Angular and positional changes of the maxillary third molars after orthodontic treatment with different premolar extraction patterns.

OBJECTIVES: To evaluate the angular and positional changes of the maxillary second (M2) and third molars (M3) after orthodontic premolar extraction treatment according to patient skeletal classification and growth pattern. MATERIALS AND METHODS: Panoramic radiographs of patients treated with extraction of the first or second premolars (n = 116) and patients treated without extraction (n = 92), taken before orthodontic treatment (T0) and after completion of multibracket appliance therapy (T1) were analyzed. Angle classification, growth pattern, crowding, and incisor inclination were recorded. The palatal (PP) and interorbital planes (IOP) were used as reference lines. Changes in the M3 angulation relative to PP and IOP (T0-T1) within the same group were evaluated with paired t-tests. One-way analysis of variance (ANOVA) and Kruskal-Wallis tests were used for comparisons between the groups. Accordingly, pairwise comparisons were performed with Mann-Whitney U-tests or independent t-tests (P < .05). RESULTS: The M3 angulation related to the PP and the IOP did not differ significantly between the extraction and nonextraction groups. The M2 angulation improved in the premolar extraction group between T0 and T1 (M2/PP, P < .001). According to Archer's classification, the change in the vertical position of M3 differed significantly between the extraction and nonextraction groups (P < .001). CONCLUSIONS: The angulation of M3 improved over time regardless of the extraction decision. The vertical eruption pattern of M3 was positively influenced only in the extraction group. M2 became significantly more upright in the orthodontic extraction treatment groups.

Effects of Sabbagh Universal Spring 2 fixed functional appliance on class II/1 patients at their postpubertal-peak growth period compared with the extraction method : A randomized clinical trial.

OBJECTIVE: The aim of this study was to evaluate the therapeutic effects of the Sabbagh Universal Spring 2 (SUS 2) fixed functional appliance compared to the premolar extraction method in correcting class II/1 malocclusion in patients who had passed their peak of postpubertal growth (stages 4-6 of Cervical Vertebral Maturation Index). METHODS: In all, 40 class II/1 patients were randomized to receive SUS 2 application (7 males, 13 females, age 15.75 ± 1.02 years) or maxillary premolar extraction (8 males, 12 females, age 15.40 ± 0.99 years). Pre- and posttreatment digital cephalographs were traced at least twice. A paired t test was used to compare the pre- and posttreatment measurements. Treatment changes were compared using an independent samples t test (P ≤ 0.05). RESULTS: The extent of change was significant in the following variables: ANB, nasolabial angle, Mand1-ML, 1L-NB, anterior and posterior facial heights, N-A-Pog, 1U-NF, 6L-MP, Ar-Go, OP-HP, A-B, A-Sn, B-Sm, APDI, NAPog, AB-NPog, POr-DOP, SN-OcP, POr-OcP, Wits, 1 l-APog, 1LMeLm, S-Go:N-Me, N-ANS-Pog, Ap1LAp1u-DOP, ANS-Cond, Pog-Cond, SS-Ls, A-N-Pog, Pog-Pog', MeGoOcP, 1L-Npog, Go-Me, Go-Me:N-S, S-Me, Ls-(Sn-Pog'), Stms-Stmi, N'-Gn', N'NsPog', 6u-PTV, 1u-NA, FMIA, and IMPA. CONCLUSIONS: SUS 2 corrected class II/1 malocclusion of patients in the postpubertal growth period by inhibiting the maxilla's forward growth, advancing the mandible, decreasing the nasolabial and interincisal angles, proclining the incisors, increasing the facial height, and clockwise rotation of the occlusal plane. Extraction reduced the interincisal angle and protruded the lower incisors. However, it did not change the soft tissue thickness and did not cause a clockwise rotation in the occlusal plane.

Effect of maxillary premolar extraction on transverse arch dimension in Class III surgical-orthodontic treatment / 대한치과교정학회지

Collective changes caused by orthodontic tooth movement evaluated in a specific treatment modality could give suggestive information on the specific treatment strategy. The aim of this study was to investigate retrospectively the characteristics of the orthodontic tooth movement during surgical-orthodontic treatment in order to provide an effective presurgical orthodontic treatment planning for the maxillary premolar extraction modality in the skeletal Class III malocclusion patient. Pre- and posttreatment dental casts of skeletal Class III malocclusion patients with nonextraction (N=24) and the maxillary premolar extraction (N=31) were collected. The angulation and inclination measuring gauge (Invisitech Co. Seoul, Korea) was used to evaluate the orthodontic tooth movement. The changes in the maxillary and mandibular dental arch widths were also measured from the canines to the second molars. As a result, more palatal inclination change in the maxillary dentition was found with the premolar extraction modality than with the nonextraction modality. Linear regression analysis showed that the inter-arch width coordination was mainly due to the inclination changes of maxillary posterior teeth. We conclude that the indications and proper treatment planning for surgical-orthodontic treatment in skeletal Class III malocclusion with maxillary premolar extraction could depend partly on the magnitude of the transverse inter-arch coordination especially in the maxillary dentition.