# Comparison of Changes in Incisors Inclination and Dental Arch Dimensions in Damon and MBT Systems Using Dolphin Software

*
*
AUTHORS

Neda Eslami
^{
1
, 2
}
,
Farid Sharifi
^{
3
}
,
Athar Nasseri
^{
1
}
,
Arezoo Jahanbin
^{
1
, *
}

1 School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran

2 Dental Research Center, Mashhad University of Medical Science, Mashhad, Iran

3 Dentist, Mashhad, Iran

**How to Cite:**
Eslami
N, Sharifi
F, Nasseri
A , Jahanbin
A. Comparison of Changes in Incisors Inclination and Dental Arch Dimensions in Damon and MBT Systems Using Dolphin Software,
Iran J Ortho.
Online ahead of Print
; 15(1):e114444.
doi: 10.5812/ijo.114444.

ARTICLE INFORMATION

**Iranian Journal of Orthodontics:**15 (1); e114444

**Published Online:**May 11, 2021

**Article Type:**Research Article

**Received:**March 13, 2021

**Revised:**May 5, 2021

**Accepted:**May 5, 2021

**DOI**: 10.5812/ijo.114444

### Abstract

**Background:**
There is great controversy regarding the effect of MBT and Damon bracket systems on dental arch dimensions and incisor position.

**Objectives:**
We aimed to study the effects of two different brackets (MBT and Damon) on dental arch dimensions and incisors position after orthodontic treatment.

**Methods:**
In this retrospective study, the records of 20 patients who underwent orthodontic treatment with MBT or Damon bracket systems were studied. All patients had class I skeletal and dental malocclusion and were treated without extraction. The patients were treated either with Damon or MBT bracket systems (n = 10). Lateral cephalograms were traced using the Dolphin software to determine the position of incisors. In addition, transverse dimensions of dental arches were measured on occlusal photographs. Fishers’ exact test, independent-test, Man-Whitney, paired *t*-test, and Wilcoxon were used for statistical analysis. P < 0.05 was set as significant.

**Results:**
There was no significant difference between the two groups regarding age, sex, and initial values of the variables studied. U1-Apog (mm), upper inter-canine, lower inter-second premolar distance showed a significant difference before and after treatment in the Damon system. However, no significant difference was observed between initial and post-treatment values in the MBT group. L1-Apog (°), IMPA (°), maxillary inter-first and second premolars, inter-canine, and mandibular inter-canine distance was higher in the Damon system after treatment compared to MBT. Changes of the upper and lower transverse dimensions of the dental arches and the incisor positional did not reveal a notable difference in the Damon and MBT systems (P > 0.05).

**Conclusions:**
There was no significant difference regarding changes in dental arches and incisor positions between the Damon and MBT systems.

Keywords

### 1. Background

With the development of wire and metal technology, advisement of different bracket types has begun. The Damon and MBT systems are a small part of the vast world of brackets (1, 2).

Mclaughlin, Bennett and Trevisi (MBT) wished to improve treatment results by applying changes to the brackets. Their goal was to reduce the strain on molar attachments and prevent the increase of arch length during treatment (3).

The idea of self-ligating brackets was introduced in 1935. Over the last thirty years, with the invention of new devices, these brackets have been revived. The use of self-ligating brackets has increased in recent years. In 2002, about 8.7 percent of American orthodontists used at least one self-ligating system. This frequency increased to 42 percent in 2008 (4, 5). One of the most popular self-ligating systems used by orthodontists is the Damon system. Passive self-ligating brackets of Damon system were introduced in 1996 (6).

Studies have investigated the effect of both Damon and conventional bracket systems on the dimensions of the dental arch and the position of the incisors. Some studies showed that Damon system increased the arch length significantly compared to conventional bracket systems (7) while others believed that the total arch width is the same after orthodontic treatment irrespective of the type of the bracket system (8, 9).

Most studies revealed that the inclination of the incisors does not significantly differ after orthodontic treatment in most bracket systems (9-12).

### 2. Objectives

Considering the controversies regarding the effects of the Damon brackets compared to conventional bracket systems on the dimension of dental arches, the aim of the present study was to compare the position of the anterior incisors and the dimensions of the dental arches between the Damon and MBT bracket systems using Dolphin software.

