Adolescent female craniofacial morphology associated with advanced bilateral TMJ disc displacement

The aim of this study was to determine if cephalometric measurement differences occurred between two groups of similarly aged female adolescents which differed with respect to their diagnoses of temporomandibular joint disc position on magnetic resonance images (MRI). One group consisted of 17 female adolescents exhibiting complete bilateral disc displacement affecting the temporomandibular joints (TMJ), while the second group of 17 female adolescents was diagnosed as having bilateral normal disc position on MRI. Independent sample t-tests identified statistically significant differences in cephalometric measurements between the two groups, but no age difference between the two groups was evident. The group with bilateral total disc displacement exhibited the following significant angular differences from the group with normal disc position: an increased mandibular and palatal plane relative to sella-nasion; posterior rotation of the mandible as illustrated by an increased angle between the posterior border of the mandibular ramus and sella-nasion; and a decrease in Rickett's facial axis. Significant differences in linear cephalometric variables were also evident between the two groups. Total posterior facial height and ramus height were reduced in the totally disc displaced group. Furthermore, a slight increase in the middle anterior facial height was noted, with a decrease in the posterior cranial base vertical height in the totally disc displaced group.     

Surgical treatment of ankyloses of the temporomandibular joint in children

Ankylosis of the temporomandibular joint leads in children to serious disorders such as loss of dentition, growth retardation of the lower jaw, facial asymmetry etc. During the period from 1993 till 1997 we treated 12 children incl. eight who had unilateral and four bilateral ankylosis. In six patients, after elimination of the ankylosis, reconstruction of the head was made with a total of nine costochondral grafts. In entire all patients the temporal muscle or a silicone plate was interposed between the skull base and mandible. Postoperative complications were minimal. Surgical treatment, which is only half of the issue of treatment, must be followed by long-term careful rehabilitation. The results which were achieved contributed in a significant way to a more favourable further development of the children.     

Position of the mental foramen in adult black Zimbabwean mandibles: a clinical anatomical study

OBJECTIVE: To provide some anatomical information on the shape, size, and position of the mental foramen among Black Zimbabweans that could be used as reference material by dental and other health practitioners during clinical practice in Zimbabwe. DESIGN: Cross sectional anatomical study. SETTING: Department of Anatomy, Faculty of Medicine, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe. SUBJECTS: 32 mandibles derived from adult Black Zimbabweans. MAIN OUTCOME MEASURES: The shape of the mental foramen, its relation to the lower teeth and its position in relation to the mandibular symphysis, the posterior border of the ramus of the mandible, the lower border of the mandible, and the alveolar margin. RESULTS: The shape of the mental foramen was round in 14 out of 32 mandibles (43.8%) and was oval in the remaining 18 (56.3%). The percentage of occurrence of the mental foramen was highest below the lower second premolar tooth on the right side (position 4) and posterior to it on the left side (position 5). In the vertical plane, the mental foramen lay slightly below the midpoint of the distance between the lower border of the mandible and the alveolar margin (44.1% and 45.5% for the right and left sides respectively). In the horizontal plane, it lay approximately one quarter (27.3% for the right and 27.4% for the left sides) of the distance from the mandibular symphysis to the posterior border of the ramus of the mandible. CONCLUSION: The percentage distribution of the mental foremen in relation to the lower teeth in the adult Black Zimbabwean mandible was at variance with that of other population groups. However, the quantitative position of the mental foremen was bilaterally symmetrical in the adult Black Zimbabwean mandible. The latter observation is of clinical significance to dental and other health practitioners in Zimbabwe with regards to the achievement of effective mental nerve block anaesthesia and the prevention of damage to the mental nerve during surgical procedures on the lower jaw.     

