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Incidence and risk factors of alveolar bone dehiscences and fenestrations after clear aligner therapy with Class II elastics: a retrospective study

BMC Oral Health volume 25, Article number: 644 (2025) Cite this article

Abstract

Background

In clear aligner therapy (CAT), Class II elastics are widely used to reinforce the anchorage during the distalization of upper molars, however, their association with alveolar bone dehiscences (ABDs) and fenestrations (ABFs) in the anterior region remains unclear. The aim of this research is to assess the incidence of ABDs/ABFs in adult patients undergoing non-extraction CAT with Class II elastics, and to explore risk factors associated with the occurrence of ABDs/ABFs.

Methods

Thirty adult patients with Class II malocclusion who underwent non-extraction CAT with Class II intermaxillary elastics were enrolled in this study. Cone-beam computed tomography (CBCT) images were obtained before (T0) and immediately after (T1) CAT to assess the occurrence of ABDs/ABFs on the labial and lingual sides of anterior teeth. Chi-square tests were used to compare the incidence of ABDs/ABFs at T0 and T1, meanwhile, binary logistic regression was utilized to analyze the risk factors associated with ABDs/ABFs at T1.

Results

On the labial side, the incidence of ABDs increased significantly in the mandibular central incisors (from 36.7 to 62.8%, P < 0.05), mandibular lateral incisors (from 36.7 to 70.0%, P < 0.05), mandibular canines (from 31.7 to 53.3%, P < 0.05) and maxillary canines (from 30.0 to 55.0%, P < 0.05). While on the lingual side, it increased significantly in the maxillary central incisors (from 1.7 to 23.3%, P < 0.05), lateral incisors (from 6.7 to 38.3%, P < 0.05), and canines (from 21.7 to 46.7%, P < 0.05). The incidence of ABFs only increased on the labial side of the maxillary canines and mandibular central incisors. The occurrence of maxillary ABDs was strongly associated with the crowding (OR = 1.318, P = 0.007), while the occurrence of the mandibular ABDs was significantly associated with root surface (labial vs. lingual, OR = 1.836, P = 0.008).

Conclusions

The incidence of ABDs/ABFs significantly increased after non-extraction CAT with Class II elastics in adults, especially on the labial root surface of the mandibular anterior teeth. Orthodontists should be well aware of the periodontal risks of CAT with Class II elastics.

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Introduction

Periodontal bone support is of vital importance for long-term periodontal health. Alveolar bone defects can lead to the denudation of tooth roots, where the root surface is covered only by periosteum and gingiva [1, 2]. If the denuded area does not involve the alveolar margin, it is referred to as an alveolar bone fenestration (ABF). And alveolar bone dehiscences (ABDs) are defined as bone defects that involve the alveolar margin [3]. The reported prevalence of ABDs and ABFs in the anterior tooth region varies from 4.2 to 27.46% and 5–26.91%, respectively [4, 5]. Additionally, factors such as orthodontic treatment, age, sagittal skeletal pattern, and crowding may also affect the incidence of ABDs and ABFs [4, 6, 7].

Driven by the demand for aesthetics and comfort, clear aligner therapy (CAT) has gained significant popularity, especially in adult orthodontics. With the extension of the length of aligner tray, CAT has demonstrated great efficacy in the molar distalization and it has even become the primary treatment modality for non-extraction treatment of Class II malocclusion in clinical practice [8, 9].

During the sequential distalization of the maxillary molars in CAT, Class II elastics are often used to reinforce the anchorage to prevent the uncontrolled flaring of the maxillary anterior teeth [10, 11]. However, Class II elastics may lead to several side effects, such as extrusion of the mandibular molars, loss of mandibular anchorage and labial inclination of mandibular incisors [12, 13], potentially increasing the risk of mandibular ABDs/ABFs.

The impacts of Class II elastics on periodontal tissues during fixed orthodontic treatment have been extensively studied. Colet et al. found that fixed appliances combined with Class II elastics did not increase gingival recession [14]. In addition, finite element analyses have demonstrated that appropriate Class II elastics during CAT are effective for anchorage reinforcement and will not cause periodontal damage to the mandibular arch [15, 16]. However, no clinical research has been conducted to investigate the incidence of ABDs/ABFs in patients who receive non-extraction CAT with Class II elastics.

Thus, the purpose of this study was to compare the presence of ABDs/ABFs in the anterior tooth region of adult patients with non-extraction CAT before and after Class II elastics. The authors hypothesized that non-extraction CAT with Class II elastics have no impact on the incidence of ABDs/ABFs in the anterior tooth region of adult patients.

