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ART and Conventional Root Restorations in Elders after 12 MonthsFaculty of Dentistry, University of Hong Kong, 3/F, Prince Philip Dental Hospital, 34 Hospital Road, Hong Kong SAR, China Correspondence: * corresponding author, edward-lo{at}hku.hk
Successful use of atraumatic restorative treatment (ART) in children has been reported, but little information is available regarding its use in older adults. The hypothesis of this study was that survival rates of root restorations placed by both ART and the conventional technique were similar. Root-surface caries lesions in 103 institutionalized elders in Hong Kong were treated randomly by either: (1) the conventional approach—caries removed by dental burs, and the cavity filled with light-cured resin-modified glass ionomer; or (2) the ART approach—caries removed by hand instruments, and the cavity filled with chemically cured high-strength glass ionomer. In total, 84 conventional and 78 ART restorations were placed. After 12 months, 63 conventional and 59 ART restorations were reviewed, and the respective 12-month survival rates were 91.7% and 87.0% (p > 0.05). It is concluded that the survival rates of both types of root restorations were high and similar.
Key Words: root caries • atraumatic restorative treatment • glass-ionomer cement • clinical trial • Chinese • age • restoration survival
It is projected that the world’s population aged 65 yrs and above will increase from 550 million in year 2000 to 973 million in year 2030, i.e., from 7% to 12% of the total population worldwide (CDC, 2003). There has been a significant reduction in the prevalence of edentulism among elders worldwide in recent years (Petersen, 2003), and people are retaining more natural teeth into old age. In a 10-year longitudinal study of tooth loss and dental caries in a random sample of elders in Sweden, the mean number of retained teeth in the 65-year-olds had increased from 18.8 in 1987 to 22.5 in 1997 (Fure, 2003). It has been reported that the incidence of root-surface caries increases with age (Griffin et al., 2004). An oral health survey conducted in Southern China showed that the prevalence of decayed/filled roots was 37% in elders aged 65–74 yrs, compared with 12% in 35- to 44-year-olds (Lin et al., 2001). With an increase in the number of elders and the retention of more natural teeth into old age, there is an increasing need for preventive and restorative dental services among older adults, especially for underserved populations, such as institutionalized elders (Chalmers et al., 2002; Petersen, 2003). Since financial, access, and motivational barriers are common among elders living in various institutions, alternative dental care service delivery approaches, such as outreach services, are needed (Guay, 2004; Lo et al., 2004). Restorative treatment for root caries is often difficult. Compared with coronal caries, little information on the success of the current methods of treating root caries is available (König, 2004). In the treatment of root-surface caries lesions, the conventional approach of ‘drilling and filling’ is commonly adopted. This approach requires the use of power-driven dental rotary instruments for the removal of decayed dental tissues and for cavity preparation. Local anesthetic injection is usually required to allow the procedures to be performed painlessly. Recently, glass-ionomer materials have become popular for restoring cavities in root surfaces, due to their better esthetics and ability to bond to the tooth (Burgess and Gallo, 2002; König, 2004). The Atraumatic Restorative Treatment (ART) approach has been shown to be useful for treating tooth decay in children in developing countries and among disadvantaged communities (Massara et al., 2002; Frencken et al., 2004). ART has also been used in other populations, including the home-bound elders and people living in nursing homes (Pilot, 1999). The survival rates of single-surface ART restorations placed in permanent teeth of children have been promising, being as high as 90% after 3 yrs reported in studies in Zimbabwe (Frencken et al., 1998) and in China (Holmgren et al., 2000). However, little information on the use of the ART approach to treat root caries among elderly people is available. This study aimed to investigate the effectiveness of using the ART approach in treating root caries in elders living in residential and nursing homes. The hypothesis of this study was that survival rates of root restorations placed by the ART and the conventional technique were similar.
