endodontic new zealand journal. 36 june 2007.pdfanother modifiedbisecting angle technique was...

New Zealand Endodontic Journal Vol 36 June 2007

EndodonticJournalVol 36 JUNE 2007 ISSN 0114-7722

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Contents

2 Editorial Notes

3 Editorial Peter Cathro 4 CommonRootCanalConfigurations Rajneesh Roy

5 X-ray Beam Alignment for Endodontics Abdul Aziz with Particular Relevance to Length Assessment

12 Case Report Rajneesh Roy

15 News from the University of Otago

Front Cover: Talon Cusp

New Zealand Societyof Endodontics (Inc)

PresidentSara JardinePO Box 7788Wellesley StreetAuckland

SecretaryMike Jameson2 Granville TerraceBelleknowesDunedin

TreasurerDeborah CreaghCMC HouseLevel 989 Courtenay PlaceWellington

Journal EditorTina HaumanPO Box 647Dunedin


Editorial Notices

The New Zealand Endodontic Journal is published twice yearly and sent free to members of the New Zealand Society of Endodontics (Inc). The subscription rates for membership of the Society are $35 per annum in New Zealand or $45 plus postage for overseas members. Graduates of the University of Otago School of Dentistry enjoy complimentarymembershipforthefirstyearafter graduation. Subscription inquiries should be sent to the Honorary Secretary, Dr Mike Jameson, 2 Granville Terrace, Dunedin. Contributions for inclusion in the Journal should be sent to the Editor, Tina Hauman, PO Box 647, Dunedin. Deadline for inclusion in theMayorNovemberissueisthefirstdayofthe preceding month. All expressions of opinion and statements of fact are published on the authority of the writer under whose name they appear and are not necessarily those of the New Zealand Society of Endodontics, the Editor or any of theScientificAdvisers.

Information for AuthorsThe Editor welcomes original articles, review articles, case reports, views and comments, correspondence, announcements and news items. The Editor reserves the right to edit contributions to ensure conciseness, clarity and consistency to the style of the Journal. Contributions will normally be subjected to peer review. It is the wish of the Editor to encourage practitioners and others to submit material for publication. Assistance with word processing and photographic and graphic art production will be available to authors.

ArrangementArticles should be typewritten on one side of A4 paper with double spacing and 3cm margins. The author’s name should appear under the title and name and postal address at the end of the article. If possible, the manu-script should also be submitted on computer disc, either Macintosh or PC compatible.

ReferencesReferences cited in the text should be placed in parenthesis stating the authors’ names and date, eg (Sundqvist & Reuterving 1980). At the end of the article references should be listed alphabetically giving surnames and initials of all authors, the year, the full title of the article, name of periodical, volume number and page numbers.

The form of reference to a journal article is:Sundqvist G, Reuterving C-O (1980) Isolation of

Actinomyces israelii from periapical lesion. Journal of Endodontics 6, 602-6.

The form of reference to a book is:Trowbridge HO, Emling RC (1993) Inflammation,

4th edn, pp 51-7. Chicago, USA: Quintessence Publishing Company Inc.

IllustrationsIllustrations should be submitted as clear drawings, black & white or colour photographs and be preferably of column width. Radiographs are acceptable. However a black & white photograph is preferred. Illustrations must be numbered to match the text and bear the author’s name and an indication of the top edge on the back. Legends are required for all illustrations and should be typewritten on a separate page.


Editorial

Once again I am extremely grateful to the post-graduate students for their contributions to the journal. The University of Otago now has seven endodontic post-graduates, which I believeisareflectionofthegeneralimportanceofendodonticsinclinicalpracticeandalsothe quality of the programme being offered. Amissedcanalisoneofthemostcommonreasonsforfailureandthecanalconfigurationchart presented by Rajneesh Roy provides a useful guide when searching for canals. In the rush of a busy day, it is all too easy to accept a tooth has only the canals you stumble upon. Ifyoudon’tlookforadditionalcanalsyoualmostcertainlywon’tfindthem!

Abdul Aziz’s assignment on radiography highlights the need for good paralleling techniques, but also the limitations when determining the working lengths. Endodontics is undoubtedly difficult,anddeterminingwheretheforamenis,canbeparticularlychallenging.

The case presentation by Rajneesh is a good example of how the principles of Cvek’s pulpotomy technique can be used in clinical situations other than trauma.

I thank Tina Hauman for all her help getting this edition of the journal together and also for her willingness to take over the role of editor.

