Resorption Heithrsays

8/2/2019 Resorption Heithrsays

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Endodonticsve cervical rsorption:

rey S, Heithersay, MDS (Adel). FDS, RCS (Edin), FRACDSObjective: An investigation was undertaken to assess potentiai predisposing factors to invasive cervicairesorpi/on. Method and materials: A group of 222 patients with a totai of 257 teeth displaying varying de-grees of invasive cervical rsorption were analyzed. Fotentiai predisposing factors, induding trauma, intra-coronal bleaching, surgery orthodontics, periodontal root scaling or pianing, bruxism. deiayed eruption,developmental defects, and restorations were assessed from the patients'history and orai examination.Results: Ot the potentiai predisposing factors identified, orthodontics was the most common sole factor,constituting 21.2% of patients and 24.1 % of teeth exam ined. O ther factors w ere present in an additionai5.0% of orthodonticaiiy treated patients (4.3% of teeth), and these consisted principatiy ot trauma and/orintracoronai bieaching. T rauma was the second most frequent soie factor (14.0% of patients and 15.1% otteeth). Trauma in combination with intracoronai bleaching, orthodontics, or delayed eruption constituted anadditionai 11.2% ot patients (10.6% ot teeth), intracoronai bieaching w as found to be the sole potentialpredisposing factor in 4.5% of patients and 3.3% ot teeth, and an additionai 10 4% ot patients and 9.7% ofteeth showed a combination of intracoronai bieaching with trauma and/or orthodontics. Surgery particu-larly invoiving the cementoenam el unction area, was a sole potential predisposing factor in 6.3% of pa-tients and 5.4% of teeth. Periodontai therapy induding deep root scaiing and pianing. showed a low inci-dence, as did other factors, such as bruxism and developm ental de fects. The presence of an intracoronairestoration was the oniy identifiabie factor in 15.3% of patients and 14.4% of teeth, while 15 .0% of patientsand 16.4% of teeth showed no identifiabie potentiai predisposing factors. Conclusion: These resuits indi-cated a strong association between invasive cervical rsorption and orthodontic treatment, trauma, and in-tracoronai bieaching. either alone or in combination. (Quintessence int 1999:30:83-95)Key words: externai rsorption, invasive cervical rsorption

Ciinicians should be alert to

South Australia, Australia.ustraiia 50 00, Australia. Fax: 61-8-8410-0709.

Ectopic calcifications can also be obset^ed in advancedlesions, both within the invading fibrous tissue anddeposited on the resorbed dentin surface. The clinicaland histopathologic features of this condition havebeen outlined in a previous publication.'The etiology of invasive cervical rsorption is un-known, but several potential predisposing factors havebeen suggested. Of these, intracoronai bleaching-reiated rsorption has heen the most widely docu-mented factor, following the initial report by Harring-ton and Natldn in 1979^ (for a review, see Heithersayet aP). Trauma has also been recognized as a potentialcause of "late external root rsorption," the clinicaldescription of invasive cervicai rsorption adopted byCvek in 1981.'' Other potential predisposing factorsthat have also been explored include orthodontics,orthognathic and other dentoalveolar surgery, andperiodontai treatment.^-^

The present investigation was undertaken to assessvarious potential predisposing factors in a relativelylarge group of patients presenting with varying degreesof invasive cervical rsorption.


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H e i t h e r s a y

Class 4Fig 1 Clinical classilicalion ol invasive cervical rsorption.

METHOD AND MATERIALSThe subject material consisted of 257 teeth displayinginvasive cervical rsorption in 222 patients who hadbeen referred to the specialist endodontic practice ofthe author. Patients underw ent a clinical and radiologieexamination, and photographic records were taken

where appropriate. Specific details of age, sexmedical and dental history were recorded. Commouth radiographie surveys were taken whenevertiple rsorptions were deemed a possibility.The potential predisposing factors were assfrom the patients' history and oral examination. of specific incidents or treatments were also reco


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Heithersay

60-6455-595G 5445-4940-4435-3930-3425-29 ^ K20-2415-19tO-14

0

' 1

5

a Female Male

10 15 0 25No. ol patients

5 10 15 20 25 30No. o patients

Invasive cervio al rsorption: Sex and age distribution al Fig 3 Invasive cervical rsorption: Tiie number o( patients ac-cording to age group and severity of rsorption.

