Human Teeth Research Articles

An evaluation by dental clinicians of cutting characteristics and haptic perceptions in 3D-printed typodont teeth: A pilot study.

This study aimed to compare the haptic perception of clinicians to the cutting response of 3D-printed typodont teeth and commercial typodont teeth and human extracted teeth. Twenty clinicians were asked to perform a Class I cavity preparation on commercial typodont teeth, 3D-printed typodont teeth, and human extracted teeth, while the forces were recorded via a three-axis load cell. The haptic perception of clinicians was also evaluated through a response questionnaire comparing commercial and 3D-printed typodont teeth. The study found that clinicians used similar forces (p=0.53) to cut both the 3D-printed typodont teeth (1.37 N) and the human extracted teeth (1.44 N), but more force was needed to cut the commercial typodont teeth (3.71 N). The response questionnaire indicated that clinicians rated the 3D-printed typodont teeth highly compared to the commercial teeth. The 3D-printed dentine received favorable feedback from clinicians, and the 3D-printed enamel was rated higher compared to the commercial equivalents. The results of the study suggest that 3D-printed typodont teeth offer a comparable haptic perception to human extracted teeth and can be used as an effective tool for preclinical dental learning. Moreover, the study highlights the advantages of 3D-printed typodont teeth over commercial typodont teeth in terms of haptic perception.

Root canal cleanliness and debris extrusion following retreatment of thermoplastic injection technique and bioceramic-based root canal sealer.

To evaluate the amount of apically extruded debris and to determine the remaining filling material on the root canal walls by microcomputed tomography (micro-CT), following the root canal retreatment of root canals filled with different obturation techniques (single cone technique, thermoplasticised injection technique) and the different root canal sealers [bioceramic-based, epoxy resin-based root canal sealer]. 60 single rooted human premolar teeth were prepared with the ProTaper Gold system (Dentsply Maillefer) up to the F4 file and the samples were divided into 4 groups according to obturation procedures: Single cone technique + AH Plus sealer(epoxy resin-based root canal sealer, Dentsply International Inc., York, PA, USA); Single cone technique + Sure-Seal Root(bioceramic-based root canal sealer, Sure Dent Corporation, Gyeonggi-do, South Korea); thermoplastic injection technique[Calamus Dual Obturation System(Dentsply-Tulsa Dental, Tulsa, OK, USA)] + AH Plus(Dentsply International Inc.); Sure-Seal Root(Sure Dent Corporation) + Calamus Dual Obturation System (Dentsply-Tulsa Dental). The teeth were inserted into preweighed Eppendorf tubes and retreatment was performed. The tubes were kept in an incubator at 37°C for 14days to obtain the dry debris weight. Following the removal of the root canal fillings, the samples were scanned with a micro-CT device to analyse the volume of filling residues. Retreatment of samples obturated with epoxy-resin or bioceramic based root sealers combined with Calamus system resulted in higher amount of apical extrusion compared to their combination with single cone technique (p = 0.026 for Single cone technique + AH Plus sealer vs Calamus + AH Plus sealer and p = 0.005 for Single cone technique + Sure-Seal root sealer vs Calamus + Sure-Seal root sealer). The most debris was observed in the Calamus + Sure-Seal root sealer group, the least debris was observed in the Single cone technique + AH Plus sealer group. The percentage of residues was the highest in the Single cone technique + Sure-Seal root sealer and the lowest in the Calamus + AH Plus sealer group, but there were no significant differences between groups (p = 0.463). No correlation was observed among the groups in terms of extruded debris and remnants inside the root canal. When combined with bioceramic based sealer, thermoplasticised injection technique did not affect the cleanliness of root canal walls; however, it increased its apical extrusion potential during retreatment. The obturation method does not play a role in the removability of bioceramic based root canal sealer, however the use of bioceramic-based root canal sealers with cold obturation techniques may be beneficial in preventing apical extrusion.

