Clin Oral Invest DOI 10.1007/s00784-014-1374-3
ORIGINAL ARTICLE
Success rates of manual restorative treatment (MRT) with amalgam in permanent teeth in high caries-risk Filipino children I. M. Schüler & B. Monse & C. J. Holmgren & T. Lehmann & G. S. Itchon & R. Heinrich-Weltzien
Received: 28 December 2013 / Accepted: 20 November 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Objectives The objective of the study is to evaluate the success rate of amalgam restorations in manually prepared cavities under field conditions within a comprehensive schoolbased oral health-care program in high caries-risk children. Materials and methods A total of 1322 restorations were placed in the permanent teeth of 619 high caries risk Filipino children by two dentists and two trained health-care workers. Only hand instruments and an encapsulated amalgam, mixed with a manually powered amalgamator, were used. The restorations were evaluated after a service time of 1 to 5 years using modified atraumatic restorative treatment (ART) criteria. Results The overall success rate of the amalgam restorations was 95.3 % (n=1260) after a mean service time of 2.7 years (SD=1.4). Multiple-surface restorations showed significantly higher failure rates (11.4 %) than single-surface occlusal (4.7 %) and single-surface non-occlusal (2.1 %) restorations; 93.6 % of large restorations was performed successfully, but had a risk of failure twice to that of small restorations (odds I. M. Schüler (*) : R. Heinrich-Weltzien Department of Preventive Dentistry and Paediatric Dentistry, Jena University Hospital, Bachstr. 18, 07743 Jena, Germany e-mail: [email protected] B. Monse Department of Education, Health and Nutrition Center, Cagayan de Oro, Philippines C. J. Holmgren Aide Odontologique Internationale, Paris, France T. Lehmann Institute of Medical Statistics, Computer Science and Documentation, Jena University Hospital, Jena, Germany G. S. Itchon Department of Preventive and Community Medicine, School of Medicine, Xavier University, Cagayan de Oro City, Philippines
ratio (OR)=2.141). The score of the decayed, missing, and filled teeth (DMFT) index had significant influence on the success rate. The risk of restoration failure increased by 11.5 % for each unit increase in DMFT (OR=1.148). Neither the operator nor age nor gender of the patient had a significant effect on the success rate of the restorations. Conclusion Amalgam was performed satisfactorily as a filling material when placed under field conditions in manually prepared cavities in the permanent dentition of high cariesrisk children. Success of the restorations was influenced by the patient’s caries experience (DMFT), restoration size, and service time. Clinical relevance Manual restorative treatment (MRT) amalgam restorations were performed satisfactorily, but higher dental caries experience and large cavities contribute to lower success rates. Keywords Amalgam restorations . Success rate . Caries experience . ART
Introduction While in high-income countries affordable and high-quality oral health care is broadly available, more than 70 % of the world’s population, mainly those living in low- and middleincome countries, have little or no access to oral health care [1]. The Philippines National Oral Health Survey (NOHS) conducted in 2006 showed that children attending public elementary schools had received little or no oral care [2]. Caries prevalence was 97.1 % in 6-year olds and 78.4 % in 12-year olds. In 6-year olds, the mean decayed, missing, and filled teeth (DMFT) score was 8.4, while the mean DMFT score in 12-year olds was 2.9. No restored teeth were found in the 4052 children participating in the survey [2]. The limited public financial resources are mainly spent on other urgent
Clin Oral Invest
health problems and not on oral care. An effective but lowcost oral care approach is therefore required due to the high treatment need, the limited financial resources and the shortage of care providers in rural areas. One approach which has been proposed is atraumatic restorative treatment (ART), which is a largely pain-free, minimal intervention approach for treating decayed teeth, particularly in regions where dentists and sophisticated dental equipment are neither available nor affordable [3]. ART involves caries removal and cavity preparation using hand instruments only and filling the cavity with an adhesive filling material [4, 5]. The use of high viscosity glass ionomer cement (GIC) is usually recommended as the filling material for use under field conditions [4–7], mostly due to its ability to adhere to dental hard tissue