Publications by authors named "Rok Gašperšič"

18 Publications

  • Page 1 of 1

One-Year Results Assessing the Performance of Prosthetic Rehabilitations in the Posterior Maxilla Supported by 4-mm Extrashort Implants Splinted to 10-mm Implants: A Prospective Case Series.

Int J Oral Maxillofac Implants 2021 Mar-Apr;36(2):371-378

Purpose: The aim of this study was to evaluate the survival and success rates of oral rehabilitations in a shortened maxillary dental arch and expanded maxillary sinus with 4-mm extrashort implants splinted to longer ones.

Materials And Methods: One 10-mm and one/two extrashort 4-mm titanium-zirconium SLActive tissue-level dental implants were inserted into 11 patients with limited vertical bone availability due to an expanded maxillary sinus antrum. Immediately and 6 months after insertion, implant stability resonance frequency analysis (RFA) values were assessed with an Osstell device. Splinted crowns combining 4- and 10-mm implants were supplied to all 11 cases.

Results: In 10 cases, the bone quality was type III, and in one case, type IV. Among 17 4-mm and 11 10-mm implants, the median RFA values were 61 (interquartile ranges [IQR]: 59 to 64) and 66 (IQR: 64 to 72). One 4-mm implant failed to osseointegrate and was removed. After 6 months of healing, secondary-stability measurements of 16 of the remaining 4-mm implants increased to 68 (IQR: 62 to 72) and of 10-mm implants to 78 (IQR: 77 to 80). After 1 year, all (11/11) oral rehabilitations supported by 10-mm (11/11) and 4-mm (16/16) implants were functional. The medians and IQRs of the probing depths (median: 2.8 mm, IQR: 2.3 to 3.1 mm vs median: 2.9 mm, IQR: 2.4 to 3.1 mm) and the crestal bone loss (median: 0.75 mm, IQR: 0 to 0.9 mm vs median: 0.22 mm, IQR: 0 to 0.4 mm) for the 10-mm and 4-mm implants, respectively, were similar.

Conclusion: Rehabilitations with splinted crowns combining 4- and 10-mm implants demonstrated a favorable 1-year performance in a shortened maxillary dental arch.
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http://dx.doi.org/10.11607/jomi.8645DOI Listing
April 2021

The Use of 4-mm Implants Splinted to 10-mm Implants for Replacement of Multiple Missing Teeth in the Posterior Maxilla Region with Expanded Maxillary Sinus. An Observational Cases Series: Patient Characteristics and Preliminary Results.

Int J Periodontics Restorative Dent 2021 Mar-Apr;41(2):261-268

This study aimed to rehabilitate shortened maxillary dental arch with splinted crowns by connecting ultra-short implants with longer ones. In the posterior maxilla of 11 patients, one 10-mm (n = 11) and one or two ultra-short 4-mm (n = 17) dental implants were inserted. The insertion torque was lower than 20 Ncm in 55% of the 10-mm implants and in 94% of the 4-mm implants ( > .05). Median (range) implant stability quotients at the time of insertion and after 6 months were 61 (14 to 72) and 68 (51 to 79), respectively, for 4-mm implants, and 66 (52 to 78) and 78 (60 to 83), respectively, for 10-mm implants ( < .05). One 4-mm implant failed to integrate. All patients were restored with splinted metal-ceramic crowns connecting 4- and 10-mm implants. Median (range) clinical crown/implant ratios of 4-mm and 10-mm implants were 2.79 (1 to 3.66) and 1.06 (0.85 to 1.46), respectively ( < .05). Six months after prosthetic rehabilitation, the median (range) crestal bone loss was 0.3 mm (-0.7 to 1.7 mm) for 4-mm implants and was 0.5 mm (-0.8 to 3.5 mm) for 10-mm implants ( > .05). Splinted crowns combining 4- and 10-mm implants may contribute to a better force distribution in the treatment with ultra-short implant-supported prosthesis in the posterior maxilla.
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http://dx.doi.org/10.11607/prd.4389DOI Listing
April 2021

Systemic azithromycin as an adjunct to scaling and root planing in patients with stage III/IV periodontitis: 12-month results of a randomized controlled clinical trial.

