Forces and moments generated by aligner‐type appliances for orthodontic tooth movement: A systematic review and meta‐analysis

Abstract

The aim of this review was to systematically appraise the evidence on aligner mechanics and forces and moments generated across difference types of aligners. In vitro‐ laboratory studies for model simulated tooth movement with aligners. Database searches within Medline via Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), LILACS via BIREME Virtual Health Library. Unpublished literature was also searched in Open Grey, ClinicalTrials.gov (http://www.clinicaltrials.gov), the National Research Register (http://www.controlled-trials.com) and Center for Open Science (Open Science Framework), using the terms “aligner” AND “orthodontic”. Risk of bias assessment was based on the Cochrane Risk of Bias tool. Random effects meta‐analyses were conducted. A total of 447 studies were identified through electronic search and after careful consideration of pre‐ defined eligibility criteria, 13 deemed eligible for inclusion, while 2 were included in the quantitative synthesis. When palatal tipping of the upper central incisor through PET‐G aligners was considered, aligner thickness of 0.5, 0.625 or 0.75 mm was not associated with a significantly different moment to force (M/F) ratio, given a common gingival edge width of 3‐4 mm. Aligner thickness does not appear to possess a significant role in forces and moments generated by clear aligners under specific settings, while the most commonly examined tooth movements are tipping and rotation. The findings of this review may be applicable to certain conditions in laboratory settings.

Evaluation of the effects of diode laser application on experimental orthodontic tooth movements in rats. Histopathological analysis

“…Studies evaluated in the three groups were chemical applications, surgical applications and mechanical-physical applications. Agents such as acetyl salicylic acid 35 , 1,25-dihydroxycholecalciferol [7][8] , nitric oxide 9 , thyroid hormones 10 , and cortisone 11 , as well as prostaglandins have been used in the type of studies 12 . As surgical applications, corticotomy and similar applications are among the studies carried out to accelerate the orthodontic tooth movement.…”

“…In the literature review, it was observed that molars 19,20,23,24,[26][27][28][29]42,43 and incisors 7,25,35,[44][45][46] were used for experimental orthodontic tooth movement. However, Altan et al 25 used only incisors in rat studies in which low-dose laser was examined for experimental orthodontic tooth movements.…”

“…Many scientific studies have been done to solve this problem. For this purpose, many pharmacological agents have been used to accelerate orthodontic tooth movements, such as acetyl salicylic acid, dihydroxycholecalciferol 7,8 , nitric oxide 9 , thyroid hormones 10 , cortisone 11 , prostaglandins 12 , inflammatory cytokines 13 , osteocalcin 14 . In addition, orthodontic tooth movement was tried to accelerate by mechanical applications, such as mechanical vibration 15 , electrical current towards mechanical forces, pulsed electromagnetic field [16][17][18] , corticotomy 19 and laser applications [19][20][21][22] that have become widespread and developed in recent years.…”

Aparelhos ortodonticos invisíveis: uma revisão

“…Com relação à eficácia do tratamento, revisões sistemáticas sugeriram que essa modalidade de tratamento apresenta algumas dificuldades em movimentos ortodônticos específicos quando comparados a aparelhos fixos (Buschang et al, 2014, Djeu, 2005, Kuncio et al, 2007. De forma controversa e graças às propriedades mecânicas satisfatórias e aos avanços da tecnologia dos alinhadores, atualmente essa terapia é adequada para a correção de um amplo espectro de más oclusões (Beers et al, 2003), estudos tem observado que tanto o uso dos sistemas invisíveis quanto de aparelhos fixos tem fornecido resolução significativa no tratamento ortodôntico, considerando suas especificidades e indicações de tratamento (Balachandran, Ganapathy & Ramanatha, 2019, Iliadi, Koletsi &Eliades, 2019 .…”

ATR-FTIR Analysis and One-Week Stress Relaxation of Four Orthodontic Aligner Materials

“…The majority of manufacturers have changed the initially utilized thermoplastic material with polyethylene terephthalate glycol (PETG) and fabricate aligners of variable thicknesses. Regardless of the chemical compositions of the raw material used, the biomechanics [8][9][10] and the mode of action behind aligners remain similar. Specifically, every positioner is subject to deformation upon intraoral placement, and the initial magnitude of force placed on the teeth depends both on material stiffness and thickness as well as the intended tooth displacement prescription [11,12].…”