Synchrotron-based X-ray tomographic microscopy for visualization of three-dimensional collagen matrices.

INTRODUCTION: Three-dimensional collagen matrices (3D-CMs) may be visualized by cumbersome reconstructions of serial sections. We report here on the method of synchrotron-based X-ray tomographic microscopy (SRXTM) to image 3D-CMs in native tissue probes. MATERIAL AND METHODS: SRXTM of 3D-CMs (mucoderm®, mucograft®) was performed at the TOMCAT beamline of the Swiss Light Source (SLS) at the Paul Scherrer Institute (Villigen, Switzerland). RESULTS: SRXTM combines the advantages of high-resolution scanning electron microscopy (SEM) imaging with the low-resolution reconstructions of micro-CT (µCT) imaging. It may be used to non-destructively visualize and analyze structures within the 3D-CMs without the need of serial sectioning and reconstruction. CONCLUSION: High-resolution SRXTM is a useful tool in analyzing the topology and morphometry of structures in 3D-CMs. The outcome justifies the efforts in sophisticated data processing. CLINICAL RELEVANCE: SRXTM may help to understand the clinical characteristics of 3D-CMs in more detail.

The impact of some behavioral aspects on periodontal disease in a group of Romanian students - an epidemiological survey.

AIMS: To investigate the prevalence of periodontitis in a young population representative for the North-western part of Romania (Transylvania) and to identify possible risk indicators of periodontitis. METHODS: The study is a cross-sectional epidemiological survey. The subjects were students randomly sampled from three universities in Cluj-Napoca and high school students from the neighboring city of Bistrita. The sample size of the population was calculated. Overall, 623 subjects aged 16-35 years were evaluated, of which 488 were university students and 135 high school students. A structured questionnaire was administrated to collect information on socio-behavioral status and oral hygiene habits. Periodontal data was collected using a full-mouth methodology by trained examiners. A recent introduced case definition was used to pick up periodontitis cases. RESULTS: The older the subject, the more frequent toothbrushing, dental visits, and use of interproximal hygiene devices, but also addiction to tobacco and alcohol consumption. The prevalence of periodontitis was 0.96% (n=6). Half of these subjects (n=3, 0.48%) were considered to have aggressive periodontitis (AP). Low frequency of toothbrush changing was identified to influence the development of periodontitis. Smoking and lower socioeconomic level did not seem to correlate with periodontal disease in the present study. CONCLUSIONS: In order to better understand the prevalence of periodontal diseases and identify periodontitis cases as well as to evaluate the impact of specific behavioral factors on the disease development in individual and population levels, further extensive screenings are obviously required. Periodontal prevention programs focusing on oral health behavior are mandatory.

In vitro and in vivo characterization of porcine acellular dermal matrix for gingival augmentation procedures.

BACKGROUND AND OBJECTIVE: Recently, porcine acellular dermal matrix (PADM) has been proposed as a possible alternative to autogenous grafts in periodontal plastic surgery. The aim of the present study was to investigate the in vitro responses of four different oral cell lines cultured on a novel PADM. Furthermore, tissue reaction to PADM was evaluated histologically after subcutaneous implantation in mice. MATERIAL AND METHODS: Human gingival fibroblasts (HGF), human osteoblast-like cells, human umbilical vein endothelial cells and human oral keratinocytes (HOK) were cultured and transferred on to the PADM. A tissue culture polystyrene surface served as the control. The viability of all tested cell lines on PADM was measured by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay and PrestoBlue(®) reagent. The ToxiLight(®) assay was performed to analyze the effect of PADM on adenylate kinase release. PADM was implanted into nude mice subcutaneously and subjected to histological analysis after 21 d. RESULTS: Using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assays, all tested cell lines cultured on PADM demonstrated a significant increase of viability compared to the control group (each p < 0.001) with the exception of HGF and HOK after 3 d (each p > 0.05). According to the PrestoBlue(®) analysis, all cell lines demonstrated a significant increase of viability compared to the control group at the particular points of measurement after 18 h (HGF p < 0.01; human osteoblast-like cells, human umbilical vein endothelial cells, HOK each p < 0.001). No significant cytotoxic effects of PADM on the tested cell lines could be observed, as assessed by changes in adenylate kinase release. Subcutaneous implantation of PADM into nude mice demonstrated good integration with surrounding tissues and significant revascularization of its collagen structure. CONCLUSION: Overall, the results suggest that PADM is a promising substitute for autogenous soft tissue grafts in periodontal surgery.

