Separation of aligning and leveling stages to control mandibular incisor inclination: A randomized clinical trial

Abstract

Objective: To determine whether separating the alignment and leveling phases can reduce proclination of the mandibular incisors. Methods: Eligibility criteria included Class I subjects with an irregularity index of 3-5 mm, 3-4 mm curve-of-Spee (COS), and non-extraction treatment. Thirty adults were randomly allocated into two groups: (1) Control group was leveled and aligned simultaneously with flat archwires progressively to 0.016x0.022-in stainless-steel; (2) Experimental group was aligned first with 0.014-in-superelastic NiTi with mild accentuated COS, then leveled using 0.016x0.022-in beta-titanium accentuated COS archwires and gradually reduced the curve until flat. Mandibular incisor position and inclination were evaluated by cephalometric analysis. COS and irregularity index were evaluated in study models. Assessment was conducted twice after 0.016-in NiTi and after 0.016x0.022-in stainless-steel archwire placements. Dental changes from cephalograms and models were compared within group using paired t-test and between groups using independent t-test. Results: Control group: Round-wire-phase, mandibular incisors tipped labially (4.38° and 1 mm) with intrusion (-1.13 mm); Rectangular-wire-phase, mandibular incisors further intruded and proclined (-0.63 mm and 1.38°). Experimental group: During aligning with round accentuated COS archwires, mandibular incisors tipped very slightly labially (0.75° and 0.50 mm) with no significant intrusion; during leveling with rectangular archwires, incisors majorly intruded (1.75 mm) with slight proclination (1.81°). The experimental group had significant less incisor proclination (control: 5.76°, experimental: 2.56°) with more incisor intrusion (control: -1.75 mm, experimental: -2.13 mm). The COS in experimental group showed significant greater reduction (-2.88 mm) than that of the control group (-1.69 mm). Conclusion: In control group, mandibular incisor proclination was markedly observed in round archwires, with further proclination caused by rectangular archwires. In experimental group, minimal proclination was exhibited when accentuated COS round archwires were used for aligning. Leveling with rectangular archwires caused less proclination with more COS reduction.

Efficacy of lower arch leveling, lower incisors’ root resorption, and pain associated with the correction of curve of Spee using different orthodontic archwires: a randomized clinical trial

“…Although less lower incisor proclination in group 3 might be anticipated due to less bracket slot-AW play, this was not the case in this investigation. Lower incisor proclination might have occurred as the intrusive force application by reverse COS is anterior to the center of resistance [28]. This finding is in line with others who suggested that excessive incisor tipping may result from high intrusive forces at the incisor brackets creating tipping moments on each incisor and that could happen with increase AW dimensions [29].…”

Correlation between Depth of the Curve of Spee and Some Specific Malocclusion Characteristics in a Population from Sibiu County, Romania—A Cross-Sectional Study

“…To comprehend the impact of the depth of the COS on dental alignment, one must consider several elements, including the relationships between the anterior and posterior teeth [18], the angle at which the incisors are positioned [19], the patterns of vertical tooth eruption [20], and the functional alignment of the teeth during mastication [21]. These aspects illustrate how a pronounced COS can exacerbate malocclusions, affect tooth orientation, and influence vertical and horizontal teeth relationships [22], ultimately guiding the strategic approaches in orthodontic and restorative dental treatments [23].…”

Pemanfaatan ekstrak limbah biji Persea americana sebagai inhibitor korosi pada kawat ortodonti berbahan dasar Nikel titanium: Studi eksperimental laboratoris

“…Fase levelling dan aligning adalah keadaan mahkota gigi digerakkan dalam waktu bersamaan dan arah gerak yang berbeda. 5 Kawat NiTi memiliki sifat elastisitas dan shape memory effect yang baik. 6 Perawatan ortodonti bergantung pada kondisi kawat ortodonti.…”