Biomimetic Coatings in Implant Dentistry: A Quick Update

Biomimetic dental implants are regarded as one of the recent clinical advancements in implant surface modification. Coatings with varying thicknesses and roughness may affect the dental implant surface's chemical inertness, cell adhesion, and antibacterial characteristics. Different surface coatings and mechanical surface changes have been studied to improve osseointegration and decrease peri-implantitis. The surface medication increases surface energy, leading to enhanced cell proliferation and growth factors, and, consequently, to a rise in the osseointegration process. This review provides a comprehensive update on the numerous biomimetic coatings used to improve the surface characteristics of dental implants and their applications in two main categories: coating to improve osseointegration, including the hydroxyapatite layer and nanocomposites, growth factors (BMPs, PDGF, FGF), and extracellular matrix (collagen, elastin, fibronectin, chondroitin sulfate, hyaluronan, and other proteoglycans), and coatings for anti-bacterial performance, covering drug-coated dental implants (antibiotic, statin, and bisphosphonate), antimicrobial peptide coating (GL13K and human beta defensins), polysaccharide antibacterial coatings (natural chitosan and its coupling agents) and metal elements (silver, zinc, and copper).

Evaluation of Physical-Chemical Properties of Contemporary CAD/CAM Materials with Chromatic Transition "Multicolor"

The use of materials for computer-aided design/computer-aided manufacturing (CAD/CAM) has been rapidly increasing in daily practice. However, one of the main issues regarding modern CAD/CAM materials is their aging in the oral environment, which may lead to significant changes in their overall properties. The aim of this study was to compare the flexural strength, water sorption, cross-link density (softening ratio%), surface roughness, and SEM analysis of three modern CAD/CAM "multicolor" composites. Grandio (Grandio disc multicolor-VOCO GmbH, Cuxhaven, Germany), Shofu (Shofu Block HC-Shofu Inc., Kyoto, Japan), and Vita (Vita Enamic multiColor-Vita Zahnfabrik, Bad Sackingen, Germany) were tested in this study. They were prepared in stick-shaped specimens and submitted to different tests after several aging protocols, such as thermocycling and mechanical cycle loading challenge. Further disc-shaped specimens were also created and tested for water sorption, cross-link density, surface roughness, and SEM ultramorphology, before and after storage in an ethanol-based solution. For flexural strength and ultimate tensile strength, Grandio showed the greatest values both at baseline and after aging (p < 0.05). Grandio and Vita Enamic presented the highest modulus of elasticity and the lowest water sorption (p < 0.05). A significant reduction (p < 0.05) in microhardness after ethanol storage (softening ratio%) was observed especially in Shofu. Grandio had the lowest roughness parameters compared to the other tested CAD/CAM materials, while ethanol storage significantly increased the Ra and RSm values in Shofu (p < 0.05). Despite the comparable modulus of elasticity of Vita and Grandio, this latter showed greater flexural strength and ultimate tensile strength both at baseline and after aging. Hence, Grandio and Vita Enamic may be employed for the anterior teeth and for those restorations requiring load-bearing capacity. Conversely, aging seems to affect several properties of Shofu, so its use for permanent restorations should be well-pondered based on the clinical situation.

Association between Malnutrition and Dental Caries in Iraqi Kurdish Children

BACKGROUND

This paper aimed to study the association of serum Vitamin D level and Body Mass Index (BMI) as representatives of malnutrition at micro and macro levels, respectively, on dental caries.

METHOD AND PARTICIPANTS

A total of 333 randomly selected children aged 6-12 years in Sulaimani, Kurdistan, Iraq were examined for three variables of the Decayed Missed Filled Tooth (DMFT) index, BMI, and Vitamin D serum levels in a single-time cross-sectional snapshot.