Materials and methods

Ethical approval

This retrospective study was approved by the Ethics Committee at the Nanjing Stomatological Hospital, Affiliated Hospital of Medical School of Nanjing University, (ethical approval No. NJSH-2023NL-036).

Samples

Records of patients who visited the Department of Orthodontics at the Nanjing Stomatological Hospital for orthodontic treatment and had completed orthodontic treatment between January 2020 and June 2024 were retrospectively reviewed. A total of 3186 participants were assessed for eligibility, and finally, 30 adult patients with Class II malocclusion treated by Invisalign® (Align Technology Inc, Santa Clara, Calif) were collected in the present study. Screening flow is shown in Fig. 1. All patients utilized rubber bands (5/16-inch, 3.5 oz) for Class II elastics to reinforce the anchorage. The rubber bands were attached to the precision cutting designed on the maxillary canine and the button bonded on the mandibular first molar. The illustration for Class II elastics is shown in Fig. 2.

Fig. 1
figure 1

Screening flowchart for eligible patients

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The inclusion criteria were as follows: (1) aged > 18 years, (2) ANB angle > 1° and bilateral molar Class II relationships, (3) have completed orthodontic treatment by Invisalign® with Class II elastics, (4) no craniofacial syndromes, (5) no orthodontic treatment or surgical history at craniofacial region, (6) good compliance during the treatment, (7) CBCT of good quality.

The exclusion criteria were as follows: (1) periodontal diseases history such as periodontitis, (2) self-reported smokers, (3) diabetes and other systemic diseases related to periodontal disease, (4) extraction treatment except for third molars, (5) amalgam restorations in root surfaces of teeth leading to scattering radiation.

Fig. 2
figure 2

Illustration for Class II elastics of one of the treated patients. (a) Lateral intraoral view before CAT (T0). (b) Illustration for Class II elastics, rubber band was attached to the precision cutting designed on the maxillary canine and the button bonded on the mandibular first molar. (c) Lateral intraoral view after CAT (T1). d-e. Figures extracted from ClinCheck® (Align Technology, San Josè, California, USA)

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The sample size of the present study was estimated based on a similar study of Allahham et al., which reported a preoperative and postoperative incidence of ABDs in anterior teeth of 39% and 53%, respectively [17]. By using the PASS software (Version 15.0, NCSS, LLC), a sample of 30 subjects would give 80% power (1-β) to detect a significant change in the number of ABDs at the α = 0.05 significance level.

CBCT measurement methods

All patients underwent CBCT scans (NewTom VG, Italy) before (T0) and after (T1) treatment with the following radiological parameters: 110 kV, 25 mA, voxel size of 0.25 mm, 16 cm × 16 cm field of view, exposure time of 20–25 s. According to the imaging protocol, patients were seated and bite into maximum dental intercuspation, when the Frankfort plane was adjusted to be parallel to the ground, the CBCT scans were obtained.

The images were then imported into the Dolphin Imaging 11.9 software (Chatsworth, Calif) in Digital Imaging and Communications in Medicine (DICOM) mode for measurement. All CBCT images were examined based on diagnostic criteria from previous studies to assess the presence of ABDs and ABFs [17,18,19]. The corrected sagittal view was chosen as the measurement plane for ABDs/ABFs, detailed measurement procedures were shown in Fig. 3. Reference points and measurement variables were defined according to previous studies and were shown in Table 1 [20]. The critical point was set at 2 mm for ABDs and 2.2 mm for ABFs. With regard to this, ABDs were recorded when d was > 2 mm, while ABFs were counted when f was > 2.2 mm. The d value, f value and counts of ABDs/ABFs were recorded at the labial and lingual root surfaces of the maxillary and mandibular anterior teeth at T0 and T1. The severity of ABDs/ABFs was classified as: mild ABD (2 < d ≤ 4 mm); moderate ABD (4 < d ≤ 6 mm); severe ABD (d > 6 mm) and mild ABF (2.2 < f ≤ 4 mm); moderate ABF (4 < f ≤ 6 mm); severe ABF (f > 6 mm), respectively [5].

All lateral cephalometric radiographs were reconstructed by utilizing the Build X-Rays Tool, and the following radiographic parameters were assessed: (1) upper incisor inclination, measured as maxillary central incisor inclination to the sella-nasion plane (UI-SN); (2) lower incisor inclination, measured as Incisor Mandibular Plane Angle (IMPA); (3) mandibular plane angle, measured as mandibular plane to sella-nasion plane (MP-SN) angle; (4) ANB angle. All cephalometric landmarks and reference planes/lines are shown in Fig. 4. The pretreatment crowding of anterior tooth region was assessed on the dental arch models, calculated as: Crowding = (required length of the dental arch) - (available length of the dental arch), and crowding > 0 indicates the presence of crowding. Additionally, clinical data such as gender, age and duration of Class II elastics were gathered from patient medical records.

