Enamel Junction Research Articles

Evaluation Of Bone Thickness At Different Anatomical Sites In Infrazygomatic Crest For Miniscrew Insertion In Skeletal Class II Patients – A CBCT Study

AIM: To assess infrazygomatic crest bone thickness at different anatomical sites at a distance of 5mm, 7mm, 9mm and 11mm apical to cementoenamel junction, 70 degree to occlusal plane in skeletal class II patients using cone beam computed tomography (CBCT). Materials and Methods: The sample consists of cone beam computed tomography images of 23 class II subjects were evaluated. Infrazygomatic crest bone thickness was evaluated at the six horizontal regions (i) interdental area between maxillary second premolar (PM2) and first molar(M1) (ii) Mesiobuccal root of maxillary first molar (MB root of M1) (iii) Distobuccal root of maxillary first molar(DB root of M1) (iv) interdental area between maxillary first molar(M1) and second molar(M2) (v) Mesiobuccal root of maxillary second molar(MB root of M2) (vi) Distobuccal root of maxillary second molar (DB root of M2) at a vertical distance of 5mm,7mm,9mm and 11mm apical to cementoenamel junction, 70 degree to occlusal plane. Results: The buccal bone thickness increase from mesial surface of maxillary first molar to mesial surface of maxillary second molar from cement enamel junction at the level of 11mm, 70 degree to the occlusal plane. The bone thickness decreases at the second molar level. Conclusion: The safe site for insertion of miniscrews in the infrazygomatic crest were the interdental region between the maxillary first and second molars at the heights of 11 mm from cementoenamel junction and 70 degree to the occlusal plane

Tissue Dissolution Ability of Sodium Hypochlorite, EDTA, Ambroxol Hydrochloride and Triphala Evaluated and Compared when used as an Irrigant on Bovine Pulp Tissue

Aim: The aim of the study is to evaluate pulp tissue dissolution ability of Sodium hypochlorite (NaOCl), Ethylenediaminetetraacetate (EDTA), Ambroxol hydrochloride and Triphala.  Methods: Pulp tissue of BOS Taurus primigenius was extracted from 20 mandibular incisors of 4 bovine jaws .Decoronation was done at the cementum–enamel junction and roots were resected at a length of 3 mm from the apex with a diamond disc connected to a electric micromotor. Pulp tissue was then taken out of the pulp chamber of the bovine tooth with a periodontal probe and cotton pliers. Specimens were weighed using a hermetic precision electronic balance (AND Company LTD) before the test to analyze the initial weight (T0) of the samples. Extracted bovine pulp tissue specimens were weighed and randomly distributed in to 4 experimental groups of 3% sodium hypochlorite, 17% EDTA, Ambroxol hydrochloride(35mg/ml), Triphala(100mg/ml) that were taken in 4 centrifugation tubes. Contents are filtered and undissolved tissue remnants collected and reweighed.  Results: Results obtained indicate that highest pulp dissolution is for NaOCl, followed by EDTA, Ambroxol Hydrochloride and least for Triphala.  Conclusion: Highest pulp dissolution is for NaOCl, followed by EDTA, Ambroxol Hydrochloride and least for Triphala.

A Minimally Invasive Surgical Procedure to Harvest Palate Periosteum as a Source of Mesenchymal Stromal/Stem Cells for Bone Tissue Engineering.

The aim of this study is to validate a minimally invasive surgical procedure to harvest palate periosteum as a source of tissue for mesenchymal stromal/stem cells. We performed a standardized procedure to harvest the palate periosteum in ten subjects, which consisted of a 3 mm disposable punch and a Molt periosteal elevator to harvest a small full-thickness fragment of soft tissue at the hard palate area, between the upper bicuspids, 3 to 4 mm apical to the cement enamel junction. The one-third inner portion was fragmented, and following standard cell culture procedures, the adherent cells were cultured for three passages, after obtaining 70-90% confluence. Cell morphology analysis, flow cytometry analysis, and viability and osteogenic differentiation assays were performed. In all 10 cases, uneventful healing was observed, with no need for analgesic intake. The evaluation of cell morphology showed elongated spindle-shaped cells distributed in woven patterns. A high viability range was verified as well as an immunophenotype compatible with mesenchymal stem cell lineage. The differentiation assay showed the potential of the cells to differentiate into the osteogenic lineage. These results demonstrate that the minimally invasive proposed surgical technique is capable of supplying enough periosteum source tissue for stem cell culture and bone tissue engineering.

