal health without incorporating systematic behavioral intervention.

Participants in the study group received personalized oral hygiene education and technical guidance during follow-up visits. It included instructions on proper Bass brushing techniques, the use of dental floss and interdental brushes, and the operation of oral irrigation devices. Oral hygiene knowledge was reinforced at each follow-up through specially designed educational materials and regularly monitoring intervention effectiveness. These measures helped participants gradually establish and consolidate effective cleaning habits. Healthcare professionals recorded participants’ self-reported cleaning behaviors and clinical observations to monitor compliance, adjusting educational content as needed. Additionally, the study group received specific recommendations on details such as toothbrush replacement and interdental cleaning frequency to further enhance their oral hygiene levels.

The randomized allocation and differentiated intervention approaches ensured baseline consistency between groups while highlighting the specific impact of personalized education on periodontal health. All intervention and follow-up procedures adhered strictly to standardized protocols, ensuring the reliability and scientific validity of the study results.

GI assessment

The Gingival Index (GI) score was assessed using standardized periodontal probes and specific guidelines, such as the AAP Periodontal Disease Classification System (PMID: 14121956; PMID: 26125117). The GI categorizes the severity of gingivitis into four levels, 0–3, where 0 represents gingival health, 1 represents mild inflammation, 2 represents moderate inflammation, and 3 represents severe inflammation. The scoring criteria for GI were defined as follows: 0 indicated healthy gums; 1 indicated mild inflammation with slight color change and swelling, no bleeding upon probing; 2 indicated moderate inflammation with redness and significant swelling, bleeding upon probing; 3 indicated severe inflammation with marked redness, swelling, or ulceration, and spontaneous bleeding. After six months of orthodontic treatment, another oral examination was conducted, and the GI value was measured again to evaluate changes in gingival health during the treatment period.

In this study, all participants underwent a comprehensive periodontal health assessment before orthodontic treatment, including supra- and subgingival scaling and root planing, to ensure that the GI for each patient was 0 before wearing the orthodontic appliance. The assessment and treatment were administered by periodontal specialists who received specific training using standardized periodontal tools (ultrasonic and hand scalers). Tooth selection for pre-treatment assessment followed the Ramfjord teeth index (teeth 16, 21, 24, 36, 41, 44), which served as representative teeth for regular periodontal health tracking. The follow-up interval for both groups of patients was every 1.5 months. During each follow-up visit, all patients had their GI evaluated by the same experienced periodontist according to the guidelines in the 2nd edition of Clinical Periodontology.

Baseline measurement: Initial assessment was conducted before orthodontic treatment to ensure all participants had a GI score of 0. Follow-up assessments: Evaluation performed at each follow-up visit after the start of treatment (every 1.5 months) until the end of the study. Post-treatment assessment: Final GI assessment conducted immediately after the completion of orthodontic treatment and compared with baseline and interim assessment results.

Data recording and storage: A data manager recorded all data electronically and kept it in a secure database for future statistical analysis and validation. After six months of orthodontic treatment, another oral examination was conducted, and the GI value was measured again to evaluate changes in gingival health during the treatment period.

Statistical analysis

To enhance the rigor and reliability of the statistical analysis, we first conducted tests for normality, such as the Shapiro-Wilk test, on the data. It ensured that the data from each group—pre-treatment, 1.5-month, and post-treatment groups—met the normal distribution requirements before performing t-tests. Additionally, a test for homogeneity of variances (Levene’s test) was performed to decide whether to use the equal or unequal variance version of the t-test. To examine the changes in GI scores between the two groups and within each group during the treatment period, a two-way ANOVA was used for analysis. Multiple comparison correction methods, such as Bonferroni correction, were employed to reduce Type I errors for comparisons between multiple groups. All statistical analyses were carried out using the latest version of the SPSS software to ensure the accuracy and efficiency of the analysis. A significance level of P < 0.05 was considered statistically significant.

Results

Comparison of the incidence rate of Gingivitis in different age groups

Based on the data collected in this study (Table 1), we compared the incidence of gingivitis in the adolescent and adult groups after using clear aligners for correction. The statistical results in the table show that the male-to-female ratio in both the experimental and control groups was maintained at 1:1, which helps eliminate errors caused by gender differences (Table 1). The results showed that in the adolescent group (mean age 14.2), out of 66 cases, 26 cases developed gingivitis (Fig. 2a), accounting for 39.39%. In contrast, in the adult group (mean age 25.7), out of 54 cases, 38 cases had gingivitis (Fig. 2b), reaching a rate of 70.04%. Among the 120 patients, 54 cases experienced gingivitis, resulting in an overall incidence rate of 50.00% (Fig. 2c).

