Longitudinal Tooth Fracture

Tooth fractures

狀況分為二種：by trauma (accident) or by masticatory force

MASTICATORY FORCE TOOTH FRACTURES

I.            Involve 後牙，通常是 vertical or oblique 方向裂開 (longitudinal tooth fractures)

II.          非立即性，需要時間develop

Craze line

簡述	裂痕僅 involve 到 enamel
特點	Facial (buccal) or lingual (palatal) 垂直裂痕黑線，後牙通常延伸跨過 marginal ridge
Etiologies	常見於成人恆牙齒列
Symptoms	無
Diagnosis
Treatments	不需要
備註	Prognosis : Good

Fractured cusp

簡述	牙冠的 cusp 斷裂，可能是完整或不完整的
特點	Mesio-distally 裂痕和 facio-lingually 裂痕向gingiva方向延伸聯合形成cusp斷裂
Etiologies	l   Restoration 範圍太大 l   Traumatic injury (立即性)
Symptoms	u  Biting pain or rebound pain u  Thermal sensitive u  Pulp or periapical symptoms
Diagnosis	l   Biting test (by tooth sloth, rubber or cotton) l   Cold test l   EPT test, percussion and palpation test l   X-ray or CT image
Treatments	將 fractured cusp 碎片移除， 1.          If not involving pulp, OD restoration or crown protection 2.          If involving pulp, RCT or Through crown RCT 3.          If involving pulp but RCT not recommended, extraction
備註	做RCT就是想保留牙齒，如果做RCT過程沒辦法moisture control或是做完之後沒辦法做 prosthodontics，會考慮拔掉

Cracked tooth

簡述	牙齒咬合面出現 MD 方向裂痕，可能偏向 buccal or lingual，向gingiva方向延伸
特點	After wedging force, tooth can not be separated.
Etiologies	Mand. Second molar > mand. First molar > max. second molar or premolar
	l   Aging l   Restoration 範圍太大 l   Dental history of other cracked tooth (咬力太大，國字臉)
Symptoms	u   Biting pain or rebound pain u   Thermal sensitive u   Pulp or periapical symptoms
Diagnosis	l   Biting test (by tooth sloth, rubber or cotton) l   Cold test l   Staining l   Transillumination test l   顯微鏡觀察 l   Wedging test l   EPT test, percussion and palpation test l   X-ray or CT image
	如果牙齒上有restoration要先移除才能看有沒有cracked line
Treatments	1.          If not involving pulp, OD restoration or crown protection 2.          If involving pulp, RCT or Through crown RCT
備註	Prognosis : questionable or bad

Split tooth

簡述	同 cracked tooth，但進展成完全斷開
特點	After wedging force, tooth can be separated.
Etiologies	同 cracked tooth
Symptoms	同 cracked tooth
Diagnosis	同 cracked tooth
Treatments	考慮 whether restorable 1.          If restorable, RCT or Through crown RCT 2.          If non-restorable, extraction
備註	做RCT之前要考慮未來這顆牙齒有沒有復形的可能，如果沒有要考慮拔除

Vertical root fracture

簡述	從牙根往 cervical 方向的裂痕，只 involve root portion
特點	Facial-lingually 裂痕 (和 cracked tooth MD裂痕不同)
Etiologies	Lower molar > upper premolar > lower premolar
	l   RCTed tooth l   Intraradicular post placement l   Chewing habit (eg, 東方人喜歡吃花生、肯骨頭等) l   Aging (>60歲)
Symptoms	u   Asymptomatic or mild discomfort u   Biting pain or rebound pain u   Thermal sensitive
Diagnosis	l   Deep and narrow probing depths (若有對稱性：80~90%確定是) l   Periodontal-type abscess l   Biting test (by tooth sloth, rubber or cotton) l   Cold test l   EPT test, percussion and palpation test l   X-ray (J-shaped RL pattern)or CT image l   Surgical assessment (打開來看阿！) : a.          lower molar 常在 mesial root 直接往下切 b.          premolar 在apex開一個bone cavity
Treatments	1.          Extraction 2.          Amputation (把有問題的root去掉，上方crown留著) 3.          Hemisection (把有問題的root+上方crown去掉)
備註

Prevention of longitudinal tooth fracture

1.          Patient education (不要吃太硬的東西)

2.          Occlusal reduction