Clinical guidelines for treating caries in adults following a minimal intervention policy—Evidence and consensus based report

The Evidence-practice Gap in Minimal Intervention Dentistry: An International Comparison Between Dentists in Japan and Brazil

OBJECTIVES

This study was designed to: 1) evaluate and compare the evidence-practice gap (EPG) in minimal intervention dentistry (MID) in Japan and Brazil by measuring concordance between dentists' clinical practice and published evidence; and 2) identify dentists' factors associated with the EPG in both countries.

METHODS

We performed a cross-sectional study using a web-delivered questionnaire among 136 Japanese and 110 Brazilian dentists. The questionnaire consisted of three questions concerning "restoration diagnosis and treatment," "deep caries diagnosis and treatment," and "caries risk assessment" regarding MID. A chi-square test was used to analyze differences in concordance among clinical practice and evidence from the literature between Japanese and Brazilian dentists. Logistic regression analyses were performed to analyze dentists' factors associated with overall concordance for all three questions.

RESULTS

Overall concordance was significantly higher in Brazil (55%) than in Japan (38%) (p<0.01). Concerning how evidence was obtained, textbooks, nonacademic journals, and seminars and workshops were used as information sources more frequently by Japanese than Brazilian dentists (p<0.001), whereas scientific journal articles in English were used more frequently by Brazilian dentists (p<0.001). On logistic regression analysis, overall concordance was higher for Japanese dentists who frequently obtained evidence from scientific journal articles in English (p<0.05), whereas Brazilian dentists who frequently obtained evidence from the Internet were associated with lower overall concordance (p<0.05).

CONCLUSIONS

Because overall concordance was significantly higher in Brazil than in Japan, Japan may have a greater EPG in MID practice. Specific characteristics of Japanese and Brazilian dentists showed significant associations with overall concordance.

A low-shrinkage-stress and anti-bacterial adherent dental resin composite: physicochemical properties and biocompatibility

Polymerisation shrinkage and biofilm accumulation are the two main problems associated with dental resin composites (DRCs) that induce secondary caries, which can cause restoration failure. Polymerisation shrinkage can lead to microleakage gaps between the tooth and the DRCs, causing the aggregation of bacteria and development of secondary caries. Reducing the shrinkage stress (SS) and improving the resistance to bacterial adhesion have always been the focus of this field in modifying DRCs. A thiol-ene resin system can effectively reduce the polymerisation SS via its step-growth mechanism for delaying the gel point. Fluorinated compounds can reduce the surface free energies, thereby reducing bacterial adhesion. Thus, in this study, a range of mass fractions (0, 10, 20, 30, and 40 wt%) of a fluorinated thiol-ene resin system were added to a fluorinated dimethacrylate resin system/tricyclo decanedimethanol diacrylate to create a fluorinated methacrylate-thiol-ene ternary resin matrix. DRCs were prepared using the obtained ternary resin matrix, and their physical and chemical properties, effect on bacterial adhesion, and biocompatibility were investigated. The results demonstrated that the volumetric shrinkage and SS of the DRCs were reduced with no reduction in conversion degree even after the thiol-ene resin system was added. All DRC-based fluorinated resin systems exhibited an excellent anti-bacterial adhesion effect, as evidenced by the colony-forming unit counts, live/dead bacterial staining, and crystal violet staining tests against Streptococcus mutans (S. mutans). The genetic expressions associated with the bacterial adhesion of S. mutans were substantially affected after being cultured with fluorinated DRCs. All fluorinated DRCs demonstrated good biocompatibility through the in vitro cytotoxicity test and live/dead staining images of the L-929 cells. The above results illustrate that the DRCs based on the fluorinated methacrylate-thiol-ene resin matrix can be potentially applied in clinical practice due to their low SS and anti-bacterial adhesion effect.

Clinical Investigation of the Inhibitory Effects of Tooth-Coating Materials on Initial Active Root Caries: A Pilot Randomized Controlled Trial

Background and Objectives: Caredyne ZIF-C is a novel, capsule-mixed zinc-containing prototype glass ionomer cement (GIC). Zinc ions are reported to inhibit root dentin demineralization, dentin collagen degradation, bacterial growth, acid production, and in vitro bacterial biofilm formation. However, the effectiveness of GICs against initial root caries lesions is unclear. Therefore, this study aimed to evaluate the efficacy of GICs, especially the new zinc-containing Caredyne ZIF-C GIC, as tooth-coating materials in patients with initial active root caries. Materials and Methods: A total of 58 lesions in 47 older adults (age > 65 years) were randomly allocated to one of the following three groups: Caredyne ZIF-C, Fuji VII (a conventional GIC), and sodium fluoride (NaF). All the lesions were treated with the assigned materials without removing the infected dentin, and the rates of dental plaque attachment and coating material fall-out were evaluated after 3, 6, and 12 months. The failure rate was defined as the number of teeth that needed restoration due to caries progression. Results: The plaque attachment rates tended to be lower in the material-coated root surfaces than in the healthy exposed root surfaces after 3, 6, and 12 months, although the differences among the three groups were not significant. Moreover, the coating material fall-out rate tended to be lower in the Caredyne ZIF-C group than in the Fuji VII group. There was no significant difference in the failure rate among the three groups at the 12 months mark. Conclusions: Though this pilot study offers a new direction for suppressing the progression of initial active root caries by controlling plaque attachment using GICs including Caredyne ZIF-C, clinical studies with a larger sample size are needed.

Methodological quality of evidence-based clinical practice guidelines in cariology

OBJECTIVE

The present study aimed to appraise the methodological quality of evidence-based Clinical Practice Guidelines (CPGs) in the cariology field.

MATERIALS AND METHODS

A systematic search on electronic databases (MEDLINE/Pubmed, EMBASE, DARE and Epistemonikos), websites, and guideline organizations were undertaken. Evidence-based CPGs including at least one recommendation for clinical prevention and/or management of dental caries, developed for any clinical setting, were included. The quality of each guideline was evaluated using the AGREE II tool. Descriptive analysis was performed and the average overall score for each domain was calculated.

RESULTS

Thirty-two guidelines were included. Most of the CPGs achieved higher scores for the domains of clarity of presentation (66.7%, 95% IC 37.3-52.2) and scope and purpose (59.6%, 95% IC 53.7-65.5) domains; and lower scores for editorial independence (46.1%, 95% IC 37.8-55.7) and applicability domain (44.7%, 95% IC 37-55.3). The reviewers assessed 12 CPGs (37.5%) as recommended for use, 15 (46.9%) recommended with modifications, and 5 (15.6%) as not recommended.

CONCLUSION

The overall methodological quality of evidence-based CPGs in the cariology field is moderate, and there is a need for improvements in reporting related to most domains. The poorest reporting was found in the description of the domains' applicability of its recommendations and editorial independence.

CLINICAL RELEVANCE

Clinical Practice Guidelines provide guidance to patients, healthcare professionals, and stakeholders. The quality of these documents is essential for establishing trust in their recommendations.

Using Antimicrobial Photodynamic Therapy with Ultrasound Devices and Bioactive Glasses as a Combined Approach for Treating Dentin Caries Lesions

Novel approaches for caries lesion removal and treatment have been proposed. This study evaluates the combined use of an experimental ultrasound, aPDT (antimicrobial photodynamic therapy) and bioactive glasses on the removal, decontamination and remineralization of dentin caries lesions. A biological model created with a duo species biofilm (Streptococcus mutans and Lactobacillus acidophilus) was used for the development of a caries-like lesion over the dentin for 7 days. Bovine dentin specimens (4 × 4 × 2 mm) were randomized according to the following caries removal techniques: bur (BUR) or ultrasound (ULT), decontamination (with or without aPDT) and remineralization materials (45S5 or F18 bioactive glasses). The following different groups were investigated: caries lesion (control); sound dentin (control); BUR; BUR + aPDT; ULT; ULT + aPDT; BUR + 45S5, BUR + F18; ULT + 45S5; ULT + F18; BUR + aPDT + 45S5; BUR + aPDT + F18; ULT + aPDT + 45S5; and ULT + aPDT + F18. Transverse microradiography (TMR), cross-sectional microhardness (CSH), FT-Raman spectroscopy and confocal microscopy (CLSM) were performed. A two-way ANOVA and Tukey's test were used (α = 0.05). (3) Results: The TMR revealed a lesion depth of 213.9 ± 49.5 μm and a mineral loss of 4929.3% vol.μm. The CSH increases as a function of depth, regardless of the group (p < 0.05). Removal with BUR (24.40-63.03 KHN) has a greater CSH than ULT (20.01-47.53 KHN; p < 0.05). aPDT did not affect the CSH (p > 0.05). No difference was observed between 45S5 or F18 (p > 0.05), but a change was observed for ULT (p > 0.05). The FT-Raman shows no differences for the phosphate (p > 0.05), but a difference is observed for the carbonate and C-H bonds. The CLSM images show that aPDT effectively inactivates residual bacteria. A combination of ULT, aPDT and bioactive glasses can be a promising minimally invasive treatment.

