Long-term follow-up of craniofacial alterations in juvenile idiopathic arthritis.

OBJECTIVE: To investigate changes in the craniofacial skeleton in relation to the changes in condylar alterations that occur during long-term follow-up in patients with juvenile idiopathic arthritis. MATERIALS AND METHODS: Temporomandibular joint (TMJ) involvement is defined as a condylar alteration that is observed on the orthopantomogram. Lateral cephalograms were used to determine linear and angular measurements. RESULTS: Seventy of 97 patients from the initial study cohort were included, with a mean follow-up of 68 months. The overall prevalence of condylar alterations and posterior rotation of the mandible decreased; however, the prevalence of retrognathia remained the same. Patients showed improvement in the degree of retrognathia and posterior rotation (40% ANB, 51% OP-SN, and 44% GO-GN-SN). Improvement in the degree of retrognathia was seen more often in patients with improved condylar alterations than in patients with persistent alterations and in those without alterations (50%, 33%, and 28%, respectively). The degree of posterior rotation improved almost equally in patients without TMJ involvement and in patients with improved condylar alterations (57% and 50% by OP-SN, and 67% and 38% GO-GN-SN, respectively) and did not improve in patients with stable persistent alterations. CONCLUSION: Both condylar and craniofacial alterations can improve in patients with juvenile idiopathic arthritis.

Relapse and stability of surgically assisted rapid maxillary expansion: an anatomic biomechanical study.

PURPOSE: This anatomic biomechanical study was undertaken to gain insight into the underlining mechanism of tipping of the maxillary segments during transverse expansion using tooth-borne and bone-borne distraction devices. MATERIALS AND METHODS: An anatomic biomechanical study was performed on 10 dentate human cadaver heads using tooth-borne and bone-borne distraction devices. RESULTS: The amount of tipping of the maxillary halves was greater in the tooth-borne group, but the difference was not significant. Four of the specimens demonstrated an asymmetrical widening of the maxilla. CONCLUSIONS: Segmental tipping was seen in both study groups. In this anatomic model, tooth-borne distraction led to greater segmental tipping compared with bone-borne distraction. Keep in mind, however, that this anatomic model by no means depicts a patient situation, and any extrapolation from it must be done with great care. The fact that the tooth-borne group demonstrated greater tipping might reflect the general opinion that bone-borne distraction causes less segmental angulation than tooth-borne distraction. Some tipping was seen in the bone-borne group, suggesting that overcorrection to counteract relapse will be necessary with this treatment modality.

Long-term followup of temporomandibular joint involvement in juvenile idiopathic arthritis.

OBJECTIVE: Temporomandibular joint (TMJ) involvement is a frequent feature in cross-sectional prevalence studies among patients with juvenile idiopathic arthritis (JIA). In this followup study, patients were reviewed after 5 years to study the course of TMJ involvement in relation to disease characteristics. METHODS: Children with JIA from a previous study on TMJ involvement were included. A rheumatologic evaluation including the 6 parameters of the JIA core set and an orthodontic evaluation including an orthopantomogram (OPT) were performed. OPTs were scored according to Rohlin's grading system (grades 0-5). RESULTS: The overall prevalence of patients with condylar alterations decreased from 49% to 40%. Improvement of the alterations was seen in 69% of the initially affected condyles, and consequently improvement was seen in 83% of the initially affected patients. Normalization of the alterations was seen in 67% of the improved condyles, and consequently in 44% of the patients. This proves that the condyle has a regenerative capacity. Improvement was related to low disease activity and a less extensive therapeutic regimen. CONCLUSION: In patients with JIA, condylar alterations can improve and even regenerate. Condylar improvement is associated with a low disease activity.

Osteoclastic bone resorption around intraosseous screws in rat and pig mandibles.

This report describes osteoclastic bone resorption around intraosseous fixation screws in rat and pig mandibles. These screws supported distraction devices and provided for neutral fixation following the distraction period. Progressive clinical instability of bicortical screws and radiographic and histologic evidence of osseous resorption were frequent findings. In rats, clinical evaluation revealed screw loss and/or loosening in 50% of the rats between 11 and 30 days of neutral fixation. Radiographic signs of resorption were apparent around 60% of the screws that were in place at the end of the observation period. The total rate of resorption or loss was 64 of 80 screws (80%). Histologic examination showed partial or extensive osteolysis around the screw holes in 87% of screws that were clinically fixed in the bone at sacrifice. In histologic sections of porcine specimens, osseous resorption around identifiable screw holes was present in 75% of the cases, and showed progressive increase in resorption with time. Osteoclastic resorption was common around bicortical screws that were evaluated after they had served for osseous stability.