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A Clinical Approach to the Treatment and Management of Rampant Root Caries

Gwen Cohen, Reinaldo J. Negron, Martin Bockler, DDS


Root caries is a common problem among the elderly. It afflicts a large percentage of geriatric patients and is a very difficult problem for dentists to manage. The etiology of root caries is multifactorial. The factors implicated in the development of root lesions include dietary habits, microbial plaque, and a decreased salivary flow. Root lesions are often very difficult to restore due to their location, problems with moisture control, and proximity to the pulp and are therefore prone to high recurrence rates. The treatment and management considerations for root caries vary depending upon the extent and location of the lesion, as well as the type of materials being used. The literature on this topic is quite abundant and one consistent theme found throughout root caries literature is that it must be treated quickly and efficiently, for root caries progresses much more rapidly in comparison to coronal caries.


INTRODUCTION


The mature adult patient today has a highly restored, compromised, dentition that requires maintenance."27 It is for this reason that many dentists spend a good portion of their time with the elderly patient re-restoring existing restorations that have been defeated by recurrent decay.27 Although root caries affects younger age groups as well, the disease has become more prevalent in the geriatric population due to the increased retention of natural teeth. Papas, Joshi, and Giunta, in a study of 326 middle-aged older adults, found that the mean DFS (decayed,filled,surfaces) per tooth for root caries consistently increased with increasing age.31 Root caries research studies have found that about one-third of the population up to sixty years of age experiences root caries. The prevalence of root caries in patients over sixty years of age ranges from 30% to 63%, depending upon the type of individuals studied and where the study took place. 1,15,25,31 The factors involved in root caries can be seen in Table 1.12,13,20,27,31,33,40

Table 1. Factors involved in root caries initiation
gender male
age retain teeth, saliva thicker and decreased flow
high sugar intake dietary habits
poor oral hygiene low dental IQ, physical disabilities


xerostomia 		Radiation, Sjogren's,
medications (diuretics, antipsychotics, antidepressants, sedative/hypnotics, antihistamines, antihypertensives)
microbial flora/plaque
periodontal disease
low fluoride exposure
smoking
pre-existing restorations highly restored teeth


Many factors are in essence indirectly linked with root caries and directly linked with each other, but nonetheless are significant contributory factors. Root caries can be found alone, or, often, approximating existing restorations. However, root caries may only occur where there has been recession of the gingival tissue, leading to exposure of the root surface, or where periodontal pockets exist.16 There are many factors which set off a chain of events which inevitably leads to this exposure, leaving the root surface susceptible to decay. Obviously, periodontal disease associated with loss of gingival attachment, coupled with xerostomia, poor oral hygiene, or a cariogenic diet, is destined to lead to root caries. Ravald and Birkhed found that smokers, in their study, had a significantly higher root caries prevalence and incidence than non-smokers. Smokers tend to have more exposed root surfaces, deeper periodontal pockets with bleeding on probing, and higher root plaque scores.33

Root caries is often defined by the extent or progression of a lesion. Many authors give treatment recommendations based upon the level of progression. For example, an incipient, inactive lesion would best be treated by prophylactic measures whereas a frank cavitation would require interceptive operative treatment.2,19,22,27 This case study deals mainly with frank cavitation warranting restorative treatment.


CASE STUDY


The patient is a Caucasian 75-year old male who is educated and is a community-dweller. He has been coming to the clinic for over 10 years and has maintained consistent dental visits. The patient presented with 9 active root caries lesions and 2 proximal active lesions. His condition would be classified as rampant root decay.


(illustration #1).