RESULTS

The majority of the population studied (70%) were Vitamin D deficient. In the linear regression analysis, both Vitamin D and BMI had insignificant effects on DMFT, with p-values of 0.22 and 0.55, respectively. After the categorization of the data, the risk estimate between normal (≥20 ng/mL) and deficient (<20 ng/mL) Vitamin D groups with regards to the caries and caries-free categories was 1.97 (95% CI: 0.91-4.24). According to the mean and median of the DMFT, which were both 4, the sample is categorized into the low-caries group (DMFT < 4) and high-caries group (DMFT > 4). When these groups are compared to Vitamin D levels and taking 20 and 15 as thresholds, the odds ratios were 1.19 (CI: 0.74-1.92) and 1.88 (CI: 1.20-2.94), respectively. Regarding the BMI, a normal BMI increases the chances of having a lower caries index (OR = 1.83, CI: 1.10-3.03).

CONCLUSIONS

Our results show that having a serum Vitamin D level ≥15 ng/mL and having a normal BMI are associated with a lower caries index in children.

Culturing the Human Oral Microbiota, Updating Methodologies and Cultivation Techniques

Recent years have been marked by a paradigm shift in the study of the human microbiota, with a re-emergence of culture-dependent approaches. Numerous studies have been devoted to the human microbiota, while studies on the oral microbiota still remain limited. Indeed, various techniques described in the literature may enable an exhaustive study of the microbial composition of a complex ecosystem. In this article, we report different methodologies and culture media described in the literature that can be applied to study the oral microbiota by culture. We report on specific methodologies for targeted culture and specific culture techniques and selection methodologies for cultivating members of the three kingdoms of life commonly found in the human oral cavity, namely, eukaryota, bacteria and archaea. This bibliographic review aims to bring together the various techniques described in the literature, enabling a comprehensive study of the oral microbiota in order to demonstrate its involvement in oral health and diseases.

How to Intervene in the Caries Process in Children: A Joint ORCA and EFCD Expert Delphi Consensus Statement

This paper provides recommendations for dentists for the treatment of dental caries in children, with an emphasis on early childhood caries (ECC), primary teeth, and occlusal surfaces in permanent teeth. A consensus workshop followed by an e-Delphi consensus process was conducted with an expert panel nominated by the European Organization for Caries Research (ORCA) and European Federation of Conservative Dentistry (EFCD)/German Association of Conservative Dentistry (DGZ) boards. Based on 3 systematic reviews and a nonsystematic literature search, recommendations were developed. The caries decline has led to a more polarized disease distribution in children and adolescents along social gradients which should be taken into account when managing the caries process at all levels, such as the individual, the group, or a population. The control or reduction of caries activity is the basis for successful caries management. In children, caries management requires adequate daily oral hygiene and fluoride application via toothpaste, ensured by caregivers, and especially for ECC prevention an emphasis on sugar intake reduction is needed. These noninvasive interventions are also suitable to arrest or control initial or even cavitated dentine caries lesions in the absence of irreversible pulpitis. Fluoride varnish or silver diammine fluoride can be added as supplementary agents. In pits and fissures, composite resin materials can be used as preventive sealants and for defect-oriented minimally invasive restorations. In primary molars, preformed metal crowns are more successful than multisurface fillings, especially in caries-active patients. With persisting high caries activity, multiple lesions, and limited cooperation, caries control should consist of robust measures with high success rates, even including extraction in selected cases. This applies especially to treatments performed under general anesthesia.

Concordance study between regular face-to-face dental diagnosis and dental telediagnosis using fluorescence

Background

Teledentistry consultations are an effective way to increase access to care. Whether it be for a screening, referral or even an adapted treatment plan for a certain number of patients whose access to care is complicated, demonstrating the reliability of remote consultations is essential in allowing the technique to become generalised.

Aim

This study aimed to determine if teledentistry consultations using fluorescence are of the same quality as regular consultations in the diagnosis of caries.

