Air powder waterjet technology using erythritol or glycine powders in periodontal or peri-implant prophylaxis and therapy: A consensus report of an expert meeting

OBJECTIVES

To attain a collective expert opinion on the use of air powder waterjet technology (APWT) with erythritol and glycine powders in the prophylaxis and therapy of periodontal and peri-implant diseases.

MATERIAL AND METHODS

In the first step, a modified one-round online Delphi survey including 44 five-point Likert scale questions was conducted among a group of 10 expert clinicians and researchers with thorough knowledge and experience in this topic. In the second step, the single questions and the survey results were discussed during a meeting, and consensus statements were formulated, respectively.

RESULTS

An agreement was reached on most items, especially opinions supporting glycine and erythritol powders as favorable with respect to efficiency, safety, and comfort. More scientific evidence is needed to support the improvement in clinical attachment on teeth and implants, especially when APWT with erythritol is used. In addition, APWT needs more long-term evaluation and studies in terms of microbiome/microbiological effects as well as effects on the inflammatory response on natural teeth and implants, also in light of a guided biofilm therapy concept.

CONCLUSIONS

In line with the expert opinions and supported by the evidence, it was concluded that the use of APWT with erythritol and glycine powders in nonsurgical periodontal and peri-implant therapy and prophylaxis is patient compliant and efficient.

Clinical, immunological, and microbiological analysis of the association between periodontitis and COVID-19: a case-control study

PURPOSE

Periodontitis and coronavirus disease (COVID-19) share risk factors and activate similar immunopathological pathways, intensifying systemic inflammation. This study investigated the clinical, immunological and microbiological parameters in individuals with COVID-19 and controls, exploring whether periodontitis-driven inflammation contributes to worsening COVID-19 endpoints.

METHODS

Case (positive RT-PCR for SARS-CoV-2) and control (negative RT-PCR) individuals underwent clinical and periodontal assessments. Salivary levels of TNF-α, IL-6, IL-1β, IL-10, OPG, RANKL, neutrophil extracellular traps, and subgingival biofilm were analyzed at two timepoints. Data on COVID-19-related outcomes and comorbidity information were evaluated from medical records.

RESULTS

Ninety-nine cases of COVID-19 and 182 controls were included for analysis. Periodontitis was associated with more hospitalization (p = 0.009), more days in the intensive care unit (ICU) (p = 0.042), admission to the semi-ICU (p = 0.047), and greater need for oxygen therapy (p = 0.042). After adjustment for confounders, periodontitis resulted in a 1.13-fold increase in the chance of hospitalization. Salivary IL-6 levels (p = 0.010) were increased in individuals with COVID-19 and periodontitis. Periodontitis was associated with increased RANKL and IL-1β after COVID-19. No significant changes were observed in the bacterial loads of the periodontopathogens Porphyromona gingivalis, Aggregatibacter actinomycetemcomitans, Tanerella forsythia, and Treponema denticola.

CONCLUSIONS

Periodontitis was associated with worse COVID-19 outcomes, suggesting the relevance of periodontal care to reduce the burden of overall inflammation. Understanding the crosstalk between SARS-CoV-2 infection and chronic conditions such as periodontitis that can influence disease outcome is important to potentially prevent complications of COVID-19.

DIETARY SUPPLEMENTATION OF OMEGA-3 FATTY ACIDS COULD BE USED AS AN ADJUNCT THERAPY TO NONSURGICAL PERIODONTAL TREATMENT

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Castro Dos Santos NC, Furukawa MV, Oliveira-Cardoso I, Cortelli JR, Feres M, Van Dyke T, Rovai ES. Does the use of omega-3 fatty acids as an adjunct to nonsurgical periodontal therapy provide additional benefits in the treatment of periodontitis? A systematic review and meta-analysis. J Periodontal Res. 2022 Jun;57(3):435-447. doi: 10.1111/jre.12984. Epub 2022 Mar 3. PMID: 35243637.

SOURCE OF FUNDING

This study was funded by São Paulo Research Foundation (FAPESP) under awards 2020/05875-9 (to NCCS), 2020/05874-2 (to MF), and 2019/14846-5 (to ESR).

TYPE OF STUDY/DESIGN

Systematic review and meta-analysis.

Role of Dietary Fibre in Managing Periodontal Diseases-A Systematic Review and Meta-Analysis of Human Intervention Studies

BACKGROUND

Periodontitis is a chronic multifactorial inflammatory disease, that leads to tooth loss and is associated with other systemic diseases. The role of dietary fibre in the prevention and management of periodontal diseases is not well understood. The objective of this systematic review and meta-analysis was to assess how an intake of dietary fibre affects periodontal diseases in humans and any concomitant effects on systemic inflammation.

METHODOLOGY

Human interventional studies investigating the effects of oral fibre intake on various clinical parameters of periodontal diseases were included. Search strategy with MeSH and free-text search terms was performed on the following database: CINAHL Complete, EMBASE, MEDLINE, SciVerse Scopus®, and Web of Science Core Collection on 21 October 2021 and updated on 19 February 2023 to identify relevant studies. Articles were filtered using the Covidence© web-based platform software. Data were pooled using random effects meta-analysis.

RESULTS

From all databases, a total of 19,971 studies were obtained. Upon title and abstract screening, 101 studies were included for full-text screening. Upon full-text screening, six studies were included for analysis. Of these, five were randomised controlled trials, and one was a sequential feeding trial involving fibre-rich daily diet for a 4-8 weeks period. Fibre-rich dietary intervention significantly reduced Clinical Attachment Loss/Level by 0.48 mm/tooth (95% CI, -0.63 to -0.33, p < 0.001), Bleeding On Probing by 27.57% sites/tooth (95% CI -50.40 to -4.74, p = 0.02), Periodontal Inflamed Surface Area by 173.88 mm2 (95% CI -288.06 to -59.69, p = 0.003), Plaque Index by 0.02 (95% CI -0.04 to -0.00, p = 0.04), and Gingival Index by 0.41 (95% -0.67 to -0.16, p= 0.002). A non-significant reduction was observed for Probing Depth (-0.17 mm/tooth; 95% CI, -0.37 to 0.02, p = 0.09).

