in brief Cracked syndrome. • Updates and clarifies the definition of the term ‘’, P including an overview of the typically ra Part 1: aetiology and diagnosis associated signs and symptoms of this syndrome complex. C S. Banerji,1 S. B. Mehta2 and B. J. Millar3 • Provides an account of the epidemiology, ti aetiology and diagnosis of the condition, C including a description of available special e Verifiable CPD PaPer clinical tests to form a positive diagnosis. • Details the factors which may influence the prognosis of affected teeth.

Symptomatic, incompletely fractured posterior teeth can be a great source of anxiety for both the dental patient and den- tal operator. For the latter, challenges associated with deriving an accurate diagnosis together with the efficient and time effective management of cases of cracked tooth syndrome are largely accountable for the aforementioned problem. The aim of this series of two articles is to provide the reader with an in-depth insight into this condition, through the under- taking of a comprehensive literature review of contemporarily available data. The first article will provide details relating to the background of cracked tooth syndrome including the epidemiology, patho-physiology, aetiology and diagnosis of the syndrome, together with a consideration of factors which may influence the prognostic outcome of teeth affected by incomplete, symptomatic fractures. The second article will focus on the immediate and intermediate management of cracked teeth, and also provide a detailed account of the application of both direct and indirect restorations and restora- tive techniques used respectively in the management of teeth affected by this complex syndrome.

introDuCtion ‘split tooth syndrome’ have also been The term ‘cuspal fracture odontalgia’ was used synonymously.5 first used by Gibbs in 1954,1 to describe a Patients suffering from cracked tooth condition which is better now known as syndrome (CTS) classically present with a ‘cracked tooth syndrome’ or ‘cracked cusp history of sharp when biting, or when syndrome’. The latter concept was coined consuming cold food/beverages.6 It has by Cameron in 1964,2 who proceeded to been suggested that the symptom of pain define the condition as ‘an incomplete frac- on biting increases as the applied occlusal fig. 1 Shows an example of a tooth with 7 a , where the patient ture of a vital posterior tooth that involves force is raised. A detailed assessment of the initially presented with symptoms of cracked the dentine and occasionally extends to symptoms may reveal a history of discom- tooth syndrome. any delays in instituting the ’. In more recent times the defi- fort that may have been present for several therapy may result in such an outcome, which nition has been amended to include, ‘a months previously. Other symptoms may may happen where there is doubt over the diagnosis of the condition fracture plane of unknown depth and include pain on release of pressure when direction passing through tooth structure fibrous foods are eaten, ‘rebound pain’.8 that, if not already involving, may progress Pain may also be elicited by the consump- as shown by Figure 1. Table 1 provides to communicate with the pulp and or tion of sugar containing substances5 and a summary of the commonly associated periodontal ligament’.3 also by the act of tooth grinding or during signs and symptoms associated with CTS. The term ‘incomplete fracture of poste- the undertaking of excursive mandibular The physiological basis of pain on chew- rior teeth’ is often used interchangeably movements.9 While some patients are able ing has been hypothesised by Brannstrom with that of cracked tooth syndrome,4 to specify the precise tooth from which the et al.10 to be accounted for by the sud- while the terms ‘green-stick fracture’ or symptoms may be arising, the latter is not den movement of fluid present in dentinal a consistent feature. The absence of heat tubules which occurs when the fractured induced sensitivity may also be a feature. portions of the tooth move independently 1Senior Clinical Teacher; 2General Dental Practitioner and Clinical Teacher, 3*Professor, Consultant in Restora- Where the fracture line may eventually of one another. It is thought that the lat- tive , Department of Primary Dental Care, propagate into the pulp chamber (‘complete ter results in the activation of myelinated King’s College London Dental Institute, Bessemer Road, London, SE5 9RW fracture’), symptoms of irreversible A-type fibres within the dental pulp, *Correspondence to: Professor B. J. Millar or apical periodontitis may ensue, while thereby accounting for the acute nature of Email: [email protected] fractures which progress further towards the pain. It has also been suggested that the Refereed Paper the root may be associated with areas of perception of hypersensitivity to cold may Accepted 25 March 2010 DOI: 10.1038/sj.bdj.2010.449 localised periodontal breakdown or at occur as a result of the seepage of noxious ©British Dental Journal 2010; 208: 459–463 worst culminate in vertical tooth fracture5 irritants through the crack, which results