### 3. Methods

In this retrospective study, pre-treatment and post-treatment lateral cephalograms and photographs of 20 patients who did not require extractions and were treated with the MBT or the Damon system were collected.

All patients had skeletal and dental class I malocclusion, complete permanent teeth, no previous orthodontic treatment, moderate crowding (4 - 6 mm) in both jaws and no cross bite. Patients were divided into two groups (n = 10).

In group 1, the 22-inch conventional MBT pre-adjusted bracket (Ormco Corporation orange, California, USA), and in group2, the 22-inch Damon brackets (self-ligating Damon 3Mx, Ormco, USA) were used.

The sequence of wires in the Damon system was 19 × 25 CuNiTi, 14 CuNiTi and 16 CuNiTi respectively. In the MBT system, the wire sequences were 14 HANT, 16 HANT, 19 × 25 HANT and 19 × 25 SS. No additional appliances such as headgear, or lip bumper were used. Lateral cephalometric images of patients were scanned and entered into the Dolphin software. Hard and soft tissue landmarks were traced by one investigator. The variables were measured by Dolphin software version 11.

The dimensions of the dental arches were measured by examining the photographs using the MacBook Ruler software. To calculate the magnification scale, the width of one upper central incisor was measured on the cast as well as the upper occlusal photograph. The scale was then applied to all calculations. The following landmarks were measured:

- Inter-canine width: The distance between the tip of the canine cusps on both sides.

- Width between the first premolars: The distance between the central fossa of the first two premolars on both sides.

- Width between the second premolars: The distance between the central fossa of the second premolars on both sides.

- Intermolar width: The distance between the mesial fossa of the first molars on both sides.

All measurements were obtained before and after the orthodontic treatment. Finally, the extracted data were entered into SPSS software version 20 for analysis.

The normality of the data was assessed by the Shapiro-Wilk test. Moreover, Fisher's exact test, independent *t*-test, Mann-Whitney, paired *t*-test and Wilcoxon were used to compare the two groups. P-value < 0.05 was considered significant.

### 4. Results

In this study, 20 patients including 16 women (80%) and 4 men (20%) aged between 14 to 33 years with the mean age of 19.5 ± 4.6 years participated. Fisher's exact test showed that the two groups were not significantly different in terms of sex distribution (P = 0.087). There was no significant distinction in the mean age between the groups (P = 0.052).

Solely, the mean of the IMPA (°) in the Damon was greater than the MBT group at the start of treatment (Table 1).

_{0}) Between the Two Groups

Variables/Groups | N | Mean ± SD | Min | Max | Median | Test Results |
---|---|---|---|---|---|---|