Clin Oral Investig 2021 Mar 30. Epub 2021 Mar 30.

Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, 1000, Ljubljana, Slovenia.

Objectives: To determine whether azithromycin (AZI) as an adjunct to scaling and root planing (SRP), when compared to placebo, decreases the number of sites demonstrating pocket depth (PD) ≥ 5 mm and bleeding on probing (BOP) 12 months post-treatment in stage III/IV periodontitis patients.

Materials And Methods: In a double-blind randomized parallel-arm placebo-controlled trial, 40 stage III/IV periodontitis patients received steps 1 and 2 of periodontal treatment in two sessions within 7 days. Patients then received systemic antibiotic therapy (n = 20; AZI 500 mg/day, 3 days) or placebo (n = 20). Additional instrumentation of residual diseased sites (DS) - sites with PD ≥ 5 mm and BOP - was performed at the 3-, 6- and 9-month follow-ups. The primary outcome variable was the number of DS at the 12-month re-evaluation. Using a multivariate multilevel logistic regression model, the effects of gender, age, antibiotic therapy, presence of Porphyromonas gingivalis or Aggregatibacter actinomycetemcomitans, smoking, tooth being a molar and interdental location were evaluated.

Results: The number of DS after 12 months was similar in the test (median (Me) = 4, interquartile range (IQR) = 0-6) and control (Me = 3, IQR = 1-6.5) groups. Both groups showed substantial but equivalent improvements in periodontal parameters, with no intergroup differences at initially shallow or deep sites. The logistic regression showed a lower odds ratio (OR) for the healing of DS on molars (OR = 0.29; p < 0.001) and in smokers (OR = 0.36; p = 0.048).

Conclusion: Stage III/IV periodontitis patients showed significant but comparable improvements in periodontal parameters and the number of residual DS at the 12-month revaluation regardless of treatment type. This may have been the result of the additional instrumentation received by patients at residual DS in both treatment groups.

Clinical Relevance: Treatment with AZI + SRP provided no additional benefits after 12 months in terms of periodontal parameters or the number of persisting sites with PD ≥ 5 mm + BOP as compared to SRP plus placebo.

Trial Registration: EUDRA-CT: 2015-004306-42; https://www.clinicaltrialsregister.eu/ctr-search/trial/2015-004306-42/SI , registered 17. 12. 2015.
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http://dx.doi.org/10.1007/s00784-021-03906-8DOI Listing
March 2021

Do Differences in Cultivable Subgingival Species Exist between Different Periodontitis Stages and Grades?

Oral Health Prev Dent 2021 ;19(1):15-24

Purpose: To investigate the subgingival microbiological profiles of patients with periodontitis, to determine their stage and grade scores and to evaluate the differences in the microbiota among different stages and grades. Materials and Methods: Sixty-seven (n = 67) periodontitis patients were selected. Periodontitis staging and grading, following the 2018 classification system, were defined. Following a clinical examination, subgingival samples were taken from the deepest periodontal pocket of each quadrant for cultivation, identification and quantification. The prevalence, proportion and counts of nine selected periodontal pathogens were determined, and differences between periodontitis stages III and IV and grades B and C were assessed. Results: All nine cultivable periodontal bacteria were detected, of which the most prevalent was P. intermedia (91.0%) and the least prevalent were E. corrodens (9.0%) and C. ochracea (9.0%). The frequency of detection of the two main target pathogens, A. actinomycetemcomitans and P. gingivalis, was 41.8% and 76.1%, respectively. The prevalence (grade B: 80.6%, grade C: 55.6%, p = 0.035) and total counts (grade B: 19.8 colony forming units - CFU/ml-4 (1.9-52.8); grade C: 4.0 CFU/ml-4 (0.0-26.4); p = 0.022) of F. nucleatum were statistically significantly higher in grade B than in grade C periodontitis patients, whereas the counts of P. gingivalis and A. actinomycetemcomitans were similar between grades and stages. Conclusion: Our study suggests that relevant differences between the various grades of periodontitis exist only in the numbers of F. nucleatum. Prevalence and quantities of other cultivable species between different stages and grades of periodontitis seem to be similar.
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http://dx.doi.org/10.3290/j.ohpd.b875525DOI Listing
January 2021

Influence of adjunctive azithromycin on microbiological and clinical outcomes in periodontitis patients: 6-month results of randomized controlled clinical trial.

