Endodontics Problem-Solving in Clinical Practice

Constantin Grijincu

Endodontics Problem-Solving in Clinical Practice

Constantin Grijincu

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Abstract

Although every effort has been made to ensure that all owners of copyright material have been acknowledged in this publication, we would be glad to acknowledge in subsequent reprints or editions any omissions brought to our attention.

Figures (432)

Figure 1.2 A patient with facial swelling (arrowed).

Figure 1.1 Palpation of the submandibular lymph nodes. The clini- cian is positioned behind the patient and palpates the nodes gently with finger tips.

Figure 1.6 Sufficient opening is required to gain access to the teeth for endodontic treatment. Two fingers' width in the incisor region is perfectly adequate.

An external sinus tract on the chin that drained from the mandibular incisors.

A neglected mouth. The patient will need advice on oral hygiene prior to endodontic treatment.

A paralleling radiograph of the mandibular incisors showed a periapical radiolucency. The central incisors were non-vital, and pus was draining through the exter- nal sinus tract.

Testing tooth mobility by gently applying lateral forces between finger and thumb.

Figure 1.8 The overhanging restoration on the buccal surface of this mandibular molar has provided a site for plaque accumu- lation, and active caries is now present under the restora- tion.

Figure 1.9 A radiograph showing advanced recurrent/root caries (arrowed). This tooth is probably unrestorable.

Figure 1.11 Gently percussing a tooth with a mirror handle may elicit the classical ringing sound that occurs with replacement resorption (ankylosis).

Intraoral sinus tracts: These are usually seen on the attached buccal gingiva. The gingiva should be gently dried with a three-in-one syringe, and examined closely under good illumination (Figs. 1.14, 1.15). Running a fin- ger along the mucosa may elicit a discharge from the sinus tract (Fig. 1.16). The tract exit may not always be adjacent to the offending tooth (Fig. 1.17). Sinus tracts exit less com- monly on the palate (Fig. 1.18). When taking a radiograph for diagnosis it is useful to place a gutta percha point in the tract to identify the source of the problem (Figs. 1.19, 1.20). Palpating the buccal sulcus over the apices of the teeth, with a finger tip. Any tenderness or swelling is noted. Tenderness may be an indication of acute apical peri- odontitis.

Figure 1.14 An intraoral sinus tract in the anterior region. Mobility of fixed prosthodontics: Inserting a probe under the pontic of a bridge and apply- ing a pulling force can be used to test whether either abutment is loose (Fig. 1.26). The mar- gins of full crown restorations can be tested with a probe (Figs. 1.27, 1.28).

Figure 1.17 Figure 1.15 In this patient a sinus tract opposite the lower molar (indicated by ring) tracked along the mandible to the periapical abscess on the premolar. Sinus tracts do not always point adjacent to the offending tooth. Vitality test- ing and good radiological techniques are needed to iden- tify the source of the problem. An intraoral sinus tract in the posterior region.

A palatal sinus tract in the anterior region.

Pus discharging from the anterior sinus tract.

Figure 1.21 An extracted tooth with a vertical root fracture. In this case the tooth had fractured despite having been crowned.

Figure 1.22 An occlusal view of a maxillary premolar that had frac- tured vertically in a mesial-occlusal-distal plane.

Placing a gutta percha point in a sinus tract to identify the source of the problem. This will not be painful, as the sinus tract is often epithelialized. Topical anaesthetic gel may occasionally be required.

Figure 1.20 A radiograph of a gutta percha point inserted into a sinus tract adjacent to a mandibular molar.

Figure 1.24 There were 1.0-1.5 mm probing depths buccally.

Figure 1.26 Inserting a probe under the pontic of a bridge to test for mobility.

The probing depth of 7mm on the distal aspect of the tooth directly opposite to that on the mesial aspect was indicative of a vertical root fracture. Figure 1.23 The maximum periodontal probing depth on the mesial aspect was 7mm. The pocket shape was deep and nar- row.

Testing for marginal deficiencies around a crown using a Briault probe.

Figure 1.28 A DG16 probe (Hu Friedy, Chicago, IL, USA) can be used to test the margins of restorations.

Figure 1.31 Vaseline is placed on the tooth surface to prevent the rubber sticking.

The heated gutta percha is placed on to the tooth.

Figure 1.30 blot gutta percha can be used to test a tooth for heat sen- Sitivitv. The tooth is isolated with rubber dam and immersed in cold water.

: igure 1.35 The tip of the electric pulp tester is coated in toothpaste to improve conductivity.

Figure 1.36 A circuit is made when the patient holds the metal handle.

Figure 1.34 Adjacent teeth are sometimes isolated with rubber dam to prevent short-circuiting through metal restorations.

A fibre optic light for assessment of cracks.

A tooth is illuminated to visualize a crack (arrowed) Cutting a Test Cavity

Figure 1.41 A Tooth Slooth being used to apply pressure to an indi- vidual cusp. The X-ray machine should comply with cur- rent ionizing radiation regulations. A tube voltage of 70 kV is ideally suited for intraoral radiography. The beam produced by the X-ray head is divergent, and must be filtered and collimated to produce a parallel source. Filtration is equivalent to 1.5 mm of alu- minium for units up to 70 kV. Collimation

Figure 1.43 Biting on a rubber dam sheet may cause a cracked cusp to flex, aiding diagnosis.