and its caries protective properties from fluoride release. ART, as a component of the Basic Package of Oral Care, is considered to be an important cornerstone of basic oral care in low-cost settings [7]. Several studies have confirmed the effectiveness of this treatment approach with high survival rates for single-surface restorations. A meta-analysis reported a weighted mean survival rate of single-surface ART restorations in permanent molars of 96 % after 1 year, 85 % after 3 years, and 72 % after 6 years [8]. Multiple surface restorations had lower survival rates [8]. One long-term study has reported success rates for ART restorations of 49.0 % after 10 years [9]. Even if the use of specially developed highviscosity GIC for the ART approach with improved physical properties has led to relatively high success rates for GIC restorations, the wear resistance and strength is lower compared with amalgam restorations [10]. A systematic review [11] concluded that, in comparison with conventional amalgam restorations of the same size, type of dentition, and follow-up period, ART restorations with high-viscosity GIC appear to be equally successful. While amalgam has the potential of being long lasting [12, 13], inexpensive [14], and easy to place [15], its use is usually limited to the dental clinic setting. A possible alternative to ART for outreach situations is “manual restorative treatment—MRT” where amalgam is used as a filling material instead of GIC in cavities prepared manually with hand instruments alone [16]. The term manual restorative treatment—MRT is used to highlight the specifics of this treatment approach, namely the exclusive use of hand instruments for cavity preparation, and because the approach does not meet the definition of ART where an adhesive restorative material is used and where adjacent pits and fissures are sealed [17]. Thus far, only two studies have reported on the applicability and effectiveness of amalgam restorations placed in manually prepared cavities [16, 18, 19]. The objective of the present study was to evaluate the clinical success of amalgam restorations placed over a period of up to 5 years using the MRT approach in permanent teeth of high caries-risk Filipino school children. In addition, the study
sought to determine whether the success rate of MRT restorations is independent of the patient’s caries experience (DMFT), the cavity size, the number of restored surfaces, and the service time.
Materials and methods Nineteen elementary schools were selected in the rural areas of Misamis Oriental, Mindanao, the Philippines, by the Department of Education with regards of accessibility. These were included in a comprehensive oral health program supported by the German non-governmental organization “German Doctors” which started in 1998. Ethical approval was obtained from the Ethics Committee of Xavier University, Cagayan de Oro, Philippines (PHREB 1026), and the study registered at the German Registry of Clinical Trials (DRKS 00005955). Only children whose parents had signed an informed consent were included in the program. As the oral health status of the children was very poor, the preventive program focused on primary prevention (daily tooth brushing with fluoride toothpaste, quarterly application of fluoride varnish, health promotion to the children, parents and teachers) as well as providing tertiary preventive measures (restorative treatment and extraction of non-restorable teeth). During the 5-year oral health-care program, the dental team visited the selected schools on a quarterly basis and performed restorations, extractions, and health promotion activities. Before treatment, the children were clinically examined for dentition status according to the WHO standard for oral health surveys [20]. All cavitated lesions in permanent teeth without obvious clinical pulp involvement were considered restorable, and all children with restorable caries lesions in permanent teeth received MRT restorative treatment. No attempt at randomization was undertaken either for the children or the teeth receiving restorative care. Restorative treatment procedure MRT restorative treatment was provided by two dentists and three health-care workers, working under the direct supervision of the dentists, trained both theoretically and practically in the MRT technique. One assistant was assigned to two operators. The children were treated outdoors in the schoolyard, lying in a supine position on school benches with the operator seated at the 12 o’clock position. No electricity was available. Cotton rolls and cotton pellets were used for moisture control. Access into the caries cavity was achieved using hatchets. The soft carious dentine was removed with excavators (591/1 and 591/3, Hawe Neos, Switzerland). Special attention was given to remove the soft infected dentine as completely as possible and to ensure the presence of undercuts
