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MANDIBULAR 2 PRE MOLAR
BYO.R.GANESH MURTHI
M.Sc.D ENDO
INTRODUCTION
EXTERNAL ANATOMY
INTERNAL ANATOMY
VARIATIONS
ANOMALIES
ENDODONTIC
CORRELATION
OUT LINE
INTRODUCTION The term premolar is used to designate any tooth in the permanent dentition that replaces a primary molar. fifth tooth from midline in the mandible quadrant. They assist canine in shearing and support corners of the mouth from sagging.
Average time of eruption : 11 to 12 years
Average age of calcification : 13 to 14 years
Average length : 22.3 mm
Mandibular 2nd premolar
Significance of average time of eruption,age of calcification,tooth length & root curvature:
IT HELPS IN DIAGNOSIS AND TREATMENT PLAN
TREATMENT IS DIFFERENT IN ADULT AND YOUNG
ADULT NECROTIC PULP
IRREVERSIBLE PULPITIS
RCT
YOUNG
Reversible Pulpit'sIrreversible Pulpit's Necrotic Pulp
Apexogenesis
Pulp Capping or Pulpotomy
Closed Apex Open Apex
RCT Apexification Obturation
Average Length : 21.4 mm
Maximum Length : 23.7 mm Minimum Length : 19.1 mm
Range : 4.6 mm
Mandibular 2nd premolar
Mandibular 2nd premolar
IMPORTANCE It helps in the determining the working length and better assumption of the radiograph
Consideration must be given to the mental foramen which lies in close proximity to the apex. Avoid over instrumentation and overfill.
Buccal aspect
Long pointed buccal cusp in the occlusal profile
Mesial cusp ridge is shorter than distal
Cusp tip is a little mesial to the tooth midline
Mandibular 2nd premolar
Buccal aspect
Mesial & Distal outlines are markedly converging
Cervical line is flat mesiodistal compared to that of canine
Root is conical with pointed apex
Mandibular 2nd premolar
Lingual aspect
mesiodistal diameter = that from Buccal aspect Occlusal surface cannot be seen fully
Occlusal plane is perpendicular to tooth Axis
Mandibular 2nd premolar
2 lingual cusps (most commonly) • Mesiolingual – major, 2/3 MD diameter, same height as Buccal
• Distolingual – minor
Lingual groove
Mandibular 2nd premolar
2/3
Mesial aspectTriangular ridges of Buccal and Mesio lingual cusps don’t not form a continuous crest
Distal aspectBoth lingual cusps are seen
Mandibular 2nd premolar
Occlusal aspectSquare profile Mesial & Lingual profiles are parallelMore than half of Buccal surface is visibleBuccal ridge is less prominent than that of mandibular 1st premolarMesial & Distal Marginal ridges are equal in length
Mandibular 2nd premolar
Mandibular 2nd premolar
Occlusal view
Mesial & Distal triangular fossaeeach contains• A pit• Mesiobuccal & Distobuccal grooves
MD
Mandibular 2nd premolarOcclusal viewGrooves (Y shape meet at the central pit)• Mesial groove separates Buccal & Mesiolingual triangular ridges – runs obliquely• Lingual groove separates lingual cusps• Distal groove separates Buccal & Distolingual triangular ridges
MLDL
B
Mandibular 2nd premolar
Pulp Buccolingual section• Pulp chamber iswider• Pulp horns are ofequal height
Mandibular 2nd premolar
PULP CHAMBER
Mesiodistal width - narrow Buccolingual width - wide Lingual horn is more prominent under a well developed lingual cusp 30 lingual tilt Cross section – ovoid with greater diameter in buccolingually
Mandibular 2nd premolar
Mandibular 2nd premolarROOTS AND ROOT CANALS
The Mandibular second premolar resembles the first premolar, but the lingual canal is present only occasionally. The root canal is oval in cross-section and rather straight with only a slight distal curvature in some canals
Mandibular 2nd premolar
ROOTS AND ROOT CANALS
Mandibular 2nd premolar
1 Canal 1 foramen - 85.5 %1 canal 2 foramen - 11.5 %2 Canal 1 foramen - 1.5 %3 canal - 0.5 %
ROOTS AND ROOT CANALS
Distal curve – 40 %Straight – 39 %Buccal curve – 11 %Lingual curve – 10 %
ROOTS AND ROOT CANALS
One root canal dividing in to two at apex
Single canal that has divided and cross over at the apex
1 CANAL SEPARATE IN TO 2 CANALS
DIVISION IS BUCCAL AND LINGUAL
LINGUAL CANAL SPLITSFROM THE MAIN CANALAT SHARP ANGLE IT IS VISUAL CONFIGURATION
AS LOWER CASE LETTER h
BUCCAL CANAL IS STRAIGHT
PORTION OF THE h
ROOT CANAL ORIFICES
ACCESSORY CANALSMostly found in the apical third Lateral canals may be found in 44.3% cases Usually a good biomechanics preparation cleanses the canal well and is filled with the sealer during Obturation.The ability to cleanse and seal these canals have an impact on the prognosis
Note :
• When only one canal is present , it is usually found in the center of the access preparation.
