Available online 4 October 2019
Statement of problem
The definitive impression for a single-unit crown involves many material and technique factors that may affect the success of the crown.
The purpose of this prospective cohort study was to determine whether impression technique (tray selection), impression material, or tissue displacement technique are associated with the clinical acceptability of the crown (CAC).
Material and methods
Dentists in the National Dental Practice-Based Research Network documented details of the preparation, impression, and delivery of 3730 consecutive single-unit crowns. Mixed-effects logistic regression analyses were performed to evaluate associations between impression techniques and materials and the CAC and to assess associations between the presence of a subgingival margin with the displacement technique and the outcome variables CAC and number of impressions required.
Of the 3730 crowns, 3589 (96.2%) were deemed clinically acceptable. A significant difference in the CAC was found with different impression techniques (P<.001) and different impression materials (P<.001). The percentage of the CAC for digital scans was 99.5%, 95.8% for dual-arch trays, 95.2% for quadrant trays, and 94.0% for complete-arch impression trays. Although no statistically significant difference was found in the CAC produced with dual-arch trays without both mesial and distal contacts, crowns fabricated under these conditions were less likely to achieve excellent occlusion. The percentage of the CAC for digital scans was 99.5%, 97.0% for polyether impressions, 95.5% for polyvinyl siloxane impressions, and 90.5% for other impression materials. Accounting for the location of the margin, the use of a dual-cord displacement technique was significantly associated with lower rates of requiring more than 1 impression (P=.015, odds ratio=1.43).
Dual-arch trays produced clinically acceptable crowns; however, if the prepared tooth was unbounded, the occlusal fit was more likely to have been compromised. Digital scans produced a slightly higher rate of CAC than conventional impression materials. The use of a dual-cord technique was associated with a decreased need to remake impressions when the margins were subgingival.
Published online: October 07, 2019
Several strategies have been investigated for achieving successful pulpal anesthesia during endodontic treatment of mandibular molars with symptomatic irreversible pulpitis. However, comprehensive evaluation and identification of the most efficacious and safe intervention are lacking. We aimed to determine this using network meta-analysis.
MEDLINE, Embase, Cochrane Central, CINAHL, and Scopus databases were searched. Study selection and data extraction were performed in duplicate. Eligible randomized controlled trials were meta-analyzed to estimate the treatment effects (odd ratios [ORs]; 95% credible interval (CrI) and surface under the cumulative ranking curve (SUCRA)]. CINeMA software (University of Bern, Bern, Switzerland) was used to assess the quality of results.
Thirty-seven interventions from 46 studies were identified. Compared with the common practice of an inferior alveolar nerve block with 2% lidocaine, a supplemental intraosseous injection was ranked the most efficacious with very low to moderate confidence (2% lidocaine + preoperative nonsteroidal anti-inflammatory drugs [NSAIDs] + acetaminophen [OR = 74; 95% CrI, 15–470; SUCRA = 97%], 2% lidocaine + preoperative NSAIDs [OR = 46; 95% CrI, 8–420; SUCRA = 94%], 2% lidocaine [OR = 33; 95% CrI, 14–80; SUCRA = 93%], 2% lidocaine + preoperative opioids + acetaminophen [OR = 20; 95% CrI, 4.4–98; SUCRA = 86%], and 4% articaine [OR = 20; 95% CrI, 6.3–96; SUCRA = 87%]) followed by supplemental buccal and lingual infiltrations using 4% articaine + preoperative NSAIDs (OR = 18; 95% CrI, 6–56; SUCRA = 86%; very low confidence). No major safety concerns were reported.
Very low- to moderate-quality evidence suggests intraosseous injection using 2% lidocaine with 1:100,000 epinephrine or 4% articaine with 1:100,000 epinephrine or buccal and lingual infiltrations of 4% articaine with 1:100,000 epinephrine are superior strategies to achieve pulpal anesthesia during endodontic treatment of mandibular molars with symptomatic irreversible pulpitis. Preoperative NSAIDs or opioids with or without acetaminophen may increase the efficacy of these injections.
\J. Appl. Oral Sci. vol.27 Bauru 2019 Epub Oct 07, 2019
A randomized, prospective clinical study evaluating effectiveness of a bulk-fill composite resin, a conventional composite resin and a reinforced glass ionomer in Class II cavities: one-year results
Bulk-fill restorative materials such as bulk-fill composite resins and high viscous glass ionomer cements have become very popular materials in operative dentistry because their application is easy and time-saving.
The aim of this clinical study was to evaluate the clinical performance of a highly viscous reinforced glass ionomer material, a bulk-fill composite resin and a micro hybrid composite resin in Class II restorations.
In total, 109 Class II restorations were performed in 54 patients using three different restorative materials: Charisma Smart Composite (CSC); Filtek Bulk Fill Posterior Restorative (FBF); Equia Forte Fil (EF). Single Bond Universal adhesive (3M ESPE, Germany) was used with composite resin restorations. The restorations were evaluated using modified USPHS criteria in terms of retention, color match, marginal discoloration, anatomic form, contact point, marginal adaptation, secondary caries, postoperative sensitivity and surface texture. The data were analyzed using Chi-Square, Fischer’s and McNemar’s tests.
At the end of one year, 103 restorations were followed up. No changes were observed during the first 6 months. At the end of one year, there were small changes in composite restorations (FBF and CSC) but no statistically significant difference was observed between the clinical performances of these materials for all criteria (p>0.05). However, there was a statistically significant difference between EF, FBF and CSC groups in all parameters except marginal discoloration, secondary caries and postoperative sensitivity in one-year evaluation (p<0 .05="" p="">
Bulk-fill composite resins and conventional composite resins showed more successful clinical performance than highly viscous reinforced glass ionomers in Class II cavities.
A new paper was just published in Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology that evaluated the accuracy of The Canary System, Bitewing Radiographs and Cone Beam CT for detecting natural caries under composite restorations in interproximal regions (https://doi.org/10.1016/j.oooo.2019.09.006). This study found that The Canary System was more accurate than Bitewing Radiographs and Cone Beam CT in detecting caries on the gingival floor beneath composite restorations. The sensitivity and specificity data (table on the right) indicates that The Canary System could find 89% of the caries where the other devices found 40% of the lesions.
One of the major reasons for replacing restorations is tooth decay that develops around the edges of the filling. This study found that “Radiographs though valuable in the detection of advanced caries lesions, are less sensitive for early or recurrent lesions under restorations.” The Canary System which does not use ionizing radiation can serve as a sensitive tool in early caries detection.
The findings in this study mirror the findings from other studies done by Dr. Amaechi’s group at the University of Texas at San Antonio. A clinical trial, which was reported at a research conference in 2015, found The Canary System was superior to bitewing radiography for the detection of proximal caries. The Canary System found 92% of the caries while bitewing radiographs found only 67%.
Radiographs including bitewings are commonly used to detect caries at the interproximal or contact areas but they do not reveal enamel white-spot lesions or all recurrent caries around restorations. Approximately 30%–40% mineral loss is necessary before an early enamel caries lesion is visible radiographically and demineralization may not appear radiographically until at least 9 months or longer after initiation.
Finding decay early may allow oral health providers to use various preventive / remineralization products to help stabilize the lesion or re-harden it.
The Canary System, with its unique crystal structure diagnostics, can quantify, image, monitor and record changes in the structure of enamel, dentin and cementum. It can detect caries beneath opaque sealants, around the margins of restorations, around orthodontic brackets and beneath interproximal, occlusal and smooth surfaces.