BMC Oral Health 2020 09 1;20(1):241. Epub 2020 Sep 1.

Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, 1000, Ljubljana, Slovenia.

Background: Our aim was to determine if azithromycin therapy, as an adjunct to scaling and root planing (SRP), decreases the number of pathobiontic subgingival plaque species and sites demonstrating pocket depth (PD) ≥ 5 mm and bleeding on probing (BOP) 6 months post-treatment.

Methods: In a double-blind randomized parallel-arm placebo-controlled trial, 40 patients received nonsurgical periodontal treatment in two sessions within 7 days. Patients then received systemic antibiotic therapy (n = 20, azithromycin 500 mg/day for 3 days) or placebo (n = 20). Pooled microbiologic samples were taken before and 6 months after therapy and analysed by established culture methods. The primary outcome variable was the number of sites with PD ≥ 5 mm and BOP at the 6-month re-evaluation. Using multivariate multilevel logistic regression, the effects of gender, age, antibiotic therapy, presence of P. gingivalis or A. actinomycetemcomitans, smoking, tooth being a molar and interdental location were evaluated.

Results: The number of sites with PD ≥ 5 mm and BOP after 6 months was similar in the test (Me = 4, IQR = 0-11) and control (Me = 5, IQR = 1-22) group. Adjunctive azithromycin treatment, compared to SRP alone, resulted in more frequent eradication of A. actinomycetemcomitans (p = 0.013) and C. rectus (p = 0.029), decreased proportion (p = 0.006) and total counts (p = 0.003) of P. gingivalis, and decreased proportion of C. rectus (p = 0.012). Both groups showed substantial but equivalent improvements in periodontal parameters, with no intergroups differences at initially shallow or deep sites. The logistic regression showed a lower odds ratio for healing of diseased sites on molars (OR = 0.51; p <  0,001).

Conclusion: Despite significant changes in numbers of A. actinomycetemcomitans, P. gingivalis and C. rectus, patients with periodontitis do not benefit from adjunctive systemic azithromycin in terms of number of persisting sites with PD ≥ 5 mm and BOP.

Trial Registration: EUDRA-CT: 2015-004306-42; https://www.clinicaltrialsregister.eu/ctr-search/trial/2015-004306-42/SI , registered 17. 12. 2015.
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http://dx.doi.org/10.1186/s12903-020-01209-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7465355PMC
September 2020

3D computer-aided treatment planning in periodontology: A novel approach for evaluation and visualization of soft tissue thickness.

J Esthet Restor Dent 2020 Jul 25;32(5):457-462. Epub 2020 Jun 25.

Department of Restorative Dentistry and Endodontics, University Medical Centre, Ljubljana, Ljubljana, Slovenia.

Objective: Current approaches for soft tissue thickness evaluation and visualization still represent a challenge for full extent evaluation and visualization. The aim of this clinical technique article is to introduce a novel approach for comprehensive visualization and precise evaluation of oral soft tissue thickness utilizing a fusion of optical 3D and cone-beam computed tomography (CBCT) images.

Clinical Considerations: 3D models of the maxilla were obtained by CBCT imaging and intraoral scanning. The CBCT images were reconstructed to standard tessellation language (STL) file format models by segmentation of teeth and bone using implants planning software. 3D soft tissues and teeth models were obtained by intraoral scanning and were exported in STL file format as well. 3D multimodal models were then superimposed using best-fit matching on teeth. Soft tissue thickness was then visualized and evaluated with a 3D color-coded thickness map of gingival and palatal areas created by surface comparison of both 3D models. Additionally, threshold color-coding was used to increase comprehensibility. Palatal areas were further visualized and evaluated for the optimal donor site.