CONCLUSIONS

Fibre-rich dietary interventions are associated with a reduction of clinical and particularly inflammatory markers of periodontal diseases. This shows a promising effect of dietary fibre as an intervention for inflammatory conditions like periodontal diseases.

Impact of health and lifestyle food supplements on periodontal tissues and health

According to the new classification, periodontitis is defined as a chronic multifactorial inflammatory disease associated with dysbiotic biofilms and characterized by progressive destruction of the tooth-supporting apparatus. This definition, based on the current scientific evidence, clearly indicates and emphasizes, beside the microbial component dental biofilm, the importance of the inflammatory reaction in the progressive destruction of periodontal tissues. The idea to modulate this inflammatory reaction in order to decrease or even cease the progressive destruction was, therefore, a logical consequence. Attempts to achieve this goal involve various kinds of anti-inflammatory drugs or medications. However, there is also an increasing effort in using food supplements or so-called natural food ingredients to modulate patients' immune responses and maybe even improve the healing of periodontal tissues. The aim of this chapter of Periodontology 2000 is to review the evidence of various food supplements and ingredients regarding their possible effects on periodontal inflammation and wound healing. This review may help researchers and clinicians to evaluate the current evidence and to stimulate further research in this area.

The efficacy of the adjunct use of subgingival air-polishing therapy with erythritol powder compared to conventional debridement alone during initial non-surgical periodontal therapy

Aim

To assess the efficacy of the adjunct use of a subgingival erythritol powder air‐polishing device (EPAP) in comparison to conventional subgingival instrumentation alone during initial non‐surgical periodontal therapy.

Materials and Methods

Twenty‐one patients with generalized Stages 2 and 3 grade B periodontitis were included in this single centre, single blinded, split‐mouth, randomized clinical trial. Teeth on the control side were treated with conventional hand and ultrasonic instrumentation, while those on the contralateral test side was treated using EPAP as adjunct to conventional subgingival instrumentation with hand and ultrasonic instruments. Three months after initial instrumentation, persisting pockets of ≥4 mm were re‐treated, in both control and test sides, again with the respective treatment approach—subgingival instrumentation alone on control, and subgingival instrumentation + EPAP on test side. Clinical parameters such as probing pocket depth (PPD), bleeding on probing, and relative attachment level were recorded at baseline and 3 and 6 months following the initial instrumentation. Subgingival plaque samples were collected at baseline, immediately post surgery, as well as at 1 week, 1 month, 3 months, and 6 months after initial instrumentation.

Results

In the test group after 6 months, a significantly larger number of initially deep pockets (PPD ≥ 5.5 mm) were reduced to shallow (PPD ≤ 3.4 mm), and a larger attachment gain was observed. No statistically significant microbiological differences could be found between test and control group.

Conclusions

The results of the present study indicate that the adjunct use of subgingival airflow therapy with EPAP during initial non‐surgical periodontal therapy might be beneficial in initially deep pockets (PPD ≥ 5.5 mm).

Peri-Implant Health and the Knowing-Doing Gap—A Digital Survey on Procedures and Therapies

Objectives: Peri-implant tissue maintenance and treatment is becoming a serious challenge in implantology. With increasing numbers of implants being placed, more cases of peri-implant mucositis and peri-implantitis is seen. A digital survey on peri-implant disease management was issued to experts in periodontology and implantology to identify the tools and procedures most commonly used today to treat peri-implant diseases and successfully manage peri-implant health. The primary aim was to assess whether there is consensus in the choice of treatment to manage peri-implant diseases and to prevent their recurrence once treated. The secondary aim was to obtain insight into future protocols and /or devices, and the research and development needed.

Materials and Methods: Participants in this digital survey were professionals specialising in periodontology, oral surgery, and implant dentistry. The questionnaire included both a series of closed- and open-ended questions. A total of 16 countries participated. The survey was sent by e-mail to 70 individuals, 66 received the survey and 37 of receivers responded, two of the participants were excluded due to insufficient filling of the survey. In the end 35 respondents completed the survey.

Results: Respondents agree that the efficacy of mechanical and chemical decontamination of implant surfaces needs to be improved and better documented. It is a common opinion that the current remedies, mostly adapted from periodontal practises, do not provide effective and reliable clinical outcomes when treating peri-implant ailments. There is a general agreement amongst experts that regularly scheduled (3–6-month intervals) maintenance treatments are essential for maintaining peri-implant health in patients experiencing implant complications. Respondents are also concerned about unnecessary use of systemic antibiotics for managing peri-implant health.

Conclusion: Regardless of agreements in parts, there was no observed consensus on the most effective treatment options for treating peri-implantitis. The experts all agree it is an urgent need for well-designed, long-term follow-up randomised and controlled clinical trials comparing interventions to provide an evidence-based strategy for peri-implant health management.

Stress in Parents of Children With Genetically Determined Leukoencephalopathies: A Pilot Study

Genetically determined leukoencephalopathies comprise a group of rare inherited white matter disorders. The majority are progressive diseases resulting in early death. We performed a cross-sectional pilot study including 55 parents from 36 families to assess the level of stress experienced by parents of patients with genetically determined leukoencephalopathies, aged 1 month to 12 years. Thirty-four mothers and 21 fathers completed the Parenting Stress Index-4th Edition. One demographic questionnaire was completed per family. Detailed clinical data was gathered on all patients. Statistical analysis was performed with total stress percentile score as the primary outcome. Mothers and fathers had significantly higher stress levels compared with the normative sample; 20% of parents had high levels of stress whereas 11% had clinically significant levels of stress. Mothers and fathers had comparable total stress percentile scores. We identified pediatric behavioral difficulties and gross motor function to be factors influencing stress in mothers. Our study is the first to examine parental stress in this population and highlights the need for parental support early in the disease course. In this pilot study, we demonstrated that using the Parenting Stress Index-4th Edition to assess stress levels in parents of patients with genetically determined leukoencephalopathies is feasible, leads to valuable and actionable results, and should be used in larger, prospective studies.

