ABSTRACT
INTRODUCTION: This study aimed to determine whether prescribed molar intrusion, with or without virtual occlusal bite-blocks (BB), resulted in actual molar intrusion and assisted with anterior open bite (AOB) correction in adult patients treated with Invisalign clear aligners (Align Technology, Santa Clara, Calif). METHODS: A retrospective study was conducted with 36 adult patients with AOB. Subjects were divided into 2 treatment groups: planned molar intrusion (PMI) and no-PMI (No-PMI). PMI was obtained from the tooth movement tables in the ClinCheck software. Patients with PMI were further categorized by the presence or absence of virtual posterior BB (PMI-BB and PMI-No BB, respectively). Treatment success was determined on the basis of positive vertical incisor overlap in posttreatment cephalograms. Treatment changes were assessed using pretreatment and posttreatment cephalometric radiographs (Welch 2-sample t test, 95% confidence interval, P = 0.05). Finally, treatment stability was assessed at least 1-year posttreatment using the Photographic Open Bite Severity Index (POSI). RESULTS: There were 15 patients with No-PMI and 21 without PMI (total n = 36). The mean overbite change was 2.5 ± 1.0 mm for No-PMI and 3.2 ± 1.8 mm for patients with PMI (P = 0.12). All patients had positive vertical incisor overlap in posttreatment cephalograms, indicating 100% treatment success. Open bites were corrected primarily by incisor retroclination and extrusion in both treatment groups. The average measured molar intrusion for the PMI group was 0.71 mm greater than the change for the No-PMI group, but the difference was not statistically significant after controlling for potentially confounding variables (P = 0.074). A total of 14 patients from the original sample were assessed for stability using the POSI analysis. Of those, 12 (85.7%) had a POSI score of 0. CONCLUSIONS: Regardless of whether the molar intrusion was planned or not, the modality of AOB correction with Invisalign clear aligners was primarily incisor extrusion and retroclination. Overall, aligners are an effective appliance for the treatment of adult AOB. Based on our limited sample, treatment stability was similar to that reported for fixed appliances.
ABSTRACT
INTRODUCTION: This study used digital intraoral scans to evaluate how clear aligner treatment affects occlusal contacts and to determine the influence of sex and age on contact changes. Results were compared with contact changes that occur during fixed appliance therapy. METHODS: Patients included in this study were treated in a University setting and private practice. Inclusion criteria were a Class I malocclusion treated nonextraction with clear aligners and the presence of pretreatment and posttreatment digital intraoral scans. Scans were imported into specialized software, and occlusal contacts were analyzed. The effects of age and sex on contact changes during clear aligner treatment were determined. Changes in occlusal contacts were compared with changes that occur during nonextraction treatment of patients with a Class I relationship using fixed edgewise appliances. RESULTS: A total of 45 clear aligner patients fit the eligibility criteria. Clear aligner treatment reduced the percentage of tight, near, and approximating contacts, whereas the percentage of open and no contacts increased. These changes in occlusal contacts were greater for the older age group studied. Genderinfluenced occlusal contact changes in the anterior dentition only where the decrease in near contacts and increase in open contacts were greater for males. These results for patients treated with clear aligners were similar to those for patients treated with fixed appliances; both treatment modalities reduced close occlusal contacts at the time active treatment was completed. CONCLUSIONS: These results indicated that when clear aligners or fixed appliances are used to treat a Class I malocclusion, the resulting occlusion immediately after debonding is not as "tight" as it was at pretreatment.