|Year : 2016 | Volume
| Issue : 1 | Page : 18-27
Effectiveness of the damon system in the treatment of nonextraction orthodontic cases
Yasmine M Sayed1, Safaa M Gaballah2, Eman M El Shourbagy2
1 Orthodontic Department, Faculty of Dentistry, Cairo University, Cairo, ; Orthodontic Department, Faculty of Dentistry, Tanta University, Tanta, Egypt
2 Orthodontic Department, Faculty of Dentistry, Tanta University, Tanta, Egypt
|Date of Web Publication||26-Jul-2016|
Yasmine M Sayed
MDS, Orthodontic Department, Faculty of Dentistry, Tanta University, Tanta - 27941
Source of Support: None, Conflict of Interest: None
The purpose of this study was to evaluate the dental, skeletal, and soft-tissue change in crowding cases treated with nonextraction approach using the Damon system.
Materials and methods
The sample included 20 patients, with an average age of 17.8 ± 3.7 years, selected on the basis of pretreatment class I skeletal and molar relationships with an acceptable soft tissue facial profile, and a moderate crowding range between 4.0 and 9.0 mm for the maxilla and 2.0 and 6.0 mm for the mandible. None of them had received any orthodontic treatment before, or had extraction or any congenital anomalies such as supernumerary teeth.
The evaluation of the study was performed by detecting the dental, skeletal, and soft tissue changes between pretreatment and post-treatment study models and lateral cephalometric radiographs. The paired t-test was used for statistical analysis. The treatment required 20.7 ± 2.2 months to be finished, with an average of 13.8 ± 1.5 appointments.
The results of this study revealed that the correction of crowding was achieved through expansion of the dental arches and mandibular incisors proclination.
Keywords: damon system, expansion, nonextraction, self-ligating brackets
|How to cite this article:|
Sayed YM, Gaballah SM, El Shourbagy EM. Effectiveness of the damon system in the treatment of nonextraction orthodontic cases. Tanta Dent J 2016;13:18-27
|How to cite this URL:|
Sayed YM, Gaballah SM, El Shourbagy EM. Effectiveness of the damon system in the treatment of nonextraction orthodontic cases. Tanta Dent J [serial online] 2016 [cited 2018 Jul 16];13:18-27. Available from: http://www.tmj.eg.net/text.asp?2016/13/1/18/186942
| Introduction|| |
Self-ligating brackets are not new conceptually, having been pioneered in the 1930s. In the mid-1990s, Dwight Damon was intrigued by the idea of lateral posterior expansion using the Damon system. Damon developed a theory asserting that low friction and light forces distribute expansion forces gently and produce more biologically stable results. His philosophy was the impetus for the creation of his orthodontic appliance system . The use of self-ligating brackets has gained popularity recently in orthodontic treatment: in particular, the Damon appliance system. The Damon system uses passive self-ligation with the use of light forces of copper–nickel–titanium (CuNiTi) archwire to achieve arch development and to relieve dental crowding. Since then, both the brackets and the philosophy behind the system have undergone continuous evolution with the most recent bracket being the Damon Q. Dr Damon claimed that a significant amount of crowding could be relieved without extractions with faster treatment time, increased patient comfort, fewer visits, and excellent final results . Several investigations have studied the above-mentioned claims of the Damon system.
A constant agreement was found among studies that the Damon system produced a statistically significant expansion in all measurements in both arches, with most of the expansion occurring at the premolars ,,,,,,,. However, another study  found that a significant change was not seen in the canine area. Mikulencak  also showed that the maxillary arch expansion produced a 0.5° palatal uprighting of the maxillary molars during treatment. In contrast, Jackson  found that the amount of tipping did not show a significant association in either group. Many authors ,,,, reported that an alignment-induced increase in the proclination of the mandibular incisors was observed for both bracket groups. In a study by Ehsani  and Fleming et al. , Damon treatment resulted in a lingual root torque of upper incisors. In contrast, Vajaria et al.  found that the upper incisor position and angulation were not altered significantly, and Pandis et al.  found that self-ligating brackets seem to be equally efficient in delivering torque to maxillary incisors relative to conventional brackets in extraction and nonextraction cases. Al-Sanea  and Huang et al.  revealed an increase in anterior arch depth in both arches.
