Case report: four permanent second molar extractions

A patient who had earlier undergone four second molar extractions and who demonstrated Class II buccal segments and major incisor crowding was treated with the relatively unusual extraction pattern of maxillary lateral incisors. The treatment resolved the crowding and created Class II buccal segments with maxillary canines substituted for extracted lateral incisors. Favorable tooth anatomy produced an acceptable esthetic result accomplished with a predictable outcome over a reasonable duration of treatment. The sequential panoramic radiographs show evidence of the third molars spontaneously progressing toward positions that may result in their successful substitution for the earlier extracted second molars. A relatively unorthodox treatment plan made possible resolution of a difficult existing clinical situation using relatively routine treatment procedures.

A comparison between radiographic and sonically produced cephalometric values

Cephalometric radiography has become a standard and invaluable means of obtaining diagnostic information for the management of malocclusion and skeletal disharmony. However, concerns over radiographic exposure, particularly in growing individuals, may limit its use, especially in longitudinal analyses. Less invasive means of obtaining vital information would be desirable. A recently introduced system (Digigraph, Dolphin Imaging Systems; Valencia, Calif) provides sonically produced representations of cranial landmarks and has been introduced by its manufacturer as an alternative to standard cephalometric radiography. The purpose of the study was to compare the validity and reproducibility of cephalometric values generated sonically on a digital image analyzer (Digigraph) with those obtained from standard cephalometric radiographs for 43 different measurements. Although 58.1% of the sonically produced measurements showed significant correlation with radiographically produced measurements, there were no trends observed for correlation, either in dental or skeletal structure classifications. Additionally, this study found the data generated from the digital image analyzer to be markedly variable, while the radiographically obtained data were reproducible.

Mandibular incisor extraction--postretention evaluation of stability and relapse

Pretreatment, posttreatment and 10-year postretention dental cast and lateral cephalogram records of 42 patients were evaluated. Each patient had undergone edgewise orthodontic treatment following removal of one or two mandibular incisors and various maxillary teeth. Seven of 24 patients (29%) in the single-incisor extraction group and 10 of 18 (56%) patients in the two-incisor extraction group demonstrated unacceptable mandibular incisor alignment at the postretention stage. This result was considerably more favorable than the results of previously reported premolar extraction cases (70% unacceptable alignment at postretention). Intercanine width decreased during treatment and continued to decrease postretention in most cases. Overbite and overjet remained acceptable. No associations could be found to predict the amount of relapse.

Tomographic assessment of temporomandibular joints in patients with malocclusion

There is a paucity of information on the morphological assessment of the temporomandibular joint in relation to varying skeletal and dental relationships. The purpose of this study was to evaluate the morphologic relationship of the condyle and fossa in patients with different malocclusions and skeletal relationships. Pretreatment records of 232 orthodontic patients, 95 males and 137 females, of Caucasian descent and ranging in age from 9 years 4 months to 42 years 6 months, were examined. Records included dental casts, lateral cephalometric radiographs, hand-wrist radiographs, and corrected tomograms of right and left TM joints. Nonconcentricity and mild asymmetry of the condyle-fossa relationship were commonly observed. The left condyle was found to be more anteriorly positioned than the right, with the mean percentage of joint space being 6.93% on the left side and -1.24% on the right. Skeletal and dental Class III patients demonstrated significantly more anteriorly positioned condyles (P < 0.05). There were no significant differences in condylar position between Class I and Class II groups based on ANB or Angle's classification. Further, no significant difference in condylar position was observed between groups based on overbite or crossbite.