Subepithelial connective tissue graft with or without enamel matrix derivative for the treatment of Miller class I and II gingival recessions: a controlled randomized clinical trial.

BACKGROUND: The aim of this study was to evaluate whether the combination of enamel matrix derivative (EMD) with subepithelial connective tissue graft (SCTG) plus coronally advanced flap (CAF) would improve the treatment outcomes of Miller class I and II gingival recessions when compared with the same technique (SCTG plus CAF) alone. METHODS: The study was designed as a randomized, parallel, controlled, double-blinded clinical trial. Forty-two patients were randomly assigned in the test group (SCTG plus EMD) and in the control group (SCTG). Patients had at least one gingival recession ≥ 2 mm. The clinical parameters were evaluated at baseline and at 14 d, 1, 3, 6 and 12 mo follow-up time points. RESULTS: Forty-two patients, 21 in the test group (SCTG plus EMD) and 21 in the control group (SCTG), aged 21-48 years (mean age 31 ± 8.56) were initially included in the study. Both treatments, STCG plus EMD and SCTG, resulted in a significant final mean root coverage (2.91 ± 0.95mm and 2.91 ± 1.29 mm, respectively) (p < 0.001) and in a high mean percentage of root coverage (82.25 ± 22.20% and 89.75 ± 17.33%, respectively) (p < 0.001), 1 year after surgery. The differences in mean root coverage recorded for the two techniques after 1 year, were not statistically significant (p = 0.19). Complete root coverage was achieved in 56.5% of patients treated with SCTG plus EMD and in 70.6% of patients treated with SCTG (p = 0.275), 1 year after treatment. CONCLUSIONS: The present study failed to demonstrate any additional clinical benefits when EMD was added to SCTG plus CAF.

The influence of enamel matrix derivative on the angiogenic activity of primary endothelial cells.

BACKGROUND AND OBJECTIVE: Angiogenesis plays a crucial role in early wound healing and tissue regeneration. Although enamel matrix derivative (EMD) has demonstrated the potential to stimulate periodontal regeneration, the biological effects of EMD on angiogenesis and underlying mechanisms have not been fully elucidated. The aim of the present study was to examine the angiogenic effects of EMD in vitro. MATERIAL AND METHODS: Human umbilical vein endothelial cells (HUVECs) were used to assess the effect of EMD on proliferation, survival, adhesion and migration. The effect of EMD on HUVEC angiogenesis was assessed by a three-dimensional sprouting assay. In order to understand the signalling mechanism of altered cell proliferation of HUVECs caused by EMD, the phosphorylation status of ERK1/2 and of the serine/threonine protein kinase Akt was analysed by western blot using phospho-specific antibodies. RESULTS: The proliferation of HUVECs was stimulated by 50 µg/mL EMD, whereas higher concentrations (≥100 µg/mL) resulted in an increased apoptotic rate. The mitogenic response to EMD was associated with the activation of ERK1/2. Enamel matrix derivative did not affect cell adhesion, but all concentrations of EMD tested (0.1-250 µg/mL) promoted migration of HUVECs. Furthermore, EMD induced capillary-like sprout formation from HUVEC spheroids in a dose-dependent manner. CONCLUSION: Our data indicate that EMD acts as a proangiogenic factor in vitro and, as such, might contribute to periodontal tissue regeneration by stimulation of vessel formation during wound healing.

Influence of gender and social factors on oral health, treatment degree and choice of dental restorative materials in patients from a dental school.

