internBtKHMjEniio(tontfc/oiimflI(1992)25,150-157

Root fractures in permanent teeth: a clinical review J. A. YATES Department of Orthodontics and Dentistry for Children, United Medical and Dental Schools, Guy's Hospital London, UK

Summary A retro^>ective study ot22 rootfracturesin 21 patients was perfonned. Ten patients were less than 11 years of age, and boys were involved more often than girls. Ten patients had more than one injured tooth, but there was no case of alveolar bBCture. Twenty-one of the t^th were upper central incisors. Only 11 teeth were seen within thefirstweek, so that not all teeth were splinted and not all di^aced teeth were repositioned. Long-term clinical and radiographic review showed that loss of vitality of the coronal pulp could not be reliably detected for at least 1 year. No tooth became abscessed or developed a anus tract, and resorption of bone at the fracture line was observed in only one out offivencHi-vital teeth. Lack of displacement and placing of a ^ i n t increased the chances erf the puip ronaining vital and healing of the fracture occurring with hard tissue. Scl^osis of the coronal pulp occurred mainly when healing was by connective tissue. The apical pulp always remained vital, and there was sclerosis of the apical pulp In almc^ every case. Keywords: dental injuries, root fractures. Introduction Epidemiology Root fractures of permanent teeth are a relatively rare form of injury, occurring In 0.5-7.0% of cases (Andreasen 1981). They are considered to occur most commonly in the 11-20 year age group, and are often associated with fracture of the alveolar process (Andreasen 1981). Frequently, other teeth are injured at the same time (Andreasen 1981). Root fractures are usueilly classified as involving the apical, middle or coronal third of the root. Histology

mobility and the pulp remaining vital (Fig. 1). In many cases, thefragmentsare joined by connective tissue and the tooth behaves as a short-rooted tooth. The pulp in the coronal fragment regains its vitality, but the fragments remain separated by eitherfibroustissue (Fig. 2) or bone (Fig. 3), In 20-40% of teeth the coronai pulp becomes non-vital (Andreasen 1981), although the apical fragment almost always remains vital (Andreasen & HjertingHansen 1967, Jacobsen & Kerekes 1980). The apical root canal frequently scleroses (Andreasen & Andreasen 1988) (Figs 2 and 3). There may also be narrowing of the coronal canal adjacent to the fracture line (Fig. 2), and in some cases the coronal pulp becomes almost completely sclerosed (Fig. 3), particularly when healing of thefractureline is by connective tissue. Factors that affect healing Many studies have shown that the healing of permanent teeth with root fractures is dependent on a number of factors at the time of injury, and also on the subsequent treatment. Factors at the time of the injury which have been shown to affect the prognosis are the maturity of the root canal as determined by the width of the apex (Andreasen et oM 989) and the degree of displacement of the coronal fragment (Andreasen & Hjerting-Hansen 1967, Andreasen et al. 1989). Treatment factors that affect the long-term prognosis include the presence of splinting (Andreasen & Hjarting-Hansen 1967) and the type of splint (Andreasea et al. 1989). The ideal length of time for splinting has not been determined, although it was shown that there was no difference between teeth splinted for less than 2 months and those splinted for more than 2 months (Andreasen & Hjorting-Hansen 1967). Traditionally, rigid splinting for 2-3 months is recommended after displaced fragments havefirstbeen repositioned manually. The effect of repositioning on pulp survival and the type of healing has not been investigated.

Ideally, thefragmentsshould heal by union with hard tissue to form a single functioning tmit, with normal

Clinical follow-up

ComespcRidence: Mrs }. A. Yates, Department of Orthodontics and Dentistry far Children, United Medical and Dental Schools. Guy's Hospital, London SEl 9RT, UK.

The type of healing is usually determined by standardized clinical and radiographic examination. Hard tissue healing is indicated by normal vitality and mobility associated

150

Root fractures in permanent teeth

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I'ig. 1. Healing with hard tis.sue. (a) Middle-third fracture at 4 days. Tiie crown was moderately mobile but not displaced, (b) At 38 months the tooth is \>ital, there is continued root growth, no sclerosis, and the fracture line is barely visible.

