Enamel Junction Research Articles

Analysis of the Association of Foramen Cecum and Dens in Dente in Maxillary Lateral Incisor.

Objectives The aim of this study was to evaluate the frequency of foramen cecum and dens in dente, and to verify the association of these structures in the maxillary lateral incisor (MLI). Materials and Methods The presence of foramen cecum in the lingual surface of 110 MLI was verified, and the teeth were radiographed to observe the presence of dens in dente, being classified according to the literature. An association study between the presence of foramen cecum and dens in dente was performed using the Cramer’s V and chi-square statistical tests. Results The association was statistically significant between the foramen cecum and the dens in dente. Concomitant presence was observed in 17.27%, being a high rate when compared with the presence of foramen cecum alone (9.09%) or dens in dente alone (8.18%). In addition, type I (minimal invagination, confined to the crown of the tooth and not extending beyond the level of the cementum–enamel junction) was the most frequent (82.14%). Conclusions We emphasize the importance of alerting the dentist to the presence of a foramen cecum on the lingual surface of the MLI, as it is likely that dens in dente is usually of type I. Thus, the foramen cecum is a sign that can assist the dental surgeon in the discovery of dens in dente and clinical conduct to be taken.

EMILIN proteins are novel extracellular constituents of the dentin-pulp complex

Odontoblasts and pulp stroma cells are embedded within supramolecular networks of extracellular matrix (ECM). Fibrillin microfibrils and associated proteins are crucial constituents of these networks, serving as contextual scaffolds to regulate tissue development and homeostasis by providing both structural and mechanical properties and sequestering growth factors of the TGF-β superfamily. EMILIN-1, -2, and -3 are microfibril-associated glycoproteins known to modulate cell behaviour, growth factor activity, and ECM assembly. So far their expression in the various cells of the dentin-pulp complex during development, in the adult stage, and during inflammation has not been investigated. Confocal immunofluorescence microscopy and western blot analysis of developing and adult mouse molars and incisors revealed an abundant presence of EMILINs in the entire dental papilla, at early developmental stages. Later in development the signal intensity for EMILIN-3 decreases, while EMILIN-1 and -2 staining appears to increase in the pre-dentin and in the ECM surrounding odontoblasts. Our data also demonstrate new specific interactions of EMILINs with fibulins in the dentin enamel junction. Interestingly, in dentin caries lesions the signal for EMILIN-3 was significantly increased in inflamed odontoblasts. Overall our findings point for the first time to a role of EMILINs in dentinogenesis, pulp biology, and inflammation.

GINGIVAL BIOTYPE- AN APPRAISAL IN THE ESTHETIC ZONE

The interface between the restoration and the gingival tissue seems to have a great influence on the final outcome of various treatments. Therefore, the aim of this study was to evaluate the correlation between different morphometric parameters with the thickness of buccal gingiva at the cemento- enamel junction. In 60 periodontally healthy subjects, the six maxillary anterior teeth were examined. Clinical parameters included the gingival thickness, crown width/crown length ratio (CW/ CL), gingival width (GW), papillary height and transparency of the periodontal probe through the gingival sulcus (TRAN). A positive correlation was found between the gingival thickness (GT) and the crown width/ crown length (CW/CL) ratio as well as the papillary height (PH). A weak negative correlation was found between the transparency of probe TRAN and gingival width (GW) with the gingival thickness (GT). Thus, crown form (CW/CL) and papillary height are helpful indicators to determine the gingival thickness at the cemento- enamel junction. The transparency of probe method is subjective and cannot be relied upon for clinical application.

Association of subepithelial connective tissue graft and plasma rich-fibrin for treatment of gingival recession – clinical case report with 12 months post-surgical follow-up

