a new method for treating dental caries that involves no drill , running water or electricity was presented at the headquarters of the world health organization on world health day in 199412 .
this approach , called " atraumatic restorative treatment " ( art ) consists of manually cleaning dental cavities with hand instruments and restoring them with an adhesive fluoride - releasing material1 .
since that time , art has been developed into a reliable alternative to restorations performed even at well - equipped dental clinics2,18,29 .
this technique involves removal of only carious tooth structures with hand instruments , and the use of glass ionomer cements ( gics ) as filling material12 . in spite of the fact that first results of art approach were more promising , especially with single - surface restorations after 1 year
, material loss ( wear / dissolution ) was more common in gic material in the following years15,21,22,26 .
subsequently , some improvements have been performed to increase the resistance and manipulation of gics due to their moisture sensitivity and low wear resistance28 .
although conventional gics have relatively poor mechanical and adhesive strengths , their satisfactory biological features , ease of use , and low costs are distinct advantages26 .
further development of gics focused on a higher - powder - to - liquid ratio , and smaller glass particles leading to high viscosity .
therefore , more strength gics ( non - metal - reinforced : fuji ix , ketac molar ; metal - reinforced : hi dense ) , which should be packable as amalgam was found , and revealed enhanced flexural strength characteristics14,17 . when compared to early field trials , newer art studies using specifically marketed gic material have shown promising results for the restoration of single - surface caries lesions in permanent teeth11 .
although the success rate reported by most studies is approximately 90% for single surface restorations in permanent dentition , the cumulative survival percentage seems considerably variable according to evaluation periods , materials and geography : 66.1% for 6 years in syria13 ; 72.3% for 6 years in tanzania22 ; 92.5 to 94.9% for two years in latvia29 ; 93.3% for two years in filipines24 , 76% and 59% of the small and large restorations for six years in china19 ; and 66% for two years in mexico20 . on the other hand ,
the success rates have been much lower for multi - surface molar restorations ( 55% to 75% ) , and found to be closely related with the operator , the materials used , and the art method of cavity preparation10 .
materials have recently led to varied alternatives to art field trials7,9,10 . of these , light - curing materials , such as resin modified glass ionomers ( rmgic ) , which can easily be cured in rural conditions by a rechargeable curing device , a light emitting diode ( led ) , may be an alternative to gics in non - electrical conditions7 .
the objective of this 24-month - follow - up study was to evaluate , using the united states public health service ( usphs ) and art criteria , the in vivo performance of two restorative materials - one hsgic and one rmgic - cured with led in field conditions .
the null hypothesis was that there is no difference in the success rate between restorations placed using the art approach using either gic or rmgic after two years .
the target group consisted of 7-to-12-year - old children with dental caries in permanent teeth .
their oral hygiene was very low , and dft and dmft were 5.2 and 1.8 , respectively .
the selected children and their parents were informed of the nature and procedures of this study by the school authorities .
the study protocol was approved by the national educational management of diyarbakr ( 2002 ) .
thirty - seven children who had one or two bilateral matched pairs of carious posterior permanent teeth that required either class i or class ii restorations were selected . in this procedure ,
intraoral assignment of the material to the teeth was done by the loss of the coin as seen in mandari , et al.23(2001 ) .
a random number table was used to determine which tooth of a pair was to be restored with either the control [ hsgic - ketac molar ( 3 m espe , st paul , mn , usa ) ] or the test [ rmgic - vitremer ( 3m / espe dental products , st .
one experienced dentist performed all treatment procedures during 2 months in school premises ( td ) .
he had previously trained in a previous art field - trial for 4 years in the same region .
the placement of art fillings closely followed the procedures described by frencken , et al .
when preparing a carious tooth to receive an art restoration , the cavity entrance was widened , if required , with a small hatchet before the removal of soft caries with sharp spoon excavators .
prior to being filled , the prepared cavity and adjacent enamel were cleaned with a dentine conditioner , which was the mixing liquid supplied with the glass ionomer cement itself .
the liquid was removed after 10 - 15 s with a wet cotton pellet and the cavity was then blotted dry .
the glass ionomer cement was mixed by hand according to the manufacturer 's instructions , and applied to the cavities with the " press finger " technique .