An in vitro evaluation of tensile strength of molar endocrown milled from various computer aided design and manufacturing materials

New computer-aided design and computer-aided manufacturing (CAD-CAM) materials have been reported to have suitable mechanical and physical properties for endocrown restorations. However, there is a lack of literature on evaluating the retention of endocrown using these materials. This in vitro study aimed to compare the retention of endocrowns fabricated from 3 different CAD-CAM materials. Sixty human mandibular third molars were divided into 3 groups (n = 20) according to the material used: (e.max CAD, Ivoclar AG, Schaan, Liechtenstein), (HC, Shofu, Koyoto, Japan), and (Brilliant Crios, Coltene, Altstätten, Switzerland) (n = 20). Specimens were stored in distilled water at 37 °C for 1 week and subjected to 5000 thermal cycles. A universal testing machine (5500R/1123, Instron, Norwood, USA) was used to measure the tensile force. All results were statistically analyzed using one-way ANOVA (α = 0.05), and different failure modes were demonstrated. The results revealed that e. max CAD showed the highest mean tensile force value (402.35 ± 15.812) N, and the lowest mean tensile force value was for Brilliant Coris (118.90 ± 12.430) N (P < .001). It is concluded that e.max CAD endocrowns showed the highest tensile force values after thermocycling in comparison to other materials with a significant difference, which may have a promising impact on the survival of endocrown restorations.

IUP Technological Signatures or Mousterian Variability? The Case of Riparo l'Oscurusciuto (Southern Italy)

In the Italian peninsula, the Late Middle Paleolithic exhibits significant technological diversity, featuring blades, points, and bladelets. Assemblages displaying these distinctive characteristics have, in some cases, been labeled as Musteriano evoluto or Evolved Mousterian, and they are interpreted as contributing to the technological and typological variability within the Middle Paleolithic. In this study, we report the results of a detailed technological analysis of the lithics recovered from the latest layers preserved at Riparo l’Oscurusciuto (SU1 to SU3) in southern Italy. These layers were previously attributed to the Late Mousterian based on their chronological age and a preliminary techno/typological analysis of a small number of artifacts. Our comprehensive analysis of entire assemblages reveals the presence of original technological features, including blades, bladelets, and specific production of micro-points on flake cores. Some of these technological traits are comparable to those recently described at Grotte Mandrin in south-eastern France, which have been attributed to an early phase of the Initial Upper Paleolithic and associated with one modern human tooth. The study confirms the variability of the Late Middle Paleolithic in southern Italy and emphasizes the necessity to reassess it considering recent theories on the earlier arrival of Homo sapiens in Europe and their potential interaction with local populations.

Efficacy of Sodium Fluoride and Fluoridated Calcium Phosphate in Mitigating Dental Erosion on Human Enamel: An In Vitro Analysis.

With increasing prevalence of dental erosion, this study explores the protective role of traditional fluoride-based products and newer formulations on eroded enamel. To assess the protective effectiveness of casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) and sodium fluoride (NaF) on human enamel against erosion using surface microhardness (SMH) and Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses. Ten extracted human third molars were sectioned to obtain 40 enamel sections and randomly assigned into four groups (n = 10) and treated as follows: G1 (Sound Enamel), G2 (Erosive Challenge), G3 (CPP-ACPF + Erosive Challenge), and G4 (NaF + Erosive Challenge). All samples were subjected to Vicker's SMH analysis, while changes in surface morphology and elemental composition were validated in few representative samples using FTIR and SEM, respectively. Paired samples test, Kruskal-Wallis test, and Tukey HSD test were performed using SPSS software version 23 setting P value < 0.05 as statistically significant. The mean SMH1 values for the experimental groups G3 and G4 were significantly higher (426.58VHN and 455.83VHN) when compared to G1 (P = 0.000) and G2 (P = 0.000). In SEM analysis, G2 showed eroded honeycomb appearance compared to the smooth homogenous surface of G1, while both G3 and G4 showed deposition of some precipitates. FTIR analysis revealed that in G3 and G4, a characteristic peak of phosphate vibrations between 528 and 823 cm-1 and carbonate bands at 845-932 cm-1 was observed. Both CPP-ACPF and NaF demonstrated a protective effect on enamel against erosive challenge by an orange juice-based beverage.