Gum is a portion of periodontal tissue that plays an important role in protecting the surface of the teeth. Its migration beyond the boundaries of the cementum enamel junction, exposing the root of the tooth, is called Gingival Recession (GR) which increases susceptibility to root caries, dentin sensitivity, and aesthetic discomfort. Objective: The main goal of this case report is to describe a surgical procedure that combined the technique of subepithelial connective tissue graft and Plasma-rich fibrin for treatment of gingival recession. Case report: A man, 45 years old, leucoderma, attended the Positive University dental clinic complaining that ‘his gum was rising, and his teeth were sensitive’. Clinical buccal examination was performed according to international guidelines for periodontal data collection and was the man was diagnosed with GR in the region comprising the buccal faces of the first right upper molar to the first right premolar. Before surgical procedure, 60 ml of blood Gum is a portion of periodontal tissue that plays an important role in protecting the surface of the teeth. Its migration beyond the boundaries of the cementum enamel junction, exposing the root of the tooth, is called Gingival Recession (GR) which increases susceptibility to root caries, dentin sensitivity, and aesthetic discomfort. Objective: The main goal of this case report is to describe a surgical procedure that combined the technique of subepithelial connective tissue graft and Plasma-rich fibrin for treatment of gingival recession. Case report: A man, 45 years old, leucoderma, attended the Positive University dental clinic complaining that ‘his gum was rising, and his teeth were sensitive’. Clinical buccal examination was performed according to international guidelines for periodontal data collection and was the man was diagnosed with GR in the region comprising the buccal faces of the first right upper molar to the first right premolar. Before surgical procedure, 60 ml of blood

Clinical comparison between Multi-Stranded Wires and Single strand Ribbon wires used for lingual fixed retainers

BackgroundLong-term retention with fixed retainers with a high success rate seems to be a reasonable solution to minimize or prohibit relapse of orthodontic treatment.MethodsTwo hundred sixty patients between 13 and 30 years old were recruited for this study. The 0.0175 stainless steel twisted wire (G&H Orthodontics, USA) was compared with a single-strand ribbon titanium lingual retainer wire (Retainium, Reliance orthodontics, USA) was used. When treatment was completed, the retainers were bonded from canine to canine in the mandibular arch of the participants. In the follow-up visits, the patients were recalled every 3 months during the 24 months. Detachments, the time of debonding, and side effects were recorded. Statistical analysis was performed by a blinded statistician using a statistical package for Social Science (SPSS, Version20). After descriptive statistics, Kaplan-Meier analysis was performed to measure the survival rates of each retainer. P value < 0.05 was considered as significant.ResultsFinally, 138 patients who received twisted wire splint and 112 patients who received ribbon wire were included in the analysis. The average duration of success was about 23 months for twisted wire and ribbon wire, according to the Kaplan-Meier estimates. The analysis showed no significant overall difference between the treatments (p = 0.13). Failure rates in terms of detachments in all groups occurred at the enamel junction, and it was 25 in twisted retainer group (18.1%) and was 10 in ribbon retainer group (8.9%); the Kaplan-Meier analysis test detected a significant difference in the failure rates between the groups (p = 0/006).ConclusionsAlthough the conventional twisted stainless steel wire and single-strand titanium flat metal ribbon wire as fixed orthodontic retainers have the same clinical effects, it was shown that the ribbon wire has less failure in terms of detachments.

Teeth resorption at cement - enamel junction (CEJ) - Microscopy analysis

The cement – enamel junction (CEJ) gains a growing interest in clinical dentistry, due to an increasing number of idiopathic tooth resorption leading to the inevitable loss of permanent dentition. Therefore, in this research study, we investigated healthy and under resorption teeth to verify junctions’ morphology in relation to the resorption process, its initiation, and propagation. Using light and scanning electron microscopy we examined the three types of CEJ: 1) coronal cementum, 2) abutment) and 3) the gap between cementum and enamel. With energy-dispersive X-ray spectroscopy (EDX) we analyzed the Ca and P concentration along the CEJ border. The study indicated the strict correlation between the gap junction and tooth resorption, due to the dentine exposure to the oral environment.

Determination of Position of Mental Foramen on CBCT

Aim: To determine the position of mental foramen based on the height from alveolar crest and lower border of the mandible from CBCT scans. Objective: The purpose of the study is to determine the position of mental foramen based on the height from alveolar crest and lower border of the mandible from CBCT scans. Materials and Method: A total of 50 CBCT scans will be evaluated. The number, size and form of the mental foramen will be recorded and their three dimensional relationship with the mandibular premolars will be observed and noted. The position of each mental foramen relative to bony reference points will be measured and distances from mental foramen to the cement enamel junctions of the mandibular premolars will be measured. Data will be analyzed and results will be determined. Results: The average values were obtained for the distance between the mental foramen and the alveolar crest, mental foramen to the lower border of the mandible the horizontal and vertical dimensions of the mental foramen. All of the individuals has a single mental foramen which was ovoid in shape. The mean horizontal dimensions were (2.70±0.73)mm and (2.73±0.72)mm on the right and left sides respectively. Vertical dimensions were (2.20±0.65)mm and (1.86±0.16)mm respectively on the right and left sides. Mean distances from the mental foramen to alveolar crest and the lower border of the mandible were (11.35±3.92,10.48±2.84) and (9.47±1.48, 9.72±1.38) respectively. Conclusion: The average values obtained from the study help in understanding the anatomy and position of the mental foramen better on CBCT. The detailed information about the relationship between mental foramen and its surrounding structures will facilitate diagnostic and surgical procedures done in the oral and maxillofacial region.

