垂直牙根斷裂臨床特徵分析

Analysis of Clinical Characteristics of Vertical Root Fracture

垂直牙根斷裂（vertical root fracture）是臨床上常見卻難以正確診斷的棘手問題。本研究目的為分析國人已接受根管治療與未接受根管治療，而發生垂直牙根斷裂牙齒之臨床特徵，並進一步歸納出臨床上可作為診斷之依據。以回溯性研究方法，收集約一百例垂直牙根斷裂之病例，將其分成已接受根管治療及未接受根管治療兩大組，記錄患者基本資料、主訴、臨床症狀、放射線影像、斷裂牙根以及牙齒形態；並利用立體顯微鏡觀察裂紋走向、位置、與咬耗平面之夾角等，進行統計及分析。結果發現，兩組的垂直牙根斷裂均好發於牙冠嚴重磨耗（77.4-88.2%）且扁平的牙根（61.8-75.8%）上，以大臼齒的近心牙根發生率最高（64-85.7%），多為頰舌側走向（91.2-91.9%），且於未根管治療組別亦發現三例側根斷裂，走向為較寬的近遠心方向，顯示牙根斷裂會沿著牙根較寬的方向發生；同時，未經根管治療而產生垂直牙根斷裂的牙齒具有根叉（furcation）位置較低的現象（61.8%），牙根於比例上有較短小的特徵。此外，裂紋走向與咬耗平面幾乎成垂直之夾角（82.4-93.5%）。牙冠的嚴重咬耗、扁平牙根、牙根比例較短小的形態與垂直牙根斷裂的發生有強烈的相關性。放射線影像發現有牙周韌帶變寬（79-85.3%）、根管變寬（19.4-29.4%）、角形骨缺損（44.1-45.2%）等現象；同時臨床特徵上有極高比例（85.3-85.5%）有窄且深的牙周探測深度。

Vertical root fracture is a common but thorny problem. The purpose of this study was to analyze the clinical characteristics of vertical root fractured teeth, which may or may not have been endodontically treated, and to conclude the hints for clinical diagnosis. We collected about one hundred cases of vertical root fracture and divided them into two groups, endodontically treated and non-endododntically treated cases. We then recorded the patient profiles, their chief complaint, clinical signs and symptoms, radiographic images, and teeth morphology. Using stereomicroscope, we observed the fracture line direction and location as well as the angle between the fracture line and the attrite plane. The data was compiled into statistics and analyzed. The results revealed that most of the vertical root fractures occurred in teeth with severe attrite crown and flat root. Numerous bucco-lingual oriented fractures occurred in the mesial root of molars, and we found three non-endodontically treated cases with mesio-distal oriented fractures in the palatal roots. We concluded that fracture lines formed at opposite ends of the latitudinal long axis of the root and propagated along the longitudinal direction of the root. Furthermore, the characteristics of low furcation and proportionally short root in molars were found, and the angle between the fracture line and attrite plane was nearly a right angle. Severe attrite crowns, flat roots, and proportionally thinned-small root may be predisposing factors of vertical root fracture. Moreover, by generalizing the patients' age, gender, tooth morphology, clinical sign and symptom, and radiographic images, we concluded hits for diagnosing vertical root fracture.