Er,Cr:YSGG Laser Versus Conventional Preparation for Minimally Invasive Caries Removal

Er,Cr:YSGG Laser Versus Conventional Preparation for Minimally Invasive Caries Removal: Clinical PCR Study of Streptococcus Mutans and Lactobacillus Spp. in Dentin Reference to the Main Project (Sub-study of Strategic Research and Innovation Program for Development of Medical University - Sofia, BG-RRP-2.004-0004-C01)

This study compared two standard methods for minimally invasive caries removal in children: conventional mechanical excavation and Er,Cr:YSGG laser preparation. The study aimed to evaluate the reduction of Streptococcus mutans and Lactobacillus spp. in dentin using PCR analysis. All procedures were performed as part of routine dental care, and written informed consent was obtained from parents or legal guardians.

This comparative clinical study included 32 carious lesions in permanent molars and premolars from children aged 8-15 years. Lesions were randomly assigned to either conventional mechanical preparation (n=17) or Er,Cr:YSGG laser preparation (n=15). Samples of carious and affected dentin were collected before and after preparation, and bacterial DNA was analyzed using PCR for S. mutans and Lactobacillus spp. The study followed ethical approval from the Ethics Committee of the Medical University of Sofia (protocol № 14/28.09.2023), and written informed consent was obtained from all parents/guardians. The study was conducted entirely within the framework of routine dental treatment, with standard, clinically approved methods applied for all participants. Statistical analysis included descriptive statistics, Wilcoxon signed-rank test for within-group comparisons, and Mann-Whitney U test for between-group comparisons.

Inclusion Criteria:

• Lesions located in the inner half of dentin, with a visible cavity or extensive dentin lesion (≥1 mm, measured with a periodontal graded probe)
• Negative response to percussion
• Absence of pulpal symptoms or spontaneous/night pain
• Permanent molars or premolars fully erupted

Exclusion Criteria:

• Lesions involving less than half of the dentin or without a visible cavity
• Teeth with significant crown destruction (ICDAS 06)
• Positive response to percussion, pulpal symptoms, spontaneous/night pain
• Teeth with periapical changes