Assessment of manual restorative treatment (MRT) with amalgam in high-caries Filipino children: results after 2 years

Transcription

1 Community Dent Oral Epidemiol 23; 31: 129±35 Printed in Denmark. All rights reserved Assessment of manual restorative treatment (MRT) with amalgam in high-caries Filipino children: results after 2 years B. Monse-Schneider 1,2, R. Heinrich- Weltzien 3, D. Schug 1, A. Sheiham 2 and A. Borutta 3 1 Committee of German Doctors, Elsheimerstr. 9, D-622 Frankfurt/Main, Germany, 2 Department of Epidemiology and Public Health, University College London, Gower Street Campus, 1±19Torrington Place, London WC1E 6BT, UK, 3 Friedrich-Schiller-University of Jena, WHO Collaborating Center `Prevention of Oral Diseases', Nordhaeuser Str. 78, D-9989 Erfurt, Germany Monse-Schneider B, Heinrich-Weltzien R, Schug D, Sheiham A, Borutta A. Assessment of Manual restorative treatment (MRT) with amalgam in high-caries Filipino children: results after 2 years. Community Dent Oral Epidemiol 23; 31: 129±35. ß Blackwell Munksgaard, 23 Abstract ± Background: The atraumatic restorative treatment (ART), using only hand instruments and glass-ionomer cement as adhesive material is recommended for restorative dental treatment in disadvantaged communities lacking electricity and sophisticated dental equipment. Research is required on more durable restorative materials appropriate for populations with high-caries experience. Objectives: The aim of the study was to evaluate, under eld conditions, the applicability and effectiveness of an encapsulated amalgam as restorative material in ART prepared cavities in permanent teeth of children with high-caries rates. As the de nition of ART restricts the manual treatment to adhesive materials the approach used is called the manual restorative treatment (MRT). Methods: Two dentists and two trained healthcare workers, using hand instruments and an encapsulated amalgam that was mixed with a manually driven triturator, placed a total of 934 restorations in the permanent dentition in 466 children. Due to irregular school attendance of Filipino children only 611 restorations could be evaluated by one independent dentist. The average age at reassessment of restorations was months. Results: 93.3% of the restorations were acceptable. The failure rate of occlusal surface restorations was 5.6% compared with 13.6% of buccal surface llings. The survival rate of large occlusal restorations was 95.1% compared with 93.7% for small restorations. The survival of MRT restorations was not in uenced by the experience and professional level of the operator. Conclusions: Amalgam is a suitable MRT material, especially for extensive occlusal lesions in high-caries populations. Studies of longer duration are needed to con rm this nding. Key words: amalgam; ART restorations; deprived communities; dental caries; MRT Dr B. Monse-Schneider, HoÈlterweg 2, Ladbergen, Germany Tel: Fax: bella.monse-schneider@t-online.de Submitted 2 February 22; accepted 6 August 22 In the Philippines, the limited nancial public resources are mostly spent on urgent medical and social problems. As caries and periodontal diseases are not regarded as life-threatening, prevention and treatment of dental diseases have a low priority. There is no comprehensive public oral health service and most private dentists work in cities. The national dental survey conducted in 1998 reported that 94% of 5-year-old Filipino children had caries and in 12-year-old children the mean DMFT was 4.6. Ninety percent of the decay was untreated (1). This situation is particularly alarming and suggests the need for comprehensive approaches focusing on preventive and restorative measures. In the province of Misamis Oriental on the second largest Philippine island Mindanao; ve school dentists are responsible for treating 11 children in elementary schools. Only very limited funds are available for dental care. The high need for treatment, the lack of nancial resources and the shortage of treatment providers requires a low cost `appropriate technology' approach for dental care in such populations. The atraumatic restorative treatment (ART) has been recommended for disadvantaged 129