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in the subsequent release of table 1 the commonly presenting signs and symptoms seen in cases of cracked which cause a concomitant lowering in the tooth syndrome (CtS) pain threshold of unmyleinated C-type Sudden, sharp pain on biting/chewing and in some cases on release: ‘rebound pain’ fibres within the dental pulp.11 An alternative hypothesis has been Sensitivity to cold thermal stimuli; in some cases hyper-reactivity to hot/sugary stimuli may also occur proposed, whereby it has been postu- Symptoms may be present for periods ranging from weeks to months lated that the symptoms are caused by the Inconsistent ability to localise the affected tooth alternating stretching and compressing of the processes located within Pain may be elicited by lateral cusp pressure, as evoked by ‘bite tests’ and tooth grinding 12 the crack. Fracture lines may be seen clinically (sometimes upon removal of the restoration), aided by magnification, The aim of this article is to provide an dyes or transillumination overview of the condition of ‘cracked tooth Positive response to vitality tests; exaggerated response to cold thermal stimuli syndrome’, with regards to its epidemiol- Radiographs; usually inconclusive ogy, aetiology and diagnosis. Figure 2 illustrates a tooth which has an incomplete fracture, which was revealed While incomplete posterior tooth frac- upon the removal of an existing silver tures are most likely to be seen to be occur- amalgam restoration. An incomplete tooth ring in teeth which have carious lesions fracture is often difficult to visualise before or contain dental restorations, a study a restoration is removed, but transillumi- by Hiatt13 reported that 35% of the cases nation can be used from different aspects presenting with CTS among their sample to show the presence of an interface within were among teeth which were sound and the tooth (Fig. 3). Tooth fractures can be caries free. a highlighted by the use of stains although Mandibular molar teeth appear to be the this may be difficult to remove and colour most commonly involved teeth by this con- the final aesthetic restoration. dition,13 followed by maxillary premolars and maxillary molar teeth - while mandibu- ePiDemiology of lar premolar teeth seem to be least affected. CraCkeD tooth SynDrome It has been hypothesised that since lower Epidemiological studies of the incidence of first molar teeth are usually the first per- cracked tooth syndrome are conflicting;13,14 manent teeth to erupt into the dental arch, however, it would be appropriate to state they are most likely to be affected by the b that CTS is a condition which generally condition of dental caries, followed by the fig. 2 Shows an example of a tooth which affects adult dental patients, typically in need of subsequent restorative interven- has an incomplete fracture (a) which the age range of 30 to 60 years. While tion.14 These teeth are therefore more likely was revealed upon removal of an existing the results of an early epidemiological sur- to be rendered with large, deep restorations, silver amalgam restoration; (b) the arrows illustrates the path of the fracture line 6 vey by Cameron in 1976 seemed to sug- making them more vulnerable to the proc- running around the mesiopalatal cusp gest that the condition was much more ess of subsequent fracture. It has also been prevalent among female dental patients, proposed that the ‘wedging effect’ inflicted it has since been shown by more recent upon lower first molar teeth from the prom- studies that both sexes seem to be equally inent mesio-palatal cusp of maxillary first affected.15 molar teeth may also be contributory.14 Geursten et al.16 have reported that tooth fractures are a potential major cause of aetiology of CraCkeD in the industrialised world. tooth SynDrome The availability of incidence data on the The aetiology of incomplete fractures of condition of cracked tooth syndrome is posterior teeth is multi-factorial. In an largely lacking. A study by Krell et al.17 article by Guersten et al.14 it is stated that has reported an incidence rate of 9.7% ‘excessive forces applied to a healthy tooth fig. 3 transillumination of cracked cusp showing mesial midline and lingual fractures. among 8,175 patients referred to a private or physiologic forces applied to a weak- the transmission of the light beam has been endodontic practice over a period of six ened tooth can cause an incomplete frac- ‘stopped’ mesio-lingually by the presence of years. It would be logical to assume that as ture of enamel or dentine’. the fracture more patients are retaining their teeth into Lynch et al.18 have subdivided the causes older age incomplete fractures of posterior of cracks into four major causative cat- ‘Restorative procedures’ such as the teeth are more likely to be observed to be egories, hence: ‘restorative procedures’, placement of ‘friction lock’ or ‘self thread- occurring at an even higher frequency in ‘occlusal factors’, ‘developmental condi- ing dentine pins’,19 the non-incremental the future. tions’ and ‘miscellaneous factors’. application of composite resin, excessive