L1 -Apog (mm) | T = 1.17; P = 0.241 | |||||

Damon | 10 | 4.04 ± 2.19 | 0.90 | 7.20 | 3.55 | |

MBT | 10 | 3.05 ± 1.93 | 1.20 | 7.20 | 2.25 | |

U1-Apog (mm) | T = 0.76; P = 0.449 | |||||

Damon | 10 | 6.56 ± 1.58 | 3.70 | 9.40 | 6.45 | |

MBT | 10 | 6.45 ± 3.79 | 2.70 | 15.50 | 5.00 | |

U1-Apog (°) | T = 1.11; P = 0.283 | |||||

Damon | 10 | 29.20 ± 4.41 | 23.10 | 38.70 | 28.55 | |

MBT | 10 | 26.84 ± 5.11 | 20.00 | 37.30 | 25.80 | |

L1-Apog (°) | T = 1.65; P = 0.116 | |||||

Damon | 10 | 28.65 ± 3.78 | 24.40 | 34.50 | 27.30 | |

MBT | 10 | 25.67 ± 4.28 | 19.90 | 35.30 | 24.75 | |

U1_NA (mm) | Z = 1.36; P = 0.17 | |||||

Damon | 10 | 4.99 ± 2.63 | 0.50 | 9.10 | 4.90 | |

MBT | 10 | 3.91 ± 3.75 | -0.10 | 13.20 | 3.30 | |

U1_NA (°) | T = 0.946; P = 0.356 | |||||

Damon | 10 | 24.78 ± 5.59 | 13.10 | 31.30 | 25.20 | |

MBT | 10 | 21.97 ± 7.54 | 11.00 | 33.80 | 21.15 | |

IMPA (°) | T = 3.49; P = 0.003 | |||||

Damon | 10 | 98.60 ± 3.76 | 92.00 | 104.50 | 99.30 | |

MBT | 10 | 93.06 ± 3.32 | 86.20 | 97.60 | 93.15 | |

FMIA (°) | T = 0.489; P = 0.631 | |||||

Damon | 10 | 59.40 ± 2.97 | 55.00 | 64.80 | 60.15 | |

MBT | 10 | 58.49 ± 5.08 | 52.00 | 66.20 | 56.90 | |

Diff. inter maxillary molars distance | T = 1.42; P = 0.174 | |||||

Damon | 10 | 206.90 ± 31.41 | 146.00 | 249.00 | 214.00 | |

MBT | 10 | 190.30 ± 19.65 | 156.00 | 230.00 | 193.00 | |

Diff. inter maxillary second premolar distance | T = 1.10; P = 0.285 | |||||

Damon | 9 | 176.67 ± 31.00 | 122.00 | 219.00 | 170.00 | |

MBT | 10 | 164.10 ± 17.50 | 139.00 | 201.00 | 164.00 | |

Diff. inter maxillary first premolar distance | T = 1.26; P = 0.223 | |||||

Damon | 10 | 164.20 ± 27.07 | 103.00 | 198.00 | 171.50 | |

MBT | 10 | 151.20 ± 18.14 | 125.00 | 188.00 | 151.50 | |

Diff. inter maxillary canine distance | Z = 0.82; P = 0.413 | |||||

Damon | 9 | 155.89 ± 26.39 | 95.00 | 179.00 | 166.00 | |

MBT | 8 | 153.38 ± 15.68 | 138.00 | 184.00 | 149.50 | |

Diff. inter mandibular molar distance | T = 0.54; P = 0.600 | |||||

Damon | 10 | 150.60 ± 15.29 | 127.00 | 170.00 | 152.00 | |

MBT | 10 | 147.70 ± 7.54 | 138.00 | 160.00 | 145.50 | |

Diff. inter mandibular second premolar distance | T = 0.00; P = 1.00 | |||||

Damon | 10 | 128.20 ± 12.73 | 108.00 | 148.00 | 128.00 | |

MBT | 10 | 128.20 ± 11.01 | 108.00 | 145.00 | 128.50 | |

Diff. inter mandibular first premolar distance | T = 1.33; P = 0.199 | |||||

Damon | 10 | 121.40 ± 10.60 | 105.00 | 141.00 | 119.50 | |

MBT | 10 | 114.90 ± 11.21 | 96.00 | 129.00 | 114.50 | |

Diff. inter mandibular canine distance | T = 0.77; P = 0.451 | |||||

Damon | 10 | 99.00 ± 13.41 | 74.00 | 117.00 | 101.50 | |

MBT | 10 | 95.30 ± 7.12 | 84.00 | 105.00 | 94.50 |

The mean of the L-1Apog (°), IMPA (°), the distance between maxillary molars, the maxillary first premolars, the maxillary second premolars, the maxillary canines and the distance between the mandibular canines were significantly larger in the Damon group compared to the MBT (Table 2).

_{1}) Between the Two Groups

Variables/Groups | N | Mean ± SD | Min | Max | Median | Test Results |
---|---|---|---|---|---|---|