2 Monse-Schneider et al. communities lacking regular electricity and sophisticated dental equipment (2). The use of glass-ionomer cement (GIC) is universally recommended for the ART approach under eld conditions (3±5). GIC is mostly used because of its ability to adhere to dental hard tissue and its caries protective properties through the release of uoride. Although cariogenic and cariostatic properties are suggested, in vivo and in situ studies have not yet demonstrated the effect on carious dentine (6). A systematic review of 52 clinical studies did not reveal any conclusive evidence about the caries inhibitory effect of GIC (7). In addition, due to their relatively poor physical properties, GICs show more wear in stress bearing occlusal cavities (8). After a study on survival rates of small and large restorations, it was recommended to ensure excellent success rates, that the use of GIC should be ideally restricted to relatively small cavities surrounded by suf cient sound tooth structure (9). Other controlled clinical studies suggested that in permanent teeth, GIC should only be used for temporary restorations because of its inadequate strength (1). Due to the uncertainties about the longevity of GIC inlargecavitiesandthelackofevidenceofitseffectiveness for high-caries populations, a restorative material such as amalgam (11, 12), that has a potential of being more long-lasting, inexpensive, easy to use by dental auxiliaries and technique tolerant may be more appropriate in some circumstances. Since ART was predominantly used successfully in populations with low-caries experience the application of the technique should be modi ed for highrisk patients with rampant caries, before the bene t of the treatment can be ascertained (11, 13). It is evident that research is needed on a variation of the ART, using more durable materials in high-risk patients with large carious lesions. It was, therefore, decided to test whether amalgam was a suitable restorative material when used in a purely manual restorative treatment approach in a high-caries population. While ART is de ned by Frencken & Holmgren (3) as a procedure based on removing carious tissues using hand instruments alone and restoring the cavity with an adhesive material, amalgam fails to meet this de nition relating to adhesion. In order to avoid confusion it was considered advisable to use a term that highlights the speci cs of this treatment approach, namely the absence of rotary instruments and the use of hand instruments. This approach was, therefore, called `Manual restorative treatment' (MRT). The objective of the present study was to evaluate, under eld conditions, the applicability and effectiveness in terms of survival of an encapsulated amalgam as restorative material for MRT prepared cavities of different sizes in permanent teeth of children with high-caries rates. Materials and methods In 1998, the Philippine Department of Education, Culture and Sports selected 19elementary schools located in rural areas of the province of Misamis Oriental, Mindanao, Philippines, to participate in an oral health preventive program in co-operation with a German nongovernmental organization. Before the start of the preventive program, a total of 1574 rst graders with a mean age of 7.98 years were clinically examined according to the WHO standard for oral health surveys (14). They had a dmft of 7.2 (SD ˆ 5.1) and DMFT of 1.2 (SD ˆ 1.4). There were no lled teeth. Only 9% of the children were cavity-free in both dentitions, while 44% of the children were cavity-free in the permanent dentition. Because of the poor oral health status of the Filipino children, the preventive program focused on primary (daily tooth brushing, application of a uoride varnish, dietary counseling) as well as tertiary (restorative treatment, extraction of nonrestorable deciduous and permanent teeth) preventive measures. The parents of the children were informed about the program and gave written informed consent. Between October 1998 and August 1999 a total of 934 MRT llings were placed in 466 unselected children with a mean age of 7.2 years (SD ˆ 1.). A caries level of 8.9dmft (SD ˆ 4.8) and 2.2 DMFT (SD ˆ 1.2) was recorded in the children who needed restorative treatment and/or extractions in the permanent dentition. The restorative treatment was performed by two dentists and two trained healthcare workers using the treatment approach as described in the ART manual (15). The children were treated outdoors in the schoolyard, lying in a supine position on benches available in the schools. As no electricity was available, a dry working area was achieved using cotton rolls and cotton pellets for moisture control. The entrance to the cavity was prepared by using hatchets. The soft carious dentine was removed with excavators (591/1, 591/3, Hawe Neos, Switzerland). The MRT approach used here is based on the restorative principle of removing caries as completely as possible from the cavity oor using conventional tactile and visual 13