Clin Oral Invest
in the cavities in order to enable macro-mechanical retention of the filling material. Since in most cases the dentine lesions extended under the enamel and not all undermined enamel was removed during excavation, the nature of the caries lesion, when fully excavated, provided natural macromechanical retention. Conventional visual, tactile, and auditive criteria were used to guide caries excavation until hard dentine, be it stained or unstained, had been reached and the soft infected dentine had been removed. The cavity floor was lined with zinc phosphate cement for pulpal protection since it was found to be the most easy to handle, most reliable, and inexpensive material for use under field conditions. No anesthetics were administered. Encapsulated non-gamma-2 amalgam (Amalcap®, Ivoclar Vivadent AG, Liechtenstein) was mixed with a manually driven amalgamator [16]. Small increments of amalgam were placed into the cavities with an amalgam carrier and condensed with pluggers. Excess material was removed with carvers. For class II restorations, a matrix band and holder (Ivory No 8, Meba, Germany) fixed with wooden wedges was used. All instruments were cleaned with water and soap and sterilized in a pressure cooker. The amalgam residues were collected in a sealed box, transported to Germany, and disposed of according to standard hygiene regulations. Data collection and assessment At the end of the 5-year oral health-care program, the status of the restorations was examined by two experienced and calibrated dentists (B.M., R.H.-W.). One of the evaluators (B.M.) being involved in the provision of the restorations was not independent. All examinations were carried out outdoors in a half-shaded location, using sunlight as the light source. The dentition status of the children was assessed according to WHO standards [18] after tooth brushing. The MRT restorations were evaluated using criteria that had been used in previous ART studies [21–24] (Table 1). Restorations scored Table 1
Quality criteria used for evaluation
Code
Criteria
0 1
Present, satisfactory Present, slight defect at the margin and/or wear of the surface of less than 0.5 mm deep; no repair needed Present, defect at the margin and/or wear of the surface of 0.5 mm or more Present, fracture in restoration Present, fracture in tooth Restoration not present, most or all of restoration missing Restoration not present, other restorative treatment performed Tooth is not present, extraction for whatever reason Unable to diagnose
2 3 4 5 6 7 9
with codes 0 or 1 were assessed as successful, those with code 2–7 were considered failures, and those with code 9 were excluded from further analysis. The location and size of the restorations were registered according to Holmgren et al. [23]. Restorations were classified as “small,” if less than half of the surface either in mesiodistal or buccolingual direction was involved. Restorations exceeding these limits in any direction were classified as “large.” After clinical training and calibration under field conditions, Cohen’s kappa was calculated for the intra- and inter-examiner reliability. Repeat examination of every 15th child was performed. The intra-examiner reliability tested according to MRT restoration evaluation criteria was 0.87 (B. M.) and 0.85 (R. H-W.), while inter-examiner reliability was 0.86. Statistical data analysis The collected data were processed with MS Excel® and analyzed with SPSS 20 for Windows®. Descriptive statistics of the data were expressed as means±standard deviation or frequencies according to the measurement scale. Since multiple restorations were placed in most children, the correlation of the outcome restoration success has to be taken into account. Hence, a generalized estimating equations (GEE) model was fitted to estimate the effect of DMFT and other related factors (gender, age, restoration size, restored surfaces, and operators) on MRT restoration success [25]. In this approach, observations on the same child are modelled as dependent by a first-order autoregressive correlation structure. Odds ratios (OR) derived from the GEE model are provided to show the effect size of the different independent variables on the binary outcome (failure yes/no). In all analyses, the significance level was set at α≤0.05.