Conclusions: A novel approach for 3D evaluation and visualization of masticatory mucosa thickness presents all available 3D data in a comprehensible, "clinician-friendly" manner, using threshold regions and clinically relevant views.

Clinical Significance: Proposed approach could provide comprehensive presurgical treatment planning in periodontal plastic surgery and implantology without additional invasive procedures for the patient, resulting in more predictable treatment, improved outcomes, and reduced risk for complications.
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http://dx.doi.org/10.1111/jerd.12614DOI Listing
July 2020

Split-Mouth Comparison of Coronally Advanced Flap with Connective Tissue Graft or Collagen Matrix for Treatment of Isolated Gingival Recessions.

Int J Periodontics Restorative Dent 2019 May/Jun;39(3):439-446

Collagen matrices (CMs) could be used instead of connective tissue grafts (CTGs) for treatment of gingival recession (GR). The authors aimed to compare clinical outcomes after treatment of isolated GR affecting both maxillary canines of 10 patients (n = 10) with CM (OsteoBiol Derma) or CTG in conjunction with coronally advanced flap. After 12 months, CM and CTG showed complete correction in 7/10 and 10/10 of sites, respectfully, and percentage of root coverage was 85% ± 24% and 100%, respectively. For treatment of isolated GR, CM is a viable alternative to CTG.
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http://dx.doi.org/10.11607/prd.3562DOI Listing
October 2019

Occurrence of Dental Injuries and Periodontal Complications in Tongue-piercing Jewellery Users.

Oral Health Prev Dent 2017;15(3):293-297

Purpose: Tongue piercing (TP) has been gaining in popularity, mainly among adolescents and young adults, and there has been a corresponding increase in reports of dental injury and adverse effects on periodontal tissue due to TP jewellery. The purpose of this study was to assess the type and prevalence of dental injury and periodontal complications in a group of Slovenian adolescents and young adults with TP in comparison with a control group.

Materials And Methods: This case-control study included 17 subjects with TP (study group) and 28 subjects without TP (control group). Subjects were clinically examined for dental injuries, as classified according to Andreasen. Periodontal complications were evaluated using an estimation of clinical attachment loss (CAL) and gingival recession (GR). Differences in categorical variables were analyzed using the chi-squared or Fisher's exact test as appropriate. Differences between the groups in numerical variables were analyzed with the Mann-Whitney U-test. A multiple logistic regression model was built to test the association between dental injuries and TP when controlling for cofounders, namely age and gender of study participants. The significance level was set at α = 0.05 (two-tailed).

Results: Subjects with TP had 12.2 higher odds of dental injury (CI = 2.2-67.7, p = 0.004) compared with subjects without TP. Enamel fractures were more prevalent in the study group (p = 0.002). Frequencies of other dental injuries in the two groups were similar. GR was significantly associated with TP (p = 0.008), while differences in CAL between the groups were not statistically significant.

Conclusion: Subjects with tongue piercing had more dental injuries and gingival recession.
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http://dx.doi.org/10.3290/j.ohpd.a38530DOI Listing
November 2017

A Cytolethal Distending Toxin Variant from Aggregatibacter actinomycetemcomitans with an Aberrant CdtB That Lacks the Conserved Catalytic Histidine 160.

PLoS One 2016 14;11(7):e0159231. Epub 2016 Jul 14.

Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.