Periodontal Ligament Cell Sheets and RGD-Modified Chitosan Improved Regeneration in the Horizontal Periodontal Defect Model.

Objective The aim of this study was to examine the potential of periodontal ligament (PDL) cells sheet and arginine-glycyl-aspartic acid (RGD)-modified chitosan scaffold for periodontal tissue regeneration in horizontal periodontal defect model. Materials and Methods PDL cell cytotoxicity was tested with 3–[4,5- dimethylthiazol-2yl]–2,5-diphenyl-2H-tetrazolium bromide assay. Cell migration toward the chitosan-based materials was analyzed with trans-well migration assay. Horizontal periodontal defect model was created in four maxillary and mandibular lateral incisors of Macaque nemestrina . Following periodontal therapy, the sites were transplanted with various regenerative materials: (1) chitosan, (2) RGD-modified chitosan, (3) PDL cell sheet with chitosan, (4) PDL cell sheet with RGD-modified chitosan. The periodontal tissue regeneration was evaluated clinically and radiographically. Gingival crevicular fluids were collected each week to evaluate cementum protein-1 (CEMP-1) expression with enzyme-linked immunosorbent assay, while the biopsies were retrieved after 4 weeks for histological and microcomputed tomography evaluation. Statistical Analysis Data was statistically analyzed using GraphPad Prism 6 for MacOS X. Normality was tested using the Shapiro–Wilk normality test. The Kruskal–Wallis test was used to compare the groups. Significance was accepted when p < 0.05. Results Clinical examination revealed more epithelial attachment was formed in the group with PDL cell sheet with RGD-modified chitosan. Similarly, digital subtraction radiography analysis showed higher gray scale, an indication of higher alveolar bone density surrounded the transplanted area, as well as higher CEMP-1 protein expression in this group. The incorporation of RGD peptide to chitosan scaffold in the group with or without PDL cells sheet reduced the distance of cement–enamel junction to the alveolar bone crest; hence, more periodontal tissue formed. Conclusions Horizontal periodontal defect model could be successfully created in M. nemestrina model. Combination of PDL cell sheet and RGD-modified chitosan resulted in the higher potential for periodontal tissue regeneration. The results of this study highlight the PDL cell sheet and RGD-modified chitosan as a promising approach for future clinical use in periodontal regeneration.

Influence of cervical preflaring and root canal preparation on the fracture resistance of endodontically treated teeth

BackgroundEvaluate the fracture resistance of endodontically treated teeth after cervical preflaring and root canal preparation and to assess the volume of the root canal and the amount of remaining root dentin before and after cervical preflaring.MethodsForty-four mandibular incisors were selected using micro-CT scanning and distributed into 4 groups (n = 11) according to the instrument used for cervical preflaring: control group - no cervical preflaring; Gates Glidden – burs size #2 and #3; WXN – 25.07 Navigator instrument; and Easy – 25.08 ProDesign S instrument. Coronal opening was performed, and the canals were prepared with Wave One Gold Primary and filled with an epoxy-resin based sealer and gutta-percha cones. Micro-CT scans were performed before and after root canal instrumentation. All images were reconstructed and assessed for the thickness of mesial and distal root dentin at 3 mm and 5 mm from the cement -enamel junction and for the volume of cervical portion of the canal after preparation. Fracture resistance test was performed applying compressive loads at a crosshead speed of 0.5 mm/min, applied on the palatal aspect of specimens at 135° along the long axis of the tooth. The data were analyzed using ANOVA and Tukey’s test (P = .05).ResultsCervical preflaring and canal preparation reduced the dentin thickness (P < .05) and increased the canal volume (P < .05) in all groups at 3 mm an 5 mm. Cervical preflaring with Gates Gliden burs reduced the fracture resistance of endodontically treated teeth (P < .05).ConclusionsAll instruments reduced the dentin thickness and increased the canal volume in the cervical at 3 mm and 5 mm. Gates Glidden reduced fracture resistance of mandibular incisors submitted to cervical preflaring, whereas NiTi instruments did not.Clinical relevanceCervical preflaring assumes particular importance previously to the root canal preparation because it minimizes the occurrence of operative accidents, and permits more accurate determination of working length and the apical diameter.

