Abstract
Background
The objective was to compare the skeletal, dentoalveolar, and soft tissue effects of early Class II light elastics and PowerScope appliance used with self-ligating brackets in Class II Division 2 patients.
Methods
Thirty-one Class II Division 2 patients were divided into two groups. Group 1 (N = 16, mean age:15.06 ± 1.77 years) was treated with the Damon 3MX self-ligating system and early Class II light elastics. Group 2 (N = 15, mean age:15.87 ± 1.30 years) received Empower self-ligating brackets combined with PowerScope fixed functional appliance (FFA). Lateral cephalograms were taken before treatment (T0) and after achieving a Class I molar relationship (T1). Surveys assessing comfort and pain were analyzed at the beginning and after six months.
Results
Group 2 exhibited a significantly greater change in SNB° compared to Group 1, while increases in vertical skeletal measurements were greater in Group 1 (p < 0.05). Both groups exhibited maxillary and mandibular incisor protrusion with no significant difference. Lower molar extrusion (L6-H) was greater in Group 1 (2.77 ± 2.87 vs1.14 ± 1.77 mm, p = 0.038), whereas only Group 2 showed significant lower incisor intrusion (p = 0.002). Patients in the early elastic group generally reported better experiences with comfort-related situations. Pain levels at the 4th and 24th hours were significantly higher in Group 2 (p < 0.05).
Conclusion
Early light elastics and FFA were effective in normalizing Class II division 2 and corrected the molar relationship at the same time. Both treatment modalities demonstrated comparable dentoalveolar effects, except for the extrusion of lower molars and the intrusion of lower incisors. Patient comfort was better in the elastic group than in the FFA group.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12903-026-08643-6.
Keywords: Class II Division 2, Early Class II light elastic, Fixed functional appliance, PowerScope, Damon self-ligating
Introduction
Class II malocclusion is one of the most prevalent sagittal anomalies in orthodontics, impacting roughly one-third of the global population [1]. On the other hand, the prevalence of Class II Division 2 malocclusion is relatively low compared to other types malocclusions [2]. Due to specific morphological characteristics including retroclination of the maxillary incisors, deep bite, brachycephalic facial pattern, and inadequate facial profile structure, non-extraction treatment approaches are generally recommended for treatment of Class II Division 2 malocclusions [3].
With the proclination of the maxillary incisors, Class II Division 2 malocclusions are mostly transformed into Class II Division 1 malocclusions and are subsequently treated as Division 1 malocclusions [4]. Numerous orthodontic techniques have been introduced to treat Class II malocclusions, including intra- and inter-arch appliances, extraoral appliances, temporary anchorage devices, extraction patterns, and repositioning of the jaws with orthognathic surgery [5, 6]. Recently, there has been an increase in the trend toward treatment with intermaxillary elastics and fixed functional appliances [6].
The effects of Class II elastics include mesial movements of the mandibular molars, proclination of the mandibular incisors, distal movements and tipping of the maxillary incisors, extrusion of the mandibular molars and maxillary incisors, and clockwise rotation of the mandibular and occlusal planes [7–9]. However, intermaxillary elastics depend significantly on patient compliance for their effectiveness, and compliance in orthodontics can be inconsistent and challenging to manage predict [10].
In Class II cases with low growth potential, fixed functional appliances not requiring patient compliance are commonly preferred as another treatment option. Fixed functional appliances such as Herbst, Jasper Jumper, Eureka Spring, Forsus Fatigue Resistance Device etc. are recommended for patients who have completed the adolescent growth spurt and are in the later stages of puberty [11, 12]. Fixed functional appliances contribute to the correction of Class II malocclusion by stimulating mandibular growth, distal movement of the upper teeth, and mesial movement of the lower teeth [13]. The PowerScope is a relatively new hybrid fixed functional appliance introduced by American Orthodontics (Sheboygan, WI). The most recent modification of this appliance is the PowerScope 2 [14]. The appliance features a wire-to-wire installation, and the NiTi spring mechanism provides 260 g of force for continuous activation during treatment [15].
The Damon system is a fixed orthodontic technique that utilizes passive self-ligating brackets and Damon CuNiTi archwires. This system is designed to apply only light forces to move the teeth using low friction brackets [16, 17]. In recent years early Class II light elastics have been introduced, and are employed directly after placing the multibracket systems in combination with the initial round copper NiTi archwires [18]. There are case examples highlighting the use of early light Class II elastics with the Damon system [19–21], and limited studies [22, 23] evaluating the effects of early Class II elastic protocol.
There are limited studies in the literature comparing the effectiveness of fixed functional appliances and Class II elastics during the treatment of Class II malocclusion [5, 8, 24–26], and to the best of our knowledge, there is no study comparing the early Class II light elastic protocol with a fixed functional appliance in terms of treatment effectiveness. Therefore, the purpose of this study was to retrospectively compare the cephalometric skeletal, dentoalveolar, and soft tissue effects of the PowerScope 2 appliance combined with active self-ligating brackets versus the early Class II light elastics used with Damon bracket system. The secondary aim was to compare two different techniques regarding patient comfort and pain, assisting clinicians and patients in choosing the treatment method that is better accepted by them.
The null hypothesis of this study was that there was no difference in treatment effects between active self-ligating brackets combined with the PowerScope 2 and the Damon passive self-ligating bracket system combined with early Class II light elastics. Another null hypothesis was that there was no difference between these two methods regarding patient comfort and pain during treatment.
Materials and methods
This retrospective study analyzed the records available in the Department of Orthodontics. Ethical approval was obtained from the Non-Interventional Research Ethics Committee of the Faculty of Dentistry of Hacettepe University (SBA-24/192). Informed written consent was obtained from all participants to use their records for the purposes of the study.
The sample size calculation was conducted using G*Power software (G*Power v.3.0.10; Franz Faul, Universität Kiel Germany). Based on a previous study [27] and considering a mean difference of 1.5 mm in the overjet changes between the groups with a standard deviation of 1.1, the power analysis showed that with a significance level at 0.05 and 80% power, minimum 12 patients for each group were required for conducting this study. To further enhance the power of the test, all patients who met the selection criteria were included.
According to the following criteria, thirty-one patients who received one of the treatment protocols between February 2021 and December 2024 were retrospectively selected from the records of the Department of Orthodontics at the Faculty of Dentistry, Hacettepe University. The inclusion criteria for this retrospective study were as follows: (1) Patients presenting with at least a half-cusp Class II molar discrepancy at the beginning of treatment (2), Patients diagnosed with Class II Division 2 malocclusion in the permanent denttition (3), Patients who underwent non-extraction fixed orthodontic treatment using either the Damon passive self-ligating system combined with early Class II light intermaxillary elastics, or active self-ligating brackets combined with the PowerScope functional appliance (4), Patients who were between the ages of 12 and 18 at the beginning of treatment (5), Availability of lateral cephalograms and dental models at two key time points: at the beginning of treatment (T0) and after achieving a Class I molar relationship (T1) (6), Complon of a patient comfort/pain assessment form during treatment, with the form data available in the patient records (7), no dental agenesis, supernumerary teeth, impacted teeth, systemic diseases or syndromes. Exclusion criteria were as follows: (1) patients whose treatment plan changed due to the compliance (2), patients who had no complete orthodontic records available.
Diagnosis of Class II Division 2 malocclusion was based on a combination of clinical and cephalometric criteria, including retroclined maxillary incisors, deep overbite, and Class II molar relationship, rather than overjet alone.
An experienced orthodontist (H.T.B.) with over six years of experience provided treatment to all patients using a standardized approach procedure. For both groups, the treatment procedure entailed the use of fixed self-ligating orthodontic treatment, with a 0.022 prescription. The sample consisted of 31 patients divided into two groups:
Group 1 (Damon passive self-ligating bracket system combined with early Class II light elastic)
Group 1 included 16 patients (5 males and 11 females) with a mean age of 15.06 ± 1.77 years, treated with the 0.022 × 0.028” Damon 3MX passive self-ligating bracket system (Ormco/A Company, San Diego, USA) combined with early light Class II elastics. The wire sequence used in this group was as follows: Alignment and leveling were initiated with 0.014 and 0.018-inch Damon CuNiTi wires, used with full-time Quail 3/16” 2 oz shorty Class II elastics applied from L6 to U4. At the time of initial light wire, an anterior bite turbo was placed on the palatal surface of the upper central incisors to allow buccal segments to extrude. To prevent the retroclination of the upper incisors and the proclination of the lower incisors due to Class II elastics, high-torque brackets were used for the upper incisors and canines, while low-torque brackets were applied to the lower incisors and canines. After the initial alignment and leveling phase, 0.014 × 0.025 and 0.018 × 0.025-inch Damon CuNiTi archwires were used. Full-time Quail 3/16” 2 oz shorty Class II elastics and Parrot 5/16” Class II Reverse V (L6-U3-L4) elastics were applied at these stages. Additionally, elastic chains were placed under the wires if necessary to consolidate minor spaces. In the final stage, 0.019 × 0.025-inch upper and lower posted stainless steel archwires were utilized for major mechanics in both the upper and lower arches. At this stage, full-time Kangaroo 3/16” 4.5 oz Class II elastics from L6 to upper posts were applied until overcorrection was obtained. No palatal arches, quad-helices, palatal expanders, lip bumpers, or distalizing appliances were used. Patients were examined at 8-week intervals throughout the treatment. Elastics were discontinued when a Class I molar relationship was achieved. The Class II intermaxillary elastics were used for a mean period of 1.11 ± 0.49 years. Figure 1-A shows the intraoral photographs of a patient from Group 1 at pretreatment (T0) and 1-B shows after achieving Class I molar relationship (T1).
