Evaluation of the effects of asymmetry monoblog on craniofacial and dentoalveolar structures

Aim: The aim of this study is to examine the craniofacial and dentoalveolar changes in patients with mandibular transverse asymmetry by correcting their asymmetries using an asymmetry monoblock. Materials and Methods: The models and lateral cephalometric films of 66 individuals with an average age of 14.18±1.7 years, who underwent mandibular skeletal asymmetry correction with an asymmetry monoblock, were evaluated at the beginning and end of treatment. For 36 of these individuals with available posteroanterior cephalometric films, transverse and vertical measurements were taken on their radiographs at the start (T0) and end (T1) of treatment, and right-left symmetry was assessed. Sagittal and vertical measurements were performed on the lateral cephalometric radiographs at T0 and T1 for all 66 individuals. All T0 and T1 models of the 66 individuals were scanned with the 3Shape R700™. Measurements of intercanine, intermolar distances, arch depth, arch circumference in both upper and lower jaws, and changes in maxillary canine tooth inclination were examined. These parameters were measured using OrthoAnalyzer software. Dolphin Imaging software was used to compare the craniofacial changes in T0 and T1 differences in posteroanterior and lateral cephalometric radiographs. Results: In patients treated with functional orthopedic therapy using an asymmetry monoblock, model analyses after treatment revealed a significant increase in dentoalveolar maxillary measurements, while no change was observed in mandibular measurements. In the asymmetry monoblock, a more pronounced increase was observed between the upper first molar and the midline on the side with the expansion screw. In posteroanterior cephalometric measurements, it was noted that the ANSMeMSR° measurement approached zero degrees by the end of treatment, while there was a significant increase in the CoL-AG measurement in the group with a left deviation. No significant change was observed in the other posteroanterior cephalometric measurements. In lateral cephalometric measurements, a decrease in the ANB° angle, an increase in the SNB° angle, and increases in vertical angles (FMA° and Sn/GoGn°) were observed. No significant change was noted in the other lateral cephalometric measurements. In the difference measurements of the mandibular midline between the start (T0) and end (T1) of treatment, midline correction was found to be 2.68 mm (±0.89) in the left-deviated group and 2.6 mm (±0.93) in the right-deviated group. These changes were found to be statistically significant. Conclusions: In functional orthopedic treatment with an asymmetry monoblock during the growth and development period, mild mandibular asymmetries were largely corrected. It has been demonstrated that functional orthopedic treatment with an asymmetry monoblock is a good alternative to orthognathic surgery and camouflage treatment for patients with mild mandibular asymmetry. Keywords: Mandibular asymmetry, asymmetry monoblock, functional orthopedic treatment