Prediction of mandibular autorotation

PURPOSE: The purpose of this investigation was to test the hypothesis that the mandible rotates around the same point during maxillary impaction surgery as during initial jaw opening. This point, called the center of mandibular autorotation (CAR), could then be used to predict mandibular position and to decide whether only maxillary impaction would be needed to correct the occlusion and the facial profile. PATIENTS AND METHODS: Preoperatively, two lateral cephalograms were obtained from a consecutive series of 20 patients who underwent maxillary impaction without concomitant mandibular ramus osteotomy. One cephalogram was taken with the mandible in centric relation using a wax bite wafer and another with a jaw opening of 10 mm using a fabricated acrylic bite block with the mandible manipulated to its most retruded position. The CAR was calculated before and after jaw opening using the Rouleaux method on the lower incisor and gonion point. A third lateral cephalogram was taken within 2 days postoperatively. The postoperative lower incisal point was then transferred to the first cephalogram using cranial base superimposition. RESULTS: When the preoperative and postoperative distances between CAR and incisal point were compared, there was no significant difference between these distances, proving the hypothesis. CONCLUSIONS: The method used is a practical and precise way to determine the center of mandibular autorotation on an individual basis. The center of rotation during initial jaw opening is the same as during impaction surgery.     

Characterization of human p33/41 (annexin IV), a Ca2+ dependent carbohydrate-binding protein with monoclonal anti-annexin IV antibodies, AS11 and AS17

A non-invasive method of assessing the status of the temporomandibular joint is presented. The method involves placing a computer-controlled vibrator against a lower incisor, and microphones over the temporal bones. The amplitude of the signal transmitted is shown to be a function of the input frequency, the position of the mandible and the loading on the joint.     

Effects of primary bone grafting on facial development in patients with unilateral complete cleft lip and palate

The study is based on an anthropometric assessment of X-ray films obtained in 22 adult males with complete unilateral cleft lip and palate treated during childhood with primary bone grafts and in 32 males with the same type of cleft without bone grafting. In the series with bone grafts was recorded a more marked reduction of maxillary depth associated with a larger retrusion than in the series without bone grafts. This deviation was therapeutically compensated by a larger displacement of the mandible backwards which contributes to the increase of mandibular posterior rotation. This provided the possibility to attain an edge to edge bite. Our results confirmed the unfavourable effects of primary bone grafting on maxillary growth and development.     

Disk displacement of the temporomandibular joint: correlation of magnetic resonance tomography and clinical findings

PURPOSE: To evaluate the value of magnetic resonance imaging (MRI) in symptomatic patients with different degrees of internal derangement. MATERIAL AND METHODS: We prospectively investigated 117 temporomandibular joints (TMJ) of 59 symptomatic patients and 31 asymptomatic volunteers and correlated this with clinical parameters. RESULTS: There was a positive correlation between the degree of internal derangement and deformity of the disc, maximal mouth opening, signal intensity of the posterior band, thickness of the bilaminar zone, proliferative bony changes, size of the condyle and reduced translation movement of the condyle, which in addition moved upward and backward. Patients most often complained of pain which was dependent on the degree of disc displacement and condylar changes. Clinical parameters were found to be inaccurate in predicting disc displacement. CONCLUSION: Patients with internal derangement of the temporomandibular joint may be asymptomatic. Patients history may give the only pointer to the disorder.     

Mandibular condyle hyperplasia. Therapeutic review

Excessive cartilage growth on the condyle process of the mandible can result from primary hyperreactivity of the growth cartilage or be a secondary adaptation to an imbalance in occlusive and/or cervicofacial conditions. Treatment depends on the distinction between these two forms. Primary active overgrowth is treated by condylectomy sparing the distal apparatus although conservative surgery to re-centering the temporomandibular joint and re-establish symmetry without condylectomy may be used in quiescent moderately active forms saving the joint. For secondary forms, the joint is re-centering and symmetry is re-established without condylectomy. If started early enough, orthopaedic treatment can avoid the development of secondary forms resulting an imbalance in occlusive and/or cervicofacial conditions.     

Spontaneous and induced minisatellite instability in the human genome

Two patients with recurrent parotid gland carcinoma required subtotal petrosectomy and infratemporal fossa type C approach. To achieve en bloc resection, the ascending mandibular ramus and the entire temporomandibular joint, including the adjacent temporal bone, were removed. An original technique for immediate reconstruction of the infratemporal region, including the glenoid fossa and the ramus of the mandible, is described. Rigid fixation, as well as good functional and aesthetic results, was achieved with autologous calvarial bone and full-thickness rib grafts, allowing the patients to mobilize their jaw very rapidly.     

