Changes of vertical dimension and alveolar bone remodeling in patients with second molar scissors bite during orthodontic correction

doi:10.21203/rs.3.rs-4878388/v1

The aims of this retrospective study were to assess changes of vertical dimension and alveolar bone remodeling in cases with second molar scissors bite (SB) before and after intermaxillary cross-elastics (ICE) treatment. 36 patients with unilateral SB (SB group) and 36 subjects with normal occlusion (Control group) were included. CBCT records were taken before (SB-T0) and after orthodontic treatment (SB-T1). Alveolar bone height (ABH) and thickness (ABT), tooth and alveolar bone inclination, molar and facial height were measured. No changes on the vertical dimension were observed during treatment. Surrounding alveolar bone displayed synchronous changes in the inclination with molars for both arches. After ICE, the maxillary alveolar bone was found thinner at buccal side (P < 0.05), while no difference was found at the palatal side. The mandibular alveolar bone was found thicker at buccal side and thinner at lingual side (P < 0.05). Nevertheless, no difference in the alveolar bone thickness was observed between SB-T1 group and Control group. ICE is a safe method to correct SB with stability of vertical dimension and safety of periodontal bone. Buccolingual inclination of the alveolar bone changes with the molar tooth movement, showing a bone bending tendency during SB correction.

Health sciences/Diseases/Dental diseases

Health sciences/Health care/Dentistry/Dental treatments

Health sciences/Health care/Dentistry/Orthodontics

CBCT

scissors bite

intermaxillary cross-elastics treatment

vertical dimension

bone remodeling

Scissors bite (SB), a malocclusion with maxillary teeth occluding outside the mandibular arch in the intercuspal position, is very common at the second molars in the orthodontic clinic.¹ The SB of the second molars may interfere with lateral excursion during mastication, leading to masticatory dysfunction, temporomandibular joint disorders and periodontal destruction.^2–4 Several approaches, including intermaxillary cross elastics (ICE), modified palatal arch, temporary anchorage devices (TADs), and orthognathic surgery, have been proposed to correct SB of the posterior teeth.^5–7 Thanks to the simplicity of clinical operation, ICE is the most commonly used method.⁸

Molar overeruption is common in second molars with SB due to loss of antagonism from opponent teeth. The vertical component of the intermaxillary traction may further extrude over-erupted molars with SB, leading to a vertical issue, especially in patients with a hyperdivergent facial growth pattern.⁹ However, the vertical dimension of a human face is not determined by the teeth, but primarily by facial muscles, especially the digastric, masseter and temporalis musles.¹⁰ According to Spyropoulos MN and Askarieh M, patients tend to resist unexpected extrusive forces by facial muscles and maintain the vertical dimension.¹¹ Therefore, the overeruption and extrusion during SB correction by ICE may be counteracted by the muscle activity. However, currently, no information is available regarding the effect of ICE on SB during orthodontic tooth movement.

Another major concern in correcting SB is the status of dentoalveolar bone surrounding the molars, since large amount of tooth movement in the buccal-palatal as well as occlusal-gingival direction is finished in a short period. Classically, orthodontic tooth movement is accompanied by bone apposition on the tension side and bone resorption on the compression side,¹² and loss of alveolar bone width at the gingival third on the palatal side of maxillary molars might be anticipated. On the other hand, alveolar bone might be deformed by bending, especially for pediatric patients.¹³ Despite a wide range of reports regarding alveolar bone remodeling in the anterior segment during incisor retraction and posterior segment during arch expansion,^14,15 no report has been found regarding alveolar bone changes during SB correction.

Therefore, the purposes of this study include: (1) exploring changes of vertical dimension in correcting SB; and (2) assessing remodeling of surrounding alveolar bone between patients with SB before and after ICE treatment.

Subjects. The sample size was estimated based on a similar study by Hu et al., in which a standard deviation of 0.58 mm of buccal alveolar bone thickness of maxillary posterior teeth at 3 mm apical to the enamelo-cemental junction (CEJ) was reported.¹⁶ If 0.45 mm was set as clinically significant difference, the sample size was supposed to be 36 patients with a significance level (α) of 0.05 and a statistical power (1 - β) of 90%. The calculation was conducted with the PASS software (Version 21.0.3; NCSS, LLC).