Results At the end of the 5-year comprehensive oral health-care program, a total of 1322 MRT restorations, placed in the permanent dentition of 619 school children aged 5 to 15 years old (mean age 8.5±1.6 years), were evaluated. The service time of the restorations was up to 5 years, with a mean service time of 2.7 years (±1.4). The overall success rate of all restorations was 95.3 % (n=1260) (Table 2). No codes 6 and 7 (restoration not present, other restorative treatment performed; tooth not present, extraction for whatever reason) were scored. Restoration-related factors At the final evaluation, the MRT restorations had a service time between less than 1 and 5 years. The success rate varied between 92.7 % after 4 years and 98.8 % after less than 1 year
87.0 (1150) 8.3 (110) 95.3 (1260) 4.0 (53) 0.3 (4) 0.2 (3) 0.2 (2) 4.7 (62) 100 (1322) 87.2 (715) 8.4 (69) 95.6 (784) 3.4 (28) 0.5 (4) 0.2 (2) 0.2 (2) 4.4 (36) 100 (820) 86.7 (435) 8.2 (41) 94.8 (476) 5.0 (25) 0.0 (0) 0.2 (1) 0.0 (0) 5.2 (26) 100 (502) 80.2 (89) 13.5 (15) 93.7 (104) 6.3 (7) 0.0 (0) 0.0 (0) 0.0 (0) 6.3 (7) 100 (111) 91.0 (183) 5.0 (10) 96.0 (193) 3.5 (7) 0.5 (1) 0.0 (0) 0.0 (0) 4.0 (8) 100 (201) 95.3 (81) 3.5 (3) 98.8 (84) 0.0 (0) 0.0 (0) 0.0 (0) 1.2 (1) 1.2 (1) 100 (85)
92.2 (259) 5.0 (14) 97.2 (273) 2.5 (7) 0.4 (1) 0.0 (0) 0.0 (0) 2.8 (8) 100 (281)
88.7 (268) 7.0 (21) 95.7 (289) 3.3 (10) 0.0 (0) 0.7 (2) 0.3 (1) 4.3 (13) 100 (302)
78.9 (270) 13.7 (47) 92.7 (317) 6.4 (22) 0.6 (2) 0.3 (1) 0.0 (0) 7.3 (25) 100 (342)
Health worker, % (n) Dentist, % (n) 5 years, % (n) 4 years, % (n) 3 years, % (n) 2 years, % (n) 1 year, % (n) 3.4 DMFT. The GEE model revealed that the DMFT has a high influence on the success rate. For each unit increase in DMFT, the risk of failure increased by 11.5 % (OR=1.148; p=0.005). Children with higher caries experience more frequently received large (OR=1.070, p=0.009) and multiple-surface (OR=1.163, p
ORIGINAL ARTICLE
Success rates of manual restorative treatment (MRT) with amalgam in permanent teeth in high caries-risk Filipino children I. M. Schüler & B. Monse & C. J. Holmgren & T. Lehmann & G. S. Itchon & R. Heinrich-Weltzien
Received: 28 December 2013 / Accepted: 20 November 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Objectives The objective of the study is to evaluate the success rate of amalgam restorations in manually prepared cavities under field conditions within a comprehensive schoolbased oral health-care program in high caries-risk children. Materials and methods A total of 1322 restorations were placed in the permanent teeth of 619 high caries risk Filipino children by two dentists and two trained health-care workers. Only hand instruments and an encapsulated amalgam, mixed with a manually powered amalgamator, were used. The restorations were evaluated after a service time of 1 to 5 years using modified atraumatic restorative treatment (ART) criteria. Results The overall success rate of the amalgam restorations was 95.3 % (n=1260) after a mean service time of 2.7 years (SD=1.4). Multiple-surface restorations showed significantly higher failure rates (11.4 %) than single-surface occlusal (4.7 %) and single-surface non-occlusal (2.1 %) restorations; 93.6 % of large restorations was performed successfully, but had a risk of failure twice to that of small restorations (odds I. M. Schüler (*) : R. Heinrich-Weltzien Department of Preventive Dentistry and Paediatric Dentistry, Jena University Hospital, Bachstr. 18, 07743 Jena, Germany e-mail: [email protected] B. Monse Department of Education, Health and Nutrition Center, Cagayan de Oro, Philippines C. J. Holmgren Aide Odontologique Internationale, Paris, France T. Lehmann Institute of Medical Statistics, Computer Science and Documentation, Jena University Hospital, Jena, Germany G. S. Itchon Department of Preventive and Community Medicine, School of Medicine, Xavier University, Cagayan de Oro City, Philippines
ratio (OR)=2.141). The score of the decayed, missing, and filled teeth (DMFT) index had significant influence on the success rate. The risk of restoration failure increased by 11.5 % for each unit increase in DMFT (OR=1.148). Neither the operator nor age nor gender of the patient had a significant effect on the success rate of the restorations. Conclusion Amalgam was performed satisfactorily as a filling material when placed under field conditions in manually prepared cavities in the permanent dentition of high cariesrisk children. Success of the restorations was influenced by the patient’s caries experience (DMFT), restoration size, and service time. Clinical relevance Manual restorative treatment (MRT) amalgam restorations were performed satisfactorily, but higher dental caries experience and large cavities contribute to lower success rates. Keywords Amalgam restorations . Success rate . Caries experience . ART
