- Email: [email protected]
Root surface caries: a critical literature review
______ J A D A _______ R E V I E W
A R T I C L E S
Little information is available on the prevalence and clinical appearance of root surface caries. The literature shows that root surface caries is thought to be similar to coronal caries, but that certain diet-bacterial interactions might predispose to root surface caries. A scan of the literature concerning the epidemiology, etiology, microbiology, periodontology, as well as reporting methods and restoration treatment of root surface caries shows current practices and suggests future research.
Root surface caries: a critical literature review U rsu la Seichter, P rof Dr
longer life expectancy in humans has given rise to concern regard in g the state of oral health in older adults. Few papers in the literature discuss specific oral health problems re lated to increasing age.1-4 R oot surface caries, a form of caries that seems to appear mostly in older patients, was de scribed as an inflammatory process in 1979 by Abbott.5 Black6 did not distinguish between root and coronal caries and be lieved that both were caused by poor oral hygiene. In reviewing contemporary litera ture, it appears that root caries is still thought to be similar to coronal caries, but that certain diet-bacterial interactions m ight predispose to root surface caries. In one of the few existing epidem io logic studies,7 the distribution of root car ies in the population is distinct, depend in g on age and am ount of exposure of the cementum in the mouth. Little informa tion is available on the prevalence and clinical appearance of root caries. It seems likely that additional prophylactic mea sures are necessary to prevent caries on
A
the root surface. These measures can be discovered only after the causes and the m icrobiological factors of root caries have been scientifically examined. More re search w ill be necessary in the next few years to arrive at the best result. A rela tionship to periodontal diseases seems apparent. Unfortunately, periodontologists do not seem to be overly concerned about this problem, especially when cemen tum is exposed as a result of periodontitis or surgical treatment.8 Of necessity, den tal restoration for root caries must be dif ferent from restorations for coronal caries, because of the nature of tooth tissue sur rounding the cavity. Textbooks on opera tive dentistry call attention to the fact that cementum is not as resistant to acid attack as enamel, and is therefore more prone to caries. However, the texts rarely offer a solution for the problems associated with placing restorations below the cementoenamel junction.9,10 T his paper presents a review of the literature on root surface caries, paying attention to the epidem iology and prob
lems of reporting methods, as w ell as to causes and associated m icrobiological fac tors. Additionally, the relation to periodontology, prevention, and types of den tal restoration is discussed. T he outlook on the need for further data on prevalence and incidence, as well as for in vitro and in vivo research is also presented. Epidemiologic studies Exam ination of ancient skulls shows that root caries was more frequent than coro nal caries in ancient humans. Data from New Guinea show that the prevalence of root caries in p rim itiv e societies is h ig h .11,12 At 30 to 39, this type of caries exceeds coronal caries but it also appears to some extent in younger age groups of the natives. A rapid progression of radic ular cavitation is reported combined with periodontal pocket formation. The sus ceptibility to both types of caries has been described by other authors in Western populations. Raetzke and others13 found no relationship between the prevalence of JADA, Vol. 115, August 1987 ■ 305
REVIEW
A R T I C L E S
coronal and root caries am ong patients with periodontal disease. A large number of epidem iologic publications describes radicular lesions as an age-related disease. T he pits and fissures of teeth in older people are filled with a dark, leathery' nonbiodegradable pellicle that decreases the occurrence of an active coronal le14 sion. Katz and others15 and Sumney and oth ers16 have identified more frequent root lesions in older people, particularly in m andibular molars. In contrast, Banting and others17 describe radicular caries main ly on the proxim al surfaces of anterior teeth of older adults living in long-term care facilities. Residents of hospitals are
root caries leads to some confusion and does not really help in better understand ing the problem. There are various rea sons for this: —Different and specific p opu lations have been examined (for exam ple, the military, people living in- and outside long-term care facilities, people w ho use illicit drugs, and isolated populations, such as rural or native communities). Representative population studies on root caries have not been published. —T he only common denominator in all the publications is the correlation with age and gingival recession. Statements on the influence of oral hygiene, gender, diet, or the distribution on teeth surfaces are
I he rate of edentulism in older adults has been decreasing; therefore, more teeth have been retained and are susceptible to root caries. considered to be a high-risk population as a result of their inability to perform good oral hygiene and because of dietary factors.18 However, a direct correlation between diet and the incidence of root caries has not been described in the ep i dem iologic surveys.15 18 T his is in con trast to the findings on the relationship between diet and coronal caries, which has been well documented.19,20 T he rate of edentulism in older adults has been decreasing. Therefore, more teeth are retained and are susceptible to root caries.21 Many of the lesions are untreated and are usually not noticed until a spe cific exam ination is done, particularly when the exam ination is done in isolated or rural com m unities.22 Individuals with root caries show higher scores for gin gi val inflamm ation, pocket depth, and re cession than those without.23,24 A signifi cant difference in oral hygiene cannot always be found in subjects with and without root surface caries.16 A Finnish survey26 identifies more root lesions in higher age groups and correlates them with gender. Lesions occurred more fre quently in men than in w om en.25,26 In a military population, the incidence of root caries was low (15.9%) in comparison with other studies.27 Poor oral hygiene condi tions, nutrition, and, particularly, avita m inosis, are described in an early publi c a tio n 28 as the reasons for a high inci dence of cervical caries among people who use illicit drugs. Analyzing the epidem iologic data on 306 ■ JADA, Vol. 115, August 1987
often contradictory. —The scoring methods differ greatly. These facts explain the difference between the reported prevalence values, w hich range from 15% to 83%. T he National Institute of Dental Research (NIDR) has developed methods for scoring root caries for epidem iologic investigations; however, these methods have not always been ap plied and no common index has been developed for use in surveys on coronal caries. This increases the difficulty of com paring the different epidem iologic data and enhances the danger of misinterpreta tion of results. Scoring methods Methods for reporting coronal caries in epidem iologic surveys have been described for many years and are broadly used by all examiners. A system for scoring dental caries in animals was published by Keyes in 1958.29,30 U ntil the early 1980s, there was no standardized method for scoring data on root caries in humans. Doff and others described31,32 a method for quanti tative scoring of root surface caries in rats. Doff modeled the am ount of exposed root surfaces after the Gupta and Shaw33 bone loss score. Katz developed an index for the prevalence of root caries in hu mans, together with a specific explorer for its detection.34 37 M ethodologies for the diagnosis of root caries are generally different from those for coronal caries.38
T he index from Katz is the only known and well-described root caries index and could help to close the gap in the stan dardization of epidem iologic data. Katz addresses the definition, measurement, and reporting measures of this specific disease, including visual-tactile, radiographic, and surface location criteria. T his index, if generally used, could increase the consen sus in the clinical description of radicular lesions. Causes and histopathologic factors A precondition for the development of root caries is gingival recession with sub sequent exposure of the root surface to the oral environm ent.11,12,39 In some coun tries the number of systematic periodon tal treatments is still low in spite of high prevalence of periodontal diseases.40 Periodontally involved cementum has been reported as being softer than uninvolved cem entum.41 Root surfaces are exposed in cases of advanced periodontitis, necessi tating periodontal surgery. Ravald and Ham p42 demonstrated that the develop ment of root caries in patients who had had periodontal treatment was strongly correlated to the patient’s previous root surface caries, low saliva secretion rates, high Lactobacillus counts, and advancing age. However, a correlation between oral hygiene and the incidence of cemental caries does not always exist.43 In animal models, cervical caries with involvement of the cementum normally occurs in older animals with gingival re cession or in younger anim als with severe periodontal disturbances.29 Stahl44 sug gests that the response of the root surface to periodontal inflamm ation is lysis of cementoblasts, changes in the precementum-cementum interface, decrease in sur face mineralization, and cemental resorp tion. These alterations do not necessarily appear in exposed surfaces. Areas of unal tered tissue may be found close to altered tissue.45 In demineralized areas, an intact surface zone is generally found under which the lesion spreads into the underly ing dentin.46,47 Areas w ith an intact sur face zone appear clinically noncarious. T he carious cementum has an uneven surface with tablet-shaped crystals.48 A densely mineralized layer is often found close to the cementodentinal junction.49 Examinations of the microhardness of the root surface show that its reduction is greater in the inner than in the outer den tin.50 Pocket formation apparently has a reducing effect on the microhardness of the dentin. Bacteria penetrate into the
RE V IE W
