Jaw Stability Research Articles

“Mandibular and facial reconstruction” rehabilitation of the head and neck cancer patient

As complex as Oral Cancer management is and as complex as the reconstruction and rehabilitation of its defects can be, there remains too much confusion about both its reconstruction and rehabilitation and far too great an acceptance of sub-optimal results than there ought to be. Today, the reconstruction of the cancer patient begins at the very time of the extirpative surgery. It should preserve certain native tissues which will function better than the very best reconstruction and yet no compromise the cure potential. It simultaneously includes jaw stabilization with rigid fixation plates and predictable immediate soft tissue reconstruction to allow adjunctive radiotherapy or chemotherapy to proceed while maintaining patient individuals appearance and supporting function. It then progress through definitive bony reconstruction, the gold standard of which today remains autogenous cancellous cellular bone grafting. Such grafts more consistently and truly reconstruct the jaws in preparation for a functional prosthesis than any other approach. Therefore, patients not only regain jaw continuity but also achieve an alveolar bone height and arch curvature which is permanent and thus allows the prosthodontist to align the dental occlusion correctly to the opposing arch. Today, the next step which follows achieving a definitive bony reconstruction is the placement of osseointegrated implants which integrate into the graft to provide a superb anchorage for a denture prosthesis and thereby increases the biting force capability of such appliances. Putting together this sequence of therapies has finally brought together successful reconstruction and rehabilitation with curative cancer surgery and its necessary adjuncts without their interfering with each other.

A potential mechanism underlying the voluntary suppression of Tardive Dyskinesia

Many clinicians have observed that patients with tardive dyskinesia (TD) can voluntarily suppress the movements to some extent. The mechanism by which voluntary control is exerted most likely involves peripheral feedback. Quantitative analyses of isometric and isotonic jaw stability were conducted in patients with and without TD to test the general hypothesis that involuntary movements of TD may be brought under voluntary control via one of two receptor mechanisms; muscle length and/or muscle force. Results indicated that in the absence of length feedback patients with TD exhibited significantly greater instability while patients without TD performed within normal limits. This suggests that patients with TD utilized muscle length feedback to suppress motor instability but were unable to utilize muscle force feedback to suppress instability. Implications for the use of laboratory procedures in the measurement and clinical management of TD are discussed.

The Mandibular Staple Bone Plate: Its Use and Advantages in Reconstructive Surgery

The mandibular staple bone plate is a reconstructive device that will attach to the inferior border of the mandible and will orthopedically provide for prosthetic and jaw stabilization in the edentulous mandible and the deformed mandible. It can be useful in a variety of clinical settings and is adaptable to a number of prosthetic needs. It is cost-effective and has demonstrated osteointegration in over 91 per cent of cases. The cumulative rate of success for 5 to 6 years is 94.6 per cent. 7

Ontogeny of oral function in hamsters (Mesocricetus auratus).

The oral apparatus of neonatal and juvenile golden hamsters was investigated by clearing and staining of whole crania, videotaping of behavior, and electromyography of several jaw muscles. Chewing developed during the first postnatal week and matured in the second; however, suckling was still the primary mode of feeding. Micromovements of the jaws occurred early when the osseous skeleton and joints developed. Macromovements correlated well with EMG records and were limited to jaw opening at birth. Muscles of the oral floor generated large bursts of activity during jaw opening and tongue protrusion from 0 days postnatal (dpn), when simple and stereotyped gaping was induced, until 14 dpn, when movements were spontaneous and not stereotyped nor inducible. However, adductor muscle activity was brief, low in amplitude, and primarily involved with jaw stabilization until 4 dpn, when these muscles became active during closing the jaws; closing activity increased in frequency and amplitude until the end of the second week. Development of frequent, coordinated macromovements of chewing was associated with the refinement of joint structure and dental occlusion and with the growth of the craniofacial skeleton. Jaw movements and associated EMG's correlated better with available data on development of neural circuitry than with that for musculoskeletal development.