Statistical analysis

Repeated examinations of all measurements were performed two weeks later by the same observer and a second observer. The intraclass correlation coefficient (ICC) was used to assess both intra-observer and inter-observer reliability. Quantitative data were recorded as means and standard deviations (age, Class II elastics duration, ANB angle, U1-SN angle, IMPA, pretreatment crowding of anterior tooth region), and counts (%) were calculated for categorical variables (gender, ABDs, ABFs). The incidence of ABDs/ABFs at T0 versus T1 was compared using the paired chi-square test (McNemar’s test). Binary logistic regression was performed to evaluate the correlation between parameters related to treatment and the presence of ABDs/ABFs in the anterior region at T1. Parameters used in the regression analysis include gender, age, ANB, MP-SN, U1-SN, IMPA, pretreatment crowding, root surface and tooth side. Since only 1 of the 360 anterior teeth exhibited fenestration on the lingual side, and lingual fenestrations are relatively rare in anterior teeth [19], the lingual fenestrations were not analyzed by the binary logistic regression. Statistical significance was set at 0.05. Data analysis was performed with SPSS statistical software (version 25.0; IBM, Armonk, NY).

Fig. 3
figure 3

Detailed measurement procedures for ABDs and ABFs. Red, axial plane; Yellow, sagittal plane; Green, coronal plane. a (axial view), adjust the axial view by making the red line pass through cementoenamel junction (CEJ) in both the coronal and sagittal views, then rotate the yellow line passing through the labiolingual side; b (sagittal view), rotate the green line in the sagittal view to make it pass through the root apex and the incisal edge, and parallel to the long axis of the root; c (coronal view), rotate the yellow line in the coronal view until it passes through the root apex and the midpoint of the incisal margin, and parallel to the long axis of the root; d, The corrected sagittal view was chosen as the measurement plane. For the selected central incisor, both ABD (d-labial = 2.3 mm > 2 mm) and ABF (f-labial = 5.4 mm > 2.3 mm) occurred in the labial side, while ABD (d-lingual = 0.7 mm < 2 mm) and ABF (f-lingual = 0 mm < 2.3 mm) were not detected in the lingual side. The definitions of reference points and variables are shown in Table 1

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Table 1 Definitions of reference points and variables
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Fig. 4
figure 4

Cephalometric landmarks and reference planes/lines

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Results

The intra-observer and inter-observer reliability for all measurements were strong, with ICC all exceeding 0.9 (Supplementary Tables 1–5). In total, a sample of 30 Class II subjects (25 females and 5 males; mean age 26.1 ± 4.4 years) were enrolled in this study. All patients achieved a bilateral Class I molar relationship at T1 and the average Class II elastics duration was 11.7 ± 2.3 months. The pretreatment average crowding of anterior tooth region of the maxilla and mandible was 1.3 ± 1.3 mm and 2.0 ± 1.7 mm, respectively. The pretreatment average ANB angle, MP-SN angle, UI-SN angle, and L1-MP angle were 4.5 ± 1.9°, 34.1 ± 7.6°, 100.4 ± 12.1°, and 95.4 ± 7.4°, respectively.

Comparison of the frequency of ABDs and ABFs between T0 and T1 (Table 2)

Table 2 shows the prevalence of ABDs/ABFs on the labial and lingual sides of different tooth positions at T0 and T1. The paired chi-square test results indicate a significant increase in the overall prevalence of ABDs (28.1% vs. 47.4%, P < 0.001) and ABFs (9.3% vs. 12.8%, P = 0.008) in the anterior alveolar region. The prevalence of ABDs increased significantly on the maxillary labial side (26.1% vs. 41.1%, P < 0.001), maxillary lingual side (10.0% vs. 36.1%, P < 0.001), and mandibular labial side (35.0% vs. 62.8%, P < 0.001), while the prevalence of ABFs increased significantly on the maxillary labial side (18.9% vs. 27.8%, P = 0.023). The graded distribution of ABDs/ABFs for different tooth positions is shown in Fig. 5. It can be seen that after treatment, the incidence of lingual ABDs increased in most maxillary anterior teeth and labial ABDs increased in most mandibular anterior teeth.

