Clinicians choices of restorative materials for children

Transcription

1 ADRF RESEARCH REPORT Australian Dental Journal 2003;48:(4): Clinicians choices of restorative materials for children LA Tran,* L Brearley Messer* Abstract Background: Recently, there has been an expansion in the range of tooth-coloured restorative materials available. In 1999, the National Health and Medical Research Council recommended clinicians use alternatives to amalgam in children where appropriate. Methods: A three-part 29-item questionnaire was developed, tested in a focus group, and distributed to members of the Australasian Academy of Paediatric Dentistry (AA; paediatric dentists and paediatric dentistry postgraduate students; n=55), and the Australian and New Zealand Society of Paediatric Dentistry, Victorian Branch (SPD; general dentists and dental therapists; n=50). Participant information, material choices, and six hypothetical clinical scenarios were addressed. Results: The overall response rate was 74 per cent. For both groups, the first ranked factor influencing choice of restorative material for vital primary teeth was child age, and caries experience for vital first permanent molars. For moderate-sized Class I and II restorations in primary molars, a tooth-coloured material was chosen by 92 and 84 per cent respondents respectively. For restoring two separate proximal lesions in a primary molar, 65 per cent chose a tooth-coloured material followed by a stainless steel crown (27 per cent; all AA members), then amalgam (8 per cent). The SPD respondents were significantly more likely to choose glass ionomer cement for Class I and II restorations and for restoring two proximal lesions (all p=0.000) in primary molars than AA respondents, who were more likely to choose composite resins/compomers or amalgam/stainless steel crowns for these restorations. Younger respondents (21-40 years) were significantly more likely to choose composite resins/compomers or amalgam/stainless steel crowns (p=0.048) than older respondents (41-65 years), who were likely to choose glass ionomer cement. Conclusions: For Class I and II restorations in primary molars, glass ionomer cement was the material chosen most frequently (SPD respondents); preference for amalgam or stainless steel crowns was low (both SPD and AA groups). The wide range of materials chosen for the hypothetical clinical scenarios suggests the need for guidelines on *Paediatric Dentistry, School of Dental Science, The University of Melbourne, Victoria. selection of restorative materials, and the need for longitudinal studies to follow actual clinical outcomes of the materials chosen. Key words: Primary dentition, tooth-coloured restorative materials, paediatric dentistry. (Accepted for publication 25 May 2003.) INTRODUCTION Recently, there has been an expansion in the range of tooth-coloured materials available for restoring primary and young mixed dentitions. In addition to amalgam and stainless steel crowns, improved conventional glass ionomer cements and composite resins, resin-modified glass ionomer cements and polyacrylic acid modified composites (compomers) have become available. 1-3 Community concerns over amalgam have prompted parental requests for alternative materials. In addition, in 1999 the National Health and Medical Research Council (NHMRC, Australia) recommended clinicians use alternatives to amalgam where appropriate. 4 Adhesive restorative materials have allowed more conservative cavity preparations, leading to minimized designs. To date, there have been no consistent guidelines developed in the paediatric dental literature for either cavity design or material selection, and choice appears based upon clinician preference. Amalgam is still the material of choice for large occlusal restorations and Class II restorations not extending beyond the line angles, which require durability and strength, and where aesthetics is not a concern. 5,6 A recent practice-based study of primary dentitions reported that the median age of amalgam restorations (three years) was significantly higher than that of tooth-coloured materials (two years). 7 Until recently, amalgam was the restorative material used most frequently. 8 Concerns about mercury toxicity, impact on environmental pollution, and aesthetics have decreased the use of amalgam in paediatric dentistry, particularly in European countries where its use is restricted. 9,10 Amalgam use in private practice in Australia has declined from 57.9 per cent of all restorations in , to 27 per cent in In 1999, the NHMRC recommended amalgam should not be placed in, or removed from, the Australian Dental Journal 2003;48:4. 221

2 dentitions of children. 4 However, there is still no clear scientific evidence linking amalgam restorations and systemic diseases or chronic illness. 12,13 Conventional glass ionomer cement is a biocompatible, adhesive, aesthetic and fluorideleaching material with favourable thermal expansion and contraction properties. 1,14 However, it is brittle, radiolucent and susceptible to erosion and wear and such restorations in primary dentitions are significantly more likely to require replacement than amalgam restorations. 2,15,16 Clinical studies indicate conventional glass ionomer cement is not an appropriate alternative to amalgam due to its poor long-term performance in load-bearing restorations, unless the teeth are due to exfoliate within two years. 17,18 The resin-modified glass ionomer cements are glassionomer/resin hybrids which retain an acid-base curing reaction and the advantages of a glass ionomer cement, with command set, handling ease, fracture toughness, and wear resistance. 3,14 Despite disadvantages such as water absorption and radiolucency, recent reports suggest resin-modified glass ionomer cement to be a suitable alternative to amalgam. 3,14,19 One recent clinical study examining three year-old resin-modified glass ionomer cement restorations in primary dentitions suggested that the material is reliable and a proven alternative to amalgam and composite resin for primary teeth. 