Retentive force and dislodgment time variations between three implant overdenture stud attachments in an acidic environment: An in-vitro pilot study.

Introduction: This in-vitro study aimed to evaluate the retentive force and dislodgment time of three stud attachment systems used for mandibular two-implant overdentures by simulating insertion/removal cycles. Materials and methods: From a simulation of a completely edentulous mandible with two parallel implants (Ø4.5 mm internal hex connection) (Zimmer Biomet, Warsaw, IN), 15 resin bases were fabricated and divided into three groups (n = 5 each): OT Equator (Rhein83, Bologna, IT), Locator (Zest Dental Solutions, Escondido, CA) and Locator R-Tx (Zest Dental Solutions, Escondido, CA). Pink inserts underwent 2000 cycles of thermocycling (SD MECHATRONIK GmbH, Feldkirchen-Westerham, Germany) and were soaked in citric acid for 24 days in an incubator. Each base underwent 2000 insertion/removal cycles on the Versa Test testing machine (Mecmesin Ltd., W. Sussex, UK) which was used to measure the retentive force and dislodgment time. The results were analyzed using ANOVA followed by the post-hoc Tukey test, Kruskal-Wallis test, and Pearson correlation coefficient test. A p-value of < 0.05 was considered statistically significant. Results: The retentive force and dislodgment time of the three systems significantly decreased over the cycles (p < 0.05). The Locator R-Tx showed significantly greater retentive force ​​than did the other systems (p < 0.05), except for the last cycles wherein no significant difference was found with the OT Equator (p > 0.05). The OT Equator had the most stable retention over the cycles (p > 0.05; cycle 1500). Conclusion: The three systems showed satisfactory retentive force ​​during the 2000 cycles. The Locator R-Tx demonstrated the best retention, while the OT Equator exhibited the most stable retention over time.

CAD-CAM fabrication of semiprecision LOCATOR-style abutments to correct severely misaligned implants supporting a 4-implant maxillary overdenture.

Implant-supported removable overdentures are a popular treatment option with a favorable impact on a patient's quality of life. A maxillary removable overdenture without palatal coverage should be supported by at least 4 implants uniformly distributed around the arch and connected by either semiprecision attachments or a bar. Optimally these 4 implants should be parallel or have their long axes nearly aligned to facilitate the prosthodontic phase of treatment by allowing the use of standard components. A computer-aided design and computer-aided manufacturing (CAD-CAM) procedure to produce LOCATOR-style attachments (T-L Custom abutments; TruAbutment Inc) to manage the restoration of 4 misaligned implants is described.

A Two-Year Comparative Evaluation of Clinical Performance of a Nanohybrid Composite Resin to a Flowable Composite Resin.

OBJECTIVE: This prospective in vivo study aimed to compare the clinical behavior of a flowable composite resin (Genial Universal Flo, GC) and a nanohybrid universal composite resin (Tetric Evo Ceram, Ivoclar Vivadent) used in Class I and II direct esthetic restorations in posterior teeth. METHODS: A total of 108 Class I and II direct restorations were performed in patients aged between 20 and 60 years. The originality of this study lies in the fact that both materials were placed in pairs, in the same clinical environment (i.e., the same patient and the same type of tooth). The evaluations were performed now of restoration and after 2-weeks, 6-, 12-, and 24-months intervals using clinical examination, clinical photographs, and radiological examination, according to modified USPHS criteria. Statistical analysis was performed using the Fisher exact test and chi-square analysis. RESULTS: At baseline, the universal composite resin showed better esthetic properties such as surface luster, surface staining marginal staining. Both materials regressed significantly over time with no significant difference between groups. CONCLUSIONS: Both flowable and nanohybrid composite resins exhibit acceptable clinical performance. The present 24 months of evaluation of different composites showed that the G-ænial Universal Flo could be an effective esthetic material for posterior restoration. No significant difference between both materials over time concerning surface luster, surface staining, and marginal staining.

Analytical validation of the Target Selector ctDNA platform featuring single copy detection sensitivity for clinically actionable EGFR, BRAF, and KRAS mutations.

BACKGROUND: Personalized medicine requires accurate molecular profiling for targeted therapy decisions. Insufficient tissue yield or tumor heterogeneity frequently limits the correct tissue biomarker determination. As a noninvasive complement to traditional tissue biopsies, liquid biopsies detect and track cancer driver mutations from biofluids (e.g., blood, urine). Here we present the analytical validation of Target Selector™ ctDNA assays capable of single mutant DNA copy detection. METHODS: The Target Selector ctDNA assay applies a patented Switch-Blocker technology to suppress amplification of background (wild-type) WT alleles, while allowing specific amplification of very low frequency mutant alleles. In contrast to allele specific enrichment technologies like ddPCR, one Switch-Blocker inhibits amplification of a DNA target up to 15 bp in length (e.g., one Switch-Blocker covers all KRAS exon 2, codon 12 and 13 variants). Target enrichment is achieved through a quantitative PCR reaction; subsequent DNA sequencing confirms mutation identity. Analytical validation with cancer cell line DNA was conducted by three independent operators using five instruments across five days. RESULTS: A total of 3086 samples were tested on EGFR, BRAF and KRAS Target Selector ctDNA assays, with EGFR WT as a reference. All assays showed >99% analytical sensitivity and specificity. Single mutant copy detection is confirmed by experimental data and theoretical estimates. In the presence of 14000 WT DNA copies, limits of detection were: EGFR Del19, 0.01%; EGFR L858R, 0.02%; EGFR T790M, 0.01%; BRAF V600E, 0.01%; KRAS G12C, 0.02%. Inter- and intra-assay analyses showed r2>0.94, suggesting consistent performance among operational variables. Healthy donor samples (100 tests) showed clinical specificity at >99%. Finally, Target Selector clinical experience data of >2200 patient samples is consistent with published tissue mutation prevalence. CONCLUSIONS: Highly sensitive Target Selector ctDNA assays with single mutant copy detection and limit of detection at 0.02% or better enable accurate molecular profiling vital for disease management.

