The condylar capping for microvascular temporomandibular joint reconstruction: A preliminary study.

BACKGROUND: Defects of the temporomandibular joint (TMJ) are often difficult to be reconstructed in the correct dimensions and function. This preliminary study aims to describe a novel technique of condylar reconstruction with a microvascular flap in case of deforming arthrosis of the TMJ: condylar capping. PATIENTS AND METHODS: Four patients between 22 and 62 years old-three females and one male-with severe unilateral arthrosis of the TMJ underwent condylar capping. All patients had already had a failed conservative treatment, followed by arthroscopy with lysis and lavage and later open surgery with total or subtotal diskectomy combined with a condylar arthroplasty. Nevertheless, their pain was still at level six or more on a visual analogue scale. Moreover, they could eat only soft food. At this stage, they underwent condylar capping using an osteochondral lateral femoral condyle (LFC) flap. The surgical technique and the postoperative management are described in detail. Crucially the attachment of the lateral pterygoid muscle to the condylar neck was preserved in all cases. The patients were followed up clinically and by CT scan preoperatively, 6, and 12 months postoperatively. RESULTS: The mean height of the reconstructed neo-condyle was 6.0 mm, the mean width 16.2 mm, and the mean sagittal length 9.8 mm. The follow-up period ranged from 14 to 64 months. The procedures were uneventful for all patients, and the donor site morbidity was negligible. Twelve months later, the patients were all pain-free and able to have a regular diet. The TMJ and the knee had a normal range of movement and power. Postoperative imaging demonstrated bone healing and stable and anatomically correct condyle reconstruction. CONCLUSIONS: Based on the author's experience, the condylar capping with the LFC appears promising for reconstructing the condylar head in cases of severe osteoarthritis. Preserving the attachment of the lateral pterygoid muscle allows a complete restoration of the physiologic range of movement, including protrusion and laterotrusion of the mandible.

Influence of different treatment procedures on the temporomandibular joint after mandibular setback in skeletal class III - A retrospective study.

The aim of this study was to clarify the effects of three different orthognathic surgical procedures on the temporomandibular joint after mandibular setback. Conventional sagittal split ramus osteotomy (SSRO) with segmental fixation (conv-SSRO), intraoral vertical ramus osteotomy (IVRO), or SSRO without fixation followed by the physiological positioning strategy (nonfix-SSRO) was performed for mandibular setback. Temporomandibular joint disorder (TMD) symptoms were clinically assessed, and the condylar head angle was measured. In total, 129 patients participated. Preoperative TMD and treatment procedure were related to postoperative TMD. A menton deviation of 3.43 mm was the cutoff for the risk of postoperative TMD. The incidence rate of postoperative TMD in the conv-SSRO group was higher than that in the IVRO (p = 0.0197) and nonfix-SSRO (p = 0.0001) groups in asymmetric cases. There was no significant postoperative change in the temporomandibular joint space in each group. In symmetric and asymmetric cases, the condylar head was rotated inwards by 5.82 ± 4.75° (p < 0.0001) and 5.44 ± 3.10° (p < 0.0001), respectively, in the conv-SSRO group, and outwards by -7.98 ± 5.05° (p < 0.0001) and -8.32 ± 6.38° (p < 0.0001), respectively, in the IVRO group, but it was almost stable in the nonfix-SSRO group. Within the limitations of the study it seems that nonfix-SSRO should be preferred over conv-SSRO and IVRO whenever appropriate.

Características anatómicas-funcionales que orientan la posición del cóndilo en la fosa mandibular en una relación céntrica: una descripción narrativa / Anatomical functional characteristics that guide the condylar position in mandibular fossa a centric relation: narrative description

