Raluca Cosgarea

MR-Imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT

ObjectivesThe aim of this study was (1) to assess the ability of magnetic resonance imaging (MRI) to visualize dental and periodontal structures and (2) to compare findings with multidetector computed tomography (MDCT) and cone beam CT (CBCT).Materials and methodsFour porcine mandibles were examined with (1) 3T-MRI, (2) MDCT and (3) CBCT. Two observers independently reviewed MR, MDCT and CBCT images and assessed image quality of different dental and periodontal structures. To assess quantitatively the accuracy of the different imaging technique, both observers measured burr holes, previously drilled in the mandibles.ResultsDental structures, e.g. teeth roots, pulpa chamber and dentin, were imaged accurately with all imaging sources. Periodontal space and cortical/trabecular bone were better visualized by MRI (p < 0.001). MRI could excellently display the lamina dura, not detectable with MDCT and only inconstant visible with CBCT (p < 0.001). Burr hole measurements were highly precise with all imaging techniques.ConclusionsThis experimental study shows the diagnostic feasibility of MRI in visualization of teeth and periodontal anatomy. Detection of periodontal structures was significantly better with MRI than with MDCT or CBCT. Prospective trials have to evaluate further the potential benefit of MRI in a clinical setting.

Cleavage of extracellular matrix in periodontitis: gingipains differentially affect cell adhesion activities of fibronectin and tenascin-C.

Gingipains are cysteine proteases that represent major virulence factors of the periodontopathogenic bacterium Porphyromonas gingivalis. Gingipains are reported to degrade extracellular matrix (ECM) of periodontal tissues, leading to tissue destruction and apoptosis. The exact mechanism is not known, however. Fibronectin and tenascin-C are pericellular ECM glycoproteins present in periodontal tissues. Whereas fibronectin mediates fibroblast adhesion, tenascin-C binds to fibronectin and inhibits its cell-spreading activity. Using purified proteins in vitro, we asked whether fibronectin and tenascin-C are cleaved by gingipains at clinically relevant concentrations, and how fragmentation by the bacterial proteases affects their biological activity in cell adhesion. Fibronectin was cleaved into distinct fragments by all three gingipains; however, only arginine-specific HRgpA and RgpB but not lysine-specific Kgp destroyed its cell-spreading activity. This result was confirmed with recombinant cell-binding domain of fibronectin. Of the two major tenascin-C splice variants, the large but not the small was a substrate for gingipains, indicating that cleavage occurred primarily in the alternatively spliced domain. Surprisingly, cleavage of large tenascin-C variant by all three gingipains generated fragments with increased anti-adhesive activity towards intact fibronectin. Fibronectin and tenascin-C fragments were detected in gingival crevicular fluid of a subset of periodontitis patients. We conclude that cleavage by gingipains directly affects the biological activity of both fibronectin and tenascin-C in a manner that might lead to increased cell detachment and loss during periodontal disease.

Prognostic value of the periodontal risk assessment in patients with aggressive periodontitis

OBJECTIVES Aim of the study was to evaluate the predictive value of the modified periodontal risk assessment (PRA) in patients with aggressive periodontitis (AgP) for the first time. MATERIAL AND METHODS A total of 86 Patients with AgP were re-examined 5-17 years after active periodontal treatment. Risk profile according to the modified PRA was assigned and regularity of maintenance monitored. Tooth loss, bone loss and recurrence of periodontitis were analysed in association with gender, diagnosis, compliance and risk profile using uni- and multivariate parametric regression and Cox proportional hazards models. RESULTS A total of 14 patients showed a localized AgP, 60 a high-risk-profile and 19 were compliant with the proposed maintenance-interval. Of 2202 teeth 98 were lost. Multivariate analysis could not assign a statistically significant impact to risk-profile. By excluding Interleukin-1 composite genotype from the modified PRA a significant influence (p = 0.003, HR 2.74) was detected. The impact of compliance was shown to be nearly significant (p = 0.059, HR 2.0). In patients with generalized AgP a tendency for increased tooth loss was found. CONCLUSION The prognostic value of the modified PRA could not be confirmed in patients with AgP. However, exclusion of Interleukin-1 composite genotype led to a model with significant influence on tooth loss.

Comparison of two different microbiological test kits for detection of periodontal pathogens

Abstract Objective. The aim of this study was to compare the outcome of two different microbiological tests for detection of Aggregatibacter actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), Tannerella forsythia (T.f.) and Treponema denticola (T.d.). Material and methods. A total of 69 adult patients with severe chronic (sCP) or aggressive periodontitis (AgP) participated in the study. Microbiological samples were examined for A.a., P.g., T.f. and T.d. using an RNA probe test (PADO) and a real-time polymerase chain reaction test (MERI). Results. For all periodontal pathogens under investigation, the median bacterial counts detected with PADO were smaller compared to those detected with MERI. P.g., T.f. and T.d. could be found in the majority of all patients with both tests. With MERI, A.a. was detected more often (24.6%) than with PADO (18.8%). Only 10.1% of the patients tested positive for A.a. with both tests. Conclusion. Both tests showed a high percentage of agreement for P.g., T.f. and T.d., but exhibited marked differences in the detection of A.a.