Peter Cathro


Common Root Canal Configurations

Tooth Number of roots Number of canals

MaxillaCentral incisor 1 1Lateral incisor 1 1Canine 1 1 (Carrotte 2004)First premolar 2-3 1 (6%) 2 (91%) 3 (3%)Second premolar 1-3 1 (40%) 2 (59%) (Bellizzi & Hartwell 1985) 3 (1%)

First molar 3 4 (91%) 3 (9%)Second molar 3 4 (90%) (Imura et al. 1998) 3 (10%)

MandibleCentral incisor 1 1 (57%) 2 (43%)Lateral incisor 1-2 1 (55%) (Laws 1971) 2 (45%)Canine 1-2 1 (86%) (Kaffe et al. 1985) 2 (14%)First premolar 1 1 (77%) 2 (23%)Second premolar 1 1 (88%) (Zillich & Dowson 1973) 2 (12%)First molar 2-3 3 (67%) 4 (33%)Second molar 1(22%)-2(76%) 2 (13%) 3 (79%) 4 (8%) (Manning 1990) C-shaped (7%)

BibliographyBellizzi R, Hartwell GR (1985) Radiographic evaluation

of root canal anatomy of in vivo endodontically treated maxillary premolars. Journal of Endodontics 11, 37-9.

Carrotte P (2004) Endodontics: Part 4. British Dental Journal 197, 379-83.

Imura N, Hata GI, Toda T, Otani SM, Fagundes MI (1998) Two canals in mesiobuccal roots of maxillary molars. International Endodontic Journal 31, 410-4.

Kaffe I, Kaufman A, Littner MM, Lazarson A (1985) Radiographic study of the root canal system of mandibular anterior teeth. International Endodontic Journal 18, 253-9.

Laws AJ (1971) Prevalence of canal irregularities in man-dibular incisors: a radiographic study. New Zealand Dental Journal 67, 181-6.

Manning SA (1990) Root canal antomy of mandibular second molars. Part II C-shaped canals. International Endodontic Journal 23, 40-5.

Zillich R, Dowson J (1973) Root canal morphology of mandibularfirstandsecondmolars.Oral Surgery, Oral Medicine, Oral Pathology 36, 738-44.


IntroductionThefirstdentalradiographwastakenbyaGermandentist, Dr Otto Walkhoff, on January 14, 1896. He wrapped an unexposed photographic glass plate in rubber dam and placed it between his tongue and teeth.He then laystillon thefloorandexposedhimself to 25 minutes of very high radiation to get an image. He used this technique on his patients and reported that some began to loose hair from exposed areas. Within two years of this, exposure times in dental radiography were reduced to 9 minutes (Langland & Langlais 1995). A modern X-raymachineexposesthefilmformillisecondsand achieves an acceptable radiograph. The optimal beam size for such an exposure must be less than 6.05 cm in diameter. The focal spot for such beams have been minimised to 0.6-1.2 mm2. The former helps in minimising the unnecessary exposure of healthy tissues and improve the accuracy of beam alignment and the latter enhances sharpness of the radiograph (Langland et al. 2002).

Radiographic diagnosis of periapical conditions (Brynolf 1979), root canal anatomy, canal prepara-tion and obturation are essential to successful endodontics. The use of radiographs is mandatory during root canal treatment to determine the anatomical details, tooth and bone pathology, canal length, quality of obturation and recall assessment for healing (Fava & Dummer 1997). Root canals are well hidden and obstructed by other anatomical structures and/or pathologies. When the apical foramen exits to the side of the root or in a buccal or lingualdirectionitbecomesdifficulttoviewontheradiograph (Forsberg 1987a; Gordon & Chandler 2004). A radiograph is a two dimensional image of a three dimensional object.

Moreover, trauma cases that present to a clinician do not usually have base line records or radiographs for comparison. It has been reported that the mean age of dento-alveolar trauma is 7 (+/- 4.4 yrs) (Gassner et al. 2004). Series of (or any) periapical radiographs for this age group is rare. Apart from

X-ray Beam Alignment for Endodonticswith Particular Relevance to Length Assessment

Abdul Aziz

clinical history and examination, diagnostic radiographs are vital to assess sometimes small but significant injuries aswell as to review thesequelae of trauma.

The head of an X-ray machine can only be manipulated in two planes i.e. horizontal and vertical. The most commonly used technique in the earlier years was a bisecting angle technique.