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hydraulic pressure when luting inlays, that the ratio of force on molars, premolars patients referred to specialist endodontists onlays, crowns or bridges5 (in particular and incisors is 4 : 2 : 1 respectively, with with diagnostic uncertainties are eventu- where the restorations may be ‘tight- far higher forces being applied the closer ally diagnosed with incomplete tooth frac- fitting’), can all induce stresses onto the the tooth is to its posterior occlusal deter- tures. The importance of an early diagnosis residual tooth structure culminating in a minant, (the temporo-mandibular joint).29 has being linked with successful restora- possible fracture.20 Likewise, the place- Occlusal interferences on vulnerable cusps tive management and prognosis.35 ment of poor quality dental amalgam can also lead to eventual fractures as may A careful history and assessment of the alloys, the contamination of freshly placed do non-working side occlusal interfer- symptoms, in particular that of cold sen- dental amalgam by moisture and exces- ences.30 The loss of anterior guidance may sitivity and sharp pain on biting hard or sive condensation pressures when plac- also lead to the generation of harmful tough food which ceases on the release ing amalgam may also induce fractures.21 eccentric forces. of pressure, is an important indicator. It is ironic, however, that dentine pins Parafunctional tooth grinding habits Symptoms may vary according to the are often used to restore fractured cusps may also lead to the generation of con- depth and orientation of the crack.4 among teeth which have been lost through siderable occlusal forces, in particular the According to Homewood,36 fractures cracked tooth syndrome. habit of nocturnal , possibly due tend to occur in a direction parallel to Other aspects of ‘restorative practice’ to cortical inhibitors being suppressed dur- the forces on the cuspal incline; thus with which may contribute to crack formation ing sleep, thus allowing greater forces to larger restorations, cracks tend to be more include the excessive removal of tooth be applied.31 superficial and thereby produce fewer tissue during cavity preparation which So called ‘developmental factors’ include symptoms, while with smaller restorations indeed has been shown to significantly the possibility of areas of localised struc- cracks tend to be deeper and closer to the lower tooth rigidity.22 Deep cusp-fossa tural weakness within a tooth, arising as pulp. It has also been suggested that most relationships which arise as a result of a result of the incomplete fusion of areas cracks tend to run vertically (as opposed the over-contouring of restorations may of calcification.13 to horizontally).33 Vertical cracks usually also contribute to the fracture of the non- Morphological factors associated with run in a mesio-distal direction along the functional cusp.5 The preparation of vital the increased risk of cracked tooth syn- occlusal surface and may involve one or teeth to receive MOD amalgam restorations drome include deep occlusal grooves, both of the marginal ridges respectively.33 (with the loss of both marginal ridges) has pronounced vertical radicular grooves or Diagnosis is often complicated by the been shown to significantly reduce rela- bifurcations, extensive pulp spaces, steep fact that several other dental conditions tive cuspal rigidity, on average by 63%.23 cusp angles, prominent mesio-palatal cusps may readily be mis-diagnosed as cracked It has been proposed that a cavity of width of upper maxillary first molars as well as tooth syndrome. Such conditions include: in excess of one quarter of the intercuspal the presence of lingually inclined man- acute , reversible pulpi- distance should be considered to be at an dibular molar teeth, which are thought to tis, dentinal hypersensitivity, galvanic pain increased risk of fracture.24 be the be most likely to suffer the complete associated with the recent placement of Ratcliff et al.25 have estimated that the loss by fracture of both lingual cusps.32 silver amalgam restorations, post-opera- presence of an intra-coronal restoration Under the category of ‘miscellane- tive sensitivity associated with micro- can predispose the tooth to a risk of frac- ous factors’ are included factors such as leakage from recently placed composite ture 29 fold times greater than that of a the effect of lingual barbells; the crack- resin restorations, fractured restorations, healthy, un-restored