rmgic material was applied as another restorative option using the art technique as follows ; ( i ) the operated quadrant was isolated with cotton - wool rolls , ( ii ) after cleaning the tooth surface and widening the entrance of the lesion , soft dentinal caries was firstly removed from the floor of the cavity , and secondly from the dentin - enamel junction . if the carious lesion extended deep into the dentin , a thin layer of a calcium hydroxide liner was carefully placed in the bottom of the cavity , ( iii ) the surface , including dentinal tissue , was conditioned with a conditioning - solution ( vitremer primer/ 3 m espe ) provided by the manufacturer , using an adequate - sized moistened cotton pellet , ( iv ) the material was mixed according to the manufacturer 's instructions with the proportion of 2 to 3 powder measures for every liquid drop . then , newly mixed material was squeezed into the cavity . (
v ) before light - curing , to avoid air bubbles , to adapt the material into the cavity , and to remove excessive material , initial finger pressing coated with petroleum jelly was performed , and a slight pressure was applied .
( vi ) since the material would be too hard to be trimmed after curing , an occlusion adjustment was made just before curing , and to provide a smooth surface , finger pressing was repeated before curing .
( vii ) for adequate polymerization , at least 30 s of light - curing with led ( light emitting diyote - elipar freelight/ espe , germany ) was applied .
( viii ) to eliminate surface roughness , a hatchet was used with carvingmotion . finally , a surface protector solution provided by the manufacturer was applied and cured .
the restorations were evaluated in accordance with both usphs and art score systems at baseline , 6 , 12 and 24 months ( figures 1 and 2 ) . for art rating procedures ,
the evaluations were carried out in the children 's own school environment by two calibrated dentists , using a ball - ended - who probe .
two blinded experienced dentists ( md and iy ) , evaluated the restorative materials at baseline , 6 , 12 and 24-month periods .
evaluation consistency was assessed in a sample of 30 restorations ( 15 rmgic and 15 gic ) in 12 children at baseline . for the usphs - scoring procedure ,
the mean values of cohen 's kappa for art and usphs criteria ( examiner 1 vs. 2 ) were 0.92 and 0.87 , indicating good inter - examiner agreement .
the basic disagreement was usually seen in the presence and degree of marginal discoloration of rmgic restorations for usphs criteria . according to the art score system ,
a restoration was assessed as successful if it was recorded as score 0 , 1 or 71 .
all data were analyzed using the graphpad prism v.3 pc software ( graphpad software inc .
diego ca ) . for testing differences in both rmgic and gic groups between baseline , 6-month , 12-month , and 24-month results ,
mc nemar 's test was used with significance set level at p<0.05 . to evaluate the differences between rmgic and gic groups , and also between single and two surface restorations ,
fifty - two were restorations with rmgic and 39 were restorations with hsgic , in that 21 and 17 had two surfaces , respectively . at baseline ,
91 restorations ( 37 children ) were assessed . out of 91 restorations , 3 ( two with rmgic , one with hsgic )
while all restorations were present in the rmgic group , a total of 6 ( all in the two - surface group ) hsgic - restorations were lost after 24 months ( according to " retention " criteria of the usphs - criteria system ) .
with respect to recurrent caries and/or the occurrence of new caries between teeth filling interfaces , all restorations in both groups were assessed as perfect at baseline , 6 and 12-month study periods , but not at 24 months .
a total of 8 restorations in the hsgic group showed the occurrence of new caries between tooth restoration interfaces in this recall period .
the difference between both groups was statistically significant ( p= 0.002 ) the percentage and number distribution of rmgic and hsgic groups with respect to the art scoring system is presented in table 1 for both single- and - multiple - surface restorations , separately , and figure 3 .
irrespective of the surface number , 100% of rmgic and 63.2% of hsgic restorations were classified as successful after 24 months .
the difference was statistically significant ( p= 0.0001 ) . in the comparison of single- and - multiple - surface - rmgic restorations after 6 , 12 and 24 months
, a statistically difference was observed at both 12 and 24months ( for both observation periods , p<0.002 ) . as a general rule ,
singlesurface restorations had a significantly better clinical performance than did multiple - surface restorations , especially for the hsgic group .
when comparing both groups in each study period , a clear difference was observed in both 12 ( p= 0.05 ) and 24-month ( p= 0.02 ) results for single - surface restorations .
however , a statistically significant difference was definitely found in either observation period for multiple - surface restorations ( for 6 months , p<0.011 ; for 12 months , p < 0.008 ; and for 2 months , p < 0.0001 ) .
