Restorative dentistry and restorative materials over the next 20 years: A Delphi survey

OBJECTIVES The aim of this study was to forecast trends in restorative dentistry over the next 20 years and to identify treatment goals and corresponding properties of restorative materials. METHODS Using the Delphi method, a panel of 3 experts identified 8 key questions, which were sent to experts in restorative and preventive dentistry. In round 1 of this survey, 15 international experts devised a clearer semantic definition of the key questions and the completion of respective items for two additional rounds. In round 2, 125 experts from 35 countries rated the items developed in round 1 using a Likert scale. In round 3, the same 125 experts received the ratings of round 2 and were asked to agree or disagree to these ratings by re-voting on all key questions and items. A total of 105 experts re-voted and finally took part in the complete survey. Among the 8 key questions, two questions were selected for the present report: (Q1) "What will be the future role of restorative treatment?" and (Q6) "What will be the key qualities for clinical success of restorations?" For both questions and the respective items, the experts were asked to evaluate the importance and the feasibility for later calculation of the scientific value (i.e. the opportunity, where opportunity=importance+[importance-feasibility]). RESULTS The three items of highest importance for Q1 were "preservation of existing enamel and dentin tissue," "prevention of secondary caries," and "maintenance of the pulp vitality," and for Q6 they were "optimization of adhesion," "biocompatibility," and "minimizing technical sensitivity." SIGNIFICANCE Bioactivity toward the pulp-dentin complex and prevention of secondary caries were the items generally rated as having the highest opportunity.

Effects of Prolyl Hydroxylase Inhibitor L-mimosine on Dental Pulp in the Presence of Advanced Glycation End Products

INTRODUCTION Proangiogenic prolyl hydroxylase (PHD) inhibitors represent a novel approach to stimulate tissue regeneration. Diabetes mellitus involves the accumulation of advanced glycation end products (AGEs). Here we evaluated the impact of AGEs on the response of human pulp tissue to the PHD inhibitor L-mimosine (L-MIM) in monolayer cultures of dental pulp-derived cells (DPCs) and tooth slice organ cultures. METHODS In monolayer cultures, DPCs were incubated with L-MIM and AGEs. Viability was assessed based on formazan formation, live-dead staining, annexin V/propidium iodide, and trypan blue exclusion assay. Vascular endothelial growth factor (VEGF), interleukin (IL)-6, and IL-8 production was evaluated by quantitative polymerase chain reaction and immunoassays. Furthermore, expression levels of odontoblast markers were assessed, and alizarin red staining was performed. Tooth slice organ cultures were performed, and VEGF, IL-6, and IL8 levels in their supernatants were measured by immunoassays. Pulp tissue vitality and morphology were assessed by MTT assay and histology. RESULTS In monolayer cultures of DPCs, L-MIM at nontoxic concentrations increased the production of VEGF and IL-8 in the presence of AGEs. Stimulation with L-MIM decreased alkaline phosphatase levels and matrix mineralization also in the presence of AGEs, whereas no significant changes in dentin matrix protein 1 and dentin sialophosphoprotein expression were observed. In tooth slice organ cultures, L-MIM increased VEGF but not IL-6 and IL-8 production in the presence of AGEs. The pulp tissue was vital, and no signs of apoptosis or necrosis were observed. CONCLUSIONS Overall, in the presence of AGEs, L-MIM increases the proangiogenic capacity, but decreases alkaline phosphatase expression and matrix mineralization.

Prolyl hydroxylase inhibitors increase the production of vascular endothelial growth factor in dental pulp-derived cells

