Comparison of clinical outcomes between Invisalign and conventional fixed appliance therapies in adult patients with severe deep overbite treated with nonextraction.

INTRODUCTION: The use of aligner therapy for orthodontic treatment has increased substantially in the past decade. However, no study has compared treatment outcomes between the conventional fixed appliance and Invisalign therapies in patients with a severe deep overbite. METHODS: This study included 50 consecutive adult patients who underwent treatment with either Invisalign (n = 25; mean age, 23.3 ± 8.5 years) or a conventional fixed appliance (n = 25; mean age, 23.1 ± 6.5 years) to correct overbite >5 mm and >60% deep overbite. Cephalometric analysis and peer assessment rating was used to compare the clinical outcome between groups. RESULTS: Cephalometric analysis showed significant differences in N-Me (P = 0.0005) and Mp-L6 (P = 0.0001) between Invisalign and fixed appliance treatment groups. No significant differences were observed in the peer assessment rating analysis or total treatment duration between the 2 groups. CONCLUSIONS: Both Invisalign and conventional fixed appliances were effective in treating patients with a severe deep overbite. Invisalign therapy may be preferable over conventional fixed appliance therapy in patients with high angle and deep overbite. However, because this study had a retrospective design, the results should be viewed with caution.

Analysis of pain level in cases treated with Invisalign aligner: comparison with fixed edgewise appliance therapy.

BACKGROUND: The aim of this study was to evaluate and compare the difference in the level of pain using the visual analog scale (VAS) between cases treated with the edgewise appliance and Invisalign. In addition, the cause of pain and discomfort in the Invisalign cases was identified. METHODS: The sample consisted of 145 cases for the edgewise group (EG; n=55), Invisalign group (IG; n=38), and edgewise and Invisalign group (EIG; n=52). VAS scores were collected during the first three stages (first stage: 0 to 7 days, second stage: 14 to 21 days, and third stage: 28 to 35 days) and at the end of the treatment (overall VAS score). Evaluation of the cause of pain was categorized into three different types of problem (category 1: non-smoothed marginal ridge or missing materials, category 2: deformation of attachments, and Category 3: deformation of the tray). Statistical comparison of VAS scores between groups was performed by two-way analysis of variance. RESULTS: A significantly higher VAS score was observed at 3 and 4 days after, at 1, 2, and 3 days after, and at 2 and 3 days after in stages 1, 2, and 3, respectively, in EG compared to EIG and IG. A significant difference was observed in overall VAS scores between EG and IG in intensity of pain, number of days that pain lasted, and discomfort level. Only intensity of pain resulted in a significant difference between EG and EIG. Most of the causes of problem in the Invisalign cases were deformation of the tray. CONCLUSIONS: Invisalign may offer less pain compared to the edgewise appliance during the initial stages of treatment. In the use of Invisalign, deformation of tray must be carefully checked to avoid pain and discomfort for the patients.

Evaluation of optimal length and insertion torque for miniscrews.

INTRODUCTION: The purpose of this article was to test the theory that short miniscrews will decrease the possibility of damaging the root, but the failure rate will increase. METHODS: One hundred eighty-six miniscrews (diameter, 1.3 × 5 mm, n = 63; 6 mm, n = 62; 7 mm, n = 61) were placed in 105 consecutive patients. Multislice computed tomography and cone-beam computed tomography scans were taken before and after miniscrew placement. Insertion torque was measured at miniscrew placement. RESULTS: The success rate of the miniscrews in the maxilla (93.4%) was higher than that in the mandible (70.3%). A significantly lower success rate with 5-mm miniscrews was observed compared with 6-mm and 7-mm miniscrews in the mandible. Miniscrews placed in less than approximately 3.8 mm of bone and those within 1.4 mm of the root had significantly higher failure rates. Miniscrews placed with insertion torque greater than 10 Ncm had a tendency for a lower success rate. CONCLUSIONS: The optimum lengths of miniscrews of a diameter of 1.3 mm are 5 mm in the maxilla and 6 mm in the mandible. They should be placed at a distance from the root with insertion torque less than 10 Ncm for safe orthodontic anchorage without failure.

Clinical effect of CO(2) laser in reducing pain in orthodontics.

OBJECTIVE: To test the hypothesis that there is no difference in the pain associated with orthodontic force application after the application of local CO(2) laser irradiation to the teeth involved. MATERIALS AND METHODS: Separation modules were placed at the distal contacts of the maxillary first molars in 90 patients in this single-blinded study. In 60 of these patients (42 females and 18 males; mean age = 19.22 years) this was immediately followed by laser therapy. The other 30 patients (18 females and 12 males; mean age = 18.8 years) did not receive active laser irradiation. Patients were then instructed to rate their levels of pain on a visual analog scale over time, and the amount of tooth movement was analyzed. RESULTS: Significant pain reductions were observed with laser treatment from immediately after insertion of separators through day 4, but no differences from the nonirradiated control side were noted thereafter. No significant difference was noted in the amount of tooth movement between the irradiated and nonirradiated group. CONCLUSIONS: The hypothesis was rejected. The results suggest that local CO(2) laser irradiation will reduce pain associated with orthodontic force application without interfering with the tooth movement.