L1 -Apog (mm) | T = 1.48; P = 0.156 | |||||

Damon | 10 | 5.10 ± 1.72 | 2.20 | 8.10 | 4.95 | |

MBT | 10 | 3.91 ± 1.87 | 1.10 | 6.20 | 4.20 | |

U1-Apog (mm) | T = 0.72; P = 0.478 | |||||

Damon | 10 | 7.96 ± 1.70 | 6.00 | 11.10 | 7.95 | |

MBT | 10 | 7.40 ± 1.76 | 4.80 | 10.60 | 7.65 | |

U1-Apog (°) | T = 2.01; P = 0.059 | |||||

Damon | 10 | 33.24 ± 4.67 | 24.70 | 39.30 | 32.50 | |

MBT | 10 | 28.90 ± 4.98 | 21.90 | 39.10 | 27.90 | |

L1-Apog (°) | T = 2.68; P = 0.015 | |||||

Damon | 10 | 31.31 ± 3.91 | 24.90 | 35.50 | 31.60 | |

MBT | 10 | 26.11 ± 4.73 | 19.90 | 34.00 | 25.90 | |

U1_NA (mm) | T = 1.23; P = 0.235 | |||||

Damon | 10 | 6.67 ± 2.16 | 3.90 | 10.50 | 6.35 | |

MBT | 10 | 5.23 ± 3.01 | 1.00 | 9.90 | 5.70 | |

U1_NA (°) | T = 1.55; P = 0.137 | |||||

Damon | 10 | 29.49 ± 4.73 | 22.00 | 37.70 | 28.90 | |

MBT | 10 | 24.51 ± 8.95 | 12.30 | 36.50 | 27.35 | |

IMPA (°) | F = 6.49; P = 0.021 | |||||

Damon | 10 | 100.90 ± 6.64 | 85.40 | 111.30 | 100.85 | |

MBT | 10 | 93.19 ± 6.14 | 83.20 | 106.20 | 92.60 | |

FMIA (°) | Z = 1.13; P = 0.256 | |||||

Damon | 10 | 57.58 ± 8.36 | 51.10 | 78.80 | 54.15 | |

MBT | 10 | 59.10 ± 8.39 | 41.90 | 69.20 | 61.00 | |

Diff. inter maxillary molars distance | T = 2.15; P = 0.045 | |||||

Damon | 10 | 207.85 ± 16.99 | 179.00 | 230.00 | 208.75 | |

MBT | 10 | 192.50 ± 14.83 | 170.00 | 219.00 | 187.50 | |

Diff. inter maxillary second premolar distance | T = 2.17; P = 0.044 | |||||

Damon | 10 | 189.71 ± 13.99 | 166.10 | 211.00 | 193.00 | |

MBT | 10 | 175.00 ± 16.23 | 143.00 | 200.00 | 173.00 | |

Diff. inter maxillary first premolar distance | T = 2.26; P = 0.036 | |||||

Damon | 10 | 172.67 ± 10.44 | 159.70 | 188.00 | 172.50 | |

MBT | 10 | 159.20 ± 15.65 | 128.00 | 181.00 | 161.00 | |

Diff. inter maxillary canine distance | T = 3.02; P = 0.007 | |||||

Damon | 10 | 164.08 ± 9.59 | 148.80 | 177.00 | 166.50 | |

MBT | 10 | 149.70 ± 11.60 | 134.00 | 173.00 | 151.00 | |

Diff. inter mandibular molar distance | T = 1.09; P = 0.288 | |||||

Damon | 10 | 157.50 ± 12.45 | 137.00 | 177.00 | 158.00 | |

MBT | 10 | 151.20 ± 13.29 | 131.00 | 169.00 | 154.00 | |

Diff. inter mandibular second premolar distance | T = 1.03; P = 0.318 | |||||

Damon | 10 | 138.10 ± 11.08 | 124.00 | 156.00 | 136.50 | |

MBT | 10 | 132.40 ± 13.62 | 108.00 | 151.00 | 135.00 | |

Diff. inter mandibular first premolar distance | T = 1.52; P = 0.145 | |||||

Damon | 10 | 127.70 ± 9.68 | 115.00 | 144.00 | 126.50 | |

MBT | 10 | 120.30 ± 11.91 | 98.00 | 133.00 | 124.50 | |

Diff. inter mandibular canine distance | T = 2.57; P = 0.019 | |||||

Damon | 10 | 106.50 ± 7.34 | 93.00 | 117.00 | 106.50 | |

MBT | 10 | 97.60 ± 8.15 | 84.00 | 114.00 | 97.00 |

Comparison of changes in the measured variables did not reveal a significant difference before and after treatment amongst the two groups.

The mean of all variables except FMIA (**°**) increased in T_{1} relative to T_{0}, which was significant for the variables U1-Apog (mm), the distance between the maxillary canines and the second mandibular premolars (Table 3).

