Veena R L, Nagarathna C
Department of Pedodontics and Preventive Dentistry, Rajarajeswari Dental College and Hospital, Bengaluru, Karnataka, India.
Indian J Dent Res. 2020 Jan-Feb;31(1):73-79. doi: 10.4103/ijdr.IJDR_432_18.
The aciduric mutans streptococci (MS) group, including Streptococcus mutans (SM) and Streptococcus sobrinus (SS), is highly cariogenic. Relationship between increments in dental caries and the presence of these species is not yet clarified. It is of great importance to separately determine the presence of these two species for understanding their role in dental caries, accurate prediction, and effective prevention. Hence, this study was undertaken to detect the presence of SM and SS in plaque samples of caries-free (CF), early childhood caries (ECC), and severe early childhood caries (S-ECC) and also to compare the possible relationship between these species with the occurrence of ECC.
In all, 120 healthy children between 3 and 6 years of age were randomly allocated into three groups: Group A (n = 40) CF, Group B (n = 40) ECC, and Group C (n = 40) S-ECC. Plaque samples were collected from all approximal surface and gingivobuccal surfaces of teeth using a sterile universal scaler and dmft/dmfs scores were taken. The presence of SM and SS was evaluated using real-time polymerase chain reaction.
The presence of SM in CF, ECC, and S-ECC was 10.0%, 27.5%, and 42.5%, respectively, and SS was 5.0%, 40.0%, and 47.5% in CF, ECC, and S-ECC, respectively. Comparison of mean relative quantification (RQ) values of SM between three study groups showed significant results between CF and S-ECC at P value 0.003. Comparison of mean RQ values of SS showed significant results between CF to ECC and CF to S-ECC at P value <0.001. This study showed significant results between the mean dmft/dmfs scores in three study groups and the presence of high levels of SM and SS in ECC and S-ECC groups. However, the study showed weak positive correlation between dmfs scores and both SM and SS species in ECC and S-ECC.
Higher levels of SS were more closely related to the caries-active lesions leading to severity of dental disease, that is, both in ECC and S-ECC. There was significant difference between mean dmft/dmfs scores in three study groups and it also showed positive correlation between dmfs scores and SM and SS colonization in ECC and S-ECC status.
嗜酸乳杆菌变形链球菌（MS）组，包括变形链球菌（SM）和远缘链球菌（SS），具有高度致龋性。龋齿增量与这些菌种的存在之间的关系尚未明确。分别确定这两种菌种的存在对于了解它们在龋齿中的作用、准确预测和有效预防至关重要。因此，本研究旨在检测无龋（CF）、幼儿龋齿（ECC）和重度幼儿龋齿（S-ECC）菌斑样本中SM和SS的存在情况，并比较这些菌种与ECC发生之间的可能关系。
总共120名3至6岁的健康儿童被随机分为三组：A组（n = 40）CF，B组（n = 40）ECC，C组（n = 40）S-ECC。使用无菌通用洁治器从所有牙齿的邻面和龈颊面采集菌斑样本，并记录dmft/dmfs分数。使用实时聚合酶链反应评估SM和SS的存在情况。
CF、ECC和S-ECC中SM的存在率分别为10.0%、27.5%和42.5%，CF、ECC和S-ECC中SS的存在率分别为5.0%、40.0%和47.5%。三个研究组之间SM平均相对定量（RQ）值的比较显示CF和S-ECC之间结果显著，P值为0.003。SS平均RQ值的比较显示CF与ECC之间以及CF与S-ECC之间结果显著，P值<0.001。本研究显示三个研究组的平均dmft/dmfs分数与ECC和S-ECC组中高水平的SM和SS存在之间存在显著结果。然而，该研究显示ECC和S-ECC中dmfs分数与SM和SS菌种之间存在弱正相关。
较高水平的SS与导致牙齿疾病严重程度的龋病活跃病变关系更为密切，即在ECC和S-ECC中均如此。三个研究组的平均dmft/dmfs分数之间存在显著差异，并且在ECC和S-ECC状态下，dmfs分数与SM和SS定植之间也显示出正相关。