tooth! Differences ing/crazing of tooth tissue which arises ‘high spots’ or areas of hyper-occlusion in the co-efficients of thermal expansion from the use of high speed rotary instru- from dental restorations, between that of the tooth tissue and restor- ments; erosive and the factor from the process of parafuntional tooth ative material may also have the potential of thermal cycling, which may induce grinding, arising from con- to induce fracture.26 enamel cracks. ditions such as trigeminal and ‘Occlusal causitive factors’; Trucshowksy5 An ageing dentition may also be more psychiatric disorders such as atypical has stated that the most common cause of predisposed to cracking as dental hard facial pain.20 cracked tooth syndrome is that of ‘a mas- tissues become more brittle and less elas- While occasionally cracks may be ticatory accident’ - biting suddenly on a tic with age, whereby forces applied may detected by visual inspection, they are not hard object such as bone with excessive exceed the elastic limits of dentine.7 always readily apparent. The use of mag- force. Other commonly attributing food nifying loupes and trans-illumination with items/objects include betel nut chewing, the DiagnoSiS of the aid of a fibre-optic device (Fig. 3) may inadvertent biting of lead shot, cherry CraCkeD tooth SynDrome be helpful.18 The use of a sharp straight stones and ‘granary’ bread.27 The diagnosis of cracked tooth syndrome probe may also help detect ‘catches’ in the Trauma from the occlusion may also is often problematic and has been known cracks, while the application of the latter lead to fracture. Helkimo et al.28 deter- to challenge even the most experienced of dental instrument at the margins of heav- mined the maximum biting force between dental operators, accountable largely by ily restored teeth which are suspected to natural molars to range from 10 to 73 kg the fact that the associated symptoms tend be involved by an incomplete fracture with an average of 45.7 kg for males and to be very variable and at times bizarre.33 may elicit symptoms of sharp pain should 36.4 kg for females. It has been estimated Indeed it has been reported34 that 20% of a fracture be possibly present. The removal

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of existing restorations may also help to and the patient asked to bite; by the sub- reveal fracture lines. sequent application of the stick to each An un-authenticated technique, which individual cusp in turn it may be possible has often been used by the authors of this to localise the affected cusp. The use of article particularly where there may be cotton wool rolls involves placing the roll doubt over the precise diagnosis, is one on the suspected tooth and requesting the which involves the placement of compos- patient to bite down and then suddenly ite resin over the affected tooth without releasing the pressure. Pain perceived upon etching and bonding; material is added release of pressure has been suggested fig. 4 tooth Slooth (Professional results, uSa) at a minimal thickness of 0.5 mm and by Kruger38 to confirm the diagnosis of wrapped over across the external line cracked tooth syndrome. The use of rubber angles of the tooth onto the axial walls. plungers of anaesthetic carpules suspended of an incomplete fracture of a posterior The set material acts as a splint and the from a length of floss, to be used in a simi- tooth, have been discussed in more detail patient can bite down on this with an lar fashion to cotton wools rolls, to aid in in second of the two articles on cracked intervening bite test; although high, it the diagnosis of cracked tooth syndrome, tooth syndrome. may result in greatly reduced symptoms has also been described.39 as the fracture no longer opens on clench- Commercially available diagnostic tools the PrognoSiS of teeth ing, perhaps confirming the diagnosis of to undertake ‘bite tests’ include products affeCteD by CraCkeD tooth SynDrome an incomplete fracture. It must be empha- such as ‘Fractfinder (Denbur, Oak Brook, sised, however, that there is no evidence in IL, USA) and ‘Tooth Slooth II’ (Professional The prognosis of teeth affected by CTS the available literature (to the knowledge Results Inc., Laguna Niguel, California, is dependent on a multitude of factors. of the authors) to scientifically validate USA). Figure 4 shows the Tooth Slooth The location and extent of the crack is this approach. which comprises two small plastic pyrami- a key determinant. It has been reported The use of stains to highlight fracture dal plastic bite blocks attached to a handle that incomplete cracks generally run in a lines such as gentian violet or methyl- at either end (20 by 10 mm). One block has mesio-distal direction (81.1%); rarely are ene blue33 have been described by several a small concavity at its apex which can vertical or orovestibular cracks seen,41 For authors. However, it is imperative