Investigation of the Effect of Indirect Ultrasonic Force and Different Cements on the Bond Strength of Glass Fiber Posts in Teeth with Different Post Space Preparation Methods

(1) Background: The main aim of this study was to investigate the effects of different cements (Panavia V5, RelyX U200) and placement techniques (indirect ultrasonic vibration and manual method) on the bond strength of glass fiber posts in teeth with different post space preparation methods and to evaluate the failure types. (2) Methods: A total of 120 human upper central teeth were collected for the study. One week after root canal treatment, 10 mm long post space preparation was performed using post drills. Post spaces were irrigated in three different ways, namely NaOCl, NaOCl + EDTA solutions, and passive ultrasonic irrigation of NaOCl and EDTA solutions. Glass fiber posts were divided into two groups for resin cement systems, namely RelyX U200 (3M ESPE) or Panavia V5 (Kuraray Medical). Two different methods, namely the indirect ultrasonic vibration and the manual method, were applied for post placement. Then, 1.2 mm sections were taken from the middle and coronal regions of the inserted fiber posts for a push-out test. (3) Results: the Irrigation × Cement (p = 0.002), Cement × Section (p = 0.043) and Placement × Section (p = 0.049) pairwise interactions were statistically significant. (4) Conclusions: in our study, the effects of different post cavity preparations, different cement types, and different placement techniques on the bond strength of the fiber post were observed.

Chromatic Adaption of Two Universal Composites: Spectrophotometric Analysis

Objective: The purpose of this study was to evaluate the chromatic adaptability and color stability of two different composite resins, Omnichroma and Estelite Bulk-Fill Flow, in Class V restorations at different times. Materials and methods: Standardized Class V cavities were prepared on the labial surface of 34 extracted intact and noncarious human permanent molars. The dental elements were randomly divided into two groups according to the resin composite material. Group 1 was restored with Omnichroma (Tokuyama Dental Corporation Inc., Tokyo, Japan) and Group 2 was restored with Estelite BulkFill Flow Universal (Tokuyama Dental Corporation Inc., Tokyo, Japan). Color properties were assessed using a spectrophotometer, SpectroShadeTM Micro (MHT Optic Research, Niederhasli, Switzerland), at baseline (T0), immediately after Class V restoration (T1), 24 h after restoration (T2) and after thermocycling (T3) (ISO/TS 11405, 2015 protocol). Color difference (ΔE) was analyzed with a Student’s t-test and a Wilcoxon–Mann–Whitney test to evaluate the differences, in terms of chromatic adaptability, between the two materials (inter-group analysis) while Kruskal–Wallis test e Two-way ANOVA statistical tests were used to evaluate the color stability of each material over time (intra-group analysis). Results: Regarding the inter-group analysis, there were no statistically significant differences between the two materials in all the comparisons: T0–T1 (p = 0.9025), T0–T2 (p = 0.2779), T0–T3 (p = 0.4694). Moreover, both groups showed an average ΔE &gt; 2. In the intra-group analysis, no statistically significant differences were observed in either Group 1 (p = 0.954) or Group 2 (p = 0.8654). Conclusions: The in vitro color matching, assessed by spectrophotometry, of the two tested resin composites does not vary at different time intervals. Furthermore, even though both composites use different mechanisms to produce the color the human eye perceives, they show very similar chromatic adaptability.

Effect of Er:YAG Laser-Activated Irrigation with Side-Firing Spiral Endo Tip on Dentin Mineral Composition of Tooth Root Canals

Background: Treating tooth root canal systems with Er:YAG laser together with irrigants has been shown to be effective in reducing biofilms formed by Enterococcus faecalis. This study investigated whether laser-activated irrigation (LAI) with side-firing Endo tip (LiteTouch™; Light Instruments, Yokneam, Israel) affects dentin mineral composition when used with common endodontic irrigants. Methods: Root canals of extracted human teeth were treated with Er:YAG laser using a side-firing Endo tip combined with 17% ethylenediaminetetraacetic acid (EDTA) and/or 2.5% NaOCl in continuous or intermittent mode for 60 s. Dentin mineral composition (Ca, P, O) in coronal, middle, and apical regions of root canals was examined by energy dispersive X-ray spectroscopy. Results: The use of LAI with continuous EDTA resulted in the largest reduction in Ca and P levels. A final NaOCl rinse mitigated the EDTA-mediated mineral loss in all root canal regions and increased the O content. Likewise, the reduced Ca/O and Ca/P ratios caused by continuous EDTA irrigation were reversed when combined with a final NaOCl rinse. Conclusions: LAI with Er:YAG Endo tip using continuous EDTA irrigation followed by NaOCl caused minimal dentin mineral loss and can therefore be considered to be a safe treatment module for cleaning root canals.