RESUMEN: La Relación Céntrica (RC) es un concepto que busca definir la posición ideal del cóndilo de la mandíbula en la fosa mandibular, siendo esta posición muy discutida en la literatura y ha ido cambiado con los avances en conocimiento y tecnología. Tomándose en la actualidad en consideración elementos anatómicos esenciales que son utilizados como guía para el clínico. La importancia de poder reconocer esta posición radica en la correcta ejecución tanto de procedimientos diagnósticos como de tratamiento en diversas áreas de la odontología. Existen elementos anatómicos de la articulación temporomandibular (ATM) que nos ayudarían a comprender mejor el concepto de RC, entre estos destacan que la condensación ósea de las superficies articulares funcionales y su recubrimiento por fibrocartílago; la porción media del disco articular, desprovista de vasos y nervios; el techo de la fosa mandibular que puede llegar a ser extremadamente delgado por lo cual no se consideraría un área para soportar carga; la prolongación posterior del disco articular (DA) que es altamente vascularizada e inervada. El DA se encuentra íntimamente relacionado con estructuras como el ligamento temporomandibular o lateral y la cabeza superior del músculo pterigoideo lateral que permitirían junto a los elementos anteriormente mencionados el adecuado funcionamiento de la ATM. El correcto aprendizaje y utilización de estos conceptos contribuirá a lograr un mejor ejercicio del desarrollo profesional de estudiantes y profesionales del área de la odontología.

SUMMARY: The Central Relation (CR) is a concept that defines the ideal position of the mandibular condyle in the mandibular fossa. The position has been the subject of much discussion in the literature, noting changes as advancements in knowledge and technology are achieved. Thus, certain essential anatomical elements that are used as a guide for the clinician, are taken into account. The importance of being able to identify this position lies in the correct execution of both diagnostic and treatment procedures in various areas of dentistry. There are anatomical elements of the temporomandibular joint (TMJ) that improve understanding of the CR concept. These include: Bone condensation of the functional articular surfaces and their fibrocartilage coating; the middle portion of the joint disc, devoid of vessels and nerves. The roof of the mandibular fossa can become extremely thin, so it would not be considered an area to support load; the posterior prolongation of the articular disc (AD) Which is highly vascularized and innervated. The AD is also closely related to structures such as the temporomandibular or lateral ligament and the superior head of the lateral pterygoid muscle. Along with the previously described elements, this would allow proper functioning of the TMJ. The correct learning and use of these concepts contributes to a better exercise in the professional development of students and professionals in the area of dentistry.

On the reinsertion of the lateral pterygoid tendon in total temporomandibular joint replacement surgery.

This report aims to present the concept of reestablishing lateral pterygoid muscle function during total temporomandibular joint (TMJ) replacement surgery. The key feature is a lattice structure (scaffold) located in the condylar neck of a titanium, three-dimensionally (3D)-printed mandibular component that houses morselized autologous bone from the resected condyle and osteogenic stem cells from iliac bone marrow aspirate, and to which the fibrous enthesis component (collagen attachments to a bone fragment) is fixed via suture cerclage prior to the development of the bony union. Five TMJs were replaced using enthesis reconstruction in three patients who were followed for 1 year and more. Laterotrusion to the contralateral side measured on average 6.4 mm preoperatively, 2.3 mm at 1 month, 3 mm at 3 months, 4 mm at 6 months, and at 1-1.5 years (62,5% of the preoperative laterotrusion/40% of a normal laterotrusion). Subjective normalization of mastication after 1 year was present in all patients. A successful reattachment of the enthesis to an alloplastic endoprosthesis suggests that patients will not only be able to open and close their mouths properly with reduced pain but will also be able to actually chew. The technique has potential applications in orthopedic alloplastic reconstruction.

The different effects of intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO) on mandibular border movement.

OBJECTIVES: This study investigated the different effects of intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO) on mandibular border movement. METHODS: The participants included 22 patients receiving IVRO and 22 patients receiving SSRO who were treated at Okayama University Hospital. Their mandibular border movement was evaluated in three dimensions with 6° of freedom using an optical recording system. RESULTS: A strong correlation between condylar and lower incisor movement was observed during maximum jaw protrusion and laterotrusion. Significant improvements in condylar and lower incisor movement were detected after orthognathic surgery during maximum jaw protrusion and laterotrusion in the IVRO group and during maximum jaw protrusion in the SSRO group. DISCUSSION: IVRO likely achieves greater improvement in jaw movement than SSRO. Therefore, the application of IVRO could be considered in the treatment of patients with jaw deformities featuring temporomandibular joint problems.

Physiological positioning strategy alters condylar position after mandibular ramus sagittal split osteotomies for mandibular prognathism.