3 MRT amalgam restorations in high-caries Filipino children criteria (16). No soft dentine was left on the cavity oor. According to Kidd et al. (17) the scraping sound of the excavator on the hard unstained or stained dentin indicates that the infected dentine is adequately excavated. The hard cavity oor was covered with a zinc phosphate base since it is the most easy to handle, most reliable and inexpensive material for use under eld conditions. Encapsulated nongamma-2 amalgam (Amalcap, Ivoclar Vivadent AG, Liechtenstein) was mixed with a manually driven triturator (Fig. 1) and placed in the cavity using an amalgam gun. Amalgam was condensed with pluggers. Small increments of the material were placed in the cavity until it was slightly over lled to ensure ef cient condensation. The over lled material was removed with carvers. Given the lack of adhesiveness of amalgam, special attention was given to preparing undercuts in the cavities to enable macro-mechanical retention. This, and the use of amalgam were the only modi cations made to the ART technique. Matrix strips and wedges were used for Class II restorations. The four operators carried out the treatment with a chairside assistant. In general, one assistant was assigned to two operators. All but nine children were treated without administering local anesthesia. At the evaluation, the MRT restorations had been in place for at least 2 years with an average age of months. An independent external experienced examiner (R.H.-W.) who was not involved in the treatment of the children carried out the evaluation of the restorations. WHO periodontal probes, plane mirrors and cottonwool rolls for drying were used for the examination. All examinations were carried out in half-shade under trees, using sunlight as the light source. The criteria used for the evaluation of the MRT restorations (Table 1) were Table 1. Criteria used for evaluation of ART restorations Codes Criteria Present, satisfactory 1 Present, slight defect at the margin and/or wear of the surface of less than.5 mm deep; a no repair needed 2 Present, defect at the margin and/or wear of the surface of.5 mm or more 3 Present, fracture in restoration 4 Present, fracture in tooth 5 N/A (not applicable) 6 Restoration not present, most or all of restoration missing 7 Restoration not present, other restorative treatment performed 8 Tooth is not present, extraction for whatever reason 9Unable to diagnose a Assessed with.5 mm ball-tip of WHO CPI periodontal probe. similar to those of previous ART studies (2, 9, 18, 19). Restorations with code and 1 were regarded as successful, while those with code 2±7 were considered to be failures. Restorations that scored 8 and 9 were excluded from the study altogether. In accordance with Holmgren et al. (9), the location and size of the restoration was registered. Fillings were classi ed as large if a restoration covered more than half the tooth surface either in a mesio-distal or buccolingual direction. Restorations were classi ed as small if less than half of the surface in any direction was involved. Cohen's Kappa calculated for the intraexaminer reliability after repeated examinations of every 15th subject, was.86. The collected data was entered in Microsoft Excel worksheets and analyzed using the SPSS software. For statistical comparisons of differences between the success rates of different types of restorations the contingency table test of independence (chi-square) was used (2). A signi cant difference was a P.5. Fig. 1. Manually driven triturator. Results Six hundred eleven restorations placed in 316 children were evaluated in a school environment after an average service time of months or after at least 24 months following placement. Due to the irregular school attendance of Filipino pupils, the lost-to-follow-up rate was 34.5%. One hundred and fty-one children received one MRT restoration, 15 children two restorations and 6 children three or more restorations. A total of 95.3% of all the restorations were placed in the permanent rst molars 131

4 Monse-Schneider et al. Table 2. Tooth-related distribution of the ART amalgam restorations in Filipino children Tooth groups n % Maxillary Premolars First molars Mandibula Premolars First molars Second molars Total (Table 2). Most of the llings were in the lower rst molars (77.1%). Table 3 shows the distribution of the restorations and the restoration status according to the surfaces. There were 523 occlusal one-surface restorations, 74 nonocclusal one-surface restorations and 14 Class II restorations. Most of the restorations were in an excellent condition (9.8%). Minor defects, which did not need to be repaired, were found in 15 restorations (2.5%). The overall survival rate was 93.3%. Forty-one restorations failed (6.7%), 2.3% because of de ciencies at the restoration margin and 2.1% were lost completely. In 1.6% of the cases, a replacement of MRT amalgam restorations was provided. A total of.6% of the restorations was scored as failures on account of fracture of the tooth (.3%) and restoration (.3%), respectively. The failure rate of occlusal one-surface restorations was 5.6% (29out of 523) compared with 13.6% (1 out of 74) of the nonocclusal Class I restorations