Injectable porcine bone demineralized and digested extracellular matrix-PEGDA hydrogel blend for bone regeneration

Extracellular matrix (ECM) has a major role in the structural support and cellular processes of organs and tissues. Proteins extracted from the ECM have been used to fabricate different scaffolds for tissue engineering applications. The aims of the present study were to extract, characterize and fabricate a new class of hydrogel with proteins isolated from pig bone ECM and combine them with a synthetic polymer so it could be used to promote bone regeneration. Porcine bone demineralized and digested extracellular matrix (pddECM) containing collagen type I was produced, optimized and sterilized with high pressurized CO₂ method. The pddECM was further blended with 20% w/v polyethylene glycol diacrylate (PEGDA) to create an injectable semi interpenetrating polymer network (SIPN) scaffold with enhanced physicochemical properties. The blend tackled the shortfall of natural polymers, such as lack of structural stability and fast degradation, preserving its structure in more than 90% after 30 days of incubation; thus, increasing the material endurance in a simulated physiological environment. The manufactured injectable hydrogel showed high cytocompatibility with hOb and SaOs-2 cells, promoting osteogenic proliferation within 21 days of culture. The hydrogel had a high compression modulus of 520 kPa, low swelling (5.3 mg/mg) and millimetric volume expansion (19.5%), all of which are favorable characteristics for bone regeneration applications.

The efficacy of air polishing devices in supportive periodontal therapy: A systematic review and meta-analysis

OBJECTIVE

This systematic review analyzes existing literature on the clinical efficacy of air polishing devices (APDs), discussing the evidence-based data available for justifying their use as an alternative to conventional periodontal debridement in supportive periodontal therapy. The main objective of the review was to assess whether APD was as equally efficient or superior in obtaining successful treatment outcomes when compared with conventional methods.

DATA SOURCES

Following PRISMA guidelines, a systematic literature search of articles in English, up to December 2016, was conducted using PubMed, Cochrane, and Medline. Relevant articles were selected based on specific criteria. Seven studies were selected for the final assessment. One more study was added after a manual search of the literature. Due to considerable heterogeneity in study designs and outcome variables measured, only clinical parameters (probing depth, bleeding on probing, and clinical attachment level) were selected for meta-analysis.

CONCLUSION

The studies selected for this systematic review provide some evidence that APDs as monotherapy could be an alternative to conventional debridement of single- and multi-rooted teeth with no furcation involvement, during supportive periodontal therapy. Comparing clinical and microbiologic outcomes, APDs seem to be as effective as conventional treatments. The primary advantage for the use of APDs in supportive periodontal therapy seems to be their ability to efficiently remove biofilm, without causing damage to the periodontal soft tissues or tooth and root structure. There may also be an advantage regarding patient comfort and time consumed.

Automatic detection of periodontitis using intra-oral images

Periodontitis is a chronic inflammatory disease of the supportive tissues and bone surrounding the teeth. In severe cases, it can consequently lead to tooth loss. This disease is most prevalent in rural and remote communities where regular dental visits are limited. Hence, there's a need for a periodontal screening tool for use by allied health professionals outside of dental clinics to detect periodontitis for early referral and intervention. In this paper two algorithms have been proposed and applied on two independently collected datasets in Germany and Australia with 20 and 24 participating subjects respectively; in the first algorithm, intra-oral images of before periodontitis treatment have been considered as diseased subjects and the images of after treatment have been considered as healthy subjects. Using the histogram of pixel intensity as our classification feature, the healthy and diseased subjects have been classified with an accuracy of 66.7%. In the second algorithm, using the difference between the histograms as our classification features, images of "before" and "after" treatment have been classified with an accuracy of 91.6%. If used in a smart phone application, the first algorithm can help people with limited access to dental clinics to be screened for periodontitis by allied health professionals in any healthcare setting. The second algorithm may be useful in helping non-dental personnel to monitor the progress of periodontal treatment.

Uncovering the balance of forces driving microtubule aster migration in C. elegans zygotes

Microtubule asters must be positioned precisely within cells. How forces generated by molecular motors such as dynein are integrated in space and time to enable such positioning remains unclear. In particular, whereas aster movements depend on the drag caused by cytoplasm viscosity, in vivo drag measurements are lacking, precluding a thorough understanding of the mechanisms governing aster positioning. Here, we investigate this fundamental question during the migration of asters and pronuclei in C. elegans zygotes, a process essential for the mixing of parental genomes. Detailed quantification of these movements using the female pronucleus as an in vivo probe establish that the drag coefficient of the male-asters complex is approximately five times that of the female pronucleus. Further analysis of embryos lacking cortical dynein, the connection between asters and male pronucleus, or the male pronucleus altogether, uncovers the balance of dynein-driven forces that accurately position microtubule asters in C. elegans zygotes.

Microtubule asters are positioned precisely within cells by forces generated by molecular motors, but it is unclear how these are integrated in space and time. Here the authors perform in vivo drag measurements and genetic manipulations to determine the balance of forces that position microtubule asters in C. elegans zygotes.

Damage-regulated autophagy modulator 1 in oral inflammation and infection

OBJECTIVES

Damage-regulated autophagy modulator (DRAM) 1 is a p53 target gene with possible involvement in oral inflammation and infection. This study sought to examine the presence and regulation of DRAM1 in periodontal diseases.

MATERIAL AND METHODS

In vitro, human periodontal ligament fibroblasts were exposed to interleukin (IL)-1β and Fusobacterium nucleatum for up to 2 days. The DRAM1 synthesis and its regulation were analyzed by real-time PCR, immunocytochemistry, and ELISA. Expressions of other autophagy-associated genes were also studied by real-time PCR. In vivo, synthesis of DRAM1 in gingival biopsies from rats and patients with and without periodontal disease was examined by real-time PCR and immunohistochemistry. For statistics, ANOVA and post-hoc tests were applied (p < 0.05).