Variables/Groups | N | Mean ± SD | Min | Max | Median | Test Results |
---|---|---|---|---|---|---|

Diff. L1-Apog (mm) | ||||||

T_{0} | 10 | 4.04 ± 2.19 | 0.90 | 7.20 | 3.55 | T = 1.61; P = 0.141 |

T_{1} | 10 | 5.10 ± 1.72 | 2.20 | 8.10 | 4.95 | |

Diff. U1-Apog (mm) | T = 2.32; P = 0.046 | |||||

T_{0} | 10 | 6.56 ± 1.58 | 3.70 | 9.40 | 6.45 | |

T_{1} | 10 | 7.96 ± 1.70 | 6.00 | 11.10 | 7.95 | |

Diff. U1-Apog (°) | T = 2.18; P = 0.057 | |||||

T_{0} | 10 | 29.20 ± 4.41 | 23.10 | 38.70 | 28.55 | |

T_{1} | 10 | 33.24 ± 4.67 | 24.70 | 39.30 | 32.50 | |

Diff. L1-Apog (°) | T = 1.23; P = 0.249 | |||||

T_{0} | 10 | 28.65 ± 3.78 | 24.40 | 34.50 | 27.30 | |

T_{1} | 10 | 31.31 ± 3.91 | 24.90 | 35.50 | 31.60 | |

Diff. U1_NA (mm) | T = 1.79; P = 0.106 | |||||

T_{0} | 10 | 4.99 ± 2.63 | 0.50 | 9.10 | 4.90 | |

T_{1} | 10 | 6.67 ± 2.16 | 3.90 | 10.50 | 6.35 | |

Diff. U1_NA (°) | T = 1.85; P = 0.098 | |||||

T_{0} | 10 | 24.78 ± 5.59 | 13.10 | 31.30 | 25.20 | |

T_{1} | 10 | 29.49 ± 4.73 | 22.00 | 37.70 | 28.90 | |

Diff. IMPA (°) | T = 1.19; P = 0.263 | |||||

T_{0} | 10 | 98.60 ± 3.76 | 92.00 | 104.50 | 99.30 | |

T_{1} | 10 | 100.90 ± 6.64 | 85.40 | 111.30 | 100.85 | |

Diff. FMIA (°) | Z = 1.27; P = 0.203 | |||||

T_{0} | 10 | 59.40 ± 2.97 | 55.00 | 64.80 | 60.15 | |

T_{1} | 10 | 57.58 ± 8.36 | 51.10 | 78.80 | 54.15 | |

Diff. inter maxillary molar distance | T = 0.13; P = 0.901 | |||||

T_{0} | 10 | 206.90 ± 31.41 | 146.00 | 249.00 | 214.00 | |

T_{1} | 10 | 207.85 ± 16.99 | 179.00 | 230.00 | 208.75 | |

Diff. inter maxillary second premolar distance | T = 1.87; P = 0.098 | |||||

T_{0} | 9 | 176.67 ± 31.00 | 122.00 | 219.00 | 170.00 | |

T_{1} | 10 | 189.71 ± 13.99 | 166.10 | 211.00 | 193.00 | |

Diff. inter maxillary first premolar distance | T = 1.29; P = 0.231 | |||||

T_{0} | 10 | 164.20 ± 27.07 | 103.00 | 198.00 | 171.50 | |

T_{1} | 10 | 172.67 ± 10.44 | 159.70 | 188.00 | 172.50 | |

Diff. inter maxillary canine distance | Z = 2.67; P = 0.008 | |||||

T_{0} | 9 | 155.89 ± 26.39 | 95.00 | 179.00 | 166.00 | |

T_{1} | 10 | 164.08 ± 9.59 | 148.80 | 177.00 | 166.50 | |

Diff. inter mandibular molar distance | T = 1.59; P = 0.146 | |||||

T_{0} | 10 | 150.60 ± 15.29 | 127.00 | 170.00 | 152.00 | |

T_{1} | 10 | 157.50 ± 12.45 | 137.00 | 177.00 | 158.00 | |

Diff. inter mandibular second premolar distance | T = 2.39; P = 0.041 | |||||

T_{0} | 10 | 128.20 ± 12.73 | 108.00 | 148.00 | 128.00 | |

T_{1} | 10 | 138.10 ± 11.08 | 124.00 | 156.00 | 136.50 | |

Diff. inter mandibular first premolar distance | T = 1.68; P = 0.127 | |||||

T_{0} | 10 | 121.40 ± 10.60 | 105.00 | 141.00 | 119.50 | |

T_{1} | 10 | 127.70 ± 9.68 | 115.00 | 144.00 | 126.50 | |

Diff. inter mandibular canine distance | T = 1.51; P = 0.165 | |||||

T_{0} | 10 | 99.00 ± 13.41 | 74.00 | 117.00 | 101.50 | |

T_{1} | 10 | 106.50 ± 7.34 | 93.00 | 117.00 | 106.50 |

In none of the variables were the two groups significantly different. Paired *t*-test and Wilcoxon test were used to compare the two groups (Table 4).

Variables/Groups | N | Mean ± SD | Min | Max | Median | Test Results |
---|---|---|---|---|---|---|

