Effect of Periodontal Pathogens on Total Bone Volume Fraction: A Phenotypic Study.

Studies have shown that periodontal pathogens can enter the bloodstream, causing a series of reactions that can lead to a variety of systemic diseases. Epidemiological investigations also found a tight correlation between periodontitis (PD) and osteoporosis. This study aimed to further explore the effect of periodontal pathogens on bone volume fraction like bone tissue and mass, and explain the relationship between PD and osteoporosis. Sprague Dawley rats (female, 16 weeks old) were divided into the wild-type (WT) control group (n=9) and PD group (n=9). After eight weeks, periodontal tissues and ligatures, the fourth lumbar vertebra, the femur, the tibia, and blood were extracted and analyzed by micro-computed tomography (micro-CT), hematoxylin and eosin (H&E) staining, tartrate-resistant acid phosphatase (TRAP) staining, polymerase chain reaction (PCR), and enzyme-linked immunoassay (ELISA), respectively. We found that the bone mass of the lumbar vertebra, femur, and tibia was decreased in the PD group. The number of osteoclasts was higher in bone tissue in the PD group than in the WT group (P<0.05). The levels of inflammatory mediators and type I collagen C-terminal peptide (CTX-1) were higher in the PD group than in the WT group (P<0.05), although no significant difference in bone glutamic acid protein (BGP) levels was observed (P>0.05). In addition, we detected several periodontal pathogens, such as Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, and Fusobacterium nucleatum, in blood samples from rats in the PD group. These findings suggest that periodontal pathogens can enter the blood circulation from periodontal tissue, promote a systemic inflammation response, and subsequently reduce systemic bone density.

Maxillary anterior teeth dimensions and proportions in a central mainland chinese population.

OBJECTIVES: To obtain maxillary anterior tooth dimension and proportion values for the Central Chinese population and to evaluate the existence of sexual dimorphism, any consistent relationships between the tooth ratios, and the presence of golden proportions. METHODS: Tooth dimensions and proportions of six maxillary anterior teeth were recorded on gypsum casts obtained from 147 subjects (82 women and 65 men). Of these, 115 casts were digitally photographed in a standardised manner and apparent width values for six maxillary anterior teeth were recorded for golden proportion analysis. Existence of sexual dimorphism, any consistent width/height ratio and golden proportions were statistically analysed. One-sample t-test, two-sample t-test, and paired t-test were used to analyse the data. RESULTS: There were no significant differences between measurements on the right and left side. Sexual dimorphism existed for various tooth dimensions. There was no statistically significant difference for width/height ratios between the two genders for central incisor and lateral incisor. However, canines showed a statistically significant difference. The golden proportion guideline was not applicable for this population. CONCLUSION: The maxillary anterior teeth dimensions were significantly greater for men than women; however, the mean difference was small (< 0.2 mm) and may not be clinically significant. The golden proportion, or any recurring anterior teeth proportions, was not found for the population. There was a significant difference in width/height ratio of canines between the genders, confirming its greatest gender-based morphological difference.