cementum at an earlier stage than into enamel, but the rate of bacterial invasion is relatively low, depending on environ mental factors like diet and the reduction of salivary flow. Schachtele and others51 discuss an ingestion of greater quantities of fermentable carbohydrates resulting in a decrease in sense of taste and sm ell with increasing age. H ix and O ’Leary52 found a higher incidence of root caries among older patients w ith periodontal disease who had a higher fermentable carbohy drate intake, but n o significant difference in plaque scores was noticed in patients with and without lesions. An in vitro model with an acidified gel system has been used to study initial phy sicochemical changes in root caries and the depth of penetration. It is often diffi cult to accurately estimate these changes in clinical exam inations.53,54 Banting and Courtright55 examined natural root sur face lesions on extracted teeth and found that most were less than 1 mm deep. C lin ically, it can be observed that the progres sion of root caries is often slow and the lesions are rather shallow. Microbiological factors Many investigators have shown that Strep tococcus mutans and Lactobacillus are involved in the cause of enamel lesions.56 58 In contrast, m inim al microbiological data exist on the bacterial initiation of root surface caries in humans. S mutans induces cemental caries and periodontal bone loss in anim als.59-62 S mutans is not always found in plaque samples from carious hum an root sur faces. When it is identified, its percentage of the total am ount of flora is generally h igh .63 Furthermore, S mutans with the characteristics of enterococci have been found. Most researchers do not compare m icrobiological data of plaque samples from carious and sound root surfaces. Ellen and others64 found low S mutans populations on initially cariesfree lesions and have suggested that there m ust be a significant difference between the bacte rial colonization of sound and carious tooth surfaces. Actinomyces viscosus was described as a dominant organism in plaque samples from carious lesions.62 T his is in close agreement with investigators who have demonstrated that A viscosus produces periodontal disease and root caries in anim als.65,66 T he idea that a unique form of bacterial flora exists that initiates car ies on different tooth surfaces has not yet been con vin cin gly proved by the pub
lished m icrobiological data regarding car ious root surfaces. T his finding may be the result of the different p opu lations examined and cultivating techniques used. However, there is no doubt that certain microorganisms are more often associated with root caries than others, such as strep tococci, actinomycetes, and enterococci. Certain diet-bacterial plaque infections that are not necessarily conducive to high ly active coronal caries seem to be related to periodontal disease and cemental car ies. Further investigation in this field w ould help to obtain a better knowledge on bacterial activity in the environment of exposed root surfaces and lead to the development of special preventive measure for this specific disease. Fluoride The best prevention against root caries would be the prevention of periodontal disease, w hich is strongly correlated to the buildup of plaque.67 T he discussion on the im portance of plaque, and thus oral hygiene, in the cause of root caries is still controversial. N o correlation between the hygiene status and the incidence of root caries was reported by H ix and O ’Leary,52 R avald and H am p ,42 and Raetzke.43 Lindhe and Nym an68 were able to show that repeated professional pro phylaxis can almost totally suppress the initiation of root caries. The age group involved in this specific disease is less able to carry out proper oral hygiene mea surements that w ould stress the im por tance of regular professional care.3 Apart
A R T I C L E S
strated by several investigators as the result o f the high absorption ability of cem en tum resulting from its perm eability.72 Even with low fluoride concentration in topical or systemic applications, high fluoride contents are found in cementum. T he fluoride content found in carious cementum is even higher than in sound cem entum , particularly in the surface layers.73,74 T veit75 found a high fluoride uptake by root surfaces that had been treated with a fluoride varnish. However, T veit con cludes that the concentration and the method of application of fluoride for pre venting root caries m ight not be the same as for preventing enamel caries. T he use of a metal fluoride solution as a protec tion against root caries seems favorable. A low pH results in a high appearance of fluoride, which easily penetrates into the tissue.76 Stamm and Banting77 have dem onstrated that life-long consum ption of fluoridated water significantly reduces the prevalence of root caries in humans. Fluoride is an effective substance for the reduction of root caries. As root caries is often found in the older population, it is stressed that fluoride is not only benefi cial for children but also for older adults. There is a need for further research con cerning the m ost optim al concentration and m ethod of application for preventing root caries. Treatment T he restoration of root caries lesions pro duces more difficulties than restoration of
7 he identification of dietary habits and eventual change and control of diet always have to be included in a complete preventive program.
from that, the age-related reduced salivary flow rate as an inductive factor for root caries cannot be easily controlled. Often it is the result of a life-m aintaining medica tion and, therefore, cannot be eliminated. The identification of dietary habits and eventual change and control of diet always have to be included in a complete preven tive program. Apart from plaque and diet control, fluoride application can be im portant in the prevention of root surface caries. Cementum concentrates fluoride to a much higher degree than any other cal cified tissue.69"71 This has been dem on
coronal lesions. Cementum and dentin are less resistant to acid attack and a re currence of caries at imperfect margins is m ore probable in cem en tu m than in enamel. T he acid-etch technique cannot be applied on root surfaces to improve the marginal adaptation. Etching enlarges the tubular openings and dissolves the mineralized tubular contents, which per mits a bacterial invasion.78 The location of root caries lesions makes moisture control, visibility, and access dif ficult.79 T he materials that can be used for restorations are amalgam, composite Seichter : R O O T SURFACE CARIES ■ 307
REV IE W
A R T I C L E S
resins, and glass ionomer cements. Amal gam is easy to m anipulate and its poten tial for corrosion at the tooth-amalgam interface helps to reduce microleakage. A m algam cannot be used in cases in which esthetic appearance is important. Glass ionom er cement has the advantage of adhering to dentin and slowly releas ing fluoride ions, which helps to prevent
Glass ionomer cement adheres to the dentin. This is a great advantage for res torations in the roots, especially where the acid-etch technique is contraindicated. During the setting action, a crosslinking between the material and the calcium ions of the dental tissue takes place.84 With glass ionomers, an extended cavity prepa ration is not necessary. Only the carious
Fluoride is an effective substance in regard to the reduction of root caries, but there is a need for further investigation on the optimal concentration and the best method of application.
the recurrence of caries.86 Composite res ins, particularly the microfilled compos ite resins, are superior to glass ionomer cements for esthethic appearance.87 Herrin and Shen80 favor amalgam as a restoration material. They examined the microleakage of different materials after application in vitro. Amalgam initially has a high rate of microleakage, which slows significantly with time because of the corrosion of the material. This closes the microgap. With amalgam, a high degree of postoperative sensitivity is clin ically observed as a result of the initial gap, but the long-term performance is superior to other materials. Amalgams containing zinc show poorer results when contaminated with moisture, which can not always be avoided in the treatment of root caries. Therefore, it is suggested that an amalgam without zinc should be used when moisture contam ination cannot be eliminated. T he disadvantage of amalgam is its clinical appearance. T he material with the best esthetic re sults is composite resin. There is normally a large selection of colors, but it is still not possible to obtain an excellent mar g in .81 T he surface of microfilled com pos ites can be polished, which reduces the possibility of plaque accumulation. The use of special bonding agents decreases the initial gap, but does not lead to accept able results.82 A slight closure of the initial gap has been observed with time, proba bly resulting from water absorption.83 Composite resins have no caries-prevent in g effects, like amalgam with its anticor rosion properties or glass ionomer cement with its fluoride content. Therefore, post operative sensitivity, discoloration, and recurrence of caries are often observed in root caries lesions restored with com pos ite resins. 308 ■ J A D A , Vol. 115, A u g u s t 1987
cementum and dentin have to be removed. The handling of the glass ionomer cement is difficult. It is sensitive to moisture and has a long setting time, during which the environment has to be kept dry.85 Iono mer fillings are usually lost shortly after placement because of mistakes in the man agement of the material. Clinical observa tions show failure rates of 9% to 2% after 6 months to 2 years.86 88 After 4 years, 75% of the fillings have been reported as being completely retained.89 Wesenberg and Hals90 have demonstra ted that glass ionom er cements have a surprisingly high solubility in an artifi cial caries system. The initial pH of the material is rather low (2.5), which indi cates a toxic effect in the initial state. After 24 hours, the pH rises to 5.3 and toxicity decreases.91 Cooper92 recommends a biocom patible lin in g material when the cavity floor is close to the pulp. This m ight decrease the bonding effect, but it protects the tooth. Apart from the fact that glass ionomer cements have a questionable esthetic ap pearance, they seem to be an appropriate material for the restoration of root caries lesions. Currently, no clinical long-term trials on restorations of root caries with glass ionomer cements have been reported. T he publications available discuss glass ionomer cement restorations of cervical abrasions and erosions.
not entirely remove infected dentin.94 Be cause carious dentin shows a higher flu o ride concentration than sound dentin, this may indicate that the progression of car ies w ill decrease or even stop after topical fluoride application, regardless of the re m aining infected areas. Summary Little information is available on the prevalence and clinical appearance of root surface caries. This paper reviews the liter ature and thereby analyzes the status of knowledge on root surface caries and the need for further investigation. Special emphasis is given to epidem iology, scor ing methods, etiology, histopathology, microbiology, fluoride, and treatment. There is still a lack of representative population studies on root surface caries. All the possible factors that m ight influ ence the development of this special type of caries have not yet been clearly de scribed. T he scoring methods of various in v estig a to rs differ rem arkably. It is known that gingival recession is one of the predominant causal factors in the occurrence of root caries. This indicates a strong relationship between periodontal disease and radicular lesions. Another in ducing factor m ight be diet, but certain, yet unknown, diet-bacterial plaque infec tions that are not necessarily conducive to highly active coronal caries seem to be related to periodontal disease and cemental caries. It is well documented that fluo ride is an effective substance in regard to the reduction of root caries, but there is a need for further investigation on the o p timal concentration and the best method of application. The treatment of radicular lesions is still a specific problem of re storative dentistry. T he marginal adapta tion cannot be improved by the use of the acid-etch technique for the obvious danger of pulp damage. Furthermore, the loca tion of root caries lesions make moisture control, visibility, and access difficult. Lately, the use of glass ionomer cements seems to offer a solution for the restora tion of these lesions.