Comparison of the efficacy of tricalcium phosphate and mineralized plasmatic matrix graft for the bone defect in the distal second molar tooth after surgery of the lower impacted third molar tooth

Aim: After the extraction of mandibular horizontal and mesioangular teeth, a defect occurs in the distal part of the second molar. In this study, the effect of MPM on these defects was evaluated. Materials and methods: 36 patients randomly divided into 3 groups. The first group included MPM and PRF. The second group included B-tcp and PRF. In the 3rd group, the extraction socket was left empty. At preoperative and postoperative 6th months, periodontal pocket depth, gingival index and plaque index, and the distance between the enamel junction and crestal bone at the distal of the 2nd molar were measured by CBCT. 8 patients were removed for various reasons. 28 patients were evaluated. Results: Preoperative and postoperative periodontal pocket depths at the sixth month were 7.67 ± 1.58 mm and 4.67 ± 1.23 mm in the MPM group (p<0.001); 6.60±1.96 mm and 4.70±1.34 mm in the β-TCP group (p<0.001); 6.78±1.48 mm and 5.56±1.01 mm in the control group (p<0.023). Bone defects preoperatively and at six months postoperatively were 7.97 ± 1.04 mm and 3.59 ± 0.66 mm in the MPM group (p<0,001); 6.23 ± 1.37 mm and 2.90 ± 1.04 mm in the β-TCP group (p<0.001); 6.92±0.82 mm and 4.30±0.68 mm in the control group (p<0.001). Conclusion: MPM is an effective graft material to restore the periodontal health of the distal part of the second molar after impacted lower third molar surgery

Comparative Evaluation of Solite RS3 and HyFlex Remover Retreatment Files in Conserving Remaining Dentin Thickness During Endodontic Retreatment Using Cone Beam Computed Tomography: An In Vitro Analysis.

Introduction Non-surgical retreatment is seen as a conservative choice for dealing with recurrent infections, instead of opting for periapical surgery. The retreatment processes should be promptly and efficiently carried out, utilizing a suitable armamentarium. The objective of this experiment is to evaluate the quantity of root dentin that remains following the removal of gutta-percha (GP) from the root canal employing two distinct retreatment files. Materials and methods Sixty single-rooted teeth were selected for the examination. The process of shaping and cleaning was performed using the step-back approach, with a master apical file size of 40. The smear layer was effectively eliminated by rinsing with a solution of 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Paper points were employed to desiccate the canals. The obturation process involved the utilization of the lateral compaction technique with the AH Plus sealer (Dentsply Sirona, NC, USA). The teeth were classified into two groups: Group I (n=30) underwent retreatment using HyFlex Remover (Coletene India, Pvt., Ltd.), whereas Group II (n=30) received therapy with Solite RS3 retreatment files (Solite Dental in Chennai, India). The remaining dentin thickness (RDT) was assessed by cone beam computed tomography at levels 3, 6, and 9 mm from the cemento enamel junction after the removal of GP. The acquired data underwent examination using an independent t-test to determine statistical significance. Results The findings demonstrate that the utilization of Solite RS3 files led to a higher level of dentin thickness remaining at 3 mm, 6 mm, and 9 mm on the mesial side in comparison to HyFlex Remover retreatment files. The observed difference was found to be statistically significant at a significance level of p<0.05 on the mesial side. Nevertheless, there was no notable disparity seen between the two file types at these three levels on the distal side (p>0.05). Conclusion Based on the obtained results of the study, it can be concluded that Solite RS3 files show promise in preserving the RDT. However, further studies encompassing diverse parameters are needed to establish a conclusive and definitive conclusion.

