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.

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.

HLA-DRB1* alleles and temporomandibular joint erosion in patients with various rheumatic diseases.

OBJECTIVE: To investigate the association between HLA antigens and temporomandibular joint (TMJ) erosion, salivary composition, and focal sialadenitis in patients with rheumatic diseases. METHODS: Eighty-four patients, 24 with rheumatoid arthritis (RA), 19 with mixed connective tissue disease (MCTD), 19 with ankylosing spondylitis (AS), and 22 with spondyloarthropathy (SPA) were studied. Each patient underwent clinical examination of the masticatory system, unstimulated and stimulated saliva collection, and minor salivary gland biopsy. Radiographs (OPTG) of the TMJ were obtained, and HLA allele (A, B, C and DRB1*) analysis was performed. Erosion in OPTG was scored from 0 (no erosion) to 4 (condyles totally eroded). In the analysis, scores 0-2 were grouped as normal or mild changes, and scores 3-4 as distinct erosions. One hundred healthy blood donors served as controls for HLA typing. RESULTS: Distinct erosion of the TMJ in OPTG was observed in 22 (27%) patients. It affected four (17%) of the 24 patients with RA, three (17%) of the 18 with MCTD, seven (37%) of the 19 patients with AS and eight (38%) of the 21 with SPA non-significant (NS). The mean erosion scores were 1.7 for RA, 1.3 for MCTD, 2.5 for SPA, and 1.6 for AS patients [probability (p) = 0.04]. The frequency of HLA-B27 antigen was higher in the AS and SPA patients, and that of HLA-DRB1*04 allele higher in RA patients than in control subjects. In the whole patient population, HLA-DRB1*01 allele was significantly associated with erosions 16/36 (44%) versus 6/46 (131%1) (p = 0.0014). In the SPA group, patients with HLA-DRBI*01 allele had a significantly higher occurrence of distinct erosions than patients without this allele [8/10 (80%) versus 0/11 (0%) (p = 0.0002)], whereas DRB1*06 was protective [0/8 (0%) versus 8/13 (62%) (p = 0.018)]. HLA-DRB1*04 was associated with increased salivary IgG in the RA patients. CONCLUSION: HLA antigens are significantly associated with the development of destructive lesions in the TMJ, as well as composition of saliva in patients with various rheumatic diseases.

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.

Condylar process fractures in children: a follow-up study of fractures with total dislocation of the condyle from the glenoid fossa.

PURPOSE: The purpose of this study was to investigate the long-term clinical and radiologic outcome of nonsurgically treated, dislocated condylar fractures sustained during childhood. PATIENTS AND METHODS: Dislocated condylar process fractures were diagnosed in 34 children aged 15 years or younger from 1980 to 1991. Of these, 26 had been treated nonsurgically and were asked to participate in a follow-up examination. Eighteen patients, representing 69% of the total sample, took part in the study. All patients underwent a clinical investigation with special emphasis on temporomandibular joint (TMJ) function. The patients also underwent a radiologic investigation, focusing on fracture remodeling and symmetry of the mandible. RESULTS: After a follow-up period ranging from 4.8 to 16.4 years (mean, 8.6 years), 56% had some subjective symptoms, and 72% had some objective signs of TMJ dysfunction. In general, however, the symptoms and signs of dysfunction were very slight. No correlation was observed between the method of nonsurgical treatment and the clinical results. Radiologic investigation showed incomplete remodeling (76.5%) and asymmetry of the mandible (64.7%) in most patients. The asymmetry was slight, however, and could not be observed clinically. CONCLUSIONS: Conservative treatment of dislocated condylar process fractures in children results in satisfactory long-term outcome of jaw function despite a high frequency of radiologically noted aberrations. Soft diet with immediate mobilization seems to be the treatment of choice.

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.

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.

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.

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.

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.

Decortication in the treatment of diffuse sclerosing osteomyelitis of the mandible. Retrospective analysis of 41 cases between 1969 and 1990.