Introduction While in high-income countries affordable and high-quality oral health care is broadly available, more than 70 % of the world’s population, mainly those living in low- and middleincome countries, have little or no access to oral health care [1]. The Philippines National Oral Health Survey (NOHS) conducted in 2006 showed that children attending public elementary schools had received little or no oral care [2]. Caries prevalence was 97.1 % in 6-year olds and 78.4 % in 12-year olds. In 6-year olds, the mean decayed, missing, and filled teeth (DMFT) score was 8.4, while the mean DMFT score in 12-year olds was 2.9. No restored teeth were found in the 4052 children participating in the survey [2]. The limited public financial resources are mainly spent on other urgent
Clin Oral Invest
health problems and not on oral care. An effective but lowcost oral care approach is therefore required due to the high treatment need, the limited financial resources and the shortage of care providers in rural areas. One approach which has been proposed is atraumatic restorative treatment (ART), which is a largely pain-free, minimal intervention approach for treating decayed teeth, particularly in regions where dentists and sophisticated dental equipment are neither available nor affordable [3]. ART involves caries removal and cavity preparation using hand instruments only and filling the cavity with an adhesive filling material [4, 5]. The use of high viscosity glass ionomer cement (GIC) is usually recommended as the filling material for use under field conditions [4–7], mostly due to its ability to adhere to dental hard tissue and its caries protective properties from fluoride release. ART, as a component of the Basic Package of Oral Care, is considered to be an important cornerstone of basic oral care in low-cost settings [7]. Several studies have confirmed the effectiveness of this treatment approach with high survival rates for single-surface restorations. A meta-analysis reported a weighted mean survival rate of single-surface ART restorations in permanent molars of 96 % after 1 year, 85 % after 3 years, and 72 % after 6 years [8]. Multiple surface restorations had lower survival rates [8]. One long-term study has reported success rates for ART restorations of 49.0 % after 10 years [9]. Even if the use of specially developed highviscosity GIC for the ART approach with improved physical properties has led to relatively high success rates for GIC restorations, the wear resistance and strength is lower compared with amalgam restorations [10]. A systematic review [11] concluded that, in comparison with conventional amalgam restorations of the same size, type of dentition, and follow-up period, ART restorations with high-viscosity GIC appear to be equally successful. While amalgam has the potential of being long lasting [12, 13], inexpensive [14], and easy to place [15], its use is usually limited to the dental clinic setting. A possible alternative to ART for outreach situations is “manual restorative treatment—MRT” where amalgam is used as a filling material instead of GIC in cavities prepared manually with hand instruments alone [16]. The term manual restorative treatment—MRT is used to highlight the specifics of this treatment approach, namely the exclusive use of hand instruments for cavity preparation, and because the approach does not meet the definition of ART where an adhesive restorative material is used and where adjacent pits and fissures are sealed [17]. Thus far, only two studies have reported on the applicability and effectiveness of amalgam restorations placed in manually prepared cavities [16, 18, 19]. The objective of the present study was to evaluate the clinical success of amalgam restorations placed over a period of up to 5 years using the MRT approach in permanent teeth of high caries-risk Filipino school children. In addition, the study
sought to determine whether the success rate of MRT restorations is independent of the patient’s caries experience (DMFT), the cavity size, the number of restored surfaces, and the service time.