Aim of the work
The current clinical trial aimed to evaluate the changes that occur after treatment with the Damon system and to investigate whether or not the goals of the Damon system were met over the course of orthodontic treatment.
| Materials and Methods|| |
The sample of this study consisted of 20 patients seeking orthodontic treatment in the Orthodontic Department, Faculty of Dentistry, Tanta University. The patients' ages ranged from 13 to 23 years at the start of the treatment. Patients with good oral hygiene, permanent dentition, class I skeletal relationship with an acceptable soft tissue facial profile, class I molar relationship, and moderate maxillary and mandibular dental arch crowding were included in the study. Patients who had received any orthodontic treatment, extraction of any permanent teeth except third molar, skeletal discrepancy, and presence of supernumerary teeth or other congenital anomalies were excluded from selection. Written informed consent was obtained from each patient before orthodontic treatment. The following were recorded before treatment (T1) after thorough clinical examination with medical and dental history and after treatment (T2): extraoral and intraoral photographs; panoramic radiographic film; lateral cephalometric radiographs; and study models.
All patients were treated with a nonextraction approach using the Damon system appliance. Damon Q brackets (Ormco Corporation, Orange, California, USA) were bonded to the teeth from second premolar to second premolar; SnapLink passive self-ligating buccal tubes were bonded for first molars and titanium buccal tubes were bonded for second molars. The Damon Q brackets with optional torque values were not used as 'sets' otherwise the correct torque for each tooth was selected. Each tooth was polished, rinsed with water, dried, etched with 37% phosphoric acid for 30 s, and rinsed thoroughly with water for a minimum of 5 s per tooth with a forceful air/water spray. The enamel was dried with clean, oil-free compressed air to obtain a uniform, dull, frosty appearance. A very thin coat of sealant and bond enhancer (Ortho solo 740-0271; Ormco Corporation) was applied to the prepared tooth and air thinned. A small amount of light-cured two-way color change adhesive paste (Grengloo adhesive 740-0321; Ormco Corporation) was placed on the orthodontic bracket base. The bracket was placed on the tooth following the principles suggested by Andrews, in which the brackets were placed on the midpoint of the facial axis of the clinical crown, with the vertical bracket removable positioning gauge parallel to this axis. Thereafter, it was pressed gently and the excess adhesive around the bracket was removed with a clinical probe. Finalized position and light-curing using conventional LED light was started within 2 min and was left for 20 s for each bracket and 30 s for every molar tube.
All teeth were bonded and included in the archwire from the first appointment. Blocked-out teeth were managed by creating space with open Ni–Ti coil spring, and the displaced tooth was tied to the archwire with an elastic thread, a traction hook, or a 0.008” stainless steel ligature wire. The preloaded crimpable stops of the Damon CuNiTi archwire were placed on a section of the archwire where little movement of the archwire relative to the bracket was expected to occur. Thus, stops were placed as far as possible from crowded, displaced, or rotated teeth at either side of a bracket, or at either end of an interbracket span. Where crowding was bilateral, stops were placed anterior to the crowding typically at or near the midline ([Figure 1]).
|Figure 1: (a) Frontal view showing the archwire stops placed at either side of the maxillary central incisors a bracket and at either side of a mandibular left central incisor bracket. (b) Frontal view showing the change in the archwire stops position to be placed at either end of the maxillary central incisors interbracket span (midline) and between the mandibular right and left central incisor bracket (midline) after crowding relief.|
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The archwire was inserted into the slot so that it was not obstructing the slide. Ordinarily, archwire was inserted and the slides were closed easily with the fingertips. In cases with severely rotated teeth and archwire that was severely deflected and difficult to insert into the bracket slot, a ligature director was used to seat the archwire. Opening and closing of the bracket slide were carried out using SpinTek slide opening instrument or SpinTek slide opening/closing instrument (SpinTek slide opening/closing instrument 866-4016; Ormco Corporation) ([Figure 2]).