Methods

Patients were seen in consultation in the dental care centre at the Montpellier University Hospital (France) and in the centre at Kyushu Dental University Hospital (Japan). The protocol was broken down into three parts: the regular consultation, the recording of videos with the Soprocare camera and the remote consultation. The regular consultation and the remote consultation were blinded and carried out by two different dentists. The recording of videos was carried out by a third dentist. The carious diagnosis was based on the International Caries Detection and Assessment System: a clinical rating system for the detection and assessment of caries.

Results

One hundred and ninety-five patients met the predefined inclusion criteria. Most patients had at least one surface at stage 3 or higher (73%) with a higher proportion amongst French patients (81% compared to 66%). However, they had good dental hygiene, given that dental hygiene was only deemed unsatisfactory for 10.8% (19% for French patients and 2% for Japanese patients). The odontogram (presence/absence of each tooth) seemed to be correctly identified during the remote consultation (reinterpretation). Out of the 195 patients, 168 (86.2%) were identified without error.

Conclusions

Teledentistry consultations can represent acceptable diagnostic performance with regard to the detection of dental caries. The Soprocare camera enables an early diagnosis of carious lesions with optimal efficiency. Several areas still need to be improved, however, so that the use of the camera during remote consultations is as coherent and effective as possible, especially with regard to the organisational aspects of remote consultations.

In Vitro Influence of Prophylaxis Cleaning on Enamel Remineralization with Casein Phosphopeptide-Amorphous Calcium Phosphate

Objectives

This randomized controlled in vitro 4-arm trial study aimed to study the remineralization potential of Recaldent™ and assess the effects of prophylaxis cleaning and MI Varnish^® on enhancing this remineralization potential.

Material and Methods

Sixty human teeth were randomly assigned into equal samples (A/B). Sample A was prophylactically cleaned, randomly divided into equal samples (1/2). Sample A1 received treatment with MI Varnish^® and Recaldent™ for 30 days. Sample A2 was treated similarly but without MI Varnish^®. Sample B did not receive prophylaxis cleaning and was divided into equal samples (1/2). Sample B1 was treated as A1 and sample B2 as A2. The teeth were examined for mineral composition at baseline, after the interventions (T1), and after prophylaxis cleaning (T2). Study outcomes were mineral content (% weight of carbon [C], phosphorus [P], calcium [Ca], oxygen [O], chlorine [Cl], sodium [Na] and silicon [Si]) and calcium-phosphorus ratio (Ca/P).

Results

All groups had similar mineral composition at baseline. At T1, sample B2 exhibited least P, Ca and Ca/P content. Samples A1 and B1 showed higher content of P and Ca, compared to B2 (A1 only exhibited higher Ca/P). Sample A2 exhibited lowest Cl and Na content. At T2, sample A1 exhibited lowest C, P, O and Si content (highest Ca/P). Sample A2 showed least Ca/P, and highest Na content.

Conclusions

Teeth treated by Recaldent™ proceeded by prophylaxis cleaning or MI Varnish^® showed remineralization, especially when receiving both interventions. This superior effect persisted even after a second cleaning. Further trials are necessary to provide conclusive evidence in humans.

Endoscopic System Based on Intraoral Camera and Image Processing

OBJECTIVE

In dentistry, dentists perform many treatments with a few visually magnified information. About deep area of root canals, it commonly relies on exploration carried out with the fingers of the dentist, because the root canal entrance is very small to be observed. In clinical practice, the intraoral camera and endoscopic systems are separate devices, and there are no sensors to capture both pictures of the whole tooth and those inside the root canal. Objective of this research is to combine the intraoral camera and endoscopic system facilitating to use clinical practice.

METHODS

We propose an endoscopic system based on the thin image fiber, SOPROLIFE intraoral camera as an image sensor, and a new adaptor to connect the two parts. We observed resolution charts with 50, 25, 10, and 5 line pairs (LP)/mm patterns. The acquired images are processed to both remove fixed-pattern noise using robust principal component analysis and enhance contrast.