Table 1.

Comparison of Gingivitis incidence between adolescents and adults

Group	Number of Gingivitis Cases (Male/Female)	Number of Normal Cases (Male/Female)	Total	Average age	Percentage (%)
Adolescent Group	26 (13/13)	40 (20/20)	66	14.2	39.39
Adult Group	38 (19/19)	16 (8/8)	54	25.7	70.04
Total	54	56	120		50.00
x2					11.45
P-value					< 0.05

Fig. 2.

Comparison of gingivitis incidence between adolescents and adults

The chi-square test results used in the statistical analysis showed a P-value less than 0.05, indicating a significant difference in the incidence of gingivitis between the adolescent and adult groups. Specifically, the overall gingivitis rate among all patients wearing aligners was evaluated before the subgroup analysis and statistical comparisons were conducted. Overall, the incidence of gingivitis was significantly higher in the adult group compared to the adolescent group.

In conclusion, during clear aligners correction, the incidence of gingivitis in adult patients is significantly higher than in adolescent patients. This finding highlights the importance for adults undergoing clear aligners correction to pay closer attention to periodontal health management and the implementation of preventive measures.

Analysis of GI changes during Clear aligners correction

In this study, we conducted a detailed comparison of changes in GI before and after clear aligner treatment between the study and control groups in the adolescent and adult cohorts (Table 2). The results indicated statistically significant differences in GI changes across different groups and time points.

Table 2.

Comparison of gingival index (GI) between study and control groups in adolescents and adults

Group		Number of Cases	GI			t-value	P-value
			Before Treatment	Treatment 1.5 Month	During Treatment
Adolescent Group	Control Group	33	0.15 ± 0.07	0.50 ± 0.12	0.59 ± 0.19a	4.421	0.035
	Study Group	33	0.17 ± 0.05d	1.15 ± 0.18	1.49 ± 0.25abc	27.424	0.000
t-value			-0.255	-2.868	-2.772
P-value			0.799	0.006	0.007
Adult Group	Control Group	27	1.19 ± 0.17	1.31 ± 0.19	1.42 ± 0.21b	3.384	0.067
	Study Group	27	1.18 ± 0.14d	1.32 ± 0.15	1.42 ± 0.20ad	3.803	0.041
t-value			0.028	-0.053	-0.003
P-value			0.977	0.958	0.998

Note: ^a Before Treatment vs. During Treatment p < 0.05 indicates a significant difference. ^b Before Treatment vs. During Treatment p > 0.05 indicates no significant difference. ^c Control Group vs. Study Group p < 0.05 indicates a significant difference. ^d Control Group vs. Study Group p > 0.05 indicates no significant difference

In the adolescent group, the GI in the study group significantly increased from 0.17 before treatment to 1.49 during treatment (standard deviation increased from 0.05 to 0.25, t = -27.424, P-value (0.000), less than 0.05), showing a more pronounced change. In the control group, the GI increased from 0.15 before treatment to 0.59 during treatment (standard deviation increased from 0.07 to 0.19, t = 4.421, P-value (0.035), which is less than 0.05), indicating that the treatment process significantly increased the risk of gingivitis. A comparison of GI during treatment between the two groups revealed that the GI increase in the study group was significantly higher than in the control group (P-value (0.007), less than 0.05). Furthermore, significant changes in GI were observed between the study and control groups starting from 1.5 months into treatment (P-value (0.006), less than 0.05), suggesting that adolescent patients face a higher risk of gingivitis early in the treatment process (Table 2). The larger increase in the study group may reflect lower adherence to oral hygiene education among adolescent patients, while the minor increase in the control group highlights the more direct effect of basic periodontal treatment in reducing the risk of gingivitis.

In the adult group, the GI in the control group increased from 1.19 before treatment to 1.42 during treatment, but this change was not statistically significant (P-value (0.067), greater than 0.05). In the study group, the GI increased from 1.18 before treatment to 1.42 during treatment, with a statistically significant change (P-value (0.041), less than 0.05). However, intergroup comparisons showed no significant differences (P-value (0.067), greater than 0.05). Similarly, the GI measurements at 1.5 months in the adult group showed no significant changes (P-value (0.958), greater than 0.05) (Table 2), indicating that personalized oral hygiene education and basic periodontal treatment had similar effects in adults, likely due to their higher adherence and established oral hygiene habits.