Diff. L1-Apog (mm) | Z = 1.73; P = 0.083 | |||||

T_{0} | 10 | 3.05 ± 1.93 | 1.20 | 7.20 | 2.25 | |

T_{1} | 10 | 3.91 ± 1.87 | 1.10 | 6.20 | 4.20 | |

Diff. U1-Apog (mm) | Z = 1.79; P = 0.074 | |||||

T_{0} | 10 | 6.45 ± 3.79 | 2.70 | 15.50 | 5.00 | |

T_{1} | 10 | 7.40 ± 1.76 | 4.80 | 10.60 | 7.65 | |

Diff. U1-Apog (°) | T = 1.20; P = 0.261 | |||||

T_{0} | 10 | 26.84 ± 5.11 | 20.00 | 37.30 | 25.80 | |

T_{1} | 10 | 28.90 ± 4.98 | 21.90 | 39.10 | 27.90 | |

Diff. L1-Apog (°) | T = 0.35; P = 0.734 | |||||

T_{0} | 10 | 25.67 ± 4.28 | 19.90 | 35.30 | 24.75 | |

T_{1} | 10 | 26.11 ± 4.73 | 19.90 | 34.00 | 25.90 | |

Diff. U1_NA (mm) | Z = 1.43; P = 0.153 | |||||

T_{0} | 10 | 3.91 ± 3.75 | -0.10 | 13.20 | 3.30 | |

T_{1} | 10 | 5.23 ± 3.01 | 1.00 | 9.90 | 5.70 | |

Diff. U1_NA (°) | T = 1.34; P = 0.213 | |||||

T_{0} | 10 | 21.97 ± 7.54 | 11.00 | 33.80 | 21.15 | |

T_{1} | 10 | 24.51 ± 8.95 | 12.30 | 36.50 | 27.35 | |

Diff. IMPA (°) | T = 0.09; P = 0.932 | |||||

T_{0} | 10 | 93.06 ± 3.32 | 86.20 | 97.60 | 93.15 | |

T_{1} | 10 | 93.19 ± 6.14 | 83.20 | 106.20 | 92.60 | |

Diff. FMIA (°) | T = 0.35; P = 0.732 | |||||

T_{0} | 10 | 58.49 ± 5.08 | 52.00 | 66.20 | 56.90 | |

T_{1} | 10 | 59.10 ± 8.39 | 41.90 | 69.20 | 61.00 | |

Diff. inter maxillary molar distance | T = 0.42; P = 0.685 | |||||

T_{0} | 10 | 190.30 ± 19.65 | 156.00 | 230.00 | 193.00 | |

T_{1} | 10 | 192.50 ± 14.83 | 170.00 | 219.00 | 187.50 | |

Diff. inter maxillary second premolar distance | T = 2.16; P = 0.059 | |||||

T_{0} | 10 | 164.10 ± 17.50 | 139.00 | 201.00 | 164.00 | |

T_{1} | 10 | 175.00 ± 16.23 | 143.00 | 200.00 | 173.00 | |

Diff. inter maxillary first premolar distance | T = 1.66; P = 0.131 | |||||

T_{0} | 10 | 151.20 ± 18.14 | 125.00 | 188.00 | 151.50 | |

T_{1} | 10 | 159.20 ± 15.65 | 128.00 | 181.00 | 161.00 | |

Diff. inter maxillary canine distance | T = 0.73; P = 0.491 | |||||

T_{0} | 8 | 153.38 ± 15.68 | 138.00 | 184.00 | 149.50 | |

T_{1} | 10 | 149.70 ± 11.60 | 134.00 | 173.00 | 151.00 | |

Diff. inter mandibular molar distance | T = 1.09; P = 0.302 | |||||

T_{0} | 10 | 147.70 ± 7.54 | 138.00 | 160.00 | 145.50 | |

T_{1} | 10 | 151.20 ± 13.29 | 131.00 | 169.00 | 154.00 | |

Diff. inter mandibular second premolar distance | T = 1.35; P = 0.209 | |||||

T_{0} | 10 | 128.20 ± 11.01 | 108.00 | 145.00 | 128.50 | |

T_{1} | 10 | 132.40 ± 13.62 | 108.00 | 151.00 | 135.00 | |

Diff. inter mandibular first premolar distance | T = 1.75; P = 0.115 | |||||

T_{0} | 10 | 114.90 ± 11.21 | 96.00 | 129.00 | 114.50 | |

T_{1} | 10 | 120.30 ± 11.91 | 98.00 | 133.00 | 124.50 | |

Diff. inter mandibular canine distance | T = 0.75; P = 0.472 | |||||

T_{0} | 10 | 95.30 ± 7.12 | 84.00 | 105.00 | 94.50 | |

T_{1} | 10 | 97.60 ± 8.15 | 84.00 | 114.00 | 97.00 |