|Figure 2: (a) Insertion of the flat end of the SpinTek slide instrument into the slide and twisting 900 clockwise. (b) The flat end of the SpinTek slide instrument twisted 900 and slide opened. (c) Positioning the SpinTek slide instrument on both sides of the bracket and squeezing the opposing prong of the instrument upward.|
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Drop in hooks (Damon Q Drop-in Hooks 242-0114; Ormco Corporation) were added for any bracket in the vertical slots for intermaxillary elastic attachment while progressing through the Damon archwire sequence regardless of round or rectangular wires. The hook was inserted in the vertical slot and bended behind the tie wings, as shown in [Figure 3].
|Figure 3: (a) Inserting the drop in hook into the vertical slot. (b) Bending the drop in hook behind the tie wings.|
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Treatment phases and archwire sequencing were carried out according to the manufacturer's instructions and relative to each case pretreatment malocclusion. In the presented case, all teeth of the maxillary arch were bonded and included in the initial archwire in the first appointment; posterior composite buildup was placed on the occlusal surface of the mandibular first molars, followed by bonding of the mandibular teeth and insertion of the mandibular first archwire in the next appointment. In the first phase of treatment, a light Damon CuNiTi archwire measuring 0.013” and/or 0.014” in diameter was used to correct rotations, align the teeth, and initiate arch development. This phase lasted nearly 6 months, with appointments at 6-week intervals ([Figure 4]). In the first recall appointment, archwires were removed, permanent deformations were checked and replaced with new archwire if necessary, and original or new archwire was inserted. The next archwire used was 0.016” followed by 0.018” Damon CuNiTi archwires. Early light intermaxillary elastics of 3/16” and 2 oz (Quail 630-0011; Ormco Corporation) were used. Force was usually begun to be used in this phase with 0.018” Damon CuNiTi archwires according to each case canine relation and midline shift, if present.
|Figure 4: (a) Frontal, (b) right lateral, (c) left lateral, (d) maxillary occlusal, and (e) mandibular occlusal views showing the first 0.013" Damon CuNiTi archwire.|
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In the second phase, two archwires were often used, followed by CuNiTi archwires. This phase lasted from 3 to 6 months, with appointments at 6-week intervals. At this stage of treatment the following were carried out: full correction of all rotations and full alignment of all teeth were obtained; any space was consolidated and tooth contact was maintained; and torque control was initiated, by almost filling the 0.028” slot depth. The process of space consolidation between teeth was carried out on rectangular archwires using chain elastics from molar to molar. If all spaces between teeth were closed, the teeth were ligated together under the archwire with 0.008” stainless steel ligature wire. In patients who began this phase with fairly well-aligned teeth, a single 0.016 × 0.025” CuNiTi archwire was used for 3 months. The archwires used in the third phase were 0.016 × 0.025”, followed by 0.019 × 0.025” preposted stainless steel (Stainless steel archwire with preposted hooks distal to laterals; Ormco Corporation). This phase lasted nearly 3–6 months with appointments at 6-week intervals. In this phase of treatment, torque control was finished, and correct anteroposterior, buccolingual, and vertical relationships were obtained ([Figure 5]).
|Figure 5: (a) Frontal, (b) right lateral, (c) left lateral, (d) maxillary occlusal, and (e) mandibular occlusal views showing 0.016×0.025" preposted stainless steel archwire.|
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The archwires used in the final phase were 0.019 × 0.025” preposted stainless steel, followed by 0.019 × 0.025” Damon low-friction TMA (Ormco Corporation) or 0.019 × 0.025” Damon low-friction TMA only, depending on the final detailing needed. Final buccolingual, torque, and occlusal adjustments were carried out in this phase of treatment. This phase lasted nearly 3 months, with appointments at 6-week intervals. Debonding was performed using Damon Q debonding instrument (Damon Q debonding/repositioning instrument 866-4008; Ormco Corporation). Remaining adhesive was cleaned by cooling the adhesive with short blasts of cold air or water to revert it back to its original green color, and then removed with low-speed carbide burs, followed by sandpaper discs and a polishing cup or paste ([Figure 6]).