Introduction: Prolyl hydroxylase (PHD) inhibitors can induce a proangiogenic response that stimulates regeneration in soft and hard tissues. However, the effect of PHD inhibitors on the dental pulp is unclear. The purpose of this study was to evaluate the effects of PHD inhibitors on the proangiogenic capacity of human dental pulp–derived cells. Methods: To test the response of dental pulp–derived cells to PHD inhibitors, the cells were exposed to dimethyloxalylglycine, desferrioxamine, L-mimosine, and cobalt chloride. To assess the response of dental pulp cells to a capping material supplemented with PHD inhibitors, the cells were treated with supernatants from calcium hydroxide. Viability, proliferation, and protein synthesis were assessed by formazan formation, 3[H]thymidine, and 3[H]leucine incorporation assays. The effect on the proangiogenic capacity was measured by immunoassays for vascular endothelial growth factor (VEGF). Results: We found that all 4 PHD inhibitors can reduce viability, proliferation, and protein synthesis at high concentrations. At nontoxic concentrations and in the presence of supernatants from calcium hydroxide, PHD inhibitors stimulated the production of VEGF in dental pulp–derived cells. When calcium hydroxide was supplemented with the PHD inhibitors, the supernatants from these preparations did not significantly elevate VEGF levels. Conclusions: These results show that PHD inhibitors can stimulate VEGF production of dental pulp–derived cells, suggesting a corresponding increase in their proangiogenic capacity. Further studies will be required to understand the impact that this might have on pulp regeneration.

Laser Doppler flowmetry for assessment of anterior mandibular teeth in conjunction with bone harvesting in the symphysis: a clinical pilot study

PURPOSE: To evaluate the pulp sensitivity and vitality of mandibular incisors and canines before and after bone harvesting in the symphysis. MATERIALS AND METHODS: In 20 patients requiring bone grafts from the symphysis, pulp sensitivity (carbon dioxide [CO2]) and pulpal blood flow (laser Doppler flowmetry [LDF]) of mandibular incisors and canines were evaluated preoperatively, postoperatively, and 6 months after surgery. Teeth were allocated to 1 of 3 groups according to their initial and final reaction to CO2 (group A = teeth with a positive reaction throughout the study, group B = teeth that exhibited a sensitivity change from positive to negative, and group C = teeth with a negative reaction throughout the study). RESULTS: Preoperative flux measurements (LDF) did not differ between groups A, B, and C. Teeth with sensitivity changes (group B) showed the greatest decrease (a statistically significant decrease) of pulpal blood flow over time, whereas teeth in groups A and C demonstrated an insignificant reduction of flux over time. DISCUSSION AND CONCLUSIONS: LDF was purely used as an experimental tool in the present study. Pulpal blood flow measurements using LDF demonstrated a decrease of flux over time in anterior mandibular teeth following bone harvesting in the symphysis. A significant change of flux, however, was only observed for teeth that also demonstrated a loss of pulp sensitivity during the same study period. Loss of pulp sensitivity appeared to be correlated to a significant decrease of blood flow assessed by LDF.

Immunodetection of bone-related proteins in microcalcifications of human dental pulp

Objective: Root canal obliterations may pose esthetic and clinical problems or may even be a risk factor for tooth survival. Microcalcifications in the pulp can be so extensive that the entire root canal system becomes obliterated. Since bone sialoprotein (BSP) and osteopontin (OPN) are involved in both physiological and pathological mineralization processes, our hypothesis was that these two bone-related noncollagenous proteins are present in microcalcifications of the pulp. The purpose of this study was, therefore, to characterize the nature of microcalcifications in the pulp of aged human teeth. Methods: From a large collection of human teeth, 10 were found to exhibit pulpal microcalcifications. The teeth were extracted for periodontal reasons from 39-60 year old patients. After fixation in aldehydes and decalcification, teeth were processed for embedding in LR White resin for analysis in the light and transmission electron microscope. For the detection of BSP and OPN, post-embedding high resolution immunocytochemistry was applied. Results: The microcalcifications were round or elongated, occasionally coalescing, and intensely stained with toluidine blue. Collagen fibrils were found in most but not all microcalcifications. All microcalcifications were immunoreactive for both antibodies and showed an identical labeling pattern. Gold particle labeling was extensively found throughout the interfibrillar ground substance of the microcalcifications, whereas the dentin matrix lacked immunolabeling. Conclusion: BSP and OPN appear to be major matrix constituents of pulp microcalcifications and may thus, like in other mineralized tissues, be involved in their mineralization process.