The effect of flowable composite and glass ionomer liner on the marginal integrity of class II composite resin restorations

Aim of the study To evaluate the effect of flowable composite and glass ionomer liner on the marginal integrity of Class II composite resin restorations. Materials and methods A total of thirty non-carious human maxillary molar teeth were mounted in acrylic blocks. Simple Class II cavity with parallel walls was prepared. The cervical margin was established 1.5 mm above the cemento- enamel junction. The overall dimensions and depth of the cavities were standardized as follow: 4 mm length occlusocervically, 4 mm width buccolingulaly and 2 mm depth axially. Specimens were randomly divided into three equal groups (10 each). Group 1: The cavities were restored with Xtra Fil bulk fill composite without liner. Group 2: Xtra base flowable composite (1 mm thickness) was applied, followed by Xtra Fil bulk fill. Group 3: Ionoseal glass ionomer was applied as a base (1 mm thickness), followed by Xtra Fil bulk. Specimens were then subjected to 500 thermal cycles from 5 to 55oC with 30 s dwell time, and 15 s transfer time. Impressions of the teeth were made using a polyvinyl siloxane material, poured with epoxy resin. These replicas were left 24 h for complete setting. Then, Gold sputtered to be examined under scanning electron microscopy (SEM). Results were expressed as percentage of open margins for the total margin length for proximal and cervical margins and also the width of the gap were measured. The recorded data was collected, tabulated, and statistically analyzed using SPSS version 25. Results It was found that there was a significant difference in total gap length between group 1 and group 2 with P value = 0.000. Where group 1 has the biggest marginal gap length and the smallest marginal gap length belongs to Group 2. While there was no significant difference between group 1 and group 3 with P value 0.124. It was also found that there was no significant difference between groups in marginal gap widths. Conclusions The use of flowable composite and glass ionomer as liner could reduce microleakage of bulkfill composite restorations.

Comparative study of the adaptation of alkasite versus self-adhesive flowable restorations

Aim To compare the adaptation of self-adhesive flowable composite versus alkasite restorations with or without the use of an adhesive system. Materials and Methods A total of 30 noncarious maxillary premolars were selected and mounted 2 mm below the cemento–enamel junction in acrylic blocks. Trapezoidal class V cavities were prepared on the buccal surface of each tooth. The gingival margins of the prepared cavities were located 1 mm above cemento–enamel junction. All cavity margins were not bevelled. During the experiment time, all samples were kept in artificial saliva renewed daily at 37°C in an incubator to prevent dehydration. These were randomly divided into three groups (n = 10). Alkasite restorative material was applied in a bulk fill technique using a universal adhesive in samples of group I, while those of group II did not have any adhesive using the same restorative material and those of group III were restored using self-adhesive flowable composite (vertise flow). Specimens of the three tested groups were subjected to 500 thermal cycles from 5 to 55°C with 30 s. Dwell time and 15 s transfer time. They were all immersed in methylene blue dye 2% for 24 h in an incubator. Then all samples were examined under stereomicroscopy at ×40 to determine the percentage of gap free length along the entire margins. All specimens were then sectioned buccolingually to detect the percentage of internal gap length along the restoration/tooth interface. Results Regarding the marginal adaptation, the highest % of marginal free gap was recorded for group I, while the lowest was recorded for group II. Concerning the internal adaptation, it was found that the highest % of free gap was related to group I and III while the lowest was related to group II. Comparing the marginal versus internal % of gap free margins it was found that group I versus II showed a statistically significant difference. Also, group III versus II showed a significant difference. While group I versus III recorded no statistically significant difference. This was true at both marginal and internal % of free gaps. These findings indicated the responsibility of group II for the recorded differences since group II showed the least % of free gap margins and the highest percentage of total dye penetration values. Conclusions Within the limitations of this in vitro study, the adhesive system was effective in increasing the percentage of free gaps of tested groups whether marginal or internal. Recommendations The use of any composite material is not recommended without an adhesive system. Further in vitro studies providing more precise gap measurement are required.