In 1951, the paralleling technique was introduced (Updegrave 1951) and has been used since extensively. No new technique of beam alignment has been formulated since the introduction of paralleling radiographic technique and it remains the recommended technique (Biesterfeld et al. 1980; Forsberg 1987a, 1987b; Cohn 1988; Bridgman & Campbell 1995; Forsberg & Halse 1997; Chandler & Koshy 2002).

Methods of Beam Alignment Bisecting angle techniqueThe X-ray beam is directed perpendicular to an imaginary line that bisects the angle formed by the longaxisofthetoothandthefilm(Figure1).When

Figure 1: Bisecting angle technique. A – long axis of tooth, B – film held in contact with the tooth and mucosa, C – ima-ginaeey line that bisects the angle formed by A and B. X-ray beam is aligned perpendicular to C (Cohn 1988).


this technique is used with the perfect angulation of thebeamandfilm,thereisstillaninherentproblemwhere the beam passes through the tooth obliquely, so distortion of the image is inevitable (Goaz & White1987).Forsbergfoundtherewasasignificantdifference between the radiographic and clinical length of a wire placed within a root canal. In the same experiment he found that a small variation of 10o vertical angulation improved the ability to determine the correct working length. He noted that the chances of using this technique clinically were limited, due to the anatomy. This may hinder thecorrectofplacementofthefilmaswellasthecorrect beam angulation (Forsberg 1987a). In most of the literature, the use of bisecting angle technique is discouraged (Vande Voorde & Bjorndahl 1969; Biesterfeld et al. 1980; McDonald 1984; Andreasen & Andreasen 1985; Forsberg 1987a, 1987b; Cohn 1988; Bridgman & Campbell 1995; Forsberg & Halse 1997; Chandler & Koshy 2002; Naoum et al. 2003). Nonetheless it has limited use in patients withunusualanatomylikeaflatpalate,disablingconditions that do not allow the patient to bite and, some uncooperative patients (Miles et al. 1993; Bridgman & Campbell 1995).

Barr and Gron described palate contour to be a limiting factor in intraoral radiography (Barr & Gron 1959). They concluded the paralleling technique as more effective for anterior teeth, with anarrowerfilmandthemodifiedbisectingangletechnique being more suitable for posterior teeth withastandardfilm.

Anothermodifiedbisectingangle techniquewasdescribed by Van Aken in 1969 for multi-rooted teeth,wherethefilmisplacedparalleltoonerootand the bisecting angle is directed to the other roots (Van Aken 1969). Theoretically this would allow a paralleling technique for one of the roots and a correct bisecting angle for the other roots. Since paralleling is sometimes difficult thiswill be agood compromise as relatively minimal distortion will occur.

Paralleling TechniqueThefilmisplacedparalleltothelongaxisofthetooth and the beam is directed perpendicular to thefilmandthelongaxisofthetooth(Figure2).This technique has been shown to produce a more accurate image and has better reproducibility (Bean 1969; Van Aken 1969; Forsberg 1987b; Tugnait et al. 2003). It needs to be used in conjunction with an X-rayfilmholderusingalongconetechnique.This

takes the guesswork out of alignment (Bridgman & Campbell 1995; Tugnait et al. 2003). A variation to this technique is to change the horizontal angle mesially or distally. This can be useful to:

• determine the number, location, shape,size and direction of curvature of roots and canals

• identifysuperimposedrootsandcanals• establishthepositionofrootcurvatures• locatethepositionofrootapicesinrelation

to anatomical landmarks• distinguishbetweenanatomical landmarks

and radiolucent apical pathology• establish the position of iatrogenic errors

(perforations, fractured instruments etc.)• distinguish between internal and external

root resorption• locateforeignbodiesfollowingtrauma;• establishthepositionofrootfracturesorre-

sorptive processes (Fava & Dummer 1997)

The authors also state that although altered angles ofbeamalignmentorfilmplacementmayhaveadiagnostic advantage, it alters the normal sharpness and length of the tooth.

Naoum et al (2003) introduced contrast medium into the canal system of mandibular molars and radiographs were taken at 0 degrees and at 30 degrees mesial to the orthoradial beam angulation. Three independent evaluators, using set-criteria, evaluated the mesial root on the radiographs for number of visible canals, visibility of entire canal length, location of canal terminus in relation to the radiographic apex, configuration of canals,

X-ray Beam Alignment for Endodontics

Figure 2: Paralleling technique. Film held parallel to the long axis of the tooth. X-ray beam is sligned perpendicular to the film (Cohn 1988).



level of multi-canal merging and the presence of lateral canals. It was found that the tube shift to 30 degrees without a contrast medium gave less information than the orthoradial (0 degrees) view. It was also found that the use of contrast provided more information on the radiographs at 30 degree beam shift (Naoum et al. 2003).

