There are many modes to preserve pulpal vitality in teeth with deep caries. Indirect pulp treatment is one such therapeutic modality that attempt to maintain pulp vitality and avoid more extensive treatments.9 The systematic review of Bergenholtz et al.10 showed that there are significant gaps in our knowledge concerning the treatment of the vital pulp with deep carious lesions and this study was carried out to compare two different methods for indirect pulp treatment.
In this study, 32 vital lower permanent first molars with deep caries in 20 children were involved and splitted up into two groups. Group 1 using PAD and group 2 using calcium hydroxide. All children were selected randomly from the outpatient clinic of Pediatric Dentistry and Dental Public Health Department, to unify the socioeconomic and educational levels. There was an equal distribution of the baseline characteristics as the two groups did not vary in socioeconomic and educational levels or demographic parameters and thus any systematic selection bias for the results of the study can be excluded. The high recall rate in the last follow-up period reduced the detection and reporting bias in this study.
Age selection in this study ranged from 6 to 12 years as in young patients, the excellent vascular supply, the presence of odontoblasts and undifferentiated mesenchymal cells, which are responsible of dentinogenetic function, favors tertiary dentin formation in deep carious lesions.11
Since there is no definite evidence that it is essential to reenter the tooth to remove the residual caries, single visit IPT was done for the two groups involved according to several studies using single visit IPT.2,9,12,13
Following pulp capping procedure, the cavity was sealed with glass ionomer and then filled with composite resin as final restoration. Sealing the demineralized dentin with a restoration that offers good peripheral seal and deprives the microorganisms from the oral cavity substrate. This reduces the bacterial count, diversity and arrests the caries process.4 Clinical and radiographic success for both groups were evaluated till one year according to comparable studies.12,13,14
Evaluation was carried on 2, 6, 9, and 12 months for the clinical and radiographic outcomes. Digital radiography was used with a very low dose and exposure time which is much lower than the corresponding regular radiography (nondigital periapical radiographs). Therefore, the digital radiographs taken were approximately equivalent to two regular periapical radiographs of D speed according to Carestream exposure timing reference manual.12 This was accepted by the research ethics committee of the Faculty which coincide with the country’s regulations. In addition, the children were protected with lead apron and paralleling technique with XCP index was used which ensured that the film is placed in proper position. Thus, no retakes were done.
Regarding the results of this study, the clinical and radiographic success for both groups was 100% at all follow-up periods. The good clinical and radiographic success reported here could be attributed to the correct diagnosis, complete removal of soft dentin and the use of a well-sealing coronal restoration that could prevent microleakage. These results were comparable to Gruythuysen et al.13 who reported a high survival rate of IPT done in primary and permanent teeth of young patients. Survival was defined as teeth without clinical or radiologic signs or symptoms. The study findings were also in agreement to Sharma et al.14 who compared the effectiveness of disinfection of remaining carious dentin in deep cavities with PAD against calcium hydroxide and found successful outcome for the treated teeth at 45 days, 6 months, and 12 months with only one tooth evidence of apical periodontitis, which was considered failure.
Concerning the mean thickness of newly-formed dentin for both groups at different follow-up periods. There was no statistically significant difference between both groups at 2, 6, 9, and 12 months, with P values = 0.825, 0.146, 0.280, and 0.400, respectively. This might be due the absence of differences between both groups starting from baseline characteristics, case selection to the technique performed. Also, the sample used in this study might be considered as a factor for this finding.
The results were in accordance to Leye Benoist et al.2 which assessed the effectiveness of mineral trioxide aggregate compared to calcium hydroxide as an indirect pulp-capping material in molar and premolar teeth. The mean initial residual dentin thickness increased at 3 and 6 months in calcium hydroxide group. Also. Sultana et al.15 compared mineral trioxide aggregate and calcium hydroxide as capping materials. They showed that at 3 months, reparative dentin was formed in 17 teeth (of 25 teeth) in the calcium hydroxide group and at 6 and 12 months, 19 treated teeth showed evident of reparative dentin formation.
These results were opposite to de Pinheiro et al.16 who reported no increase or decrease in remaining dentin thickness after 12 months when compared with the baseline. This difference in findings could be justified by the presence of some difficulties such as precise measurement of lesion depth. The clinical carious lesion might be deeper than the assumed lesion’s radiographic appearance which makes the determination of the remaining dentin thickness clinically and radiographically difficult.17 The possible limitations of this study include the small sample size and the deficiency of clinical studies on the use of PAD.