Transferring the tooth preparation finish line on intraoral digital scans to dental software programs: A dental technique.

Intraoral scanner software programs allow the clinician to draw the tooth preparation finish lines. However, this information may be lost when importing the digital file into different computer-aided design (CAD) dental software programs. A technique for transferring the marked tooth preparation finish line into an intraoral digital scan is described. The intraoral digital scan of the tooth preparation is duplicated and used to draw the finish line. Subsequently, the tooth preparation geometry is erased while maintaining the finish line border, which will be used as a reference when designing the definitive restoration in the CAD software program.

Prosthetically-Driven Full-Mouth Implant-Supported Prostheses Using Guided Surgical Implant Planning with Composite Resin Markers: A Case Report.

This report describes a prosthetically-driven implant planning method, guided by the alignment procedures between the cone beam computed tomography, intraoral digital scans, and digitized maxillary and mandibular interim complete dentures using intraoral composite resin markers as a common reference. The markers were attached to the keratinized oral mucosa of the edentulous ridges using cyanoacrylate and kept in place during the digitizing procedures. The technique provides a simpler and more economical alternative to conventional prosthetically-driven static implant planning methods.

Hemostatic agents in endodontic surgery of maxillary molars: A randomized controlled pilot study of polytetrafluoroethylene (PTFE) strips as an adjunct to epinephrine impregnated gauze versus aluminum chloride

BACKGROUND: Hemostasis is of critical importance in endodontic surgery. Studies on bleeding control in maxillary molars are scarce. The present study compares the efficacy of two hemostatic techniques in controlling bleeding in endodontic surgery. MATERIAL AND METHODS: A randomized two-arm pilot study involving 30 patients with peri-radicular lesions in maxillary molars (first and second molars) was carried out including the following hemostatic agents: polytetrafluoroethylene (PTFE) strips as an adjunct to epinephrine impregnated gauze (test group; n = 15) and aluminum chloride (Expasyl(TM)) (control; n = 15). Bleeding control was independently assessed by the surgeon and by two blinded observers before and after application of the hemostatic agent, and was classified as either adequate (complete bleeding control) or inadequate (incomplete bleeding control). RESULTS: Bleeding control was similar in both groups. Simple binary logistic regression analysis failed to identify variables affecting bleeding control. Only the height of the keratinized mucosal band (≥ 2 mm) suggested a decreased risk of inadequate bleeding control of up to 89% (OR = 0.11; p = 0.06). CONCLUSIONS: No difference in the efficacy of bleeding control was observed between PTFE strips as an adjunct to epinephrine impregnated gauze and aluminum chloride in maxillary molars

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In vitro comparison of the efficacy of two fractured implant-prosthesis screw extraction methods: Conventional versus mechanical.

STATEMENT OF PROBLEM: Implant-supported prostheses may be subject to esthetic, biological, or mechanical complications. Protocols for dealing with these mechanical problems are sparse. PURPOSE: The purpose of this in vitro study was to compare the efficacy of a mechanical system for extracting fractured implant-prosthesis screws with the conventional method. MATERIAL AND METHODS: A total of 60 screws were divided into 2 groups according to their morphology (flat screws with a smooth shaft and threaded apical area and screws with a completely threaded body) and subjected to fatiguing and static load testing until fracture. The specimens were assigned to 3 operators with varying levels of clinical experience (high, medium, low) in extracting fractured screws by using the conventional method (explorer and ultrasound device) and a mechanical method (extractor kit). The extraction event (whether the screw fragment was extracted or not within 10 minutes) was recorded, and the time taken to perform the extraction was measured for each method in relation to screw type, operator experience, and damage to the threads. The influence of screw morphology, extraction method, operator experience, and fracture type on the time needed to extract a screw fragment was assessed with the Mann-Whitney and Kruskal-Wallis tests. Thread damage was compared by using the Fisher's exact test and the Kruskal-Wallis test (α=.05). RESULTS: The mechanical method was more effective for screw extraction than the conventional method (P=.032). Screw morphology also had a significant influence on extraction, whereby the screw design with apical thread took less time to extract (P=.022). Coronal fractures had a higher probability of extraction than apical fractures (P=.05). CONCLUSIONS: Mechanical extraction is more effective for extracting fractured implant-prosthetic screws, showing a higher probability of extraction than the conventional method. Prosthetic fixing screws with a smooth shaft and threaded apical area are the easiest to extract.

Analogical and Digital Workflow in the Design and Preparation of the Emergence Profile of Biologically Oriented Preparation Technique (BOPT) Crowns over Implants in the Working Model.

: The Biologically Oriented Preparation Technique (BOPT), developed by Ignacio Loi and published in 2008, is a consolidated concept in the modeling and preservation of pericoronal soft tissues. The present study describes the analogical and digital methods allowing adequate design and preparation of the emergence profile of BOPT crowns in the working model, with a view to comparing the workflow and advantages of each method. At present, not all the digital procedures have been fully optimized to completely replace the traditional analogical methods. Nevertheless, it is only a matter of time until dental digitalization technology totally replaces the analogical clinical methods. The digital workflow for this procedure is quickly implemented and optimized, and represents the most realistic option, with possibilities for further development in the immediate future.

Volumetric variation of peri-implant soft tissues in convergent collar implants and crowns using the biologically oriented preparation technique (BOPT)

Background: To evaluate the changes in the peri-implant soft tissues of convergent collar implants with biologically oriented preparation technique (BOPT) crowns, 10 months after loading. Material and Methods: A pilot study was carried out from January 2016 to October 2017 involving 14 patients with one or two implants in the posterior mandibular sector. A total of 32 convergent collar implants were placed using a non-submerged protocol. Three months later the provisional cemented crowns were fitted using the BOPT approach with the finish line 1-1.5 mm below the gingival margin, simulating coronal emergence of a natural tooth. The soft tissue changes were measured with an intraoral scanner at two different time points: a) on the day of provisionalization, before prosthetic loading; and b) 10 months later without the provisional prosthesis. The STL files were superimposed and the soft tissue changes were recorded using a color scale with measurement of the volumetric changes in mm3 Results: A mean increase in peri-implant mucosal volume of 64.7 mm3 was observed in 29 implants. The zones with the greatest increase in soft tissue volume were the papillae of implants with adjacent teeth and the peri-implant buccal margin. Three implants showed a mean decrease in soft tissue volume of -25.1 mm3. Conclusions: The fitting and design of crowns using the biologically oriented preparation technique (BOPT) over convergent collar implants affords a significant increase in peri-implant soft tissue volume both at the level of the papillae and in the buccal margin

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