The root lesions were focused at the borders and underneath his 5-year old 8 unit maxillary anterior PFM bridge. The patient's maxillary posterior teeth had been replaced with a precision attachment RPD. He had all of his mandibular anterior teeth, with multiple restorations and gingival recession, but no root caries waspresent here. These teeth, however, are extremely susceptible to root decay, due to his gingival recession and plaque retention (illustration #1). The patient was in need of a mandibular RPD to replace his posterior teeth. His oral hygiene was poor and he had generalized gingival recession. Every root lesion was found on the abutment teeth of the fixed prosthesis. Virtually every surface associated with the fixed prosthesis was affected by root caries. It is not unusual that the root lesions are concentrated around the fixed partial denture since gingival recession and root exposure are often consequences of full coverage fixed prosthodontics due to difficulties in maintaining good oral hygiene. The buccal surfaces were more affected than the lingual surfaces.

The factors associated with this patient's root decay were his age, gender, poor oral hygiene, dietary habits, and highly restored teeth. The patient had no contributing medical history including a negative history for hyposalivatory medications. Xerostomia does not seem to be a factor in his root caries. Clinically, the patient had no subjective complaints of oral dryness, and objectively, the mucosa was quite moist. In addition, the patient had no history of smoking and had never been treated with radiation.

Treatment for this patient consisted of operative procedures to treat and arrest the rapid progression of his root caries. We felt this was the optimal treatment approach for our patient because it managed the patient in a conservative and preventive fashion. Based on the patient's age, financial considerations, and the investment of time needed to fabricate a new fixed prosthesis, it was decided that removing the caries to the best of our ability and restoring the lesions with synthetic materials, was the most appropriate treatment option. Other treatment options included removing the bridge, re-preparing the teeth to remove the caries and fabricating a new bridge. This is a treatment choice that needs to be discussed with each patient on an individual basis. The patient's PFM bridge was only five years old and structurally sound, so we felt it was best to attempt to keep it in place along with his precision RPD. A new prosthesis would require the patient to spend a much longer time in the dental chair. In addition, due to the high recurrence rate of root caries, replacing the fixed and removable prosthetics might also be contraindicated. Some of the patients' lesions were restored with composite (3M Z100) and others were restored with glass ionomer (ESPE Ketac-Fil Aplicap). The reason for using a fluoride releasing agent in some of the restorations was to observe the long term effects of one restoration versus another.

One tooth, the upper left canine, had a pre-existing post and core which was exposed clinically due to the deep extension of the caries. The caries was too extensive to remove from the upper left canine and first premolar without periodontal surgery, so a flap was opened to remove the inaccessible caries and the lesion was temporarily restored and the flap was closed. The area was later restored with glass ionomer (illustrations #2 and #3).



Illustration 2

Illustration 3

The results of this patient's treatment can be seen in illustration #4.


Illustration 4

Due to the opacity of this patient's FPD, it was very difficult to match a shade and therefore deliver favorable esthetics. However, this patient's lip line during smiling completely hides these restorations (illustration #5).

Illustration 5

In addition, it is interesting to note the continuing plaque buildup on the mandibular anteriors, where the patient is extremely susceptible to root decay (illustration #4). Unfortunately, even with proper oral hygiene instruction, it is often difficult to achieve acceptable levels of plaque removal. In such instances, it is imperative to have the patient on a frequent recall schedule.

To help prevent more recurrent decay, the patient's oral hygiene regimen was improved and he was placed on Prevident (Colgate Oral Pharmaceuticals, Canton, MA.), a prescription home fluoride brush-on gel program. The patient applies the 1.1% neutral sodium fluoride gel to all of the remaining natural teeth, for a minimum of three minutes, twice daily after brushing. Although the mandibular teeth do not exhibit frank carious lesions, the gel is applied as a preventive measure for all other teeth that have exposed root surfaces. There are many brands of fluoride gels, as well as different formulations, so each individual patient's needs should be considered.


DISCUSSION


There appears to be no difference in the pathogenesis or etiology of root and coronal caries.13,15,27,34 S. Mutans and Lactobacillus have been implicated in both lesions and high counts of both organisms can be found present in active root decay.10,14,27 The only difference is that less research has been done on root lesions as compared to coronal lesions so the microbial entities are not as well defined for root caries.9 It is, however, known that root lesions are invaded by microbes at an earlier stage than enamel lesions.29 It is imperative to act quickly with root lesions, because dentin is more soluble than enamel and these lesions progress very rapidly.13 This patient's case was especially difficult due to the location of the lesions at the margins of the fixed restoration. As a result, these lesions were inaccessible and difficult to restore.



