DDS 8126 2- final NGU access to anteriors_76c8df7ad677f750301a2f252f2bff52.pdf

Access To Root Canal System :Anterior Teeth BDS 8126 Date : xx / xx / xxxx Aims: The educational aims of this lecture are to explain the pulp space morphology of anterior teeth to establish an understanding of the shape of access to root canals in those teeth. Objectives: On completion of this l...

Access To Root Canal System :Anterior Teeth BDS 8126 Date : xx / xx / xxxx Aims: The educational aims of this lecture are to explain the pulp space morphology of anterior teeth to establish an understanding of the shape of access to root canals in those teeth. Objectives: On completion of this lecture, the student should have an understanding of how to assess the root canal system in anterior teeth keeping in mind the pulp space morphology. Pulp Space Morphology Each tooth in the dental arch contains pulp tissue The pulp is a connective tissue that is encased within hard tooth structure It is located within the center of the tooth and is entirely enclosed within dentin except at the apical foramen The pulp space is divided: 1- Coronal pulp space: it is the space occupied by the pulp tissue within the crown A- pulp chamber: It is the pulp that lies within the crown of the tooth, the shape of the pulp chamber usually reflects the external form of the crown. B- Pulp horns: These are accentuations in the roof of the pulp chamber that lie directly below cusps and developmental lobes 2-Radicular Pulp: It is the space occupied by the pulp tissue within the root A-Root canal: It is the part of the pulp space that lies within the root of the tooth. It starts by an orifice and ends by the apical foramen. B- Accessory canal: These are lateral branches of the main root canal communicating the pulp space with the periodontium and ending with accessory foramina Apical foramen: It is an aperture near or at the apex of the root through which blood vessels and nerves of the pulp would enter or leave the pulp cavity Root Canal Classes • Root canals can be classified according to maturity ( completion of root formation) and curvatures into:  Class I Class II Class III Mature: CLASS I Straight CLASS II Slight Curved Severe Dilacerated Bayonet CLASS III Tubular Immature Blunder Buss Types Of Root Canal Configurations • Developed by Weine to describe the different possible configurations of the root canal systems within the single root Root canal system may take one of these forms: Wiene’s classification Type I : •Single orifice •Single canal •Single apical foramen Type II : Two orifices.  Two root canals.  One apical foramen.  Type III : Two orifices  Two root canals  Two apical foramina.  Type IV: One orifice.  Single root canal.  Two apical foramina.  Type V One orifice with single canal  Splits into two canals then join to exit  One apical foramen  Type VI Two orifices  Two canals join into on canal and then split into two canals with  Two apical foramina  Types Orifice Root canal Apical foramen Type I 1 1 1 Type II 2 2 1 Type VI Type III 2 2 2 Type IV 1 1 2 Type V 1 2 1 Type VI 2 1 2 Pulp Space Morphology of Anterior Teeth Pulp anatomy: 1-Number of roots. 2- Number of root canals. 3- Number of pulp horns. 4- Access cavity and outline form 5-Mesiodistal dimension and bucco-lingual dimension. 6- Cross section of the root. Maxillary Central Incisor 1-Number of roots: one root (100%) 2-Number of root canals: One root canal (Type I) 3-Number of pulp horns: Three pulp horns in newly erupted teeth. 4-Outline form: From palatal surface & triangular in shape 5- MD--BL dimension: Wider mesiodistally than buccolingually. 6- Root canal cross-section: •Cervical, nearly triangular with base labially and apex lingually. •Middle, is ovoid. •Apical, round in shape. Apical Middle Cervical Maxillary lateral Incisor Similar to morphology of maxillary central incisor with very little differences. 1-Number of roots: One root 100% 2-Number of root canals: One root canal (Type I) 3-Three pulp horns 4-Outline form: From palatal surface & triangular in shape The external access outline form for the maxillary lateral incisor may be a rounded triangle or an oval, depending on the prominence of the mesial and distal pulp horns 5-Mesiodistal view Same as the maxillary central incisor except for 3 differences: a- Wider buccolingually than mesiodistally b- Crown is smaller c- The root has a curvature in a distal and palatal direction 6-Root cross-section: •same as the maxillary central incisor. •Cervical triangular or oval in labiolingual direction ApicaL middle cervical Maxillary Canine 1-Number of roots: One root 100% 2-Number of root canals: One root canal Type I. 3- No of pulp horn: one pulp horn 4-Access cavity preparation & outline form: From palatal surface Oval in shape 5- MD-BL dimension: • The pulp chamber is very wide BL than MD 6-Root cross-section Apical Middle Cervical Mandibular Incisors 1-Number of roots: •One root usually 2-Number of root canals: •One canal 60-70% Type I •Two canals 30-40% • Type II • Type III 3- Three pulp horns 4-Access cavity preparation & outline form: •From lingual surface & triangular in shape •5-MD-BL •The pulp chamber is wide