Modern Temporomandibular Joint Surgery: A Review

Rebeka G. Silva, DMD; Stephen T. Connelly, DDS, MD, PhD; and Kenneth A. Holman, DDS

ABSTRACT

Background: The temporomandibular joint (TMJ) is a complex, load-bearing structure that may require surgical modification or reconstruction, depending on the diagnosis, chronicity and level of dysfunction.

Methods: Broad categories of temporomandibular disorders (TMD), including myofascial pain, internal derangement (ID) and degenerative joint disease (DJD), are outlined. While traditional treatment of TMD is generally limited to conservative and reversible regimes, the TMJ surgeon may bypass conventional treatment in favor of surgical options. Surgical decision-making and a variety of surgical treatment for ID and DJD, among other disorders, are reviewed. Surgical options include intra-articular surgery and total joint reconstruction. The role of splint therapy for surgical and nonsurgical patients is also discussed.

Results: Specific TMJ disorders benefit from a surgery-first approach to achieve mandibular and occlusal stability. Selected patients may be offered TMJ surgery in lieu of conservative therapy in the setting of symptomatic ID, severe DJD, ankylosis, condylar fracture, primary joint pathology and in the context of a co-diagnosis of obstructive sleep apnea and joint degeneration for those who require maxillomandibular advancement.

Practical implications: General dentists and dental specialists often manage TMD patients with a variety of conservative treatments but may miss an opportunity to obtain an early surgical opinion from a TMJ surgeon for patients with specific signs and symptoms. The traditional TMD treatment pyramid does not always apply; therefore, the surgery-first paradigm may help get patients prompt definitive care.

Key words: Temporomandibular joint, TMJ surgery, TMJ reconstruction, degenerative joint disease, internal derangement

AUTHORS

Rebeka G. Silva, DMD, is a Clinical Professor of Oral and Maxillofacial Surgery at the University of California, San Francisco. She is a board-certified oral and maxillofacial surgeon and practices in a private practice and in the Oral and Maxillofacial Surgery Section, Dental Service, at the San Francisco VA Healthcare System.

Stephen T. Connelly, DDS, MD, PhD, is Associate Clinical Professor of Oral and Maxillofacial Surgery at the University of California, San Francisco. He is a board-certified oral and maxillofacial surgeon and practices in a private practice and in the Oral and Maxillofacial Surgery Section, Dental Service, at the San Francisco VA Healthcare System.

Kenneth A. Holman, DDS, maintains a private orthodontics practice in Redwood City, Calif.

Conflict of Interest disclosure for all authors: None reported.

The evolution of temporomandibular joint (TMJ) surgery has taken oral and maxillofacial surgeons on a long journey that includes direct surgical procedures on the joint complex (through disc surgery, arthroplasty and joint replacement) and surgery that indirectly affects the relationship of the joint-disc relationship (condylotomy). Due to the beautiful yet complex anatomy and function of the TMJ, many oral and maxillofacial surgeons do not choose to incorporate TMJ surgery into their clinical practice. The surgeon who takes a patient to the operating room to modify or replace the physical condyle-disc-fossa relationship without fully understanding or addressing the underlying reasons for the joint pathology risks poor outcomes, relapse and/or the need for additional surgery. Nevertheless, we can all agree that there is a need for competency in TMJ surgery and that many clinical situations exist that demand a surgical plan. Therefore, it is the intent of this paper to provide insight into the surgical decision-making process and to update the reader on some of the surgical interventions that are part of the TMJ surgeon’s armamentarium. Postoperative splint therapy following TMJ surgery and for nonsurgical candidates will also be reviewed.

Background

A variety of independent and overlapping maladies exist in our surgical candidates, and these are dealt with through the involvement of many of our nonsurgical colleagues, including the general dentist, the orthodontist, the primary care physician, the physical therapist and the mental health provider. Once the patient is referred to the surgeon’s office, perhaps due to a poor or incomplete response to a variety of interventions, the hard work begins to precisely determine the principal underlying problem that may be amenable to surgery. One way to approach this is by considering that most TMD patients fall neatly into one of the following three camps:

■ Those with myofascial pain (MFP), muscle spasticity, trigger points, fibromyalgia, etc.