A Systematic Review of Clinical Practice Guidelines for Caries Prevention following the AGREE II Checklist

Untreated oral diseases are detrimental to overall well-being and quality of life and are in close relationship with social and economic consequences. The presence of strong evidence for caries primary and secondary prevention is a compulsory tool for the development of clinical practice guidelines (CPGs). This paper was aimed to assess systematically the importance of clinical practice guidelines in caries prevention management considering both the adult and pediatric populations and evaluate them using the Appraisal of Guidelines for Research and Evaluation (AGREE II) Checklist. Records were extracted from EMBASE, SCOPUS, PubMed/Medline and seven other relevant guideline databases between 6 January and 14 February 2023. Two reviewers independently conducted the appraisal using the web-based platform My AGREE PLUS. Twenty-one guidelines/papers met the inclusion criteria and were reviewed. Eight CPGs included both primary and secondary prevention interventions, whereas thirteen presented a single preventive model. Overall, 12 guidelines were published in the USA. The mean AGREE II scores ranged from 35.4% to 84.3%. Of the total twenty-one included guidelines, twelve were classified as "Recommended", ranging from 56.3% to 84.3%, the others were described as "Recommended with modification", ranging from 35.4% to 68.9%. From the AGREE II analysis carried out, the CPGs included in this survey adopted a punctual methodological rigor but lacked applicative power. The present survey showed that the public, as the primary beneficiary, played a limited role in the development of the twenty-one CPGs. Hence, methodological improvement can better support high-quality CPG development in the future.

Effect of Antibacterial Agents on Dentin Bond Strength of Bioactive Restorative Materials

Treating dentin surfaces with antibacterial agents prior to bonding bioactive restorations might affect their mechanical properties. In this study, we evaluated the effect of silver diamine fluoride (SDF) and chlorhexidine (CHX) on the shear bond strength (SBS) of bioactive restorative materials. Dentin discs were treated with SDF for 60 s or CHX for 20 s and bonded with four restorative materials, namely Activa Bioactive Restorative (AB), Beautifil II (BF), Fuji II LC (FJ), and Surefil One (SO). Control discs were bonded without treatment (n = 10). SBS was determined using a universal testing machine, and a scanning electron microscope (SEM) was used for the evaluation of the failure mode and the cross-sectional examination of adhesive interfaces. The SBS of each material between different treatments and of the different materials within each treatment were compared via a Kruskal-Wallis test. The SBS of AB and BF was significantly higher than that of FJ and SO in the control and CHX groups (p < 0.01). In the latter, SBS was higher in FJ than SO (p < 0.01). SO had a higher value with SDF compared to CHX (p = 0.01). The SBS of SDF-treated FJ was higher than that of the control (p < 0.01). SEM showed a more homogenous and improved interface of FJ and SO with SDF. Neither CHX nor SDF compromised the dentin bonding of bioactive restorative materials.

Dental Caries and Its Management

Objectives

In recent years, the management of dental caries has evolved significantly. Caries prevention, early detection, and a diagnosis based on risk indicators and risk factor assessments are the most current practical approaches. Furthermore, as proposed in minimally invasive dentistry, the new management approaches preserve healthy tissue and maintain pulp vitality. This article overviews the latest minimally invasive dental caries management and treatment options. The information will assist the reader in the early detection, diagnosis, and treatment of dental caries.

Materials and Methods

The PubMed (MEDLINE) search engine was used to gather the most relevant information on dental caries. The search was restricted to five years (May 30, 2018-May 29, 2022), and only English-language studies were accessed. A Boolean search of the PubMed data set was implemented to combine a range of keywords. The following filters were applied: abstract, free full text, full text, clinical trial, randomised control trial, systematic review, meta-analysis, and review. More studies were also obtained by manual searches from Google Scholar and textbooks on dental caries.

Results

By using this process, 683 articles and studies were obtained. The most relevant published studies were chosen and used in the current review. The selected articles are included in the references list. However, the search extended to cover the last five years as our understanding and management of dental caries have changed significantly.

Conclusions

Early detection and diagnosis of caries based on risk indicators and risk factor assessments are effective. Furthermore, minimally invasive restorative techniques are beneficial in managing dental caries and preserving healthy tissue and should be used whenever possible. This new information, knowledge, and materials should encourage professionals to implement this method. Having a strategy and system based on patient-centred care is critical, and our dental responsibilities must prioritise patient-centred care.

Direct restorations and enhanced caries prevention among 20- to 60-year-olds attending Helsinki City Public Dental Service - a register-based observation

OBJECTIVE

Our retrospective register-based observational study evaluated age-specific aspects and changes in volume and content of direct restorative procedures, pulp cappings and enhanced caries prevention measures given to adults.

METHODS

Data included all treatments provided for 20- to 60-year-olds visiting the Helsinki City Public Dental Service (PDS) in 2012 and 2017. For both years, the data were aggregated into 5-year age groups. Data included means of DMFT indices, number and size of direct restorations, number of specific codes for pulp cappings and enhanced prevention.

RESULTS

Around half of all patients received restorations, 39,820 (50.9%) in 2012 and 43,392 (45.9%) in 2017. The greatest increase in DMFT means by age cohort was found for the 2012 age cohort of 25- to 29-year-olds and the smallest for the 2012 age cohort of 45- to 49-year-olds. In each same-age group and each age cohort, the enhanced prevention in 2017 was less frequent than in 2012. The proportion of two-surface restorations accounted for 44.7% of procedures in 2012 and 45.9% in 2017, followed by an increasing proportion of one-surface restorations, from 28.3% in 2012 to 32.9% in 2017. Associations between restoration size and age group were highly significant (p < .001).

CONCLUSIONS

The volume of direct restorative procedures and enhanced prevention measures were strongly age-dependent. Restorative treatment procedures were more frequent in older age groups than in younger age groups, and vice versa for enhanced prevention and pulp cappings. The magnitude of restorative treatment decreased slowly from 2012 to 2017, and overall enhanced preventive treatment was limited.

Antimicrobial photodynamic therapy as an adjunctive treatment to ultrasound for the dentin caries-like lesion removal

OBJECTIVE

To evaluate in vitro the efficacy of ultrasound device to remove caries-like dentin and the curcumin-mediated antimicrobial photodynamic therapy (aPDT) to decontaminate the affected dentin.

METHODS

Bovine dentin specimens (n = 173) of 4 × 4 × 2 mm were first submitted to Knoop surface microhardness to standardize the specimens (29 ± 3 KHN). Artificial caries lesion was induced by Streptococcus mutans strain by biological model for 7 days. Infected dentin was removed (1 min) with the following techniques: dentin excavator, bur at low-speed rotation and ultrasound device. After that, aPDT application was performed using blue LED under 460 nm. Polarized light microscopy (PLM), removal rate (n = 10), cross-sectional microhardness (n = 10), colony forming units per milliliter (CFU) (n = 9) and confocal laser microscopy (CM) (n = 2) were performed. ANOVA with Welch correction, post-hoc Games-Howell and two-way ANOVA followed by Tukey's post-hoc tests were used.

RESULTS

PLM confirmed the caries lesion formation with a depth of ∼147.9 µm. Groups treated with ultrasound showed lower removal rate (p = 0.001). Regardless of the treatment, the microhardness values increased as function of depth (p ≤ 0.05). Carbide bur showed the highest microhardness value, followed by ultrasound and excavator. CFU and CM showed a significant reduction in S. mutans after aPDT application.

CONCLUSION

Ultrasound was efficient, since it removed infected dentin, preserving the affected dentin and aPDT can be used as a complementary therapy to decontaminate the affected dentin.

CLINICAL SIGNIFICANCE

Ultrasound device may help the clinician to remove dentin caries-like lesions since it is a conservative technique and provided the removal of infected dentin, preserving the affected dentin. aPDT application may be used as a complimentary technique to promote antibacterial effect and possibly minimize the risk of secondary caries.