In contrast, a study carried out by Klein et al (1997) had found that beam shift horizontally 20-30 degrees helped to identify extra canals in mandibular incisors, however no contrast medium was used and different tooth was used.

In all endodontic cases it is recommended that at least two radiographs should be taken at different angles to reveal superimposed and hidden structures (Weissman & Longhurst 1971; Langlais et al. 1979; Biesterfeld et al. 1980; Pratten & McDonald 1996). Forsberg(1987b)comparedtherootfillinglengthusing both the paralleling and bisecting angle techniques. He concluded that even in the hands of an inexperienced dental student, the paralleling technique gave a more accurate and reproducible result. In another experiment, no difference was found between paralleling and bisecting angle technique but the use of paralleling technique was recommended over bisecting due the better re-producibility of images (Forsberg & Halse 1997).

Use of Bitewings in EndodonticsIt has been shown that a periapical radiograph does give an accurate view of coronal tooths structure. Apart from the obvious incomplete image on the radiographs of the crown, the restorations tend to mask underlying pathology. The relationship of the pulp to restoration can also be masked in a periapical view. The anomaly occurs due to a slight change in the beam angulation on a periapical radiograph compared to a true parallel in a bitewing radiograph (Degering 1968; Biesterfeld et al. 1980).

CAsE REPoRT: A recent referral from a private practitioner to rootfilltooth46withaperiapicalareaandafullcoverage crown. On examining the periapical radiograph minimal secondary caries was visible beneath the restoration and slight bifurcation involvement (Figure a). Clinical examination confirmedminimalsubgingivalsecondarycariesand bifurcation involvement.

To confirm the extent of the carious lesion and the bifurcation involvement, a bitewing

radiograph was taken. A significantly larger amount of secondary caries and a greater extent of bifurcation involvement were detected than originally envisaged (Figure b). As a result of the bitewing radiograph, this tooth was referred for an extraction. In the absence of the bitewing radiograph, the futility of treatment might only have been discovered as treatment progressed.

Buccal object Rule “When two different radiographs are made of a pair of objects, the image of the buccal object moves, relative to the image of the lingual object, in the same direction that the X-ray beam is directed” (Richards 1980). The mnemonic derived from this is SLOB (same lingual opposite buccal); the lingual object will always remain at the same side as the tube and the buccal object will move opposite to the tube shift. The technique is useful to shift roots and/or anatomical structures like the zygomatic arch to allow visualisation of the radiographic apices for a

Figure a (above) and b (below). Radiographs courtesy of Dr Artika Patel, postgraduate endodontics doctorate student, University of Otago.


correct working length determination (Gutmann & Leonard 1995). The technique involves exposing afilmat theorthoradial (0o) and another with a horizontal tube shift of 20-30o to separate roots or a vertical tube shift of 20-30o for awkward anatomical or pathological structures (Richards 1980; Gutmann & Leonard 1995).

Beam Aiming Devices andFilm HoldersThe firstX-ray holder(s) in dentistrywere thefingers of dentists or their patients (Pitts 1984).By the early 1900’s methods and devices were developed to standardise the alignment of X-ray source,subjectandfilm.Manyofthefilmholdersthat are used today were invented 50-75 years ago(Dixon&Hildebolt2005).Someofthefilmholders for endodontics include, Snapex, Rinn, Endoray,Unibite,EZ-gripandtheCrawfordfilmholder system. Andreasen & Andreasen (1985) looked retrospectively at the radiographic length of teeth. Radiographs of twenty that were taken prior to the use of aiming devices (1965) of a non-injured tooth were compared to 20 radiographs of the same teeth taken with the use of beam aiming device. The average discrepancy in the length of a tooth was approximately 6.9% when an aiming device was not used. The discrepancy was reduced to2.0%withuseoffilmholdersandaimingdevice.This 2.0% was almost cancelled out when the intra-examiner error of 1.2% was taken into account. The bisecting angle technique was used in both instances.

Radiographic Length AssessmentThe radiographic apex is the tip or end of the root as determined radiographically; it’s location can vary from the anatomic apex due to root morphology and distortion of the radiographic image (American Association of Endodontists 2003).

