Comparing accuracy in guided endodontics: dynamic real-time navigation, static guides, and manual approaches for access cavity preparation - an in vitro study using 3D printed teeth.

OBJECTIVES: To assess root canal localization accuracy using a dynamic approach, surgical guides and freehand technique in vitro. MATERIALS AND METHODS: Access cavities were prepared for 4 different 3D printed tooth types by 4 operators (n = 144). Deviations from the planning in angle and bur positioning were compared and operating time as well as tooth substance loss were evaluated (Kruskal-Wallis Test, ANOVA). Operating method, tooth type, and operator effects were analyzed (partial eta-squared statistic). RESULTS: Angle deviation varied significantly between the operating methods (p < .0001): freehand (9.53 ± 6.36°), dynamic (2.82 ± 1.8°) and static navigation (1.12 ± 0.85°). The highest effect size was calculated for operating method (ηP²=0.524), followed by tooth type (0.364), and operator (0.08). Regarding deviation of bur base and tip localization no significant difference was found between the methods. Operating method mainly influenced both parameters (ηP²=0.471, 0.379) with minor effects of tooth type (0.157) and operator. Freehand technique caused most substance loss (p < .001), dynamic navigation least (p < .0001). Operating time was the shortest for freehand followed by static and dynamic navigation. CONCLUSIONS: Guided endodontic access may aid in precise root canal localization and save tooth structure. CLINICAL RELEVANCE: Although guided endodontic access preparation may require more time compared to the freehand technique, the guided navigation is more accurate and saves tooth structure.

Does dynamic navigation system preserve more dentine? - A systematic review.

OBJECTIVE: This systematic review aims to comparatively analyse the amount of dentin removal by free hand and static guided endodontics with dynamic navigation system (DNS) in endodontic access cavity preparation. METHODS: The systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Based on the structured PICO framework of "Comparative evaluation of dynamic navigation system (I) to freehand (C) and static guided endodontics (C) in endodontic access cavity preparation on the preservation of tooth structure (O) when assessed on permanent human teeth (P)", the keywords were formulated and the articles were retrieved from three databases namely PubMed, Scopus and Embase, based on the keywords from the time of inception of DNS till June 2023. The risk of bias assessment was done using a modified Joanne Briggs Institute checklist, which evaluated domains such as randomisation, sample size, image acquisition using CBCT, angulation, accuracy and time taken. As the data was heterogenous, a quantitative meta-analysis was not performed. RESULTS: Initially, 174 articles were retrieved from the three databases, 30 duplicates were removed, after title check 108 articles were excluded and following abstract check only 10 articles qualified for full text analysis. On reviewing the 10 full text articles, 5 articles were excluded and the remaining 5 articles were subjected to the risk of bias analysis which showed that 2 articles displayed low risk of bias and three articles showed high risk of bias. The RoB analysis revealed that only 2 studies evaluated the preservation of dentin in terms of accuracy, angulation and time taken proving the increased precision with minimal loss of tooth structure using DNS. In both the studies, DNS proved to be superior to free hand technique in terms of precision, accuracy and efficiency in locating the canals during access cavity preparation with maximal preservation of tooth structure. CONCLUSION: With the minimal literature evidences, the present systematic review highlights maximal preservation of dentin using DNS. However, further invitro and invivo studies comparing the free hand, static guided endodontics to DNS must be carried out for its translation into clinical practice. CLINICAL SIGNIFICANCE: Dynamic navigation system provides maximal preservation of dentin during access cavity preparation.

Shear bond strengths of bur or Er:YAG laser prepared dentine to composite resin with or without low-level laser conditioning: an in vitro study.

