Anterior Hyperfunction by Mandibular Anterior Teeth: A Narrative Review.

"Combination syndrome", defined by Kelly in 1972, is a challenging condition observed in a patient with an edentulous maxilla and a partially edentulous mandible with only mandibular anterior teeth. "Anterior hyperfunction syndrome" is regarded as a synonym of combination syndrome and was first described in 1994. Although these terms have been well known, the definition of "anterior hyperfunction" has not been described yet. This narrative review focused on anterior hyperfunction and discussed the etiology and the clinical managements. An electronic bibliographic search for this literature review was conducted in addition to the review of our clinical cases. The previous reports indicated that combination syndrome with all five features was rarely observed. The patients with anterior hyperfunction generally showed the loss of posterior occlusal supports and the loss of vertical dimension of occlusion. To manage anterior hyperfunction, these conditions should be improved using conventional removable prostheses and implant-supported prostheses. Anterior hyperfunction is attributed to mandibular anterior teeth and some interventions for mandibular anterior teeth are required in many cases. Additionally, it must be noted that implant-supported prostheses may lead to anterior hyperfunction. In conclusion, comprehensive approaches for the remaining teeth and the prostheses will be required to manage this complex condition.