and 14.3% (2 out of 14) of Class II restorations. However, signi cant differences were only evident Table 4. Success rates of one-surface ART amalgam restorations in Filipino children after an average service time of 27 months Small occlusal restorations Large occlusal restorations Criteria a n % n % Total a For codes, see Table 1. between occlusal and nonocclusal Class I restorations and between occlusal Class I restorations and ClassIIrestorations,respectively(w 2 ˆ 1.11,Pˆ.4). Most failures in occlusal one-surface restorations were de ciencies at the restoration margin (2.7%), while for nonocclusal one-surface restorations it was loss of the restoration (4.1%) and replacement (9.5%). The survival rates of small and large occlusal onesurface restorations are presented in Table 4. Three hundred and two restorations were de ned as large, while 221 restorations were classi ed as small. The survival rate of large restorations was 95.% compared with 93.7% for small Class I restorations. This difference was not signi cant (w 2 ˆ 1.18, P ˆ.55). Mainly failures of large restoration were due to marginal defects (3%), and for small restorations, loss of the restoration (3.6%). The success rate of restorations was not related to the experience or professional level of the operator (Table 5). Table 3. Quality of ART amalgam restorations in Filipino children after an average service time of 27 months Criteria a Surface Total Class I occlusal n % % of total Class I nonocclusal n % % of total Class II n % % of total Total n % % of total a For codes, see Table

5 MRT amalgam restorations in high-caries Filipino children Table 5. Restoration quality in relation to the professional level of the operator Restoration quality Operator Total Health-worker n % Dentists n % Total n % Discussion ART was developed in response to the treatment need of deprived communities lacking sophisticated dental equipment or even electricity and running water. The possibility of restoring teeth using only simple hand instruments was promoted and widely accepted. The approach was called ART because it does not affect sound tooth structure and is minimally invasive dentistry. The name also implies that the treatment is atraumatic to the patient. As Anusavice (13) pointed out, the access to the cavity, using hatchets to widen the entrance or to fracture overhanging enamel may cause fragmentation of sound or undermined enamel. Therefore, it is not atraumatic. Another reason for questioning the term atraumatic is that the excavation of soft carious dentine using an excavator scraping over the cavity oor, although causing less pain than with rotary instruments (21, 22), is traumatic. Therefore, to point out the typical features and capacities of this appropriate restorative approach, namely the absence of rotary instruments, we suggest using the term `MRT', in this paper to comply with the de nition of the originators of ART. In future, to avoid confusion, we suggest a broadening of the de nition of ART, focusing on the treatment setting regardless of the material used. This study was not designed as a random controlled trial. It was done to assess whether amalgam restorations would be retained successfully in MRT prepared cavities in high-caries risk children. The restorative treatment of children using the MRT approach is a part of the tertiary prevention measures of a comprehensive preventive program for Filipino elementary school pupils. Therefore, neither the children nor the teeth requiring treatment were randomly selected. All the children requiring dental care and all carious lesions received restorative treatment provided the pulp was not involved. The quality of the restorations was examined in the course of an extensive rst evaluation of the effectiveness of the oral health care program initiated 3 years ago. In the present study, 611 of the 934 amalgam llings were evaluated after an average service life of 27 months. The high lost-to-follow-up rate of 34.5% is attributed to the children's irregular attendance at school. Heavy rains, having to help with harvesting and looking after smaller siblings as well as a generally lax attitude towards education in uences the attendance at state elementary schools. The distribution of treated teeth and tooth surfaces of 7-year-old Filipino children re ects the common pattern of caries on occlusal surfaces and buccal pits of the permanent rst molars (23). More than 9% of all lesions were pit and ssure caries on the occlusal surface of rst molars as the surface with the highest caries suspectibility in low- and high-caries risk children. The survival rate of occlusal MRT amalgam llings (94.4%) is similar to the success rate of conventionally placed amalgam llings. Mandari et al. (24) reported a 2-year survival rate of 92% for amalgam