• If only one canal is found, but it is not in the centre of the tooth, it is probable that another canal is present
Mandibular 2nd premolar
1 CANAL PRESENT
LOCATED IN THE CENTER OF THE ACCESS PERPARATION
NOT LOCATED IN CENTEROF THE ROOT
ANOTHER ORIFICES PROBELY EXISTS
CLINICIAN SHOULD SEARECH FOR OPPOSITE SITE
ROOT CANAL ORIFICES
Anatomic relationships in situ
The mental canal and foramen are close to the root apex Radiograph appearance may shows peiapical pathosis
Mandibular 2nd premolar
Avoid over instrumentation and overfill When viewing an x-ray of this area, the mental foramen is sometimes misdiagnosed as a premolar abscess. Therefore, before performing root canal therapy, make sure all diagnostic tests confirm your finding.
Anatomic relationships in situ
FAST BREAK When numerous canal
are present, the preoperative radiograph often indicates a "fast break." This appears as a relatively patent canal space in the coronal portion of the tooth that suddenly disappears.
Note:
If a straight-on preoperative radiograph of a Mandibular 2 premolar shows the pulp canal disappearing in mid-root, this is an important indication that two canals are present.
FAST BREAK
The mandibular second premolar is similar to the first premolar, with the following differences:
The lingual pulp horn usually is larger
The root and root canal are more often oval than round
The pulp chamber is wider buccolingually
Mandibular 2nd premolar
The access cavity form for the Mandibular second premolar varies in at least two ways in its external anatomy. 1.The crown typically has a smaller lingual inclination less extension up the buccal cusp incline is required to achieve straight-line access.
2. The lingual half of the tooth is more fully developed; therefore the lingual access extension is typically halfway up the lingual cusp incline.
THE ACCESS CAVITY
The Mandibular second premolar can have two lingual cusps, sometimes of equal size. When this occurs, the access preparation is centered mesiodistally on a line connecting the buccal cusp and the lingual groove between the lingual cusp tips.
THE ACCESS CAVITY
THE ACCESS CAVITY
Buccolingual ovoid outline form reflects the anatomy of the pulp chamber and position of the centrally located canal.
• The lingual portion should be prepared well for a straight line access and location of lingual canal.
THE ACCESS CAVITY
the pulp is large in a youngtooth, very wide in the Buccolingual dimension.Debridement of the chamber is completed during coronal cavity preparation with a round bur
CROSS SECTIONAL IN CERVICAL LEVEL
CROSS SECTIONAL IN MIDROOT LEVEL AND APICALMidroot level: the canal
continues to be long ovoid and requires perimeter filing Apical third level: the canals, generally round, are shaped into round, tapered preparations.Preparation terminates at the cementodentinaljunction, 0.5 to 1.0 mm from the radiographicapex.
MANDIBULAR 2 PREMOLAR TEETHERRORS IN CAVITY PREPARATION
PERFORATION
at the disto gingival caused by failure to recognize that the premolar has tilted to the distal
INCOMPLETE
preparation and possible instrument breakage caused by total loss of instrument control. Use only occlusal access, never buccal orproximal access.
