In vitro Evaluation of Biomechanics of Orthodontic Aligners
Notice bibliographique
Résumé
In 2020, the dental care cost in Canada was approximately $13.89 billion and 20% of Canadians underwent orthodontic treatment. Patients seek orthodontic treatment to improve their oral functionality, psychosocial well-being, appearance, and quality of life. Aligner mechanotherapy is gaining popularity as an esthetic alternative to fixed labial mechanotherapy. However, the literature has reported limited treatment outcome with aligner mechanotherapy where 70-80% of orthodontic patients undergoing aligner treatment require midcourse correction, case refinement, or conversion to a fixed labial mechanotherapy before the end of treatment. This could be attributed to gaps in knowledge regarding aligner biomechanics that limits the predictability of orthodontic treatment outcome pointing towards the need to investigate biomechanics of the aligner mechanotherapy. The objective of the present thesis was to utilize in vitro methods (Orthodontic Simulator) to study the force system of aligners towards gaining a foundational understanding of their expected behavior in full arch treatments. Specifically, the fundamental factors such as tooth anatomy and position, aligner materials, and auxiliaries that could influence the biomechanics of aligner mechanotherapy were evaluated in this thesis. The initial experiments assessed the force system for different teeth (central incisor, canine and second premolar) by utilizing the most used aligner materials (polyethylene terephthalate, polyethylene terephthalate glycol, and polyurethane). The biomechanical knowledge was further advanced by subsequent experiments to evaluate the effect of varying the location of auxiliaries such as divots and attachments on aligner force system for bodily tooth movement and extrusion movement, respectively. There were several key observations made by series of biomechanical experiments. The initial experiment introduced the implication of tooth anatomy and tooth position in aligner biomechanics where mean buccal force and moment (that could tip teeth buccally/lingually) were significantly more for canine than for central incisor and premolar at 0.20 mm of lingual displacement. The similar trend was observed for other most used aligner materials: polyethylene terephthalate and polyurethane that exerted different force system on tested teeth. This experiment results highlighted the role of distinct underlying mechanical properties and variance in response of different materials to thermoforming process in aligner biomechanics. The results obtained from the experiments involving auxiliaries with aligner suggest that tactical placement of auxiliaries on buccal and lingual aspect of crown of incisors could improve the force system of aligners. This could mean possibility of extending the utility and application of aligners to difficult tooth movement such as bodily movement and extrusion. Overall, this in vitro evidence will improve understanding of force system of aligner mechanotherapy. The results will be instrumental in guiding the future research, influence the design and protocol of the aligner mechanotherapy that will improve the delivery of care by improving treatment outcome, and reducing the treatment time for orthodontic patients.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».