[Clinical study on prognosis and occlusal evaluation of large area caries of deciduous molars restored by Hall technique].

Abstract

Objective: To evaluate the prognosis of Hall technique and traditional metal pre-crown restoration technique, and to follow up the occlusal changes before and after treatment with Hall technique, so as to provide reference for the promotion of Hall technique. Methods: Children who visited the Department of Pediatric Dentistry, West China Hospital of Stomatology, of Sichuan University from May 2021 to December 2022 were screened according to the inclusion and exclusion criteria. The therapeutic effects of the two groups were followed up at three time points: 1, 2 and 3 months after operation. The observation results were divided into three outcomes: success (crown in place, no symptoms of pulpitis or periapical periodontitis, no obvious abnormality in occlusion, no need for further treatment), partial failure (crown falling off or crown broken, tooth defect can be repaired, reversible pulpitis) and complete failure (irreversible pulpitis or periapical periodontitis, crown falling off and tooth defect irreparable), and statistical analysis was made. At the same time, the Hall technique group was followed up at five time points before operation, immediately after operation, 2 weeks after operation, 4 weeks after operation and 8 weeks after operation respectively, and the occlusion was analyzed by Dental Prescale Ⅱ system. The vertical dimension of occlusion (VDO), overbite coverage and canine relationship were recorded and compared. Three-dimensional finite element method was used to model and analyze the stress of the teeth treated with traditional metal pre-crown treatment and Hall scheme, and the differences between them were compared. Results: Finally, 21 children were included in the Hall technique treatment group, including 12 boys and 9 girls, with age of (5.0±1.4) years. There were 22 children in the traditional metal pre-crown group, including 15 boys and 7 girls, with age of (5.1±1.3) years. There were 0 cases of complete failure and 0 cases of partial failure in the Hall scheme group, 0 cases of complete failure and 0 cases of partial failure in the traditional pre-crown group. There were 0 cases of complete failure and 1 case of partial failure in the Hall scheme group, 0 cases of complete failure and 0 cases of partial failure in the traditional pre-crown group. Hall scheme group failed completely in 1 case and partially in 1 case 3 months after operation, while the traditional pre-crown group failed completely in 0 cases and partially in 0 cases 3 months after operation. There was no significant difference in the incidence of primary index/complete failure and secondary index/partial failure between Hall scheme group and traditional pre-crown group (all P>0.05). The occlusal area and occlusal force of children treated with Hall scheme decreased immediately after operation compared with that before operation, but gradually recovered to the preoperative level at 2 and 4 weeks after operation, in which the occlusal area decreased significantly from (14.79±3.55) mm² before operation to (10.15±3.17) mm² immediately after operation (P=0.001), and recovered to (15.58±3.39) mm² at 8 weeks after operation. The bite force decreased significantly from (436.94±109.59) N before operation to (292.70±96.05) N immediately after operation (P=0.001), and recovered to (441.86±104.31) N at 8 weeks after operation (P=0.999 compared with before operation). Overbite decreased significantly from (2.54±1.05) mm before operation to (1.80±0.94) mm immediately after operation (P=0.044) and then recovered to (2.35±1.02) mm (P=0.962 compared with before operation). The coverage changed from (2.41±0.66) mm before operation to (2.27±0.61) mm immediately after operation (P=0.987) and then recovered to (2.48±0.62) mm (P=0.998 compared with before operation). The canine relationship was (3.12±0.54) mm before operation, and decreased significantly immediately after operation (2.17±0.89) mm (P=0.001), and recovered to (3.05±0.61) mm after 8 weeks (P=0.993 compared with before operation). In the three-dimensional finite element analysis, the maximum stress of all parts of the affected tooth increased immediately after Hall scheme treatment, but with occlusal adjustment, the maximum stress of all parts of the affected tooth decreased, which was similar to that of the traditional metal pre-crown group, and the vertical load and oblique load of pre-crown decreased from 180.11 and 496.16 N to 108.05 and 297.69 N; respectively. The vertical load and oblique load of enamel decreased from 94.83 and 255.94 N to 57.21 and 156.44 N, respectively. The vertical load and oblique load of dentin decreased from 55.19 and 124.77 N to 33.19 and 74.59 N respectively. Conclusions: During the experimental observation period, there is no obvious difference between Hall scheme and traditional metal pre-crown treatment technology in terms of post-treatment occlusion and clinical prognosis, which supports clinical application.