Is motor-driven insertion of orthodontic miniscrews more advantageous than manual insertion? A micro-CT evaluation of bone miniscrew contact surface area and cortical microcracks in rabbits.

AIM: This in vitro study aimed to evaluate and compare the bone-miniscrew contact surface area (BMC) and the cortical bone microcracks (CM) resulting from manual (hand-driven) and automated (motor-driven) orthodontic miniscrew (OM) insertion methods. METHODS: Thirty-three OM were inserted in the femurs of nine New Zealand rabbits using manual (n = 16) and automated (n = 17) insertions. After euthanizing the rabbits, bone blocks, each including one OM, were sawed. Micro-CT scanning was performed, and data analysis included reconstruction, binarization and quantification of morphometric parameters of BMC and the number and length of CM. Means and standard deviations for complete BMC, complete BMC proportion, cortical BMC, cortical BMC proportion, and length and number of CM were calculated. Mixed model analysis was used to adjust for more than one sample/CM per animal. A paired t-test was used to compare the number of CM between the two groups. RESULTS: Compared to the automated insertion, manually inserted miniscrews had significantly lower complete BMC (7.54 ± 1.80 mm2 vs. 11.99 ± 3.64 mm2), cortical BMC (5.91 ± 1.48 mm2 vs. 8.48 ± 1.90 mm2) and cortical BMC proportion (79.44 ± 5.84% vs. 87.94 ± 3.66%). However, it was not statistically significant in complete BMC proportion (p = .052). The automated insertion also resulted in a significantly lower mean number of CM than the manual method (p = .012). However, the length of the cracks was shorter in the manual group but with no significant difference (p = 0.256). CONCLUSION: Motor-driven OM insertion results in superior BMC and reduction in the number of CM, which may lead to better miniscrew stability.

Adult Perceptions of Different Orthodontic Appliances.

Introduction: Pursuing an esthetically-pleasing orthodontic outcome, orthodontic patients must consider and choose from the different available options of orthodontic appliance. Practitioners need to be better informed of their customers' preferences to make better practice management decisions and satisfy their patients' needs. PURPOSE: To explore adult laypeople's perceptions of the attractiveness, acceptability, preference and economic value of different orthodontic appliances when they consider these appliances for themselves and for their children. PATIENTS AND METHODS: This cross-sectional survey included 199 adults (110 females). The average age of participants was 27.7 years. Participants answered a questionnaire evaluating and comparing multiple smiling images of an adult wearing different orthodontic appliances. Participants rated each appliance for: (1) attractiveness on a Likert scale; (2) acceptability of having the appliance placed for themselves and their children (with a yes/no response); (3) preference (by ranking all appliances in order); and (4) economic value (by providing the additional amount they are willing to pay for each appliance for themselves and their children). RESULTS: We found a statistically significant difference in the attractiveness scores between the different orthodontic appliances (p< 0.0001). The most attractive appliances were clear aligners and lingual brackets. The least attractive appliances were colored o-tied-brackets followed by shaped-brackets. Clear aligners were the most acceptable appliances among our participants to have placed on themselves (86.9%) and their children (84.9%). Shaped brackets were the least acceptable appliances among our participants to have placed on themselves (24.1%) and their children (36.2%). The most preferred appliances were lingual brackets (39.2%), followed by clear aligners (34.17%). The least preferred appliances were colored o-tied-brackets (4%). Participants varied with regards to how much more they were willing to pay for each of the different orthodontic appliances. The majority were willing to pay more for clear aligners and lingual brackets to have them placed on themselves but not to have them placed on their children. CONCLUSION: Adults preferred more innovative esthetic appliances over traditional ones and were willing to pay more to have them placed on themselves but not on their children.

Space planning sensitivity and specificity: Royal London Space Planning and Korkhaus Analyses.

OBJECTIVES: To establish the sensitivity and specificity of the Korkhaus and Royal London Space Planning Analyses. METHODS: The sample consisted of 30 cases with two sets of study models and lateral cephalometric radiographs taken at least three years apart. These were then further subdivided into Class I (N = 10), Class II division 1 (N = 10) and Class II division 2 cases (N = 10). The Royal London Space Planning Analysis and the Korkhaus Analysis were applied on these cases at both times. RESULTS: Study model analysis: The Royal London Planning Analysis revealed that in Class I malocclusions, upper and lower arch crowding and spacing changed significantly with time. The total space required and tooth size reduction for the lower arch had also changed significantly. Additionally, in the Class II division 1 malocclusions, lower arch crowding and spacing, total space required and the need for tooth size reduction had significantly increased, while in Class II division 2 malocclusions, a statistically significant increase was observed in the upper and lower arch crowding and spacing. The Korkhaus Analysis showed that in Class I malocclusions, a significant decrease was observed in the lower arch length and the lower anterior arch width. The upper posterior (inter-molar) arch width had significantly increased. In Class II division 1 malocclusions the lower right posterior space available had decreased significantly. The upper posterior arch width and the lower posterior arch width also significantly increased. In Class II division 2 malocclusions, a statistically significant decrease was observed in the lower anterior arch length. There were no significant changes in all angular and the two linear measurements for all classes. CONCLUSIONS: The Royal London Space Planning Analysis and the Korkhause Analysis are clinically sensitive analyses. The Royal London Space Planning Analysis lacks specificity to be a robust model for treatment planning; modification may be required before this technique is accepted.