Materials and methods Nineteen elementary schools were selected in the rural areas of Misamis Oriental, Mindanao, the Philippines, by the Department of Education with regards of accessibility. These were included in a comprehensive oral health program supported by the German non-governmental organization “German Doctors” which started in 1998. Ethical approval was obtained from the Ethics Committee of Xavier University, Cagayan de Oro, Philippines (PHREB 1026), and the study registered at the German Registry of Clinical Trials (DRKS 00005955). Only children whose parents had signed an informed consent were included in the program. As the oral health status of the children was very poor, the preventive program focused on primary prevention (daily tooth brushing with fluoride toothpaste, quarterly application of fluoride varnish, health promotion to the children, parents and teachers) as well as providing tertiary preventive measures (restorative treatment and extraction of non-restorable teeth). During the 5-year oral health-care program, the dental team visited the selected schools on a quarterly basis and performed restorations, extractions, and health promotion activities. Before treatment, the children were clinically examined for dentition status according to the WHO standard for oral health surveys [20]. All cavitated lesions in permanent teeth without obvious clinical pulp involvement were considered restorable, and all children with restorable caries lesions in permanent teeth received MRT restorative treatment. No attempt at randomization was undertaken either for the children or the teeth receiving restorative care. Restorative treatment procedure MRT restorative treatment was provided by two dentists and three health-care workers, working under the direct supervision of the dentists, trained both theoretically and practically in the MRT technique. One assistant was assigned to two operators. The children were treated outdoors in the schoolyard, lying in a supine position on school benches with the operator seated at the 12 o’clock position. No electricity was available. Cotton rolls and cotton pellets were used for moisture control. Access into the caries cavity was achieved using hatchets. The soft carious dentine was removed with excavators (591/1 and 591/3, Hawe Neos, Switzerland). Special attention was given to remove the soft infected dentine as completely as possible and to ensure the presence of undercuts
Clin Oral Invest
in the cavities in order to enable macro-mechanical retention of the filling material. Since in most cases the dentine lesions extended under the enamel and not all undermined enamel was removed during excavation, the nature of the caries lesion, when fully excavated, provided natural macromechanical retention. Conventional visual, tactile, and auditive criteria were used to guide caries excavation until hard dentine, be it stained or unstained, had been reached and the soft infected dentine had been removed. The cavity floor was lined with zinc phosphate cement for pulpal protection since it was found to be the most easy to handle, most reliable, and inexpensive material for use under field conditions. No anesthetics were administered. Encapsulated non-gamma-2 amalgam (Amalcap®, Ivoclar Vivadent AG, Liechtenstein) was mixed with a manually driven amalgamator [16]. Small increments of amalgam were placed into the cavities with an amalgam carrier and condensed with pluggers. Excess material was removed with carvers. For class II restorations, a matrix band and holder (Ivory No 8, Meba, Germany) fixed with wooden wedges was used. All instruments were cleaned with water and soap and sterilized in a pressure cooker. The amalgam residues were collected in a sealed box, transported to Germany, and disposed of according to standard hygiene regulations. Data collection and assessment At the end of the 5-year oral health-care program, the status of the restorations was examined by two experienced and calibrated dentists (B.M., R.H.-W.). One of the evaluators (B.M.) being involved in the provision of the restorations was not independent. All examinations were carried out outdoors in a half-shaded location, using sunlight as the light source. The dentition status of the children was assessed according to WHO standards [18] after tooth brushing. The MRT restorations were evaluated using criteria that had been used in previous ART studies [21–24] (Table 1). Restorations scored Table 1