Characterizing the microstructures of mammalian enamel by synchrotron phase contrast microCT

The enamel of mammalian teeth is a highly mineralized tissue that must endure a lifetime of cyclic contact and is inspiring the development of next-generation engineering materials. Attempts to implement enamel-inspired structures in synthetic materials have had limited success, largely due to the absence of a detailed understanding of its microstructure. The present work used synchrotron phase-contrast microCT imaging to evaluate the three-dimensional microstructure of enamel from four mammals including Lion, Gray Wolf, Snow Leopard, and Black Bear. Quantitative results of image analysis revealed that the decussation pattern of enamel consists of discrete diazone (D) and parazone (P) bands of rods organized with stacking arrangement of D+/P/D-/P in all mammals evaluated; the D+ and D- refer to distinct diazone bands with juxtaposed rod orientations from the reference plane. Furthermore, the rod orientations in the bands can be described in terms of two principal angles, defined here as the pitch and yaw. While the pitch angle increases from the outer enamel to a maximum (up to ≈ 40°) near the dentin enamel junction, minimal spatial variations are observed in yaw across the enamel thickness. There are clear differences in the decussation parameters of enamel across species that are interpreted here with respect to the structural demands placed on their teeth. The rod pitch and band width of enamel are identified as important design parameters and appear to be correlated with the bite force quotient of the four mammals evaluated. Statement of significanceThe multi-functionality of tooth enamel requires both hardness and resistance to fracture, properties that are generally mutually exclusive. Ubiquitous to all mammalian teeth, the enamel is expected to have undergone adaptations in microstructure to accommodate the differences in diet, body size and bite force across animals. For the first time, we compare the complex three-dimensional microstructure of enamel from teeth of multiple mammalian species using synchrotron micro-computed tomography. The findings provide new understanding of the “design” of mammalian enamel microstructures, as well as how specific parameters associated with the decussation of rods appear to be engineered to modulate its fracture resistance.

Stereolithography-manufactured zirconia substrate with bionic-patterned surface microstructure for enhancing bond strength to porcelain veneer

The bond strength between the zirconia substrates and porcelain materials has been extensively investigated, and sandblasting is one of the most effective methods for increasing the bond strength between zirconia and porcelain. However, it also introduces microcracks and pollution, which have a negative impact on the final mechanical properties of zirconia restorations. To increase the mechanical chimaerism of zirconia/veneer structures nondestructively, in this study we developed a novel surface design called a bionic-patterned surface microstructure (BSM) using stereolithography (SLA) technology. Inspired by the dentin–enamel junction model, the microstructure includes a cylinder and pit. Among all the specimens, both computer numerical control (CNC) zirconia with sandblasting and SLA zirconia with BSM showed higher bond strengths than the CNC group (P < 0.001), and the BSM groups showed improved bonding properties (P < 0.001). No significant differences were observed between the cylindrical and pit BSM at the same height/depth (P = 0.493), and for BSM of the same type, the bond strength increased with increasing height/depth (P < 0.001). Zirconia with BSM thus had superior bond strength to porcelain veneers. The height/depth of the BSM had a positive effect on the bonding strength, whereas the type had no effect.

Comparative analysis of the remineralization potential of different active ingredients based toothpastes using SEM/EDX: An in vitro study

Background/Aim: The principal purpose of this study was to investigate the efficacy of different active ingredients to inhibit demineralization around the margins of cervical cavities in natural teeth by scanning electron microscopy and energy dispersive X-Ray elemantal analysis (SEM-EDX). Material and Methods: Thirty-two sound human molars were used. Box-shaped cavities were prepared along the cemento enamel junction (CEJ). The samples were were immersed in a demineralization solution (pH=1) maintained for 72 hours and randomly divided into 4 groups. Surfaces according to the groups were treated with potassium nitrate, arginine and calciumsodiumphosphosilicate containing remineralization agents for 14 days, respectively and the samples in control group were submitted to toothbrushing with deionized water. The samples were analyzed by using SEM-EDX analysis. Data was statistically analyzed using by one way ANOVA (analysis of variance) test and LSD (least significant difference) test for comparison between means at a significance level of 0.05. Results: SEM-EDX elemental mapping was used to evaluate the degradation from depth profiles of fluoride (F), Calcium (Ca), and phosphate (P) leaching. Micromorphological and elemental analyses were done using SEM and EDX. SEM EDX Analysis on enamel showed a significant difference between the groups except the control group (p&lt;0.05). The dentine results showed significant differences between the control group and all other groups (p&lt;0.05). Elemental analysis showed significant differences in Ca weight percentage among the first and second observation levels in all groups (p&lt;0.05). Conclusions: In conclusion, all tested toothpastes showed some ability to resist demineralization at the margins. The groups except control group showed better outcomes compared with the other tested samples.