20 Composite resin is the most aesthetic material, adhesive to tooth structure with good wear properties and command set. In paediatric dentistry, a highly-filled composite resin is recommended for preventive resin restorations, Class I and II restorations not extending beyond the line angles, and anterior restorations. 21 However, composite resin is technique-sensitive, requiring complete moisture control and careful case selection; polymerization shrinkage occurs and secondary caries may be difficult to diagnose. 15,21,22 The mechanical properties of composite resin may be inferior to those of amalgam and the clinical durability appears to be shorter. 7,10,23 Newly introduced, packable composite resin may be easier to manipulate. 24,25 Compomers are recommended for paediatric dentistry as they exhibit properties similar to composite resin and release fluoride (but less than released by glass ionomer cement). 1,3,21,22 Use is advised only in patients with low-to-moderate caries risk, and compomer restorations should be monitored for secondary caries and wear. 26 Favourable clinical performance and low failure rate have been reported over two to three years for one compomer, suggesting it is an amalgam alternative in Class II restorations in primary teeth. 17,27-29 The aim of this study was to examine the relative utilization of amalgam and tooth-coloured restorative materials in children by two groups of clinicians: specialist paediatric dentists and general practitioners who treat children. An observational study using a cross-sectional design was conducted. The objectives were to investigate the current utilization of amalgam and tooth-coloured restorative materials in children and to examine the basis of material selection by clinicians. MATERIALS AND METHODS The questionnaire Relevant issues were identified and a trial questionnaire was prepared; a focus group (six paediatric dentistry postgraduate students) was then conducted to test the questionnaire for content, clarity and validity. The final three-part questionnaire (copies of the questionnaire are available from the corresponding author) contained 29 items. The first part recorded biographic and demographic data of participants (age range, gender, practice type, working sector, number of children seen per week, age range of children seen and main behaviour management approaches). The second part assessed patterns of amalgam usage, influences of parental/child opinions on material choice, relative influence of factors affecting material choice by participant, factors most important to participants in material choice for a vital primary tooth and a vital first permanent molar for several types of restorations, advantages of tooth-coloured materials to participant, the participant s favorite brands of materials, and effects of the NHMRC recommendations. The third part contained six hypothetical clinical scenarios (brief descriptions with diagrams and material options) presenting lesions of various sizes, sites and depths in primary molars with otherwise optimal conditions. Participants choices of materials (fissure sealant, preventive resin restoration, glass ionomer cement, resin-modifed glass ionomer cement, composite resin, compomer, amalgam, stainless steel crown), and cavity preparations (traditional Class II with occlusal dovetail, tunnel, slot preparation with occlusal access) were examined. Study sample Two convenience samples of clinicians were chosen on the basis of availability for comparative study: members of the Australasian Academy of Paediatric Dentistry (hereafter termed AA; specialist paediatric dentists and postgraduate students in paediatric dentistry), and members of the Australian and New Zealand Society of Paediatric Dentistry, Victorian Branch (hereafter termed SPD; general dentists who treat children; this group also included some dental therapists who were SPD members and employed in private practices). Questionnaires (with an explanatory letter) were distributed to all AA members (n=55); 44 questionnaires were hand-distributed at an AA meeting (February, 2002) and 11 questionnaires were mailed to absent members. Questionnaires (and explanatory letter) were mailed to SPD members (n=50; 34 general dentists and 16 dental therapists). The Victorian AA members were not re-surveyed in the SPD survey. 222 Australian Dental Journal 2003;48:4.

3 Table 1. Distribution of study sample by biographic and demographic factors Australasian Academy Paediatric Dentistry ANZ Society of Paediatric Dentistry Biographic and demographic (AA) distribution (SPD) distribution factors (n=44) (n=34) N (valid %) N (valid %) Gender: Males 22 (50)1 11 (32)1 Females 22 (50)1 23 (68)1 Age range (years): (23)1 5 (15) (34)1 10 (30) (29)1 12 (35) (13)1 7 (20)1 Practice type: Specialist paediatric dentists 38 (86)1 Paediatric dentistry postgraduate students 6 (14)1 General dentists 23 (68)1 Dental therapists 11(32)1 Working sector: Public only 15 (34)1 8 (23)1 Private only 8 (18)1 16 (47)1 Both public and private 21 (48)1 10 (30)1 Number of children usually seen per week:* (7)1 19 (61) (27)1 4 (12) (37)1 7 (22) (29)1 1 (5)1 Age range of children usually seen (years): (93)1 24 (71) (100) 30 (88) (86)1 30 (88) (65)1 26 (76)1 Two most often used management approaches: In dental chair with/without LA 27 (63)1 34 (100) General anesthesia in hospital 29 (67)1 5 (15)1 In dental chair with LA and N 2 O 21 (49)1 6 (17)1 In dental chair with LA and sedation other than N 2 O 4 (9)1 2 (6)1 *Three missing answers in AA group; Multiple responses accepted; one missing answer in AA group; LA and N2O/O2: Local anesthesia and nitrous oxide/oxygen analgesia. Data entry and analysis Data were entered onto spreadsheets and examined statistically using SPSS v.10.0 for Windows (SPSS Japan Inc, Tokyo, Japan) and Minitab (MINITAB Statistical Software, 2000, Release 13 for Windows, Pennsylvania, USA). Group responses were summarized as frequencies and comparisons were made using non-parametric statistics (Pearson s Chi