Clinical, radiographic and MRI findings of the temporomandibular joint in patients with different rheumatic diseases.

The aim of this study was to investigate the condition of the temporomandibular joint (TMJ) in patients with different rheumatic diseases, and report correlations between the clinical, radiographic and magnetic resonance imaging (MRI) findings. The 67 patients were divided into four groups: 16 with rheumatoid arthritis (RA), 15 with mixed connective tissue disease (MCTD), 18 with ankylosing spondylitis (AS) and 18 with spondyloarthropathy (SPA). They were clinically examined, and panoramic tomography, lateral panoramic radiography and MRI of the TMJ were performed. MRI showed reduced articular cartilage in 25% (4/16) of RA, 0% (0/15) of MCTD, 17% (3/18) of AS and 17% (3/18) of SPA patients. Condylar changes included erosion, osteophytes and abnormal shape. Disc alterations included perforation, abnormal anterior position and decreased movement. These abnormalities were most frequent in RA patients, and least frequent in MCTD and SPA patients. Crepitation and reduced maximum opening of the mouth correlated with abnormalities of the disc and articular cartilage as shown by MRI. Severe condylar erosion in panoramic tomograms significantly correlated with MRI findings of condylar erosion (P<0.01), diminished thickness of condylar cartilage, abnormal condylar shape, and abnormal shape of the temporal surface of the TMJ (P< or =0.001). The presence of crepitation, limited mandibular movement and/or pain on movement of the jaw often indicated structural damage to the TMJ. Panoramic radiographs provide an alternative method to MRI but, to obtain a more detailed anatomic picture, MRI is recommended for patients with acute unexplained pain or as part of preoperative work up. A panoramic recording is not indicated when MRI is planned.

The desmoid tumor. II. Analysis of factors possibly contributing to the etiology and growth behavior.

Eighty histologically verified cases of the desmoid tumor (DT) have been analyzed with regard to factors possibly contributing to the etiology and/or growth behavior of this uncommon neoplasm. Considering the four statistical age components, the "fertile" female and "menopausal" varieties of the DT grew distinctly faster (0.1 less than P greater than 0.05 and less than 0.05), and the female "juvenile" variety distinctly slower (0.1 less than P greater than 0.05) than the male DTs. In a visual estimate, the fertile female patients had a significant (P less than 0.01) predisposition to estrogen predominance, while fewer patients than expected displayed progesterone predominance or were at balance (P = NS and less than 0.01, respectively). Thirty-two per cent of the patients with an abdominal DT had been previously operated in the region of subsequent tumor growth. Significantly more pregnancies were observed in patients with abdominal DT than with extra-abdominal DT (P less than 0.05). On only one occasion did sigmoideoscopy reveal colonic polyposis (Gardner's syndrome). The most striking observation was, however, that up to 80% of the affected patients (compared with less than 5% in the normal control population, P less than 0.05) had multiple minor bone anomalies demonstrable by x-ray screening of the mandible, chest, and long bones. We suggest that a generalized (inherited or mutant) defect in growth regulation of connective tissue is the most important underlying cause for the DT. However, the other factors, including hormonal effects, trauma, and pregnancy contribute to the growth behavior of the tumor.

Biodegradable semirigid plate and miniscrew fixation compared with rigid titanium fixation in experimental calvarial osteotomy.

OBJECT: To determine the biocompatibility and suitability of resorbable plates and miniscrews, consolidation of symmetrical, bilateral frontal bone craniotomies that had been closed using various methods was studied in 20 growing lambs. METHODS: Bone fixation with a flexible, punched polylactide plate and four slowly degradable, self-reinforced poly-levolactide (SR-PLLA) or rapidly degradable, self-reinforced polyglycolide (SR-PGA) miniscrews (10 animals in each group) was compared intraindividually with rigid fixation by using a titanium miniplate and four miniscrews. Plain x-ray films, magnetic resonance images, histological studies, and histomorphometric studies were obtained at 4 to 104 weeks. CONCLUSIONS: No dislocation, instability, clinical foreign body reactions, infections, or loss of fixation were observed. Bone consolidation of the 2.35-mm-wide craniotomy lines was incomplete; connective tissue-filled defects through the bone were observed in 13 of 28 lines at 26 to 52 weeks. Statistical analyses based on histomorphometric studies showed no difference in consolidation with SR-PLLA miniscrew and titanium plate/screw fixation or between the two resorbable fixation methods. Fixation with rapidly degradable SR-PGA miniscrews resulted in less effective consolidation than on the contralateral titanium-treated side (p<0.05), but the bone segment was thicker (p<0.005). The SR-PGA miniscrews had disappeared by 6 weeks, the polyactide plate by 104 weeks, and the SR-PLLA miniscrews had been mostly resorbed at 104 weeks. Passive translocation of the titanium plates and screws into the bone tissue was seen at 52 and 104 weeks. In rapidly growing lamb frontal bone, comparable consolidation results, without complications, can be achieved with semi-rigid resorbable fixation compared with rigid metallic fixation.

