Uprighting mesially tipped molars is often a necessary step before implant placement. However, the orthodontic treatment can be lengthy and discourage patients from choosing implant prostheses. Periodontally accelerated osteogenic orthodontics is reported to facilitate molar movements.
However, different combinations of corticotomy and osteotomy have found to have a biomechanical impact on orthodontic molar uprighting movements, suggests a study recently published in the American Journal of Orthodontics and Dentofacial Orthopedics.
This study aimed to evaluate the biomechanical effects of various corticotomy and osteotomy approaches on the uprighting of a mesially tipped mandibular second molar in a 3-dimensional finite element analysis model.
Corticotomy was introduced as a surgical procedure to shorten orthodontic treatment time. Corticotomy removes the cortical bone that strongly resists orthodontic force in the jaw and keeps the marrow bone to maintain blood circulation and continuity of bone tissues to reduce risk of necrosis and facilitate tooth movement.
The initial tooth displacement and periodontal ligament (PDL) strain in 9 finite element analysis models with various corticotomy and osteotomy simulations were compared under 3 intended tooth movement scenarios: distal crown tipping, mesial root movement with restraints, and mesial root movement without restraints. The impact of corticotomy and osteotomy on molar uprighting was studied.
The following findings were observed-
a. Corticotomy or osteotomy approaches altered the tooth displacement and the PDL strain in all 3 intended molar uprighting scenarios.
b. The 2 most extensive surgical approaches, the combined mesial and distal osteotomy with horizontal corticotomy and the circumferential corticotomy at root apex level, resulted in increased tooth movement but had a distinct impact on PDL strain.
As a result, the authors concluded that different combinations of corticotomy and osteotomy had a biomechanical impact on orthodontic molar uprighting movements.
They further inferred that corticotomy or osteotomy has altered the periodontal ligament strain during molar uprighting and that the results may contribute to an optimal treatment protocol for molar uprighting.
https://doi.org/10.1016/j.ajodo.2020.06.034