OBJECTIVE: The aim of this study was to elucidate the physiological position of the proximal segment for postoperative jaw movement in patients with mandibular prognathism. METHODS: Twenty-two patients with mandibular prognathism were treated by orthognathic surgery using bilateral mandibular sagittal split ramus osteotomies (SSRO) with a physiological positioning strategy. The skeletal stability was assessed, and the movement of the proximal segment was evaluated by cephalography and computed tomography performed preoperatively, immediately postoperatively, and one year postoperatively. RESULTS: The patients were divided into two groups: the stable group (SNB relapse <1.5°) and the relapse group (SNB relapse ≥1.5°). In the stable group at one year postoperatively, the average SNB relapse was only 0.29° (7%), the condylar head had moved posteriorly by 0.75 mm, and the proximal segment had rotated counterclockwise by 1.2°. CONCLUSION: This new physiological positioning strategy improves the position of the condyle compared with the preoperative position in patients with mandibular prognathism.

Curva de Spee: causas y tratamiento de su descompensación / Spee curve: causes and treatment of its discompensation

En el presente artículo se analiza y pasa revista a la bibliográfica acerca de la Curva de Spee: su etiología, los diferentes factores que pueden descompensarla, y los posibles tratamientos para corregirla en caso deestar alterada. Una mordida abierta esqueletal o dentaria, o una mordida profunda esqueletal o dentaria pueden modificarla, pudiendo utilizarse varios recursos y técnicas para tratar estos desórdenes, y así nivelar la curva.

In the present paper, the literature is analysed and reviewed the Curve of Spee: its aetiology, the different factors that can decompensate it, and the possible treatments to correct it in case of beingaltered. An open skeletal or dental bite, or a deep skeletal ordental bite can modify it, being able to use several resources and techniques to treat these disorders, and thus to level the curve.

Axial four-dimensional computed tomographic images to analyze crosswise differences in protrusive condylar movement in patients who underwent mandibulectomy and free flap reconstruction.

OBJECTIVE: Few studies evaluate condylar movement following mandibular reconstruction. The main objective of this study was to show that axial four-dimensional computed tomography (4DCT) could visualize bilateral protrusive condylar movement directly. We used axial 4DCT images to assess condylar protrusion in patients who underwent mandibular reconstruction. METHODS: We enrolled seven healthy volunteers (median age 30 years, range 27-38 years) and seven patients (median age 65 years, range 52-80 years), who underwent mandibulectomy (segmental in five, hemi in one, marginal in one) and free flap reconstruction (using the fibula in six and the radial forearm in one). Six study subjects were instructed to masticate a cookie during the 4DCT scan (the seventh made chewing motions). The distance between the most anterior and posterior positions of the bilateral condyles on 4DCT (axial view) images was then measured and compared between controls and patients using the Mann-Whitney U-test. RESULTS: The crosswise difference in the distances of condylar protrusion was significantly greater in patients than in the controls. CONCLUSION: Axial 4DCT images can visualize a bilateral condylar protrusive path. Axial 4DCT images for patients who have undergone mandibulectomy and reconstruction may be useful for evaluation of functional movement of condyles.

Three-dimensional analysis of condylar remodeling and skeletal relapse following bimaxillary surgery: A 2-year follow-up study.

PURPOSE: To quantify the postoperative condylar remodelling and its role in skeletal relapse after bimaxillary surgery. MATERIALS AND METHODS: 50 patients with mandibular hypoplasia who underwent bimaxillary surgery were analyzed. CBCT scans were acquired preoperatively, one week postoperatively and two years postoperatively. 3D cephalometric analysis was carried out for each CBCT scan, after which the condylar volume analysis was performed. RESULTS: The maxilla was advanced by a mean of 2.1 mm with a corresponding mean relapse of 0.3 mm. The maxilla was impacted in 23 and extruded in 27 patients. The mean mandibular advancement was 7.8 mm. Two years after surgery a mean mandibular skeletal relapse of 1.3 mm was observed. 78% of condyles exhibited a postoperative reduction in volume of 179 mm3 (mean), equivalent to 12.5 volume%. Postoperative condylar volume loss was correlated with mandibular skeletal relapse (r = 0.42, p < 0.01), but not with maxilla relapse. Linear regression analysis identified age, gender, amount of surgical mandibular advancement and postoperative condylar volume loss as predictive factors for mandibular relapse. CONCLUSION: A significant correlation between postoperative condylar volume loss and skeletal relapse was found. Young female patients who underwent large bimaxillary advancement and postoperative reduction in condylar volume were particularly at risk for skeletal relapse.

Neocondylar formation after resection of the mandible and reconstruction with a vascularised iliac crest free flap: rare case.