to note accommodate the cusp of a tooth.40 The cracks that are confined to the dentine that the technique of using stains to delin- slooth is placed either between the cusps of layer, that run in a horizontal direction eate cracks may take several days to be a tooth or onto the cusp tip and the patient not involving the dental pulp, or for those effective and may require the placement is asked to close together. Pain on biting fractures which are limited to a single mar- of a provisional restoration in the cavity, or release on the specific cusp identifies ginal ridge which do not extend more than which may further undermine the struc- the offending/involved cusp. Ehrmann et 2-3 mm below the periodontal attachment, tural integrity of the tooth and thereby al.37 have advocated the use of this method the prognosis has been reported by Clark et aid in the process of crack propagation. as one with a higher level of sensitivity al.42 to be ‘excellent’; while the prognosis Another complication with the use of than that associated with the use of wood for fractures that involve both marginal delineation dyes is the subsequent diffi- sticks; furthermore, it is thought to allow ridges, communicating with the dental pulp culty associated with the placement of a for the more accurate identification of the or those fractures that extend vertically definitive aesthetic restoration. Periodontal affected/involved cusp. through the pulp or involve the sub-pulpal probing may also be helpful, as localised Vitality tests for involved teeth are usu- floor has been described as being ‘poor’. isolated periodontal probing defects may ally positive,5 although sometimes affected Affected teeth which present with com- be seen where fracture lines may have teeth may display signs of hypersensitivity plete mesio-distal fractures, or one where extended subgingivally. to cold thermal stimuli due to the presence the fractured segment cannot be removed The use of so called ‘bite tests’18 to mimic of pulpal ; a feature that may or be exposed by gingivoplasty or by an the symptoms associated with incomplete help to confirm a diagnosis of CTS. Teeth alveoplasty procedure, have been described fractures of posterior teeth may also prove affected by the condition are seldom tender as having a ‘hopeless prognosis’.42 helpful. However, it is important to gain to percussion (when percussed apically). Other factors which may impact on the prior consent from the patient as the use Radiographs tend to be of limited use prognosis include the anatomy of the tooth of such a test may cause cuspal fragmenta- as fractures tend to propagate in a mesio- and roots, the previous operative/restora- tion! Objects that have been traditionally distal direction,18 parallel to that of the tive history of the tooth and the functional used for this purpose include: orange wood plane of the film. However, they may be forces applied to the tooth (during both sticks, cotton wool rolls, rubber abrasive of value in detecting more rarely occur- functional and parafunctional activity).18 wheels such as a Burlew wheel or the head ring fractures which may be running in a Early recognition will also help to pre- of a number 10 round bur in a handle of bucco-lingual direction and for excluding vent further cracking, in particular, helping cellophane tape. other dental .20 to avoid propagation of the crack into the The technique for the use of wood sticks The use of copper rings, stainless steel pulp chamber or sub-gingivally. It has been has been described.37 It is advocated that orthodontic bands and acrylic provi- postulated that the loss of pulp vitality will the stick is rested on the suspected tooth sional crowns to confirm the diagnosis have a poor effect on the prognosis of the

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tooth, as endodontically treated cracked 11. Davis R, Overton J. Efficacy of bonded and non- 27. Talim S T, Gohil K S. Management of coronal frac- bonded amalgams in the treatment of teeth with tures of permanent posterior teeth. J Prosthet Dent teeth have been shown to display a rela- incomplete fractures. J Am Dent Assoc 2000; 1974; 31: 172-178. tively high failure rate of 14.5% after an 131: 496-478. 28. Helkimo E. Bite force and functional state of the 43 12. Dewberry J A. Vertical fractures of posterior teeth. masticatory system in young men. Swed Dent J evaluation period of two years. Indeed, it Lieve F S(ed). Endodontic therapy, 5th ed. pp 71-81. 1978; 2: 167-175. has been reported that approximately 20% St Louis: Mosby, 1996. 29. Arnold M. Bruxism and the occlusion. Dent Clin 13. Hiatt W H. Incomplete -root fractures in North Am 1981; 25: 395-407. of teeth with cracked tooth syndrome will pulpal periodontal disease. J Periodontol 1973; 30. Sweptson J H, Miller A W. The incompletely frac- require root canal therapy.44 The skill and 44: 369-379. tured tooth. J Prosthet Dent 1986; 55: 413-415. 