Christof E. Dörfer

Periodontal Disease as a Risk Factor for Ischemic Stroke

Background and Purpose— Chronic infectious diseases may increase the risk of stroke. We investigated whether periodontal disease, including periodontitis and gingivitis, is a risk factor for cerebral ischemia. Methods— We performed a case-control study with 303 patients examined within 7 days after acute ischemic stroke or transient ischemic attack, 300 population controls, and 168 hospital controls with nonvascular and noninflammatory neurological diseases. All subjects received a complete clinical and radiographic dental examination. The individual mean clinical attachment loss measured at 4 sites per tooth served as the main indicator for periodontitis. Results— Patients had higher clinical attachment loss than population (P <0.001) and hospital (P =0.010) controls. After adjustment for age, sex, number of teeth, vascular risk factors and diseases, childhood and adult socioeconomic conditions, and lifestyle factors, the risk of cerebral ischemia increased with more severe periodontitis. Subjects with severe periodontitis (mean clinical attachment loss >6 mm) had a 4.3-times-higher (95% confidence interval, 1.85 to 10.2) risk of cerebral ischemia than subjects with mild or without periodontitis (≤3 mm). Severe periodontitis was a risk factor in men but not women and in younger (<60 years) but not older subjects. Periodontitis increased the risk of cerebral ischemia caused by large-artery atherosclerosis, cardioembolism, and cryptogenic etiology. Gingivitis and severe radiologic bone loss were also independently associated with the risk of cerebral ischemia, whereas caries was not. Conclusions— Our study indicates that periodontal disease, a treatable condition, is an independent risk factor for cerebral ischemia in men and younger subjects.

Lack of association between polymorphisms of the toll-like receptor 4 gene and cerebral ischemia

Abstract.Toll-like receptor-4 (TLR4), an important mediator of the innate immune response, is expressed in atherosclerotic lesions. The common single nucleotide exchange (Asp299Gly) of the TLR4 gene has been previously reported to impair TLR4 function and to be associated with a decreased risk of carotid atherosclerosis. Therefore, we aimed to detect the potential impact of TLR4 genotypes on the risk of cerebral ischemia.We studied the prevalence of two common polymorphisms of the TLR4 gene (Asp299Gly and Thr399Ile) in 3 independent study populations: (1.) in a cross-sectional study including 769 patients either with type 1 or type 2 diabetes mellitus, of whom 56 (7.2%) had a history of cerebral ischemia (study 1), (2.) a case-control study (study 2) including 128 consecutive patients with cerebral ischemia, mean age 60 ± 10.9 years and 139 control subjects, and (3.) a case-control study (study 3) including 171 young adults aged < 50 years with cerebral ischemia and 204 control individuals. In all subjects, Asp299Gly and Thr399Ile were detected by restriction length analysis.The prevalence of the TLR4 genotypes was essentially the same between patients with cerebral ischemia and control subjects in all 3 study populations. Furthermore, there was also no association with the subgroup of atherosclerotic stroke in both case-control studies populations.Although TLR4 polymorphisms are associated with a decreased risk of carotid atherosclerotic lesions, our findings indicate that they do not influence the prevalence of cerebral ischemia. This implies that the Asp299GlyTLR4-allele might have a protective role in carotid atherosclerosis, but not in cerebral ischemia.

Lipopolysaccharide receptor CD14 polymorphism and risk of stroke in a South-German population

Abstract.Background: The monocyte receptor for bacterial lipopolysaccharide CD14 is an important mediator of the inflammatory response. Recently, a polymorphism in the promotor of the CD14 gene, C (−260) T, was detected as a risk factor for coronary heart disease. Objective: We tested the hypotheses that this polymorphism is a risk factor 1. for cerebral ischemia in general and 2. for cerebral ischemia due to large artery atherosclerosis or microangiopathy in particular. Patients and Methods: We performed a case control study including 151 consecutive patients with acute cerebral ischemia treated at our university hospital and 149 control subjects. All control subjects were randomly selected from the general population of the same region in South-West Germany. Genotype frequencies of the C(−260) T polymorphism in the promotor of the CD14 gene were examined by restriction length analysis. Results: The TT-genotype was not associated with cerebral ischemia in general either in univariate or in multivariate analysis together with classical vascular risk factors (odds ratio in multivariate analysis: 1.11; 95 %CI, 0.63 to 1.95). In 70 patients with cerebral ischemia due to atherosclerosis of large arteries or microangiopathy, there was a significantly higher prevalence of the TT-genotype than into control subjects (38.6 % vs. 23.5 %; odds ratio in multivariate analysis 2.26; 95 %CI, 1.13 to 4.54). Conclusions: We demonstrated that the TT-genotype of the CD14 C(−260) T polymorphism in a South-German population is not associated with an increased risk of cerebral ischemia in general. However, we found that the TT-genotype is associated with a risk of atherosclerotic or microangiopathic stroke. This finding requires confirmation by future studies in larger populations.