This study aims to compare the different modes of cavity preparation while evaluating the effect of low-level laser therapy (LLLT) on dentine before bonding in terms of shear bond strength between composite resin and dentine. Fifty human molar teeth were mounted on acrylic blocks and dentine specimen were prepared after which they were randomized into four equal groups. Cavity preparation mode differed in respective groups. After etching, bonding; composite resin was placed and polymerized on the prepared dentine surfaces. The specimens were kept in an environment simulating oral cavity and then shear tested in a universal testing machine. The failure surfaces of the specimen teeth were subjected to SEM micrographic evaluation. The cavity prepared with diamond abrasive points had a higher shearing load at failure that was statistically significantly different from the ones prepared with laser. That with diamond abrasive points followed by LLLT of the cavity surface with Nd:YAG laser had a higher bond strength than the ones prepared with just Er:YAG laser and there was no statistically significant difference between these and the ones prepared with diamond abrasive points alone. SEM analysis of the failure mode in bur-cut dentine showed the presence of a hybrid layer at the interface. Surface conditioning of the same with Nd:YAG laser before etching suggested a recrystallisation of dentine due to the heat produced. Cavity preparation with Er:YAG laser leads to reduced shear bond strength to adhesive restorative materials when compared with that using burs and high-speed handpiece.

Design of an interactive system for access cavity assessment: A novel feedback tool for preclinical endodontics.

INTRODUCTION: A software program was developed to provide visual, guided feedback to students for access cavity preparations in preclinical learning. The specific aim of the study was to investigate students' overall experiences with the new learning method and compare their experiences with traditional teaching. MATERIALS AND METHODS: A workflow based on freely available software was designed to interactively register three-dimensional models of molars with access cavities, and to metrically compare these to instructor-prepared standard cavities. Third-year students practicing molar endodontics access cavity preparation in the preclinical course were then surveyed. A total of 44/79 students completed self-administered questionnaires prior and after the use of the feedback software to gauge their learning experience. RESULTS: The results of the post-training questionnaire illustrated that all surveyed students agreed/strongly agreed that the software assisted their learning in access cavity preparation. In addition, 86 and 89%, respectively, of students agreed that the use of the software improved their skills of access cavity preparation and felt more confident about their access cavity preparation skills after using the software package, 3D Dental Align. DISCUSSION: The presented software solution permitted setting and comparing access cavity preparations by students against a standard access prepared by an instructor. The process of data acquisition and registration was fast and straightforward. Student feedback was very positive and suggested the integration of this type of experiential learning into the preclinical curriculum. CONCLUSION: This feasibility study demonstrated the utility of the new technology to assist dental students' access cavity preparation learning.

Present status and future directions - Minimal endodontic access cavities.

In the last decades, the move of medicine towards minimally invasive treatments is notorious and scientifically grounded. As dentistry naturally follows in its footsteps, minimal access preparation have also becume a trend topic in the endodontic field. This procedure aims to maximize preservation of dentine tissue backed up by the idea that this is an effective way to reduce the incidence of post-treatment tooth fracture. However, with the assessment of the body of evidence on this topic, it is possible to observe some key points (a) the demand for nomenclature standardization, (b) the requirement of specific tools such as ultra-flexible instruments, visual magnification, superior illumination, and three-dimensional imaging technology, (c) minimally invasive treatment does not seem to affect orifice location and mechanical preparation when using adequate armamentarium, but it (d) may impair adequate canal cleaning, disinfection and filling procedures, and also (e) it displays contradictory results regarding the ability to increase the tooth strengthen compared to the traditional access cavity. In spite of that, it is undeniable that methodological flaws of some benchtop studies using extracted teeth may be responsible for the conflicting data, thus triggering the need for more sophisticated devices/facilities and specifically designed research in an attempt to make clear the role of the access size/design on long-term teeth survival. Moreover, it is inevitable that a clinical approach such as minimal endodontic access cavities that demands complex tools and skilled and experienced operators bring to the fore doubts on its educational impact mainly when confronted with the conflicting scientific output, ultimately provoking a cost-benefit analysis of its implementation as a routine technique. In addition, this review discusses the ongoing scientific and clinical status of minimally invasive access cavities aiming to input an in-depth and unbiased view over the rationale behind them, uncovering not only the related conceptual and scientific flaws but also outlining future directions for research and clinical practices. The conclusions attempt to skip from passionate disputes highlighting the current body of evidence as weak and incomplete to guide decision making, demanding the development of a close-to-in situ laboratory model or a large and well-controlled clinical trial to solve this matter.

Does selective caries removal in combination with antimicrobial photodynamic therapy affect the clinical performance of adhesive restorations of primary or permanent teeth? A systematic review with meta-analysis.