The Harmful Effects of Welding Fumes on Human Dental Enamel-A Microhardness Analysis.

Introduction: Over the years, welding fumes' harmful effects have been demonstrated countless times in the scientific literature. Recently, studies in the field have shown an increasing interest in the negative consequences that these fumes may have on the tissues of the oral cavity. Materials & method: The current study aimed to investigate the impact that welding fumes have on the structure of human dental enamel by analyzing the microhardness of the dental enamel in 15 extracted human teeth, after various exposure times, using the Vickers method. Results: The results obtained after 48, 96, 168, and 336 h of direct exposure of the extracted specimens to the welding fumes show a statistically significant increase in the depreciation of the dental enamel's microhardness, related to the duration of exposure (p < 0.05). An average of 305 Vickers units was observed at the longest exposure time, 336 h, in the present study, whereas in the control group, the microhardness analysis showed an average of 327 Vickers units.

A pilot study examining periodontally healthy middle-aged humans and monkeys display different levels of alveolar bone resorption, gingival inflammatory infiltrate, and salivary microbiota profile.

Monkeys are an appropriate model for periodontal research owing to their similar dental anatomy and physiology unlike humans. Extensive literature exists on pathological periodontitis in monkeys and humans, although concerns regarding whether healthy middle-aged monkeys and humans display the same periodontal and oral microbial status remains unclear. The current study aimed to compare alveolar bone resorption, gingival inflammatory infiltrate, and salivary microbiota profile in periodontally healthy middle-aged humans and monkeys. CBCT examination and histological analysis were performed to compare the periodontal status in middle-aged healthy humans and monkeys. Oral saliva16S rRNA sequencing was performed to analyze the oral microbial profile. The alveolar resorption was compared between humans and monkeys, to determine the periodontal health. The percentage attachment of attachment loss was more around the posteriors teeth in humans when compared to monkeys (p<0.05). The degree of gingival inflammation was analyzed in both the groups, the expression of CD 34,45was higher in humans. 16S rRNA analysis demonstrated less diversity of salivary microorganisms in humans than in monkeys. The relative abundance of Aggregatibacter, Haemophilus, Gemella, and Porphyromonas at the genus level was significantly less in humans than in monkeys (p(<0.05). The periodontally healthy middle-aged humans and monkeys display different alveolar bone resorption and gingival inflammatory infiltrate levels. Furthermore, the salivary microbiota profile showed distinctly different oral microbiomes in these two primates. Our results suggest that the difference in alveolar bone status and gingival inflammatory infiltrate in healthy humans and monkeys might be associated with the diversity of the oral microbiome.

ProDesign Logic Files Effect on Apical Foramen Wear and Shape Transformation After Foraminal Enlargement.

This study aimed to evaluate the effect of ProDesign Logic files 45.01 and 50.01 on apical foramen wear and shape transformation after foraminal enlargement at tooth length (TL) and 1 mm beyond. Sixty freshly extracted single-rooted lower human premolars teeth were distributed randomly into five groups (n = 12): Group 1 (40.05 WL) (control): No foraminal enlargement, Group 2 (45.01 TL): Specimens underwent foraminal enlargement with 45.01 Prodesign Logic file at TL; Group 3 (45.01 TL + 1): Specimens underwent foraminal enlargement with 45.01 Prodesign Logic file at 1 mm beyond TL; Group 4 (50.01 TL): Specimens underwent foraminal enlargement with 50.01 Prodesign Logic file at TL; Group 5 (50.01 TL + 1): Specimens underwent foraminal enlargement with 50.01 Prodesign Logic file at 1 mm beyond TL. Scanning electron microscopy was used to evaluate apical foramen variations and shape alterations. Data were analyzed by Student's t-test, Kruskal-Wallis, and Mann-Whitney test. Significant differences (p < 0.01) were observed among all tested groups compared to the control group in terms of the average worn area of the apical foramen. Foraminal enlargement led to significant shape transformation, resulting in round-shaped foramina. ProDesign Logic 45.01 and 50.01 files at TL causes notable wear and round-shaped foramina.