The Effect of Morpholine on Composite-to-Composite Repair Strength Contaminated with Saliva

The aim of this study was to specifically explore the effects of morpholine on chemical surface treatments of aged resin composites contaminated with saliva to new resin composite repair strength. One hundred and thirty five resin composite specimens were fabricated and thermocycled to replicate an aged resin composite. These aged resin composites were randomly separated into nine groups (n = 15) depending on the various surface contaminants and surface treatment techniques. These groups were as follows: group 1—no surface treatment; group 2—no saliva + adhesive agent; group 3—no saliva + morpholine + adhesive agent; group 4—no saliva + morpholine; group 5—saliva; group 6—saliva + adhesive agent; group 7—saliva + morpholine + adhesive agent; group 8—saliva + morpholine; and group 9—saliva + phosphoric acid + adhesive agent. A mold was covered on the top of the specimen center and then filled with resin composite. The shear bond strengths and failure modes were examined. The collected data was analyzed using one-way ANOVA, and the significance level was determined using Tukey’s test. Group 5 (3.31 ± 0.95 MPa) and group 6 (4.05 ± 0.93 MPa) showed the lowest bond strength statistically, while group 3 (23.66 ± 1.35 MPa) and group 7 (22.88 ± 1.96 MPa) showed the most significantly high bond strength. The bond strength in group 2 (16.41 ± 1.22 MPa) was significantly different from that in group 1 (9.83 ± 1.13 MPa), group 4 (10.71 ± 0.81 MPa), and group 8 (10.36 ± 1.53 MPa), while group 9’s (17.31 ± 1.48 MPa) SBS was not significantly different. In conclusion, the application of morpholine on aged resin composite with or without contamination with saliva prior to the application of the adhesive agent increased the bond strength of aged resin composite repaired with new resin composite (p < 0.05).

Silver diamine fluoride therapy for dental care

Silver diamine fluoride (SDF) was developed in Japan in the 1960s. It is used to control early childhood caries, arrest root caries, prevent fissure caries and secondary caries, desensitise hypersensitive teeth, remineralise hypomineralised teeth, prevent dental erosion, detect carious tissue during excavation and manage infected root canals. SDF is commonly available as a 38% solution containing 255,000 ppm silver and 44,800 ppm fluoride ions. Silver is an antimicrobial and inhibits cariogenic biofilm. Fluoride promotes remineralisation and inhibits the demineralisation of teeth. SDF also inactivates proteolytic peptidases and inhibits dentine collagen degradation. It arrests caries without affecting dental pulp or causing dental fluorosis. Indirect pulp capping with SDF causes no or mild inflammatory pulpal response. However, direct application of SDF to dental pulp causes pulp necrosis. Furthermore, SDF stains carious lesions black. Patients must be well informed before SDF treatment. SDF therapy is simple, painless, non-invasive, inexpensive, and requires a simple armamentarium and minimal support. Both clinicians and patients generally accept it well. In 2021, the World Health Organization included SDF as an essential medicine that is effective and safe for patients. Moreover, it can be used for caries control during the COVID-19 pandemic because it is non-aerosol-generating and has a low risk of cross-infection.

Comparison of Cariostatic and Remineralizing Potential of Two Commercial Silver Diamine Fluoride Preparations using Confocal Laser Microscopy and EDX-SEM Spectroscopy: An In Vitro study

Aim

To investigate the cariostatic and remineralizing effect of two commercial silver diamine fluoride (SDF) preparations on enamel and dentinal caries using a bacterial plaque model.

Materials and methods

A total of 32 extracted primary molars were divided into two groups (n = 16), group I (FAgamin), and group II (SDF). Plaque bacterial model was used to induce caries on enamel and dentin. Preoperative evaluation of samples was done using confocal laser microscopy (CLSM) and energy-dispersive X-ray spectroscopy-scanning electron microscope (EDX-SEM). All samples were treated with test materials and evaluated for postoperative remineralization quantification.

Results

Energy-dispersive X-ray spectroscopy (EDX) revealed that mean preoperative levels (in weight %) of silver (Ag) and fluoride (F2) in carious enamel lesions were 0.0 and 0.0, which increased postoperatively to 11.40 and 31.05 for FAgamin and 13.61 and 31.87 for SDF, respectively. For dentinal caries, EDX revealed mean preoperative levels (in weight %) of Ag and F2 were 0.0 and 0.0, which increased to 11.47 and 48.71 for FAgamin and 10.16 and 47.82 for SDF, respectively postoperatively. Both the groups showed evident demineralization with exposed collagen under SEM. The mean value of enamel lesion depth for the group I and II were 38.64 and 39.30 µm, that reduced to 28.02 and 28.70 µm while for dentinal caries, the mean depth from 38.05 and 38.29 µm that reduced significantly to 28.96 and 30.10 µm, respectively (p < 0.001). Caries depth declined significantly after the application of both FAgamin and SDF (p < 0.001).

Conclusion

FAgamin and SDF show similar cariostatic and remineralization potential for dental caries. The bacterial plaque model used in this study is an efficient method to induce artificial carious lesions in teeth.

Clinical significance

A comparative evaluation of these two cariostatic and remineralizing agents will aid in identifying the efficacy of both commercial products in treating initial caries lesions in an effective noninvasive and child-friendly manner.

How to cite this article

Kale YJ, Misal S, Dadpe MV, et al. Comparison of Cariostatic and Remineralizing Potential of Two Commercial Silver Diamine Fluoride Preparations using Confocal Laser Microscopy and EDX-SEM Spectroscopy: An In Vitro study. Int J Clin Pediatr Dent 2022;15(6):643-651.

Comparative Evaluation of Cariostatic and Remineralizing Potential of Two Commercial Silver Diamine Fluoride Preparations Using Confocal Laser Microscopy and EDX-SEM Spectroscopy: An In Vitro Study

Aim

To investigate the cariostatic and remineralizing effect of two commercial silver diamine fluoride (SDF) preparations on enamel and dentinal caries using a plaque bacterial model.

Materials and methods

Thirty-two extracted primary molars were divided into two groups (n = 16) as group I (Advantage Arrest) and group II (e-SDF). Plaque bacterial model was used to induce caries on enamel and dentin. Preoperative evaluation of samples was done using confocal laser scanning microscopy (CLSM) and energy-dispersive X-ray spectroscopy-scanning electron microscope (EDX-SEM). All samples were treated with test materials and evaluated for postoperative remineralization quantification.

Results

EDX revealed that mean preoperative levels (in weight%) of silver (Ag) and fluoride (F) in enamel carious lesions were 0.0 and 0.0, which increased postoperatively to 11.40 and 31.05 for Advantage Arrest and 13.61 and 31.87 for e-SDF, respectively. For dentinal caries, EDX revealed mean preoperative levels (in weight%) of Ag and F were 0.0 and 0.0, which increased to 11.47 and 48.71 for Advantage Arrest and 10.16 and 47.82 for e-SDF, respectively postoperatively. Both groups showed evident demineralization with exposed collagen under SEM. The mean values of enamel lesion depth for the group I and II were 38.64 and 39.30 µm, that reduced to 28.02 and 28.70 µm, while for dentinal caries, the mean depth from 38.05 to 38.29 µm that reduced significantly to 28.96 and 30.10 µm, respectively (p < 0.001). Caries depth declined significantly after the application of both Advantage Arrest and e-SDF (p < 0.001).

Conclusion

Advantage arrest and e-SDF show similar cariostatic and remineralization potential for dental caries. The plaque bacterial model used in this study is an efficient method to induce artificial carious lesions in teeth.

How to cite this article

Kale YJ, Misal S, Dadpe M, et al. Comparative Evaluation of Cariostatic and Remineralizing Potential of Two Commercial Silver Diamine Fluoride Preparations Using Confocal Laser Microscopy and EDX-SEM Spectroscopy: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(4):442-449.

Exploring variation of coverage and access to dental care for adults in 11 European countries: a vignette approach

BACKGROUND

Oral health, coupled with rising awareness on the impact that limited dental care coverage has on oral health and general health and well-being, has received increased attention over the past few years. The purpose of the study was to compare the statutory coverage and access to dental care for adult services in 11 European countries using a vignette approach.

METHODS

We used three patient vignettes to highlight the differences of the dimensions of coverage and access to dental care (coverage, cost-sharing and accessibility). The three vignettes describe typical care pathways for patients with the most common oral health conditions (caries, periodontal disease, edentulism). The vignettes were completed by health services researchers knowledgeable on dental care, dentists, or teams consisting of a health systems expert working together with dental specialists.

RESULTS

Completed vignettes were received from 11 countries: Bulgaria, Estonia, France, Germany, Republic of Ireland (Ireland), Lithuania, the Netherlands, Poland, Portugal, Slovakia and Sweden. While emergency dental care, tooth extraction and restorative care for acute pain due to carious lesions are covered in most responding countries, root canal treatment, periodontal care and prosthetic restoration often require cost-sharing or are entirely excluded from the benefit basket. Regular dental visits are also limited to one visit per year in many countries. Beyond financial barriers due to out-of-pocket payments, patients may experience very different physical barriers to accessing dental care. The limited availability of contracted dentists (especially in rural areas) and the unequal distribution and lack of specialised dentists are major access barriers to public dental care.