An immunohistochemical study of the localization of biglycan, decorin and large chondroitin-sulphate proteoglycan in adult rat temporomandibular joint disc

To analyse regional variations in extracellular matrix components of adult rat temporomandibular joint discs, immunohistochemical techniques were used to examine the localization of two small dermatan-sulphate proteoglycans, biglycan and decorin, and a large chondroitin-sulphate proteoglycan. Staining for biglycan was intense in the posterior band, although it had a rather weak and even distribution throughout the disc. In contrast, staining for decorin was faint in the intermediate zone and the central part of the posterior band, moderate in the anterior and posterior attachments and most intense in the junction between the anterior band and attachment. The upper surface of the disc stained more intensely than the lower. Similarly, there was intense staining for large chondroitin-sulphate proteoglycan in the peripheral band, but both the anterior and the temporal parts of the posterior attachments were faintly stained. These results demonstrate marked regional differences in the expression of biglycan, decorin and large chondroitin-sulphate proteoglycan in the temporomandibular joint discs of adult rats. These variations probably reflect the different biomechanical environments caused by the complicated articulatory functions of the temporomandibular joint.     

Microbial oxidative metabolism of diclofenac: production of 4''-hydroxydiclofenac using Epiccocum nigrum IMI354292

OBJECTIVE: The purpose of this study was to examine both condylar displacement of the temporomandibular joint after sagittal split ramus osteotomy with rigid osteosynthesis and intraoral vertical ramus osteotomy without osteosynthesis in patients with mandibular prognathism by means of three-dimensional computed tomography. STUDY DESIGN: In this pilot study, five patients treated with sagittal split ramus osteotomy and 5 patients treated with intraoral vertical ramus osteotomy were evaluated. A technique to superimpose a postoperative three-dimensional computed tomography image on its corresponding preoperative image was designed. Postoperative condylar displacement, rotation, and tilting were measured in three-dimensional computed tomography images. RESULTS: Within 3 to 6 months after surgery, changes in the inclination of the condylar axes were distinctly seen, although changes in the position of the condyles within the joints were minimal. In particular, outward rotation of the condylar long axes after intraoral vertical ramus osteotomy was a frequent finding. CONCLUSIONS: The three-dimensional computed tomography superimposition technique was a practical method of evaluating postsurgical condylar displacement after mandibular osteotomy.     

Lateral displacement of the mandible in Rhesus monkeys

Lateral displacement of the mandible was induced experimentally in five adult male Rhesus monkeys. Following from 2 1/2 weeks to 19 months, the animals were sacrificed and examined histologically. Two of the monkeys received H3 proline 4 months prior to sacrifice and radioautographs were prepared. The lateral displacement apparently caused great discomfort because the monkeys refused to eat and lost weight rapidly for a few months. After about 12 months, the monkeys could again eat their normal diet to the extent they started to gain weight slowly. The histological and radio-autographic findings indicated almost no changes of the articular surfaces of the temporomandibular joints. However, extensive reorganization of the neck of the condyles was observed. Severe periodontal trauma and extensive movements of the teeth occurred in spite of the fact that the teeth in each jaw were splinted firmly together.     

Effects of posterior teeth replacement on temporomandibular joint sounds: a preliminary report

Previous reports have shown the prevalence of jaw clicking to be significantly higher in a population with missing posterior teeth compared with an dentulous population. This study presents a 2- to 5-year assessment of the effects of posterior teeth replacement on the amplitude of jaw clicking in subjects who were asymptomatic in all respects except jaw clicking. Patients requiring removable partial dentures (RPDs) were clinically and anamnestically examined and temporomandibular joint (TMJ) sounds were recorded using a modified stethoscope attached to an adjustable headgear. Amplified signals were displayed on a strip chart recorder. The amplitude of TMJ sounds at preinsertion of RPDs were 27.5 +/- 17.7 dB at opening, and 11.1 +/- 12.7 dB at closing. Similar values after prosthesis insertion were 15.8 +/- 17.0 dB and 7.4 +/- 7.5 dB, respectively. Paired t test analyses showed significant differences in the amplitude of sound for opening and closing before inserting the prosthesis (p = 0.003) and for opening before and after treatment (p = 0.014). Following replacement of posterior teeth, the clicking amplitude decreased in 68% of recordings, remained unchanged in 11%, and increased in 21%.     