Agoodperiapicalfilmisdescribedasonethathasthetoothtobetreatedpositionedcentrallyonthefilmwith a minimum 2 mm of periradicular tissue visible beyond and around the radiographic apex (Pitt Ford 2005). The most commonly utilised radiograph in endodontics is the periapical radiograph. The technique involves the radiographic exposure of toothwithaninstrument(usuallyrootcanalfiles)placed within the canals at an approximate length (Forsberg 1987a). Using averages from anatomical studies and the assumption that the cemento-dentinal junction (CDJ) occurs at the apical constriction has

led to the common teaching practice of determining working length to be 1-2 mm short of the anatomic apex as seen on a radiograph (Gordon & Chandler 2004). The understanding of the apical anatomy is invaluable to appreciate the concept of working length (Figure 3). Kuttler (1955) examined the topography of the root canal foramen and the CDJ. He found that the distance from the radiographic apex and the CDJ was 0.5 mm in 18-25 year olds and 0.7 mm for patients older than age 55.

Dummer et al (1984) also examined the apical canal constriction and apical foramen on extracted teeth. The findings indicated that the position and topography differs between different teeth. Apicalconstrictionisclassifiedinto4typesA,B,C, D (Figure 4). Type A is the traditional single constriction, type B is tapering constriction, type C is multi-constriction and type D is parallel constriction.Afifth type has been described asone that will have cementum totally obliterating the foramen (type E) (Gutmann & Leonard 1995). These results indicate that a single assumption of working length to be set at 1mm is not applicable


Apical constriction (CDJ)(minor diameter)

Apiocal foramen (PDL)(greater diameter)

Radiographic apex

0.5-0.7mm

0.5-0.7mm0.5-0.7mm

0.5-3.

0mm

Figure 3: Root apex. Diagram of a root apex depicting the relationship of the cementodentinal junction to the root apex and the apical foramen.

Figure 4: Diagrammatic representation of the variations that can exist in the anatomy of the apical constriction. type A – single constriction, type B – tapering constriction, type C – multiple constrictions, type D – parallel constriction, and type E – constriction blocked by cementum (Gutmann & Leonard 1995).



to all the types of apical foramen. The result will be an under or over-prepared canal. The exact determinationofthepositionofthefiletiportheactual root canal length is only possible if the teeth are histologically examined after extraction (Wrbas et al. 2007). In endodontics this is clearly impractical.

Accuracy of Radiographic Working LengthsDespite the angulation or technique utilised to achieve a radiograph, it still remains a two dimensional representation of a three dimensional object. Radiographs give little or no information on the curvature of the root or the exact location of the apical foramen, because anatomical apex and the apical foramen are seldom the same (Burch & Hulen 1972; McDonald 1992). Birch and Hulen (1972) found that the frequency of deviation of apical foramen from anatomical apex, ranged from 78% in maxillary incisors to 98.9% in distal root of mandibular molars. This highlights the inconsistency of the working lengths derived solely from radiographs.

An error of around 5% is reported in the root canallengthmeasuredonafilmexposedusingaparalleling technique due to the divergence of the rays due the distance (Vande Voorde & Bjorndahl 1969; Forsberg 1987a; Cohn 1988). Therefore on a tooth that is 20 mm long will already have an inherent length disparity of 1mm.

Olson and colleagues (1991) found that when placingfilestotheforameninextractedteeth,only82% appeared to be at the apical foramen with radiographs taken with a paralleling technique. There was no significant difference in results between the teeth radiographed in the alveolus of dried jaw specimens and extracted teeth when the radiographs were evaluated under a stereomicroscope (Olson et al. 1991)

ElAyoutietal(2001)measuredfilesadjustedtothefinalworkinglength,located0to2mmshortof the radiographic apex. These were compared with the actual reference length representing the distance between the apical foramen and the coronal reference. Instrumentation beyond the apical foramen occurred in premolars in 51% of the cases, in molars in 22% and in anterior teeth in no case. These results suggest that in premolars and molars a radiographic working length ending

0 to 2mm short of the radiographic apex provides a basis for unintentional over-instrumentation. A year later a repeat experiment found that the radiographic working length determination resulted in overestimation in 51% of premolar root canals, althoughthemeasuringfiletipwaslocatedtobe0to 2 mm short of the radiographic apex. (El Ayouti et al. 2002). In a survey of Flemish dentists it was reported that 76%of root canalsfilledwerebetween0.5mm-2mm short of the radiographic apex. The majority of the practitioners (39%)filled towithin 1mmof the radiographic apex. A reason for the choice of working length of was a rule of the Belgian health insurance authority stating that root canals ‘‘mustbefilledminimallyupto1mmshortoftheradiographically visible end of the root canal’’, which must be substantiated by a radiograph which the patient has to furnish to the insurance company prior to reimbursement (Slaus & Bottenberg 2002).