Loss of pulp sensitivity and pain as the first symptoms of a Ewing's sarcoma in the right maxillary sinus and alveolar process: report of a case

This case report describes the diagnosis and treatment of a Ewing's sarcoma in the right maxillary sinus and alveolar bone of a 19-year-old female patient. The first clinical symptoms were a loss of sensitivity of the premolars and first molar in the right maxilla and acute pain located in the area of these teeth. Initially, the referring dentist had treated these findings as an acute apical periodontitis with root canal medication. Because swellings on the palatal and buccal aspects of the teeth occurred and could not be treated with incision and drainage, the dentist referred the patient. Cone-beam computed tomography revealed a proliferation of soft tissue in the right maxillary sinus, with a radiopaque material at the tip of the mesiobuccal root of the first molar and resorptive signs of the mesiobuccal and distobuccal roots of the first molar. The palatal cortical bone of the right alveolar process seemed to be intact. After explorative surgery with biopsies from the buccal, palatal, and sinus proliferation areas, the pathologist diagnosed the lesion as a Ewing's sarcoma. Treatment of the patient consisted of initial chemotherapy, hemimaxillectomy, and postsurgical chemoradiotherapy.

Pulp and periodontal healing of laterally luxated permanent teeth: results after 4 years

AIM: To evaluate the pulp and periodontal healing of laterally luxated permanent teeth. MATERIAL AND METHODS: Patients presenting with lateral luxation of permanent teeth during 2001-2002 were enrolled in this clinical study. Laterally luxated teeth were repositioned and splinted with a TTS/composite resin splint for 4 weeks. Immediate (prophylactic) root-canal treatment was performed in severely luxated teeth with radiographically closed apices. All patients received tetracycline for 10 days. Re-examinations were performed after 1, 2, 3, 6, 12 and 48 months. RESULTS: All 47 laterally luxated permanent teeth that could be followed over the entire study period survived. In 10 teeth (21.3%), a prophylactic root-canal treatment was performed within 2 weeks following injury. The remaining 37 teeth showed the following characteristics at the 4-year re-examination: 19 teeth (51.4%) had pulp survival (no clinical or radiographic signs or symptoms), nine teeth (24.3%) presented with pulp canal calcification, and pulp necrosis was seen in another nine teeth (24.3%), within the first year after trauma. None of the teeth with a radiographically open apex at the time of lateral luxation showed complications. External root resorption was only seen in one tooth. CONCLUSIONS: Laterally luxated permanent teeth with incomplete root formation have a good prognosis, with all teeth surviving in this study. The most frequent complication was pulp necrosis that was only seen in teeth with closed apices.

Action of food preservatives on 14-days dental biofilm formation, biofilm vitality and biofilm-derived enamel demineralisation in situ

AIMS The aims of this double-blind, controlled, crossover study were to assess the influence of food preservatives on in situ dental biofilm growth and vitality, and to evaluate their influence on the ability of dental biofilm to demineralize underlying enamel over a period of 14 days. MATERIALS AND METHODS Twenty volunteers wore appliances with six specimens each of bovine enamel to build up intra-oral biofilms. During four test cycles of 14 days, the subjects had to place the appliance in one of the assigned controls or active solutions twice a day for a minute: negative control 0.9 % saline, 0.1 % benzoate (BA), 0.1 % sorbate (SA) and 0.2 % chlorhexidine (CHX positive control). After 14 days, the biofilms on two of the slabs were stained to visualize vital and dead bacteria to assess biofilm thickness (BT) and bacterial vitality (BV). Further, slabs were taken to determine mineral loss (ML), by quantitative light-induced laser fluorescence (QLF) and transversal microradiography (TMR), moreover the lesion depths (LD). RESULTS Nineteen subjects completed all test cycles. Use of SA, BA and CHX resulted in a significantly reduced BV compared to NaCl (p < 0.001). Only CHX exerted a statistically significant retardation in BT as compared to saline. Differences between SA and BA were not significant (p > 0.05) for both parameters. TMR analysis revealed the highest LD values in the NaCl group (43.6 ± 44.2 μm) and the lowest with CHX (11.7 ± 39.4 μm), while SA (22.9 ± 45.2 μm) and BA (21.4 ± 38.5 μm) lay in between. Similarly for ML, the highest mean values of 128.1 ± 207.3 vol% μm were assessed for NaCl, the lowest for CHX (-16.8 ± 284.2 vol% μm), while SA and BA led to values of 83.2 ± 150.9 and 98.4 ± 191.2 vol% μm, respectively. With QLF for both controls, NaCl (-33.8 ± 101.3 mm(2) %) and CHX (-16.9 ± 69.9 mm(2) %), negative values were recorded reflecting a diminution of fluorescence, while positive values were found with SA (33.9 ± 158.2 mm(2) %) and BA (24.8 ± 118.0 mm(2) %) depicting a fluorescence gain. These differences were non-significant (p > 0.05). CONCLUSION The biofilm model permited the assessment of undisturbed oral biofilm formation influenced by antibacterial components under clinical conditions for a period of 14 days. An effect of BA and SA on the demineralization of enamel could be demonstrated by TMR and QLF, but these new findings have to be seen as a trend. As part of our daily diet, these preservatives exert an impact on the metabolism of the dental biofilm, and therefore may even influence demineralization processes of the underlying dental enamel in situ.