CONCLUSIONS

According to the results, statutory coverage of dental care varies across European countries, while access barriers are largely similar. Many dental services require substantial cost-sharing in most countries, leading to high out-of-pocket spending. Socioeconomic status is thus a main determinant for access to dental care, but other factors such as geography, age and comorbidities can also inhibit access and affect outcomes. Moreover, coverage in most oral health systems is targeted at treatment and less at preventative oral health care.

Ceramic Inlay Bonded Interfaces in Minimally Invasive Preparations: Damage and Contributing Mechanisms in Sliding Contact

BACKGROUND

In the preparation of inlay cavities, a choice must be made between conventional standard and minimally invasive preparation designs; in the long run, this choice can affect the integrity of the bonded interface.

PURPOSE

To evaluate the effect of minimally invasive cavity preparation designs on the extent and contributing mechanisms of damage to ceramic inlay bonded interfaces.

METHODS AND MATERIALS

Tooth blocks with 90°, 120° and 75° marginal angles were prepared, representing tooth cavities with conventional standard and minimally invasive preparations with large divergence and convergence angles and bonded to monolithic ceramic (IPS e.max CAD). Vickers indentations were placed at various distances from the bonded interface. The indentation morphology and crack length were observed. Reciprocating wear tests were performed on the bonded interface with a 20-newton (N) vertical load. The wear depth and wear-scar morphology were characterized after increments of cyclic sliding contact.

RESULTS

The 120° group exhibited longer indentation cracks in the ceramic, whereas the 75° group showed larger indentations in the enamel when compared to the 90° group (p<0.001). Consistent with the weaker edge crack resistance, the 120° group experienced the greatest wear (p=0.008), and the wear depth in the enamel of the 75° group exceeded that of the 90° group (p<0.001) in the early stage (5×102 cycles). However, no significant difference in the wear depth (p>0.147) and morphology were found at the later wear stage among the three groups.

CONCLUSION

Within the limitations of this study, minimally invasive preparations with 120° and 75° marginal angles can result in early sever damage at the ceramic inlay bonded interface but show comparable wear behaviors to the conventional 90° group at the later stage.

CHX Stabilizes the Resin/demineralized Dentin Interface

The aim of this study was to evaluate the effect of 2% chlorhexidine digluconate (CHX) on microtensile bond strength (µTBS) between an adhesive system and under 3 dentin conditions. For that, this study evaluated the adhesive interface at initial, after 6 months and 1 year of storage. Forty-eight human third molars were prepared and randomly divided into 3 groups, according to dentin substrates: sound dentin (Sd), caries-infected dentin (Ci) and caries-affected dentin (Ca). The groups were subdivided into two according to the dentin pre-treatment: application of 2% CHX or without pre-treatment (control). The dentin surfaces were etched with 35% phosphoric acid gel and bonded with Adper Single Bond 2 (3M ESPE) adhesive system according to manufacturer's instructions. Subsequently, the specimens were stored in deionized water at 37°C for 24h, 6 months and 1 year. Two additional teeth were used to analyze the bonding interfaces by SEM. Data was submitted to three-way ANOVA in a split plot design and Tukey's test (α = 0.05). The results showed that Ci decreased µTBS values when compared to Ca and Sd, regardless storages time or treatment. Stored samples for 6 months and 1 year decreased the µTBS for the control group, but no difference was found between storages time for the CHX group. As a conclusion, the 2% CHX application after etching showed improved dentin bond strength in the storage time, regardless of the substrates evaluated.

Perspective and practice of root caries management: a multicountry study - Part I

Background:

Every effort needs to be made to better understand the current state of practice and trends relating to root caries management which will be of benefit to dentists universally in the practice of dentistry.

Aim:

This article presents a multicountry questionnaire survey of the current state of practice in the management of root caries among dentists in nine different countries to get a wider range of opinions and perspectives.

Methodology:

A questionnaire related to root surface caries was distributed among practicing dentists in nine different countries, namely the United Kingdom, Libya, Jordan, Saudi Arabia, Egypt, Brazil, India, Malaysia, and Iraq. Questionnaire responses were analyzed, and the results were compared among groups.

Results:

The results showed statistically significant differences among dentists in most questionnaire aspects. Bleeding is the greatest obstacle facing dentists when restoring root surface lesions. Reported survival rates reflect uncertainty about the material and/or approach of choice in the management of root surface caries.

Conclusion:

This questionnaire survey revealed the current status of management of root surface caries in clinical practice in various countries. Substantial attention is required to bridge the knowledge gap and address the current void of uncertainty as relates to root caries management by providing a common ground for communication between dentists from all around the globe. In all, this work found a degree of consensus at the international level on what appears to work well among the dental practices surveyed and identified several issues with existing approaches that need to be addressed in future studies.

Web-based intervention to improve the evidence-practice gap in minimal intervention dentistry: Findings from a dental practice-based research network

OBJECTIVES

To determine whether: the evidence-practice gap (EPG) in minimal intervention dentistry (MID) can be improved by a tailored web-based intervention, and specific clinical situations might impede implementing MID.

METHODS

We conducted a before-after intervention study and a qualitative study. Two web-based questionnaire surveys were conducted among 197 Japanese dentists. In the first questionnaire, a baseline EPG was measured using six questionnaire items. Subsequently, feedback material about the EPG was electronically prepared, including results of the first questionnaire, international comparisons with a previous study from the US, and a summary of recent evidence on MID. In the second questionnaire, the EPG was re-measured after participants read the material. The primary outcome was mean overall concordance between published evidence and the dentist's clinical practice for all six questions. During the second questionnaire, we performed qualitative content analysis using free-text responses to a question about difficult situations encountered when conducting MID.

RESULTS

Regarding before and after comparisons of concordance between the first and second questionnaires, mean overall concordance improved significantly, from 66% to 89% (p<0.001). Qualitative content analysis identified five difficult situations: "cases where decision making for treatment and prognosis is difficult", "inadequate practice resources", "limitations on patient visit and treatment period", "discrepancy between MID and the patient's values", and "limitations on health insurance and social understanding".

CONCLUSIONS

These results suggest that it is possible to reduce the EPG in MID using a web-based educational intervention among Japanese dentists. Qualitative content analysis revealed five difficult situations that might hinder implementation of MID.

CLINICAL SIGNIFICANCE

Although this intervention demonstrated educational effects, perfect concordance was not achieved by all participants. This is possibly associated with the five situations that participants reported facing when conducting MID. Creating an environment to improve these situations may facilitate a reduction in the EPG.

Concentrated MTA Repair HP reduced biofilm and can cause reparative action at a distance

AIM

To evaluate in vitro whether MTA Repair HP can induce repair processes at a distance, including its effects on biofilm, cell viability, migration, production of TGF-β, phosphate and ALP, evaluated through MTA diluted extracts.

METHODOLOGY

Initially, antibacterial tests were performed with the bacterium Streptococcus mutans (ATCC 25175) in the presence of MTA extracts (dilutions of 1:1, 1:2 and 1:4). Growth inhibition assay by microdilution in broth, antibiofilm plate assay of young biofilm and antibiofilm assay in confocal microscopy of mature biofilm were carried out. Then, pulp cells were stimulated in the presence of several MTA dilutions, and cell viability (MTT assay), proliferation and migration capacity (scratch assay) were evaluated. To evaluate the capacity of 1:1, 1:2 and 1:4 dilutions of MTA Repair HP to promote the production of important agents of odontogenic differentiation and mineralization, ALP activity, TGF-β secretion and phosphate quantification were measured. Statistical differences were verified using one-way and two-way anova and Tukey's post-tests.

RESULTS

The test dilutions of MTA Repair HP did not inhibit planktonic S. mutans growth but were able to reduce young and mature S. mutans biofilm (p < 0.001). In addition, none of the MTA Repair HP dilutions was cytotoxic for pulp cells. The 1:2 and 1:4 dilutions of MTA Repair HP induced migration and proliferation of pulp cells (p < 0.05). ALP activity and TGF-β secretion were independent of the tested dilution (p < 0.001). Diluted 1:4 MTA Repair HP produced less phosphate than the more concentrated 1:1 and 1:2 MTA dilutions (p < 0.001).

CONCLUSIONS

Undiluted MTA Repair HP reduced S. mutans biofilm, when compared to 1:2 and 1:4 MTA dilutions. Furthermore, none of the tested dilutions was cytotoxic to pulp cells. MTA Repair HP promoted cell migration and proliferation at a distance, assessed through the dilution of the MTA. Even from a distance, MTA Repair HP has the ability to participate in some events related to repair, such as migration, proliferation and TGF production.

