Relapse tendency after orthodontic correction of upper front teeth retained with a bonded retainer.

OBJECTIVE: To investigate the amount and pattern of relapse of maxillary front teeth previously retained with a bonded retainer. MATERIALS AND METHODS: The study group consisted of 135 study casts from 45 patients. Recordings from study models before treatment (T1), at debonding (T2), and 1 year after removal of the retainer (T3) were present. All patients had been treated with fixed edgewise appliances. The irregularity index (sum of contact point displacement [CPD]) and rotations of front teeth toward the raphe line were calculated at T1, T2, and T3. RESULTS: The mean irregularity index at T1 was 10.1 (range 3.0-29.9, SD 5.4). At T2 it was 0.7 (range 0.0-2.1, SD 0.7), and at T3 it was 1.4 (range 0.0-5.1, SD 1.2). Fifty-five teeth in 42 patients were corrected more than 20 degrees between T1 and T2 (mean correction 31.4 degrees range 20.0-61.7), and mean relapse in this group was 7.3 degrees (range 0.0-20.5). Regarding alignment of the maxillary front teeth, the contact relationship between the laterals and centrals seems to be the most critical. A significant positive correlation was found between the amount of correction of incisor rotation and the magnitude of relapse but not between the amount of correction of CPD and the magnitude of relapse. Eighty-four percent of the overcorrected CPDs returned to a desired position. CONCLUSIONS: Minor or no relapse was noted at the 1-year follow-up.

Malocclusion and temporomandibular disorder: a comparison of adolescents with moderate to severe dysfunction with those without signs and symptoms of temporomandibular disorder and their further development to 30 years of age.

A total of 1018 subjects were examined at the age of 11 years, 791 were reexamined at 15 years, 456 at 19 years, and 337 at 30 years. Anamnestic and clinical recordings of temporomandibular disorder (TMD) were made. Morphology, including calculation of peer assessment rating (PAR) scores, was recorded. Previous history of orthodontic treatment was assessed. Muscular endurance was recorded. The subjects completed four psychological measures. The malocclusion prevalence, occlusal contacts, psychological factors, and muscular endurance in subjects with no recorded signs and symptoms of TMD were compared with those with the most severe dysfunction at 19 years of age. The further development of TMD to 30 years of age was followed. PAR scores were significantly higher in the subjects with the most severe dysfunction. Apart from crowding of teeth, no other significant differences were found between the groups with regard to separate malocclusions, tooth contact pattern, orthodontic treatment, or extractions. A greater proportion of subjects with low endurance were found in those with TMD. Significant associations between TMD and general health and psychological well-being as well as the personality dimension of neuroticism and self-esteem were found. During the period from 19 to 30 years, the prevalence of muscular signs and symptoms showed considerable reduction, whereas clicking showed a slight increase. Locking of the joint showed a decrease from 19 to 30 years. One-quarter of the TMD subjects showed complete recovery. Thus, orthodontic treatment seems to be neither a major preventive nor a significant cause of TMD.

Pattern and amount of change after orthodontic correction of upper front teeth 7 years postretention.

OBJECTIVE: To investigate the amount and pattern of changes of maxillary front teeth 7 years postretention, which previously were retained with a bonded retainer. MATERIALS AND METHODS: The study group consisted of 27 patients. Study models before treatment (T1), at debonding (T2), 1 year after removal of the upper bonded retainer (T3), and 7 years postretention (T4) were present. The irregularity index (sum of contact point displacements) and the rotations of front teeth toward the raphe line were calculated. RESULTS: The irregularity index of the maxillary front teeth changes very little or not at all during the first year postretention. Further change long term resulted in an irregularity index of mean 2.0 (range 0.0-5.8). The contact relationship between the laterals and centrals seems to be the most critical. Forty rotated teeth in 21 patients were corrected more than 20 degrees . Mean relapse during the first year postretention was 6.7 degrees (range 0.0 degrees -14.7 degrees ). Mean changes during 7 years was 8.2 degrees (range 0.0 degrees -19.3 degrees ). CONCLUSIONS: Relapse of upper front teeth retained with a bonded retainer is minor in both the short and long term. If permanent retention is required after 3 years of retention, it is enough to retain the incisors.