OBJECTIVE: The attitude towards oral health is influenced by gender, the level of education and the social background of the patients The aim of the present study was to determine a possible relationship of gender, the educational level and the oral health as well as the choice of dental restorations. METHODOLOGY: A total of 2374 outpatients (age: 18-80 years) from a University dental school were assessed. Inclusion criteria were 15 remaining teeth and good general health. In addition to anamnesis data, information concerning educational level and present occupation was collected. The dental assessment included number of teeth, endodontic treatment, type of restorations (root canal fillings, restoration materials) as well as dental panoramic radiographs (OPG). RESULTS: The female patients demonstrated a statistically significant higher percentage of restoration, more teeth with crowns and more tooth coloured fillings compared to men (P < 0.01). Patients with a higher level of education preferred more expensive restorations, whereas patients with a low level of education exhibited more inexpensive restorations. However, patients with private health insurance showed lower levels of carious lesions. CONCLUSION: The examined patients showed no significant correlation between educational level and type of dental restorations but female patients had a lower number of teeth and more restoration.

[Oral hygiene, prophylaxis and therapy in patients with inflammatory rheumatic diseases]. / Mundhygiene, Prophylaxe und Therapie bei entzündlich-rheumatischen Erkrankungen.

Inflammatory disorders of the periodontium are often associated with chronic systemic diseases, which can demonstrate a reciprocal influence. Within the adult population at present, 74% of younger adults and 88% of older individuals require periodontal treatment. Due to inflammatory processes, patients with rheumatoid arthritis or other chronic polyarthritides frequently suffer from pain in the temporomandibular joint and, since finger mobility is often limited, their ability to perform oral hygiene measures is impeded. However, diligent and constant oral hygiene is of crucial importance both for maintaining a healthy periodontium and to prevent the development of caries. For their daily dental care, these patients should favor the use of electric toothbrushes, products for interdental cleaning and mouth rinses. The dentist should be informed immediately about increased and constant gingival bleeding, gingival hyperplasia, loosening or migration of teeth associated with gingival recession or other irritations in the oral cavity. Professional dental cleaning should be routinely performed at 3- to 6-month intervals in order to prevent an increase in the risk for periodontal disease.

The determination of the initial straight length in root canals of mandibular premolars--an in vitro study.

The aim of the present roentgenographic in vitro study was to determine the initial straight length from the cemento-enamel junction (CEJ) to the appearance of a root canal curvature in human mandibular premolars. A total number of 282 mandibular premolars were examined. Exclusion criteria comprised root caries, extensive restorations and endodontically treated teeth. The teeth were fixed and digitally radiographed by means of a specially developed fixation device with standardized and reproducible distances with the parallel technique (Heliodent MD; Merlin 2.1). The distances from the CEJ to the first curvature (> 5 degrees ) (distance I), from the first curvature to a second curvature (distance II), and from the first or second curvature to the radiological apex (distance III) were recorded. The lengths of the initial straight distance and the appearance of a curvature were statistically analyzed and related to each other. In first mandibular premolars, the mean value for distance I was 10.9 mm, for distance II 3.7 mm and for distance III 3.04 mm. The mean values for the second mandibular premolars were 1.1mm in distance I, 4.3mm in distance II and 3.1mm in distance III. No statistically significant differences between left and right mandibular premolars could be observed regarding the canal curvature location and the angle values. The results of this investigation show that curvatures are increasingly observed 9 to 12 mm from the original path in mandibular premolars.

Periodontal conditions and oral hygiene in rural population of post-war Vukovar region, Croatia in correlation to stress.

OBJECTIVE: The greatest burden of oral diseases is on the socially marginalized population, such as those living in small villages and war areas. The aim of this study was to assess the periodontal conditions of people in post-war area villages in relation to oral hygiene, habits and war stress. METHODS: The study was conducted on a sample of 282 subjects (mean age 41.5 +/- 17.8) in seven Vukovar villages using the questionnaire and clinical periodontal examination. RESULTS: Five years after the war in Croatia the population was still very poor, low educated, and had a low level of periodontal health and oral hygiene habits. The level of periodontal disease and attachment loss tended to increase with age and physical activity and decrease with education level, higher frequency of tooth brushing and toothbrush replacement, dental visits and utilisation of auxiliary devices. Subjects exposed to any kind of war stress had a significantly worse periodontal status and more excluded sextants than those who were not exposed to such stress experience (p<0.05). Better periodontal conditions were found in individuals that were refugees, than those who were in war, wounded or lost a dear person (p<0.05). Individuals who were in war rarely brushed their teeth, visited dentist and changed toothbrushes, but more frequently drank alcohol and smoked, in comparison to other groups, especially those who have not been exposed to war stress. CONCLUSIONS: Specific socio-economic and psychological conditions in post-war areas could be significant risk factors for poor periodontal conditions.