■ Those with an internal derangement (ID), also known as disc derangement, that alters the mechanics of normal joint function.

■ Those with degenerative joint disease (DJD), characterized by arthrosis or different types of arthritis.

Other categories of TMJ conditions are less frequently encountered but surgery is often indicated and is in the patient’s best interest:

■ Congenital deformities of the joint, including absence of the joint.

■ Presence of a pathologic lesion within the joint, the mandible or oral cavity that would affect the integrity of the joint either directly or by virtue of the jaw reconstructive surgery needed.

■ Mandible fracture that has affected the joint or ramus.

■ Joint hypermobility.

■ Joint ankylosis.

Looking at the three major categories above, the TMJ surgeon endeavors to determine which diagnosis predominates, because blended problems are common and a source of confusion. If the myofascial category is predominant, the patient is not a surgical candidate unless successful treatment of the soft tissue pain exposes an underlying physical problem. If the internal derangement category predominates, the patient might be a surgical candidate if jaw function is adversely affected, there is significant discomfort in capturing or failing to capture the disc, the chronicity of the disc problem suggests spontaneous improvement is not likely and/or there is lack of treatment success by other means. The TMJ MRI is commonly used to visualize the fossa-disc-condylar head relationship ( FIGURES 1). Similarly, if the degenerative joint disease category predominates, the patient might be a surgical candidate based on jaw function and pain at the joint head, the severity of bony erosion or whether occlusal issues have developed secondary to joint erosion. A highresolution CT or CBCT scan is used to visualize degenerative changes of the condylar head and articular fossa.

For the purposes of this manuscript, it is not necessary to explore all the components of the surgical decision tree, but it should be understood that the patient always comes first and that the leap to a surgical treatment plan is never taken lightly. That said, however, TMJ surgeons are frequently frustrated by the concept held by many, including insurance companies, that surgery is the treatment of last resort and that it resides at the top of a broad pyramid of nonsurgical modalities to treat TMD. For quite a few patients, we must turn that pyramid upside down and consider a “surgery-first” approach so that the rest of the treatment plan, be it orthodontics, dental rehabilitation or treatment of some other disease entity, can be carried out.

“Surgery first” may be a novel concept for many readers, but the following scenarios will illustrate some of the situations where it is indicated:

■ TMJ fibrous or bony ankylosis. The TMJ anatomy and jaw function are so compromised in these cases that no amount of conservative therapy could be reasonably expected to make a difference. Total joint reconstruction is indicated.

■ Displaced high condylar fractures or intracapsular fractures, especially bilateral injuries. When patients have unfavorable condylar trauma, with the fracture right below the condylar head or within the joint head, open reduction and stabilization of the fracture is not possible. Patients often have a significant shift in occlusion due to shortening of the ramus on the affected side; those with bilateral unfavorable condylar fractures develop anterior open bites that resist correction. Unilateral (or bilateral) total joint reconstruction is often indicated.

■ Symptomatic severe degenerative joint disease. There is no longterm fix for severe degeneration with pain secondary to inflammation. These patients, especially those with progressive autoimmune arthridities, are either successfully medically managed or they are not. If a patient with advanced bony deterioration desires surgery to improve joint function, prevent further deterioration or correct malocclusion through orthognathic surgery, it is reasonable to proceed with TMJ surgery. We do not currently have the technology to resurface destroyed joint articulations, therefore many of these patients undergo total joint reconstruction.

■ Longstanding disc displacement without recapture interfering with jaw function, especially if with evidence of disc degeneration or perforation. A disc that has a perforation will never heal.

■ Primary TMJ pathology. Cysts, tumors and other primary pathologies of the TMJ are not common but must be addressed surgically. Patients with aggressive or malignant mandibular pathology may require excision of the lesion along with the entire ramus and joint complex. Reconstruction is indicated.