RESULTS

The acquired images containing all LP/mm patterns were clear and showed higher contrast after processing. Visibility of the processed images is 1.7, 1.6, 2.2, and 1.9 times higher than that of the raw images for 50, 25, 10, and 5 LP/mm patterns, respectively.

CONCLUSION

Our fabricated endoscopic system based on the SOPROLIFE intraoral camera could observe 50, 25, 10, and 5 LP/mm patterns. After image processing, the noise was reduced, and high-contrast images were obtained.

SIGNIFICANCE

This system can be considered as a further step toward facilitating noninvasive and contactless systems in clinical practice.

Chemical & Nano-mechanical Study of Artificial Human Enamel Subsurface Lesions

White lesions represent an early phase of caries formation. 20 human sound premolars were subjected to pH cycling procedure to induce subsurface lesions (SLs) in vitro. In addition, 2 teeth with naturally developed white spot lesions (WSLs) were used as references. All specimens characterized by confocal Raman microscopy being used for the first time in examining white & subsurface lesions and providing a high resolution chemical and morphological map based on phosphate peak intensity alterations at 960 cm-1. Nanoindentation technique was used to measure Hardness (H) and Young's modulus (E) of enamel. Phosphate map of examined samples exhibited presence of intact surface layer (ISL) followed by severe depletion in (PO43-) peak in the area corresponding to the body of the lesion. In all examined groups, the mechanical properties of enamel were decreased in lesion area and found to be inversely related to penetration depth of indenter owing to enamel hierarchical structure. By combining the above two techniques, we linked mechanical properties of enamel to its chemical composition and ensured that the two methods are highly sensitive to detect small changes in enamel composition. Further work is required to bring these two excellent tools to clinical application to perceive carious lesions at an early stage of development.

MACVIA-LR (Fighting Chronic Diseases for Active and Healthy Ageing in Languedoc-Roussillon): A Success Story of the European Innovation Partnership on Active and Healthy Ageing

The Région Languedoc Roussillon is the umbrella organisation for an interconnected and integrated project on active and healthy ageing (AHA). It covers the 3 pillars of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA): (A) Prevention and health promotion, (B) Care and cure, (C) and (D) Active and independent living of elderly people. All sub-activities (poly-pharmacy, falls prevention initiative, prevention of frailty, chronic respiratory diseases, chronic diseases with multimorbidities, chronic infectious diseases, active and independent living and disability) have been included in MACVIA-LR which has a strong political commitment and involves all stakeholders (public, private, patients, policy makers) including CARSAT-LR and the Eurobiomed cluster. It is a Reference Site of the EIP on AHA. The framework of MACVIA-LR has the vision that the prevention and management of chronic diseases is essential for the promotion of AHA and for the reduction of handicap. The main objectives of MACVIA-LR are: (i) to develop innovative solutions for a network of Living labs in order to reduce avoidable hospitalisations and loss of autonomy while improving quality of life, (ii) to disseminate the innovation. The three years of MACVIA-LR activities are reported in this paper.

Laboratory Studies of Nonlinear Optical Signals for Caries Detection

Multiphoton confocal microscopy and nonlinear spectroscopy are used to investigate the caries process in dentin. Although dentin is a major calcified tissue of the teeth, its organic phase comprises type I collagen fibers. Caries drive dentin demineralization and collagen denaturation. Multiphoton microscopy is a powerful imaging technique: the biological materials are transparent to infrared frequencies and can be excited to penetration depths inaccessible to 1-photon confocal microscopy. The laser excitation greatly reduces photodamage to the sole focal region, and the signal-to-noise ratio is improved significantly. The method has been used to follow pathologic processes involving collagen fibrosis or collagen destruction based on their 2-photon excited fluorescence (2PEF) emission and second harmonic generation (SHG). Combining multiphoton imaging with nonlinear spectroscopy, we demonstrate that both 2PEF and SHG intensity of human dentin are strongly modified during the tooth caries process, and we show that the ratio between SHG and 2PEF signals is a reliable parameter to follow dental caries. The ratio of the SHG/2PEF signals measured by nonlinear optical spectroscopy provides valuable information on the caries process, specifically on the degradation of the organic matrix of dentin. The goal is to bring these nonlinear optical signals to clinical application for caries diagnosis.