Fig. 1.
A: The intraoral photographs of a patients from group 1 at T0; B: The intraoral photographs of the same patient after achieving Class I molar relationship at T1
Group 2 (Empower self-ligating brackets combined with PowerScope 2 fixed functional appliance)
Group 2 included 15 patients (6 males and 9 females) with a mean age of 15.87 ± 1.30 years, treated with 0.022 × 0.028-inch Roth prescription active self-ligating brackets (Empower 2, American Orthodontics, Sheboygan, Wis) combined with PowerScope 2 (American Orthodontics, Sheboygan, Wis) fixed functional appliance (FFA). The archwire sequences for Group 2 were respectively 0.014-inch and 0.018-inch premium heat-activated Tanzo Cu-NiTi archwires, 0.014 × 0.025 and 0.018 × 0.025-inch premium heat-activated Tanzo Cu-NiTi archwires, and 0.019 × 0.025-inch stainless steel archwires. The patients were examined at 4-weeks interval. The PowerScope 2 appliance was installed when passive rectangular stainless steel archwires of 0.019 × 0.025-inch were applied to the maxillary and mandibular arches. A lingual crown torque was placed in the lower anterior segment to minimize the anticipated side effect of flaring caused by the FFA. Also, the mandibular archwire was consistently cinched distal to the molars. The maxillary attachment screw was placed mesial to the first molar on the maxillary rectangular stainless steel archwire and distal to the canine on the mandibular rectangular stainless steel archwire. The activations were done by the driver provided, and activations were performed as needed. This stage necessitated five to six months. No additional adjuncts, such as Class II elastics, were used during the follow-up periods. FFA was discontinued when a Class I molar and canine relationships were achieved. Figure 2 shows the intraoral photographs of a patient from Group 2 at pretreatment (T0) and after achieving.
Fig. 2.
A: The intraoral photographs of a patient from Group 2 at T0; B: The intraoral photographs of the same patient after achieving Class I molar relationship at T1
Class I molar relationship (T1). The total treatment time for Group 2 was 1.29 ± 0.26 years.
The active phase with Group 1 and 2 was undertaken until the Class II molar relation was corrected to Class I. The lateral cephalograms taken at T0 and T1 of all patients were obtained in centric occlusion with passive lip posture and were analyzed using Dolphin Imaging software (version 11.5; Dolphin Imaging and Management Solutions, Chatsworth, Calif.). Several angular and linear measurements were obtained from the lateral cephalograms to analyze the skeletal, dental, and soft tissue changes from T0 to T1 period (Table 1). The lateral cephalograms were traced blindly by a pre-calibrated examiner (E.A.) at two stages.
Table 1.
Definition of angular and linear measurements for lateral cephalometric
| Measurements | Definition of Measurements |
|---|---|
| SNA (°) | The angle between the SN plane and the NA plane. |
| SNB (°) | The angle between the SN plane and the NB plane. |
| ANB (°) | The angle between the NA plane and the NB plane. |
| GoGnSn (°) | The angle between the mandibular plane and the SN plane. |
| FMA (°) | The angle between the FH plane and the mandibular plane. |
| Occl plane-SN (°) | The angle formed between the SN plane and the occlusal plane. |
| Overjet (°) | The horizontal distance between the incisal ends of the upper and lower incisors |
| Overbite (°) | The vertical distance between the incisal ends of the upper and lower incisors. |
| U1- SN (°) | The angle of the upper incisor with the SN plane. |
| U1-NA (°) | The angle of the upper incisor with the NA plane. |
| U1-NA (mm) | The horizontal distance of the upper incisor to the NA plane. |
| L1-NB (°) | The angle of the lower incisor with the NB plane. |
| L1-NB (mm) | The horizontal distance of the lower incisor tip to the NB plane. |
| IMPA (°) | The angle of the lower incisor with the mandibular plane. |
| U6-V (mm) | The perpendicular distance between the mesiobuccal cusp of the upper first molar and the perpendicular drawn from point S to the FH plane. |
| L6-V (mm) | The perpendicular distance between the mesiobuccal cusp of the lower first molar and the perpendicular drawn from point S to the FH plane |
| U6-H (mm) | The perpendicular distance between the mesiobuccal cusp of the upper first molar and the ANS/PNS plane. |
| L6-H (mm) | The distance between the mesiobuccal cusp of the lower first molar and the perpendicular drawn from point Me to the vertical plane. |
| U1-V(mm) | The perpendicular distance between the upper central incisor tip and the perpendicular drawn from point S to the FH plane. |
| L1-V (mm) | The perpendicular distance between the lower central incisor tip and the perpendicular drawn from point S to the FH plane. |
| U1-H (mm) | The perpendicular distance between the upper central incisor and the ANS/PNS plane. |
| L1-H (mm) | The distance between the lower central incisor tip and the perpendicular drawn from the Me point to the vertical plane. |
| Nasolabial angle | The angle between the tip of the nose-subnasale-upper lip. |
| Upper lip-E plane (mm) | The distance between the most anterior point of the upper lip and the E plane (the plane formed between the soft tissue chin tip-soft tissue nasal tip). |
| Lower lip-E plane (mm) | The distance between the most anterior point of the lower lip and the E plane. |
| Facial convexity angle | The angle between the soft tissue glabella, subnasale and soft tissue pogonion. |
Data from the discomfort assessment forms based on the study of Bowman et al. [28], completed by patients during treatment, were also included in the study (supplementary file). A questionnaire was created and given to the patients to assess their comfort during the installation appointment of elastics and PowerScope 2 for Groups 1 and 2, respectively. In Group 1, patients answered the first eight questions at the end of the first month of intermaxillary elastic use and the remaining eight questions six months later. The patients in Group 2 answered the first eight questions one month after the fixed functional appliance was placed, and then they responded to the remaining eight questions six months later. In addition to the questionnaire, the patients were asked to record their pain intensity on a 10 mm visual analogue scale during the first month at 4 h, 24 h, 3 days, 1 week, and 1 month, using the terms “very comfortable” and “very uncomfortable” to describe their peripheral status. In Group 1, patients began recording pain intensity when the elastics were first applied, and in Group 2 when PowerScope 2 was initially used.
Statistical analysis
The data analysis was performed using IBM SPSS (Statistical Package for Social Sciences) version 26 software. To evaluate the study data, frequencies (number, percentage) were calculated for categorical variables, while descriptive statistics (mean, standard deviation, minimum, maximum, and median) were given for numerical variables.
Given that the sample sizes in the groups to be compared were less than 30, non-parametric statistical methods were applied without conducting normality tests.
The relationships between two independent categorical variables were assessed using the Chi-Square Test. In instances where the expected value assumption of the Chi-Square Test was not satisfied, Fisher’s Exact Test was employed for interpretation. The differences between two independent groups were examined using the Mann-Whitney U Test. The Wilcoxon Test was used to assess differences between two dependent numerical variables, while differences among more than two dependent numerical variables were evaluated using the Friedman Test. In cases where a significant difference was found using the Friedman Test, Bonferroni correction was applied to identify the source of the difference. Statistical significance was defined at the 0.05 level.
Results
Comparison of baseline data between the groups
The mean pretreatment age, gender distribution, cervical vertebral maturation index (CVMI) distribution, and treatment time are shown in Table 2. No significant differences were observed in baseline characteristics and treatment time between Groups 1 and 2 (Table 2).
Table 2.
