Background Dental caries initiates with non-cavitated enamel lesions as the first stage. The cariogenic potential of N-Acetylcysteine (NAC) may be due to its usage frequency and form. This study aimed to evaluate the impact of exposure time of NAC on initial enamel caries-like lesions in primary teeth by assessing the morphological alteration using a scanning electron microscope (SEM) and mineral content using energy dispersive x-ray spectroscopy (EDX). Methods Forty primary incisor teeth were randomly divided into 4 groups S, S1, S2, and S3 (10 specimens/group). Teeth crowns were cut from their roots and inserted into an acrylic mold with its buccal surface directed upward. Centrally isolated enamel window (2 × 2 mm) on the tooth was done. Ten specimens were selected to evaluate normal enamel while the remaining thirty specimens were immersed in demineralizing solution for 96 h to produce enamel caries-like lesions. PH cycling was performed by immersing each tooth sample in 20 mL of demineralizing solution for 3 h then, preserved for the remaining day hours in 10 ml of artificial saliva interspersed with treatments applications with 10 ml NAC for 10 min twice a day for one- or three-months different treatment modalities. Thermocycling was done for all specimens then they were subjected to SEM and EDX analysis. ANOVA and Bonferroni post hoc tests were utilized in data analysis. Results In teeth treated by NAC for 3 months (group-S3), SEM images showed severe loss of enamel architecture with large NAC deposits detected. A meaningful difference was observed among different groups concerning calcium, phosphorus, fluoride, ca/P ratio, carbon, nitrogen, and oxygen contents (P < 0.05). Conclusion NAC had a detrimental impact on enamel caries-like lesions in human primary teeth.

Background: To assess & compare clinical & radiographic effects of Hyaluronic acid (HA) versus formocresol (FC) as pulpotomy medication in primary molars. Materials & Methods: 20 children in age group 4-7 years have bilateral primary molars which need pulpotomy treatment due to deep caries. children divided into two groups, group I included 20 molars treated with HA & group II included 20 molars treated by FC. Patients were recalled after 3, 6, and 12 months for clinical and radiographical evaluation.Results: Clinically all cases showed no signs of pain, gingival swelling, or mobility in both HA, FC group except at 12 months. Radiographically, both HA, FC groups revealed no internal resorption at 3, 6 months while at 12 months only one case of FC group, three cases of HA group showed internal resorption. FC group revealed increase in the PDL space at 3, 6 and 12-months while HA group showed decrease in PDL space at 3 and 6 months then slight increase occurred at 12 months. FC group revealed furcation radiolucency increase at 3, 6 and 12 months while HA group showed slight decrease in bone radio-density at 3 months then an increase in bone radiodensity at 6 months followed by a decrease at 12 months. Conclusion:Clinical and radiographic success rates of HA is comparable to FC for primary molars over 12 month follow-up period.Recommendation: Further clinical studies with long time evaluation periods should be done to investigate HA effects on primary pulp tissues.

Background Cameriere’s original formula based on open apex measurements is a reliable, clinically applicable method for dental age estimation in different populations children. Dental development may differ between Egyptian children and other ethnic populations which may affect dental age accuracy using Cameriere’s formula. Aim Firstly, to verify Cameriere’s original formula on large Egyptian children sample, secondly, to develop an Egyptian-specific formula based on Cameriere’s method. Material and methods A prospective cross-sectional study of 762 good quality Orthopantomograms (OPGs) of 5–15 aged healthy Egyptian children selected from Nile Delta governorates between August 2020 and December 2021. Chronological age (CA) was calculated by subtracting birth date from radiograph date. OPGs were analyzed for N0, S, Xi morphologic variables using Sidexis program after that dental age was calculated using Cameriere’s formula then compared to CA. Multiple linear regression model was used to adapt Cameriere’s formula to construct an Egyptian formula. The same sample was used to verify the new formula accuracy. Results A total of 1093 OPGs were collected; 762 OPGs which met inclusion criteria were analyzed. Cameriere’s original formula revealed − 0.59- and − 0.53-year underestimation of females and males dental age (DA) respectively (p < 0.001). Regression analysis using the morphologic variables showed that X4, X7, N0 contributed significantly to CA yielding Egyptian-specific formula. New formula showed − 0.12-year male underestimation and 0.1-year female overestimation (p > 0.05). Conclusion Egyptian formula was more accurate than Cameriere’s formula in Egyptian children. Clinical relevance Egyptian-specific formula decreases the gap between CA and DA, so a relative approximate age is obtained that helps proper diagnosis and treatment planning for orthodontic and pediatric dentistry problems.