mandibular 2 premolar

60
MANDIBULAR 2 PRE MOLAR BY O.R.GANESH MURTHI M.Sc.D ENDO

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anatomy and access preparation ... anomalies of premolar

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Page 1: mandibular 2 premolar

MANDIBULAR 2 PRE MOLAR

BYO.R.GANESH MURTHI

M.Sc.D ENDO

Page 2: mandibular 2 premolar

INTRODUCTION

EXTERNAL ANATOMY

INTERNAL ANATOMY

VARIATIONS

ANOMALIES

ENDODONTIC

CORRELATION

OUT LINE

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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.

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Average time of eruption : 11 to 12 years

Average age of calcification : 13 to 14 years

Average length : 22.3 mm

Mandibular 2nd premolar

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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

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YOUNG

Reversible Pulpit'sIrreversible Pulpit's Necrotic Pulp

Apexogenesis

Pulp Capping or Pulpotomy

Closed Apex Open Apex

RCT Apexification Obturation

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Average Length : 21.4 mm

Maximum Length : 23.7 mm Minimum Length : 19.1 mm

Range : 4.6 mm

Mandibular 2nd premolar

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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.

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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

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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

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Lingual aspect

mesiodistal diameter = that from Buccal aspect Occlusal surface cannot be seen fully

Occlusal plane is perpendicular to tooth Axis

Mandibular 2nd premolar

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2 lingual cusps (most commonly) • Mesiolingual – major, 2/3 MD diameter, same height as Buccal

• Distolingual – minor

Lingual groove

Mandibular 2nd premolar

2/3

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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

Page 14: mandibular 2 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

Page 15: mandibular 2 premolar

Mandibular 2nd premolar

Occlusal view

Mesial & Distal triangular fossaeeach contains• A pit• Mesiobuccal & Distobuccal grooves

MD

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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

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Mandibular 2nd premolar

Pulp Buccolingual section• Pulp chamber iswider• Pulp horns are ofequal height

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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

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Mandibular 2nd premolar

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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

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Mandibular 2nd premolar

ROOTS AND ROOT CANALS

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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 %

Page 23: mandibular 2 premolar

ROOTS AND ROOT CANALS

One root canal dividing in to two at apex

Single canal that has divided and cross over at the apex

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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

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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

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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

Page 27: mandibular 2 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

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Anatomic relationships in situ

The mental canal and foramen are close to the root apex Radiograph appearance may shows peiapical pathosis

Mandibular 2nd premolar

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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

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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.

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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

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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

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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

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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

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THE ACCESS CAVITY

Buccolingual ovoid outline form reflects the anatomy of the pulp chamber and position of the centrally located canal.

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• The lingual portion should be prepared well for a straight line access and location of lingual canal.

THE ACCESS CAVITY

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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

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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.

Page 39: mandibular 2 premolar

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

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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

Page 41: mandibular 2 premolar

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

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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

Page 43: mandibular 2 premolar

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

Page 44: mandibular 2 premolar

Anomalies

Dens invaginatus

Dens evaginatus

Gemination Dilaceration

Mandibular 2nd premolar

Page 45: mandibular 2 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

Page 46: mandibular 2 premolar

• 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

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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.

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DENS EVAGINATUS

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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.

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Mandibular second premolar with three root canalsReport of a case

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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

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Pre-operative radiograph showing the poor root canal filling.

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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

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Working length radiograph showing files in the three root canals.

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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

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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.

Page 57: mandibular 2 premolar

Obturation of the three root canals

Page 58: mandibular 2 premolar

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

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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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THANK YOU ALL