Tumours in the mandible often necessitate the removal of both mandibular and condylar bone. A free vascularised bone flap is a common choice for reconstruction, but it is rare for adults to form a new condyle after it. We describe a patient in whom a new condyle did form after reconstruction with a vascularised iliac crest free flap.

Can Mandibular Condylar Mobility Sonography Measurements Predict Difficult Laryngoscopy?

BACKGROUND: Limited mandibular condylar mobility plays an important role in difficult laryngoscopy. Indirect assessment methods, such as mouth opening, have been proven to be useful predictors of difficult laryngoscopy. Sonography is a new direct assessment method for the limited mandibular condylar mobility. However, whether this method could be used in predicting difficult laryngoscopy still remains unknown. This study aimed to observe its ability to predict difficult laryngoscopy. METHODS: Adult patients who were administered tracheal intubations for elective surgery under general anesthesia were enrolled in the study. Mandibular condylar mobility was assessed by sonography through condylar translation measurements. Beside mouth opening, other indirect variables that correlated with temporomandibular joint mobility, such as mandibular protrusion distance, upper lip bite test, and whether the condyle-tragus distance was <1 finger breadth, were also evaluated before anesthesia. The primary outcome was difficult laryngoscopy defined as the Cormack-Lehane level 3 or 4. RESULTS: A total of 484 patients were prospectively included, and difficult laryngoscopy was reported in 41 patients. The condylar translation prediction criterion for difficult laryngoscopy was ≤10 mm. The condylar translation was correlated with Cormack-Lehane level (Spearman correlation coefficient, -0.46; 99% confidence interval [CI], -0.55 to -0.36) and owned the highest area under the receiver operating characteristic curve (0.93; 99% CI, 0.90 to 0.96, compared with that of the other predictors, P < .001) with difficult laryngoscopy. The condylar translation ≤10 mm was with a considerable κ value (κ = 0.52; 99% CI, 0.37 to 0.67) to difficult laryngoscopy and proved to be an independent predictor by a multivariate logistic regression. CONCLUSIONS: Compared with indirect assessments, such as mouth opening and other parameters, mandibular condylar mobility, as assessed directly using sonography, was correlated with difficult laryngoscopy and demonstrated an independent and notably predictive property.

Activation of α2A-adrenergic signal transduction in chondrocytes promotes degenerative remodelling of temporomandibular joint.

This study tested whether activation of adrenoreceptors in chondrocytes has roles in degenerative remodelling of temporomandibular joint (TMJ) and to determine associated mechanisms. Unilateral anterior crossbite (UAC) was established to induce TMJ degeneration in rats. Saline vehicle, α2- and ß-adrenoreceptor antagonists or agonists were injected locally into the TMJ area of UAC rats. Cartilage degeneration, subchondral bone microarchitecture and the expression of adrenoreceptors, aggrecans, matrix metalloproteinases (MMPs) and RANKL by chondrocytes were evaluated. Chondrocytes were stimulated by norepinephrine to investigate signal transduction of adrenoreceptors. Increased α2A-adrenoreceptor expression was observed in condylar cartilage of UAC rats, together with cartilage degeneration and subchondral bone loss. Norepinephrine depresses aggrecans expression but stimulates MMP-3, MMP-13 and RANKL production by chondrocytes through ERK1/2 and PKA pathway; these effects were abolished by an α2A-adrenoreceptor antagonist. Furthermore, inhibition of α2A-adrenoreceptor attenuated degenerative remodelling in the condylar cartilage and subchondral bone, as revealed by increased cartilage thickness, proteoglycans and aggrecan expression, and decreased MMP-3, MMP-13 and RANKL expressions in cartilage, increased BMD, BV/TV, and decreased Tb.Sp in subchondral bone. Conversely, activation of α2A-adrenoreceptor intensified aforementioned degenerative changes in UAC rats. It is concluded that activation of α2A-adrenergic signal in chondrocytes promotes TMJ degenerative remodelling by chondrocyte-mediated pro-catabolic activities.

Effects of mandibular advancement surgery on the temporomandibular joint and muscular and articular adaptive changes--a systematic review.