severity of trauma. Details of tionsurgical rootcanal treatment or adjunctive treatment, eg, intra-coronal bleaching.Intracoronal bleaching. In patients with a historyof intracoronal bleaching, details of previousinjuries or treatment, and the number and timingof intracoronal bleaching treatments.Surgery. The type of surgerj' in the related area,eg, surgical removal of unerupted or partiallyerupted teeth, or transplantation.Orthodontic treatment. The ages at the commence-ment and completion of orthodontics, and theorthodontic method employed.Periodontal root scaling or planing. The severityof periodontal involvement and the duration oftreatment.and the degree of tooth wear.

incidences that may he considered to be related tothis condition.Intracoronal restorations. When no other poten-ial predisposing factor was identifiable, the pres-nce of coronal restoration was recorded.

1. Class 1. Denotes a small invasive resorptive lesionnear the cervical area with shallow penetration intodentin.2. Class 2. Denotes a well-defined invasive resorptivelesion that has penetrated close to the coronal pulpchamber but shows little or no extension into theradicular dentin.3. Class 3. Denotes a deeper invasion of dentin byresorbing tissue, not only involving the coronaldentin but also extending at least to the coronalthird of the root.4. Class 4. Denotes a large invasive resorptiveprocess that has extended beyond the coronalthird of the root canal.The data were subjected to frequency analysis,which was the only statistical method deemed applica-ble to this study.

RESULTSOf the 222 patients, 114 were females and 108 weremales. The sex and age distribution at the time of diag-nosis is shown in Fig 2. The ages varied from 11 to 75years; the mean age was 37 years. Figure 3 indicatesthe severity of invasive cervical rsorption, as definedin Fig 1. by age group. The total number of teeth fromthis patient sample was 257, and their distribution isoutlined in Table 1.

The analysis of potential predisposing factors forthe patients is sutnmarized in Fig 4.


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He i thersay

T A B L E 1 Distribution of teeth sho win g invasivecervical rsorptionTooth

Central incrsorLateral incisorCanineFirst premolarSecond premolarFirst molarSecond molarThird molar

Maxillary75233423

2072

Mandibular121313

4726133

T A B L E 2 Distribution of patiet its and teethassociated with trauma aione or in cotnbinationwith other factorsPolentialpredisposing factors

Trauma as a sole factorTrauma and bleachingTrauma and orlbodonticsTrauma, bleaching, andorthodonticsTrauma and delayed eruptionTotal

No, ofpatients (%)31 (14.0%)17 (7.7%)3 (1.4%)

4 (1.8%)1 (0,5%)

56 (25,2%)

N o,teeth 39(15,19 (73 (1

4 (11 (0

66 (25

TraumaIntracoronalbleacbing

SurgeryOrthodonticsPenodoniics

BruxismDelayed eruption

Developmental defectsInterproximal stripping

RestorationUnknown

Sole factorsD Additional factors

10 20 30 40 50 60 70No ol patients

Fig 4 Invasive cervical rsorption. Distribution of potential pre-disposing factors lor patients.

Trauma

The distribution of teeth and patients showing traumaand related factors is shown in Table 2, The teeth mostfrequently affected by a sole history of trauma wereth e (1 ) maxillary central incisors {7.8/ii), (2 ) mandibu-iar lateral incisors (2,3%), (3 ) mandibular central in-cisors fl,6"/o), and (4) maxillary canines (1,2%).Illustrative case report. A 45-year-old man pre-sented for a routine examination. His maxillary leftcentral incisor had been luxated palatally 21 years ear-lier, repositioned, and splinted. The tooth was asymp-tomatic but showed a pink discoloration near the gin-gival margin on the palatal aspect (Fig 5a), and thelabial surface showed a small, dark surface defect (Fig

5b). A radiograph (Fig 5c) show ed a large, irreguldiolucent area extending to the crown and root.rsorption was classified as class 3,Intracoronal bleaching