'(b)

Fig. 2. Healing with fibrous tissue, (a) At 11 months an occlusal view shows separate coronal and apical fragments, with partial sclerosis apically and at the fracture line. There is rounding of the fracture margins, (b) At 3 2 months the tooth remains vital, and a periapical view shows an apparent ellipsoid fracture line with little further sclerosis.

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]. A. Yates

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Fig. 3. Healing with bone, (a) Middle-third fracture at 5 days. The crown was slightly mobile and extruded, ib) .At 3 5 months the tooth is vital, but the fragments are widely separated by bone following aiveolar growth. There is complete sclerosis of both fragments.

with a fading of the fracture line on the radiographs, although the fracture line almost always remains visible (Fig. 1 j . Connective tissue healing is indicated by normal vitality but slightly increased mobility. In the case of fibrous tissue healing, there is a persistent radiolucent line at the site of the fracture and, frequently, rounding of tbe margins (Fig. 2). If the fragments are widely separated, then bone forms between them. Ah'eolar growth may result in further separation of the fragments (Fig. 3). The presence of a non-vital pulp is associated with bone or root resorption at the fracture line (Andreasen et al. 1989). The tooth shows increased mobility, does not respond to vitality tests, and may also be discoloured. However, acute Infection or formation of a sinus tract is rare (Andreasen 1989). Diagnosis of loss of vitality is usually made within 2-5 months, on the basis of a combination of clinical and radiographic signs Qacobsen & Kerekes 1980, Andreasen 1989), A negative response to vitality tests alone is not considered to be conclusive. If the coronal pulp becomes non-vital, the coronal canal should be treated with calcium hydroxide to obtain a calcific barrier at the fracture line, then root-filled vi'ith gutta-percha and cement (Cvek 1974).

Aim of the study Uncertainty about the pulpal status of many rootfractured teeth led to the decision to review ail the cases of root fractures that had been treated in the department from 1976 and had adequate records. The aim of the study was to determine the criteria and the interval required for accurate diagnosis of pulpal status. Materials and methods A retrospective study of case records and radiographs was conducted on 21 patients with root fractures who attended the Royal Dental Hospital between 19 76 and its closure in 1985. Patients seen a short time after tbe injury had displaced teeth repositioned manually and their teeth were splinted if they were mobile. In earlier cases, a vacuum-moulded splint was cemented in place. In later cases, a passive wire held by composite resin to etcbed enamel was used. The splint was left in situ for a mean period of 11.7 weeks, and radiographs were used to assess the state of maturity of the teetb. The root apex was classified as being divergent, parallel-sided, convergent or closed. The teeth were observed clinically

Root fractures in permanent teeth Tabie 1. Additional iniuries observed in patients with root firactures

Table 2. Clinical complications observed in root-fractured teeth

Type of injury

Complication

> 1 root fracture Avulsion Crown fracture Teeth non-vital or sclerosed Alveolar fracture

Number of patients

2 1 1 8 0

for loss of vitality, presence of a sinus tract, increased mobility, tenderness to percussion, colour change and response to vitality tests (ethyl chloride and electric pulp tester). Bisecting angle periapical radiographs were used to detect pulp canal obliteration, resorption of tooth or bone (particularly at the fracture tine), and to determine the type of healing. These were the standard views used by the radiology department at that time. They are particularly useful for examination of root fractures because of the angulation of the fracture line in most teeth (Andreasen 1981). At each review, the other incisors were also checked clinically, and radiographs were taken if clinical findings were abnormal. Healing with hard tissue was indicated by the fracture line becoming fainter with no rounding of the margins. Healing with fibrous tissue was indicated by a persistent radioiucent line between the fragments with rounding of the margins. Healing with bone was indicated by the presence of bone between tbe fragments. Ail of tbese were associated with a positive response to vitality tests and absence of a sinus tract, tenderness to percussion and colour change. Healing with a non-vital coronal pulp was indicated by the presence of an acute abscess or sinus tract, a bony radiolucency at tbe fracture line, a change of colour, a change of response to vitality tests from positive to negative, or a persistent negative response for a period of more than 1 year. Teeth considered to be non-vital were filled with calcium hydroxide to the fracture line until a barrier formed, then root filled with gutta-percha and cement. Results Epidemiology Twenty-one patients were seen, of age range 9-20 years (mean age 12.0 years). Of these, 10 patients were less than 11 years old. 15 patients were male, and six were female, A total of 22 root-fractured teeth was discovered: 21 upper central incisors and one lower incisor. In 10 patients, more than one tooth was injured (Table 1), but