-------------------- JIODA -------------------Conclusions N o known material is perfect for cervical restorations. Therefore, a recontouring and sm oothing, particularly of small and shallow lesions, and a topical application of fluoride is a good alternative to cavity preparation and restoration.93 In vitro studies indicate that this procedure does
Dr. Seichter is associate professor, K linik fur ZMK, A bteilu n g fu r Z a h n erhaltung, M artinistr 52, 2000 H a m b u rg 20, W est G erm any. A ddress requests for reprints to the author. 1. H azen, S.P.; C hilton, N.W .; and M um m a, R.D. T h e pro b lem of ro o t caries: literature review an d c lin ical description. JADA 86(1): 137-144, 1973. 2. Jo rd a n , H.V., an d Sum ney, D.L. R o o t surface caries: review of lite ra tu re a n d significance of the
REVIEW
problem . J Periodontol 44(3): 158-163, 1973. 3. B anting, D.W., a n d E llen, R .P . C arious lesions o n the roots of teeth: a review for th e gen eral p ra c ti tioner. J C an D ent Assoc 42(10):499-504, 1976. 4. H u n t, R .J.; Field, H .M .; an d Beck, J.D . T h e prevalence of perio d o n tal co n d itio n s in a n o n in s titu tionalized elderly p o p u latio n . G erodontics 1(4):176180, 1985. 5. A bbott, F. Caries o f h u m a n teeth. D ent C osm os 21:57, 113, 177, 1879. 6. Black, G.V. Black’s w ork o n operative d entistry w ith w h ic h h is special d ental p a th o lo g y is com bined, ed 7. T h e patholo g y o f th e h a rd tissues o f the teeth; o ral diagnosis, vol 1. C hicago, M edico-D ental P u b lish in g Co, 1936. 7. Bass, C.C. Previously undescribed dem onstrable p ath o lo g ic c onditio n in exposed cem entum a n d the u n d e rly in g dentine. O ral S urg 4(3):641-643, 1951. 8. Proye, M .P., an d P oison, A.M. Effect of ro o t s u r face alte ra tio n s o n p e rio d o n ta l h ealin g . S u rg ical de n u d a tio n . J C lin Perio d o n to l 9(6):428-440, 1982. 9. N ew brun, E. C ariology, ed 2. B altim ore, W il liam s & W ilkins, 1983. 10. G ottlieb, B. D ental caries; its etiology, p a th o l ogy, clin ic al aspects an d p ro p h y la x is. P h ilad e lp h ia , Lea & Febiger, 1947, p 190. 11. Scham schula, R .G ., a n d others. Prevalence an d in te rrelationship of ro o t surface caries in Lufa, P ap u a, New G uinea. C om m u n ity D ent O ral E pidem iol 2(6): 295-304, 1974. 12. S cham schula, R.G .; Keyes, P .H .; an d H o rn abrook, R.W . R o o t surface caries in L ufa, N ew G u in ea. C linical observations. JAD A 85(9):603-608, 1972. 13. Raetzke, P., an d others. D as A uftreten von Kar ies an freiliegenden W urzeloberflachen. G ib t es Zusam m enhänge m it der koro n alen K arieshaufigkeit? Dtsch Z ahnarztl Z 38(9):944-945, 1983. 14. M assier, M. G eriatrie dentistry: ro o t caries in the elderly. J Prosthet D ent 44(8):147-149, 1980. 15. Katz, R.V., a n d others. Prevalence a n d in trao ral d istrib u tio n of root caries in a n a d u lt p o p u la tio n . Caries Res 16(3):265-27I, 1982. 16. Sum ney, D.L.; Jo rd a n , H .V .; a n d E nglander, H .I. T h e prevalence of ro o t surface caries in selected po p u latio n s. J Periodontol 44(8):498-504,1973. 17. B anting, D.W.; E llen, R .P .; an d Fillery, E.D. Prevalence of root surface caries a m o n g in stitu tio n a l ized older persons. C o m m u n ity D ent O ral E pidem iol 8(2):84-88, 1980. 18. Seichter, U., an d K luppel, H .J. State o f oral h e alth a n d prevalence of ro o t caries in a n elderly p o p u la tio n . Caries Res 20(2):190, abstract no. 117, 1986. 19. H ardw ick, J.L . T h e incidence a n d d istrib u tio n of caries th ro u g h o u t the ages in relatio n to the E n g lish m a n ’s diet. Br D ent J 108(1):9-17, 1960. 20. G ustafsson, B., a n d others. T h e V ip eh o lm d en tal caries study. T h e effect o f different levels o f car b ohydrate in take o n caries activity in 436 individuals observed for five years. Acta O d o n to l Scand 11(1):232388, 1953. 21. US P u b lic H e alth Service. Decayed, m issing an d filled teeth a m o n g persons 1-74 years, U n ited States 1971-1974. Series 11, no. 223, D ep artm en t of H e alth a n d H u m a n Services p u b no. 81-1678, W ash in g to n , DC, G overnm ent P rin tin g Office, 1981. 22. Beck, J.D ., a n d others. Prevalence of ro o t a n d co ro n al caries in a n o n in stitu tio n a liz e d o ld er p o p u la tion. JAD A 111(12):964-967, 1985.23. B anting, D.W ., an d E llen, R .P . A lo n g itu d in a l study of d e ntal ro o t surface caries—p re lim in a ry re sults. J D ent Res (Special Issue) 57:150, abstract no. 304, 1978. 24. B anting, D.W.; Ellen, R .P .; a n d Fillery, E.D. A lo n g itu d in a l study of ro o t caries: baseline an d in c i dence data. J D ent Res 64(9):1141-1144, 1985. 25. V ehkalahti, M.; T ark k o n e n , L.; a n d P au n io ,
I.K. Risk of root caries. Caries Res 18(2):188, abstract no. 101, 1984. 26. Vehkalahti, M., and others. Prevalence of root caries in the adult Finnish population. Community Dent Oral Epidemiol 11(3):188-190, 1983. 27. Lohse, W.G.; Carter, H.G.; and Brunelle, J.A. T h e prevalence o f root surface caries in a military population. M ilit Med 142(9):700-703,1977. 28. Hecht, S.S., and Friedman, J. T h e high inci dence of cervical dental caries am ong drug addicts. Oral Surg 2:1428-1442, 1949. 29. Keyes, P.H . Dental caries in the m olar teeth of rats. D istribution of lesions induced by high-carbohydrate low-fat diets. J Dent Res 37(6):1077-1087,1958. 30. Keyes, P.H . Dental caries in the m olar teeth of rats. A method for diagnosing and scoring several types o f lesions simultaneously. J Dent Res 37(6): 10881099, 1958. 31. Doff, R.S.; Rosen, S.; and App, G. R oot surface caries in the molar teeth of rice rats. A m ethod for quantitative scoring. J Dent Res 50(8):1013-1016, 197732. Doff, R.S.; Rosen, S.; and App, G. R oot surface caries in the molar teeth of rice rats. Q uantitation of lesions induced by high sucrose diet. J Dent Res 56(9):1111-1114, 1977. 33. Gupta, O.P., and Shaw, J.H. Periodontal dis ease in the rice rat. Methods for evaluation of the extent o f periodontal disease. Oral Surg 9(l):727-735, 1956. 34. Katz, R.V. Development of an index for the prevalence of root caries. J Dent Res (Special Issue) 63(5):8I4-818, 1984. 35. Newitter, D.A.; Katz, R.V.; and Clive, J.M. De tection of root caries: sensitivity and specificity of a m odified explorer. Gerodontics l(2):65-67, 1985. 36. Katz, R.V. A method for scoring and reporting root caries in epidem iologic studies. AA D R Programs and Abstracts 58(1194):623,1979. 37. Katz, R.V. Assessing root caries in populations: the evolution of the root caries index. J Public Health Dent 40(1 ):7-10, 1986. 38. Katz, R.V. Root caries: clinical im plications of the current epidemiological data. J Northwestern Dent 60(6):306-310, 1981. 39. El-Hadary, M.E., and others. A study of inci dence and distribution of root surface caries and its relation to periodontal disease. Egypt D ent J 21(2):4352, 1975. 40. Herforth, A., and Rein, R. Erhebungen zur Entwicklung und Situation der systematischen Parodontalbehandlung im Bereich der Zahnarztekammer Nordrhein von 1975-81. Dtsch Zahnarztl Z 39(2):158162,1984. 41. Daly, C.G., and others. Cementum involved in periodontal disease: a review of its features and clin i cal management. J Dent 7(3):185-193, 1979. 42. Ravald, N ., and Hamp, S.E. Prediction of root surface caries in patients treated for advanced peri odontal disease. J Clin Periodontol 8(5):400-414, 1981. 43. Raetzke, P. Wurzeloberflachenkaries bei Patienten mit Parodontalerkrankungen. Dtsch Zahnarztl Z 40(7):775-777, 1985. 44. Stahl, S.S. T he nature of healthy and diseased root surfaces. J Periodontol 46(3):156-161, 1975. 45. Nyvad, B., and Fejerskov, O. R oot surface car ies: clinical, histopathological and microbiological features and clinical im plications. Int Dent J 32(4): 312-326, 1983. 46. Furseth, R., and Johansen, E. T h e mineral phase of sound and caries hum an dental cementum studied by electronmicroscopy. Acta O dontol Scand 28(3):305-322, 1970. 47. Westbrook, J.L., and others. R oot surface car ies: a clinical, histopathologic and microradiographic investigation. Caries Res 8(4):249-255, 1974. 48. Furseth, R. Further observations on the fine structure of orally exposed and carious hum an dental