Guided tissue regeneration with bioabsorbable barriers III 10-year results in infrabony defects

OBJECTIVEnEvaluation of the 10-year results after GTR-therapy of infrabony defects using two bioabsorbable barriers in a randomized-controlled clinical trial.nnnMATERIAL AND METHODSnIn 15 patients with periodontitis, 15 pairs of infrabony defects were treated. For each patient, one defect received a polydioxanon (test: T) and the other received a polylactide acetyltributyl citrate (control: C) barrier by random assignment. At baseline, 12 and 120 +/- 6 months after surgery, the clinical parameters and standardized radiographs were obtained.nnnRESULTSnNine patients were available for the 120-month re-examinations. Twelve and 120 +/- 6 months after therapy statistically significant (p<or=0.004) vertical probing attachment level (PAL-V) gain was found in both groups (T12: 3.9 +/- 1.6 mm; T120: 2.4 +/- 1.8 mm; C12: 4.0 +/- 1.1 mm; C120: 2.4 +/- 1.7 mm). From 12 to 120 months both groups experienced PAL-V loss (T: 1.4 +/- 1.5 mm, p=0.021; C: 1.6 +/- 2.5 mm, p=0.09). After 120 month, two teeth were lost in the control group (one periapical lesion, and one due to unknown reason). The study failed to show statistically significant differences between both groups regarding PAL-V gain 120 months after surgery.nnnCONCLUSIONSnPAL-V gain achieved after GTR therapy in infrabony defects using both bioabsorbable barriers was stable after 10 years in 15 of 22 defects (68%).

Gingival Mesenchymal Stem/Progenitor Cells: A Unique Tissue Engineering Gem

The human gingiva, characterized by its outstanding scarless wound healing properties, is a unique tissue and a pivotal component of the periodontal apparatus, investing and surrounding the teeth in their sockets in the alveolar bone. In the last years gingival mesenchymal stem/progenitor cells (G-MSCs), with promising regenerative and immunomodulatory properties, have been isolated and characterized from the gingival lamina propria. These cells, in contrast to other mesenchymal stem/progenitor cell sources, are abundant, readily accessible, and easily obtainable via minimally invasive cell isolation techniques. The present review summarizes the current scientific evidence on G-MSCs isolation, their characterization, the investigated subpopulations, the generated induced pluripotent stem cells- (iPSC-) like G-MSCs, their regenerative properties, and current approaches for G-MSCs delivery. The review further demonstrates their immunomodulatory properties, the transplantation preconditioning attempts via multiple biomolecules to enhance their attributes, and the experimental therapeutic applications conducted to treat multiple diseases in experimental animal models in vivo. G-MSCs show remarkable tissue reparative/regenerative potential, noteworthy immunomodulatory properties, and primary experimental therapeutic applications of G-MSCs are very promising, pointing at future biologically based therapeutic techniques, being potentially superior to conventional clinical treatment modalities.

Guided tissue regeneration with bioabsorbable barriers. II. Long-term results in infrabony defects.

BACKGROUNDnThe aim of this 5-year randomized controlled clinical trial was to evaluate the long-term results after guided tissue regeneration (GTR) therapy of infrabony defects using two bioabsorbable barriers.nnnMETHODSnFifteen pairs of contralateral infrabony defects in 15 patients with moderate to severe periodontitis were treated. Each patient received one polydioxanon (test: T) and one polylactide acetyltributyl citrate (control: C) barrier by random assignment. At baseline, 12, and 60 +/- 3 months after surgery clinical parameters and standardized radiographs were obtained. Vertical bone levels (PBL-V) were measured during surgery and 60 +/- 3 months later by transgingival bone sounding.nnnRESULTSnThirteen patients were available for the 60-month examinations. Twelve and 60 +/- 3 months after GTR, statistically significant (P< or =0.001) vertical attachment (CAL-V) gain was found in both groups (T12: 3.5 +/- 1.5 mm; T60: 2.2 +/- 1.8 mm; C12: 4.0 +/- 0.9 mm; C60: 2.4 +/- 1.0 mm). However, from 12 to 60 months after therapy both groups experienced significant CAL-V loss (P<0.05): two defects in the test group and three in the control group had CAL-V loss >2 mm compared to the 12-month reexamination. Twelve and 60 +/- 3 months after surgery, statistically significant (P<0.05) radiographic bony fill was found in both groups (T12: 1.2 +/- 1.3 mm; T60: 1.5 +/- 2.2 mm; C12: 0.9 +/- 1.4 mm; C60: 1.0 +/- 1.6 mm). Further, 60 months after surgery significant (P<0.05) PBL-V gain was found in both groups (test: 1.8 +/- 2.3 mm; control: 2.2 +/- 1.8 mm). The study failed to show statistically significant differences between test and control regarding CAL-V and PBL-V gain 60 months after surgery.nnnCONCLUSIONnCAL-V gain achieved after GTR therapy in infrabony defects using both bioabsorbable barriers was stable after 5 years in 21 of 26 defects (81%).