The distribution of patients and teeth showing coronal bleaching and related factors is showTabie 3, The teeth most frequently affected by ahistory of intracoronal bleaching were the (1 ) mlary central incisors (3,1%) and (2 ) maxillary lincisors (0,3%),Illustrative case report. The patient, a 42-yeaman, noticed an irregularity on the palatal aspehis maxillary left lateral incisor. Examination revan erosive defect containing soft tissue on the pasurface of the incisor (Fig 6a); the labial surfaceintact (Fig 6b). No symptoms were associated this lesion. The patient had received fixed orthodtreatment at 20 years of age, when he was a dstudent.When he was 23 years old, his lateral incisor

luxated palatally while playing soccer. It was retioned within 30 minutes and splinted, Nonsurroot canal treatment proved necessary. This waslowed by intracoronal bleaching with 30% hydrperoxide activated thcrniocatalytically by an ultrlet lamp applied intermittently for 5 minutes.This was followed by a "walking bleaeh," in whcofton pellet, saturated with 30% hydrogen perowas sealed into the pulp chamber with Cavit (Efor 6 days. The procedure was repeated, and 8 later the access cavity was restored. The toothreassessed 2 and 7 years later, at which times was no radiographie evidence of invasive eerrsorption or periapical pathosis (Fig 6c),


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Heilhersay

a Palatal view of the anterior teeth of a 45-year-olcl man21. Note the pink discoloration in tfie gingival thirdofFig 5b "The enamel of Ihe labial surface of the maxillary leftcentral incisor displays a defect resulting from the trauma thai hadoccurred 21 years earlier

Fig 5c (lefi) The radiograph of the maxillary left centrai incisorreveals a large radiolucency superimposed over the outline ol theroot canal

TABLE 3 Distribution of patients and teethassociated with intracoronal bleaching aloneor in combination with other factorsPotentialpredisposing faetcrs

Bleaching as a sole faetorBleaching and traumaBieaching and orthodcnticsBleaching, trauma, andorthodonticsTolal

No. ofpatients (%)10 (4.5%)17 (7.7%)2 (0.9%]4 (1.8%)33(14.9%.)

No. cfteeth(%)10 (3.9%)19 (7,4%)2 (0.8%)4 (1 6%)

35(13.6%)

the same procedureat the 7-year recall. The subsequent

had beenand replaced with another material within

12years after the secondhenoticed an

of an extensive resorptive process inwas shown

of a radiolucent area

tending 3 to 4 mm into radicular dentin and cementum(Fig 6d). In addition, a periapical radiolucency couldbe observed, indicative of a periapical inflammatory re-sponse probably resulting from microbial leakage of theroot canal filling via the resorptive defect. The lesionwas classified as a class 3 invasive cervical rsorption.Surgery

The distribution of patients and teeth showing surgeryand related factors is shown in Table 4. The type ofsurgery varied. The removal of adjacent partially orfully unerupted third molars or superntimerary teeth


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iHeithersay

Fig 6a Palatal view ot the anterior eetii of a 42-year-oid manwhose maxillary left incisor tooth had been luxated 19 years ear-lier, 2 years after reoeiving orlhodohtic treatmeht. Nonsurgicai rootcahal treatment and intraooronal bleaohing proved neoessary,and intraooronal bleaohing was repeated 7 years later Note theerosive defect at the me siogirgiva i surface, evident 12 years afterthe second intracoronai bieaching procedure.

Fig 6b The abiai surface o the maxiiiary left lateral ishows some discoloration near the gingival margin but is wise intact.

Fig 6c A radiograph taken 7 years aftertrauma, nonsurgical root canai treatment,and intracoronai bieaching shows no evi-dence of rsorption or periapicai pathosis.Fig 6d A radiograph of the ma^iiiary leftiaterai incisor taken 12 years after a sec ondinlracoronai b leaching procedure showsevidence of e>;tensive invasive cervical r-sorption extending into the radicuiar andccronai looth structure. A periapicai radiolu-cency, indicative of periapicai patfiosis. isaiso evident.


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Heithersay

7a Labial surface ot the maxillary lefi canine of a 28-year-oldto expose an unerupted canine at thee ot 14years. Protracted orthodontic treatment followed. Noteat the distogingival surface with an associated softF ig 7b The palatai surtace of the maxillary left canine is intactand shows no clinical signs of rsorption.

F ig 7c (left) The radiographie appearance at the maxiilary ieltcanine reveis an irregular ladioiucency extending to the radicuiarIhird of the tooth and to the ccronai tooth structure in a crescentaipatlern.