Reversal of Root Caries with Casein Phosphopeptide-Amorphous Calcium Phosphate and Fluoride Varnish in Xerostomia

Different formulas of topical fluoride have been used to manage root carious lesions. This clinical trial aimed to investigate the efficacy of a dental varnish containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride compared with fluoride alone in reversing/arresting root caries in xerostomic patients over 1 year. A total of 80 patients (age range 45-92 years) with primary root caries (n = 184 root carious lesions) and unstimulated salivary flow rate of <0.2 mL/min were randomly allocated to receive either dental varnish containing CPP-ACP and 5% fluoride (group 1: MI varnish; GC, Japan) (n = 41, 83 lesions), or dental varnish with 5% fluoride alone (group 2: NUPRO White; Dentsply, USA) (n = 39, 101 lesions). Clinical assessments with Severity Index (SI) for root caries, DIAGNOdent measurements, and varnish application were carried out at baseline, 3, 6, and 12 months. Standard oral hygiene instructions with 1,450 ppm fluoride toothpastes were provided for both groups. After 3 months, 63.9% (n = 46) of root caries in group 1 became hard (SI: 0) compared with 39.3% (n = 35) in group 2 (p < 0.01). After 6 and 12 months, the differences in SI were insignificant (group 1, n = 60, 83.3%) (group 2, n = 66, 74.2%) (p = 0.36), and (group 1, n = 60, 89.6%) (group 2, n = 67, 81.7%, n = 1 soft, 1.2%) (p = 0.29), respectively. In both groups, noncavitated leathery lesions were more likely to become hard when compared to the cavitated root caries. A significant decrease in plaque index, surface roughness, lesion dimension, and DIAGNOdent readings with a significant increase in lesion distance from the gingival margin was reported in both groups (p < 0.05). This study has provided evidence that fluoride dental varnish either with or without calcium and phosphate has the potential to arrest/reverse root caries, especially noncavitated lesions for patients with xerostomia.

Global Oral Health Policies and Guidelines: Using Silver Diamine Fluoride for Caries Control

Silver diamine fluoride (SDF) was developed in Japan in the 1960s. It is a clear solution containing silver and fluoride ions. Because of its anti-bacterial and remineralizing effect, silver diamine fluoride has been used in managing dental caries for decades worldwide. This paper aims to summarize and discuss the global policies, guidelines, and relevant information on utilizing SDF for caries management. SDF can be used for treating dental caries in most countries. However, it is not permitted to be used in mainland China. Several manufacturers, mainly in Australia, Brazil, India, Japan, and the United States, produce SDF at different concentrations that are commercially available around the world. The prices differ between contents and brands. Different government organizations and dental associations have developed guidelines for clinical use of SDF. Dental professionals can refer to the specific guidelines in their own countries or territories. Training for using SDF is part of undergraduate and/or postgraduate curriculums in almost all countries. However, real utilization of SDF of dentists, especially in the private sector, remains unclear in most places because little research has been conducted. There are at least two ongoing regional-wide large-scale oral health programs, using SDF as one of the components to manage dental caries in young children (one in Hong Kong and one in Mongolia). Because SDF treatment does not require caries removal, and it is simple, non-invasive, and inexpensive, SDF is a valuable strategy for caries management in young children, elderly people, and patients with special needs. In addition, to reduce the risk of bacteria or virus transmission in dental settings, using SDF as a non-aerosol producing procedure should be emphasized under the COVID-19 outbreak.

Potential use of silver diammine fluoride in detection of carious dentin

This study aimed to examine whether discoloration of carious dentin after silver-diammine-fluoride (SDF) application might be used as a mean to detect demineralized-dentin. Fourty specimens were obtained from 20 human permanent teeth. Teeth were sectioned through the center of carious lesions to create 2-halves in which each half was assigned to a treatment group. Specimens were divided into two groups (n=20) (each half was assigned to one group) according to solution, namely Caries Check (CC), or SDF. SDF group was subdivided into 2 groups: light-cured and 2-day storage groups. The specimens were tested using light-microscope, microhardness test and SEM/EDS analysis. Repeated-measures ANOVA was used for statistical analysis. The light-microscope showed superficial discoloration in the CC-group while SDF (2-day storage) group showed deeper discoloration for the lesion area. SDF showed significant increase in the hardness compared with the CC-group. SDF showed potentiality to be used as an assisting-tool for caries detection.

Effects of Various Antioxidant Pretreatment Modalities on Adhesion to Sound and Caries-Affected Dentin: An In Vitro Study

Aim:

Natural antioxidants were offered as the answer of dentin adhesion issue. The aim of this study is to investigate the effects of proanthocyanidin and lycopene as pretreatment agents on the sound and caries-affected dentin surface on microtensile bond strength and microleakage.

Materials and Methods:

This study was designed as in vitro because of that 84 mandibular molar teeth were collected. Forty-two of the included teeth were carious teeth, while the other 42 were without caries. Sixty of them were used for microleakage and 24 for microtensile bond strength testing and scanning electron microscopy analysis. The samples were divided into six subgroups randomly according to dentin pretreatments: 5% proanthocyanidin, 5% lycopene, and no antioxidant application. After the restorative procedures, samples were attached to the microtensile tester. Samples were subjected to tensile stress in the load cell until they broke at a speed of 0.5 mm per min. Microtensile bond strength (µTBS) and microleakage test data were analyzed with two-way analysis of variance, Bonferroni correction, and Tamhane’s T2 tests.

Results:

Two-way variance analysis showed that dentin pretreatment applications, dentin substrate, and the interaction between these two parameters had statistically significant effects on µTBS values ( P < .001). There was no difference between dentin pretreatment applications in terms of microleakage scores ( P > .05).

Conclusion:

The application of dentin pretreatment with proanthocyanidin is a successful procedure that increases the bond strength in both dentin substrate, while pretreatment with lycopene in caries-affected dentin reduces it.

Pulp survival after composite resin restoration of caries lesions in adults

Minimal intervention is generally achieved by using direct composite resin (CR) restorations. However, deep caries lesions may lead to pulpal complications. This study evaluated the risk of endodontic complications after CR restoration in relation to depth of caries lesions. Data on 507 teeth from 316 adults treated with CR were analyzed. Caries depth was expressed as a percentage of the distance between the outer edge of the dental enamel and the pulp base on preoperative radiographs. The interval between CR restoration and follow-up root canal treatment was obtained from electronic treatment records for a period of 24 months. A Cox proportional hazards model was used to investigate the association between risk of endodontic complications and caries depth. Sixteen teeth (3.2%) required root canal treatment within 24 months. No root canal treatment was required after CR treatment for caries affecting <50% of the outer edge of enamel and pulp. As compared with CR treatment of caries lesions with a size of <80%, there was a significantly higher risk of root canal treatment for caries lesions with a size of 80% to 89% (hazard ratio, [95% CI]: 34.68 [4.23-284.11]) and ≥90% (92.01 [10.36-817.41], respectively).

In vitro antibacterial activity and durability of a nano-curcumin-containing pulp capping agent combined with antimicrobial photodynamic therapy

BACKGROUND

Considering the antibacterial properties of nano-curcumin (nCur) reinforced with antimicrobial photodynamic therapy (aPDT), this study aimed to assess the antibacterial activity and durability of Activa BioActive Base/Liner (ABBL) containing nCur (nCur-ABBL) as a pulp capping agent against Streptococcus mutans, the most common cause of secondary caries.

MATERIALS AND METHODS

In this in vitro experimental study, ABBL discs containing 0.5 %, 1%, 2%, and 5% (w/w) concentrations of nCur were fabricated. After aPDT using light emitting diode (LED) at 435 ± 20 nm wavelength for 5 min, the discs were undergone aging in artificial saliva for 90 days. The antibacterial activity of the discs against S. mutans was evaluated by the disc agar diffusion test, and the number of bacterial colonies present in the biofilm formed on the disc surfaces was counted after 0, 15, 30, and 60 days of aging.

RESULTS

The maximum growth inhibition zone was noted around the 5% nCur-ABBL discs. Increasing the concentration of nCur from 0.5 % to 5% combined with aPDT significantly decreased the number of S. mutans colonies in the biofilm over time (P < 0.05). nCur-ABBL discs containing 2% and 5% nCur had no difference in antibacterial activity at any time point up to 60 days (P > 0.05).

CONCLUSION

According to our data, 5% nCur-ABBL revealed the largest growth inhibition zone in S. mutans culture. Moreover, 5% nCur can serve as an excellent ABBL additive in aPDT producer against S. mutans biofilms up to 60 days of aging period.

Evidence-practice gap in minimal intervention dentistry: Findings from a dental practice-based research network

OBJECTIVES

This study aimed to 1) quantify the evidence-practice gap (EPG) between dental clinical practice and published evidence on Minimal Intervention Dentistry (MID) among dentists in Japan; and 2) examine the hypothesis that dentist characteristics have a significant association with the EPG.