Clinical UseIn a survey of radiographic practices in New Zealand in 2000, Chandler and Koshy reported that only 66.7% of dentists took a radiograph for working length all the time. Another 18 % of the practitioners took radiographs in most cases. Interestingly 1.1% of the respondents did not take this view at all (Chandler & Koshy 2002). In a survey of graduates from Cardiff (Wales) found that 89% of dentists took a working length view (Tugnait et al. 2003). In a survey from Turkey, the most preferred technique for periapical radiography was the bisecting angle technique (62%). The paralleling technique was reported from 30.6% and the remaining respondents (7%) did not know the technique they used. Only 69 (11.7%) respondents reported usingfilmholders for theparalleling technique (Ilguy et al. 2005).

Electronic Apex Locators (EAL)Variable results have been published concerning the accuracy of apex locators. Brunton et al (2002) using extracted teeth found the EAL was accurate 100% of the time compared to 60% for radiographs in determing a position within 0.5 mm of the anatomical apex. Pommer (2001) measured the distance between the file tip andthe apical constriction of extracted teeth using a microscope. In 77.2% of the evaluated radiographs the determined apical point of working length was


found in a range of +/-0.5 mm from the apical constriction compared to 98.5% for the EAL - the distancebetweenfiletipandtheapicalconstrictionbeing less than 0.5 mm. An in-vivo experiment showed the accuracy of EAL at approximately 82% and radiographs were accurate in 71% of the cases in determining the correct working length (Hoer & Attin 2004). Modern apex locators have been shown to be accurate in over 90 % of cases (Gordon & Chandler 2004).

summaryMany authors have accepted that the beam angulation technique required for an accurate diagnostic radiograph is the paralleling method (Vande Voorde & Bjorndahl 1969; Biesterfeld et al. 1980; McDonald 1984; Andreasen & Andreasen 1985; Forsberg 1987a, 1987b; Cohn 1988; Bridgman & Campbell 1995; Forsberg & Halse 1997; Chandler & Koshy 2002; Naoum et al. 2003).

The bisecting angle technique has been suggested in its modified form only when a paralleling technique is not applicable (Van Aken 1969; Monsour 1986; Bridgman & Campbell 1995). Both the techniques have shown some degree of distortion. This distortion is considered to be far greater in the bisecting angle technique than the paralleling technique (Van Aken 1969; Bridgman & Campbell 1995; Naoum et al. 2003; Tugnait et al. 2003).

Radiographs remain a two dimensional shadow of a 3-dimensional object. It is recommended that at least two exposures be made (Biesterfeld et al. 1980; Fava & Dummer 1997). Multiple exposures allow utilisation of the buccal object rule and triangular scanning technique. The use of beamaimingdevicesandfilmholdersarewidelyrecommended for accuracy, reproducibility as well as standardising the radiographs (Biesterfeld et al. 1980; Andreasen & Andreasen 1985; Cohn 1988; Dixon & Hildebolt 2005). Radiographs or EAL alone do not accurately establish the correct working length of root canal(s) (Martinez-Lozano et al. 2001). Nevertheless radiographs remain the single most unique tool to peer into the hidden corporeal structures. For root canal length measurement it should be complemented by electronic apex location.

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Pitt Ford TR (2005) Hartys endodontics in clinical practice, Fifth edn; London: Wright.

Pitts NB (1984) Film-holding, beam-aiming and collimating devices as an aid to standardization in intra-oral radiography: a review. Journal of Dentistry 12, 36-46.

Pommer O (2001) [In vitro comparison of an electronic root canal length measuring device and the radiographic determination of working length]. Schweizer Monatsschrift fur Zahnmedizin 111, 1165-1170.

Pratten DH and McDonald NJ (1996) Comparison of radiographic and electronic working lengths. Journal of Endodontics 22, 173-176.

Richards AG (1980) The buccal object rule. Dental Radiography & Photography 53, 37-56.

Slaus G and Bottenberg P (2002) A survey of endodontic practice amongst Flemish dentists. International Endodontic Journal 35, 759-767.