TABLE 4 Distribution of patients and teethassociated with surgery alone or in combinationwith other factorsPotentialpredisposing factors

Surgery as a soie factorSurgery and orthodonticsSurgery and periodontaitherapyTotai

No. ofpatients (%)13 (5,9%]

1 (0,5%)1 (0.5%)

t5 (6 .8%)

No. Otteeth (%|13(5.1%)

1 (0.4%)1 (0.4%)

15(5 8%)

in eight patients (eight teeth). Transplan-of canine teeth hadbeen carried out in three

and the surgical exposure of anin one patient {one

Illustrative case report. A 28-year-old woman pre-of the gingival tissues

played a resorptive defect near the distogingival mar-gin [Figs 7a and 7b), Her dental history indicated thatthe previously unerupted canine had been surgicallyexposed when she was 14 years old, prior to orthodon-tic treatment. Records indicated that orthodonticmovement of this tooth was difficult and protracted.The radiograph (Fig 7c) indicated a class 3 rsorptiondefect, with extensions both eoronally and apically forat least a third of its depth.


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Heitnersay

Fig 8a Labial view o( tiie anterior teeth of a 2e-year-old womanwho haa received li \ed orthodontic treatment 14 years eariier. Tiiemaxiilary right centrai incisor shows a pink disco oration near thegingivai margin.

Fig 8b The paiaiai surface of the maxiiiary righ\ centrai appears normai

Fig 8c (ieft) The radiograph of the maxillary right central reveals an irregular radioiucency overlying the rool canai ou

TABLE 5 Distribution of patients and teethassociated with orthodontics alone or incombination with other factorsPotentialpredisposing factors

Orthodontics as a sole factorOrthodontics and traumaOrthodontics and bleachingOrthodontics, trauma, andbieachingOrthodontics and surgeryOrthodontics and periodontaltherapyTotal

No. ofpatients (%)47(21.2%)3 (1.4%)2 (0.9%l4 (1.8%)1 (0.5%)1 (0.5%)

58 (26.2%]

No. oteeth (62(24.1

3 (1.2 (0.4 (1.1 (0-1 (0.

73 (28-

OrthodonticsThe distribution of patients and teeth showing ortho-dontics and related factors is shown inTahle 5.Theteeth tnost frequently affected by orthodontics were (Ijmaxillary canines (6.2%), (2) maxillary central incisors(4.3%), (3) mandibular molars (2.3'>/o), and (4) maxillaryand mandibular incisors (\.9%). In those patients with ahistory of orthodontics alone, multiple rsorptions wererecorded in six patients (2.7%). Of these patients, onehad seven teeth involved, two patients had four teeth

involved, and three patients had two teeth involvedIllustrative case report. A 28-year-old womansented with a pink discoloration of the crown oasymptotTiatic maxillary right central incisor (Figand 8b). The patient had received fixed apporthodontic therapy 14 years earlier, apparentleventful both during and after the 2-year treatmenriod. The radiograph revealed an irregular radcency extending from the cervical area into the c(Fig 8c). This lesion was classified as class 2 invcervical rsorption.


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Heithersay Periodontal therapy

Bruxismx patients (2,8%) w ith SL\ teeth (2,4%) showed a his-

Deiayed eruption

Illustrative case report. The mandibular right ca-

prem olar (Fig 9c), The lesions w ere classified asss 3 ,Developmental defects

Other factors

Illustrative case report. A 22-year-old woman'sy a general dental p ractitioner w ho performed in-

g 10b). The lesion w as classified as class 3,intracoronal restorations

In 33 patients (14,9%) with 36 teeth (16.4%), no

TABLE 6 Distribution ot patients and teethassociated with periodontal therapy alone or incom bitiation with other factorsPolentialptedisposing factors

Periodontal therapy as asole lactorPeriodontal therapy andorthodonticsPeriodontal therapy andsurgeryTotal

No, ofpatients (%)4(1.8%)1 (0 57c)1 (0,5%)6 (2,8%

No.olteeth (%)4(1,6%]1 (0,4%)1 (0.4%)6 (2,4%)