ARTICLES
cementum. Arch Oral B iol 16(l):71-85,1971. 49. Furseth, R., and Johansen, E. A microradio graphic comparison of sound and carious hum an dental cementum. Arch Oral B iol 13(10):1197-1206, 1968. 50. Emslie, R.D., and Stack, M.V. T he microhard ness of roots of teeth w ith periodontal disease. Dent Pract 9( 12): 101-108, 1958. 51. Schachtele, C.F.; Rosam ond, W.D.; and Harlander, S.K. Diet and aging: current concerns related to oral health. Gerodontics 1(3):117-124, 1985. 52. H ix, J.O., and O ’Leary, T.J. T he relationship between cemental caries, oral hygiene status and fer mentable carbohydrate intake. J Periodontol 47(7):398404, 1976. 53. Phankosol, P., and others. H istopathology of the initial lesion of the root surface: an in vitro study. J Dent Res 64(5):804-809, 1985. 54. Phankosol, P., and others. Depth of penetra tion of in vitro root surface lesions. J Dent Res 64(6):897-899,1985. 55. Banting, D.W., and Courtright, P.N . D istribu tion and natural history of carious lesions on the roots of teeth. J Can Dent Assoc 41(l):45-49,1975. 56. D uchin, S., and Van Houte, J. R elationship of Streptococcus m u ta n s and lactobacilli to incipient sm ooth surface dental caries in man. Arch Oral Biol 23(9):779-786, 1978. 57. Loesche, W.J., and others. Association of Streptococcus m u ta n s w ith hum an dental decay. Infect Immun 11(6):1252-1260,1975. 58. Mikkelsen, L., and Poulson, S. M icrobiological studies on plaque in relation to developm ent of den tal caries in man. Caries Res 10(3):178-188, 1976. 59. Fitzgerald, R.J., and Keyes, P.H. Demonstra tion of the etiologic role o f streptococci in experimen tal caries in the hamster. JADA 61(1):9-19, 1960. 60. Guggenheim , B., and others. T he cariogenicity of different dietary carbohydrates tested in rats in rela tive gnotobiosis with a streptococcus producing extra cellular polysaccharide. Helv O dontol Acta 10(2):101113, 1966. 61. Krasse, B. H um an streptococci and experimen tal caries in hamsters. Arch Oral Biol ll(4):429-436, 1966. 62. Syed, S.A., and others. Predominant cultivable flora isolated from hum an root surface caries plaque. Infect Immun 11(4):727-731, 1975. 63. Sumney, D.L., and Jordan, H.V. Characteriza tion of bacteria isolated from hum an root surface car ies lesions. J Dent Res 53<2):343-351, 1974. 64. Ellen, R.P.; Fillery, E.D.; and Banting, D.W. Comparison of selective broth and plating methods for isolation of Streptococcus m u ta n s from root sur face dental plaque. J C lin M icrobiol ll(3):205-208, 1980. 65. Jordan, H.V.; Keyes, P.H.; and Bellack, S. Peri odontal lesions in hamsters and gnotobiotic rats infec ted w ith Actinomyces of hum an origin. J Periodontol Res 7(l):21-28, 1972. 66. Socransky, S.S.; Hubersack, C.; and Propas, D. Induction of periodontal destruction in gnotobiotic rats by a human oral strain of Actinomyces naeslundi. Arch Oral Biol 15(6):993-995,1970. 67. Loe, H.; Theilade, E.; and Jensen, S.B. Exper imental gingivitis in man. J Periodontol 36(3):177187,1965. 68. Lindhe, J., and Nym an, S. T he effect of plaque control and surgical pocket elim ination on the estab lishm ent maintenance of periodontal health. A lo n g i tudinal study of periodontal therapy in cases of ad vanced disease. J Clin Periodontol 2(2):67-69,1975. 69. Gedalia, I.; H illel, N.; and Scapira, J. Fluoride content of surface enamel, cem entum , lam ina dura and subperiosteal bone from mandibular angle of Hebrews. J Dent Res 44(2):452-457, 1965. 70. Singer, L., and Varmstrong, W.D. Comparison
Seichter : ROOT SURFACE CARIES ■ 309
REVIEW
ARTICLES
o f fluoride content o f hum an dental and skeletal tissues. J Dent Res 41(1):154-157,1962. 71. Brudevold, F.; Steadman, L.T.; and Sm ith, F.A. Inorganic and organic com ponents o f tooth structure. A nn NY Acad Sci 85(3):110-132, 1960. 72. Yardeni, J.; Gedalia, I.; and Kohn, M. Fluoride concentration o f dental calculus, surface enamel and cementum. Arch Oral Biol 8(6):697-701, 1963. 73. Stepnick, R.J.; Nakata, T.M.; and Zipkin, I. T he effects o f age and fluoride exposure on fluoride, citrate and carbonate content o f hum an cementum. J Periodontol 46(l):45-50,1975. 74. Furseth, R. A study of experimentally exposed and fluoride treated dental cem entum in pigs. Acta O dontol Scand 28(6):833-850,1970. 75. T veit, A.B. Fluoride uptake by enamel surfaces, root surfaces and cavity w alls follow ing application o f a fluoride varnish in vitro. Caries Res 14(5):315323, 1980. 76. T veit, A.B., and others. H igh ly acid SnF 2 and T iF 4 solutions—effect on and chemical reaction with root dentin in vitro. Caries Res 17(5):412-418, 1983. 77. Stamm, J.W ., and Banting, D.W. Comparison of root caries prevalence in adults w ith life-long resi dence in fluoridated and non-fluoridated com m uni ties. J Dent Res 59(A):552, abstract no. 552, 1980. 78. M ichelich, V.J.; Schuster, G.S.; and Pashley,
310 ■ JADA, Vol. 115, August 1987
D .H . Bacterial penetration of hum an dentin in vitro. J Dent Res 59(8):1398-1403,1980. 79. Schultz, L.C.; Charbeneau, G .T.; and Doerr, R.E. In Schultz, L.C., ed. Operative dentistry. Phila delphia, Lea 8c Febiger, 1966, p 86. 80. Herrin, H.K., and Shen, C. M icroleakage of root caries restorations. G erodontics 1(4):156-159, 1985. 81. Roulet, J.E.; Hirt, T.; and Lutz, F. Surface roughness and marginal behaviour of experimental and commercial composites: an in vitro study. J Oral Rehabil ll(5):499-509,1984. 82. H ansen, E.K. Effect of Scotchbond dependent on cavity cleaning, cavity diameter and cavosurface angle. Scand J Dent Res 92(2):141-147, 1984. 83. Bowler, R.L.; Rapson, J.E.; and Dickson, G. Hardening shrinkage and hygroscopic expansion of com posite resins. J Dent Res 61(5):654-658,1982. 84. Crisp, S., and W ilson, A.D. Reactions in glass ionom er cements. T he precipitation reaction. J Dent Res 53(6):1420-1424, 1974. 85. McLean, J.W., and W ilson, A.D. T h e clinical developm ent o f the glass-ionomer cements. Formula tions and properties. Aust Dent J 22(l):31-36, 1977. 86. Flynn, M. Clinical evaluation of Cervident and ASPA in restoring teeth w ith cervical abrasions. Oper Dent 4(3):118-120,1979.
87. Lawrence, L.G. Cervical glass ionom er restora tions: a clinical study. J Can Dent Assoc 45(2):58-59, 1979. 88. Low , T . T he treatment of hypersensitive cervi cal abrasion cavities using ASPA cement. J Oral Rehabil 8(l):81-89,1981. 89. Brandau, H.E.; Ziemiecki, T .L .; and Charbe neau, G.T. Restoration of clinical contours o n n on prepared teeth using glass ionom er cement: a 4H year report. JADA 108<5):782-783,1984. 90. Wesenberg, G.} and Hals, E. T he structure of experimental in vitro lesions around glass ionom er cem ent restorations in hum an teeth. J Oral Rehabil 7(2):175-184,1980. 91. Kent, B.E.; Lewis, B.G.; and W ilson, A.D. T he properties of a glass ionom er cement. Br D ent J 135(7):322-326, 1973. 92. Cooper, I.R. T h e response of the hum an dental pu lp to glass ionom er cements. Int Endod J 13(2):7688, 1980. 93. B illings, R.J.; Brown, L.R.; and Kaster, A.G. Contemporary treatment strategies for root surface dental caries. Gerodontics l(l):2 0 -2 7 ,1985. 94. B illings, R.J., and others. In vitro studies on treatment of incipient root caries. J Dent Res 61 (2):210, abstract no. 285,1982.
