Orthodontics

21.Can lasers zap ortho alignment?

Could the use of low-level laser therapy (LLLT) enhance the efficiency of orthodontic dental alignment? Using 36 subjects, this interventional pilot study aimed to find out by randomly assigning them for treatment with a fixed appliance and LLLT (test group) or with fixed appliance only (control group). A single monthly administration of LLLT was performed using a Diode laser. The date of brackets bonding (T1) and the date of complete resolution of dental crowding (T2) were recorded. The alignment treatment time was defined in days as T2 - T1. Patients’ age, sex and amount of crowding were equally distributed between the two groups. The alignment treatment time was significantly shorter in the test group (211.8 days) compared to the control (284.1 days). Consequently, control visits were lower in the test group (7 visits) compared to the control group (9.5 visits). The results of this pilot study suggest that the administration of LLLT might significantly increase the efficiency of orthodontic treatment during dental alignment.

Caccianiga G et al. Does low-level laser therapy enhance the efficiency of orthodontic dental alignment? results from a randomized pilot study. Photomed Laser Surg  2017 2017 Mar 2. doi: 10.1089/pho.2016.4215. [Epub ahead of print].

Q Low-level laser therapy:
A Might significantly increase the efficiency of orthodontic treatment during alignment
B Had no effect on orthodontic treatment
C Was applied in this study on a weekly basis
D Caused significant gingival trauma during the orthodontic treatment

22.Recycling ortho brackets

This study aimed to assess bond strength of the resin/bracket interface, under in vitro shear stress, of metal brackets recycled by different clinical protocols by using 60 stainless steel orthodontic brackets bonded on acrylic resin. Samples were randomly divided into four groups by reconditioning/recycling protocol: AO - aluminium oxide 90 mum; HA60 - hydrofluoric acid 60s; HA120 - hydrofluoric acid 120s; HA60S - hydrofluoric acid 60s + silane. The resin was applied at the base of the bracket aided by a matrix, obtaining 1mm of thickness, and photo-activated. All brackets were then shear tested in a universal testing machine (0.5 mm/min). After reconditioning/recycling and testing the surfaces were analysed by Scanning Electron Microscopy. The AO group presented higher values of shear bond strength compared to the other reconditioning/recycling protocols. The HA120 and HA60S groups presented statistically similar results, but HA120 presented strength below the recommended limit. The recycling technique by aluminium oxide sandblasting was more effective for reconditioning orthodontic brackets.
 
de Oliveira Correia AM et al. Comparative assessment of different recycling methods of orthodontic brackets for clinical use. Minerva Stomatologica 2017 Mar 1. doi: 10.23736/S0026-4970.17.03984-X. [Epub ahead of print].

Q Orthodontic brackets:
A May not be recycled because of cross-infection considerations
B Give sufficient bonding strength when recycled using aluminium oxide sandblasting
C Should be recycled using hydrofluoric acid for two minutes
D Made of stainless steel are subject to fatigue after recycling and should not be reused

23.Obesity and speed of ortho

This prospective clinical cohort study investigated the effect of obesity on orthodontic tooth movement. Fifty-five adolescent patients (mean age 15.1 years) with mean body mass index of 30.2kg/m in obese and 19.4kg/m in normal-weight groups were followed from start to completion of tooth alignment with fixed orthodontic appliances. Outcomes were time taken to complete tooth alignment, rate of tooth movement and change in clinical parameters (plaque/gingival indices, unstimulated whole-mouth salivary flow rate, gingival crevicular fluid biomarkers). Data collection took place at baseline (start of treatment: appliance placement), 1 h and 1 wk following appliance placement, and completion of alignment. There were no significant differences between groups in time taken to achieve tooth alignment. However, at 1 wk, initial tooth displacement was significantly increased in the obese group, who also had a significantly higher rate of tooth movement compared with normal-weight patients over the alignment period. Analyses indicated that levels of inflammatory markers were significantly different between the groups and associated with observed rates of tooth movement. 

Saloom HF et al. Impact of obesity on orthodontic tooth movement in adolescents.
J Dent Res 2017 96: 547-554.

Q In this study, obese patients:
A Had a significantly higher rate of tooth movement
B Completed their alignment more quickly
C Failed to complete treatment compared to normal-weight patients
D Had more discomfort from the fixed appliances due to additional oral tissue

24.Lingual inclinations

Orthodontic or surgical proclination of lower incisors beyond a 100 limit increases the risk of inducing lingual gingival recessions. So concluded this research project which compared periodontal conditions in consecutive patients who had orthodontic treatment with proclination of lower incisors either by orthodontics alone (n=19) or in combination with anterior mandibular alveolar process distraction osteogenesis (DO) (n=18) with extraction of lower premolars (Ex), and 18 without extractions (Nonex). Radiographs, study casts and intraoral photographs were used to evaluate gingival recessions before (T1) and at 4.5 years (average) (T2) after treatment. No differences in labial recessions on lower incisors were present between the patient groups despite greater lower incisor proclination in the Nonex and DO groups. Severe lingual recessions (increased >1 mm) were more often present in the Nonex group (five sites; two subjects) compared to the Ex group (no sites). Proclination of lower incisors of 100 or more either by orthodontics or DO increased the risk of lingual gingival recessions 17 times but not labial gingival recessions.

Antonarakis GS et al. Gingival recessions of lower incisors after proclination by orthodontics alone or in combination with anterior mandibular alveolar process distraction osteogenesis.
Clinical Oral Investigations 2017 Jan 21. doi: 10.1007/s00784-017-2056-8. [Epub ahead of print].

Q Orthodontic or surgical proclination of lower incisors
A Causes labial gingival recessions whatever the resultant tooth angulation 
B Of 100 or more by orthodontics decreases the risk of lingual gingival recessions
C Of 100 or more by whatever method increases the risk of lingual gingival recessions
D Is contraindicated in all cases irrespective of periodontal condition