The Effect of Silver, Zinc Oxide, and Titanium Dioxide Nanoparticles Used as Final Irrigation Solutions on the Fracture Resistance of Root-Filled Teeth.

AimThis study was conducted to evaluate the effect of three nanoparticle solutions used as final root canal irrigants on the fracture resistance of endodontically treated roots.Materials and MethodsSixty intact single-rooted premolar teeth were used after removing the crowns below the cementum–enamel junction to standardize the length of the remaining roots to 13 mm. After instrumenting the roots using ProTaper Universal rotary instruments up to size F4, the roots were randomly divided into six groups (n=10) according to the final irrigating solutions: Group 1: normal saline; Group 2: 2% chlorhexidine (CHX); Group 3: 17% EDTA+2.5% NaOCl; Group 4: 17% EDTA+0.1% silver nanoparticle (SNP) solution; Group 5: 17% EDTA+0.1% titanium dioxide nanoparticle (TNP) solution; Group 6: 17% EDTA+0.1% zinc oxide nanoparticle (ZNP) solution. After filling the root canals with gutta-percha and AH Plus sealer, the fracture resistance (FR) values were measured. The data were subjected to the one-way analysis of variance and the Tamhane post hoc test (p=0.05).ResultsEDTA + NaOCl had the lowest FR value, followed by normal saline and CHX (p values < 0.05). No significant difference was found between the FR of roots irrigated with CHX and normal saline (p > 0.05). The application of nanoparticles (SNP, TNP, and ZNP) was associated with a significantly greater FR than that of other irrigation solutions (p values < 0.05).ConclusionThe final irrigation of root canals with nanoparticles enhanced the fracture resistance of the endodontically treated roots. The lowest FR value was observed for NaOCl.

Anisotropic ultimate strength and microscopic fracture patterns during tensile testing in the dentin-enamel junction region.

The dentin-enamel junction (DEJ), which is the interface between the outer tooth enamel and the underlying dentin, has unique biomechanical properties that allow the two different materials to function together without fracture. The aim of this study was to investigate the anisotropic ultimate tensile strength of the DEJ. Twenty dumbbell-shaped samples were prepared from 10 extracted human molar teeth for tensile strength testing. The maximum tensile forces at fracture were measured in the direction parallel (10 samples) and perpendicular (10 samples) to the DEJ. The mean tensile strength of the samples was significantly higher under parallel forces (30.9±3.3 MPa) than under perpendicular forces (20.6±4.8 MPa; p<0.05). Our findings confirm the structural anisotropy of the DEJ.

Long-term stability of retreated defective restorations in patients with vertical food impaction.

Background:Vertical food impaction (VFI) is a common complaint among patients receiving interproximal restorations. However, there is a gap in the literature regarding outcomes of treating defective restorations with VFI. This study sought to determine 10-year stability of retreated defective restorations in patients diagnosed with VFI.Materials and Methods:A total of 150 teeth (75 pair), in 38 patients comprised our study population. All the participants had been diagnosed with VFI due to faulty restorations and treated by means of redoing the restoration to build a stable contact in at least one restored tooth. The criteria for building an optimum dental contact were defined. Demographic characteristics, date and frequency of redoing the restoration, type and material of restoration, number of restored surfaces, occlusal intercuspal relationship, missing adjacent and/or opposing teeth, cemento enamel junction to alveolar crest distance, recurrence of VFI symptoms, recurrent caries, and periapical pathology as well as periodontal variables were recorded.Results:Kaplan–Meier estimator revealed that the mean ± standard deviation of 1, 3, 5, and 10-year stability of reconstructed contacts was 89/2% ± 3/6%, 79/2% ± 5%, 70/7% ± 0/06%, and 66/3% ± 7/1%, respectively. The overall cumulative stability rate was 74/4%. Further analysis predicted that over a 12-year period, restored contacts were stable for 8.86 ± 0.6 years. Cox regression model indicated that having cusp to marginal ridge occlusal relationship (95% confidence interval [CI] for hazard risk (HR) = 1/1–13/9, HR = 3/93), and being over 40 years of age (95% CI for HR = 0/88–17/66, HR = 3/95) were major determinants of contact stability.Conclusions:Long-term stability of retreated and restructured tooth contacts with a history of VFI was 66%–89% in this specific sample.