The hypomobile temporomandibular joint

The hypomobile (restricted) temporomandibular joint (TMJ) is usually caused by a restricted joint capsule or by an anteriorly displaced disk. Here, painful unilateral hypomobility (19 mm jaw opening), with normal disk position, caused by voluntary immobilization after a dental procedure, was the presenting symptom. Management included inflammation control, TMJ manipulation (mobilization), and lateral pterygoid muscle relaxation. Inflammation and pain were alleviated by nonsteroidal anti-inflammatory drugs (NSAIDs) and local TMJ ice massage. TMJ mobilization was performed at every visit, to tear joint capsule adhesions and to realign collagen fibers. Exercise consisted mainly of resistive opening (the patient resists an upward force applied to the chin), with the jaw maintained at full opening. This produced lateral pterygoid muscle relaxation at full length, aiding in the restoration of a pain-free 44 mm opening.     

Aspects of the humoral immune response to Staphylococcus intermedius in dogs with superficial pyoderma, deep pyoderma and anal furunculosis

In order to evaluate the long term clinical and morphologic results of recapture of a displaced TMJ disk, we recalled for follow-up MR imaging 75 patients who had been treated by attempted disk recapture based on pre-treatment MR imaging 1-6 years earlier. The treatment included a day appliance with inclines to guide the mandible into the therapeutic position and a telescopic night appliance which prevented retrusion of the mandible during sleep. Appliance treatment was followed by rebuilding or resurfacing the posterior teeth of one arch to permanently support the mandible in the therapeutic position. After treatment of 115 joints with displaced disks, 52% of the disks were normally positioned, 23% were improved in position, and 25% showed persistent disk displacement. Symptom relief was 92% in patients with normalized (recaptured) disks, 84% in patients with improved disk position, and 49% in patients with persistent disk displacement. Failure to improve disk position occurred in 7% of the joints with anterior disk displacement and in 44% of the joints with a transverse (sideways) component to the displacement. Forty-five percent of the recaptured-disks improved in contour. We concluded that anterior mandibular repositioning was effective in the treatment of patients with reducing displaced disks primarily when the disks were displaced only in an anterior direction. This treatment can be recommended in anterior disk displacements if the patient has failed more conservative treatment measures, permanent occlusal reconstruction can be justified, and the patient understands that long-term use of a night appliance may be necessary. Anterior mandibular repositioning appears much less effective in cases with a transverse component to the disk displacement.     

Reflex jaw motions and jaw stiffness pertaining to whiplash injury of the neck

Because a so-called mandibular whiplash injury requires the absence of short-latency jaw-closing reflexes in order to explain the postulated mechanism of injury (excessive jaw opening); the authors studied the presence and absence and more importantly, the kinematics (duration, displacement, velocity, acceleration) of monosynaptic and possibly, polysynaptic myotatic (stretch) reflexes in the jaw elevator muscles. In six healthy adults jaw jerk maneuvers were elicited through a brisk tap on the chin, and surface electromyography identified elevator reflexes while translational electrognathography identified the kinematics of the reflexes. The maneuvers were done while maintaining the rest position (3% MVC) and moderate clenching of the teeth (30% MVC). Electromyography was also used to identify phasic elevator excitations during a passive brisk neck extension maneuver. A sudden and unexpected elongation of the jaw elevators released autogenic reflex responses that, in conjunction with augmented tissue elasticity (stiffness), elevated the mandible into centric occlusion within approximately 150 milliseconds. In 86% of trials, the responses occurred regardless of the prevailing resting and clenching contractile activities. There was no evidence of a depressor force that consistently would and could anchor the mandible in a position of extreme or moderate depression, the theoretical linchpin of the mandibular whiplash injury. It was concluded that the mandibular locomotor system is very efficient in maintaining the rest and intercuspal positions of the mandible. This study found no evidence corroborating the mechanism claimed to release a so-called mandibular whiplash injury.     