These findings suggest that the use of clear aligners in adolescents resulted in a more significant increase in the risk of gingivitis, while in adults, there was no significant difference in the effects of personalized hygiene education and basic periodontal treatment. It highlights the need to strengthen personalized education and regular periodontal treatment during orthodontic treatment in adolescents (Fig. 3).

Fig. 3.

GI before and during treatment by group

Discussion

Clear aligners have been widely used in orthodontic treatment in recent years, and compared to traditional metal braces, they offer advantages such as aesthetics and comfort, making them particularly popular among patients, especially young patients [28]. However, clear aligner usage can lead to oral health issues such as gingivitis during treatment [21, 22, 29], raising concerns among clinicians and researchers. Gingivitis, as a common oral disease, if not promptly treated, can progress to more severe periodontal diseases, impacting the patient’s oral health [21, 22]. Therefore, studying the relationship between clear aligners and the incidence of gingivitis and exploring effective preventive measures holds significant clinical and scientific importance.

Some studies have found a higher incidence of gingivitis among users of clear aligners, suggesting that clear aligners may increase plaque accumulation, leading to gingivitis [21]. However, some studies have not found a significant difference in the incidence of gingivitis with clear aligners [22, 30, 31]. In this study, through a comparison of two groups of adolescents and adults, it was found that the incidence of gingivitis was significantly higher in the adolescent group compared to the adult group (Fig. 3). This finding addresses the limitations of existing studies focusing on a single population [20, 25]. Through this research, a more comprehensive understanding of the impact of clear aligners on gingival health can be achieved.

This study has several strengths in its design. Firstly, the relatively large sample size allows for a more accurate reflection of real-world conditions and indicates that the statistical power of the results is reliable. Secondly, the study employed a strict grouping method, subdivided into study and control groups within each group. The study also included routine periodontal treatment intervening measures and oral hygiene guidance. By evaluating the GI and the incidence of gingivitis, the study could provide a comprehensive reflection of the impact of clear aligners on gingival health. Overall, the higher gingivitis rates observed in all adult groups highlight the importance of periodontal health management and preventive measures in adults.

Comparative study results show that the incidence of gingivitis in the adolescent group was significantly higher than that in the adolescent control group, as well as higher than the differences observed between the adult study and control groups. This significant difference may be related to the physiological characteristics, oral hygiene habits, and poorer compliance of adolescents. Specifically, hormonal fluctuations during puberty increase gingival vascular permeability, making adolescents more sensitive to local inflammatory factors [32]. Moreover, adolescents often exhibit less consistent oral hygiene practices than adults, with improper brushing techniques and inadequate cleaning leading to plaque accumulation and a higher risk of gingivitis. These physiological and behavioral factors together contribute to the higher risk of gingivitis in the adolescent group.

In addition, adolescents often find it challenging to follow proper oral hygiene education. Studies have shown that the proportion of adolescents who brush their teeth effectively each day is much lower than that of adults, and their use of additional cleaning tools (such as dental floss or interdental brushes) is also less frequent [33, 34]. It highlights the urgent need for more effective preventive measures for adolescents during orthodontic treatment, especially in improving oral hygiene compliance.

In contrast, adults typically demonstrate higher compliance, including attending follow-up appointments, regular cleanings, and using oral hygiene aids, which may explain the smaller changes in gingivitis incidence during orthodontic treatment [35]. To reduce the risk of gingivitis in adolescents undergoing clear aligner therapy, we recommend paying particular attention to oral hygiene during treatment. Specific measures include proper brushing techniques, regular plaque removal, routine professional cleanings, and oral examinations to eliminate local pathogenic factors promptly. Additionally, fostering good hygiene habits, such as brushing twice daily and rinsing before meals, is crucial. It is also important to focus on physical and mental health, maintaining a regular lifestyle to ensure a positive interaction between oral and overall health.

Furthermore, this study also found that the use of clear aligners showed significant changes in the gingival health index, especially in the study group of adolescents, where the increase in the GI was more pronounced. It may indicate that while clear aligners offer convenience and aesthetics for teeth correction, their impact on the periodontal environment should not be overlooked. Additionally, the adolescent group exhibited a significantly greater increase in GI than the adult group, indicating poorer oral hygiene habits and lower compliance among adolescents. Even with oral health education interventions, the improvement remained limited. Therefore, we recommend reinforcing regular periodontal health check-ups for adolescent patients during orthodontic treatment and enhancing their periodontal health through personalized oral hygiene education programs. Moreover, the design and use of clear aligners should consider the biomechanical properties of the teeth, ensuring that each tooth’s movement stays within a safe biomechanical pressure range. Future research should further explore the specific impact of clear aligners with different designs on gingival health and how to improve designs to reduce their adverse effects on the gums.