Figure 1.47 The sensor is placed in a polythene cover to prevent cont amination and cross-infection. It can be held in position with the patient's finger, or in a special Rinn holder. A digital image of a root-treated tooth taken with the Schick sys- tem (Schick Technologies Inc, Long Island City, NY, USA); the image manipulation effects can be seen at the top of the screen.

Figure 1.51 The posterior Rinn holder, beam aiming device. The Rinn holder paralleling device for the posterior region.

The anterior Rinn holder, beam aiming device. The Rinn holder paralleling device (Dentsply, Weybridge, Surrey, UK) for the anterior region.

Figure 1.52 A lateral radiolucency may be an indication of a lateral canal. The anterior Rinn in use. The X-ray head is covered in a disposable polythene cover to prevent cross-infection.

Figure 1.55 A lateral canal has been filled during obturation; it lies adjacent to a lateral radiolucency.

Figure 1.56 Rotating the cone produced a radiograph, showing an unfilled second canal.

The completed obturation revealed an even more compli- cated root canal system. A bisecting angle film showed the horizontal root frac- ture (arrowed).

Figure 1.61 A cotton wool roll has been placed on the edentulous ridge to prevent the holder rotating.

With an edentulous ridge the Rinn holder needs to be supported, as in this case, where a periapical radiograph is required of the mandibular premolar.

Figure 1.63 The completed root canal treatment shows that the roots of the maxillary molars are superimposed on the radio- graph. A thorough and logical approach to diagnosis pre- vented incorrect treatment.

Figure 1.64 A radiograph of a tooth with pulpal necrosis; it was non- responsive to vitality testing.

The apical constriction The mesial root of a mandibular first molar in buccal- lingual section, showing various types of complex anatomy.

Figure 2.3 A microcomputed tomographic (MCT) scan of the pulp chamber of a mandibular second molar. Four pulp horns can be clearly seen. The orifices to the canals are funnel- like and extend into the canals, which are narrow mesiodistally.

Figure 2.4 A MCT scan of a mandibular first molar; the three pictures show the tooth rotated through 60 degrees. An access cavity has been cut and the root canals prepared. The root canal system is complex, and a fin can be seen between the two mesial canals. folds, producing interconnections that persist between the periodontal and pulpal tissues in the fully developed tooth. In the apical region this can create a delta of tributaries projecting from the main canal that exit the root as multi- ple foramina. The root canal becomes narrow- est approximately 1.0-1.5 mm from the main foramen. This point is known as the apical constriction, and lies just prior to the layer of cementum that covers the root. The position of such a constriction is variable and not visi- ble on a radiograph, and can be completely destroyed by inflammatory resorption. It is therefore impossible for clinicians to estimate this point by tactile methods alone, and this confirms the need for other methods, for example an apex locator and a radiograph, to try to estimate root canal length during endodontic treatment. A tooth may have sev- eral apical, accessory and lateral canals. Lateral canals are also present in the furcation region of some molar teeth. The presence of a lateral canal can sometimes be seen radiologi- cally when the root canal system is infected, because breakdown products within the lat- eral canal cause inflammatory responses in the periradicular tissues, leading to a lateral radi- olucency on the radiograph. The integrity of the existing apical constriction should be maintained during root canal preparation. Studies have shown that the average distance

Periodontal ligament The periodontal ligament is a fibrous connec- tive tissue. Fibres run in specific groups: gin-

Table 2.1 Three-dimensional root canal anatomy three dimensions it has a shape somewhat sim- ilar to a baseball glove. The constriction cannot always be seen radiologically. Coronally, the root canal is wider buccopalatally, with an oval cross-sectional shape; it becomes circular at the apex. With age the roof of the pulp chamber recedes and the canal appears much narrower on clinical radiographs. This can be deceptive, because buccopalatally the canal may still be much wider, and in three dimen- sions the canal is more ribbon-shaped. Clinical Points

Lateral incisor teeth are generally shorter than maxillary central incisors, and have an aver- age length of 21 mm. There is usually only one canal, with an average mature pulp space volume of 11.4 mm3. Developmental anom- alies such as dens invaginatus are sometimes seen. Pulp horns are more marked than in central incisors, and the incisal outline of the pulp chamber tends to be more rounded than that of central incisors. The apical region of the root canal is often curved in a palatal direction.

Figure 2.9 These young maxillary incisors have wide pulp chambers.

thirds. Maxillary first premolars with three roots have been reported; and these usually show a similar morphological arrangement to maxillary molars. Generally, the average length of the first premolar is 21 mm and the average pulp volume is 18.2 mm3. The pulp chamber is wider buccopalatally, with two pulp horns. The chamber appears much narrower on radiographs. Root canal orifices lie buccally and palatally. With age secondary dentine is deposited on the roof of the pulp chamber. The root canals are usually fairly straight, divergent and round in cross-section. A maxillary first premolar with two canals. Clinical Points

Figure 2.16 In this maxillary second premolar the single root canal has a 'ribbon-like' shape.

Figure 2.14 A maxillary first premolar with three canals, these are orientated in a similar manner to the maxillary first molar.

The maxillary first molar is generally three- rooted, with three or four canals. The mesiobuccal root contains two canals in approximately 60% of cases. The two canals in the mesiobuccal root are usually closely interconnected and sometimes merge into one canal or can be joined by a fin. The average length of this tooth is 21 mm, and the average pulpal volume 68.2 mm3. The bulk of the pulp Clinical Points

The maxillary first molar can have very curved mesiobuccal roots.

