Introduction. Improvement of the quality of dental care is necessary for efficient prevention of oral diseases. The aim of this study was to analyze: the efficiency of the recommended work quality parameters in the Dental Health Care Service of the Health Center Zemun in 2014 and 2015; compare 7-and 12-year-olds in terms of having all healthy teeth and topical application of fluoride; presence of orthodontic anomalies in 12-and 14-year-olds, and assess the caries index (decayed-missing-filled teeth) in 12-year-old children. Material and Methods. The retrospective study included 7-, 12-, 14-, and 18-yearolds and assessed their oral health in 2014 (n = 4.317) and 2015 (n = 6.575). Results. A higher percentage of examinees kept their dental appointments in 2015 than in 2014 (82% and 60%, respectively). Out of 3.723 seven-year-olds, 36.6% had all healthy teeth, as well as 43.69% out of 3.170 of 12-year-olds. Out of 3.723 seven-year-olds, 65.26% had topical application of fluoride, as well as 78.73% out of 3.170 of twelve-year-olds. High percentages of orthodontic anomalies were found in both fourteen and eighteen-year-olds in 2015 (p<0.05). The average decayed-missing-filled teeth index in twelve-year-olds was 1.30 in 2014 and 1.68 in 2015. Conclusion. A higher percentage of all healthy teeth, and of topical application of fluoride in twelveyear-olds compared to the seven-year-olds, indicates that seven-yearolds keep their dental appointments more regularly, and consequently the prevention of oral diseases is more successful. Since the presence of orthodontic anomalies is high in both fourteen and eighteenyear-olds, and fewer children of both age groups respond to regular dental checkups, an intensified prevention of oral diseases is necessary in children.