Quality criteria used for evaluation
Code
Criteria
0 1
Present, satisfactory Present, slight defect at the margin and/or wear of the surface of less than 0.5 mm deep; no repair needed Present, defect at the margin and/or wear of the surface of 0.5 mm or more Present, fracture in restoration Present, fracture in tooth Restoration not present, most or all of restoration missing Restoration not present, other restorative treatment performed Tooth is not present, extraction for whatever reason Unable to diagnose
2 3 4 5 6 7 9
with codes 0 or 1 were assessed as successful, those with code 2–7 were considered failures, and those with code 9 were excluded from further analysis. The location and size of the restorations were registered according to Holmgren et al. [23]. Restorations were classified as “small,” if less than half of the surface either in mesiodistal or buccolingual direction was involved. Restorations exceeding these limits in any direction were classified as “large.” After clinical training and calibration under field conditions, Cohen’s kappa was calculated for the intra- and inter-examiner reliability. Repeat examination of every 15th child was performed. The intra-examiner reliability tested according to MRT restoration evaluation criteria was 0.87 (B. M.) and 0.85 (R. H-W.), while inter-examiner reliability was 0.86. Statistical data analysis The collected data were processed with MS Excel® and analyzed with SPSS 20 for Windows®. Descriptive statistics of the data were expressed as means±standard deviation or frequencies according to the measurement scale. Since multiple restorations were placed in most children, the correlation of the outcome restoration success has to be taken into account. Hence, a generalized estimating equations (GEE) model was fitted to estimate the effect of DMFT and other related factors (gender, age, restoration size, restored surfaces, and operators) on MRT restoration success [25]. In this approach, observations on the same child are modelled as dependent by a first-order autoregressive correlation structure. Odds ratios (OR) derived from the GEE model are provided to show the effect size of the different independent variables on the binary outcome (failure yes/no). In all analyses, the significance level was set at α≤0.05.
Results At the end of the 5-year comprehensive oral health-care program, a total of 1322 MRT restorations, placed in the permanent dentition of 619 school children aged 5 to 15 years old (mean age 8.5±1.6 years), were evaluated. The service time of the restorations was up to 5 years, with a mean service time of 2.7 years (±1.4). The overall success rate of all restorations was 95.3 % (n=1260) (Table 2). No codes 6 and 7 (restoration not present, other restorative treatment performed; tooth not present, extraction for whatever reason) were scored. Restoration-related factors At the final evaluation, the MRT restorations had a service time between less than 1 and 5 years. The success rate varied between 92.7 % after 4 years and 98.8 % after less than 1 year
87.0 (1150) 8.3 (110) 95.3 (1260) 4.0 (53) 0.3 (4) 0.2 (3) 0.2 (2) 4.7 (62) 100 (1322) 87.2 (715) 8.4 (69) 95.6 (784) 3.4 (28) 0.5 (4) 0.2 (2) 0.2 (2) 4.4 (36) 100 (820) 86.7 (435) 8.2 (41) 94.8 (476) 5.0 (25) 0.0 (0) 0.2 (1) 0.0 (0) 5.2 (26) 100 (502) 80.2 (89) 13.5 (15) 93.7 (104) 6.3 (7) 0.0 (0) 0.0 (0) 0.0 (0) 6.3 (7) 100 (111) 91.0 (183) 5.0 (10) 96.0 (193) 3.5 (7) 0.5 (1) 0.0 (0) 0.0 (0) 4.0 (8) 100 (201) 95.3 (81) 3.5 (3) 98.8 (84) 0.0 (0) 0.0 (0) 0.0 (0) 1.2 (1) 1.2 (1) 100 (85)
92.2 (259) 5.0 (14) 97.2 (273) 2.5 (7) 0.4 (1) 0.0 (0) 0.0 (0) 2.8 (8) 100 (281)
88.7 (268) 7.0 (21) 95.7 (289) 3.3 (10) 0.0 (0) 0.7 (2) 0.3 (1) 4.3 (13) 100 (302)
78.9 (270) 13.7 (47) 92.7 (317) 6.4 (22) 0.6 (2) 0.3 (1) 0.0 (0) 7.3 (25) 100 (342)
Health worker, % (n) Dentist, % (n) 5 years, % (n) 4 years, % (n) 3 years, % (n) 2 years, % (n) 1 year, % (n) 3.4 DMFT. The GEE model revealed that the DMFT has a high influence on the success rate. For each unit increase in DMFT, the risk of failure increased by 11.5 % (OR=1.148; p=0.005). Children with higher caries experience more frequently received large (OR=1.070, p=0.009) and multiple-surface (OR=1.163, p