Microscopic analysis of the cemento enamel junction of human dentition

Microscopic analysis of the cemento enamel junction of human dentition

Fracture resistance, failure mode and stress concentration in a modified endocrown design

Purpose The purpose of this study was to assess fracture resistance, failure mode and stress concentration of a modified endocrown preparation design, under axial and lateral forces. Materials and Methods Forty lower molars were divided into two groups (n = 20) and were restored with lithium disilicate glass-ceramic endocrowns following 2 preparation designs: Conventional, with circumferential butt margin 2 mm above the cemento–enamel junction; and Modified, by adding 2 grooves on the mesial side of the vestibular dentinal wall and on the distal side of the lingual dentinal wall. After cementation and thermomechanical cycling loading, half of the samples (n = 10) from each group were loaded axially and the other half (n = 10) was loaded laterally. Fracture resistance and failure modes were observed and the finite element analysis (FEA) was used to identify the stress concentration. Two-way ANOVA and Chi-square tests (α = 0.05) were used for in vitro data analyzes. Results Fracture resistance showed a statistically significant difference between conventional and modified preparations (p < .001), and between axial and lateral loadings (p < .001). Conventional preparation recorded 2914 N under axial loading and 1516 N under lateral loading, while modified preparation recorded 3329 N under axial loading and 1871 N under lateral loading. FEA showed that retention grooves have reduced the stress concentration under both loads for the tooth and the restoration. Conclusion Modified endocrown design showed higher fracture resistance than conventional endocrown. Lateral loading displayed a high percentage of severe fracture but under higher load to failure than the values reported for normal masticatory forces.

Effect of Apical Root Canal Perforation Size on Push-out Bond Strength of Glass Fiber Dowels

To evaluate in vitro effect of apical root canal perforation size on push-out bond strength of glass fiber dowels cemented to sound or perforated root canals using two different adhesive systems. A total of 120 human-extracted intact upper central incisors were selected. Teeth were sectioned 3 mm coronal to cement enamel junction, and the remaining root received endodontic root canal therapy. The roots were divided into two experimental groups according to the root condition: either sound (n = 40) or apically perforated (n = 80). Dowel spaces were prepared for all specimens to a depth of 10 mm. Roots were restored with glass fiber dowels. The experimental group was further subdivided into four subgroups (n = 20) according to the adhesive system used and apical perforation size: group I, perforated root 2 mm apically, dowel cemented using total-etch adhesive cement; group II, perforated root 2 mm apically, dowel cemented using self-etch adhesive cement; group III, perforated root 4 mm apically, dowel cemented using total-etch adhesive cement; and group IV, perforated root 4 mm apically, dowel cemented using self-etch adhesive cement. The control group, sound root, was divided into two subgroups: group I, sound root, dowel cemented using total-etch adhesive cement, and group II, sound root, dowel cemented using self-etch or total-etch adhesive cement. Each root was then cut horizontally, and root segments were prepared to be tested. The bond strength between dowel and dentin was measured with universal testing machine using a push-out test. The two-way analysis of variance (ANOVA) was used to analyze the data and post hoc Tukey's test (α = 0.05). Root canal perforation and the type of adhesive system used resulted in significant differences in push-out bond strength (p < 0.05). Regardless of root canal perforation size, glass fiber dowels in normal root canals had significantly higher mean bond strength values (9.2 ± 1.4 MPa) compared with perforated root canals (6.1 ± 1.4 MPa). Also, self-etch protocol had significantly higher mean bond strength values (9.1 ± 1.3 MPa) compared with total-etch protocol (6.2 ± 2.1 MPa). The apical root perforation size caused a direct effect on the bond strength of the glass fiber dowels cemented to dentin by reducing the bond strength values to the root dentin regardless of the adhesive system used. Prior to perforation repair, dentist or endodontist should evaluate the perforation size to predict the treatment outcome.