Figure 2.21 A maxillary first molar with three canals.

Figure 2.19 Gaining access to the second mesiobuccal canal can best be achieved from a posterior aspect, aiming the file tip mesially.

Figure 2.23 In this case the two mesiobuccal canals are separate, but there is an interconnection in the mid-third of the root. The mesiobuccal canals are often curved, and can be dif- ficult to negotiate.

Figure 2.26 Mandibular incisors. Mandibular incisor canal configurations.

Mandibular Canine (Figs. 2.29, 2.30) This mandibular canine has two canals. This tooth bears a striking resemblance to the maxillary canine, but is smaller, with an aver- age length of 22.5 mm and an average mature pulp volume of 14.2 mm3. This tooth usually has one root and one canal, but can occasionally have two (14%). The pulp chamber is pointed coronally, and there can be a cervical constric- tion. Coronally the root canal is oval in cross- section, becoming round in the apical region.

This tooth usually has two roots, which have average lengths of 21 mm and an average mature pulp volume of 52.4 mm3. The pulp chamber is quadrilateral in cross-section at the level of the pulp floor and is wider mesially than distally. There may be four or five pulp horns. The distal root tends to be more rounded than the mesial root, which has a kidney bean shape in cross-section at the mid-third. There are usually two canals in the mesial roots and one in the distal. Approximately a third of distal roots contain two canals. The two mesial canals merge in approximately 45% of cases to a single fora- men. The single distal canal is ribbon-shaped and has its largest dimension buccolingually. The mesiobuccal canal is generally curved, and often exits the pulp chamber in a mesial direction, while the mesiolingual canal tends

Figure 2.38 In this mandibular molar the canals are highly curved and there are many interconnections. The distal canal divides into two canals in the apical third.

Figure 2.37 A mandibular first molar with four separate canals, two in each root.

In Caucasians the mandibular second molar is similar to the mandibular first molar. Root Mandibular second molar.

Figure 3.4 A molar tooth with active caries, which is lighter in colour. There is now consensus amongst clinicians that during cavity preparation soft carious dentine at the amelodentinal junction and over the pulp should be removed. When preparing deep carious lesions in vital teeth clinicians find it difficult to know when to stop excavation. If pulp exposure can be avoided then root canal treatment may often be unnecessary in a tooth free of signs and symptoms. There is, however, no justification

Figure 3.2 A radiograph showing a reasonable root canal treatment but poor coronal seal (arrowed).

Figure 3.3 Leaking restorations do not provide a good coronal seal. The buccal margin of this full crown restoration has a marginal deficiency (arrowed) that could allow coronal leakage during root canal treatment if an access cavity were cut through the occlusal surface. It would be better in this case to remove the crown before root canal prepa- ration and recement it temporarily between visits.

Figure 3.5 A probe can be used to test the hardness of caries. Mechanical rotary techniques are the most widely used for caries removal. Carious den-

Histological section of advancing caries and correspond- ing diagram. The pulp is remarkably resilient to irrita- tion by micro-organisms. No focus of inflam- matory cells is seen in the pulp until caries is within 1 mm, and only mild inflammation is seen microscopically when the advancing car- ious lesion is within 0.5 mm (Fig. 3.8). This is because the pulp dentine complex is able to protect itself from irritants by the mecha- nisms of tubular sclerosis and irritation den- tine. When bacteria invade the irritation dentine severe inflammatory changes are seen in the pulp. Therefore if infected dentine is removed and the cavity is then sealed, the majority of pulps will survive. Bacterial leak-

Caries removal is carried out prior to the placement of a restoration. The pulp will pro- tect itself from microleakage by tubular scle- rosis (Fig. 3.9), formation of irritation dentine and inflammation; but measures need to be taken to prevent pulp damage before these biological processes have taken place. Lining the cavity for reasons of thermal protection or to prevent material irritation is unnecessary. Dentine has good insulation properties, and few restorative materials are irritant. Most of the original work on material irritancy has now been shown to be due to bacterial leak- age and not to the materials themselves. Linings are therefore principally required to prevent bacterial leakage.

Figure 3.10 Modern composite resins placed following total etch procedures bond well to hydrated dentine, using primer and bond systems (Figs. 3.11-3.13). Calcium hydroxide liners are now rarely advocated to protect the dentine; A reinforced zinc oxide eugenol cement such as IRM (Intermediate Restorative Material: Dentsply, Weybridge, Surrey, UK) is extremely useful in endodontics. The eugenol content is antibacterial.

Addition of bonding agent to etched surfaces. These should not be over-dried. Composite is added in layers.

Figure 3.11 A cracked tooth with a crack running mesiodistally through the crown.

Figure 3.15 A fractured tooth with a longitudinal fracture (arrowed) in the root.

A severe cuspal fracture; root canal treatment and crown lengthening may be required. A subsequent crown will be required to prevent vertical root fracture. A cuSpal fracture; the tooth can be restored with filling material.

Figure 3.16 (Fig. 3.15). The latter involves movement of the two or more fragments, radiological signs, or bone loss associated with the root defect. Heroic attempts have been made to bond together lon- gitudinally fractured teeth; however, the long- term prognosis is poor and extraction is usually the only treatment (Figs. 3.16-3.18).

