Previous studies have suggested that probiotic supplements in dairy products may affect the oral microbial ecology, but the effect in orthodontic patients has not previously been reported. The aim of the present study was to examine whether short-term consumption of fruit yogurt containing probiotic bifidobacteria would affect the levels of salivary mutans streptococci and lactobacilli in patients with fixed orthodontic appliances. A double-blind, randomized crossover study was performed and 24 healthy adolescents (12-16 years) undergoing orthodontic treatment were followed over four periods. During periods 2 and 4 (2 weeks each), the subjects ingested 200 g fruit yogurt containing Bifidobacterium animalis subsp. lactis DN-173010 (2 x 10(8) colony forming units/g) once daily or a control yogurt without viable bacteria. Periods 1 and 3 were run-in and wash-out periods of 1 and 6 weeks, respectively. Salivary mutans streptococci and lactobacilli were enumerated with chair-side kits before and after the yogurt consumption periods. Pre- and post-treatment values within each regimen were compared with a two-tailed marginal homogeneity test for categorical data. A statistically significant reduction of salivary mutans streptococci was recorded after probiotic yogurt consumption (P < 0.05), which was in contrast to the control yogurt. No significant alterations of the salivary lactobacilli counts were observed. Short-term daily consumption of fruit yogurt containing Bifidobacterium animalis subsp. lactis DN-173010 may reduce the levels of mutans streptococci in saliva during orthodontic treatment with fixed appliances.

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The purpose of this study was to evaluate enamel colour alteration of five different orthodontic bonding adhesives by means of digital measurements after exposure to photoageing in order to simulate discolouration of adhesives in vivo. Seventy-five non-carious premolars were randomly divided into five equal groups. The brackets were bonded with five different adhesives (Transbond XT, Eagle Bond, Light Bond, Blugloo, Unite) and subjected to artificial accelerated photoageing for 24 hours. The enamel surfaces were colourimetrically evaluated before bonding, following debonding and cleaning with a tungsten carbide bur, after polishing with Stainbuster, and after photoageing of the debonded enamel surface. The Commission Internationale de l'Eclairage(CIE) colour parameters (L*a*b*) were recorded and colour differences (DeltaE) were calculated. The results were statistically analyzed using the Kruskall-Wallis test. Further investigation among subgroups was performed using Dunn's multiple correlation test (P < 0.05). The clinical detection threshold for DeltaE value was set at 3.7 units. DeltaE values between the first and second measurements showed an increase in the Transbond XT, Eagle Bond, and Light Bond groups. The highest DeltaE value was 1.51 +/- 1.15 in the Transbond XT group. No clinically significant DeltaE value was observed. Colour changes of orthodontic bonding systems induced by photoageing cannot be clinically observed. Polishing with Stainbuster eliminates enamel surface roughness, which may improve light reflection.

ObjectiveThe purpose of this study was to quantitatively evaluate the cortical bone densities of the maxillary and mandibular alveolar processes in adults with different vertical facial types using cone-beam computed tomography (CBCT) images.MethodsCBCT images (n = 142) of adult patients (20-45 years) were classified into hypodivergent, normodivergent, and hyperdivergent groups on the basis of linear and angular S-N/Go-Me measurements. The cortical bone densities (in Hounsfield units) at maxillary and mandibular interdental sites from the distal aspect of the canine to the mesial aspect of the second molar were measured on the images.ResultsOn the maxillary buccal side, female subjects in the hyperdivergent group showed significantly decreased bone density, while in the posterior region, male subjects in the hyperdivergent group displayed significantly decreased bone density when compared with corresponding subjects in the other groups (p<0.001). Furthermore, the subjects in the hyperdivergent group had significantly lower bone densities on the mandibular buccal side than hypodivergent subjects. The maxillary palatal bone density did not differ significantly among groups, but female subjects showed significantly denser palatal cortical bone. No significant difference in bone density was found between the palatal and buccal sides in the maxillary premolar region. Overall, the palatal cortical bone was denser anteriorly and buccal cortical bone was denser posteriorly.ConclusionAdults with the hyperdivergent facial type tend to have less-dense buccal cortical bone in the maxillary and mandibular alveolar processes. Clinicians should be aware of the variability of cortical bone densities at mini-implant placement sites.

The aims of this study were to compare, in vitro, the shear bond strength (SBS) of stainless steel orthodontic brackets bonded to silver amalgam with the use of three different intermediate resins and two different adhesives, and to evaluate bond failure mode. Forty-five amalgam specimens were divided into three equal groups. In groups 1 and 2, the brackets were bonded with Unite (3M Unitek) using Reliance Metal Primer (RMP; Reliance Orthodontic Products) and Power Bond OLC (PB OLC; Ortho Organizers Inc.) as intermediate resins, respectively. In group 3, Resinomer and One-Step Plus (OS+; Bisco Inc.) were used. Thirty bovine teeth served as the controls to test bracket bonding to acid-etched enamel with Unite and Resinomer-OS+. After thermocycling from 10 to 50 degrees C 1000 times, all samples were tested for SBS. Bond failure sites were classified using a modified adhesive remnant index (ARI) system. Data were analyzed with one-way analysis of variance, post hoc Tukey multiple comparison and chi-square tests. The results showed that the mean SBS to amalgam surfaces were significantly lower than those to etched bovine enamel (P<0.001). There were no statistically significant differences in mean SBS between the amalgam bonding groups (P>0.05). For the ARI, significant differences were found between the amalgam- and enamel-bonding groups (P<0.001). The mean SBS of stainless steel orthodontic brackets bonded to amalgam surfaces with RMP, PB OLC, OS+ intermediate resins and Unite and Resinomer adhesives was significantly lower than to etched bovine enamel. Bond failure occurred at the amalgam-adhesive interface regardless of the adhesive system and without damage to the amalgam restoration.