A Cone-Beam Computed Tomographic Study of Alveolar Bone Morphology in Patients With Unilateral Cleft Lip and Palate.

To evaluate the bony support around the teeth adjacent to the unilateral cleft lip and palate (ULCLP) using cone-beam computed tomography. Cone-beam computed tomographies of 48 cleft-adjacent teeth (28 anterior and 20 posterior to the cleft) and 48 noncleft control teeth were evaluated. The alveolar bone thickness at 3 and 6 mm apical to the cement-enamel junction (CEJ), the distance between the alveolar crest and CEJ (Alv-CEJ), and the presence of fenestration were assessed in buccal, palatal, and proximal surfaces. The alveolar bone on the buccal and palatal sides of the teeth anterior to the cleft was significantly thinner than the noncleft teeth (all P < .05). The Alv-CEJ was significantly greater on the buccal and distal surfaces of the teeth anterior to the cleft (P < .001 and P = .010, respectively) and on the palatal and mesial surfaces of the teeth posterior to the cleft (P = .024 and P = .003, respectively) when compared to the noncleft teeth. The frequency of reduced alveolar bone height (>2 mm) was higher than noncleft side for buccal and distal sides of the teeth anterior to the cleft (P = .016 and .006, respectively) and the buccal and mesial sides of the teeth posterior to the cleft (P = .008 and <.001, respectively). The teeth anterior to the cleft had a higher prevalence of fenestration (P = .004). Reduced alveolar bone height is more common in the cleft side compared to the control side. The teeth anterior to the ULCLP have thinner alveolar bone support and higher frequency of fenestration.

MULTIPLE GINGIVAL RECESSION COVERAGE TREATED WITH VISTA TECHNIQUE USING ACELLULAR DERMAL MATRIX (ADM) COMBINED WITH PLATELET RICH FIBRIN (PRF): A CASE REPORT

Background: Gingival recession is an exposure of the root surface due to migration of the marginal periodontal tissues apical to the cemento enamel junction. There are so many root coverage procedures, among these techniques, VISTA technique combined with ADM and PRF offers minimally invasive approach.Case Management: A-40-year-old male visited Periodontics Clinic of DentalHospital Airlangga University with the chief complaint of poor aesthetic resulting from exposed root surfaces in upper right front region of the jaw. Root coverage by VISTA technique using ADM combined with PRF was planned to this case.Discussion: The minimal invasive VISTA technique approach, combined with ADMand PRF has a number of advantages for successful treatment of multiple recession defects. VISTA technique was used because it can maintain better blood supply and maintain critical papillary integrity. ADM works like an autogenous graft by providing a bioactive matrix consisting of collagen, elastin, blood vessel channels, and bioactive protein that support natural revascularization, cell repopulation, and tissue remodeling. Growth factors present in PRF plays a crucial role in hard and soft tissue repair.Conclusion: VISTA technique together with ADM and PRF membrane can besuccessfully used as a treatment method for multiple gingival recessions of Miller’s class I defects

Effect of Bleaching and Ca(OH)2 Dressing on the Bond Strength of Fiberglass Posts to Root Dentine.

Objective The purpose of this study was to evaluate the effect of the intracoronary bleaching and calcium hydroxide (Ca(OH) 2 ) dressing use, on the bond strength (BS) of fiberglass posts to root dentine. Materials and Methods After root canal filling of 40 bovine incisors, a 2-mm thick cervical plug was fabricated 2 mm below the cementum–enamel junction. Seven days later, teeth were randomly distributed into four groups ( n = 10), as follows: G1 no bleaching, followed by immediate post cementation; G2 bleaching and immediate post cementation; G3 bleaching, dressing with Ca(OH) 2 for 7 days, and post cementation; and G4 bleaching, no dressing, and post cementation after 7 days. The roots were transversally cut into 1-mm thick slices to perform the push-out test (0.5 mm/min). Failure modes were assessed under scanning electron microscopy. Statistical Analysis The analysis of variance (two-way ANOVA) was performed, followed by the supplementary Tukey multiple comparison test ( a = 5%). Results No significant difference for BS was observed among groups. Considering the different root thirds, G1 had higher BS values for the cervical third in comparison with the apical one ( p < 0.05). The most frequent failure modes were adhesive between cement/dentine (G1); cohesive at the post (G2 and G3), and mixed (G4). Conclusions The BS of the fiberglass posts to root dentine was not affected by the intracoronary bleaching and the use of Ca(OH) 2 dressing.