The records of 36 patients with unilateral second molar SB (14 males, 22 females; average age, 24.11 ± 3.72 years old) and 36 adults with normal occlusion (8 males, 28 females; average age, 24.00 ± 3.29 years old) were selected. They were divided into SB group and Control group, respectively. The inclusion criteria of SB group were as follows: (1) Age over 18 years old; (2) No missing teeth except the third molar; (3) SB involving at least one pair of second molars. The inclusion criteria of Control group were as follows: (1) Age over 18 years old; (2) No missing teeth except the third molar; (3) Angle class I with normal alignment in the posterior segment; (4) Normal posterior overjet and overbite in the intercuspal position. The exclusion criteria of two groups included: (1) History of orthodontic treatment; (2) CBCT data with artifacts or distortion; (3) Tooth defect, crown restoration or moderate or severe periodontitis with the measuring tooth.

ICE design and treatment progress. In this study, SB was corrected before placement of brackets to reduce overall discomfort and retain muscle activity. Before ICE treatment, mandibular thermoplastic retainer without SB area was made. Based on the retainer, self-curing denture acrylic was constructed on bilateral posterior segments to serve as a removable bite turbo, thus increasing the interocclusal space to allow SB correction. Two buttons were bonded on the buccal side of maxillary second molar and lingual side of mandibular second molar, respectively. The mechanic of SB correction was 3 cross-elastics (3/16-inch 3.5 oz; Ormco Corporation, USA) applied on the malpositioned molars. Patients were advised to change the elastics daily with a monthly follow-up visit. Once SB molars had nearly normal occlusal contact, the patients were instructed to stop wearing removable bite turbos, wear one elastic at night to retain the correction, and do masticatory exercises by clenching their molars as hard as possible for 15 seconds for 3 times as suggested.¹⁷ After one-month masticatory training, routine orthodontic treatment was initiated.

CBCT protocol and measurements. CBCT scans were conducted for each patient before and after the comprehensive orthodontic treatment, which encompassed both SB correction and other routine orthodontic procedures. All CBCT data was achieved with NNT Viewer software (version 9.0) from October 2016 to August 2023. The settings are as follows: 16 cm×16 cm field of view, 110kV, 25mA, axial slice thickness of 0.25 mm, exposure time of 20–25 seconds for all subjects. All images were reconstructed with Dolphin Imaging software (version 11.95; Dolphin Imaging and Management Solutions, Chatsworth, Calif). To standardize the process of measuring, the orientation of head position for each subject was performed based on Frankfort plane.¹⁶

All cephalometric measurements are shown in Fig. 1, including FMA, SN-GoGn, facial height (N-Me), upper anterior facial height (N-ANS), lower anterior facial height (ANS-Me), posterior facial height (S-Go) and facial height ratio (ANS-Me / N-Me).

To further explore the vertical control after ICE, molar height was measured based on CBCT according to previous studies.^18,19 Two reference planes were used: (1) for the upper molars, the palatal plane (projecting a line through Anterior Nasal Spine and Posterior Nasal Spine) was applied; (2) for the lower molars, the mandibular plane (projecting a line between Gonion and menton points) was applied.¹⁹ The vertical distance between cusps and reference planes were recorded before and after ICE treatment (Fig. 2A,B).

Long axis of tooth and alveolar body were defined according to previous studies.^20,21 The angle from long axis of tooth and alveolar body to a vertical line that was perpendicular to the Frankfort plane were defined as inclination of tooth (In-T) and bone (In-B), respectively (Fig. 2C-F). If the tooth or alveolar body was buccally inclined, the angle would be positive (+), otherwise, the angle would be negative (-). The buccal and lingual ABT at 4 mm, 6 mm, 8 mm apical to CEJ were measured according to Hu’s study.¹⁶ Vertical distance between buccal and lingual alveolar bone crest to CEJ were defined as B-ABH and L-ABH. The measurement of ABH and ABT are described in Fig. 3. If the measurement plane is above the lowest point of maxillary sinus, ABT at this level would be recorded as not available.

Statistical analysis. The reproducibility of measuring procedure was verified by reperforming all measurement of 20 patients at two-week intervals, randomly chosen from two groups, and utilizing intraclass correlation coefficients (ICC) test with confidence level set at 95%. Shapiro-Wilk test was applied for normality of the data and all measures demonstrates normally distributed. Therefore, the measuring values were presented as mean and standard deviation. Independent t test was used to analyze the differences between SB group and Control group, while differences between SB-T0 and SB-T1 were analyzed with paired t test. Missing values were filled with mean value when comparing SB-T1 and Control group. All statistically significant tests were two-sided, computed by using SPSS software (version 23; IBM, Armonk, NY). The significance level was set at 0.05.