Square with continuity correction or Fisher s Exact test; both tests two-sided, xa=0.05). Clinician age was classified post hoc as a dichotomous variable (21-40 years, years) for cross-tabulating scenario responses. RESULTS Distribution of responses and profiles of respondents For the AA group, 36 responses were collected at the meeting (81 per cent) and eight responses were received by mail (72 per cent), resulting in 44 responses (80 per cent). For the SPD group, 34 responses were received by mail (68 per cent). The overall response rate was 74 per cent. The AA group was equally distributed by gender; the SPD group contained more females (68 per cent) than males (32 per cent; Table 1). Most respondents were aged years. The AA respondents were either specialist paediatric dentists (86 per cent) or postgraduate students in paediatric dentistry (14 per cent); SPD respondents were either general dentists (68 per cent) or dental therapists (32 per cent). Most AA respondents (48 per cent) worked in both public and private practice; most SPD respondents (47 per cent) worked in private practice only. Most AA respondents (66 per cent) attended 31 or more children per week; most SPD respondents (61 per cent) attended 20 or fewer children per week (Table 1). Most respondents attended children aged 1-10 years. More SPD respondents than AA respondents attended children aged years. General anesthesia in hospital was the most frequently used management approach among specialist paediatric dentists (67 per cent), followed by treating patients in the dental chair with or without local anesthesia (63 per cent; Table 1). All SPD respondents treated children in the dental chair with or without local anesthesia (100 per cent). More AA respondents (58 per cent) used nitrous oxide analgesia or sedation than SPD respondents (23 per cent). Choice of restorative material Almost all respondents (AA: 91 per cent, SPD: 91 per cent) reported finding a successful alternative material to amalgam in posterior teeth and almost all (AA: 89 per cent; SPD: 97 per cent) reported using toothcoloured materials exclusively or more frequently than amalgam (Table 2). Australian Dental Journal 2003;48:4. 223

4 Table 2. Distribution of study sample by factors affectig choice of restorative materials Australasian Academy Paediatric Dentistry ANZ Society of Paediatric Dentistry Factors affecting choice of (AA) distribution (SPD) distribution restorative materials (n=44) (n=34) N (valid %) N (valid %) Successful alternatives to amalgam found for use in posterior teeth: Yes 40 (91) 31(91) No 4 (9) 3 (9) Patterns of usage of dental materials (other than stainless steel crown) in posterior teeth: Amalgam only 1 (2) 1 (3) More amalgam than tooth-coloured materials 4 (9) 0 (0) More tooth-coloured materials than amalgam 27 (62) 25 (73) Tooth-coloured materials only 12 (27) 8 (24) Main reasons for use of tooth-coloured material for posterior teeth:* Aesthetics superior to amalgam 31 (72) 21 (62) Fluoride release 21 (49) 28 (82) Longevity as good as amalgam 14 (33) 1 (3) Tooth does not need pulp therapy 13 (30) 3 (9) Most influential factors in choosing a restorative material (in order of extent of influence):* 1. Cavity preparation 32 (73) 22 (71) 2. Previous success with material 24 (55) 14 (45) 3. Research reports and journal articles 19 (43) 14 (45) 4. Colleague appraisal 13 (30) 10 (32) *Multiple responses accepted; one missing answer in AA group; three missing answers in SPD group. Of seven reasons provided, the two most frequently chosen for using tooth-coloured materials in posterior teeth were aesthetics superior to amalgam (AA: 72 per cent, SPD: 62 per cent) and fluoride release (AA: 49 per cent, SPD: 82 per cent; Table 2). The least frequent reason was radiopacity as good as amalgam (not tabulated). The three most influential factors in material choice for both groups were cavity preparation, previous success with material and research reports and journal articles (Table 2). The availability of the material, company speaker and information from the manufacturer had least influence in material choice (not tabulated). Most respondents (AA: 86 per cent, SPD: 91 per cent) advised parents of materials chosen (Table 3). While parental preferences were considered by most respondents (AA: 81 per cent, SPD: 97 per cent), only five respondents acquiesced to parental material requests against their clinical judgment; most agreed sometimes (AA: 55 per cent, SPD: 66 per cent), and some (AA: 42 per cent, SPD: 22 per cent) kept to their clinical judgment at all times. Most respondents (AA: 57 per cent, SPD: 76 per cent) advised the child about material choice. Although patterns were similar for both groups, the extent of child/parental involvement in material choice was greater for SPD respondents. Clinicians who considered parental preferences were significantly more likely to acquiesce to parental requests (x 2 =9.844, df=2, p=0.005) than those who did not. Factors influencing material choices for vital primary teeth Seven factors (child age, child behaviour, caries experience, moisture control, restoration retention, oral hygiene-plaque control, and parental motivation) were provided for participants to select from and rank the first Table 3. Distribution of study sample by factors relating to material advice to parents and children Australasian Academy of Paediatric Dentistry ANZ Society of Paediatric Dentistry Factors related to material advice (AA) distribution (SPD) distribution (n=44) (n=34) N (valid %) N (valid %) Advise parents about restorative materials being used: Yes 38 (86)* 31 (91)* No 6 (14)* 3 (9)* Consider parental preferences for restorative material: Yes 31 (81)* 31 (97) No 7 (19) 1 (3)* Acquiesce to parental request for a restorative material: Sometimes 21 (55)* 21 (66) Yes 1 (3)* 4 (12) No 16 (42)* 7 (22) Advise child of choice of restorative material: Sometimes 2 (5)* 3 (9)* Yes 25 (57)* 26 (76)* No 17 (38)* 5 (15) *Six missing answers; two missing answers. 224 Australian Dental Journal 2003;48:4.

