Over the last few decades, the increase in dental caries in developing countries due to the consumption of processed food has led to the invention of atraumatic restorative technique (ART) as a means of delivering basic restorative procedures for underserved communities. Not only does this procedure save functional teeth from extraction, but it has also proven to be easy to execute with minimal equipment and monetary resources, which reduces the burden of oral health expenditure in underdeveloped and developing countries. ¹

Eventually, ART became the most researched technique to search for novel restorative material and minimal intervention approach strategies. ² ART not only proved to be easy to perform compared to conventional restorative methods, but it also proved to be less sensitive, less painful, and economical, while producing comparable beneficial results in the maintenance of viable teeth. ³ , ⁴ , ⁵

Glass ionomer cement is the only material that binds both enamel and dentin through chemical bonding; it also has had a similar thermal expansion to that of the tooth structure, induces absorption, and releases fluoride. They are also biocompatible and had established themselves as the material of choice for single surface restorations and decay limited to a dentinal extent. ⁶ , ⁷

The advancement of these new-generation glass ionomer formulations has resulted in the development of better properties, such as improved handling characteristics, decreased set time, increased strength, and increased wear resistance, making glass ionomer cements the material of choice for ART. ⁸

Although ART approaches using GIC are not recommended for proximal restoration due to loss of material by fracture and loss of bulk restoration related to material properties, the ART approach is still considered comparable to conventional amalgam restoration in single-surface restorations which can be carried out at economical cost with ease. ⁹ , ¹⁰ , ¹¹ , ¹²

Most ART procedures are performed on children in clinical and hospital settings, considering the costs of the treatment and the caries activity of the child; the most significant use of ART still exists in outreach and rural areas in underdeveloped and developing nations. Within these outreach initiatives and rural oral health services, the ART approach offers a viable approach to preserving functional teeth using minimal tools. ¹³ , ¹⁴ , ¹⁵ , ¹⁶

Therefore, this randomized clinical trial (RCT) was performed to compare the time required for cavity preparation, along with survival rates of high viscosity glass ionomer restorations using conventional cavity preparation and ART technique in primary molars over 3 years among children 6–9 years of age. The null hypothesis for this research was that there is no difference in cavity preparation time for these GIC restorations using traditional or ART approaches and survival rates over three years.

The current RCT was performed on 139 school children from government schools among the 6–9-year age group from the southern urban division of Bangalore, in the state of Karnataka, India. Upon approval from the Ethical Review Board of A. E. C. S. Maaruti College of Dental Science and Research Centre (Letter No. AECS/MDS/404/2007-08), the research study also got clearance to conduct from the Deputy Director of Public Instruction Office (DDPI) of Bangalore south and the schools concerned. The minimum number of participants required for each group for two-tailed tests calculated using the Cochrane formula was 28. After accounting for possible loss to follow-up, an additional 10% of participants were planned to be included in the required sample in each group. However, the final sample consisted of a total of 139 participants enrolled for research as this study was a part of the school oral health program. These participants were randomly allocated to two groups utilizing a randomization sequence was created using Microsoft Excel 2007 (Microsoft office, USA) and allocation concealment was achieved through Sequential Numbered Opaque Sealed Envelopes created by an independent statistician blinded regarding the nature and outcome of the study Figure 1. Figure 1

Flow diagram of methodology.

This comparative clinical study involved 139 participants aged between 6 and 9 years. Researchers were able to follow 92 participants out of 139 up to the proposed 3-year timeframe, resulting in 47 participants dropping out, i.e. 33.81%. Considering the age of the participants, it was observed that the majority of dropouts were observed in the 9-year age group, i.e. 32, whereas the 6-year, 7-year, and 8-year-old children showed a drop of three, three, and nine participants, respectively. Reasons such as exfoliation of the concerned tooth i.e. 31, extraction of the affected tooth i.e. 11, loss of contact i.e. three, and unwillingness to participate in subsequent follow-ups i.e. two were the reasons for drop-outs respectively Table 2and Table 3.{Table 2}{Table 3}

The final analysis of the study consisted of 92 participants which consisted of 32 males and 22 females in the ART group while 22 males and 16 females in the conventional group respectively (P = 0.896).The mean age of the study participants in the ART group was 8.31 ± 0.93 years and that in the conventional method group was 8.52 ± 0.80 years (P = 0.257) [Graph 1] and Table 4.[INLINE:1]{Table 4}

While considering the percentage distribution of maxillary and mandibular teeth in both the groups, the ART group consisted of 24 (44.45%) teeth belonging to a maxillary arch and 30 (55.55%) belonging to the mandibular arch. Whereas the conventional group consisted of 24 (63.16%) teeth belonging to the maxillary arch and 14 (36.84%) teeth belonging to the mandibular arch Table 5.{Table 5}

An estimation of the time taken to complete a GIC restoration using both methods suggested that completing a GIC restoration using a traditional method takes approximately 13.15 ± 1.32 min, while completing the ART restoration takes 16.48 ± 2.02 min. Application of Unpaired t-test between the time required by the two methods showed a highly statistically significant difference between both the methods (P ≤ 0.001) Table 6.{Table 6}

The log-rank test shows that there is an overall statistically nonsignificant difference (i.e. χ ²= 1.295, P = 0.255) in the overall survival distributions between the two intervention groups, i.e. ART and conventional method Table 7.{Table 7}