■ Dual diagnoses of severe obstructive sleep apnea (OSA) and joint degeneration. If maxillomandibular advancement (MMA) surgery is planned in order to open the airway, stable joints are required to prevent relapse. MMA surgery is highly efficacious in severe OSA, but successful mandibular advancement depends on stability of the joints, which serve as the bony struts that maintain the mandibular position. Ongoing TMJ deterioration can result in a backward slide toward Class II occlusion, anterior open bite and associated soft tissue collapse of the airway volume.

The future of TMJ surgery is bright, with research groups working on custom bone options based on individualized stem cell constructs through bioengineering breakthroughs. Although the authors believe there will always be a role for prosthetic joint replacement, the promise of scaffolds and stem cells engineered to precisely reproduce the anatomic defect will likely be a large part of the future of cranio- and maxillofacial surgical reconstruction. It is exciting to know that reconstructive surgeons are closer than ever to having this in their surgical armamentarium, especially as the first custom bone replacement constructs for the craniofacial skeleton are undergoing animal testing and at least one has received approval for a first-inhuman clinical trial. Adult mesenchymal stem cells (MSCs), particularly those derived from human adipose tissue, may be induced to form chondrocytes and osteoblasts. These cells are grown in osteogenic media, and a scaffold, the shape of which is determined through patient-specific CT scan-based virtual surgical planning, serves as the blueprint for custom bone replacement. Much work is also being done in the domain of articular disc replacement, because the TMJ is a load-bearing joint and requires a buffer between the condylar head and fossa to prevent destructive remodeling. The fibrocartilage composition of the TMJ articular disc, with close to 1-to-1 ratio of type I and II cartilage, presents a challenge to the bioengineering community. [1] Synoviumderived mesenchymal stem cells have been found to have the greatest potential to undergo chondrogenesis when combined with specific growth factors. [2]

Disc Surgery

The normal disc position allows smooth rotation and translation of the joint yielding a full range of motion. Many patients with disc displacement have joint noise with function, especially with opening, but depending on the dynamic displacement of the disc, joint noise with lateral movement or closing movement is possible. This is known as disc displacement with reduction. In the acute phase of an anteriorly displaced disc, pain with movement directly over the joint head or in the ear is a frequent complaint, and this is often accompanied by a subtle change in occlusion due to edema within the joint. Patients may describe a slight open bite on the affected side or a mild shift in their occlusion toward the opposite side. If the disc does not spontaneously reposition on its own or through conservative measures, some patients over time will develop a “pseudodisc” of the retrodiscal tissues that tethers it to the tympanic plate behind the joint. This pseudodisc transformation of the normally delicate retrodiscal tissue forms through very gradual replacement of tissue containing blood vessels and nerves with more fibrous tissue and has the patient feeling more comfortable and often permits a return to full or near full range of movement. Those patients with chronic displacement with reduction who cannot get pain relief or have intermittent impeded jaw movement show up in the surgeon’s office looking for solutions. Likewise, patients with displaced discs so distorted or out of position that the condylar head can no longer slip under it with opening (disc displacement without reduction) may find their limited jaw movement and discomfort to be unacceptable, prompting them to seek a surgical remedy.

The Wilkes classification, developed in 1989, is considered by many to be the gold standard for stratifying TMJ internal derangements (TABLE). It takes into account disc position, level of pain, joint noise, inflammatory soft tissue changes of the disc and degenerative bony changes of the joint head. In evaluating the clinical and imaging findings, a surgeon can determine the best surgical course.

Open approaches to disc surgery have their specific indications, and the choice of operation is based on diagnosis and surgeon’s experience. Open-joint surgery involving the disc has as its goal either the improvement of the condylar head-disc-fossa relationship through disc repositioning or the removal of the disc as a physical obstacle to normal joint movement through discectomy, typically with disc replacement using other tissue. If the disc is noted to be dislocated but intact on MRI, the TMJ surgeon may attempt to surgically reposition it over the joint head. Although discs can become dislocated in any direction relative to the joint head, it usually dislocates medial and anterior to the joint. If the disc is perforated or grossly abnormal, it cannot be meaningfully salvaged and discectomy becomes the surgery of choice.