5 Per cent distribution Fig 1. Distribution of first ranked factors in choice of restorative material for seven restorations in vital primary teeth by AA (n=44) and SPD (n=34) respondents. Per cent distribution Fig 2. Distribution of second ranked factors in choice of restorative material for seven restorations in vital primary teeth by AA (n=44) and SPD (n=34) respondents. two factors most influencing their material choices for restoring vital primary teeth (Fig 1 and 2). Among both groups, child age was cited most frequently (AA: per cent, SPD: per cent) as the first ranked factor influencing choice of restorative material for Class I (small and large), Class II (small and large), Class III (small), Class IV (large) and Class V (small) restorations (Fig 1). For all seven restorations, caries experience was cited more frequently by SPD respondents than by AA respondents (SPD: per cent, AA: per cent), and moisture control was cited more frequently by SPD respondents than by AA respondents (SPD: per cent, AA: 5-26 per cent). The factors child behaviour and restoration retention were cited as first ranked factors in a few instances (Fig 1). Comparison of group distributions of first ranked factors showed statistically significant differences for Class I small restorations (x 2 =10.379, df=4, p=0.017) and for Class I large restorations (x 2 =10.405, df=4, p=0.017). No statistically significant differences in distributions were seen for Class II small restorations (x 2 =6.846, df=4, p=0.131), Class II large restorations (x 2 =3.841, df=4, p=0.484), Class III small restorations (x 2 =3.548, df=3, p=0.354), Class IV large restorations (x 2 =1.971, df=4, p=0.851) and Class V small restorations (x 2 =3.331, df=3, p=0.368). Further examination of the statistically significant distributions for Class I small restorations indicated that AA respondents were significantly more likely to rank child age as the first factor than SPD respondents (Fisher Exact test, p=0.01), and SPD respondents were more likely to rank moisture control as first factor than AA respondents (approaching significance, Fisher Exact test, p=0.06). Further examination of the statistically significant distributions for Class I large restorations indicated that AA respondents were significantly more Australian Dental Journal 2003;48:4. 225

6 Per cent distribution Fig 3. Distribution of first ranked factors in choice of restorative material for four restorations in vital first permanent molars by AA (n=44) and SPD (n=34) respondents. likely to rank child age as the first factor than SPD respondents (Fisher Exact test, p=0.03), and SPD respondents were significantly more likely to rank moisture control as first factor than AA respondents (Fisher Exact test, p=0.006). Respondents differed in their second ranked factors influencing choice of restorative material, with AA respondents (26-41 per cent) consistently citing caries experience for Class I (small and large), Class II (large), Class III (small), Class IV (large) and Class V (small) restorations and moisture control for Class II (small) and Class V (small) restorations (Fig 2). The SPD respondents were more variable in selecting second ranked factors; child behaviour was cited for Class I (small and large), Class III (small) and Class IV (large) restorations, and moisture control for Class II (small and large) restorations. The factor child behaviour was cited more frequently by SPD respondents than AA respondents (SPD: per cent, AA: per cent). The factors oral hygiene-plaque control and parental motivation were cited as second ranked factors in a few instances (Fig 2). Factors influencing material choices for vital first permanent molars Seven factors (child age, child behaviour, caries experience, moisture control, restoration retention, oral hygiene/plaque control, and parental motivation) were provided for participants to select from and rank the first two factors most influencing their material choices for restoring vital first permanent molars (Fig 3 and 4). Among both groups, caries experience was cited most frequently (AA: per cent, SPD: per cent) as the first ranked factor influencing choice of Table 4. Preferred and most user-friendly brands of tooth-coloured restorative materials* Material Preferred brand First choice for user-friendly Second choice for user-friendly N (valid %) brand N (valid %) brand N (valid %) AA SPD AA SPD AA SPD (n=44) (n=34) (n=44) (n=34) (n=44) (n=34) Glass ionomer cement Fuji IX TM Fuji IX TM Fuji IX TM Fuji IX TM Ketac Molar Quick TM Fuji II TM 17 (42) 26 (76) 26 (72) 25 (83) 18 (50) 11 (37) Composite resin Z100 TM Herculite TM Z100 TM Herculite TM Filtek 250 TM Z100 TM 21 (52) 11 (33) 21 (58) 11 (42) 11 (31) 9 (35) Resin modified glass ionomer cement Fuji II LC TM Fuji II LC TM Fuji II LC TM Fuji II LC TM Photac-Fil Quick TM Photac-Fil Quick TM 30 (73) 23 (70) 29 (80) 21 (80) 16 (44) 16 (61) Compomers Dyract TM Dyract TM Dyract TM Dyract TM F2000 TM Freedom TM 28 (78) 17 (85), 24 (89) 14 (82) 10 (37) 5 (29) *Multiple responses accepted; four missing answers; eight missing answers; one missing answer;,14 missing answers; 17 missing answers. Manufacturers: Fuji IX TM, GC Corporation, Singapore; Ketac Molar Quick TM 3M ESPE Co, USA; Fuji II TM, GC Corporation, Singapore; Z100 TM, 3M ESPE Co, USA; Herculite TM, Kerr, USA; Filtek Z250 TM, 3M ESPE Co, USA; Fuji II LC TM, GC Corporation, Singapore; Photac Fil Quick TM, 3M ESPE Co, USA; Dyract TM, Dentsply, USA; F2000 TM, 3M ESPE Co, USA; Freedom TM, SDI Ltd, Australia. 226 Australian Dental Journal 2003;48:4.