Predictable Technique to Register Retruded Contact Position (RCP) Using a Disposable Jaw Relation Recording Device.

The dental literature presents various definitions and techniques to describe and register centric relation (CR) or centric occlusion (CO). Briefly reviewing the literature in relation to CR, this article proposes the use of the term retruded contact position (RCP), clinically defined as retruded, unstrained, repeatable position and where the mandibular movements start when a Gothic arch tracing is used. With this clinical definition, a technique can be easily selected that meets all the requirements of such position. The article discusses the use of a jaw recorder that is an intraorally graphic recording device that results in a tracing of mandibular movements in one plane, with the apex of the tracing indicating the retruded, unstrained, and repeatable relationship. The intersection of the arcs produced by the right and left working movement form the apex of the Gothic arch tracing. Several clinical situations using the jaw recorder are described. Clinicians can now quickly and accurately record RCP, balance complete, partial, or implant dentures, and orthopedically reposition the mandible. The technique achieves highly reliable and reproducible results.

CAD/CAM fabricated complete dentures: concepts and clinical methods of obtaining required morphological data.

The clinical impression procedures described in this article provide a method of recording the morphology of the intaglio and cameo surfaces of complete denture bases and also identify muscular and phonetic locations for the prosthetic teeth. When the CAD/CAM technology for fabricating complete dentures becomes commercially available, it will be possible to scan the denture base morphology and tooth positions recorded with this technique and import those data into a virtual tooth arrangement program where teeth can be articulated and then export the data to a milling device for the fabrication of the complete dentures. A prototype 3-D tooth arrangement program is described in this article that serves as an example of the type of program than can be used to arrange prosthetic teeth virtually as part of the overall CAD/CAM fabrication of complete dentures.

Use of a powered toothbrush for hygiene of edentulous implant-supported prostheses.

Effective professional maintenance and personal oral hygiene are important for the long-term success and comfortable functioning of implant-assisted dental restorations. Incorporating the most effective oral hygiene devices into each patient's oral hygiene regimen facilitates optimal results. The use of a powered toothbrush with interchangeable brush heads permits effective cleaning of the most access-challenging prosthesis contours. This article presents a useful personal oral hygiene regimen for the long-term maintenance of various implant-supported dental restorations.

Maxillary overlay removable partial dentures for the restoration of worn teeth.

Prolonged tooth maintenance by a more aged population considerably increases the probability of dentists having to treat patients with high levels of tooth wear. Pathological tooth wear, caused primarily by parafunction, seems to be a growing problem that affects a large number of adult patients. The clinical report presents a case of a partially edentulous patient with an elevated degree of wear in the upper jaw caused by attrition and erosion, rehabilitated with a maxillary overlay removable partial denture (ORPD) consisting of a chrome-cobalt (Cr-Co) framework with anterior acrylic resin veneers, posterior cast overlays, and acrylic resin denture bases. Removable partial prosthesis is a treatment alternative when teeth are found to be severely worn or when the patient needs a simple and economical option. Because economics is a conditional factor of the treatment, the clinician should present different treatment alternatives to the patient, in which the overlay prosthesis can be considered.

Restoration of endodontically treated teeth: the seven keys to success.

Preservation of tooth integrity and strength is important for the long-term survival of endodontically treated teeth. Endodontic treatment and post space preparation requires reduction of the remaining supportive tooth structure. Restorative modalities following root canal therapy must provide sufficient strength for the prosthetic material and tooth structures. This article presents seven key factors that should be taken into consideration to ensure clinical success when restoring an endodontically treated tooth.

Implant treatment record form.

The identification of different dental implants and restorative components is difficult when dental records do not include an inventory of implant components. An implant record form is described. The form should be filled out and retained in the patient's chart for future use and implant maintenance visits.

Obtaining maxillomandibular records and definitive impressions in a single visit for a completely edentulous patient with a history of combination syndrome.

Any attempt to reduce the number of dental visits for the fabrication of complete dentures is appreciated by both the dentist and the patient. This article illustrates clinical and laboratory procedures for making a 2-stage definitive impression combined with the recording of maxillomandibular relations in the same visit for a completely edentulous patient with maxillary anterior mobile soft tissues.

Designing successful removable partial dentures.

In today's busy dental offices, removable partial denture design is often abdicated by dentists, both as a result of a lack of experience and consensus of design and because of educational failure on the part of dental schools. The result is delegation of the clinical design process to the lab technician. The lack of clinical data provided to the dental technician jeopardizes the quality of care. This article will focus on a logical and simple approach to this problem, making removable partial denture design simple and predictably achievable. The clinical evidence related to removable partial denture design will be described, along with a checklist to simplify the process and make it practical and applicable to everyday clinical practice.

A simple, predictable intraoral technique for retentive mechanism attachment of implant overdenture attachments.

A technique is presented for intraorally attaching two O-ring attachments to a mandibular complete denture. The technique involves fabricating and placing a mandibular denture with conventional procedures. Patients adapt initially to the complete denture. The attachments are then attached to the denture base with autopolymerizing acrylic resin. This technique provides a predictable method to achieve a tissue-supported and implant-retained overdenture.