Antimicrobial photodynamic therapy (aPDT) is an adjunct to a selective caries removal (SCR) technique for deep caries lesion treatment. The knowledge about chemical and structural changes affecting the remaining dentin surface after the use of this therapy is still unknown. OBJECTIVE: to answer the following question: Does the SCR technique in combination with aPDT affect the clinical performance of adhesive restorations in deep carious lesions of primary or permanent teeth? STUDY DESIGN: a systematic review was conducted. Five databases, supplemented by trial registers, google scholar, manual search, personal communications, and grey literature were investigated. Randomized clinical trials were included. Two independent reviewers selected the studies, extracted qualitatively the data, and evaluated the risk of bias (using Cochrane Collaboration's tool and Robot Reviewer program). The certainty of the evidence was accessed based on The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. A meta-analysis of comparable data was performed with RevMan software 5.3. RESULTS: A total of 39 articles and 3 studies were found. The final selection included 3 articles with a total of 82 participants. No studies were found on permanent teeth. The studies presented low risk of bias. Considering the treatment in the experimental (SCR + aPDT) or control groups (SCR), no difference on clinical performance of adhesive restorations in deep caries of primary teeth was observed after 6 months (p = 0.78; CI -0.01 (-0.09, 0.07)) or 12 months (p =0.75; CI -0.02 (-0.12, 0.08)). All outcomes presented moderate certainty of evidence mainly due to the small sample size that downgrade the GRADE scores. CONCLUSIONS: based on moderate certainty of the evidence, the clinical use of aPDT as an adjuvant of SCR has potential indication for treatment in deep caries of primary teeth. However, studies with more follow up and on permanent teeth are missing with the necessity for further research.

The Application of a Case-Based Social Media-Assisted Teaching Method in Cariology Education：Comparative Study.

BACKGROUND: Current cariology education based on the traditional teaching method faces a lot of challenges. Meanwhile, the COVID-19 pandemic caused an unprecedented disruption in medical education and health care systems worldwide. Innovation in the teaching mode of cariology education is required to change the situation. OBJECTIVE: The goal of the research was to evaluate the application effects of a case-based social media-assisted teaching method in cariology education. METHODS: Dental students of class 2019 were enrolled into the experimental group, while students of class 2018 served as control. A case-based social media-assisted teaching method was used in the experimental group, which included preclass activity via social media, additional discussion and practice process record in class, and questions and answers on the platform after class. The traditional teaching method, which consisted of conventional preparation before class, traditional lectures and demonstrations followed by students practice in class, and questions and answers step after class, was used in the control group. The teaching materials were the same in both groups. At the end of the program, students from both groups took cavity preparation skill evaluation tests. Questionnaires were tested on the case-based social media-assisted teaching group students anonymously. All data were analyzed using SPSS statistical software (version 22.0, IBM Corp). RESULTS: The mean student cavity preparation skill evaluation scores was 82.51 (SD 6.82) in the experimental group and 77.19 (SD 5.98) in the control group (P<.05). The questionnaire response rate was 100%. Of those, 94.3% (100/106) of the students recommended the case-based social media-assisted teaching method in cariology education. The majority of the participants agreed that it helped them memorize the theoretical knowledge of cariology, facilitated in-depth discussion, improved their enthusiasm and initiative in learning, and enhanced the relationship between teachers and students (104/106, 98.1%). They also recognized that the classroom atmosphere was active (94/106, 88.7%). CONCLUSIONS: The case-based social media-assisted teaching method was beneficial in terms of learning, as demonstrated by the statistically significant improvement of the cavity preparation skill evaluation scores and satisfaction from attending students. This method could be used to supplement the teaching of cariology.

Influence of selective caries excavation on marginal penetration of class II composite restorations in vitro.