7 Per cent distribution Fig 4. Distribution of second ranked factors in choice of restorative material for four restorations in vital first permanent molars by AA (n=44) and SPD (n=34) respondents. restorative material for Class I (small and large) and Class II (small and large) restorations (Fig 3). For all four restorations, moisture control was cited more frequently by SPD respondents than by AA respondents (SPD: per cent; AA: 9-20 per cent), and child age was cited more frequently by AA respondents than SPD respondents (AA: per cent, SPD: 6-16 per cent). The factors child behaviour, restoration retention and parental motivation were cited as first ranked factors in a few instances (Fig 3). Comparison of group distributions of first ranked factors showed no statistically significant differences for Class I small restorations (x 2 =6.778, df=4, p=0.111), Class I large restorations (x 2 =7.045, df=4, p=0.100) or Class II small restorations (x 2 =5.585, df=4, p=0.221), but a statistically significant difference in the distributions for Class II large restorations was seen (x 2 =9.489, df=4, p=0.042). Further examination of the statistically significant distribution for Class II large restorations indicated that AA respondents were significantly more likely to rank child age as the first factor than SPD respondents (Fisher Exact test, p=0.02), and SPD respondents were more likely to rank moisture control first than AA respondents (approaching significance, Fisher Exact test, p=0.06). Among both groups, moisture control was cited most frequently (AA: per cent, SPD: per cent) as the second ranked factor influencing choice of restorative material for Class I (small and large) and Class II (small and large) restorations (Fig 4). For all four restorations, caries experience was cited more frequently as a second ranking factor by AA respondents than by SPD respondents (AA: per cent, SPD: 3-10 per cent), and restoration retention was cited more frequently by SPD respondents than AA respondents (SPD: per cent, AA: 7-17 per cent). The factors child age and oral hygiene-plaque control were cited as second ranking factors in a few instances (Fig 4). Effect of NHMRC recommendations Most participants (AA: 75 per cent, SPD: 82 per cent; not tabulated) were aware of the NHMRC recommendations on using alternatives to amalgam where appropriate. Among aware AA respondents, 56 per cent thought the recommendations gave them more freedom than previously in using tooth-coloured materials, although 62 per cent thought the recommendations did not assist decision-making in borderline cases. In contrast, 62 per cent of aware SPD respondents thought their decision-making was eased in such cases. Clinicians who considered the recommendations gave them more freedom were significantly more likely to use tooth-coloured materials in borderline cases (x 2 =12.680, df=1; p=0.001). The recommendations were significantly more likely to ease decision-making for SPD respondents than for AA respondents (x 2 =4.549, df=1; p=0.045). Preferred brands of materials The preferred glass ionomer cement brand for both groups was Fuji IX TM (GC Corporation, Singapore; Table 4). Although a wide range of glass ionomer cement brands were favourites of AA respondents, SPD respondents favoured Fuji IX TM (76 per cent). A wide range of composite resins were favoured by AA respondents, with 52 per cent preferring Z100 TM (3M Australian Dental Journal 2003;48:4. 227

8 Table 5. Hypothetical clinical scenarios (all cases are of a co-operative child with good oral hygiene, no other lesions, living in a fluoridated area and using a fluoridated tooth paste) Scenario Lesion Material choices (1) Four year-old child Occlusal lesions just into enamel on mandibular F Sealant, PR Rest n, GIC, RMGIC, primary second molar: C R, Comp r, Amalgam, SSC, Other. (2) Five year-old child Occlusal lesions half way to DEJ on mandibular F Sealant, PR Rest n, GIC, RMGIC, primary second molar: C R, Comp r, Amalgam, SSC, Other. (3) Six year-old child Occlusal lesion just into dentine on mandibular F Sealant, PR Rest n, GIC, RMGIC, primary second molar: C R, Comp r, Amalgam, SSC, Other. (4) Five year-old child Occlusal lesion half way to pulp on mandibular F Sealant, PR Rest n, GIC, RMGIC, primary second molar: C R, Comp r, Amalgam, SSC, Other. (5) Eight year-old child Proximal lesion half way to pulp on mandibular F Sealant, PR Rest n, GIC, RMGIC, primary second molar: C R, Comp r, Amalgam, SSC, Other. (6) Eight year-old child Two proximal lesions half way to pulp on mandibular F Sealant, PR Rest n, GIC, RMGIC, primary second molar C R, Comp r, Amalgam, SSC, Other. Abbreviations: F Sealant=Fissure sealant; PR Rest n= Preventive resin restoration; IC=Glass ionomer cement; RMCIC=resin modified glass ionomer cement; C R= composite resin; Comp r=compomer; SSC=Stainless steel crown. ESPE Co, St Paul, Minnesota, USA) and 33 per cent of SPD respondents favouring Herculite TM (Kerr, USA). The preferred resin-modified glass ionomer cement was Fuji II LC TM (GC Corporation, Singapore), and Dyract TM (Dentsply, York, Pennsylvania, USA) was the preferred compomer. More consistency was noted in the SPD group than the AA group, with most SPD respondents choosing the same brand as their favourite for every material type. These brands were also considered the most user-friendly. Hypothetical clinical scenarios Scenario 1: Preferred material for occlusal lesions (just into enamel) on primary molar (Table 5) Although a wide material range was chosen, fissure sealant was favoured (AA: 50 per cent, SPD: 53 per cent; Table 6). Material choice was unrelated to clinician group (x 2 =2.632, df=3, p=0.466). Although both groups preferred fissure sealant equally, younger respondents were significantly more likely to choose preventive resin restoration/composite resin/compomer (x 2 =6.457, df=3, p=0.037) than older respondents, who were more likely to choose glass ionomer cement. Scenario 2: Preferred material for occlusal lesions (half way to dentino-enamel junction) on primary molar (Table 5) A preventive resin restoration was preferred (AA: 48 per cent, SPD: 35 per cent; Table 6). Material choice was unrelated to either age group (x 2 =2.175, df=2, p=0.359), or clinician group (x 2 =4.235, df=3, p=0.322). 228 Australian Dental Journal 2003;48:4.