Ethics approval and consent to participate. All patients’ data in this study were collected from Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Research Institute of Stomatology, Nanjing University. The study was approved by Institutional Ethics Committee and the approval number is NJSH-2023NL-082-1. All subjects signed informed consent forms.

Approval for human experiments. The study protocol was evaluated and approved by the local ethics committee (Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Research Institute of Stomatology, Nanjing University, NJSH-2023NL-082-1). Written consent was obtained from participants. All subjects signed informed consent forms. Additionally, this study follows the recommendations proposed by the CONSORT Statement.

1. We identify the institutional and/or licensing committee that approved the experiments, including any relevant details.

2. We confirm that all experiments were performed in accordance with relevant named guidelines and regula- tions.

3. We confirm that informed consent was obtained from all participants and/or their legal guardians.

The intraclass correlation coefficient (ICC) values ranged from 0.917 to 0.979, demonstrating acceptable reproducibility of the measurements (Table 1).

Vertical dimension. In the SB-T0 group, patients presented an overall facial type of average mandibular plane angle, with mean SN-GoGn value of 31.20 ± 6.90°. The average duration of ICE treatment was 3.2 months. No statistical difference was found for cephalometric variables on vertical dimension between SB-T0 and SB-T1, including all angular and linear measurements (Table 2). Molar height based on buccal and lingual cusps were further analyzed. A significant intrusion of maxillary palatal cusps (0.85 ± 1.20 mm; P <0.001) and mandibular buccal cusps (0.68 ± 1.22 mm; P <0.01) were observed, indicating pleasant vertical control with intruded SB molars (Table 2).

Maxillary ABH, ABT and inclination. The intragroup comparison of maxillary ABH showed a 0.59 ± 1.03 mm decrease on the buccal side after ICE (P <0.01), from 1.44 ± 0.68 mm (SB-T0) to 2.03 ± 0.85 mm (SB-T1). In SB-T1 group, the buccolingual inclination of maxillary second molar significantly decreased for 15.01 ± 7.67° after ICE treatment (P <0.001), showing no statistical difference with that in Control group (Table 3). Interestingly, the buccolingual inclination of maxillary alveolar bone, buccally inclined in SB-T0, declined significantly (P <0.001) to the same angle of Control group (Table 3). Furthermore, we analyzed the maxillary alveolar bone thickness on both buccal and palatal sides. In SB-T1, the maxillary second molar showed significantly thinner alveolar bone on buccal side than that in SB-T0 at all measuring levels (P <0.01). However, no significant difference was determined for palatal ABT. When comparing SB-T1 with Control group, the buccal and palatal ABT showed no difference as well (Table 3).

Mandibular ABH, ABT and inclination. For mandibular second molars, a significant 0.55 ± 0.83 mm decrease on the lingual side (P <0.001) was found for ABH, from 1.52 ± 0.69 mm (SB-T0) to 2.07 ± 0.74 mm (SB-T1). In SB-T1 group, the mandibular second molar presented an average of 17.17 ± 10.26° of buccal inclination than SB-T0 (P <0.001) and showed no difference with that in control group (Table 4). Similar to maxilla, synchronous inclination with mandibular second molars for the mandible was found. The buccolingual inclination of mandibular alveolar bone, lingully inclined in SB-T0, showed an average of 2.38 ± 1.89° increase significantly (P <0.001) and no difference between SB-T1 and Control group was determined (Table 4). In SB-T1, the buccal ABT of mandibular second molar was thicker at three measuring levels than those in SB-T0 (P <0.05). In contrast, a significant decrease of lingual ABT of mandibular second molar at all measuring levels was found compared with those observed before ICE (P <0.05). When comparing SB-T1 with Control group, the buccal and lingual ABT showed no difference (Table 4).

Despite a wide application of TADs in the correction of unilateral SB in case reports,^22,23 the correction of SB in one single molar by TADs is less common. One possible explanation is that insertion of TADs between the first and second maxillary molars and orthodontic force from the TADs may tilt the second molar mesially. In addition, the difficulty during the placement and discomfort after placement may also hinder the clinician’s choice. The modified transpalatal arch with a hook arm extending to palatal side of the second molar with SB has been proposed in an effort to provide both vertical intrusion and palatal retraction.⁵ However, the effectiveness in the vertical control is questionable in terms of the tooth-supported nature.

