Periodontal diseases are complex inflammatory diseases and affect up to 20% of the worldwide population. An unbalanced reaction of the immune system toward microbial pathogens is considered as the key factor in the development of periodontitis. Defensins have a strong antimicrobial function and are important contributors of the immune system toward maintaining health. Here, we present the first systematic association study of DEFB1. Using a haplotype-tagging single nucleotide polymorphism (SNP) approach, including described promoter SNPs of DEFB1, we investigated the associations of the selected variants in a large population (N ¼ 1337 cases and 2887 ethnically matched controls). The 3 0 untranslated region SNP, rs1047031, showed the most significant association signal for homozygous carriers of the rare A allele (P ¼ 0.002) with an increased genetic risk of 1.3 (95% confidence interval: 1.11-1.57). The association was consistent with the specific periodontitis forms: chronic periodontitis (odds ratio ¼ 2.2 (95% confidence interval: 1.16-4.35), P ¼ 0.02), and aggressive periodontitis (odds ratio ¼ 1.3 (95% confidence interval 1.04-1.68), P ¼ 0.02). Sequencing of regulatory and exonic regions of DEFB1 identified no other associated variant, pointing toward rs1047031 as likely being the causative variant. Prediction of microRNA targets identified a potential microRNA-binding site at the position of rs1047031.

Although it was found in previous studies that there is no significant difference between bond strength of acid etched enamel and Er,Cr:YSGG laser etched enamel, the dye penetration rate differs. On the basis of the results of our study, the additional use of etching after Er,Cr:YSGG laser preparation is recommended as it is used in the classical cavity preparation technique.

The aim of the present study was to establish whether cavity preparation by means of an erbium laser with efficient water cooling is capable of reducing the susceptibility of the prepared dental enamel to demineralization and thus of achieving a potential caries-protective effect in the region of cavity margins. To this end, cavities limited to the enamel were prepared in the crowns of 10 teeth each using an Er:YAG (λ = 2,940 nm) and an Er,Cr:YSGG laser (λ = 2,780 nm). A control cavity prepared conventionally with a diamond drill in the same occlusal zone was assigned to each of these cavities. The specimens were then subjected to a pH-cycling caries model. Analysis was performed by quantitatively measuring the demineralization front under a polarized-light microscope. The results of the study showed that enamel cavities prepared with the erbium lasers used display a statistically significant acceleration of demineralization compared to conventionally prepared cavities (p < 0.01). The Er:YAG laser cavities revealed demineralization to a depth of 133.9 (SD 25.7) µm, while the value observed with the Er,Cr:YSGG laser was 133.8 (SD 25.8) µm. The depth of demineralization in the control groups was only 77.4 (SD 13.8) µm and 79.3 (SD 37.6) µm. No difference could be found between the two lasers (p = 0.98). Based on these in vitro tests, it cannot be assumed that use of the erbium laser for cavity preparation offers any advantages in terms of resistance to secondary caries in clinical practice.

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Polymorphisms in the interleukin-1 (IL1) gene have been suggested to influence transcription of IL1A (interleukin-1alpha) and IL1B (interleukin-1beta) and thereby the pathophysiology of periodontitis. This case-control association study on 415 northern European Caucasian patients with aggressive periodontitis (AgP) and 874 healthy controls was conducted to examine 10 single-nucleotide polymorphisms (SNPs) in the genes of the IL1 cluster for association with IL1A, IL1B, CKAP2L (cytoskeleton-associated protein 2-like), and IL1RN (IL-1 receptor antagonist). The results do not support an association between variants in the IL1 gene cluster and AgP. This case-control study had at least 95% power to detect genuine associations with variants carrying relative risks of at least 1.5 for heterozygous carriers and 2.25 for homozygous carriers. Previous reports of an association between IL1 promoter SNPs and periodontitis might reflect subpopulation effects and have to be interpreted with care.