The periodontopathogen Aggregatibacter actinomycetemcomitans synthesizes several virulence factors, including cytolethal distending toxin (CDT). The active CDT holoenzyme is an AB-type tripartite genotoxin that affects eukaryotic cells. Subunits CdtA and CdtC (B-components) allow binding and intracellular translocation of the active CdtB (A-component), which elicits nuclear DNA damage. Different strains of A. actinomycetemcomitans have diverse virulence genotypes, which results in varied pathogenic potential and disease progression. Here, we identified an A. actinomycetemcomitans strain isolated from two patients with advance chronic periodontitis that has a regular cdtABC operon, which, however, codes for a unique, shorter, variant of the CdtB subunit. We describe the characteristics of this CdtBΔ116-188, which lacks the intact nuclear localisation signal and the catalytic histidine 160. We show that the A. actinomycetemcomitans DO15 isolate secretes CdtBΔ116-188, and that this subunit cannot form a holotoxin and is also not genotoxic if expressed ectopically in HeLa cells. Furthermore, the A. actinomycetemcomitans DO15 isolate is not toxic, nor does it induce cellular distention upon infection of co-cultivated HeLa cells. Biological significance of this deletion in the cdtB remains to be explained.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0159231PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4945079PMC
July 2017

EFP Delphi study on the trends in Periodontology and Periodontics in Europe for the year 2025.

J Clin Periodontol 2016 06 10;43(6):472-81. Epub 2016 May 10.

University of Granada, Granada, Spain.

Aim: The aim was to assess the potential trends in Periodontology and Periodontics in Europe that might be anticipated by the year 2025, using the Delphi method.

Material And Methods: The expert opinion of 120 experts was sought through the use of an open-ended questionnaire, developed by an advisory group, containing 40 questions concerning the various trends in periodontology.

Results: The experts (113 responders) expect a stabilization of the prevalence of periodontitis, both for the chronic as well as the aggressive cases, but an increase in implant-related diseases up to the year 2025. Concurrently, the importance of implants is seen to be increasing. They foresee an increased demand for postgraduate periodontology and implantology training. This is mirrored in an increase in publications for implant dentistry and increase in demand and need for training. Concerning the patients, better-informed individuals seeking more routine check-ups are expected.

Conclusion: A continued need for specialized periodontists, but also well trained dental practitioners is foreseen for next decade in Europe. Apart from periodontology they will be increasingly exposed to and trained in implant dentistry.
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http://dx.doi.org/10.1111/jcpe.12551DOI Listing
June 2016

Toll-like receptor 4 expression in trigeminal neurons is increased during ligature-induced periodontitis in rats.

J Periodontol 2014 Jan 9;85(1):170-7. Epub 2013 May 9.

Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.

Background: Periodontitis, activated by oral bacteria and orchestrated by innate immune response, is regulated by primary nociceptive neurons, which are generally considered to have small- to medium-sized perikaryons. Bacterial byproducts (e.g., lipopolysaccharides) activate primary nociceptive neurons directly through Toll-like receptors (TLRs). Therefore, this study aims to morphometrically characterize rat trigeminal neurons, which express TLR4, and to investigate the changes in the TLR4 expression in neurons during periodontal inflammation.

Methods: Trigeminal neurons innervating gingivomucosa were identified by application of the retrograde tracer hydroxystilbamidine into the gingival sulcus of the maxillary molar in 14 rats. Periodontitis was induced by ligature around the same molar in seven rats. TLR4 expression was investigated by immunohistochemistry on paraffin sections of the trigeminal ganglia (TG). Semiquantitative method was used to identify the intensity of TLR4 expression.

Results: In the control group without the ligatures, TLR4 was detected in 19% of the neurons in the maxillary region of TG and in 29% of neurons innervating gingivomucosa. Expression of TLR4 was more frequent and intensive in small- to medium-sized neurons than in large-sized neurons. One week after ligature-induced periodontitis, the percentage of TLR4-positive neurons in the maxillary region and among the neurons innervating inflamed gingivomucosa significantly increased statistically to 32% and 41%, respectively.

Conclusions: TLR4 is predominantly, but not exclusively, expressed in smaller trigeminal nociceptive neurons in the rat. Experimental periodontitis upregulates TLR4 expression in the trigeminal neurons. The hypothesis that bacterial byproducts regulate the pathogenesis of periodontitis by activation of trigeminal nociceptors through TLR4 should be explored.
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http://dx.doi.org/10.1902/jop.2013.130039DOI Listing
January 2014

Dental pulp and gingivomucosa in rats are innervated by two morphologically and neurochemically different populations of nociceptors.