RESULTS

In vitro, DRAM1 was significantly upregulated by IL-1β and F. nucleatum over 2 days and a wide range of concentrations. Additionally, increased DRAM1 protein levels in response to both stimulants were observed. Autophagy-associated genes ATG3, BAK1, HDAC6, and IRGM were also upregulated under inflammatory or infectious conditions. In vivo, the DRAM1 gene expression was significantly enhanced in rat gingival biopsies with induced periodontitis as compared to control. Significantly increased DRAM1 levels were also detected in human gingival biopsies from sites of periodontitis as compared to healthy sites.

CONCLUSION

Our data provide novel evidence that DRAM1 is increased under inflammatory and infectious conditions in periodontal cells and tissues, suggesting a pivotal role of DRAM1 in oral inflammation and infection.

CLINICAL RELEVANCE

DRAM1 might be a promising target in future diagnostic and treatment strategies for periodontitis.

Ameloblastin expression and putative autoregulation in mesenchymal cells suggest a role in early bone formation and repair

Ameloblastin is mainly known as a dental enamel protein, synthesized and secreted into developing enamel matrix by the enamel-forming ameloblasts. The function of ameloblastin in tooth development remains unclear, but it has been suggested to be involved in processes varying from regulating crystal growth to activity as a growth factor or partaking in cell signaling. Recent studies suggest that some enamel matrix proteins also might have important functions outside enamel formation. In this context ameloblastin has recently been reported to induce dentin and bone repair, as well as being present in the early bone and cartilage extracellular matrices during embryogenesis. However, what cells express ameloblastin in these tissues still remains unclear. Thus, the expression of ameloblastin was examined in cultured primary mesenchymal cells and in vivo during healing of bone defects in a "proof of concept" animal study. Real time RT-PCR analysis revealed human ameloblastin (AMBN) mRNA expression in human mesenchymal stem cells and primary osteoblasts and chondrocytes. Expression of AMBN mRNA was also confirmed in human CD34 positive cells and osteoclasts. Western and dot blot analysis of cell lysates and medium confirmed the expression and secretion of ameloblastin from mesenchymal stem cells, primary human osteoblasts and chondrocytes. Expression of ameloblastin was also detected in newly formed bone in experimental bone defects in adult rats. Together these findings suggest a role for this protein in early bone formation and repair.

Ameloblastin promotes bone growth by enhancing proliferation of progenitor cells and by stimulating immunoregulators

In this study, we examined the role of the enamel matrix protein, ameloblastin, in bone growth and remodelling, and attempted to identify some of the molecular mechanisms involved in these processes. The effects of recombinant ameloblastin (rAmbn) were tested in vivo in rats, and in vitro in primary human mesenchymal stem cells, osteoblasts, chondrocytes, and osteoclasts. We used a microarray technique to identify genes that were regulated in human osteoblasts and verified our findings using multiplex protein analysis and real-time RT-PCR. Recombinant ameloblastin was found to stimulate bone healing in vivo, and to enhance the proliferation of mesenchymal stem cells and osteoblasts, as well as the differentiation of osteoclast precursor cells in vitro. The most profound effect was on the regulation of genes related to immune responses as well as on the expression of cytokines and markers of bone cell differentiation, indicating that ameloblastin has an effect on mesenchymal cell differentiation. A receptor has not yet been identified, but we found rAmbn to induce, directly and indirectly, signal transducer and activator of transcription (STAT) 1 and 2 and downstream factors in the interferon pathway.

Bioinformatic analysis and molecular modelling of human ameloblastin suggest a two-domain intrinsically unstructured calcium-binding protein

Ameloblastin (AMBN) was originally believed to be an enamel-specific extracellular matrix glycoprotein secreted by ameloblasts. Recently, AMBN expression was also detected in developing mesenchymal dental hard tissues, in trauma-induced reparative dentin, and during early craniofacial bone formation. The function and structure of AMBN still remain ambiguous, and there are no known proteins with similar primary sequences. We therefore performed a bio-informatic analysis of AMBN to model ab initio the three-dimensional structure of the molecule. The results suggest that AMBN is a two-domain, intrinsically unstructured protein (IUP). The analysis did not reveal any regions with structural similarity to known receptor-ligand systems, and did not identify any higher-order structures similar to functional regions in other known sequences. The AMBN model predicts 11 defined regions exposed on the surface, internalizing the rest of the molecule including a human-specific insert. Molecular dynamics analysis identified one specific and several non-specific calcium-binding regions, mostly at the C-terminal part of the molecule. The model is supported by previous observations that AMBN is a bipolar calcium-binding molecule and hints at a possible role in protein-protein interactions. The model provides information useful for further studies on the function of AMBN.

Alveolar macrophages from allergic lungs are not committed to a pro-allergic response and can reduce airway hyperresponsiveness following ex vivo culture

BACKGROUND

We already demonstrated that adoptive transfer of alveolar macrophages (AMs) from non-allergic rats into AM-depleted allergic rats prevents airway hyperresponsiveness (AHR). We also showed that AMs from non-sensitized, but not from sensitized, allergy-prone rats can prevent AHR following allergen challenge in sensitized allergic animals, establishing the importance of rat immunological status on the modulation of AM functions and suggesting that an allergic lung environment alters AM functions.

OBJECTIVE

We investigated how the activation of allergic AMs can be modulated to reinstitute them with their capacity to reduce AHR.

METHODS

AMs from sensitized Brown Norway rats were cultured ex vivo for up to 18 h in culture media to deprogram them from the influence of the allergic lung before being reintroduced into the lung of AM-depleted sensitized recipient. AHR and cytokines in bronchoalveolar lavage (BAL) were measured following allergen challenge. AMs stimulated ex vivo with Bacillus Calmette-Guerin (BCG) were used as positive controls as BCG induces a T-helper type 1 activation in AMs.

