【摘要】：目的:研究在人工老化的條件下,不同形態(tài)的牙本質(zhì)肩領與樁核系統(tǒng)對樁核冠修復后的牙體抗折性能的影響。方法:收集三個月內(nèi)因正畸治療拔除的下頜單根管第一前磨牙64顆,隨機分成8組(n=8),各組離體牙預備成不同的牙體缺損形態(tài),設計為不同的牙本質(zhì)肩領及樁核類型。A1組:360°牙本質(zhì)肩領+玻璃纖維樁樹脂核。A2組:360°牙本質(zhì)肩領+鑄造鈷鉻合金樁核。B1組:180°頰側(cè)牙本質(zhì)肩領+玻璃纖維樁樹脂核。B2組:180°頰側(cè)牙本質(zhì)肩領+鑄造鈷鉻合金樁核。C1組:180°舌側(cè)牙本質(zhì)肩領+玻璃纖維樹脂樁核。C2組:180°舌側(cè)牙本質(zhì)肩領+鑄造鈷鉻合金樁核。D1:180°頰、舌側(cè)牙本質(zhì)肩領+玻璃纖維樁樹脂核。D2:180°頰、舌側(cè)牙本質(zhì)肩領+鑄造鈷鉻合金樁核。牙本質(zhì)肩領高度均設為2mm,厚度設為(1.2±0.2)mm。樁核粘接就位后所有離體牙均按照全冠預備標準進行鈷鉻合金鑄造金屬全冠修復。將8組樣本全部進行冷熱循環(huán)(5℃-55℃)處理5000次。在電子萬能試驗機上以與牙長軸成150°于頰尖頂處加載,加載速度設置為1.0mm/min,直至試件任何一處出現(xiàn)斷裂,對各組折裂強度進行方差分析、t檢驗統(tǒng)計分析;觀察折裂模式的區(qū)別,并進行卡方檢驗(α=0.05)。結果:1各組試驗牙齒的牙根長度、釉牙骨質(zhì)界處近遠中徑、頰舌徑均無統(tǒng)計學上的差異(P0.1)。2纖維樁樹脂核組及鑄造金屬樁核組抗折強度最高值都出現(xiàn)在360°環(huán)形組,統(tǒng)計結果顯示與其他組間存在明顯差異(P0.05)。其余各組間未見明顯差異。3鑄造金屬樁核組的抗折強度高于纖維樁樹脂核組,但在保留舌側(cè)肩領類型組的差異無意義,其余三組間差異均有統(tǒng)計學意義(P0.05)。4纖維樁核組可修復性折裂例數(shù)明顯高于鑄造金屬樁核組�？ǚ綑z驗顯示差異具有統(tǒng)計學意義(P0.05)。結論:1牙本質(zhì)肩領的完整性對樁核冠修復后牙體抗折性起著決定性作用,因此臨床上應盡量多地保留牙本質(zhì)肩領來提高修復后牙體的抗折性能,牙本質(zhì)肩領位置形態(tài)對牙體抗折性能的影響較小。2鑄造金屬樁核抗折強度高,但易造成牙體的不可修復性根折,纖維樁核雖抗折強度較低,但能滿足臨床需求,且更有利于牙根的保護。
[Abstract]:Objective: to study the effect of different dentin shoulder collar and post core system on the fracture resistance of dentine crown after artificial aging. Methods: 64 mandibular first premolars extracted by orthodontic treatment within three months were randomly divided into 8 groups (n = 8). Different dentin shoulder collar and post core type. A1 group: 360 擄dentin shoulder collar glass fiber post resin core. A2 group: 360 擄dentin shoulder collar cast cobalt-chromium alloy post core. B1 group: 180 擄buccal side shoulder collar glass fiber post resin core .B2 Cast cobalt-chromium alloy post core. C1 group: 1% 180 擄tongue side dentin shoulder collar fiberglass resin post core. C2 group: 1 180 擄tongue side dentin shoulder collar casting cobalt-chromium alloy post core. D1: 180 擄cheek. The resin core of glass-fiber post. D2: 180 擄on the shoulder collar of lingual dentin, and the cobalt-chromium alloy post core cast on the shoulder collar of lingual side dentin. The height of dentin shoulder collar was 2 mm and the thickness was (1.2 鹵0.2) mm.. All the isolated teeth were repaired with cobalt-chromium alloy cast metal crown according to the standard of full-crown preparation. All 8 groups of samples were treated with cold and hot cycles (5 鈩，

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