From our Kaplan–Meier survival curve, we can see that in the GIC restoration with conventional methods, the cumulative survival proportion tends to be higher than restorations performed using ART in all the three follow-up periods (i.e. 95% and 100% at 12 months, 74% and 61% at 24 months, and 48% and 39% at 36 months in conventional and ART group, respectively). Although it is evident that GIC restorations carried out using conventional methods seem to survive for a longer period, it still does not seem to survive significantly much longer compared to those restored with using the ART method (P = 0.255) [Graph 2].[INLINE:2]

Dental caries which is considered a preventable disease is among one of the most prevalent serious public health problems. Many times, the caries process frequently progresses beyond the reversible stage and their impact on individuals and communities in terms of pain, suffering, impairment of function, and reduced quality of life, is considerable. ¹⁹ , ²⁰ Although many countries run various programs to tackle this problem, still preventive programs are slow in reaching populations that need them the most. Even if the cost of many preventive programs is low, they rarely reach the funded priority list of developing countries. ²¹

Modern restorative care of carious lesions is based on monitoring early lesions to assess progression, accompanied by a minimal intervention approach, is costly, and requires extensive dental care setups, which might sometimes not be available in the case of outreach settings ²² , ²³ While ART which was developed to provide solutions to restorative treatment needs in underprivileged and distant populations, is a simple and economical method that is different from routine operative treatment and significantly impacts restorative needs at community levels. ²⁴ , ²⁵

The current study is one of the few studies, which compare the survival of GIC restorations carried out using ART and conventional methods over a long period, i.e. 3 years. ART which has an additional benefit of a children-friendly technique over conventional technique as it has pain-free nature and has a greater level of acceptance than conventional treatment makes it worth assessing its survival rates. ³

The study also demonstrated the excellent 1-year survival rate in both ART approach and conventional method using high viscosity GIC, i.e. above 95%, which is in accordance with Holmgren and Frencken 2000, and Yip et al. 2002. ²⁶ , ²⁷ However, the conventional method of restoring teeth exhibited a slightly higher survival rate as compared to the ART technique at the end of the 2 ^ndand 3 ^rdyear, with clinically and statistically non-significant difference between these two-time intervals which is in accordance with the results obtained by Yu et al., 2004, Hu et al. 2005. ²⁸ , ²⁹ This makes the ART treatment as beneficial as conventional technique in providing treatment to an individual with restorative need in the tooth with minimal decay, who are not able to access the dental care settings as the procedure involved in this study was similar to that used in outreach setups.

Along with the GIC restoration survival rates, our study also found that the operative time needed for the ART procedure is longer than the conventional method, similar to what Kikwilu et al., 2001, and Honkala et al., 2003 found. ³⁰ , ³¹ This may be attributed to technique sensitiveness of the ART which requires the use of only hand instruments such as hatchets and spoon excavators of varying sizes for caries excavation and cavity preparation. The use of hand instruments requires the utmost technical skill and expertise to assess demineralized tooth structure on visual and tactile sensation. Care also has to be taken while using force for caries excavation to avoid unnecessary damage to the underlying structures. Hence, this kind of highly controlled excavation procedure requires more amount of time which also depends on the type of tooth being restored, i.e. primary or permanent, due to their structural and morphological differences. ³²

Although there were certain limitations of the study like the current study only involved single-surface restorations and did not control for participants' behavior, habit of bruxism, fluoride exposure, the size of the restoration, and oral hygiene practices which could influence the failure of restorations. Still, the study has a strong backbone of long-term assessment of survival rates of these restorations carried out by these methods.

The reason for choosing the 6–9 years of age group was that teeth will have been in the oral cavity for long enough to experience dental caries at this age, and would stay in the oral cavity for long enough before we complete the follow-up.High drop-out rates, i.e. 33.81 percent observed in our study, are mainly attributable to the loss of the affected teeth by exfoliation or extraction and mostly observed in children aged 8 and 9 years as they undergo a transition from primary molars to secondary molars. Apart from this, reluctance to participate in further follow-up and loss of contact was a minor cause for dropouts.

Success rates of ART which was almost similar as compared to conventional methods with statistically non-significant differences demonstrated the feasibility and ease of carrying out the ART technique even in very young children. This technique not only proved to be a method of high level of acceptance in children being less painful and a minimally invasive approach, but also proved itself to be a potential method to be used both in clinical and outreach settings irrespective of child's age.

The study also highlighted the finding that if appropriate care has been taken to limit the use of ART to only minimally decayed teeth and particularly to that for single surface restoration with good caries removal and restoration placement may result in a good clinical outcome as compared to that of modern restorative procedure with drill technique.

The current study at the end of 1-year GIC restoration by both methods showed good survival rates. Even though the survival rate of high viscosity GIC restorations were slightly more for conventional methods as compared to those restored using ART after 3 years, the difference in survival by both methods was statistically not significant. Despite some limitations of the study, the study still proves that GIC restorations using ART can be carried out with ease and can give comparable survival results both in clinical and outreach settings.

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Conflicts of interest

The authors of this manuscript declare that they have no conflicts of interest, real or perceived, financial or nonfinancial in this article.