Table 2 Prevalence of ABDs/ABFs before and after CAT
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Fig. 5
figure 5

Graded distribution of ABDs/ABFs for different tooth positions; *P < 0.05

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Logistic regression analysis of ABDs after treatment (Table 3)

The presence of the maxillary ABDs at T1 was significantly associated with age (OR = 1.111, P < 0.001), inclination of upper central incisor (OR = 1.024, P = 0.042), crowding of maxillary anterior tooth region (OR = 1.318, P = 0.007) and tooth position (lateral incisor vs. central incisor, OR = 2.856, P = 0.001; canine vs. central incisor, OR = 4.185, P < 0.001). The presence of the mandibular ABDs at T1 was significantly associated with gender (male vs. female, OR = 0.455, P = 0.023), ANB (OR = 1.160, P = 0.042), crowding of mandibular anterior tooth region (OR = 1.163, P = 0.042) and root surface (labial vs. lingual, OR = 1.836, P = 0.008).

Table 3 Associations by logistic regression between parameters and ABDs at T1
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Logistic regression analysis of ABFs after treatment (Table 4)

The presence of the maxillary ABFs at T1 was significantly associated with tooth position (lateral incisor vs. central incisor, OR = 3.094, P = 0.037; canine vs. central incisor, OR = 8.446, P < 0.001; lateral incisor vs. canine, OR = 0.366, P = 0.005), while the presence of the mandibular ABFs at T1 was significantly associated with mandibular plane angle (OR = 1.066, P = 0.037) and inclination of lower central incisor (OR = 1.064, P = 0.044).

Table 4 Associations by logistic regression between parameters and ABFs at T1
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Discussion

This is the first study to explore the effects of CAT with Class II elastics in clinical settings. Research has shown that CBCT is effective in detecting bone defects, with sensitivity and specificity values exceeding 0.7 for the detection of ABDs/ABFs [18]. However, the accuracy of CBCT tends to decrease as the thickness of the alveolar bone decreases. It may overestimate the presence of ABDs/ABFs, particularly when cortical thickness is less than 1 mm [21]. To reduce the occurrence of false positives, this study applied strict diagnostic thresholds for ABDs/ABFs following previous recommendations [17].

At the root surface level, the pretreatment prevalence of ABDs and ABFs in the anterior teeth was 28.1% and 9.3%, respectively. This is lower compared to previous studies that used the same standard based on CBCT [17, 19]. The reasons for this discrepancy may include ethnic differences and variations in malocclusions. The sample included by Allahham et al. was composed entirely of crowded cases, which can increase the incidence of bone defect [17]. Evangelista et al. provided only the overall prevalence data for the full dentition, while specifically, the occurrence of ABFs is rare on the lingual side of the anterior teeth [4, 19].

In this study, there was a significant increase in the total incidence of ABDs (28.1% vs. 47.4%, P < 0.001) and ABFs (9.3% vs. 12.8%, P = 0.008) at T1, contrasting Liu et al.‘s finite element analysis, which indicated that proper Class II elastics can effectively enhance the anchorage of the upper anterior teeth and maintain the mandibular anterior periodontal ligament (PDL) stress within the safe range during the sequential distalization of the upper molars in CAT [16]. The rise in the incidence of ABDs and ABFs might be associated with the confines of the alveolar bone boundaries and the magnitude of tooth movement.

During orthodontic treatment, continuous orthodontic force leads to frontal resorption on the compressed side and bone formation on the tension side, remodeling the alveolar bone [22]. However, the remodeling of the alveolar bone is limited, and the direction and intensity of orthodontic forces influence this remodeling. If tooth movement exceed the limits of alveolar bone remodeling, the occurrence of ABFs/ABDs will be inevitable [23, 24]. Correction of Class II malocclusion often requires significant tooth movement to camouflage the jaw discrepancy, which may cause the teeth to move beyond the boundaries of the alveolar bone, ultimately resulting in ABDs [25]. The present study revealed that significant increases in the incidence of ABDs were predominantly observed on the lingual side of maxillary anterior teeth and labial side of mandibular anterior teeth (Fig. 5). The results also validate this viewpoint. The boundaries of the alveolar bone should be an important consideration in orthodontic treatment.

Patients’ oral hygiene may also be a factor contributing to bone defects. Although some scholars suggest that clear aligners have advantages in maintaining oral hygiene [26, 27], this viewpoint has not reached a consensus [28]. During orthodontic treatment, poor oral hygiene leading to plaque accumulation can exacerbate periodontal inflammation and promote alveolar bone resorption [29]. Meanwhile, the CBCT scans of T1 were taken immediately after treatment, at which time the alveolar bone may not have completely remodeled. Research has shown that the incidence of lingual ABDs and labial ABFs significantly decreased from 67.4 to 11.1% and from 24.3 to 10.4%, respectively, after at least one year of retention following orthodontic retraction of maxillary anterior teeth [30]. Therefore, if it is possible to conduct a follow-up on the subjects several years later, the incidence rate of ABFs/ABDs after treatment may potentially decrease.