9 Table 6. Preferred restorative material/procedure in hypothetical clinical scenarios in primary molar teeth First choice for material/procedure Second choice for material/procedure Hypothetical clinical scenarios N (valid %) N (valid %) AA (n=44) SPD (n=34) AA (n=44) SPD (n=34) 1. Occlusal lesions (just into enamel) F Sealant F Sealant PR Rest n PR Rest n 22 (50) 18 (53) 10 (23) 6 (17) 2. Occlusal lesions (half way to DEJ) PR Rest n PR Rest n F Sealant/CR/GIC GIC/RMGIC 21 (48) 12 (35) 6 (13) 7 (20) 3. Occlusal lesion (just into dentine) PR Rest n GIC CR PR Rest n/rmgic 18 (41) 16 (47) 8 (18) 7 (20) 4. Occlusal lesion (half way to pulp) PR Rest n GIC GIC/RMGIC/ CR/Comp r RMGIC 9 (20) 19 (56) 6 (14) 6 (17) 5. Proximal lesion (extending half way to pulp) Comp r GIC GIC/RMGIC/CR/Am RMGIC 11 (26)* 18 (58) 7 (17)* 8 (26) 5.1 Cavity preparation Slot Slot Trad Class II Tunnel/Trad Class II 25 (76) 23 (72)* 7 (21) 4 (12)* 6. Two proximal lesions (extending SSC GIC Comp r RMGIC/CR half way to pulp) 22 (51) 16 (47) 6 (14) 6 (18) *Two missing answers; one missing answer; three missing answers; 11 missing answers. Abbreviations: F Sealant=Fissure sealant; PR Rest n=preventive resin restoration; GIC=Glass ionomer cement; RMGIC=resin modified glass ionomer cement; CR=composite resin; Am=Amalgam; Comp r=compomer; SSC=Stainless steel crown; Trad Class II=Traditional Class II. Scenario 3: Preferred material for occlusal lesion (just into dentine) on primary molar (Table 5) Although a wide material range was chosen, a preventive resin restoration (AA: 41 per cent) or glass ionomer cement (SPD: 47 per cent; Table 6) were preferred. Material choice was unrelated to age group (x 2 =2.304, df=2, p=0.306). The SPD respondents were significantly more likely to choose glass ionomer cement (x 2 =12.648, df=2, p=0.001) than AA respondents, who were more likely to choose preventive resin restoration/composite resin/compomer. Scenario 4: Preferred material for an occlusal lesion (half way to pulp) on primary molar (Table 5) A preventive resin restoration was favoured by AA respondents (20 per cent), followed by glass ionomer cement, composite resin and compomer (Table 6); SPD respondents preferred glass ionomer cement (56 per cent). Material choice was unrelated to age group (x 2 =3.924, df=2, p=0.142). The SPD respondents were significantly more likely to choose glass ionomer cement (x 2 =13.667, df=2, p=0.000) than AA respondents, who were more likely to choose preventive resin restoration/composite resin/compomer or amalgam/stainless steel crown. Scenario 5: Preferred material and cavity preparation for a proximal lesion on primary molar (Table 5) A wide material range was chosen, with a toothcoloured material preferred (AA: 76 per cent, SPD: 97 per cent; not tabulated). A compomer was preferred by AA respondents (26 per cent; Table 6) followed by glass ionomer, composite resin or amalgam. A glass ionomer cement was chosen by 84 per cent SPD respondents (conventional: 58 per cent, resin-modified: 26 per cent). A few AA respondents chose amalgam (9 per cent), or a stainless steel crown (4 per cent). Material choice was related significantly to age group, with younger respondents more likely to choose composite resin/compomer or amalgam/stainless steel crown (x 2 =6.401, df=2, p=0.048) than older respondents, who were more likely to choose glass ionomer cement. The SPD respondents were significantly more likely to choose glass ionomer cement (x 2 =16.495, df=2, p=0.000) than AA respondents, who were more likely to choose composite resin/compomer and amalgam/ stainless steel crown. A slot preparation with occlusal access was preferred by respondents choosing a tooth-coloured material (AA: 76 per cent, SPD: 72 per cent), followed by a traditional Class II dovetail preparation (AA: 21 per cent, SPD: 14 per cent; Table 6). Cavity design was unrelated to age group (x 2 =3.163, df=2, p=0.190). The tunnel preparation (five respondents) was significantly more likely to be used by SPD respondents (x 2 =5.902, df=2, p=0.037) than AA respondents. Scenario 6: Preferred material for two proximal lesions (half way to pulp) on primary molar (Table 5) Material choices varied widely; among AA respondents a stainless steel crown (51 per cent) was preferred, followed by compomer (14 per cent); few (9 per cent) chose amalgam or glass ionomer cement (Table 6). Among SPD respondents, the preferred material was glass ionomer cement (conventional: 47 per cent, resin-modified: 18 per cent). Younger respondents were significantly more likely to choose composite resin/compomer and amalgam/stainless steel crown (x 2 =8.070, df=2, p=0.020) than older respondents, who were more likely to choose glass ionomer cement. The SPD respondents were significantly more likely to choose glass ionomer cement (x 2 =23.637, df=2, p=0.000) than AA respondents, who preferred composite resin/compomer and amalgam/stainless steel crown. DISCUSSION Utilization of restorative materials in children Amalgam appeared to have limited use in Class I and II restorations in primary molars, especially among Australian Dental Journal 2003;48:4. 229

