Evaluation of the results of controlled extraction of permanent first molars via cephalometric analysis

SUMMARY Evaluation of the Results of Controlled Extraction of Permanent First Molars via Cephalometric Analysis The aim of this retrospective study is to clinically and radiologically evaluate changes in cephalometric parameters (SNA, SNB, ANB, SNGoGn, Max1-NA, Mand1-NB, IMPA, and Interincisal Angle), as well as Overjet and Overbite measurements, dimensional changes in the extraction space, movements of adjacent teeth, and deviations in the dental midline in children who underwent unilateral or bilateral extraction of permanent first molars for various reasons over a 20-month period. The study included patients with at least one unilateral or bilateral extraction of upper or lower permanent first molars, where the second molar was at stage 7 according to Nolla's classification at the time of extraction, and all permanent third molar buds were radiographically visible. Only patients with normal dental molar occlusion and facial profiles were included based on clinical and radiographic criteria. The patients were recalled for clinical evaluation at approximately 20 months post-extraction, and radiographic assessments were conducted using panoramic and cephalometric radiographs. Measurements from cephalometric films were analyzed using Dolphin Software. At the end of the 20-month follow-up period, changes in cephalometric angles and Overjet and Overbite values were compared to baseline measurements. Panoramic radiographs were analyzed to determine the extent of extraction space closure and dental midline deviations. The extent of extraction space closure was calculated by measuring the distance between the mesial point of the second permanent molar and the distal point of the second permanent premolar. Deviations in the dental midline were assessed using the Levandovski method with the maxillary midline as a reference. Intraoral images were used to assess lingual or palatal tipping in the second permanent molars and rotations in the second molars and premolars, which were evaluated based on arch shape. Dimensional measurements of the extraction spaces and angular measurements of adjacent teeth were conducted using AutoCAD® software applied to panoramic radiographs. Changes in the dimensional characteristics of extraction spaces, rotations of adjacent teeth, and dental midline deviations were analyzed for each jaw, and differences between the upper and lower jaws were thoroughly assessed. Additionally, the potential impact of unilateral versus bilateral extractions on adjacent teeth was investigated. Statistical analyses were performed, with significance set at p<0.05. During the follow-up period, a significant increase in the SNA angle and a significant decrease in the SNGoGn angle were observed (p<0.05). Additionally, statistically significant increases in Overbite and Overjet values were noted (p<0.05). The study also revealed significant dimensional changes in the extraction spaces across all jaws compared to baseline values (p<0.05). The findings demonstrated that extractions in the upper jaw were more successful in terms of spontaneous space closure. By the end of the follow-up period, the success rate for spontaneous closure was 58.3% in the upper jaw and 31.25% in the lower jaw, highlighting the need for prolonged and meticulous follow-up for lower jaw extractions. The results of the study showed a decrease in vertical direction angles and an increase in Overbite and Overjet values in patients who underwent permanent first molar extractions. It was particularly recommended that permanent first molar extractions should only be performed in necessary cases for patients with existing deep bite (deepbite) issues. Unilateral or bilateral extractions were found to have no significant impact on the rotation or lingual/palatal tipping of adjacent teeth. However, most adjacent teeth exhibited rotational movements, and lingual tipping was common in second molars near the extraction site. These findings emphasize the importance of careful follow-up planning by the clinician and the ability to intervene promptly if necessary. In conclusion, orthodontic treatment may be required following permanent first molar extractions, and such decisions should be planned within a multidisciplinary framework. Keywords: molar tooth, tooth extraction, cephalometric analysis