### 5. Discussion

The aim of the present study was to compare changes in the incisors position and dimensions of the dental arches in MBT and Damon orthodontic systems using the Dolphin software. Comparison of mean values of variables at the beginning of the treatment showed no statistically significant difference except for the IMPA (°) between the MBT and Damon system.

Comparison of pre-treatment and post-treatment data exhibited that the mean values of U1-Apog (mm), the distance between the maxillary canines and the distance between the second mandibular premolars were statistically significant different in the Damon system. However, there were no statistically significant differences in the mean values of incisors position and dental arch dimensions in the MBT system before and after the treatment. On the other hand, the results obtained after the treatment in the two groups showed that the mean L1-Apog (°), IMPA (°), the distance between the first maxillary premolars, the distance between the second maxillary premolars, the distance between the maxillary canines and the distance between the mandibular canines in the Damon group were statistically significantly larger than the MBT group. According to this study, changes in transverse dimensions of the maxillary and mandibular arches as well as the position of the upper and lower incisors after treatment were similar in both Damon and MBT systems.

According to Damon's philosophy, light biological forces do not exert additional force on the muscles. Instead, the dental arch is aligned by transverse expansion at the posterior arch. According to this theory, the muscles around the mouth, such as the orbicularis oris and mentalis, also act as a lip-bumper and minimize the anterior movement of the incisors. Damon also claims that the inter mandibular canines width does not change significantly in this system (9, 11). However, since the use of the Damon system imposes a higher cost on the patient than the MBT system, and the use of the MBT system is more common among orthodontists; it is important to prove the above-mentioned claims. The present study did not find a significant difference in incisor inclination or dimensional changes of the arch between the MBT and Damon groups; therefore, it can be said that the two systems do not differ remarkably regarding their efficiency.

In a study by Pandis et al., conventional orthodontic therapy was compared to the Damon's system using lateral cephalography. The data showed that L1-Apog (°) did not differ statistically significantly between the two groups (32.11 in the conventional group versus 31.07 in the Damon group) after treatment. The amount of this change was higher in the Damon than the conventional group (about 9 degrees vs. 7 degrees), although this difference was not statistically significant. In our study, there was a significant difference in L1-Apog (°) in the conventional and Damon groups (31.31 vs. 26.11 degrees) before and after the treatment. However, similar to the previous study, this change was not significant between the two groups (10).