Due to the different traction directions and varying influencing factors, separate binary logistic regressions were conducted for the maxilla and mandible. Consistent with previous studies [3, 7], the position of the teeth is significantly associated with the incidence of maxillary ABDs/ABFs at T1, with bone defects more prone to occur in the canines and lateral incisors (Tables 3 and 4). This may be attributed to the thinner alveolar bone plate at the lateral incisor, as well as the masticatory pressure that the canine teeth must withstand [7, 31]. Yoshida et al. have demonstrated that the center of resistance for the six-tooth anterior segment is located adjacent to the lateral incisor [32]. When applying Class II elastics to the arches, stress concentration may occur in the region of the lateral incisors, which could potentially lead to bone defects. Furthermore, the force exerted on the canine during Class II elastics is often linear, which often does not align with the arch’s natural curvature. This mismatch may also lead to the appearance of localized pressure points on the alveolar bone, thereby causing ABDs/ABFs.

With the advancement of age, patients exhibit declining cellular activity and diminished capacity for alveolar bone remodeling, which can lead to an increased incidence of bone defects after orthodontic treatment [33]. This may explain why the advancing age contributes to the occurrence of maxillary ABDs in the present sample (Table 3). Enhos et al. found that the incidence of ABDs in hypo-divergent patients is lower [34], which is consistent with the results of this study (Table 4). In this study, patients with an increased ANB angle are more prone to developing mandibular ABDs. It may be due to the significant tooth movement required to camouflage the jaw discrepancy during the treatment of skeletal Class II malocclusions in adults [25]. Aligned with the research conducted by Luo et al. [4], the binary logistic regression analysis revealed that the risk of mandibular ABDs in males is 0.455 times that of females (Table 4). However, as the majority of the samples in this study are female, the regression model may suffer from sample bias, caution should be exercised when interpreting the effects of gender.

Although U1-SN and IMPA have statistically significant positive effects on the incidence of maxillary ABDs and mandibular ABFs after treatment, their Odds Ratios (OR) are only 1.024 and 1.064, respectively (Tables 3 and 4). This suggests that the impact of incisor inclination before CAT on the occurrence of alveolar bone defect at T1 is relatively limited, which is consistent with the previous study [35]. The binary logistic regression results indicate that the risk of mandibular ABDs on the labial side is 1.836 times greater than that on the lingual side, which may be attributable to the side effect of forward movement of mandibular incisors caused by Class II elastics [12]. In non-extraction CAT, tooth alignment often requires labial movement to relieve crowding, which can increase the risk of ABDs/ABFs [17]. Research has demonstrated that crowded dentition is more susceptible to bone defects [4]. The present study’s results also show that crowding significantly contributes to the increased occurrence of ABDs in the maxilla (OR = 1.318, P = 0.007) and the mandible (OR = 1.163, P = 0.042) (Table 3).

In conclusion, after the use of Class II elastics, the incidence of ABDs/ABFs in the anterior region of adult non-extraction CAT patients significantly increased. Therefore, the authors suggest that Class II elastics should be approached with caution in CAT. At the same time, during the treatment, close attention should be paid to the patients’ periodontal condition, and if necessary, periodontal accelerated osteogenic orthodontics (PAOO) can be used to prevent the occurrence of ABDs/ABFs and promote alveolar bone augmentation [36, 37].

Limitation

This study also has limitations: CBCT may overestimate the incidence of ABDs/ABFs, especially when cortical thickness is less than 1 mm, and the lack of long-term follow-up to assess alveolar remodeling could further exaggerate these values. The regional selection bias may limit the generalizability of the findings to other populations with diverse genetic backgrounds or clinical protocols. The relatively small sample size may reduce statistical power and increase the risk of Type II errors. Due to radiation exposure and ethical constraints, researchers could not obtain immediate CBCT scans after the completion of Class II elastics, potentially resulting in confounding factors affecting ABDs/ABFs results. Further research with larger cohorts and long-term follow-up is needed to validate the findings and evaluate the long-term effects of Class II elastics. Additionally, a control group with temporary anchorage devices (TADs) could be established to clarify whether Class II elastics has an impact on the incidence of ABDs/ABFs in the mandibular anterior teeth.

Conclusion

  1. 1.

    The incidence of ABDs/ABFs significantly increased after Class II elastics treatment in adult non-extraction clear aligner therapy.

  2. 2.