Long-term stability of two different mandibular bridging systems.

To evaluate the benefits of narrow-beam roentgenography and spiral tomography for examination and monitoring of screw and plate fixation to bone we studied 22 rigid plate bridgings of mandibular defects. The plate reconstructions were of long duration or considered permanent. In 13 patients, AO-THORP (AO: Arbeitsgemeinschaft für Osteosynthesefragen; THORP: Titanplasma-beschichteten Hohl- und Vollkern-Rekonstruktionsplatten-Systems) reconstructions were used and in nine classic AO stainless steel plate bridgings. With the AO-THORP system, good bone apposition to the screws was evident in 96% (73/76 screws) of the cases. Fixation using the classic AO screws, however, was inadequate in 30% (20/66 screws) of the cases. Plate loosening was noted in 56% (5/9 plates). Examination using narrow-beam roentgenography and spiral tomography provided detailed information about bone resorption around the screws and provided a reliable tool for deciding on a follow-up regimen. When complications occur, they can be detected and treated early, reducing patient morbidity. In our opinion, classic AO plate bridging should always be considered temporary.

Midfacial fractures in pediatric patients. Frequency, characteristics, and causes.

OBJECTIVE: To determine the frequency, characteristics, and causes of midfacial fractures in children. DESIGN: A retrospective review of the patients' medical charts and radiographs. SETTING: Tertiary referral center. PATIENTS: Fifty-four patients under 16 years of age, with midfacial fractures diagnosed and treated in the Helsinki (Finland) University Central Hospital from 1980 through 1992. MAIN OUTCOME MEASUREMENTS: The data examined included sex, age, time and cause of the accident, type and location of the fractures, the presence and location of associated injuries, complications, and treatment methods. RESULTS: The male-to-female ratio was 1.16:1. Motor-vehicle accident was the most common cause of injuries. The frequency of injuries was in decreasing order: (1) maxillary alveolar bone, (2) zygoma, and (3) Le Fort fractures of the maxilla. The majority of injuries occurred in subjects who were 13 to 15 years old. In children less than 6 years old, only alveolar fractures occurred. For the other age groups, no significant difference in the fracture pattern was found. No fatalities occurred in this patient series. CONCLUSIONS: Midfacial pediatric fractures are rare. A high velocity force, such as that from a motor-vehicle accident is a factor producing the injury. Owing to the high impact, associated injuries are common. The severity of the insult is more essential than the age of the patient and the development of the paranasal sinuses.

Panoramic zonography in radiographing the carpus.

The panoramic radiography technique enables the visualization of different image layers. In the search for a method for improving the radiological fracture diagnosis of the carpal bones the suitability of this technique for visualization of the carpal bones was tested. For panoramic zonography, Zonarc (Palomex, Finland) and its programme with cylindrical image layer with 85 mm radius was used. The present study showed that panoramic technique is suitable for discerning the carpal bones but not for demonstrating their skeletal details.

Panoramic zonography in ear radiography.

Thirty ears in 15 patients were examined by plain film radiography and by panoramic zonography with two tracks: A cylindrical concave image layer with 26 mm. radius and a paired sagittal image layer, at 51 mm. distance from midline. The films were interpreted according to the visibility of 23 different anatomic details. On panoramic films the visualization was better in 14 details, equal in 6 and worse in 3 compared to the plain films. The result suggests that panoramic techniques can replace conventional radiography of the ear.

Comparison of the visibility of the anatomical structures of the facial skeleton in panoramic zonography and linear tomography.

The value of cylindrical panoramic radiography (using one rotational axis), a modification of orthopantomography (using three rotational axes), in radiographic examination of maxillo-facial skeleton was estimated by evaluating the visualization of anatomical structures of the facial skeleton on cylindrical panoramic and linear tomographic radiographs of 51 patients examined with both methods. The radiographs were independently reviewed by four radiologists. The visualization of the lateral wall of the orbit and maxillary sinus, nasal septum, alveolar process and zygomatic corpus was better on cylindrical panoramic radiographs. Linear tomography visualized the media wall of orbit better. In visualizing the frontal sinus, orbital floor, medial wall of maxillary sinus and hard palate there were no significant differences between linear tomography and panoramic zonography.

Radiation doses during panoramic zonography, linear tomography and plain film radiography of maxillo-facial skeleton. A comparative study.