Comparison of two groups in terms of age, gender and duration of treatment
| Group 1 (N = 16) | Group 2 (N = 15) | Z | p | |||
|---|---|---|---|---|---|---|
| Mean ± SD | Median (Min.-Max.) |
Mean ± SD | Median (Min.-Max.) |
|||
| Age (year) | 15.06 ± 1.77 | 16 (13–18) | 15.87 ± 1.30 | 16 (14–18) | -1.458 | 0.163 |
| Duration of treatment (year) | 1.11 ± 0.49 | 1.06 (0.49–2.06) | 1.29 ± 0.26 | 1.24 (0.81–1.76) | -1.542 | 0.129 |
| Skeletal Age | Number (%) | Number (%) | Chi-square | p | ||
| CVMI 3 | 3 (18.75%) | 0 (0%) | 3.139 | 0.371 | ||
| CVMI 4 | 5 (31.3%) | 6 (40%) | ||||
| CVMI 5 | 6 (37.5%) | 7 (46.7%) | ||||
| CVMI 6 | 2 (12.5%) | 2 (13.3%) | ||||
| Gender | Number (%) | Number (%) | Chi-square | p | ||
| Female | 11 (68.8%) | 9 (60%) | 0.259 | 0.611 | ||
| Male | 5 (31.3%) | 6 (40%) | ||||
Z: Mann-Whitney U Test
*p < 0.05 was significant
Min. Minimum, Max. Maximum, SD Standard Deviation, CVMI Cervical vertebral maturation index
At the beginning of the treatment (T0), there were no statistically significant differences between the two groups for most cephalometric variables, except for the overbite (mm), L1-NB°, and L1-V (mm) measurements (Table 3). Therefore, both groups were comparable regarding malocclusion severity. Only the L1-NB angle and L1-V distance were significantly higher in Group 2 compared to Group 1, which also led to a significantly lower overbite measurement in Group 2 at the T0 period (p < 0.05) (Table 3).
Table 3.
Comparison of initial cephalometric measurements (T0) between the groups
| Group 1 (N = 16) | Group 2 (N = 15) | Z | p | |||
|---|---|---|---|---|---|---|
| Mean ± SD | Median (Min.-Max.) |
Mean ± SD | Median (Min.-Max.) |
|||
| SNA° | 81.95 ± 2.33 | 81.65 (76.6–85.3) | 81.81 ± 2.28 | 82.3 (78.8–87.4) | -0.535 | 0.593 |
| SNB° | 76.61 ± 2.38 | 76.95 (72.7–80.6) | 77.09 ± 2.31 | 78 (73.3–80.6) | -0.712 | 0.476 |
| ANB° | 5.34 ± 1.7 | 5.65 (0.8–7.6) | 4.85 ± 1.37 | 4.5 (2.6-7) | -1.069 | 0.285 |
| GoGnSN° | 26.36 ± 4.86 | 27.6 (15.8–32.6) | 28.95 ± 4.97 | 30.2 (18.1–36.8) | -1.305 | 0.192 |
| FMA° | 18.43 ± 4.08 | 19.05 (10.7–24.7) | 19.62 ± 4.74 | 18.2 (11.7–29.8) | -0.158 | 0.874 |
| Occl P-SN° | 15.29 ± 4.77 | 14 (9.3–28.6) | 15.75 ± 5.72 | 16.2 (5.5–26.5) | -0.316 | 0.752 |
| Overjet (mm) | 4.28 ± 0.62 | 4.3 (3.4–5.6) | 4.07 ± 1.39 | 3.8 (2-6.9) | -0.852 | 0.394 |
| Overbite (mm) | 6.44 ± 1.47 | 6.95 (4.3–9.2) | 4.92 ± 1.3 | 5.2 (2.7–7.7) | -2.198 | 0.028* |
| U1-SN° | 87.76 ± 4.73 | 86.55 (80.5–97.3) | 87.75 ± 7.97 | 89.2 (68.9–96.2) | -0.692 | 0.489 |
| U1-NA° | 7.63 ± 3.57 | 7.45 (1.7–16.7) | 7.24 ± 8.24 | 7.9 (-10.8-22.8) | -0.138 | 0.890 |
| U1-NA (mm) | -1.58 ± 2.36 | -1.75 (-4.4-5.4) | -0.50 ± 2.51 | -0.7 (-5.9-5.9) | -1.880 | 0.060 |
| L1-NB (mm) | 1.98 ± 2.01 | 1.7 (-0.5-5.3) | 3.01 ± 1.66 | 2.3 (1.1–6.4) | -1.583 | 0.113 |
| L1-NB° | 19.37 ± 4.94 | 18.25 (12.8–29.6) | 22.47 ± 3.27 | 22.5 (17.8–27.4) | -2.135 | 0.033* |
| IMPA° | 93.48 ± 3.24 | 93.5 (87.2–99.6) | 94.33 ± 4.55 | 93.7 (84.9–102) | -0.396 | 0.692 |
| U6-H (mm) | 20.68 ± 2.61 | 20.25 (18-27.9) | 21.70 ± 2.20 | 21.3 (18.1–25.8) | -1.424 | 0.155 |
| U6-V (mm) | 40.78 ± 3.00 | 42.35 (33.5–43.9) | 42.43 ± 3.89 | 42.1 (33.5–50.7) | -1.127 | 0.260 |
| L6-H (mm) | 34.03 ± 3.72 | 33.6 (29.3–43.7) | 34.77 ± 2.90 | 34.9 (29.5–40.4) | -1.107 | 0.268 |
| L6-V (mm) | 39.49 ± 3.10 | 40 (33.5–43.3) | 41.99 ± 4.19 | 42 (33-50.6) | -1.760 | 0.078 |
| U1-H (mm) | 26.23 ± 2.65 | 26.15 (22.5–32.6) | 26.66 ± 2.41 | 26.4 (22.7–30.3) | -0.573 | 0.566 |
| U1-V (mm) | 67.17 ± 4.01 | 67.55 (60-73.2) | 69.26 ± 4.30 | 69.5 (63.2–77.5) | -0.969 | 0.333 |
| L1-H (mm) | 35.63 ± 2.06 | 35.7 (32.5–41) | 36.21 ± 3.11 | 36.3 (31.9–41.8) | -0.455 | 0.649 |
| L1-V (mm) | 62.24 ± 3.99 | 62.85 (57-69.1) | 65.72 ± 3.78 | 65.5 (59-74.1) | -2.077 | 0.038* |
| Nazolabial° | 111.52 ± 5.68 | 110.3 (102.1-122.8) | 106.92 ± 10.10 | 108.4 (87.4–122) | -1.246 | 0.213 |
| Upplip-E (mm) | 3.13 ± 1.52 | 2.8 (1.1–5.9) | 2.11 ± 1.61 | 2.3 (-0.9-4.5) | -1.405 | 0.160 |
| Lowlip-E (mm) | -2.97 ± 1.84 | -3.4 (-6.9–0.1) | -1.57 ± 2.64 | -2.8 (-4-3.5) | -1.543 | 0.123 |
| Facial convexity° | 3.10 ± 1.70 | 2.9 (-1.3-5.3) | 3.79 ± 2.17 | 3.1 (0.2-8) | -0.732 | 0.464 |
Z: Mann-Whitney U Test
*p < 0.05 was significant
Min. Minimum, Max. Maximum, SD Standard Deviation
Evaluation of differences in cephalometric measurements between and within groups
Table 4 presents skeletal, dental, and soft tissue cephalometric measurement changes between T0 and T1 and compares these changes between the groups.
Table 4.