Selective caries excavation may support pulp preservation. This in vitro study investigated the influence of selective removal of demineralized dentin on marginal integrity of composite restorations as determined by dye penetration. Dentinal caries-like lesions were produced in the approximal surfaces of 40 extracted human molars (ethylenediaminetetraacetate, 0.5 M, 96 h). The following test procedures were established: complete excavation, selective excavation, and caries-free control. Two class II cavities with enamel at the cervical margins were prepared per tooth and demineralization volume was determined by micro-computed tomography for the purpose of a stratified distribution to receive complete excavation or selective excavation. After complete or selective excavation (30 cavities each), adhesive composite restorations were placed. Cavities without demineralized dentin (20 cavities) served as control. The marginal integrity of restorations was evaluated by dye penetration with and without thermocycling or mechanical loading. Results were analyzed by non-parametrical statistical tests (Mann-Whitney U Test) with an α = 0.05 level of significance. Dye penetration did not differ significantly among completely excavated, selectively excavated, or undemineralized teeth, but was increased by thermocycling and mechanical loading in all experimental groups. Selective caries removal did not increase marginal penetration in class II restorations. The presence of remaining demineralized dentin surrounded by sound dentin did not impair marginal integrity of restorations with margins placed in sound enamel.

Influence of 38% silver diamine fluoride application on bond stability to enamel and dentin using universal adhesives in self-etch mode.

In order to evaluate the influence of 38% silver diamine fluoride (SDF) application on enamel and dentin bond stability of universal adhesives in self-etch mode, a 38% SDF and three universal adhesives were used in this study. Initial shear bond strength (ISBS), fatigue bond strength (FBS), and shear bond strength of survivors (SBSS) to enamel and dentin of universal adhesives in self-etch mode, with and without SDF application, were determined. SDF was applied to the polished enamel or dentin surface for 1 min, water-rinsed and air-dried for comparison with controls. The universal adhesives were applied to the prepared samples and composite resin was bonded using a mold-enclosed method. Enamel bond stability of universal adhesives with SDF (ISBS: 14.7-20.4 MPa; FBS: 5.5-7.4 MPa and SBSS: 14.4-21.5 MPa) was significantly weaker than those without SDF (ISBS: 28.0-29.2 MPa; FBS: 12.1-15.6 MPa and SBSS: 28.4-34.4 MPa). Dentin bond stability with SDF (ISBS: 14.8-20.9 MPa; FBS: 7.1-8.2 MPa and SBSS: 17.3-21.8 MPa) was also significantly weaker than without SDF (ISBS: 19.3-36.1 MPa; FBS: 11.0-13.7 MPa and SBSS: 22.2-34.6 MPa). The results suggest that SDF application on enamel and dentin reduces the bond stability of universal adhesives in self-etch mode.

Current status on minimal access cavity preparations: a critical analysis and a proposal for a universal nomenclature.

In the last decade, several access cavity designs involveing minimal removal of tooth tissue have been described for gaining entry to pulp chambers during root canal treatment. The premise behind this concept assumes that maximum preservation of as much of the pulp chamber roof as possible during access preparation would maintain the fracture resistance of teeth following root canal treatment. However, the smaller the access cavity, the more difficult it may be to visualize and debride the pulp chamber as well as locate, shape, clean and fill the canals. At the same time, a small access cavity may increase the risk of iatrogenic complications as a result of poor visibility, which may have an impact on treatment outcome. This study aimed to critically analyse the literature on minimal access cavity preparations, propose new nomenclature based on self-explanatory abbreviations and highlight the areas in which more research is required. The search was conducted without restrictions using specifics terms and descriptors in four databases. A complementary screening of the references within the selected studies, as well as a manual search in the highest impact journals in endodontics, namely International Endodontic Journal and Journal of Endodontics, was also performed. The initial search retrieved 1831 publications. The titles and abstracts of these papers were reviewed, and the full text of 94 studies was assessed. Finally, a total of 28 studies were identified as evaluating the influence of minimally invasive access cavity designs on the fracture resistance of teeth and on the different stages of root canal treatment (orifice location, canal shaping, canal cleaning, canal filling and retreatment). Overall, the studies had major methodological drawbacks and reported inadequate and/or inconclusive results on the utility of minimally invasive access preparations. Furthermore, they offered limited scientific evidence to support the use of minimally invasive access cavities to improve the outcome of root canal treatment and retreatment; they also provided little evidence that they preserved the fracture resistance of root filled teeth to a greater extent than traditional access cavity preparations. It was concluded that at present, there is a lack of supporting evidence for the introduction of minimally invasive access cavity preparation into routine clinical practice and/or training of undergraduate and postgraduate students.

Does Er,Cr:YSGG reduce the microleakage of restorations when used for cavity preparation? A systematic review and meta-analysis.

