The influence of the leaf gauge and anterior jig on jaw muscle electromyography and condylar head displacement: a pilot study

Abstract

Background: A leaf gauge and an anterior jig may be used to assist the recording of a reproducible jaw position for restorative and prosthodontic treatment. This study investigated possible condylar displacement using an opto-electronic jaw-tracking device and a leaf gauge or anterior jig. The effect of a leaf gauge and anterior jig on jaw muscle electromyography was also examined. Methods: Five healthy adults without symptoms of temporomandibular disorders were selected. Condylar displacement during clenching were recorded simultaneously with electromyographic activity of superior and inferior heads of the lateral pterygoid, anterior and posterior temporalis, masseter, and suprahyoid muscles. Subjects were trained to bite at maximum and half-maximum biteforce using an anterior jig incorporating a force transducer. Results: No consistent condylar displacement was observed in x, y and z axes between different biteforces although there was a trend towards superior displacement. Comparison of maximum intercuspal clench and maximum clench on a leaf gauge and an anterior jig produced significant decrease in anterior temporalis activity (p<0.05), whilst an anterior jig with maximum clench significantly decreased posterior temporalis muscle activity. Conclusion: Within the limits of this pilot study, no consistent change in condylar position was identified with these appliances.Key words: Leaf gauge, recording technique, EMG, lateral pterygoid muscle.Abbreviations and acronyms: AJ = anterior jig; CT = computer tomography; EMG = electromyographic; IHLP = inferior head of lateral pterygoid; IP = intercuspal position; LG = leaf gauge; MIPT = mid-incisal point; SHLP = superior head of lateral pterygoid; TMD = temporomandibular disorders; TMJ = temporomandibular joint.

The effect of a Lucia jig for 30 minutes on neuromuscular re-programming, in normal subjects

“…Santosa et al 19 demonstrated that a neuromuscular device eliminates the posterior occlusal contacts, causing a de-programming of the proprioceptive memory of the periodontal ligament and promoting the relaxation of the masticatory muscles.…”

Bite forces and their resultants during forceful intercuspal clenching in humans

“…Indeed, posterosuperior condylar displacement reaches an average of 0.81 mm during maximal intercuspal clenching (Santosa et al;2006), whereas the amount of tooth movement under occlusal loads is less than 0.15 mm on average (Satsuma et al, 2002). The discrepancy between condylar and dental displacements can also cause the proximity of the posterior part of the mandibular corpus to the maxilla, and can contribute to the slanted bite-force distribution.…”

Evaluation of local muscle soreness treatment with anterior bite splint made of soft putty impression material

“…27 In addition, another research showed the use of ABS does not lead to the changes of condyles position with maximum bite force. 28 Some of literatures and researches also still recommend the use of ABS, but not more than 2 weeks with closely monitored. 4,11,24,29 For occlusal bite registration, this case report used MI position, because patients have complete teeth and stable occlusion.…”