RESULTS

AMs ex vivo cultured for 4-18 h reduced AHR to normal level. Interestingly, pro-allergic functions of AMs were dampened by 18 h culture and they reduced AHR even after spending 48 h in an allergic lung microenvironment. Furthermore, transfer of cultured AMs caused an increase in the levels of IFN-gamma and IL-12 in BAL when compared with their ovalbumin control. After 18 h of ex vivo culture, AMs expressed reduced levels of TNF, IL-1alpha, IL-6, and Arginase-2 mRNAs compared with freshly isolated AMs, suggesting that ex vivo culture exempted AMs from lung stimuli that affected their functions.

CONCLUSIONS

There is a significant crosstalk between lung microenvironment and AMs, affecting their functions. It is also the first report showing that sensitized AMs can be modulated ex vivo to reduce lung pro-allergic environment, opening the way to therapies targetting AMs.

Ameloblastin expression during craniofacial bone formation in rats

Based on previous results showing the expression of ameloblastin (Ambn; amelin) in the formation of mesenchymal dental hard tissues, we investigated its presence during bone development. Immunohistochemistry (IHC), in situ hybridization (ISH), and reverse transcription-polymerase chain reaction (RT-PCR) were used to investigate the expression of ameloblastin protein and mRNA during craniofacial development in rats. Tissue samples were collected on embryonic day 18 and from days 2-28 postnatally. IHC revealed the expression of ameloblastin during bone formation at embryonic and early postnatal stages with different patterns of expression in intramembranous and endochondral ossification. In intramembranous ossification, ameloblastin expression was detected in the superficial layer of the condensed vascularized primitive connective tissue and in the cellular layer covering the surface of the newly formed woven bone. In endochondral ossification, ameloblastin was expressed within the extracellular matrix of the cartilage templates and in the perichondrium. Between days 2 and 28 the expression decreased markedly, concordant with the maturation of the bone, and disappeared after completion of bone remodeling. The results obtained by IHC were confirmed by ISH and RT-PCR, showing the expression of ameloblastin mRNA during craniofacial bone formation. This study indicates the expression of the putative dental protein ameloblastin during craniofacial bone development in rats.

Ameloblastin fusion protein enhances pulpal healing and dentin formation in porcine teeth

Ameloblastin (Ambn, also named "amelin" or "sheathlin") is a protein participating in enamel formation and mesenchymal-ectodermal interaction during early dentin formation in developing teeth. Experiments have demonstrated an association between Ambn expression and healing of acute pulp wounds. The purpose of this study was to investigate if local application of recombinant fusion Ambn (rAmbn) could influence reparative dentin formation in pulpotomized teeth. In this randomized, double-blinded study, pulpotomy was performed in 28 lower central incisors in 17 adult miniature pigs. Following the surgical procedure, the exposed pulp tissue was covered either with rAmbn or with calcium hydroxide. After 2, 4, or 8 weeks, the teeth were extracted and examined by histomorphometry and immunohistochemistry using antibodies against porcine ameloblastin, collagen type I, and dentin sialoprotein (DSP). In rAmbn-treated teeth, a substantial amount of newly formed reparative dentin was observed at the application site, completely bridging the pulpal wound. Dentin formation was also observed in calcium hydroxide-treated teeth; however, the amount of reparative dentin was significantly smaller (P < 0.001) than after rAmbn treatment. Immunohistochemistry confirmed that the new hard tissue formed was similar to dentin. This is the first time a direct link between ameloblastin and dentin formation has been made in vivo. The results suggest potential for rAmbn as a biologically active pulp-dressing agent for enhanced pulpal wound healing and reparative dentin formation after pulpotomy procedures.

Periodontal infections and coronary heart disease: role of periodontal bacteria and importance of total pathogen burden in the Coronary Event and Periodontal Disease (CORODONT) study

BACKGROUND

Chronic inflammation from any source is associated with increased cardiovascular risk. Periodontitis is a possible trigger of chronic inflammation. We investigated the possible association between periodontitis and coronary heart disease (CHD), focusing on microbiological aspects.

METHODS

A total of 789 subjects (263 patients with angiographically confirmed, stable CHD and 526 population-based, age- and sex-matched controls without a history of CHD) were included in the Coronary Event and Periodontal Disease (CORODONT) study. Subgingival biofilm samples were analyzed for periodontal pathogens Actinobacillus actinomycetemcomitans, Tannerella forsythensis, Porphyromonas gingivalis, Prevotella intermedia, and Treponema denticola using DNA-DNA hybridization. The need for periodontal treatment in each subject was assessed using the Community Periodontal Index of Treatment Needs (CPITN). The main outcome measures included total periodontal pathogen burden, number of the various periodontal pathogens in the subgingival biofilm, and periodontal treatment needs (according to the CPITN).

RESULTS

In multivariable analyses, we found a statistically significant association between the periodontal pathogen burden (log10 of the sum of all pathogens) (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.34-2.74; P<.001) or the number of A actinomycetemcomitans in periodontal pockets (log10) (OR, 2.70; 95% CI, 1.79-4.07; P<.001) and the presence of CHD. In addition, a statistically significant association between an increase in mean CPITN score by 1 and the presence of CHD (OR, 1.67; 95% CI, 1.08-2.58; P = .02) was observed.

CONCLUSIONS

Our findings suggest an association between periodontitis and presence of CHD. Periodontal pathogen burden, and particularly infection with A actinomycetemcomitans, may be of special importance.

Coverage of Miller Class I and II Recession Defects Using Enamel Matrix Proteins Versus Coronally Advanced Flap Technique: A 2-Year Report

BACKGROUND

The aim of this study was to evaluate a comparison of the coronally advanced flap procedure with or without the use of enamel matrix proteins in the treatment of recession defects.

METHODS

This 2-year study was conducted as a blinded, split-mouth, placebo-controlled, and randomized design. Thirty patients from two dental schools with two paired buccal recession defects were chosen. Surgical recession coverage was performed as the coronally advanced flap technique. One site was additionally treated with derivative (EMD) and the other site with a placebo (propylene glycol alginate [PGA]). A blinded examiner assessed pre- and post-surgical measurements. Measurements comprised the height and width of the gingival recession, height of keratinized tissue, probing attachment level, probing depth, and alveolar bone level.

