Bettina Dannewitz

Relationship between microtensile bond strength and nanoleakage at the composite-dentin interface

OBJECTIVES This study evaluated the relationship between microtensile bond strength (microTBS) and occurrence of nanoleakage at the resin-dentin interface using the same specimens. METHODS Resin-dentin-bonded micro-specimens (sticks with a size of 300 microm x 300 microm x 8mm) were prepared using one of two material combinations (group I: Syntac classic/Tetric Ceram Cavifil: n=57; group II: Prime & Bond NT/Spectrum TPH: n=52). After immersion of the micro-specimens in 0.1% rhodamine-B solution for 1h, nanoleakage was imaged nondestructively using a confocal laser scanning microscope (CLSM). Then the specimens were subjected to a microTBS test. RESULTS For the influence of nanoleakage on microTBS with the Syntac classic/Tetric Ceram Cavifil group, the nonparametric Spearman correlation was 0.033 at p=0.805. For the Prime & Bond NT/Spectrum TPH group, the nonparametric Spearman correlation was 0.077 at p=0.584. SIGNIFICANCE The degree of nanoleakage had no influence on microtensile bond strength for the Syntac classic/Tetric Ceram Cavifil or for the Prime & Bond NT/Spectrum TPH group.

Loss of molars in periodontally treated patients: results 10 years and more after active periodontal therapy

AIM To identify risk factors for loss of molars during supportive periodontal therapy (SPT). MATERIALS AND METHODS A total of 136 subjects with 1015 molars at baseline were examined retrospectively. The association of risk factors with loss of molars was assessed using a multilevel Cox regression analysis. Furcation involvement (FI) was assessed clinically at start of periodontal therapy and assigned according to Hamp et al. (1975). RESULTS Fifty molars were extracted during active periodontal therapy (APT) and 154 molars over the average SPT period of 13.2 ± 2.8 years. FI degree III (HR 4.68, p < 0.001), baseline bone loss (BL) > 60% (HR 3.74, p = 0.009), residual mean probing pocket depth (PPD, HR 1.43, p = 0.027), and endodontic treatment (HR 2.98, p < 0.001) were identified as relevant tooth-related factors for loss of molars during SPT. However, mean survival time for molars with FI III or BL > 60% were 11.8 and 14.4 years, respectively. Among the patient data, age (HR 1.57, p = 0.01), female gender (HR 1.99, p = 0.035), smoking (HR 1.97, p = 0.034), and diabetes mellitus (HR 5.25, p = 0.021) were significant predictors for loss of molars. CONCLUSION Overall, periodontal therapy results in a good prognosis of molars. Degree III FI, progressive BL, endodontic treatment, residual PPD, age, female gender, smoking, and diabetes mellitus strongly influence the prognosis for molars after APT.

Enamel Matrix Derivative in Propylene Glycol Alginate for Treatment of Infrabony Defects With or Without Systemic Doxycycline: 12- and 24-Month Results

BACKGROUND This aim of this study is to compare regenerative therapy of infrabony defects with and without administration of post-surgical systemic doxycycline (DOXY) 12 and 24 months after therapy. METHODS In each of 57 patients, one infrabony defect (depth ≥ 4 mm) was treated regeneratively using enamel matrix derivative at two centers (Frankfurt am Main and Heidelberg). By random assignment, patients received either 200 mg DOXY per day or placebo (PLAC) for 7 days after surgery. Twelve and 24 months after surgery, clinical parameters (probing depths [PDs] and vertical clinical attachment level [CAL-V]) and standardized radiographs were obtained. Missing data were managed according to the last observation carried forward. RESULTS Data of 57 patients (DOXY: 28; PLAC: 29) were analyzed (26 males and 31 females; mean age: 52 ± 10.2 years; 13 smokers). In both groups, significant (P <0.01) PD reduction (DOXY: 3.7 ± 2.2 mm; PLAC: 3.4 ± 1.7 mm), CAL-V gain (DOXY: 2.7 ± 1.9 mm; PLAC: 3.0 ± 1.9 mm), and bone fill (DOXY: 1.6 ± 2.7 mm; PLAC: 1.8 ± 3.0 mm) were observed 24 months after surgery. However, the differences between both groups failed to be statistically significant (PD: P = 0.574; CAL-V: P = 0.696; bone fill: P = 0.318). CONCLUSIONS Systemic DOXY, 200 mg/day for 7 days, after regenerative therapy of infrabony defects did not result in better PD reduction, CAL-V gain, or radiographic bone fill compared with PLAC 12 and 24 months after surgery, which may be attributable to low power and, thus, random chance.

Reproducibility of a commercially available subgingival plaque sampling strategy and analysis strategy with oligonucleotide probes.

Abstract Objectives: The aim was to evaluate the intra-test agreement of pooled samples from the deepest periodontal pocket of each quadrant with a commercially available test kit based on hybridization of 16S rRNA. Material and methods: Plaque samples of 50 patients with generalized severe chronic periodontitis before therapy were pooled in two separate vials in order to detect and compare counts of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. Cohen’s κ and interclass correlation coefficients were calculated to judge intra-test agreement. Results: Cohen’s κ for detection and counts of Tannerella forsythia and Treponema denticola showed a perfect agreement. Porphyromonas ginigivalis was identified in both tests with a substantial agreement, whereas detection of Aggregatibacter actinomycetemcomitans varied in eight patients resulting in a good agreement. Possible confounding factors could not be identified statistically. Conclusion: Test results of the commercial 16S rRNA test are perfectly reproducible regarding detection of red complex pathogens. Intra-test agreement concerning detection of Aggregatibacter actinomycetemcomitans was less favorable. Clinical relevance: Detection of certain periodontal pathogens may alter the treatment and lead to prescription of antibiotics parallel to mechanical debridement. It is quite important not to use antibiotics excessively. Thus, the basis for decision-making in favor of antibiotics should be solid.