Deleterious effect of chronic high-dose ethanol intake on biomechanical bone properties and periodontal status.

To evaluate the effect of high-graduation chronic ethanol (EtOH) intake on bone and periodontal tissues of rats. Male Wistar rats (250g) were divided into two groups of n = 12 each one. EtOH (5ml of 3g/kg) was administered to the experimental group by gastric gavage twice a day for 20days and the control group received water under the same conditions. The rats were euthanized and used to perform biochemical determination in plasma and gingival tissue, and histological and biomechanical studies in the femur and mandibular tissues. Alcohol increased both TNFα (p < 0.01) and PGE2 (p < 0.05) in plasma and gingiva (p < 0.05) as compared to controls. In addition, EtOH increased the alveolar bone loss as evidenced by the increased distance between the cement enamel junction and the alveolar crest (p < 0.01), the lower % of interradicular bone expressed as bone area/total area (B.Ar/T.Ar, p < 0.05) and the larger periodontal space (p < 0.05), as compared to controls. Likewise, the mandibular microtomographic analysis in alcoholized rats revealed a lower % of interradicular bone volume/total volume (BV/TV, p < 0.05), greater trabecular separation (p < 0.05) and greater % trabecular porosity (p < 0.05) than controls. No biomechanical alteration was observed in lower jaws, while the femur of alcoholized rats presented a decrease in the structural bone properties (p < 0.001), as a systemic consequence of deterioration of the diaphyseal architecture (p < 0.01) without changes in material properties. The consumption of high doses of alcohol produces deleterious effects on periodontal tissues that could be due not only to local but also systemic effects.

Restorations of Class II Cavities Evaluated for Marginal Leakage When Restored with Composites or a Giomer Using Different Bonding Agents.

To evaluate the marginal leakage of three different types of bonding agents used with two posterior composites and a giomer, available commercially. Class II box-only cavities were prepared on 90 mandibular first molars with margins extending 1 mm beyond the cementoenamel junction. The samples were divided into nine groups based on three different bonding agents, two different composites, and a giomer. Cavities were restored per the manufacturer's description. Teeth were subjected to a thermocycling procedure (500×, 5°C to 55°C) and dye penetration by immersing in a 2% methylene blue solution (Merck Specialties) for 24 hours. The marginal adaptation was evaluated as a continuous margin at the gingival level under a stereomicroscope. The results were analyzed using the Kruskal-Wallis and Mann-Whitney U tests. The results of the groups with the total-etch technique showed no statistical difference between the nanohybrid Filtek Z250 XT (3M ESPE) and fine hybrid SwissTEC composite (Coltène\Whaledent AG). The groups with the self-etch technique showed no statistical difference when used with either of the two composites. The acid-etch technique showed better marginal adaptation than the self-etch technique. When the giomer (Beautifil II, Shofu) was used with the total-etch technique, it showed better adaptation than when used with the self-etch technique but overall showed more marginal leakage than the composites. The total-etch technique provided better marginal adaptation for the composites and giomer compared to the self-etch technique. The demand for esthetic restorations continues to increase, and composite restorations are now considered the material of choice for Class II cavities. There are various concerns with composite restorations, one of them being good marginal adaptation to increase the life of the restoration. This study evaluated marginal leakage with the nanohybrid composite Filtek Z250 XT, fine hybrid composite SwissTEC, and a giomer when used with the total-etch technique and self-etch technique and reported satisfactory adaptation with the total-etch technique.

Mixed-Thickness Tunnel Access (MiTT) through a Linear Vertical Mucosal Incision for a Minimally Invasive Approach for Root Coverage Procedures in Anterior and Posterior Sites: Technical Description and Case Series with 1-Year Follow-Up.