10 SPD respondents. In contrast, glass ionomer cement was favoured in moderate-sized Class I and II restorations, supporting the observations of other studies. 7,9,16,30,31 While the present study posed hypothetical clinical scenarios, these studies surveyed practising dentists concerning all restorations placed during a specified period. A study from Finland reported glass ionomer cement as the predominant material used in children younger than 17 years, placed in 91 per cent of primary tooth restorations and 47 per cent permanent tooth restorations. 10 The two most common restorative materials reported in a 1998 study of primary dentitions in Sweden were compomer and glass ionomer cement. 32 A Norwegian study in 2002 reported 80 per cent of restorations in primary teeth were of tooth-coloured materials (predominantly lightcured). 30 A questionnaire-based study of US paediatric dentists published in 2002 reported resin-based materials were most frequently selected for Class I and II restorations. 7 A UK study of clinicians case notes from 1999 reported 61 per cent of first primary molars and 55 per cent of second primary molars were restored with glass ionomer cement. 16 In 2001, a European study compared restorative materials used on primary teeth by two undergraduate dental school clinics (in Nice and Amsterdam) and reported that composite resin was generally used on anterior teeth and amalgam on primary molars in Nice, while compomer was preferred for all primary dentition restorations in Amsterdam. 31 However, as the cohorts were dental students, the study reflected dental school teaching rather than the preferences of dentists in the community. In the present study, there was a trend towards more frequent hypothetical use of conventional glass ionomer cement than resin-modified glass ionomer cement in Class II restorations in primary molars with more than three years to exfoliation. This does not accord with recommendations in recent literature concluding that conventional glass ionomer cement is inappropriate for use in primary molars due to its low tensile strength and poor long-term performance. 2,14,17,18,33 The longevity of Class II glass ionomer cement restorations could not be compensated for by the reduced caries progression and lessened need for restoration of adjacent surfaces. 18 Conversely, resinmodified glass ionomer cement has been suggested as a suitable alternative to amalgam for primary molars. 3,14,19,20 Considering it is a newly developed material, the number of respondents in the present study choosing compomer for Class II restorations was high. This may reflect the favourable results from two to three year studies, which concluded that compomers are suitable alternatives to amalgam or other tooth-coloured materials when used in Class II restorations in primary molars. 3,17,27-29,34 One clinical study found a compomer (Dyract TM, Dentsply, Germany) had a higher mean survival time and performed significantly better than a glass ionomer cement (Chemfil Superior TM, Dentsply, Germany) in terms of anatomical form, marginal integrity, cavo-surface discolouration and maintenance of proximal contact. 17 The present study also demonstrated a low hypothetical use of stainless steel crowns, especially among SPD respondents. Scenario 6 featured a primary molar with two proximal lesions, usually considered an indication for a stainless steel crown. 6,35-37 However, only 25 per cent of respondents (all paediatric specialist dentists) would choose a stainless steel crown. A case note study published in 1988 recommended that if a choice exists between placing a Class II amalgam and a stainless steel crown in a child older than four years, the likelihood of success of a stainless steel crown is approximately twice that of amalgam, for a similar lifespan. 38 Recent literature still considers a stainless steel crown to be the most durable restoration in the primary dentition. 39 Basis of material selection The present study sought to explore participants basis of material selection. However, since this is usually a complex interaction of experience and epidemiological, cultural, socio-economical and educational factors, the current findings based on a small sample size should be considered as exploratory rather than a full account of the basis of material selection. The more frequent proposed use of glass ionomer cement by older clinicians may reflect long familiarity with the material and its advantages over earlier materials. An association was noted between respondents most influential factors in material choice for Class II restorations and their proposed choices. Those with a greater concern for child behaviour and moisture control tended to choose glass ionomer cement. As glass ionomer cement is adhesive to dentine, it could be preferred in situations where unco-operative child behaviour could compromise cavity preparation and moisture control. In contrast, respondents (typically specialist paediatric dentists) for whom caries experience and child age were more important tended to choose amalgam and stainless steel crowns. With more experience in behaviour management, cavity preparation and moisture control, these respondents may prefer restoration durability to take precedence. The apparent preference for tooth-coloured materials in primary molars may reflect declining caries experience, favourable scientific reports on these materials, and the NHMRC recommendations. Declining caries experience has resulted in smaller carious lesions, which favour the use of tooth-coloured materials. These considerations may have affected material choice of respondents for whom the most influential factors were cavity preparation, previous success with material and research reports and journal articles. The aesthetics and fluoride release of toothcoloured materials may also have contributed to this shift. The NHMRC recommendations per se may have 230 Australian Dental Journal 2003;48:4.

