Presence of Streptococcus mutans and lactobacilli in saliva and on enamel, glass ionomer cement, and composite resin surfaces

Abstract— The quantity of S. mutans , total streptococci, and lactobacilli on sound enamel surfaces and 1-yr-old glass ionomer cement and composite resin fillings with the cervical margins placed subgingivally was compared intraindividually. The amount of bacteria was compared to their number in saliva. The evaluation was done in a cross sectional study, where the patients continued to use their customary oral hygiene procedures and during a 14-day period of experimental plaque formation. The number of lactobacilli and S. mutans recovered from the test surfaces indicated that the critical salivary concentrations necessary for the isolation of S. mutans and lactobacilli from glass ionomer cement and composite resin surfaces are the same as for the enamel surfaces. The fluoride levels in plaque adjacent to glass ionomer cement will not become high enough to inhibit the accumulation of the investigated bacteria.     

Ribonuclease in Different Types of Saliva from Cystic Fibrosis Patients

ABSTRACT. The flow rate, the activity of ribonuclease (RNAase) and the concentration of protein were determined in whole saliva and in parotid and submandibular saliva from patients with cystic fibrosis (CF) and from healthy controls, both before and after stimulation of the salivary secretion. Lower flow rates were found in all types of saliva from CF-patients than in control saliva. Increased activity of RNAase was found in CF saliva, both before and after stimulation of the secretion. The concentration of protein was also increased, but to a lesser degree. No correlation was found between either RNAase activity or protein concentration and severity of the disease or age of the children. It is therefore unlikely that these disturbances are secondary to progression of the disease. Considerable variations in RNAase activity and protein concentration were observed, especially within the CF group, and therefore despite the significant increase in these variables in CF their estimation is of limited diagnostic value.     

SEM study of surface characteristics and marginal adaptation of anterior resin restorations after 3–4 years

SEM replica technique was. used to study surface characteristics and marginal adaptation of278 anterior resin fillings. 3-4 yr old. The fillings showed degradation of surfaces and margins with eroded areas and exposed macro- and microfiller particles. Cohesive failures were seen as chip fractures and marginal fractures parallel to the cavity margins. Microfiller resin fillings showed less rough surface characteristics than the conventional and hybrid composite resins in spite of a higher frequency of fillings with surface degradation. The microfiller resin fillings activated by visible light, in particular, showed relatively smooth surface characteristics with less surface degradation and less porosity. About 50% of the conventional and hybrid composite fillings showed marginal defects. The two chemically cured microfiller resin fillings showed marginal defects in 66% or 88%, whereas for the visible light cured microfiller resin fillings defects were observed in 44%.     

Porosity in posterior composite resins

Abstract – The percent pore area and the mean pore size were measured in specimens made of nine brands of composite resin restorative materials. The overall percent porosity ranged from 0.01 to 4.5%. The specimens for the study were prepared in two ways; by condensation or by pressure. Most of the materials, including all those chemically activated, showed more porosity in the condensed than in the pressure specimens. Reversed results emerged for two of the materials, and for another two, the specimens were similar in this respect. The mean pore sizes were smaller in the condensed than in the pressure specimens. Neither mean pore size nor total amount of porosities could be correlated to the curing method of the materials.     

A 3-year evaluation of Gluma and Gluma/Scotchbond for restoration of cervical erosions

Abstract – Gluma and Gluma/Scotchbond were used in cervical abrasion/erosion lesions mediating a bond between a resinous restorative material and dentin. The lesions were restored without acid etching of enamel and without use of an intermediary layer of an enamel bonding agent. 142 restorations were placed. The restorations were evaluated clinically using the USPHS-system at the baseline and every half year during a 3-yr period. After 36 months the Gluma and Gluma/Scotchbond restorations showed a 14.3% and 7.4%, cumulative loss of retention respectively. No secondary caries was observed during the evaluation period.