The radiation doses to the organs and the skin of the head and neck during plain film radiography, a-p and p-a linear tomography and panoramic zonography of the maxillo-facial skeleton were measured on a sliced anatomic Alderson skull phantom with LiF (TLD-100) thermoluminescence chips. The doses were clearly highest during the linear tomography. Also the doses during the plain film radiography were quite high. Compared to the conventional methods the doses from the panoramic Zonography were minimal.

Panoramic zonography in evaluation of recurrent basal cell carcinoma of the face.

Nine patients with recurrent, facial basal cell carcinoma were followed up both clinically and radiographically using a panoramic technique. A cylindrical image track was used for panoramic radiography. Five patients had bony destruction due to tumour re-occurrence, four patients had bony defects caused by surgery. The confirmation of the results by surgery and/or follow-up shows that the spread of basal cell carcinoma into bone can be diagnosed using a panoramic technique.

Effect of radiologist supervision on technician performance and image quality in radiography of middle face trauma.

Image quality in radiography of middle face trauma was compared within and outside office hours on the basis of the visibility of diagnostically important structures, and an evaluation of the major patient- and technician-related factors influencing image quality. Image quality was statistically significantly better within than outside office hours. This was due to the technician-related factors of patient positioning, X-ray beam limiting and centering. Since the analysis of variance revealed that alcohol intoxication (three times more common outside than within office hours) had no statistically significant effect on image quality, the difference must have been due to the only remaining variable--radiologist supervision, which was present only within office hours.

The effects of clinical data on radiological diagnostic performance in middle-face trauma.

To determine the effect of clinical information on the radiological diagnostic performance in middle-face injury, the medical records and radiographs of 618 patients with middle-face injury were reviewed. The information value of clinical data given in each x-ray requisition was evaluated. The radiological diagnoses were compared with the final clinical diagnoses both retrospectively and prospectively (with and without clinical data). Knowledge of clinical data with statistical significance changed the reader's decision threshold towards improved sensitivity but poorer specificity. Clinical data did not improve the radiologists' performance. Clinical data may be helpful in diagnostic tasks rather by increasing the sensitivity than the specificity.

Different patterns of mandibular fractures in children. An analysis of 220 fractures in 157 patients.

157 paediatric patients with a total of 220 mandibular fractures were evaluated retrospectively. All patients had been examined with the aid of orthopantomography. 72% of the children had fractures in the condylar region. The patients were divided into four age groups according to the development of the dentition (group A: 0-5 years, B: 6-9 years, C: 10-12 years, and D: 13-15 years). Bicycle accidents and falls were the two main causes of the fractures in all age groups. However, there were significant differences in the causes and location of the fractures between groups A+B and C+D. The proportion of condylar fractures decreased and the proportion of body and angle fractures increased with increasing age; fractures in the horizontal part of the mandible were mainly observed in groups C and D. Both aetiological factors and fracture patterns in the patients older than 10 years of age resembled those of adults. The differences observed should be taken into consideration in studies concerning mandibular fractures in paediatric patients. In this respect the age limit between the adult and child should probably be lowered significantly.

SR-PLLA and SR-PGA miniscrews: biodegradation and tissue reactions in the calvarium and dura mater.

The biocompatibility and degradation of self-reinforced poly-L-lactide (SR-PLLA) and polyglycolide (SR-PGA) miniscrews, vs titanium miniscrews, was studied in frontal bone osteotomies in 20 lambs, where they were used for plate fixation. At follow-up at 4, 6, 12, 26, 52 and 104 weeks, no clinical foreign body reaction, infection or other complications had occurred. Histologically, PGA material was hydrolyzed and fragmented at 4-6 weeks and was resorbed by 12 weeks, whereas the SR-PLLA miniscrews retained their integrity and holding power for 26 weeks and were mostly resorbed at 2 years. According to histological and histomorphometric analyses and plain film radiography, the degradation of PGA miniscrews was accompanied by a typical non-specific foreign-body reaction and initial transient osteolysis with decreased osteoid formation around the screw channel, but compensatory intense osteoid formation and bone remodelling followed after resorption of the polymer. The foreign body reactions to PLLA and titanium were considerably milder. All miniscrews were commendably strong and could be satisfactorily tightened against the plate. SR-PLLA miniscrews offer fixation stability for half a year, whereas rapidly degrading SR-PGA miniscrews may be used when short-term fixation is needed.

A new method of reconstruction in a patient undergoing bilateral total maxillectomy.

A new application of the titanium hollow screw reconstruction plate (THORP) system, originally designed for bridging mandibular defects, is presented. Because of the screw-plate locking principle, the system allows rigid fixation of the plate without unphysiologic load to the bone underneath. A case is presented with a large squamous cell carcinoma requiring bilateral total maxillectomy. The titanium plate was attached horizontally to the zygomatic bones with two titanium hollow screws on each side. Six months later a prosthetic device was constructed and attached to the exposed part of the plate by a modified bar and clips system. The patient is able to speak, chew, and swallow without difficulty.