The study population consisted of elders living in 21 residential and nursing homes for the aged in Hong Kong, who were served by an outreach dental team (Lo et al., 2004). Elders aged over 60 yrs, having basic self-care ability, and with root caries present were invited to participate. The study protocol was approved by the Ethics Committee of the Faculty of Dentistry, University of Hong Kong. Informed consent was obtained from all patients before commencement of the study. All clinical examinations were conducted where the subjects resided. The subjects were examined in a portable dental chair, and an extra-oral portable clinic light provided adequate illumination. Plaque and calculus obscuring visual inspection of root surfaces were removed by means of hand instruments and oral hygiene aids. Root-surface caries was diagnosed through visual-tactile examination (Banting, 2001). A sharp explorer was used to test for softness of the dentin at the base of any discolored cavity on the root surface. Caries was recorded when the dentin could be penetrated with light force. Root caries lesions 1 mm or more in depth, as measured with a marked periodontal probe on teeth not indicated for extraction, were included in this study. Lesions involving or judged to be very close to the dental pulp were excluded. We tossed a coin to allocate the selected lesions randomly to receive one of the two study treatments: restorations placed by the conventional or by the ART approach. For patients who had 2 root-caries lesions, both types of treatment were provided. The treatment assignment procedure was repeated if there were more than 2 lesions in a subject. In determining the sample size, we regarded a difference in restoration survival rate of 15% or more as clinically significant. Using an 80% power and a 5% statistical significance level, we found that around 80 restorations in each group were required. All restorations were placed, in early 2003, by one experienced dentist, aided by a chairside assistant. When a cavity was prepared by the ART technique, only hand instruments were used in the removal of decayed dental tissues. Attempts were made to remove all the soft dentin from the cavity. Cotton rolls and gingival retraction cord were used when necessary for field isolation and moisture control. The prepared cavity was cleaned and then conditioned for 10–15 sec with the liquid of the glass ionomer, diluted with an equal amount of water. The prepared cavity was cleaned with water, dried, and then restored with a high-strength chemically cured glass-ionomer material (Ketac Molar, 3M ESPE, Seefeld, Germany). We used a clear cellulose matrix when building up the contour of the root. When a caries cavity was treated with the conventional approach, local anesthesia was given when required. Cotton rolls and gingival retraction cord were used for field isolation and moisture control. Decayed tooth tissues were removed by means of dental burs until the floor and walls of the cavity were found to be hard. The cavity was washed with water from a 3-in-1 syringe and then dried. The prepared cavity was conditioned with polyacrylic acid for 10–15 sec, washed, dried, and restored with a resin-modified glass-ionomer material (Fuji II LC, GC Corporation, Tokyo, Japan). A curing light was used, and the restoration was polished during the same visit. Status of the restorations was assessed at six-month intervals by a dentist who was not involved in the provision of the treatments, and who did not know which technique had been used in placing the restoration. The evaluation criteria used in most ART studies were adopted (Frencken et al., 1998). The presence and status of the restoration, and the need for replacement or repair, were assessed. Sound restorations or restorations with marginal defect or wear less than 0.5 mm, measured by the ball tip of a CPI periodontal probe, were classified as having ‘survived’. The modified US Public Health Service (USPHS) criteria for evaluation of restorative materials (Ryge, 1980) were also used to assess the status of the restorations with respect to retention, marginal integrity, marginal discoloration, recurrent caries, anatomical form, and surface texture. The examiner (YL) was trained and experienced in assessing restorations using the above two sets of criteria (Lo et al., 2001). Duplicate examinations were carried out on 10% of the patients for the assessment of intra-examiner reproducibility throughout the study.
Data Analysis
In total, 162 restorations, 78 ART and 84 conventional, were placed in 103 elders (72 women and 31 men), with a mean age of 78.6 yrs. The mean number of teeth present in the patients was 12.8, and the mean number of decayed or filled teeth (excluding root caries) was 1.0. The vast majority of the elders (88%) received either 1 or 2 root restorations. Only 3 of the restorations involved multiple surfaces; the others were single-surface restorations, mainly on the distal or the mesial surface. After 6 mos, 64 ART and 68 conventional restorations were reviewed. After 12 mos, 59 ART and 63 conventional restorations in 77 elders were examined. The dropout rates of patients and the 2 types of restorations were similar, around 25%. The reasons for dropout were that the patients had died, were too ill to be examined, or were not at the home on the examination day. Total agreement on the survival or failure of a restoration was achieved in the duplicate examinations.