DISCUSSIONTo date, there do not appear to have been any previ-ous epidemiologic studies that specifically indicatethe proportion of a population group that may de-velop invasive cervical rsorption. The present sampleof patients referred to the author, a specialist en-dodontist with a special interest in the condifion, rep-resents approximately 0,02''.''o of the population ofAdelaide, a city of approximately 1,2 million people,Several statistical tests were considered for this study,including analysis of variance, but the nonrandom-ized nature of subjects indicated that the only validstatistical method applicable was that of frequencyanalysis.There was little overall difference between malesand females in the incidence of invasive cervical r-sorption, but there were some interesting age groupvariations. In the 35- to 39-year-old group, the major-ity were males, which contrasted with the 45- to 49-year-old group, where the se x distribution was re-versed. While an analysis of potential predisposingfactors for the two groups gave no indication for thepredominance of females in the 45- to 49-year-oldgroup, males in the 35-year-old group had a pre-dictably greater history of dental trauma than females,no doubt resulfing from a greater participafion in con-tact sports. Surprisingly, males in this group also had agreater history of orthodonfic treatment.For invasive cervical rsorption to be inifiated, tbenormally protective cementum-eementoid layer mustbe deficient or damaged,' This may have occurreddevelopmentally or can be caused by physical orchemical trauma. Chemical trauma may be involved inthe initiation of invasive cervical rsorption associatedwith intracoronal bleaching with hydrogen peroxide,Intracoronal bleach-related cervical rsorption hasreceived the attention of the dental profession sincethe first case reports in 1979,'


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Heithersay

Fig 9a Delayed eruption of the mandibular right canine in a 35-year-oid man because of arch crowding.

Fig 9b Tine radiogra ph cf the mandibularright canine reveals an extensive radiolu-cency extending principally into the crown.Fig 9c An irregular radiolucency indicativeof Invasive cervicai rsorption is also evi-dent in the adjacent mandibuiar premoiar.The pulp outiine is demarcated from the ra-diolucency by a radiopaque line.

The results of the present study show that ntra-eoronal bleaching was the sole potential predisposingfactor in 4,5% of patients (3.9''/o of teeth). When com-bined with other potential predisposing factors, 14.9%of the patients surveyed, or 13.6"/o of the teeth, showeda history, at some stage, of intracoro nal bleaching withhydrogen pe rox ide . The in t racorona l b leach ingmethod varied between a thenitocatalytic techniquewith hydrogen peroxide and the walking bleachingmethod using hydrogen peroxide alone or mixed withsodium perborate. A combination of the two methodshad also been used.

Two studies have assessed the incidence of icoronal bleaching-related rsorption. Friedman found an incidence of 6.8"/o in a sample of 58 ttreated by either a thermocatalytic or a walbleaching technique. None of the teeth had a hisof traum a, A more rece nt study of 202 patitreated with a comhination of thermocatalytic walking bleaching reported an incidence of 1.9All teeth with rsorption in this study had a histortratima.This was also the case in each of the seven case


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Heilhersay

Pdlatal view of the maxiliary right canine ol a 22-year-old

y con tains reddish-pink soft tissue.

A radiograpn of Ihe maxil iary r ight canine shows the radicular de ntin. Nole the retained outline ot the root canalounded by the irreguiar radiolucency.

1979.- These au thor s suggested that

% hydrogen peroxide was demonstrated by Rotstein1991* and found to be facilitated by the presence ofFurther information regarding the possible patho-

Invasive cervical rsorption has been identified as a

ing the possibiiity of ingrowth of potentially resorbingcells from the periodontal ligament. Maxillary centralincisors were those predominant recorded in thisstudy, and this observation is consistent with theirstrategic vulnerability to dental trauma. The presentstudy also showed that more than one factor may beinvolved in the same patient, and this was particularlysignificant when there had been a history of traumaand bleaching.Surgical procedures involving the sensitive cemen-toenamei junction were identified as potential predis-posing factors in 6.80/0 of patients (5.8% of teeth). Thisrepresents a comparatively low incidence, consideringthe frequency of such treatment procedures. The re-moval of unerupted third molars has the potential fordamage to the cementoenamel junction of the adja-cent second molar, while the exposure of uneruptedcanines for orthodontic purposes may cause similardamage, especially if a cervical wire ligature is usedrather than a bonded bracket. Similar damage to thecementoenamel junction also occurred in one patientwho had a history of interproximal stripping.There were three patients with a history of orthog-nathic surgery who displayed root rsorption withsimilarities to invasive cervical rsorption. However,these patients were excluded from this study, becausethe predominating type of rsorption was replacementrsorption resulting from loss of the periodontal liga-ment and progressive root replacem ent by bone .