Effect of cavity preparation instruments (oscillating or rotating) on the composite–dentin interface in primary teeth

OBJECTIVESnTo evaluate the effect of preparation of instruments on the interfacial integrity between cavity wall and composite restoration.nnnMETHODSnTwo class II slot preparations were done in 10 primary teeth either with SonicSys or with a conventional bur. The cavities were filled using an adhesive system. One layer of a flowable composite and one layer of a condensable composite were applied. The specimens were analyzed by confocal laser scanning microscopy.nnnRESULTSnIn the SonicSys group the mean thickness of the hybrid layer was 6.12 (0.60) microm; in the control group it was 6.04 (0.63) microm. The difference was not statistically significant. Two fractures were observed in one tooth of each group. These were located only in the enamel. The cavity margins were beveled in all specimens.nnnSIGNIFICANCEnCompared to conventional preparations, cavity preparation with SonicSys has no deleterious effect on the integrity of the interface.

Periodontal Probing Versus Radiographs for the Diagnosis of Furcation Involvement

BACKGROUNDnDecisions in periodontal therapy for multirooted teeth are essentially based on accurate diagnosis of the furcation involvement (FI). Furcation probing (FP) is still the basic diagnostic measure, although the assessment may be difficult. The aim of this study is to evaluate the validity of FP and radiographic assessment of FI compared with visual assessment during open flap surgery (OFS).nnnMETHODSnIn this retrospective clinical cohort study, 215 participants with periodontal disease and at least one molar treated with OFS were enrolled, and a total of 834 molars were assigned for FI by FP and in radiographs analyzed by an experienced (EE) and less experienced examiner (LE). For the investigation, 143 panoramic radiographs (OPGs) and 77 intra-oral radiographs (I-Os) were evaluated.nnnRESULTSnThe Class of FI by FP was confirmed in 56%, whereas 15% were overestimated and 29% underestimated. FI Class 0 and I had been detected with high probability (74% and 54%, respectively). Of all FI Class III, 57% were detected correctly by radiographs and 32% by FP. FP and OFS revealed a weighted κ-coefficient (κw) = 0.588; radiographs and OFS had κw = 0.542 (OPG κw = 0.555 and I-O κw = 0.521). The interrater reliability for radiographs was dependent on the experience of the examiner (EE κw = 0.618; LE κw = 0.426).nnnCONCLUSIONSnExperience in analyzing conventional radiographs increases the potential of correct diagnosis of advanced FI. The reliability of FP compared with radiographic assessment depends on the anatomy and location of the tooth. Both diagnostic tools should be used in cases of suspected FI.

TlR expression profile of human gingival margin-derived stem progenitor cells

Background Gingival margin-derived stem/progenitor cells (G-MSCs) show remarkable periodontal regenerative potential in vivo. During regeneration, G-MSCs may interact with their inflammatory environment via toll-like-receptors (TLRs). The present study aimed to depict the G-MSCs TLRs expression profile. Material and Methods Cells were isolated from free gingival margins, STRO-1-immunomagnetically sorted and seeded to obtain single colony forming units (CFUs). G-MSCs were characterized for CD14, CD34, CD45, CD73, CD90, CD105, CD146 and STRO-1 expression, and for multilineage differentiation potential. Following G-MSCs’ incubation in basic or inflammatory medium (IL-1β, IFN-γ, IFN-α, TNF-α) a TLR expression profile was generated. Results G-MSCs showed all stem/progenitor cells’ characteristics. In basic medium G-MSCs expressed TLRs 1, 2, 3, 4, 5, 6, 7, and 10. The inflammatory medium significantly up-regulated TLRs 1, 2, 4, 5, 7 and 10 and diminished TLR 6 (p≤0.05, Wilcoxon-Signed-Ranks-Test). Conclusions The current study describes for the first time the distinctive TLRs expression profile of G-MSCs under uninflamed and inflamed conditions. Key words:Stem cells, TLR, gingiva, polymerase chain reaction, FACS.

In vitro cleaning efficacy and resistance to insertion test of interdental brushes

The aim of this study was to compare the resistance to insertion forces and cleaning efficacy values of triangular interdental brushes (TIB) and conventional round interdental brushes (RIB). Extracted human teeth were fixed in a socket and matched to pairs simulating interdental spaces. Before and after standardized cleaning of the proximal surfaces, the pre- and postbrushing situations were registered with a digital camera. The cleaning efficacy was quantified by digital image subtraction. The forces necessary for insertion were measured with a load cell. The ratio between the relative cleaning efficacy and the forces necessary for insertion was calculated. The results of our study revealed that the relative cleaning efficacies of round and TIB were equal. There were no statistically significant differences. TIB showed significantly lower resistance to insertion values. Consequently, at identical resistance to insertion the TIB cleaned more effectively compared with the RIB, which means that the same effectiveness was reached by significantly lower forces at insertion. TIB showed a more favorable ratio between relative cleaning efficacy and resistance to insertion than RIB.