Are Currently Selected Laboratory Animals Useful in the Research of How Female Hormones Influence Orthodontic Biomechanics?

Animal testing was and remains the only method of introducing a certain treatment and medical procedure on humans. On the other hand, animals have their rights resulting from applicable legal acts, including Directive 2010/63/EU and, indirectly, the World Medical Association International Code of Medical Ethics (Helsinki Declaration, 1975, amended 2000). Thus, the question arises whether the credibility of the results of hormonal and orthodontic tests obtained so far and their usefulness for the human population is scientifically justified and worth sacrificing laboratory animals for. Especially that, according to statistical data, about 50% of laboratory animals are euthanized at the conclusion of the experiments. The aim of this article was to determine whether animal experiments are scientifically or morally justified in bringing significant evidence in studies that may validate the influence of changes in the concentration of female hormones secreted by the ovaries in various phases of the menstrual cycle in young patients on the duration of an increased tooth movement rate in orthodontic treatment. Papers reporting the results of the original research into female hormones, either natural or exogeneous ones, likely to alternate the orthodontic tooth movement rate were critically evaluated in terms of animal selection. Thorough analysis supported by veterinary knowledge proved that none of the publications enabled an extrapolation of the results to humans. The evaluation of the relation between the rate of tooth movement upon loading with orthodontic forces and hormones either secreted during the menstrual cycle of women or released from the contraceptives already present in the market, does not require sacrificing laboratory animals.

Orthodontic Treatment of Dogs during the Developmental Stage: Repositioning of Mandibular Canine Teeth with Intercurrent Mandibular Distoclusion.

Linguoverted mandibular canines are relatively rare among craniofacial abnormalities, and they are an isolated anomaly. They are most often caused by non-genetic factors such as persistent deciduous canine teeth or trauma coinciding with the eruption of permanent teeth. Another factor may be mandible narrowing or underdevelopment in the transverse dimension and vestibular inclination of the maxillary canine teeth. This article presents a procedure based on three cases where the position of the mandibular canine tooth was corrected using human orthodontic appliances modified to affect the canine dental system. The incline of the appliance was made to stimulate the protrusion of the mandible while the teeth were closing. After approximately 4 weeks, the lower canine teeth moved along the incline of the appliance, and tilt toward the flews was achieved.