A preliminary study of a new endodontic irrigation system: Clean Jet Endo

The purpose of the present study was to assess the irrigant penetration and cleaning ability of a new irrigation system, the Clean Jet Endo (Produits Dentaires SA, Switzerland) in comparison to conventional irrigation followed or not by sonic activation. Irrigant penetration was evaluated on resin blocks simulators by measuring the methylene blue absorbance thanks to a UV/visible spectrophotometer and cleaning ability was assessed in an ex vivo experiment according to the debris score in an artificial canal extension before and after the final irrigation protocol. A statistical analysis was carried out in order to highlight the significant differences between the irrigation techniques. Clean Jet Endo permitted to better eliminate the methylene blue into the simulated canals. A significant difference between the 2 techniques was observed in the middle third (p = 0.005) as well as in the apical third (p < 0.2). An additional microscope observation (16X) confirmed that Clean Jet Endo@ usage led to a better penetration of irrigant within the lateral canals of the simulators. Likewise, this irrigating system permitted to better eliminate the debris in the lateral groove than the other techniques. In conclusion, our findings implied the potential of this new irrigation system to enhance root canal debridement and disinfection.

Use of new minimum intervention dentistry technologies in caries management

Preservation of natural tooth structure requires early detection of the carious lesion and is associated with comprehensive patient dental care. Processes aiming to detect carious lesions in the initial stage with optimum efficiency employ a variety of technologies such as magnifying loupes, transillumination, light and laser fluorescence (QLF® and DIAGNOdent® ) and autofluorescence (Soprolife® and VistaCam®), electric current/impedance (CarieScan(®) ), tomographic imaging and image processing. Most fluorescent caries detection tools can discriminate between healthy and carious dental tissue, demonstrating different levels of sensitivity and specificity. Based on the fluorescence principle, an LED camera (Soprolife® ) was developed (Sopro-Acteon, La Ciotat, France) which combined magnification, fluorescence, picture acquisition and an innovative therapeutic concept called light-induced fluorescence evaluator for diagnosis and treatment (LIFEDT). This article is rounded off by a Soprolife® illustration about minimally or even non-invasive dental techniques, distinguishing those that preserve or reinforce the enamel and enamel-dentine structures without any preparation (MIT1- minimally invasive therapy 1) from those that require minimum preparation of the dental tissues (MIT2 - minimally invasive therapy 2) using several clinical cases as examples. MIT1 encompasses all the dental techniques aimed at disinfection, remineralizing, reversing and sealing the caries process and MIT2 involves a series of specific tools, including microburs, air abrasion devices, sonic and ultrasonic inserts and photo-activated disinfection to achieve minimal preparation of the tooth. With respect to minimally invasive treatment and prevention, the use of lasers is discussed. Furthermore, while most practices operate under a surgical model, Caries Management by Risk Assessment (CaMBRA) encourages a medical model of disease prevention and management to control the manifestation of the disease, or keep the oral environment in a state of balance between pathological and preventive factors. Early detection and diagnosis and prediction of lesion activity are of great interest and may change traditional operative procedures substantially. Fluorescence tools with high levels of magnification and observational capacity should guide clinicians towards a more preventive and minimally invasive treatment strategy.

