This randomized clinical trial aimed to assess the efficacy of sealing occlusal carious lesions in permanent teeth. The sample consisted of 54 occlusal carious lesions in permanent molars and premolars of 49 patients aged 8-43 years (median: 19 years). The inclusion criteria comprised the presence of a cavity with no access allowing biofilm control. The maximum depth of the lesion was the middle third of the dentin thickness, as assessed by bitewing radiography. The teeth were randomly assigned to sealant treatment (n = 28) or restorative treatment (n = 26). Clinical and radiographic examinations were performed after 1 year and after 3-4 years. The outcomes depended on the clinical performance of the sealant/restoration and the control of caries progression observed radiographically. Survival analysis was performed to assess success rates. Over the 3-4 years of monitoring, 2 sealants were totally lost, 1 needed repair, and 1 showed caries progression, totaling 4 failures in the sealant group. In the restoration group, 1 failure was observed (in need of repair). The success rates were 76% and 94% in the sealant and the restoration groups, respectively (p > 0.05). The sealing of occlusal carious lesions in permanent teeth succeeded in controlling caries over a 3-4-year period. However, sealed carious lesions require patient compliance in attending regular follow-ups to control the occurrence of clinical failures of the sealants.

Aim:  To determine the genetic diversity and possible origin of Lactobacillus paracasei found in the oral biofilm. Methods and Results:  Lactobacilli were isolated from a biofilm model, formed in situ prior to and during a period of exposure to 20% sucrose solution (28 days), using Rogosa Agar. The lactobacillus colonies were randomly selected (n = 222) and subcultured. The isolates were identified using pheS or rpoA gene sequence analysis. Lactobacilli identified as Lact. paracasei (n = 75) were subjected to multilocus sequencing typing (MLST) analysis by determining partial sequences of seven housekeeping genes fusA, ileS, lepA, leuS, pyrG, recA and recG. An increase recovery of lactobacilli after sucrose phase compared with nonsucrose period was observed (31 prior to and 191 following a sucrose exposure period). Seven subjects harboured Lact. paracasei and these represented 14 sequence types (ST). Comparison of the STs showed that unrelated subjects may harbour the same ST and that individuals harbour multiple STs. Three subjects harboured STs previously isolated from dairy products. Conclusion:  The present data supports the hypothesis that oral lactobacilli may be of exogenous origin. Significance and Impact of the Study:  The study allow us to gain insight into the genetic diversity of Lact. paracasei in oral biofilm.

The aim of this study was to evaluate the effect of a commercial lactose-containing stevioside sweetener on biofilm acidogenicity in vivo. Nine volunteers refrained from brushing their teeth for 3 days in five phases. On the 4th day of each phase, the pH of the biofilm was measured by the "Strip method". Interproximal plaque pH was measured before and up to 60 minutes after a 10 mL mouthrinse for 1 minute with the test solutions: I -sweetener with 93% lactose and 7% stevioside; II -sweetener with 6.8% saccharin, 13.6% cyclamate, and 0.82% stevioside; III -18% sucrose solution (positive control); IV -mineral water (negative control); and V-93% lactose solution. The results revealed that the most pronounced pH fall was found with sucrose (positive control), followed by the 93% lactose solution, the sweetener with lactose + stevioside, the sweetener with saccharin + cyclamate + stevioside, and finally water (negative control). According to the area under the curve, the two sweeteners containing stevioside were significantly different, and the sweetener with lactose + stevioside was significantly different from water but not from sucrose. The critical pH for dentin demineralization (pH ≤ 6.5) was reached by all volunteers after rinsing with sucrose solution, lactose solution, and the stevioside + lactose sweetener. Analysis of the data suggests that lactose-containing stevioside sweeteners may be cariogenic, especially to dentin.