METHODS

We conducted a cross-sectional study via use of a web-based questionnaire survey of dentists who were affiliated with the Dental Practice-based Research Network Japan (n = 297). To quantify the EPG on MID, we used a questionnaire that included 10 clinical questions or scenarios to assess concordance between dental practice and published evidence on MID. We evaluated concordance by coding responses to each question as consistent or inconsistent with the evidence. An overall concordance was then determined as percent of responses that were consistent with published evidence for 10 questions. Subsequently, multiple logistic regression analysis was conducted to examine the associations between dentist characteristics and higher overall concordance (≥median) with published evidence.

RESULTS

Mean and median overall dentist-level concordance were both 60 % (SD: 18, interquartile range: 50-75 %). Logistic regression analysis showed that "gender of dentist", "city population", and "frequency of obtaining evidence from the scientific journal articles in English" were significantly associated with high concordance, with odds ratios (95 % CIs) of 2.33 (1.01-5.39), 2.01 (1.02-3.96), and 2.45 (1.08-5.59), respectively.

CONCLUSIONS

Japanese dentists demonstrated medium concordance with published evidence, indicating that an EPG on MID exists in Japanese dental clinical practices. Dentist-specific characteristics had significant associations with high concordance with published evidence.

CLINICAL SIGNIFICANCE

Despite the establishment and dissemination of the concept of MID, the EPG on MID exists in Japanese dental clinical practices. A high concordance was significantly associated with the following dentist characteristics: "female dentist", "dental clinic location in a government-ordinance-designated city", and "frequently obtaining evidence from the English-language scientific journal articles".

Effect of a novel glass ionomer cement containing fluoro-zinc-silicate fillers on biofilm formation and dentin ion incorporation

OBJECTIVES

This study is aimed at evaluating the effect of a new glass ionomer cement (GIC) containing fluoro-zinc-silicate fillers on biofilm formation and ion incorporation.

MATERIALS AND METHODS

Streptococcus mutans biofilms were developed on two GIC materials: Caredyne Restore (CD) and Fuji VII (FJ); and hydroxyapatite (HA) for 24 h at 37 °C using a flow cell system. The morphological structure and bacterial viability were analyzed using a confocal laser scanning microscopy. Bacterial adhesion during the initial 2 h was also assessed by viable cell counting. To study the ion incorporation, restored cavities prepared on the root surfaces of human incisors were subjected to the elemental mapping of the zinc and fluoride ions in the GIC-dentin interface using a wavelength-dispersive X-ray spectroscopy electron probe microanalyzer.

RESULTS

Morphological observations revealed that biofilm formation in the CD group was remarkably inhibited compared with the HA and FJ groups, exhibiting sparse, thinner biofilm clusters. The microorganisms adhering to the CD group were significantly inhibited, revealing 2.9 ± 0.4 for CD, 4.9 ± 0.2 for FJ, and 5.4 ± 0.4 log colony-forming units (CFU) for HA. The CD zinc ion incorporation depth was 72.2 ± 8.0 μm. The fluoride penetration of CD was three times deeper than that of FJ; this difference was statistically significant (p < 0.05).

CONCLUSIONS

Enhanced by the incorporation of zinc and fluoride ions, the new GIC inhibited biofilm formation by interfering with bacterial adhesion.

CLINICAL RELEVANCE

A novel GIC comprised of fluoro-zinc-silicate fillers may improve clinical outcomes, such as root caries and minimally invasive dentistry.

A review of the literature on the efficacy of mineral trioxide aggregate in conservative dentistry

The aim of this literature review was to assess the clinical performance of MTA to establish the evidence level for its effectiveness in vital pulp therapy, perforation repair, and retrograde root canal filling. A comprehensive literature survey was performed via electronic databases of PubMed/MEDLINE. A total of 58 papers were reviewed in this study, of which 2 were systematic reviews/meta-analysis, 9 were randomized controlled trials (RCTs), and the rest were fallen into other categories. Mineral trioxide aggregate (MTA) provided better pulp protection as a direct capping material when compared with calcium hydroxide. As perforation repair materials, MTA demonstrated an excellent sealing ability in vitro. For periodontal tissues around a perforation, MTA provided normal healing processes in clinical trials. It is therefore concluded that MTA has a high potential in repairing perforations. MTA is the most promising material when used for retrograde root canal filling demonstrating normal healing in short/long term clinical outcomes.

Dentists' practice patterns of treatment for deep occlusal caries: Findings from a dental practice-based research network

OBJECTIVES

This study quantified and compared practice patterns of treatment for deep occlusal carious lesions among Japanese dentists, and tested the hypothesis that dentist characteristics are significantly associated with the decision to choose an indirect pulp capping (IPC), a form of selective carious tissue removal that involves leaving a thin layer of demineralized tissue over the pulp, that is then covered with a protective liner.

METHODS

This cross-sectional study was conducted using a questionnaire survey of dentists affiliated with the Dental Practice-based Research Network Japan (n = 297). Dentists were asked to indicate what percentage of time they use three treatment options when treating patients with deep occlusal caries and possible mild pulpitis on a posterior tooth. Response options were "1. Stop before removing all caries and perform an IPC", "2. Remove all caries and proceed with a direct pulp cap", and "3. Remove all caries and proceed with endodontic-related procedures". Percentages of options 1-3 were compared by multiple comparison. Associations between dentist characteristics and a higher percentage of IPC provision (option 1) were analyzed via logistic regression.

RESULTS

Responses were obtained from 206 dentists. Median percentages (interquartile ranges) of options 1, 2 and 3 were 30% (10-59%), 10% (0-30%), and 40% (19-80%), respectively. The differences between option 3 and options 1 and 2 were significant (p < 0.001). In logistic regression analysis, a higher frequency of obtaining evidence from English-language scientific articles was significantly associated with a higher percentage of IPC, with an odds ratio of 2.28 (95%CI: 1.14-4.54).

CONCLUSIONS

Endodontic-related procedures remain the most frequent treatment option for deep occlusal caries. Frequent use of evidence-based information in English-language scientific articles was associated with Japanese dentists' preference toward IPC.

CLINICAL SIGNIFICANCE

Japanese dentists would most frequently choose endodontic-related procedures, followed by IPC and direct pulp capping for treatment of patients with deep occlusal caries with possible mild pulpitis on posterior teeth. Significant association was identified between use of evidence-based information in the English-language scientific literature and Japanese dentists' preference for IPC.

The repair bond strength to resin matrix in cured resin composites after water aging

The repair microshear bond strengths (µSBSs) to resin matrices in 4 different cured-composites after water storage (0, 60 s, 1 week, 1 month) were evaluated. Three different adhesive application methods to the cured-composites were performed; (1) none, (2) onestep self-etch adhesive application, and (3) one-step self-etch adhesive application with a silane coupling agent. Degree of conversion (DC) of the composite discs was determined using ATR/FT-IR with a time-based spectrum analysis. Initially, the amount of un-reacted resin monomers in the repaired cured-composite contributed to the bonding performance of newly-filled uncured-composite to resin matrix of the cured-composite. Adhesive application could not improve their repair µSBS. After 1-month of water-storage, the repair µSBS was dependent on material, which either reduced or did not and was not influenced by their amount of un-reacted resin monomers. When repairing aged composite resin, the appropriate adhesive application procedures were different among resin composites.

Evaluation of discoloration of sound/demineralized root dentin with silver diamine fluoride: In-vitro study

The objective was to evaluate the effect of application of silver diamine fluoride (SDF) on discoloration of demineralized dentin over time. Dentin specimens were divided into four groups according to time of dentin demineralization. A 38% SDF solution was then applied to the dentin surfaces. Half of the specimens were placed in light-proof boxes while the remainder were exposed to light. Both groups were maintained at 37˚C. Color change was determined using a spectrophotometer at different time intervals. SEM/EDS analysis were also undertaken. The 13 h EDTA demineralized group showed the highest values for color change among different time intervals, with the control being the lowest. The light exposed groups showed more color change compared to the unexposed groups. We concluded that the degree of dentin demineralization leads to a significant increase of the rate of dentin color change after application of SDF.

Effect of cavity preparation design and ceramic type on the stress distribution, strain and fracture resistance of CAD/CAM onlays in molars

Objective

This study aimed to evaluate the effect of the cavity preparation and ceramic type on the stress distribution, tooth strain, fracture resistance and fracture mode of human molar teeth restored with onlays.