Effects of Acid Etching on the Microstructure and Stiffness of Human Teeth

Abstract The mechanical properties of acid-etched enamel and dentin are important for understanding tooth erosion and developing innovative dental restorative materials. In this study, the microstructure and mechanical properties of both enamel and dentin were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) to quantify the impact of acid etching. SEM images demonstrated that enamel rods have a diameter of approximately 5 μm, while dentinal tubules have a diameter of around 2 μm. After acid etching, the intertubular and peritubular regions were exposed, with the peritubular regions showing a thickness of approximately 1 μm. AFM measurements showed that the stiffness of enamel at the bottom, middle, and top layers is 26.28±4.24 GPa, 32.03±8.68 GPa, and 23.94±3.53 GPa, respectively. For dentin, the stiffness is 16.28±2.76 GPa at the bottom layer and 17.59±5.33 GPa at the middle layer. AFM morphology and stiffness maps illustrated the microstructures of enamel rod and sheaths, as well as dentin tubules in both unetched and acid-etched tooth sections. The stiffness of the acid-etched enamel rod and peritubular dentin decreased by 7-fold and 3.6-fold, respectively, compared to the unetched enamel rod and peritubular dentin.

Weapon of Assault: Combat, Protective Magic, and the Fatal Throat Bite in Icelandic Sagas

Abstract Icelandic sagas contain a literary motif little known in other pre-modern literary traditions: the throat bite. There are 10 scenes in the sagas in which one character bites, almost bites, or contemplates biting the throat of another character. The throat bite was used by saga authors strategically and purposefully, whether to resolve conflict, similar to a more conventional murder; to signify paranormal characteristics – or lack of paranormal characteristics; or to denote interpersonal power dynamics within a saga narrative. Due to the prevalence of the throat bite in extra-narrative contexts, including its use as hunting technique among non-human animals and the documented use of human teeth as a weapon among human populations, the saga writers of medieval Iceland accurately recognized that human teeth can serve as a weapon of assault and they craftily integrated the throat bite into the composition of select sagas.

Deep learning for diagnostic charting on pediatric panoramic radiographs.

Artificial intelligence (AI)-based systems are used in dentistry to ensure a more accurate and efficient diagnostic process. The objective of the present study was to evaluate the performance of a deep learning (DL) program for the detection and classification of dental structures and treatments on panoramic radiographs of pediatric patients. In total, 4821 anonymized digital panoramic radiographs of children between 5 and 13 years of age were analyzed by YOLOv4, a CNN (Convolutional Neural Networks)-based object detection model. The ability to make a correct diagnosis was tested on samples from pediatric patients examined within the scope of the study. All statistical analyses were performed using SPSS version 26.0 software. The YOLOv4 model diagnosed the primary teeth, permanent tooth germs, and brackets successfully, with high F1 scores of 0.95, 0.90, and 0.76, respectively. Although this model achieved promising results, there were certain limitations for some dental structures and treatments, including fillings, root canal treatments, and supernumerary teeth. The architecture of the present study achieved reliable results, with some specific limitations for detecting dental structures and treatments. The detection of certain dental structures and previous dental treatments on pediatric panoramic radiographs by using a DL-based approach may provide early diagnosis of some dental anomalies and help dental practitioners to find more accurate treatment options by saving time and effort.

Effect of immediate dentin sealing on the fracture strength of indirect posterior restorations:Systematic review and meta-anlysis protocol.

