The effect of ferrule and core material on fracture resistance of endodontically treated anterior teeth restored with ceramic crowns after artificial aging.

OBJECTIVES: To assess the influence of ferrule and core type on the fracture strength of endodontically treated anterior teeth (ETAT) and identify the failure mode type and distribution across different core types and ferrule conditions. METHODS: Sixty extracted human central incisors were endodontically treated, decoronated and divided into two main groups (F=with ferrule, NF=no ferrule). Each main group was further subdivided into three subgroups according to the core material used: direct composite cores (DC), Ribbond fibre-reinforced composite cores (RIB-DC), and glass fibre post (GFP) with direct composite cores (GFP-DC). All specimens received E.max crowns and underwent thermal cycling and cyclic loading. Subsequently, the fracture resistance was tested with static loads applied to the crown restoration. Two-Way ANOVA and Chi square tests identified significant differences among the groups (p < 0.05). RESULTS: The means and standard deviations (SD) of fracture loads in Newtons (N) for specimens in the F subgroups were RIB-DC: 465.0 (104.20), GFP-DC: 367.6 (79.59), DC: 275.8 (68.48), and in NF subgroups were RIB-DC: 110.8 (24.33), GFP-DC: 95.6 (25.47), DC: 67.4 (7.46). Specimens with ferrule yielded significantly higher fracture loads than those without ferrule (p = 0.0054). In the F groups, fracture loads of specimens with RIB-DC cores were significantly higher than those with GFP-DC (p = 0.0019) and those with DC (p = 0.0001). Moreover, fracture loads for the GFP-DC were significantly higher than those for the DC (p = 0.0026). The GFP-DC specimens showed the highest incidence of catastrophic failures (p = 0.0420). CONCLUSIONS: Using fibre-reinforced composite (FRC) cores significantly increased fracture resistance in ETAT with ferrule. The failure modes repairable and possibly repairable were dominant in most specimens. CLINICAL SIGNIFICANCE: When restoring ETAT with insufficient coronal tooth structure, preserving 2 mm of tooth structure ferrule and preparing cores with FRC can increase fracture resistance and reduce the incidence of non-repairable catastrophic fractures of teeth.

Effects of silane coupling treatment on the clinical performance of direct repaired resin-based composite (RBC) restorations with or without prior surface sandblasting: A randomized controlled trial.

OBJECTIVE: To evaluate the effects, of using silane coupling agent within the procedures of repairing old composite restorations with or without sandblasting their surfaces, on the clinical performance of repaired composite restorations. METHODS: The study involved repairing 130 Class I and II defective composite restorations. After recurrent caries removal, the repair process included etching with 37 % phosphoric acid, Adper Single Bond 2 application for bonding and Filtek Z250 composite for restoring all defects. The restoration surfaces were subjected to one of the following additional surface treatments within the repair process: Control: No additional treatment; the Silane-Adhesive treatment: A separate step involved the application of a silane coupling agent after acid etching; and the Sandblast-Silane-Adhesive treatment: included intra-oral sandblasting of old composite surfaces followed by silane application. Two calibrated examiners evaluated all repaired restorations according to a modified USPHS criteria after 6 months. Comparisons of the clinical performance between the treatment groups were made using Chi-square test, while responses to cold tests before and after repair treatment were made using Wilcoxon's Signed Rank's (α = 0.05). RESULTS: Of 130 cases, only 116 cases turned up for evaluation. The primary reasons for composite repair were recurrent caries and anatomical deficiencies. No statistically significant differences were found between the groups for all clinical criteria (p > 0.05). The control group experienced one total and two partial retention losses. CONCLUSIONS: The application of a silane coupling agent, with or without intra-oral sandblasting, demonstrated no improvement on the clinical performance of repaired posterior composites after 6-months. CLINICAL SIGNIFICANCE: Surface treatment of defective composite restorations using silane with intra-oral sandblasting within their repair process offered marginal improvement in their clinical performance over conventional etching technique, but insignificantly so. Repair reduced exaggerated cold test responses and eliminated POS within 6-months. Repair reduces cold sensitivity and promotes restoration longevity. This clinical trial was registered at ClinicalTrials.gov with the registration number NCT06005571.

Two-body wear of different ceramic materials opposed to zirconia ceramic.