The goal of this article was to introduce a new root coverage (RC) technique, the mixed-thickness tunnel access (MiTT) technique, which approaches a full-split design and intends to augment soft tissues coronal to the gingival margin. It was shown step-by-step, and the results were presented in a case series. Healthy individuals (non-diabetics) and non-smokers with gingival recession (GR) type 1 or 2 (RT1 or RT2) were included. After evaluation, prophylaxis was performed 14 days before the surgical procedure. During the surgical appointment, one or two vertical incision(s) on the mucosa (around 1-2 mm apical to the MGJ), lateral to the papilla base, was/were performed after anesthesia. Initially, there was a partial incision to detach the mucosa of the muscles (split design). It was permitted (but not mandatory) to perform intrasulcular incisions. Through the vertical incision, internally, subperiosteal access from the MGJ toward the gingival margin (coronally) was performed to create a full-thickness tunnel. Then, communication from the vertical incision with the gingival sulcus and the papilla base occurred, keeping the papilla tip intact. A connective tissue graft was harvested and inserted through the linear incision or intrasulcularly. There were interrupted sutures. An adjunctive material may be applied (e.g., Endogain). The root coverage was measured using a periodontal probe and considered fully covered when the gingival margin was 1 mm coronal to the cementum-enamel junction (CEJ). Nine healthy individuals (seven females and two males) aged 19 and 43 were enrolled. They were treated following the MiTT steps. Four cases had a single GR; two patients had two teeth involved; and three others had three or four GR. There were seven cases of RT1 and two RT2. All RT1 cases achieved 100% RC, while the mean RC obtained for RT2 was around 80%. The MiTT technique can be considered a more straightforward approach for minimally invasive surgical techniques, which is a feasible option to treat RC with a high success rate, predictability, and esthetic preservation. Therefore, there is a technical sensitivity to performing the full-split design procedure.

Effect of green tea extract antioxidant on dentin shear bond strength and resin-tag penetration depth after non-vital bleaching.

Background: 35% Hydrogen peroxide (H 2O 2) as an active material for internal bleaching can produce free radicals that can affect resin tag penetration into the dentinal tubules. Application of 10% and 35% green tea (GT) extract as an antioxidant after 2 minutes are expected to remove free radical residues and increase dentin shear bond strength and resin tags penetration depth after non-vital bleaching. Methods: 30 extracted healthy human premolars were cut horizontally 2 mm from the Cemento Enamel Junction margin to the crown part, then cut in a mesio-distal direction into two parts. The specimens were divided into five groups: normal dentin, post bleaching dentin, delayed 2 weeks, 10% GT, and 35% GT group. Non-vital walking bleach with 35% H 2O 2 gel was done to all groups except control group. Soon after, 10% and 35% GT extract gel were applied on dentin for 2 minutes, then the specimens were rinsed-off with aquabidest for 2 minutes and dried. All specimens were etched and bonded with an etch-and-rinse adhesive system and filled with resin composite. The shear bond strength assessment was carried out using a Universal Testing Machine (UTM) with a cross-head speed of 0.5 mm/minute. Confocal laser scanning microscopy (CLSM) with a wavelength of 560 nm and a lens magnification of 40x was used to analyze the resin tag penetration. Data were analyzed by one way ANOVA and t-test. Results: There was a significant difference in resin tag penetration depth and shear bond strength between applying 10% and 35% GT extract (p < 0.05). The 35% GT extract group resulted in a significantly longer resin tag penetration than the 10% GT extract group. Conclusions: The application of 35% GT extract is more effective than 10% GT extract as an antioxidant for increasing the shear bond strength of composite resin after internal bleaching.