Background Immediate Dentin Sealing (IDS) is a technique that applies an adhesive layer immediately after tooth preparation, prior to the placement of indirect restorations. This method is gaining attention due to its potential to improve the bond strength and mechanical properties of restorations, particularly in the posterior region where restorations endure significant masticatory forces. The objectif of this systematic review and meta-analysis is to evaluate the effect of IDS on the fracture strength of indirect posterior restorations. Methods Following PRISMA guidelines, a comprehensive literature search was conducted in four databases: Web of Science, Scopus, Cochrane Library, and PubMed. Inclusion criteria focused on in vitro studies involving human teeth with indirect posterior restorations, published between 2014 and 2023. Studies using IDS were compared to those using conventional methods. The risk of bias was assessed using the Cochrane Collaboration’s tool, and a meta-analysis was performed with a random-effects model. The standard mean difference and 95% confidence intervals were calculated to compare fracture strength, with I2 statistics assessing heterogeneity. Forest and funnel plots were employed to visualize results and publication bias, respectively. Discussion The results indicate that IDS generally enhances the fracture strength of indirect posterior restorations, particularly with ceramic materials like lithium disilicate. However, the effectiveness of IDS varies depending on the material and restoration type. While some studies demonstrated improved fracture resistance with IDS, others showed minimal benefit, especially with composite restorations. Additionally, IDS improved marginal adaptation and internal fit but increased the risk of severe failures, such as root fractures. Systematic review registration PROSPERO: CRD42024584545 (Registered on 08/09/2024).

Immunohistochemical Expression of MDM2, Bcl-2, SATB2 and Ki-67 in Histological Variants of Unicystic Ameloblastoma.

To characterize the immunohistochemical expression of MDM2, Bcl-2, SATB2 and Ki-67 in histological variants of unicystic ameloblastoma (UA). Following the ethical approval, forty (40) patients with unicystic ameloblastoma were retrieved from the archives and subjected to immunohistochemistry (IHC). Sociodemographic and clinical data were also retrieved. The results were entered into a Microsoft Excel spreadsheet and analyzed using SPSS software. Human tooth germs, which served as the control, showed moderate expression of Bcl-2 and MDM2 with slight proliferative activity in ameloblasts and moderate expression of SATB2 in ectomesenchyme and odontoblasts. Luminal UA (Type 1) showed low Ki-67 index and negative to mild Bcl-2 and MDM2 expression, whilst Type 1.2 (luminal and intraluminal), Type 1.2.3 (luminal, intraluminal and mural), and Type 1.3 (luminal and mural), including the recurrent cases, showed moderate to intense expression with high mean Ki-67 index. The difference between the study groups was statistically significant (p value < 0.001). No expression of SATB2 was noted in any histological variant of UA. Furthermore, no significant differences were noted in age, gender, site and location between the groups. In contrast to luminal variant of UA, mural±intraluminal variants and recurrent cases demonstrate higher expression of Bcl-2 and MDM2 with higher mean Ki-67 index. It may thus be prudent to provide aggressive treatment for cases, not just with mural follicles but also for the patients with intraluminal plexiform proliferation, to prevent recurrence and improve patient outcomes.

Penetration of Intracoronal Bleaching Agents Across a Calcium Silicate-Based Coronal Barrier in Pulpless Immature Permanent Teeth: An In Vitro Study.

Tooth bleaching procedures on nonvital teeth have been performed for crown discoloration caused by regenerative endodontic therapy (RET). However, leakage of bleaching agents across the root canal can be detrimental. This study aimed to assess and compare the penetration levels of hydrogen peroxide (HP) from different bleaching agents across calcium silicate-based coronal barriers in immature permanent teeth. Fifty extracted single-rooted human teeth were randomly divided into four groups (n = 10): Group I (HH)-35% hydrogen peroxide (HP); Group II (SS)-a mixture of sodium perborate (SP) powder and saline; Group III (SH)-a mixture of SP powder and 30% HP liquid; Group IV (CP)-10% carbamide peroxide gel. The control group (Group V, CC) was treated with distilled water. The bleaching agent was replaced on the 4th day, and penetration analysis was performed on the 7th day using ferro thiocyanate (FTC) method and a UV-spectrophotometer at a wavelength of 480 nm. Compared with the control group, the SH group (SP mixed with HP) showed a significant difference, indicating substantial HP penetration across the root canal space (p value < 0.0001). Intergroup comparisons also revealed a significant difference between the SS and SH groups (p value < 0.0001), suggesting that the SS group had less penetration. Compared with other bleaching agents, SP mixed with saline/water resulted in the lowest HP penetration in the pulp canals of the RET-simulated tooth models. This study is the first to investigate HP penetration from different bleaching agents in teeth that have undergone RET, identifying the safest bleaching agent for use in these cases. This study also provides a foundation for further research to develop precise guidelines for nonvital tooth bleaching protocols in RET-treated teeth.