Figure 3.23 A fractured first molar tooth that requires placement of an orthodontic band prior to root canal treatment.

Zinc phosphate cement is placed on the band prior to seating. Excess cement is carefully removed.

The margins are polished with an abrasive rubber cup. A well-fitting orthodontic band in place on a mandibular first molar.

Figure 3.25 The cavity in the banded tooth is filled with glass ionomer. Seating the band using an amalgam plugger.

A simple metal shell crown filled with zinc oxide and eugenol cement has been used to seal an endodontically treated tooth prior to permanent restoration. The margins are supragingival and smooth, ensuring good periodon- tal health.

Figure 3.29 The crown on the first molar has gross caries under the distal margin that will compromise coronal seal during root canal treatment.

Figure 3.31 The crown is cleaned and filled with glass ionomer.

The crown is replaced. Rubber dam can be fitted more easily and an access cav- ity cut through the crown.

Figure 3.30 The crown was partially split and then elevated and the caries removed.

Figure 3.36 A flat plastic inserted under the margin of a crown to remove it.

Figure 3.35 An ultrasonic tip for vibrating posts and crowns.

Figure 3.40 The Kavo pneumatic crown and bridge remover.

This crown has been sectioned prior to removal.

The tip of the crown tapper is inserted under the margin.

Figure 3.39 The crown tapper being used to remove a bridge. Bridge Abutments

Placing a probe under a bridge to check retention.

Sectioning a bridge. The maxillary right second premolar is the post-retained distal abutment for a three-unit bridge. The tooth requires root canal retreatment. The entire bridge could be removed in order to gain access. Alternatively, the bridge could be sectioned. In this case, the bridge was cut through mesial to the maxillary first premolar.

Long-term provisional restorations for a complex restora- tive case.

The retention form of the crown preparation can be improved greatly with the use of seating grooves.

Different colours, sizes and grades of rubber dam are available.

Well-placed rubber dam aids endodontic treatment.

K clamp (Dentsply, Weybridge, Surrey, UK).

14 clamp (Hygenic, Akron, OR USA). EW clamp (Dentsply).

Table 4.1 Rubber dam clamps placed in groups according to catalogue letter and equivalent number

A multihole punch. The mandrel of a multihole punch.

Adjusting rubber dam forceps with a carborundum disc.

Figure 4.18 Wedgets (arrowed) used to secure a split dam. \ strip of rubber (arrowed) used to secure the mesial end of a multi-tooth isolation.

Various caulking agents have been marketed to help seal around rubber dam. Oraseal putty (Ultradent, South Jordan, UT, USA; Fig. 4.19) and caulking are examples. For larger deficiencies or in the absence of a commercial caulking agent Cavit (ESPE, Seefeld, Oberlay, Germany) or Kalzinol (Dentsply) are useful.

Figure 4.21 The sheet is secured along one side of the frame with light tension.

Figure 4.20 A'U' style frame and rubber dam sheet. The process is repeated on the opposite side.

The bottom of the rubber dam sheet is then looped over the end of the frame, thereby fixing this side.

The rubber dam can be pre-assembled and laid out before use. This speeds up placement (Fig. 4.28).

Figure 4.24 When both sides have been folded a deep gutter is created.

Pushing the overhanging dam back over the corners o' the frame, on one side.

A cross is imagined on the frame and a hole punched in the relevant quadrant. The punch is positioned over the mandibular left quadrant in this picture.

Figure 4.30 The clamp is fitted to the rubber dam to isolate a mandibular right molar.

Figure 4.35 Once the clamp is fully seated the forceps are removed.

Figure 4.37 In this case, sealant has been applied for extra protection. The dam is released from the wings.

Isolation of a mandibular left molar. The forceps are used to carry the dam, frame and clamp to the tooth. The clamp is introduced over the tooth al the clinician's finger.

A clamp has been placed on the most posterior tooth and the dam fitted over the teeth to be isolated.

The mesial aspect of the dam has been retained with a wedget. The edges of the dam are inverted into the gingi- val sulcus and provide a good seal. Knifing dam through a tight contact.

Two holes punched in the rubber dam for a splitdam technique.

Isolation of a bridge using a splitdam technique.

Figure 5.1 A good-quality radiograph of the mandibular first molar which requires root canal treatment. The preoperative radiograph(s) will allow an assessment of basic anatomy: number of roots, size of pulp chamber, fit of coronal restoration, caries, pulp stones, curvature of root canals, likelihood of lateral canals, iatrogenic damage (perforations and frac- tured instruments). When a tooth has been

Access Cavity preparation: ‘lid-off technique’.

Figure 5.3 The depth of the pulp chamber can be estimated from preoperative radiograph.

Table 5.1 Number of roots and canals likely to be encountered in various types of tooth

Figure 5.4 Burs for preparing an access cavity. The J et Beaver dome- ended fissure bur (top: Beavers Dental, Morrisburg, Ontario, Canada) will cut through most restorations. Safe-ended diamond or Endo-Z burs are used to refine the preparation.

Figure 5.7 A carious maxillary molar with pulpal exposure.

Figure 5.6 The access cavity has been modified in order to gain straight-line access to the mesiobuccal canal of this maxil- lary molar. Round burs with different shank lengths (top: standard length bur). Medium- and long-shanked burs are useful in endodontics.