Excessive mobility noted by patient Acute infection Sinus tract Discoloration

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Number of teeth

0 0 0 4

in no case was there an associated alveolar fracture. Initial presentation was often delayed. Thus only six teetb were seen on the day of injury, and a fiirther five within the first week. The remaining 11 teeth were first seen up to 3 years after the injury. Clinical and radiographic findings Radiographs revealed that the fracture occurred in the middle third in 20 teeth and in tbe apical tbfrd in two teeth. Twenty teeth had closed or almost closed apices (convergent root canals), while only two were immature, with divergent root canals, and no tooth had a parallel-sided canal. There was enormous variation in the degree of root development with age. Analysis of the records revealed that in 10 teeth the coronal portion was displaced, but in only five was it repositioned. Twelve teeth were splinted (mean splinting time 11.7 weeks). Review The teeth were observed for a mean interval of 51.1 months, ranging from 6-92 months. Table 2 shows that during the follow-up no patient complained of excessive mobility, no tooth experienced an acute abscess, said none developed a sinus tract. Four teetb became discoloured, but in only one case was this within the first 2 months (Table 3). An apical radiolucency was not detected in any tooth, but in one case the apex underwent replacement resorption. Twenty teeth showed sclerosis of the apical root canal. Those that showed no sclerosis were one inrunature tooth and one observed for only 6 months. Sclerosis wasfirstdetected between 4 and 20 months, but almost all were seen by 13 months. Sclerosis progressed rapidly over a period of several months, but continued change could be observed over several years. Root canai treatment was perfonned on a total of five teeth. In the latter, a barrier was obtained at the fracture line following calcium hydroxide therapy, thus enabling a good root filling to be placed.

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TaUe 3. Changes in coioiir and response to totality tests Number of teeth (interval before change noted)

Test result Negative thionghout Negative to positive Positive throughout Positive to negative Discoloration

2' 2 (5 months, 8 months) 14 4 (6 weeks. 7 weeks, 6 months, 16 months) 4 (6 w e d s . 13 months. 14 months. < 18 months)

Includes one tooth with sclerosis of the cxironal pulp, indicating an intact biood supply.

coronal sclerosis when healing was by fibrous tissue or bone, and extensive coronal sclerosis only occurred in these teeth. The type of healing in relation to displacement, repositioning and splinting is shown in Table 6. Seven teeth healed with hard tissue, 10 teeth healed with fibrous tissue or bone, and 5 teeth became non-vital. Ten teeth were displaced, but only five were repositioned. Whereas seven out of twelve of the undisplaced teeth healed with hard tissue, none of the displaced teeth did so. There was no clear difference between teeth that were repositioned and those that were not repositioned. Twelve teeth were splinted, and slightly fewer teeth became non-vital compared to the unsplinted teeth. As might be exiiected, bone occurred between the fragments only when the coronal fragment was displaced.

