Pengaruh Pencabutan Premolar Terhadap Overall Bolton Ratio Pada Maloklusi Klas III di RSGMP FKG USU

Abstract

Aim of study: Tooth extraction was a treatment of choice in the tooth size discrepancy cases to achieve appropriate allignment, angulation and inclination of the teeth. The objective of this study was to determine the effect of premolar extraction on overall Bolton ratio in Class III malocclusion. Materials and method: Samples in this study consisted of 40 subjects with Class III malocclusion in accordance with the inclusion criteria. Measurements performed directly on 12 maxillary and mandibular teeth by using an electronic digital caliper with accuracy up to 0.01 mm on the study model. Furthermore, the initial overall Bolton ratio was calculated on the whole samples and continued with several hypothetical extractions. After that, the calculation of the overall Bolton ratio in the fifth combination of premolar ectraction was done and the results were statistically tested to see the effect of the premolar extraction on overall Bolton ratio in Class III malocclusion. Results: The initial overall Bolton ratio consisted of small overall Bolton ratio (88.94 ± 0.38) the number of 5 subjects (12.5%), normal overall Bolton ratio (91.15 ± 1.07) with the number of 24 subjects (60% ) and large overall Bolton ratio (94.56 ± 0.91) with the number of 11 subjects (27.5%). Wilcoxon test showed the effect of premolar tooth extractions on overall Bolton ratio in Class III malocclusion (p=0.001). Overall Bolton ratio decreased significantly after the extraction of the premolars in all hypothetical extractions, where normal Bolton ratio were observed in the combination of upper first premolar and lower second premolar extractions. Conclusion: Premolar tooth extraction affects the overall Bolton ratio in Class III malocclusion.

Latar Belakang: Pencabutan gigi merupakan salah satu pilihan perawatan pada kasus diskrepansi ukuran gigi untuk mendapatkan kesejajaran, angulasi dan inklinasi gigi yang sesuai. Tujuan penelitian ini adalah untuk mengetahui pengaruh pencabutan premolar terhadap overall Bolton ratio pada maloklusi Klas III di RSGMP FKG USU. Bahan dan Cara: Sampel pada penelitian ini berjumlah 40 subjek dengan maloklusi Klas III (ANB=-1,7±0,91º) yang sesuai dengan kriteria inklusi. Pengukuran dilakukan langsung pada 12 gigi rahang atas dan bawah dengan menggunakan kaliper digital elektronik dengan keakuratan sampai 0,01 mm pada studi model. Selanjutnya, dilakukan perhitungan overall Bolton ratio awal pada seluruh sampel dan dilanjutkan dengan melakukan kombinasi pencabutan (hypothetical extraction). Setelah itu, dilakukan perhitungan overall Bolton ratio pada kelima hypothetical extraction dan hasilnya diuji secara statistik untuk melihat pengaruh pencabutan gigi premolar terhadap overall Bolton ratio pada maloklusi Klas III. Hasil: Overall Bolton ratio awal pasien terdiri dari overall Bolton ratio kecil (88,94 ± 0,38) berjumlah 5 subjek (12,5%), overall Bolton ratio normal (91,15 ± 1,07) dengan jumlah 24 subjek (60%) dan overall Bolton ratio besar (94,56 ± 0,91) dengan jumlah 11 subjek (27,5%). Uji Wilcoxon menunjukkan adanya pengaruh pencabutan gigi premolar terhadap overall Bolton ratio pada maloklusi Klas III (p=0,001). Overall Bolton ratio mengalami penurunan yang signifikan setelah dilakukan pencabutan premolar pada semua hypothetical extraction, dimana rasio Bolton normal terbanyak ditemukan pada hypothetical extraction gigi premolar pertama rahang atas dan premolar kedua rahang bawah. Kesimpulan: Pencabutan gigi premolar mempunyai pengaruh pada overall Bolton ratio pada maloklusi Klas III.