Dental caries and enamelin haplotype

In the literature, the enamelin gene ENAM has been repeatedly designated as a possible candidate for caries susceptibility. Here, we checked whether ENAM variants could increase caries susceptibility. To this aim, we sequenced coding exons and exon-intron boundaries of ENAM in 250 children with a severe caries phenotype and in 149 caries-free patients from 9 French hospital groups. In total, 23 single-nucleotide polymorphisms (SNPs) were found, but none appeared to be responsible for a direct change of ENAM function. Six SNPs had a high minor allele frequency (MAF) and 6 others were identified for the first time. Statistical and evolutionary analyses showed that none of these SNPs was associated with caries susceptibility or caries protection when studied separately and challenged with environmental factors. However, haplotype interaction analysis showed that the presence, in a same variant, of 2 exonic SNPs (rs7671281 and rs3796704; MAF 0.12 and 0.10, respectively), both changing an amino acid in the protein region encoded by exon 10 (p.I648T and p.R763Q, respectively), increased caries susceptibility 2.66-fold independent of the environmental risk factors. These findings support ENAM as a gene candidate for caries susceptibility in the studied population.

Common SNPs of AmelogeninX (AMELX) and dental caries susceptibility

Genetic approaches have shown that several genes could modify caries susceptibility; AmelogeninX (AMELX) has been repeatedly designated. Here, we hypothesized that AMELX mutations resulting in discrete changes of enamel microstructure may be found in children with a severe caries phenotype. In parallel, possible AMELX mutations that could explain resistance to caries may be found in caries-free patients. In this study, coding exons of AMELX and exon-intron boundaries were sequenced in 399 individuals with extensive caries (250) or caries-free (149) individuals from nine French hospital groups. No mutation responsible for a direct change of amelogenin function was identified. Seven single-nucleotide polymorphisms (SNPs) were found, 3 presenting a high allele frequency, and 1 being detected for the first time. Three SNPs were located in coding regions, 2 of them being non-synonymous. Both evolutionary and statistical analyses showed that none of these SNPs was associated with caries susceptibility, suggesting that AMELX is not a gene candidate in our studied population.

Effect of Dual Cure Composite as Dentin Substitute on the Marginal Integrity of Class II Open-Sandwich Restorations

Dual-curing composites may present a good alternative to RMGIC in open-sandwich restorations and act as a dentin substitute. However, this study showed that RMGIC remains the best intermediate material when open-sandwich restorations are indicated.

Effect of dual cure composite as dentin substitute on marginal integrity of class II open-sandwich restorations

The current study compared the marginal adaptation of Class II open-sandwich restorations with a RMGIC versus a dual-cure composite as dentin substitute. Class II cavities were prepared on 50 extracted human third molars. The teeth were randomly assigned to two groups of 25 teeth to compare one dual cure composite (MultiCore Flow) with one resin-modified glass-ionomer cement (Fuji II LC) in open-sandwich restorations recovered with a light cure composite. The teeth were thermomechanocycled (2000 cycles, 5 degrees C to 55 degrees C; 100,000 cycles, 50 N/cm2). The specimens were then sealed with a 1 mm window around the cervical margin interface. Samples were immersed in a 50% w/v ammoniacal silver nitrate solution for two hours and exposed to a photo-developing solution for six hours. The specimens were sectioned longitudinally and silver penetration was directly measured using a light microscope. The results were expressed as a score from 0 to 3. The data were analyzed with a non-parametric Kruskal and Wallis test. The degree of leakage significantly increased with MultiCore Flow (median 2) compared to Fuji II LC (median 1). Resin-modified glassionomer cements remain the best intermediate material when open-sandwich restorations are indicated. A comparison of the degradation of these materials over time remains a topic to be investigated by future studies.

Minimally invasive dentistry using sonic and ultra-sonic devices in ultraconservative Class 2 restorations

AIM

Within the context of minimally invasive dentistry this article describes the sonic and ultrasonic cavity preparation techniques and assesses their advantages and disadvantages, clinical difficulties of their use, and offers a statement about these devices.

BACKGROUND

Ultra-conservative Class 2 restorative techniques require the use of devices such as sonic and the new ultrasonic preparation systems. These systems, featuring a series of sonic and new ultra-sonic inserts, allow for the fabrication of preventive preparations on proximal surfaces without injuring the adjacent proximal surface or damaging the marginal ridge.