Table 4. Radiogra^duc changes observed in root-fractured teeUi

Discussion Complication

Number of teeth

Resorption of bone at fracture line

1

Resorption of tooth at fracture line

0

Resorption of apical fragment (replacement)

1

Periapical radiolucency

0

Canai sclerosis apically

20

Canal sclerosis at fracture iine

11

Extensive canal sclerosis coronally

6

The root-fractured teeth were vitality tested over a prolonged period (Table 3). Four teeth gave an initial negative response. Of these, two changed to a positive response (after 5 months and 8 months, respectively). Eighteen teeth gave an initial positive response. Of these, four later became non-vital (afiter 6 weeks, 7 weeks, 6 months and 16 months, respectively). Table 4 shows that radiolucency at the fracture line was observed in only one offivenon-vital teeth, and root resorption at the fracture line was not detected in any of these teeth. The radiographs showed extensive coronal sclerosis in six teeth, including one tooth that failed to respond to vitality tests throughout. It must be assumed that the latter tooth had an intact blood supply. A further 11 teeth showed narrowing of the root canal near the fracture. Detailed analysis ofthe relationship between sclerosis and the type of healing is shown in Table 5. There was always some

Epidemiology Root fractures, although rare, are said to be frequently associated with fracture of the alveolar process, and to occur most commonly in the H -2 0 year age group, being unusual before 11 years of age (Andreasen 1981). However, Jacobsen and Zachrisson (1975) did not find that root fractures were associated with alveolar fractures. In this study of 21 patients with root fractures, there were no alveolar fractures, and 10 children were less than 11 years of age. Almost 50% of the patients (10) had injuries to more than one tooth, although these were not always detected at the time of injury. Many were discovered later, when teeth adjacent to the fractured tooth became non-vital or sclerosed (8 teeth). This emphasizes the importance of examining and reviewing all anterior teeth, even if they are not obviously injiu^ed. In this study, boys outnumbered gfrls by 15 to six, and 21 of the 22 root fractures were found in upper central incisors.

Repositioning and splinting Eleven teeth were first seen at the hospital more than 1 week after the accident. At this stage, repositioning was impossible and splinting not always necessary because the tooth wasfirmat that time, Thus, although in 10 teeth the coronal fragment was displaced, manual repositioning occurred in only five teeth because of late presentation. This would have decreased the chance of healing by hard tissue, although in this small sample there were no cases of healing by hard tissue in repositioned teeth. Similarly, otily 12 out of 22 teeth were splinted, although

Root fractures in permanent teeth Table 5. T^pe of sclerosis in relation to the type of healing

Type of healing Hard tissue

Fibrous tissue

Bone

Non-vital pulp

Total

0 5 2.

4 J 0

2 1 0

0 2 3

6 11 5

Hard tissue

Fibrous tissue

Bone

Non-vital pulp

Total

All teeth

7

7

3

5

22

Not displaced

7

3

0

2

12

Displaced

0

4

3

3

10

Displaced— repositioned

0

2

1

2

5

Displaced— not repositioned

0

2

2

1

5

Splinted

4

4

2

2

12

Not splinted

3

3

1

3

10

Type of sclerosis Extensive coronal scieioste FracUire line sclerosis No coronal sclerosis

early rigid splinting is stated to improve the prognosis (Andreasen & Hjorting-Hansen 1967). Splinting with orthodontic bands and an archwire has been shown to worsen the prognosis compared with the use of etchretained composite resin (Andreasen et ai. 1989). Orthodontic bands were not used in this study, but the earlier splints were made of vacuum-moulded acrylic, and cemented in place. The effect of these on the prognosis is not known. Criteria and timescakfor the diagnosis of healing with a non-vital pulp Determination of the type of healing was made on the basis of clinical and radiographic examination. Andreasen et aJ. (19 8 9) claimed that teeth can usually be recognized as non-vital within the first 2 months after injury. He suggested that teeth that did not respond to vitality tests at the time of injury were more likely to be diagnosed as non-vital at a later date, but that rescnption of bone at the fracture line was the main criterion for determining this. In the present study, reversal of vitality tests occurred at long intervals after the injury (Table 3).