Figure 5.8 The cavity outline is prepared with a diamond bur (541).

Figure 5.11 Remaining carious dentine is removed using a round bur.

The access is refined with the Endo-Z bur. An Endo-Z non end-cutting tungsten carbide bur is inserted into the pulp chamber to remove the '‘lid' of the pulp chamber.

Figure 5.12 The completed access cavity gives straight-line access to all the canals.

Figure 5.13 The pulp floor is generally darker than the walls of the cavity.

Figure 5.15 The access cavities in these maxillary molars have been prepared conservatively but give good straightline access to the root canals. A typical preparation tray of instruments for endodontic treatment (left to right): college tweezers, flat plastic, ball- ended burnisher, amalgam plugger, excavator, DG16 probe, Briault probe, periodontal probe, mirror, number 14 clamp, J et dome-ended fissure bur, Endo-Z bur, fine bore tip for Stropko irrigator.

An ultrasonic tip for removal of dentine on the pulp floor.

Loupes give excellent magnification and illumination.

Location of the second mesiobuccal canal in the maxillary first molar.

Figure 5.22 A lip of dentine has been removed using a round bur to uncover the two mesiobuccal canals (arrowed) in this maxillary molar.

Figure 5.23 Figure 5.24 The location of the two mesiobuccal canals (arrowed) can clearly be seen in this maxillary molar following prepara- tion. tip or a size 2 round bur. There is often an isthmus between the main mesiobuccal canal and the second mesiobuccal (Fig. 5.24); this can be traced until the orifice is located. The pulp floor map should be followed to avoid

Four canals in mandibular molars (Fig. 5.25): Four canals are found in approximately 38% of mandibular molars. If the distal canal does not lie in the midline of the tooth, then a sec- ond distal canal should be suspected. The canals are often equidistant from the midline. In this case the lip of dentine has been removed using ultrasonics to reveal an isthmus (arrowed).

Figure 5.27 Location of the lingual canal in mandibular premolars.

Figure 5.28 A range of Flexofile instruments. The size 20 instrument is being measured using a ruler on the Endoring.

Hedstroem (e.g. Dentsply: Fig. 5.29) files are machined from a tapered cylindrical block. In cross-section they have the appear- ance of a_ series of intersecting cones. Hedstroem files are highly efficient at remov- ing dentine on the outstroke when used in a filing motion, but have poor fracture resis- tance in rotation.

A mandibular molar with unprepared canals and carious exposure of the pulp. The canal is divided into three parts: coronal straight part, middle and apical. In the distal canal in this case the coronal and apical parts converge.

Apical preparation is carried out with hand files or rotary instruments. Coronal flaring is carried out using files, Gates-Glidden burs or orifice shapers. Following coronal preparation the root length is estimated using an apex locator and a radiograph.

The lip of dentine is removed with Gates-Glidden burs during coronal flaring or with special ultrasonic tips, giving better straight-line access. An access cavity has been prepared and the caries removed. There is straightline vision of the canals.

The preparation is completed, creating a gradual taper. This can be produced by stepping back with multiple instruments or by using an instrument with greater taper. Figure 5.33

Figure 5.37 The tip of the apex locator is kept in contact with the file as itis advanced apically.

Two popular apex locators; both work using multiple frequencies and are extremely accurate.

A length-estimation radiograph. The three files in the premolar were not clearly visible and a separate radi- ograph was taken.

If the length radiograph shows that the file tip is more than 3 mm from the apical foramen then the radiograph should be repeated (Fig. 5.39). On some occasions it may also be necessary to take more than one working length radiograph at varying angles. There is no significant difference in the ability to assess root length using digital radiography or conventional film; however, there is a sig- nificant reduction in radiation dose and time with digital radiography.

Figure 5.42 The Balanced Force action. ine technique (hoane et al lyon) This instrumentation technique uses clock- wise/anticlockwise rotational motion to remove dentine with flexible stainless steel files or nickel-titanium files (Fig. 5.42). Itis useful for rapidly removing dentine in curved canals whilst maintaining curvature (files are not precurved). If coronal preparation has been carried out, then there will be less change in the length of the preparation during instrumentation. The lengths are marked on the file with a rubber stop to a clearly definable and easily remem-

Table 5.3 Tapers appropriate for various root canal situations

Figure 5.44 EO eS Se eS SS eee ee Insert a fine Flexofile, such as size 10 or 15, 0.5-1.0 mm short of the apical constriction. This is verified with an apex locator and radi- ograph. Files are precurved to conform to the

Figure 5.46 A sharp curve in a small file can be used to negotiate past blockages.

Figure 5.45 Figure 5.49 Over-use of Gates-Glidden burs in these mandibular incisors has resulted in a wine-bottle effect.

An electric motor and speed-reducing handpiece is essential for rotary preparation techniques.

The Greater Taper rotary range of instruments: an acces- sory file for coronal flaring (left) and then tapers 0.06, 0.08, 0.10, 0.12.

K3 rotary instruments. The first two on the left are used for coronal flaring; the others can be used apically.

Profiles: orifice openers have three bands, 0.06 tapers two bands and 0.04 tapers a single band.

A range of Profile 0.06 taper instruments.

A baby-bottle warmer is probably the easiest means of heating hypochlorite solution. Prolonged heating will inactivate the solution.

