Use of direct miniplate anchorage in conjugation with Forsus Fatigue Resistant device in class II growing females: a randomized controlled trial

Abstract

Objective: The current randomized clinical trial aimed toevaluate the use of direct miniplates anchorage in conjunction with the Forsus Fatigue Resistant Device (FFRD) in treatment of skeletal Class II malocclusion. Material and Methods:48 Class II femaleswere randomly allocated to either the conventional Forsus (FFRD) group (16 patients, mean age 12.1±0.9years) Forsus with miniplates (FMP) group (16 patients, mean age 12.5±0.9 years), or untreated control group (16 subjects, mean age 12.1±0.9 years). After the leveling and alignment stage, miniplates were inserted in the mandibular symphysis in the FMP group. FFRD was inserted directly on the miniplates in the FMP and onto the lower wire in the FFRD group. The appliance was removed after reaching an edge to edge incisor relationship. Results: The effective mandibular length significantly increased in the FMP group only (4.05±0.78).no significant differences were found in the maxillary dimensions. The upper incisors retroclined in the FFRD and FMP groups with no difference between them. The lower incisors showed a significant proclination in the FFRD group (9.17±2.42) and non-significant retroclination in the FMP group. Soft tissue parameters were improved in both treatment groups. Conclusion: The use of miniplates with the FFRD was successful in increasing the effective mandibular length in Class II malocclusion subjects in the short term. The unfavorable proclination of the lower incisors was evident with the conventional FFRD but was successfully eliminated with the miniplates anchorage. 19 Volume 54 – December 2018 Egyptian Orthodontic Journal Registration: This trial was registered at ClinicalTrials.gov with an identifier number: NCT02475785. Clinical Relevance: The current trial proved the efficiency of the use of miniplates anchorage with FFRD in enhancement the skeletal outcomes of Class II treatment. The technique is advocated for use in Class II subjects having pre-treatment proclined lower incisors. INTRODUCTION Scientific background and explanation of rationale: Mandibular retrusion was reported to be the most common characteristic of Skeletal Class II malocclusion . Class II profile attractiveness was previously investigated in the literature. It was found that patients, laypersons, orthodontists and oral surgeons, rated subjects with Class II profiles as nonattractive . Fixed functional appliances (FFA) are considered an attractive alternative over removable functional appliances (RFA) for treatment of Class II malocclusion in growing children; where the factor of patient cooperation is controlled. The Forsus Fatigue Resistant Device (FFRD), (3M Unitek Corp, Monrovia, Calif), is a semi-rigid FFA that was reported to be efficient and well-accepted by the patients. Recently, systematic reviews concluded that the skeletal effects of RFAs and FFAs could be considered of negligible clinical importance. This could be attributed to the anchorage loss accompanied by these appliances that could compromise the skeletal correction . Several attempts were proposed to counteract the unwanted dento-alveolar side effects of FF As including the use of skeletal anchorage. Studies proved that miniscrew anchorage reduced the lower incisors proclination but were not able to achieve significant skeletal mandibular effects. Titanium miniplates were introduced for the use in orthodontics in 1999 for open bite correction. They were proven to be well accepted by patients and providers and became popularin various applications. Recently, they were used for the direct loading of FFRD for correction of skeletal Class II malocclusion but the available studies were either retrospective, non-controlledor non-randomized. Cone Beam Computed Tomography (CBCT) has an advantage of improved visualization over the conventional two dimensional (2D) imaging techniques. Shortcomings of 2D radiographic techniques were thoroughly mentioned in the literature. Errors in landmark identification, visualization and the superimposition of bilateral structures in the 2D cephalograms could compromise the accuracy of their use in research studies. Thus, CBCT was chosen as a radiographic imaging tool to evaluate the treatment effects. Specific objectives or hypotheses: This study aimed to compare the dental and skeletal effects of the use of FFRD alone or in conjunction with direct miniplates anchorage in treatment of skeletal Class II malocclusion as compared to an untreated Skeletal Class II control group. The tested null hypothesis was that the use of direct miniplates anchorage with FFRD would have no additional skeletal effects. MATERIAL AND METHODS Trial design and any changes after trial commencement This was a parallel-group, randomized, controlled trial with a 1:1:1 allocation ratio. The trial was registered at ClinicalTrials.gov with an identifier number: NCT02475785. 20 Volume 54 – December 2018 Egyptian Orthodontic Journal Participants, eligibility criteria, and settings: The participants were recruited at the Faculty of Dentistry, Cairo University outpatient orthodontic clinic. The study was self-funded by the authors who were part of the University staff. All the study participants were informed about the procedures and multiple radiation exposures. The sample comprised 48 female subjects. The inclusion criteria for the participants were as follows: • Chronologically; the patients were 10-13 years of age. • Skeletally, the patients had to be in the cervical maturational stage 3 as detected by the lateral cephalometric radiograph. • Skeletal Angle Class II malocclusion with a deficient mandible. (SNB≤76°) and a horizontal or neutral growth pattern. (MP/SN ≤ 39°) • Class II division 1 incisor relation. • Increased over jet (min 5 mm) • Class II canine relationship. (minimum of half unit) • Mandibular arch crowding less than 3 mm..