The effectiveness of a novel optical probe in subgingival calculus detection.

OBJECTIVES: The aim of the present study was to evaluate the effectiveness of a novel optical calculus detection system under in vivo conditions. METHODS: One hundred and seventy-six tooth surfaces from 44 adult teeth that were indicated for extraction were selected for the present study. The patients were randomly assigned to one of the two experimental groups. In group A (n = 96), clinical presence or absence of subgingival calculus deposits was determined using the light-emitting diode-based optical probe (OP). In group B (n = 80), the subgingival deposits were first recorded with the OP followed by root surface debridement until no subgingival deposits could be detected by the device. Teeth were then extracted and examined under a stereomicroscope by two trained dentists (DENT 1, DENT 2) and a dental student. Results were compared with the measurements of the OP and direct visual control. RESULTS: In group A, post-extraction results revealed 89% and 90% agreement with the positive and negative OPs detection. In group B, 17% of the surfaces demonstrated even after subgingival debridement and control with the detecting device still calcified deposits in the microscopic evaluation. The highest inter-examiner agreements were observed between DENT 1 and DENT 2. CONCLUSION: It was shown that the optical detection system identifies subgingival calculus with a high efficacy and therefore, may be a support for the operator to determine the endpoint of root surface instrumentation.

Assessment of alveolar bone loss and angular bony defects on panoramic radiographs.

The aim of the present study was to investigate the prevalence and severity of alveolar bone loss and angular bony defects in randomly selected panoramic radiographs. A total of 500 panoramic radiographs of adult patients seeking dental care were studied. The mean age of the subjects was 51 years (range 20-80). The assessments of alveolar bone levels and angular bony defects were performed by direct measurements of the distance between the cemento-enamel junction (CEJ) and bone level. The results demonstrated a gradual and significant increase in the frequency of bone loss with increasing age (p<0.05). Angular bony defects were found in 249 subjects (49.8 %) and were most frequent at the mandibular first molar. The mean depth of the angular bony defects was 6.0 mm with the greatest mean depth in the maxillary anterior area (6.8 mm). The mean mesiodistal depth of the intrabony defects was 2.44 mm, most pronounced in maxillary molars (3.1 mm). In conclusion, the study demonstrated a high prevalence of angular bony defects suitable for regenerative periodontal treatment.

Digital volume tomography for diagnostics in periodontology.

The impact of radiographic imaging on the diagnosis and treatment of periodontal disease has essentially remained unchanged for decades. Thus, periodontal diagnosis relies primarly on traditional two-dimensional representation of the alveolar bone. Recently, digital volume tomography (DVT) has been introduced for head and neck applications. Major advantages of the DVT are a markedly reduced radiation exposure and superior image quality when compared to conventional computed tomography (CT). With this device, three-dimensional sectional images in the axial, frontal and sagittal plane can be obtained at one examination with tomographic slices of widths ranging from 0.125 to 2 mm. Clinical applications of this unit have been reported for implant site imaging, orthodontics, and temporomandibular joint imaging. Investigations regarding the usefulness of DVT for periodontal applications are still in progress. Thus, a field of interest for the use in periodontology might be the imaging of periodontal intrabony defects, dehiscence and fenestration defects, periodontal cysts as well as the diagnosis of furcation-involved molars.

Effect of an oily calcium hydroxide suspension (Osteoinductal) on human periodontal fibroblasts. An in vitro study.

