Questions and Answers
What does the pulp space reflect?
external form of the tooth
What factors affect canal morphology?
age, race, irritants (caries, abrasion/erosion, trauma), calcification (pulp stones, diffuse), resorption (internal/external)
What is internal resorption of a canal?
A defect of the internal aspect of the root following necrosis of odontoblasts due to chronic inflammation and bacterial invasion of the pulp tissue.
What is external resorption of a canal?
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How does fusion alter tooth shape?
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How does gemination alter tooth shape?
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What is concrescence and where does it usually occur?
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What is dilaceration?
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What three factors of canal morphology is Weine's classification based on?
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Describe Weine classification type I.
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Describe Weine classification type II.
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Describe Weine classification type III.
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Describe Weine classification type IV.
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What are the four major objectives of access opening?
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What is the purpose of attaining straight line access?
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When should an endodontic file be deflected during straight line access?
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What is ledging?
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What is transporting?
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What is zipping?
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What is the average length of a maxillary central incisor?
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How is a maxillary central incisor classified based on Weine's classification?
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What is the root curvature for maxillary central incisors and their % possibilities?
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What is the shape of the root canal in the coronal 1/3 of a maxillary central incisor and what is its widest dimension?
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What is the shape of the root canal in the apical 1/3 of a maxillary central incisor?
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Describe maxillary central incisor access including shape, placement, size, and internal form.
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What is the average length of a maxillary lateral incisor?
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How is a maxillary lateral incisor classified based on Weine's classification?
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What is the root curvature for maxillary lateral incisors and their % possibilities?
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What is the shape of the root canal in the coronal 1/3 of a maxillary lateral incisor and what is its widest dimension?
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Describe maxillary lateral incisor access including shape, placement, size, and internal form.
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What is the average length of a maxillary canine?
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What is the longest tooth in the mouth and how long is it on average?
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How is a maxillary canine classified based on Weine's classification?
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What is the root curvature for maxillary canines and their % possibilities?
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What is the shape of the root canal in the coronal 1/3 of a maxillary canine and what is its widest dimension?
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What is the shape of the root canal in the apical 1/3 of a maxillary canine?
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Describe maxillary canine access including shape, placement, size, and internal form.
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What is the average length of a mandibular central incisor?
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How is a mandibular central incisor classified based on Weine's classification and its % possibilities?
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What is the root curvature for mandibular centrals and their % possibilities?
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What is the average length of a mandibular lateral incisor?
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How is a mandibular lateral incisor classified based on Weine's classification and its % possibilities?
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What is the root curvature for mandibular laterals and their % possibilities?
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What is the average length of a mandibular canine?
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How is a mandibular canine classified based on Weine's classification and its % possibilities?
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What is the root curvature for mandibular canines and their % possibilities?
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What is the outline form for maxillary incisors?
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What is the outline form for canines?
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What is the outline form for mandibular incisors?
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Initial external outline form should be how big compared to the final outline form?
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What are the key steps of access of anterior teeth?
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How should the bur be positioned during initial penetration of enamel for access to anterior teeth, and what bur should you use?
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How should the position of the bur change from initial penetration to penetration of the pulp chamber when accessing anterior teeth?
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What should you use to identify the canal orifice in anterior access?
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What bur should you use to achieve a smooth internal surface during anterior access?
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What instruments can you use to remove the lingual shelf?
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Study Notes
Anatomy and Morphology of Teeth
- Pulp space shape reflects the external form of the tooth.
- Factors affecting canal morphology include age, race, irritants (caries, abrasion, erosion, trauma), calcification (pulp stones), and resorption (internal and external).
Resorption Types
- Internal resorption: Involves a defect on the internal aspect of the root due to chronic inflammation and bacterial invasion; characterized by symmetric lesions and smooth margins on radiographs.
- External resorption: Starts in the periodontium and affects external tooth surfaces; may invade pulpal space; identified by irregular margins on radiographs and followable canal continuity.
Tooth Fusion and Shape Alterations
- Fusion: Two developing tooth buds combine, forming one large tooth; roots or canals may be separate or joined.
- Gemination: An incomplete split of a single tooth germ results in two joined crowns with a single root/canal.
- Concrescence: Fusion of two fully formed teeth only by cementum, typically between maxillary 2nd and 3rd molars.
- Dilaceration: Extraordinary curving or angulation of the root.
Weine's Classification of Canal Morphology
- Based on number of canal orifices, root canals, and apical foramina for single-rooted teeth.
- Type I: One orifice, one canal, one apical foramen.
- Type II: Two orifices, two canals, one apical foramen.
- Type III: Two orifices, two canals, two apical foramina.
- Type IV: One orifice, two canals, two apical foramina.
Access Opening Objectives
- Unroof the pulp chamber to locate canal orifices.
- Achieve straight-line access for better instrument control.
- Conserve tooth structure during the procedure.
- Ensure correct outline form regarding size, shape, position, and internal form.
Access Techniques
- Straight-line access allows better control, reduced procedural errors (ledging, transporting, zipping), and improved obturation.
- Endodontic files should be deflected upon reaching the first curve in the canal's middle or apical third.
Common Endodontic Issues
- Leding: Instrument deviates from the canal path.
- Transporting: Continuing straight from a ledged path.
- Zipping: Creating an artificial apical foramen.
Average Lengths and Classifications of Anterior Teeth
- Maxillary central incisor: Average length 23 mm, classified as Type I (straight - 75%).
- Maxillary lateral incisor: Average length 23 mm, also Type I.
- Maxillary canine: Average length 26.5 mm, longest tooth, Type I classification.
- Mandibular central incisor: Average length 21 mm, Type I predominates.
- Mandibular lateral incisor: Average length 21 mm, also Type I.
- Mandibular canine: Average length 26 mm, Type I mostly.
Root Canal Shapes
- Maxillary incisors have an oval root canal in the coronal third (widest mesiodistally) and round in the apical third.
- Maxillary lateral incisors: Oval shape in the coronal third (widest buccolingually).
- Maxillary canines: Oval in the coronal third (widest faciolingually) and round in the apical third.
Access Forms for Anterior Teeth
- Maxillary Central Incisor Access: Triangle shape, middle 1/3 placement, >2 mm from incisal edge, smooth internal form.
- Maxillary Lateral Incisor Access: Rounded triangle or oval shape, similar placement and internal form to central incisors.
- Maxillary Canine Access: Oval shape and placement with similar internal forms to incisors.
Access Steps for Anterior Teeth
- Establish initial outline form of 1/2 to 3/4 of final.
- Penetration of pulp chamber roof and removal to identify canal orifice.
- Smooth internal surfaces with Endo Z bur.
Instrumentation and Bur Usage
- Use #2 or #4 round bur perpendicular to the lingual surface during initial penetration of enamel.
- Change from perpendicular to parallel during pulp chamber penetration using #2 or #4 FG or latch type bur.
- DG 16 utilized for identifying canal orifices.
- Gates-Glidden drills or proper gold SX rotary files recommended for removing lingual shelf.
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Test your knowledge on the anatomy and morphology of ant teeth with these flashcards. Each card focuses on key terms and definitions related to dental pulp space and canal morphology. Perfect for dental students and professionals looking to enhance their understanding.