Effects of clear aligners on the vertical position of the molar teeth and the vertical and sagittal relationships of the face: a preliminary retrospective before-after clinical trial.

INTRODUCTION: Despite the popularity of clear aligners, their predictability has not been assessed adequately. Moreover, no study has investigated their effects on numerous dentomaxillary variables. Therefore, this study was conducted for the first time, assessing several new or controversial items. The aim of the study was to evaluate the effects of clear aligners on the vertical position of the molar teeth and the vertical and sagittal relationships of the face. METHODS: This preliminary retrospective before-after non-randomized clinical trial was performed on 168 observations of 84 patients (33.60±9.28 years, 54 females) treated with 0.75mm Invisalign appliances. Pretreatment and posttreatment values were measured for: mandibular plane angle, occlusal plane angle, Y-Axis, ANB, facial angle, lower anterior facial height, overbite, and the distances of the molars from the palate and mandibular plane were measured. The alterations in parameters caused by treatment (delta values) were calculated for each measurement. Effects of treatment and some parameters on delta values were analyzed statistically (α=0.05). RESULTS: Mean±SD of ΔMP-FH, ΔOP-FH, ΔY-Axis, ΔLAFH, ΔNPog-FH, ΔANB, ΔOverbite, ΔSNB, Δ6-PP, Δ7-PP, Δ6-MP, and Δ7-MP were respectively 0.11±1.61, 0.80±1.56, 0.15±1.18, 0.07±0.91, -0.22±1.25, 0.03±0.62, 0.04±1.15, -0.06±1.14, -0.36±0.94, -0.32±1.14, 0.19±0.96, 0.18±1.10. Only the alterations in OP-FH, 6-PP, and 7-PP were significant (P≤0.011). Age, sex, treatment duration, or pretreatment mandibular plane angle were not correlated with any delta values. However, the pretreatment occlusal plane angle was negatively correlated with ΔOP-FH and ΔY-Axis. Crowding was correlated negatively with ΔOP-FH and ΔY-Axis and positively with ΔNPog-FH. Overjet was negatively correlated with ΔANB and ΔOverbite (P≤0.035). CONCLUSIONS: Invisalign intruded first/second maxillary molars and increased the occlusal plane angle. Age, sex, and treatment duration were not correlated with post-treatment anatomic alterations.

Knowledge and beliefs regarding temporomandibular disorders among orthodontists.

INTRODUCTION: This project was undertaken to accomplish 2 objectives: (1) to identify whether there is a discrepancy between orthodontists and experts in temporomandibular disorders (TMD) related to diagnosis and treatment of TMD patients, and (2) to influence the manner in which TMD curricula are taught in orthodontic residency programs, better preparing future orthodontic specialists to diagnose and treat (and refer) patients with TMD. METHODS: A survey invitation was e-mailed to 8870 members of the American Association of Orthodontists. Items were answered on a 6-point scale (0 = I don't know; 1 = strongly disagree; 2 = disagree; 3 = neutral; 4 = agree; 5 = strongly agree). A group consensus was attributed when more than 50% of the orthodontists supported a response. Previously published responses of TMD experts were used as a reference to evaluate the orthodontists' responses. Comparisons between the responses from the 2 groups were assessed using a z-test. RESULTS: Among the participants who responded to the questionnaire, 148 were residents, 1132 were private practitioners, and 61 were full-time faculty. Sixty-two percent of the participants did not think they received enough training in TMD during their orthodontic residency. Although 62% of participants indicated that they feel comfortable diagnosing TMD patients, 50.2% do not feel comfortable treating TMD patients. There was no significant difference between the 2 groups' responses under one-third of the questions. CONCLUSIONS: It is clear that orthodontic residencies in the U.S. need to improve methods of teaching TMD concepts. Although most orthodontists feel comfortable diagnosing TMD patients, less than half feel comfortable treating those patients, and the difference in responses with the TMD expert group was significant in 71% of the questions.

Comparison of pain perception during miniscrew placement in orthodontic patients with a visual analog scale survey between compound topical and needle-injected anesthetics: A crossover, prospective, randomized clinical trial.

INTRODUCTION: The use of a compound topical anesthetic (CTA) instead of an injection of a local anesthetic for placing miniscrew implants offers advantages to both the clinician and the patient. The purpose of this crossover, prospective, randomized clinical trial was to compare the clinical effectiveness of a CTA with that of a needle injection of local anesthetic for miniscrew placement. METHODS: Twenty-four orthodontic patients in a university clinic were recruited; they required bilateral buccal miniscrews for orthodontic anchorage. Eligibility criteria included healthy patients with no special needs; over 8 years of age and 25 pounds; not taking sulfonamides, monoamine oxidase inhibitors, tricyclic antidepressants, or phenothiazines; and not allergic to ester-type local anesthetics or any of the other materials used in the study. A computer generated a randomization list. The allocation was randomized by anesthetic protocol and side of the mouth, and was restricted to achieve balance by treatment and side of the mouth. No allocation concealment was applied. Associated with each randomized number was the subjects' assignment into 1 of 4 groups divided by the side of first miniscrew placement and the type of anesthetic. Blinding was done only for data analysis because of clinical limitations. Each patient received a CTA on one side and an injection of anesthetic on the other before miniscrew placement in a crossover study design. The outcome was assessed by measuring pain levels with a 100-mm visual analog scale at 5 time points. Anesthetic failures occurred when the miniscrew could not be fully comfortably placed with a given anesthetic. Data were organized by visual analog scale time points, and descriptive statistics were calculated. A factorial repeated-measures analysis of variance was used to determine any differences. RESULTS: Twenty-seven patients were assessed for eligibility, and 24 agreed to participate in the study. Patients did not distinguish any differences in pain between the application of the CTA and the injection before or during anesthetic placement, but they experienced more pain with the CTA during miniscrew placement. The mean difference for the entire procedure between the 2 anesthesia types was 24.6 units, and the 95% confidence interval was 18.8 to 30.4, a statistically significant finding (P = 0.0002). The CTA was still viewed as more painful 1 month after the procedures. Significantly more anesthetic failures occurred with the CTA (41.6%) than with the injection (0%). No serious harm was observed in any patient; when significant pain was observed with the CTA, a needle injection of local anesthetic was administered. CONCLUSIONS: CTAs provided less predictable, often inadequate, and less comfortable anesthesia than an injection of a local anesthetic for managing patient discomfort during miniscrew placement in buccal sites. REGISTRATION: This trial was not registered. PROTOCOL: The protocol was determined and approved by the research committee and institutional review board before the trial. FUNDING: No external funding was used other than the donation of the miniscrews from Rocky Mountain Orthodontics, and no conflict of interest was declared.