|Figure 6: Post-treatment (a) frontal, (b) right lateral, (c) left lateral, (d) maxillary occlusal and (e) mandibular occlusal views.|
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The lingual retainer was fabricated directly in the patient's mouth. A flattened braided lingual retainer wire (Bond-a-Braid #BAB2; Reliance Orthodontic Products Inc., Itasca, Illinois, USA) was bended, adjusted with pliers, and its adaptation was checked on the lingual surface of teeth, from canine to canine, and then bonded with a small amount of resin. Excess resin was eliminated from the wire with a high-speed diamond bur. Vacuum-formed retainers were fabricated on the final models and patients were instructed to wear them for 6 to 12 months while the soft and hard tissues remodel around the teeth. The following were recorded before (T1) and after treatment (T2) to determine the changes that occurred during treatment. On study casts, space analysis, arch width, arch depth, curve of Spee, overjet, overbite, and first molar angulation were measured. On lateral cephalometric radiographs, the following measurements were calculated for each lateral cephalogram. The cephalometric measurements were categorized into skeletal measurements (SNA, SNB, ANB, PtV-A, PtV-B, and y-axis), dental measurements (U1-SN°, U1-NA°, U1-NA mm, U1-A-Pog°, U1-A-Pog mm, U1-PtV mm, DU6-PTV mm, L1-MP°, L1-NB°, L1-NB mm, L1-A-Pog°, L1-A-Pog mm, L1-PtV mm, DL6-PTV mm, and interincisal angle), and soft tissue measurements (E Plane-Ls, E Plane-Li, superior sulcus depth, inferior sulcus depth, nasolabial angle, and mentolabial angle).
Study model and lateral cephalometric measurements were recorded and then the data were tabulated. To assess intraobserver reliability, the measurements were repeated for all patients after 2 weeks. Dahlberg's formula was used for reporting the error between measured and remeasured data . The coefficient of reliability was found to be on average 0.3 and 0.1° with corresponding P-values of 0.097 and 0.314 for lateral cephalometric and study model angular measurements, respectively. In addition, the mean error of the linear measurements was 0.2 mm (0.135) for the lateral cephalometric and 0.15 mm (0.247) for the study model. Data analysis was performed using SPSS version 21 (Chicago, USA). Statistical analysis of the data with different characteristics was performed with the use of the paired t-test. A two-tailed P-value of 0.05 was considered statistically significant with a 95% confidence interval, whereas P-values of 0.001 were considered highly significant with a 99.9% confidence interval.
| Results|| |
The current study was performed on 15 patients (12 female and three male) seeking orthodontic treatment in the Orthodontic Department, Faculty of Dentistry, Tanta University, after exclusion of five patients who decided to finish their treatment early before completion of follow-up. All study cases had class I skeletal and molar relationships with moderate arch length deficiency and an acceptable soft tissue facial profile. The patients were treated with a nonextraction approach using the Damon system appliance and mechanics ([Table 1]).