Discectomy

Discectomy without disc replacement for the diagnosis of internal derangement has a long history, generally reported as successful, but often results in dramatic long-term remodeling known as arthrosis, adaptive change not necessarily accompanied by pain and inflammation and presumably due to bone-againstbone contact from lack of intervening tissue. [3,4] However, the narrowing of the joint space after discectomy will produce a premature occlusion on the ipsilateral side and joint noise such as crepitus is common, arising from cartilaginous degenerative changes known as chondromalacia. [5,6] In fact, contour changes will be noted at the glenoid fossa in addition to the condylar head, but if these changes are not painful or limiting, they may not be of clinical significance. The holy grail of discectomy for many TMJ surgeons has been to find a suitable biologic tissue that has the toughness and resiliency to cushion the joint and mitigate arthrosis due to the forces that are placed upon it. Among the various biological tissues that have been studied are temporalis muscle, fascia, fat, dermis and auricular cartilage. The temporalis flap technique is of interest because it is a pedicled flap that is divided from the temporalis muscle, along with the overlying fascia, and swung down into the fossa to be interposed between the joint head and the fossa after removal of the disc. Because the temporalis tissues retain blood supply, but not nerve innervation, this technique differs from all other interpositional tissues that are essentially free tissue grafts.

Disc Repositioning

Disc repositioning is the traditional way of improving the condylar-meniscal relationship when the disc can be documented as displaced. There are various techniques to accomplish this, including resection of excess or lax retrodiscal tissue to pull an anteriorly displaced disc back into position or imbrication, which is accomplished without resection of tissue. One or two small titanium anchors embedded within the condylar head are useful to stabilize displaced discs with sutures threaded through the bone anchors, [7] but there is doubt that long-term stability can be achieved with any technique

( FIGURES 2). Our group has more recently reported on the successful use of viable cryopreserved umbilical tissue (vCUT) and cryopreserved viable osteochondral allograft (CVOCA) as an interpositional biologic material in discectomy cases ( FIGURES 3). The construct is stabilized to the surface of the fossa to act as a fossa liner through the use of deep sutures medial to the condyle and bone anchors embedded into the lateral edge of the articular fossa, rather than to the joint head. [8]

Arthroplasty

Another type of surgery within the joint complex is arthroplasty, which literally means “reforming of the joint.” Eminectomy, the removal or reduction of the articular eminence with or without disc repositioning, is a surgery designed to create more space and allow unimpeded movement of the condylar head in cases of hypermobility when frequent dislocations are noted. Joint laxity can cause the trapping of the condylar head in front of the articular eminence, and if the patient cannot manage to self-reposition their TMJ back into the fossa, assistance is often sought in the emergency room setting. Arthroplasty also includes procedures to surgically smooth irregularities of the joint surface and of the fossa.

Total Joint Reconstruction

Many readers may be familiar with the troubled history of alloplastic materials used in TMJ surgery. Meniscal and total joint devices that were in use between the 1970s and 1990s were faulty; failures and lawsuits abounded. Serious problems with these older devices no longer in use included foreign-body reaction to particulated Teflon-Proplast, fracture of the prosthesis or metallosis from In 1999, when the U.S. Food and Drug Administration granted TMJ Concepts (Ventura, Calif.) full approval for its patient-specific prosthesis under the 510(k) provision, TMJ surgeons worldwide saw this as a turning point in total joint replacement (TJR) surgery. Another device, which comes in a variety of stock sizes and angulations manufactured by Biomet Microfixation (Jacksonville, Fla.), gained FDA approval in 2005. TMJ surgeons in the U.S. finally enjoyed the freedom to select between a custom versus stock TMJ prosthesis, both of which were designed and manufactured on the orthopedic principles and materials that are the current standard of care in hip and knee prostheses.

The indications for total joint reconstruction include:

■ Articular disc dislocation.

■ Adolescent internal condylar resorption.

■ Reactive arthritis.

■ Condylar hyperplasia.

■ Trauma.

■ Failed autogenous or alloplastic TMJ reconstruction.