Morphological and morphometric characteristics of labial-cervical-vertical groove in upper central incisor

The labial-cervical-vertical groove (LCVG) is a developmental dental anomaly that may be present in the maxillary central incisors (UCI) which can affect periodontal health, facilitate the occurrence cervical decay, and compromise the aesthetics of the gingival contour. A LCVG can present different magnitudes and, when severe, it can impact the prognosis of the affected tooth. Objective: The objective of this study was to investigate the prevalence, extent, and depth of labial-cervical-vertical groove (LCVG) in maxillary central incisors (UCI) from the Human Tooth Bank of Rio de Janeiro State University Dental School, aiming to provide a better understanding of this anomaly and thus to contribute to an accurate differential diagnosis and appropriate dental planning. Material and methods: Ninety-seven dental elements, belonging to the Human Tooth Bank of Rio de Janeiro State University Dental School, were inspected, for presence of LCVG. For analysis of this morphological alteration, the following measurements were registered in millimeters: the total length (measured from the coronal to the apical limits of the defect); its extension in the crown (measured from the defect’s coronal limit to the cementum enamel junction (CEJ)); its extension in the root (measured from the defect’s apical limit to the CEJ) and depth (measurement of the groove’s invagination toward the root canal) of LCVG in each tooth. Results: The prevalence of LCVG in our sample was 7.21%. The average measures observed for the LCVG were: 6.43 (± 1.81) mm of total of length, 2.86 (± 1.68) mm of extension in the root; 3.57 (± 0.98) mm of extension in the crown; and &lt;1 to 1mm of depth. Conclusion: These findings contribute with knowledge on of the detail, of extent and depth of LCVG in UCI, providing the clinician with information that can favor diagnosis and maintenance of teeth with this anomaly.

Биохимическое и морфологическое обоснование соединительнотканной гипотезы прорезывания нижних третьих моляров

Studying the mechanism underlying tooth eruption is an important and promising area due to the increased incidence of the diseases associated with tooth eruption abnormalities or difficulties that can result in purulent and septic complications. The study was aimed to explore variability and structural features of the hard tissue mineral component and organic matrix in mandibular third molars being at different stages of tooth eruption. Microscopic examination and biochemical testing of the enamel, dentin, and dentin–enamel junction of the study participants’ (n = 67; females aged 14–36) mandibular third molars were performed by scanning electron microscopy and Fourier transform infrared (FT-IR) spectroscopy. The association of the tooth eruption stage with the hard tissue structural features, such as the degree of mineralization and the size of dentinal tubules, orientation and size of the enamel prisms, was revealed. There were significant differences in the mandibular third molar hard tissue water content, which was demonstrated by metabolic processes and maturation rate (p &lt; 0.05). According to the IR spectroscopy data, intensity of the collagen absorption bands in the enamel increases with age, while in dentin it decreases (1202, 1249, and 1342 cm–1). Furthermore the combination of the reduced intensity of the 1202 cm–1 band with the increase in the 1342 cm–1 dentin–enamel junction band confirms the important role it plays as a link between the enamel and dentin due to its metabolic, shock-absorbing, protective, and nutritional functions. The findings demonstrate significant changes in the wrapping and orientation of the collagen fibrils and fibers in the hard tissue, which affect primary spatial orientation and mandibular dental topography.

Noninvasive diagnostic method using optical coherence tomography detected a vulnerable dentin enamel junction created by phosphoric acid etching.

To investigate the influence of phosphoric acid etching on the dentin enamel junction (DEJ) using optical coherence tomography (OCT). Human teeth were assigned to four groups: 1. control, no additional treatment (CT); 2. The primer of "SE Bond2" was applied (SE), 3. "Enamel Conditioner" was applied (EC), 4. "K-etchant syringe" was applied (KE). After treatment, the DEJ was observed using a laser microscope (CLSM), OCT, and scanning electron microscopy (SEM). Additionally, an ultimate tensile strength (UTS) test at the DEJ was performed. No cracks were observed by CLSM. In contrast, cracks were observed all samples by SEM. Additionally, OCT revealed a white line along the DEJ in all KE specimens and some EC specimens. The UTS test showed a significant difference between CT and KE. This study found that phosphoric acid etching may cause excessive demineralization and weaken the DEJ. This fragility was observed using a non-invasive diagnostic method using OCT.

Assessment of the Peri-Implant Conditions for the Primary and the Repeated Abutment Placements: An Original Research.