At the 12-month examination, 66.1% of the ART restorations were assessed as being ‘present and sound’, and 20.3% as having a ‘slight marginal defect or wear’, according to the ART criteria (Table 1
Results of the life-table survival analysis showed that the 12-month cumulative survival rates for the ART and conventional restorations were 87.0% and 91.7%, respectively (Table 3  ). The difference between the two survival rates was not statistically significant (Gehan’s Wilcoxon test, p = 0.30). Furthermore, there were no statistically significant differences in the survival rates of restorations placed in different tooth surfaces (mesial/distal vs. buccal/lingual) or in different tooth types (anterior vs. posterior).
This study is one of the few that have assessed the use of ART to treat root caries in elders in an outreach dental service. The clinical status of root restorations placed by either the ART or the conventional approach was compared directly in this study, and their survival rates over the 12-month period were similarly high. This study adopted a double-blind design in which neither the elders nor the examiner was informed of the technique which had been used in the placement of a restoration. Blindness was possible because tooth-colored glass-ionomer material was used in both techniques, and the restorations had similar appearances. While the elderly patients had been given details of the study, it did not enable them to differentiate between the two types of restorations. To avoid having a high patient dropout rate due to poor general health or death, we excluded frail elders in the nursing homes. Only patients having self-care ability for normal basic daily activities, including toothbrushing, were included. After 1 yr, around 60 (75%) of the restorations in each treatment group were evaluated. This was considered adequate for proper statistical analysis, since this sample size has an 80% power to detect a difference of 16% in survival rates between groups. In the present study, around 10% of the restorations in both the ART and the conventional approach groups failed, mainly having been lost, most likely due to difficulty in achieving good moisture control under field conditions, especially in circumstances where there was exudation of gingival crevicular fluid or blood. This would have led to a weakening of the adhesion of the glass-ionomer restoration to prepared root cavities. At the 12-month examination, caries related to root restoration was detected in 3 teeth, 2 in the ART group and 1 in the conventional group. Glass ionomer being a fluoride-containing restorative material may have a cariostatic effect, but it is not known whether the level of fluoride release is sufficient for inhibiting demineralization (Pereira et al., 1998). The secondary caries detected might also have developed from residual caries left in the prepared cavity, because the use of hand instruments in the ART technique may result in some carious tooth tissue being left behind (van Amerongen, 1996). Complete removal of carious tissue is still recommended prior to the placement of an ART restoration (Weerheijm et al., 1999). In this study, the 12-month cumulative survival rate of root restorations placed by the ART approach (87.0%) was comparable with that of the conventional restorations (91.7%), and higher than the 79% one-year survival rate reported in an earlier study in Finland (Honkala and Honkala, 2002), which included only 19 ART restorations in 11 subjects. The high survival rate of the ART root restorations in this study is comparable with those of single-surface ART coronal restorations placed in children (Frencken et al., 1998; Holmgren et al., 2000). As in other studies (Lo and Holmgren, 2001; Honkala and Honkala, 2002), little pain was experienced by the patients during placement of an ART restoration, and no local anesthetic was required. In addition, the ART approach has other advantages for use in outreach dental services, because it requires only a few hand instruments for the successful placement of root restorations. It was concluded that, in institutionalized elders, the 12-month survival rate of glass-ionomer restorations placed on root surfaces by the ART approach was high and comparable with that of conventional restorations. It is planned for the root restorations in this study to be followed for 36 mos. If the survival rate of the ART restorations remains comparable with that of conventional restorations, then the ART approach can be considered for use in outreach dental services to restore root caries lesions in institutionalized elders and possibly other special-needs groups.
This study was supported by the Hong Kong Research Grants Council (Ref. HKU 7244/02M). Received for publication August 3, 2005. Revision received February 21, 2006. Accepted for publication May 16, 2006.
Journal of Dental Research, Vol. 85, No. 10,
929-932 (2006) This article has been cited by other articles:
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