Arch Oral Biol 2013 Jul 11;58(7):788-95. Epub 2013 Feb 11.

Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 2, 1000 Ljubljana, Slovenia.

Objectives: Difference in phenotypes of sensory neurons innervating dental pulp or gingivomucosa may be responsible for intense pain sensations in pulpitis in contrast to relatively painless chronic periodontitis. Therefore, we classified these neurons according to their size and two neurochemical characteristics of nociceptors, their TrkA expression and isolectin IB4 binding.

Design: In rats (n=6) fluorescent tracers Fluorogold and TrueBlue were simultaneously applied into the standard-sized tooth cavity and nearby gingival sulcus, respectively. After the fluorescence on paraffin trigeminal ganglia (TG) sections was identified and photographed, immunohistochemistry for TrkA expression and IB4 binding was performed on the same sections.

Results: The average sizes of TG neurons projecting to the gingivomucosa and dental pulp were 894±441μm(2) and 1012±381μm(2), respectively. The proportions of small-sized gingival and pulpal neurons were 14% and 5%, respectively (p<0.05). The proportions of TrkA-positive neurons among all gingival or pulpal neurons were 76% and 86%, respectively (p<0.05). Among all gingival or pulpal neurons the proportions of IB4-positive neurons were 46% and 3% (p<0.001), respectively, and the majority of them were small-medium sized.

Conclusions: Dental pulp and gingivomucosa are richly innervated by nociceptive TrkA-expressing neurons. However, while great majority of pulpal neurons are larger NGF-dependent A-fibre nociceptors without affinity to bind IB4, almost half of the gingival neurons are smaller IB4 binding C-fibre nociceptors. The difference in phenotype of sensory neurons might partially explain the different sensitivity of both tissues during normal and pathological conditions.
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http://dx.doi.org/10.1016/j.archoralbio.2013.01.006DOI Listing
July 2013

Unilateral ligature-induced periodontitis influences the expression of neuropeptides in the ipsilateral and contralateral trigeminal ganglion in rats.

Arch Oral Biol 2008 Jul 17;53(7):659-65. Epub 2008 Mar 17.

Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.

Objectives: Expression of neuronal neuropeptides in inflammatory conditions is altered. The changes in expression of substance P (SP) and calcitonin gene-related peptide (CGRP) in ipsilateral and contralateral trigeminal ganglion (TG) neurons were investigated by immunohistochemistry one week after unilateral ligature-induced periodontitis in rats.

Design: A retrograde nerve tracer Fluorogold (FG) was applied into the gingival sulcus of the second maxillary molar to identify the neurons in TG that specifically innervate the inflamed gingivomucosa. In addition, neurons from the corresponding maxillary and the adjacent mandibular-ophthalmic regions in TG were analysed.

Results: Statistically significantly higher frequencies of CGRP-positive neurons, regardless of their size, were found in TG ipsilateral to the periodontitis (83% and 73% in FG-labelled and maxillary regions, respectively) than in the control group without periodontitis (52% and 42% in FG-labelled and maxillary regions, respectively). The frequency of small FG-labelled SP-positive neurons in the ipsilateral TG (60%) was significantly higher than in the control TG (25%). In the contralateral TG the frequency of CGRP-positive neurons in maxillary region (66%) was significantly higher than in the control group. Surprisingly, the number of SP-positive neurons in all regions of contralateral TG decreased when compared to control and ipsilateral TGs.

Conclusions: Taken together, these results implicate a role of neurogenic component in the pathogenesis of periodontitis. The contralateral response in the TG could be mediated through the transmedian neurological pathways crossing in the trigeminal nuclear complex or through the systemic inflammatory reaction and the activation of the so called "neuro-immune axis".
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http://dx.doi.org/10.1016/j.archoralbio.2008.01.017DOI Listing
July 2008

Expression of TrkA receptor for neurotrophins in trigeminal neurons innervating the rat gingivomucosal tissue.