RESULTS

Twenty-four months after therapy, both treatment modalities showed significant root coverage and probing attachment gain. The mean gingival recession decreased from 3.6 to 0.8 mm for the EMD-treated sites and from 3.8 to 1.4 mm for the control sites. However, this difference was not statistically significant (P = 0.122). Similarly, all other clinical parameters did not differ significantly in the between-group comparison except for the recession width (P = 0.027) and probing depth (P = 0.046) exhibiting higher reductions in the EMD group. Complete root coverage could be maintained over 2 years in 53% of the EMD versus merely 23% in the control group. A total of 47% of the treated recessions in the control group deteriorated again in the second year after therapy compared to 22% in the EMD group.

CONCLUSION

Enamel matrix derivative seems to provide better long-term results.

Adiponectin and its receptors are expressed in bone-forming cells

Adiponectin has until now been considered to be synthesized and secreted exclusively by the adipose tissue, and is reported to influence energy homeostasis and insulin sensitivity. It is also known that body weight is positively correlated with increased bone mineral density and decreased fracture risk. The mechanisms explaining this relation, however, are not completely understood. We report a link between adiponectin and bone homeostasis by demonstrating transcription, translation, and secretion of adiponectin, as well as expression of its receptors, AdipoR1 and AdipoR2, in bone-forming cells. We show that adiponectin and the receptors are expressed in primary human osteoblasts from femur and tibia. The phenotype of bone cells was confirmed by the high expression levels of alkaline phosphatase, collagen type 1, osteocalcin, and CD44, and the formation of mineralization nodules. Immunostaining with monoclonal antibodies also demonstrated the presence of adiponectin in human osteosarcoma cells and normal osteoblasts. Both mRNA expression and secretion of adiponectin to the medium increased during differentiation of human osteoblasts in culture. The adiponectin mRNA level increases in osteoblasts cultured 3 and 7 days in the presence of dietary fatty acids and supplementation of culture medium with recombinant adiponectin enhances the proliferation of murine osteoblasts. The regulation and detailed function of adiponectin in bone still remains obscure, but our findings suggest a functional role in bone homeostasis. If so, adiponectin may provide an important signal linking fat and body weight to bone density.

Additive antimicrobial activity of calcium hydroxide and chlorhexidine on common endodontic bacterial pathogens

It is an established procedure to use calcium hydroxide [Ca(OH)2] as a therapeutic component to achieve sterilization of infected root canals. Unfortunately, some bacterial species are relatively resistant to Ca(OH)2 and are therefore associated with treatment failures. The objective of this study was to identify combinations of substances that improve antimicrobial activity. Ca(OH)2 was used as a suspension or as a component of gutta-percha points. Efficacy of killing was compared for (a) Ca(OH)2 suspension alone; (b) zinc oxide (ZnO) points alone; (c) Ca(OH)2 suspension combined with ZnO points; (d) Ca(OH)2 suspension combined with ZnO/chlorhexidine points; and (e) Ca(OH)2 points combined with ZnO/chlorhexidine points. Common endodontopathogenic bacterial species (Enterococcus faecalis, Fusobacterium nucleatum, Peptostreptococcus micros, Porphyromonas gingivalis, Streptococcus intermedius) in pure cultures served as target organisms. In the in vitro assay, the antibacterial substances and approximately 10(7) colony forming units of test bacteria were co-incubated in diluted human serum under growth conditions appropriate for the single bacterial species. Samples were taken on days 0, 1, 2, 4, 7, and 14 of incubation and viable counts determined. Gram-negative bacteria were sufficiently killed by Ca(OH)2 alone. Combinations with other agents did not improve the killing kinetics. For the inactivation of the Gram-positive bacteria P. micros and S. intermedius, a combination of Ca(OH)2 and ZnO/chlorhexidine, killed the bacteria faster than Ca(OH)2 alone. For E. faecalis, combining Ca(OH)2 suspension with ZnO/chlorhexidine points lead to a faster decrease in the overall number of viable bacteria, but no test conditions lead to the complete loss of culture viability. The results of this study support the use of a combination of Ca(OH)2 and chlorhexidine for faster eradication of P. micros and S. intermedius from infected root canals.

Expression of amelin and trauma-induced dentin formation

According to recent studies, amelin (ameloblastin, sheathlin) is expressed in young odontoblasts at the initiation of dentin formation during odontogenesis. The purpose of the present investigation was to study whether amelin is also expressed at the onset of trauma-induced reparative dentin formation. The mandibular developing first molars of 5-day-old rats were surgically taken out, and their pulp tissue briefly separated from the inner dentin surface and immediately repositioned. Then the teeth were re-implanted in their alveoli. At 0, 2, 4, 6, 8, 12 or 14 days after surgery, the animals were sacrificed and the experimental teeth evaluated by histology and immunohistochemistry for amelin. At 2, 4, 6 and 8 days after surgery, the detached and traumatized odontoblasts in the experimental teeth exhibited increasing signs of degeneration and loss of intracellular structures. At days 6 and 8 after surgery, immunohistochemistry revealed a strong staining for amelin in the traumatized odontoblastic layer. Twelve and 14 days after replantation, only necrotic cell remnants of the traumatized odontoblasts were discernible. At this stage, no amelin could be detected by immunostaining. A wide zone of an unorganized mineralized tissue surrounded the odontoblastic cell remnants. On the pulpal side of the unorganized tissue, a new, highly organized tubular reparative dentin layer was observed, bordered by columnar odontoblast-like cells abutting on newly formed predentin. The results indicate that the initiation of trauma-induced reparative dentin formation mimics that of primary dentin formation and that amelin seems to be involved in both processes, possibly as a signaling molecule.

Comparative study of Emdogain and coronally advanced flap technique in the treatment of human gingival recessions. A prospective controlled clinical study

OBJECTIVES

Various surgical techniques have been proposed for coverage of denuded root surfaces. The aim of this study was to evaluate a comparison of coronally repositioned flap procedure with or without the use of enamel matrix proteins in the treatment of recession defects.

