American Journal of Orthodontics and Dentofacial Orthopedics
Original articleIn-vivo von Mises strains during Invisalign treatment
Section snippets
Material and methods
In this prospective cohort study, we examined 61 aligners. Inclusion criteria were pure retraction of the measured maxillary central incisor (active dental unit) with no contact with the mandibular incisors and no movement of the measured anchored tooth (passive dental unit), interdental spaces around the retracted tooth, and increased overjet. These 61 aligners were selected from 117 maxillary aligners; 51 aligners were excluded from the study because other tooth movements were incorporated
Results
The treatment plan for patient 1 included closure of the diastema between the maxillary central incisors (9 aligners) and retraction of all 6 maxillary anterior teeth to reduce the overjet (29 aligners) (Fig 2).
Figure 3, A, and the Table give the mean values of IVM and PVM strains measured during maxillary incisor retraction treatment. Both variables (time and location) significantly affected the developed strains (P <0.001). Additionally, an interaction was found between time and location (P
Discussion
This study reports a novel in-vivo methodology to assess the force behavior of the Invisalign technique during retraction of the anterior segment, based on the assumption that the force exerted by the aligner on a tooth can be interpreted by the von Mises strains developed on the aligner surface. An additional set of aligners (series 2), used only for strain measurements, avoided moisture that could interfere with SG measurements.24 It can be suggested that changes that could occur in the
Conclusions
- 1.
A novel methodology was introduced to measure in-vivo strains during Invisalign treatment.
- 2.
Peak IVM strains developed at day 1, decreased at day 2, and maintained a plateau from days 2 to 15; this means that, in each aligner, most tooth movement (incisor) occurred within the first 24 hours.
- 3.
Because the von Mises strain level did not decrease to zero from days 2 to 15, this is probably related to undersized aligner manufacturing; even in a passive form, the aligner will exert some pressure on all
References (50)
- et al.
Automated custom-manufacturing technology in orthodontics
Am J Orthod Dentofacial Orthop
(2003) - et al.
Three-dimensional diagnosis and orthodontic treatment of complex malocclusions with the Invisalign
Semin Orthod
(2001) - et al.
The mechanical properties of dental thermoplastic materials in a simulated intraoral environment
Orthod Waves
(2006) - et al.
Orthodontic treatment with a series of removable appliances
J Am Dent Assoc
(2003) - et al.
Outcome assessment of Invisalign and traditional orthodontic treatment compared with the American Board of Orthodontics objective grading system
Am J Orthod Dentofacial Orthop
(2005) - et al.
Structural conformation and leaching from in vitro aged and retrieved Invisalign appliances
Am J Orthod Dentofacial Orthop
(2004) - et al.
Intraoral aging of orthodontic materials: the picture we miss and its clinical relevance
Am J Orthod Dentofacial Orthop
(2005) - et al.
Rapid palatal expansion. Part 3: strains developed during active and retention phases
Am J Orthod Dentofacial Orthop
(1998) - et al.
Biomechanical evaluation of the consolidation period of alveolar distraction osteogenesis with three-dimensional finite element analysis
Int J Oral Maxillofac Surg
(2008) The thickness of the human periodontal membrane
J Am Dent Assoc and Dent Cosmos
(1937)
Histomorphometric evaluation of alveolar bone turnover between the maxilla and the mandible during experimental tooth movement in dogs
Am J Orthod Dentofacial Orthop
Duration of elastomeric separation and effect on interproximal contact point characteristics
Am J Orthod Dentofacial Orthop
The effects of different storage conditions on polyether and time
J Am Dent Assoc
Dimensional accuracy of thermoformed polymethyl methacrylate
J Prosthet Dent
Influence of P/L ratio and peroxide/amine concentrations on shrinkage-strain kinetics during setting of PMMA/MMA biomaterial formulations
Biomaterials
In vitro study of frictional forces during sliding mechanics of “reduced-friction” brackets
Am J Orthod Dentofacial Orthop
A comparison of different ligation methods on friction
Am J Orthod Dentofacial Orthop
The Invisalign system in adult orthodontics: mild crowding and space closure cases
J Clin Orthod
SLA characterization for surface finish improvement: inverse design methods for process planning
A comparison of the periodontal health of patients during treatment with the Invisalign system and with fixed orthodontic appliance
J Orofac Orthop
A comparison of the periodontal health of patients during treatment with the Invisalign® system and with fixed lingual appliances
J Orofac Orthop
Clinical evolution of the Invisalign appliance
J Calif Dent Assoc
Influence of attachments and interproximal reduction on the accuracy of canine rotation with invisalign
Angle Orthod
A premolar extraction case using the Invisalign system
J Orofac Orthop
Four-premolar extraction treatment with Invisalign
J Clin Orthod
Cited by (43)
Physiochemical and mechanical characterisation of orthodontic 3D printed aligner material made of shape memory polymers (4D aligner material)
2024, Journal of the Mechanical Behavior of Biomedical MaterialsNumerical biomechanical finite element analysis of different trimming line designs of orthodontic aligners: An in silico study
2024, Journal of the World Federation of OrthodontistsEffect of oral exposure on chemical, physical, mechanical, and morphologic properties of clear orthodontic aligners
2023, American Journal of Orthodontics and Dentofacial OrthopedicsEffect of thermomechanical aging of orthodontic aligners on force and torque generation: An in vitro study
2023, Journal of the Mechanical Behavior of Biomedical MaterialsAn in vitro evaluation of aligner force decay in artificial saliva
2023, Journal of Dental SciencesEffect of trimming line design and edge extension of orthodontic aligners on force transmission: A 3D finite element study
2023, Journal of the Mechanical Behavior of Biomedical Materials
Supported by a grant from Align Technology, Santa Clara, Calif.
In partial fulfillment of the second author's requirements for the degree of master in orthodontics, Maurice and Gabriela School of Dental Medicine, Faculty of Medicine, Tel Aviv University.
The authors report no commercial, proprietary, or financial interest in the products or companies described in this article.