STATEMENT OF PROBLEM: Little is known about the wear behavior of ceramics opposed to unveneered zirconia and whether wear varies according to microstructure, surface toughness, and flexural strength of the ceramics. PURPOSE: The purpose of this study was to evaluate the 2-body wear resistance of 5 ceramics opposing unveneered zirconia ceramic. MATERIAL AND METHODS: Yttrium-stabilized zirconia, lithium disilicate glass ceramic, leucite-reinforced glass ceramic, fluorapatite glass ceramic, and nanofluorapatite glass ceramic specimens (n=8) were tested against standardized zirconia balls. Wear tests were performed in a dual-axis mastication simulator. Wear resistance was calculated by measuring the vertical and volumetric substance loss using a laser scanner. Specimen surfaces were evaluated at x50 and x500 magnification using SEM. Data were statistically analyzed using 1-way ANOVA and Fisher's exact test (alpha=.05). RESULTS: Zirconia specimens demonstrated significantly lower vertical and volumetric loss than other ceramics (P<.05). The wear of fluorapatite and nanofluorapatite glass ceramics was significantly greater than that of leucite-reinforced and lithium disilicate glass ceramics (P<.05). SEM images showed no cracks or flaws in the zirconia and leucite-reinforced glass-ceramic specimens, indicating a mixture of attritional and adhesive wear. Other ceramic specimens exhibited cracks and chipped particle spaces which were consistent with fatigue wear. Zirconia demonstrated the lowest vertical and volumetric wear values. Leucite-reinforced and lithium disilicate glass ceramics demonstrated nonsignificant differences in volumetric wear, but these values were significantly lower than those observed for nanofluorapatite and fluorapatite glass ceramics (P<.05). CONCLUSIONS: Wear varied according to the structure of the ceramic tested. Wear was of the fatigue type, and was significantly lowest in the zirconia specimens tested.

Clinical assessments and patient evaluations of the esthetic quality of maxillary anterior restorations.

PURPOSE: Dental esthetics has increasingly become an important and rewarding discipline in dentistry as patients have begun to request anterior restorations of high esthetic quality. Clinicians must be prepared to meet the esthetic demands and high expectations of their patients. Different variables may influence the esthetic quality of restorations. Quality evaluations may vary with clinical or patient assessments. This study attempted to assess the esthetic quality of maxillary anterior restorations in order to determine the percentage of restorations with satisfactory quality, examine variables affecting esthetic quality, and make comparisons between agreements and disagreements in clinical and patient evaluations. MATERIALS AND METHODS: Restorations in patients attending different dental clinics in Irbid, Jordan were examined. Clinicians compared the color and shape of the restorations with those of a natural tooth using Ryge criteria, and patients evaluated the same parameters and the surface texture using a Visual Analogue Scale (VAS). Evaluations ranked the quality as good, satisfactory, or poor. RESULTS: The percentage of esthetic complaints was 32.4%, whereas the percentage of satisfactory restorations revealed was 43.8% and 67.6% by clinical and patient assessments, respectively. Restorations yielded significantly better scores on both evaluations when they were prepared by dental students, made in the Dental Teaching Centre (DTC), or were less than one year old. The number of agreements between clinical and patient rankings was significantly less than disagreements. CONCLUSIONS: There were statistically significant disagreements on the esthetic quality between clinicians and patients. Age, gender, practice sector, qualification of the operator, type, and longevity of restoration significantly affected the assessments.

Effect of dentin conditioning on retention of airborne-particle-abraded, adhesively luted glass fiber-reinforced resin posts.