Thirty-four patients with mandibular diffuse sclerosing osteomyelitis who had been treated by means of 61 decortications were evaluated retrospectively. Eighteen patients (53%) were free from symptoms on an average of 5.4 years after surgery. Of these, 12 had improved after their first operation. In the other six patients, decortication was performed two to four times before healing was clinically observable. Symptoms recurred in 75% of the cases within 12 months after surgery. Neither sex, location, extent, and chronicity of the disease nor the precise surgical technique used seemed to affect the outcome. The patients who exhibited improvement, however, were significantly older and more often edentulous than the patients in whom the symptoms recurred. Possible causes of failure were an insufficiently radical surgical procedure and retention of devitalized teeth in the decorticated area.

Cross-sectional tomography in evaluation of patients undergoing sagittal split osteotomy.

A study was performed to evaluate the possibility of locating the mandibular canal before sagittal split osteotomy by cross-sectional spiral tomography in 55 patients. Visibility of the whole canal wall circumference was excellent or good in 65.5% fair in 18.2%, and poor in 12.7% of cases. Only four canals (3.6%) were invisible. The canal was located lingually in 61 cases, buccally in 9 cases, and centrally in 34 cases. In patients with mandibular protrusion, the mean (+/- SD) buccolingual width was significantly smaller (9.5 +/- 1.51 mm vs 10.4 +/- 1.46 mm, P < .01) and the mandibular canal was more often buccally located than in patients with retrognathia.

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.

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.

Erosion and heterotopic bone formation after alloplastic temporomandibular joint reconstruction.

Twenty-three temporomandibular joint arthroplasties using metallic condylar prostheses were performed because of severe ankylosis (8 patients), segmental mandibular resections in tumor surgery (9 patients), and after extensive trauma (2 patients). A clinical and radiological follow-up study showed heterotopic bone formation in 52% of cases and glenoid fossa resorption in 43%. In one patient with rheumatoid arthritis the condyle eroded through the skull base 10 months after surgery. Seven prostheses (30%) were removed and/or exchanged during the average 27.6-month follow-up.

Radiologic follow-up of bone transplants to bridge mandibular continuity defects.

Special radiologic imaging techniques were used to evaluate the results of nonvascularized bone grafts combined with rigid mandibular reconstruction plates. The radiologic findings divided 21 cases into three clearly distinct groups on the basis of resorption: slight (less than 15%), moderate (15% to 30%), and massive (more than 30%) (mean follow-up, 26 months). This division predicted the clinical results well. In contrast to earlier reports, it was shown that rigid plate bridging did not adversely influence the prognosis of the graft. Nor was early plate removal necessary to reach good ossification. Narrow-beam radiography and spiral tomography proved to be excellent tools for adequate evaluation of bone resorption and bony healing of mandibular grafts.

Comprehensive oral X-ray diagnosis: Scanora multimodal radiography. A preliminary description.

Scanora (Soredex, Orion Corporation, Helsinki, Finland) is a multimodal radiography system which utilizes the principles of narrow beam radiography and spiral tomography. The system includes an integrated multifunction X-ray unit, a coordinate system for object localization and a wide selection of dental and maxillofacial imaging problems. All imaging procedures are computer controlled and executed automatically. Clinical experience and preliminary results show that the multimodal imaging system has great potential in the detection of pathological conditions of the maxillofacial region.

Severe bone resorption and osteoarthrosis after miniplate fixation of high condylar fractures. A clinical and radiologic study of thirteen patients.

Thirteen cases of high condylar fracture treated by open reduction and fixation with miniplates were monitored for an average of 18 months postoperatively. Satisfactory functional results were achieved clinically in all but one patient. Radiologically, however, signs of condylar resorption and osteoarthrosis were diagnosed in all patients. In four patients with associated multiple fractures of the facial bones, rapid complete resorption of the condyle was observed. These changes were markedly more severe than those observed in our previous study, in which osteosynthesis was performed by transosseous wiring and subsequent intermaxillary fixation for 3 to 7 weeks. Indications for rigid and nonrigid fixation in the surgical treatment of condylar fractures are discussed.