MATERIAL AND METHODS

This study was an intra-individual longitudinal test of 12 months duration conducted as a blinded, split-mouth, placebo-controlled and randomised design. It was performed in 2 dental schools. 36 patients, aged 22-62 years, with 2 paired buccal recession defects of at least 3 mm participated. Surgical recession coverage was performed as coronally-advanced flap technique at both sites in the same session. One site was additionally treated with commercially-available enamel matrix proteins (Emdogain) and the other site with placebo (propylene glycol alginate) in accordance with the randomisation list. A blinded examiner assessed pre- and post-surgical measurements. Clinical measurements and photographs were taken pre-surgically and after 1 week, 3 weeks, 3 months, 6 months and 12 months, postoperatively. Measurements comprised height and width of the gingival recession, height of keratinized tissue, probing attachment level, probing pocket depth and alveolar bone level by periodontal probe, Florida Probe or caliper to the nearest 0.5 mm.

RESULTS

12 months after therapy, both treatment modalities showed significant root coverage and probing attachment gain. Gingival recession decreased from 3.7 mm to 0.8 mm for the Emdogain treated sites and from 3.9 mm to 1.0 mm for the control sites, corresponding to mean root coverages of 80% and 79%, respectively. This difference was not significant. With the exception of keratinized tissue gain, which was significantly higher (p=0.003) in the Emdogain group, all other clinical variables were not different in the between-group comparison.

CONCLUSIONS

As the additional use of Emdogain together with coronally advanced flap technique for recession coverage showed no difference in the overall clinical outcome, there is no clear benefit to combine Emdogain with this surgical technique.

Effect of the enamel matrix derivative Emdogain on the growth of periodontal pathogens in vitro

OBJECTIVES

The aim of this study was to evaluate the effect of Emdogain (EMD), used for periodontal regeneration, on the growth of periodontal pathogens like Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia. For comparison, we studied the effect of EMD on several microbes associated with other oral diseases as well as its effect on non-pathogenic oral inhabitants.

METHODS

Freshly prepared EMD or its vehicle propylene glycol alginate (PGA) alone were added to calibrated suspensions of microbes. As a control, imitating the post-surgical subgingival situation after flap closure, a serum/NaCl-solution mixture was used. Aliquots for growth assays were taken at scheduled times for calculation of colony-forming units and cell densities over an observation period of 24 h. Additionally, EMD was spotted onto selected, newly seeded microbes growing on agar plates to see if growth inhibition zones could be produced.

RESULTS

The study revealed a marked inhibitory effect of EMD on the growth of the gram-negative periodontal pathogens. A. actinomycetemcomitans showed a significant decrease (p=0.012) in viable counts after 24 h when EMD was added at baseline. P. gingivalis and P. intermedia also showed a marked growth reduction in the presence of EMD and in these cultures no viable microbes could be detected anymore after 24 h. In contrast, no significant growth inhibition was observed in gram-positive bacteria.

CONCLUSIONS

The results suggest that EMD has a positive effect on the composition of bacterial species in the post-surgical periodontal wound, by selectively restricting growth of periopathogens that could hamper the wound healing and reduce the outcome of regenerative procedures.

Helicobacter pylori in the oral cavity: high prevalence and great DNA diversity

To test the hypothesis that Helicobacter pylori may be transmitted by the oral-oral route, we applied nested PCR and DNA sequencing to detect and analyze H. pylori DNA in the oral cavity of 20 adult patients undergoing endoscopy. Dental plaques of molars, premolars, and incisors and saliva were collected. Additional paraffin-embedded gastric biopsies were analyzed in four patients. Two sets of highly sensitive and specific primers, EHC-U/EHC-L and ET5-U/ET-5L directed to a 860-bp fragment of H. pylori DNA, were used in the nested PCR. Eight patients had an active infection in the stomach determined with the [13C]urea breath test and the other 12 were negative. Nested PCR showed that all 20 subjects (100%) were positive for H. pylori in the oral cavity. DNA sequencing demonstrated that all tested PCR products of the expected size from the oral samples have more than 97% identity with that from H. pylori type strain ATCC 43629. However, sequences differed in oral samples from different subjects as well as between different oral locations and gastric biopsies within the same individuals. In conclusion, the oral cavity may be a permanent reservoir for H. pylori and can harbor multiple H. pylori strains at the same time.

Effect of gingival fluid on marginal adaptation of Class II resin-based composite restorations

PURPOSE

To evaluate in vitro the marginal quality of Class II composite restorations at the gingival enamel margins as affected by contamination of the cavities with gingival fluid (GF) during different steps of resin bonding procedures.

MATERIALS AND METHODS

70 Class II cavities were prepared in extracted human molars and restored with composite using a multi-component bonding system (OptiBond FL/Herculite XRV; OPTI) or a single-bottle adhesive (Syntac Sprint/Tetric Ceram; SYN). The cavities were contaminated with human GF: C1 after acid etching, C2 after application of the primer (OPTI) or light-curing of the primer-adhesive (SYN), and C3 after light-curing of the resin adhesive (OPTI). Uncontaminated cavities were used as the control (C0). The restored teeth were subjected to thermocycling (TC) and replicated for SEM analysis of marginal gap formation. Microleakage at the gingival margins was determined by dye penetration with basic fuchsin.

STATISTICS

non-parametric tests (Kruskal-Wallis test, Mann-Whitney test with Bonferroni correction).