Exploring Growth Variability and Crown Vitality of Sessile Oak (Quercus Petraea) in the Czech Republic

Unraveling climatic effects on growth of oak - Europe’s most ecologically and economically important forest species - has been the subject of many recent studies; however, more insight based on field data is necessary to better understand the relationship between climate and tree growth and to adapt forest management strategies to future climate change. In this report, we explore the influence of temperature, precipitation and drought variability on the productivity and vitality of oak stands in the Czech Highlands. We collected 180 cores from mature oaks (Quercus petraea) at four forest stands in the Czech Drahany Highlands. Standard dendromethods were used for sample preparation, ring width measurements, cross-dating, chronology development, and the assessment of growth-climate response patterns. Crown vitality was also evaluated, using the modified ICP Forests methodology. Late spring precipitation totals between May and June as well as the mean July temperature for the year of ring formation were found to be the most important factors for oak growth, whereas crown condition was significantly affected by spring and summer drought. This study is rep-resentative for similar bio-ecological habitats across Central Europe and can serve as a dendroclima-tological blueprint for earlier periods for which detailed meteorological information is missing .

Differential inflammatory response of dental pulp explants and fibroblasts to saliva

Abstract AIM: To investigate the inflammatory response of dental pulp fibroblasts and the respective explants to whole saliva. METHODOLOGY: Explants from human and porcine dental pulp tissue and isolated dental pulp fibroblasts were used to investigate the inflammatory response to sterile saliva. Cytokine and chemokine expression was assessed by RT-PCR. Western blot analysis and pharmacologic inhibitors were used to determine the involvement of signalling pathways. RESULTS: Dental pulp explants of human and porcine origin exposed to human saliva exhibited no major changes of IL-6 and IL-8 mRNA expression (P > 0.05). In contrast, isolated porcine and human dental pulp fibroblasts, when stimulated with human saliva, exhibited a vastly increased expression of IL-6 and IL-8 mRNA (P < 0.05). In pulp fibroblasts, saliva also increased the expression of other cytokines and chemokines via activation of NFkappaB, ERK and p38 signalling. Notably, a significantly reduced inflammatory response was elicited when pulp fibroblasts were transiently exposed to saliva. CONCLUSIONS: Saliva has a potential impact on inflammation of dental pulp fibroblasts in vitro but not when cells are embedded in the intrinsic extracellular matrix of the explant tissue.

Religious Diversity and Religious Vitality: New Measuring Strategies and Empirical Evidence

Quantitative studies of the conditions and consequences of religious diversity are based mostly on indices that measure the variety of religious membership in a particular region. However, this line of research has become stagnant, and the question of whether diversity affects religious vitality remains unanswered. This article attempts to shed new light on the discussion by measuring religious diversity differently and capturing religious vitality independently of membership figures. In particular, it contrasts the Herfindahl-Hirschman Index based on membership proportions with a second measure of diversity: an index of organizational diversity. Conversely, the dependent variable religious vitality is measured not by using rates of participation in religious organizations but via the Centrality of Religion Scale. Based on ecological and individual level data of forty-three local regions in Finland, Germany, and Slovenia and using multilevel analysis, our results suggest that religious diversity is related to religious vitality. However, the nature of this association differs across subgroups.