Although molar teeth are the most susceptible and the incisor teeth the least susceptible to root caries, this patient's maxillary anterior teeth were affected due to his fixed prosthesis.31,33 The buccal surfaces were affected the most, which is consistent with evidence presented in research studies.31,33

Papas, Joshi, and Giunta found that the recurrence rates for root caries for each tooth were higher than for coronal caries. The rates varied from 6-12% with the central incisors the most affected for recurrence.31 Patients with coronal caries were 3.5 times more likely to have root caries than those who did not have coronal caries.31

When a patient presents with root decay, it is imperative to try and find the etiology of the patient's decay. With a detailed history and clinical exam, one can check salivary flow, medication history for hyposalivatory medications, and the possibility of a high sugar intake (sucking candies, sweetened tea or coffee, soft drinks, candy, gum, ice cream).13 It is very important to follow the patients dietary habits, which includes the nutrition history and food intake frequency. Root caries patients usually have a diet lower in crude fibers, phosphorus, protein, calcium, and magnesium and higher in sucrose, glucose, fructose and refined sugars.30 It has been documented that solid or sticky sweets are more harmful than sugars in solution such as soft drinks and coffee for the development of root caries.13 Hard candies and throat lozenges have often been found to be the culprits of root caries.13 This patient, as well as many other elderly patients, have a habit of sucking on hard candies throughout the day, which continually bathes the roots in a highly cariogenic medium. This habit is most certainly one of the factors involved in the etiology of his root decay. Faine and Persson found that the patients in their root caries study group had more frequent exposures to fermentable carbohydrates due to more frequent meals during the day, and also a higher average daily sugar intake than the control group.13

To rule out xerostomia as an etiologic factor, a salivary volume study can be performed. It might also be helpful to perform a buffering capacity test.13 A buffering capacity test may be important because if saliva lacks the basic ions to neutralize acids, the risk for root caries increases.13 Chewing gum can be used as an adjunct to preventive therapy because it has been shown to increase the plaque and salivary pH, thereby assisting in the neutralization of plaque acid formation.4,5,22,23,24,32

There are several types of restorations that may be used to restore these lesions and most of them are fluoride-releasing agents that have been shown to help prevent recurrent decay. These include glass ionomer with fluoride release, resin composite with or without fluoride release and amalgam with fluoride release. However, amalgam with fluoride release is not currently available in the United States.8 A restorative material for root lesions should have the following requirements: 1) good seal of restoration and tooth interface, 2) esthetically compatible to tooth structure, 3) ease of placement, and 4) continuous fluoride release.42 Amalgam is not the material of choice because it is extremely difficult to work with due to the shape and location of these lesions. However, glass ionomer is an excellent choice for the restoration of root decay due to its ease of placement and its release of fluoride. McComb describes the favorable properties of glass ionomers as being anticariogenic, antibacterial, adhesive to tooth structure, esthetically compatible, and undergoing minimal dimensional change.27 Composite resin, in comparison to glass ionomer cement, is not the treatment of choice for restoration of root caries in patients with inadequate oral hygiene. This is due to the fact that most conventional composites do not contain fluoride, and if they do, they do not demonstrate adequate release for significant caries inhibition.27 However, with new advances in dentinal bonding agents and acid-etching, composite resins have proven to be considered a treatment choice. Although these resins are not strong inhibitors of recurrent caries, they can still prevent external root surface demineralization.