restorations. In relation to three different treatment approaches which compared conventional (fully equipped dental unit in a dental of ce), modi ed conventional (portable dental equipment in a eld setting) and modi ed ART approach (ART approach combined with the use of a caries removal solution) no signi cant differences were found. Survival rates varied between 89and 94%. In the present study, the survival rate of buccal llings was substantially lower than that of occlusal llings. Defects of restoration margins (2.7%) and the loss of llings (1.9%) were the main causes of failure in Class I occlusal restorations. The failure rate of Class I nonocclusal restorations were 13.5%. All these cases were mainly very small cavities in which macromechanical retention through the preparation of undercuts could not be achieved with hand instruments. Complete loss of restoration was the result. Lacking the capacity of adhesion amalgam requires a particular cavity design, which is deep enough but 133

6 Monse-Schneider et al. also has undercuts in the walls. Treatment of the walls and overhanging sound enamel will create the necessary undercut. In this connection, the study of Phantumvanit et al. (19) should be considered. The authors found comparable results (17% failure rate) for one-surface ART restorations with GIC after 2 years. However, they reported the opposite results to ours for buccal restorations, namely signi cantly higher survival rates for buccal than for occlusal llings. ART using GIC is not generally recommended for restoration of Class II cavities (3, 9, 25, 26), as GIC does not ful ll the mechanical requirements. In one study, 6 out of 14 (42%) such restorations were defective after 3 years in situ (9). In the present study, 2 out of 14 MRT restorations were defective after 2 years. This low number of cases, however, is inadequate for a reliable evaluation. Nevertheless, the results are more promising than those achieved with GIC. To compare results for small and large llings, the size of the occlusal llings was de ned according to Holmgren et al. (9). In the Filipino children, most of the one-surface occlusal llings were classi ed as large, which indicates the high-carious activity within the study group. The large llings had a slight and insigni cant higher survival rate (95.1%) than the small ones (93.7%). A defective cavity margin (9out of 15 failed restorations) was the main reason of failure in large restorations. Complete loss of the lling was the most common code for failure of small restorations (8 out of 14 failed llings). The loss of lling was most likely caused by inadequate macro mechanical retention as with buccal restorations. Holmgren et al. (9) recorded a survival rate of 96% for small GIC llings and only 83% for large llings after a service life of 2 years. The authors concluded that GIC should ideally be restricted to small llings because of their speci c properties and that GIC is not the material of choice for larger cavities. The high-caries experience in Filipino children, however, required a restorative technique that could also be used to treat larger lesions. If the indication for restorative treatment had been restricted to small lesions, more than half of the teeth that were lled with amalgam in the Filipino children would have had to be extracted. The high-survival rate of large occlusal restorations (95.1%) shows that the MRT approach enables the operator to expand the indication to large caries lesions. A signi cant disadvantage of amalgam is its inadequate sealing capacity. The high-caries activity in Filipino children demands a preventive strategy that includes sealing of the occlusal surfaces of molars. The two types of materials that have been used in the ART/MRT technique to date, GIC and amalgam, possess different properties and have different indications. It could be questioned whether these materials ideally complement each other. While GIC is used for ssure sealing, preventive resin restorations and restoring small cavities, amalgam seems to provide a viable solution for treating small and large cavities using the ART technique. Further research including comparative studies is needed to make more generalizable recommendations. A prerequisite for the use of amalgam under eld conditions should be a procedure, which ensures mercury hygiene requirements and offers a modern nongamma-2 amalgam. The compressive strength of Amalcap achieved with the manual triturator was equivalent to that obtained with an electric mixer (Silamat, Ivoclar Vivadent AG, Liechtenstein). This test was carried out by Ivoclar Vivadent according to ISO 1559(dental materials, alloys for dental amalgam). In a 3-year pilot phase, this mixer has proved to be sturdy, reliable and low in maintenance. A further advantage of MRT/ART is that