Periodontal pathogens and associated factors in aggressive periodontitis: results 5–17 years after active periodontal therapy

OBJECTIVES To assess the association between presence of periodontal pathogens and recurrence of disease in patients with aggressive periodontitis (AgP) after active periodontal therapy (APT) and further influencing factors. MATERIAL & METHODS Microbiological samples were taken from 73 patients with AgP 5-17 years after APT at 292 sites (deepest site per quadrant). Real-time polymerase chain reactions were used to detect the periodontal pathogens Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. Uni- and multivariate analyses evaluated the associations between pathogens and recurrence of disease, smoking and adjunctive antibiotic therapy. RESULTS At re-examination A. actinomycetemcomitans could be detected in six patients (8.2%), P. gingivalis in 24 (32.9%), T. forsythia in 31 (42.5%) and T. denticola in 35 (48.0%). Increased levels of T. forsythia and T. denticola at re-examination were significantly associated with recurrence of disease in multivariate analyses (OR: 12.72, p < 0.001; OR 5.55, p = 0.002 respectively). Furthermore, high counts of T. denticola were found in patients with increased percentage of sites with clinical attachment levels (CAL) ≥ 6 mm compared to those with low counts (13.8% versus 3.2%, p = 0.005). CONCLUSION In patients with recurrence of disease T. forsythia and T. denticola were detected more frequently and in higher counts. Furthermore, T. denticola was found more frequently in patients with increased CAL.

IL-1-polymorphism and severity of periodontal disease

Abstract Objective. To determine the association between the interleukin (IL)-1-polymorphism and the severity of periodontal disease prior to active periodontal therapy. Materials and methods. Two hundred and six patients with obtained baseline x-rays were tested for IL-1-polymorphism. Relative bone loss before active periodontal treatment was measured with a Schei ruler and classified in five groups. Descriptive statistics and backward stepwise linear regression analyses were performed. Results. Forty-nine patients with moderate (mChP), 79 with severe chronic (sChP) and 78 with aggressive periodontitis (AgP) were included. Age correlated significantly with bone loss and number of teeth at baseline. Gender, smoking and IL-1-polymorphism were neither associated with bone loss nor with number of teeth prior to treatment. After adjusting for age as well as gender, AgP was significantly associated with more severe bone loss in untreated periodontal disease (p = 0.036). In non-smokers, mean number of teeth prior to active periodontal therapy correlated significantly with presence of IL-1 polymorphism. Conclusion. The IL-1-polymorphism is associated with lower number of teeth in non-smokers with untreated periodontal disease. Untreated AgP is associated with more severe bone loss than untreated ChP.

Clinical evaluation of a porcine acellular dermal matrix for the treatment of multiple adjacent class I, II, and III gingival recessions using the modified coronally advanced tunnel technique.

OBJECTIVE To evaluate the clinical efficacy of a new porcine acellular dermal matrix (PADM) for the treatment of Miller Class I, II, and III multiple gingival recessions using the modified coronally advanced tunnel technique (MCAT). METHOD AND MATERIALS Twelve nonsmoking, systemically healthy patients presenting at least two adjacent Miller Class I, II, or III gingival recessions (GR), with a minimal depth of 2 mm, were treated consecutively with MCAT in conjunction with PADM. At baseline and 12 months postoperatively, complete root coverage (CRC, eg 100% root coverage), mean root coverage (RC), recession depth, recession width, attached gingiva (AG), keratinized tissue (KT), periodontal pocket depths (PD), and clinical attachment level (CAL) were evaluated. The main outcome variable was CRC. RESULTS Postoperative healing was uneventful in all cases, without any matrix loss or exposure or infection. Statistically significant improvements (P < .0001) were observed 12 months postoperatively in 53 of the included 54 GR (98.15%). Twenty two recessions (40.74%) showed CRC while the mean RC measured 73.20 ± 27.71%. Mean GR reduction was 2.06 ± 1.18 mm while the gain of AG amounted to 0.84 ± 0.73 mm and of KT to 0.69 ± 0.51 mm, respectively. There were no statistically significant changes for PD at 12 months; CAL showed a significant decrease (P < .05) at 12 months from 3.77 ± 1.28 mm to 2.30 ± 1.02 mm. CONCLUSION PADM in conjunction with MCAT may be successfully utilized for the treatment of Miller Class I, II, and III multiple adjacent GR.

One year results of a randomized controlled clinical study evaluating the effects of non-surgical periodontal therapy of chronic periodontitis in conjunction with three or seven days systemic administration of amoxicillin/metronidazole

Background To evaluate the clinical outcomes 12 months after systemic administration of amoxicillin (AMX) and metronidazole (MET) adjunctive to subgingival debridement (SD) in patients with severe chronic periodontitis (sChP). Material and methods 102 patients with sChP were treated randomly as follows: SD within 2 consecutive days and placebo for 7 days (group A), SD+AMX+MET (both 500mg x3 times daily TID) for 3 days (group B), SD+AMX+MET (both 500mg x 3 TID) for 7 days (group C). At baseline, at 3-, 6-, and 12-months post-treatment probing pocket depth (PD), clinical attachment level (CAL), furcation involvement, bleeding on probing (BOP), full-mouth plaque score (FMPS) were determined. The reduction in the number of sites with PD≥6mm was defined as main outcome variable. Results 75 patients completed the study. At 12 months, all three treatment groups showed statistically significant improvements (p<0.001) of mean PD, CAL, BOP and number of sites with PD≥6mm compared to baseline. Mean residual PD were statistically significantly lower and CAL gain statistically significantly greater in the two antibiotic groups as compared to placebo. While PD reductions (p = 0.012) and CAL gain (p = 0.017) were statistically significantly higher in group C compared to group A, only the 3-day AB group showed statistically significantly fewer sites with PD≥6mm at 12 m (p = 0.003). The reduction in the number of sites with PD≥6 mm (primary outcome) showed no statistical significant differences between the 3 treatment groups. However, in both antibiotic groups significantly more patients compared to the placebo group reached a low risk for disease progression at 12 months (≤4 sites with PD≥5mm). Conclusion At 12 months, both adjunctive antibiotic protocols resulted in statistically significantly greater clinical improvements compared to placebo.