Changes in the supragingival microbiota surrounding brackets of upper central incisors during orthodontic treatment.

OBJECTIVE: The aim of this study was to determine how fixed orthodontic appliances affect microbiota of supragingival plaque over 5 months. MATERIALS AND METHODS: Twenty individuals of Scandinavian origin, aged 10-16 years, were included. All subjects were fitted with fixed orthodontic appliances in both the maxillary and mandibular tooth arches. Pooled supragingival plaque samples from the labial surface of the two maxillary central incisors were collected before bonding (T1) and afterwards at 4 weeks (T2), 3 months (T3) and 5 months (T4). The plaque index (PI) was recorded for each sampling. The gingival status was documented at T1 and T4 by using clinical photographs. Plaque microbiota was identified using the Human Oral Microbe Identification Microarray (HOMIM). RESULTS: Increased plaque levels were recorded after bonding, however the increase was not significant. The prevalence of gingivitis at the maxillary central incisors increased from 25% at T1 to 74% at T4. No significant changes of the plaque microbiota from the sample area were detected during the 5-month period. Trends toward a microbiota containing more periodontitis- and caries-associated bacteria were detected. CONCLUSIONS: Although trends toward a microbiota containing more periodontitis- and caries-associated bacteria were detected, the changes were not severe enough to be significant. Treatment with fixed orthodontics does not necessarily shift the microbiota to a more pathogenic composition.

Clinical color intensity of white spot lesions might be a better predictor of enamel demineralization depth than traditional clinical grading.

INTRODUCTION: The aims of this study were to calculate the volume of white spot lesions by using microcomputed tomography and to determine which clinical attribute of the white spot lesion could better predict its volume: the clinically visible white spot lesion surface area or its color intensity. METHODS: White spot lesions were induced in 8 patients in vivo on 23 healthy premolars destined for extraction during orthodontic treatment by using specially designed plaque-retaining orthodontic bands. After 7 weeks, the premolars were extracted. After extraction, the resulting white spot lesions were photographed and clinically graded. The teeth were analyzed with microcomputed tomography. RESULTS: After 7 weeks, 70% of the teeth developed clinical white spot lesions. Clinically, the size of the lesions varied from minor to severe. Their volumes varied from 0 to 1.2931 mm(3). The traditional grades for white spot lesions correlated significantly with color intensity. A significant correlation was found between white spot lesion color intensity and lesion volume. This correlation was found to be better than that between the white spot lesion clinical score and lesion volume. CONCLUSIONS: Our results indicate that white spot lesion color intensity might predict the depth of enamel demineralization as well as or better than traditional white spot lesion scoring. Therefore, the dentist could use this information when planning treatment for white spot lesions.

Microbial community succession on developing lesions on human enamel.

BACKGROUND: Dental caries is one of the most common diseases in the world. However, our understanding of how the microbial community composition changes in vivo as caries develops is lacking. OBJECTIVE: An in vivo model was used in a longitudinal cohort study to investigate shifts in the microbial community composition associated with the development of enamel caries. DESIGN: White spot lesions were generated in vivo on human teeth predetermined to be extracted for orthodontic reasons. The bacterial microbiota on sound enamel and on developing carious lesions were identified using the Human Oral Microbe Identification Microarray (HOMIM), which permits the detection of about 300 of the approximate 600 predominant bacterial species in the oral cavity. RESULTS: After only seven weeks, 75% of targeted teeth developed white spot lesions (8 individuals, 16 teeth). The microbial community composition of the plaque over white spot lesions differed significantly as compared to sound enamel. Twenty-five bacterial taxa, including Streptococcusmutans, Atopobiumparvulum, Dialisterinvisus, and species of Prevotella and Scardovia, were significantly associated with initial enamel lesions. In contrast, 14 bacterial taxa, including species of Fusobacterium, Campylobacter, Kingella, and Capnocytophaga, were significantly associated with sound enamel. CONCLUSIONS: The bacterial community composition associated with the progression of enamel lesions is specific and much more complex than previously believed. This investigation represents one of the first longitudinally-derived studies for caries progression and supports microbial data from previous cross-sectional studies on the development of the disease. Thus, the in vivo experiments of generating lesions on teeth destined for extraction in conjunction with HOMIM analyses represent a valid model to study succession of supragingival microbial communities associated with caries development and to study efficacy of prophylactic and restorative treatments.

Age-related changes of the soft tissue profile from the second to the fourth decades of life.

OBJECTIVE: To describe the age-related changes of the soft tissue facial profile from the second to fourth decades of life. MATERIALS AND METHODS: Cephalograms from the same subjects in their 20s, 30s, and 40s were analyzed. A coordinate system analysis based on stable landmarks is used. A line connecting Walker's point (W) and sphenoethmoidal (SE) created the x-axis. Walker's point was origin. Depending on data distribution, landmark displacements from T1 to T2, from T2 to T3, and from T1 to T3 were analyzed using the paired t-test or the Wilcoxon test for zero expected change versus a two-sided alternative. For each landmark the mean, standard deviation, P value, and lower and higher 95% confidence intervals were calculated. RESULTS: During T2-T1, for males, the whole profile was displaced anteriorly and slightly superiorly, and for females, the lower facial profile was displaced in a posterior and inferior direction. Greater changes occurred in the female profile than the male profile. During T3-T2, the female profile changed slightly while the male profile underwent great changes: the upper facial profile was displaced anteriorly, and the lower profile was displaced posteriorly. The whole profile was displaced in the inferior direction. CONCLUSIONS: Significant changes occurred in the soft tissue facial profile from the second to fourth decades. Aging of the male facial profile began 10 years later than for females; however, when the changes did occur, they were of greater magnitude. The upper facial profile was displaced in the anterior direction and the whole profile was displaced inferiorly for both sexes.