14. Geurtsen W. The cracked tooth syndrome: clini- 31. Attansio R. Nocturnal bruxism and its clinical man- experience of the operator are also impor- cal features and case reports. Int J Periodontics agement. Dent Clin North Am 1991; 35: 245-252. tant factors.18 Restorative Dent 1992; 12: 395-405. 32. Bader J D, Martin J A, Shugars D A. Incidence rates 15. Roh B D, Lee Y E. Analysis of 154 causes of teeth for complete cusp fracture. Community Dent Oral Finally, the technique used to manage with cracks. Dent Traumatol 2006; 22: 118–123. Epidemiol 2001; 29: 346-353. the condition will also have an important 16. Geurtsen W, Garcia-Godov F. Bonded restorations 33. Liu H H, Sidhu S K. Cracked teeth – treatment for the prevention and treatment of the cracked rational and case management: case reports. impact on the ultimate prognosis of the tooth syndrome. Am J Dent 1999; 11: 266–270. Quintessence Int 1995; 26: 485-492. affected tooth. The second paper in this 17. Krell K, Rivera E. A six year evaluation of cracked 34. Brady B V, Maxwell E H. Potential for tooth fracture teeth diagnosed with reversible pulptitis; treatment in restorative dentistry. J Prosthet Dent 1981; series will discuss the latter issue in con- and prognosis. J Endod 2007; 33: 1405-1407. 45: 411-414. siderable detail. 18. Lynch C, McConnel R. The cracked tooth syndrome. 35. Agar J R, Weller R N. Occlusal adjustments for J Can Dent Assoc 2002; 68: 470-475. initial treatment and prevention of cracked tooth 1. Gibbs J W. Cuspal fracture odontalgia. Dent Dig 19. Fuss Z, Lustig J, Katz A, Tamse A. An evaluation of syndrome. J Prosthet Dent 1988; 60: 145–147. 1954; 60: 158-160. endodontically treated vertical root fractured teeth: 36. Homewood C I. Cracked tooth syndrome – inci- 2. Cameron C E. Cracked tooth syndrome. J Am Dent impact of operative procedures. J Endod 2000; dence, clinical findings and treatment.Aust Dent J Assoc 1964; 68: 405-411. 27: 46-48. 1998; 43: 217-222. 3. Ellis S G. Incomplete tooth fracture - proposal for a 20. Turp C, Gobetti J. The cracked tooth syndrome: 37. Ehrmann E H, Tyas M J. Cracked tooth syndrome: new definition.Br Dent J 2001; 190: 424-428. an elusive diagnosis. J Am Dent Assoc 1996; diagnosis, treatment and correlation between 4. Geurtsen W, Schwarze T, Gunay H. Diagnosis, 127: 1502-1507. symptoms and post-extraction findings.Aust Dent J therapy and prevention of the cracked tooth syn- 21. Rosen H. Cracked tooth syndrome. J Prosthet Dent 1990; 35: 105-112. drome. Quintessence Int 2003; 34: 409-417. 1982; 47: 36-43. 38. Kruger B F. Cracked tooth syndrome. Letter to the 5. Trushkowsky R. Restoration of a cracked tooth 22. Goel V, Khera S, Gurusami S, Chen R. Effect of cav- editor. Aust Dent J 1984; 29: 55. with a bonded amalgam. Quintessence Int 1991; ity depth on stresses in a restored tooth. J Prosthet 39. Liebenburg W H. Esthetics in the cracked tooth syn- 22: 397-400. Dent 1992; 67: 174-183. drome: steps to success using resin bonded ceramic 6. Cameron C E. The cracked tooth syndrome: addi- 23. Plotino G, Buono L, Grande N, Lamorgese V, Soma restorations. J Esthet Dent 1995; 7: 155-166. tional findings.J Am Dent Assoc 1976; 93: 971-975. F. Fracture resistance of endodontically treated 40. Fox K, Youngson C C. Diagnosis and treatment of 7. Signore A, Benedicenti S, Covani U. Ravera G. molars restored with extensive composite resin the cracked tooth. Prim Dent Care 1997; 4: 109- A 4 to 6 year retrospective clinical study of restorations. J Prosthet Dent 2008; 99: 225-232. 113. cracked teeth restored with bonded indirect 24. Mondelli J, SteagallL, Ishikiriama A. Fracture 41. Mittal N, Sharma V, Minocha A. Management of resin composite onlays. Int J Prosthodont 2007; strength of human teeth with cavity preparations. cracked teeth - a case report. Endodontology 20: 609–616. J Prosthet Dent 1980; 433: 419-422. 2007; 39-44. 8. Stanley H R. The cracked tooth syndrome. J Am 25. Ratcliff S, Becker I, Quinn L. Type and incidence of 42. Clark L L, Caughman W F. Restorative treatment for Acad Gold Foil Oper 1968; 11: 36-47. cracks in posterior teeth. J Prosthet Dent 2001; the cracked tooth. Oper Dent 1984; 9: 136-142. 9. Griffin J. Efficient, conservative treatment of 86: 168-172. 43. Tan L, Chen N N, Poon C Y, Wong H B. Survival of symptomatic cracked teeth. Compendium 2006; 27: 26. Bearn D, Saunders E, Saunders W. The bonded root filled cracked teeth in a tertiary institution.Int 93-102. amalgam restoration – a review of the literature Endod J 2006; 39: 886-889. 10. Brannstrom M, Astrom A. The hydrodynamics of and report of its use in the treatment of four cases 44. Gutman J L, Rauskin H. Endodontic and restorative dentine: its possible relation to dentinal pain. Int of cracked tooth syndrome. Quintessence Int 1994; management of incompletely fractured molar teeth. Dent J 1972; 22: 219-227. 25: 321-326. Int Endod J 1994; 27: 364–365.

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