The effect of non-extraction treatment on the dimensions of mandibular symphysis in patients with class I malocclusion

Öz

OBJECTIVE: The aim of this retrospective study was to evaluate the short- and long-term effects of mandibular incisor movement due to non-extraction treatment on dimensions of mandibular symphysis (MS).

MATERIALS AND METHOD: Lateral cephalograms (before treatment, TB; after treatment, TS; retention, P) of 20 females classified as skeletal class 1 (ANB:0-4°), dental class I and having an optimal vertical growth direction (SN/GoGN: 32±6°) were selected from the archive of the Department of Orthodontics, Faculty of Dentistry, Gazi University. These subjects had mean chronological age of 14.9±3.3 years and mean mandibular crowding of 2.6±1.7 mm. On the cephalograms, 7 angular, 11 linear measurements were done in order to determine skeletal characteristics, position of the mandibular incisor and dimensions of MS. The width of MS and the amount of bone around the mandibular incisor were determined at three levels (crest ridge, center of rotation and root apex of the incisor). Statistical analyses were performed by using One-Way ANOVA to evaluate intergroup differences followed by a post-hoc Tukey test. Correlation analyses were performed by using Pearson correlation test (p<0.05).

RESULTS: Mandibular incisor protruded significantly with treatment (Co/1°, 1/MP°: p<0.05; 1/NB°, 1-NB: p<0.01) and bone thickness at crest ridge level was significantly lower at TS (p<0.05) and at P (p<0.001) when compared to TB. However, bone thickness at the center of rotation and root apex, and the MS height were not affected from treatment (p>0.05). There were no correlations between age at TB, total treatment time, amount of crowding and mandibular incisor protrusion with changes in crest ridge bone thickness (p>0.05).

CONCLUSION: The mandibular incisor protrusion seen after non-extraction treatment caused a decrease in bone thickness at the crest ridge level, and it was maintained at the retention period.

Anahtar Kelimeler

• Malocclusion,Angle class I,mandibular symphysis,orthodontics

Sınıf I maloklüzyona sahip bireylerde çekimsiz sabit ortodontik tedavinin mandibular simfiz boyutları üzerine etkisinin değerlendirilmesi

Öz

AMAÇ: Bu retrospektif çalışmanın amacı çekimsiz sabit tedavi ile meydana gelen alt kesici diş hareketinin, mandibular simfiz (MS) boyutlarına kısa ve uzun dönemdeki etkilerini araştırmaktır.

GEREÇ VE YÖNTEM: Gazi Üniversitesi Diş Hekimliği Fakültesi, Ortodonti Anabilim Dalı arşivinde bulunan hasta kayıtları arasından, iskeletsel sınıf 1 (ANB:0-4°), dişsel Sınıf I, optimal büyüme yönü gösteren (SN/GoGN: 32±6°), ortalama yaşları 14.9±3.3 yıl ve alt çenedeki ortalama çapraşıklık miktarı 2.6±1.7 mm olan 20 kız bireyin tedavi başı (TB), tedavi sonu (TS) ve pekiştirme dönemi (P) lateral sefalometrik filmleri değerlendirildi. Sefalometrik filmler üzerinde iskeletsel yapılar, alt kesici dişin pozisyonu ve MS boyutlarına

ilişkin 7 açısal 11 doğrusal ölçüm yapıldı. MS genişliği ve dişi çevreleyen kemik miktarı üç seviyede (kret tepesi, alt kesici dişin rotasyon merkezi ve kök apeksi) tespit edildi. TB, TS ve P dönemlerine ait ölçümler arasında ortalamalar yönünden farkın önemliliği tek yönlü ANOVA testi ile, farka neden olan gruplar Tukey post-hoc testi ile, korelasyonlar ise Pearson korelasyon testi kullanılarak araştırıldı (p<0.05).

BULGULAR: Alt kesici dişlerin tedavi ile protrüze olduğu (Co/1°, 1/MP°: p<0.05; 1/NB°, 1-NB: p<0.01); kret tepesindeki kemik miktarının TS (p<0.05) ve P (p<0.001) döneminde TB’ye göre anlamlı olarak azaldığı görüldü. Ancak rotasyon merkezi ve apeks seviyesindeki kemik miktarları ile simfiz yüksekliğinin tedaviden etkilenmediği görüldü (p>0.05). Hastanın TB yaşı, tedavi süresi, TB çapraşıklık miktarı ve alt kesici dişin protrüzyon miktarının, kret seviyesindeki kemiğin değişimiyle bir etkileşimi bulunmadı (p>0.05).

SONUÇ: Çekimsiz ortodontik tedaviyle görülen alt kesici diş protrüzyonu, kret seviyesindeki alveol kemik kalınlığının azalmasına neden olmuştur ve pekiştirme döneminde bu değişim korunmuştur.

Anahtar Kelimeler

• Maloklüzyon,mandibular simfiz,ortodonti,Angle sınıf I

Kaynakça

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