■ Heterotopic bone and ankylosis.

■ Congenital deformation or absence of the TMJ.

■ Tumors.

■ Connective tissue and autoimmune diseases.

■ Other end-stage TMJ pathologies. Some of the disorders (e.g., congenital deformation or absence of the TMJ) may have the best outcome with a custom-fitted total joint prosthesis, while other disorders (e.g., trauma) very much benefit from a stock prosthesis system that can be inventoried and available for immediate use. Surgeon experience and preference, patient urgency and cost may dictate the risk versus benefit ratio of ordering a custom device that can take several months to design and manufacture versus using an off-theshelf device that will fit most mandibles with minor to moderate modification of the bone. The surgical techniques differ slightly, and the experienced TMJ surgeon should feel comfortable using either prosthesis depending on the clinical situation. As in any surgery, TJR surgery has complications, but modern techniques (such as virtual surgical planning), strict attention to infection control principles, a thorough understanding of the prosthesis design and an intimate knowledge of the surgical anatomy significantly lowers the risk of complication.

Although this section is focused on prosthetic reconstruction of the TMJ, it is important to understand that TMJ reconstruction in children utilizes the costochondral graft, which is considered to be the most acceptable TMJ-replacement tissue for the growing child. The rib is harvested from the child and trimmed to the length needed; the end of the rib is hand carved to fit the fossa while maintaining some of the natural cartilage cap that is present on the end of the rib. The rib is then adapted to the lateral aspect of the mandibular ramus and fixated with several screws. There is a “grow-as-yougo” potential to costochondral grafts, although growth of the operated side is unpredictable, as it is possible for the rib to overgrow or ankylose, resulting in the need for additional surgery. Long-term studies reviewing the fate of the costochondral graft showed that only 38% of the patients had growth equal to the opposite side. [9–13] For patients with high-grade inflammatory disease at the TMJ, implantation of autogenous bone is subject to resorption, leading to instability of the occlusion and the need for repeat surgery. As a result, the alloplastic TMJ prosthesis is recommended for patients who are skeletally mature. The advantages of a prosthetic joint replacement include no need for donor-site surgery, the ability to begin physical therapy quickly, shorter operating time and no relapse potential, especially when TJR is combined with orthognathic surgery. There is no doubt that the solid vertical strut provided by a prosthetic joint can outperform natural tissue in many ways. The following two cases illustrate the utility of the stock joint prosthesis and the custom joint prosthesis.

Case 1

A 70-year-old man with bilateral mandible fractures underwent open repair of displaced left condylar fracture ( FIGURE 4A). Fracture of the bone plate noted three weeks postoperatively, characterized by joint pain and sudden change in occlusion ( FIGURE 4B). Posteroanterior cephalometric view demonstrates the fractured plate (arrow, FIGURE 4C). Due to difficulty of effecting a stable repair, a decision was made intraoperatively to remove the traumatized condyle and coronoid process and immediately reconstruct with a stock TMJ prosthesis ( FIGURE 4D). The polyethylene fossa is radiolucent, but the screws are visible.

Case 2

A 64-year-old man presented with a fractured reconstruction plate that had a previous repair ( FIGURE 5A). The original reconstruction plate was placed after a resection for oral squamous cell carcinoma, followed by adjuvant chemotherapy and radiation treatment. A 3D virtual model demonstrates the fracture and collapse of the reconstruction plate and malposition of the condylar head ( FIGURE 5B). The 3D reconstruction is used to generate a 3D model ( FIGURE 5C) where further resection is done and a wax mock-up of the prosthesis is made, including the fossa/eminence and a separate, extended condylar/ramus/body/symphyseal component. The completed prosthesis including the fossa/eminence prosthesis made up of high molecular weight plastic fused to an underlying titanium mesh and the extended condyle/ramus prosthesis made of a chromium/cobalt alloy ( FIGURE 5D). Resection of the native condyle and articular disc is completed ( FIGURE 5E). The prosthetic fossa/eminence prosthesis is secured in place with screws ( FIGURE 5F). The condylar/ramus extended unit is placed ( FIGURE 5G); the photograph demonstrates the articulation between the new condyle and the new fossa/eminence. The extended condyle/ramus prosthesis is secured to the distal mandible in the symphyseal region ( FIGURE 5H). Postoperative panoramic radiograph demonstrates the new prosthesis in place ( FIGURE 5I). Postoperative posteroanterior radiograph demonstrates the acceptable symmetry achieved with the new TMJ prosthesis in position (TMJ Concepts, Ventura Calif.) ( FIGURE 5J).