In the comparison of interventions, basic periodontal treatment demonstrated significant short-term effects. In the adolescent control group, patients who received basic periodontal treatment had significantly lower GI values than those in the study group who underwent oral health education. It indicates that professional supragingival and subgingival scaling effectively remove dental plaque and reduce the occurrence of gingivitis. However, although health education showed less immediate impact than basic treatment, it could gradually improve patient compliance and gingival health, especially in long-term follow-ups. Adolescent patients’ lower compliance may limit the short-term effectiveness of health education. Therefore, future interventions should integrate health education with basic periodontal treatment to enhance long-term efficacy.

Overall, this study followed the incidence of new gingivitis cases and the GI indices during clear aligner treatment in both adolescent and adult groups, revealing the mechanisms of gingivitis development in this treatment approach (Fig. 4). Clear aligner therapy led to increased difficulty in maintaining oral hygiene, plaque accumulation, and poorer adaptation to the aligners. Therefore, we recommend implementing personalized oral hygiene education tailored to the specific needs of individual patients, combined with regular professional periodontal treatment, to effectively prevent and control gingivitis. Additionally, optimizing the design of clear aligners to minimize mechanical irritation and the risk of plaque accumulation could further enhance their clinical safety and effectiveness. Our research also provides valuable guidance for clinical practice. Firstly, they highlight the need for clinicians to pay attention to the gingival health issues of adolescents when providing clear aligners for orthodontic treatment. Secondly, there is an emphasis on strengthening personalized oral hygiene education to prevent and reduce the occurrence of gingivitis, ultimately improving patient treatment compliance and outcomes. By implementing personalized oral hygiene guidance, the incidence of gingivitis can be significantly reduced, enhancing the effectiveness of clear aligners’ orthodontic treatment. At the same time, we call for future studies on more extensive and more diverse populations to validate and expand upon these findings. It will provide a more substantial scientific basis for ensuring the safety and effectiveness of clear aligner therapy.

Fig. 4.

Mechanism of gingivitis occurrence during clear aligner orthodontic

However, this study has several limitations. First, although the sample size is relatively large, it is still limited, which may restrict the generalizability of the findings. Additionally, this study did not consider the potential impact of gender differences on the results. Future research should expand the scope of analysis to address this aspect. Second, the study duration was relatively short, only six months, which may not be sufficient to capture long-term changes in gingival health fully. Previous studies have shown that gingival health is influenced by various long-term factors, such as lifestyle, dietary habits, and overall health, and short-term observations may fail to reveal the cumulative effects of these factors. Therefore, future studies should incorporate longer follow-up periods to comprehensively evaluate the long-term impact of interventions on gingival health and validate the stability of short-term findings.

Moreover, the participants in this study were primarily drawn from a single region, and differences in regional and cultural backgrounds may affect the generalizability of the results. Future research should consider larger-scale, multi-center, long-term follow-up studies to further validate and expand upon the findings of this study. Additionally, other relevant factors, such as dietary habits, genetic predispositions, and psychological factors, should also be explored better to understand their role in the incidence of gingivitis.

Author contributions

Haiying Zhang contributed to the study design, data collection, and analysis, and was responsible for drafting the manuscript. Shuangyan Bi participated in data acquisition and clinical assessments. Xiaojun Zhang contributed to the interpretation of the data and critically reviewed the manuscript for intellectual content. All authors read and approved the final manuscript.

Funding

This study was supported by Zhaoqing Science and Technology Innovation Guidance Category Project ((2020) No. 26 202004031206).

Data availability

The datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

The study adheres to ethical standards, including the Declaration of Helsinki and ethics approval for this study was obtained from the Clinical Ethics Committee of Zhaoqing Medical College. All participants gave informed consent to participate in the study. For participants under the age of 16, consent was obtained from their parents or legal guardians.

Consent for publication

Informed consent to publish was obtained from all individual participants included in the study. For participants under the age of 16, consent was obtained from their parents or legal guardians. This consent included permission to use any relevant images or data that could potentially identify the participants.

Competing interests

The authors declare that they have no conflicts of interest regarding the publication of this paper.