Neurosci Lett 2007 May 30;418(3):253-6. Epub 2007 Mar 30.

Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.

The purpose of this study was to characterize and evaluate the expression of TrkA receptor in trigeminal ganglion (TG) neurons that innervate the rat gingivomucosal tissue. A retrograde nerve tracer Fluorogold (FG) was injected into the gingiva (group 1) or applied into the gingival sulcus (group 2) of the first right maxillary molar to identify the neurons in TG that innervate the gingivomucosa. After 10 days TG were dissected and FG fluorescence in neurons was observed under UV light microscope. To draw a comparison, approximately 1000 neurons per ganglion from the entire TG (group 3) and approximately 350 neurons per ganglion from the maxillary region in TG (group 4), were analyzed. Expression of TrkA receptor in TG neurons was investigated by immunohistochemistry. About 70% of neurons in groups 1 and 2 contained TrkA receptor, which was statistically significantly more than in groups 3 (41%) and 4 (38%). FG-labeled TrkA-immunopositive neurons were predominantly small or medium-sized (less than 1200microm(2)). However, the neurons innervating the rat gingivomucosa were on average larger than the neurons in the entire TG or in the maxillary region. In conclusion, the majority of neurons in TG that innervate the rat gingivomucosa are small or medium-sized, contain TrkA receptor and are most probably nociceptive.
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http://dx.doi.org/10.1016/j.neulet.2007.03.060DOI Listing
May 2007

Identification and neuropeptide content of trigeminal neurons innervating the rat gingivomucosal tissue.

Arch Oral Biol 2006 Aug 17;51(8):703-9. Epub 2006 Apr 17.

Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.

Objectives: The purpose of this study was to identify and characterise the neuropeptide content and the size of trigeminal ganglion (TG) neurons innervating the rat gingivomucosal tissue.

Design: Retrograde nerve tracer Fluorogold (FG) was injected into the gingiva (group 1, n=5) or applied into the gingival sulcus (group 2, n=5) of the first right maxillary molar. After 10 days, the ganglia were dissected and FG fluorescence was observed under UV light microscope. Expression of calcitonin gene-related peptide (CGRP) and substance P (SP) in FG-labelled neurons was investigated by immunohistochemistry. Cross-sectional areas of neuron cell bodies containing FG were determined. As a control group, approximately 1000 neuron cell bodies representing the entire TG neuron population was evaluated in five trigeminal ganglia.

Results: In group 1, the percentages of neurons containing CGRP (median 63%, range 48-72%) and SP (median 64%, range 54-64%) were significantly greater than in the control group (CGRP: median 43%, range 42-47% and SP: median 23%, range 21-27%). In group 2, only the percentage of neurons containing SP (median 50%, range 40-56%) was significantly greater than in the control group. FG-labelled neurons were predominantly small or medium sized (less than 1200 microm2). The neurons in the group 1 were significantly smaller than in group 2. In both experimental groups, immunopositive neurons were significantly smaller than immunonegative neurons.

Conclusions: The majority of neurons in TG that innervate the rat gingivomucosa are small or medium sized and contain CGRP and SP.
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http://dx.doi.org/10.1016/j.archoralbio.2006.02.007DOI Listing
August 2006

In vivo administration of recombinant TNF-alpha promotes bone resorption in mice.

J Periodontal Res 2003 Aug;38(4):446-8

Department of Oral Medicine and Periodontology, Institute of Histology and Embryology, Faculty of Medicine, University of Ljubljana and Clinical Institute of Clinical Chemistry and Biochemistry, Clinical Centre, Ljubljana, Slovenia.

Background: In vitro studies demonstrated that proinflammatory cytokine tumor necrosis factor alpha (TNF-alpha) modulates bone metabolism.