A R T I C L E S
Little information is available on the prevalence and clinical appearance of root surface caries. The literature shows that root surface caries is thought to be similar to coronal caries, but that certain diet-bacterial interactions might predispose to root surface caries. A scan of the literature concerning the epidemiology, etiology, microbiology, periodontology, as well as reporting methods and restoration treatment of root surface caries shows current practices and suggests future research.
Root surface caries: a critical literature review U rsu la Seichter, P rof Dr
longer life expectancy in humans has given rise to concern regard in g the state of oral health in older adults. Few papers in the literature discuss specific oral health problems re lated to increasing age.1-4 R oot surface caries, a form of caries that seems to appear mostly in older patients, was de scribed as an inflammatory process in 1979 by Abbott.5 Black6 did not distinguish between root and coronal caries and be lieved that both were caused by poor oral hygiene. In reviewing contemporary litera ture, it appears that root caries is still thought to be similar to coronal caries, but that certain diet-bacterial interactions m ight predispose to root surface caries. In one of the few existing epidem io logic studies,7 the distribution of root car ies in the population is distinct, depend in g on age and am ount of exposure of the cementum in the mouth. Little informa tion is available on the prevalence and clinical appearance of root caries. It seems likely that additional prophylactic mea sures are necessary to prevent caries on
A
the root surface. These measures can be discovered only after the causes and the m icrobiological factors of root caries have been scientifically examined. More re search w ill be necessary in the next few years to arrive at the best result. A rela tionship to periodontal diseases seems apparent. Unfortunately, periodontologists do not seem to be overly concerned about this problem, especially when cemen tum is exposed as a result of periodontitis or surgical treatment.8 Of necessity, den tal restoration for root caries must be dif ferent from restorations for coronal caries, because of the nature of tooth tissue sur rounding the cavity. Textbooks on opera tive dentistry call attention to the fact that cementum is not as resistant to acid attack as enamel, and is therefore more prone to caries. However, the texts rarely offer a solution for the problems associated with placing restorations below the cementoenamel junction.9,10 T his paper presents a review of the literature on root surface caries, paying attention to the epidem iology and prob
lems of reporting methods, as w ell as to causes and associated m icrobiological fac tors. Additionally, the relation to periodontology, prevention, and types of den tal restoration is discussed. T he outlook on the need for further data on prevalence and incidence, as well as for in vitro and in vivo research is also presented. Epidemiologic studies Exam ination of ancient skulls shows that root caries was more frequent than coro nal caries in ancient humans. Data from New Guinea show that the prevalence of root caries in p rim itiv e societies is h ig h .11,12 At 30 to 39, this type of caries exceeds coronal caries but it also appears to some extent in younger age groups of the natives. A rapid progression of radic ular cavitation is reported combined with periodontal pocket formation. The sus ceptibility to both types of caries has been described by other authors in Western populations. Raetzke and others13 found no relationship between the prevalence of JADA, Vol. 115, August 1987 ■ 305
REVIEW
A R T I C L E S
coronal and root caries am ong patients with periodontal disease. A large number of epidem iologic publications describes radicular lesions as an age-related disease. T he pits and fissures of teeth in older people are filled with a dark, leathery' nonbiodegradable pellicle that decreases the occurrence of an active coronal le14 sion. Katz and others15 and Sumney and oth ers16 have identified more frequent root lesions in older people, particularly in m andibular molars. In contrast, Banting and others17 describe radicular caries main ly on the proxim al surfaces of anterior teeth of older adults living in long-term care facilities. Residents of hospitals are
root caries leads to some confusion and does not really help in better understand ing the problem. There are various rea sons for this: —Different and specific p opu lations have been examined (for exam ple, the military, people living in- and outside long-term care facilities, people w ho use illicit drugs, and isolated populations, such as rural or native communities). Representative population studies on root caries have not been published. —T he only common denominator in all the publications is the correlation with age and gingival recession. Statements on the influence of oral hygiene, gender, diet, or the distribution on teeth surfaces are
I he rate of edentulism in older adults has been decreasing; therefore, more teeth have been retained and are susceptible to root caries. considered to be a high-risk population as a result of their inability to perform good oral hygiene and because of dietary factors.18 However, a direct correlation between diet and the incidence of root caries has not been described in the ep i dem iologic surveys.15 18 T his is in con trast to the findings on the relationship between diet and coronal caries, which has been well documented.19,20 T he rate of edentulism in older adults has been decreasing. Therefore, more teeth are retained and are susceptible to root caries.21 Many of the lesions are untreated and are usually not noticed until a spe cific exam ination is done, particularly when the exam ination is done in isolated or rural com m unities.22 Individuals with root caries show higher scores for gin gi val inflamm ation, pocket depth, and re cession than those without.23,24 A signifi cant difference in oral hygiene cannot always be found in subjects with and without root surface caries.16 A Finnish survey26 identifies more root lesions in higher age groups and correlates them with gender. Lesions occurred more fre quently in men than in w om en.25,26 In a military population, the incidence of root caries was low (15.9%) in comparison with other studies.27 Poor oral hygiene condi tions, nutrition, and, particularly, avita m inosis, are described in an early publi c a tio n 28 as the reasons for a high inci dence of cervical caries among people who use illicit drugs. Analyzing the epidem iologic data on 306 ■ JADA, Vol. 115, August 1987
often contradictory. —The scoring methods differ greatly. These facts explain the difference between the reported prevalence values, w hich range from 15% to 83%. T he National Institute of Dental Research (NIDR) has developed methods for scoring root caries for epidem iologic investigations; however, these methods have not always been ap plied and no common index has been developed for use in surveys on coronal caries. This increases the difficulty of com paring the different epidem iologic data and enhances the danger of misinterpreta tion of results. Scoring methods Methods for reporting coronal caries in epidem iologic surveys have been described for many years and are broadly used by all examiners. A system for scoring dental caries in animals was published by Keyes in 1958.29,30 U ntil the early 1980s, there was no standardized method for scoring data on root caries in humans. Doff and others described31,32 a method for quanti tative scoring of root surface caries in rats. Doff modeled the am ount of exposed root surfaces after the Gupta and Shaw33 bone loss score. Katz developed an index for the prevalence of root caries in hu mans, together with a specific explorer for its detection.34 37 M ethodologies for the diagnosis of root caries are generally different from those for coronal caries.38
T he index from Katz is the only known and well-described root caries index and could help to close the gap in the stan dardization of epidem iologic data. Katz addresses the definition, measurement, and reporting measures of this specific disease, including visual-tactile, radiographic, and surface location criteria. T his index, if generally used, could increase the consen sus in the clinical description of radicular lesions. Causes and histopathologic factors A precondition for the development of root caries is gingival recession with sub sequent exposure of the root surface to the oral environm ent.11,12,39 In some coun tries the number of systematic periodon tal treatments is still low in spite of high prevalence of periodontal diseases.40 Periodontally involved cementum has been reported as being softer than uninvolved cem entum.41 Root surfaces are exposed in cases of advanced periodontitis, necessi tating periodontal surgery. Ravald and Ham p42 demonstrated that the develop ment of root caries in patients who had had periodontal treatment was strongly correlated to the patient’s previous root surface caries, low saliva secretion rates, high Lactobacillus counts, and advancing age. However, a correlation between oral hygiene and the incidence of cemental caries does not always exist.43 In animal models, cervical caries with involvement of the cementum normally occurs in older animals with gingival re cession or in younger anim als with severe periodontal disturbances.29 Stahl44 sug gests that the response of the root surface to periodontal inflamm ation is lysis of cementoblasts, changes in the precementum-cementum interface, decrease in sur face mineralization, and cemental resorp tion. These alterations do not necessarily appear in exposed surfaces. Areas of unal tered tissue may be found close to altered tissue.45 In demineralized areas, an intact surface zone is generally found under which the lesion spreads into the underly ing dentin.46,47 Areas w ith an intact sur face zone appear clinically noncarious. T he carious cementum has an uneven surface with tablet-shaped crystals.48 A densely mineralized layer is often found close to the cementodentinal junction.49 Examinations of the microhardness of the root surface show that its reduction is greater in the inner than in the outer den tin.50 Pocket formation apparently has a reducing effect on the microhardness of the dentin. Bacteria penetrate into the
RE V IE W