Figure 6.1 Household thin bleach is a readily available sodium hypochlorite solution. It is important to check that there are no additives such as perfumes or sodium hydroxide.

Figure 6.3 Iodine in potassium iodide solution can be used as an irrigant. Here it is applied using a dropper.

Figure 6.5 A Monoject syringe, which has a safe-ended tip.

Hand irrigation in a mandibular molar. Figure 6.8

Figure 6.12 The Piezon unit (EMS, Forestgate, Dallas, TX, USA) with an endosonic insert and irrigant bottle. Bevelled needle: irrigant forced apically; there is a risk of extrusion if the needle becomes lodged in the canal.

Figure 6.13 The ultrasonically energized file creates currents of streaming of irrigant within the root canal. Nodes can be seen along this file as it vibrates in air. Endodontic needles are manufactured with a cut- away tip to allow irrigant to pass out sideways and reduce the risk of apical extrusion.

Figure 6.16 Calcium hydroxide paste in a syringe. A corticosteroid/antibiotic paste. An iodoform-based medicament. This may be particu- larly useful in difficult retreatment cases. Calcium hydroxide is antibacterial owing to its high pH. It can be easily inserted into the prepared root canal as a thick paste, and physically restricts bacterial recolonization (Fig. 6.16). Calcium hydroxide, when placed in the root canal for at least 7 days, has been shown effectively to kill most of the pathogens found within the confines of the root canal system, and can be recommended as anantibacterial medicament. Calcium hydroxide will aid the dissolution of organic material remaining in the root canal after preparation. Calcium hydroxide has been shown experimentally to be superior to cam- phorated paramonochlorophenol, camphor-

Bending the needle tip or placing a rubber stop will pre- vent extrusion of the medicament. A file can be used to place the medicament in the canal. The agent should be smeared on the walls of the root canals, and can be carried to the working length by gently rotating the file in an anti-clockwise direction (Fig. 6.21). If it is mixed to a thick paste consistency a plug-

Calcium hydroxide can be placed using a file. The stop indicates the working length; medicament should coat the entire canal.

Figure 6.19 Using a needle to deliver calcium hydroxide paste into the root canals. ee rr! are Probably the ‘easiest way of applying a medicament. Calcium hydroxide prepara- tions come in different concentrations and in different formats. Disposable plastic tips are excellent, as there is no risk of cross-infection (Fig. 6.19). Metal syringe tips must be auto- claved between patients. It is important to place a fine file along the bore of the needle to ensure that the tip does not become blocked.

ia sicalaid aceite aia Great care must be exercised when using spi- ral fillers, as the instrument can bind in the canal and fracture (Fig. 6.22); the direction of rotation must be verified before use. It is per- haps easiest to use spiral fillers by hand; but they do not really offer any great benefit over applying medicament with a hand instru- ment.

Figure 7.5 l'hermoplasticized gutta percha techniques are very use- ful when obturating complex canal shapes. In this case the root canal system has been obturated with Obtura (Texceed Corporation, Costa Mesa, CA, USA).

Gutta percha manufactured to correspond to the Greater Taper files (Dentsply), in tapers 0.06, 0.08, 0.10, 0.12. Accessory gutta percha points in sizes A-D.

The ISO points are manufactured in a wide range of sizes that correspond to the hand files. A customized cone has been rolled on a glass slab.

The spreader should be inserted to within a few millime- tres of the working length at the start of condensation (shown here in a transparent block).

The gutta percha cones are cut off level with the pulp floor using an electric heater tip or hot instrument. Vertical pressure is applied with a cold plugger for sev- eral seconds.

The process is repeated with more accessory cones. An accessory cone is coated in sealer and inserted into the space created by the spreaders. The sequence for lat- eral condensation is the same as before: cold finger spreader first followed by the heated spreader. Gentle lateral forces are used to adapt the cones while cooling.

A cold finger spreader is inserted alongside the master cone and gentle lateral condensation is applied. A heated Spreader is then placed in the space and used to adapt the gutta percha whilst itis thermoplasticized. Spreaders should be removed from the canal when they are cold to avoid displacing the gutta percha. Pressure should be applied to counteract the shrinkage that occurs during cooling. A light coating of sealer is placed on to the walls of the root canal using a hand file, endosonic file or gutta per- cha point.

A cone is selected that corresponds to the apical dimen- sion and taper of the prepared root canal. It is fitted to the working length with tug-back.

Figure 7.21 The ultrasonic thermoplasticized gutta percha is com- pacted into all the canal irregularities of the transparent plastic block.

An endosonic tip can be used to heat the gutta percha.

The completed preparation should be tapered. As the diameter decreases the resistance to flow increases. Keeping the apical preparation as small as practical pre- vents extrusion of filling material.

A light coating of sealer is placed on the walls of the canal, using a hand file, and onto the gutta percha point.

The System B tip is pre-measured. It should fit passively 5-7 mm from the working length. A rubber stop is used to mark the length against a reference point.

The canal is filled to the level of the pulp floor. Each segment is compacted vertically as it cools.

Figure 7.25 The System B plugger has been marked with a rubber stop. Touching the spring on the handle causes the tip to heat up instantly.

Figure 7.26 Machtou pluggers are used to compact the gutta percha following heating.

Figure 7.27 In this case all the gutta percha cones have been fitted before compaction. Gutta percha will often flow between the mesial canals during compaction, and may prevent correct insertion of a second master cone if the canals are obturated individually.