Evaluation of Shear Bond Strength of Universal Adhesives to Dentin: in Vitro Study

Aim: Universal adhesives are widely used in restorative dentistry. The aim of this study was to evaluate the shear bond strength (SBS) of universal adhesives to dentin in different application modes. Materials and Methods: The study utilized seven universal adhesives and one total-etch adhesive. The sixty-four extracted intact human molars used in the study were embedded in acrylic blocks to the enamel-cement junction. The occlusal surface was removed to expose the dentin surface. After applying self-etch and total-etch adhesives to the dentin, flowable composite (Clearfil Majesty Flow, Kuraray) was placed in a transparent mold (2.38 mm diameter and 2 mm height) and polymerized. After thermal aging (1000 cycles), a SBS test has been carried out on a universal testing machine. The fracture types formed on the surface of the teeth were examined under a microscope. Data were analyzed by two-way analysis of variance (ANOVA) test (p&lt;0.05). Results: SBS values of universal adhesives on dentin showed statistically significant differences according to adhesive and application mode (p&lt;0.05). Total-etch application produced statistically higher SBS than self-etch application (p&lt;0.05). The two-step universal adhesive (G2 Bond Universal) had the highest SBS in both the self-etch and total-etch application modes (p&lt;0.05). When the bond surfaces of the universal adhesives were examined, fractures occurred most frequently in the adhesive type. Conclusion: The use of universal adhesives in the total-etch mode results in greater bond strength to dentin tissue. Universal adhesive type influences bond strength.

Unusual presentation of lower right second molar: A case report

Introduction: Dental anomalies such as fusion and gemination are rare but clinically significant conditions that can complicate diagnosis and treatment. This report presents a unique case involving the lower right second molar in a young adult male, exploring the diagnostic challenges and therapeutic implications. Case Report: A 20-year-old male patient presented for a routine dental check-up during which an unusual morphology of the lower right second molar was observed. Radiographic analysis suggested a dental anomaly, with differential diagnoses including fusion and gemination. The clinical presentation, radiographic findings, and subsequent management are discussed in detail. Conclusion: Accurate diagnosis of dental anomalies is crucial for effective treatment planning and management. This case underscores the importance of detailed clinical and radiographic evaluation in identifying and differentiating between dental conditions like fusion and gemination.

Comparative evaluation of the strength of adhesion by push-out bond strength tests on endodontic posts cemented with different resinous types of luting cements: An in vitro study

INTRODUCTION. Endodontic posts play a vital role in strengthening debilitated teeth. They are luted into the radicular space using dental cements that are generally resinous. Given that the forces faced by human teeth are loading in nature and the stresses are accumulative, the bond strength of the interfaces at both the radicular dentin and luting agent and the endodontic post and the luting agent needs to be evaluated. Micro pushout bond strength (POBS) testing is done to determine these strengths. This experimental, in vitro study evaluated the adhesion strength of endodontic posts cemented with different resin-based luting agents using micro-POBS.MATERIALS AND METHODS. A total of 30 human lower incisors were selected and divided into three groups (n=10), based on the type of adhesive resin cement used for luting. Prefabricated endodontic fiber posts were inserted into the root canals of each tooth, and different resin types of cement – Estecem II, Multilink Automix, and Relyx Ultimate. were used to cement the fiber posts. The micro-POBS test measured the bond strength of the cemented pins to the root canal dentin.RESULTS. The results showed that the mean POBS of Group B was higher than that of Group A and Group C. The difference between the mean POBSs of Group A and Group C was not statistically significant (p&gt;0.05).CONCLUSION. The resin adhesive cement used can affect the POBS of endodontic posts to root canal dentin. Clinicians should choose the appropriate resin cement for cementing endodontic posts to ensure a strong and durable bond for a good clinical prognosis.