these manual approaches do not require a local anesthetic as they cause considerably less pain than rotary instruments. In the present study, an anesthetic had only to be used in 9cases. Our study con rms the results of a previous study in which the sensitivity to pain during the excavation of small lesions using hand instruments and rotary instruments was compared. Signi cantly less pain was registered with the manual than with the conventional method using rotary instruments (21). This study presents initial ndings with amalgam ± a material that has been used extensively and successfully for the past 15 years, and a new minimally invasive treatment strategy in a high-caries population. In a MRT approach, amalgam seems to be a viable solution for treating larger cavities where the restorations are likely be subjected to heavy occlusal stresses and abrasive wear. Additionally, in cases of advanced carious lesions the indication for using MRT can be expanded and premature extractions prevented. References 1. Dental Health Service National monitoring and evaluation dental survey. Philippines: Department of Health;

7 MRT amalgam restorations in high-caries Filipino children 2. Frencken JE, Pilot T, Songpaisan Y, Phatumvanit P. Atraumatic restorative treatment (ART). Rationale, technique, and development. J Public Health Dent 1996;56:135±4. 3. Frencken JE, Holmgren C. Atraumatic restorative treatment for dental caries. Nijmegen: STI Book b.v.; Frencken JE, Holmgren C. Painting the future for ART. Community Dent Oral Epidemiol 1999;27:449± Frencken JE, Holmgren C. How effective is ART in the management of dental caries? Community Dent Oral Epidemiol 1999;27:423±3. 6. Weerheijm KL, Groen HJ. The residual caries dilemma. Community Dent Oral Epidemiol 1999;27:436± Randall RC, Wilson NH. Glass ionomer restoratives: a systematic review of a secondary caries treatment effect. J Dent Res 1999;78:628± Smales RJ, Gerke DC, White IL. Clinical evaluation of occlusal glass ionomer, resin and amalgam restorations. J Dent 199;18:243±9. 9. Holmgren C, Lo E, Hu DY, Wan HC. ART restorations and sealants placed in Chinese school children ± results after 3 years. Community Dent Oral Epidemiol 21;28:314±2. 1. Hickel R, Kunzelmann KH. Glasionomer und KompomerfuÈ llungen. In: Heidemann, D, editor. Kariologie und FuÈ llungstherapie, 4th edn. MuÈ nchen, Wien, Baltimore: Urban & Schwarzenberg; p. 156± MjoÈr IA, Gordan VV. A review of the atraumatic restorative treatment (ART). Int Dent J 1999;49:127± Chadwick BL, Dummer PMH, Dunstan FD, et al.what type of filling? Best practice in dental restorations. Qual Health Care 1999;8:22± Anusavice KJ. Does ART have a place in preservative dentistry? Community Dent Oral Epidemiol 1999;27:442± Oral Health Surveys. Basic Methods, 4th edn. Geneva, World Health Organisation Frencken JE, Phatumvanit P, Pilot T, Songpaisan Y, van Amerongen E. Manual for the atraumatic restorative treatment approach to control dental caries, 3rd edn. Groningen: WHO Collaborating Centre for Oral Health Services Research; Kidd EAM, Joyston-Bechal S, Smith MM, Smith SR. The use of caries detector dye in cavity preparation. Br Dent J 1989;167:132± Kidd EAM, Joyston-Bechal S, Beighton D. The use of caries detector dye during cavity preparation: a microbiological assessment. Br Dent J 1993;174:245± Frencken JE, Makoni F, Sithole WD. ART restorations and glass ionomer sealants in Zimbabwe: survival after 3 years. Community Dent Oral Epidemiol 1998;26:372± Phantumvanit P, Songpaisan Y, Pilot T, Frencken JE. Atraumatic restorative treatment (ART): a 3-year community field trial in Thailand ± survival of onesurface restorations in the permanent dentition. J Public Health Dent 1996;56:141±5. 2. Hartung J, Elpelt B, KloÈsener KH. Statistik. Lehr- und Handbuch der Angewandten Statistik, 11th edn MuÈ nchen, Oldenbourg Rahimtoola S, van Amerongen E, Maher R, Groen H. Pain related to different ways of minimal intervention in the treatment of small caries lesions. J Dent Child 2;67:123± van Amerongen WE, Rahimtoola S. Is ART really atraumatic? Community Dent Oral Epidemiol 1999;27:431± Hannigan A, O'Mullane D, Barry D, SchaÈfer F, Roberts AJ. A caries susceptibility classification of tooth surfaces by survival time. Caries Res 2;34:13± Mandari GJ, Truin GJ, van't Hof MA, Frencken JE. Effectiveness of three minimal intervention approaches for managing dental caries: survival of restorations after 2 years. Caries Res 21;35:9± Wilkie R, Lidums A, Smales R. Class II glass ionomer cement tunnel, resin sandwich and amalgam restorations over 2 years. Am J Dent 1993;6:181± Mallow PK, Durward CS, Klaipo M. Restoration of permanent teeth in young rural children using the atraumatic restorative treatment (ART) technique and Fuji II glass ionomer cement. Int Paediat Dent 1998;8:35±4. 135