Total Alloplastic TMJ Replacement
Who Need Total Alloplastic TMJ Replacement?
TMJ reconstruction represents a unique clinical challenge, as TMJ plays an important role in the mastication, phonation and respiration functioning of the jaw. In addition the secondary mandibular growth center lies within TMJ. Since the 80', the clinicians have been kept on searching for effective and feasible way of TMJ reconstruction for patients with TMD caused by various reasons, including maxillofacial deformities, trauma, tumor resection and articular ankylosis, to reach the following goals:
Development of TMJ reconstruction
On the historical development of TMJ reconstruction, much waste efforts has been made before people have come to the conclusion that patient-fitted TMJ prosthesis is the most reliable and stable option. The reason is that it is impossible to restore 100% of TMJ functioning to its original condition due to the special anatomical structure of TMJ and its highly complicated relation with the masseters. Different autogenous tissue has been used to reconstruct TMJ in various researches, including fourth metatarsal (Bardenheur, 1909; Gillies, 1920), rib cartilage (Fukuta,1992；Guelnick,1996), iliac crest (Talor,1982), clavicle (Snyde,1971；Siemssen,1982). In the early 90', costochondral graft and sternoclavicular graft were commonly used in TMJ reconstruction and considered to have high growth potential and therefore suitable for use in younger patients. However TMJ reconstruction with autogenous tissue requires a second incision and may result in excessive cartilage growth and even intra-articular adhesions leading to secondary operation. In addition, in case of patient underwent multiple joint surgeries (more than 2 times) or had high-inflammatory arthritis, the success rate of autogenous tissue transplantation becomes significantly low (Lindqvist,1988;Matsuura,2001)
For all these shortcomings, in particular the unpredictability of the autogenous tissue (absorption? growth? recurrent adhesion?), the development trend of TMJ reconstruction is toward alloplastic, just like in orthopedics. Experts recommended early consideration of alloplastic reconstruction, which means the success rate of first time TMJ reconstruction with alloplastic joint is much higher than that of secondary TMJ construction with alloplastic joint.
Alloplastic TMJ Joint
Historical development of alloplastic joint techniques can be traced back to in the 60's. Orthopedic surgeons applied alloplastic joint techniques for the first time in total hip replacement surgery. With the technological advances and progress in material science, stability and durability of alloplastic joint has gradually increased. For any kinds of alloplastic implant (e.g. artificial dental implant, alloplastic joint), good osseointegration is the key to achieve long-term stability and good osseointegration comes from secure implant primary stability. Stable fixation of the artificial hip joint to the long bone marrow is well achieved by press fitting or cementation. Due to the limitation from anatomical structure of TMJ, good fixation stability can only be achieved by screw fixation.
In order to achieve good joint stability, avoid implant micro-motion that destroys primary stability and results in the failure of osseointegration, our team chooses to use the patient-fitted TMJ prosthesis (TMJ Concepts devices) which have proven to have the best clinical success rate (>85% within the 20-year follow-up period).
Ultimate choice- Patient-fitted TMJ Prosthesis: TMJ Concepts
Development of TMJ Concepts patient fitted TMJ prosthesis started in 1989 and was granted US FDA approval in 1996. Custom TMJ device components are designed and manufactured with CAD-CAM technology. Based on individual patient's 3D skull model, the custom implant can fit perfectly to the patient's anatomical structure. The application of patient-fitted TMJ prosthesis shortens surgery time, requires no second incision, grants the fast recovery from surgery and decreases the risk of developing re-ankylosis (Wolford LM,1994,2015; Granquist EJ,2011; Mercuri LG, 1995)。
Based on the latest study investigating 111 patients who received TMJ Concepts patient-fitted TMJ prosthesis for more than 20 years, the TMJ pain index, mandibular function, masticatory function and maximal mouth-opening extent were significantly improved. More than 85% of the patients reported to have improved quality of life and none experienced removal of alloplastic joint due to any material wear, loose or breakdown, which proved its long-term stability property (Wolford,2015)。 In conclusion, patient-fitted alloplastic TMJ prosthesis requires no second surgical incision, shortens the surgery time and hospitalization period and achieves higher success rate compared to autogebous bone graft. Recent studies reconfirmed its long-term stability and high success rate. Therefore although patient-fitted alloplastic TMJ prosthesis is more costly than autogenous tissue, it remains the best choice for TMJ reconstruction.
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All Written Contents and Pictures Created by Dr. Adrian M. Hsieh and Dr. Scott H. Jiang
Aesthetic Medicine Department Plastic Surgery DepartmentAesthetic Dentistry Department
Results of surgery vary among patients. Please consult your doctor.