BACKGROUND: As the member of erbium laser family, Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) has obtained the approval for caries removal and cavity preparation by Food and Drug Administration (FDA). However, there is still controversy over the beneficial effects of Er,Cr:YSGG preparations on microleakage. The present study is the first systematic review and meta-analysis to compare the microleakage of cavities prepared by Er,Cr:YSGG lasers with that by traditional burs. In addition, the effect of acid etching on the adhesive potential of self-etch and etch-and-rinse adhesives was assessed after laser preparation. METHODS: An electronic search was performed in Pubmed, EBSCO, Embase, and the Cochrane Controlled Register of Trials (CENTRAL). RESULTS: Totally, 357 articles were identified. Finally, 13 met the inclusion criteria, of which 11 were selected for meta-analysis. All the included studies exhibited a moderate risk of bias. Based on the meta-analysis, no significant difference was observed between the Er,Cr:YSGG and traditional bur groups in terms of the incidence of microleakage. Self-etch adhesives, in combination with prior acid etching, showed less microleakage than those without acid etching in the laser-prepared cavities. CONCLUSIONS: Current studies do not support the beneficial effects of Er,Cr:YSGG preparations on microleakage. Additional acid etching with self-etching adhesives is recommended after Er,Cr:YSGG preparations. Further high-quality studies are needed to draw a convincing conclusion in the future.

Antibacterial effect of diode laser on different cariogenic bacteria: An In-vitro study.

AIMS: The authors have used an in vitro model to appraise the antimicrobial efficacy of diode lasers with two different power outputs on Streptococcus mutans (SM), Lactobacillus casei (LC), and Actinomyces naeslundii (AN). METHODS AND MATERIALS: The coronal dentin of thirty human mandibular third molars was prepared with four cylindrical cavities left in contact with SM, LC, and AN for 72 h to facilitate bacterial penetration. Diode laser (810 nm for 30 s in two cycles) with 1.5 W (group I), 1 W (group II), and 2% chlorhexidine gluconate solution for 60 s (group III) was applied on three cavities and the fourth cavity was not subjected to any treatment (control). Similar amounts of dentin debris were collected from the cavity into sterile tubes. The bacterial count was determined by serial dilution and plate count method. Percentage of killing was calculated for comparative analysis. RESULTS: The percentage of SM killed after exposure was 73.68 ± 23.37, 51.75 ± 25.45, and 26.78 ± 21.8 in three groups, respectively, (P = 0.002; Kruskal-Wallis) with no significant difference between group I and group II (P = 0.089; Mann-Whitney). The percentage of AN killed after exposure was 37.77 ± 49.52, 22 ± 19.48, and 56.86 ± 23.93 in three groups, respectively, (P = 0.013; Kruskal-Wallis) with significant difference between group II and group III (P = 0.002; Mann-Whitney). The percentage of LC killed after exposure was 51.32 ± 39.07, 36.65 ± 38.48, and 75.41 ± 22.6 in three groups, respectively (P = 0.091; Kruskal-Wallis). CONCLUSIONS: Diode lasers exerted antibacterial effect of varying levels against all the three cariogenic bacteria. Although they are recommended as a supplementary antibacterial surface pretreatment technique for efficient removal of cariogenic bacteria, further clinical studies are required to confirm the in vitro findings.

Effect of preheated bulk-fill composite temperature on intrapulpal temperature increase in vitro.

OBJECTIVES: The aim of study is measurement of in vitro intrapulpal temperature increase when placing room temperature or preheated (54°C and 60°C) bulk-fill composite. MATERIALS AND METHODS: Extracted human lower third molars were selected and class II (MOD) cavities in each tooth were prepared, resulting in a remaining dentin thickness of 1 mm. A K-type thermocouple was placed inside the pulp chamber. Teeth were placed in a 37°C bath, which simulated human body temperature. Teeth were restored with a bulk-fill composite that was stored at room temperature and preheated at 54°C and 60°C. Data were subjected to two-factor mixed-design analysis of variance using a general linear model procedure for repeated measurements. RESULTS: Stage, composite temperature, and stage-composite temperature interaction significantly affected the intrapulpal temperature values (P < .001). CONCLUSIONS: Preheating does not represent significant problems in terms of intrapulpal temperature increase. Even Though the preheating process results in an increase in intrapulpal temperature, this temperature increase is not the critical factor that causes harm to the pulp. CLINICAL SIGNIFICANCE: Preheating can improve material features. Benefits of improved material features are desirable to practitioners. Temperature increase is not the critical factor that harms to the pulp even if the preheating process can result with an increase in intrapulpal temperature.