Tugnait A, Clerehugh V and Hirschmann PN (2003) Radiographic equipment and techniques used in general dental practice: a survey of general dental practitioners in England and Wales. Journal of Dentistry 31, 197-203.

Updegrave WJ (1951) The paralleling extension-cone technique in intraoral dental radiography. Oral Surgery, Oral Medicine, Oral Pathology 4, 1250-1261.

Van Aken J (1969) Optimum conditions for intraoral roentgenograms. Oral Surgery, Oral Medicine, Oral Pathology 27, 475-491.

Vande Voorde HE and Bjorndahl AM (1969) Estimating endodontic “working length” with paralleling radiographs. Oral Surgery, Oral Medicine, Oral Pathology 27, 106-110.

Weissman DD and Longhurst GE (1971) Clinical evaluation of a rectangularfield collimating device for periapicalradiography. Journal of the American Dental Association 82, 580-582.

Wrbas KT, Ziegler AA, Altenburger MJ and Schirrmeister JF (2007) In vivo comparison of working length determination with two electronic apex locators. International Endodontic Journal 40, 133-138.



An 11-year old male was referred to the endodontic postgraduate clinic at University of Otago’s School of Dentistry for management of a talon cusp on tooth 21.There were no symptoms associated with the tooth. The talon cusp was detected by the school dental nurse, who referred him to the School of Dentistry for management. He was treated in the paediatric clinic with selective grinding of 1mm of the cusp and Duraphat application. The patient was referred to the endodontic post graduate clinic for further management. The patient was fit and healthy and had no known drug allergies.

Extraoral examination revealed no significant findings. Intraoral examination revealed a large talon cusp on the palatal surface of tooth 21 (Figure 1). Upon occlusion, the talon cusp was in contact with the incisal surface of tooth 31. Tooth 21 responded to cold test within normal limits. There was no tenderness on percussion.

Case Report

Radiographic examination showed normal periodontal ligament space and intact lamina dura around the root of tooth 21. A small strand of pulp extended into the talon cusp (Figure 2). After discussion with the patient’s mother, it was decided to excise the talon cusp and do a Cvek pulpotomy followed by pulp capping and a composite restoration. This approach was preferred over the more conservative one of selective grinding due to the potential risk of undiagnosed pulp exposure leading to necrosis of the pulp and periapical pathology.

The treatment was carried out under local anaesthesia. Buccal infiltration of Scandonest 2% with adrenaline was administered. Rubber dam isolation was achieved. The talon cusp was removed using a high-speed handpiece and diamond bur. A point pulp exposure was seen. This was widened to accommodate the diamond bur and pulp tissue was removed to a depth of mm (Cvek pulpotomy) (Figure 3). The bleeding was arrested

using a plain cotton pellet with pressure. The stump was capped with hard-setting calcium hydroxide cement (Dycal). Glass ionomer lining was placed and the access cavity restored with composite resin (Figures 4 and 5).

The patient was recalled after six months. There were no clinical symptoms and the tooth responded normally to sensibility testing. The radiograph


Case Report

showed intact lamina dura and normal ligament space. The patient will be followed up at six-monthly intervals for a period of four years.

DiscussionPreviously, dens evaginatus and talon cusp were treated as separate anomalies, based on tooth location, but now talon cusp is considered to be a subset of dens evaginatus (Uyeno & Lugo 1996).

Dens evaginatus is a dental anomaly thought to develop during the morphodifferentiation phase of tooth formation (Cameron & Widmer 1997). It is caused by proliferation and evagination of part of the inner enamel epithelium and dental papilla into the stellate reticulum of the enamel organ during tooth development (Tratman 1949). This creates a tubercle of enamel and dentine containing a horn of pulp tissue. This condition is thought to be the reverse of dens invaginatus, which is probably caused by an invagination of the enamel organ.Dens evaginatus is most commonly reported in premolars, but can also occur in molars, canines and incisors (Lau 1955).

Talon cusp is described as a cusp-like structure projecting from the cingulum area of maxillary or mandibular incisors that resembles the talon of an eagle (Pledger & Roberts 1989). The reported prevalence of talon cusp ranges from 0.17% to 7.7% (Chen & Chen 1986; Salama et al. 1990).

The primary dental complication of dens evaginatus is fracture or wear of the cusp leading to pulp exposure, pulpal necrosis and periapical infection (Chen 1984). Other complications include an open apex due to pulp necrosis prior to completion of root formation, interference with the eruption of the tooth, displacement of teeth, and caries in the grooves and fissures surrounding the tubercle.