Evaluation of differences in cephalometric measurements between and within groups
| Group 1 (N = 16) | Group 2 (N = 15) | Za | p | ||||
|---|---|---|---|---|---|---|---|
| Mean ± SD |
Median
(Min.-Max.) |
Mean ± SD |
Median
(Min.-Max.) |
||||
|
SNA° T1-T0 Zb;p |
-0.59 ± 0.95 | -0.35(-2.5-0.7) | 0.09 ± 1.83 | -0.1(-3.5-4.2) | -0.971 | 0.332 | |
| -2.190;0.029* | -0.142;0.887 | ||||||
|
SNB° T1-T0 Zb;p |
-0.08 ± 1.01 | -0.15(-1.5-1.6) | 0.82 ± 1.32 | 1.1(-2-2.8) | -2.236 | 0.025* | |
| -0.399;0.690 | -2.104;0.035* | ||||||
|
ANB° T1-T0 Zb;p |
-0.74 ± 0.97 | -0.85(-2.2-0.9) | -0.72 ± 0.94 | -0.6(-2.2-1.4) | -0.020 | 0.984 | |
| -2.509;0.012* | -2.588;0.010* | ||||||
|
GoGnSN° T1-T0 Zb;p |
2.84 ± 2.05 | 2.85(-0.4-7.1) | 0.19 ± 2.93 | -0.9(-3.4-5.7) | -2.709 | 0.007* | |
| -3.388;0.001* | -0.057;0.955 | ||||||
|
FMA° T1-T0 Zb;p |
3.11 ± 1.68 | 3.4(-0.1-5.5) | 0.63 ± 1.76 | 0.5(-2.6-3.2) | -3.283 | 0.001* | |
| -3.464;0.001* | -1.364;0.172 | ||||||
|
Occl P-SN° T1-T0 Zb;p |
3.11 ± 4.21 | 3.3(-10.3-9.7) | 4.41 ± 3.42 | 5.2(-2.4-12) | -0.613 | 0.540 | |
| -2.690;0.007* | -3.124;0.002* | ||||||
|
Overjet (mm) T1-T0 Zb;p |
-0.21 ± 1 | -0.35(-1.6-1.5) | -0.91 ± 1.91 | -0.7(-4.6-2) | -1.167 | 0.243 | |
| -0.802;0.422 | -1.791;0.073 | ||||||
|
Overbite(mm) T1-T0 Zb;p |
-4.49 ± 1.37 | -4.25(-6.9–2.1) | -3.69 ± 1.17 | -3.3(-6.9–1.8) | -1.761 | 0.078 | |
| -3.517;0.000* | -3.412;0.001* | ||||||
|
U1-SN° T1-T0 Zb;p |
10.41 ± 3.01 | 9.45(5.9–15.5) | 11.97 ± 6.71 | 12.7(1-26.1) | -0.870 | 0.384 | |
| -3.516;0.000* | -3.408;0.001* | ||||||
|
1-NA Zb;p |
10.24 ± 3.70 | 10.1(5-16.8) | 11.65 ± 8.27 | 12.1(-5.5-26.6) | -1.443 | 0.149 | |
| -3.517;0.000* | -3.125;0.002* | ||||||
|
1-NAmm Zb;p |
3.83 ± 2.33 | 3.5(0.4–8.2) | 2.73 ± 2.18 | 2.5(-1.4-6.3) | -1.127 | 0.260 | |
| -3.516;0.000* | -3.154;0.002* | ||||||
|
1-NBmm Zb;p |
2.96 ± 2.10 | 3.35(-0.6-6.9) | 2.61 ± 1.20 | 2.4(0.4–4.9) | -0.772 | 0.440 | |
| -3.259;0.001* | -3.411;0.001* | ||||||
|
1-NB Zb;p |
10.44 ± 4.98 | 10.25(2.6–20.1) | 9.02 ± 4.10 | 9.8(2.8–17.7) | -0.692 | 0.489 | |
| -3.517;0.000* | -3.410;0.001* | ||||||
|
IMPA Zb;p |
7.94 ± 4.05 | 7.5(0.5–16.7) | 7.87 ± 4.38 | 8.4(0.9–15.1) | -0.040 | 0.968 | |
| -3.516;0.000* | -3.408;0.001* | ||||||
|
U6-H Zb;p |
-0.46 ± 1.71 | -0.85(-2.8-2.6) | -0.97 ± 1.93 | -0.6(-4.6-1.7) | -0.396 | 0.692 | |
| -1.086;0.277 | -1.511;0.131 | ||||||
|
U6-V Zb;p |
-0.90 ± 2.23 | -1.65(-4-3.7) | -1.10 ± 2.37 | -1.3(-5.9-2.8) | -0.158 | 0.874 | |
| -1.552;0.121 | -1.535;0.125 | ||||||
|
L6-H Zb;p |
2.77 ± 2.87 | 2.7(-4.4-7) | 1.14 ± 1.77 | 1.2(-2.3-4) | -2.077 | 0.038* | |
| -2.794;0.005* | -1.961;0.049* | ||||||
|
L6-V Zb;p |
3.03 ± 3.46 | 2.05(-1.7-12.5) | 1.43 ± 2.66 | 1.3(-2.4-6.6) | -1.305 | 0.192 | |
| -3.000;0.003* | -1.818;0.069 | ||||||
|
U1-H Zb;p |
0.30 ± 1.88 | -0.15(-2.5-5.1) | -0.25 ± 1.37 | -0.4(-3.4-1.9) | -0.594 | 0.553 | |
| -0.427;0.669 | -0.597;0.551 | ||||||
|
U1-V(mm) T1-T0 Zb;p |
2.07 ± 2.34 | 2.35(-2.7-7.2) | 1.54 ± 2.70 | 1.9(-2.5-5.2) | -0.138 | 0.890 | |
| -2.844;0.004* | -1.933;0.053 | ||||||
|
L1-H (mm) T1-T0 Zb;p |
-0.54 ± 1.44 | -0.65(-2.6-3) | -2.53 ± 1.86 | -2.7(-6.7-1) | -3.086 | 0.002* | |
| -1.552;0.121 | -3.268;0.001* | ||||||
|
L1-V(mm) T1-T0 Zb;p |
3.37 ± 3.12 | 3.2(-3.6-8.3) | 2.78 ± 2.30 | 2.3(-1.6-6.3) | -0.455 | 0.649 | |
| -3.052;0.002* | -3.125;0.002* | ||||||
|
Nazolabial° T1-T0 Zb;p |
0.28 ± 6.96 | 0.45(-12-8.6) | 0.11 ± 6.39 | -1.5(-12.7-10.6) | -0.099 | 0.921 | |
| -0.414;0.679 | -0.085;0.932 | ||||||
|
Upplip-E (mm) T1-T0 Zb;p |
0.09 ± 1.35 | 0.25(-2.6-2.5) | 0.77 ± 1.27 | 0.6(-2.4-3) | -1.529 | 0.126 | |
| -1.765;0.078 | -2.424;0.015* | ||||||
|
Lowlip-E (mm) T1-T0 Zb;p |
1.65 ± 1.57 | 1.1(0.1–5.7) | 0.69 ± 1.57 | 0.9(-2.8-4) | -1.307 | 0.191 | |
| -3.519;0.000* | -1.645;0.100 | ||||||
|
Facial convexity° T1-T0 Zb;p |
1.45 ± 1.88 | 1.5(-2.4-5.2) | 3.10 ± 3.09 | 1.9(-1.1-10.8) | -1.345 | 0.178 | |
| -0.699;0.485 | -1.848;0.065 | ||||||
Min. Minimum, Max. Maximum, SD Standard Deviation
*p < 0.05 was significant
Za:Mann-Whitney U Test (Intergroup comparisons)
Zb:Wilcoxon Test (Intragroup comparisons)
A statistically significant decrease in the SNA angle in Group 1 was noted (p = 0.029). The Chanel in mandibular sagittal position related to the SNB angle from T0 to T1 was significantly greater in Group 2 compared to Group 1 (p = 0.025). The ANB angle showed a significant decrease in both groups (p < 0.05), and this change did not differ significantly between the groups. According to the vertical skeletal measurements, the FMA and GoGnSN angles significantly increased from T0 to T1 in Group 1 (p = 0.001). These increases were significantly greater in Group 1 than in Group 2 (p < 0.05). In both groups, the occlusal plane angle (Occl P-SN) showed a significant increase, while the overbite value demonstrated a notable decrease (p < 0.05) (Table 4).
The inclination of maxillary incisors according to U1-SN°, U1-NA°, and U1-NA (mm) measurements showed a significant increase in both Group 1 and 2 (p < 0.05), and no differences were found in these changes between the groups. Both treatment groups also produced significantly lower incisor proclination related to L1-NB (mm), L1-NB°, and IMPA° measurements (p < 0.05), and these changes did not differ between the groups (Table 4).
The movement of U6 in relation to vertical and horizontal planes did not exhibit significant changes in both Group 1 and Group 2. The L6-H distance significantly increased in both groups, demonstrating significant extrusion of the lower molars (p < 0.05). Moreover, the increase of L6-H measurement was significantly higher in Group 1 (2.77 ± 2.87 mm) compared to Group 2 (1.14 ± 1.77 mm) (p = 0.038). The forward movement of L6 relative to the vertical plane significantly increased only in Group 1 (3.03 ± 3.46 mm) (p = 0.003) (Table 4).
The movement of U1 in relation to the vertical plane showed a significant change only in Group 1, with an increase of 2.07 ± 2.34 mm (p = 0.004). The lower incisors significantly intruded only in Group 2, considering the L1-H measurement (-2.53 ± 1.86 mm), and this change was significantly greater in Group 2 than in Group 1 (-0.54 ± 1.44 mm) (p = 0.002). Lower incisors showed significant forward movement according to the vertical plane in both groups (p < 0.05). However, this change was not statistically significant when the groups were compared (Table 4).
According to the soft tissue measurements, the distance from the upper lip to the E-plane significantly increased in Group 2 (p = 0.015), and the distance from the lower lip to the E-plane significantly increased in Group 1 (p < 0.001) (Table 4).
Comparison of responses to discomfort questionnaire
Table 5 presents a comparison of responses to questions related to comfort. A statistically significant difference was observed between the groups for questions 4, 6/1, 6/5, 6/6, 7/1, 7/2, 7/4, 7/5, 8/1, 9/2, 9/3, 10/5, and 13 (p < 0.05).
Table 5.