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Tahle 6. The eOect of displacement and splinting on the type of healing

Of four teeth that gave a negative response initially, one continued to give a negative response throughout, but radiographs showed sclerosis of the coronal pulp, indicating an intact blood supply. Two other teeth subsequently gave a positive response (at 5 months sind 8 months, respectively). Thus only one tooth with an initially negative response subsequently had a necrotic pulp. This compares with four of the 14 teeth that initially responded to vitality tests but later became non-vital. It would appear that the initial response to vitality tests is not a good predictor of pulp survival in children. The interval before accurate diagnosis of the pulp condition is also significant, jacobsen and Zachrisson (1975) noted reversal of vitality tests from negative to positive over periods of up to 1 year after the original injury. Jacobsen and Kerekes (1980) reported reversal of vitality testsfrompositive to negative after 2-9 months. They also observed discoloration of the crown within 2 months. In this study, reversal of vitality tests from positive to negative was noted up to 16 months after the injury, and discoloration of the crown was observed up to 14 months Eifter the injury. Only one case of discoloration was observed within 2 months. Thus the interval required for

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]. A. Yates

accurate diagnosis of pulpal status would appear to be even longer than previously reported. Only one out offiveteeth judged to be non-vital showed resorption of bone at the fracture iine, and none showed root resorption at the fracture line. Andreasen et al. (1989) used resorption as the main criterion for assessment ofloss ofvitality. On that basis, only one tooth would have been recorded as non-vital in this study. Jacobsen and Kerekes (1980) observed resorption within 3-5 months in only nine out of 20 non-vital teeth. Their patients were of a similar age to those in this study, where only one out of five non-vital teeth showed resorption of bone. These results suggest that resorption of bone and root at the fracture line cannot be used as the main criterion for loss of vitality in this age group. Even using additional criteria such as response to vitality tests and change in colour, a definitive diagnosis may not be made within the first year.

Resorption and bacterial contamination It has been shown in monkeys that resorption of bone occurs only when the necrotic pulp becomes infected (Moller et al. 1981). Unlike coronal fractures involving the pulp, in root-fractured teeth there is no contamination of the pulp at the time of injury. The source of subsequent infection has not been established, but infection would not appear to be blood borne (Delivanis & Fan 1984). It could occur via the periodontal ligament, with bacteria reaching the pulp via the fracture line or through cervical dentine tubules. This could happen if there was a gap between cementum and enamel. Such gaps have been found in 10% of teeth (Berkovitz et al. 1977). Cervical cementum may also be damaged at the time of injury, exposing the dentinal tubules on the root surface. Cvek et al. (1990) have described such damage following forceps extraction of teeth, cind suggest that similar damage may occur in luxation injtuies when the bone margin acts as a fulcrum. Infection via the periodontal ligament might be expected to occur more readily in older patients with periodontal disease. In the present study, the patients were young and did not have periodontal breakdown. This could possibly account for the low levels of resorption observed.

The effect of displacement and splinting on the type of healing In this study none of the ten displaced teeth healed by hard tissue. This is not surprising, as half die teeth were not

repositioned due to late presentation. Even if repositioned, the incidence of hard tissue healing was lower in displaced teeth. Splinted teeth remained vital more often than unsplinted teeth (Table 6). The incidence of different types of healing is in agreement with previous reports (Andreasen & Hjerting-Hansen 1967, Andreasen et al. 1989). However, if all the teeth had been seen shortly alter the injury and splinted, the incidence of healing by hard tissue might well have been higher than the observed 32%, and the incidence of non-vital pulps lower than 23%.

Pulp canal sclerosis Sclerosis of tbe root canal was a common sequel to root fracture. It was usually detected by 13 months, and showed rapid progress initially, but increasing sclerosis could be detected over many years. Extensive sclerosis of the corona! puip only occurred when healing at the fracture site was by fibrous tissue or bone (Table 5). Sclerosis at the fracture line was seen in all vital teeth except two, which healed by hard tissue. Sclerosis in the apical canal occurred in almost every case, whether the coronal pulp regained vitality or not. This indicates that the apical pulp must have suffered damage at the time of fracture, probably due to pressure at the apical foramen. Only one tooth under long-term review did not show apical sclerosis, and this was immature. In no tooth was there any evidence of loss of vitality of the apical pulp. However, one tooth showed extensive replacement resorption of the apex. Pulpal necrosis secondary to pulp sclerosis is stated to occur in 1 % of cases (Andreasen et al. 1987). It was not observed in this small sample, although one immature tooth became non-vital after healing with hard tissue, and another tooth became non-vital after a second injury.