11 promoted tooth-coloured materials, as most respondents reported the recommendations gave them more freedom in use of such materials. Parents and children had a modest role in respondents material decision-making in the present study, in contrast to the strong influence of opinions of adult patients on material selection. 10 Choices of restorative materials in primary teeth by groups Wide variations in proposed material choices were found between the two groups. Amalgam and stainless steel crowns appear to be no longer considered by SPD respondents for restoration of moderate- to large-sized occlusal lesions and proximal lesions in primary molars, with glass ionomer cement becoming the preferred material. The use of resin-based and resinmodified materials was also significantly lower in this group than in the AA group. These observations on the SPD group may reflect less experience in treating children and unavailability of sedation or general anaesthesia. Their greater hypothetical use of toothcoloured materials may also reflect a greater response to the NHMRC recommendations. Of note, the dental therapists included in the sample were all employed in private practices where they had independence in material selection. Implications of the study It is acknowledged that the total sample size of 78 respondents in the present study was small and limited by necessity to two convenience samples. However, the 44 AA respondents were drawn from all states of Australia, New Zealand and Hong Kong and represented 80 per cent of the total membership (55 members) of the Australasian Academy of Paediatric Dentistry (all specialist paediatric dentists). The 34 SPD respondents were drawn only from the Victorian Branch of the Australian and New Zealand Society of Paediatric Dentistry (primarily general dentists) and the responses represented only 68 per cent of the membership. The trends described should be examined further with a larger sample drawn from other areas of Australia in order to be accepted as national trends for general dentists and dental therapists. The few previous studies investigating material selection and restoration placement in children used a practice-based approach, with dentists providing information on all restorations placed during a given time period. 7,9,16,30,31 The present study posed hypothetical clinical scenarios, allowing anonymity of response and differentiation of material choices. Studies suggest a discrepancy between the teaching of restorative paediatric dentistry in dental schools and the actual utilization of materials by paediatric dentists. In a report published in 2001 on the teaching of Class I and II restorations in primary teeth in North American dental schools, amalgam continued to be the most frequently recommended material. 40 In contrast, a 2002 report indicated that paediatric dentists in Florida, USA preferred resin-based materials for these restorations. 7 To date, there are no comparable reports on the teaching of Class I and II restorations in primary teeth in Australian dental schools; whether a similar discrepancy exists between teaching and practice remains to be investigated. A consensus report on restorative dentistry prepared for the American Academy of Pediatric Dentistry in 2002 expressed the need for consensus and guidelines in material selection and techniques in USA. 6 The wide range of materials chosen for the hypothetical clinical scenarios by clinicians in the present study supports this need for guidelines on material selection, and suggests the need for longitudinal studies to follow actual clinical outcomes of the materials chosen. CONCLUSIONS Based on the questionnaire responses and the hypothetical clinical scenarios, tooth-coloured materials were the most popular choices for restorations of the primary dentition; the proposed use of amalgam and stainless steel crowns was low. Glass ionomer cement was the most popular tooth-coloured material chosen and compomers appeared to be gaining popularity for Class II restorations. Members of AA (specialist paediatric dentists) were more likely to choose resin-based materials, amalgam or stainless steel crowns, while members of SPD (general dentists who treat children, and dental therapists) were more likely to choose glass ionomer cement. The hypothetical choice of a restorative material for Class II restorations was influenced by clinician factors. Clinicians with greater concern for child behaviour and moisture control tended to choose glass ionomer cement while clinicians with greater concern for caries experience and child age tended to choose amalgam and stainless steel crowns. The wide range of materials chosen for each hypothetical clinical scenario suggests the need for guidelines on material selection in paediatric dentistry in Australia and the need for longitudinal studies to follow actual clinical outcomes of the materials chosen. ACKNOWLEDGEMENTS The participating clinicians in this study are thanked with gratitude. 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