Figure 7.24 If the tip of the gutta percha point is too small it should be trimmed to correspond to the master apical file.

Figure 7.29 Following backfilling the gutta percha is condensed level with the pulp floor.

Figure 7.30 Crinkling of the gutta percha point is often caused by the tip hitting an obstruction.

Loupes with illumination in the direction of sight.

Figure 8.3 The CPR set of ultrasonic tips: 1C is for vibrating posts, 2C and 3C are for work on the pulp floor, and 4C and 5C are for use within the confines of root canal.

Figure 8.4 These Stieghtz forceps have been modified to make the beak thinner.

Figure 8.5 Dissolved gutta percha is being removed on the tip of a Hedstroem file (arrow). Figure 8.7

A typical gutta percha retreatment case. The existing root filling was removed using Gates-Glidden burs and Hedstroem files followed by chloroform wicking. The second canal in the mesial root was located. Following this all the canals were thoroughly disinfected before being filled with gutta percha and sealer.

Figure 8.6 Paper points are used to wick the remaining dissolved gutta percha from the root canals.

A silver point being withdrawn using fine artery forceps.

Figure 8.10 The core around the heads of the silver points being dis- mantled using a CT4 ultrasonic tip. Removing silver points from the apical third is extremely difficult. Two techniques can be

With care itis possible to remove a silver point even when it is broken off at the level of the pulp floor and overextended.

Figure 8.13 The file in this case (A) was removed using a braiding technique; the canal could then be relocated, prepared, cleaned and filled (B).

The post was then removed with a further trephine. The 1CPR tip for vibrating posts ultrasonically.

Space is made around the tip of the post using a Masserann trephine.

Ultrasonics are used to vibrate the post.

The minimal removal of dentine can be seen (arrow).

Figure 8.26 The Ruddle post removing kit. A trephine is screwed onto the post. As the jaws of the post puller open the post is withdrawn from the canal.

Figure 8.25 Post pullers require adequate space for use; in this case a postis being removed from a lateral incisor.

Figure 8.28 The root of this tooth has been perforated (A). The defect lies well within the alveolar bone and should have a bet- ter prognosis for healing following repair (B). A perforation (arrow) that connects with the periodontal ligament via a pocket. The prognosis is guarded. Figure 8.27

Figure 9.1 tive material (IRM: Dentsply, Weybridge, Surrey, UK) packed into the cavity. Zinc oxide and eugenol materials prevent microleakage, since the eugenol is antibacterial. Pressure should be applied to the material as it is set- ting to ensure good adaptation to the wall of the access cavity. The restoration can be polished with a moist cotton wool pellet (Fig. 9.1). Well-adapted IRM temporaries in two maxillary molar teeth, The restorations have been burnished and polished.

Figure 9.3 Zinc oxide and eugenol cement has been packed across the pulp floor, and it seals the entire access cavity.

(A, B) Temporary restorations for sealing the access cavity during root canal treatment.

Figure 9.4 A full crown restoration should have margins resting on at least 2 rnm of sound dentine. As a rough guideline, a full crown restora- tion should have a ferrule of at least 2 mm of sound dentine around the margins for opti- mum retention (Fig. 9.4).

During crown preparation, sufficient buccal reduction of tooth substance is required. Porcelain jacket crowns require a buccal tooth reduction of between 0.8 and 1.3 mm, and can therefore be more conservative on tooth sub- stance than a metal-ceramic crown. Stained dentine and metal posts affect the aesthetic appearance of a porcelain jacket crown; how- ever, they can be placed over cores built up in Porcelain Jacket Crown

Figure 9.10 The Tenax (Whaledent, Mahwah, NJ, USA) titanium post kit (top to bottom): a wax burnout post, aluminium tem- porary post, titanium preformed post and a post drill.

Figure 9.15 An acrylic material such as Duralay (Reliante Dentaman, IL, USA) can be used to create a The post and core in situ on a stone die. The crown mar- gins are on sound dentine.

The Nayyar core is a useful means of restor- ing a molar tooth after root treatment when there is sufficient remaining tooth substance to support the core. Amalgam is packed into the root canals to a depth of approximately 3 mm and into the pulp chamber to give mechanical retention. An adhesive can be used to give extra retention (Fig. 9.17). An amalgam core.

Figure 9.19 The completed core. Crown margins will be on sound dentine.

A custom cast acrylic temporary on a lateral incisor. The margins are well finished and the restoration is polished to improve the aesthetics and to prevent plaque accumu- lation.

The crowns have metal margins for strength.

Figure 10.1 A longitudinal root fracture exposed by a surgical approach.

The outline of a triangular flap for surgery on the maxil- lary left lateral incisor.

The Leubke-Ochsenbein flap 3 days following surgery. A Leubke-Ochsenbein flap.

A rectangular flap for surgery on the maxillary left lateral incisor.

Figure 10.8 A chronic periapical lesion has perforated the cortical plate (arrow).

The Impact Air handpiece; the exhaust is directed away from the surgical site to prevent air embolism. The surgical site after 2 weeks' healing.

A triangular flap sutured with interrupted sutures.

Mineral Trioxide Aggregate root-end fillings in the buc- cal roots of a maxillary first molar.

Pressure is applied to the flap following suturing.