    Risk factors for ABDs/ABFs include female gender, advanced age, the lingual root surface, the tooth position of the canine and the lateral incisor, as well as an increased MP-SN angle, ANB angle, inclination of the upper and lower central incisors, and crowding of the dentition.

Data availability

The datasets supporting the conclusions of this article are included within the article and its additional files. The raw de-identified data are available from the corresponding author on reasonable request.

Abbreviations

CBCT:

Cone beam computed tomography

ABDs:

Alveolar bone dehiscences

ABFs:

Alveolar bone fenestrations

CAT:

Clear aligner therapy

ANB:

A point-Nasion-B point angle

MP-SN:

Mandibular plane to sella-nasion plane

DICOM:

Digital Imaging and Communications in Medicine

UI-SN:

Maxillary central incisor inclination to the sella-nasion plane

FMIA:

Frankfort mandibular incisal angle

ICC:

Intra-class correlation coefficients

PDL:

periodontal ligament

PAOO:

periodontal accelerated osteogenic orthodontics

References

  1. Leung CC, Palomo L, Griffith R, Hans MG. Accuracy and reliability of cone-beam computed tomography for measuring alveolar bone height and detecting bony dehiscences and fenestrations. Am J Orthod Dentofac Orthop. 2010;137(4 Suppl):S109–119.

    Article  Google Scholar 

  2. Edel A. Alveolar bone fenestrations and dehiscences in dry bedouin jaws. J Clin Periodontol. 1981;8(6):491–9.

    Article  CAS  PubMed  Google Scholar 

  3. Davies RM, Downer MC, Hull PS, Lennon MA. Alveolar defects in human skulls. J Clin Periodontol. 1974;1(2):107–11.

    Article  CAS  PubMed  Google Scholar 

  4. Luo N, Chen Y, Li L, Wu Y, Dai H, Zhou J. Multivariate analysis of alveolar bone dehiscence and fenestration in anterior teeth after orthodontic treatment: A retrospective study. Orthod Craniofac Res. 2024;27(2):287–96.

    Article  PubMed  Google Scholar 

  5. Sun L, Mu C, Chen L, Zhao B, Pan J, Liu Y. Dehiscence and fenestration of class I individuals with normality patterns in the anterior region: a CBCT study. Clin Oral Investig. 2022;26(5):4137–45.

    Article  PubMed  PubMed Central  Google Scholar 

  6. Coşkun İ, Kaya B. Appraisal of the relationship between tooth inclination, dehiscence, fenestration, and sagittal skeletal pattern with cone beam computed tomography. Angle Orthod. 2019;89(4):544–51.

    Article  PubMed  PubMed Central  Google Scholar 

  7. Jing WD, Xu L, Li XT, Xu X, Jiao J, Hou JX, Wang XX. Prevalence of and risk factors for alveolar fenestration and dehiscence in the anterior teeth of Chinese patients with skeletal class III malocclusion. Am J Orthod Dentofac Orthop. 2021;159(3):312–20.

    Article  Google Scholar 

  8. Lombardo L, Colonna A, Carlucci A, Oliverio T, Siciliani G. Class II subdivision correction with clear aligners using intermaxilary elastics. Prog Orthod. 2018;19(1):32.

    Article  PubMed  PubMed Central  Google Scholar 

  9. Kuo E, Miller RJ. Automated custom-manufacturing technology in orthodontics. Am J Orthod Dentofac Orthop. 2003;123(5):578–81.

    Article  Google Scholar 

  10. Al-Tayar B, Al-Somairi MAA, LH AL, Wang X, Wang J, Liu J, Al-Tayar B, An X, Si Q. Impact of molar teeth distalization by clear aligners on temporomandibular joint: a three-dimensional study. Prog Orthod. 2023;24(1):25.

    Article  PubMed  PubMed Central  Google Scholar 

  11. Ravera S, Castroflorio T, Garino F, Daher S, Cugliari G, Deregibus A. Maxillary molar distalization with aligners in adult patients: a multicenter retrospective study. Prog Orthod. 2016;17:12.

    Article  PubMed  PubMed Central  Google Scholar 

  12. Janson G, Sathler R, Fernandes TM, Branco NC, Freitas MR. Correction of class II malocclusion with class II elastics: a systematic review. Am J Orthod Dentofac Orthop. 2013;143(3):383–92.

    Article  Google Scholar 

  13. Ellen EK, Schneider BJ, Sellke T. A comparative study of anchorage in bioprogressive versus standard Edgewise treatment in class II correction with intermaxillary elastic force. Am J Orthod Dentofac Orthop. 1998;114(4):430–6.