Assessment of Microleakage Using Dye Penetration Method in Primary Teeth Restored with Tooth-colored Materials: An In Vitro Study.

AIM: The present study aimed to assess the microleakage in primary teeth restored with tooth-colored materials using the dye penetration method. MATERIALS AND METHODS: A total of 60 healthy primary molar teeth were included in this study and standardized class II mesio-occlusal cavities were prepared on the samples. Consequently, these teeth were randomly divided into three experimental groups (n = 20 each group) such as group I: nano-filled resin-modified glass-ionomer, group II: nanocomposite resin, and group III: Cention N. After completing all the restorations, the restored teeth were subjected to 100 cycles of thermocycling. Next, all the surfaces of the tooth, except the restoration and a 1-mm zone adjacent to the restoration's margins, were covered with two coats of nail varnish. The coated teeth were then submerged in a 0.5% basic fuchsin dye solution. The teeth were then sectioned along the center of each restoration mesiodistally. Each part was visualized under a stereomicroscope at ×40 magnifications to assess microleakage. RESULTS: Out of all the included restorative materials, the least microleakage was demonstrated by teeth restored by the nano-filled resin-modified glass-ionomer (RMGI) group (1.05 ± 0.21) followed by the Cention N group (1.84 ± 0.14) and the nanocomposite resin group (3.10 ± 0.03). A statistical method involving the analysis of variance revealed a statistically significant difference among the different restorative materials. Multiple comparisons among the restorative materials showed a statistically significant difference between groups I and II and groups II and III restorative materials (p < 0.05). The dye penetration score 1 was more [11(55%)] for the nano-filled RMGI group, score 3 was more [12(60%)] for the nanocomposite resin group, and score 2 was more [9(45%)] for the Cention N group. CONCLUSION: The present study showed significantly less microleakage associated with the nano-filled resin-modified glass ionomer group than nanocomposite resin and Cention N groups. CLINICAL SIGNIFICANCE: Since many years, dentists have encountered a challenging problem with cervical lesions. Thus, an interdisciplinary treatment approach is the appropriate option in the management of carious teeth that involve gingival recession and cervical extension.

Microleakage Evaluation of an Alkasite Restorative Material: An In Vitro Dye Penetration Study.

AIM: The aim of the present in vitro study was to comparatively evaluate the microleakage in three different esthetic restorative materials in class I cavities using the dye penetration technique. MATERIALS AND METHODS: Class I cavities were prepared on 24 human maxillary premolar teeth. The teeth were randomly divided into four groups of six samples each. Group I: Cention-N without adhesive (Ivoclar Vivadent, India), group II: Cention with adhesive (Ivoclar Vivadent, India), group III: type IX glass ionomer cement (Fuji), group IV: posterior composite (3M ESPE). The specimens were polished, subjected to thermocycling, and suspended in methylene blue dye for 24 hours. The teeth were sectioned longitudinally and the extent of microleakage was evaluated using the stereomicroscope. RESULTS: The results were subjected to statistical analysis using the Pearson's Chi-square test and the interobserver variability was assessed by the Kappa test for interobserver variability. The analysis showed statistically significant results among the groups. Although, Cention N with adhesive showed the least microleakage followed by Cention N without adhesive. CONCLUSION: All the materials tested were unable to completely eliminate microleakage in class I cavities. However, the newer alkasite material Cention N proved to have the least microleakage among all groups. CLINICAL SIGNIFICANCE: According to the present study, Cention N, a newer alkasite restorative material, demonstrated promising results with the least microleakage in comparison with posterior resin composites and glass ionomer cements. How to cite this article: Kini A, Shetty S, Bhat R, et al. Microleakage Evaluation of an Alkasite Restorative Material: An In Vitro Dye Penetration Study. J Contemp Dent Pract 2019;20(11):1315-1318.

Expression and localization of CRAMP in rat tooth germ and during reparative dentin formation.