Objective: The aim of our study was to confirm the ability of TNF-alpha to induce osteoclastogenesis and bone resorption in an in vivo experiment, with the use of calvarial model in mice.

Materials And Methods: Twenty C57-Black mice were divided into four groups with five animals in each. The first group was infused subcutaneously on their back with recombinant mouse (rm) TNF-alpha via osmotic minipumps for 3 d, the second group was similarly infused with phosphate-buffered saline (PBS), the third group was infused with rmTNF-alpha to the region above the parietal bone and the fourth group with PBS in the same manner. Number of osteoclasts on parietal bone was determined morphometrically. Serum calcium and phosphates were monitored colorimetrically.

Results: Serum calcium level and number of osteoclasts on parietal bone were significantly greater after infusion of rmTNF-alpha above the parietal bone, whereas after subcutaneous delivery these parameters were similar to the control group.

Conclusion: We are concluding that TNF-alpha has the ability to change the bone metabolism in a paracrine manner only.
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http://dx.doi.org/10.1034/j.1600-0765.2003.00662.xDOI Listing
August 2003

Influence of subcutaneous administration of recombinant TNF-alpha on ligature-induced periodontitis in rats.

J Periodontal Res 2003 Apr;38(2):198-203

Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Slovenia.

Proinflammatory cytokine tumor necrosis factor alpha (TNF-alpha) was found in inflamed periodontal tissues and many studies pointed to its significant role in development of periodontal disease. In this study, the influence of subcutaneously administered recombinant human TNF-alpha (rhTNF-alpha) on inflammatory reaction and periodontal breakdown in rats was analyzed during experimental periodontitis, induced by placing silk ligatures around the maxillary right second molar tooth. The rats were divided into two groups with five animals in each; the first group was infused subcutaneously with rhTNF-alpha via osmotic pumps for 2 weeks and the second group was infused with phosphate-buffered saline (PBS) in the same manner. Inflammatory reaction and periodontal breakdown was evaluated morphometrically on hematoxylin and eosin stained sections. Serum ionized calcium and inorganic phosphates were monitored colorimetrically. Serum calcium and phosphate levels were similar in rats receiving rhTNF-alpha and PBS. Ligation resulted in accelerated periodontal breakdown, while subcutaneous rhTNF-alpha administration by itself had no significant effect. Combined effect of subcutaneous rhTNF-alpha administration and ligation resulted in a significantly greater inflammatory reaction and periodontal breakdown then either treatment alone. We concluded that the subcutaneous administration of rhTNF-alpha accelerates the progression of experimental periodontitis in rats.
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http://dx.doi.org/10.1034/j.1600-0765.2003.01395.xDOI Listing
April 2003

Influence of restraint stress on ligature-induced periodontitis in rats.

Eur J Oral Sci 2002 Apr;110(2):125-9

Department of Oral Medicine and Periodontology, Faculty of Medicine, University of Ljubljana, Slovenia.

The influence of stress on periodontal breakdown in Wistar rats was analyzed during experimental periodontitis, induced by placing silk ligatures around the maxillary right second molar teeth. The rats were divided into three groups with 10 animals in each; the first group was exposed to restraint stress for 12 h d(-1) for a period of 4 wk; the second group was exposed to restraint stress for 2.5 h d(-1) for a period of 4 wk; the third group served as a control group. Ligation for 4 wk resulted in an accelerated periodontal degradation, whereas the restraint stress by itself had no significant effect. Combined stress and ligation resulted in a significantly higher attachment loss and alveolar bone resorption than either treatment alone, while no differences were seen between the two stress regimens. After 4 wk, a reduced body weight was found in both restrained groups of rats and a reduced weight of the thymus in the rats restrained for 12 h d(-1), while no changes were observed in the weight or composition of the suprarenal glands. We conclude that stress alone does not result in periodontal disease but may modulate the pathophysiological processes of already present periodontal inflammation, resulting in accelerated degradation of periodontal tissues.
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http://dx.doi.org/10.1034/j.1600-0722.2002.11153.xDOI Listing
April 2002