cementum at an earlier stage than into enamel, but the rate of bacterial invasion is relatively low, depending on environ mental factors like diet and the reduction of salivary flow. Schachtele and others51 discuss an ingestion of greater quantities of fermentable carbohydrates resulting in a decrease in sense of taste and sm ell with increasing age. H ix and O ’Leary52 found a higher incidence of root caries among older patients w ith periodontal disease who had a higher fermentable carbohy drate intake, but n o significant difference in plaque scores was noticed in patients with and without lesions. An in vitro model with an acidified gel system has been used to study initial phy sicochemical changes in root caries and the depth of penetration. It is often diffi cult to accurately estimate these changes in clinical exam inations.53,54 Banting and Courtright55 examined natural root sur face lesions on extracted teeth and found that most were less than 1 mm deep. C lin ically, it can be observed that the progres sion of root caries is often slow and the lesions are rather shallow. Microbiological factors Many investigators have shown that Strep tococcus mutans and Lactobacillus are involved in the cause of enamel lesions.56 58 In contrast, m inim al microbiological data exist on the bacterial initiation of root surface caries in humans. S mutans induces cemental caries and periodontal bone loss in anim als.59-62 S mutans is not always found in plaque samples from carious hum an root sur faces. When it is identified, its percentage of the total am ount of flora is generally h igh .63 Furthermore, S mutans with the characteristics of enterococci have been found. Most researchers do not compare m icrobiological data of plaque samples from carious and sound root surfaces. Ellen and others64 found low S mutans populations on initially cariesfree lesions and have suggested that there m ust be a significant difference between the bacte rial colonization of sound and carious tooth surfaces. Actinomyces viscosus was described as a dominant organism in plaque samples from carious lesions.62 T his is in close agreement with investigators who have demonstrated that A viscosus produces periodontal disease and root caries in anim als.65,66 T he idea that a unique form of bacterial flora exists that initiates car ies on different tooth surfaces has not yet been con vin cin gly proved by the pub
lished m icrobiological data regarding car ious root surfaces. T his finding may be the result of the different p opu lations examined and cultivating techniques used. However, there is no doubt that certain microorganisms are more often associated with root caries than others, such as strep tococci, actinomycetes, and enterococci. Certain diet-bacterial plaque infections that are not necessarily conducive to high ly active coronal caries seem to be related to periodontal disease and cemental car ies. Further investigation in this field w ould help to obtain a better knowledge on bacterial activity in the environment of exposed root surfaces and lead to the development of special preventive measure for this specific disease. Fluoride The best prevention against root caries would be the prevention of periodontal disease, w hich is strongly correlated to the buildup of plaque.67 T he discussion on the im portance of plaque, and thus oral hygiene, in the cause of root caries is still controversial. N o correlation between the hygiene status and the incidence of root caries was reported by H ix and O ’Leary,52 R avald and H am p ,42 and Raetzke.43 Lindhe and Nym an68 were able to show that repeated professional pro phylaxis can almost totally suppress the initiation of root caries. The age group involved in this specific disease is less able to carry out proper oral hygiene mea surements that w ould stress the im por tance of regular professional care.3 Apart
A R T I C L E S
strated by several investigators as the result o f the high absorption ability of cem en tum resulting from its perm eability.72 Even with low fluoride concentration in topical or systemic applications, high fluoride contents are found in cementum. T he fluoride content found in carious cementum is even higher than in sound cem entum , particularly in the surface layers.73,74 T veit75 found a high fluoride uptake by root surfaces that had been treated with a fluoride varnish. However, T veit con cludes that the concentration and the method of application of fluoride for pre venting root caries m ight not be the same as for preventing enamel caries. T he use of a metal fluoride solution as a protec tion against root caries seems favorable. A low pH results in a high appearance of fluoride, which easily penetrates into the tissue.76 Stamm and Banting77 have dem onstrated that life-long consum ption of fluoridated water significantly reduces the prevalence of root caries in humans. Fluoride is an effective substance for the reduction of root caries. As root caries is often found in the older population, it is stressed that fluoride is not only benefi cial for children but also for older adults. There is a need for further research con cerning the m ost optim al concentration and m ethod of application for preventing root caries. Treatment T he restoration of root caries lesions pro duces more difficulties than restoration of
7 he identification of dietary habits and eventual change and control of diet always have to be included in a complete preventive program.
from that, the age-related reduced salivary flow rate as an inductive factor for root caries cannot be easily controlled. Often it is the result of a life-m aintaining medica tion and, therefore, cannot be eliminated. The identification of dietary habits and eventual change and control of diet always have to be included in a complete preven tive program. Apart from plaque and diet control, fluoride application can be im portant in the prevention of root surface caries. Cementum concentrates fluoride to a much higher degree than any other cal cified tissue.69"71 This has been dem on
coronal lesions. Cementum and dentin are less resistant to acid attack and a re currence of caries at imperfect margins is m ore probable in cem en tu m than in enamel. T he acid-etch technique cannot be applied on root surfaces to improve the marginal adaptation. Etching enlarges the tubular openings and dissolves the mineralized tubular contents, which per mits a bacterial invasion.78 The location of root caries lesions makes moisture control, visibility, and access dif ficult.79 T he materials that can be used for restorations are amalgam, composite Seichter : R O O T SURFACE CARIES ■ 307
REV IE W
A R T I C L E S
resins, and glass ionomer cements. Amal gam is easy to m anipulate and its poten tial for corrosion at the tooth-amalgam interface helps to reduce microleakage. A m algam cannot be used in cases in which esthetic appearance is important. Glass ionom er cement has the advantage of adhering to dentin and slowly releas ing fluoride ions, which helps to prevent
Glass ionomer cement adheres to the dentin. This is a great advantage for res torations in the roots, especially where the acid-etch technique is contraindicated. During the setting action, a crosslinking between the material and the calcium ions of the dental tissue takes place.84 With glass ionomers, an extended cavity prepa ration is not necessary. Only the carious
Fluoride is an effective substance in regard to the reduction of root caries, but there is a need for further investigation on the optimal concentration and the best method of application.
the recurrence of caries.86 Composite res ins, particularly the microfilled compos ite resins, are superior to glass ionomer cements for esthethic appearance.87 Herrin and Shen80 favor amalgam as a restoration material. They examined the microleakage of different materials after application in vitro. Amalgam initially has a high rate of microleakage, which slows significantly with time because of the corrosion of the material. This closes the microgap. With amalgam, a high degree of postoperative sensitivity is clin ically observed as a result of the initial gap, but the long-term performance is superior to other materials. Amalgams containing zinc show poorer results when contaminated with moisture, which can not always be avoided in the treatment of root caries. Therefore, it is suggested that an amalgam without zinc should be used when moisture contam ination cannot be eliminated. T he disadvantage of amalgam is its clinical appearance. T he material with the best esthetic re sults is composite resin. There is normally a large selection of colors, but it is still not possible to obtain an excellent mar g in .81 T he surface of microfilled com pos ites can be polished, which reduces the possibility of plaque accumulation. The use of special bonding agents decreases the initial gap, but does not lead to accept able results.82 A slight closure of the initial gap has been observed with time, proba bly resulting from water absorption.83 Composite resins have no caries-prevent in g effects, like amalgam with its anticor rosion properties or glass ionomer cement with its fluoride content. Therefore, post operative sensitivity, discoloration, and recurrence of caries are often observed in root caries lesions restored with com pos ite resins. 308 ■ J A D A , Vol. 115, A u g u s t 1987
cementum and dentin have to be removed. The handling of the glass ionomer cement is difficult. It is sensitive to moisture and has a long setting time, during which the environment has to be kept dry.85 Iono mer fillings are usually lost shortly after placement because of mistakes in the man agement of the material. Clinical observa tions show failure rates of 9% to 2% after 6 months to 2 years.86 88 After 4 years, 75% of the fillings have been reported as being completely retained.89 Wesenberg and Hals90 have demonstra ted that glass ionom er cements have a surprisingly high solubility in an artifi cial caries system. The initial pH of the material is rather low (2.5), which indi cates a toxic effect in the initial state. After 24 hours, the pH rises to 5.3 and toxicity decreases.91 Cooper92 recommends a biocom patible lin in g material when the cavity floor is close to the pulp. This m ight decrease the bonding effect, but it protects the tooth. Apart from the fact that glass ionomer cements have a questionable esthetic ap pearance, they seem to be an appropriate material for the restoration of root caries lesions. Currently, no clinical long-term trials on restorations of root caries with glass ionomer cements have been reported. T he publications available discuss glass ionomer cement restorations of cervical abrasions and erosions.
not entirely remove infected dentin.94 Be cause carious dentin shows a higher flu o ride concentration than sound dentin, this may indicate that the progression of car ies w ill decrease or even stop after topical fluoride application, regardless of the re m aining infected areas. Summary Little information is available on the prevalence and clinical appearance of root surface caries. This paper reviews the liter ature and thereby analyzes the status of knowledge on root surface caries and the need for further investigation. Special emphasis is given to epidem iology, scor ing methods, etiology, histopathology, microbiology, fluoride, and treatment. There is still a lack of representative population studies on root surface caries. All the possible factors that m ight influ ence the development of this special type of caries have not yet been clearly de scribed. T he scoring methods of various in v estig a to rs differ rem arkably. It is known that gingival recession is one of the predominant causal factors in the occurrence of root caries. This indicates a strong relationship between periodontal disease and radicular lesions. Another in ducing factor m ight be diet, but certain, yet unknown, diet-bacterial plaque infec tions that are not necessarily conducive to highly active coronal caries seem to be related to periodontal disease and cemental caries. It is well documented that fluo ride is an effective substance in regard to the reduction of root caries, but there is a need for further investigation on the o p timal concentration and the best method of application. The treatment of radicular lesions is still a specific problem of re storative dentistry. T he marginal adapta tion cannot be improved by the use of the acid-etch technique for the obvious danger of pulp damage. Furthermore, the loca tion of root caries lesions make moisture control, visibility, and access difficult. Lately, the use of glass ionomer cements seems to offer a solution for the restora tion of these lesions.