Comparison of responses to discomfort questionnaire
| Question | Group | Median (Min.-Max.) |
A | B | C | D | E | Chi-Square | p |
|---|---|---|---|---|---|---|---|---|---|
| N(%) | N(%) | N(%) | N(%) | N(%) | |||||
| 1 | 1 | 1(1–2) | 14(87.5%) | 2(12.5%) | 0(0%) | 0(0%) | 0(0%) | 3.058FE | 0.113 |
| 2 | 1(1–2) | 9(60%) | 6(40%) | 0(0%) | 0(0%%) | 0(0%) | |||
| 2 | 1 | 4(1–5) | 1(6.3%) | 0(0%) | 4(25%) | 7(43.8%) | 4(25%) | 6.856FE | 0.123 |
| 2 | 3(1–4) | 2(13.3%) | 3(20%) | 4(26.7%) | 6(40%) | 0(0%) | |||
| 3 | 1 | 2(1–4) | 6(37.5%) | 9(56.3%) | 0(0%) | 1(6.3%) | 0(0%) | 5.543FE | 0.104 |
| 2 | 2(1–4) | 2(13.3%) | 7(46.7%) | 1(6.7%) | 5(33.3%) | 0(0%) | |||
| 4 | 1 | 1(1–2) | 13(81.3%) | 3(18.8%) | 0(0%) | 0(0%) | 0(0%) | 5.643FE | 0.038* |
| 2 | 2(1–4) | 6(40%) | 7(46.7%) | 0(0%) | 2(13.3%) | 0(0%) | |||
| 5 | 1 | 2(1–5) | 6(37.5%) | 8(50%) | 1(6.3%) | 0(0%) | 1(6.3%) | 3.867FE | 0.537 |
| 2 | 2(1–4) | 7(46.7%) | 6(40%) | 0(0%) | 2(13.3%) | 0(0%) | |||
| 6/1 | 1 | 4(2–4) | 0(0%) | 3(18.8%) | 1(6.3%) | 12(75%) | 0(0%) | 13.206FE | 0.001* |
| 2 | 3(2–5) | 0(0%) | 1(7.1%) | 7(50%) | 3(21.4%) | 3(21.4%) | |||
| 6/2 | 1 | 4(1–5) | 1(6.3%) | 2(12.5%) | 4(25%) | 6(37.5%) | 3(18.8%) | 5.393FE | 0.258 |
| 2 | 4(1–5) | 1(6.7%) | 1(6.7%) | 0(0%) | 7(46.7%) | 6(40%) | |||
| 6/3 | 1 | 3(1–4) | 1(6.3%) | 0(0%) | 14(87.5%) | 1(6.3%) | 0(0%) | 2.778FE | 1.000 |
| 2 | 3(2–3) | 0(0%) | 1(6.7%) | 14(93.3%) | 0(0%) | 0(0%) | |||
| 6/4 | 1 | 3(2–4) | 0(0%) | 3(18.8%) | 11(68.8%) | 2(12.5%) | 0(0%) | 5.366FE | 0.120 |
| 2 | 3(3–5) | 0(0%) | 0(0%) | 10(66.7%) | 2(13.3%) | 3(20%) | |||
| 6/5 | 1 | 2(1–4) | 5(31.3%) | 6(37.5%) | 1(6.3%) | 4(25%) | 0(0%) | 14.296 | 0.002* |
| 2 | 4(1–5) | 1(6.7%) | 0(0%) | 4(26.7%) | 6(40%) | 4(26.7%) | |||
| 6/6 | 1 | 3(1–3) | 3(18.8%) | 4(25%) | 9(56.3%) | 0(0%) | 0(0%) | 11.636 | 0.003* |
| 2 | 3(3–5) | 0(0%) | 0(0%) | 9(60%) | 4(26.7%) | 2(13.3%) | |||
| 7/1 | 1 | 2(1–3) | 4(25%) | 9(56.3%) | 3(18.8%) | - | - | 8.229FE | 0.017* |
| 2 | 3(1–3) | 3(20%) | 2(13.3%) | 10(66.7%) | - | - | |||
| 7/2 | 1 | 2(1–3) | 7(43.8%) | 8(50%) | 1(6.3%) | - | - | 10.761FE | 0.004* |
| 2 | 2(2–3) | 0(0%) | 9(60%) | 6(40%) | - | - | |||
| 7/3 | 1 | 2(1–3) | 7(43.8%) | 3(18.8%) | 6(37.5%) | - | - | 2.633FE | 0.323 |
| 2 | 2(1–3) | 3(20%) | 6(40%) | 6(40%) | - | - | |||
| 7/4 | 1 | 2(1–3) | 5(31.3%) | 10(62.5%) | 1(6.3%) | - | - | 12.309FE | 0.001* |
| 2 | 3(2–3) | 0(0%) | 6(40%) | 9(60%) | - | - | |||
| 7/5 | 1 | 1(1–3) | 11(68.8%) | 4(25%) | 1(6.3%) | - | - | 17.435FE | 0.000* |
| 2 | 2(2–3) | 0(0%) | 10(66.7%) | 5(33.3%) | - | - | |||
| 8/1 | 1 | 3(1–5) | 2(12.5%) | 4(25%) | 9(56.3%) | 0(0%) | 1(6.3%) | 17.392FE | 0.000* |
| 2 | 4(3–5) | 0(0%) | 0(0%) | 4(26.7%) | 9(60%) | 2(13.3%) | |||
| 8/2 | 1 | 3(3–4) | 0(0%) | 0(0%) | 12(75%) | 4(25%) | 0(0%) | 1.975FE | 0.513 |
| 2 | 3(2–4) | 0(0%) | 2(13.3%) | 10(66.7%) | 3(20%) | 0(0%) | |||
| 8/3 | 1 | 3(3–3) | 0(0%) | 0(0%) | 16(100%) | 0(0%) | 0(0%) | - | - |
| 2 | 3(3–3) | 0(0%) | 0(0%) | 15(100%) | 0(0%) | 0(0%) | |||
| 9/1 | 1 | 3(1–5) | 1(6.3%) | 4(25%) | 5(31.3%) | 4(25%) | 2(12.5%) | 6.802FE | 0.114 |
| 2 | 3(1–3) | 1(6.7%) | 5(33.3%) | 9(60%) | 0(0%) | 0(0%) | |||
| 9/2 | 1 | 3(1–5) | 6(37.5%) | 1(6.3%) | 5(31.3%) | 3(18.8%) | 1(6.3%) | 10.592FE | 0.019* |
| 2 | 3(2–4) | 0(0%) | 6(40%) | 6(40%) | 3(20%) | 0(0%) | |||
| 9/3 | 1 | 3(1–4) | 3(18.8%) | 1(6.3%) | 9(56.3%) | 3(18.8%) | 0(0%) | 6.485 | 0.044* |
| 2 | 3(2–3) | 0(0%) | 1(6.7%) | 14(93.3%) | 0(0%) | 0(0%) | |||
| 9/4 | 1 | 3(1–3) | 2(12.5%) | 3(18.8%) | 11(68.8%) | 0(0%) | 0(0%) | 3.980FE | 0.345 |
| 2 | 3(1–4) | 1(6.7%) | 1(6.7%) | 10(66.7%) | 3(20%) | 0(0%) | |||
| 9/5 | 1 | 2(1–4) | 6(37.5%) | 4(25%) | 3(18.8%) | 3(18.8%) | 0(0%) | 2.554FE | 0.592 |
| 2 | 1(1–4) | 9(60%) | 1(6.7%) | 3(20%) | 2(13.3%) | 0(0%) | |||
| 9/6 | 1 | 3(1–4) | 1(6.3%) | 2(12.5%) | 11(68.8%) | 2(12.5%) | 0(0%) | 3.236FE | 0.792 |
| 2 | 3(1–5) | 1(6.7%) | 1(6.7%) | 12(80%) | 0(0%) | 1(6.7%) | |||
| 10/1 | 1 | 1.5(1–3) | 8(50%) | 6(37.5%) | 2(12.5%) | - | - | 0.578FE | 0.878 |
| 2 | 1(1–3) | 9(60%) | 4(26.7%) | 2(13.3%) | - | - | |||
| 10/2 | 1 | 1(1–3) | 9(56.3%) | 5(31.3%) | 2(12.5%) | - | - | 0.580FE | 1.000 |
| 2 | 1(1–3) | 8(53.3%) | 6(40%) | 1(6.7%) | - | - | |||
| 10/3 | 1 | 2(1–3) | 6(37.5%) | 8(50%) | 2(12.5%) | - | - | 0.564FE | 0.894 |
| 2 | 2(1–3) | 6(40%) | 6(40%) | 3(20%) | - | - | |||
| 10/4 | 1 | 2(1–3) | 4(25%) | 7(43.8%) | 5(31.3%) | - | - | 0.236FE | 1.000 |
| 2 | 2(1–3) | 3(20%) | 7(46.7%) | 5(33.3%) | - | - | |||
| 10/5 | 1 | 1(1–2) | 10(62.5%) | 6(37.5%) | 0(0%) | - | - | 16.160FE | 0.000* |
| 2 | 3(1–3) | 1(6.7%) | 6(40%) | 8(53.3%) | - | - | |||
| 11/1 | 1 | 3(1–4) | 1(6.3%) | 3(18.8%) | 8(50%) | 4(25%) | 0(0%) | 2.067FE | 1.000 |
| 2 | 3(2–5) | 0(0%) | 3(20%) | 7(46.7%) | 4(26.7%) | 1(6.7%) | |||
| 11/2 | 1 | 3(1–4) | 1(6.3%) | 0(0%) | 13(81.3%) | 2(12.5%) | 0(0%) | 4.270FE | 0.350 |
| 2 | 3(3–3) | 0(0%) | 0(0%) | 15(100%) | 0(0%) | 0(0%) | |||
| 11/3 | 1 | 3(1–3) | 1(6.3%) | 1(6.3%) | 14(87.5%) | 0(0%) | 0(0%) | 1.875FE | 1.000 |
| 2 | 3(3–3) | 0(0%) | 0(0%) | 15(100%) | 0(0%) | 0(0%) | |||
| 12 | 1 | 2(1–3) | 5(31.3%) | 9(56.3%) | 2(12.5) | 0(0%) | 0(0%) | 5.304FE | 0.140 |
| 2 | 1(1–4) | 8(53.3%) | 3(20%) | 2(13.3%) | 2(13.3%) | 0(0%) | |||
| 13 | 1 | 2(1–2) | 4(25%) | 12(75%) | - | - | - | 3.895 | 0.048* |
| 2 | 1(1–2) | 9(60%) | 6(40%) | - | - | - | |||
| 14 | 1 | 4(1–4) | 3(18.8%) | 3(18.8%) | 0(0%) | 10(62.5%) | 6.085FE | 0.087 | |
| 2 | 3(1–4) | 1(6.7%) | 6(40%) | 3(20%) | 5(33.3%) | ||||
| 15 | 1 | 1(1–1) | 16(100%) | 0(0%) | - | - | - | - | - |
| 2 | 1(1–1) | 15(100%) | 0(0%) | - | - | - | |||
| 16 | 1 | 2(1–3) | 5(31.3%) | 8(50%) | 3(18.8%) | 0(0%) | 0(0%) | 7.131FE | 0.276 |
| 2 | 2(1–5) | 3(20%) | 7(46.7%) | 1(6.7%) | 1(6.7%) | 3(20%) | |||
|
Median (Min.-Max.) |
Mean ± SD | Z | p | ||||||
| 15/1 | 1 | 2(2–6) | 3.00 ± 1.41 | -0.495 | 0.621 | ||||
| 2 | 3(2–5) | 3.07 ± 1.03 |
FE: Fisher’s Exact Test, Z: Mann-Whitney U Test
Min. Minimum, Max. Maximum, SD Standard Deviation
*p<0.05 was significant
