抄録
The purpose of this retrospective study was to examine borderline cases between surgical orthodontic treatment and orthodontic treatment with the Index of Orthognathic Functional Treatment Need （IOFTN）. The subjects were 184 patients who underwent surgical orthodontic treatment or orthodontic treatment without orthognathic surgery in our hospital （Niigata University Medical and Dental Hospital） during the period from January 2015 to December 2017. The subjects were divided into three groups: the surgical orthodontic treatment group （SO group） consisted of 92 patients （29 males and 63 females, mean age ± SD: 24 ± 8 years）. The skeletal anchorage system group （SA group） consisted of 41 patients （13 males and 28 females, mean age ± SD: 26 ± 8 years） treated by orthodontic treatment combined with skeletal anchorage. The conventional orthodontic treatment group （CO group） consisted of 51 patients （19 males and 32 females, mean age ± SD: 23 ± 8 years）. In the SO group, a combination of Le Fort I osteotomy and bilateral sagittal split osteotomy was used in 62 cases （67.4％）, bilateral sagittal split osteotomy in 20 cases （21.7％）, a combination of multi-segmental Le Fort I osteotomy and bilateral sagittal split osteotomy in six cases （6.5％）, and other techniques were used in four cases （4.4％）. In the SA group, orthodontic anchor screws and orthodontic anchor plates were used in 33 cases and eight cases, respectively. The ANB angle was measured to classify the skeletal pattern as follows: Class 1 （1 ≤ ANB ≤ 4）, Class 2 （ANB > 4）, and Class 3 （ANB < 1）.
The results showed that Class 3 accounted for 57.6％ of the cases in the SO group and Class 2 accounted for 48.8％ of the cases in the SA group, and most of the cases in the CO group were Class 1 and 2. In the SA and CO groups, some cases with maxillary protrusion and/or mandibular retrusion were treated by only orthodontic treatment, even if surgical orthodontic treatment was indicated for those cases based on IOFTN. These results suggest that cases with maxillary protrusion or/and mandibular retrognathia might be borderline between surgical orthodontic treatment and orthodontic treatment.