OBJECTIVES: Cathelicidin-related antimicrobial peptide (CRAMP) is an antimicrobial peptide in mice and rats homologous to LL-37 in humans. In addition to its antibacterial activity, CRAMP has various physiological functions by binding to formyl peptide receptor 2 (FPR2). However, the role of these peptides in teeth is unknown. Therefore, we investigated the role of CRAMP and FPR2 in tooth development, reparative dentin formation, and defense response. MATERIAL AND METHODS: First, we examined the localization of CRAMP and FPR2 during tooth development by immunohistochemical analysis. Next, we investigated the localization of CRAMP, FPR2, and CD68-positive macrophages by immunohistochemical analysis during pulp inflammation and reparative dentin formation after cavity preparation. Finally, we analyzed the effect of lipopolysaccharide (LPS) on the expression of CRAMP and FPR2 in dental pulp cells by real-time reverse transcription PCR. RESULTS: At the late bell stage in tooth development, CRAMP was detected in odontoblasts, and FPR2 was observed in the sub-odontoblastic layer. In mature teeth, CRAMP was not detected, but FPR2 continued to be localized in the sub-odontoblastic layer. After cavity preparation, CRAMP-positive cells and macrophages were found in dental pulp tissues below the cavity at an early stage of repair. At subsequent stages of reparative dentin formation, CRAMP was observed in odontoblast-like cells that contacted reparative dentin. FPR2 immunoreactivity was also detected in odontoblast-like cells and neighboring cells. LPS stimulated the expression of CRAMP mRNA in dental pulp cells in vitro. CONCLUSIONS: Localization of CRAMP and its receptor FPR2-positive cells were observed during physiological and reparative dentin formation. CLINICAL RELEVANCE: CRAMP/LL-37 has a possibility that induce reparative dentin formation.

Investigating an errorless learning approach for developing dental operative technique skills: A pilot study.

INTRODUCTION: Explicit instruction (conscious knowledge/rules) is generally used for learning dental operative skills; however, recent work has demonstrated advantages of learning skills implicitly with minimal accrual of conscious knowledge and reduced attentional demands. Therefore, this study examined the effects of learning handpiece manipulation skills explicitly (errorful) and implicitly (errorless: limited error detection/correction) under conditions of increased attentional demands (ie multitasking and additional instructions). MATERIALS AND METHODS: Non-dental university students were randomly assigned to errorless (n = 11) or errorful (n = 8) groups. They used pencil lead instead of a bur, with errorless learners shading shapes from simple (small circle) to complex (cross), while errorful learners shaded the shapes in reverse. During testing, they completed simulated cavities in baseline, additional instructions and multitask conditions. Learning performance was calculated as per cent of the shape shaded successfully. Test performance was computed as error in cavity length/depth and was compared with dental students who had completed their operative technique course (n = 14). RESULTS: Errorless learners were more accurate than errorful learners especially when shading difficult shapes (P = 0.042). With additional instructions, errorless and errorful learners did not differ in cavity depth (P = 0.057) or length (P = 0.540). When multitasking, errorless learners prepared the cavity length (P = 0.048) but not depth (P = 0.920) more accurately than errorful learners. Overall, performance of errorless learners was comparable to dental students. CONCLUSIONS: These preliminary findings suggest handpiece skills can be acquired implicitly via errorless learning, and it is less attentionally demanding than errorful learning, as evident by maintenance of preparation performance when processing additional relevant instructions and multitasking.

Prognosis of Indirect Composite Resin Cuspal Coverage on Endodontically Treated Premolars and Molars: An In Vivo Prospective Study.

