Evaluation of Probiotic Effects of Lactobacilli on Mutans Streptococci: An In Vitro Study

AIM

The aim of the present study is to evaluate the probiotic effect of Lactobacillus acidophilus and Lactobacillus rhamnosus on clinical isolates of Mutans Streptococci (MS) and antibiotic susceptibility of these strains to commonly used antibiotics in dentistry.

MATERIALS AND METHODS

Plaque samples from permanent first molars were collected and transferred aseptically onto Mitis-Salivarius agar and incubated at 37°C for 24 hours in the presence of 5-10% CO₂. Mutans streptococci colonies were identified biochemically using Hi-Strep identification kit. The inhibitory activity of the clinical strains of MS on Lactobacilli was investigated using agar-overlay interference technique. Positive inhibition was appreciated as a clear zone around the Lactobacilli. Disk diffusion assay was done as described by CLSI M100-S25 for antibiotic susceptibility. The zone of growth inhibition caused by Lactobacilli and antibiotics on MS clinical strains was measured directly using a vernier caliper. Statistical analysis was done using independent t-test.

RESULTS

Mutans streptococci exhibited positive inhibition with both the probiotic strains and L. acidophilus showed more zones of inhibition than L. rhamnosus. Antibiotic susceptibility of clinical strains of MS showed sensitivity to penicillin and vancomycin, however, tetracycline and erythromycin showed very few resistant strains. The highest zone of inhibition was shown by cephalothin followed by penicillin, tetracycline, ciprofloxacin, erythromycin, and vancomycin.

CONCLUSION

L. rhamnosus and L. acidophilus have strong inhibitory effects on clinical strains of MS. Lactobacillus acidophilus showed a higher zone of inhibition. All the clinical strains of MS were sensitive to penicillin and vancomycin. The highest zone of inhibition was shown by cephalothin.

CLINICAL SIGNIFICANCE

Dental caries remains silent epidemic and increasing antibiotic resistance is another major challenge that threatens the world. Newer methods such as whole-bacteria replacement therapy using probiotics for decreasing harmful oral pathogens and reducing the intake of antibiotics must be explored. More researches to promote use of probiotics should be initiated due to its possible preventive and health maintenance benefits providing an end to new cavities and antibiotic resistance.

Effects of different dentinal drying methods on the adhesion of glass ionomer restorations to primary teeth

BACKGROUND

Glass ionomer cements that form an inevitable part of pediatric restorative dentistry are inherently sensitive to moisture. The influence of different drying techniques on the shear bond strength of glass ionomer cements to primary teeth dentin has not been established.

AIMS

The purpose of the study was to evaluate the effects of different drying methods for different drying time periods on the shear bond strength of GC Fuji IX to primary tooth dentine.

SUBJECTS AND METHODS

A total of 135 caries-free primary teeth were selected and ground to a flat dentinal surface. Specimens were randomly divided into three groups - air dry, blot dry, and suction dry of 45 specimens each. Of these, 15 specimens each were dried for 2 s, 5 s, and 10 s. GC Fuji IX was condensed into Teflon molds, and the specimens were subjected to shear bond strength testing.

RESULTS

The mean shear bond strength values for the different time intervals were analyzed with analysis of variance test. In the air-dry group, the maximum shear bond strength values were obtained when the specimens were dried for 5 s and the least when dried for 2 s (P = 0.00). In the blot-dry and suction-dry groups, the highest values were obtained when the specimens were dried for 10 s and least for 2 s (P = 0.039 and 0.000, respectively).

CONCLUSIONS

Among the three drying methods employed in the study, the maximum shear bond strength of the glass ionomer restoration was observed in the air-dry group.

Blandin and Nuhn mucocele in a pediatric patient

Oral mucoceles are benign lesions that may appear in any location on the mucosal surfaces of the oral cavity where underlying minor salivary glands are found. The lower lip is the most frequently affected and the most widely reported location. Mucoceles involving the glands of Blandin and Nuhn are infrequent and constitute only about 1.9%-10.3% of the reported cases. Superficial mucoceles are a rare subtype of the Blandin and Nuhn mucoceles and are found only in 4.3%-10% of the mucocele excisions. The purpose of this report is to present a case of a superficial mucocele in the ventral surface of the tongue in a 7-year-old child. The lesion was treated with excisional biopsy.