RESULTS

In both bonding systems, contamination with GF after acid etching (C1) did not impair the marginal quality; the mean percentages of continuous margin/mean depths of dye penetration were: OPTI: C0: 88.5%/0.10 mm, C1: 95.6%/0.04 mm; SYN: C0: 90.9%/0.08 mm, C1: 97.0%/0.05 mm. Marginal adaptation was adversely affected when GF contamination was performed after

Characteristic distribution pattern of Helicobacter pylori in dental plaque and saliva detected with nested PCR

The precise mode of transmission and the natural reservoir for Helicobacter pylori are unknown. PCR assays have proved to be highly sensitive and specific and are regarded as the method of choice for detecting H. pylori DNA in the oral cavity. The aim of this study was to investigate the prevalence and distribution of H. pylori in the oral cavity. Forty-two patients undergoing gastroscopy were investigated for the presence of H. pylori in dental plaque and saliva by nested PCR, and in the stomach by the 13C-urea breath test. Samples tested comprised dental plaque from molars, premolars and incisors and saliva. Two sets of primers homologous to the 860-bp fragment of H. pylori DNA, which have been shown previously to be highly sensitive and specific, were used for nested PCR. Eleven patients (26.2%) were infected with H. pylori in the stomach. H. pylori DNA was identified in dental plaque samples from 41 patients (97%) and in 23 saliva samples (55%). The prevalence in dental plaque from molars, premolars and incisors was 82%, 64% and 59%, with an odds ratio of 3.18, 1.24 and 1 (reference), respectively. In conclusion, H. pylori was present in the oral cavity of 97% of tested patients, with a characteristic distribution that was independent of the infection status of the stomach. Thus H. pylori may belong to the normal oral microflora.

Response of dental follicular cells to the exposure of denuded enamel matrix in rat molars

Recent studies have indicated that cementum formation can be induced when dental follicular cells are exposed to enamel matrix. The purpose of the present investigation was to study this cementum formation and the appearance of the cells involved, including their expression of collagen types alpha1(I), alpha1(II) and alpha1(III) mRNAs, during this process by means of light microscopy and in situ hybridisation. The mandibular first molars of 5-d-old rats were surgically taken out, their enamel epithelium was removed, and then the crowns were re-inserted with the occlusal surface downwards in their crypts to allow the follicular cells to come in contact with the denuded enamel matrix. After observation periods of 2-14 d, the teeth were prepared for light microscopic examination and in situ hybridisation. A monolayer of follicular cells in contact with the exposed enamel matrix changed their morphology and increased their expression of collagen type I mRNA as early as 2-4 d after exposure to the enamel matrix. A cementum-like tissue was formed at the surface of the enamel matrix. Collagen type II mRNA was never expressed in the tissues studied, whereas collagen type III mRNA was weakly expressed in the follicular cells throughout the experiment.

Chondrodysplasia punctata with a mild clinical course

We report a 7-year-old patient with chondrodysplasia punctata but without rhizomelia. He was born with typical clinical and radiological symptoms of this disease. He developed slowly with considerable psychomotor retardation but improved later, gaining some speech and psychosocial contacts. Joint contractures and bilateral cataracts are still major problems. De novo plasmalogen synthesis in fibroblasts was greatly reduced and DHAP-AT activity was at the lower limit of controls. Peroxisomal thiolase was present in its precursor form only. Membrane fluidity (measured by TMA-DPH fluorescence anisotropy) was increased in erythrocyte ghosts and in lymphocytes. Plasma phytanic acid concentration was elevated 5-fold. The patient represents a mild clinical course of chondrodysplasia punctata, resembling Conradi-Hünermann syndrome, but biochemically he has the typical peroxisomal dysfunction of rhizomelic chondrodysplasia punctata except for a high residual activity of DHAP-AT.

[Familial distribution of cholesterolemia, arterial blood pressure and relative weight]

The "Sion" study, a part of the Swiss National Research Program on Cardiovascular diseases, investigated the relationships between parents' and children's cholesterolemia, blood pressure and relative weight. After a health control at school 101 fathers and 108 mothers of ten year old children have been examined. The representativeness of these parents was studied using twice as many adults of the same age from Nyon and from Aarau. Direct significant statistical associations are then demonstrated between fathers' and children's blood pressure, cholesterolemia and relative weight. Analogous associations were found out for the last two variables only between mothers and children. Available data suggest that environmental determinants of risk factor exposure are more likely to explain these relationships. It then appears that the family represents a proper setting for primary prevention.

Tyrosinemia without liver or renal damage with plantar and palmar keratosis and keratitis (hypertyrosinemia type II)

A boy of 3 2/12 years of age with Richner-Hanhart syndrome (plantar and palmar keratosis and chronic keratitis) was found to have hypertyrosinemia and to excrete the hydroxyacids derived from tyrosine. A diet poor in phenylalanine and tyrosine cured the skin and corneal lesions. Clinical and biochemical observations are reported.

Prepubertal XX male with profound physical and mental deficiency, retinitis pigmentosa and multiple congenital anomalies

A unique case of a prepubertal XX male with profound mental and physical retardation, retinitis pigmentosa, ambiguous genitalia and multiple congenital anomalies is reported. His clinical, genetic, dermatoglyphic and histological findings are presented. This case could represent a new multiple congenital malformation syndrome. Theories on XX male aetiology are briefly discussed.

[Hereditary hypogranular thrombocytopathic thrombocytopenia. Ultrastructural study of a megakaryocytopathy (author's transl)]

The ultrastructure of megakaryocytes and blood platelets has been studied in 3 members of a Swiss family, in which a haemorrhagic diathesis of varying degree occurred in at least three generations. Blood platelets show an extremely low number of dense granules, slightly increased mean diameter and irregular distribution of glycogen in unusually large clusters. The number of megakaryocytes in bone marrow is normal. Electron microscopy shows asynchronous development of their structural components: a severe defect in maturation of specific granules is followed by retardation and irregularity in the demarcation of the "platelet prospective fields", Golgi membranes have few vesicles, glycogen occurs partly in huge clusters and megakaryocytes with mature platelet fields are very rare. The ultrastructural picture of platelet formation in megakaryocytes indicates that this haemorrhagic syndrome may be understood as a megakaryocytopathy. The results of functional and biochemical analyses performed on blood platelets show a defect in both phases of aggregation and in PF 3 availability, normal survival, decreased total sialic acid content, and absence of the heaviest platelet population ("D") isolated by discontinuous sucrose gradient. The autosomal dominant transmission of this together with its concomitance with blood group O suggest its relationship with the familial thrombopathic thrombocytopenia described in 1968 by Kurstjens and al. in a Dutch family [13].