REVIEW

An ultraconservative approach to the restoration of teeth with proximal caries that lack frank occlusal cavitation is facilitated by the use of slot-style cavity preparations created with sonic and ultrasonic instrumentation, and esthetic restorative materials.

SUMMARY

New restorative procedures appear suitable for use in ultraconservative restorative dentistry. More frequent use of these procedures by dental practitioners could prevent the traditional breakdown of the marginal ridge when preparing a Class 2 dental restoration. When cautiously used, these two ultraconservative devices provide alternative operative procedures to treat carious lesions without frank occlusal cavitation and to promote another aspect of preventive dentistry.

CLINICAL SIGNIFICANCE

New restorative procedures appear suitable for use in ultraconservative restorative dentistry. More frequent use of these procedures by dental practitioners could prevent the traditional breakdown of the marginal ridge when preparing a Class 2 dental restoration.

Influence of the number of sections on reliability of in vitro microleakage evaluations

PURPOSE

To test how the number of sections affects the maximum depth of tracer penetration.

MATERIALS AND METHODS

This study was simultaneously performed in three different centers. C-shaped Class V cavities were made on 60 human third molars. The cavities were located across the cementum-enamel junction. One restorative system was used: Scotchbond Multi-Purpose and Z100. After restoration, the samples were thermally cycled 3000 times, between 5 and 55 degrees C with a dwell time immersion of 10 seconds. Silver nitrate was used by two centers and basic fuchsin was used by the third. The teeth were longitudinally sectioned with a diamond saw: 5 sections per tooth provided 10 surfaces for evaluation. The penetration of the tracer was recorded on a scale from 0 to 3. The deepest leakage per restoration was identified for comparison with lesser measured values elsewhere in the tooth. The Spearman test was applied to evaluate the relationship between the reference and data from one, two and three sections (i.e. two, four and six measurements). The Kruskal-Wallis test was applied to compare the three centers.

RESULTS

Whatever the study center, the Spearman correlation coefficient (r(s)) increased as a function of the number of sections (S) up to three: Center 1 (1S, 0.47; 2S, 0.68; 3S, 1.0), Center 2 (1S, 0.60; 2S, 0.99; 3S, 0.99), Center 3 (S1, 0.40; 2S, 0.73; 3S, 1.0). No statistically significant difference was found between the three study centers.

In vitro assessment of polymerization procedures in Class II restorations: sealing, FTIR, and microhardness evaluations

PURPOSE

This study was undertaken to evaluate several polymerization and filling procedures (incremental, bulk, light-tip, soft-cured, plasma devices) in Class II restorations through (1) a sealing evaluation of restorations filled with Tetric Ceram (TC) and Bisfil 2B (B2B, self-cured composite used as a control), (2) a FTIR analysis measuring the variations of the degree of conversion in terms of area unit ratio of the relevant resin composites and (3) a microhardness test to corroborate the FTIR analysis.

MATERIALS AND METHODS

The length of the tracer penetration was measured from the gingival margin up to the cavity wall with an episcope on sectioned teeth. A ceramic mould, simulating a Class II, was filled according to the different groups and the samples were analyzed with a Bruker IFS 55 spectrometer on ultrathin sections (3 mu). The results were analyzed in terms of area unit ratio and total exposed energy. Under the same conditions, a microhardness test was run with a Frank Weihem machine.

RESULTS

The results of the sealing evaluation for light-tip, incremental and self-cured techniques did not differ. The plasma procedure failed in this evaluation as the bottom increment was not polymerized. The smallest area unit ratio (the best degree of conversion) was observed in 2 groups: one, the combination of the light-tip and soft process, and two, the self-cured resin composite (B2B). The distance at which the plasma procedure failed to cure the resin composite was between 3.5 and 4.5 mm. The microhardness test confirmed the FTIR analysis except for the group G2 (TC + light-tip). As also shown by FTIR analysis, no difference between the two relevant levels was observed with the hardness test.