Maintaining vertical dimension is of great importance to prevent clockwise rotation of the mandible and deterioration of the profile in patients with a skeletal class II tendency, especially hyperdivergent facial pattern. Muscle force is believed to be the key factor in controlling vertical facial height;^10,24 however, long-term changes in the vertical dimension by denture placement or orthodontic extrusion of molar teeth may trigger a neuromuscular response to establish an adaptation to the altered vertical dimension.^10,25

Bearing in mind the determinant but adaptive role of muscle force in the vertical dimension, we corrected SB at the beginning of treatment in a short time of around 3 months, and placement of braces on the front teeth was delayed to minimize the pain and discomfort and maximize the muscle activity. The removable bite turbo was stopped once SB was corrected and muscle exercises were instructed to intrude the second molars. Satisfactory vertical control with no significant change of facial height was found during correction of SB with ICE in our present research. However, special care is needed in high angle patients who suffer from easy molar extrusion due to the weak musculature.^26,27 Moreover, considering the long duration of facial vertical growth, the growth pattern would be altered by ICE treatment for growing patients.²⁸

Currently, it is still controversary about the nature of orthodontic tooth movement, i.e. whether the teeth move with or through the bone.²⁹ In our current study, only minor loss of alveolar bone width at the buccal side of maxillary second molar and lingual side of the mandibular second molar. Such phenomenon cannot be fully explained by the bone apposition on the tension side and bone resorption on the pressure side theory. Moreover, we observed a 4.01 and 2.38 degree of decrease in the maxillary and mandibular alveolar bone, respectively, showing that a kind of bone bending occurred during SB correction.

Multiple factors, including the force magnitude, tooth movement speed, movement type and patient age, affect periodontal bone support after orthodontic treatment.³⁰ Alveolar bone is far more flexible in young patients than adults, resulting correction of incisor cross bite in a very short time in young children, and this phenomenon supports the bone bending theory.¹³ Alveolar bone density may be less rigid in second molars with SB due to a lack of normal function; therefore, ICE with 3 elastics generate a force of nearly 300 g, equivalent to an orthopedic force, resulting in the formation of hyaline zone in the pressure side and bending of the alveolar bone.

Periodontal bone support is of great importance to periodontal health. We observed around 0.6 mm increase of alveolar bone loss on the buccal side of maxillary second molars and lingual side of mandibular second molars. Alveolar bone loss during orthodontic tooth movement is very common, especially in teeth that undergo extensive movement during incisor retraction and molar mesialization.^31,32 In addition, poor oral hygiene may contribute to worsened periodontal status in patients receiving orthodontic treatment.¹² Moreover, tipping movement was reported to cause more cervical bone resorption than bodily movement.³³ Therefore, clinicians should pay great attention to the periodontal risk in teeth with periodontal health problems.

Although morphologic tendencies and changes of vertical control achieved by ICE were preliminary discussed, there are some limitations of this study. Since hyperdivergent patients tend to have a higher risk of molar extrusion and clockwise mandible rotation,^26,27 vertical control based on different skeletal patterns should be further studied. Besides, the lack of immediate post-ICE evaluation might conceal the potential effects caused by subsequent orthodontic treatment. Therefore, prospective study design might be expected in future investigations.

In conclusion, intermaxillary cross-elastics is an effective treatment to correct second molar scissors bite, presenting a favorable control in vertical dimension. For maxilla, alveolar bone remodeling is characterized by “through the bone” on the buccal side, yet “with the bone” on the palatal side. Besides, surrounding alveolar bone displayed synchronous inclination with scissors bite molars, indicating bone deformation of bending during scissors bite correction.

Competing interests

The authors declare no competing interests.

Additional information

Correspondence and requests for materials should be addressed to L.L.

Author Contribution

F.G. contributed to conceptualization, methodology, software, data curation, original and draft preparation, and editing; C.X.W. and H.Y.H. contributed to data curation; L.L. contributed to project administration, resources, methodology, supervision, and manuscript review and editing. All authors reviewed the manuscript.

Acknowledgements

This study was supported by Natural Science Foundation of China (82371007), and the China Oral Health Foundation-Smiling Children (Adolescent growth and oral health prevention and treatment) Grant. There is no potential conflicts of interest in this study.