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i H e i t he rs ay

The highest incidence of invasive cervical rsorp-tion was found in patients with a history of orthodon-tic treatment; the rsorption was detected as early as18 months after tbe removal of appliances or as late as33 years. There was no correlation between the orth-odontic technique employed and the development ofthis type of rsorption. Some degree of surface rsorp-tion can occur during orthodonric treatment,'^ This r-sorption is usually transitory and wili undergo repairafter the removal of orthodontie fores,'^ However, ifsurface rsorption of eementum exposes the underly-ing dentin, then a potential will exist for rsorption tobe initiated by mononuclear precursor cells from tbeperiodontal ligament, sbould tbey be stimulated byotber factors. For example, pressure caused by exces-sive orthodontic forces may result in localized tissuenecrosis adjacent to denuded eementum. The resultingtissue metabolites may stimulate mononuclear precur-sor cells to differentiate into specific clastic cells,which couid cause active rsorption.It is of interest to note that, of the teeth with a his-tory of ortbodontics, maxillary canines were the mostcommonly recorded in this study, occurring as multi-ples in two patients. Recause of their position, toothlengtb, and bone support, canines often are more resis-tant to ortbodontic movement tban other teeth in thedental arch. Furthermore, if class 2 elastics are used intreatment, they are attached to the maxillary caninesand the mandibular first molars. This may translateinto greater forces on one root surface, whieh couldpredispose the area to invasive cervical rsorption.Maxillary central incisors were tbe next most fre-quently affected teeth. This bigh incidence may be dueto tbe position of the maxillary central incisors at theapex of the dental areh, where they couid be subjectedto greater tooth movement tban other teetb in thedentition. Mandibular molars were tbe third most fre-quently affected teeth. These teeth are often used asanchor teeth, and the orthodontie treatment may sub-ject some root surfaces to localized and perhaps exces-sive pressure du ring treatment.

Multiple rsorptions were present in six patientswitb a history of ortbodontics, the number varyingfrom two to seven teeth per patient. This suggests aneed for a complete-mouth radiographie examinationfor any patient with a history of orthodontic treatmentwho develops invasive cervical rsorption.The apparent association between invasive cervicalrsorption and orthodontic treatment must be viewedwithin the context of the frequency of orthodontictreatment within tbe community. There has been a sig-nificant inerease in the use of orthodontic serviceswithin South A ustralia since 1973, when a study indi-cated tha t only 7% of patients to the age of 14 yearswere using specialist orthodontic services.'"^ However,

that study did not assess the extent of orthodtreatment provided by the State School Dental Seand general dental practitioners at tbat rime. A recent study of the use of orthodontic services by bort of adolescents enrolled in tbe South AustrSchool Dental Service program'^ show ed that, b15 years, 27,30/o of young patients had received ortho don tic treatm ent, and 15.3% had also treated by removable appliances.An association between invasive cervical rsorand ortho don tics has been reported previously,^endodontic implications of orthodontic treatment been studied in 87 patients, aged 20 to 25 years,had received ortbodontic treatment earlier in lives. The au thors recorded only one case of cervicsorption in an incisor, representing 1.5% of the groA control group of a similar age range showed nodence of cervical rsorption. It should be notedoniy anterior teeth were examined in tbat study. Idition, tbe lag time between ortbodontic treatmethe diagnosis of invasive cervical rsorption can and tbis sb ould be tak en into con side ration incomparative study. In the present study, the averagof detection of invasive cervical rsorption in pawith a history of orthodontic treatment was 31,5 yDespite the opinion that cmentai defects appepredispose teeth to this type of rsorption,' periotai therapy with deep scaling or root planing waidentified in this study as a major potential prediing factor, being recorded as a sole factor in onlypatients (1,8%) witb four teetb (1.6%), When bined with other factors, namely, surgery or orthotics, the incidence was still low (2,8% of patients;of teeth}, Tbis may be due to the fact that in chperiodontal disease there may be inhibition orstruction of the precursor resorbing cells in the odontai ligament in the area of denud ed eementurapid epithelial downgrowth may effectively prcontact of connective tissue eells with that surface

