vendex and Dental-Occlusion--Traumatic

In 13 healthy subjects (eight men and five women, mean age, 22 years), an aluminum intercuspal interference (height, 0.25 mm) was placed on the maxillary right first premolar to study its effect on the contractile symmetry of the right and left masseter and anterior temporalis muscles when measured through a Percentage Overlapping Coefficient (POC), derived from surface electromyographic recordings of maximum voluntary teeth clenching. Additionally, and to estimate the potential of the experimental intercuspal interference to induce lateral displacement of the mandible, a Torque Coefficient (TC) was derived from surface electromyographic recordings. The conclusion was that the experimental occlusal interference gave rise to asymmetric contractile activity in the studied mandibular elevator muscles as well as a potential to displace the mandible in a lateral direction.

Topics: Adult; Bicuspid; Bite Force; Dental Occlusion, Traumatic; Dental Stress Analysis; Electromyography; Facial Asymmetry; Female; Humans; Male; Masseter Muscle; Maxilla; Muscle Contraction; Reproducibility of Results; Stress, Mechanical; Temporal Muscle; Torque

Frontal plane mandibular rotations and corresponding hemimandibular translations were studied in vitro by using direct observations of a human cadaver mandible and in vivo by using the indirect observations of rotational electrognathography. A comparison between the two methods showed that rotational electrognathography erred in measuring the clinically relevant hemimandibular translations resulting from mandibular rotations having a unilateral molar point (simulated occlusal interference) as the pivot of frontal plane torque. In vitro frontal plane rotations about a unilateral mandibular molar tooth (simulated occlusal interference) suggested that the resulting hemimandibular upward translations of the lateral portion of the mandibular condyle, contralateral to the molar tooth, would cause considerable compressive loading of the temporomandibular joint disc.

Topics: Adult; Analysis of Variance; Biomechanical Phenomena; Bite Force; Compressive Strength; Dental Occlusion, Traumatic; Dental Stress Analysis; Electrodiagnosis; Female; Humans; Jaw Relation Record; Linear Models; Magnetics; Male; Mandible; Mandibular Condyle; Reference Values; Reproducibility of Results; Rotation; Signal Processing, Computer-Assisted; Software; Temporomandibular Joint Disc; Torque; Vertical Dimension