STATEMENT OF PROBLEM: The smear layer covering root canal dentin as a result of post space preparation procedures may negatively affect the retention of adhesively cemented glass fiber-reinforced resin posts. PURPOSE: The purpose of this study was to evaluate the retention of airborne-particle-abraded glass fiber posts luted with 3 different bonding systems after conditioning the canal dentin with acidic conditioning methods. MATERIAL AND METHODS: Post spaces were prepared in 6 groups of 8 endodontically treated single-rooted teeth. Glass fiber-reinforced resin posts were airborne-particle abraded and luted after etching the canal dentin with phosphoric acid and/or applying XP Bond, Clearfil New Bond, or ED Primer. The groups with their respective etching time, primer, and cement combinations were as follows: XP15: 15 seconds of phosphoric acid treatment, XP Bond and Calibra; XP30: 30 seconds of phosphoric acid treatment, XP Bond and Calibra; NB15: 15 seconds of phosphoric acid treatment, Clearfil New Bond and Panavia 21; NB30: 30 seconds of phosphoric acid treatment, Clearfil New Bond and Panavia 21; ED: ED Primer only and Panavia 21; ED15: 15 seconds phosphoric acid treatment, ED Primer and Panavia 21. Specimens were stored in water for 30 days and subjected to simulated aging conditions. Post retention was measured in tension at a crosshead speed of 2 mm/min. Data were analyzed using Mann-Whitney and Kruskal-Wallis tests followed by post hoc comparisons using Langley method (alpha =.05). The dislodged posts and canals were examined microscopically at x8 and x20 magnification to evaluate the mode of failure. RESULTS: For each group, the mean (SD) retention in N was: XP15: 376.8 (39); XP30: 305.5 (27); NB15: 370.3 (31); NB30: 297.6 (52); ED: 301.6 (43); ED15: 373.8 (46). The retention values of ED15, NB15, and XP15 were significantly higher than those of ED, NB30, and XP30 groups, respectively. Microscopic evaluation demonstrated that the failure mode was primarily mixed. CONCLUSIONS: Luting posts with Panavia 21 or Calibra after etching the dentin with phosphoric acid for 15 seconds produced significantly higher retention values than treating dentin for 30 seconds or with ED Primer, only.

The prevalence and pattern of hypodontia of the permanent teeth and crown size and shape deformity affecting upper lateral incisors in a sample of Jordanian dental patients.

OBJECTIVE: The aim of this study was to determine the prevalence and pattern of hypodontia and the extent of congenital malformation in the permanent teeth of a sample of Jordanian adults. MATERIAL AND METHODS: Clinical examinations were carried out on 1045 dental patients aged 16 to 45 years to record any congenital absence of teeth except 3rd molars and to note any crown shape or size deformities affecting the upper lateral incisor. The congenital absence of permanent teeth was confirmed by taking complete dental history and orthopantomograms. Impacted teeth and teeth lost as a consequence of extraction or trauma were recorded as present. RESULTS: The prevalence of hypodontia was found to be 5.5% of the sample and the lower second premolar was the most frequently missing tooth. The number of missing upper lateral incisors was significantly higher than that of lower lateral incisors, (p < 0.05). Peg-shaped and reduced size upper lateral incisors were observed in 2.3% and 2.9% of the sample respectively. There were no significant differences according to gender, location of tooth according to arch or side of the jaw and hypodontic pattern. CONCLUSION: The prevalence of hypodontia was 5.5%, that of peg-shaped lateral incisor was 2.3% and that of reduced crown size was 2.9%.

Periodontal diseases and the risk of coronary heart and cerebrovascular diseases: a meta-analysis.

BACKGROUND: This meta-analysis was conducted to examine the relationship between periodontal diseases and coronary heart diseases (CHD) and cerebrovascular diseases (CVD) in observational studies. METHODS: This study was based on seven cohort studies and four studies of other designs that met prestated inclusion criteria. Information on study design, year of publication, study location, sample size, study population, participant characteristics, measurement of risk factors, exposure and outcome measures, matching, controlling for confounders, and risk estimates was abstracted independently by two investigators using a standard protocol. RESULTS: Subjects with periodontitis had an overall adjusted risk of CHD that was 1.15 times (95% confidence interval [CI]: 1.06 to 1.25; P = 0.001) the risk for healthy subjects. There was no heterogeneity among the studies in the overall relative risk estimate (P = 0.472). As compared to healthy subjects, those with periodontitis had an overall adjusted relative risk of CVD of 1.13 (95% CI: 1.01 to 1.27; P = 0.032). CONCLUSIONS: Findings indicated that periodontal infection increases the risk of CHD and CVD. However, this meta-analysis provided no evidence for the existence of strong associations between periodontitis and CHD and CVD. Larger and better-controlled studies involving socially homogeneous populations and measuring specific periodontal pathogens are required to identify a definite association between periodontal disease and the risk of coronary heart disease and cerebrovascular disease.