A comparative study on four screw-plate locking systems in sheep: a clinical and radiological study.

Four mandibular screw-plate locking systems were studied in sheep. Three to four centimetres angular continuity resections of the mandible were performed and the defects bridged with pre-bent angular reconstruction plates fixed with four screws in the body part and three in the ramus. Each type was used four times. Clinical and radiological examinations were carried out 1 and 2 months later. All sheep were able to eat and ruminate normally throughout the postoperative period. Radiology revealed that 6/16 plates and 5/112 screws fractured during the follow-up period. In one type, no fracture occurred. Screw fracture was confined to just one reconstruction system. Six of 16 mandibles showed slight to moderate bone resorption under the plate. The results point to the internal shortcomings of the systems tested.

Orbital floor reconstruction with poly-L/D-lactide implants: clinical, radiological and immunohistochemical study in sheep.

In this study the reconstruction capacity of orbital wall in sheep was evaluated when poly-L/D-lactide (PLDLA96) implants were used for large blow-out defects in 18 sheep. The contralateral side, where the defects healed spontaneously, served as controls. The follow-up was 12, 16, 22 and 36 weeks. Healing was evaluated clinically, radiologically, histologically and immunohistochemically. Physiochemical properties of the implants were also studied. At first, the implants were surrounded by elastic capsules, which gradually ossified. At 36 weeks, 60% were still visible and deformed but surrounded by bone. Light microscopy revealed a low grade inflammatory reaction. Expression of Tn-c and cFn was intense throughout the study. Shear strength decreased gradually and was not measurable after 16 weeks. Crystallinity increased steadily from 1.5 to 29.30% and molecular weight decreased from 49,000 to 4186. In CT, the final bony defect was smaller in the reconstructed sides than in the controls. Based on this study it can be concluded that PLDLA96 implant provokes a local inflammation, which does not prevent bone healing. The deformation of the implant, however, indicates that this PLDLA96 plate is not suitable for orbital floor reconstruction.

Radiologic changes of the temporomandibular joint after condylar fractures in childhood.

OBJECTIVE: The purpose of this investigation was to study the radiologic outcomes of pediatric condylar fractures. STUDY DESIGN: Radiographs of 37 patients with 45 condylar fractures that had been diagnosed at the Department of Oral and Maxillofacial Surgery, Helsinki University Central Hospital were retrospectively reviewed. The frequency and characteristics of incomplete remodeling at an average of 4.1 years after the injury were studied. The influence of age and fracture type on remodeling were considered. RESULTS: Incomplete remodeling was observed after 56% of the fractures. The most frequent signs of incomplete remodeling were alteration in the configuration of the surface of the condylar head and deformation of the condylar neck. Incomplete remodeling was frequently (83%) related to fracture dislocation. For this fracture type the radiologic prognosis seems poor in all age groups. A difference in ramus height between the 2 sides was observed in 52% of the fractures, particularly frequently (80%) after fracture dislocation. CONCLUSIONS: Radiologic aberrations are frequent after pediatric condylar fractures. Dislocated fractures, in particular, need special attention and long-lasting clinical follow-up.

An epidemiological study of patterns of condylar fractures in children.

OBJECTIVE: To find out how the site and type of condylar fracture are affected by its aetiology and the age and sex of the patient. DESIGN: Retrospective study. SETTING: Tertiary referral centre, Finland. MATERIAL: Radiographs of 101 children (aged 15 years or less) with 119 condylar fractures. MAIN OUTCOME MEASURES: Site of fracture and degree of displacement. RESULTS: A total of 26 of the 119 fractures were intracapsular (22%) and 93 (78%) extracapsular. Only among patients less than 6 years of age was there a preponderance of intracapsular fractures (7/12 fractures in 10 patients, 58%). In the older children 78% (83/107) were in the condylar neck. There were few subcondylar fractures (5/119, 4%). Only 6 fractures were displaced (5%). Dislocation of the condyle from the glenoid fossa was common in all age groups. CONCLUSION: The site of condylar fracture is age related, but not associated with sex or aetiology.

History of panoramic radiography.

The first attempts to image the whole jaw were made with intraoral radiation sources at the beginning of this century. The narrow-beam principle was described in 1922. Experimental work and development of equipment in the 1950s resulted in commercially available machines in the early 1960s. The panoramic technique originated from the need to image the jaws, but it was also applied to other anatomic regions, before CT became available. Panoramic radiography is an essential element in oral radiology today.