    Article  CAS  Google Scholar 

  14. Colet R, Cotrin P, Oliveira RC, Valarelli FP, Gobbi de Oliveira RC, Salmeron S, Freitas KMS. Gingival recession in mandibular anterior teeth in patients with class II malocclusion treated with elastics and twin force appliance. Am J Orthod Dentofac Orthop. 2022;162(4):529–37.

    Article  Google Scholar 

  15. Wang Q, Dai D, Wang J, Chen Y, Zhang C. Biomechanical analysis of effective mandibular en-masse Retraction using class II elastics with a clear aligner: a finite element study. Prog Orthod. 2022;23(1):23.

    Article  PubMed  PubMed Central  Google Scholar 

  16. Liu X, Cheng Y, Qin W, Fang S, Wang W, Ma Y, Jin Z. Effects of upper-molar distalization using clear aligners in combination with class II elastics: a three-dimensional finite element analysis. BMC Oral Health. 2022;22(1):546.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  17. Allahham DO, Kotsailidi EA, Barmak AB, Rossouw PE, El-Bialy T, Michelogiannakis D. Association between nonextraction clear aligner therapy and alveolar bone dehiscences and fenestrations in adults with mild-to-moderate crowding. Am J Orthod Dentofac Orthop. 2023;163(1):22–e3224.

    Article  Google Scholar 

  18. Sun L, Zhang L, Shen G, Wang B, Fang B. Accuracy of cone-beam computed tomography in detecting alveolar bone dehiscences and fenestrations. Am J Orthod Dentofac Orthop. 2015;147(3):313–23.

    Article  Google Scholar 

  19. Evangelista K, Vasconcelos KF, Bumann A, Hirsch E, Nitka M, Silva MA. Dehiscence and fenestration in patients with class I and class II division 1 malocclusion assessed with cone-beam computed tomography. Am J Orthod Dentofac Orthop. 2010;138(2):e133131–137. discussion 133-135.

    Article  Google Scholar 

  20. Sun L, Yuan L, Wang B, Zhang L, Shen G, Fang B. Changes of alveolar bone dehiscence and fenestration after augmented corticotomy-assisted orthodontic treatment: a CBCT evaluation. Prog Orthod. 2019;20(1):7.

    Article  PubMed  PubMed Central  Google Scholar 

  21. Peterson AG, Wang M, Gonzalez S, Covell DA Jr., Katancik J, Sehgal HS. An in vivo and cone beam computed tomography investigation of the accuracy in measuring alveolar bone height and detecting dehiscence and fenestration defects. Int J Oral Maxillofac Implants. 2018;33(6):1296–304.

    Article  PubMed  Google Scholar 

  22. Krishnan V, Davidovitch Z. Cellular, molecular, and tissue-level reactions to orthodontic force. Am J Orthod Dentofac Orthop. 2006;129(4):e469461–432.

    Article  Google Scholar 

  23. Choi YJ, Chung CJ, Kim KH. Periodontal consequences of mandibular incisor proclination during presurgical orthodontic treatment in class III malocclusion patients. Angle Orthod. 2015;85(3):427–33.

    Article  PubMed  Google Scholar 

  24. Ramos AL, Dos Santos MC, de Almeida MR, Mir CF. Bone dehiscence formation during orthodontic tooth movement through atrophic alveolar ridges. Angle Orthod. 2020;90(3):321–9.

    Article  PubMed  Google Scholar 

  25. Pontes LF, Maia FA, Almeida MR, Flores-Mir C, Normando D. Mandibular Protraction appliance effects in class II malocclusion in children, adolescents and young adults. Braz Dent J. 2017;28(2):225–33.

    Article  PubMed  Google Scholar 

  26. Lu H, Tang H, Zhou T, Kang N. Assessment of the periodontal health status in patients undergoing orthodontic treatment with fixed appliances and invisalign system: A meta-analysis. Med (Baltim). 2018;97(13):e0248.

    Article  CAS  Google Scholar 

  27. Rossini G, Parrini S, Castroflorio T, Deregibus A, Debernardi CL. Periodontal health during clear aligners treatment: a systematic review. Eur J Orthod. 2015;37(5):539–43.

    Article  PubMed  Google Scholar 

  28. Chhibber A, Agarwal S, Yadav S, Kuo CL, Upadhyay M. Which orthodontic appliance is best for oral hygiene? A randomized clinical trial. Am J Orthod Dentofac Orthop. 2018;153(2):175–83.

    Article  Google Scholar 

  29. Luchian I, Surlari Z, Goriuc A, Ioanid N, Zetu I, Butnaru O, Scutariu MM, Tatarciuc M, Budala DG. The influence of orthodontic treatment on periodontal health between challenge and synergy: A narrative review. Dent J (Basel) 2024, 12(4).