Data Availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

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Table 1. Intraclass correlation coefficient (ICC) of maxillary and mandibular measurements for intra-observer reliability. B-ABH, buccal alveolar bone height; L-ABH, lingual alveolar bone height; In-T, buccolingual inclination of tooth; In-B, buccolingual inclination of the alveolar bone; MB, mesiobuccal root; DB, distobuccal root; P, palatal root; ML, mesiolingual root; DL, distolingual root.

Measurement	Maxillary second molar		Mandibular second molar
B-ABH		0.947		0.973
L-ABH		0.954		0.933
In-T		0.939		0.941
In-B		0.917		0.937
4 mm level	MB	0.964	MB	0.963
	DB	0.972	DB	0.976
	P	0.952	ML	0.945
			DL	0.977
6 mm level	MB	0.965	MB	0.950
	DB	0.966	DB	0.979
	P	0.953	ML	0.951
			DL	0.969
8 mm level	MB	0.966	MB	0.960
	DB	0.973	DB	0.968
	P	0.963	ML	0.941
			DL	0.968

Table 2. Comparison on vertical dimension and molar height between SB-T0 group and SB-T1 group. Data are presented as mean ± standard deviation. U7H-B, Upper second molar height based on mesiobuccal cusps; U7H-P, Upper second molar height based on mesiopalatal cusps; L7H-B, Lower second molar height based on mesiobuccal cusps; L7H-B, Lower second molar height based on mesiolingual cusps.

Measurement	SB-T0	SB-T1	T1-T0	P value
FMA (°)	25.88 ± 6.77	26.01 ± 6.72	0.13 ± 1.28	0.552
SN-GoGn (°)	31.20 ± 6.90	31.35 ± 7.00	0.15 ± 1.14	0.435
N-Me (mm)	114.23 ± 7.49	114.05 ± 7.57	-0.18 ± 1.40	0.444
N-ANS (mm)	52.63 ± 3.88	52.41 ± 3.99	-0.22 ± 0.89	0.149
ANS-Me (mm)	60.99 ± 4.77	61.08 ± 4.63	0.09 ± 1.17	0.632
S-Go (mm)	82.88 ± 7.18	82.86 ± 7.61	-0.02 ± 1.28	0.938
ANS-Me/ N-Me (%)	53.37 ± 1.77	53.55 ± 1.76	0.18 ± 0.71	0.137
U7H-B (mm)	18.52 ± 3.65	20.17 ± 2.87	1.65 ± 1.95	0.000
U7H-P (mm)	21.96 ± 2.90	21.11 ± 2.62	-0.85 ± 1.20	0.000
L7H-B (mm)	30.76 ± 3.22	30.08 ± 3.02	-0.68 ± 1.22	0.002
L7H-L (mm)	27.17 ± 4.23	28.95 ± 3.51	1.78 ± 1.94	0.000

Table 3. Comparison of maxillary measurements among the three groups. Data are presented as mean ± standard deviation. B-ABH, buccal alveolar bone height; L-ABH, lingual alveolar bone height; In-T, buccolingual inclination of tooth; In-B, buccolingual inclination of the alveolar bone; MB, mesiobuccal root; DB, distobuccal root; P, palatal root; NA, none available. Results of P value of each measurement were divided into two columns. The first column (P1) presented the results of comparison between SB-T0 group and SB-T1 group, whereas the second column (P2) presented the results of comparison between SB-T1 group and Control group.