-------------------- JIODA -------------------Conclusions N o known material is perfect for cervical restorations. Therefore, a recontouring and sm oothing, particularly of small and shallow lesions, and a topical application of fluoride is a good alternative to cavity preparation and restoration.93 In vitro studies indicate that this procedure does
Dr. Seichter is associate professor, K linik fur ZMK, A bteilu n g fu r Z a h n erhaltung, M artinistr 52, 2000 H a m b u rg 20, W est G erm any. A ddress requests for reprints to the author. 1. H azen, S.P.; C hilton, N.W .; and M um m a, R.D. T h e pro b lem of ro o t caries: literature review an d c lin ical description. JADA 86(1): 137-144, 1973. 2. Jo rd a n , H.V., an d Sum ney, D.L. R o o t surface caries: review of lite ra tu re a n d significance of the
REVIEW
problem . J Periodontol 44(3): 158-163, 1973. 3. B anting, D.W., a n d E llen, R .P . C arious lesions o n the roots of teeth: a review for th e gen eral p ra c ti tioner. J C an D ent Assoc 42(10):499-504, 1976. 4. H u n t, R .J.; Field, H .M .; an d Beck, J.D . T h e prevalence of perio d o n tal co n d itio n s in a n o n in s titu tionalized elderly p o p u latio n . G erodontics 1(4):176180, 1985. 5. A bbott, F. Caries o f h u m a n teeth. D ent C osm os 21:57, 113, 177, 1879. 6. Black, G.V. Black’s w ork o n operative d entistry w ith w h ic h h is special d ental p a th o lo g y is com bined, ed 7. T h e patholo g y o f th e h a rd tissues o f the teeth; o ral diagnosis, vol 1. C hicago, M edico-D ental P u b lish in g Co, 1936. 7. Bass, C.C. Previously undescribed dem onstrable p ath o lo g ic c onditio n in exposed cem entum a n d the u n d e rly in g dentine. O ral S urg 4(3):641-643, 1951. 8. Proye, M .P., an d P oison, A.M. Effect of ro o t s u r face alte ra tio n s o n p e rio d o n ta l h ealin g . S u rg ical de n u d a tio n . J C lin Perio d o n to l 9(6):428-440, 1982. 9. N ew brun, E. C ariology, ed 2. B altim ore, W il liam s & W ilkins, 1983. 10. G ottlieb, B. D ental caries; its etiology, p a th o l ogy, clin ic al aspects an d p ro p h y la x is. P h ilad e lp h ia , Lea & Febiger, 1947, p 190. 11. Scham schula, R .G ., a n d others. Prevalence an d in te rrelationship of ro o t surface caries in Lufa, P ap u a, New G uinea. C om m u n ity D ent O ral E pidem iol 2(6): 295-304, 1974. 12. S cham schula, R.G .; Keyes, P .H .; an d H o rn abrook, R.W . R o o t surface caries in L ufa, N ew G u in ea. C linical observations. JAD A 85(9):603-608, 1972. 13. Raetzke, P., an d others. D as A uftreten von Kar ies an freiliegenden W urzeloberflachen. G ib t es Zusam m enhänge m it der koro n alen K arieshaufigkeit? Dtsch Z ahnarztl Z 38(9):944-945, 1983. 14. M assier, M. G eriatrie dentistry: ro o t caries in the elderly. J Prosthet D ent 44(8):147-149, 1980. 15. Katz, R.V., a n d others. Prevalence a n d in trao ral d istrib u tio n of root caries in a n a d u lt p o p u la tio n . Caries Res 16(3):265-27I, 1982. 16. Sum ney, D.L.; Jo rd a n , H .V .; a n d E nglander, H .I. T h e prevalence of ro o t surface caries in selected po p u latio n s. J Periodontol 44(8):498-504,1973. 17. B anting, D.W.; E llen, R .P .; an d Fillery, E.D. Prevalence of root surface caries a m o n g in stitu tio n a l ized older persons. C o m m u n ity D ent O ral E pidem iol 8(2):84-88, 1980. 18. Seichter, U., an d K luppel, H .J. State o f oral h e alth a n d prevalence of ro o t caries in a n elderly p o p u la tio n . Caries Res 20(2):190, abstract no. 117, 1986. 19. H ardw ick, J.L . T h e incidence a n d d istrib u tio n of caries th ro u g h o u t the ages in relatio n to the E n g lish m a n ’s diet. Br D ent J 108(1):9-17, 1960. 20. G ustafsson, B., a n d others. T h e V ip eh o lm d en tal caries study. T h e effect o f different levels o f car b ohydrate in take o n caries activity in 436 individuals observed for five years. Acta O d o n to l Scand 11(1):232388, 1953. 21. US P u b lic H e alth Service. Decayed, m issing an d filled teeth a m o n g persons 1-74 years, U n ited States 1971-1974. Series 11, no. 223, D ep artm en t of H e alth a n d H u m a n Services p u b no. 81-1678, W ash in g to n , DC, G overnm ent P rin tin g Office, 1981. 22. Beck, J.D ., a n d others. Prevalence of ro o t a n d co ro n al caries in a n o n in stitu tio n a liz e d o ld er p o p u la tion. JAD A 111(12):964-967, 1985.23. B anting, D.W ., an d E llen, R .P . A lo n g itu d in a l study of d e ntal ro o t surface caries—p re lim in a ry re sults. J D ent Res (Special Issue) 57:150, abstract no. 304, 1978. 24. B anting, D.W.; Ellen, R .P .; a n d Fillery, E.D. A lo n g itu d in a l study of ro o t caries: baseline an d in c i dence data. J D ent Res 64(9):1141-1144, 1985. 25. V ehkalahti, M.; T ark k o n e n , L.; a n d P au n io ,
I.K. Risk of root caries. Caries Res 18(2):188, abstract no. 101, 1984. 26. Vehkalahti, M., and others. Prevalence of root caries in the adult Finnish population. Community Dent Oral Epidemiol 11(3):188-190, 1983. 27. Lohse, W.G.; Carter, H.G.; and Brunelle, J.A. T h e prevalence o f root surface caries in a military population. M ilit Med 142(9):700-703,1977. 28. Hecht, S.S., and Friedman, J. T h e high inci dence of cervical dental caries am ong drug addicts. Oral Surg 2:1428-1442, 1949. 29. Keyes, P.H . Dental caries in the m olar teeth of rats. D istribution of lesions induced by high-carbohydrate low-fat diets. J Dent Res 37(6):1077-1087,1958. 30. Keyes, P.H . Dental caries in the m olar teeth of rats. A method for diagnosing and scoring several types o f lesions simultaneously. J Dent Res 37(6): 10881099, 1958. 31. Doff, R.S.; Rosen, S.; and App, G. R oot surface caries in the molar teeth of rice rats. A m ethod for quantitative scoring. J Dent Res 50(8):1013-1016, 197732. Doff, R.S.; Rosen, S.; and App, G. R oot surface caries in the molar teeth of rice rats. Q uantitation of lesions induced by high sucrose diet. J Dent Res 56(9):1111-1114, 1977. 33. Gupta, O.P., and Shaw, J.H. Periodontal dis ease in the rice rat. Methods for evaluation of the extent o f periodontal disease. Oral Surg 9(l):727-735, 1956. 34. Katz, R.V. Development of an index for the prevalence of root caries. J Dent Res (Special Issue) 63(5):8I4-818, 1984. 35. Newitter, D.A.; Katz, R.V.; and Clive, J.M. De tection of root caries: sensitivity and specificity of a m odified explorer. Gerodontics l(2):65-67, 1985. 36. Katz, R.V. A method for scoring and reporting root caries in epidem iologic studies. AA D R Programs and Abstracts 58(1194):623,1979. 37. Katz, R.V. Assessing root caries in populations: the evolution of the root caries index. J Public Health Dent 40(1 ):7-10, 1986. 38. Katz, R.V. Root caries: clinical im plications of the current epidemiological data. J Northwestern Dent 60(6):306-310, 1981. 39. El-Hadary, M.E., and others. A study of inci dence and distribution of root surface caries and its relation to periodontal disease. Egypt D ent J 21(2):4352, 1975. 40. Herforth, A., and Rein, R. Erhebungen zur Entwicklung und Situation der systematischen Parodontalbehandlung im Bereich der Zahnarztekammer Nordrhein von 1975-81. Dtsch Zahnarztl Z 39(2):158162,1984. 41. Daly, C.G., and others. Cementum involved in periodontal disease: a review of its features and clin i cal management. J Dent 7(3):185-193, 1979. 42. Ravald, N ., and Hamp, S.E. Prediction of root surface caries in patients treated for advanced peri odontal disease. J Clin Periodontol 8(5):400-414, 1981. 43. Raetzke, P. Wurzeloberflachenkaries bei Patienten mit Parodontalerkrankungen. Dtsch Zahnarztl Z 40(7):775-777, 1985. 44. Stahl, S.S. T he nature of healthy and diseased root surfaces. J Periodontol 46(3):156-161, 1975. 45. Nyvad, B., and Fejerskov, O. R oot surface car ies: clinical, histopathological and microbiological features and clinical im plications. Int Dent J 32(4): 312-326, 1983. 46. Furseth, R., and Johansen, E. T h e mineral phase of sound and caries hum an dental cementum studied by electronmicroscopy. Acta O dontol Scand 28(3):305-322, 1970. 47. Westbrook, J.L., and others. R oot surface car ies: a clinical, histopathologic and microradiographic investigation. Caries Res 8(4):249-255, 1974. 48. Furseth, R. Further observations on the fine structure of orally exposed and carious hum an dental