Splint Therapy

The role of splint therapy in the management of TMJ disorders has a long history for the treatment of the constellation of symptoms surrounding TMD as well as aiding in the treatment of post-surgical discomfort. The use of splints in the management of myofascial pain seems to be relatively well understood by the population of dentists, generalist and specialist alike. How these appliances are used and by whom have a wide variation. For patients who appear to be grinding their teeth without symptoms, it is common for the general dentist to prescribe a nightguard. This may be made of a soft silicone-based material or hard acrylic. The desired goal is to protect the teeth from further wear. Patients tend to wear them when they sleep, and both types of devices usually serve the purpose for which they were prescribed. In some cases, unanticipated consequences of these devices are observed. With soft splints, some patients end up clenching more and use them as a “chew toy,” developing soreness in their teeth or jaw muscles. With hard splints, patients sometimes complain of subtle changes to their bite, usually occurring if they wear these appliances more than just at nighttime. Even with just sleep time wear, patients will usually awake with a subtle change in their occlusion simply because they have not been touching their teeth together during the night, and they temporarily lose their proprioceptive input. [14] For the post- TMJ surgery patient, however, a hard occlusal splint will help unload the joint during the healing phase and contribute to postoperative pain management. Excessive forces placed upon the newly operated joint from bruxism are reduced with splint therapy, which helps to decrease local postoperative edema and inflammation within the joint complex.

Many surgical and nonsurgical patients with a great deal of parafunction during the night and occasionally during the day often develop episodic pain in the TMJs and in the temporalis and masseter muscles as well as the posterior cervical and occipital muscles, leading to significant headache problems. A well-designed splint can decrease symptoms by as much as 100% but requires specific follow-up management. This includes equilibration of the splint and evaluation of muscle pain with muscle palpation tests designed to elicit the amount of pain the patient is experiencing, correlating it with the amount of bruxism and/or clenching evident on the orthotic. A good bit of counseling as well as use of other modes of treatment, including anti-inflammatory medications, muscle relaxants, botulinum toxin injections and sometimes physical therapy, all help the patient to manage this problem effectively. Discussion of proper ergonomics at work, the relationship of stress to these parafunctional habits, the role of proper sleep hygiene as well as an evaluation of the possibility of sleep apnea can assist in the successful management of these problems. [15]

Patients may present with all of the above-mentioned problems in addition to clicking or popping of one type or another. As mentioned in the Wilkes classification system, there can be a progression of signs and symptoms that indicate more intracapsular problems within the joint. A very early internal derangement, such as anterior disc displacement, might be solved by using a splint to recapture the disc and continuing to take the stress off the TMJ utilizing a splint of a somewhat different design. The use of splints for these purposes, however, is beyond the scope of this article.

The study of occlusion is of paramount importance to our daily dental practice. There are different philosophies about the relationship between occlusion and the TMJ. To be sure, the TMJ is not only the most complex joint of the body, but it is also arguably the most adaptable joint in the body. This is both a good and potentially perplexing aspect about the function of this joint. There is a lot of controversy regarding the relationship between occlusion and potential TMJ pathologies. Intracapsular problems relating to the articular disc and degenerative joint conditions can definitely alter the dental occlusion, but current research seems to indicate that malocclusion does not cause TMJ dysfunction and joint pathology. This is a concept that many dentists find difficult to accept. It is very challenging to study TMJ pathology in a randomized, placebocontrolled fashion. Thus, we are left with many studies of small sample size that are studied with highpowered meta-analyses to attempt to reach a statistically significant sample size and then isolate different components of the study groups and draw meaningful conclusions.