The efficacy of an oily calcium hydroxide suspension (Osteoinductal) as an adjunct to periodontal regenerative therapy has been demonstrated in recent clinical and histological studies. However, little is known about the molecular mechanisms in vitro, particularly, about the effect of oily calcium hydroxide paste on periodontal ligament (PDL) cells. Therefore the aim of the present study was to analyze the mitogenic response of cultured PDL cells to Osteoinductal in comparison to calcium hydroxide and enamel matrix derivative (EMD) in vitro. Human periodontal ligament cells were derived from a third molar extracted for orthodontic reasons and incubated in the presence of Osteoinductal, calcium hydroxide, EMD, phosphate-buffered saline plus 10% glycerol (PBS) or standard culture medium for 15 and 60 minutes. The mitogenic response of the PDL cells was determined by Western Blot with antibodies specific for extracellular signal-related kinase (ERK)1/2 as well as the activated, tyrosine-phosphorylated form of ERK1/2 (p-ERK). Relative phosphorylation of ERK1/2 was normalized to total ERK1/2 levels by densitometry. Cell proliferation was measured after 1, 3 and 8 days using a Neubauer haemocytometer to determine the total cell number. Results demonstrated that the mitogenic response to Osteoinductal, calcium hydroxide and enamel matrix derivative was associated with the activation of ERK1/2 and was more pronounced as compared to PBS and standard culture medium treated cells. Although Osteoinductal and calcium hydroxide activated mitosis and caused phosphorylation of ERK1/2 in PDL cells, its effects were less pronounced as compared to EMD. Furthermore EMD exhibited the highest proliferative response in comparison to Osteoinductal, calcium hydroxide and the negative control after one, three and eight days. In conclusion, our data indicate that Osteoinductal enhances the mitogenic response of human PDL cells by activation of ERK1/2 and increases cell proliferation, however, it is inferior in comparison to EMD.

Effectiveness of a topical salve (Dynexan) on pain sensitivity and early wound healing following nonsurgical periodontal therapy.

The purpose of the present study was to evaluate clinically the effect of an anaesthetic gel (lidocaine 20 mg/g as active agent) on pain sensitivity and early wound healing following nonsurgical periodontal therapy. A total of 40 patients with chronic periodontitis were enrolled in this randomized, split-mouth, double-blind, placebo-controlled clinical trial. Each subject had 3 sites in each of 2 contra-lateral jaw quadrants with a probing pocket depth (PPD) of > or = 5 mm and bleeding on probing (BOP+). All experimental sites received scaling and root planing without local anesthesia followed by irrigation with sterile saline and assessment of pain sensitivity using a standardized Visual Analogue Scale (VAS). After treatment, the patients randomly received the active or placebo gel into the periodontal pockets and overall pain was again assessed immediately after debridement and after 10, 20 and 30 minutes. The VAS showed a statistically significant (p < or = 0.0001) reduction in reported pain, favoring the active gel over the placebo at all 3 different points in time. After 30 minutes the median VAS score was 0.3 in the Dynexan group as opposed to 1.7 in the placebo-treated group (p < or = 0.0001). In terms of wound healing no differences were found between the test and control sites after 1 week. The results of the study showed that the anaesthetic gel was statistically more effective than the placebo in reducing pain following nonsurgical periodontal therapy. However, in terms of early wound healing no significant differences were seen between the two treatment sites.

Clinical situation of the coronal part of the teeth including restorations types placed prior to endodontic treatment - a retrospective study.

AIM: In the present retrospektive study the situation of the natural crown as well as the restoration types placed prior to endodontic treatment was examined. MATERIALS AND METHODS: A total of 782 teeth from 545 patients (54.3% men; 45.7% women; mean age: 49.9 +/- 12.1 years) were investigated. In addition to the evaluation of the medical history of the patients, x-rays and a clinical investigation were carried out in order to assess the clinical condition of the crown as well as the restoration types. Of special interest were: carious lesions, composite fillings, amalgam, ceramic or gold crowns and/or bridge restorations. RESULTS: 305 of the examined teeth were located in the mandible and 477 in the maxilla. 26.3% of the teeth were anteriors, 31.2% were premolars and 42.5% were molars. 24.2% of the teeth were restored with metal ceramic crowns, 15.1% were restored with gold cast crowns or served as abutment teeth for bridgework; untreated caries was found in 21.1%, and composite fillings were found in 13.7% of the cases. 23.8% of the front teeth, 26.6% of the premolars and 22.6% of the molars showed a metal ceramic restoration. 21% of all carious defects were found in the maxilla as well as in the mandible. CONCLUSIONS: In addition to the high number of untreated carious lesions, the presence of metal ceramics restorations was significantly higher than other restorations types. Carious lesions are main aetiological factors for endodontic measures, but also ceramic restorations including premature contacts have to be considered as causal factors for pulpal irritations.