Figure 10.16 In this case the second premolar was nonvital and had both endodontic and periodontal lesions associated with it. The first molar was vital and therefore the origin of the lesion was periodontal; however, elective root canal treat- ment was carried out so that the mesial root could be resected. Correct treatment depends on accurate diag- nosis, which involves thorough examination and testing. Treatment may be endodontic or periodontal, or both. If the prognosis is poor then the clinician must decide whether to pro- ceed with the indicated treatment, whether to extract the tooth or perhaps whether to carry Figure 10.17

A case of internal resorption in a mandibular canine. (A) The patient presented with inadequate root canal treat- ment. (B) The canal system was retreated, irrigated throughly and filled with gutta percha. Internal resorption (Figs. 10.17-10.19) results from inflammation within the pulp. The pulp

Figure 10.22 A cervical resorption defect exposed surgically on the lin- gual surface of a mandibular canine (arrow).

External cervical resorption. The root canal is still visible (arrows in B) superimposed over the defect.

Diagnosis The use of drv dam for isolation.

composite resin, which gives a final coronal seal. The cement should prevent contamina- tion of the pulp if the composite restoration is lost (Fig. 11.3). Alternatively, mineral trioxide aggregate (MTA: Dentsply) may be used in the cavity and the tooth built up with composite resin. This pulp treatment induces formation of a dentine bridge, allowing the pulp to retain its vitality, the tooth to continue to mature and the root to grow (Figs. 11.4 and 11.5).

Figure 11.5 Vitality testing may be unreliable for several months.

Glass ionomer placed over the dressing material to seal the pulpotomy cavity before placement of light-cured composite.

A deep periodontal pocket has developed following trauma; this indicates a poor prognosis.

Figure 11.7 coronal fragment using a sufficiently large access cavity to allow thorough cleaning. A radiograph is taken to assess the length to the fracture line. The canal is gently cleaned with files and irrigated with sodium hypochlorite. Calcium hydroxide is packed to the fracture line and replaced only when its density is seen on a radiograph to be reduced. When a hard tissue barrier has formed at the fracture line, the canal of the coronal fragment may be filled with gutta percha. Alternatively, when the infection is controlled and soft tissue heal- ing has taken place, it may be possible to insert a 'plug' of calcium hydroxide at the fracture line and fill the remaining space with gutta percha (Fig. 11.7). (A) A radiograph of a nonvital maxillary central incisor with a horizontal root fracture. (B) Calcium hydroxide has been inserted to the fracture line. (C) The tooth has been root filled to the fracture line.

Figure 11.8 A tooth that was previously luxated and now shows cal- cification of the root canal.

An avulsed maxillary incisor following its replantation and splinting (A). The tooth filled with calcium hydrox- ide (B). The same tooth showing the completed root fill- ing (C). A successful outcome, 4 years after root treatment (D).

Figure 11.10 An access Cavity for root canal treatment of an immature tooth. The cavity in the composite restoration has been extended to the incisal edge.

Figure 11.11 reference point with a rubber stop. A small amount of calcium hydroxide putty should be put into the root canal and packed down to length (Fig. 11.11). If it is difficult to keep the canal dry because of apical inflammation, the putty will become slurry-like; a paper point should be used to draw water gently from the medicament. This makes it easier to pack the following section of putty. Placing calcium hydroxide in the access cavity with an amalgam plugger before finally packing the material with a root canal plugger.

Nonvital maxillary central incisors in a young boy, aged 9 years (A). Calcium hydroxide has been packed into the canal and remains well condensed as apical growth con- tinues (B). Completed treatment. The pulp space has been obturated with a gutta percha root filling (C).

Advanced inflammatory resorption of a maxillary central incisor (arrows).

Figure 11.16 ENDODONTIC TREATMENT OF MOLAR TEETH IN CHILDREN This invaginated maxillary lateral incisor tooth has been treated by ‘root filling’ the invagination. The pulp of the tooth is vital. From Pitt Ford HE (1998). Peri-radicular inflammation related to dens invaginatus treated without damaging the dental pulp. A case report. International J ournal of Paediatric Dentistry 8: 283-286, with permission. Apical periodontitis may occur in two ways. The pulp space may become infected via the invagination, or the infection may spread from the invagination directly to the peri- radicular tissues without affecting the root canal. In the former case the tooth does not respond to sensitivity testing and root canal treatment should be undertaken in a modifi- cation of the normal method. In the latter case it may be possible to undertake 'root canal' treatment of the invagination without damag- ing the pulp (Fig. 11.16). Complex invagina- tions should be referred to a specialist.

Evagination (arrow) affecting a mandibular second premolar.

Figure 11.18 Talon cusps labially and palatally on a maxillary central incisor.

Figure 12.1 Sealing a corticosteroid dressing into the pulp chamber of a tooth with irreversible pulpitis. The root canals have not been instrumented.

Figure 12.2 Intraligamental infiltration can be useful when anaesthe- sia is difficult to achieve.

Figure 12.6 Pus has stopped discharging. Antibiotics would not be required in this case.

A fluctuant buccal swelling. The root canal system of the maxillary first premolar has been thoroughly cleaned and dressed with calcium hydroxide. The swelling is to be incised.

Figure 12.5 The swelling has been incised; a microsurgical aspiration tip is being used to remove pus.

Signs and Symptoms The tip of an endodontic irrigating syringe.

Measuring the irrigating needle to prevent extrusion of sodium hypochlorite.

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