Based on the responses to the surveys conducted at the beginning of treatment, Group 1 selected “somewhat worsened” for the speech-related question (6/1) significantly more frequently than Group 2. Regarding the appearance-related question (6/5), Group 1 selected “improved” significantly more than Group 2, while the response “much worsened” was selected significantly less frequently by Group 1 than by Group 2. For the question regarding being teased (6/6), Group 1 selected “improved” significantly more often than Group 2, while the response “somewhat worsened” was significantly less frequent in Group 1 than in Group 2. Regarding tooth pain (7/1), Group 1 selected “a little” significantly more frequently than Group 2, while the response “a lot” was significantly less frequent in Group 1 than in Group 2. For jaw pain (7/2) and difficulty in opening the mouth wide/yawning (7/4), Group 1 selected “never” significantly more frequently than Group 2, while the response “a lot” was significantly less frequent in Group 1 than in Group 2. Regarding whether maintaining oral hygiene was burdensome (7/5), Group 1 selected “never” significantly more often than Group 2, while the response “a little” was significantly less frequent in Group 1 than in Group 2. When asked about the effect of treatment on academic performance (8/1), Group 1 selected “improved” significantly more frequently than Group 2, while the response “somewhat worsened” was significantly less frequent in Group 1 than in Group 2.
At the 6th month of treatment, when comparing responses from the survey, Group 1 selected “much improved” for the eating-related question (9/2) significantly more often than Group 2, while Group 1 selected “improved” significantly less frequently than Group 2. For the question regarding drinking (9/3), Group 1 selected “same” significantly less frequently than Group 2.
Regarding the difficulty of maintaining oral hygiene (10/5), Group 1 selected “never” significantly more frequently than Group 2, while the response “a lot” was significantly less frequent in Group 1 compared to Group 2.
Additionally, for the question on the need for extra orthodontic appointments due to appliance issues [13], Group 2 answered “yes” significantly more frequently than Group 1.
Evaluation of pain intensity between and within the groups
A statistically significant difference was found between Group 1 and Group 2 regarding VAS4H and VAS24H levels (Table 6). Pain intensity observed at the 4th and 24th hours were significantly greater in Group 2 than in Group 1 (p < 0.05).
Table 6.
Evaluation of pain intensity between and within the groups
| Group 1 (N = 16) | Group 2 (N = 15) | Z | p a | |||
|---|---|---|---|---|---|---|
| Mean ± SD | Median (Min.-Max.) |
Mean ± SD | Median (Min-Max.) |
|||
| VAS 4 H | 3.38 ± 2.80 | 3 (0–10) | 5.67 ± 2.64 | 6 (2–10) | -2.207 | 0.027* |
| VAS 24 H | 4.69 ± 2.33 | 5 (0–8) | 6.80 ± 2.68 | 7 (1–10) | -2.355 | 0.019* |
| VAS 3D | 3.44 ± 2.16 | 3 (0–7) | 4.47 ± 2.36 | 5 (1–7) | -1.301 | 0.193 |
| VAS 7D | 2.06 ± 2.08 | 2 (0–6) | 1.53 ± 1.73 | 1 (0–6) | -0.590 | 0.555 |
| VAS 1 M | 0.94 ± 1.24 | 0 (0–3) | 1.13 ± 1.46 | 0 (0–4) | -0.326 | 0.744 |
| Fr; pb | 33.714;<0.001* | 43.859;<0.001* | ||||
| Difference (Bonferroni) |
1M<4 H,24 H,3D 7D<24 H |
1M<4 H,24 H,3D 7D<4 H,24 H,3D |
||||
pa: Mann-Whitney U test, pb: Friedman Test
*p < 0.05 was significant
Min. Minimum, Max. Maximum, SD Standard Deviation
In both groups, the pain intensity experienced in the first month was significantly lower than in the other times (p < 0.001).
Discussion
This retrospective cephalometric study aimed to compare two protocols for treating Class II division 2 malocclusion, helping clinicians identify potential treatment options based on patient characteristics. In this study, we aimed to contribute to the existing literature by comparing the effects of the fixed functional appliance method with the treatment method using early light elastic force, along with the torque selection of brackets to minimize the side effects of Class II elastics. The ethical principles precluded the use of an untreated control group.
The treatment duration with fixed appliances typically ranges from 18 to 24 months. The longer the observation period, the more challenging it becomes to analyze small changes caused by active treatment [8]. For this reason, we compared the changes in treatment at the time when we achieved a Class I molar relationship in our study. In the present study, the mean time to achieve a Class I molar relationship in Group 1 (Damon with early Class II elastic) was 1.11 ± 0.49 years, while in Group 2 (PowerScope 2), it was 1.29 ± 0.26 years. In the early elastic group, by applying Class II elastics from the start of treatment, we were able to initiate sagittal correction during the aligning and leveling stages. Therefore, it was believed that this approach could shorten the time needed to achieve a Class I molar relationship. However, both treatment protocols achieved a Class I molar relationship in a similar time frame and did not differ significantly from each other.
In the study conducted by Nelson et al. [8], the skeletal effect for Class II correction was smaller in the elastic group than in the Herbst group [8]. In the present study, the SNB T1-T0 change was significantly greater in the FFA group than in the early elastic group. However, the increase in SNB for the FFA group was only 0.82 degrees, which cannot be considered clinically significant and may partly reflect residual growth rather than a true treatment effect. In a recent study conducted by Middha et al., the PowerScope appliance, compared to the untreated control group, did not show significant effects on skeletal mandibular growth. Instead, it primarily resulted in dentoalveolar changes that led to a considerable reduction in overbite [29]. Additionally, a study comparing the effects of fixed functional appliances and Class II intermaxillary elastics found that significant mandibular growth stimulation, compared to the untreated controls, did not occur with either treatment modality [25].