The study model analysis showed a nonsignificant change in the canine arch width in both maxilla and mandible. The maxillary inter first premolar width showed a significant increase, whereas mandibular inter first premolar width showed a nonsignificant increase. Maxillary and mandibular intersecond premolar width showed a significant increase. In addition, maxillary and mandibular intermolar width showed a significant increase ([Table 2]). A nonsignificant uprighting of the maxillary first molars and a significant uprighting of the mandibular first molar axis angle after expansion for the combined right and left first mandibular molars were found ([Table 3]).
|Table 2: Descriptive statistics of study model changes in arch width (mm)|
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|Table 3: Descriptive statistics of study model changes in molar angulations (deg.)|
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A significant increase in the maxillary canine and molar arch depths and a nonsignificant increase in the mandibular canine and molar arch depth were detected ([Table 4]). The maxillary and mandibular arch perimeters increased significantly. However, the curve of Spee decreased significantly. The overjet showed a significant decrease, and the overbite decreased nonsignificantly ([Table 5]).
|Table 4: Descriptive statistics of study model changes in arch depth (mm)|
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|Table 5: Descriptive statistics of study model changes in arch perimeter, curve of Spee, overjet, and overbite (mm)|
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The skeletal changes in lateral cephalometric radiographs after treatment with the Damon system were not significant ([Table 6]). The analysis of the dental linear measurements showed that the mandibular incisors advanced anteroposteriorly significantly in relation to NB and A-Pog lines. However, there was no significant difference in the anteroposterior position of the maxillary incisors after Damon treatment. The maxillary first molar distance to PtV decreased nonsignificantly; meanwhile, the mandibular first molar distance to PtV increased nonsignificantly ([Table 7]).
|Table 6: Descriptive statistics of skeletal measurements after treatment (mm)|
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|Table 7: Descriptive statistics of changes in dental linear measurements (mm)|
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The analysis of the dental angular measurements showed that the mandibular incisors proclined significantly; however, the maxillary incisors retroclined nonsignificantly. There was a nonsignificant decrease in the interincisal angle ([Table 8]). No significant differences were detected with regard to the soft tissue measurements ([Table 9]).
|Table 8: Descriptive statistics of changes in dental angular measurements (deg.)|
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|Table 9: Descriptive statistics of changes in soft tissue measurements after treatment|
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The patient presented at 16 years and 5 months with 9 mm maxillary arch crowding and 3 mm mandibular arch crowding. [Figure 7] shows the extraoral and intraoral photos before treatment. [Figure 8] shows the patient's facial and the dental appearance after the end of active treatment.
| Discussion|| |
The current study is a clinical trial that was performed by the same clinician, with strict inclusion criteria of the patients; this could improve the reliability of the outcome. The dropout rate in this study was five of 20 cases. In the present study, no attempt was made to compare treatment outcomes of the Damon system with conventional bracket system. However it was impossible to compare systems which are not allowing for similar treatment modality (i.e. arch widening) where arch expansion relies solely on archwires and bracket interactions. Moreover, with conventional brackets, space problems are usually handled differently compared with expansion alone, making them unsuitable as a control group. The sample was limited to class I, malocclusions treated with a nonextraction approach, so that expansion would not be compromised with movement of the teeth into the extraction spaces. Another consideration was amounts of initial crowding, which ranged from 4 to 9 mm, because the correction of a small amount of crowding will have little effect on dental arch form. The patients' ages ranged between 13 and 23 years. It was agreed, based on previous studies ,,, that the rate of dimensional changes in arch form rapidly declines after the eruption of permanent dentition. It is therefore reasonable to assume that arch form changes occurring in the present study were primarily appliance-related and the effect of growth was negligible.
The Damon self-ligating appliances possessed certain handling characteristics such as ease of ligation and consistent wire engagement without the undesirable force relaxation of elastomeric modules, thereby maintaining a constantly active status of engaged wires. This makes them suitable alternatives to conventional appliances. This is in agreement with the findings of Berger , Harradine , and Turnbull and Birnie . The mean treatment time in the current study was nearly similar to those reported in previous studies ,,. However, Jil-Agopian  reported a greater treatment time than that in the current findings. The average number of appointments required to finish the treatment in the present study is in accordance with that reported by Harradine , Jil-Agopian , and DiBiase et al.  However, Eberting et al.  reported a higher number of appointments. Total treatment time differs from one case to another, because not only the ligation technique but also many other factors such as patient cooperation variables and practitioner skills can influence the efficiency of treatment ,,,,. Many authors found a positive effect of the severity of crowding on treatment duration regardless of the bracket type used ,,,.