Material and Methods

Forty-eight molars were divided into four groups (n=12) with assorted combinations of two study factors: BL- conventional onlay preparation with boxes made from leucite ceramic (IPS-Empress CAD, Ivoclar Vivadent); NBL- conservative onlay preparation without boxes made from leucite ceramic; BD- conventional onlay preparation with boxes made from lithium disilicate glass ceramic (IPS e.max CAD, Ivoclar Vivadent); NBL- conservative onlay preparation with boxes made from lithium disilicate glass ceramic cuspal deformation (µS) was measured at 100 N and at maximum fracture load using strain gauge. Fracture resistance (N) was measured using a compression test, and the fracture mode was recorded. Finite element analysis was used to evaluate the stress distribution by modified von Mises stress criteria. The tooth strain and fracture resistance data were analyzed using the Tukey test and two-way ANOVA, and the fracture mode was analyzed by the chi-square test (α=0.05).

Results

The leucite ceramic resulted in higher tooth deformation at 100 N and lower tooth deformation at the maximum fracture load than the lithium disilicate ceramic (P<0.001). The lithium disilicate ceramic exhibited higher fracture resistance than the leucite ceramic (P<0.001). The conservative onlay resulted in higher fracture strength for lithium disilicate ceramic. Finite element analysis results showed the conventional cavity preparation resulted in higher stress concentration in the ceramic restoration and remaining tooth than the conservative onlay preparation. The conservative onlays exhibited increased fracture resistance, reduced stress concentration and more favorable fracture modes.

Conclusion

Molars restored with lithium disilicate CAD-CAM ceramic onlays exhibited higher fracture resistance than molars restored with leucite CAD-CAM ceramic onlays.

Effect of selective carious tissue removal on biomechanical behavior of class II bulk-fill dental composite restorations

OBJECTIVES

This study aimed to develop a method to induce carious lesions in the pulpal floor dentin of a class II cavity preparation, and to determine the effects of this carious lesion on the biomechanical behavior of the dental composite restoration.

METHODS

The pulpal floor dentin of class I cavities in sound third molars were demineralised with acetic acid for 35days followed by a 7-day exposure to pooled human saliva biofilm and demineralization was verified by micro-CT. Subsequently, the proximal walls were removed forming a class II cavity and the caries lesion was left intact or was completely removed prior to restoration with a bulk-fill dental composite (n=10). Cuspal deflection was assessed by strain-gauge and micro-CT imaging. The presence of enamel cracks was assessed by transillumination before and after restoration, and again after 1,200,000 cycles of mechanical fatigue in a chewing simulator. Finally, resistance to fracture by axial compressive loading and failure mode was determined. Data were analyzed by 2-way repeated measures ANOVA, Fisher's exact test, and t-test (α=0.05).

RESULTS

The presence of carious lesions had no significant effect upon cuspal deflection, formation of enamel cracks, and fracture strength of the dental composite restorations. The restorative procedure increased the number of enamel cracks, which was not affected by mechanical cycling.

SIGNIFICANCE

Maintaining carious lesions does not affect the biomechanical behavior of class II restorations performed with bulk-fill dental composite.

Teaching of posterior composites in dental schools in Japan - 30 years and beyond

OBJECTIVES

The teaching of posterior composites has been a major part of the curriculum in Japanese dental education for several decades. The aim of this paper was to investigate the current trends in the teaching of posterior composites to undergraduate dental students in Japan by comparing the results of surveys conducted for over 30 years.

METHODS

In late 2016-early 2017, a questionnaire seeking information on the teaching of posterior composites was distributed via e-mail to the persons responsible for teaching operative dentistry in 29 dental schools having undergraduate dental degree programs in Japan. The results obtained were compared to those from surveys conducted in 1986, 1997, and 2007.

RESULTS

All 29 schools that were sent the questionnaire completed the responses (response rate = 100%). All 29 schools reported teaching the placement of composite in occlusal and two-surface occluso-proximal cavities in both premolars and molars. Four schools reported not teaching the placement of three-surface occluso-proximal composites in premolars and five schools reported not teaching it for molars. Twenty-seven (93%) schools taught composite first as a part of the preclinical curriculum, whereas 15 (65%) schools did so in the survey of 2007. Variations were noted between schools in the teaching of, cavity design. In contrast, greater consistency was observed in the teaching of techniques for protecting exposed dentin and light-curing technologies.

CONCLUSIONS

It is hoped that measures intended to increase the clinical experience of restoring teeth with direct composite-resin for dental students in Japan will be effective, providing opportunity to bring dental education in Japan more into line with international norms.

Role of Proteolytic Enzyme Inhibitors on Carious and Eroded Dentin Associated With a Universal Bonding System

Objectives: The aim of this study was to evaluate the effect of proteolytic inhibitors on the bond strength of a universal adhesive system (etch-and-rinse mode) applied to artificial carious and eroded dentin. Methods: Ninety molars were prepared and randomly divided into three groups according to the substrate: N, no challenges; ACD, artificial carious dentin simulation and ERO, artificial erosion simulation with orange juice. All groups were redivided into three subgroups according to the dentin pretreatment: W, water; CHX, 2% digluconate chlorhexidine; and E-64 (trans-epoxysuccinyl-L-leucylamido-[4-guanidino] butane), 5 μM E-64 inhibitor. They constituted a total of nine groups (n=10): N-W, N-CHX, N-E64, ACD-W, ACD-CHX, ACD-E64, ERO-W, ERO-CHX, and ERO-E64. All specimens were restored with Adper Single Bond Universal/Filtek Z250. Beams (0.64 mm2) were obtained and subjected to the microtensile test (μTBS) in a universal testing machine at 0.5 mm/min. The failure mode of the interfaces was determined by optical microscopy (40× magnification). Data were statistically analyzed by three-way analysis of variance and Tukey tests (p&lt;0.05). Results: All individual factors (p&lt;0.0001) and the interaction between substrate and treatment (p=0.0011) and between substrate and time (p=0.0003) were statistically significant. The caries substrate contributed negatively to bond strength. Chlorhexidine reduced bond strength for normal and eroded conditions. Only the normal substrate was negatively affected by time despite the pretreatment. Conclusions: The universal bonding system appears to be a promising bonding strategy for the maintenance of bond strength to affected dentin. E-64 did not affect bonding to the dentin in contrast to the use of chlorhexidine, which, when associated with the universal system, did affect the microtensile bond strength for artificial carious dentin.

Radiographic diagnosis of proximal caries-influence of experience and gender of the dental staff

OBJECTIVES

The aim of this study was to examine the influence of experience and gender on the radiographic detection of proximal caries lesions and on therapeutic decisions.

MATERIALS AND METHODS

A survey of 220 examiners (students and employees at three universities and dentists in the field) was taken using a standardized written questionnaire concerning radiographic diagnosis and therapy planning. An expert opinion of four dentists was determined as radiographic reference. A mixed effect logistic regression model was used for statistical evaluation and the odds ratio and p values were calculated (α = 0.05).

RESULTS

Examiners with experience had an almost four times greater chance of a correct assessment, if proximal caries lesion was present or not, than examiners with low experience (OR 3.7 (95% CI 2.4-5.8)). No gender-specific differences were discovered (OR women vs. men 0.9 (95% CI 0.6-1.4)). There was a relationship between the severity of the burnout effect on the x-ray and false positive caries diagnosis. Overall, 43% of respondents would plan invasive treatment in the enamel on a patient at low risk of caries and 78% on a high-risk patient. The results showed that the more experienced practitioners would be more likely to postpone restorative therapy on proximal caries until the lesion reached a later stage.

CONCLUSIONS

The results of this study suggest that examiner's experience influences the radiographic diagnosis of proximal lesions. No gender-specific differences could be found.

CLINICAL RELEVANCE

Examiner's professional experience is an important factor when radiography is included for detection and treatment planning of proximal lesions.

Influence of Different Dentin Substrate (Caries-Affected, Caries-Infected, Sound) on Long-Term μTBS

Abstract The aim of this study was to evaluate the μTBS in different dentin substrates and water-storage periods. Twenty-four dentin blocks obtained from sound third molars were randomly divided into 3 groups: Sound dentin (Sd), Caries-affected dentin (Ca) and Caries-infected dentin (Ci). Dentin blocks from Ca and Ci groups were subjected to artificial caries development (S. mutans biofilm). The softest carious tissue was removed using spherical drills under visual inspection with Caries Detector solution (Ca group). It was considered as Ci (softer and deeply red stained dentin) and Ca (harder and slightly red stained dentin). The Adper Single Bond 2 adhesive system was applied and Z350 composite blocks were built in all groups. Teeth were stored in deionized water for 24 h at 37 ºC and sectioned into beams (1.0 mm2 section area). The beams from each tooth were randomly divided into three storages periods: 24 h, 6 months or 1 year. Specimens were submitted to µTBS using EZ test machine at a crosshead speed of 1.0 mm/min. Failure mode was examined by SEM. Data from µTBS were submitted to split plot two-way ANOVA and Tukey’s HSD tests (a=0.05). The µTBS (MPa) of Sd (41.2) was significantly higher than Ca (32.4) and Ci (27.2), regardless of storage. Ca and Ci after 6 months and 1 year, presented similar µTBS. Mixed and adhesive failures predominated in all groups. The highest µTBS values (48.1±9.1) were found for Sd at 24 h storage. Storage of specimens decreased the µTBS values for all conditions.