Many orthodontists see a strong correlation between class II, division 2 malocclusions with retroclined central incisors and an anterior deep bite and distal displacement of the condyles within the glenoid fossa. This altered condylar position is often accompanied by anterior disc displacement. If a diagnostic splint is given to the patient that removes the effects of the anterior deep bite and the patient wears this full time, it is common to see the condyle reposition to a normally centered place within the glenoid fossa. It is equally common to see the disc and condyle assume a normal relationship, resulting in a diminishing of the clicking that was present before splint therapy, unless there has been significant damage to the ligaments or articular disc. Similarly, with other malocclusions to which the patient has accommodated, the placement of a full-time repositioning splint would allow the condylar position to change from abnormal to a normally centered position. Treatment sometimes uncovers a significantly different occlusion than the patient had to begin with. While disconcerting, this finding allows the practitioner the ability to treat the true anatomic problem, having a much more successful treatment outcome for the health of the dentition, periodontal structures and temporomandibular joints.

Treatment sometimes uncovers a significantly different occlusion than the patient had to begin with.

In patients who present with TMJ dysfunction, a period of management with diagnostic and/or treatmentoriented splint therapy would help improve condylar position and create an environment for the surgical repositioning of an anteriorly displaced disc whether it is done via arthroscopic or open joint surgery. Post-surgical stabilization with splint therapy would give the patient an artificial, ideal, good bite with which to function while healing. The underlying malocclusion may still exist and need to be treated, but the ill effects of it would be controlled by the stability of the splint, thus allowing favorable healing. The combination of pre- and post-surgical splint therapy would allow for the most physiologic joint positioning for any of the surgical procedures mentioned previously. This of course would exclude trauma cases or any case that requires immediate surgery with joint replacement, without the benefit of the time to preplan the entire sequence of treatment. The use of a post-surgical splint in just about every case would allow for healing to take place with reduced load on the joint and better function for the patient during recuperation, thus allowing for preparation of the final restoration of the occlusion.

Discussion

Oral and maxillofacial surgeons who make temporomandibular surgery a consistent part of their clinical practice serve the public by being subspecialists in a challenging and evolving field. Not only must surgical skills be at the highest level, but the surgeon must be an excellent diagnostician and be adept at sorting through a variety of nonsurgical diagnostic and therapeutic interventions to manage patients pre- and postoperatively. A close working relationship with an orthodontist focused on splint therapy both before and after disc surgery can result in improved outcomes through the precise control of condylar position and a decrease in the load experienced by the joint complex.

In many clinical situations, the TMD treatment pyramid has been turned upside down, with surgery-first options allowing for precise correction of skeletal and functional problems that permit the secondary dental rehabilitation procedures to move forward. Surgical correction of articular disc disorders has advanced significantly with the recognition that bone-against-bone articulation within the fossa yields results prone to dramatic remodeling and malocclusion. Articular disc replacement using a variety of autogenous and alloplastic tissue brings much-needed outcome consistency to our patients. Replacement of the entire TMJ complex is complicated, and material science and innovation in prosthesis design will be the next steps forward. Already, virtual surgical planning in the computational 3D environment has given surgeons confidence in the anticipated surgical outcomes. This is particularly true for patients with the dual diagnosis of TMD and skeletofacial deformities that require careful presurgical orthodontic preparation. The idealized condylar position, which often alters the occlusion, can be captured on a high-resolution CT scan and duplicated during surgery through the use of CAD/CAM splint fabrication once the surgical plan has been developed through virtual surgical planning.

The future of TMJ surgery may lie in the incorporation of patient-specific TMJ replacement or TMJ articular resurfacing with grafts that are both bioengineered and stem cell based. Outstanding research over the past decade has shown surgeons the future of TMJ bioengineering. The horizon has been broadened, and our patients will benefit from current state-ofthe-art and future innovations.

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THE CORRESPONDING AUTHOR, Rebeka G. Silva, DMD, can be reached at drsilva@diossf.com.