distributions of the retained rmgic and hsgic restorations among the usphs criteria , including marginal discoloration , anatomic form , and marginal adaptation , are shown in table 2 . in the overall results ,
multiple - surface restorations were worse than single - surface restorations for both groups according to marginal discoloration .
when comparing both groups , the statistical difference was only found at 24 months for surface restorations , and it was in favor of the rmgic group ( figure 4 ) .
a statistically significant difference in the loss of marginal adaptation between rmgic and hsgic - restorations at all evaluation periods for multiple - surface ( see table 2 ; at 6months , p<0.04 ; at 12 months , p < 0.03 ; at 24 months , p<0.007 ) , but not for single - surface groups .
contrary to rmgic restorations , surface pitting at probing was the most common sign of surface loss in gic group irrespective of single or multiple surface restorations . in comparison of both groups with respect to single surface restoration
however , the most pronounced difference was found at 24 month recall ( p<0.001 ) . for multiple surface restorations deteriorations in gic restorations did increase with time , and it was statistically significant for all recall periods except of that in 6 months . the null hypothesis that there is no difference in the success rate between restorations placed by the art approach using hs - cics and rmgics after 2 years was thus rejected .
the results of this study showed that hsgic restorations were limited as art restoratives , especially in multiple surfaces .
also , rmgics showed a better clinical performance than that of hsgics , irrespective of the surface numbers for 24 months .
as seen in table 1 , total success rates of rmgic for single- and multiple - surface restorations were 100 and 100% , respectively .
clearly , the 100% total retention rate of rmgic materials with the art technique is undoubtedly the greatest success rate ever seen
. it has been demonstrated that the superior clinical performance of light - cured materials over those of chemical curing points out that they technically are less sensitive than self - cure materials because once irradiated , they do not require protection from moisture4 .
croll , et al.5 were the most enthusiastic of all the authors who generally support the use of rmgics and light - curing hsgics rather than those with chemical curing . in this respect
, it could be argued that rmgic materials with superior physical properties over gics and controlled light curing can be recommended as an alternative material to be used for art field trials . in parallel with this assumption , donly ,
et al.6 concluded that in clinical terms rmgics functioned as well as amalgam for class ii restorations in primary molars .
concomitantly , rmgics exhibited significantly less enamel demineralization than amalgam at restoration margins , and , also , lower caries occurrence between tooth filling interfaces4,6 .
however , our 24-month results concerning both single - surface ( 100% ) and multiple - surface ( 100% ) rmgic art restorations ( 100% ) are very promising , with a success rate of over 98% , which is the best retention rate reported until now for a two - year - follow up period .
the newer hsgics marked specifically for the art approach appear to be promising for the restoration of single - surface - caries lesions in permanent teeth27 .
after 2 to 3 years , the success rate reported by most studies is approximately 90% for class i , and class - v - single - surface restorations ; the rate for recurrent caries is approximately 2% .
one recent 3-year study reported higher survival rates for small restorations ( 92% ) than for large restorations ( 77% ) 16 .
studies involving earlier formulations of hsgic showed slightly lower success rates ( with a higher incidence of caries ) , as did restorations placed in children and in occlusal rather than nonocclusal surfaces21,26 .
, a success rate of 80.9% for single - surface - gi restorations seems to be lower than the recent two - year - studies by ho , et al.15 in a clinical setting ( 89% and 93% for chemfil sup and fuji ix , respectively ) , and by mandari , et al.22 in a field setting ( 96% ) .
the reason for this low success rate as seen in the present study can be due to the participation of younger children , who are considered more difficult for restoring teeth ; unavailability of a trained assistant used in many art field trials to help the experienced dentist ; and partially to the presence of large cavity size in many of the teeth restored19,23,28 . very few studies have reported success rates for class - ii - multi - surface restorations in permanent teeth .
after one year , one study of a hsgic reported a success rate of 93 % 3 .
another recent study of ketac - molar found that eight out of 14 class - ii restorations were successful after 3 years16 .
in general , the success rate of class - ii restorations after 24 months varied from 39.5 to 45.6% in both primary and permanent teeth , respectively . the 24-month - retention rate of multiple - surface - hsgic restorations ( totaling 41.2% ) is comparable to that of the permanent teeth .
although the evidence supporting minimal restorative interventions resembling art cavities shows that minute cavities can be successfully treated , material - related failures are not size dependent , and low - strength materials such as hsgics seem to generally fail with respect to wear and tear in whatever cavity shape preferred28 .