PURPOSE: This prospective clinical study evaluated the success rate of indirect composite resin cuspal coverage on endodontically treated molars and premolars and the survival rate of the restored teeth. MATERIALS AND METHODS: One hundred fifty endodontically treated teeth were restored with total resin cuspal coverage and randomly selected for the study. Patients were recalled after 2 to 5 years for clinical evaluation. Data were subjected to standard tests of statistical correlations using Spearman test. RESULTS: Out of the 150 teeth, 84 were molars and 66 were premolars. Of these teeth, 58.7% had mesio-occlusal-distal (MOD) cavities, 20.7% had mesio-occlusal (MO), and 20.7% had occlusal-distal (OD). A build-up procedure was performed in 51.3% of the teeth, and buccal veneer composite resins were placed at the margins of 96.7% of the teeth. Out of the 150 teeth, 30 (20%) presented margin discoloration, 3 teeth (2%) had restoration reparable fractures, 2 teeth (1.3%) had restoration irreparable fractures, and 1 tooth (0.7%) exhibited secondary recurrent caries. The opposing arch that occluded with the treated teeth presented 58% natural teeth (no restoration material), 26.7% ceramic crowns, and 15.3% implant-supported ceramic crowns. Statistically significant differences (p = 0.018) between irreparable restoration fractures and the type of support material present in the opposing arch were found. CONCLUSIONS: In a period of up to 5 years, the resin cuspal coverage of endodontic treated teeth had a success rate of 96%, while the tooth survival rate was 100%. The type of support material on the opposing arch may influence the longevity of the restoration of endodontically treated teeth.

Microleakage of Different Adhesive Systems in Primary Molars Prepared by Er: YAG Laser or bur.

BACKGROUND AND AIM: This study aimed to examine the microleakage of class V cavities of primary molars prepared by either a conventional dental bur or Er:YAG laser and one of two different adhesive systems. METHODS: A total of 50 tooth samples from primary molars were used in this study. They were randomly assigned into five experimental groups of 10 samples each, according to the cavity preparation technique and the type of adhesive system applied to the cavities. Following cavity preparation, etching, bonding, and filling steps, samples were dyed using basic fuchsine and were sectioned longitudinally in buccolingual direction. Percentages of dye penetration at gingival and occlusal margins were calculated for each group. RESULTS: Overall, microleakage scores of gingival margins were significantly higher than those of occlusal margins (P < 0.001). The group that underwent laser preparation, laser etch, and self-etch bonding procedures had worse microleakage scores for gingival margins. However, all groups had similar occlusal scores (P > 0.05). CONCLUSION: Self-etch bonding systems and cavity preparation with Er:YAG laser may be an alternative to conventional restoration of primary molars with compomers. Further studies are warranted to fully elucidate the effect of laser-based etching techniques in cavities prepared by laser.

Antibacterial Effect of Surface Pretreatment Techniques against Streptococcus Mutans.

OBJECTIVE: The aim of this study was to evaluate the antibacterial surface pretreatment methods against Streptococcus mutans within the infected dentin surface using a tooth cavity model. MATERIAL AND METHODS: Seventy-two cavities were prepared on caries-free third molars (n = 8). After sterilization, teeth were inoculated with S. mutans for 48 h. One cavity of each tooth was used to evaluate the infection. Following inoculation, infected cavity surfaces were treated either with (1) Er:YAG Laser (1W; 5x5s, Smart 2940D Plus, Deka Laser), (2) Ozone (80s; HealOzone, Kavo), (3) ErYAG-Ozone combination, (4) Er:YAG-Ozone-CHX combination, (5) Chlorhexidine (CHX), (6) Clearfil Protect Bond (PB), (7) potassium-titanyl-phosphate (KTP) Laser (1W; 60 s, SMARTLITE D, Deka Laser), (8) KTP-Ozone combination, and (9) KTP-Ozone-CHX. Standardized amounts of dentin chips were obtained from the cavity walls, and the number of bacteria recovered was counted. Kruskal-Wallis test was used for statistical analyzes. RESULTS: Both sole antibacterial materials, CHX or Protect Bond application, exhibited the most effective antibacterial activity with 125 and 156 CFU is an acronym of "colony forming unit" usullay mentioned by acronym. (CFU/ml), respectively, among the groups evaluated (P < 0.05). Er:YAG laser irradiation and its combinations with other antibacterial surface pretreatment applications also inhibited the bacterial growth with, respectively, 1444, 406, and 294 CFU/ml bacterial recovery being more efficient than KTP laser irradiation and ozone combinations. CONCLUSIONS: As an alternative device with photodynamic effects, Er:YAG and KTP laser irradiations and their further combinations during the cavity pretreatment procedure with chlorhexidine and ozone treatments exerted antibacterial effect against S. mutans, whereas chlorhexidine and antibacterial dentin bonding application solely have the highest antibacterial effects.