Recurrent abutment substitutions may physically irritate the mucosal (soft tissue) barrier, which may cause additional toxic irritants and germs to enter the mucosal implant barrier and weaken the tissues surrounding implant. The creation of a "definitive abutment" may lessen the likelihood of tissue losses around the implant. Determining the characters of the peri-implant tissue after the placement of the definitive abutments and multiple abutment replacement was the goal of this study. Forty missing teeth were replaced with implants in matched subjects. Parameters assessed were "distance of cement enamel junction to alveolar crest and distance of CEJ to gingival margin; bleeding on probing, Sulcus probing depth, and peri-implant marginal bone loss." Subjects were randomly assigned for the two groups of intervention. All the measurements were documented at designated timelines and compared for the statistical variance where P < 0.05 was considered as significant. In the control and test groups, the peri-implant marginal bone level rose from baseline to 3 months. There were no appreciable differences between the CEJ-AC and CEJ-GM groups when the clinical and radiographic parameters of each group were evaluated. Throughout all of the time points, the soft tissue borders in both groups remained comparably steady. The study's findings suggest that using implants with definite abutments is more advantageous for obtaining better maintenance in terms of the health of the tissues that surround the implants.

Estimated Age Calculation with Tooth Coronal Index (TCI) Method Using Orthopanthomography in Malang City Population

Age estimation is an important aspect in forensics because it plays a role in determining individual identity. In cases of forensic identification of bodies that are difficult to identify visually or in poor condition, radiography is the choice of non-invasive method that can be used for age estimation, one of which is panoramic radiography. The Tooth Coronal Index (TCI) method is one method that can be used to identify a person's biological age through panoramic radiography. The purpose of this study was to compare the chronological age with the biological age obtained from the measurement of the TCI method on the mandibular premolars using panoramic radiography in the Malang City population. TCI measurement was done by measuring the height of the pulp chamber (Coronal Height) and the height of the crown of the tooth (Coronal Pulp Cavity Height) vertically from the Cemento Enamel Junction (CEJ) on the mandibular premolars. Then the value is entered in the regression equation that has been determined to obtain an estimate of biological age. Then, the results of the estimated biological age are compared with their chronological age. At last, the difference between biological and chronological age is calculated to determine the approximate age. The mean difference between chronological age and biological age was ± 1.32 years and there is no significant difference between the biological age and the chronological age (p value 0.11). TCI method on the mandibular premolars using panoramic radiography can be used to estimate age in Malang City Population.

Effect of green tea extract antioxidant on dentin shear bond strength and resin-tag penetration depth after non-vital bleaching

Background: 35% Hydrogen peroxide (H2O2) as an active material for internal bleaching can produce free radicals that can affect resin tag penetration into the dentinal tubules. Application of 10% and 35% green tea (GT) extract as an antioxidant after 2 minutes are expected to remove free radical residues and increase dentin shear bond strength and resin tags penetration depth after non-vital bleaching. Methods: 30 extracted healthy human premolars were cut horizontally 2 mm from the Cemento Enamel Junction margin to the crown part, then cut in a mesio-distal direction into two parts. The specimens were divided into five groups: normal dentin, post bleaching dentin, delayed 2 weeks, 10% GT, and 35% GT group. Non-vital walking bleach with 35% H2O2 gel was done to all groups except control group. Soon after, 10% and 35% GT extract gel were applied on dentin for 2 minutes, then the specimens were rinsed-off with aquabidest for 2 minutes and dried. All specimens were etched and bonded with an etch-and-rinse adhesive system and filled with resin composite. The shear bond strength assessment was carried out using a Universal Testing Machine (UTM) with a cross-head speed of 0.5 mm/minute. Confocal laser scanning microscopy (CLSM) with a wavelength of 560 nm and a lens magnification of 40x was used to analyze the resin tag penetration. Data were analyzed by one way ANOVA and t-test. Results: There was a significant difference in resin tag penetration depth and shear bond strength between applying 10% and 35% GT extract (p &lt; 0.05). The 35% GT extract group resulted in a significantly longer resin tag penetration than the 10% GT extract group. Conclusions: The application of 35% GT extract is more effective than 10% GT extract as an antioxidant for increasing the shear bond strength of composite resin after internal bleaching.