In our study, the GoGnSN, FMA, and L6-H T1-T0 measurements were significantly higher in the early elastic group compared to the FFA group. As reported in previous studies, this can be explained by the vertical component of the force applied to the lower molar teeth in the elastic group of our study [8, 30]. However, in contrast to our finding, some studies indicated that there was no significant difference between elastics and fixed functional appliances regarding vertical skeletal changes [5, 24, 25]. In our study, the significantly higher vertical skeletal parameters change in the early elastic group compared to the other group can be attributed to the use of elastics from the beginning of treatment, which resulted in significantly lower molar extrusion. Given the L1-H change, statistically greater lower incisor intrusion was noted in the FFA group compared to the early elastic group, a finding that agreed with previous studies that showed significant intrusion with fixed functional appliances [24, 29, 31, 32]. Based on the vertical movements, we believe that the correction of deep bite was mainly accomplished through the extrusion of the lower first molars in the early elastic group and the intrusion of the lower incisors in the FFA group in the present study. Patients with Class II Division 2 malocclusion typically show a hypodivergent growth pattern, marked by a prominent chin tip and decreased lower facial height [2, 33]. Considering the soft tissue characteristics of these patients, a treatment method using early Class II light elastics on initial aligning and leveling wires may be advantageous for increasing lower anterior facial height and reducing the prominence of the chin tip. However, considering the soft tissue profile changes evaluated in our study, no significant differences were observed between the elastic and FFA groups. In contrast to our findings, the study by Falcao et al. found that the Twinforce fixed functional appliance promoted a greater reduction in facial convexity than the Class II intermaxillary elastics [26]. The different results regarding facial convexity may be attributed to differences in the appliance and elastic protocol.
The Occl P-SN measurement significantly increased in both groups (clockwise rotation of occlusal plane), and this increase was similar between the two groups. This result was consistent with the clockwise rotation information previously reported for elastics and fixed functional appliances [15, 24, 34]. According to previous studies, retroclination is expected in the upper incisors after fixed functional appliance and Class II elastic treatments [9, 24, 25, 34, 35]. In the study conducted by Sayed et al. [36], early versus late use of Class II elastics was comparatively evaluated. Based on their findings, using light Class II elastics during the early phase did not cause excessive retroclination of the maxillary incisors and enabled a more controlled progression of the alignment process. Furthermore, the similar incisor inclinations observed in both the early and late elastic groups suggest that torque control is mainly achieved during the rectangular archwire stage. Consistent with these findings, in the present study, increases in U1-SN°, U1-NA°, and U1-NA (mm) values were statistically significant in both groups. The observed increase in maxillary incisor inclination may be attributed to the use of high-torque brackets in the early elastic group and the correction of maxillary incisor inclination prior to PowerScope 2 application in the FFA group.
Furthermore, in our study, unlike other studies [9, 24, 37], extrusion of the upper incisors was not observed in either treatment groups. We believe that this result was due to the force generated against extrusion by the contact of the lower incisors with the anterior bite turbos placed on the palatal surface of the upper central incisors in the early elastic group, while due to the significant proclination of the upper incisors in the FFA group which also led to relative intrusion. Both groups demonstrated a statistically significant increase in L1-NB (mm), L1-NB°, and IMPA° values, which are associated with lower incisor proclination. In other studies [8, 24, 38], comparable results were observed in both treatments involving fixed functional appliances and those utilizing Class II elastics. In contrast to our results, Cassidy et al. [6] reported that mandibular incisors were more proclined when fixed functional appliances were used than elastics. In the FFA group, we tried to alleviate this side effect as much as possible with thick stainless-steel wire selection, cinch back application, and placing lingual crown torque in the lower anterior segment. Some researchers have suggested that negative torque on mandibular incisor brackets would provide greater resistance to proclination of the lower incisors [39]. In the early elastic group, we aimed to minimize the proclination effect caused by the elastics by selecting low torque brackets for the lower incisors and canines.
According to a study by Skidmore et al. [40], patient cooperation is one of the most significant factors that prolong treatment duration. Additionally, it has been reported that good patient compliance reduces the treatment duration in Class II patients [41]. Therefore, in our study, a questionnaire was administered to assess how orthodontic treatments, including Class II elastics or FFA, affected patients’ comfort and pain levels during treatment. When comparing the comfort-related questions between the groups, the results indicated that the early Class II elastic group reported better experiences regarding “appearance”, “being teased”, “tooth pain”, “jaw pain and difficulty in opening the mouth wide/yawning”, “maintaining oral hygiene”, and “school academic performance” than FFA group. While previous studies suggested that the necessity of patient cooperation in Class II elastic treatment is a disadvantage [40, 42], our study presents an opposing perspective on this matter. Perhaps in the elastic group, the early initiation of correction through the use of light elastics from the beginning, along with the application of low-force and short-component elastics, provided ease of use for patients and minimized discomfort, making the treatment advantageous. Bowman et al. [28] investigated patients’ experiences with Forsus Fatigue Resistance Device (FFRD) and reported that most patients experienced discomfort (mostly cheek irritation) and functional limitations. However, in contrast to our findings, the majority of patients in their study who had previously worn rubber bands found FFRD to be easier. In the study by Arora et al. [43], PowerScope group experienced more discomfort during eating when compared with Forsus group. On the other hand, pain in the teeth and jaws, headaches, and sleep discomfort decreased over 30 days with both appliances. In our study, in the evaluations made after 6 months, the answers given to the questions showed that the discomfort felt was mostly in the direction of improvement. Additional orthodontic appointments due to appliance issues (the breakage of PowerScope) were more frequently needed in the PowerScope FFA group than the elastic group in the present study. Arora et al. [43] also reported more frequent patient appointments due to archwire breakage in the PowerScope group. Moreover, the pain assessment results in the present study indicated that while pain levels decreased over time in both groups, the initial pain levels were significantly higher in the FFA group. All these findings may influence the selection of the most suitable treatment option for patients.
According to our study’s findings, both treatments yielded successful outcomes in correcting deep bite and sagittal relationship in Class II division 2 malocclusion, with consistent results confirming the predominance of dentoalveolar changes for the two treatment protocols [9]. When deciding which of these protocols to use for treatment, other variables such as patient cooperation, cost-benefit analysis, and the preferences of both the professional and the patient should also be considered.
The primary limitations of this study include its retrospective design, the small patient population, and the fact that it focuses on a specific stage of treatment. Further studies that include a larger sample size and possibly an untreated control group are necessary. Due to a lack of scientific studies assessing the effects of early Class II elastics, additional studies on long-term outcomes are necessary to offer more comprehensive treatment recommendations. Additionally, these findings should be interpreted in light of the sample’s skeletal maturation status, as most patients had already passed their peak growth period, which may have limited the potential for skeletal changes and contributed to the predominance of dentoalveolar effects. While the present study aimed to evaluate the biomechanical effects of two different treatment systems under clinical conditions, future studies using standardized appliance systems and torque prescriptions may better clarify the isolated effects of treatment mechanics.
Conclusion
The null hypothesis, which stated that there would be no differences between the two treatment modalities, was partially rejected.
Both treatment modalities were effective in correcting deep bite and sagittal relationships in Class II Division 2 malocclusion, primarily through dentoalveolar changes.
Both treatment groups showed comparable changes in most dentoalveolar measurements, except for lower molar extrusion and lower incisor intrusion.
Patients in the early elastic group generally reported better experiences with comfort-related situations, including “appearance”, “tooth pain”, “jaw pain and difficulty in opening the mouth wide/yawning”, “maintaining oral hygiene”, and “school academic performance.”
Although pain decreased with time in both treatment modalities, the initial pain scores were significantly greater in the FFA group.
Supplementary Information
Abbreviations
- FFA
Fixed functional appliance
- CVMI
Cervical vertebral maturation index
- FFRD
Forsus Fatigue Resistance Device
Authors’ contributions
H.T.B. contributed to conceptualization, methodology, investigation, data curation, visualization, and writing.E.A. contributed to conceptualization, supervision, writing, review, and editing.
Funding
No funding was presented for this research.