CONCLUSION

The dentin marginal sealing efficiency of Tetric Ceram restorations was increased with the light-tip technique, but was not better than the self-cured resin composite (B2B). For Tetric Ceram, the combination of the light-tip and soft process leads to a higher degree of conversion than the other groups. There is no linear relationship between the degree of conversion, the microhardness and the total exposed energy. The combination of the soft polymerization and the light-tip device might be an alternative restorative technique to the current incremental technique.

In vivo diagnostic assessment of dentinal caries by junior and senior students using red acid dye

The aim of this study was firstly to determine and compare the ability of inexperienced junior dental students (Fourth-year) and senior students (Fifth-year) versus a dental school instructor to identify demineralized dentine with the aid of a caries-disclosing solution and secondly to evaluate an eventual improvement of the caries diagnosis accuracy of junior (Fourth-year) and senior (Fifth-year) dental students. Three successive stages were used to check the ability of the dental students to diagnose and excavate the de-mineralized dentine. This study pointed out that 96% of junior dental students versus a teacher failed to remove all of the demineralized dentine without the use of a caries detector at the first stage and 79% at the second stage in the same condition. 100% of senior students versus a teacher, also failed to diagnose dental caries without a caries detector, but only at the first stage. However, at the second stage, unlike the junior students, all of the senior students were able to remove all of the demineralized dentine. Without the use of a caries detector dye, the risks of the dental students leaving demineralized dentine are high. This technique may be particularly helpful for the fourth-year students who are performing their first restorative treatment.

Comparison of two implantation sites for testing intraosseous biocompatibility

The purpose of this study was to compare two implantation sites--the mandible and the femur of the rabbit--for testing in vivo intraosseous biocompatility. Twenty-two new Zealand rabbits were anesthetized, and the mandibular and femur bones were exposed. A hybrid glass ionomer cement or zinc oxide eugenol cement was loaded into silicone carriers and inserted into the two bones after drilling the two cortical plates. Eleven rabbits were killed 4 wk after implantation, and 11 rabbits were killed after 12 wk. The mandibles and femurs were prepared using standard histological procedures; tissue reactions were graded from none to severe. At 4 wk, no statistically significant difference was found between the two implantation sites. After 12 weeks, bone healing was statistically better in the mandible than in the femur. The mandible seems to be a better implantation site in the case of intraosseous implantation tests. The intraosseous biocompatibility of Vitremer was similar at 4 wk and superior at 12 wk to that of Super-EBA.

Comparison of the intraosseous biocompatibility of Vitremer and super EBA by implantation into the mandible of rabbits

OBJECTIVES

This study compared the intraosseous biocompatibility of Vitremer, a new hydrophilic glass-ionomer cement, to that of Super EBA.

STUDY DESIGN

Twenty-two New Zealand rabbits were anesthetized, the mandibular bone exposed, and two holes were drilled through the cortical plate. The materials were loaded into silicone carriers and inserted into the mandibles. Eleven rabbits were killed 4 weeks after implantation, 11 animals after 12 weeks. The mandibles were prepared with standard histologic procedures; the tissue reactions were graded from none to very severe.

RESULTS

At 4 weeks Vitremer implants showed very slight to slight reactions, and the Super EBA implants showed slight reactions and one moderate reaction with no significant difference between the two materials. At 12 weeks, bone healing had occurred, despite the persistence of some fibrous tissue interposition. The reactions were classified as none to very slight for Vitremer and very slight to slight for EBA. Statistical analysis showed better results for Vitremer at 12 weeks.

CONCLUSION

The intraosseous biocompatibility of Vitremer was similar at 4 weeks and superior at 12 weeks to that of Super EBA. Its other properties should be evaluated before considering its use in clinical practice.