Measurement		SB-T0	SB-T1	Control group	T1-T0	P1	P2
B-ABH (mm)		1.44 ± 0.68	2.03 ± 0.85	1.42 ± 0.55	0.59 ± 1.03	0.002	0.001
L-ABH (mm)		1.99 ± 0.60	2.22 ± 0.91	1.87 ± 0.54	0.23 ± 0.98	0.178	0.054
In-T (°)		22.32 ± 8.88	7.31 ± 7.37	7.09 ± 6.93	-15.01 ± 7.67	0.000	0.894
In-B (°)		3.61 ± 6.28	-0.41 ± 6.19	1.00 ± 5.64	-4.01 ± 5.33	0.000	0.317
4 mm	MB (mm)	3.11 ± 1.29	2.46 ± 1.00	2.85 ± 0.74	-0.65 ± 1.23	0.003	0.064
	DB (mm)	3.61 ± 1.33	2.71 ± 1.03	2.76 ± 0.98	-0.89 ± 1.07	0.000	0.852
	P (mm)	1.61 ± 0.57	1.68 ± 0.88	1.93 ± 0.97	0.07 ± 0.96	0.679	0.246
6 mm	MB (mm)	3.96 ± 1.67	3.22 ± 1.19	3.39 ± 1.28	-0.75 ± 1.37	0.002	0.543
	DB (mm)	4.09 ± 1.64	3.09 ± 1.35	2.90 ± 1.31	-1.00 ± 1.07	0.000	0.542
	P (mm)	1.93 ± 0.78	1.94 ± 1.02	2.06 ± 1.19	0.01 ± 0.94	0.958	0.664
8 mm	MB (mm)	4.56 ± 1.49	3.53 ± 1.22	3.91 ± 1.65	NA	NA	0.277
	DB (mm)	4.23 ± 1.54	2.99 ± 1.44	3.21 ± 1.75	NA	NA	0.569
	P (mm)	2.05 ± 1.02	2.27 ± 1.14	1.95 ± 1.09	0.22 ± 0.71	0.073	0.224

Table 4. Comparison of mandibular measurements among the three groups. Data are presented as mean ± standard deviation. B-ABH, buccal alveolar bone height; L-ABH, lingual alveolar bone height; In-T, buccolingual inclination of tooth; In-B, buccolingual inclination of the alveolar bone; MB, mesiobuccal root; DB, distobuccal root; ML, mesiolingual root; DL, distolingual root. Results of P value of each measurement were divided into two columns. The first column (P1) presented the results of comparison between SB-T0 group and SB-T1 group, whereas the second column (P2) presented the results of comparison between SB-T1 group and Control group.

Measurement		SB-T0	SB-T1	Control group	T1-T0	P1	P2
B-ABH (mm)		1.08 ± 0.87	1.38 ± 1.25	1.31 ± 0.69	0.30 ±1.32	0.183	0.772
L-ABH (mm)		1.52 ± 0.69	2.07 ± 0.74	1.53 ± 0.50	0.55 ± 0.83	0.000	0.001
In-T (°)		-31.13 ± 10.52	-13.96 ± 9.19	-16.38 ± 6.57	17.17 ± 10.26	0.000	0.203
In-B (°)		-12.37 ± 5.71	-9.99 ± 5.68	-9.96 ± 3.96	2.38 ± 1.89	0.000	0.977
4 mm	MB (mm)	1.90 ± 0.83	2.74 ± 1.59	2.46 ± 1.18	0.84 ±1.52	0.002	0.389
	DB (mm)	3.08 ± 1.35	4.59 ± 2.54	4.02 ± 2.08	1.51 ± 2.19	0.000	0.300
	ML (mm)	3.03 ± 0.92	2.40 ± 0.75	2.75 ± 0.74	-0.62 ± 0.90	0.000	0.052
	DL (mm)	3.08 ± 0.95	2.68 ± 0.88	2.95 ± 1.11	-0.41 ± 0.78	0.004	0.242
6 mm	MB (mm)	3.10 ± 1.26	4.48 ± 1.75	4.21 ± 1.38	1.38 ±1.75	0.000	0.476
	DB (mm)	4.42 ± 1.67	6.21 ± 2.50	5.81 ± 2.13	1.79 ± 2.31	0.000	0.462
	ML (mm)	3.73 ± 1.24	2.98 ± 0.82	3.21 ± 0.97	-0.75 ± 1.01	0.000	0.268
	DL (mm)	3.53 ± 1.24	2.92 ± 1.01	3.13 ± 1.19	-0.61 ± 0.85	0.000	0.419
8 mm	MB (mm)	4.58 ± 1.62	6.54 ± 1.80	6.08 ± 1.59	1.96 ± 2.13	0.000	0.254
	DB (mm)	5.84 ± 1.76	7.81 ± 2.29	7.42 ± 2.03	1.97 ± 2.42	0.000	0.448
	ML (mm)	4.01 ± 1.40	3.22 ± 1.07	3.52 ± 1.19	-0.79 ± 0.95	0.000	0.264
	DL (mm)	3.78 ± 1.43	2.84 ± 1.30	3.37 ± 1.43	-0.94 ± 1.08	0.000	0.107

No competing interests reported.

Changes of vertical dimension and alveolar bone remodeling in patients with second molar scissors bite during orthodontic correction

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Abstract

Figures

Introduction

Methods

Results

Discussion

Conclusions

Declarations