accordingly , in a recent study , fracture\marginal defects and loss of material were among the most common reasons of failure in an art group , even when the shape of the cavities had been modified . from these results , it may be concluded that the search of a new material that is stronger than hsgics has become apparent22 . in some field trials
, it has been clearly shown that amalgam is a suitable art and/or manual restorative treatment ( mrt ) material for extensive occlusal lesions in high - caries populations , especially in young children ; the secondary caries occurrence has been found to be significant when compared to hsgic counterparts [ 2% of glass - ionomer vs 10% of amalgam restorations]22 .
ultimately , art materials were used to remineralize the carious tissue remaining after hand excavation , and to prevent secondary caries8,25 . in this respect , fluoride release and chemical adhesion is , of course , mandatory for future materials to be used in further art studies , and clinical and field settings using adhesive materials with physical properties superior to the current hsgics , such as compomers ( polyacid modified composite resin ) and rmgics , would be meaningful . in a recent study , ersin , et
al.10 have tried to compare the effectiveness of a composite resin / dentin bonding system following an art approach , as compared with hsgics .
although their study was performed in primary dentition , after 2 years , the success rate of the composite material was found to be promising for further art studies [ 96.7 percent of the class - i - hsgic restorations , and 91 percent of the resin - based composite restorations ] . clearly ,
the most remarkable , but not significant , result of this study was that the 24-month survival rate of the class - ii - composite restorations is much higher than that of hsgics ( 82% vs. 76.1% ) compared to the results seen in class - ii cavities .
on the other hand , this logical application with composite resin according to an art approach leads to a new chance of bonding the filling materials to the art - hand - made cavities , using non - rinse - one - bottle bonding agents in field conditions .
one of the criteria used in the present study has been applied in most other art studies in permanent dentitions11,16,18 .
however , the usphs criteria are usually used to assess restoration survival in various studies .
holmgren , et al.16 applied both the art and usphs criteria to the same art restorations in permanent teeth , and reported no significant differences in survival outcomes of art restorations between the two sets of criteria .
lo , et al.20 suggested that the art criteria are more stringent than the usphs criteria . in the present study ,
the main reason was to compare the clinical performance of rmgic material with the literature indicating a lack of previous reports on the issue of rmgic with an art approach . in only one 24-month - study ,
the success rates observed using the usphs criteria were close to , but lower than those observed using the art criteria for two hsgic restorative materials ( 98.1% and 100% , and 96.1% and 96.1 % for chem flex and fuji ix gp with usphs and art scoring criteria , respectively)19 .
this observation is in line with our study whereby , according to " retention criteria " of the usphs system , the present results are higher than those obtained by the success - rate of art ( 100% and 80.9 % with usphs and art , respectively ) ( figures 3 and 4 ) .
it may reasonably be assumed that both criteria used in this study are to a large extent comparable to each other for evaluating art fillings in field conditions .
the results of the present study indicate that rmgic cured by chargeable curing units would be able to provide a reliable alternative over glass ionomer materials in art - field - trials .
 objective : the purpose of this study was to investigate the clinical performance of high - strength glass ionomer cement ( hsgic ) and resin - modified glass ionomer ( rmgic ) in single and multiple surface carious cavities in the field conditions.material and methods : a split - mouth design , including ninety - one fillings placed on contra lateral molar pairs of 37 children , was used in permanent dentition . as filling materials , a hsgic ( ketac molar/3 m espe ) and a rmgic ( vitremer/ 3 m espe ) were used with the atraumatic restorative treatment ( art ) . 
 baseline and 6 , 12 and 24-month evaluations of the fillings were made with standard - art and usphs criteria by two examiners with kappa values of 0.92 and 0.87 for both criteria.results:according to the usphs criteria , the retention rates of rmgic and hsgic restorations were 100% and 80.9% for single surface , and 100% and 41.2% for multiple surface restorations after 24 months , respectively . 
 irrespective of surface number , rmgic was significantly superior to hsgic ( p= 0.004 ) , according to both standard - art and usphs criteria.conclusion:the results indicate that rmgic may be an alternative restorative technique in comparison to high - strength gic applications in art - field - trials . 
 however , further clinical and field trials are needed to support this conclusion . 
INTRODUCTION
MATERIAL AND METHODS
RESULTS
DISCUSSION
CONCLUSION