Various treatment methods for dens evaginatus have been reported in the literature. Oehlers and colleagues attempted to treat dens evaginatus by careful grinding to stimulate secondary dentine formation, with variable results (Oehlers et al. 1967). The authors concluded that this was an unreliable method of treatment.

In another study, thirty nine vital and asymptomatic teeth were treated by removal of the dens and pulp capping with calcium hydroxide. The whole procedure was performed under rubber dam. Subsequently the patients were followed up for thirty months. All the teeth remained vital and asymptomatic (Yong 1974).

Recently, MTA has been used for treatment of dens evaginatus (Koh et al. 2001). MTA has a good sealing capability, biocompatibility and lack of solubility in water. These properties make it suitable for use in treatment of dens evaginatus.

BibliographyCameron A, Widmer R (1997) Handbook of Pediatric

Dentistry, pp 179-81, Mosby, London.Chen R (1984) Conservative management of dens evaginatus.

Journal of Endodontics 10, 253-7.Chen R, Chen H (1986) Talon cusp in primary dentition. Oral

Surgery 62, 67-72.Koh ET, Pitt Ford TR, Kariyawasam SP, Torabinejad M (2001)

Prophylactic treatment of dens evaginatus using mineral trioxide aggregate. Journal of Endodontics 27, 540-2.

Lau T (1955) Odontomes of the axial core type. British Dental Journal 99, 219-25.

Oehlers F, Lee K, Lee E (1967) Dens evaginatus (evaginated odontome): its structure and responses to external stimuli. Dental Practice 17, 239-44.

Pledger D, Roberts G (1989) Talon cusp: report of case. British Dental Journal 167, 171-3.

Salama F, Hanes C, Hanes P (1990) Talon cusp: a review and two case reports on supernumerary primary and


Case Report

permanent teeth. ASDC Journal of Dentistry for Children 57, 147-9.

Tratman E (1949) An unrecorded form of the simplest type of dilated composite odontome. British Dental Journal 86, 271-5.

Uyeno D, Lugo A (1996) Dens evaginatus: a review. ASDC Journal of Dentistry for Children 63, 328-32.

Yong S (1974) Prophylactic treatment of dens evaginatus. ASDC Journal of Dentistry for Children 41, 289-92.


News from The University of otago

At the International Federation of Endodontic Associations 7th World Congress in Vancouver in August:n Darryl Violich, Removal or modification

of smear layer: effect on the Prepometer instrument.

n Rajneesh Roy, Remaining root structure following resection and root-end cavity preparation.

CoNgRATULATIoNstothefourfinalyearMDSinEndodonticspostgraduatestudentswhohavehadresearch abstracts accepted and will present their work at international endodontic meetings.

And at the European Society of Endodontology 13th Biennial Congress in Istanbul in September-n Jack Lin, The optimum electrode placement

site for electric pulp testing of first molar teeth.

n Dikesh Parmar, Fluorescence viability determination of bacteria in dentine.

We wish them well with their travels.

WelcomeThe Department of Oral Rehabilitation would like to welcome three new students to the three year

programme leading to the Doctorate in Clinical Dentistry in Endodontics.

Abdul Aziz graduated from Otago in 1995 and might be better known to some of his classmates as Rohit Prasad. On graduating Abdul worked for two years in Dargaville before moving to Australia. He then spent 4 years in Townsville before moving to Brisbane.

Shalin Desai graduated from Pune University, India, in 2000. He worked for 3 years there before moving to Australia. He completed his ADC registration exams and also studied for a Diploma in Public Health from the University of New South Wales.

Artika Patel graduated from Otago in 2004. Since then she has worked in hospital posts in and around Sydney.

Great news to ‘poach’ dentists from Australia, and good luck to all with their studies.


NOTICE OF MEETING

The Annual General Meeting of the

NEw ZEaLaND SoCIETy of ENDoDoNTICS

will coincide with the NZDA Regional Conference in Dunedin.

The AGM will be held on Sunday, 26 August 2007,

at 5.30pm in the St David Theatre Complex,

University of Otago, Dunedin.

NominationsforofficebearersandmattersforGeneralBusiness

should be sent to Mike Jameson, Secretary,

New Zealand Society of Endodontics,

4 Granville Terrace, Belleknowes, Dunedin.

Email: [email protected]

endodontic new zealand journal. 36 june 2007.pdfanother modifiedbisecting angle technique was...

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