In addition, Pandis et al. also examined the width of the dental arches. In their study, the inter canine width was not significantly different between the two groups after treatment, but the intermolar width was significantly different (10). In the present study, the distance between the first maxillary premolars, the distance between the second maxillary premolars, the distance between the maxillary canines and the inter mandibular canine distance were statistically significantly different between the two groups after treatment. In line with the findings of the Pandis study, MBT and Damon systems were similar in terms of changes in dental arches and the position of incisors.

In 2009, Tecco et al. compared transverse changes of the maxillary arch during orthodontic treatment in MBT (3m Unitek) and Damon 3mx (Ormco) systems. The results of their study showed that in both groups, after 12 months of treatment, all transverse dimensions of the arch in the intermolar to inter-canine area increased significantly, but there was no notable difference between the two systems (13). The amount of crowding was mild in their study, while our patients had moderate crowding.

In another similar study conducted by Lombardo et al., three types of brackets were compared in terms of their impact on the anterior teeth, including the Damon bracket group (n = 24), the straight wire bracket group (n = 15), and the Tweed-Merri ﬁeld edgewise bracket (n = 15). The results showed that the amount of IMPA was significantly different between the three groups after treatment and their mean values in the Damon group, straight wire brackets and Tweed-Merri ﬁeld edgewise were 92.05, 95.96 and 98.29 degrees respectively (14). In our study, in line with the aforementioned study, a significant difference was found between the MBT and the Damon brackets in terms of IMPA after treatment, which was higher in the Damon group. However, it should be noted that the IMPA was significantly higher in our study in the Damon group at the beginning of the study.

Fleming et al. conducted another study on 96 patients aged 16 years and older. They examined dental arches. The main purpose of their study was to compare the changes of inter canine, inter premolar and inter molar dimensions in the upper arch. No significant difference was observed between the three groups of active and passive self-ligating brackets and conventional brackets (12) which is in line with our study.

In another study, no significant difference was reported between post treatment IMPA in the conventional and Damon groups, which is contrary to the findings of our study. There was no significant difference in FMIA between conventional and Damon groups after treatment (P = 0.516). In our study, a similar result was obtained for the post-treatment comparison for FMIA. In addition, in their study, there were no significant difference between the two groups in the inter canine, inter first premolar, inter second premolar and inter molar width in the maxilla after treatment (15). However, Dolphin software was not used in their study, which reduces the accuracy of the study and could be the reason for some inconsistencies between the findings of this study and ours (15).

Atik et al. also compared three conventional systems: the conventional, passive self-Ligate and the active self-Ligate systems. Forty-six patients ranging from 13 to 17 years with moderate mandibular and maxillary crowding and class I malocclusion were compared. Only the distance between the second premolars was significantly different in the three groups and other measurements in the dental arches such as the distance between canines, first premolars and first molars were not statistically significantly different between the two groups. Also, U1-NA, IMPA and FMIA were not significantly different between the groups (9). In our study, similar to the mentioned study, the distance between the second maxillary premolars was significantly different between Damon bracket and MBT after treatment.

Due to the higher cost of Damon technique, its economic justification or cost-benefit had to be examined in order to obtain a convincing reason for using it.

Our study was performed on a very small sample compared to some other studies. Additionally, the retrospective nature of the present study has added to the limitations of controlling confounding factors.

#### 5.1. Conclusion

The aim of this study was to compare the two treatment systems of MBT and Damon regarding changes in the position of incisors and the dimensions of dental arches using the Dolphin software.

- Comparison of baseline mean values of landmarks and dental arches before treatment showed that, with the exception of IMPA˚, there was no significant difference between the two groups in this regard.

- Comparison of before and after treatment in Damon treatment system showed that only the mean U1Apog (mm), the distance between the maxillary canines and the distance between the second mandibular premolars before and after treatment were significantly different but no significant change was observed in incisors and dental arch position landmarks in the MBT group before and after the treatment.

- The results obtained after treatment in the two groups showed that the mean L1Apog (°), IMPA (°), distance between the first maxillary premolars, the second maxillary premolars, the maxillary canines and the distance between mandibular canines in the Damon group were significantly higher than the MBT group.

- Changes in the transverse dimensions of the maxillary and mandibular arches as well as the position of the upper and lower incisors after treatment were similar in both Damon and MBT systems.

### Footnotes

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