The objective of this study was to assess the anatomical changes to the condyle and articular disc following mandibular advancement surgery, the adaptation of the masticatory muscles, and the improvement or worsening of temporomandibular disorders (TMD) in patients with pre-existing disorders and those who developed them following surgery. Four databases were searched systematically: PubMed, Scopus, Embase, and Cochrane Library. Of the 544 articles initially selected, 219 were duplicates and a further 165 were excluded on the basis of their titles and abstracts. On reading the full text, 89 were excluded because they were of no interest and 43 because they did not meet the inclusion criteria. Of the remaining 28 articles, six were excluded because they were considered of low quality and 22 articles were reviewed. Mandibular advancement surgery with condyle repositioning is associated with less TMD. Condylar resorption is a physiological process with a multifactorial aetiology. It is accelerated following mandibular advancement surgery but is not a contraindication to this procedure. Despite the large number of studies on the effects of mandibular advancement surgery on the temporomandibular joint (TMJ), this surgery can neither be said to improve nor to worsen TMJ health.

Three-dimensional analysis of postoperative returning movement of perioperative condylar displacement after bilateral sagittal split ramus osteotomy for mandibular setback with different fixation methods.

This study aimed to evaluate postoperative returning movement of perioperative condylar displacement after bilateral sagittal split ramus osteotomy (BSSRO) depending on a fixation method using three-dimensional (3D) analysis of computed tomography (CT). Twenty-five mandibular prognathic patients (50 condyles) who underwent orthognathic surgery with BSSRO were divided into three groups depending on the fixation method, which consisted of miniplate only (Group A), combined with single bicortical screw (Group B), or with more than one bicortical screw (Group C). CT data taken before, immediately after, and 3 to 6 months after surgery were analyzed. The condyle exhibited mainly lateral bodily displacement and inward and inferior rotation immediately after surgery. The amount of perioperative lateral displacement of the condyle increased according to the increasing number of fixation screws, but the mean displacements were not significantly different among the three groups. During the postoperative follow-up period, the amount of medial returning of the condyle was 102.2% of the intraoperative lateral displacement in Group A. In contrast, Group B and C exhibited partial returning movement by 71.3% and 38.9% of cases, respectively. In conclusion, stronger rigid internal fixation in orthognathic surgery using BSSRO is associated with reduced flexibility of postoperative functional adjustment of displaced condyle to the preoperative condylar position.

The role of mandibular proximal segment rotations on skeletal relapse and condylar remodelling following bilateral sagittal split advancement osteotomies.

PURPOSE: To quantify the postoperative rotation of the proximal segments in 3D and to assess its role on skeletal relapse and condylar remodelling following BSSO advancement surgery. MATERIAL AND METHODS: 56 patients with mandibular hypoplasia who underwent BSSO advancement surgery were enrolled into the study. A CBCT scan was acquired preoperatively, at one week postoperatively and at one year postoperatively. After segmentation of the facial skeleton and condyles, 3D cephalometry and condylar volume analysis were performed. RESULTS: A mean mandibular advancement of 4.6 mm was found. 55% of the condyles decreased in volume postoperatively, with a mean reduction of 6.1 volume-percent. Among 11 patients who exhibited a clinically significant relapse of more than 2 mm, 10 patients exhibited a counterclockwise rotation of the proximal segments. The odds of skeletal relapse (>2 mm) was 4.8 times higher in patients whose proximal segments were rotated in a counterclockwise direction. Postoperative flaring (3.3 mm) and torque (0.3°) were, however, not associated with skeletal relapse or condylar remodelling. CONCLUSION: Gender, preoperative condylar volume, postoperative condylar remodelling, counterclockwise rotation of the proximal segment and the amount of surgical advancement were prognostic factors for skeletal relapse (r(2) = 0.83). The role of the mandibular plane angle in relapse is questionable.

Christensen vs Biomet Microfixation alloplastic TMJ implant: Are there improvements? A numerical study.

The objective of this study was to compare the load transfer mechanism and behavior of two total temporomandibular joint (TMJ) prostheses: Biomet and Christensen TMJ models were simulated. Computed tomography (CT) images from a specific patient were used to generate two models for use in simulation of implantation for the total temporomandibular prostheses. Three finite element models were created in all. One considered the intact temporomandibular joint and two received a temporomandibular implant. In the simulation we considered the five most important muscles acting on the mandible and incisor teeth support. The Christensen model reduced strain in the opposite condyle by around 50% while increasing strain in the implanted condyle. The changes in the posterior side of the implanted condyle present an increase of five times the minimum principal strain, suggesting some bone fatigue. With the Biomet implant, the reduction in strain in the implanted condyle on the posterior side was around 100%, suggesting the possibility of some bone loss proximally near the resection plane. Based on our results, we conclude that in both models the implants influence the behavior of the mandible by improving the symmetry of the mandible and strain distribution. The Biomet implant modifies the behavior of the mandible slightly and presents some improvements over the Christensen TMJ model in strain distribution and tensions in the opposite intact disc similar to the non-implanted situation.