ARTICLES
cementum. Arch Oral B iol 16(l):71-85,1971. 49. Furseth, R., and Johansen, E. A microradio graphic comparison of sound and carious hum an dental cementum. Arch Oral B iol 13(10):1197-1206, 1968. 50. Emslie, R.D., and Stack, M.V. T he microhard ness of roots of teeth w ith periodontal disease. Dent Pract 9( 12): 101-108, 1958. 51. Schachtele, C.F.; Rosam ond, W.D.; and Harlander, S.K. Diet and aging: current concerns related to oral health. Gerodontics 1(3):117-124, 1985. 52. H ix, J.O., and O ’Leary, T.J. T he relationship between cemental caries, oral hygiene status and fer mentable carbohydrate intake. J Periodontol 47(7):398404, 1976. 53. Phankosol, P., and others. H istopathology of the initial lesion of the root surface: an in vitro study. J Dent Res 64(5):804-809, 1985. 54. Phankosol, P., and others. Depth of penetra tion of in vitro root surface lesions. J Dent Res 64(6):897-899,1985. 55. Banting, D.W., and Courtright, P.N . D istribu tion and natural history of carious lesions on the roots of teeth. J Can Dent Assoc 41(l):45-49,1975. 56. D uchin, S., and Van Houte, J. R elationship of Streptococcus m u ta n s and lactobacilli to incipient sm ooth surface dental caries in man. Arch Oral Biol 23(9):779-786, 1978. 57. Loesche, W.J., and others. Association of Streptococcus m u ta n s w ith hum an dental decay. Infect Immun 11(6):1252-1260,1975. 58. Mikkelsen, L., and Poulson, S. M icrobiological studies on plaque in relation to developm ent of den tal caries in man. Caries Res 10(3):178-188, 1976. 59. Fitzgerald, R.J., and Keyes, P.H. Demonstra tion of the etiologic role o f streptococci in experimen tal caries in the hamster. JADA 61(1):9-19, 1960. 60. Guggenheim , B., and others. T he cariogenicity of different dietary carbohydrates tested in rats in rela tive gnotobiosis with a streptococcus producing extra cellular polysaccharide. Helv O dontol Acta 10(2):101113, 1966. 61. Krasse, B. H um an streptococci and experimen tal caries in hamsters. Arch Oral Biol ll(4):429-436, 1966. 62. Syed, S.A., and others. Predominant cultivable flora isolated from hum an root surface caries plaque. Infect Immun 11(4):727-731, 1975. 63. Sumney, D.L., and Jordan, H.V. Characteriza tion of bacteria isolated from hum an root surface car ies lesions. J Dent Res 53<2):343-351, 1974. 64. Ellen, R.P.; Fillery, E.D.; and Banting, D.W. Comparison of selective broth and plating methods for isolation of Streptococcus m u ta n s from root sur face dental plaque. J C lin M icrobiol ll(3):205-208, 1980. 65. Jordan, H.V.; Keyes, P.H.; and Bellack, S. Peri odontal lesions in hamsters and gnotobiotic rats infec ted w ith Actinomyces of hum an origin. J Periodontol Res 7(l):21-28, 1972. 66. Socransky, S.S.; Hubersack, C.; and Propas, D. Induction of periodontal destruction in gnotobiotic rats by a human oral strain of Actinomyces naeslundi. Arch Oral Biol 15(6):993-995,1970. 67. Loe, H.; Theilade, E.; and Jensen, S.B. Exper imental gingivitis in man. J Periodontol 36(3):177187,1965. 68. Lindhe, J., and Nym an, S. T he effect of plaque control and surgical pocket elim ination on the estab lishm ent maintenance of periodontal health. A lo n g i tudinal study of periodontal therapy in cases of ad vanced disease. J Clin Periodontol 2(2):67-69,1975. 69. Gedalia, I.; H illel, N.; and Scapira, J. Fluoride content of surface enamel, cem entum , lam ina dura and subperiosteal bone from mandibular angle of Hebrews. J Dent Res 44(2):452-457, 1965. 70. Singer, L., and Varmstrong, W.D. Comparison
Seichter : ROOT SURFACE CARIES ■ 309
REVIEW
ARTICLES
o f fluoride content o f hum an dental and skeletal tissues. J Dent Res 41(1):154-157,1962. 71. Brudevold, F.; Steadman, L.T.; and Sm ith, F.A. Inorganic and organic com ponents o f tooth structure. A nn NY Acad Sci 85(3):110-132, 1960. 72. Yardeni, J.; Gedalia, I.; and Kohn, M. Fluoride concentration o f dental calculus, surface enamel and cementum. Arch Oral Biol 8(6):697-701, 1963. 73. Stepnick, R.J.; Nakata, T.M.; and Zipkin, I. T he effects o f age and fluoride exposure on fluoride, citrate and carbonate content o f hum an cementum. J Periodontol 46(l):45-50,1975. 74. Furseth, R. A study of experimentally exposed and fluoride treated dental cem entum in pigs. Acta O dontol Scand 28(6):833-850,1970. 75. T veit, A.B. Fluoride uptake by enamel surfaces, root surfaces and cavity w alls follow ing application o f a fluoride varnish in vitro. Caries Res 14(5):315323, 1980. 76. T veit, A.B., and others. H igh ly acid SnF 2 and T iF 4 solutions—effect on and chemical reaction with root dentin in vitro. Caries Res 17(5):412-418, 1983. 77. Stamm, J.W ., and Banting, D.W. Comparison of root caries prevalence in adults w ith life-long resi dence in fluoridated and non-fluoridated com m uni ties. J Dent Res 59(A):552, abstract no. 552, 1980. 78. M ichelich, V.J.; Schuster, G.S.; and Pashley,
310 ■ JADA, Vol. 115, August 1987
D .H . Bacterial penetration of hum an dentin in vitro. J Dent Res 59(8):1398-1403,1980. 79. Schultz, L.C.; Charbeneau, G .T.; and Doerr, R.E. In Schultz, L.C., ed. Operative dentistry. Phila delphia, Lea 8c Febiger, 1966, p 86. 80. Herrin, H.K., and Shen, C. M icroleakage of root caries restorations. G erodontics 1(4):156-159, 1985. 81. Roulet, J.E.; Hirt, T.; and Lutz, F. Surface roughness and marginal behaviour of experimental and commercial composites: an in vitro study. J Oral Rehabil ll(5):499-509,1984. 82. H ansen, E.K. Effect of Scotchbond dependent on cavity cleaning, cavity diameter and cavosurface angle. Scand J Dent Res 92(2):141-147, 1984. 83. Bowler, R.L.; Rapson, J.E.; and Dickson, G. Hardening shrinkage and hygroscopic expansion of com posite resins. J Dent Res 61(5):654-658,1982. 84. Crisp, S., and W ilson, A.D. Reactions in glass ionom er cements. T he precipitation reaction. J Dent Res 53(6):1420-1424, 1974. 85. McLean, J.W., and W ilson, A.D. T h e clinical developm ent o f the glass-ionomer cements. Formula tions and properties. Aust Dent J 22(l):31-36, 1977. 86. Flynn, M. Clinical evaluation of Cervident and ASPA in restoring teeth w ith cervical abrasions. Oper Dent 4(3):118-120,1979.
87. Lawrence, L.G. Cervical glass ionom er restora tions: a clinical study. J Can Dent Assoc 45(2):58-59, 1979. 88. Low , T . T he treatment of hypersensitive cervi cal abrasion cavities using ASPA cement. J Oral Rehabil 8(l):81-89,1981. 89. Brandau, H.E.; Ziemiecki, T .L .; and Charbe neau, G.T. Restoration of clinical contours o n n on prepared teeth using glass ionom er cement: a 4H year report. JADA 108<5):782-783,1984. 90. Wesenberg, G.} and Hals, E. T he structure of experimental in vitro lesions around glass ionom er cem ent restorations in hum an teeth. J Oral Rehabil 7(2):175-184,1980. 91. Kent, B.E.; Lewis, B.G.; and W ilson, A.D. T he properties of a glass ionom er cement. Br D ent J 135(7):322-326, 1973. 92. Cooper, I.R. T h e response of the hum an dental pu lp to glass ionom er cements. Int Endod J 13(2):7688, 1980. 93. B illings, R.J.; Brown, L.R.; and Kaster, A.G. Contemporary treatment strategies for root surface dental caries. Gerodontics l(l):2 0 -2 7 ,1985. 94. B illings, R.J., and others. In vitro studies on treatment of incipient root caries. J Dent Res 61 (2):210, abstract no. 285,1982.