Glass ionomer cements contain approximately 20% fluoride and tend to deliver fluoride levels at a high rate initially and then decrease to a lower constant rate for long periods of time.26,36,37 Unfortunately, most studies have been designed to evaluate glass ionomer cements or composite resins, as opposed to a study comparing the two materials in the restoration of root lesions. For this reason, Fejerskov feels a true comparison would be the only route to reach sound clinical conclusions.15

After restoring the patient's decay, it is essential to prescribe a fluoride formulation for the patient to use at home. It has been documented that fluoride programs may tend to enhance the conversion of active root caries lesions to inactive ones, rather than preventing the development of new lesions.33 Thus, these programs can be used as preventive methods instead of employing restorative procedures when frank cavitation does not yet exist.15,33 Long term effects of glass ionomer can be enhanced when fluoride applications are utilized because glass ionomer can take up the additional fluoride in the oral environment and release it at higher rates.17,18,21,35 Root lesions benefit from fluoride much in the same way as enamel does. However, the fluoride may be needed at higher concentrations for root lesions than for enamel.34 Fluoride inhibits mineral loss due to acids such as acetic, lactic, and propionic acid, which result from the fermentation of carbohydrates in the oral cavity. It also enhances remineralization of tooth structure.14 The mineral loss process can be up to twice as fast from the root as it is from enamel.14 This rapid progression, compounded with the thinness of tooth structure compared to the coronal tooth structure, is why it is so important to act quickly with these lesions.14,27 A common complication of restoration of root lesions is exposure of the pulp. Even a shallow lesion should be considered potentially deep considering the location of root lesions.14,28 An advantage of glass ionomer is that it does not cause pulpal irritation.28

Fluoride can be delivered to a patient in different forms including rinses, pastes, gels, varnishes, lozenges, tablets and drinking water. We chose to use a gel on this patient twice daily at home along with a fluoride toothpaste. In a study of seventy-one adults with at least one root caries lesion, the daily use of Prevident arrested 91% of the lesions over a twelve month period compared to 40% of the lesions in the control group.7 In addition to a daily gel, a professional application of a fluoride varnish can be applied twice a year.39 Although fluoride varnishes have been tested and successfully used clinically in other countries, they are not yet approved for use in the United States. Fluoride varnish is safe and easily applied to exposed root surfaces and it prolongs contact time between fluoride and teeth, thereby achieving deeper fluoride uptake.39 Other advantages of varnishes include adherence to tooth surface for a longer period of time, long term fluoride release, and a higher delivery of fluoride into cementum.3,6 When fluoride is applied, a new fluoroapatite mineral surface is formed which has a much lower solubility than the original hydroxyapatite mineral surface.38

In addition, to fluoride gels and varnishes, chlorhexidine gluconate (CHX) rinses, gels, and varnishes have been found to be highly effective against root caries due to its antimicrobial activity.19,43,44 Chlorhexidine gluconate gels and varnishes, however, are not currently available in the United States. Varnish as a delivery tool is very appealing over the rinse and gel counterparts because it is applied much less frequently (2x per year versus daily) and it can be applied precisely to the carious site without overflow onto healthy tissue. This overflow can cause a bad taste, irritation of the oral mucosa, and staining of the teeth and tongue.43


CONCLUSION


The management of root caries, and especially rampant root caries, can often be a very frustrating task for practitioners and their patients.27 Just as the etiology is multifactorial, so should the treatment be multifaceted in approach. Treatment decisions vary from patient to patient depending upon the severity of the case, extent of the lesion, the patients age and financial status, patient motivation, and the patient's esthetic concerns. Glass ionomer cements used as restorative materials can be extremely useful in delivering fluoride to a patient without having to worry about patient compliance.8 Whatever the treatment choice, the work should be done in a manner consistent with the rapid progression of root caries. It is essential that the patient be maintained on a frequent recall schedule in order to prevent recurrent lesions. In addition, the patient should maintain his/her home regimen of a fluoride gel, an appropriate diet, and an excellent oral hygiene program. It should be stressed to the patient that the best preventive measure against root caries is to maintain periodontal health and avoid apical migration of tissues.

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