The patient was an 18-year-old man with the chief complaint of dental crowding. There were 9 and 10-mm arch-length discrepancies in the upper and lower arches, respectively.
Pretreatment facial photographs showed a convex profile, vertical facial proportions were normal, and there were no significant asymmetries. He had some carious teeth and upper right first premolar had already been extracted.
In centric relation, the right molar was class II, whereas the left molar relationship was class I (
Figure 1). The mandibular midline deviated 3 mm toward the left. The patient had normal overjet and overbite.
Figure 1. Pre-Treatment Extra Oral and Intra Oral Photographs of Patient
Figure 2. Unfortunately, in Maxillary Right Side, the Secondary Molar Was Extracted by Mistake, So Our Treatment Plan Changed, and We Had to Distalize Maxillary Right First Molar
Figure 3. Distalization Appliance
Figure 4. Distalization Appliance After Insertion
Figure 5. Post-Treatment Extra Oral and Intra Oral Photographs of Patient.
Figure 6. Refrence Lines for Measurment of Molar Distalizaton
Figure 7. Superimposition of Pre-Treatment and Post- Treatment Lateral Cephalogram Shows 3 mm Upper Molar Distalization
Figure 8. Pre-Treatment and Post-Treatment Intraoral Photographs Show First Molar Position.
In pretreatment cephalometric evaluation (
Table 1), the maxilla was normal to the cranial base (SNA 83°), and in centric occlusion, the mandible was in normal position to the cranial base (SNB 80°). The ANB (3°) indicated a class I skeletal relationship. Protrusion of lower incisors was detected in cephalometric radiograph (IMPA, 100).
Based on these findings, the patient was diagnosed with skeletal class I malocclusion with asymmetric molar relationships (
Table 1. Pre-Treatment and Post-Treatment of Cephlometric Variables
Variables Norms Pretreatment Posttreatment SNA 82 83 83 SNB 80 80 80 ANB +2 3 3 U1-SN 103 103 102 IMPA 91 100 96 Interincisal anngle 131 126 130 FMA 25 23 26 GoGn-SN 32 30 32 Gonial angle 125 125 125 LAFH 72 74 LAFH/TAFH, % 55 55 56 Jaraback index, % 62-65 63 64 2.1. Treatment Objectives
The treatment objectives for this patient were to:
(1) Relieve the crowding, which was his chief complaint, (2) Eliminate lower incisors protrusion, (3) Establish class I molar and canine relationships, and (4) Correct the mandibular midline shift.
Our treatment plan was a nonsurgical approach with extraction of the maxillary right first molar, maxillary left first premolar, mandibular right first molar and mandibular left second premolar. Unfortunately, in maxillary right side, the secondary molar was extracted by mistake of his dentist.
2.2. Treatment Progress
Before the orthodontic treatment, the patient was referred to extract intended teeth, unfortunately, the upper right second molar was extracted instead of the first molar (
Figure 2), so our treatment plan changed, and we had to proceed with distalization of maxillary right first molar.
Upper first molars were banded and 022 Roth brackets were bonded on all maxillary and mandibular teeth. Two mini-implants (2x8-mm, Jail Medical Corp, Korea) were inserted in palate 1 - 2 mm aside of the midpalatal suture at the height of the contact point between the first molar and second premolars. After leveling and aligning teeth up to 0.019x0.025” stainless steel, an impression was obtained with the screw in place, and a plaster model was prepared. The distalization appliance was also made (
Figure 3). Our distalization appliance was made of two wire parts and an acrylic button. Wire components are made of 0.036-inch stainless steel. After making these components, an acrylic button was formed and the site of mini-screws was perforated.
End portions of appliances were inserted in lingual sheets of maxillary first molar bands. Acrylic button was then fixed on screws by self-curing composite resin intraorally (
In this stage, two portions of appliance were joined by ligature wire on the right side. The patient was checked every 4 weeks, and the force level of the activated appliance was checked and activated when necessary. The patient was instructed to brush the appliance with mild pressure so that no irritation would occur, and oral hygiene around the implant would be maintained. When upper right first molar was moved into an overcorrected class I relationship, the distalization ended. Molar distalization was completed in 6 months.
In lower arch, midline correction was done by a miniscrew between canine and first premolar on the right side.
2.3. Treatment Results
The insertion procedure of the screws was quick and simple. The patient reported no pain requiring analgesic either after the insertion or during the distalization period. The screw was stable right after the insertion. Crowding, which was the patient’s chief complaint, was eliminated at the end of the treatment. The midline deviation was corrected, and the dental midlines were aligned with the facial midline (
Figure 5). The posterior occlusal relationships were improved to achieve class I canine and molar relationships on both sides. The right upper first molar was successfully distalized and the required space for upper crowding was gained. Distalization time was 6 months. Ideal overjet and overbite were established and correction of the malocclusion was accomplished with dental movements. The post treatment cephalometric analysis is given in the Table 1. 2.4. Cephalometric and Model Analysis
At the end of the treatment, we drew midpalatal raphe in pretreatment and post-treatment models. Then distal to rugae, a reference point was selected and a line, which was perpendicular to midpalatal, was drawn in the two models. Another perpendicular line was drawn from mesial marginal ridge of right first molar. The distance between these two perpendicular lines was measured (by calculating magnification of photos) (
The maxillary right first molar distalization was 2.7 mm. Distalization was done by bodily movement of maxillary first molar (
Figure 7). The remained class II molar relationship was corrected by mesial movement of mandibular right first molar. First molar position is shown in pre-treatment and post-treatment intra oral photographs ( Figure 8).
Measurement of central incisor angle to SN shows that proclination of incisors has not happened. (
Table 1) As seen in the Table 1, there is a slight increase in vertical dimensions (LAFH), which is one of the major side effects of conventional molar distalization appliances ( Table 1).