Objective: To compare the conventional lingual access to labial access preparation in mandibular anterior teeth in terms of achieving a straight-line access to the apex with maximum conservation of coronal tooth structure. Method and Materials: One hundred extracted human mandibular incisors with intact crowns and patent root canal configuration were collected, numbered, and weighed in a microbalance. Each tooth was radiographed in a labiolingual direction, traced, evaluated, and assigned into 1 of 5 classes as per the classification given by Zillich and Jerome (1981).The frequency of types of canal configuration in each class was determined as a percentage. The teeth were randomly divided into 2 groups of 50 teeth. Access was prepared lingually in group 1 and labially in group 2 to achieve a straight-line access to the apex. The amount of tooth tissue lost as a result of access preparation was measured for all teeth. Results: A total of 71 teeth had their tracing projections buccal and buccoincisal. The tooth tissue lost during lingual access was significantly more than that lost during labial access preparation (P .001). Conclusion: A labial access opening for endodontic treatment of mandibular incisors would facilitate straight-line access to canals more consistently and conservatively. Schlagwörter: labial access, lingual access, mandibular incisors, straight-line access, tooth-tissue loss