  30. Guo R, Li L, Lin Y, Huang Y, Liu J, Pan M, Xu L, Li W. Long-term bone remodeling of maxillary anterior teeth with post-treatment alveolar bone defect in adult patients with maxillary protrusion: a prospective follow-up study. Prog Orthod. 2023;24(1):36.

    Article  PubMed  PubMed Central  Google Scholar 

  31. Tsigarida A, Toscano J, de Brito Bezerra B, Geminiani A, Barmak AB, Caton J, Papaspyridakos P, Chochlidakis K. Buccal bone thickness of maxillary anterior teeth: A systematic review and meta-analysis. J Clin Periodontol. 2020;47(11):1326–43.

    Article  PubMed  Google Scholar 

  32. Yoshida N, Koga Y, Mimaki N, Kobayashi K. In vivo determination of the centres of resistance of maxillary anterior teeth subjected to Retraction forces. Eur J Orthod. 2001;23(5):529–34.

    Article  CAS  PubMed  Google Scholar 

  33. Kuc AE, Kotuła J, Nawrocki J, Kulgawczyk M, Kawala B, Lis J, Sarul M. Bone remodeling of maxilla after Retraction of incisors during orthodontic treatment with extraction of premolars based on CBCT study: A systematic review. J Clin Med 2024, 13(5).

  34. Enhos S, Uysal T, Yagci A, Veli İ, Ucar FI, Ozer T. Dehiscence and fenestration in patients with different vertical growth patterns assessed with cone-beam computed tomography. Angle Orthod. 2012;82(5):868–74.

    Article  PubMed  PubMed Central  Google Scholar 

  35. Dalaie K, Hajimiresmail YS, Safi Y, Baghban AA, Behnaz M, Rafsanjan KT. Correlation of alveolar bone thickness and central incisor inclination in skeletal class I and II malocclusions with different vertical skeletal patterns: A CBCT study. Am J Orthod Dentofac Orthop. 2023;164(4):537–44.

    Article  Google Scholar 

  36. Murphy KG, Wilcko MT, Wilcko WM, Ferguson DJ. Periodontal accelerated osteogenic orthodontics: a description of the surgical technique. J Oral Maxillofac Surg. 2009;67(10):2160–6.

    Article  PubMed  Google Scholar 

  37. Miyamoto T, Lang M, Khan S, Kumagai K, Nunn ME. The clinical efficacy of deproteinized bovine bone mineral with 10% collagen in conjunction with localized piezosurgical decortication enhanced orthodontics: A prospective observational study. J Periodontol. 2019;90(10):1106–15.

    Article  CAS  PubMed  Google Scholar 

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Acknowledgements

Not applicable.

Funding

This work was supported by the Natural Science Foundation of China (number 82371007), High-Level Hospital Construction Project of Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Institute of Stomatology, Nanjing University(0224C015), and the China Oral Health Foundation-Smiling Children (Adolescent growth and oral health prevention and treatment) Grant(A2023-001).

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Authors and Affiliations

  1. Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Institute of Stomatology, Nanjing University, Nanjing, China

    Chenxu Wang, Yang Zhao & Feng Guo

  2. Department of Periodontics, Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Institute of Stomatology, Nanjing University, Nanjing, China

    Houxuan Li

  3. Department of Orthodontics, Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Institute of Stomatology, Nanjing University, Nanjing, China

    Lang Lei

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  1. Chenxu Wang
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  2. Yang Zhao
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  3. Feng Guo
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Contributions

CW: Study conception and design; curation and analysis of data; and drafting of the manuscript. YZ: Curation and analysis of data; revision of the manuscript. FG: Software; revision of the manuscript. HL: Conceptualization; project administration; resources; supervision; critical revision of the manuscript. LL: Conceptualization; project administration; resources; supervision; critical revision of the manuscript.

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Correspondence to Houxuan Li or Lang Lei.

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Ethics approval and consent to participate

All experiments were performed in accordance with Declaration of Helsinki. Ethical approval for this retrospective study was granted by the Ethics Committee at the Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Research Institute of Stomatology, Nanjing University, Nanjing, China [approval No. NJSH-2023NL-036]. Informed consent for the anonymous use of patient data was obtained from all individual participants included in the study.

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The authors declare no competing interests.

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Wang, C., Zhao, Y., Guo, F. et al. Incidence and risk factors of alveolar bone dehiscences and fenestrations after clear aligner therapy with Class II elastics: a retrospective study. BMC Oral Health 25, 644 (2025). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12903-025-06023-0

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Keywords

BMC Oral Health

ISSN: 1472-6831

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