The study model analysis in the current study revealed overall transverse expansion, which was mostly evident at the level of the premolars, followed by the molars, with more expansion in the maxilla than in the mandible. Most of the transverse expansion was observed at the level of the premolars, which could highlight how the Damon appliance achieves its crowding relief. This finding is in accordance with that of Mikulencak , who found a clinically and statistically significant change in arch width dimension in the molar and premolar areas after treatment. A significant change was not seen in the canine area. Al-Sanea , Jackson , Ehsani , Vajaria et al. , and Fleming et al.  found a statistically significant expansion in all measurements in both arches, with most of the expansion occurring at the premolars. These were in partial agreement with the current study. In contrast, 2 mm expansion in the posterior segment of the arch yields a minimum increase in arch perimeter length, less than 1 mm , whereas an intercanine width increase provides more favorable space gain, albeit showing a higher probability of relapse compared with expansion in the molar region. Meanwhile, another study  reported that limiting mandibular canine expansion to 1 mm or less resulted in greater stability in the long run. The present study verified Damon's philosophy that the intercanine width is maintained with treatment, as arch length is gained with transverse expansion of the posterior teeth . This could support the stability concerns, as the available relapse data showed that premolar expansion and maintaining the intercanine width is advantageous for stability purposes, as expanded intercanine widths tend to decrease toward pretreatment values ,,,,.
The increases in transverse dimensions and the larger amount of expansion reported at the second premolar and first molar could be explained by the use of the Damon CuNiTi broad archwire shape, which are wider than conventional archwires, particularly in the buccal segments distal to the first premolar. This could make some doubts about the concept of physiologically determined tooth position and 'development of the arch' determined by the body and not by the clinician or the system applied alleged by Damon . Therefore, in the present study, the amount of expansion seemed to be correlated with the use of broad-shaped archwires and should not be assigned to the bracket type per se, which was supported by the findings of many studies ,,,,,. However, according to this logic, it would be expected that the amount of mandibular expansion would be similar to the maxillary after treatment, especially that the same archwires were used in both the maxilla and the mandible, but this was not observed, possibly because of the bone biology of the mandible. Sandström et al  suggested that buccal expansion in the mandibular arch is highly unpredictable and can be influenced by various factors, including anatomy of the underlying structures, inclination of the molars, and architecture of the oral musculature. The results of the study model analysis revealed that the molar expansion using the Damon system produced a small amount of molar palatal uprighting in the maxilla and a more significant degree of buccal uprighting in the mandible. This is in accordance with the previous results observed in a study by Mikulencak , which showed that the maxillary arch expansion using the Damon system produced a 0.5° palatal uprighting of the maxillary molars during treatment.
In relation to the nonextraction approach, control of labiolingual inclination of the incisors has been considered of paramount importance for a successful orthodontic treatment, as lack of control may result in undesirable flaring . The present study exhibited a nonsignificant change neither in the position nor in the angulation of the maxillary incisors, whereas the mandibular incisors advanced and proclined significantly as indicated by means of cephalometric analysis and supported by the increase in the canine and molar arch depth, which at the canines had the greatest change, indicating greater anteroposterior expansion on average in the anterior part of the arch. The increased arch depth in the current study is in accordance with that reported by Al-Sanea , who attributed this increase to the incisor advancement.
Even though the maxillary incisors were advanced nonsignificantly, they exhibited a nonsignificant retroclination – that is, the angles decreased and the distances increased. It was probably due to labial root torque rather than backward movement of the incisal tip because of the good torque control. In contrast, the mandibular incisors were advanced and proclined significantly. These findings were reflected on the significant decrease in the overjet. These findings were supported by Jung et al. , who found that the amount of upper lip closing force was related to the upper incisor angulation in class I malocclusions, and the upper lip force was greater than the lower lip force in class I and II malocclusions. This could explain why the upper incisors were not as proclined and advanced as the lowers. As all participants began treatment with class I skeletal and dental relationships, the class II elastics were used as a routine part of treatment in this study to correct canine relation and any class II tendencies in the dental arches and provide optimal interdigitation of posterior teeth. The force and duration of the class II elastics were considered minimal in this study; however, class II elastics are known to cause lower incisor proclination ,.
