To elucidate genetic factors affecting orthodontic treatment duration, we employed targeted next-generation sequencing on DNA from the saliva of 117 patients undergoing orthodontic treatment after premolar extraction. The clinical characteristics of patients are summarized, and the association of clinical variables with treatment duration was assessed. Patients whose treatment duration deviated from the average were classified into an extreme long group or an extreme short group. We identified nine single nucleotide polymorphisms (SNPs) of six genes that significantly differed in the two groups via targeted sequencing. The frequency of the CC genotypes of WNT3A, SPP1 (rs4754, rs9138), and TNFSF11, TT genotype of SPP1 (rs1126616), and GG genotype of SFRP2 was significantly higher in the extreme long group than in the short group. In the extreme short group, the TC genotype of SPP1, AA genotype of P2RX7, CT genotype of TNFSF11, and AG genotype of TNFRSF11A tended to exhibit higher frequency than in the long group. Taken together, we identified genetic polymorphisms related to treatment duration in Korean orthodontic patients undergoing premolar extraction. Our findings could lead to further studies predicting the prolongation of the orthodontic treatment duration, and will be of great aid to patients as well as orthodontists.

To elucidate genetic factors affecting orthodontic treatment duration, we employed targeted next-generation sequencing on DNA from the saliva of 117 patients undergoing orthodontic treatment after premolar extraction. The clinical characteristics of patients were summarized, and the association of clinical variables with treatment duration was assessed. Patients whose treatment duration deviated from the average were classified into an extreme long group or an extreme short group. We identified single nucleotide polymorphisms (SNPs) significantly enriched in the two groups via targeted sequencing. Nine SNPs (six genes) were significantly enriched in both groups. In the extreme long group, the frequency of the CC genotypes of WNT3A, SPP1 (rs4754, rs9138), and TNFSF11, the TT genotype of SPP1 (rs1126616), as well as the GG genotype of SFRP2 was significantly higher than in the short group. In the extreme short group, the TC genotype of SPP1, the AA genotype of P2RX7, the CT genotype of TNFSF11, and the AG genotype of TNFRSF11A tended to exhibit higher frequency than in the long group. Taken together, we identified genetic polymorphisms related to treatment duration in Korean orthodontic patients undergoing premolar extraction. Accurate prediction of the treatment period through further research will be of great aid to patients as well as orthodontists.