Conclusions The effect of displacement of the coronal fragment and splinting on the type of healing observed in this study is in agreement with fn-evious findings. However, the criteria and timescale suggested for determining pulpal necrosis would appear to be inappropriate, at least in children. Radiographic signs may not be present, and in the absence of obvious radiographic or clinical signs, observation for longer than 1 year may be necessary to determine loss of vitality. Sclerosis of the root canal can usually be observed by the end of the first year, but may progress for many years. In vie w of the slow changes that

Root fractures inpermanent teeth may occur, a minimum observation period of 2 years is recommended for teeth with no apparent complications. In addition, the high incidence of injury to more than one tooth renders it essential to observe adjacent teeth for loss of vitality or sclerosis, as well as observing the root-fractured tooth.

Acknowledgements I would like to thank the Photographic Department at Guy's Dental School for producing the illustrations. References ANDREASEN F.M. (1989) Pulpal healing after luxation injuries and root fracture in the permanent dentition. Endodontics and Dental

Traumatology, 5.111-131. ANDRKASEN F.M. & ANDRBASEN J.O. (1988) Resorption and mineralization processes following root fractures of permanent incisors. Endodontics and Dental Traumatoii^y, 4, 202-214. AMDREASEN F.M., YD Z., THOHKEN B.L. & ANDERSEN P.K. (1987) The

occurrence of pulp canal obliteration after luxation injuries in the permanent dentition. Endodontics and Dental Traumatology, J, 103-115. ANDREASEN F.M., ANDREASEN J.O. & BAYER T. (1989) Prognosis of rootfractured permanent incisors—prediction of healing modalities. Endodonlics and Dental Traumatoiogy. S, 11-22.

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ANDREAS™ J.O. (1981) Traumatic Injuries of the Teeth. 2nd edn. Munksgaaid. Copenhagen. A^4DREASHli J.O. & HieRTiNG-HANSEN E. (1967) Intra-alveolar root fractures: radiographic and histologic study of 50 cases. Journal of Oral Surgertf, 2 5 , 4 1 4 - 4 2 6 . BiRKOviTZ B.K.D., HOLLAND G.R. & MOXHAM B.J. (1977) A Colour Atlas and Textbook of Oral Anatomy, p. 107. Wolfe Medical Publications, London. CVEK M . (1974) Treatment of non-vital permanent incisors with calcium hydroxide. IV. Periodontal healing and closure of the root canal in the coronal fragment of teeth with intra-aiveolar fracture and vital apical fragment. A foQow-up. Odontologisk Revy, 2 5 , 239-246. CVEK M., CLEATON-JONES P.. AUSTIN J., KUNG M., LOWNIE J. & FATTT P.

(1990) tSect of topical application of doxycyctine on ptilp revascularization and periodontal healing in reimplanted monkey incisors. Endodontics and Dental Traumatology, 6,170-176. DEUVANIS P . D . & FAN V.S.C. (1984) The localisaUon of blood-borne bacteria in instrumented unfilled and overinstrumented canals. Journal of Endodontics, 10, 5 2 ! - 5 2 4 . JACOBSEN I. & ZACHBXSSON B.U. (1975) Repair characteristics of root fractures in permanent anterior teeth. Scandinavian Jourmd ofDtntal

Research Si, 35S-i(A. JACOBSEN I. & KEREKES K. (1980) Diagnosis and treatment of pulp necrosis in permanent teeth with root fractin-es. Scandinavian Journal of Dental Research. 88, 370-376. MOLLER A.J.R.. FABRICIUS L . DAHLEN G.. OHMAN A.E. & HEYDEN G. (1981)

Influence on periapical tissues of indigenous oral bacteria and necrotic pulp tissue in monkeys. Scandinavian Journal of Dental Research. 8 9 . 4 7 5 - ^ 8 4 .

Root fractures in permanent teeth: a clinical review.

A retrospective study of 22 root fractures in 21 patients was performed. Ten patients were less than 11 years of age, and boys were involved more ofte...
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