Prevalence of morphological changes in the surfaces of the temporomandibular joint disc associated with internal derangement

PURPOSE: The purpose of this study was to determine the prevalence of morphological changes in the superior and inferior surfaces in the temporomandibular joint (TMJ) disc and relate them to disc displacement. MATERIALS AND METHODS: Thirty TMJs obtained from fresh cadavers were studied. The TMJs were dissected, and the superior and inferior surfaces of the disc were inspected and classified as intact, irregular, or perforated. These findings were corrolated to the position of the disc. RESULTS: There was a greater prevalence of morphologic changes in the inferior (57%) than in the superior surface (17%) of the disc (P < .001). This was found for joints both with normal disc position and those with disc displacement. There was no relationship between surface irregularities of the inferior surface and the position of the disc. Perforation was seen more frequently in joints with disc displacement than in those with normal disc position. CONCLUSION: Morphologic changes in the inferior surface of the TMJ disc are more prevalent than those in the superior surface, but this is not related to disc position. However, this needs to be considered when doing arthroscopy of only the superior joint compartment.     

18F]fluorodeoxyglucose uptake in neonatal acute lung injury measured by positron emission tomography

PURPOSE: Our goal was to investigate the role of serial dynamic contrast-enhanced SPGR MRI in the nonsurgical follow-up of patients with temporomandibular joint (TMJ) pain. METHOD: Ten patients (10 joints) with internal derangement of the TMJ were imaged with T1-weighted SE and serial postgadolinium SPGR MR pulse sequences. RESULTS: On T1-weighted images prior to treatment, the disk position was normal in one joint and anteriorly displaced without reduction in nine joints. After treatment, the disk remained normally positioned in one joint, was anteriorly displaced without reduction in eight joints, and was anteriorly displaced with reduction in one joint. The dynamic study after treatment showed a decrease in contrast enhancement of the posterior disk attachment in 7 of 10 joints. These seven patients had resolution or reduction in joint pain. CONCLUSION: These results suggest an association between a decrease in contrast enhancement of the posterior disk attachment and resolution or reduction in joint pain. This association was much stronger than the association between the clinical findings and the anatomy of the disk.     

Why do we fail in aging the skull from the sagittal suture?

This study determined the variability of temporomandibular joint (TMJ) disk position in medial, central, and lateral aspects of the joint using magnetic resonance imaging (MRI). Subjects had clinical evidence of reciprocal TMJ clicking (N = 123) or restricted mandibular motion (N = 52). Eighty-nine asymptomatic volunteers provided a control group. Disk position was quantified on MRI by measuring the angle formed by a line through the middle of the condyle and perpendicular to the Frankfort plane and a line through the same midpoint of the condyle and tangential to the posterior-most aspect of the disk. The disk position in asymptomatic TMJs varied considerably with a tendency toward farther anterior placement in more lateral images. In 47 TMJs from a total of 52 TMJ5 (90%), restricted mobility was associated with anterior disk displacement (ADD) without reduction. The disk position demonstrated a mean displacement of 77 degrees without significant differences at the medial and lateral aspects of the condyle. One hundred TMJs from a total of 123 TMJs (81%) with reciprocal clicking demonstrated ADD with reduction. Tomograms revealed larger lateral displacements or rotational displacements in these joints, whereas medial images frequently showed similar ranges of disk positions as compared with asymptomatic TMJs. The results suggest that disk positions of up to +15 degrees on medial tomograms and +30 degrees on lateral tomograms should be regarded as normal variations. Furthermore, multisection analysis of all parasagittal images improved the separation between disk displacement and asymptomatic TMJs.