MANDIBULAR 2 PREMOLAR TEETH ERRORS IN CAVITY PREPARATION
MANDIBULAR 2 PREMOLAR TEETHERRORS IN CAVITY PREPARATION
BIFURCATION
Of a canal completely missed,caused by failure to adequately explore the canal with a curved instrument
MANDIBULAR 2 PREMOLAR TEETHERRORS IN CAVITY PREPARATION
APICAL PERFORATION
Of an invitingly straightconical canal. Failure to establish the exact length of the tooth leads to trephination of the foramen
MANDIBULAR 2 PREMOLAR TEETHERRORS IN CAVITY PREPARATION
PERFORATION
at the apical curvature caused by failure to recognize, by exploration, buccal curvature.A standard bucco lingual radiograph will notshow buccal or lingual curvature
Anomalies
Dens invaginatus
Dens evaginatus
Gemination Dilaceration
Mandibular 2nd premolar
DENS INVAGINATUS Dens invaginatus is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. Affected teeth show a deep infolding of enamel and dentine. Occurs before calcification of the teeth. Also known as dens in dente
• The treatment modalities depend on the degree of complexity of its anatomy.
• They include nonsurgical endodontic treatment, endodontic surgery and extraction.
• In cases in which there is an immature apex, calcium hydroxide is used to stimulate apexification
TREATMENT OF DENS INVAGINATUS
DENS EVAGINATUS• Dens evaginatus is a
developmental anomaly that manifests as a tubercle emerging from the surface of the affected tooth.
• It occurs most frequently in the premolars.
• Higher prevalence among people of Mongoloid origin.
DENS EVAGINATUS
Clinical importance• Fracture or wear of the tubercle could
lead to pulp necrosis before root formation is complete.
• Various prophylactic treatments like selective grinding, application of resin, restorations and partial Pulpotomy can be done.
• If there is complete pulpal necrosis in an immature tooth, MTA can be used in the apex followed by endodontic treatment.
Mandibular second premolar with three root canalsReport of a case
A 20- year-old male with non contributory medical history was referred to the clinics of the SaudiBoard in Advanced Restorative at the Faculty of Dentistry, for evaluation of root canal therapy of a mandibular 2 premolar.
Clinical examination revealedthat the tooth responded positively to percussion but not to palpation.
Radiographic examination revealed short and inadequate root canal filling
Pre-operative radiograph showing the poor root canal filling.
The tooth was isolated with rubberdam, the old amalgam filling was removed and the access cavity preparation was established.
Three canals were located,buccally, lingually and an extra canal in the middle. The working length was checked radiographically
Working length radiograph showing files in the three root canals.
The canals were conventionally instrumented to a # 35K file using crown-down pressureless technique, irrigated with 5.25 percent sodium hypochlorite, dried with sterile paper points and sealed with calcium hydroxide paste The access opening was closed with Cavit. The patient returned asymptomatic after 1 week, the tooth was isolated with rubber dam; the canals were instrumented with file #35 and irrigated with sodium hypochlorite to remove all the remnants of the calcium hydroxide, and then dried with paperpoints
Master cone was selected and the canals were filled with gutta-percha and AH26 sealer cement using lateral condensation.
Access opening was sealed with amalgam restoration. Post-operative radiograph was taken to confirmthe quality of the filling .The patient was referred to the prosthetic clinic for crown construction.
Obturation of the three root canals
Location and thorough instrumentation of all the canals in the root of a diseased tooth normally ensure success of the endodontic therapy. Presented is a case of mandibular second premolar which was referred for endodontic therapy. Clinical and radiographic examination revealed inadequate root canal filling. Three canals were located. Endodontic therapy was performed under asepticconditions
DISCUSSION
References Endodontics 5th Edition - Ingle & Bakland Pathways Of The Pulp 6th Edition - Cohen Endodontic Practice 11th Edition Grossman A Textbook Of Oral Pathology - Shafer Wheeler’s Dental Anatomy, Physiology and Occlusion 7th Edition – Ash Colors Atlas of Endodontics - William T. Johnson Medical principles and practice
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