Of the six patients with invasive cervical rsorassociated with bruxism, it was perhaps significathe occupational stress of our profession thatwere dentists and one a medical practitionerThe presence of intracoronal restorations may little significance in anterior teeth, but in postteeth they can be associated with the developmedcntinai and cmentai cracks, especially if the restions are supplemented with pins. Such cracks extend into the periodontal ligament and, accordimay ailow invasion of resorbing tissue.Delayed eruption resulting from tooth impacobserved in four patients (1.8%) and five teeth (Ltends to leave a tooth crown partially surroundeattached gingival tissues. This may result in eondsimilar to those obtained experimentally when gin


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Heithersay

cal rsorp tion was observed in as-ion w ith a high prop ortion of root surfaces.While 14.9% of patients (16.4% of teeth) did not

In 28.90.0 of patients, there was more than onetial pre disp osin g factor (for exam ple, 7.5% of

The present analysis shows that the majority of

Detection of invasive cervical rsorption at an early

CONCLUSION

REFERENCES1. Heithersay GS. Clinical, radiologie, and histopathologic fea-tures of invasive cervical rsorption. Quintessence Int1999;30:27-37.2. Harrington GW, Natkin E. Esternal rsorption associatedwith the bieiitliing of pulpless teeth. | Endod 1979;5-344-348.3. Heithersay GS, Dahlstrom SW, Marin PD. Incidence ofinvasive tervical rsorption in bleached root-filled teeth.Aust Dent I 1994 ;39:82-87.4. Cvek M. Endodontic treatment of traumatiscd teeth. In;Andreasen )0 (ed). Ttaumatic Injuries of the Teeth, ed 2.Copenhagen: M unksgaard, 1981:362-363.5. Tronstad L. Root resorption-Etiologi', terminology and elin-icai manifestations. Endod Dent Traumatoi 1988;4:241-252.6. Trope M, Chivan N. Root rsorption. In: Cohen S, BurnsRC (eds). Pathways of the Pulp, ed 6. St Louis: Mosby,1994:493-503.7. Hammarstrom L, Lindskog S. Factors regulating and modi-fying dental root rsorption. Pri>c Finn Dent Soc 1992;88(suppll):115-123.8. Friedman S, Rotstein I, Libfield H, Stabliolz A, Heling TIncidence of external root rsorption and esthetic results in58 bleached pulpless teeth. Endod Dent Traumatoi 1988;4:23-26.9. Rotstein I. In-vitro determination and quantification of 30%hydrogen peroxide penetration through dentin and cemen-tum during bleaching. Oral Surg Oral Med Oral Fathol1991:72:602-506.10. Rotstein 1, Torek Y, Misgav R. Effect of cementum defectson radicular penetration of 30"'' H^O^during intracoronalbleaching. I Endod 1991;17:230-233.11. Dahlstrom SW, Bridges TE, Heithersay GS. Hydroxyl radi-cal activity in thermocatalytically bleached root filled teeth.Endod Dent Traumatoi 1997:13:119-125.12. Barber AF, Sims MR. Rapid maxillary expansion and exter-nal root rsorption in man: An SEM study. Am ) Orthod1981:79 630-652.13. Langford SR, Sims MR Root rsorption, repair, and peri-odontal attachment following rapid maxillary expansion inman. Am J Orthod 1982:81:108-11514. Bajada S. Ulilisation of Orthodontic Services in SouthAustralia |thcsis|. University of Adelaide, 1973.15. Allister JH, Spencer AJ, Brennan DS Provision of ortho-

dontic care to adolescents in South Australia: The type, theprovider, and the place of treatment. Aust Dent J 1996:41:405-410.15. Cwyk F, Saint-Perre F, Tronstad L. Endodontic implicationsof orthodontic tooth movement [abstract 1039]. J Dent Res1984:63.17. Bogle G, Claffey N, Egelberg |. Healing of horizontal cir-cumferential periodontal defects following regenerativesurgery in beagle dogs. J Clin Pcriodontol 1985:12:837-849.


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Resorption Heithrsays