Synthetic phenolic antioxidants, including butylated hydroxytoluene (BHT), in resin-based dental sealants

Resin-based dental sealants (also referred to as pit-and-fissure sealants) have been studied for their contribution to bisphenol A (BPA) exposure in children. Nevertheless, little attention has been paid to the occurrence of other potentially toxic chemicals in dental sealants. In this study, the occurrence of six synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), 2,6-di-tert-butyl-4-(hydroxyethyl)phenol (BHT-OH), 3,5-di-tert-butyl-4-hydroxy-benzaldehyde (BHT-CHO), 2,6-di-tert-butylcyclohexa-2,5-diene-1,4-dione (BHT-Q), 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH) and 2-tert-butyl-4-methoxyphenol (BHA), was examined in 63 dental sealant products purchased from the U.S. market. BHT was found in all dental sealants at median and maximum concentrations of 56.8 and 1020µg/g, respectively. The metabolites of BHT and BHA were detected in 39-67% of samples, at concentration ranges of <LOQ to 242µg/g. BHT is likely used in sealants to inhibit oxidative reactions, remove free radicals, and inhibit potential polymerization, which would eventually prolong the shelf-life of the products. The estimated daily intake (EDI) of BHT, following sealant placement, based on a worst-case scenario (application on eight teeth at 8mg each tooth), was 930 and 6510ng/kg bw/d for adults and children, respectively. The EDI of BHT from dental sealants was several orders of magnitude lower than the current acceptable daily intake (ADI) proposed by the European Food Safety Authority (EFSA).

Effect of artificial saliva contamination on adhesion of dental restorative materials

The purpose of this study was to evaluate the effects of artificial saliva contamination on three restorative materials, namely, a glass ionomer cement (GIC), a resin-modified GIC (RMGIC), and a composite resin (CR), for which two different etching adhesive systems were used. Thus, three surface conditions were created on bovine teeth using artificial saliva: control, mild saliva contamination, and severe saliva contamination. The dentin bond strength for CR was significantly lower after artificial saliva contamination. There were, however, no significant differences among the three surface conditions in terms of the dentin and enamel bond strengths of GIC and RMGIC. Moreover, CR exhibited significantly greater microleakage after artificial saliva contamination, whereas no significant differences were found in GIC and RMGIC. The results showed that artificial saliva contamination did not affect the shear bond strengths of GIC and RMGIC or their degrees of microleakage.

Curing characteristics of flowable and sculptable bulk-fill composites

OBJECTIVES

The aim of this study was to determine and correlate the degree of conversion (DC) with Vickers hardness (VH) and translucency parameter (TP) with the depth of cure (DoC) of five bulk-fill composites.

MATERIALS AND METHODS

Six specimens per group, consisting of Tetric EvoCeram Bulk Fill ("TEC Bulk," Ivoclar Vivadent), SonicFill (Kerr), SDR Smart Dentin Replacement ("SDR," Dentsply), Xenius base ("Xenius," StickTech; commercialized as EverX Posterior, GC), Filtek Bulk Fill flowable ("Filtek Bulk," 3M ESPE), and Tetric EvoCeram ("TEC," control), were prepared for DC and VH: two 2-mm-thick layers, each light-cured for 10 s; one 4-mm bulk-fill, light-cured for 10 or 20 s; and one 6-mm bulk-fill, cured for 20 s. DC was measured using a Fourier-transform infrared spectrometer, VH using a Vickers hardness tester. DoC and TP were measured using an acetone-shaking test and a spectrophotometer, respectively. Data were analyzed using ANOVA and Pearson's correlation (α = 0.05).

RESULTS

DC and VH ranged between 40-70 % and 30-80 VHN, respectively. TEC Bulk, Xenius, and SonicFill, bulk-filled as 4-mm-thick specimens, showed bottom-to-top hardness ratios above 80 % after 20 s curing. A positive linear correlation was found for bottom DC and VH. An average DC ratio of 0.9 corresponded to a bottom-to-top VH ratio of 0.8.

CONCLUSIONS

Sculptable bulk-fills require 20 s, whereas 10 s curing time was sufficient for flowable bulk-fills using a high-intensity LED unit.

CLINICAL RELEVANCE

Clinicians should be aware that longer curing times may be required for sculptable than flowable bulk-fill composites in order to achieve optimal curing characteristics.

In vitro antibacterial activity of a novel resin-based pulp capping material containing the quaternary ammonium salt MAE-DB and Portland cement

Background

Vital pulp preservation in the treatment of deep caries is challenging due to bacterial infection. The objectives of this study were to synthesize a novel, light-cured composite material containing bioactive calcium-silicate (Portland cement, PC) and the antimicrobial quaternary ammonium salt monomer 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB) and to evaluate its effects on Streptococcus mutans growth in vitro.

Methods

The experimental material was prepared from a 2∶1 ratio of PC mixed with a resin of 2-hydroxyethylmethacrylate, bisphenol glycerolate dimethacrylate, and triethylene glycol dimethacrylate (4∶3∶1) containing 5 wt% MAE-DB. Cured resin containing 5% MAE-DB without PC served as the positive control material, and resin without MAE-DB or PC served as the negative control material. Mineral trioxide aggregate (MTA) and calcium hydroxide (Dycal) served as commercial controls. S. mutans biofilm formation on material surfaces and growth in the culture medium were tested according to colony-forming units (CFUs) and metabolic activity after 24 h incubation over freshly prepared samples or samples aged in water for 6 months. Biofilm formation was also assessed by Live/Dead staining and scanning electron microscopy.

Results

S. mutans biofilm formation on the experimental material was significantly inhibited, with CFU counts, metabolic activity, viability staining, and morphology similar to those of biofilms on the positive control material. None of the materials affected bacterial growth in solution. Contact-inhibition of biofilm formation was retained by the aged experimental material. Significant biofilm formation was observed on MTA and Dycal.

Conclusion

The synthesized material containing HEMA-BisGMA-TEGDMA resin with MAE-DB as the antimicrobial agent and PC to support mineralized tissue formation inhibited S. mutans biofilm formation even after aging in water for 6 months, but had no inhibitory effect on bacteria in solution. Therefore, this material shows promise as a pulp capping material for vital pulp preservation in the treatment of deep caries.

Evaluation of polymerization characteristics and penetration into enamel caries lesions of experimental infiltrants

OBJECTIVES

To evaluate the properties of experimental infiltrant blends by comparing them with the commercial infiltrant Icon(®) and penetration homogeneity into enamel caries lesions.

METHODS

Groups were set up as follows: G1 (TEGDMA 100%); G2 (TEGDMA 80%, Ethanol 20%); G3 (TEGDMA 80%, HEMA 20%); G4 (TEGDMA 75%, BisEMA 25%); G5 (TEGDMA 60%, BisEMA 20%, Ethanol 20%); G6 (TEGDMA 60%, BisEMA 20%, HEMA 20%); G7 (TEGDMA 75%, UDMA 25%); G8 (TEGDMA 60%, UDMA 20%, Ethanol 20%); G9 (TEGDMA 60%, UDMA 20%, HEMA 20%) and Icon(®). Ten specimens were comprised by each group for the following tests (n=10): degree of conversion (DC), elastic modulus (EM), Knoop hardness (KH), and softening ratio (SR). Infiltrant penetration was evaluated using confocal microscopy (CLSM). Data were subjected to two-way ANOVA and a Tukey's test (5%). Data comparing experimental materials and Icon(®) were analysed using ANOVA and Dunnett's test (5%).

RESULTS

The highest DC values were found in G1, G7, G8, and G9. The lowest DC values were found in G2, G4, G5, and G6. EM and KHN were significantly lower in HEMA and with ethanol addition for all blends, except for G9. There was no significant difference among the groups regarding SR, and it was not possible to take KHN readings of G2, G5, and G8 after storage. There was no significant difference among groups for infiltrant penetration into enamel lesions.

CONCLUSIONS

The addition of hydrophobic monomers and solvents into TEGDMA blends affected DC, EM, and KHN. UDMA added to TEGDMA resulted in an increase in DC, EM, and KHN. Overall, solvents added to monomer blends resulted in decreased properties. The addition of hydrophobic monomers and solvents into TEGDMA blends does not improve the penetration depth of the infiltrants.