Surface micromorphological changes of glass ionomer following application of 1.23% acidulated phosphate fluoride: a scanning electron microscope study

OBJECTIVES

The purpose of this study was to evaluate the surface micromorphological changes of conventional glass ionomer cement (GIC) (Fuji II, GC Corporation, Tokyo, Japan) and high strength, high viscosity GIC (Fuji IX GP, GC Corporation) subjected to 1.23% acidulated phosphate fluoride (APF) gel for 4 min. It also evaluated the surface micromorphological changes that occurred in these materials when they were coated with a layer of glass ionomer varnish prior to the application of 1.23% APF gel.

MATERIALS AND METHODS

A total of 60 uniform glass ionomer cylinders were prepared (30 of each Fuji II and Fuji IX) and stored in distilled water for 48 h, following which they were divided into six groups depending on the surface treatment. Group 1: Fuji II alone, Group 2: Fuji IX alone, Group 3: Fuji II + 1.23% APF gel for 4 min, Group 4: Fuji IX + 1.23% APF gel for 4 min, Group 5: Fuji II + varnish + 1.23% APF gel for 4 min, and Group 6: Fuji IX + varnish + 1.23% APF gel for 4 min. After the required surface treatment had been done, the specimens were mounted, coated, and evaluated under scanning electron microscope.

STATISTICAL ANALYSIS

Kruskal-Wallis test applied to compare the level of degradation among the groups subjected to treatment was highly significant (P < 0.001). Mann-Whitney test was applied to test the association between glass ionomer varnish and level of surface degradation and was also statistically significant (P = 0.001).

RESULTS

The results indicated that APF gel etched the surface of both Fuji II and Fuji IX. However, Fuji IX showed to possess better resistance to the erosive effect of APF than Fuji II. It was also observed that application of glass ionomer varnish prior to APF gel application protected the glass ionomer from the erosive effect of APF gel.

CONCLUSION

APF gel caused erosive wear of the GICs esp. Fuji II. Hence, it is advisable to avoid the use of APF containing preparations for regular home use especially in children having glass ionomer restoration. If APF gel is indicated or preferred for professional application, it is recommended to apply glass ionomer varnish on the restored teeth prior to the APF gel application.

Desmoplastic fibroblastoma (collagenous fibroma) in the oral cavity

Desmoplastic fibroblastoma (DF) also known as collagenous fibroma (CF) is a rare benign soft tissue tumor that occurs in varied locations in the body. Very few cases of DF have been reported in the oral cavity. We report a case of DF in an 8-year-old boy presented as a slow-growing mass in the buccal mucosa since 6 months. Histopathology, special staining and immunohistochemistry studies suggested a diagnosis of CF. As per our knowledge of the current literature this is the seventh case reported in the oral cavity and the first report in a child.

A comparative study of salivary buffering capacity, flow rate, resting pH, and salivary Immunoglobulin A in children with rampant caries and caries-resistant children

PURPOSE

This study was conducted to identify various factors in the development of rampant type of dental caries in South Kerala children, other than high sucrose intake and poor oral hygiene. This was done by comparing the salivary buffering capacity(BC), flow-rate(FR), resting pH and salivary immunoglobulin-A(s-IgA) levels in children who are caries resistant(CR) and who have rampant dental caries.

MATERIALS AND METHODS

Two study groups, a rampant caries group(RC) with more than five active caries lesions in the early stages and a CR with no caries lesions were selected based on a specific criteria. Unstimulated whole mixed saliva was collected directly from the floor of the mouth for a period of 10 min and the FR was calculated. Resting pH of saliva was measured using color coded pH paper. BC was measured by calculating the amount of citric acid of pH2.5, required to lower the initial pH of saliva down to 3. s-IgA levels were also estimated by immunoturbidometric method after forming a precipitate of s-IgA with specific anti-IgA antibodies.

RESULT

The salivary BC, FRs, pH and s-IgA levels were significantly lower in the RC group when compared to the CR group.

CONCLUSION

This study showed that salivary BC, flow-rate, resting pH and levels of s-IgA in saliva are risk factors in the development of RC in children.

Salivary calculus: an insight into its pathogenesis--a case report of parotid sialolith in a 9 year old child

The occurrence of sialolithiasis in children is uncommon, while parotid sialoliths are rare. A case of parotid sialolith in a 9 year old child is reported.