Photoelastic analysis of tension distribution in different orthodontic approaches for closing anterior open bites.

BACKGROUND: This study aims to evaluate tension distribution in the anterior region of the mandible during two orthodontic mechanical approaches to treat anterior open bite. METHODS: It was an in-vitro experimental study, that analyzed 5 models of photoelastic resin, simulating a lower dental arch. The anterior teeth underwent orthodontic forces of the Blue Elgiloy® 0.016" x 0.022" (MEAW technique) and Gummetal® 0.018"x 0.022" (GEAW technique) archwires. Tension distribution was assessed on three different points in the lower dental midline and was measured using a reflection polariscope. The archwires were evaluated with and without anterior elastic bands (6 oz, 170 g) installed between lateral incisors and lower canines, as recommended for anterior open bite. RESULTS: The highest magnitudes of tension generated by the archwires were observed in the cervical regions of the teeth (on average 50% higher than those at the most apical point) regardless of the technique used. Comparatively, the GEAW technique showed significantly (P<0.05) lower tension values (16 MPa) than the MEAW technique using Blue Elgiloy (24 MPa). CONCLUSIONS: The GEAW technique showed a more favorable tension distribution pattern than the MEAW approach. The use of elastic bands improved tension distribution, regardless of the technique. The results also suggest that the use of anterior elastic bands in both techniques reduced the tensions released by the intrusive forces generated by the archwires.

An Alternative Approach for Space Opening in a Bilateral Maxillary Lateral Incisor Agenesis Patient using Miniplates.

AIM: This case report aimed to present an orthodontic mechanic alternative for space opening in a patient missing maxillary lateral incisors, using miniplates as anchorage, associated with self-ligating brackets. BACKGROUND: Dental agenesis affects the population causing esthetic and functional damages. The prevalence of missing maxillary lateral incisors should be considered for its significant rate and negative impact on smile esthetics. CASE REPORT: This treatment was chosen based on the presence of balanced facial pattern, large canine anatomy, the need to improve dental occlusion to prevent further wear, and patient's esthetic complaint. To obtain the results, upper third molars were extracted, and two miniplates were installed to distalize the upper arch with no need for patient compliance or auxiliary devices. Self-ligating brackets were used to reduce friction on posterior teeth, thus facilitating movement with light force application. At the end of 19 months, the patient presented with class I good overbite and overjet, and adequate space for implant and prosthetics; also, good facial esthetic was maintained. CONCLUSION: When indicated, space opening may provide excellent esthetics and functional results, and even more predictable results when skeletal anchorage miniplates are used to distalize all posterior teeth. CLINICAL SIGNIFICANCE: Considering the high level of esthetic and functional compromise caused by dental agenesis, the technique hereby described represents a viable mechanic alternative within orthodontic possibilities.