BLthan MD 6-Cross section Apical Middle Cervical Mandibular Canine 1-Number of roots : 1 root (rarely 2 roots can be found buccal and lingual) 2-Canal type: type I 94% type II or III 6 % 3-Access cavity & outline form: From lingual surface Oval in shape (incisocervical direction) 4- MD-BL dimension: • The pulp chamber is very wide BL than MD 6-Root canal cross-section •Cervical, cross section of the root is oval labiolingually. •Middle, cross-section is oval to ovoid. •Apical, the canal is round in cross-section Apical middle cervical Presented by: Shaimaa Gawdat Lecturer Of Endodontics, Cairo University Endodontic Cavity Preparation IntraCoronal cavity preparation IntraRadicular cavity preparation (Access Cavity ) (Cleaning and Shaping) Access is the key that opens the door to maximize cleaning, shaping and obturation Access Leads to Success Creation of an opening from the external surface of the tooth to the pulp chamber projecting out its side walls and internal anatomy to the outside Principals Of Access Cavity Preparation Outline form Removal of carious dentine Convenience form Toilet of the cavity Principle I: Outline Form: It should be correctly shaped to project the internal anatomy of the pulp to the outer surface & positioned to establish complete access for instrumentation from cavity margin to the apical foramen. Factors affecting Outline Form 1) Shape of the pulp chamber. e.g. * Incisor ---} Triangular in shape based incisally & apex cervically. * Canines ---} Oval Inciso-cervically 2) Size of the pulp chamber (age) 3) Number, Position & Curvature/ Direction of root canals (accommodate all canals to be prepared without interference). Principle II: Convenience Form: Modification of the cavity outline form to establish greater convenience (visibility and accessibility) in the preparation as well as obturation of the root canals Benefits of Convenience Form: 1) Unobstructed (Straight line) access to the canal orifice & searching for extra canal Without interference 2) Direct access to the apical foramen Without strain 3) Complete authority over the enlarging instruments. 4) Cavity expansion to accommodate filling techniques. Principles III: Removal of the Remaining Carious Dentin & Defective Restorations: Benefits: 1) To eliminate mechanically as many micro-organisms as possible from the interior of the tooth. 2) To eliminate the discolored tooth structure. 3) To eliminate the possibility of micro-organisms entrance with saliva leakage through defective restoration. 4) To avoid detached tooth or restoration particles from entering & occluding the RCs. 5) To assess the restorability of the tooth. Removal of Unsupported Tooth Structure: Unsupported tooth structure should be removed to prevent tooth fracture during or between procedures. Principle IV: Toilet of the cavity: (Irrigation of the Cavity) All the detached carious dentin, debris & necrotic material must be flushed away from the pulp chamber before Radicular preparation to avoid: 1) Obstruction of the canal during enlargement. 2) Increase bacterial population within the canal 3) Discoloration of the crown. Endodontic Coronal cavity preparation of maxillary and mandibular anteriors : 1- Point of entry: - On the lingual surface at the middle-middle third - If there is incisal attrition and you are unable to divide the lingual surface into thirds so  above the cingulum 2- Steps: i- Gaining access ii- Deroofing iii- Flaring 2- Steps: i- Gaining access - - Initial penetration is made with round bur. Bur is held perpendicular to long axis to create an indentation or until reaching the dentine to avoid slippage Then it is directed 45 degree to the long axis of the tooth till penetration of pulp chamber The operator will feel two drops during gaining access. Two Drops Drop into dentin Drop into the pulp chamber Can we start with the 45° angle? Are the 2 drops felt in all teeth or not? 2- Steps: ii- Deroofing Carried out using round bur or tapered stone with round end using motion from inside pulp chamber to outside (brushing motion) to remove the pulp horns. 2- Steps: iii- Flaring • • It is done using tapered stone with round end for smoothening and finishing for cavity dentinal walls and margins. Tapered diamond stone then penetrates to the pulp chamber parallel to tooth long axis. Errors In Access Cavity Preparation Discolouration Gouging Ledge Perforation Aims: The educational aims of this lecture are to explain the pulp space morphology of anterior teeth to establish an understanding of the shape of access to root canals in those teeth. Objectives: On completion of this lecture, the student should have an understanding of how to assess the root canal system in anterior teeth keeping in mind the pulp space morphology. Reading material: -The dental reference manual, Geraldine M. Weinstein, springer 2017 (Chapter 12) -Essential skills for dentists, Peter A.Mossey et al, Oxford, 2006 (Chapter 2.6) -Endodontics, Kishor Gulabivala and Yuan-Ling NG, Mosby Elsevier 2014 -Harty`s endodontics in clinical practice, Bun San Chong, Elsevier 2017 -Clinical endodontics, Lief Tronstad, Thieme 2009 (main reference) Thank you Date : xx / xx / xxxx