The stock alloplastic temporomandibular joint implant can influence the behavior of the opposite native joint: A numerical study.

PURPOSE: The objective of the study was to investigate the effect of total stock temporomandibular implants on load mechanisms in both condyles in a specific patient. The patient presented with a disc with wear, and the introduction of a total temporomandibular prosthesis was simulated to compare the articular behavior. MATERIAL AND METHODS: Based on specific patient computed tomographic images, two finite element models were created: one model with two intact temporomandibular joints (one joint with pathology), and other model with one implanted joint. The simulations considered the five most important muscles acting in the mandible, and it was possible to evaluate the biomechanical changes in the structures (skull, mandible, and articular disc). RESULTS: The results revealed more load transfer in the opposite condyle than in the damaged one; the insertion of a total temporomandibular implant changed the load transfer to the opposite condyle. There was decreased stress in the disc by about 50% and increased strain distribution. In the mandibular condyle with implant, the screw fixation is critical, with minimum strain around -9430 µÎµ for first screw position. In the cranium, the implant changed the bone strains with a minimum principal strain observed around -2500 µÎµ in six screw positions. CONCLUSION: This study indicates that replacing the damaged joint by an implant in an ideal position will improve joint position and consequently redistribute the loads. The study findings provide strong evidence that placing an implant on one side of the mandible will affect the load distribution on that structure and particularly on the opposite side. The temporomandibular joint changes condyle movement; with an implanted condyle, the movement is almost blocked.

[Condylar remodelling after temporomandibular joint reconstruction with fibula free flap]. / Remodelage du condyle après reconstruction de l'articulation temporomandibulaire par lambeau libre de fibula.

AIM: Mandibular reconstructions with fibula free flap are commonly used in maxillo-facial surgery; termino-lateral mandibulectomy with reconstruction of the ramus and condylar unit is seldom used. Consequences on the temporomandibular joint remain unclear, and the type of reconstruction is still subject to controversy. METHODS: Six patients were followed after terminal mandibulectomy, reconstructed with fibular free flap. Evaluations of the results were made on functional and radiological criteria. RESULTS: No patient presented functional disturbances due to reconstruction. Remodeling of the neocondyle extremity was weak in adults but important in children, with modification of morphology and architecture of the condyle in children. DISCUSSION: Preservation of the disc is recommended. Many techniques are described to improve congruence, preservation and remodeling of the free extremity of the fibula flap. All give similar results. It seems that the real determinant factors on the quality of the result are age, presence of the disc or not, previous surgery performed, with or without radiotherapy.

Prosthesis loading after temporomandibular joint replacement surgery: a musculoskeletal modeling study.

One of the most widely reported complications associated with temporomandibular joint (TMJ) prosthetic total joint replacement (TJR) surgery is condylar component screw loosening and instability. The objective of this study was to develop a musculoskeletal model of the human jaw to assess the influence of prosthetic condylar component orientation and screw placement on condylar component loading during mastication. A three-dimensional model of the jaw comprising the maxilla, mandible, masticatory muscles, articular cartilage, and articular disks was developed. Simulations of mastication and a maximum force bite were performed for the natural TMJ and the TMJ after prosthetic TJR surgery, including cases for mastication where the condylar component was rotated anteriorly by 0 deg, 5 deg, 10 deg, and 15 deg. Three clinically significant screw configurations were investigated: a complete, posterior, and minimal-posterior screw (MPS) configuration. Increases in condylar anterior rotation led to an increase in prosthetic condylar component contact stresses and substantial increases in condylar component screw stresses. The use of more screws in condylar fixation reduced screw stress magnitudes and maximum condylar component stresses. Screws placed superiorly experienced higher stresses than those of all other condylar fixation screws. The results of the present study have important implication for the way in which prosthetic components are placed during TMJ prosthetic TJR surgery.