Data availability
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Declarations
Ethics approval and consent to participate
The design protocol was approved by the Ethics Review Committee of Hacettepe University (number: GO SBA-24/192). Written informed consent was obtained from all participants included in the study. All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Proffit WR, Fields HW Jr, Moray LJ. Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey. Int J Adult Orthodon Orthognath Surg. 1998;13:97106. [PubMed] [Google Scholar]
- 2.Peck S, Peck L, Kataja M, Class II. Division 2 malocclusion: a heritable pattern of small teeth in well-developed jaws. Angle Orthod. 1998;68:9–20. [DOI] [PubMed] [Google Scholar]
- 3.Yousefian J, Trimble D, Folkman G. A new look at the treatment of Class II Division 2 malocclusions. Am J Orthod Dentofac Orthod. 2006;130:771–8. [DOI] [PubMed] [Google Scholar]
- 4.Bayram M. Combined orthodontic-orthopedic treatment of an adolescent Class II Division 2 patient with extreme deepbite using the Forsus Fatigue Resistant Device. Am J Orthod Dentofac Orthop. 2017;152:389–401. [DOI] [PubMed] [Google Scholar]
- 5.Jones G, Buschang PH, Kim KB, Oliver DR. Class II non-extraction patients treated with the Forsus Fatigue Resistant Device versus intermaxillary elastics. Angle Orthod. 2008;78:332–8. [DOI] [PubMed] [Google Scholar]
- 6.Cassidy SE, Jackson SR, Turpin DL, et al. Classification and treatment of Class II subdivision malocclusions. Am J Orthod Dentofac Orthop. 2014;145:443–51. [DOI] [PubMed] [Google Scholar]
- 7.Farret MM. Orthodontic biomechanics with intermaxillary elastics. Dent Press J Orthod. 2023;28:e23spe3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Nelson B, Hansen K, Hägg U. Class II correction in patients treated with Class II elastics and with fixed functional appliances: a comparative study. Am J Orthod Dentofac Orthop. 2000;118:142–9. [DOI] [PubMed] [Google Scholar]
- 9.Janson G, Sathler R, Fernandes TMF, et al. Correction of Class II malocclusion with Class II elastics: a systematic review. Am J Orthod Dentofac Orthop. 2012;143:383–92. [DOI] [PubMed] [Google Scholar]
- 10.Brandão M, Pinho HS, Urias D. Clinical and quantitative assessment of headgear compliance: a pilotstudy. Am J Orthod Dentofac Orthop. 2006;129:239–44. [DOI] [PubMed] [Google Scholar]
- 11.Singaraju GS, Vannala V, Ankisetti SA, et al. Evaluation of sagittal changes in Class II Div 2 patients with decelerating phase of growth by PowerScope appliance: a retrospective cephalometric investigation. J Pharm Bioallied Sci. 2019;11:8–15. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Paulose J, Antony PJ, Sureshkumar B, et al. PowerScope a Class II corrector–a case report. Contemp Clin Dent. 2016;7:221–5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Huang Y, Sun W, Xiong X, et al. Effects of fixed functional appliances with temporary anchorage devices on Class II malocclusion: a systematic review and meta-analysis. J World Fed Orthod. 2021;10:59–69. [DOI] [PubMed] [Google Scholar]
- 14.Al Hamdany AK, Hasan LA, Alrawi MNA, et al. PowerScope 2 functional appliance: a 3D finite element simulation of its action on the mandible. J Oral Biol Craniofac Res. 2023;13:299–305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Kalra A, Swami V, Bhosale V. Treatment effects of PowerScope fixed functional appliance–a clinical study. Folia Med (Plovdiv). 2021;63:253–63. [DOI] [PubMed] [Google Scholar]
- 16.Dh D. The Damon low-friction bracket; a biologically compatible straight-wire system. J Clin Orthod. 1998;32:670–80. [PubMed] [Google Scholar]
- 17.DiBiase AT, Nasr IH, Scott P, Cobourne MT. Duration of treatment and occlusal outcome using Damon3 self-ligated and conventional orthodontic bracket systems in extraction patients: a prospective randomized clinical trial. Am J Orthod Dentofac Orthop. 2011;139:e111–6. [DOI] [PubMed] [Google Scholar]
- 18.Birnie D. The Damon passive self-ligating appliance system. In: Graber LW, Vanarsdall RL, Vig KWL, editors. Orthodontics: Current Principles and Techniques. 5th ed. Elsevier; 2008. pp. 19–35.
- 19.Pavlović J, Simić S, Vujačić A, Vukićević V. Orthodontics treatment open byte with fixed Damon technique. Praxis Med. 2016;45:89–94. [Google Scholar]
- 20.Jnr MJC, Snr MJC. Unilateral Class II treatment using fixed orthodontic appliances with open coil spring, sliding hook and light Class II elastics. Cell. 1975;141:3106. [Google Scholar]
- 21.Cernei ER, Anistoroaei D, Golovcencu L, et al. The functional treatment of Angle Class II/2 malocclusion using Damon passive-self ligating system. Rom J Oral Rehabil. 2024;16:274–9. [Google Scholar]
- 22.Sayahpour B, Eslami S, Guderian R, et al. Outcome quality and treatment efficacy of early Class II elastics compared to late Class II elastics: a retrospective clinical investigation. Int J Orthod Rehabil. 2024;15:1–7. [Google Scholar]
- 23.Sayed MS, Sadek MM, Abbas NH. Class II malocclusion correction by two different intermaxillary elastics protocols: a randomized clinical trial. Egypt Orthod J. 2024;65:200–13. [Google Scholar]
- 24.Aras I, Pasaoglu A. Class II subdivision treatment with the Forsus Fatigue Resistant Device vs intermaxillary elastics. Angle Orthod. 2017;87:371–6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Jayachandran S, Wiltshire WA, Hayasaki SM, Pinheiro FH. Comparison of AdvanSync and intermaxillary elastics in the correction of Class II malocclusions: a retrospective clinical study. Am J Orthod Dentofac Orthop. 2016;150:979–88. [DOI] [PubMed] [Google Scholar]
- 26.Falcão ICMCF, Valarelli FP, Canuto LFG, et al. Soft tissue profile changes in Angle Class II patients treated with Twin Force or intermaxillary elastics—a comparison. J Orofac Orthop. 2021;82:71–81. [DOI] [PubMed] [Google Scholar]
- 27.Nelson B, Hägg U, Hansen K, Bendeus M. A long-term follow-up study of Class II malocclusion correction after treatment with Class II elastics or fixed functional appliances. Am J Orthod Dentofac Orthop. 2007;132:499–503. [DOI] [PubMed] [Google Scholar]
- 28.Bowman AC, Saltaji H, Flores-Mir C, et al. Patient experiences with the Forsus Fatigue Resistant Device. Angle Orthod. 2013;83:437–46. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29.Middha A, Shah YD, Gupta S, et al. A comparative analysis of treatment effects of PowerScope and AdvanSync2 in Class II Division 1 malocclusion: a retrospective study. Cureus. 2023;15:e49105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Proffit WR, Fields H, Sarver D. Contemporary Orthodontics. Volume 142. St. Louis: Mosby; 2000. [Google Scholar]
- 31.Miller RA, Tieu L, Flores-Mir C. Incisor inclination changes produced by two compliance-free Class II correction protocols for the treatment of mild to moderate Class II malocclusions. Angle Orthod. 2013;83:431–6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Cacciatore G, Ghislanzoni LTH, Alvetro L, et al. Treatment and posttreatment effects induced by the Forsus appliance: a controlled clinical study. Angle Orthod. 2014;84:1010–7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Lapatki B, Mager A, Schulte-Moenting J, Jonas I. The importance of the level of the lip line and resting lip pressure in Class II, Division 2 malocclusion. J Dent Res. 2002;81:323–8. [DOI] [PubMed] [Google Scholar]
- 34.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;114:430–6. [DOI] [PubMed] [Google Scholar]
- 35.Varghese RM, Subramanian AK, Sreenivasagan S. Comparison of dentoskeletal changes in skeletal Class II cases using two different fixed functional appliances: Forsus Fatigue Resistant Device and PowerScope Class II corrector—a clinical study. J Int Oral Health. 2021;13:234–44. [Google Scholar]
- 36.Sayed MS, Sadek MM, Abbas NH. Early versus late intermaxillary elastics in patients with Class II malocclusion: a randomized clinical trial. Angle Orthod. 2025;95(6):587–94. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37.Gao W, Li X, Bai Y. An assessment of late fixed functional treatment and the stability of Forsus appliance effects. Aust Orthod J. 2014;30:2–10. [PubMed] [Google Scholar]
- 38.Pangrazio-Kulbersh V, Berger JL, Chermak DS, et al. Treatment effects of the mandibular anterior repositioning appliance on patients with Class II malocclusion. Am J Orthod Dentofac Orthop. 2003;123:286–95. [DOI] [PubMed] [Google Scholar]
- 39.Vogt W. The Forsus Fatigue Resistant Device. J Clin Orthod. 2006;40:358–68. [PubMed] [Google Scholar]
- 40.Skidmore KJ, Brook KJ, Thomson WM, Harding WJ. Factors influencing treatment time in orthodontic patients. Am J Orthod Dentofac Orthop. 2006;129:230–8. [DOI] [PubMed] [Google Scholar]
- 41.Vig K, O’Brien K, Shnorhokian H, et al. Predictors for Class I and Class II treatment duration differ. J Dent Res. 1994;73:273. [Google Scholar]
- 42.Beckwith FR, Ackerman RJ Jr, Cobb CM, Tira DE. An evaluation of factors affecting duration of orthodontic treatment. Am J Orthod Dentofac Orthop. 1999;115:439–47. [DOI] [PubMed] [Google Scholar]
- 43.Arora V, Sharma R, Chowdhary S. Comparative evaluation of treatment effects between two fixed functional appliances for correction of Class II malocclusion: a single-center, randomized controlled trial. Angle Orthod. 2018;88:259–66. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.