Influence of hydrophobic resin coating on micro-tensile bond strength of different adhesives: an in – vitro study

Recently, the etch-and-rinse and self-etching approaches are the two strategies of resin-based adhesive systems to accomplish the bonding to enamel and dentin. The increased amount of solvents and hydrophilic monomers in the adhesive formulations lead to greater amount of residual solvents entrapped in the adhesive layer. Consequently, the resulting polymers will be more susceptible to degradation over time. One of the methods for more durable bond includes the application of an additional layer of a hydrophobic resin coating over the polymerized simplified adhesive. The aim of this in –vitro study was to evaluate the influence of hydrophobic resin coating on micro-tensile bond strength of different adhesives Eighty freshly sound human molars were divided into three main groups according to method of bonding (A), where (A1) represents teeth bonded using Single Bond Universal Adhesive in total each approach, (A2) represents teeth bonded using Single Bond Universal Adhesive in self-etch approach while (A3) represents teeth bonded using Self Etch Future Single Bond DC Bonding System. Each (A) group will be then subdivided into two additional subgroups according to the addition of hydrophobic resin coating into (B1) which stands for teeth with additional hydrophobic resin coating and (B2) which stands for teeth without additional of hydrophobic resin coating. Each (AB) group will be finally subdivided into two smaller subgroups according to the effect of thermocycling, where (T1) denotes the teeth which were thermocycled, and (T2) denotes the teeth which were not thermocycled. The occlusal dentin surface of each molar was prepared on two levels: Superficial level (below the dentino enamel junction by 0.5 mm) and deep level (below the dentino enamel junction by 1.5 mm). For all specimens, after bonding procedures either total etch or self etch, a hydrophobic resin coating was added for the assigned groups. Resin composite was applied; thermo-cycling was done for the assigned groups. Teeth were sectioned into a series of 1 mm thick slabs and microtensile bond strength testing was done. Two representative specimens of each group were selected for Ultramorphological Examination. Mode of application, addition of adhesive layer and thermocycling had a significant effect on bond strength. Within the limits of this study, we concluded that regarding bonding efficacy to enamel and dentine, conventional 3-step etch-and-rinse adhesives are still not surpassed by the newer simplified self etch adhesive systems. Addition of the hydrophobic bonding resin coating improved bonding to dentine especially when used with all-in-one self-etch adhesive systems.

Clinical evaluation of Cention–N and nano hybrid composite resin as a restoration of non-carious cervical lesion

Introduction: Non carious cervical lesion, (NCCL) is the loss of tooth structure at the cemento enamel junction, or CEJ level that is unrelated to dental caries. These lesions can affect plaque retention, tooth sensitivity, structural integrity, caries incidence, and pulpal vitality. Objectives: To compare clinical effectiveness of Cention–N and Nanohybrid composite resin as a restoration of non-carious cervical lesion for gross fracture, marginal integrity & surface texture. Materials and Methods: Total 24 patients having two class V non-carious cervical lesion in the same arch, approximately of same size and shape were selected. Entire study was carried out by two operators. Both teeth were restored, finished and polished by one operator with Cention–N and Tetric N Ceram (Ivoclar – Vivadent) respectively. Evaluation for marginal integrity & surface texture was done by second operator on the same day of restoration. (USPHS, Ryge criteria for direct clinical evaluation). Follow up was done for gross fracture, marginal integrity & surface texture after 1 week, 1 month, 3 month & 6 month. All the data were collected according to USPHS, Ryge Criteria. Statistical analysis was done by chi square test. Results: Cention–N is as effective as Tetric-N-Ceram for gross fracture and marginal integrity till 6 months. But Cention–N showed inferior surface characteristics than Tetric-N-Ceram after 1 week. Conclusion: Cention – N is as effective as Tetric N Ceram for gross fracture and marginal integrity but Cention – N has an inferior surface characteristics than Tetric N Ceram. Keywords: Cention-N, Non-carious cervical lesion, Nano hybrid composite.