Another reason that could possibly contribute to lower incisor advancement was the correction of the deep curve of Spee, which was leveled and decreased significantly with continuous archwires that were not cinched back during the treatment. It is clear in the current study that the incisor advancement and transverse expansion had all been shown to significantly increase the maxillary and the mandibular arch perimeter, which in turn resulted in the alignment of teeth and alleviation of crowding. The amount of maxillary incisor advancement could be considered clinically acceptable. Although the mandibular incisors' value could be of clinical significance when maintaining lower incisor position during orthodontic therapy, it causes protrusion of the lower lip and an arguably unstable result. Little  demonstrated a tendency for mandibular incisors to upright in retention, causing lower incisor recrowding, but there is a possibility that proclined mandibular incisors retained with a fixed bonded appliance for long periods of time. The maxillary incisor findings were compatible with those of Vajaria et al. , who found that the upper incisor position and angulation were not altered significantly. However, other authors  reported different findings. They found a mean increase in maxillary incisor inclination of 1.12° for the Damon Q group, which was mainly because the measurements of that study were taken at the end of alignment and not after finishing the treatment. Hence, the performance of the stainless steel larger cross-section rectangular wires to obtain accepted inclination of the teeth was not reached. Mandibular incisor proclination and advancement are common findings in studies that analyze alleviation of crowding during treatment with the Damon system ,,,,. Limitation of the lower incisor advancement and proclination accompanied with self-ligating brackets could be carried out by performing interproximal reduction as a result of broad contacts and space gained , which was not carried out in this study. Moreover, individual patient variation needs to be considered when planning treatment. Therefore, the necessity of archwire bending to adjust the final torque may not be eliminated entirely . Alternatively, torquing auxiliaries and higher torque prescription brackets can be used to counteract the greater torque loss.
The results of the present study revealed that there was no effect on the sagittal position of the maxilla and the mandible. There was a nonsignificant increase in the SNA angle and PtV-A distance. These observations might suggest that A point was advanced a little anteriorly in competence with the labial root torque of the maxillary incisors. For the mandible, SNB angle did not change. However, there was a nonsignificant decrease in the PtV-B distance. The significant proclination of the mandibular incisors yielded posterior displacement of B point. A nonsignificant increase in the y-axis angle was detected, contributing to the decrease of the overbite. This overbite reduction could be due to the use of intermaxillary elastics, resulting in slight extrusion of the molars associated with the clockwise mandibular rotation. In this study, despite the minimal soft tissue changes after the treatments, it was found that nonextraction therapy with Damon appliances did not cause protrusive profiles and had no adverse effects on facial profiles. Patients had well-balanced and desirable facial esthetics with all profile measurements within normal limits.
| Conclusion|| |
On the basis of the results obtained after correction of arch crowding with Damon system appliances and mechanics, the conclusion of the current study can be summarized as follows: arch perimeter was gained by the increase in both arch width and arch depth. Only the mandibular incisors were advanced and proclined significantly, contradicting Damon's lip bumper theory.
- The overall transverse expansion was mostly evident at the level of the premolars, followed by the molars, with more expansion in the maxilla compared with the mandible, verifying Damon's philosophy that the intercanine width is maintained
- The expansion produced a small amount of uprighting in the maxillary molars and a more significant degree in the mandibular molars.
Damon appliance cannot rescue extraction cases. Straight soft tissue profile and upright incisor position are prerequisite for nonextraction treatment. Moreover, a harmonious chin and lip position is the key leading to the successful nonextraction treatment with Damon appliance.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9]