The Hall Technique; a randomized controlled clinical trial of a novel method of managing carious primary molars in general dental practice: acceptability of the technique and outcomes at 23 months

Abstract

Background: Scotland has high levels of untreated dental caries in primary teeth. The Hall Technique is a simplified method of managing carious primary molars using preformed metal crowns (PMCs) cemented with no local anaesthesia, caries removal or tooth preparation. This study compared the acceptability of the Hall Technique for children, their carers, and dentists, and clinical outcomes for the technique, with conventional restorations.

Methods: General dental practice based, split mouth, randomized controlled trial (132 children, aged 3-10). General dental practitioners (GDPs, n = 17) in Tayside, Scotland (dmft 2.7) placed conventional (Control) restorations in carious primary molars, and Hall Technique PMCs on the contralateral molar (matched clinically and radiographically). Dentists ranked the degree of discomfort they felt the child experienced for each procedure; then children, their carers and dentists stated which technique they preferred. The teeth were followed up clinically and radiographically.

Results: 128 conventional restorations were placed on 132 control teeth, and 128 PMCs on 132 intervention teeth. Using a 5 point scale, 118 Hall PMCs (89%) were rated as no apparent discomfort up to mild, not significant; for Control restorations the figure was 103 (78%). Significant, unacceptable discomfort was recorded for two Hall PMCs (1.5%) and six Control restorations (4.5%). 77% of children, 83% of carers and 81% of dentists who expressed a preference, preferred the Hall technique, and this was significant (Chi square, p < 0.0001). There were 124 children (94% of the initial sample) with a minimum follow-up of 23 months. The Hall PMCs outperformed the Control restorations:a) 'Major' failures (signs and symptoms of irreversible pulpal disease): 19 Control restorations (15%); three Hall PMCs (2%) (P < 0.000);b) 'Minor' failures (loss of restoration, caries progression): 57 Control restorations (46%); six Hall PMCs (5%) (P < 0.000)c) Pain: 13 Control restorations (11%); two Hall PMCs (2%) (P = 0.003).

Conclusion: The Hall Technique was preferred to conventional restorations by the majority of children, carers and GDPs. After two years, Hall PMCs showed more favourable outcomes for pulpal health and restoration longevity than conventional restorations. The Hall Technique appears to offer an effective treatment option for carious primary molar teeth.

Trial registration number: Current Controlled Trials ISRCTN47267892 - A randomized controlled trial in primary care of a novel method of using preformed metal crowns to manage decay in primary molar teeth: the Hall technique.

Figure 1

Clinical photographs of a Hall PMC being fitted: a) carious primary molar tooth 74 (LLD) to be fitted with a Hall PMC; b) PMC being tried over occlusal surface of tooth to guage size (guaze providing airway protection). The crown is now filled with glass ionomer cement and placed firmly over the tooth; c) patient biting on cotton roll to push crown between contact points and maintain pressure until cement sets; d) buccal view, and e) occlusal view of the fitted Hall PMC.

Figure 2

CONSORT (Consolidated Standards of Reporting Trials) diagram showing the flow of participants through each stage of the randomized trial.

Figure 3

Radiographs of two matched carious lesions in tooth 85 (LRE) – radiograph a) and tooth 75 (LLE) – radiograph b). Patient randomisation number 92.

Figure 4

Dentists' estimation of discomfort experienced by child (n = 132 children).

Figure 5

Lower arch with Hall PMC on tooth 85 (LRE) and Control restoration (mesio-occlusal composite) in tooth 75 (LLE). Patient randomisation number 92.

Figure 6

Clinical photograph of 'Minor' failure of Control restoration on tooth 75 (LLE); restoration lost and caries progression. Patient randomisation number 92.

Figure 7

Clinical photograph of Control restoration 'Major' failure with sinus visible. Patient randomisation number 19.

Figure 8

Patient recruitment pattern by individual GDP (n = 132 patients).

Figure 9

Histogram of age of children on entry to trial (n = 132 children).

Figure 10

Mean values for distribution of caries lesions for study teeth (n = 229).

Figure 11

Radiograph of Hall PMC on tooth 74 (LLD) recorded as satisfactory fit. Patient randomisation number 7.

Figure 12

Radiograph of Hall PMC on tooth 54 (URD) recorded as unsatisfactory fit. Patient randomisation number 34.

Figure 13

Patient/carer/dentist treatment preference (n = 396 for 132 treatment events).

Figure 14

Clinical photograph of a patient with six PMCs fitted using the Hall Technique at separate appointments. The occlusion has adjusted to give even contact between the arches.

Figure 15

'Major' failures for Control restorations and Hall PMCs noted clinically, radiographically or both. Minimum patient follow-up 23 months; range of restoration failure 0–36 months.

Figure 16

Episodes of pain from teeth treated with Control restorations and Hall PMCs. Minimum patient follow-up 23 months; range of pain episodes 0–36 months.

Figure 17

'Minor' failures for Control restorations and Hall PMCs noted clinically, radiographically or both. Minimum patient follow-up 23 months; range of restoration failures 0–36 months.

Figure 18

Estimates of longevity of dental restorations (in permanent and primary teeth). Reprinted with permission from Evidence Based Dentistry, Chadwick et al., 2002: 3; 96–99, Copyright 2002, Macmillan Publishers Ltd.